rtpsniff.c

/* vim: set ts=8 sw=4 sts=4 et: */
/*======================================================================
Copyright (C) 2008,2009,2014 OSSO B.V. <walter+rtpsniff@osso.nl>
This file is part of RTPSniff.

RTPSniff 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.

RTPSniff 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 RTPSniff.  If not, see <http://www.gnu.org/licenses/>.
======================================================================*/

#include "rtpsniff.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

static void exit_error(const char* errbuf) {
    fprintf(stderr, "RTPSniff: Initialization failed or bad command line "
                    "options. See -h for help:\n%s\n", errbuf);
    exit(EXIT_FAILURE);
}

int main(int argc, char const *const *argv) {
    char errbuf[PCAP_ERRBUF_SIZE];
    struct bpf_program fp;
    pcap_t *handle = NULL;

    struct memory_t memory = {
        .rtphash = {NULL, NULL},
        .active = 0,
        .request_switch = 0,
    };

    /* User wants help? */
    if (argc == 2 && argv[1][0] == '-' && argv[1][1] == 'h' && argv[1][2] == '\0') {
        rtpsniff_help();
        sniff_help();
        timer_help();
        out_help();
        return 0;
    }

    /* Try initialization */
    errbuf[0] = '\0';
    if (argc != 3)
        exit_error("Not the required 2 arguments");
    if ((handle = pcap_create(argv[1], errbuf)) == NULL)
        exit_error(errbuf);
    if ((pcap_set_snaplen(handle, sniff_snaplen()) != 0) ||
            (pcap_set_timeout(handle, 1000) != 0) ||
            (pcap_activate(handle) != 0) ||
            (pcap_compile(handle, &fp, argv[3], 0, PCAP_NETMASK_UNKNOWN) == -1) ||
            (pcap_setfilter(handle, &fp) == -1)) {
        fprintf(stderr, "RTPSniff: Initialization failed: %s\n", pcap_geterr(handle));
        if (handle)
            pcap_close(handle);
        exit(EXIT_FAILURE);
    }

    /* Initialize output module */
    if (out_open()) {
        if (handle)
            pcap_close(handle);
        exit(EXIT_FAILURE);
    }

    /* Initialize updater thread */
    timer_loop_bg(&memory);

    /* Start the main loop (ends on INT/HUP/TERM/QUIT or error) */
    sniff_loop(handle, &memory);

    /* Finish updater thread */
    timer_loop_stop();

    /* Finish/close open stuff */
    sniff_release(&memory.rtphash[0]);
    sniff_release(&memory.rtphash[1]);

    out_close();
    pcap_close(handle);
    return 0;
}

void rtpsniff_help() {
    printf(
        "Usage:\n"
        "  rtpsniff IFACE PCAP_FILTER\n"
        "\n"
        "  IFACE is the interface to sniff on.\n"
        "  PCAP_FILTER is the common BPF filter (e.g. 'udp').\n"
        "\n"
        "Example:\n"
        "  rtpsniff eth0 'udp and not port 53'\n"
        "\n"
    );
}