From 3f1edad4e6ba0a7876750aea55507fae14d8badf Mon Sep 17 00:00:00 2001
From: Milan Lenco <milan.lenco@pantheon.tech>
Date: Wed, 11 Oct 2017 16:40:58 +0200
Subject: ODPM 266: Go-libmemif + 2 examples.

Change-Id: Icdb9b9eb2314eff6c96afe7996fcf2728291de4a
Signed-off-by: Milan Lenco <milan.lenco@pantheon.tech>
---
 vendor/github.com/google/gopacket/layers/llc.go | 146 ++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 vendor/github.com/google/gopacket/layers/llc.go

(limited to 'vendor/github.com/google/gopacket/layers/llc.go')

diff --git a/vendor/github.com/google/gopacket/layers/llc.go b/vendor/github.com/google/gopacket/layers/llc.go
new file mode 100644
index 0000000..59453fe
--- /dev/null
+++ b/vendor/github.com/google/gopacket/layers/llc.go
@@ -0,0 +1,146 @@
+// 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 layers
+
+import (
+	"encoding/binary"
+	"errors"
+
+	"github.com/google/gopacket"
+)
+
+// LLC is the layer used for 802.2 Logical Link Control headers.
+// See http://standards.ieee.org/getieee802/download/802.2-1998.pdf
+type LLC struct {
+	BaseLayer
+	DSAP    uint8
+	IG      bool // true means group, false means individual
+	SSAP    uint8
+	CR      bool // true means response, false means command
+	Control uint16
+}
+
+// LayerType returns gopacket.LayerTypeLLC.
+func (l *LLC) LayerType() gopacket.LayerType { return LayerTypeLLC }
+
+// SNAP is used inside LLC.  See
+// http://standards.ieee.org/getieee802/download/802-2001.pdf.
+// From http://en.wikipedia.org/wiki/Subnetwork_Access_Protocol:
+//  "[T]he Subnetwork Access Protocol (SNAP) is a mechanism for multiplexing,
+//  on networks using IEEE 802.2 LLC, more protocols than can be distinguished
+//  by the 8-bit 802.2 Service Access Point (SAP) fields."
+type SNAP struct {
+	BaseLayer
+	OrganizationalCode []byte
+	Type               EthernetType
+}
+
+// LayerType returns gopacket.LayerTypeSNAP.
+func (s *SNAP) LayerType() gopacket.LayerType { return LayerTypeSNAP }
+
+func decodeLLC(data []byte, p gopacket.PacketBuilder) error {
+	l := &LLC{
+		DSAP:    data[0] & 0xFE,
+		IG:      data[0]&0x1 != 0,
+		SSAP:    data[1] & 0xFE,
+		CR:      data[1]&0x1 != 0,
+		Control: uint16(data[2]),
+	}
+	if l.Control&0x1 == 0 || l.Control&0x3 == 0x1 {
+		l.Control = l.Control<<8 | uint16(data[3])
+		l.Contents = data[:4]
+		l.Payload = data[4:]
+	} else {
+		l.Contents = data[:3]
+		l.Payload = data[3:]
+	}
+	p.AddLayer(l)
+	switch {
+	case l.DSAP == 0xAA && l.SSAP == 0xAA:
+		return p.NextDecoder(LayerTypeSNAP)
+	case l.DSAP == 0x42 && l.SSAP == 0x42:
+		return p.NextDecoder(LayerTypeSTP)
+	}
+	return p.NextDecoder(gopacket.DecodeUnknown)
+}
+
+func decodeSNAP(data []byte, p gopacket.PacketBuilder) error {
+	s := &SNAP{
+		OrganizationalCode: data[:3],
+		Type:               EthernetType(binary.BigEndian.Uint16(data[3:5])),
+		BaseLayer:          BaseLayer{data[:5], data[5:]},
+	}
+	p.AddLayer(s)
+	// BUG(gconnell):  When decoding SNAP, we treat the SNAP type as an Ethernet
+	// type.  This may not actually be an ethernet type in all cases,
+	// depending on the organizational code.  Right now, we don't check.
+	return p.NextDecoder(s.Type)
+}
+
+// SerializeTo writes the serialized form of this layer into the
+// SerializationBuffer, implementing gopacket.SerializableLayer.
+// See the docs for gopacket.SerializableLayer for more info.
+func (l *LLC) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	var ig_flag, cr_flag byte
+	var length int
+
+	if l.Control&0xFF00 != 0 {
+		length = 4
+	} else {
+		length = 3
+	}
+
+	if l.DSAP&0x1 != 0 {
+		return errors.New("DSAP value invalid, should not include IG flag bit")
+	}
+
+	if l.SSAP&0x1 != 0 {
+		return errors.New("SSAP value invalid, should not include CR flag bit")
+	}
+
+	if buf, err := b.PrependBytes(length); err != nil {
+		return err
+	} else {
+		ig_flag = 0
+		if l.IG {
+			ig_flag = 0x1
+		}
+
+		cr_flag = 0
+		if l.CR {
+			cr_flag = 0x1
+		}
+
+		buf[0] = l.DSAP + ig_flag
+		buf[1] = l.SSAP + cr_flag
+
+		if length == 4 {
+			buf[2] = uint8(l.Control >> 8)
+			buf[3] = uint8(l.Control)
+		} else {
+			buf[2] = uint8(l.Control)
+		}
+	}
+
+	return nil
+}
+
+// SerializeTo writes the serialized form of this layer into the
+// SerializationBuffer, implementing gopacket.SerializableLayer.
+// See the docs for gopacket.SerializableLayer for more info.
+func (s *SNAP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	if buf, err := b.PrependBytes(5); err != nil {
+		return err
+	} else {
+		buf[0] = s.OrganizationalCode[0]
+		buf[1] = s.OrganizationalCode[1]
+		buf[2] = s.OrganizationalCode[2]
+		binary.BigEndian.PutUint16(buf[3:5], uint16(s.Type))
+	}
+
+	return nil
+}
-- 
cgit 1.2.3-korg