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Diffstat (limited to 'test/packetimpact/testbench/layers.go')
-rw-r--r-- | test/packetimpact/testbench/layers.go | 1386 |
1 files changed, 0 insertions, 1386 deletions
diff --git a/test/packetimpact/testbench/layers.go b/test/packetimpact/testbench/layers.go deleted file mode 100644 index 95bafa876..000000000 --- a/test/packetimpact/testbench/layers.go +++ /dev/null @@ -1,1386 +0,0 @@ -// 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 testbench - -import ( - "encoding/hex" - "fmt" - "reflect" - "strings" - - "github.com/google/go-cmp/cmp" - "github.com/google/go-cmp/cmp/cmpopts" - "go.uber.org/multierr" - "gvisor.dev/gvisor/pkg/tcpip" - "gvisor.dev/gvisor/pkg/tcpip/buffer" - "gvisor.dev/gvisor/pkg/tcpip/header" -) - -// Layer is the interface that all encapsulations must implement. -// -// A Layer is an encapsulation in a packet, such as TCP, IPv4, IPv6, etc. A -// Layer contains all the fields of the encapsulation. Each field is a pointer -// and may be nil. -type Layer interface { - fmt.Stringer - - // ToBytes converts the Layer into bytes. In places where the Layer's field - // isn't nil, the value that is pointed to is used. When the field is nil, a - // reasonable default for the Layer is used. For example, "64" for IPv4 TTL - // and a calculated checksum for TCP or IP. Some layers require information - // from the previous or next layers in order to compute a default, such as - // TCP's checksum or Ethernet's type, so each Layer has a doubly-linked list - // to the layer's neighbors. - ToBytes() ([]byte, error) - - // match checks if the current Layer matches the provided Layer. If either - // Layer has a nil in a given field, that field is considered matching. - // Otherwise, the values pointed to by the fields must match. The LayerBase is - // ignored. - match(Layer) bool - - // length in bytes of the current encapsulation - length() int - - // next gets a pointer to the encapsulated Layer. - next() Layer - - // prev gets a pointer to the Layer encapsulating this one. - Prev() Layer - - // setNext sets the pointer to the encapsulated Layer. - setNext(Layer) - - // setPrev sets the pointer to the Layer encapsulating this one. - setPrev(Layer) - - // merge overrides the values in the interface with the provided values. - merge(Layer) error -} - -// LayerBase is the common elements of all layers. -type LayerBase struct { - nextLayer Layer - prevLayer Layer -} - -func (lb *LayerBase) next() Layer { - return lb.nextLayer -} - -// Prev returns the previous layer. -func (lb *LayerBase) Prev() Layer { - return lb.prevLayer -} - -func (lb *LayerBase) setNext(l Layer) { - lb.nextLayer = l -} - -func (lb *LayerBase) setPrev(l Layer) { - lb.prevLayer = l -} - -// equalLayer compares that two Layer structs match while ignoring field in -// which either input has a nil and also ignoring the LayerBase of the inputs. -func equalLayer(x, y Layer) bool { - if x == nil || y == nil { - return true - } - // opt ignores comparison pairs where either of the inputs is a nil. - opt := cmp.FilterValues(func(x, y interface{}) bool { - for _, l := range []interface{}{x, y} { - v := reflect.ValueOf(l) - if (v.Kind() == reflect.Ptr || v.Kind() == reflect.Slice) && v.IsNil() { - return true - } - } - return false - }, cmp.Ignore()) - return cmp.Equal(x, y, opt, cmpopts.IgnoreTypes(LayerBase{})) -} - -// mergeLayer merges y into x. Any fields for which y has a non-nil value, that -// value overwrite the corresponding fields in x. -func mergeLayer(x, y Layer) error { - if y == nil { - return nil - } - if reflect.TypeOf(x) != reflect.TypeOf(y) { - return fmt.Errorf("can't merge %T into %T", y, x) - } - vx := reflect.ValueOf(x).Elem() - vy := reflect.ValueOf(y).Elem() - t := vy.Type() - for i := 0; i < vy.NumField(); i++ { - t := t.Field(i) - if t.Anonymous { - // Ignore the LayerBase in the Layer struct. - continue - } - v := vy.Field(i) - if v.IsNil() { - continue - } - vx.Field(i).Set(v) - } - return nil -} - -func stringLayer(l Layer) string { - v := reflect.ValueOf(l).Elem() - t := v.Type() - var ret []string - for i := 0; i < v.NumField(); i++ { - t := t.Field(i) - if t.Anonymous { - // Ignore the LayerBase in the Layer struct. - continue - } - v := v.Field(i) - if v.IsNil() { - continue - } - v = reflect.Indirect(v) - if v.Kind() == reflect.Slice && v.Type().Elem().Kind() == reflect.Uint8 { - ret = append(ret, fmt.Sprintf("%s:\n%v", t.Name, hex.Dump(v.Bytes()))) - } else { - ret = append(ret, fmt.Sprintf("%s:%v", t.Name, v)) - } - } - return fmt.Sprintf("&%s{%s}", t, strings.Join(ret, " ")) -} - -// Ether can construct and match an ethernet encapsulation. -type Ether struct { - LayerBase - SrcAddr *tcpip.LinkAddress - DstAddr *tcpip.LinkAddress - Type *tcpip.NetworkProtocolNumber -} - -func (l *Ether) String() string { - return stringLayer(l) -} - -// ToBytes implements Layer.ToBytes. -func (l *Ether) ToBytes() ([]byte, error) { - b := make([]byte, header.EthernetMinimumSize) - h := header.Ethernet(b) - fields := &header.EthernetFields{} - if l.SrcAddr != nil { - fields.SrcAddr = *l.SrcAddr - } - if l.DstAddr != nil { - fields.DstAddr = *l.DstAddr - } - if l.Type != nil { - fields.Type = *l.Type - } else { - switch n := l.next().(type) { - case *IPv4: - fields.Type = header.IPv4ProtocolNumber - case *IPv6: - fields.Type = header.IPv6ProtocolNumber - default: - return nil, fmt.Errorf("ethernet header's next layer is unrecognized: %#v", n) - } - } - h.Encode(fields) - return h, nil -} - -// LinkAddress is a helper routine that allocates a new tcpip.LinkAddress value -// to store v and returns a pointer to it. -func LinkAddress(v tcpip.LinkAddress) *tcpip.LinkAddress { - return &v -} - -// NetworkProtocolNumber is a helper routine that allocates a new -// tcpip.NetworkProtocolNumber value to store v and returns a pointer to it. -func NetworkProtocolNumber(v tcpip.NetworkProtocolNumber) *tcpip.NetworkProtocolNumber { - return &v -} - -// layerParser parses the input bytes and returns a Layer along with the next -// layerParser to run. If there is no more parsing to do, the returned -// layerParser is nil. -type layerParser func([]byte) (Layer, layerParser) - -// parse parses bytes starting with the first layerParser and using successive -// layerParsers until all the bytes are parsed. -func parse(parser layerParser, b []byte) Layers { - var layers Layers - for { - var layer Layer - layer, parser = parser(b) - layers = append(layers, layer) - if parser == nil { - break - } - b = b[layer.length():] - } - layers.linkLayers() - return layers -} - -// parseEther parses the bytes assuming that they start with an ethernet header -// and continues parsing further encapsulations. -func parseEther(b []byte) (Layer, layerParser) { - h := header.Ethernet(b) - ether := Ether{ - SrcAddr: LinkAddress(h.SourceAddress()), - DstAddr: LinkAddress(h.DestinationAddress()), - Type: NetworkProtocolNumber(h.Type()), - } - var nextParser layerParser - switch h.Type() { - case header.IPv4ProtocolNumber: - nextParser = parseIPv4 - case header.IPv6ProtocolNumber: - nextParser = parseIPv6 - default: - // Assume that the rest is a payload. - nextParser = parsePayload - } - return ðer, nextParser -} - -func (l *Ether) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *Ether) length() int { - return header.EthernetMinimumSize -} - -// merge implements Layer.merge. -func (l *Ether) merge(other Layer) error { - return mergeLayer(l, other) -} - -// IPv4 can construct and match an IPv4 encapsulation. -type IPv4 struct { - LayerBase - IHL *uint8 - TOS *uint8 - TotalLength *uint16 - ID *uint16 - Flags *uint8 - FragmentOffset *uint16 - TTL *uint8 - Protocol *uint8 - Checksum *uint16 - SrcAddr *tcpip.Address - DstAddr *tcpip.Address -} - -func (l *IPv4) String() string { - return stringLayer(l) -} - -// ToBytes implements Layer.ToBytes. -func (l *IPv4) ToBytes() ([]byte, error) { - b := make([]byte, header.IPv4MinimumSize) - h := header.IPv4(b) - fields := &header.IPv4Fields{ - IHL: 20, - TOS: 0, - TotalLength: 0, - ID: 0, - Flags: 0, - FragmentOffset: 0, - TTL: 64, - Protocol: 0, - Checksum: 0, - SrcAddr: tcpip.Address(""), - DstAddr: tcpip.Address(""), - } - if l.TOS != nil { - fields.TOS = *l.TOS - } - if l.TotalLength != nil { - fields.TotalLength = *l.TotalLength - } else { - fields.TotalLength = uint16(l.length()) - current := l.next() - for current != nil { - fields.TotalLength += uint16(current.length()) - current = current.next() - } - } - if l.ID != nil { - fields.ID = *l.ID - } - if l.Flags != nil { - fields.Flags = *l.Flags - } - if l.FragmentOffset != nil { - fields.FragmentOffset = *l.FragmentOffset - } - if l.TTL != nil { - fields.TTL = *l.TTL - } - if l.Protocol != nil { - fields.Protocol = *l.Protocol - } else { - switch n := l.next().(type) { - case *TCP: - fields.Protocol = uint8(header.TCPProtocolNumber) - case *UDP: - fields.Protocol = uint8(header.UDPProtocolNumber) - case *ICMPv4: - fields.Protocol = uint8(header.ICMPv4ProtocolNumber) - default: - // TODO(b/150301488): Support more protocols as needed. - return nil, fmt.Errorf("ipv4 header's next layer is unrecognized: %#v", n) - } - } - if l.SrcAddr != nil { - fields.SrcAddr = *l.SrcAddr - } - 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()) - } - return h, nil -} - -// Uint16 is a helper routine that allocates a new -// uint16 value to store v and returns a pointer to it. -func Uint16(v uint16) *uint16 { - return &v -} - -// Uint8 is a helper routine that allocates a new -// uint8 value to store v and returns a pointer to it. -func Uint8(v uint8) *uint8 { - return &v -} - -// Address is a helper routine that allocates a new tcpip.Address value to store -// v and returns a pointer to it. -func Address(v tcpip.Address) *tcpip.Address { - return &v -} - -// parseIPv4 parses the bytes assuming that they start with an ipv4 header and -// continues parsing further encapsulations. -func parseIPv4(b []byte) (Layer, layerParser) { - h := header.IPv4(b) - tos, _ := h.TOS() - ipv4 := IPv4{ - IHL: Uint8(h.HeaderLength()), - TOS: &tos, - TotalLength: Uint16(h.TotalLength()), - ID: Uint16(h.ID()), - Flags: Uint8(h.Flags()), - FragmentOffset: Uint16(h.FragmentOffset()), - TTL: Uint8(h.TTL()), - Protocol: Uint8(h.Protocol()), - Checksum: Uint16(h.Checksum()), - SrcAddr: Address(h.SourceAddress()), - DstAddr: Address(h.DestinationAddress()), - } - var nextParser layerParser - switch h.TransportProtocol() { - case header.TCPProtocolNumber: - nextParser = parseTCP - case header.UDPProtocolNumber: - nextParser = parseUDP - case header.ICMPv4ProtocolNumber: - nextParser = parseICMPv4 - default: - // Assume that the rest is a payload. - nextParser = parsePayload - } - return &ipv4, nextParser -} - -func (l *IPv4) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *IPv4) length() int { - if l.IHL == nil { - return header.IPv4MinimumSize - } - return int(*l.IHL) -} - -// merge implements Layer.merge. -func (l *IPv4) merge(other Layer) error { - return mergeLayer(l, other) -} - -// IPv6 can construct and match an IPv6 encapsulation. -type IPv6 struct { - LayerBase - TrafficClass *uint8 - FlowLabel *uint32 - PayloadLength *uint16 - NextHeader *uint8 - HopLimit *uint8 - SrcAddr *tcpip.Address - DstAddr *tcpip.Address -} - -func (l *IPv6) String() string { - return stringLayer(l) -} - -// ToBytes implements Layer.ToBytes. -func (l *IPv6) ToBytes() ([]byte, error) { - b := make([]byte, header.IPv6MinimumSize) - h := header.IPv6(b) - fields := &header.IPv6Fields{ - HopLimit: 64, - } - if l.TrafficClass != nil { - fields.TrafficClass = *l.TrafficClass - } - if l.FlowLabel != nil { - fields.FlowLabel = *l.FlowLabel - } - if l.PayloadLength != nil { - fields.PayloadLength = *l.PayloadLength - } else { - for current := l.next(); current != nil; current = current.next() { - fields.PayloadLength += uint16(current.length()) - } - } - if l.NextHeader != nil { - fields.NextHeader = *l.NextHeader - } else { - switch n := l.next().(type) { - case *TCP: - fields.NextHeader = uint8(header.TCPProtocolNumber) - case *UDP: - fields.NextHeader = uint8(header.UDPProtocolNumber) - case *ICMPv6: - fields.NextHeader = uint8(header.ICMPv6ProtocolNumber) - case *IPv6HopByHopOptionsExtHdr: - fields.NextHeader = uint8(header.IPv6HopByHopOptionsExtHdrIdentifier) - case *IPv6DestinationOptionsExtHdr: - fields.NextHeader = uint8(header.IPv6DestinationOptionsExtHdrIdentifier) - default: - // TODO(b/150301488): Support more protocols as needed. - return nil, fmt.Errorf("ToBytes can't deduce the IPv6 header's next protocol: %#v", n) - } - } - if l.HopLimit != nil { - fields.HopLimit = *l.HopLimit - } - if l.SrcAddr != nil { - fields.SrcAddr = *l.SrcAddr - } - if l.DstAddr != nil { - fields.DstAddr = *l.DstAddr - } - h.Encode(fields) - return h, nil -} - -// nextIPv6PayloadParser finds the corresponding parser for nextHeader. -func nextIPv6PayloadParser(nextHeader uint8) layerParser { - switch tcpip.TransportProtocolNumber(nextHeader) { - case header.TCPProtocolNumber: - return parseTCP - case header.UDPProtocolNumber: - return parseUDP - case header.ICMPv6ProtocolNumber: - return parseICMPv6 - } - switch header.IPv6ExtensionHeaderIdentifier(nextHeader) { - case header.IPv6HopByHopOptionsExtHdrIdentifier: - return parseIPv6HopByHopOptionsExtHdr - case header.IPv6DestinationOptionsExtHdrIdentifier: - return parseIPv6DestinationOptionsExtHdr - } - return parsePayload -} - -// parseIPv6 parses the bytes assuming that they start with an ipv6 header and -// continues parsing further encapsulations. -func parseIPv6(b []byte) (Layer, layerParser) { - h := header.IPv6(b) - tos, flowLabel := h.TOS() - ipv6 := IPv6{ - TrafficClass: &tos, - FlowLabel: &flowLabel, - PayloadLength: Uint16(h.PayloadLength()), - NextHeader: Uint8(h.NextHeader()), - HopLimit: Uint8(h.HopLimit()), - SrcAddr: Address(h.SourceAddress()), - DstAddr: Address(h.DestinationAddress()), - } - nextParser := nextIPv6PayloadParser(h.NextHeader()) - return &ipv6, nextParser -} - -func (l *IPv6) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *IPv6) length() int { - return header.IPv6MinimumSize -} - -// merge overrides the values in l with the values from other but only in fields -// where the value is not nil. -func (l *IPv6) merge(other Layer) error { - return mergeLayer(l, other) -} - -// IPv6HopByHopOptionsExtHdr can construct and match an IPv6HopByHopOptions -// Extension Header. -type IPv6HopByHopOptionsExtHdr struct { - LayerBase - NextHeader *header.IPv6ExtensionHeaderIdentifier - Options []byte -} - -// IPv6DestinationOptionsExtHdr can construct and match an IPv6DestinationOptions -// Extension Header. -type IPv6DestinationOptionsExtHdr struct { - LayerBase - NextHeader *header.IPv6ExtensionHeaderIdentifier - Options []byte -} - -// ipv6OptionsExtHdrToBytes serializes an options extension header into bytes. -func ipv6OptionsExtHdrToBytes(nextHeader *header.IPv6ExtensionHeaderIdentifier, options []byte) []byte { - length := len(options) + 2 - bytes := make([]byte, length) - if nextHeader == nil { - bytes[0] = byte(header.IPv6NoNextHeaderIdentifier) - } else { - bytes[0] = byte(*nextHeader) - } - // ExtHdrLen field is the length of the extension header - // in 8-octet unit, ignoring the first 8 octets. - // https://tools.ietf.org/html/rfc2460#section-4.3 - // https://tools.ietf.org/html/rfc2460#section-4.6 - bytes[1] = uint8((length - 8) / 8) - copy(bytes[2:], options) - return bytes -} - -// IPv6ExtHdrIdent is a helper routine that allocates a new -// header.IPv6ExtensionHeaderIdentifier value to store v and returns a pointer -// to it. -func IPv6ExtHdrIdent(id header.IPv6ExtensionHeaderIdentifier) *header.IPv6ExtensionHeaderIdentifier { - return &id -} - -// ToBytes implements Layer.ToBytes -func (l *IPv6HopByHopOptionsExtHdr) ToBytes() ([]byte, error) { - return ipv6OptionsExtHdrToBytes(l.NextHeader, l.Options), nil -} - -// ToBytes implements Layer.ToBytes -func (l *IPv6DestinationOptionsExtHdr) ToBytes() ([]byte, error) { - return ipv6OptionsExtHdrToBytes(l.NextHeader, l.Options), nil -} - -// parseIPv6ExtHdr parses an IPv6 extension header and returns the NextHeader -// field, the rest of the payload and a parser function for the corresponding -// next extension header. -func parseIPv6ExtHdr(b []byte) (header.IPv6ExtensionHeaderIdentifier, []byte, layerParser) { - nextHeader := b[0] - // For HopByHop and Destination options extension headers, - // This field is the length of the extension header in - // 8-octet units, not including the first 8 octets. - // https://tools.ietf.org/html/rfc2460#section-4.3 - // https://tools.ietf.org/html/rfc2460#section-4.6 - length := b[1]*8 + 8 - data := b[2:length] - nextParser := nextIPv6PayloadParser(nextHeader) - return header.IPv6ExtensionHeaderIdentifier(nextHeader), data, nextParser -} - -// parseIPv6HopByHopOptionsExtHdr parses the bytes assuming that they start -// with an IPv6 HopByHop Options Extension Header. -func parseIPv6HopByHopOptionsExtHdr(b []byte) (Layer, layerParser) { - nextHeader, options, nextParser := parseIPv6ExtHdr(b) - return &IPv6HopByHopOptionsExtHdr{NextHeader: &nextHeader, Options: options}, nextParser -} - -// parseIPv6DestinationOptionsExtHdr parses the bytes assuming that they start -// with an IPv6 Destination Options Extension Header. -func parseIPv6DestinationOptionsExtHdr(b []byte) (Layer, layerParser) { - nextHeader, options, nextParser := parseIPv6ExtHdr(b) - return &IPv6DestinationOptionsExtHdr{NextHeader: &nextHeader, Options: options}, nextParser -} - -func (l *IPv6HopByHopOptionsExtHdr) length() int { - return len(l.Options) + 2 -} - -func (l *IPv6HopByHopOptionsExtHdr) match(other Layer) bool { - return equalLayer(l, other) -} - -// merge overrides the values in l with the values from other but only in fields -// where the value is not nil. -func (l *IPv6HopByHopOptionsExtHdr) merge(other Layer) error { - return mergeLayer(l, other) -} - -func (l *IPv6HopByHopOptionsExtHdr) String() string { - return stringLayer(l) -} - -func (l *IPv6DestinationOptionsExtHdr) length() int { - return len(l.Options) + 2 -} - -func (l *IPv6DestinationOptionsExtHdr) match(other Layer) bool { - return equalLayer(l, other) -} - -// merge overrides the values in l with the values from other but only in fields -// where the value is not nil. -func (l *IPv6DestinationOptionsExtHdr) merge(other Layer) error { - return mergeLayer(l, other) -} - -func (l *IPv6DestinationOptionsExtHdr) String() string { - return stringLayer(l) -} - -// ICMPv6 can construct and match an ICMPv6 encapsulation. -type ICMPv6 struct { - LayerBase - Type *header.ICMPv6Type - Code *byte - Checksum *uint16 - NDPPayload []byte -} - -func (l *ICMPv6) String() string { - // TODO(eyalsoha): Do something smarter here when *l.Type is ParameterProblem? - // We could parse the contents of the Payload as if it were an IPv6 packet. - return stringLayer(l) -} - -// ToBytes implements Layer.ToBytes. -func (l *ICMPv6) ToBytes() ([]byte, error) { - b := make([]byte, header.ICMPv6HeaderSize+len(l.NDPPayload)) - h := header.ICMPv6(b) - if l.Type != nil { - h.SetType(*l.Type) - } - if l.Code != nil { - h.SetCode(*l.Code) - } - copy(h.NDPPayload(), l.NDPPayload) - if l.Checksum != nil { - h.SetChecksum(*l.Checksum) - } else { - // It is possible that the ICMPv6 header does not follow the IPv6 header - // immediately, there could be one or more extension headers in between. - // We need to search forward to find the IPv6 header. - for prev := l.Prev(); prev != nil; prev = prev.Prev() { - if ipv6, ok := prev.(*IPv6); ok { - h.SetChecksum(header.ICMPv6Checksum(h, *ipv6.SrcAddr, *ipv6.DstAddr, buffer.VectorisedView{})) - break - } - } - } - return h, nil -} - -// ICMPv6Type is a helper routine that allocates a new ICMPv6Type value to store -// v and returns a pointer to it. -func ICMPv6Type(v header.ICMPv6Type) *header.ICMPv6Type { - return &v -} - -// Byte is a helper routine that allocates a new byte value to store -// v and returns a pointer to it. -func Byte(v byte) *byte { - return &v -} - -// parseICMPv6 parses the bytes assuming that they start with an ICMPv6 header. -func parseICMPv6(b []byte) (Layer, layerParser) { - h := header.ICMPv6(b) - icmpv6 := ICMPv6{ - Type: ICMPv6Type(h.Type()), - Code: Byte(h.Code()), - Checksum: Uint16(h.Checksum()), - NDPPayload: h.NDPPayload(), - } - return &icmpv6, nil -} - -func (l *ICMPv6) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *ICMPv6) length() int { - return header.ICMPv6HeaderSize + len(l.NDPPayload) -} - -// merge overrides the values in l with the values from other but only in fields -// where the value is not nil. -func (l *ICMPv6) merge(other Layer) error { - return mergeLayer(l, other) -} - -// ICMPv4Type is a helper routine that allocates a new header.ICMPv4Type value -// to store t and returns a pointer to it. -func ICMPv4Type(t header.ICMPv4Type) *header.ICMPv4Type { - return &t -} - -// ICMPv4 can construct and match an ICMPv4 encapsulation. -type ICMPv4 struct { - LayerBase - Type *header.ICMPv4Type - Code *uint8 - Checksum *uint16 -} - -func (l *ICMPv4) String() string { - return stringLayer(l) -} - -// ToBytes implements Layer.ToBytes. -func (l *ICMPv4) ToBytes() ([]byte, error) { - b := make([]byte, header.ICMPv4MinimumSize) - h := header.ICMPv4(b) - if l.Type != nil { - h.SetType(*l.Type) - } - if l.Code != nil { - h.SetCode(byte(*l.Code)) - } - if l.Checksum != nil { - h.SetChecksum(*l.Checksum) - return h, nil - } - payload, err := payload(l) - if err != nil { - return nil, err - } - h.SetChecksum(header.ICMPv4Checksum(h, payload)) - return h, nil -} - -// parseICMPv4 parses the bytes as an ICMPv4 header, returning a Layer and a -// parser for the encapsulated payload. -func parseICMPv4(b []byte) (Layer, layerParser) { - h := header.ICMPv4(b) - icmpv4 := ICMPv4{ - Type: ICMPv4Type(h.Type()), - Code: Uint8(h.Code()), - Checksum: Uint16(h.Checksum()), - } - return &icmpv4, parsePayload -} - -func (l *ICMPv4) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *ICMPv4) length() int { - return header.ICMPv4MinimumSize -} - -// merge overrides the values in l with the values from other but only in fields -// where the value is not nil. -func (l *ICMPv4) merge(other Layer) error { - return mergeLayer(l, other) -} - -// TCP can construct and match a TCP encapsulation. -type TCP struct { - LayerBase - SrcPort *uint16 - DstPort *uint16 - SeqNum *uint32 - AckNum *uint32 - DataOffset *uint8 - Flags *uint8 - WindowSize *uint16 - Checksum *uint16 - UrgentPointer *uint16 - Options []byte -} - -func (l *TCP) String() string { - return stringLayer(l) -} - -// ToBytes implements Layer.ToBytes. -func (l *TCP) ToBytes() ([]byte, error) { - b := make([]byte, l.length()) - h := header.TCP(b) - if l.SrcPort != nil { - h.SetSourcePort(*l.SrcPort) - } - if l.DstPort != nil { - h.SetDestinationPort(*l.DstPort) - } - if l.SeqNum != nil { - h.SetSequenceNumber(*l.SeqNum) - } - if l.AckNum != nil { - h.SetAckNumber(*l.AckNum) - } - if l.DataOffset != nil { - h.SetDataOffset(*l.DataOffset) - } else { - h.SetDataOffset(uint8(l.length())) - } - if l.Flags != nil { - h.SetFlags(*l.Flags) - } - if l.WindowSize != nil { - h.SetWindowSize(*l.WindowSize) - } else { - h.SetWindowSize(32768) - } - if l.UrgentPointer != nil { - h.SetUrgentPoiner(*l.UrgentPointer) - } - copy(b[header.TCPMinimumSize:], l.Options) - header.AddTCPOptionPadding(b[header.TCPMinimumSize:], len(l.Options)) - if l.Checksum != nil { - h.SetChecksum(*l.Checksum) - return h, nil - } - if err := setTCPChecksum(&h, l); err != nil { - return nil, err - } - return h, nil -} - -// totalLength returns the length of the provided layer and all following -// layers. -func totalLength(l Layer) int { - var totalLength int - for ; l != nil; l = l.next() { - totalLength += l.length() - } - return totalLength -} - -// payload returns a buffer.VectorisedView of l's payload. -func payload(l Layer) (buffer.VectorisedView, error) { - var payloadBytes buffer.VectorisedView - for current := l.next(); current != nil; current = current.next() { - payload, err := current.ToBytes() - if err != nil { - return buffer.VectorisedView{}, fmt.Errorf("can't get bytes for next header: %s", payload) - } - payloadBytes.AppendView(payload) - } - return payloadBytes, nil -} - -// layerChecksum calculates the checksum of the Layer header, including the -// peusdeochecksum of the layer before it and all the bytes after it. -func layerChecksum(l Layer, protoNumber tcpip.TransportProtocolNumber) (uint16, error) { - totalLength := uint16(totalLength(l)) - var xsum uint16 - switch p := l.Prev().(type) { - case *IPv4: - xsum = header.PseudoHeaderChecksum(protoNumber, *p.SrcAddr, *p.DstAddr, totalLength) - case *IPv6: - xsum = header.PseudoHeaderChecksum(protoNumber, *p.SrcAddr, *p.DstAddr, totalLength) - default: - // TODO(b/161246171): Support more protocols. - return 0, fmt.Errorf("checksum for protocol %d is not supported when previous layer is %T", protoNumber, p) - } - payloadBytes, err := payload(l) - if err != nil { - return 0, err - } - xsum = header.ChecksumVV(payloadBytes, xsum) - return xsum, nil -} - -// setTCPChecksum calculates the checksum of the TCP header and sets it in h. -func setTCPChecksum(h *header.TCP, tcp *TCP) error { - h.SetChecksum(0) - xsum, err := layerChecksum(tcp, header.TCPProtocolNumber) - if err != nil { - return err - } - h.SetChecksum(^h.CalculateChecksum(xsum)) - return nil -} - -// Uint32 is a helper routine that allocates a new -// uint32 value to store v and returns a pointer to it. -func Uint32(v uint32) *uint32 { - return &v -} - -// parseTCP parses the bytes assuming that they start with a tcp header and -// continues parsing further encapsulations. -func parseTCP(b []byte) (Layer, layerParser) { - h := header.TCP(b) - tcp := TCP{ - SrcPort: Uint16(h.SourcePort()), - DstPort: Uint16(h.DestinationPort()), - SeqNum: Uint32(h.SequenceNumber()), - AckNum: Uint32(h.AckNumber()), - DataOffset: Uint8(h.DataOffset()), - Flags: Uint8(h.Flags()), - WindowSize: Uint16(h.WindowSize()), - Checksum: Uint16(h.Checksum()), - UrgentPointer: Uint16(h.UrgentPointer()), - Options: b[header.TCPMinimumSize:h.DataOffset()], - } - return &tcp, parsePayload -} - -func (l *TCP) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *TCP) length() int { - if l.DataOffset == nil { - // TCP header including the options must end on a 32-bit - // boundary; the user could potentially give us a slice - // whose length is not a multiple of 4 bytes, so we have - // to do the alignment here. - optlen := (len(l.Options) + 3) & ^3 - return header.TCPMinimumSize + optlen - } - return int(*l.DataOffset) -} - -// merge implements Layer.merge. -func (l *TCP) merge(other Layer) error { - return mergeLayer(l, other) -} - -// UDP can construct and match a UDP encapsulation. -type UDP struct { - LayerBase - SrcPort *uint16 - DstPort *uint16 - Length *uint16 - Checksum *uint16 -} - -func (l *UDP) String() string { - return stringLayer(l) -} - -// ToBytes implements Layer.ToBytes. -func (l *UDP) ToBytes() ([]byte, error) { - b := make([]byte, header.UDPMinimumSize) - h := header.UDP(b) - if l.SrcPort != nil { - h.SetSourcePort(*l.SrcPort) - } - if l.DstPort != nil { - h.SetDestinationPort(*l.DstPort) - } - if l.Length != nil { - h.SetLength(*l.Length) - } else { - h.SetLength(uint16(totalLength(l))) - } - if l.Checksum != nil { - h.SetChecksum(*l.Checksum) - return h, nil - } - if err := setUDPChecksum(&h, l); err != nil { - return nil, err - } - return h, nil -} - -// setUDPChecksum calculates the checksum of the UDP header and sets it in h. -func setUDPChecksum(h *header.UDP, udp *UDP) error { - h.SetChecksum(0) - xsum, err := layerChecksum(udp, header.UDPProtocolNumber) - if err != nil { - return err - } - h.SetChecksum(^h.CalculateChecksum(xsum)) - return nil -} - -// parseUDP parses the bytes assuming that they start with a udp header and -// returns the parsed layer and the next parser to use. -func parseUDP(b []byte) (Layer, layerParser) { - h := header.UDP(b) - udp := UDP{ - SrcPort: Uint16(h.SourcePort()), - DstPort: Uint16(h.DestinationPort()), - Length: Uint16(h.Length()), - Checksum: Uint16(h.Checksum()), - } - return &udp, parsePayload -} - -func (l *UDP) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *UDP) length() int { - return header.UDPMinimumSize -} - -// merge implements Layer.merge. -func (l *UDP) merge(other Layer) error { - return mergeLayer(l, other) -} - -// Payload has bytes beyond OSI layer 4. -type Payload struct { - LayerBase - Bytes []byte -} - -func (l *Payload) String() string { - return stringLayer(l) -} - -// parsePayload parses the bytes assuming that they start with a payload and -// continue to the end. There can be no further encapsulations. -func parsePayload(b []byte) (Layer, layerParser) { - payload := Payload{ - Bytes: b, - } - return &payload, nil -} - -// ToBytes implements Layer.ToBytes. -func (l *Payload) ToBytes() ([]byte, error) { - return l.Bytes, nil -} - -// Length returns payload byte length. -func (l *Payload) Length() int { - return l.length() -} - -func (l *Payload) match(other Layer) bool { - return equalLayer(l, other) -} - -func (l *Payload) length() int { - return len(l.Bytes) -} - -// merge implements Layer.merge. -func (l *Payload) merge(other Layer) error { - return mergeLayer(l, other) -} - -// Layers is an array of Layer and supports similar functions to Layer. -type Layers []Layer - -// linkLayers sets the linked-list ponters in ls. -func (ls *Layers) linkLayers() { - for i, l := range *ls { - if i > 0 { - l.setPrev((*ls)[i-1]) - } else { - l.setPrev(nil) - } - if i+1 < len(*ls) { - l.setNext((*ls)[i+1]) - } else { - l.setNext(nil) - } - } -} - -// ToBytes converts the Layers into bytes. It creates a linked list of the Layer -// structs and then concatentates the output of ToBytes on each Layer. -func (ls *Layers) ToBytes() ([]byte, error) { - ls.linkLayers() - outBytes := []byte{} - for _, l := range *ls { - layerBytes, err := l.ToBytes() - if err != nil { - return nil, err - } - outBytes = append(outBytes, layerBytes...) - } - return outBytes, nil -} - -func (ls *Layers) match(other Layers) bool { - if len(*ls) > len(other) { - return false - } - for i, l := range *ls { - if !equalLayer(l, other[i]) { - return false - } - } - return true -} - -// layerDiff stores the diffs for each field along with the label for the Layer. -// If rows is nil, that means that there was no diff. -type layerDiff struct { - label string - rows []layerDiffRow -} - -// layerDiffRow stores the fields and corresponding values for two got and want -// layers. If the value was nil then the string stored is the empty string. -type layerDiffRow struct { - field, got, want string -} - -// diffLayer extracts all differing fields between two layers. -func diffLayer(got, want Layer) []layerDiffRow { - vGot := reflect.ValueOf(got).Elem() - vWant := reflect.ValueOf(want).Elem() - if vGot.Type() != vWant.Type() { - return nil - } - t := vGot.Type() - var result []layerDiffRow - for i := 0; i < t.NumField(); i++ { - t := t.Field(i) - if t.Anonymous { - // Ignore the LayerBase in the Layer struct. - continue - } - vGot := vGot.Field(i) - vWant := vWant.Field(i) - gotString := "" - if !vGot.IsNil() { - gotString = fmt.Sprint(reflect.Indirect(vGot)) - } - wantString := "" - if !vWant.IsNil() { - wantString = fmt.Sprint(reflect.Indirect(vWant)) - } - result = append(result, layerDiffRow{t.Name, gotString, wantString}) - } - return result -} - -// layerType returns a concise string describing the type of the Layer, like -// "TCP", or "IPv6". -func layerType(l Layer) string { - return reflect.TypeOf(l).Elem().Name() -} - -// diff compares Layers and returns a representation of the difference. Each -// Layer in the Layers is pairwise compared. If an element in either is nil, it -// is considered a match with the other Layer. If two Layers have differing -// types, they don't match regardless of the contents. If two Layers have the -// same type then the fields in the Layer are pairwise compared. Fields that are -// nil always match. Two non-nil fields only match if they point to equal -// values. diff returns an empty string if and only if *ls and other match. -func (ls *Layers) diff(other Layers) string { - var allDiffs []layerDiff - // Check the cases where one list is longer than the other, where one or both - // elements are nil, where the sides have different types, and where the sides - // have the same type. - for i := 0; i < len(*ls) || i < len(other); i++ { - if i >= len(*ls) { - // Matching ls against other where other is longer than ls. missing - // matches everything so we just include a label without any rows. Having - // no rows is a sign that there was no diff. - allDiffs = append(allDiffs, layerDiff{ - label: "missing matches " + layerType(other[i]), - }) - continue - } - - if i >= len(other) { - // Matching ls against other where ls is longer than other. missing - // matches everything so we just include a label without any rows. Having - // no rows is a sign that there was no diff. - allDiffs = append(allDiffs, layerDiff{ - label: layerType((*ls)[i]) + " matches missing", - }) - continue - } - - if (*ls)[i] == nil && other[i] == nil { - // Matching ls against other where both elements are nil. nil matches - // everything so we just include a label without any rows. Having no rows - // is a sign that there was no diff. - allDiffs = append(allDiffs, layerDiff{ - label: "nil matches nil", - }) - continue - } - - if (*ls)[i] == nil { - // Matching ls against other where the element in ls is nil. nil matches - // everything so we just include a label without any rows. Having no rows - // is a sign that there was no diff. - allDiffs = append(allDiffs, layerDiff{ - label: "nil matches " + layerType(other[i]), - }) - continue - } - - if other[i] == nil { - // Matching ls against other where the element in other is nil. nil - // matches everything so we just include a label without any rows. Having - // no rows is a sign that there was no diff. - allDiffs = append(allDiffs, layerDiff{ - label: layerType((*ls)[i]) + " matches nil", - }) - continue - } - - if reflect.TypeOf((*ls)[i]) == reflect.TypeOf(other[i]) { - // Matching ls against other where both elements have the same type. Match - // each field pairwise and only report a diff if there is a mismatch, - // which is only when both sides are non-nil and have differring values. - diff := diffLayer((*ls)[i], other[i]) - var layerDiffRows []layerDiffRow - for _, d := range diff { - if d.got == "" || d.want == "" || d.got == d.want { - continue - } - layerDiffRows = append(layerDiffRows, layerDiffRow{ - d.field, - d.got, - d.want, - }) - } - if len(layerDiffRows) > 0 { - allDiffs = append(allDiffs, layerDiff{ - label: layerType((*ls)[i]), - rows: layerDiffRows, - }) - } else { - allDiffs = append(allDiffs, layerDiff{ - label: layerType((*ls)[i]) + " matches " + layerType(other[i]), - // Having no rows is a sign that there was no diff. - }) - } - continue - } - // Neither side is nil and the types are different, so we'll display one - // side then the other. - allDiffs = append(allDiffs, layerDiff{ - label: layerType((*ls)[i]) + " doesn't match " + layerType(other[i]), - }) - diff := diffLayer((*ls)[i], (*ls)[i]) - layerDiffRows := []layerDiffRow{} - for _, d := range diff { - if len(d.got) == 0 { - continue - } - layerDiffRows = append(layerDiffRows, layerDiffRow{ - d.field, - d.got, - "", - }) - } - allDiffs = append(allDiffs, layerDiff{ - label: layerType((*ls)[i]), - rows: layerDiffRows, - }) - - layerDiffRows = []layerDiffRow{} - diff = diffLayer(other[i], other[i]) - for _, d := range diff { - if len(d.want) == 0 { - continue - } - layerDiffRows = append(layerDiffRows, layerDiffRow{ - d.field, - "", - d.want, - }) - } - allDiffs = append(allDiffs, layerDiff{ - label: layerType(other[i]), - rows: layerDiffRows, - }) - } - - output := "" - // These are for output formatting. - maxLabelLen, maxFieldLen, maxGotLen, maxWantLen := 0, 0, 0, 0 - foundOne := false - for _, l := range allDiffs { - if len(l.label) > maxLabelLen && len(l.rows) > 0 { - maxLabelLen = len(l.label) - } - if l.rows != nil { - foundOne = true - } - for _, r := range l.rows { - if len(r.field) > maxFieldLen { - maxFieldLen = len(r.field) - } - if l := len(fmt.Sprint(r.got)); l > maxGotLen { - maxGotLen = l - } - if l := len(fmt.Sprint(r.want)); l > maxWantLen { - maxWantLen = l - } - } - } - if !foundOne { - return "" - } - for _, l := range allDiffs { - if len(l.rows) == 0 { - output += "(" + l.label + ")\n" - continue - } - for i, r := range l.rows { - var label string - if i == 0 { - label = l.label + ":" - } - output += fmt.Sprintf( - "%*s %*s %*v %*v\n", - maxLabelLen+1, label, - maxFieldLen+1, r.field+":", - maxGotLen, r.got, - maxWantLen, r.want, - ) - } - } - return output -} - -// merge merges the other Layers into ls. If the other Layers is longer, those -// additional Layer structs are added to ls. The errors from merging are -// collected and returned. -func (ls *Layers) merge(other Layers) error { - var errs error - for i, o := range other { - if i < len(*ls) { - errs = multierr.Combine(errs, (*ls)[i].merge(o)) - } else { - *ls = append(*ls, o) - } - } - return errs -} |