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