[core] Fixed group rcv buffering of ignored packet (#1804)

Haivision · Feb 11, 2021 · bdb3191 · bdb3191
1 parent 66cb7c7
commit bdb3191
Showing 1 changed file with 14 additions and 13 deletions.
diff --git a/srtcore/group.cpp b/srtcore/group.cpp
@@ -2372,21 +2372,22 @@ int CUDTGroup::recv(char* buf, int len, SRT_MSGCTRL& w_mc)
                 // by "more correct data" if found more appropriate later. But we have to
                 // copy these data anyway anywhere, even if they need to fall on the floor later.
                 int stat;
+                char extrabuf[SRT_LIVE_MAX_PLSIZE];
+                char* msgbuf = NULL;
                 if (output_size)
                 {
-                    // We have already the data, so this must fall on the floor
-                    char lostbuf[SRT_LIVE_MAX_PLSIZE];
-                    stat = ps->core().receiveMessage((lostbuf), SRT_LIVE_MAX_PLSIZE, (mctrl), CUDTUnited::ERH_RETURN);
+                    // We already have the target data in `buf`. Now reading extra data potentially redundant (to be ignored)
+                    // or AHEAD (to be buffered internally by the group)
+                    msgbuf = extrabuf;
+                    stat = ps->core().receiveMessage((extrabuf), SRT_LIVE_MAX_PLSIZE, (mctrl), CUDTUnited::ERH_RETURN);
                     HLOGC(grlog.Debug,
-                          log << "group/recv: @" << id << " IGNORED data with %" << mctrl.pktseq << " #" << mctrl.msgno
-                              << ": " << (stat <= 0 ? "(NOTHING)" : BufferStamp(lostbuf, stat)));
-                    if (stat > 0)
-                    {
-                        m_stats.recvDiscard.Update(stat);
-                    }
+                          log << "group/recv: @" << id << " EXTRACTED EXTRA data with %" << mctrl.pktseq
+                              << " #" << mctrl.msgno << ": " << (stat <= 0 ? "(NOTHING)" : BufferStamp(extrabuf, stat))
+                              << (CSeqNo::seqcmp(mctrl.pktseq, m_RcvBaseSeqNo) > 1 ? " - TO STORE" : " - TO IGNORE"));
                 }
                 else
                 {
+                    msgbuf = buf;
                     stat = ps->core().receiveMessage((buf), len, (mctrl), CUDTUnited::ERH_RETURN);
                     HLOGC(grlog.Debug,
                           log << "group/recv: @" << id << " EXTRACTED data with %" << mctrl.pktseq << " #"
@@ -2451,7 +2452,7 @@ int CUDTGroup::recv(char* buf, int len, SRT_MSGCTRL& w_mc)
                               log << "group/recv: @" << id << " %" << mctrl.pktseq << " #" << mctrl.msgno
                                   << " BEHIND base=%" << m_RcvBaseSeqNo << " - discarding");
                         // The sequence is recorded, the packet has to be discarded.
-                        // That's all.
+                        m_stats.recvDiscard.Update(stat);
                         continue;
                     }
 
@@ -2464,7 +2465,7 @@ int CUDTGroup::recv(char* buf, int len, SRT_MSGCTRL& w_mc)
                         HLOGC(grlog.Debug,
                               log << "@" << id << " %" << mctrl.pktseq << " #" << mctrl.msgno << " AHEAD base=%"
                                   << m_RcvBaseSeqNo);
-                        p->packet.assign(buf, buf + stat);
+                        p->packet.assign(msgbuf, msgbuf + stat);
                         p->mctrl = mctrl;
                         break; // Don't read from that socket anymore.
                     }
@@ -2713,8 +2714,8 @@ CUDTGroup::ReadPos* CUDTGroup::checkPacketAhead()
         {
             // The very next packet. Return it.
             HLOGC(grlog.Debug,
-                  log << "group/recv: Base %" << m_RcvBaseSeqNo << " ahead delivery POSSIBLE %" << a.mctrl.pktseq << "#"
-                      << a.mctrl.msgno << " from @" << i->first << ")");
+                  log << "group/recv: Base %" << m_RcvBaseSeqNo << " ahead delivery POSSIBLE %" << a.mctrl.pktseq
+                      << " #" << a.mctrl.msgno << " from @" << i->first << ")");
             out = &a;
         }
         else if (seqdiff < 1 && !a.packet.empty())