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// Copyright 2012 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"
"golang.org/x/net/ipv6"
)
// An Echo represents an ICMP echo request or reply message body.
type Echo struct {
ID int // identifier
Seq int // sequence number
Data []byte // data
}
// Len implements the Len method of MessageBody interface.
func (p *Echo) Len(proto int) int {
if p == nil {
return 0
}
return 4 + len(p.Data)
}
// Marshal implements the Marshal method of MessageBody interface.
func (p *Echo) Marshal(proto int) ([]byte, error) {
b := make([]byte, 4+len(p.Data))
binary.BigEndian.PutUint16(b[:2], uint16(p.ID))
binary.BigEndian.PutUint16(b[2:4], uint16(p.Seq))
copy(b[4:], p.Data)
return b, nil
}
// parseEcho parses b as an ICMP echo request or reply message body.
func parseEcho(proto int, _ Type, b []byte) (MessageBody, error) {
bodyLen := len(b)
if bodyLen < 4 {
return nil, errMessageTooShort
}
p := &Echo{ID: int(binary.BigEndian.Uint16(b[:2])), Seq: int(binary.BigEndian.Uint16(b[2:4]))}
if bodyLen > 4 {
p.Data = make([]byte, bodyLen-4)
copy(p.Data, b[4:])
}
return p, nil
}
// An ExtendedEchoRequest represents an ICMP extended echo request
// message body.
type ExtendedEchoRequest struct {
ID int // identifier
Seq int // sequence number
Local bool // must be true when identifying by name or index
Extensions []Extension // extensions
}
// Len implements the Len method of MessageBody interface.
func (p *ExtendedEchoRequest) Len(proto int) int {
if p == nil {
return 0
}
l, _ := multipartMessageBodyDataLen(proto, false, nil, p.Extensions)
return l
}
// Marshal implements the Marshal method of MessageBody interface.
func (p *ExtendedEchoRequest) Marshal(proto int) ([]byte, error) {
var typ Type
switch proto {
case iana.ProtocolICMP:
typ = ipv4.ICMPTypeExtendedEchoRequest
case iana.ProtocolIPv6ICMP:
typ = ipv6.ICMPTypeExtendedEchoRequest
default:
return nil, errInvalidProtocol
}
if !validExtensions(typ, p.Extensions) {
return nil, errInvalidExtension
}
b, err := marshalMultipartMessageBody(proto, false, nil, p.Extensions)
if err != nil {
return nil, err
}
binary.BigEndian.PutUint16(b[:2], uint16(p.ID))
b[2] = byte(p.Seq)
if p.Local {
b[3] |= 0x01
}
return b, nil
}
// parseExtendedEchoRequest parses b as an ICMP extended echo request
// message body.
func parseExtendedEchoRequest(proto int, typ Type, b []byte) (MessageBody, error) {
if len(b) < 4 {
return nil, errMessageTooShort
}
p := &ExtendedEchoRequest{ID: int(binary.BigEndian.Uint16(b[:2])), Seq: int(b[2])}
if b[3]&0x01 != 0 {
p.Local = true
}
var err error
_, p.Extensions, err = parseMultipartMessageBody(proto, typ, b)
if err != nil {
return nil, err
}
return p, nil
}
// An ExtendedEchoReply represents an ICMP extended echo reply message
// body.
type ExtendedEchoReply struct {
ID int // identifier
Seq int // sequence number
State int // 3-bit state working together with Message.Code
Active bool // probed interface is active
IPv4 bool // probed interface runs IPv4
IPv6 bool // probed interface runs IPv6
}
// Len implements the Len method of MessageBody interface.
func (p *ExtendedEchoReply) Len(proto int) int {
if p == nil {
return 0
}
return 4
}
// Marshal implements the Marshal method of MessageBody interface.
func (p *ExtendedEchoReply) Marshal(proto int) ([]byte, error) {
b := make([]byte, 4)
binary.BigEndian.PutUint16(b[:2], uint16(p.ID))
b[2] = byte(p.Seq)
b[3] = byte(p.State<<5) & 0xe0
if p.Active {
b[3] |= 0x04
}
if p.IPv4 {
b[3] |= 0x02
}
if p.IPv6 {
b[3] |= 0x01
}
return b, nil
}
// parseExtendedEchoReply parses b as an ICMP extended echo reply
// message body.
func parseExtendedEchoReply(proto int, _ Type, b []byte) (MessageBody, error) {
if len(b) < 4 {
return nil, errMessageTooShort
}
p := &ExtendedEchoReply{
ID: int(binary.BigEndian.Uint16(b[:2])),
Seq: int(b[2]),
State: int(b[3]) >> 5,
}
if b[3]&0x04 != 0 {
p.Active = true
}
if b[3]&0x02 != 0 {
p.IPv4 = true
}
if b[3]&0x01 != 0 {
p.IPv6 = true
}
return p, nil
}
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