mirror of
https://github.com/tailscale/tailscale.git
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79 lines
1.5 KiB
Go
79 lines
1.5 KiB
Go
// Copyright (c) 2020 Tailscale Inc & 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 packet
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type ICMPType uint8
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const (
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ICMPEchoReply ICMPType = 0x00
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ICMPEchoRequest ICMPType = 0x08
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ICMPUnreachable ICMPType = 0x03
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ICMPTimeExceeded ICMPType = 0x0b
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)
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func (t ICMPType) String() string {
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switch t {
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case ICMPEchoReply:
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return "EchoReply"
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case ICMPEchoRequest:
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return "EchoRequest"
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case ICMPUnreachable:
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return "Unreachable"
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case ICMPTimeExceeded:
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return "TimeExceeded"
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default:
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return "Unknown"
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}
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}
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type ICMPCode uint8
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const (
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ICMPNoCode ICMPCode = 0
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)
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// ICMPHeader represents an ICMP packet header.
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type ICMPHeader struct {
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IPHeader
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Type ICMPType
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Code ICMPCode
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}
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const (
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icmpHeaderLength = 4
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// icmpTotalHeaderLength is the length of all headers in a ICMP packet.
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icmpAllHeadersLength = ipHeaderLength + icmpHeaderLength
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)
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func (ICMPHeader) Len() int {
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return icmpAllHeadersLength
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}
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func (h ICMPHeader) Marshal(buf []byte) error {
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if len(buf) < icmpAllHeadersLength {
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return errSmallBuffer
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}
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if len(buf) > maxPacketLength {
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return errLargePacket
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}
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// The caller does not need to set this.
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h.IPProto = ICMP
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buf[20] = uint8(h.Type)
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buf[21] = uint8(h.Code)
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h.IPHeader.Marshal(buf)
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put16(buf[22:24], ipChecksum(buf))
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return nil
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}
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func (h *ICMPHeader) ToResponse() {
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h.Type = ICMPEchoReply
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h.Code = ICMPNoCode
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h.IPHeader.ToResponse()
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}
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