[core] drop packets in the new recv buffer by group recv base

Author: gou4shi1

srtcore/buffer_rcv.cpp

@@ -161,15 +161,10 @@ int CRcvBufferNew::insert(CUnit* unit)
 
 int CRcvBufferNew::dropUpTo(int32_t seqno)
 {
-    // Can drop only when nothing to read, and 
-    // first unacknowledged packet is missing.
-    SRT_ASSERT(m_iStartPos == m_iFirstNonreadPos);
-
     IF_RCVBUF_DEBUG(ScopedLog scoped_log);
     IF_RCVBUF_DEBUG(scoped_log.ss << "CRcvBufferNew::dropUpTo: seqno " << seqno << " m_iStartSeqNo " << m_iStartSeqNo);
 
     int len = CSeqNo::seqoff(m_iStartSeqNo, seqno);
-    SRT_ASSERT(len > 0);
     if (len <= 0)
     {
         IF_RCVBUF_DEBUG(scoped_log.ss << ". Nothing to drop.");
@@ -180,34 +175,32 @@ int CRcvBufferNew::dropUpTo(int32_t seqno)
     if (m_iMaxPosInc < 0)
         m_iMaxPosInc = 0;
 
-    // Check that all packets being dropped are missing.
     const int iDropCnt = len;
     while (len > 0)
     {
-        if (m_entries[m_iStartPos].pUnit != NULL)
+        CUnit* pUnit = m_entries[m_iStartPos].pUnit;
+        if (pUnit != NULL)
         {
+            if (!m_tsbpd.isEnabled() && m_bMessageAPI && !pUnit->m_Packet.getMsgOrderFlag())
+                --m_numOutOfOrderPackets;
             releaseUnitInPos(m_iStartPos);
         }
-
-        if (m_entries[m_iStartPos].status != EntryState_Empty)
-        {
-            SRT_ASSERT(m_entries[m_iStartPos].status == EntryState_Drop || m_entries[m_iStartPos].status == EntryState_Read);
-            m_entries[m_iStartPos].status = EntryState_Empty;
-        }
-
+        m_entries[m_iStartPos].status = EntryState_Empty;
         SRT_ASSERT(m_entries[m_iStartPos].pUnit == NULL && m_entries[m_iStartPos].status == EntryState_Empty);
         m_iStartPos = incPos(m_iStartPos);
         --len;
     }
 
     // Update positions
     m_iStartSeqNo = seqno;
-    // Move forward if there are "read" entries.
+    // Move forward if there are "read/drop" entries.
     releaseNextFillerEntries();
     // Set nonread position to the starting position before updating,
     // because start position was increased, and preceeding packets are invalid. 
     m_iFirstNonreadPos = m_iStartPos;
     updateNonreadPos();
+    if (!m_tsbpd.isEnabled() && m_bMessageAPI)
+        updateFirstReadableOutOfOrder();
     return iDropCnt;
 }
 

srtcore/core.cpp

@@ -7706,6 +7706,36 @@ int32_t srt::CUDT::ackDataUpTo(int32_t ack)
 #endif
 }
 
+#if ENABLE_EXPERIMENTAL_BONDING && ENABLE_NEW_RCVBUFFER
+void srt::CUDT::dropToGroupRecvBase() {
+    int32_t group_recv_base = SRT_SEQNO_NONE;
+    if (m_parent->m_GroupOf)
+    {
+        // Check is first done before locking to avoid unnecessary
+        // mutex locking. The condition for this field is that it
+        // can be either never set, already reset, or ever set
+        // and possibly dangling. The re-check after lock eliminates
+        // the dangling case.
+        ScopedLock glock (uglobal().m_GlobControlLock);
+
+        // Note that getRcvBaseSeqNo() will lock m_GroupOf->m_GroupLock,
+        // but this is an intended order.
+        if (m_parent->m_GroupOf)
+            group_recv_base = m_parent->m_GroupOf->getRcvBaseSeqNo();
+    }
+    if (group_recv_base == SRT_SEQNO_NONE)
+        return;
+
+    ScopedLock lck(m_RcvBufferLock);
+    dropTooLateUpTo(CSeqNo::incseq(group_recv_base));
+    if (CSeqNo::seqcmp(group_recv_base, m_iRcvCurrSeqNo) > 0)
+    {
+        LOGC(xtlog.Note, log << "dropToGroupRecvBase: m_iRcvCurrSeqNo: %" << m_iRcvCurrSeqNo << " -> %" << group_recv_base );
+        m_iRcvCurrSeqNo = group_recv_base;
+    }
+}
+#endif
+
 namespace srt {
 #if ENABLE_HEAVY_LOGGING
 static void DebugAck(string hdr, int prev, int ack)
@@ -7901,6 +7931,10 @@ int srt::CUDT::sendCtrlAck(CPacket& ctrlpkt, int size)
     string reason = "first lost"; // just for "a reason" of giving particular % for ACK
 #endif
 
+#if ENABLE_EXPERIMENTAL_BONDING && ENABLE_NEW_RCVBUFFER
+    dropToGroupRecvBase();
+#endif
+
     {
         // If there is no loss, the ACK is the current largest sequence number plus 1;
         // Otherwise it is the smallest sequence number in the receiver loss list.

srtcore/core.h

@@ -1060,6 +1060,13 @@ class CUDT
     /// @return 
     int32_t ackDataUpTo(int32_t seq);
 
+#if ENABLE_EXPERIMENTAL_BONDING && ENABLE_NEW_RCVBUFFER
+    /// @brief Drop packets in the recv buffer behind group_recv_base.
+    /// Updates m_iRcvLastSkipAck if it's behind group_recv_base.
+    /// Updates m_iRcvCurrSeqNo if it's behind group_recv_base.
+    void dropToGroupRecvBase();
+#endif
+
     void handleKeepalive(const char* data, size_t lenghth);
 
     /// Locks m_RcvBufferLock and retrieves the available size of the receiver buffer.