simple-example.c

/*
 * Copyright 2013 University of Chicago
 *  Contact: Bryce Allen
 * Copyright 2013 Collabora Ltd.
 *  Contact: Youness Alaoui
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
 * case the provisions of LGPL are applicable instead of those above. If you
 * wish to allow use of your version of this file only under the terms of the
 * LGPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replace
 * them with the notice and other provisions required by the LGPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the LGPL.
 */

/*
 * Example using libnice to negotiate a UDP connection between two clients,
 * possibly on the same network or behind different NATs and/or stateful
 * firewalls.
 *
 * Build:
 *   gcc -o simple-example simple-example.c `pkg-config --cflags --libs nice`
 *
 * Run two clients, one controlling and one controlled:
 *   simple-example 0 $(host -4 -t A stun.stunprotocol.org | awk '{ print $4 }')
 *   simple-example 1 $(host -4 -t A stun.stunprotocol.org | awk '{ print $4 }')
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

#include <agent.h>

#include <gio/gnetworking.h>

static GMainLoop *gloop;
static GIOChannel* io_stdin;
static guint stream_id;

static const gchar *candidate_type_name[] = {"host", "srflx", "prflx", "relay"};

static const gchar *state_name[] = {"disconnected", "gathering", "connecting",
    "connected", "ready", "failed"};

static int print_local_data(NiceAgent *agent, guint stream_id,
        guint component_id);
static int parse_remote_data(NiceAgent *agent, guint stream_id,
        guint component_id, char *line);
static void cb_candidate_gathering_done(NiceAgent *agent, guint stream_id,
        gpointer data);
static void cb_new_selected_pair(NiceAgent *agent, guint stream_id,
        guint component_id, gchar *lfoundation,
        gchar *rfoundation, gpointer data);
static void cb_component_state_changed(NiceAgent *agent, guint stream_id,
        guint component_id, guint state,
        gpointer data);
static void cb_nice_recv(NiceAgent *agent, guint stream_id, guint component_id,
        guint len, gchar *buf, gpointer data);
static gboolean stdin_remote_info_cb (GIOChannel *source, GIOCondition cond,
        gpointer data);
static gboolean stdin_send_data_cb (GIOChannel *source, GIOCondition cond,
        gpointer data);

int
main(int argc, char *argv[])
{
    NiceAgent *agent;
    gchar *stun_addr = NULL;
    guint stun_port = 0;
    gboolean controlling;

    // Parse arguments
    if (argc > 4 || argc < 2 || argv[1][1] != '\0') {
        fprintf(stderr, "Usage: %s 0|1 stun_addr [stun_port]\n", argv[0]);
        return EXIT_FAILURE;
    }
    controlling = argv[1][0] - '0';
    if (controlling != 0 && controlling != 1) {
        fprintf(stderr, "Usage: %s 0|1 stun_addr [stun_port]\n", argv[0]);
        return EXIT_FAILURE;
    }
    if (argc > 2) {
        stun_addr = argv[2];
        if (argc > 3)
            stun_port = atoi(argv[3]);
        else
            stun_port = 3478;

        g_debug("Using stun server '[%s]:%u'\n", stun_addr, stun_port);
    }

    g_networking_init();

    gloop = g_main_loop_new(NULL, FALSE);
#ifdef G_OS_WIN32
    io_stdin = g_io_channel_win32_new_fd(_fileno(stdin));
#else
    io_stdin = g_io_channel_unix_new(fileno(stdin));
#endif

    // Create the nice agent
    agent = nice_agent_new(g_main_loop_get_context (gloop),
            NICE_COMPATIBILITY_RFC5245);
    if (agent == NULL)
        g_error("Failed to create agent");

    // Set the STUN settings and controlling mode
    if (stun_addr) {
        g_object_set(agent, "stun-server", stun_addr, NULL);
        g_object_set(agent, "stun-server-port", stun_port, NULL);
    }
    g_object_set(agent, "controlling-mode", controlling, NULL);

    // Connect to the signals
    g_signal_connect(agent, "candidate-gathering-done",
            G_CALLBACK(cb_candidate_gathering_done), NULL);
    g_signal_connect(agent, "new-selected-pair",
            G_CALLBACK(cb_new_selected_pair), NULL);
    g_signal_connect(agent, "component-state-changed",
            G_CALLBACK(cb_component_state_changed), NULL);

    // Create a new stream with one component
    stream_id = nice_agent_add_stream(agent, 1);
    if (stream_id == 0)
        g_error("Failed to add stream");

    // Attach to the component to receive the data
    // Without this call, candidates cannot be gathered
    nice_agent_attach_recv(agent, stream_id, 1,
            g_main_loop_get_context (gloop), cb_nice_recv, NULL);

    // Start gathering local candidates
    if (!nice_agent_gather_candidates(agent, stream_id))
        g_error("Failed to start candidate gathering");

    g_debug("waiting for candidate-gathering-done signal...");

    // Run the mainloop. Everything else will happen asynchronously
    // when the candidates are done gathering.
    g_main_loop_run (gloop);

    g_main_loop_unref(gloop);
    g_object_unref(agent);
    g_io_channel_unref (io_stdin);

    return EXIT_SUCCESS;
}

    static void
cb_candidate_gathering_done(NiceAgent *agent, guint _stream_id,
        gpointer data)
{

    g_debug("SIGNAL candidate gathering done\n");

    // Candidate gathering is done. Send our local candidates on stdout
    printf("Copy this line to remote client:\n");
    printf("\n  ");
    print_local_data(agent, _stream_id, 1);
    printf("\n");

    // Listen on stdin for the remote candidate list
    printf("Enter remote data (single line, no wrapping):\n");
    g_io_add_watch(io_stdin, G_IO_IN, stdin_remote_info_cb, agent);
    printf("> ");
    fflush (stdout);
}

    static gboolean
stdin_remote_info_cb (GIOChannel *source, GIOCondition cond,
        gpointer data)
{
    NiceAgent *agent = data;
    gchar *line = NULL;
    int rval;
    gboolean ret = TRUE;

    if (g_io_channel_read_line (source, &line, NULL, NULL, NULL) ==
            G_IO_STATUS_NORMAL) {

        // Parse remote candidate list and set it on the agent
        rval = parse_remote_data(agent, stream_id, 1, line);
        if (rval == EXIT_SUCCESS) {
            // Return FALSE so we stop listening to stdin since we parsed the
            // candidates correctly
            ret = FALSE;
            g_debug("waiting for state READY or FAILED signal...");
        } else {
            fprintf(stderr, "ERROR: failed to parse remote data\n");
            printf("Enter remote data (single line, no wrapping):\n");
            printf("> ");
            fflush (stdout);
        }
        g_free (line);
    }

    return ret;
}

    static void
cb_component_state_changed(NiceAgent *agent, guint _stream_id,
        guint component_id, guint state,
        gpointer data)
{

    g_debug("SIGNAL: state changed %d %d %s[%d]\n",
            _stream_id, component_id, state_name[state], state);

    if (state == NICE_COMPONENT_STATE_CONNECTED) {
        NiceCandidate *local, *remote;

        // Get current selected candidate pair and print IP address used
        if (nice_agent_get_selected_pair (agent, _stream_id, component_id,
                    &local, &remote)) {
            gchar ipaddr[INET6_ADDRSTRLEN];

            nice_address_to_string(&local->addr, ipaddr);
            printf("\nNegotiation complete: ([%s]:%d,",
                    ipaddr, nice_address_get_port(&local->addr));
            nice_address_to_string(&remote->addr, ipaddr);
            printf(" [%s]:%d)\n", ipaddr, nice_address_get_port(&remote->addr));
        }

        // Listen to stdin and send data written to it
        printf("\nSend lines to remote (Ctrl-D to quit):\n");
        g_io_add_watch(io_stdin, G_IO_IN, stdin_send_data_cb, agent);
        printf("> ");
        fflush (stdout);
    } else if (state == NICE_COMPONENT_STATE_FAILED) {
        g_main_loop_quit (gloop);
    }
}

    static gboolean
stdin_send_data_cb (GIOChannel *source, GIOCondition cond,
        gpointer data)
{
    NiceAgent *agent = data;
    gchar *line = NULL;

    if (g_io_channel_read_line (source, &line, NULL, NULL, NULL) ==
            G_IO_STATUS_NORMAL) {
        nice_agent_send(agent, stream_id, 1, strlen(line), line);
        g_free (line);
        printf("> ");
        fflush (stdout);
    } else {
        nice_agent_send(agent, stream_id, 1, 1, "\0");
        // Ctrl-D was pressed.
        g_main_loop_quit (gloop);
    }

    return TRUE;
}

    static void
cb_new_selected_pair(NiceAgent *agent, guint _stream_id,
        guint component_id, gchar *lfoundation,
        gchar *rfoundation, gpointer data)
{
    g_debug("SIGNAL: selected pair %s %s", lfoundation, rfoundation);
}

    static void
cb_nice_recv(NiceAgent *agent, guint _stream_id, guint component_id,
        guint len, gchar *buf, gpointer data)
{
    if (len == 1 && buf[0] == '\0')
        g_main_loop_quit (gloop);
    printf("%.*s", len, buf);
    fflush(stdout);
}

    static NiceCandidate *
parse_candidate(char *scand, guint _stream_id)
{
    NiceCandidate *cand = NULL;
    NiceCandidateType ntype;
    gchar **tokens = NULL;
    guint i;

    tokens = g_strsplit (scand, ",", 5);
    for (i = 0; tokens[i]; i++);
    if (i != 5)
        goto end;

    for (i = 0; i < G_N_ELEMENTS (candidate_type_name); i++) {
        if (strcmp(tokens[4], candidate_type_name[i]) == 0) {
            ntype = i;
            break;
        }
    }
    if (i == G_N_ELEMENTS (candidate_type_name))
        goto end;

    cand = nice_candidate_new(ntype);
    cand->component_id = 1;
    cand->stream_id = _stream_id;
    cand->transport = NICE_CANDIDATE_TRANSPORT_UDP;
    strncpy(cand->foundation, tokens[0], NICE_CANDIDATE_MAX_FOUNDATION);
    cand->foundation[NICE_CANDIDATE_MAX_FOUNDATION - 1] = 0;
    cand->priority = atoi (tokens[1]);

    if (!nice_address_set_from_string(&cand->addr, tokens[2])) {
        g_message("failed to parse addr: %s", tokens[2]);
        nice_candidate_free(cand);
        cand = NULL;
        goto end;
    }

    nice_address_set_port(&cand->addr, atoi (tokens[3]));

end:
    g_strfreev(tokens);

    return cand;
}


    static int
print_local_data (NiceAgent *agent, guint _stream_id, guint component_id)
{
    int result = EXIT_FAILURE;
    gchar *local_ufrag = NULL;
    gchar *local_password = NULL;
    gchar ipaddr[INET6_ADDRSTRLEN];
    GSList *cands = NULL, *item;

    if (!nice_agent_get_local_credentials(agent, _stream_id,
                &local_ufrag, &local_password))
        goto end;

    cands = nice_agent_get_local_candidates(agent, _stream_id, component_id);
    if (cands == NULL)
        goto end;

    printf("%s %s", local_ufrag, local_password);

    for (item = cands; item; item = item->next) {
        NiceCandidate *c = (NiceCandidate *)item->data;

        nice_address_to_string(&c->addr, ipaddr);

        // (foundation),(prio),(addr),(port),(type)
        printf(" %s,%u,%s,%u,%s",
                c->foundation,
                c->priority,
                ipaddr,
                nice_address_get_port(&c->addr),
                candidate_type_name[c->type]);
    }
    printf("\n");
    result = EXIT_SUCCESS;

end:
    if (local_ufrag)
        g_free(local_ufrag);
    if (local_password)
        g_free(local_password);
    if (cands)
        g_slist_free_full(cands, (GDestroyNotify)&nice_candidate_free);

    return result;
}


    static int
parse_remote_data(NiceAgent *agent, guint _stream_id,
        guint component_id, char *line)
{
    GSList *remote_candidates = NULL;
    gchar **line_argv = NULL;
    const gchar *ufrag = NULL;
    const gchar *passwd = NULL;
    int result = EXIT_FAILURE;
    int i;

    line_argv = g_strsplit_set (line, " \t\n", 0);
    for (i = 0; line_argv && line_argv[i]; i++) {
        if (strlen (line_argv[i]) == 0)
            continue;

        // first two args are remote ufrag and password
        if (!ufrag) {
            ufrag = line_argv[i];
        } else if (!passwd) {
            passwd = line_argv[i];
        } else {
            // Remaining args are serialized canidates (at least one is required)
            NiceCandidate *c = parse_candidate(line_argv[i], _stream_id);

            if (c == NULL) {
                g_message("failed to parse candidate: %s", line_argv[i]);
                goto end;
            }
            remote_candidates = g_slist_prepend(remote_candidates, c);
        }
    }
    if (ufrag == NULL || passwd == NULL || remote_candidates == NULL) {
        g_message("line must have at least ufrag, password, and one candidate");
        goto end;
    }

    if (!nice_agent_set_remote_credentials(agent, _stream_id, ufrag, passwd)) {
        g_message("failed to set remote credentials");
        goto end;
    }

    // Note: this will trigger the start of negotiation.
    if (nice_agent_set_remote_candidates(agent, _stream_id, component_id,
                remote_candidates) < 1) {
        g_message("failed to set remote candidates");
        goto end;
    }

    result = EXIT_SUCCESS;

end:
    if (line_argv != NULL)
        g_strfreev(line_argv);
    if (remote_candidates != NULL)
        g_slist_free_full(remote_candidates, (GDestroyNotify)&nice_candidate_free);

    return result;
}