netstack/fdbased: add generic segmentation offload (GSO) support

The linux packet socket can handle GSO packets, so we can segment packets to
64K instead of the MTU which is usually 1500.

Here are numbers for the nginx-1m test:
runsc:		579330.01 [Kbytes/sec] received
runsc-gso:	1794121.66 [Kbytes/sec] received
runc:		2122139.06 [Kbytes/sec] received

and for tcp_benchmark:

$ tcp_benchmark  --duration 15   --ideal
[  4]  0.0-15.0 sec  86647 MBytes  48456 Mbits/sec

$ tcp_benchmark --client --duration 15   --ideal
[  4]  0.0-15.0 sec  2173 MBytes  1214 Mbits/sec

$ tcp_benchmark --client --duration 15   --ideal --gso 65536
[  4]  0.0-15.0 sec  19357 MBytes  10825 Mbits/sec

PiperOrigin-RevId: 240809103
Change-Id: I2637f104db28b5d4c64e1e766c610162a195775a

2 files changed, 13 insertions, 13 deletions

diff --git a/pkg/tcpip/link/sharedmem/sharedmem.go b/pkg/tcpip/link/sharedmem/sharedmem.go
index 27d7eb3b9..6e6aa5a13 100644
--- a/pkg/tcpip/link/sharedmem/sharedmem.go
+++ b/pkg/tcpip/link/sharedmem/sharedmem.go
@@ -184,7 +184,7 @@ func (e *endpoint) LinkAddress() tcpip.LinkAddress {
 
 // WritePacket writes outbound packets to the file descriptor. If it is not
 // currently writable, the packet is dropped.
-func (e *endpoint) WritePacket(r *stack.Route, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, _ *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error {
 	// Add the ethernet header here.
 	eth := header.Ethernet(hdr.Prepend(header.EthernetMinimumSize))
 	ethHdr := &header.EthernetFields{
diff --git a/pkg/tcpip/link/sharedmem/sharedmem_test.go b/pkg/tcpip/link/sharedmem/sharedmem_test.go
index 4b8061b13..1f44e224c 100644
--- a/pkg/tcpip/link/sharedmem/sharedmem_test.go
+++ b/pkg/tcpip/link/sharedmem/sharedmem_test.go
@@ -272,7 +272,7 @@ func TestSimpleSend(t *testing.T) {
 			randomFill(buf)
 
 			proto := tcpip.NetworkProtocolNumber(rand.Intn(0x10000))
-			if err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), proto); err != nil {
+			if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), proto); err != nil {
 				t.Fatalf("WritePacket failed: %v", err)
 			}
 
@@ -341,7 +341,7 @@ func TestPreserveSrcAddressInSend(t *testing.T) {
 	hdr := buffer.NewPrependable(header.EthernetMinimumSize)
 
 	proto := tcpip.NetworkProtocolNumber(rand.Intn(0x10000))
-	if err := c.ep.WritePacket(&r, hdr, buffer.VectorisedView{}, proto); err != nil {
+	if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buffer.VectorisedView{}, proto); err != nil {
 		t.Fatalf("WritePacket failed: %v", err)
 	}
 
@@ -395,7 +395,7 @@ func TestFillTxQueue(t *testing.T) {
 	for i := queuePipeSize / 40; i > 0; i-- {
 		hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
 
-		if err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
+		if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
 			t.Fatalf("WritePacket failed unexpectedly: %v", err)
 		}
 
@@ -410,7 +410,7 @@ func TestFillTxQueue(t *testing.T) {
 
 	// Next attempt to write must fail.
 	hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-	if want, err := tcpip.ErrWouldBlock, c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != want {
+	if want, err := tcpip.ErrWouldBlock, c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != want {
 		t.Fatalf("WritePacket return unexpected result: got %v, want %v", err, want)
 	}
 }
@@ -435,7 +435,7 @@ func TestFillTxQueueAfterBadCompletion(t *testing.T) {
 	// Send two packets so that the id slice has at least two slots.
 	for i := 2; i > 0; i-- {
 		hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-		if err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
+		if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
 			t.Fatalf("WritePacket failed unexpectedly: %v", err)
 		}
 	}
@@ -455,7 +455,7 @@ func TestFillTxQueueAfterBadCompletion(t *testing.T) {
 	ids := make(map[uint64]struct{})
 	for i := queuePipeSize / 40; i > 0; i-- {
 		hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-		if err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
+		if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
 			t.Fatalf("WritePacket failed unexpectedly: %v", err)
 		}
 
@@ -470,7 +470,7 @@ func TestFillTxQueueAfterBadCompletion(t *testing.T) {
 
 	// Next attempt to write must fail.
 	hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-	if want, err := tcpip.ErrWouldBlock, c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != want {
+	if want, err := tcpip.ErrWouldBlock, c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != want {
 		t.Fatalf("WritePacket return unexpected result: got %v, want %v", err, want)
 	}
 }
@@ -493,7 +493,7 @@ func TestFillTxMemory(t *testing.T) {
 	ids := make(map[uint64]struct{})
 	for i := queueDataSize / bufferSize; i > 0; i-- {
 		hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-		if err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
+		if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
 			t.Fatalf("WritePacket failed unexpectedly: %v", err)
 		}
 
@@ -509,7 +509,7 @@ func TestFillTxMemory(t *testing.T) {
 
 	// Next attempt to write must fail.
 	hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-	err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber)
+	err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber)
 	if want := tcpip.ErrWouldBlock; err != want {
 		t.Fatalf("WritePacket return unexpected result: got %v, want %v", err, want)
 	}
@@ -534,7 +534,7 @@ func TestFillTxMemoryWithMultiBuffer(t *testing.T) {
 	// until there is only one buffer left.
 	for i := queueDataSize/bufferSize - 1; i > 0; i-- {
 		hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-		if err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
+		if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
 			t.Fatalf("WritePacket failed unexpectedly: %v", err)
 		}
 
@@ -547,7 +547,7 @@ func TestFillTxMemoryWithMultiBuffer(t *testing.T) {
 	{
 		hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
 		uu := buffer.NewView(bufferSize).ToVectorisedView()
-		if want, err := tcpip.ErrWouldBlock, c.ep.WritePacket(&r, hdr, uu, header.IPv4ProtocolNumber); err != want {
+		if want, err := tcpip.ErrWouldBlock, c.ep.WritePacket(&r, nil /* gso */, hdr, uu, header.IPv4ProtocolNumber); err != want {
 			t.Fatalf("WritePacket return unexpected result: got %v, want %v", err, want)
 		}
 	}
@@ -555,7 +555,7 @@ func TestFillTxMemoryWithMultiBuffer(t *testing.T) {
 	// Attempt to write the one-buffer packet again. It must succeed.
 	{
 		hdr := buffer.NewPrependable(int(c.ep.MaxHeaderLength()))
-		if err := c.ep.WritePacket(&r, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
+		if err := c.ep.WritePacket(&r, nil /* gso */, hdr, buf.ToVectorisedView(), header.IPv4ProtocolNumber); err != nil {
 			t.Fatalf("WritePacket failed unexpectedly: %v", err)
 		}
 	}