Support IP_PKTINFO and IPV6_RECVPKTINFO on raw sockets

Updates #1584, #3556.

PiperOrigin-RevId: 402354066

1 files changed, 30 insertions, 2 deletions

diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 181b478d0..ce76774af 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -49,6 +49,7 @@ type rawPacket struct {
 	receivedAt time.Time             `state:".(int64)"`
 	// senderAddr is the network address of the sender.
 	senderAddr tcpip.FullAddress
+	packetInfo tcpip.IPPacketInfo
 }
 
 // endpoint is the raw socket implementation of tcpip.Endpoint. It is legal to
@@ -208,6 +209,23 @@ func (e *endpoint) Read(dst io.Writer, opts tcpip.ReadOptions) (tcpip.ReadResult
 	if opts.NeedRemoteAddr {
 		res.RemoteAddr = pkt.senderAddr
 	}
+	switch netProto := e.net.NetProto(); netProto {
+	case header.IPv4ProtocolNumber:
+		if e.ops.GetReceivePacketInfo() {
+			res.ControlMessages.HasIPPacketInfo = true
+			res.ControlMessages.PacketInfo = pkt.packetInfo
+		}
+	case header.IPv6ProtocolNumber:
+		if e.ops.GetIPv6ReceivePacketInfo() {
+			res.ControlMessages.HasIPv6PacketInfo = true
+			res.ControlMessages.IPv6PacketInfo = tcpip.IPv6PacketInfo{
+				NIC:  pkt.packetInfo.NIC,
+				Addr: pkt.packetInfo.DestinationAddr,
+			}
+		}
+	default:
+		panic(fmt.Sprintf("unrecognized network protocol = %d", netProto))
+	}
 
 	n, err := pkt.data.ReadTo(dst, opts.Peek)
 	if n == 0 && err != nil {
@@ -435,7 +453,9 @@ func (e *endpoint) HandlePacket(pkt *stack.PacketBuffer) {
 			return false
 		}
 
-		srcAddr := pkt.Network().SourceAddress()
+		net := pkt.Network()
+		dstAddr := net.DestinationAddress()
+		srcAddr := net.SourceAddress()
 		info := e.net.Info()
 
 		switch state := e.net.State(); state {
@@ -457,7 +477,7 @@ func (e *endpoint) HandlePacket(pkt *stack.PacketBuffer) {
 			}
 
 			// If bound to an address, only accept data for that address.
-			if info.BindAddr != "" && info.BindAddr != pkt.Network().DestinationAddress() {
+			if info.BindAddr != "" && info.BindAddr != dstAddr {
 				return false
 			}
 		default:
@@ -472,6 +492,14 @@ func (e *endpoint) HandlePacket(pkt *stack.PacketBuffer) {
 				NIC:  pkt.NICID,
 				Addr: srcAddr,
 			},
+			packetInfo: tcpip.IPPacketInfo{
+				// TODO(gvisor.dev/issue/3556): dstAddr may be a multicast or broadcast
+				// address. LocalAddr should hold a unicast address that can be
+				// used to respond to the incoming packet.
+				LocalAddr:       dstAddr,
+				DestinationAddr: dstAddr,
+				NIC:             pkt.NICID,
+			},
 		}
 
 		// Raw IPv4 endpoints return the IP header, but IPv6 endpoints do not.