Vender add

vender/github.com/ccding/go-stun/stun/packet.go

@@ -0,0 +1,129 @@
+// Copyright 2013, Cong Ding. All rights reserved.
+//
+// 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.
+//
+// Author: Cong Ding <dinggnu@gmail.com>
+
+package stun
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"errors"
+)
+
+type packet struct {
+	types      uint16
+	length     uint16
+	transID    []byte // 4 bytes magic cookie + 12 bytes transaction id
+	attributes []attribute
+}
+
+func newPacket() (*packet, error) {
+	v := new(packet)
+	v.transID = make([]byte, 16)
+	binary.BigEndian.PutUint32(v.transID[:4], magicCookie)
+	_, err := rand.Read(v.transID[4:])
+	if err != nil {
+		return nil, err
+	}
+	v.attributes = make([]attribute, 0, 10)
+	v.length = 0
+	return v, nil
+}
+
+func newPacketFromBytes(packetBytes []byte) (*packet, error) {
+	if len(packetBytes) < 24 {
+		return nil, errors.New("Received data length too short.")
+	}
+	pkt := new(packet)
+	pkt.types = binary.BigEndian.Uint16(packetBytes[0:2])
+	pkt.length = binary.BigEndian.Uint16(packetBytes[2:4])
+	pkt.transID = packetBytes[4:20]
+	pkt.attributes = make([]attribute, 0, 10)
+	for pos := uint16(20); pos < uint16(len(packetBytes)); {
+		types := binary.BigEndian.Uint16(packetBytes[pos : pos+2])
+		length := binary.BigEndian.Uint16(packetBytes[pos+2 : pos+4])
+		if pos+4+length > uint16(len(packetBytes)) {
+			return nil, errors.New("Received data format mismatch.")
+		}
+		value := packetBytes[pos+4 : pos+4+length]
+		attribute := newAttribute(types, value)
+		pkt.addAttribute(*attribute)
+		pos += align(length) + 4
+	}
+	return pkt, nil
+}
+
+func (v *packet) addAttribute(a attribute) {
+	v.attributes = append(v.attributes, a)
+	v.length += align(a.length) + 4
+}
+
+func (v *packet) bytes() []byte {
+	packetBytes := make([]byte, 4)
+	binary.BigEndian.PutUint16(packetBytes[0:2], v.types)
+	binary.BigEndian.PutUint16(packetBytes[2:4], v.length)
+	packetBytes = append(packetBytes, v.transID...)
+	for _, a := range v.attributes {
+		buf := make([]byte, 2)
+		binary.BigEndian.PutUint16(buf, a.types)
+		packetBytes = append(packetBytes, buf...)
+		binary.BigEndian.PutUint16(buf, a.length)
+		packetBytes = append(packetBytes, buf...)
+		packetBytes = append(packetBytes, a.value...)
+	}
+	return packetBytes
+}
+
+func (v *packet) getSourceAddr() *Host {
+	return v.getRawAddr(attributeSourceAddress)
+}
+
+func (v *packet) getMappedAddr() *Host {
+	return v.getRawAddr(attributeMappedAddress)
+}
+
+func (v *packet) getChangedAddr() *Host {
+	return v.getRawAddr(attributeChangedAddress)
+}
+
+func (v *packet) getOtherAddr() *Host {
+	return v.getRawAddr(attributeOtherAddress)
+}
+
+func (v *packet) getRawAddr(attribute uint16) *Host {
+	for _, a := range v.attributes {
+		if a.types == attribute {
+			return a.rawAddr()
+		}
+	}
+	return nil
+}
+
+func (v *packet) getXorMappedAddr() *Host {
+	addr := v.getXorAddr(attributeXorMappedAddress)
+	if addr == nil {
+		addr = v.getXorAddr(attributeXorMappedAddressExp)
+	}
+	return addr
+}
+
+func (v *packet) getXorAddr(attribute uint16) *Host {
+	for _, a := range v.attributes {
+		if a.types == attribute {
+			return a.xorAddr(v.transID)
+		}
+	}
+	return nil
+}