[VOL-1349] EPON OLT adapter (package B)
Change-Id: I634ef62c53813dcf4456f54948f13e06358e263c
diff --git a/vendor/github.com/google/gopacket/writer.go b/vendor/github.com/google/gopacket/writer.go
new file mode 100644
index 0000000..5d303dc
--- /dev/null
+++ b/vendor/github.com/google/gopacket/writer.go
@@ -0,0 +1,232 @@
+// 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 (
+ "fmt"
+)
+
+// SerializableLayer allows its implementations to be written out as a set of bytes,
+// so those bytes may be sent on the wire or otherwise used by the caller.
+// SerializableLayer is implemented by certain Layer types, and can be encoded to
+// bytes using the LayerWriter object.
+type SerializableLayer interface {
+ // SerializeTo writes this layer to a slice, growing that slice if necessary
+ // to make it fit the layer's data.
+ // Args:
+ // b: SerializeBuffer to write this layer on to. When called, b.Bytes()
+ // is the payload this layer should wrap, if any. Note that this
+ // layer can either prepend itself (common), append itself
+ // (uncommon), or both (sometimes padding or footers are required at
+ // the end of packet data). It's also possible (though probably very
+ // rarely needed) to overwrite any bytes in the current payload.
+ // After this call, b.Bytes() should return the byte encoding of
+ // this layer wrapping the original b.Bytes() payload.
+ // opts: options to use while writing out data.
+ // Returns:
+ // error if a problem was encountered during encoding. If an error is
+ // returned, the bytes in data should be considered invalidated, and
+ // not used.
+ //
+ // SerializeTo calls SHOULD entirely ignore LayerContents and
+ // LayerPayload. It just serializes based on struct fields, neither
+ // modifying nor using contents/payload.
+ SerializeTo(b SerializeBuffer, opts SerializeOptions) error
+ // LayerType returns the type of the layer that is being serialized to the buffer
+ LayerType() LayerType
+}
+
+// SerializeOptions provides options for behaviors that SerializableLayers may want to
+// implement.
+type SerializeOptions struct {
+ // FixLengths determines whether, during serialization, layers should fix
+ // the values for any length field that depends on the payload.
+ FixLengths bool
+ // ComputeChecksums determines whether, during serialization, layers
+ // should recompute checksums based on their payloads.
+ ComputeChecksums bool
+}
+
+// SerializeBuffer is a helper used by gopacket for writing out packet layers.
+// SerializeBuffer starts off as an empty []byte. Subsequent calls to PrependBytes
+// return byte slices before the current Bytes(), AppendBytes returns byte
+// slices after.
+//
+// Byte slices returned by PrependBytes/AppendBytes are NOT zero'd out, so if
+// you want to make sure they're all zeros, set them as such.
+//
+// SerializeBuffer is specifically designed to handle packet writing, where unlike
+// with normal writes it's easier to start writing at the inner-most layer and
+// work out, meaning that we often need to prepend bytes. This runs counter to
+// typical writes to byte slices using append(), where we only write at the end
+// of the buffer.
+//
+// It can be reused via Clear. Note, however, that a Clear call will invalidate the
+// byte slices returned by any previous Bytes() call (the same buffer is
+// reused).
+//
+// 1) Reusing a write buffer is generally much faster than creating a new one,
+// and with the default implementation it avoids additional memory allocations.
+// 2) If a byte slice from a previous Bytes() call will continue to be used,
+// it's better to create a new SerializeBuffer.
+//
+// The Clear method is specifically designed to minimize memory allocations for
+// similar later workloads on the SerializeBuffer. IE: if you make a set of
+// Prepend/Append calls, then clear, then make the same calls with the same
+// sizes, the second round (and all future similar rounds) shouldn't allocate
+// any new memory.
+type SerializeBuffer interface {
+ // Bytes returns the contiguous set of bytes collected so far by Prepend/Append
+ // calls. The slice returned by Bytes will be modified by future Clear calls,
+ // so if you're planning on clearing this SerializeBuffer, you may want to copy
+ // Bytes somewhere safe first.
+ Bytes() []byte
+ // PrependBytes returns a set of bytes which prepends the current bytes in this
+ // buffer. These bytes start in an indeterminate state, so they should be
+ // overwritten by the caller. The caller must only call PrependBytes if they
+ // know they're going to immediately overwrite all bytes returned.
+ PrependBytes(num int) ([]byte, error)
+ // AppendBytes returns a set of bytes which appends the current bytes in this
+ // buffer. These bytes start in an indeterminate state, so they should be
+ // overwritten by the caller. The caller must only call AppendBytes if they
+ // know they're going to immediately overwrite all bytes returned.
+ AppendBytes(num int) ([]byte, error)
+ // Clear resets the SerializeBuffer to a new, empty buffer. After a call to clear,
+ // the byte slice returned by any previous call to Bytes() for this buffer
+ // should be considered invalidated.
+ Clear() error
+ // Layers returns all the Layers that have been successfully serialized into this buffer
+ // already.
+ Layers() []LayerType
+ // PushLayer adds the current Layer to the list of Layers that have been serialized
+ // into this buffer.
+ PushLayer(LayerType)
+}
+
+type serializeBuffer struct {
+ data []byte
+ start int
+ prepended, appended int
+ layers []LayerType
+}
+
+// NewSerializeBuffer creates a new instance of the default implementation of
+// the SerializeBuffer interface.
+func NewSerializeBuffer() SerializeBuffer {
+ return &serializeBuffer{}
+}
+
+// NewSerializeBufferExpectedSize creates a new buffer for serialization, optimized for an
+// expected number of bytes prepended/appended. This tends to decrease the
+// number of memory allocations made by the buffer during writes.
+func NewSerializeBufferExpectedSize(expectedPrependLength, expectedAppendLength int) SerializeBuffer {
+ return &serializeBuffer{
+ data: make([]byte, expectedPrependLength, expectedPrependLength+expectedAppendLength),
+ start: expectedPrependLength,
+ prepended: expectedPrependLength,
+ appended: expectedAppendLength,
+ }
+}
+
+func (w *serializeBuffer) Bytes() []byte {
+ return w.data[w.start:]
+}
+
+func (w *serializeBuffer) PrependBytes(num int) ([]byte, error) {
+ if num < 0 {
+ panic("num < 0")
+ }
+ if w.start < num {
+ toPrepend := w.prepended
+ if toPrepend < num {
+ toPrepend = num
+ }
+ w.prepended += toPrepend
+ length := cap(w.data) + toPrepend
+ newData := make([]byte, length)
+ newStart := w.start + toPrepend
+ copy(newData[newStart:], w.data[w.start:])
+ w.start = newStart
+ w.data = newData[:toPrepend+len(w.data)]
+ }
+ w.start -= num
+ return w.data[w.start : w.start+num], nil
+}
+
+func (w *serializeBuffer) AppendBytes(num int) ([]byte, error) {
+ if num < 0 {
+ panic("num < 0")
+ }
+ initialLength := len(w.data)
+ if cap(w.data)-initialLength < num {
+ toAppend := w.appended
+ if toAppend < num {
+ toAppend = num
+ }
+ w.appended += toAppend
+ newData := make([]byte, cap(w.data)+toAppend)
+ copy(newData[w.start:], w.data[w.start:])
+ w.data = newData[:initialLength]
+ }
+ // Grow the buffer. We know it'll be under capacity given above.
+ w.data = w.data[:initialLength+num]
+ return w.data[initialLength:], nil
+}
+
+func (w *serializeBuffer) Clear() error {
+ w.start = w.prepended
+ w.data = w.data[:w.start]
+ w.layers = w.layers[:0]
+ return nil
+}
+
+func (w *serializeBuffer) Layers() []LayerType {
+ return w.layers
+}
+
+func (w *serializeBuffer) PushLayer(l LayerType) {
+ w.layers = append(w.layers, l)
+}
+
+// SerializeLayers clears the given write buffer, then writes all layers into it so
+// they correctly wrap each other. Note that by clearing the buffer, it
+// invalidates all slices previously returned by w.Bytes()
+//
+// Example:
+// buf := gopacket.NewSerializeBuffer()
+// opts := gopacket.SerializeOptions{}
+// gopacket.SerializeLayers(buf, opts, a, b, c)
+// firstPayload := buf.Bytes() // contains byte representation of a(b(c))
+// gopacket.SerializeLayers(buf, opts, d, e, f)
+// secondPayload := buf.Bytes() // contains byte representation of d(e(f)). firstPayload is now invalidated, since the SerializeLayers call Clears buf.
+func SerializeLayers(w SerializeBuffer, opts SerializeOptions, layers ...SerializableLayer) error {
+ w.Clear()
+ for i := len(layers) - 1; i >= 0; i-- {
+ layer := layers[i]
+ err := layer.SerializeTo(w, opts)
+ if err != nil {
+ return err
+ }
+ w.PushLayer(layer.LayerType())
+ }
+ return nil
+}
+
+// SerializePacket is a convenience function that calls SerializeLayers
+// on packet's Layers().
+// It returns an error if one of the packet layers is not a SerializableLayer.
+func SerializePacket(buf SerializeBuffer, opts SerializeOptions, packet Packet) error {
+ sls := []SerializableLayer{}
+ for _, layer := range packet.Layers() {
+ sl, ok := layer.(SerializableLayer)
+ if !ok {
+ return fmt.Errorf("layer %s is not serializable", layer.LayerType().String())
+ }
+ sls = append(sls, sl)
+ }
+ return SerializeLayers(buf, opts, sls...)
+}