43 lines
1.2 KiB
Go
43 lines
1.2 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package icmp
|
|
|
|
import "encoding/binary"
|
|
|
|
// A PacketTooBig represents an ICMP packet too big message body.
|
|
type PacketTooBig struct {
|
|
MTU int // maximum transmission unit of the nexthop link
|
|
Data []byte // data, known as original datagram field
|
|
}
|
|
|
|
// Len implements the Len method of MessageBody interface.
|
|
func (p *PacketTooBig) Len(proto int) int {
|
|
if p == nil {
|
|
return 0
|
|
}
|
|
return 4 + len(p.Data)
|
|
}
|
|
|
|
// Marshal implements the Marshal method of MessageBody interface.
|
|
func (p *PacketTooBig) Marshal(proto int) ([]byte, error) {
|
|
b := make([]byte, 4+len(p.Data))
|
|
binary.BigEndian.PutUint32(b[:4], uint32(p.MTU))
|
|
copy(b[4:], p.Data)
|
|
return b, nil
|
|
}
|
|
|
|
// parsePacketTooBig parses b as an ICMP packet too big message body.
|
|
func parsePacketTooBig(proto int, _ Type, b []byte) (MessageBody, error) {
|
|
bodyLen := len(b)
|
|
if bodyLen < 4 {
|
|
return nil, errMessageTooShort
|
|
}
|
|
p := &PacketTooBig{MTU: int(binary.BigEndian.Uint32(b[:4]))}
|
|
if bodyLen > 4 {
|
|
p.Data = make([]byte, bodyLen-4)
|
|
copy(p.Data, b[4:])
|
|
}
|
|
return p, nil
|
|
}
|