1// Copyright 2013 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package ipv4
6
7import "golang.org/x/net/internal/iana"
8
9// An ICMPType represents a type of ICMP message.
10type ICMPType int
11
12func (typ ICMPType) String() string {
13	s, ok := icmpTypes[typ]
14	if !ok {
15		return "<nil>"
16	}
17	return s
18}
19
20// Protocol returns the ICMPv4 protocol number.
21func (typ ICMPType) Protocol() int {
22	return iana.ProtocolICMP
23}
24
25// An ICMPFilter represents an ICMP message filter for incoming
26// packets. The filter belongs to a packet delivery path on a host and
27// it cannot interact with forwarding packets or tunnel-outer packets.
28//
29// Note: RFC 8200 defines a reasonable role model and it works not
30// only for IPv6 but IPv4. A node means a device that implements IP.
31// A router means a node that forwards IP packets not explicitly
32// addressed to itself, and a host means a node that is not a router.
33type ICMPFilter struct {
34	icmpFilter
35}
36
37// Accept accepts incoming ICMP packets including the type field value
38// typ.
39func (f *ICMPFilter) Accept(typ ICMPType) {
40	f.accept(typ)
41}
42
43// Block blocks incoming ICMP packets including the type field value
44// typ.
45func (f *ICMPFilter) Block(typ ICMPType) {
46	f.block(typ)
47}
48
49// SetAll sets the filter action to the filter.
50func (f *ICMPFilter) SetAll(block bool) {
51	f.setAll(block)
52}
53
54// WillBlock reports whether the ICMP type will be blocked.
55func (f *ICMPFilter) WillBlock(typ ICMPType) bool {
56	return f.willBlock(typ)
57}
58