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1 | /* |
2 | * AARP: An implementation of the AppleTalk AARP protocol for |
3 | * Ethernet 'ELAP'. |
4 | * |
5 | * Alan Cox <Alan.Cox@linux.org> |
6 | * |
7 | * This doesn't fit cleanly with the IP arp. Potentially we can use |
8 | * the generic neighbour discovery code to clean this up. |
9 | * |
10 | * FIXME: |
11 | * We ought to handle the retransmits with a single list and a |
12 | * separate fast timer for when it is needed. |
13 | * Use neighbour discovery code. |
14 | * Token Ring Support. |
15 | * |
16 | * This program is free software; you can redistribute it and/or |
17 | * modify it under the terms of the GNU General Public License |
18 | * as published by the Free Software Foundation; either version |
19 | * 2 of the License, or (at your option) any later version. |
20 | * |
21 | * |
22 | * References: |
23 | * Inside AppleTalk (2nd Ed). |
24 | * Fixes: |
25 | * Jaume Grau - flush caches on AARP_PROBE |
26 | * Rob Newberry - Added proxy AARP and AARP proc fs, |
27 | * moved probing from DDP module. |
28 | * Arnaldo C. Melo - don't mangle rx packets |
29 | * |
30 | */ |
31 | |
32 | #include <linux/if_arp.h> |
33 | #include <linux/slab.h> |
34 | #include <net/sock.h> |
35 | #include <net/datalink.h> |
36 | #include <net/psnap.h> |
37 | #include <linux/atalk.h> |
38 | #include <linux/delay.h> |
39 | #include <linux/init.h> |
40 | #include <linux/proc_fs.h> |
41 | #include <linux/seq_file.h> |
42 | |
43 | int sysctl_aarp_expiry_time = AARP_EXPIRY_TIME; |
44 | int sysctl_aarp_tick_time = AARP_TICK_TIME; |
45 | int sysctl_aarp_retransmit_limit = AARP_RETRANSMIT_LIMIT; |
46 | int sysctl_aarp_resolve_time = AARP_RESOLVE_TIME; |
47 | |
48 | /* Lists of aarp entries */ |
49 | /** |
50 | * struct aarp_entry - AARP entry |
51 | * @last_sent - Last time we xmitted the aarp request |
52 | * @packet_queue - Queue of frames wait for resolution |
53 | * @status - Used for proxy AARP |
54 | * expires_at - Entry expiry time |
55 | * target_addr - DDP Address |
56 | * dev - Device to use |
57 | * hwaddr - Physical i/f address of target/router |
58 | * xmit_count - When this hits 10 we give up |
59 | * next - Next entry in chain |
60 | */ |
61 | struct aarp_entry { |
62 | /* These first two are only used for unresolved entries */ |
63 | unsigned long last_sent; |
64 | struct sk_buff_head packet_queue; |
65 | int status; |
66 | unsigned long expires_at; |
67 | struct atalk_addr target_addr; |
68 | struct net_device *dev; |
69 | char hwaddr[6]; |
70 | unsigned short xmit_count; |
71 | struct aarp_entry *next; |
72 | }; |
73 | |
74 | /* Hashed list of resolved, unresolved and proxy entries */ |
75 | static struct aarp_entry *resolved[AARP_HASH_SIZE]; |
76 | static struct aarp_entry *unresolved[AARP_HASH_SIZE]; |
77 | static struct aarp_entry *proxies[AARP_HASH_SIZE]; |
78 | static int unresolved_count; |
79 | |
80 | /* One lock protects it all. */ |
81 | static DEFINE_RWLOCK(aarp_lock); |
82 | |
83 | /* Used to walk the list and purge/kick entries. */ |
84 | static struct timer_list aarp_timer; |
85 | |
86 | /* |
87 | * Delete an aarp queue |
88 | * |
89 | * Must run under aarp_lock. |
90 | */ |
91 | static void __aarp_expire(struct aarp_entry *a) |
92 | { |
93 | skb_queue_purge(&a->packet_queue); |
94 | kfree(a); |
95 | } |
96 | |
97 | /* |
98 | * Send an aarp queue entry request |
99 | * |
100 | * Must run under aarp_lock. |
101 | */ |
102 | static void __aarp_send_query(struct aarp_entry *a) |
103 | { |
104 | static unsigned char aarp_eth_multicast[ETH_ALEN] = |
105 | { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; |
106 | struct net_device *dev = a->dev; |
107 | struct elapaarp *eah; |
108 | int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; |
109 | struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); |
110 | struct atalk_addr *sat = atalk_find_dev_addr(dev); |
111 | |
112 | if (!skb) |
113 | return; |
114 | |
115 | if (!sat) { |
116 | kfree_skb(skb); |
117 | return; |
118 | } |
119 | |
120 | /* Set up the buffer */ |
121 | skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length); |
122 | skb_reset_network_header(skb); |
123 | skb_reset_transport_header(skb); |
124 | skb_put(skb, sizeof(*eah)); |
125 | skb->protocol = htons(ETH_P_ATALK); |
126 | skb->dev = dev; |
127 | eah = aarp_hdr(skb); |
128 | |
129 | /* Set up the ARP */ |
130 | eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); |
131 | eah->pa_type = htons(ETH_P_ATALK); |
132 | eah->hw_len = ETH_ALEN; |
133 | eah->pa_len = AARP_PA_ALEN; |
134 | eah->function = htons(AARP_REQUEST); |
135 | |
136 | memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN); |
137 | |
138 | eah->pa_src_zero = 0; |
139 | eah->pa_src_net = sat->s_net; |
140 | eah->pa_src_node = sat->s_node; |
141 | |
142 | memset(eah->hw_dst, '\0', ETH_ALEN); |
143 | |
144 | eah->pa_dst_zero = 0; |
145 | eah->pa_dst_net = a->target_addr.s_net; |
146 | eah->pa_dst_node = a->target_addr.s_node; |
147 | |
148 | /* Send it */ |
149 | aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); |
150 | /* Update the sending count */ |
151 | a->xmit_count++; |
152 | a->last_sent = jiffies; |
153 | } |
154 | |
155 | /* This runs under aarp_lock and in softint context, so only atomic memory |
156 | * allocations can be used. */ |
157 | static void aarp_send_reply(struct net_device *dev, struct atalk_addr *us, |
158 | struct atalk_addr *them, unsigned char *sha) |
159 | { |
160 | struct elapaarp *eah; |
161 | int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; |
162 | struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); |
163 | |
164 | if (!skb) |
165 | return; |
166 | |
167 | /* Set up the buffer */ |
168 | skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length); |
169 | skb_reset_network_header(skb); |
170 | skb_reset_transport_header(skb); |
171 | skb_put(skb, sizeof(*eah)); |
172 | skb->protocol = htons(ETH_P_ATALK); |
173 | skb->dev = dev; |
174 | eah = aarp_hdr(skb); |
175 | |
176 | /* Set up the ARP */ |
177 | eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); |
178 | eah->pa_type = htons(ETH_P_ATALK); |
179 | eah->hw_len = ETH_ALEN; |
180 | eah->pa_len = AARP_PA_ALEN; |
181 | eah->function = htons(AARP_REPLY); |
182 | |
183 | memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN); |
184 | |
185 | eah->pa_src_zero = 0; |
186 | eah->pa_src_net = us->s_net; |
187 | eah->pa_src_node = us->s_node; |
188 | |
189 | if (!sha) |
190 | memset(eah->hw_dst, '\0', ETH_ALEN); |
191 | else |
192 | memcpy(eah->hw_dst, sha, ETH_ALEN); |
193 | |
194 | eah->pa_dst_zero = 0; |
195 | eah->pa_dst_net = them->s_net; |
196 | eah->pa_dst_node = them->s_node; |
197 | |
198 | /* Send it */ |
199 | aarp_dl->request(aarp_dl, skb, sha); |
200 | } |
201 | |
202 | /* |
203 | * Send probe frames. Called from aarp_probe_network and |
204 | * aarp_proxy_probe_network. |
205 | */ |
206 | |
207 | static void aarp_send_probe(struct net_device *dev, struct atalk_addr *us) |
208 | { |
209 | struct elapaarp *eah; |
210 | int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; |
211 | struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); |
212 | static unsigned char aarp_eth_multicast[ETH_ALEN] = |
213 | { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; |
214 | |
215 | if (!skb) |
216 | return; |
217 | |
218 | /* Set up the buffer */ |
219 | skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length); |
220 | skb_reset_network_header(skb); |
221 | skb_reset_transport_header(skb); |
222 | skb_put(skb, sizeof(*eah)); |
223 | skb->protocol = htons(ETH_P_ATALK); |
224 | skb->dev = dev; |
225 | eah = aarp_hdr(skb); |
226 | |
227 | /* Set up the ARP */ |
228 | eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); |
229 | eah->pa_type = htons(ETH_P_ATALK); |
230 | eah->hw_len = ETH_ALEN; |
231 | eah->pa_len = AARP_PA_ALEN; |
232 | eah->function = htons(AARP_PROBE); |
233 | |
234 | memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN); |
235 | |
236 | eah->pa_src_zero = 0; |
237 | eah->pa_src_net = us->s_net; |
238 | eah->pa_src_node = us->s_node; |
239 | |
240 | memset(eah->hw_dst, '\0', ETH_ALEN); |
241 | |
242 | eah->pa_dst_zero = 0; |
243 | eah->pa_dst_net = us->s_net; |
244 | eah->pa_dst_node = us->s_node; |
245 | |
246 | /* Send it */ |
247 | aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); |
248 | } |
249 | |
250 | /* |
251 | * Handle an aarp timer expire |
252 | * |
253 | * Must run under the aarp_lock. |
254 | */ |
255 | |
256 | static void __aarp_expire_timer(struct aarp_entry **n) |
257 | { |
258 | struct aarp_entry *t; |
259 | |
260 | while (*n) |
261 | /* Expired ? */ |
262 | if (time_after(jiffies, (*n)->expires_at)) { |
263 | t = *n; |
264 | *n = (*n)->next; |
265 | __aarp_expire(t); |
266 | } else |
267 | n = &((*n)->next); |
268 | } |
269 | |
270 | /* |
271 | * Kick all pending requests 5 times a second. |
272 | * |
273 | * Must run under the aarp_lock. |
274 | */ |
275 | static void __aarp_kick(struct aarp_entry **n) |
276 | { |
277 | struct aarp_entry *t; |
278 | |
279 | while (*n) |
280 | /* Expired: if this will be the 11th tx, we delete instead. */ |
281 | if ((*n)->xmit_count >= sysctl_aarp_retransmit_limit) { |
282 | t = *n; |
283 | *n = (*n)->next; |
284 | __aarp_expire(t); |
285 | } else { |
286 | __aarp_send_query(*n); |
287 | n = &((*n)->next); |
288 | } |
289 | } |
290 | |
291 | /* |
292 | * A device has gone down. Take all entries referring to the device |
293 | * and remove them. |
294 | * |
295 | * Must run under the aarp_lock. |
296 | */ |
297 | static void __aarp_expire_device(struct aarp_entry **n, struct net_device *dev) |
298 | { |
299 | struct aarp_entry *t; |
300 | |
301 | while (*n) |
302 | if ((*n)->dev == dev) { |
303 | t = *n; |
304 | *n = (*n)->next; |
305 | __aarp_expire(t); |
306 | } else |
307 | n = &((*n)->next); |
308 | } |
309 | |
310 | /* Handle the timer event */ |
311 | static void aarp_expire_timeout(unsigned long unused) |
312 | { |
313 | int ct; |
314 | |
315 | write_lock_bh(&aarp_lock); |
316 | |
317 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
318 | __aarp_expire_timer(&resolved[ct]); |
319 | __aarp_kick(&unresolved[ct]); |
320 | __aarp_expire_timer(&unresolved[ct]); |
321 | __aarp_expire_timer(&proxies[ct]); |
322 | } |
323 | |
324 | write_unlock_bh(&aarp_lock); |
325 | mod_timer(&aarp_timer, jiffies + |
326 | (unresolved_count ? sysctl_aarp_tick_time : |
327 | sysctl_aarp_expiry_time)); |
328 | } |
329 | |
330 | /* Network device notifier chain handler. */ |
331 | static int aarp_device_event(struct notifier_block *this, unsigned long event, |
332 | void *ptr) |
333 | { |
334 | struct net_device *dev = ptr; |
335 | int ct; |
336 | |
337 | if (!net_eq(dev_net(dev), &init_net)) |
338 | return NOTIFY_DONE; |
339 | |
340 | if (event == NETDEV_DOWN) { |
341 | write_lock_bh(&aarp_lock); |
342 | |
343 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
344 | __aarp_expire_device(&resolved[ct], dev); |
345 | __aarp_expire_device(&unresolved[ct], dev); |
346 | __aarp_expire_device(&proxies[ct], dev); |
347 | } |
348 | |
349 | write_unlock_bh(&aarp_lock); |
350 | } |
351 | return NOTIFY_DONE; |
352 | } |
353 | |
354 | /* Expire all entries in a hash chain */ |
355 | static void __aarp_expire_all(struct aarp_entry **n) |
356 | { |
357 | struct aarp_entry *t; |
358 | |
359 | while (*n) { |
360 | t = *n; |
361 | *n = (*n)->next; |
362 | __aarp_expire(t); |
363 | } |
364 | } |
365 | |
366 | /* Cleanup all hash chains -- module unloading */ |
367 | static void aarp_purge(void) |
368 | { |
369 | int ct; |
370 | |
371 | write_lock_bh(&aarp_lock); |
372 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
373 | __aarp_expire_all(&resolved[ct]); |
374 | __aarp_expire_all(&unresolved[ct]); |
375 | __aarp_expire_all(&proxies[ct]); |
376 | } |
377 | write_unlock_bh(&aarp_lock); |
378 | } |
379 | |
380 | /* |
381 | * Create a new aarp entry. This must use GFP_ATOMIC because it |
382 | * runs while holding spinlocks. |
383 | */ |
384 | static struct aarp_entry *aarp_alloc(void) |
385 | { |
386 | struct aarp_entry *a = kmalloc(sizeof(*a), GFP_ATOMIC); |
387 | |
388 | if (a) |
389 | skb_queue_head_init(&a->packet_queue); |
390 | return a; |
391 | } |
392 | |
393 | /* |
394 | * Find an entry. We might return an expired but not yet purged entry. We |
395 | * don't care as it will do no harm. |
396 | * |
397 | * This must run under the aarp_lock. |
398 | */ |
399 | static struct aarp_entry *__aarp_find_entry(struct aarp_entry *list, |
400 | struct net_device *dev, |
401 | struct atalk_addr *sat) |
402 | { |
403 | while (list) { |
404 | if (list->target_addr.s_net == sat->s_net && |
405 | list->target_addr.s_node == sat->s_node && |
406 | list->dev == dev) |
407 | break; |
408 | list = list->next; |
409 | } |
410 | |
411 | return list; |
412 | } |
413 | |
414 | /* Called from the DDP code, and thus must be exported. */ |
415 | void aarp_proxy_remove(struct net_device *dev, struct atalk_addr *sa) |
416 | { |
417 | int hash = sa->s_node % (AARP_HASH_SIZE - 1); |
418 | struct aarp_entry *a; |
419 | |
420 | write_lock_bh(&aarp_lock); |
421 | |
422 | a = __aarp_find_entry(proxies[hash], dev, sa); |
423 | if (a) |
424 | a->expires_at = jiffies - 1; |
425 | |
426 | write_unlock_bh(&aarp_lock); |
427 | } |
428 | |
429 | /* This must run under aarp_lock. */ |
430 | static struct atalk_addr *__aarp_proxy_find(struct net_device *dev, |
431 | struct atalk_addr *sa) |
432 | { |
433 | int hash = sa->s_node % (AARP_HASH_SIZE - 1); |
434 | struct aarp_entry *a = __aarp_find_entry(proxies[hash], dev, sa); |
435 | |
436 | return a ? sa : NULL; |
437 | } |
438 | |
439 | /* |
440 | * Probe a Phase 1 device or a device that requires its Net:Node to |
441 | * be set via an ioctl. |
442 | */ |
443 | static void aarp_send_probe_phase1(struct atalk_iface *iface) |
444 | { |
445 | struct ifreq atreq; |
446 | struct sockaddr_at *sa = (struct sockaddr_at *)&atreq.ifr_addr; |
447 | const struct net_device_ops *ops = iface->dev->netdev_ops; |
448 | |
449 | sa->sat_addr.s_node = iface->address.s_node; |
450 | sa->sat_addr.s_net = ntohs(iface->address.s_net); |
451 | |
452 | /* We pass the Net:Node to the drivers/cards by a Device ioctl. */ |
453 | if (!(ops->ndo_do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) { |
454 | ops->ndo_do_ioctl(iface->dev, &atreq, SIOCGIFADDR); |
455 | if (iface->address.s_net != htons(sa->sat_addr.s_net) || |
456 | iface->address.s_node != sa->sat_addr.s_node) |
457 | iface->status |= ATIF_PROBE_FAIL; |
458 | |
459 | iface->address.s_net = htons(sa->sat_addr.s_net); |
460 | iface->address.s_node = sa->sat_addr.s_node; |
461 | } |
462 | } |
463 | |
464 | |
465 | void aarp_probe_network(struct atalk_iface *atif) |
466 | { |
467 | if (atif->dev->type == ARPHRD_LOCALTLK || |
468 | atif->dev->type == ARPHRD_PPP) |
469 | aarp_send_probe_phase1(atif); |
470 | else { |
471 | unsigned int count; |
472 | |
473 | for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { |
474 | aarp_send_probe(atif->dev, &atif->address); |
475 | |
476 | /* Defer 1/10th */ |
477 | msleep(100); |
478 | |
479 | if (atif->status & ATIF_PROBE_FAIL) |
480 | break; |
481 | } |
482 | } |
483 | } |
484 | |
485 | int aarp_proxy_probe_network(struct atalk_iface *atif, struct atalk_addr *sa) |
486 | { |
487 | int hash, retval = -EPROTONOSUPPORT; |
488 | struct aarp_entry *entry; |
489 | unsigned int count; |
490 | |
491 | /* |
492 | * we don't currently support LocalTalk or PPP for proxy AARP; |
493 | * if someone wants to try and add it, have fun |
494 | */ |
495 | if (atif->dev->type == ARPHRD_LOCALTLK || |
496 | atif->dev->type == ARPHRD_PPP) |
497 | goto out; |
498 | |
499 | /* |
500 | * create a new AARP entry with the flags set to be published -- |
501 | * we need this one to hang around even if it's in use |
502 | */ |
503 | entry = aarp_alloc(); |
504 | retval = -ENOMEM; |
505 | if (!entry) |
506 | goto out; |
507 | |
508 | entry->expires_at = -1; |
509 | entry->status = ATIF_PROBE; |
510 | entry->target_addr.s_node = sa->s_node; |
511 | entry->target_addr.s_net = sa->s_net; |
512 | entry->dev = atif->dev; |
513 | |
514 | write_lock_bh(&aarp_lock); |
515 | |
516 | hash = sa->s_node % (AARP_HASH_SIZE - 1); |
517 | entry->next = proxies[hash]; |
518 | proxies[hash] = entry; |
519 | |
520 | for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { |
521 | aarp_send_probe(atif->dev, sa); |
522 | |
523 | /* Defer 1/10th */ |
524 | write_unlock_bh(&aarp_lock); |
525 | msleep(100); |
526 | write_lock_bh(&aarp_lock); |
527 | |
528 | if (entry->status & ATIF_PROBE_FAIL) |
529 | break; |
530 | } |
531 | |
532 | if (entry->status & ATIF_PROBE_FAIL) { |
533 | entry->expires_at = jiffies - 1; /* free the entry */ |
534 | retval = -EADDRINUSE; /* return network full */ |
535 | } else { /* clear the probing flag */ |
536 | entry->status &= ~ATIF_PROBE; |
537 | retval = 1; |
538 | } |
539 | |
540 | write_unlock_bh(&aarp_lock); |
541 | out: |
542 | return retval; |
543 | } |
544 | |
545 | /* Send a DDP frame */ |
546 | int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb, |
547 | struct atalk_addr *sa, void *hwaddr) |
548 | { |
549 | static char ddp_eth_multicast[ETH_ALEN] = |
550 | { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; |
551 | int hash; |
552 | struct aarp_entry *a; |
553 | |
554 | skb_reset_network_header(skb); |
555 | |
556 | /* Check for LocalTalk first */ |
557 | if (dev->type == ARPHRD_LOCALTLK) { |
558 | struct atalk_addr *at = atalk_find_dev_addr(dev); |
559 | struct ddpehdr *ddp = (struct ddpehdr *)skb->data; |
560 | int ft = 2; |
561 | |
562 | /* |
563 | * Compressible ? |
564 | * |
565 | * IFF: src_net == dest_net == device_net |
566 | * (zero matches anything) |
567 | */ |
568 | |
569 | if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) && |
570 | (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) { |
571 | skb_pull(skb, sizeof(*ddp) - 4); |
572 | |
573 | /* |
574 | * The upper two remaining bytes are the port |
575 | * numbers we just happen to need. Now put the |
576 | * length in the lower two. |
577 | */ |
578 | *((__be16 *)skb->data) = htons(skb->len); |
579 | ft = 1; |
580 | } |
581 | /* |
582 | * Nice and easy. No AARP type protocols occur here so we can |
583 | * just shovel it out with a 3 byte LLAP header |
584 | */ |
585 | |
586 | skb_push(skb, 3); |
587 | skb->data[0] = sa->s_node; |
588 | skb->data[1] = at->s_node; |
589 | skb->data[2] = ft; |
590 | skb->dev = dev; |
591 | goto sendit; |
592 | } |
593 | |
594 | /* On a PPP link we neither compress nor aarp. */ |
595 | if (dev->type == ARPHRD_PPP) { |
596 | skb->protocol = htons(ETH_P_PPPTALK); |
597 | skb->dev = dev; |
598 | goto sendit; |
599 | } |
600 | |
601 | /* Non ELAP we cannot do. */ |
602 | if (dev->type != ARPHRD_ETHER) |
603 | goto free_it; |
604 | |
605 | skb->dev = dev; |
606 | skb->protocol = htons(ETH_P_ATALK); |
607 | hash = sa->s_node % (AARP_HASH_SIZE - 1); |
608 | |
609 | /* Do we have a resolved entry? */ |
610 | if (sa->s_node == ATADDR_BCAST) { |
611 | /* Send it */ |
612 | ddp_dl->request(ddp_dl, skb, ddp_eth_multicast); |
613 | goto sent; |
614 | } |
615 | |
616 | write_lock_bh(&aarp_lock); |
617 | a = __aarp_find_entry(resolved[hash], dev, sa); |
618 | |
619 | if (a) { /* Return 1 and fill in the address */ |
620 | a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10); |
621 | ddp_dl->request(ddp_dl, skb, a->hwaddr); |
622 | write_unlock_bh(&aarp_lock); |
623 | goto sent; |
624 | } |
625 | |
626 | /* Do we have an unresolved entry: This is the less common path */ |
627 | a = __aarp_find_entry(unresolved[hash], dev, sa); |
628 | if (a) { /* Queue onto the unresolved queue */ |
629 | skb_queue_tail(&a->packet_queue, skb); |
630 | goto out_unlock; |
631 | } |
632 | |
633 | /* Allocate a new entry */ |
634 | a = aarp_alloc(); |
635 | if (!a) { |
636 | /* Whoops slipped... good job it's an unreliable protocol 8) */ |
637 | write_unlock_bh(&aarp_lock); |
638 | goto free_it; |
639 | } |
640 | |
641 | /* Set up the queue */ |
642 | skb_queue_tail(&a->packet_queue, skb); |
643 | a->expires_at = jiffies + sysctl_aarp_resolve_time; |
644 | a->dev = dev; |
645 | a->next = unresolved[hash]; |
646 | a->target_addr = *sa; |
647 | a->xmit_count = 0; |
648 | unresolved[hash] = a; |
649 | unresolved_count++; |
650 | |
651 | /* Send an initial request for the address */ |
652 | __aarp_send_query(a); |
653 | |
654 | /* |
655 | * Switch to fast timer if needed (That is if this is the first |
656 | * unresolved entry to get added) |
657 | */ |
658 | |
659 | if (unresolved_count == 1) |
660 | mod_timer(&aarp_timer, jiffies + sysctl_aarp_tick_time); |
661 | |
662 | /* Now finally, it is safe to drop the lock. */ |
663 | out_unlock: |
664 | write_unlock_bh(&aarp_lock); |
665 | |
666 | /* Tell the ddp layer we have taken over for this frame. */ |
667 | goto sent; |
668 | |
669 | sendit: |
670 | if (skb->sk) |
671 | skb->priority = skb->sk->sk_priority; |
672 | if (dev_queue_xmit(skb)) |
673 | goto drop; |
674 | sent: |
675 | return NET_XMIT_SUCCESS; |
676 | free_it: |
677 | kfree_skb(skb); |
678 | drop: |
679 | return NET_XMIT_DROP; |
680 | } |
681 | EXPORT_SYMBOL(aarp_send_ddp); |
682 | |
683 | /* |
684 | * An entry in the aarp unresolved queue has become resolved. Send |
685 | * all the frames queued under it. |
686 | * |
687 | * Must run under aarp_lock. |
688 | */ |
689 | static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a, |
690 | int hash) |
691 | { |
692 | struct sk_buff *skb; |
693 | |
694 | while (*list) |
695 | if (*list == a) { |
696 | unresolved_count--; |
697 | *list = a->next; |
698 | |
699 | /* Move into the resolved list */ |
700 | a->next = resolved[hash]; |
701 | resolved[hash] = a; |
702 | |
703 | /* Kick frames off */ |
704 | while ((skb = skb_dequeue(&a->packet_queue)) != NULL) { |
705 | a->expires_at = jiffies + |
706 | sysctl_aarp_expiry_time * 10; |
707 | ddp_dl->request(ddp_dl, skb, a->hwaddr); |
708 | } |
709 | } else |
710 | list = &((*list)->next); |
711 | } |
712 | |
713 | /* |
714 | * This is called by the SNAP driver whenever we see an AARP SNAP |
715 | * frame. We currently only support Ethernet. |
716 | */ |
717 | static int aarp_rcv(struct sk_buff *skb, struct net_device *dev, |
718 | struct packet_type *pt, struct net_device *orig_dev) |
719 | { |
720 | struct elapaarp *ea = aarp_hdr(skb); |
721 | int hash, ret = 0; |
722 | __u16 function; |
723 | struct aarp_entry *a; |
724 | struct atalk_addr sa, *ma, da; |
725 | struct atalk_iface *ifa; |
726 | |
727 | if (!net_eq(dev_net(dev), &init_net)) |
728 | goto out0; |
729 | |
730 | /* We only do Ethernet SNAP AARP. */ |
731 | if (dev->type != ARPHRD_ETHER) |
732 | goto out0; |
733 | |
734 | /* Frame size ok? */ |
735 | if (!skb_pull(skb, sizeof(*ea))) |
736 | goto out0; |
737 | |
738 | function = ntohs(ea->function); |
739 | |
740 | /* Sanity check fields. */ |
741 | if (function < AARP_REQUEST || function > AARP_PROBE || |
742 | ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN || |
743 | ea->pa_src_zero || ea->pa_dst_zero) |
744 | goto out0; |
745 | |
746 | /* Looks good. */ |
747 | hash = ea->pa_src_node % (AARP_HASH_SIZE - 1); |
748 | |
749 | /* Build an address. */ |
750 | sa.s_node = ea->pa_src_node; |
751 | sa.s_net = ea->pa_src_net; |
752 | |
753 | /* Process the packet. Check for replies of me. */ |
754 | ifa = atalk_find_dev(dev); |
755 | if (!ifa) |
756 | goto out1; |
757 | |
758 | if (ifa->status & ATIF_PROBE && |
759 | ifa->address.s_node == ea->pa_dst_node && |
760 | ifa->address.s_net == ea->pa_dst_net) { |
761 | ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */ |
762 | goto out1; |
763 | } |
764 | |
765 | /* Check for replies of proxy AARP entries */ |
766 | da.s_node = ea->pa_dst_node; |
767 | da.s_net = ea->pa_dst_net; |
768 | |
769 | write_lock_bh(&aarp_lock); |
770 | a = __aarp_find_entry(proxies[hash], dev, &da); |
771 | |
772 | if (a && a->status & ATIF_PROBE) { |
773 | a->status |= ATIF_PROBE_FAIL; |
774 | /* |
775 | * we do not respond to probe or request packets for |
776 | * this address while we are probing this address |
777 | */ |
778 | goto unlock; |
779 | } |
780 | |
781 | switch (function) { |
782 | case AARP_REPLY: |
783 | if (!unresolved_count) /* Speed up */ |
784 | break; |
785 | |
786 | /* Find the entry. */ |
787 | a = __aarp_find_entry(unresolved[hash], dev, &sa); |
788 | if (!a || dev != a->dev) |
789 | break; |
790 | |
791 | /* We can fill one in - this is good. */ |
792 | memcpy(a->hwaddr, ea->hw_src, ETH_ALEN); |
793 | __aarp_resolved(&unresolved[hash], a, hash); |
794 | if (!unresolved_count) |
795 | mod_timer(&aarp_timer, |
796 | jiffies + sysctl_aarp_expiry_time); |
797 | break; |
798 | |
799 | case AARP_REQUEST: |
800 | case AARP_PROBE: |
801 | |
802 | /* |
803 | * If it is my address set ma to my address and reply. |
804 | * We can treat probe and request the same. Probe |
805 | * simply means we shouldn't cache the querying host, |
806 | * as in a probe they are proposing an address not |
807 | * using one. |
808 | * |
809 | * Support for proxy-AARP added. We check if the |
810 | * address is one of our proxies before we toss the |
811 | * packet out. |
812 | */ |
813 | |
814 | sa.s_node = ea->pa_dst_node; |
815 | sa.s_net = ea->pa_dst_net; |
816 | |
817 | /* See if we have a matching proxy. */ |
818 | ma = __aarp_proxy_find(dev, &sa); |
819 | if (!ma) |
820 | ma = &ifa->address; |
821 | else { /* We need to make a copy of the entry. */ |
822 | da.s_node = sa.s_node; |
823 | da.s_net = sa.s_net; |
824 | ma = &da; |
825 | } |
826 | |
827 | if (function == AARP_PROBE) { |
828 | /* |
829 | * A probe implies someone trying to get an |
830 | * address. So as a precaution flush any |
831 | * entries we have for this address. |
832 | */ |
833 | a = __aarp_find_entry(resolved[sa.s_node % |
834 | (AARP_HASH_SIZE - 1)], |
835 | skb->dev, &sa); |
836 | |
837 | /* |
838 | * Make it expire next tick - that avoids us |
839 | * getting into a probe/flush/learn/probe/ |
840 | * flush/learn cycle during probing of a slow |
841 | * to respond host addr. |
842 | */ |
843 | if (a) { |
844 | a->expires_at = jiffies - 1; |
845 | mod_timer(&aarp_timer, jiffies + |
846 | sysctl_aarp_tick_time); |
847 | } |
848 | } |
849 | |
850 | if (sa.s_node != ma->s_node) |
851 | break; |
852 | |
853 | if (sa.s_net && ma->s_net && sa.s_net != ma->s_net) |
854 | break; |
855 | |
856 | sa.s_node = ea->pa_src_node; |
857 | sa.s_net = ea->pa_src_net; |
858 | |
859 | /* aarp_my_address has found the address to use for us. |
860 | */ |
861 | aarp_send_reply(dev, ma, &sa, ea->hw_src); |
862 | break; |
863 | } |
864 | |
865 | unlock: |
866 | write_unlock_bh(&aarp_lock); |
867 | out1: |
868 | ret = 1; |
869 | out0: |
870 | kfree_skb(skb); |
871 | return ret; |
872 | } |
873 | |
874 | static struct notifier_block aarp_notifier = { |
875 | .notifier_call = aarp_device_event, |
876 | }; |
877 | |
878 | static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 }; |
879 | |
880 | void __init aarp_proto_init(void) |
881 | { |
882 | aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv); |
883 | if (!aarp_dl) |
884 | printk(KERN_CRIT "Unable to register AARP with SNAP.\n"); |
885 | setup_timer(&aarp_timer, aarp_expire_timeout, 0); |
886 | aarp_timer.expires = jiffies + sysctl_aarp_expiry_time; |
887 | add_timer(&aarp_timer); |
888 | register_netdevice_notifier(&aarp_notifier); |
889 | } |
890 | |
891 | /* Remove the AARP entries associated with a device. */ |
892 | void aarp_device_down(struct net_device *dev) |
893 | { |
894 | int ct; |
895 | |
896 | write_lock_bh(&aarp_lock); |
897 | |
898 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
899 | __aarp_expire_device(&resolved[ct], dev); |
900 | __aarp_expire_device(&unresolved[ct], dev); |
901 | __aarp_expire_device(&proxies[ct], dev); |
902 | } |
903 | |
904 | write_unlock_bh(&aarp_lock); |
905 | } |
906 | |
907 | #ifdef CONFIG_PROC_FS |
908 | struct aarp_iter_state { |
909 | int bucket; |
910 | struct aarp_entry **table; |
911 | }; |
912 | |
913 | /* |
914 | * Get the aarp entry that is in the chain described |
915 | * by the iterator. |
916 | * If pos is set then skip till that index. |
917 | * pos = 1 is the first entry |
918 | */ |
919 | static struct aarp_entry *iter_next(struct aarp_iter_state *iter, loff_t *pos) |
920 | { |
921 | int ct = iter->bucket; |
922 | struct aarp_entry **table = iter->table; |
923 | loff_t off = 0; |
924 | struct aarp_entry *entry; |
925 | |
926 | rescan: |
927 | while(ct < AARP_HASH_SIZE) { |
928 | for (entry = table[ct]; entry; entry = entry->next) { |
929 | if (!pos || ++off == *pos) { |
930 | iter->table = table; |
931 | iter->bucket = ct; |
932 | return entry; |
933 | } |
934 | } |
935 | ++ct; |
936 | } |
937 | |
938 | if (table == resolved) { |
939 | ct = 0; |
940 | table = unresolved; |
941 | goto rescan; |
942 | } |
943 | if (table == unresolved) { |
944 | ct = 0; |
945 | table = proxies; |
946 | goto rescan; |
947 | } |
948 | return NULL; |
949 | } |
950 | |
951 | static void *aarp_seq_start(struct seq_file *seq, loff_t *pos) |
952 | __acquires(aarp_lock) |
953 | { |
954 | struct aarp_iter_state *iter = seq->private; |
955 | |
956 | read_lock_bh(&aarp_lock); |
957 | iter->table = resolved; |
958 | iter->bucket = 0; |
959 | |
960 | return *pos ? iter_next(iter, pos) : SEQ_START_TOKEN; |
961 | } |
962 | |
963 | static void *aarp_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
964 | { |
965 | struct aarp_entry *entry = v; |
966 | struct aarp_iter_state *iter = seq->private; |
967 | |
968 | ++*pos; |
969 | |
970 | /* first line after header */ |
971 | if (v == SEQ_START_TOKEN) |
972 | entry = iter_next(iter, NULL); |
973 | |
974 | /* next entry in current bucket */ |
975 | else if (entry->next) |
976 | entry = entry->next; |
977 | |
978 | /* next bucket or table */ |
979 | else { |
980 | ++iter->bucket; |
981 | entry = iter_next(iter, NULL); |
982 | } |
983 | return entry; |
984 | } |
985 | |
986 | static void aarp_seq_stop(struct seq_file *seq, void *v) |
987 | __releases(aarp_lock) |
988 | { |
989 | read_unlock_bh(&aarp_lock); |
990 | } |
991 | |
992 | static const char *dt2str(unsigned long ticks) |
993 | { |
994 | static char buf[32]; |
995 | |
996 | sprintf(buf, "%ld.%02ld", ticks / HZ, ((ticks % HZ) * 100 ) / HZ); |
997 | |
998 | return buf; |
999 | } |
1000 | |
1001 | static int aarp_seq_show(struct seq_file *seq, void *v) |
1002 | { |
1003 | struct aarp_iter_state *iter = seq->private; |
1004 | struct aarp_entry *entry = v; |
1005 | unsigned long now = jiffies; |
1006 | |
1007 | if (v == SEQ_START_TOKEN) |
1008 | seq_puts(seq, |
1009 | "Address Interface Hardware Address" |
1010 | " Expires LastSend Retry Status\n"); |
1011 | else { |
1012 | seq_printf(seq, "%04X:%02X %-12s", |
1013 | ntohs(entry->target_addr.s_net), |
1014 | (unsigned int) entry->target_addr.s_node, |
1015 | entry->dev ? entry->dev->name : "????"); |
1016 | seq_printf(seq, "%pM", entry->hwaddr); |
1017 | seq_printf(seq, " %8s", |
1018 | dt2str((long)entry->expires_at - (long)now)); |
1019 | if (iter->table == unresolved) |
1020 | seq_printf(seq, " %8s %6hu", |
1021 | dt2str(now - entry->last_sent), |
1022 | entry->xmit_count); |
1023 | else |
1024 | seq_puts(seq, " "); |
1025 | seq_printf(seq, " %s\n", |
1026 | (iter->table == resolved) ? "resolved" |
1027 | : (iter->table == unresolved) ? "unresolved" |
1028 | : (iter->table == proxies) ? "proxies" |
1029 | : "unknown"); |
1030 | } |
1031 | return 0; |
1032 | } |
1033 | |
1034 | static const struct seq_operations aarp_seq_ops = { |
1035 | .start = aarp_seq_start, |
1036 | .next = aarp_seq_next, |
1037 | .stop = aarp_seq_stop, |
1038 | .show = aarp_seq_show, |
1039 | }; |
1040 | |
1041 | static int aarp_seq_open(struct inode *inode, struct file *file) |
1042 | { |
1043 | return seq_open_private(file, &aarp_seq_ops, |
1044 | sizeof(struct aarp_iter_state)); |
1045 | } |
1046 | |
1047 | const struct file_operations atalk_seq_arp_fops = { |
1048 | .owner = THIS_MODULE, |
1049 | .open = aarp_seq_open, |
1050 | .read = seq_read, |
1051 | .llseek = seq_lseek, |
1052 | .release = seq_release_private, |
1053 | }; |
1054 | #endif |
1055 | |
1056 | /* General module cleanup. Called from cleanup_module() in ddp.c. */ |
1057 | void aarp_cleanup_module(void) |
1058 | { |
1059 | del_timer_sync(&aarp_timer); |
1060 | unregister_netdevice_notifier(&aarp_notifier); |
1061 | unregister_snap_client(aarp_dl); |
1062 | aarp_purge(); |
1063 | } |
1064 |
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