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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
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] = 64 * 1024,
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 = *(__be32 *)neigh->primary_key;
227 struct net_device *dev = neigh->dev;
228 struct in_device *in_dev;
229 struct neigh_parms *parms;
230
231 rcu_read_lock();
232 in_dev = __in_dev_get_rcu(dev);
233 if (!in_dev) {
234 rcu_read_unlock();
235 return -EINVAL;
236 }
237
238 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
239
240 parms = in_dev->arp_parms;
241 __neigh_parms_put(neigh->parms);
242 neigh->parms = neigh_parms_clone(parms);
243 rcu_read_unlock();
244
245 if (!dev->header_ops) {
246 neigh->nud_state = NUD_NOARP;
247 neigh->ops = &arp_direct_ops;
248 neigh->output = neigh_direct_output;
249 } else {
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265 if (neigh->type == RTN_MULTICAST) {
266 neigh->nud_state = NUD_NOARP;
267 arp_mc_map(addr, neigh->ha, dev, 1);
268 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
269 neigh->nud_state = NUD_NOARP;
270 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
271 } else if (neigh->type == RTN_BROADCAST ||
272 (dev->flags & IFF_POINTOPOINT)) {
273 neigh->nud_state = NUD_NOARP;
274 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
275 }
276
277 if (dev->header_ops->cache)
278 neigh->ops = &arp_hh_ops;
279 else
280 neigh->ops = &arp_generic_ops;
281
282 if (neigh->nud_state & NUD_VALID)
283 neigh->output = neigh->ops->connected_output;
284 else
285 neigh->output = neigh->ops->output;
286 }
287 return 0;
288}
289
290static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
291{
292 dst_link_failure(skb);
293 kfree_skb(skb);
294}
295
296
297static void arp_send_dst(int type, int ptype, __be32 dest_ip,
298 struct net_device *dev, __be32 src_ip,
299 const unsigned char *dest_hw,
300 const unsigned char *src_hw,
301 const unsigned char *target_hw,
302 struct dst_entry *dst)
303{
304 struct sk_buff *skb;
305
306
307 if (dev->flags & IFF_NOARP)
308 return;
309
310 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
311 dest_hw, src_hw, target_hw);
312 if (!skb)
313 return;
314
315 skb_dst_set(skb, dst_clone(dst));
316 arp_xmit(skb);
317}
318
319void arp_send(int type, int ptype, __be32 dest_ip,
320 struct net_device *dev, __be32 src_ip,
321 const unsigned char *dest_hw, const unsigned char *src_hw,
322 const unsigned char *target_hw)
323{
324 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
325 target_hw, NULL);
326}
327EXPORT_SYMBOL(arp_send);
328
329static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
330{
331 __be32 saddr = 0;
332 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
333 struct net_device *dev = neigh->dev;
334 __be32 target = *(__be32 *)neigh->primary_key;
335 int probes = atomic_read(&neigh->probes);
336 struct in_device *in_dev;
337 struct dst_entry *dst = NULL;
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:
348 if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
349 ip_hdr(skb)->saddr) == RTN_LOCAL)
350 saddr = ip_hdr(skb)->saddr;
351 break;
352 case 1:
353 if (!skb)
354 break;
355 saddr = ip_hdr(skb)->saddr;
356 if (inet_addr_type_dev_table(dev_net(dev), dev,
357 saddr) == RTN_LOCAL) {
358
359 if (inet_addr_onlink(in_dev, target, saddr))
360 break;
361 }
362 saddr = 0;
363 break;
364 case 2:
365 break;
366 }
367 rcu_read_unlock();
368
369 if (!saddr)
370 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
371
372 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
373 if (probes < 0) {
374 if (!(neigh->nud_state & NUD_VALID))
375 pr_debug("trying to ucast probe in NUD_INVALID\n");
376 neigh_ha_snapshot(dst_ha, neigh, dev);
377 dst_hw = dst_ha;
378 } else {
379 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
380 if (probes < 0) {
381 neigh_app_ns(neigh);
382 return;
383 }
384 }
385
386 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
387 dst = skb_dst(skb);
388 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
389 dst_hw, dev->dev_addr, NULL, dst);
390}
391
392static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
393{
394 struct net *net = dev_net(in_dev->dev);
395 int scope;
396
397 switch (IN_DEV_ARP_IGNORE(in_dev)) {
398 case 0:
399 return 0;
400 case 1:
401 sip = 0;
402 scope = RT_SCOPE_HOST;
403 break;
404 case 2:
405
406
407
408 scope = RT_SCOPE_HOST;
409 break;
410 case 3:
411 sip = 0;
412 scope = RT_SCOPE_LINK;
413 in_dev = NULL;
414 break;
415 case 4:
416 case 5:
417 case 6:
418 case 7:
419 return 0;
420 case 8:
421 return 1;
422 default:
423 return 0;
424 }
425 return !inet_confirm_addr(net, 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
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
447
448
449static inline int arp_fwd_proxy(struct in_device *in_dev,
450 struct net_device *dev, struct rtable *rt)
451{
452 struct in_device *out_dev;
453 int imi, omi = -1;
454
455 if (rt->dst.dev == dev)
456 return 0;
457
458 if (!IN_DEV_PROXY_ARP(in_dev))
459 return 0;
460 imi = IN_DEV_MEDIUM_ID(in_dev);
461 if (imi == 0)
462 return 1;
463 if (imi == -1)
464 return 0;
465
466
467
468 out_dev = __in_dev_get_rcu(rt->dst.dev);
469 if (out_dev)
470 omi = IN_DEV_MEDIUM_ID(out_dev);
471
472 return omi != imi && omi != -1;
473}
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494static inline int arp_fwd_pvlan(struct in_device *in_dev,
495 struct net_device *dev, struct rtable *rt,
496 __be32 sip, __be32 tip)
497{
498
499 if (rt->dst.dev != dev)
500 return 0;
501
502
503 if (sip == tip)
504 return 0;
505
506 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
507 return 1;
508 else
509 return 0;
510}
511
512
513
514
515
516
517
518
519
520struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
521 struct net_device *dev, __be32 src_ip,
522 const unsigned char *dest_hw,
523 const unsigned char *src_hw,
524 const unsigned char *target_hw)
525{
526 struct sk_buff *skb;
527 struct arphdr *arp;
528 unsigned char *arp_ptr;
529 int hlen = LL_RESERVED_SPACE(dev);
530 int tlen = dev->needed_tailroom;
531
532
533
534
535
536 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
537 if (!skb)
538 return NULL;
539
540 skb_reserve(skb, hlen);
541 skb_reset_network_header(skb);
542 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
543 skb->dev = dev;
544 skb->protocol = htons(ETH_P_ARP);
545 if (!src_hw)
546 src_hw = dev->dev_addr;
547 if (!dest_hw)
548 dest_hw = dev->broadcast;
549
550
551
552
553 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
554 goto out;
555
556
557
558
559
560
561
562
563
564
565
566 switch (dev->type) {
567 default:
568 arp->ar_hrd = htons(dev->type);
569 arp->ar_pro = htons(ETH_P_IP);
570 break;
571
572#if IS_ENABLED(CONFIG_AX25)
573 case ARPHRD_AX25:
574 arp->ar_hrd = htons(ARPHRD_AX25);
575 arp->ar_pro = htons(AX25_P_IP);
576 break;
577
578#if IS_ENABLED(CONFIG_NETROM)
579 case ARPHRD_NETROM:
580 arp->ar_hrd = htons(ARPHRD_NETROM);
581 arp->ar_pro = htons(AX25_P_IP);
582 break;
583#endif
584#endif
585
586#if IS_ENABLED(CONFIG_FDDI)
587 case ARPHRD_FDDI:
588 arp->ar_hrd = htons(ARPHRD_ETHER);
589 arp->ar_pro = htons(ETH_P_IP);
590 break;
591#endif
592 }
593
594 arp->ar_hln = dev->addr_len;
595 arp->ar_pln = 4;
596 arp->ar_op = htons(type);
597
598 arp_ptr = (unsigned char *)(arp + 1);
599
600 memcpy(arp_ptr, src_hw, dev->addr_len);
601 arp_ptr += dev->addr_len;
602 memcpy(arp_ptr, &src_ip, 4);
603 arp_ptr += 4;
604
605 switch (dev->type) {
606#if IS_ENABLED(CONFIG_FIREWIRE_NET)
607 case ARPHRD_IEEE1394:
608 break;
609#endif
610 default:
611 if (target_hw)
612 memcpy(arp_ptr, target_hw, dev->addr_len);
613 else
614 memset(arp_ptr, 0, dev->addr_len);
615 arp_ptr += dev->addr_len;
616 }
617 memcpy(arp_ptr, &dest_ip, 4);
618
619 return skb;
620
621out:
622 kfree_skb(skb);
623 return NULL;
624}
625EXPORT_SYMBOL(arp_create);
626
627static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
628{
629 return dev_queue_xmit(skb);
630}
631
632
633
634
635void arp_xmit(struct sk_buff *skb)
636{
637
638 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
639 dev_net(skb->dev), NULL, skb, NULL, skb->dev,
640 arp_xmit_finish);
641}
642EXPORT_SYMBOL(arp_xmit);
643
644
645
646
647
648static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
649{
650 struct net_device *dev = skb->dev;
651 struct in_device *in_dev = __in_dev_get_rcu(dev);
652 struct arphdr *arp;
653 unsigned char *arp_ptr;
654 struct rtable *rt;
655 unsigned char *sha;
656 __be32 sip, tip;
657 u16 dev_type = dev->type;
658 int addr_type;
659 struct neighbour *n;
660 struct dst_entry *reply_dst = NULL;
661 bool is_garp = false;
662
663
664
665
666
667 if (!in_dev)
668 goto out;
669
670 arp = arp_hdr(skb);
671
672 switch (dev_type) {
673 default:
674 if (arp->ar_pro != htons(ETH_P_IP) ||
675 htons(dev_type) != arp->ar_hrd)
676 goto out;
677 break;
678 case ARPHRD_ETHER:
679 case ARPHRD_FDDI:
680 case ARPHRD_IEEE802:
681
682
683
684
685
686
687
688
689
690 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
691 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
692 arp->ar_pro != htons(ETH_P_IP))
693 goto out;
694 break;
695 case ARPHRD_AX25:
696 if (arp->ar_pro != htons(AX25_P_IP) ||
697 arp->ar_hrd != htons(ARPHRD_AX25))
698 goto out;
699 break;
700 case ARPHRD_NETROM:
701 if (arp->ar_pro != htons(AX25_P_IP) ||
702 arp->ar_hrd != htons(ARPHRD_NETROM))
703 goto out;
704 break;
705 }
706
707
708
709 if (arp->ar_op != htons(ARPOP_REPLY) &&
710 arp->ar_op != htons(ARPOP_REQUEST))
711 goto out;
712
713
714
715
716 arp_ptr = (unsigned char *)(arp + 1);
717 sha = arp_ptr;
718 arp_ptr += dev->addr_len;
719 memcpy(&sip, arp_ptr, 4);
720 arp_ptr += 4;
721 switch (dev_type) {
722#if IS_ENABLED(CONFIG_FIREWIRE_NET)
723 case ARPHRD_IEEE1394:
724 break;
725#endif
726 default:
727 arp_ptr += dev->addr_len;
728 }
729 memcpy(&tip, arp_ptr, 4);
730
731
732
733
734 if (ipv4_is_multicast(tip) ||
735 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
736 goto out;
737
738
739
740
741 if (dev_type == ARPHRD_DLCI)
742 sha = dev->broadcast;
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
762 reply_dst = (struct dst_entry *)
763 iptunnel_metadata_reply(skb_metadata_dst(skb),
764 GFP_ATOMIC);
765
766
767 if (sip == 0) {
768 if (arp->ar_op == htons(ARPOP_REQUEST) &&
769 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
770 !arp_ignore(in_dev, sip, tip))
771 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
772 sha, dev->dev_addr, sha, reply_dst);
773 goto out;
774 }
775
776 if (arp->ar_op == htons(ARPOP_REQUEST) &&
777 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
778
779 rt = skb_rtable(skb);
780 addr_type = rt->rt_type;
781
782 if (addr_type == RTN_LOCAL) {
783 int dont_send;
784
785 dont_send = arp_ignore(in_dev, sip, tip);
786 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
787 dont_send = arp_filter(sip, tip, dev);
788 if (!dont_send) {
789 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
790 if (n) {
791 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
792 sip, dev, tip, sha,
793 dev->dev_addr, sha,
794 reply_dst);
795 neigh_release(n);
796 }
797 }
798 goto out;
799 } else if (IN_DEV_FORWARD(in_dev)) {
800 if (addr_type == RTN_UNICAST &&
801 (arp_fwd_proxy(in_dev, dev, rt) ||
802 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
803 (rt->dst.dev != dev &&
804 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
805 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
806 if (n)
807 neigh_release(n);
808
809 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
810 skb->pkt_type == PACKET_HOST ||
811 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
812 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
813 sip, dev, tip, sha,
814 dev->dev_addr, sha,
815 reply_dst);
816 } else {
817 pneigh_enqueue(&arp_tbl,
818 in_dev->arp_parms, skb);
819 goto out_free_dst;
820 }
821 goto out;
822 }
823 }
824 }
825
826
827
828 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
829
830 if (IN_DEV_ARP_ACCEPT(in_dev)) {
831 unsigned int addr_type = inet_addr_type_dev_table(net, dev, sip);
832
833
834
835
836
837 is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip &&
838 addr_type == RTN_UNICAST;
839
840 if (!n &&
841 ((arp->ar_op == htons(ARPOP_REPLY) &&
842 addr_type == RTN_UNICAST) || is_garp))
843 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
844 }
845
846 if (n) {
847 int state = NUD_REACHABLE;
848 int override;
849
850
851
852
853
854
855 override = time_after(jiffies,
856 n->updated +
857 NEIGH_VAR(n->parms, LOCKTIME)) ||
858 is_garp;
859
860
861
862
863 if (arp->ar_op != htons(ARPOP_REPLY) ||
864 skb->pkt_type != PACKET_HOST)
865 state = NUD_STALE;
866 neigh_update(n, sha, state,
867 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
868 neigh_release(n);
869 }
870
871out:
872 consume_skb(skb);
873out_free_dst:
874 dst_release(reply_dst);
875 return 0;
876}
877
878static void parp_redo(struct sk_buff *skb)
879{
880 arp_process(dev_net(skb->dev), NULL, skb);
881}
882
883
884
885
886
887
888static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
889 struct packet_type *pt, struct net_device *orig_dev)
890{
891 const struct arphdr *arp;
892
893
894 if (dev->flags & IFF_NOARP ||
895 skb->pkt_type == PACKET_OTHERHOST ||
896 skb->pkt_type == PACKET_LOOPBACK)
897 goto consumeskb;
898
899 skb = skb_share_check(skb, GFP_ATOMIC);
900 if (!skb)
901 goto out_of_mem;
902
903
904 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
905 goto freeskb;
906
907 arp = arp_hdr(skb);
908 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
909 goto freeskb;
910
911 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
912
913 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
914 dev_net(dev), NULL, skb, dev, NULL,
915 arp_process);
916
917consumeskb:
918 consume_skb(skb);
919 return 0;
920freeskb:
921 kfree_skb(skb);
922out_of_mem:
923 return 0;
924}
925
926
927
928
929
930
931
932
933
934static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
935{
936 if (!dev) {
937 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
938 return 0;
939 }
940 if (__in_dev_get_rtnl(dev)) {
941 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
942 return 0;
943 }
944 return -ENXIO;
945}
946
947static int arp_req_set_public(struct net *net, struct arpreq *r,
948 struct net_device *dev)
949{
950 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
951 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
952
953 if (mask && mask != htonl(0xFFFFFFFF))
954 return -EINVAL;
955 if (!dev && (r->arp_flags & ATF_COM)) {
956 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
957 r->arp_ha.sa_data);
958 if (!dev)
959 return -ENODEV;
960 }
961 if (mask) {
962 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
963 return -ENOBUFS;
964 return 0;
965 }
966
967 return arp_req_set_proxy(net, dev, 1);
968}
969
970static int arp_req_set(struct net *net, struct arpreq *r,
971 struct net_device *dev)
972{
973 __be32 ip;
974 struct neighbour *neigh;
975 int err;
976
977 if (r->arp_flags & ATF_PUBL)
978 return arp_req_set_public(net, r, dev);
979
980 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
981 if (r->arp_flags & ATF_PERM)
982 r->arp_flags |= ATF_COM;
983 if (!dev) {
984 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
985
986 if (IS_ERR(rt))
987 return PTR_ERR(rt);
988 dev = rt->dst.dev;
989 ip_rt_put(rt);
990 if (!dev)
991 return -EINVAL;
992 }
993 switch (dev->type) {
994#if IS_ENABLED(CONFIG_FDDI)
995 case ARPHRD_FDDI:
996
997
998
999
1000
1001
1002 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1003 r->arp_ha.sa_family != ARPHRD_ETHER &&
1004 r->arp_ha.sa_family != ARPHRD_IEEE802)
1005 return -EINVAL;
1006 break;
1007#endif
1008 default:
1009 if (r->arp_ha.sa_family != dev->type)
1010 return -EINVAL;
1011 break;
1012 }
1013
1014 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1015 err = PTR_ERR(neigh);
1016 if (!IS_ERR(neigh)) {
1017 unsigned int state = NUD_STALE;
1018 if (r->arp_flags & ATF_PERM)
1019 state = NUD_PERMANENT;
1020 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1021 r->arp_ha.sa_data : NULL, state,
1022 NEIGH_UPDATE_F_OVERRIDE |
1023 NEIGH_UPDATE_F_ADMIN);
1024 neigh_release(neigh);
1025 }
1026 return err;
1027}
1028
1029static unsigned int arp_state_to_flags(struct neighbour *neigh)
1030{
1031 if (neigh->nud_state&NUD_PERMANENT)
1032 return ATF_PERM | ATF_COM;
1033 else if (neigh->nud_state&NUD_VALID)
1034 return ATF_COM;
1035 else
1036 return 0;
1037}
1038
1039
1040
1041
1042
1043static int arp_req_get(struct arpreq *r, struct net_device *dev)
1044{
1045 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1046 struct neighbour *neigh;
1047 int err = -ENXIO;
1048
1049 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1050 if (neigh) {
1051 if (!(neigh->nud_state & NUD_NOARP)) {
1052 read_lock_bh(&neigh->lock);
1053 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1054 r->arp_flags = arp_state_to_flags(neigh);
1055 read_unlock_bh(&neigh->lock);
1056 r->arp_ha.sa_family = dev->type;
1057 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1058 err = 0;
1059 }
1060 neigh_release(neigh);
1061 }
1062 return err;
1063}
1064
1065static int arp_invalidate(struct net_device *dev, __be32 ip)
1066{
1067 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1068 int err = -ENXIO;
1069
1070 if (neigh) {
1071 if (neigh->nud_state & ~NUD_NOARP)
1072 err = neigh_update(neigh, NULL, NUD_FAILED,
1073 NEIGH_UPDATE_F_OVERRIDE|
1074 NEIGH_UPDATE_F_ADMIN);
1075 neigh_release(neigh);
1076 }
1077
1078 return err;
1079}
1080
1081static int arp_req_delete_public(struct net *net, struct arpreq *r,
1082 struct net_device *dev)
1083{
1084 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1085 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1086
1087 if (mask == htonl(0xFFFFFFFF))
1088 return pneigh_delete(&arp_tbl, net, &ip, dev);
1089
1090 if (mask)
1091 return -EINVAL;
1092
1093 return arp_req_set_proxy(net, dev, 0);
1094}
1095
1096static int arp_req_delete(struct net *net, struct arpreq *r,
1097 struct net_device *dev)
1098{
1099 __be32 ip;
1100
1101 if (r->arp_flags & ATF_PUBL)
1102 return arp_req_delete_public(net, r, dev);
1103
1104 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1105 if (!dev) {
1106 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1107 if (IS_ERR(rt))
1108 return PTR_ERR(rt);
1109 dev = rt->dst.dev;
1110 ip_rt_put(rt);
1111 if (!dev)
1112 return -EINVAL;
1113 }
1114 return arp_invalidate(dev, ip);
1115}
1116
1117
1118
1119
1120
1121int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1122{
1123 int err;
1124 struct arpreq r;
1125 struct net_device *dev = NULL;
1126
1127 switch (cmd) {
1128 case SIOCDARP:
1129 case SIOCSARP:
1130 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1131 return -EPERM;
1132 case SIOCGARP:
1133 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1134 if (err)
1135 return -EFAULT;
1136 break;
1137 default:
1138 return -EINVAL;
1139 }
1140
1141 if (r.arp_pa.sa_family != AF_INET)
1142 return -EPFNOSUPPORT;
1143
1144 if (!(r.arp_flags & ATF_PUBL) &&
1145 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1146 return -EINVAL;
1147 if (!(r.arp_flags & ATF_NETMASK))
1148 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1149 htonl(0xFFFFFFFFUL);
1150 rtnl_lock();
1151 if (r.arp_dev[0]) {
1152 err = -ENODEV;
1153 dev = __dev_get_by_name(net, r.arp_dev);
1154 if (!dev)
1155 goto out;
1156
1157
1158 if (!r.arp_ha.sa_family)
1159 r.arp_ha.sa_family = dev->type;
1160 err = -EINVAL;
1161 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1162 goto out;
1163 } else if (cmd == SIOCGARP) {
1164 err = -ENODEV;
1165 goto out;
1166 }
1167
1168 switch (cmd) {
1169 case SIOCDARP:
1170 err = arp_req_delete(net, &r, dev);
1171 break;
1172 case SIOCSARP:
1173 err = arp_req_set(net, &r, dev);
1174 break;
1175 case SIOCGARP:
1176 err = arp_req_get(&r, dev);
1177 break;
1178 }
1179out:
1180 rtnl_unlock();
1181 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1182 err = -EFAULT;
1183 return err;
1184}
1185
1186static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1187 void *ptr)
1188{
1189 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1190 struct netdev_notifier_change_info *change_info;
1191
1192 switch (event) {
1193 case NETDEV_CHANGEADDR:
1194 neigh_changeaddr(&arp_tbl, dev);
1195 rt_cache_flush(dev_net(dev));
1196 break;
1197 case NETDEV_CHANGE:
1198 change_info = ptr;
1199 if (change_info->flags_changed & IFF_NOARP)
1200 neigh_changeaddr(&arp_tbl, dev);
1201 break;
1202 default:
1203 break;
1204 }
1205
1206 return NOTIFY_DONE;
1207}
1208
1209static struct notifier_block arp_netdev_notifier = {
1210 .notifier_call = arp_netdev_event,
1211};
1212
1213
1214
1215
1216
1217void arp_ifdown(struct net_device *dev)
1218{
1219 neigh_ifdown(&arp_tbl, dev);
1220}
1221
1222
1223
1224
1225
1226
1227static struct packet_type arp_packet_type __read_mostly = {
1228 .type = cpu_to_be16(ETH_P_ARP),
1229 .func = arp_rcv,
1230};
1231
1232static int arp_proc_init(void);
1233
1234void __init arp_init(void)
1235{
1236 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
1237
1238 dev_add_pack(&arp_packet_type);
1239 arp_proc_init();
1240#ifdef CONFIG_SYSCTL
1241 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1242#endif
1243 register_netdevice_notifier(&arp_netdev_notifier);
1244}
1245
1246#ifdef CONFIG_PROC_FS
1247#if IS_ENABLED(CONFIG_AX25)
1248
1249
1250
1251
1252
1253static char *ax2asc2(ax25_address *a, char *buf)
1254{
1255 char c, *s;
1256 int n;
1257
1258 for (n = 0, s = buf; n < 6; n++) {
1259 c = (a->ax25_call[n] >> 1) & 0x7F;
1260
1261 if (c != ' ')
1262 *s++ = c;
1263 }
1264
1265 *s++ = '-';
1266 n = (a->ax25_call[6] >> 1) & 0x0F;
1267 if (n > 9) {
1268 *s++ = '1';
1269 n -= 10;
1270 }
1271
1272 *s++ = n + '0';
1273 *s++ = '\0';
1274
1275 if (*buf == '\0' || *buf == '-')
1276 return "*";
1277
1278 return buf;
1279}
1280#endif
1281
1282#define HBUFFERLEN 30
1283
1284static void arp_format_neigh_entry(struct seq_file *seq,
1285 struct neighbour *n)
1286{
1287 char hbuffer[HBUFFERLEN];
1288 int k, j;
1289 char tbuf[16];
1290 struct net_device *dev = n->dev;
1291 int hatype = dev->type;
1292
1293 read_lock(&n->lock);
1294
1295#if IS_ENABLED(CONFIG_AX25)
1296 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1297 ax2asc2((ax25_address *)n->ha, hbuffer);
1298 else {
1299#endif
1300 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1301 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1302 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1303 hbuffer[k++] = ':';
1304 }
1305 if (k != 0)
1306 --k;
1307 hbuffer[k] = 0;
1308#if IS_ENABLED(CONFIG_AX25)
1309 }
1310#endif
1311 sprintf(tbuf, "%pI4", n->primary_key);
1312 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1313 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1314 read_unlock(&n->lock);
1315}
1316
1317static void arp_format_pneigh_entry(struct seq_file *seq,
1318 struct pneigh_entry *n)
1319{
1320 struct net_device *dev = n->dev;
1321 int hatype = dev ? dev->type : 0;
1322 char tbuf[16];
1323
1324 sprintf(tbuf, "%pI4", n->key);
1325 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1326 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1327 dev ? dev->name : "*");
1328}
1329
1330static int arp_seq_show(struct seq_file *seq, void *v)
1331{
1332 if (v == SEQ_START_TOKEN) {
1333 seq_puts(seq, "IP address HW type Flags "
1334 "HW address Mask Device\n");
1335 } else {
1336 struct neigh_seq_state *state = seq->private;
1337
1338 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1339 arp_format_pneigh_entry(seq, v);
1340 else
1341 arp_format_neigh_entry(seq, v);
1342 }
1343
1344 return 0;
1345}
1346
1347static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1348{
1349
1350
1351
1352 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1353}
1354
1355
1356
1357static const struct seq_operations arp_seq_ops = {
1358 .start = arp_seq_start,
1359 .next = neigh_seq_next,
1360 .stop = neigh_seq_stop,
1361 .show = arp_seq_show,
1362};
1363
1364static int arp_seq_open(struct inode *inode, struct file *file)
1365{
1366 return seq_open_net(inode, file, &arp_seq_ops,
1367 sizeof(struct neigh_seq_state));
1368}
1369
1370static const struct file_operations arp_seq_fops = {
1371 .owner = THIS_MODULE,
1372 .open = arp_seq_open,
1373 .read = seq_read,
1374 .llseek = seq_lseek,
1375 .release = seq_release_net,
1376};
1377
1378
1379static int __net_init arp_net_init(struct net *net)
1380{
1381 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops))
1382 return -ENOMEM;
1383 return 0;
1384}
1385
1386static void __net_exit arp_net_exit(struct net *net)
1387{
1388 remove_proc_entry("arp", net->proc_net);
1389}
1390
1391static struct pernet_operations arp_net_ops = {
1392 .init = arp_net_init,
1393 .exit = arp_net_exit,
1394};
1395
1396static int __init arp_proc_init(void)
1397{
1398 return register_pernet_subsys(&arp_net_ops);
1399}
1400
1401#else
1402
1403static int __init arp_proc_init(void)
1404{
1405 return 0;
1406}
1407
1408#endif
1409