From f0b3298db07df63fa74559d5689008f9de9980a9 Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Mon, 3 May 2021 16:38:51 -0700
Subject: Convey GSO capabilities through GSOEndpoint

...as all GSO capable endpoints must implement GSOEndpoint.

PiperOrigin-RevId: 371804175
---
 pkg/tcpip/link/fdbased/endpoint.go           | 21 ++++++++++++++++-----
 pkg/tcpip/link/fdbased/packet_dispatchers.go |  4 ++--
 2 files changed, 18 insertions(+), 7 deletions(-)

(limited to 'pkg/tcpip/link/fdbased')

diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index 6fe2dd33c..bddb1d0a2 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -97,6 +97,9 @@ func (p PacketDispatchMode) String() string {
 	}
 }
 
+var _ stack.LinkEndpoint = (*endpoint)(nil)
+var _ stack.GSOEndpoint = (*endpoint)(nil)
+
 type endpoint struct {
 	// fds is the set of file descriptors each identifying one inbound/outbound
 	// channel. The endpoint will dispatch from all inbound channels as well as
@@ -133,6 +136,9 @@ type endpoint struct {
 
 	// wg keeps track of running goroutines.
 	wg sync.WaitGroup
+
+	// gsoKind is the supported kind of GSO.
+	gsoKind stack.SupportedGSO
 }
 
 // Options specify the details about the fd-based endpoint to be created.
@@ -254,9 +260,9 @@ func New(opts *Options) (stack.LinkEndpoint, error) {
 		if isSocket {
 			if opts.GSOMaxSize != 0 {
 				if opts.SoftwareGSOEnabled {
-					e.caps |= stack.CapabilitySoftwareGSO
+					e.gsoKind = stack.SWGSOSupported
 				} else {
-					e.caps |= stack.CapabilityHardwareGSO
+					e.gsoKind = stack.HWGSOSupported
 				}
 				e.gsoMaxSize = opts.GSOMaxSize
 			}
@@ -469,7 +475,7 @@ func (e *endpoint) WritePacket(r stack.RouteInfo, protocol tcpip.NetworkProtocol
 	var builder iovec.Builder
 
 	fd := e.fds[pkt.Hash%uint32(len(e.fds))]
-	if e.Capabilities()&stack.CapabilityHardwareGSO != 0 {
+	if e.gsoKind == stack.HWGSOSupported {
 		vnetHdr := virtioNetHdr{}
 		if pkt.GSOOptions.Type != stack.GSONone {
 			vnetHdr.hdrLen = uint16(pkt.HeaderSize())
@@ -510,7 +516,7 @@ func (e *endpoint) sendBatch(batchFD int, batch []*stack.PacketBuffer) (int, tcp
 		}
 
 		var vnetHdrBuf []byte
-		if e.Capabilities()&stack.CapabilityHardwareGSO != 0 {
+		if e.gsoKind == stack.HWGSOSupported {
 			vnetHdr := virtioNetHdr{}
 			if pkt.GSOOptions.Type != stack.GSONone {
 				vnetHdr.hdrLen = uint16(pkt.HeaderSize())
@@ -630,11 +636,16 @@ func (e *endpoint) dispatchLoop(inboundDispatcher linkDispatcher) tcpip.Error {
 	}
 }
 
-// GSOMaxSize returns the maximum GSO packet size.
+// GSOMaxSize implements stack.GSOEndpoint.
 func (e *endpoint) GSOMaxSize() uint32 {
 	return e.gsoMaxSize
 }
 
+// SupportsHWGSO implements stack.GSOEndpoint.
+func (e *endpoint) SupportedGSO() stack.SupportedGSO {
+	return e.gsoKind
+}
+
 // ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
 func (e *endpoint) ARPHardwareType() header.ARPHardwareType {
 	if e.hdrSize > 0 {
diff --git a/pkg/tcpip/link/fdbased/packet_dispatchers.go b/pkg/tcpip/link/fdbased/packet_dispatchers.go
index a7adf822b..4b7ef3aac 100644
--- a/pkg/tcpip/link/fdbased/packet_dispatchers.go
+++ b/pkg/tcpip/link/fdbased/packet_dispatchers.go
@@ -128,7 +128,7 @@ type readVDispatcher struct {
 
 func newReadVDispatcher(fd int, e *endpoint) (linkDispatcher, error) {
 	d := &readVDispatcher{fd: fd, e: e}
-	skipsVnetHdr := d.e.Capabilities()&stack.CapabilityHardwareGSO != 0
+	skipsVnetHdr := d.e.gsoKind == stack.HWGSOSupported
 	d.buf = newIovecBuffer(BufConfig, skipsVnetHdr)
 	return d, nil
 }
@@ -212,7 +212,7 @@ func newRecvMMsgDispatcher(fd int, e *endpoint) (linkDispatcher, error) {
 		bufs:    make([]*iovecBuffer, MaxMsgsPerRecv),
 		msgHdrs: make([]rawfile.MMsgHdr, MaxMsgsPerRecv),
 	}
-	skipsVnetHdr := d.e.Capabilities()&stack.CapabilityHardwareGSO != 0
+	skipsVnetHdr := d.e.gsoKind == stack.HWGSOSupported
 	for i := range d.bufs {
 		d.bufs[i] = newIovecBuffer(BufConfig, skipsVnetHdr)
 	}
-- 
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