1 files changed, 70 insertions, 3 deletions
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 38d066cd1..dbd304b7e 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -40,6 +40,9 @@ type NIC struct {
 	endpoints     map[NetworkEndpointID]*referencedNetworkEndpoint
 	addressRanges []tcpip.Subnet
 	mcastJoins    map[NetworkEndpointID]int32
+	// packetEPs is protected by mu, but the contained PacketEndpoint
+	// values are not.
+	packetEPs map[tcpip.NetworkProtocolNumber][]PacketEndpoint
 
 	stats NICStats
 
@@ -78,7 +81,7 @@ const (
 )
 
 func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback bool) *NIC {
-	return &NIC{
+	nic := &NIC{
 		stack:      stack,
 		id:         id,
 		name:       name,
@@ -87,6 +90,7 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback
 		primary:    make(map[tcpip.NetworkProtocolNumber][]*referencedNetworkEndpoint),
 		endpoints:  make(map[NetworkEndpointID]*referencedNetworkEndpoint),
 		mcastJoins: make(map[NetworkEndpointID]int32),
+		packetEPs:  make(map[tcpip.NetworkProtocolNumber][]PacketEndpoint),
 		stats: NICStats{
 			Tx: DirectionStats{
 				Packets: &tcpip.StatCounter{},
@@ -101,6 +105,16 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback
 			dad: make(map[tcpip.Address]dadState),
 		},
 	}
+
+	// Register supported packet endpoint protocols.
+	for _, netProto := range header.Ethertypes {
+		nic.packetEPs[netProto] = []PacketEndpoint{}
+	}
+	for _, netProto := range stack.networkProtocols {
+		nic.packetEPs[netProto.Number()] = []PacketEndpoint{}
+	}
+
+	return nic
 }
 
 // enable enables the NIC. enable will attach the link to its LinkEndpoint and
@@ -631,7 +645,7 @@ func handlePacket(protocol tcpip.NetworkProtocolNumber, dst, src tcpip.Address,
 // Note that the ownership of the slice backing vv is retained by the caller.
 // This rule applies only to the slice itself, not to the items of the slice;
 // the ownership of the items is not retained by the caller.
-func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, _ tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView) {
+func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView, linkHeader buffer.View) {
 	n.stats.Rx.Packets.Increment()
 	n.stats.Rx.Bytes.IncrementBy(uint64(vv.Size()))
 
@@ -641,6 +655,26 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, _ tcpip.LinkAddr
 		return
 	}
 
+	// If no local link layer address is provided, assume it was sent
+	// directly to this NIC.
+	if local == "" {
+		local = n.linkEP.LinkAddress()
+	}
+
+	// Are any packet sockets listening for this network protocol?
+	n.mu.RLock()
+	packetEPs := n.packetEPs[protocol]
+	// Check whether there are packet sockets listening for every protocol.
+	// If we received a packet with protocol EthernetProtocolAll, then the
+	// previous for loop will have handled it.
+	if protocol != header.EthernetProtocolAll {
+		packetEPs = append(packetEPs, n.packetEPs[header.EthernetProtocolAll]...)
+	}
+	n.mu.RUnlock()
+	for _, ep := range packetEPs {
+		ep.HandlePacket(n.id, local, protocol, vv, linkHeader)
+	}
+
 	if netProto.Number() == header.IPv4ProtocolNumber || netProto.Number() == header.IPv6ProtocolNumber {
 		n.stack.stats.IP.PacketsReceived.Increment()
 	}
@@ -700,7 +734,10 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, _ tcpip.LinkAddr
 		return
 	}
 
-	n.stack.stats.IP.InvalidAddressesReceived.Increment()
+	// If a packet socket handled the packet, don't treat it as invalid.
+	if len(packetEPs) == 0 {
+		n.stack.stats.IP.InvalidAddressesReceived.Increment()
+	}
 }
 
 // DeliverTransportPacket delivers the packets to the appropriate transport
@@ -856,6 +893,36 @@ const (
 	temporary
 )
 
+func (n *NIC) registerPacketEndpoint(netProto tcpip.NetworkProtocolNumber, ep PacketEndpoint) *tcpip.Error {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+
+	eps, ok := n.packetEPs[netProto]
+	if !ok {
+		return tcpip.ErrNotSupported
+	}
+	n.packetEPs[netProto] = append(eps, ep)
+
+	return nil
+}
+
+func (n *NIC) unregisterPacketEndpoint(netProto tcpip.NetworkProtocolNumber, ep PacketEndpoint) {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+
+	eps, ok := n.packetEPs[netProto]
+	if !ok {
+		return
+	}
+
+	for i, epOther := range eps {
+		if epOther == ep {
+			n.packetEPs[netProto] = append(eps[:i], eps[i+1:]...)
+			return
+		}
+	}
+}
+
 type referencedNetworkEndpoint struct {
 	ep       NetworkEndpoint
 	nic      *NIC