diff options
-rw-r--r-- | pkg/tcpip/checker/checker.go | 81 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/BUILD | 1 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/icmp.go | 125 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/icmp_test.go | 3 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/ndp_test.go | 252 |
5 files changed, 414 insertions, 48 deletions
diff --git a/pkg/tcpip/checker/checker.go b/pkg/tcpip/checker/checker.go index 8dc0f7c0e..307f1b666 100644 --- a/pkg/tcpip/checker/checker.go +++ b/pkg/tcpip/checker/checker.go @@ -728,7 +728,7 @@ func ICMPv6Code(want byte) TransportChecker { // message for type of ty, with potentially additional checks specified by // checkers. // -// checkers may assume that a valid ICMPv6 is passed to it containing a valid +// Checkers may assume that a valid ICMPv6 is passed to it containing a valid // NDP message as far as the size of the message (minSize) is concerned. The // values within the message are up to checkers to validate. func NDP(msgType header.ICMPv6Type, minSize int, checkers ...TransportChecker) NetworkChecker { @@ -760,9 +760,9 @@ func NDP(msgType header.ICMPv6Type, minSize int, checkers ...TransportChecker) N // Neighbor Solicitation message (as per the raw wire format), with potentially // additional checks specified by checkers. // -// checkers may assume that a valid ICMPv6 is passed to it containing a valid -// NDPNS message as far as the size of the messages concerned. The values within -// the message are up to checkers to validate. +// Checkers may assume that a valid ICMPv6 is passed to it containing a valid +// NDPNS message as far as the size of the message is concerned. The values +// within the message are up to checkers to validate. func NDPNS(checkers ...TransportChecker) NetworkChecker { return NDP(header.ICMPv6NeighborSolicit, header.NDPNSMinimumSize, checkers...) } @@ -780,7 +780,54 @@ func NDPNSTargetAddress(want tcpip.Address) TransportChecker { ns := header.NDPNeighborSolicit(icmp.NDPPayload()) if got := ns.TargetAddress(); got != want { - t.Fatalf("got %T.TargetAddress = %s, want = %s", ns, got, want) + t.Errorf("got %T.TargetAddress() = %s, want = %s", ns, got, want) + } + } +} + +// NDPNA creates a checker that checks that the packet contains a valid NDP +// Neighbor Advertisement message (as per the raw wire format), with potentially +// additional checks specified by checkers. +// +// Checkers may assume that a valid ICMPv6 is passed to it containing a valid +// NDPNA message as far as the size of the message is concerned. The values +// within the message are up to checkers to validate. +func NDPNA(checkers ...TransportChecker) NetworkChecker { + return NDP(header.ICMPv6NeighborAdvert, header.NDPNAMinimumSize, checkers...) +} + +// NDPNATargetAddress creates a checker that checks the Target Address field of +// a header.NDPNeighborAdvert. +// +// The returned TransportChecker assumes that a valid ICMPv6 is passed to it +// containing a valid NDPNA message as far as the size is concerned. +func NDPNATargetAddress(want tcpip.Address) TransportChecker { + return func(t *testing.T, h header.Transport) { + t.Helper() + + icmp := h.(header.ICMPv6) + na := header.NDPNeighborAdvert(icmp.NDPPayload()) + + if got := na.TargetAddress(); got != want { + t.Errorf("got %T.TargetAddress() = %s, want = %s", na, got, want) + } + } +} + +// NDPNASolicitedFlag creates a checker that checks the Solicited field of +// a header.NDPNeighborAdvert. +// +// The returned TransportChecker assumes that a valid ICMPv6 is passed to it +// containing a valid NDPNA message as far as the size is concerned. +func NDPNASolicitedFlag(want bool) TransportChecker { + return func(t *testing.T, h header.Transport) { + t.Helper() + + icmp := h.(header.ICMPv6) + na := header.NDPNeighborAdvert(icmp.NDPPayload()) + + if got := na.SolicitedFlag(); got != want { + t.Errorf("got %T.SolicitedFlag = %t, want = %t", na, got, want) } } } @@ -819,6 +866,13 @@ func ndpOptions(t *testing.T, optsBuf header.NDPOptions, opts []header.NDPOption } else if got, want := gotOpt.EthernetAddress(), wantOpt.EthernetAddress(); got != want { t.Errorf("got EthernetAddress() = %s at index %d, want = %s", got, i, want) } + case header.NDPTargetLinkLayerAddressOption: + gotOpt, ok := opt.(header.NDPTargetLinkLayerAddressOption) + if !ok { + t.Errorf("got type = %T at index = %d; want = %T", opt, i, wantOpt) + } else if got, want := gotOpt.EthernetAddress(), wantOpt.EthernetAddress(); got != want { + t.Errorf("got EthernetAddress() = %s at index %d, want = %s", got, i, want) + } default: t.Fatalf("checker not implemented for expected NDP option: %T", wantOpt) } @@ -831,6 +885,21 @@ func ndpOptions(t *testing.T, optsBuf header.NDPOptions, opts []header.NDPOption } } +// NDPNAOptions creates a checker that checks that the packet contains the +// provided NDP options within an NDP Neighbor Solicitation message. +// +// The returned TransportChecker assumes that a valid ICMPv6 is passed to it +// containing a valid NDPNA message as far as the size is concerned. +func NDPNAOptions(opts []header.NDPOption) TransportChecker { + return func(t *testing.T, h header.Transport) { + t.Helper() + + icmp := h.(header.ICMPv6) + na := header.NDPNeighborAdvert(icmp.NDPPayload()) + ndpOptions(t, na.Options(), opts) + } +} + // NDPNSOptions creates a checker that checks that the packet contains the // provided NDP options within an NDP Neighbor Solicitation message. // @@ -849,7 +918,7 @@ func NDPNSOptions(opts []header.NDPOption) TransportChecker { // NDPRS creates a checker that checks that the packet contains a valid NDP // Router Solicitation message (as per the raw wire format). // -// checkers may assume that a valid ICMPv6 is passed to it containing a valid +// Checkers may assume that a valid ICMPv6 is passed to it containing a valid // NDPRS as far as the size of the message is concerned. The values within the // message are up to checkers to validate. func NDPRS(checkers ...TransportChecker) NetworkChecker { diff --git a/pkg/tcpip/network/ipv6/BUILD b/pkg/tcpip/network/ipv6/BUILD index a93a7621a..3f71fc520 100644 --- a/pkg/tcpip/network/ipv6/BUILD +++ b/pkg/tcpip/network/ipv6/BUILD @@ -31,6 +31,7 @@ go_test( deps = [ "//pkg/tcpip", "//pkg/tcpip/buffer", + "//pkg/tcpip/checker", "//pkg/tcpip/header", "//pkg/tcpip/link/channel", "//pkg/tcpip/link/sniffer", diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index f91180aa3..dc0369156 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -138,53 +138,48 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P targetAddr := ns.TargetAddress() s := r.Stack() - rxNICID := r.NICID() - if isTentative, err := s.IsAddrTentative(rxNICID, targetAddr); err != nil { - // We will only get an error if rxNICID is unrecognized, - // which should not happen. For now short-circuit this - // packet. + if isTentative, err := s.IsAddrTentative(e.nicID, targetAddr); err != nil { + // We will only get an error if the NIC is unrecognized, which should not + // happen. For now, drop this packet. // // TODO(b/141002840): Handle this better? return } else if isTentative { - // If the target address is tentative and the source - // of the packet is a unicast (specified) address, then - // the source of the packet is attempting to perform - // address resolution on the target. In this case, the - // solicitation is silently ignored, as per RFC 4862 - // section 5.4.3. + // If the target address is tentative and the source of the packet is a + // unicast (specified) address, then the source of the packet is + // attempting to perform address resolution on the target. In this case, + // the solicitation is silently ignored, as per RFC 4862 section 5.4.3. // - // If the target address is tentative and the source of - // the packet is the unspecified address (::), then we - // know another node is also performing DAD for the - // same address (since targetAddr is tentative for us, - // we know we are also performing DAD on it). In this - // case we let the stack know so it can handle such a - // scenario and do nothing further with the NDP NS. - if iph.SourceAddress() == header.IPv6Any { - s.DupTentativeAddrDetected(rxNICID, targetAddr) + // If the target address is tentative and the source of the packet is the + // unspecified address (::), then we know another node is also performing + // DAD for the same address (since the target address is tentative for us, + // we know we are also performing DAD on it). In this case we let the + // stack know so it can handle such a scenario and do nothing further with + // the NS. + if r.RemoteAddress == header.IPv6Any { + s.DupTentativeAddrDetected(e.nicID, targetAddr) } - // Do not handle neighbor solicitations targeted - // to an address that is tentative on the received - // NIC any further. + // Do not handle neighbor solicitations targeted to an address that is + // tentative on the NIC any further. return } - // At this point we know that targetAddr is not tentative on - // rxNICID so the packet is processed as defined in RFC 4861, - // as per RFC 4862 section 5.4.3. + // At this point we know that the target address is not tentative on the NIC + // so the packet is processed as defined in RFC 4861, as per RFC 4862 + // section 5.4.3. + // Is the NS targetting us? if e.linkAddrCache.CheckLocalAddress(e.nicID, ProtocolNumber, targetAddr) == 0 { - // We don't have a useful answer; the best we can do is ignore the request. return } - // If the NS message has the source link layer option, update the link - // address cache with the link address for the sender of the message. + // If the NS message contains the Source Link-Layer Address option, update + // the link address cache with the value of the option. // // TODO(b/148429853): Properly process the NS message and do Neighbor // Unreachability Detection. + var sourceLinkAddr tcpip.LinkAddress for { opt, done, err := it.Next() if err != nil { @@ -197,22 +192,36 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P switch opt := opt.(type) { case header.NDPSourceLinkLayerAddressOption: - e.linkAddrCache.AddLinkAddress(e.nicID, r.RemoteAddress, opt.EthernetAddress()) + // No RFCs define what to do when an NS message has multiple Source + // Link-Layer Address options. Since no interface can have multiple + // link-layer addresses, we consider such messages invalid. + if len(sourceLinkAddr) != 0 { + received.Invalid.Increment() + return + } + + sourceLinkAddr = opt.EthernetAddress() } } - optsSerializer := header.NDPOptionsSerializer{ - header.NDPTargetLinkLayerAddressOption(r.LocalLinkAddress[:]), + unspecifiedSource := r.RemoteAddress == header.IPv6Any + + // As per RFC 4861 section 4.3, the Source Link-Layer Address Option MUST + // NOT be included when the source IP address is the unspecified address. + // Otherwise, on link layers that have addresses this option MUST be + // included in multicast solicitations and SHOULD be included in unicast + // solicitations. + if len(sourceLinkAddr) == 0 { + if header.IsV6MulticastAddress(r.LocalAddress) && !unspecifiedSource { + received.Invalid.Increment() + return + } + } else if unspecifiedSource { + received.Invalid.Increment() + return + } else { + e.linkAddrCache.AddLinkAddress(e.nicID, r.RemoteAddress, sourceLinkAddr) } - hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6NeighborAdvertMinimumSize + int(optsSerializer.Length())) - packet := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborAdvertSize)) - packet.SetType(header.ICMPv6NeighborAdvert) - na := header.NDPNeighborAdvert(packet.NDPPayload()) - na.SetSolicitedFlag(true) - na.SetOverrideFlag(true) - na.SetTargetAddress(targetAddr) - opts := na.Options() - opts.Serialize(optsSerializer) // ICMPv6 Neighbor Solicit messages are always sent to // specially crafted IPv6 multicast addresses. As a result, the @@ -225,6 +234,40 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P r := r.Clone() defer r.Release() r.LocalAddress = targetAddr + + // As per RFC 4861 section 7.2.4, if the the source of the solicitation is + // the unspecified address, the node MUST set the Solicited flag to zero and + // multicast the advertisement to the all-nodes address. + solicited := true + if unspecifiedSource { + solicited = false + r.RemoteAddress = header.IPv6AllNodesMulticastAddress + } + + // If the NS has a source link-layer option, use the link address it + // specifies as the remote link address for the response instead of the + // source link address of the packet. + // + // TODO(#2401): As per RFC 4861 section 7.2.4 we should consult our link + // address cache for the right destination link address instead of manually + // patching the route with the remote link address if one is specified in a + // Source Link-Layer Address option. + if len(sourceLinkAddr) != 0 { + r.RemoteLinkAddress = sourceLinkAddr + } + + optsSerializer := header.NDPOptionsSerializer{ + header.NDPTargetLinkLayerAddressOption(r.LocalLinkAddress), + } + hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6NeighborAdvertMinimumSize + int(optsSerializer.Length())) + packet := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborAdvertSize)) + packet.SetType(header.ICMPv6NeighborAdvert) + na := header.NDPNeighborAdvert(packet.NDPPayload()) + na.SetSolicitedFlag(solicited) + na.SetOverrideFlag(true) + na.SetTargetAddress(targetAddr) + opts := na.Options() + opts.Serialize(optsSerializer) packet.SetChecksum(header.ICMPv6Checksum(packet, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) // RFC 4861 Neighbor Discovery for IP version 6 (IPv6) diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go index bae09ed94..bd099a7f8 100644 --- a/pkg/tcpip/network/ipv6/icmp_test.go +++ b/pkg/tcpip/network/ipv6/icmp_test.go @@ -32,7 +32,8 @@ import ( const ( linkAddr0 = tcpip.LinkAddress("\x02\x02\x03\x04\x05\x06") - linkAddr1 = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0f") + linkAddr1 = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0e") + linkAddr2 = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0f") ) var ( diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go index b113aaacc..8db51da96 100644 --- a/pkg/tcpip/network/ipv6/ndp_test.go +++ b/pkg/tcpip/network/ipv6/ndp_test.go @@ -20,6 +20,7 @@ import ( "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" + "gvisor.dev/gvisor/pkg/tcpip/checker" "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/link/channel" "gvisor.dev/gvisor/pkg/tcpip/stack" @@ -173,6 +174,257 @@ func TestNeighorSolicitationWithSourceLinkLayerOption(t *testing.T) { } } +func TestNeighorSolicitationResponse(t *testing.T) { + const nicID = 1 + nicAddr := lladdr0 + remoteAddr := lladdr1 + nicAddrSNMC := header.SolicitedNodeAddr(nicAddr) + nicLinkAddr := linkAddr0 + remoteLinkAddr0 := linkAddr1 + remoteLinkAddr1 := linkAddr2 + + tests := []struct { + name string + nsOpts header.NDPOptionsSerializer + nsSrcLinkAddr tcpip.LinkAddress + nsSrc tcpip.Address + nsDst tcpip.Address + nsInvalid bool + naDstLinkAddr tcpip.LinkAddress + naSolicited bool + naSrc tcpip.Address + naDst tcpip.Address + }{ + { + name: "Unspecified source to multicast destination", + nsOpts: nil, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: header.IPv6Any, + nsDst: nicAddrSNMC, + nsInvalid: false, + naDstLinkAddr: remoteLinkAddr0, + naSolicited: false, + naSrc: nicAddr, + naDst: header.IPv6AllNodesMulticastAddress, + }, + { + name: "Unspecified source with source ll option to multicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr0[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: header.IPv6Any, + nsDst: nicAddrSNMC, + nsInvalid: true, + }, + { + name: "Unspecified source to unicast destination", + nsOpts: nil, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: header.IPv6Any, + nsDst: nicAddr, + nsInvalid: false, + naDstLinkAddr: remoteLinkAddr0, + naSolicited: false, + naSrc: nicAddr, + naDst: header.IPv6AllNodesMulticastAddress, + }, + { + name: "Unspecified source with source ll option to unicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr0[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: header.IPv6Any, + nsDst: nicAddr, + nsInvalid: true, + }, + + { + name: "Specified source with 1 source ll to multicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr0[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddrSNMC, + nsInvalid: false, + naDstLinkAddr: remoteLinkAddr0, + naSolicited: true, + naSrc: nicAddr, + naDst: remoteAddr, + }, + { + name: "Specified source with 1 source ll different from route to multicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr1[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddrSNMC, + nsInvalid: false, + naDstLinkAddr: remoteLinkAddr1, + naSolicited: true, + naSrc: nicAddr, + naDst: remoteAddr, + }, + { + name: "Specified source to multicast destination", + nsOpts: nil, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddrSNMC, + nsInvalid: true, + }, + { + name: "Specified source with 2 source ll to multicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr0[:]), + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr1[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddrSNMC, + nsInvalid: true, + }, + + { + name: "Specified source to unicast destination", + nsOpts: nil, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddr, + nsInvalid: false, + naDstLinkAddr: remoteLinkAddr0, + naSolicited: true, + naSrc: nicAddr, + naDst: remoteAddr, + }, + { + name: "Specified source with 1 source ll to unicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr0[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddr, + nsInvalid: false, + naDstLinkAddr: remoteLinkAddr0, + naSolicited: true, + naSrc: nicAddr, + naDst: remoteAddr, + }, + { + name: "Specified source with 1 source ll different from route to unicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr1[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddr, + nsInvalid: false, + naDstLinkAddr: remoteLinkAddr1, + naSolicited: true, + naSrc: nicAddr, + naDst: remoteAddr, + }, + { + name: "Specified source with 2 source ll to unicast destination", + nsOpts: header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr0[:]), + header.NDPSourceLinkLayerAddressOption(remoteLinkAddr1[:]), + }, + nsSrcLinkAddr: remoteLinkAddr0, + nsSrc: remoteAddr, + nsDst: nicAddr, + nsInvalid: true, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{NewProtocol()}, + }) + e := channel.New(1, 1280, nicLinkAddr) + if err := s.CreateNIC(nicID, e); err != nil { + t.Fatalf("CreateNIC(%d, _) = %s", nicID, err) + } + if err := s.AddAddress(nicID, ProtocolNumber, nicAddr); err != nil { + t.Fatalf("AddAddress(%d, %d, %s) = %s", nicID, ProtocolNumber, nicAddr, err) + } + + ndpNSSize := header.ICMPv6NeighborSolicitMinimumSize + test.nsOpts.Length() + hdr := buffer.NewPrependable(header.IPv6MinimumSize + ndpNSSize) + pkt := header.ICMPv6(hdr.Prepend(ndpNSSize)) + pkt.SetType(header.ICMPv6NeighborSolicit) + ns := header.NDPNeighborSolicit(pkt.NDPPayload()) + ns.SetTargetAddress(nicAddr) + opts := ns.Options() + opts.Serialize(test.nsOpts) + pkt.SetChecksum(header.ICMPv6Checksum(pkt, test.nsSrc, test.nsDst, buffer.VectorisedView{})) + payloadLength := hdr.UsedLength() + ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) + ip.Encode(&header.IPv6Fields{ + PayloadLength: uint16(payloadLength), + NextHeader: uint8(header.ICMPv6ProtocolNumber), + HopLimit: 255, + SrcAddr: test.nsSrc, + DstAddr: test.nsDst, + }) + + invalid := s.Stats().ICMP.V6PacketsReceived.Invalid + + // Invalid count should initially be 0. + if got := invalid.Value(); got != 0 { + t.Fatalf("got invalid = %d, want = 0", got) + } + + e.InjectLinkAddr(ProtocolNumber, test.nsSrcLinkAddr, stack.PacketBuffer{ + Data: hdr.View().ToVectorisedView(), + }) + + if test.nsInvalid { + if got := invalid.Value(); got != 1 { + t.Fatalf("got invalid = %d, want = 1", got) + } + + if p, got := e.Read(); got { + t.Fatalf("unexpected response to an invalid NS = %+v", p.Pkt) + } + + // If we expected the NS to be invalid, we have nothing else to check. + return + } + + if got := invalid.Value(); got != 0 { + t.Fatalf("got invalid = %d, want = 0", got) + } + + p, got := e.Read() + if !got { + t.Fatal("expected an NDP NA response") + } + + if p.Route.RemoteLinkAddress != test.naDstLinkAddr { + t.Errorf("got p.Route.RemoteLinkAddress = %s, want = %s", p.Route.RemoteLinkAddress, test.naDstLinkAddr) + } + + checker.IPv6(t, p.Pkt.Header.View(), + checker.SrcAddr(test.naSrc), + checker.DstAddr(test.naDst), + checker.TTL(header.NDPHopLimit), + checker.NDPNA( + checker.NDPNASolicitedFlag(test.naSolicited), + checker.NDPNATargetAddress(nicAddr), + checker.NDPNAOptions([]header.NDPOption{ + header.NDPTargetLinkLayerAddressOption(nicLinkAddr[:]), + }), + )) + }) + } +} + // TestNeighorAdvertisementWithTargetLinkLayerOption tests that receiving a // valid NDP NA message with the Target Link Layer Address option results in a // new entry in the link address cache for the target of the message. |