From 8dbf428a1236f5962077e2506bef365362b953d0 Mon Sep 17 00:00:00 2001 From: Sam Balana Date: Mon, 27 Jul 2020 15:16:16 -0700 Subject: Add ability to send unicast ARP requests and Neighbor Solicitations The previous implementation of LinkAddressRequest only supported sending broadcast ARP requests and multicast Neighbor Solicitations. The ability to send these packets as unicast is required for Neighbor Unreachability Detection. Tests: pkg/tcpip/network/arp:arp_test - TestLinkAddressRequest pkg/tcpip/network/ipv6:ipv6_test - TestLinkAddressRequest Updates #1889 Updates #1894 Updates #1895 Updates #1947 Updates #1948 Updates #1949 Updates #1950 PiperOrigin-RevId: 323451569 --- pkg/tcpip/network/arp/arp.go | 7 +++-- pkg/tcpip/network/arp/arp_test.go | 58 ++++++++++++++++++++++++++++++----- pkg/tcpip/network/ipv6/icmp.go | 8 +++-- pkg/tcpip/network/ipv6/icmp_test.go | 52 +++++++++++++++++++++++++++++-- pkg/tcpip/stack/forwarder_test.go | 18 ++++++----- pkg/tcpip/stack/linkaddrcache.go | 2 +- pkg/tcpip/stack/linkaddrcache_test.go | 2 +- pkg/tcpip/stack/nic_test.go | 2 +- pkg/tcpip/stack/registration.go | 7 +++-- 9 files changed, 128 insertions(+), 28 deletions(-) (limited to 'pkg/tcpip') diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go index b0f57040c..31a242482 100644 --- a/pkg/tcpip/network/arp/arp.go +++ b/pkg/tcpip/network/arp/arp.go @@ -160,9 +160,12 @@ func (*protocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber { } // LinkAddressRequest implements stack.LinkAddressResolver.LinkAddressRequest. -func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack.LinkEndpoint) *tcpip.Error { +func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, linkEP stack.LinkEndpoint) *tcpip.Error { r := &stack.Route{ - RemoteLinkAddress: header.EthernetBroadcastAddress, + RemoteLinkAddress: remoteLinkAddr, + } + if len(r.RemoteLinkAddress) == 0 { + r.RemoteLinkAddress = header.EthernetBroadcastAddress } hdr := buffer.NewPrependable(int(linkEP.MaxHeaderLength()) + header.ARPSize) diff --git a/pkg/tcpip/network/arp/arp_test.go b/pkg/tcpip/network/arp/arp_test.go index 66e67429c..a35a64a0f 100644 --- a/pkg/tcpip/network/arp/arp_test.go +++ b/pkg/tcpip/network/arp/arp_test.go @@ -32,10 +32,14 @@ import ( ) const ( - stackLinkAddr = tcpip.LinkAddress("\x0a\x0a\x0b\x0b\x0c\x0c") - stackAddr1 = tcpip.Address("\x0a\x00\x00\x01") - stackAddr2 = tcpip.Address("\x0a\x00\x00\x02") - stackAddrBad = tcpip.Address("\x0a\x00\x00\x03") + stackLinkAddr1 = tcpip.LinkAddress("\x0a\x0a\x0b\x0b\x0c\x0c") + stackLinkAddr2 = tcpip.LinkAddress("\x0b\x0b\x0c\x0c\x0d\x0d") + stackAddr1 = tcpip.Address("\x0a\x00\x00\x01") + stackAddr2 = tcpip.Address("\x0a\x00\x00\x02") + stackAddrBad = tcpip.Address("\x0a\x00\x00\x03") + + defaultChannelSize = 1 + defaultMTU = 65536 ) type testContext struct { @@ -50,8 +54,7 @@ func newTestContext(t *testing.T) *testContext { TransportProtocols: []stack.TransportProtocol{icmp.NewProtocol4()}, }) - const defaultMTU = 65536 - ep := channel.New(256, defaultMTU, stackLinkAddr) + ep := channel.New(defaultChannelSize, defaultMTU, stackLinkAddr1) wep := stack.LinkEndpoint(ep) if testing.Verbose() { @@ -119,7 +122,7 @@ func TestDirectRequest(t *testing.T) { if !rep.IsValid() { t.Fatalf("invalid ARP response pi.Pkt.Header.UsedLength()=%d", pi.Pkt.Header.UsedLength()) } - if got, want := tcpip.LinkAddress(rep.HardwareAddressSender()), stackLinkAddr; got != want { + if got, want := tcpip.LinkAddress(rep.HardwareAddressSender()), stackLinkAddr1; got != want { t.Errorf("got HardwareAddressSender = %s, want = %s", got, want) } if got, want := tcpip.Address(rep.ProtocolAddressSender()), tcpip.Address(h.ProtocolAddressTarget()); got != want { @@ -144,3 +147,44 @@ func TestDirectRequest(t *testing.T) { t.Errorf("stackAddrBad: unexpected packet sent, Proto=%v", pkt.Proto) } } + +func TestLinkAddressRequest(t *testing.T) { + tests := []struct { + name string + remoteLinkAddr tcpip.LinkAddress + expectLinkAddr tcpip.LinkAddress + }{ + { + name: "Unicast", + remoteLinkAddr: stackLinkAddr2, + expectLinkAddr: stackLinkAddr2, + }, + { + name: "Multicast", + remoteLinkAddr: "", + expectLinkAddr: header.EthernetBroadcastAddress, + }, + } + + for _, test := range tests { + p := arp.NewProtocol() + linkRes, ok := p.(stack.LinkAddressResolver) + if !ok { + t.Fatal("expected ARP protocol to implement stack.LinkAddressResolver") + } + + linkEP := channel.New(defaultChannelSize, defaultMTU, stackLinkAddr1) + if err := linkRes.LinkAddressRequest(stackAddr1, stackAddr2, test.remoteLinkAddr, linkEP); err != nil { + t.Errorf("got p.LinkAddressRequest(%s, %s, %s, _) = %s", stackAddr1, stackAddr2, test.remoteLinkAddr, err) + } + + pkt, ok := linkEP.Read() + if !ok { + t.Fatal("expected to send a link address request") + } + + if got, want := pkt.Route.RemoteLinkAddress, test.expectLinkAddr; got != want { + t.Errorf("got pkt.Route.RemoteLinkAddress = %s, want = %s", got, want) + } + } +} diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index ff1cb53dd..24600d877 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -504,7 +504,7 @@ func (*protocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber { } // LinkAddressRequest implements stack.LinkAddressResolver. -func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack.LinkEndpoint) *tcpip.Error { +func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, linkEP stack.LinkEndpoint) *tcpip.Error { snaddr := header.SolicitedNodeAddr(addr) // TODO(b/148672031): Use stack.FindRoute instead of manually creating the @@ -513,8 +513,12 @@ func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack. r := &stack.Route{ LocalAddress: localAddr, RemoteAddress: snaddr, - RemoteLinkAddress: header.EthernetAddressFromMulticastIPv6Address(snaddr), + RemoteLinkAddress: remoteLinkAddr, } + if len(r.RemoteLinkAddress) == 0 { + r.RemoteLinkAddress = header.EthernetAddressFromMulticastIPv6Address(snaddr) + } + hdr := buffer.NewPrependable(int(linkEP.MaxHeaderLength()) + header.IPv6MinimumSize + header.ICMPv6NeighborAdvertSize) pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborAdvertSize)) pkt.SetType(header.ICMPv6NeighborSolicit) diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go index 52a01b44e..f86aaed1d 100644 --- a/pkg/tcpip/network/ipv6/icmp_test.go +++ b/pkg/tcpip/network/ipv6/icmp_test.go @@ -34,6 +34,9 @@ const ( linkAddr0 = tcpip.LinkAddress("\x02\x02\x03\x04\x05\x06") linkAddr1 = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0e") linkAddr2 = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0f") + + defaultChannelSize = 1 + defaultMTU = 65536 ) var ( @@ -257,8 +260,7 @@ func newTestContext(t *testing.T) *testContext { }), } - const defaultMTU = 65536 - c.linkEP0 = channel.New(256, defaultMTU, linkAddr0) + c.linkEP0 = channel.New(defaultChannelSize, defaultMTU, linkAddr0) wrappedEP0 := stack.LinkEndpoint(endpointWithResolutionCapability{LinkEndpoint: c.linkEP0}) if testing.Verbose() { @@ -271,7 +273,7 @@ func newTestContext(t *testing.T) *testContext { t.Fatalf("AddAddress lladdr0: %v", err) } - c.linkEP1 = channel.New(256, defaultMTU, linkAddr1) + c.linkEP1 = channel.New(defaultChannelSize, defaultMTU, linkAddr1) wrappedEP1 := stack.LinkEndpoint(endpointWithResolutionCapability{LinkEndpoint: c.linkEP1}) if err := c.s1.CreateNIC(1, wrappedEP1); err != nil { t.Fatalf("CreateNIC failed: %v", err) @@ -951,3 +953,47 @@ func TestICMPChecksumValidationWithPayloadMultipleViews(t *testing.T) { }) } } + +func TestLinkAddressRequest(t *testing.T) { + snaddr := header.SolicitedNodeAddr(lladdr0) + mcaddr := header.EthernetAddressFromMulticastIPv6Address(snaddr) + + tests := []struct { + name string + remoteLinkAddr tcpip.LinkAddress + expectLinkAddr tcpip.LinkAddress + }{ + { + name: "Unicast", + remoteLinkAddr: linkAddr1, + expectLinkAddr: linkAddr1, + }, + { + name: "Multicast", + remoteLinkAddr: "", + expectLinkAddr: mcaddr, + }, + } + + for _, test := range tests { + p := NewProtocol() + linkRes, ok := p.(stack.LinkAddressResolver) + if !ok { + t.Fatalf("expected IPv6 protocol to implement stack.LinkAddressResolver") + } + + linkEP := channel.New(defaultChannelSize, defaultMTU, linkAddr0) + if err := linkRes.LinkAddressRequest(lladdr0, lladdr1, test.remoteLinkAddr, linkEP); err != nil { + t.Errorf("got p.LinkAddressRequest(%s, %s, %s, _) = %s", lladdr0, lladdr1, test.remoteLinkAddr, err) + } + + pkt, ok := linkEP.Read() + if !ok { + t.Fatal("expected to send a link address request") + } + + if got, want := pkt.Route.RemoteLinkAddress, test.expectLinkAddr; got != want { + t.Errorf("got pkt.Route.RemoteLinkAddress = %s, want = %s", got, want) + } + } +} diff --git a/pkg/tcpip/stack/forwarder_test.go b/pkg/tcpip/stack/forwarder_test.go index bca1d940b..c962693f5 100644 --- a/pkg/tcpip/stack/forwarder_test.go +++ b/pkg/tcpip/stack/forwarder_test.go @@ -121,10 +121,12 @@ func (*fwdTestNetworkEndpoint) Close() {} type fwdTestNetworkProtocol struct { addrCache *linkAddrCache addrResolveDelay time.Duration - onLinkAddressResolved func(cache *linkAddrCache, addr tcpip.Address) + onLinkAddressResolved func(cache *linkAddrCache, addr tcpip.Address, _ tcpip.LinkAddress) onResolveStaticAddress func(tcpip.Address) (tcpip.LinkAddress, bool) } +var _ LinkAddressResolver = (*fwdTestNetworkProtocol)(nil) + func (f *fwdTestNetworkProtocol) Number() tcpip.NetworkProtocolNumber { return fwdTestNetNumber } @@ -174,10 +176,10 @@ func (f *fwdTestNetworkProtocol) Close() {} func (f *fwdTestNetworkProtocol) Wait() {} -func (f *fwdTestNetworkProtocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP LinkEndpoint) *tcpip.Error { +func (f *fwdTestNetworkProtocol) LinkAddressRequest(addr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, linkEP LinkEndpoint) *tcpip.Error { if f.addrCache != nil && f.onLinkAddressResolved != nil { time.AfterFunc(f.addrResolveDelay, func() { - f.onLinkAddressResolved(f.addrCache, addr) + f.onLinkAddressResolved(f.addrCache, addr, remoteLinkAddr) }) } return nil @@ -405,7 +407,7 @@ func TestForwardingWithFakeResolver(t *testing.T) { // Create a network protocol with a fake resolver. proto := &fwdTestNetworkProtocol{ addrResolveDelay: 500 * time.Millisecond, - onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) { + onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address, _ tcpip.LinkAddress) { // Any address will be resolved to the link address "c". cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c") }, @@ -463,7 +465,7 @@ func TestForwardingWithFakeResolverPartialTimeout(t *testing.T) { // Create a network protocol with a fake resolver. proto := &fwdTestNetworkProtocol{ addrResolveDelay: 500 * time.Millisecond, - onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) { + onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address, _ tcpip.LinkAddress) { // Only packets to address 3 will be resolved to the // link address "c". if addr == "\x03" { @@ -515,7 +517,7 @@ func TestForwardingWithFakeResolverTwoPackets(t *testing.T) { // Create a network protocol with a fake resolver. proto := &fwdTestNetworkProtocol{ addrResolveDelay: 500 * time.Millisecond, - onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) { + onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address, _ tcpip.LinkAddress) { // Any packets will be resolved to the link address "c". cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c") }, @@ -559,7 +561,7 @@ func TestForwardingWithFakeResolverManyPackets(t *testing.T) { // Create a network protocol with a fake resolver. proto := &fwdTestNetworkProtocol{ addrResolveDelay: 500 * time.Millisecond, - onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) { + onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address, _ tcpip.LinkAddress) { // Any packets will be resolved to the link address "c". cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c") }, @@ -616,7 +618,7 @@ func TestForwardingWithFakeResolverManyResolutions(t *testing.T) { // Create a network protocol with a fake resolver. proto := &fwdTestNetworkProtocol{ addrResolveDelay: 500 * time.Millisecond, - onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address) { + onLinkAddressResolved: func(cache *linkAddrCache, addr tcpip.Address, _ tcpip.LinkAddress) { // Any packets will be resolved to the link address "c". cache.add(tcpip.FullAddress{NIC: 2, Addr: addr}, "c") }, diff --git a/pkg/tcpip/stack/linkaddrcache.go b/pkg/tcpip/stack/linkaddrcache.go index 403557fd7..6f73a0ce4 100644 --- a/pkg/tcpip/stack/linkaddrcache.go +++ b/pkg/tcpip/stack/linkaddrcache.go @@ -244,7 +244,7 @@ func (c *linkAddrCache) startAddressResolution(k tcpip.FullAddress, linkRes Link for i := 0; ; i++ { // Send link request, then wait for the timeout limit and check // whether the request succeeded. - linkRes.LinkAddressRequest(k.Addr, localAddr, linkEP) + linkRes.LinkAddressRequest(k.Addr, localAddr, "" /* linkAddr */, linkEP) select { case now := <-time.After(c.resolutionTimeout): diff --git a/pkg/tcpip/stack/linkaddrcache_test.go b/pkg/tcpip/stack/linkaddrcache_test.go index 1baa498d0..b15b8d1cb 100644 --- a/pkg/tcpip/stack/linkaddrcache_test.go +++ b/pkg/tcpip/stack/linkaddrcache_test.go @@ -48,7 +48,7 @@ type testLinkAddressResolver struct { onLinkAddressRequest func() } -func (r *testLinkAddressResolver) LinkAddressRequest(addr, _ tcpip.Address, _ LinkEndpoint) *tcpip.Error { +func (r *testLinkAddressResolver) LinkAddressRequest(addr, _ tcpip.Address, _ tcpip.LinkAddress, _ LinkEndpoint) *tcpip.Error { time.AfterFunc(r.delay, func() { r.fakeRequest(addr) }) if f := r.onLinkAddressRequest; f != nil { f() diff --git a/pkg/tcpip/stack/nic_test.go b/pkg/tcpip/stack/nic_test.go index c477e31d8..a70792b50 100644 --- a/pkg/tcpip/stack/nic_test.go +++ b/pkg/tcpip/stack/nic_test.go @@ -243,7 +243,7 @@ func (*testIPv6Protocol) LinkAddressProtocol() tcpip.NetworkProtocolNumber { } // LinkAddressRequest implements LinkAddressResolver. -func (*testIPv6Protocol) LinkAddressRequest(_, _ tcpip.Address, _ LinkEndpoint) *tcpip.Error { +func (*testIPv6Protocol) LinkAddressRequest(_, _ tcpip.Address, _ tcpip.LinkAddress, _ LinkEndpoint) *tcpip.Error { return nil } diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go index 9e1b2d25f..8604c4259 100644 --- a/pkg/tcpip/stack/registration.go +++ b/pkg/tcpip/stack/registration.go @@ -478,12 +478,13 @@ type InjectableLinkEndpoint interface { // A LinkAddressResolver is an extension to a NetworkProtocol that // can resolve link addresses. type LinkAddressResolver interface { - // LinkAddressRequest sends a request for the LinkAddress of addr. - // The request is sent on linkEP with localAddr as the source. + // LinkAddressRequest sends a request for the LinkAddress of addr. Broadcasts + // the request on the local network if remoteLinkAddr is the zero value. The + // request is sent on linkEP with localAddr as the source. // // A valid response will cause the discovery protocol's network // endpoint to call AddLinkAddress. - LinkAddressRequest(addr, localAddr tcpip.Address, linkEP LinkEndpoint) *tcpip.Error + LinkAddressRequest(addr, localAddr tcpip.Address, remoteLinkAddr tcpip.LinkAddress, linkEP LinkEndpoint) *tcpip.Error // ResolveStaticAddress attempts to resolve address without sending // requests. It either resolves the name immediately or returns the -- cgit v1.2.3