udpsrc: Add network interface selection

Add network interface selection when joining multicast groups.
Useful when using the udpsrc on multihomed hosts.
Fixes #575234.

API: GstUDPSrc::multicast-iface

gst/udp/gstmultiudpsink.c

@@ -635,7 +635,7 @@ gst_multiudpsink_init_send (GstMultiUDPSink * sink)
   for (clients = sink->clients; clients; clients = g_list_next (clients)) {
     client = (GstUDPClient *) clients->data;
     if (sink->auto_multicast && gst_udp_is_multicast (&client->theiraddr))
-      gst_udp_join_group (*(client->sock), &client->theiraddr);
+      gst_udp_join_group (*(client->sock), &client->theiraddr, NULL);
   }
   return TRUE;
 
@@ -687,7 +687,7 @@ gst_multiudpsink_add_internal (GstMultiUDPSink * sink, const gchar * host,
       GST_DEBUG_OBJECT (sink, "multicast address detected");
       if (sink->auto_multicast) {
         GST_DEBUG_OBJECT (sink, "joining multicast group");
-        gst_udp_join_group (*(client->sock), &client->theiraddr);
+        gst_udp_join_group (*(client->sock), &client->theiraddr, NULL);
       }
     } else {
       GST_DEBUG_OBJECT (sink, "normal address detected");

gst/udp/gstudpnetutils.c

@@ -163,19 +163,31 @@ gst_udp_set_loop_ttl (int sockfd, gboolean loop, int ttl)
   return ret;
 }
 
+/* FIXME: Add interface selection for windows hosts.  */
 int
-gst_udp_join_group (int sockfd, struct sockaddr_storage *addr)
+gst_udp_join_group (int sockfd, struct sockaddr_storage *addr, gchar * iface)
 {
   int ret = -1;
 
   switch (addr->ss_family) {
     case AF_INET:
     {
+#ifdef G_OS_WIN32
       struct ip_mreq mreq4;
+#else
+      struct ip_mreqn mreq4;
+#endif
 
       mreq4.imr_multiaddr.s_addr =
           ((struct sockaddr_in *) addr)->sin_addr.s_addr;
+#ifdef G_OS_WIN32
       mreq4.imr_interface.s_addr = INADDR_ANY;
+#else
+      if (iface)
+        mreq4.imr_ifindex = if_nametoindex (iface);
+      else
+        mreq4.imr_ifindex = 0;  /* Pick any.  */
+#endif
 
       if ((ret =
               setsockopt (sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
@@ -192,6 +204,10 @@ gst_udp_join_group (int sockfd, struct sockaddr_storage *addr)
           &(((struct sockaddr_in6 *) addr)->sin6_addr),
           sizeof (struct in6_addr));
       mreq6.ipv6mr_interface = 0;
+#if !defined(G_OS_WIN32)
+      if (iface)
+        mreq6.ipv6mr_interface = if_nametoindex (iface);
+#endif
 
       if ((ret =
               setsockopt (sockfd, IPPROTO_IPV6, IPV6_JOIN_GROUP,

gst/udp/gstudpnetutils.h

@@ -40,6 +40,7 @@
 #else
 #include <sys/time.h>
 #include <netinet/in.h>
+#include <net/if.h>
 #include <netdb.h>
 #include <sys/socket.h>
 #include <sys/wait.h>
@@ -81,7 +82,8 @@ int gst_udp_is_multicast  (struct sockaddr_storage *addr);
 
 int gst_udp_set_loop_ttl  (int sockfd, gboolean loop, int ttl);
 
-int gst_udp_join_group    (int sockfd, struct sockaddr_storage *addr);
+int gst_udp_join_group    (int sockfd, struct sockaddr_storage *addr,
+                           gchar *iface);
 int gst_udp_leave_group   (int sockfd, struct sockaddr_storage *addr);
 
 #endif /* __GST_UDP_NET_UTILS_H__*/

gst/udp/gstudpsrc.c

@@ -142,6 +142,7 @@ GST_ELEMENT_DETAILS ("UDP packet receiver",
 
 #define UDP_DEFAULT_PORT                4951
 #define UDP_DEFAULT_MULTICAST_GROUP     "0.0.0.0"
+#define UDP_DEFAULT_MULTICAST_IFACE     NULL
 #define UDP_DEFAULT_URI                 "udp://"UDP_DEFAULT_MULTICAST_GROUP":"G_STRINGIFY(UDP_DEFAULT_PORT)
 #define UDP_DEFAULT_CAPS                NULL
 #define UDP_DEFAULT_SOCKFD              -1
@@ -158,6 +159,7 @@ enum
 
   PROP_PORT,
   PROP_MULTICAST_GROUP,
+  PROP_MULTICAST_IFACE,
   PROP_URI,
   PROP_CAPS,
   PROP_SOCKFD,
@@ -253,6 +255,10 @@ gst_udpsrc_class_init (GstUDPSrcClass * klass)
       g_param_spec_string ("multicast_group", "Multicast Group",
           "The Address of multicast group to join", UDP_DEFAULT_MULTICAST_GROUP,
           G_PARAM_READWRITE));
+  g_object_class_install_property (gobject_class, PROP_MULTICAST_IFACE,
+      g_param_spec_string ("multicast_iface", "Multicast Interface",
+          "The network interface on which to join the multicast group",
+          UDP_DEFAULT_MULTICAST_IFACE, G_PARAM_READWRITE));
   g_object_class_install_property (gobject_class, PROP_URI,
       g_param_spec_string ("uri", "URI",
           "URI in the form of udp://multicast_group:port", UDP_DEFAULT_URI,
@@ -306,6 +312,7 @@ gst_udpsrc_init (GstUDPSrc * udpsrc, GstUDPSrcClass * g_class)
   udpsrc->port = UDP_DEFAULT_PORT;
   udpsrc->sockfd = UDP_DEFAULT_SOCKFD;
   udpsrc->multi_group = g_strdup (UDP_DEFAULT_MULTICAST_GROUP);
+  udpsrc->multi_iface = g_strdup (UDP_DEFAULT_MULTICAST_IFACE);
   udpsrc->uri = g_strdup (UDP_DEFAULT_URI);
   udpsrc->buffer_size = UDP_DEFAULT_BUFFER_SIZE;
   udpsrc->timeout = UDP_DEFAULT_TIMEOUT;
@@ -334,6 +341,7 @@ gst_udpsrc_finalize (GObject * object)
   if (udpsrc->caps)
     gst_caps_unref (udpsrc->caps);
   g_free (udpsrc->multi_group);
+  g_free (udpsrc->multi_iface);
   g_free (udpsrc->uri);
 
   if (udpsrc->sockfd >= 0 && udpsrc->closefd)
@@ -667,6 +675,14 @@ gst_udpsrc_set_property (GObject * object, guint prop_id, const GValue * value,
         udpsrc->multi_group = g_value_dup_string (value);
       gst_udpsrc_update_uri (udpsrc);
       break;
+    case PROP_MULTICAST_IFACE:
+      g_free (udpsrc->multi_iface);
+
+      if (g_value_get_string (value) == NULL)
+        udpsrc->multi_iface = g_strdup (UDP_DEFAULT_MULTICAST_IFACE);
+      else
+        udpsrc->multi_iface = g_value_dup_string (value);
+      break;
     case PROP_URI:
       gst_udpsrc_set_uri (udpsrc, g_value_get_string (value));
       break;
@@ -731,6 +747,9 @@ gst_udpsrc_get_property (GObject * object, guint prop_id, GValue * value,
     case PROP_MULTICAST_GROUP:
       g_value_set_string (value, udpsrc->multi_group);
       break;
+    case PROP_MULTICAST_IFACE:
+      g_value_set_string (value, udpsrc->multi_iface);
+      break;
     case PROP_URI:
       g_value_set_string (value, udpsrc->uri);
       break;
@@ -871,7 +890,7 @@ gst_udpsrc_start (GstBaseSrc * bsrc)
 
   if (src->auto_multicast && gst_udp_is_multicast (&src->myaddr)) {
     GST_DEBUG_OBJECT (src, "joining multicast group %s", src->multi_group);
-    ret = gst_udp_join_group (src->sock.fd, &src->myaddr);
+    ret = gst_udp_join_group (src->sock.fd, &src->myaddr, src->multi_iface);
     if (ret < 0)
       goto membership;
   }

gst/udp/gstudpsrc.h

@@ -56,6 +56,7 @@ struct _GstUDPSrc {
   gchar     *uri;
   int        port;
   gchar     *multi_group;
+  gchar     *multi_iface;
   gint       ttl;
   GstCaps   *caps;
   gint       buffer_size;