Add support to return protocol in recvmsg for AF_PACKET.

Updates #173

PiperOrigin-RevId: 321690756

1 files changed, 19 insertions, 0 deletions

diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 71bcee785..48ad56d4d 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -549,6 +549,25 @@ type Endpoint interface {
 	SetOwner(owner PacketOwner)
 }
 
+// LinkPacketInfo holds Link layer information for a received packet.
+//
+// +stateify savable
+type LinkPacketInfo struct {
+	// Protocol is the NetworkProtocolNumber for the packet.
+	Protocol NetworkProtocolNumber
+}
+
+// PacketEndpoint are additional methods that are only implemented by Packet
+// endpoints.
+type PacketEndpoint interface {
+	// ReadPacket reads a datagram/packet from the endpoint and optionally
+	// returns the sender and additional LinkPacketInfo.
+	//
+	// This method does not block if there is no data pending. It will also
+	// either return an error or data, never both.
+	ReadPacket(*FullAddress, *LinkPacketInfo) (buffer.View, ControlMessages, *Error)
+}
+
 // EndpointInfo is the interface implemented by each endpoint info struct.
 type EndpointInfo interface {
 	// IsEndpointInfo is an empty method to implement the tcpip.EndpointInfo