From 0d61de758e5620a1e4a5cc89e20ec1814f9176a0 Mon Sep 17 00:00:00 2001
From: xia-chu <771730766@qq.com>
Date: Tue, 11 May 2021 12:12:28 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=8C=E5=96=84nack=E4=B8=8E=E4=B8=A2?=
 =?UTF-8?q?=E5=8C=85=E9=87=8D=E4=BC=A02?=
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Content-Transfer-Encoding: 8bit

---
 webrtc/WebRtcTransport.cpp | 31 +++++++++++++++++++++++++------
 webrtc/WebRtcTransport.h   | 16 +++++++++++++---
 2 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/webrtc/WebRtcTransport.cpp b/webrtc/WebRtcTransport.cpp
index 1cd574c8..0b1f4372 100644
--- a/webrtc/WebRtcTransport.cpp
+++ b/webrtc/WebRtcTransport.cpp
@@ -429,6 +429,9 @@ void WebRtcTransportImp::onStartWebRTC() {
             }, [&ref, this](const RtpPacket::Ptr &rtp) mutable {
                 onBeforeSortedRtp(ref, rtp);
             });
+            ref.nack_ctx.setOnNack([&ref, this](const FCI_NACK &nack) mutable{
+                onNack(ref, nack);
+            });
         }
         if (m.type != TrackApplication) {
             //记录rtp ext类型与id的关系，方便接收或发送rtp时修改rtp ext id
@@ -676,14 +679,21 @@ void WebRtcTransportImp::onRtp(const char *buf, size_t len) {
     auto &info = it->second;
 
 #if 1
-    //此处模拟接受丢包
     auto header = (RtpHeader *) buf;
     auto seq = ntohs(header->seq);
-    if (seq % 10 == 0) {
-        //丢包
-        return;
+    if (info.is_common_rtp) {
+        //此处模拟接受丢包
+        if (info.media->type == TrackVideo && seq % 10 == 0) {
+            //丢包
+            DebugL << "模拟接受丢包:" << seq;
+            return;
+        } else {
+            info.nack_ctx.received(seq);
+        }
     } else {
-        info.nack_ctx.received(seq);
+        //收到重传包
+        header->ssrc = info.media->rtp_rtx_ssrc[0].ssrc;
+        InfoL << "收到重传包:" <<  seq;
     }
 #endif
 
@@ -691,6 +701,14 @@ void WebRtcTransportImp::onRtp(const char *buf, size_t len) {
     info.receiver->inputRtp(info.media->type, info.plan->sample_rate, (uint8_t *) buf, len);
 }
 
+void WebRtcTransportImp::onNack(RtpPayloadInfo &info, const FCI_NACK &nack) {
+    auto rtcp = RtcpFB::create(RTPFBType::RTCP_RTPFB_NACK, &nack, FCI_NACK::kSize);
+    rtcp->ssrc = htons(0);
+    rtcp->ssrc_media = htonl(info.media->rtp_rtx_ssrc[0].ssrc);
+    InfoL << rtcp->RtcpHeader::dumpString();
+    sendRtcpPacket((char *) rtcp.get(), rtcp->getSize(), true);
+}
+
 ///////////////////////////////////////////////////////////////////
 
 void WebRtcTransportImp::onSortedRtp(RtpPayloadInfo &info, RtpPacket::Ptr rtp) {
@@ -756,11 +774,12 @@ void WebRtcTransportImp::onSendRtp(const RtpPacket::Ptr &rtp, bool flush, bool r
 #if 0
         //此处模拟发送丢包
         if(rtp->getSeq() % 10 == 0){
+            DebugL << "模拟发送丢包:" << rtp->getSeq();
             return;
         }
 #endif
     } else {
-        WarnL << "重传rtp:" << rtp->getSeq();
+        WarnL << "rtp发送重传:" << rtp->getSeq();
     }
     sendRtpPacket(rtp->data() + RtpPacket::kRtpTcpHeaderSize, rtp->size() - RtpPacket::kRtpTcpHeaderSize, flush, info);
     _bytes_usage += rtp->size() - RtpPacket::kRtpTcpHeaderSize;
diff --git a/webrtc/WebRtcTransport.h b/webrtc/WebRtcTransport.h
index caeb80a6..beebd16c 100644
--- a/webrtc/WebRtcTransport.h
+++ b/webrtc/WebRtcTransport.h
@@ -192,6 +192,8 @@ private:
 
 class NackContext {
 public:
+    using onNack = function<void(const FCI_NACK &nack)>;
+
     void received(uint16_t seq) {
         if (!_last_max_seq && _seq.empty()) {
             _last_max_seq = seq - 1;
@@ -229,7 +231,7 @@ public:
                 for (auto i = 0; i < FCI_NACK::kBitSize; ++i) {
                     vec[i] = _seq.find(_last_max_seq + i + 2) == _seq.end();
                 }
-                onNack(FCI_NACK(_last_max_seq + 1, vec));
+                doNack(FCI_NACK(_last_max_seq + 1, vec));
                 _last_max_seq += FCI_NACK::kBitSize + 1;
                 if (_last_max_seq >= max_seq) {
                     _seq.clear();
@@ -241,11 +243,17 @@ public:
         }
     }
 
-    void onNack(const FCI_NACK &nack) {
-        InfoL << nack.dumpString() << " " << _seq.size();
+    void setOnNack(onNack cb) {
+        _cb = std::move(cb);
     }
 
 private:
+    void doNack(const FCI_NACK &nack) {
+        if (_cb) {
+            _cb(nack);
+        }
+    }
+
     void eraseFrontSeq(){
         //前面部分seq是连续的，未丢包，移除之
         for (auto it = _seq.begin(); it != _seq.end();) {
@@ -259,6 +267,7 @@ private:
     }
 
 private:
+    onNack _cb;
     set<uint16_t> _seq;
     uint16_t _last_max_seq = 0;
 };
@@ -343,6 +352,7 @@ private:
 
     void onSortedRtp(RtpPayloadInfo &info, RtpPacket::Ptr rtp);
     void onBeforeSortedRtp(RtpPayloadInfo &info, const RtpPacket::Ptr &rtp);
+    void onNack(RtpPayloadInfo &info, const FCI_NACK &nack);
 
 private:
     //用掉的总流量