RTC: For NACK, it sequence must match exactly, or it cause SRTP fail

trunk/src/app/srs_app_rtc_source.cpp

@@ -1796,11 +1796,19 @@ bool SrsRtcSendTrack::has_ssrc(uint32_t ssrc)
 
 SrsRtpPacket2* SrsRtcSendTrack::fetch_rtp_packet(uint16_t seq)
 {
-    if (rtp_queue_) {
-        return rtp_queue_->at(seq);
+    SrsRtpPacket2* pkt = rtp_queue_->at(seq);
+
+    if (pkt == NULL) {
+        return pkt;
     }
 
-    return NULL;
+    // For NACK, it sequence must match exactly, or it cause SRTP fail.
+    if (pkt->header.get_sequence() != seq) {
+        srs_trace("miss match seq=%u, pkt seq=%u", seq, pkt->header.get_sequence());
+        return NULL;
+    }
+
+    return pkt;
 }
 
 // TODO: FIXME: Should refine logs, set tracks in a time.

trunk/src/utest/srs_utest_rtc.cpp

@@ -164,6 +164,46 @@ VOID TEST(KernelRTCTest, DumpsHexToString)
     }
 }
 
+VOID TEST(KernelRTCTest, NACKFetchRTPPacket)
+{
+    SrsRtcConnection s(NULL, SrsContextId());
+    SrsRtcPlayStream play(&s, SrsContextId());
+
+    SrsRtcTrackDescription ds;
+    SrsRtcVideoSendTrack *track = new SrsRtcVideoSendTrack(&s, &ds);
+
+    // The RTP queue will free the packet.
+    if (true) {
+        SrsRtpPacket2* pkt = new SrsRtpPacket2();
+        pkt->header.set_sequence(100);
+        track->rtp_queue_->set(pkt->header.get_sequence(), pkt);
+    }
+
+    // If sequence not match, packet not found.
+    if (true) {
+        SrsRtpPacket2* pkt = track->fetch_rtp_packet(10);
+        EXPECT_TRUE(pkt == NULL);
+    }
+
+    // The sequence matched, we got the packet.
+    if (true) {
+        SrsRtpPacket2* pkt = track->fetch_rtp_packet(100);
+        EXPECT_TRUE(pkt != NULL);
+    }
+
+    // NACK special case.
+    if (true) {
+        // The sequence is the "same", 1100%1000 is 100,
+        // so we can also get it from the RTP queue.
+        SrsRtpPacket2* pkt = track->rtp_queue_->at(1100);
+        EXPECT_TRUE(pkt != NULL);
+
+        // But the track requires exactly match, so it returns NULL.
+        pkt = track->fetch_rtp_packet(1100);
+        EXPECT_TRUE(pkt == NULL);
+    }
+}
+
 extern bool srs_is_stun(const uint8_t* data, size_t size);
 extern bool srs_is_dtls(const uint8_t* data, size_t len);
 extern bool srs_is_rtp_or_rtcp(const uint8_t* data, size_t len);