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1/* linux/net/ipv4/arp.c
2 *
3 * Copyright (C) 1994 by Florian La Roche
4 *
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
8 * address).
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Fixes:
16 * Alan Cox : Removed the Ethernet assumptions in
17 * Florian's code
18 * Alan Cox : Fixed some small errors in the ARP
19 * logic
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
40 * Craig Schlenter : Don't modify permanent entry
41 * during arp_rcv.
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
44 * eg intelligent arp probing and
45 * generation
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
51 * Jonathan Layes : Added arpd support through kerneld
52 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
58 * Alan Cox : Took the AP1000 nasty FDDI hack and
59 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
61 * one in...
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
73 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
74 */
75
76#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
77
78#include <linux/module.h>
79#include <linux/types.h>
80#include <linux/string.h>
81#include <linux/kernel.h>
82#include <linux/capability.h>
83#include <linux/socket.h>
84#include <linux/sockios.h>
85#include <linux/errno.h>
86#include <linux/in.h>
87#include <linux/mm.h>
88#include <linux/inet.h>
89#include <linux/inetdevice.h>
90#include <linux/netdevice.h>
91#include <linux/etherdevice.h>
92#include <linux/fddidevice.h>
93#include <linux/if_arp.h>
94#include <linux/skbuff.h>
95#include <linux/proc_fs.h>
96#include <linux/seq_file.h>
97#include <linux/stat.h>
98#include <linux/init.h>
99#include <linux/net.h>
100#include <linux/rcupdate.h>
101#include <linux/slab.h>
102#ifdef CONFIG_SYSCTL
103#include <linux/sysctl.h>
104#endif
105
106#include <net/net_namespace.h>
107#include <net/ip.h>
108#include <net/icmp.h>
109#include <net/route.h>
110#include <net/protocol.h>
111#include <net/tcp.h>
112#include <net/sock.h>
113#include <net/arp.h>
114#include <net/ax25.h>
115#include <net/netrom.h>
116
117#include <linux/uaccess.h>
118
119#include <linux/netfilter_arp.h>
120
121/*
122 * Interface to generic neighbour cache.
123 */
124static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
125static int arp_constructor(struct neighbour *neigh);
126static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
127static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
128static void parp_redo(struct sk_buff *skb);
129
130static const struct neigh_ops arp_generic_ops = {
131 .family = AF_INET,
132 .solicit = arp_solicit,
133 .error_report = arp_error_report,
134 .output = neigh_resolve_output,
135 .connected_output = neigh_connected_output,
136};
137
138static const struct neigh_ops arp_hh_ops = {
139 .family = AF_INET,
140 .solicit = arp_solicit,
141 .error_report = arp_error_report,
142 .output = neigh_resolve_output,
143 .connected_output = neigh_resolve_output,
144};
145
146static const struct neigh_ops arp_direct_ops = {
147 .family = AF_INET,
148 .output = neigh_direct_output,
149 .connected_output = neigh_direct_output,
150};
151
152static const struct neigh_ops arp_broken_ops = {
153 .family = AF_INET,
154 .solicit = arp_solicit,
155 .error_report = arp_error_report,
156 .output = neigh_compat_output,
157 .connected_output = neigh_compat_output,
158};
159
160struct neigh_table arp_tbl = {
161 .family = AF_INET,
162 .key_len = 4,
163 .hash = arp_hash,
164 .constructor = arp_constructor,
165 .proxy_redo = parp_redo,
166 .id = "arp_cache",
167 .parms = {
168 .tbl = &arp_tbl,
169 .reachable_time = 30 * HZ,
170 .data = {
171 [NEIGH_VAR_MCAST_PROBES] = 3,
172 [NEIGH_VAR_UCAST_PROBES] = 3,
173 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
174 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
175 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
176 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
177 [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
178 [NEIGH_VAR_PROXY_QLEN] = 64,
179 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
180 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
181 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
182 },
183 },
184 .gc_interval = 30 * HZ,
185 .gc_thresh1 = 128,
186 .gc_thresh2 = 512,
187 .gc_thresh3 = 1024,
188};
189EXPORT_SYMBOL(arp_tbl);
190
191int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
192{
193 switch (dev->type) {
194 case ARPHRD_ETHER:
195 case ARPHRD_FDDI:
196 case ARPHRD_IEEE802:
197 ip_eth_mc_map(addr, haddr);
198 return 0;
199 case ARPHRD_INFINIBAND:
200 ip_ib_mc_map(addr, dev->broadcast, haddr);
201 return 0;
202 case ARPHRD_IPGRE:
203 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
204 return 0;
205 default:
206 if (dir) {
207 memcpy(haddr, dev->broadcast, dev->addr_len);
208 return 0;
209 }
210 }
211 return -EINVAL;
212}
213
214
215static u32 arp_hash(const void *pkey,
216 const struct net_device *dev,
217 __u32 *hash_rnd)
218{
219 return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd);
220}
221
222static int arp_constructor(struct neighbour *neigh)
223{
224 __be32 addr = *(__be32 *)neigh->primary_key;
225 struct net_device *dev = neigh->dev;
226 struct in_device *in_dev;
227 struct neigh_parms *parms;
228
229 rcu_read_lock();
230 in_dev = __in_dev_get_rcu(dev);
231 if (in_dev == NULL) {
232 rcu_read_unlock();
233 return -EINVAL;
234 }
235
236 neigh->type = inet_addr_type(dev_net(dev), addr);
237
238 parms = in_dev->arp_parms;
239 __neigh_parms_put(neigh->parms);
240 neigh->parms = neigh_parms_clone(parms);
241 rcu_read_unlock();
242
243 if (!dev->header_ops) {
244 neigh->nud_state = NUD_NOARP;
245 neigh->ops = &arp_direct_ops;
246 neigh->output = neigh_direct_output;
247 } else {
248 /* Good devices (checked by reading texts, but only Ethernet is
249 tested)
250
251 ARPHRD_ETHER: (ethernet, apfddi)
252 ARPHRD_FDDI: (fddi)
253 ARPHRD_IEEE802: (tr)
254 ARPHRD_METRICOM: (strip)
255 ARPHRD_ARCNET:
256 etc. etc. etc.
257
258 ARPHRD_IPDDP will also work, if author repairs it.
259 I did not it, because this driver does not work even
260 in old paradigm.
261 */
262
263#if 1
264 /* So... these "amateur" devices are hopeless.
265 The only thing, that I can say now:
266 It is very sad that we need to keep ugly obsolete
267 code to make them happy.
268
269 They should be moved to more reasonable state, now
270 they use rebuild_header INSTEAD OF hard_start_xmit!!!
271 Besides that, they are sort of out of date
272 (a lot of redundant clones/copies, useless in 2.1),
273 I wonder why people believe that they work.
274 */
275 switch (dev->type) {
276 default:
277 break;
278 case ARPHRD_ROSE:
279#if IS_ENABLED(CONFIG_AX25)
280 case ARPHRD_AX25:
281#if IS_ENABLED(CONFIG_NETROM)
282 case ARPHRD_NETROM:
283#endif
284 neigh->ops = &arp_broken_ops;
285 neigh->output = neigh->ops->output;
286 return 0;
287#else
288 break;
289#endif
290 }
291#endif
292 if (neigh->type == RTN_MULTICAST) {
293 neigh->nud_state = NUD_NOARP;
294 arp_mc_map(addr, neigh->ha, dev, 1);
295 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
296 neigh->nud_state = NUD_NOARP;
297 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
298 } else if (neigh->type == RTN_BROADCAST ||
299 (dev->flags & IFF_POINTOPOINT)) {
300 neigh->nud_state = NUD_NOARP;
301 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
302 }
303
304 if (dev->header_ops->cache)
305 neigh->ops = &arp_hh_ops;
306 else
307 neigh->ops = &arp_generic_ops;
308
309 if (neigh->nud_state & NUD_VALID)
310 neigh->output = neigh->ops->connected_output;
311 else
312 neigh->output = neigh->ops->output;
313 }
314 return 0;
315}
316
317static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
318{
319 dst_link_failure(skb);
320 kfree_skb(skb);
321}
322
323static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
324{
325 __be32 saddr = 0;
326 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
327 struct net_device *dev = neigh->dev;
328 __be32 target = *(__be32 *)neigh->primary_key;
329 int probes = atomic_read(&neigh->probes);
330 struct in_device *in_dev;
331
332 rcu_read_lock();
333 in_dev = __in_dev_get_rcu(dev);
334 if (!in_dev) {
335 rcu_read_unlock();
336 return;
337 }
338 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
339 default:
340 case 0: /* By default announce any local IP */
341 if (skb && inet_addr_type(dev_net(dev),
342 ip_hdr(skb)->saddr) == RTN_LOCAL)
343 saddr = ip_hdr(skb)->saddr;
344 break;
345 case 1: /* Restrict announcements of saddr in same subnet */
346 if (!skb)
347 break;
348 saddr = ip_hdr(skb)->saddr;
349 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) {
350 /* saddr should be known to target */
351 if (inet_addr_onlink(in_dev, target, saddr))
352 break;
353 }
354 saddr = 0;
355 break;
356 case 2: /* Avoid secondary IPs, get a primary/preferred one */
357 break;
358 }
359 rcu_read_unlock();
360
361 if (!saddr)
362 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
363
364 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
365 if (probes < 0) {
366 if (!(neigh->nud_state & NUD_VALID))
367 pr_debug("trying to ucast probe in NUD_INVALID\n");
368 neigh_ha_snapshot(dst_ha, neigh, dev);
369 dst_hw = dst_ha;
370 } else {
371 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
372 if (probes < 0) {
373 neigh_app_ns(neigh);
374 return;
375 }
376 }
377
378 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
379 dst_hw, dev->dev_addr, NULL);
380}
381
382static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
383{
384 struct net *net = dev_net(in_dev->dev);
385 int scope;
386
387 switch (IN_DEV_ARP_IGNORE(in_dev)) {
388 case 0: /* Reply, the tip is already validated */
389 return 0;
390 case 1: /* Reply only if tip is configured on the incoming interface */
391 sip = 0;
392 scope = RT_SCOPE_HOST;
393 break;
394 case 2: /*
395 * Reply only if tip is configured on the incoming interface
396 * and is in same subnet as sip
397 */
398 scope = RT_SCOPE_HOST;
399 break;
400 case 3: /* Do not reply for scope host addresses */
401 sip = 0;
402 scope = RT_SCOPE_LINK;
403 in_dev = NULL;
404 break;
405 case 4: /* Reserved */
406 case 5:
407 case 6:
408 case 7:
409 return 0;
410 case 8: /* Do not reply */
411 return 1;
412 default:
413 return 0;
414 }
415 return !inet_confirm_addr(net, in_dev, sip, tip, scope);
416}
417
418static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
419{
420 struct rtable *rt;
421 int flag = 0;
422 /*unsigned long now; */
423 struct net *net = dev_net(dev);
424
425 rt = ip_route_output(net, sip, tip, 0, 0);
426 if (IS_ERR(rt))
427 return 1;
428 if (rt->dst.dev != dev) {
429 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
430 flag = 1;
431 }
432 ip_rt_put(rt);
433 return flag;
434}
435
436/* OBSOLETE FUNCTIONS */
437
438/*
439 * Find an arp mapping in the cache. If not found, post a request.
440 *
441 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
442 * even if it exists. It is supposed that skb->dev was mangled
443 * by a virtual device (eql, shaper). Nobody but broken devices
444 * is allowed to use this function, it is scheduled to be removed. --ANK
445 */
446
447static int arp_set_predefined(int addr_hint, unsigned char *haddr,
448 __be32 paddr, struct net_device *dev)
449{
450 switch (addr_hint) {
451 case RTN_LOCAL:
452 pr_debug("arp called for own IP address\n");
453 memcpy(haddr, dev->dev_addr, dev->addr_len);
454 return 1;
455 case RTN_MULTICAST:
456 arp_mc_map(paddr, haddr, dev, 1);
457 return 1;
458 case RTN_BROADCAST:
459 memcpy(haddr, dev->broadcast, dev->addr_len);
460 return 1;
461 }
462 return 0;
463}
464
465
466int arp_find(unsigned char *haddr, struct sk_buff *skb)
467{
468 struct net_device *dev = skb->dev;
469 __be32 paddr;
470 struct neighbour *n;
471
472 if (!skb_dst(skb)) {
473 pr_debug("arp_find is called with dst==NULL\n");
474 kfree_skb(skb);
475 return 1;
476 }
477
478 paddr = rt_nexthop(skb_rtable(skb), ip_hdr(skb)->daddr);
479 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr,
480 paddr, dev))
481 return 0;
482
483 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
484
485 if (n) {
486 n->used = jiffies;
487 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) {
488 neigh_ha_snapshot(haddr, n, dev);
489 neigh_release(n);
490 return 0;
491 }
492 neigh_release(n);
493 } else
494 kfree_skb(skb);
495 return 1;
496}
497EXPORT_SYMBOL(arp_find);
498
499/* END OF OBSOLETE FUNCTIONS */
500
501/*
502 * Check if we can use proxy ARP for this path
503 */
504static inline int arp_fwd_proxy(struct in_device *in_dev,
505 struct net_device *dev, struct rtable *rt)
506{
507 struct in_device *out_dev;
508 int imi, omi = -1;
509
510 if (rt->dst.dev == dev)
511 return 0;
512
513 if (!IN_DEV_PROXY_ARP(in_dev))
514 return 0;
515 imi = IN_DEV_MEDIUM_ID(in_dev);
516 if (imi == 0)
517 return 1;
518 if (imi == -1)
519 return 0;
520
521 /* place to check for proxy_arp for routes */
522
523 out_dev = __in_dev_get_rcu(rt->dst.dev);
524 if (out_dev)
525 omi = IN_DEV_MEDIUM_ID(out_dev);
526
527 return omi != imi && omi != -1;
528}
529
530/*
531 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
532 *
533 * RFC3069 supports proxy arp replies back to the same interface. This
534 * is done to support (ethernet) switch features, like RFC 3069, where
535 * the individual ports are not allowed to communicate with each
536 * other, BUT they are allowed to talk to the upstream router. As
537 * described in RFC 3069, it is possible to allow these hosts to
538 * communicate through the upstream router, by proxy_arp'ing.
539 *
540 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
541 *
542 * This technology is known by different names:
543 * In RFC 3069 it is called VLAN Aggregation.
544 * Cisco and Allied Telesyn call it Private VLAN.
545 * Hewlett-Packard call it Source-Port filtering or port-isolation.
546 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
547 *
548 */
549static inline int arp_fwd_pvlan(struct in_device *in_dev,
550 struct net_device *dev, struct rtable *rt,
551 __be32 sip, __be32 tip)
552{
553 /* Private VLAN is only concerned about the same ethernet segment */
554 if (rt->dst.dev != dev)
555 return 0;
556
557 /* Don't reply on self probes (often done by windowz boxes)*/
558 if (sip == tip)
559 return 0;
560
561 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
562 return 1;
563 else
564 return 0;
565}
566
567/*
568 * Interface to link layer: send routine and receive handler.
569 */
570
571/*
572 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
573 * message.
574 */
575struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
576 struct net_device *dev, __be32 src_ip,
577 const unsigned char *dest_hw,
578 const unsigned char *src_hw,
579 const unsigned char *target_hw)
580{
581 struct sk_buff *skb;
582 struct arphdr *arp;
583 unsigned char *arp_ptr;
584 int hlen = LL_RESERVED_SPACE(dev);
585 int tlen = dev->needed_tailroom;
586
587 /*
588 * Allocate a buffer
589 */
590
591 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
592 if (skb == NULL)
593 return NULL;
594
595 skb_reserve(skb, hlen);
596 skb_reset_network_header(skb);
597 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
598 skb->dev = dev;
599 skb->protocol = htons(ETH_P_ARP);
600 if (src_hw == NULL)
601 src_hw = dev->dev_addr;
602 if (dest_hw == NULL)
603 dest_hw = dev->broadcast;
604
605 /*
606 * Fill the device header for the ARP frame
607 */
608 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
609 goto out;
610
611 /*
612 * Fill out the arp protocol part.
613 *
614 * The arp hardware type should match the device type, except for FDDI,
615 * which (according to RFC 1390) should always equal 1 (Ethernet).
616 */
617 /*
618 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
619 * DIX code for the protocol. Make these device structure fields.
620 */
621 switch (dev->type) {
622 default:
623 arp->ar_hrd = htons(dev->type);
624 arp->ar_pro = htons(ETH_P_IP);
625 break;
626
627#if IS_ENABLED(CONFIG_AX25)
628 case ARPHRD_AX25:
629 arp->ar_hrd = htons(ARPHRD_AX25);
630 arp->ar_pro = htons(AX25_P_IP);
631 break;
632
633#if IS_ENABLED(CONFIG_NETROM)
634 case ARPHRD_NETROM:
635 arp->ar_hrd = htons(ARPHRD_NETROM);
636 arp->ar_pro = htons(AX25_P_IP);
637 break;
638#endif
639#endif
640
641#if IS_ENABLED(CONFIG_FDDI)
642 case ARPHRD_FDDI:
643 arp->ar_hrd = htons(ARPHRD_ETHER);
644 arp->ar_pro = htons(ETH_P_IP);
645 break;
646#endif
647 }
648
649 arp->ar_hln = dev->addr_len;
650 arp->ar_pln = 4;
651 arp->ar_op = htons(type);
652
653 arp_ptr = (unsigned char *)(arp + 1);
654
655 memcpy(arp_ptr, src_hw, dev->addr_len);
656 arp_ptr += dev->addr_len;
657 memcpy(arp_ptr, &src_ip, 4);
658 arp_ptr += 4;
659
660 switch (dev->type) {
661#if IS_ENABLED(CONFIG_FIREWIRE_NET)
662 case ARPHRD_IEEE1394:
663 break;
664#endif
665 default:
666 if (target_hw != NULL)
667 memcpy(arp_ptr, target_hw, dev->addr_len);
668 else
669 memset(arp_ptr, 0, dev->addr_len);
670 arp_ptr += dev->addr_len;
671 }
672 memcpy(arp_ptr, &dest_ip, 4);
673
674 return skb;
675
676out:
677 kfree_skb(skb);
678 return NULL;
679}
680EXPORT_SYMBOL(arp_create);
681
682/*
683 * Send an arp packet.
684 */
685void arp_xmit(struct sk_buff *skb)
686{
687 /* Send it off, maybe filter it using firewalling first. */
688 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
689}
690EXPORT_SYMBOL(arp_xmit);
691
692/*
693 * Create and send an arp packet.
694 */
695void arp_send(int type, int ptype, __be32 dest_ip,
696 struct net_device *dev, __be32 src_ip,
697 const unsigned char *dest_hw, const unsigned char *src_hw,
698 const unsigned char *target_hw)
699{
700 struct sk_buff *skb;
701
702 /*
703 * No arp on this interface.
704 */
705
706 if (dev->flags&IFF_NOARP)
707 return;
708
709 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
710 dest_hw, src_hw, target_hw);
711 if (skb == NULL)
712 return;
713
714 arp_xmit(skb);
715}
716EXPORT_SYMBOL(arp_send);
717
718/*
719 * Process an arp request.
720 */
721
722static int arp_process(struct sk_buff *skb)
723{
724 struct net_device *dev = skb->dev;
725 struct in_device *in_dev = __in_dev_get_rcu(dev);
726 struct arphdr *arp;
727 unsigned char *arp_ptr;
728 struct rtable *rt;
729 unsigned char *sha;
730 __be32 sip, tip;
731 u16 dev_type = dev->type;
732 int addr_type;
733 struct neighbour *n;
734 struct net *net = dev_net(dev);
735 bool is_garp = false;
736
737 /* arp_rcv below verifies the ARP header and verifies the device
738 * is ARP'able.
739 */
740
741 if (in_dev == NULL)
742 goto out;
743
744 arp = arp_hdr(skb);
745
746 switch (dev_type) {
747 default:
748 if (arp->ar_pro != htons(ETH_P_IP) ||
749 htons(dev_type) != arp->ar_hrd)
750 goto out;
751 break;
752 case ARPHRD_ETHER:
753 case ARPHRD_FDDI:
754 case ARPHRD_IEEE802:
755 /*
756 * ETHERNET, and Fibre Channel (which are IEEE 802
757 * devices, according to RFC 2625) devices will accept ARP
758 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
759 * This is the case also of FDDI, where the RFC 1390 says that
760 * FDDI devices should accept ARP hardware of (1) Ethernet,
761 * however, to be more robust, we'll accept both 1 (Ethernet)
762 * or 6 (IEEE 802.2)
763 */
764 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
765 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
766 arp->ar_pro != htons(ETH_P_IP))
767 goto out;
768 break;
769 case ARPHRD_AX25:
770 if (arp->ar_pro != htons(AX25_P_IP) ||
771 arp->ar_hrd != htons(ARPHRD_AX25))
772 goto out;
773 break;
774 case ARPHRD_NETROM:
775 if (arp->ar_pro != htons(AX25_P_IP) ||
776 arp->ar_hrd != htons(ARPHRD_NETROM))
777 goto out;
778 break;
779 }
780
781 /* Understand only these message types */
782
783 if (arp->ar_op != htons(ARPOP_REPLY) &&
784 arp->ar_op != htons(ARPOP_REQUEST))
785 goto out;
786
787/*
788 * Extract fields
789 */
790 arp_ptr = (unsigned char *)(arp + 1);
791 sha = arp_ptr;
792 arp_ptr += dev->addr_len;
793 memcpy(&sip, arp_ptr, 4);
794 arp_ptr += 4;
795 switch (dev_type) {
796#if IS_ENABLED(CONFIG_FIREWIRE_NET)
797 case ARPHRD_IEEE1394:
798 break;
799#endif
800 default:
801 arp_ptr += dev->addr_len;
802 }
803 memcpy(&tip, arp_ptr, 4);
804/*
805 * Check for bad requests for 127.x.x.x and requests for multicast
806 * addresses. If this is one such, delete it.
807 */
808 if (ipv4_is_multicast(tip) ||
809 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
810 goto out;
811
812/*
813 * Special case: We must set Frame Relay source Q.922 address
814 */
815 if (dev_type == ARPHRD_DLCI)
816 sha = dev->broadcast;
817
818/*
819 * Process entry. The idea here is we want to send a reply if it is a
820 * request for us or if it is a request for someone else that we hold
821 * a proxy for. We want to add an entry to our cache if it is a reply
822 * to us or if it is a request for our address.
823 * (The assumption for this last is that if someone is requesting our
824 * address, they are probably intending to talk to us, so it saves time
825 * if we cache their address. Their address is also probably not in
826 * our cache, since ours is not in their cache.)
827 *
828 * Putting this another way, we only care about replies if they are to
829 * us, in which case we add them to the cache. For requests, we care
830 * about those for us and those for our proxies. We reply to both,
831 * and in the case of requests for us we add the requester to the arp
832 * cache.
833 */
834
835 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
836 if (sip == 0) {
837 if (arp->ar_op == htons(ARPOP_REQUEST) &&
838 inet_addr_type(net, tip) == RTN_LOCAL &&
839 !arp_ignore(in_dev, sip, tip))
840 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
841 dev->dev_addr, sha);
842 goto out;
843 }
844
845 if (arp->ar_op == htons(ARPOP_REQUEST) &&
846 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
847
848 rt = skb_rtable(skb);
849 addr_type = rt->rt_type;
850
851 if (addr_type == RTN_LOCAL) {
852 int dont_send;
853
854 dont_send = arp_ignore(in_dev, sip, tip);
855 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
856 dont_send = arp_filter(sip, tip, dev);
857 if (!dont_send) {
858 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
859 if (n) {
860 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
861 dev, tip, sha, dev->dev_addr,
862 sha);
863 neigh_release(n);
864 }
865 }
866 goto out;
867 } else if (IN_DEV_FORWARD(in_dev)) {
868 if (addr_type == RTN_UNICAST &&
869 (arp_fwd_proxy(in_dev, dev, rt) ||
870 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
871 (rt->dst.dev != dev &&
872 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
873 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
874 if (n)
875 neigh_release(n);
876
877 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
878 skb->pkt_type == PACKET_HOST ||
879 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
880 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
881 dev, tip, sha, dev->dev_addr,
882 sha);
883 } else {
884 pneigh_enqueue(&arp_tbl,
885 in_dev->arp_parms, skb);
886 return 0;
887 }
888 goto out;
889 }
890 }
891 }
892
893 /* Update our ARP tables */
894
895 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
896
897 if (IN_DEV_ARP_ACCEPT(in_dev)) {
898 /* Unsolicited ARP is not accepted by default.
899 It is possible, that this option should be enabled for some
900 devices (strip is candidate)
901 */
902 is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip &&
903 inet_addr_type(net, sip) == RTN_UNICAST;
904
905 if (n == NULL &&
906 ((arp->ar_op == htons(ARPOP_REPLY) &&
907 inet_addr_type(net, sip) == RTN_UNICAST) || is_garp))
908 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
909 }
910
911 if (n) {
912 int state = NUD_REACHABLE;
913 int override;
914
915 /* If several different ARP replies follows back-to-back,
916 use the FIRST one. It is possible, if several proxy
917 agents are active. Taking the first reply prevents
918 arp trashing and chooses the fastest router.
919 */
920 override = time_after(jiffies,
921 n->updated +
922 NEIGH_VAR(n->parms, LOCKTIME)) ||
923 is_garp;
924
925 /* Broadcast replies and request packets
926 do not assert neighbour reachability.
927 */
928 if (arp->ar_op != htons(ARPOP_REPLY) ||
929 skb->pkt_type != PACKET_HOST)
930 state = NUD_STALE;
931 neigh_update(n, sha, state,
932 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
933 neigh_release(n);
934 }
935
936out:
937 consume_skb(skb);
938 return 0;
939}
940
941static void parp_redo(struct sk_buff *skb)
942{
943 arp_process(skb);
944}
945
946
947/*
948 * Receive an arp request from the device layer.
949 */
950
951static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
952 struct packet_type *pt, struct net_device *orig_dev)
953{
954 const struct arphdr *arp;
955
956 if (dev->flags & IFF_NOARP ||
957 skb->pkt_type == PACKET_OTHERHOST ||
958 skb->pkt_type == PACKET_LOOPBACK)
959 goto freeskb;
960
961 skb = skb_share_check(skb, GFP_ATOMIC);
962 if (!skb)
963 goto out_of_mem;
964
965 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
966 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
967 goto freeskb;
968
969 arp = arp_hdr(skb);
970 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
971 goto freeskb;
972
973 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
974
975 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
976
977freeskb:
978 kfree_skb(skb);
979out_of_mem:
980 return 0;
981}
982
983/*
984 * User level interface (ioctl)
985 */
986
987/*
988 * Set (create) an ARP cache entry.
989 */
990
991static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
992{
993 if (dev == NULL) {
994 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
995 return 0;
996 }
997 if (__in_dev_get_rtnl(dev)) {
998 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
999 return 0;
1000 }
1001 return -ENXIO;
1002}
1003
1004static int arp_req_set_public(struct net *net, struct arpreq *r,
1005 struct net_device *dev)
1006{
1007 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1008 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1009
1010 if (mask && mask != htonl(0xFFFFFFFF))
1011 return -EINVAL;
1012 if (!dev && (r->arp_flags & ATF_COM)) {
1013 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1014 r->arp_ha.sa_data);
1015 if (!dev)
1016 return -ENODEV;
1017 }
1018 if (mask) {
1019 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL)
1020 return -ENOBUFS;
1021 return 0;
1022 }
1023
1024 return arp_req_set_proxy(net, dev, 1);
1025}
1026
1027static int arp_req_set(struct net *net, struct arpreq *r,
1028 struct net_device *dev)
1029{
1030 __be32 ip;
1031 struct neighbour *neigh;
1032 int err;
1033
1034 if (r->arp_flags & ATF_PUBL)
1035 return arp_req_set_public(net, r, dev);
1036
1037 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1038 if (r->arp_flags & ATF_PERM)
1039 r->arp_flags |= ATF_COM;
1040 if (dev == NULL) {
1041 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1042
1043 if (IS_ERR(rt))
1044 return PTR_ERR(rt);
1045 dev = rt->dst.dev;
1046 ip_rt_put(rt);
1047 if (!dev)
1048 return -EINVAL;
1049 }
1050 switch (dev->type) {
1051#if IS_ENABLED(CONFIG_FDDI)
1052 case ARPHRD_FDDI:
1053 /*
1054 * According to RFC 1390, FDDI devices should accept ARP
1055 * hardware types of 1 (Ethernet). However, to be more
1056 * robust, we'll accept hardware types of either 1 (Ethernet)
1057 * or 6 (IEEE 802.2).
1058 */
1059 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1060 r->arp_ha.sa_family != ARPHRD_ETHER &&
1061 r->arp_ha.sa_family != ARPHRD_IEEE802)
1062 return -EINVAL;
1063 break;
1064#endif
1065 default:
1066 if (r->arp_ha.sa_family != dev->type)
1067 return -EINVAL;
1068 break;
1069 }
1070
1071 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1072 err = PTR_ERR(neigh);
1073 if (!IS_ERR(neigh)) {
1074 unsigned int state = NUD_STALE;
1075 if (r->arp_flags & ATF_PERM)
1076 state = NUD_PERMANENT;
1077 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1078 r->arp_ha.sa_data : NULL, state,
1079 NEIGH_UPDATE_F_OVERRIDE |
1080 NEIGH_UPDATE_F_ADMIN);
1081 neigh_release(neigh);
1082 }
1083 return err;
1084}
1085
1086static unsigned int arp_state_to_flags(struct neighbour *neigh)
1087{
1088 if (neigh->nud_state&NUD_PERMANENT)
1089 return ATF_PERM | ATF_COM;
1090 else if (neigh->nud_state&NUD_VALID)
1091 return ATF_COM;
1092 else
1093 return 0;
1094}
1095
1096/*
1097 * Get an ARP cache entry.
1098 */
1099
1100static int arp_req_get(struct arpreq *r, struct net_device *dev)
1101{
1102 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1103 struct neighbour *neigh;
1104 int err = -ENXIO;
1105
1106 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1107 if (neigh) {
1108 read_lock_bh(&neigh->lock);
1109 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1110 r->arp_flags = arp_state_to_flags(neigh);
1111 read_unlock_bh(&neigh->lock);
1112 r->arp_ha.sa_family = dev->type;
1113 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1114 neigh_release(neigh);
1115 err = 0;
1116 }
1117 return err;
1118}
1119
1120static int arp_invalidate(struct net_device *dev, __be32 ip)
1121{
1122 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1123 int err = -ENXIO;
1124
1125 if (neigh) {
1126 if (neigh->nud_state & ~NUD_NOARP)
1127 err = neigh_update(neigh, NULL, NUD_FAILED,
1128 NEIGH_UPDATE_F_OVERRIDE|
1129 NEIGH_UPDATE_F_ADMIN);
1130 neigh_release(neigh);
1131 }
1132
1133 return err;
1134}
1135
1136static int arp_req_delete_public(struct net *net, struct arpreq *r,
1137 struct net_device *dev)
1138{
1139 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1140 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1141
1142 if (mask == htonl(0xFFFFFFFF))
1143 return pneigh_delete(&arp_tbl, net, &ip, dev);
1144
1145 if (mask)
1146 return -EINVAL;
1147
1148 return arp_req_set_proxy(net, dev, 0);
1149}
1150
1151static int arp_req_delete(struct net *net, struct arpreq *r,
1152 struct net_device *dev)
1153{
1154 __be32 ip;
1155
1156 if (r->arp_flags & ATF_PUBL)
1157 return arp_req_delete_public(net, r, dev);
1158
1159 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1160 if (dev == NULL) {
1161 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1162 if (IS_ERR(rt))
1163 return PTR_ERR(rt);
1164 dev = rt->dst.dev;
1165 ip_rt_put(rt);
1166 if (!dev)
1167 return -EINVAL;
1168 }
1169 return arp_invalidate(dev, ip);
1170}
1171
1172/*
1173 * Handle an ARP layer I/O control request.
1174 */
1175
1176int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1177{
1178 int err;
1179 struct arpreq r;
1180 struct net_device *dev = NULL;
1181
1182 switch (cmd) {
1183 case SIOCDARP:
1184 case SIOCSARP:
1185 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1186 return -EPERM;
1187 case SIOCGARP:
1188 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1189 if (err)
1190 return -EFAULT;
1191 break;
1192 default:
1193 return -EINVAL;
1194 }
1195
1196 if (r.arp_pa.sa_family != AF_INET)
1197 return -EPFNOSUPPORT;
1198
1199 if (!(r.arp_flags & ATF_PUBL) &&
1200 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1201 return -EINVAL;
1202 if (!(r.arp_flags & ATF_NETMASK))
1203 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1204 htonl(0xFFFFFFFFUL);
1205 rtnl_lock();
1206 if (r.arp_dev[0]) {
1207 err = -ENODEV;
1208 dev = __dev_get_by_name(net, r.arp_dev);
1209 if (dev == NULL)
1210 goto out;
1211
1212 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1213 if (!r.arp_ha.sa_family)
1214 r.arp_ha.sa_family = dev->type;
1215 err = -EINVAL;
1216 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1217 goto out;
1218 } else if (cmd == SIOCGARP) {
1219 err = -ENODEV;
1220 goto out;
1221 }
1222
1223 switch (cmd) {
1224 case SIOCDARP:
1225 err = arp_req_delete(net, &r, dev);
1226 break;
1227 case SIOCSARP:
1228 err = arp_req_set(net, &r, dev);
1229 break;
1230 case SIOCGARP:
1231 err = arp_req_get(&r, dev);
1232 break;
1233 }
1234out:
1235 rtnl_unlock();
1236 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1237 err = -EFAULT;
1238 return err;
1239}
1240
1241static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1242 void *ptr)
1243{
1244 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1245 struct netdev_notifier_change_info *change_info;
1246
1247 switch (event) {
1248 case NETDEV_CHANGEADDR:
1249 neigh_changeaddr(&arp_tbl, dev);
1250 rt_cache_flush(dev_net(dev));
1251 break;
1252 case NETDEV_CHANGE:
1253 change_info = ptr;
1254 if (change_info->flags_changed & IFF_NOARP)
1255 neigh_changeaddr(&arp_tbl, dev);
1256 break;
1257 default:
1258 break;
1259 }
1260
1261 return NOTIFY_DONE;
1262}
1263
1264static struct notifier_block arp_netdev_notifier = {
1265 .notifier_call = arp_netdev_event,
1266};
1267
1268/* Note, that it is not on notifier chain.
1269 It is necessary, that this routine was called after route cache will be
1270 flushed.
1271 */
1272void arp_ifdown(struct net_device *dev)
1273{
1274 neigh_ifdown(&arp_tbl, dev);
1275}
1276
1277
1278/*
1279 * Called once on startup.
1280 */
1281
1282static struct packet_type arp_packet_type __read_mostly = {
1283 .type = cpu_to_be16(ETH_P_ARP),
1284 .func = arp_rcv,
1285};
1286
1287static int arp_proc_init(void);
1288
1289void __init arp_init(void)
1290{
1291 neigh_table_init(&arp_tbl);
1292
1293 dev_add_pack(&arp_packet_type);
1294 arp_proc_init();
1295#ifdef CONFIG_SYSCTL
1296 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1297#endif
1298 register_netdevice_notifier(&arp_netdev_notifier);
1299}
1300
1301#ifdef CONFIG_PROC_FS
1302#if IS_ENABLED(CONFIG_AX25)
1303
1304/* ------------------------------------------------------------------------ */
1305/*
1306 * ax25 -> ASCII conversion
1307 */
1308static char *ax2asc2(ax25_address *a, char *buf)
1309{
1310 char c, *s;
1311 int n;
1312
1313 for (n = 0, s = buf; n < 6; n++) {
1314 c = (a->ax25_call[n] >> 1) & 0x7F;
1315
1316 if (c != ' ')
1317 *s++ = c;
1318 }
1319
1320 *s++ = '-';
1321 n = (a->ax25_call[6] >> 1) & 0x0F;
1322 if (n > 9) {
1323 *s++ = '1';
1324 n -= 10;
1325 }
1326
1327 *s++ = n + '0';
1328 *s++ = '\0';
1329
1330 if (*buf == '\0' || *buf == '-')
1331 return "*";
1332
1333 return buf;
1334}
1335#endif /* CONFIG_AX25 */
1336
1337#define HBUFFERLEN 30
1338
1339static void arp_format_neigh_entry(struct seq_file *seq,
1340 struct neighbour *n)
1341{
1342 char hbuffer[HBUFFERLEN];
1343 int k, j;
1344 char tbuf[16];
1345 struct net_device *dev = n->dev;
1346 int hatype = dev->type;
1347
1348 read_lock(&n->lock);
1349 /* Convert hardware address to XX:XX:XX:XX ... form. */
1350#if IS_ENABLED(CONFIG_AX25)
1351 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1352 ax2asc2((ax25_address *)n->ha, hbuffer);
1353 else {
1354#endif
1355 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1356 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1357 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1358 hbuffer[k++] = ':';
1359 }
1360 if (k != 0)
1361 --k;
1362 hbuffer[k] = 0;
1363#if IS_ENABLED(CONFIG_AX25)
1364 }
1365#endif
1366 sprintf(tbuf, "%pI4", n->primary_key);
1367 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1368 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1369 read_unlock(&n->lock);
1370}
1371
1372static void arp_format_pneigh_entry(struct seq_file *seq,
1373 struct pneigh_entry *n)
1374{
1375 struct net_device *dev = n->dev;
1376 int hatype = dev ? dev->type : 0;
1377 char tbuf[16];
1378
1379 sprintf(tbuf, "%pI4", n->key);
1380 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1381 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1382 dev ? dev->name : "*");
1383}
1384
1385static int arp_seq_show(struct seq_file *seq, void *v)
1386{
1387 if (v == SEQ_START_TOKEN) {
1388 seq_puts(seq, "IP address HW type Flags "
1389 "HW address Mask Device\n");
1390 } else {
1391 struct neigh_seq_state *state = seq->private;
1392
1393 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1394 arp_format_pneigh_entry(seq, v);
1395 else
1396 arp_format_neigh_entry(seq, v);
1397 }
1398
1399 return 0;
1400}
1401
1402static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1403{
1404 /* Don't want to confuse "arp -a" w/ magic entries,
1405 * so we tell the generic iterator to skip NUD_NOARP.
1406 */
1407 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1408}
1409
1410/* ------------------------------------------------------------------------ */
1411
1412static const struct seq_operations arp_seq_ops = {
1413 .start = arp_seq_start,
1414 .next = neigh_seq_next,
1415 .stop = neigh_seq_stop,
1416 .show = arp_seq_show,
1417};
1418
1419static int arp_seq_open(struct inode *inode, struct file *file)
1420{
1421 return seq_open_net(inode, file, &arp_seq_ops,
1422 sizeof(struct neigh_seq_state));
1423}
1424
1425static const struct file_operations arp_seq_fops = {
1426 .owner = THIS_MODULE,
1427 .open = arp_seq_open,
1428 .read = seq_read,
1429 .llseek = seq_lseek,
1430 .release = seq_release_net,
1431};
1432
1433
1434static int __net_init arp_net_init(struct net *net)
1435{
1436 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops))
1437 return -ENOMEM;
1438 return 0;
1439}
1440
1441static void __net_exit arp_net_exit(struct net *net)
1442{
1443 remove_proc_entry("arp", net->proc_net);
1444}
1445
1446static struct pernet_operations arp_net_ops = {
1447 .init = arp_net_init,
1448 .exit = arp_net_exit,
1449};
1450
1451static int __init arp_proc_init(void)
1452{
1453 return register_pernet_subsys(&arp_net_ops);
1454}
1455
1456#else /* CONFIG_PROC_FS */
1457
1458static int __init arp_proc_init(void)
1459{
1460 return 0;
1461}
1462
1463#endif /* CONFIG_PROC_FS */
1/* linux/net/ipv4/arp.c
2 *
3 * Copyright (C) 1994 by Florian La Roche
4 *
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
8 * address).
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Fixes:
16 * Alan Cox : Removed the Ethernet assumptions in
17 * Florian's code
18 * Alan Cox : Fixed some small errors in the ARP
19 * logic
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
40 * Craig Schlenter : Don't modify permanent entry
41 * during arp_rcv.
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
44 * eg intelligent arp probing and
45 * generation
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
51 * Jonathan Layes : Added arpd support through kerneld
52 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
58 * Alan Cox : Took the AP1000 nasty FDDI hack and
59 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
61 * one in...
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
73 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
74 */
75
76#include <linux/module.h>
77#include <linux/types.h>
78#include <linux/string.h>
79#include <linux/kernel.h>
80#include <linux/capability.h>
81#include <linux/socket.h>
82#include <linux/sockios.h>
83#include <linux/errno.h>
84#include <linux/in.h>
85#include <linux/mm.h>
86#include <linux/inet.h>
87#include <linux/inetdevice.h>
88#include <linux/netdevice.h>
89#include <linux/etherdevice.h>
90#include <linux/fddidevice.h>
91#include <linux/if_arp.h>
92#include <linux/trdevice.h>
93#include <linux/skbuff.h>
94#include <linux/proc_fs.h>
95#include <linux/seq_file.h>
96#include <linux/stat.h>
97#include <linux/init.h>
98#include <linux/net.h>
99#include <linux/rcupdate.h>
100#include <linux/slab.h>
101#ifdef CONFIG_SYSCTL
102#include <linux/sysctl.h>
103#endif
104
105#include <net/net_namespace.h>
106#include <net/ip.h>
107#include <net/icmp.h>
108#include <net/route.h>
109#include <net/protocol.h>
110#include <net/tcp.h>
111#include <net/sock.h>
112#include <net/arp.h>
113#include <net/ax25.h>
114#include <net/netrom.h>
115#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
116#include <net/atmclip.h>
117struct neigh_table *clip_tbl_hook;
118EXPORT_SYMBOL(clip_tbl_hook);
119#endif
120
121#include <asm/system.h>
122#include <linux/uaccess.h>
123
124#include <linux/netfilter_arp.h>
125
126/*
127 * Interface to generic neighbour cache.
128 */
129static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 rnd);
130static int arp_constructor(struct neighbour *neigh);
131static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
132static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
133static void parp_redo(struct sk_buff *skb);
134
135static const struct neigh_ops arp_generic_ops = {
136 .family = AF_INET,
137 .solicit = arp_solicit,
138 .error_report = arp_error_report,
139 .output = neigh_resolve_output,
140 .connected_output = neigh_connected_output,
141};
142
143static const struct neigh_ops arp_hh_ops = {
144 .family = AF_INET,
145 .solicit = arp_solicit,
146 .error_report = arp_error_report,
147 .output = neigh_resolve_output,
148 .connected_output = neigh_resolve_output,
149};
150
151static const struct neigh_ops arp_direct_ops = {
152 .family = AF_INET,
153 .output = neigh_direct_output,
154 .connected_output = neigh_direct_output,
155};
156
157static const struct neigh_ops arp_broken_ops = {
158 .family = AF_INET,
159 .solicit = arp_solicit,
160 .error_report = arp_error_report,
161 .output = neigh_compat_output,
162 .connected_output = neigh_compat_output,
163};
164
165struct neigh_table arp_tbl = {
166 .family = AF_INET,
167 .entry_size = sizeof(struct neighbour) + 4,
168 .key_len = 4,
169 .hash = arp_hash,
170 .constructor = arp_constructor,
171 .proxy_redo = parp_redo,
172 .id = "arp_cache",
173 .parms = {
174 .tbl = &arp_tbl,
175 .base_reachable_time = 30 * HZ,
176 .retrans_time = 1 * HZ,
177 .gc_staletime = 60 * HZ,
178 .reachable_time = 30 * HZ,
179 .delay_probe_time = 5 * HZ,
180 .queue_len = 3,
181 .ucast_probes = 3,
182 .mcast_probes = 3,
183 .anycast_delay = 1 * HZ,
184 .proxy_delay = (8 * HZ) / 10,
185 .proxy_qlen = 64,
186 .locktime = 1 * HZ,
187 },
188 .gc_interval = 30 * HZ,
189 .gc_thresh1 = 128,
190 .gc_thresh2 = 512,
191 .gc_thresh3 = 1024,
192};
193EXPORT_SYMBOL(arp_tbl);
194
195int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
196{
197 switch (dev->type) {
198 case ARPHRD_ETHER:
199 case ARPHRD_FDDI:
200 case ARPHRD_IEEE802:
201 ip_eth_mc_map(addr, haddr);
202 return 0;
203 case ARPHRD_IEEE802_TR:
204 ip_tr_mc_map(addr, haddr);
205 return 0;
206 case ARPHRD_INFINIBAND:
207 ip_ib_mc_map(addr, dev->broadcast, haddr);
208 return 0;
209 case ARPHRD_IPGRE:
210 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
211 return 0;
212 default:
213 if (dir) {
214 memcpy(haddr, dev->broadcast, dev->addr_len);
215 return 0;
216 }
217 }
218 return -EINVAL;
219}
220
221
222static u32 arp_hash(const void *pkey,
223 const struct net_device *dev,
224 __u32 hash_rnd)
225{
226 return arp_hashfn(*(u32 *)pkey, dev, hash_rnd);
227}
228
229static int arp_constructor(struct neighbour *neigh)
230{
231 __be32 addr = *(__be32 *)neigh->primary_key;
232 struct net_device *dev = neigh->dev;
233 struct in_device *in_dev;
234 struct neigh_parms *parms;
235
236 rcu_read_lock();
237 in_dev = __in_dev_get_rcu(dev);
238 if (in_dev == NULL) {
239 rcu_read_unlock();
240 return -EINVAL;
241 }
242
243 neigh->type = inet_addr_type(dev_net(dev), addr);
244
245 parms = in_dev->arp_parms;
246 __neigh_parms_put(neigh->parms);
247 neigh->parms = neigh_parms_clone(parms);
248 rcu_read_unlock();
249
250 if (!dev->header_ops) {
251 neigh->nud_state = NUD_NOARP;
252 neigh->ops = &arp_direct_ops;
253 neigh->output = neigh_direct_output;
254 } else {
255 /* Good devices (checked by reading texts, but only Ethernet is
256 tested)
257
258 ARPHRD_ETHER: (ethernet, apfddi)
259 ARPHRD_FDDI: (fddi)
260 ARPHRD_IEEE802: (tr)
261 ARPHRD_METRICOM: (strip)
262 ARPHRD_ARCNET:
263 etc. etc. etc.
264
265 ARPHRD_IPDDP will also work, if author repairs it.
266 I did not it, because this driver does not work even
267 in old paradigm.
268 */
269
270#if 1
271 /* So... these "amateur" devices are hopeless.
272 The only thing, that I can say now:
273 It is very sad that we need to keep ugly obsolete
274 code to make them happy.
275
276 They should be moved to more reasonable state, now
277 they use rebuild_header INSTEAD OF hard_start_xmit!!!
278 Besides that, they are sort of out of date
279 (a lot of redundant clones/copies, useless in 2.1),
280 I wonder why people believe that they work.
281 */
282 switch (dev->type) {
283 default:
284 break;
285 case ARPHRD_ROSE:
286#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
287 case ARPHRD_AX25:
288#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
289 case ARPHRD_NETROM:
290#endif
291 neigh->ops = &arp_broken_ops;
292 neigh->output = neigh->ops->output;
293 return 0;
294#else
295 break;
296#endif
297 }
298#endif
299 if (neigh->type == RTN_MULTICAST) {
300 neigh->nud_state = NUD_NOARP;
301 arp_mc_map(addr, neigh->ha, dev, 1);
302 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
303 neigh->nud_state = NUD_NOARP;
304 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
305 } else if (neigh->type == RTN_BROADCAST ||
306 (dev->flags & IFF_POINTOPOINT)) {
307 neigh->nud_state = NUD_NOARP;
308 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
309 }
310
311 if (dev->header_ops->cache)
312 neigh->ops = &arp_hh_ops;
313 else
314 neigh->ops = &arp_generic_ops;
315
316 if (neigh->nud_state & NUD_VALID)
317 neigh->output = neigh->ops->connected_output;
318 else
319 neigh->output = neigh->ops->output;
320 }
321 return 0;
322}
323
324static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
325{
326 dst_link_failure(skb);
327 kfree_skb(skb);
328}
329
330static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
331{
332 __be32 saddr = 0;
333 u8 *dst_ha = NULL;
334 struct net_device *dev = neigh->dev;
335 __be32 target = *(__be32 *)neigh->primary_key;
336 int probes = atomic_read(&neigh->probes);
337 struct in_device *in_dev;
338
339 rcu_read_lock();
340 in_dev = __in_dev_get_rcu(dev);
341 if (!in_dev) {
342 rcu_read_unlock();
343 return;
344 }
345 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
346 default:
347 case 0: /* By default announce any local IP */
348 if (skb && inet_addr_type(dev_net(dev),
349 ip_hdr(skb)->saddr) == RTN_LOCAL)
350 saddr = ip_hdr(skb)->saddr;
351 break;
352 case 1: /* Restrict announcements of saddr in same subnet */
353 if (!skb)
354 break;
355 saddr = ip_hdr(skb)->saddr;
356 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) {
357 /* saddr should be known to target */
358 if (inet_addr_onlink(in_dev, target, saddr))
359 break;
360 }
361 saddr = 0;
362 break;
363 case 2: /* Avoid secondary IPs, get a primary/preferred one */
364 break;
365 }
366 rcu_read_unlock();
367
368 if (!saddr)
369 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
370
371 probes -= neigh->parms->ucast_probes;
372 if (probes < 0) {
373 if (!(neigh->nud_state & NUD_VALID))
374 printk(KERN_DEBUG
375 "trying to ucast probe in NUD_INVALID\n");
376 dst_ha = neigh->ha;
377 read_lock_bh(&neigh->lock);
378 } else {
379 probes -= neigh->parms->app_probes;
380 if (probes < 0) {
381#ifdef CONFIG_ARPD
382 neigh_app_ns(neigh);
383#endif
384 return;
385 }
386 }
387
388 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
389 dst_ha, dev->dev_addr, NULL);
390 if (dst_ha)
391 read_unlock_bh(&neigh->lock);
392}
393
394static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
395{
396 int scope;
397
398 switch (IN_DEV_ARP_IGNORE(in_dev)) {
399 case 0: /* Reply, the tip is already validated */
400 return 0;
401 case 1: /* Reply only if tip is configured on the incoming interface */
402 sip = 0;
403 scope = RT_SCOPE_HOST;
404 break;
405 case 2: /*
406 * Reply only if tip is configured on the incoming interface
407 * and is in same subnet as sip
408 */
409 scope = RT_SCOPE_HOST;
410 break;
411 case 3: /* Do not reply for scope host addresses */
412 sip = 0;
413 scope = RT_SCOPE_LINK;
414 break;
415 case 4: /* Reserved */
416 case 5:
417 case 6:
418 case 7:
419 return 0;
420 case 8: /* Do not reply */
421 return 1;
422 default:
423 return 0;
424 }
425 return !inet_confirm_addr(in_dev, sip, tip, scope);
426}
427
428static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
429{
430 struct rtable *rt;
431 int flag = 0;
432 /*unsigned long now; */
433 struct net *net = dev_net(dev);
434
435 rt = ip_route_output(net, sip, tip, 0, 0);
436 if (IS_ERR(rt))
437 return 1;
438 if (rt->dst.dev != dev) {
439 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
440 flag = 1;
441 }
442 ip_rt_put(rt);
443 return flag;
444}
445
446/* OBSOLETE FUNCTIONS */
447
448/*
449 * Find an arp mapping in the cache. If not found, post a request.
450 *
451 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
452 * even if it exists. It is supposed that skb->dev was mangled
453 * by a virtual device (eql, shaper). Nobody but broken devices
454 * is allowed to use this function, it is scheduled to be removed. --ANK
455 */
456
457static int arp_set_predefined(int addr_hint, unsigned char *haddr,
458 __be32 paddr, struct net_device *dev)
459{
460 switch (addr_hint) {
461 case RTN_LOCAL:
462 printk(KERN_DEBUG "ARP: arp called for own IP address\n");
463 memcpy(haddr, dev->dev_addr, dev->addr_len);
464 return 1;
465 case RTN_MULTICAST:
466 arp_mc_map(paddr, haddr, dev, 1);
467 return 1;
468 case RTN_BROADCAST:
469 memcpy(haddr, dev->broadcast, dev->addr_len);
470 return 1;
471 }
472 return 0;
473}
474
475
476int arp_find(unsigned char *haddr, struct sk_buff *skb)
477{
478 struct net_device *dev = skb->dev;
479 __be32 paddr;
480 struct neighbour *n;
481
482 if (!skb_dst(skb)) {
483 printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
484 kfree_skb(skb);
485 return 1;
486 }
487
488 paddr = skb_rtable(skb)->rt_gateway;
489
490 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr,
491 paddr, dev))
492 return 0;
493
494 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
495
496 if (n) {
497 n->used = jiffies;
498 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) {
499 neigh_ha_snapshot(haddr, n, dev);
500 neigh_release(n);
501 return 0;
502 }
503 neigh_release(n);
504 } else
505 kfree_skb(skb);
506 return 1;
507}
508EXPORT_SYMBOL(arp_find);
509
510/* END OF OBSOLETE FUNCTIONS */
511
512/*
513 * Check if we can use proxy ARP for this path
514 */
515static inline int arp_fwd_proxy(struct in_device *in_dev,
516 struct net_device *dev, struct rtable *rt)
517{
518 struct in_device *out_dev;
519 int imi, omi = -1;
520
521 if (rt->dst.dev == dev)
522 return 0;
523
524 if (!IN_DEV_PROXY_ARP(in_dev))
525 return 0;
526 imi = IN_DEV_MEDIUM_ID(in_dev);
527 if (imi == 0)
528 return 1;
529 if (imi == -1)
530 return 0;
531
532 /* place to check for proxy_arp for routes */
533
534 out_dev = __in_dev_get_rcu(rt->dst.dev);
535 if (out_dev)
536 omi = IN_DEV_MEDIUM_ID(out_dev);
537
538 return omi != imi && omi != -1;
539}
540
541/*
542 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
543 *
544 * RFC3069 supports proxy arp replies back to the same interface. This
545 * is done to support (ethernet) switch features, like RFC 3069, where
546 * the individual ports are not allowed to communicate with each
547 * other, BUT they are allowed to talk to the upstream router. As
548 * described in RFC 3069, it is possible to allow these hosts to
549 * communicate through the upstream router, by proxy_arp'ing.
550 *
551 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
552 *
553 * This technology is known by different names:
554 * In RFC 3069 it is called VLAN Aggregation.
555 * Cisco and Allied Telesyn call it Private VLAN.
556 * Hewlett-Packard call it Source-Port filtering or port-isolation.
557 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
558 *
559 */
560static inline int arp_fwd_pvlan(struct in_device *in_dev,
561 struct net_device *dev, struct rtable *rt,
562 __be32 sip, __be32 tip)
563{
564 /* Private VLAN is only concerned about the same ethernet segment */
565 if (rt->dst.dev != dev)
566 return 0;
567
568 /* Don't reply on self probes (often done by windowz boxes)*/
569 if (sip == tip)
570 return 0;
571
572 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
573 return 1;
574 else
575 return 0;
576}
577
578/*
579 * Interface to link layer: send routine and receive handler.
580 */
581
582/*
583 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
584 * message.
585 */
586struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
587 struct net_device *dev, __be32 src_ip,
588 const unsigned char *dest_hw,
589 const unsigned char *src_hw,
590 const unsigned char *target_hw)
591{
592 struct sk_buff *skb;
593 struct arphdr *arp;
594 unsigned char *arp_ptr;
595
596 /*
597 * Allocate a buffer
598 */
599
600 skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
601 if (skb == NULL)
602 return NULL;
603
604 skb_reserve(skb, LL_RESERVED_SPACE(dev));
605 skb_reset_network_header(skb);
606 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
607 skb->dev = dev;
608 skb->protocol = htons(ETH_P_ARP);
609 if (src_hw == NULL)
610 src_hw = dev->dev_addr;
611 if (dest_hw == NULL)
612 dest_hw = dev->broadcast;
613
614 /*
615 * Fill the device header for the ARP frame
616 */
617 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
618 goto out;
619
620 /*
621 * Fill out the arp protocol part.
622 *
623 * The arp hardware type should match the device type, except for FDDI,
624 * which (according to RFC 1390) should always equal 1 (Ethernet).
625 */
626 /*
627 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
628 * DIX code for the protocol. Make these device structure fields.
629 */
630 switch (dev->type) {
631 default:
632 arp->ar_hrd = htons(dev->type);
633 arp->ar_pro = htons(ETH_P_IP);
634 break;
635
636#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
637 case ARPHRD_AX25:
638 arp->ar_hrd = htons(ARPHRD_AX25);
639 arp->ar_pro = htons(AX25_P_IP);
640 break;
641
642#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
643 case ARPHRD_NETROM:
644 arp->ar_hrd = htons(ARPHRD_NETROM);
645 arp->ar_pro = htons(AX25_P_IP);
646 break;
647#endif
648#endif
649
650#if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
651 case ARPHRD_FDDI:
652 arp->ar_hrd = htons(ARPHRD_ETHER);
653 arp->ar_pro = htons(ETH_P_IP);
654 break;
655#endif
656#if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
657 case ARPHRD_IEEE802_TR:
658 arp->ar_hrd = htons(ARPHRD_IEEE802);
659 arp->ar_pro = htons(ETH_P_IP);
660 break;
661#endif
662 }
663
664 arp->ar_hln = dev->addr_len;
665 arp->ar_pln = 4;
666 arp->ar_op = htons(type);
667
668 arp_ptr = (unsigned char *)(arp + 1);
669
670 memcpy(arp_ptr, src_hw, dev->addr_len);
671 arp_ptr += dev->addr_len;
672 memcpy(arp_ptr, &src_ip, 4);
673 arp_ptr += 4;
674 if (target_hw != NULL)
675 memcpy(arp_ptr, target_hw, dev->addr_len);
676 else
677 memset(arp_ptr, 0, dev->addr_len);
678 arp_ptr += dev->addr_len;
679 memcpy(arp_ptr, &dest_ip, 4);
680
681 return skb;
682
683out:
684 kfree_skb(skb);
685 return NULL;
686}
687EXPORT_SYMBOL(arp_create);
688
689/*
690 * Send an arp packet.
691 */
692void arp_xmit(struct sk_buff *skb)
693{
694 /* Send it off, maybe filter it using firewalling first. */
695 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
696}
697EXPORT_SYMBOL(arp_xmit);
698
699/*
700 * Create and send an arp packet.
701 */
702void arp_send(int type, int ptype, __be32 dest_ip,
703 struct net_device *dev, __be32 src_ip,
704 const unsigned char *dest_hw, const unsigned char *src_hw,
705 const unsigned char *target_hw)
706{
707 struct sk_buff *skb;
708
709 /*
710 * No arp on this interface.
711 */
712
713 if (dev->flags&IFF_NOARP)
714 return;
715
716 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
717 dest_hw, src_hw, target_hw);
718 if (skb == NULL)
719 return;
720
721 arp_xmit(skb);
722}
723EXPORT_SYMBOL(arp_send);
724
725/*
726 * Process an arp request.
727 */
728
729static int arp_process(struct sk_buff *skb)
730{
731 struct net_device *dev = skb->dev;
732 struct in_device *in_dev = __in_dev_get_rcu(dev);
733 struct arphdr *arp;
734 unsigned char *arp_ptr;
735 struct rtable *rt;
736 unsigned char *sha;
737 __be32 sip, tip;
738 u16 dev_type = dev->type;
739 int addr_type;
740 struct neighbour *n;
741 struct net *net = dev_net(dev);
742
743 /* arp_rcv below verifies the ARP header and verifies the device
744 * is ARP'able.
745 */
746
747 if (in_dev == NULL)
748 goto out;
749
750 arp = arp_hdr(skb);
751
752 switch (dev_type) {
753 default:
754 if (arp->ar_pro != htons(ETH_P_IP) ||
755 htons(dev_type) != arp->ar_hrd)
756 goto out;
757 break;
758 case ARPHRD_ETHER:
759 case ARPHRD_IEEE802_TR:
760 case ARPHRD_FDDI:
761 case ARPHRD_IEEE802:
762 /*
763 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
764 * devices, according to RFC 2625) devices will accept ARP
765 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
766 * This is the case also of FDDI, where the RFC 1390 says that
767 * FDDI devices should accept ARP hardware of (1) Ethernet,
768 * however, to be more robust, we'll accept both 1 (Ethernet)
769 * or 6 (IEEE 802.2)
770 */
771 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
772 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
773 arp->ar_pro != htons(ETH_P_IP))
774 goto out;
775 break;
776 case ARPHRD_AX25:
777 if (arp->ar_pro != htons(AX25_P_IP) ||
778 arp->ar_hrd != htons(ARPHRD_AX25))
779 goto out;
780 break;
781 case ARPHRD_NETROM:
782 if (arp->ar_pro != htons(AX25_P_IP) ||
783 arp->ar_hrd != htons(ARPHRD_NETROM))
784 goto out;
785 break;
786 }
787
788 /* Understand only these message types */
789
790 if (arp->ar_op != htons(ARPOP_REPLY) &&
791 arp->ar_op != htons(ARPOP_REQUEST))
792 goto out;
793
794/*
795 * Extract fields
796 */
797 arp_ptr = (unsigned char *)(arp + 1);
798 sha = arp_ptr;
799 arp_ptr += dev->addr_len;
800 memcpy(&sip, arp_ptr, 4);
801 arp_ptr += 4;
802 arp_ptr += dev->addr_len;
803 memcpy(&tip, arp_ptr, 4);
804/*
805 * Check for bad requests for 127.x.x.x and requests for multicast
806 * addresses. If this is one such, delete it.
807 */
808 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
809 goto out;
810
811/*
812 * Special case: We must set Frame Relay source Q.922 address
813 */
814 if (dev_type == ARPHRD_DLCI)
815 sha = dev->broadcast;
816
817/*
818 * Process entry. The idea here is we want to send a reply if it is a
819 * request for us or if it is a request for someone else that we hold
820 * a proxy for. We want to add an entry to our cache if it is a reply
821 * to us or if it is a request for our address.
822 * (The assumption for this last is that if someone is requesting our
823 * address, they are probably intending to talk to us, so it saves time
824 * if we cache their address. Their address is also probably not in
825 * our cache, since ours is not in their cache.)
826 *
827 * Putting this another way, we only care about replies if they are to
828 * us, in which case we add them to the cache. For requests, we care
829 * about those for us and those for our proxies. We reply to both,
830 * and in the case of requests for us we add the requester to the arp
831 * cache.
832 */
833
834 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
835 if (sip == 0) {
836 if (arp->ar_op == htons(ARPOP_REQUEST) &&
837 inet_addr_type(net, tip) == RTN_LOCAL &&
838 !arp_ignore(in_dev, sip, tip))
839 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
840 dev->dev_addr, sha);
841 goto out;
842 }
843
844 if (arp->ar_op == htons(ARPOP_REQUEST) &&
845 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
846
847 rt = skb_rtable(skb);
848 addr_type = rt->rt_type;
849
850 if (addr_type == RTN_LOCAL) {
851 int dont_send;
852
853 dont_send = arp_ignore(in_dev, sip, tip);
854 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
855 dont_send = arp_filter(sip, tip, dev);
856 if (!dont_send) {
857 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
858 if (n) {
859 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
860 dev, tip, sha, dev->dev_addr,
861 sha);
862 neigh_release(n);
863 }
864 }
865 goto out;
866 } else if (IN_DEV_FORWARD(in_dev)) {
867 if (addr_type == RTN_UNICAST &&
868 (arp_fwd_proxy(in_dev, dev, rt) ||
869 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
870 pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) {
871 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
872 if (n)
873 neigh_release(n);
874
875 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
876 skb->pkt_type == PACKET_HOST ||
877 in_dev->arp_parms->proxy_delay == 0) {
878 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
879 dev, tip, sha, dev->dev_addr,
880 sha);
881 } else {
882 pneigh_enqueue(&arp_tbl,
883 in_dev->arp_parms, skb);
884 return 0;
885 }
886 goto out;
887 }
888 }
889 }
890
891 /* Update our ARP tables */
892
893 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
894
895 if (IPV4_DEVCONF_ALL(dev_net(dev), ARP_ACCEPT)) {
896 /* Unsolicited ARP is not accepted by default.
897 It is possible, that this option should be enabled for some
898 devices (strip is candidate)
899 */
900 if (n == NULL &&
901 (arp->ar_op == htons(ARPOP_REPLY) ||
902 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) &&
903 inet_addr_type(net, sip) == RTN_UNICAST)
904 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
905 }
906
907 if (n) {
908 int state = NUD_REACHABLE;
909 int override;
910
911 /* If several different ARP replies follows back-to-back,
912 use the FIRST one. It is possible, if several proxy
913 agents are active. Taking the first reply prevents
914 arp trashing and chooses the fastest router.
915 */
916 override = time_after(jiffies, n->updated + n->parms->locktime);
917
918 /* Broadcast replies and request packets
919 do not assert neighbour reachability.
920 */
921 if (arp->ar_op != htons(ARPOP_REPLY) ||
922 skb->pkt_type != PACKET_HOST)
923 state = NUD_STALE;
924 neigh_update(n, sha, state,
925 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
926 neigh_release(n);
927 }
928
929out:
930 consume_skb(skb);
931 return 0;
932}
933
934static void parp_redo(struct sk_buff *skb)
935{
936 arp_process(skb);
937}
938
939
940/*
941 * Receive an arp request from the device layer.
942 */
943
944static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
945 struct packet_type *pt, struct net_device *orig_dev)
946{
947 struct arphdr *arp;
948
949 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
950 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
951 goto freeskb;
952
953 arp = arp_hdr(skb);
954 if (arp->ar_hln != dev->addr_len ||
955 dev->flags & IFF_NOARP ||
956 skb->pkt_type == PACKET_OTHERHOST ||
957 skb->pkt_type == PACKET_LOOPBACK ||
958 arp->ar_pln != 4)
959 goto freeskb;
960
961 skb = skb_share_check(skb, GFP_ATOMIC);
962 if (skb == NULL)
963 goto out_of_mem;
964
965 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
966
967 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
968
969freeskb:
970 kfree_skb(skb);
971out_of_mem:
972 return 0;
973}
974
975/*
976 * User level interface (ioctl)
977 */
978
979/*
980 * Set (create) an ARP cache entry.
981 */
982
983static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
984{
985 if (dev == NULL) {
986 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
987 return 0;
988 }
989 if (__in_dev_get_rtnl(dev)) {
990 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
991 return 0;
992 }
993 return -ENXIO;
994}
995
996static int arp_req_set_public(struct net *net, struct arpreq *r,
997 struct net_device *dev)
998{
999 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1000 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1001
1002 if (mask && mask != htonl(0xFFFFFFFF))
1003 return -EINVAL;
1004 if (!dev && (r->arp_flags & ATF_COM)) {
1005 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1006 r->arp_ha.sa_data);
1007 if (!dev)
1008 return -ENODEV;
1009 }
1010 if (mask) {
1011 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL)
1012 return -ENOBUFS;
1013 return 0;
1014 }
1015
1016 return arp_req_set_proxy(net, dev, 1);
1017}
1018
1019static int arp_req_set(struct net *net, struct arpreq *r,
1020 struct net_device *dev)
1021{
1022 __be32 ip;
1023 struct neighbour *neigh;
1024 int err;
1025
1026 if (r->arp_flags & ATF_PUBL)
1027 return arp_req_set_public(net, r, dev);
1028
1029 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1030 if (r->arp_flags & ATF_PERM)
1031 r->arp_flags |= ATF_COM;
1032 if (dev == NULL) {
1033 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1034
1035 if (IS_ERR(rt))
1036 return PTR_ERR(rt);
1037 dev = rt->dst.dev;
1038 ip_rt_put(rt);
1039 if (!dev)
1040 return -EINVAL;
1041 }
1042 switch (dev->type) {
1043#if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
1044 case ARPHRD_FDDI:
1045 /*
1046 * According to RFC 1390, FDDI devices should accept ARP
1047 * hardware types of 1 (Ethernet). However, to be more
1048 * robust, we'll accept hardware types of either 1 (Ethernet)
1049 * or 6 (IEEE 802.2).
1050 */
1051 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1052 r->arp_ha.sa_family != ARPHRD_ETHER &&
1053 r->arp_ha.sa_family != ARPHRD_IEEE802)
1054 return -EINVAL;
1055 break;
1056#endif
1057 default:
1058 if (r->arp_ha.sa_family != dev->type)
1059 return -EINVAL;
1060 break;
1061 }
1062
1063 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1064 err = PTR_ERR(neigh);
1065 if (!IS_ERR(neigh)) {
1066 unsigned state = NUD_STALE;
1067 if (r->arp_flags & ATF_PERM)
1068 state = NUD_PERMANENT;
1069 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1070 r->arp_ha.sa_data : NULL, state,
1071 NEIGH_UPDATE_F_OVERRIDE |
1072 NEIGH_UPDATE_F_ADMIN);
1073 neigh_release(neigh);
1074 }
1075 return err;
1076}
1077
1078static unsigned arp_state_to_flags(struct neighbour *neigh)
1079{
1080 if (neigh->nud_state&NUD_PERMANENT)
1081 return ATF_PERM | ATF_COM;
1082 else if (neigh->nud_state&NUD_VALID)
1083 return ATF_COM;
1084 else
1085 return 0;
1086}
1087
1088/*
1089 * Get an ARP cache entry.
1090 */
1091
1092static int arp_req_get(struct arpreq *r, struct net_device *dev)
1093{
1094 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1095 struct neighbour *neigh;
1096 int err = -ENXIO;
1097
1098 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1099 if (neigh) {
1100 read_lock_bh(&neigh->lock);
1101 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1102 r->arp_flags = arp_state_to_flags(neigh);
1103 read_unlock_bh(&neigh->lock);
1104 r->arp_ha.sa_family = dev->type;
1105 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1106 neigh_release(neigh);
1107 err = 0;
1108 }
1109 return err;
1110}
1111
1112int arp_invalidate(struct net_device *dev, __be32 ip)
1113{
1114 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1115 int err = -ENXIO;
1116
1117 if (neigh) {
1118 if (neigh->nud_state & ~NUD_NOARP)
1119 err = neigh_update(neigh, NULL, NUD_FAILED,
1120 NEIGH_UPDATE_F_OVERRIDE|
1121 NEIGH_UPDATE_F_ADMIN);
1122 neigh_release(neigh);
1123 }
1124
1125 return err;
1126}
1127EXPORT_SYMBOL(arp_invalidate);
1128
1129static int arp_req_delete_public(struct net *net, struct arpreq *r,
1130 struct net_device *dev)
1131{
1132 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1133 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1134
1135 if (mask == htonl(0xFFFFFFFF))
1136 return pneigh_delete(&arp_tbl, net, &ip, dev);
1137
1138 if (mask)
1139 return -EINVAL;
1140
1141 return arp_req_set_proxy(net, dev, 0);
1142}
1143
1144static int arp_req_delete(struct net *net, struct arpreq *r,
1145 struct net_device *dev)
1146{
1147 __be32 ip;
1148
1149 if (r->arp_flags & ATF_PUBL)
1150 return arp_req_delete_public(net, r, dev);
1151
1152 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1153 if (dev == NULL) {
1154 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1155 if (IS_ERR(rt))
1156 return PTR_ERR(rt);
1157 dev = rt->dst.dev;
1158 ip_rt_put(rt);
1159 if (!dev)
1160 return -EINVAL;
1161 }
1162 return arp_invalidate(dev, ip);
1163}
1164
1165/*
1166 * Handle an ARP layer I/O control request.
1167 */
1168
1169int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1170{
1171 int err;
1172 struct arpreq r;
1173 struct net_device *dev = NULL;
1174
1175 switch (cmd) {
1176 case SIOCDARP:
1177 case SIOCSARP:
1178 if (!capable(CAP_NET_ADMIN))
1179 return -EPERM;
1180 case SIOCGARP:
1181 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1182 if (err)
1183 return -EFAULT;
1184 break;
1185 default:
1186 return -EINVAL;
1187 }
1188
1189 if (r.arp_pa.sa_family != AF_INET)
1190 return -EPFNOSUPPORT;
1191
1192 if (!(r.arp_flags & ATF_PUBL) &&
1193 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1194 return -EINVAL;
1195 if (!(r.arp_flags & ATF_NETMASK))
1196 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1197 htonl(0xFFFFFFFFUL);
1198 rtnl_lock();
1199 if (r.arp_dev[0]) {
1200 err = -ENODEV;
1201 dev = __dev_get_by_name(net, r.arp_dev);
1202 if (dev == NULL)
1203 goto out;
1204
1205 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1206 if (!r.arp_ha.sa_family)
1207 r.arp_ha.sa_family = dev->type;
1208 err = -EINVAL;
1209 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1210 goto out;
1211 } else if (cmd == SIOCGARP) {
1212 err = -ENODEV;
1213 goto out;
1214 }
1215
1216 switch (cmd) {
1217 case SIOCDARP:
1218 err = arp_req_delete(net, &r, dev);
1219 break;
1220 case SIOCSARP:
1221 err = arp_req_set(net, &r, dev);
1222 break;
1223 case SIOCGARP:
1224 err = arp_req_get(&r, dev);
1225 break;
1226 }
1227out:
1228 rtnl_unlock();
1229 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1230 err = -EFAULT;
1231 return err;
1232}
1233
1234static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1235 void *ptr)
1236{
1237 struct net_device *dev = ptr;
1238
1239 switch (event) {
1240 case NETDEV_CHANGEADDR:
1241 neigh_changeaddr(&arp_tbl, dev);
1242 rt_cache_flush(dev_net(dev), 0);
1243 break;
1244 default:
1245 break;
1246 }
1247
1248 return NOTIFY_DONE;
1249}
1250
1251static struct notifier_block arp_netdev_notifier = {
1252 .notifier_call = arp_netdev_event,
1253};
1254
1255/* Note, that it is not on notifier chain.
1256 It is necessary, that this routine was called after route cache will be
1257 flushed.
1258 */
1259void arp_ifdown(struct net_device *dev)
1260{
1261 neigh_ifdown(&arp_tbl, dev);
1262}
1263
1264
1265/*
1266 * Called once on startup.
1267 */
1268
1269static struct packet_type arp_packet_type __read_mostly = {
1270 .type = cpu_to_be16(ETH_P_ARP),
1271 .func = arp_rcv,
1272};
1273
1274static int arp_proc_init(void);
1275
1276void __init arp_init(void)
1277{
1278 neigh_table_init(&arp_tbl);
1279
1280 dev_add_pack(&arp_packet_type);
1281 arp_proc_init();
1282#ifdef CONFIG_SYSCTL
1283 neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL);
1284#endif
1285 register_netdevice_notifier(&arp_netdev_notifier);
1286}
1287
1288#ifdef CONFIG_PROC_FS
1289#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1290
1291/* ------------------------------------------------------------------------ */
1292/*
1293 * ax25 -> ASCII conversion
1294 */
1295static char *ax2asc2(ax25_address *a, char *buf)
1296{
1297 char c, *s;
1298 int n;
1299
1300 for (n = 0, s = buf; n < 6; n++) {
1301 c = (a->ax25_call[n] >> 1) & 0x7F;
1302
1303 if (c != ' ')
1304 *s++ = c;
1305 }
1306
1307 *s++ = '-';
1308 n = (a->ax25_call[6] >> 1) & 0x0F;
1309 if (n > 9) {
1310 *s++ = '1';
1311 n -= 10;
1312 }
1313
1314 *s++ = n + '0';
1315 *s++ = '\0';
1316
1317 if (*buf == '\0' || *buf == '-')
1318 return "*";
1319
1320 return buf;
1321}
1322#endif /* CONFIG_AX25 */
1323
1324#define HBUFFERLEN 30
1325
1326static void arp_format_neigh_entry(struct seq_file *seq,
1327 struct neighbour *n)
1328{
1329 char hbuffer[HBUFFERLEN];
1330 int k, j;
1331 char tbuf[16];
1332 struct net_device *dev = n->dev;
1333 int hatype = dev->type;
1334
1335 read_lock(&n->lock);
1336 /* Convert hardware address to XX:XX:XX:XX ... form. */
1337#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1338 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1339 ax2asc2((ax25_address *)n->ha, hbuffer);
1340 else {
1341#endif
1342 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1343 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1344 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1345 hbuffer[k++] = ':';
1346 }
1347 if (k != 0)
1348 --k;
1349 hbuffer[k] = 0;
1350#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1351 }
1352#endif
1353 sprintf(tbuf, "%pI4", n->primary_key);
1354 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1355 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1356 read_unlock(&n->lock);
1357}
1358
1359static void arp_format_pneigh_entry(struct seq_file *seq,
1360 struct pneigh_entry *n)
1361{
1362 struct net_device *dev = n->dev;
1363 int hatype = dev ? dev->type : 0;
1364 char tbuf[16];
1365
1366 sprintf(tbuf, "%pI4", n->key);
1367 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1368 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1369 dev ? dev->name : "*");
1370}
1371
1372static int arp_seq_show(struct seq_file *seq, void *v)
1373{
1374 if (v == SEQ_START_TOKEN) {
1375 seq_puts(seq, "IP address HW type Flags "
1376 "HW address Mask Device\n");
1377 } else {
1378 struct neigh_seq_state *state = seq->private;
1379
1380 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1381 arp_format_pneigh_entry(seq, v);
1382 else
1383 arp_format_neigh_entry(seq, v);
1384 }
1385
1386 return 0;
1387}
1388
1389static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1390{
1391 /* Don't want to confuse "arp -a" w/ magic entries,
1392 * so we tell the generic iterator to skip NUD_NOARP.
1393 */
1394 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1395}
1396
1397/* ------------------------------------------------------------------------ */
1398
1399static const struct seq_operations arp_seq_ops = {
1400 .start = arp_seq_start,
1401 .next = neigh_seq_next,
1402 .stop = neigh_seq_stop,
1403 .show = arp_seq_show,
1404};
1405
1406static int arp_seq_open(struct inode *inode, struct file *file)
1407{
1408 return seq_open_net(inode, file, &arp_seq_ops,
1409 sizeof(struct neigh_seq_state));
1410}
1411
1412static const struct file_operations arp_seq_fops = {
1413 .owner = THIS_MODULE,
1414 .open = arp_seq_open,
1415 .read = seq_read,
1416 .llseek = seq_lseek,
1417 .release = seq_release_net,
1418};
1419
1420
1421static int __net_init arp_net_init(struct net *net)
1422{
1423 if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops))
1424 return -ENOMEM;
1425 return 0;
1426}
1427
1428static void __net_exit arp_net_exit(struct net *net)
1429{
1430 proc_net_remove(net, "arp");
1431}
1432
1433static struct pernet_operations arp_net_ops = {
1434 .init = arp_net_init,
1435 .exit = arp_net_exit,
1436};
1437
1438static int __init arp_proc_init(void)
1439{
1440 return register_pernet_subsys(&arp_net_ops);
1441}
1442
1443#else /* CONFIG_PROC_FS */
1444
1445static int __init arp_proc_init(void)
1446{
1447 return 0;
1448}
1449
1450#endif /* CONFIG_PROC_FS */