icmp_header Struct Reference
[Internet Control Message Protocol (ICMP) Service]

Internet control message header. More...

#include <icmp_header.h>

Collaboration diagram for icmp_header:

[legend]

Data Fields
uint8_t	type
	The type of the message.
uint8_t	code
	The error code for the datagram reported by the ICMP message.
uint16_t	checksum
	The checksum is the 16-bit ones's complement of the one's complement sum of the ICMP message starting with the ICMP Type.
union {
icmp_echo_t   echo
	Echo specific data.
in_addr_t   gateway
	Proposed gateway value.
struct {
icmp_param_t   reserved
	Reserved field.
icmp_param_t   mtu
	Proposed MTU.
}   frag
	Fragmentation needed specific data.
struct {
icmp_param_t   pointer
	Problem pointer.
icmp_param_t   reserved
	Reserved field.
}   param
	Parameter problem specific data.
}	un
	Message specific data.

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Detailed Description

Internet control message header.

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Field Documentation

uint16_t icmp_header::checksum

The checksum is the 16-bit ones's complement of the one's complement sum of the ICMP message starting with the ICMP Type.

For computing the checksum, the checksum field should be zero. If the checksum does not match the contents, the datagram is discarded.

Referenced by icmp_process_packet(), and icmp_send_packet().

uint8_t icmp_header::code

The error code for the datagram reported by the ICMP message.

The interpretation is dependent on the message type.

Referenced by icmp_client_process_packet(), and icmp_send_packet().

icmp_echo_t icmp_header::echo

Echo specific data.

Referenced by icmp_echo(), and icmp_process_echo_reply().

struct { ... } icmp_header::frag

Fragmentation needed specific data.

Referenced by icmp_client_process_packet().

in_addr_t icmp_header::gateway

Proposed gateway value.

icmp_param_t icmp_header::mtu

Proposed MTU.

struct { ... } icmp_header::param

Parameter problem specific data.

Referenced by icmp_client_process_packet().

icmp_param_t icmp_header::pointer

Problem pointer.

icmp_param_t icmp_header::reserved

Reserved field.

Must be zero.

uint8_t icmp_header::type

The type of the message.

Referenced by icmp_client_process_packet(), icmp_process_packet(), and icmp_send_packet().

union { ... } icmp_header::un

Message specific data.

Referenced by icmp_client_process_packet(), icmp_echo(), and icmp_process_echo_reply().

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The documentation for this struct was generated from the following file:

• tl/icmp/icmp_header.h