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