icmp.lua File Reference

Internet control message protocol utility. More...

Go to the source code of this file.

Functions
function icmpHeader	setType (int)
	Set the type. More...
function icmpHeader	getType ()
	Retrieve the type. More...
function icmpHeader	getTypeString ()
	Retrieve the type. More...
function icmpHeader	setCode (int)
	Set the code. More...
function icmpHeader	getCode ()
	Retrieve the code. More...
function icmpHeader	getCodeString ()
	Retrieve the code. More...
function icmpHeader	setChecksum (int)
	Set the checksum. More...
function icmpHeader	calculateChecksum (len)
	Calculate the checksum. More...
function icmpHeader	getChecksum ()
	Retrieve the checksum. More...
function icmpHeader	getChecksumString ()
	Retrieve the checksum. More...
function icmpHeader	setMessageBody (body)
	Set the message body. More...
function icmpHeader	getMessageBody ()
	Retrieve the message body. More...
function icmpHeader	getMessageBodyString ()
	Retrieve the message body. More...
function icmpHeader	fill (args, pre)
	Set all members of the icmp header. More...
function icmpHeader	get (pre)
	Retrieve the values of all members. More...
function icmpHeader	getString ()
	Retrieve the values of all members. More...
function icmpHeader	resolveNextHeader ()
	Resolve which header comes after this one (in a packet). More...
function icmpHeader	setDefaultNamedArgs (pre, namedArgs, nextHeader, accumulatedLength)
	Change the default values for namedArguments (for fill/get). More...

Variables
local	icmp = {}
	Icmp4 protocol constants.
icmp	ECHO_REPLY = { type = 0, code = 0 }
	Icmp4 type-code pair: echo reply. More...
icmp	ECHO_REQUEST = { type = 8, code = 0 }
	Icmp4 type-code pair: echo request. More...
icmp	DST_UNR_PORT_UNR = { type = 3, code = 3 }
	Icmp4 type-code pair: destination unreachable - port unreachable.
icmp	TIME_EXCEEDED_TTL_EXPIRED = { type = 11, code = 0 }
	Icmp4 type-code pair: time exceeded - TTL exceeded.
local	icmp6 = {}
	Icmp6 protocol constants.
local	icmpHeader = {}
	Module for icmp_header struct (see headers.lua).
pkt	getIcmp4Packet = packetCreate("eth", "ip4", "icmp")
	Cast the packet to an Icmp4 packet.
pkt	getIcmp6Packet = packetCreate("eth", "ip6", "icmp")
	Cast the packet to an Icmp6 packet.

Detailed Description

Internet control message protocol utility.

Utility functions for the icmp_header struct defined in headers.lua .
Includes:

• Icmp4 constants
• Icmp6 constants
• Icmp header utility
• Definition of Icmp packets

Definition in file icmp.lua.

Function Documentation

function icmpHeader calculateChecksum

(

len

)

Calculate the checksum.

Parameters

len	Number of bytes that the checksum will be computed over

function icmpHeader fill	(	args	,
		pre
	)

Set all members of the icmp header.

Per default, all members are set to default values specified in the respective set function. Optional named arguments can be used to set a member to a user-provided value.

Parameters

args	Table of named arguments. Available arguments: Type, Code, Checksum, MessageBody
pre	prefix for namedArgs. Default 'icmp'. fill() --- only default values fill{ icmpCode=3 } --- all members are set to default values with the exception of icmpCode

function icmpHeader get

(

pre

)

Retrieve the values of all members.

Parameters

pre	prefix for namedArgs. Default 'icmp'.

Returns

Table of named arguments. For a list of arguments see "See also".

See Also

icmpHeader:fill

function icmpHeader getChecksum

(

)

Retrieve the checksum.

Returns

Checksum as 16 bit integer.

function icmpHeader getChecksumString

(

)

Retrieve the checksum.

Returns

Checksum as string.

function icmpHeader getCode

(

)

Retrieve the code.

Returns

Code as 8 bit integer.

function icmpHeader getCodeString

(

)

Retrieve the code.

does not work for ICMPv6

Returns

Code as string.

function icmpHeader getMessageBody

(

)

Retrieve the message body.

Returns

Message body as TODO.

function icmpHeader getMessageBodyString

(

)

Retrieve the message body.

Returns

Message body as string TODO.

function icmpHeader getString

(

)

Retrieve the values of all members.

Does not work correctly for ICMPv6 packets

Returns

Values in string format.

function icmpHeader getType

(

)

Retrieve the type.

Returns

Type as 8 bit integer.

function icmpHeader getTypeString

(

)

Retrieve the type.

does not work for ICMPv6 (ICMPv6 uses different values)

Returns

Type as string.

function icmpHeader resolveNextHeader

(

)

Resolve which header comes after this one (in a packet).

For instance: in tcp/udp based on the ports. This function must exist and is only used when get/dump is executed on an unknown (mbuf not yet casted to e.g. tcpv6 packet) packet (mbuf)

Returns

String next header (e.g. 'udp', 'icmp', nil)

function icmpHeader setChecksum

(

int

)

Set the checksum.

Parameters

int	Checksum of the icmp header as 16 bit integer.

function icmpHeader setCode

(

int

)

Set the code.

Parameters

int	Code of the icmp header as 8 bit integer.

function icmpHeader setDefaultNamedArgs	(	pre	,
		namedArgs	,
		nextHeader	,
		accumulatedLength
	)

Change the default values for namedArguments (for fill/get).

This can be used to for instance calculate a length value based on the total packet length. See proto/ip4.setDefaultNamedArgs as an example. This function must exist and is only used by packet.fill.

Parameters

pre	The prefix used for the namedArgs, e.g. 'icmp'
namedArgs	Table of named arguments (see See Also)
nextHeader	The header following after this header in a packet
accumulatedLength	The so far accumulated length for previous headers in a packet

Returns

Table of namedArgs

See Also

icmpHeader:fill

function icmpHeader setMessageBody

(

body

)

Set the message body.

Parameters

int	Message body of the icmp header as TODO.

function icmpHeader setType

(

int

)

Set the type.

Parameters

int	Type of the icmp header as 8 bit integer.

Variable Documentation

icmp6 ECHO_REPLY = { type = 0, code = 0 }

Icmp4 type-code pair: echo reply.

Icmp6 type-code pair: echo reply.

Definition at line 28 of file icmp.lua.

icmp6 ECHO_REQUEST = { type = 8, code = 0 }

Icmp4 type-code pair: echo request.

Icmp6 type-code pair: echo request.

Definition at line 30 of file icmp.lua.