Merge release-20210208.0-107-g6bc27946a (automated)

pkg/tcpip/stack/neighbor_cache.go

@@ -140,7 +140,7 @@ func (n *neighborCache) entry(remoteAddr, localAddr tcpip.Address, onResolve fun
 		//   a node continues sending packets to that neighbor using the cached
 		//   link-layer address."
 		if onResolve != nil {
-			onResolve(LinkResolutionResult{LinkAddress: entry.mu.neigh.LinkAddr, Success: true})
+			onResolve(LinkResolutionResult{LinkAddress: entry.mu.neigh.LinkAddr, Err: nil})
 		}
 		return entry.mu.neigh, nil, nil
 	case Unknown, Incomplete, Unreachable:

pkg/tcpip/stack/neighbor_entry.go

@@ -157,8 +157,8 @@ func newStaticNeighborEntry(cache *neighborCache, addr tcpip.Address, linkAddr t
 // the link address if resolution completed successfully.
 //
 // Precondition: e.mu MUST be locked.
-func (e *neighborEntry) notifyCompletionLocked(succeeded bool) {
-	res := LinkResolutionResult{LinkAddress: e.mu.neigh.LinkAddr, Success: succeeded}
+func (e *neighborEntry) notifyCompletionLocked(err tcpip.Error) {
+	res := LinkResolutionResult{LinkAddress: e.mu.neigh.LinkAddr, Err: err}
 	for _, callback := range e.mu.onResolve {
 		callback(res)
 	}
@@ -173,7 +173,7 @@ func (e *neighborEntry) notifyCompletionLocked(succeeded bool) {
 		// is resolved (which ends up obtaining the entry's lock) while holding the
 		// link resolution queue's lock. Dequeuing packets in a new goroutine avoids
 		// a lock ordering violation.
-		go e.cache.nic.linkResQueue.dequeue(ch, e.mu.neigh.LinkAddr, succeeded)
+		go e.cache.nic.linkResQueue.dequeue(ch, e.mu.neigh.LinkAddr, err)
 	}
 }
 
@@ -227,7 +227,13 @@ func (e *neighborEntry) removeLocked() {
 	e.mu.neigh.UpdatedAtNanos = e.cache.nic.stack.clock.NowNanoseconds()
 	e.dispatchRemoveEventLocked()
 	e.cancelTimerLocked()
-	e.notifyCompletionLocked(false /* succeeded */)
+	// TODO(https://gvisor.dev/issues/5583): test the case where this function is
+	// called during resolution; that can happen in at least these scenarios:
+	//
+	// - manual address removal during resolution
+	//
+	// - neighbor cache eviction during resolution
+	e.notifyCompletionLocked(&tcpip.ErrAborted{})
 }
 
 // setStateLocked transitions the entry to the specified state immediately.
@@ -302,9 +308,8 @@ func (e *neighborEntry) setStateLocked(next NeighborState) {
 		e.mu.timer = timer{
 			done: &done,
 			timer: e.cache.nic.stack.Clock().AfterFunc(0, func() {
-				var err tcpip.Error
-				timedoutResolution := remaining == 0
-				if !timedoutResolution {
+				var err tcpip.Error = &tcpip.ErrTimeout{}
+				if remaining != 0 {
 					err = e.cache.linkRes.LinkAddressRequest(addr, "" /* localAddr */, linkAddr)
 				}
 
@@ -316,8 +321,9 @@ func (e *neighborEntry) setStateLocked(next NeighborState) {
 					return
 				}
 
-				if timedoutResolution || err != nil {
+				if err != nil {
 					e.setStateLocked(Unreachable)
+					e.notifyCompletionLocked(err)
 					e.dispatchChangeEventLocked()
 					return
 				}
@@ -328,7 +334,6 @@ func (e *neighborEntry) setStateLocked(next NeighborState) {
 		}
 
 	case Unreachable:
-		e.notifyCompletionLocked(false /* succeeded */)
 
 	case Unknown, Stale, Static:
 		// Do nothing
@@ -374,9 +379,8 @@ func (e *neighborEntry) handlePacketQueuedLocked(localAddr tcpip.Address) {
 		e.mu.timer = timer{
 			done: &done,
 			timer: e.cache.nic.stack.Clock().AfterFunc(0, func() {
-				var err tcpip.Error
-				timedoutResolution := remaining == 0
-				if !timedoutResolution {
+				var err tcpip.Error = &tcpip.ErrTimeout{}
+				if remaining != 0 {
 					// As per RFC 4861 section 7.2.2:
 					//
 					//  If the source address of the packet prompting the solicitation is
@@ -395,8 +399,9 @@ func (e *neighborEntry) handlePacketQueuedLocked(localAddr tcpip.Address) {
 					return
 				}
 
-				if timedoutResolution || err != nil {
+				if err != nil {
 					e.setStateLocked(Unreachable)
+					e.notifyCompletionLocked(err)
 					e.dispatchChangeEventLocked()
 					return
 				}
@@ -442,7 +447,7 @@ func (e *neighborEntry) handleProbeLocked(remoteLinkAddr tcpip.LinkAddress) {
 		//  - RFC 4861 section 7.2.3
 		e.mu.neigh.LinkAddr = remoteLinkAddr
 		e.setStateLocked(Stale)
-		e.notifyCompletionLocked(true /* succeeded */)
+		e.notifyCompletionLocked(nil)
 		e.dispatchChangeEventLocked()
 
 	case Reachable, Delay, Probe:
@@ -504,7 +509,7 @@ func (e *neighborEntry) handleConfirmationLocked(linkAddr tcpip.LinkAddress, fla
 		}
 		e.dispatchChangeEventLocked()
 		e.mu.isRouter = flags.IsRouter
-		e.notifyCompletionLocked(true /* succeeded */)
+		e.notifyCompletionLocked(nil)
 
 		// "Note that the Override flag is ignored if the entry is in the
 		// INCOMPLETE state." - RFC 4861 section 7.2.5
@@ -539,7 +544,7 @@ func (e *neighborEntry) handleConfirmationLocked(linkAddr tcpip.LinkAddress, fla
 			wasReachable := e.mu.neigh.State == Reachable
 			// Set state to Reachable again to refresh timers.
 			e.setStateLocked(Reachable)
-			e.notifyCompletionLocked(true /* succeeded */)
+			e.notifyCompletionLocked(nil)
 			if !wasReachable {
 				e.dispatchChangeEventLocked()
 			}

pkg/tcpip/stack/nic.go

@@ -613,7 +613,7 @@ func (n *nic) getLinkAddress(addr, localAddr tcpip.Address, protocol tcpip.Netwo
 	}
 
 	if linkAddr, ok := linkRes.resolver.ResolveStaticAddress(addr); ok {
-		onResolve(LinkResolutionResult{LinkAddress: linkAddr, Success: true})
+		onResolve(LinkResolutionResult{LinkAddress: linkAddr, Err: nil})
 		return nil
 	}
 

pkg/tcpip/stack/pending_packets.go

@@ -91,9 +91,9 @@ func (f *packetsPendingLinkResolution) init(nic *nic) {
 
 // dequeue any pending packets associated with ch.
 //
-// If success is true, packets will be written and sent to the given remote link
+// If err is nil, packets will be written and sent to the given remote link
 // address.
-func (f *packetsPendingLinkResolution) dequeue(ch <-chan struct{}, linkAddr tcpip.LinkAddress, success bool) {
+func (f *packetsPendingLinkResolution) dequeue(ch <-chan struct{}, linkAddr tcpip.LinkAddress, err tcpip.Error) {
 	f.mu.Lock()
 	packets, ok := f.mu.packets[ch]
 	delete(f.mu.packets, ch)
@@ -110,7 +110,7 @@ func (f *packetsPendingLinkResolution) dequeue(ch <-chan struct{}, linkAddr tcpi
 	f.mu.Unlock()
 
 	if ok {
-		f.dequeuePackets(packets, linkAddr, success)
+		f.dequeuePackets(packets, linkAddr, err)
 	}
 }
 
@@ -176,7 +176,7 @@ func (f *packetsPendingLinkResolution) enqueue(r *Route, gso *GSO, proto tcpip.N
 	if len(cancelledPackets) != 0 {
 		// Dequeue the pending packets in a new goroutine to not hold up the current
 		// goroutine as handing link resolution failures may be a costly operation.
-		go f.dequeuePackets(cancelledPackets, "" /* linkAddr */, false /* success */)
+		go f.dequeuePackets(cancelledPackets, "" /* linkAddr */, &tcpip.ErrAborted{})
 	}
 
 	return pkt.len(), nil
@@ -207,9 +207,9 @@ func (f *packetsPendingLinkResolution) newCancelChannelLocked(newCH <-chan struc
 	return packets
 }
 
-func (f *packetsPendingLinkResolution) dequeuePackets(packets []pendingPacket, linkAddr tcpip.LinkAddress, success bool) {
+func (f *packetsPendingLinkResolution) dequeuePackets(packets []pendingPacket, linkAddr tcpip.LinkAddress, err tcpip.Error) {
 	for _, p := range packets {
-		if success {
+		if err == nil {
 			p.routeInfo.RemoteLinkAddress = linkAddr
 			_, _ = f.nic.writePacketBuffer(p.routeInfo, p.gso, p.proto, p.pkt)
 		} else {

pkg/tcpip/stack/route.go

@@ -318,7 +318,7 @@ func (r *Route) ResolveWith(addr tcpip.LinkAddress) {
 // ResolvedFieldsResult is the result of a route resolution attempt.
 type ResolvedFieldsResult struct {
 	RouteInfo RouteInfo
-	Success   bool
+	Err       tcpip.Error
 }
 
 // ResolvedFields attempts to resolve the remote link address if it is not
@@ -349,7 +349,7 @@ func (r *Route) resolvedFields(afterResolve func(ResolvedFieldsResult)) (RouteIn
 	r.mu.RUnlock()
 	if !resolutionRequired {
 		if afterResolve != nil {
-			afterResolve(ResolvedFieldsResult{RouteInfo: fields, Success: true})
+			afterResolve(ResolvedFieldsResult{RouteInfo: fields, Err: nil})
 		}
 		return fields, nil, nil
 	}
@@ -364,11 +364,11 @@ func (r *Route) resolvedFields(afterResolve func(ResolvedFieldsResult)) (RouteIn
 	afterResolveFields := fields
 	linkAddr, ch, err := r.linkRes.getNeighborLinkAddress(r.nextHop(), linkAddressResolutionRequestLocalAddr, func(r LinkResolutionResult) {
 		if afterResolve != nil {
-			if r.Success {
+			if r.Err == nil {
 				afterResolveFields.RemoteLinkAddress = r.LinkAddress
 			}
 
-			afterResolve(ResolvedFieldsResult{RouteInfo: afterResolveFields, Success: r.Success})
+			afterResolve(ResolvedFieldsResult{RouteInfo: afterResolveFields, Err: r.Err})
 		}
 	})
 	if err == nil {

pkg/tcpip/stack/stack.go

@@ -1542,7 +1542,7 @@ func (s *Stack) SetSpoofing(nicID tcpip.NICID, enable bool) tcpip.Error {
 // LinkResolutionResult is the result of a link address resolution attempt.
 type LinkResolutionResult struct {
 	LinkAddress tcpip.LinkAddress
-	Success     bool
+	Err         tcpip.Error
 }
 
 // GetLinkAddress finds the link address corresponding to a network address.