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-rw-r--r--test/packetimpact/testbench/layers.go710
1 files changed, 710 insertions, 0 deletions
diff --git a/test/packetimpact/testbench/layers.go b/test/packetimpact/testbench/layers.go
new file mode 100644
index 000000000..5ce324f0d
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+++ b/test/packetimpact/testbench/layers.go
@@ -0,0 +1,710 @@
+// 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"
+ "github.com/imdario/mergo"
+ "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
+}
+
+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 other in layer. Any non-nil value in other overrides the
+// corresponding value in layer. If other is nil, no action is performed.
+func mergeLayer(layer, other Layer) error {
+ if other == nil {
+ return nil
+ }
+ return mergo.Merge(layer, other, mergo.WithOverride)
+}
+
+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)
+}
+
+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
+ default:
+ // TODO(b/150301488): Support more protocols, like IPv6.
+ 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
+ default:
+ // Assume that the rest is a payload.
+ nextParser = parsePayload
+ }
+ return &ether, nextParser
+}
+
+func (l *Ether) match(other Layer) bool {
+ return equalLayer(l, other)
+}
+
+func (l *Ether) length() int {
+ return header.EthernetMinimumSize
+}
+
+// merge overrides the values in l with the values from other but only in fields
+// where the value is not nil.
+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)
+}
+
+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)
+ 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
+ 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 overrides the values in l with the values from other but only in fields
+// where the value is not nil.
+func (l *IPv4) 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
+}
+
+func (l *TCP) String() string {
+ return stringLayer(l)
+}
+
+func (l *TCP) toBytes() ([]byte, error) {
+ b := make([]byte, header.TCPMinimumSize)
+ 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)
+ }
+ 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
+}
+
+// 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 s := l.prev().(type) {
+ case *IPv4:
+ xsum = header.PseudoHeaderChecksum(protoNumber, *s.SrcAddr, *s.DstAddr, totalLength)
+ default:
+ // TODO(b/150301488): Support more protocols, like IPv6.
+ return 0, fmt.Errorf("can't get src and dst addr from previous layer: %#v", s)
+ }
+ var payloadBytes buffer.VectorisedView
+ for current := l.next(); current != nil; current = current.next() {
+ payload, err := current.toBytes()
+ if err != nil {
+ return 0, fmt.Errorf("can't get bytes for next header: %s", payload)
+ }
+ payloadBytes.AppendView(payload)
+ }
+ 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()),
+ }
+ return &tcp, parsePayload
+}
+
+func (l *TCP) match(other Layer) bool {
+ return equalLayer(l, other)
+}
+
+func (l *TCP) length() int {
+ if l.DataOffset == nil {
+ return header.TCPMinimumSize
+ }
+ return int(*l.DataOffset)
+}
+
+// merge overrides the values in l with the values from other but only in fields
+// where the value is not nil.
+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)
+}
+
+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 {
+ if l.Length == nil {
+ return header.UDPMinimumSize
+ }
+ return int(*l.Length)
+}
+
+// merge overrides the values in l with the values from other but only in fields
+// where the value is not nil.
+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
+}
+
+func (l *Payload) toBytes() ([]byte, error) {
+ return l.Bytes, nil
+}
+
+func (l *Payload) match(other Layer) bool {
+ return equalLayer(l, other)
+}
+
+func (l *Payload) length() int {
+ return len(l.Bytes)
+}
+
+// merge overrides the values in l with the values from other but only in fields
+// where the value is not nil.
+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)
+ }
+ }
+}
+
+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
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-11 16:56:29 +0000