arp.c 34.5 KB
Newer Older
1
/* linux/net/ipv4/arp.c
L
Linus Torvalds 已提交
2 3 4 5 6 7 8 9 10 11 12 13 14 15
 *
 * 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).
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * Fixes:
16
 *		Alan Cox	:	Removed the Ethernet assumptions in
L
Linus Torvalds 已提交
17
 *					Florian's code
18
 *		Alan Cox	:	Fixed some small errors in the ARP
L
Linus Torvalds 已提交
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
 *					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.
40
 *		Craig Schlenter :	Don't modify permanent entry
L
Linus Torvalds 已提交
41 42 43
 *					during arp_rcv.
 *		Russ Nelson	:	Tidied up a few bits.
 *		Alexey Kuznetsov:	Major changes to caching and behaviour,
44
 *					eg intelligent arp probing and
L
Linus Torvalds 已提交
45 46 47 48 49 50
 *					generation
 *					of host down events.
 *		Alan Cox	:	Missing unlock in device events.
 *		Eckes		:	ARP ioctl control errors.
 *		Alexey Kuznetsov:	Arp free fix.
 *		Manuel Rodriguez:	Gratuitous ARP.
51
 *              Jonathan Layes  :       Added arpd support through kerneld
L
Linus Torvalds 已提交
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78
 *                                      message queue (960314)
 *		Mike Shaver	:	/proc/sys/net/ipv4/arp_* support
 *		Mike McLagan    :	Routing by source
 *		Stuart Cheshire	:	Metricom and grat arp fixes
 *					*** FOR 2.1 clean this up ***
 *		Lawrence V. Stefani: (08/12/96) Added FDDI support.
 *		Alan Cox 	:	Took the AP1000 nasty FDDI hack and
 *					folded into the mainstream FDDI code.
 *					Ack spit, Linus how did you allow that
 *					one in...
 *		Jes Sorensen	:	Make FDDI work again in 2.1.x and
 *					clean up the APFDDI & gen. FDDI bits.
 *		Alexey Kuznetsov:	new arp state machine;
 *					now it is in net/core/neighbour.c.
 *		Krzysztof Halasa:	Added Frame Relay ARP support.
 *		Arnaldo C. Melo :	convert /proc/net/arp to seq_file
 *		Shmulik Hen:		Split arp_send to arp_create and
 *					arp_xmit so intermediate drivers like
 *					bonding can change the skb before
 *					sending (e.g. insert 8021q tag).
 *		Harald Welte	:	convert to make use of jenkins hash
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
79
#include <linux/capability.h>
L
Linus Torvalds 已提交
80 81 82 83 84 85
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/inet.h>
86
#include <linux/inetdevice.h>
L
Linus Torvalds 已提交
87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/fddidevice.h>
#include <linux/if_arp.h>
#include <linux/trdevice.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/net.h>
#include <linux/rcupdate.h>
#include <linux/jhash.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif

104
#include <net/net_namespace.h>
L
Linus Torvalds 已提交
105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199
#include <net/ip.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/arp.h>
#include <net/ax25.h>
#include <net/netrom.h>
#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
#include <net/atmclip.h>
struct neigh_table *clip_tbl_hook;
#endif

#include <asm/system.h>
#include <asm/uaccess.h>

#include <linux/netfilter_arp.h>

/*
 *	Interface to generic neighbour cache.
 */
static u32 arp_hash(const void *pkey, const struct net_device *dev);
static int arp_constructor(struct neighbour *neigh);
static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
static void parp_redo(struct sk_buff *skb);

static struct neigh_ops arp_generic_ops = {
	.family =		AF_INET,
	.solicit =		arp_solicit,
	.error_report =		arp_error_report,
	.output =		neigh_resolve_output,
	.connected_output =	neigh_connected_output,
	.hh_output =		dev_queue_xmit,
	.queue_xmit =		dev_queue_xmit,
};

static struct neigh_ops arp_hh_ops = {
	.family =		AF_INET,
	.solicit =		arp_solicit,
	.error_report =		arp_error_report,
	.output =		neigh_resolve_output,
	.connected_output =	neigh_resolve_output,
	.hh_output =		dev_queue_xmit,
	.queue_xmit =		dev_queue_xmit,
};

static struct neigh_ops arp_direct_ops = {
	.family =		AF_INET,
	.output =		dev_queue_xmit,
	.connected_output =	dev_queue_xmit,
	.hh_output =		dev_queue_xmit,
	.queue_xmit =		dev_queue_xmit,
};

struct neigh_ops arp_broken_ops = {
	.family =		AF_INET,
	.solicit =		arp_solicit,
	.error_report =		arp_error_report,
	.output =		neigh_compat_output,
	.connected_output =	neigh_compat_output,
	.hh_output =		dev_queue_xmit,
	.queue_xmit =		dev_queue_xmit,
};

struct neigh_table arp_tbl = {
	.family =	AF_INET,
	.entry_size =	sizeof(struct neighbour) + 4,
	.key_len =	4,
	.hash =		arp_hash,
	.constructor =	arp_constructor,
	.proxy_redo =	parp_redo,
	.id =		"arp_cache",
	.parms = {
		.tbl =			&arp_tbl,
		.base_reachable_time =	30 * HZ,
		.retrans_time =	1 * HZ,
		.gc_staletime =	60 * HZ,
		.reachable_time =		30 * HZ,
		.delay_probe_time =	5 * HZ,
		.queue_len =		3,
		.ucast_probes =	3,
		.mcast_probes =	3,
		.anycast_delay =	1 * HZ,
		.proxy_delay =		(8 * HZ) / 10,
		.proxy_qlen =		64,
		.locktime =		1 * HZ,
	},
	.gc_interval =	30 * HZ,
	.gc_thresh1 =	128,
	.gc_thresh2 =	512,
	.gc_thresh3 =	1024,
};

200
int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
L
Linus Torvalds 已提交
201 202 203 204 205 206
{
	switch (dev->type) {
	case ARPHRD_ETHER:
	case ARPHRD_FDDI:
	case ARPHRD_IEEE802:
		ip_eth_mc_map(addr, haddr);
207
		return 0;
L
Linus Torvalds 已提交
208 209 210 211
	case ARPHRD_IEEE802_TR:
		ip_tr_mc_map(addr, haddr);
		return 0;
	case ARPHRD_INFINIBAND:
212
		ip_ib_mc_map(addr, dev->broadcast, haddr);
L
Linus Torvalds 已提交
213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230
		return 0;
	default:
		if (dir) {
			memcpy(haddr, dev->broadcast, dev->addr_len);
			return 0;
		}
	}
	return -EINVAL;
}


static u32 arp_hash(const void *pkey, const struct net_device *dev)
{
	return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd);
}

static int arp_constructor(struct neighbour *neigh)
{
A
Al Viro 已提交
231
	__be32 addr = *(__be32*)neigh->primary_key;
L
Linus Torvalds 已提交
232 233 234 235 236
	struct net_device *dev = neigh->dev;
	struct in_device *in_dev;
	struct neigh_parms *parms;

	rcu_read_lock();
237
	in_dev = __in_dev_get_rcu(dev);
L
Linus Torvalds 已提交
238 239 240 241 242
	if (in_dev == NULL) {
		rcu_read_unlock();
		return -EINVAL;
	}

243
	neigh->type = inet_addr_type(dev_net(dev), addr);
244

L
Linus Torvalds 已提交
245 246 247 248 249
	parms = in_dev->arp_parms;
	__neigh_parms_put(neigh->parms);
	neigh->parms = neigh_parms_clone(parms);
	rcu_read_unlock();

250
	if (!dev->header_ops) {
L
Linus Torvalds 已提交
251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284
		neigh->nud_state = NUD_NOARP;
		neigh->ops = &arp_direct_ops;
		neigh->output = neigh->ops->queue_xmit;
	} else {
		/* Good devices (checked by reading texts, but only Ethernet is
		   tested)

		   ARPHRD_ETHER: (ethernet, apfddi)
		   ARPHRD_FDDI: (fddi)
		   ARPHRD_IEEE802: (tr)
		   ARPHRD_METRICOM: (strip)
		   ARPHRD_ARCNET:
		   etc. etc. etc.

		   ARPHRD_IPDDP will also work, if author repairs it.
		   I did not it, because this driver does not work even
		   in old paradigm.
		 */

#if 1
		/* So... these "amateur" devices are hopeless.
		   The only thing, that I can say now:
		   It is very sad that we need to keep ugly obsolete
		   code to make them happy.

		   They should be moved to more reasonable state, now
		   they use rebuild_header INSTEAD OF hard_start_xmit!!!
		   Besides that, they are sort of out of date
		   (a lot of redundant clones/copies, useless in 2.1),
		   I wonder why people believe that they work.
		 */
		switch (dev->type) {
		default:
			break;
285
		case ARPHRD_ROSE:
L
Linus Torvalds 已提交
286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
		case ARPHRD_AX25:
#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
		case ARPHRD_NETROM:
#endif
			neigh->ops = &arp_broken_ops;
			neigh->output = neigh->ops->output;
			return 0;
#endif
		;}
#endif
		if (neigh->type == RTN_MULTICAST) {
			neigh->nud_state = NUD_NOARP;
			arp_mc_map(addr, neigh->ha, dev, 1);
		} else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
			neigh->nud_state = NUD_NOARP;
			memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
		} else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) {
			neigh->nud_state = NUD_NOARP;
			memcpy(neigh->ha, dev->broadcast, dev->addr_len);
		}
307 308

		if (dev->header_ops->cache)
L
Linus Torvalds 已提交
309 310 311
			neigh->ops = &arp_hh_ops;
		else
			neigh->ops = &arp_generic_ops;
312

L
Linus Torvalds 已提交
313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328
		if (neigh->nud_state&NUD_VALID)
			neigh->output = neigh->ops->connected_output;
		else
			neigh->output = neigh->ops->output;
	}
	return 0;
}

static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
{
	dst_link_failure(skb);
	kfree_skb(skb);
}

static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
{
A
Al Viro 已提交
329
	__be32 saddr = 0;
L
Linus Torvalds 已提交
330 331
	u8  *dst_ha = NULL;
	struct net_device *dev = neigh->dev;
A
Al Viro 已提交
332
	__be32 target = *(__be32*)neigh->primary_key;
L
Linus Torvalds 已提交
333 334 335 336 337 338 339 340 341
	int probes = atomic_read(&neigh->probes);
	struct in_device *in_dev = in_dev_get(dev);

	if (!in_dev)
		return;

	switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
	default:
	case 0:		/* By default announce any local IP */
342
		if (skb && inet_addr_type(dev_net(dev), ip_hdr(skb)->saddr) == RTN_LOCAL)
343
			saddr = ip_hdr(skb)->saddr;
L
Linus Torvalds 已提交
344 345 346 347
		break;
	case 1:		/* Restrict announcements of saddr in same subnet */
		if (!skb)
			break;
348
		saddr = ip_hdr(skb)->saddr;
349
		if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) {
L
Linus Torvalds 已提交
350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368
			/* saddr should be known to target */
			if (inet_addr_onlink(in_dev, target, saddr))
				break;
		}
		saddr = 0;
		break;
	case 2:		/* Avoid secondary IPs, get a primary/preferred one */
		break;
	}

	if (in_dev)
		in_dev_put(in_dev);
	if (!saddr)
		saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);

	if ((probes -= neigh->parms->ucast_probes) < 0) {
		if (!(neigh->nud_state&NUD_VALID))
			printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n");
		dst_ha = neigh->ha;
369
		read_lock_bh(&neigh->lock);
L
Linus Torvalds 已提交
370 371 372 373 374 375 376 377 378
	} else if ((probes -= neigh->parms->app_probes) < 0) {
#ifdef CONFIG_ARPD
		neigh_app_ns(neigh);
#endif
		return;
	}

	arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
		 dst_ha, dev->dev_addr, NULL);
379 380
	if (dst_ha)
		read_unlock_bh(&neigh->lock);
L
Linus Torvalds 已提交
381 382
}

383
static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
L
Linus Torvalds 已提交
384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413
{
	int scope;

	switch (IN_DEV_ARP_IGNORE(in_dev)) {
	case 0:	/* Reply, the tip is already validated */
		return 0;
	case 1:	/* Reply only if tip is configured on the incoming interface */
		sip = 0;
		scope = RT_SCOPE_HOST;
		break;
	case 2:	/*
		 * Reply only if tip is configured on the incoming interface
		 * and is in same subnet as sip
		 */
		scope = RT_SCOPE_HOST;
		break;
	case 3:	/* Do not reply for scope host addresses */
		sip = 0;
		scope = RT_SCOPE_LINK;
		break;
	case 4:	/* Reserved */
	case 5:
	case 6:
	case 7:
		return 0;
	case 8:	/* Do not reply */
		return 1;
	default:
		return 0;
	}
414
	return !inet_confirm_addr(in_dev, sip, tip, scope);
L
Linus Torvalds 已提交
415 416
}

417
static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
L
Linus Torvalds 已提交
418 419 420 421
{
	struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip,
						 .saddr = tip } } };
	struct rtable *rt;
422
	int flag = 0;
L
Linus Torvalds 已提交
423
	/*unsigned long now; */
424
	struct net *net = dev_net(dev);
L
Linus Torvalds 已提交
425

426
	if (ip_route_output_key(net, &rt, &fl) < 0)
L
Linus Torvalds 已提交
427
		return 1;
428
	if (rt->u.dst.dev != dev) {
429
		NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
L
Linus Torvalds 已提交
430
		flag = 1;
431 432 433 434
	}
	ip_rt_put(rt);
	return flag;
}
L
Linus Torvalds 已提交
435 436 437 438 439 440 441 442 443 444 445 446

/* OBSOLETE FUNCTIONS */

/*
 *	Find an arp mapping in the cache. If not found, post a request.
 *
 *	It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
 *	even if it exists. It is supposed that skb->dev was mangled
 *	by a virtual device (eql, shaper). Nobody but broken devices
 *	is allowed to use this function, it is scheduled to be removed. --ANK
 */

447
static int arp_set_predefined(int addr_hint, unsigned char * haddr, __be32 paddr, struct net_device * dev)
L
Linus Torvalds 已提交
448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467
{
	switch (addr_hint) {
	case RTN_LOCAL:
		printk(KERN_DEBUG "ARP: arp called for own IP address\n");
		memcpy(haddr, dev->dev_addr, dev->addr_len);
		return 1;
	case RTN_MULTICAST:
		arp_mc_map(paddr, haddr, dev, 1);
		return 1;
	case RTN_BROADCAST:
		memcpy(haddr, dev->broadcast, dev->addr_len);
		return 1;
	}
	return 0;
}


int arp_find(unsigned char *haddr, struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
A
Al Viro 已提交
468
	__be32 paddr;
L
Linus Torvalds 已提交
469 470 471 472 473 474 475 476
	struct neighbour *n;

	if (!skb->dst) {
		printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
		kfree_skb(skb);
		return 1;
	}

E
Eric Dumazet 已提交
477
	paddr = skb_rtable(skb)->rt_gateway;
L
Linus Torvalds 已提交
478

479
	if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, paddr, dev))
L
Linus Torvalds 已提交
480 481 482 483 484 485 486 487
		return 0;

	n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);

	if (n) {
		n->used = jiffies;
		if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) {
			read_lock_bh(&n->lock);
488
			memcpy(haddr, n->ha, dev->addr_len);
L
Linus Torvalds 已提交
489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508
			read_unlock_bh(&n->lock);
			neigh_release(n);
			return 0;
		}
		neigh_release(n);
	} else
		kfree_skb(skb);
	return 1;
}

/* END OF OBSOLETE FUNCTIONS */

int arp_bind_neighbour(struct dst_entry *dst)
{
	struct net_device *dev = dst->dev;
	struct neighbour *n = dst->neighbour;

	if (dev == NULL)
		return -EINVAL;
	if (n == NULL) {
J
Jianjun Kong 已提交
509
		__be32 nexthop = ((struct rtable *)dst)->rt_gateway;
L
Linus Torvalds 已提交
510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557
		if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT))
			nexthop = 0;
		n = __neigh_lookup_errno(
#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
		    dev->type == ARPHRD_ATM ? clip_tbl_hook :
#endif
		    &arp_tbl, &nexthop, dev);
		if (IS_ERR(n))
			return PTR_ERR(n);
		dst->neighbour = n;
	}
	return 0;
}

/*
 * Check if we can use proxy ARP for this path
 */

static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
{
	struct in_device *out_dev;
	int imi, omi = -1;

	if (!IN_DEV_PROXY_ARP(in_dev))
		return 0;

	if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0)
		return 1;
	if (imi == -1)
		return 0;

	/* place to check for proxy_arp for routes */

	if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) {
		omi = IN_DEV_MEDIUM_ID(out_dev);
		in_dev_put(out_dev);
	}
	return (omi != imi && omi != -1);
}

/*
 *	Interface to link layer: send routine and receive handler.
 */

/*
 *	Create an arp packet. If (dest_hw == NULL), we create a broadcast
 *	message.
 */
558 559
struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
			   struct net_device *dev, __be32 src_ip,
560 561 562
			   const unsigned char *dest_hw,
			   const unsigned char *src_hw,
			   const unsigned char *target_hw)
L
Linus Torvalds 已提交
563 564 565 566 567 568 569 570
{
	struct sk_buff *skb;
	struct arphdr *arp;
	unsigned char *arp_ptr;

	/*
	 *	Allocate a buffer
	 */
571

572
	skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
L
Linus Torvalds 已提交
573 574 575 576
	if (skb == NULL)
		return NULL;

	skb_reserve(skb, LL_RESERVED_SPACE(dev));
577
	skb_reset_network_header(skb);
578
	arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
L
Linus Torvalds 已提交
579 580 581 582 583 584 585 586 587 588
	skb->dev = dev;
	skb->protocol = htons(ETH_P_ARP);
	if (src_hw == NULL)
		src_hw = dev->dev_addr;
	if (dest_hw == NULL)
		dest_hw = dev->broadcast;

	/*
	 *	Fill the device header for the ARP frame
	 */
589
	if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
L
Linus Torvalds 已提交
590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642
		goto out;

	/*
	 * Fill out the arp protocol part.
	 *
	 * The arp hardware type should match the device type, except for FDDI,
	 * which (according to RFC 1390) should always equal 1 (Ethernet).
	 */
	/*
	 *	Exceptions everywhere. AX.25 uses the AX.25 PID value not the
	 *	DIX code for the protocol. Make these device structure fields.
	 */
	switch (dev->type) {
	default:
		arp->ar_hrd = htons(dev->type);
		arp->ar_pro = htons(ETH_P_IP);
		break;

#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
	case ARPHRD_AX25:
		arp->ar_hrd = htons(ARPHRD_AX25);
		arp->ar_pro = htons(AX25_P_IP);
		break;

#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
	case ARPHRD_NETROM:
		arp->ar_hrd = htons(ARPHRD_NETROM);
		arp->ar_pro = htons(AX25_P_IP);
		break;
#endif
#endif

#ifdef CONFIG_FDDI
	case ARPHRD_FDDI:
		arp->ar_hrd = htons(ARPHRD_ETHER);
		arp->ar_pro = htons(ETH_P_IP);
		break;
#endif
#ifdef CONFIG_TR
	case ARPHRD_IEEE802_TR:
		arp->ar_hrd = htons(ARPHRD_IEEE802);
		arp->ar_pro = htons(ETH_P_IP);
		break;
#endif
	}

	arp->ar_hln = dev->addr_len;
	arp->ar_pln = 4;
	arp->ar_op = htons(type);

	arp_ptr=(unsigned char *)(arp+1);

	memcpy(arp_ptr, src_hw, dev->addr_len);
J
Jianjun Kong 已提交
643 644 645
	arp_ptr += dev->addr_len;
	memcpy(arp_ptr, &src_ip, 4);
	arp_ptr += 4;
L
Linus Torvalds 已提交
646 647 648 649
	if (target_hw != NULL)
		memcpy(arp_ptr, target_hw, dev->addr_len);
	else
		memset(arp_ptr, 0, dev->addr_len);
J
Jianjun Kong 已提交
650
	arp_ptr += dev->addr_len;
L
Linus Torvalds 已提交
651 652 653 654 655 656 657 658 659 660 661 662 663 664 665
	memcpy(arp_ptr, &dest_ip, 4);

	return skb;

out:
	kfree_skb(skb);
	return NULL;
}

/*
 *	Send an arp packet.
 */
void arp_xmit(struct sk_buff *skb)
{
	/* Send it off, maybe filter it using firewalling first.  */
666
	NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
L
Linus Torvalds 已提交
667 668 669 670 671
}

/*
 *	Create and send an arp packet.
 */
672 673
void arp_send(int type, int ptype, __be32 dest_ip,
	      struct net_device *dev, __be32 src_ip,
674 675
	      const unsigned char *dest_hw, const unsigned char *src_hw,
	      const unsigned char *target_hw)
L
Linus Torvalds 已提交
676 677 678 679 680 681
{
	struct sk_buff *skb;

	/*
	 *	No arp on this interface.
	 */
682

L
Linus Torvalds 已提交
683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705
	if (dev->flags&IFF_NOARP)
		return;

	skb = arp_create(type, ptype, dest_ip, dev, src_ip,
			 dest_hw, src_hw, target_hw);
	if (skb == NULL) {
		return;
	}

	arp_xmit(skb);
}

/*
 *	Process an arp request.
 */

static int arp_process(struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
	struct in_device *in_dev = in_dev_get(dev);
	struct arphdr *arp;
	unsigned char *arp_ptr;
	struct rtable *rt;
M
Mark Ryden 已提交
706
	unsigned char *sha;
A
Al Viro 已提交
707
	__be32 sip, tip;
L
Linus Torvalds 已提交
708 709 710
	u16 dev_type = dev->type;
	int addr_type;
	struct neighbour *n;
711
	struct net *net = dev_net(dev);
L
Linus Torvalds 已提交
712 713 714 715 716 717 718 719

	/* arp_rcv below verifies the ARP header and verifies the device
	 * is ARP'able.
	 */

	if (in_dev == NULL)
		goto out;

720
	arp = arp_hdr(skb);
L
Linus Torvalds 已提交
721 722

	switch (dev_type) {
723
	default:
L
Linus Torvalds 已提交
724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773
		if (arp->ar_pro != htons(ETH_P_IP) ||
		    htons(dev_type) != arp->ar_hrd)
			goto out;
		break;
	case ARPHRD_ETHER:
	case ARPHRD_IEEE802_TR:
	case ARPHRD_FDDI:
	case ARPHRD_IEEE802:
		/*
		 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
		 * devices, according to RFC 2625) devices will accept ARP
		 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
		 * This is the case also of FDDI, where the RFC 1390 says that
		 * FDDI devices should accept ARP hardware of (1) Ethernet,
		 * however, to be more robust, we'll accept both 1 (Ethernet)
		 * or 6 (IEEE 802.2)
		 */
		if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
		     arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
		    arp->ar_pro != htons(ETH_P_IP))
			goto out;
		break;
	case ARPHRD_AX25:
		if (arp->ar_pro != htons(AX25_P_IP) ||
		    arp->ar_hrd != htons(ARPHRD_AX25))
			goto out;
		break;
	case ARPHRD_NETROM:
		if (arp->ar_pro != htons(AX25_P_IP) ||
		    arp->ar_hrd != htons(ARPHRD_NETROM))
			goto out;
		break;
	}

	/* Understand only these message types */

	if (arp->ar_op != htons(ARPOP_REPLY) &&
	    arp->ar_op != htons(ARPOP_REQUEST))
		goto out;

/*
 *	Extract fields
 */
	arp_ptr= (unsigned char *)(arp+1);
	sha	= arp_ptr;
	arp_ptr += dev->addr_len;
	memcpy(&sip, arp_ptr, 4);
	arp_ptr += 4;
	arp_ptr += dev->addr_len;
	memcpy(&tip, arp_ptr, 4);
774
/*
L
Linus Torvalds 已提交
775 776 777
 *	Check for bad requests for 127.x.x.x and requests for multicast
 *	addresses.  If this is one such, delete it.
 */
778
	if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
L
Linus Torvalds 已提交
779 780 781 782 783 784 785 786 787 788 789 790
		goto out;

/*
 *     Special case: We must set Frame Relay source Q.922 address
 */
	if (dev_type == ARPHRD_DLCI)
		sha = dev->broadcast;

/*
 *  Process entry.  The idea here is we want to send a reply if it is a
 *  request for us or if it is a request for someone else that we hold
 *  a proxy for.  We want to add an entry to our cache if it is a reply
791 792 793 794
 *  to us or if it is a request for our address.
 *  (The assumption for this last is that if someone is requesting our
 *  address, they are probably intending to talk to us, so it saves time
 *  if we cache their address.  Their address is also probably not in
L
Linus Torvalds 已提交
795
 *  our cache, since ours is not in their cache.)
796
 *
L
Linus Torvalds 已提交
797 798 799
 *  Putting this another way, we only care about replies if they are to
 *  us, in which case we add them to the cache.  For requests, we care
 *  about those for us and those for our proxies.  We reply to both,
800
 *  and in the case of requests for us we add the requester to the arp
L
Linus Torvalds 已提交
801 802 803
 *  cache.
 */

804 805 806 807 808
	/*
	 *  Special case: IPv4 duplicate address detection packet (RFC2131)
	 *  and Gratuitous ARP/ARP Announce. (RFC3927, Section 2.4)
	 */
	if (sip == 0 || tip == sip) {
L
Linus Torvalds 已提交
809
		if (arp->ar_op == htons(ARPOP_REQUEST) &&
810
		    inet_addr_type(net, tip) == RTN_LOCAL &&
811
		    !arp_ignore(in_dev, sip, tip))
812 813
			arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
				 dev->dev_addr, sha);
L
Linus Torvalds 已提交
814 815 816 817 818 819
		goto out;
	}

	if (arp->ar_op == htons(ARPOP_REQUEST) &&
	    ip_route_input(skb, tip, sip, 0, dev) == 0) {

E
Eric Dumazet 已提交
820
		rt = skb_rtable(skb);
L
Linus Torvalds 已提交
821 822 823
		addr_type = rt->rt_type;

		if (addr_type == RTN_LOCAL) {
824 825 826 827 828 829 830 831 832
			int dont_send = 0;

			if (!dont_send)
				dont_send |= arp_ignore(in_dev,sip,tip);
			if (!dont_send && IN_DEV_ARPFILTER(in_dev))
				dont_send |= arp_filter(sip,tip,dev);
			if (!dont_send) {
				n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
				if (n) {
L
Linus Torvalds 已提交
833
					arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
834 835
					neigh_release(n);
				}
L
Linus Torvalds 已提交
836 837 838
			}
			goto out;
		} else if (IN_DEV_FORWARD(in_dev)) {
839
			    if (addr_type == RTN_UNICAST  && rt->u.dst.dev != dev &&
840
			     (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) {
L
Linus Torvalds 已提交
841 842 843 844
				n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
				if (n)
					neigh_release(n);

845
				if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
L
Linus Torvalds 已提交
846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862
				    skb->pkt_type == PACKET_HOST ||
				    in_dev->arp_parms->proxy_delay == 0) {
					arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
				} else {
					pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb);
					in_dev_put(in_dev);
					return 0;
				}
				goto out;
			}
		}
	}

	/* Update our ARP tables */

	n = __neigh_lookup(&arp_tbl, &sip, dev, 0);

863
	if (IPV4_DEVCONF_ALL(dev_net(dev), ARP_ACCEPT)) {
864 865 866 867 868 869
		/* Unsolicited ARP is not accepted by default.
		   It is possible, that this option should be enabled for some
		   devices (strip is candidate)
		 */
		if (n == NULL &&
		    arp->ar_op == htons(ARPOP_REPLY) &&
870
		    inet_addr_type(net, sip) == RTN_UNICAST)
871
			n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
872
	}
L
Linus Torvalds 已提交
873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897

	if (n) {
		int state = NUD_REACHABLE;
		int override;

		/* If several different ARP replies follows back-to-back,
		   use the FIRST one. It is possible, if several proxy
		   agents are active. Taking the first reply prevents
		   arp trashing and chooses the fastest router.
		 */
		override = time_after(jiffies, n->updated + n->parms->locktime);

		/* Broadcast replies and request packets
		   do not assert neighbour reachability.
		 */
		if (arp->ar_op != htons(ARPOP_REPLY) ||
		    skb->pkt_type != PACKET_HOST)
			state = NUD_STALE;
		neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0);
		neigh_release(n);
	}

out:
	if (in_dev)
		in_dev_put(in_dev);
898
	consume_skb(skb);
L
Linus Torvalds 已提交
899 900 901
	return 0;
}

H
Herbert Xu 已提交
902 903 904 905 906
static void parp_redo(struct sk_buff *skb)
{
	arp_process(skb);
}

L
Linus Torvalds 已提交
907 908 909 910 911

/*
 *	Receive an arp request from the device layer.
 */

A
Adrian Bunk 已提交
912 913
static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
		   struct packet_type *pt, struct net_device *orig_dev)
L
Linus Torvalds 已提交
914 915 916 917
{
	struct arphdr *arp;

	/* ARP header, plus 2 device addresses, plus 2 IP addresses.  */
918
	if (!pskb_may_pull(skb, arp_hdr_len(dev)))
L
Linus Torvalds 已提交
919 920
		goto freeskb;

921
	arp = arp_hdr(skb);
L
Linus Torvalds 已提交
922 923 924 925 926 927 928 929 930 931
	if (arp->ar_hln != dev->addr_len ||
	    dev->flags & IFF_NOARP ||
	    skb->pkt_type == PACKET_OTHERHOST ||
	    skb->pkt_type == PACKET_LOOPBACK ||
	    arp->ar_pln != 4)
		goto freeskb;

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
		goto out_of_mem;

932 933
	memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));

934
	return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
L
Linus Torvalds 已提交
935 936 937 938 939 940 941 942 943 944 945 946 947 948 949

freeskb:
	kfree_skb(skb);
out_of_mem:
	return 0;
}

/*
 *	User level interface (ioctl)
 */

/*
 *	Set (create) an ARP cache entry.
 */

950
static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
951 952
{
	if (dev == NULL) {
953
		IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
954 955 956 957 958 959 960 961 962
		return 0;
	}
	if (__in_dev_get_rtnl(dev)) {
		IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
		return 0;
	}
	return -ENXIO;
}

963 964
static int arp_req_set_public(struct net *net, struct arpreq *r,
		struct net_device *dev)
965 966 967 968 969 970 971
{
	__be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
	__be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;

	if (mask && mask != htonl(0xFFFFFFFF))
		return -EINVAL;
	if (!dev && (r->arp_flags & ATF_COM)) {
972
		dev = dev_getbyhwaddr(net, r->arp_ha.sa_family,
973 974 975 976 977
				r->arp_ha.sa_data);
		if (!dev)
			return -ENODEV;
	}
	if (mask) {
978
		if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL)
979 980 981
			return -ENOBUFS;
		return 0;
	}
982

983
	return arp_req_set_proxy(net, dev, 1);
984 985
}

986 987
static int arp_req_set(struct net *net, struct arpreq *r,
		struct net_device * dev)
L
Linus Torvalds 已提交
988
{
989
	__be32 ip;
L
Linus Torvalds 已提交
990 991 992
	struct neighbour *neigh;
	int err;

993
	if (r->arp_flags & ATF_PUBL)
994
		return arp_req_set_public(net, r, dev);
L
Linus Torvalds 已提交
995

996
	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
L
Linus Torvalds 已提交
997 998 999 1000 1001 1002
	if (r->arp_flags & ATF_PERM)
		r->arp_flags |= ATF_COM;
	if (dev == NULL) {
		struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
							 .tos = RTO_ONLINK } } };
		struct rtable * rt;
1003
		if ((err = ip_route_output_key(net, &rt, &fl)) != 0)
L
Linus Torvalds 已提交
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
			return err;
		dev = rt->u.dst.dev;
		ip_rt_put(rt);
		if (!dev)
			return -EINVAL;
	}
	switch (dev->type) {
#ifdef CONFIG_FDDI
	case ARPHRD_FDDI:
		/*
		 * According to RFC 1390, FDDI devices should accept ARP
		 * hardware types of 1 (Ethernet).  However, to be more
		 * robust, we'll accept hardware types of either 1 (Ethernet)
		 * or 6 (IEEE 802.2).
		 */
		if (r->arp_ha.sa_family != ARPHRD_FDDI &&
		    r->arp_ha.sa_family != ARPHRD_ETHER &&
		    r->arp_ha.sa_family != ARPHRD_IEEE802)
			return -EINVAL;
		break;
#endif
	default:
		if (r->arp_ha.sa_family != dev->type)
			return -EINVAL;
		break;
	}

	neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
	err = PTR_ERR(neigh);
	if (!IS_ERR(neigh)) {
		unsigned state = NUD_STALE;
		if (r->arp_flags & ATF_PERM)
			state = NUD_PERMANENT;
		err = neigh_update(neigh, (r->arp_flags&ATF_COM) ?
1038
				   r->arp_ha.sa_data : NULL, state,
L
Linus Torvalds 已提交
1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061
				   NEIGH_UPDATE_F_OVERRIDE|
				   NEIGH_UPDATE_F_ADMIN);
		neigh_release(neigh);
	}
	return err;
}

static unsigned arp_state_to_flags(struct neighbour *neigh)
{
	unsigned flags = 0;
	if (neigh->nud_state&NUD_PERMANENT)
		flags = ATF_PERM|ATF_COM;
	else if (neigh->nud_state&NUD_VALID)
		flags = ATF_COM;
	return flags;
}

/*
 *	Get an ARP cache entry.
 */

static int arp_req_get(struct arpreq *r, struct net_device *dev)
{
1062
	__be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
L
Linus Torvalds 已提交
1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
	struct neighbour *neigh;
	int err = -ENXIO;

	neigh = neigh_lookup(&arp_tbl, &ip, dev);
	if (neigh) {
		read_lock_bh(&neigh->lock);
		memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
		r->arp_flags = arp_state_to_flags(neigh);
		read_unlock_bh(&neigh->lock);
		r->arp_ha.sa_family = dev->type;
		strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
		neigh_release(neigh);
		err = 0;
	}
	return err;
}

1080 1081
static int arp_req_delete_public(struct net *net, struct arpreq *r,
		struct net_device *dev)
1082 1083 1084 1085 1086
{
	__be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
	__be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;

	if (mask == htonl(0xFFFFFFFF))
1087
		return pneigh_delete(&arp_tbl, net, &ip, dev);
1088

1089 1090 1091
	if (mask)
		return -EINVAL;

1092
	return arp_req_set_proxy(net, dev, 0);
1093 1094
}

1095 1096
static int arp_req_delete(struct net *net, struct arpreq *r,
		struct net_device * dev)
L
Linus Torvalds 已提交
1097 1098
{
	int err;
1099
	__be32 ip;
L
Linus Torvalds 已提交
1100 1101
	struct neighbour *neigh;

1102
	if (r->arp_flags & ATF_PUBL)
1103
		return arp_req_delete_public(net, r, dev);
L
Linus Torvalds 已提交
1104

1105
	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
L
Linus Torvalds 已提交
1106 1107 1108 1109
	if (dev == NULL) {
		struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
							 .tos = RTO_ONLINK } } };
		struct rtable * rt;
1110
		if ((err = ip_route_output_key(net, &rt, &fl)) != 0)
L
Linus Torvalds 已提交
1111 1112 1113 1114 1115 1116 1117 1118 1119 1120
			return err;
		dev = rt->u.dst.dev;
		ip_rt_put(rt);
		if (!dev)
			return -EINVAL;
	}
	err = -ENXIO;
	neigh = neigh_lookup(&arp_tbl, &ip, dev);
	if (neigh) {
		if (neigh->nud_state&~NUD_NOARP)
1121
			err = neigh_update(neigh, NULL, NUD_FAILED,
L
Linus Torvalds 已提交
1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132
					   NEIGH_UPDATE_F_OVERRIDE|
					   NEIGH_UPDATE_F_ADMIN);
		neigh_release(neigh);
	}
	return err;
}

/*
 *	Handle an ARP layer I/O control request.
 */

1133
int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
L
Linus Torvalds 已提交
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164
{
	int err;
	struct arpreq r;
	struct net_device *dev = NULL;

	switch (cmd) {
		case SIOCDARP:
		case SIOCSARP:
			if (!capable(CAP_NET_ADMIN))
				return -EPERM;
		case SIOCGARP:
			err = copy_from_user(&r, arg, sizeof(struct arpreq));
			if (err)
				return -EFAULT;
			break;
		default:
			return -EINVAL;
	}

	if (r.arp_pa.sa_family != AF_INET)
		return -EPFNOSUPPORT;

	if (!(r.arp_flags & ATF_PUBL) &&
	    (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB)))
		return -EINVAL;
	if (!(r.arp_flags & ATF_NETMASK))
		((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
							   htonl(0xFFFFFFFFUL);
	rtnl_lock();
	if (r.arp_dev[0]) {
		err = -ENODEV;
1165
		if ((dev = __dev_get_by_name(net, r.arp_dev)) == NULL)
L
Linus Torvalds 已提交
1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178
			goto out;

		/* Mmmm... It is wrong... ARPHRD_NETROM==0 */
		if (!r.arp_ha.sa_family)
			r.arp_ha.sa_family = dev->type;
		err = -EINVAL;
		if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
			goto out;
	} else if (cmd == SIOCGARP) {
		err = -ENODEV;
		goto out;
	}

S
Stephen Hemminger 已提交
1179
	switch (cmd) {
L
Linus Torvalds 已提交
1180
	case SIOCDARP:
1181
		err = arp_req_delete(net, &r, dev);
L
Linus Torvalds 已提交
1182 1183
		break;
	case SIOCSARP:
1184
		err = arp_req_set(net, &r, dev);
L
Linus Torvalds 已提交
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203
		break;
	case SIOCGARP:
		err = arp_req_get(&r, dev);
		if (!err && copy_to_user(arg, &r, sizeof(r)))
			err = -EFAULT;
		break;
	}
out:
	rtnl_unlock();
	return err;
}

static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;

	switch (event) {
	case NETDEV_CHANGEADDR:
		neigh_changeaddr(&arp_tbl, dev);
1204
		rt_cache_flush(dev_net(dev), 0);
L
Linus Torvalds 已提交
1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230
		break;
	default:
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block arp_netdev_notifier = {
	.notifier_call = arp_netdev_event,
};

/* Note, that it is not on notifier chain.
   It is necessary, that this routine was called after route cache will be
   flushed.
 */
void arp_ifdown(struct net_device *dev)
{
	neigh_ifdown(&arp_tbl, dev);
}


/*
 *	Called once on startup.
 */

1231
static struct packet_type arp_packet_type __read_mostly = {
1232
	.type =	cpu_to_be16(ETH_P_ARP),
L
Linus Torvalds 已提交
1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267
	.func =	arp_rcv,
};

static int arp_proc_init(void);

void __init arp_init(void)
{
	neigh_table_init(&arp_tbl);

	dev_add_pack(&arp_packet_type);
	arp_proc_init();
#ifdef CONFIG_SYSCTL
	neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4,
			      NET_IPV4_NEIGH, "ipv4", NULL, NULL);
#endif
	register_netdevice_notifier(&arp_netdev_notifier);
}

#ifdef CONFIG_PROC_FS
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)

/* ------------------------------------------------------------------------ */
/*
 *	ax25 -> ASCII conversion
 */
static char *ax2asc2(ax25_address *a, char *buf)
{
	char c, *s;
	int n;

	for (n = 0, s = buf; n < 6; n++) {
		c = (a->ax25_call[n] >> 1) & 0x7F;

		if (c != ' ') *s++ = c;
	}
1268

L
Linus Torvalds 已提交
1269 1270 1271 1272 1273 1274
	*s++ = '-';

	if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
		*s++ = '1';
		n -= 10;
	}
1275

L
Linus Torvalds 已提交
1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305
	*s++ = n + '0';
	*s++ = '\0';

	if (*buf == '\0' || *buf == '-')
	   return "*";

	return buf;

}
#endif /* CONFIG_AX25 */

#define HBUFFERLEN 30

static void arp_format_neigh_entry(struct seq_file *seq,
				   struct neighbour *n)
{
	char hbuffer[HBUFFERLEN];
	int k, j;
	char tbuf[16];
	struct net_device *dev = n->dev;
	int hatype = dev->type;

	read_lock(&n->lock);
	/* Convert hardware address to XX:XX:XX:XX ... form. */
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
	if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
		ax2asc2((ax25_address *)n->ha, hbuffer);
	else {
#endif
	for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1306 1307
		hbuffer[k++] = hex_asc_hi(n->ha[j]);
		hbuffer[k++] = hex_asc_lo(n->ha[j]);
L
Linus Torvalds 已提交
1308 1309 1310 1311 1312 1313
		hbuffer[k++] = ':';
	}
	hbuffer[--k] = 0;
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
	}
#endif
1314
	sprintf(tbuf, "%pI4", n->primary_key);
L
Linus Torvalds 已提交
1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326
	seq_printf(seq, "%-16s 0x%-10x0x%-10x%s     *        %s\n",
		   tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
	read_unlock(&n->lock);
}

static void arp_format_pneigh_entry(struct seq_file *seq,
				    struct pneigh_entry *n)
{
	struct net_device *dev = n->dev;
	int hatype = dev ? dev->type : 0;
	char tbuf[16];

1327
	sprintf(tbuf, "%pI4", n->key);
L
Linus Torvalds 已提交
1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359
	seq_printf(seq, "%-16s 0x%-10x0x%-10x%s     *        %s\n",
		   tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
		   dev ? dev->name : "*");
}

static int arp_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN) {
		seq_puts(seq, "IP address       HW type     Flags       "
			      "HW address            Mask     Device\n");
	} else {
		struct neigh_seq_state *state = seq->private;

		if (state->flags & NEIGH_SEQ_IS_PNEIGH)
			arp_format_pneigh_entry(seq, v);
		else
			arp_format_neigh_entry(seq, v);
	}

	return 0;
}

static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
{
	/* Don't want to confuse "arp -a" w/ magic entries,
	 * so we tell the generic iterator to skip NUD_NOARP.
	 */
	return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
}

/* ------------------------------------------------------------------------ */

1360
static const struct seq_operations arp_seq_ops = {
L
Linus Torvalds 已提交
1361 1362 1363 1364 1365 1366 1367 1368
	.start  = arp_seq_start,
	.next   = neigh_seq_next,
	.stop   = neigh_seq_stop,
	.show   = arp_seq_show,
};

static int arp_seq_open(struct inode *inode, struct file *file)
{
1369 1370
	return seq_open_net(inode, file, &arp_seq_ops,
			    sizeof(struct neigh_seq_state));
L
Linus Torvalds 已提交
1371 1372
}

1373
static const struct file_operations arp_seq_fops = {
L
Linus Torvalds 已提交
1374 1375 1376 1377
	.owner		= THIS_MODULE,
	.open           = arp_seq_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
1378
	.release	= seq_release_net,
L
Linus Torvalds 已提交
1379 1380
};

1381 1382

static int __net_init arp_net_init(struct net *net)
L
Linus Torvalds 已提交
1383
{
1384
	if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops))
L
Linus Torvalds 已提交
1385 1386 1387 1388
		return -ENOMEM;
	return 0;
}

1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
static void __net_exit arp_net_exit(struct net *net)
{
	proc_net_remove(net, "arp");
}

static struct pernet_operations arp_net_ops = {
	.init = arp_net_init,
	.exit = arp_net_exit,
};

static int __init arp_proc_init(void)
{
	return register_pernet_subsys(&arp_net_ops);
}

L
Linus Torvalds 已提交
1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422
#else /* CONFIG_PROC_FS */

static int __init arp_proc_init(void)
{
	return 0;
}

#endif /* CONFIG_PROC_FS */

EXPORT_SYMBOL(arp_broken_ops);
EXPORT_SYMBOL(arp_find);
EXPORT_SYMBOL(arp_create);
EXPORT_SYMBOL(arp_xmit);
EXPORT_SYMBOL(arp_send);
EXPORT_SYMBOL(arp_tbl);

#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
EXPORT_SYMBOL(clip_tbl_hook);
#endif