func (this *SimpleAuthenticator) Open(buffer *alloc.Buffer) bool {
len := buffer.Len()
xtra := 4 - len%4
if xtra != 0 {
buffer.Slice(0, len+xtra)
}
xorbkd(buffer.Value)
if xtra != 0 {
buffer.Slice(0, len)
}
fnvHash := fnv.New32a()
fnvHash.Write(buffer.Value[4:])
if serial.BytesToUint32(buffer.Value[:4]) != fnvHash.Sum32() {
return false
}
length := serial.BytesToUint16(buffer.Value[4:6])
if buffer.Len()-6 != int(length) {
return false
}
buffer.SliceFrom(6)
return true
}
func (this *SimpleAuthenticator) Seal(buffer *alloc.Buffer) {
buffer.PrependUint16(uint16(buffer.Len()))
fnvHash := fnv.New32a()
fnvHash.Write(buffer.Value)
buffer.PrependHash(fnvHash)
len := buffer.Len()
xtra := 4 - len%4
if xtra != 0 {
buffer.Slice(0, len+xtra)
}
xorfwd(buffer.Value)
if xtra != 0 {
buffer.Slice(0, len)
}
}
func DecodeUDPPacket(user *protocol.User, payload *alloc.Buffer) (*protocol.RequestHeader, *alloc.Buffer, error) {
rawAccount, err := user.GetTypedAccount()
if err != nil {
return nil, nil, errors.New("Shadowsocks|UDP: Failed to parse account: " + err.Error())
}
account := rawAccount.(*ShadowsocksAccount)
ivLen := account.Cipher.IVSize()
iv := payload.Value[:ivLen]
payload.SliceFrom(ivLen)
stream, err := account.Cipher.NewDecodingStream(account.Key, iv)
if err != nil {
return nil, nil, errors.New("Shadowsocks|UDP: Failed to initialize decoding stream: " + err.Error())
}
stream.XORKeyStream(payload.Value, payload.Value)
authenticator := NewAuthenticator(HeaderKeyGenerator(account.Key, iv))
request := &protocol.RequestHeader{
Version: Version,
User: user,
Command: protocol.RequestCommandUDP,
}
addrType := (payload.Value[0] & 0x0F)
if (payload.Value[0] & 0x10) == 0x10 {
request.Option |= RequestOptionOneTimeAuth
}
if request.Option.Has(RequestOptionOneTimeAuth) {
payloadLen := payload.Len() - AuthSize
authBytes := payload.Value[payloadLen:]
actualAuth := authenticator.Authenticate(nil, payload.Value[0:payloadLen])
if !bytes.Equal(actualAuth, authBytes) {
return nil, nil, errors.New("Shadowsocks|UDP: Invalid OTA.")
}
payload.Slice(0, payloadLen)
}
payload.SliceFrom(1)
switch addrType {
case AddrTypeIPv4:
request.Address = v2net.IPAddress(payload.Value[:4])
payload.SliceFrom(4)
case AddrTypeIPv6:
request.Address = v2net.IPAddress(payload.Value[:16])
payload.SliceFrom(16)
case AddrTypeDomain:
domainLength := int(payload.Value[0])
request.Address = v2net.DomainAddress(string(payload.Value[1 : 1+domainLength]))
payload.SliceFrom(1 + domainLength)
default:
return nil, nil, errors.New("Shadowsocks|UDP: Unknown address type")
}
request.Port = v2net.PortFromBytes(payload.Value[:2])
payload.SliceFrom(2)
return request, payload, nil
}
func (this *AuthChunkReader) Read() (*alloc.Buffer, error) {
var buffer *alloc.Buffer
if this.last != nil {
buffer = this.last
this.last = nil
} else {
buffer = alloc.NewBufferWithSize(4096).Clear()
}
if this.chunkLength == -1 {
for buffer.Len() < 6 {
_, err := buffer.FillFrom(this.reader)
if err != nil {
buffer.Release()
return nil, io.ErrUnexpectedEOF
}
}
length := serial.BytesToUint16(buffer.Value[:2])
this.chunkLength = int(length) - 4
this.validator = NewValidator(serial.BytesToUint32(buffer.Value[2:6]))
buffer.SliceFrom(6)
if buffer.Len() < this.chunkLength && this.chunkLength <= 2048 {
_, err := buffer.FillFrom(this.reader)
if err != nil {
buffer.Release()
return nil, io.ErrUnexpectedEOF
}
}
} else if buffer.Len() < this.chunkLength {
_, err := buffer.FillFrom(this.reader)
if err != nil {
buffer.Release()
return nil, io.ErrUnexpectedEOF
}
}
if this.chunkLength == 0 {
buffer.Release()
return nil, io.EOF
}
if buffer.Len() < this.chunkLength {
this.validator.Consume(buffer.Value)
this.chunkLength -= buffer.Len()
} else {
this.validator.Consume(buffer.Value[:this.chunkLength])
if !this.validator.Validate() {
buffer.Release()
return nil, transport.ErrCorruptedPacket
}
leftLength := buffer.Len() - this.chunkLength
if leftLength > 0 {
this.last = alloc.NewBufferWithSize(leftLength + 4096).Clear()
this.last.Append(buffer.Value[this.chunkLength:])
buffer.Slice(0, this.chunkLength)
}
this.chunkLength = -1
this.validator = nil
}
return buffer, nil
}