---
name: "NetPacket::ICMP"
section: "3pm"
platform: "linux"
package: "libnetpacket-perl"
version: "1.7.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/NetPacket::ICMP"
---

# NetPacket::ICMP(3pm)

Assemble and disassemble ICMP (Internet Control Message Protocol) packets.

## NAME

NetPacket::ICMP - Assemble and disassemble ICMP (Internet Control Message Protocol) packets.

## VERSION

version 1.7.2

## SYNOPSIS

```
  use NetPacket::ICMP;
  $icmp_obj = NetPacket::ICMP->decode($raw_pkt);
  $icmp_pkt = NetPacket::ICMP->encode();
  $icmp_data = NetPacket::ICMP::strip($raw_pkt);
```

## DESCRIPTION

`"NetPacket::ICMP"` provides a set of routines for assembling and disassembling packets using ICMP (Internet Control Message Protocol).

### Methods

- "NetPacket::ICMP-\>decode(\[RAW PACKET\])"

  Decode the raw packet data given and return an object containing instance data.  This method will quite happily decode garbage input. It is the responsibility of the programmer to ensure valid packet data is passed to this method.

- "NetPacket::ICMP-\>encode()"

  Return an ICMP packet encoded with the instance data specified.

### Functions

- "NetPacket::ICMP::strip(\[RAW PACKET\])"

  Return the encapsulated data (or payload) contained in the ICMP packet.

### Instance data

The instance data for the `"NetPacket::ICMP"` object consists of the following fields.

- type

  The ICMP message type of this packet.

- code

  The ICMP message code of this packet.

- cksum

  The checksum for this packet.

- data

  The encapsulated data (payload) for this packet.

### Exports

- default

  none

- exportable

  ICMP message types:\
       ICMP\_ECHOREPLY ICMP\_UNREACH ICMP\_SOURCEQUENCH\
       ICMP\_REDIRECT ICMP\_ECHO ICMP\_ROUTERADVERT\
       ICMP\_ROUTERSOLICIT ICMP\_TIMXCEED ICMP\_PARAMPROB\
       ICMP\_TSTAMP ICMP\_TSTAMPREPLY ICMP\_IREQ ICMP\_IREQREPLY\
       ICMP\_MASKREQ ICMP\_MASKREPLY

- tags

  The following tags group together related exportable items.

  - ":types"

    ```
      ICMP_ECHOREPLY ICMP_UNREACH ICMP_SOURCEQUENCH
      ICMP_REDIRECT ICMP_ECHO ICMP_ROUTERADVERT
      ICMP_ROUTERSOLICIT ICMP_TIMXCEED ICMP_PARAMPROB
      ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_IREQ
      ICMP_IREQREPLY ICMP_MASKREQ ICMP_MASKREPLY
    ```

  - ":strip"

    Import the strip function `"icmp_strip"`.

  - ":ALL"

    All the above exportable items.

## EXAMPLE

The following example prints the ICMP type, code, and checksum fields.

```
  #!/usr/bin/perl -w
  use strict;
  use Net::PcapUtils;
  use NetPacket::Ethernet qw(:strip);
  use NetPacket::IP qw(:strip);
  use NetPacket::ICMP;
  sub process_pkt {
      my ($user, $hdr, $pkt) = @_;
      my $ip_obj = NetPacket::IP->decode(eth_strip($pkt));
      my $icmp_obj = NetPacket::ICMP->decode(ip_strip($ip_obj));
      print("Type: $icmp_obj->{type}\n");
      print("Code: $icmp_obj->{code}\n");
      print("Checksum: $icmp_obj->{cksum}\n\n");
  }
  Net::PcapUtils::loop(\&process_pkt, FILTER => 'icmp');
```

## TODO

- Create constants

  ## COPYRIGHT

Copyright (c) 2001 Tim Potter and Stephanie Wehner.

Copyright (c) 1995,1996,1997,1998,1999 ANU and CSIRO on behalf of the participants in the CRC for Advanced Computational Systems ('ACSys').

This module is free software.  You can redistribute it and/or modify it under the terms of the Artistic License 2.0.

This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose.

## AUTHOR

Tim Potter \<tpot@samba.org\>

Stephanie Wehner \<atrak@itsx.com\>