From fd28ccfaa48a6b4c15aedb2bdd490211589c42d7 Mon Sep 17 00:00:00 2001 From: Bruno Dal Bo Date: Fri, 4 Dec 2020 10:08:50 -0800 Subject: Introduce IPv4 options serializer and add RouterAlert to IGMP PiperOrigin-RevId: 345701623 --- pkg/tcpip/checker/checker.go | 36 ++++++ pkg/tcpip/header/BUILD | 1 + pkg/tcpip/header/ipv4.go | 206 ++++++++++++++++++++++++++---- pkg/tcpip/header/ipv4_test.go | 179 ++++++++++++++++++++++++++ pkg/tcpip/header/ndp_options.go | 2 +- pkg/tcpip/network/ip_test.go | 26 +++- pkg/tcpip/network/ipv4/igmp.go | 4 +- pkg/tcpip/network/ipv4/igmp_test.go | 3 + pkg/tcpip/network/ipv4/ipv4.go | 31 ++--- pkg/tcpip/network/ipv4/ipv4_test.go | 133 +++---------------- pkg/tcpip/network/multicast_group_test.go | 1 + pkg/tcpip/stack/registration.go | 13 -- test/packetimpact/testbench/layers.go | 39 +++--- 13 files changed, 474 insertions(+), 200 deletions(-) create mode 100644 pkg/tcpip/header/ipv4_test.go diff --git a/pkg/tcpip/checker/checker.go b/pkg/tcpip/checker/checker.go index e669397dd..d3ae56ac6 100644 --- a/pkg/tcpip/checker/checker.go +++ b/pkg/tcpip/checker/checker.go @@ -217,6 +217,42 @@ func IPv4Options(want header.IPv4Options) NetworkChecker { } } +// IPv4RouterAlert returns a checker that checks that the RouterAlert option is +// set in an IPv4 packet. +func IPv4RouterAlert() NetworkChecker { + return func(t *testing.T, h []header.Network) { + t.Helper() + ip, ok := h[0].(header.IPv4) + if !ok { + t.Fatalf("unexpected network header passed to checker, got = %T, want = header.IPv4", h[0]) + } + iterator := ip.Options().MakeIterator() + for { + opt, done, err := iterator.Next() + if err != nil { + t.Fatalf("error acquiring next IPv4 option %s", err) + } + if done { + break + } + if opt.Type() != header.IPv4OptionRouterAlertType { + continue + } + want := [header.IPv4OptionRouterAlertLength]byte{ + byte(header.IPv4OptionRouterAlertType), + header.IPv4OptionRouterAlertLength, + header.IPv4OptionRouterAlertValue, + header.IPv4OptionRouterAlertValue, + } + if diff := cmp.Diff(want[:], opt.Contents()); diff != "" { + t.Errorf("router alert option mismatch (-want +got):\n%s", diff) + } + return + } + t.Errorf("failed to find router alert option in %v", ip.Options()) + } +} + // FragmentOffset creates a checker that checks the FragmentOffset field. func FragmentOffset(offset uint16) NetworkChecker { return func(t *testing.T, h []header.Network) { diff --git a/pkg/tcpip/header/BUILD b/pkg/tcpip/header/BUILD index 144093c3a..0bdc12d53 100644 --- a/pkg/tcpip/header/BUILD +++ b/pkg/tcpip/header/BUILD @@ -42,6 +42,7 @@ go_test( srcs = [ "checksum_test.go", "igmp_test.go", + "ipv4_test.go", "ipv6_test.go", "ipversion_test.go", "tcp_test.go", diff --git a/pkg/tcpip/header/ipv4.go b/pkg/tcpip/header/ipv4.go index 5fddd2af6..e6103f4bc 100644 --- a/pkg/tcpip/header/ipv4.go +++ b/pkg/tcpip/header/ipv4.go @@ -100,7 +100,7 @@ type IPv4Fields struct { // // That leaves ten 32 bit (4 byte) fields for options. An attempt to encode // more will fail. - Options IPv4Options + Options IPv4OptionsSerializer } // IPv4 is an IPv4 header. @@ -285,18 +285,17 @@ func (b IPv4) DestinationAddress() tcpip.Address { return tcpip.Address(b[dstAddr : dstAddr+IPv4AddressSize]) } -// IPv4Options is a buffer that holds all the raw IP options. -type IPv4Options []byte - -// SizeWithPadding implements stack.NetOptions. -// It reports the size to allocate for the Options. RFC 791 page 23 (end of -// section 3.1) says of the padding at the end of the options: +// padIPv4OptionsLength returns the total length for IPv4 options of length l +// after applying padding according to RFC 791: // The internet header padding is used to ensure that the internet // header ends on a 32 bit boundary. -func (o IPv4Options) SizeWithPadding() int { - return (len(o) + IPv4IHLStride - 1) & ^(IPv4IHLStride - 1) +func padIPv4OptionsLength(length uint8) uint8 { + return (length + IPv4IHLStride - 1) & ^uint8(IPv4IHLStride-1) } +// IPv4Options is a buffer that holds all the raw IP options. +type IPv4Options []byte + // Options returns a buffer holding the options. func (b IPv4) Options() IPv4Options { hdrLen := b.HeaderLength() @@ -375,26 +374,16 @@ func (b IPv4) CalculateChecksum() uint16 { func (b IPv4) Encode(i *IPv4Fields) { // The size of the options defines the size of the whole header and thus the // IHL field. Options are rare and this is a heavily used function so it is - // worth a bit of optimisation here to keep the copy out of the fast path. - hdrLen := IPv4MinimumSize + // worth a bit of optimisation here to keep the serializer out of the fast + // path. + hdrLen := uint8(IPv4MinimumSize) if len(i.Options) != 0 { - // SizeWithPadding is always >= len(i.Options). - aLen := i.Options.SizeWithPadding() - hdrLen += aLen - if hdrLen > len(b) { - panic(fmt.Sprintf("encode received %d bytes, wanted >= %d", len(b), hdrLen)) - } - opts := b[options:] - // This avoids bounds checks on the next line(s) which would happen even - // if there's no work to do. - if n := copy(opts, i.Options); n != aLen { - padding := opts[n:][:aLen-n] - for i := range padding { - padding[i] = 0 - } - } + hdrLen += i.Options.Serialize(b[options:]) } - b.SetHeaderLength(uint8(hdrLen)) + if hdrLen > IPv4MaximumHeaderSize { + panic(fmt.Sprintf("%d is larger than maximum IPv4 header size of %d", hdrLen, IPv4MaximumHeaderSize)) + } + b.SetHeaderLength(hdrLen) b[tos] = i.TOS b.SetTotalLength(i.TotalLength) binary.BigEndian.PutUint16(b[id:], i.ID) @@ -474,6 +463,10 @@ const ( // options and may appear multiple times. IPv4OptionNOPType IPv4OptionType = 1 + // IPv4OptionRouterAlertType is the option type for the Router Alert option, + // defined in RFC 2113 Section 2.1. + IPv4OptionRouterAlertType IPv4OptionType = 20 | 0x80 + // IPv4OptionRecordRouteType is used by each router on the path of the packet // to record its path. It is carried over to an Echo Reply. IPv4OptionRecordRouteType IPv4OptionType = 7 @@ -874,3 +867,162 @@ func (rr *IPv4OptionRecordRoute) Size() uint8 { return uint8(len(*rr)) } // Contents implements IPv4Option. func (rr *IPv4OptionRecordRoute) Contents() []byte { return []byte(*rr) } + +// Router Alert option specific related constants. +// +// from RFC 2113 section 2.1: +// +// +--------+--------+--------+--------+ +// |10010100|00000100| 2 octet value | +// +--------+--------+--------+--------+ +// +// Type: +// Copied flag: 1 (all fragments must carry the option) +// Option class: 0 (control) +// Option number: 20 (decimal) +// +// Length: 4 +// +// Value: A two octet code with the following values: +// 0 - Router shall examine packet +// 1-65535 - Reserved +const ( + // IPv4OptionRouterAlertLength is the length of a Router Alert option. + IPv4OptionRouterAlertLength = 4 + + // IPv4OptionRouterAlertValue is the only permissible value of the 16 bit + // payload of the router alert option. + IPv4OptionRouterAlertValue = 0 + + // iPv4OptionRouterAlertValueOffset is the offset for the value of a + // RouterAlert option. + iPv4OptionRouterAlertValueOffset = 2 +) + +// IPv4SerializableOption is an interface to represent serializable IPv4 option +// types. +type IPv4SerializableOption interface { + // optionType returns the type identifier of the option. + optionType() IPv4OptionType +} + +// IPv4SerializableOptionPayload is an interface providing serialization of the +// payload of an IPv4 option. +type IPv4SerializableOptionPayload interface { + // length returns the size of the payload. + length() uint8 + + // serializeInto serializes the payload into the provided byte buffer. + // + // Note, the caller MUST provide a byte buffer with size of at least + // Length. Implementers of this function may assume that the byte buffer + // is of sufficient size. serializeInto MUST panic if the provided byte + // buffer is not of sufficient size. + // + // serializeInto will return the number of bytes that was used to + // serialize the receiver. Implementers must only use the number of + // bytes required to serialize the receiver. Callers MAY provide a + // larger buffer than required to serialize into. + serializeInto(buffer []byte) uint8 +} + +// IPv4OptionsSerializer is a serializer for IPv4 options. +type IPv4OptionsSerializer []IPv4SerializableOption + +// Length returns the total number of bytes required to serialize the options. +func (s IPv4OptionsSerializer) Length() uint8 { + var total uint8 + for _, opt := range s { + total++ + if withPayload, ok := opt.(IPv4SerializableOptionPayload); ok { + // Add 1 to reported length to account for the length byte. + total += 1 + withPayload.length() + } + } + return padIPv4OptionsLength(total) +} + +// Serialize serializes the provided list of IPV4 options into b. +// +// Note, b must be of sufficient size to hold all the options in s. See +// IPv4OptionsSerializer.Length for details on the getting the total size +// of a serialized IPv4OptionsSerializer. +// +// Serialize panics if b is not of sufficient size to hold all the options in s. +func (s IPv4OptionsSerializer) Serialize(b []byte) uint8 { + var total uint8 + for _, opt := range s { + ty := opt.optionType() + if withPayload, ok := opt.(IPv4SerializableOptionPayload); ok { + // Serialize first to reduce bounds checks. + l := 2 + withPayload.serializeInto(b[2:]) + b[0] = byte(ty) + b[1] = l + b = b[l:] + total += l + continue + } + // Options without payload consist only of the type field. + // + // NB: Repeating code from the branch above is intentional to minimize + // bounds checks. + b[0] = byte(ty) + b = b[1:] + total++ + } + + // According to RFC 791: + // + // The internet header padding is used to ensure that the internet + // header ends on a 32 bit boundary. The padding is zero. + padded := padIPv4OptionsLength(total) + b = b[:padded-total] + for i := range b { + b[i] = 0 + } + return padded +} + +var _ IPv4SerializableOptionPayload = (*IPv4SerializableRouterAlertOption)(nil) +var _ IPv4SerializableOption = (*IPv4SerializableRouterAlertOption)(nil) + +// IPv4SerializableRouterAlertOption provides serialization of the Router Alert +// IPv4 option according to RFC 2113. +type IPv4SerializableRouterAlertOption struct{} + +// Type implements IPv4SerializableOption. +func (*IPv4SerializableRouterAlertOption) optionType() IPv4OptionType { + return IPv4OptionRouterAlertType +} + +// Length implements IPv4SerializableOption. +func (*IPv4SerializableRouterAlertOption) length() uint8 { + return IPv4OptionRouterAlertLength - iPv4OptionRouterAlertValueOffset +} + +// SerializeInto implements IPv4SerializableOption. +func (o *IPv4SerializableRouterAlertOption) serializeInto(buffer []byte) uint8 { + binary.BigEndian.PutUint16(buffer, IPv4OptionRouterAlertValue) + return o.length() +} + +var _ IPv4SerializableOption = (*IPv4SerializableNOPOption)(nil) + +// IPv4SerializableNOPOption provides serialization for the IPv4 no-op option. +type IPv4SerializableNOPOption struct{} + +// Type implements IPv4SerializableOption. +func (*IPv4SerializableNOPOption) optionType() IPv4OptionType { + return IPv4OptionNOPType +} + +var _ IPv4SerializableOption = (*IPv4SerializableListEndOption)(nil) + +// IPv4SerializableListEndOption provides serialization for the IPv4 List End +// option. +type IPv4SerializableListEndOption struct{} + +// Type implements IPv4SerializableOption. +func (*IPv4SerializableListEndOption) optionType() IPv4OptionType { + return IPv4OptionListEndType +} diff --git a/pkg/tcpip/header/ipv4_test.go b/pkg/tcpip/header/ipv4_test.go new file mode 100644 index 000000000..6475cd694 --- /dev/null +++ b/pkg/tcpip/header/ipv4_test.go @@ -0,0 +1,179 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package header_test + +import ( + "testing" + + "github.com/google/go-cmp/cmp" + "gvisor.dev/gvisor/pkg/tcpip/buffer" + "gvisor.dev/gvisor/pkg/tcpip/header" +) + +func TestIPv4OptionsSerializer(t *testing.T) { + optCases := []struct { + name string + option []header.IPv4SerializableOption + expect []byte + }{ + { + name: "NOP", + option: []header.IPv4SerializableOption{ + &header.IPv4SerializableNOPOption{}, + }, + expect: []byte{1, 0, 0, 0}, + }, + { + name: "ListEnd", + option: []header.IPv4SerializableOption{ + &header.IPv4SerializableListEndOption{}, + }, + expect: []byte{0, 0, 0, 0}, + }, + { + name: "RouterAlert", + option: []header.IPv4SerializableOption{ + &header.IPv4SerializableRouterAlertOption{}, + }, + expect: []byte{148, 4, 0, 0}, + }, { + name: "NOP and RouterAlert", + option: []header.IPv4SerializableOption{ + &header.IPv4SerializableNOPOption{}, + &header.IPv4SerializableRouterAlertOption{}, + }, + expect: []byte{1, 148, 4, 0, 0, 0, 0, 0}, + }, + } + + for _, opt := range optCases { + t.Run(opt.name, func(t *testing.T) { + s := header.IPv4OptionsSerializer(opt.option) + l := s.Length() + if got := len(opt.expect); got != int(l) { + t.Fatalf("s.Length() = %d, want = %d", got, l) + } + b := make([]byte, l) + for i := range b { + // Fill the buffer with full bytes to ensure padding is being set + // correctly. + b[i] = 0xFF + } + if serializedLength := s.Serialize(b); serializedLength != l { + t.Fatalf("s.Serialize(_) = %d, want %d", serializedLength, l) + } + if diff := cmp.Diff(opt.expect, b); diff != "" { + t.Errorf("mismatched serialized option (-want +got):\n%s", diff) + } + }) + } +} + +// TestIPv4Encode checks that ipv4.Encode correctly fills out the requested +// fields when options are supplied. +func TestIPv4EncodeOptions(t *testing.T) { + tests := []struct { + name string + numberOfNops int + encodedOptions header.IPv4Options // reply should look like this + wantIHL int + }{ + { + name: "valid no options", + wantIHL: header.IPv4MinimumSize, + }, + { + name: "one byte options", + numberOfNops: 1, + encodedOptions: header.IPv4Options{1, 0, 0, 0}, + wantIHL: header.IPv4MinimumSize + 4, + }, + { + name: "two byte options", + numberOfNops: 2, + encodedOptions: header.IPv4Options{1, 1, 0, 0}, + wantIHL: header.IPv4MinimumSize + 4, + }, + { + name: "three byte options", + numberOfNops: 3, + encodedOptions: header.IPv4Options{1, 1, 1, 0}, + wantIHL: header.IPv4MinimumSize + 4, + }, + { + name: "four byte options", + numberOfNops: 4, + encodedOptions: header.IPv4Options{1, 1, 1, 1}, + wantIHL: header.IPv4MinimumSize + 4, + }, + { + name: "five byte options", + numberOfNops: 5, + encodedOptions: header.IPv4Options{1, 1, 1, 1, 1, 0, 0, 0}, + wantIHL: header.IPv4MinimumSize + 8, + }, + { + name: "thirty nine byte options", + numberOfNops: 39, + encodedOptions: header.IPv4Options{ + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 0, + }, + wantIHL: header.IPv4MinimumSize + 40, + }, + } + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + serializeOpts := header.IPv4OptionsSerializer(make([]header.IPv4SerializableOption, test.numberOfNops)) + for i := range serializeOpts { + serializeOpts[i] = &header.IPv4SerializableNOPOption{} + } + paddedOptionLength := serializeOpts.Length() + ipHeaderLength := int(header.IPv4MinimumSize + paddedOptionLength) + if ipHeaderLength > header.IPv4MaximumHeaderSize { + t.Fatalf("IP header length too large: got = %d, want <= %d ", ipHeaderLength, header.IPv4MaximumHeaderSize) + } + totalLen := uint16(ipHeaderLength) + hdr := buffer.NewPrependable(int(totalLen)) + ip := header.IPv4(hdr.Prepend(ipHeaderLength)) + // To check the padding works, poison the last byte of the options space. + if paddedOptionLength != serializeOpts.Length() { + ip.SetHeaderLength(uint8(ipHeaderLength)) + ip.Options()[paddedOptionLength-1] = 0xff + ip.SetHeaderLength(0) + } + ip.Encode(&header.IPv4Fields{ + Options: serializeOpts, + }) + options := ip.Options() + wantOptions := test.encodedOptions + if got, want := int(ip.HeaderLength()), test.wantIHL; got != want { + t.Errorf("got IHL of %d, want %d", got, want) + } + + // cmp.Diff does not consider nil slices equal to empty slices, but we do. + if len(wantOptions) == 0 && len(options) == 0 { + return + } + + if diff := cmp.Diff(wantOptions, options); diff != "" { + t.Errorf("options mismatch (-want +got):\n%s", diff) + } + }) + } +} diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 5d3975c56..554242f0c 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -298,7 +298,7 @@ func (b NDPOptions) Iter(check bool) (NDPOptionIterator, error) { return it, nil } -// Serialize serializes the provided list of NDP options into o. +// Serialize serializes the provided list of NDP options into b. // // Note, b must be of sufficient size to hold all the options in s. See // NDPOptionsSerializer.Length for details on the getting the total size diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go index 66d6c3f99..a314dd386 100644 --- a/pkg/tcpip/network/ip_test.go +++ b/pkg/tcpip/network/ip_test.go @@ -1089,7 +1089,19 @@ func TestWriteHeaderIncludedPacket(t *testing.T) { dataBuf := [dataLen]byte{1, 2, 3, 4} data := dataBuf[:] - ipv4Options := header.IPv4Options{0, 1, 0, 1} + ipv4Options := header.IPv4OptionsSerializer{ + &header.IPv4SerializableListEndOption{}, + &header.IPv4SerializableNOPOption{}, + &header.IPv4SerializableListEndOption{}, + &header.IPv4SerializableNOPOption{}, + } + + expectOptions := header.IPv4Options{ + byte(header.IPv4OptionListEndType), + byte(header.IPv4OptionNOPType), + byte(header.IPv4OptionListEndType), + byte(header.IPv4OptionNOPType), + } ipv6FragmentExtHdrBuf := [header.IPv6FragmentExtHdrLength]byte{transportProto, 0, 62, 4, 1, 2, 3, 4} ipv6FragmentExtHdr := ipv6FragmentExtHdrBuf[:] @@ -1239,7 +1251,7 @@ func TestWriteHeaderIncludedPacket(t *testing.T) { nicAddr: localIPv4Addr, remoteAddr: remoteIPv4Addr, pktGen: func(t *testing.T, src tcpip.Address) buffer.VectorisedView { - ipHdrLen := header.IPv4MinimumSize + ipv4Options.SizeWithPadding() + ipHdrLen := int(header.IPv4MinimumSize + ipv4Options.Length()) totalLen := ipHdrLen + len(data) hdr := buffer.NewPrependable(totalLen) if n := copy(hdr.Prepend(len(data)), data); n != len(data) { @@ -1262,7 +1274,7 @@ func TestWriteHeaderIncludedPacket(t *testing.T) { netHdr := pkt.NetworkHeader() - hdrLen := header.IPv4MinimumSize + len(ipv4Options) + hdrLen := int(header.IPv4MinimumSize + ipv4Options.Length()) if len(netHdr.View()) != hdrLen { t.Errorf("got len(netHdr.View()) = %d, want = %d", len(netHdr.View()), hdrLen) } @@ -1272,7 +1284,7 @@ func TestWriteHeaderIncludedPacket(t *testing.T) { checker.DstAddr(remoteIPv4Addr), checker.IPv4HeaderLength(hdrLen), checker.IPFullLength(uint16(hdrLen+len(data))), - checker.IPv4Options(ipv4Options), + checker.IPv4Options(expectOptions), checker.IPPayload(data), ) }, @@ -1284,7 +1296,7 @@ func TestWriteHeaderIncludedPacket(t *testing.T) { nicAddr: localIPv4Addr, remoteAddr: remoteIPv4Addr, pktGen: func(t *testing.T, src tcpip.Address) buffer.VectorisedView { - ip := header.IPv4(make([]byte, header.IPv4MinimumSize+ipv4Options.SizeWithPadding())) + ip := header.IPv4(make([]byte, header.IPv4MinimumSize+ipv4Options.Length())) ip.Encode(&header.IPv4Fields{ Protocol: transportProto, TTL: ipv4.DefaultTTL, @@ -1303,7 +1315,7 @@ func TestWriteHeaderIncludedPacket(t *testing.T) { netHdr := pkt.NetworkHeader() - hdrLen := header.IPv4MinimumSize + len(ipv4Options) + hdrLen := int(header.IPv4MinimumSize + ipv4Options.Length()) if len(netHdr.View()) != hdrLen { t.Errorf("got len(netHdr.View()) = %d, want = %d", len(netHdr.View()), hdrLen) } @@ -1313,7 +1325,7 @@ func TestWriteHeaderIncludedPacket(t *testing.T) { checker.DstAddr(remoteIPv4Addr), checker.IPv4HeaderLength(hdrLen), checker.IPFullLength(uint16(hdrLen+len(data))), - checker.IPv4Options(ipv4Options), + checker.IPv4Options(expectOptions), checker.IPPayload(data), ) }, diff --git a/pkg/tcpip/network/ipv4/igmp.go b/pkg/tcpip/network/ipv4/igmp.go index 18ccd28c3..0134fadc0 100644 --- a/pkg/tcpip/network/ipv4/igmp.go +++ b/pkg/tcpip/network/ipv4/igmp.go @@ -250,10 +250,10 @@ func (igmp *igmpState) writePacket(destAddress tcpip.Address, groupAddress tcpip Protocol: header.IGMPProtocolNumber, TTL: header.IGMPTTL, TOS: stack.DefaultTOS, + }, header.IPv4OptionsSerializer{ + &header.IPv4SerializableRouterAlertOption{}, }) - // TODO(b/162198658): set the ROUTER_ALERT option when sending Host - // Membership Reports. sent := igmp.ep.protocol.stack.Stats().IGMP.PacketsSent if err := igmp.ep.nic.WritePacketToRemote(header.EthernetAddressFromMulticastIPv4Address(destAddress), nil /* gso */, ProtocolNumber, pkt); err != nil { sent.Dropped.Increment() diff --git a/pkg/tcpip/network/ipv4/igmp_test.go b/pkg/tcpip/network/ipv4/igmp_test.go index d83b6c4a4..5e139377b 100644 --- a/pkg/tcpip/network/ipv4/igmp_test.go +++ b/pkg/tcpip/network/ipv4/igmp_test.go @@ -42,6 +42,9 @@ func validateIgmpPacket(t *testing.T, p channel.PacketInfo, remoteAddress tcpip. payload := header.IPv4(stack.PayloadSince(p.Pkt.NetworkHeader())) checker.IPv4(t, payload, checker.DstAddr(remoteAddress), + // TTL for an IGMP message must be 1 as per RFC 2236 section 2. + checker.TTL(1), + checker.IPv4RouterAlert(), checker.IGMP( checker.IGMPType(igmpType), checker.IGMPMaxRespTime(header.DecisecondToDuration(maxRespTime)), diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go index 354ac1e1d..4b34d0bfb 100644 --- a/pkg/tcpip/network/ipv4/ipv4.go +++ b/pkg/tcpip/network/ipv4/ipv4.go @@ -215,21 +215,18 @@ func (e *endpoint) NetworkProtocolNumber() tcpip.NetworkProtocolNumber { return e.protocol.Number() } -func (e *endpoint) addIPHeader(srcAddr, dstAddr tcpip.Address, pkt *stack.PacketBuffer, params stack.NetworkHeaderParams) { +func (e *endpoint) addIPHeader(srcAddr, dstAddr tcpip.Address, pkt *stack.PacketBuffer, params stack.NetworkHeaderParams, options header.IPv4OptionsSerializer) { hdrLen := header.IPv4MinimumSize - var opts header.IPv4Options - if params.Options != nil { - var ok bool - if opts, ok = params.Options.(header.IPv4Options); !ok { - panic(fmt.Sprintf("want IPv4Options, got %T", params.Options)) - } - hdrLen += opts.SizeWithPadding() - if hdrLen > header.IPv4MaximumHeaderSize { - // Since we have no way to report an error we must either panic or create - // a packet which is different to what was requested. Choose panic as this - // would be a programming error that should be caught in testing. - panic(fmt.Sprintf("IPv4 Options %d bytes, Max %d", params.Options.SizeWithPadding(), header.IPv4MaximumOptionsSize)) - } + var optLen int + if options != nil { + optLen = int(options.Length()) + } + hdrLen += optLen + if hdrLen > header.IPv4MaximumHeaderSize { + // Since we have no way to report an error we must either panic or create + // a packet which is different to what was requested. Choose panic as this + // would be a programming error that should be caught in testing. + panic(fmt.Sprintf("IPv4 Options %d bytes, Max %d", optLen, header.IPv4MaximumOptionsSize)) } ip := header.IPv4(pkt.NetworkHeader().Push(hdrLen)) length := uint16(pkt.Size()) @@ -245,7 +242,7 @@ func (e *endpoint) addIPHeader(srcAddr, dstAddr tcpip.Address, pkt *stack.Packet Protocol: uint8(params.Protocol), SrcAddr: srcAddr, DstAddr: dstAddr, - Options: opts, + Options: options, }) ip.SetChecksum(^ip.CalculateChecksum()) pkt.NetworkProtocolNumber = ProtocolNumber @@ -276,7 +273,7 @@ func (e *endpoint) handleFragments(r *stack.Route, gso *stack.GSO, networkMTU ui // WritePacket writes a packet to the given destination address and protocol. func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt *stack.PacketBuffer) *tcpip.Error { - e.addIPHeader(r.LocalAddress, r.RemoteAddress, pkt, params) + e.addIPHeader(r.LocalAddress, r.RemoteAddress, pkt, params, nil /* options */) // iptables filtering. All packets that reach here are locally // generated. @@ -364,7 +361,7 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.Packe } for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() { - e.addIPHeader(r.LocalAddress, r.RemoteAddress, pkt, params) + e.addIPHeader(r.LocalAddress, r.RemoteAddress, pkt, params, nil /* options */) networkMTU, err := calculateNetworkMTU(e.nic.MTU(), uint32(pkt.NetworkHeader().View().Size())) if err != nil { r.Stats().IP.OutgoingPacketErrors.IncrementBy(uint64(pkts.Len())) diff --git a/pkg/tcpip/network/ipv4/ipv4_test.go b/pkg/tcpip/network/ipv4/ipv4_test.go index 2d633ca23..9e2d2cfd6 100644 --- a/pkg/tcpip/network/ipv4/ipv4_test.go +++ b/pkg/tcpip/network/ipv4/ipv4_test.go @@ -103,105 +103,6 @@ func TestExcludeBroadcast(t *testing.T) { }) } -// TestIPv4Encode checks that ipv4.Encode correctly fills out the requested -// fields when options are supplied. -func TestIPv4EncodeOptions(t *testing.T) { - tests := []struct { - name string - options header.IPv4Options - encodedOptions header.IPv4Options // reply should look like this - wantIHL int - }{ - { - name: "valid no options", - wantIHL: header.IPv4MinimumSize, - }, - { - name: "one byte options", - options: header.IPv4Options{1}, - encodedOptions: header.IPv4Options{1, 0, 0, 0}, - wantIHL: header.IPv4MinimumSize + 4, - }, - { - name: "two byte options", - options: header.IPv4Options{1, 1}, - encodedOptions: header.IPv4Options{1, 1, 0, 0}, - wantIHL: header.IPv4MinimumSize + 4, - }, - { - name: "three byte options", - options: header.IPv4Options{1, 1, 1}, - encodedOptions: header.IPv4Options{1, 1, 1, 0}, - wantIHL: header.IPv4MinimumSize + 4, - }, - { - name: "four byte options", - options: header.IPv4Options{1, 1, 1, 1}, - encodedOptions: header.IPv4Options{1, 1, 1, 1}, - wantIHL: header.IPv4MinimumSize + 4, - }, - { - name: "five byte options", - options: header.IPv4Options{1, 1, 1, 1, 1}, - encodedOptions: header.IPv4Options{1, 1, 1, 1, 1, 0, 0, 0}, - wantIHL: header.IPv4MinimumSize + 8, - }, - { - name: "thirty nine byte options", - options: header.IPv4Options{ - 1, 2, 3, 4, 5, 6, 7, 8, - 9, 10, 11, 12, 13, 14, 15, 16, - 17, 18, 19, 20, 21, 22, 23, 24, - 25, 26, 27, 28, 29, 30, 31, 32, - 33, 34, 35, 36, 37, 38, 39, - }, - encodedOptions: header.IPv4Options{ - 1, 2, 3, 4, 5, 6, 7, 8, - 9, 10, 11, 12, 13, 14, 15, 16, - 17, 18, 19, 20, 21, 22, 23, 24, - 25, 26, 27, 28, 29, 30, 31, 32, - 33, 34, 35, 36, 37, 38, 39, 0, - }, - wantIHL: header.IPv4MinimumSize + 40, - }, - } - for _, test := range tests { - t.Run(test.name, func(t *testing.T) { - paddedOptionLength := test.options.SizeWithPadding() - ipHeaderLength := header.IPv4MinimumSize + paddedOptionLength - if ipHeaderLength > header.IPv4MaximumHeaderSize { - t.Fatalf("IP header length too large: got = %d, want <= %d ", ipHeaderLength, header.IPv4MaximumHeaderSize) - } - totalLen := uint16(ipHeaderLength) - hdr := buffer.NewPrependable(int(totalLen)) - ip := header.IPv4(hdr.Prepend(ipHeaderLength)) - // To check the padding works, poison the last byte of the options space. - if paddedOptionLength != len(test.options) { - ip.SetHeaderLength(uint8(ipHeaderLength)) - ip.Options()[paddedOptionLength-1] = 0xff - ip.SetHeaderLength(0) - } - ip.Encode(&header.IPv4Fields{ - Options: test.options, - }) - options := ip.Options() - wantOptions := test.encodedOptions - if got, want := int(ip.HeaderLength()), test.wantIHL; got != want { - t.Errorf("got IHL of %d, want %d", got, want) - } - - // cmp.Diff does not consider nil slices equal to empty slices, but we do. - if len(wantOptions) == 0 && len(options) == 0 { - return - } - - if diff := cmp.Diff(wantOptions, options); diff != "" { - t.Errorf("options mismatch (-want +got):\n%s", diff) - } - }) - } -} - func TestForwarding(t *testing.T) { const ( nicID1 = 1 @@ -452,14 +353,6 @@ func TestIPv4Sanity(t *testing.T) { options: header.IPv4Options{1, 1, 0, 0}, replyOptions: header.IPv4Options{1, 1, 0, 0}, }, - { - name: "Check option padding", - maxTotalLength: ipv4.MaxTotalSize, - transportProtocol: uint8(header.ICMPv4ProtocolNumber), - TTL: ttl, - options: header.IPv4Options{1, 1, 1}, - replyOptions: header.IPv4Options{1, 1, 1, 0}, - }, { name: "bad header length", headerLength: header.IPv4MinimumSize - 1, @@ -583,7 +476,7 @@ func TestIPv4Sanity(t *testing.T) { 68, 7, 5, 0, // ^ ^ Linux points here which is wrong. // | Not a multiple of 4 - 1, 2, 3, + 1, 2, 3, 0, }, shouldFail: true, expectErrorICMP: true, @@ -967,8 +860,10 @@ func TestIPv4Sanity(t *testing.T) { }, }) - paddedOptionLength := test.options.SizeWithPadding() - ipHeaderLength := header.IPv4MinimumSize + paddedOptionLength + if len(test.options)%4 != 0 { + t.Fatalf("options must be aligned to 32 bits, invalid test options: %x (len=%d)", test.options, len(test.options)) + } + ipHeaderLength := header.IPv4MinimumSize + len(test.options) if ipHeaderLength > header.IPv4MaximumHeaderSize { t.Fatalf("IP header length too large: got = %d, want <= %d ", ipHeaderLength, header.IPv4MaximumHeaderSize) } @@ -987,11 +882,6 @@ func TestIPv4Sanity(t *testing.T) { if test.maxTotalLength < totalLen { totalLen = test.maxTotalLength } - // To check the padding works, poison the options space. - if paddedOptionLength != len(test.options) { - ip.SetHeaderLength(uint8(ipHeaderLength)) - ip.Options()[paddedOptionLength-1] = 0x01 - } ip.Encode(&header.IPv4Fields{ TotalLength: totalLen, @@ -999,10 +889,19 @@ func TestIPv4Sanity(t *testing.T) { TTL: test.TTL, SrcAddr: remoteIPv4Addr, DstAddr: ipv4Addr.Address, - Options: test.options, }) if test.headerLength != 0 { ip.SetHeaderLength(test.headerLength) + } else { + // Set the calculated header length, since we may manually add options. + ip.SetHeaderLength(uint8(ipHeaderLength)) + } + if len(test.options) != 0 { + // Copy options manually. We do not use Encode for options so we can + // verify malformed options with handcrafted payloads. + if want, got := copy(ip.Options(), test.options), len(test.options); want != got { + t.Fatalf("got copy(ip.Options(), test.options) = %d, want = %d", got, want) + } } ip.SetChecksum(0) ipHeaderChecksum := ip.CalculateChecksum() @@ -1107,7 +1006,7 @@ func TestIPv4Sanity(t *testing.T) { } // If the IP options change size then the packet will change size, so // some IP header fields will need to be adjusted for the checks. - sizeChange := len(test.replyOptions) - paddedOptionLength + sizeChange := len(test.replyOptions) - len(test.options) checker.IPv4(t, replyIPHeader, checker.IPv4HeaderLength(ipHeaderLength+sizeChange), diff --git a/pkg/tcpip/network/multicast_group_test.go b/pkg/tcpip/network/multicast_group_test.go index 5276f1b44..95fb67986 100644 --- a/pkg/tcpip/network/multicast_group_test.go +++ b/pkg/tcpip/network/multicast_group_test.go @@ -90,6 +90,7 @@ func validateIGMPPacket(t *testing.T, p channel.PacketInfo, remoteAddress tcpip. checker.DstAddr(remoteAddress), // TTL for an IGMP message must be 1 as per RFC 2236 section 2. checker.TTL(1), + checker.IPv4RouterAlert(), checker.IGMP( checker.IGMPType(header.IGMPType(igmpType)), checker.IGMPMaxRespTime(header.DecisecondToDuration(maxRespTime)), diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go index 236e4e4c7..b334e27c4 100644 --- a/pkg/tcpip/stack/registration.go +++ b/pkg/tcpip/stack/registration.go @@ -259,15 +259,6 @@ const ( PacketLoop ) -// NetOptions is an interface that allows us to pass network protocol specific -// options through the Stack layer code. -type NetOptions interface { - // SizeWithPadding returns the amount of memory that must be allocated to - // hold the options given that the value must be rounded up to the next - // multiple of 4 bytes. - SizeWithPadding() int -} - // NetworkHeaderParams are the header parameters given as input by the // transport endpoint to the network. type NetworkHeaderParams struct { @@ -279,10 +270,6 @@ type NetworkHeaderParams struct { // TOS refers to TypeOfService or TrafficClass field of the IP-header. TOS uint8 - - // Options is a set of options to add to a network header (or nil). - // It will be protocol specific opaque information from higher layers. - Options NetOptions } // GroupAddressableEndpoint is an endpoint that supports group addressing. diff --git a/test/packetimpact/testbench/layers.go b/test/packetimpact/testbench/layers.go index 9df072cfd..dcff4ab36 100644 --- a/test/packetimpact/testbench/layers.go +++ b/test/packetimpact/testbench/layers.go @@ -298,14 +298,12 @@ func (l *IPv4) ToBytes() ([]byte, error) { // An IPv4 header is variable length depending on the size of the Options. hdrLen := header.IPv4MinimumSize if l.Options != nil { - hdrLen += l.Options.SizeWithPadding() + if len(*l.Options)%4 != 0 { + return nil, fmt.Errorf("invalid header options '%x (len=%d)'; must be 32 bit aligned", *l.Options, len(*l.Options)) + } + hdrLen += len(*l.Options) if hdrLen > header.IPv4MaximumHeaderSize { - // While ToBytes can be called on packets that were received as well - // as packets locally generated, it is physically impossible for a - // received packet to overflow this value so any such failure must - // be the result of a local programming error and not remotely - // triggered. A panic is therefore appropriate. - panic(fmt.Sprintf("IPv4 Options %d bytes, Max %d", len(*l.Options), header.IPv4MaximumOptionsSize)) + return nil, fmt.Errorf("IPv4 Options %d bytes, Max %d", len(*l.Options), header.IPv4MaximumOptionsSize) } } b := make([]byte, hdrLen) @@ -323,10 +321,6 @@ func (l *IPv4) ToBytes() ([]byte, error) { DstAddr: tcpip.Address(""), Options: nil, } - // Leave an empty options slice as nil. - if hdrLen > header.IPv4MinimumSize { - fields.Options = *l.Options - } if l.TOS != nil { fields.TOS = *l.TOS } @@ -373,18 +367,31 @@ func (l *IPv4) ToBytes() ([]byte, error) { if l.DstAddr != nil { fields.DstAddr = *l.DstAddr } - if l.Checksum != nil { - fields.Checksum = *l.Checksum - } + h.Encode(fields) - if l.Checksum == nil { - h.SetChecksum(^h.CalculateChecksum()) + + // Put raw option bytes from test definition in header. Options as raw bytes + // allows us to serialize malformed options, which is not possible with + // the provided serialization functions. + if l.Options != nil { + h.SetHeaderLength(h.HeaderLength() + uint8(len(*l.Options))) + if got, want := copy(h.Options(), *l.Options), len(*l.Options); got != want { + return nil, fmt.Errorf("failed to copy option bytes into header, got %d want %d", got, want) + } } + // Encode cannot set this incorrectly so we need to overwrite what it wrote // in order to test handling of a bad IHL value. if l.IHL != nil { h.SetHeaderLength(*l.IHL) } + + if l.Checksum == nil { + h.SetChecksum(^h.CalculateChecksum()) + } else { + h.SetChecksum(*l.Checksum) + } + return h, nil } -- cgit v1.2.3