1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * AARP: An implementation of the AppleTalk AARP protocol for |
4 | * Ethernet 'ELAP'. |
5 | * |
6 | * Alan Cox <Alan.Cox@linux.org> |
7 | * |
8 | * This doesn't fit cleanly with the IP arp. Potentially we can use |
9 | * the generic neighbour discovery code to clean this up. |
10 | * |
11 | * FIXME: |
12 | * We ought to handle the retransmits with a single list and a |
13 | * separate fast timer for when it is needed. |
14 | * Use neighbour discovery code. |
15 | * Token Ring Support. |
16 | * |
17 | * References: |
18 | * Inside AppleTalk (2nd Ed). |
19 | * Fixes: |
20 | * Jaume Grau - flush caches on AARP_PROBE |
21 | * Rob Newberry - Added proxy AARP and AARP proc fs, |
22 | * moved probing from DDP module. |
23 | * Arnaldo C. Melo - don't mangle rx packets |
24 | */ |
25 | |
26 | #include <linux/if_arp.h> |
27 | #include <linux/slab.h> |
28 | #include <net/sock.h> |
29 | #include <net/datalink.h> |
30 | #include <net/psnap.h> |
31 | #include <linux/atalk.h> |
32 | #include <linux/delay.h> |
33 | #include <linux/init.h> |
34 | #include <linux/proc_fs.h> |
35 | #include <linux/seq_file.h> |
36 | #include <linux/export.h> |
37 | #include <linux/etherdevice.h> |
38 | |
39 | int sysctl_aarp_expiry_time = AARP_EXPIRY_TIME; |
40 | int sysctl_aarp_tick_time = AARP_TICK_TIME; |
41 | int sysctl_aarp_retransmit_limit = AARP_RETRANSMIT_LIMIT; |
42 | int sysctl_aarp_resolve_time = AARP_RESOLVE_TIME; |
43 | |
44 | /* Lists of aarp entries */ |
45 | /** |
46 | * struct aarp_entry - AARP entry |
47 | * @last_sent: Last time we xmitted the aarp request |
48 | * @packet_queue: Queue of frames wait for resolution |
49 | * @status: Used for proxy AARP |
50 | * @expires_at: Entry expiry time |
51 | * @target_addr: DDP Address |
52 | * @dev: Device to use |
53 | * @hwaddr: Physical i/f address of target/router |
54 | * @xmit_count: When this hits 10 we give up |
55 | * @next: Next entry in chain |
56 | */ |
57 | struct aarp_entry { |
58 | /* These first two are only used for unresolved entries */ |
59 | unsigned long last_sent; |
60 | struct sk_buff_head packet_queue; |
61 | int status; |
62 | unsigned long expires_at; |
63 | struct atalk_addr target_addr; |
64 | struct net_device *dev; |
65 | char hwaddr[ETH_ALEN]; |
66 | unsigned short xmit_count; |
67 | struct aarp_entry *next; |
68 | }; |
69 | |
70 | /* Hashed list of resolved, unresolved and proxy entries */ |
71 | static struct aarp_entry *resolved[AARP_HASH_SIZE]; |
72 | static struct aarp_entry *unresolved[AARP_HASH_SIZE]; |
73 | static struct aarp_entry *proxies[AARP_HASH_SIZE]; |
74 | static int unresolved_count; |
75 | |
76 | /* One lock protects it all. */ |
77 | static DEFINE_RWLOCK(aarp_lock); |
78 | |
79 | /* Used to walk the list and purge/kick entries. */ |
80 | static struct timer_list aarp_timer; |
81 | |
82 | /* |
83 | * Delete an aarp queue |
84 | * |
85 | * Must run under aarp_lock. |
86 | */ |
87 | static void __aarp_expire(struct aarp_entry *a) |
88 | { |
89 | skb_queue_purge(list: &a->packet_queue); |
90 | kfree(objp: a); |
91 | } |
92 | |
93 | /* |
94 | * Send an aarp queue entry request |
95 | * |
96 | * Must run under aarp_lock. |
97 | */ |
98 | static void __aarp_send_query(struct aarp_entry *a) |
99 | { |
100 | static unsigned char aarp_eth_multicast[ETH_ALEN] = |
101 | { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; |
102 | struct net_device *dev = a->dev; |
103 | struct elapaarp *eah; |
104 | int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; |
105 | struct sk_buff *skb = alloc_skb(size: len, GFP_ATOMIC); |
106 | struct atalk_addr *sat = atalk_find_dev_addr(dev); |
107 | |
108 | if (!skb) |
109 | return; |
110 | |
111 | if (!sat) { |
112 | kfree_skb(skb); |
113 | return; |
114 | } |
115 | |
116 | /* Set up the buffer */ |
117 | skb_reserve(skb, len: dev->hard_header_len + aarp_dl->header_length); |
118 | skb_reset_network_header(skb); |
119 | skb_reset_transport_header(skb); |
120 | skb_put(skb, len: sizeof(*eah)); |
121 | skb->protocol = htons(ETH_P_ATALK); |
122 | skb->dev = dev; |
123 | eah = aarp_hdr(skb); |
124 | |
125 | /* Set up the ARP */ |
126 | eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); |
127 | eah->pa_type = htons(ETH_P_ATALK); |
128 | eah->hw_len = ETH_ALEN; |
129 | eah->pa_len = AARP_PA_ALEN; |
130 | eah->function = htons(AARP_REQUEST); |
131 | |
132 | ether_addr_copy(dst: eah->hw_src, src: dev->dev_addr); |
133 | |
134 | eah->pa_src_zero = 0; |
135 | eah->pa_src_net = sat->s_net; |
136 | eah->pa_src_node = sat->s_node; |
137 | |
138 | eth_zero_addr(addr: eah->hw_dst); |
139 | |
140 | eah->pa_dst_zero = 0; |
141 | eah->pa_dst_net = a->target_addr.s_net; |
142 | eah->pa_dst_node = a->target_addr.s_node; |
143 | |
144 | /* Send it */ |
145 | aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); |
146 | /* Update the sending count */ |
147 | a->xmit_count++; |
148 | a->last_sent = jiffies; |
149 | } |
150 | |
151 | /* This runs under aarp_lock and in softint context, so only atomic memory |
152 | * allocations can be used. */ |
153 | static void aarp_send_reply(struct net_device *dev, struct atalk_addr *us, |
154 | struct atalk_addr *them, unsigned char *sha) |
155 | { |
156 | struct elapaarp *eah; |
157 | int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; |
158 | struct sk_buff *skb = alloc_skb(size: len, GFP_ATOMIC); |
159 | |
160 | if (!skb) |
161 | return; |
162 | |
163 | /* Set up the buffer */ |
164 | skb_reserve(skb, len: dev->hard_header_len + aarp_dl->header_length); |
165 | skb_reset_network_header(skb); |
166 | skb_reset_transport_header(skb); |
167 | skb_put(skb, len: sizeof(*eah)); |
168 | skb->protocol = htons(ETH_P_ATALK); |
169 | skb->dev = dev; |
170 | eah = aarp_hdr(skb); |
171 | |
172 | /* Set up the ARP */ |
173 | eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); |
174 | eah->pa_type = htons(ETH_P_ATALK); |
175 | eah->hw_len = ETH_ALEN; |
176 | eah->pa_len = AARP_PA_ALEN; |
177 | eah->function = htons(AARP_REPLY); |
178 | |
179 | ether_addr_copy(dst: eah->hw_src, src: dev->dev_addr); |
180 | |
181 | eah->pa_src_zero = 0; |
182 | eah->pa_src_net = us->s_net; |
183 | eah->pa_src_node = us->s_node; |
184 | |
185 | if (!sha) |
186 | eth_zero_addr(addr: eah->hw_dst); |
187 | else |
188 | ether_addr_copy(dst: eah->hw_dst, src: sha); |
189 | |
190 | eah->pa_dst_zero = 0; |
191 | eah->pa_dst_net = them->s_net; |
192 | eah->pa_dst_node = them->s_node; |
193 | |
194 | /* Send it */ |
195 | aarp_dl->request(aarp_dl, skb, sha); |
196 | } |
197 | |
198 | /* |
199 | * Send probe frames. Called from aarp_probe_network and |
200 | * aarp_proxy_probe_network. |
201 | */ |
202 | |
203 | static void aarp_send_probe(struct net_device *dev, struct atalk_addr *us) |
204 | { |
205 | struct elapaarp *eah; |
206 | int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; |
207 | struct sk_buff *skb = alloc_skb(size: len, GFP_ATOMIC); |
208 | static unsigned char aarp_eth_multicast[ETH_ALEN] = |
209 | { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; |
210 | |
211 | if (!skb) |
212 | return; |
213 | |
214 | /* Set up the buffer */ |
215 | skb_reserve(skb, len: dev->hard_header_len + aarp_dl->header_length); |
216 | skb_reset_network_header(skb); |
217 | skb_reset_transport_header(skb); |
218 | skb_put(skb, len: sizeof(*eah)); |
219 | skb->protocol = htons(ETH_P_ATALK); |
220 | skb->dev = dev; |
221 | eah = aarp_hdr(skb); |
222 | |
223 | /* Set up the ARP */ |
224 | eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); |
225 | eah->pa_type = htons(ETH_P_ATALK); |
226 | eah->hw_len = ETH_ALEN; |
227 | eah->pa_len = AARP_PA_ALEN; |
228 | eah->function = htons(AARP_PROBE); |
229 | |
230 | ether_addr_copy(dst: eah->hw_src, src: dev->dev_addr); |
231 | |
232 | eah->pa_src_zero = 0; |
233 | eah->pa_src_net = us->s_net; |
234 | eah->pa_src_node = us->s_node; |
235 | |
236 | eth_zero_addr(addr: eah->hw_dst); |
237 | |
238 | eah->pa_dst_zero = 0; |
239 | eah->pa_dst_net = us->s_net; |
240 | eah->pa_dst_node = us->s_node; |
241 | |
242 | /* Send it */ |
243 | aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); |
244 | } |
245 | |
246 | /* |
247 | * Handle an aarp timer expire |
248 | * |
249 | * Must run under the aarp_lock. |
250 | */ |
251 | |
252 | static void __aarp_expire_timer(struct aarp_entry **n) |
253 | { |
254 | struct aarp_entry *t; |
255 | |
256 | while (*n) |
257 | /* Expired ? */ |
258 | if (time_after(jiffies, (*n)->expires_at)) { |
259 | t = *n; |
260 | *n = (*n)->next; |
261 | __aarp_expire(a: t); |
262 | } else |
263 | n = &((*n)->next); |
264 | } |
265 | |
266 | /* |
267 | * Kick all pending requests 5 times a second. |
268 | * |
269 | * Must run under the aarp_lock. |
270 | */ |
271 | static void __aarp_kick(struct aarp_entry **n) |
272 | { |
273 | struct aarp_entry *t; |
274 | |
275 | while (*n) |
276 | /* Expired: if this will be the 11th tx, we delete instead. */ |
277 | if ((*n)->xmit_count >= sysctl_aarp_retransmit_limit) { |
278 | t = *n; |
279 | *n = (*n)->next; |
280 | __aarp_expire(a: t); |
281 | } else { |
282 | __aarp_send_query(a: *n); |
283 | n = &((*n)->next); |
284 | } |
285 | } |
286 | |
287 | /* |
288 | * A device has gone down. Take all entries referring to the device |
289 | * and remove them. |
290 | * |
291 | * Must run under the aarp_lock. |
292 | */ |
293 | static void __aarp_expire_device(struct aarp_entry **n, struct net_device *dev) |
294 | { |
295 | struct aarp_entry *t; |
296 | |
297 | while (*n) |
298 | if ((*n)->dev == dev) { |
299 | t = *n; |
300 | *n = (*n)->next; |
301 | __aarp_expire(a: t); |
302 | } else |
303 | n = &((*n)->next); |
304 | } |
305 | |
306 | /* Handle the timer event */ |
307 | static void aarp_expire_timeout(struct timer_list *unused) |
308 | { |
309 | int ct; |
310 | |
311 | write_lock_bh(&aarp_lock); |
312 | |
313 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
314 | __aarp_expire_timer(n: &resolved[ct]); |
315 | __aarp_kick(n: &unresolved[ct]); |
316 | __aarp_expire_timer(n: &unresolved[ct]); |
317 | __aarp_expire_timer(n: &proxies[ct]); |
318 | } |
319 | |
320 | write_unlock_bh(&aarp_lock); |
321 | mod_timer(timer: &aarp_timer, expires: jiffies + |
322 | (unresolved_count ? sysctl_aarp_tick_time : |
323 | sysctl_aarp_expiry_time)); |
324 | } |
325 | |
326 | /* Network device notifier chain handler. */ |
327 | static int aarp_device_event(struct notifier_block *this, unsigned long event, |
328 | void *ptr) |
329 | { |
330 | struct net_device *dev = netdev_notifier_info_to_dev(info: ptr); |
331 | int ct; |
332 | |
333 | if (!net_eq(net1: dev_net(dev), net2: &init_net)) |
334 | return NOTIFY_DONE; |
335 | |
336 | if (event == NETDEV_DOWN) { |
337 | write_lock_bh(&aarp_lock); |
338 | |
339 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
340 | __aarp_expire_device(n: &resolved[ct], dev); |
341 | __aarp_expire_device(n: &unresolved[ct], dev); |
342 | __aarp_expire_device(n: &proxies[ct], dev); |
343 | } |
344 | |
345 | write_unlock_bh(&aarp_lock); |
346 | } |
347 | return NOTIFY_DONE; |
348 | } |
349 | |
350 | /* Expire all entries in a hash chain */ |
351 | static void __aarp_expire_all(struct aarp_entry **n) |
352 | { |
353 | struct aarp_entry *t; |
354 | |
355 | while (*n) { |
356 | t = *n; |
357 | *n = (*n)->next; |
358 | __aarp_expire(a: t); |
359 | } |
360 | } |
361 | |
362 | /* Cleanup all hash chains -- module unloading */ |
363 | static void aarp_purge(void) |
364 | { |
365 | int ct; |
366 | |
367 | write_lock_bh(&aarp_lock); |
368 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
369 | __aarp_expire_all(n: &resolved[ct]); |
370 | __aarp_expire_all(n: &unresolved[ct]); |
371 | __aarp_expire_all(n: &proxies[ct]); |
372 | } |
373 | write_unlock_bh(&aarp_lock); |
374 | } |
375 | |
376 | /* |
377 | * Create a new aarp entry. This must use GFP_ATOMIC because it |
378 | * runs while holding spinlocks. |
379 | */ |
380 | static struct aarp_entry *aarp_alloc(void) |
381 | { |
382 | struct aarp_entry *a = kmalloc(size: sizeof(*a), GFP_ATOMIC); |
383 | |
384 | if (a) |
385 | skb_queue_head_init(list: &a->packet_queue); |
386 | return a; |
387 | } |
388 | |
389 | /* |
390 | * Find an entry. We might return an expired but not yet purged entry. We |
391 | * don't care as it will do no harm. |
392 | * |
393 | * This must run under the aarp_lock. |
394 | */ |
395 | static struct aarp_entry *__aarp_find_entry(struct aarp_entry *list, |
396 | struct net_device *dev, |
397 | struct atalk_addr *sat) |
398 | { |
399 | while (list) { |
400 | if (list->target_addr.s_net == sat->s_net && |
401 | list->target_addr.s_node == sat->s_node && |
402 | list->dev == dev) |
403 | break; |
404 | list = list->next; |
405 | } |
406 | |
407 | return list; |
408 | } |
409 | |
410 | /* Called from the DDP code, and thus must be exported. */ |
411 | void aarp_proxy_remove(struct net_device *dev, struct atalk_addr *sa) |
412 | { |
413 | int hash = sa->s_node % (AARP_HASH_SIZE - 1); |
414 | struct aarp_entry *a; |
415 | |
416 | write_lock_bh(&aarp_lock); |
417 | |
418 | a = __aarp_find_entry(list: proxies[hash], dev, sat: sa); |
419 | if (a) |
420 | a->expires_at = jiffies - 1; |
421 | |
422 | write_unlock_bh(&aarp_lock); |
423 | } |
424 | |
425 | /* This must run under aarp_lock. */ |
426 | static struct atalk_addr *__aarp_proxy_find(struct net_device *dev, |
427 | struct atalk_addr *sa) |
428 | { |
429 | int hash = sa->s_node % (AARP_HASH_SIZE - 1); |
430 | struct aarp_entry *a = __aarp_find_entry(list: proxies[hash], dev, sat: sa); |
431 | |
432 | return a ? sa : NULL; |
433 | } |
434 | |
435 | /* |
436 | * Probe a Phase 1 device or a device that requires its Net:Node to |
437 | * be set via an ioctl. |
438 | */ |
439 | static void aarp_send_probe_phase1(struct atalk_iface *iface) |
440 | { |
441 | struct ifreq atreq; |
442 | struct sockaddr_at *sa = (struct sockaddr_at *)&atreq.ifr_addr; |
443 | const struct net_device_ops *ops = iface->dev->netdev_ops; |
444 | |
445 | sa->sat_addr.s_node = iface->address.s_node; |
446 | sa->sat_addr.s_net = ntohs(iface->address.s_net); |
447 | |
448 | /* We pass the Net:Node to the drivers/cards by a Device ioctl. */ |
449 | if (!(ops->ndo_do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) { |
450 | ops->ndo_do_ioctl(iface->dev, &atreq, SIOCGIFADDR); |
451 | if (iface->address.s_net != htons(sa->sat_addr.s_net) || |
452 | iface->address.s_node != sa->sat_addr.s_node) |
453 | iface->status |= ATIF_PROBE_FAIL; |
454 | |
455 | iface->address.s_net = htons(sa->sat_addr.s_net); |
456 | iface->address.s_node = sa->sat_addr.s_node; |
457 | } |
458 | } |
459 | |
460 | |
461 | void aarp_probe_network(struct atalk_iface *atif) |
462 | { |
463 | if (atif->dev->type == ARPHRD_LOCALTLK || |
464 | atif->dev->type == ARPHRD_PPP) |
465 | aarp_send_probe_phase1(iface: atif); |
466 | else { |
467 | unsigned int count; |
468 | |
469 | for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { |
470 | aarp_send_probe(dev: atif->dev, us: &atif->address); |
471 | |
472 | /* Defer 1/10th */ |
473 | msleep(msecs: 100); |
474 | |
475 | if (atif->status & ATIF_PROBE_FAIL) |
476 | break; |
477 | } |
478 | } |
479 | } |
480 | |
481 | int aarp_proxy_probe_network(struct atalk_iface *atif, struct atalk_addr *sa) |
482 | { |
483 | int hash, retval = -EPROTONOSUPPORT; |
484 | struct aarp_entry *entry; |
485 | unsigned int count; |
486 | |
487 | /* |
488 | * we don't currently support LocalTalk or PPP for proxy AARP; |
489 | * if someone wants to try and add it, have fun |
490 | */ |
491 | if (atif->dev->type == ARPHRD_LOCALTLK || |
492 | atif->dev->type == ARPHRD_PPP) |
493 | goto out; |
494 | |
495 | /* |
496 | * create a new AARP entry with the flags set to be published -- |
497 | * we need this one to hang around even if it's in use |
498 | */ |
499 | entry = aarp_alloc(); |
500 | retval = -ENOMEM; |
501 | if (!entry) |
502 | goto out; |
503 | |
504 | entry->expires_at = -1; |
505 | entry->status = ATIF_PROBE; |
506 | entry->target_addr.s_node = sa->s_node; |
507 | entry->target_addr.s_net = sa->s_net; |
508 | entry->dev = atif->dev; |
509 | |
510 | write_lock_bh(&aarp_lock); |
511 | |
512 | hash = sa->s_node % (AARP_HASH_SIZE - 1); |
513 | entry->next = proxies[hash]; |
514 | proxies[hash] = entry; |
515 | |
516 | for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { |
517 | aarp_send_probe(dev: atif->dev, us: sa); |
518 | |
519 | /* Defer 1/10th */ |
520 | write_unlock_bh(&aarp_lock); |
521 | msleep(msecs: 100); |
522 | write_lock_bh(&aarp_lock); |
523 | |
524 | if (entry->status & ATIF_PROBE_FAIL) |
525 | break; |
526 | } |
527 | |
528 | if (entry->status & ATIF_PROBE_FAIL) { |
529 | entry->expires_at = jiffies - 1; /* free the entry */ |
530 | retval = -EADDRINUSE; /* return network full */ |
531 | } else { /* clear the probing flag */ |
532 | entry->status &= ~ATIF_PROBE; |
533 | retval = 1; |
534 | } |
535 | |
536 | write_unlock_bh(&aarp_lock); |
537 | out: |
538 | return retval; |
539 | } |
540 | |
541 | /* Send a DDP frame */ |
542 | int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb, |
543 | struct atalk_addr *sa, void *hwaddr) |
544 | { |
545 | static char ddp_eth_multicast[ETH_ALEN] = |
546 | { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; |
547 | int hash; |
548 | struct aarp_entry *a; |
549 | |
550 | skb_reset_network_header(skb); |
551 | |
552 | /* Check for LocalTalk first */ |
553 | if (dev->type == ARPHRD_LOCALTLK) { |
554 | struct atalk_addr *at = atalk_find_dev_addr(dev); |
555 | struct ddpehdr *ddp = (struct ddpehdr *)skb->data; |
556 | int ft = 2; |
557 | |
558 | /* |
559 | * Compressible ? |
560 | * |
561 | * IFF: src_net == dest_net == device_net |
562 | * (zero matches anything) |
563 | */ |
564 | |
565 | if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) && |
566 | (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) { |
567 | skb_pull(skb, len: sizeof(*ddp) - 4); |
568 | |
569 | /* |
570 | * The upper two remaining bytes are the port |
571 | * numbers we just happen to need. Now put the |
572 | * length in the lower two. |
573 | */ |
574 | *((__be16 *)skb->data) = htons(skb->len); |
575 | ft = 1; |
576 | } |
577 | /* |
578 | * Nice and easy. No AARP type protocols occur here so we can |
579 | * just shovel it out with a 3 byte LLAP header |
580 | */ |
581 | |
582 | skb_push(skb, len: 3); |
583 | skb->data[0] = sa->s_node; |
584 | skb->data[1] = at->s_node; |
585 | skb->data[2] = ft; |
586 | skb->dev = dev; |
587 | goto sendit; |
588 | } |
589 | |
590 | /* On a PPP link we neither compress nor aarp. */ |
591 | if (dev->type == ARPHRD_PPP) { |
592 | skb->protocol = htons(ETH_P_PPPTALK); |
593 | skb->dev = dev; |
594 | goto sendit; |
595 | } |
596 | |
597 | /* Non ELAP we cannot do. */ |
598 | if (dev->type != ARPHRD_ETHER) |
599 | goto free_it; |
600 | |
601 | skb->dev = dev; |
602 | skb->protocol = htons(ETH_P_ATALK); |
603 | hash = sa->s_node % (AARP_HASH_SIZE - 1); |
604 | |
605 | /* Do we have a resolved entry? */ |
606 | if (sa->s_node == ATADDR_BCAST) { |
607 | /* Send it */ |
608 | ddp_dl->request(ddp_dl, skb, ddp_eth_multicast); |
609 | goto sent; |
610 | } |
611 | |
612 | write_lock_bh(&aarp_lock); |
613 | a = __aarp_find_entry(list: resolved[hash], dev, sat: sa); |
614 | |
615 | if (a) { /* Return 1 and fill in the address */ |
616 | a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10); |
617 | ddp_dl->request(ddp_dl, skb, a->hwaddr); |
618 | write_unlock_bh(&aarp_lock); |
619 | goto sent; |
620 | } |
621 | |
622 | /* Do we have an unresolved entry: This is the less common path */ |
623 | a = __aarp_find_entry(list: unresolved[hash], dev, sat: sa); |
624 | if (a) { /* Queue onto the unresolved queue */ |
625 | skb_queue_tail(list: &a->packet_queue, newsk: skb); |
626 | goto out_unlock; |
627 | } |
628 | |
629 | /* Allocate a new entry */ |
630 | a = aarp_alloc(); |
631 | if (!a) { |
632 | /* Whoops slipped... good job it's an unreliable protocol 8) */ |
633 | write_unlock_bh(&aarp_lock); |
634 | goto free_it; |
635 | } |
636 | |
637 | /* Set up the queue */ |
638 | skb_queue_tail(list: &a->packet_queue, newsk: skb); |
639 | a->expires_at = jiffies + sysctl_aarp_resolve_time; |
640 | a->dev = dev; |
641 | a->next = unresolved[hash]; |
642 | a->target_addr = *sa; |
643 | a->xmit_count = 0; |
644 | unresolved[hash] = a; |
645 | unresolved_count++; |
646 | |
647 | /* Send an initial request for the address */ |
648 | __aarp_send_query(a); |
649 | |
650 | /* |
651 | * Switch to fast timer if needed (That is if this is the first |
652 | * unresolved entry to get added) |
653 | */ |
654 | |
655 | if (unresolved_count == 1) |
656 | mod_timer(timer: &aarp_timer, expires: jiffies + sysctl_aarp_tick_time); |
657 | |
658 | /* Now finally, it is safe to drop the lock. */ |
659 | out_unlock: |
660 | write_unlock_bh(&aarp_lock); |
661 | |
662 | /* Tell the ddp layer we have taken over for this frame. */ |
663 | goto sent; |
664 | |
665 | sendit: |
666 | if (skb->sk) |
667 | skb->priority = READ_ONCE(skb->sk->sk_priority); |
668 | if (dev_queue_xmit(skb)) |
669 | goto drop; |
670 | sent: |
671 | return NET_XMIT_SUCCESS; |
672 | free_it: |
673 | kfree_skb(skb); |
674 | drop: |
675 | return NET_XMIT_DROP; |
676 | } |
677 | EXPORT_SYMBOL(aarp_send_ddp); |
678 | |
679 | /* |
680 | * An entry in the aarp unresolved queue has become resolved. Send |
681 | * all the frames queued under it. |
682 | * |
683 | * Must run under aarp_lock. |
684 | */ |
685 | static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a, |
686 | int hash) |
687 | { |
688 | struct sk_buff *skb; |
689 | |
690 | while (*list) |
691 | if (*list == a) { |
692 | unresolved_count--; |
693 | *list = a->next; |
694 | |
695 | /* Move into the resolved list */ |
696 | a->next = resolved[hash]; |
697 | resolved[hash] = a; |
698 | |
699 | /* Kick frames off */ |
700 | while ((skb = skb_dequeue(list: &a->packet_queue)) != NULL) { |
701 | a->expires_at = jiffies + |
702 | sysctl_aarp_expiry_time * 10; |
703 | ddp_dl->request(ddp_dl, skb, a->hwaddr); |
704 | } |
705 | } else |
706 | list = &((*list)->next); |
707 | } |
708 | |
709 | /* |
710 | * This is called by the SNAP driver whenever we see an AARP SNAP |
711 | * frame. We currently only support Ethernet. |
712 | */ |
713 | static int aarp_rcv(struct sk_buff *skb, struct net_device *dev, |
714 | struct packet_type *pt, struct net_device *orig_dev) |
715 | { |
716 | struct elapaarp *ea = aarp_hdr(skb); |
717 | int hash, ret = 0; |
718 | __u16 function; |
719 | struct aarp_entry *a; |
720 | struct atalk_addr sa, *ma, da; |
721 | struct atalk_iface *ifa; |
722 | |
723 | if (!net_eq(net1: dev_net(dev), net2: &init_net)) |
724 | goto out0; |
725 | |
726 | /* We only do Ethernet SNAP AARP. */ |
727 | if (dev->type != ARPHRD_ETHER) |
728 | goto out0; |
729 | |
730 | /* Frame size ok? */ |
731 | if (!skb_pull(skb, len: sizeof(*ea))) |
732 | goto out0; |
733 | |
734 | function = ntohs(ea->function); |
735 | |
736 | /* Sanity check fields. */ |
737 | if (function < AARP_REQUEST || function > AARP_PROBE || |
738 | ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN || |
739 | ea->pa_src_zero || ea->pa_dst_zero) |
740 | goto out0; |
741 | |
742 | /* Looks good. */ |
743 | hash = ea->pa_src_node % (AARP_HASH_SIZE - 1); |
744 | |
745 | /* Build an address. */ |
746 | sa.s_node = ea->pa_src_node; |
747 | sa.s_net = ea->pa_src_net; |
748 | |
749 | /* Process the packet. Check for replies of me. */ |
750 | ifa = atalk_find_dev(dev); |
751 | if (!ifa) |
752 | goto out1; |
753 | |
754 | if (ifa->status & ATIF_PROBE && |
755 | ifa->address.s_node == ea->pa_dst_node && |
756 | ifa->address.s_net == ea->pa_dst_net) { |
757 | ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */ |
758 | goto out1; |
759 | } |
760 | |
761 | /* Check for replies of proxy AARP entries */ |
762 | da.s_node = ea->pa_dst_node; |
763 | da.s_net = ea->pa_dst_net; |
764 | |
765 | write_lock_bh(&aarp_lock); |
766 | a = __aarp_find_entry(list: proxies[hash], dev, sat: &da); |
767 | |
768 | if (a && a->status & ATIF_PROBE) { |
769 | a->status |= ATIF_PROBE_FAIL; |
770 | /* |
771 | * we do not respond to probe or request packets of |
772 | * this address while we are probing this address |
773 | */ |
774 | goto unlock; |
775 | } |
776 | |
777 | switch (function) { |
778 | case AARP_REPLY: |
779 | if (!unresolved_count) /* Speed up */ |
780 | break; |
781 | |
782 | /* Find the entry. */ |
783 | a = __aarp_find_entry(list: unresolved[hash], dev, sat: &sa); |
784 | if (!a || dev != a->dev) |
785 | break; |
786 | |
787 | /* We can fill one in - this is good. */ |
788 | ether_addr_copy(dst: a->hwaddr, src: ea->hw_src); |
789 | __aarp_resolved(list: &unresolved[hash], a, hash); |
790 | if (!unresolved_count) |
791 | mod_timer(timer: &aarp_timer, |
792 | expires: jiffies + sysctl_aarp_expiry_time); |
793 | break; |
794 | |
795 | case AARP_REQUEST: |
796 | case AARP_PROBE: |
797 | |
798 | /* |
799 | * If it is my address set ma to my address and reply. |
800 | * We can treat probe and request the same. Probe |
801 | * simply means we shouldn't cache the querying host, |
802 | * as in a probe they are proposing an address not |
803 | * using one. |
804 | * |
805 | * Support for proxy-AARP added. We check if the |
806 | * address is one of our proxies before we toss the |
807 | * packet out. |
808 | */ |
809 | |
810 | sa.s_node = ea->pa_dst_node; |
811 | sa.s_net = ea->pa_dst_net; |
812 | |
813 | /* See if we have a matching proxy. */ |
814 | ma = __aarp_proxy_find(dev, sa: &sa); |
815 | if (!ma) |
816 | ma = &ifa->address; |
817 | else { /* We need to make a copy of the entry. */ |
818 | da.s_node = sa.s_node; |
819 | da.s_net = sa.s_net; |
820 | ma = &da; |
821 | } |
822 | |
823 | if (function == AARP_PROBE) { |
824 | /* |
825 | * A probe implies someone trying to get an |
826 | * address. So as a precaution flush any |
827 | * entries we have for this address. |
828 | */ |
829 | a = __aarp_find_entry(list: resolved[sa.s_node % |
830 | (AARP_HASH_SIZE - 1)], |
831 | dev: skb->dev, sat: &sa); |
832 | |
833 | /* |
834 | * Make it expire next tick - that avoids us |
835 | * getting into a probe/flush/learn/probe/ |
836 | * flush/learn cycle during probing of a slow |
837 | * to respond host addr. |
838 | */ |
839 | if (a) { |
840 | a->expires_at = jiffies - 1; |
841 | mod_timer(timer: &aarp_timer, expires: jiffies + |
842 | sysctl_aarp_tick_time); |
843 | } |
844 | } |
845 | |
846 | if (sa.s_node != ma->s_node) |
847 | break; |
848 | |
849 | if (sa.s_net && ma->s_net && sa.s_net != ma->s_net) |
850 | break; |
851 | |
852 | sa.s_node = ea->pa_src_node; |
853 | sa.s_net = ea->pa_src_net; |
854 | |
855 | /* aarp_my_address has found the address to use for us. |
856 | */ |
857 | aarp_send_reply(dev, us: ma, them: &sa, sha: ea->hw_src); |
858 | break; |
859 | } |
860 | |
861 | unlock: |
862 | write_unlock_bh(&aarp_lock); |
863 | out1: |
864 | ret = 1; |
865 | out0: |
866 | kfree_skb(skb); |
867 | return ret; |
868 | } |
869 | |
870 | static struct notifier_block aarp_notifier = { |
871 | .notifier_call = aarp_device_event, |
872 | }; |
873 | |
874 | static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 }; |
875 | |
876 | int __init aarp_proto_init(void) |
877 | { |
878 | int rc; |
879 | |
880 | aarp_dl = register_snap_client(desc: aarp_snap_id, rcvfunc: aarp_rcv); |
881 | if (!aarp_dl) { |
882 | printk(KERN_CRIT "Unable to register AARP with SNAP.\n" ); |
883 | return -ENOMEM; |
884 | } |
885 | timer_setup(&aarp_timer, aarp_expire_timeout, 0); |
886 | aarp_timer.expires = jiffies + sysctl_aarp_expiry_time; |
887 | add_timer(timer: &aarp_timer); |
888 | rc = register_netdevice_notifier(nb: &aarp_notifier); |
889 | if (rc) { |
890 | del_timer_sync(timer: &aarp_timer); |
891 | unregister_snap_client(proto: aarp_dl); |
892 | } |
893 | return rc; |
894 | } |
895 | |
896 | /* Remove the AARP entries associated with a device. */ |
897 | void aarp_device_down(struct net_device *dev) |
898 | { |
899 | int ct; |
900 | |
901 | write_lock_bh(&aarp_lock); |
902 | |
903 | for (ct = 0; ct < AARP_HASH_SIZE; ct++) { |
904 | __aarp_expire_device(n: &resolved[ct], dev); |
905 | __aarp_expire_device(n: &unresolved[ct], dev); |
906 | __aarp_expire_device(n: &proxies[ct], dev); |
907 | } |
908 | |
909 | write_unlock_bh(&aarp_lock); |
910 | } |
911 | |
912 | #ifdef CONFIG_PROC_FS |
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, fmt: "%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(m: seq, |
1009 | s: "Address Interface Hardware Address" |
1010 | " Expires LastSend Retry Status\n" ); |
1011 | else { |
1012 | seq_printf(m: seq, fmt: "%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(m: seq, fmt: "%pM" , entry->hwaddr); |
1017 | seq_printf(m: seq, fmt: " %8s" , |
1018 | dt2str(ticks: (long)entry->expires_at - (long)now)); |
1019 | if (iter->table == unresolved) |
1020 | seq_printf(m: seq, fmt: " %8s %6hu" , |
1021 | dt2str(ticks: now - entry->last_sent), |
1022 | entry->xmit_count); |
1023 | else |
1024 | seq_puts(m: seq, s: " " ); |
1025 | seq_printf(m: seq, fmt: " %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 | 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 | #endif |
1041 | |
1042 | /* General module cleanup. Called from cleanup_module() in ddp.c. */ |
1043 | void aarp_cleanup_module(void) |
1044 | { |
1045 | del_timer_sync(timer: &aarp_timer); |
1046 | unregister_netdevice_notifier(nb: &aarp_notifier); |
1047 | unregister_snap_client(proto: aarp_dl); |
1048 | aarp_purge(); |
1049 | } |
1050 | |