path: root/net/ipv4/arp.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* linux/net/ipv4/arp.c
 *
 * Copyright (C) 1994 by Florian  La Roche
 *
 * This module implements the Address Resolution Protocol ARP (RFC 826),
 * which is used to convert IP addresses (or in the future maybe other
 * high-level addresses) into a low-level hardware address (like an Ethernet
 * address).
 *
 * Fixes:
 *		Alan Cox	:	Removed the Ethernet assumptions in
 *					Florian's code
 *		Alan Cox	:	Fixed some small errors in the ARP
 *					logic
 *		Alan Cox	:	Allow >4K in /proc
 *		Alan Cox	:	Make ARP add its own protocol entry
 *		Ross Martin     :       Rewrote arp_rcv() and arp_get_info()
 *		Stephen Henson	:	Add AX25 support to arp_get_info()
 *		Alan Cox	:	Drop data when a device is downed.
 *		Alan Cox	:	Use init_timer().
 *		Alan Cox	:	Double lock fixes.
 *		Martin Seine	:	Move the arphdr structure
 *					to if_arp.h for compatibility.
 *					with BSD based programs.
 *		Andrew Tridgell :       Added ARP netmask code and
 *					re-arranged proxy handling.
 *		Alan Cox	:	Changed to use notifiers.
 *		Niibe Yutaka	:	Reply for this device or proxies only.
 *		Alan Cox	:	Don't proxy across hardware types!
 *		Jonathan Naylor :	Added support for NET/ROM.
 *		Mike Shaver     :       RFC1122 checks.
 *		Jonathan Naylor :	Only lookup the hardware address for
 *					the correct hardware type.
 *		Germano Caronni	:	Assorted subtle races.
 *		Craig Schlenter :	Don't modify permanent entry
 *					during arp_rcv.
 *		Russ Nelson	:	Tidied up a few bits.
 *		Alexey Kuznetsov:	Major changes to caching and behaviour,
 *					eg intelligent arp probing and