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// 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"
"golang.org/x/net/internal/iana"
"golang.org/x/net/ipv4"
)
// A ParamProb represents an ICMP parameter problem message body.
type ParamProb struct {
Pointer uintptr // offset within the data where the error was detected
Data []byte // data, known as original datagram field
Extensions []Extension // extensions
}
// Len implements the Len method of MessageBody interface.
func (p *ParamProb) Len(proto int) int {
if p == nil {
return 0
}
l, _ := multipartMessageBodyDataLen(proto, true, p.Data, p.Extensions)
return l
}
// Marshal implements the Marshal method of MessageBody interface.
func (p *ParamProb) Marshal(proto int) ([]byte, error) {
switch proto {
case iana.ProtocolICMP:
if !validExtensions(ipv4.ICMPTypeParameterProblem, p.Extensions) {
return nil, errInvalidExtension
}
b, err := marshalMultipartMessageBody(proto, true, p.Data, p.Extensions)
if err != nil {
return nil, err
}
b[0] = byte(p.Pointer)
return b, nil
case iana.ProtocolIPv6ICMP:
b := make([]byte, p.Len(proto))
binary.BigEndian.PutUint32(b[:4], uint32(p.Pointer))
copy(b[4:], p.Data)
return b, nil
default:
return nil, errInvalidProtocol
}
}
// parseParamProb parses b as an ICMP parameter problem message body.
func parseParamProb(proto int, typ Type, b []byte) (MessageBody, error) {
if len(b) < 4 {
return nil, errMessageTooShort
}
p := &ParamProb{}
if proto == iana.ProtocolIPv6ICMP {
p.Pointer = uintptr(binary.BigEndian.Uint32(b[:4]))
p.Data = make([]byte, len(b)-4)
copy(p.Data, b[4:])
return p, nil
}
p.Pointer = uintptr(b[0])
var err error
p.Data, p.Extensions, err = parseMultipartMessageBody(proto, typ, b)
if err != nil {
return nil, err
}
return p, nil
}