yggdrasil-go/src/multicast/advertisement.go
2023-10-11 19:28:28 +01:00

40 lines
1.2 KiB
Go

package multicast
import (
"crypto/ed25519"
"encoding/binary"
"fmt"
)
type multicastAdvertisement struct {
MajorVersion uint16
MinorVersion uint16
PublicKey ed25519.PublicKey
Port uint16
Hash []byte
}
func (m *multicastAdvertisement) MarshalBinary() ([]byte, error) {
b := make([]byte, 0, ed25519.PublicKeySize+8+len(m.Hash))
b = binary.BigEndian.AppendUint16(b, m.MajorVersion)
b = binary.BigEndian.AppendUint16(b, m.MinorVersion)
b = append(b, m.PublicKey...)
b = binary.BigEndian.AppendUint16(b, m.Port)
b = binary.BigEndian.AppendUint16(b, uint16(len(m.Hash)))
b = append(b, m.Hash...)
return b, nil
}
func (m *multicastAdvertisement) UnmarshalBinary(b []byte) error {
if len(b) < ed25519.PublicKeySize+8 {
return fmt.Errorf("invalid multicast beacon")
}
m.MajorVersion = binary.BigEndian.Uint16(b[0:2])
m.MinorVersion = binary.BigEndian.Uint16(b[2:4])
m.PublicKey = append(m.PublicKey[:0], b[4:4+ed25519.PublicKeySize]...)
m.Port = binary.BigEndian.Uint16(b[4+ed25519.PublicKeySize : 6+ed25519.PublicKeySize])
dl := binary.BigEndian.Uint16(b[6+ed25519.PublicKeySize : 8+ed25519.PublicKeySize])
m.Hash = append(m.Hash[:0], b[8+ed25519.PublicKeySize:8+ed25519.PublicKeySize+dl]...)
return nil
}