Make Multicast TTL for RTP configurable, patch from 'dfort'

Signed-off-by: Lennart Poettering <lennart@poettering.net>

1 files changed, 17 insertions, 2 deletions

diff --git a/src/modules/rtp/module-rtp-send.c b/src/modules/rtp/module-rtp-send.c
index 5e542253..aad21265 100644
--- a/src/modules/rtp/module-rtp-send.c
+++ b/src/modules/rtp/module-rtp-send.c
@@ -67,10 +67,12 @@ PA_MODULE_USAGE(
         "destination=<destination IP address> "
         "port=<port number> "
         "mtu=<maximum transfer unit> "
-        "loop=<loopback to local host?>"
+        "loop=<loopback to local host?> "
+        "ttl=<ttl value>"
 );
 
 #define DEFAULT_PORT 46000
+#define DEFAULT_TTL 1
 #define SAP_PORT 9875
 #define DEFAULT_DESTINATION "224.0.0.56"
 #define MEMBLOCKQ_MAXLENGTH (1024*170)
@@ -86,6 +88,7 @@ static const char* const valid_modargs[] = {
     "port",
     "mtu" ,
     "loop",
+    "ttl",
     NULL
 };
 
@@ -167,6 +170,7 @@ int pa__init(pa_module*m) {
     pa_modargs *ma = NULL;
     const char *dest;
     uint32_t port = DEFAULT_PORT, mtu;
+    unsigned char ttl = DEFAULT_TTL;
     int af, fd = -1, sap_fd = -1;
     pa_source *s;
     pa_sample_spec ss;
@@ -235,6 +239,11 @@ int pa__init(pa_module*m) {
     if (port & 1)
         pa_log_warn("Port number not even as suggested in RFC3550!");
 
+    if (pa_modargs_get_value_u32(ma, "ttl", &ttl) < 0 || ttl < 1 || ttl > 0xFF) {
+        pa_log("ttl= expects a numerical argument between 1 and 255.");
+        goto fail;
+    }
+
     dest = pa_modargs_get_value(ma, "destination", DEFAULT_DESTINATION);
 
     if (inet_pton(AF_INET6, dest, &sa6.sin6_addr) > 0) {
@@ -279,6 +288,11 @@ int pa__init(pa_module*m) {
         goto fail;
     }
 
+    if (ttl != DEFAULT_TTL && setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0) {
+        pa_log("IP_MULTICAST_TTL failed: %s", pa_cstrerror(errno));
+        goto fail;
+    }
+
     /* If the socket queue is full, let's drop packets */
     pa_make_fd_nonblock(fd);
     pa_make_udp_socket_low_delay(fd);
@@ -290,6 +304,7 @@ int pa__init(pa_module*m) {
     pa_proplist_sets(data.proplist, "rtp.destination", dest);
     pa_proplist_setf(data.proplist, "rtp.mtu", "%lu", (unsigned long) mtu);
     pa_proplist_setf(data.proplist, "rtp.port", "%lu", (unsigned long) port);
+    pa_proplist_setf(data.proplist, "rtp.ttl", "%lu", (unsigned long) ttl);
     data.driver = __FILE__;
     data.module = m;
     data.source = s;
@@ -342,7 +357,7 @@ int pa__init(pa_module*m) {
     pa_rtp_context_init_send(&u->rtp_context, fd, m->core->cookie, payload, pa_frame_size(&ss));
     pa_sap_context_init_send(&u->sap_context, sap_fd, p);
 
-    pa_log_info("RTP stream initialized with mtu %u on %s:%u, SSRC=0x%08x, payload=%u, initial sequence #%u", mtu, dest, port, u->rtp_context.ssrc, payload, u->rtp_context.sequence);
+    pa_log_info("RTP stream initialized with mtu %u on %s:%u ttl=%u, SSRC=0x%08x, payload=%u, initial sequence #%u", mtu, dest, port, ttl, u->rtp_context.ssrc, payload, u->rtp_context.sequence);
     pa_log_info("SDP-Data:\n%s\nEOF", p);
 
     pa_sap_send(&u->sap_context, 0);