Add per endpoint ARP statistics

The ARP stat NetworkUnreachable was removed, and was replaced by
InterfaceHasNoLocalAddress. No stats are recorded when dealing with an
missing endpoint (ErrNotConnected) (because if there is no endpoint,
there is no valid per-endpoint stats).

PiperOrigin-RevId: 353759462

1 files changed, 63 insertions, 27 deletions

diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go
index 0616b10aa..6bc8c5c02 100644
--- a/pkg/tcpip/network/arp/arp.go
+++ b/pkg/tcpip/network/arp/arp.go
@@ -19,8 +19,10 @@ package arp
 
 import (
 	"fmt"
+	"reflect"
 	"sync/atomic"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
@@ -50,6 +52,7 @@ type endpoint struct {
 	nic           stack.NetworkInterface
 	linkAddrCache stack.LinkAddressCache
 	nud           stack.NUDHandler
+	stats         sharedStats
 }
 
 func (e *endpoint) Enable() *tcpip.Error {
@@ -98,7 +101,9 @@ func (e *endpoint) MaxHeaderLength() uint16 {
 	return e.nic.MaxHeaderLength() + header.ARPSize
 }
 
-func (*endpoint) Close() {}
+func (e *endpoint) Close() {
+	e.protocol.forgetEndpoint(e.nic.ID())
+}
 
 func (*endpoint) WritePacket(*stack.Route, *stack.GSO, stack.NetworkHeaderParams, *stack.PacketBuffer) *tcpip.Error {
 	return tcpip.ErrNotSupported
@@ -119,27 +124,27 @@ func (*endpoint) WriteHeaderIncludedPacket(*stack.Route, *stack.PacketBuffer) *t
 }
 
 func (e *endpoint) HandlePacket(pkt *stack.PacketBuffer) {
-	stats := e.protocol.stack.Stats().ARP
-	stats.PacketsReceived.Increment()
+	stats := e.stats.arp
+	stats.packetsReceived.Increment()
 
 	if !e.isEnabled() {
-		stats.DisabledPacketsReceived.Increment()
+		stats.disabledPacketsReceived.Increment()
 		return
 	}
 
 	h := header.ARP(pkt.NetworkHeader().View())
 	if !h.IsValid() {
-		stats.MalformedPacketsReceived.Increment()
+		stats.malformedPacketsReceived.Increment()
 		return
 	}
 
 	switch h.Op() {
 	case header.ARPRequest:
-		stats.RequestsReceived.Increment()
+		stats.requestsReceived.Increment()
 		localAddr := tcpip.Address(h.ProtocolAddressTarget())
 
 		if e.protocol.stack.CheckLocalAddress(e.nic.ID(), header.IPv4ProtocolNumber, localAddr) == 0 {
-			stats.RequestsReceivedUnknownTargetAddress.Increment()
+			stats.requestsReceivedUnknownTargetAddress.Increment()
 			return // we have no useful answer, ignore the request
 		}
 
@@ -180,13 +185,13 @@ func (e *endpoint) HandlePacket(pkt *stack.PacketBuffer) {
 		//   Send the packet to the (new) target hardware address on the same
 		//   hardware on which the request was received.
 		if err := e.nic.WritePacketToRemote(tcpip.LinkAddress(origSender), nil /* gso */, ProtocolNumber, respPkt); err != nil {
-			stats.OutgoingRepliesDropped.Increment()
+			stats.outgoingRepliesDropped.Increment()
 		} else {
-			stats.OutgoingRepliesSent.Increment()
+			stats.outgoingRepliesSent.Increment()
 		}
 
 	case header.ARPReply:
-		stats.RepliesReceived.Increment()
+		stats.repliesReceived.Increment()
 		addr := tcpip.Address(h.ProtocolAddressSender())
 		linkAddr := tcpip.LinkAddress(h.HardwareAddressSender())
 
@@ -212,21 +217,23 @@ func (e *endpoint) HandlePacket(pkt *stack.PacketBuffer) {
 
 // Stats implements stack.NetworkEndpoint.
 func (e *endpoint) Stats() stack.NetworkEndpointStats {
-	// TODO(gvisor.dev/issues/4963): Record statistics for ARP.
-	return &Stats{}
+	return &e.stats.localStats
 }
 
-var _ stack.NetworkEndpointStats = (*Stats)(nil)
-
-// Stats holds ARP statistics.
-type Stats struct{}
-
-// IsNetworkEndpointStats implements stack.NetworkEndpointStats.
-func (*Stats) IsNetworkEndpointStats() {}
+var _ stack.NetworkProtocol = (*protocol)(nil)
+var _ stack.LinkAddressResolver = (*protocol)(nil)
 
 // protocol implements stack.NetworkProtocol and stack.LinkAddressResolver.
 type protocol struct {
 	stack *stack.Stack
+
+	mu struct {
+		sync.RWMutex
+
+		// eps is keyed by NICID to allow protocol methods to retrieve the correct
+		// endpoint depending on the NIC.
+		eps map[tcpip.NICID]*endpoint
+	}
 }
 
 func (p *protocol) Number() tcpip.NetworkProtocolNumber { return ProtocolNumber }
@@ -244,9 +251,25 @@ func (p *protocol) NewEndpoint(nic stack.NetworkInterface, linkAddrCache stack.L
 		linkAddrCache: linkAddrCache,
 		nud:           nud,
 	}
+
+	tcpip.InitStatCounters(reflect.ValueOf(&e.stats.localStats).Elem())
+
+	stackStats := p.stack.Stats()
+	e.stats.arp.init(&e.stats.localStats.ARP, &stackStats.ARP)
+
+	p.mu.Lock()
+	p.mu.eps[nic.ID()] = e
+	p.mu.Unlock()
+
 	return e
 }
 
+func (p *protocol) forgetEndpoint(nicID tcpip.NICID) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	delete(p.mu.eps, nicID)
+}
+
 // LinkAddressProtocol implements stack.LinkAddressResolver.LinkAddressProtocol.
 func (*protocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber {
 	return header.IPv4ProtocolNumber
@@ -254,28 +277,35 @@ func (*protocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber {
 
 // LinkAddressRequest implements stack.LinkAddressResolver.LinkAddressRequest.
 func (p *protocol) LinkAddressRequest(targetAddr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, nic stack.NetworkInterface) *tcpip.Error {
-	stats := p.stack.Stats().ARP
+	nicID := nic.ID()
+
+	p.mu.Lock()
+	netEP, ok := p.mu.eps[nicID]
+	p.mu.Unlock()
+	if !ok {
+		return tcpip.ErrNotConnected
+	}
+
+	stats := netEP.stats.arp
 
 	if len(remoteLinkAddr) == 0 {
 		remoteLinkAddr = header.EthernetBroadcastAddress
 	}
 
-	nicID := nic.ID()
 	if len(localAddr) == 0 {
 		addr, ok := p.stack.GetMainNICAddress(nicID, header.IPv4ProtocolNumber)
 		if !ok {
-			stats.OutgoingRequestInterfaceHasNoLocalAddressErrors.Increment()
 			return tcpip.ErrUnknownNICID
 		}
 
 		if len(addr.Address) == 0 {
-			stats.OutgoingRequestNetworkUnreachableErrors.Increment()
+			stats.outgoingRequestInterfaceHasNoLocalAddressErrors.Increment()
 			return tcpip.ErrNetworkUnreachable
 		}
 
 		localAddr = addr.Address
 	} else if p.stack.CheckLocalAddress(nicID, header.IPv4ProtocolNumber, localAddr) == 0 {
-		stats.OutgoingRequestBadLocalAddressErrors.Increment()
+		stats.outgoingRequestBadLocalAddressErrors.Increment()
 		return tcpip.ErrBadLocalAddress
 	}
 
@@ -296,10 +326,10 @@ func (p *protocol) LinkAddressRequest(targetAddr, localAddr tcpip.Address, remot
 		panic(fmt.Sprintf("copied %d bytes, expected %d bytes", n, header.IPv4AddressSize))
 	}
 	if err := nic.WritePacketToRemote(remoteLinkAddr, nil /* gso */, ProtocolNumber, pkt); err != nil {
-		stats.OutgoingRequestsDropped.Increment()
+		stats.outgoingRequestsDropped.Increment()
 		return err
 	}
-	stats.OutgoingRequestsSent.Increment()
+	stats.outgoingRequestsSent.Increment()
 	return nil
 }
 
@@ -337,5 +367,11 @@ func (*protocol) Parse(pkt *stack.PacketBuffer) (proto tcpip.TransportProtocolNu
 
 // NewProtocol returns an ARP network protocol.
 func NewProtocol(s *stack.Stack) stack.NetworkProtocol {
-	return &protocol{stack: s}
+	return &protocol{
+		stack: s,
+		mu: struct {
+			sync.RWMutex
+			eps map[tcpip.NICID]*endpoint
+		}{eps: make(map[tcpip.NICID]*endpoint)},
+	}
 }