Loading...
1/* linux/net/ipv4/arp.c
2 *
3 * Copyright (C) 1994 by Florian La Roche
4 *
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
8 * address).
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Fixes:
16 * Alan Cox : Removed the Ethernet assumptions in
17 * Florian's code
18 * Alan Cox : Fixed some small errors in the ARP
19 * logic
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
40 * Craig Schlenter : Don't modify permanent entry
41 * during arp_rcv.
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
44 * eg intelligent arp probing and
45 * generation
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
51 * Jonathan Layes : Added arpd support through kerneld
52 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
58 * Alan Cox : Took the AP1000 nasty FDDI hack and
59 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
61 * one in...
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
73 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
74 */
75
76#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
77
78#include <linux/module.h>
79#include <linux/types.h>
80#include <linux/string.h>
81#include <linux/kernel.h>
82#include <linux/capability.h>
83#include <linux/socket.h>
84#include <linux/sockios.h>
85#include <linux/errno.h>
86#include <linux/in.h>
87#include <linux/mm.h>
88#include <linux/inet.h>
89#include <linux/inetdevice.h>
90#include <linux/netdevice.h>
91#include <linux/etherdevice.h>
92#include <linux/fddidevice.h>
93#include <linux/if_arp.h>
94#include <linux/skbuff.h>
95#include <linux/proc_fs.h>
96#include <linux/seq_file.h>
97#include <linux/stat.h>
98#include <linux/init.h>
99#include <linux/net.h>
100#include <linux/rcupdate.h>
101#include <linux/slab.h>
102#ifdef CONFIG_SYSCTL
103#include <linux/sysctl.h>
104#endif
105
106#include <net/net_namespace.h>
107#include <net/ip.h>
108#include <net/icmp.h>
109#include <net/route.h>
110#include <net/protocol.h>
111#include <net/tcp.h>
112#include <net/sock.h>
113#include <net/arp.h>
114#include <net/ax25.h>
115#include <net/netrom.h>
116#include <net/dst_metadata.h>
117#include <net/ip_tunnels.h>
118
119#include <linux/uaccess.h>
120
121#include <linux/netfilter_arp.h>
122
123/*
124 * Interface to generic neighbour cache.
125 */
126static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
127static bool arp_key_eq(const struct neighbour *n, const void *pkey);
128static int arp_constructor(struct neighbour *neigh);
129static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
130static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
131static void parp_redo(struct sk_buff *skb);
132
133static const struct neigh_ops arp_generic_ops = {
134 .family = AF_INET,
135 .solicit = arp_solicit,
136 .error_report = arp_error_report,
137 .output = neigh_resolve_output,
138 .connected_output = neigh_connected_output,
139};
140
141static const struct neigh_ops arp_hh_ops = {
142 .family = AF_INET,
143 .solicit = arp_solicit,
144 .error_report = arp_error_report,
145 .output = neigh_resolve_output,
146 .connected_output = neigh_resolve_output,
147};
148
149static const struct neigh_ops arp_direct_ops = {
150 .family = AF_INET,
151 .output = neigh_direct_output,
152 .connected_output = neigh_direct_output,
153};
154
155struct neigh_table arp_tbl = {
156 .family = AF_INET,
157 .key_len = 4,
158 .protocol = cpu_to_be16(ETH_P_IP),
159 .hash = arp_hash,
160 .key_eq = arp_key_eq,
161 .constructor = arp_constructor,
162 .proxy_redo = parp_redo,
163 .id = "arp_cache",
164 .parms = {
165 .tbl = &arp_tbl,
166 .reachable_time = 30 * HZ,
167 .data = {
168 [NEIGH_VAR_MCAST_PROBES] = 3,
169 [NEIGH_VAR_UCAST_PROBES] = 3,
170 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
171 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
172 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
173 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
174 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
175 [NEIGH_VAR_PROXY_QLEN] = 64,
176 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
177 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
178 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
179 },
180 },
181 .gc_interval = 30 * HZ,
182 .gc_thresh1 = 128,
183 .gc_thresh2 = 512,
184 .gc_thresh3 = 1024,
185};
186EXPORT_SYMBOL(arp_tbl);
187
188int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
189{
190 switch (dev->type) {
191 case ARPHRD_ETHER:
192 case ARPHRD_FDDI:
193 case ARPHRD_IEEE802:
194 ip_eth_mc_map(addr, haddr);
195 return 0;
196 case ARPHRD_INFINIBAND:
197 ip_ib_mc_map(addr, dev->broadcast, haddr);
198 return 0;
199 case ARPHRD_IPGRE:
200 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
201 return 0;
202 default:
203 if (dir) {
204 memcpy(haddr, dev->broadcast, dev->addr_len);
205 return 0;
206 }
207 }
208 return -EINVAL;
209}
210
211
212static u32 arp_hash(const void *pkey,
213 const struct net_device *dev,
214 __u32 *hash_rnd)
215{
216 return arp_hashfn(pkey, dev, hash_rnd);
217}
218
219static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
220{
221 return neigh_key_eq32(neigh, pkey);
222}
223
224static int arp_constructor(struct neighbour *neigh)
225{
226 __be32 addr;
227 struct net_device *dev = neigh->dev;
228 struct in_device *in_dev;
229 struct neigh_parms *parms;
230 u32 inaddr_any = INADDR_ANY;
231
232 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
233 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len);
234
235 addr = *(__be32 *)neigh->primary_key;
236 rcu_read_lock();
237 in_dev = __in_dev_get_rcu(dev);
238 if (!in_dev) {
239 rcu_read_unlock();
240 return -EINVAL;
241 }
242
243 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
244
245 parms = in_dev->arp_parms;
246 __neigh_parms_put(neigh->parms);
247 neigh->parms = neigh_parms_clone(parms);
248 rcu_read_unlock();
249
250 if (!dev->header_ops) {
251 neigh->nud_state = NUD_NOARP;
252 neigh->ops = &arp_direct_ops;
253 neigh->output = neigh_direct_output;
254 } else {
255 /* Good devices (checked by reading texts, but only Ethernet is
256 tested)
257
258 ARPHRD_ETHER: (ethernet, apfddi)
259 ARPHRD_FDDI: (fddi)
260 ARPHRD_IEEE802: (tr)
261 ARPHRD_METRICOM: (strip)
262 ARPHRD_ARCNET:
263 etc. etc. etc.
264
265 ARPHRD_IPDDP will also work, if author repairs it.
266 I did not it, because this driver does not work even
267 in old paradigm.
268 */
269
270 if (neigh->type == RTN_MULTICAST) {
271 neigh->nud_state = NUD_NOARP;
272 arp_mc_map(addr, neigh->ha, dev, 1);
273 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
274 neigh->nud_state = NUD_NOARP;
275 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
276 } else if (neigh->type == RTN_BROADCAST ||
277 (dev->flags & IFF_POINTOPOINT)) {
278 neigh->nud_state = NUD_NOARP;
279 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
280 }
281
282 if (dev->header_ops->cache)
283 neigh->ops = &arp_hh_ops;
284 else
285 neigh->ops = &arp_generic_ops;
286
287 if (neigh->nud_state & NUD_VALID)
288 neigh->output = neigh->ops->connected_output;
289 else
290 neigh->output = neigh->ops->output;
291 }
292 return 0;
293}
294
295static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
296{
297 dst_link_failure(skb);
298 kfree_skb(skb);
299}
300
301/* Create and send an arp packet. */
302static void arp_send_dst(int type, int ptype, __be32 dest_ip,
303 struct net_device *dev, __be32 src_ip,
304 const unsigned char *dest_hw,
305 const unsigned char *src_hw,
306 const unsigned char *target_hw,
307 struct dst_entry *dst)
308{
309 struct sk_buff *skb;
310
311 /* arp on this interface. */
312 if (dev->flags & IFF_NOARP)
313 return;
314
315 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
316 dest_hw, src_hw, target_hw);
317 if (!skb)
318 return;
319
320 skb_dst_set(skb, dst_clone(dst));
321 arp_xmit(skb);
322}
323
324void arp_send(int type, int ptype, __be32 dest_ip,
325 struct net_device *dev, __be32 src_ip,
326 const unsigned char *dest_hw, const unsigned char *src_hw,
327 const unsigned char *target_hw)
328{
329 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
330 target_hw, NULL);
331}
332EXPORT_SYMBOL(arp_send);
333
334static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
335{
336 __be32 saddr = 0;
337 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
338 struct net_device *dev = neigh->dev;
339 __be32 target = *(__be32 *)neigh->primary_key;
340 int probes = atomic_read(&neigh->probes);
341 struct in_device *in_dev;
342 struct dst_entry *dst = NULL;
343
344 rcu_read_lock();
345 in_dev = __in_dev_get_rcu(dev);
346 if (!in_dev) {
347 rcu_read_unlock();
348 return;
349 }
350 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
351 default:
352 case 0: /* By default announce any local IP */
353 if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
354 ip_hdr(skb)->saddr) == RTN_LOCAL)
355 saddr = ip_hdr(skb)->saddr;
356 break;
357 case 1: /* Restrict announcements of saddr in same subnet */
358 if (!skb)
359 break;
360 saddr = ip_hdr(skb)->saddr;
361 if (inet_addr_type_dev_table(dev_net(dev), dev,
362 saddr) == RTN_LOCAL) {
363 /* saddr should be known to target */
364 if (inet_addr_onlink(in_dev, target, saddr))
365 break;
366 }
367 saddr = 0;
368 break;
369 case 2: /* Avoid secondary IPs, get a primary/preferred one */
370 break;
371 }
372 rcu_read_unlock();
373
374 if (!saddr)
375 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
376
377 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
378 if (probes < 0) {
379 if (!(neigh->nud_state & NUD_VALID))
380 pr_debug("trying to ucast probe in NUD_INVALID\n");
381 neigh_ha_snapshot(dst_ha, neigh, dev);
382 dst_hw = dst_ha;
383 } else {
384 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
385 if (probes < 0) {
386 neigh_app_ns(neigh);
387 return;
388 }
389 }
390
391 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
392 dst = skb_dst(skb);
393 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
394 dst_hw, dev->dev_addr, NULL, dst);
395}
396
397static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
398{
399 struct net *net = dev_net(in_dev->dev);
400 int scope;
401
402 switch (IN_DEV_ARP_IGNORE(in_dev)) {
403 case 0: /* Reply, the tip is already validated */
404 return 0;
405 case 1: /* Reply only if tip is configured on the incoming interface */
406 sip = 0;
407 scope = RT_SCOPE_HOST;
408 break;
409 case 2: /*
410 * Reply only if tip is configured on the incoming interface
411 * and is in same subnet as sip
412 */
413 scope = RT_SCOPE_HOST;
414 break;
415 case 3: /* Do not reply for scope host addresses */
416 sip = 0;
417 scope = RT_SCOPE_LINK;
418 in_dev = NULL;
419 break;
420 case 4: /* Reserved */
421 case 5:
422 case 6:
423 case 7:
424 return 0;
425 case 8: /* Do not reply */
426 return 1;
427 default:
428 return 0;
429 }
430 return !inet_confirm_addr(net, in_dev, sip, tip, scope);
431}
432
433static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
434{
435 struct rtable *rt;
436 int flag = 0;
437 /*unsigned long now; */
438 struct net *net = dev_net(dev);
439
440 rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev));
441 if (IS_ERR(rt))
442 return 1;
443 if (rt->dst.dev != dev) {
444 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER);
445 flag = 1;
446 }
447 ip_rt_put(rt);
448 return flag;
449}
450
451/*
452 * Check if we can use proxy ARP for this path
453 */
454static inline int arp_fwd_proxy(struct in_device *in_dev,
455 struct net_device *dev, struct rtable *rt)
456{
457 struct in_device *out_dev;
458 int imi, omi = -1;
459
460 if (rt->dst.dev == dev)
461 return 0;
462
463 if (!IN_DEV_PROXY_ARP(in_dev))
464 return 0;
465 imi = IN_DEV_MEDIUM_ID(in_dev);
466 if (imi == 0)
467 return 1;
468 if (imi == -1)
469 return 0;
470
471 /* place to check for proxy_arp for routes */
472
473 out_dev = __in_dev_get_rcu(rt->dst.dev);
474 if (out_dev)
475 omi = IN_DEV_MEDIUM_ID(out_dev);
476
477 return omi != imi && omi != -1;
478}
479
480/*
481 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
482 *
483 * RFC3069 supports proxy arp replies back to the same interface. This
484 * is done to support (ethernet) switch features, like RFC 3069, where
485 * the individual ports are not allowed to communicate with each
486 * other, BUT they are allowed to talk to the upstream router. As
487 * described in RFC 3069, it is possible to allow these hosts to
488 * communicate through the upstream router, by proxy_arp'ing.
489 *
490 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
491 *
492 * This technology is known by different names:
493 * In RFC 3069 it is called VLAN Aggregation.
494 * Cisco and Allied Telesyn call it Private VLAN.
495 * Hewlett-Packard call it Source-Port filtering or port-isolation.
496 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
497 *
498 */
499static inline int arp_fwd_pvlan(struct in_device *in_dev,
500 struct net_device *dev, struct rtable *rt,
501 __be32 sip, __be32 tip)
502{
503 /* Private VLAN is only concerned about the same ethernet segment */
504 if (rt->dst.dev != dev)
505 return 0;
506
507 /* Don't reply on self probes (often done by windowz boxes)*/
508 if (sip == tip)
509 return 0;
510
511 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
512 return 1;
513 else
514 return 0;
515}
516
517/*
518 * Interface to link layer: send routine and receive handler.
519 */
520
521/*
522 * Create an arp packet. If dest_hw is not set, we create a broadcast
523 * message.
524 */
525struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
526 struct net_device *dev, __be32 src_ip,
527 const unsigned char *dest_hw,
528 const unsigned char *src_hw,
529 const unsigned char *target_hw)
530{
531 struct sk_buff *skb;
532 struct arphdr *arp;
533 unsigned char *arp_ptr;
534 int hlen = LL_RESERVED_SPACE(dev);
535 int tlen = dev->needed_tailroom;
536
537 /*
538 * Allocate a buffer
539 */
540
541 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
542 if (!skb)
543 return NULL;
544
545 skb_reserve(skb, hlen);
546 skb_reset_network_header(skb);
547 arp = skb_put(skb, arp_hdr_len(dev));
548 skb->dev = dev;
549 skb->protocol = htons(ETH_P_ARP);
550 if (!src_hw)
551 src_hw = dev->dev_addr;
552 if (!dest_hw)
553 dest_hw = dev->broadcast;
554
555 /*
556 * Fill the device header for the ARP frame
557 */
558 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
559 goto out;
560
561 /*
562 * Fill out the arp protocol part.
563 *
564 * The arp hardware type should match the device type, except for FDDI,
565 * which (according to RFC 1390) should always equal 1 (Ethernet).
566 */
567 /*
568 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
569 * DIX code for the protocol. Make these device structure fields.
570 */
571 switch (dev->type) {
572 default:
573 arp->ar_hrd = htons(dev->type);
574 arp->ar_pro = htons(ETH_P_IP);
575 break;
576
577#if IS_ENABLED(CONFIG_AX25)
578 case ARPHRD_AX25:
579 arp->ar_hrd = htons(ARPHRD_AX25);
580 arp->ar_pro = htons(AX25_P_IP);
581 break;
582
583#if IS_ENABLED(CONFIG_NETROM)
584 case ARPHRD_NETROM:
585 arp->ar_hrd = htons(ARPHRD_NETROM);
586 arp->ar_pro = htons(AX25_P_IP);
587 break;
588#endif
589#endif
590
591#if IS_ENABLED(CONFIG_FDDI)
592 case ARPHRD_FDDI:
593 arp->ar_hrd = htons(ARPHRD_ETHER);
594 arp->ar_pro = htons(ETH_P_IP);
595 break;
596#endif
597 }
598
599 arp->ar_hln = dev->addr_len;
600 arp->ar_pln = 4;
601 arp->ar_op = htons(type);
602
603 arp_ptr = (unsigned char *)(arp + 1);
604
605 memcpy(arp_ptr, src_hw, dev->addr_len);
606 arp_ptr += dev->addr_len;
607 memcpy(arp_ptr, &src_ip, 4);
608 arp_ptr += 4;
609
610 switch (dev->type) {
611#if IS_ENABLED(CONFIG_FIREWIRE_NET)
612 case ARPHRD_IEEE1394:
613 break;
614#endif
615 default:
616 if (target_hw)
617 memcpy(arp_ptr, target_hw, dev->addr_len);
618 else
619 memset(arp_ptr, 0, dev->addr_len);
620 arp_ptr += dev->addr_len;
621 }
622 memcpy(arp_ptr, &dest_ip, 4);
623
624 return skb;
625
626out:
627 kfree_skb(skb);
628 return NULL;
629}
630EXPORT_SYMBOL(arp_create);
631
632static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
633{
634 return dev_queue_xmit(skb);
635}
636
637/*
638 * Send an arp packet.
639 */
640void arp_xmit(struct sk_buff *skb)
641{
642 /* Send it off, maybe filter it using firewalling first. */
643 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
644 dev_net(skb->dev), NULL, skb, NULL, skb->dev,
645 arp_xmit_finish);
646}
647EXPORT_SYMBOL(arp_xmit);
648
649static bool arp_is_garp(struct net *net, struct net_device *dev,
650 int *addr_type, __be16 ar_op,
651 __be32 sip, __be32 tip,
652 unsigned char *sha, unsigned char *tha)
653{
654 bool is_garp = tip == sip;
655
656 /* Gratuitous ARP _replies_ also require target hwaddr to be
657 * the same as source.
658 */
659 if (is_garp && ar_op == htons(ARPOP_REPLY))
660 is_garp =
661 /* IPv4 over IEEE 1394 doesn't provide target
662 * hardware address field in its ARP payload.
663 */
664 tha &&
665 !memcmp(tha, sha, dev->addr_len);
666
667 if (is_garp) {
668 *addr_type = inet_addr_type_dev_table(net, dev, sip);
669 if (*addr_type != RTN_UNICAST)
670 is_garp = false;
671 }
672 return is_garp;
673}
674
675/*
676 * Process an arp request.
677 */
678
679static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
680{
681 struct net_device *dev = skb->dev;
682 struct in_device *in_dev = __in_dev_get_rcu(dev);
683 struct arphdr *arp;
684 unsigned char *arp_ptr;
685 struct rtable *rt;
686 unsigned char *sha;
687 unsigned char *tha = NULL;
688 __be32 sip, tip;
689 u16 dev_type = dev->type;
690 int addr_type;
691 struct neighbour *n;
692 struct dst_entry *reply_dst = NULL;
693 bool is_garp = false;
694
695 /* arp_rcv below verifies the ARP header and verifies the device
696 * is ARP'able.
697 */
698
699 if (!in_dev)
700 goto out_free_skb;
701
702 arp = arp_hdr(skb);
703
704 switch (dev_type) {
705 default:
706 if (arp->ar_pro != htons(ETH_P_IP) ||
707 htons(dev_type) != arp->ar_hrd)
708 goto out_free_skb;
709 break;
710 case ARPHRD_ETHER:
711 case ARPHRD_FDDI:
712 case ARPHRD_IEEE802:
713 /*
714 * ETHERNET, and Fibre Channel (which are IEEE 802
715 * devices, according to RFC 2625) devices will accept ARP
716 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
717 * This is the case also of FDDI, where the RFC 1390 says that
718 * FDDI devices should accept ARP hardware of (1) Ethernet,
719 * however, to be more robust, we'll accept both 1 (Ethernet)
720 * or 6 (IEEE 802.2)
721 */
722 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
723 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
724 arp->ar_pro != htons(ETH_P_IP))
725 goto out_free_skb;
726 break;
727 case ARPHRD_AX25:
728 if (arp->ar_pro != htons(AX25_P_IP) ||
729 arp->ar_hrd != htons(ARPHRD_AX25))
730 goto out_free_skb;
731 break;
732 case ARPHRD_NETROM:
733 if (arp->ar_pro != htons(AX25_P_IP) ||
734 arp->ar_hrd != htons(ARPHRD_NETROM))
735 goto out_free_skb;
736 break;
737 }
738
739 /* Understand only these message types */
740
741 if (arp->ar_op != htons(ARPOP_REPLY) &&
742 arp->ar_op != htons(ARPOP_REQUEST))
743 goto out_free_skb;
744
745/*
746 * Extract fields
747 */
748 arp_ptr = (unsigned char *)(arp + 1);
749 sha = arp_ptr;
750 arp_ptr += dev->addr_len;
751 memcpy(&sip, arp_ptr, 4);
752 arp_ptr += 4;
753 switch (dev_type) {
754#if IS_ENABLED(CONFIG_FIREWIRE_NET)
755 case ARPHRD_IEEE1394:
756 break;
757#endif
758 default:
759 tha = arp_ptr;
760 arp_ptr += dev->addr_len;
761 }
762 memcpy(&tip, arp_ptr, 4);
763/*
764 * Check for bad requests for 127.x.x.x and requests for multicast
765 * addresses. If this is one such, delete it.
766 */
767 if (ipv4_is_multicast(tip) ||
768 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
769 goto out_free_skb;
770
771 /*
772 * For some 802.11 wireless deployments (and possibly other networks),
773 * there will be an ARP proxy and gratuitous ARP frames are attacks
774 * and thus should not be accepted.
775 */
776 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
777 goto out_free_skb;
778
779/*
780 * Special case: We must set Frame Relay source Q.922 address
781 */
782 if (dev_type == ARPHRD_DLCI)
783 sha = dev->broadcast;
784
785/*
786 * Process entry. The idea here is we want to send a reply if it is a
787 * request for us or if it is a request for someone else that we hold
788 * a proxy for. We want to add an entry to our cache if it is a reply
789 * to us or if it is a request for our address.
790 * (The assumption for this last is that if someone is requesting our
791 * address, they are probably intending to talk to us, so it saves time
792 * if we cache their address. Their address is also probably not in
793 * our cache, since ours is not in their cache.)
794 *
795 * Putting this another way, we only care about replies if they are to
796 * us, in which case we add them to the cache. For requests, we care
797 * about those for us and those for our proxies. We reply to both,
798 * and in the case of requests for us we add the requester to the arp
799 * cache.
800 */
801
802 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
803 reply_dst = (struct dst_entry *)
804 iptunnel_metadata_reply(skb_metadata_dst(skb),
805 GFP_ATOMIC);
806
807 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
808 if (sip == 0) {
809 if (arp->ar_op == htons(ARPOP_REQUEST) &&
810 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
811 !arp_ignore(in_dev, sip, tip))
812 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
813 sha, dev->dev_addr, sha, reply_dst);
814 goto out_consume_skb;
815 }
816
817 if (arp->ar_op == htons(ARPOP_REQUEST) &&
818 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
819
820 rt = skb_rtable(skb);
821 addr_type = rt->rt_type;
822
823 if (addr_type == RTN_LOCAL) {
824 int dont_send;
825
826 dont_send = arp_ignore(in_dev, sip, tip);
827 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
828 dont_send = arp_filter(sip, tip, dev);
829 if (!dont_send) {
830 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
831 if (n) {
832 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
833 sip, dev, tip, sha,
834 dev->dev_addr, sha,
835 reply_dst);
836 neigh_release(n);
837 }
838 }
839 goto out_consume_skb;
840 } else if (IN_DEV_FORWARD(in_dev)) {
841 if (addr_type == RTN_UNICAST &&
842 (arp_fwd_proxy(in_dev, dev, rt) ||
843 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
844 (rt->dst.dev != dev &&
845 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
846 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
847 if (n)
848 neigh_release(n);
849
850 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
851 skb->pkt_type == PACKET_HOST ||
852 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
853 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
854 sip, dev, tip, sha,
855 dev->dev_addr, sha,
856 reply_dst);
857 } else {
858 pneigh_enqueue(&arp_tbl,
859 in_dev->arp_parms, skb);
860 goto out_free_dst;
861 }
862 goto out_consume_skb;
863 }
864 }
865 }
866
867 /* Update our ARP tables */
868
869 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
870
871 addr_type = -1;
872 if (n || IN_DEV_ARP_ACCEPT(in_dev)) {
873 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op,
874 sip, tip, sha, tha);
875 }
876
877 if (IN_DEV_ARP_ACCEPT(in_dev)) {
878 /* Unsolicited ARP is not accepted by default.
879 It is possible, that this option should be enabled for some
880 devices (strip is candidate)
881 */
882 if (!n &&
883 (is_garp ||
884 (arp->ar_op == htons(ARPOP_REPLY) &&
885 (addr_type == RTN_UNICAST ||
886 (addr_type < 0 &&
887 /* postpone calculation to as late as possible */
888 inet_addr_type_dev_table(net, dev, sip) ==
889 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,
903 n->updated +
904 NEIGH_VAR(n->parms, LOCKTIME)) ||
905 is_garp;
906
907 /* Broadcast replies and request packets
908 do not assert neighbour reachability.
909 */
910 if (arp->ar_op != htons(ARPOP_REPLY) ||
911 skb->pkt_type != PACKET_HOST)
912 state = NUD_STALE;
913 neigh_update(n, sha, state,
914 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0);
915 neigh_release(n);
916 }
917
918out_consume_skb:
919 consume_skb(skb);
920
921out_free_dst:
922 dst_release(reply_dst);
923 return NET_RX_SUCCESS;
924
925out_free_skb:
926 kfree_skb(skb);
927 return NET_RX_DROP;
928}
929
930static void parp_redo(struct sk_buff *skb)
931{
932 arp_process(dev_net(skb->dev), NULL, skb);
933}
934
935
936/*
937 * Receive an arp request from the device layer.
938 */
939
940static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
941 struct packet_type *pt, struct net_device *orig_dev)
942{
943 const struct arphdr *arp;
944
945 /* do not tweak dropwatch on an ARP we will ignore */
946 if (dev->flags & IFF_NOARP ||
947 skb->pkt_type == PACKET_OTHERHOST ||
948 skb->pkt_type == PACKET_LOOPBACK)
949 goto consumeskb;
950
951 skb = skb_share_check(skb, GFP_ATOMIC);
952 if (!skb)
953 goto out_of_mem;
954
955 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
956 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
957 goto freeskb;
958
959 arp = arp_hdr(skb);
960 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
961 goto freeskb;
962
963 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
964
965 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
966 dev_net(dev), NULL, skb, dev, NULL,
967 arp_process);
968
969consumeskb:
970 consume_skb(skb);
971 return NET_RX_SUCCESS;
972freeskb:
973 kfree_skb(skb);
974out_of_mem:
975 return NET_RX_DROP;
976}
977
978/*
979 * User level interface (ioctl)
980 */
981
982/*
983 * Set (create) an ARP cache entry.
984 */
985
986static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
987{
988 if (!dev) {
989 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
990 return 0;
991 }
992 if (__in_dev_get_rtnl(dev)) {
993 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
994 return 0;
995 }
996 return -ENXIO;
997}
998
999static int arp_req_set_public(struct net *net, struct arpreq *r,
1000 struct net_device *dev)
1001{
1002 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1003 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1004
1005 if (mask && mask != htonl(0xFFFFFFFF))
1006 return -EINVAL;
1007 if (!dev && (r->arp_flags & ATF_COM)) {
1008 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1009 r->arp_ha.sa_data);
1010 if (!dev)
1011 return -ENODEV;
1012 }
1013 if (mask) {
1014 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
1015 return -ENOBUFS;
1016 return 0;
1017 }
1018
1019 return arp_req_set_proxy(net, dev, 1);
1020}
1021
1022static int arp_req_set(struct net *net, struct arpreq *r,
1023 struct net_device *dev)
1024{
1025 __be32 ip;
1026 struct neighbour *neigh;
1027 int err;
1028
1029 if (r->arp_flags & ATF_PUBL)
1030 return arp_req_set_public(net, r, dev);
1031
1032 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1033 if (r->arp_flags & ATF_PERM)
1034 r->arp_flags |= ATF_COM;
1035 if (!dev) {
1036 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1037
1038 if (IS_ERR(rt))
1039 return PTR_ERR(rt);
1040 dev = rt->dst.dev;
1041 ip_rt_put(rt);
1042 if (!dev)
1043 return -EINVAL;
1044 }
1045 switch (dev->type) {
1046#if IS_ENABLED(CONFIG_FDDI)
1047 case ARPHRD_FDDI:
1048 /*
1049 * According to RFC 1390, FDDI devices should accept ARP
1050 * hardware types of 1 (Ethernet). However, to be more
1051 * robust, we'll accept hardware types of either 1 (Ethernet)
1052 * or 6 (IEEE 802.2).
1053 */
1054 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1055 r->arp_ha.sa_family != ARPHRD_ETHER &&
1056 r->arp_ha.sa_family != ARPHRD_IEEE802)
1057 return -EINVAL;
1058 break;
1059#endif
1060 default:
1061 if (r->arp_ha.sa_family != dev->type)
1062 return -EINVAL;
1063 break;
1064 }
1065
1066 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1067 err = PTR_ERR(neigh);
1068 if (!IS_ERR(neigh)) {
1069 unsigned int state = NUD_STALE;
1070 if (r->arp_flags & ATF_PERM)
1071 state = NUD_PERMANENT;
1072 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1073 r->arp_ha.sa_data : NULL, state,
1074 NEIGH_UPDATE_F_OVERRIDE |
1075 NEIGH_UPDATE_F_ADMIN, 0);
1076 neigh_release(neigh);
1077 }
1078 return err;
1079}
1080
1081static unsigned int arp_state_to_flags(struct neighbour *neigh)
1082{
1083 if (neigh->nud_state&NUD_PERMANENT)
1084 return ATF_PERM | ATF_COM;
1085 else if (neigh->nud_state&NUD_VALID)
1086 return ATF_COM;
1087 else
1088 return 0;
1089}
1090
1091/*
1092 * Get an ARP cache entry.
1093 */
1094
1095static int arp_req_get(struct arpreq *r, struct net_device *dev)
1096{
1097 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1098 struct neighbour *neigh;
1099 int err = -ENXIO;
1100
1101 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1102 if (neigh) {
1103 if (!(neigh->nud_state & NUD_NOARP)) {
1104 read_lock_bh(&neigh->lock);
1105 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1106 r->arp_flags = arp_state_to_flags(neigh);
1107 read_unlock_bh(&neigh->lock);
1108 r->arp_ha.sa_family = dev->type;
1109 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1110 err = 0;
1111 }
1112 neigh_release(neigh);
1113 }
1114 return err;
1115}
1116
1117static int arp_invalidate(struct net_device *dev, __be32 ip)
1118{
1119 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1120 int err = -ENXIO;
1121 struct neigh_table *tbl = &arp_tbl;
1122
1123 if (neigh) {
1124 if (neigh->nud_state & ~NUD_NOARP)
1125 err = neigh_update(neigh, NULL, NUD_FAILED,
1126 NEIGH_UPDATE_F_OVERRIDE|
1127 NEIGH_UPDATE_F_ADMIN, 0);
1128 write_lock_bh(&tbl->lock);
1129 neigh_release(neigh);
1130 neigh_remove_one(neigh, tbl);
1131 write_unlock_bh(&tbl->lock);
1132 }
1133
1134 return err;
1135}
1136
1137static int arp_req_delete_public(struct net *net, struct arpreq *r,
1138 struct net_device *dev)
1139{
1140 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1141 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1142
1143 if (mask == htonl(0xFFFFFFFF))
1144 return pneigh_delete(&arp_tbl, net, &ip, dev);
1145
1146 if (mask)
1147 return -EINVAL;
1148
1149 return arp_req_set_proxy(net, dev, 0);
1150}
1151
1152static int arp_req_delete(struct net *net, struct arpreq *r,
1153 struct net_device *dev)
1154{
1155 __be32 ip;
1156
1157 if (r->arp_flags & ATF_PUBL)
1158 return arp_req_delete_public(net, r, dev);
1159
1160 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1161 if (!dev) {
1162 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1163 if (IS_ERR(rt))
1164 return PTR_ERR(rt);
1165 dev = rt->dst.dev;
1166 ip_rt_put(rt);
1167 if (!dev)
1168 return -EINVAL;
1169 }
1170 return arp_invalidate(dev, ip);
1171}
1172
1173/*
1174 * Handle an ARP layer I/O control request.
1175 */
1176
1177int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1178{
1179 int err;
1180 struct arpreq r;
1181 struct net_device *dev = NULL;
1182
1183 switch (cmd) {
1184 case SIOCDARP:
1185 case SIOCSARP:
1186 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1187 return -EPERM;
1188 /* fall through */
1189 case SIOCGARP:
1190 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1191 if (err)
1192 return -EFAULT;
1193 break;
1194 default:
1195 return -EINVAL;
1196 }
1197
1198 if (r.arp_pa.sa_family != AF_INET)
1199 return -EPFNOSUPPORT;
1200
1201 if (!(r.arp_flags & ATF_PUBL) &&
1202 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1203 return -EINVAL;
1204 if (!(r.arp_flags & ATF_NETMASK))
1205 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1206 htonl(0xFFFFFFFFUL);
1207 rtnl_lock();
1208 if (r.arp_dev[0]) {
1209 err = -ENODEV;
1210 dev = __dev_get_by_name(net, r.arp_dev);
1211 if (!dev)
1212 goto out;
1213
1214 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1215 if (!r.arp_ha.sa_family)
1216 r.arp_ha.sa_family = dev->type;
1217 err = -EINVAL;
1218 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1219 goto out;
1220 } else if (cmd == SIOCGARP) {
1221 err = -ENODEV;
1222 goto out;
1223 }
1224
1225 switch (cmd) {
1226 case SIOCDARP:
1227 err = arp_req_delete(net, &r, dev);
1228 break;
1229 case SIOCSARP:
1230 err = arp_req_set(net, &r, dev);
1231 break;
1232 case SIOCGARP:
1233 err = arp_req_get(&r, dev);
1234 break;
1235 }
1236out:
1237 rtnl_unlock();
1238 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1239 err = -EFAULT;
1240 return err;
1241}
1242
1243static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1244 void *ptr)
1245{
1246 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1247 struct netdev_notifier_change_info *change_info;
1248
1249 switch (event) {
1250 case NETDEV_CHANGEADDR:
1251 neigh_changeaddr(&arp_tbl, dev);
1252 rt_cache_flush(dev_net(dev));
1253 break;
1254 case NETDEV_CHANGE:
1255 change_info = ptr;
1256 if (change_info->flags_changed & IFF_NOARP)
1257 neigh_changeaddr(&arp_tbl, dev);
1258 break;
1259 default:
1260 break;
1261 }
1262
1263 return NOTIFY_DONE;
1264}
1265
1266static struct notifier_block arp_netdev_notifier = {
1267 .notifier_call = arp_netdev_event,
1268};
1269
1270/* Note, that it is not on notifier chain.
1271 It is necessary, that this routine was called after route cache will be
1272 flushed.
1273 */
1274void arp_ifdown(struct net_device *dev)
1275{
1276 neigh_ifdown(&arp_tbl, dev);
1277}
1278
1279
1280/*
1281 * Called once on startup.
1282 */
1283
1284static struct packet_type arp_packet_type __read_mostly = {
1285 .type = cpu_to_be16(ETH_P_ARP),
1286 .func = arp_rcv,
1287};
1288
1289static int arp_proc_init(void);
1290
1291void __init arp_init(void)
1292{
1293 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
1294
1295 dev_add_pack(&arp_packet_type);
1296 arp_proc_init();
1297#ifdef CONFIG_SYSCTL
1298 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1299#endif
1300 register_netdevice_notifier(&arp_netdev_notifier);
1301}
1302
1303#ifdef CONFIG_PROC_FS
1304#if IS_ENABLED(CONFIG_AX25)
1305
1306/* ------------------------------------------------------------------------ */
1307/*
1308 * ax25 -> ASCII conversion
1309 */
1310static void ax2asc2(ax25_address *a, char *buf)
1311{
1312 char c, *s;
1313 int n;
1314
1315 for (n = 0, s = buf; n < 6; n++) {
1316 c = (a->ax25_call[n] >> 1) & 0x7F;
1317
1318 if (c != ' ')
1319 *s++ = c;
1320 }
1321
1322 *s++ = '-';
1323 n = (a->ax25_call[6] >> 1) & 0x0F;
1324 if (n > 9) {
1325 *s++ = '1';
1326 n -= 10;
1327 }
1328
1329 *s++ = n + '0';
1330 *s++ = '\0';
1331
1332 if (*buf == '\0' || *buf == '-') {
1333 buf[0] = '*';
1334 buf[1] = '\0';
1335 }
1336}
1337#endif /* CONFIG_AX25 */
1338
1339#define HBUFFERLEN 30
1340
1341static void arp_format_neigh_entry(struct seq_file *seq,
1342 struct neighbour *n)
1343{
1344 char hbuffer[HBUFFERLEN];
1345 int k, j;
1346 char tbuf[16];
1347 struct net_device *dev = n->dev;
1348 int hatype = dev->type;
1349
1350 read_lock(&n->lock);
1351 /* Convert hardware address to XX:XX:XX:XX ... form. */
1352#if IS_ENABLED(CONFIG_AX25)
1353 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1354 ax2asc2((ax25_address *)n->ha, hbuffer);
1355 else {
1356#endif
1357 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1358 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1359 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1360 hbuffer[k++] = ':';
1361 }
1362 if (k != 0)
1363 --k;
1364 hbuffer[k] = 0;
1365#if IS_ENABLED(CONFIG_AX25)
1366 }
1367#endif
1368 sprintf(tbuf, "%pI4", n->primary_key);
1369 seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n",
1370 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1371 read_unlock(&n->lock);
1372}
1373
1374static void arp_format_pneigh_entry(struct seq_file *seq,
1375 struct pneigh_entry *n)
1376{
1377 struct net_device *dev = n->dev;
1378 int hatype = dev ? dev->type : 0;
1379 char tbuf[16];
1380
1381 sprintf(tbuf, "%pI4", n->key);
1382 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1383 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1384 dev ? dev->name : "*");
1385}
1386
1387static int arp_seq_show(struct seq_file *seq, void *v)
1388{
1389 if (v == SEQ_START_TOKEN) {
1390 seq_puts(seq, "IP address HW type Flags "
1391 "HW address Mask Device\n");
1392 } else {
1393 struct neigh_seq_state *state = seq->private;
1394
1395 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1396 arp_format_pneigh_entry(seq, v);
1397 else
1398 arp_format_neigh_entry(seq, v);
1399 }
1400
1401 return 0;
1402}
1403
1404static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1405{
1406 /* Don't want to confuse "arp -a" w/ magic entries,
1407 * so we tell the generic iterator to skip NUD_NOARP.
1408 */
1409 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1410}
1411
1412/* ------------------------------------------------------------------------ */
1413
1414static const struct seq_operations arp_seq_ops = {
1415 .start = arp_seq_start,
1416 .next = neigh_seq_next,
1417 .stop = neigh_seq_stop,
1418 .show = arp_seq_show,
1419};
1420
1421static int arp_seq_open(struct inode *inode, struct file *file)
1422{
1423 return seq_open_net(inode, file, &arp_seq_ops,
1424 sizeof(struct neigh_seq_state));
1425}
1426
1427static const struct file_operations arp_seq_fops = {
1428 .open = arp_seq_open,
1429 .read = seq_read,
1430 .llseek = seq_lseek,
1431 .release = seq_release_net,
1432};
1433
1434
1435static int __net_init arp_net_init(struct net *net)
1436{
1437 if (!proc_create("arp", 0444, net->proc_net, &arp_seq_fops))
1438 return -ENOMEM;
1439 return 0;
1440}
1441
1442static void __net_exit arp_net_exit(struct net *net)
1443{
1444 remove_proc_entry("arp", net->proc_net);
1445}
1446
1447static struct pernet_operations arp_net_ops = {
1448 .init = arp_net_init,
1449 .exit = arp_net_exit,
1450};
1451
1452static int __init arp_proc_init(void)
1453{
1454 return register_pernet_subsys(&arp_net_ops);
1455}
1456
1457#else /* CONFIG_PROC_FS */
1458
1459static int __init arp_proc_init(void)
1460{
1461 return 0;
1462}
1463
1464#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 */