dtntunnel.cpp

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/*
 * dtntunnel.cpp
 *
 * Copyright (C) 2013 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include "config.h"

#include <iostream>
#include <iomanip>
#include <stdlib.h>

#ifdef HAVE_LIBDAEMON
#include <libdaemon/daemon.h>
#endif

// Base for send and receive bundle to/from the IBR-DTN daemon.
#include "ibrdtn/api/Client.h"

//  TCP client implemented as a stream.
#include <ibrcommon/net/socket.h>

// Some classes to be thread-safe.
#include "ibrcommon/thread/Mutex.h"
#include "ibrcommon/thread/MutexLock.h"
#include <ibrcommon/thread/SignalHandler.h>
#include <ibrcommon/Logger.h>

// Basic functionalities for streaming.
#include <iostream>

// A queue for bundles.
#include <queue>

#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/if_tun.h>

int tun_alloc(char *dev, short int flags) {

  struct ifreq ifr;
  int fd, err;
  char clonedev[] = "/dev/net/tun";

  /* Arguments taken by the function:
   *
   * char *dev: the name of an interface (or '\0'). MUST have enough
   *   space to hold the interface name if '\0' is passed
   * int flags: interface flags (eg, IFF_TUN etc.)
   */

   /* open the clone device */
   if( (fd = open(clonedev, O_RDWR)) < 0 ) {
     return fd;
   }

   /* preparation of the struct ifr, of type "struct ifreq" */
   memset(&ifr, 0, sizeof(ifr));

   ifr.ifr_flags = flags;   /* IFF_TUN or IFF_TAP, plus maybe IFF_NO_PI */

   if (*dev) {
     /* if a device name was specified, put it in the structure; otherwise,
      * the kernel will try to allocate the "next" device of the
      * specified type */
     strncpy(ifr.ifr_name, dev, IFNAMSIZ);
   }

   /* try to create the device */
   if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ) {
     close(fd);
     return err;
   }

  /* if the operation was successful, write back the name of the
   * interface to the variable "dev", so the caller can know
   * it. Note that the caller MUST reserve space in *dev (see calling
   * code below) */
  strcpy(dev, ifr.ifr_name);

  /* this is the special file descriptor that the caller will use to talk
   * with the virtual interface */
  return fd;
}

size_t throughput_data_up[5] = { 0, 0, 0, 0, 0 };
size_t throughput_data_down[5] = { 0, 0, 0, 0, 0 };
int throughput_pos = 0;

void add_throughput_data(ssize_t amount, int updown) {
        if (updown == 0) {
                throughput_data_down[throughput_pos] += amount;
        } else {
                throughput_data_up[throughput_pos] += amount;
        }
}

void timer_display_throughput(int) {
        float throughput_sum_up = 0;
        float throughput_sum_down = 0;

        for (int i = 0; i < 5; ++i) {
                throughput_sum_up += static_cast<float>(throughput_data_up[i]);
                throughput_sum_down += static_cast<float>(throughput_data_down[i]);
        }

        std::cout << "  up: " << setiosflags(ios::right) << setw(12) << setiosflags(ios::fixed) << setprecision(2) << (throughput_sum_up/1024) << " kB/s ";
        std::cout << "  down: " << setiosflags(ios::right) << setw(12) << setiosflags(ios::fixed) << setprecision(2) << (throughput_sum_down/1024) << " kB/s\r" << std::flush;

        throughput_pos++;
        if (throughput_pos > 4) throughput_pos = 0;

        throughput_data_up[throughput_pos] = 0;
        throughput_data_down[throughput_pos] = 0;
}

class TUN2BundleGateway : public dtn::api::Client
{
        public:
                TUN2BundleGateway(const std::string &app, ibrcommon::socketstream &stream, const std::string &ptp_dev)
                : dtn::api::Client(app, stream), _stream(stream), _fd(-1)
                {
                        char tun_name[IFNAMSIZ];

                        strcpy(tun_name, ptp_dev.c_str());
                        _fd = tun_alloc(tun_name, IFF_TUN);  /* tun interface */

                        tun_device = tun_name;

                        if (_fd == -1)
                                throw ibrcommon::Exception("Error: failed to open tun device");

                        // connect the API
                        this->connect();
                }

                virtual ~TUN2BundleGateway()
                {
                        // Close the tcp connection.
                        _stream.close();
                };

                void shutdown() {
                        if (_fd < 0) return;

                        // close client connection
                        this->close();

                        // close socket
                        ::close(_fd);
                        _fd = -1;
                }

                void process(const dtn::data::EID &endpoint, unsigned int lifetime = 60) {
                        if (_fd == -1) throw ibrcommon::Exception("Tunnel closed.");

                        char data[65536];
                        ssize_t ret = ::read(_fd, data, sizeof(data));

                        if (ret == -1) {
                                throw ibrcommon::Exception("Error: failed to read from tun device");
                        }

                        add_throughput_data(ret, 1);

                        // create a blob
                        ibrcommon::BLOB::Reference blob = ibrcommon::BLOB::create();

                        // add the data
                        blob.iostream()->write(data, ret);

                        // create a new bundle
                        dtn::data::Bundle b;

                        b.destination = endpoint;
                        b.push_back(blob);
                        b.lifetime = lifetime;

                        // transmit the packet
                        (*this) << b;
                        flush();
                }

                const std::string& getDeviceName() const
                {
                        return tun_device;
                }

        private:
                ibrcommon::socketstream &_stream;

                // file descriptor for the tun device
                int _fd;

                std::string tun_device;

                void received(const dtn::data::Bundle &b)
                {
                        ibrcommon::BLOB::Reference ref = b.find<dtn::data::PayloadBlock>().getBLOB();
                        ibrcommon::BLOB::iostream stream = ref.iostream();
                        char data[65536];
                        stream->read(data, sizeof(data));
                        size_t ret = stream->gcount();

                        if (::write(_fd, data, ret) < 0)
                        {
                                IBRCOMMON_LOGGER_TAG("Core", error) << "Error while writing" << IBRCOMMON_LOGGER_ENDL;
                        }

                        add_throughput_data(ret, 0);
                }
};

bool m_running = true;
TUN2BundleGateway *_gateway = NULL;

void term(int signal)
{
        if (signal >= 1)
        {
                m_running = false;
                if (_gateway != NULL)
                        _gateway->shutdown();
        }
}

void print_help(const char *argv0)
{
        std::cout << "-- dtntunnel (IBR-DTN) --" << std::endl;
        std::cout << "Syntax: " << argv0 << " [options] <endpoint>" << std::endl;
        std::cout << " <endpoint>       Destination of outgoing bundles" << std::endl << std::endl;
        std::cout << "* optional parameters *" << std::endl;
        std::cout << " -h               Display help message" << std::endl;
        std::cout << " -d <dev>         Virtual network device to create (default: tun0)" << std::endl;
        std::cout << " -s <name>        Application suffix of the local endpoint (default: tunnel)" << std::endl;
        std::cout << " -l <seconds>     Lifetime of each packet (default: 60)" << std::endl;
        std::cout << " -t               Show throughput" << std::endl;
#ifdef HAVE_LIBDAEMON
        std::cout << " -D               Daemonize the process" << std::endl;
        std::cout << " -k               Stop the running daemon" << std::endl;
        std::cout << " -p <file>        Store the pid in this pidfile" << std::endl;
#endif
}

#ifdef HAVE_LIBDAEMON
static char* __daemon_pidfile__ = NULL;

static const char* __daemon_pid_file_proc__(void) {
        return __daemon_pidfile__;
}
#endif

int main(int argc, char *argv[])
{
        int index;
        int c;

        std::string ptp_dev("tun0");
        std::string app_name("tunnel");
        std::string endpoint("dtn:none");
        unsigned int lifetime = 60;
        bool daemonize = false;
        bool stop_daemon = false;
        std::string pidfile;
        bool throughput = false;

        // catch process signals
        ibrcommon::SignalHandler sighandler(term);
        sighandler.handle(SIGINT);
        sighandler.handle(SIGTERM);
        sighandler.handle(SIGQUIT);

#ifdef HAVE_LIBDAEMON
        while ((c = getopt (argc, argv, "td:s:l:hDkp:")) != -1)
#else
        while ((c = getopt (argc, argv, "td:s:l:h")) != -1)
#endif
        switch (c)
        {
#ifdef HAVE_LIBDAEMON
                case 'D':
                        daemonize = true;
                        break;

                case 'k':
                        daemonize = true;
                        stop_daemon = true;
                        break;

                case 'p':
                        pidfile = optarg;
                        break;
#endif
                case 'd':
                        ptp_dev = optarg;
                        break;

                case 't':
                        throughput = true;
                        break;

                case 's':
                        app_name = optarg;
                        break;

                case 'l':
                        lifetime = atoi(optarg);
                        break;

                default:
                        print_help(argv[0]);
                        return 1;
        }

        int optindex = 0;
        for (index = optind; index < argc; ++index)
        {
                switch (optindex)
                {
                case 0:
                        endpoint = std::string(argv[index]);
                        break;
                }

                optindex++;
        }

        // print help if not enough parameters are set
        if (!stop_daemon && (optindex < 1)) { print_help(argv[0]); exit(0); }

        //initialize sighandler after possible exit call
        sighandler.initialize();

        // logging options
        //const unsigned char logopts = ibrcommon::Logger::LOG_DATETIME | ibrcommon::Logger::LOG_LEVEL;
        const unsigned char logopts = 0;

        // error filter
        const unsigned char logerr = ibrcommon::Logger::LOGGER_ERR | ibrcommon::Logger::LOGGER_CRIT;

        // logging filter, everything but debug, err and crit
        const unsigned char logstd = ibrcommon::Logger::LOGGER_ALL ^ (ibrcommon::Logger::LOGGER_DEBUG | logerr);

        // syslog filter, everything but DEBUG and NOTICE
        const unsigned char logsys = ibrcommon::Logger::LOGGER_ALL ^ (ibrcommon::Logger::LOGGER_DEBUG | ibrcommon::Logger::LOGGER_NOTICE);

#ifdef HAVE_LIBDAEMON
        if (daemonize) {
                // enable syslog logging
                ibrcommon::Logger::enableSyslog(argv[0], LOG_PID, LOG_DAEMON, logsys);
        } else
#endif
        {
                // add logging to the cout
                ibrcommon::Logger::addStream(std::cout, logstd, logopts);

                // add logging to the cerr
                ibrcommon::Logger::addStream(std::cerr, logerr, logopts);
        }

#ifdef HAVE_LIBDAEMON
        if (daemonize)
        {
#ifdef HAVE_DAEMON_RESET_SIGS
                /* Reset signal handlers */
                if (daemon_reset_sigs(-1) < 0) {
                        IBRCOMMON_LOGGER_TAG("Core", error) << "Failed to reset all signal handlers: " << strerror(errno) << IBRCOMMON_LOGGER_ENDL;
                        return 1;
                }

                /* Unblock signals */
                if (daemon_unblock_sigs(-1) < 0) {
                        IBRCOMMON_LOGGER_TAG("Core", error) << "Failed to unblock all signals: " << strerror(errno) << IBRCOMMON_LOGGER_ENDL;
                        return 1;
                }
#endif
                pid_t pid;

                /* Set identification string for the daemon for both syslog and PID file */
                daemon_pid_file_ident = daemon_log_ident = daemon_ident_from_argv0(argv[0]);

                /* set the pid file path */
                if (pidfile.length() > 0) {
                        __daemon_pidfile__ = new char[pidfile.length() + 1];
                        ::strcpy(__daemon_pidfile__, pidfile.c_str());
                        daemon_pid_file_proc = __daemon_pid_file_proc__;
                }

                /* Check if we are called with -k parameter */
                if (stop_daemon)
                {
                        int ret;

                        /* Kill daemon with SIGTERM */

                        /* Check if the new function daemon_pid_file_kill_wait() is available, if it is, use it. */
                        if ((ret = daemon_pid_file_kill_wait(SIGTERM, 5)) < 0)
                                IBRCOMMON_LOGGER_TAG("Core", warning) << "Failed to kill daemon: " << strerror(errno) << IBRCOMMON_LOGGER_ENDL;

                        return ret < 0 ? 1 : 0;
                }

                /* Check that the daemon is not rung twice a the same time */
                if ((pid = daemon_pid_file_is_running()) >= 0) {
                        IBRCOMMON_LOGGER_TAG("Core", error) << "Daemon already running on PID file " << pid << IBRCOMMON_LOGGER_ENDL;
                        return 1;
                }

                /* Prepare for return value passing from the initialization procedure of the daemon process */
                if (daemon_retval_init() < 0) {
                        IBRCOMMON_LOGGER_TAG("Core", error) << "Failed to create pipe." << IBRCOMMON_LOGGER_ENDL;
                        return 1;
                }

                /* Do the fork */
                if ((pid = daemon_fork()) < 0) {

                        /* Exit on error */
                        daemon_retval_done();
                        return 1;

                } else if (pid) { /* The parent */
                        int ret;

                        /* Wait for 20 seconds for the return value passed from the daemon process */
                        if ((ret = daemon_retval_wait(20)) < 0) {
                                IBRCOMMON_LOGGER_TAG("Core", error) << "Could not recieve return value from daemon process: " << strerror(errno) << IBRCOMMON_LOGGER_ENDL;
                                return 255;
                        }

                        return ret;

                } else { /* The daemon */
                        /* Close FDs */
                        if (daemon_close_all(-1) < 0) {
                                IBRCOMMON_LOGGER_TAG("Core", error) << "Failed to close all file descriptors: " << strerror(errno) << IBRCOMMON_LOGGER_ENDL;

                                /* Send the error condition to the parent process */
                                daemon_retval_send(1);

                                /* Do a cleanup */
                                daemon_retval_send(255);
                                daemon_signal_done();
                                daemon_pid_file_remove();

                                return -1;
                        }

                        /* Create the PID file */
                        if (daemon_pid_file_create() < 0) {
                                IBRCOMMON_LOGGER_TAG("Core", error) << "Could not create PID file ( " << strerror(errno) << ")." << IBRCOMMON_LOGGER_ENDL;
                                daemon_retval_send(2);

                                /* Do a cleanup */
                                daemon_retval_send(255);
                                daemon_signal_done();
                                daemon_pid_file_remove();

                                return -1;
                        }

                /* Send OK to parent process */
                daemon_retval_send(0);
                }
        }
#endif

        IBRCOMMON_LOGGER_TAG("Core", info) << "IBR-DTN IP <-> Bundle Tunnel" << IBRCOMMON_LOGGER_ENDL;

        // create a connection to the dtn daemon
        ibrcommon::vaddress addr("localhost", 4550);
        ibrcommon::socketstream conn(new ibrcommon::tcpsocket(addr));

        try {
                // set-up tun2bundle gateway
                TUN2BundleGateway gateway(app_name, conn, ptp_dev);
                _gateway = &gateway;

                IBRCOMMON_LOGGER_TAG("Core", info) << "Local:  " << app_name << IBRCOMMON_LOGGER_ENDL;
                IBRCOMMON_LOGGER_TAG("Core", info) << "Peer:   " << endpoint << IBRCOMMON_LOGGER_ENDL;
                IBRCOMMON_LOGGER_TAG("Core", info) << "Device: " << gateway.getDeviceName() << IBRCOMMON_LOGGER_ENDL;
                IBRCOMMON_LOGGER_TAG("Core", notice) << IBRCOMMON_LOGGER_ENDL;
                IBRCOMMON_LOGGER_TAG("Core", notice) << "Now you need to set-up the ip tunnel. You can use commands like this:" << IBRCOMMON_LOGGER_ENDL;
                IBRCOMMON_LOGGER_TAG("Core", notice) << "# sudo ip link set " << gateway.getDeviceName() << " up mtu 65535" << IBRCOMMON_LOGGER_ENDL;
                IBRCOMMON_LOGGER_TAG("Core", notice) << "# sudo ip addr add 10.0.0.1/24 dev " << gateway.getDeviceName() << IBRCOMMON_LOGGER_ENDL;
                IBRCOMMON_LOGGER_TAG("Core", notice) << IBRCOMMON_LOGGER_ENDL;

                timer_t timerid;
                struct sigevent sev;

                if (!daemonize && throughput) {
                        // enable throughput timer
                        signal(SIGRTMIN, timer_display_throughput);

                        sev.sigev_notify = SIGEV_SIGNAL;
                        sev.sigev_signo = SIGRTMIN;
                        sev.sigev_value.sival_ptr = &timerid;

                        // create a timer
                        timer_create(CLOCK_MONOTONIC, &sev, &timerid);

                        // arm the timer
                        struct itimerspec its;
                        size_t freq_nanosecs = 200000000;
                        its.it_value.tv_sec = freq_nanosecs / 1000000000;;
                        its.it_value.tv_nsec = freq_nanosecs % 1000000000;
                        its.it_interval.tv_sec = its.it_value.tv_sec;
                        its.it_interval.tv_nsec = its.it_value.tv_nsec;

                        if (timer_settime(timerid, 0, &its, NULL) == -1) {
                                IBRCOMMON_LOGGER_TAG("Core", error) << "Timer set failed." << IBRCOMMON_LOGGER_ENDL;
                        }
                }

                // destination
                dtn::data::EID eid(endpoint);

                while (m_running)
                {
                        gateway.process(eid, lifetime);
                }

                gateway.shutdown();
        } catch (const ibrcommon::Exception &ex) {
                if (m_running) {
                        IBRCOMMON_LOGGER_TAG("Core", error) << ex.what() << IBRCOMMON_LOGGER_ENDL;
                        return -1;
                }
        }

#ifdef HAVE_LIBDAEMON
        if (daemonize) {
                /* Do a cleanup */
                IBRCOMMON_LOGGER_TAG("Core", info) << "Stopped" << app_name << IBRCOMMON_LOGGER_ENDL;
                daemon_retval_send(255);
                daemon_signal_done();
                daemon_pid_file_remove();
        } else
#endif
        {
                std::cout << std::endl;
        }

        return 0;
}