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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/hex.h>
83#include <linux/in.h>
84#include <linux/mm.h>
85#include <linux/inet.h>
86#include <linux/inetdevice.h>
87#include <linux/netdevice.h>
88#include <linux/etherdevice.h>
89#include <linux/fddidevice.h>
90#include <linux/if_arp.h>
91#include <linux/skbuff.h>
92#include <linux/proc_fs.h>
93#include <linux/seq_file.h>
94#include <linux/stat.h>
95#include <linux/init.h>
96#include <linux/net.h>
97#include <linux/rcupdate.h>
98#include <linux/slab.h>
99#ifdef CONFIG_SYSCTL
100#include <linux/sysctl.h>
101#endif
102
103#include <net/net_namespace.h>
104#include <net/ip.h>
105#include <net/icmp.h>
106#include <net/route.h>
107#include <net/protocol.h>
108#include <net/tcp.h>
109#include <net/sock.h>
110#include <net/arp.h>
111#include <net/ax25.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);
128static int arp_is_multicast(const void *pkey);
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
152struct neigh_table arp_tbl = {
153 .family = AF_INET,
154 .key_len = 4,
155 .protocol = cpu_to_be16(ETH_P_IP),
156 .hash = arp_hash,
157 .key_eq = arp_key_eq,
158 .constructor = arp_constructor,
159 .proxy_redo = parp_redo,
160 .is_multicast = arp_is_multicast,
161 .id = "arp_cache",
162 .parms = {
163 .tbl = &arp_tbl,
164 .reachable_time = 30 * HZ,
165 .data = {
166 [NEIGH_VAR_MCAST_PROBES] = 3,
167 [NEIGH_VAR_UCAST_PROBES] = 3,
168 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
169 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
170 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
171 [NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
172 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
173 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_DEFAULT,
174 [NEIGH_VAR_PROXY_QLEN] = 64,
175 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
176 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
177 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
178 },
179 },
180 .gc_interval = 30 * HZ,
181 .gc_thresh1 = 128,
182 .gc_thresh2 = 512,
183 .gc_thresh3 = 1024,
184};
185EXPORT_SYMBOL(arp_tbl);
186
187int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
188{
189 switch (dev->type) {
190 case ARPHRD_ETHER:
191 case ARPHRD_FDDI:
192 case ARPHRD_IEEE802:
193 ip_eth_mc_map(addr, haddr);
194 return 0;
195 case ARPHRD_INFINIBAND:
196 ip_ib_mc_map(addr, dev->broadcast, haddr);
197 return 0;
198 case ARPHRD_IPGRE:
199 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
200 return 0;
201 default:
202 if (dir) {
203 memcpy(haddr, dev->broadcast, dev->addr_len);
204 return 0;
205 }
206 }
207 return -EINVAL;
208}
209
210
211static u32 arp_hash(const void *pkey,
212 const struct net_device *dev,
213 __u32 *hash_rnd)
214{
215 return arp_hashfn(pkey, dev, hash_rnd);
216}
217
218static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
219{
220 return neigh_key_eq32(neigh, pkey);
221}
222
223static int arp_constructor(struct neighbour *neigh)
224{
225 __be32 addr;
226 struct net_device *dev = neigh->dev;
227 struct in_device *in_dev;
228 struct neigh_parms *parms;
229 u32 inaddr_any = INADDR_ANY;
230
231 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
232 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len);
233
234 addr = *(__be32 *)neigh->primary_key;
235 rcu_read_lock();
236 in_dev = __in_dev_get_rcu(dev);
237 if (!in_dev) {
238 rcu_read_unlock();
239 return -EINVAL;
240 }
241
242 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
243
244 parms = in_dev->arp_parms;
245 __neigh_parms_put(neigh->parms);
246 neigh->parms = neigh_parms_clone(parms);
247 rcu_read_unlock();
248
249 if (!dev->header_ops) {
250 neigh->nud_state = NUD_NOARP;
251 neigh->ops = &arp_direct_ops;
252 neigh->output = neigh_direct_output;
253 } else {
254 /* Good devices (checked by reading texts, but only Ethernet is
255 tested)
256
257 ARPHRD_ETHER: (ethernet, apfddi)
258 ARPHRD_FDDI: (fddi)
259 ARPHRD_IEEE802: (tr)
260 ARPHRD_METRICOM: (strip)
261 ARPHRD_ARCNET:
262 etc. etc. etc.
263
264 ARPHRD_IPDDP will also work, if author repairs it.
265 I did not it, because this driver does not work even
266 in old paradigm.
267 */
268
269 if (neigh->type == RTN_MULTICAST) {
270 neigh->nud_state = NUD_NOARP;
271 arp_mc_map(addr, neigh->ha, dev, 1);
272 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
273 neigh->nud_state = NUD_NOARP;
274 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
275 } else if (neigh->type == RTN_BROADCAST ||
276 (dev->flags & IFF_POINTOPOINT)) {
277 neigh->nud_state = NUD_NOARP;
278 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
279 }
280
281 if (dev->header_ops->cache)
282 neigh->ops = &arp_hh_ops;
283 else
284 neigh->ops = &arp_generic_ops;
285
286 if (neigh->nud_state & NUD_VALID)
287 neigh->output = neigh->ops->connected_output;
288 else
289 neigh->output = neigh->ops->output;
290 }
291 return 0;
292}
293
294static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
295{
296 dst_link_failure(skb);
297 kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_FAILED);
298}
299
300/* Create and send an arp packet. */
301static void arp_send_dst(int type, int ptype, __be32 dest_ip,
302 struct net_device *dev, __be32 src_ip,
303 const unsigned char *dest_hw,
304 const unsigned char *src_hw,
305 const unsigned char *target_hw,
306 struct dst_entry *dst)
307{
308 struct sk_buff *skb;
309
310 /* arp on this interface. */
311 if (dev->flags & IFF_NOARP)
312 return;
313
314 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
315 dest_hw, src_hw, target_hw);
316 if (!skb)
317 return;
318
319 skb_dst_set(skb, dst_clone(dst));
320 arp_xmit(skb);
321}
322
323void arp_send(int type, int ptype, __be32 dest_ip,
324 struct net_device *dev, __be32 src_ip,
325 const unsigned char *dest_hw, const unsigned char *src_hw,
326 const unsigned char *target_hw)
327{
328 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
329 target_hw, NULL);
330}
331EXPORT_SYMBOL(arp_send);
332
333static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
334{
335 __be32 saddr = 0;
336 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
337 struct net_device *dev = neigh->dev;
338 __be32 target = *(__be32 *)neigh->primary_key;
339 int probes = atomic_read(&neigh->probes);
340 struct in_device *in_dev;
341 struct dst_entry *dst = NULL;
342
343 rcu_read_lock();
344 in_dev = __in_dev_get_rcu(dev);
345 if (!in_dev) {
346 rcu_read_unlock();
347 return;
348 }
349 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
350 default:
351 case 0: /* By default announce any local IP */
352 if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
353 ip_hdr(skb)->saddr) == RTN_LOCAL)
354 saddr = ip_hdr(skb)->saddr;
355 break;
356 case 1: /* Restrict announcements of saddr in same subnet */
357 if (!skb)
358 break;
359 saddr = ip_hdr(skb)->saddr;
360 if (inet_addr_type_dev_table(dev_net(dev), dev,
361 saddr) == RTN_LOCAL) {
362 /* saddr should be known to target */
363 if (inet_addr_onlink(in_dev, target, saddr))
364 break;
365 }
366 saddr = 0;
367 break;
368 case 2: /* Avoid secondary IPs, get a primary/preferred one */
369 break;
370 }
371 rcu_read_unlock();
372
373 if (!saddr)
374 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
375
376 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
377 if (probes < 0) {
378 if (!(READ_ONCE(neigh->nud_state) & NUD_VALID))
379 pr_debug("trying to ucast probe in NUD_INVALID\n");
380 neigh_ha_snapshot(dst_ha, neigh, dev);
381 dst_hw = dst_ha;
382 } else {
383 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
384 if (probes < 0) {
385 neigh_app_ns(neigh);
386 return;
387 }
388 }
389
390 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
391 dst = skb_dst(skb);
392 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
393 dst_hw, dev->dev_addr, NULL, dst);
394}
395
396static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
397{
398 struct net *net = dev_net(in_dev->dev);
399 int scope;
400
401 switch (IN_DEV_ARP_IGNORE(in_dev)) {
402 case 0: /* Reply, the tip is already validated */
403 return 0;
404 case 1: /* Reply only if tip is configured on the incoming interface */
405 sip = 0;
406 scope = RT_SCOPE_HOST;
407 break;
408 case 2: /*
409 * Reply only if tip is configured on the incoming interface
410 * and is in same subnet as sip
411 */
412 scope = RT_SCOPE_HOST;
413 break;
414 case 3: /* Do not reply for scope host addresses */
415 sip = 0;
416 scope = RT_SCOPE_LINK;
417 in_dev = NULL;
418 break;
419 case 4: /* Reserved */
420 case 5:
421 case 6:
422 case 7:
423 return 0;
424 case 8: /* Do not reply */
425 return 1;
426 default:
427 return 0;
428 }
429 return !inet_confirm_addr(net, in_dev, sip, tip, scope);
430}
431
432static int arp_accept(struct in_device *in_dev, __be32 sip)
433{
434 struct net *net = dev_net(in_dev->dev);
435 int scope = RT_SCOPE_LINK;
436
437 switch (IN_DEV_ARP_ACCEPT(in_dev)) {
438 case 0: /* Don't create new entries from garp */
439 return 0;
440 case 1: /* Create new entries from garp */
441 return 1;
442 case 2: /* Create a neighbor in the arp table only if sip
443 * is in the same subnet as an address configured
444 * on the interface that received the garp message
445 */
446 return !!inet_confirm_addr(net, in_dev, sip, 0, scope);
447 default:
448 return 0;
449 }
450}
451
452static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
453{
454 struct rtable *rt;
455 int flag = 0;
456 /*unsigned long now; */
457 struct net *net = dev_net(dev);
458
459 rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev),
460 RT_SCOPE_UNIVERSE);
461 if (IS_ERR(rt))
462 return 1;
463 if (rt->dst.dev != dev) {
464 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER);
465 flag = 1;
466 }
467 ip_rt_put(rt);
468 return flag;
469}
470
471/*
472 * Check if we can use proxy ARP for this path
473 */
474static inline int arp_fwd_proxy(struct in_device *in_dev,
475 struct net_device *dev, struct rtable *rt)
476{
477 struct in_device *out_dev;
478 int imi, omi = -1;
479
480 if (rt->dst.dev == dev)
481 return 0;
482
483 if (!IN_DEV_PROXY_ARP(in_dev))
484 return 0;
485 imi = IN_DEV_MEDIUM_ID(in_dev);
486 if (imi == 0)
487 return 1;
488 if (imi == -1)
489 return 0;
490
491 /* place to check for proxy_arp for routes */
492
493 out_dev = __in_dev_get_rcu(rt->dst.dev);
494 if (out_dev)
495 omi = IN_DEV_MEDIUM_ID(out_dev);
496
497 return omi != imi && omi != -1;
498}
499
500/*
501 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
502 *
503 * RFC3069 supports proxy arp replies back to the same interface. This
504 * is done to support (ethernet) switch features, like RFC 3069, where
505 * the individual ports are not allowed to communicate with each
506 * other, BUT they are allowed to talk to the upstream router. As
507 * described in RFC 3069, it is possible to allow these hosts to
508 * communicate through the upstream router, by proxy_arp'ing.
509 *
510 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
511 *
512 * This technology is known by different names:
513 * In RFC 3069 it is called VLAN Aggregation.
514 * Cisco and Allied Telesyn call it Private VLAN.
515 * Hewlett-Packard call it Source-Port filtering or port-isolation.
516 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
517 *
518 */
519static inline int arp_fwd_pvlan(struct in_device *in_dev,
520 struct net_device *dev, struct rtable *rt,
521 __be32 sip, __be32 tip)
522{
523 /* Private VLAN is only concerned about the same ethernet segment */
524 if (rt->dst.dev != dev)
525 return 0;
526
527 /* Don't reply on self probes (often done by windowz boxes)*/
528 if (sip == tip)
529 return 0;
530
531 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
532 return 1;
533 else
534 return 0;
535}
536
537/*
538 * Interface to link layer: send routine and receive handler.
539 */
540
541/*
542 * Create an arp packet. If dest_hw is not set, we create a broadcast
543 * message.
544 */
545struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
546 struct net_device *dev, __be32 src_ip,
547 const unsigned char *dest_hw,
548 const unsigned char *src_hw,
549 const unsigned char *target_hw)
550{
551 struct sk_buff *skb;
552 struct arphdr *arp;
553 unsigned char *arp_ptr;
554 int hlen = LL_RESERVED_SPACE(dev);
555 int tlen = dev->needed_tailroom;
556
557 /*
558 * Allocate a buffer
559 */
560
561 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
562 if (!skb)
563 return NULL;
564
565 skb_reserve(skb, hlen);
566 skb_reset_network_header(skb);
567 skb_put(skb, arp_hdr_len(dev));
568 skb->dev = dev;
569 skb->protocol = htons(ETH_P_ARP);
570 if (!src_hw)
571 src_hw = dev->dev_addr;
572 if (!dest_hw)
573 dest_hw = dev->broadcast;
574
575 /* Fill the device header for the ARP frame.
576 * Note: skb->head can be changed.
577 */
578 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
579 goto out;
580
581 arp = arp_hdr(skb);
582 /*
583 * Fill out the arp protocol part.
584 *
585 * The arp hardware type should match the device type, except for FDDI,
586 * which (according to RFC 1390) should always equal 1 (Ethernet).
587 */
588 /*
589 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
590 * DIX code for the protocol. Make these device structure fields.
591 */
592 switch (dev->type) {
593 default:
594 arp->ar_hrd = htons(dev->type);
595 arp->ar_pro = htons(ETH_P_IP);
596 break;
597
598#if IS_ENABLED(CONFIG_AX25)
599 case ARPHRD_AX25:
600 arp->ar_hrd = htons(ARPHRD_AX25);
601 arp->ar_pro = htons(AX25_P_IP);
602 break;
603
604#if IS_ENABLED(CONFIG_NETROM)
605 case ARPHRD_NETROM:
606 arp->ar_hrd = htons(ARPHRD_NETROM);
607 arp->ar_pro = htons(AX25_P_IP);
608 break;
609#endif
610#endif
611
612#if IS_ENABLED(CONFIG_FDDI)
613 case ARPHRD_FDDI:
614 arp->ar_hrd = htons(ARPHRD_ETHER);
615 arp->ar_pro = htons(ETH_P_IP);
616 break;
617#endif
618 }
619
620 arp->ar_hln = dev->addr_len;
621 arp->ar_pln = 4;
622 arp->ar_op = htons(type);
623
624 arp_ptr = (unsigned char *)(arp + 1);
625
626 memcpy(arp_ptr, src_hw, dev->addr_len);
627 arp_ptr += dev->addr_len;
628 memcpy(arp_ptr, &src_ip, 4);
629 arp_ptr += 4;
630
631 switch (dev->type) {
632#if IS_ENABLED(CONFIG_FIREWIRE_NET)
633 case ARPHRD_IEEE1394:
634 break;
635#endif
636 default:
637 if (target_hw)
638 memcpy(arp_ptr, target_hw, dev->addr_len);
639 else
640 memset(arp_ptr, 0, dev->addr_len);
641 arp_ptr += dev->addr_len;
642 }
643 memcpy(arp_ptr, &dest_ip, 4);
644
645 return skb;
646
647out:
648 kfree_skb(skb);
649 return NULL;
650}
651EXPORT_SYMBOL(arp_create);
652
653static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
654{
655 return dev_queue_xmit(skb);
656}
657
658/*
659 * Send an arp packet.
660 */
661void arp_xmit(struct sk_buff *skb)
662{
663 rcu_read_lock();
664 /* Send it off, maybe filter it using firewalling first. */
665 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
666 dev_net_rcu(skb->dev), NULL, skb, NULL, skb->dev,
667 arp_xmit_finish);
668 rcu_read_unlock();
669}
670EXPORT_SYMBOL(arp_xmit);
671
672static bool arp_is_garp(struct net *net, struct net_device *dev,
673 int *addr_type, __be16 ar_op,
674 __be32 sip, __be32 tip,
675 unsigned char *sha, unsigned char *tha)
676{
677 bool is_garp = tip == sip;
678
679 /* Gratuitous ARP _replies_ also require target hwaddr to be
680 * the same as source.
681 */
682 if (is_garp && ar_op == htons(ARPOP_REPLY))
683 is_garp =
684 /* IPv4 over IEEE 1394 doesn't provide target
685 * hardware address field in its ARP payload.
686 */
687 tha &&
688 !memcmp(tha, sha, dev->addr_len);
689
690 if (is_garp) {
691 *addr_type = inet_addr_type_dev_table(net, dev, sip);
692 if (*addr_type != RTN_UNICAST)
693 is_garp = false;
694 }
695 return is_garp;
696}
697
698/*
699 * Process an arp request.
700 */
701
702static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
703{
704 struct net_device *dev = skb->dev;
705 struct in_device *in_dev = __in_dev_get_rcu(dev);
706 struct arphdr *arp;
707 unsigned char *arp_ptr;
708 struct rtable *rt;
709 unsigned char *sha;
710 unsigned char *tha = NULL;
711 __be32 sip, tip;
712 u16 dev_type = dev->type;
713 int addr_type;
714 struct neighbour *n;
715 struct dst_entry *reply_dst = NULL;
716 bool is_garp = false;
717
718 /* arp_rcv below verifies the ARP header and verifies the device
719 * is ARP'able.
720 */
721
722 if (!in_dev)
723 goto out_free_skb;
724
725 arp = arp_hdr(skb);
726
727 switch (dev_type) {
728 default:
729 if (arp->ar_pro != htons(ETH_P_IP) ||
730 htons(dev_type) != arp->ar_hrd)
731 goto out_free_skb;
732 break;
733 case ARPHRD_ETHER:
734 case ARPHRD_FDDI:
735 case ARPHRD_IEEE802:
736 /*
737 * ETHERNET, and Fibre Channel (which are IEEE 802
738 * devices, according to RFC 2625) devices will accept ARP
739 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
740 * This is the case also of FDDI, where the RFC 1390 says that
741 * FDDI devices should accept ARP hardware of (1) Ethernet,
742 * however, to be more robust, we'll accept both 1 (Ethernet)
743 * or 6 (IEEE 802.2)
744 */
745 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
746 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
747 arp->ar_pro != htons(ETH_P_IP))
748 goto out_free_skb;
749 break;
750 case ARPHRD_AX25:
751 if (arp->ar_pro != htons(AX25_P_IP) ||
752 arp->ar_hrd != htons(ARPHRD_AX25))
753 goto out_free_skb;
754 break;
755 case ARPHRD_NETROM:
756 if (arp->ar_pro != htons(AX25_P_IP) ||
757 arp->ar_hrd != htons(ARPHRD_NETROM))
758 goto out_free_skb;
759 break;
760 }
761
762 /* Understand only these message types */
763
764 if (arp->ar_op != htons(ARPOP_REPLY) &&
765 arp->ar_op != htons(ARPOP_REQUEST))
766 goto out_free_skb;
767
768/*
769 * Extract fields
770 */
771 arp_ptr = (unsigned char *)(arp + 1);
772 sha = arp_ptr;
773 arp_ptr += dev->addr_len;
774 memcpy(&sip, arp_ptr, 4);
775 arp_ptr += 4;
776 switch (dev_type) {
777#if IS_ENABLED(CONFIG_FIREWIRE_NET)
778 case ARPHRD_IEEE1394:
779 break;
780#endif
781 default:
782 tha = arp_ptr;
783 arp_ptr += dev->addr_len;
784 }
785 memcpy(&tip, arp_ptr, 4);
786/*
787 * Check for bad requests for 127.x.x.x and requests for multicast
788 * addresses. If this is one such, delete it.
789 */
790 if (ipv4_is_multicast(tip) ||
791 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
792 goto out_free_skb;
793
794 /*
795 * For some 802.11 wireless deployments (and possibly other networks),
796 * there will be an ARP proxy and gratuitous ARP frames are attacks
797 * and thus should not be accepted.
798 */
799 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
800 goto out_free_skb;
801
802/*
803 * Special case: We must set Frame Relay source Q.922 address
804 */
805 if (dev_type == ARPHRD_DLCI)
806 sha = dev->broadcast;
807
808/*
809 * Process entry. The idea here is we want to send a reply if it is a
810 * request for us or if it is a request for someone else that we hold
811 * a proxy for. We want to add an entry to our cache if it is a reply
812 * to us or if it is a request for our address.
813 * (The assumption for this last is that if someone is requesting our
814 * address, they are probably intending to talk to us, so it saves time
815 * if we cache their address. Their address is also probably not in
816 * our cache, since ours is not in their cache.)
817 *
818 * Putting this another way, we only care about replies if they are to
819 * us, in which case we add them to the cache. For requests, we care
820 * about those for us and those for our proxies. We reply to both,
821 * and in the case of requests for us we add the requester to the arp
822 * cache.
823 */
824
825 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
826 reply_dst = (struct dst_entry *)
827 iptunnel_metadata_reply(skb_metadata_dst(skb),
828 GFP_ATOMIC);
829
830 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
831 if (sip == 0) {
832 if (arp->ar_op == htons(ARPOP_REQUEST) &&
833 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
834 !arp_ignore(in_dev, sip, tip))
835 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
836 sha, dev->dev_addr, sha, reply_dst);
837 goto out_consume_skb;
838 }
839
840 if (arp->ar_op == htons(ARPOP_REQUEST) &&
841 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
842
843 rt = skb_rtable(skb);
844 addr_type = rt->rt_type;
845
846 if (addr_type == RTN_LOCAL) {
847 int dont_send;
848
849 dont_send = arp_ignore(in_dev, sip, tip);
850 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
851 dont_send = arp_filter(sip, tip, dev);
852 if (!dont_send) {
853 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
854 if (n) {
855 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
856 sip, dev, tip, sha,
857 dev->dev_addr, sha,
858 reply_dst);
859 neigh_release(n);
860 }
861 }
862 goto out_consume_skb;
863 } else if (IN_DEV_FORWARD(in_dev)) {
864 if (addr_type == RTN_UNICAST &&
865 (arp_fwd_proxy(in_dev, dev, rt) ||
866 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
867 (rt->dst.dev != dev &&
868 pneigh_lookup(&arp_tbl, net, &tip, dev)))) {
869 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
870 if (n)
871 neigh_release(n);
872
873 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
874 skb->pkt_type == PACKET_HOST ||
875 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
876 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
877 sip, dev, tip, sha,
878 dev->dev_addr, sha,
879 reply_dst);
880 } else {
881 pneigh_enqueue(&arp_tbl,
882 in_dev->arp_parms, skb);
883 goto out_free_dst;
884 }
885 goto out_consume_skb;
886 }
887 }
888 }
889
890 /* Update our ARP tables */
891
892 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
893
894 addr_type = -1;
895 if (n || arp_accept(in_dev, sip)) {
896 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op,
897 sip, tip, sha, tha);
898 }
899
900 if (arp_accept(in_dev, sip)) {
901 /* Unsolicited ARP is not accepted by default.
902 It is possible, that this option should be enabled for some
903 devices (strip is candidate)
904 */
905 if (!n &&
906 (is_garp ||
907 (arp->ar_op == htons(ARPOP_REPLY) &&
908 (addr_type == RTN_UNICAST ||
909 (addr_type < 0 &&
910 /* postpone calculation to as late as possible */
911 inet_addr_type_dev_table(net, dev, sip) ==
912 RTN_UNICAST)))))
913 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
914 }
915
916 if (n) {
917 int state = NUD_REACHABLE;
918 int override;
919
920 /* If several different ARP replies follows back-to-back,
921 use the FIRST one. It is possible, if several proxy
922 agents are active. Taking the first reply prevents
923 arp trashing and chooses the fastest router.
924 */
925 override = time_after(jiffies,
926 n->updated +
927 NEIGH_VAR(n->parms, LOCKTIME)) ||
928 is_garp;
929
930 /* Broadcast replies and request packets
931 do not assert neighbour reachability.
932 */
933 if (arp->ar_op != htons(ARPOP_REPLY) ||
934 skb->pkt_type != PACKET_HOST)
935 state = NUD_STALE;
936 neigh_update(n, sha, state,
937 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0);
938 neigh_release(n);
939 }
940
941out_consume_skb:
942 consume_skb(skb);
943
944out_free_dst:
945 dst_release(reply_dst);
946 return NET_RX_SUCCESS;
947
948out_free_skb:
949 kfree_skb(skb);
950 return NET_RX_DROP;
951}
952
953static void parp_redo(struct sk_buff *skb)
954{
955 arp_process(dev_net(skb->dev), NULL, skb);
956}
957
958static int arp_is_multicast(const void *pkey)
959{
960 return ipv4_is_multicast(*((__be32 *)pkey));
961}
962
963/*
964 * Receive an arp request from the device layer.
965 */
966
967static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
968 struct packet_type *pt, struct net_device *orig_dev)
969{
970 enum skb_drop_reason drop_reason;
971 const struct arphdr *arp;
972
973 /* do not tweak dropwatch on an ARP we will ignore */
974 if (dev->flags & IFF_NOARP ||
975 skb->pkt_type == PACKET_OTHERHOST ||
976 skb->pkt_type == PACKET_LOOPBACK)
977 goto consumeskb;
978
979 skb = skb_share_check(skb, GFP_ATOMIC);
980 if (!skb)
981 goto out_of_mem;
982
983 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
984 drop_reason = pskb_may_pull_reason(skb, arp_hdr_len(dev));
985 if (drop_reason != SKB_NOT_DROPPED_YET)
986 goto freeskb;
987
988 arp = arp_hdr(skb);
989 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) {
990 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
991 goto freeskb;
992 }
993
994 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
995
996 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
997 dev_net(dev), NULL, skb, dev, NULL,
998 arp_process);
999
1000consumeskb:
1001 consume_skb(skb);
1002 return NET_RX_SUCCESS;
1003freeskb:
1004 kfree_skb_reason(skb, drop_reason);
1005out_of_mem:
1006 return NET_RX_DROP;
1007}
1008
1009/*
1010 * User level interface (ioctl)
1011 */
1012
1013static struct net_device *arp_req_dev_by_name(struct net *net, struct arpreq *r,
1014 bool getarp)
1015{
1016 struct net_device *dev;
1017
1018 if (getarp)
1019 dev = dev_get_by_name_rcu(net, r->arp_dev);
1020 else
1021 dev = __dev_get_by_name(net, r->arp_dev);
1022 if (!dev)
1023 return ERR_PTR(-ENODEV);
1024
1025 /* Mmmm... It is wrong... ARPHRD_NETROM == 0 */
1026 if (!r->arp_ha.sa_family)
1027 r->arp_ha.sa_family = dev->type;
1028
1029 if ((r->arp_flags & ATF_COM) && r->arp_ha.sa_family != dev->type)
1030 return ERR_PTR(-EINVAL);
1031
1032 return dev;
1033}
1034
1035static struct net_device *arp_req_dev(struct net *net, struct arpreq *r)
1036{
1037 struct net_device *dev;
1038 struct rtable *rt;
1039 __be32 ip;
1040
1041 if (r->arp_dev[0])
1042 return arp_req_dev_by_name(net, r, false);
1043
1044 if (r->arp_flags & ATF_PUBL)
1045 return NULL;
1046
1047 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1048
1049 rt = ip_route_output(net, ip, 0, 0, 0, RT_SCOPE_LINK);
1050 if (IS_ERR(rt))
1051 return ERR_CAST(rt);
1052
1053 dev = rt->dst.dev;
1054 ip_rt_put(rt);
1055
1056 if (!dev)
1057 return ERR_PTR(-EINVAL);
1058
1059 return dev;
1060}
1061
1062/*
1063 * Set (create) an ARP cache entry.
1064 */
1065
1066static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
1067{
1068 if (!dev) {
1069 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
1070 return 0;
1071 }
1072 if (__in_dev_get_rtnl_net(dev)) {
1073 IN_DEV_CONF_SET(__in_dev_get_rtnl_net(dev), PROXY_ARP, on);
1074 return 0;
1075 }
1076 return -ENXIO;
1077}
1078
1079static int arp_req_set_public(struct net *net, struct arpreq *r,
1080 struct net_device *dev)
1081{
1082 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1083
1084 if (!dev && (r->arp_flags & ATF_COM)) {
1085 dev = dev_getbyhwaddr(net, r->arp_ha.sa_family,
1086 r->arp_ha.sa_data);
1087 if (!dev)
1088 return -ENODEV;
1089 }
1090 if (mask) {
1091 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1092
1093 return pneigh_create(&arp_tbl, net, &ip, dev, 0, 0, false);
1094 }
1095
1096 return arp_req_set_proxy(net, dev, 1);
1097}
1098
1099static int arp_req_set(struct net *net, struct arpreq *r)
1100{
1101 struct neighbour *neigh;
1102 struct net_device *dev;
1103 __be32 ip;
1104 int err;
1105
1106 dev = arp_req_dev(net, r);
1107 if (IS_ERR(dev))
1108 return PTR_ERR(dev);
1109
1110 if (r->arp_flags & ATF_PUBL)
1111 return arp_req_set_public(net, r, dev);
1112
1113 switch (dev->type) {
1114#if IS_ENABLED(CONFIG_FDDI)
1115 case ARPHRD_FDDI:
1116 /*
1117 * According to RFC 1390, FDDI devices should accept ARP
1118 * hardware types of 1 (Ethernet). However, to be more
1119 * robust, we'll accept hardware types of either 1 (Ethernet)
1120 * or 6 (IEEE 802.2).
1121 */
1122 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1123 r->arp_ha.sa_family != ARPHRD_ETHER &&
1124 r->arp_ha.sa_family != ARPHRD_IEEE802)
1125 return -EINVAL;
1126 break;
1127#endif
1128 default:
1129 if (r->arp_ha.sa_family != dev->type)
1130 return -EINVAL;
1131 break;
1132 }
1133
1134 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1135
1136 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1137 err = PTR_ERR(neigh);
1138 if (!IS_ERR(neigh)) {
1139 unsigned int state = NUD_STALE;
1140
1141 if (r->arp_flags & ATF_PERM) {
1142 r->arp_flags |= ATF_COM;
1143 state = NUD_PERMANENT;
1144 }
1145
1146 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1147 r->arp_ha.sa_data : NULL, state,
1148 NEIGH_UPDATE_F_OVERRIDE |
1149 NEIGH_UPDATE_F_ADMIN, 0);
1150 neigh_release(neigh);
1151 }
1152 return err;
1153}
1154
1155static unsigned int arp_state_to_flags(struct neighbour *neigh)
1156{
1157 if (neigh->nud_state&NUD_PERMANENT)
1158 return ATF_PERM | ATF_COM;
1159 else if (neigh->nud_state&NUD_VALID)
1160 return ATF_COM;
1161 else
1162 return 0;
1163}
1164
1165/*
1166 * Get an ARP cache entry.
1167 */
1168
1169static int arp_req_get(struct net *net, struct arpreq *r)
1170{
1171 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1172 struct neighbour *neigh;
1173 struct net_device *dev;
1174
1175 if (!r->arp_dev[0])
1176 return -ENODEV;
1177
1178 dev = arp_req_dev_by_name(net, r, true);
1179 if (IS_ERR(dev))
1180 return PTR_ERR(dev);
1181
1182 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1183 if (!neigh)
1184 return -ENXIO;
1185
1186 if (READ_ONCE(neigh->nud_state) & NUD_NOARP) {
1187 neigh_release(neigh);
1188 return -ENXIO;
1189 }
1190
1191 read_lock_bh(&neigh->lock);
1192 memcpy(r->arp_ha.sa_data, neigh->ha,
1193 min(dev->addr_len, sizeof(r->arp_ha.sa_data)));
1194 r->arp_flags = arp_state_to_flags(neigh);
1195 read_unlock_bh(&neigh->lock);
1196
1197 neigh_release(neigh);
1198
1199 r->arp_ha.sa_family = dev->type;
1200 netdev_copy_name(dev, r->arp_dev);
1201
1202 return 0;
1203}
1204
1205int arp_invalidate(struct net_device *dev, __be32 ip, bool force)
1206{
1207 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1208 int err = -ENXIO;
1209 struct neigh_table *tbl = &arp_tbl;
1210
1211 if (neigh) {
1212 if ((READ_ONCE(neigh->nud_state) & NUD_VALID) && !force) {
1213 neigh_release(neigh);
1214 return 0;
1215 }
1216
1217 if (READ_ONCE(neigh->nud_state) & ~NUD_NOARP)
1218 err = neigh_update(neigh, NULL, NUD_FAILED,
1219 NEIGH_UPDATE_F_OVERRIDE|
1220 NEIGH_UPDATE_F_ADMIN, 0);
1221 spin_lock_bh(&tbl->lock);
1222 neigh_release(neigh);
1223 neigh_remove_one(neigh);
1224 spin_unlock_bh(&tbl->lock);
1225 }
1226
1227 return err;
1228}
1229
1230static int arp_req_delete_public(struct net *net, struct arpreq *r,
1231 struct net_device *dev)
1232{
1233 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1234
1235 if (mask) {
1236 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1237
1238 return pneigh_delete(&arp_tbl, net, &ip, dev);
1239 }
1240
1241 return arp_req_set_proxy(net, dev, 0);
1242}
1243
1244static int arp_req_delete(struct net *net, struct arpreq *r)
1245{
1246 struct net_device *dev;
1247 __be32 ip;
1248
1249 dev = arp_req_dev(net, r);
1250 if (IS_ERR(dev))
1251 return PTR_ERR(dev);
1252
1253 if (r->arp_flags & ATF_PUBL)
1254 return arp_req_delete_public(net, r, dev);
1255
1256 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1257
1258 return arp_invalidate(dev, ip, true);
1259}
1260
1261/*
1262 * Handle an ARP layer I/O control request.
1263 */
1264
1265int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1266{
1267 struct arpreq r;
1268 __be32 *netmask;
1269 int err;
1270
1271 switch (cmd) {
1272 case SIOCDARP:
1273 case SIOCSARP:
1274 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1275 return -EPERM;
1276 fallthrough;
1277 case SIOCGARP:
1278 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1279 if (err)
1280 return -EFAULT;
1281 r.arp_dev[IFNAMSIZ - 1] = '\0';
1282 break;
1283 default:
1284 return -EINVAL;
1285 }
1286
1287 if (r.arp_pa.sa_family != AF_INET)
1288 return -EPFNOSUPPORT;
1289
1290 if (!(r.arp_flags & ATF_PUBL) &&
1291 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1292 return -EINVAL;
1293
1294 netmask = &((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr;
1295 if (!(r.arp_flags & ATF_NETMASK))
1296 *netmask = htonl(0xFFFFFFFFUL);
1297 else if (*netmask && *netmask != htonl(0xFFFFFFFFUL))
1298 return -EINVAL;
1299
1300 switch (cmd) {
1301 case SIOCDARP:
1302 rtnl_net_lock(net);
1303 err = arp_req_delete(net, &r);
1304 rtnl_net_unlock(net);
1305 break;
1306 case SIOCSARP:
1307 rtnl_net_lock(net);
1308 err = arp_req_set(net, &r);
1309 rtnl_net_unlock(net);
1310 break;
1311 case SIOCGARP:
1312 rcu_read_lock();
1313 err = arp_req_get(net, &r);
1314 rcu_read_unlock();
1315
1316 if (!err && copy_to_user(arg, &r, sizeof(r)))
1317 err = -EFAULT;
1318 break;
1319 }
1320
1321 return err;
1322}
1323
1324static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1325 void *ptr)
1326{
1327 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1328 struct netdev_notifier_change_info *change_info;
1329 struct in_device *in_dev;
1330 bool evict_nocarrier;
1331
1332 switch (event) {
1333 case NETDEV_CHANGEADDR:
1334 neigh_changeaddr(&arp_tbl, dev);
1335 rt_cache_flush(dev_net(dev));
1336 break;
1337 case NETDEV_CHANGE:
1338 change_info = ptr;
1339 if (change_info->flags_changed & IFF_NOARP)
1340 neigh_changeaddr(&arp_tbl, dev);
1341
1342 in_dev = __in_dev_get_rtnl(dev);
1343 if (!in_dev)
1344 evict_nocarrier = true;
1345 else
1346 evict_nocarrier = IN_DEV_ARP_EVICT_NOCARRIER(in_dev);
1347
1348 if (evict_nocarrier && !netif_carrier_ok(dev))
1349 neigh_carrier_down(&arp_tbl, dev);
1350 break;
1351 default:
1352 break;
1353 }
1354
1355 return NOTIFY_DONE;
1356}
1357
1358static struct notifier_block arp_netdev_notifier = {
1359 .notifier_call = arp_netdev_event,
1360};
1361
1362/* Note, that it is not on notifier chain.
1363 It is necessary, that this routine was called after route cache will be
1364 flushed.
1365 */
1366void arp_ifdown(struct net_device *dev)
1367{
1368 neigh_ifdown(&arp_tbl, dev);
1369}
1370
1371
1372/*
1373 * Called once on startup.
1374 */
1375
1376static struct packet_type arp_packet_type __read_mostly = {
1377 .type = cpu_to_be16(ETH_P_ARP),
1378 .func = arp_rcv,
1379};
1380
1381#ifdef CONFIG_PROC_FS
1382#if IS_ENABLED(CONFIG_AX25)
1383
1384/*
1385 * ax25 -> ASCII conversion
1386 */
1387static void ax2asc2(ax25_address *a, char *buf)
1388{
1389 char c, *s;
1390 int n;
1391
1392 for (n = 0, s = buf; n < 6; n++) {
1393 c = (a->ax25_call[n] >> 1) & 0x7F;
1394
1395 if (c != ' ')
1396 *s++ = c;
1397 }
1398
1399 *s++ = '-';
1400 n = (a->ax25_call[6] >> 1) & 0x0F;
1401 if (n > 9) {
1402 *s++ = '1';
1403 n -= 10;
1404 }
1405
1406 *s++ = n + '0';
1407 *s++ = '\0';
1408
1409 if (*buf == '\0' || *buf == '-') {
1410 buf[0] = '*';
1411 buf[1] = '\0';
1412 }
1413}
1414#endif /* CONFIG_AX25 */
1415
1416#define HBUFFERLEN 30
1417
1418static void arp_format_neigh_entry(struct seq_file *seq,
1419 struct neighbour *n)
1420{
1421 char hbuffer[HBUFFERLEN];
1422 int k, j;
1423 char tbuf[16];
1424 struct net_device *dev = n->dev;
1425 int hatype = dev->type;
1426
1427 read_lock(&n->lock);
1428 /* Convert hardware address to XX:XX:XX:XX ... form. */
1429#if IS_ENABLED(CONFIG_AX25)
1430 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1431 ax2asc2((ax25_address *)n->ha, hbuffer);
1432 else {
1433#endif
1434 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1435 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1436 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1437 hbuffer[k++] = ':';
1438 }
1439 if (k != 0)
1440 --k;
1441 hbuffer[k] = 0;
1442#if IS_ENABLED(CONFIG_AX25)
1443 }
1444#endif
1445 sprintf(tbuf, "%pI4", n->primary_key);
1446 seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n",
1447 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1448 read_unlock(&n->lock);
1449}
1450
1451static void arp_format_pneigh_entry(struct seq_file *seq,
1452 struct pneigh_entry *n)
1453{
1454 struct net_device *dev = n->dev;
1455 int hatype = dev ? dev->type : 0;
1456 char tbuf[16];
1457
1458 sprintf(tbuf, "%pI4", n->key);
1459 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1460 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1461 dev ? dev->name : "*");
1462}
1463
1464static int arp_seq_show(struct seq_file *seq, void *v)
1465{
1466 if (v == SEQ_START_TOKEN) {
1467 seq_puts(seq, "IP address HW type Flags "
1468 "HW address Mask Device\n");
1469 } else {
1470 struct neigh_seq_state *state = seq->private;
1471
1472 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1473 arp_format_pneigh_entry(seq, v);
1474 else
1475 arp_format_neigh_entry(seq, v);
1476 }
1477
1478 return 0;
1479}
1480
1481static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1482{
1483 /* Don't want to confuse "arp -a" w/ magic entries,
1484 * so we tell the generic iterator to skip NUD_NOARP.
1485 */
1486 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1487}
1488
1489static const struct seq_operations arp_seq_ops = {
1490 .start = arp_seq_start,
1491 .next = neigh_seq_next,
1492 .stop = neigh_seq_stop,
1493 .show = arp_seq_show,
1494};
1495#endif /* CONFIG_PROC_FS */
1496
1497static int __net_init arp_net_init(struct net *net)
1498{
1499 if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops,
1500 sizeof(struct neigh_seq_state)))
1501 return -ENOMEM;
1502 return 0;
1503}
1504
1505static void __net_exit arp_net_exit(struct net *net)
1506{
1507 remove_proc_entry("arp", net->proc_net);
1508}
1509
1510static struct pernet_operations arp_net_ops = {
1511 .init = arp_net_init,
1512 .exit = arp_net_exit,
1513};
1514
1515void __init arp_init(void)
1516{
1517 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
1518
1519 dev_add_pack(&arp_packet_type);
1520 register_pernet_subsys(&arp_net_ops);
1521#ifdef CONFIG_SYSCTL
1522 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1523#endif
1524 register_netdevice_notifier(&arp_netdev_notifier);
1525}