1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * AARP: An implementation of the AppleTalk AARP protocol for 4 * Ethernet 'ELAP'. 5 * 6 * Alan Cox <Alan.Cox@linux.org> 7 * 8 * This doesn't fit cleanly with the IP arp. Potentially we can use 9 * the generic neighbour discovery code to clean this up. 10 * 11 * FIXME: 12 * We ought to handle the retransmits with a single list and a 13 * separate fast timer for when it is needed. 14 * Use neighbour discovery code. 15 * Token Ring Support. 16 * 17 * References: 18 * Inside AppleTalk (2nd Ed). 19 * Fixes: 20 * Jaume Grau - flush caches on AARP_PROBE 21 * Rob Newberry - Added proxy AARP and AARP proc fs, 22 * moved probing from DDP module. 23 * Arnaldo C. Melo - don't mangle rx packets 24 */ 25 26#include <linux/if_arp.h> 27#include <linux/slab.h> 28#include <net/sock.h> 29#include <net/datalink.h> 30#include <net/psnap.h> 31#include <linux/atalk.h> 32#include <linux/delay.h> 33#include <linux/init.h> 34#include <linux/proc_fs.h> 35#include <linux/seq_file.h> 36#include <linux/export.h> 37#include <linux/etherdevice.h> 38 39int sysctl_aarp_expiry_time = AARP_EXPIRY_TIME; 40int sysctl_aarp_tick_time = AARP_TICK_TIME; 41int sysctl_aarp_retransmit_limit = AARP_RETRANSMIT_LIMIT; 42int sysctl_aarp_resolve_time = AARP_RESOLVE_TIME; 43 44/* Lists of aarp entries */ 45/** 46 * struct aarp_entry - AARP entry 47 * @last_sent: Last time we xmitted the aarp request 48 * @packet_queue: Queue of frames wait for resolution 49 * @status: Used for proxy AARP 50 * @expires_at: Entry expiry time 51 * @target_addr: DDP Address 52 * @dev: Device to use 53 * @hwaddr: Physical i/f address of target/router 54 * @xmit_count: When this hits 10 we give up 55 * @next: Next entry in chain 56 */ 57struct aarp_entry { 58 /* These first two are only used for unresolved entries */ 59 unsigned long last_sent; 60 struct sk_buff_head packet_queue; 61 int status; 62 unsigned long expires_at; 63 struct atalk_addr target_addr; 64 struct net_device *dev; 65 char hwaddr[ETH_ALEN]; 66 unsigned short xmit_count; 67 struct aarp_entry *next; 68}; 69 70/* Hashed list of resolved, unresolved and proxy entries */ 71static struct aarp_entry *resolved[AARP_HASH_SIZE]; 72static struct aarp_entry *unresolved[AARP_HASH_SIZE]; 73static struct aarp_entry *proxies[AARP_HASH_SIZE]; 74static int unresolved_count; 75 76/* One lock protects it all. */ 77static DEFINE_RWLOCK(aarp_lock); 78 79/* Used to walk the list and purge/kick entries. */ 80static struct timer_list aarp_timer; 81 82/* 83 * Delete an aarp queue 84 * 85 * Must run under aarp_lock. 86 */ 87static void __aarp_expire(struct aarp_entry *a) 88{ 89 skb_queue_purge(&a->packet_queue); 90 kfree(a); 91} 92 93/* 94 * Send an aarp queue entry request 95 * 96 * Must run under aarp_lock. 97 */ 98static void __aarp_send_query(struct aarp_entry *a) 99{ 100 static unsigned char aarp_eth_multicast[ETH_ALEN] = 101 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; 102 struct net_device *dev = a->dev; 103 struct elapaarp *eah; 104 int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; 105 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); 106 struct atalk_addr *sat = atalk_find_dev_addr(dev); 107 108 if (!skb) 109 return; 110 111 if (!sat) { 112 kfree_skb(skb); 113 return; 114 } 115 116 /* Set up the buffer */ 117 skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length); 118 skb_reset_network_header(skb); 119 skb_reset_transport_header(skb); 120 skb_put(skb, sizeof(*eah)); 121 skb->protocol = htons(ETH_P_ATALK); 122 skb->dev = dev; 123 eah = aarp_hdr(skb); 124 125 /* Set up the ARP */ 126 eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); 127 eah->pa_type = htons(ETH_P_ATALK); 128 eah->hw_len = ETH_ALEN; 129 eah->pa_len = AARP_PA_ALEN; 130 eah->function = htons(AARP_REQUEST); 131 132 ether_addr_copy(eah->hw_src, dev->dev_addr); 133 134 eah->pa_src_zero = 0; 135 eah->pa_src_net = sat->s_net; 136 eah->pa_src_node = sat->s_node; 137 138 eth_zero_addr(eah->hw_dst); 139 140 eah->pa_dst_zero = 0; 141 eah->pa_dst_net = a->target_addr.s_net; 142 eah->pa_dst_node = a->target_addr.s_node; 143 144 /* Send it */ 145 aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); 146 /* Update the sending count */ 147 a->xmit_count++; 148 a->last_sent = jiffies; 149} 150 151/* This runs under aarp_lock and in softint context, so only atomic memory 152 * allocations can be used. */ 153static void aarp_send_reply(struct net_device *dev, struct atalk_addr *us, 154 struct atalk_addr *them, unsigned char *sha) 155{ 156 struct elapaarp *eah; 157 int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length; 158 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); 159 160 if (!skb) 161 return; 162 163 /* Set up the buffer */ 164 skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length); 165 skb_reset_network_header(skb); 166 skb_reset_transport_header(skb); 167 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 ether_addr_copy(eah->hw_src, dev->dev_addr); 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 eth_zero_addr(eah->hw_dst); 187 else 188 ether_addr_copy(eah->hw_dst, sha); 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 203static 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_reset_network_header(skb); 217 skb_reset_transport_header(skb); 218 skb_put(skb, sizeof(*eah)); 219 skb->protocol = htons(ETH_P_ATALK); 220 skb->dev = dev; 221 eah = aarp_hdr(skb); 222 223 /* Set up the ARP */ 224 eah->hw_type = htons(AARP_HW_TYPE_ETHERNET); 225 eah->pa_type = htons(ETH_P_ATALK); 226 eah->hw_len = ETH_ALEN; 227 eah->pa_len = AARP_PA_ALEN; 228 eah->function = htons(AARP_PROBE); 229 230 ether_addr_copy(eah->hw_src, dev->dev_addr); 231 232 eah->pa_src_zero = 0; 233 eah->pa_src_net = us->s_net; 234 eah->pa_src_node = us->s_node; 235 236 eth_zero_addr(eah->hw_dst); 237 238 eah->pa_dst_zero = 0; 239 eah->pa_dst_net = us->s_net; 240 eah->pa_dst_node = us->s_node; 241 242 /* Send it */ 243 aarp_dl->request(aarp_dl, skb, aarp_eth_multicast); 244} 245 246/* 247 * Handle an aarp timer expire 248 * 249 * Must run under the aarp_lock. 250 */ 251 252static void __aarp_expire_timer(struct aarp_entry **n) 253{ 254 struct aarp_entry *t; 255 256 while (*n) 257 /* Expired ? */ 258 if (time_after(jiffies, (*n)->expires_at)) { 259 t = *n; 260 *n = (*n)->next; 261 __aarp_expire(t); 262 } else 263 n = &((*n)->next); 264} 265 266/* 267 * Kick all pending requests 5 times a second. 268 * 269 * Must run under the aarp_lock. 270 */ 271static void __aarp_kick(struct aarp_entry **n) 272{ 273 struct aarp_entry *t; 274 275 while (*n) 276 /* Expired: if this will be the 11th tx, we delete instead. */ 277 if ((*n)->xmit_count >= sysctl_aarp_retransmit_limit) { 278 t = *n; 279 *n = (*n)->next; 280 __aarp_expire(t); 281 } else { 282 __aarp_send_query(*n); 283 n = &((*n)->next); 284 } 285} 286 287/* 288 * A device has gone down. Take all entries referring to the device 289 * and remove them. 290 * 291 * Must run under the aarp_lock. 292 */ 293static void __aarp_expire_device(struct aarp_entry **n, struct net_device *dev) 294{ 295 struct aarp_entry *t; 296 297 while (*n) 298 if ((*n)->dev == dev) { 299 t = *n; 300 *n = (*n)->next; 301 __aarp_expire(t); 302 } else 303 n = &((*n)->next); 304} 305 306/* Handle the timer event */ 307static void aarp_expire_timeout(struct timer_list *unused) 308{ 309 int ct; 310 311 write_lock_bh(&aarp_lock); 312 313 for (ct = 0; ct < AARP_HASH_SIZE; ct++) { 314 __aarp_expire_timer(&resolved[ct]); 315 __aarp_kick(&unresolved[ct]); 316 __aarp_expire_timer(&unresolved[ct]); 317 __aarp_expire_timer(&proxies[ct]); 318 } 319 320 write_unlock_bh(&aarp_lock); 321 mod_timer(&aarp_timer, jiffies + 322 (unresolved_count ? sysctl_aarp_tick_time : 323 sysctl_aarp_expiry_time)); 324} 325 326/* Network device notifier chain handler. */ 327static int aarp_device_event(struct notifier_block *this, unsigned long event, 328 void *ptr) 329{ 330 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 331 int ct; 332 333 if (!net_eq(dev_net(dev), &init_net)) 334 return NOTIFY_DONE; 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 */ 351static 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 */ 363static 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 */ 380static 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 */ 395static 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. */ 411void 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. */ 426static 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 */ 439static 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 const struct net_device_ops *ops = iface->dev->netdev_ops; 444 445 sa->sat_addr.s_node = iface->address.s_node; 446 sa->sat_addr.s_net = ntohs(iface->address.s_net); 447 448 /* We pass the Net:Node to the drivers/cards by a Device ioctl. */ 449 if (!(ops->ndo_do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) { 450 ops->ndo_do_ioctl(iface->dev, &atreq, SIOCGIFADDR); 451 if (iface->address.s_net != htons(sa->sat_addr.s_net) || 452 iface->address.s_node != sa->sat_addr.s_node) 453 iface->status |= ATIF_PROBE_FAIL; 454 455 iface->address.s_net = htons(sa->sat_addr.s_net); 456 iface->address.s_node = sa->sat_addr.s_node; 457 } 458} 459 460 461void aarp_probe_network(struct atalk_iface *atif) 462{ 463 if (atif->dev->type == ARPHRD_LOCALTLK || 464 atif->dev->type == ARPHRD_PPP) 465 aarp_send_probe_phase1(atif); 466 else { 467 unsigned int count; 468 469 for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { 470 aarp_send_probe(atif->dev, &atif->address); 471 472 /* Defer 1/10th */ 473 msleep(100); 474 475 if (atif->status & ATIF_PROBE_FAIL) 476 break; 477 } 478 } 479} 480 481int aarp_proxy_probe_network(struct atalk_iface *atif, struct atalk_addr *sa) 482{ 483 int hash, retval = -EPROTONOSUPPORT; 484 struct aarp_entry *entry; 485 unsigned int count; 486 487 /* 488 * we don't currently support LocalTalk or PPP for proxy AARP; 489 * if someone wants to try and add it, have fun 490 */ 491 if (atif->dev->type == ARPHRD_LOCALTLK || 492 atif->dev->type == ARPHRD_PPP) 493 goto out; 494 495 /* 496 * create a new AARP entry with the flags set to be published -- 497 * we need this one to hang around even if it's in use 498 */ 499 entry = aarp_alloc(); 500 retval = -ENOMEM; 501 if (!entry) 502 goto out; 503 504 entry->expires_at = -1; 505 entry->status = ATIF_PROBE; 506 entry->target_addr.s_node = sa->s_node; 507 entry->target_addr.s_net = sa->s_net; 508 entry->dev = atif->dev; 509 510 write_lock_bh(&aarp_lock); 511 512 hash = sa->s_node % (AARP_HASH_SIZE - 1); 513 entry->next = proxies[hash]; 514 proxies[hash] = entry; 515 516 for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) { 517 aarp_send_probe(atif->dev, sa); 518 519 /* Defer 1/10th */ 520 write_unlock_bh(&aarp_lock); 521 msleep(100); 522 write_lock_bh(&aarp_lock); 523 524 if (entry->status & ATIF_PROBE_FAIL) 525 break; 526 } 527 528 if (entry->status & ATIF_PROBE_FAIL) { 529 entry->expires_at = jiffies - 1; /* free the entry */ 530 retval = -EADDRINUSE; /* return network full */ 531 } else { /* clear the probing flag */ 532 entry->status &= ~ATIF_PROBE; 533 retval = 1; 534 } 535 536 write_unlock_bh(&aarp_lock); 537out: 538 return retval; 539} 540 541/* Send a DDP frame */ 542int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb, 543 struct atalk_addr *sa, void *hwaddr) 544{ 545 static char ddp_eth_multicast[ETH_ALEN] = 546 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF }; 547 int hash; 548 struct aarp_entry *a; 549 550 skb_reset_network_header(skb); 551 552 /* Check for LocalTalk first */ 553 if (dev->type == ARPHRD_LOCALTLK) { 554 struct atalk_addr *at = atalk_find_dev_addr(dev); 555 struct ddpehdr *ddp = (struct ddpehdr *)skb->data; 556 int ft = 2; 557 558 /* 559 * Compressible ? 560 * 561 * IFF: src_net == dest_net == device_net 562 * (zero matches anything) 563 */ 564 565 if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) && 566 (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) { 567 skb_pull(skb, sizeof(*ddp) - 4); 568 569 /* 570 * The upper two remaining bytes are the port 571 * numbers we just happen to need. Now put the 572 * length in the lower two. 573 */ 574 *((__be16 *)skb->data) = htons(skb->len); 575 ft = 1; 576 } 577 /* 578 * Nice and easy. No AARP type protocols occur here so we can 579 * just shovel it out with a 3 byte LLAP header 580 */ 581 582 skb_push(skb, 3); 583 skb->data[0] = sa->s_node; 584 skb->data[1] = at->s_node; 585 skb->data[2] = ft; 586 skb->dev = dev; 587 goto sendit; 588 } 589 590 /* On a PPP link we neither compress nor aarp. */ 591 if (dev->type == ARPHRD_PPP) { 592 skb->protocol = htons(ETH_P_PPPTALK); 593 skb->dev = dev; 594 goto sendit; 595 } 596 597 /* Non ELAP we cannot do. */ 598 if (dev->type != ARPHRD_ETHER) 599 goto free_it; 600 601 skb->dev = dev; 602 skb->protocol = htons(ETH_P_ATALK); 603 hash = sa->s_node % (AARP_HASH_SIZE - 1); 604 605 /* Do we have a resolved entry? */ 606 if (sa->s_node == ATADDR_BCAST) { 607 /* Send it */ 608 ddp_dl->request(ddp_dl, skb, ddp_eth_multicast); 609 goto sent; 610 } 611 612 write_lock_bh(&aarp_lock); 613 a = __aarp_find_entry(resolved[hash], dev, sa); 614 615 if (a) { /* Return 1 and fill in the address */ 616 a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10); 617 ddp_dl->request(ddp_dl, skb, a->hwaddr); 618 write_unlock_bh(&aarp_lock); 619 goto sent; 620 } 621 622 /* Do we have an unresolved entry: This is the less common path */ 623 a = __aarp_find_entry(unresolved[hash], dev, sa); 624 if (a) { /* Queue onto the unresolved queue */ 625 skb_queue_tail(&a->packet_queue, skb); 626 goto out_unlock; 627 } 628 629 /* Allocate a new entry */ 630 a = aarp_alloc(); 631 if (!a) { 632 /* Whoops slipped... good job it's an unreliable protocol 8) */ 633 write_unlock_bh(&aarp_lock); 634 goto free_it; 635 } 636 637 /* Set up the queue */ 638 skb_queue_tail(&a->packet_queue, skb); 639 a->expires_at = jiffies + sysctl_aarp_resolve_time; 640 a->dev = dev; 641 a->next = unresolved[hash]; 642 a->target_addr = *sa; 643 a->xmit_count = 0; 644 unresolved[hash] = a; 645 unresolved_count++; 646 647 /* Send an initial request for the address */ 648 __aarp_send_query(a); 649 650 /* 651 * Switch to fast timer if needed (That is if this is the first 652 * unresolved entry to get added) 653 */ 654 655 if (unresolved_count == 1) 656 mod_timer(&aarp_timer, jiffies + sysctl_aarp_tick_time); 657 658 /* Now finally, it is safe to drop the lock. */ 659out_unlock: 660 write_unlock_bh(&aarp_lock); 661 662 /* Tell the ddp layer we have taken over for this frame. */ 663 goto sent; 664 665sendit: 666 if (skb->sk) 667 skb->priority = READ_ONCE(skb->sk->sk_priority); 668 if (dev_queue_xmit(skb)) 669 goto drop; 670sent: 671 return NET_XMIT_SUCCESS; 672free_it: 673 kfree_skb(skb); 674drop: 675 return NET_XMIT_DROP; 676} 677EXPORT_SYMBOL(aarp_send_ddp); 678 679/* 680 * An entry in the aarp unresolved queue has become resolved. Send 681 * all the frames queued under it. 682 * 683 * Must run under aarp_lock. 684 */ 685static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a, 686 int hash) 687{ 688 struct sk_buff *skb; 689 690 while (*list) 691 if (*list == a) { 692 unresolved_count--; 693 *list = a->next; 694 695 /* Move into the resolved list */ 696 a->next = resolved[hash]; 697 resolved[hash] = a; 698 699 /* Kick frames off */ 700 while ((skb = skb_dequeue(&a->packet_queue)) != NULL) { 701 a->expires_at = jiffies + 702 sysctl_aarp_expiry_time * 10; 703 ddp_dl->request(ddp_dl, skb, a->hwaddr); 704 } 705 } else 706 list = &((*list)->next); 707} 708 709/* 710 * This is called by the SNAP driver whenever we see an AARP SNAP 711 * frame. We currently only support Ethernet. 712 */ 713static int aarp_rcv(struct sk_buff *skb, struct net_device *dev, 714 struct packet_type *pt, struct net_device *orig_dev) 715{ 716 struct elapaarp *ea = aarp_hdr(skb); 717 int hash, ret = 0; 718 __u16 function; 719 struct aarp_entry *a; 720 struct atalk_addr sa, *ma, da; 721 struct atalk_iface *ifa; 722 723 if (!net_eq(dev_net(dev), &init_net)) 724 goto out0; 725 726 /* We only do Ethernet SNAP AARP. */ 727 if (dev->type != ARPHRD_ETHER) 728 goto out0; 729 730 /* Frame size ok? */ 731 if (!skb_pull(skb, sizeof(*ea))) 732 goto out0; 733 734 function = ntohs(ea->function); 735 736 /* Sanity check fields. */ 737 if (function < AARP_REQUEST || function > AARP_PROBE || 738 ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN || 739 ea->pa_src_zero || ea->pa_dst_zero) 740 goto out0; 741 742 /* Looks good. */ 743 hash = ea->pa_src_node % (AARP_HASH_SIZE - 1); 744 745 /* Build an address. */ 746 sa.s_node = ea->pa_src_node; 747 sa.s_net = ea->pa_src_net; 748 749 /* Process the packet. Check for replies of me. */ 750 ifa = atalk_find_dev(dev); 751 if (!ifa) 752 goto out1; 753 754 if (ifa->status & ATIF_PROBE && 755 ifa->address.s_node == ea->pa_dst_node && 756 ifa->address.s_net == ea->pa_dst_net) { 757 ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */ 758 goto out1; 759 } 760 761 /* Check for replies of proxy AARP entries */ 762 da.s_node = ea->pa_dst_node; 763 da.s_net = ea->pa_dst_net; 764 765 write_lock_bh(&aarp_lock); 766 a = __aarp_find_entry(proxies[hash], dev, &da); 767 768 if (a && a->status & ATIF_PROBE) { 769 a->status |= ATIF_PROBE_FAIL; 770 /* 771 * we do not respond to probe or request packets of 772 * this address while we are probing this address 773 */ 774 goto unlock; 775 } 776 777 switch (function) { 778 case AARP_REPLY: 779 if (!unresolved_count) /* Speed up */ 780 break; 781 782 /* Find the entry. */ 783 a = __aarp_find_entry(unresolved[hash], dev, &sa); 784 if (!a || dev != a->dev) 785 break; 786 787 /* We can fill one in - this is good. */ 788 ether_addr_copy(a->hwaddr, ea->hw_src); 789 __aarp_resolved(&unresolved[hash], a, hash); 790 if (!unresolved_count) 791 mod_timer(&aarp_timer, 792 jiffies + sysctl_aarp_expiry_time); 793 break; 794 795 case AARP_REQUEST: 796 case AARP_PROBE: 797 798 /* 799 * If it is my address set ma to my address and reply. 800 * We can treat probe and request the same. Probe 801 * simply means we shouldn't cache the querying host, 802 * as in a probe they are proposing an address not 803 * using one. 804 * 805 * Support for proxy-AARP added. We check if the 806 * address is one of our proxies before we toss the 807 * packet out. 808 */ 809 810 sa.s_node = ea->pa_dst_node; 811 sa.s_net = ea->pa_dst_net; 812 813 /* See if we have a matching proxy. */ 814 ma = __aarp_proxy_find(dev, &sa); 815 if (!ma) 816 ma = &ifa->address; 817 else { /* We need to make a copy of the entry. */ 818 da.s_node = sa.s_node; 819 da.s_net = sa.s_net; 820 ma = &da; 821 } 822 823 if (function == AARP_PROBE) { 824 /* 825 * A probe implies someone trying to get an 826 * address. So as a precaution flush any 827 * entries we have for this address. 828 */ 829 a = __aarp_find_entry(resolved[sa.s_node % 830 (AARP_HASH_SIZE - 1)], 831 skb->dev, &sa); 832 833 /* 834 * Make it expire next tick - that avoids us 835 * getting into a probe/flush/learn/probe/ 836 * flush/learn cycle during probing of a slow 837 * to respond host addr. 838 */ 839 if (a) { 840 a->expires_at = jiffies - 1; 841 mod_timer(&aarp_timer, jiffies + 842 sysctl_aarp_tick_time); 843 } 844 } 845 846 if (sa.s_node != ma->s_node) 847 break; 848 849 if (sa.s_net && ma->s_net && sa.s_net != ma->s_net) 850 break; 851 852 sa.s_node = ea->pa_src_node; 853 sa.s_net = ea->pa_src_net; 854 855 /* aarp_my_address has found the address to use for us. 856 */ 857 aarp_send_reply(dev, ma, &sa, ea->hw_src); 858 break; 859 } 860 861unlock: 862 write_unlock_bh(&aarp_lock); 863out1: 864 ret = 1; 865out0: 866 kfree_skb(skb); 867 return ret; 868} 869 870static struct notifier_block aarp_notifier = { 871 .notifier_call = aarp_device_event, 872}; 873 874static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 }; 875 876int __init aarp_proto_init(void) 877{ 878 int rc; 879 880 aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv); 881 if (!aarp_dl) { 882 printk(KERN_CRIT "Unable to register AARP with SNAP.\n"); 883 return -ENOMEM; 884 } 885 timer_setup(&aarp_timer, aarp_expire_timeout, 0); 886 aarp_timer.expires = jiffies + sysctl_aarp_expiry_time; 887 add_timer(&aarp_timer); 888 rc = register_netdevice_notifier(&aarp_notifier); 889 if (rc) { 890 del_timer_sync(&aarp_timer); 891 unregister_snap_client(aarp_dl); 892 } 893 return rc; 894} 895 896/* Remove the AARP entries associated with a device. */ 897void aarp_device_down(struct net_device *dev) 898{ 899 int ct; 900 901 write_lock_bh(&aarp_lock); 902 903 for (ct = 0; ct < AARP_HASH_SIZE; ct++) { 904 __aarp_expire_device(&resolved[ct], dev); 905 __aarp_expire_device(&unresolved[ct], dev); 906 __aarp_expire_device(&proxies[ct], dev); 907 } 908 909 write_unlock_bh(&aarp_lock); 910} 911 912#ifdef CONFIG_PROC_FS 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 */ 919static 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 951static 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 963static 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 986static void aarp_seq_stop(struct seq_file *seq, void *v) 987 __releases(aarp_lock) 988{ 989 read_unlock_bh(&aarp_lock); 990} 991 992static 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 1001static 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 1034const 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#endif 1041 1042/* General module cleanup. Called from cleanup_module() in ddp.c. */ 1043void aarp_cleanup_module(void) 1044{ 1045 del_timer_sync(&aarp_timer); 1046 unregister_netdevice_notifier(&aarp_notifier); 1047 unregister_snap_client(aarp_dl); 1048 aarp_purge(); 1049} 1050