package tls import ( "context" "github.com/v2fly/v2ray-core/v4/common" "github.com/v2fly/v2ray-core/v4/common/dice" ) // DTLS writes header as DTLS. See https://tools.ietf.org/html/rfc6347 type DTLS struct { epoch uint16 length uint16 sequence uint32 } // Size implements PacketHeader. func (*DTLS) Size() int32 { return 1 + 2 + 2 + 6 + 2 } // Serialize implements PacketHeader. func (d *DTLS) Serialize(b []byte) { b[0] = 23 // application data b[1] = 254 b[2] = 253 b[3] = byte(d.epoch >> 8) b[4] = byte(d.epoch) b[5] = 0 b[6] = 0 b[7] = byte(d.sequence >> 24) b[8] = byte(d.sequence >> 16) b[9] = byte(d.sequence >> 8) b[10] = byte(d.sequence) d.sequence++ b[11] = byte(d.length >> 8) b[12] = byte(d.length) d.length += 17 if d.length > 100 { d.length -= 50 } } // New creates a new UTP header for the given config. func New(ctx context.Context, config interface{}) (interface{}, error) { return &DTLS{ epoch: dice.RollUint16(), sequence: 0, length: 17, }, nil } func init() { common.Must(common.RegisterConfig((*PacketConfig)(nil), New)) }