// Copyright 2013 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 ipv4

import "golang.org/x/net/internal/iana"

// An ICMPType represents a type of ICMP message.
type ICMPType int

func (typ ICMPType) String() string {
	s, ok := icmpTypes[typ]
	if !ok {
		return "<nil>"
	}
	return s
}

// Protocol returns the ICMPv4 protocol number.
func (typ ICMPType) Protocol() int {
	return iana.ProtocolICMP
}

// An ICMPFilter represents an ICMP message filter for incoming
// packets. The filter belongs to a packet delivery path on a host and
// it cannot interact with forwarding packets or tunnel-outer packets.
//
// Note: RFC 2460 defines a reasonable role model and it works not
// only for IPv6 but IPv4. A node means a device that implements IP.
// A router means a node that forwards IP packets not explicitly
// addressed to itself, and a host means a node that is not a router.
type ICMPFilter struct {
	sysICMPFilter
}

// Accept accepts incoming ICMP packets including the type field value
// typ.
func (f *ICMPFilter) Accept(typ ICMPType) {
	f.accept(typ)
}

// Block blocks incoming ICMP packets including the type field value
// typ.
func (f *ICMPFilter) Block(typ ICMPType) {
	f.block(typ)
}

// SetAll sets the filter action to the filter.
func (f *ICMPFilter) SetAll(block bool) {
	f.setAll(block)
}

// WillBlock reports whether the ICMP type will be blocked.
func (f *ICMPFilter) WillBlock(typ ICMPType) bool {
	return f.willBlock(typ)
}