From 2a2da5be31ea3c32e66f0c0ff61ef189848f5258 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Mon, 27 Jan 2020 20:28:14 -0800 Subject: Add a type to represent the NDP Source Link Layer Address option Tests: - header.TestNDPSourceLinkLayerAddressOptionEthernetAddress - header.TestNDPSourceLinkLayerAddressOptionSerialize - header.TestNDPOptionsIterCheck - header.TestNDPOptionsIter PiperOrigin-RevId: 291856429 --- pkg/tcpip/header/icmpv6.go | 2 +- pkg/tcpip/header/ndp_options.go | 52 ++++++++++-- pkg/tcpip/header/ndp_test.go | 180 ++++++++++++++++++++++++++++++++++++---- 3 files changed, 214 insertions(+), 20 deletions(-) diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go index b4037b6c8..b095dc0ab 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 + ndpTargetEthernetLinkLayerAddressSize + 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 06e0bace2..1e60f3d4f 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -24,13 +24,17 @@ import ( ) const ( - // NDPTargetLinkLayerAddressOptionType is the type of the Target - // Link-Layer Address option, as per RFC 4861 section 4.6.1. + // NDPSourceLinkLayerAddressOptionType is the type of the Source Link Layer + // Address option, as per RFC 4861 section 4.6.1. + NDPSourceLinkLayerAddressOptionType = 1 + + // NDPTargetLinkLayerAddressOptionType is the type of the Target Link Layer + // Address option, as per RFC 4861 section 4.6.1. NDPTargetLinkLayerAddressOptionType = 2 - // ndpTargetEthernetLinkLayerAddressSize is the size of a Target - // Link Layer Option for an Ethernet address. - ndpTargetEthernetLinkLayerAddressSize = 8 + // ndpLinkLayerAddressSize is the size of a Source or Target Link Layer + // Address option. + ndpLinkLayerAddressSize = 8 // NDPPrefixInformationType is the type of the Prefix Information // option, as per RFC 4861 section 4.6.2. @@ -189,6 +193,9 @@ func (i *NDPOptionIterator) Next() (NDPOption, bool, error) { i.opts = i.opts[numBytes:] switch t { + case NDPSourceLinkLayerAddressOptionType: + return NDPSourceLinkLayerAddressOption(body), false, nil + case NDPTargetLinkLayerAddressOptionType: return NDPTargetLinkLayerAddressOption(body), false, nil @@ -368,6 +375,41 @@ func (b NDPOptionsSerializer) Length() int { return l } +// NDPSourceLinkLayerAddressOption is the NDP Source Link Layer Option +// as defined by RFC 4861 section 4.6.1. +// +// It is the first X bytes following the NDP option's Type and Length field +// where X is the value in Length multiplied by lengthByteUnits - 2 bytes. +type NDPSourceLinkLayerAddressOption tcpip.LinkAddress + +// Type implements NDPOption.Type. +func (o NDPSourceLinkLayerAddressOption) Type() uint8 { + return NDPSourceLinkLayerAddressOptionType +} + +// Length implements NDPOption.Length. +func (o NDPSourceLinkLayerAddressOption) Length() int { + return len(o) +} + +// serializeInto implements NDPOption.serializeInto. +func (o NDPSourceLinkLayerAddressOption) serializeInto(b []byte) int { + return copy(b, 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 +// EthernetAddressSize bytes are returned as that is all that is needed for an +// Ethernet address. +func (o NDPSourceLinkLayerAddressOption) EthernetAddress() tcpip.LinkAddress { + if len(o) >= EthernetAddressSize { + return tcpip.LinkAddress(o[:EthernetAddressSize]) + } + + return tcpip.LinkAddress([]byte(nil)) +} + // NDPTargetLinkLayerAddressOption is the NDP Target Link Layer Option // as defined by RFC 4861 section 4.6.1. // diff --git a/pkg/tcpip/header/ndp_test.go b/pkg/tcpip/header/ndp_test.go index 2c439d70c..1cb9f5dc8 100644 --- a/pkg/tcpip/header/ndp_test.go +++ b/pkg/tcpip/header/ndp_test.go @@ -153,6 +153,125 @@ func TestNDPRouterAdvert(t *testing.T) { } } +// TestNDPSourceLinkLayerAddressOptionEthernetAddress tests getting the +// Ethernet address from an NDPSourceLinkLayerAddressOption. +func TestNDPSourceLinkLayerAddressOptionEthernetAddress(t *testing.T) { + tests := []struct { + name string + buf []byte + expected tcpip.LinkAddress + }{ + { + "ValidMAC", + []byte{1, 2, 3, 4, 5, 6}, + tcpip.LinkAddress("\x01\x02\x03\x04\x05\x06"), + }, + { + "SLLBodyTooShort", + []byte{1, 2, 3, 4, 5}, + tcpip.LinkAddress([]byte(nil)), + }, + { + "SLLBodyLargerThanNeeded", + []byte{1, 2, 3, 4, 5, 6, 7, 8}, + tcpip.LinkAddress("\x01\x02\x03\x04\x05\x06"), + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + sll := NDPSourceLinkLayerAddressOption(test.buf) + if got := sll.EthernetAddress(); got != test.expected { + t.Errorf("got sll.EthernetAddress = %s, want = %s", got, test.expected) + } + }) + } +} + +// TestNDPSourceLinkLayerAddressOptionSerialize tests serializing a +// NDPSourceLinkLayerAddressOption. +func TestNDPSourceLinkLayerAddressOptionSerialize(t *testing.T) { + tests := []struct { + name string + buf []byte + expectedBuf []byte + addr tcpip.LinkAddress + }{ + { + "Ethernet", + make([]byte, 8), + []byte{1, 1, 1, 2, 3, 4, 5, 6}, + "\x01\x02\x03\x04\x05\x06", + }, + { + "Padding", + []byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, + []byte{1, 2, 1, 2, 3, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0}, + "\x01\x02\x03\x04\x05\x06\x07\x08", + }, + { + "Empty", + nil, + nil, + "", + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + opts := NDPOptions(test.buf) + serializer := NDPOptionsSerializer{ + NDPSourceLinkLayerAddressOption(test.addr), + } + if got, want := int(serializer.Length()), len(test.expectedBuf); got != want { + t.Fatalf("got Length = %d, want = %d", got, want) + } + opts.Serialize(serializer) + if !bytes.Equal(test.buf, test.expectedBuf) { + t.Fatalf("got b = %d, want = %d", test.buf, test.expectedBuf) + } + + it, err := opts.Iter(true) + if err != nil { + t.Fatalf("got Iter = (_, %s), want = (_, nil)", err) + } + + if len(test.expectedBuf) > 0 { + next, done, err := it.Next() + if err != nil { + t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if done { + t.Fatal("got Next = (_, true, _), want = (_, false, _)") + } + if got := next.Type(); got != NDPSourceLinkLayerAddressOptionType { + t.Fatalf("got Type = %d, want = %d", got, NDPSourceLinkLayerAddressOptionType) + } + sll := next.(NDPSourceLinkLayerAddressOption) + if got, want := []byte(sll), test.expectedBuf[2:]; !bytes.Equal(got, want) { + t.Fatalf("got Next = (%x, _, _), want = (%x, _, _)", got, want) + } + + if got, want := sll.EthernetAddress(), tcpip.LinkAddress(test.expectedBuf[2:][:EthernetAddressSize]); got != want { + t.Errorf("got sll.EthernetAddress = %s, want = %s", got, want) + } + } + + // Iterator should not return anything else. + next, done, err := it.Next() + if err != nil { + t.Errorf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if !done { + t.Error("got Next = (_, false, _), want = (_, true, _)") + } + if next != nil { + t.Errorf("got Next = (%x, _, _), want = (nil, _, _)", next) + } + }) + } +} + // TestNDPTargetLinkLayerAddressOptionEthernetAddress tests getting the // Ethernet address from an NDPTargetLinkLayerAddressOption. func TestNDPTargetLinkLayerAddressOptionEthernetAddress(t *testing.T) { @@ -186,7 +305,6 @@ func TestNDPTargetLinkLayerAddressOptionEthernetAddress(t *testing.T) { } }) } - } // TestNDPTargetLinkLayerAddressOptionSerialize tests serializing a @@ -212,8 +330,8 @@ func TestNDPTargetLinkLayerAddressOptionSerialize(t *testing.T) { }, { "Empty", - []byte{}, - []byte{}, + nil, + nil, "", }, } @@ -246,7 +364,7 @@ func TestNDPTargetLinkLayerAddressOptionSerialize(t *testing.T) { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } if got := next.Type(); got != NDPTargetLinkLayerAddressOptionType { - t.Fatalf("got Type %= %d, want = %d", got, NDPTargetLinkLayerAddressOptionType) + t.Fatalf("got Type = %d, want = %d", got, NDPTargetLinkLayerAddressOptionType) } tll := next.(NDPTargetLinkLayerAddressOption) if got, want := []byte(tll), test.expectedBuf[2:]; !bytes.Equal(got, want) { @@ -254,7 +372,7 @@ func TestNDPTargetLinkLayerAddressOptionSerialize(t *testing.T) { } if got, want := tll.EthernetAddress(), tcpip.LinkAddress(test.expectedBuf[2:][:EthernetAddressSize]); got != want { - t.Errorf("got tll.MACAddress = %s, want = %s", got, want) + t.Errorf("got tll.EthernetAddress = %s, want = %s", got, want) } } @@ -510,7 +628,7 @@ func TestNDPRecursiveDNSServerOption(t *testing.T) { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } if got := next.Type(); got != NDPRecursiveDNSServerOptionType { - t.Fatalf("got Type %= %d, want = %d", got, NDPRecursiveDNSServerOptionType) + t.Fatalf("got Type = %d, want = %d", got, NDPRecursiveDNSServerOptionType) } opt, ok := next.(NDPRecursiveDNSServer) @@ -552,6 +670,16 @@ func TestNDPOptionsIterCheck(t *testing.T) { []byte{0, 0, 0, 0, 0, 0, 0, 0}, ErrNDPOptZeroLength, }, + { + "ValidSourceLinkLayerAddressOption", + []byte{1, 1, 1, 2, 3, 4, 5, 6}, + nil, + }, + { + "TooSmallSourceLinkLayerAddressOption", + []byte{1, 1, 1, 2, 3, 4, 5}, + ErrNDPOptBufExhausted, + }, { "ValidTargetLinkLayerAddressOption", []byte{2, 1, 1, 2, 3, 4, 5, 6}, @@ -603,10 +731,13 @@ func TestNDPOptionsIterCheck(t *testing.T) { ErrNDPOptMalformedBody, }, { - "ValidTargetLinkLayerAddressWithPrefixInformation", + "ValidSourceAndTargetLinkLayerAddressWithPrefixInformation", []byte{ + // Source Link-Layer Address. + 1, 1, 1, 2, 3, 4, 5, 6, + // Target Link-Layer Address. - 2, 1, 1, 2, 3, 4, 5, 6, + 2, 1, 7, 8, 9, 10, 11, 12, // Prefix information. 3, 4, 43, 64, @@ -621,10 +752,13 @@ func TestNDPOptionsIterCheck(t *testing.T) { nil, }, { - "ValidTargetLinkLayerAddressWithPrefixInformationWithUnrecognized", + "ValidSourceAndTargetLinkLayerAddressWithPrefixInformationWithUnrecognized", []byte{ + // Source Link-Layer Address. + 1, 1, 1, 2, 3, 4, 5, 6, + // Target Link-Layer Address. - 2, 1, 1, 2, 3, 4, 5, 6, + 2, 1, 7, 8, 9, 10, 11, 12, // 255 is an unrecognized type. If 255 ends up // being the type for some recognized type, @@ -714,8 +848,11 @@ func TestNDPOptionsIterCheck(t *testing.T) { // here. func TestNDPOptionsIter(t *testing.T) { buf := []byte{ + // Source Link-Layer Address. + 1, 1, 1, 2, 3, 4, 5, 6, + // Target Link-Layer Address. - 2, 1, 1, 2, 3, 4, 5, 6, + 2, 1, 7, 8, 9, 10, 11, 12, // 255 is an unrecognized type. If 255 ends up being the type // for some recognized type, update 255 to some other @@ -740,7 +877,7 @@ func TestNDPOptionsIter(t *testing.T) { t.Fatalf("got Iter = (_, %s), want = (_, nil)", err) } - // Test the first (Taret Link-Layer) option. + // Test the first (Source Link-Layer) option. next, done, err := it.Next() if err != nil { t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) @@ -748,7 +885,22 @@ func TestNDPOptionsIter(t *testing.T) { if done { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } - if got, want := []byte(next.(NDPTargetLinkLayerAddressOption)), buf[2:][:6]; !bytes.Equal(got, want) { + if got, want := []byte(next.(NDPSourceLinkLayerAddressOption)), buf[2:][:6]; !bytes.Equal(got, want) { + t.Errorf("got Next = (%x, _, _), want = (%x, _, _)", got, want) + } + if got := next.Type(); got != NDPSourceLinkLayerAddressOptionType { + t.Errorf("got Type = %d, want = %d", got, NDPSourceLinkLayerAddressOptionType) + } + + // Test the next (Target Link-Layer) option. + next, done, err = it.Next() + if err != nil { + t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if done { + t.Fatal("got Next = (_, true, _), want = (_, false, _)") + } + if got, want := []byte(next.(NDPTargetLinkLayerAddressOption)), buf[10:][:6]; !bytes.Equal(got, want) { t.Errorf("got Next = (%x, _, _), want = (%x, _, _)", got, want) } if got := next.Type(); got != NDPTargetLinkLayerAddressOptionType { @@ -764,7 +916,7 @@ func TestNDPOptionsIter(t *testing.T) { if done { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } - if got, want := next.(NDPPrefixInformation), buf[26:][:30]; !bytes.Equal(got, want) { + if got, want := next.(NDPPrefixInformation), buf[34:][:30]; !bytes.Equal(got, want) { t.Errorf("got Next = (%x, _, _), want = (%x, _, _)", got, want) } if got := next.Type(); got != NDPPrefixInformationType { -- cgit v1.2.3