adding preliminary SDP parser

daemon/Makefile

@@ -26,7 +26,7 @@ CPPFLAGS+=      `dpkg-buildflags --get CPPFLAGS`
 LDFLAGS+=       `dpkg-buildflags --get LDFLAGS`
 
 SRCS=		main.c kernel.c poller.c aux.c control.c streambuf.c call.c control_udp.c redis.c \
-		bencode.c cookie_cache.c udp_listener.c control_ng.c
+		bencode.c cookie_cache.c udp_listener.c control_ng.c sdp.c
 OBJS=		$(SRCS:.c=.o)
 
 

daemon/sdp.c

@@ -0,0 +1,214 @@
+#include <glib.h>
+
+#include "sdp.h"
+#include "call.h"
+#include "log.h"
+
+struct string {
+	const char *s;
+	int len;
+};
+
+struct sdp_origin {
+	struct string username;
+	struct string session_id;
+	struct string version;
+	struct string network_type;
+	struct string address_type;
+	struct string address;
+	int parsed:1;
+};
+
+struct sdp_connection {
+	struct string network_type;
+	struct string address_type;
+	struct string address;
+	int parsed:1;
+};
+
+struct sdp_session {
+	struct sdp_origin origin;
+	struct sdp_connection connection;
+	GQueue media_streams;
+	GQueue attributes;
+};
+
+struct sdp_media {
+	struct string media_type;
+	struct string port;
+	struct string transport;
+	/* ... format list */
+
+	struct sdp_connection connection;
+	GQueue attributes;
+};
+
+
+
+
+static inline int extract_token(const char **sp, const char *end, struct string *out) {
+	const char *space;
+
+	out->s = *sp;
+	space = memchr(*sp, ' ', end - *sp);
+	if (space == *sp || end == *sp)
+		return -1;
+
+	if (!space) {
+		out->len = end - *sp;
+		*sp = end;
+	}
+	else {
+		out->len = space - *sp;
+		*sp = space + 1;
+	}
+	return 0;
+	
+}
+#define EXTRACT_TOKEN(field) if (extract_token(&start, end, &output->field)) return -1
+
+static int parse_origin(const char *start, const char *end, struct sdp_origin *output) {
+	if (output->parsed)
+		return -1;
+
+	EXTRACT_TOKEN(username);
+	EXTRACT_TOKEN(session_id);
+	EXTRACT_TOKEN(version);
+	EXTRACT_TOKEN(network_type);
+	EXTRACT_TOKEN(address_type);
+	EXTRACT_TOKEN(address);
+
+	output->parsed = 1;
+	return 0;
+}
+
+static int parse_connection(const char *start, const char *end, struct sdp_connection *output) {
+	if (output->parsed)
+		return -1;
+
+	EXTRACT_TOKEN(network_type);
+	EXTRACT_TOKEN(address_type);
+	EXTRACT_TOKEN(address);
+
+	output->parsed = 1;
+	return 0;
+}
+
+static int parse_media(const char *start, const char *end, struct sdp_media *output) {
+	EXTRACT_TOKEN(media_type);
+	EXTRACT_TOKEN(port);
+	EXTRACT_TOKEN(transport);
+
+	return 0;
+}
+
+GQueue *sdp_parse(const char *body, int len, GQueue *streams) {
+	const char *b, *end, *value, *line_end, *next_line;
+	struct sdp_session *session = NULL;
+	GQueue *sessions;
+	struct sdp_media *media = NULL;
+	const char *errstr;
+	struct string *attribute;
+
+	sessions = g_queue_new();
+	b = body;
+	end = body + len;
+
+	while (b && b < end - 1) {
+		errstr = "Missing '=' sign";
+		if (b[1] != '=')
+			goto error;
+
+		value = &b[2];
+		line_end = memchr(value, '\n', end - value);
+		if (!line_end) {
+			/* assume missing LF at end of body */
+			line_end = end;
+			next_line = NULL;
+		}
+		else {
+			next_line = line_end + 1;
+			if (next_line >= end)
+				next_line = NULL;
+			if (line_end[-1] == '\r')
+				line_end--;
+		}
+
+		switch (b[0]) {
+			case 'v':
+				errstr = "Error in v= line";
+				if (line_end != value + 1)
+					goto error;
+				if (value[0] != '0')
+					goto error;
+
+				session = g_slice_alloc0(sizeof(*session));
+				g_queue_init(&session->media_streams);
+				g_queue_init(&session->attributes);
+				g_queue_push_tail(sessions, session);
+				media = NULL;
+
+				break;
+
+			case 'o':
+				errstr = "o= line found within media section";
+				if (media)
+					goto error;
+				errstr = "Error parsing o= line";
+				if (parse_origin(value, line_end, &session->origin))
+					goto error;
+
+				break;
+
+			case 'm':
+				media = g_slice_alloc0(sizeof(*media));
+				g_queue_init(&media->attributes);
+				errstr = "Error parsing m= line";
+				if (parse_media(value, line_end, media))
+					goto error;
+				g_queue_push_tail(&session->media_streams, media);
+				break;
+
+			case 'c':
+				errstr = "Error parsing c= line";
+				if (parse_connection(value, line_end,
+						media ? &media->connection : &session->connection))
+					goto error;
+
+				break;
+
+			case 'a':
+				attribute = g_slice_alloc(sizeof(*attribute));
+				attribute->s = value;
+				attribute->len = line_end - value;
+				g_queue_push_tail(media ? &media->attributes : &session->attributes,
+					attribute);
+				break;
+
+			case 's':
+			case 'i':
+			case 'u':
+			case 'e':
+			case 'p':
+			case 'b':
+			case 't':
+			case 'r':
+			case 'z':
+			case 'k':
+				break;
+
+			default:
+				errstr = "Unknown SDP line type found";
+				goto error;
+		}
+
+		b = next_line;
+	}
+
+	return sessions;
+
+error:
+	mylog(LOG_WARNING, "Error parsing SDP: %s", errstr);
+	/* XXX free sessions */
+	return NULL;
+}

daemon/sdp.h

@@ -0,0 +1,8 @@
+#ifndef _SDP_H_
+#define _SDP_H_
+
+#include <glib.h>
+
+GQueue *sdp_parse(const char *body, int len, GQueue *streams);
+
+#endif

tests/sdp-parse-test.c

@@ -0,0 +1,17 @@
+/* gcc -Wall -g `pkg-config glib-2.0 --cflags --libs` sdp-parse-test.c ../daemon/sdp.c -o sdp-parse-test */
+#include <glib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "../daemon/sdp.h"
+
+int main() {
+	char *sdp = "v=0\r\no=root 25669 25669 IN IP4 192.168.51.133\r\ns=session\r\nc=IN IP4 192.168.51.133\r\nt=0 0\r\nm=audio 30018 RTP/AVP 8 0 101\r\na=rtpmap:8 PCMA/8000\r\na=rtpmap:0 PCMU/8000\r\na=rtpmap:101 telephone-event/8000\r\na=fmtp:101 0-16\r\na=silenceSupp:off - - - -\r\na=ptime:20\r\na=sendrecv\r\na=nortpproxy:yes\r\n";
+	int len = strlen(sdp);
+	GQueue *ret;
+
+	ret = sdp_parse(sdp, len, NULL);
+	printf("%i stream(s)\n", g_queue_get_length(ret));
+
+	return 0;
+}