[VOL-1349] EPON OLT adapter (package B)
Change-Id: I634ef62c53813dcf4456f54948f13e06358e263c
diff --git a/vendor/github.com/google/gopacket/packet.go b/vendor/github.com/google/gopacket/packet.go
new file mode 100644
index 0000000..3a7c4b3
--- /dev/null
+++ b/vendor/github.com/google/gopacket/packet.go
@@ -0,0 +1,864 @@
+// Copyright 2012 Google, Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+package gopacket
+
+import (
+ "bytes"
+ "encoding/hex"
+ "errors"
+ "fmt"
+ "io"
+ "net"
+ "os"
+ "reflect"
+ "runtime/debug"
+ "strings"
+ "syscall"
+ "time"
+)
+
+// CaptureInfo provides standardized information about a packet captured off
+// the wire or read from a file.
+type CaptureInfo struct {
+ // Timestamp is the time the packet was captured, if that is known.
+ Timestamp time.Time
+ // CaptureLength is the total number of bytes read off of the wire.
+ CaptureLength int
+ // Length is the size of the original packet. Should always be >=
+ // CaptureLength.
+ Length int
+ // InterfaceIndex
+ InterfaceIndex int
+ // The packet source can place ancillary data of various types here.
+ // For example, the afpacket source can report the VLAN of captured
+ // packets this way.
+ AncillaryData []interface{}
+}
+
+// PacketMetadata contains metadata for a packet.
+type PacketMetadata struct {
+ CaptureInfo
+ // Truncated is true if packet decoding logic detects that there are fewer
+ // bytes in the packet than are detailed in various headers (for example, if
+ // the number of bytes in the IPv4 contents/payload is less than IPv4.Length).
+ // This is also set automatically for packets captured off the wire if
+ // CaptureInfo.CaptureLength < CaptureInfo.Length.
+ Truncated bool
+}
+
+// Packet is the primary object used by gopacket. Packets are created by a
+// Decoder's Decode call. A packet is made up of a set of Data, which
+// is broken into a number of Layers as it is decoded.
+type Packet interface {
+ //// Functions for outputting the packet as a human-readable string:
+ //// ------------------------------------------------------------------
+ // String returns a human-readable string representation of the packet.
+ // It uses LayerString on each layer to output the layer.
+ String() string
+ // Dump returns a verbose human-readable string representation of the packet,
+ // including a hex dump of all layers. It uses LayerDump on each layer to
+ // output the layer.
+ Dump() string
+
+ //// Functions for accessing arbitrary packet layers:
+ //// ------------------------------------------------------------------
+ // Layers returns all layers in this packet, computing them as necessary
+ Layers() []Layer
+ // Layer returns the first layer in this packet of the given type, or nil
+ Layer(LayerType) Layer
+ // LayerClass returns the first layer in this packet of the given class,
+ // or nil.
+ LayerClass(LayerClass) Layer
+
+ //// Functions for accessing specific types of packet layers. These functions
+ //// return the first layer of each type found within the packet.
+ //// ------------------------------------------------------------------
+ // LinkLayer returns the first link layer in the packet
+ LinkLayer() LinkLayer
+ // NetworkLayer returns the first network layer in the packet
+ NetworkLayer() NetworkLayer
+ // TransportLayer returns the first transport layer in the packet
+ TransportLayer() TransportLayer
+ // ApplicationLayer returns the first application layer in the packet
+ ApplicationLayer() ApplicationLayer
+ // ErrorLayer is particularly useful, since it returns nil if the packet
+ // was fully decoded successfully, and non-nil if an error was encountered
+ // in decoding and the packet was only partially decoded. Thus, its output
+ // can be used to determine if the entire packet was able to be decoded.
+ ErrorLayer() ErrorLayer
+
+ //// Functions for accessing data specific to the packet:
+ //// ------------------------------------------------------------------
+ // Data returns the set of bytes that make up this entire packet.
+ Data() []byte
+ // Metadata returns packet metadata associated with this packet.
+ Metadata() *PacketMetadata
+}
+
+// packet contains all the information we need to fulfill the Packet interface,
+// and its two "subclasses" (yes, no such thing in Go, bear with me),
+// eagerPacket and lazyPacket, provide eager and lazy decoding logic around the
+// various functions needed to access this information.
+type packet struct {
+ // data contains the entire packet data for a packet
+ data []byte
+ // initialLayers is space for an initial set of layers already created inside
+ // the packet.
+ initialLayers [6]Layer
+ // layers contains each layer we've already decoded
+ layers []Layer
+ // last is the last layer added to the packet
+ last Layer
+ // metadata is the PacketMetadata for this packet
+ metadata PacketMetadata
+
+ decodeOptions DecodeOptions
+
+ // Pointers to the various important layers
+ link LinkLayer
+ network NetworkLayer
+ transport TransportLayer
+ application ApplicationLayer
+ failure ErrorLayer
+}
+
+func (p *packet) SetTruncated() {
+ p.metadata.Truncated = true
+}
+
+func (p *packet) SetLinkLayer(l LinkLayer) {
+ if p.link == nil {
+ p.link = l
+ }
+}
+
+func (p *packet) SetNetworkLayer(l NetworkLayer) {
+ if p.network == nil {
+ p.network = l
+ }
+}
+
+func (p *packet) SetTransportLayer(l TransportLayer) {
+ if p.transport == nil {
+ p.transport = l
+ }
+}
+
+func (p *packet) SetApplicationLayer(l ApplicationLayer) {
+ if p.application == nil {
+ p.application = l
+ }
+}
+
+func (p *packet) SetErrorLayer(l ErrorLayer) {
+ if p.failure == nil {
+ p.failure = l
+ }
+}
+
+func (p *packet) AddLayer(l Layer) {
+ p.layers = append(p.layers, l)
+ p.last = l
+}
+
+func (p *packet) DumpPacketData() {
+ fmt.Fprint(os.Stderr, p.packetDump())
+ os.Stderr.Sync()
+}
+
+func (p *packet) Metadata() *PacketMetadata {
+ return &p.metadata
+}
+
+func (p *packet) Data() []byte {
+ return p.data
+}
+
+func (p *packet) DecodeOptions() *DecodeOptions {
+ return &p.decodeOptions
+}
+
+func (p *packet) addFinalDecodeError(err error, stack []byte) {
+ fail := &DecodeFailure{err: err, stack: stack}
+ if p.last == nil {
+ fail.data = p.data
+ } else {
+ fail.data = p.last.LayerPayload()
+ }
+ p.AddLayer(fail)
+ p.SetErrorLayer(fail)
+}
+
+func (p *packet) recoverDecodeError() {
+ if !p.decodeOptions.SkipDecodeRecovery {
+ if r := recover(); r != nil {
+ p.addFinalDecodeError(fmt.Errorf("%v", r), debug.Stack())
+ }
+ }
+}
+
+// LayerString outputs an individual layer as a string. The layer is output
+// in a single line, with no trailing newline. This function is specifically
+// designed to do the right thing for most layers... it follows the following
+// rules:
+// * If the Layer has a String function, just output that.
+// * Otherwise, output all exported fields in the layer, recursing into
+// exported slices and structs.
+// NOTE: This is NOT THE SAME AS fmt's "%#v". %#v will output both exported
+// and unexported fields... many times packet layers contain unexported stuff
+// that would just mess up the output of the layer, see for example the
+// Payload layer and it's internal 'data' field, which contains a large byte
+// array that would really mess up formatting.
+func LayerString(l Layer) string {
+ return fmt.Sprintf("%v\t%s", l.LayerType(), layerString(reflect.ValueOf(l), false, false))
+}
+
+// Dumper dumps verbose information on a value. If a layer type implements
+// Dumper, then its LayerDump() string will include the results in its output.
+type Dumper interface {
+ Dump() string
+}
+
+// LayerDump outputs a very verbose string representation of a layer. Its
+// output is a concatenation of LayerString(l) and hex.Dump(l.LayerContents()).
+// It contains newlines and ends with a newline.
+func LayerDump(l Layer) string {
+ var b bytes.Buffer
+ b.WriteString(LayerString(l))
+ b.WriteByte('\n')
+ if d, ok := l.(Dumper); ok {
+ dump := d.Dump()
+ if dump != "" {
+ b.WriteString(dump)
+ if dump[len(dump)-1] != '\n' {
+ b.WriteByte('\n')
+ }
+ }
+ }
+ b.WriteString(hex.Dump(l.LayerContents()))
+ return b.String()
+}
+
+// layerString outputs, recursively, a layer in a "smart" way. See docs for
+// LayerString for more details.
+//
+// Params:
+// i - value to write out
+// anonymous: if we're currently recursing an anonymous member of a struct
+// writeSpace: if we've already written a value in a struct, and need to
+// write a space before writing more. This happens when we write various
+// anonymous values, and need to keep writing more.
+func layerString(v reflect.Value, anonymous bool, writeSpace bool) string {
+ // Let String() functions take precedence.
+ if v.CanInterface() {
+ if s, ok := v.Interface().(fmt.Stringer); ok {
+ return s.String()
+ }
+ }
+ // Reflect, and spit out all the exported fields as key=value.
+ switch v.Type().Kind() {
+ case reflect.Interface, reflect.Ptr:
+ if v.IsNil() {
+ return "nil"
+ }
+ r := v.Elem()
+ return layerString(r, anonymous, writeSpace)
+ case reflect.Struct:
+ var b bytes.Buffer
+ typ := v.Type()
+ if !anonymous {
+ b.WriteByte('{')
+ }
+ for i := 0; i < v.NumField(); i++ {
+ // Check if this is upper-case.
+ ftype := typ.Field(i)
+ f := v.Field(i)
+ if ftype.Anonymous {
+ anonStr := layerString(f, true, writeSpace)
+ writeSpace = writeSpace || anonStr != ""
+ b.WriteString(anonStr)
+ } else if ftype.PkgPath == "" { // exported
+ if writeSpace {
+ b.WriteByte(' ')
+ }
+ writeSpace = true
+ fmt.Fprintf(&b, "%s=%s", typ.Field(i).Name, layerString(f, false, writeSpace))
+ }
+ }
+ if !anonymous {
+ b.WriteByte('}')
+ }
+ return b.String()
+ case reflect.Slice:
+ var b bytes.Buffer
+ b.WriteByte('[')
+ if v.Len() > 4 {
+ fmt.Fprintf(&b, "..%d..", v.Len())
+ } else {
+ for j := 0; j < v.Len(); j++ {
+ if j != 0 {
+ b.WriteString(", ")
+ }
+ b.WriteString(layerString(v.Index(j), false, false))
+ }
+ }
+ b.WriteByte(']')
+ return b.String()
+ }
+ return fmt.Sprintf("%v", v.Interface())
+}
+
+const (
+ longBytesLength = 128
+)
+
+// LongBytesGoString returns a string representation of the byte slice shortened
+// using the format '<type>{<truncated slice> ... (<n> bytes)}' if it
+// exceeds a predetermined length. Can be used to avoid filling the display with
+// very long byte strings.
+func LongBytesGoString(buf []byte) string {
+ if len(buf) < longBytesLength {
+ return fmt.Sprintf("%#v", buf)
+ }
+ s := fmt.Sprintf("%#v", buf[:longBytesLength-1])
+ s = strings.TrimSuffix(s, "}")
+ return fmt.Sprintf("%s ... (%d bytes)}", s, len(buf))
+}
+
+func baseLayerString(value reflect.Value) string {
+ t := value.Type()
+ content := value.Field(0)
+ c := make([]byte, content.Len())
+ for i := range c {
+ c[i] = byte(content.Index(i).Uint())
+ }
+ payload := value.Field(1)
+ p := make([]byte, payload.Len())
+ for i := range p {
+ p[i] = byte(payload.Index(i).Uint())
+ }
+ return fmt.Sprintf("%s{Contents:%s, Payload:%s}", t.String(),
+ LongBytesGoString(c),
+ LongBytesGoString(p))
+}
+
+func layerGoString(i interface{}, b *bytes.Buffer) {
+ if s, ok := i.(fmt.GoStringer); ok {
+ b.WriteString(s.GoString())
+ return
+ }
+
+ var v reflect.Value
+ var ok bool
+ if v, ok = i.(reflect.Value); !ok {
+ v = reflect.ValueOf(i)
+ }
+ switch v.Kind() {
+ case reflect.Ptr, reflect.Interface:
+ if v.Kind() == reflect.Ptr {
+ b.WriteByte('&')
+ }
+ layerGoString(v.Elem().Interface(), b)
+ case reflect.Struct:
+ t := v.Type()
+ b.WriteString(t.String())
+ b.WriteByte('{')
+ for i := 0; i < v.NumField(); i++ {
+ if i > 0 {
+ b.WriteString(", ")
+ }
+ if t.Field(i).Name == "BaseLayer" {
+ fmt.Fprintf(b, "BaseLayer:%s", baseLayerString(v.Field(i)))
+ } else if v.Field(i).Kind() == reflect.Struct {
+ fmt.Fprintf(b, "%s:", t.Field(i).Name)
+ layerGoString(v.Field(i), b)
+ } else if v.Field(i).Kind() == reflect.Ptr {
+ b.WriteByte('&')
+ layerGoString(v.Field(i), b)
+ } else {
+ fmt.Fprintf(b, "%s:%#v", t.Field(i).Name, v.Field(i))
+ }
+ }
+ b.WriteByte('}')
+ default:
+ fmt.Fprintf(b, "%#v", i)
+ }
+}
+
+// LayerGoString returns a representation of the layer in Go syntax,
+// taking care to shorten "very long" BaseLayer byte slices
+func LayerGoString(l Layer) string {
+ b := new(bytes.Buffer)
+ layerGoString(l, b)
+ return b.String()
+}
+
+func (p *packet) packetString() string {
+ var b bytes.Buffer
+ fmt.Fprintf(&b, "PACKET: %d bytes", len(p.Data()))
+ if p.metadata.Truncated {
+ b.WriteString(", truncated")
+ }
+ if p.metadata.Length > 0 {
+ fmt.Fprintf(&b, ", wire length %d cap length %d", p.metadata.Length, p.metadata.CaptureLength)
+ }
+ if !p.metadata.Timestamp.IsZero() {
+ fmt.Fprintf(&b, " @ %v", p.metadata.Timestamp)
+ }
+ b.WriteByte('\n')
+ for i, l := range p.layers {
+ fmt.Fprintf(&b, "- Layer %d (%02d bytes) = %s\n", i+1, len(l.LayerContents()), LayerString(l))
+ }
+ return b.String()
+}
+
+func (p *packet) packetDump() string {
+ var b bytes.Buffer
+ fmt.Fprintf(&b, "-- FULL PACKET DATA (%d bytes) ------------------------------------\n%s", len(p.data), hex.Dump(p.data))
+ for i, l := range p.layers {
+ fmt.Fprintf(&b, "--- Layer %d ---\n%s", i+1, LayerDump(l))
+ }
+ return b.String()
+}
+
+// eagerPacket is a packet implementation that does eager decoding. Upon
+// initial construction, it decodes all the layers it can from packet data.
+// eagerPacket implements Packet and PacketBuilder.
+type eagerPacket struct {
+ packet
+}
+
+var errNilDecoder = errors.New("NextDecoder passed nil decoder, probably an unsupported decode type")
+
+func (p *eagerPacket) NextDecoder(next Decoder) error {
+ if next == nil {
+ return errNilDecoder
+ }
+ if p.last == nil {
+ return errors.New("NextDecoder called, but no layers added yet")
+ }
+ d := p.last.LayerPayload()
+ if len(d) == 0 {
+ return nil
+ }
+ // Since we're eager, immediately call the next decoder.
+ return next.Decode(d, p)
+}
+func (p *eagerPacket) initialDecode(dec Decoder) {
+ defer p.recoverDecodeError()
+ err := dec.Decode(p.data, p)
+ if err != nil {
+ p.addFinalDecodeError(err, nil)
+ }
+}
+func (p *eagerPacket) LinkLayer() LinkLayer {
+ return p.link
+}
+func (p *eagerPacket) NetworkLayer() NetworkLayer {
+ return p.network
+}
+func (p *eagerPacket) TransportLayer() TransportLayer {
+ return p.transport
+}
+func (p *eagerPacket) ApplicationLayer() ApplicationLayer {
+ return p.application
+}
+func (p *eagerPacket) ErrorLayer() ErrorLayer {
+ return p.failure
+}
+func (p *eagerPacket) Layers() []Layer {
+ return p.layers
+}
+func (p *eagerPacket) Layer(t LayerType) Layer {
+ for _, l := range p.layers {
+ if l.LayerType() == t {
+ return l
+ }
+ }
+ return nil
+}
+func (p *eagerPacket) LayerClass(lc LayerClass) Layer {
+ for _, l := range p.layers {
+ if lc.Contains(l.LayerType()) {
+ return l
+ }
+ }
+ return nil
+}
+func (p *eagerPacket) String() string { return p.packetString() }
+func (p *eagerPacket) Dump() string { return p.packetDump() }
+
+// lazyPacket does lazy decoding on its packet data. On construction it does
+// no initial decoding. For each function call, it decodes only as many layers
+// as are necessary to compute the return value for that function.
+// lazyPacket implements Packet and PacketBuilder.
+type lazyPacket struct {
+ packet
+ next Decoder
+}
+
+func (p *lazyPacket) NextDecoder(next Decoder) error {
+ if next == nil {
+ return errNilDecoder
+ }
+ p.next = next
+ return nil
+}
+func (p *lazyPacket) decodeNextLayer() {
+ if p.next == nil {
+ return
+ }
+ d := p.data
+ if p.last != nil {
+ d = p.last.LayerPayload()
+ }
+ next := p.next
+ p.next = nil
+ // We've just set p.next to nil, so if we see we have no data, this should be
+ // the final call we get to decodeNextLayer if we return here.
+ if len(d) == 0 {
+ return
+ }
+ defer p.recoverDecodeError()
+ err := next.Decode(d, p)
+ if err != nil {
+ p.addFinalDecodeError(err, nil)
+ }
+}
+func (p *lazyPacket) LinkLayer() LinkLayer {
+ for p.link == nil && p.next != nil {
+ p.decodeNextLayer()
+ }
+ return p.link
+}
+func (p *lazyPacket) NetworkLayer() NetworkLayer {
+ for p.network == nil && p.next != nil {
+ p.decodeNextLayer()
+ }
+ return p.network
+}
+func (p *lazyPacket) TransportLayer() TransportLayer {
+ for p.transport == nil && p.next != nil {
+ p.decodeNextLayer()
+ }
+ return p.transport
+}
+func (p *lazyPacket) ApplicationLayer() ApplicationLayer {
+ for p.application == nil && p.next != nil {
+ p.decodeNextLayer()
+ }
+ return p.application
+}
+func (p *lazyPacket) ErrorLayer() ErrorLayer {
+ for p.failure == nil && p.next != nil {
+ p.decodeNextLayer()
+ }
+ return p.failure
+}
+func (p *lazyPacket) Layers() []Layer {
+ for p.next != nil {
+ p.decodeNextLayer()
+ }
+ return p.layers
+}
+func (p *lazyPacket) Layer(t LayerType) Layer {
+ for _, l := range p.layers {
+ if l.LayerType() == t {
+ return l
+ }
+ }
+ numLayers := len(p.layers)
+ for p.next != nil {
+ p.decodeNextLayer()
+ for _, l := range p.layers[numLayers:] {
+ if l.LayerType() == t {
+ return l
+ }
+ }
+ numLayers = len(p.layers)
+ }
+ return nil
+}
+func (p *lazyPacket) LayerClass(lc LayerClass) Layer {
+ for _, l := range p.layers {
+ if lc.Contains(l.LayerType()) {
+ return l
+ }
+ }
+ numLayers := len(p.layers)
+ for p.next != nil {
+ p.decodeNextLayer()
+ for _, l := range p.layers[numLayers:] {
+ if lc.Contains(l.LayerType()) {
+ return l
+ }
+ }
+ numLayers = len(p.layers)
+ }
+ return nil
+}
+func (p *lazyPacket) String() string { p.Layers(); return p.packetString() }
+func (p *lazyPacket) Dump() string { p.Layers(); return p.packetDump() }
+
+// DecodeOptions tells gopacket how to decode a packet.
+type DecodeOptions struct {
+ // Lazy decoding decodes the minimum number of layers needed to return data
+ // for a packet at each function call. Be careful using this with concurrent
+ // packet processors, as each call to packet.* could mutate the packet, and
+ // two concurrent function calls could interact poorly.
+ Lazy bool
+ // NoCopy decoding doesn't copy its input buffer into storage that's owned by
+ // the packet. If you can guarantee that the bytes underlying the slice
+ // passed into NewPacket aren't going to be modified, this can be faster. If
+ // there's any chance that those bytes WILL be changed, this will invalidate
+ // your packets.
+ NoCopy bool
+ // SkipDecodeRecovery skips over panic recovery during packet decoding.
+ // Normally, when packets decode, if a panic occurs, that panic is captured
+ // by a recover(), and a DecodeFailure layer is added to the packet detailing
+ // the issue. If this flag is set, panics are instead allowed to continue up
+ // the stack.
+ SkipDecodeRecovery bool
+ // DecodeStreamsAsDatagrams enables routing of application-level layers in the TCP
+ // decoder. If true, we should try to decode layers after TCP in single packets.
+ // This is disabled by default because the reassembly package drives the decoding
+ // of TCP payload data after reassembly.
+ DecodeStreamsAsDatagrams bool
+}
+
+// Default decoding provides the safest (but slowest) method for decoding
+// packets. It eagerly processes all layers (so it's concurrency-safe) and it
+// copies its input buffer upon creation of the packet (so the packet remains
+// valid if the underlying slice is modified. Both of these take time,
+// though, so beware. If you can guarantee that the packet will only be used
+// by one goroutine at a time, set Lazy decoding. If you can guarantee that
+// the underlying slice won't change, set NoCopy decoding.
+var Default = DecodeOptions{}
+
+// Lazy is a DecodeOptions with just Lazy set.
+var Lazy = DecodeOptions{Lazy: true}
+
+// NoCopy is a DecodeOptions with just NoCopy set.
+var NoCopy = DecodeOptions{NoCopy: true}
+
+// DecodeStreamsAsDatagrams is a DecodeOptions with just DecodeStreamsAsDatagrams set.
+var DecodeStreamsAsDatagrams = DecodeOptions{DecodeStreamsAsDatagrams: true}
+
+// NewPacket creates a new Packet object from a set of bytes. The
+// firstLayerDecoder tells it how to interpret the first layer from the bytes,
+// future layers will be generated from that first layer automatically.
+func NewPacket(data []byte, firstLayerDecoder Decoder, options DecodeOptions) Packet {
+ if !options.NoCopy {
+ dataCopy := make([]byte, len(data))
+ copy(dataCopy, data)
+ data = dataCopy
+ }
+ if options.Lazy {
+ p := &lazyPacket{
+ packet: packet{data: data, decodeOptions: options},
+ next: firstLayerDecoder,
+ }
+ p.layers = p.initialLayers[:0]
+ // Crazy craziness:
+ // If the following return statemet is REMOVED, and Lazy is FALSE, then
+ // eager packet processing becomes 17% FASTER. No, there is no logical
+ // explanation for this. However, it's such a hacky micro-optimization that
+ // we really can't rely on it. It appears to have to do with the size the
+ // compiler guesses for this function's stack space, since one symptom is
+ // that with the return statement in place, we more than double calls to
+ // runtime.morestack/runtime.lessstack. We'll hope the compiler gets better
+ // over time and we get this optimization for free. Until then, we'll have
+ // to live with slower packet processing.
+ return p
+ }
+ p := &eagerPacket{
+ packet: packet{data: data, decodeOptions: options},
+ }
+ p.layers = p.initialLayers[:0]
+ p.initialDecode(firstLayerDecoder)
+ return p
+}
+
+// PacketDataSource is an interface for some source of packet data. Users may
+// create their own implementations, or use the existing implementations in
+// gopacket/pcap (libpcap, allows reading from live interfaces or from
+// pcap files) or gopacket/pfring (PF_RING, allows reading from live
+// interfaces).
+type PacketDataSource interface {
+ // ReadPacketData returns the next packet available from this data source.
+ // It returns:
+ // data: The bytes of an individual packet.
+ // ci: Metadata about the capture
+ // err: An error encountered while reading packet data. If err != nil,
+ // then data/ci will be ignored.
+ ReadPacketData() (data []byte, ci CaptureInfo, err error)
+}
+
+// ConcatFinitePacketDataSources returns a PacketDataSource that wraps a set
+// of internal PacketDataSources, each of which will stop with io.EOF after
+// reading a finite number of packets. The returned PacketDataSource will
+// return all packets from the first finite source, followed by all packets from
+// the second, etc. Once all finite sources have returned io.EOF, the returned
+// source will as well.
+func ConcatFinitePacketDataSources(pds ...PacketDataSource) PacketDataSource {
+ c := concat(pds)
+ return &c
+}
+
+type concat []PacketDataSource
+
+func (c *concat) ReadPacketData() (data []byte, ci CaptureInfo, err error) {
+ for len(*c) > 0 {
+ data, ci, err = (*c)[0].ReadPacketData()
+ if err == io.EOF {
+ *c = (*c)[1:]
+ continue
+ }
+ return
+ }
+ return nil, CaptureInfo{}, io.EOF
+}
+
+// ZeroCopyPacketDataSource is an interface to pull packet data from sources
+// that allow data to be returned without copying to a user-controlled buffer.
+// It's very similar to PacketDataSource, except that the caller must be more
+// careful in how the returned buffer is handled.
+type ZeroCopyPacketDataSource interface {
+ // ZeroCopyReadPacketData returns the next packet available from this data source.
+ // It returns:
+ // data: The bytes of an individual packet. Unlike with
+ // PacketDataSource's ReadPacketData, the slice returned here points
+ // to a buffer owned by the data source. In particular, the bytes in
+ // this buffer may be changed by future calls to
+ // ZeroCopyReadPacketData. Do not use the returned buffer after
+ // subsequent ZeroCopyReadPacketData calls.
+ // ci: Metadata about the capture
+ // err: An error encountered while reading packet data. If err != nil,
+ // then data/ci will be ignored.
+ ZeroCopyReadPacketData() (data []byte, ci CaptureInfo, err error)
+}
+
+// PacketSource reads in packets from a PacketDataSource, decodes them, and
+// returns them.
+//
+// There are currently two different methods for reading packets in through
+// a PacketSource:
+//
+// Reading With Packets Function
+//
+// This method is the most convenient and easiest to code, but lacks
+// flexibility. Packets returns a 'chan Packet', then asynchronously writes
+// packets into that channel. Packets uses a blocking channel, and closes
+// it if an io.EOF is returned by the underlying PacketDataSource. All other
+// PacketDataSource errors are ignored and discarded.
+// for packet := range packetSource.Packets() {
+// ...
+// }
+//
+// Reading With NextPacket Function
+//
+// This method is the most flexible, and exposes errors that may be
+// encountered by the underlying PacketDataSource. It's also the fastest
+// in a tight loop, since it doesn't have the overhead of a channel
+// read/write. However, it requires the user to handle errors, most
+// importantly the io.EOF error in cases where packets are being read from
+// a file.
+// for {
+// packet, err := packetSource.NextPacket()
+// if err == io.EOF {
+// break
+// } else if err != nil {
+// log.Println("Error:", err)
+// continue
+// }
+// handlePacket(packet) // Do something with each packet.
+// }
+type PacketSource struct {
+ source PacketDataSource
+ decoder Decoder
+ // DecodeOptions is the set of options to use for decoding each piece
+ // of packet data. This can/should be changed by the user to reflect the
+ // way packets should be decoded.
+ DecodeOptions
+ c chan Packet
+}
+
+// NewPacketSource creates a packet data source.
+func NewPacketSource(source PacketDataSource, decoder Decoder) *PacketSource {
+ return &PacketSource{
+ source: source,
+ decoder: decoder,
+ }
+}
+
+// NextPacket returns the next decoded packet from the PacketSource. On error,
+// it returns a nil packet and a non-nil error.
+func (p *PacketSource) NextPacket() (Packet, error) {
+ data, ci, err := p.source.ReadPacketData()
+ if err != nil {
+ return nil, err
+ }
+ packet := NewPacket(data, p.decoder, p.DecodeOptions)
+ m := packet.Metadata()
+ m.CaptureInfo = ci
+ m.Truncated = m.Truncated || ci.CaptureLength < ci.Length
+ return packet, nil
+}
+
+// packetsToChannel reads in all packets from the packet source and sends them
+// to the given channel. This routine terminates when a non-temporary error
+// is returned by NextPacket().
+func (p *PacketSource) packetsToChannel() {
+ defer close(p.c)
+ for {
+ packet, err := p.NextPacket()
+ if err == nil {
+ p.c <- packet
+ continue
+ }
+
+ // Immediately retry for temporary network errors
+ if nerr, ok := err.(net.Error); ok && nerr.Temporary() {
+ continue
+ }
+
+ // Immediately retry for EAGAIN
+ if err == syscall.EAGAIN {
+ continue
+ }
+
+ // Immediately break for known unrecoverable errors
+ if err == io.EOF || err == io.ErrUnexpectedEOF ||
+ err == io.ErrNoProgress || err == io.ErrClosedPipe || err == io.ErrShortBuffer ||
+ err == syscall.EBADF ||
+ strings.Contains(err.Error(), "use of closed file") {
+ break
+ }
+
+ // Sleep briefly and try again
+ time.Sleep(time.Millisecond * time.Duration(5))
+ }
+}
+
+// Packets returns a channel of packets, allowing easy iterating over
+// packets. Packets will be asynchronously read in from the underlying
+// PacketDataSource and written to the returned channel. If the underlying
+// PacketDataSource returns an io.EOF error, the channel will be closed.
+// If any other error is encountered, it is ignored.
+//
+// for packet := range packetSource.Packets() {
+// handlePacket(packet) // Do something with each packet.
+// }
+//
+// If called more than once, returns the same channel.
+func (p *PacketSource) Packets() chan Packet {
+ if p.c == nil {
+ p.c = make(chan Packet, 1000)
+ go p.packetsToChannel()
+ }
+ return p.c
+}