Changeset 5752 for pjproject/trunk/pjmedia/src/pjmedia/vid_stream.c

Timestamp:

Mar 8, 2018 2:01:26 AM (6 years ago)

Author:

ming

Message:

Fixed #865: More clever RTP transport remote address switch

The summary of changes:

• To solve no 2:

Add callback rtp_cb2(pjmedia_tp_cb_param *param) which allows application to get more info from the media transport, such as the packet's source address.

• To solve no 3:

Add compile time option PJMEDIA_TRANSPORT_SWITCH_REMOTE_ADDR (by default enabled). Currently, there are already runtime options PJMEDIA_UDP_NO_SRC_ADDR_CHECKING and PJMEDIA_ICE_NO_SRC_ADDR_CHECKING, but there are a few drawbacks:

• the options are not exported to the higher level, such as stream, or pjsua.
• the options are separate for each transport, UDP and ICE, there's no single option to do this.

• To solve no 1:

Using the new rtp_cb2() callback, move the functionality to check the packet's source address to the stream/video stream.
By checking the RTP pt and SSRC, there are a few advantages:

• When receiving packets from multiple sources, stream can choose the packet with the correct SSRC as advertised from the SDP, and discard the others (see also ticket #1366).
• If remote address switch is enabled, a faster switch can be achieved as soon as packet with correct ssrc is received, instead of waiting for several consecutive packets (according to setting PJMEDIA_RTP_NAT_PROBATION_CNT).

File:

• pjproject/trunk/pjmedia/src/pjmedia/vid_stream.c (modified) (5 diffs)

pjproject/trunk/pjmedia/src/pjmedia/vid_stream.c

@@ -181 +181 @@
     pj_timestamp             ts_freq;       /**< Timestamp frequency.       */
 
+    pj_sockaddr              rem_rtp_addr;  /**< Remote RTP address         */
+    unsigned                 rem_rtp_flag;  /**< Indicator flag about
+                                                 packet from this addr. 
+                                                 0=no pkt, 1=good ssrc pkts, 
+                                                 2=bad ssrc pkts            */
+    pj_sockaddr              rtp_src_addr;  /**< Actual packet src addr.    */
+    unsigned                 rtp_src_cnt;   /**< How many pkt from this addr*/
+
 #if TRACE_RC
     unsigned                 rc_total_sleep;
@@ -599 +607 @@
  * in the RTP socket. 
  */
-static void on_rx_rtp( void *data, 
-                       void *pkt,
-                       pj_ssize_t bytes_read)
-
-{
-    pjmedia_vid_stream *stream = (pjmedia_vid_stream*) data;
+static void on_rx_rtp( pjmedia_tp_cb_param *param)
+{
+    pjmedia_vid_stream *stream = (pjmedia_vid_stream*) param->user_data;
+    void *pkt = param->pkt;
+    pj_ssize_t bytes_read = param->size;
     pjmedia_vid_channel *channel = stream->dec;
     const pjmedia_rtp_hdr *hdr;
@@ -670 +677 @@
         }
 
-        if (seq_st.status.flag.badssrc) {
+        if (!stream->info.has_rem_ssrc && seq_st.status.flag.badssrc) {
             PJ_LOG(4,(channel->port.info.name.ptr,
                       "Changed RTP peer SSRC %d (previously %d)",
@@ -690 +697 @@
         pkt_discarded = PJ_TRUE;
         goto on_return;
+    }
+
+    /* See if source address of RTP packet is different than the 
+     * configured address, and check if we need to tell the
+     * media transport to switch RTP remote address.
+     */
+    if (param->src_addr) {
+        pj_bool_t badssrc = (stream->info.has_rem_ssrc &&
+                             seq_st.status.flag.badssrc);
+
+        if (pj_sockaddr_cmp(&stream->rem_rtp_addr, param->src_addr) == 0) {
+            /* We're still receiving from rem_rtp_addr. */
+            stream->rtp_src_cnt = 0;
+            stream->rem_rtp_flag = badssrc? 2: 1;
+        } else {
+            stream->rtp_src_cnt++;
+            
+            if (stream->rtp_src_cnt < PJMEDIA_RTP_NAT_PROBATION_CNT) {
+                if (stream->rem_rtp_flag == 1 ||
+                    (stream->rem_rtp_flag == 2 && badssrc))
+                {
+                    /* Only discard if:
+                     * - we have ever received packet with good ssrc from
+                     *   remote address (rem_rtp_addr), or
+                     * - we have ever received packet with bad ssrc from
+                     *   remote address and this packet also has bad ssrc.
+                     */
+                    pkt_discarded = PJ_TRUE;
+                    goto on_return;
+                }               
+                if (stream->info.has_rem_ssrc && !seq_st.status.flag.badssrc
+                    && stream->rem_rtp_flag != 1)
+                {
+                    /* Immediately switch if we receive packet with the
+                     * correct ssrc AND we never receive packets with
+                     * good ssrc from rem_rtp_addr.
+                     */
+                    param->rem_switch = PJ_TRUE;
+                }
+            } else {
+                /* Switch. We no longer receive packets from rem_rtp_addr. */
+                param->rem_switch = PJ_TRUE;
+            }
+
+            if (param->rem_switch) {
+                /* Set remote RTP address to source address */
+                pj_sockaddr_cp(&stream->rem_rtp_addr, param->src_addr);
+
+                /* Reset counter and flag */
+                stream->rtp_src_cnt = 0;
+                stream->rem_rtp_flag = badssrc? 2: 1;
+
+                /* Update RTCP peer ssrc */
+                stream->rtcp.peer_ssrc = pj_ntohl(hdr->ssrc);
+            }
+        }
     }
 
@@ -1673 +1736 @@
     att_param.user_data = stream;
     pj_sockaddr_cp(&att_param.rem_addr, &info->rem_addr);
+    pj_sockaddr_cp(&stream->rem_rtp_addr, &info->rem_addr);
     if (pj_sockaddr_has_addr(&info->rem_rtcp.addr))
         pj_sockaddr_cp(&att_param.rem_rtcp, &info->rem_rtcp);    
     att_param.addr_len = pj_sockaddr_get_len(&info->rem_addr);
-    att_param.rtp_cb = &on_rx_rtp;
+    att_param.rtp_cb2 = &on_rx_rtp;
     att_param.rtcp_cb = &on_rx_rtcp;