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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// SPDX-License-Identifier: GPL-2.0-or-later
2/* linux/net/ipv4/arp.c
3 *
4 * Copyright (C) 1994 by Florian La Roche
5 *
6 * This module implements the Address Resolution Protocol ARP (RFC 826),
7 * which is used to convert IP addresses (or in the future maybe other
8 * high-level addresses) into a low-level hardware address (like an Ethernet
9 * address).
10 *
11 * Fixes:
12 * Alan Cox : Removed the Ethernet assumptions in
13 * Florian's code
14 * Alan Cox : Fixed some small errors in the ARP
15 * logic
16 * Alan Cox : Allow >4K in /proc
17 * Alan Cox : Make ARP add its own protocol entry
18 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
19 * Stephen Henson : Add AX25 support to arp_get_info()
20 * Alan Cox : Drop data when a device is downed.
21 * Alan Cox : Use init_timer().
22 * Alan Cox : Double lock fixes.
23 * Martin Seine : Move the arphdr structure
24 * to if_arp.h for compatibility.
25 * with BSD based programs.
26 * Andrew Tridgell : Added ARP netmask code and
27 * re-arranged proxy handling.
28 * Alan Cox : Changed to use notifiers.
29 * Niibe Yutaka : Reply for this device or proxies only.
30 * Alan Cox : Don't proxy across hardware types!
31 * Jonathan Naylor : Added support for NET/ROM.
32 * Mike Shaver : RFC1122 checks.
33 * Jonathan Naylor : Only lookup the hardware address for
34 * the correct hardware type.
35 * Germano Caronni : Assorted subtle races.
36 * Craig Schlenter : Don't modify permanent entry
37 * during arp_rcv.
38 * Russ Nelson : Tidied up a few bits.
39 * Alexey Kuznetsov: Major changes to caching and behaviour,
40 * eg intelligent arp probing and
41 * generation
42 * of host down events.
43 * Alan Cox : Missing unlock in device events.
44 * Eckes : ARP ioctl control errors.
45 * Alexey Kuznetsov: Arp free fix.
46 * Manuel Rodriguez: Gratuitous ARP.
47 * Jonathan Layes : Added arpd support through kerneld
48 * message queue (960314)
49 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
50 * Mike McLagan : Routing by source
51 * Stuart Cheshire : Metricom and grat arp fixes
52 * *** FOR 2.1 clean this up ***
53 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
54 * Alan Cox : Took the AP1000 nasty FDDI hack and
55 * folded into the mainstream FDDI code.
56 * Ack spit, Linus how did you allow that
57 * one in...
58 * Jes Sorensen : Make FDDI work again in 2.1.x and
59 * clean up the APFDDI & gen. FDDI bits.
60 * Alexey Kuznetsov: new arp state machine;
61 * now it is in net/core/neighbour.c.
62 * Krzysztof Halasa: Added Frame Relay ARP support.
63 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
64 * Shmulik Hen: Split arp_send to arp_create and
65 * arp_xmit so intermediate drivers like
66 * bonding can change the skb before
67 * sending (e.g. insert 8021q tag).
68 * Harald Welte : convert to make use of jenkins hash
69 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
70 */
71
72#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
73
74#include <linux/module.h>
75#include <linux/types.h>
76#include <linux/string.h>
77#include <linux/kernel.h>
78#include <linux/capability.h>
79#include <linux/socket.h>
80#include <linux/sockios.h>
81#include <linux/errno.h>
82#include <linux/in.h>
83#include <linux/mm.h>
84#include <linux/inet.h>
85#include <linux/inetdevice.h>
86#include <linux/netdevice.h>
87#include <linux/etherdevice.h>
88#include <linux/fddidevice.h>
89#include <linux/if_arp.h>
90#include <linux/skbuff.h>
91#include <linux/proc_fs.h>
92#include <linux/seq_file.h>
93#include <linux/stat.h>
94#include <linux/init.h>
95#include <linux/net.h>
96#include <linux/rcupdate.h>
97#include <linux/slab.h>
98#ifdef CONFIG_SYSCTL
99#include <linux/sysctl.h>
100#endif
101
102#include <net/net_namespace.h>
103#include <net/ip.h>
104#include <net/icmp.h>
105#include <net/route.h>
106#include <net/protocol.h>
107#include <net/tcp.h>
108#include <net/sock.h>
109#include <net/arp.h>
110#include <net/ax25.h>
111#include <net/netrom.h>
112#include <net/dst_metadata.h>
113#include <net/ip_tunnels.h>
114
115#include <linux/uaccess.h>
116
117#include <linux/netfilter_arp.h>
118
119/*
120 * Interface to generic neighbour cache.
121 */
122static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
123static bool arp_key_eq(const struct neighbour *n, const void *pkey);
124static int arp_constructor(struct neighbour *neigh);
125static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
126static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
127static void parp_redo(struct sk_buff *skb);
128
129static const struct neigh_ops arp_generic_ops = {
130 .family = AF_INET,
131 .solicit = arp_solicit,
132 .error_report = arp_error_report,
133 .output = neigh_resolve_output,
134 .connected_output = neigh_connected_output,
135};
136
137static const struct neigh_ops arp_hh_ops = {
138 .family = AF_INET,
139 .solicit = arp_solicit,
140 .error_report = arp_error_report,
141 .output = neigh_resolve_output,
142 .connected_output = neigh_resolve_output,
143};
144
145static const struct neigh_ops arp_direct_ops = {
146 .family = AF_INET,
147 .output = neigh_direct_output,
148 .connected_output = neigh_direct_output,
149};
150
151struct neigh_table arp_tbl = {
152 .family = AF_INET,
153 .key_len = 4,
154 .protocol = cpu_to_be16(ETH_P_IP),
155 .hash = arp_hash,
156 .key_eq = arp_key_eq,
157 .constructor = arp_constructor,
158 .proxy_redo = parp_redo,
159 .id = "arp_cache",
160 .parms = {
161 .tbl = &arp_tbl,
162 .reachable_time = 30 * HZ,
163 .data = {
164 [NEIGH_VAR_MCAST_PROBES] = 3,
165 [NEIGH_VAR_UCAST_PROBES] = 3,
166 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
167 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
168 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
169 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
170 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
171 [NEIGH_VAR_PROXY_QLEN] = 64,
172 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
173 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
174 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
175 },
176 },
177 .gc_interval = 30 * HZ,
178 .gc_thresh1 = 128,
179 .gc_thresh2 = 512,
180 .gc_thresh3 = 1024,
181};
182EXPORT_SYMBOL(arp_tbl);
183
184int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
185{
186 switch (dev->type) {
187 case ARPHRD_ETHER:
188 case ARPHRD_FDDI:
189 case ARPHRD_IEEE802:
190 ip_eth_mc_map(addr, haddr);
191 return 0;
192 case ARPHRD_INFINIBAND:
193 ip_ib_mc_map(addr, dev->broadcast, haddr);
194 return 0;
195 case ARPHRD_IPGRE:
196 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
197 return 0;
198 default:
199 if (dir) {
200 memcpy(haddr, dev->broadcast, dev->addr_len);
201 return 0;
202 }
203 }
204 return -EINVAL;
205}
206
207
208static u32 arp_hash(const void *pkey,
209 const struct net_device *dev,
210 __u32 *hash_rnd)
211{
212 return arp_hashfn(pkey, dev, hash_rnd);
213}
214
215static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
216{
217 return neigh_key_eq32(neigh, pkey);
218}
219
220static int arp_constructor(struct neighbour *neigh)
221{
222 __be32 addr;
223 struct net_device *dev = neigh->dev;
224 struct in_device *in_dev;
225 struct neigh_parms *parms;
226 u32 inaddr_any = INADDR_ANY;
227
228 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
229 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len);
230
231 addr = *(__be32 *)neigh->primary_key;
232 rcu_read_lock();
233 in_dev = __in_dev_get_rcu(dev);
234 if (!in_dev) {
235 rcu_read_unlock();
236 return -EINVAL;
237 }
238
239 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
240
241 parms = in_dev->arp_parms;
242 __neigh_parms_put(neigh->parms);
243 neigh->parms = neigh_parms_clone(parms);
244 rcu_read_unlock();
245
246 if (!dev->header_ops) {
247 neigh->nud_state = NUD_NOARP;
248 neigh->ops = &arp_direct_ops;
249 neigh->output = neigh_direct_output;
250 } else {
251 /* Good devices (checked by reading texts, but only Ethernet is
252 tested)
253
254 ARPHRD_ETHER: (ethernet, apfddi)
255 ARPHRD_FDDI: (fddi)
256 ARPHRD_IEEE802: (tr)
257 ARPHRD_METRICOM: (strip)
258 ARPHRD_ARCNET:
259 etc. etc. etc.
260
261 ARPHRD_IPDDP will also work, if author repairs it.
262 I did not it, because this driver does not work even
263 in old paradigm.
264 */
265
266 if (neigh->type == RTN_MULTICAST) {
267 neigh->nud_state = NUD_NOARP;
268 arp_mc_map(addr, neigh->ha, dev, 1);
269 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
270 neigh->nud_state = NUD_NOARP;
271 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
272 } else if (neigh->type == RTN_BROADCAST ||
273 (dev->flags & IFF_POINTOPOINT)) {
274 neigh->nud_state = NUD_NOARP;
275 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
276 }
277
278 if (dev->header_ops->cache)
279 neigh->ops = &arp_hh_ops;
280 else
281 neigh->ops = &arp_generic_ops;
282
283 if (neigh->nud_state & NUD_VALID)
284 neigh->output = neigh->ops->connected_output;
285 else
286 neigh->output = neigh->ops->output;
287 }
288 return 0;
289}
290
291static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
292{
293 dst_link_failure(skb);
294 kfree_skb(skb);
295}
296
297/* Create and send an arp packet. */
298static void arp_send_dst(int type, int ptype, __be32 dest_ip,
299 struct net_device *dev, __be32 src_ip,
300 const unsigned char *dest_hw,
301 const unsigned char *src_hw,
302 const unsigned char *target_hw,
303 struct dst_entry *dst)
304{
305 struct sk_buff *skb;
306
307 /* arp on this interface. */
308 if (dev->flags & IFF_NOARP)
309 return;
310
311 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
312 dest_hw, src_hw, target_hw);
313 if (!skb)
314 return;
315
316 skb_dst_set(skb, dst_clone(dst));
317 arp_xmit(skb);
318}
319
320void arp_send(int type, int ptype, __be32 dest_ip,
321 struct net_device *dev, __be32 src_ip,
322 const unsigned char *dest_hw, const unsigned char *src_hw,
323 const unsigned char *target_hw)
324{
325 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
326 target_hw, NULL);
327}
328EXPORT_SYMBOL(arp_send);
329
330static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
331{
332 __be32 saddr = 0;
333 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = 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 struct dst_entry *dst = NULL;
339
340 rcu_read_lock();
341 in_dev = __in_dev_get_rcu(dev);
342 if (!in_dev) {
343 rcu_read_unlock();
344 return;
345 }
346 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
347 default:
348 case 0: /* By default announce any local IP */
349 if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
350 ip_hdr(skb)->saddr) == RTN_LOCAL)
351 saddr = ip_hdr(skb)->saddr;
352 break;
353 case 1: /* Restrict announcements of saddr in same subnet */
354 if (!skb)
355 break;
356 saddr = ip_hdr(skb)->saddr;
357 if (inet_addr_type_dev_table(dev_net(dev), dev,
358 saddr) == RTN_LOCAL) {
359 /* saddr should be known to target */
360 if (inet_addr_onlink(in_dev, target, saddr))
361 break;
362 }
363 saddr = 0;
364 break;
365 case 2: /* Avoid secondary IPs, get a primary/preferred one */
366 break;
367 }
368 rcu_read_unlock();
369
370 if (!saddr)
371 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
372
373 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
374 if (probes < 0) {
375 if (!(neigh->nud_state & NUD_VALID))
376 pr_debug("trying to ucast probe in NUD_INVALID\n");
377 neigh_ha_snapshot(dst_ha, neigh, dev);
378 dst_hw = dst_ha;
379 } else {
380 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
381 if (probes < 0) {
382 neigh_app_ns(neigh);
383 return;
384 }
385 }
386
387 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
388 dst = skb_dst(skb);
389 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
390 dst_hw, dev->dev_addr, NULL, dst);
391}
392
393static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
394{
395 struct net *net = dev_net(in_dev->dev);
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 in_dev = NULL;
415 break;
416 case 4: /* Reserved */
417 case 5:
418 case 6:
419 case 7:
420 return 0;
421 case 8: /* Do not reply */
422 return 1;
423 default:
424 return 0;
425 }
426 return !inet_confirm_addr(net, in_dev, sip, tip, scope);
427}
428
429static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
430{
431 struct rtable *rt;
432 int flag = 0;
433 /*unsigned long now; */
434 struct net *net = dev_net(dev);
435
436 rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev));
437 if (IS_ERR(rt))
438 return 1;
439 if (rt->dst.dev != dev) {
440 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER);
441 flag = 1;
442 }
443 ip_rt_put(rt);
444 return flag;
445}
446
447/*
448 * Check if we can use proxy ARP for this path
449 */
450static inline int arp_fwd_proxy(struct in_device *in_dev,
451 struct net_device *dev, struct rtable *rt)
452{
453 struct in_device *out_dev;
454 int imi, omi = -1;
455
456 if (rt->dst.dev == dev)
457 return 0;
458
459 if (!IN_DEV_PROXY_ARP(in_dev))
460 return 0;
461 imi = IN_DEV_MEDIUM_ID(in_dev);
462 if (imi == 0)
463 return 1;
464 if (imi == -1)
465 return 0;
466
467 /* place to check for proxy_arp for routes */
468
469 out_dev = __in_dev_get_rcu(rt->dst.dev);
470 if (out_dev)
471 omi = IN_DEV_MEDIUM_ID(out_dev);
472
473 return omi != imi && omi != -1;
474}
475
476/*
477 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
478 *
479 * RFC3069 supports proxy arp replies back to the same interface. This
480 * is done to support (ethernet) switch features, like RFC 3069, where
481 * the individual ports are not allowed to communicate with each
482 * other, BUT they are allowed to talk to the upstream router. As
483 * described in RFC 3069, it is possible to allow these hosts to
484 * communicate through the upstream router, by proxy_arp'ing.
485 *
486 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
487 *
488 * This technology is known by different names:
489 * In RFC 3069 it is called VLAN Aggregation.
490 * Cisco and Allied Telesyn call it Private VLAN.
491 * Hewlett-Packard call it Source-Port filtering or port-isolation.
492 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
493 *
494 */
495static inline int arp_fwd_pvlan(struct in_device *in_dev,
496 struct net_device *dev, struct rtable *rt,
497 __be32 sip, __be32 tip)
498{
499 /* Private VLAN is only concerned about the same ethernet segment */
500 if (rt->dst.dev != dev)
501 return 0;
502
503 /* Don't reply on self probes (often done by windowz boxes)*/
504 if (sip == tip)
505 return 0;
506
507 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
508 return 1;
509 else
510 return 0;
511}
512
513/*
514 * Interface to link layer: send routine and receive handler.
515 */
516
517/*
518 * Create an arp packet. If dest_hw is not set, we create a broadcast
519 * message.
520 */
521struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
522 struct net_device *dev, __be32 src_ip,
523 const unsigned char *dest_hw,
524 const unsigned char *src_hw,
525 const unsigned char *target_hw)
526{
527 struct sk_buff *skb;
528 struct arphdr *arp;
529 unsigned char *arp_ptr;
530 int hlen = LL_RESERVED_SPACE(dev);
531 int tlen = dev->needed_tailroom;
532
533 /*
534 * Allocate a buffer
535 */
536
537 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
538 if (!skb)
539 return NULL;
540
541 skb_reserve(skb, hlen);
542 skb_reset_network_header(skb);
543 arp = skb_put(skb, arp_hdr_len(dev));
544 skb->dev = dev;
545 skb->protocol = htons(ETH_P_ARP);
546 if (!src_hw)
547 src_hw = dev->dev_addr;
548 if (!dest_hw)
549 dest_hw = dev->broadcast;
550
551 /*
552 * Fill the device header for the ARP frame
553 */
554 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
555 goto out;
556
557 /*
558 * Fill out the arp protocol part.
559 *
560 * The arp hardware type should match the device type, except for FDDI,
561 * which (according to RFC 1390) should always equal 1 (Ethernet).
562 */
563 /*
564 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
565 * DIX code for the protocol. Make these device structure fields.
566 */
567 switch (dev->type) {
568 default:
569 arp->ar_hrd = htons(dev->type);
570 arp->ar_pro = htons(ETH_P_IP);
571 break;
572
573#if IS_ENABLED(CONFIG_AX25)
574 case ARPHRD_AX25:
575 arp->ar_hrd = htons(ARPHRD_AX25);
576 arp->ar_pro = htons(AX25_P_IP);
577 break;
578
579#if IS_ENABLED(CONFIG_NETROM)
580 case ARPHRD_NETROM:
581 arp->ar_hrd = htons(ARPHRD_NETROM);
582 arp->ar_pro = htons(AX25_P_IP);
583 break;
584#endif
585#endif
586
587#if IS_ENABLED(CONFIG_FDDI)
588 case ARPHRD_FDDI:
589 arp->ar_hrd = htons(ARPHRD_ETHER);
590 arp->ar_pro = htons(ETH_P_IP);
591 break;
592#endif
593 }
594
595 arp->ar_hln = dev->addr_len;
596 arp->ar_pln = 4;
597 arp->ar_op = htons(type);
598
599 arp_ptr = (unsigned char *)(arp + 1);
600
601 memcpy(arp_ptr, src_hw, dev->addr_len);
602 arp_ptr += dev->addr_len;
603 memcpy(arp_ptr, &src_ip, 4);
604 arp_ptr += 4;
605
606 switch (dev->type) {
607#if IS_ENABLED(CONFIG_FIREWIRE_NET)
608 case ARPHRD_IEEE1394:
609 break;
610#endif
611 default:
612 if (target_hw)
613 memcpy(arp_ptr, target_hw, dev->addr_len);
614 else
615 memset(arp_ptr, 0, dev->addr_len);
616 arp_ptr += dev->addr_len;
617 }
618 memcpy(arp_ptr, &dest_ip, 4);
619
620 return skb;
621
622out:
623 kfree_skb(skb);
624 return NULL;
625}
626EXPORT_SYMBOL(arp_create);
627
628static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
629{
630 return dev_queue_xmit(skb);
631}
632
633/*
634 * Send an arp packet.
635 */
636void arp_xmit(struct sk_buff *skb)
637{
638 /* Send it off, maybe filter it using firewalling first. */
639 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
640 dev_net(skb->dev), NULL, skb, NULL, skb->dev,
641 arp_xmit_finish);
642}
643EXPORT_SYMBOL(arp_xmit);
644
645static bool arp_is_garp(struct net *net, struct net_device *dev,
646 int *addr_type, __be16 ar_op,
647 __be32 sip, __be32 tip,
648 unsigned char *sha, unsigned char *tha)
649{
650 bool is_garp = tip == sip;
651
652 /* Gratuitous ARP _replies_ also require target hwaddr to be
653 * the same as source.
654 */
655 if (is_garp && ar_op == htons(ARPOP_REPLY))
656 is_garp =
657 /* IPv4 over IEEE 1394 doesn't provide target
658 * hardware address field in its ARP payload.
659 */
660 tha &&
661 !memcmp(tha, sha, dev->addr_len);
662
663 if (is_garp) {
664 *addr_type = inet_addr_type_dev_table(net, dev, sip);
665 if (*addr_type != RTN_UNICAST)
666 is_garp = false;
667 }
668 return is_garp;
669}
670
671/*
672 * Process an arp request.
673 */
674
675static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
676{
677 struct net_device *dev = skb->dev;
678 struct in_device *in_dev = __in_dev_get_rcu(dev);
679 struct arphdr *arp;
680 unsigned char *arp_ptr;
681 struct rtable *rt;
682 unsigned char *sha;
683 unsigned char *tha = NULL;
684 __be32 sip, tip;
685 u16 dev_type = dev->type;
686 int addr_type;
687 struct neighbour *n;
688 struct dst_entry *reply_dst = NULL;
689 bool is_garp = false;
690
691 /* arp_rcv below verifies the ARP header and verifies the device
692 * is ARP'able.
693 */
694
695 if (!in_dev)
696 goto out_free_skb;
697
698 arp = arp_hdr(skb);
699
700 switch (dev_type) {
701 default:
702 if (arp->ar_pro != htons(ETH_P_IP) ||
703 htons(dev_type) != arp->ar_hrd)
704 goto out_free_skb;
705 break;
706 case ARPHRD_ETHER:
707 case ARPHRD_FDDI:
708 case ARPHRD_IEEE802:
709 /*
710 * ETHERNET, and Fibre Channel (which are IEEE 802
711 * devices, according to RFC 2625) devices will accept ARP
712 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
713 * This is the case also of FDDI, where the RFC 1390 says that
714 * FDDI devices should accept ARP hardware of (1) Ethernet,
715 * however, to be more robust, we'll accept both 1 (Ethernet)
716 * or 6 (IEEE 802.2)
717 */
718 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
719 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
720 arp->ar_pro != htons(ETH_P_IP))
721 goto out_free_skb;
722 break;
723 case ARPHRD_AX25:
724 if (arp->ar_pro != htons(AX25_P_IP) ||
725 arp->ar_hrd != htons(ARPHRD_AX25))
726 goto out_free_skb;
727 break;
728 case ARPHRD_NETROM:
729 if (arp->ar_pro != htons(AX25_P_IP) ||
730 arp->ar_hrd != htons(ARPHRD_NETROM))
731 goto out_free_skb;
732 break;
733 }
734
735 /* Understand only these message types */
736
737 if (arp->ar_op != htons(ARPOP_REPLY) &&
738 arp->ar_op != htons(ARPOP_REQUEST))
739 goto out_free_skb;
740
741/*
742 * Extract fields
743 */
744 arp_ptr = (unsigned char *)(arp + 1);
745 sha = arp_ptr;
746 arp_ptr += dev->addr_len;
747 memcpy(&sip, arp_ptr, 4);
748 arp_ptr += 4;
749 switch (dev_type) {
750#if IS_ENABLED(CONFIG_FIREWIRE_NET)
751 case ARPHRD_IEEE1394:
752 break;
753#endif
754 default:
755 tha = arp_ptr;
756 arp_ptr += dev->addr_len;
757 }
758 memcpy(&tip, arp_ptr, 4);
759/*
760 * Check for bad requests for 127.x.x.x and requests for multicast
761 * addresses. If this is one such, delete it.
762 */
763 if (ipv4_is_multicast(tip) ||
764 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
765 goto out_free_skb;
766
767 /*
768 * For some 802.11 wireless deployments (and possibly other networks),
769 * there will be an ARP proxy and gratuitous ARP frames are attacks
770 * and thus should not be accepted.
771 */
772 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
773 goto out_free_skb;
774
775/*
776 * Special case: We must set Frame Relay source Q.922 address
777 */
778 if (dev_type == ARPHRD_DLCI)
779 sha = dev->broadcast;
780
781/*
782 * Process entry. The idea here is we want to send a reply if it is a
783 * request for us or if it is a request for someone else that we hold
784 * a proxy for. We want to add an entry to our cache if it is a reply
785 * to us or if it is a request for our address.
786 * (The assumption for this last is that if someone is requesting our
787 * address, they are probably intending to talk to us, so it saves time
788 * if we cache their address. Their address is also probably not in
789 * our cache, since ours is not in their cache.)
790 *
791 * Putting this another way, we only care about replies if they are to
792 * us, in which case we add them to the cache. For requests, we care
793 * about those for us and those for our proxies. We reply to both,
794 * and in the case of requests for us we add the requester to the arp
795 * cache.
796 */
797
798 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
799 reply_dst = (struct dst_entry *)
800 iptunnel_metadata_reply(skb_metadata_dst(skb),
801 GFP_ATOMIC);
802
803 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
804 if (sip == 0) {
805 if (arp->ar_op == htons(ARPOP_REQUEST) &&
806 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
807 !arp_ignore(in_dev, sip, tip))
808 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
809 sha, dev->dev_addr, sha, reply_dst);
810 goto out_consume_skb;
811 }
812
813 if (arp->ar_op == htons(ARPOP_REQUEST) &&
814 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
815
816 rt = skb_rtable(skb);
817 addr_type = rt->rt_type;
818
819 if (addr_type == RTN_LOCAL) {
820 int dont_send;
821
822 dont_send = arp_ignore(in_dev, sip, tip);
823 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
824 dont_send = arp_filter(sip, tip, dev);
825 if (!dont_send) {
826 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
827 if (n) {
828 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
829 sip, dev, tip, sha,
830 dev->dev_addr, sha,
831 reply_dst);
832 neigh_release(n);
833 }
834 }
835 goto out_consume_skb;
836 } else if (IN_DEV_FORWARD(in_dev)) {
837 if (addr_type == RTN_UNICAST &&
838 (arp_fwd_proxy(in_dev, dev, rt) ||
839 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
840 (rt->dst.dev != dev &&
841 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
842 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
843 if (n)
844 neigh_release(n);
845
846 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
847 skb->pkt_type == PACKET_HOST ||
848 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
849 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
850 sip, dev, tip, sha,
851 dev->dev_addr, sha,
852 reply_dst);
853 } else {
854 pneigh_enqueue(&arp_tbl,
855 in_dev->arp_parms, skb);
856 goto out_free_dst;
857 }
858 goto out_consume_skb;
859 }
860 }
861 }
862
863 /* Update our ARP tables */
864
865 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
866
867 addr_type = -1;
868 if (n || IN_DEV_ARP_ACCEPT(in_dev)) {
869 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op,
870 sip, tip, sha, tha);
871 }
872
873 if (IN_DEV_ARP_ACCEPT(in_dev)) {
874 /* Unsolicited ARP is not accepted by default.
875 It is possible, that this option should be enabled for some
876 devices (strip is candidate)
877 */
878 if (!n &&
879 (is_garp ||
880 (arp->ar_op == htons(ARPOP_REPLY) &&
881 (addr_type == RTN_UNICAST ||
882 (addr_type < 0 &&
883 /* postpone calculation to as late as possible */
884 inet_addr_type_dev_table(net, dev, sip) ==
885 RTN_UNICAST)))))
886 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
887 }
888
889 if (n) {
890 int state = NUD_REACHABLE;
891 int override;
892
893 /* If several different ARP replies follows back-to-back,
894 use the FIRST one. It is possible, if several proxy
895 agents are active. Taking the first reply prevents
896 arp trashing and chooses the fastest router.
897 */
898 override = time_after(jiffies,
899 n->updated +
900 NEIGH_VAR(n->parms, LOCKTIME)) ||
901 is_garp;
902
903 /* Broadcast replies and request packets
904 do not assert neighbour reachability.
905 */
906 if (arp->ar_op != htons(ARPOP_REPLY) ||
907 skb->pkt_type != PACKET_HOST)
908 state = NUD_STALE;
909 neigh_update(n, sha, state,
910 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0);
911 neigh_release(n);
912 }
913
914out_consume_skb:
915 consume_skb(skb);
916
917out_free_dst:
918 dst_release(reply_dst);
919 return NET_RX_SUCCESS;
920
921out_free_skb:
922 kfree_skb(skb);
923 return NET_RX_DROP;
924}
925
926static void parp_redo(struct sk_buff *skb)
927{
928 arp_process(dev_net(skb->dev), NULL, skb);
929}
930
931
932/*
933 * Receive an arp request from the device layer.
934 */
935
936static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
937 struct packet_type *pt, struct net_device *orig_dev)
938{
939 const struct arphdr *arp;
940
941 /* do not tweak dropwatch on an ARP we will ignore */
942 if (dev->flags & IFF_NOARP ||
943 skb->pkt_type == PACKET_OTHERHOST ||
944 skb->pkt_type == PACKET_LOOPBACK)
945 goto consumeskb;
946
947 skb = skb_share_check(skb, GFP_ATOMIC);
948 if (!skb)
949 goto out_of_mem;
950
951 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
952 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
953 goto freeskb;
954
955 arp = arp_hdr(skb);
956 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
957 goto freeskb;
958
959 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
960
961 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
962 dev_net(dev), NULL, skb, dev, NULL,
963 arp_process);
964
965consumeskb:
966 consume_skb(skb);
967 return NET_RX_SUCCESS;
968freeskb:
969 kfree_skb(skb);
970out_of_mem:
971 return NET_RX_DROP;
972}
973
974/*
975 * User level interface (ioctl)
976 */
977
978/*
979 * Set (create) an ARP cache entry.
980 */
981
982static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
983{
984 if (!dev) {
985 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
986 return 0;
987 }
988 if (__in_dev_get_rtnl(dev)) {
989 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
990 return 0;
991 }
992 return -ENXIO;
993}
994
995static int arp_req_set_public(struct net *net, struct arpreq *r,
996 struct net_device *dev)
997{
998 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
999 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1000
1001 if (mask && mask != htonl(0xFFFFFFFF))
1002 return -EINVAL;
1003 if (!dev && (r->arp_flags & ATF_COM)) {
1004 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1005 r->arp_ha.sa_data);
1006 if (!dev)
1007 return -ENODEV;
1008 }
1009 if (mask) {
1010 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
1011 return -ENOBUFS;
1012 return 0;
1013 }
1014
1015 return arp_req_set_proxy(net, dev, 1);
1016}
1017
1018static int arp_req_set(struct net *net, struct arpreq *r,
1019 struct net_device *dev)
1020{
1021 __be32 ip;
1022 struct neighbour *neigh;
1023 int err;
1024
1025 if (r->arp_flags & ATF_PUBL)
1026 return arp_req_set_public(net, r, dev);
1027
1028 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1029 if (r->arp_flags & ATF_PERM)
1030 r->arp_flags |= ATF_COM;
1031 if (!dev) {
1032 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1033
1034 if (IS_ERR(rt))
1035 return PTR_ERR(rt);
1036 dev = rt->dst.dev;
1037 ip_rt_put(rt);
1038 if (!dev)
1039 return -EINVAL;
1040 }
1041 switch (dev->type) {
1042#if IS_ENABLED(CONFIG_FDDI)
1043 case ARPHRD_FDDI:
1044 /*
1045 * According to RFC 1390, FDDI devices should accept ARP
1046 * hardware types of 1 (Ethernet). However, to be more
1047 * robust, we'll accept hardware types of either 1 (Ethernet)
1048 * or 6 (IEEE 802.2).
1049 */
1050 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1051 r->arp_ha.sa_family != ARPHRD_ETHER &&
1052 r->arp_ha.sa_family != ARPHRD_IEEE802)
1053 return -EINVAL;
1054 break;
1055#endif
1056 default:
1057 if (r->arp_ha.sa_family != dev->type)
1058 return -EINVAL;
1059 break;
1060 }
1061
1062 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1063 err = PTR_ERR(neigh);
1064 if (!IS_ERR(neigh)) {
1065 unsigned int state = NUD_STALE;
1066 if (r->arp_flags & ATF_PERM)
1067 state = NUD_PERMANENT;
1068 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1069 r->arp_ha.sa_data : NULL, state,
1070 NEIGH_UPDATE_F_OVERRIDE |
1071 NEIGH_UPDATE_F_ADMIN, 0);
1072 neigh_release(neigh);
1073 }
1074 return err;
1075}
1076
1077static unsigned int arp_state_to_flags(struct neighbour *neigh)
1078{
1079 if (neigh->nud_state&NUD_PERMANENT)
1080 return ATF_PERM | ATF_COM;
1081 else if (neigh->nud_state&NUD_VALID)
1082 return ATF_COM;
1083 else
1084 return 0;
1085}
1086
1087/*
1088 * Get an ARP cache entry.
1089 */
1090
1091static int arp_req_get(struct arpreq *r, struct net_device *dev)
1092{
1093 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1094 struct neighbour *neigh;
1095 int err = -ENXIO;
1096
1097 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1098 if (neigh) {
1099 if (!(neigh->nud_state & NUD_NOARP)) {
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 err = 0;
1107 }
1108 neigh_release(neigh);
1109 }
1110 return err;
1111}
1112
1113static int arp_invalidate(struct net_device *dev, __be32 ip)
1114{
1115 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1116 int err = -ENXIO;
1117 struct neigh_table *tbl = &arp_tbl;
1118
1119 if (neigh) {
1120 if (neigh->nud_state & ~NUD_NOARP)
1121 err = neigh_update(neigh, NULL, NUD_FAILED,
1122 NEIGH_UPDATE_F_OVERRIDE|
1123 NEIGH_UPDATE_F_ADMIN, 0);
1124 write_lock_bh(&tbl->lock);
1125 neigh_release(neigh);
1126 neigh_remove_one(neigh, tbl);
1127 write_unlock_bh(&tbl->lock);
1128 }
1129
1130 return err;
1131}
1132
1133static int arp_req_delete_public(struct net *net, struct arpreq *r,
1134 struct net_device *dev)
1135{
1136 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1137 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1138
1139 if (mask == htonl(0xFFFFFFFF))
1140 return pneigh_delete(&arp_tbl, net, &ip, dev);
1141
1142 if (mask)
1143 return -EINVAL;
1144
1145 return arp_req_set_proxy(net, dev, 0);
1146}
1147
1148static int arp_req_delete(struct net *net, struct arpreq *r,
1149 struct net_device *dev)
1150{
1151 __be32 ip;
1152
1153 if (r->arp_flags & ATF_PUBL)
1154 return arp_req_delete_public(net, r, dev);
1155
1156 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1157 if (!dev) {
1158 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1159 if (IS_ERR(rt))
1160 return PTR_ERR(rt);
1161 dev = rt->dst.dev;
1162 ip_rt_put(rt);
1163 if (!dev)
1164 return -EINVAL;
1165 }
1166 return arp_invalidate(dev, ip);
1167}
1168
1169/*
1170 * Handle an ARP layer I/O control request.
1171 */
1172
1173int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1174{
1175 int err;
1176 struct arpreq r;
1177 struct net_device *dev = NULL;
1178
1179 switch (cmd) {
1180 case SIOCDARP:
1181 case SIOCSARP:
1182 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1183 return -EPERM;
1184 /* fall through */
1185 case SIOCGARP:
1186 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1187 if (err)
1188 return -EFAULT;
1189 break;
1190 default:
1191 return -EINVAL;
1192 }
1193
1194 if (r.arp_pa.sa_family != AF_INET)
1195 return -EPFNOSUPPORT;
1196
1197 if (!(r.arp_flags & ATF_PUBL) &&
1198 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1199 return -EINVAL;
1200 if (!(r.arp_flags & ATF_NETMASK))
1201 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1202 htonl(0xFFFFFFFFUL);
1203 rtnl_lock();
1204 if (r.arp_dev[0]) {
1205 err = -ENODEV;
1206 dev = __dev_get_by_name(net, r.arp_dev);
1207 if (!dev)
1208 goto out;
1209
1210 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1211 if (!r.arp_ha.sa_family)
1212 r.arp_ha.sa_family = dev->type;
1213 err = -EINVAL;
1214 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1215 goto out;
1216 } else if (cmd == SIOCGARP) {
1217 err = -ENODEV;
1218 goto out;
1219 }
1220
1221 switch (cmd) {
1222 case SIOCDARP:
1223 err = arp_req_delete(net, &r, dev);
1224 break;
1225 case SIOCSARP:
1226 err = arp_req_set(net, &r, dev);
1227 break;
1228 case SIOCGARP:
1229 err = arp_req_get(&r, dev);
1230 break;
1231 }
1232out:
1233 rtnl_unlock();
1234 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1235 err = -EFAULT;
1236 return err;
1237}
1238
1239static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1240 void *ptr)
1241{
1242 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1243 struct netdev_notifier_change_info *change_info;
1244
1245 switch (event) {
1246 case NETDEV_CHANGEADDR:
1247 neigh_changeaddr(&arp_tbl, dev);
1248 rt_cache_flush(dev_net(dev));
1249 break;
1250 case NETDEV_CHANGE:
1251 change_info = ptr;
1252 if (change_info->flags_changed & IFF_NOARP)
1253 neigh_changeaddr(&arp_tbl, dev);
1254 if (!netif_carrier_ok(dev))
1255 neigh_carrier_down(&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(NEIGH_ARP_TABLE, &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 void 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 buf[0] = '*';
1332 buf[1] = '\0';
1333 }
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%-17s * %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
1419/* ------------------------------------------------------------------------ */
1420
1421static int __net_init arp_net_init(struct net *net)
1422{
1423 if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops,
1424 sizeof(struct neigh_seq_state)))
1425 return -ENOMEM;
1426 return 0;
1427}
1428
1429static void __net_exit arp_net_exit(struct net *net)
1430{
1431 remove_proc_entry("arp", net->proc_net);
1432}
1433
1434static struct pernet_operations arp_net_ops = {
1435 .init = arp_net_init,
1436 .exit = arp_net_exit,
1437};
1438
1439static int __init arp_proc_init(void)
1440{
1441 return register_pernet_subsys(&arp_net_ops);
1442}
1443
1444#else /* CONFIG_PROC_FS */
1445
1446static int __init arp_proc_init(void)
1447{
1448 return 0;
1449}
1450
1451#endif /* CONFIG_PROC_FS */