// ParseMessage parses b as an ICMP message. Proto must be
// iana.ProtocolICMP or iana.ProtocolIPv6ICMP.
func ParseMessage(proto int, b []byte) (*Message, error) {
if len(b) < 4 {
return nil, errors.New("message too short")
}
var err error
switch proto {
case iana.ProtocolICMP:
m := &Message{Type: ipv4.ICMPType(b[0]), Code: int(b[1]), Checksum: int(b[2])<<8 | int(b[3])}
switch m.Type {
case ipv4.ICMPTypeEcho, ipv4.ICMPTypeEchoReply:
m.Body, err = parseEcho(b[4:])
if err != nil {
return nil, err
}
default:
m.Body = &DefaultMessageBody{Data: b[4:]}
}
return m, nil
case iana.ProtocolIPv6ICMP:
m := &Message{Type: ipv6.ICMPType(b[0]), Code: int(b[1]), Checksum: int(b[2])<<8 | int(b[3])}
switch m.Type {
case ipv6.ICMPTypeEchoRequest, ipv6.ICMPTypeEchoReply:
m.Body, err = parseEcho(b[4:])
if err != nil {
return nil, err
}
default:
m.Body = &DefaultMessageBody{Data: b[4:]}
}
return m, nil
default:
return nil, errors.New("unknown protocol")
}
}
// ParseMessage parses b as an ICMP message.
// Proto must be either the ICMPv4 or ICMPv6 protocol number.
func ParseMessage(proto int, b []byte) (*Message, error) {
if len(b) < 4 {
return nil, errMessageTooShort
}
var err error
m := &Message{Code: int(b[1]), Checksum: int(b[2])<<8 | int(b[3])}
switch proto {
case iana.ProtocolICMP:
m.Type = ipv4.ICMPType(b[0])
case iana.ProtocolIPv6ICMP:
m.Type = ipv6.ICMPType(b[0])
default:
return nil, syscall.EINVAL
}
if fn, ok := parseFns[m.Type]; !ok {
m.Body, err = parseDefaultMessageBody(b[4:])
} else {
m.Body, err = fn(b[4:])
}
if err != nil {
return nil, err
}
return m, nil
}