157 lines
3.9 KiB
Go
157 lines
3.9 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package icmp
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import "encoding/binary"
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// An Echo represents an ICMP echo request or reply message body.
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type Echo struct {
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ID int // identifier
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Seq int // sequence number
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Data []byte // data
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}
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// Len implements the Len method of MessageBody interface.
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func (p *Echo) Len(proto int) int {
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if p == nil {
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return 0
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}
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return 4 + len(p.Data)
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}
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// Marshal implements the Marshal method of MessageBody interface.
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func (p *Echo) Marshal(proto int) ([]byte, error) {
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b := make([]byte, 4+len(p.Data))
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binary.BigEndian.PutUint16(b[:2], uint16(p.ID))
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binary.BigEndian.PutUint16(b[2:4], uint16(p.Seq))
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copy(b[4:], p.Data)
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return b, nil
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}
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// parseEcho parses b as an ICMP echo request or reply message body.
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func parseEcho(proto int, _ Type, b []byte) (MessageBody, error) {
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bodyLen := len(b)
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if bodyLen < 4 {
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return nil, errMessageTooShort
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}
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p := &Echo{ID: int(binary.BigEndian.Uint16(b[:2])), Seq: int(binary.BigEndian.Uint16(b[2:4]))}
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if bodyLen > 4 {
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p.Data = make([]byte, bodyLen-4)
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copy(p.Data, b[4:])
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}
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return p, nil
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}
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// An ExtendedEchoRequest represents an ICMP extended echo request
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// message body.
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type ExtendedEchoRequest struct {
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ID int // identifier
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Seq int // sequence number
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Local bool // must be true when identifying by name or index
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Extensions []Extension // extensions
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}
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// Len implements the Len method of MessageBody interface.
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func (p *ExtendedEchoRequest) Len(proto int) int {
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if p == nil {
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return 0
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}
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l, _ := multipartMessageBodyDataLen(proto, false, nil, p.Extensions)
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return 4 + l
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}
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// Marshal implements the Marshal method of MessageBody interface.
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func (p *ExtendedEchoRequest) Marshal(proto int) ([]byte, error) {
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b, err := marshalMultipartMessageBody(proto, false, nil, p.Extensions)
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if err != nil {
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return nil, err
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}
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bb := make([]byte, 4)
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binary.BigEndian.PutUint16(bb[:2], uint16(p.ID))
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bb[2] = byte(p.Seq)
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if p.Local {
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bb[3] |= 0x01
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}
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bb = append(bb, b...)
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return bb, nil
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}
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// parseExtendedEchoRequest parses b as an ICMP extended echo request
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// message body.
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func parseExtendedEchoRequest(proto int, typ Type, b []byte) (MessageBody, error) {
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if len(b) < 4+4 {
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return nil, errMessageTooShort
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}
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p := &ExtendedEchoRequest{ID: int(binary.BigEndian.Uint16(b[:2])), Seq: int(b[2])}
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if b[3]&0x01 != 0 {
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p.Local = true
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}
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var err error
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_, p.Extensions, err = parseMultipartMessageBody(proto, typ, b[4:])
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if err != nil {
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return nil, err
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}
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return p, nil
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}
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// An ExtendedEchoReply represents an ICMP extended echo reply message
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// body.
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type ExtendedEchoReply struct {
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ID int // identifier
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Seq int // sequence number
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State int // 3-bit state working together with Message.Code
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Active bool // probed interface is active
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IPv4 bool // probed interface runs IPv4
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IPv6 bool // probed interface runs IPv6
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}
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// Len implements the Len method of MessageBody interface.
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func (p *ExtendedEchoReply) Len(proto int) int {
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if p == nil {
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return 0
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}
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return 4
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}
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// Marshal implements the Marshal method of MessageBody interface.
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func (p *ExtendedEchoReply) Marshal(proto int) ([]byte, error) {
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b := make([]byte, 4)
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binary.BigEndian.PutUint16(b[:2], uint16(p.ID))
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b[2] = byte(p.Seq)
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b[3] = byte(p.State<<5) & 0xe0
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if p.Active {
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b[3] |= 0x04
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}
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if p.IPv4 {
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b[3] |= 0x02
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}
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if p.IPv6 {
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b[3] |= 0x01
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}
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return b, nil
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}
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// parseExtendedEchoReply parses b as an ICMP extended echo reply
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// message body.
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func parseExtendedEchoReply(proto int, _ Type, b []byte) (MessageBody, error) {
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if len(b) < 4 {
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return nil, errMessageTooShort
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}
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p := &ExtendedEchoReply{
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ID: int(binary.BigEndian.Uint16(b[:2])),
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Seq: int(b[2]),
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State: int(b[3]) >> 5,
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}
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if b[3]&0x04 != 0 {
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p.Active = true
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}
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if b[3]&0x02 != 0 {
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p.IPv4 = true
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}
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if b[3]&0x01 != 0 {
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p.IPv6 = true
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}
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return p, nil
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}
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