From ce0bac4be9d808877248c328fac07ff0d66b9607 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Tue, 28 Jan 2020 13:37:10 -0800 Subject: Include the NDP Source Link Layer option when sending DAD messages Test: stack_test.TestDADResolve PiperOrigin-RevId: 292003124 --- pkg/tcpip/checker/checker.go | 50 +++++++++++++++++++++++++++++++++++++++++ pkg/tcpip/header/icmpv6.go | 2 +- pkg/tcpip/header/ndp_options.go | 35 ++++++++++++++++++++++++++--- pkg/tcpip/stack/ndp.go | 22 ++++++++++++++++-- pkg/tcpip/stack/ndp_test.go | 6 ++++- 5 files changed, 108 insertions(+), 7 deletions(-) (limited to 'pkg/tcpip') diff --git a/pkg/tcpip/checker/checker.go b/pkg/tcpip/checker/checker.go index 885d773b0..4d6ae0871 100644 --- a/pkg/tcpip/checker/checker.go +++ b/pkg/tcpip/checker/checker.go @@ -771,6 +771,56 @@ func NDPNSTargetAddress(want tcpip.Address) TransportChecker { } } +// NDPNSOptions 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 NDPNS message as far as the size is concerned. +func NDPNSOptions(opts []header.NDPOption) TransportChecker { + return func(t *testing.T, h header.Transport) { + t.Helper() + + icmp := h.(header.ICMPv6) + ns := header.NDPNeighborSolicit(icmp.NDPPayload()) + it, err := ns.Options().Iter(true) + if err != nil { + t.Errorf("opts.Iter(true): %s", err) + return + } + + i := 0 + for { + opt, done, _ := it.Next() + if done { + break + } + + if i >= len(opts) { + t.Errorf("got unexpected option: %s", opt) + continue + } + + switch wantOpt := opts[i].(type) { + case header.NDPSourceLinkLayerAddressOption: + gotOpt, ok := opt.(header.NDPSourceLinkLayerAddressOption) + 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: + panic("not implemented") + } + + i++ + } + + if missing := opts[i:]; len(missing) > 0 { + t.Errorf("missing options: %s", missing) + } + } +} + // NDPRS creates a checker that checks that the packet contains a valid NDP // Router Solicitation message (as per the raw wire format). func NDPRS() NetworkChecker { diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go index b095dc0ab..c7ee2de57 100644 --- a/pkg/tcpip/header/icmpv6.go +++ b/pkg/tcpip/header/icmpv6.go @@ -52,7 +52,7 @@ const ( // ICMPv6NeighborAdvertSize is size of a neighbor advertisement // including the NDP Target Link Layer option for an Ethernet // address. - ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + ndpLinkLayerAddressSize + ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + NDPLinkLayerAddressSize // ICMPv6EchoMinimumSize is the minimum size of a valid ICMP echo packet. ICMPv6EchoMinimumSize = 8 diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 1e60f3d4f..e6a6ad39b 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -17,6 +17,7 @@ package header import ( "encoding/binary" "errors" + "fmt" "math" "time" @@ -32,9 +33,9 @@ const ( // Address option, as per RFC 4861 section 4.6.1. NDPTargetLinkLayerAddressOptionType = 2 - // ndpLinkLayerAddressSize is the size of a Source or Target Link Layer - // Address option. - ndpLinkLayerAddressSize = 8 + // NDPLinkLayerAddressSize is the size of a Source or Target Link Layer + // Address option for an Ethernet address. + NDPLinkLayerAddressSize = 8 // NDPPrefixInformationType is the type of the Prefix Information // option, as per RFC 4861 section 4.6.2. @@ -300,6 +301,8 @@ func (b NDPOptions) Serialize(s NDPOptionsSerializer) int { // NDPOption is the set of functions to be implemented by all NDP option types. type NDPOption interface { + fmt.Stringer + // Type returns the type of the receiver. Type() uint8 @@ -397,6 +400,11 @@ func (o NDPSourceLinkLayerAddressOption) serializeInto(b []byte) int { return copy(b, o) } +// String implements fmt.Stringer.String. +func (o NDPSourceLinkLayerAddressOption) String() string { + return fmt.Sprintf("%T(%s)", o, tcpip.LinkAddress(o)) +} + // EthernetAddress will return an ethernet (MAC) address if the // NDPSourceLinkLayerAddressOption's body has at minimum EthernetAddressSize // bytes. If the body has more than EthernetAddressSize bytes, only the first @@ -432,6 +440,11 @@ func (o NDPTargetLinkLayerAddressOption) serializeInto(b []byte) int { return copy(b, o) } +// String implements fmt.Stringer.String. +func (o NDPTargetLinkLayerAddressOption) String() string { + return fmt.Sprintf("%T(%s)", o, tcpip.LinkAddress(o)) +} + // EthernetAddress will return an ethernet (MAC) address if the // NDPTargetLinkLayerAddressOption's body has at minimum EthernetAddressSize // bytes. If the body has more than EthernetAddressSize bytes, only the first @@ -478,6 +491,17 @@ func (o NDPPrefixInformation) serializeInto(b []byte) int { return used } +// String implements fmt.Stringer.String. +func (o NDPPrefixInformation) String() string { + return fmt.Sprintf("%T(O=%t, A=%t, PL=%s, VL=%s, Prefix=%s)", + o, + o.OnLinkFlag(), + o.AutonomousAddressConfigurationFlag(), + o.PreferredLifetime(), + o.ValidLifetime(), + o.Subnet()) +} + // PrefixLength returns the value in the number of leading bits in the Prefix // that are valid. // @@ -587,6 +611,11 @@ func (o NDPRecursiveDNSServer) serializeInto(b []byte) int { return used } +// String implements fmt.Stringer.String. +func (o NDPRecursiveDNSServer) String() string { + return fmt.Sprintf("%T(%s valid for %s)", o, o.Addresses(), o.Lifetime()) +} + // Lifetime returns the length of time that the DNS server addresses // in this option may be used for name resolution. // diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index d983ac390..245694118 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -538,11 +538,29 @@ func (ndp *ndpState) sendDADPacket(addr tcpip.Address) *tcpip.Error { r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, snmc, ndp.nic.linkEP.LinkAddress(), ref, false, false) defer r.Release() - hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6NeighborSolicitMinimumSize) - pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborSolicitMinimumSize)) + linkAddr := ndp.nic.linkEP.LinkAddress() + isValidLinkAddr := header.IsValidUnicastEthernetAddress(linkAddr) + ndpNSSize := header.ICMPv6NeighborSolicitMinimumSize + if isValidLinkAddr { + // Only include a Source Link Layer Address option if the NIC has a valid + // link layer address. + // + // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by + // LinkEndpoint.LinkAddress) before reaching this point. + ndpNSSize += header.NDPLinkLayerAddressSize + } + + hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + ndpNSSize) + pkt := header.ICMPv6(hdr.Prepend(ndpNSSize)) pkt.SetType(header.ICMPv6NeighborSolicit) ns := header.NDPNeighborSolicit(pkt.NDPPayload()) ns.SetTargetAddress(addr) + + if isValidLinkAddr { + ns.Options().Serialize(header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(linkAddr), + }) + } pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) sent := r.Stats().ICMP.V6PacketsSent diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index ad2c6f601..726468e41 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -417,7 +417,11 @@ func TestDADResolve(t *testing.T) { checker.IPv6(t, p.Pkt.Header.View().ToVectorisedView().First(), checker.TTL(header.NDPHopLimit), checker.NDPNS( - checker.NDPNSTargetAddress(addr1))) + checker.NDPNSTargetAddress(addr1), + checker.NDPNSOptions([]header.NDPOption{ + header.NDPSourceLinkLayerAddressOption(linkAddr1), + }), + )) } }) } -- cgit v1.2.3