3 files changed, 25 insertions, 15 deletions
diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go
index 664cc6fa0..5f216ca21 100644
--- a/pkg/tcpip/stack/packet_buffer.go
+++ b/pkg/tcpip/stack/packet_buffer.go
@@ -268,17 +268,6 @@ func (pk *PacketBuffer) Clone() *PacketBuffer {
 	}
 }
 
-// SourceLinkAddress returns the source link address of the packet.
-func (pk *PacketBuffer) SourceLinkAddress() tcpip.LinkAddress {
-	link := pk.LinkHeader().View()
-
-	if link.IsEmpty() {
-		return ""
-	}
-
-	return header.Ethernet(link).SourceAddress()
-}
-
 // Network returns the network header as a header.Network.
 //
 // Network should only be called when NetworkHeader has been set.
diff --git a/pkg/tcpip/stack/pending_packets.go b/pkg/tcpip/stack/pending_packets.go
index 4a3adcf33..bded8814e 100644
--- a/pkg/tcpip/stack/pending_packets.go
+++ b/pkg/tcpip/stack/pending_packets.go
@@ -101,10 +101,12 @@ func (f *packetsPendingLinkResolution) enqueue(ch <-chan struct{}, r *Route, pro
 		}
 
 		for _, p := range packets {
-			if cancelled {
-				p.route.Stats().IP.OutgoingPacketErrors.Increment()
-			} else if p.route.IsResolutionRequired() {
+			if cancelled || p.route.IsResolutionRequired() {
 				p.route.Stats().IP.OutgoingPacketErrors.Increment()
+
+				if linkResolvableEP, ok := p.route.outgoingNIC.getNetworkEndpoint(p.route.NetProto).(LinkResolvableNetworkEndpoint); ok {
+					linkResolvableEP.HandleLinkResolutionFailure(pkt)
+				}
 			} else {
 				p.route.outgoingNIC.writePacket(p.route, nil /* gso */, p.proto, p.pkt)
 			}
diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go
index 4795208b4..924790779 100644
--- a/pkg/tcpip/stack/registration.go
+++ b/pkg/tcpip/stack/registration.go
@@ -55,7 +55,19 @@ type ControlType int
 // The following are the allowed values for ControlType values.
 // TODO(http://gvisor.dev/issue/3210): Support time exceeded messages.
 const (
-	ControlNetworkUnreachable ControlType = iota
+	// ControlAddressUnreachable indicates that an IPv6 packet did not reach its
+	// destination as the destination address was unreachable.
+	//
+	// This maps to the ICMPv6 Destination Ureachable Code 3 error; see
+	// RFC 4443 section 3.1 for more details.
+	ControlAddressUnreachable ControlType = iota
+	ControlNetworkUnreachable
+	// ControlNoRoute indicates that an IPv4 packet did not reach its destination
+	// because the destination host was unreachable.
+	//
+	// This maps to the ICMPv4 Destination Ureachable Code 1 error; see
+	// RFC 791's Destination Unreachable Message section (page 4) for more
+	// details.
 	ControlNoRoute
 	ControlPacketTooBig
 	ControlPortUnreachable
@@ -503,6 +515,13 @@ type NetworkInterface interface {
 	WritePacketToRemote(tcpip.LinkAddress, *GSO, tcpip.NetworkProtocolNumber, *PacketBuffer) *tcpip.Error
 }
 
+// LinkResolvableNetworkEndpoint handles link resolution events.
+type LinkResolvableNetworkEndpoint interface {
+	// HandleLinkResolutionFailure is called when link resolution prevents the
+	// argument from having been sent.
+	HandleLinkResolutionFailure(*PacketBuffer)
+}
+
 // NetworkEndpoint is the interface that needs to be implemented by endpoints
 // of network layer protocols (e.g., ipv4, ipv6).
 type NetworkEndpoint interface {