Revert "tcp: rfc 2018: implemented SACK option"

This reverts commit 5c31f5a67a.

src/add-ons/kernel/network/protocols/tcp/BufferQueue.cpp

@@ -436,41 +436,6 @@ 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_BUFFER_QUEUE
 
 /*!	Perform a sanity check of the whole queue.

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

@@ -42,7 +42,6 @@ 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;

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

@@ -318,8 +318,7 @@ enum {
 	FLAG_CLOSED					= 0x08,
 	FLAG_DELETE_ON_CLOSE		= 0x10,
 	FLAG_LOCAL					= 0x20,
-	FLAG_RECOVERY				= 0x40,
+	FLAG_RECOVERY				= 0x40
-	FLAG_OPTION_SACK_PERMITTED	= 0x80,
 };
 
 
@@ -449,7 +448,7 @@ TCPEndpoint::TCPEndpoint(net_socket* socket)
 	fCongestionWindow(0),
 	fSlowStartThreshold(0),
 	fState(CLOSED),
-	fFlags(FLAG_OPTION_WINDOW_SCALE | FLAG_OPTION_TIMESTAMP | FLAG_OPTION_SACK_PERMITTED)
+	fFlags(FLAG_OPTION_WINDOW_SCALE | FLAG_OPTION_TIMESTAMP)
 {
 	// TODO: to be replaced with a real read/write locking strategy!
 	mutex_init(&fLock, "tcp lock");
@@ -1425,9 +1424,6 @@ 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;
 	}
 
 	fCongestionWindow = 2 * fSendMaxSegmentSize;
@@ -2019,18 +2015,6 @@ 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
@@ -2039,8 +2023,6 @@ 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;
 		}
 	}
 

src/add-ons/kernel/network/protocols/tcp/tcp.cpp

@@ -140,10 +140,10 @@ add_options(tcp_segment_header &segment, uint8 *buffer, size_t bufferSize)
 		bump_option(option, length);
 	}
 
-	if (segment.sackCount > 0) {
+	if (segment.sack_count > 0) {
 		int sackCount = ((int)(bufferSize - length) - 4) / sizeof(tcp_sack);
-		if (sackCount > segment.sackCount)
+		if (sackCount > segment.sack_count)
-			sackCount = segment.sackCount;
+			sackCount = segment.sack_count;
 
 		if (sackCount > 0) {
 			option->kind = TCP_OPTION_NOP;
@@ -154,7 +154,6 @@ 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);
 		}
 	}
 
@@ -219,18 +218,6 @@ 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) {
@@ -445,9 +432,9 @@ tcp_options_length(tcp_segment_header& segment)
 	if (segment.options & TCP_SACK_PERMITTED)
 		length += 2;
 
-	if (segment.sackCount > 0) {
+	if (segment.sack_count > 0) {
 		int sackCount = min_c((int)((kMaxOptionSize - length - 4)
-			/ sizeof(tcp_sack)), segment.sackCount);
+			/ sizeof(tcp_sack)), segment.sack_count);
 		if (sackCount > 0)
 			length += 4 + sackCount * sizeof(tcp_sack);
 	}

src/add-ons/kernel/network/protocols/tcp/tcp.h

@@ -229,7 +229,6 @@ 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 {
@@ -238,7 +237,7 @@ struct tcp_segment_header {
 		flags(_flags),
 		window_shift(0),
 		max_segment_size(0),
-		sackCount(0),
+		sack_count(0),
 		options(0)
 	{}
 
@@ -254,7 +253,7 @@ struct tcp_segment_header {
 	uint32	timestamp_reply;
 
 	tcp_sack	*sacks;
-	int			sackCount;
+	int			sack_count;
 
 	uint32	options;