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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* linux/net/inet/arp.c
2 *
3 * Version: $Id: arp.c,v 1.99 2001/08/30 22:55:42 davem Exp $
4 *
5 * Copyright (C) 1994 by Florian La Roche
6 *
7 * This module implements the Address Resolution Protocol ARP (RFC 826),
8 * which is used to convert IP addresses (or in the future maybe other
9 * high-level addresses) into a low-level hardware address (like an Ethernet
10 * address).
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * Fixes:
18 * Alan Cox : Removed the Ethernet assumptions in
19 * Florian's code
20 * Alan Cox : Fixed some small errors in the ARP
21 * logic
22 * Alan Cox : Allow >4K in /proc
23 * Alan Cox : Make ARP add its own protocol entry
24 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
25 * Stephen Henson : Add AX25 support to arp_get_info()
26 * Alan Cox : Drop data when a device is downed.
27 * Alan Cox : Use init_timer().
28 * Alan Cox : Double lock fixes.
29 * Martin Seine : Move the arphdr structure
30 * to if_arp.h for compatibility.
31 * with BSD based programs.
32 * Andrew Tridgell : Added ARP netmask code and
33 * re-arranged proxy handling.
34 * Alan Cox : Changed to use notifiers.
35 * Niibe Yutaka : Reply for this device or proxies only.
36 * Alan Cox : Don't proxy across hardware types!
37 * Jonathan Naylor : Added support for NET/ROM.
38 * Mike Shaver : RFC1122 checks.
39 * Jonathan Naylor : Only lookup the hardware address for
40 * the correct hardware type.
41 * Germano Caronni : Assorted subtle races.
42 * Craig Schlenter : Don't modify permanent entry
43 * during arp_rcv.
44 * Russ Nelson : Tidied up a few bits.
45 * Alexey Kuznetsov: Major changes to caching and behaviour,
46 * eg intelligent arp probing and
47 * generation
48 * of host down events.
49 * Alan Cox : Missing unlock in device events.
50 * Eckes : ARP ioctl control errors.
51 * Alexey Kuznetsov: Arp free fix.
52 * Manuel Rodriguez: Gratuitous ARP.
53 * Jonathan Layes : Added arpd support through kerneld
54 * message queue (960314)
55 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
56 * Mike McLagan : Routing by source
57 * Stuart Cheshire : Metricom and grat arp fixes
58 * *** FOR 2.1 clean this up ***
59 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
60 * Alan Cox : Took the AP1000 nasty FDDI hack and
61 * folded into the mainstream FDDI code.
62 * Ack spit, Linus how did you allow that
63 * one in...
64 * Jes Sorensen : Make FDDI work again in 2.1.x and
65 * clean up the APFDDI & gen. FDDI bits.
66 * Alexey Kuznetsov: new arp state machine;
67 * now it is in net/core/neighbour.c.
68 * Krzysztof Halasa: Added Frame Relay ARP support.
69 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
70 * Shmulik Hen: Split arp_send to arp_create and
71 * arp_xmit so intermediate drivers like
72 * bonding can change the skb before
73 * sending (e.g. insert 8021q tag).
74 * Harald Welte : convert to make use of jenkins hash
75 */
76
77#include <linux/module.h>
78#include <linux/types.h>
79#include <linux/string.h>
80#include <linux/kernel.h>
81#include <linux/sched.h>
Randy Dunlap4fc268d2006-01-11 12:17:47 -080082#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070083#include <linux/config.h>
84#include <linux/socket.h>
85#include <linux/sockios.h>
86#include <linux/errno.h>
87#include <linux/in.h>
88#include <linux/mm.h>
89#include <linux/inet.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020090#include <linux/inetdevice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070091#include <linux/netdevice.h>
92#include <linux/etherdevice.h>
93#include <linux/fddidevice.h>
94#include <linux/if_arp.h>
95#include <linux/trdevice.h>
96#include <linux/skbuff.h>
97#include <linux/proc_fs.h>
98#include <linux/seq_file.h>
99#include <linux/stat.h>
100#include <linux/init.h>
101#include <linux/net.h>
102#include <linux/rcupdate.h>
103#include <linux/jhash.h>
104#ifdef CONFIG_SYSCTL
105#include <linux/sysctl.h>
106#endif
107
108#include <net/ip.h>
109#include <net/icmp.h>
110#include <net/route.h>
111#include <net/protocol.h>
112#include <net/tcp.h>
113#include <net/sock.h>
114#include <net/arp.h>
115#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
116#include <net/ax25.h>
117#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
118#include <net/netrom.h>
119#endif
120#endif
121#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
122#include <net/atmclip.h>
123struct neigh_table *clip_tbl_hook;
124#endif
125
126#include <asm/system.h>
127#include <asm/uaccess.h>
128
129#include <linux/netfilter_arp.h>
130
131/*
132 * Interface to generic neighbour cache.
133 */
134static u32 arp_hash(const void *pkey, const struct net_device *dev);
135static int arp_constructor(struct neighbour *neigh);
136static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
137static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
138static void parp_redo(struct sk_buff *skb);
139
140static struct neigh_ops arp_generic_ops = {
141 .family = AF_INET,
142 .solicit = arp_solicit,
143 .error_report = arp_error_report,
144 .output = neigh_resolve_output,
145 .connected_output = neigh_connected_output,
146 .hh_output = dev_queue_xmit,
147 .queue_xmit = dev_queue_xmit,
148};
149
150static struct neigh_ops arp_hh_ops = {
151 .family = AF_INET,
152 .solicit = arp_solicit,
153 .error_report = arp_error_report,
154 .output = neigh_resolve_output,
155 .connected_output = neigh_resolve_output,
156 .hh_output = dev_queue_xmit,
157 .queue_xmit = dev_queue_xmit,
158};
159
160static struct neigh_ops arp_direct_ops = {
161 .family = AF_INET,
162 .output = dev_queue_xmit,
163 .connected_output = dev_queue_xmit,
164 .hh_output = dev_queue_xmit,
165 .queue_xmit = dev_queue_xmit,
166};
167
168struct neigh_ops arp_broken_ops = {
169 .family = AF_INET,
170 .solicit = arp_solicit,
171 .error_report = arp_error_report,
172 .output = neigh_compat_output,
173 .connected_output = neigh_compat_output,
174 .hh_output = dev_queue_xmit,
175 .queue_xmit = dev_queue_xmit,
176};
177
178struct neigh_table arp_tbl = {
179 .family = AF_INET,
180 .entry_size = sizeof(struct neighbour) + 4,
181 .key_len = 4,
182 .hash = arp_hash,
183 .constructor = arp_constructor,
184 .proxy_redo = parp_redo,
185 .id = "arp_cache",
186 .parms = {
187 .tbl = &arp_tbl,
188 .base_reachable_time = 30 * HZ,
189 .retrans_time = 1 * HZ,
190 .gc_staletime = 60 * HZ,
191 .reachable_time = 30 * HZ,
192 .delay_probe_time = 5 * HZ,
193 .queue_len = 3,
194 .ucast_probes = 3,
195 .mcast_probes = 3,
196 .anycast_delay = 1 * HZ,
197 .proxy_delay = (8 * HZ) / 10,
198 .proxy_qlen = 64,
199 .locktime = 1 * HZ,
200 },
201 .gc_interval = 30 * HZ,
202 .gc_thresh1 = 128,
203 .gc_thresh2 = 512,
204 .gc_thresh3 = 1024,
205};
206
207int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir)
208{
209 switch (dev->type) {
210 case ARPHRD_ETHER:
211 case ARPHRD_FDDI:
212 case ARPHRD_IEEE802:
213 ip_eth_mc_map(addr, haddr);
214 return 0;
215 case ARPHRD_IEEE802_TR:
216 ip_tr_mc_map(addr, haddr);
217 return 0;
218 case ARPHRD_INFINIBAND:
219 ip_ib_mc_map(addr, haddr);
220 return 0;
221 default:
222 if (dir) {
223 memcpy(haddr, dev->broadcast, dev->addr_len);
224 return 0;
225 }
226 }
227 return -EINVAL;
228}
229
230
231static u32 arp_hash(const void *pkey, const struct net_device *dev)
232{
233 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd);
234}
235
236static int arp_constructor(struct neighbour *neigh)
237{
238 u32 addr = *(u32*)neigh->primary_key;
239 struct net_device *dev = neigh->dev;
240 struct in_device *in_dev;
241 struct neigh_parms *parms;
242
243 neigh->type = inet_addr_type(addr);
244
245 rcu_read_lock();
Herbert Xue5ed6392005-10-03 14:35:55 -0700246 in_dev = __in_dev_get_rcu(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 if (in_dev == NULL) {
248 rcu_read_unlock();
249 return -EINVAL;
250 }
251
252 parms = in_dev->arp_parms;
253 __neigh_parms_put(neigh->parms);
254 neigh->parms = neigh_parms_clone(parms);
255 rcu_read_unlock();
256
257 if (dev->hard_header == NULL) {
258 neigh->nud_state = NUD_NOARP;
259 neigh->ops = &arp_direct_ops;
260 neigh->output = neigh->ops->queue_xmit;
261 } else {
262 /* Good devices (checked by reading texts, but only Ethernet is
263 tested)
264
265 ARPHRD_ETHER: (ethernet, apfddi)
266 ARPHRD_FDDI: (fddi)
267 ARPHRD_IEEE802: (tr)
268 ARPHRD_METRICOM: (strip)
269 ARPHRD_ARCNET:
270 etc. etc. etc.
271
272 ARPHRD_IPDDP will also work, if author repairs it.
273 I did not it, because this driver does not work even
274 in old paradigm.
275 */
276
277#if 1
278 /* So... these "amateur" devices are hopeless.
279 The only thing, that I can say now:
280 It is very sad that we need to keep ugly obsolete
281 code to make them happy.
282
283 They should be moved to more reasonable state, now
284 they use rebuild_header INSTEAD OF hard_start_xmit!!!
285 Besides that, they are sort of out of date
286 (a lot of redundant clones/copies, useless in 2.1),
287 I wonder why people believe that they work.
288 */
289 switch (dev->type) {
290 default:
291 break;
292 case ARPHRD_ROSE:
293#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
294 case ARPHRD_AX25:
295#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
296 case ARPHRD_NETROM:
297#endif
298 neigh->ops = &arp_broken_ops;
299 neigh->output = neigh->ops->output;
300 return 0;
301#endif
302 ;}
303#endif
304 if (neigh->type == RTN_MULTICAST) {
305 neigh->nud_state = NUD_NOARP;
306 arp_mc_map(addr, neigh->ha, dev, 1);
307 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
308 neigh->nud_state = NUD_NOARP;
309 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
310 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) {
311 neigh->nud_state = NUD_NOARP;
312 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
313 }
314 if (dev->hard_header_cache)
315 neigh->ops = &arp_hh_ops;
316 else
317 neigh->ops = &arp_generic_ops;
318 if (neigh->nud_state&NUD_VALID)
319 neigh->output = neigh->ops->connected_output;
320 else
321 neigh->output = neigh->ops->output;
322 }
323 return 0;
324}
325
326static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
327{
328 dst_link_failure(skb);
329 kfree_skb(skb);
330}
331
332static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
333{
334 u32 saddr = 0;
335 u8 *dst_ha = NULL;
336 struct net_device *dev = neigh->dev;
337 u32 target = *(u32*)neigh->primary_key;
338 int probes = atomic_read(&neigh->probes);
339 struct in_device *in_dev = in_dev_get(dev);
340
341 if (!in_dev)
342 return;
343
344 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
345 default:
346 case 0: /* By default announce any local IP */
347 if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL)
348 saddr = skb->nh.iph->saddr;
349 break;
350 case 1: /* Restrict announcements of saddr in same subnet */
351 if (!skb)
352 break;
353 saddr = skb->nh.iph->saddr;
354 if (inet_addr_type(saddr) == RTN_LOCAL) {
355 /* saddr should be known to target */
356 if (inet_addr_onlink(in_dev, target, saddr))
357 break;
358 }
359 saddr = 0;
360 break;
361 case 2: /* Avoid secondary IPs, get a primary/preferred one */
362 break;
363 }
364
365 if (in_dev)
366 in_dev_put(in_dev);
367 if (!saddr)
368 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
369
370 if ((probes -= neigh->parms->ucast_probes) < 0) {
371 if (!(neigh->nud_state&NUD_VALID))
372 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n");
373 dst_ha = neigh->ha;
374 read_lock_bh(&neigh->lock);
375 } else if ((probes -= neigh->parms->app_probes) < 0) {
376#ifdef CONFIG_ARPD
377 neigh_app_ns(neigh);
378#endif
379 return;
380 }
381
382 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
383 dst_ha, dev->dev_addr, NULL);
384 if (dst_ha)
385 read_unlock_bh(&neigh->lock);
386}
387
388static int arp_ignore(struct in_device *in_dev, struct net_device *dev,
389 u32 sip, u32 tip)
390{
391 int scope;
392
393 switch (IN_DEV_ARP_IGNORE(in_dev)) {
394 case 0: /* Reply, the tip is already validated */
395 return 0;
396 case 1: /* Reply only if tip is configured on the incoming interface */
397 sip = 0;
398 scope = RT_SCOPE_HOST;
399 break;
400 case 2: /*
401 * Reply only if tip is configured on the incoming interface
402 * and is in same subnet as sip
403 */
404 scope = RT_SCOPE_HOST;
405 break;
406 case 3: /* Do not reply for scope host addresses */
407 sip = 0;
408 scope = RT_SCOPE_LINK;
409 dev = NULL;
410 break;
411 case 4: /* Reserved */
412 case 5:
413 case 6:
414 case 7:
415 return 0;
416 case 8: /* Do not reply */
417 return 1;
418 default:
419 return 0;
420 }
421 return !inet_confirm_addr(dev, sip, tip, scope);
422}
423
424static int arp_filter(__u32 sip, __u32 tip, struct net_device *dev)
425{
426 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip,
427 .saddr = tip } } };
428 struct rtable *rt;
429 int flag = 0;
430 /*unsigned long now; */
431
432 if (ip_route_output_key(&rt, &fl) < 0)
433 return 1;
434 if (rt->u.dst.dev != dev) {
435 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER);
436 flag = 1;
437 }
438 ip_rt_put(rt);
439 return flag;
440}
441
442/* OBSOLETE FUNCTIONS */
443
444/*
445 * Find an arp mapping in the cache. If not found, post a request.
446 *
447 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
448 * even if it exists. It is supposed that skb->dev was mangled
449 * by a virtual device (eql, shaper). Nobody but broken devices
450 * is allowed to use this function, it is scheduled to be removed. --ANK
451 */
452
453static int arp_set_predefined(int addr_hint, unsigned char * haddr, u32 paddr, struct net_device * dev)
454{
455 switch (addr_hint) {
456 case RTN_LOCAL:
457 printk(KERN_DEBUG "ARP: arp called for own IP address\n");
458 memcpy(haddr, dev->dev_addr, dev->addr_len);
459 return 1;
460 case RTN_MULTICAST:
461 arp_mc_map(paddr, haddr, dev, 1);
462 return 1;
463 case RTN_BROADCAST:
464 memcpy(haddr, dev->broadcast, dev->addr_len);
465 return 1;
466 }
467 return 0;
468}
469
470
471int arp_find(unsigned char *haddr, struct sk_buff *skb)
472{
473 struct net_device *dev = skb->dev;
474 u32 paddr;
475 struct neighbour *n;
476
477 if (!skb->dst) {
478 printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
479 kfree_skb(skb);
480 return 1;
481 }
482
483 paddr = ((struct rtable*)skb->dst)->rt_gateway;
484
485 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev))
486 return 0;
487
488 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
489
490 if (n) {
491 n->used = jiffies;
492 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) {
493 read_lock_bh(&n->lock);
494 memcpy(haddr, n->ha, dev->addr_len);
495 read_unlock_bh(&n->lock);
496 neigh_release(n);
497 return 0;
498 }
499 neigh_release(n);
500 } else
501 kfree_skb(skb);
502 return 1;
503}
504
505/* END OF OBSOLETE FUNCTIONS */
506
507int arp_bind_neighbour(struct dst_entry *dst)
508{
509 struct net_device *dev = dst->dev;
510 struct neighbour *n = dst->neighbour;
511
512 if (dev == NULL)
513 return -EINVAL;
514 if (n == NULL) {
515 u32 nexthop = ((struct rtable*)dst)->rt_gateway;
516 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT))
517 nexthop = 0;
518 n = __neigh_lookup_errno(
519#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
520 dev->type == ARPHRD_ATM ? clip_tbl_hook :
521#endif
522 &arp_tbl, &nexthop, dev);
523 if (IS_ERR(n))
524 return PTR_ERR(n);
525 dst->neighbour = n;
526 }
527 return 0;
528}
529
530/*
531 * Check if we can use proxy ARP for this path
532 */
533
534static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
535{
536 struct in_device *out_dev;
537 int imi, omi = -1;
538
539 if (!IN_DEV_PROXY_ARP(in_dev))
540 return 0;
541
542 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0)
543 return 1;
544 if (imi == -1)
545 return 0;
546
547 /* place to check for proxy_arp for routes */
548
549 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) {
550 omi = IN_DEV_MEDIUM_ID(out_dev);
551 in_dev_put(out_dev);
552 }
553 return (omi != imi && omi != -1);
554}
555
556/*
557 * Interface to link layer: send routine and receive handler.
558 */
559
560/*
561 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
562 * message.
563 */
564struct sk_buff *arp_create(int type, int ptype, u32 dest_ip,
565 struct net_device *dev, u32 src_ip,
566 unsigned char *dest_hw, unsigned char *src_hw,
567 unsigned char *target_hw)
568{
569 struct sk_buff *skb;
570 struct arphdr *arp;
571 unsigned char *arp_ptr;
572
573 /*
574 * Allocate a buffer
575 */
576
577 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4)
578 + LL_RESERVED_SPACE(dev), GFP_ATOMIC);
579 if (skb == NULL)
580 return NULL;
581
582 skb_reserve(skb, LL_RESERVED_SPACE(dev));
583 skb->nh.raw = skb->data;
584 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4));
585 skb->dev = dev;
586 skb->protocol = htons(ETH_P_ARP);
587 if (src_hw == NULL)
588 src_hw = dev->dev_addr;
589 if (dest_hw == NULL)
590 dest_hw = dev->broadcast;
591
592 /*
593 * Fill the device header for the ARP frame
594 */
595 if (dev->hard_header &&
596 dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0)
597 goto out;
598
599 /*
600 * Fill out the arp protocol part.
601 *
602 * The arp hardware type should match the device type, except for FDDI,
603 * which (according to RFC 1390) should always equal 1 (Ethernet).
604 */
605 /*
606 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
607 * DIX code for the protocol. Make these device structure fields.
608 */
609 switch (dev->type) {
610 default:
611 arp->ar_hrd = htons(dev->type);
612 arp->ar_pro = htons(ETH_P_IP);
613 break;
614
615#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
616 case ARPHRD_AX25:
617 arp->ar_hrd = htons(ARPHRD_AX25);
618 arp->ar_pro = htons(AX25_P_IP);
619 break;
620
621#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
622 case ARPHRD_NETROM:
623 arp->ar_hrd = htons(ARPHRD_NETROM);
624 arp->ar_pro = htons(AX25_P_IP);
625 break;
626#endif
627#endif
628
629#ifdef CONFIG_FDDI
630 case ARPHRD_FDDI:
631 arp->ar_hrd = htons(ARPHRD_ETHER);
632 arp->ar_pro = htons(ETH_P_IP);
633 break;
634#endif
635#ifdef CONFIG_TR
636 case ARPHRD_IEEE802_TR:
637 arp->ar_hrd = htons(ARPHRD_IEEE802);
638 arp->ar_pro = htons(ETH_P_IP);
639 break;
640#endif
641 }
642
643 arp->ar_hln = dev->addr_len;
644 arp->ar_pln = 4;
645 arp->ar_op = htons(type);
646
647 arp_ptr=(unsigned char *)(arp+1);
648
649 memcpy(arp_ptr, src_hw, dev->addr_len);
650 arp_ptr+=dev->addr_len;
651 memcpy(arp_ptr, &src_ip,4);
652 arp_ptr+=4;
653 if (target_hw != NULL)
654 memcpy(arp_ptr, target_hw, dev->addr_len);
655 else
656 memset(arp_ptr, 0, dev->addr_len);
657 arp_ptr+=dev->addr_len;
658 memcpy(arp_ptr, &dest_ip, 4);
659
660 return skb;
661
662out:
663 kfree_skb(skb);
664 return NULL;
665}
666
667/*
668 * Send an arp packet.
669 */
670void arp_xmit(struct sk_buff *skb)
671{
672 /* Send it off, maybe filter it using firewalling first. */
673 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
674}
675
676/*
677 * Create and send an arp packet.
678 */
679void arp_send(int type, int ptype, u32 dest_ip,
680 struct net_device *dev, u32 src_ip,
681 unsigned char *dest_hw, unsigned char *src_hw,
682 unsigned char *target_hw)
683{
684 struct sk_buff *skb;
685
686 /*
687 * No arp on this interface.
688 */
689
690 if (dev->flags&IFF_NOARP)
691 return;
692
693 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
694 dest_hw, src_hw, target_hw);
695 if (skb == NULL) {
696 return;
697 }
698
699 arp_xmit(skb);
700}
701
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702/*
703 * Process an arp request.
704 */
705
706static int arp_process(struct sk_buff *skb)
707{
708 struct net_device *dev = skb->dev;
709 struct in_device *in_dev = in_dev_get(dev);
710 struct arphdr *arp;
711 unsigned char *arp_ptr;
712 struct rtable *rt;
713 unsigned char *sha, *tha;
714 u32 sip, tip;
715 u16 dev_type = dev->type;
716 int addr_type;
717 struct neighbour *n;
718
719 /* arp_rcv below verifies the ARP header and verifies the device
720 * is ARP'able.
721 */
722
723 if (in_dev == NULL)
724 goto out;
725
726 arp = skb->nh.arph;
727
728 switch (dev_type) {
729 default:
730 if (arp->ar_pro != htons(ETH_P_IP) ||
731 htons(dev_type) != arp->ar_hrd)
732 goto out;
733 break;
734#ifdef CONFIG_NET_ETHERNET
735 case ARPHRD_ETHER:
736#endif
737#ifdef CONFIG_TR
738 case ARPHRD_IEEE802_TR:
739#endif
740#ifdef CONFIG_FDDI
741 case ARPHRD_FDDI:
742#endif
743#ifdef CONFIG_NET_FC
744 case ARPHRD_IEEE802:
745#endif
746#if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_TR) || \
747 defined(CONFIG_FDDI) || defined(CONFIG_NET_FC)
748 /*
749 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
750 * devices, according to RFC 2625) devices will accept ARP
751 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
752 * This is the case also of FDDI, where the RFC 1390 says that
753 * FDDI devices should accept ARP hardware of (1) Ethernet,
754 * however, to be more robust, we'll accept both 1 (Ethernet)
755 * or 6 (IEEE 802.2)
756 */
757 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
758 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
759 arp->ar_pro != htons(ETH_P_IP))
760 goto out;
761 break;
762#endif
763#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
764 case ARPHRD_AX25:
765 if (arp->ar_pro != htons(AX25_P_IP) ||
766 arp->ar_hrd != htons(ARPHRD_AX25))
767 goto out;
768 break;
769#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
770 case ARPHRD_NETROM:
771 if (arp->ar_pro != htons(AX25_P_IP) ||
772 arp->ar_hrd != htons(ARPHRD_NETROM))
773 goto out;
774 break;
775#endif
776#endif
777 }
778
779 /* Understand only these message types */
780
781 if (arp->ar_op != htons(ARPOP_REPLY) &&
782 arp->ar_op != htons(ARPOP_REQUEST))
783 goto out;
784
785/*
786 * Extract fields
787 */
788 arp_ptr= (unsigned char *)(arp+1);
789 sha = arp_ptr;
790 arp_ptr += dev->addr_len;
791 memcpy(&sip, arp_ptr, 4);
792 arp_ptr += 4;
793 tha = arp_ptr;
794 arp_ptr += dev->addr_len;
795 memcpy(&tip, arp_ptr, 4);
796/*
797 * Check for bad requests for 127.x.x.x and requests for multicast
798 * addresses. If this is one such, delete it.
799 */
800 if (LOOPBACK(tip) || MULTICAST(tip))
801 goto out;
802
803/*
804 * Special case: We must set Frame Relay source Q.922 address
805 */
806 if (dev_type == ARPHRD_DLCI)
807 sha = dev->broadcast;
808
809/*
810 * Process entry. The idea here is we want to send a reply if it is a
811 * request for us or if it is a request for someone else that we hold
812 * a proxy for. We want to add an entry to our cache if it is a reply
813 * to us or if it is a request for our address.
814 * (The assumption for this last is that if someone is requesting our
815 * address, they are probably intending to talk to us, so it saves time
816 * if we cache their address. Their address is also probably not in
817 * our cache, since ours is not in their cache.)
818 *
819 * Putting this another way, we only care about replies if they are to
820 * us, in which case we add them to the cache. For requests, we care
821 * about those for us and those for our proxies. We reply to both,
822 * and in the case of requests for us we add the requester to the arp
823 * cache.
824 */
825
826 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
827 if (sip == 0) {
828 if (arp->ar_op == htons(ARPOP_REQUEST) &&
829 inet_addr_type(tip) == RTN_LOCAL &&
830 !arp_ignore(in_dev,dev,sip,tip))
831 arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr);
832 goto out;
833 }
834
835 if (arp->ar_op == htons(ARPOP_REQUEST) &&
836 ip_route_input(skb, tip, sip, 0, dev) == 0) {
837
838 rt = (struct rtable*)skb->dst;
839 addr_type = rt->rt_type;
840
841 if (addr_type == RTN_LOCAL) {
842 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
843 if (n) {
844 int dont_send = 0;
845
846 if (!dont_send)
847 dont_send |= arp_ignore(in_dev,dev,sip,tip);
848 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
849 dont_send |= arp_filter(sip,tip,dev);
850 if (!dont_send)
851 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
852
853 neigh_release(n);
854 }
855 goto out;
856 } else if (IN_DEV_FORWARD(in_dev)) {
857 if ((rt->rt_flags&RTCF_DNAT) ||
858 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev &&
859 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) {
860 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
861 if (n)
862 neigh_release(n);
863
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700864 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 skb->pkt_type == PACKET_HOST ||
866 in_dev->arp_parms->proxy_delay == 0) {
867 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
868 } else {
869 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb);
870 in_dev_put(in_dev);
871 return 0;
872 }
873 goto out;
874 }
875 }
876 }
877
878 /* Update our ARP tables */
879
880 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
881
Neil Hormanabd596a2006-03-20 22:39:47 -0800882 if (ipv4_devconf.arp_accept) {
883 /* Unsolicited ARP is not accepted by default.
884 It is possible, that this option should be enabled for some
885 devices (strip is candidate)
886 */
887 if (n == NULL &&
888 arp->ar_op == htons(ARPOP_REPLY) &&
889 inet_addr_type(sip) == RTN_UNICAST)
890 n = __neigh_lookup(&arp_tbl, &sip, dev, -1);
891 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892
893 if (n) {
894 int state = NUD_REACHABLE;
895 int override;
896
897 /* If several different ARP replies follows back-to-back,
898 use the FIRST one. It is possible, if several proxy
899 agents are active. Taking the first reply prevents
900 arp trashing and chooses the fastest router.
901 */
902 override = time_after(jiffies, n->updated + n->parms->locktime);
903
904 /* Broadcast replies and request packets
905 do not assert neighbour reachability.
906 */
907 if (arp->ar_op != htons(ARPOP_REPLY) ||
908 skb->pkt_type != PACKET_HOST)
909 state = NUD_STALE;
910 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0);
911 neigh_release(n);
912 }
913
914out:
915 if (in_dev)
916 in_dev_put(in_dev);
917 kfree_skb(skb);
918 return 0;
919}
920
Herbert Xu444fc8f2005-10-03 14:18:10 -0700921static void parp_redo(struct sk_buff *skb)
922{
923 arp_process(skb);
924}
925
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926
927/*
928 * Receive an arp request from the device layer.
929 */
930
David S. Millerf2ccd8f2005-08-09 19:34:12 -0700931int arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932{
933 struct arphdr *arp;
934
935 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
936 if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
937 (2 * dev->addr_len) +
938 (2 * sizeof(u32)))))
939 goto freeskb;
940
941 arp = skb->nh.arph;
942 if (arp->ar_hln != dev->addr_len ||
943 dev->flags & IFF_NOARP ||
944 skb->pkt_type == PACKET_OTHERHOST ||
945 skb->pkt_type == PACKET_LOOPBACK ||
946 arp->ar_pln != 4)
947 goto freeskb;
948
949 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
950 goto out_of_mem;
951
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700952 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
955
956freeskb:
957 kfree_skb(skb);
958out_of_mem:
959 return 0;
960}
961
962/*
963 * User level interface (ioctl)
964 */
965
966/*
967 * Set (create) an ARP cache entry.
968 */
969
970static int arp_req_set(struct arpreq *r, struct net_device * dev)
971{
972 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
973 struct neighbour *neigh;
974 int err;
975
976 if (r->arp_flags&ATF_PUBL) {
977 u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
978 if (mask && mask != 0xFFFFFFFF)
979 return -EINVAL;
980 if (!dev && (r->arp_flags & ATF_COM)) {
981 dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data);
982 if (!dev)
983 return -ENODEV;
984 }
985 if (mask) {
986 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL)
987 return -ENOBUFS;
988 return 0;
989 }
990 if (dev == NULL) {
991 ipv4_devconf.proxy_arp = 1;
992 return 0;
993 }
Herbert Xue5ed6392005-10-03 14:35:55 -0700994 if (__in_dev_get_rtnl(dev)) {
995 __in_dev_get_rtnl(dev)->cnf.proxy_arp = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 return 0;
997 }
998 return -ENXIO;
999 }
1000
1001 if (r->arp_flags & ATF_PERM)
1002 r->arp_flags |= ATF_COM;
1003 if (dev == NULL) {
1004 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
1005 .tos = RTO_ONLINK } } };
1006 struct rtable * rt;
1007 if ((err = ip_route_output_key(&rt, &fl)) != 0)
1008 return err;
1009 dev = rt->u.dst.dev;
1010 ip_rt_put(rt);
1011 if (!dev)
1012 return -EINVAL;
1013 }
1014 switch (dev->type) {
1015#ifdef CONFIG_FDDI
1016 case ARPHRD_FDDI:
1017 /*
1018 * According to RFC 1390, FDDI devices should accept ARP
1019 * hardware types of 1 (Ethernet). However, to be more
1020 * robust, we'll accept hardware types of either 1 (Ethernet)
1021 * or 6 (IEEE 802.2).
1022 */
1023 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1024 r->arp_ha.sa_family != ARPHRD_ETHER &&
1025 r->arp_ha.sa_family != ARPHRD_IEEE802)
1026 return -EINVAL;
1027 break;
1028#endif
1029 default:
1030 if (r->arp_ha.sa_family != dev->type)
1031 return -EINVAL;
1032 break;
1033 }
1034
1035 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1036 err = PTR_ERR(neigh);
1037 if (!IS_ERR(neigh)) {
1038 unsigned state = NUD_STALE;
1039 if (r->arp_flags & ATF_PERM)
1040 state = NUD_PERMANENT;
1041 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ?
1042 r->arp_ha.sa_data : NULL, state,
1043 NEIGH_UPDATE_F_OVERRIDE|
1044 NEIGH_UPDATE_F_ADMIN);
1045 neigh_release(neigh);
1046 }
1047 return err;
1048}
1049
1050static unsigned arp_state_to_flags(struct neighbour *neigh)
1051{
1052 unsigned flags = 0;
1053 if (neigh->nud_state&NUD_PERMANENT)
1054 flags = ATF_PERM|ATF_COM;
1055 else if (neigh->nud_state&NUD_VALID)
1056 flags = ATF_COM;
1057 return flags;
1058}
1059
1060/*
1061 * Get an ARP cache entry.
1062 */
1063
1064static int arp_req_get(struct arpreq *r, struct net_device *dev)
1065{
1066 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1067 struct neighbour *neigh;
1068 int err = -ENXIO;
1069
1070 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1071 if (neigh) {
1072 read_lock_bh(&neigh->lock);
1073 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1074 r->arp_flags = arp_state_to_flags(neigh);
1075 read_unlock_bh(&neigh->lock);
1076 r->arp_ha.sa_family = dev->type;
1077 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1078 neigh_release(neigh);
1079 err = 0;
1080 }
1081 return err;
1082}
1083
1084static int arp_req_delete(struct arpreq *r, struct net_device * dev)
1085{
1086 int err;
1087 u32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1088 struct neighbour *neigh;
1089
1090 if (r->arp_flags & ATF_PUBL) {
1091 u32 mask =
1092 ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1093 if (mask == 0xFFFFFFFF)
1094 return pneigh_delete(&arp_tbl, &ip, dev);
1095 if (mask == 0) {
1096 if (dev == NULL) {
1097 ipv4_devconf.proxy_arp = 0;
1098 return 0;
1099 }
Herbert Xue5ed6392005-10-03 14:35:55 -07001100 if (__in_dev_get_rtnl(dev)) {
1101 __in_dev_get_rtnl(dev)->cnf.proxy_arp = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 return 0;
1103 }
1104 return -ENXIO;
1105 }
1106 return -EINVAL;
1107 }
1108
1109 if (dev == NULL) {
1110 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
1111 .tos = RTO_ONLINK } } };
1112 struct rtable * rt;
1113 if ((err = ip_route_output_key(&rt, &fl)) != 0)
1114 return err;
1115 dev = rt->u.dst.dev;
1116 ip_rt_put(rt);
1117 if (!dev)
1118 return -EINVAL;
1119 }
1120 err = -ENXIO;
1121 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1122 if (neigh) {
1123 if (neigh->nud_state&~NUD_NOARP)
1124 err = neigh_update(neigh, NULL, NUD_FAILED,
1125 NEIGH_UPDATE_F_OVERRIDE|
1126 NEIGH_UPDATE_F_ADMIN);
1127 neigh_release(neigh);
1128 }
1129 return err;
1130}
1131
1132/*
1133 * Handle an ARP layer I/O control request.
1134 */
1135
1136int arp_ioctl(unsigned int cmd, void __user *arg)
1137{
1138 int err;
1139 struct arpreq r;
1140 struct net_device *dev = NULL;
1141
1142 switch (cmd) {
1143 case SIOCDARP:
1144 case SIOCSARP:
1145 if (!capable(CAP_NET_ADMIN))
1146 return -EPERM;
1147 case SIOCGARP:
1148 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1149 if (err)
1150 return -EFAULT;
1151 break;
1152 default:
1153 return -EINVAL;
1154 }
1155
1156 if (r.arp_pa.sa_family != AF_INET)
1157 return -EPFNOSUPPORT;
1158
1159 if (!(r.arp_flags & ATF_PUBL) &&
1160 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB)))
1161 return -EINVAL;
1162 if (!(r.arp_flags & ATF_NETMASK))
1163 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1164 htonl(0xFFFFFFFFUL);
1165 rtnl_lock();
1166 if (r.arp_dev[0]) {
1167 err = -ENODEV;
1168 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL)
1169 goto out;
1170
1171 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1172 if (!r.arp_ha.sa_family)
1173 r.arp_ha.sa_family = dev->type;
1174 err = -EINVAL;
1175 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1176 goto out;
1177 } else if (cmd == SIOCGARP) {
1178 err = -ENODEV;
1179 goto out;
1180 }
1181
1182 switch(cmd) {
1183 case SIOCDARP:
1184 err = arp_req_delete(&r, dev);
1185 break;
1186 case SIOCSARP:
1187 err = arp_req_set(&r, dev);
1188 break;
1189 case SIOCGARP:
1190 err = arp_req_get(&r, dev);
1191 if (!err && copy_to_user(arg, &r, sizeof(r)))
1192 err = -EFAULT;
1193 break;
1194 }
1195out:
1196 rtnl_unlock();
1197 return err;
1198}
1199
1200static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1201{
1202 struct net_device *dev = ptr;
1203
1204 switch (event) {
1205 case NETDEV_CHANGEADDR:
1206 neigh_changeaddr(&arp_tbl, dev);
1207 rt_cache_flush(0);
1208 break;
1209 default:
1210 break;
1211 }
1212
1213 return NOTIFY_DONE;
1214}
1215
1216static struct notifier_block arp_netdev_notifier = {
1217 .notifier_call = arp_netdev_event,
1218};
1219
1220/* Note, that it is not on notifier chain.
1221 It is necessary, that this routine was called after route cache will be
1222 flushed.
1223 */
1224void arp_ifdown(struct net_device *dev)
1225{
1226 neigh_ifdown(&arp_tbl, dev);
1227}
1228
1229
1230/*
1231 * Called once on startup.
1232 */
1233
1234static struct packet_type arp_packet_type = {
1235 .type = __constant_htons(ETH_P_ARP),
1236 .func = arp_rcv,
1237};
1238
1239static int arp_proc_init(void);
1240
1241void __init arp_init(void)
1242{
1243 neigh_table_init(&arp_tbl);
1244
1245 dev_add_pack(&arp_packet_type);
1246 arp_proc_init();
1247#ifdef CONFIG_SYSCTL
1248 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4,
1249 NET_IPV4_NEIGH, "ipv4", NULL, NULL);
1250#endif
1251 register_netdevice_notifier(&arp_netdev_notifier);
1252}
1253
1254#ifdef CONFIG_PROC_FS
1255#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1256
1257/* ------------------------------------------------------------------------ */
1258/*
1259 * ax25 -> ASCII conversion
1260 */
1261static char *ax2asc2(ax25_address *a, char *buf)
1262{
1263 char c, *s;
1264 int n;
1265
1266 for (n = 0, s = buf; n < 6; n++) {
1267 c = (a->ax25_call[n] >> 1) & 0x7F;
1268
1269 if (c != ' ') *s++ = c;
1270 }
1271
1272 *s++ = '-';
1273
1274 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
1275 *s++ = '1';
1276 n -= 10;
1277 }
1278
1279 *s++ = n + '0';
1280 *s++ = '\0';
1281
1282 if (*buf == '\0' || *buf == '-')
1283 return "*";
1284
1285 return buf;
1286
1287}
1288#endif /* CONFIG_AX25 */
1289
1290#define HBUFFERLEN 30
1291
1292static void arp_format_neigh_entry(struct seq_file *seq,
1293 struct neighbour *n)
1294{
1295 char hbuffer[HBUFFERLEN];
1296 const char hexbuf[] = "0123456789ABCDEF";
1297 int k, j;
1298 char tbuf[16];
1299 struct net_device *dev = n->dev;
1300 int hatype = dev->type;
1301
1302 read_lock(&n->lock);
1303 /* Convert hardware address to XX:XX:XX:XX ... form. */
1304#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1305 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1306 ax2asc2((ax25_address *)n->ha, hbuffer);
1307 else {
1308#endif
1309 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1310 hbuffer[k++] = hexbuf[(n->ha[j] >> 4) & 15];
1311 hbuffer[k++] = hexbuf[n->ha[j] & 15];
1312 hbuffer[k++] = ':';
1313 }
1314 hbuffer[--k] = 0;
1315#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1316 }
1317#endif
1318 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key));
1319 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1320 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1321 read_unlock(&n->lock);
1322}
1323
1324static void arp_format_pneigh_entry(struct seq_file *seq,
1325 struct pneigh_entry *n)
1326{
1327 struct net_device *dev = n->dev;
1328 int hatype = dev ? dev->type : 0;
1329 char tbuf[16];
1330
1331 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key));
1332 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1333 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1334 dev ? dev->name : "*");
1335}
1336
1337static int arp_seq_show(struct seq_file *seq, void *v)
1338{
1339 if (v == SEQ_START_TOKEN) {
1340 seq_puts(seq, "IP address HW type Flags "
1341 "HW address Mask Device\n");
1342 } else {
1343 struct neigh_seq_state *state = seq->private;
1344
1345 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1346 arp_format_pneigh_entry(seq, v);
1347 else
1348 arp_format_neigh_entry(seq, v);
1349 }
1350
1351 return 0;
1352}
1353
1354static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1355{
1356 /* Don't want to confuse "arp -a" w/ magic entries,
1357 * so we tell the generic iterator to skip NUD_NOARP.
1358 */
1359 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1360}
1361
1362/* ------------------------------------------------------------------------ */
1363
1364static struct seq_operations arp_seq_ops = {
1365 .start = arp_seq_start,
1366 .next = neigh_seq_next,
1367 .stop = neigh_seq_stop,
1368 .show = arp_seq_show,
1369};
1370
1371static int arp_seq_open(struct inode *inode, struct file *file)
1372{
1373 struct seq_file *seq;
1374 int rc = -ENOMEM;
1375 struct neigh_seq_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
1376
1377 if (!s)
1378 goto out;
1379
1380 memset(s, 0, sizeof(*s));
1381 rc = seq_open(file, &arp_seq_ops);
1382 if (rc)
1383 goto out_kfree;
1384
1385 seq = file->private_data;
1386 seq->private = s;
1387out:
1388 return rc;
1389out_kfree:
1390 kfree(s);
1391 goto out;
1392}
1393
1394static struct file_operations arp_seq_fops = {
1395 .owner = THIS_MODULE,
1396 .open = arp_seq_open,
1397 .read = seq_read,
1398 .llseek = seq_lseek,
1399 .release = seq_release_private,
1400};
1401
1402static int __init arp_proc_init(void)
1403{
1404 if (!proc_net_fops_create("arp", S_IRUGO, &arp_seq_fops))
1405 return -ENOMEM;
1406 return 0;
1407}
1408
1409#else /* CONFIG_PROC_FS */
1410
1411static int __init arp_proc_init(void)
1412{
1413 return 0;
1414}
1415
1416#endif /* CONFIG_PROC_FS */
1417
1418EXPORT_SYMBOL(arp_broken_ops);
1419EXPORT_SYMBOL(arp_find);
1420EXPORT_SYMBOL(arp_rcv);
1421EXPORT_SYMBOL(arp_create);
1422EXPORT_SYMBOL(arp_xmit);
1423EXPORT_SYMBOL(arp_send);
1424EXPORT_SYMBOL(arp_tbl);
1425
1426#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
1427EXPORT_SYMBOL(clip_tbl_hook);
1428#endif