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

1 files changed, 4 insertions, 8 deletions

diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 035ab33ca..198e59c77 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1498,20 +1498,16 @@ func (s *Stack) CheckLocalAddress(nicID tcpip.NICID, protocol tcpip.NetworkProto
 			return 0
 		}
 
-		addressEndpoint := nic.findEndpoint(protocol, addr, CanBePrimaryEndpoint)
-		if addressEndpoint == nil {
-			return 0
+		if nic.CheckLocalAddress(protocol, addr) {
+			return nic.id
 		}
 
-		addressEndpoint.DecRef()
-
-		return nic.id
+		return 0
 	}
 
 	// Go through all the NICs.
 	for _, nic := range s.nics {
-		if addressEndpoint := nic.findEndpoint(protocol, addr, CanBePrimaryEndpoint); addressEndpoint != nil {
-			addressEndpoint.DecRef()
+		if nic.CheckLocalAddress(protocol, addr) {
 			return nic.id
 		}
 	}