diff options
Diffstat (limited to 'pkg/tcpip/header')
| -rw-r--r-- | pkg/tcpip/header/BUILD | 3 | ||||
| -rw-r--r-- | pkg/tcpip/header/ipv6_extension_headers.go | 344 | ||||
| -rw-r--r-- | pkg/tcpip/header/ipv6_extension_headers_test.go | 515 |
3 files changed, 862 insertions, 0 deletions
diff --git a/pkg/tcpip/header/BUILD b/pkg/tcpip/header/BUILD index 9da0d71f8..7094f3f0b 100644 --- a/pkg/tcpip/header/BUILD +++ b/pkg/tcpip/header/BUILD @@ -14,6 +14,7 @@ go_library( "interfaces.go", "ipv4.go", "ipv6.go", + "ipv6_extension_headers.go", "ipv6_fragment.go", "ndp_neighbor_advert.go", "ndp_neighbor_solicit.go", @@ -55,11 +56,13 @@ go_test( size = "small", srcs = [ "eth_test.go", + "ipv6_extension_headers_test.go", "ndp_test.go", ], library = ":header", deps = [ "//pkg/tcpip", + "//pkg/tcpip/buffer", "@com_github_google_go-cmp//cmp:go_default_library", ], ) diff --git a/pkg/tcpip/header/ipv6_extension_headers.go b/pkg/tcpip/header/ipv6_extension_headers.go new file mode 100644 index 000000000..b8866d4d2 --- /dev/null +++ b/pkg/tcpip/header/ipv6_extension_headers.go @@ -0,0 +1,344 @@ +// 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 + +import ( + "bufio" + "encoding/binary" + "fmt" + "io" + + "gvisor.dev/gvisor/pkg/tcpip/buffer" +) + +// IPv6ExtensionHeaderIdentifier is an IPv6 extension header identifier. +type IPv6ExtensionHeaderIdentifier uint8 + +const ( + // IPv6RoutingExtHdrIdentifier is the header identifier of a Routing extension + // header, as per RFC 8200 section 4.4. + IPv6RoutingExtHdrIdentifier IPv6ExtensionHeaderIdentifier = 43 + + // IPv6FragmentExtHdrIdentifier is the header identifier of a Fragment + // extension header, as per RFC 8200 section 4.5. + IPv6FragmentExtHdrIdentifier IPv6ExtensionHeaderIdentifier = 44 + + // IPv6NoNextHeaderIdentifier is the header identifier used to signify the end + // of an IPv6 payload, as per RFC 8200 section 4.7. + IPv6NoNextHeaderIdentifier IPv6ExtensionHeaderIdentifier = 59 +) + +const ( + // ipv6RoutingExtHdrSegmentsLeftIdx is the index to the Segments Left field + // within an IPv6RoutingExtHdr. + ipv6RoutingExtHdrSegmentsLeftIdx = 1 + + // ipv6FragmentExtHdrFragmentOffsetOffset is the offset to the start of the + // Fragment Offset field within an IPv6FragmentExtHdr. + ipv6FragmentExtHdrFragmentOffsetOffset = 0 + + // ipv6FragmentExtHdrFragmentOffsetShift is the least significant bits to + // discard from the Fragment Offset. + ipv6FragmentExtHdrFragmentOffsetShift = 3 + + // ipv6FragmentExtHdrFlagsIdx is the index to the flags field within an + // IPv6FragmentExtHdr. + ipv6FragmentExtHdrFlagsIdx = 1 + + // ipv6FragmentExtHdrMFlagMask is the mask of the More (M) flag within the + // flags field of an IPv6FragmentExtHdr. + ipv6FragmentExtHdrMFlagMask = 1 + + // ipv6FragmentExtHdrIdentificationOffset is the offset to the Identification + // field within an IPv6FragmentExtHdr. + ipv6FragmentExtHdrIdentificationOffset = 2 + + // ipv6ExtHdrLenBytesPerUnit is the unit size of an extension header's length + // field. That is, given a Length field of 2, the extension header expects + // 16 bytes following the first 8 bytes (see ipv6ExtHdrLenBytesExcluded for + // details about the first 8 bytes' exclusion from the Length field). + ipv6ExtHdrLenBytesPerUnit = 8 + + // ipv6ExtHdrLenBytesExcluded is the number of bytes excluded from an + // extension header's Length field following the Length field. + // + // The Length field excludes the first 8 bytes, but the Next Header and Length + // field take up the first 2 of the 8 bytes so we expect (at minimum) 6 bytes + // after the Length field. + // + // This ensures that every extension header is at least 8 bytes. + ipv6ExtHdrLenBytesExcluded = 6 + + // IPv6FragmentExtHdrFragmentOffsetBytesPerUnit is the unit size of a Fragment + // extension header's Fragment Offset field. That is, given a Fragment Offset + // of 2, the extension header is indiciating that the fragment's payload + // starts at the 16th byte in the reassembled packet. + IPv6FragmentExtHdrFragmentOffsetBytesPerUnit = 8 +) + +// IPv6PayloadHeader is implemented by the various headers that can be found +// in an IPv6 payload. +// +// These headers include IPv6 extension headers or upper layer data. +type IPv6PayloadHeader interface { + isIPv6PayloadHeader() +} + +// IPv6RawPayloadHeader the remainder of an IPv6 payload after an iterator +// encounters a Next Header field it does not recognize as an IPv6 extension +// header. +type IPv6RawPayloadHeader struct { + Identifier IPv6ExtensionHeaderIdentifier + Buf buffer.VectorisedView +} + +// isIPv6PayloadHeader implements IPv6PayloadHeader.isIPv6PayloadHeader. +func (IPv6RawPayloadHeader) isIPv6PayloadHeader() {} + +// IPv6RoutingExtHdr is a buffer holding the Routing extension header specific +// data as outlined in RFC 8200 section 4.4. +type IPv6RoutingExtHdr []byte + +// isIPv6PayloadHeader implements IPv6PayloadHeader.isIPv6PayloadHeader. +func (IPv6RoutingExtHdr) isIPv6PayloadHeader() {} + +// SegmentsLeft returns the Segments Left field. +func (b IPv6RoutingExtHdr) SegmentsLeft() uint8 { + return b[ipv6RoutingExtHdrSegmentsLeftIdx] +} + +// IPv6FragmentExtHdr is a buffer holding the Fragment extension header specific +// data as outlined in RFC 8200 section 4.5. +// +// Note, the buffer does not include the Next Header and Reserved fields. +type IPv6FragmentExtHdr [6]byte + +// isIPv6PayloadHeader implements IPv6PayloadHeader.isIPv6PayloadHeader. +func (IPv6FragmentExtHdr) isIPv6PayloadHeader() {} + +// FragmentOffset returns the Fragment Offset field. +// +// This value indicates where the buffer following the Fragment extension header +// starts in the target (reassembled) packet. +func (b IPv6FragmentExtHdr) FragmentOffset() uint16 { + return binary.BigEndian.Uint16(b[ipv6FragmentExtHdrFragmentOffsetOffset:]) >> ipv6FragmentExtHdrFragmentOffsetShift +} + +// More returns the More (M) flag. +// +// This indicates whether any fragments are expected to succeed b. +func (b IPv6FragmentExtHdr) More() bool { + return b[ipv6FragmentExtHdrFlagsIdx]&ipv6FragmentExtHdrMFlagMask != 0 +} + +// ID returns the Identification field. +// +// This value is used to uniquely identify the packet, between a +// souce and destination. +func (b IPv6FragmentExtHdr) ID() uint32 { + return binary.BigEndian.Uint32(b[ipv6FragmentExtHdrIdentificationOffset:]) +} + +// IPv6PayloadIterator is an iterator over the contents of an IPv6 payload. +// +// The IPv6 payload may contain IPv6 extension headers before any upper layer +// data. +// +// Note, between when an IPv6PayloadIterator is obtained and last used, no +// changes to the payload may happen. Doing so may cause undefined and +// unexpected behaviour. It is fine to obtain an IPv6PayloadIterator, iterate +// over the first few headers then modify the backing payload so long as the +// IPv6PayloadIterator obtained before modification is no longer used. +type IPv6PayloadIterator struct { + // The identifier of the next header to parse. + nextHdrIdentifier IPv6ExtensionHeaderIdentifier + + // reader is an io.Reader over payload. + reader bufio.Reader + payload buffer.VectorisedView + + // Indicates to the iterator that it should return the remaining payload as a + // raw payload on the next call to Next. + forceRaw bool +} + +// MakeIPv6PayloadIterator returns an iterator over the IPv6 payload containing +// extension headers, or a raw payload if the payload cannot be parsed. +func MakeIPv6PayloadIterator(nextHdrIdentifier IPv6ExtensionHeaderIdentifier, payload buffer.VectorisedView, check bool) (IPv6PayloadIterator, error) { + readers := payload.Readers() + readerPs := make([]io.Reader, 0, len(readers)) + for i := range readers { + readerPs = append(readerPs, &readers[i]) + } + + // We need a buffer of size 1 for calls to bufio.Reader.ReadByte. + reader := *bufio.NewReaderSize(io.MultiReader(readerPs...), 1) + + it := IPv6PayloadIterator{ + nextHdrIdentifier: nextHdrIdentifier, + payload: payload.Clone(nil), + reader: reader, + } + + var err error + + if check { + for { + var done bool + if _, done, err = it.Next(); err != nil || done { + break + } + } + + // Reset it (and its underlying readers) before returning it. + for i := range readers { + readers[i].Seek(0, io.SeekStart) + } + reader.Reset(io.MultiReader(readerPs...)) + it = IPv6PayloadIterator{ + nextHdrIdentifier: nextHdrIdentifier, + payload: payload.Clone(nil), + reader: reader, + } + } + + return it, err +} + +// AsRawHeader returns the remaining payload of i as a raw header and +// completes the iterator. +// +// Calls to Next after calling AsRawHeader on i will indicate that the +// iterator is done. +func (i *IPv6PayloadIterator) AsRawHeader() IPv6RawPayloadHeader { + buf := i.payload + identifier := i.nextHdrIdentifier + + // Mark i as done. + *i = IPv6PayloadIterator{ + nextHdrIdentifier: IPv6NoNextHeaderIdentifier, + } + + return IPv6RawPayloadHeader{Identifier: identifier, Buf: buf} +} + +// Next returns the next item in the payload. +// +// If the next item is not a known IPv6 extension header, IPv6RawPayloadHeader +// will be returned with the remaining bytes and next header identifier. +// +// The return is of the format (header, done, error). done will be true when +// Next is unable to return anything because the iterator has reached the end of +// the payload, or an error occured. +func (i *IPv6PayloadIterator) Next() (IPv6PayloadHeader, bool, error) { + // We could be forced to return i as a raw header when the previous header was + // a fragment extension header as the data following the fragment extension + // header may not be complete. + if i.forceRaw { + return i.AsRawHeader(), false, nil + } + + // Is the header we are parsing a known extension header? + switch i.nextHdrIdentifier { + case IPv6RoutingExtHdrIdentifier: + nextHdrIdentifier, bytes, err := i.nextHeaderData(false /* fragmentHdr */, nil) + if err != nil { + return nil, true, err + } + + i.nextHdrIdentifier = nextHdrIdentifier + return IPv6RoutingExtHdr(bytes), false, nil + case IPv6FragmentExtHdrIdentifier: + var data [6]byte + // We ignore the returned bytes becauase we know the fragment extension + // header specific data will fit in data. + nextHdrIdentifier, _, err := i.nextHeaderData(true /* fragmentHdr */, data[:]) + if err != nil { + return nil, true, err + } + + fragmentExtHdr := IPv6FragmentExtHdr(data) + + // If the packet is a fragmented packet, do not attempt to parse + // anything after the fragment extension header as the data following + // the extension header may not be complete. + if fragmentExtHdr.More() || fragmentExtHdr.FragmentOffset() != 0 { + i.forceRaw = true + } + + i.nextHdrIdentifier = nextHdrIdentifier + return fragmentExtHdr, false, nil + case IPv6NoNextHeaderIdentifier: + // This indicates the end of the IPv6 payload. + return nil, true, nil + + default: + // The header we are parsing is not a known extension header. Return the + // raw payload. + return i.AsRawHeader(), false, nil + } +} + +// nextHeaderData returns the extension header's Next Header field and raw data. +// +// fragmentHdr indicates that the extension header being parsed is the Fragment +// extension header so the Length field should be ignored as it is Reserved +// for the Fragment extension header. +// +// If bytes is not nil, extension header specific data will be read into bytes +// if it has enough capacity. If bytes is provided but does not have enough +// capacity for the data, nextHeaderData will panic. +func (i *IPv6PayloadIterator) nextHeaderData(fragmentHdr bool, bytes []byte) (IPv6ExtensionHeaderIdentifier, []byte, error) { + // We ignore the number of bytes read because we know we will only ever read + // at max 1 bytes since rune has a length of 1. If we read 0 bytes, the Read + // would return io.EOF to indicate that io.Reader has reached the end of the + // payload. + nextHdrIdentifier, err := i.reader.ReadByte() + i.payload.TrimFront(1) + if err != nil { + return 0, nil, fmt.Errorf("error when reading the Next Header field for extension header with id = %d: %w", i.nextHdrIdentifier, err) + } + + var length uint8 + length, err = i.reader.ReadByte() + i.payload.TrimFront(1) + if err != nil { + var ret error + if fragmentHdr { + ret = fmt.Errorf("error when reading the Length field for extension header with id = %d: %w", i.nextHdrIdentifier, err) + } else { + ret = fmt.Errorf("error when reading the Reserved field for extension header with id = %d: %w", i.nextHdrIdentifier, err) + } + return 0, nil, ret + } + if fragmentHdr { + length = 0 + } + + bytesLen := int(length)*ipv6ExtHdrLenBytesPerUnit + ipv6ExtHdrLenBytesExcluded + if bytes == nil { + bytes = make([]byte, bytesLen) + } else if n := len(bytes); n < bytesLen { + panic(fmt.Sprintf("bytes only has space for %d bytes but need space for %d bytes (length = %d) for extension header with id = %d", n, bytesLen, length, i.nextHdrIdentifier)) + } + + n, err := io.ReadFull(&i.reader, bytes) + i.payload.TrimFront(n) + if err != nil { + return 0, nil, fmt.Errorf("read %d out of %d extension header data bytes (length = %d) for header with id = %d: %w", n, bytesLen, length, i.nextHdrIdentifier, err) + } + + return IPv6ExtensionHeaderIdentifier(nextHdrIdentifier), bytes, nil +} diff --git a/pkg/tcpip/header/ipv6_extension_headers_test.go b/pkg/tcpip/header/ipv6_extension_headers_test.go new file mode 100644 index 000000000..4bfdc77c4 --- /dev/null +++ b/pkg/tcpip/header/ipv6_extension_headers_test.go @@ -0,0 +1,515 @@ +// 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 + +import ( + "bytes" + "errors" + "io" + "testing" + + "github.com/google/go-cmp/cmp" + "gvisor.dev/gvisor/pkg/tcpip/buffer" +) + +// Equal returns true of a and b are equivalent. +// +// Note, Equal will return true if a and b hold the same Identifier value and +// contain the same bytes in Buf, even if the bytes are split across views +// differently. +// +// Needed to use cmp.Equal on IPv6RawPayloadHeader as it contains unexported +// fields. +func (a IPv6RawPayloadHeader) Equal(b IPv6RawPayloadHeader) bool { + return a.Identifier == b.Identifier && bytes.Equal(a.Buf.ToView(), b.Buf.ToView()) +} + +func TestIPv6RoutingExtHdr(t *testing.T) { + tests := []struct { + name string + bytes []byte + segmentsLeft uint8 + }{ + { + name: "Zeroes", + bytes: []byte{0, 0, 0, 0, 0, 0}, + segmentsLeft: 0, + }, + { + name: "Ones", + bytes: []byte{1, 1, 1, 1, 1, 1}, + segmentsLeft: 1, + }, + { + name: "Mixed", + bytes: []byte{1, 2, 3, 4, 5, 6}, + segmentsLeft: 2, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + extHdr := IPv6RoutingExtHdr(test.bytes) + if got := extHdr.SegmentsLeft(); got != test.segmentsLeft { + t.Errorf("got SegmentsLeft() = %d, want = %d", got, test.segmentsLeft) + } + }) + } +} + +func TestIPv6FragmentExtHdr(t *testing.T) { + tests := []struct { + name string + bytes [6]byte + fragmentOffset uint16 + more bool + id uint32 + }{ + { + name: "Zeroes", + bytes: [6]byte{0, 0, 0, 0, 0, 0}, + fragmentOffset: 0, + more: false, + id: 0, + }, + { + name: "Ones", + bytes: [6]byte{0, 9, 0, 0, 0, 1}, + fragmentOffset: 1, + more: true, + id: 1, + }, + { + name: "Mixed", + bytes: [6]byte{68, 9, 128, 4, 2, 1}, + fragmentOffset: 2177, + more: true, + id: 2147746305, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + extHdr := IPv6FragmentExtHdr(test.bytes) + if got := extHdr.FragmentOffset(); got != test.fragmentOffset { + t.Errorf("got FragmentOffset() = %d, want = %d", got, test.fragmentOffset) + } + if got := extHdr.More(); got != test.more { + t.Errorf("got More() = %t, want = %t", got, test.more) + } + if got := extHdr.ID(); got != test.id { + t.Errorf("got ID() = %d, want = %d", got, test.id) + } + }) + } +} + +func makeVectorisedViewFromByteBuffers(bs ...[]byte) buffer.VectorisedView { + size := 0 + var vs []buffer.View + + for _, b := range bs { + vs = append(vs, buffer.View(b)) + size += len(b) + } + + return buffer.NewVectorisedView(size, vs) +} + +func TestIPv6ExtHdrIterErr(t *testing.T) { + tests := []struct { + name string + firstNextHdr IPv6ExtensionHeaderIdentifier + payload buffer.VectorisedView + err error + }{ + { + name: "Upper layer only without data", + firstNextHdr: 255, + }, + { + name: "Upper layer only with data", + firstNextHdr: 255, + payload: makeVectorisedViewFromByteBuffers([]byte{1, 2, 3, 4}), + }, + + { + name: "No next header", + firstNextHdr: IPv6NoNextHeaderIdentifier, + }, + { + name: "No next header with data", + firstNextHdr: IPv6NoNextHeaderIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{1, 2, 3, 4}), + }, + + { + name: "Valid single fragment", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 0, 68, 9, 128, 4, 2, 1}), + }, + { + name: "Fragment too small", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 0, 68, 9, 128, 4, 2}), + err: io.ErrUnexpectedEOF, + }, + + { + name: "Valid single routing", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 0, 1, 2, 3, 4, 5, 6}), + }, + { + name: "Valid single routing across views", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 0, 1, 2}, []byte{3, 4, 5, 6}), + }, + { + name: "Routing too small with zero length field", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 0, 1, 2, 3, 4, 5}), + err: io.ErrUnexpectedEOF, + }, + { + name: "Valid routing with non-zero length field", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 1, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8}), + }, + { + name: "Valid routing with non-zero length field across views", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 1, 1, 2, 3, 4, 5, 6}, []byte{1, 2, 3, 4, 5, 6, 7, 8}), + }, + { + name: "Routing too small with non-zero length field", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 1, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7}), + err: io.ErrUnexpectedEOF, + }, + { + name: "Routing too small with non-zero length field across views", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{255, 1, 1, 2, 3, 4, 5, 6}, []byte{1, 2, 3, 4, 5, 6, 7}), + err: io.ErrUnexpectedEOF, + }, + + { + name: "Mixed", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Fragment extension header. + uint8(IPv6RoutingExtHdrIdentifier), 0, 68, 9, 128, 4, 2, 1, + + // Routing extension header. + 255, 0, 1, 2, 3, 4, 5, 6, + + // Upper layer data. + 1, 2, 3, 4, + }), + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + if _, err := MakeIPv6PayloadIterator(test.firstNextHdr, test.payload, false); err != nil { + t.Errorf("got MakeIPv6PayloadIterator(%d, _, false) = %s, want = nil", test.firstNextHdr, err) + } + + if _, err := MakeIPv6PayloadIterator(test.firstNextHdr, test.payload, true); !errors.Is(err, test.err) { + t.Errorf("got MakeIPv6PayloadIterator(%d, _, true) = %v, want = %v", test.firstNextHdr, err, test.err) + } + }) + } +} + +func TestIPv6ExtHdrIter(t *testing.T) { + routingExtHdrWithUpperLayerData := buffer.View([]byte{255, 0, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4}) + upperLayerData := buffer.View([]byte{1, 2, 3, 4}) + tests := []struct { + name string + firstNextHdr IPv6ExtensionHeaderIdentifier + payload buffer.VectorisedView + expected []IPv6PayloadHeader + }{ + // With a non-atomic fragment, the payload after the fragment will not be + // parsed because the payload may not be complete. + { + name: "fragment - routing - upper", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Fragment extension header. + uint8(IPv6RoutingExtHdrIdentifier), 0, 68, 9, 128, 4, 2, 1, + + // Routing extension header. + 255, 0, 1, 2, 3, 4, 5, 6, + + // Upper layer data. + 1, 2, 3, 4, + }), + expected: []IPv6PayloadHeader{ + IPv6FragmentExtHdr([6]byte{68, 9, 128, 4, 2, 1}), + IPv6RawPayloadHeader{ + Identifier: IPv6RoutingExtHdrIdentifier, + Buf: routingExtHdrWithUpperLayerData.ToVectorisedView(), + }, + }, + }, + { + name: "fragment - routing - upper (across views)", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Fragment extension header. + uint8(IPv6RoutingExtHdrIdentifier), 0, 68, 9, 128, 4, 2, 1, + + // Routing extension header. + 255, 0, 1, 2}, []byte{3, 4, 5, 6, + + // Upper layer data. + 1, 2, 3, 4, + }), + expected: []IPv6PayloadHeader{ + IPv6FragmentExtHdr([6]byte{68, 9, 128, 4, 2, 1}), + IPv6RawPayloadHeader{ + Identifier: IPv6RoutingExtHdrIdentifier, + Buf: routingExtHdrWithUpperLayerData.ToVectorisedView(), + }, + }, + }, + + // If we have an atomic fragment, the payload following the fragment + // extension header should be parsed normally. + { + name: "atomic fragment - routing - upper", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Fragment extension header. + // + // Reserved bits are 1 which should not affect anything. + uint8(IPv6RoutingExtHdrIdentifier), 255, 0, 6, 128, 4, 2, 1, + + // Routing extension header. + 255, 0, 1, 2, 3, 4, 5, 6, + + // Upper layer data. + 1, 2, 3, 4, + }), + expected: []IPv6PayloadHeader{ + IPv6FragmentExtHdr([6]byte{0, 6, 128, 4, 2, 1}), + IPv6RoutingExtHdr([]byte{1, 2, 3, 4, 5, 6}), + IPv6RawPayloadHeader{ + Identifier: 255, + Buf: upperLayerData.ToVectorisedView(), + }, + }, + }, + { + name: "atomic fragment - routing - upper (across views)", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Fragment extension header. + // + // Reserved bits are 1 which should not affect anything. + uint8(IPv6RoutingExtHdrIdentifier), 255, 0, 6}, []byte{128, 4, 2, 1, + + // Routing extension header. + 255, 0, 1, 2}, []byte{3, 4, 5, 6, + + // Upper layer data. + 1, 2}, []byte{3, 4}), + expected: []IPv6PayloadHeader{ + IPv6FragmentExtHdr([6]byte{0, 6, 128, 4, 2, 1}), + IPv6RoutingExtHdr([]byte{1, 2, 3, 4, 5, 6}), + IPv6RawPayloadHeader{ + Identifier: 255, + Buf: makeVectorisedViewFromByteBuffers(upperLayerData[:2], upperLayerData[2:]), + }, + }, + }, + { + name: "atomic fragment - no next header", + firstNextHdr: IPv6FragmentExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Fragment extension header. + // + // Res (Reserved) bits are 1 which should not affect anything. + uint8(IPv6NoNextHeaderIdentifier), 0, 0, 6, 128, 4, 2, 1, + + // Random data. + 1, 2, 3, 4, + }), + expected: []IPv6PayloadHeader{ + IPv6FragmentExtHdr([6]byte{0, 6, 128, 4, 2, 1}), + }, + }, + { + name: "routing - atomic fragment - no next header", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Routing extension header. + uint8(IPv6FragmentExtHdrIdentifier), 0, 1, 2, 3, 4, 5, 6, + + // Fragment extension header. + // + // Reserved bits are 1 which should not affect anything. + uint8(IPv6NoNextHeaderIdentifier), 0, 0, 6, 128, 4, 2, 1, + + // Random data. + 1, 2, 3, 4, + }), + expected: []IPv6PayloadHeader{ + IPv6RoutingExtHdr([]byte{1, 2, 3, 4, 5, 6}), + IPv6FragmentExtHdr([6]byte{0, 6, 128, 4, 2, 1}), + }, + }, + { + name: "routing - atomic fragment - no next header (across views)", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Routing extension header. + uint8(IPv6FragmentExtHdrIdentifier), 0, 1, 2, 3, 4, 5, 6, + + // Fragment extension header. + // + // Reserved bits are 1 which should not affect anything. + uint8(IPv6NoNextHeaderIdentifier), 255, 0, 6}, []byte{128, 4, 2, 1, + + // Random data. + 1, 2, 3, 4, + }), + expected: []IPv6PayloadHeader{ + IPv6RoutingExtHdr([]byte{1, 2, 3, 4, 5, 6}), + IPv6FragmentExtHdr([6]byte{0, 6, 128, 4, 2, 1}), + }, + }, + { + name: "routing - fragment - no next header", + firstNextHdr: IPv6RoutingExtHdrIdentifier, + payload: makeVectorisedViewFromByteBuffers([]byte{ + // Routing extension header. + uint8(IPv6FragmentExtHdrIdentifier), 0, 1, 2, 3, 4, 5, 6, + + // Fragment extension header. + // + // Fragment Offset = 32; Res = 6. + uint8(IPv6NoNextHeaderIdentifier), 0, 1, 6, 128, 4, 2, 1, + + // Random data. + 1, 2, 3, 4, + }), + expected: []IPv6PayloadHeader{ + IPv6RoutingExtHdr([]byte{1, 2, 3, 4, 5, 6}), + IPv6FragmentExtHdr([6]byte{1, 6, 128, 4, 2, 1}), + IPv6RawPayloadHeader{ + Identifier: IPv6NoNextHeaderIdentifier, + Buf: upperLayerData.ToVectorisedView(), + }, + }, + }, + + // Test the raw payload for common transport layer protocol numbers. + { + name: "TCP raw payload", + firstNextHdr: IPv6ExtensionHeaderIdentifier(TCPProtocolNumber), + payload: makeVectorisedViewFromByteBuffers(upperLayerData), + expected: []IPv6PayloadHeader{IPv6RawPayloadHeader{ + Identifier: IPv6ExtensionHeaderIdentifier(TCPProtocolNumber), + Buf: upperLayerData.ToVectorisedView(), + }}, + }, + { + name: "UDP raw payload", + firstNextHdr: IPv6ExtensionHeaderIdentifier(UDPProtocolNumber), + payload: makeVectorisedViewFromByteBuffers(upperLayerData), + expected: []IPv6PayloadHeader{IPv6RawPayloadHeader{ + Identifier: IPv6ExtensionHeaderIdentifier(UDPProtocolNumber), + Buf: upperLayerData.ToVectorisedView(), + }}, + }, + { + name: "ICMPv4 raw payload", + firstNextHdr: IPv6ExtensionHeaderIdentifier(ICMPv4ProtocolNumber), + payload: makeVectorisedViewFromByteBuffers(upperLayerData), + expected: []IPv6PayloadHeader{IPv6RawPayloadHeader{ + Identifier: IPv6ExtensionHeaderIdentifier(ICMPv4ProtocolNumber), + Buf: upperLayerData.ToVectorisedView(), + }}, + }, + { + name: "ICMPv6 raw payload", + firstNextHdr: IPv6ExtensionHeaderIdentifier(ICMPv6ProtocolNumber), + payload: makeVectorisedViewFromByteBuffers(upperLayerData), + expected: []IPv6PayloadHeader{IPv6RawPayloadHeader{ + Identifier: IPv6ExtensionHeaderIdentifier(ICMPv6ProtocolNumber), + Buf: upperLayerData.ToVectorisedView(), + }}, + }, + { + name: "Unknwon next header raw payload", + firstNextHdr: 255, + payload: makeVectorisedViewFromByteBuffers(upperLayerData), + expected: []IPv6PayloadHeader{IPv6RawPayloadHeader{ + Identifier: 255, + Buf: upperLayerData.ToVectorisedView(), + }}, + }, + { + name: "Unknwon next header raw payload (across views)", + firstNextHdr: 255, + payload: makeVectorisedViewFromByteBuffers(upperLayerData[:2], upperLayerData[2:]), + expected: []IPv6PayloadHeader{IPv6RawPayloadHeader{ + Identifier: 255, + Buf: makeVectorisedViewFromByteBuffers(upperLayerData[:2], upperLayerData[2:]), + }}, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + it, err := MakeIPv6PayloadIterator(test.firstNextHdr, test.payload, true) + if err != nil { + t.Fatalf("MakeIPv6PayloadIterator(%d, _ true): %s", test.firstNextHdr, err) + } + + for i, e := range test.expected { + extHdr, done, err := it.Next() + if err != nil { + t.Errorf("(i=%d) Next(): %s", i, err) + } + if done { + t.Errorf("(i=%d) unexpectedly done iterating", i) + } + if diff := cmp.Diff(e, extHdr); diff != "" { + t.Errorf("(i=%d) got ext hdr mismatch (-want +got):\n%s", i, diff) + } + + if t.Failed() { + t.FailNow() + } + } + + extHdr, done, err := it.Next() + if err != nil { + t.Errorf("(last) Next(): %s", err) + } + if !done { + t.Errorf("(last) iterator unexpectedly not done") + } + if extHdr != nil { + t.Errorf("(last) got Next() = %T, want = nil", extHdr) + } + }) + } +} |