Check local address directly through NIC

Network endpoints that wish to check addresses on another NIC-local
network endpoint may now do so through the NetworkInterface.

This fixes a lock ordering issue between NIC removal and link
resolution. Before this change:

  NIC Removal takes the stack lock, neighbor cache lock then neighbor
  entries' locks.

  When performing IPv4 link resolution, we take the entry lock then ARP
  would try check IPv4 local addresses through the stack which tries to
  obtain the stack's lock.

Now that ARP can check IPv4 addreses through the NIC, we avoid the lock
ordering issue, while also removing the need for stack to lookup the
NIC.

PiperOrigin-RevId: 356034245

2 files changed, 24 insertions, 4 deletions

diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index dcfd93bab..edf4ef4e5 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -148,6 +148,18 @@ func (*icmpv6PacketTooBigSockError) Kind() stack.TransportErrorKind {
 	return stack.PacketTooBigTransportError
 }
 
+func (e *endpoint) checkLocalAddress(addr tcpip.Address) bool {
+	if e.nic.Spoofing() {
+		return true
+	}
+
+	if addressEndpoint := e.AcquireAssignedAddress(addr, false, stack.NeverPrimaryEndpoint); addressEndpoint != nil {
+		addressEndpoint.DecRef()
+		return true
+	}
+	return false
+}
+
 // handleControl handles the case when an ICMP packet contains the headers of
 // the original packet that caused the ICMP one to be sent. This information is
 // used to find out which transport endpoint must be notified about the ICMP
@@ -165,8 +177,8 @@ func (e *endpoint) handleControl(transErr stack.TransportError, pkt *stack.Packe
 	//
 	// Drop packet if it doesn't have the basic IPv6 header or if the
 	// original source address doesn't match an address we own.
-	src := hdr.SourceAddress()
-	if e.protocol.stack.CheckLocalAddress(e.nic.ID(), ProtocolNumber, src) == 0 {
+	srcAddr := hdr.SourceAddress()
+	if !e.checkLocalAddress(srcAddr) {
 		return
 	}
 
@@ -192,7 +204,7 @@ func (e *endpoint) handleControl(transErr stack.TransportError, pkt *stack.Packe
 		p = fragHdr.TransportProtocol()
 	}
 
-	e.dispatcher.DeliverTransportError(src, hdr.DestinationAddress(), ProtocolNumber, p, transErr, pkt)
+	e.dispatcher.DeliverTransportError(srcAddr, hdr.DestinationAddress(), ProtocolNumber, p, transErr, pkt)
 }
 
 // getLinkAddrOption searches NDP options for a given link address option using
@@ -377,7 +389,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer, hasFragmentHeader bool) {
 		// section 5.4.3.
 
 		// Is the NS targeting us?
-		if e.protocol.stack.CheckLocalAddress(e.nic.ID(), ProtocolNumber, targetAddr) == 0 {
+		if !e.checkLocalAddress(targetAddr) {
 			return
 		}
 
diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go
index ca46ec61f..4dbfb80da 100644
--- a/pkg/tcpip/network/ipv6/icmp_test.go
+++ b/pkg/tcpip/network/ipv6/icmp_test.go
@@ -124,6 +124,10 @@ func (*testInterface) Promiscuous() bool {
 	return false
 }
 
+func (*testInterface) Spoofing() bool {
+	return false
+}
+
 func (t *testInterface) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) tcpip.Error {
 	return t.LinkEndpoint.WritePacket(r.Fields(), gso, protocol, pkt)
 }
@@ -149,6 +153,10 @@ func (t *testInterface) HandleNeighborConfirmation(tcpip.NetworkProtocolNumber,
 	return nil
 }
 
+func (*testInterface) CheckLocalAddress(tcpip.NetworkProtocolNumber, tcpip.Address) bool {
+	return false
+}
+
 func handleICMPInIPv6(ep stack.NetworkEndpoint, src, dst tcpip.Address, icmp header.ICMPv6) {
 	ip := buffer.NewView(header.IPv6MinimumSize)
 	header.IPv6(ip).Encode(&header.IPv6Fields{