From ebd7c1b889e5d212f4a694d3addbada241936e8e Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Tue, 16 Mar 2021 10:28:04 -0700
Subject: Do not call into Stack from LinkAddressRequest

Calling into the stack from LinkAddressRequest is not needed as we
already have a reference to the network endpoint (IPv6) or network
interface (IPv4/ARP).

PiperOrigin-RevId: 363213973
---
 pkg/tcpip/network/arp/arp.go        | 8 +++-----
 pkg/tcpip/network/ip_test.go        | 4 ++++
 pkg/tcpip/network/ipv6/icmp.go      | 5 ++++-
 pkg/tcpip/network/ipv6/icmp_test.go | 4 ++++
 4 files changed, 15 insertions(+), 6 deletions(-)

(limited to 'pkg/tcpip/network')

diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go
index ae0461a6d..43a4b7cac 100644
--- a/pkg/tcpip/network/arp/arp.go
+++ b/pkg/tcpip/network/arp/arp.go
@@ -305,8 +305,6 @@ func (*endpoint) LinkAddressProtocol() tcpip.NetworkProtocolNumber {
 
 // LinkAddressRequest implements stack.LinkAddressResolver.LinkAddressRequest.
 func (e *endpoint) LinkAddressRequest(targetAddr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress) tcpip.Error {
-	nicID := e.nic.ID()
-
 	stats := e.stats.arp
 
 	if len(remoteLinkAddr) == 0 {
@@ -314,9 +312,9 @@ func (e *endpoint) LinkAddressRequest(targetAddr, localAddr tcpip.Address, remot
 	}
 
 	if len(localAddr) == 0 {
-		addr, ok := e.protocol.stack.GetMainNICAddress(nicID, header.IPv4ProtocolNumber)
-		if !ok {
-			return &tcpip.ErrUnknownNICID{}
+		addr, err := e.nic.PrimaryAddress(header.IPv4ProtocolNumber)
+		if err != nil {
+			return err
 		}
 
 		if len(addr.Address) == 0 {
diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go
index aee1652fa..a4edc69c7 100644
--- a/pkg/tcpip/network/ip_test.go
+++ b/pkg/tcpip/network/ip_test.go
@@ -335,6 +335,10 @@ func (*testInterface) HandleNeighborConfirmation(tcpip.NetworkProtocolNumber, tc
 	return nil
 }
 
+func (*testInterface) PrimaryAddress(tcpip.NetworkProtocolNumber) (tcpip.AddressWithPrefix, tcpip.Error) {
+	return tcpip.AddressWithPrefix{}, nil
+}
+
 func (*testInterface) CheckLocalAddress(tcpip.NetworkProtocolNumber, tcpip.Address) bool {
 	return false
 }
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index 6344a3e09..8059e0690 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -899,13 +899,16 @@ func (e *endpoint) LinkAddressRequest(targetAddr, localAddr tcpip.Address, remot
 	}
 
 	if len(localAddr) == 0 {
+		// Find an address that we can use as our source address.
 		addressEndpoint := e.AcquireOutgoingPrimaryAddress(remoteAddr, false /* allowExpired */)
 		if addressEndpoint == nil {
 			return &tcpip.ErrNetworkUnreachable{}
 		}
 
 		localAddr = addressEndpoint.AddressWithPrefix().Address
-	} else if e.protocol.stack.CheckLocalAddress(e.nic.ID(), ProtocolNumber, localAddr) == 0 {
+		addressEndpoint.DecRef()
+	} else if !e.checkLocalAddress(localAddr) {
+		// The provided local address is not assigned to us.
 		return &tcpip.ErrBadLocalAddress{}
 	}
 
diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go
index d4e63710c..47d713f88 100644
--- a/pkg/tcpip/network/ipv6/icmp_test.go
+++ b/pkg/tcpip/network/ipv6/icmp_test.go
@@ -155,6 +155,10 @@ func (t *testInterface) HandleNeighborConfirmation(tcpip.NetworkProtocolNumber,
 	return nil
 }
 
+func (*testInterface) PrimaryAddress(tcpip.NetworkProtocolNumber) (tcpip.AddressWithPrefix, tcpip.Error) {
+	return tcpip.AddressWithPrefix{}, nil
+}
+
 func (*testInterface) CheckLocalAddress(tcpip.NetworkProtocolNumber, tcpip.Address) bool {
 	return false
 }
-- 
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