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//
// Copyright (c) 2017 anygone contributors (see AUTHORS file)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * Neither the name of anygone nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
package satp
import (
"encoding/binary"
"errors"
"io"
)
//
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | sequence number | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
// | sender ID | MUX | |
// +#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+ |
// | | payload type | | |
// | +-------------------------------+ | |
// | | .... payload ... | |
// | | +-------------------------------+ |
// | | | padding (OPT) | pad count(OPT)| |
// +#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+#+-+
// | : authentication tag (RECOMMENDED) : |
// | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
// | |
// +- Encrypted Portion Authenticated Portion ---+
//
const (
PACKET_BUFFER_SIZE = 16384
)
var (
ErrTooShort = errors.New("packet is too short")
)
type PlainPacket struct {
buffer [PACKET_BUFFER_SIZE]byte
header []byte
payload []byte
}
func NewPlainPacket() (pp *PlainPacket) {
pp = &PlainPacket{}
pp.header = pp.buffer[:2:2]
pp.payload = pp.buffer[2:2]
return
}
func (pp *PlainPacket) SetPayloadType(payloadType uint16) {
binary.BigEndian.PutUint16(pp.header, payloadType)
return
}
func (pp *PlainPacket) GetPayloadType() (payloadType uint16) {
return binary.BigEndian.Uint16(pp.header)
}
func (pp *PlainPacket) getPacket() (data []byte) {
return pp.buffer[:len(pp.header)+len(pp.payload)]
}
func (pp *PlainPacket) ReadFrom(r io.Reader) (int64, error) {
n, err := r.Read(pp.payload[:cap(pp.payload)])
if err != nil && err != io.EOF {
return 0, err
}
pp.payload = pp.payload[:n]
return int64(n), nil
}
func (pp *PlainPacket) WriteTo(w io.Writer) (int64, error) {
n, err := w.Write(pp.payload)
return int64(n), err
}
type EncryptedPacket struct {
buffer [PACKET_BUFFER_SIZE]byte
header []byte
payload []byte
authTag []byte
}
func NewEncryptedPacket() (ep *EncryptedPacket) {
ep = &EncryptedPacket{}
ep.header = ep.buffer[:8:8]
ep.payload = ep.buffer[8:8]
ep.authTag = nil
return
}
func (ep *EncryptedPacket) SetAuthTagLength(length int) error {
total := len(ep.payload) + len(ep.authTag)
if length <= 0 {
ep.payload = ep.payload[:total]
ep.authTag = nil
return nil
}
if length > (total - 2) { // minimal payload length = 2 (Payload Type)
return ErrTooShort
}
ep.payload = ep.payload[:total-length]
ep.authTag = ep.buffer[len(ep.header)+len(ep.payload) : len(ep.header)+total]
return nil
}
func (ep *EncryptedPacket) GetAuthTagLength() int {
return len(ep.authTag)
}
func (ep *EncryptedPacket) SetSequenceNumber(sequenceNumber uint32) {
binary.BigEndian.PutUint32(ep.header[:4], sequenceNumber)
return
}
func (ep *EncryptedPacket) GetSequenceNumber() (sequenceNumber uint32) {
return binary.BigEndian.Uint32(ep.header[:4])
}
func (ep *EncryptedPacket) SetSenderID(senderID uint16) {
binary.BigEndian.PutUint16(ep.header[4:6], senderID)
return
}
func (ep *EncryptedPacket) GetSenderID() (senderID uint16) {
return binary.BigEndian.Uint16(ep.header[4:6])
}
func (ep *EncryptedPacket) SetMux(mux uint16) {
binary.BigEndian.PutUint16(ep.header[6:8], mux)
return
}
func (ep *EncryptedPacket) GetMux() (mux uint16) {
return binary.BigEndian.Uint16(ep.header[6:8])
}
func (ep *EncryptedPacket) ReadFrom(r io.Reader) (int64, error) {
n, err := r.Read(ep.buffer[:])
if err != nil && err != io.EOF {
return 0, err
}
if n < len(ep.header)+2+len(ep.authTag) { // minimal payload length = 2 (Payload Type)
return 0, ErrTooShort
}
ep.payload = ep.payload[:n-len(ep.header)]
err = ep.SetAuthTagLength(len(ep.authTag))
return int64(n), err
}
func (ep *EncryptedPacket) getPacket() (data []byte) {
return ep.buffer[:len(ep.header)+len(ep.payload)+len(ep.authTag)]
}
func (ep *EncryptedPacket) WriteTo(w io.Writer) (int64, error) {
n, err := w.Write(ep.getPacket())
return int64(n), err
}
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