arp.h File Reference

#include <net/net.h>
#include <stdint.h>

Include dependency graph for arp.h:

Data Structures
struct	arp_packet_t

Functions
void	arp_request (net_interface_t *interface, uint8_t ip[4])
void	arp_wait_reply (uint8_t *dst_mac)
void	arp_receive_packet (net_interface_t *interface, uint8_t *data, uint32_t len)

Detailed Description

See also

https://tools.ietf.org/html/rfc826

https://www.saminiir.com/lets-code-tcp-ip-stack-1-ethernet-arp/

The Address Resolution Protocol (ARP) is used for dynamically mapping a local MAC address (Ethernet) to a protocol address (IPv4) by broadcasting a packet to all the machines on the LAN. If one of the machines uses this address, it should send a ARP reply.

This module allows to send a ARP request on a given interface. The current "wait for a response" implementation is not bound to an interface, though, and it is implemented as a busyloop. There is no ARP cache either. Apart from that, it works great!

Function Documentation

arp_receive_packet()

void arp_receive_packet	(	net_interface_t *	interface,
		uint8_t *	data,
		uint32_t	len )

Handles ARP packets that are received on an interface.

Parameters

interface	the interface that received the ARP packet
data	the data containing the ARP packet
len	the length of the data

arp_request()

void arp_request	(	net_interface_t *	interface,
		uint8_t	ip[4] )

ARP request.

Parameters

interface	the interface to use to send the ARP request
ip	an IPv4 address

arp_wait_reply()

void arp_wait_reply

(

uint8_t *

dst_mac

)

Wait a bit to hopefully get a ARP reply. If a ARP reply is received, the buffer will be updated with the MAC address. Otherwise, the buffer will contain 0 values only.

Parameters

dst_mac

a pointer to a buffer large enough to receive a MAC address