hashtest: fix build so the suite actually runs

htest.c was missing the "typedef struct hash hash" that hash.h
requires, and the Makefile linked the top-level ../hash.o which is
built without -DHASH_DEBUG, leaving hash_dump/hash_item_print
undefined. Build a local hash.o with the flag instead. All 16 tests
now compile and pass.

ChangeLog

@@ -1,4 +1,45 @@
 vNEXT:
+	Silently ignore EAGAIN/EWOULDBLOCK to avoid
+	spurrious error logs upon UDP port scans.
+
+	verbose_packet now also dumps UDP packets.
+
+	print_message() restores errno, fix sslh-fork
+	exiting upong log errors.
+
+	Add incoming connection timeout management, which
+	was strangely missing.
+
+v2.3.1:
+	Fix segmentation fault in sslh-fork.
+
+	Add file access when using Landlock and Libwrap
+	together.
+
+	Mixed IPv4/IPv6 proxyprotocol setups will move both
+	addresses to IPv6 format on the server side.
+
+	Add CAP_NET_RAW to systemd config so transparent
+	proxying can work. Removed sslh-select systemd file:
+	don't repeat the same configuration file!
+
+	Changed SNI matching log messages from
+	`msg_probe_error` to `msg_probe_info`: beware if you
+	happen to use them...
+
+	Close unused file descriptors upon forking a worker
+	for a connection (in sslh-ev and sslh-select). In
+	particular, this prevents forked processes to
+	inherit the listen sockets and block a new main
+	process from starting.
+
+	More configuration sanity checks (e.g. using regex
+	or proxyprotocol options if libraries are not compiled in)
+
+	-V now outputs compile-time options so it is
+	possible to know what is compiled in.
+
+v2.3.0:
 	Added `max_connections` setting to `listen` and
 	`protocol` configuration; see the
 	[guide](doc/max_connections.md) for more
@@ -6,7 +47,8 @@ vNEXT:
 
 	accept() is now disabled for some time when ulimit -n is reached.
 
-	Support proxyprotocol on incoming connections.
+	Support proxyprotocol on incoming connections. See
+	the [guide](doc/proxyprotocol.md) for information.
 
 	Fix proxyprotocol target field (Thanks to Github user 404-Not-Found)
 

Dockerfile

@@ -3,8 +3,7 @@ ARG TARGET_ARCH="library"
 
 FROM docker.io/${TARGET_ARCH}/alpine:${ALPINE_VERSION} AS build
 
-WORKDIR /sslh
-
+# Install build dependencies for sslh and libproxyprotocol
 RUN apk add --no-cache \
         'gcc' \
         'libconfig-dev' \
@@ -12,15 +11,39 @@ RUN apk add --no-cache \
         'musl-dev' \
         'pcre2-dev' \
         'perl' \
+        'git' \
+        'autoconf' \
+        'automake' \
+        'libtool' \
         ;
 
+# Build libproxyprotocol
+WORKDIR /tmp
+RUN git clone https://github.com/kosmas-valianos/libproxyprotocol.git && \
+    cd libproxyprotocol && \
+    make && \
+    mkdir -p /usr/local/include/ && \
+    mv libs/libproxyprotocol.so /usr/local/lib/ && \
+    mv src/* /usr/local/include/
+
+# Set environment variables for sslh to find libproxyprotocol
+ENV C_INCLUDE_PATH=/usr/local/include
+ENV LIBRARY_PATH=/usr/local/lib
+ENV LD_LIBRARY_PATH=/usr/local/lib
+
+WORKDIR /sslh
 COPY . /sslh
 
+# Configure and build sslh
+# The configure script should automatically detect libproxyprotocol
 RUN ./configure && make sslh-select && strip sslh-select
 
 FROM docker.io/${TARGET_ARCH}/alpine:${ALPINE_VERSION}
 
+# Copy libproxyprotocol.so from the build stage
+COPY --from=build /usr/local/lib/libproxyprotocol.so* /usr/local/lib/
 COPY --from=build "/sslh/sslh-select" "/usr/local/bin/sslh"
+
 RUN apk add --no-cache \
         'libconfig' \
         'pcre2' \
@@ -35,4 +58,4 @@ COPY "./container-entrypoint.sh" "/init"
 ENTRYPOINT [ "/init" ]
 
 # required for updating iptables
-USER root:root
+USER root:root

Makefile.in

@@ -22,11 +22,11 @@ MAN=sslh.8.gz	# man page name
 # itself
 
 ifneq ($(strip $(ENABLE_SANITIZER)),)
-    CFLAGS_SAN=-fsanitize=address -fsanitize=leak -fsanitize=undefined -fsanitize=alignment
+    CFLAGS_SAN=-DENABLE_SANITIZER -fsanitize=address -fsanitize=leak -fsanitize=undefined -fsanitize=alignment
 endif
 
 ifneq ($(strip $(COV_TEST)),)
-    CFLAGS_COV=-fprofile-arcs -ftest-coverage
+    CFLAGS_COV=-DCOV_TEST -fprofile-arcs -ftest-coverage
 endif
 
 CC ?= gcc

README.md

@@ -5,7 +5,7 @@ sslh -- A ssl/ssh multiplexer
 them further based on tests performed on the first data
 packet sent by the remote client.
 
-Probes for HTTP, TLS/SSL (including SNI and ALPN), SSH,
+Probes for HTTP, TLS/SSL (including SNI and ALPN), SSH, WireGuard,
 OpenVPN, tinc, XMPP, SOCKS5, are implemented, and any other
 protocol that can be tested using a regular expression, can
 be recognised. A typical use case is to allow serving
@@ -112,8 +112,6 @@ docker run \
 docker-compose example
 
 ```yaml
-version: "3"
-
 services:
   sslh:
     image: ghcr.io/yrutschle/sslh:latest
@@ -136,8 +134,6 @@ 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
@@ -178,8 +174,6 @@ services:
 Transparent mode 2: using host networking
 
 ```yaml
-version: "3"
-
 services:
   sslh:
     build: https://github.com/yrutschle/sslh.git

TODO

@@ -8,7 +8,7 @@ shouldn't be construed to mean that any of this will happen.
 - have certain services available only from specified subnets
 
 - some sort of "service knocking" allowing to activate a
-  service upon some external even, similar to port knocking;
+  service upon some external event, similar to port knocking;
 for example, go to a specific URL to enable sslh forwarding
 to sshd for a set period of time:
     * sslh listens on 443 and only directs to httpd

collection.c

@@ -28,6 +28,7 @@
 /* Info to keep track of all connections */
 struct cnx_collection {
     gap_array* fd2cnx;  /* Array indexed by file descriptor to things in cnx[] */
+    int max_fd;
 };
 
 /* Allocates and initialises a new collection of connections with at least
@@ -42,6 +43,7 @@ cnx_collection* collection_init(int len)
     memset(collection, 0, sizeof(*collection));
 
     collection->fd2cnx = gap_init(len);
+    collection->max_fd = 0;
 
     return collection;
 }
@@ -54,10 +56,17 @@ void collection_destroy(cnx_collection* collection)
     free(collection);
 }
 
+int collection_max_fd(cnx_collection* collection)
+{
+    return collection->max_fd;
+}
+
 /* Points the file descriptor to the specified connection index */
 int collection_add_fd(cnx_collection* collection, struct connection* cnx, int fd)
 {
     gap_set(collection->fd2cnx, fd, cnx);
+    if (fd > collection->max_fd)
+        collection->max_fd = fd;
     return 0;
 }
 
@@ -74,8 +83,7 @@ struct connection* collection_alloc_cnx_from_fd(struct cnx_collection* collectio
     cnx->state = ST_PROBING;
     cnx->probe_timeout = time(NULL) + cfg.timeout;
 
-    gap_set(collection->fd2cnx, fd, cnx);
-
+    collection_add_fd(collection, cnx, fd);
     return cnx;
 }
 

collection.h

@@ -9,6 +9,7 @@ void collection_destroy(cnx_collection* collection);
 
 struct connection* collection_alloc_cnx_from_fd(cnx_collection* collection, int fd);
 int collection_add_fd(cnx_collection* collection, struct connection* cnx, int fd);
+int collection_max_fd(cnx_collection* collection);
 
 /* Remove a connection from the collection */
 int collection_remove_cnx(cnx_collection* collection, struct connection *cnx);

common.c

@@ -25,12 +25,6 @@
 #include <sys/prctl.h>
 #endif
 
-/* Added to make the code compilable under CYGWIN
- * */
-#ifndef SA_NOCLDWAIT
-#define SA_NOCLDWAIT 0
-#endif
-
 /* Make use of systemd socket activation
  * */
 #ifdef SYSTEMD
@@ -80,6 +74,13 @@ int get_fd_sockets(struct listen_endpoint *sockfd[])
     int sd = 0;
 
 #ifdef SYSTEMD
+    /* Sockets passed by systemd socket activation do not correspond to a
+     * `listen` entry in the configuration, but code dereferences
+     * endpoint->endpoint_cfg unconditionally (e.g. inc_listen_connections()
+     * and probe_client_protocol()), so give them a default, empty
+     * configuration: no max_connections, no proxyprotocol. */
+    static struct sslhcfg_listen_item default_endpoint_cfg;
+
     sd = sd_listen_fds(0);
     if (sd < 0) {
       print_message(msg_system_error, "sd_listen_fds(): %s\n", strerror(-sd));
@@ -92,6 +93,7 @@ int get_fd_sockets(struct listen_endpoint *sockfd[])
       for (i = 0; i < sd; i++) {
         (*sockfd)[i].socketfd = SD_LISTEN_FDS_START + i;
         (*sockfd)[i].type = SOCK_STREAM;
+        (*sockfd)[i].endpoint_cfg = &default_endpoint_cfg;
       }
     }
 #endif
@@ -209,6 +211,8 @@ static int start_listen_inet(struct listen_endpoint *sockfd[], int num_addr, str
 /* Same, but for UNIX sockets */
 static int start_listen_unix(struct listen_endpoint *sockfd[], int num_addr, struct sslhcfg_listen_item* cfg)
 {
+    struct sockaddr_un sun;
+
     int fd = socket(AF_UNIX, cfg->is_udp ? SOCK_DGRAM : SOCK_STREAM, 0);
     CHECK_RES_DIE(fd, "socket(AF_UNIX)");
 
@@ -218,10 +222,10 @@ static int start_listen_unix(struct listen_endpoint *sockfd[], int num_addr, str
         exit(4);
     }
 
-    struct sockaddr_un sun;
+    memset(&sun, 0, sizeof(sun));
     sun.sun_family = AF_UNIX;
     strncpy(sun.sun_path, cfg->host, sizeof(sun.sun_path)-1);
-    printf("binding [%s]\n", sun.sun_path);
+    print_message(msg_config, "binding [%s]\n", sun.sun_path);
     res = bind(fd, (struct sockaddr*)&sun, sizeof(sun));
     CHECK_RES_DIE(res, "bind(AF_UNIX)");
 
@@ -232,7 +236,7 @@ static int start_listen_unix(struct listen_endpoint *sockfd[], int num_addr, str
     memset(&(*sockfd)[num_addr-1], 0, sizeof((*sockfd)[num_addr-1]));
     (*sockfd)[num_addr-1].socketfd = fd;
     (*sockfd)[num_addr-1].type = cfg->is_udp ? SOCK_DGRAM : SOCK_STREAM;
-    (*sockfd)[num_addr-1].family = AF_INET;
+    (*sockfd)[num_addr-1].family = AF_UNIX;
     (*sockfd)[num_addr-1].endpoint_cfg = cfg;
 
     return num_addr;
@@ -428,9 +432,9 @@ static int connect_inet(struct connection *cnx, int fd_from, connect_blocking bl
                            cnx->proto->port);
     }
     for (a = cnx->proto->saddr; a; a = a->ai_next) {
-        /* When transparent or using proxyprotocol, make sure both 
-         * connections use the same address family (e.g. IP4 on both sides) */
-        if ((transparent || cnx->proto->proxyprotocol_is_present) && (a->ai_family != from.ai_addr->sa_family))
+        /* When transparent, make sure both connections use
+         * the same address family (e.g. IP4 on both sides) */
+        if (transparent && (a->ai_family != from.ai_addr->sa_family))
             continue;
         print_message(msg_connections_try, "trying to connect to %s family %d len %d\n",
                     sprintaddr(buf, sizeof(buf), a),
@@ -481,10 +485,13 @@ static int connect_unix(struct connection *cnx, int fd_from, connect_blocking bl
     struct sockaddr_storage ss;
     struct sockaddr_un* sun = (struct sockaddr_un*)&ss;
 
-    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    memset(&ss, 0, sizeof(ss));
     sun->sun_family = AF_UNIX;
     strncpy(sun->sun_path, cnx->proto->host, sizeof(sun->sun_path)-1);
 
+    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    CHECK_RES_RETURN(fd, "socket", -1);
+
     int res = connect(fd, (struct sockaddr*)sun, sizeof(*sun));
     CHECK_RES_RETURN(res, "connect", res);
 
@@ -905,7 +912,7 @@ int check_access_rights(int in_socket, const char* service)
     }
 
     if (!hosts_ctl((char*)service, host, addr_str, STRING_UNKNOWN)) {
-        print_message(msg_connections, "connection from %s(%s): access denied", host, addr_str);
+        print_message(msg_connections, "connection from %s(%s): access denied\n", host, addr_str);
         close(in_socket);
         return -1;
     }

common.h

@@ -9,6 +9,13 @@
 #define FD_SETSIZE 4096
 #endif
 
+/* Cygwin does not define some symbols
+ * */
+#ifndef SA_NOCLDWAIT
+#define SA_NOCLDWAIT 0
+#endif
+
+
 #define _GNU_SOURCE
 #include <sys/types.h>
 #include <fcntl.h>
@@ -193,11 +200,11 @@ extern struct addrinfo *addr_listen;
 extern const char* server_type;
 
 #if defined(__APPLE__) && (MAC_OS_X_VERSION_MIN_REQUIRED < 1080)
-extern int hosts_ctl();
+extern int hosts_ctl(char*, char*, char*, char*);
 #endif
 
 /* sslh-fork.c */
-void start_shoveler(int);
+void main_inetd(void);
 
 void main_loop(struct listen_endpoint *listen_sockets, int num_addr_listen);
 

configure.ac

@@ -7,12 +7,17 @@ AC_INIT
 AC_CONFIG_HEADERS(config.h)
 AC_CONFIG_FILES([Makefile])
 
-AC_CHECK_LIB([wrap], [hosts_ctl], [AC_DEFINE(HAVE_LIBWRAP) LIBS="$LIBS -lwrap" ], [])
-AC_CHECK_LIB([cap], [cap_get_proc], [AC_DEFINE(HAVE_LIBCAP) LIBS="$LIBS -lcap" ], [])
-AC_CHECK_LIB([bsd], [setproctitle], [AC_DEFINE(HAVE_LIBBSD) LIBS="$LIBS -lbsd" ], [])
+AC_CHECK_LIB([wrap], [hosts_ctl],
+  [AC_DEFINE([HAVE_LIBWRAP], [1], [Libwrap, to support host_ctl, /etc/allow and /etc/deny]) LIBS="$LIBS -lwrap"])
+AC_CHECK_LIB([cap], [cap_get_proc],
+  [AC_DEFINE([HAVE_LIBCAP], [1], [libcap support, to use Linux capabilities]) LIBS="$LIBS -lcap"])
+AC_CHECK_LIB([bsd], [setproctitle],
+  [AC_DEFINE([HAVE_LIBBSD], [1], [libbsd, to change process name]) LIBS="$LIBS -lbsd"])
 
-AC_CHECK_HEADERS(linux/landlock.h, AC_DEFINE(HAVE_LANDLOCK), [])
-AC_CHECK_HEADERS(proxy_protocol.h, [AC_DEFINE(HAVE_PROXYPROTOCOL) LIBS="$LIBS -lproxyprotocol" ], [])
+AC_CHECK_HEADERS(linux/landlock.h,
+  AC_DEFINE([HAVE_LANDLOCK], [1], [Landlock sandboxing Linux LSM]))
+AC_CHECK_HEADERS(proxy_protocol.h,
+  [AC_DEFINE([HAVE_PROXYPROTOCOL], [1], [Support for Proxy-protocol using libproxyprotocol]) LIBS="$LIBS -lproxyprotocol"])
 
 LIBS="$LIBS"
 AC_SUBST([LIBS])

doc/podman.md

@@ -33,6 +33,8 @@ olegstepura](https://github.com/yrutschle/sslh/issues/448)
       # ... (make sure to mount config as you like)
     command: --transparent -F/etc/sslh/sslh.cfg # parameter --transparent here is needed to trigger configure_iptables in init script
    state: started
+   # ⚠️ Important: Never add a `network:` here, otherwise this setup will NOT work.
+   # Adding a network disconnects the sslh container from the pod's shared localhost.
 
 - name: "Create the caddy container"
   containers.podman.podman_container:
@@ -95,26 +97,60 @@ protocols:
 );
 ```
 
-I omitted caddy configs here as it's not important. Some unrelated container configs were also dropped.
-In the example above `sslh`, `caddy` and `ssh-proxy` are 3 containers in the same pod, all listening on `localhost`. SSLH has to listen on `444` because caddy already listens on `443` and it's more complex to reconfigure caddy port because of let's encrypt (caddy itself "thinks" it is bound to your host interface).
+I omitted Caddy configs here since they're irrelevant, and some unrelated container configs were also dropped for clarity.
 
-Scheme of port mapping is (all containers share same `localhost`):
+In the example above, `sslh`, `caddy`, and `ssh-proxy` are **three containers inside the same Podman pod**, all sharing the same **pod-local `localhost`**.  
+
+`sslh` listens on port **444** instead of **443**, because `caddy` already binds to port `443`, and reconfiguring Caddy is more complex due to its Let's Encrypt integration (Caddy itself "thinks" it’s bound to your host interface).  
+
+#### Port mapping scheme  
+All containers **share the same `localhost`** inside the pod:  
 ```
 host 443 → pod 444 (sslh) → pod 443 (caddy)
 ```
-- podman connects host `443` port to pod's `444` port
-- `sslh` listens `444` on `localhost`, reroutes tls to `caddy` on `localhost:443`
-- `caddy` listens `443` on `localhost` (reverse-proxies to other apps on private network)
-Reverse-proxied services get correct IP in `X-Forwarded-For` header.
 
-Takeaways:
-- `net.ipv4.conf.default.route_localnet` is setup only in container, not on host, which is nice.
-- same with iptables and route rules applied by `init` script in sslh container
-- `sslh` proxy to other services in the private network will not work (because transparent mode is enabled) even if that other service does not need real IP
-	- with transparent mode all services that `sslh` will connect to should be attached to this pod making it listen on `localhost` of the pod
-	- ports of containers should not clash
-	- ports should be published on pod level, not on containers
-	- containers should not be configured to connect to custom networks
-- because of the above proxying ssh to host will also not work out of the box, `sslh` should connect to `localhost` and not to a random IP. While adding another proxy as a container to the same pod sounds like an overkill I don't see any other solution, so `socat` is used as an additional proxy.
-- `reverse_proxy` by caddy to other containers in the same custom network (as pod is attached to) works (e.g. caddy can connect to other IPs from custom network). `socat` can also connect to host and/or other containers in custom network.
 
+- **Podman** maps the host’s `443` → pod’s `444`.  
+- **SSHL** listens on `localhost:444` inside the pod and forwards TLS traffic to `caddy` on `localhost:443`.  
+- **Caddy** listens on `localhost:443` and reverse-proxies to other services in the private network.  
+
+This ensures that **reverse-proxied services** receive the correct client IP in the `X-Forwarded-For` header.
+
+---
+
+### Important note  
+
+⚠️ Do **not** set a `network:` parameter for the `sslh` container when it belongs to a Podman pod.  
+Setting a custom network **forces Podman to detach the container from the pod’s shared network namespace** and creates a **separate `localhost`** for that container, breaking transparent routing.
+
+For example:  
+
+```yaml
+command: --transparent -F/etc/sslh/sslh.cfg # parameter --transparent here is needed to trigger configure_iptables in init script
+state: started
+# ⚠️ Never add a `network:` here!
+# Adding a network disconnects the sslh container from the pod's shared localhost,
+# causing transparent routing to fail.
+```
+
+### Key takeaways  
+
+- `net.ipv4.conf.default.route_localnet` and iptables rules are applied **inside the `sslh` container only**, not on the host.  
+- The `sslh` **init** script manages all required `iptables` and routing rules inside of the container.  
+- **Transparent mode restrictions**:
+    - Any service `sslh` proxies traffic to **must** be inside the same pod and bound to its **pod-local `localhost`**.
+    - Container ports must not conflict within the pod.
+    - Ports should be published **at the pod level**, **not per-container**.
+    - Containers inside this pod **must not** be attached to any custom networks.
+- Because of transparent routing, `sslh` cannot directly proxy SSH to the host IP.  
+  A workaround is to run a lightweight **socat** container in the same pod:  
+  `TCP-LISTEN:222 → TCP:host.containers.internal:22`
+- Caddy’s `reverse_proxy` **to other containers** in the **custom network attached to the pod** still works properly.
+- `socat` can also connect to both the **host** and **other containers** inside the custom network without issues.
+
+### Tested setup
+
+- Confirmed working on **Debian Trixie**  
+- Using **Podman 5.4.2**  
+- Pinned `podman` and related dependencies (`conmon`, `slirp4netns`, `aardvark-dns`, etc.) from **Debian testing**,  
+  since **stable** often ships outdated versions that can break this setup.

doc/proxyprotocol.md

@@ -27,7 +27,6 @@ protocols:
 (
      { name: "ssh";  host: "localhost"; port: "2222"; },
      { name: "tls";  host: "localhost"; port: "8080"; proxyprotocol: 2; }
-     );
 );
 ```
 
@@ -77,7 +76,6 @@ protocols:
 (
      { name: "ssh";  host: "localhost"; port: "2222"; proxyprotocol: 0; },
      { name: "tls";  host: "localhost"; port: "8080"; }
-     );
 );
 ```
 

echosrv-conf.c

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Fri Aug 29 20:43:29 2025. 
+ * on Wed Sep 10 15:49:49 2025. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2024  Yves Rutschle

echosrv-conf.h

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Fri Aug 29 20:43:29 2025. 
+ * on Wed Sep 10 15:49:49 2025. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2024  Yves Rutschle

echosrv.c

@@ -68,9 +68,13 @@ void start_echo(int fd)
     int first = 1;
 
     prefix_len = strlen(cfg.prefix);
+    if (prefix_len >= sizeof(buffer)) {
+        fprintf(stderr, "prefix too long\n");
+        return;
+    }
 
     memset(buffer, 0, sizeof(buffer));
-    strcpy(buffer, cfg.prefix);
+    memcpy(buffer, cfg.prefix, prefix_len);
 
     while (1) {
         ret = read(fd, buffer + prefix_len, sizeof(buffer) - prefix_len);
@@ -147,19 +151,24 @@ void udp_echo(struct listen_endpoint* listen_socket)
     memset(data, 0, sizeof(data));
 
     size_t prefix_len = strlen(cfg.prefix);
+    if (prefix_len >= sizeof(data) - 1) {
+        fprintf(stderr, "prefix too long\n");
+        return;
+    }
     memcpy(data, cfg.prefix, prefix_len);
 
     while (1) {
         addrlen = sizeof(src_addr);
         ssize_t len = recvfrom(listen_socket->socketfd,
                            data + prefix_len,
-                           sizeof(data) - prefix_len,
+                           sizeof(data) - prefix_len - 1,
                            0,
                            &src_addr,
                            &addrlen);
 
         if (len < 0) {
             perror("recvfrom");
+            continue;
         }
         *(data + prefix_len + len) = 0;
         fprintf(stderr, "%zd %s\n", len, data + prefix_len);

echoѕrv-conf.h

@@ -1,109 +0,0 @@
-/* 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

@@ -55,6 +55,9 @@ syslog_facility: "auth";
 # is_unix: listen in the UNIX socket domain (default is TCP)
 # keepalive: set TCP_KEEPALIVE
 # max_connections: drop incoming connections after this count
+# proxyprotocol: [true|false]: this endpoint expects
+#   proxyprotocol headers on incoming connections. Refer to
+#   doc/proxyprotocol.md
 listen:
 (
     { host: "thelonious"; port: "443"; max_connections: 5; },
@@ -156,6 +159,9 @@ protocols:
 # 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" ]; },
+# More recent versions of QUIC migth work with this:
+     { name: "regex"; host: "localhost"; is_udp: true; port: "4443"; regex_patterns: [ "^[\x40-\x7F\xC0-\xFF]" ]; },
+# See https://github.com/yrutschle/sslh/issues/466 for discussions on QUIC
 
 # Regex examples -- better use the built-in probes for real-world use!
 # OpenVPN

hash.c

@@ -155,6 +155,10 @@ static int distance(int current_index, hash* h, hash_item item)
         return current_index - wanted_index + h->hash_size;
 }
 
+int hash_insertable(hash* h)
+{
+    return (h->item_cnt < h->hash_size);
+}
 
 int hash_insert(hash* h, hash_item new)
 {

hash.h

@@ -13,6 +13,7 @@ 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_insertable(hash* h); /* Is it possible to insert: any space left? */
 int hash_insert(hash* h, hash_item new);
 int hash_remove(hash* h, hash_item item);
 

hashtest/Makefile

@@ -1,6 +1,9 @@
 
 CFLAGS=-DHASH_DEBUG -O2 -Wall
-OBJ=../hash.o ../gap.o htest.o
+OBJ=hash.o ../gap.o htest.o
+
+hash.o: ../hash.c
+	$(CC) $(CFLAGS) -c -o $@ $<
 
 htest: $(OBJ)
 	$(CC) -o htest $(OBJ)

hashtest/htest.c

@@ -29,6 +29,7 @@ struct hash_item {
 };
 
 typedef struct hash_item* hash_item;
+typedef struct hash hash;
 
 #include "../hash.h"
 

landlock.c

@@ -118,7 +118,7 @@ static int add_resolv(int ruleset_fd)
 static int add_libwrap(int ruleset_fd)
 {
     /* Files for libwrap */
-#ifdef LIBWRAP
+#ifdef HAVE_LIBWRAP
     add_path_ro(ruleset_fd, LL_FILE, "/etc/hosts.allow");
     add_path_ro(ruleset_fd, LL_FILE, "/etc/hosts.deny");
 #endif

log.c

@@ -48,7 +48,7 @@ msg_info msg_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
+    &cfg.verbose_int_error
 };
 
 /* System errors: when the system around us fails us: memory allocation, fork, ... */
@@ -107,6 +107,12 @@ void print_message(msg_info info, const char* str, ...)
 {
     va_list ap;
 
+    /* print_message() being used for logging, it is often used after system
+     * calls and before caller checks errno; as it itself does not do anything
+     * with errno (can't log an error if error logging fails), it just restores
+     * it on exit */
+    int saved_errno = errno;
+
     if ((*info.verbose & MSG_STDOUT) && ! cfg.inetd) {
         va_start(ap, str);
         vfprintf(stderr, str, ap);
@@ -125,6 +131,8 @@ void print_message(msg_info info, const char* str, ...)
         fflush(logfile_fp);
         va_end(ap);
     }
+
+    errno = saved_errno;
 }
 
 static int do_syslog = 1; /* Should we syslog? controled by syslog_facility = "none" */

probe.c

@@ -88,20 +88,20 @@ struct sslhcfg_protocols_item* timeout_protocol(void)
 void hexdump(msg_info msg_info, const char *mem, unsigned int len)
 {
     unsigned int i, j;
-    char str[10 + HEXDUMP_COLS * 4 + 2];
+    char str[12 + HEXDUMP_COLS * 4 + 2]; /* offset <= 12, hex+ascii 64, '\n'+'\0' */
     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)
-            c += sprintf(&str[c], "0x%06x: ", i);
+            c += snprintf(&str[c], sizeof(str) - c, "0x%06x: ", i);
 
         /* print hex data */
         if(i < len)
-            c += sprintf(&str[c], "%02x ", 0xFF & mem[i]);
+            c += snprintf(&str[c], sizeof(str) - c, "%02x ", 0xFF & mem[i]);
         else /* end of block, just aligning for ASCII dump */
-            c+= sprintf(&str[c], "   ");
+            c += snprintf(&str[c], sizeof(str) - c, "   ");
 
         /* print ASCII dump */
         if(i % HEXDUMP_COLS == (HEXDUMP_COLS - 1)) {
@@ -156,14 +156,15 @@ static int is_openvpn_protocol (const char*p,ssize_t len, struct sslhcfg_protoco
         if (len < 2)
             return PROBE_AGAIN;
 
-        packet_len = ntohs(*(uint16_t*)p);
+        /* p may be unaligned (e.g. on ARM), do not cast to uint16_t* */
+        uint16_t wire_len;
+        memcpy(&wire_len, p, sizeof(wire_len));
+        packet_len = ntohs(wire_len);
         return packet_len == len - 2;
     } else {
         if (len < 1)
             return PROBE_NEXT;
 
-        printf("opcode: %d\n", (p[0] & OVPN_OPCODE_MASK) >> 3);
-
         if ((p[0] & OVPN_OPCODE_MASK) != OVPN_CONTROL_HARD_RESET_CLIENT_V1 &&
             (p[0] & OVPN_OPCODE_MASK) != OVPN_CONTROL_HARD_RESET_CLIENT_V2 &&
             (p[0] & OVPN_OPCODE_MASK) != OVPN_CONTROL_HARD_RESET_CLIENT_V3
@@ -207,7 +208,9 @@ static int is_wireguard_protocol(const char *p, ssize_t len, struct sslhcfg_prot
         return PROBE_NEXT;
 
     // Handshake Init: p[0] = 0x01, p[1..3] = 0x000000 (reserved)
-    if (ntohl(*(uint32_t*)p) != 0x01000000)
+    uint32_t type;
+    memcpy(&type, p, sizeof(type));
+    if (ntohl(type) != 0x01000000)
         return PROBE_NEXT;
 
     return PROBE_MATCH;
@@ -409,20 +412,25 @@ static int is_teamspeak_protocol(const char *p, ssize_t len, struct sslhcfg_prot
     if (len < 8)
         return PROBE_NEXT;
 
-    return !strncmp(p, "TS3INIT1", len);
+    /* Compare a fixed-length prefix: strncmp(p, "TS3INIT1", len) would read
+     * len bytes of the 9-byte literal and never match a real packet, whose
+     * byte 8 is not NUL */
+    return !memcmp(p, "TS3INIT1", 8);
 }
 
 static int is_msrdp_protocol(const char *p, ssize_t len, struct sslhcfg_protocols_item* proto)
 {
     char version;
-    char packet_len;
+    uint16_t 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;
+    memcpy(&packet_len, p+2, sizeof(packet_len));
+    /* The declared TPKT length must fit the entire received packet; a char
+     * would truncate e.g. 0x0107 to 7 and accept truncated packets */
+    return ntohs(packet_len) == len;
 }
 
 #ifdef ENABLE_REGEX
@@ -467,6 +475,9 @@ int probe_buffer(char* buf, int len,
     struct sslhcfg_protocols_item* p;
     int i, res, again = 0;
 
+    print_message(msg_packets, "hexdump of incoming packet:\n");
+    hexdump(msg_packets, buf, len);
+
     *proto_out = NULL;
     for (i = 0; i < proto_len; i++) {
         char* probe_str[3] = {"PROBE_NEXT", "PROBE_MATCH", "PROBE_AGAIN"};

processes.c

@@ -46,9 +46,9 @@ int tidy_connection(struct connection *cnx, struct loop_info* fd_info)
             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->q[i].begin_deferred_data)
+            free(cnx->q[i].begin_deferred_data);
     }
 
     if (cnx->type == SOCK_DGRAM)
@@ -142,6 +142,10 @@ static int pid_cmp(hash_item item1, hash_item item2)
 void decrease_forked_connection(struct loop_info* loop, pid_t pid) {
     struct pid2proto p2p = { .pid = pid };
     struct pid2proto* found = hash_find(loop->pid2proto, &p2p);
+    if (!found) {
+        print_message(msg_int_error, "SIGCHLD for unknown pid %d\n", pid);
+        return;
+    }
     dec_proto_connections(found->proto);
     dec_listen_connections(found->endpoint);
 
@@ -152,6 +156,13 @@ void decrease_forked_connection(struct loop_info* loop, pid_t pid) {
 
 typedef struct pid2proto* hash_item;
 #include "hash.h"
+
+int has_space_to_fork(struct loop_info* fd_info)
+{
+    return hash_insertable(fd_info->pid2proto);
+}
+
+
 void remember_child_data(struct loop_info* fd_info,
                          struct connection* cnx, pid_t pid)
 {
@@ -160,7 +171,10 @@ void remember_child_data(struct loop_info* fd_info,
     pid2proto->proto = cnx->proto;
     pid2proto->endpoint = cnx->endpoint;
     if (hash_insert(fd_info->pid2proto, pid2proto)) {
-        /* TODO something if it fails */
+        print_message(msg_int_error, "hash_insert for pid %d failed\n", pid);
+        /* This should not happen as called is supposed to check that space is
+         * available in the hash */
+        exit(1);
     }
 }
 
@@ -168,8 +182,11 @@ static int max_forking_connections(void)
 {
     int max_cnx = 0;
     for (int i = 0; i < cfg.protocols_len; i++) {
-        if (cfg.protocols[i].fork)
-            max_cnx += cfg.protocols[i].max_connections;
+        if (cfg.protocols[i].fork) {
+            if (cfg.protocols[i].max_connections_is_present)
+                max_cnx += cfg.protocols[i].max_connections;
+            else max_cnx += 512; /* A magic number that's hopefully high enough */
+        }
     }
     return max_cnx;
 }
@@ -183,7 +200,7 @@ static int next_power_of_two(int n)
     return n + 1;
 }
 
-void loop_init(struct loop_info* loop, int num_addr_listen)
+void loop_init(struct loop_info* loop, struct listen_endpoint* listen_sockets, int num_addr_listen)
 {
     memset(loop, 0, sizeof(*loop));
     loop->collection = collection_init(0);
@@ -193,6 +210,7 @@ void loop_init(struct loop_info* loop, int num_addr_listen)
     udp_init(loop);
     tcp_init();
 
+    loop->listen_sockets = listen_sockets;
     loop->num_addr_listen = num_addr_listen;
 
     int max_forks = next_power_of_two(max_forking_connections());

processes.h

@@ -23,6 +23,8 @@ struct loop_info {
     hash* pid2proto; /* to follow which forked PID is processing what protocol for connection count */
 
     watchers* watchers;
+
+    struct listen_endpoint* listen_sockets;
     int num_addr_listen;  /* How many listen endpoints do we have here */
 
     cnx_collection* collection; /* Collection of connections linked to this loop */
@@ -32,11 +34,12 @@ 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);
-void loop_init(struct loop_info* loop, int num_addr_listen);
+void loop_init(struct loop_info* loop, struct listen_endpoint* listen_sockets, int num_addr_listen);
 
 void remember_child_data(struct loop_info* fd_info, 
                          struct connection* cnx, pid_t pid);
 void decrease_forked_connection(struct loop_info* loop, pid_t pid);
+int has_space_to_fork(struct loop_info* loop);
 
 /* These must be declared in the loop handler, sslh-ev or sslh-select */
 void watchers_add_read(watchers* w, int fd);
@@ -46,4 +49,6 @@ void watchers_del_write(watchers* w, int fd);
 
 void watcher_sigchld(struct loop_info* fd_info, struct connection* cnx, pid_t pid);
 
+void close_listen_endpoints(struct loop_info* loop);
+
 #endif

proxyprotocol.c

@@ -112,7 +112,7 @@ int pp_write_header(int pp_version, struct connection* cnx)
     if (res == -1) return -1;
     pp_info_in_v1.address_family = family_to_pp(addr.ai_addr->sa_family);
 
-    res = get_info(cnx->q[1].fd, SOCK,
+    res = get_info(cnx->q[0].fd, SOCK,
              &addr,
              &pp_info_in_v1.dst_addr,
              &pp_info_in_v1.dst_port
@@ -122,7 +122,7 @@ int pp_write_header(int pp_version, struct connection* cnx)
     uint8_t *pp1_hdr = pp_create_hdr(pp_version, &pp_info_in_v1, &pp1_hdr_len, &error);
 
     if (!pp1_hdr) {
-        print_message(msg_system_error, "pp_create_hrd:%d:%s\n", error, pp_strerror(error));
+        print_message(msg_system_error, "pp_create_hdr:%d:%s\n", error, pp_strerror(error));
         return -1;
     }
     defer_write_before(&cnx->q[1], pp1_hdr, pp1_hdr_len);

proxyprotocol.h

@@ -13,7 +13,7 @@ int pp_header_len(char* buffer, int len);
 #else /* HAVE_PROXYPROTOCOL */
 
 static inline int pp_write_header(int pp_version, struct connection* cnx) { return 0; }
-static int pp_log_connection(char* buffer, ssize_t buffer_len) { return 0; }
+static inline int pp_log_connection(char* buffer, ssize_t buffer_len) { return 0; }
 static inline int pp_header_len(char*, int) { return 0; }
 
 #endif /* HAVE_PROXYPROTOCOL */

scripts/systemd.sslh-select@.service

@@ -1,27 +0,0 @@
-[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

@@ -1,5 +1,5 @@
 [Unit]
-Description=SSL/SSH multiplexer (fork mode) for %I
+Description=SSL/SSH multiplexer for %I
 After=network.target
 
 [Service]
@@ -8,8 +8,8 @@ ExecStart=/usr/sbin/sslh -F/etc/sslh/%I.cfg -f $DAEMON_OPTS
 KillMode=process
 #Hardening
 PrivateTmp=true
-CapabilityBoundingSet=CAP_NET_BIND_SERVICE
-AmbientCapabilities=CAP_NET_BIND_SERVICE
+CapabilityBoundingSet=CAP_SETGIT CAP_SETUID CAP_NET_BIND_SERVICE CAP_NET_RAW
+AmbientCapabilities=CAP_NET_BIND_SERVICE CAP_NET_RAW
 SecureBits=noroot-locked
 ProtectSystem=strict
 ProtectHome=true

sslh-conf.c

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Fri Aug 29 20:43:29 2025. 
+ * on Wed Sep 10 15:49:49 2025. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2024  Yves Rutschle

sslh-conf.h

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Fri Aug 29 20:43:29 2025. 
+ * on Wed Sep 10 15:49:49 2025. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2024  Yves Rutschle

sslh-ev.c

@@ -26,6 +26,7 @@
 #include "log.h"
 #include "udp-listener.h"
 #include "tcp-listener.h"
+#include "sslh-conf.h"
 
 
 const char* server_type = "sslh-ev";
@@ -167,6 +168,41 @@ static void temporary_stop_accept_watchers(ev_io* io)
     ev_timer_start(EV_A_ timer);
 }
 
+
+/* Timer to timeout incoming connections that send no data.
+ * It's set to cnx.timeout during initialisation, then started when at least
+ * one connection is probing. It's stopped when the last probing connection is
+ * forwarded. Whenever it fires, it processes the first probing connection
+ * (which is due to time out), then resets the timer to trigger when the next
+ * connection is due. This relies on the loop->probing_list */
+static ev_timer probe_timer;
+
+static void probe_timeout_cb(EV_P_ ev_timer* timer, int revents)
+{
+    struct loop_info* info = ev_userdata(EV_A);
+
+    ev_timer_stop(EV_A_ &probe_timer);
+
+    /* Process all probing connections that have timed out */
+    if (info->num_probing > 0) {
+        struct connection* cnx = gap_get(info->probing_list, 0);
+        if (cnx) {  /* impossible cnx is NULL? */
+            probing_read_process(cnx, info);
+        }
+    }
+
+    /* If there is at least one left, restart the timer to fire depending on
+     * the next connection to time out */
+    if (info->num_probing > 0) {
+        struct connection* cnx = gap_get(info->probing_list, 0);
+        time_t duration = cnx->probe_timeout - time(NULL);
+        if (duration <= 0) duration = 1;
+        ev_timer_set(EV_A_ &probe_timer, duration, 0);
+        ev_timer_start(EV_A_ &probe_timer);
+    }
+}
+
+
 /* The accept() callback, called when there is READ activity.
  *
  * accept()ing when the process as reached its file descriptor limit (ulimit -n) is can of worms with no solution (see libev's manual "The special problem of accept()ing when you can't").
@@ -176,7 +212,14 @@ static void temporary_stop_accept_watchers(ev_io* io)
 static void cnx_accept_cb(EV_P_ ev_io *w, int revents)
 {
     struct loop_info* info = ev_userdata(EV_A);
-    if (!cnx_accept_process(info, gap_get(info->watchers->fd2ls, w->fd))) {
+    struct connection* cnx = cnx_accept_process(info, gap_get(info->watchers->fd2ls, w->fd));
+
+    if (cnx) {
+        if (info->num_probing == 1) {  /* This is the first connection, start the timer */
+            ev_timer_set(EV_A_ &probe_timer, cfg.timeout, 0);
+            ev_timer_start(EV_A_ &probe_timer);
+        }
+    } else {  /* accept() failed, probably all file descriptors are used */
         switch (errno) {
         case EMFILE:
         case ENFILE:  /* Not sure ENFILE should be included here */
@@ -207,13 +250,14 @@ void watcher_sigchld(struct loop_info* fd_info, struct connection* cnx, pid_t pi
     ev_child_start(EV_DEFAULT_ cw);
 }
 
-
 void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
 {
     struct loop_info ev_info;
     loop = EV_DEFAULT;
 
-    loop_init(&ev_info, num_addr_listen);
+    ev_timer_init(&probe_timer, &probe_timeout_cb, cfg.timeout, 0);
+
+    loop_init(&ev_info, listen_sockets, num_addr_listen);
 
     watchers_init(&ev_info.watchers, listen_sockets, num_addr_listen);
     ev_set_userdata(EV_A_ &ev_info);
@@ -221,7 +265,7 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
     ev_run(EV_A_ 0);
 }
 
-void start_shoveler(int listen_socket) {
+void main_inetd(void) {
     print_message(msg_config_error, "inetd mode is not supported in libev mode\n");
     exit(1);
 }

sslh-fork.c

@@ -69,7 +69,7 @@ int shovel(struct connection *cnx)
 
 /* Child process that finds out what to connect to and proxies 
  */
-void start_shoveler(int in_socket)
+static void start_shoveler(int in_socket, struct listen_endpoint* endpoint)
 {
    fd_set fds;
    struct timeval tv;
@@ -79,6 +79,7 @@ void start_shoveler(int in_socket)
 
    init_cnx(&cnx);
    cnx.q[0].fd = in_socket;
+   cnx.endpoint = endpoint;
 
    FD_ZERO(&fds);
    FD_SET(in_socket, &fds);
@@ -130,6 +131,22 @@ void start_shoveler(int in_socket)
    exit(0);
 }
 
+
+void main_inetd(void)
+{
+    struct listen_endpoint endpoint = {0};
+    struct sslhcfg_listen_item endpoint_cfg = {0};
+
+    /* Empty configuration: no connection limits, not proxyprotocol... */
+    endpoint.endpoint_cfg = &endpoint_cfg;
+
+    close(fileno(stderr)); /* Make sure no error will go to client */
+    tcp_init();
+    start_shoveler(0, &endpoint);
+    exit(0);
+}
+
+
 static pid_t *listener_pid;
 static int listener_pid_number = 0;
 
@@ -207,9 +224,10 @@ static void process_signals(struct listen_endpoint* endpoint)
 void tcp_listener(struct listen_endpoint* endpoint, int num_endpoints, int active_endpoint)
 {
     int i, in_socket;
+    struct listen_endpoint* self = &endpoint[active_endpoint];
 
     while (1) {
-        in_socket = accept(endpoint[active_endpoint].socketfd, 0, 0);
+        in_socket = accept(self->socketfd, 0, 0);
         if (in_socket == -1) {
             print_message(msg_system_error, "%s:%d:%s:%d:%s\n",
                           __FILE__, __LINE__, "accept", errno, strerror(errno));
@@ -226,33 +244,34 @@ void tcp_listener(struct listen_endpoint* endpoint, int num_endpoints, int activ
                 continue;
 
             case EINTR:
-                process_signals(endpoint);
+                process_signals(self);
                 continue;
 
             default:  /* Otherwise, it's something wrong in our parameters, we fail */
                 return;
             }
         }
-        endpoint->num_connections++;
-        print_message(msg_fd, "accepted fd %d (%d concurrent connections)\n", in_socket, endpoint->num_connections);
-        if ((endpoint->endpoint_cfg->max_connections_is_present) 
-            && (endpoint->num_connections > endpoint->endpoint_cfg->max_connections)) 
+        self->num_connections++;
+        print_message(msg_fd, "accepted fd %d (%d concurrent connections)\n", in_socket, self->num_connections);
+        if ((self->endpoint_cfg->max_connections_is_present)
+            && (self->num_connections > self->endpoint_cfg->max_connections))
         {
             print_message(msg_fd, "too many connection, reclosing fd %d\n", in_socket);
-            endpoint->num_connections--;
+            self->num_connections--;
             close(in_socket);
             continue;
         }
 
         switch(fork()) {
         case -1: print_message(msg_system_error, "fork failed: err %d: %s\n", errno, strerror(errno));
+                 self->num_connections--;  /* no child will reap it */
                  break;
 
         case 0: /* In child process */
                  /* Shoveler processes don't need to hog file descriptors */
                  for (i = 0; i < num_endpoints; i++)
                      close(endpoint[i].socketfd);
-                 start_shoveler(in_socket);
+                 start_shoveler(in_socket, self);
                  exit(0);
 
         default: /* In parent process */

sslh-main.c

@@ -30,6 +30,8 @@
 #include <pcre2.h>
 #endif
 
+#include <sys/un.h>
+
 #include "common.h"
 #include "probe.h"
 #include "log.h"
@@ -72,16 +74,16 @@ static void printsettings(void)
     for (i = 0; i < cfg.protocols_len; i++ ) {
         p = &cfg.protocols[i];
         if (p->is_unix) {
-            sprintf(buf, "unix socket: %s", p->host);
+            snprintf(buf, sizeof(buf), "unix socket: %s", p->host);
         } else {
             if (p->resolve_on_forward) {
                 strcpy(buf, "resolve on forward: ");
                 size_t len = strlen(buf);
-                sprintf(buf+len, "%s:%s", p->host, p->port);
+                snprintf(buf+len, sizeof(buf)-len, "%s:%s", p->host, p->port);
             } else {
                 sprintaddr(buf, sizeof(buf), p->saddr);
                 size_t len = strlen(buf);
-                sprintf(buf+len, " family %d %d",
+                snprintf(buf+len, sizeof(buf)-len, " family %d %d",
                         p->saddr->ai_family,
                         p->saddr->ai_addr->sa_family);
             }
@@ -220,6 +222,77 @@ static void config_protocols()
     }
 }
 
+static void config_sanity_regex(const struct sslhcfg_protocols_item* prot)
+{
+    if (prot->regex_patterns_len > 0) {
+        if (strcmp(prot->name, "regex") != 0) {
+            print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
+                          "regex_patterns setting is only applicable to `regex' probe. Ignoring setting.\n",
+                          prot->name, prot->host, prot->port);
+        }
+#ifndef ENABLE_REGEX
+        print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
+                      "Uses regex_patterns, but libpcre2 support was not compiled in. Ignoring setting.\n",
+                      prot->name, prot->host, prot->port);
+#endif
+    }
+}
+
+/* If user specified proxyprotocol but it is not compiled in, it should not be
+ * ignored as the resulting configuration will most likely not work. In that
+ * case, die. */
+static void config_sanity_proxyprotocol(const struct sslhcfg_protocols_item* prot)
+{
+#ifndef HAVE_PROXYPROTOCOL
+    if (prot->proxyprotocol_is_present) {
+        print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
+                      "Uses proxyprotocol, but libproxyprotocol support was not compiled in.\n",
+                      prot->name, prot->host, prot->port);
+        exit(1);
+    }
+#endif
+}
+
+static void config_sanity_listen_proxyprotocol(const struct sslhcfg_listen_item* endpoint)
+{
+#ifndef HAVE_PROXYPROTOCOL
+    if (endpoint->proxyprotocol) {
+        print_message(msg_config_error, "listen on host: \"%s\"; port: \"%s\": "
+                      "Uses proxyprotocol, but libproxyprotocol support was not compiled in.\n",
+                      endpoint->host, endpoint->port);
+        exit(1);
+    }
+#endif
+}
+
+
+/* If user specifies libwrap setting but it is not compiled in, it should
+ * result in a working configuration, but not what they expected, so warn */
+static void config_sanity_libwrap(const struct sslhcfg_protocols_item* prot)
+{
+#ifndef HAVE_LIBWRAP
+    if (prot->service_is_present) {
+        print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
+                      "WARNING: `service' specified but libwrap not compiled in. Ignoring setting.\n",
+                      prot->name, prot->host, prot->port);
+    }
+#endif
+}
+
+/* sun_path has a fixed, compile-time size (typically 108 chars): a configured
+ * unix socket path that does not fit can never work, so reject it once at
+ * startup rather than at bind()/connect() time */
+static void config_sanity_unix_path(const char* host)
+{
+    size_t path_max = sizeof(((struct sockaddr_un*)0)->sun_path);
+
+    if (host && strlen(host) >= path_max) {
+        print_message(msg_config_error,
+                      "unix socket path too long (%zd, max %zd): %s\n",
+                      strlen(host), path_max - 1, host);
+        exit(4);
+    }
+}
 
 void config_sanity_check(struct sslhcfg_item* cfg)
 {
@@ -233,6 +306,12 @@ void config_sanity_check(struct sslhcfg_item* cfg)
     }
 #endif
 
+    for (i = 0; i < cfg->listen_len; i++) {
+        config_sanity_listen_proxyprotocol(&cfg->listen[i]);
+        if (cfg->listen[i].is_unix)
+            config_sanity_unix_path(cfg->listen[i].host);
+    }
+
     for (i = 0; i < cfg->protocols_len; ++i) {
         if (strcmp(cfg->protocols[i].name, "tls") != 0) {
             if (cfg->protocols[i].sni_hostnames_len) {
@@ -249,6 +328,12 @@ void config_sanity_check(struct sslhcfg_item* cfg)
             }
         }
 
+        config_sanity_regex(&cfg->protocols[i]);
+        config_sanity_proxyprotocol(&cfg->protocols[i]);
+        config_sanity_libwrap(&cfg->protocols[i]);
+        if (cfg->protocols[i].is_unix)
+            config_sanity_unix_path(cfg->protocols[i].host);
+
         if (cfg->protocols[i].is_udp) {
             if (cfg->protocols[i].tfo_ok) {
                 print_message(msg_config_error, "name: \"%s\"; host: \"%s\"; port: \"%s\": "
@@ -284,6 +369,41 @@ void close_std(void)
     }
 }
 
+static void print_version(void)
+{
+    printf("%s %s\n", server_type, VERSION);
+#ifdef ENABLE_SANITIZER
+    printf("ENABLE_SANITIZER\n");
+#endif
+#ifdef ENABLE_REGEX
+    printf("ENABLE_REGEX\n");
+#endif
+#ifdef LIBCONFIG
+    printf("LIBCONFIG\n");
+#endif
+#ifdef SYSTEMD
+    printf("SYSTEMD\n");
+#endif
+#ifdef COV_TEST
+    printf("COV_TEST\n");
+#endif
+#ifdef HAVE_LIBWRAP
+    printf("HAVE_LIBWRAP\n");
+#endif
+#ifdef HAVE_LANDLOCK
+    printf("HAVE_LANDLOCK\n");
+#endif
+#ifdef HAVE_PROXYPROTOCOL
+    printf("HAVE_PROXYPROTOCOL\n");
+#endif
+#ifdef HAVE_LIBCAP
+    printf("HAVE_LIBCAP\n");
+#endif
+#ifdef HAVE_LIBBSD
+    printf("HAVE_LIBBSD\n");
+#endif
+}
+
 int main(int argc, char *argv[], char* envp[])
 {
    int res, num_addr_listen;
@@ -299,7 +419,7 @@ int main(int argc, char *argv[], char* envp[])
    config_finish(&cfg);
 
    if (cfg.version) {
-       printf("%s %s\n", server_type, VERSION);
+       print_version();
        exit(0);
    }
 
@@ -308,10 +428,7 @@ int main(int argc, char *argv[], char* envp[])
 
    if (cfg.inetd)
    {
-       close(fileno(stderr)); /* Make sure no error will go to client */
-       tcp_init();
-       start_shoveler(0);
-       exit(0);
+       main_inetd();  /* Does not return */
    }
 
    printsettings();

sslh-select.c

@@ -131,6 +131,7 @@ static void sigchld_process(struct loop_info* loop)
         received_sigchld = 0;
         do {
             chld = waitpid(-1, NULL, WNOHANG);
+            if ((chld == -1) && (errno == ECHILD)) return;
             CHECK_RES_RETURN(chld, "waitpid", );
             if (chld) {
                 decrease_forked_connection(loop, chld);
@@ -203,7 +204,7 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
     int i, res;
 
     setup_sigalrm();
-    loop_init(&fd_info, num_addr_listen);
+    loop_init(&fd_info, listen_sockets, num_addr_listen);
 
     watchers_init(&fd_info.watchers, listen_sockets, num_addr_listen);
 
@@ -221,8 +222,9 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
                                           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");
+        if ((res == -1) && ((errno != EAGAIN) && (errno != EINTR)))
+            print_message(msg_system_error, "%s:%d:%d:%s\n", 
+                          __FILE__, __LINE__, errno, strerror(errno));  \
 
         /* Check main socket for new connections */
         for (i = 0; i < num_addr_listen; i++) {
@@ -290,7 +292,7 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
 }
 
 
-void start_shoveler(int listen_socket) {
+void main_inetd(void) {
     print_message(msg_config_error, "inetd mode is not supported in select mode\n");
     exit(1);
 }

sslh.pod

@@ -6,7 +6,7 @@
 
 =head1 SYNOPSIS
 
-sslh [B<-F>I<config file>] [B<-t> I<num>] [B<--transparent>] [B<-p> I<listening address> [B<-p> I<listening address> ...]  [B<--tls> I<target address for TLS>] [B<--ssh> I<target address for SSH>] [B<--openvpn> I<target address for OpenVPN>] [B<--http> I<target address for HTTP>] [B<--xmpp> I<target address for XMPP>] [B<--tinc> I<target address for TINC>] [B<--anyprot> I<default target address>] [B<--on-timeout> I<protocol name>] [B<-u> I<username>] [B<-C> I<chroot>] [B<-P> I<pidfile>] [B<-v> I<n>] [-i] [-V] [-f] [-n]
+sslh [B<-F>I<config file>] [B<-t> I<num>] [B<--transparent>] [B<-p> I<listening address> [B<-p> I<listening address> ...]  [B<--tls> I<target address for TLS>] [B<--ssh> I<target address for SSH>] [B<--wireguard> I<target address for WireGuard>] [B<--openvpn> I<target address for OpenVPN>] [B<--http> I<target address for HTTP>] [B<--xmpp> I<target address for XMPP>] [B<--tinc> I<target address for TINC>] [B<--anyprot> I<default target address>] [B<--on-timeout> I<protocol name>] [B<-u> I<username>] [B<-C> I<chroot>] [B<-P> I<pidfile>] [B<-v> I<n>] [-i] [-V] [-f] [-n]
 
 =head1 DESCRIPTION
 
@@ -87,7 +87,7 @@ configuration file's settings.
 =item B<-t> I<num>, B<--timeout> I<num>
 
 Timeout before forwarding the connection to the timeout
-protocol (which should usually be SSH). Default is 2s.
+protocol (which should usually be SSH). Default is 5s.
 
 =item B<--on-timeout> I<protocol name>
 
@@ -104,7 +104,7 @@ Makes B<sslh> behave as a transparent proxy, i.e. the
 receiving service sees the original client's IP address.
 This works on Linux only and involves B<iproute2> settings.
 In some cases also B<iptables/nftables> settings are needed.
-Refer to the README or L<https://github.com/ftasnetamot/sslh/blob/2014-08-16--close-filehandles-with-detach/doc/simple_transparent_proxy.md>
+Refer to the README or L<https://github.com/yrutschle/sslh/blob/master/doc/simple_transparent_proxy.md>
 for more information.
 
 =item B<-p> I<listening address>, B<--listen> I<listening address>
@@ -136,6 +136,11 @@ If you wish to accept SSLv2, use B<--anyprot> instead.
 Interface and port on which to forward SSH connections,
 typically I<localhost:22>.
 
+=item B<--wireguard> I<target address>
+
+Interface and port on which to forward WireGuard connections,
+typically I<localhost:51820>.
+
 =item B<--openvpn> I<target address>
 
 Interface and port on which to forward OpenVPN connections,

systemd-sslh-generator.c

@@ -307,12 +307,12 @@ int main(int argc, char *argv[]) {
             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");
         }
+        if (systemd_invoked) {
+            fclose(err_log);
+        }
         return r < 0 ? -1 : 0;
     } else {
         printf("This program takes three or no arguments.\n");

t/run

@@ -10,6 +10,7 @@
 #  ./run        # run all tests
 #  ./run -l     # list all tests
 #  ./run 1 3 5  # run specified tests
+#  ./run --binary sslh-ev    # run only one binary
 
 use strict;
 use IO::Socket::INET6;
@@ -17,9 +18,13 @@ use Test::More qw/no_plan/;
 use Conf::Libconfig 1.0.3;
 use Getopt::Long;
 
-my ($coverage, $list_tests);
+# --cover: request test coverage analysis (not implemented)
+# --binary: specify which binary to run (default: all)
+# --list: list all available tests (do not run any)
+my ($coverage, $list_tests, $param_binary);
 GetOptions(
     'cover' => \$coverage,
+    'binary=s' => \$param_binary,
     'list' => \$list_tests,
 );
 
@@ -192,7 +197,8 @@ sub run_ending_test
 
 # Runs one test for one probe. Start echosrv's if required.
 # Connect to port specified in the test, otherwise to the
-# first port in the sslh configuration.
+# first port in the sslh configuration; to host specified in
+# the test, otherwise to localhost
 # run sslh, connect, write the test pattern, read the result,
 # check it connected to the right echosrv, check the data
 # was transfered ok.
@@ -206,9 +212,10 @@ sub run_test_probe
 
     my $expected = $test->{expected};
 
+    my $sslh_host = $test->{host} // "localhost";
     my $sslh_port = $test->{port} // $conf->value("listen")->[0]->{port};
-    print "test_probe [$expected] $sslh_port\n";
-    my $cnx = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
+    print "test_probe [$expected] $sslh_host:$sslh_port\n";
+    my $cnx = new IO::Socket::INET(PeerHost => "$sslh_host:$sslh_port");
     warn "t: $!\n" unless $cnx;
     return unless $cnx;
 
@@ -316,6 +323,7 @@ my @tests = (
         data_expected => "^PROXY TCP4 127.0.0.1 127.0.0.1 \\d+ \\d+\x0D\x0AINPUT_DATA",
     },
 
+
     # check socks5 does not
     {
         desc => "Server-side ProxyProtocol not active",
@@ -325,6 +333,55 @@ my @tests = (
         expected => "socks5",
     },
 
+
+    # Check proxyprotocol from IPv4 to IPv4 works.
+    {
+        desc => "Server-side IPv4 to IPv4 ProxyProtocol active",
+        host => "ip4-localhost",
+        run => \&run_test_probe,
+        cfg => "test_pp3.cfg",
+        data =>  "SSH-2.0 hello",
+        expected => "ssh",
+        data_expected => "^PROXY TCP4 127.0.0.1 127.0.0.1 \\d+ 8080\x0D\x0AINPUT_DATA",
+    },
+
+
+    # Check pp with IPv6 to IPv6 works.
+    {
+        desc => "Server-side IPv6 to IPv6 ProxyProtocol active",
+        host => "ip6-localhost",
+        run => \&run_test_probe,
+        cfg => "test_pp4.cfg",
+        data =>  "SSH-2.0 hello",
+        expected => "ssh",
+        data_expected => "^PROXY TCP6 ::ffff:127.0.0.1 ::ffff:127.0.0.1 \\d+ 8080\x0D\x0AINPUT_DATA",
+    },
+
+
+    # Check pp with IPv4 to IPv6 works.
+    {
+        desc => "Server-side IPv4 to IPv6 ProxyProtocol active",
+        host => "ip4-localhost",
+        run => \&run_test_probe,
+        cfg => "test_pp5.cfg",
+        data =>  "SSH-2.0 hello",
+        expected => "ssh",
+        data_expected => "^PROXY TCP6 ::ffff:127.0.0.1 ::ffff:127.0.0.1 \\d+ 8080\x0D\x0AINPUT_DATA",
+    },
+
+
+    # Check pp with IPv6 to IPv4 works.
+    {
+        desc => "Server-side IPv6 to IPv4 ProxyProtocol active",
+        host => "ip6-localhost",
+        run => \&run_test_probe,
+        cfg => "test_pp5.cfg",
+        data =>  "SSH-2.0 hello",
+        expected => "ssh",
+        data_expected => "^PROXY TCP6 ::ffff:127.0.0.1 ::ffff:127.0.0.1 \\d+ 8080\x0D\x0AINPUT_DATA",
+    },
+
+
     # test_pp2.cfg has proxyprotocol on port 8080
     {
         desc => "Client-side ProxyProtocol active",
@@ -388,10 +445,15 @@ if ($list_tests) {
 
 ################################################################################
 # Run selected tests
-foreach my $test (@tests) {
-    warn "Running test: $test->{desc}\n";
-    my $binary = 'sslh-ev';
-    my $code = ($test->{run})->($binary, $test);
+
+my @binaries = qw/sslh-fork sslh-select sslh-ev/;
+@binaries = $param_binary if defined $param_binary;
+
+foreach my $binary (@binaries) {
+    foreach my $test (@tests) {
+        warn "Running test: $test->{desc}\n";
+        my $code = ($test->{run})->($binary, $test);
+    }
 }
 
 stop_echosrv();

t/test_pp1.cfg

@@ -29,15 +29,15 @@ verbose-int-error: 1; # internal errors, the kind that should never happen
 # Options:
 listen:
 (
-    { host: "localhost"; port: "8080"; keepalive: true; }
+    { host: "ip4-localhost"; port: "8080"; keepalive: true; }
 );
 
 
 protocols:
 (
-     { name: "ssh";  host: "localhost"; port: "9000"; proxyprotocol: 1; },
-     { name: "socks5";  host: "localhost"; port: "9001"; },
-     { name: "anyprot";  host: "localhost"; port: "9099";  }
+     { name: "ssh";  host: "ip4-localhost"; port: "9000"; proxyprotocol: 1; },
+     { name: "socks5";  host: "ip4-localhost"; port: "9001"; },
+     { name: "anyprot";  host: "ip4-localhost"; port: "9099";  }
 );
 
 on_timeout: "ssh";

t/test_pp3.cfg

@@ -0,0 +1,44 @@
+# Testing for server-side ProxyProtocol, IPv4 to IPv4
+
+foreground: true;
+inetd: false;
+numeric: true;
+transparent: false;
+timeout: 10;   # Probe test writes slowly
+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: 1; # file descriptor activity, open/close/whatnot
+verbose-packets: 1; # hexdump packets on which probing is done
+verbose-probe-info: 1; # 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:
+listen:
+(
+    { host: "ip4-localhost"; port: "8080"; keepalive: true; }
+);
+
+
+protocols:
+(
+     { name: "ssh";  host: "ip4-localhost"; port: "9000"; proxyprotocol: 1; },
+     { name: "socks5";  host: "localhost"; port: "9001"; },
+     { name: "anyprot";  host: "localhost"; port: "9099";  }
+);
+
+on_timeout: "ssh";
+

t/test_pp4.cfg

@@ -0,0 +1,44 @@
+# Testing for server-side ProxyProtocol, IPv6 to IPv6
+
+foreground: true;
+inetd: false;
+numeric: true;
+transparent: false;
+timeout: 10;   # Probe test writes slowly
+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: 1; # file descriptor activity, open/close/whatnot
+verbose-packets: 1; # hexdump packets on which probing is done
+verbose-probe-info: 1; # 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:
+listen:
+(
+    { host: "ip6-localhost"; port: "8080"; keepalive: true; }
+);
+
+
+protocols:
+(
+     { name: "ssh";  host: "ip6-localhost"; port: "9000"; proxyprotocol: 1; },
+     { name: "socks5";  host: "ip6-localhost"; port: "9001"; },
+     { name: "anyprot";  host: "ip6-localhost"; port: "9099";  }
+);
+
+on_timeout: "ssh";
+

t/test_pp5.cfg

@@ -0,0 +1,44 @@
+# Testing for server-side ProxyProtocol, IPv4 to IPv6
+
+foreground: true;
+inetd: false;
+numeric: true;
+transparent: false;
+timeout: 10;   # Probe test writes slowly
+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: 1; # file descriptor activity, open/close/whatnot
+verbose-packets: 1; # hexdump packets on which probing is done
+verbose-probe-info: 1; # 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:
+listen:
+(
+    { host: "ip4-localhost"; port: "8080"; keepalive: true; }
+);
+
+
+protocols:
+(
+     { name: "ssh";  host: "ip6-localhost"; port: "9000"; proxyprotocol: 1; },
+     { name: "socks5";  host: "ip6-localhost"; port: "9001"; },
+     { name: "anyprot";  host: "ip6-localhost"; port: "9099";  }
+);
+
+on_timeout: "ssh";
+

t/test_pp6.cfg

@@ -0,0 +1,44 @@
+# Testing for server-side ProxyProtocol, IPv6 to IPv4
+
+foreground: true;
+inetd: false;
+numeric: true;
+transparent: false;
+timeout: 10;   # Probe test writes slowly
+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: 1; # file descriptor activity, open/close/whatnot
+verbose-packets: 1; # hexdump packets on which probing is done
+verbose-probe-info: 1; # 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:
+listen:
+(
+    { host: "ip6-localhost"; port: "8080"; keepalive: true; }
+);
+
+
+protocols:
+(
+     { name: "ssh";  host: "ip4-localhost"; port: "9000"; proxyprotocol: 1; },
+     { name: "socks5";  host: "ip6-localhost"; port: "9001"; },
+     { name: "anyprot";  host: "ip6-localhost"; port: "9099";  }
+);
+
+on_timeout: "ssh";
+

tcp-listener.c

@@ -30,14 +30,16 @@
 /* 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--;
+    if (!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++;
+    if (!gap_set(fd_info->probing_list, fd_info->num_probing, cnx)) {
+        fd_info->num_probing++;
+    }
 }
 
 /* shovels data from active fd to the other
@@ -53,7 +55,6 @@ static void shovel(struct connection *cnx, int active_fd, struct loop_info* fd_i
     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;
@@ -165,6 +166,7 @@ struct connection* accept_new_connection(struct listen_endpoint* endpoint, struc
     print_message(msg_fd, "accepting from %d\n", listen_socket);
 
     in_socket = accept(listen_socket, 0, 0);
+    if ((in_socket == -1) && (errno == EAGAIN)) return NULL;   /* Do not log if we're just retring next iteration */
     CHECK_RES_RETURN(in_socket, "accept", NULL);
 
     res = set_nonblock(in_socket);
@@ -295,13 +297,50 @@ static void connect_proxy(struct connection *cnx)
 }
 
 
+/* This ensures the kernel will close the listening socket when the
+ * parent process closes; otherwise, the listening socket is kept
+ * around by the inactive file descriptor in the child */
+void close_listen_endpoints(struct loop_info* loop)
+{
+    struct listen_endpoint* listen_sockets = loop->listen_sockets;
+    watchers* w = loop->watchers;
+
+    for (int i = 0; i < loop->num_addr_listen; i++) {
+        int fd = listen_sockets[i].socketfd;
+        watchers_del_read(w, fd);
+        watchers_del_write(w, fd);
+        close(fd);
+    }
+}
+
+
+/* Close all connections except specified.
+ * This saves file descriptors and allocated memory when forking */
+void tidy_other_connections(struct loop_info* fd_info, struct connection* keep_cnx)
+{
+    struct connection* cnx;
+    cnx_collection* cnx_coll = fd_info->collection;
+
+    for (int i = 0; i < collection_max_fd(cnx_coll); i++) {
+        cnx = collection_get_cnx_from_fd(cnx_coll, i);
+        if (cnx && (cnx != keep_cnx))
+            tidy_connection(cnx, fd_info);
+    }
+}
+
 /* Forks a shoveler process for one protocol */
 void fork_shoveling_process(struct loop_info* fd_info, struct connection* cnx) {
     pid_t pid;
+
+    if (!has_space_to_fork(fd_info)) {
+        print_message(msg_connections_error, "forking for %s: out of hash space\n", cnx->proto->name);
+        return;
+    }
+
     switch (pid = fork()) {
     case 0:  /* child */
-        /* TODO: close all file descriptors except 2 */
-        /* free(cnx); */
+        close_listen_endpoints(fd_info);
+        tidy_other_connections(fd_info, cnx);
         connect_proxy(cnx);
         exit(0);
     case -1: print_message(msg_system_error, "fork failed: err %d: %s\n", errno, strerror(errno));
@@ -311,11 +350,6 @@ void fork_shoveling_process(struct loop_info* fd_info, struct connection* cnx) {
              watcher_sigchld(fd_info, cnx, pid);
              break;
     }
-    /* Free file descriptor (used only in child), but do not reduce connection
-     * counts */
-    cnx->proto = NULL;
-    cnx->endpoint = NULL;
-    tidy_connection(cnx, fd_info);
 }
 
 /* Process read activity on a socket in probe state 
@@ -349,6 +383,11 @@ void probing_read_process(struct connection* cnx,
         tidy_connection(cnx, fd_info);
     } else if (cnx->proto->fork) {
         fork_shoveling_process(fd_info, cnx);
+        /* Free file descriptor (used only in child), but do not reduce connection
+         * counts */
+        cnx->proto = NULL;
+        cnx->endpoint = NULL;
+        tidy_connection(cnx, fd_info);
     } else {
         connect_queue(cnx, fd_info);
     }

tcp-probe.c

@@ -46,10 +46,6 @@ int probe_client_protocol(struct connection *cnx)
     if (n > 0) {
         defer_write(&cnx->q[1], buffer, n);
 
-        print_message(msg_packets, "hexdump of incoming packet:\n");
-        hexdump(msg_packets, cnx->q[1].begin_deferred_data, cnx->q[1].deferred_data_size);
-
-
         size_t pp_len = 0;
         if (cnx->endpoint->endpoint_cfg->proxyprotocol) {
             pp_len = pp_header_len(cnx->q[1].begin_deferred_data,

tls.c

@@ -277,7 +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];
-        print_message(msg_probe_error, "matching [%.*s] with [%s]\n", (int)name_len, name, *item);
+        print_message(msg_probe_info, "matching [%.*s] with [%s]\n", (int)name_len, name, *item);
         if(!fnmatch(*item, name_nullterminated, 0)) {
             free(name_nullterminated);
             return 1;

udp-listener.c

@@ -239,12 +239,11 @@ static int nonblocking_socket(struct sslhcfg_protocols_item* proto)
     }
 
     int out = socket(proto->saddr->ai_family, SOCK_DGRAM, 0);
+    CHECK_RES_RETURN(out, "udp:socket:socket", -1);
+
     res = set_nonblock(out);
-    if (res == -1) {
-        print_message(msg_system_error, "%s:%d:%s:%d:%s\n", __FILE__, __LINE__, "udp:socket:nonblock", errno, strerror(errno));
-        close(out);
-        return -1;
-    }
+    CHECK_RES_RETURN(out, "udp:socket:nonblock", -1);
+
     return out;
 }
 
@@ -273,10 +272,9 @@ struct connection* udp_c2s_forward(int sockfd, struct loop_info* fd_info)
 
     addrlen = sizeof(src_addr);
     len = recvfrom(sockfd, data, sizeof(data), 0, (struct sockaddr*) &src_addr, &addrlen);
-    if (len < 0) {
-        perror("recvfrom");
-        return NULL;
-    }
+    if ((len == -1) && ((errno == EAGAIN) || (errno == EWOULDBLOCK))) return NULL;
+    CHECK_RES_DIE(len, "udp_listener/c2s/recvfrom");
+
     target = known_source(fd_info->hash_sources, &src_addr, addrlen);
     addrinfo.ai_addr = (struct sockaddr*) &src_addr;
     addrinfo.ai_addrlen = addrlen;
@@ -337,7 +335,7 @@ void udp_s2c_forward(struct connection* cnx)
 
     res = recvfrom(sockfd, data, sizeof(data), 0, NULL, NULL);
     if ((res == -1) && ((errno == EAGAIN) || (errno == EWOULDBLOCK))) return;
-    CHECK_RES_DIE(res, "udp_listener/recvfrom");
+    CHECK_RES_DIE(res, "udp_listener/s2c/recvfrom");
     res = sendto(cnx->local_endpoint, data, res, 0,
                  (struct sockaddr*)&cnx->client_addr, cnx->addrlen);
     mark_active(cnx);

version.h

@@ -1,5 +0,0 @@
-#ifndef VERSION_H 
-#define VERSION_H 
-
-#define VERSION "v2.2.4-52-geea50a9-dirty"
-#endif