Implement SO_REUSEPORT for TCP and UDP sockets

This option allows multiple sockets to be bound to the same port.

Incoming packets are distributed to sockets using a hash based on source and
destination addresses. This means that all packets from one sender will be
received by the same server socket.

PiperOrigin-RevId: 227153413
Change-Id: I59b6edda9c2209d5b8968671e9129adb675920cf

2 files changed, 24 insertions, 1 deletions

diff --git a/pkg/sentry/socket/epsocket/epsocket.go b/pkg/sentry/socket/epsocket/epsocket.go
index 1b9c75949..d65b5f49e 100644
--- a/pkg/sentry/socket/epsocket/epsocket.go
+++ b/pkg/sentry/socket/epsocket/epsocket.go
@@ -634,6 +634,18 @@ func getSockOptSocket(t *kernel.Task, s socket.Socket, ep commonEndpoint, family
 
 		return int32(v), nil
 
+	case linux.SO_REUSEPORT:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		var v tcpip.ReusePortOption
+		if err := ep.GetSockOpt(&v); err != nil {
+			return nil, syserr.TranslateNetstackError(err)
+		}
+
+		return int32(v), nil
+
 	case linux.SO_KEEPALIVE:
 		if outLen < sizeOfInt32 {
 			return nil, syserr.ErrInvalidArgument
@@ -900,6 +912,14 @@ func setSockOptSocket(t *kernel.Task, s socket.Socket, ep commonEndpoint, name i
 		v := usermem.ByteOrder.Uint32(optVal)
 		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.ReuseAddressOption(v)))
 
+	case linux.SO_REUSEPORT:
+		if len(optVal) < sizeOfInt32 {
+			return syserr.ErrInvalidArgument
+		}
+
+		v := usermem.ByteOrder.Uint32(optVal)
+		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.ReusePortOption(v)))
+
 	case linux.SO_PASSCRED:
 		if len(optVal) < sizeOfInt32 {
 			return syserr.ErrInvalidArgument
diff --git a/pkg/sentry/socket/rpcinet/socket.go b/pkg/sentry/socket/rpcinet/socket.go
index 257bc2d71..8c8ebadb7 100644
--- a/pkg/sentry/socket/rpcinet/socket.go
+++ b/pkg/sentry/socket/rpcinet/socket.go
@@ -285,7 +285,10 @@ func (s *socketOperations) Accept(t *kernel.Task, peerRequested bool, flags int,
 	if blocking && se == syserr.ErrTryAgain {
 		// Register for notifications.
 		e, ch := waiter.NewChannelEntry(nil)
-		s.EventRegister(&e, waiter.EventIn)
+		// FIXME: This waiter.EventHUp is a partial
+		// measure, need to figure out how to translate linux events to
+		// internal events.
+		s.EventRegister(&e, waiter.EventIn|waiter.EventHUp)
 		defer s.EventUnregister(&e)
 
 		// Try to accept the connection again; if it fails, then wait until we