Merge release-20200522.0-75-gf7663660 (automated)

2 files changed, 34 insertions, 9 deletions

diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go
index 1d601c5da..67513ba7f 100644
--- a/pkg/abi/linux/linux_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go
@@ -124,12 +124,12 @@ func (s *Statx) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (s *Statx) Packed() bool {
-    return s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed()
+    return s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
 func (s *Statx) MarshalUnsafe(dst []byte) {
-    if s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() {
+    if s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
         safecopy.CopyIn(dst, unsafe.Pointer(s))
     } else {
         s.MarshalBytes(dst)
@@ -138,7 +138,7 @@ func (s *Statx) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (s *Statx) UnmarshalUnsafe(src []byte) {
-    if s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
+    if s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() {
         safecopy.CopyOut(unsafe.Pointer(s), src)
     } else {
         s.UnmarshalBytes(src)
@@ -148,7 +148,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
+    if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         s.MarshalBytes(buf) // escapes: fallback.
@@ -178,7 +178,7 @@ func (s *Statx) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (s *Statx) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() {
+    if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -204,7 +204,7 @@ func (s *Statx) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (s *Statx) WriteTo(w io.Writer) (int64, error) {
-    if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
+    if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, s.SizeBytes())
         s.MarshalBytes(buf)
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index 3a19c4468..acacb42e4 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -618,6 +618,20 @@ func (s *sender) splitSeg(seg *segment, size int) {
 	nSeg.data.TrimFront(size)
 	nSeg.sequenceNumber.UpdateForward(seqnum.Size(size))
 	s.writeList.InsertAfter(seg, nSeg)
+
+	// The segment being split does not carry PUSH flag because it is
+	// followed by the newly split segment.
+	// RFC1122 section 4.2.2.2: MUST set the PSH bit in the last buffered
+	// segment (i.e., when there is no more queued data to be sent).
+	// Linux removes PSH flag only when the segment is being split over MSS
+	// and retains it when we are splitting the segment over lack of sender
+	// window space.
+	// ref: net/ipv4/tcp_output.c::tcp_write_xmit(), tcp_mss_split_point()
+	// ref: net/ipv4/tcp_output.c::tcp_write_wakeup(), tcp_snd_wnd_test()
+	if seg.data.Size() > s.maxPayloadSize {
+		seg.flags ^= header.TCPFlagPsh
+	}
+
 	seg.data.CapLength(size)
 }
 
@@ -739,7 +753,7 @@ func (s *sender) maybeSendSegment(seg *segment, limit int, end seqnum.Value) (se
 	if !s.isAssignedSequenceNumber(seg) {
 		// Merge segments if allowed.
 		if seg.data.Size() != 0 {
-			available := int(seg.sequenceNumber.Size(end))
+			available := int(s.sndNxt.Size(end))
 			if available > limit {
 				available = limit
 			}
@@ -782,8 +796,11 @@ func (s *sender) maybeSendSegment(seg *segment, limit int, end seqnum.Value) (se
 					//   sent all at once.
 					return false
 				}
-				if atomic.LoadUint32(&s.ep.cork) != 0 {
-					// Hold back the segment until full.
+				// With TCP_CORK, hold back until minimum of the available
+				// send space and MSS.
+				// TODO(gvisor.dev/issue/2833): Drain the held segments after a
+				// timeout.
+				if seg.data.Size() < s.maxPayloadSize && atomic.LoadUint32(&s.ep.cork) != 0 {
 					return false
 				}
 			}
@@ -843,9 +860,17 @@ func (s *sender) maybeSendSegment(seg *segment, limit int, end seqnum.Value) (se
 		if available == 0 {
 			return false
 		}
+
+		// The segment size limit is computed as a function of sender congestion
+		// window and MSS. When sender congestion window is > 1, this limit can
+		// be larger than MSS. Ensure that the currently available send space
+		// is not greater than minimum of this limit and MSS.
 		if available > limit {
 			available = limit
 		}
+		if available > s.maxPayloadSize {
+			available = s.maxPayloadSize
+		}
 
 		if seg.data.Size() > available {
 			s.splitSeg(seg, available)