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// Copyright 2016 The Netstack 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 header
import (
"encoding/binary"
"gvisor.googlesource.com/gvisor/pkg/tcpip"
)
// ICMPv4 represents an ICMPv4 header stored in a byte array.
type ICMPv4 []byte
const (
// ICMPv4MinimumSize is the minimum size of a valid ICMP packet.
ICMPv4MinimumSize = 4
// ICMPv4EchoMinimumSize is the minimum size of a valid ICMP echo packet.
ICMPv4EchoMinimumSize = 6
// ICMPv4DstUnreachableMinimumSize is the minimum size of a valid ICMP
// destination unreachable packet.
ICMPv4DstUnreachableMinimumSize = ICMPv4MinimumSize + 4
// ICMPv4ProtocolNumber is the ICMP transport protocol number.
ICMPv4ProtocolNumber tcpip.TransportProtocolNumber = 1
)
// ICMPv4Type is the ICMP type field described in RFC 792.
type ICMPv4Type byte
// Typical values of ICMPv4Type defined in RFC 792.
const (
ICMPv4EchoReply ICMPv4Type = 0
ICMPv4DstUnreachable ICMPv4Type = 3
ICMPv4SrcQuench ICMPv4Type = 4
ICMPv4Redirect ICMPv4Type = 5
ICMPv4Echo ICMPv4Type = 8
ICMPv4TimeExceeded ICMPv4Type = 11
ICMPv4ParamProblem ICMPv4Type = 12
ICMPv4Timestamp ICMPv4Type = 13
ICMPv4TimestampReply ICMPv4Type = 14
ICMPv4InfoRequest ICMPv4Type = 15
ICMPv4InfoReply ICMPv4Type = 16
)
// Values for ICMP code as defined in RFC 792.
const (
ICMPv4PortUnreachable = 3
ICMPv4FragmentationNeeded = 4
)
// Type is the ICMP type field.
func (b ICMPv4) Type() ICMPv4Type { return ICMPv4Type(b[0]) }
// SetType sets the ICMP type field.
func (b ICMPv4) SetType(t ICMPv4Type) { b[0] = byte(t) }
// Code is the ICMP code field. Its meaning depends on the value of Type.
func (b ICMPv4) Code() byte { return b[1] }
// SetCode sets the ICMP code field.
func (b ICMPv4) SetCode(c byte) { b[1] = c }
// Checksum is the ICMP checksum field.
func (b ICMPv4) Checksum() uint16 {
return binary.BigEndian.Uint16(b[2:])
}
// SetChecksum sets the ICMP checksum field.
func (b ICMPv4) SetChecksum(checksum uint16) {
binary.BigEndian.PutUint16(b[2:], checksum)
}
// SourcePort implements Transport.SourcePort.
func (ICMPv4) SourcePort() uint16 {
return 0
}
// DestinationPort implements Transport.DestinationPort.
func (ICMPv4) DestinationPort() uint16 {
return 0
}
// SetSourcePort implements Transport.SetSourcePort.
func (ICMPv4) SetSourcePort(uint16) {
}
// SetDestinationPort implements Transport.SetDestinationPort.
func (ICMPv4) SetDestinationPort(uint16) {
}
// Payload implements Transport.Payload.
func (b ICMPv4) Payload() []byte {
return b[ICMPv4MinimumSize:]
}
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