[FFmpeg-devel] [PATCH] Joining a SSM multicast group using an SDP (Issue #2171)
Ed Torbett
ed.torbett at simulation-systems.co.uk
Thu Jun 27 09:53:00 CEST 2013
Hi,
Attached is a patch to resolve trac issue #2171 – Joining a SSM multicast group using an SDP.
This reads the SDP parameter specifying the source-specific multicast settings and passes that information through the RTP protocol to the underlying UDP transport protocol (where code to join source-specific multicast groups already exists). It also verifies the source address of each received RTP packet (as otherwise packets from multiple sources are processed when multiple multicast groups are joined on the same server, such as when running multiple instances of ffmpeg).
Please excuse any mistakes I’ve made in following the patching procedure, I will correct and resubmit as necessary.
Signed-off-by: Edward Torbett <ed.torbett at simulation-systems.co.uk>
--------------------------------------------------
>From 971138cbce2c2871c81464023fe2ffc346a0e54f Mon Sep 17 00:00:00 2001
From: Edward Torbett <ed.torbett at simulation-systems.co.uk>
Date: 26-Jun-2013 15:53:24
Passes Source-Specific Multicast parameters read from an sdp file through to the UDP socket code, allowing source-specific multicast streams to be correctly received. As an integral part of this change, additional checking (currently only enabled in the case of SSM streams, but probably useful in similar scenarios) has been added to the RTP protocol handler to distinguish UDP packets arriving from multiple sources to the same port and process only the expected packets (those transmitted from the expected UDP source address). This resolves an issue identified when multiple instances of FFMpeg subscribe to different Source-Specific Multicast streams but with each sharing the same destination port. Signed-off-by: Edward Torbett <ed.torbett at simulation-systems.co.uk>
diff --git a/libavformat/rtpproto.c b/libavformat/rtpproto.c
index 62ec4c9..c8b4861 100644
--- a/libavformat/rtpproto.c
+++ b/libavformat/rtpproto.c
@@ -42,7 +42,8 @@
typedef struct RTPContext {
URLContext *rtp_hd, *rtcp_hd;
- int rtp_fd, rtcp_fd;
+ int rtp_fd, rtcp_fd, ssm;
+ struct sockaddr_storage ssm_addr;
} RTPContext;
/**
@@ -75,6 +76,31 @@
return 0;
}
+static struct addrinfo* rtp_resolve_host(const char *hostname, int port,
+ int type, int family, int flags)
+{
+ struct addrinfo hints = { 0 }, *res = 0;
+ int error;
+ char sport[16];
+ const char *node = 0, *service = "0";
+
+ if (port > 0) {
+ snprintf(sport, sizeof(sport), "%d", port);
+ service = sport;
+ }
+ if ((hostname) && (hostname[0] != '\0') && (hostname[0] != '?')) {
+ node = hostname;
+ }
+ hints.ai_socktype = type;
+ hints.ai_family = family;
+ hints.ai_flags = flags;
+ if ((error = getaddrinfo(node, service, &hints, &res))) {
+ res = NULL;
+ av_log(NULL, AV_LOG_ERROR, "rtp_resolve_host: %s\n", gai_strerror(error));
+ }
+
+ return res;
+}
/**
* add option to url of the form:
@@ -98,6 +124,7 @@
static void build_udp_url(char *buf, int buf_size,
const char *hostname, int port,
+ int ssm, const char* source_addr,
int local_port, int ttl,
int max_packet_size, int connect)
{
@@ -108,6 +135,8 @@
url_add_option(buf, buf_size, "ttl=%d", ttl);
if (max_packet_size >=0)
url_add_option(buf, buf_size, "pkt_size=%d", max_packet_size);
+ if (ssm)
+ url_add_option(buf, buf_size, "sources=%s", source_addr);
if (connect)
url_add_option(buf, buf_size, "connect=1");
url_add_option(buf, buf_size, "fifo_size=0");
@@ -123,6 +152,7 @@
* 'connect=0/1' : do a connect() on the UDP socket
* deprecated option:
* 'localport=n' : set the local port to n
+ * 'ssm=ip' : use ip as source-specific multicast address
*
* if rtcpport isn't set the rtcp port will be the rtp port + 1
* if local rtp port isn't set any available port will be used for the local
@@ -136,10 +166,11 @@
int rtp_port, rtcp_port,
ttl, connect,
local_rtp_port, local_rtcp_port, max_packet_size;
- char hostname[256];
+ char hostname[256],source_ip[50];
char buf[1024];
char path[1024];
const char *p;
+ struct addrinfo *sourceaddr;
av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &rtp_port,
path, sizeof(path), uri);
@@ -149,6 +180,7 @@
local_rtp_port = -1;
local_rtcp_port = -1;
max_packet_size = -1;
+ s->ssm = 0;
connect = 0;
p = strchr(uri, '?');
@@ -174,10 +206,21 @@
if (av_find_info_tag(buf, sizeof(buf), "connect", p)) {
connect = strtol(buf, NULL, 10);
}
+ if (av_find_info_tag(buf, sizeof(buf), "ssm", p)) {
+ s->ssm = 1;
+ snprintf(source_ip, sizeof(source_ip), "%s", buf);
+
+ sourceaddr = rtp_resolve_host(source_ip, 0,
+ SOCK_DGRAM, AF_UNSPEC,
+ AI_NUMERICHOST);
+
+ memcpy(&s->ssm_addr, sourceaddr->ai_addr, sourceaddr->ai_addrlen);
+ freeaddrinfo(sourceaddr);
+ }
}
build_udp_url(buf, sizeof(buf),
- hostname, rtp_port, local_rtp_port, ttl, max_packet_size,
+ hostname, rtp_port, s->ssm, source_ip, local_rtp_port, ttl, max_packet_size,
connect);
if (ffurl_open(&s->rtp_hd, buf, flags, &h->interrupt_callback, NULL) < 0)
goto fail;
@@ -185,7 +228,7 @@
local_rtcp_port = ff_udp_get_local_port(s->rtp_hd) + 1;
build_udp_url(buf, sizeof(buf),
- hostname, rtcp_port, local_rtcp_port, ttl, max_packet_size,
+ hostname, rtcp_port, s->ssm, source_ip, local_rtcp_port, ttl, max_packet_size,
connect);
if (ffurl_open(&s->rtcp_hd, buf, flags, &h->interrupt_callback, NULL) < 0)
goto fail;
@@ -232,6 +275,27 @@
continue;
return AVERROR(EIO);
}
+ if (s->ssm) {
+ if (from.ss_family == AF_INET && s->ssm_addr.ss_family == AF_INET) {
+ uint32_t intended_source = ((struct sockaddr_in *)&s->ssm_addr)->sin_addr.s_addr;
+ uint32_t actual_source = ((struct sockaddr_in *)&from)->sin_addr.s_addr;
+ if (intended_source != actual_source) {
+ // discard the packet without any processing
+ continue;
+ }
+ }
+
+#if defined(IPPROTO_IPV6)
+ if (from.ss_family == AF_INET6 && s->ssm_addr.ss_family == AF_INET6) {
+ unsigned char* intended_source = ((struct sockaddr_in6 *)&s->ssm_addr)->sin6_addr.s6_addr;
+ unsigned char* actual_source = ((struct sockaddr_in6 *)&from)->sin6_addr.s6_addr;
+ if (memcmp(intended_source, actual_source, 16) != 0) {
+ // discard the packet without any processing
+ continue;
+ }
+ }
+#endif
+ }
break;
}
/* then RTP */
@@ -245,6 +309,27 @@
continue;
return AVERROR(EIO);
}
+ if (s->ssm) {
+ if (from.ss_family == AF_INET && s->ssm_addr.ss_family == AF_INET) {
+ uint32_t intended_source = ((struct sockaddr_in *)&s->ssm_addr)->sin_addr.s_addr;
+ uint32_t actual_source = ((struct sockaddr_in *)&from)->sin_addr.s_addr;
+ if (intended_source != actual_source) {
+ // discard the packet without any processing
+ continue;
+ }
+ }
+
+#if defined(IPPROTO_IPV6)
+ if (from.ss_family == AF_INET6 && s->ssm_addr.ss_family == AF_INET6) {
+ unsigned char* intended_source = ((struct sockaddr_in6 *)&s->ssm_addr)->sin6_addr.s6_addr;
+ unsigned char* actual_source = ((struct sockaddr_in6 *)&from)->sin6_addr.s6_addr;
+ if (memcmp(intended_source, actual_source, 16) != 0) {
+ // discard the packet without any processing
+ continue;
+ }
+ }
+#endif
+ }
break;
}
} else if (n < 0) {
diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
index 6310d79..6f531d9 100644
--- a/libavformat/rtsp.c
+++ b/libavformat/rtsp.c
@@ -497,6 +497,23 @@
p += strspn(p, SPACE_CHARS);
if (av_strstart(p, "inline:", &p))
get_word(rtsp_st->crypto_params, sizeof(rtsp_st->crypto_params), &p);
+ } else if (av_strstart(p, "source-filter", &p) && s->nb_streams > 0) {
+ get_word(buf1, sizeof(buf1), &p); // ignore tag
+
+ get_word(buf1, sizeof(buf1), &p);
+ if (strcmp(buf1, "IN") != 0)
+ return;
+ get_word(buf1, sizeof(buf1), &p);
+ if (strcmp(buf1, "IP4") && strcmp(buf1, "IP6"))
+ return;
+ get_word(buf1, sizeof(buf1), &p); //ignore repeated multicast address
+ get_word(buf1, sizeof(buf1), &p);
+ if (get_sockaddr(buf1, &sdp_ip))
+ return;
+
+ rtsp_st = rt->rtsp_streams[rt->nb_rtsp_streams - 1];
+ rtsp_st->ssm = 1;
+ rtsp_st->source_ip = sdp_ip;
} else {
if (rt->server_type == RTSP_SERVER_WMS)
ff_wms_parse_sdp_a_line(s, p);
@@ -2082,6 +2099,11 @@
"?localport=%d&ttl=%d&connect=%d", rtsp_st->sdp_port,
rtsp_st->sdp_ttl,
rt->rtsp_flags & RTSP_FLAG_FILTER_SRC ? 1 : 0);
+ if (rtsp_st->ssm) {
+ getnameinfo((struct sockaddr*) &rtsp_st->source_ip, sizeof(rtsp_st->source_ip),
+ namebuf, sizeof(namebuf), NULL, 0, NI_NUMERICHOST);
+ av_strlcatf(url, sizeof(url), "&ssm=%s", namebuf);
+ }
if (ffurl_open(&rtsp_st->rtp_handle, url, AVIO_FLAG_READ_WRITE,
&s->interrupt_callback, NULL) < 0) {
err = AVERROR_INVALIDDATA;
diff --git a/libavformat/rtsp.h b/libavformat/rtsp.h
index 4af3507..43ab28c 100644
--- a/libavformat/rtsp.h
+++ b/libavformat/rtsp.h
@@ -430,6 +430,8 @@
//@{
int sdp_port; /**< port (from SDP content) */
struct sockaddr_storage sdp_ip; /**< IP address (from SDP content) */
+ int ssm; /**< Whether the stream should use source-specific multicast or not (from SDP content) */
+ struct sockaddr_storage source_ip; /**< Source-specific multicast source IP address (from SDP content) */
int sdp_ttl; /**< IP Time-To-Live (from SDP content) */
int sdp_payload_type; /**< payload type */
//@}
More information about the ffmpeg-devel
mailing list