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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 fallthrough;
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 */
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 .base_reachable_time = 30 * HZ,
170 .retrans_time = 1 * HZ,
171 .gc_staletime = 60 * HZ,
172 .reachable_time = 30 * HZ,
173 .delay_probe_time = 5 * HZ,
174 .queue_len_bytes = 64*1024,
175 .ucast_probes = 3,
176 .mcast_probes = 3,
177 .anycast_delay = 1 * HZ,
178 .proxy_delay = (8 * HZ) / 10,
179 .proxy_qlen = 64,
180 .locktime = 1 * HZ,
181 },
182 .gc_interval = 30 * HZ,
183 .gc_thresh1 = 128,
184 .gc_thresh2 = 512,
185 .gc_thresh3 = 1024,
186};
187EXPORT_SYMBOL(arp_tbl);
188
189int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
190{
191 switch (dev->type) {
192 case ARPHRD_ETHER:
193 case ARPHRD_FDDI:
194 case ARPHRD_IEEE802:
195 ip_eth_mc_map(addr, haddr);
196 return 0;
197 case ARPHRD_INFINIBAND:
198 ip_ib_mc_map(addr, dev->broadcast, haddr);
199 return 0;
200 case ARPHRD_IPGRE:
201 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
202 return 0;
203 default:
204 if (dir) {
205 memcpy(haddr, dev->broadcast, dev->addr_len);
206 return 0;
207 }
208 }
209 return -EINVAL;
210}
211
212
213static u32 arp_hash(const void *pkey,
214 const struct net_device *dev,
215 __u32 *hash_rnd)
216{
217 return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd);
218}
219
220static int arp_constructor(struct neighbour *neigh)
221{
222 __be32 addr = *(__be32 *)neigh->primary_key;
223 struct net_device *dev = neigh->dev;
224 struct in_device *in_dev;
225 struct neigh_parms *parms;
226
227 rcu_read_lock();
228 in_dev = __in_dev_get_rcu(dev);
229 if (in_dev == NULL) {
230 rcu_read_unlock();
231 return -EINVAL;
232 }
233
234 neigh->type = inet_addr_type(dev_net(dev), addr);
235
236 parms = in_dev->arp_parms;
237 __neigh_parms_put(neigh->parms);
238 neigh->parms = neigh_parms_clone(parms);
239 rcu_read_unlock();
240
241 if (!dev->header_ops) {
242 neigh->nud_state = NUD_NOARP;
243 neigh->ops = &arp_direct_ops;
244 neigh->output = neigh_direct_output;
245 } else {
246 /* Good devices (checked by reading texts, but only Ethernet is
247 tested)
248
249 ARPHRD_ETHER: (ethernet, apfddi)
250 ARPHRD_FDDI: (fddi)
251 ARPHRD_IEEE802: (tr)
252 ARPHRD_METRICOM: (strip)
253 ARPHRD_ARCNET:
254 etc. etc. etc.
255
256 ARPHRD_IPDDP will also work, if author repairs it.
257 I did not it, because this driver does not work even
258 in old paradigm.
259 */
260
261#if 1
262 /* So... these "amateur" devices are hopeless.
263 The only thing, that I can say now:
264 It is very sad that we need to keep ugly obsolete
265 code to make them happy.
266
267 They should be moved to more reasonable state, now
268 they use rebuild_header INSTEAD OF hard_start_xmit!!!
269 Besides that, they are sort of out of date
270 (a lot of redundant clones/copies, useless in 2.1),
271 I wonder why people believe that they work.
272 */
273 switch (dev->type) {
274 default:
275 break;
276 case ARPHRD_ROSE:
277#if IS_ENABLED(CONFIG_AX25)
278 case ARPHRD_AX25:
279#if IS_ENABLED(CONFIG_NETROM)
280 case ARPHRD_NETROM:
281#endif
282 neigh->ops = &arp_broken_ops;
283 neigh->output = neigh->ops->output;
284 return 0;
285#else
286 break;
287#endif
288 }
289#endif
290 if (neigh->type == RTN_MULTICAST) {
291 neigh->nud_state = NUD_NOARP;
292 arp_mc_map(addr, neigh->ha, dev, 1);
293 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
294 neigh->nud_state = NUD_NOARP;
295 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
296 } else if (neigh->type == RTN_BROADCAST ||
297 (dev->flags & IFF_POINTOPOINT)) {
298 neigh->nud_state = NUD_NOARP;
299 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
300 }
301
302 if (dev->header_ops->cache)
303 neigh->ops = &arp_hh_ops;
304 else
305 neigh->ops = &arp_generic_ops;
306
307 if (neigh->nud_state & NUD_VALID)
308 neigh->output = neigh->ops->connected_output;
309 else
310 neigh->output = neigh->ops->output;
311 }
312 return 0;
313}
314
315static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
316{
317 dst_link_failure(skb);
318 kfree_skb(skb);
319}
320
321static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
322{
323 __be32 saddr = 0;
324 u8 *dst_ha = NULL;
325 struct net_device *dev = neigh->dev;
326 __be32 target = *(__be32 *)neigh->primary_key;
327 int probes = atomic_read(&neigh->probes);
328 struct in_device *in_dev;
329
330 rcu_read_lock();
331 in_dev = __in_dev_get_rcu(dev);
332 if (!in_dev) {
333 rcu_read_unlock();
334 return;
335 }
336 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
337 default:
338 case 0: /* By default announce any local IP */
339 if (skb && inet_addr_type(dev_net(dev),
340 ip_hdr(skb)->saddr) == RTN_LOCAL)
341 saddr = ip_hdr(skb)->saddr;
342 break;
343 case 1: /* Restrict announcements of saddr in same subnet */
344 if (!skb)
345 break;
346 saddr = ip_hdr(skb)->saddr;
347 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) {
348 /* saddr should be known to target */
349 if (inet_addr_onlink(in_dev, target, saddr))
350 break;
351 }
352 saddr = 0;
353 break;
354 case 2: /* Avoid secondary IPs, get a primary/preferred one */
355 break;
356 }
357 rcu_read_unlock();
358
359 if (!saddr)
360 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
361
362 probes -= neigh->parms->ucast_probes;
363 if (probes < 0) {
364 if (!(neigh->nud_state & NUD_VALID))
365 pr_debug("trying to ucast probe in NUD_INVALID\n");
366 dst_ha = neigh->ha;
367 read_lock_bh(&neigh->lock);
368 } else {
369 probes -= neigh->parms->app_probes;
370 if (probes < 0) {
371#ifdef CONFIG_ARPD
372 neigh_app_ns(neigh);
373#endif
374 return;
375 }
376 }
377
378 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
379 dst_ha, dev->dev_addr, NULL);
380 if (dst_ha)
381 read_unlock_bh(&neigh->lock);
382}
383
384static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
385{
386 int scope;
387
388 switch (IN_DEV_ARP_IGNORE(in_dev)) {
389 case 0: /* Reply, the tip is already validated */
390 return 0;
391 case 1: /* Reply only if tip is configured on the incoming interface */
392 sip = 0;
393 scope = RT_SCOPE_HOST;
394 break;
395 case 2: /*
396 * Reply only if tip is configured on the incoming interface
397 * and is in same subnet as sip
398 */
399 scope = RT_SCOPE_HOST;
400 break;
401 case 3: /* Do not reply for scope host addresses */
402 sip = 0;
403 scope = RT_SCOPE_LINK;
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(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 = skb_rtable(skb)->rt_gateway;
479
480 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr,
481 paddr, dev))
482 return 0;
483
484 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
485
486 if (n) {
487 n->used = jiffies;
488 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) {
489 neigh_ha_snapshot(haddr, n, dev);
490 neigh_release(n);
491 return 0;
492 }
493 neigh_release(n);
494 } else
495 kfree_skb(skb);
496 return 1;
497}
498EXPORT_SYMBOL(arp_find);
499
500/* END OF OBSOLETE FUNCTIONS */
501
502/*
503 * Check if we can use proxy ARP for this path
504 */
505static inline int arp_fwd_proxy(struct in_device *in_dev,
506 struct net_device *dev, struct rtable *rt)
507{
508 struct in_device *out_dev;
509 int imi, omi = -1;
510
511 if (rt->dst.dev == dev)
512 return 0;
513
514 if (!IN_DEV_PROXY_ARP(in_dev))
515 return 0;
516 imi = IN_DEV_MEDIUM_ID(in_dev);
517 if (imi == 0)
518 return 1;
519 if (imi == -1)
520 return 0;
521
522 /* place to check for proxy_arp for routes */
523
524 out_dev = __in_dev_get_rcu(rt->dst.dev);
525 if (out_dev)
526 omi = IN_DEV_MEDIUM_ID(out_dev);
527
528 return omi != imi && omi != -1;
529}
530
531/*
532 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
533 *
534 * RFC3069 supports proxy arp replies back to the same interface. This
535 * is done to support (ethernet) switch features, like RFC 3069, where
536 * the individual ports are not allowed to communicate with each
537 * other, BUT they are allowed to talk to the upstream router. As
538 * described in RFC 3069, it is possible to allow these hosts to
539 * communicate through the upstream router, by proxy_arp'ing.
540 *
541 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
542 *
543 * This technology is known by different names:
544 * In RFC 3069 it is called VLAN Aggregation.
545 * Cisco and Allied Telesyn call it Private VLAN.
546 * Hewlett-Packard call it Source-Port filtering or port-isolation.
547 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
548 *
549 */
550static inline int arp_fwd_pvlan(struct in_device *in_dev,
551 struct net_device *dev, struct rtable *rt,
552 __be32 sip, __be32 tip)
553{
554 /* Private VLAN is only concerned about the same ethernet segment */
555 if (rt->dst.dev != dev)
556 return 0;
557
558 /* Don't reply on self probes (often done by windowz boxes)*/
559 if (sip == tip)
560 return 0;
561
562 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
563 return 1;
564 else
565 return 0;
566}
567
568/*
569 * Interface to link layer: send routine and receive handler.
570 */
571
572/*
573 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
574 * message.
575 */
576struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
577 struct net_device *dev, __be32 src_ip,
578 const unsigned char *dest_hw,
579 const unsigned char *src_hw,
580 const unsigned char *target_hw)
581{
582 struct sk_buff *skb;
583 struct arphdr *arp;
584 unsigned char *arp_ptr;
585 int hlen = LL_RESERVED_SPACE(dev);
586 int tlen = dev->needed_tailroom;
587
588 /*
589 * Allocate a buffer
590 */
591
592 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
593 if (skb == NULL)
594 return NULL;
595
596 skb_reserve(skb, hlen);
597 skb_reset_network_header(skb);
598 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
599 skb->dev = dev;
600 skb->protocol = htons(ETH_P_ARP);
601 if (src_hw == NULL)
602 src_hw = dev->dev_addr;
603 if (dest_hw == NULL)
604 dest_hw = dev->broadcast;
605
606 /*
607 * Fill the device header for the ARP frame
608 */
609 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
610 goto out;
611
612 /*
613 * Fill out the arp protocol part.
614 *
615 * The arp hardware type should match the device type, except for FDDI,
616 * which (according to RFC 1390) should always equal 1 (Ethernet).
617 */
618 /*
619 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
620 * DIX code for the protocol. Make these device structure fields.
621 */
622 switch (dev->type) {
623 default:
624 arp->ar_hrd = htons(dev->type);
625 arp->ar_pro = htons(ETH_P_IP);
626 break;
627
628#if IS_ENABLED(CONFIG_AX25)
629 case ARPHRD_AX25:
630 arp->ar_hrd = htons(ARPHRD_AX25);
631 arp->ar_pro = htons(AX25_P_IP);
632 break;
633
634#if IS_ENABLED(CONFIG_NETROM)
635 case ARPHRD_NETROM:
636 arp->ar_hrd = htons(ARPHRD_NETROM);
637 arp->ar_pro = htons(AX25_P_IP);
638 break;
639#endif
640#endif
641
642#if IS_ENABLED(CONFIG_FDDI)
643 case ARPHRD_FDDI:
644 arp->ar_hrd = htons(ARPHRD_ETHER);
645 arp->ar_pro = htons(ETH_P_IP);
646 break;
647#endif
648 }
649
650 arp->ar_hln = dev->addr_len;
651 arp->ar_pln = 4;
652 arp->ar_op = htons(type);
653
654 arp_ptr = (unsigned char *)(arp + 1);
655
656 memcpy(arp_ptr, src_hw, dev->addr_len);
657 arp_ptr += dev->addr_len;
658 memcpy(arp_ptr, &src_ip, 4);
659 arp_ptr += 4;
660 if (target_hw != NULL)
661 memcpy(arp_ptr, target_hw, dev->addr_len);
662 else
663 memset(arp_ptr, 0, dev->addr_len);
664 arp_ptr += dev->addr_len;
665 memcpy(arp_ptr, &dest_ip, 4);
666
667 return skb;
668
669out:
670 kfree_skb(skb);
671 return NULL;
672}
673EXPORT_SYMBOL(arp_create);
674
675/*
676 * Send an arp packet.
677 */
678void arp_xmit(struct sk_buff *skb)
679{
680 /* Send it off, maybe filter it using firewalling first. */
681 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
682}
683EXPORT_SYMBOL(arp_xmit);
684
685/*
686 * Create and send an arp packet.
687 */
688void arp_send(int type, int ptype, __be32 dest_ip,
689 struct net_device *dev, __be32 src_ip,
690 const unsigned char *dest_hw, const unsigned char *src_hw,
691 const unsigned char *target_hw)
692{
693 struct sk_buff *skb;
694
695 /*
696 * No arp on this interface.
697 */
698
699 if (dev->flags&IFF_NOARP)
700 return;
701
702 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
703 dest_hw, src_hw, target_hw);
704 if (skb == NULL)
705 return;
706
707 arp_xmit(skb);
708}
709EXPORT_SYMBOL(arp_send);
710
711/*
712 * Process an arp request.
713 */
714
715static int arp_process(struct sk_buff *skb)
716{
717 struct net_device *dev = skb->dev;
718 struct in_device *in_dev = __in_dev_get_rcu(dev);
719 struct arphdr *arp;
720 unsigned char *arp_ptr;
721 struct rtable *rt;
722 unsigned char *sha;
723 __be32 sip, tip;
724 u16 dev_type = dev->type;
725 int addr_type;
726 struct neighbour *n;
727 struct net *net = dev_net(dev);
728
729 /* arp_rcv below verifies the ARP header and verifies the device
730 * is ARP'able.
731 */
732
733 if (in_dev == NULL)
734 goto out;
735
736 arp = arp_hdr(skb);
737
738 switch (dev_type) {
739 default:
740 if (arp->ar_pro != htons(ETH_P_IP) ||
741 htons(dev_type) != arp->ar_hrd)
742 goto out;
743 break;
744 case ARPHRD_ETHER:
745 case ARPHRD_FDDI:
746 case ARPHRD_IEEE802:
747 /*
748 * ETHERNET, and Fibre Channel (which are IEEE 802
749 * devices, according to RFC 2625) devices will accept ARP
750 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
751 * This is the case also of FDDI, where the RFC 1390 says that
752 * FDDI devices should accept ARP hardware of (1) Ethernet,
753 * however, to be more robust, we'll accept both 1 (Ethernet)
754 * or 6 (IEEE 802.2)
755 */
756 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
757 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
758 arp->ar_pro != htons(ETH_P_IP))
759 goto out;
760 break;
761 case ARPHRD_AX25:
762 if (arp->ar_pro != htons(AX25_P_IP) ||
763 arp->ar_hrd != htons(ARPHRD_AX25))
764 goto out;
765 break;
766 case ARPHRD_NETROM:
767 if (arp->ar_pro != htons(AX25_P_IP) ||
768 arp->ar_hrd != htons(ARPHRD_NETROM))
769 goto out;
770 break;
771 }
772
773 /* Understand only these message types */
774
775 if (arp->ar_op != htons(ARPOP_REPLY) &&
776 arp->ar_op != htons(ARPOP_REQUEST))
777 goto out;
778
779/*
780 * Extract fields
781 */
782 arp_ptr = (unsigned char *)(arp + 1);
783 sha = arp_ptr;
784 arp_ptr += dev->addr_len;
785 memcpy(&sip, arp_ptr, 4);
786 arp_ptr += 4;
787 arp_ptr += dev->addr_len;
788 memcpy(&tip, arp_ptr, 4);
789/*
790 * Check for bad requests for 127.x.x.x and requests for multicast
791 * addresses. If this is one such, delete it.
792 */
793 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
794 goto out;
795
796/*
797 * Special case: We must set Frame Relay source Q.922 address
798 */
799 if (dev_type == ARPHRD_DLCI)
800 sha = dev->broadcast;
801
802/*
803 * Process entry. The idea here is we want to send a reply if it is a
804 * request for us or if it is a request for someone else that we hold
805 * a proxy for. We want to add an entry to our cache if it is a reply
806 * to us or if it is a request for our address.
807 * (The assumption for this last is that if someone is requesting our
808 * address, they are probably intending to talk to us, so it saves time
809 * if we cache their address. Their address is also probably not in
810 * our cache, since ours is not in their cache.)
811 *
812 * Putting this another way, we only care about replies if they are to
813 * us, in which case we add them to the cache. For requests, we care
814 * about those for us and those for our proxies. We reply to both,
815 * and in the case of requests for us we add the requester to the arp
816 * cache.
817 */
818
819 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
820 if (sip == 0) {
821 if (arp->ar_op == htons(ARPOP_REQUEST) &&
822 inet_addr_type(net, tip) == RTN_LOCAL &&
823 !arp_ignore(in_dev, sip, tip))
824 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
825 dev->dev_addr, sha);
826 goto out;
827 }
828
829 if (arp->ar_op == htons(ARPOP_REQUEST) &&
830 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
831
832 rt = skb_rtable(skb);
833 addr_type = rt->rt_type;
834
835 if (addr_type == RTN_LOCAL) {
836 int dont_send;
837
838 dont_send = arp_ignore(in_dev, sip, tip);
839 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
840 dont_send = arp_filter(sip, tip, dev);
841 if (!dont_send) {
842 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
843 if (n) {
844 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
845 dev, tip, sha, dev->dev_addr,
846 sha);
847 neigh_release(n);
848 }
849 }
850 goto out;
851 } else if (IN_DEV_FORWARD(in_dev)) {
852 if (addr_type == RTN_UNICAST &&
853 (arp_fwd_proxy(in_dev, dev, rt) ||
854 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
855 (rt->dst.dev != dev &&
856 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
857 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
858 if (n)
859 neigh_release(n);
860
861 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
862 skb->pkt_type == PACKET_HOST ||
863 in_dev->arp_parms->proxy_delay == 0) {
864 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
865 dev, tip, sha, dev->dev_addr,
866 sha);
867 } else {
868 pneigh_enqueue(&arp_tbl,
869 in_dev->arp_parms, skb);
870 return 0;
871 }
872 goto out;
873 }
874 }
875 }
876
877 /* Update our ARP tables */
878
879 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
880
881 if (IN_DEV_ARP_ACCEPT(in_dev)) {
882 /* Unsolicited ARP is not accepted by default.
883 It is possible, that this option should be enabled for some
884 devices (strip is candidate)
885 */
886 if (n == NULL &&
887 (arp->ar_op == htons(ARPOP_REPLY) ||
888 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) &&
889 inet_addr_type(net, sip) == RTN_UNICAST)
890 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
891 }
892
893 if (n) {
894 int state = NUD_REACHABLE;
895 int override;
896
897 /* If several different ARP replies follows back-to-back,
898 use the FIRST one. It is possible, if several proxy
899 agents are active. Taking the first reply prevents
900 arp trashing and chooses the fastest router.
901 */
902 override = time_after(jiffies, n->updated + n->parms->locktime);
903
904 /* Broadcast replies and request packets
905 do not assert neighbour reachability.
906 */
907 if (arp->ar_op != htons(ARPOP_REPLY) ||
908 skb->pkt_type != PACKET_HOST)
909 state = NUD_STALE;
910 neigh_update(n, sha, state,
911 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
912 neigh_release(n);
913 }
914
915out:
916 consume_skb(skb);
917 return 0;
918}
919
920static void parp_redo(struct sk_buff *skb)
921{
922 arp_process(skb);
923}
924
925
926/*
927 * Receive an arp request from the device layer.
928 */
929
930static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
931 struct packet_type *pt, struct net_device *orig_dev)
932{
933 struct arphdr *arp;
934
935 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
936 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
937 goto freeskb;
938
939 arp = arp_hdr(skb);
940 if (arp->ar_hln != dev->addr_len ||
941 dev->flags & IFF_NOARP ||
942 skb->pkt_type == PACKET_OTHERHOST ||
943 skb->pkt_type == PACKET_LOOPBACK ||
944 arp->ar_pln != 4)
945 goto freeskb;
946
947 skb = skb_share_check(skb, GFP_ATOMIC);
948 if (skb == NULL)
949 goto out_of_mem;
950
951 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
952
953 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
954
955freeskb:
956 kfree_skb(skb);
957out_of_mem:
958 return 0;
959}
960
961/*
962 * User level interface (ioctl)
963 */
964
965/*
966 * Set (create) an ARP cache entry.
967 */
968
969static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
970{
971 if (dev == NULL) {
972 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
973 return 0;
974 }
975 if (__in_dev_get_rtnl(dev)) {
976 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
977 return 0;
978 }
979 return -ENXIO;
980}
981
982static int arp_req_set_public(struct net *net, struct arpreq *r,
983 struct net_device *dev)
984{
985 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
986 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
987
988 if (mask && mask != htonl(0xFFFFFFFF))
989 return -EINVAL;
990 if (!dev && (r->arp_flags & ATF_COM)) {
991 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
992 r->arp_ha.sa_data);
993 if (!dev)
994 return -ENODEV;
995 }
996 if (mask) {
997 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL)
998 return -ENOBUFS;
999 return 0;
1000 }
1001
1002 return arp_req_set_proxy(net, dev, 1);
1003}
1004
1005static int arp_req_set(struct net *net, struct arpreq *r,
1006 struct net_device *dev)
1007{
1008 __be32 ip;
1009 struct neighbour *neigh;
1010 int err;
1011
1012 if (r->arp_flags & ATF_PUBL)
1013 return arp_req_set_public(net, r, dev);
1014
1015 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1016 if (r->arp_flags & ATF_PERM)
1017 r->arp_flags |= ATF_COM;
1018 if (dev == NULL) {
1019 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1020
1021 if (IS_ERR(rt))
1022 return PTR_ERR(rt);
1023 dev = rt->dst.dev;
1024 ip_rt_put(rt);
1025 if (!dev)
1026 return -EINVAL;
1027 }
1028 switch (dev->type) {
1029#if IS_ENABLED(CONFIG_FDDI)
1030 case ARPHRD_FDDI:
1031 /*
1032 * According to RFC 1390, FDDI devices should accept ARP
1033 * hardware types of 1 (Ethernet). However, to be more
1034 * robust, we'll accept hardware types of either 1 (Ethernet)
1035 * or 6 (IEEE 802.2).
1036 */
1037 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1038 r->arp_ha.sa_family != ARPHRD_ETHER &&
1039 r->arp_ha.sa_family != ARPHRD_IEEE802)
1040 return -EINVAL;
1041 break;
1042#endif
1043 default:
1044 if (r->arp_ha.sa_family != dev->type)
1045 return -EINVAL;
1046 break;
1047 }
1048
1049 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1050 err = PTR_ERR(neigh);
1051 if (!IS_ERR(neigh)) {
1052 unsigned int state = NUD_STALE;
1053 if (r->arp_flags & ATF_PERM)
1054 state = NUD_PERMANENT;
1055 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1056 r->arp_ha.sa_data : NULL, state,
1057 NEIGH_UPDATE_F_OVERRIDE |
1058 NEIGH_UPDATE_F_ADMIN);
1059 neigh_release(neigh);
1060 }
1061 return err;
1062}
1063
1064static unsigned int arp_state_to_flags(struct neighbour *neigh)
1065{
1066 if (neigh->nud_state&NUD_PERMANENT)
1067 return ATF_PERM | ATF_COM;
1068 else if (neigh->nud_state&NUD_VALID)
1069 return ATF_COM;
1070 else
1071 return 0;
1072}
1073
1074/*
1075 * Get an ARP cache entry.
1076 */
1077
1078static int arp_req_get(struct arpreq *r, struct net_device *dev)
1079{
1080 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1081 struct neighbour *neigh;
1082 int err = -ENXIO;
1083
1084 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1085 if (neigh) {
1086 read_lock_bh(&neigh->lock);
1087 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1088 r->arp_flags = arp_state_to_flags(neigh);
1089 read_unlock_bh(&neigh->lock);
1090 r->arp_ha.sa_family = dev->type;
1091 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1092 neigh_release(neigh);
1093 err = 0;
1094 }
1095 return err;
1096}
1097
1098int arp_invalidate(struct net_device *dev, __be32 ip)
1099{
1100 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1101 int err = -ENXIO;
1102
1103 if (neigh) {
1104 if (neigh->nud_state & ~NUD_NOARP)
1105 err = neigh_update(neigh, NULL, NUD_FAILED,
1106 NEIGH_UPDATE_F_OVERRIDE|
1107 NEIGH_UPDATE_F_ADMIN);
1108 neigh_release(neigh);
1109 }
1110
1111 return err;
1112}
1113EXPORT_SYMBOL(arp_invalidate);
1114
1115static int arp_req_delete_public(struct net *net, struct arpreq *r,
1116 struct net_device *dev)
1117{
1118 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1119 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1120
1121 if (mask == htonl(0xFFFFFFFF))
1122 return pneigh_delete(&arp_tbl, net, &ip, dev);
1123
1124 if (mask)
1125 return -EINVAL;
1126
1127 return arp_req_set_proxy(net, dev, 0);
1128}
1129
1130static int arp_req_delete(struct net *net, struct arpreq *r,
1131 struct net_device *dev)
1132{
1133 __be32 ip;
1134
1135 if (r->arp_flags & ATF_PUBL)
1136 return arp_req_delete_public(net, r, dev);
1137
1138 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1139 if (dev == NULL) {
1140 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1141 if (IS_ERR(rt))
1142 return PTR_ERR(rt);
1143 dev = rt->dst.dev;
1144 ip_rt_put(rt);
1145 if (!dev)
1146 return -EINVAL;
1147 }
1148 return arp_invalidate(dev, ip);
1149}
1150
1151/*
1152 * Handle an ARP layer I/O control request.
1153 */
1154
1155int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1156{
1157 int err;
1158 struct arpreq r;
1159 struct net_device *dev = NULL;
1160
1161 switch (cmd) {
1162 case SIOCDARP:
1163 case SIOCSARP:
1164 if (!capable(CAP_NET_ADMIN))
1165 return -EPERM;
1166 case SIOCGARP:
1167 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1168 if (err)
1169 return -EFAULT;
1170 break;
1171 default:
1172 return -EINVAL;
1173 }
1174
1175 if (r.arp_pa.sa_family != AF_INET)
1176 return -EPFNOSUPPORT;
1177
1178 if (!(r.arp_flags & ATF_PUBL) &&
1179 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1180 return -EINVAL;
1181 if (!(r.arp_flags & ATF_NETMASK))
1182 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1183 htonl(0xFFFFFFFFUL);
1184 rtnl_lock();
1185 if (r.arp_dev[0]) {
1186 err = -ENODEV;
1187 dev = __dev_get_by_name(net, r.arp_dev);
1188 if (dev == NULL)
1189 goto out;
1190
1191 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1192 if (!r.arp_ha.sa_family)
1193 r.arp_ha.sa_family = dev->type;
1194 err = -EINVAL;
1195 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1196 goto out;
1197 } else if (cmd == SIOCGARP) {
1198 err = -ENODEV;
1199 goto out;
1200 }
1201
1202 switch (cmd) {
1203 case SIOCDARP:
1204 err = arp_req_delete(net, &r, dev);
1205 break;
1206 case SIOCSARP:
1207 err = arp_req_set(net, &r, dev);
1208 break;
1209 case SIOCGARP:
1210 err = arp_req_get(&r, dev);
1211 break;
1212 }
1213out:
1214 rtnl_unlock();
1215 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1216 err = -EFAULT;
1217 return err;
1218}
1219
1220static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1221 void *ptr)
1222{
1223 struct net_device *dev = ptr;
1224
1225 switch (event) {
1226 case NETDEV_CHANGEADDR:
1227 neigh_changeaddr(&arp_tbl, dev);
1228 rt_cache_flush(dev_net(dev), 0);
1229 break;
1230 default:
1231 break;
1232 }
1233
1234 return NOTIFY_DONE;
1235}
1236
1237static struct notifier_block arp_netdev_notifier = {
1238 .notifier_call = arp_netdev_event,
1239};
1240
1241/* Note, that it is not on notifier chain.
1242 It is necessary, that this routine was called after route cache will be
1243 flushed.
1244 */
1245void arp_ifdown(struct net_device *dev)
1246{
1247 neigh_ifdown(&arp_tbl, dev);
1248}
1249
1250
1251/*
1252 * Called once on startup.
1253 */
1254
1255static struct packet_type arp_packet_type __read_mostly = {
1256 .type = cpu_to_be16(ETH_P_ARP),
1257 .func = arp_rcv,
1258};
1259
1260static int arp_proc_init(void);
1261
1262void __init arp_init(void)
1263{
1264 neigh_table_init(&arp_tbl);
1265
1266 dev_add_pack(&arp_packet_type);
1267 arp_proc_init();
1268#ifdef CONFIG_SYSCTL
1269 neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL);
1270#endif
1271 register_netdevice_notifier(&arp_netdev_notifier);
1272}
1273
1274#ifdef CONFIG_PROC_FS
1275#if IS_ENABLED(CONFIG_AX25)
1276
1277/* ------------------------------------------------------------------------ */
1278/*
1279 * ax25 -> ASCII conversion
1280 */
1281static char *ax2asc2(ax25_address *a, char *buf)
1282{
1283 char c, *s;
1284 int n;
1285
1286 for (n = 0, s = buf; n < 6; n++) {
1287 c = (a->ax25_call[n] >> 1) & 0x7F;
1288
1289 if (c != ' ')
1290 *s++ = c;
1291 }
1292
1293 *s++ = '-';
1294 n = (a->ax25_call[6] >> 1) & 0x0F;
1295 if (n > 9) {
1296 *s++ = '1';
1297 n -= 10;
1298 }
1299
1300 *s++ = n + '0';
1301 *s++ = '\0';
1302
1303 if (*buf == '\0' || *buf == '-')
1304 return "*";
1305
1306 return buf;
1307}
1308#endif /* CONFIG_AX25 */
1309
1310#define HBUFFERLEN 30
1311
1312static void arp_format_neigh_entry(struct seq_file *seq,
1313 struct neighbour *n)
1314{
1315 char hbuffer[HBUFFERLEN];
1316 int k, j;
1317 char tbuf[16];
1318 struct net_device *dev = n->dev;
1319 int hatype = dev->type;
1320
1321 read_lock(&n->lock);
1322 /* Convert hardware address to XX:XX:XX:XX ... form. */
1323#if IS_ENABLED(CONFIG_AX25)
1324 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1325 ax2asc2((ax25_address *)n->ha, hbuffer);
1326 else {
1327#endif
1328 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1329 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1330 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1331 hbuffer[k++] = ':';
1332 }
1333 if (k != 0)
1334 --k;
1335 hbuffer[k] = 0;
1336#if IS_ENABLED(CONFIG_AX25)
1337 }
1338#endif
1339 sprintf(tbuf, "%pI4", n->primary_key);
1340 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1341 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1342 read_unlock(&n->lock);
1343}
1344
1345static void arp_format_pneigh_entry(struct seq_file *seq,
1346 struct pneigh_entry *n)
1347{
1348 struct net_device *dev = n->dev;
1349 int hatype = dev ? dev->type : 0;
1350 char tbuf[16];
1351
1352 sprintf(tbuf, "%pI4", n->key);
1353 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1354 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1355 dev ? dev->name : "*");
1356}
1357
1358static int arp_seq_show(struct seq_file *seq, void *v)
1359{
1360 if (v == SEQ_START_TOKEN) {
1361 seq_puts(seq, "IP address HW type Flags "
1362 "HW address Mask Device\n");
1363 } else {
1364 struct neigh_seq_state *state = seq->private;
1365
1366 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1367 arp_format_pneigh_entry(seq, v);
1368 else
1369 arp_format_neigh_entry(seq, v);
1370 }
1371
1372 return 0;
1373}
1374
1375static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1376{
1377 /* Don't want to confuse "arp -a" w/ magic entries,
1378 * so we tell the generic iterator to skip NUD_NOARP.
1379 */
1380 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1381}
1382
1383/* ------------------------------------------------------------------------ */
1384
1385static const struct seq_operations arp_seq_ops = {
1386 .start = arp_seq_start,
1387 .next = neigh_seq_next,
1388 .stop = neigh_seq_stop,
1389 .show = arp_seq_show,
1390};
1391
1392static int arp_seq_open(struct inode *inode, struct file *file)
1393{
1394 return seq_open_net(inode, file, &arp_seq_ops,
1395 sizeof(struct neigh_seq_state));
1396}
1397
1398static const struct file_operations arp_seq_fops = {
1399 .owner = THIS_MODULE,
1400 .open = arp_seq_open,
1401 .read = seq_read,
1402 .llseek = seq_lseek,
1403 .release = seq_release_net,
1404};
1405
1406
1407static int __net_init arp_net_init(struct net *net)
1408{
1409 if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops))
1410 return -ENOMEM;
1411 return 0;
1412}
1413
1414static void __net_exit arp_net_exit(struct net *net)
1415{
1416 proc_net_remove(net, "arp");
1417}
1418
1419static struct pernet_operations arp_net_ops = {
1420 .init = arp_net_init,
1421 .exit = arp_net_exit,
1422};
1423
1424static int __init arp_proc_init(void)
1425{
1426 return register_pernet_subsys(&arp_net_ops);
1427}
1428
1429#else /* CONFIG_PROC_FS */
1430
1431static int __init arp_proc_init(void)
1432{
1433 return 0;
1434}
1435
1436#endif /* CONFIG_PROC_FS */