1 /* linux/net/inet/arp.c
2 *
3 * Version: $Id: arp.c,v 1.99 2001/08/30 22:55:42 davem Exp $
4 *
5 * Copyright (C) 1994 by Florian La Roche
6 *
7 * This module implements the Address Resolution Protocol ARP (RFC 826),
8 * which is used to convert IP addresses (or in the future maybe other
9 * high-level addresses) into a low-level hardware address (like an Ethernet
10 * address).
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * Fixes:
18 * Alan Cox : Removed the Ethernet assumptions in
19 * Florian's code
20 * Alan Cox : Fixed some small errors in the ARP
21 * logic
22 * Alan Cox : Allow >4K in /proc
23 * Alan Cox : Make ARP add its own protocol entry
24 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
25 * Stephen Henson : Add AX25 support to arp_get_info()
26 * Alan Cox : Drop data when a device is downed.
27 * Alan Cox : Use init_timer().
28 * Alan Cox : Double lock fixes.
29 * Martin Seine : Move the arphdr structure
30 * to if_arp.h for compatibility.
31 * with BSD based programs.
32 * Andrew Tridgell : Added ARP netmask code and
33 * re-arranged proxy handling.
34 * Alan Cox : Changed to use notifiers.
35 * Niibe Yutaka : Reply for this device or proxies only.
36 * Alan Cox : Don't proxy across hardware types!
37 * Jonathan Naylor : Added support for NET/ROM.
38 * Mike Shaver : RFC1122 checks.
39 * Jonathan Naylor : Only lookup the hardware address for
40 * the correct hardware type.
41 * Germano Caronni : Assorted subtle races.
42 * Craig Schlenter : Don't modify permanent entry
43 * during arp_rcv.
44 * Russ Nelson : Tidied up a few bits.
45 * Alexey Kuznetsov: Major changes to caching and behaviour,
46 * eg intelligent arp probing and
47 * generation
48 * of host down events.
49 * Alan Cox : Missing unlock in device events.
50 * Eckes : ARP ioctl control errors.
51 * Alexey Kuznetsov: Arp free fix.
52 * Manuel Rodriguez: Gratuitous ARP.
53 * Jonathan Layes : Added arpd support through kerneld
54 * message queue (960314)
55 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
56 * Mike McLagan : Routing by source
57 * Stuart Cheshire : Metricom and grat arp fixes
58 * *** FOR 2.1 clean this up ***
59 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
60 * Alan Cox : Took the AP1000 nasty FDDI hack and
61 * folded into the mainstream FDDI code.
62 * Ack spit, Linus how did you allow that
63 * one in...
64 * Jes Sorensen : Make FDDI work again in 2.1.x and
65 * clean up the APFDDI & gen. FDDI bits.
66 * Alexey Kuznetsov: new arp state machine;
67 * now it is in net/core/neighbour.c.
68 * Krzysztof Halasa: Added Frame Relay ARP support.
69 * Shmulik Hen: Split arp_send to arp_create and
70 * arp_xmit so intermediate drivers like
71 * bonding can change the skb before
72 * sending (e.g. insert 8021q tag).
73 * Harald Welte : convert to make use of jenkins hash
74 */
75
76 #include <linux/types.h>
77 #include <linux/string.h>
78 #include <linux/kernel.h>
79 #include <linux/module.h>
80 #include <linux/sched.h>
81 #include <linux/config.h>
82 #include <linux/socket.h>
83 #include <linux/sockios.h>
84 #include <linux/errno.h>
85 #include <linux/in.h>
86 #include <linux/mm.h>
87 #include <linux/inet.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/stat.h>
96 #include <linux/init.h>
97 #include <linux/jhash.h>
98 #include <linux/module.h>
99 #ifdef CONFIG_SYSCTL
100 #include <linux/sysctl.h>
101 #endif
102
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 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
111 #include <net/ax25.h>
112 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
113 #include <net/netrom.h>
114 #endif
115 #endif
116 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
117 #include <net/atmclip.h>
118 struct neigh_table *clip_tbl_hook;
119 #endif
120
121 #include <asm/system.h>
122 #include <asm/uaccess.h>
123
124 #include <linux/netfilter_arp.h>
125
126 /*
127 * Interface to generic neighbour cache.
128 */
129 static u32 arp_hash(const void *pkey, const struct net_device *dev);
130 static int arp_constructor(struct neighbour *neigh);
131 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
132 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
133 static void parp_redo(struct sk_buff *skb);
134
135 static 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 hh_output: dev_queue_xmit,
142 queue_xmit: dev_queue_xmit,
143 };
144
145 static struct neigh_ops arp_hh_ops = {
146 family: AF_INET,
147 solicit: arp_solicit,
148 error_report: arp_error_report,
149 output: neigh_resolve_output,
150 connected_output: neigh_resolve_output,
151 hh_output: dev_queue_xmit,
152 queue_xmit: dev_queue_xmit,
153 };
154
155 static struct neigh_ops arp_direct_ops = {
156 family: AF_INET,
157 output: dev_queue_xmit,
158 connected_output: dev_queue_xmit,
159 hh_output: dev_queue_xmit,
160 queue_xmit: dev_queue_xmit,
161 };
162
163 struct neigh_ops arp_broken_ops = {
164 family: AF_INET,
165 solicit: arp_solicit,
166 error_report: arp_error_report,
167 output: neigh_compat_output,
168 connected_output: neigh_compat_output,
169 hh_output: dev_queue_xmit,
170 queue_xmit: dev_queue_xmit,
171 };
172
173 struct neigh_table arp_tbl = {
174 family: AF_INET,
175 entry_size: sizeof(struct neighbour) + 4,
176 key_len: 4,
177 hash: arp_hash,
178 constructor: arp_constructor,
179 proxy_redo: parp_redo,
180 id: "arp_cache",
181 parms: {
182 tbl: &arp_tbl,
183 base_reachable_time: 30 * HZ,
184 retrans_time: 1 * HZ,
185 gc_staletime: 60 * HZ,
186 reachable_time: 30 * HZ,
187 delay_probe_time: 5 * HZ,
188 queue_len: 3,
189 ucast_probes: 3,
190 mcast_probes: 3,
191 anycast_delay: 1 * HZ,
192 proxy_delay: (8 * HZ) / 10,
193 proxy_qlen: 64,
194 locktime: 1 * HZ,
195 },
196 gc_interval: 30 * HZ,
197 gc_thresh1: 128,
198 gc_thresh2: 512,
199 gc_thresh3: 1024,
200 };
201
arp_mc_map(u32 addr,u8 * haddr,struct net_device * dev,int dir)202 int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir)
203 {
204 switch (dev->type) {
205 case ARPHRD_ETHER:
206 case ARPHRD_FDDI:
207 case ARPHRD_IEEE802:
208 ip_eth_mc_map(addr, haddr);
209 return 0;
210 case ARPHRD_IEEE802_TR:
211 ip_tr_mc_map(addr, haddr);
212 return 0;
213 default:
214 if (dir) {
215 memcpy(haddr, dev->broadcast, dev->addr_len);
216 return 0;
217 }
218 }
219 return -EINVAL;
220 }
221
222
arp_hash(const void * pkey,const struct net_device * dev)223 static u32 arp_hash(const void *pkey, const struct net_device *dev)
224 {
225 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd);
226 }
227
arp_constructor(struct neighbour * neigh)228 static int arp_constructor(struct neighbour *neigh)
229 {
230 u32 addr = *(u32*)neigh->primary_key;
231 struct net_device *dev = neigh->dev;
232 struct in_device *in_dev = in_dev_get(dev);
233
234 if (in_dev == NULL)
235 return -EINVAL;
236
237 neigh->type = inet_addr_type(addr);
238 if (in_dev->arp_parms)
239 neigh->parms = in_dev->arp_parms;
240
241 in_dev_put(in_dev);
242
243 if (dev->hard_header == NULL) {
244 neigh->nud_state = NUD_NOARP;
245 neigh->ops = &arp_direct_ops;
246 neigh->output = neigh->ops->queue_xmit;
247 } else {
248 /* Good devices (checked by reading texts, but only Ethernet is
249 tested)
250
251 ARPHRD_ETHER: (ethernet, apfddi)
252 ARPHRD_FDDI: (fddi)
253 ARPHRD_IEEE802: (tr)
254 ARPHRD_METRICOM: (strip)
255 ARPHRD_ARCNET:
256 etc. etc. etc.
257
258 ARPHRD_IPDDP will also work, if author repairs it.
259 I did not it, because this driver does not work even
260 in old paradigm.
261 */
262
263 #if 1
264 /* So... these "amateur" devices are hopeless.
265 The only thing, that I can say now:
266 It is very sad that we need to keep ugly obsolete
267 code to make them happy.
268
269 They should be moved to more reasonable state, now
270 they use rebuild_header INSTEAD OF hard_start_xmit!!!
271 Besides that, they are sort of out of date
272 (a lot of redundant clones/copies, useless in 2.1),
273 I wonder why people believe that they work.
274 */
275 switch (dev->type) {
276 default:
277 break;
278 case ARPHRD_ROSE:
279 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
280 case ARPHRD_AX25:
281 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
282 case ARPHRD_NETROM:
283 #endif
284 neigh->ops = &arp_broken_ops;
285 neigh->output = neigh->ops->output;
286 return 0;
287 #endif
288 ;}
289 #endif
290 if (neigh->type == RTN_MULTICAST) {
291 neigh->nud_state = NUD_NOARP;
292 arp_mc_map(addr, neigh->ha, dev, 1);
293 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
294 neigh->nud_state = NUD_NOARP;
295 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
296 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) {
297 neigh->nud_state = NUD_NOARP;
298 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
299 }
300 if (dev->hard_header_cache)
301 neigh->ops = &arp_hh_ops;
302 else
303 neigh->ops = &arp_generic_ops;
304 if (neigh->nud_state&NUD_VALID)
305 neigh->output = neigh->ops->connected_output;
306 else
307 neigh->output = neigh->ops->output;
308 }
309 return 0;
310 }
311
arp_error_report(struct neighbour * neigh,struct sk_buff * skb)312 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
313 {
314 dst_link_failure(skb);
315 kfree_skb(skb);
316 }
317
arp_solicit(struct neighbour * neigh,struct sk_buff * skb)318 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
319 {
320 u32 saddr = 0;
321 u8 *dst_ha = NULL;
322 struct net_device *dev = neigh->dev;
323 u32 target = *(u32*)neigh->primary_key;
324 int probes = atomic_read(&neigh->probes);
325 struct in_device *in_dev = in_dev_get(dev);
326
327 if (!in_dev)
328 return;
329
330 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
331 default:
332 case 0: /* By default announce any local IP */
333 if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL)
334 saddr = skb->nh.iph->saddr;
335 break;
336 case 1: /* Restrict announcements of saddr in same subnet */
337 if (!skb)
338 break;
339 saddr = skb->nh.iph->saddr;
340 if (inet_addr_type(saddr) == RTN_LOCAL) {
341 /* saddr should be known to target */
342 if (inet_addr_onlink(in_dev, target, saddr))
343 break;
344 }
345 saddr = 0;
346 break;
347 case 2: /* Avoid secondary IPs, get a primary/preferred one */
348 break;
349 }
350
351 if (in_dev)
352 in_dev_put(in_dev);
353 if (!saddr)
354 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
355
356 if ((probes -= neigh->parms->ucast_probes) < 0) {
357 if (!(neigh->nud_state&NUD_VALID))
358 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n");
359 dst_ha = neigh->ha;
360 read_lock_bh(&neigh->lock);
361 } else if ((probes -= neigh->parms->app_probes) < 0) {
362 #ifdef CONFIG_ARPD
363 neigh_app_ns(neigh);
364 #endif
365 return;
366 }
367
368 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
369 dst_ha, dev->dev_addr, NULL);
370 if (dst_ha)
371 read_unlock_bh(&neigh->lock);
372 }
373
arp_ignore(struct in_device * in_dev,struct net_device * dev,u32 sip,u32 tip)374 static int arp_ignore(struct in_device *in_dev, struct net_device *dev,
375 u32 sip, u32 tip)
376 {
377 int scope;
378
379 switch (IN_DEV_ARP_IGNORE(in_dev)) {
380 case 0: /* Reply, the tip is already validated */
381 return 0;
382 case 1: /* Reply only if tip is configured on the incoming interface */
383 sip = 0;
384 scope = RT_SCOPE_HOST;
385 break;
386 case 2: /*
387 * Reply only if tip is configured on the incoming interface
388 * and is in same subnet as sip
389 */
390 scope = RT_SCOPE_HOST;
391 break;
392 case 3: /* Do not reply for scope host addresses */
393 sip = 0;
394 scope = RT_SCOPE_LINK;
395 dev = NULL;
396 break;
397 case 4: /* Reserved */
398 case 5:
399 case 6:
400 case 7:
401 return 0;
402 case 8: /* Do not reply */
403 return 1;
404 default:
405 return 0;
406 }
407 return !inet_confirm_addr(dev, sip, tip, scope);
408 }
409
arp_filter(__u32 sip,__u32 tip,struct net_device * dev)410 static int arp_filter(__u32 sip, __u32 tip, struct net_device *dev)
411 {
412 struct rtable *rt;
413 int flag = 0;
414 /*unsigned long now; */
415
416 if (ip_route_output(&rt, sip, tip, 0, 0) < 0)
417 return 1;
418 if (rt->u.dst.dev != dev) {
419 NET_INC_STATS_BH(ArpFilter);
420 flag = 1;
421 }
422 ip_rt_put(rt);
423 return flag;
424 }
425
426 /* OBSOLETE FUNCTIONS */
427
428 /*
429 * Find an arp mapping in the cache. If not found, post a request.
430 *
431 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
432 * even if it exists. It is supposed that skb->dev was mangled
433 * by a virtual device (eql, shaper). Nobody but broken devices
434 * is allowed to use this function, it is scheduled to be removed. --ANK
435 */
436
arp_set_predefined(int addr_hint,unsigned char * haddr,u32 paddr,struct net_device * dev)437 static int arp_set_predefined(int addr_hint, unsigned char * haddr, u32 paddr, struct net_device * dev)
438 {
439 switch (addr_hint) {
440 case RTN_LOCAL:
441 printk(KERN_DEBUG "ARP: arp called for own IP address\n");
442 memcpy(haddr, dev->dev_addr, dev->addr_len);
443 return 1;
444 case RTN_MULTICAST:
445 arp_mc_map(paddr, haddr, dev, 1);
446 return 1;
447 case RTN_BROADCAST:
448 memcpy(haddr, dev->broadcast, dev->addr_len);
449 return 1;
450 }
451 return 0;
452 }
453
454
arp_find(unsigned char * haddr,struct sk_buff * skb)455 int arp_find(unsigned char *haddr, struct sk_buff *skb)
456 {
457 struct net_device *dev = skb->dev;
458 u32 paddr;
459 struct neighbour *n;
460
461 if (!skb->dst) {
462 printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
463 kfree_skb(skb);
464 return 1;
465 }
466
467 paddr = ((struct rtable*)skb->dst)->rt_gateway;
468
469 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev))
470 return 0;
471
472 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
473
474 if (n) {
475 n->used = jiffies;
476 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) {
477 read_lock_bh(&n->lock);
478 memcpy(haddr, n->ha, dev->addr_len);
479 read_unlock_bh(&n->lock);
480 neigh_release(n);
481 return 0;
482 }
483 neigh_release(n);
484 } else
485 kfree_skb(skb);
486 return 1;
487 }
488
489 /* END OF OBSOLETE FUNCTIONS */
490
arp_bind_neighbour(struct dst_entry * dst)491 int arp_bind_neighbour(struct dst_entry *dst)
492 {
493 struct net_device *dev = dst->dev;
494 struct neighbour *n = dst->neighbour;
495
496 if (dev == NULL)
497 return -EINVAL;
498 if (n == NULL) {
499 u32 nexthop = ((struct rtable*)dst)->rt_gateway;
500 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT))
501 nexthop = 0;
502 n = __neigh_lookup_errno(
503 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
504 dev->type == ARPHRD_ATM ? clip_tbl_hook :
505 #endif
506 &arp_tbl, &nexthop, dev);
507 if (IS_ERR(n))
508 return PTR_ERR(n);
509 dst->neighbour = n;
510 }
511 return 0;
512 }
513
514 /*
515 * Check if we can use proxy ARP for this path
516 */
517
arp_fwd_proxy(struct in_device * in_dev,struct rtable * rt)518 static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
519 {
520 struct in_device *out_dev;
521 int imi, omi = -1;
522
523 if (!IN_DEV_PROXY_ARP(in_dev))
524 return 0;
525
526 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0)
527 return 1;
528 if (imi == -1)
529 return 0;
530
531 /* place to check for proxy_arp for routes */
532
533 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) {
534 omi = IN_DEV_MEDIUM_ID(out_dev);
535 in_dev_put(out_dev);
536 }
537 return (omi != imi && omi != -1);
538 }
539
540 /*
541 * Interface to link layer: send routine and receive handler.
542 */
543
544 /*
545 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
546 * message.
547 */
arp_create(int type,int ptype,u32 dest_ip,struct net_device * dev,u32 src_ip,unsigned char * dest_hw,unsigned char * src_hw,unsigned char * target_hw)548 struct sk_buff *arp_create(int type, int ptype, u32 dest_ip,
549 struct net_device *dev, u32 src_ip,
550 unsigned char *dest_hw, unsigned char *src_hw,
551 unsigned char *target_hw)
552 {
553 struct sk_buff *skb;
554 struct arphdr *arp;
555 unsigned char *arp_ptr;
556
557 /*
558 * Allocate a buffer
559 */
560
561 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4)
562 + dev->hard_header_len + 15, GFP_ATOMIC);
563 if (skb == NULL)
564 return NULL;
565
566 skb_reserve(skb, (dev->hard_header_len+15)&~15);
567 skb->nh.raw = skb->data;
568 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4));
569 skb->dev = dev;
570 skb->protocol = htons (ETH_P_ARP);
571 if (src_hw == NULL)
572 src_hw = dev->dev_addr;
573 if (dest_hw == NULL)
574 dest_hw = dev->broadcast;
575
576 /*
577 * Fill the device header for the ARP frame
578 */
579 if (dev->hard_header &&
580 dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0)
581 goto out;
582
583 /*
584 * Fill out the arp protocol part.
585 *
586 * The arp hardware type should match the device type, except for FDDI,
587 * which (according to RFC 1390) should always equal 1 (Ethernet).
588 */
589 /*
590 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
591 * DIX code for the protocol. Make these device structure fields.
592 */
593 switch (dev->type) {
594 default:
595 arp->ar_hrd = htons(dev->type);
596 arp->ar_pro = htons(ETH_P_IP);
597 break;
598
599 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
600 case ARPHRD_AX25:
601 arp->ar_hrd = htons(ARPHRD_AX25);
602 arp->ar_pro = htons(AX25_P_IP);
603 break;
604
605 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
606 case ARPHRD_NETROM:
607 arp->ar_hrd = htons(ARPHRD_NETROM);
608 arp->ar_pro = htons(AX25_P_IP);
609 break;
610 #endif
611 #endif
612
613 #ifdef CONFIG_FDDI
614 case ARPHRD_FDDI:
615 arp->ar_hrd = htons(ARPHRD_ETHER);
616 arp->ar_pro = htons(ETH_P_IP);
617 break;
618 #endif
619 #ifdef CONFIG_TR
620 case ARPHRD_IEEE802_TR:
621 arp->ar_hrd = htons(ARPHRD_IEEE802);
622 arp->ar_pro = htons(ETH_P_IP);
623 break;
624 #endif
625 }
626
627 arp->ar_hln = dev->addr_len;
628 arp->ar_pln = 4;
629 arp->ar_op = htons(type);
630
631 arp_ptr=(unsigned char *)(arp+1);
632
633 memcpy(arp_ptr, src_hw, dev->addr_len);
634 arp_ptr+=dev->addr_len;
635 memcpy(arp_ptr, &src_ip,4);
636 arp_ptr+=4;
637 if (target_hw != NULL)
638 memcpy(arp_ptr, target_hw, dev->addr_len);
639 else
640 memset(arp_ptr, 0, dev->addr_len);
641 arp_ptr+=dev->addr_len;
642 memcpy(arp_ptr, &dest_ip, 4);
643
644 return skb;
645
646 out:
647 kfree_skb(skb);
648 return NULL;
649 }
650
651 /*
652 * Send an arp packet.
653 */
arp_xmit(struct sk_buff * skb)654 void arp_xmit(struct sk_buff *skb)
655 {
656 /* Send it off, maybe filter it using firewalling first. */
657 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
658 }
659
660 /*
661 * Create and send an arp packet.
662 */
arp_send(int type,int ptype,u32 dest_ip,struct net_device * dev,u32 src_ip,unsigned char * dest_hw,unsigned char * src_hw,unsigned char * target_hw)663 void arp_send(int type, int ptype, u32 dest_ip,
664 struct net_device *dev, u32 src_ip,
665 unsigned char *dest_hw, unsigned char *src_hw,
666 unsigned char *target_hw)
667 {
668 struct sk_buff *skb;
669
670 /*
671 * No arp on this interface.
672 */
673
674 if (dev->flags&IFF_NOARP)
675 return;
676
677 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
678 dest_hw, src_hw, target_hw);
679 if (skb == NULL) {
680 return;
681 }
682
683 arp_xmit(skb);
684 }
685
parp_redo(struct sk_buff * skb)686 static void parp_redo(struct sk_buff *skb)
687 {
688 arp_rcv(skb, skb->dev, NULL);
689 }
690
691 /*
692 * Process an arp request.
693 */
694
arp_process(struct sk_buff * skb)695 int arp_process(struct sk_buff *skb)
696 {
697 struct net_device *dev = skb->dev;
698 struct in_device *in_dev = in_dev_get(dev);
699 struct arphdr *arp;
700 unsigned char *arp_ptr;
701 struct rtable *rt;
702 unsigned char *sha, *tha;
703 u32 sip, tip;
704 u16 dev_type = dev->type;
705 int addr_type;
706 struct neighbour *n;
707
708 /* arp_rcv below verifies the ARP header, verifies the device
709 * is ARP'able, and linearizes the SKB (if needed).
710 */
711
712 if (in_dev == NULL)
713 goto out;
714
715 arp = skb->nh.arph;
716 arp_ptr= (unsigned char *)(arp+1);
717
718 switch (dev_type) {
719 default:
720 if (arp->ar_pro != htons(ETH_P_IP))
721 goto out;
722 if (htons(dev_type) != arp->ar_hrd)
723 goto out;
724 break;
725 #ifdef CONFIG_NET_ETHERNET
726 case ARPHRD_ETHER:
727 /*
728 * ETHERNET devices will accept ARP hardware types of either
729 * 1 (Ethernet) or 6 (IEEE 802.2).
730 */
731 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
732 arp->ar_hrd != htons(ARPHRD_IEEE802))
733 goto out;
734 if (arp->ar_pro != htons(ETH_P_IP))
735 goto out;
736 break;
737 #endif
738 #ifdef CONFIG_TR
739 case ARPHRD_IEEE802_TR:
740 /*
741 * Token ring devices will accept ARP hardware types of either
742 * 1 (Ethernet) or 6 (IEEE 802.2).
743 */
744 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
745 arp->ar_hrd != htons(ARPHRD_IEEE802))
746 goto out;
747 if (arp->ar_pro != htons(ETH_P_IP))
748 goto out;
749 break;
750 #endif
751 #ifdef CONFIG_FDDI
752 case ARPHRD_FDDI:
753 /*
754 * According to RFC 1390, FDDI devices should accept ARP hardware types
755 * of 1 (Ethernet). However, to be more robust, we'll accept hardware
756 * types of either 1 (Ethernet) or 6 (IEEE 802.2).
757 */
758 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
759 arp->ar_hrd != htons(ARPHRD_IEEE802))
760 goto out;
761 if (arp->ar_pro != htons(ETH_P_IP))
762 goto out;
763 break;
764 #endif
765 #ifdef CONFIG_NET_FC
766 case ARPHRD_IEEE802:
767 /*
768 * According to RFC 2625, Fibre Channel devices (which are IEEE
769 * 802 devices) should accept ARP hardware types of 6 (IEEE 802)
770 * and 1 (Ethernet).
771 */
772 if (arp->ar_hrd != htons(ARPHRD_ETHER) &&
773 arp->ar_hrd != htons(ARPHRD_IEEE802))
774 goto out;
775 if (arp->ar_pro != htons(ETH_P_IP))
776 goto out;
777 break;
778 #endif
779 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
780 case ARPHRD_AX25:
781 if (arp->ar_pro != htons(AX25_P_IP))
782 goto out;
783 if (arp->ar_hrd != htons(ARPHRD_AX25))
784 goto out;
785 break;
786 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
787 case ARPHRD_NETROM:
788 if (arp->ar_pro != htons(AX25_P_IP))
789 goto out;
790 if (arp->ar_hrd != htons(ARPHRD_NETROM))
791 goto out;
792 break;
793 #endif
794 #endif
795 }
796
797 /* Understand only these message types */
798
799 if (arp->ar_op != htons(ARPOP_REPLY) &&
800 arp->ar_op != htons(ARPOP_REQUEST))
801 goto out;
802
803 /*
804 * Extract fields
805 */
806 sha=arp_ptr;
807 arp_ptr += dev->addr_len;
808 memcpy(&sip, arp_ptr, 4);
809 arp_ptr += 4;
810 tha=arp_ptr;
811 arp_ptr += dev->addr_len;
812 memcpy(&tip, arp_ptr, 4);
813 /*
814 * Check for bad requests for 127.x.x.x and requests for multicast
815 * addresses. If this is one such, delete it.
816 */
817 if (LOOPBACK(tip) || MULTICAST(tip))
818 goto out;
819
820 /*
821 * Special case: We must set Frame Relay source Q.922 address
822 */
823 if (dev_type == ARPHRD_DLCI)
824 sha = dev->broadcast;
825
826 /*
827 * Process entry. The idea here is we want to send a reply if it is a
828 * request for us or if it is a request for someone else that we hold
829 * a proxy for. We want to add an entry to our cache if it is a reply
830 * to us or if it is a request for our address.
831 * (The assumption for this last is that if someone is requesting our
832 * address, they are probably intending to talk to us, so it saves time
833 * if we cache their address. Their address is also probably not in
834 * our cache, since ours is not in their cache.)
835 *
836 * Putting this another way, we only care about replies if they are to
837 * us, in which case we add them to the cache. For requests, we care
838 * about those for us and those for our proxies. We reply to both,
839 * and in the case of requests for us we add the requester to the arp
840 * cache.
841 */
842
843 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
844 if (sip == 0) {
845 if (arp->ar_op == htons(ARPOP_REQUEST) &&
846 inet_addr_type(tip) == RTN_LOCAL &&
847 !arp_ignore(in_dev,dev,sip,tip))
848 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
849 dev->dev_addr, sha);
850 goto out;
851 }
852
853 if (arp->ar_op == htons(ARPOP_REQUEST) &&
854 ip_route_input(skb, tip, sip, 0, dev) == 0) {
855
856 rt = (struct rtable*)skb->dst;
857 addr_type = rt->rt_type;
858
859 if (addr_type == RTN_LOCAL) {
860 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
861 if (n) {
862 int dont_send = 0;
863
864 if (!dont_send)
865 dont_send |= arp_ignore(in_dev,dev,sip,tip);
866 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
867 dont_send |= arp_filter(sip,tip,dev);
868 if (!dont_send)
869 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
870
871 neigh_release(n);
872 }
873 goto out;
874 } else if (IN_DEV_FORWARD(in_dev)) {
875 if ((rt->rt_flags&RTCF_DNAT) ||
876 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev &&
877 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) {
878 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
879 if (n)
880 neigh_release(n);
881
882 if (skb->stamp.tv_sec == 0 ||
883 skb->pkt_type == PACKET_HOST ||
884 in_dev->arp_parms->proxy_delay == 0) {
885 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
886 } else {
887 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb);
888 in_dev_put(in_dev);
889 return 0;
890 }
891 goto out;
892 }
893 }
894 }
895
896 /* Update our ARP tables */
897
898 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
899
900 #ifdef CONFIG_IP_ACCEPT_UNSOLICITED_ARP
901 /* Unsolicited ARP is not accepted by default.
902 It is possible, that this option should be enabled for some
903 devices (strip is candidate)
904 */
905 if (n == NULL &&
906 arp->ar_op == htons(ARPOP_REPLY) &&
907 inet_addr_type(sip) == RTN_UNICAST)
908 n = __neigh_lookup(&arp_tbl, &sip, dev, -1);
909 #endif
910
911 if (n) {
912 int state = NUD_REACHABLE;
913 int override = 0;
914
915 /* If several different ARP replies follows back-to-back,
916 use the FIRST one. It is possible, if several proxy
917 agents are active. Taking the first reply prevents
918 arp trashing and chooses the fastest router.
919 */
920 if (jiffies - n->updated >= n->parms->locktime)
921 override = 1;
922
923 /* Broadcast replies and request packets
924 do not assert neighbour reachability.
925 */
926 if (arp->ar_op != htons(ARPOP_REPLY) ||
927 skb->pkt_type != PACKET_HOST)
928 state = NUD_STALE;
929 neigh_update(n, sha, state, override, 1);
930 neigh_release(n);
931 }
932
933 out:
934 if (in_dev)
935 in_dev_put(in_dev);
936 kfree_skb(skb);
937 return 0;
938 }
939
940
941 /*
942 * Receive an arp request from the device layer.
943 */
944
arp_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt)945 int arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
946 {
947 struct arphdr *arp;
948
949 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
950 if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
951 (2 * dev->addr_len) +
952 (2 * sizeof(u32)))))
953 goto freeskb;
954
955 arp = skb->nh.arph;
956 if (arp->ar_hln != dev->addr_len ||
957 dev->flags & IFF_NOARP ||
958 skb->pkt_type == PACKET_OTHERHOST ||
959 skb->pkt_type == PACKET_LOOPBACK ||
960 arp->ar_pln != 4)
961 goto freeskb;
962
963 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
964 goto out_of_mem;
965
966 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
967
968 freeskb:
969 kfree_skb(skb);
970 out_of_mem:
971 return 0;
972 }
973
974 /*
975 * User level interface (ioctl, /proc)
976 */
977
978 /*
979 * Set (create) an ARP cache entry.
980 */
981
arp_req_set(struct arpreq * r,struct net_device * dev)982 int arp_req_set(struct arpreq *r, struct net_device * dev)
983 {
984 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
985 struct neighbour *neigh;
986 int err;
987
988 if (r->arp_flags&ATF_PUBL) {
989 u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
990 if (mask && mask != 0xFFFFFFFF)
991 return -EINVAL;
992 if (!dev && (r->arp_flags & ATF_COM)) {
993 dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data);
994 if (!dev)
995 return -ENODEV;
996 }
997 if (mask) {
998 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL)
999 return -ENOBUFS;
1000 return 0;
1001 }
1002 if (dev == NULL) {
1003 ipv4_devconf.proxy_arp = 1;
1004 return 0;
1005 }
1006 if (__in_dev_get(dev)) {
1007 __in_dev_get(dev)->cnf.proxy_arp = 1;
1008 return 0;
1009 }
1010 return -ENXIO;
1011 }
1012
1013 if (r->arp_flags & ATF_PERM)
1014 r->arp_flags |= ATF_COM;
1015 if (dev == NULL) {
1016 struct rtable * rt;
1017 if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0)
1018 return err;
1019 dev = rt->u.dst.dev;
1020 ip_rt_put(rt);
1021 if (!dev)
1022 return -EINVAL;
1023 }
1024 switch (dev->type) {
1025 #ifdef CONFIG_FDDI
1026 case ARPHRD_FDDI:
1027 /*
1028 * According to RFC 1390, FDDI devices should accept ARP
1029 * hardware types of 1 (Ethernet). However, to be more
1030 * robust, we'll accept hardware types of either 1 (Ethernet)
1031 * or 6 (IEEE 802.2).
1032 */
1033 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1034 r->arp_ha.sa_family != ARPHRD_ETHER &&
1035 r->arp_ha.sa_family != ARPHRD_IEEE802)
1036 return -EINVAL;
1037 break;
1038 #endif
1039 default:
1040 if (r->arp_ha.sa_family != dev->type)
1041 return -EINVAL;
1042 break;
1043 }
1044
1045 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1046 err = PTR_ERR(neigh);
1047 if (!IS_ERR(neigh)) {
1048 unsigned state = NUD_STALE;
1049 if (r->arp_flags & ATF_PERM)
1050 state = NUD_PERMANENT;
1051 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ?
1052 r->arp_ha.sa_data : NULL, state, 1, 0);
1053 neigh_release(neigh);
1054 }
1055 return err;
1056 }
1057
arp_state_to_flags(struct neighbour * neigh)1058 static unsigned arp_state_to_flags(struct neighbour *neigh)
1059 {
1060 unsigned flags = 0;
1061 if (neigh->nud_state&NUD_PERMANENT)
1062 flags = ATF_PERM|ATF_COM;
1063 else if (neigh->nud_state&NUD_VALID)
1064 flags = ATF_COM;
1065 return flags;
1066 }
1067
1068 /*
1069 * Get an ARP cache entry.
1070 */
1071
arp_req_get(struct arpreq * r,struct net_device * dev)1072 static int arp_req_get(struct arpreq *r, struct net_device *dev)
1073 {
1074 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1075 struct neighbour *neigh;
1076 int err = -ENXIO;
1077
1078 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1079 if (neigh) {
1080 read_lock_bh(&neigh->lock);
1081 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1082 r->arp_flags = arp_state_to_flags(neigh);
1083 read_unlock_bh(&neigh->lock);
1084 r->arp_ha.sa_family = dev->type;
1085 strncpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1086 neigh_release(neigh);
1087 err = 0;
1088 }
1089 return err;
1090 }
1091
arp_req_delete(struct arpreq * r,struct net_device * dev)1092 int arp_req_delete(struct arpreq *r, struct net_device * dev)
1093 {
1094 int err;
1095 u32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1096 struct neighbour *neigh;
1097
1098 if (r->arp_flags & ATF_PUBL) {
1099 u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr;
1100 if (mask == 0xFFFFFFFF)
1101 return pneigh_delete(&arp_tbl, &ip, dev);
1102 if (mask == 0) {
1103 if (dev == NULL) {
1104 ipv4_devconf.proxy_arp = 0;
1105 return 0;
1106 }
1107 if (__in_dev_get(dev)) {
1108 __in_dev_get(dev)->cnf.proxy_arp = 0;
1109 return 0;
1110 }
1111 return -ENXIO;
1112 }
1113 return -EINVAL;
1114 }
1115
1116 if (dev == NULL) {
1117 struct rtable * rt;
1118 if ((err = ip_route_output(&rt, ip, 0, RTO_ONLINK, 0)) != 0)
1119 return err;
1120 dev = rt->u.dst.dev;
1121 ip_rt_put(rt);
1122 if (!dev)
1123 return -EINVAL;
1124 }
1125 err = -ENXIO;
1126 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1127 if (neigh) {
1128 if (neigh->nud_state&~NUD_NOARP)
1129 err = neigh_update(neigh, NULL, NUD_FAILED, 1, 0);
1130 neigh_release(neigh);
1131 }
1132 return err;
1133 }
1134
1135 /*
1136 * Handle an ARP layer I/O control request.
1137 */
1138
arp_ioctl(unsigned int cmd,void * arg)1139 int arp_ioctl(unsigned int cmd, void *arg)
1140 {
1141 int err;
1142 struct arpreq r;
1143 struct net_device * dev = NULL;
1144
1145 switch(cmd) {
1146 case SIOCDARP:
1147 case SIOCSARP:
1148 if (!capable(CAP_NET_ADMIN))
1149 return -EPERM;
1150 case SIOCGARP:
1151 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1152 if (err)
1153 return -EFAULT;
1154 break;
1155 default:
1156 return -EINVAL;
1157 }
1158
1159 if (r.arp_pa.sa_family != AF_INET)
1160 return -EPFNOSUPPORT;
1161
1162 if (!(r.arp_flags & ATF_PUBL) &&
1163 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB)))
1164 return -EINVAL;
1165 if (!(r.arp_flags & ATF_NETMASK))
1166 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr=htonl(0xFFFFFFFFUL);
1167
1168 rtnl_lock();
1169 if (r.arp_dev[0]) {
1170 err = -ENODEV;
1171 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL)
1172 goto out;
1173
1174 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1175 if (!r.arp_ha.sa_family)
1176 r.arp_ha.sa_family = dev->type;
1177 err = -EINVAL;
1178 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1179 goto out;
1180 } else if (cmd == SIOCGARP) {
1181 err = -ENODEV;
1182 goto out;
1183 }
1184
1185 switch(cmd) {
1186 case SIOCDARP:
1187 err = arp_req_delete(&r, dev);
1188 break;
1189 case SIOCSARP:
1190 err = arp_req_set(&r, dev);
1191 break;
1192 case SIOCGARP:
1193 err = arp_req_get(&r, dev);
1194 if (!err && copy_to_user(arg, &r, sizeof(r)))
1195 err = -EFAULT;
1196 break;
1197 }
1198 out:
1199 rtnl_unlock();
1200 return err;
1201 }
1202
1203 #ifdef CONFIG_PROC_FS
1204 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1205
1206 /* ------------------------------------------------------------------------ */
1207 /*
1208 * ax25 -> ASCII conversion
1209 */
ax2asc2(ax25_address * a,char * buf)1210 static char *ax2asc2(ax25_address *a, char *buf)
1211 {
1212 char c, *s;
1213 int n;
1214
1215 for (n = 0, s = buf; n < 6; n++) {
1216 c = (a->ax25_call[n] >> 1) & 0x7F;
1217
1218 if (c != ' ') *s++ = c;
1219 }
1220
1221 *s++ = '-';
1222
1223 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
1224 *s++ = '1';
1225 n -= 10;
1226 }
1227
1228 *s++ = n + '0';
1229 *s++ = '\0';
1230
1231 if (*buf == '\0' || *buf == '-')
1232 return "*";
1233
1234 return buf;
1235
1236 }
1237 #endif /* CONFIG_AX25 */
1238
1239 #define HBUFFERLEN 30
1240
arp_format_neigh_entry(struct seq_file * seq,struct neighbour * n)1241 static void arp_format_neigh_entry(struct seq_file *seq,
1242 struct neighbour *n)
1243 {
1244 char hbuffer[HBUFFERLEN];
1245 const char hexbuf[] = "0123456789ABCDEF";
1246 int k, j;
1247 char tbuf[16];
1248 struct net_device *dev = n->dev;
1249 int hatype = dev->type;
1250
1251 read_lock(&n->lock);
1252
1253 /* Convert hardware address to XX:XX:XX:XX ... form. */
1254 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1255 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1256 ax2asc2((ax25_address *)n->ha, hbuffer);
1257 else {
1258 #endif
1259 for (k=0,j=0;k<HBUFFERLEN-3 && j<dev->addr_len;j++) {
1260 hbuffer[k++]=hexbuf[(n->ha[j]>>4)&15 ];
1261 hbuffer[k++]=hexbuf[n->ha[j]&15 ];
1262 hbuffer[k++]=':';
1263 }
1264 hbuffer[--k]=0;
1265 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1266 }
1267 #endif
1268 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key));
1269 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1270 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1271 read_unlock(&n->lock);
1272 }
1273
arp_format_pneigh_entry(struct seq_file * seq,struct pneigh_entry * n)1274 static void arp_format_pneigh_entry(struct seq_file *seq,
1275 struct pneigh_entry *n)
1276 {
1277 struct net_device *dev = n->dev;
1278 int hatype = dev ? dev->type : 0;
1279 char tbuf[16];
1280
1281 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key));
1282 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1283 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1284 dev ? dev->name : "*");
1285 }
1286
arp_seq_show(struct seq_file * seq,void * v)1287 static int arp_seq_show(struct seq_file *seq, void *v)
1288 {
1289 if (v == SEQ_START_TOKEN) {
1290 seq_puts(seq, "IP address HW type Flags "
1291 "HW address Mask Device\n");
1292 } else {
1293 struct neigh_seq_state *state = seq->private;
1294
1295 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1296 arp_format_pneigh_entry(seq, v);
1297 else
1298 arp_format_neigh_entry(seq, v);
1299 }
1300
1301 return 0;
1302 }
1303
arp_seq_start(struct seq_file * seq,loff_t * pos)1304 static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1305 {
1306 /* Don't want to confuse "arp -a" w/ magic entries,
1307 * so we tell the generic iterator to skip NUD_NOARP.
1308 */
1309 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1310 }
1311
1312 /* ------------------------------------------------------------------------ */
1313
1314 static struct seq_operations arp_seq_ops = {
1315 .start = arp_seq_start,
1316 .next = neigh_seq_next,
1317 .stop = neigh_seq_stop,
1318 .show = arp_seq_show,
1319 };
1320
arp_seq_open(struct inode * inode,struct file * file)1321 static int arp_seq_open(struct inode *inode, struct file *file)
1322 {
1323 struct seq_file *seq;
1324 int rc = -ENOMEM;
1325 struct neigh_seq_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
1326
1327 if (!s)
1328 goto out;
1329
1330 memset(s, 0, sizeof(*s));
1331 rc = seq_open(file, &arp_seq_ops);
1332 if (rc)
1333 goto out_kfree;
1334
1335 seq = file->private_data;
1336 seq->private = s;
1337 out:
1338 return rc;
1339 out_kfree:
1340 kfree(s);
1341 goto out;
1342 }
1343
1344 static struct file_operations arp_seq_fops = {
1345 .owner = THIS_MODULE,
1346 .open = arp_seq_open,
1347 .read = seq_read,
1348 .llseek = seq_lseek,
1349 .release = seq_release_private,
1350 };
1351 #endif /* CONFIG_PROC_FS */
1352
arp_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1353 static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1354 {
1355 struct net_device *dev = ptr;
1356
1357 switch (event) {
1358 case NETDEV_CHANGEADDR:
1359 neigh_changeaddr(&arp_tbl, dev);
1360 rt_cache_flush(0);
1361 break;
1362 default:
1363 break;
1364 }
1365
1366 return NOTIFY_DONE;
1367 }
1368
1369 struct notifier_block arp_netdev_notifier = {
1370 .notifier_call = arp_netdev_event,
1371 };
1372
1373 /* Note, that it is not on notifier chain.
1374 It is necessary, that this routine was called after route cache will be
1375 flushed.
1376 */
arp_ifdown(struct net_device * dev)1377 void arp_ifdown(struct net_device *dev)
1378 {
1379 neigh_ifdown(&arp_tbl, dev);
1380 }
1381
1382
1383 /*
1384 * Called once on startup.
1385 */
1386
1387 static struct packet_type arp_packet_type = {
1388 type: __constant_htons(ETH_P_ARP),
1389 func: arp_rcv,
1390 data: (void*) 1, /* understand shared skbs */
1391 };
1392
arp_init(void)1393 void __init arp_init (void)
1394 {
1395 neigh_table_init(&arp_tbl);
1396
1397 dev_add_pack(&arp_packet_type);
1398
1399 #ifdef CONFIG_PROC_FS
1400 if (!proc_net_fops_create("arp", S_IRUGO, &arp_seq_fops))
1401 panic("unable to create arp proc entry");
1402 #endif
1403 #ifdef CONFIG_SYSCTL
1404 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, NET_IPV4_NEIGH, "ipv4");
1405 #endif
1406 register_netdevice_notifier(&arp_netdev_notifier);
1407 }
1408
1409
1410