F5/unison
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

tcp: Prevent DupAck classification on segments with data

Browse Source 
Credits to Neal Cardwell for finding the issue.
This commit is contained in:
Tom Henderson
2024-09-12 11:42:15 +05:30
committed by Aniket Singh
parent f8e45bf7a9
commit 38055f5e6d
2 changed files with 14 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
src/internet/model/tcp-socket-base.cc
View File

@@ -1932,9 +1932,11 @@ TcpSocketBase::ReceivedAck(Ptr<Packet> packet, const TcpHeader& tcpHeader)
NS_LOG_INFO("Update bytes in flight before processing the ACK.");
BytesInFlight();
bool receivedData = packet->GetSize() > 0;
// RFC 6675 Section 5: 2nd, 3rd paragraph and point (A), (B) implementation
// are inside the function ProcessAck
ProcessAck(ackNumber, (bytesSacked > 0), currentDelivered, oldHeadSequence);
ProcessAck(ackNumber, (bytesSacked > 0), currentDelivered, oldHeadSequence, receivedData);
m_tcb->m_isRetransDataAcked = false;
if (m_congestionControl->HasCongControl())
@@ -1952,7 +1954,7 @@ TcpSocketBase::ReceivedAck(Ptr<Packet> packet, const TcpHeader& tcpHeader)
}
// If there is any data piggybacked, store it into m_rxBuffer
if (packet->GetSize() > 0)
if (receivedData)
{
ReceivedData(packet, tcpHeader);
}
@@ -1966,7 +1968,8 @@ void
TcpSocketBase::ProcessAck(const SequenceNumber32& ackNumber,
bool scoreboardUpdated,
uint32_t currentDelivered,
const SequenceNumber32& oldHeadSequence)
const SequenceNumber32& oldHeadSequence,
bool receivedData)
{
NS_LOG_FUNCTION(this << ackNumber << scoreboardUpdated << currentDelivered << oldHeadSequence);
// RFC 6675, Section 5, 2nd paragraph:
@@ -1992,10 +1995,14 @@ TcpSocketBase::ProcessAck(const SequenceNumber32& ackNumber,
* (a) the ACK is carrying a SACK block that identifies previously
* unacknowledged and un-SACKed octets between HighACK (TCP.UNA) and
* HighData (m_highTxMark)
*
* The check below implements conditions a), b), and d), and c) is prevented by virtue of not
* reaching this code if SYN or FIN is set, and e) is not supported.
*/
bool isDupack = m_sackEnabled ? scoreboardUpdated
: ackNumber == oldHeadSequence && ackNumber < m_tcb->m_highTxMark;
: (ackNumber == oldHeadSequence &&
ackNumber < m_tcb->m_highTxMark && !receivedData);
NS_LOG_DEBUG("ACK of " << ackNumber << " SND.UNA=" << oldHeadSequence
<< " SND.NXT=" << m_tcb->m_nextTxSequence

4
src/internet/model/tcp-socket-base.h
View File

@@ -1084,11 +1084,13 @@ class TcpSocketBase : public TcpSocket
* \param oldHeadSequence value of HeadSequence before ack
* updated with SACK information
* \param currentDelivered The number of bytes (S)ACKed
* \param receivedData if true indicates that data is piggybacked with ACK
*/
virtual void ProcessAck(const SequenceNumber32& ackNumber,
bool scoreboardUpdated,
uint32_t currentDelivered,
const SequenceNumber32& oldHeadSequence);
const SequenceNumber32& oldHeadSequence,
bool receivedData);
/**
* \brief Recv of a data, put into buffer, call L7 to get it if necessary