Use different neighbor tables per network endpoint

This stores each protocol's neighbor state separately.

This change also removes the need for each neighbor entry to keep
track of their own link address resolver now that all the entries
in a cache will use the same resolver.

PiperOrigin-RevId: 354818155

1 files changed, 12 insertions, 11 deletions

diff --git a/pkg/tcpip/stack/neighbor_cache.go b/pkg/tcpip/stack/neighbor_cache.go
index 64b8046f5..7e3132058 100644
--- a/pkg/tcpip/stack/neighbor_cache.go
+++ b/pkg/tcpip/stack/neighbor_cache.go
@@ -43,8 +43,9 @@ type NeighborStats struct {
 //     Their state is always Static. The amount of static entries stored in the
 //     cache is unbounded.
 type neighborCache struct {
-	nic   *NIC
-	state *NUDState
+	nic     *NIC
+	state   *NUDState
+	linkRes LinkAddressResolver
 
 	// mu protects the fields below.
 	mu sync.RWMutex
@@ -69,7 +70,7 @@ type neighborCache struct {
 // reset to state incomplete, and returned. If no matching entry exists and the
 // cache is not full, a new entry with state incomplete is allocated and
 // returned.
-func (n *neighborCache) getOrCreateEntry(remoteAddr tcpip.Address, linkRes LinkAddressResolver) *neighborEntry {
+func (n *neighborCache) getOrCreateEntry(remoteAddr tcpip.Address) *neighborEntry {
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
@@ -85,7 +86,7 @@ func (n *neighborCache) getOrCreateEntry(remoteAddr tcpip.Address, linkRes LinkA
 
 	// The entry that needs to be created must be dynamic since all static
 	// entries are directly added to the cache via addStaticEntry.
-	entry := newNeighborEntry(n.nic, remoteAddr, n.state, linkRes)
+	entry := newNeighborEntry(n, remoteAddr, n.state)
 	if n.dynamic.count == neighborCacheSize {
 		e := n.dynamic.lru.Back()
 		e.mu.Lock()
@@ -122,8 +123,8 @@ func (n *neighborCache) getOrCreateEntry(remoteAddr tcpip.Address, linkRes LinkA
 // packet prompting NUD/link address resolution.
 //
 // TODO(gvisor.dev/issue/5151): Don't return the neighbor entry.
-func (n *neighborCache) entry(remoteAddr, localAddr tcpip.Address, linkRes LinkAddressResolver, onResolve func(LinkResolutionResult)) (NeighborEntry, <-chan struct{}, tcpip.Error) {
-	entry := n.getOrCreateEntry(remoteAddr, linkRes)
+func (n *neighborCache) entry(remoteAddr, localAddr tcpip.Address, onResolve func(LinkResolutionResult)) (NeighborEntry, <-chan struct{}, tcpip.Error) {
+	entry := n.getOrCreateEntry(remoteAddr)
 	entry.mu.Lock()
 	defer entry.mu.Unlock()
 
@@ -202,7 +203,7 @@ func (n *neighborCache) addStaticEntry(addr tcpip.Address, linkAddr tcpip.LinkAd
 		entry.mu.Unlock()
 	}
 
-	n.cache[addr] = newStaticNeighborEntry(n.nic, addr, linkAddr, n.state)
+	n.cache[addr] = newStaticNeighborEntry(n, addr, linkAddr, n.state)
 }
 
 // removeEntry removes a dynamic or static entry by address from the neighbor
@@ -265,8 +266,8 @@ func (n *neighborCache) neighbors() ([]NeighborEntry, tcpip.Error) {
 	return n.entries(), nil
 }
 
-func (n *neighborCache) get(addr tcpip.Address, linkRes LinkAddressResolver, localAddr tcpip.Address, onResolve func(LinkResolutionResult)) (tcpip.LinkAddress, <-chan struct{}, tcpip.Error) {
-	entry, ch, err := n.entry(addr, localAddr, linkRes, onResolve)
+func (n *neighborCache) get(addr, localAddr tcpip.Address, onResolve func(LinkResolutionResult)) (tcpip.LinkAddress, <-chan struct{}, tcpip.Error) {
+	entry, ch, err := n.entry(addr, localAddr, onResolve)
 	return entry.LinkAddr, ch, err
 }
 
@@ -286,8 +287,8 @@ func (n *neighborCache) removeAll() tcpip.Error {
 // handleProbe handles a neighbor probe as defined by RFC 4861 section 7.2.3.
 //
 // Validation of the probe is expected to be handled by the caller.
-func (n *neighborCache) handleProbe(remoteAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, linkRes LinkAddressResolver) {
-	entry := n.getOrCreateEntry(remoteAddr, linkRes)
+func (n *neighborCache) handleProbe(remoteAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress) {
+	entry := n.getOrCreateEntry(remoteAddr)
 	entry.mu.Lock()
 	entry.handleProbeLocked(remoteLinkAddr)
 	entry.mu.Unlock()