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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* linux/net/ipv4/arp.c
3 *
4 * Copyright (C) 1994 by Florian La Roche
5 *
6 * This module implements the Address Resolution Protocol ARP (RFC 826),
7 * which is used to convert IP addresses (or in the future maybe other
8 * high-level addresses) into a low-level hardware address (like an Ethernet
9 * address).
10 *
11 * Fixes:
12 * Alan Cox : Removed the Ethernet assumptions in
13 * Florian's code
14 * Alan Cox : Fixed some small errors in the ARP
15 * logic
16 * Alan Cox : Allow >4K in /proc
17 * Alan Cox : Make ARP add its own protocol entry
18 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
19 * Stephen Henson : Add AX25 support to arp_get_info()
20 * Alan Cox : Drop data when a device is downed.
21 * Alan Cox : Use init_timer().
22 * Alan Cox : Double lock fixes.
23 * Martin Seine : Move the arphdr structure
24 * to if_arp.h for compatibility.
25 * with BSD based programs.
26 * Andrew Tridgell : Added ARP netmask code and
27 * re-arranged proxy handling.
28 * Alan Cox : Changed to use notifiers.
29 * Niibe Yutaka : Reply for this device or proxies only.
30 * Alan Cox : Don't proxy across hardware types!
31 * Jonathan Naylor : Added support for NET/ROM.
32 * Mike Shaver : RFC1122 checks.
33 * Jonathan Naylor : Only lookup the hardware address for
34 * the correct hardware type.
35 * Germano Caronni : Assorted subtle races.
36 * Craig Schlenter : Don't modify permanent entry
37 * during arp_rcv.
38 * Russ Nelson : Tidied up a few bits.
39 * Alexey Kuznetsov: Major changes to caching and behaviour,
40 * eg intelligent arp probing and
41 * generation
42 * of host down events.
43 * Alan Cox : Missing unlock in device events.
44 * Eckes : ARP ioctl control errors.
45 * Alexey Kuznetsov: Arp free fix.
46 * Manuel Rodriguez: Gratuitous ARP.
47 * Jonathan Layes : Added arpd support through kerneld
48 * message queue (960314)
49 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
50 * Mike McLagan : Routing by source
51 * Stuart Cheshire : Metricom and grat arp fixes
52 * *** FOR 2.1 clean this up ***
53 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
54 * Alan Cox : Took the AP1000 nasty FDDI hack and
55 * folded into the mainstream FDDI code.
56 * Ack spit, Linus how did you allow that
57 * one in...
58 * Jes Sorensen : Make FDDI work again in 2.1.x and
59 * clean up the APFDDI & gen. FDDI bits.
60 * Alexey Kuznetsov: new arp state machine;
61 * now it is in net/core/neighbour.c.
62 * Krzysztof Halasa: Added Frame Relay ARP support.
63 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
64 * Shmulik Hen: Split arp_send to arp_create and
65 * arp_xmit so intermediate drivers like
66 * bonding can change the skb before
67 * sending (e.g. insert 8021q tag).
68 * Harald Welte : convert to make use of jenkins hash
69 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
70 */
71
72#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
73
74#include <linux/module.h>
75#include <linux/types.h>
76#include <linux/string.h>
77#include <linux/kernel.h>
78#include <linux/capability.h>
79#include <linux/socket.h>
80#include <linux/sockios.h>
81#include <linux/errno.h>
82#include <linux/in.h>
83#include <linux/mm.h>
84#include <linux/inet.h>
85#include <linux/inetdevice.h>
86#include <linux/netdevice.h>
87#include <linux/etherdevice.h>
88#include <linux/fddidevice.h>
89#include <linux/if_arp.h>
90#include <linux/skbuff.h>
91#include <linux/proc_fs.h>
92#include <linux/seq_file.h>
93#include <linux/stat.h>
94#include <linux/init.h>
95#include <linux/net.h>
96#include <linux/rcupdate.h>
97#include <linux/slab.h>
98#ifdef CONFIG_SYSCTL
99#include <linux/sysctl.h>
100#endif
101
102#include <net/net_namespace.h>
103#include <net/ip.h>
104#include <net/icmp.h>
105#include <net/route.h>
106#include <net/protocol.h>
107#include <net/tcp.h>
108#include <net/sock.h>
109#include <net/arp.h>
110#include <net/ax25.h>
111#include <net/netrom.h>
112#include <net/dst_metadata.h>
113#include <net/ip_tunnels.h>
114
115#include <linux/uaccess.h>
116
117#include <linux/netfilter_arp.h>
118
119/*
120 * Interface to generic neighbour cache.
121 */
122static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
123static bool arp_key_eq(const struct neighbour *n, const void *pkey);
124static int arp_constructor(struct neighbour *neigh);
125static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
126static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
127static void parp_redo(struct sk_buff *skb);
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_MAX,
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 arp = 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 /*
576 * Fill the device header for the ARP frame
577 */
578 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
579 goto out;
580
581 /*
582 * Fill out the arp protocol part.
583 *
584 * The arp hardware type should match the device type, except for FDDI,
585 * which (according to RFC 1390) should always equal 1 (Ethernet).
586 */
587 /*
588 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
589 * DIX code for the protocol. Make these device structure fields.
590 */
591 switch (dev->type) {
592 default:
593 arp->ar_hrd = htons(dev->type);
594 arp->ar_pro = htons(ETH_P_IP);
595 break;
596
597#if IS_ENABLED(CONFIG_AX25)
598 case ARPHRD_AX25:
599 arp->ar_hrd = htons(ARPHRD_AX25);
600 arp->ar_pro = htons(AX25_P_IP);
601 break;
602
603#if IS_ENABLED(CONFIG_NETROM)
604 case ARPHRD_NETROM:
605 arp->ar_hrd = htons(ARPHRD_NETROM);
606 arp->ar_pro = htons(AX25_P_IP);
607 break;
608#endif
609#endif
610
611#if IS_ENABLED(CONFIG_FDDI)
612 case ARPHRD_FDDI:
613 arp->ar_hrd = htons(ARPHRD_ETHER);
614 arp->ar_pro = htons(ETH_P_IP);
615 break;
616#endif
617 }
618
619 arp->ar_hln = dev->addr_len;
620 arp->ar_pln = 4;
621 arp->ar_op = htons(type);
622
623 arp_ptr = (unsigned char *)(arp + 1);
624
625 memcpy(arp_ptr, src_hw, dev->addr_len);
626 arp_ptr += dev->addr_len;
627 memcpy(arp_ptr, &src_ip, 4);
628 arp_ptr += 4;
629
630 switch (dev->type) {
631#if IS_ENABLED(CONFIG_FIREWIRE_NET)
632 case ARPHRD_IEEE1394:
633 break;
634#endif
635 default:
636 if (target_hw)
637 memcpy(arp_ptr, target_hw, dev->addr_len);
638 else
639 memset(arp_ptr, 0, dev->addr_len);
640 arp_ptr += dev->addr_len;
641 }
642 memcpy(arp_ptr, &dest_ip, 4);
643
644 return skb;
645
646out:
647 kfree_skb(skb);
648 return NULL;
649}
650EXPORT_SYMBOL(arp_create);
651
652static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
653{
654 return dev_queue_xmit(skb);
655}
656
657/*
658 * Send an arp packet.
659 */
660void arp_xmit(struct sk_buff *skb)
661{
662 rcu_read_lock();
663 /* Send it off, maybe filter it using firewalling first. */
664 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
665 dev_net_rcu(skb->dev), NULL, skb, NULL, skb->dev,
666 arp_xmit_finish);
667 rcu_read_unlock();
668}
669EXPORT_SYMBOL(arp_xmit);
670
671static bool arp_is_garp(struct net *net, struct net_device *dev,
672 int *addr_type, __be16 ar_op,
673 __be32 sip, __be32 tip,
674 unsigned char *sha, unsigned char *tha)
675{
676 bool is_garp = tip == sip;
677
678 /* Gratuitous ARP _replies_ also require target hwaddr to be
679 * the same as source.
680 */
681 if (is_garp && ar_op == htons(ARPOP_REPLY))
682 is_garp =
683 /* IPv4 over IEEE 1394 doesn't provide target
684 * hardware address field in its ARP payload.
685 */
686 tha &&
687 !memcmp(tha, sha, dev->addr_len);
688
689 if (is_garp) {
690 *addr_type = inet_addr_type_dev_table(net, dev, sip);
691 if (*addr_type != RTN_UNICAST)
692 is_garp = false;
693 }
694 return is_garp;
695}
696
697/*
698 * Process an arp request.
699 */
700
701static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
702{
703 struct net_device *dev = skb->dev;
704 struct in_device *in_dev = __in_dev_get_rcu(dev);
705 struct arphdr *arp;
706 unsigned char *arp_ptr;
707 struct rtable *rt;
708 unsigned char *sha;
709 unsigned char *tha = NULL;
710 __be32 sip, tip;
711 u16 dev_type = dev->type;
712 int addr_type;
713 struct neighbour *n;
714 struct dst_entry *reply_dst = NULL;
715 bool is_garp = false;
716
717 /* arp_rcv below verifies the ARP header and verifies the device
718 * is ARP'able.
719 */
720
721 if (!in_dev)
722 goto out_free_skb;
723
724 arp = arp_hdr(skb);
725
726 switch (dev_type) {
727 default:
728 if (arp->ar_pro != htons(ETH_P_IP) ||
729 htons(dev_type) != arp->ar_hrd)
730 goto out_free_skb;
731 break;
732 case ARPHRD_ETHER:
733 case ARPHRD_FDDI:
734 case ARPHRD_IEEE802:
735 /*
736 * ETHERNET, and Fibre Channel (which are IEEE 802
737 * devices, according to RFC 2625) devices will accept ARP
738 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
739 * This is the case also of FDDI, where the RFC 1390 says that
740 * FDDI devices should accept ARP hardware of (1) Ethernet,
741 * however, to be more robust, we'll accept both 1 (Ethernet)
742 * or 6 (IEEE 802.2)
743 */
744 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
745 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
746 arp->ar_pro != htons(ETH_P_IP))
747 goto out_free_skb;
748 break;
749 case ARPHRD_AX25:
750 if (arp->ar_pro != htons(AX25_P_IP) ||
751 arp->ar_hrd != htons(ARPHRD_AX25))
752 goto out_free_skb;
753 break;
754 case ARPHRD_NETROM:
755 if (arp->ar_pro != htons(AX25_P_IP) ||
756 arp->ar_hrd != htons(ARPHRD_NETROM))
757 goto out_free_skb;
758 break;
759 }
760
761 /* Understand only these message types */
762
763 if (arp->ar_op != htons(ARPOP_REPLY) &&
764 arp->ar_op != htons(ARPOP_REQUEST))
765 goto out_free_skb;
766
767/*
768 * Extract fields
769 */
770 arp_ptr = (unsigned char *)(arp + 1);
771 sha = arp_ptr;
772 arp_ptr += dev->addr_len;
773 memcpy(&sip, arp_ptr, 4);
774 arp_ptr += 4;
775 switch (dev_type) {
776#if IS_ENABLED(CONFIG_FIREWIRE_NET)
777 case ARPHRD_IEEE1394:
778 break;
779#endif
780 default:
781 tha = arp_ptr;
782 arp_ptr += dev->addr_len;
783 }
784 memcpy(&tip, arp_ptr, 4);
785/*
786 * Check for bad requests for 127.x.x.x and requests for multicast
787 * addresses. If this is one such, delete it.
788 */
789 if (ipv4_is_multicast(tip) ||
790 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
791 goto out_free_skb;
792
793 /*
794 * For some 802.11 wireless deployments (and possibly other networks),
795 * there will be an ARP proxy and gratuitous ARP frames are attacks
796 * and thus should not be accepted.
797 */
798 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
799 goto out_free_skb;
800
801/*
802 * Special case: We must set Frame Relay source Q.922 address
803 */
804 if (dev_type == ARPHRD_DLCI)
805 sha = dev->broadcast;
806
807/*
808 * Process entry. The idea here is we want to send a reply if it is a
809 * request for us or if it is a request for someone else that we hold
810 * a proxy for. We want to add an entry to our cache if it is a reply
811 * to us or if it is a request for our address.
812 * (The assumption for this last is that if someone is requesting our
813 * address, they are probably intending to talk to us, so it saves time
814 * if we cache their address. Their address is also probably not in
815 * our cache, since ours is not in their cache.)
816 *
817 * Putting this another way, we only care about replies if they are to
818 * us, in which case we add them to the cache. For requests, we care
819 * about those for us and those for our proxies. We reply to both,
820 * and in the case of requests for us we add the requester to the arp
821 * cache.
822 */
823
824 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
825 reply_dst = (struct dst_entry *)
826 iptunnel_metadata_reply(skb_metadata_dst(skb),
827 GFP_ATOMIC);
828
829 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
830 if (sip == 0) {
831 if (arp->ar_op == htons(ARPOP_REQUEST) &&
832 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
833 !arp_ignore(in_dev, sip, tip))
834 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
835 sha, dev->dev_addr, sha, reply_dst);
836 goto out_consume_skb;
837 }
838
839 if (arp->ar_op == htons(ARPOP_REQUEST) &&
840 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
841
842 rt = skb_rtable(skb);
843 addr_type = rt->rt_type;
844
845 if (addr_type == RTN_LOCAL) {
846 int dont_send;
847
848 dont_send = arp_ignore(in_dev, sip, tip);
849 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
850 dont_send = arp_filter(sip, tip, dev);
851 if (!dont_send) {
852 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
853 if (n) {
854 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
855 sip, dev, tip, sha,
856 dev->dev_addr, sha,
857 reply_dst);
858 neigh_release(n);
859 }
860 }
861 goto out_consume_skb;
862 } else if (IN_DEV_FORWARD(in_dev)) {
863 if (addr_type == RTN_UNICAST &&
864 (arp_fwd_proxy(in_dev, dev, rt) ||
865 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
866 (rt->dst.dev != dev &&
867 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
868 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
869 if (n)
870 neigh_release(n);
871
872 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
873 skb->pkt_type == PACKET_HOST ||
874 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
875 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
876 sip, dev, tip, sha,
877 dev->dev_addr, sha,
878 reply_dst);
879 } else {
880 pneigh_enqueue(&arp_tbl,
881 in_dev->arp_parms, skb);
882 goto out_free_dst;
883 }
884 goto out_consume_skb;
885 }
886 }
887 }
888
889 /* Update our ARP tables */
890
891 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
892
893 addr_type = -1;
894 if (n || arp_accept(in_dev, sip)) {
895 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op,
896 sip, tip, sha, tha);
897 }
898
899 if (arp_accept(in_dev, sip)) {
900 /* Unsolicited ARP is not accepted by default.
901 It is possible, that this option should be enabled for some
902 devices (strip is candidate)
903 */
904 if (!n &&
905 (is_garp ||
906 (arp->ar_op == htons(ARPOP_REPLY) &&
907 (addr_type == RTN_UNICAST ||
908 (addr_type < 0 &&
909 /* postpone calculation to as late as possible */
910 inet_addr_type_dev_table(net, dev, sip) ==
911 RTN_UNICAST)))))
912 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
913 }
914
915 if (n) {
916 int state = NUD_REACHABLE;
917 int override;
918
919 /* If several different ARP replies follows back-to-back,
920 use the FIRST one. It is possible, if several proxy
921 agents are active. Taking the first reply prevents
922 arp trashing and chooses the fastest router.
923 */
924 override = time_after(jiffies,
925 n->updated +
926 NEIGH_VAR(n->parms, LOCKTIME)) ||
927 is_garp;
928
929 /* Broadcast replies and request packets
930 do not assert neighbour reachability.
931 */
932 if (arp->ar_op != htons(ARPOP_REPLY) ||
933 skb->pkt_type != PACKET_HOST)
934 state = NUD_STALE;
935 neigh_update(n, sha, state,
936 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0);
937 neigh_release(n);
938 }
939
940out_consume_skb:
941 consume_skb(skb);
942
943out_free_dst:
944 dst_release(reply_dst);
945 return NET_RX_SUCCESS;
946
947out_free_skb:
948 kfree_skb(skb);
949 return NET_RX_DROP;
950}
951
952static void parp_redo(struct sk_buff *skb)
953{
954 arp_process(dev_net(skb->dev), NULL, skb);
955}
956
957static int arp_is_multicast(const void *pkey)
958{
959 return ipv4_is_multicast(*((__be32 *)pkey));
960}
961
962/*
963 * Receive an arp request from the device layer.
964 */
965
966static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
967 struct packet_type *pt, struct net_device *orig_dev)
968{
969 const struct arphdr *arp;
970
971 /* do not tweak dropwatch on an ARP we will ignore */
972 if (dev->flags & IFF_NOARP ||
973 skb->pkt_type == PACKET_OTHERHOST ||
974 skb->pkt_type == PACKET_LOOPBACK)
975 goto consumeskb;
976
977 skb = skb_share_check(skb, GFP_ATOMIC);
978 if (!skb)
979 goto out_of_mem;
980
981 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
982 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
983 goto freeskb;
984
985 arp = arp_hdr(skb);
986 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
987 goto freeskb;
988
989 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
990
991 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
992 dev_net(dev), NULL, skb, dev, NULL,
993 arp_process);
994
995consumeskb:
996 consume_skb(skb);
997 return NET_RX_SUCCESS;
998freeskb:
999 kfree_skb(skb);
1000out_of_mem:
1001 return NET_RX_DROP;
1002}
1003
1004/*
1005 * User level interface (ioctl)
1006 */
1007
1008static struct net_device *arp_req_dev_by_name(struct net *net, struct arpreq *r,
1009 bool getarp)
1010{
1011 struct net_device *dev;
1012
1013 if (getarp)
1014 dev = dev_get_by_name_rcu(net, r->arp_dev);
1015 else
1016 dev = __dev_get_by_name(net, r->arp_dev);
1017 if (!dev)
1018 return ERR_PTR(-ENODEV);
1019
1020 /* Mmmm... It is wrong... ARPHRD_NETROM == 0 */
1021 if (!r->arp_ha.sa_family)
1022 r->arp_ha.sa_family = dev->type;
1023
1024 if ((r->arp_flags & ATF_COM) && r->arp_ha.sa_family != dev->type)
1025 return ERR_PTR(-EINVAL);
1026
1027 return dev;
1028}
1029
1030static struct net_device *arp_req_dev(struct net *net, struct arpreq *r)
1031{
1032 struct net_device *dev;
1033 struct rtable *rt;
1034 __be32 ip;
1035
1036 if (r->arp_dev[0])
1037 return arp_req_dev_by_name(net, r, false);
1038
1039 if (r->arp_flags & ATF_PUBL)
1040 return NULL;
1041
1042 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1043
1044 rt = ip_route_output(net, ip, 0, 0, 0, RT_SCOPE_LINK);
1045 if (IS_ERR(rt))
1046 return ERR_CAST(rt);
1047
1048 dev = rt->dst.dev;
1049 ip_rt_put(rt);
1050
1051 if (!dev)
1052 return ERR_PTR(-EINVAL);
1053
1054 return dev;
1055}
1056
1057/*
1058 * Set (create) an ARP cache entry.
1059 */
1060
1061static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
1062{
1063 if (!dev) {
1064 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
1065 return 0;
1066 }
1067 if (__in_dev_get_rtnl(dev)) {
1068 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
1069 return 0;
1070 }
1071 return -ENXIO;
1072}
1073
1074static int arp_req_set_public(struct net *net, struct arpreq *r,
1075 struct net_device *dev)
1076{
1077 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1078
1079 if (!dev && (r->arp_flags & ATF_COM)) {
1080 dev = dev_getbyhwaddr(net, r->arp_ha.sa_family,
1081 r->arp_ha.sa_data);
1082 if (!dev)
1083 return -ENODEV;
1084 }
1085 if (mask) {
1086 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1087
1088 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
1089 return -ENOBUFS;
1090 return 0;
1091 }
1092
1093 return arp_req_set_proxy(net, dev, 1);
1094}
1095
1096static int arp_req_set(struct net *net, struct arpreq *r)
1097{
1098 struct neighbour *neigh;
1099 struct net_device *dev;
1100 __be32 ip;
1101 int err;
1102
1103 dev = arp_req_dev(net, r);
1104 if (IS_ERR(dev))
1105 return PTR_ERR(dev);
1106
1107 if (r->arp_flags & ATF_PUBL)
1108 return arp_req_set_public(net, r, dev);
1109
1110 switch (dev->type) {
1111#if IS_ENABLED(CONFIG_FDDI)
1112 case ARPHRD_FDDI:
1113 /*
1114 * According to RFC 1390, FDDI devices should accept ARP
1115 * hardware types of 1 (Ethernet). However, to be more
1116 * robust, we'll accept hardware types of either 1 (Ethernet)
1117 * or 6 (IEEE 802.2).
1118 */
1119 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1120 r->arp_ha.sa_family != ARPHRD_ETHER &&
1121 r->arp_ha.sa_family != ARPHRD_IEEE802)
1122 return -EINVAL;
1123 break;
1124#endif
1125 default:
1126 if (r->arp_ha.sa_family != dev->type)
1127 return -EINVAL;
1128 break;
1129 }
1130
1131 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1132
1133 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1134 err = PTR_ERR(neigh);
1135 if (!IS_ERR(neigh)) {
1136 unsigned int state = NUD_STALE;
1137
1138 if (r->arp_flags & ATF_PERM) {
1139 r->arp_flags |= ATF_COM;
1140 state = NUD_PERMANENT;
1141 }
1142
1143 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1144 r->arp_ha.sa_data : NULL, state,
1145 NEIGH_UPDATE_F_OVERRIDE |
1146 NEIGH_UPDATE_F_ADMIN, 0);
1147 neigh_release(neigh);
1148 }
1149 return err;
1150}
1151
1152static unsigned int arp_state_to_flags(struct neighbour *neigh)
1153{
1154 if (neigh->nud_state&NUD_PERMANENT)
1155 return ATF_PERM | ATF_COM;
1156 else if (neigh->nud_state&NUD_VALID)
1157 return ATF_COM;
1158 else
1159 return 0;
1160}
1161
1162/*
1163 * Get an ARP cache entry.
1164 */
1165
1166static int arp_req_get(struct net *net, struct arpreq *r)
1167{
1168 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1169 struct neighbour *neigh;
1170 struct net_device *dev;
1171
1172 if (!r->arp_dev[0])
1173 return -ENODEV;
1174
1175 dev = arp_req_dev_by_name(net, r, true);
1176 if (IS_ERR(dev))
1177 return PTR_ERR(dev);
1178
1179 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1180 if (!neigh)
1181 return -ENXIO;
1182
1183 if (READ_ONCE(neigh->nud_state) & NUD_NOARP) {
1184 neigh_release(neigh);
1185 return -ENXIO;
1186 }
1187
1188 read_lock_bh(&neigh->lock);
1189 memcpy(r->arp_ha.sa_data, neigh->ha,
1190 min(dev->addr_len, sizeof(r->arp_ha.sa_data_min)));
1191 r->arp_flags = arp_state_to_flags(neigh);
1192 read_unlock_bh(&neigh->lock);
1193
1194 neigh_release(neigh);
1195
1196 r->arp_ha.sa_family = dev->type;
1197 netdev_copy_name(dev, r->arp_dev);
1198
1199 return 0;
1200}
1201
1202int arp_invalidate(struct net_device *dev, __be32 ip, bool force)
1203{
1204 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1205 int err = -ENXIO;
1206 struct neigh_table *tbl = &arp_tbl;
1207
1208 if (neigh) {
1209 if ((READ_ONCE(neigh->nud_state) & NUD_VALID) && !force) {
1210 neigh_release(neigh);
1211 return 0;
1212 }
1213
1214 if (READ_ONCE(neigh->nud_state) & ~NUD_NOARP)
1215 err = neigh_update(neigh, NULL, NUD_FAILED,
1216 NEIGH_UPDATE_F_OVERRIDE|
1217 NEIGH_UPDATE_F_ADMIN, 0);
1218 write_lock_bh(&tbl->lock);
1219 neigh_release(neigh);
1220 neigh_remove_one(neigh);
1221 write_unlock_bh(&tbl->lock);
1222 }
1223
1224 return err;
1225}
1226
1227static int arp_req_delete_public(struct net *net, struct arpreq *r,
1228 struct net_device *dev)
1229{
1230 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1231
1232 if (mask) {
1233 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1234
1235 return pneigh_delete(&arp_tbl, net, &ip, dev);
1236 }
1237
1238 return arp_req_set_proxy(net, dev, 0);
1239}
1240
1241static int arp_req_delete(struct net *net, struct arpreq *r)
1242{
1243 struct net_device *dev;
1244 __be32 ip;
1245
1246 dev = arp_req_dev(net, r);
1247 if (IS_ERR(dev))
1248 return PTR_ERR(dev);
1249
1250 if (r->arp_flags & ATF_PUBL)
1251 return arp_req_delete_public(net, r, dev);
1252
1253 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1254
1255 return arp_invalidate(dev, ip, true);
1256}
1257
1258/*
1259 * Handle an ARP layer I/O control request.
1260 */
1261
1262int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1263{
1264 struct arpreq r;
1265 __be32 *netmask;
1266 int err;
1267
1268 switch (cmd) {
1269 case SIOCDARP:
1270 case SIOCSARP:
1271 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1272 return -EPERM;
1273 fallthrough;
1274 case SIOCGARP:
1275 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1276 if (err)
1277 return -EFAULT;
1278 break;
1279 default:
1280 return -EINVAL;
1281 }
1282
1283 if (r.arp_pa.sa_family != AF_INET)
1284 return -EPFNOSUPPORT;
1285
1286 if (!(r.arp_flags & ATF_PUBL) &&
1287 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1288 return -EINVAL;
1289
1290 netmask = &((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr;
1291 if (!(r.arp_flags & ATF_NETMASK))
1292 *netmask = htonl(0xFFFFFFFFUL);
1293 else if (*netmask && *netmask != htonl(0xFFFFFFFFUL))
1294 return -EINVAL;
1295
1296 switch (cmd) {
1297 case SIOCDARP:
1298 rtnl_lock();
1299 err = arp_req_delete(net, &r);
1300 rtnl_unlock();
1301 break;
1302 case SIOCSARP:
1303 rtnl_lock();
1304 err = arp_req_set(net, &r);
1305 rtnl_unlock();
1306 break;
1307 case SIOCGARP:
1308 rcu_read_lock();
1309 err = arp_req_get(net, &r);
1310 rcu_read_unlock();
1311
1312 if (!err && copy_to_user(arg, &r, sizeof(r)))
1313 err = -EFAULT;
1314 break;
1315 }
1316
1317 return err;
1318}
1319
1320static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1321 void *ptr)
1322{
1323 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1324 struct netdev_notifier_change_info *change_info;
1325 struct in_device *in_dev;
1326 bool evict_nocarrier;
1327
1328 switch (event) {
1329 case NETDEV_CHANGEADDR:
1330 neigh_changeaddr(&arp_tbl, dev);
1331 rt_cache_flush(dev_net(dev));
1332 break;
1333 case NETDEV_CHANGE:
1334 change_info = ptr;
1335 if (change_info->flags_changed & IFF_NOARP)
1336 neigh_changeaddr(&arp_tbl, dev);
1337
1338 in_dev = __in_dev_get_rtnl(dev);
1339 if (!in_dev)
1340 evict_nocarrier = true;
1341 else
1342 evict_nocarrier = IN_DEV_ARP_EVICT_NOCARRIER(in_dev);
1343
1344 if (evict_nocarrier && !netif_carrier_ok(dev))
1345 neigh_carrier_down(&arp_tbl, dev);
1346 break;
1347 default:
1348 break;
1349 }
1350
1351 return NOTIFY_DONE;
1352}
1353
1354static struct notifier_block arp_netdev_notifier = {
1355 .notifier_call = arp_netdev_event,
1356};
1357
1358/* Note, that it is not on notifier chain.
1359 It is necessary, that this routine was called after route cache will be
1360 flushed.
1361 */
1362void arp_ifdown(struct net_device *dev)
1363{
1364 neigh_ifdown(&arp_tbl, dev);
1365}
1366
1367
1368/*
1369 * Called once on startup.
1370 */
1371
1372static struct packet_type arp_packet_type __read_mostly = {
1373 .type = cpu_to_be16(ETH_P_ARP),
1374 .func = arp_rcv,
1375};
1376
1377#ifdef CONFIG_PROC_FS
1378#if IS_ENABLED(CONFIG_AX25)
1379
1380/*
1381 * ax25 -> ASCII conversion
1382 */
1383static void ax2asc2(ax25_address *a, char *buf)
1384{
1385 char c, *s;
1386 int n;
1387
1388 for (n = 0, s = buf; n < 6; n++) {
1389 c = (a->ax25_call[n] >> 1) & 0x7F;
1390
1391 if (c != ' ')
1392 *s++ = c;
1393 }
1394
1395 *s++ = '-';
1396 n = (a->ax25_call[6] >> 1) & 0x0F;
1397 if (n > 9) {
1398 *s++ = '1';
1399 n -= 10;
1400 }
1401
1402 *s++ = n + '0';
1403 *s++ = '\0';
1404
1405 if (*buf == '\0' || *buf == '-') {
1406 buf[0] = '*';
1407 buf[1] = '\0';
1408 }
1409}
1410#endif /* CONFIG_AX25 */
1411
1412#define HBUFFERLEN 30
1413
1414static void arp_format_neigh_entry(struct seq_file *seq,
1415 struct neighbour *n)
1416{
1417 char hbuffer[HBUFFERLEN];
1418 int k, j;
1419 char tbuf[16];
1420 struct net_device *dev = n->dev;
1421 int hatype = dev->type;
1422
1423 read_lock(&n->lock);
1424 /* Convert hardware address to XX:XX:XX:XX ... form. */
1425#if IS_ENABLED(CONFIG_AX25)
1426 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1427 ax2asc2((ax25_address *)n->ha, hbuffer);
1428 else {
1429#endif
1430 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1431 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1432 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1433 hbuffer[k++] = ':';
1434 }
1435 if (k != 0)
1436 --k;
1437 hbuffer[k] = 0;
1438#if IS_ENABLED(CONFIG_AX25)
1439 }
1440#endif
1441 sprintf(tbuf, "%pI4", n->primary_key);
1442 seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n",
1443 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1444 read_unlock(&n->lock);
1445}
1446
1447static void arp_format_pneigh_entry(struct seq_file *seq,
1448 struct pneigh_entry *n)
1449{
1450 struct net_device *dev = n->dev;
1451 int hatype = dev ? dev->type : 0;
1452 char tbuf[16];
1453
1454 sprintf(tbuf, "%pI4", n->key);
1455 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1456 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1457 dev ? dev->name : "*");
1458}
1459
1460static int arp_seq_show(struct seq_file *seq, void *v)
1461{
1462 if (v == SEQ_START_TOKEN) {
1463 seq_puts(seq, "IP address HW type Flags "
1464 "HW address Mask Device\n");
1465 } else {
1466 struct neigh_seq_state *state = seq->private;
1467
1468 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1469 arp_format_pneigh_entry(seq, v);
1470 else
1471 arp_format_neigh_entry(seq, v);
1472 }
1473
1474 return 0;
1475}
1476
1477static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1478{
1479 /* Don't want to confuse "arp -a" w/ magic entries,
1480 * so we tell the generic iterator to skip NUD_NOARP.
1481 */
1482 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1483}
1484
1485static const struct seq_operations arp_seq_ops = {
1486 .start = arp_seq_start,
1487 .next = neigh_seq_next,
1488 .stop = neigh_seq_stop,
1489 .show = arp_seq_show,
1490};
1491#endif /* CONFIG_PROC_FS */
1492
1493static int __net_init arp_net_init(struct net *net)
1494{
1495 if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops,
1496 sizeof(struct neigh_seq_state)))
1497 return -ENOMEM;
1498 return 0;
1499}
1500
1501static void __net_exit arp_net_exit(struct net *net)
1502{
1503 remove_proc_entry("arp", net->proc_net);
1504}
1505
1506static struct pernet_operations arp_net_ops = {
1507 .init = arp_net_init,
1508 .exit = arp_net_exit,
1509};
1510
1511void __init arp_init(void)
1512{
1513 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
1514
1515 dev_add_pack(&arp_packet_type);
1516 register_pernet_subsys(&arp_net_ops);
1517#ifdef CONFIG_SYSCTL
1518 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1519#endif
1520 register_netdevice_notifier(&arp_netdev_notifier);
1521}
1/* linux/net/ipv4/arp.c
2 *
3 * Copyright (C) 1994 by Florian La Roche
4 *
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
8 * address).
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Fixes:
16 * Alan Cox : Removed the Ethernet assumptions in
17 * Florian's code
18 * Alan Cox : Fixed some small errors in the ARP
19 * logic
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
40 * Craig Schlenter : Don't modify permanent entry
41 * during arp_rcv.
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
44 * eg intelligent arp probing and
45 * generation
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
51 * Jonathan Layes : Added arpd support through kerneld
52 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
58 * Alan Cox : Took the AP1000 nasty FDDI hack and
59 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
61 * one in...
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
73 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
74 */
75
76#include <linux/module.h>
77#include <linux/types.h>
78#include <linux/string.h>
79#include <linux/kernel.h>
80#include <linux/capability.h>
81#include <linux/socket.h>
82#include <linux/sockios.h>
83#include <linux/errno.h>
84#include <linux/in.h>
85#include <linux/mm.h>
86#include <linux/inet.h>
87#include <linux/inetdevice.h>
88#include <linux/netdevice.h>
89#include <linux/etherdevice.h>
90#include <linux/fddidevice.h>
91#include <linux/if_arp.h>
92#include <linux/trdevice.h>
93#include <linux/skbuff.h>
94#include <linux/proc_fs.h>
95#include <linux/seq_file.h>
96#include <linux/stat.h>
97#include <linux/init.h>
98#include <linux/net.h>
99#include <linux/rcupdate.h>
100#include <linux/slab.h>
101#ifdef CONFIG_SYSCTL
102#include <linux/sysctl.h>
103#endif
104
105#include <net/net_namespace.h>
106#include <net/ip.h>
107#include <net/icmp.h>
108#include <net/route.h>
109#include <net/protocol.h>
110#include <net/tcp.h>
111#include <net/sock.h>
112#include <net/arp.h>
113#include <net/ax25.h>
114#include <net/netrom.h>
115#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
116#include <net/atmclip.h>
117struct neigh_table *clip_tbl_hook;
118EXPORT_SYMBOL(clip_tbl_hook);
119#endif
120
121#include <asm/system.h>
122#include <linux/uaccess.h>
123
124#include <linux/netfilter_arp.h>
125
126/*
127 * Interface to generic neighbour cache.
128 */
129static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 rnd);
130static int arp_constructor(struct neighbour *neigh);
131static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
132static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
133static void parp_redo(struct sk_buff *skb);
134
135static const struct neigh_ops arp_generic_ops = {
136 .family = AF_INET,
137 .solicit = arp_solicit,
138 .error_report = arp_error_report,
139 .output = neigh_resolve_output,
140 .connected_output = neigh_connected_output,
141};
142
143static const struct neigh_ops arp_hh_ops = {
144 .family = AF_INET,
145 .solicit = arp_solicit,
146 .error_report = arp_error_report,
147 .output = neigh_resolve_output,
148 .connected_output = neigh_resolve_output,
149};
150
151static const struct neigh_ops arp_direct_ops = {
152 .family = AF_INET,
153 .output = neigh_direct_output,
154 .connected_output = neigh_direct_output,
155};
156
157static const struct neigh_ops arp_broken_ops = {
158 .family = AF_INET,
159 .solicit = arp_solicit,
160 .error_report = arp_error_report,
161 .output = neigh_compat_output,
162 .connected_output = neigh_compat_output,
163};
164
165struct neigh_table arp_tbl = {
166 .family = AF_INET,
167 .entry_size = sizeof(struct neighbour) + 4,
168 .key_len = 4,
169 .hash = arp_hash,
170 .constructor = arp_constructor,
171 .proxy_redo = parp_redo,
172 .id = "arp_cache",
173 .parms = {
174 .tbl = &arp_tbl,
175 .base_reachable_time = 30 * HZ,
176 .retrans_time = 1 * HZ,
177 .gc_staletime = 60 * HZ,
178 .reachable_time = 30 * HZ,
179 .delay_probe_time = 5 * HZ,
180 .queue_len = 3,
181 .ucast_probes = 3,
182 .mcast_probes = 3,
183 .anycast_delay = 1 * HZ,
184 .proxy_delay = (8 * HZ) / 10,
185 .proxy_qlen = 64,
186 .locktime = 1 * HZ,
187 },
188 .gc_interval = 30 * HZ,
189 .gc_thresh1 = 128,
190 .gc_thresh2 = 512,
191 .gc_thresh3 = 1024,
192};
193EXPORT_SYMBOL(arp_tbl);
194
195int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
196{
197 switch (dev->type) {
198 case ARPHRD_ETHER:
199 case ARPHRD_FDDI:
200 case ARPHRD_IEEE802:
201 ip_eth_mc_map(addr, haddr);
202 return 0;
203 case ARPHRD_IEEE802_TR:
204 ip_tr_mc_map(addr, haddr);
205 return 0;
206 case ARPHRD_INFINIBAND:
207 ip_ib_mc_map(addr, dev->broadcast, haddr);
208 return 0;
209 case ARPHRD_IPGRE:
210 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
211 return 0;
212 default:
213 if (dir) {
214 memcpy(haddr, dev->broadcast, dev->addr_len);
215 return 0;
216 }
217 }
218 return -EINVAL;
219}
220
221
222static u32 arp_hash(const void *pkey,
223 const struct net_device *dev,
224 __u32 hash_rnd)
225{
226 return arp_hashfn(*(u32 *)pkey, dev, hash_rnd);
227}
228
229static int arp_constructor(struct neighbour *neigh)
230{
231 __be32 addr = *(__be32 *)neigh->primary_key;
232 struct net_device *dev = neigh->dev;
233 struct in_device *in_dev;
234 struct neigh_parms *parms;
235
236 rcu_read_lock();
237 in_dev = __in_dev_get_rcu(dev);
238 if (in_dev == NULL) {
239 rcu_read_unlock();
240 return -EINVAL;
241 }
242
243 neigh->type = inet_addr_type(dev_net(dev), addr);
244
245 parms = in_dev->arp_parms;
246 __neigh_parms_put(neigh->parms);
247 neigh->parms = neigh_parms_clone(parms);
248 rcu_read_unlock();
249
250 if (!dev->header_ops) {
251 neigh->nud_state = NUD_NOARP;
252 neigh->ops = &arp_direct_ops;
253 neigh->output = neigh_direct_output;
254 } else {
255 /* Good devices (checked by reading texts, but only Ethernet is
256 tested)
257
258 ARPHRD_ETHER: (ethernet, apfddi)
259 ARPHRD_FDDI: (fddi)
260 ARPHRD_IEEE802: (tr)
261 ARPHRD_METRICOM: (strip)
262 ARPHRD_ARCNET:
263 etc. etc. etc.
264
265 ARPHRD_IPDDP will also work, if author repairs it.
266 I did not it, because this driver does not work even
267 in old paradigm.
268 */
269
270#if 1
271 /* So... these "amateur" devices are hopeless.
272 The only thing, that I can say now:
273 It is very sad that we need to keep ugly obsolete
274 code to make them happy.
275
276 They should be moved to more reasonable state, now
277 they use rebuild_header INSTEAD OF hard_start_xmit!!!
278 Besides that, they are sort of out of date
279 (a lot of redundant clones/copies, useless in 2.1),
280 I wonder why people believe that they work.
281 */
282 switch (dev->type) {
283 default:
284 break;
285 case ARPHRD_ROSE:
286#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
287 case ARPHRD_AX25:
288#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
289 case ARPHRD_NETROM:
290#endif
291 neigh->ops = &arp_broken_ops;
292 neigh->output = neigh->ops->output;
293 return 0;
294#else
295 break;
296#endif
297 }
298#endif
299 if (neigh->type == RTN_MULTICAST) {
300 neigh->nud_state = NUD_NOARP;
301 arp_mc_map(addr, neigh->ha, dev, 1);
302 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
303 neigh->nud_state = NUD_NOARP;
304 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
305 } else if (neigh->type == RTN_BROADCAST ||
306 (dev->flags & IFF_POINTOPOINT)) {
307 neigh->nud_state = NUD_NOARP;
308 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
309 }
310
311 if (dev->header_ops->cache)
312 neigh->ops = &arp_hh_ops;
313 else
314 neigh->ops = &arp_generic_ops;
315
316 if (neigh->nud_state & NUD_VALID)
317 neigh->output = neigh->ops->connected_output;
318 else
319 neigh->output = neigh->ops->output;
320 }
321 return 0;
322}
323
324static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
325{
326 dst_link_failure(skb);
327 kfree_skb(skb);
328}
329
330static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
331{
332 __be32 saddr = 0;
333 u8 *dst_ha = NULL;
334 struct net_device *dev = neigh->dev;
335 __be32 target = *(__be32 *)neigh->primary_key;
336 int probes = atomic_read(&neigh->probes);
337 struct in_device *in_dev;
338
339 rcu_read_lock();
340 in_dev = __in_dev_get_rcu(dev);
341 if (!in_dev) {
342 rcu_read_unlock();
343 return;
344 }
345 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
346 default:
347 case 0: /* By default announce any local IP */
348 if (skb && inet_addr_type(dev_net(dev),
349 ip_hdr(skb)->saddr) == RTN_LOCAL)
350 saddr = ip_hdr(skb)->saddr;
351 break;
352 case 1: /* Restrict announcements of saddr in same subnet */
353 if (!skb)
354 break;
355 saddr = ip_hdr(skb)->saddr;
356 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) {
357 /* saddr should be known to target */
358 if (inet_addr_onlink(in_dev, target, saddr))
359 break;
360 }
361 saddr = 0;
362 break;
363 case 2: /* Avoid secondary IPs, get a primary/preferred one */
364 break;
365 }
366 rcu_read_unlock();
367
368 if (!saddr)
369 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
370
371 probes -= neigh->parms->ucast_probes;
372 if (probes < 0) {
373 if (!(neigh->nud_state & NUD_VALID))
374 printk(KERN_DEBUG
375 "trying to ucast probe in NUD_INVALID\n");
376 dst_ha = neigh->ha;
377 read_lock_bh(&neigh->lock);
378 } else {
379 probes -= neigh->parms->app_probes;
380 if (probes < 0) {
381#ifdef CONFIG_ARPD
382 neigh_app_ns(neigh);
383#endif
384 return;
385 }
386 }
387
388 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
389 dst_ha, dev->dev_addr, NULL);
390 if (dst_ha)
391 read_unlock_bh(&neigh->lock);
392}
393
394static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
395{
396 int scope;
397
398 switch (IN_DEV_ARP_IGNORE(in_dev)) {
399 case 0: /* Reply, the tip is already validated */
400 return 0;
401 case 1: /* Reply only if tip is configured on the incoming interface */
402 sip = 0;
403 scope = RT_SCOPE_HOST;
404 break;
405 case 2: /*
406 * Reply only if tip is configured on the incoming interface
407 * and is in same subnet as sip
408 */
409 scope = RT_SCOPE_HOST;
410 break;
411 case 3: /* Do not reply for scope host addresses */
412 sip = 0;
413 scope = RT_SCOPE_LINK;
414 break;
415 case 4: /* Reserved */
416 case 5:
417 case 6:
418 case 7:
419 return 0;
420 case 8: /* Do not reply */
421 return 1;
422 default:
423 return 0;
424 }
425 return !inet_confirm_addr(in_dev, sip, tip, scope);
426}
427
428static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
429{
430 struct rtable *rt;
431 int flag = 0;
432 /*unsigned long now; */
433 struct net *net = dev_net(dev);
434
435 rt = ip_route_output(net, sip, tip, 0, 0);
436 if (IS_ERR(rt))
437 return 1;
438 if (rt->dst.dev != dev) {
439 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
440 flag = 1;
441 }
442 ip_rt_put(rt);
443 return flag;
444}
445
446/* OBSOLETE FUNCTIONS */
447
448/*
449 * Find an arp mapping in the cache. If not found, post a request.
450 *
451 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
452 * even if it exists. It is supposed that skb->dev was mangled
453 * by a virtual device (eql, shaper). Nobody but broken devices
454 * is allowed to use this function, it is scheduled to be removed. --ANK
455 */
456
457static int arp_set_predefined(int addr_hint, unsigned char *haddr,
458 __be32 paddr, struct net_device *dev)
459{
460 switch (addr_hint) {
461 case RTN_LOCAL:
462 printk(KERN_DEBUG "ARP: arp called for own IP address\n");
463 memcpy(haddr, dev->dev_addr, dev->addr_len);
464 return 1;
465 case RTN_MULTICAST:
466 arp_mc_map(paddr, haddr, dev, 1);
467 return 1;
468 case RTN_BROADCAST:
469 memcpy(haddr, dev->broadcast, dev->addr_len);
470 return 1;
471 }
472 return 0;
473}
474
475
476int arp_find(unsigned char *haddr, struct sk_buff *skb)
477{
478 struct net_device *dev = skb->dev;
479 __be32 paddr;
480 struct neighbour *n;
481
482 if (!skb_dst(skb)) {
483 printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
484 kfree_skb(skb);
485 return 1;
486 }
487
488 paddr = skb_rtable(skb)->rt_gateway;
489
490 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr,
491 paddr, dev))
492 return 0;
493
494 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
495
496 if (n) {
497 n->used = jiffies;
498 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) {
499 neigh_ha_snapshot(haddr, n, dev);
500 neigh_release(n);
501 return 0;
502 }
503 neigh_release(n);
504 } else
505 kfree_skb(skb);
506 return 1;
507}
508EXPORT_SYMBOL(arp_find);
509
510/* END OF OBSOLETE FUNCTIONS */
511
512/*
513 * Check if we can use proxy ARP for this path
514 */
515static inline int arp_fwd_proxy(struct in_device *in_dev,
516 struct net_device *dev, struct rtable *rt)
517{
518 struct in_device *out_dev;
519 int imi, omi = -1;
520
521 if (rt->dst.dev == dev)
522 return 0;
523
524 if (!IN_DEV_PROXY_ARP(in_dev))
525 return 0;
526 imi = IN_DEV_MEDIUM_ID(in_dev);
527 if (imi == 0)
528 return 1;
529 if (imi == -1)
530 return 0;
531
532 /* place to check for proxy_arp for routes */
533
534 out_dev = __in_dev_get_rcu(rt->dst.dev);
535 if (out_dev)
536 omi = IN_DEV_MEDIUM_ID(out_dev);
537
538 return omi != imi && omi != -1;
539}
540
541/*
542 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
543 *
544 * RFC3069 supports proxy arp replies back to the same interface. This
545 * is done to support (ethernet) switch features, like RFC 3069, where
546 * the individual ports are not allowed to communicate with each
547 * other, BUT they are allowed to talk to the upstream router. As
548 * described in RFC 3069, it is possible to allow these hosts to
549 * communicate through the upstream router, by proxy_arp'ing.
550 *
551 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
552 *
553 * This technology is known by different names:
554 * In RFC 3069 it is called VLAN Aggregation.
555 * Cisco and Allied Telesyn call it Private VLAN.
556 * Hewlett-Packard call it Source-Port filtering or port-isolation.
557 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
558 *
559 */
560static inline int arp_fwd_pvlan(struct in_device *in_dev,
561 struct net_device *dev, struct rtable *rt,
562 __be32 sip, __be32 tip)
563{
564 /* Private VLAN is only concerned about the same ethernet segment */
565 if (rt->dst.dev != dev)
566 return 0;
567
568 /* Don't reply on self probes (often done by windowz boxes)*/
569 if (sip == tip)
570 return 0;
571
572 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
573 return 1;
574 else
575 return 0;
576}
577
578/*
579 * Interface to link layer: send routine and receive handler.
580 */
581
582/*
583 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
584 * message.
585 */
586struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
587 struct net_device *dev, __be32 src_ip,
588 const unsigned char *dest_hw,
589 const unsigned char *src_hw,
590 const unsigned char *target_hw)
591{
592 struct sk_buff *skb;
593 struct arphdr *arp;
594 unsigned char *arp_ptr;
595
596 /*
597 * Allocate a buffer
598 */
599
600 skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
601 if (skb == NULL)
602 return NULL;
603
604 skb_reserve(skb, LL_RESERVED_SPACE(dev));
605 skb_reset_network_header(skb);
606 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
607 skb->dev = dev;
608 skb->protocol = htons(ETH_P_ARP);
609 if (src_hw == NULL)
610 src_hw = dev->dev_addr;
611 if (dest_hw == NULL)
612 dest_hw = dev->broadcast;
613
614 /*
615 * Fill the device header for the ARP frame
616 */
617 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
618 goto out;
619
620 /*
621 * Fill out the arp protocol part.
622 *
623 * The arp hardware type should match the device type, except for FDDI,
624 * which (according to RFC 1390) should always equal 1 (Ethernet).
625 */
626 /*
627 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
628 * DIX code for the protocol. Make these device structure fields.
629 */
630 switch (dev->type) {
631 default:
632 arp->ar_hrd = htons(dev->type);
633 arp->ar_pro = htons(ETH_P_IP);
634 break;
635
636#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
637 case ARPHRD_AX25:
638 arp->ar_hrd = htons(ARPHRD_AX25);
639 arp->ar_pro = htons(AX25_P_IP);
640 break;
641
642#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
643 case ARPHRD_NETROM:
644 arp->ar_hrd = htons(ARPHRD_NETROM);
645 arp->ar_pro = htons(AX25_P_IP);
646 break;
647#endif
648#endif
649
650#if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
651 case ARPHRD_FDDI:
652 arp->ar_hrd = htons(ARPHRD_ETHER);
653 arp->ar_pro = htons(ETH_P_IP);
654 break;
655#endif
656#if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
657 case ARPHRD_IEEE802_TR:
658 arp->ar_hrd = htons(ARPHRD_IEEE802);
659 arp->ar_pro = htons(ETH_P_IP);
660 break;
661#endif
662 }
663
664 arp->ar_hln = dev->addr_len;
665 arp->ar_pln = 4;
666 arp->ar_op = htons(type);
667
668 arp_ptr = (unsigned char *)(arp + 1);
669
670 memcpy(arp_ptr, src_hw, dev->addr_len);
671 arp_ptr += dev->addr_len;
672 memcpy(arp_ptr, &src_ip, 4);
673 arp_ptr += 4;
674 if (target_hw != NULL)
675 memcpy(arp_ptr, target_hw, dev->addr_len);
676 else
677 memset(arp_ptr, 0, dev->addr_len);
678 arp_ptr += dev->addr_len;
679 memcpy(arp_ptr, &dest_ip, 4);
680
681 return skb;
682
683out:
684 kfree_skb(skb);
685 return NULL;
686}
687EXPORT_SYMBOL(arp_create);
688
689/*
690 * Send an arp packet.
691 */
692void arp_xmit(struct sk_buff *skb)
693{
694 /* Send it off, maybe filter it using firewalling first. */
695 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
696}
697EXPORT_SYMBOL(arp_xmit);
698
699/*
700 * Create and send an arp packet.
701 */
702void arp_send(int type, int ptype, __be32 dest_ip,
703 struct net_device *dev, __be32 src_ip,
704 const unsigned char *dest_hw, const unsigned char *src_hw,
705 const unsigned char *target_hw)
706{
707 struct sk_buff *skb;
708
709 /*
710 * No arp on this interface.
711 */
712
713 if (dev->flags&IFF_NOARP)
714 return;
715
716 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
717 dest_hw, src_hw, target_hw);
718 if (skb == NULL)
719 return;
720
721 arp_xmit(skb);
722}
723EXPORT_SYMBOL(arp_send);
724
725/*
726 * Process an arp request.
727 */
728
729static int arp_process(struct sk_buff *skb)
730{
731 struct net_device *dev = skb->dev;
732 struct in_device *in_dev = __in_dev_get_rcu(dev);
733 struct arphdr *arp;
734 unsigned char *arp_ptr;
735 struct rtable *rt;
736 unsigned char *sha;
737 __be32 sip, tip;
738 u16 dev_type = dev->type;
739 int addr_type;
740 struct neighbour *n;
741 struct net *net = dev_net(dev);
742
743 /* arp_rcv below verifies the ARP header and verifies the device
744 * is ARP'able.
745 */
746
747 if (in_dev == NULL)
748 goto out;
749
750 arp = arp_hdr(skb);
751
752 switch (dev_type) {
753 default:
754 if (arp->ar_pro != htons(ETH_P_IP) ||
755 htons(dev_type) != arp->ar_hrd)
756 goto out;
757 break;
758 case ARPHRD_ETHER:
759 case ARPHRD_IEEE802_TR:
760 case ARPHRD_FDDI:
761 case ARPHRD_IEEE802:
762 /*
763 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
764 * devices, according to RFC 2625) devices will accept ARP
765 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
766 * This is the case also of FDDI, where the RFC 1390 says that
767 * FDDI devices should accept ARP hardware of (1) Ethernet,
768 * however, to be more robust, we'll accept both 1 (Ethernet)
769 * or 6 (IEEE 802.2)
770 */
771 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
772 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
773 arp->ar_pro != htons(ETH_P_IP))
774 goto out;
775 break;
776 case ARPHRD_AX25:
777 if (arp->ar_pro != htons(AX25_P_IP) ||
778 arp->ar_hrd != htons(ARPHRD_AX25))
779 goto out;
780 break;
781 case ARPHRD_NETROM:
782 if (arp->ar_pro != htons(AX25_P_IP) ||
783 arp->ar_hrd != htons(ARPHRD_NETROM))
784 goto out;
785 break;
786 }
787
788 /* Understand only these message types */
789
790 if (arp->ar_op != htons(ARPOP_REPLY) &&
791 arp->ar_op != htons(ARPOP_REQUEST))
792 goto out;
793
794/*
795 * Extract fields
796 */
797 arp_ptr = (unsigned char *)(arp + 1);
798 sha = arp_ptr;
799 arp_ptr += dev->addr_len;
800 memcpy(&sip, arp_ptr, 4);
801 arp_ptr += 4;
802 arp_ptr += dev->addr_len;
803 memcpy(&tip, arp_ptr, 4);
804/*
805 * Check for bad requests for 127.x.x.x and requests for multicast
806 * addresses. If this is one such, delete it.
807 */
808 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
809 goto out;
810
811/*
812 * Special case: We must set Frame Relay source Q.922 address
813 */
814 if (dev_type == ARPHRD_DLCI)
815 sha = dev->broadcast;
816
817/*
818 * Process entry. The idea here is we want to send a reply if it is a
819 * request for us or if it is a request for someone else that we hold
820 * a proxy for. We want to add an entry to our cache if it is a reply
821 * to us or if it is a request for our address.
822 * (The assumption for this last is that if someone is requesting our
823 * address, they are probably intending to talk to us, so it saves time
824 * if we cache their address. Their address is also probably not in
825 * our cache, since ours is not in their cache.)
826 *
827 * Putting this another way, we only care about replies if they are to
828 * us, in which case we add them to the cache. For requests, we care
829 * about those for us and those for our proxies. We reply to both,
830 * and in the case of requests for us we add the requester to the arp
831 * cache.
832 */
833
834 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
835 if (sip == 0) {
836 if (arp->ar_op == htons(ARPOP_REQUEST) &&
837 inet_addr_type(net, tip) == RTN_LOCAL &&
838 !arp_ignore(in_dev, sip, tip))
839 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
840 dev->dev_addr, sha);
841 goto out;
842 }
843
844 if (arp->ar_op == htons(ARPOP_REQUEST) &&
845 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
846
847 rt = skb_rtable(skb);
848 addr_type = rt->rt_type;
849
850 if (addr_type == RTN_LOCAL) {
851 int dont_send;
852
853 dont_send = arp_ignore(in_dev, sip, tip);
854 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
855 dont_send = arp_filter(sip, tip, dev);
856 if (!dont_send) {
857 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
858 if (n) {
859 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
860 dev, tip, sha, dev->dev_addr,
861 sha);
862 neigh_release(n);
863 }
864 }
865 goto out;
866 } else if (IN_DEV_FORWARD(in_dev)) {
867 if (addr_type == RTN_UNICAST &&
868 (arp_fwd_proxy(in_dev, dev, rt) ||
869 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
870 pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) {
871 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
872 if (n)
873 neigh_release(n);
874
875 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
876 skb->pkt_type == PACKET_HOST ||
877 in_dev->arp_parms->proxy_delay == 0) {
878 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
879 dev, tip, sha, dev->dev_addr,
880 sha);
881 } else {
882 pneigh_enqueue(&arp_tbl,
883 in_dev->arp_parms, skb);
884 return 0;
885 }
886 goto out;
887 }
888 }
889 }
890
891 /* Update our ARP tables */
892
893 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
894
895 if (IPV4_DEVCONF_ALL(dev_net(dev), ARP_ACCEPT)) {
896 /* Unsolicited ARP is not accepted by default.
897 It is possible, that this option should be enabled for some
898 devices (strip is candidate)
899 */
900 if (n == NULL &&
901 (arp->ar_op == htons(ARPOP_REPLY) ||
902 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) &&
903 inet_addr_type(net, sip) == RTN_UNICAST)
904 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
905 }
906
907 if (n) {
908 int state = NUD_REACHABLE;
909 int override;
910
911 /* If several different ARP replies follows back-to-back,
912 use the FIRST one. It is possible, if several proxy
913 agents are active. Taking the first reply prevents
914 arp trashing and chooses the fastest router.
915 */
916 override = time_after(jiffies, n->updated + n->parms->locktime);
917
918 /* Broadcast replies and request packets
919 do not assert neighbour reachability.
920 */
921 if (arp->ar_op != htons(ARPOP_REPLY) ||
922 skb->pkt_type != PACKET_HOST)
923 state = NUD_STALE;
924 neigh_update(n, sha, state,
925 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
926 neigh_release(n);
927 }
928
929out:
930 consume_skb(skb);
931 return 0;
932}
933
934static void parp_redo(struct sk_buff *skb)
935{
936 arp_process(skb);
937}
938
939
940/*
941 * Receive an arp request from the device layer.
942 */
943
944static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
945 struct packet_type *pt, struct net_device *orig_dev)
946{
947 struct arphdr *arp;
948
949 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
950 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
951 goto freeskb;
952
953 arp = arp_hdr(skb);
954 if (arp->ar_hln != dev->addr_len ||
955 dev->flags & IFF_NOARP ||
956 skb->pkt_type == PACKET_OTHERHOST ||
957 skb->pkt_type == PACKET_LOOPBACK ||
958 arp->ar_pln != 4)
959 goto freeskb;
960
961 skb = skb_share_check(skb, GFP_ATOMIC);
962 if (skb == NULL)
963 goto out_of_mem;
964
965 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
966
967 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
968
969freeskb:
970 kfree_skb(skb);
971out_of_mem:
972 return 0;
973}
974
975/*
976 * User level interface (ioctl)
977 */
978
979/*
980 * Set (create) an ARP cache entry.
981 */
982
983static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
984{
985 if (dev == NULL) {
986 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
987 return 0;
988 }
989 if (__in_dev_get_rtnl(dev)) {
990 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
991 return 0;
992 }
993 return -ENXIO;
994}
995
996static int arp_req_set_public(struct net *net, struct arpreq *r,
997 struct net_device *dev)
998{
999 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1000 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1001
1002 if (mask && mask != htonl(0xFFFFFFFF))
1003 return -EINVAL;
1004 if (!dev && (r->arp_flags & ATF_COM)) {
1005 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1006 r->arp_ha.sa_data);
1007 if (!dev)
1008 return -ENODEV;
1009 }
1010 if (mask) {
1011 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL)
1012 return -ENOBUFS;
1013 return 0;
1014 }
1015
1016 return arp_req_set_proxy(net, dev, 1);
1017}
1018
1019static int arp_req_set(struct net *net, struct arpreq *r,
1020 struct net_device *dev)
1021{
1022 __be32 ip;
1023 struct neighbour *neigh;
1024 int err;
1025
1026 if (r->arp_flags & ATF_PUBL)
1027 return arp_req_set_public(net, r, dev);
1028
1029 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1030 if (r->arp_flags & ATF_PERM)
1031 r->arp_flags |= ATF_COM;
1032 if (dev == NULL) {
1033 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1034
1035 if (IS_ERR(rt))
1036 return PTR_ERR(rt);
1037 dev = rt->dst.dev;
1038 ip_rt_put(rt);
1039 if (!dev)
1040 return -EINVAL;
1041 }
1042 switch (dev->type) {
1043#if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE)
1044 case ARPHRD_FDDI:
1045 /*
1046 * According to RFC 1390, FDDI devices should accept ARP
1047 * hardware types of 1 (Ethernet). However, to be more
1048 * robust, we'll accept hardware types of either 1 (Ethernet)
1049 * or 6 (IEEE 802.2).
1050 */
1051 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1052 r->arp_ha.sa_family != ARPHRD_ETHER &&
1053 r->arp_ha.sa_family != ARPHRD_IEEE802)
1054 return -EINVAL;
1055 break;
1056#endif
1057 default:
1058 if (r->arp_ha.sa_family != dev->type)
1059 return -EINVAL;
1060 break;
1061 }
1062
1063 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1064 err = PTR_ERR(neigh);
1065 if (!IS_ERR(neigh)) {
1066 unsigned state = NUD_STALE;
1067 if (r->arp_flags & ATF_PERM)
1068 state = NUD_PERMANENT;
1069 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1070 r->arp_ha.sa_data : NULL, state,
1071 NEIGH_UPDATE_F_OVERRIDE |
1072 NEIGH_UPDATE_F_ADMIN);
1073 neigh_release(neigh);
1074 }
1075 return err;
1076}
1077
1078static unsigned arp_state_to_flags(struct neighbour *neigh)
1079{
1080 if (neigh->nud_state&NUD_PERMANENT)
1081 return ATF_PERM | ATF_COM;
1082 else if (neigh->nud_state&NUD_VALID)
1083 return ATF_COM;
1084 else
1085 return 0;
1086}
1087
1088/*
1089 * Get an ARP cache entry.
1090 */
1091
1092static int arp_req_get(struct arpreq *r, struct net_device *dev)
1093{
1094 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1095 struct neighbour *neigh;
1096 int err = -ENXIO;
1097
1098 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1099 if (neigh) {
1100 read_lock_bh(&neigh->lock);
1101 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1102 r->arp_flags = arp_state_to_flags(neigh);
1103 read_unlock_bh(&neigh->lock);
1104 r->arp_ha.sa_family = dev->type;
1105 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1106 neigh_release(neigh);
1107 err = 0;
1108 }
1109 return err;
1110}
1111
1112int arp_invalidate(struct net_device *dev, __be32 ip)
1113{
1114 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1115 int err = -ENXIO;
1116
1117 if (neigh) {
1118 if (neigh->nud_state & ~NUD_NOARP)
1119 err = neigh_update(neigh, NULL, NUD_FAILED,
1120 NEIGH_UPDATE_F_OVERRIDE|
1121 NEIGH_UPDATE_F_ADMIN);
1122 neigh_release(neigh);
1123 }
1124
1125 return err;
1126}
1127EXPORT_SYMBOL(arp_invalidate);
1128
1129static int arp_req_delete_public(struct net *net, struct arpreq *r,
1130 struct net_device *dev)
1131{
1132 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1133 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1134
1135 if (mask == htonl(0xFFFFFFFF))
1136 return pneigh_delete(&arp_tbl, net, &ip, dev);
1137
1138 if (mask)
1139 return -EINVAL;
1140
1141 return arp_req_set_proxy(net, dev, 0);
1142}
1143
1144static int arp_req_delete(struct net *net, struct arpreq *r,
1145 struct net_device *dev)
1146{
1147 __be32 ip;
1148
1149 if (r->arp_flags & ATF_PUBL)
1150 return arp_req_delete_public(net, r, dev);
1151
1152 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1153 if (dev == NULL) {
1154 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1155 if (IS_ERR(rt))
1156 return PTR_ERR(rt);
1157 dev = rt->dst.dev;
1158 ip_rt_put(rt);
1159 if (!dev)
1160 return -EINVAL;
1161 }
1162 return arp_invalidate(dev, ip);
1163}
1164
1165/*
1166 * Handle an ARP layer I/O control request.
1167 */
1168
1169int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1170{
1171 int err;
1172 struct arpreq r;
1173 struct net_device *dev = NULL;
1174
1175 switch (cmd) {
1176 case SIOCDARP:
1177 case SIOCSARP:
1178 if (!capable(CAP_NET_ADMIN))
1179 return -EPERM;
1180 case SIOCGARP:
1181 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1182 if (err)
1183 return -EFAULT;
1184 break;
1185 default:
1186 return -EINVAL;
1187 }
1188
1189 if (r.arp_pa.sa_family != AF_INET)
1190 return -EPFNOSUPPORT;
1191
1192 if (!(r.arp_flags & ATF_PUBL) &&
1193 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1194 return -EINVAL;
1195 if (!(r.arp_flags & ATF_NETMASK))
1196 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1197 htonl(0xFFFFFFFFUL);
1198 rtnl_lock();
1199 if (r.arp_dev[0]) {
1200 err = -ENODEV;
1201 dev = __dev_get_by_name(net, r.arp_dev);
1202 if (dev == NULL)
1203 goto out;
1204
1205 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1206 if (!r.arp_ha.sa_family)
1207 r.arp_ha.sa_family = dev->type;
1208 err = -EINVAL;
1209 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1210 goto out;
1211 } else if (cmd == SIOCGARP) {
1212 err = -ENODEV;
1213 goto out;
1214 }
1215
1216 switch (cmd) {
1217 case SIOCDARP:
1218 err = arp_req_delete(net, &r, dev);
1219 break;
1220 case SIOCSARP:
1221 err = arp_req_set(net, &r, dev);
1222 break;
1223 case SIOCGARP:
1224 err = arp_req_get(&r, dev);
1225 break;
1226 }
1227out:
1228 rtnl_unlock();
1229 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1230 err = -EFAULT;
1231 return err;
1232}
1233
1234static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1235 void *ptr)
1236{
1237 struct net_device *dev = ptr;
1238
1239 switch (event) {
1240 case NETDEV_CHANGEADDR:
1241 neigh_changeaddr(&arp_tbl, dev);
1242 rt_cache_flush(dev_net(dev), 0);
1243 break;
1244 default:
1245 break;
1246 }
1247
1248 return NOTIFY_DONE;
1249}
1250
1251static struct notifier_block arp_netdev_notifier = {
1252 .notifier_call = arp_netdev_event,
1253};
1254
1255/* Note, that it is not on notifier chain.
1256 It is necessary, that this routine was called after route cache will be
1257 flushed.
1258 */
1259void arp_ifdown(struct net_device *dev)
1260{
1261 neigh_ifdown(&arp_tbl, dev);
1262}
1263
1264
1265/*
1266 * Called once on startup.
1267 */
1268
1269static struct packet_type arp_packet_type __read_mostly = {
1270 .type = cpu_to_be16(ETH_P_ARP),
1271 .func = arp_rcv,
1272};
1273
1274static int arp_proc_init(void);
1275
1276void __init arp_init(void)
1277{
1278 neigh_table_init(&arp_tbl);
1279
1280 dev_add_pack(&arp_packet_type);
1281 arp_proc_init();
1282#ifdef CONFIG_SYSCTL
1283 neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL);
1284#endif
1285 register_netdevice_notifier(&arp_netdev_notifier);
1286}
1287
1288#ifdef CONFIG_PROC_FS
1289#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1290
1291/* ------------------------------------------------------------------------ */
1292/*
1293 * ax25 -> ASCII conversion
1294 */
1295static char *ax2asc2(ax25_address *a, char *buf)
1296{
1297 char c, *s;
1298 int n;
1299
1300 for (n = 0, s = buf; n < 6; n++) {
1301 c = (a->ax25_call[n] >> 1) & 0x7F;
1302
1303 if (c != ' ')
1304 *s++ = c;
1305 }
1306
1307 *s++ = '-';
1308 n = (a->ax25_call[6] >> 1) & 0x0F;
1309 if (n > 9) {
1310 *s++ = '1';
1311 n -= 10;
1312 }
1313
1314 *s++ = n + '0';
1315 *s++ = '\0';
1316
1317 if (*buf == '\0' || *buf == '-')
1318 return "*";
1319
1320 return buf;
1321}
1322#endif /* CONFIG_AX25 */
1323
1324#define HBUFFERLEN 30
1325
1326static void arp_format_neigh_entry(struct seq_file *seq,
1327 struct neighbour *n)
1328{
1329 char hbuffer[HBUFFERLEN];
1330 int k, j;
1331 char tbuf[16];
1332 struct net_device *dev = n->dev;
1333 int hatype = dev->type;
1334
1335 read_lock(&n->lock);
1336 /* Convert hardware address to XX:XX:XX:XX ... form. */
1337#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1338 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1339 ax2asc2((ax25_address *)n->ha, hbuffer);
1340 else {
1341#endif
1342 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1343 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1344 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1345 hbuffer[k++] = ':';
1346 }
1347 if (k != 0)
1348 --k;
1349 hbuffer[k] = 0;
1350#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1351 }
1352#endif
1353 sprintf(tbuf, "%pI4", n->primary_key);
1354 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1355 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1356 read_unlock(&n->lock);
1357}
1358
1359static void arp_format_pneigh_entry(struct seq_file *seq,
1360 struct pneigh_entry *n)
1361{
1362 struct net_device *dev = n->dev;
1363 int hatype = dev ? dev->type : 0;
1364 char tbuf[16];
1365
1366 sprintf(tbuf, "%pI4", n->key);
1367 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1368 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1369 dev ? dev->name : "*");
1370}
1371
1372static int arp_seq_show(struct seq_file *seq, void *v)
1373{
1374 if (v == SEQ_START_TOKEN) {
1375 seq_puts(seq, "IP address HW type Flags "
1376 "HW address Mask Device\n");
1377 } else {
1378 struct neigh_seq_state *state = seq->private;
1379
1380 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1381 arp_format_pneigh_entry(seq, v);
1382 else
1383 arp_format_neigh_entry(seq, v);
1384 }
1385
1386 return 0;
1387}
1388
1389static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1390{
1391 /* Don't want to confuse "arp -a" w/ magic entries,
1392 * so we tell the generic iterator to skip NUD_NOARP.
1393 */
1394 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1395}
1396
1397/* ------------------------------------------------------------------------ */
1398
1399static const struct seq_operations arp_seq_ops = {
1400 .start = arp_seq_start,
1401 .next = neigh_seq_next,
1402 .stop = neigh_seq_stop,
1403 .show = arp_seq_show,
1404};
1405
1406static int arp_seq_open(struct inode *inode, struct file *file)
1407{
1408 return seq_open_net(inode, file, &arp_seq_ops,
1409 sizeof(struct neigh_seq_state));
1410}
1411
1412static const struct file_operations arp_seq_fops = {
1413 .owner = THIS_MODULE,
1414 .open = arp_seq_open,
1415 .read = seq_read,
1416 .llseek = seq_lseek,
1417 .release = seq_release_net,
1418};
1419
1420
1421static int __net_init arp_net_init(struct net *net)
1422{
1423 if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops))
1424 return -ENOMEM;
1425 return 0;
1426}
1427
1428static void __net_exit arp_net_exit(struct net *net)
1429{
1430 proc_net_remove(net, "arp");
1431}
1432
1433static struct pernet_operations arp_net_ops = {
1434 .init = arp_net_init,
1435 .exit = arp_net_exit,
1436};
1437
1438static int __init arp_proc_init(void)
1439{
1440 return register_pernet_subsys(&arp_net_ops);
1441}
1442
1443#else /* CONFIG_PROC_FS */
1444
1445static int __init arp_proc_init(void)
1446{
1447 return 0;
1448}
1449
1450#endif /* CONFIG_PROC_FS */