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/config.h> 33 #include <linux/if_arp.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->nh.raw = skb->h.raw = skb_put(skb, sizeof(*eah)); 123 skb->protocol = htons(ETH_P_ATALK); 124 skb->dev = dev; 125 eah = aarp_hdr(skb); 126 127 /* Set up the ARP */ 128 eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); 129 eah->pa_type = htons(ETH_P_ATALK); 130 eah->hw_len = ETH_ALEN; 131 eah->pa_len = AARP_PA_ALEN; 132 eah->function = htons(AARP_REQUEST); 133 134 memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN); 135 136 eah->pa_src_zero = 0; 137 eah->pa_src_net = sat->s_net; 138 eah->pa_src_node = sat->s_node; 139 140 memset(eah->hw_dst, '\0', ETH_ALEN); 141 142 eah->pa_dst_zero = 0; 143 eah->pa_dst_net = a->target_addr.s_net; 144 eah->pa_dst_node = a->target_addr.s_node; 145 146 /* Send it */ 147 aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); 148 /* Update the sending count */ 149 a->xmit_count++; 150 a->last_sent = jiffies; 151 } 152 153 /* This runs under aarp_lock and in softint context, so only atomic memory 154 * allocations can be used. */ 155 static void aarp_send_reply(struct net_device *dev, struct atalk_addr *us, 156 struct atalk_addr *them, unsigned char *sha) 157 { 158 struct elapaarp *eah; 159 int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; 160 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); 161 162 if (!skb) 163 return; 164 165 /* Set up the buffer */ 166 skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length); 167 skb->nh.raw = skb->h.raw = skb_put(skb, sizeof(*eah)); 168 skb->protocol = htons(ETH_P_ATALK); 169 skb->dev = dev; 170 eah = aarp_hdr(skb); 171 172 /* Set up the ARP */ 173 eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); 174 eah->pa_type = htons(ETH_P_ATALK); 175 eah->hw_len = ETH_ALEN; 176 eah->pa_len = AARP_PA_ALEN; 177 eah->function = htons(AARP_REPLY); 178 179 memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN); 180 181 eah->pa_src_zero = 0; 182 eah->pa_src_net = us->s_net; 183 eah->pa_src_node = us->s_node; 184 185 if (!sha) 186 memset(eah->hw_dst, '\0', ETH_ALEN); 187 else 188 memcpy(eah->hw_dst, sha, ETH_ALEN); 189 190 eah->pa_dst_zero = 0; 191 eah->pa_dst_net = them->s_net; 192 eah->pa_dst_node = them->s_node; 193 194 /* Send it */ 195 aarp_dl->request(aarp_dl, skb, sha); 196 } 197 198 /* 199 * Send probe frames. Called from aarp_probe_network and 200 * aarp_proxy_probe_network. 201 */ 202 203 static void aarp_send_probe(struct net_device *dev, struct atalk_addr *us) 204 { 205 struct elapaarp *eah; 206 int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; 207 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); 208 static unsigned char aarp_eth_multicast[ETH_ALEN] = 209 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; 210 211 if (!skb) 212 return; 213 214 /* Set up the buffer */ 215 skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length); 216 skb->nh.raw = skb->h.raw = skb_put(skb, sizeof(*eah)); 217 skb->protocol = htons(ETH_P_ATALK); 218 skb->dev = dev; 219 eah = aarp_hdr(skb); 220 221 /* Set up the ARP */ 222 eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); 223 eah->pa_type = htons(ETH_P_ATALK); 224 eah->hw_len = ETH_ALEN; 225 eah->pa_len = AARP_PA_ALEN; 226 eah->function = htons(AARP_PROBE); 227 228 memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN); 229 230 eah->pa_src_zero = 0; 231 eah->pa_src_net = us->s_net; 232 eah->pa_src_node = us->s_node; 233 234 memset(eah->hw_dst, '\0', ETH_ALEN); 235 236 eah->pa_dst_zero = 0; 237 eah->pa_dst_net = us->s_net; 238 eah->pa_dst_node = us->s_node; 239 240 /* Send it */ 241 aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); 242 } 243 244 /* 245 * Handle an aarp timer expire 246 * 247 * Must run under the aarp_lock. 248 */ 249 250 static void __aarp_expire_timer(struct aarp_entry **n) 251 { 252 struct aarp_entry *t; 253 254 while (*n) 255 /* Expired ? */ 256 if (time_after(jiffies, (*n)->expires_at)) { 257 t = *n; 258 *n = (*n)->next; 259 __aarp_expire(t); 260 } else 261 n = &((*n)->next); 262 } 263 264 /* 265 * Kick all pending requests 5 times a second. 266 * 267 * Must run under the aarp_lock. 268 */ 269 static void __aarp_kick(struct aarp_entry **n) 270 { 271 struct aarp_entry *t; 272 273 while (*n) 274 /* Expired: if this will be the 11th tx, we delete instead. */ 275 if ((*n)->xmit_count >= sysctl_aarp_retransmit_limit) { 276 t = *n; 277 *n = (*n)->next; 278 __aarp_expire(t); 279 } else { 280 __aarp_send_query(*n); 281 n = &((*n)->next); 282 } 283 } 284 285 /* 286 * A device has gone down. Take all entries referring to the device 287 * and remove them. 288 * 289 * Must run under the aarp_lock. 290 */ 291 static void __aarp_expire_device(struct aarp_entry **n, struct net_device *dev) 292 { 293 struct aarp_entry *t; 294 295 while (*n) 296 if ((*n)->dev == dev) { 297 t = *n; 298 *n = (*n)->next; 299 __aarp_expire(t); 300 } else 301 n = &((*n)->next); 302 } 303 304 /* Handle the timer event */ 305 static void aarp_expire_timeout(unsigned long unused) 306 { 307 int ct; 308 309 write_lock_bh(&aarp_lock); 310 311 for (ct = 0; ct < AARP_HASH_SIZE; ct++) { 312 __aarp_expire_timer(&resolved[ct]); 313 __aarp_kick(&unresolved[ct]); 314 __aarp_expire_timer(&unresolved[ct]); 315 __aarp_expire_timer(&proxies[ct]); 316 } 317 318 write_unlock_bh(&aarp_lock); 319 mod_timer(&aarp_timer, jiffies + 320 (unresolved_count ? sysctl_aarp_tick_time : 321 sysctl_aarp_expiry_time)); 322 } 323 324 /* Network device notifier chain handler. */ 325 static int aarp_device_event(struct notifier_block *this, unsigned long event, 326 void *ptr) 327 { 328 int ct; 329 330 if (event == NETDEV_DOWN) { 331 write_lock_bh(&aarp_lock); 332 333 for (ct = 0; ct < AARP_HASH_SIZE; ct++) { 334 __aarp_expire_device(&resolved[ct], ptr); 335 __aarp_expire_device(&unresolved[ct], ptr); 336 __aarp_expire_device(&proxies[ct], ptr); 337 } 338 339 write_unlock_bh(&aarp_lock); 340 } 341 return NOTIFY_DONE; 342 } 343 344 /* Expire all entries in a hash chain */ 345 static void __aarp_expire_all(struct aarp_entry **n) 346 { 347 struct aarp_entry *t; 348 349 while (*n) { 350 t = *n; 351 *n = (*n)->next; 352 __aarp_expire(t); 353 } 354 } 355 356 /* Cleanup all hash chains -- module unloading */ 357 static void aarp_purge(void) 358 { 359 int ct; 360 361 write_lock_bh(&aarp_lock); 362 for (ct = 0; ct < AARP_HASH_SIZE; ct++) { 363 __aarp_expire_all(&resolved[ct]); 364 __aarp_expire_all(&unresolved[ct]); 365 __aarp_expire_all(&proxies[ct]); 366 } 367 write_unlock_bh(&aarp_lock); 368 } 369 370 /* 371 * Create a new aarp entry. This must use GFP_ATOMIC because it 372 * runs while holding spinlocks. 373 */ 374 static struct aarp_entry *aarp_alloc(void) 375 { 376 struct aarp_entry *a = kmalloc(sizeof(*a), GFP_ATOMIC); 377 378 if (a) 379 skb_queue_head_init(&a->packet_queue); 380 return a; 381 } 382 383 /* 384 * Find an entry. We might return an expired but not yet purged entry. We 385 * don't care as it will do no harm. 386 * 387 * This must run under the aarp_lock. 388 */ 389 static struct aarp_entry *__aarp_find_entry(struct aarp_entry *list, 390 struct net_device *dev, 391 struct atalk_addr *sat) 392 { 393 while (list) { 394 if (list->target_addr.s_net == sat->s_net && 395 list->target_addr.s_node == sat->s_node && 396 list->dev == dev) 397 break; 398 list = list->next; 399 } 400 401 return list; 402 } 403 404 /* Called from the DDP code, and thus must be exported. */ 405 void aarp_proxy_remove(struct net_device *dev, struct atalk_addr *sa) 406 { 407 int hash = sa->s_node % (AARP_HASH_SIZE - 1); 408 struct aarp_entry *a; 409 410 write_lock_bh(&aarp_lock); 411 412 a = __aarp_find_entry(proxies[hash], dev, sa); 413 if (a) 414 a->expires_at = jiffies - 1; 415 416 write_unlock_bh(&aarp_lock); 417 } 418 419 /* This must run under aarp_lock. */ 420 static struct atalk_addr *__aarp_proxy_find(struct net_device *dev, 421 struct atalk_addr *sa) 422 { 423 int hash = sa->s_node % (AARP_HASH_SIZE - 1); 424 struct aarp_entry *a = __aarp_find_entry(proxies[hash], dev, sa); 425 426 return a ? sa : NULL; 427 } 428 429 /* 430 * Probe a Phase 1 device or a device that requires its Net:Node to 431 * be set via an ioctl. 432 */ 433 static void aarp_send_probe_phase1(struct atalk_iface *iface) 434 { 435 struct ifreq atreq; 436 struct sockaddr_at *sa = (struct sockaddr_at *)&atreq.ifr_addr; 437 438 sa->sat_addr.s_node = iface->address.s_node; 439 sa->sat_addr.s_net = ntohs(iface->address.s_net); 440 441 /* We pass the Net:Node to the drivers/cards by a Device ioctl. */ 442 if (!(iface->dev->do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) { 443 (void)iface->dev->do_ioctl(iface->dev, &atreq, SIOCGIFADDR); 444 if (iface->address.s_net != htons(sa->sat_addr.s_net) || 445 iface->address.s_node != sa->sat_addr.s_node) 446 iface->status |= ATIF_PROBE_FAIL; 447 448 iface->address.s_net = htons(sa->sat_addr.s_net); 449 iface->address.s_node = sa->sat_addr.s_node; 450 } 451 } 452 453 454 void aarp_probe_network(struct atalk_iface *atif) 455 { 456 if (atif->dev->type == ARPHRD_LOCALTLK || 457 atif->dev->type == ARPHRD_PPP) 458 aarp_send_probe_phase1(atif); 459 else { 460 unsigned int count; 461 462 for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { 463 aarp_send_probe(atif->dev, &atif->address); 464 465 /* Defer 1/10th */ 466 msleep(100); 467 468 if (atif->status & ATIF_PROBE_FAIL) 469 break; 470 } 471 } 472 } 473 474 int aarp_proxy_probe_network(struct atalk_iface *atif, struct atalk_addr *sa) 475 { 476 int hash, retval = -EPROTONOSUPPORT; 477 struct aarp_entry *entry; 478 unsigned int count; 479 480 /* 481 * we don't currently support LocalTalk or PPP for proxy AARP; 482 * if someone wants to try and add it, have fun 483 */ 484 if (atif->dev->type == ARPHRD_LOCALTLK || 485 atif->dev->type == ARPHRD_PPP) 486 goto out; 487 488 /* 489 * create a new AARP entry with the flags set to be published -- 490 * we need this one to hang around even if it's in use 491 */ 492 entry = aarp_alloc(); 493 retval = -ENOMEM; 494 if (!entry) 495 goto out; 496 497 entry->expires_at = -1; 498 entry->status = ATIF_PROBE; 499 entry->target_addr.s_node = sa->s_node; 500 entry->target_addr.s_net = sa->s_net; 501 entry->dev = atif->dev; 502 503 write_lock_bh(&aarp_lock); 504 505 hash = sa->s_node % (AARP_HASH_SIZE - 1); 506 entry->next = proxies[hash]; 507 proxies[hash] = entry; 508 509 for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { 510 aarp_send_probe(atif->dev, sa); 511 512 /* Defer 1/10th */ 513 write_unlock_bh(&aarp_lock); 514 msleep(100); 515 write_lock_bh(&aarp_lock); 516 517 if (entry->status & ATIF_PROBE_FAIL) 518 break; 519 } 520 521 if (entry->status & ATIF_PROBE_FAIL) { 522 entry->expires_at = jiffies - 1; /* free the entry */ 523 retval = -EADDRINUSE; /* return network full */ 524 } else { /* clear the probing flag */ 525 entry->status &= ~ATIF_PROBE; 526 retval = 1; 527 } 528 529 write_unlock_bh(&aarp_lock); 530 out: 531 return retval; 532 } 533 534 /* Send a DDP frame */ 535 int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb, 536 struct atalk_addr *sa, void *hwaddr) 537 { 538 static char ddp_eth_multicast[ETH_ALEN] = 539 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; 540 int hash; 541 struct aarp_entry *a; 542 543 skb->nh.raw = skb->data; 544 545 /* Check for LocalTalk first */ 546 if (dev->type == ARPHRD_LOCALTLK) { 547 struct atalk_addr *at = atalk_find_dev_addr(dev); 548 struct ddpehdr *ddp = (struct ddpehdr *)skb->data; 549 int ft = 2; 550 551 /* 552 * Compressible ? 553 * 554 * IFF: src_net == dest_net == device_net 555 * (zero matches anything) 556 */ 557 558 if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) && 559 (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) { 560 skb_pull(skb, sizeof(*ddp) - 4); 561 562 /* 563 * The upper two remaining bytes are the port 564 * numbers we just happen to need. Now put the 565 * length in the lower two. 566 */ 567 *((__be16 *)skb->data) = htons(skb->len); 568 ft = 1; 569 } 570 /* 571 * Nice and easy. No AARP type protocols occur here so we can 572 * just shovel it out with a 3 byte LLAP header 573 */ 574 575 skb_push(skb, 3); 576 skb->data[0] = sa->s_node; 577 skb->data[1] = at->s_node; 578 skb->data[2] = ft; 579 skb->dev = dev; 580 goto sendit; 581 } 582 583 /* On a PPP link we neither compress nor aarp. */ 584 if (dev->type == ARPHRD_PPP) { 585 skb->protocol = htons(ETH_P_PPPTALK); 586 skb->dev = dev; 587 goto sendit; 588 } 589 590 /* Non ELAP we cannot do. */ 591 if (dev->type != ARPHRD_ETHER) 592 return -1; 593 594 skb->dev = dev; 595 skb->protocol = htons(ETH_P_ATALK); 596 hash = sa->s_node % (AARP_HASH_SIZE - 1); 597 598 /* Do we have a resolved entry? */ 599 if (sa->s_node == ATADDR_BCAST) { 600 /* Send it */ 601 ddp_dl->request(ddp_dl, skb, ddp_eth_multicast); 602 goto sent; 603 } 604 605 write_lock_bh(&aarp_lock); 606 a = __aarp_find_entry(resolved[hash], dev, sa); 607 608 if (a) { /* Return 1 and fill in the address */ 609 a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10); 610 ddp_dl->request(ddp_dl, skb, a->hwaddr); 611 write_unlock_bh(&aarp_lock); 612 goto sent; 613 } 614 615 /* Do we have an unresolved entry: This is the less common path */ 616 a = __aarp_find_entry(unresolved[hash], dev, sa); 617 if (a) { /* Queue onto the unresolved queue */ 618 skb_queue_tail(&a->packet_queue, skb); 619 goto out_unlock; 620 } 621 622 /* Allocate a new entry */ 623 a = aarp_alloc(); 624 if (!a) { 625 /* Whoops slipped... good job it's an unreliable protocol 8) */ 626 write_unlock_bh(&aarp_lock); 627 return -1; 628 } 629 630 /* Set up the queue */ 631 skb_queue_tail(&a->packet_queue, skb); 632 a->expires_at = jiffies + sysctl_aarp_resolve_time; 633 a->dev = dev; 634 a->next = unresolved[hash]; 635 a->target_addr = *sa; 636 a->xmit_count = 0; 637 unresolved[hash] = a; 638 unresolved_count++; 639 640 /* Send an initial request for the address */ 641 __aarp_send_query(a); 642 643 /* 644 * Switch to fast timer if needed (That is if this is the first 645 * unresolved entry to get added) 646 */ 647 648 if (unresolved_count == 1) 649 mod_timer(&aarp_timer, jiffies + sysctl_aarp_tick_time); 650 651 /* Now finally, it is safe to drop the lock. */ 652 out_unlock: 653 write_unlock_bh(&aarp_lock); 654 655 /* Tell the ddp layer we have taken over for this frame. */ 656 return 0; 657 658 sendit: 659 if (skb->sk) 660 skb->priority = skb->sk->sk_priority; 661 dev_queue_xmit(skb); 662 sent: 663 return 1; 664 } 665 666 /* 667 * An entry in the aarp unresolved queue has become resolved. Send 668 * all the frames queued under it. 669 * 670 * Must run under aarp_lock. 671 */ 672 static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a, 673 int hash) 674 { 675 struct sk_buff *skb; 676 677 while (*list) 678 if (*list == a) { 679 unresolved_count--; 680 *list = a->next; 681 682 /* Move into the resolved list */ 683 a->next = resolved[hash]; 684 resolved[hash] = a; 685 686 /* Kick frames off */ 687 while ((skb = skb_dequeue(&a->packet_queue)) != NULL) { 688 a->expires_at = jiffies + 689 sysctl_aarp_expiry_time * 10; 690 ddp_dl->request(ddp_dl, skb, a->hwaddr); 691 } 692 } else 693 list = &((*list)->next); 694 } 695 696 /* 697 * This is called by the SNAP driver whenever we see an AARP SNAP 698 * frame. We currently only support Ethernet. 699 */ 700 static int aarp_rcv(struct sk_buff *skb, struct net_device *dev, 701 struct packet_type *pt, struct net_device *orig_dev) 702 { 703 struct elapaarp *ea = aarp_hdr(skb); 704 int hash, ret = 0; 705 __u16 function; 706 struct aarp_entry *a; 707 struct atalk_addr sa, *ma, da; 708 struct atalk_iface *ifa; 709 710 /* We only do Ethernet SNAP AARP. */ 711 if (dev->type != ARPHRD_ETHER) 712 goto out0; 713 714 /* Frame size ok? */ 715 if (!skb_pull(skb, sizeof(*ea))) 716 goto out0; 717 718 function = ntohs(ea->function); 719 720 /* Sanity check fields. */ 721 if (function < AARP_REQUEST || function > AARP_PROBE || 722 ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN || 723 ea->pa_src_zero || ea->pa_dst_zero) 724 goto out0; 725 726 /* Looks good. */ 727 hash = ea->pa_src_node % (AARP_HASH_SIZE - 1); 728 729 /* Build an address. */ 730 sa.s_node = ea->pa_src_node; 731 sa.s_net = ea->pa_src_net; 732 733 /* Process the packet. Check for replies of me. */ 734 ifa = atalk_find_dev(dev); 735 if (!ifa) 736 goto out1; 737 738 if (ifa->status & ATIF_PROBE && 739 ifa->address.s_node == ea->pa_dst_node && 740 ifa->address.s_net == ea->pa_dst_net) { 741 ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */ 742 goto out1; 743 } 744 745 /* Check for replies of proxy AARP entries */ 746 da.s_node = ea->pa_dst_node; 747 da.s_net = ea->pa_dst_net; 748 749 write_lock_bh(&aarp_lock); 750 a = __aarp_find_entry(proxies[hash], dev, &da); 751 752 if (a && a->status & ATIF_PROBE) { 753 a->status |= ATIF_PROBE_FAIL; 754 /* 755 * we do not respond to probe or request packets for 756 * this address while we are probing this address 757 */ 758 goto unlock; 759 } 760 761 switch (function) { 762 case AARP_REPLY: 763 if (!unresolved_count) /* Speed up */ 764 break; 765 766 /* Find the entry. */ 767 a = __aarp_find_entry(unresolved[hash], dev, &sa); 768 if (!a || dev != a->dev) 769 break; 770 771 /* We can fill one in - this is good. */ 772 memcpy(a->hwaddr, ea->hw_src, ETH_ALEN); 773 __aarp_resolved(&unresolved[hash], a, hash); 774 if (!unresolved_count) 775 mod_timer(&aarp_timer, 776 jiffies + sysctl_aarp_expiry_time); 777 break; 778 779 case AARP_REQUEST: 780 case AARP_PROBE: 781 782 /* 783 * If it is my address set ma to my address and reply. 784 * We can treat probe and request the same. Probe 785 * simply means we shouldn't cache the querying host, 786 * as in a probe they are proposing an address not 787 * using one. 788 * 789 * Support for proxy-AARP added. We check if the 790 * address is one of our proxies before we toss the 791 * packet out. 792 */ 793 794 sa.s_node = ea->pa_dst_node; 795 sa.s_net = ea->pa_dst_net; 796 797 /* See if we have a matching proxy. */ 798 ma = __aarp_proxy_find(dev, &sa); 799 if (!ma) 800 ma = &ifa->address; 801 else { /* We need to make a copy of the entry. */ 802 da.s_node = sa.s_node; 803 da.s_net = da.s_net; 804 ma = &da; 805 } 806 807 if (function == AARP_PROBE) { 808 /* 809 * A probe implies someone trying to get an 810 * address. So as a precaution flush any 811 * entries we have for this address. 812 */ 813 struct aarp_entry *a; 814 815 a = __aarp_find_entry(resolved[sa.s_node % 816 (AARP_HASH_SIZE - 1)], 817 skb->dev, &sa); 818 819 /* 820 * Make it expire next tick - that avoids us 821 * getting into a probe/flush/learn/probe/ 822 * flush/learn cycle during probing of a slow 823 * to respond host addr. 824 */ 825 if (a) { 826 a->expires_at = jiffies - 1; 827 mod_timer(&aarp_timer, jiffies + 828 sysctl_aarp_tick_time); 829 } 830 } 831 832 if (sa.s_node != ma->s_node) 833 break; 834 835 if (sa.s_net && ma->s_net && sa.s_net != ma->s_net) 836 break; 837 838 sa.s_node = ea->pa_src_node; 839 sa.s_net = ea->pa_src_net; 840 841 /* aarp_my_address has found the address to use for us. 842 */ 843 aarp_send_reply(dev, ma, &sa, ea->hw_src); 844 break; 845 } 846 847 unlock: 848 write_unlock_bh(&aarp_lock); 849 out1: 850 ret = 1; 851 out0: 852 kfree_skb(skb); 853 return ret; 854 } 855 856 static struct notifier_block aarp_notifier = { 857 .notifier_call = aarp_device_event, 858 }; 859 860 static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 }; 861 862 void __init aarp_proto_init(void) 863 { 864 aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv); 865 if (!aarp_dl) 866 printk(KERN_CRIT "Unable to register AARP with SNAP.\n"); 867 init_timer(&aarp_timer); 868 aarp_timer.function = aarp_expire_timeout; 869 aarp_timer.data = 0; 870 aarp_timer.expires = jiffies + sysctl_aarp_expiry_time; 871 add_timer(&aarp_timer); 872 register_netdevice_notifier(&aarp_notifier); 873 } 874 875 /* Remove the AARP entries associated with a device. */ 876 void aarp_device_down(struct net_device *dev) 877 { 878 int ct; 879 880 write_lock_bh(&aarp_lock); 881 882 for (ct = 0; ct < AARP_HASH_SIZE; ct++) { 883 __aarp_expire_device(&resolved[ct], dev); 884 __aarp_expire_device(&unresolved[ct], dev); 885 __aarp_expire_device(&proxies[ct], dev); 886 } 887 888 write_unlock_bh(&aarp_lock); 889 } 890 891 #ifdef CONFIG_PROC_FS 892 struct aarp_iter_state { 893 int bucket; 894 struct aarp_entry **table; 895 }; 896 897 /* 898 * Get the aarp entry that is in the chain described 899 * by the iterator. 900 * If pos is set then skip till that index. 901 * pos = 1 is the first entry 902 */ 903 static struct aarp_entry *iter_next(struct aarp_iter_state *iter, loff_t *pos) 904 { 905 int ct = iter->bucket; 906 struct aarp_entry **table = iter->table; 907 loff_t off = 0; 908 struct aarp_entry *entry; 909 910 rescan: 911 while(ct < AARP_HASH_SIZE) { 912 for (entry = table[ct]; entry; entry = entry->next) { 913 if (!pos || ++off == *pos) { 914 iter->table = table; 915 iter->bucket = ct; 916 return entry; 917 } 918 } 919 ++ct; 920 } 921 922 if (table == resolved) { 923 ct = 0; 924 table = unresolved; 925 goto rescan; 926 } 927 if (table == unresolved) { 928 ct = 0; 929 table = proxies; 930 goto rescan; 931 } 932 return NULL; 933 } 934 935 static void *aarp_seq_start(struct seq_file *seq, loff_t *pos) 936 { 937 struct aarp_iter_state *iter = seq->private; 938 939 read_lock_bh(&aarp_lock); 940 iter->table = resolved; 941 iter->bucket = 0; 942 943 return *pos ? iter_next(iter, pos) : SEQ_START_TOKEN; 944 } 945 946 static void *aarp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 947 { 948 struct aarp_entry *entry = v; 949 struct aarp_iter_state *iter = seq->private; 950 951 ++*pos; 952 953 /* first line after header */ 954 if (v == SEQ_START_TOKEN) 955 entry = iter_next(iter, NULL); 956 957 /* next entry in current bucket */ 958 else if (entry->next) 959 entry = entry->next; 960 961 /* next bucket or table */ 962 else { 963 ++iter->bucket; 964 entry = iter_next(iter, NULL); 965 } 966 return entry; 967 } 968 969 static void aarp_seq_stop(struct seq_file *seq, void *v) 970 { 971 read_unlock_bh(&aarp_lock); 972 } 973 974 static const char *dt2str(unsigned long ticks) 975 { 976 static char buf[32]; 977 978 sprintf(buf, "%ld.%02ld", ticks / HZ, ((ticks % HZ) * 100 ) / HZ); 979 980 return buf; 981 } 982 983 static int aarp_seq_show(struct seq_file *seq, void *v) 984 { 985 struct aarp_iter_state *iter = seq->private; 986 struct aarp_entry *entry = v; 987 unsigned long now = jiffies; 988 989 if (v == SEQ_START_TOKEN) 990 seq_puts(seq, 991 "Address Interface Hardware Address" 992 " Expires LastSend Retry Status\n"); 993 else { 994 seq_printf(seq, "%04X:%02X %-12s", 995 ntohs(entry->target_addr.s_net), 996 (unsigned int) entry->target_addr.s_node, 997 entry->dev ? entry->dev->name : "????"); 998 seq_printf(seq, "%02X:%02X:%02X:%02X:%02X:%02X", 999 entry->hwaddr[0] & 0xFF, 1000 entry->hwaddr[1] & 0xFF, 1001 entry->hwaddr[2] & 0xFF, 1002 entry->hwaddr[3] & 0xFF, 1003 entry->hwaddr[4] & 0xFF, 1004 entry->hwaddr[5] & 0xFF); 1005 seq_printf(seq, " %8s", 1006 dt2str((long)entry->expires_at - (long)now)); 1007 if (iter->table == unresolved) 1008 seq_printf(seq, " %8s %6hu", 1009 dt2str(now - entry->last_sent), 1010 entry->xmit_count); 1011 else 1012 seq_puts(seq, " "); 1013 seq_printf(seq, " %s\n", 1014 (iter->table == resolved) ? "resolved" 1015 : (iter->table == unresolved) ? "unresolved" 1016 : (iter->table == proxies) ? "proxies" 1017 : "unknown"); 1018 } 1019 return 0; 1020 } 1021 1022 static struct seq_operations aarp_seq_ops = { 1023 .start = aarp_seq_start, 1024 .next = aarp_seq_next, 1025 .stop = aarp_seq_stop, 1026 .show = aarp_seq_show, 1027 }; 1028 1029 static int aarp_seq_open(struct inode *inode, struct file *file) 1030 { 1031 struct seq_file *seq; 1032 int rc = -ENOMEM; 1033 struct aarp_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL); 1034 1035 if (!s) 1036 goto out; 1037 1038 rc = seq_open(file, &aarp_seq_ops); 1039 if (rc) 1040 goto out_kfree; 1041 1042 seq = file->private_data; 1043 seq->private = s; 1044 memset(s, 0, sizeof(*s)); 1045 out: 1046 return rc; 1047 out_kfree: 1048 kfree(s); 1049 goto out; 1050 } 1051 1052 struct file_operations atalk_seq_arp_fops = { 1053 .owner = THIS_MODULE, 1054 .open = aarp_seq_open, 1055 .read = seq_read, 1056 .llseek = seq_lseek, 1057 .release = seq_release_private, 1058 }; 1059 #endif 1060 1061 /* General module cleanup. Called from cleanup_module() in ddp.c. */ 1062 void aarp_cleanup_module(void) 1063 { 1064 del_timer_sync(&aarp_timer); 1065 unregister_netdevice_notifier(&aarp_notifier); 1066 unregister_snap_client(aarp_dl); 1067 aarp_purge(); 1068 } 1069