1 /* linux/net/ipv4/arp.c 2 * 3 * Version: $Id: arp.c,v 1.99 2001/08/30 22:55:42 davem Exp $ 4 * 5 * Copyright (C) 1994 by Florian La Roche 6 * 7 * This module implements the Address Resolution Protocol ARP (RFC 826), 8 * which is used to convert IP addresses (or in the future maybe other 9 * high-level addresses) into a low-level hardware address (like an Ethernet 10 * address). 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * Fixes: 18 * Alan Cox : Removed the Ethernet assumptions in 19 * Florian's code 20 * Alan Cox : Fixed some small errors in the ARP 21 * logic 22 * Alan Cox : Allow >4K in /proc 23 * Alan Cox : Make ARP add its own protocol entry 24 * Ross Martin : Rewrote arp_rcv() and arp_get_info() 25 * Stephen Henson : Add AX25 support to arp_get_info() 26 * Alan Cox : Drop data when a device is downed. 27 * Alan Cox : Use init_timer(). 28 * Alan Cox : Double lock fixes. 29 * Martin Seine : Move the arphdr structure 30 * to if_arp.h for compatibility. 31 * with BSD based programs. 32 * Andrew Tridgell : Added ARP netmask code and 33 * re-arranged proxy handling. 34 * Alan Cox : Changed to use notifiers. 35 * Niibe Yutaka : Reply for this device or proxies only. 36 * Alan Cox : Don't proxy across hardware types! 37 * Jonathan Naylor : Added support for NET/ROM. 38 * Mike Shaver : RFC1122 checks. 39 * Jonathan Naylor : Only lookup the hardware address for 40 * the correct hardware type. 41 * Germano Caronni : Assorted subtle races. 42 * Craig Schlenter : Don't modify permanent entry 43 * during arp_rcv. 44 * Russ Nelson : Tidied up a few bits. 45 * Alexey Kuznetsov: Major changes to caching and behaviour, 46 * eg intelligent arp probing and 47 * generation 48 * of host down events. 49 * Alan Cox : Missing unlock in device events. 50 * Eckes : ARP ioctl control errors. 51 * Alexey Kuznetsov: Arp free fix. 52 * Manuel Rodriguez: Gratuitous ARP. 53 * Jonathan Layes : Added arpd support through kerneld 54 * message queue (960314) 55 * Mike Shaver : /proc/sys/net/ipv4/arp_* support 56 * Mike McLagan : Routing by source 57 * Stuart Cheshire : Metricom and grat arp fixes 58 * *** FOR 2.1 clean this up *** 59 * Lawrence V. Stefani: (08/12/96) Added FDDI support. 60 * Alan Cox : Took the AP1000 nasty FDDI hack and 61 * folded into the mainstream FDDI code. 62 * Ack spit, Linus how did you allow that 63 * one in... 64 * Jes Sorensen : Make FDDI work again in 2.1.x and 65 * clean up the APFDDI & gen. FDDI bits. 66 * Alexey Kuznetsov: new arp state machine; 67 * now it is in net/core/neighbour.c. 68 * Krzysztof Halasa: Added Frame Relay ARP support. 69 * Arnaldo C. Melo : convert /proc/net/arp to seq_file 70 * Shmulik Hen: Split arp_send to arp_create and 71 * arp_xmit so intermediate drivers like 72 * bonding can change the skb before 73 * sending (e.g. insert 8021q tag). 74 * Harald Welte : convert to make use of jenkins hash 75 */ 76 77 #include <linux/module.h> 78 #include <linux/types.h> 79 #include <linux/string.h> 80 #include <linux/kernel.h> 81 #include <linux/capability.h> 82 #include <linux/socket.h> 83 #include <linux/sockios.h> 84 #include <linux/errno.h> 85 #include <linux/in.h> 86 #include <linux/mm.h> 87 #include <linux/inet.h> 88 #include <linux/inetdevice.h> 89 #include <linux/netdevice.h> 90 #include <linux/etherdevice.h> 91 #include <linux/fddidevice.h> 92 #include <linux/if_arp.h> 93 #include <linux/trdevice.h> 94 #include <linux/skbuff.h> 95 #include <linux/proc_fs.h> 96 #include <linux/seq_file.h> 97 #include <linux/stat.h> 98 #include <linux/init.h> 99 #include <linux/net.h> 100 #include <linux/rcupdate.h> 101 #include <linux/jhash.h> 102 #ifdef CONFIG_SYSCTL 103 #include <linux/sysctl.h> 104 #endif 105 106 #include <net/net_namespace.h> 107 #include <net/ip.h> 108 #include <net/icmp.h> 109 #include <net/route.h> 110 #include <net/protocol.h> 111 #include <net/tcp.h> 112 #include <net/sock.h> 113 #include <net/arp.h> 114 #include <net/ax25.h> 115 #include <net/netrom.h> 116 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 117 #include <net/atmclip.h> 118 struct neigh_table *clip_tbl_hook; 119 #endif 120 121 #include <asm/system.h> 122 #include <asm/uaccess.h> 123 124 #include <linux/netfilter_arp.h> 125 126 /* 127 * Interface to generic neighbour cache. 128 */ 129 static u32 arp_hash(const void *pkey, const struct net_device *dev); 130 static int arp_constructor(struct neighbour *neigh); 131 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 132 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 133 static void parp_redo(struct sk_buff *skb); 134 135 static struct neigh_ops arp_generic_ops = { 136 .family = AF_INET, 137 .solicit = arp_solicit, 138 .error_report = arp_error_report, 139 .output = neigh_resolve_output, 140 .connected_output = neigh_connected_output, 141 .hh_output = dev_queue_xmit, 142 .queue_xmit = dev_queue_xmit, 143 }; 144 145 static struct neigh_ops arp_hh_ops = { 146 .family = AF_INET, 147 .solicit = arp_solicit, 148 .error_report = arp_error_report, 149 .output = neigh_resolve_output, 150 .connected_output = neigh_resolve_output, 151 .hh_output = dev_queue_xmit, 152 .queue_xmit = dev_queue_xmit, 153 }; 154 155 static struct neigh_ops arp_direct_ops = { 156 .family = AF_INET, 157 .output = dev_queue_xmit, 158 .connected_output = dev_queue_xmit, 159 .hh_output = dev_queue_xmit, 160 .queue_xmit = dev_queue_xmit, 161 }; 162 163 struct neigh_ops arp_broken_ops = { 164 .family = AF_INET, 165 .solicit = arp_solicit, 166 .error_report = arp_error_report, 167 .output = neigh_compat_output, 168 .connected_output = neigh_compat_output, 169 .hh_output = dev_queue_xmit, 170 .queue_xmit = dev_queue_xmit, 171 }; 172 173 struct neigh_table arp_tbl = { 174 .family = AF_INET, 175 .entry_size = sizeof(struct neighbour) + 4, 176 .key_len = 4, 177 .hash = arp_hash, 178 .constructor = arp_constructor, 179 .proxy_redo = parp_redo, 180 .id = "arp_cache", 181 .parms = { 182 .tbl = &arp_tbl, 183 .base_reachable_time = 30 * HZ, 184 .retrans_time = 1 * HZ, 185 .gc_staletime = 60 * HZ, 186 .reachable_time = 30 * HZ, 187 .delay_probe_time = 5 * HZ, 188 .queue_len = 3, 189 .ucast_probes = 3, 190 .mcast_probes = 3, 191 .anycast_delay = 1 * HZ, 192 .proxy_delay = (8 * HZ) / 10, 193 .proxy_qlen = 64, 194 .locktime = 1 * HZ, 195 }, 196 .gc_interval = 30 * HZ, 197 .gc_thresh1 = 128, 198 .gc_thresh2 = 512, 199 .gc_thresh3 = 1024, 200 }; 201 202 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 203 { 204 switch (dev->type) { 205 case ARPHRD_ETHER: 206 case ARPHRD_FDDI: 207 case ARPHRD_IEEE802: 208 ip_eth_mc_map(addr, haddr); 209 return 0; 210 case ARPHRD_IEEE802_TR: 211 ip_tr_mc_map(addr, haddr); 212 return 0; 213 case ARPHRD_INFINIBAND: 214 ip_ib_mc_map(addr, dev->broadcast, haddr); 215 return 0; 216 default: 217 if (dir) { 218 memcpy(haddr, dev->broadcast, dev->addr_len); 219 return 0; 220 } 221 } 222 return -EINVAL; 223 } 224 225 226 static u32 arp_hash(const void *pkey, const struct net_device *dev) 227 { 228 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd); 229 } 230 231 static int arp_constructor(struct neighbour *neigh) 232 { 233 __be32 addr = *(__be32*)neigh->primary_key; 234 struct net_device *dev = neigh->dev; 235 struct in_device *in_dev; 236 struct neigh_parms *parms; 237 238 neigh->type = inet_addr_type(addr); 239 240 rcu_read_lock(); 241 in_dev = __in_dev_get_rcu(dev); 242 if (in_dev == NULL) { 243 rcu_read_unlock(); 244 return -EINVAL; 245 } 246 247 parms = in_dev->arp_parms; 248 __neigh_parms_put(neigh->parms); 249 neigh->parms = neigh_parms_clone(parms); 250 rcu_read_unlock(); 251 252 if (!dev->header_ops) { 253 neigh->nud_state = NUD_NOARP; 254 neigh->ops = &arp_direct_ops; 255 neigh->output = neigh->ops->queue_xmit; 256 } else { 257 /* Good devices (checked by reading texts, but only Ethernet is 258 tested) 259 260 ARPHRD_ETHER: (ethernet, apfddi) 261 ARPHRD_FDDI: (fddi) 262 ARPHRD_IEEE802: (tr) 263 ARPHRD_METRICOM: (strip) 264 ARPHRD_ARCNET: 265 etc. etc. etc. 266 267 ARPHRD_IPDDP will also work, if author repairs it. 268 I did not it, because this driver does not work even 269 in old paradigm. 270 */ 271 272 #if 1 273 /* So... these "amateur" devices are hopeless. 274 The only thing, that I can say now: 275 It is very sad that we need to keep ugly obsolete 276 code to make them happy. 277 278 They should be moved to more reasonable state, now 279 they use rebuild_header INSTEAD OF hard_start_xmit!!! 280 Besides that, they are sort of out of date 281 (a lot of redundant clones/copies, useless in 2.1), 282 I wonder why people believe that they work. 283 */ 284 switch (dev->type) { 285 default: 286 break; 287 case ARPHRD_ROSE: 288 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 289 case ARPHRD_AX25: 290 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 291 case ARPHRD_NETROM: 292 #endif 293 neigh->ops = &arp_broken_ops; 294 neigh->output = neigh->ops->output; 295 return 0; 296 #endif 297 ;} 298 #endif 299 if (neigh->type == RTN_MULTICAST) { 300 neigh->nud_state = NUD_NOARP; 301 arp_mc_map(addr, neigh->ha, dev, 1); 302 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { 303 neigh->nud_state = NUD_NOARP; 304 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 305 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) { 306 neigh->nud_state = NUD_NOARP; 307 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 308 } 309 310 if (dev->header_ops->cache) 311 neigh->ops = &arp_hh_ops; 312 else 313 neigh->ops = &arp_generic_ops; 314 315 if (neigh->nud_state&NUD_VALID) 316 neigh->output = neigh->ops->connected_output; 317 else 318 neigh->output = neigh->ops->output; 319 } 320 return 0; 321 } 322 323 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 324 { 325 dst_link_failure(skb); 326 kfree_skb(skb); 327 } 328 329 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 330 { 331 __be32 saddr = 0; 332 u8 *dst_ha = NULL; 333 struct net_device *dev = neigh->dev; 334 __be32 target = *(__be32*)neigh->primary_key; 335 int probes = atomic_read(&neigh->probes); 336 struct in_device *in_dev = in_dev_get(dev); 337 338 if (!in_dev) 339 return; 340 341 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 342 default: 343 case 0: /* By default announce any local IP */ 344 if (skb && inet_addr_type(ip_hdr(skb)->saddr) == RTN_LOCAL) 345 saddr = ip_hdr(skb)->saddr; 346 break; 347 case 1: /* Restrict announcements of saddr in same subnet */ 348 if (!skb) 349 break; 350 saddr = ip_hdr(skb)->saddr; 351 if (inet_addr_type(saddr) == RTN_LOCAL) { 352 /* saddr should be known to target */ 353 if (inet_addr_onlink(in_dev, target, saddr)) 354 break; 355 } 356 saddr = 0; 357 break; 358 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 359 break; 360 } 361 362 if (in_dev) 363 in_dev_put(in_dev); 364 if (!saddr) 365 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 366 367 if ((probes -= neigh->parms->ucast_probes) < 0) { 368 if (!(neigh->nud_state&NUD_VALID)) 369 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n"); 370 dst_ha = neigh->ha; 371 read_lock_bh(&neigh->lock); 372 } else if ((probes -= neigh->parms->app_probes) < 0) { 373 #ifdef CONFIG_ARPD 374 neigh_app_ns(neigh); 375 #endif 376 return; 377 } 378 379 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 380 dst_ha, dev->dev_addr, NULL); 381 if (dst_ha) 382 read_unlock_bh(&neigh->lock); 383 } 384 385 static int arp_ignore(struct in_device *in_dev, struct net_device *dev, 386 __be32 sip, __be32 tip) 387 { 388 int scope; 389 390 switch (IN_DEV_ARP_IGNORE(in_dev)) { 391 case 0: /* Reply, the tip is already validated */ 392 return 0; 393 case 1: /* Reply only if tip is configured on the incoming interface */ 394 sip = 0; 395 scope = RT_SCOPE_HOST; 396 break; 397 case 2: /* 398 * Reply only if tip is configured on the incoming interface 399 * and is in same subnet as sip 400 */ 401 scope = RT_SCOPE_HOST; 402 break; 403 case 3: /* Do not reply for scope host addresses */ 404 sip = 0; 405 scope = RT_SCOPE_LINK; 406 dev = NULL; 407 break; 408 case 4: /* Reserved */ 409 case 5: 410 case 6: 411 case 7: 412 return 0; 413 case 8: /* Do not reply */ 414 return 1; 415 default: 416 return 0; 417 } 418 return !inet_confirm_addr(dev, sip, tip, scope); 419 } 420 421 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 422 { 423 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip, 424 .saddr = tip } } }; 425 struct rtable *rt; 426 int flag = 0; 427 /*unsigned long now; */ 428 429 if (ip_route_output_key(&rt, &fl) < 0) 430 return 1; 431 if (rt->u.dst.dev != dev) { 432 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER); 433 flag = 1; 434 } 435 ip_rt_put(rt); 436 return flag; 437 } 438 439 /* OBSOLETE FUNCTIONS */ 440 441 /* 442 * Find an arp mapping in the cache. If not found, post a request. 443 * 444 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 445 * even if it exists. It is supposed that skb->dev was mangled 446 * by a virtual device (eql, shaper). Nobody but broken devices 447 * is allowed to use this function, it is scheduled to be removed. --ANK 448 */ 449 450 static int arp_set_predefined(int addr_hint, unsigned char * haddr, __be32 paddr, struct net_device * dev) 451 { 452 switch (addr_hint) { 453 case RTN_LOCAL: 454 printk(KERN_DEBUG "ARP: arp called for own IP address\n"); 455 memcpy(haddr, dev->dev_addr, dev->addr_len); 456 return 1; 457 case RTN_MULTICAST: 458 arp_mc_map(paddr, haddr, dev, 1); 459 return 1; 460 case RTN_BROADCAST: 461 memcpy(haddr, dev->broadcast, dev->addr_len); 462 return 1; 463 } 464 return 0; 465 } 466 467 468 int arp_find(unsigned char *haddr, struct sk_buff *skb) 469 { 470 struct net_device *dev = skb->dev; 471 __be32 paddr; 472 struct neighbour *n; 473 474 if (!skb->dst) { 475 printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); 476 kfree_skb(skb); 477 return 1; 478 } 479 480 paddr = ((struct rtable*)skb->dst)->rt_gateway; 481 482 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev)) 483 return 0; 484 485 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 486 487 if (n) { 488 n->used = jiffies; 489 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { 490 read_lock_bh(&n->lock); 491 memcpy(haddr, n->ha, dev->addr_len); 492 read_unlock_bh(&n->lock); 493 neigh_release(n); 494 return 0; 495 } 496 neigh_release(n); 497 } else 498 kfree_skb(skb); 499 return 1; 500 } 501 502 /* END OF OBSOLETE FUNCTIONS */ 503 504 int arp_bind_neighbour(struct dst_entry *dst) 505 { 506 struct net_device *dev = dst->dev; 507 struct neighbour *n = dst->neighbour; 508 509 if (dev == NULL) 510 return -EINVAL; 511 if (n == NULL) { 512 __be32 nexthop = ((struct rtable*)dst)->rt_gateway; 513 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT)) 514 nexthop = 0; 515 n = __neigh_lookup_errno( 516 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 517 dev->type == ARPHRD_ATM ? clip_tbl_hook : 518 #endif 519 &arp_tbl, &nexthop, dev); 520 if (IS_ERR(n)) 521 return PTR_ERR(n); 522 dst->neighbour = n; 523 } 524 return 0; 525 } 526 527 /* 528 * Check if we can use proxy ARP for this path 529 */ 530 531 static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt) 532 { 533 struct in_device *out_dev; 534 int imi, omi = -1; 535 536 if (!IN_DEV_PROXY_ARP(in_dev)) 537 return 0; 538 539 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0) 540 return 1; 541 if (imi == -1) 542 return 0; 543 544 /* place to check for proxy_arp for routes */ 545 546 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) { 547 omi = IN_DEV_MEDIUM_ID(out_dev); 548 in_dev_put(out_dev); 549 } 550 return (omi != imi && omi != -1); 551 } 552 553 /* 554 * Interface to link layer: send routine and receive handler. 555 */ 556 557 /* 558 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 559 * message. 560 */ 561 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 562 struct net_device *dev, __be32 src_ip, 563 unsigned char *dest_hw, unsigned char *src_hw, 564 unsigned char *target_hw) 565 { 566 struct sk_buff *skb; 567 struct arphdr *arp; 568 unsigned char *arp_ptr; 569 570 /* 571 * Allocate a buffer 572 */ 573 574 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) 575 + LL_RESERVED_SPACE(dev), GFP_ATOMIC); 576 if (skb == NULL) 577 return NULL; 578 579 skb_reserve(skb, LL_RESERVED_SPACE(dev)); 580 skb_reset_network_header(skb); 581 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4)); 582 skb->dev = dev; 583 skb->protocol = htons(ETH_P_ARP); 584 if (src_hw == NULL) 585 src_hw = dev->dev_addr; 586 if (dest_hw == NULL) 587 dest_hw = dev->broadcast; 588 589 /* 590 * Fill the device header for the ARP frame 591 */ 592 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 593 goto out; 594 595 /* 596 * Fill out the arp protocol part. 597 * 598 * The arp hardware type should match the device type, except for FDDI, 599 * which (according to RFC 1390) should always equal 1 (Ethernet). 600 */ 601 /* 602 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 603 * DIX code for the protocol. Make these device structure fields. 604 */ 605 switch (dev->type) { 606 default: 607 arp->ar_hrd = htons(dev->type); 608 arp->ar_pro = htons(ETH_P_IP); 609 break; 610 611 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 612 case ARPHRD_AX25: 613 arp->ar_hrd = htons(ARPHRD_AX25); 614 arp->ar_pro = htons(AX25_P_IP); 615 break; 616 617 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 618 case ARPHRD_NETROM: 619 arp->ar_hrd = htons(ARPHRD_NETROM); 620 arp->ar_pro = htons(AX25_P_IP); 621 break; 622 #endif 623 #endif 624 625 #ifdef CONFIG_FDDI 626 case ARPHRD_FDDI: 627 arp->ar_hrd = htons(ARPHRD_ETHER); 628 arp->ar_pro = htons(ETH_P_IP); 629 break; 630 #endif 631 #ifdef CONFIG_TR 632 case ARPHRD_IEEE802_TR: 633 arp->ar_hrd = htons(ARPHRD_IEEE802); 634 arp->ar_pro = htons(ETH_P_IP); 635 break; 636 #endif 637 } 638 639 arp->ar_hln = dev->addr_len; 640 arp->ar_pln = 4; 641 arp->ar_op = htons(type); 642 643 arp_ptr=(unsigned char *)(arp+1); 644 645 memcpy(arp_ptr, src_hw, dev->addr_len); 646 arp_ptr+=dev->addr_len; 647 memcpy(arp_ptr, &src_ip,4); 648 arp_ptr+=4; 649 if (target_hw != NULL) 650 memcpy(arp_ptr, target_hw, dev->addr_len); 651 else 652 memset(arp_ptr, 0, dev->addr_len); 653 arp_ptr+=dev->addr_len; 654 memcpy(arp_ptr, &dest_ip, 4); 655 656 return skb; 657 658 out: 659 kfree_skb(skb); 660 return NULL; 661 } 662 663 /* 664 * Send an arp packet. 665 */ 666 void arp_xmit(struct sk_buff *skb) 667 { 668 /* Send it off, maybe filter it using firewalling first. */ 669 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 670 } 671 672 /* 673 * Create and send an arp packet. 674 */ 675 void arp_send(int type, int ptype, __be32 dest_ip, 676 struct net_device *dev, __be32 src_ip, 677 unsigned char *dest_hw, unsigned char *src_hw, 678 unsigned char *target_hw) 679 { 680 struct sk_buff *skb; 681 682 /* 683 * No arp on this interface. 684 */ 685 686 if (dev->flags&IFF_NOARP) 687 return; 688 689 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 690 dest_hw, src_hw, target_hw); 691 if (skb == NULL) { 692 return; 693 } 694 695 arp_xmit(skb); 696 } 697 698 /* 699 * Process an arp request. 700 */ 701 702 static int arp_process(struct sk_buff *skb) 703 { 704 struct net_device *dev = skb->dev; 705 struct in_device *in_dev = in_dev_get(dev); 706 struct arphdr *arp; 707 unsigned char *arp_ptr; 708 struct rtable *rt; 709 unsigned char *sha; 710 __be32 sip, tip; 711 u16 dev_type = dev->type; 712 int addr_type; 713 struct neighbour *n; 714 715 /* arp_rcv below verifies the ARP header and verifies the device 716 * is ARP'able. 717 */ 718 719 if (in_dev == NULL) 720 goto out; 721 722 arp = arp_hdr(skb); 723 724 switch (dev_type) { 725 default: 726 if (arp->ar_pro != htons(ETH_P_IP) || 727 htons(dev_type) != arp->ar_hrd) 728 goto out; 729 break; 730 case ARPHRD_ETHER: 731 case ARPHRD_IEEE802_TR: 732 case ARPHRD_FDDI: 733 case ARPHRD_IEEE802: 734 /* 735 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 736 * devices, according to RFC 2625) devices will accept ARP 737 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 738 * This is the case also of FDDI, where the RFC 1390 says that 739 * FDDI devices should accept ARP hardware of (1) Ethernet, 740 * however, to be more robust, we'll accept both 1 (Ethernet) 741 * or 6 (IEEE 802.2) 742 */ 743 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 744 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 745 arp->ar_pro != htons(ETH_P_IP)) 746 goto out; 747 break; 748 case ARPHRD_AX25: 749 if (arp->ar_pro != htons(AX25_P_IP) || 750 arp->ar_hrd != htons(ARPHRD_AX25)) 751 goto out; 752 break; 753 case ARPHRD_NETROM: 754 if (arp->ar_pro != htons(AX25_P_IP) || 755 arp->ar_hrd != htons(ARPHRD_NETROM)) 756 goto out; 757 break; 758 } 759 760 /* Understand only these message types */ 761 762 if (arp->ar_op != htons(ARPOP_REPLY) && 763 arp->ar_op != htons(ARPOP_REQUEST)) 764 goto out; 765 766 /* 767 * Extract fields 768 */ 769 arp_ptr= (unsigned char *)(arp+1); 770 sha = arp_ptr; 771 arp_ptr += dev->addr_len; 772 memcpy(&sip, arp_ptr, 4); 773 arp_ptr += 4; 774 arp_ptr += dev->addr_len; 775 memcpy(&tip, arp_ptr, 4); 776 /* 777 * Check for bad requests for 127.x.x.x and requests for multicast 778 * addresses. If this is one such, delete it. 779 */ 780 if (LOOPBACK(tip) || MULTICAST(tip)) 781 goto out; 782 783 /* 784 * Special case: We must set Frame Relay source Q.922 address 785 */ 786 if (dev_type == ARPHRD_DLCI) 787 sha = dev->broadcast; 788 789 /* 790 * Process entry. The idea here is we want to send a reply if it is a 791 * request for us or if it is a request for someone else that we hold 792 * a proxy for. We want to add an entry to our cache if it is a reply 793 * to us or if it is a request for our address. 794 * (The assumption for this last is that if someone is requesting our 795 * address, they are probably intending to talk to us, so it saves time 796 * if we cache their address. Their address is also probably not in 797 * our cache, since ours is not in their cache.) 798 * 799 * Putting this another way, we only care about replies if they are to 800 * us, in which case we add them to the cache. For requests, we care 801 * about those for us and those for our proxies. We reply to both, 802 * and in the case of requests for us we add the requester to the arp 803 * cache. 804 */ 805 806 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 807 if (sip == 0) { 808 if (arp->ar_op == htons(ARPOP_REQUEST) && 809 inet_addr_type(tip) == RTN_LOCAL && 810 !arp_ignore(in_dev,dev,sip,tip)) 811 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, 812 dev->dev_addr, sha); 813 goto out; 814 } 815 816 if (arp->ar_op == htons(ARPOP_REQUEST) && 817 ip_route_input(skb, tip, sip, 0, dev) == 0) { 818 819 rt = (struct rtable*)skb->dst; 820 addr_type = rt->rt_type; 821 822 if (addr_type == RTN_LOCAL) { 823 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 824 if (n) { 825 int dont_send = 0; 826 827 if (!dont_send) 828 dont_send |= arp_ignore(in_dev,dev,sip,tip); 829 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 830 dont_send |= arp_filter(sip,tip,dev); 831 if (!dont_send) 832 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 833 834 neigh_release(n); 835 } 836 goto out; 837 } else if (IN_DEV_FORWARD(in_dev)) { 838 if ((rt->rt_flags&RTCF_DNAT) || 839 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev && 840 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) { 841 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 842 if (n) 843 neigh_release(n); 844 845 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 846 skb->pkt_type == PACKET_HOST || 847 in_dev->arp_parms->proxy_delay == 0) { 848 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 849 } else { 850 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); 851 in_dev_put(in_dev); 852 return 0; 853 } 854 goto out; 855 } 856 } 857 } 858 859 /* Update our ARP tables */ 860 861 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 862 863 if (IPV4_DEVCONF_ALL(ARP_ACCEPT)) { 864 /* Unsolicited ARP is not accepted by default. 865 It is possible, that this option should be enabled for some 866 devices (strip is candidate) 867 */ 868 if (n == NULL && 869 arp->ar_op == htons(ARPOP_REPLY) && 870 inet_addr_type(sip) == RTN_UNICAST) 871 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 872 } 873 874 if (n) { 875 int state = NUD_REACHABLE; 876 int override; 877 878 /* If several different ARP replies follows back-to-back, 879 use the FIRST one. It is possible, if several proxy 880 agents are active. Taking the first reply prevents 881 arp trashing and chooses the fastest router. 882 */ 883 override = time_after(jiffies, n->updated + n->parms->locktime); 884 885 /* Broadcast replies and request packets 886 do not assert neighbour reachability. 887 */ 888 if (arp->ar_op != htons(ARPOP_REPLY) || 889 skb->pkt_type != PACKET_HOST) 890 state = NUD_STALE; 891 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0); 892 neigh_release(n); 893 } 894 895 out: 896 if (in_dev) 897 in_dev_put(in_dev); 898 kfree_skb(skb); 899 return 0; 900 } 901 902 static void parp_redo(struct sk_buff *skb) 903 { 904 arp_process(skb); 905 } 906 907 908 /* 909 * Receive an arp request from the device layer. 910 */ 911 912 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 913 struct packet_type *pt, struct net_device *orig_dev) 914 { 915 struct arphdr *arp; 916 917 if (dev->nd_net != &init_net) 918 goto freeskb; 919 920 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 921 if (!pskb_may_pull(skb, (sizeof(struct arphdr) + 922 (2 * dev->addr_len) + 923 (2 * sizeof(u32))))) 924 goto freeskb; 925 926 arp = arp_hdr(skb); 927 if (arp->ar_hln != dev->addr_len || 928 dev->flags & IFF_NOARP || 929 skb->pkt_type == PACKET_OTHERHOST || 930 skb->pkt_type == PACKET_LOOPBACK || 931 arp->ar_pln != 4) 932 goto freeskb; 933 934 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 935 goto out_of_mem; 936 937 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 938 939 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 940 941 freeskb: 942 kfree_skb(skb); 943 out_of_mem: 944 return 0; 945 } 946 947 /* 948 * User level interface (ioctl) 949 */ 950 951 /* 952 * Set (create) an ARP cache entry. 953 */ 954 955 static int arp_req_set(struct arpreq *r, struct net_device * dev) 956 { 957 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 958 struct neighbour *neigh; 959 int err; 960 961 if (r->arp_flags&ATF_PUBL) { 962 __be32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; 963 if (mask && mask != htonl(0xFFFFFFFF)) 964 return -EINVAL; 965 if (!dev && (r->arp_flags & ATF_COM)) { 966 dev = dev_getbyhwaddr(&init_net, r->arp_ha.sa_family, r->arp_ha.sa_data); 967 if (!dev) 968 return -ENODEV; 969 } 970 if (mask) { 971 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL) 972 return -ENOBUFS; 973 return 0; 974 } 975 if (dev == NULL) { 976 IPV4_DEVCONF_ALL(PROXY_ARP) = 1; 977 return 0; 978 } 979 if (__in_dev_get_rtnl(dev)) { 980 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, 1); 981 return 0; 982 } 983 return -ENXIO; 984 } 985 986 if (r->arp_flags & ATF_PERM) 987 r->arp_flags |= ATF_COM; 988 if (dev == NULL) { 989 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 990 .tos = RTO_ONLINK } } }; 991 struct rtable * rt; 992 if ((err = ip_route_output_key(&rt, &fl)) != 0) 993 return err; 994 dev = rt->u.dst.dev; 995 ip_rt_put(rt); 996 if (!dev) 997 return -EINVAL; 998 } 999 switch (dev->type) { 1000 #ifdef CONFIG_FDDI 1001 case ARPHRD_FDDI: 1002 /* 1003 * According to RFC 1390, FDDI devices should accept ARP 1004 * hardware types of 1 (Ethernet). However, to be more 1005 * robust, we'll accept hardware types of either 1 (Ethernet) 1006 * or 6 (IEEE 802.2). 1007 */ 1008 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1009 r->arp_ha.sa_family != ARPHRD_ETHER && 1010 r->arp_ha.sa_family != ARPHRD_IEEE802) 1011 return -EINVAL; 1012 break; 1013 #endif 1014 default: 1015 if (r->arp_ha.sa_family != dev->type) 1016 return -EINVAL; 1017 break; 1018 } 1019 1020 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1021 err = PTR_ERR(neigh); 1022 if (!IS_ERR(neigh)) { 1023 unsigned state = NUD_STALE; 1024 if (r->arp_flags & ATF_PERM) 1025 state = NUD_PERMANENT; 1026 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ? 1027 r->arp_ha.sa_data : NULL, state, 1028 NEIGH_UPDATE_F_OVERRIDE| 1029 NEIGH_UPDATE_F_ADMIN); 1030 neigh_release(neigh); 1031 } 1032 return err; 1033 } 1034 1035 static unsigned arp_state_to_flags(struct neighbour *neigh) 1036 { 1037 unsigned flags = 0; 1038 if (neigh->nud_state&NUD_PERMANENT) 1039 flags = ATF_PERM|ATF_COM; 1040 else if (neigh->nud_state&NUD_VALID) 1041 flags = ATF_COM; 1042 return flags; 1043 } 1044 1045 /* 1046 * Get an ARP cache entry. 1047 */ 1048 1049 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1050 { 1051 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1052 struct neighbour *neigh; 1053 int err = -ENXIO; 1054 1055 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1056 if (neigh) { 1057 read_lock_bh(&neigh->lock); 1058 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1059 r->arp_flags = arp_state_to_flags(neigh); 1060 read_unlock_bh(&neigh->lock); 1061 r->arp_ha.sa_family = dev->type; 1062 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1063 neigh_release(neigh); 1064 err = 0; 1065 } 1066 return err; 1067 } 1068 1069 static int arp_req_delete(struct arpreq *r, struct net_device * dev) 1070 { 1071 int err; 1072 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1073 struct neighbour *neigh; 1074 1075 if (r->arp_flags & ATF_PUBL) { 1076 __be32 mask = 1077 ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1078 if (mask == htonl(0xFFFFFFFF)) 1079 return pneigh_delete(&arp_tbl, &ip, dev); 1080 if (mask == 0) { 1081 if (dev == NULL) { 1082 IPV4_DEVCONF_ALL(PROXY_ARP) = 0; 1083 return 0; 1084 } 1085 if (__in_dev_get_rtnl(dev)) { 1086 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), 1087 PROXY_ARP, 0); 1088 return 0; 1089 } 1090 return -ENXIO; 1091 } 1092 return -EINVAL; 1093 } 1094 1095 if (dev == NULL) { 1096 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1097 .tos = RTO_ONLINK } } }; 1098 struct rtable * rt; 1099 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1100 return err; 1101 dev = rt->u.dst.dev; 1102 ip_rt_put(rt); 1103 if (!dev) 1104 return -EINVAL; 1105 } 1106 err = -ENXIO; 1107 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1108 if (neigh) { 1109 if (neigh->nud_state&~NUD_NOARP) 1110 err = neigh_update(neigh, NULL, NUD_FAILED, 1111 NEIGH_UPDATE_F_OVERRIDE| 1112 NEIGH_UPDATE_F_ADMIN); 1113 neigh_release(neigh); 1114 } 1115 return err; 1116 } 1117 1118 /* 1119 * Handle an ARP layer I/O control request. 1120 */ 1121 1122 int arp_ioctl(unsigned int cmd, void __user *arg) 1123 { 1124 int err; 1125 struct arpreq r; 1126 struct net_device *dev = NULL; 1127 1128 switch (cmd) { 1129 case SIOCDARP: 1130 case SIOCSARP: 1131 if (!capable(CAP_NET_ADMIN)) 1132 return -EPERM; 1133 case SIOCGARP: 1134 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1135 if (err) 1136 return -EFAULT; 1137 break; 1138 default: 1139 return -EINVAL; 1140 } 1141 1142 if (r.arp_pa.sa_family != AF_INET) 1143 return -EPFNOSUPPORT; 1144 1145 if (!(r.arp_flags & ATF_PUBL) && 1146 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) 1147 return -EINVAL; 1148 if (!(r.arp_flags & ATF_NETMASK)) 1149 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1150 htonl(0xFFFFFFFFUL); 1151 rtnl_lock(); 1152 if (r.arp_dev[0]) { 1153 err = -ENODEV; 1154 if ((dev = __dev_get_by_name(&init_net, r.arp_dev)) == NULL) 1155 goto out; 1156 1157 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1158 if (!r.arp_ha.sa_family) 1159 r.arp_ha.sa_family = dev->type; 1160 err = -EINVAL; 1161 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1162 goto out; 1163 } else if (cmd == SIOCGARP) { 1164 err = -ENODEV; 1165 goto out; 1166 } 1167 1168 switch (cmd) { 1169 case SIOCDARP: 1170 err = arp_req_delete(&r, dev); 1171 break; 1172 case SIOCSARP: 1173 err = arp_req_set(&r, dev); 1174 break; 1175 case SIOCGARP: 1176 err = arp_req_get(&r, dev); 1177 if (!err && copy_to_user(arg, &r, sizeof(r))) 1178 err = -EFAULT; 1179 break; 1180 } 1181 out: 1182 rtnl_unlock(); 1183 return err; 1184 } 1185 1186 static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1187 { 1188 struct net_device *dev = ptr; 1189 1190 if (dev->nd_net != &init_net) 1191 return NOTIFY_DONE; 1192 1193 switch (event) { 1194 case NETDEV_CHANGEADDR: 1195 neigh_changeaddr(&arp_tbl, dev); 1196 rt_cache_flush(0); 1197 break; 1198 default: 1199 break; 1200 } 1201 1202 return NOTIFY_DONE; 1203 } 1204 1205 static struct notifier_block arp_netdev_notifier = { 1206 .notifier_call = arp_netdev_event, 1207 }; 1208 1209 /* Note, that it is not on notifier chain. 1210 It is necessary, that this routine was called after route cache will be 1211 flushed. 1212 */ 1213 void arp_ifdown(struct net_device *dev) 1214 { 1215 neigh_ifdown(&arp_tbl, dev); 1216 } 1217 1218 1219 /* 1220 * Called once on startup. 1221 */ 1222 1223 static struct packet_type arp_packet_type = { 1224 .type = __constant_htons(ETH_P_ARP), 1225 .func = arp_rcv, 1226 }; 1227 1228 static int arp_proc_init(void); 1229 1230 void __init arp_init(void) 1231 { 1232 neigh_table_init(&arp_tbl); 1233 1234 dev_add_pack(&arp_packet_type); 1235 arp_proc_init(); 1236 #ifdef CONFIG_SYSCTL 1237 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, 1238 NET_IPV4_NEIGH, "ipv4", NULL, NULL); 1239 #endif 1240 register_netdevice_notifier(&arp_netdev_notifier); 1241 } 1242 1243 #ifdef CONFIG_PROC_FS 1244 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1245 1246 /* ------------------------------------------------------------------------ */ 1247 /* 1248 * ax25 -> ASCII conversion 1249 */ 1250 static char *ax2asc2(ax25_address *a, char *buf) 1251 { 1252 char c, *s; 1253 int n; 1254 1255 for (n = 0, s = buf; n < 6; n++) { 1256 c = (a->ax25_call[n] >> 1) & 0x7F; 1257 1258 if (c != ' ') *s++ = c; 1259 } 1260 1261 *s++ = '-'; 1262 1263 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { 1264 *s++ = '1'; 1265 n -= 10; 1266 } 1267 1268 *s++ = n + '0'; 1269 *s++ = '\0'; 1270 1271 if (*buf == '\0' || *buf == '-') 1272 return "*"; 1273 1274 return buf; 1275 1276 } 1277 #endif /* CONFIG_AX25 */ 1278 1279 #define HBUFFERLEN 30 1280 1281 static void arp_format_neigh_entry(struct seq_file *seq, 1282 struct neighbour *n) 1283 { 1284 char hbuffer[HBUFFERLEN]; 1285 const char hexbuf[] = "0123456789ABCDEF"; 1286 int k, j; 1287 char tbuf[16]; 1288 struct net_device *dev = n->dev; 1289 int hatype = dev->type; 1290 1291 read_lock(&n->lock); 1292 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1293 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1294 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1295 ax2asc2((ax25_address *)n->ha, hbuffer); 1296 else { 1297 #endif 1298 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1299 hbuffer[k++] = hexbuf[(n->ha[j] >> 4) & 15]; 1300 hbuffer[k++] = hexbuf[n->ha[j] & 15]; 1301 hbuffer[k++] = ':'; 1302 } 1303 hbuffer[--k] = 0; 1304 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1305 } 1306 #endif 1307 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key)); 1308 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1309 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1310 read_unlock(&n->lock); 1311 } 1312 1313 static void arp_format_pneigh_entry(struct seq_file *seq, 1314 struct pneigh_entry *n) 1315 { 1316 struct net_device *dev = n->dev; 1317 int hatype = dev ? dev->type : 0; 1318 char tbuf[16]; 1319 1320 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key)); 1321 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1322 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1323 dev ? dev->name : "*"); 1324 } 1325 1326 static int arp_seq_show(struct seq_file *seq, void *v) 1327 { 1328 if (v == SEQ_START_TOKEN) { 1329 seq_puts(seq, "IP address HW type Flags " 1330 "HW address Mask Device\n"); 1331 } else { 1332 struct neigh_seq_state *state = seq->private; 1333 1334 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1335 arp_format_pneigh_entry(seq, v); 1336 else 1337 arp_format_neigh_entry(seq, v); 1338 } 1339 1340 return 0; 1341 } 1342 1343 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1344 { 1345 /* Don't want to confuse "arp -a" w/ magic entries, 1346 * so we tell the generic iterator to skip NUD_NOARP. 1347 */ 1348 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1349 } 1350 1351 /* ------------------------------------------------------------------------ */ 1352 1353 static const struct seq_operations arp_seq_ops = { 1354 .start = arp_seq_start, 1355 .next = neigh_seq_next, 1356 .stop = neigh_seq_stop, 1357 .show = arp_seq_show, 1358 }; 1359 1360 static int arp_seq_open(struct inode *inode, struct file *file) 1361 { 1362 return seq_open_private(file, &arp_seq_ops, 1363 sizeof(struct neigh_seq_state)); 1364 } 1365 1366 static const struct file_operations arp_seq_fops = { 1367 .owner = THIS_MODULE, 1368 .open = arp_seq_open, 1369 .read = seq_read, 1370 .llseek = seq_lseek, 1371 .release = seq_release_private, 1372 }; 1373 1374 static int __init arp_proc_init(void) 1375 { 1376 if (!proc_net_fops_create(&init_net, "arp", S_IRUGO, &arp_seq_fops)) 1377 return -ENOMEM; 1378 return 0; 1379 } 1380 1381 #else /* CONFIG_PROC_FS */ 1382 1383 static int __init arp_proc_init(void) 1384 { 1385 return 0; 1386 } 1387 1388 #endif /* CONFIG_PROC_FS */ 1389 1390 EXPORT_SYMBOL(arp_broken_ops); 1391 EXPORT_SYMBOL(arp_find); 1392 EXPORT_SYMBOL(arp_create); 1393 EXPORT_SYMBOL(arp_xmit); 1394 EXPORT_SYMBOL(arp_send); 1395 EXPORT_SYMBOL(arp_tbl); 1396 1397 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 1398 EXPORT_SYMBOL(clip_tbl_hook); 1399 #endif 1400