summaryrefslogtreecommitdiff
path: root/example/main.c
blob: e850a409b36e8deb2067c2050b1d0f23cdbcb703 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
// Simple example of a mock IP camera. Answers WebRTC offer and streams H.264.

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>

#include "jsmn.h"
#include "tinyrtc.h"

// Helper function for parsing JSON
static bool matches(const char *json, jsmntok_t *tok, const char *s) {
	if (JSMN_STRING != tok->type) return false;
	if (strlen(s) != tok->end - tok->start) return false;
	return 0 == strncmp(json + tok->start, s, tok->end - tok->start);
}

// Parses ICE candidate from stringified JSON
struct trtc_ice_candidate_t parse_ice_candidate(const char *s)
{
	struct trtc_ice_candidate_t c = { 0 };

	int i, r;
	jsmn_parser p;
	jsmntok_t t[16];
	jsmn_init(&p);

	r = jsmn_parse(&p, s, strlen(s), t, sizeof(t) / sizeof(t[0]));
	if (r < 0) {
		printf("%s:%d: failed to parse json", __func__, __LINE__);
		return c;
	}

	if (r < 1 || t[0].type != JSMN_OBJECT) {
		printf("%s:%d: object expected", __func__, __LINE__);
		return c;
	}

	for (i = 1; i < r; i++) {
		if (matches(s, &t[i], "candidate")) {
			strncpy(c.candidate, s + t[i + 1].start,
				t[i + 1].end - t[i + 1].start);
			i++;
		} else if (matches(s, &t[i], "sdpMid")) {
			strncpy(c.sdp_mid, s + t[i + 1].start,
				t[i + 1].end - t[i + 1].start);
			i++;
		} else if (matches(s, &t[i], "sdpMLineIndex")) {
			c.sdp_mline_index = atoi(s + t[i + 1].start);
			i++;
		} else if (matches(s, &t[i], "usernameFragment")) {
			strncpy(c.username_fragment, s + t[i + 1].start,
				t[i + 1].end - t[i + 1].start);
			i++;
		}
	}

	return c;
}

// (callback) Called for each discovered local ICE candidate
void on_ice_candidate(const struct trtc_ice_candidate_t c, void *arg) {
	// send ice candidate over signaling channel
	printf("{"
		"\"candidate\":\"%s\","
		"\"sdpMLineIndex\":%d,"
		"\"sdpMid\":\"%s\","
		"\"usernameFragment\":null"
	"}\n", c.candidate, c.sdp_mline_index, c.sdp_mid);
}

int main(int argc, char **argv)
{
	openlog(NULL, LOG_PERROR, LOG_USER);

	// disable stdout buffering to ensure signaling messages send immediately
	setvbuf(stdout, NULL, _IONBF, 0);

	// initialize tinyrtc library
	trtc_init();

	// create peer connection
	struct trtc_config_t cfg = {
		.ice_servers = {
			{
				.urls = {
					"stun:stun.liburtc.org",
				},
			}
		}
	};
	struct trtc_peerconn_t* pc = trtc_peer_connection(cfg);
	if (!pc) {
		syslog(LOG_ERR, "trtc_peer_connection() failed");
		return -1;
	}

	trtc_set_on_ice_candidate(pc, on_ice_candidate, NULL);

	while (true) {
		int n;
		char *msg = NULL;
		size_t msglen = 0;


		if (n = getline(&msg, &msglen, stdin), -1 == n) {
			syslog(LOG_ERR, "%m");
			return -1;
		}

		// case: sdp offer
		if (strstr(msg, "\"sdp\"")) {
			// XXX trtc_set_remote_description(pc, offer);
			const char *answer = trtc_create_answer(pc);

			/* send SDP answer via stdout signaling channel */
			printf("{\"sdp\":\"%s\",\"type\":\"answer\"}\n", answer);

			trtc_set_local_description(pc, answer);

		// case: ice candidate
		} else if (strstr(msg, "\"candidate\"")) {
			struct trtc_ice_candidate_t c = parse_ice_candidate(msg);
			trtc_add_ice_candidate(pc, c);

		// case: error
		} else {
			printf("unrecognized signaling message\n");
		}
	}
	
	syslog(LOG_ERR, "terminating");

	return 0;
}