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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#include <net/dst_metadata.h>
117#include <net/ip_tunnels.h>
118
119#include <linux/uaccess.h>
120
121#include <linux/netfilter_arp.h>
122
123/*
124 * Interface to generic neighbour cache.
125 */
126static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
127static bool arp_key_eq(const struct neighbour *n, const void *pkey);
128static int arp_constructor(struct neighbour *neigh);
129static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
130static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
131static void parp_redo(struct sk_buff *skb);
132
133static const struct neigh_ops arp_generic_ops = {
134 .family = AF_INET,
135 .solicit = arp_solicit,
136 .error_report = arp_error_report,
137 .output = neigh_resolve_output,
138 .connected_output = neigh_connected_output,
139};
140
141static const struct neigh_ops arp_hh_ops = {
142 .family = AF_INET,
143 .solicit = arp_solicit,
144 .error_report = arp_error_report,
145 .output = neigh_resolve_output,
146 .connected_output = neigh_resolve_output,
147};
148
149static const struct neigh_ops arp_direct_ops = {
150 .family = AF_INET,
151 .output = neigh_direct_output,
152 .connected_output = neigh_direct_output,
153};
154
155struct neigh_table arp_tbl = {
156 .family = AF_INET,
157 .key_len = 4,
158 .protocol = cpu_to_be16(ETH_P_IP),
159 .hash = arp_hash,
160 .key_eq = arp_key_eq,
161 .constructor = arp_constructor,
162 .proxy_redo = parp_redo,
163 .id = "arp_cache",
164 .parms = {
165 .tbl = &arp_tbl,
166 .reachable_time = 30 * HZ,
167 .data = {
168 [NEIGH_VAR_MCAST_PROBES] = 3,
169 [NEIGH_VAR_UCAST_PROBES] = 3,
170 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
171 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
172 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
173 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
174 [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
175 [NEIGH_VAR_PROXY_QLEN] = 64,
176 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
177 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
178 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
179 },
180 },
181 .gc_interval = 30 * HZ,
182 .gc_thresh1 = 128,
183 .gc_thresh2 = 512,
184 .gc_thresh3 = 1024,
185};
186EXPORT_SYMBOL(arp_tbl);
187
188int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
189{
190 switch (dev->type) {
191 case ARPHRD_ETHER:
192 case ARPHRD_FDDI:
193 case ARPHRD_IEEE802:
194 ip_eth_mc_map(addr, haddr);
195 return 0;
196 case ARPHRD_INFINIBAND:
197 ip_ib_mc_map(addr, dev->broadcast, haddr);
198 return 0;
199 case ARPHRD_IPGRE:
200 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
201 return 0;
202 default:
203 if (dir) {
204 memcpy(haddr, dev->broadcast, dev->addr_len);
205 return 0;
206 }
207 }
208 return -EINVAL;
209}
210
211
212static u32 arp_hash(const void *pkey,
213 const struct net_device *dev,
214 __u32 *hash_rnd)
215{
216 return arp_hashfn(pkey, dev, hash_rnd);
217}
218
219static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
220{
221 return neigh_key_eq32(neigh, pkey);
222}
223
224static int arp_constructor(struct neighbour *neigh)
225{
226 __be32 addr = *(__be32 *)neigh->primary_key;
227 struct net_device *dev = neigh->dev;
228 struct in_device *in_dev;
229 struct neigh_parms *parms;
230
231 rcu_read_lock();
232 in_dev = __in_dev_get_rcu(dev);
233 if (!in_dev) {
234 rcu_read_unlock();
235 return -EINVAL;
236 }
237
238 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
239
240 parms = in_dev->arp_parms;
241 __neigh_parms_put(neigh->parms);
242 neigh->parms = neigh_parms_clone(parms);
243 rcu_read_unlock();
244
245 if (!dev->header_ops) {
246 neigh->nud_state = NUD_NOARP;
247 neigh->ops = &arp_direct_ops;
248 neigh->output = neigh_direct_output;
249 } else {
250 /* Good devices (checked by reading texts, but only Ethernet is
251 tested)
252
253 ARPHRD_ETHER: (ethernet, apfddi)
254 ARPHRD_FDDI: (fddi)
255 ARPHRD_IEEE802: (tr)
256 ARPHRD_METRICOM: (strip)
257 ARPHRD_ARCNET:
258 etc. etc. etc.
259
260 ARPHRD_IPDDP will also work, if author repairs it.
261 I did not it, because this driver does not work even
262 in old paradigm.
263 */
264
265 if (neigh->type == RTN_MULTICAST) {
266 neigh->nud_state = NUD_NOARP;
267 arp_mc_map(addr, neigh->ha, dev, 1);
268 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
269 neigh->nud_state = NUD_NOARP;
270 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
271 } else if (neigh->type == RTN_BROADCAST ||
272 (dev->flags & IFF_POINTOPOINT)) {
273 neigh->nud_state = NUD_NOARP;
274 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
275 }
276
277 if (dev->header_ops->cache)
278 neigh->ops = &arp_hh_ops;
279 else
280 neigh->ops = &arp_generic_ops;
281
282 if (neigh->nud_state & NUD_VALID)
283 neigh->output = neigh->ops->connected_output;
284 else
285 neigh->output = neigh->ops->output;
286 }
287 return 0;
288}
289
290static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
291{
292 dst_link_failure(skb);
293 kfree_skb(skb);
294}
295
296/* Create and send an arp packet. */
297static void arp_send_dst(int type, int ptype, __be32 dest_ip,
298 struct net_device *dev, __be32 src_ip,
299 const unsigned char *dest_hw,
300 const unsigned char *src_hw,
301 const unsigned char *target_hw,
302 struct dst_entry *dst)
303{
304 struct sk_buff *skb;
305
306 /* arp on this interface. */
307 if (dev->flags & IFF_NOARP)
308 return;
309
310 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
311 dest_hw, src_hw, target_hw);
312 if (!skb)
313 return;
314
315 skb_dst_set(skb, dst_clone(dst));
316 arp_xmit(skb);
317}
318
319void arp_send(int type, int ptype, __be32 dest_ip,
320 struct net_device *dev, __be32 src_ip,
321 const unsigned char *dest_hw, const unsigned char *src_hw,
322 const unsigned char *target_hw)
323{
324 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
325 target_hw, NULL);
326}
327EXPORT_SYMBOL(arp_send);
328
329static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
330{
331 __be32 saddr = 0;
332 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
333 struct net_device *dev = neigh->dev;
334 __be32 target = *(__be32 *)neigh->primary_key;
335 int probes = atomic_read(&neigh->probes);
336 struct in_device *in_dev;
337 struct dst_entry *dst = NULL;
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_table(dev_net(dev), 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_table(dev_net(dev), dev,
357 saddr) == RTN_LOCAL) {
358 /* saddr should be known to target */
359 if (inet_addr_onlink(in_dev, target, saddr))
360 break;
361 }
362 saddr = 0;
363 break;
364 case 2: /* Avoid secondary IPs, get a primary/preferred one */
365 break;
366 }
367 rcu_read_unlock();
368
369 if (!saddr)
370 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
371
372 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
373 if (probes < 0) {
374 if (!(neigh->nud_state & NUD_VALID))
375 pr_debug("trying to ucast probe in NUD_INVALID\n");
376 neigh_ha_snapshot(dst_ha, neigh, dev);
377 dst_hw = dst_ha;
378 } else {
379 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
380 if (probes < 0) {
381 neigh_app_ns(neigh);
382 return;
383 }
384 }
385
386 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
387 dst = skb_dst(skb);
388 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
389 dst_hw, dev->dev_addr, NULL, dst);
390}
391
392static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
393{
394 struct net *net = dev_net(in_dev->dev);
395 int scope;
396
397 switch (IN_DEV_ARP_IGNORE(in_dev)) {
398 case 0: /* Reply, the tip is already validated */
399 return 0;
400 case 1: /* Reply only if tip is configured on the incoming interface */
401 sip = 0;
402 scope = RT_SCOPE_HOST;
403 break;
404 case 2: /*
405 * Reply only if tip is configured on the incoming interface
406 * and is in same subnet as sip
407 */
408 scope = RT_SCOPE_HOST;
409 break;
410 case 3: /* Do not reply for scope host addresses */
411 sip = 0;
412 scope = RT_SCOPE_LINK;
413 in_dev = NULL;
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(net, 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/*
447 * Check if we can use proxy ARP for this path
448 */
449static inline int arp_fwd_proxy(struct in_device *in_dev,
450 struct net_device *dev, struct rtable *rt)
451{
452 struct in_device *out_dev;
453 int imi, omi = -1;
454
455 if (rt->dst.dev == dev)
456 return 0;
457
458 if (!IN_DEV_PROXY_ARP(in_dev))
459 return 0;
460 imi = IN_DEV_MEDIUM_ID(in_dev);
461 if (imi == 0)
462 return 1;
463 if (imi == -1)
464 return 0;
465
466 /* place to check for proxy_arp for routes */
467
468 out_dev = __in_dev_get_rcu(rt->dst.dev);
469 if (out_dev)
470 omi = IN_DEV_MEDIUM_ID(out_dev);
471
472 return omi != imi && omi != -1;
473}
474
475/*
476 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
477 *
478 * RFC3069 supports proxy arp replies back to the same interface. This
479 * is done to support (ethernet) switch features, like RFC 3069, where
480 * the individual ports are not allowed to communicate with each
481 * other, BUT they are allowed to talk to the upstream router. As
482 * described in RFC 3069, it is possible to allow these hosts to
483 * communicate through the upstream router, by proxy_arp'ing.
484 *
485 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
486 *
487 * This technology is known by different names:
488 * In RFC 3069 it is called VLAN Aggregation.
489 * Cisco and Allied Telesyn call it Private VLAN.
490 * Hewlett-Packard call it Source-Port filtering or port-isolation.
491 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
492 *
493 */
494static inline int arp_fwd_pvlan(struct in_device *in_dev,
495 struct net_device *dev, struct rtable *rt,
496 __be32 sip, __be32 tip)
497{
498 /* Private VLAN is only concerned about the same ethernet segment */
499 if (rt->dst.dev != dev)
500 return 0;
501
502 /* Don't reply on self probes (often done by windowz boxes)*/
503 if (sip == tip)
504 return 0;
505
506 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
507 return 1;
508 else
509 return 0;
510}
511
512/*
513 * Interface to link layer: send routine and receive handler.
514 */
515
516/*
517 * Create an arp packet. If dest_hw is not set, we create a broadcast
518 * message.
519 */
520struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
521 struct net_device *dev, __be32 src_ip,
522 const unsigned char *dest_hw,
523 const unsigned char *src_hw,
524 const unsigned char *target_hw)
525{
526 struct sk_buff *skb;
527 struct arphdr *arp;
528 unsigned char *arp_ptr;
529 int hlen = LL_RESERVED_SPACE(dev);
530 int tlen = dev->needed_tailroom;
531
532 /*
533 * Allocate a buffer
534 */
535
536 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
537 if (!skb)
538 return NULL;
539
540 skb_reserve(skb, hlen);
541 skb_reset_network_header(skb);
542 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
543 skb->dev = dev;
544 skb->protocol = htons(ETH_P_ARP);
545 if (!src_hw)
546 src_hw = dev->dev_addr;
547 if (!dest_hw)
548 dest_hw = dev->broadcast;
549
550 /*
551 * Fill the device header for the ARP frame
552 */
553 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
554 goto out;
555
556 /*
557 * Fill out the arp protocol part.
558 *
559 * The arp hardware type should match the device type, except for FDDI,
560 * which (according to RFC 1390) should always equal 1 (Ethernet).
561 */
562 /*
563 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
564 * DIX code for the protocol. Make these device structure fields.
565 */
566 switch (dev->type) {
567 default:
568 arp->ar_hrd = htons(dev->type);
569 arp->ar_pro = htons(ETH_P_IP);
570 break;
571
572#if IS_ENABLED(CONFIG_AX25)
573 case ARPHRD_AX25:
574 arp->ar_hrd = htons(ARPHRD_AX25);
575 arp->ar_pro = htons(AX25_P_IP);
576 break;
577
578#if IS_ENABLED(CONFIG_NETROM)
579 case ARPHRD_NETROM:
580 arp->ar_hrd = htons(ARPHRD_NETROM);
581 arp->ar_pro = htons(AX25_P_IP);
582 break;
583#endif
584#endif
585
586#if IS_ENABLED(CONFIG_FDDI)
587 case ARPHRD_FDDI:
588 arp->ar_hrd = htons(ARPHRD_ETHER);
589 arp->ar_pro = htons(ETH_P_IP);
590 break;
591#endif
592 }
593
594 arp->ar_hln = dev->addr_len;
595 arp->ar_pln = 4;
596 arp->ar_op = htons(type);
597
598 arp_ptr = (unsigned char *)(arp + 1);
599
600 memcpy(arp_ptr, src_hw, dev->addr_len);
601 arp_ptr += dev->addr_len;
602 memcpy(arp_ptr, &src_ip, 4);
603 arp_ptr += 4;
604
605 switch (dev->type) {
606#if IS_ENABLED(CONFIG_FIREWIRE_NET)
607 case ARPHRD_IEEE1394:
608 break;
609#endif
610 default:
611 if (target_hw)
612 memcpy(arp_ptr, target_hw, dev->addr_len);
613 else
614 memset(arp_ptr, 0, dev->addr_len);
615 arp_ptr += dev->addr_len;
616 }
617 memcpy(arp_ptr, &dest_ip, 4);
618
619 return skb;
620
621out:
622 kfree_skb(skb);
623 return NULL;
624}
625EXPORT_SYMBOL(arp_create);
626
627static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
628{
629 return dev_queue_xmit(skb);
630}
631
632/*
633 * Send an arp packet.
634 */
635void arp_xmit(struct sk_buff *skb)
636{
637 /* Send it off, maybe filter it using firewalling first. */
638 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
639 dev_net(skb->dev), NULL, skb, NULL, skb->dev,
640 arp_xmit_finish);
641}
642EXPORT_SYMBOL(arp_xmit);
643
644/*
645 * Process an arp request.
646 */
647
648static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
649{
650 struct net_device *dev = skb->dev;
651 struct in_device *in_dev = __in_dev_get_rcu(dev);
652 struct arphdr *arp;
653 unsigned char *arp_ptr;
654 struct rtable *rt;
655 unsigned char *sha;
656 __be32 sip, tip;
657 u16 dev_type = dev->type;
658 int addr_type;
659 struct neighbour *n;
660 struct dst_entry *reply_dst = NULL;
661 bool is_garp = false;
662
663 /* arp_rcv below verifies the ARP header and verifies the device
664 * is ARP'able.
665 */
666
667 if (!in_dev)
668 goto out_free_skb;
669
670 arp = arp_hdr(skb);
671
672 switch (dev_type) {
673 default:
674 if (arp->ar_pro != htons(ETH_P_IP) ||
675 htons(dev_type) != arp->ar_hrd)
676 goto out_free_skb;
677 break;
678 case ARPHRD_ETHER:
679 case ARPHRD_FDDI:
680 case ARPHRD_IEEE802:
681 /*
682 * ETHERNET, and Fibre Channel (which are IEEE 802
683 * devices, according to RFC 2625) devices will accept ARP
684 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
685 * This is the case also of FDDI, where the RFC 1390 says that
686 * FDDI devices should accept ARP hardware of (1) Ethernet,
687 * however, to be more robust, we'll accept both 1 (Ethernet)
688 * or 6 (IEEE 802.2)
689 */
690 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
691 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
692 arp->ar_pro != htons(ETH_P_IP))
693 goto out_free_skb;
694 break;
695 case ARPHRD_AX25:
696 if (arp->ar_pro != htons(AX25_P_IP) ||
697 arp->ar_hrd != htons(ARPHRD_AX25))
698 goto out_free_skb;
699 break;
700 case ARPHRD_NETROM:
701 if (arp->ar_pro != htons(AX25_P_IP) ||
702 arp->ar_hrd != htons(ARPHRD_NETROM))
703 goto out_free_skb;
704 break;
705 }
706
707 /* Understand only these message types */
708
709 if (arp->ar_op != htons(ARPOP_REPLY) &&
710 arp->ar_op != htons(ARPOP_REQUEST))
711 goto out_free_skb;
712
713/*
714 * Extract fields
715 */
716 arp_ptr = (unsigned char *)(arp + 1);
717 sha = arp_ptr;
718 arp_ptr += dev->addr_len;
719 memcpy(&sip, arp_ptr, 4);
720 arp_ptr += 4;
721 switch (dev_type) {
722#if IS_ENABLED(CONFIG_FIREWIRE_NET)
723 case ARPHRD_IEEE1394:
724 break;
725#endif
726 default:
727 arp_ptr += dev->addr_len;
728 }
729 memcpy(&tip, arp_ptr, 4);
730/*
731 * Check for bad requests for 127.x.x.x and requests for multicast
732 * addresses. If this is one such, delete it.
733 */
734 if (ipv4_is_multicast(tip) ||
735 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
736 goto out_free_skb;
737
738 /*
739 * For some 802.11 wireless deployments (and possibly other networks),
740 * there will be an ARP proxy and gratuitous ARP frames are attacks
741 * and thus should not be accepted.
742 */
743 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
744 goto out_free_skb;
745
746/*
747 * Special case: We must set Frame Relay source Q.922 address
748 */
749 if (dev_type == ARPHRD_DLCI)
750 sha = dev->broadcast;
751
752/*
753 * Process entry. The idea here is we want to send a reply if it is a
754 * request for us or if it is a request for someone else that we hold
755 * a proxy for. We want to add an entry to our cache if it is a reply
756 * to us or if it is a request for our address.
757 * (The assumption for this last is that if someone is requesting our
758 * address, they are probably intending to talk to us, so it saves time
759 * if we cache their address. Their address is also probably not in
760 * our cache, since ours is not in their cache.)
761 *
762 * Putting this another way, we only care about replies if they are to
763 * us, in which case we add them to the cache. For requests, we care
764 * about those for us and those for our proxies. We reply to both,
765 * and in the case of requests for us we add the requester to the arp
766 * cache.
767 */
768
769 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
770 reply_dst = (struct dst_entry *)
771 iptunnel_metadata_reply(skb_metadata_dst(skb),
772 GFP_ATOMIC);
773
774 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
775 if (sip == 0) {
776 if (arp->ar_op == htons(ARPOP_REQUEST) &&
777 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
778 !arp_ignore(in_dev, sip, tip))
779 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
780 sha, dev->dev_addr, sha, reply_dst);
781 goto out_consume_skb;
782 }
783
784 if (arp->ar_op == htons(ARPOP_REQUEST) &&
785 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
786
787 rt = skb_rtable(skb);
788 addr_type = rt->rt_type;
789
790 if (addr_type == RTN_LOCAL) {
791 int dont_send;
792
793 dont_send = arp_ignore(in_dev, sip, tip);
794 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
795 dont_send = arp_filter(sip, tip, dev);
796 if (!dont_send) {
797 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
798 if (n) {
799 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
800 sip, dev, tip, sha,
801 dev->dev_addr, sha,
802 reply_dst);
803 neigh_release(n);
804 }
805 }
806 goto out_consume_skb;
807 } else if (IN_DEV_FORWARD(in_dev)) {
808 if (addr_type == RTN_UNICAST &&
809 (arp_fwd_proxy(in_dev, dev, rt) ||
810 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
811 (rt->dst.dev != dev &&
812 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
813 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
814 if (n)
815 neigh_release(n);
816
817 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
818 skb->pkt_type == PACKET_HOST ||
819 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
820 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
821 sip, dev, tip, sha,
822 dev->dev_addr, sha,
823 reply_dst);
824 } else {
825 pneigh_enqueue(&arp_tbl,
826 in_dev->arp_parms, skb);
827 goto out_free_dst;
828 }
829 goto out_consume_skb;
830 }
831 }
832 }
833
834 /* Update our ARP tables */
835
836 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
837
838 if (IN_DEV_ARP_ACCEPT(in_dev)) {
839 unsigned int addr_type = inet_addr_type_dev_table(net, dev, sip);
840
841 /* Unsolicited ARP is not accepted by default.
842 It is possible, that this option should be enabled for some
843 devices (strip is candidate)
844 */
845 is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip &&
846 addr_type == RTN_UNICAST;
847
848 if (!n &&
849 ((arp->ar_op == htons(ARPOP_REPLY) &&
850 addr_type == RTN_UNICAST) || is_garp))
851 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
852 }
853
854 if (n) {
855 int state = NUD_REACHABLE;
856 int override;
857
858 /* If several different ARP replies follows back-to-back,
859 use the FIRST one. It is possible, if several proxy
860 agents are active. Taking the first reply prevents
861 arp trashing and chooses the fastest router.
862 */
863 override = time_after(jiffies,
864 n->updated +
865 NEIGH_VAR(n->parms, LOCKTIME)) ||
866 is_garp;
867
868 /* Broadcast replies and request packets
869 do not assert neighbour reachability.
870 */
871 if (arp->ar_op != htons(ARPOP_REPLY) ||
872 skb->pkt_type != PACKET_HOST)
873 state = NUD_STALE;
874 neigh_update(n, sha, state,
875 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
876 neigh_release(n);
877 }
878
879out_consume_skb:
880 consume_skb(skb);
881
882out_free_dst:
883 dst_release(reply_dst);
884 return NET_RX_SUCCESS;
885
886out_free_skb:
887 kfree_skb(skb);
888 return NET_RX_DROP;
889}
890
891static void parp_redo(struct sk_buff *skb)
892{
893 arp_process(dev_net(skb->dev), NULL, skb);
894}
895
896
897/*
898 * Receive an arp request from the device layer.
899 */
900
901static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
902 struct packet_type *pt, struct net_device *orig_dev)
903{
904 const struct arphdr *arp;
905
906 /* do not tweak dropwatch on an ARP we will ignore */
907 if (dev->flags & IFF_NOARP ||
908 skb->pkt_type == PACKET_OTHERHOST ||
909 skb->pkt_type == PACKET_LOOPBACK)
910 goto consumeskb;
911
912 skb = skb_share_check(skb, GFP_ATOMIC);
913 if (!skb)
914 goto out_of_mem;
915
916 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
917 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
918 goto freeskb;
919
920 arp = arp_hdr(skb);
921 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
922 goto freeskb;
923
924 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
925
926 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
927 dev_net(dev), NULL, skb, dev, NULL,
928 arp_process);
929
930consumeskb:
931 consume_skb(skb);
932 return NET_RX_SUCCESS;
933freeskb:
934 kfree_skb(skb);
935out_of_mem:
936 return NET_RX_DROP;
937}
938
939/*
940 * User level interface (ioctl)
941 */
942
943/*
944 * Set (create) an ARP cache entry.
945 */
946
947static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
948{
949 if (!dev) {
950 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
951 return 0;
952 }
953 if (__in_dev_get_rtnl(dev)) {
954 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
955 return 0;
956 }
957 return -ENXIO;
958}
959
960static int arp_req_set_public(struct net *net, struct arpreq *r,
961 struct net_device *dev)
962{
963 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
964 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
965
966 if (mask && mask != htonl(0xFFFFFFFF))
967 return -EINVAL;
968 if (!dev && (r->arp_flags & ATF_COM)) {
969 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
970 r->arp_ha.sa_data);
971 if (!dev)
972 return -ENODEV;
973 }
974 if (mask) {
975 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
976 return -ENOBUFS;
977 return 0;
978 }
979
980 return arp_req_set_proxy(net, dev, 1);
981}
982
983static int arp_req_set(struct net *net, struct arpreq *r,
984 struct net_device *dev)
985{
986 __be32 ip;
987 struct neighbour *neigh;
988 int err;
989
990 if (r->arp_flags & ATF_PUBL)
991 return arp_req_set_public(net, r, dev);
992
993 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
994 if (r->arp_flags & ATF_PERM)
995 r->arp_flags |= ATF_COM;
996 if (!dev) {
997 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
998
999 if (IS_ERR(rt))
1000 return PTR_ERR(rt);
1001 dev = rt->dst.dev;
1002 ip_rt_put(rt);
1003 if (!dev)
1004 return -EINVAL;
1005 }
1006 switch (dev->type) {
1007#if IS_ENABLED(CONFIG_FDDI)
1008 case ARPHRD_FDDI:
1009 /*
1010 * According to RFC 1390, FDDI devices should accept ARP
1011 * hardware types of 1 (Ethernet). However, to be more
1012 * robust, we'll accept hardware types of either 1 (Ethernet)
1013 * or 6 (IEEE 802.2).
1014 */
1015 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1016 r->arp_ha.sa_family != ARPHRD_ETHER &&
1017 r->arp_ha.sa_family != ARPHRD_IEEE802)
1018 return -EINVAL;
1019 break;
1020#endif
1021 default:
1022 if (r->arp_ha.sa_family != dev->type)
1023 return -EINVAL;
1024 break;
1025 }
1026
1027 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1028 err = PTR_ERR(neigh);
1029 if (!IS_ERR(neigh)) {
1030 unsigned int state = NUD_STALE;
1031 if (r->arp_flags & ATF_PERM)
1032 state = NUD_PERMANENT;
1033 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1034 r->arp_ha.sa_data : NULL, state,
1035 NEIGH_UPDATE_F_OVERRIDE |
1036 NEIGH_UPDATE_F_ADMIN);
1037 neigh_release(neigh);
1038 }
1039 return err;
1040}
1041
1042static unsigned int arp_state_to_flags(struct neighbour *neigh)
1043{
1044 if (neigh->nud_state&NUD_PERMANENT)
1045 return ATF_PERM | ATF_COM;
1046 else if (neigh->nud_state&NUD_VALID)
1047 return ATF_COM;
1048 else
1049 return 0;
1050}
1051
1052/*
1053 * Get an ARP cache entry.
1054 */
1055
1056static int arp_req_get(struct arpreq *r, struct net_device *dev)
1057{
1058 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1059 struct neighbour *neigh;
1060 int err = -ENXIO;
1061
1062 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1063 if (neigh) {
1064 if (!(neigh->nud_state & NUD_NOARP)) {
1065 read_lock_bh(&neigh->lock);
1066 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1067 r->arp_flags = arp_state_to_flags(neigh);
1068 read_unlock_bh(&neigh->lock);
1069 r->arp_ha.sa_family = dev->type;
1070 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1071 err = 0;
1072 }
1073 neigh_release(neigh);
1074 }
1075 return err;
1076}
1077
1078static int arp_invalidate(struct net_device *dev, __be32 ip)
1079{
1080 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1081 int err = -ENXIO;
1082
1083 if (neigh) {
1084 if (neigh->nud_state & ~NUD_NOARP)
1085 err = neigh_update(neigh, NULL, NUD_FAILED,
1086 NEIGH_UPDATE_F_OVERRIDE|
1087 NEIGH_UPDATE_F_ADMIN);
1088 neigh_release(neigh);
1089 }
1090
1091 return err;
1092}
1093
1094static int arp_req_delete_public(struct net *net, struct arpreq *r,
1095 struct net_device *dev)
1096{
1097 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1098 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1099
1100 if (mask == htonl(0xFFFFFFFF))
1101 return pneigh_delete(&arp_tbl, net, &ip, dev);
1102
1103 if (mask)
1104 return -EINVAL;
1105
1106 return arp_req_set_proxy(net, dev, 0);
1107}
1108
1109static int arp_req_delete(struct net *net, struct arpreq *r,
1110 struct net_device *dev)
1111{
1112 __be32 ip;
1113
1114 if (r->arp_flags & ATF_PUBL)
1115 return arp_req_delete_public(net, r, dev);
1116
1117 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1118 if (!dev) {
1119 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1120 if (IS_ERR(rt))
1121 return PTR_ERR(rt);
1122 dev = rt->dst.dev;
1123 ip_rt_put(rt);
1124 if (!dev)
1125 return -EINVAL;
1126 }
1127 return arp_invalidate(dev, ip);
1128}
1129
1130/*
1131 * Handle an ARP layer I/O control request.
1132 */
1133
1134int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1135{
1136 int err;
1137 struct arpreq r;
1138 struct net_device *dev = NULL;
1139
1140 switch (cmd) {
1141 case SIOCDARP:
1142 case SIOCSARP:
1143 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1144 return -EPERM;
1145 case SIOCGARP:
1146 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1147 if (err)
1148 return -EFAULT;
1149 break;
1150 default:
1151 return -EINVAL;
1152 }
1153
1154 if (r.arp_pa.sa_family != AF_INET)
1155 return -EPFNOSUPPORT;
1156
1157 if (!(r.arp_flags & ATF_PUBL) &&
1158 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1159 return -EINVAL;
1160 if (!(r.arp_flags & ATF_NETMASK))
1161 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1162 htonl(0xFFFFFFFFUL);
1163 rtnl_lock();
1164 if (r.arp_dev[0]) {
1165 err = -ENODEV;
1166 dev = __dev_get_by_name(net, r.arp_dev);
1167 if (!dev)
1168 goto out;
1169
1170 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1171 if (!r.arp_ha.sa_family)
1172 r.arp_ha.sa_family = dev->type;
1173 err = -EINVAL;
1174 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1175 goto out;
1176 } else if (cmd == SIOCGARP) {
1177 err = -ENODEV;
1178 goto out;
1179 }
1180
1181 switch (cmd) {
1182 case SIOCDARP:
1183 err = arp_req_delete(net, &r, dev);
1184 break;
1185 case SIOCSARP:
1186 err = arp_req_set(net, &r, dev);
1187 break;
1188 case SIOCGARP:
1189 err = arp_req_get(&r, dev);
1190 break;
1191 }
1192out:
1193 rtnl_unlock();
1194 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1195 err = -EFAULT;
1196 return err;
1197}
1198
1199static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1200 void *ptr)
1201{
1202 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1203 struct netdev_notifier_change_info *change_info;
1204
1205 switch (event) {
1206 case NETDEV_CHANGEADDR:
1207 neigh_changeaddr(&arp_tbl, dev);
1208 rt_cache_flush(dev_net(dev));
1209 break;
1210 case NETDEV_CHANGE:
1211 change_info = ptr;
1212 if (change_info->flags_changed & IFF_NOARP)
1213 neigh_changeaddr(&arp_tbl, dev);
1214 break;
1215 default:
1216 break;
1217 }
1218
1219 return NOTIFY_DONE;
1220}
1221
1222static struct notifier_block arp_netdev_notifier = {
1223 .notifier_call = arp_netdev_event,
1224};
1225
1226/* Note, that it is not on notifier chain.
1227 It is necessary, that this routine was called after route cache will be
1228 flushed.
1229 */
1230void arp_ifdown(struct net_device *dev)
1231{
1232 neigh_ifdown(&arp_tbl, dev);
1233}
1234
1235
1236/*
1237 * Called once on startup.
1238 */
1239
1240static struct packet_type arp_packet_type __read_mostly = {
1241 .type = cpu_to_be16(ETH_P_ARP),
1242 .func = arp_rcv,
1243};
1244
1245static int arp_proc_init(void);
1246
1247void __init arp_init(void)
1248{
1249 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
1250
1251 dev_add_pack(&arp_packet_type);
1252 arp_proc_init();
1253#ifdef CONFIG_SYSCTL
1254 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1255#endif
1256 register_netdevice_notifier(&arp_netdev_notifier);
1257}
1258
1259#ifdef CONFIG_PROC_FS
1260#if IS_ENABLED(CONFIG_AX25)
1261
1262/* ------------------------------------------------------------------------ */
1263/*
1264 * ax25 -> ASCII conversion
1265 */
1266static char *ax2asc2(ax25_address *a, char *buf)
1267{
1268 char c, *s;
1269 int n;
1270
1271 for (n = 0, s = buf; n < 6; n++) {
1272 c = (a->ax25_call[n] >> 1) & 0x7F;
1273
1274 if (c != ' ')
1275 *s++ = c;
1276 }
1277
1278 *s++ = '-';
1279 n = (a->ax25_call[6] >> 1) & 0x0F;
1280 if (n > 9) {
1281 *s++ = '1';
1282 n -= 10;
1283 }
1284
1285 *s++ = n + '0';
1286 *s++ = '\0';
1287
1288 if (*buf == '\0' || *buf == '-')
1289 return "*";
1290
1291 return buf;
1292}
1293#endif /* CONFIG_AX25 */
1294
1295#define HBUFFERLEN 30
1296
1297static void arp_format_neigh_entry(struct seq_file *seq,
1298 struct neighbour *n)
1299{
1300 char hbuffer[HBUFFERLEN];
1301 int k, j;
1302 char tbuf[16];
1303 struct net_device *dev = n->dev;
1304 int hatype = dev->type;
1305
1306 read_lock(&n->lock);
1307 /* Convert hardware address to XX:XX:XX:XX ... form. */
1308#if IS_ENABLED(CONFIG_AX25)
1309 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1310 ax2asc2((ax25_address *)n->ha, hbuffer);
1311 else {
1312#endif
1313 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1314 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1315 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1316 hbuffer[k++] = ':';
1317 }
1318 if (k != 0)
1319 --k;
1320 hbuffer[k] = 0;
1321#if IS_ENABLED(CONFIG_AX25)
1322 }
1323#endif
1324 sprintf(tbuf, "%pI4", n->primary_key);
1325 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1326 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1327 read_unlock(&n->lock);
1328}
1329
1330static void arp_format_pneigh_entry(struct seq_file *seq,
1331 struct pneigh_entry *n)
1332{
1333 struct net_device *dev = n->dev;
1334 int hatype = dev ? dev->type : 0;
1335 char tbuf[16];
1336
1337 sprintf(tbuf, "%pI4", n->key);
1338 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1339 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1340 dev ? dev->name : "*");
1341}
1342
1343static int arp_seq_show(struct seq_file *seq, void *v)
1344{
1345 if (v == SEQ_START_TOKEN) {
1346 seq_puts(seq, "IP address HW type Flags "
1347 "HW address Mask Device\n");
1348 } else {
1349 struct neigh_seq_state *state = seq->private;
1350
1351 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1352 arp_format_pneigh_entry(seq, v);
1353 else
1354 arp_format_neigh_entry(seq, v);
1355 }
1356
1357 return 0;
1358}
1359
1360static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1361{
1362 /* Don't want to confuse "arp -a" w/ magic entries,
1363 * so we tell the generic iterator to skip NUD_NOARP.
1364 */
1365 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1366}
1367
1368/* ------------------------------------------------------------------------ */
1369
1370static const struct seq_operations arp_seq_ops = {
1371 .start = arp_seq_start,
1372 .next = neigh_seq_next,
1373 .stop = neigh_seq_stop,
1374 .show = arp_seq_show,
1375};
1376
1377static int arp_seq_open(struct inode *inode, struct file *file)
1378{
1379 return seq_open_net(inode, file, &arp_seq_ops,
1380 sizeof(struct neigh_seq_state));
1381}
1382
1383static const struct file_operations arp_seq_fops = {
1384 .owner = THIS_MODULE,
1385 .open = arp_seq_open,
1386 .read = seq_read,
1387 .llseek = seq_lseek,
1388 .release = seq_release_net,
1389};
1390
1391
1392static int __net_init arp_net_init(struct net *net)
1393{
1394 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops))
1395 return -ENOMEM;
1396 return 0;
1397}
1398
1399static void __net_exit arp_net_exit(struct net *net)
1400{
1401 remove_proc_entry("arp", net->proc_net);
1402}
1403
1404static struct pernet_operations arp_net_ops = {
1405 .init = arp_net_init,
1406 .exit = arp_net_exit,
1407};
1408
1409static int __init arp_proc_init(void)
1410{
1411 return register_pernet_subsys(&arp_net_ops);
1412}
1413
1414#else /* CONFIG_PROC_FS */
1415
1416static int __init arp_proc_init(void)
1417{
1418 return 0;
1419}
1420
1421#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 */