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tcp: rfc 2018: implemented SACK option

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Change-Id: I269ad2682446c4d37bae21dcf9f3036de964ff2c
Reviewed-on: https://review.haiku-os.org/c/haiku/+/53
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
This commit is contained in:
A-star-ayush 2017-08-25 14:14:35 +05:30 committed by Jérôme Duval
parent a6e1e7e941
commit 745830a01b
5 changed files with 78 additions and 9 deletions
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36
src/add-ons/kernel/network/protocols/tcp/BufferQueue.cpp
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@ -10,6 +10,7 @@
#include "BufferQueue.h"
#include <KernelExport.h>
#include <arpa/inet.h>
//#define TRACE_BUFFER_QUEUE
@ -436,6 +437,41 @@ BufferQueue::SetPushPointer()
fPushPointer = fList.Tail()->sequence + fList.Tail()->size;
}
int
BufferQueue::PopulateSackInfo(tcp_sequence sequence, int maxSackCount, tcp_sack* sacks)
{
SegmentList::ReverseIterator iterator = fList.GetReverseIterator();
net_buffer* buffer = iterator.Next();
int sackCount = 0;
while (buffer != NULL && buffer->sequence > sequence) {
if (buffer->sequence + buffer->size < sacks[sackCount].left_edge) {
if (sackCount + 1 == maxSackCount)
break;
++sackCount;
sacks[sackCount].left_edge = buffer->sequence;
sacks[sackCount].right_edge = buffer->sequence + buffer->size;
} else {
sacks[sackCount].left_edge = buffer->sequence;
if (sacks[sackCount].right_edge == 0)
sacks[sackCount].right_edge = buffer->sequence + buffer->size;
}
buffer = iterator.Next();
}
if (sacks[0].left_edge != 0) {
for (int i = 0; i <= sackCount; ++i) {
sacks[i].left_edge = htonl(sacks[i].left_edge);
sacks[i].right_edge = htonl(sacks[i].right_edge);
}
++sackCount;
}
return sackCount;
}
#if DEBUG_TCP_BUFFER_QUEUE
/*! Perform a sanity check of the whole queue.

1
src/add-ons/kernel/network/protocols/tcp/BufferQueue.h
View File

@ -38,6 +38,7 @@ public:
inline size_t PushedData() const;
void SetPushPointer();
int PopulateSackInfo(tcp_sequence sequence, int maxSackCount, tcp_sack* sacks);
size_t Used() const { return fNumBytes; }
inline size_t Free() const;

22
src/add-ons/kernel/network/protocols/tcp/TCPEndpoint.cpp
View File

@ -319,7 +319,8 @@ enum {
FLAG_CLOSED = 0x08,
FLAG_DELETE_ON_CLOSE = 0x10,
FLAG_LOCAL = 0x20,
FLAG_RECOVERY = 0x40
FLAG_RECOVERY = 0x40,
FLAG_OPTION_SACK_PERMITTED = 0x80,
};
@ -451,7 +452,7 @@ TCPEndpoint::TCPEndpoint(net_socket* socket)
fCongestionWindow(0),
fSlowStartThreshold(0),
fState(CLOSED),
fFlags(FLAG_OPTION_WINDOW_SCALE | FLAG_OPTION_TIMESTAMP)
fFlags(FLAG_OPTION_WINDOW_SCALE | FLAG_OPTION_TIMESTAMP | FLAG_OPTION_SACK_PERMITTED)
{
// TODO: to be replaced with a real read/write locking strategy!
mutex_init(&fLock, "tcp lock");
@ -1413,6 +1414,9 @@ TCPEndpoint::_PrepareReceivePath(tcp_segment_header& segment)
fReceivedTimestamp = segment.timestamp_value;
} else
fFlags &= ~FLAG_OPTION_TIMESTAMP;
if ((segment.options & TCP_SACK_PERMITTED) == 0)
fFlags &= ~FLAG_OPTION_SACK_PERMITTED;
}
if (fSendMaxSegmentSize > 2190)
@ -2019,6 +2023,18 @@ TCPEndpoint::_SendQueued(bool force, uint32 sendWindow)
segment.timestamp_value = tcp_now();
}
// SACK information is embedded with duplicate acknowledgements
if (!fReceiveQueue.IsContiguous() && fLastAcknowledgeSent == fReceiveNext
&& (fFlags & FLAG_OPTION_SACK_PERMITTED) != 0) {
segment.options |= TCP_HAS_SACK;
int maxSackCount = 4 - ((fFlags & FLAG_OPTION_TIMESTAMP) != 0);
segment.sacks = (tcp_sack*)calloc(maxSackCount, sizeof(tcp_sack));
if (segment.sacks != NULL)
segment.sackCount = fReceiveQueue.PopulateSackInfo(fReceiveNext, maxSackCount, segment.sacks);
else
segment.sackCount = 0;
}
if ((segment.flags & TCP_FLAG_SYNCHRONIZE) != 0
&& fSendNext == fInitialSendSequence) {
// add connection establishment options
@ -2027,6 +2043,8 @@ TCPEndpoint::_SendQueued(bool force, uint32 sendWindow)
segment.options |= TCP_HAS_WINDOW_SCALE;
segment.window_shift = fReceiveWindowShift;
}
if ((fFlags & FLAG_OPTION_SACK_PERMITTED) != 0)
segment.options |= TCP_SACK_PERMITTED;
}
}

23
src/add-ons/kernel/network/protocols/tcp/tcp.cpp
View File

@ -139,10 +139,10 @@ add_options(tcp_segment_header &segment, uint8 *buffer, size_t bufferSize)
bump_option(option, length);
}
if (segment.sack_count > 0) {
if (segment.sackCount > 0) {
int sackCount = ((int)(bufferSize - length) - 4) / sizeof(tcp_sack);
if (sackCount > segment.sack_count)
sackCount = segment.sack_count;
if (sackCount > segment.sackCount)
sackCount = segment.sackCount;
if (sackCount > 0) {
option->kind = TCP_OPTION_NOP;
@ -153,6 +153,7 @@ add_options(tcp_segment_header &segment, uint8 *buffer, size_t bufferSize)
option->length = 2 + sackCount * sizeof(tcp_sack);
memcpy(option->sack, segment.sacks, sackCount * sizeof(tcp_sack));
bump_option(option, length);
free(segment.sacks);
}
}
@ -217,6 +218,18 @@ process_options(tcp_segment_header &segment, net_buffer *buffer, size_t size)
if (option->length == 2 && size >= 2)
segment.options |= TCP_SACK_PERMITTED;
break;
case TCP_OPTION_SACK:
if (size >= option->length) {
segment.options |= TCP_HAS_SACK;
segment.sackCount = (option->length - 2) / sizeof(tcp_sack);
segment.sacks = option->sack;
for(int i = 0; i < segment.sackCount; ++i) {
segment.sacks[i].left_edge = ntohl(segment.sacks[i].left_edge);
segment.sacks[i].right_edge = ntohl(segment.sacks[i].right_edge);
}
}
break;
}
if (length < 0) {
@ -431,9 +444,9 @@ tcp_options_length(tcp_segment_header& segment)
if (segment.options & TCP_SACK_PERMITTED)
length += 2;
if (segment.sack_count > 0) {
if (segment.sackCount > 0) {
int sackCount = min_c((int)((kMaxOptionSize - length - 4)
/ sizeof(tcp_sack)), segment.sack_count);
/ sizeof(tcp_sack)), segment.sackCount);
if (sackCount > 0)
length += 4 + sackCount * sizeof(tcp_sack);
}

5
src/add-ons/kernel/network/protocols/tcp/tcp.h
View File

@ -231,6 +231,7 @@ enum {
TCP_HAS_WINDOW_SCALE = 1 << 0,
TCP_HAS_TIMESTAMPS = 1 << 1,
TCP_SACK_PERMITTED = 1 << 2,
TCP_HAS_SACK = 1 << 3,
};
struct tcp_segment_header {
@ -239,7 +240,7 @@ struct tcp_segment_header {
flags(_flags),
window_shift(0),
max_segment_size(0),
sack_count(0),
sackCount(0),
options(0)
{}
@ -255,7 +256,7 @@ struct tcp_segment_header {
uint32 timestamp_reply;
tcp_sack *sacks;
int sack_count;
int sackCount;
uint32 options;