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