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 (event == NETDEV_DOWN) { 337 write_lock_bh(&aarp_lock); 338 339 for (ct = 0; ct < AARP_HASH_SIZE; ct++) { 340 __aarp_expire_device(&resolved[ct], dev); 341 __aarp_expire_device(&unresolved[ct], dev); 342 __aarp_expire_device(&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(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(&resolved[ct]); 370 __aarp_expire_all(&unresolved[ct]); 371 __aarp_expire_all(&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(sizeof(*a), GFP_ATOMIC); 383 384 if (a) 385 skb_queue_head_init(&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(proxies[hash], dev, 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(proxies[hash], dev, 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; 443 444 sa->sat_addr.s_node = iface->address.s_node; 445 sa->sat_addr.s_net = ntohs(iface->address.s_net); 446 447 /* We pass the Net:Node to the drivers/cards by a Device ioctl. */ 448 if (!(iface->dev->do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) { 449 (void)iface->dev->do_ioctl(iface->dev, &atreq, SIOCGIFADDR); 450 if (iface->address.s_net != htons(sa->sat_addr.s_net) || 451 iface->address.s_node != sa->sat_addr.s_node) 452 iface->status |= ATIF_PROBE_FAIL; 453 454 iface->address.s_net = htons(sa->sat_addr.s_net); 455 iface->address.s_node = sa->sat_addr.s_node; 456 } 457 } 458 459 460 void aarp_probe_network(struct atalk_iface *atif) 461 { 462 if (atif->dev->type == ARPHRD_LOCALTLK || 463 atif->dev->type == ARPHRD_PPP) 464 aarp_send_probe_phase1(atif); 465 else { 466 unsigned int count; 467 468 for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { 469 aarp_send_probe(atif->dev, &atif->address); 470 471 /* Defer 1/10th */ 472 msleep(100); 473 474 if (atif->status & ATIF_PROBE_FAIL) 475 break; 476 } 477 } 478 } 479 480 int aarp_proxy_probe_network(struct atalk_iface *atif, struct atalk_addr *sa) 481 { 482 int hash, retval = -EPROTONOSUPPORT; 483 struct aarp_entry *entry; 484 unsigned int count; 485 486 /* 487 * we don't currently support LocalTalk or PPP for proxy AARP; 488 * if someone wants to try and add it, have fun 489 */ 490 if (atif->dev->type == ARPHRD_LOCALTLK || 491 atif->dev->type == ARPHRD_PPP) 492 goto out; 493 494 /* 495 * create a new AARP entry with the flags set to be published -- 496 * we need this one to hang around even if it's in use 497 */ 498 entry = aarp_alloc(); 499 retval = -ENOMEM; 500 if (!entry) 501 goto out; 502 503 entry->expires_at = -1; 504 entry->status = ATIF_PROBE; 505 entry->target_addr.s_node = sa->s_node; 506 entry->target_addr.s_net = sa->s_net; 507 entry->dev = atif->dev; 508 509 write_lock_bh(&aarp_lock); 510 511 hash = sa->s_node % (AARP_HASH_SIZE - 1); 512 entry->next = proxies[hash]; 513 proxies[hash] = entry; 514 515 for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { 516 aarp_send_probe(atif->dev, sa); 517 518 /* Defer 1/10th */ 519 write_unlock_bh(&aarp_lock); 520 msleep(100); 521 write_lock_bh(&aarp_lock); 522 523 if (entry->status & ATIF_PROBE_FAIL) 524 break; 525 } 526 527 if (entry->status & ATIF_PROBE_FAIL) { 528 entry->expires_at = jiffies - 1; /* free the entry */ 529 retval = -EADDRINUSE; /* return network full */ 530 } else { /* clear the probing flag */ 531 entry->status &= ~ATIF_PROBE; 532 retval = 1; 533 } 534 535 write_unlock_bh(&aarp_lock); 536 out: 537 return retval; 538 } 539 540 /* Send a DDP frame */ 541 int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb, 542 struct atalk_addr *sa, void *hwaddr) 543 { 544 static char ddp_eth_multicast[ETH_ALEN] = 545 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; 546 int hash; 547 struct aarp_entry *a; 548 549 skb_reset_network_header(skb); 550 551 /* Check for LocalTalk first */ 552 if (dev->type == ARPHRD_LOCALTLK) { 553 struct atalk_addr *at = atalk_find_dev_addr(dev); 554 struct ddpehdr *ddp = (struct ddpehdr *)skb->data; 555 int ft = 2; 556 557 /* 558 * Compressible ? 559 * 560 * IFF: src_net == dest_net == device_net 561 * (zero matches anything) 562 */ 563 564 if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) && 565 (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) { 566 skb_pull(skb, sizeof(*ddp) - 4); 567 568 /* 569 * The upper two remaining bytes are the port 570 * numbers we just happen to need. Now put the 571 * length in the lower two. 572 */ 573 *((__be16 *)skb->data) = htons(skb->len); 574 ft = 1; 575 } 576 /* 577 * Nice and easy. No AARP type protocols occur here so we can 578 * just shovel it out with a 3 byte LLAP header 579 */ 580 581 skb_push(skb, 3); 582 skb->data[0] = sa->s_node; 583 skb->data[1] = at->s_node; 584 skb->data[2] = ft; 585 skb->dev = dev; 586 goto sendit; 587 } 588 589 /* On a PPP link we neither compress nor aarp. */ 590 if (dev->type == ARPHRD_PPP) { 591 skb->protocol = htons(ETH_P_PPPTALK); 592 skb->dev = dev; 593 goto sendit; 594 } 595 596 /* Non ELAP we cannot do. */ 597 if (dev->type != ARPHRD_ETHER) 598 return -1; 599 600 skb->dev = dev; 601 skb->protocol = htons(ETH_P_ATALK); 602 hash = sa->s_node % (AARP_HASH_SIZE - 1); 603 604 /* Do we have a resolved entry? */ 605 if (sa->s_node == ATADDR_BCAST) { 606 /* Send it */ 607 ddp_dl->request(ddp_dl, skb, ddp_eth_multicast); 608 goto sent; 609 } 610 611 write_lock_bh(&aarp_lock); 612 a = __aarp_find_entry(resolved[hash], dev, sa); 613 614 if (a) { /* Return 1 and fill in the address */ 615 a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10); 616 ddp_dl->request(ddp_dl, skb, a->hwaddr); 617 write_unlock_bh(&aarp_lock); 618 goto sent; 619 } 620 621 /* Do we have an unresolved entry: This is the less common path */ 622 a = __aarp_find_entry(unresolved[hash], dev, sa); 623 if (a) { /* Queue onto the unresolved queue */ 624 skb_queue_tail(&a->packet_queue, skb); 625 goto out_unlock; 626 } 627 628 /* Allocate a new entry */ 629 a = aarp_alloc(); 630 if (!a) { 631 /* Whoops slipped... good job it's an unreliable protocol 8) */ 632 write_unlock_bh(&aarp_lock); 633 return -1; 634 } 635 636 /* Set up the queue */ 637 skb_queue_tail(&a->packet_queue, skb); 638 a->expires_at = jiffies + sysctl_aarp_resolve_time; 639 a->dev = dev; 640 a->next = unresolved[hash]; 641 a->target_addr = *sa; 642 a->xmit_count = 0; 643 unresolved[hash] = a; 644 unresolved_count++; 645 646 /* Send an initial request for the address */ 647 __aarp_send_query(a); 648 649 /* 650 * Switch to fast timer if needed (That is if this is the first 651 * unresolved entry to get added) 652 */ 653 654 if (unresolved_count == 1) 655 mod_timer(&aarp_timer, jiffies + sysctl_aarp_tick_time); 656 657 /* Now finally, it is safe to drop the lock. */ 658 out_unlock: 659 write_unlock_bh(&aarp_lock); 660 661 /* Tell the ddp layer we have taken over for this frame. */ 662 return 0; 663 664 sendit: 665 if (skb->sk) 666 skb->priority = skb->sk->sk_priority; 667 dev_queue_xmit(skb); 668 sent: 669 return 1; 670 } 671 672 /* 673 * An entry in the aarp unresolved queue has become resolved. Send 674 * all the frames queued under it. 675 * 676 * Must run under aarp_lock. 677 */ 678 static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a, 679 int hash) 680 { 681 struct sk_buff *skb; 682 683 while (*list) 684 if (*list == a) { 685 unresolved_count--; 686 *list = a->next; 687 688 /* Move into the resolved list */ 689 a->next = resolved[hash]; 690 resolved[hash] = a; 691 692 /* Kick frames off */ 693 while ((skb = skb_dequeue(&a->packet_queue)) != NULL) { 694 a->expires_at = jiffies + 695 sysctl_aarp_expiry_time * 10; 696 ddp_dl->request(ddp_dl, skb, a->hwaddr); 697 } 698 } else 699 list = &((*list)->next); 700 } 701 702 /* 703 * This is called by the SNAP driver whenever we see an AARP SNAP 704 * frame. We currently only support Ethernet. 705 */ 706 static int aarp_rcv(struct sk_buff *skb, struct net_device *dev, 707 struct packet_type *pt, struct net_device *orig_dev) 708 { 709 struct elapaarp *ea = aarp_hdr(skb); 710 int hash, ret = 0; 711 __u16 function; 712 struct aarp_entry *a; 713 struct atalk_addr sa, *ma, da; 714 struct atalk_iface *ifa; 715 716 if (dev->nd_net != &init_net) 717 goto out0; 718 719 /* We only do Ethernet SNAP AARP. */ 720 if (dev->type != ARPHRD_ETHER) 721 goto out0; 722 723 /* Frame size ok? */ 724 if (!skb_pull(skb, sizeof(*ea))) 725 goto out0; 726 727 function = ntohs(ea->function); 728 729 /* Sanity check fields. */ 730 if (function < AARP_REQUEST || function > AARP_PROBE || 731 ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN || 732 ea->pa_src_zero || ea->pa_dst_zero) 733 goto out0; 734 735 /* Looks good. */ 736 hash = ea->pa_src_node % (AARP_HASH_SIZE - 1); 737 738 /* Build an address. */ 739 sa.s_node = ea->pa_src_node; 740 sa.s_net = ea->pa_src_net; 741 742 /* Process the packet. Check for replies of me. */ 743 ifa = atalk_find_dev(dev); 744 if (!ifa) 745 goto out1; 746 747 if (ifa->status & ATIF_PROBE && 748 ifa->address.s_node == ea->pa_dst_node && 749 ifa->address.s_net == ea->pa_dst_net) { 750 ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */ 751 goto out1; 752 } 753 754 /* Check for replies of proxy AARP entries */ 755 da.s_node = ea->pa_dst_node; 756 da.s_net = ea->pa_dst_net; 757 758 write_lock_bh(&aarp_lock); 759 a = __aarp_find_entry(proxies[hash], dev, &da); 760 761 if (a && a->status & ATIF_PROBE) { 762 a->status |= ATIF_PROBE_FAIL; 763 /* 764 * we do not respond to probe or request packets for 765 * this address while we are probing this address 766 */ 767 goto unlock; 768 } 769 770 switch (function) { 771 case AARP_REPLY: 772 if (!unresolved_count) /* Speed up */ 773 break; 774 775 /* Find the entry. */ 776 a = __aarp_find_entry(unresolved[hash], dev, &sa); 777 if (!a || dev != a->dev) 778 break; 779 780 /* We can fill one in - this is good. */ 781 memcpy(a->hwaddr, ea->hw_src, ETH_ALEN); 782 __aarp_resolved(&unresolved[hash], a, hash); 783 if (!unresolved_count) 784 mod_timer(&aarp_timer, 785 jiffies + sysctl_aarp_expiry_time); 786 break; 787 788 case AARP_REQUEST: 789 case AARP_PROBE: 790 791 /* 792 * If it is my address set ma to my address and reply. 793 * We can treat probe and request the same. Probe 794 * simply means we shouldn't cache the querying host, 795 * as in a probe they are proposing an address not 796 * using one. 797 * 798 * Support for proxy-AARP added. We check if the 799 * address is one of our proxies before we toss the 800 * packet out. 801 */ 802 803 sa.s_node = ea->pa_dst_node; 804 sa.s_net = ea->pa_dst_net; 805 806 /* See if we have a matching proxy. */ 807 ma = __aarp_proxy_find(dev, &sa); 808 if (!ma) 809 ma = &ifa->address; 810 else { /* We need to make a copy of the entry. */ 811 da.s_node = sa.s_node; 812 da.s_net = da.s_net; 813 ma = &da; 814 } 815 816 if (function == AARP_PROBE) { 817 /* 818 * A probe implies someone trying to get an 819 * address. So as a precaution flush any 820 * entries we have for this address. 821 */ 822 struct aarp_entry *a; 823 824 a = __aarp_find_entry(resolved[sa.s_node % 825 (AARP_HASH_SIZE - 1)], 826 skb->dev, &sa); 827 828 /* 829 * Make it expire next tick - that avoids us 830 * getting into a probe/flush/learn/probe/ 831 * flush/learn cycle during probing of a slow 832 * to respond host addr. 833 */ 834 if (a) { 835 a->expires_at = jiffies - 1; 836 mod_timer(&aarp_timer, jiffies + 837 sysctl_aarp_tick_time); 838 } 839 } 840 841 if (sa.s_node != ma->s_node) 842 break; 843 844 if (sa.s_net && ma->s_net && sa.s_net != ma->s_net) 845 break; 846 847 sa.s_node = ea->pa_src_node; 848 sa.s_net = ea->pa_src_net; 849 850 /* aarp_my_address has found the address to use for us. 851 */ 852 aarp_send_reply(dev, ma, &sa, ea->hw_src); 853 break; 854 } 855 856 unlock: 857 write_unlock_bh(&aarp_lock); 858 out1: 859 ret = 1; 860 out0: 861 kfree_skb(skb); 862 return ret; 863 } 864 865 static struct notifier_block aarp_notifier = { 866 .notifier_call = aarp_device_event, 867 }; 868 869 static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 }; 870 871 void __init aarp_proto_init(void) 872 { 873 aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv); 874 if (!aarp_dl) 875 printk(KERN_CRIT "Unable to register AARP with SNAP.\n"); 876 init_timer(&aarp_timer); 877 aarp_timer.function = aarp_expire_timeout; 878 aarp_timer.data = 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 { 946 struct aarp_iter_state *iter = seq->private; 947 948 read_lock_bh(&aarp_lock); 949 iter->table = resolved; 950 iter->bucket = 0; 951 952 return *pos ? iter_next(iter, pos) : SEQ_START_TOKEN; 953 } 954 955 static void *aarp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 956 { 957 struct aarp_entry *entry = v; 958 struct aarp_iter_state *iter = seq->private; 959 960 ++*pos; 961 962 /* first line after header */ 963 if (v == SEQ_START_TOKEN) 964 entry = iter_next(iter, NULL); 965 966 /* next entry in current bucket */ 967 else if (entry->next) 968 entry = entry->next; 969 970 /* next bucket or table */ 971 else { 972 ++iter->bucket; 973 entry = iter_next(iter, NULL); 974 } 975 return entry; 976 } 977 978 static void aarp_seq_stop(struct seq_file *seq, void *v) 979 { 980 read_unlock_bh(&aarp_lock); 981 } 982 983 static const char *dt2str(unsigned long ticks) 984 { 985 static char buf[32]; 986 987 sprintf(buf, "%ld.%02ld", ticks / HZ, ((ticks % HZ) * 100 ) / HZ); 988 989 return buf; 990 } 991 992 static int aarp_seq_show(struct seq_file *seq, void *v) 993 { 994 struct aarp_iter_state *iter = seq->private; 995 struct aarp_entry *entry = v; 996 unsigned long now = jiffies; 997 998 if (v == SEQ_START_TOKEN) 999 seq_puts(seq, 1000 "Address Interface Hardware Address" 1001 " Expires LastSend Retry Status\n"); 1002 else { 1003 seq_printf(seq, "%04X:%02X %-12s", 1004 ntohs(entry->target_addr.s_net), 1005 (unsigned int) entry->target_addr.s_node, 1006 entry->dev ? entry->dev->name : "????"); 1007 seq_printf(seq, "%02X:%02X:%02X:%02X:%02X:%02X", 1008 entry->hwaddr[0] & 0xFF, 1009 entry->hwaddr[1] & 0xFF, 1010 entry->hwaddr[2] & 0xFF, 1011 entry->hwaddr[3] & 0xFF, 1012 entry->hwaddr[4] & 0xFF, 1013 entry->hwaddr[5] & 0xFF); 1014 seq_printf(seq, " %8s", 1015 dt2str((long)entry->expires_at - (long)now)); 1016 if (iter->table == unresolved) 1017 seq_printf(seq, " %8s %6hu", 1018 dt2str(now - entry->last_sent), 1019 entry->xmit_count); 1020 else 1021 seq_puts(seq, " "); 1022 seq_printf(seq, " %s\n", 1023 (iter->table == resolved) ? "resolved" 1024 : (iter->table == unresolved) ? "unresolved" 1025 : (iter->table == proxies) ? "proxies" 1026 : "unknown"); 1027 } 1028 return 0; 1029 } 1030 1031 static const struct seq_operations aarp_seq_ops = { 1032 .start = aarp_seq_start, 1033 .next = aarp_seq_next, 1034 .stop = aarp_seq_stop, 1035 .show = aarp_seq_show, 1036 }; 1037 1038 static int aarp_seq_open(struct inode *inode, struct file *file) 1039 { 1040 struct seq_file *seq; 1041 int rc = -ENOMEM; 1042 struct aarp_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL); 1043 1044 if (!s) 1045 goto out; 1046 1047 rc = seq_open(file, &aarp_seq_ops); 1048 if (rc) 1049 goto out_kfree; 1050 1051 seq = file->private_data; 1052 seq->private = s; 1053 memset(s, 0, sizeof(*s)); 1054 out: 1055 return rc; 1056 out_kfree: 1057 kfree(s); 1058 goto out; 1059 } 1060 1061 const struct file_operations atalk_seq_arp_fops = { 1062 .owner = THIS_MODULE, 1063 .open = aarp_seq_open, 1064 .read = seq_read, 1065 .llseek = seq_lseek, 1066 .release = seq_release_private, 1067 }; 1068 #endif 1069 1070 /* General module cleanup. Called from cleanup_module() in ddp.c. */ 1071 void aarp_cleanup_module(void) 1072 { 1073 del_timer_sync(&aarp_timer); 1074 unregister_netdevice_notifier(&aarp_notifier); 1075 unregister_snap_client(aarp_dl); 1076 aarp_purge(); 1077 } 1078