commit f20f1d50dfb9e6178ab06886a0e406eed289c012 Author: Friedrich Schöller Date: Wed Jul 22 23:28:52 2009 +0200 initial commit diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..ec38678 --- /dev/null +++ b/Makefile @@ -0,0 +1,68 @@ +OS = $(shell uname | tr "a-z" "A-Z") + +LDFLAGS = +CFLAGS = -c -g -D$(OS) $(OS_CFLAGS) + +ifeq ($(OS), LINUX) +TUN_DEV_FILE = tun_dev_linux.c +OS_CFLAGS = -DHAVE_LINUX_IF_TUN_H +else + +ifeq ($(OS), OPENBSD) +TUN_DEV_FILE = tun_dev_openbsd.c +else + +ifeq ($(OS), FREEBSD) +TUN_DEV_FILE = tun_dev_freebsd.c +else + +TUN_DEV_FILE = tun_dev_generic.c + +endif +endif +endif + + +all: hans + +hans: tun.o sha1.o main.o client.o server.o auth.o worker.o time.o tun_dev.o echo.o exception.o utility.o + g++ -o hans tun.o sha1.o main.o client.o server.o auth.o worker.o time.o tun_dev.o echo.o exception.o utility.o $(LDFLAGS) + +utility.o: utility.cpp utility.h + g++ -c utility.cpp $(CFLAGS) + +exception.o: exception.cpp exception.h + g++ -c exception.cpp $(CFLAGS) + +echo.o: echo.cpp echo.h exception.h + g++ -c echo.cpp $(CFLAGS) + +tun.o: tun.cpp tun.h exception.h utility.h tun_dev.h + g++ -c tun.cpp $(CFLAGS) + +tun_dev.o: $(TUN_DEV_FILE) + gcc -c $(TUN_DEV_FILE) -o tun_dev.o $(CFLAGS) + +sha1.o: sha1.cpp sha1.h + g++ -c sha1.cpp $(CFLAGS) + +main.o: main.cpp client.h server.h exception.h worker.h auth.h time.h echo.h tun.h tun_dev.h + g++ -c main.cpp $(CFLAGS) + +client.o: client.cpp client.h server.h exception.h config.h worker.h auth.h time.h echo.h tun.h tun_dev.h + g++ -c client.cpp $(CFLAGS) + +server.o: server.cpp server.h client.h utility.h config.h worker.h auth.h time.h echo.h tun.h tun_dev.h + g++ -c server.cpp $(CFLAGS) + +auth.o: auth.cpp auth.h sha1.h + g++ -c auth.cpp $(CFLAGS) + +worker.o: worker.cpp worker.h tun.h exception.h time.h echo.h tun_dev.h + g++ -c worker.cpp $(CFLAGS) + +time.o: time.cpp time.h + g++ -c time.cpp $(CFLAGS) + +clean: + rm -f tun.o sha1.o main.o client.o server.o auth.o worker.o time.o tun_dev.o echo.o exception.o utility.o hans diff --git a/auth.cpp b/auth.cpp new file mode 100644 index 0000000..4063990 --- /dev/null +++ b/auth.cpp @@ -0,0 +1,65 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#include "auth.h" +#include "sha1.h" + +#include +#include + +bool Auth::randInitialized = false; + +Auth::Auth(const char *passphrase) +{ + this->passphrase = passphrase; + + if (!randInitialized) + { + srand(time(NULL)); + randInitialized = true; + } +} + +Auth::Response Auth::getResponse(const Challenge &challenge) const +{ + SHA1 hasher; + + Response response; + + hasher << passphrase.c_str(); + hasher.Input(&challenge[0], challenge.size()); + + hasher.Result((unsigned int *)response.data); + + for (int i = 0; i < 5; i++) + response.data[i] = htonl(response.data[i]); + + return response; +} + +Auth::Challenge Auth::generateChallenge(int length) const +{ + Challenge challenge; + challenge.resize(length); + + for (int i = 0; i < length; i++) + challenge[i] = rand(); + + return challenge; +} diff --git a/auth.h b/auth.h new file mode 100644 index 0000000..922d145 --- /dev/null +++ b/auth.h @@ -0,0 +1,50 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#ifndef AUTH_H +#define AUTH_H + +#include +#include +#include + +class Auth +{ +public: + typedef std::vector Challenge; + + struct Response + { + uint32_t data[5]; + bool operator==(const Response &other) const { return memcmp(this, &other, sizeof(Response)) == 0; } + }; + + Auth(const char *passphrase); + + Challenge generateChallenge(int length) const; + Response getResponse(const Challenge &challenge) const; + +protected: + std::string passphrase; + std::string challenge; + + static bool randInitialized; +}; + +#endif diff --git a/client.cpp b/client.cpp new file mode 100644 index 0000000..22c1e45 --- /dev/null +++ b/client.cpp @@ -0,0 +1,212 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#include "client.h" +#include "server.h" +#include "exception.h" +#include "config.h" + +#include +#include +#include + +using namespace std; + +const Worker::TunnelHeader::Magic Client::magic("9967"); + +Client::Client(int tunnelMtu, const char *deviceName, uint32_t serverIp, int maxPolls, const char *passphrase, uid_t uid, gid_t gid) + : Worker(tunnelMtu, deviceName, false, uid, gid), auth(passphrase) +{ + this->serverIp = serverIp; + this->maxPolls = maxPolls; + + state = STATE_CLOSED; +} + +Client::~Client() +{ + +} + +void Client::sendConnectionRequest() +{ + Server::ClientConnectData *connectData = (Server::ClientConnectData *)payloadBuffer(); + connectData->maxPolls = maxPolls; + + syslog(LOG_DEBUG, "sending connection request"); + + sendEchoToServer(TunnelHeader::TYPE_CONNECTION_REQUEST, sizeof(Server::ClientConnectData)); + + state = STATE_CONNECTION_REQUEST_SENT; + setTimeout(5000); +} + +void Client::sendChallengeResponse(int dataLength) +{ + if (dataLength != CHALLENGE_SIZE) + throw Exception("invalid challenge received"); + + state = STATE_CHALLENGE_RESPONSE_SENT; + + syslog(LOG_DEBUG, "sending challenge response"); + + vector challenge; + challenge.resize(dataLength); + memcpy(&challenge[0], payloadBuffer(), dataLength); + + Auth::Response response = auth.getResponse(challenge); + + memcpy(payloadBuffer(), (char *)&response, sizeof(Auth::Response)); + sendEchoToServer(TunnelHeader::TYPE_CHALLENGE_RESPONSE, sizeof(Auth::Response)); + + setTimeout(5000); +} + +bool Client::handleEchoData(TunnelHeader header, int dataLength, uint32_t realIp, bool reply, int id, int seq) +{ + if (realIp != serverIp || !reply || id != ICMP_ID) + return false; + + if (header.magic != Server::magic) + return false; + + switch (header.type) + { + case TunnelHeader::TYPE_RESET_CONNECTION: + syslog(LOG_DEBUG, "reset reveiced"); + sendConnectionRequest(); + return true; + case TunnelHeader::TYPE_SERVER_FULL: + if (state == STATE_CONNECTION_REQUEST_SENT) + { + throw Exception("server full"); + } + break; + case TunnelHeader::TYPE_CHALLENGE: + if (state == STATE_CONNECTION_REQUEST_SENT) + { + syslog(LOG_DEBUG, "challenge received"); + sendChallengeResponse(dataLength); + return true; + } + break; + case TunnelHeader::TYPE_CONNECTION_ACCEPT: + if (state == STATE_CHALLENGE_RESPONSE_SENT) + { + if (dataLength != sizeof(uint32_t)) + { + throw Exception("invalid ip received"); + return true; + } + + syslog(LOG_INFO, "connection established"); + + tun->setIp(ntohl(*(uint32_t *)payloadBuffer())); + state = STATE_ESTABLISHED; + + dropPrivileges(); + startPolling(); + + return true; + } + break; + case TunnelHeader::TYPE_CHALLENGE_ERROR: + if (state == STATE_CHALLENGE_RESPONSE_SENT) + { + throw Exception("password error"); + } + break; + case TunnelHeader::TYPE_DATA: + if (state == STATE_ESTABLISHED) + { + handleDataFromServer(dataLength); + return true; + } + break; + } + + syslog(LOG_DEBUG, "invalid packet type: %d, state:\n", header.type, state); + + return true; +} + +void Client::sendEchoToServer(int type, int dataLength) +{ + if (maxPolls == 0 && state == STATE_ESTABLISHED) + setTimeout(KEEP_ALIVE_INTERVAL); + + sendEcho(magic, type, dataLength, serverIp, false, ICMP_ID, 0); +} + +void Client::startPolling() +{ + if (maxPolls == 0) + { + setTimeout(KEEP_ALIVE_INTERVAL); + } + else + { + for (int i = 0; i < maxPolls; i++) + sendEchoToServer(TunnelHeader::TYPE_POLL, 0); + setTimeout(POLL_INTERVAL); + } +} + +void Client::handleDataFromServer(int dataLength) +{ + sendToTun(dataLength); + + if (maxPolls != 0) + sendEchoToServer(TunnelHeader::TYPE_POLL, 0); +} + +void Client::handleTunData(int dataLength, uint32_t sourceIp, uint32_t destIp) +{ + if (state != STATE_ESTABLISHED) + return; + + sendEchoToServer(TunnelHeader::TYPE_DATA, dataLength); +} + +void Client::handleTimeout() +{ + switch (state) + { + case STATE_CONNECTION_REQUEST_SENT: + case STATE_CHALLENGE_RESPONSE_SENT: + sendConnectionRequest(); + break; + + case STATE_ESTABLISHED: + sendEchoToServer(TunnelHeader::TYPE_POLL, 0); + setTimeout(maxPolls == 0 ? KEEP_ALIVE_INTERVAL : POLL_INTERVAL); + break; + case STATE_CLOSED: + break; + } +} + +void Client::run() +{ + now = Time::now(); + + sendConnectionRequest(); + + Worker::run(); +} diff --git a/client.h b/client.h new file mode 100644 index 0000000..dbd732f --- /dev/null +++ b/client.h @@ -0,0 +1,68 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#ifndef CLIENT_H +#define CLIENT_H + +#include "worker.h" +#include "auth.h" + +#include + +class Client : public Worker +{ +public: + Client(int tunnelMtu, const char *deviceName, uint32_t serverIp, int maxPolls, const char *passphrase, uid_t uid, gid_t gid); + virtual ~Client(); + + virtual void run(); + + static const Worker::TunnelHeader::Magic magic; +protected: + enum State + { + STATE_CLOSED, + STATE_CONNECTION_REQUEST_SENT, + STATE_CHALLENGE_RESPONSE_SENT, + STATE_ESTABLISHED + }; + + virtual bool handleEchoData(TunnelHeader header, int dataLength, uint32_t realIp, bool reply, int id, int seq); + virtual void handleTunData(int dataLength, uint32_t sourceIp, uint32_t destIp); + virtual void handleTimeout(); + + void handleDataFromServer(int length); + + void startPolling(); + + void sendEchoToServer(int type, int dataLength); + void sendChallengeResponse(int dataLength); + void sendConnectionRequest(); + + Auth auth; + + uint32_t serverIp; + + int maxPolls; + int pollTimeoutNr; + + State state; +}; + +#endif diff --git a/config.h b/config.h new file mode 100644 index 0000000..1ef0137 --- /dev/null +++ b/config.h @@ -0,0 +1,27 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#define ICMP_ID 57251 + +#define MAX_BUFFERED_PACKETS 20 + +#define KEEP_ALIVE_INTERVAL (60 * 1000) +#define POLL_INTERVAL 2000 + +#define CHALLENGE_SIZE 20 diff --git a/echo.cpp b/echo.cpp new file mode 100644 index 0000000..e016abb --- /dev/null +++ b/echo.cpp @@ -0,0 +1,107 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#include "echo.h" +#include "exception.h" + +#include + +typedef ip IpHeader; + +Echo::Echo(int maxPayloadSize) +{ + fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP); + if (fd == -1) + throw Exception("creating icmp socket", true); + + bufferSize = maxPayloadSize + headerSize(); + buffer = new char[bufferSize]; +} + +Echo::~Echo() +{ + close(fd); + delete[] buffer; +} + +int Echo::headerSize() +{ + return sizeof(IpHeader) + sizeof(EchoHeader); +} + +void Echo::send(int payloadLength, uint32_t realIp, bool reply, int id, int seq) +{ + struct sockaddr_in target; + target.sin_family = AF_INET; + target.sin_addr.s_addr = htonl(realIp); + + if (payloadLength + sizeof(IpHeader) + sizeof(EchoHeader) > bufferSize) + throw Exception("packet too big"); + + EchoHeader *header = (EchoHeader *)(buffer + sizeof(IpHeader)); + header->type = reply ? 0: 8; + header->code = 0; + header->id = htons(id); + header->seq = htons(seq); + header->chksum = 0; + header->chksum = icmpChecksum(buffer + sizeof(IpHeader), payloadLength + sizeof(EchoHeader)); + + int result = sendto(fd, buffer + sizeof(IpHeader), payloadLength + sizeof(EchoHeader), 0, (struct sockaddr *)&target, sizeof(struct sockaddr_in)); + if (result == -1) + throw Exception("sendto", true); +} + +int Echo::receive(uint32_t &realIp, bool &reply, int &id, int &seq) +{ + struct sockaddr_in source; + int source_addr_len = sizeof(struct sockaddr_in); + + int dataLength = recvfrom(fd, buffer, bufferSize, 0, (struct sockaddr *)&source, (socklen_t *)&source_addr_len); + if (dataLength == -1) + throw Exception("recvfrom", true); + + if (dataLength < sizeof(IpHeader) + sizeof(EchoHeader)) + return -1; + + EchoHeader *header = (EchoHeader *)(buffer + sizeof(IpHeader)); + if ((header->type != 0 && header->type != 8) || header->code != 0) + return -1; + + realIp = ntohl(source.sin_addr.s_addr); + reply = header->type == 0; + id = ntohs(header->id); + seq = ntohs(header->seq); + + return dataLength - sizeof(IpHeader) - sizeof(EchoHeader); +} + +uint16_t Echo::icmpChecksum(const char *data, int length) +{ + uint16_t *data16 = (uint16_t *)data; + uint32_t sum = 0; + + for (sum = 0; length > 1; length -= 2) + sum += *data16++; + if (length == 1) + sum += *(unsigned char *)data16; + + sum = (sum >> 16) + (sum & 0xffff); + sum += (sum >> 16); + return ~sum; +} diff --git a/echo.h b/echo.h new file mode 100644 index 0000000..46e508f --- /dev/null +++ b/echo.h @@ -0,0 +1,57 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#ifndef ECHO_H +#define ECHO_H + +#include +#include + +class Echo +{ +public: + Echo(int maxPayloadSize); + ~Echo(); + + int getFd() { return fd; } + + void send(int payloadLength, uint32_t realIp, bool reply, int id, int seq); + int receive(uint32_t &realIp, bool &reply, int &id, int &seq); + + char *payloadBuffer() { return buffer + headerSize(); } + + static int headerSize(); +protected: + struct EchoHeader + { + uint8_t type; + uint8_t code; + uint16_t chksum; + uint16_t id; + uint16_t seq; + }; // size = 8 + + uint16_t icmpChecksum(const char *data, int length); + + int fd; + int bufferSize; + char *buffer; +}; + +#endif diff --git a/exception.cpp b/exception.cpp new file mode 100644 index 0000000..02fa026 --- /dev/null +++ b/exception.cpp @@ -0,0 +1,38 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#include "exception.h" + +#include +#include + +using namespace std; + +Exception::Exception(const char *msg) +{ + this->msg = msg; +} + +Exception::Exception(const char *msg, bool appendSystemError) +{ + if (appendSystemError) + this->msg = string(msg) + ": " + strerror(errno); + else + this->msg = msg; +} diff --git a/exception.h b/exception.h new file mode 100644 index 0000000..e103206 --- /dev/null +++ b/exception.h @@ -0,0 +1,31 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#include + +class Exception +{ +public: + Exception(const char *msg); + Exception(const char *msg, bool appendSystemError); + + const char *errorMessage() const { return msg.c_str(); } +protected: + std::string msg; +}; diff --git a/gpl.txt b/gpl.txt new file mode 100644 index 0000000..94a9ed0 --- /dev/null +++ b/gpl.txt @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/main.cpp b/main.cpp new file mode 100644 index 0000000..601f9bd --- /dev/null +++ b/main.cpp @@ -0,0 +1,178 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#include "client.h" +#include "server.h" +#include "exception.h" + +#include +#include +#include +#include +#include +#include +#include +#include + +void usage() +{ + printf( + "usage: hans -s network [-fhr] [-p password] [-u unprivileged_user] [-d tun_device] [-m mtu]\n" + " hans -c server [-fhw] [-p password] [-u unprivileged_user] [-d tun_device] [-m mtu]\n"); +} + +int main(int argc, char *argv[]) +{ + const char *serverName; + const char *userName = NULL; + const char *password = ""; + const char *device = NULL; + bool isServer = false; + bool isClient = false; + bool foreground = false; + int mtu = 1500; + int maxPolls = 10; + uint32_t network = INADDR_NONE; + bool answerPing = false; + uid_t uid = 0; + gid_t gid = 0; + + openlog(argv[0], LOG_PERROR, LOG_DAEMON); + + int c; + while ((c = getopt(argc, argv, "fhru:d:p:s:c:m:w:")) != -1) + { + switch(c) { + case 'f': + foreground = true; + break; + case 'h': + usage(); + return 0; + case 'u': + userName = optarg; + break; + case 'd': + device = optarg; + break; + case 'p': + password = strdup(optarg); + memset(optarg, 0, strlen(optarg)); + break; + case 'c': + isClient = true; + serverName = optarg; + break; + case 's': + isServer = true; + network = ntohl(inet_addr(optarg)); + break; + case 'm': + mtu = atoi(optarg); + break; + case 'w': + maxPolls = atoi(optarg); + break; + case 'r': + answerPing = true; + break; + default: + usage(); + return 1; + } + } + + mtu -= Echo::headerSize() + Worker::headerSize(); + + if (isClient == isServer) + { + usage(); + return 1; + } + + if (network == INADDR_NONE && isServer) + { + usage(); + return 1; + } + + if (maxPolls < 0 || maxPolls > 255) + { + usage(); + return 1; + } + + if (userName != NULL) + { + passwd *pw = getpwnam(userName); + + if (pw != NULL) + { + uid = pw->pw_uid; + gid = pw->pw_gid; + } + else + { + syslog(LOG_ERR, "user not found"); + return 1; + } + } + + try + { + Worker *worker; + + if (isServer) + { + worker = new Server(mtu, device, password, network, answerPing, uid, gid, 5000); + } + else + { + uint32_t serverIp = inet_addr(serverName); + if (serverIp == INADDR_NONE) + { + struct hostent* he = gethostbyname(serverName); + if (!he) + { + syslog(LOG_ERR, "gethostbyname: %s", hstrerror(h_errno)); + return 1; + } + + serverIp = *(uint32_t *)he->h_addr; + } + + worker = new Client(mtu, device, ntohl(serverIp), maxPolls, password, uid, gid); + } + + if (!foreground) + { + syslog(LOG_INFO, "detaching from terminal"); + daemon(0, 0); + } + + worker->run(); + } + catch (Exception e) + { + syslog(LOG_ERR, "%s", e.errorMessage()); + return 1; + } + + return 0; +} diff --git a/server.cpp b/server.cpp new file mode 100644 index 0000000..373b685 --- /dev/null +++ b/server.cpp @@ -0,0 +1,338 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#include "server.h" +#include "client.h" +#include "config.h" +#include "utility.h" + +#include +#include +#include + +using namespace std; + +//#define DEBUG_ONLY(a) a +#define DEBUG_ONLY(a) + +const Worker::TunnelHeader::Magic Server::magic("9973"); + +Server::Server(int tunnelMtu, const char *deviceName, const char *passphrase, uint32_t network, bool answerEcho, uid_t uid, gid_t gid, int pollTimeout) + : Worker(tunnelMtu, deviceName, answerEcho, uid, gid), auth(passphrase) +{ + this->network = network & 0xffffff00; + this->pollTimeout = pollTimeout; + + tun->setIp(this->network + 1); + + dropPrivileges(); +} + +Server::~Server() +{ + +} + +void Server::handleUnknownClient(TunnelHeader &header, int dataLength, uint32_t realIp) +{ + ClientData client; + client.realIp = realIp; + client.maxPolls = 0; + +// if (header.type == TunnelHeader::TYPE_POLL) +// return; + + if (header.type != TunnelHeader::TYPE_CONNECTION_REQUEST || dataLength != sizeof(ClientConnectData)) + { + syslog(LOG_DEBUG, "invalid request %s", Utility::formatIp(realIp).c_str()); + sendReset(&client); + return; + } + + pollReceived(&client); + + ClientConnectData *connectData = (ClientConnectData *)payloadBuffer(); + + client.maxPolls = connectData->maxPolls; + client.state = ClientData::STATE_NEW; + client.tunnelIp = reserveTunnelIp(); + + syslog(LOG_DEBUG, "new client: %s (%s)\n", Utility::formatIp(client.realIp).c_str(), Utility::formatIp(client.tunnelIp).c_str()); + + if (client.tunnelIp != 0) + { + client.challenge = auth.generateChallenge(CHALLENGE_SIZE); + sendChallenge(&client); + + // add client to list + clientList.push_back(client); + clientRealIpMap[realIp] = clientList.size() - 1; + clientTunnelIpMap[client.tunnelIp] = clientList.size() - 1; + } + else + { + syslog(LOG_WARNING, "server full"); + sendEchoToClient(&client, TunnelHeader::TYPE_SERVER_FULL, 0); + } +} + +void Server::sendChallenge(ClientData *client) +{ + syslog(LOG_DEBUG, "sending challenge to: %s\n", Utility::formatIp(client->realIp).c_str()); + + memcpy(payloadBuffer(), &client->challenge[0], client->challenge.size()); + sendEchoToClient(client, TunnelHeader::TYPE_CHALLENGE, client->challenge.size()); + + client->state = ClientData::STATE_CHALLENGE_SENT; +} + +void Server::removeClient(ClientData *client) +{ + syslog(LOG_DEBUG, "removing client: %s (%s)\n", Utility::formatIp(client->realIp).c_str(), Utility::formatIp(client->tunnelIp).c_str()); + + releaseTunnelIp(client->tunnelIp); + + int nr = clientRealIpMap[client->realIp]; + + clientRealIpMap.erase(client->realIp); + clientTunnelIpMap.erase(client->tunnelIp); + + clientList.erase(clientList.begin() + nr); +} + +void Server::checkChallenge(ClientData *client, int length) +{ + Auth::Response rightResponse = auth.getResponse(client->challenge); + + if (length != sizeof(Auth::Response) || memcmp(&rightResponse, payloadBuffer(), length) != 0) + { + syslog(LOG_DEBUG, "wrong challenge response\n"); + + sendEchoToClient(client, TunnelHeader::TYPE_CHALLENGE_ERROR, 0); + + removeClient(client); + return; + } + + uint32_t *ip = (uint32_t *)payloadBuffer(); + *ip = htonl(client->tunnelIp); + + sendEchoToClient(client, TunnelHeader::TYPE_CONNECTION_ACCEPT, sizeof(uint32_t)); + + client->state = ClientData::STATE_ESTABLISHED; + + syslog(LOG_INFO, "connection established: %s", Utility::formatIp(client->realIp).c_str()); +} + +void Server::sendReset(ClientData *client) +{ + syslog(LOG_DEBUG, "sending reset: %s", Utility::formatIp(client->realIp).c_str()); + sendEchoToClient(client, TunnelHeader::TYPE_RESET_CONNECTION, 0); +} + +bool Server::handleEchoData(TunnelHeader header, int dataLength, uint32_t realIp, bool reply, int id, int seq) +{ + if (reply || id != ICMP_ID) + return false; + + if (header.magic != Client::magic) + return false; + + ClientData *client = getClientByRealIp(realIp); + if (client == NULL) + { + handleUnknownClient(header, dataLength, realIp); + return true; + } + + pollReceived(client); + + switch (header.type) + { + case TunnelHeader::TYPE_CONNECTION_REQUEST: + if (client->state == ClientData::STATE_CHALLENGE_SENT) + { + sendChallenge(client); + return true; + } + + syslog(LOG_DEBUG, "reconnecting %s", Utility::formatIp(realIp).c_str()); + sendReset(client); + removeClient(client); + return true; + case TunnelHeader::TYPE_CHALLENGE_RESPONSE: + if (client->state == ClientData::STATE_CHALLENGE_SENT) + { + checkChallenge(client, dataLength); + return true; + } + break; + case TunnelHeader::TYPE_DATA: + if (client->state == ClientData::STATE_ESTABLISHED) + { + sendToTun(dataLength); + return true; + } + break; + case TunnelHeader::TYPE_POLL: + return true; + } + + syslog(LOG_DEBUG, "invalid packet from: %s, type: %d, state:\n", Utility::formatIp(realIp).c_str(), header.type, client->state); + + return true; +} + +Server::ClientData *Server::getClientByTunnelIp(uint32_t ip) +{ + ClientIpMap::iterator clientMapIterator = clientTunnelIpMap.find(ip); + if (clientMapIterator == clientTunnelIpMap.end()) + return NULL; + + return &clientList[clientMapIterator->second]; +} + +Server::ClientData *Server::getClientByRealIp(uint32_t ip) +{ + ClientIpMap::iterator clientMapIterator = clientRealIpMap.find(ip); + if (clientMapIterator == clientRealIpMap.end()) + return NULL; + + return &clientList[clientMapIterator->second]; +} + +void Server::handleTunData(int dataLength, uint32_t sourceIp, uint32_t destIp) +{ + ClientData *client = getClientByTunnelIp(destIp); + + if (client == NULL) + { + syslog(LOG_DEBUG, "unknown client: %s\n", Utility::formatIp(destIp).c_str()); + return; + } + + sendEchoToClient(client, TunnelHeader::TYPE_DATA, dataLength); +} + +void Server::pollReceived(ClientData *client) +{ + unsigned int maxSavedPolls = client->maxPolls != 0 ? client->maxPolls : 1; + + client->pollTimes.push(now); + if (client->pollTimes.size() > maxSavedPolls) + client->pollTimes.pop(); + DEBUG_ONLY(printf("poll -> %d\n", client->pollTimes.size())); + + if (client->pendingPackets.size() > 0) + { + Packet &packet = client->pendingPackets.front(); + memcpy(payloadBuffer(), &packet.data[0], packet.data.size()); + client->pendingPackets.pop(); + + DEBUG_ONLY(printf("pending packet: %d bytes\n", packet.data.size())); + sendEchoToClient(client, packet.type, packet.data.size()); + } + + client->lastActivity = now; +} + +void Server::sendEchoToClient(ClientData *client, int type, int dataLength) +{ + if (client->maxPolls == 0) + { + sendEcho(magic, type, dataLength, client->realIp, true, ICMP_ID, 0); + return; + } + + while (client->pollTimes.size() != 0) + { + Time pollTime = client->pollTimes.front(); + client->pollTimes.pop(); + + if (pollTime + POLL_INTERVAL * (client->maxPolls + 1) > now) + { + DEBUG_ONLY(printf("sending -> %d\n", client->pollTimes.size())); + sendEcho(magic, type, dataLength, client->realIp, true, ICMP_ID, 0); + return; + } + } + DEBUG_ONLY(printf("queuing -> %d\n", client->pollTimes.size())); + + if (client->pendingPackets.size() == MAX_BUFFERED_PACKETS) + { + client->pendingPackets.pop(); + syslog(LOG_WARNING, "packet dropped to %s", Utility::formatIp(client->tunnelIp).c_str()); + } + + DEBUG_ONLY(printf("packet queued: %d bytes\n", dataLength)); + + client->pendingPackets.push(Packet()); + Packet &packet = client->pendingPackets.back(); + packet.type = type; + packet.data.resize(dataLength); + memcpy(&packet.data[0], payloadBuffer(), dataLength); +} + +void Server::releaseTunnelIp(uint32_t tunnelIp) +{ + usedIps.remove(tunnelIp); +} + +void Server::handleTimeout() +{ + for (int i = 0; i < clientList.size(); i++) + { + ClientData *client = &clientList[i]; + + if (client->lastActivity + KEEP_ALIVE_INTERVAL * 2 < now) + { + syslog(LOG_DEBUG, "client timeout: %s\n", Utility::formatIp(client->realIp).c_str()); + removeClient(client); + i--; + } + } + + setTimeout(KEEP_ALIVE_INTERVAL); +} + +uint32_t Server::reserveTunnelIp() +{ + uint32_t ip = network + 2; + + list::iterator i; + for (i = usedIps.begin(); i != usedIps.end(); ++i) + { + if (*i > ip) + break; + ip = ip + 1; + } + + if (ip - network >= 255) + return 0; + + usedIps.insert(i, ip); + return ip; +} + +void Server::run() +{ + setTimeout(KEEP_ALIVE_INTERVAL); + + Worker::run(); +} diff --git a/server.h b/server.h new file mode 100644 index 0000000..4c116db --- /dev/null +++ b/server.h @@ -0,0 +1,114 @@ +/* + * Hans - IP over ICMP + * Copyright (C) 2009 Friedrich Schöller + * + * 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 3 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + +#ifndef SERVER_H +#define SERVER_H + +#include "worker.h" +#include "auth.h" + +#include +#include +#include +#include + +class Server : public Worker +{ +public: + Server(int tunnelMtu, const char *deviceName, const char *passphrase, uint32_t network, bool answerEcho, uid_t uid, gid_t gid, int pollTimeout); + virtual ~Server(); + + struct ClientConnectData + { + uint8_t maxPolls; + }; + + static const Worker::TunnelHeader::Magic magic; + +protected: + struct Packet + { + int type; + std::vector data; + }; + + struct ClientData + { + enum State + { + STATE_NEW, + STATE_CHALLENGE_SENT, + STATE_ESTABLISHED + }; + + uint32_t realIp; + uint32_t tunnelIp; + + std::queue pendingPackets; + + int maxPolls; + std::queue