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v2ray-core/transport/internet/headers/tls/dtls.go

57 lines
1.1 KiB

package tls
import (
"context"
"v2ray.com/core/common"
"v2ray.com/core/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
}
// Write implements PacketHeader.
func (d *DTLS) Write(b []byte) (int, error) {
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
}
return 13, nil
}
// 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))
}