update Changelog

corrected link to the diagram in md file

.github/workflows/container-build.yaml

@@ -0,0 +1,63 @@
+name: Create and publish Container image
+
+on:
+  push:
+    branches:
+      - master
+    tags:
+      - 'v*'
+  pull_request:
+    branches:
+      - master
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to Container registry
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=edge
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+
+      - name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          platforms: linux/amd64,linux/386,linux/arm64,linux/arm/v6,linux/arm/v7
+          context: .
+          file: Dockerfile
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

.gitignore

@@ -3,8 +3,15 @@
 *.o
 cscope.*
 echosrv
+libsslh.a
 sslh-fork
 sslh-select
+sslh-ev
+systemd-sslh-generator
 sslh.8.gz
 tags
 version.h
+/config.status
+/config.log
+/config.h
+/Makefile

ChangeLog

@@ -1,3 +1,58 @@
+v2.1.3:
+	Fix Landlock access to /etc/hosts.deny and
+	/etc/hosts.allow.
+
+v2.1.2:
+	Fix inetd mode.
+
+v2.1.1:
+	Various minor fixes.
+
+v2.1.0:
+	Support for the Landlock LSM. After initial setup,
+	sslh gives up all local file access rights.
+
+	Reintroduced --ssl as an alias to --tls.
+
+	Introduce autoconf to adapt to landlock presence.
+
+	Close connexion without error message if remote
+	client forcefully closes connexion, for Windows.
+
+v2.0.1:	
+	Fix resolve_on_forward setting, which would crash
+	sslh reliably.
+
+v2.0.0:
+v2.0:
+	New sslh-ev: this is functionally equivalent to
+	sslh-select (mono-process, only forks for specified
+	protocols), but based on libev, which should make it
+	scalable to large numbers of connections.
+
+	New log system: instead of --verbose with arbitrary
+	levels, there are now several message classes. Each
+	message class can be set to go to stderr, syslog, or
+	both. Classes are documented in example.cfg.
+
+	UDP connections are now managed in a hash to avoid
+	linear searches. The downside is that the number of
+	UDP connections is a hard limit, configurable with
+	the 'udp_max_connections', which defaults to 1024.
+	Timeouts are managed with lists.
+
+	inetd merges stderr output to what is sent to the
+	client, which is a security issue as it might give
+	information to an attacker. When inetd is activated,
+	stderr is forcibly closed.
+
+	New protocol-level option `resolve_on_forward`,
+	requests that target names are resolved at each
+	connection instead of at startup. Useful for dynamic
+	DNS situations. (Paul Schroeder/milkpirate)
+
+	New probe for MSRDP (akappner).
+
 v1.22: 17AUG2021
 	sslh-select now supports UDP protocols.
 	Probes specified in the `protocols`
@@ -12,7 +67,7 @@ v1.22: 17AUG2021
 	combined with incoming TLS with SNI.  UDP clients
 	and servers need to agree on the IPv4/IPv6 they use:
 	use the same protocol on all sides! Often, this
-	means explicitely using 'ip4-localhost'.
+	means explicitly using 'ip4-localhost'.
 	UDP sender-receiver pairs (connections, so to speak)
 	are kept for 60s, which can be changed with
 	`udp_timeout` in the configuration.
@@ -54,7 +109,7 @@ v1.21: 11JUL2020
 
 	Added TCP_FASTOPEN support for client sockets (if
 	tfo_ok is specified in their configuration) and for
-	listenint socket, if all client protocols support it.
+	listening socket, if all client protocols support it.
 	(Craig Andrews)
 
 	Added 'minlength' option to skip a probe if less
@@ -80,8 +135,8 @@ v1.20: 20NOV2018
 	Before, probes were tried in order, repeating on the
 	same probe as long it returned PROBE_AGAIN before
 	moving to the next one. This means a probe which
-	requires a lot of data (i.e. returne PROBE_AGAIN for
-	a long time) could prevent sucessful matches from 
+	requires a lot of data (i.e. return PROBE_AGAIN for
+	a long time) could prevent successful matches from 
 	subsequent probes. The configuration file needed to
 	take that into account.
 
@@ -142,7 +197,7 @@ v1.18:	29MAR2016
 v1.17: 	09MAR2015
 	Support RFC5952-style IPv6 addresses, e.g. [::]:443.
 
-	Transparant proxy support for FreeBSD.
+	Transparent proxy support for FreeBSD.
 	(Ruben van Staveren)
 
 	Using -F with no argument will try
@@ -171,7 +226,7 @@ v1.16:	11FEB2014
 
 	Libcap support: Keep only CAP_NET_ADMIN if started
 	as root with transparent proxying and dropping
-	priviledges (enable USELIBCAP in Makefile). This
+	privileges (enable USELIBCAP in Makefile). This
 	avoids having to mess with filesystem capabilities.
 	(Sebastian Schmidt/yath)
 
@@ -180,7 +235,7 @@ v1.16:	11FEB2014
 	actual errors if connections are dropped before
 	getting to getpeername).
 
-	Set IP_FREEDBIND if available to bind to addresses
+	Set IP_FREEBIND if available to bind to addresses
 	that don't yet exist.
 
 v1.15:	27JUL2013
@@ -265,7 +320,7 @@ v1.11: 21APR2012
 	--user isn't specified, just run as current user.
 
 	No longer create PID file by default, it should be
-	explicitely set with --pidfile.
+	explicitly set with --pidfile.
 
 	No longer log to syslog if in foreground. Logs are
 	instead output to stderr.
@@ -356,7 +411,7 @@ v1.8: 15JUL2011
 v1.7: 01FEB2010
 	Added CentOS init.d script (Andre Krajnik).
 
-	Fixed default ssl address inconsistancy, now
+	Fixed default ssl address inconsistency, now
 	defaults to "localhost:443" and fixed documentation
 	accordingly (pointed by Markus Schalke).
 

Dockerfile

@@ -1,23 +1,38 @@
-FROM alpine:latest as build
+ARG ALPINE_VERSION="latest"
+ARG TARGET_ARCH="library"
 
-ADD . /sslh
+FROM docker.io/${TARGET_ARCH}/alpine:${ALPINE_VERSION} AS build
 
-RUN \
-  apk add \
-    gcc \
-    libconfig-dev \
-    make \
-    musl-dev \
-    pcre-dev \
-    perl && \
-  cd /sslh && \
-  make sslh-select && \
-  strip sslh-select
+WORKDIR /sslh
 
-FROM alpine:latest
+RUN apk add --no-cache \
+        'gcc' \
+        'libconfig-dev' \
+        'make' \
+        'musl-dev' \
+        'pcre2-dev' \
+        'perl' \
+        ;
 
-COPY --from=build /sslh/sslh-select /sslh
+COPY . /sslh
 
-RUN apk --no-cache add libconfig pcre
+RUN ./configure && make sslh-select && strip sslh-select
 
-ENTRYPOINT [ "/sslh", "--foreground"]
+FROM docker.io/${TARGET_ARCH}/alpine:${ALPINE_VERSION}
+
+COPY --from=build "/sslh/sslh-select" "/usr/local/bin/sslh"
+RUN apk add --no-cache \
+        'libconfig' \
+        'pcre2' \
+        'iptables' \
+        'ip6tables' \
+        'libcap' \
+    && \
+    adduser -s '/bin/sh' -S -D sslh && \
+    setcap cap_net_bind_service,cap_net_raw+ep /usr/local/bin/sslh
+
+COPY "./container-entrypoint.sh" "/init"
+ENTRYPOINT [ "/init" ]
+
+# required for updating iptables
+USER root:root

Makefile.in

@@ -3,8 +3,11 @@ VERSION=$(shell ./genver.sh -r)
 
 # Configuration -- you probably need to `make clean` if you
 # change any of these
+# landlock is checked by `configure` and set in config.h
+ENABLE_SANITIZER= # Enable ASAN/LSAN/UBSAN
 ENABLE_REGEX=1  # Enable regex probes
 USELIBCONFIG=1	# Use libconfig? (necessary to use configuration files)
+USELIBEV=1	# Use libev?
 USELIBWRAP?=	# Use libwrap?
 USELIBCAP=	# Use libcap?
 USESYSTEMD=     # Make use of systemd socket activation
@@ -19,15 +22,25 @@ MAN=sslh.8.gz	# man page name
 # End of configuration -- the rest should take care of
 # itself
 
+ifneq ($(strip $(ENABLE_SANITIZER)),)
+    CFLAGS_SAN=-fsanitize=address -fsanitize=leak -fsanitize=undefined
+endif
+
 ifneq ($(strip $(COV_TEST)),)
     CFLAGS_COV=-fprofile-arcs -ftest-coverage
 endif
 
 CC ?= gcc
-CFLAGS ?=-Wall -DLIBPCRE -g $(CFLAGS_COV)
+AR ?= ar
+CFLAGS +=-Wall -O2 -DLIBPCRE -g $(CFLAGS_COV) $(CFLAGS_SAN)
+
 
 LIBS=-lm -lpcre2-8
-OBJS=sslh-conf.o common.o sslh-main.o probe.o tls.o argtable3.o udp-listener.o collection.o gap.o
+OBJS=sslh-conf.o common.o log.o sslh-main.o probe.o tls.o argtable3.o collection.o gap.o tcp-probe.o landlock.o
+OBJS_A=libsslh.a
+FORK_OBJS=sslh-fork.o $(OBJS_A)
+SELECT_OBJS=processes.o udp-listener.o sslh-select.o hash.o tcp-listener.o $(OBJS_A)
+EV_OBJS=processes.o udp-listener.o sslh-ev.o hash.o tcp-listener.o $(OBJS_A)
 
 CONDITIONAL_TARGETS=
 
@@ -61,39 +74,52 @@ ifneq ($(strip $(USELIBBSD)),)
         CPPFLAGS+=-DLIBBSD
 endif
 
+ifneq ($(strip $(USELIBEV)),)
+        CONDITIONAL_TARGETS+=sslh-ev
+endif
 
-all: sslh $(MAN) echosrv $(CONDITIONAL_TARGETS)
+all: sslh-fork sslh-select $(MAN) echosrv $(CONDITIONAL_TARGETS)
 
-.c.o: *.h version.h
-	$(CC) $(CFLAGS) $(CPPFLAGS) -c $<
+%.o: %.c %.h version.h
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
+
+$(OBJS_A): $(OBJS)
+	$(AR) rcs $(OBJS_A) $(OBJS)
 
 version.h:
 	./genver.sh >version.h
 
-sslh: sslh-fork sslh-select
+$(OBJS) $(FORK_OBJS) $(SELECT_OBJS) $(EV_OBJS): argtable3.h collection.h common.h gap.h hash.h log.h probe.h processes.h sslh-conf.h tcp-listener.h tcp-probe.h tls.h udp-listener.h version.h
 
-$(OBJS): version.h common.h collection.h sslh-conf.h gap.h
+
+c2s:
+	conf2struct sslhconf.cfg
+	conf2struct echosrv.cfg
 
 sslh-conf.c sslh-conf.h: sslhconf.cfg
-	conf2struct sslhconf.cfg
+	$(warning "sslhconf.cfg is more recent than sslh-conf.[ch]. Use `make c2s` to rebuild using `conf2struct`")
 
-sslh-fork: version.h $(OBJS) sslh-fork.o Makefile
-	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-fork sslh-fork.o $(OBJS) $(LIBS)
-	#strip sslh-fork
+sslh-fork: version.h Makefile $(FORK_OBJS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-fork $(FORK_OBJS) $(LIBS)
 
-sslh-select: version.h $(OBJS) sslh-select.o Makefile
-	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-select sslh-select.o $(OBJS) $(LIBS)
-	#strip sslh-select
+sslh-select: version.h $(SELECT_OBJS) Makefile
+	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-select $(SELECT_OBJS) $(LIBS)
+
+sslh-ev: version.h $(EV_OBJS) Makefile
+	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-ev $(EV_OBJS) $(LIBS) -lev
 
 systemd-sslh-generator: systemd-sslh-generator.o
 	$(CC) $(CFLAGS) $(LDFLAGS) -o systemd-sslh-generator systemd-sslh-generator.o -lconfig
 
 echosrv-conf.c echosrv-conf.h: echosrv.cfg
-	conf2struct echosrv.cfg
+	$(warning "echosrv.cfg is more recent than echosrv-conf.[ch]. Use `make c2s` to rebuild using `conf2struct`")
 
 echosrv: version.h echosrv-conf.c echosrv.o echosrv-conf.o argtable3.o
 	$(CC) $(CFLAGS) $(LDFLAGS) -o echosrv echosrv.o echosrv-conf.o argtable3.o $(LIBS)
 
+
+landlock.o: config.h
+
 $(MAN): sslh.pod Makefile
 	pod2man --section=8 --release=$(VERSION) --center=" " sslh.pod | gzip -9 - > $(MAN)
 
@@ -113,7 +139,7 @@ docker-clean:
 	yes | docker image prune
 
 # generic install: install binary and man page
-install: sslh $(MAN)
+install: sslh-fork $(MAN)
 	mkdir -p $(DESTDIR)/$(BINDIR)
 	mkdir -p $(DESTDIR)/$(MANDIR)
 	install -p sslh-fork $(DESTDIR)/$(BINDIR)/sslh
@@ -133,7 +159,7 @@ distclean: clean
 	rm -f tags sslh-conf.[ch] echosrv-conf.[ch] cscope.*
 
 clean:
-	rm -f sslh-fork sslh-select echosrv version.h $(MAN) systemd-sslh-generator *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info
+	rm -f sslh-fork sslh-select $(CONDITIONAL_TARGETS) echosrv version.h $(MAN) systemd-sslh-generator *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info
 
 tags:
 	ctags --globals -T *.[ch]

README.md

@@ -11,7 +11,7 @@ protocol that can be tested using a regular expression, can
 be recognised. A typical use case is to allow serving
 several services on port 443 (e.g. to connect to SSH from
 inside a corporate firewall, which almost never block port
-443) while still serving HTTPS on that port. 
+443) while still serving HTTPS on that port.
 
 Hence `sslh` acts as a protocol demultiplexer, or a
 switchboard. With the SNI and ALPN probe, it makes a good
@@ -20,9 +20,10 @@ address.
 
 `sslh` has the bells and whistles expected from a mature
 daemon: privilege and capabilities dropping, inetd support,
-systemd support, transparent proxying, chroot, logging, 
-IPv4 and IPv6, TCP and UDP, a fork-based and a select-based 
-model, and more.
+systemd support, transparent proxying, chroot, logging,
+IPv4 and IPv6, TCP and UDP, a fork-based, a select-based
+model, and yet another based on libev for larger
+installations.
 
 Install
 =======
@@ -35,6 +36,34 @@ Configuration
 
 Please refer to the [configuration guide](doc/config.md).
 
+Transparent proxying
+--------------------
+
+Transparent proxying allows the target server to see the
+original client IP address, i.e. `sslh` becomes invisible.
+
+This means services behind `sslh` (Apache, `sshd` and so on)
+will see the external IP and ports as if the external world
+connected directly to them. This simplifies IP-based access
+control (or makes it possible at all), and makes it possible
+to use IP-based banning tools such as `fail2ban`.
+
+There are two methods. One uses additional virtual network
+interfaces. The principle and basic setup is described
+[here](doc/simple_transparent_proxy.md), with further
+scenarios described [there](doc/scenarios-for-simple-transparent-proxy.md).
+
+
+Another method uses iptable packet marking features, and is
+highly dependent on your network environment and
+infrastructure setup. There is no known generic approach,
+and if you do not find directions for your exact setup, you
+will probably need an extensive knowledge of network
+management and iptables setup".
+
+It is described in its own [document](doc/tproxy.md).
+In most cases, you will be better off following the first
+method.
 
 
 Docker image
@@ -44,45 +73,120 @@ How to use
 
 ---
 
-Build docker image
-
-    make docker
-
 
 ```bash
-docker container run \
+docker run \
+  --cap-add CAP_NET_RAW \
+  --cap-add CAP_NET_BIND_SERVICE \
   --rm \
   -it \
+  ghcr.io/yrutschle/sslh:latest \
+  --foreground \
   --listen=0.0.0.0:443 \
   --ssh=hostname:22 \
-  --tlshostname:443 \
-  sslh:latest
+  --tls=hostname:443
 ```
 
 docker-compose example
 
-```
----
+```yaml
 version: "3"
 
 services:
   sslh:
-    image: sslh:latest
+    image: ghcr.io/yrutschle/sslh:latest
     hostname: sslh
     ports:
-      - 443:443/tcp
-    command: --listen=0.0.0.0:443 --tlshostname:443 --openvpn=openvpn:1194
+      - 443:443
+    command: --foreground --listen=0.0.0.0:443 --tls=nginx:443 --openvpn=openvpn:1194
     depends_on:
       - nginx
       - openvpn
 
   nginx:
     image: nginx
-    hostname: nginx
+
+  openvpn:
+    image: openvpn
+```
+
+Transparent mode 1: using sslh container for networking
+
+_Note: For transparent mode to work, the sslh container must be able to reach your services via **localhost**_
+```yaml
+version: "3"
+
+services:
+  sslh:
+    build: https://github.com/yrutschle/sslh.git
+    container_name: sslh
+    environment:
+      - TZ=${TZ}
+    cap_add:
+      - NET_ADMIN
+      - NET_RAW
+      - NET_BIND_SERVICE
+    sysctls:
+      - net.ipv4.conf.default.route_localnet=1
+      - net.ipv4.conf.all.route_localnet=1
+    command: --transparent --foreground --listen=0.0.0.0:443 --tls=localhost:8443 --openvpn=localhost:1194
+    ports:
+      - 443:443 #sslh
+
+      - 80:80 #nginx
+      - 8443:8443 #nginx
+
+      - 1194:1194 #openvpn
+    extra_hosts:
+      - localbox:host-gateway
+    restart: unless-stopped
+
+  nginx:
+    image: nginx:latest
+    .....
+    network_mode: service:sslh #set nginx container to use sslh networking.
+    # ^^^ This is required. This makes nginx reachable by sslh via localhost
+  
+  openvpn:
+    image: openvpn:latest
+    .....
+    network_mode: service:sslh #set openvpn container to use sslh networking
+```
+
+Transparent mode 2: using host networking
+
+```yaml
+version: "3"
+
+services:
+  sslh:
+    build: https://github.com/yrutschle/sslh.git
+    container_name: sslh
+    environment:
+      - TZ=${TZ}
+    cap_add:
+      - NET_ADMIN
+      - NET_RAW
+      - NET_BIND_SERVICE
+    # must be set manually
+    #sysctls:
+    #  - net.ipv4.conf.default.route_localnet=1
+    #  - net.ipv4.conf.all.route_localnet=1
+    command: --transparent --foreground --listen=0.0.0.0:443 --tls=localhost:8443 --openvpn=localhost:1194
+    network_mode: host
+    restart: unless-stopped
+  
+  nginx:
+    image: nginx:latest
+    .....
+    ports:
+      - 8443:8443 # bind to docker host on port 8443
 
   openvpn:
     image: openvpn:latest
-    hostname: openvpn
+    .....
+    ports:
+      - 1194:1194 # bind to docker host on port 1194
 ```
 
 Comments? Questions?

argtable3.c

@@ -2876,9 +2876,9 @@ static void arg_file_resetfn(struct arg_file* parent) {
 static const char* arg_basename(const char* filename) {
     const char *result = NULL, *result1, *result2;
 
-    /* Find the last occurrence of eother file separator character. */
-    /* Two alternative file separator chars are supported as legal  */
-    /* file separators but not both together in the same filename.  */
+    /* Find the last occurrence of other file separator character. */
+    /* Two alternative file separator chars are supported as legal */
+    /* file separators but not both together in the same filename. */
     result1 = (filename ? strrchr(filename, FILESEPARATOR1) : NULL);
     result2 = (filename ? strrchr(filename, FILESEPARATOR2) : NULL);
 
@@ -2927,7 +2927,7 @@ static int arg_file_scanfn(struct arg_file* parent, const char* argval) {
     } else if (!argval) {
         /* a valid argument with no argument value was given. */
         /* This happens when an optional argument value was invoked. */
-        /* leave parent arguiment value unaltered but still count the argument. */
+        /* leave parent argument value unaltered but still count the argument. */
         parent->count++;
     } else {
         parent->filename[parent->count] = argval;
@@ -3173,7 +3173,7 @@ static int arg_int_scanfn(struct arg_int* parent, const char* argval) {
     } else if (!argval) {
         /* a valid argument with no argument value was given. */
         /* This happens when an optional argument value was invoked. */
-        /* leave parent arguiment value unaltered but still count the argument. */
+        /* leave parent argument value unaltered but still count the argument. */
         parent->count++;
     } else {
         long int val;
@@ -3813,8 +3813,8 @@ static const TRexChar* g_nnames[] = {_SC("NONE"),    _SC("OP_GREEDY"), _SC("OP_O
 #endif
 #define OP_GREEDY (MAX_CHAR + 1)  /*  * + ? {n} */
 #define OP_OR (MAX_CHAR + 2)
-#define OP_EXPR (MAX_CHAR + 3)       /* parentesis () */
-#define OP_NOCAPEXPR (MAX_CHAR + 4)  /* parentesis (?:) */
+#define OP_EXPR (MAX_CHAR + 3)       /* parenthesis () */
+#define OP_NOCAPEXPR (MAX_CHAR + 4)  /* parenthesis (?:) */
 #define OP_DOT (MAX_CHAR + 5)
 #define OP_CLASS (MAX_CHAR + 6)
 #define OP_CCLASS (MAX_CHAR + 7)
@@ -5313,7 +5313,7 @@ static void arg_parse_untagged(int argc, char** argv, struct arg_hdr** table, st
         }
     }
 
-    /* if a tenative error still remains at this point then register it as a proper error */
+    /* if a tentative error still remains at this point then register it as a proper error */
     if (errorlast) {
         arg_register_error(endtable, parentlast, errorlast, optarglast);
         optind++;
@@ -5384,7 +5384,7 @@ int arg_parse(int argc, char** argv, void** argtable) {
     /*
         Fill in the local copy of argv[]. We need a local copy
         because getopt rearranges argv[] which adversely affects
-        susbsequent parsing attempts.
+        subsequent parsing attempts.
         */
     for (i = 0; i < argc; i++)
         argvcopy[i] = argv[i];
@@ -5451,7 +5451,7 @@ static void arg_cat_option(char* dest, size_t ndest, const char* shortopts, cons
     if (shortopts) {
         char option[3];
 
-        /* note: option array[] is initialiazed dynamically here to satisfy   */
+        /* note: option array[] is initialized dynamically here to satisfy   */
         /* a deficiency in the watcom compiler wrt static array initializers. */
         option[0] = '-';
         option[1] = shortopts[0];
@@ -5509,7 +5509,7 @@ static void arg_cat_optionv(char* dest, size_t ndest, const char* shortopts, con
             /* "-a|-b|-c" */
             char shortopt[3];
 
-            /* note: shortopt array[] is initialiazed dynamically here to satisfy */
+            /* note: shortopt array[] is initialized dynamically here to satisfy */
             /* a deficiency in the watcom compiler wrt static array initializers. */
             shortopt[0] = '-';
             shortopt[1] = *c;
@@ -5881,7 +5881,7 @@ static void arg_print_formatted_ds(arg_dstr_t ds, const unsigned lmargin, const
  * Prints the glossary in strict GNU format.
  * Differences to arg_print_glossary() are:
  *   - wraps lines after 80 chars
- *   - indents lines without shortops
+ *   - indents lines without shortopts
  *   - does not accept formatstrings
  *
  * Contributed by Uli Fouquet
@@ -5956,7 +5956,7 @@ int arg_nullcheck(void** argtable) {
  * that entry were still allocated ok. Those subsequent allocations will not be
  * deallocated by arg_free().
  * Despite the unlikeliness of the problem occurring, and the even unlikelier event
- * that it has any deliterious effect, it is fixed regardless by replacing arg_free()
+ * that it has any deleterious effect, it is fixed regardless by replacing arg_free()
  * with the newer arg_freetable() function.
  * We still keep arg_free() for backwards compatibility.
  */

argtable3.h

@@ -87,7 +87,7 @@ typedef int(arg_comparefn)(const void* k1, const void* k2);
  * that particular arg_xxx arguments, performing post-parse checks, and
  * reporting errors.
  * These functions are private to the individual arg_xxx source code
- * and are the pointer to them are initiliased by that arg_xxx struct's
+ * and are the pointer to them are initialised by that arg_xxx struct's
  * constructor function. The user could alter them after construction
  * if desired, but the original intention is for them to be set by the
  * constructor and left unaltered.
@@ -95,7 +95,7 @@ typedef int(arg_comparefn)(const void* k1, const void* k2);
 typedef struct arg_hdr {
     char flag;             /* Modifier flags: ARG_TERMINATOR, ARG_HASVALUE. */
     const char* shortopts; /* String defining the short options */
-    const char* longopts;  /* String defiing the long options */
+    const char* longopts;  /* String defining the long options */
     const char* datatype;  /* Description of the argument data type */
     const char* glossary;  /* Description of the option as shown by arg_print_glossary function */
     int mincount;          /* Minimum number of occurences of this option accepted */

basic.cfg

@@ -1,29 +1,33 @@
 # This is a basic configuration file that should provide
 # sensible values for "standard" setup.
 
-verbose: 0;
-foreground: false;
-inetd: false;
-numeric: false;
-transparent: false;
+# You will find extensive examples with explanations in
+# example.cfg
+
 timeout: 2;
 user: "nobody";
 pidfile: "/var/run/sslh.pid";
-chroot: "/var/empty";
 
 
-# Change hostname with your external address name.
+# Change hostname with your external address name, or the IP
+# of the interface that receives connections
+# Default is to bind all interfaces. httpd can be started
+# first to bind on localhost, in which case sslh will bind
+# only other interfaces.
 listen:
 (
-    { host: "thelonious"; port: "443"; }
+    { host: "0.0.0.0"; port: "443"; },
+    { host: "[::]"; port: "443"; }
 );
 
+
+# Change to the protocols you want to forward to. The
+# defaults here are sensible for services running on
+# localhost
 protocols:
 (
      { name: "ssh"; service: "ssh"; host: "localhost"; port: "22"; fork: true; },
      { name: "openvpn"; host: "localhost"; port: "1194"; },
-     { name: "xmpp"; host: "localhost"; port: "5222"; },
-     { name: "http"; host: "localhost"; port: "80"; },
      { name: "tls"; host: "localhost"; port: "443"; log_level: 0; },
      { name: "anyprot"; host: "localhost"; port: "443"; }
 );

common.c

@@ -4,7 +4,6 @@
  * No code here should assume whether sockets are blocking or not.
  **/
 
-#define SYSLOG_NAMES
 #define _GNU_SOURCE
 #include <stddef.h>
 #include <stdarg.h>
@@ -16,6 +15,7 @@
 
 #include "common.h"
 #include "probe.h"
+#include "log.h"
 #include "sslh-conf.h"
 
 /* Added to make the code compilable under CYGWIN
@@ -42,8 +42,6 @@ struct sslhcfg_item cfg;
 struct addrinfo *addr_listen = NULL; /* what addresses do we listen to? */
 
 
-static int do_syslog = 1; /* Should we syslog? controled by syslog_facility = "none" */
-
 #ifdef LIBWRAP
 #include <tcpd.h>
 int allow_severity =0, deny_severity = 0;
@@ -60,7 +58,7 @@ void check_res_dump(CR_ACTION act, int res, struct addrinfo *addr, char* syscall
     char buf[NI_MAXHOST];
 
     if (res == -1) {
-        fprintf(stderr, "%s:%s: %s\n",
+        print_message(msg_system_error, "%s:%s: %s\n",
                 sprintaddr(buf, sizeof(buf), addr),
                 syscall,
                 strerror(errno));
@@ -77,7 +75,7 @@ int get_fd_sockets(struct listen_endpoint *sockfd[])
 #ifdef SYSTEMD
     sd = sd_listen_fds(0);
     if (sd < 0) {
-      fprintf(stderr, "sd_listen_fds(): %s\n", strerror(-sd));
+      print_message(msg_system_error, "sd_listen_fds(): %s\n", strerror(-sd));
       exit(1);
     }
     if (sd > 0) {
@@ -112,7 +110,7 @@ int make_listen_tfo(int s)
     return setsockopt(s, SOL_SOCKET, TCP_FASTOPEN, (char*)&qlen, sizeof(qlen));
 }
 
-/* Starts listening on a single address 
+/* Starts listening on a single address
  * Returns a socket filehandle, or dies with message in case of major error */
 int listen_single_addr(struct addrinfo* addr, int keepalive, int udp)
 {
@@ -177,7 +175,7 @@ int start_listen_sockets(struct listen_endpoint *sockfd[])
 
     *sockfd = NULL;
 
-    if (cfg.verbose) fprintf(stderr, "Listening to:\n");
+    print_message(msg_config, "Listening to:\n");
 
     for (i = 0; i < cfg.listen_len; i++) {
         keepalive = cfg.listen[i].keepalive;
@@ -191,10 +189,9 @@ int start_listen_sockets(struct listen_endpoint *sockfd[])
             *sockfd = realloc(*sockfd, num_addr * sizeof(*sockfd[0]));
             (*sockfd)[num_addr-1].socketfd = listen_single_addr(addr, keepalive, udp);
             (*sockfd)[num_addr-1].type = udp ? SOCK_DGRAM : SOCK_STREAM;
-            if (cfg.verbose)
-                fprintf(stderr, "%d:\t%s\t[%s] [%s]\n", (*sockfd)[num_addr-1].socketfd, sprintaddr(buf, sizeof(buf), addr),
-                        cfg.listen[i].keepalive ? "keepalive" : "",
-                        cfg.listen[i].is_udp ? "udp" : "");
+            print_message(msg_config, "%d:\t%s\t[%s] [%s]\n", (*sockfd)[num_addr-1].socketfd, sprintaddr(buf, sizeof(buf), addr),
+                          cfg.listen[i].keepalive ? "keepalive" : "",
+                          cfg.listen[i].is_udp ? "udp" : "");
         }
         freeaddrinfo(start_addr);
     }
@@ -265,7 +262,7 @@ int bind_peer(int fd, int fd_from)
     /* if the destination is the same machine, there's no need to do bind */
     if (is_same_machine(&from))
         return 0;
-    
+
 #ifndef IP_BINDANY /* use IP_TRANSPARENT */
     res = setsockopt(fd, IPPROTO_IP, IP_TRANSPARENT, &trans, sizeof(trans));
     CHECK_RES_DIE(res, "setsockopt IP_TRANSPARENT");
@@ -281,7 +278,26 @@ int bind_peer(int fd, int fd_from)
     }
 #endif /* IP_TRANSPARENT / IP_BINDANY */
     res = bind(fd, from.ai_addr, from.ai_addrlen);
-    CHECK_RES_RETURN(res, "bind", res);
+    if (res == -1) {
+        if (errno != EADDRINUSE) {
+            print_message(msg_system_error, "%s:%d:%s:%d:%s\n", __FILE__, __LINE__,
+                        "bind", errno, strerror(errno));
+            return res;
+        }
+
+        /*
+         * If there is more than one transparent mode proxy going on, such as
+         * using sslh as the target of stunnel also in transparent mode, then
+         * the (ip,port) combination will already be bound for the previous application.
+         * In that case, the best we can do is bind with a different port.
+         * This does mean the local server can't use the ident protocol as the port will
+         * have changed, but most people won't care.
+         * Also note that stunnel uses the same logic for the same situation.
+         */
+        ((struct sockaddr_in *)from.ai_addr)->sin_port = 0;
+        res = bind(fd, from.ai_addr, from.ai_addrlen);
+        CHECK_RES_RETURN(res, "bind", res);
+    }
 
     return 0;
 }
@@ -322,19 +338,23 @@ int connect_addr(struct connection *cnx, int fd_from, connect_blocking blocking)
     res = getpeername(fd_from, from.ai_addr, &from.ai_addrlen);
     CHECK_RES_RETURN(res, "getpeername", res);
 
+    if (cnx->proto->resolve_on_forward) {
+        resolve_split_name(&(cnx->proto->saddr), cnx->proto->host,
+                           cnx->proto->port);
+    }
+
     for (a = cnx->proto->saddr; a; a = a->ai_next) {
         /* When transparent, make sure both connections use the same address family */
         if (transparent && a->ai_family != from.ai_addr->sa_family)
             continue;
-        if (cfg.verbose)
-            fprintf(stderr, "connecting to %s family %d len %d\n",
+        print_message(msg_connections_try, "trying to connect to %s family %d len %d\n",
                     sprintaddr(buf, sizeof(buf), a),
                     a->ai_addr->sa_family, a->ai_addrlen);
 
         /* XXX Needs to match ai_family from fd_from when being transparent! */
         fd = socket(a->ai_family, SOCK_STREAM, 0);
         if (fd == -1) {
-            log_message(LOG_ERR, "forward to %s failed:socket: %s\n",
+            print_message(msg_connections_error, "forward to %s failed:socket: %s\n",
                         cnx->proto->name, strerror(errno));
         } else {
             one = 1;
@@ -347,6 +367,7 @@ int connect_addr(struct connection *cnx, int fd_from, connect_blocking blocking)
 
             if (transparent) {
                 res = bind_peer(fd, fd_from);
+                if (res == -1) close(fd);
                 CHECK_RES_RETURN(res, "bind_peer", res);
             }
             res = connect(fd, a->ai_addr, a->ai_addrlen);
@@ -354,7 +375,7 @@ int connect_addr(struct connection *cnx, int fd_from, connect_blocking blocking)
             /* EINPROGRESS indicates it might take time. If it eventually
              * fails, it'll be caught as a failed read */
             if ((res == -1) && (errno != EINPROGRESS)) {
-                log_message(LOG_ERR, "forward to %s failed:connect: %s\n",
+                print_message(msg_connections_error, "forward to %s failed:connect: %s\n",
                                      cnx->proto->name, strerror(errno));
                 close(fd);
                 continue; /* Try the next address */
@@ -370,20 +391,19 @@ int connect_addr(struct connection *cnx, int fd_from, connect_blocking blocking)
 }
 
 /* Store some data to write to the queue later */
-int defer_write(struct queue *q, void* data, int data_size)
+int defer_write(struct queue *q, void* data, ssize_t data_size)
 {
     char *p;
     ptrdiff_t data_offset = q->deferred_data - q->begin_deferred_data;
-    if (cfg.verbose)
-        fprintf(stderr, "**** writing deferred on fd %d\n", q->fd);
 
+    print_message(msg_fd, "writing deferred on fd %d\n", q->fd);
     p = realloc(q->begin_deferred_data, data_offset + q->deferred_data_size + data_size);
     CHECK_ALLOC(p, "realloc");
 
     q->begin_deferred_data = p;
     q->deferred_data = p + data_offset;
     p += data_offset + q->deferred_data_size;
-    q->deferred_data_size += data_size;
+    q->deferred_data_size += (int)data_size;
     memcpy(p, data, data_size);
 
     return 0;
@@ -395,14 +415,13 @@ int defer_write(struct queue *q, void* data, int data_size)
  * */
 int flush_deferred(struct queue *q)
 {
-    int n;
+    ssize_t n;
 
-    if (cfg.verbose)
-        fprintf(stderr, "flushing deferred data to fd %d\n", q->fd);
+    print_message(msg_fd, "flushing deferred data to fd %d\n", q->fd);
 
     n = write(q->fd, q->deferred_data, q->deferred_data_size);
     if (n == -1)
-        return n;
+        return (int)n;
 
     if (n == q->deferred_data_size) {
         /* All has been written -- release the memory */
@@ -413,10 +432,10 @@ int flush_deferred(struct queue *q)
     } else {
         /* There is data left */
         q->deferred_data += n;
-        q->deferred_data_size -= n;
+        q->deferred_data_size -= (int)n;
     }
 
-    return n;
+    return (int)n;
 }
 
 
@@ -430,11 +449,12 @@ void init_cnx(struct connection *cnx)
 
 void dump_connection(struct connection *cnx)
 {
-    printf("state: %d\n", cnx->state);
-    printf("0: fd %d, %d deferred\n", cnx->q[0].fd, cnx->q[0].deferred_data_size);
-    hexdump(cnx->q[0].deferred_data, cnx->q[0].deferred_data_size);
-    printf("1: fd %d, %d deferred\n", cnx->q[1].fd, cnx->q[1].deferred_data_size);
-    hexdump(cnx->q[1].deferred_data, cnx->q[1].deferred_data_size);
+    print_message(msg_int_error, "type: %s\n", cnx->type == SOCK_DGRAM ? "UDP" : "TCP");
+    print_message(msg_int_error, "state: %d\n", cnx->state);
+    print_message(msg_int_error, "0: fd %d, %d deferred\n", cnx->q[0].fd, cnx->q[0].deferred_data_size);
+    hexdump(msg_int_error, cnx->q[0].deferred_data, cnx->q[0].deferred_data_size);
+    print_message(msg_int_error, "1: fd %d, %d deferred\n", cnx->q[1].fd, cnx->q[1].deferred_data_size);
+    hexdump(msg_int_error, cnx->q[1].deferred_data, cnx->q[1].deferred_data_size);
 }
 
 
@@ -450,7 +470,8 @@ void dump_connection(struct connection *cnx)
 int fd2fd(struct queue *target_q, struct queue *from_q)
 {
    char buffer[BUFSIZ];
-   int target, from, size_r, size_w;
+   int target, from;
+   ssize_t size_r, size_w;
 
    target = target_q->fd;
    from = from_q->fd;
@@ -459,11 +480,10 @@ int fd2fd(struct queue *target_q, struct queue *from_q)
    if (size_r == -1) {
        switch (errno) {
        case EAGAIN:
-           if (cfg.verbose)
-               fprintf(stderr, "reading 0 from %d\n", from);
            return FD_NODATA;
 
        case ECONNRESET:
+       case ENOTSOCK:
        case EPIPE:
            return FD_CNXCLOSED;
        }
@@ -496,7 +516,7 @@ int fd2fd(struct queue *target_q, struct queue *from_q)
 
    CHECK_RES_RETURN(size_w, "write", FD_CNXCLOSED);
 
-   return size_w;
+   return (int)size_w;
 }
 
 /* returns a string that prints the IP and port of the sockaddr */
@@ -511,7 +531,7 @@ char* sprintaddr(char* buf, size_t size, struct addrinfo *a)
                cfg.numeric ? NI_NUMERICHOST | NI_NUMERICSERV : 0 );
 
    if (res) {
-       log_message(LOG_ERR, "sprintaddr:getnameinfo: %s\n", gai_strerror(res));
+       print_message(msg_system_error, "sprintaddr:getnameinfo: %s\n", gai_strerror(res));
        /* Name resolution failed: do it numerically instead */
        res = getnameinfo(a->ai_addr, a->ai_addrlen,
                          host, sizeof(host),
@@ -519,7 +539,7 @@ char* sprintaddr(char* buf, size_t size, struct addrinfo *a)
                          NI_NUMERICHOST | NI_NUMERICSERV);
        /* should not fail but... */
        if (res) {
-           log_message(LOG_ERR, "sprintaddr:getnameinfo(NUM): %s\n", gai_strerror(res));
+           print_message(msg_system_error, "sprintaddr:getnameinfo(NUM): %s\n", gai_strerror(res));
            strcpy(host, "?");
            strcpy(serv, "?");
        }
@@ -531,7 +551,8 @@ char* sprintaddr(char* buf, size_t size, struct addrinfo *a)
 }
 
 /* Turns a hostname and port (or service) into a list of struct addrinfo
- * returns 0 on success, -1 otherwise and logs error
+ * On success, returns 0 
+ * On failure, returns -1 or one of getaddrinfo() codes
  */
 int resolve_split_name(struct addrinfo **out, char* host, char* serv)
 {
@@ -548,7 +569,7 @@ int resolve_split_name(struct addrinfo **out, char* host, char* serv)
    if (host[0] == '[') {
        end = strrchr(host, ']');
        if (!end) {
-           fprintf(stderr, "%s: no closing bracket in IPv6 address?\n", host);
+           print_message(msg_config_error, "%s: no closing bracket in IPv6 address?\n", host);
            return -1;
        }
        host++; /* skip first bracket */
@@ -557,7 +578,7 @@ int resolve_split_name(struct addrinfo **out, char* host, char* serv)
 
    res = getaddrinfo(host, serv, &hint, out);
    if (res)
-      log_message(LOG_ERR, "%s `%s:%s'\n", gai_strerror(res), host, serv);
+      print_message(msg_system_error, "resolve_split_name: %s `%s:%s'\n", gai_strerror(res), host, serv);
    return res;
 }
 
@@ -573,7 +594,7 @@ void resolve_name(struct addrinfo **out, char* fullname)
    /* Find port */
    char *sep = strrchr(fullname, ':');
    if (!sep) { /* No separator: parameter is just a port */
-      fprintf(stderr, "%s: names must be fully specified as hostname:port\n", fullname);
+      print_message(msg_config_error, "%s: names must be fully specified as hostname:port\n", fullname);
       exit(1);
    }
    serv = sep+1;
@@ -583,30 +604,13 @@ void resolve_name(struct addrinfo **out, char* fullname)
 
    res = resolve_split_name(out, host, serv);
    if (res) {
-      fprintf(stderr, "%s `%s'\n", gai_strerror(res), fullname);
+      print_message(msg_config_error, "%s `%s'\n", gai_strerror(res), fullname);
       if (res == EAI_SERVICE)
-         fprintf(stderr, "(Check you have specified all ports)\n");
+         print_message(msg_config_error, "(Check you have specified all ports)\n");
       exit(4);
    }
 }
 
-/* Log to syslog or stderr if foreground */
-void log_message(int type, const char* msg, ...)
-{
-    va_list ap;
-
-    va_start(ap, msg);
-    if (cfg.foreground)
-        vfprintf(stderr, msg, ap);
-    va_end(ap);
-
-    if (do_syslog) {
-        va_start(ap, msg);
-        vsyslog(type, msg, ap);
-        va_end(ap);
-    }
-}
-
 
 /* Fills a connection description; returns 0 on failure */
 int get_connection_desc(struct connection_desc* desc, const struct connection *cnx)
@@ -641,30 +645,6 @@ int get_connection_desc(struct connection_desc* desc, const struct connection *c
     return 1;
 }
 
-/* syslogs who connected to where 
- * desc: string description of the connection. if NULL, log_connection will
- * manage on its own
- * cnx: connection descriptor
- * */
-void log_connection(struct connection_desc* desc, const struct connection *cnx)
-{
-    struct connection_desc d;
-
-    if (cnx->proto->log_level < 1)
-        return;
-
-    if (!desc) {
-        desc = &d;
-        get_connection_desc(desc, cnx);
-    }
-
-    log_message(LOG_INFO, "%s:connection from %s to %s forwarded from %s to %s\n",
-                cnx->proto->name,
-                desc->peer,
-                desc->service,
-                desc->local,
-                desc->target);
-}
 
 void set_proctitle_shovel(struct connection_desc* desc, const struct connection *cnx)
 {
@@ -708,8 +688,7 @@ int check_access_rights(int in_socket, const char* service)
     /* extract peer address */
     res = getnameinfo(&peer.saddr, size, addr_str, sizeof(addr_str), NULL, 0, NI_NUMERICHOST);
     if (res) {
-        if (cfg.verbose)
-            fprintf(stderr, "getnameinfo(NI_NUMERICHOST):%s\n", gai_strerror(res));
+        print_message(msg_system_error, "getnameinfo(NI_NUMERICHOST):%s\n", gai_strerror(res));
         strcpy(addr_str, STRING_UNKNOWN);
     }
     /* extract peer name */
@@ -717,15 +696,12 @@ int check_access_rights(int in_socket, const char* service)
     if (!cfg.numeric) {
         res = getnameinfo(&peer.saddr, size, host, sizeof(host), NULL, 0, NI_NAMEREQD);
         if (res) {
-            if (cfg.verbose)
-                fprintf(stderr, "getnameinfo(NI_NAMEREQD):%s\n", gai_strerror(res));
+            print_message(msg_system_error, "getnameinfo(NI_NAMEREQD):%s\n", gai_strerror(res));
         }
     }
 
     if (!hosts_ctl(service, host, addr_str, STRING_UNKNOWN)) {
-        if (cfg.verbose)
-            fprintf(stderr, "access denied\n");
-        log_message(LOG_INFO, "connection from %s(%s): access denied", host, addr_str);
+        print_message(msg_connections, "connection from %s(%s): access denied", host, addr_str);
         close(in_socket);
         return -1;
     }
@@ -760,35 +736,6 @@ void setup_signals(void)
 
 }
 
-/* Open syslog connection with appropriate banner;
- * banner is made up of basename(bin_name)+"[pid]" */
-void setup_syslog(const char* bin_name) {
-    char *name1, *name2;
-    int res, fn;
-
-    if (!strcmp(cfg.syslog_facility, "none")) {
-        do_syslog = 0;
-        return;
-    }
-
-    name1 = strdup(bin_name);
-    res = asprintf(&name2, "%s[%d]", basename(name1), getpid());
-    CHECK_RES_DIE(res, "asprintf");
-
-    for (fn = 0; facilitynames[fn].c_val != -1; fn++)
-        if (strcmp(facilitynames[fn].c_name, cfg.syslog_facility) == 0)
-            break;
-    if (facilitynames[fn].c_val == -1) {
-        fprintf(stderr, "Unknown facility %s\n", cfg.syslog_facility);
-        exit(1);
-    }
-
-    openlog(name2, LOG_CONS, facilitynames[fn].c_val);
-    free(name1);
-    /* Don't free name2, as openlog(3) uses it (at least in glibc) */
-
-    log_message(LOG_INFO, "%s %s started\n", server_type, VERSION);
-}
 
 /* Ask OS to keep capabilities over a setuid(nonzero) */
 void set_keepcaps(int val) {
@@ -866,16 +813,14 @@ void drop_privileges(const char* user_name, const char* chroot_path)
     if (user_name) {
         pw = getpwnam(user_name);
         if (!pw) {
-            fprintf(stderr, "%s: not found\n", user_name);
+            print_message(msg_config_error, "%s: not found\n", user_name);
             exit(2);
         }
-        if (cfg.verbose)
-            fprintf(stderr, "turning into %s\n", user_name);
+        print_message(msg_config, "turning into %s\n", user_name);
     }
 
     if (chroot_path) {
-        if (cfg.verbose)
-            fprintf(stderr, "chrooting into %s\n", chroot_path);
+        print_message(msg_config, "chrooting into %s\n", chroot_path);
 
         res = chroot(chroot_path);
         CHECK_RES_DIE(res, "chroot");
@@ -905,14 +850,23 @@ void drop_privileges(const char* user_name, const char* chroot_path)
 void write_pid_file(const char* pidfile)
 {
     FILE *f;
+    int res;
 
     f = fopen(pidfile, "w");
     if (!f) {
-        perror(pidfile);
-        exit(3);
+        print_message(msg_system_error, "write_pid_file: %s: %s\n", pidfile, strerror(errno));
+        return;
     }
 
-    fprintf(f, "%d\n", getpid());
-    fclose(f);
-}
+    res = fprintf(f, "%d\n", getpid());
+    if (res < 0) {
+        print_message(msg_system_error, "write_pid_file: fprintf: %s\n", strerror(errno));
+        return;
+    }
 
+    res = fclose(f);
+    if (res == EOF) {
+        print_message(msg_system_error, "write_pid_file: fclose: %s\n", strerror(errno));
+        return;
+    }
+}

common.h

@@ -5,6 +5,7 @@
  * enough for the macros to adapt (http://support.microsoft.com/kb/111855)
  */
 #ifdef __CYGWIN__
+#undef FD_SETSIZE
 #define FD_SETSIZE 4096
 #endif
 
@@ -40,20 +41,20 @@
 
 #define CHECK_RES_DIE(res, str) \
     if (res == -1) {    \
-       fprintf(stderr, "%s:%d:", __FILE__, __LINE__); \
+       print_message(msg_system_error, "%s:%d:", __FILE__, __LINE__); \
        perror(str);     \
        exit(1);         \
     }
 
 #define CHECK_RES_RETURN(res, str, ret) \
     if (res == -1) {                                    \
-        log_message(LOG_CRIT, "%s:%d:%s:%d:%s\n", __FILE__, __LINE__, str, errno, strerror(errno));  \
+        print_message(msg_system_error, "%s:%d:%s:%d:%s\n", __FILE__, __LINE__, str, errno, strerror(errno));  \
         return ret;                                     \
     } 
 
 #define CHECK_ALLOC(a, str) \
     if (!a) { \
-        fprintf(stderr, "%s:%d:", __FILE__, __LINE__); \
+        print_message(msg_system_error, "%s:%d:", __FILE__, __LINE__); \
         perror(str); \
         exit(1); \
     }
@@ -83,9 +84,6 @@ enum connection_state {
     ST_SHOVELING   /* Connexion is established */
 };
 
-/* this is used to pass protocols through the command-line parameter parsing */
-#define PROT_SHIFT 1000  /* protocol options will be 1000, 1001, etc */
-
 /* A 'queue' is composed of a file descriptor (which can be read from or
  * written to), and a queue for deferred write data */
 struct queue {
@@ -95,6 +93,12 @@ struct queue {
     int deferred_data_size;
 };
 
+/* Double linked list for timeout management */
+typedef struct {
+    struct connection* head;
+    struct connection* tail;
+} dl_list;
+
 struct connection {
     int type;           /* SOCK_DGRAM | SOCK_STREAM */
     struct sslhcfg_protocols_item* proto; /* Where to connect to */
@@ -109,13 +113,16 @@ struct connection {
     struct queue q[2];
 
     /* SOCK_DGRAM */
-    struct sockaddr client_addr; /* Contains the remote client address */
+    struct sockaddr_storage client_addr; /* Contains the remote client address */
     socklen_t addrlen;
 
     int local_endpoint; /* Contains the local address */
 
     time_t last_active;
 
+    /* double linked list of timeouts */
+    struct connection *timeout_prev, *timeout_next;
+
     /* We need one local socket for each target server, so we know where to
      * forward server responses */
     int target_sock;  
@@ -160,13 +167,12 @@ void setup_syslog(const char* bin_name);
 void drop_privileges(const char* user_name, const char* chroot_path);
 void set_capabilities(int cap_net_admin);
 void write_pid_file(const char* pidfile);
-void log_message(int type, const char* msg, ...);
 void dump_connection(struct connection *cnx);
 int resolve_split_name(struct addrinfo **out, char* hostname, char* port);
 
 int start_listen_sockets(struct listen_endpoint *sockfd[]);
 
-int defer_write(struct queue *q, void* data, int data_size);
+int defer_write(struct queue *q, void* data, ssize_t data_size);
 int flush_deferred(struct queue *q);
 
 extern struct sslhcfg_item cfg;
@@ -178,4 +184,8 @@ void start_shoveler(int);
 
 void main_loop(struct listen_endpoint *listen_sockets, int num_addr_listen);
 
+/* landlock.c */
+void setup_landlock(void);
+
+
 #endif

config.h.in

@@ -0,0 +1,9 @@
+
+
+#ifndef CONFIG_H
+/* Template for config.h, filled by `configure`. */
+
+/* Landlock sandboxing Linux LSM */
+#undef HAVE_LANDLOCK
+
+#endif

configure.ac

@@ -0,0 +1,9 @@
+
+dnl Use autoconf to generate the `configure` script from this and Makefile.in
+
+AC_INIT
+AC_CONFIG_HEADERS(config.h)
+AC_CONFIG_FILES([Makefile])
+
+AC_CHECK_HEADERS(linux/landlock.h, AC_DEFINE(HAVE_LANDLOCK), [])
+AC_OUTPUT

container-entrypoint.sh

@@ -0,0 +1,97 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL2-or-later
+#
+# Copyright (C) 2023 Olliver Schinagl <oliver@schinagl.nl>
+#
+# A beginning user should be able to docker run image bash (or sh) without
+# needing to learn about --entrypoint
+# https://github.com/docker-library/official-images#consistency
+
+set -eu
+
+bin='sslh'
+
+# run command if it is not starting with a "-" and is an executable in PATH
+if [ "${#}" -le 0 ] || \
+   [ "${1#-}" != "${1}" ] || \
+   [ -d "${1}" ] || \
+   ! command -v "${1}" > '/dev/null' 2>&1; then
+	entrypoint='true'
+fi
+
+unconfigure_iptables() { 
+	echo "Received SIG TERM/INT/KILL. Removing iptables / routing changes"
+
+	set +e # Don't exit if got error
+	set -x
+
+	iptables -t raw -D PREROUTING ! -i lo -d 127.0.0.0/8 -j DROP
+	iptables -t mangle -D POSTROUTING ! -o lo -s 127.0.0.0/8 -j DROP
+
+	iptables -t nat -D OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+	iptables -t mangle -D OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	ip rule del fwmark 0x1 lookup 100
+	ip route del local 0.0.0.0/0 dev lo table 100
+
+
+	if [ $(cat /proc/sys/net/ipv6/conf/all/disable_ipv6) -eq 0 ]; then
+		ip6tables -t raw -D PREROUTING ! -i lo -d ::1/128 -j DROP
+		ip6tables -t mangle -D POSTROUTING ! -o lo -s ::1/128 -j DROP
+		ip6tables -t nat -D OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+		ip6tables -t mangle -D OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+		ip -6 rule del fwmark 0x1 lookup 100
+		ip -6 route del local ::/0 dev lo table 100
+	fi
+		
+	set -e
+	set +x
+}
+
+configure_iptables() {
+	echo "Configuring iptables and routing..."
+
+	set +e # Don't exit if got error
+	set -x
+	
+	iptables -t raw -A PREROUTING ! -i lo -d 127.0.0.0/8 -j DROP
+	iptables -t mangle -A POSTROUTING ! -o lo -s 127.0.0.0/8 -j DROP
+
+	iptables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN  -j CONNMARK --set-xmark 0x01/0x0f
+	iptables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	ip rule add fwmark 0x1 lookup 100
+	ip route add local 0.0.0.0/0 dev lo table 100
+
+	if [ $(cat /proc/sys/net/ipv6/conf/all/disable_ipv6) -eq 0 ]; then
+		ip6tables -t raw -A PREROUTING ! -i lo -d ::1/128 -j DROP
+		ip6tables -t mangle -A POSTROUTING ! -o lo -s ::1/128 -j DROP
+		ip6tables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+		ip6tables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+		ip -6 rule add fwmark 0x1 lookup 100
+		ip -6 route add local ::/0 dev lo table 100
+	fi
+	
+	set -e
+	set +x
+}
+
+for _args in "${@}" ; do
+	if [ "${_args:-}" = '--transparent' ] ; then
+		echo '--transparent flag is set'
+		configure_iptables
+		trap unconfigure_iptables TERM INT KILL
+		break
+	fi
+done
+
+# Drop privileges and run as sslh user
+sslh_cmd="${entrypoint:+${bin}} ${@}"
+echo "Executing with user 'sslh': ${sslh_cmd}"
+
+exec su - sslh -c "${sslh_cmd}" &
+wait "${!}"
+
+exit 0

doc/FAQ.md

@@ -7,7 +7,7 @@ doesn't work, report how what was suggested here went.
 It's also worth reading [how to ask
 questions](http://www.catb.org/~esr/faqs/smart-questions.html)
 before posting on the mailing list or opening an issue in
-Github.
+GitHub.
 
 Getting more info
 =================

doc/INSTALL.md

@@ -1,3 +1,13 @@
+Pre-built binaries
+==================
+
+Docker images of `master` and of the tagged versions are
+available directly from [Github](https://github.com/yrutschle/sslh/pkgs/container/sslh).
+
+Windows binaries for Cygwin are graciously produced by
+nono303 on his [repository](https://github.com/nono303/sslh).
+
+
 Compile and install
 ===================
 
@@ -6,115 +16,130 @@ Dependencies
 
 `sslh` uses:
 
-* [libconfig](http://www.hyperrealm.com/libconfig/). For
-  Debian this is contained in package `libconfig8-dev`. You
-can compile with or without it using USELIBCONFIG in the
-Makefile.
+* [libconfig](http://www.hyperrealm.com/libconfig/).
+  For Debian this is contained in package `libconfig-dev`.
+  You can compile with or without it using USELIBCONFIG in the Makefile.
 
 * [libwrap](http://packages.debian.org/source/unstable/tcp-wrappers).
-    For Debian, this is contained in packages
-`libwrap0-dev`. You
-can compile with or without it using USELIBWRAP in the
-Makefile.
+  For Debian, this is contained in packages `libwrap0-dev`.
+  You can compile with or without it using USELIBWRAP in the Makefile.
 
-* [libsystemd](http://packages.debian.org/source/unstable/libsystemd-dev), in package `libsystemd-dev`.  You
-can compile with or without it using USESYSTEMD in the
-Makefile.
+* [libsystemd](http://packages.debian.org/source/unstable/libsystemd-dev), in package `libsystemd-dev`.
+  You can compile with or without it using USESYSTEMD in the Makefile.
 
-* [libcap](http://packages.debian.org/source/unstable/libcap-dev), in package `libcap-dev`. You can compile with or without it using USELIBCAP in the Makefile
+* [libcap](http://packages.debian.org/source/unstable/libcap-dev), in package `libcap-dev`.
+  You can compile with or without it using USELIBCAP in the Makefile
 
-* libbsd, to enable to change the process name (as shown in
-  `ps`, so each forked process shows what protocol and what
-  connection it is serving),
-which requires `libbsd` at runtime, and `libbsd-dev` at
-compile-time.
+* libbsd, to enable to change the process name (as shown in `ps`,
+  so each forked process shows what protocol and what connection it is serving),
+  which requires `libbsd` at runtime, and `libbsd-dev` at compile-time.
+
+* libpcre2, in package `libpcre2-dev`.
+  You can compile with or without it using ENABLE_REGEX in the Makefile.
+
+* libev-dev, in package `libev-dev`.
+  If you build a binary specifically and do not build `sslh-ev`, you don't need this.
 
 
 For OpenSUSE, these are contained in packages libconfig9 and
 libconfig-dev in repository
 <http://download.opensuse.org/repositories/multimedia:/libs/openSUSE_12.1/>
 
-For Fedora, you'll need packages `libconfig` and
-`libconfig-devel`:
+For Fedora, you'll need packages `libconfig` and `libconfig-devel`:
 
-	yum install libconfig libconfig-devel
+    yum install libconfig libconfig-devel
 
-If you want to rebuild `sslh-conf.c` (after a `make
-distclean` for example), you will also need to add
-[conf2struct](https://www.rutschle.net/tech/conf2struct/README.html)
+If you want to rebuild `sslh-conf.c` (after a `make distclean` for example),
+you will also need to add [conf2struct](https://www.rutschle.net/tech/conf2struct/README.html)
 (v1.5) to your path.
 
+The test scripts are written in Perl, and will require
+`IO::Socket::INET6` (`libio-socket-inet6-perl` in Debian).
+
+
 Compilation
 -----------
 
 After this, the Makefile should work:
 
-	make install
+    make install
 
-There are a couple of configuration options at the beginning
-of the Makefile: 
+There are a couple of configuration options at the beginning of the Makefile: 
 
-* `USELIBWRAP` compiles support for host access control (see
-  `hosts_access(3)`), you will need `libwrap` headers and
-  library to compile (`libwrap0-dev` in Debian).
+* `USELIBWRAP` compiles support for host access control (see `hosts_access(3)`),
+  you will need `libwrap` headers and library to compile (`libwrap0-dev` in Debian).
 
-* `USELIBCONFIG` compiles support for the configuration
-  file. You will need `libconfig` headers to compile
-  (`libconfig8-dev` in Debian).
+* `USELIBCONFIG` compiles support for the configuration file.
+  You will need `libconfig` headers to compile (`libconfig8-dev` in Debian).
 
-*  `USESYSTEMD` compiles support for using systemd socket activation.
-   You will need `systemd` headers to compile (`systemd-devel` in Fedora).
+* `USESYSTEMD` compiles support for using systemd socket activation.
+  You will need `systemd` headers to compile (`systemd-devel` in Fedora).
+
+* `USELIBBSD` compiles support for updating the process name (as shown by `ps`).
+
+
+Generating the configuration parser
+-----------------------------------
+
+The configuration file and command line parser is generated by `conf2struct`,
+from `sslhconf.cfg`, which generates `sslh-conf.c` and `sslh-conf.h`.
+The resulting files are included in the source
+so `sslh` can be built without `conf2struct` installed.
+
+Further, to prevent build issues,
+`sslh-conf.[ch]` has no dependency to `sslhconf.cfg` in the Makefile.
+In the event of adding configuration settings,
+they need to be regenerated using `make c2s`.
 
-* `USELIBBSD` compiles support for updating the process name (as shown
-  by `ps`).
 
 Binaries
 --------
 
-The Makefile produces two different executables: `sslh-fork`
-and `sslh-select`:
+The Makefile produces three different executables:
+`sslh-fork`, `sslh-select` and `sslh-ev`:
 
 * `sslh-fork` forks a new process for each incoming connection.
-It is well-tested and very reliable, but incurs the overhead
-of many processes.  
-If you are going to use `sslh` for a "small" setup (less than
-a dozen ssh connections and a low-traffic https server) then
-`sslh-fork` is probably more suited for you. 
+  It is well-tested and very reliable, but incurs the overhead of many processes.  
+  If you are going to use `sslh` for a "small" setup
+  (less than a dozen ssh connections and a low-traffic https server)
+  then `sslh-fork` is probably more suited for you.
 
-* `sslh-select` uses only one thread, which monitors all connections
-at once. It is more recent and less tested, but only incurs a 16
-byte overhead per connection. Also, if it stops, you'll lose all
-connections, which means you can't upgrade it remotely.  
-If you are going to use `sslh` on a "medium" setup (a few thousand ssh
-connections, and another few thousand ssl connections),
-`sslh-select` will be better.
+* `sslh-select` uses only one thread, which monitors all connections at once.
+  It only incurs a 16 byte overhead per connection.
+  Also, if it stops, you'll lose all connections,
+  which means you can't upgrade it remotely.
+  If you are going to use `sslh` on a "medium" setup (a few hundreds of connections),
+  or if you are on a system where forking is expensive (e.g. Windows),
+  `sslh-select` will be better.
 
-If you have a very large site (tens of thousands of connections),
-you'll need a vapourware version that would use libevent or
-something like that.
+* `sslh-ev` is similar to `sslh-select`, but uses `libev` as a backend.
+  This allows using specific kernel APIs that
+  allow to manage thousands of connections concurrently.
 
 
 Installation
 ------------
 
 * In general:
-
-		make
-		cp sslh-fork /usr/local/sbin/sslh
-		cp basic.cfg /etc/sslh.cfg
-                vi /etc/sslh.cfg
-
+  ```sh
+  ./configure
+  make
+  cp sslh-fork /usr/local/sbin/sslh
+  cp basic.cfg /etc/sslh.cfg
+  vi /etc/sslh.cfg
+  ```
 * For Debian:
-
-		cp scripts/etc.init.d.sslh /etc/init.d/sslh
-	
+  ```sh
+  cp scripts/etc.init.d.sslh /etc/init.d/sslh
+  ```
 * For CentOS:
-
-		cp scripts/etc.rc.d.init.d.sslh.centos /etc/rc.d/init.d/sslh
-
+  ```sh
+  cp scripts/etc.rc.d.init.d.sslh.centos /etc/rc.d/init.d/sslh
+  ```
 
 You might need to create links in /etc/rc<x>.d so that the server
 start automatically at boot-up, e.g. under Debian:
-
-	update-rc.d sslh defaults
+```sh
+update-rc.d sslh defaults
+```
 

doc/README.MacOSX

@@ -33,7 +33,7 @@ with launchctl or simply reboot.
 		<string>0.0.0.0:443</string>
 		<string>--ssh</string>
 		<string>localhost:22</string>
-		<string>--ssl</string>
+		<string>--tls</string>
 		<string>localhost:443</string>
 	</array>
 	<key>QueueDirectories</key>

doc/README.Windows.md

@@ -0,0 +1,72 @@
+It is possible to run `sslh` on Windows. The `fork` model
+should be avoided as it is very inefficient on Windows, but
+`sslh-select` and `sslh-ev` both work with good performance
+(prefer the latter, however).
+
+
+The following script downloads the latest cygwin, the latest version of sslh, and then compiles and copies the binaries with dependancies to an output folder.
+
+It may be needed to correct it from time to time, but it works. I use it in a virtual machine.
+Just retrieve WGET.EXE from https://eternallybored.org/misc/wget/ or git binaries.
+
+Copy the 3 files
+
+	GO.cmd
+	wget.exe
+	compile.sh
+	
+to C root folder, then execute **GO.cmd** with administrative rights.
+
+with **GO.cmd**
+
+	@ECHO OFF
+	CD /D "%~dp0"
+	
+	NET SESSION >NUL 2>&1
+	IF %ERRORLEVEL% NEQ 0 (
+	    ECHO Permission denied. This script must be run as an Administrator.
+	    ECHO:
+	    GOTO FIN
+	) ELSE (
+	    ECHO Running as Administrator.
+	    TIMEOUT /T 2 >NUL
+		wget --no-check-certificate https://www.cygwin.com/setup-x86_64.exe
+		IF NOT EXIST setup-x86_64.exe GOTO FIN
+		MKDIR C:\Z
+		setup-x86_64.exe -l C:\Z -s ftp://ftp.funet.fi/pub/mirrors/sourceware.org/pub/cygwin/ -q -P make -P git -P gcc-g++ -P autoconf -P automake -P libtool -P libpcre-devel -P libpcre2-devel -P bison -P libev-devel
+		MKDIR C:\cygwin64\home\user
+	COPY COMPILE.SH C:\cygwin64\home\user
+			START C:\cygwin64\bin\mintty.exe /bin/bash --login -i ~/compile.sh
+		START EXPLORER C:\zzSORTIE
+	)
+	:FIN
+	PAUSE
+	EXIT
+
+
+and **compile.sh**
+
+	# SAVE FILE TO UNIX FORMAT
+	# COPY IT IN C cygwin64 home user
+	git clone https://github.com/hyperrealm/libconfig.git
+	cd libconfig
+	autoreconf -fi
+	./configure
+	make
+	make install
+	cd ..
+	cp /usr/local/lib/libconfig.* /usr/lib
+	git clone https://github.com/yrutschle/sslh.git
+	cd sslh
+	make
+	cd ..
+	mkdir /cygdrive/c/zzSORTIE
+	cp ./sslh/sslh*.exe /cygdrive/c/zzSORTIE
+	cp /usr/local/bin/cygconfig-11.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygwin1.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygpcreposix-0.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygpcre-1.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygev-4.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygpcre2-8-0.dll /cygdrive/c/zzSORTIE
+
+This method was contributed by lerenardo on [github](https://github.com/yrutschle/sslh/issues/196#issuecomment-1692805639).

doc/config.md

@@ -65,13 +65,13 @@ Configuration goes like this on the server side, using `stunnel3`:
   * `-f` for foreground/debugging
   * `-p` for specifying the key and certificate
   * `-d` for specifying which interface and port
-	we're listening to for incoming connexions
+	we're listening to for incoming connections
   * `-l` summons `sslh` in inetd mode.
 
 * sslh options:
   * `-i` for inetd mode
-  * `--http` to forward HTTP connexions to port 80,
-	and SSH connexions to port 22.
+  * `--http` to forward HTTP connections to port 80,
+	and SSH connections to port 22.
 
 Capabilities support
 --------------------
@@ -92,165 +92,15 @@ to the executable:
 
 	sudo setcap cap_net_bind_service,cap_net_raw+pe sslh-select
 
-Then you can run sslh-select as an unpriviledged user, e.g.:
+Then you can run sslh-select as an unprivileged user, e.g.:
 
 	sslh-select -p myname:443 --ssh localhost:22 --tls localhost:443
 
 Transparent proxy support
 -------------------------
 
-On Linux and FreeBSD you can use the `--transparent` option to
-request transparent proxying. This means services behind `sslh`
-(Apache, `sshd` and so on) will see the external IP and ports
-as if the external world connected directly to them. This
-simplifies IP-based access control (or makes it possible at
-all).
-
-You can refer to Sean Warn'ѕ [tutorial](tproxy.md) for a
-different set-up which enables transparent proxying between
-two different machines. The following may only work if
-`sslh` and the final servers are on the same machine.
-
-Note that getting this to work is very tricky and
-detail-dependant: depending on whether the target server and
-sslh are on the same machine, different machines, or
-different dockers, and tool versions, all seem to change the
-required network configuration somewhat. If it doesn't work,
-it's almost certain that the problem is not linked to `sslh`
-but to the network setup that surrounds it.
-
-Linux:
-
-`sslh` needs extended rights to perform this: you'll need to
-give it `CAP_NET_RAW` capabilities (see appropriate chapter)
-or run it as root (but don't do that).
-
-The firewalling tables also need to be adjusted as follows.
-I don't think it is possible to have `httpd` and `sslh` both listen to 443 in
-this scheme -- let me know if you manage that:
-
-	# Set route_localnet = 1 on all interfaces so that ssl can use "localhost" as destination
-	sysctl -w net.ipv4.conf.default.route_localnet=1
-	sysctl -w net.ipv4.conf.all.route_localnet=1
-
-	# DROP martian packets as they would have been if route_localnet was zero
-	# Note: packets not leaving the server aren't affected by this, thus sslh will still work
-	iptables -t raw -A PREROUTING ! -i lo -d 127.0.0.0/8 -j DROP
-	iptables -t mangle -A POSTROUTING ! -o lo -s 127.0.0.0/8 -j DROP
-
-	# Mark all connections made by ssl for special treatment (here sslh is run as user "sslh")
-	iptables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
-
-	# Outgoing packets that should go to sslh instead have to be rerouted, so mark them accordingly (copying over the connection mark)
-	iptables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
-
-	# Configure routing for those marked packets
-	ip rule add fwmark 0x1 lookup 100
-	ip route add local 0.0.0.0/0 dev lo table 100
-
-Tranparent proxying with IPv6 is similarly set up as follows:
-
-	# Set route_localnet = 1 on all interfaces so that ssl can use "localhost" as destination
-	# Not sure if this is needed for ipv6 though
-	sysctl -w net.ipv4.conf.default.route_localnet=1
-	sysctl -w net.ipv4.conf.all.route_localnet=1
-
-	# DROP martian packets as they would have been if route_localnet was zero
-	# Note: packets not leaving the server aren't affected by this, thus sslh will still work
-	ip6tables -t raw -A PREROUTING ! -i lo -d ::1/128 -j DROP
-	ip6tables -t mangle -A POSTROUTING ! -o lo -s ::1/128 -j DROP
-
-	# Mark all connections made by ssl for special treatment (here sslh is run as user "sslh")
-	ip6tables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
-
-	# Outgoing packets that should go to sslh instead have to be rerouted, so mark them accordingly (copying over the connection mark)
-	ip6tables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
-
-	# Configure routing for those marked packets
-	ip -6 rule add fwmark 0x1 lookup 100
-	ip -6 route add local ::/0 dev lo table 100
-
-Explanation:
-To be able to use `localhost` as destination in your sslh config along with transparent proxying
-you have to allow routing of loopback addresses as done above.
-This is something you usually should not do (see [this stackoverflow post](https://serverfault.com/questions/656279/how-to-force-linux-to-accept-packet-with-loopback-ip/656484#656484))
-The two `DROP` iptables rules emulate the behaviour of `route_localnet` set to off (with one small difference:
-allowing the reroute-check to happen after the fwmark is set on packets destined for sslh).
-See [this diagram](https://upload.wikimedia.org/wikipedia/commons/3/37/Netfilter-packet-flow.svg) for a good visualisation
-showing how packets will traverse the iptables chains.
-
-Note:
-You have to run `sslh` as dedicated user (in this example the user is also named `sslh`), to not mess up with your normal networking.
-These rules will allow you to connect directly to ssh on port
-22 (or to any other service behind sslh) as well as through sslh on port 443.
-
-Also remember that iptables configuration and ip routes and 
-rules won't be necessarily persisted after you reboot. Make 
-sure to save them properly. For example in CentOS7, you would 
-do `iptables-save > /etc/sysconfig/iptables`, and add both 
-`ip` commands to your `/etc/rc.local`.
-
-FreeBSD:
-
-Given you have no firewall defined yet, you can use the following configuration
-to have ipfw properly redirect traffic back to sslh
-
-	/etc/rc.conf
-	firewall_enable="YES"
-	firewall_type="open"
-	firewall_logif="YES"
-	firewall_coscripts="/etc/ipfw/sslh.rules"
-
-
-/etc/ipfw/sslh.rules
-
-	#! /bin/sh
-
-	# ssl
-	ipfw add 20000 fwd 192.0.2.1,443 log tcp from 192.0.2.1 8443 to any out
-	ipfw add 20010 fwd 2001:db8::1,443 log tcp from 2001:db8::1 8443 to any out
-
-	# ssh
-	ipfw add 20100 fwd 192.0.2.1,443 log tcp from 192.0.2.1 8022 to any out
-	ipfw add 20110 fwd 2001:db8::1,443 log tcp from 2001:db8::1 8022 to any out
-
-	# xmpp
-	ipfw add 20200 fwd 192.0.2.1,443 log tcp from 192.0.2.1 5222 to any out
-	ipfw add 20210 fwd 2001:db8::1,443 log tcp from 2001:db8::1 5222 to any out
-
-	# openvpn (running on other internal system)
-	ipfw add 20300 fwd 192.0.2.1,443 log tcp from 198.51.100.7 1194 to any out
-	ipfw add 20310 fwd 2001:db8::1,443 log tcp from 2001:db8:1::7 1194 to any out
-
-General notes:
-
-
-This will only work if `sslh` does not use any loopback
-addresses (no `127.0.0.1` or `localhost`), you'll need to use
-explicit IP addresses (or names):
-
-	sslh --listen 192.168.0.1:443 --ssh 192.168.0.1:22 --tls 192.168.0.1:4443
-
-This will not work:
-
-	sslh --listen 192.168.0.1:443 --ssh 127.0.0.1:22 --tls 127.0.0.1:4443
-    
-Transparent proxying means the target server sees the real
-origin address, so it means if the client connects using
-IPv6, the server must also support IPv6. It is easy to
-support both IPv4 and IPv6 by configuring the server
-accordingly, and setting `sslh` to connect to a name that
-resolves to both IPv4 and IPv6, e.g.:
-
-        sslh --transparent --listen <extaddr>:443 --ssh insideaddr:22
-
-        /etc/hosts:
-        192.168.0.1  insideaddr
-        201::::2     insideaddr
-
-Upon incoming IPv6 connection, `sslh` will first try to
-connect to the IPv4 address (which will fail), then connect
-to the IPv6 address.
+Transparent proxying is described in its own
+[document](tproxy.md).
 
 Systemd Socket Activation
 -------------------------
@@ -313,7 +163,7 @@ This parses the /etc/sslh.cfg (or /etc/sslh/sslh.cfg file if that exists
 instead) configuration file and dynamically generates a socket file to use.
 
 This will also merge with any sslh.socket.d drop in configuration but will be 
-overriden by a /etc/systemd/system/sslh.socket file.
+overridden by a /etc/systemd/system/sslh.socket file.
 
 To use the generator place it in /usr/lib/systemd/system-generators and then
 call systemctl daemon-reload after any changes to /etc/sslh.cfg to generate 
@@ -335,13 +185,15 @@ UDP
 ---
 
 `sslh` can perform demultiplexing on UDP packets as well.
-This only works with `sslh-select` (it is not possible to
+This does not work with `sslh-fork` (it is not possible to
 support UDP with a forking model). Specify a listening
 address and target protocols with `is_udp: true`. `sslh`
 will wait for incoming UDP packets, run the probes in the
 usual fashion, and forward packets to the appropriate
 target. `sslh` will then remember the association between
 remote host to target server for 60 seconds by default,
-which can be overriden with `udp_timeout`. This allows to
+which can be overridden with `udp_timeout`. This allows to
 process both single-datagram protocols such as DNS, and
 connection-based protocols such as QUIC.
+
+An example for supporting QUIC is shown in `example.cfg`.

doc/scenarios-for-simple-transparent-proxy.md

@@ -0,0 +1,49 @@
+# Three Scenarios for the simple transparent proxy setup #
+
+![Simple Transparent Proxy Examples](./sslh-examples-v3.png)
+
+## Introduction ##
+The first example is the configuration, which was described in the previousd document. I omitted the loopback interface "lo" in those diagrams, trying not no overload the picture. 
+The connections have two different endings, showing the direction of the opening connection (SYN flag) and the answer connection (SYN-ACK flags). This is important, as the traffic in the transparent proxy setup flows somewhat unexpected.
+
+## Example 1 ##
+The first example shows the setup, which is described in the [previous document](./simple_transparent_proxy.md). You see the Client connecting to sslh (red connection). When sslh accepts this connection, the SYN-ACK packet is send back to the client, which sends the first data packet(s) together with the ACK for the SYN-ACK. So the bidirectional tcp connection is fully open.
+Sslh opens now the blue connection to sshd and needs for that elevation rights, as it uses the clients IP address as its own address for opening this connection. Now things are becoming complicated: Sshd send back the first packet with SYN-ACK flags (green line), addressed to the clients IP (dotted line). As already described, that would go wrong, so our routing trick makes this packet beeing deflected back to sslh, so this tcp connection is also opened. But we have here now an asymetric behaviour, that the read and write pathes of the tcp connection are going different routes.
+The sslh process shuffles now all the bytes coming from sshd from the green line to the red line, vice versa for the packets from the client.
+
+## Example 2 ##
+In this example sshd is running on another server. No matter, if this is docker, kvm, virtualbox or another physical host, connected with an ethernet cable. Here we need no dummy interface, so we need another way, to configure our routing deflection.  The principle is the same: We need to force packets coming back from sshd going to sslh and not directly back to the client.
+In this case its your decision, where those rules will be tied in, options are:
+
+* the startscript of sslh
+* the docker or kvm configuration
+* the configuration of the outgoing interface
+
+Its two lines you need:
+```
+ip rule add from SSHD_ADDRESS/32 table sslh
+ip route add local 0.0.0.0/0 dev lo table sslh
+```
+On the sshd host, we need no additional rules, as all traffic is coming back to our sslh host, because this is in this setting the default gateway.  The only thing, we need to do: Assign a unique IP address only for sshd and all other services, you wish to hide behind sslh and host on this device.
+
+There are two ways, how you can add multiple ip addresses to one device. The new _**ip addr add**_ supports multiple add statements to one and the same interface name. So you can just duplicate the interface stancas in the _**/etc/network/interfaces**_ configuration. The problem with this method is, that some older managment tools, like ifconfig are unable to show the additional addresses. So when you are used to some older tools, you may configure sub-interfaces like eth0:1.
+However my recommendation is, migrate to new tools, get used to it, as old tools don't show you the whole configuration!
+
+## Example 3 ##
+This is now the extended version of the previous example. The target host has another path back to the client, as there is a default route to another interface. Now we need **TWO** routing deflections, one on the sslh host, like in scenario 2, and one on the sshd target host.
+The routing setup on the target host looks like:
+* Add an routing table name for the deflection table in _**/etc/iproute2/rt_tables**_
+* Find a location, where you will hook the two routing rules in
+```
+ip rule add from SSHD_ADDRESS/32 table sslh_routeback
+ip route add default via SERVER1_ETH1_IP dev eth0 table sslh_routeback
+
+```
+This is setting up a default route for all traffic, originating from the ip address sshd (or any other service) is using, back to the host, hosting sslh. On that host, those packets will be deflected again with the same rule from scenario 2.
+
+## Modifications ##
+Now you can think about many modifications, but the tools will be the same, for all other thinkable scenarios. You must always make sure, that packets from foreign hosts, will find their way back to the sslh host. So if the chain consists of three or four servers, all need the deflection rules. 
+
+## Important Finding On Routing ##
+When I went ahead and wrote in my first drawings the warning, that the kernel in scenario 2 and 3 needs to have forwarding in place, I finally tested, that this is not true. **Both scenarios are working without kernel forwarding beeing activated!**
+The background:  The deflecting routing table cames into the game, before the kernel has to made the decision, that packets with non local ip addresses in source and destination must be forwarded. After the routing rule deliveres the packet to sslh and sslh rewrites the source ip, the packet is treated as local, and can pass the system.

doc/simple_transparent_proxy.md

@@ -0,0 +1,133 @@
+# Transparent Proxy Configuration Using IP Routing#
+This documentation is another explanation of the transparent proxy with the goal, beeing secure and minimalistic. Besides this documentation will explain, how and why this configuration works.
+The explanation will only describe the connection to sshd, so the target sshd can be replace with any other target service, sslh supports.
+
+## Introduction in the data flow ##
+This chapter can be skipped, if you just like to configure things fast.
+This chapter is a little excurse to the dataflow. First point of all is something, which you will unfortunately not see in the nice routing diagrams for iptables or netfilter-tables (nft) like: [Iptables at wikipedia](https://upload.wikimedia.org/wikipedia/commons/thumb/3/37/Netfilter-packet-flow.svg/2560px-Netfilter-packet-flow.svg.png), [Netfilter Flow](https://wiki.nftables.org/wiki-nftables/index.php/Netfilter_hooks#Netfilter_hooks_into_Linux_networking_packet_flows).
+
+Packets from local application talking to other local applications are routed through the loopback-interface. They leave postrouting to lo and reentering from there prerouting, without passing ingress/egress.
+This has nothing to do with the "**route_localnet = 1**" trick, which only makes, that the the local ip range 10.0.0.0/8 gets routed!
+As you can read in many articles, this is nothing you should do, as you may bring your system at risk, because it allows to leak packets from outside to applications, which feel themselves secure, by using those unroutable addresses.
+#### A Simple Simulation ####
+You can prove this behaviour with a simple test:
+```
+# In one terminal start socat as a local echo server
+# this is simulating sshd
+
+socat TCP4-LISTEN:2000,bind=SERVER_IP,fork EXEC:cat
+
+# In the next terminal start another instance of socat,
+# simulating sslh
+
+socat TCP-LISTEN:3000,bind=SERVER_IP,fork TCP:SERVER_IP:2000
+
+# In another terminal you can watch the traffic on lo
+
+tcpdump -i lo port 2000
+
+# In the last terminal talk to the echo server
+telnet SERVER_IP 2000
+```
+You will see your traffic on lo, but not on eth0, if you retry the tcpdump there.
+
+If you setup sslh as non transparent proxy, it will just work, as what we have seen.  
+
+#### Going Transparent ####
+
+In case of transparent proxy however, sslh uses some tricks, to reuse the clients IP on its outgoing interface to sshd. It opens the interface in raw mode, so it either needs to be started as root and drop privileges after binding, or you will need to give some capabilities to the sslh binary (cap_net_bind_service,cap_net_raw+ep), if you will start it as restricted user.
+In this setup we continue, with dropping priviledges.
+
+Doing so, you can send packets to the sshd, listening on another interface, but, the answer packets from sshd will get routed back to the client. This however will not work, as the client would refuse those packets, because they don't belong to a tcp session, the client opened. In most cases those packets would even not reach the client, as source ip addresses from private address space, will be blocked by most internet routers and connection providers.
+
+So its mandatory, to use some tricks, to get those packets back to sslh. All configurations, I have seen so far, are using two components for that. They bind sshd to lo, and than they introduce some firewall rules, to mark packets, originating from the sshd port on lo, so that those packets can be routed in a next step -based on that marking- back to sslh.
+
+##### Drawbacks From Using loopback #####
+This idea has some serious drawbacks: First, you need to allow routing of the local address space, 127.0.0.0/8, with kernel configurations. Search for the string "net.ipv4.conf.default.route_localnet" and you will find lot of articles, why you should not do this.
+By allowing this, you need additional firewall rules, dropping martian packets, which otherwise would get routed to the internet from other applications, running on lo, not aware, that their traffic could be routed.  You need further firewall rules, blocking incoming packets to loopback addresses, as otherwise some applications (especially udp) could be the goal of some bad traffic.
+
+##### Using A Dedicated Interface #####
+So this configuration makes use of a own interface, just for the services, where sslh should hide the traffic for. We use a interface of the dummy kernel module, which was designed just for this case.  It is an interface, beeing there, having no cable connection or whatsever, but applications can bind to it. We assign to this interface just a /32 private address, as this interface is not part of any network.
+
+Doing so, we can avoid all the hassle with marking certain packets, coming from the single applications, sslh has to hide, as we now just route ALL traffic from this specific interface by its ip to sslh.
+We need one routing rule and one routing table, this covers as many targets sslh will serve on this interface, without adding additional rules for adding apache, openvpn and others.
+
+We need no firewall rules, preventing martians, as this single routing rule will deadroute all traffic from this interface, if sslh is not catching it up.
+
+We only need firewall protection for this specific ip address, when we have activated ip forwarding on that system.  If the system is no router and needs no forwarding, there is no protection needed.
+
+## Finally The Configuration ##
+
+As described, we need as a first step a dedicated interface, just for the services, sslh should hide. Its possible, to generate individual interfaces for different configurations, however, that makes things again more complex and has no advantages seen so far.
+
+### Named Routing Table ###
+As we configure the needed routing rules in the interface configuration, we need to define a name for the sslh routing table first.
+Using named routing tables helps, understanding the routing configuration, as a name indicates, why this routing table is configured.
+To do so go to  _**/etc/iproute2/rt_tables**_ and add a line
+
+```
+ 111     sslh
+```
+
+### Dummy Interface ###
+Now we configure our dedicatet interface.
+In the file _**/etc/network/interfaces**_, we place this entry:
+```
+auto dummy0
+iface dummy0 inet static
+    address 192.168.255.254/32
+    pre-up modprobe dummy
+    ## Attention! with kernels, not automatically creating a dummy0
+    ## interface after module loading the following line should be:
+    ## pre-up modprobe dummy; if [ ! -e /sys/class/net/dummy0 ]; then ip link add dummy0 type dummy ; fi
+    post-up ip rule add from 192.168.255.254 table sslh
+    post-up ip route add local 0.0.0.0/0 dev dummy0 table sslh
+    pre-down ip route del local 0.0.0.0/0 dev dummy0 table sslh
+    pre-down ip rule del from 192.168.255.254 table sslh
+```
+As long, as your system has no other interfaces with private address-space, or is routing such addresses, you can continue with the given example. Otherwise you need to select a conflict free address.
+If you are updating a older current configuration, make sure, that you have no longer insecure localnet routing in place:
+```
+ sysctl  net.ipv4.conf.default.route_localnet  
+ sysctl net.ipv4.conf.all.route_localnet
+```
+should both report "0"!
+
+
+### Explanation Of The Routing Rules ###
+The two routing rules in the dummy0 interface configuration are the key for this configuration.
+
+The first line is an routing rule entry, routing everything coming from the dummy0 ip source address to a special routing table _**sslh**_. 
+
+The next line generates this table implicitly, by inserting a single rule, routing everything from that ip address to dummy0.
+
+Opposite to other firewall based configurations, we have those rules now tied to the dummy0 device, dedicated to the hidden services.
+When this interface comes up, the routing rules are making sure, that no martian packets can leave the system, by some processes using this IP address. When the interface goes down, we delete those rules.
+Also the startup script needs lo longer special treatment for the transparent mode.
+
+
+#### SSLH Default Configuration ####
+And finally you need to configute _**/etc/default/sslh**_ with the right settings for all the services, sslh should work for.
+```
+DAEMON_OPTS="--user sslh --listen SERVER_IP:443 --transparent  \
+             --ssh 192.168.255.254:22 --tls 192.168.255.254:443 \
+             --pidfile /var/run/sslh/sslh.pid"
+```
+
+#### Systemd #### 
+This setup is now startup agnostic. As we don't need special treatment in the startup script, the sysV based init scripts will just work, like the systemd scripts. Nothing needs to be modified, when going transparent.
+
+#### Remote Setups ####
+This concept can also be adapted for several setups, where the sshd (or any other target service) is running in a container, kvm-virtual machine, etc.
+Precondition is, that the target system is the next hop and uses the sslh-hosting system as default gateway. In addition you need to bind an additional ip-address, solely used for sshd on the corresponding interface.
+Than you can adapt the routing rule, routing traffic coming back from this ip to the sslh-routing-table.
+Its also possible, to forward to an next hop system, which has its own default gateway back, bypassing the sslh-host.
+In this case, you need to add a special route back to the sslh host, for all traffic with the sshd source ip address. This can be done similar to the two rules described above:
+```
+  # first define a name for the table in /etc/iproute2/rt_tables e.g. sslh-routeback
+  ip rule add from IPADRESS-OF-SERVIE table sslh-routeback
+  ip route add default via IPADDRESS-OF_SSLH-HOST dev eth0 table sslh-routeback
+```
+The details are depending on your network settings. Als long, as the forward chain to the hidden service passes systems under your control, you can add backroutes on each system in that route. Precondition: The used ip address produces no conflict on those systems.
+
+[I added a second document](./scenarios-for-simple-transparent-proxy.md), describing three possible scenarios in detail. Those three scenarios should cover all setups related to transparent proxying. 

doc/tproxy.md

@@ -1,17 +1,177 @@
-Transparent Proxy to Two Hosts
-==============================
+# Transparent proxy using packet marking
+
+Before reading further, make sure you try to set up
+transparent proxying using [IP routing](doc/simple_transparent_proxy.md).
+It is conceptually easier to understand, cleaner, and more
+portable.
+
+Using this method is very tricky and
+detail-dependant: depending on whether the target server and
+sslh are on the same machine, different machines, or
+different dockers, and tool versions, all seem to change the
+required network configuration somewhat. If it doesn't work,
+it's almost certain that the problem is not linked to `sslh`
+but to the network setup that surrounds it. If in trouble,
+it might be worth trying to set up the network rules
+with a simpler server than `sslh`, such as
+[`socat`](http://www.dest-unreach.org/socat/)
+
+
+Users have tried to do at least the following:
+
+  * `sslh` and the target servers run on the same host (see [below](#transparent-proxy-to-one-host))
+  * `sslh` runs on a host, and the target servers run on LXC or dockers running on the same host. No known working setup.
+  * `sslh` runs on a host, and the target servers run on different hosts on the same local network(see [below](#transparent-proxy-to-two-hosts))
+  * `sslh` runs on a host, and the target servers run on a different host on a different network (there is a [usecase](https://github.com/yrutschle/sslh/issues/295) for this). No known working setup, and it's unclear it is possible.
+
+
+## Transparent proxy to one host
+
+### Linux
+
+`sslh` needs extended rights to perform this: you'll need to
+give it `CAP_NET_RAW` capabilities (see appropriate chapter)
+or run it as root (but don't do that).
+
+The firewalling tables also need to be adjusted as follows.
+I don't think it is possible to have `httpd` and `sslh` both listen to 443 in
+this scheme -- let me know if you manage that:
+
+	# Set route_localnet = 1 on all interfaces so that ssl can use "localhost" as destination
+	sysctl -w net.ipv4.conf.default.route_localnet=1
+	sysctl -w net.ipv4.conf.all.route_localnet=1
+
+	# DROP martian packets as they would have been if route_localnet was zero
+	# Note: packets not leaving the server aren't affected by this, thus sslh will still work
+	iptables -t raw -A PREROUTING ! -i lo -d 127.0.0.0/8 -j DROP
+	iptables -t mangle -A POSTROUTING ! -o lo -s 127.0.0.0/8 -j DROP
+
+	# Mark all connections made by ssl for special treatment (here sslh is run as user "sslh")
+	iptables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+
+	# Outgoing packets that should go to sslh instead have to be rerouted, so mark them accordingly (copying over the connection mark)
+	iptables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	# Configure routing for those marked packets
+	ip rule add fwmark 0x1 lookup 100
+	ip route add local 0.0.0.0/0 dev lo table 100
+
+Transparent proxying with IPv6 is similarly set up as follows:
+
+	# Set route_localnet = 1 on all interfaces so that ssl can use "localhost" as destination
+	# Not sure if this is needed for ipv6 though
+	sysctl -w net.ipv4.conf.default.route_localnet=1
+	sysctl -w net.ipv4.conf.all.route_localnet=1
+
+	# DROP martian packets as they would have been if route_localnet was zero
+	# Note: packets not leaving the server aren't affected by this, thus sslh will still work
+	ip6tables -t raw -A PREROUTING ! -i lo -d ::1/128 -j DROP
+	ip6tables -t mangle -A POSTROUTING ! -o lo -s ::1/128 -j DROP
+
+	# Mark all connections made by ssl for special treatment (here sslh is run as user "sslh")
+	ip6tables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+
+	# Outgoing packets that should go to sslh instead have to be rerouted, so mark them accordingly (copying over the connection mark)
+	ip6tables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	# Configure routing for those marked packets
+	ip -6 rule add fwmark 0x1 lookup 100
+	ip -6 route add local ::/0 dev lo table 100
+
+Explanation:
+To be able to use `localhost` as destination in your sslh config along with transparent proxying
+you have to allow routing of loopback addresses as done above.
+This is something you usually should not do (see [this stackoverflow post](https://serverfault.com/questions/656279/how-to-force-linux-to-accept-packet-with-loopback-ip/656484#656484))
+The two `DROP` iptables rules emulate the behaviour of `route_localnet` set to off (with one small difference:
+allowing the reroute-check to happen after the fwmark is set on packets destined for sslh).
+See [this diagram](https://upload.wikimedia.org/wikipedia/commons/3/37/Netfilter-packet-flow.svg) for a good visualisation
+showing how packets will traverse the iptables chains.
+
+Note:
+You have to run `sslh` as dedicated user (in this example the user is also named `sslh`), to not mess up with your normal networking.
+These rules will allow you to connect directly to ssh on port
+22 (or to any other service behind sslh) as well as through sslh on port 443.
+
+Also remember that iptables configuration and ip routes and 
+rules won't be necessarily persisted after you reboot. Make 
+sure to save them properly. For example in CentOS7, you would 
+do `iptables-save > /etc/sysconfig/iptables`, and add both 
+`ip` commands to your `/etc/rc.local`.
+
+### FreeBSD
+
+Given you have no firewall defined yet, you can use the following configuration
+to have ipfw properly redirect traffic back to sslh
+
+	/etc/rc.conf
+	firewall_enable="YES"
+	firewall_type="open"
+	firewall_logif="YES"
+	firewall_coscripts="/etc/ipfw/sslh.rules"
+
+
+/etc/ipfw/sslh.rules
+
+	#! /bin/sh
+
+	# ssl
+	ipfw add 20000 fwd 192.0.2.1,443 log tcp from 192.0.2.1 8443 to any out
+	ipfw add 20010 fwd 2001:db8::1,443 log tcp from 2001:db8::1 8443 to any out
+
+	# ssh
+	ipfw add 20100 fwd 192.0.2.1,443 log tcp from 192.0.2.1 8022 to any out
+	ipfw add 20110 fwd 2001:db8::1,443 log tcp from 2001:db8::1 8022 to any out
+
+	# xmpp
+	ipfw add 20200 fwd 192.0.2.1,443 log tcp from 192.0.2.1 5222 to any out
+	ipfw add 20210 fwd 2001:db8::1,443 log tcp from 2001:db8::1 5222 to any out
+
+	# openvpn (running on other internal system)
+	ipfw add 20300 fwd 192.0.2.1,443 log tcp from 198.51.100.7 1194 to any out
+	ipfw add 20310 fwd 2001:db8::1,443 log tcp from 2001:db8:1::7 1194 to any out
+
+General notes:
+
+
+This will only work if `sslh` does not use any loopback
+addresses (no `127.0.0.1` or `localhost`), you'll need to use
+explicit IP addresses (or names):
+
+	sslh --listen 192.168.0.1:443 --ssh 192.168.0.1:22 --tls 192.168.0.1:4443
+
+This will not work:
+
+	sslh --listen 192.168.0.1:443 --ssh 127.0.0.1:22 --tls 127.0.0.1:4443
+    
+Transparent proxying means the target server sees the real
+origin address, so it means if the client connects using
+IPv6, the server must also support IPv6. It is easy to
+support both IPv4 and IPv6 by configuring the server
+accordingly, and setting `sslh` to connect to a name that
+resolves to both IPv4 and IPv6, e.g.:
+
+        sslh --transparent --listen <extaddr>:443 --ssh insideaddr:22
+
+        /etc/hosts:
+        192.168.0.1  insideaddr
+        201::::2     insideaddr
+
+Upon incoming IPv6 connection, `sslh` will first try to
+connect to the IPv4 address (which will fail), then connect
+to the IPv6 address.
+
+
+## Transparent Proxy to Two Hosts
 
 Tutorial by Sean Warner.  19 June 2019 20:35
 
-Aim
----
+### Aim
 
 * Show that `sslh` can transparently proxy requests from the internet to services on two separate hosts that are both on the same LAN.
 * The IP address of the client initiating the request is what the destination should see… and not the IP address of the host that `sslh` is running on, which is what happens when `sslh` is not running in transparent mode.
 * The solution here only works for my very specific use-case but hopefully others can adapt it to suits their needs.
 
-Overview of my Network
-----------------------
+### Overview of my Network
 
 Two Raspberry Pis on my home LAN:
 * Pi A: 192.168.1.124 – `sslh` (Port 4433), Apache2 web server for https (port 443), `stunnel` (port 4480) to decrypt ssh traffic and forward to SSH server (also on Pi A at Port 1022)
@@ -20,8 +180,7 @@ Two Raspberry Pis on my home LAN:
 
 ![Architecture](tproxy.svg)
 
-`sslh` build
-------------
+### `sslh` build
  
 `sslh` Version: sslh v1.19c-2-gf451cc8-dirty.
 
@@ -47,8 +206,7 @@ MAN=sslh.8.gz          # man page name
 # itself
 ```
  
-systemd setup
--------------
+### systemd setup
 
 Create an sslh systemd service file...
 ```
@@ -83,8 +241,7 @@ Start it again to test…
 # systemctl start sslh
 ```
  
-Configure `sslh`
-----------------
+### Configure `sslh`
 
 First stop `sslh` then open the config file and replace with below, save and start `sslh` again
 ```
@@ -123,8 +280,7 @@ protocols:
 );
 ```
  
-Configure `stunnel`
--------------------
+### Configure `stunnel`
 
 First stop `stunnel` then open the config file and replace with below, save and start `stunnel` again
 ```
@@ -151,8 +307,7 @@ connect = 192.168.1.124:1022
 TIMEOUTclose  = 0
 ```
  
-Configure iptables for Pi A
---------------------------
+### Configure iptables for Pi A
 
 The `_add.sh` script creates the rules, the `_rm.sh` script removes the rules.
 They will be lost if you reboot but there are ways to make them load again on start-up..
@@ -194,8 +349,7 @@ Now run the "add" script on Pi A!
 # piA_tproxy_rm.sh
 ```
  
-Configure iptables for Pi B
---------------------------
+## Configure iptables for Pi B
 
 ```
 # nano /usr/local/sbin/piB_tproxy_add.sh
@@ -235,8 +389,8 @@ Now run the "add" script on Pi B!
 # piB_tproxy_rm.sh
 ```
  
-Testing
--------
+### Testing
+
 * Getting to sshd on PiA
 
 I did this test using 4G from my phone (outside the LAN)

echo_test.cfg

@@ -0,0 +1,12 @@
+
+# TODO: c2s does not warn if udp: 1 (instead of 'true')
+
+udp: true;
+
+prefix: "hello";
+
+listen: "localhost:9000";
+
+listen-host: "localhost";
+listen-port: "9000";
+

echosrv-conf.c

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Fri Aug 13 18:03:20 2021. 
+ * on Sat Apr 30 09:55:03 2022. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2021  Yves Rutschle
@@ -365,7 +365,7 @@ static int clcpy(config_type type, void* target, const void* cl_arg)
     return 0;
 }
 
-/* Copy the value of a string argument to arbitary memory
+/* Copy the value of a string argument to arbitrary memory
 * location that must be large enough, converting on the way
 * (i.e. CFG_INT gets atoi() and so on) */
 /* 0: success
@@ -862,7 +862,7 @@ static int set_target_fields(void* target_addr, struct compound_cl_arg* arg, con
             if (pmatch[pmatch_cnt].rm_so == -1) {
                 /* This should not happen as regexec() did
                 * match before, unless there is a
-                * discrepency between the regex and the
+                * discrepancy between the regex and the
                 * number of backreferences */
                 return 0;
             }
@@ -1155,7 +1155,7 @@ static void scalar_to_string(char** strp, config_setting_t* s)
 
 /* Typesets all the settings in a configuration as a
 * newly-allocated string. The string management is caller's
-* responsability. 
+* responsibility. 
 * Returns the number of scalars in the configuration */
 static int cfg_as_string(config_setting_t* parent, const char* path, char** strp)
 {

echosrv-conf.h

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Fri Aug 13 18:03:20 2021. 
+ * on Sat Apr 30 09:55:03 2022. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2021  Yves Rutschle

echosrv.c

@@ -1,6 +1,6 @@
 /* echosrv: a simple line echo server with optional prefix adding.
  *
- * echsrv --listen localhost6:1234 --prefix "ssl: "
+ * echosrv --listen localhost6:1234 --prefix "ssl: "
  *
  * This will bind to 1234, and echo every line pre-pending "ssl: ". This is
  * used for testing: we create several such servers with different prefixes,
@@ -62,9 +62,10 @@ void check_res_dump(int res, struct addrinfo *addr, char* syscall)
 
 void start_echo(int fd)
 {
-    int res;
+    ssize_t res;
     char buffer[1 << 20];
-    int ret, prefix_len;
+    ssize_t ret;
+    size_t prefix_len;
     int first = 1;
 
     prefix_len = strlen(cfg.prefix);
@@ -100,7 +101,10 @@ void tcp_echo(struct listen_endpoint* listen_socket)
 {
     while (1) {
         int in_socket = accept(listen_socket->socketfd, 0, 0);
-        CHECK_RES_DIE(in_socket, "accept");
+        if (in_socket == -1) {
+            perror("tcp_echo:accept");
+            exit(1);
+        }
 
         if (!fork())
         {
@@ -109,6 +113,7 @@ void tcp_echo(struct listen_endpoint* listen_socket)
             exit(0);
         }
         close(in_socket);
+        waitpid(-1, NULL, WNOHANG);
     }
 }
 
@@ -147,7 +152,7 @@ void udp_echo(struct listen_endpoint* listen_socket)
 
     while (1) {
         addrlen = sizeof(src_addr);
-        size_t len = recvfrom(listen_socket->socketfd, 
+        ssize_t len = recvfrom(listen_socket->socketfd,
                            data + prefix_len,
                            sizeof(data) - prefix_len,
                            0,
@@ -158,11 +163,11 @@ void udp_echo(struct listen_endpoint* listen_socket)
             perror("recvfrom");
         }
         *(data + prefix_len + len) = 0;
-        fprintf(stderr, "%ld: %s\n", len, data + prefix_len);
+        fprintf(stderr, "%zd %s\n", len, data + prefix_len);
 
         print_udp_xchange(listen_socket->socketfd, &src_addr, addrlen);
 
-        int res = sendto(listen_socket->socketfd,
+        ssize_t res = sendto(listen_socket->socketfd,
                          data,
                          len + prefix_len,
                          0,

echoѕrv-conf.h

@@ -0,0 +1,109 @@
+/* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
+ * on Sat Nov  7 09:19:26 2020. 
+
+# conf2struct: generate libconf parsers that read to structs
+# Copyright (C) 2018-2019  Yves Rutschle
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+#    this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+*/
+ 
+#ifndef C2S_SSLHCFG_H
+#define C2S_SSLHCFG_H
+#ifdef LIBCONFIG
+#    include <libconfig.h>
+#endif
+
+
+#include "probe.h"
+#include  <sys/types.h>
+#include  <sys/socket.h>
+#include  <netdb.h>
+
+struct sslhcfg_listen_item {
+	char*	host;
+	char*	port;
+	int	keepalive;
+};
+
+struct sslhcfg_protocols_item {
+	char*	name;
+	char*	host;
+	char*	port;
+	int	service_is_present;
+	char*	service;
+	int	fork;
+	int	tfo_ok;
+	int	log_level;
+	int	keepalive;
+	size_t	sni_hostnames_len;
+	char** sni_hostnames;
+	size_t	alpn_protocols_len;
+	char** alpn_protocols;
+	size_t	regex_patterns_len;
+	char** regex_patterns;
+	int	minlength_is_present;
+	int	minlength;
+	T_PROBE*	probe;
+	struct addrinfo*	saddr;
+	void*	data;
+};
+
+struct sslhcfg_item {
+	char*	prefix;
+	int	verbose;
+	int	foreground;
+	int	inetd;
+	int	numeric;
+	int	transparent;
+	int	timeout;
+	int	user_is_present;
+	char*	user;
+	int	pidfile_is_present;
+	char*	pidfile;
+	int	chroot_is_present;
+	char*	chroot;
+	char*	syslog_facility;
+	char*	on_timeout;
+	size_t	listen_len;
+	struct sslhcfg_listen_item* listen;
+	size_t	protocols_len;
+	struct sslhcfg_protocols_item* protocols;
+};
+
+int sslhcfg_parse_file(
+        const char* filename,
+        struct sslhcfg_item* sslhcfg, 
+        const char** errmsg);
+
+void sslhcfg_fprint(
+    FILE* out,
+    struct sslhcfg_item *sslhcfg,
+    int depth);
+
+int sslhcfg_cl_parse(
+    int argc,
+    char* argv[],
+    struct sslhcfg_item *sslhcfg);
+
+#endif

example.cfg

@@ -3,7 +3,6 @@
 # not be used as a starting point for a working
 # configuration. Instead use basic.cfg.
 
-verbose: 0;
 foreground: true;
 inetd: false;
 numeric: false;
@@ -13,6 +12,30 @@ user: "nobody";
 pidfile: "/var/run/sslh.pid";
 chroot: "/var/empty";
 
+# Logging configuration
+# Value: 1: stdout; 2: syslog; 3: stdout+syslog; 4: logfile; ...; 7: all
+# Defaults are indicated here, and should be sensible. Generally, you want *-error
+# to be always enabled, to know if something is going wrong.
+verbose-config: 0; #  print configuration at startup
+verbose-config-error: 3;  # print configuration errors
+verbose-connections: 3; # trace established incoming address to forward address
+verbose-connections-error: 3; # connection errors
+verbose-connections-try: 0; # connection attempts towards targets
+verbose-fd: 0; # file descriptor activity, open/close/whatnot
+verbose-packets: 0; # hexdump packets on which probing is done
+verbose-probe-info: 0; # what's happening during the probe process
+verbose-probe-error: 3; # failures and problems during probing
+verbose-system-error: 3; # system call problem, i.e.  malloc, fork, failing
+verbose-int-error: 3; # internal errors, the kind that should never happen
+
+
+# Specify a path to the logfile.
+#logfile: "/var/log/sslh.log"
+
+# Specify the number of concurrent UDP connection that can
+# be managed (default 1024)
+udp_max_connections: 16;
+
 # Specify which syslog facility to use (names for your
 # system are usually defined in /usr/include/*/sys/syslog.h
 # or equivalent)
@@ -44,6 +67,8 @@ listen:
 #   fork: Should a new process be forked for this protocol?
 #         (only useful for sslh-select)
 #   tfo_ok: Set to true if the server supports TCP FAST OPEN
+#   resolve_on_forward: Set to true if server address should be resolved on
+#         (every) newly incoming connection (again)
 #   transparent: Set to true to proxy this protocol
 #         transparently (server sees the remote client IP
 #         address). Same as the global option, but per-protocol
@@ -53,7 +78,9 @@ listen:
 # connect to the first that matches.)
 #
 #       tls:
-#               sni_hostnames:  list of FQDN for that target
+#               sni_hostnames:  list of FQDN for that target. Each name can
+#               include wildcard following glob(7) rules.
+
 #               alpn_protocols: list of ALPN protocols for that target, see:
 #               https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol-ids
 #
@@ -98,7 +125,7 @@ protocols:
                       udp_timeout: 20;  # Time after which the "connection" is forgotten
                       regex_patterns: [ "hello" ]; },
 # Forward Teamspeak3 (Voice only)
-     { name: "regex"; host: "localhost"; is_udp: true; port: "9987"; regex_patterns: [ "TS3INIT1" ]; },
+     { name: "teamspeak"; host: "localhost"; is_udp: true; port: "9987"; },
 # Forward IETF QUIC-50 ("Q050" -> "\x51\x30\x35\x30")
 # Remember that the regex needs to be adjusted for every supported QUIC version.
      { name: "regex"; host: "localhost"; is_udp: true; port: "4433"; regex_patterns: [ "\x51\x30\x35\x30" ]; },

gap.c

@@ -31,11 +31,6 @@
 #include "gap.h"
 
 
-typedef struct gap_array {
-    int len; /* Number of elements in array */
-    void** array;
-} gap_array;
-
 /* Allocate one page-worth of elements */
 static int gap_len_alloc(int elem_size)
 {
@@ -53,7 +48,10 @@ gap_array* gap_init(int len)
     gap->len = gap_len_alloc(elem_size);
     if (gap->len < len) gap->len = len;
     gap->array = malloc(gap->len * elem_size);
-    if (!gap->array) return NULL;
+    if (!gap->array) {
+        free(gap);
+        return NULL;
+    }
 
     for (int i = 0; i < gap->len; i++)
         gap->array[i] = NULL;
@@ -61,12 +59,7 @@ gap_array* gap_init(int len)
     return gap;
 }
 
-void* gap_get(gap_array* gap, int index)
-{
-    return gap->array[index];
-}
-
-static int gap_extend(gap_array* gap)
+int gap_extend(gap_array* gap)
 {
     int elem_size = sizeof(gap->array[0]);
     int new_length = gap->len + gap_len_alloc(elem_size);
@@ -84,17 +77,6 @@ static int gap_extend(gap_array* gap)
     return 0;
 }
 
-int gap_set(gap_array* gap, int index, void* ptr)
-{
-    while (index >= gap->len) {
-        int res = gap_extend(gap);
-        if (res == -1) return -1;
-    }
-
-    gap->array[index] = ptr;
-    return 0;
-}
-
 void gap_destroy(gap_array* gap) 
 {
     free(gap->array);
@@ -120,7 +102,7 @@ int gap_remove_ptr(gap_array* gap, void* ptr, int len)
     else
         return -1;
 
-    for (i = start; i < len; i++) {
+    for (i = start; i < len - 1; i++) {
         gap->array[i] = gap->array[i+1];
     }
 

gap.h

@@ -4,10 +4,40 @@
 typedef struct gap_array gap_array;
 
 gap_array* gap_init(int len);
-void* gap_get(gap_array* gap, int index);
-int gap_set(gap_array* gap, int index, void* ptr);
+static void* gap_get(gap_array* gap, int index);
+static int gap_set(gap_array* gap, int index, void* ptr);
 void gap_destroy(gap_array* gap);
 
 int gap_remove_ptr(gap_array* gap, void* ptr, int len);
 
+/* Private declarations to allow inlining.
+ * Don't assume my implementation. */
+typedef struct gap_array {
+    int len; /* Number of elements in array */
+    void** array;
+} gap_array;
+
+int gap_extend(gap_array* gap);
+
+static inline int __attribute__((unused)) gap_set(gap_array* gap, int index, void* ptr)
+{
+    while (index >= gap->len) {
+        int res = gap_extend(gap);
+        if (res == -1) return -1;
+    }
+
+    gap->array[index] = ptr;
+    return 0;
+}
+
+static inline void* __attribute__((unused)) gap_get(gap_array* gap, int index)
+{
+    /* sslh-ev routinely reads before it writes. It's not clear if it should be
+     * its job to check the length (and add a gap_getlen()), or if it should be
+     * gap_get()'s job. This will do for now */
+    if (index >= gap->len) return NULL;
+
+    return gap->array[index];
+}
+
 #endif

genver.sh

@@ -10,14 +10,14 @@ fi
 if [ ! -d .git ] || ! `(git status | grep -q "On branch") 2> /dev/null`; then
         # If we don't have git, we can't work out what
         # version this is. It must have been downloaded as a
-        # zip file. 
-        
+        # zip file.
+
         # If downloaded from the release page, the directory
         # has the version number.
         release=`pwd | sed s/.*sslh-// | grep "[[:digit:]]"`
-        
+
         if [ "x$release" = "x" ]; then
-            # If downloaded from the head, Github creates the
+            # If downloaded from the head, GitHub creates the
             # zip file with all files dated from the last
             # change: use the Makefile's modification time as a
             # release number
@@ -28,7 +28,7 @@ fi
 if [ -d .git ] && head=`git rev-parse --verify HEAD 2>/dev/null`; then
 	# generate the version info based on the tag
 	release=`(git describe --tags || git --describe || git describe --all --long) \
-		2>/dev/null | tr -d '\n'`
+		2>/dev/null | tr -s '/' '-' | tr -d '\n'`
 
 	# Are there uncommitted changes?
 	git update-index --refresh --unmerged > /dev/null

hash.c

@@ -0,0 +1,224 @@
+/* 
+ * a fixed-sized hash
+ *
+# Copyright (C) 2022  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+#
+# */
+
+
+/*  * The hash is open-addressing, linear search, robin-hood insertion, with 
+ * backward shift deletion. References:
+ * https://codecapsule.com/2013/11/11/robin-hood-hashing/
+ * https://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/
+ * This means items are reordered upon insertion and deletion, and the hash
+ * is well-ordered at all times with no tombstones.
+ *
+ * Each pointer is either:
+ * - to a connection struct
+ * - FREE (NULL) if not allocated
+ *
+ * */
+
+#include <stdlib.h>
+#include <stddef.h>
+
+#include "gap.h"
+
+typedef void* hash_item;
+#include "hash.h"
+
+static void* const FREE = NULL;
+
+struct hash {
+    int hash_size;      /* Max number of items in the hash */
+    int item_cnt;       /* Number of items in the hash */
+    gap_array* data;
+
+    hash_make_key_fn hash_make_key;
+    hash_cmp_item_fn cmp_item;
+};
+
+typedef struct hash hash;
+
+
+static int hash_make_key(hash* h, hash_item item)
+{
+    return h->hash_make_key(item) % h->hash_size;
+}
+
+
+hash* hash_init(int hash_size, hash_make_key_fn make_key, hash_cmp_item_fn cmp_item)
+{
+    hash* h = malloc(sizeof(*h));
+    if (!h) return NULL;
+
+    h->hash_size = hash_size;
+    h->item_cnt = 0;
+    h->data = gap_init(hash_size);
+    h->hash_make_key = make_key;
+    h->cmp_item = cmp_item;
+
+    return h;
+}
+
+/* Return the index following i in h */
+static int hash_next_index(hash* h, int i)
+{
+    return (i + 1) % h->hash_size;
+}
+
+/* Returns the index in h of specified address, -1 if not found 
+ * item is an item object that must return the target wanted index and for
+ * which comparison with the searched object will succeed.
+ * */
+static int hash_find_index(hash* h, hash_item item)
+{
+    hash_item cnx;
+    int index = hash_make_key(h, item);
+    int cnt = 0;
+
+    cnx = gap_get(h->data, index);
+#ifdef DEBUG
+    fprintf(stderr, "searching %d\n", index);
+#endif
+    while (cnx != FREE) {
+        if (cnt++ > h->hash_size) return -1;
+
+        if (!h->cmp_item(cnx, item))
+            break;
+
+        index = hash_next_index(h, index);
+        cnx = gap_get(h->data, index);
+#ifdef DEBUG
+        fprintf(stderr, "searching %d\n", index);
+#endif
+    } 
+    if (cnx == FREE) return -1;
+    return index;
+}
+
+hash_item hash_find(hash* h, hash_item item)
+{
+    int index = hash_find_index(h, item);
+    if (index == -1) return NULL;
+    hash_item out = gap_get(h->data, index);
+    return out;
+}
+
+
+/* Returns DIB: distance to initial bucket */
+static int distance(int current_index, hash* h, hash_item item)
+{
+    int wanted_index = hash_make_key(h, item);
+    if (wanted_index <= current_index)
+        return current_index - wanted_index;
+    else
+        return current_index - wanted_index + h->hash_size;
+}
+
+
+int hash_insert(hash* h, hash_item new)
+{
+    int bubble_wanted_index = hash_make_key(h, new);
+    int index = bubble_wanted_index;
+    gap_array* hash = h->data;
+
+    if (h->item_cnt == h->hash_size)
+        return -1;
+
+    hash_item curr_item = gap_get(hash, index);
+    while (curr_item) {
+        if (distance(index, h, curr_item) < distance(index, h, new)) {
+            gap_set(h->data, index, new);
+#if DEBUG
+            fprintf(stderr, "intermediate insert [%s] at %d\n", &new->client_addr, index);
+#endif
+            new = curr_item;
+        }
+
+        index = hash_next_index(h, index);
+        curr_item = gap_get(hash, index);
+    }
+
+#if DEBUG
+    fprintf(stderr, "final insert at %d\n", index);
+#endif
+    gap_set(hash, index, new);
+    h->item_cnt++;
+
+    return 0;
+}
+
+/* Remove cnx from the hash */
+int hash_remove(hash* h, hash_item item)
+{
+    gap_array* hash = h->data;
+
+    int index = hash_find_index(h, item);
+    if (index == -1) return -1; /* Tried to remove something that isn't there */
+
+    while (1) {
+        int next_index = hash_next_index(h, index);
+        hash_item next = gap_get(h->data, next_index);
+        if ((next == FREE) || (distance(next_index, h, next) == 0)) {
+            h->item_cnt--;
+            gap_set(hash, index, FREE);
+            return 0;
+        }
+
+        gap_set(hash, index, next);
+
+        index = hash_next_index(h, index);;
+    }
+    return 0;
+}
+
+#if HASH_TESTING
+#include <stdio.h>
+#include <string.h>
+#define STR_LENGTH 16
+struct hash_item {
+    int wanted_index;
+    char str[STR_LENGTH];
+};
+void hash_dump(hash* h, char* filename)
+{
+    char str[STR_LENGTH];
+    FILE* out = fopen(filename, "w");
+
+    if (!out) {
+        perror(filename);
+        exit(1);
+    }
+    
+    fprintf(out, "<hash elem=%d>\n", h->item_cnt);
+    for (int i = 0; i < h->hash_size; i++) {
+        hash_item item = gap_get(h->data, i);
+        int idx = 0;
+
+        memset(str, 0, STR_LENGTH);
+        if (item) {
+            idx = hash_make_key(h, item);
+            memcpy(str, ((struct hash_item*)item)->str, STR_LENGTH);
+        }
+        fprintf(out, "\t%d:%d:%s\n", i, idx, str);
+    }
+    fprintf(out, "</hash>\n");
+    fclose(out);
+}
+#endif

hash.h

@@ -0,0 +1,28 @@
+#ifndef HASH_H
+#define HASH_H
+
+/* You will need to typedef a pointer type to hash_item before including this
+ * .h */
+
+typedef struct hash hash;
+
+/* Function that returns a key (index) for a given item. The key must be always
+ * the same for an item. It doesn't need to be bounded (hash.c masks it for you) */
+typedef int (*hash_make_key_fn)(hash_item item);
+
+/* Function that compares two items: returns 0 if they are the same */
+typedef int (*hash_cmp_item_fn)(hash_item item1, hash_item item2);
+
+hash* hash_init(int hash_size, hash_make_key_fn make_key, hash_cmp_item_fn cmp_item);
+
+int hash_insert(hash* h, hash_item new);
+int hash_remove(hash* h, hash_item item);
+
+/* Returns the hash item that matches specification (meaning the
+ * comparison function returns true for cmp(x, item), or NULL if not found */
+hash_item hash_find(hash* h, hash_item item);
+
+
+void hash_dump(hash* h, char* filename); /* For development only */
+
+#endif

hashtest/Makefile

@@ -0,0 +1,7 @@
+
+CFLAGS=-DHASH_TESTING -O2 -Wall
+OBJ=../hash.o ../gap.o htest.o
+
+htest: $(OBJ)
+	$(CC) -o htest $(OBJ)
+

hashtest/delete.tst

@@ -0,0 +1,8 @@
+# Basic delete
+a 10 aa
+a 10 ab
+a 10 ac
+a 20 ba
+a 21 bb
+
+d 21 bb

hashtest/delete.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:ab
+	12:10:ac
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:20:ba
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_at_end.tst

@@ -0,0 +1,9 @@
+# Delete inside a block with nothing after
+
+a 10 aa
+a 10 ab
+a 12 ac
+a 13 ad
+a 14 ae
+
+d 14 ae

hashtest/delete_at_end.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:ab
+	12:12:ac
+	13:13:ad
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_below_floor.tst

@@ -0,0 +1,9 @@
+# wrap-around and delete below floor
+a 2 ba
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+a 2 bb
+
+d 30 ab

hashtest/delete_below_floor.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=5>
+	0:30:ad
+	1:0:
+	2:2:ba
+	3:2:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ac
+</hash>

hashtest/delete_discont.tst

@@ -0,0 +1,10 @@
+# delete in a discontinuous block
+
+a 10 aa
+a 11 ab
+a 12 ac
+a 14 ad
+a 10 bc
+
+d 11 ab
+

hashtest/delete_discont.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:bc
+	12:12:ac
+	13:0:
+	14:14:ad
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_empty.tst

@@ -0,0 +1,11 @@
+# Delete an unexisting element. And on an empty hash
+
+a 10 aa
+
+d 10 ab
+d 12 bc
+
+# Empty for real
+d 10 aa
+
+d 10 aa

hashtest/delete_empty.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=0>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_full.tst

@@ -0,0 +1,39 @@
+# delete on a full hash
+
+# First, fill the hash :-)
+
+a 0 aa
+a 1 ab
+a 2 ac
+a 3 ad
+a 4 ae
+a 5 af
+a 6 ag 
+a 7 ah
+a 8 ai
+a 9 af
+a 10 ba
+a 11 bb
+a 12 bc
+a 13 bd
+a 14 be 
+a 15 bf
+a 16 bg
+a 17 bh
+a 18 bi
+a 19 bj
+a 20 ca
+a 21 cb
+a 22 cd
+a 23 ce
+a 24 cf
+a 25 cg
+a 26 ch
+a 27 ci
+a 28 cj
+a 29 ck
+a 30 da
+a 31 db
+
+
+d 21 cb

hashtest/delete_full.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=31>
+	0:0:aa
+	1:1:ab
+	2:2:ac
+	3:3:ad
+	4:4:ae
+	5:5:af
+	6:6:ag
+	7:7:ah
+	8:8:ai
+	9:9:af
+	10:10:ba
+	11:11:bb
+	12:12:bc
+	13:13:bd
+	14:14:be
+	15:15:bf
+	16:16:bg
+	17:17:bh
+	18:18:bi
+	19:19:bj
+	20:20:ca
+	21:0:
+	22:22:cd
+	23:23:ce
+	24:24:cf
+	25:25:cg
+	26:26:ch
+	27:27:ci
+	28:28:cj
+	29:29:ck
+	30:30:da
+	31:31:db
+</hash>

hashtest/delete_middle.tst

@@ -0,0 +1,10 @@
+# Delete inside a block with something discontinuous
+
+a 10 aa
+a 10 ab
+a 12 ac
+a 13 ad
+a 14 ae
+
+# ab shifts, ac and next doesn't
+d 10 aa

hashtest/delete_middle.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:ab
+	11:0:
+	12:12:ac
+	13:13:ad
+	14:14:ae
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_wrap.tst

@@ -0,0 +1,8 @@
+# Basic delete when wrapping, between wrap and floor
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ba
+a 30 bb
+
+d 30 ac

hashtest/delete_wrap.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=4>
+	0:30:ba
+	1:30:bb
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/delete_wrap_at_end.tst

@@ -0,0 +1,10 @@
+# Delete inside a block with wrapping, with something after
+
+a 30 aa
+a 30 ab
+a 30 ac
+a 1 ad
+a 3 ae
+
+# shift ad but not ae
+d 14 ae

hashtest/delete_wrap_at_end.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=5>
+	0:30:ac
+	1:1:ad
+	2:0:
+	3:3:ae
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/delete_wrap_below_floor.tst

@@ -0,0 +1,8 @@
+# delete before wrap
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+
+# shift ac and ad
+d 30 ab

hashtest/delete_wrap_below_floor.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=3>
+	0:30:ad
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ac
+</hash>

hashtest/delete_wrap_discont.tst

@@ -0,0 +1,11 @@
+# Delete with wrapping in discontinuous group
+
+a 30 aa
+a 30 ab
+a 30 ac
+a 31 ad
+a 2 ba
+a 3 bb
+
+# shift ac and ad but not ba and bb
+d 30 ab

hashtest/delete_wrap_discont.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=5>
+	0:31:ad
+	1:0:
+	2:2:ba
+	3:3:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ac
+</hash>

hashtest/htest.c

@@ -0,0 +1,109 @@
+/* Wee testing program from the hash code:
+ * htest <script> <dump>
+ *
+ * scripts are a list of operations:
+ * a $index $string
+ * => add an element at specified index
+ * d $index $string
+ * => remove an element
+ * s $index $string
+ * => prints the actual element index, if it's there
+ *
+ * The hash is dumped to the dump file at each iteration.
+ */
+
+
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+
+/* tests have been written for a hash that holds 32 items */
+#define HASH_SIZE 32
+
+#define STR_LENGTH 16
+struct hash_item {
+    int wanted_index;
+    char str[STR_LENGTH];
+};
+
+typedef struct hash_item* hash_item;
+
+#include "../hash.h"
+
+
+
+static int cmp_item(hash_item item1, hash_item item2)
+{
+    return strcmp(item1->str, item2->str);
+}
+
+
+static int hash_make_key(hash_item item)
+{
+    return item->wanted_index;
+}
+
+
+static void htest_next_key(FILE* f, char* action, int* key, char str[STR_LENGTH])
+{
+
+    int res = 0;
+    while ((res != 3) && (res != EOF))
+        res = fscanf(f, "%c %d %s\n", action, key, str);
+    if (res == EOF) exit(0);
+}
+
+int main(int argc, char* argv[])
+{
+    hash* h = hash_init(HASH_SIZE, &hash_make_key, &cmp_item);
+    char action;
+    hash_item item;
+    int line = 0;
+    FILE* f;
+
+    if (argc != 3) {
+        fprintf(stderr, "Usage: htest <script file> <dump file>\n");
+        exit(1);
+    }
+    char* script_file = argv[1];
+    char* dump_file = argv[2];
+    f = fopen(argv[1], "r");
+    if (!f) {
+        perror(script_file);
+        exit(1);
+    }
+
+    while (1) {
+        item= malloc(sizeof(*item));
+        action = ' ';
+
+        line++;
+        htest_next_key(f, &action, &item->wanted_index, item->str);
+        fprintf(stderr, "action %d: %c %d %s\n", line, action, item->wanted_index, item->str);
+
+        switch (action) {
+        case 'a': /* add */
+            fprintf(stderr, "inserting [%s] at %d\n", item->str, item->wanted_index);
+            hash_insert(h, item);
+            break;
+
+        case 'd': /* del */
+            fprintf(stderr, "removing [%s] at %d\n", item->str, item->wanted_index);
+            hash_remove(h, item);
+            break;
+
+        case 's': /* search */
+            fprintf(stderr, "searching\n");
+            struct hash_item* found = hash_find(h, item);
+            fprintf(stderr, "searching %d[%s]: %p\n", item->wanted_index, item->str, found);
+            break;
+
+        case 'q': /* quit */
+            exit(1);
+        }
+        hash_dump(h, dump_file);
+    }
+    return 0;
+}

hashtest/insert.tst

@@ -0,0 +1,6 @@
+# Basic insertions
+a 10 aa
+a 10 ab
+a 10 ac
+a 20 ba
+a 21 bb

hashtest/insert.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=5>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:ab
+	12:10:ac
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:20:ba
+	21:21:bb
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/insert_discont.tst

@@ -0,0 +1,8 @@
+# insert and bubble with single empty space
+
+a 10 aa
+a 11 ab
+a 12 ac
+a 14 ad
+a 10 bc
+

hashtest/insert_discont.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=5>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:bc
+	12:11:ab
+	13:12:ac
+	14:14:ad
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/insert_full.tst

@@ -0,0 +1,40 @@
+# Insert on a full hash
+
+# First, fill the hash :-)
+
+a 0 aa
+a 1 ab
+a 2 ac
+a 3 ad
+a 4 ae
+a 5 af
+a 6 ag 
+a 7 ah
+a 8 ai
+a 9 af
+a 10 ba
+a 11 bb
+a 12 bc
+a 13 bd
+a 14 be 
+a 15 bf
+a 16 bg
+a 17 bh
+a 18 bi
+a 19 bj
+a 20 ca
+a 21 cb
+a 22 cd
+a 23 ce
+a 24 cf
+a 25 cg
+a 26 ch
+a 27 ci
+a 28 cj
+a 29 ck
+a 30 da
+a 31 db
+
+# it's full!
+a 20 zz
+a 31 za

hashtest/insert_full.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=32>
+	0:0:aa
+	1:1:ab
+	2:2:ac
+	3:3:ad
+	4:4:ae
+	5:5:af
+	6:6:ag
+	7:7:ah
+	8:8:ai
+	9:9:af
+	10:10:ba
+	11:11:bb
+	12:12:bc
+	13:13:bd
+	14:14:be
+	15:15:bf
+	16:16:bg
+	17:17:bh
+	18:18:bi
+	19:19:bj
+	20:20:ca
+	21:21:cb
+	22:22:cd
+	23:23:ce
+	24:24:cf
+	25:25:cg
+	26:26:ch
+	27:27:ci
+	28:28:cj
+	29:29:ck
+	30:30:da
+	31:31:db
+</hash>

hashtest/insert_full_floor.tst

@@ -0,0 +1,7 @@
+# wrap-around and insert at full floor
+a 2 ba
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+a 2 bb

hashtest/insert_full_floor.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=6>
+	0:30:ac
+	1:30:ad
+	2:2:ba
+	3:2:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/insert_wrap.tst

@@ -0,0 +1,7 @@
+# wrap-around and insert above floor
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+a 0 ba
+a 0 bb

hashtest/insert_wrap.tst.ref

@@ -0,0 +1,34 @@
+<hash elem=6>
+	0:30:ac
+	1:30:ad
+	2:0:ba
+	3:0:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/mkrand.pl

@@ -0,0 +1,41 @@
+#! /usr/bin/perl
+
+# Creates a script of random accesses and deletes
+
+use strict;
+
+
+my $i = 0;
+sub mkstr {
+    $i++;
+    return chr(ord('a') + ($i / 26) % 26) . chr(ord('a') + $i % 26);
+}
+
+my @elems;
+
+
+sub add_elem {
+    my $val = int(rand(32));
+    my $str = mkstr($val);
+    push @elems, "$val $str";
+    print "a $val $str\n";
+}
+
+sub del_elem {
+    my $remove = splice(@elems, rand @elems, 1);
+    print "d $remove\n";
+}
+
+while (1) {
+    if (@elems < 5) {
+        add_elem;
+    } elsif (@elems > 28) {
+        del_elem;
+    } else {
+        if (rand() < .5) {
+            add_elem;
+        } else {
+            del_elem;
+        }
+    }
+}

hashtest/run

@@ -0,0 +1,30 @@
+#! /usr/bin/perl -w
+
+# This runs all the tests.
+
+# Tests scripts are in *.tst files.
+# Corresponding output is put in *.out.
+# Reference output is put in *.ref.
+# Any discrepancy will be reported!
+
+use strict;
+
+my @res;
+foreach my $fn (`ls *.tst`) {
+    chomp $fn;
+    my $cmd = "./htest $fn $fn.out";
+    print "$cmd\n";
+    `$cmd`;
+    my $res = system("diff -u $fn.ref $fn.out");
+    push @res, [$fn, ($res == 0 ? "OK" : "*KO*")];
+}
+
+format =
+@<<<<<<<<<<<<<<<<<<<<<<<<<< @>>>
+$_->[0], $_->[1]
+.
+
+
+#format_name STDOUT test_result;
+map { write; } @res;
+

landlock.c

@@ -0,0 +1,183 @@
+/*
+ * Setup a sandbox using the Landlock LSM, if available.
+
+# Copyright (C) 2023  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+#
+*/
+
+#include "config.h"
+#include "log.h"
+
+#ifdef HAVE_LANDLOCK
+
+#define _GNU_SOURCE
+#include <linux/landlock.h>
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+
+/* Ubuntu 22.04 does not have this symbol */
+#ifndef LANDLOCK_ACCESS_FS_REFER
+#define LANDLOCK_ACCESS_FS_REFER			(1ULL << 13)
+#endif
+
+#ifndef landlock_create_ruleset
+static inline int
+landlock_create_ruleset(const struct landlock_ruleset_attr *const attr,
+			const size_t size, const __u32 flags)
+{
+	return syscall(__NR_landlock_create_ruleset, attr, size, flags);
+}
+#endif
+
+#ifndef landlock_add_rule
+static inline int landlock_add_rule(const int ruleset_fd,
+				    const enum landlock_rule_type rule_type,
+				    const void *const rule_attr,
+				    const __u32 flags)
+{
+	return syscall(__NR_landlock_add_rule, ruleset_fd, rule_type, rule_attr,
+		       flags);
+}
+#endif
+
+#ifndef landlock_restrict_self
+static inline int landlock_restrict_self(const int ruleset_fd,
+					 const __u32 flags)
+{
+	return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
+}
+#endif
+
+typedef enum {
+    LL_TREE,
+    LL_FILE
+} ll_obj_type;
+
+static int add_path_ro(int ruleset_fd, ll_obj_type otype, const char* path)
+{
+    int fd = open(path, O_PATH | O_CLOEXEC);
+    if (fd < 0) {
+        print_message(msg_config_error, "Landlock: Failed to open %s: %s\n", path, strerror(errno));
+        return -1;
+    }
+
+    struct landlock_path_beneath_attr path_beneath = {
+        .allowed_access = (otype == LL_TREE ? LANDLOCK_ACCESS_FS_READ_DIR : 0 ) |
+                          LANDLOCK_ACCESS_FS_READ_FILE,
+        .parent_fd = fd,
+    };
+
+    int res = landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, &path_beneath, 0);
+    if (res) {
+        print_message(msg_config_error, "Landlock: Failed to update the ruleset with \"%s\": %s\n",
+                path, strerror(errno));
+        close(path_beneath.parent_fd);
+        return -1;
+    }
+
+    return 0;
+}
+
+
+static int add_libs(int ruleset_fd)
+{
+    /* Access to libraries, to be able to fork */
+    add_path_ro(ruleset_fd, LL_TREE, "/lib");
+    add_path_ro(ruleset_fd, LL_TREE, "/usr/lib");
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/ld.so.cache");  /* To avoid searching all libs... */
+    return 0;
+}
+
+static int add_resolv(int ruleset_fd)
+{
+    /* Files to resolve names (required when dynamic resolution is used) */
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/hosts");
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/resolv.conf");
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/nsswitch.conf");
+    return 0;
+}
+
+static int add_libwrap(int ruleset_fd)
+{
+    /* Files for libwrap */
+#ifdef LIBWRAP
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/hosts.allow");
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/hosts.deny");
+#endif
+
+    return 0;
+}
+
+
+
+void setup_landlock(void)
+{
+    __u64 restrict_rules = 
+        LANDLOCK_ACCESS_FS_EXECUTE |
+        LANDLOCK_ACCESS_FS_READ_FILE |
+        LANDLOCK_ACCESS_FS_READ_DIR |
+        LANDLOCK_ACCESS_FS_WRITE_FILE |
+        LANDLOCK_ACCESS_FS_REMOVE_DIR |
+        LANDLOCK_ACCESS_FS_REMOVE_FILE |
+        LANDLOCK_ACCESS_FS_MAKE_CHAR |
+        LANDLOCK_ACCESS_FS_MAKE_DIR |
+        LANDLOCK_ACCESS_FS_MAKE_REG |
+        LANDLOCK_ACCESS_FS_MAKE_SOCK |
+        LANDLOCK_ACCESS_FS_MAKE_FIFO |
+        LANDLOCK_ACCESS_FS_MAKE_BLOCK |
+        LANDLOCK_ACCESS_FS_MAKE_SYM |
+        LANDLOCK_ACCESS_FS_REFER;
+
+    struct landlock_ruleset_attr ruleset_attr = {
+        .handled_access_fs = restrict_rules
+    };
+
+    /* ruleset_addr.handled_access_fs contains all rights that will be restricted
+     * unless explicitly added */
+    int ruleset_fd = landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+    if (ruleset_fd < 0) {
+        print_message(msg_config_error, "Landlock: Failed to create a ruleset");
+        return;
+    }
+
+
+    /* Add all the paths we need */
+    add_libs(ruleset_fd);
+    add_resolv(ruleset_fd);
+    add_libwrap(ruleset_fd);
+
+    if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
+        print_message(msg_config_error, "Landlock: Failed to restrict privileges");
+        return;
+    }
+    if (landlock_restrict_self(ruleset_fd, 0)) {
+        print_message(msg_config_error, "Landlock: Failed to enforce ruleset");
+        return;
+    }
+    close(ruleset_fd);
+
+    print_message(msg_config, "Landlock: all restricted\n");
+}
+
+#else /* HAVE_LANDLOCK */
+void setup_landlock(void)
+{
+    print_message(msg_config, "Landlock: not built in\n");
+    return;
+}
+#endif /* HAVE_LANDLOCK */

log.c

@@ -0,0 +1,211 @@
+/*
+# log: processing of all outgoing messages
+#
+# Copyright (C) 2007-2021  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+
+*/
+
+
+#define SYSLOG_NAMES
+#define _GNU_SOURCE
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include "sslh-conf.h"
+#include "common.h"
+#include "log.h"
+
+msg_info msg_config = {
+    LOG_INFO,
+    &cfg.verbose_config
+};
+
+msg_info msg_config_error = {
+    LOG_ERR,
+    &cfg.verbose_config_error
+};
+
+msg_info msg_fd = {
+    LOG_DEBUG,
+    &cfg.verbose_fd
+};
+
+/* Internal errors: inconsistent states, impossible values, things that should never happen, and are therefore the sign of memory corruption: hence the LOG_CRIT */
+msg_info msg_int_error = {
+    LOG_CRIT,
+    &cfg.verbose_system_error
+};
+
+/* System errors: when the system around us fails us: memory allocation, fork, ... */
+msg_info msg_system_error = {
+    LOG_ERR,
+    &cfg.verbose_system_error
+};
+
+msg_info msg_packets = {
+    LOG_INFO,
+    &cfg.verbose_packets
+};
+
+/* additional info when attempting outgoing connections */
+msg_info msg_connections_try = {
+    LOG_DEBUG,
+    &cfg.verbose_connections_try
+};
+
+/* Connection information and failures (e.g. forbidden by policy) */
+msg_info msg_connections = {
+    LOG_INFO,
+    &cfg.verbose_connections
+};
+
+/* Connection failures, e.g. target server not present */
+msg_info msg_connections_error = {
+    LOG_ERR,
+    &cfg.verbose_connections_error
+};
+
+
+/* comment the probing process */
+msg_info msg_probe_info = {
+    LOG_INFO,
+    &cfg.verbose_probe_info
+};
+
+/* probing errors, e.g. inconsistent data in connections */
+msg_info msg_probe_error = {
+    LOG_ERR,
+    &cfg.verbose_probe_error
+};
+
+
+
+/* Bitmasks in verbose-* values */
+#define MSG_STDOUT 1
+#define MSG_SYSLOG 2
+#define MSG_FILE   4
+
+static FILE* logfile_fp = NULL;
+
+/* Prints a message to stderr and/or syslog if appropriate */
+void print_message(msg_info info, const char* str, ...)
+{
+    va_list ap;
+
+    if ((*info.verbose & MSG_STDOUT) && ! cfg.inetd) {
+        va_start(ap, str);
+        vfprintf(stderr, str, ap);
+        va_end(ap);
+    }
+
+    if (*info.verbose & MSG_SYSLOG) {
+        va_start(ap, str);
+        vsyslog(info.log_level, str, ap);
+        va_end(ap);
+    }
+
+    if (*info.verbose & MSG_FILE && logfile_fp != NULL) {
+        va_start(ap, str);
+        vfprintf(logfile_fp, str, ap);
+        fflush(logfile_fp);
+        va_end(ap);
+    }
+}
+
+static int do_syslog = 1; /* Should we syslog? controled by syslog_facility = "none" */
+
+/* Open syslog connection with appropriate banner;
+ * banner is made up of basename(bin_name)+"[pid]" */
+void setup_syslog(const char* bin_name) {
+    char *name1, *name2;
+    int res, fn;
+
+    if (!strcmp(cfg.syslog_facility, "none")) {
+        do_syslog = 0;
+        return;
+    }
+
+    name1 = strdup(bin_name);
+    res = asprintf(&name2, "%s[%d]", basename(name1), getpid());
+    CHECK_RES_DIE(res, "asprintf");
+
+    for (fn = 0; facilitynames[fn].c_val != -1; fn++)
+        if (strcmp(facilitynames[fn].c_name, cfg.syslog_facility) == 0)
+            break;
+    if (facilitynames[fn].c_val == -1) {
+        fprintf(stderr, "Unknown facility %s\n", cfg.syslog_facility);
+        exit(1);
+    }
+
+    openlog(name2, LOG_CONS, facilitynames[fn].c_val);
+    free(name1);
+    /* Don't free name2, as openlog(3) uses it (at least in glibc) */
+}
+
+void setup_logfile()
+{
+    if (cfg.logfile == NULL)
+    {
+        return;
+    }
+
+    logfile_fp = fopen(cfg.logfile, "a");
+    if (logfile_fp == NULL)
+    {
+        fprintf(stderr, "Could not open logfile %s for writing: %s\n", cfg.logfile, strerror(errno));
+        exit(1);
+    }
+}
+
+void close_logfile()
+{
+    if (logfile_fp != NULL)
+    {
+        fclose(logfile_fp);
+        logfile_fp = NULL;
+    }
+}
+
+/* syslogs who connected to where 
+ * desc: string description of the connection. if NULL, log_connection will
+ * manage on its own
+ * cnx: connection descriptor
+ * */
+void log_connection(struct connection_desc* desc, const struct connection *cnx)
+{
+    struct connection_desc d;
+
+    if (cnx->proto->log_level < 1)
+        return;
+
+    if (!desc) {
+        desc = &d;
+        if (!get_connection_desc(desc, cnx)) {
+            print_message(msg_connections, "%s: lost incoming connection\n",
+                          cnx->proto->name);
+            return;
+        }
+    }
+
+    print_message(msg_connections, "%s:connection from %s to %s forwarded from %s to %s\n",
+                cnx->proto->name,
+                desc->peer,
+                desc->service,
+                desc->local,
+                desc->target);
+}

log.h

@@ -0,0 +1,36 @@
+#ifndef LOG_H
+#define LOG_H
+
+#include "common.h"
+
+void setup_syslog(const char* bin_name);
+
+void setup_logfile();
+
+void close_logfile();
+
+void log_connection(struct connection_desc* desc, const struct connection *cnx);
+
+typedef struct s_msg_info{
+    int log_level;
+    int *verbose;
+} msg_info;
+
+void print_message(msg_info info, const char* str, ...);
+extern msg_info msg_config;
+extern msg_info msg_config_error;
+
+extern msg_info msg_fd;
+extern msg_info msg_packets;
+
+extern msg_info msg_int_error;
+extern msg_info msg_system_error;
+
+extern msg_info msg_connections_try;
+extern msg_info msg_connections_error;
+extern msg_info msg_connections;
+
+extern msg_info msg_probe_info;
+extern msg_info msg_probe_error;
+
+#endif /* LOG_H */

probe.c

@@ -1,7 +1,7 @@
 /*
 # probe.c: Code for probing protocols
 #
-# Copyright (C) 2007-2019  Yves Rutschle
+# Copyright (C) 2007-2021  Yves Rutschle
 # 
 # This program is free software; you can redistribute it
 # and/or modify it under the terms of the GNU General Public
@@ -27,11 +27,13 @@
 #endif
 #include <ctype.h>
 #include "probe.h"
+#include "log.h"
 
 
 
 static int is_ssh_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
 static int is_openvpn_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
+static int is_wireguard_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
 static int is_tinc_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
 static int is_xmpp_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
 static int is_http_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
@@ -39,6 +41,8 @@ static int is_tls_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_
 static int is_adb_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
 static int is_socks5_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
 static int is_syslog_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
+static int is_teamspeak_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
+static int is_msrdp_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item*);
 static int is_true(const char *p, ssize_t len, struct sslhcfg_protocols_item* proto) { return 1; }
 
 /* Table of protocols that have a built-in probe
@@ -47,6 +51,7 @@ static struct protocol_probe_desc builtins[] = {
     /* description  probe  */
     { "ssh",        is_ssh_protocol},
     { "openvpn",    is_openvpn_protocol },
+    { "wireguard",  is_wireguard_protocol },
     { "tinc",       is_tinc_protocol },
     { "xmpp",       is_xmpp_protocol },
     { "http",       is_http_protocol },
@@ -54,6 +59,8 @@ static struct protocol_probe_desc builtins[] = {
     { "adb",        is_adb_protocol },
     { "socks5",     is_socks5_protocol },
     { "syslog",     is_syslog_protocol },
+    { "teamspeak",  is_teamspeak_protocol },
+    { "msrdp",      is_msrdp_protocol },
     { "anyprot",    is_true }
 };
 
@@ -81,33 +88,38 @@ struct sslhcfg_protocols_item* timeout_protocol(void)
 
 /* From http://grapsus.net/blog/post/Hexadecimal-dump-in-C */
 #define HEXDUMP_COLS 16
-void hexdump(const char *mem, unsigned int len)
+void hexdump(msg_info msg_info, const char *mem, unsigned int len)
 {
     unsigned int i, j;
+    char str[10 + HEXDUMP_COLS * 4 + 2];
+    int c = 0; /* index in str */
 
     for(i = 0; i < len + ((len % HEXDUMP_COLS) ? (HEXDUMP_COLS - len % HEXDUMP_COLS) : 0); i++)
     {
         /* print offset */
         if(i % HEXDUMP_COLS == 0)
-            fprintf(stderr, "0x%06x: ", i);
+            c += sprintf(&str[c], "0x%06x: ", i);
 
         /* print hex data */
         if(i < len)
-            fprintf(stderr, "%02x ", 0xFF & mem[i]);
+            c += sprintf(&str[c], "%02x ", 0xFF & mem[i]);
         else /* end of block, just aligning for ASCII dump */
-            fprintf(stderr, "   ");
+            c+= sprintf(&str[c], "   ");
 
         /* print ASCII dump */
         if(i % HEXDUMP_COLS == (HEXDUMP_COLS - 1)) {
             for(j = i - (HEXDUMP_COLS - 1); j <= i; j++) {
                 if(j >= len) /* end of block, not really printing */
-                    fputc(' ', stderr);
+                    str[c++] = ' ';
                 else if(isprint(mem[j])) /* printable char */
-                    fputc(0xFF & mem[j], stderr);
+                    str[c++] = 0xFF & mem[j];
                 else /* other char */
-                    fputc('.', stderr);
+                    str[c++] = '.';
             }
-            fputc('\n', stderr);
+            str[c++] = '\n';
+            str[c++] = 0;
+            print_message(msg_info, "%s", str);
+            c = 0;
         }
     }
 }
@@ -131,15 +143,66 @@ static int is_ssh_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_
  * http://www.fengnet.com/book/vpns%20illustrated%20tunnels%20%20vpnsand%20ipsec/ch08lev1sec5.html
  * and OpenVPN ssl.c, ssl.h and options.c
  */
+#define OVPN_OPCODE_MASK 0xF8
+#define OVPN_CONTROL_HARD_RESET_CLIENT_V1  (0x01 << 3)
+#define OVPN_CONTROL_HARD_RESET_CLIENT_V2  (0x07 << 3)
+#define OVPN_HMAC_128 16
+#define OVPN_HMAC_160 20
+#define OVPN_HARD_RESET_PACKET_ID_OFFSET(hmac_size) (9 + hmac_size)
 static int is_openvpn_protocol (const char*p,ssize_t len, struct sslhcfg_protocols_item* proto)
 {
     int packet_len;
 
-    if (len < 2)
-        return PROBE_AGAIN;
+    if (proto->is_udp == 0)
+    {
+        if (len < 2)
+            return PROBE_AGAIN;
 
-    packet_len = ntohs(*(uint16_t*)p);
-    return packet_len == len - 2;
+        packet_len = ntohs(*(uint16_t*)p);
+        return packet_len == len - 2;
+    } else {
+        if (len < 1)
+            return PROBE_NEXT;
+
+        if ((p[0] & OVPN_OPCODE_MASK) != OVPN_CONTROL_HARD_RESET_CLIENT_V1 &&
+            (p[0] & OVPN_OPCODE_MASK) != OVPN_CONTROL_HARD_RESET_CLIENT_V2)
+            return PROBE_NEXT;
+
+        /* The detection pattern above may not be reliable enough.
+         * Check the packet id: OpenVPN sents five initial packets
+         * whereas the packet id is increased with every transmitted datagram.
+         */
+
+        if (len <= OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_128) + sizeof(uint32_t))
+            return PROBE_NEXT;
+
+        if (ntohl(*(uint32_t*)(p + OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_128))) <= 5u)
+            return PROBE_MATCH;
+
+        if (len <= OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_160) + sizeof(uint32_t))
+            return PROBE_NEXT;
+
+        if (ntohl(*(uint32_t*)(p + OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_160))) <= 5u)
+            return PROBE_MATCH;
+
+        return PROBE_NEXT;
+    }
+}
+
+static int is_wireguard_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item* proto)
+{
+    if (proto->is_udp == 0)
+        return PROBE_NEXT;
+
+    // Handshake Init: 148 bytes
+    if (len != 148)
+        return PROBE_NEXT;
+
+    // Handshake Init: p[0] = 0x01, p[1..3] = 0x000000 (reserved)
+    if (ntohl(*(uint32_t*)p) != 0x01000000)
+        return PROBE_NEXT;
+
+    return PROBE_MATCH;
 }
 
 /* Is the buffer the beginning of a tinc connections?
@@ -260,7 +323,7 @@ static int is_adb_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_
     if (len < min_data_packet_size + sizeof(empty_message))
         return PROBE_AGAIN;
 
-    if (memcmp(&p[0], empty_message, sizeof(empty_message)))
+    if (memcmp(&p[0], empty_message, sizeof(empty_message)) != 0)
         return PROBE_NEXT;
 
     return probe_adb_cnxn_message(&p[sizeof(empty_message)]);
@@ -312,6 +375,27 @@ static int is_syslog_protocol(const char *p, ssize_t len, struct sslhcfg_protoco
     return 0;
 }
 
+static int is_teamspeak_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item* proto)
+{
+    if (len < 8)
+        return PROBE_NEXT;
+
+    return !strncmp(p, "TS3INIT1", len);
+}
+
+static int is_msrdp_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item* proto)
+{
+    char version;
+    char packet_len;
+    if (len < 7)
+        return PROBE_NEXT;
+    version=*p;
+    if (version!=0x03)
+        return 0;
+    packet_len = ntohs(*(uint16_t*)(p+2));
+    return packet_len == len;
+}
+
 static int regex_probe(const char *p, ssize_t len, struct sslhcfg_protocols_item* proto)
 {
 #ifdef ENABLE_REGEX
@@ -328,51 +412,58 @@ static int regex_probe(const char *p, ssize_t len, struct sslhcfg_protocols_item
     return 0;
 #else
     /* Should never happen as we check when loading config file */
-    fprintf(stderr, "FATAL: regex probe called but not built in\n");
+    print_message(msg_int_error, "FATAL: regex probe called but not built in\n");
     exit(5);
 #endif
 }
 
 /* Run all the probes on a buffer
+ * buf, len: buffer to test on
+ * proto_in, proto_len: array of protocols to try
+ * proto_out: protocol that matched
+ *
  * Returns
  *      PROBE_AGAIN if not enough data, and set *proto to NULL
  *      PROBE_MATCH if protocol is identified, in which case *proto is set to
  *      point to the appropriate protocol
  * */
-int probe_buffer(char* buf, int len, struct sslhcfg_protocols_item** proto)
+int probe_buffer(char* buf, int len,
+                 struct sslhcfg_protocols_item** proto_in,
+                 int proto_len,
+                 struct sslhcfg_protocols_item** proto_out
+                 )
 {
     struct sslhcfg_protocols_item* p;
     int i, res, again = 0;
 
-    if (cfg.verbose > 1) {
-        fprintf(stderr, "hexdump of incoming packet:\n");
-        hexdump(buf, len);
-    }
+    print_message(msg_packets, "hexdump of incoming packet:\n");
+    hexdump(msg_packets, buf, len);
 
-    *proto = NULL;
-    for (i = 0; i < cfg.protocols_len; i++) {
+    *proto_out = NULL;
+    for (i = 0; i < proto_len; i++) {
         char* probe_str[3] = {"PROBE_NEXT", "PROBE_MATCH", "PROBE_AGAIN"};
-        p = &cfg.protocols[i];
+        p = proto_in[i];
 
         if (! p->probe) continue;
 
-        if (cfg.verbose) fprintf(stderr, "probing for %s\n", p->name);
+        print_message(msg_probe_info, "probing for %s\n", p->name);
 
         /* Don't probe last protocol if it is anyprot (and store last protocol) */
-        if ((i == cfg.protocols_len - 1) && (!strcmp(p->name, "anyprot")))
+        if ((i == proto_len - 1) && (!strcmp(p->name, "anyprot")))
             break;
 
         if (p->minlength_is_present && (len < p->minlength )) {
-            fprintf(stderr, "input too short, %d bytes but need %d\n", len , p->minlength);
+            print_message(msg_probe_info, "input too short, %d bytes but need %d\n", 
+                          len , p->minlength);
             again++;
             continue;
         }
 
         res = p->probe(buf, len, p);
-        if (cfg.verbose) fprintf(stderr, "probed for %s: %s\n", p->name, probe_str[res]);
+        print_message(msg_probe_info, "probed for %s: %s\n", p->name, probe_str[res]);
 
         if (res == PROBE_MATCH) {
-            *proto = p;
+            *proto_out = p;
             return PROBE_MATCH;
         }
         if (res == PROBE_AGAIN)
@@ -382,37 +473,14 @@ int probe_buffer(char* buf, int len, struct sslhcfg_protocols_item** proto)
         return PROBE_AGAIN;
 
     /* Everything failed: match the last one */
-    *proto = &cfg.protocols[cfg.protocols_len-1];
-    return PROBE_MATCH;
-}
 
-/*
- * Read the beginning of data coming from the client connection and check if
- * it's a known protocol.
- * Return PROBE_AGAIN if not enough data, or PROBE_MATCH if it succeeded in
- * which case cnx->proto is set to the appropriate protocol.
- */
-int probe_client_protocol(struct connection *cnx)
-{
-    char buffer[BUFSIZ];
-    ssize_t n;
-
-    n = read(cnx->q[0].fd, buffer, sizeof(buffer));
-    /* It's possible that read() returns an error, e.g. if the client
-     * disconnected between the previous call to select() and now. If that
-     * happens, we just connect to the default protocol so the caller of this
-     * function does not have to deal with a specific  failure condition (the
-     * connection will just fail later normally). */
-
-    if (n > 0) {
-        defer_write(&cnx->q[1], buffer, n);
-        return probe_buffer(cnx->q[1].begin_deferred_data,
-                            cnx->q[1].deferred_data_size,
-                            &cnx->proto);
+    if (proto_len == 0) {
+        /* This should be caught by configuration sanity checks, but just in
+         * case, die gracefully rather than segfaulting */
+        print_message(msg_int_error, "Received traffic on transport that has no target\n");
+        exit(0);
     }
-
-    /* read() returned an error, so just connect to the last protocol to die */
-    cnx->proto = &cfg.protocols[cfg.protocols_len-1];
+    *proto_out = proto_in[proto_len-1];
     return PROBE_MATCH;
 }
 

probe.h

@@ -5,6 +5,7 @@
 
 #include "common.h"
 #include "tls.h"
+#include "log.h"
 
 typedef enum {
     PROBE_NEXT,  /* Enough data, probe failed -- it's some other protocol */
@@ -47,8 +48,12 @@ void set_protocol_list(struct sslhcfg_protocols_item*);
  */
 int probe_client_protocol(struct connection *cnx);
 
-/* Probe, but on a buffer */
-int probe_buffer(char* buf, int len, struct sslhcfg_protocols_item** proto);
+/* Probe on a buffer */
+int probe_buffer(char* buf, int len,
+                 struct sslhcfg_protocols_item** proto_in,
+                 int proto_len,
+                 struct sslhcfg_protocols_item** proto_out
+                 );
 
 /* set the protocol to connect to in case of timeout */
 void set_ontimeout(const char* name);
@@ -59,6 +64,6 @@ void set_ontimeout(const char* name);
  */
 struct sslhcfg_protocols_item* timeout_protocol(void);
 
-void hexdump(const char*, unsigned int);
+void hexdump(msg_info, const char*, unsigned int);
 
 #endif

processes.c

@@ -0,0 +1,115 @@
+/* 
+  Processes that are common to sslh-ev and sslh-select
+ 
+# Copyright (C) 2021  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+
+*/
+
+#include "udp-listener.h"
+#include "tcp-listener.h"
+#include "processes.h"
+#include "probe.h"
+#include "log.h"
+
+
+int tidy_connection(struct connection *cnx, struct loop_info* fd_info)
+{
+    int i;
+
+    for (i = 0; i < 2; i++) {
+        if (cnx->q[i].fd != -1) {
+            print_message(msg_fd, "closing fd %d\n", cnx->q[i].fd);
+
+            watchers_del_read(fd_info->watchers, cnx->q[i].fd);
+            watchers_del_write(fd_info->watchers, cnx->q[i].fd);
+            close(cnx->q[i].fd);
+            if (cnx->q[i].deferred_data)
+                free(cnx->q[i].deferred_data);
+        }
+    }
+
+    if (cnx->type == SOCK_DGRAM)
+        udp_tidy(cnx, fd_info);
+
+    if (gap_remove_ptr(fd_info->probing_list, cnx, fd_info->num_probing) != -1)
+        fd_info->num_probing--;
+
+    collection_remove_cnx(fd_info->collection, cnx);
+    return 0;
+}
+
+
+
+/* Process a connection that is active in read */
+
+void cnx_read_process(struct loop_info* fd_info, int fd)
+{
+    cnx_collection* collection = fd_info->collection;
+    struct connection* cnx = collection_get_cnx_from_fd(collection, fd);
+    switch (cnx->type)  {
+    case SOCK_STREAM:
+        tcp_read_process(fd_info, fd);
+        break;
+
+    case SOCK_DGRAM:
+        udp_s2c_forward(cnx);
+        break;
+
+    default:
+        print_message(msg_int_error, "cnx_read_process: Illegal connection type %d\n", cnx->type);
+        dump_connection(cnx);
+        exit(1);
+    }
+}
+
+
+/* Process a connection that accepts a socket
+ * (For UDP, this means all traffic coming from remote clients)
+ * Returns new connection object, or NULL
+ * */
+struct connection* cnx_accept_process(struct loop_info* fd_info, struct listen_endpoint* listen_socket)
+{
+    int fd = listen_socket->socketfd;
+    int type = listen_socket->type;
+    struct connection* cnx;
+
+    switch (type) {
+    case SOCK_STREAM:
+        cnx = accept_new_connection(fd, fd_info);
+        if (!cnx) return NULL;
+
+        break;
+
+    case SOCK_DGRAM:
+        cnx = udp_c2s_forward(fd, fd_info);
+        if (!cnx) return NULL;
+        break;
+
+    default:
+        print_message(msg_int_error, "Inconsistent cnx type: %d\n", type);
+        exit(1);
+    }
+
+    int new_fd = cnx->q[0].fd;
+    watchers_add_read(fd_info->watchers, new_fd);
+    return cnx;
+}
+
+
+
+

processes.h

@@ -0,0 +1,41 @@
+#ifndef PROCESSES_H
+#define PROCESSES_H
+
+#include "common.h"
+#include "collection.h"
+#include "gap.h"
+
+typedef struct connection* hash_item;
+#include "hash.h"
+
+/* Provided by event loop, sslh-ev or sslh-select, for implementation-dependant
+ * data */
+typedef struct watchers watchers; 
+
+/* Global state for a loop */
+struct loop_info {
+    int num_probing;     /* Number of connections currently probing 
+                          * We use this to know if we need to time out of
+                          * select() */
+    gap_array* probing_list;  /* Pointers to cnx that are in probing mode */
+
+    hash* hash_sources; /* UDP remote sources previously encountered */
+
+    watchers* watchers;
+
+    cnx_collection* collection; /* Collection of connections linked to this loop */
+};
+
+void cnx_read_process(struct loop_info* fd_info, int fd);
+struct connection* cnx_accept_process(struct loop_info* fd_info, struct listen_endpoint* listen_socket);
+
+int tidy_connection(struct connection *cnx, struct loop_info* fd_info);
+
+
+/* These must be declared in the loop handler, sslh-ev or sslh-select */
+void watchers_add_read(watchers* w, int fd);
+void watchers_del_read(watchers* w, int fd);
+void watchers_add_write(watchers* w, int fd);
+void watchers_del_write(watchers* w, int fd);
+
+#endif

scripts/etc.sysconfig.sslh

@@ -18,7 +18,7 @@
 #CONFIG=/etc/sslh.cfg
 
 #
-# Extra option to pass on comand line
+# Extra option to pass on command line
 # Those can supersede configuration file settings
 # 
 #OPTIONS=

scripts/fail2ban/sslh-ssh.conf

@@ -8,7 +8,7 @@
 # but many connection attempts from the same
 # origin is reason enough to block.
 #
-# Verion: 2014-03-28
+# Version: 2014-03-28
 
 [INCLUDES]
 
@@ -16,7 +16,7 @@
 
 [Definition]
 
-failregex = ^.+ sslh\[.+\]: connection from <HOST>:.+ to .+ forwarded
+failregex = ^.+ sslh\[.+\]: ssh:connection from <HOST>:.+ to .+ forwarded
 from .+ to .+:ssh\s*$
 
 ignoreregex =

scripts/systemd.sslh-select@.service

@@ -0,0 +1,27 @@
+[Unit]
+Description=SSL/SSH multiplexer (select mode) for %I
+After=network.target
+
+[Service]
+EnvironmentFile=/etc/default/sslh
+ExecStart=/usr/sbin/sslh-select -F/etc/sslh/%I.cfg -f $DAEMON_OPTS
+KillMode=process
+#Hardening
+PrivateTmp=true
+CapabilityBoundingSet=CAP_NET_BIND_SERVICE
+AmbientCapabilities=CAP_NET_BIND_SERVICE
+SecureBits=noroot-locked
+ProtectSystem=strict
+ProtectHome=true
+ProtectKernelModules=true
+ProtectKernelTunables=true
+ProtectControlGroups=true
+MountFlags=private
+NoNewPrivileges=true
+PrivateDevices=true
+RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX
+MemoryDenyWriteExecute=true
+DynamicUser=true
+
+[Install]
+WantedBy=multi-user.target

scripts/systemd.sslh@.service

@@ -1,10 +1,10 @@
 [Unit]
-Description=SSL/SSH multiplexer
+Description=SSL/SSH multiplexer (fork mode) for %I
 After=network.target
 
 [Service]
-EnvironmentFile=/etc/conf.d/sslh
-ExecStart=/usr/sbin/sslh --foreground $DAEMON_OPTS
+EnvironmentFile=/etc/default/sslh
+ExecStart=/usr/sbin/sslh -F/etc/sslh/%I.cfg -f $DAEMON_OPTS
 KillMode=process
 #Hardening
 PrivateTmp=true

sslh-conf.c

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Tue Aug 24 13:53:04 2021. 
+ * on Tue Jan  2 21:25:47 2024. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2021  Yves Rutschle
@@ -443,33 +443,48 @@ struct compound_cl_arg {
 
 
 struct arg_file* sslhcfg_conffile;
- struct arg_int* sslhcfg_verbose;
+ struct arg_int* sslhcfg_verbose_config;
+ struct arg_int* sslhcfg_verbose_config_error;
+ struct arg_int* sslhcfg_verbose_connections;
+ struct arg_int* sslhcfg_verbose_connections_try;
+ struct arg_int* sslhcfg_verbose_connections_error;
+ struct arg_int* sslhcfg_verbose_fd;
+ struct arg_int* sslhcfg_verbose_packets;
+ struct arg_int* sslhcfg_verbose_probe_info;
+ struct arg_int* sslhcfg_verbose_probe_error;
+ struct arg_int* sslhcfg_verbose_system_error;
+ struct arg_int* sslhcfg_verbose_int_error;
  struct arg_lit* sslhcfg_version;
  struct arg_lit* sslhcfg_foreground;
  struct arg_lit* sslhcfg_inetd;
  struct arg_lit* sslhcfg_numeric;
  struct arg_lit* sslhcfg_transparent;
  struct arg_int* sslhcfg_timeout;
+ struct arg_int* sslhcfg_udp_max_connections;
  struct arg_str* sslhcfg_user;
  struct arg_str* sslhcfg_pidfile;
  struct arg_str* sslhcfg_chroot;
  struct arg_str* sslhcfg_syslog_facility;
+ struct arg_str* sslhcfg_logfile;
  struct arg_str* sslhcfg_on_timeout;
  struct arg_str* sslhcfg_prefix;
  	struct arg_str* sslhcfg_listen;
  	struct arg_str* sslhcfg_ssh;
  	struct arg_str* sslhcfg_tls;
+ 	struct arg_str* sslhcfg_ssl;
  	struct arg_str* sslhcfg_openvpn;
  	struct arg_str* sslhcfg_tinc;
+ 	struct arg_str* sslhcfg_wireguard;
  	struct arg_str* sslhcfg_xmpp;
  	struct arg_str* sslhcfg_http;
  	struct arg_str* sslhcfg_adb;
  	struct arg_str* sslhcfg_socks5;
  	struct arg_str* sslhcfg_syslog;
+ 	struct arg_str* sslhcfg_msrdp;
  	struct arg_str* sslhcfg_anyprot;
  struct arg_end* sslhcfg_end;
 
-                                                                                                                                               
+                                                                                                                                                        
 static struct config_desc table_sslhcfg_protocols[] = {
 
 
@@ -617,6 +632,22 @@ static struct config_desc table_sslhcfg_protocols[] = {
             /* default_val*/    .default_val.def_bool = 0 
         },
 
+        { 
+            /* name */          "resolve_on_forward", 
+            /* type */          CFG_BOOL, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        NULL,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_protocols_item, resolve_on_forward),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_bool = 0 
+        },
+
         { 
             /* name */          "log_level", 
             /* type */          CFG_INT, 
@@ -783,17 +814,17 @@ static struct config_desc table_sslhcfg_listen[] = {
         },
 	{ 0 }
 };
-                                                                                                                      
+                                                                                                                                                                                                                                  
 static struct config_desc table_sslhcfg[] = {
 
 
         { 
-            /* name */          "verbose", 
+            /* name */          "verbose_config", 
             /* type */          CFG_INT, 
             /* sub_group*/      NULL,
-            /* arg_cl */        & sslhcfg_verbose,
+            /* arg_cl */        & sslhcfg_verbose_config,
             /* base_addr */     NULL,
-            /* offset */        offsetof(struct sslhcfg_item, verbose),
+            /* offset */        offsetof(struct sslhcfg_item, verbose_config),
             /* offset_len */    0,
             /* offset_present */ 0,
             /* size */          sizeof(int), 
@@ -803,6 +834,166 @@ static struct config_desc table_sslhcfg[] = {
             /* default_val*/    .default_val.def_int = 0 
         },
 
+        { 
+            /* name */          "verbose_config_error", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_config_error,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_config_error),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 3 
+        },
+
+        { 
+            /* name */          "verbose_connections", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_connections,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_connections),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 3 
+        },
+
+        { 
+            /* name */          "verbose_connections_try", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_connections_try,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_connections_try),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 0 
+        },
+
+        { 
+            /* name */          "verbose_connections_error", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_connections_error,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_connections_error),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 3 
+        },
+
+        { 
+            /* name */          "verbose_fd", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_fd,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_fd),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 0 
+        },
+
+        { 
+            /* name */          "verbose_packets", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_packets,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_packets),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 0 
+        },
+
+        { 
+            /* name */          "verbose_probe_info", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_probe_info,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_probe_info),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 0 
+        },
+
+        { 
+            /* name */          "verbose_probe_error", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_probe_error,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_probe_error),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 3 
+        },
+
+        { 
+            /* name */          "verbose_system_error", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_system_error,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_system_error),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 3 
+        },
+
+        { 
+            /* name */          "verbose_int_error", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_verbose_int_error,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, verbose_int_error),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 3 
+        },
+
         { 
             /* name */          "version", 
             /* type */          CFG_BOOL, 
@@ -899,6 +1090,22 @@ static struct config_desc table_sslhcfg[] = {
             /* default_val*/    .default_val.def_int = 5 
         },
 
+        { 
+            /* name */          "udp_max_connections", 
+            /* type */          CFG_INT, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_udp_max_connections,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, udp_max_connections),
+            /* offset_len */    0,
+            /* offset_present */ 0,
+            /* size */          sizeof(int), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      0, 
+            /* default_val*/    .default_val.def_int = 1024 
+        },
+
         { 
             /* name */          "user", 
             /* type */          CFG_STRING, 
@@ -963,6 +1170,22 @@ static struct config_desc table_sslhcfg[] = {
             /* default_val*/    .default_val.def_string = "auth" 
         },
 
+        { 
+            /* name */          "logfile", 
+            /* type */          CFG_STRING, 
+            /* sub_group*/      NULL,
+            /* arg_cl */        & sslhcfg_logfile,
+            /* base_addr */     NULL,
+            /* offset */        offsetof(struct sslhcfg_item, logfile),
+            /* offset_len */    0,
+            /* offset_present */ offsetof(struct sslhcfg_item, logfile_is_present),
+            /* size */          sizeof(char*), 
+            /* array_type */    -1,
+            /* mandatory */     0, 
+            /* optional */      1, 
+            /* default_val*/    .default_val.def_string = NULL 
+        },
+
         { 
             /* name */          "on_timeout", 
             /* type */          CFG_STRING, 
@@ -1032,7 +1255,15 @@ static struct compound_cl_target sslhcfg_anyprot_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "anyprot" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
+	{ 0 }
+};
+
+static struct compound_cl_target sslhcfg_msrdp_targets [] = {
+	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "msrdp" },
+	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ 0 }
 };
 
@@ -1040,7 +1271,7 @@ static struct compound_cl_target sslhcfg_syslog_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "syslog" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ 0 }
 };
 
@@ -1048,7 +1279,7 @@ static struct compound_cl_target sslhcfg_socks5_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "socks5" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ 0 }
 };
 
@@ -1056,7 +1287,7 @@ static struct compound_cl_target sslhcfg_adb_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "adb" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ 0 }
 };
 
@@ -1064,7 +1295,7 @@ static struct compound_cl_target sslhcfg_http_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "http" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ 0 }
 };
 
@@ -1072,7 +1303,16 @@ static struct compound_cl_target sslhcfg_xmpp_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "xmpp" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
+	{ 0 }
+};
+
+static struct compound_cl_target sslhcfg_wireguard_targets [] = {
+	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "wireguard" },
+	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[7], 0, .value.def_bool = 1 },
 	{ 0 }
 };
 
@@ -1080,7 +1320,7 @@ static struct compound_cl_target sslhcfg_tinc_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "tinc" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ & table_sslhcfg_protocols[7], 0, .value.def_bool = 1 },
 	{ 0 }
 };
@@ -1089,7 +1329,16 @@ static struct compound_cl_target sslhcfg_openvpn_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "openvpn" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[7], 0, .value.def_bool = 1 },
+	{ 0 }
+};
+
+static struct compound_cl_target sslhcfg_ssl_targets [] = {
+	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "tls" },
+	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ & table_sslhcfg_protocols[7], 0, .value.def_bool = 1 },
 	{ 0 }
 };
@@ -1098,7 +1347,7 @@ static struct compound_cl_target sslhcfg_tls_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "tls" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ & table_sslhcfg_protocols[7], 0, .value.def_bool = 1 },
 	{ 0 }
 };
@@ -1108,7 +1357,7 @@ static struct compound_cl_target sslhcfg_ssh_targets [] = {
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
 	{ & table_sslhcfg_protocols[6], 0, .value.def_bool = 1 },
-	{ & table_sslhcfg_protocols[9], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
 	{ & table_sslhcfg_protocols[7], 0, .value.def_bool = 1 },
 	{ 0 }
 };
@@ -1123,7 +1372,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: listen */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_listen,
-            .base_entry =      & table_sslhcfg [13],
+            .base_entry =      & table_sslhcfg [25],
             .targets =         sslhcfg_listen_targets,
 
 
@@ -1135,7 +1384,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: ssh */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_ssh,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_ssh_targets,
 
 
@@ -1147,7 +1396,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: tls */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_tls,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_tls_targets,
 
 
@@ -1156,10 +1405,22 @@ static struct compound_cl_arg compound_cl_args[] = {
             .override_const = "tls",
         },
 
+        {   /* arg: ssl */
+            .regex =           "(.+):(\\w+)",
+            .arg_cl =          & sslhcfg_ssl,
+            .base_entry =      & table_sslhcfg [26],
+            .targets =         sslhcfg_ssl_targets,
+
+
+            .override_desc =   & table_sslhcfg_protocols [0],
+            .override_matchindex = 0,
+            .override_const = "tls",
+        },
+
         {   /* arg: openvpn */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_openvpn,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_openvpn_targets,
 
 
@@ -1171,7 +1432,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: tinc */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_tinc,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_tinc_targets,
 
 
@@ -1180,10 +1441,22 @@ static struct compound_cl_arg compound_cl_args[] = {
             .override_const = "tinc",
         },
 
+        {   /* arg: wireguard */
+            .regex =           "(.+):(\\w+)",
+            .arg_cl =          & sslhcfg_wireguard,
+            .base_entry =      & table_sslhcfg [26],
+            .targets =         sslhcfg_wireguard_targets,
+
+
+            .override_desc =   & table_sslhcfg_protocols [0],
+            .override_matchindex = 0,
+            .override_const = "wireguard",
+        },
+
         {   /* arg: xmpp */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_xmpp,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_xmpp_targets,
 
 
@@ -1195,7 +1468,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: http */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_http,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_http_targets,
 
 
@@ -1207,7 +1480,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: adb */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_adb,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_adb_targets,
 
 
@@ -1219,7 +1492,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: socks5 */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_socks5,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_socks5_targets,
 
 
@@ -1231,7 +1504,7 @@ static struct compound_cl_arg compound_cl_args[] = {
         {   /* arg: syslog */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_syslog,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_syslog_targets,
 
 
@@ -1240,10 +1513,22 @@ static struct compound_cl_arg compound_cl_args[] = {
             .override_const = "syslog",
         },
 
+        {   /* arg: msrdp */
+            .regex =           "(.+):(\\w+)",
+            .arg_cl =          & sslhcfg_msrdp,
+            .base_entry =      & table_sslhcfg [26],
+            .targets =         sslhcfg_msrdp_targets,
+
+
+            .override_desc =   & table_sslhcfg_protocols [0],
+            .override_matchindex = 0,
+            .override_const = "msrdp",
+        },
+
         {   /* arg: anyprot */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_anyprot,
-            .base_entry =      & table_sslhcfg [14],
+            .base_entry =      & table_sslhcfg [26],
             .targets =         sslhcfg_anyprot_targets,
 
 
@@ -1908,29 +2193,44 @@ int sslhcfg_cl_parse(int argc, char* argv[], struct sslhcfg_item* cfg)
             #ifdef LIBCONFIG
         sslhcfg_conffile = arg_filen("F", "config", "<file>", 0, 1, "Specify configuration file"),
     #endif
-         sslhcfg_verbose = arg_intn("v", "verbose", "<n>", 0, 1, ""),
+         sslhcfg_verbose_config = arg_intn(NULL, "verbose-config", "<n>", 0, 1, "Print configuration at startup"),
+         sslhcfg_verbose_config_error = arg_intn(NULL, "verbose-config-error", "<n>", 0, 1, "Print configuration errors"),
+         sslhcfg_verbose_connections = arg_intn(NULL, "verbose-connections", "<n>", 0, 1, "Trace established incoming address to forward address"),
+         sslhcfg_verbose_connections_try = arg_intn(NULL, "verbose-connections-try", "<n>", 0, 1, "Connection errors"),
+         sslhcfg_verbose_connections_error = arg_intn(NULL, "verbose-connections-error", "<n>", 0, 1, "Connection attempts towards targets"),
+         sslhcfg_verbose_fd = arg_intn(NULL, "verbose-fd", "<n>", 0, 1, "File descriptor activity, open/close/whatnot"),
+         sslhcfg_verbose_packets = arg_intn(NULL, "verbose-packets", "<n>", 0, 1, "Hexdump packets on which probing is done"),
+         sslhcfg_verbose_probe_info = arg_intn(NULL, "verbose-probe-info", "<n>", 0, 1, "Trace the probe process"),
+         sslhcfg_verbose_probe_error = arg_intn(NULL, "verbose-probe-error", "<n>", 0, 1, "Failures and problems during probing"),
+         sslhcfg_verbose_system_error = arg_intn(NULL, "verbose-system-error", "<n>", 0, 1, "System call failures"),
+         sslhcfg_verbose_int_error = arg_intn(NULL, "verbose-int-error", "<n>", 0, 1, "Internal errors that should never happen"),
          sslhcfg_version = arg_litn("V", "version", 0, 1, "Print version information and exit"),
          sslhcfg_foreground = arg_litn("f", "foreground", 0, 1, "Run in foreground instead of as a daemon"),
          sslhcfg_inetd = arg_litn("i", "inetd", 0, 1, "Run in inetd mode: use stdin/stdout instead of network listen"),
          sslhcfg_numeric = arg_litn("n", "numeric", 0, 1, "Print IP addresses and ports as numbers"),
          sslhcfg_transparent = arg_litn(NULL, "transparent", 0, 1, "Set up as a transparent proxy"),
          sslhcfg_timeout = arg_intn("t", "timeout", "<n>", 0, 1, "Set up timeout before connecting to default target"),
+         sslhcfg_udp_max_connections = arg_intn(NULL, "udp-max-connections", "<n>", 0, 1, "Number of concurrent UDP connections"),
          sslhcfg_user = arg_strn("u", "user", "<str>", 0, 1, "Username to change to after set-up"),
          sslhcfg_pidfile = arg_strn("P", "pidfile", "<file>", 0, 1, "Path to file to store PID of current instance"),
          sslhcfg_chroot = arg_strn("C", "chroot", "<path>", 0, 1, "Root to change to after set-up"),
          sslhcfg_syslog_facility = arg_strn(NULL, "syslog-facility", "<str>", 0, 1, "Facility to syslog to"),
+         sslhcfg_logfile = arg_strn(NULL, "logfile", "<str>", 0, 1, "Log messages to a file"),
          sslhcfg_on_timeout = arg_strn(NULL, "on-timeout", "<str>", 0, 1, "Target to connect to when timing out"),
          sslhcfg_prefix = arg_strn(NULL, "prefix", "<str>", 0, 1, "Reserved for testing"),
  	sslhcfg_listen = arg_strn("p", "listen", "<host:port>", 0, 10, "Listen on host:port"),
  	sslhcfg_ssh = arg_strn(NULL, "ssh", "<host:port>", 0, 10, "Set up ssh target"),
  	sslhcfg_tls = arg_strn(NULL, "tls", "<host:port>", 0, 10, "Set up TLS/SSL target"),
+ 	sslhcfg_ssl = arg_strn(NULL, "ssl", "<host:port>", 0, 10, "Set up TLS/SSL target"),
  	sslhcfg_openvpn = arg_strn(NULL, "openvpn", "<host:port>", 0, 10, "Set up OpenVPN target"),
  	sslhcfg_tinc = arg_strn(NULL, "tinc", "<host:port>", 0, 10, "Set up tinc target"),
+ 	sslhcfg_wireguard = arg_strn(NULL, "wireguard", "<host:port>", 0, 10, "Set up WireGuard target"),
  	sslhcfg_xmpp = arg_strn(NULL, "xmpp", "<host:port>", 0, 10, "Set up XMPP target"),
  	sslhcfg_http = arg_strn(NULL, "http", "<host:port>", 0, 10, "Set up HTTP (plain) target"),
  	sslhcfg_adb = arg_strn(NULL, "adb", "<host:port>", 0, 10, "Set up ADB (Android Debug) target"),
  	sslhcfg_socks5 = arg_strn(NULL, "socks5", "<host:port>", 0, 10, "Set up socks5 target"),
  	sslhcfg_syslog = arg_strn(NULL, "syslog", "<host:port>", 0, 10, "Set up syslog target"),
+ 	sslhcfg_msrdp = arg_strn(NULL, "msrdp", "<host:port>", 0, 10, "Set up msrdp target"),
  	sslhcfg_anyprot = arg_strn(NULL, "anyprot", "<host:port>", 0, 10, "Set up default target"),
  	sslhcfg_end = arg_end(10)
 
@@ -1939,10 +2239,13 @@ int sslhcfg_cl_parse(int argc, char* argv[], struct sslhcfg_item* cfg)
     /* Parse command line */
     nerrors = arg_parse(argc, argv, argtable);
     if (nerrors) {
-        arg_print_errors(stdout, sslhcfg_end, "sslhcfg"); 
+        // print bad args
+        arg_print_errors(stdout, sslhcfg_end, "sslhcfg");
+        // print usage
         arg_print_syntax(stdout, argtable, "\n");
+        // print options
         arg_print_glossary(stdout, argtable, "  %-25s\t%s\n");
-        return -1;
+        fprintf(stderr, "Invalid args are ignored, please fix them\n");
     }
 
 
@@ -2020,6 +2323,9 @@ static void sslhcfg_protocols_fprint(
         fprintf(out, "transparent: %d", sslhcfg_protocols->transparent);
         fprintf(out, "\n");
         indent(out, depth);
+        fprintf(out, "resolve_on_forward: %d", sslhcfg_protocols->resolve_on_forward);
+        fprintf(out, "\n");
+        indent(out, depth);
         fprintf(out, "log_level: %d", sslhcfg_protocols->log_level);
         fprintf(out, "\n");
         indent(out, depth);
@@ -2077,7 +2383,37 @@ void sslhcfg_fprint(
 {
     int i;
         indent(out, depth);
-        fprintf(out, "verbose: %d", sslhcfg->verbose);
+        fprintf(out, "verbose_config: %d", sslhcfg->verbose_config);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_config_error: %d", sslhcfg->verbose_config_error);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_connections: %d", sslhcfg->verbose_connections);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_connections_try: %d", sslhcfg->verbose_connections_try);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_connections_error: %d", sslhcfg->verbose_connections_error);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_fd: %d", sslhcfg->verbose_fd);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_packets: %d", sslhcfg->verbose_packets);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_probe_info: %d", sslhcfg->verbose_probe_info);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_probe_error: %d", sslhcfg->verbose_probe_error);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_system_error: %d", sslhcfg->verbose_system_error);
+        fprintf(out, "\n");
+        indent(out, depth);
+        fprintf(out, "verbose_int_error: %d", sslhcfg->verbose_int_error);
         fprintf(out, "\n");
         indent(out, depth);
         fprintf(out, "version: %d", sslhcfg->version);
@@ -2098,6 +2434,9 @@ void sslhcfg_fprint(
         fprintf(out, "timeout: %d", sslhcfg->timeout);
         fprintf(out, "\n");
         indent(out, depth);
+        fprintf(out, "udp_max_connections: %d", sslhcfg->udp_max_connections);
+        fprintf(out, "\n");
+        indent(out, depth);
         fprintf(out, "user: %s", sslhcfg->user);
         if (! sslhcfg->user_is_present)
             fprintf(out, " <unset>");
@@ -2116,6 +2455,11 @@ void sslhcfg_fprint(
         fprintf(out, "syslog_facility: %s", sslhcfg->syslog_facility);
         fprintf(out, "\n");
         indent(out, depth);
+        fprintf(out, "logfile: %s", sslhcfg->logfile);
+        if (! sslhcfg->logfile_is_present)
+            fprintf(out, " <unset>");
+        fprintf(out, "\n");
+        indent(out, depth);
         fprintf(out, "on_timeout: %s", sslhcfg->on_timeout);
         fprintf(out, "\n");
         indent(out, depth);

sslh-conf.h

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Tue Aug 24 13:53:04 2021. 
+ * on Tue Jan  2 21:25:47 2024. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2021  Yves Rutschle
@@ -58,6 +58,7 @@ struct sslhcfg_protocols_item {
 	int	fork;
 	int	tfo_ok;
 	int	transparent;
+	int	resolve_on_forward;
 	int	log_level;
 	int	keepalive;
 	size_t	sni_hostnames_len;
@@ -71,16 +72,28 @@ struct sslhcfg_protocols_item {
 	T_PROBE*	probe;
 	struct addrinfo*	saddr;
 	void*	data;
+	dl_list	timeouts;
 };
 
 struct sslhcfg_item {
-	int	verbose;
+	int	verbose_config;
+	int	verbose_config_error;
+	int	verbose_connections;
+	int	verbose_connections_try;
+	int	verbose_connections_error;
+	int	verbose_fd;
+	int	verbose_packets;
+	int	verbose_probe_info;
+	int	verbose_probe_error;
+	int	verbose_system_error;
+	int	verbose_int_error;
 	int	version;
 	int	foreground;
 	int	inetd;
 	int	numeric;
 	int	transparent;
 	int	timeout;
+	int	udp_max_connections;
 	int	user_is_present;
 	char*	user;
 	int	pidfile_is_present;
@@ -88,6 +101,8 @@ struct sslhcfg_item {
 	int	chroot_is_present;
 	char*	chroot;
 	char*	syslog_facility;
+	int	logfile_is_present;
+	char*	logfile;
 	char*	on_timeout;
 	char*	prefix;
 	size_t	listen_len;

sslh-ev.c

@@ -0,0 +1,153 @@
+/*
+   sslh-ev: mono-processus server based on libev
+
+# Copyright (C) 2021  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+
+*/
+
+#include <stdlib.h>
+#include <ev.h>
+#include "gap.h"
+#include "log.h"
+#include "udp-listener.h"
+#include "tcp-listener.h"
+
+
+const char* server_type = "sslh-ev";
+
+static struct ev_loop* loop;
+
+/* Libev watchers */
+struct watchers {
+    /* one set of ev_io for read, one for write, indexed by file descriptor */
+    gap_array *ev_ior, *ev_iow;
+
+    struct listen_endpoint* listen_sockets;
+    gap_array* fd2ls;  /* Array indexed by file descriptor, pointing to listen_sockets */
+};
+
+static void cnx_read_cb(EV_P_ ev_io *w, int revents);
+static void cnx_write_cb(EV_P_ ev_io *w, int wevents);
+static void cnx_accept_cb(EV_P_ ev_io *w, int revents);
+
+
+static void watchers_init(watchers** w, struct listen_endpoint* listen_sockets, 
+                          int num_addr_listen)
+{
+    *w = malloc(sizeof(**w));
+    (*w)->ev_ior = gap_init(num_addr_listen);
+    (*w)->ev_iow = gap_init(num_addr_listen);
+    (*w)->listen_sockets = listen_sockets;
+    (*w)->fd2ls = gap_init(0);
+
+    /* Create watchers for listen sockets */
+    for (int i = 0; i < num_addr_listen; i++) {
+        ev_io* io = malloc(sizeof(*io));
+
+        ev_io_init(io, &cnx_accept_cb, listen_sockets[i].socketfd, EV_READ);
+        ev_io_start(EV_A_  io);
+        gap_set((*w)->ev_ior, i, io);
+        gap_set((*w)->fd2ls, listen_sockets[i].socketfd, &listen_sockets[i]);
+        set_nonblock(listen_sockets[i].socketfd);
+    }
+}
+
+void watchers_add_read(watchers* w, int fd)
+{
+    ev_io* io = gap_get(w->ev_ior, fd);
+    if (!io) {
+        io = malloc(sizeof(*io));
+        ev_io_init(io, &cnx_read_cb, fd, EV_READ);
+        ev_io_set(io, fd, EV_READ);
+
+        gap_set(w->ev_ior, fd, io);
+    }
+    ev_io_start(loop, io);
+}
+
+void watchers_del_read(watchers* w, int fd)
+{
+    ev_io* io = gap_get(w->ev_ior, fd);
+    if (io) ev_io_stop(EV_A_ io);
+}
+
+void watchers_add_write(watchers* w, int fd)
+{
+    ev_io* io = gap_get(w->ev_iow, fd);
+    if (!io) {
+        io = malloc(sizeof(*io));
+        ev_io_init(io, &cnx_write_cb, fd, EV_WRITE);
+        ev_io_set(io, fd, EV_WRITE);
+
+        gap_set(w->ev_iow, fd, io);
+    }
+    ev_io_start(loop, io);
+}
+
+void watchers_del_write(watchers* w, int fd)
+{
+    ev_io* io = gap_get(w->ev_iow, fd);
+    if (io) ev_io_stop(EV_A_ io);
+}
+
+/* /watchers */
+
+#include "processes.h"
+
+/* Libev callbacks */
+static void cnx_read_cb(EV_P_ ev_io *w, int revents)
+{
+    struct loop_info* info = ev_userdata(EV_A);
+    cnx_read_process(info, w->fd);
+}
+
+static void cnx_write_cb(EV_P_ ev_io *w, int wevents)
+{
+    struct loop_info* info = ev_userdata(EV_A);
+    cnx_write_process(info, w->fd);
+}
+
+
+static void cnx_accept_cb(EV_P_ ev_io *w, int revents)
+{
+    struct loop_info* info = ev_userdata(EV_A);
+    cnx_accept_process(info, gap_get(info->watchers->fd2ls, w->fd));
+}
+
+void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
+{
+    struct loop_info ev_info = {0};
+    loop = EV_DEFAULT;
+
+    ev_info.collection = collection_init(0);
+    ev_info.probing_list = gap_init(0);
+    udp_init(&ev_info);
+    tcp_init();
+
+    watchers_init(&ev_info.watchers, listen_sockets, num_addr_listen);
+    ev_set_userdata(EV_A_ &ev_info);
+
+    ev_run(EV_A_ 0);
+}
+
+void start_shoveler(int listen_socket) {
+    print_message(msg_config_error, "inetd mode is not supported in libev mode\n");
+    exit(1);
+}
+
+

sslh-fork.c

@@ -23,7 +23,8 @@
 #include "common.h"
 #include "probe.h"
 #include "sslh-conf.h"
-#include "udp-listener.h"
+#include "tcp-probe.h"
+#include "log.h"
 
 #ifdef LIBBSD
 #include <bsd/unistd.h>
@@ -58,8 +59,7 @@ int shovel(struct connection *cnx)
           if (FD_ISSET(cnx->q[i].fd, &fds)) {
               res = fd2fd(&cnx->q[1-i], &cnx->q[i]);
               if (res == FD_CNXCLOSED) {
-                  if (cfg.verbose) 
-                      fprintf(stderr, "%s %s", i ? "client" : "server", "socket closed\n");
+                  print_message(msg_fd, "%s %s", i ? "client" : "server", "socket closed\n");
                   return res;
               }
           }
@@ -99,8 +99,7 @@ void start_shoveler(int in_socket)
        } else {
            /* Timed out: it's necessarily SSH */
            cnx.proto = timeout_protocol();
-           if (cfg.verbose) 
-               log_message(LOG_INFO, "timed out, connect to %s\n", cnx.proto->name);
+           print_message(msg_fd, "timed out, connect to %s\n", cnx.proto->name);
            break;
        }
    }
@@ -129,8 +128,7 @@ void start_shoveler(int in_socket)
    close(in_socket);
    close(out_socket);
    
-   if (cfg.verbose)
-      fprintf(stderr, "connection closed down\n");
+   print_message(msg_fd, "connection closed down\n");
 
    exit(0);
 }
@@ -166,6 +164,13 @@ void set_listen_procname(struct listen_endpoint *listen_socket)
 }
 
 
+/* At least MacOS does not know these two options, so define them to something
+ * equivalent for our use case */
+#ifndef ENONET
+#define ENONET EWOULDBLOCK
+#endif
+/* /MacOS kludge */
+
 /* TCP listener: connections, fork a child for each new connection 
  * IN: 
  *      endpoint: array of listening endpoint objects
@@ -179,10 +184,30 @@ void tcp_listener(struct listen_endpoint* endpoint, int num_endpoints, int activ
 
     while (1) {
         in_socket = accept(endpoint[active_endpoint].socketfd, 0, 0);
-        if (cfg.verbose) fprintf(stderr, "accepted fd %d\n", in_socket);
+        CHECK_RES_RETURN(in_socket, "accept", /*void*/ );
+        if (in_socket == -1) {
+            print_message(msg_system_error, "%s:%d:%s:%d:%s\n", 
+                          __FILE__, __LINE__, "accept", errno, strerror(errno));
+            switch(in_socket) {
+            case ENETDOWN:  /* accept(2) cites all these errnos as "you should retry" */
+            case EPROTO:
+            case ENOPROTOOPT:
+            case EHOSTDOWN:
+            case ENONET:
+            case EHOSTUNREACH:
+            case EOPNOTSUPP:
+            case ENETUNREACH:
+            case ECONNABORTED:
+                continue;
+
+            default:  /* Otherwise, it's something wrong in our parameters, we fail */
+                return;
+            }
+        }
+        print_message(msg_fd, "accepted fd %d\n", in_socket);
 
         switch(fork()) {
-        case -1: log_message(LOG_ERR, "fork failed: err %d: %s\n", errno, strerror(errno));
+        case -1: print_message(msg_system_error, "fork failed: err %d: %s\n", errno, strerror(errno));
                  break;
 
         case 0: /* In child process */
@@ -209,20 +234,24 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
     listener_pid = malloc(listener_pid_number * sizeof(listener_pid[0]));
     CHECK_ALLOC(listener_pid, "malloc");
 
+    tcp_init();
+
     /* Start one process for each listening address */
     for (i = 0; i < num_addr_listen; i++) {
         listener_pid[i] = fork();
         switch(listener_pid[i]) {
         /* Log if fork() fails for some reason */
-        case -1: log_message(LOG_ERR, "fork failed: err %d: %s\n", errno, strerror(errno));
+        case -1: print_message(msg_system_error, "fork failed: err %d: %s\n", errno, strerror(errno));
                  break;
         /* We're in the child, we have work to do  */
         case 0:
             set_listen_procname(&listen_sockets[i]);
             if (listen_sockets[i].type == SOCK_DGRAM)
-                log_message(LOG_ERR, "UDP not (yet?) supported in sslh-fork\n");
+                print_message(msg_config_error, "UDP not (yet?) supported in sslh-fork\n");
             else
                 tcp_listener(listen_sockets, num_addr_listen, i);
+
+            exit(0);
 	    break;
 
 	/* We're in the parent, we don't need to do anything */

sslh-main.c

@@ -36,6 +36,8 @@
 
 #include "common.h"
 #include "probe.h"
+#include "log.h"
+#include "tcp-probe.h"
 
 /* Constants for options that have no one-character shorthand */
 #define OPT_ONTIMEOUT   257
@@ -50,7 +52,7 @@ static void printcaps(void) {
 
     desc = cap_to_text(caps, &len);
 
-    fprintf(stderr, "capabilities: %s\n", desc);
+    print_message(msg_config, "capabilities: %s\n", desc);
 
     cap_free(caps);
     cap_free(desc);
@@ -59,34 +61,46 @@ static void printcaps(void) {
 
 static void printsettings(void)
 {
-    char buf[NI_MAXHOST];
+    char buf[NI_MAXHOST + 256]; /* 256 > " family %d %d" for reasonable ints */
     int i;
     struct sslhcfg_protocols_item *p;
     
     for (i = 0; i < cfg.protocols_len; i++ ) {
         p = &cfg.protocols[i];
-        fprintf(stderr,
-                "%s addr: %s. libwrap service: %s log_level: %d family %d %d [%s] [%s] [%s]\n",
-                p->name, 
-                sprintaddr(buf, sizeof(buf), p->saddr), 
-                p->service,
-                p->log_level,
-                p->saddr->ai_family,
-                p->saddr->ai_addr->sa_family,
-                p->keepalive ? "keepalive" : "",
-                p->fork ? "fork" : "",
-                p->transparent ? "transparent" : ""
-                );
+        strcpy(buf, "resolve on forward");
+        if (!p->resolve_on_forward) {
+            sprintaddr(buf, sizeof(buf), p->saddr);
+            size_t len = strlen(buf);
+            sprintf(buf+len, " family %d %d", 
+                    p->saddr->ai_family,
+                    p->saddr->ai_addr->sa_family);
+        }
+        print_message(msg_config, 
+                      "%s addr: %s. libwrap service: %s log_level: %d [%s] [%s] [%s]\n",
+                      p->name, 
+                      buf,
+                      p->service,
+                      p->log_level,
+                      p->keepalive ? "keepalive" : "",
+                      p->fork ? "fork" : "",
+                      p->transparent ? "transparent" : ""
+                     );
     }
-    fprintf(stderr, "timeout: %d\non-timeout: %s\n", cfg.timeout,
-            timeout_protocol()->name);
+    print_message(msg_config, 
+                  "timeout: %d\n"
+                  "on-timeout: %s\n"
+                  "UDP hash size: %d\n", 
+                  cfg.timeout,
+                  timeout_protocol()->name,
+                  cfg.udp_max_connections);
 }
 
 
 static void setup_regex_probe(struct sslhcfg_protocols_item *p)
 #ifdef ENABLE_REGEX
 {
-    int num_patterns, i, error;
+    size_t num_patterns, i;
+    int error;
     pcre2_code** pattern_list;
     PCRE2_SIZE error_offset;
     PCRE2_UCHAR8 err_str[120];
@@ -103,7 +117,7 @@ static void setup_regex_probe(struct sslhcfg_protocols_item *p)
                                         &error, &error_offset, NULL);
         if (!pattern_list[i]) {
             pcre2_get_error_message(error, err_str, sizeof(err_str));
-            fprintf(stderr, "compiling pattern /%s/:%d:%s at offset %ld\n",
+            print_message(msg_config_error, "compiling pattern /%s/:%d:%s at offset %ld\n",
                     p->regex_patterns[i], error, err_str, error_offset);
             exit(1);
         }
@@ -123,14 +137,19 @@ static void config_protocols()
     int i;
     for (i = 0; i < cfg.protocols_len; i++) {
         struct sslhcfg_protocols_item* p = &(cfg.protocols[i]);
-        if (resolve_split_name(&(p->saddr), p->host, p->port)) {
-            fprintf(stderr, "cannot resolve %s:%s\n", p->host, p->port);
+
+        if (
+            !p->resolve_on_forward &&
+            resolve_split_name(&(p->saddr), p->host, p->port)
+        ) {
+            print_message(msg_config_error, "cannot resolve %s:%s\n",
+                          p->host, p->port);
             exit(4);
         }
 
         p->probe = get_probe(p->name);
         if (!p->probe) {
-            fprintf(stderr, "%s: probe unknown\n", p->name);
+            print_message(msg_config_error, "%s: probe unknown\n", p->name);
             exit(1);
         }
 
@@ -149,23 +168,55 @@ static void config_protocols()
                                   (const char**) cfg.protocols[i].alpn_protocols,
                                   cfg.protocols[i].alpn_protocols_len);
         }
+
+        p->timeouts.head = NULL;
+        p->timeouts.tail = NULL;
     }
 }
 
 
-void config_sanity_check(struct sslhcfg_item* cfg) {
-    if (!cfg->protocols_len) {
-        fprintf(stderr, "At least one target protocol must be specified.\n");
-        exit(2);
-    }
+void config_sanity_check(struct sslhcfg_item* cfg)
+{
+    size_t i;
 
 /* If compiling with systemd socket support no need to require listen address */
 #ifndef SYSTEMD
     if (!cfg->listen_len && !cfg->inetd) {
-        fprintf(stderr, "No listening address specified; use at least one -p option\n");
+        print_message(msg_config_error, "No listening address specified; use at least one -p option\n");
         exit(1);
     }
 #endif
+
+    for (i = 0; i < cfg->protocols_len; ++i) {
+        if (strcmp(cfg->protocols[i].name, "tls") != 0) {
+            if (cfg->protocols[i].sni_hostnames_len) {
+                print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
+                              "Config option sni_hostnames is only applicable for tls\n",
+                              cfg->protocols[i].name, cfg->protocols[i].host, cfg->protocols[i].port);
+                exit(1);
+            }
+            if (cfg->protocols[i].alpn_protocols_len) {
+                print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
+                              "Config option alpn_protocols is only applicable for tls\n",
+                              cfg->protocols[i].name, cfg->protocols[i].host, cfg->protocols[i].port);
+                exit(1);
+            }
+        }
+
+        if (cfg->protocols[i].is_udp) {
+            if (cfg->protocols[i].tfo_ok) {
+                print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
+                              "Config option tfo_ok is not applicable for udp connections\n",
+                              cfg->protocols[i].name, cfg->protocols[i].host, cfg->protocols[i].port);
+                exit(1);
+            }
+        } else {
+            if (!strcmp(cfg->protocols[i].name, "wireguard")) {
+                print_message(msg_config_error, "Wireguard works only with UDP\n");
+                exit(1);
+            }
+        }
+    }
 }
 
 
@@ -184,8 +235,6 @@ int main(int argc, char *argv[], char* envp[])
    memset(&cfg, 0, sizeof(cfg));
    res = sslhcfg_cl_parse(argc, argv, &cfg);
    if (res) exit(6);
-   if (cfg.verbose > 3)
-       sslhcfg_fprint(stderr, &cfg, 0);
 
    if (cfg.version) {
        printf("%s %s\n", server_type, VERSION);
@@ -197,19 +246,19 @@ int main(int argc, char *argv[], char* envp[])
 
    if (cfg.inetd)
    {
-       cfg.verbose = 0;
+       close(fileno(stderr)); /* Make sure no error will go to client */
+       tcp_init();
        start_shoveler(0);
        exit(0);
    }
 
-   if (cfg.verbose)
-       printsettings();
+   printsettings();
 
    num_addr_listen = start_listen_sockets(&listen_sockets);
 
 #ifdef SYSTEMD
    if (num_addr_listen < 1) {
-     fprintf(stderr, "No listening sockets found, restart sockets or specify addresses in config\n");
+     print_message(msg_config_error, "No listening sockets found, restart sockets or specify addresses in config\n");
      exit(1);
     }
 #endif
@@ -232,13 +281,22 @@ int main(int argc, char *argv[], char* envp[])
    /* Open syslog connection before we drop privs/chroot */
    setup_syslog(argv[0]);
 
+   /* Open log file for writing */
+   setup_logfile();
+
    if (cfg.user || cfg.chroot)
        drop_privileges(cfg.user, cfg.chroot);
+   setup_landlock();
 
-   if (cfg.verbose)
-       printcaps();
+   printcaps();
+
+   print_message(msg_config, "%s %s started\n", server_type, VERSION);
 
    main_loop(listen_sockets, num_addr_listen);
 
+   close_logfile();
+
+   free(listen_sockets);
+
    return 0;
 }

sslh-select.c

@@ -25,483 +25,88 @@
  * https://daniel.haxx.se/docs/poll-vs-select.html suggests that over a few
  * hundred file descriptors, both become very slow, so there is little
  * incentive to move to poll() to support more than FD_SETSIZE (which is 1024
- * on many Linux. To support large numbers of descriptors, either use the fork
- * version, or we'll have to write a new version based on libev. */
+ * on many Linux. To support large numbers of descriptors efficiently, either use sslh-fork
+ * or sslh-ev. */
 
 #define __LINUX__
 
-#include <limits.h>
-
 #include "common.h"
 #include "probe.h"
+#include "tcp-listener.h"
 #include "udp-listener.h"
 #include "collection.h"
+#include "processes.h"
 #include "gap.h"
-
-static int debug = 0;
+#include "log.h"
 
 const char* server_type = "sslh-select";
 
-/* Global state for a select() loop */
-struct select_info {
-    int max_fd;   /* Highest fd number to pass to select() */
-
-    int num_probing;     /* Number of connections currently probing 
-                          * We use this to know if we need to time out of
-                          * select() */
-    gap_array* probing_list;  /* Pointers to cnx that are in probing mode */
-
+/* watcher type for a select() loop */
+struct watchers {
     fd_set fds_r, fds_w;  /* reference fd sets (used to init working copies) */
-    cnx_collection* collection; /* Collection of connections linked to this loop */
-
-    time_t next_timeout; /* time at which next UDP connection times out */
+    int max_fd;   /* Highest fd number to pass to select() */
 };
 
 
-
-static int tidy_connection(struct connection *cnx, struct select_info* fd_info)
+static void watchers_init(watchers** w, struct listen_endpoint* listen_sockets,
+                          int num_addr_listen)
 {
-    int i;
-    fd_set* fds = &fd_info->fds_r;
-    fd_set* fds2 = &fd_info->fds_w;
+    *w = malloc(sizeof(**w));
+    CHECK_ALLOC(*w, "malloc");
 
-    for (i = 0; i < 2; i++) {
-        if (cnx->q[i].fd != -1) {
-            if (cfg.verbose)
-                fprintf(stderr, "closing fd %d\n", cnx->q[i].fd);
+    memset(*w, 0, sizeof(**w));
+    FD_ZERO(&(*w)->fds_r);
+    FD_ZERO(&(*w)->fds_w);
 
-            FD_CLR(cnx->q[i].fd, fds);
-            FD_CLR(cnx->q[i].fd, fds2);
-            close(cnx->q[i].fd);
-            if (cnx->q[i].deferred_data)
-                free(cnx->q[i].deferred_data);
-        }
+    for (int i = 0; i < num_addr_listen; i++) {
+        watchers_add_read(*w, listen_sockets[i].socketfd);
+        set_nonblock(listen_sockets[i].socketfd);
     }
-    collection_remove_cnx(fd_info->collection, cnx);
-    return 0;
 }
 
+void watchers_add_read(watchers* w, int fd)
+{
+    FD_SET(fd, &w->fds_r); 
+    if (fd + 1 > w->max_fd)
+        w->max_fd = fd + 1;
+}
+
+void watchers_del_read(watchers* w, int fd)
+{
+    FD_CLR(fd, &w->fds_r);
+}
+
+void watchers_add_write(watchers* w, int fd)
+{
+    FD_SET(fd, &w->fds_w); 
+    if (fd > w->max_fd)
+        w->max_fd = fd + 1;
+}
+
+void watchers_del_write(watchers* w, int fd)
+{
+    FD_CLR(fd, &w->fds_w);
+}
+
+/* /end watchers */
+
+
+
+
 /* if fd becomes higher than FD_SETSIZE, things won't work so well with FD_SET
  * and FD_CLR. Need to drop connections if we go above that limit */
-static int fd_is_in_range(int fd) {
+static int fd_out_of_range(int fd) {
     if (fd >= FD_SETSIZE) {
-        log_message(LOG_ERR, "too many open file descriptor to monitor them all -- dropping connection\n");
-        return 0;
+        print_message(msg_system_error, "too many open file descriptor to monitor them all -- dropping connection\n");
+        return 1;
     }
-    return 1;
-}
-
-/* Accepts a connection from the main socket and assigns it to an empty slot.
- * If no slots are available, allocate another few. If that fails, drop the
- * connexion */
-static struct connection* accept_new_connection(int listen_socket, struct cnx_collection *collection)
-{
-    int in_socket, res;
-
-
-    if (cfg.verbose) fprintf(stderr, "accepting from %d\n", listen_socket);
-
-    in_socket = accept(listen_socket, 0, 0);
-    CHECK_RES_RETURN(in_socket, "accept", NULL);
-
-    if (!fd_is_in_range(in_socket)) {
-        close(in_socket);
-        return NULL;
-    }
-
-    res = set_nonblock(in_socket);
-    if (res == -1) {
-        close(in_socket);
-        return NULL;
-    }
-
-    struct connection* cnx = collection_alloc_cnx_from_fd(collection, in_socket);
-    if (!cnx) {
-        close(in_socket);
-        return NULL;
-    }
-
-    return cnx;
+    return 0;
 }
 
 
-/* Connect queue 1 of connection to SSL; returns new file descriptor */
-static int connect_queue(struct connection* cnx,
-                         struct select_info* fd_info)
-{
-    struct queue *q = &cnx->q[1];
-
-    q->fd = connect_addr(cnx, cnx->q[0].fd, NON_BLOCKING);
-    if ((q->fd != -1) && fd_is_in_range(q->fd)) {
-        log_connection(NULL, cnx);
-        flush_deferred(q);
-        if (q->deferred_data) {
-            FD_SET(q->fd, &fd_info->fds_w);
-            FD_CLR(cnx->q[0].fd, &fd_info->fds_r);
-        }
-        FD_SET(q->fd, &fd_info->fds_r);
-        collection_add_fd(fd_info->collection, cnx, q->fd);
-        return q->fd;
-    } else {
-        tidy_connection(cnx, fd_info);
-        return -1;
-    }
-}
-
-/* shovels data from active fd to the other
-   returns after one socket closed or operation would block
- */
-static void shovel(struct connection *cnx, int active_fd, struct select_info* fd_info)
-{
-    struct queue *read_q, *write_q;
-
-    read_q = &cnx->q[active_fd];
-    write_q = &cnx->q[1-active_fd];
-
-    if (cfg.verbose)
-        fprintf(stderr, "activity on fd%d\n", read_q->fd);
-
-    switch(fd2fd(write_q, read_q)) {
-    case -1:
-    case FD_CNXCLOSED:
-        tidy_connection(cnx, fd_info);
-        break;
-
-    case FD_STALLED:
-        FD_SET(write_q->fd, &fd_info->fds_w);
-        FD_CLR(read_q->fd, &fd_info->fds_r);
-        break;
-
-    default: /* Nothing */
-        break;
-    }
-}
-
-/* shovels data from one fd to the other and vice-versa
-   returns after one socket closed
- */
-static void shovel_single(struct connection *cnx)
-{
-   fd_set fds_r, fds_w;
-   int res, i;
-   int max_fd = MAX(cnx->q[0].fd, cnx->q[1].fd) + 1;
-
-   FD_ZERO(&fds_r);
-   FD_ZERO(&fds_w);
-   while (1) {
-      for (i = 0; i < 2; i++) {
-         if (cnx->q[i].deferred_data_size) {
-            FD_SET(cnx->q[i].fd, &fds_w);
-            FD_CLR(cnx->q[1-i].fd, &fds_r);
-         } else {
-            FD_CLR(cnx->q[i].fd, &fds_w);
-            FD_SET(cnx->q[1-i].fd, &fds_r);
-         }
-      }
-
-      res = select(
-                   max_fd,
-                   &fds_r,
-                   &fds_w,
-                   NULL,
-                   NULL
-                  );
-      CHECK_RES_DIE(res, "select");
-
-      for (i = 0; i < 2; i++) {
-          if (FD_ISSET(cnx->q[i].fd, &fds_w)) {
-              res = flush_deferred(&cnx->q[i]);
-              if ((res == -1) && ((errno == EPIPE) || (errno == ECONNRESET))) {
-                  if (cfg.verbose)
-                      fprintf(stderr, "%s socket closed\n", i ? "server" : "client");
-                  return;
-              }
-          }
-          if (FD_ISSET(cnx->q[i].fd, &fds_r)) {
-              res = fd2fd(&cnx->q[1-i], &cnx->q[i]);
-              if (!res) {
-                  if (cfg.verbose)
-                      fprintf(stderr, "socket closed\n");
-                  return;
-              }
-          }
-      }
-   }
-}
-
-/* Child process that makes internal connection and proxies
- */
-static void connect_proxy(struct connection *cnx)
-{
-    int in_socket;
-    int out_socket;
-
-    /* Minimize the file descriptor value to help select() */
-    in_socket = dup(cnx->q[0].fd);
-    if (in_socket == -1) {
-        in_socket = cnx->q[0].fd;
-    } else {
-        close(cnx->q[0].fd);
-        cnx->q[0].fd = in_socket;
-    }
-
-    /* Connect the target socket */
-    out_socket = connect_addr(cnx, in_socket, BLOCKING);
-    CHECK_RES_DIE(out_socket, "connect");
-
-    cnx->q[1].fd = out_socket;
-
-    log_connection(NULL, cnx);
-
-    shovel_single(cnx);
-
-    close(in_socket);
-    close(out_socket);
-
-    if (cfg.verbose)
-        fprintf(stderr, "connection closed down\n");
-
-    exit(0);
-}
-
-/* Removes cnx from probing list */
-static void remove_probing_cnx(struct select_info* fd_info, struct connection* cnx)
-{
-    gap_remove_ptr(fd_info->probing_list, cnx, fd_info->num_probing);
-    fd_info->num_probing--;
-}
-
-static void add_probing_cnx(struct select_info* fd_info, struct connection* cnx)
-{
-    gap_set(fd_info->probing_list, fd_info->num_probing, cnx);
-    fd_info->num_probing++;
-}
 
 
-/* Process read activity on a socket in probe state 
- * IN/OUT cnx: connection data, updated if connected
- * IN/OUT info: updated if connected
- * */
 
-static void probing_read_process(struct connection* cnx,
-                                 struct select_info* fd_info)
-{
-    int res;
-
-    /* If timed out it's SSH, otherwise the client sent
-     * data so probe the protocol */
-    if ((cnx->probe_timeout < time(NULL))) {
-        cnx->proto = timeout_protocol();
-        if (cfg.verbose) 
-            log_message(LOG_INFO, 
-                        "timed out, connect to %s\n", 
-                        cnx->proto->name);
-    } else {
-        res = probe_client_protocol(cnx);
-        if (res == PROBE_AGAIN)
-            return;
-    }
-
-    remove_probing_cnx(fd_info, cnx);
-    cnx->state = ST_SHOVELING;
-
-    /* libwrap check if required for this protocol */
-    if (cnx->proto->service &&
-        check_access_rights(cnx->q[0].fd, cnx->proto->service)) {
-        tidy_connection(cnx, fd_info);
-        res = -1;
-    } else if (cnx->proto->fork) {
-        switch (fork()) {
-        case 0:  /* child */
-            /* TODO: close all file descriptors except 2 */
-            /* free(cnx); */
-            connect_proxy(cnx);
-            exit(0);
-        case -1: log_message(LOG_ERR, "fork failed: err %d: %s\n", errno, strerror(errno));
-                 break;
-        default: /* parent */
-                 break;
-        }
-        tidy_connection(cnx, fd_info);
-        res = -1;
-    } else {
-        res = connect_queue(cnx, fd_info);
-    }
-
-    if (res >= fd_info->max_fd)
-        fd_info->max_fd = res + 1;;
-}
-
-
-/* Returns the queue index that contains the specified file descriptor */
-int active_queue(struct connection* cnx, int fd)
-{
-    if (cnx->q[0].fd == fd) return 0;
-    if (cnx->q[1].fd == fd) return 1;
-
-    log_message(LOG_ERR, "file descriptor %d not found in connection object\n", fd);
-    return -1;
-}
-
-/* Process a connection that is active in read */
-static void tcp_read_process(struct select_info* fd_info,
-                             int fd)
-{
-    if (debug) fprintf(stderr, "cnx_read_process fd %d\n", fd);
-
-    cnx_collection* collection = fd_info->collection;
-    struct connection* cnx = collection_get_cnx_from_fd(collection, fd);
-    /* Determine active queue (0 or 1): if fd is that of q[1], active_q = 1,
-     * otherwise it's 0 */
-    int active_q = active_queue(cnx, fd);
-
-    switch (cnx->state) {
-
-    case ST_PROBING:
-        if (active_q == 1) {
-            fprintf(stderr, "Activity on fd2 while probing, impossible\n");
-            dump_connection(cnx);
-            exit(1);
-        }
-
-        probing_read_process(cnx, fd_info);
-
-        break;
-
-    case ST_SHOVELING:
-        shovel(cnx, active_q, fd_info);
-        break;
-
-    default: /* illegal */
-        log_message(LOG_ERR, "Illegal connection state %d\n", cnx->state);
-        dump_connection(cnx);
-        exit(1);
-    }
-}
-
-static void cnx_read_process(struct select_info* fd_info, int fd)
-{
-    cnx_collection* collection = fd_info->collection;
-    struct connection* cnx = collection_get_cnx_from_fd(collection, fd);
-    switch (cnx->type)  {
-    case SOCK_STREAM:
-        tcp_read_process(fd_info, fd);
-        break;
-
-    case SOCK_DGRAM:
-        udp_s2c_forward(cnx);
-        break;
-
-    default:
-        log_message(LOG_ERR, "cnx_read_process: Illegal connection type %d\n", cnx->type);
-        dump_connection(cnx);
-        exit(1);
-    }
-
-}
-
-/* Process a connection that is active in write */
-static void cnx_write_process(struct select_info* fd_info, int fd)
-{
-    if (debug) fprintf(stderr, "cnx_write_process fd %d\n", fd);
-
-    struct connection* cnx = collection_get_cnx_from_fd(fd_info->collection, fd);
-    int res;
-    int queue = active_queue(cnx, fd);
-
-    res = flush_deferred(&cnx->q[queue]);
-    if ((res == -1) && ((errno == EPIPE) || (errno == ECONNRESET))) {
-        if (cnx->state == ST_PROBING) remove_probing_cnx(fd_info, cnx);
-        tidy_connection(cnx, fd_info);
-    } else {
-        /* If no deferred data is left, stop monitoring the fd 
-         * for write, and restart monitoring the other one for reads*/
-        if (!cnx->q[queue].deferred_data_size) {
-            FD_CLR(cnx->q[queue].fd, &fd_info->fds_w);
-            FD_SET(cnx->q[1-queue].fd, &fd_info->fds_r);
-        }
-    }
-}
-
-/* Process a connection that accepts a socket
- * (For UDP, this means all traffic coming from remote clients)
- * */
-void cnx_accept_process(struct select_info* fd_info, struct listen_endpoint* listen_socket)
-{
-    int fd = listen_socket->socketfd;
-    int type = listen_socket->type;
-    struct connection* cnx;
-    int new_fd;
-
-    if (debug) fprintf(stderr, "cnx_accept_process fd %d\n", fd);
-
-    switch (type) {
-    case SOCK_STREAM:
-        cnx = accept_new_connection(fd, fd_info->collection);
-
-        if (cnx) {
-            add_probing_cnx(fd_info, cnx);
-            new_fd = cnx->q[0].fd;
-        }
-        break;
-
-    case SOCK_DGRAM:
-        new_fd = udp_c2s_forward(fd, fd_info->collection, fd_info->max_fd);
-        fprintf(stderr, "new_fd %d\n", new_fd);
-        if (new_fd == -1)
-            return;
-        break;
-
-    default:
-        log_message(LOG_ERR, "Inconsistent cnx type: %d\n", type);
-        exit(1);
-        return;
-    }
-
-    FD_SET(new_fd, &fd_info->fds_r);
-    if (new_fd >= fd_info->max_fd)
-        fd_info->max_fd = new_fd + 1;
-
-}
-
-/* Check all connections to see if a UDP connections has timed out, then free
- * it. At the same time, keep track of the closest, next timeout. Only do the
- * search through connections if that timeout actually happened. If the
- * connection that would have timed out has had activity, it doesn't matter: we
- * go through connections to find the next timeout, which was needed anyway. */
-static void udp_timeouts(struct select_info* fd_info)
-{
-    time_t now = time(NULL);
-
-    if (now < fd_info->next_timeout) return;
-
-    time_t next_timeout = INT_MAX;
-
-    for (int i = 0; i < fd_info->max_fd; i++) {
-        /* if it's either in read or write set, there is a connection
-         * behind that file descriptor */
-        if (FD_ISSET(i, &fd_info->fds_r) || FD_ISSET(i, &fd_info->fds_w)) {
-            struct connection* cnx = collection_get_cnx_from_fd(fd_info->collection, i);
-            if (cnx) {
-                time_t timeout = udp_timeout(cnx);
-                if (!timeout) continue; /* Not a UDP connection */
-                if (cnx && (timeout <= now)) {
-                    if (cfg.verbose > 3)
-                        fprintf(stderr, "timed out UDP %d\n", cnx->target_sock);
-                    close(cnx->target_sock);
-                    FD_CLR(i, &fd_info->fds_r);
-                    FD_CLR(i, &fd_info->fds_w);
-                    collection_remove_cnx(fd_info->collection, cnx);
-                } else {
-                    if (timeout < next_timeout) next_timeout = timeout;
-                }
-            }
-        }
-    }
-
-    if (next_timeout != INT_MAX)
-        fd_info->next_timeout = next_timeout;
-}
 
 /* Main loop: the idea is as follow:
  * - fds_r and fds_w contain the file descriptors to monitor in read and write
@@ -519,48 +124,42 @@ static void udp_timeouts(struct select_info* fd_info)
  */
 void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
 {
-    struct select_info fd_info = {0};
+    struct loop_info fd_info = {0};
     fd_set readfds, writefds; /* working read and write fd sets */
     struct timeval tv;
     int i, res;
 
     fd_info.num_probing = 0; 
-    FD_ZERO(&fd_info.fds_r);
-    FD_ZERO(&fd_info.fds_w);
     fd_info.probing_list = gap_init(0);
+    udp_init(&fd_info);
+    tcp_init();
 
-    for (i = 0; i < num_addr_listen; i++) {
-        FD_SET(listen_sockets[i].socketfd, &fd_info.fds_r); 
-        set_nonblock(listen_sockets[i].socketfd);
-    }
-    fd_info.max_fd = listen_sockets[num_addr_listen-1].socketfd + 1;
+    watchers_init(&fd_info.watchers, listen_sockets, num_addr_listen);
 
-    fd_info.collection = collection_init(fd_info.max_fd);
+    fd_info.collection = collection_init(fd_info.watchers->max_fd);
 
     while (1)
     {
         memset(&tv, 0, sizeof(tv));
         tv.tv_sec = cfg.timeout;
 
-        memcpy(&readfds, &fd_info.fds_r, sizeof(readfds));
-        memcpy(&writefds, &fd_info.fds_w, sizeof(writefds));
+        memcpy(&readfds, &fd_info.watchers->fds_r, sizeof(readfds));
+        memcpy(&writefds, &fd_info.watchers->fds_w, sizeof(writefds));
 
-        if (cfg.verbose)
-            fprintf(stderr, "selecting... max_fd=%d num_probing=%d\n", 
-                                          fd_info.max_fd, fd_info.num_probing);
-        res = select(fd_info.max_fd, &readfds, &writefds, 
+        print_message(msg_fd, "selecting... max_fd=%d num_probing=%d\n",
+                                          fd_info.watchers->max_fd, fd_info.num_probing);
+        res = select(fd_info.watchers->max_fd, &readfds, &writefds,
                      NULL, fd_info.num_probing ? &tv : NULL);
         if (res < 0)
             perror("select");
 
-
-        /* UDP timeouts: clear out connections after some idle time */
-        udp_timeouts(&fd_info);
-
         /* Check main socket for new connections */
         for (i = 0; i < num_addr_listen; i++) {
             if (FD_ISSET(listen_sockets[i].socketfd, &readfds)) {
-                cnx_accept_process(&fd_info, &listen_sockets[i]);
+                struct connection* new_cnx = cnx_accept_process(&fd_info, &listen_sockets[i]);
+
+                if (fd_out_of_range(new_cnx->q[0].fd))
+                    tidy_connection(new_cnx, &fd_info);
 
                 /* don't also process it as a read socket */
                 FD_CLR(listen_sockets[i].socketfd, &readfds);
@@ -568,8 +167,11 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
         }
 
         /* Check all sockets for write activity */
-        for (i = 0; i < fd_info.max_fd; i++) {
-            if (FD_ISSET(i, &writefds)) {
+        for (i = 0; i < fd_info.watchers->max_fd; i++) {
+            /* Check if it's active AND currently monitored (if a connection
+             * died, it gets tidied, which closes both sockets, but writefs does
+             * not know about that */
+            if (FD_ISSET(i, &writefds) && FD_ISSET(i, &fd_info.watchers->fds_w)) {
                 cnx_write_process(&fd_info, i);
             }
         }
@@ -578,24 +180,23 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
         for (i = 0; i < fd_info.num_probing; i++) {
             struct connection* cnx = gap_get(fd_info.probing_list, i);
             if (!cnx || cnx->state != ST_PROBING) {
-                log_message(LOG_ERR, "Inconsistent probing: cnx=%0xp\n", cnx);
+                print_message(msg_int_error, "Inconsistent probing: cnx=0x%p\n", cnx);
                 if (cnx)
-                    log_message(LOG_ERR, "Inconsistent probing: state=%d\n", cnx);
+                    print_message(msg_int_error, "Inconsistent probing: state=%d\n", cnx->state);
                 exit(1);
             }
             if (cnx->probe_timeout < time(NULL)) {
-                if (cfg.verbose)
-                    fprintf(stderr, "timeout slot %d\n", i);
+                print_message(msg_fd, "timeout slot %d\n", i);
                 probing_read_process(cnx, &fd_info);
             }
         }
 
         /* Check all sockets for read activity */
-        for (i = 0; i < fd_info.max_fd; i++) {
+        for (i = 0; i < fd_info.watchers->max_fd; i++) {
             /* Check if it's active AND currently monitored (if a connection
              * died, it gets tidied, which closes both sockets, but readfs does
              * not know about that */
-            if (FD_ISSET(i, &readfds) && FD_ISSET(i, &fd_info.fds_r)) {
+            if (FD_ISSET(i, &readfds) && FD_ISSET(i, &fd_info.watchers->fds_r)) {
                 cnx_read_process(&fd_info, i);
             }
         }
@@ -604,7 +205,7 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
 
 
 void start_shoveler(int listen_socket) {
-    fprintf(stderr, "inetd mode is not supported in select mode\n");
+    print_message(msg_config_error, "inetd mode is not supported in select mode\n");
     exit(1);
 }
 

sslhconf.cfg

@@ -25,7 +25,31 @@ config: {
          name : "sslhcfg",
          type: "list",
          items: (
-            { name: "verbose"; type: "int"; default: 0; short: "v"; },
+            { name: "verbose-config"; type: "int"; default: 0; 
+                description: "Print configuration at startup" },
+            { name: "verbose-config-error"; type: "int"; default: 3; 
+                description: "Print configuration errors" },
+            { name: "verbose-connections"; type: "int"; default: 3; 
+                description: "Trace established incoming address to forward address" },
+            { name: "verbose-connections-try"; type: "int"; default: 0; 
+                description: "Connection errors" },
+            { name: "verbose-connections-error"; type: "int"; default: 3; 
+                description: "Connection attempts towards targets" },
+            { name: "verbose-fd"; type: "int"; default: 0; 
+                description: "File descriptor activity, open/close/whatnot" },
+            { name: "verbose-packets"; type: "int"; default: 0; 
+                description: "Hexdump packets on which probing is done" },
+
+            { name: "verbose-probe-info"; type: "int"; default: 0; 
+                description: "Trace the probe process" },
+            { name: "verbose-probe-error"; type: "int"; default: 3; 
+                description: "Failures and problems during probing" },
+
+            { name: "verbose-system-error"; type: "int"; default: 3; 
+                description: "System call failures" },
+            { name: "verbose-int-error"; type: "int"; default: 3; 
+                description: "Internal errors that should never happen" },
+
             { name: "version"; type: "bool"; default: false;
               short: "V";
               description: "Print version information and exit"; },
@@ -43,6 +67,8 @@ config: {
             { name: "timeout"; type: "int"; default: 5; 
               short: "t";
               description: "Set up timeout before connecting to default target"; },
+            { name: "udp_max_connections"; type: "int"; default: 1024;
+              description: "Number of concurrent UDP connections"; },
             { name: "user"; type: "string"; optional: true; 
               short: "u";
               description: "Username to change to after set-up"; },
@@ -54,6 +80,8 @@ config: {
               description: "Root to change to after set-up"; },
             { name: "syslog_facility"; type: "string"; default: "auth"; 
               description: "Facility to syslog to"; },
+            { name: "logfile"; type: "string"; optional: true;
+              description: "Log messages to a file" },
 
             { name: "on-timeout"; type: "string"; default: "ssh"; 
               description: "Target to connect to when timing out"; },
@@ -84,8 +112,10 @@ config: {
                     { name: "fork"; type: "bool"; default: false },
                     { name: "tfo_ok"; type: "bool"; default: false;
                         description: "Set to true if this protocol supports TCP FAST OPEN" },
-                    { name: "transparent"; type: "bool"; default: false; 
+                    { name: "transparent"; type: "bool"; default: false;
                         description: "Set to proxy this protocol transparently" },
+                    { name: "resolve_on_forward"; type: "bool"; default: false;
+                        description: "Set to true if server address should be resolved on (every) newly incoming connection (again)" },
                     { name: "log_level"; type: "int"; default: 1 },
                     { name: "keepalive"; type: "bool"; default: false },
                     { name: "sni_hostnames",
@@ -105,7 +135,8 @@ config: {
                     # Runtime data
                     { name: "probe"; type: "runtime"; c_type: "T_PROBE*" },
                     { name: "saddr"; type: "runtime"; c_type: "struct addrinfo*" },
-                    { name: "data"; type: "runtime"; c_type: "void*" }
+                    { name: "data"; type: "runtime"; c_type: "void*" },
+                    { name: "timeouts"; type: "runtime"; c_type: "dl_list" }
                 )
             }
         )
@@ -155,6 +186,19 @@ cl_groups: (
         { path: "tfo_ok"; value: 1 }
         );
     },
+    # Redundant with the --tls setting before, for backwards compatibility
+    { name: "ssl"; pattern: "(.+):(\w+)"; description: "Set up TLS/SSL target";
+        list: "protocols";
+        override: "name";
+        argdesc: "<host:port>";
+        targets: (
+        { path: "name"; value: "tls" },
+        { path: "host"; value: "$1" },
+        { path: "port"; value: "$2" },
+        { path: "log_level"; value: 1 },
+        { path: "tfo_ok"; value: 1 }
+        );
+    },
     { name: "openvpn"; pattern: "(.+):(\w+)"; description: "Set up OpenVPN target";
         list: "protocols";
         override: "name";
@@ -179,6 +223,18 @@ cl_groups: (
         { path: "tfo_ok"; value: 1 }
         );
     },
+    { name: "wireguard"; pattern: "(.+):(\w+)"; description: "Set up WireGuard target";
+        list: "protocols";
+        override: "name";
+        argdesc: "<host:port>";
+        targets: (
+        { path: "name"; value: "wireguard" },
+        { path: "host"; value: "$1" },
+        { path: "port"; value: "$2" },
+        { path: "log_level"; value: 1 },
+        { path: "tfo_ok"; value: 1 }
+        );
+    },
     { name: "xmpp"; pattern: "(.+):(\w+)"; description: "Set up XMPP target";
         list: "protocols";
         override: "name";
@@ -234,6 +290,17 @@ cl_groups: (
         { path: "log_level"; value: 1 }
         );
     },
+    { name: "msrdp"; pattern: "(.+):(\w+)"; description: "Set up msrdp target";
+        list: "protocols";
+        override: "name";
+        argdesc: "<host:port>";
+        targets: (
+        { path: "name"; value: "msrdp" },
+        { path: "host"; value: "$1" },
+        { path: "port"; value: "$2" },
+        { path: "log_level"; value: 1 }
+        );
+    },
     { name: "anyprot"; pattern: "(.+):(\w+)"; description: "Set up default target";
         list: "protocols";
         override: "name";

systemd-sslh-generator.c

@@ -1,37 +1,72 @@
 #include <libconfig.h>
+#include <dirent.h>
 #include <stdio.h>
+#include <errno.h>
 #include <string.h>
 #include <stdlib.h>
+#include <stdbool.h>
+#include <stdarg.h>
+#include <sys/stat.h>
 #include "common.h"
 
 
-static char* resolve_listen(const char *hostname, const char *port) {
-    /* Need room in the strcat for \0 and :
-     * the format in the socket unit file is hostname:port */
-    char *conn = malloc(strlen(hostname)+strlen(port)+2);
-    CHECK_ALLOC(conn, "malloc");
+#define print_message(sink, format, file, line) fprintf(stderr, format, file, line)                                                                                                                                               
+
+typedef struct FileList FileList;
+
+struct FileList {
+    char *name;
+    struct FileList *prev;
+};
+
+static void free_file_list(FileList *fl) {
+    while (fl != NULL) {
+        FileList *prev = fl->prev;
+        free(fl->name);
+        free(fl);
+        fl = prev;
+    }
+}
+
+static FILE *err_log;
+static bool systemd_invoked = false;
+static const char
+        *socket_ext = ".socket",
+        *dropin_ext = ".conf",
+        *service_ext = ".service.d/",
+        *fork_unit_file = "/sslh@",
+        *select_unit_file = "/sslh-select@",
+        *fork_unit = "# Automatically generated by systemd-sslh-generator\n\n"
+                     "[Unit]\n"
+                     "Requires=sslh@%s.socket\n"
+                     "Conflicts=sslh-select@%s.service\n"
+                     "PartOf=sslh@%s.socket\n",
+        *select_unit = "# Automatically generated by systemd-sslh-generator\n\n"
+                       "[Unit]\n"
+                       "Requires=sslh@%s.socket\n"
+                       "Conflicts=sslh@%s.service\n"
+                       "PartOf=sslh@%s.socket\n";
+
+static char *resolve_listen(const char *hostname, const char *port) {
+    char *conn = calloc(1, strlen(hostname) + strlen(port) + 2);
+    CHECK_ALLOC(conn, "malloc")
     strcpy(conn, hostname);
     strcat(conn, ":");
     strcat(conn, port);
-
     return conn;
-
 }
 
-
 static int get_listen_from_conf(const char *filename, char **listen[]) {
     config_t config;
     config_setting_t *setting, *addr;
     const char *hostname, *port;
     int len = 0;
 
-    /* look up the listen stanzas in the config file so these
-     * can be used in the socket file generated */
     config_init(&config);
     if (config_read_file(&config, filename) == CONFIG_FALSE) {
-        /* we don't care if file is missing, skip it */
         if (config_error_line(&config) != 0) {
-            fprintf(stderr, "%s:%d:%s\n",
+            fprintf(err_log,
+                    "systemd-sslh-generator: %s%d%s\n",
                     filename,
                     config_error_line(&config),
                     config_error_text(&config));
@@ -40,114 +75,247 @@ static int get_listen_from_conf(const char *filename, char **listen[]) {
     } else {
         setting = config_lookup(&config, "listen");
         if (setting) {
-	    int i;
             len = config_setting_length(setting);
             *listen = malloc(len * sizeof(**listen));
-            CHECK_ALLOC(*listen, "malloc");
-            for (i = 0; i < len; i++) {
+            CHECK_ALLOC(*listen, "malloc")
+            for (int i = 0; i < len; i++) {
                 addr = config_setting_get_elem(setting, i);
-                if (! (config_setting_lookup_string(addr, "host", &hostname) &&
-                       config_setting_lookup_string(addr, "port", &port))) {
-                    fprintf(stderr,
-                            "line %d:Incomplete specification (hostname and port required)\n",
+                if (!(config_setting_lookup_string(addr, "host", &hostname) && config_setting_lookup_string(addr, "port", &port))) {
+                    fprintf(err_log,
+                            "systemd-sslh-generator: line %d:Incomplete specification (hostname and port required)\n",
                             config_setting_source_line(addr));
                     return -1;
                 } else {
-                    (*listen)[i] = malloc(strlen(resolve_listen(hostname, port)));
-                    CHECK_ALLOC((*listen)[i], "malloc");
-                    strcpy((*listen)[i], resolve_listen(hostname, port));
+                    (*listen)[i] = resolve_listen(hostname, port);
                 }
             }
         }
     }
-
     return len;
-
 }
 
-static int write_socket_unit(FILE *socket, char *listen[], int num_addr, const char *source) {
-    int i;
-
+static void write_socket_unit(FILE *socket, char *listen[], int num_addr, const char *cfg, const char *source) {
     fprintf(socket,
             "# Automatically generated by systemd-sslh-generator\n\n"
             "[Unit]\n"
-            "Before=sslh.service\n"
+            "Before=sslh@%s.service\n"
             "SourcePath=%s\n"
+            "PartOf=sslh@%s.service\n"
             "Documentation=man:sslh(8) man:systemd-sslh-generator(8)\n\n"
             "[Socket]\n"
             "FreeBind=true\n",
-            source);
-
-    for (i = 0; i < num_addr; i++) {
+            cfg,
+            source,
+            cfg);
+    for (int i = 0; i < num_addr; i++) {
         fprintf(socket, "ListenStream=%s\n", listen[i]);
     }
+    fprintf(socket,
+           "\n[Install]\n"
+           "WantedBy=sockets.target\n");
+}
 
+static int write_unit_dropin(const char *runtime_unit_dir, const bool is_fork, const char *cfg) {
+    const char
+        *unit_file = is_fork ? fork_unit_file : select_unit_file,
+        *unit_string = is_fork ? fork_unit : select_unit;
+    FILE *dropin_fd = stdout;
+    if (systemd_invoked) {
+        //Systemd drop-in configuration for the base select service sslh@%I.service
+        const size_t runtime_len = strlen(runtime_unit_dir);
+        size_t len = strlen(unit_file) + strlen(cfg) + strlen(service_ext) + strlen(dropin_ext);
+        char dropin_dir[runtime_len + len + 1];
+        strcpy(dropin_dir, runtime_unit_dir);
+        strcat(dropin_dir, unit_file);
+        strcat(dropin_dir, cfg);
+        strcat(dropin_dir, service_ext);
+
+        if (mkdir(dropin_dir, S_IRWXU | S_IRWXG | S_IROTH)) {
+            fprintf(err_log,
+                    "systemd-sslh-generator: Could not create directory '%s' to generate drop-in configuration: %s\n",
+                    dropin_dir,
+                    strerror(errno));
+            return errno;
+        }
+
+        len = len + strlen(cfg) + strlen(dropin_ext);
+        char dropin_path[len + 1];
+        strcpy(dropin_path, dropin_dir);
+        strcat(dropin_path, cfg);
+        strcat(dropin_path, dropin_ext);
+        dropin_fd = fopen(dropin_path, "w");
+        if (!dropin_fd) {
+            fprintf(err_log,
+                    "systemd-sslh-generator: Could not open '%s' to generate drop-in configuration: %s\n",
+                    dropin_path,
+                    strerror(errno));
+            return errno;
+        }
+    }
+    fprintf(dropin_fd, unit_string, cfg, cfg, cfg);
+    if (systemd_invoked) {
+        fclose(dropin_fd);
+    }
     return 0;
 }
 
 static int gen_sslh_config(char *runtime_unit_dir) {
-    char *sslh_conf;
-    int num_addr;
-    FILE *config;
+    int status = 0;
+    const char *config_dir = "/etc/sslh/";
     char **listen;
-    FILE *runtime_conf_fd = stdout;
-    const char *unit_file;
+    DIR *d = opendir(config_dir);
+    FileList *fa = NULL;
 
-    /* There are two default locations so check both with first given preference */
-    sslh_conf = "/etc/sslh.cfg";
-
-    config = fopen(sslh_conf, "r");
-    if (config  == NULL) {
-        sslh_conf="/etc/sslh/sslh.cfg";
-        config = fopen(sslh_conf, "r");
-        if (config == NULL) {
-            return -1;
+    if (d) {
+        struct dirent *dir;
+        while ((dir = readdir(d)) != NULL) {
+            if ((strcmp(dir->d_name, ".") == 0) || (strcmp(dir->d_name, "..") == 0)) {
+                continue;
+            }
+            FileList *lfa = malloc(sizeof(FileList));
+            CHECK_ALLOC(lfa, "malloc")
+            lfa->name = malloc(strlen(dir->d_name) + 1);
+            CHECK_ALLOC(lfa->name, "malloc")
+            strcpy(lfa->name, dir->d_name);
+            lfa->prev = NULL;
+            if (fa) {
+                lfa->prev = fa;
+            }
+            fa = lfa;
         }
+        closedir(d);
+    } else {
+        fprintf(err_log,
+                "systemd-sslh-generator: Configuration directory '/etc/sslh/' does not exist! No units generated.\n");
+        //Config directory /etc/sslh/ does not exist
+        return 0;
     }
-
-    fclose(config);
-
-    num_addr = get_listen_from_conf(sslh_conf, &listen);
-    if (num_addr < 0)
-        return -1;
-
-    /* If this is run by systemd directly write to the location told to
-     * otherwise write to standard out so that it's trivial to check what
-     * will be written */
-    if (runtime_unit_dir && *runtime_unit_dir) {
-        unit_file = "/sslh.socket";
-        size_t uf_len = strlen(unit_file);
-        size_t runtime_len = strlen(runtime_unit_dir) + uf_len + 1;
-        char *runtime_conf = malloc(runtime_len);
-        CHECK_ALLOC(runtime_conf, "malloc");
-        strcpy(runtime_conf, runtime_unit_dir);
-        strcat(runtime_conf, unit_file);
-        runtime_conf_fd = fopen(runtime_conf, "w");
+    if (!fa) {
+        fprintf(err_log,
+                "systemd-sslh-generator: Configuration directory '/etc/sslh/' is empty! No units generated.\n");
+        //No configuration files in /etc/sslh/
+        return 0;
     }
+    FileList *fa_ref = fa;
+//    size_t num_listen_addresses = 0;
+//    char **listen_addresses = NULL;
+    //Process all config files
+    do {
+        char *end = strstr(fa->name, ".cfg");
+        if (!end) {
+            continue;
+        }
+        //Current sslh config name
+        const size_t end_count = end - fa->name;
+        char config_name[end_count + 1];
+        memcpy(config_name, fa->name, end_count);
+        config_name[end_count] = '\0';
 
-
-    return write_socket_unit(runtime_conf_fd, listen, num_addr, sslh_conf);
+        //Full path to current sslh config
+        char full_path[strlen(config_dir) + strlen(fa->name) + 1];
+        strcpy(full_path, config_dir);
+        strcat(full_path, fa->name);
+        FILE *config = fopen(full_path, "r");
+        if (!config) {
+            fprintf(err_log,
+                    "systemd-sslh-generator: Could not open config file '%s': %s\n",
+                    full_path,
+                    strerror(errno));
+            return errno;
+        } else {
+            fclose(config);
+            int num_addr = get_listen_from_conf(full_path, &listen);
+            if (num_addr <= 0) {
+                fprintf(err_log,
+                        "systemd-sslh-generator: sslh config '%s' contains no valid listen configurations!\n",
+                        fa->name);
+                status |= -1;
+                continue;
+            }
+            FILE *socket_fd = stdout;
+            if (systemd_invoked) {
+                //Systemd socket for the current sslh config
+                const size_t len = strlen(runtime_unit_dir) + strlen(fork_unit_file) + strlen(config_name) + strlen(socket_ext);
+                char socket_path[len + 1];
+                strcpy(socket_path, runtime_unit_dir);
+                strcat(socket_path, fork_unit_file);
+                strcat(socket_path, config_name);
+                strcat(socket_path, socket_ext);
+                socket_fd = fopen(socket_path, "w");
+                if (!socket_fd) {
+                    fprintf(err_log,
+                            "systemd-sslh-generator: Could not open '%s' to generate socket configuration: %s\n",
+                            socket_path,
+                            strerror(errno));
+                    status |= errno;
+                    continue;
+                }
+            }
+            //Write socket unit
+            write_socket_unit(socket_fd, listen, num_addr, config_name, full_path);
+            //Write forking drop-in config
+            status |= write_unit_dropin(runtime_unit_dir, false, config_name);
+            //Write select drop-in config
+            status |= write_unit_dropin(runtime_unit_dir, true, config_name);
+            if (systemd_invoked) {
+                fclose(socket_fd);
+            }
+//            if (listen_addresses) {
+//                //Check for overlapping addresses
+//                for (size_t i = 0; i < num_listen_addresses; i++) {
+//                    for (size_t j = 0; j < num_addr; j++) {
+//                        if (strcmp(*(listen_addresses + i), *(listen + j)) == 0) {
+//                            fprintf(err_log, "systemd-sslh-generator: Overlapping listen addresses across sslh configurations!");
+//                            return -1;
+//                        }
+//                    }
+//                }
+//            }
+//            char *listen_addresses_copy[num_listen_addresses + num_addr];
+//            if (listen_addresses) {
+//                //Copy previous configurations' listen addresses into temp
+//                memcpy(listen_addresses_copy, listen_addresses, num_listen_addresses);
+//                //Free global list of listen addresses
+//                free(listen_addresses);
+//            }
+//            //Copy listen addresses from current configuration into temp
+//            memcpy(listen_addresses_copy + num_listen_addresses, listen, num_addr);
+//            num_listen_addresses += num_addr;
+//            listen_addresses = malloc(num_listen_addresses * sizeof(char *));
+//            CHECK_ALLOC(listen_addresses, "malloc")
+//            //Append all addresses to global list
+//            memcpy(listen_addresses, listen_addresses_copy, num_listen_addresses);
+            //Free all allocated listen strings
+            for (size_t i = 0; i < num_addr; i++) {
+                free(*(listen + i));
+            }
+        }
+    } while((fa = fa->prev));
+    free_file_list(fa_ref);
+    return status;
 }
 
-
-int main(int argc, char *argv[]){
-    int r = 0;
-    int k;
-    char *runtime_unit_dest = "";
-
-    if (argc > 1 && (argc != 4) ) {
+int main(int argc, char *argv[]) {
+    if (argc == 1 || argc == 4) {
+        systemd_invoked = argc == 4;
+        if (systemd_invoked) {
+            err_log = fopen("/dev/kmsg", "w");
+            if (!err_log) {
+                return -1;
+            }
+        } else {
+            err_log = stderr;
+        }
+        const int r = gen_sslh_config(systemd_invoked ? argv[1] : "");
+        if (systemd_invoked) {
+            fclose(err_log);
+        }
+        if (!r) {
+            fprintf(err_log, "systemd-sslh-generator: Successfully generated all targets.\n");
+        }
+        return r < 0 ? -1 : 0;
+    } else {
         printf("This program takes three or no arguments.\n");
         return -1;
     }
-
-    if (argc  > 1)
-        runtime_unit_dest = argv[1];
-
-    k = gen_sslh_config(runtime_unit_dest);
-    if (k < 0)
-        r = k;
-
-    return r < 0 ? -1 : 0;
 }
-
-

t

@@ -396,7 +396,7 @@ if ($RB_RESOLVE_ADDRESS) {
     my $sslh_pid;
     if (!($sslh_pid = fork)) {
         my $user = (getpwuid $<)[0]; # Run under current username
-        exec "./sslh-select -v 3 -f -u $user --listen blahblah.dontexist:9000 --ssh $ssh_address --tls $ssl_address -P $pidfile";
+        exec "./sslh-select -v 3 -f -u $user --listen blahblah.nonexistent:9000 --ssh $ssh_address --tls $ssl_address -P $pidfile";
     }
     warn "spawned $sslh_pid\n";
     waitpid $sslh_pid, 0;

t_load

@@ -14,13 +14,13 @@
 use strict;
 use IO::Socket::INET6;
 use Data::Dumper;
-use Conf::Libconfig;
+use Conf::Libconfig 1.0.3;
 
 ## BEGIN TEST CONFIG
 
 # How many total clients to we start? Each client will pick
 # a new protocol among what's in test.cfg.
-my $NUM_CNX = 50;
+my $NUM_CNX = 16;
 
 # Delay between starting new processes when starting up. If
 # you start 200 processes in under a second, things go wrong
@@ -35,7 +35,7 @@ my $block_rpt = 5;
 # Probability to stop a client after a message (e.g. with
 # .01 a client will send an average of 100 messages before
 # disconnecting).
-my $stop_client_probability = .001;
+my $stop_client_probability = .0001;
 
 ##END CONFIG
 
@@ -44,7 +44,7 @@ $conf->read_file("test.cfg");
 
 
 # Pick one address for TCP and one for UDP
-my @listen = @{$conf->fetch_array("listen")};
+my @listen = @{$conf->value("listen")};
 my ($sslh_tcp_address, $sslh_udp_address);
 
 foreach my $l (@listen) {
@@ -65,7 +65,7 @@ my %connect_params = (
         test_data => "foo bar",
         resp_len => 12,
     },
-        ssh => {
+    ssh => {
         sleep => 20,  # So it times out 50% of connections
         test_data => "SSH-2.0 hello",
         resp_len => 18,  # length "ssh: SSH-2.0 hello" => 18
@@ -73,7 +73,7 @@ my %connect_params = (
     tinc => {
         sleep => 0,
         test_data => "0 ",
-        resp_len => 8, # length "tinc: 0 " => 10 
+        resp_len => 8, # length "tinc: 0 " => 10
     },
     openvpn => {
         sleep => 0,
@@ -186,7 +186,7 @@ sub udp_client {
     }
 }
 
-foreach my $p (@{$conf->fetch_array("protocols")}) {
+foreach my $p (@{$conf->value("protocols")}) {
     if (!fork) {
         my $udp = $p->{is_udp} ? "--udp" : "";
         my $cmd = "./echosrv $udp -p $p->{host}:$p->{port} --prefix '$p->{name}: ' 2> /dev/null";
@@ -203,7 +203,7 @@ sleep 2; # Let echosrv's and sslh start
 my ($c_in, $c_out);
 pipe $c_in, $c_out;
 
-my @protocols = @{$conf->fetch_array("protocols")};
+my @protocols = @{$conf->value("protocols")};
 
 if (!fork) {
     # Process that starts all the clients

tcp-listener.c

@@ -0,0 +1,333 @@
+/*
+   tcp-listener.c: handles demultiplexing TCP protocols
+
+# Copyright (C) 2022  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+
+*/
+
+#include <errno.h>
+#include "tcp-listener.h"
+#include "probe.h"
+#include "log.h"
+
+/* Removes cnx from probing list */
+static void remove_probing_cnx(struct loop_info* fd_info, struct connection* cnx)
+{
+    gap_remove_ptr(fd_info->probing_list, cnx, fd_info->num_probing);
+    fd_info->num_probing--;
+}
+
+static void add_probing_cnx(struct loop_info* fd_info, struct connection* cnx)
+{
+    gap_set(fd_info->probing_list, fd_info->num_probing, cnx);
+    fd_info->num_probing++;
+}
+
+/* shovels data from active fd to the other
+   returns after one socket closed or operation would block
+ */
+static void shovel(struct connection *cnx, int active_fd, struct loop_info* fd_info)
+{
+    struct queue *read_q, *write_q;
+
+    read_q = &cnx->q[active_fd];
+    write_q = &cnx->q[1-active_fd];
+
+    print_message(msg_fd, "activity on fd%d\n", read_q->fd);
+
+    switch(fd2fd(write_q, read_q)) {
+    case -1:
+    case FD_CNXCLOSED:
+        tidy_connection(cnx, fd_info);
+        break;
+
+    case FD_STALLED:
+        watchers_add_write(fd_info->watchers, write_q->fd);
+        watchers_del_read(fd_info->watchers, read_q->fd);
+        break;
+
+    default: /* Nothing */
+        break;
+    }
+}
+
+
+/* Returns the queue index that contains the specified file descriptor.
+ * This is called by the *_process functions, which got cnx from the fd, so it
+ * is impossible for fd to not be cnx, hence we die if it happens */
+static int active_queue(struct connection* cnx, int fd)
+{
+    if (cnx->q[0].fd == fd) return 0;
+    if (cnx->q[1].fd == fd) return 1;
+
+    print_message(msg_int_error, "file descriptor %d not found in connection object\n", fd);
+    exit(1);
+}
+
+/* Process a TCP read event on the specified file descriptor */
+void tcp_read_process(struct loop_info* fd_info,
+                             int fd)
+{
+    cnx_collection* collection = fd_info->collection;
+    struct connection* cnx = collection_get_cnx_from_fd(collection, fd);
+
+    /* connection can get tidied if there is an error on the other file
+     * descriptor -- then cnx is NULL */
+    if (!cnx) return;
+
+    /* Determine active queue (0 or 1): if fd is that of q[1], active_q = 1,
+     * otherwise it's 0 */
+    int active_q = active_queue(cnx, fd);
+
+    switch (cnx->state) {
+
+    case ST_PROBING:
+        if (active_q == 1) {
+            print_message(msg_int_error, "Activity on fd2 while probing, impossible\n");
+            dump_connection(cnx);
+            exit(1);
+        }
+
+        probing_read_process(cnx, fd_info);
+
+        break;
+
+    case ST_SHOVELING:
+        shovel(cnx, active_q, fd_info);
+        break;
+
+    default: /* illegal */
+        print_message(msg_int_error, "Illegal connection state %d\n", cnx->state);
+        dump_connection(cnx);
+        exit(1);
+    }
+}
+
+/* Accepts a connection from the main socket and assigns it to an empty slot.
+ * If no slots are available, allocate another few. If that fails, drop the
+ * connexion */
+struct connection* accept_new_connection(int listen_socket, struct loop_info* fd_info)
+{
+    int in_socket, res;
+
+    print_message(msg_fd, "accepting from %d\n", listen_socket);
+
+    in_socket = accept(listen_socket, 0, 0);
+    CHECK_RES_RETURN(in_socket, "accept", NULL);
+
+    res = set_nonblock(in_socket);
+    if (res == -1) {
+        close(in_socket);
+        return NULL;
+    }
+
+    struct connection* cnx = collection_alloc_cnx_from_fd(fd_info->collection, in_socket);
+    if (!cnx) {
+        close(in_socket);
+        return NULL;
+    }
+
+    add_probing_cnx(fd_info, cnx);
+    return cnx;
+}
+
+
+/* Connect queue 1 of connection to SSL; returns new file descriptor */
+static int connect_queue(struct connection* cnx,
+                         struct loop_info* fd_info)
+{
+    struct queue *q = &cnx->q[1];
+
+    q->fd = connect_addr(cnx, cnx->q[0].fd, NON_BLOCKING);
+    if (q->fd != -1) {
+        log_connection(NULL, cnx);
+        flush_deferred(q);
+        if (q->deferred_data) {
+            watchers_add_write(fd_info->watchers, q->fd);
+            watchers_del_read(fd_info->watchers, cnx->q[0].fd);
+        }
+        watchers_add_read(fd_info->watchers, q->fd);
+        collection_add_fd(fd_info->collection, cnx, q->fd);
+        return q->fd;
+    } else {
+        tidy_connection(cnx, fd_info);
+        return -1;
+    }
+}
+
+/* shovels data from one fd to the other and vice-versa
+   returns after one socket closed
+ */
+static void shovel_single(struct connection *cnx)
+{
+   fd_set fds_r, fds_w;
+   int res, i;
+   int max_fd = MAX(cnx->q[0].fd, cnx->q[1].fd) + 1;
+
+   FD_ZERO(&fds_r);
+   FD_ZERO(&fds_w);
+   while (1) {
+      for (i = 0; i < 2; i++) {
+         if (cnx->q[i].deferred_data_size) {
+            FD_SET(cnx->q[i].fd, &fds_w);
+            FD_CLR(cnx->q[1-i].fd, &fds_r);
+         } else {
+            FD_CLR(cnx->q[i].fd, &fds_w);
+            FD_SET(cnx->q[1-i].fd, &fds_r);
+         }
+      }
+
+      res = select(
+                   max_fd,
+                   &fds_r,
+                   &fds_w,
+                   NULL,
+                   NULL
+                  );
+      CHECK_RES_DIE(res, "select");
+
+      for (i = 0; i < 2; i++) {
+          if (FD_ISSET(cnx->q[i].fd, &fds_w)) {
+              res = flush_deferred(&cnx->q[i]);
+              if ((res == -1) && ((errno == EPIPE) || (errno == ECONNRESET))) {
+                  print_message(msg_fd, "%s socket closed\n", i ? "server" : "client");
+                  return;
+              }
+          }
+          if (FD_ISSET(cnx->q[i].fd, &fds_r)) {
+              res = fd2fd(&cnx->q[1-i], &cnx->q[i]);
+              if (!res) {
+                  print_message(msg_fd, "socket closed\n");
+                  return;
+              }
+          }
+      }
+   }
+}
+
+
+
+/* Child process that makes internal connection and proxies
+ */
+static void connect_proxy(struct connection *cnx)
+{
+    int in_socket;
+    int out_socket;
+
+    /* Minimize the file descriptor value to help select() */
+    in_socket = dup(cnx->q[0].fd);
+    if (in_socket == -1) {
+        in_socket = cnx->q[0].fd;
+    } else {
+        close(cnx->q[0].fd);
+        cnx->q[0].fd = in_socket;
+    }
+
+    /* Connect the target socket */
+    out_socket = connect_addr(cnx, in_socket, BLOCKING);
+    CHECK_RES_DIE(out_socket, "connect");
+
+    cnx->q[1].fd = out_socket;
+
+    log_connection(NULL, cnx);
+
+    shovel_single(cnx);
+
+    close(in_socket);
+    close(out_socket);
+
+    print_message(msg_fd, "connection closed down\n");
+
+    exit(0);
+}
+
+/* Process read activity on a socket in probe state 
+ * IN/OUT cnx: connection data, updated if connected
+ * IN/OUT info: updated if connected
+ * */
+void probing_read_process(struct connection* cnx,
+                                 struct loop_info* fd_info)
+{
+    int res;
+
+    /* If timed out it's SSH, otherwise the client sent
+     * data so probe the protocol */
+    if ((cnx->probe_timeout < time(NULL))) {
+        cnx->proto = timeout_protocol();
+        print_message(msg_fd, "timed out, connect to %s\n", cnx->proto->name);
+    } else {
+        res = probe_client_protocol(cnx);
+        if (res == PROBE_AGAIN)
+            return;
+    }
+
+    remove_probing_cnx(fd_info, cnx);
+    cnx->state = ST_SHOVELING;
+
+    /* libwrap check if required for this protocol */
+    if (cnx->proto->service &&
+        check_access_rights(cnx->q[0].fd, cnx->proto->service)) {
+        tidy_connection(cnx, fd_info);
+        res = -1;
+    } else if (cnx->proto->fork) {
+        switch (fork()) {
+        case 0:  /* child */
+            /* TODO: close all file descriptors except 2 */
+            /* free(cnx); */
+            connect_proxy(cnx);
+            exit(0);
+        case -1: print_message(msg_system_error, "fork failed: err %d: %s\n", errno, strerror(errno));
+                 break;
+        default: /* parent */
+                 break;
+        }
+        tidy_connection(cnx, fd_info);
+        res = -1;
+    } else {
+        res = connect_queue(cnx, fd_info);
+    }
+}
+
+
+/* Process a connection that is active in write (this is TCP only, as
+ * UDP sockets are never "full" or deferred or whatever) */
+void cnx_write_process(struct loop_info* fd_info, int fd)
+{
+    struct connection* cnx = collection_get_cnx_from_fd(fd_info->collection, fd);
+
+    /* connection can get tidied if there is an error on the other file
+     * descriptor -- then cnx is NULL */
+    if (!cnx) return;
+
+    int res;
+    int queue = active_queue(cnx, fd);
+
+    res = flush_deferred(&cnx->q[queue]);
+    if ((res == -1) && ((errno == EPIPE) || (errno == ECONNRESET))) {
+        if (cnx->state == ST_PROBING) remove_probing_cnx(fd_info, cnx);
+        tidy_connection(cnx, fd_info);
+    } else {
+        /* If no deferred data is left, stop monitoring the fd 
+         * for write, and restart monitoring the other one for reads*/
+        if (!cnx->q[queue].deferred_data_size) {
+            watchers_del_write(fd_info->watchers, cnx->q[queue].fd);
+            watchers_add_read(fd_info->watchers, cnx->q[1-queue].fd);
+        }
+    }
+}
+

tcp-listener.h

@@ -0,0 +1,13 @@
+#ifndef TCP_LISTENER_H
+#define TCP_LISTENER_H
+
+#include "processes.h"
+#include "collection.h"
+#include "tcp-probe.h"
+
+void tcp_read_process(struct loop_info* fd_info, int fd);
+struct connection* accept_new_connection(int listen_socket, struct loop_info* fd_info);
+void probing_read_process(struct connection* cnx, struct loop_info* fd_info);
+void cnx_write_process(struct loop_info* fd_info, int fd);
+
+#endif

tcp-probe.c

@@ -0,0 +1,99 @@
+/*
+# tcp-probe.c: TCP code that is common to the sslh-fork and sslh-[ev|select] 
+#
+# Copyright (C) 2022  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+*/
+
+
+#include "probe.h"
+
+static struct sslhcfg_protocols_item** tcp_protocols;
+static int tcp_protocols_len = 0;
+
+/*
+ * Read the beginning of data coming from the client connection and check if
+ * it's a known protocol.
+ * Return PROBE_AGAIN if not enough data, or PROBE_MATCH if it succeeded in
+ * which case cnx->proto is set to the appropriate protocol.
+ */
+int probe_client_protocol(struct connection *cnx)
+{
+    char buffer[BUFSIZ];
+    ssize_t n;
+
+    n = read(cnx->q[0].fd, buffer, sizeof(buffer));
+    /* It's possible that read() returns an error, e.g. if the client
+     * disconnected between the previous call to select() and now. If that
+     * happens, we just connect to the default protocol so the caller of this
+     * function does not have to deal with a specific  failure condition (the
+     * connection will just fail later normally). */
+
+    if (n > 0) {
+        defer_write(&cnx->q[1], buffer, n);
+        return probe_buffer(cnx->q[1].begin_deferred_data,
+                            cnx->q[1].deferred_data_size,
+                            tcp_protocols, tcp_protocols_len,
+                            &cnx->proto
+                            );
+    }
+
+    /* read() returned an error, so just connect to the last protocol to die */
+    cnx->proto = &cfg.protocols[cfg.protocols_len-1];
+    return PROBE_MATCH;
+}
+
+
+static void tcp_protocol_list_init(void)
+{
+    tcp_protocols = calloc(cfg.protocols_len, sizeof(tcp_protocols));
+    CHECK_ALLOC(tcp_protocols, "tcp_protocols");
+    for (int i = 0; i < cfg.protocols_len; i++) {
+        struct sslhcfg_protocols_item* p = &cfg.protocols[i];
+        if (!p->is_udp) {
+            tcp_protocols[tcp_protocols_len] = p;
+            tcp_protocols_len++;
+        }
+    }
+}
+
+/* Configuration sanity check for TCP:
+ * - If there is a listening socket, there must be at least one target
+ */
+static void tcp_sanity_check(void)
+{
+    int tcp_present = 0;
+
+    for (int i = 0; i < cfg.listen_len; i++) {
+        struct sslhcfg_listen_item* p = &cfg.listen[i];
+        if (!p->is_udp) {
+            tcp_present = 1;
+            break;
+        }
+    }
+
+    if (tcp_present && !tcp_protocols_len) {
+        print_message(msg_config_error, "At least one TCP target protocol must be specified.\n");
+        exit(2);
+    }
+}
+
+void tcp_init(void)
+{
+    tcp_protocol_list_init();
+    tcp_sanity_check();
+}

tcp-probe.h

@@ -0,0 +1,6 @@
+#ifndef TCP_PROBE_H
+#define TCP_PROBE_H
+
+void tcp_init(void);
+
+#endif

test.cfg

@@ -1,7 +1,6 @@
 # Configuration file for testing (use both by sslh under
 # test and the test script `t`)
 
-verbose: 4;
 foreground: true;
 inetd: false;
 numeric: true;
@@ -11,6 +10,21 @@ pidfile: "/tmp/sslh_test.pid";
 
 syslog_facility: "auth"; 
 
+# Logging configuration
+# Value: 1: stdout; 2: syslog; 3: both
+# Defaults should be sensible. Generally, you want *-error
+# to be always enabled, to know if something is going wrong.
+verbose-config: 1; #  print configuration at startup
+verbose-config-error: 1;  # print configuration errors
+verbose-connections: 1; # trace established incoming address to forward address
+verbose-connections-error: 1; # connection errors
+verbose-connections-try: 1; # connection attempts towards targets
+verbose-fd: 0; # file descriptor activity, open/close/whatnot
+verbose-packets: 1; # hexdump packets on which probing is done
+verbose-probe-info: 0; # what's happening during the probe process
+verbose-probe-error: 1; # failures and problems during probing
+verbose-system-error: 1; # system call problem, i.e.  malloc, fork, failing
+verbose-int-error: 1; # internal errors, the kind that should never happen
 
 # List of interfaces on which we should listen
 # Options:
@@ -21,10 +35,14 @@ listen:
     { host: "ip4-localhost"; is_udp: true; port: "8086"; }
 );
 
+
+# Tester beware: when using fork, the forked process loses
+# track of buffers of other, concurrent connections. Memory
+# leak tools thus complain each time a forked process stops.
  
 protocols:
 (
-     { name: "ssh";  host: "localhost"; port: "9000"; fork: true; transparent: true; },
+     { name: "ssh";  host: "localhost"; port: "9000"; fork: true; transparent: true; resolve_on_forward: true; },
      { name: "socks5";  host: "localhost"; port: "9001";  },
      { name: "http";  host: "localhost"; port: "9002";  },
      { name: "tinc";  host: "localhost"; port: "9003"; },
@@ -35,6 +53,7 @@ protocols:
      { name: "regex"; host: "ip4-localhost"; is_udp: true; port: "9020";
          udp_timeout: 30;
          regex_patterns: [ "^foo" ];
+         resolve_on_forward: true;
      },
      { name: "regex"; host: "localhost"; port: "9011";
         regex_patterns: [ "^foo", "^bar" ];

tls.c

@@ -33,6 +33,7 @@
 #include <fnmatch.h> /* fnmatch() */
 #include "tls.h"
 #include "sslh-conf.h"
+#include "log.h"
 
 #define TLS_HEADER_LEN 5
 #define TLS_HANDSHAKE_CONTENT_TYPE 0x16
@@ -82,14 +83,14 @@ parse_tls_header(const struct TLSProtocol *tls_data, const char *data, size_t da
 
     tls_content_type = data[0];
     if (tls_content_type != TLS_HANDSHAKE_CONTENT_TYPE) {
-        if (cfg.verbose) fprintf(stderr, "Request did not begin with TLS handshake.\n");
+        print_message(msg_probe_info, "Request did not begin with TLS handshake.\n");
         return TLS_EPROTOCOL;
     }
 
     tls_version_major = data[1];
     tls_version_minor = data[2];
     if (tls_version_major < 3) {
-        if (cfg.verbose) fprintf(stderr, "Received SSL %d.%d handshake which cannot be parsed.\n",
+        print_message(msg_probe_error, "Received SSL %d.%d handshake which cannot be parsed.\n",
               tls_version_major, tls_version_minor);
 
         return TLS_EVERSION;
@@ -111,7 +112,7 @@ parse_tls_header(const struct TLSProtocol *tls_data, const char *data, size_t da
         return TLS_EPROTOCOL;
     }
     if (data[pos] != TLS_HANDSHAKE_TYPE_CLIENT_HELLO) {
-        if (cfg.verbose) fprintf(stderr, "Not a client hello\n");
+        print_message(msg_probe_error, "Not a client hello\n");
 
         return TLS_EPROTOCOL;
     }
@@ -144,7 +145,7 @@ parse_tls_header(const struct TLSProtocol *tls_data, const char *data, size_t da
     pos += 1 + len;
 
     if (pos == data_len && tls_version_major == 3 && tls_version_minor == 0) {
-        if (cfg.verbose) fprintf(stderr, "Received SSL 3.0 handshake without extensions\n");
+        print_message(msg_probe_error, "Received SSL 3.0 handshake without extensions\n");
         return TLS_EVERSION;
     }
 
@@ -223,12 +224,12 @@ parse_server_name_extension(const struct TLSProtocol *tls_data, const char *data
         switch (data[pos]) { /* name type */
             case 0x00: /* host_name */
                 if(has_match(tls_data->sni_hostname_list, tls_data->sni_list_len, data + pos + 3, len)) {
-                    return len;
+                    return (int)len;
                 } else {
                     return TLS_ENOEXT;
                 }
             default:
-                if (cfg.verbose) fprintf(stderr, "Unknown server name extension name type: %d\n",
+                print_message(msg_probe_error, "Unknown server name extension name type: %d\n",
                       data[pos]);
         }
         pos += 3 + len;
@@ -252,9 +253,9 @@ parse_alpn_extension(const struct TLSProtocol *tls_data, const char *data, size_
             return TLS_EPROTOCOL;
 
         if (len > 0 && has_match(tls_data->alpn_protocol_list, tls_data->alpn_list_len, data + pos + 1, len)) {
-            return len;
+            return (int)len;
         } else if (len > 0) {
-            if (cfg.verbose) fprintf(stderr, "Unknown ALPN name: %.*s\n", (int)len, data + pos + 1);
+            print_message(msg_probe_error, "Unknown ALPN name: %.*s\n", (int)len, data + pos + 1);
         }
         pos += 1 + len;
     }
@@ -276,7 +277,7 @@ has_match(const char** list, size_t list_len, const char* name, size_t name_len)
 
     for (i = 0; i < list_len; i++) {
         item = &list[i];
-        if (cfg.verbose) fprintf(stderr, "matching [%.*s] with [%s]\n", (int)name_len, name, *item);
+        print_message(msg_probe_error, "matching [%.*s] with [%s]\n", (int)name_len, name, *item);
         if(!fnmatch(*item, name_nullterminated, 0)) {
             free(name_nullterminated);
             return 1;
@@ -300,11 +301,11 @@ struct TLSProtocol *
 tls_data_set_list(struct TLSProtocol *tls_data, int alpn, const char** list, size_t list_len) {
     if (alpn) {
         tls_data->alpn_protocol_list = list;
-        tls_data->alpn_list_len = list_len;
+        tls_data->alpn_list_len = (int)list_len;
         tls_data->match_mode.tls_match_alpn = 1;
     } else {
         tls_data->sni_hostname_list = list;
-        tls_data->sni_list_len = list_len;
+        tls_data->sni_list_len = (int)list_len;
         tls_data->match_mode.tls_match_sni = 1;
     }