forked from pion/dtls
/
handshake_random.go
47 lines (36 loc) · 1.02 KB
/
handshake_random.go
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package dtls
import (
"crypto/rand"
"encoding/binary"
"time"
)
const randomBytesLength = 28
const handshakeRandomLength = randomBytesLength + 4
// https://tools.ietf.org/html/rfc4346#section-7.4.1.2
type handshakeRandom struct {
gmtUnixTime time.Time
randomBytes [randomBytesLength]byte
}
func (h *handshakeRandom) Marshal() ([]byte, error) {
out := make([]byte, handshakeRandomLength)
binary.BigEndian.PutUint32(out[0:], uint32(h.gmtUnixTime.Unix()))
copy(out[4:], h.randomBytes[:])
return out, nil
}
func (h *handshakeRandom) Unmarshal(data []byte) error {
if len(data) != handshakeRandomLength {
return errBufferTooSmall
}
h.gmtUnixTime = time.Unix(int64(binary.BigEndian.Uint32(data[0:])), 0)
copy(h.randomBytes[:], data[4:])
return nil
}
// populate fills the handshakeRandom with random values
// may be called multiple times
func (h *handshakeRandom) populate() error {
h.gmtUnixTime = time.Now()
tmp := make([]byte, randomBytesLength)
_, err := rand.Read(tmp)
copy(h.randomBytes[:], tmp)
return err
}