package mux import ( "v2ray.com/core/common/buf" "v2ray.com/core/common/net" "v2ray.com/core/common/serial" ) type SessionStatus byte const ( SessionStatusNew SessionStatus = 0x01 SessionStatusKeep SessionStatus = 0x02 SessionStatusEnd SessionStatus = 0x03 SessionStatusKeepAlive SessionStatus = 0x04 ) type Option byte const ( OptionData Option = 0x01 ) func (o Option) Has(x Option) bool { return (o & x) == x } func (o *Option) Add(x Option) { *o = (*o | x) } func (o *Option) Clear(x Option) { *o = (*o & (^x)) } type TargetNetwork byte const ( TargetNetworkTCP TargetNetwork = 0x01 TargetNetworkUDP TargetNetwork = 0x02 ) type AddressType byte const ( AddressTypeIPv4 AddressType = 0x01 AddressTypeDomain AddressType = 0x02 AddressTypeIPv6 AddressType = 0x03 ) /* Frame format 2 bytes - length 2 bytes - session id 1 bytes - status 1 bytes - option 1 byte - network 2 bytes - port n bytes - address */ type FrameMetadata struct { SessionID uint16 SessionStatus SessionStatus Target net.Destination Option Option } func (f FrameMetadata) AsSupplier() buf.Supplier { return func(b []byte) (int, error) { lengthBytes := b b = serial.Uint16ToBytes(uint16(0), b[:0]) // place holder for length b = serial.Uint16ToBytes(f.SessionID, b) b = append(b, byte(f.SessionStatus), byte(f.Option)) length := 4 if f.SessionStatus == SessionStatusNew { switch f.Target.Network { case net.Network_TCP: b = append(b, byte(TargetNetworkTCP)) case net.Network_UDP: b = append(b, byte(TargetNetworkUDP)) } length++ b = serial.Uint16ToBytes(f.Target.Port.Value(), b) length += 2 addr := f.Target.Address switch addr.Family() { case net.AddressFamilyIPv4: b = append(b, byte(AddressTypeIPv4)) b = append(b, addr.IP()...) length += 5 case net.AddressFamilyIPv6: b = append(b, byte(AddressTypeIPv6)) b = append(b, addr.IP()...) length += 17 case net.AddressFamilyDomain: nDomain := len(addr.Domain()) b = append(b, byte(AddressTypeDomain), byte(nDomain)) b = append(b, addr.Domain()...) length += nDomain + 2 } } serial.Uint16ToBytes(uint16(length), lengthBytes[:0]) return length + 2, nil } } func ReadFrameFrom(b []byte) (*FrameMetadata, error) { if len(b) < 4 { return nil, newError("insufficient buffer: ", len(b)) } f := &FrameMetadata{ SessionID: serial.BytesToUint16(b[:2]), SessionStatus: SessionStatus(b[2]), Option: Option(b[3]), } b = b[4:] if f.SessionStatus == SessionStatusNew { network := TargetNetwork(b[0]) port := net.PortFromBytes(b[1:3]) addrType := AddressType(b[3]) b = b[4:] var addr net.Address switch addrType { case AddressTypeIPv4: addr = net.IPAddress(b[0:4]) b = b[4:] case AddressTypeIPv6: addr = net.IPAddress(b[0:16]) b = b[16:] case AddressTypeDomain: nDomain := int(b[0]) addr = net.DomainAddress(string(b[1 : 1+nDomain])) b = b[nDomain+1:] default: return nil, newError("unknown address type: ", addrType) } switch network { case TargetNetworkTCP: f.Target = net.TCPDestination(addr, port) case TargetNetworkUDP: f.Target = net.UDPDestination(addr, port) default: return nil, newError("unknown network type: ", network) } } return f, nil }