1 /* linux/net/ipv4/arp.c 2 * 3 * Copyright (C) 1994 by Florian La Roche 4 * 5 * This module implements the Address Resolution Protocol ARP (RFC 826), 6 * which is used to convert IP addresses (or in the future maybe other 7 * high-level addresses) into a low-level hardware address (like an Ethernet 8 * address). 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 * 15 * Fixes: 16 * Alan Cox : Removed the Ethernet assumptions in 17 * Florian's code 18 * Alan Cox : Fixed some small errors in the ARP 19 * logic 20 * Alan Cox : Allow >4K in /proc 21 * Alan Cox : Make ARP add its own protocol entry 22 * Ross Martin : Rewrote arp_rcv() and arp_get_info() 23 * Stephen Henson : Add AX25 support to arp_get_info() 24 * Alan Cox : Drop data when a device is downed. 25 * Alan Cox : Use init_timer(). 26 * Alan Cox : Double lock fixes. 27 * Martin Seine : Move the arphdr structure 28 * to if_arp.h for compatibility. 29 * with BSD based programs. 30 * Andrew Tridgell : Added ARP netmask code and 31 * re-arranged proxy handling. 32 * Alan Cox : Changed to use notifiers. 33 * Niibe Yutaka : Reply for this device or proxies only. 34 * Alan Cox : Don't proxy across hardware types! 35 * Jonathan Naylor : Added support for NET/ROM. 36 * Mike Shaver : RFC1122 checks. 37 * Jonathan Naylor : Only lookup the hardware address for 38 * the correct hardware type. 39 * Germano Caronni : Assorted subtle races. 40 * Craig Schlenter : Don't modify permanent entry 41 * during arp_rcv. 42 * Russ Nelson : Tidied up a few bits. 43 * Alexey Kuznetsov: Major changes to caching and behaviour, 44 * eg intelligent arp probing and 45 * generation 46 * of host down events. 47 * Alan Cox : Missing unlock in device events. 48 * Eckes : ARP ioctl control errors. 49 * Alexey Kuznetsov: Arp free fix. 50 * Manuel Rodriguez: Gratuitous ARP. 51 * Jonathan Layes : Added arpd support through kerneld 52 * message queue (960314) 53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support 54 * Mike McLagan : Routing by source 55 * Stuart Cheshire : Metricom and grat arp fixes 56 * *** FOR 2.1 clean this up *** 57 * Lawrence V. Stefani: (08/12/96) Added FDDI support. 58 * Alan Cox : Took the AP1000 nasty FDDI hack and 59 * folded into the mainstream FDDI code. 60 * Ack spit, Linus how did you allow that 61 * one in... 62 * Jes Sorensen : Make FDDI work again in 2.1.x and 63 * clean up the APFDDI & gen. FDDI bits. 64 * Alexey Kuznetsov: new arp state machine; 65 * now it is in net/core/neighbour.c. 66 * Krzysztof Halasa: Added Frame Relay ARP support. 67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file 68 * Shmulik Hen: Split arp_send to arp_create and 69 * arp_xmit so intermediate drivers like 70 * bonding can change the skb before 71 * sending (e.g. insert 8021q tag). 72 * Harald Welte : convert to make use of jenkins hash 73 */ 74 75 #include <linux/module.h> 76 #include <linux/types.h> 77 #include <linux/string.h> 78 #include <linux/kernel.h> 79 #include <linux/capability.h> 80 #include <linux/socket.h> 81 #include <linux/sockios.h> 82 #include <linux/errno.h> 83 #include <linux/in.h> 84 #include <linux/mm.h> 85 #include <linux/inet.h> 86 #include <linux/inetdevice.h> 87 #include <linux/netdevice.h> 88 #include <linux/etherdevice.h> 89 #include <linux/fddidevice.h> 90 #include <linux/if_arp.h> 91 #include <linux/trdevice.h> 92 #include <linux/skbuff.h> 93 #include <linux/proc_fs.h> 94 #include <linux/seq_file.h> 95 #include <linux/stat.h> 96 #include <linux/init.h> 97 #include <linux/net.h> 98 #include <linux/rcupdate.h> 99 #include <linux/jhash.h> 100 #ifdef CONFIG_SYSCTL 101 #include <linux/sysctl.h> 102 #endif 103 104 #include <net/net_namespace.h> 105 #include <net/ip.h> 106 #include <net/icmp.h> 107 #include <net/route.h> 108 #include <net/protocol.h> 109 #include <net/tcp.h> 110 #include <net/sock.h> 111 #include <net/arp.h> 112 #include <net/ax25.h> 113 #include <net/netrom.h> 114 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 115 #include <net/atmclip.h> 116 struct neigh_table *clip_tbl_hook; 117 #endif 118 119 #include <asm/system.h> 120 #include <asm/uaccess.h> 121 122 #include <linux/netfilter_arp.h> 123 124 /* 125 * Interface to generic neighbour cache. 126 */ 127 static u32 arp_hash(const void *pkey, const struct net_device *dev); 128 static int arp_constructor(struct neighbour *neigh); 129 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 130 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 131 static void parp_redo(struct sk_buff *skb); 132 133 static struct neigh_ops arp_generic_ops = { 134 .family = AF_INET, 135 .solicit = arp_solicit, 136 .error_report = arp_error_report, 137 .output = neigh_resolve_output, 138 .connected_output = neigh_connected_output, 139 .hh_output = dev_queue_xmit, 140 .queue_xmit = dev_queue_xmit, 141 }; 142 143 static struct neigh_ops arp_hh_ops = { 144 .family = AF_INET, 145 .solicit = arp_solicit, 146 .error_report = arp_error_report, 147 .output = neigh_resolve_output, 148 .connected_output = neigh_resolve_output, 149 .hh_output = dev_queue_xmit, 150 .queue_xmit = dev_queue_xmit, 151 }; 152 153 static struct neigh_ops arp_direct_ops = { 154 .family = AF_INET, 155 .output = dev_queue_xmit, 156 .connected_output = dev_queue_xmit, 157 .hh_output = dev_queue_xmit, 158 .queue_xmit = dev_queue_xmit, 159 }; 160 161 struct neigh_ops arp_broken_ops = { 162 .family = AF_INET, 163 .solicit = arp_solicit, 164 .error_report = arp_error_report, 165 .output = neigh_compat_output, 166 .connected_output = neigh_compat_output, 167 .hh_output = dev_queue_xmit, 168 .queue_xmit = dev_queue_xmit, 169 }; 170 171 struct neigh_table arp_tbl = { 172 .family = AF_INET, 173 .entry_size = sizeof(struct neighbour) + 4, 174 .key_len = 4, 175 .hash = arp_hash, 176 .constructor = arp_constructor, 177 .proxy_redo = parp_redo, 178 .id = "arp_cache", 179 .parms = { 180 .tbl = &arp_tbl, 181 .base_reachable_time = 30 * HZ, 182 .retrans_time = 1 * HZ, 183 .gc_staletime = 60 * HZ, 184 .reachable_time = 30 * HZ, 185 .delay_probe_time = 5 * HZ, 186 .queue_len = 3, 187 .ucast_probes = 3, 188 .mcast_probes = 3, 189 .anycast_delay = 1 * HZ, 190 .proxy_delay = (8 * HZ) / 10, 191 .proxy_qlen = 64, 192 .locktime = 1 * HZ, 193 }, 194 .gc_interval = 30 * HZ, 195 .gc_thresh1 = 128, 196 .gc_thresh2 = 512, 197 .gc_thresh3 = 1024, 198 }; 199 200 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 201 { 202 switch (dev->type) { 203 case ARPHRD_ETHER: 204 case ARPHRD_FDDI: 205 case ARPHRD_IEEE802: 206 ip_eth_mc_map(addr, haddr); 207 return 0; 208 case ARPHRD_IEEE802_TR: 209 ip_tr_mc_map(addr, haddr); 210 return 0; 211 case ARPHRD_INFINIBAND: 212 ip_ib_mc_map(addr, dev->broadcast, haddr); 213 return 0; 214 default: 215 if (dir) { 216 memcpy(haddr, dev->broadcast, dev->addr_len); 217 return 0; 218 } 219 } 220 return -EINVAL; 221 } 222 223 224 static u32 arp_hash(const void *pkey, const struct net_device *dev) 225 { 226 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd); 227 } 228 229 static int arp_constructor(struct neighbour *neigh) 230 { 231 __be32 addr = *(__be32*)neigh->primary_key; 232 struct net_device *dev = neigh->dev; 233 struct in_device *in_dev; 234 struct neigh_parms *parms; 235 236 rcu_read_lock(); 237 in_dev = __in_dev_get_rcu(dev); 238 if (in_dev == NULL) { 239 rcu_read_unlock(); 240 return -EINVAL; 241 } 242 243 neigh->type = inet_addr_type(dev_net(dev), addr); 244 245 parms = in_dev->arp_parms; 246 __neigh_parms_put(neigh->parms); 247 neigh->parms = neigh_parms_clone(parms); 248 rcu_read_unlock(); 249 250 if (!dev->header_ops) { 251 neigh->nud_state = NUD_NOARP; 252 neigh->ops = &arp_direct_ops; 253 neigh->output = neigh->ops->queue_xmit; 254 } else { 255 /* Good devices (checked by reading texts, but only Ethernet is 256 tested) 257 258 ARPHRD_ETHER: (ethernet, apfddi) 259 ARPHRD_FDDI: (fddi) 260 ARPHRD_IEEE802: (tr) 261 ARPHRD_METRICOM: (strip) 262 ARPHRD_ARCNET: 263 etc. etc. etc. 264 265 ARPHRD_IPDDP will also work, if author repairs it. 266 I did not it, because this driver does not work even 267 in old paradigm. 268 */ 269 270 #if 1 271 /* So... these "amateur" devices are hopeless. 272 The only thing, that I can say now: 273 It is very sad that we need to keep ugly obsolete 274 code to make them happy. 275 276 They should be moved to more reasonable state, now 277 they use rebuild_header INSTEAD OF hard_start_xmit!!! 278 Besides that, they are sort of out of date 279 (a lot of redundant clones/copies, useless in 2.1), 280 I wonder why people believe that they work. 281 */ 282 switch (dev->type) { 283 default: 284 break; 285 case ARPHRD_ROSE: 286 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 287 case ARPHRD_AX25: 288 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 289 case ARPHRD_NETROM: 290 #endif 291 neigh->ops = &arp_broken_ops; 292 neigh->output = neigh->ops->output; 293 return 0; 294 #endif 295 ;} 296 #endif 297 if (neigh->type == RTN_MULTICAST) { 298 neigh->nud_state = NUD_NOARP; 299 arp_mc_map(addr, neigh->ha, dev, 1); 300 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { 301 neigh->nud_state = NUD_NOARP; 302 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 303 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) { 304 neigh->nud_state = NUD_NOARP; 305 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 306 } 307 308 if (dev->header_ops->cache) 309 neigh->ops = &arp_hh_ops; 310 else 311 neigh->ops = &arp_generic_ops; 312 313 if (neigh->nud_state&NUD_VALID) 314 neigh->output = neigh->ops->connected_output; 315 else 316 neigh->output = neigh->ops->output; 317 } 318 return 0; 319 } 320 321 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 322 { 323 dst_link_failure(skb); 324 kfree_skb(skb); 325 } 326 327 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 328 { 329 __be32 saddr = 0; 330 u8 *dst_ha = NULL; 331 struct net_device *dev = neigh->dev; 332 __be32 target = *(__be32*)neigh->primary_key; 333 int probes = atomic_read(&neigh->probes); 334 struct in_device *in_dev = in_dev_get(dev); 335 336 if (!in_dev) 337 return; 338 339 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 340 default: 341 case 0: /* By default announce any local IP */ 342 if (skb && inet_addr_type(dev_net(dev), ip_hdr(skb)->saddr) == RTN_LOCAL) 343 saddr = ip_hdr(skb)->saddr; 344 break; 345 case 1: /* Restrict announcements of saddr in same subnet */ 346 if (!skb) 347 break; 348 saddr = ip_hdr(skb)->saddr; 349 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { 350 /* saddr should be known to target */ 351 if (inet_addr_onlink(in_dev, target, saddr)) 352 break; 353 } 354 saddr = 0; 355 break; 356 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 357 break; 358 } 359 360 if (in_dev) 361 in_dev_put(in_dev); 362 if (!saddr) 363 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 364 365 if ((probes -= neigh->parms->ucast_probes) < 0) { 366 if (!(neigh->nud_state&NUD_VALID)) 367 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n"); 368 dst_ha = neigh->ha; 369 read_lock_bh(&neigh->lock); 370 } else if ((probes -= neigh->parms->app_probes) < 0) { 371 #ifdef CONFIG_ARPD 372 neigh_app_ns(neigh); 373 #endif 374 return; 375 } 376 377 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 378 dst_ha, dev->dev_addr, NULL); 379 if (dst_ha) 380 read_unlock_bh(&neigh->lock); 381 } 382 383 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 384 { 385 int scope; 386 387 switch (IN_DEV_ARP_IGNORE(in_dev)) { 388 case 0: /* Reply, the tip is already validated */ 389 return 0; 390 case 1: /* Reply only if tip is configured on the incoming interface */ 391 sip = 0; 392 scope = RT_SCOPE_HOST; 393 break; 394 case 2: /* 395 * Reply only if tip is configured on the incoming interface 396 * and is in same subnet as sip 397 */ 398 scope = RT_SCOPE_HOST; 399 break; 400 case 3: /* Do not reply for scope host addresses */ 401 sip = 0; 402 scope = RT_SCOPE_LINK; 403 break; 404 case 4: /* Reserved */ 405 case 5: 406 case 6: 407 case 7: 408 return 0; 409 case 8: /* Do not reply */ 410 return 1; 411 default: 412 return 0; 413 } 414 return !inet_confirm_addr(in_dev, sip, tip, scope); 415 } 416 417 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 418 { 419 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip, 420 .saddr = tip } } }; 421 struct rtable *rt; 422 int flag = 0; 423 /*unsigned long now; */ 424 struct net *net = dev_net(dev); 425 426 if (ip_route_output_key(net, &rt, &fl) < 0) 427 return 1; 428 if (rt->u.dst.dev != dev) { 429 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); 430 flag = 1; 431 } 432 ip_rt_put(rt); 433 return flag; 434 } 435 436 /* OBSOLETE FUNCTIONS */ 437 438 /* 439 * Find an arp mapping in the cache. If not found, post a request. 440 * 441 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 442 * even if it exists. It is supposed that skb->dev was mangled 443 * by a virtual device (eql, shaper). Nobody but broken devices 444 * is allowed to use this function, it is scheduled to be removed. --ANK 445 */ 446 447 static int arp_set_predefined(int addr_hint, unsigned char * haddr, __be32 paddr, struct net_device * dev) 448 { 449 switch (addr_hint) { 450 case RTN_LOCAL: 451 printk(KERN_DEBUG "ARP: arp called for own IP address\n"); 452 memcpy(haddr, dev->dev_addr, dev->addr_len); 453 return 1; 454 case RTN_MULTICAST: 455 arp_mc_map(paddr, haddr, dev, 1); 456 return 1; 457 case RTN_BROADCAST: 458 memcpy(haddr, dev->broadcast, dev->addr_len); 459 return 1; 460 } 461 return 0; 462 } 463 464 465 int arp_find(unsigned char *haddr, struct sk_buff *skb) 466 { 467 struct net_device *dev = skb->dev; 468 __be32 paddr; 469 struct neighbour *n; 470 471 if (!skb->dst) { 472 printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); 473 kfree_skb(skb); 474 return 1; 475 } 476 477 paddr = skb->rtable->rt_gateway; 478 479 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, paddr, dev)) 480 return 0; 481 482 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 483 484 if (n) { 485 n->used = jiffies; 486 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { 487 read_lock_bh(&n->lock); 488 memcpy(haddr, n->ha, dev->addr_len); 489 read_unlock_bh(&n->lock); 490 neigh_release(n); 491 return 0; 492 } 493 neigh_release(n); 494 } else 495 kfree_skb(skb); 496 return 1; 497 } 498 499 /* END OF OBSOLETE FUNCTIONS */ 500 501 int arp_bind_neighbour(struct dst_entry *dst) 502 { 503 struct net_device *dev = dst->dev; 504 struct neighbour *n = dst->neighbour; 505 506 if (dev == NULL) 507 return -EINVAL; 508 if (n == NULL) { 509 __be32 nexthop = ((struct rtable*)dst)->rt_gateway; 510 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT)) 511 nexthop = 0; 512 n = __neigh_lookup_errno( 513 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 514 dev->type == ARPHRD_ATM ? clip_tbl_hook : 515 #endif 516 &arp_tbl, &nexthop, dev); 517 if (IS_ERR(n)) 518 return PTR_ERR(n); 519 dst->neighbour = n; 520 } 521 return 0; 522 } 523 524 /* 525 * Check if we can use proxy ARP for this path 526 */ 527 528 static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt) 529 { 530 struct in_device *out_dev; 531 int imi, omi = -1; 532 533 if (!IN_DEV_PROXY_ARP(in_dev)) 534 return 0; 535 536 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0) 537 return 1; 538 if (imi == -1) 539 return 0; 540 541 /* place to check for proxy_arp for routes */ 542 543 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) { 544 omi = IN_DEV_MEDIUM_ID(out_dev); 545 in_dev_put(out_dev); 546 } 547 return (omi != imi && omi != -1); 548 } 549 550 /* 551 * Interface to link layer: send routine and receive handler. 552 */ 553 554 /* 555 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 556 * message. 557 */ 558 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 559 struct net_device *dev, __be32 src_ip, 560 const unsigned char *dest_hw, 561 const unsigned char *src_hw, 562 const unsigned char *target_hw) 563 { 564 struct sk_buff *skb; 565 struct arphdr *arp; 566 unsigned char *arp_ptr; 567 568 /* 569 * Allocate a buffer 570 */ 571 572 skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC); 573 if (skb == NULL) 574 return NULL; 575 576 skb_reserve(skb, LL_RESERVED_SPACE(dev)); 577 skb_reset_network_header(skb); 578 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); 579 skb->dev = dev; 580 skb->protocol = htons(ETH_P_ARP); 581 if (src_hw == NULL) 582 src_hw = dev->dev_addr; 583 if (dest_hw == NULL) 584 dest_hw = dev->broadcast; 585 586 /* 587 * Fill the device header for the ARP frame 588 */ 589 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 590 goto out; 591 592 /* 593 * Fill out the arp protocol part. 594 * 595 * The arp hardware type should match the device type, except for FDDI, 596 * which (according to RFC 1390) should always equal 1 (Ethernet). 597 */ 598 /* 599 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 600 * DIX code for the protocol. Make these device structure fields. 601 */ 602 switch (dev->type) { 603 default: 604 arp->ar_hrd = htons(dev->type); 605 arp->ar_pro = htons(ETH_P_IP); 606 break; 607 608 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 609 case ARPHRD_AX25: 610 arp->ar_hrd = htons(ARPHRD_AX25); 611 arp->ar_pro = htons(AX25_P_IP); 612 break; 613 614 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 615 case ARPHRD_NETROM: 616 arp->ar_hrd = htons(ARPHRD_NETROM); 617 arp->ar_pro = htons(AX25_P_IP); 618 break; 619 #endif 620 #endif 621 622 #ifdef CONFIG_FDDI 623 case ARPHRD_FDDI: 624 arp->ar_hrd = htons(ARPHRD_ETHER); 625 arp->ar_pro = htons(ETH_P_IP); 626 break; 627 #endif 628 #ifdef CONFIG_TR 629 case ARPHRD_IEEE802_TR: 630 arp->ar_hrd = htons(ARPHRD_IEEE802); 631 arp->ar_pro = htons(ETH_P_IP); 632 break; 633 #endif 634 } 635 636 arp->ar_hln = dev->addr_len; 637 arp->ar_pln = 4; 638 arp->ar_op = htons(type); 639 640 arp_ptr=(unsigned char *)(arp+1); 641 642 memcpy(arp_ptr, src_hw, dev->addr_len); 643 arp_ptr+=dev->addr_len; 644 memcpy(arp_ptr, &src_ip,4); 645 arp_ptr+=4; 646 if (target_hw != NULL) 647 memcpy(arp_ptr, target_hw, dev->addr_len); 648 else 649 memset(arp_ptr, 0, dev->addr_len); 650 arp_ptr+=dev->addr_len; 651 memcpy(arp_ptr, &dest_ip, 4); 652 653 return skb; 654 655 out: 656 kfree_skb(skb); 657 return NULL; 658 } 659 660 /* 661 * Send an arp packet. 662 */ 663 void arp_xmit(struct sk_buff *skb) 664 { 665 /* Send it off, maybe filter it using firewalling first. */ 666 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 667 } 668 669 /* 670 * Create and send an arp packet. 671 */ 672 void arp_send(int type, int ptype, __be32 dest_ip, 673 struct net_device *dev, __be32 src_ip, 674 const unsigned char *dest_hw, const unsigned char *src_hw, 675 const unsigned char *target_hw) 676 { 677 struct sk_buff *skb; 678 679 /* 680 * No arp on this interface. 681 */ 682 683 if (dev->flags&IFF_NOARP) 684 return; 685 686 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 687 dest_hw, src_hw, target_hw); 688 if (skb == NULL) { 689 return; 690 } 691 692 arp_xmit(skb); 693 } 694 695 /* 696 * Process an arp request. 697 */ 698 699 static int arp_process(struct sk_buff *skb) 700 { 701 struct net_device *dev = skb->dev; 702 struct in_device *in_dev = in_dev_get(dev); 703 struct arphdr *arp; 704 unsigned char *arp_ptr; 705 struct rtable *rt; 706 unsigned char *sha; 707 __be32 sip, tip; 708 u16 dev_type = dev->type; 709 int addr_type; 710 struct neighbour *n; 711 struct net *net = dev_net(dev); 712 713 /* arp_rcv below verifies the ARP header and verifies the device 714 * is ARP'able. 715 */ 716 717 if (in_dev == NULL) 718 goto out; 719 720 arp = arp_hdr(skb); 721 722 switch (dev_type) { 723 default: 724 if (arp->ar_pro != htons(ETH_P_IP) || 725 htons(dev_type) != arp->ar_hrd) 726 goto out; 727 break; 728 case ARPHRD_ETHER: 729 case ARPHRD_IEEE802_TR: 730 case ARPHRD_FDDI: 731 case ARPHRD_IEEE802: 732 /* 733 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 734 * devices, according to RFC 2625) devices will accept ARP 735 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 736 * This is the case also of FDDI, where the RFC 1390 says that 737 * FDDI devices should accept ARP hardware of (1) Ethernet, 738 * however, to be more robust, we'll accept both 1 (Ethernet) 739 * or 6 (IEEE 802.2) 740 */ 741 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 742 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 743 arp->ar_pro != htons(ETH_P_IP)) 744 goto out; 745 break; 746 case ARPHRD_AX25: 747 if (arp->ar_pro != htons(AX25_P_IP) || 748 arp->ar_hrd != htons(ARPHRD_AX25)) 749 goto out; 750 break; 751 case ARPHRD_NETROM: 752 if (arp->ar_pro != htons(AX25_P_IP) || 753 arp->ar_hrd != htons(ARPHRD_NETROM)) 754 goto out; 755 break; 756 } 757 758 /* Understand only these message types */ 759 760 if (arp->ar_op != htons(ARPOP_REPLY) && 761 arp->ar_op != htons(ARPOP_REQUEST)) 762 goto out; 763 764 /* 765 * Extract fields 766 */ 767 arp_ptr= (unsigned char *)(arp+1); 768 sha = arp_ptr; 769 arp_ptr += dev->addr_len; 770 memcpy(&sip, arp_ptr, 4); 771 arp_ptr += 4; 772 arp_ptr += dev->addr_len; 773 memcpy(&tip, arp_ptr, 4); 774 /* 775 * Check for bad requests for 127.x.x.x and requests for multicast 776 * addresses. If this is one such, delete it. 777 */ 778 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip)) 779 goto out; 780 781 /* 782 * Special case: We must set Frame Relay source Q.922 address 783 */ 784 if (dev_type == ARPHRD_DLCI) 785 sha = dev->broadcast; 786 787 /* 788 * Process entry. The idea here is we want to send a reply if it is a 789 * request for us or if it is a request for someone else that we hold 790 * a proxy for. We want to add an entry to our cache if it is a reply 791 * to us or if it is a request for our address. 792 * (The assumption for this last is that if someone is requesting our 793 * address, they are probably intending to talk to us, so it saves time 794 * if we cache their address. Their address is also probably not in 795 * our cache, since ours is not in their cache.) 796 * 797 * Putting this another way, we only care about replies if they are to 798 * us, in which case we add them to the cache. For requests, we care 799 * about those for us and those for our proxies. We reply to both, 800 * and in the case of requests for us we add the requester to the arp 801 * cache. 802 */ 803 804 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 805 if (sip == 0) { 806 if (arp->ar_op == htons(ARPOP_REQUEST) && 807 inet_addr_type(net, tip) == RTN_LOCAL && 808 !arp_ignore(in_dev, sip, tip)) 809 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, 810 dev->dev_addr, sha); 811 goto out; 812 } 813 814 if (arp->ar_op == htons(ARPOP_REQUEST) && 815 ip_route_input(skb, tip, sip, 0, dev) == 0) { 816 817 rt = skb->rtable; 818 addr_type = rt->rt_type; 819 820 if (addr_type == RTN_LOCAL) { 821 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 822 if (n) { 823 int dont_send = 0; 824 825 if (!dont_send) 826 dont_send |= arp_ignore(in_dev,sip,tip); 827 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 828 dont_send |= arp_filter(sip,tip,dev); 829 if (!dont_send) 830 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 831 832 neigh_release(n); 833 } 834 goto out; 835 } else if (IN_DEV_FORWARD(in_dev)) { 836 if (addr_type == RTN_UNICAST && rt->u.dst.dev != dev && 837 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) { 838 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 839 if (n) 840 neigh_release(n); 841 842 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 843 skb->pkt_type == PACKET_HOST || 844 in_dev->arp_parms->proxy_delay == 0) { 845 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 846 } else { 847 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); 848 in_dev_put(in_dev); 849 return 0; 850 } 851 goto out; 852 } 853 } 854 } 855 856 /* Update our ARP tables */ 857 858 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 859 860 if (IPV4_DEVCONF_ALL(dev_net(dev), ARP_ACCEPT)) { 861 /* Unsolicited ARP is not accepted by default. 862 It is possible, that this option should be enabled for some 863 devices (strip is candidate) 864 */ 865 if (n == NULL && 866 arp->ar_op == htons(ARPOP_REPLY) && 867 inet_addr_type(net, sip) == RTN_UNICAST) 868 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 869 } 870 871 if (n) { 872 int state = NUD_REACHABLE; 873 int override; 874 875 /* If several different ARP replies follows back-to-back, 876 use the FIRST one. It is possible, if several proxy 877 agents are active. Taking the first reply prevents 878 arp trashing and chooses the fastest router. 879 */ 880 override = time_after(jiffies, n->updated + n->parms->locktime); 881 882 /* Broadcast replies and request packets 883 do not assert neighbour reachability. 884 */ 885 if (arp->ar_op != htons(ARPOP_REPLY) || 886 skb->pkt_type != PACKET_HOST) 887 state = NUD_STALE; 888 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0); 889 neigh_release(n); 890 } 891 892 out: 893 if (in_dev) 894 in_dev_put(in_dev); 895 kfree_skb(skb); 896 return 0; 897 } 898 899 static void parp_redo(struct sk_buff *skb) 900 { 901 arp_process(skb); 902 } 903 904 905 /* 906 * Receive an arp request from the device layer. 907 */ 908 909 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 910 struct packet_type *pt, struct net_device *orig_dev) 911 { 912 struct arphdr *arp; 913 914 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 915 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 916 goto freeskb; 917 918 arp = arp_hdr(skb); 919 if (arp->ar_hln != dev->addr_len || 920 dev->flags & IFF_NOARP || 921 skb->pkt_type == PACKET_OTHERHOST || 922 skb->pkt_type == PACKET_LOOPBACK || 923 arp->ar_pln != 4) 924 goto freeskb; 925 926 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 927 goto out_of_mem; 928 929 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 930 931 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 932 933 freeskb: 934 kfree_skb(skb); 935 out_of_mem: 936 return 0; 937 } 938 939 /* 940 * User level interface (ioctl) 941 */ 942 943 /* 944 * Set (create) an ARP cache entry. 945 */ 946 947 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 948 { 949 if (dev == NULL) { 950 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 951 return 0; 952 } 953 if (__in_dev_get_rtnl(dev)) { 954 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 955 return 0; 956 } 957 return -ENXIO; 958 } 959 960 static int arp_req_set_public(struct net *net, struct arpreq *r, 961 struct net_device *dev) 962 { 963 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 964 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 965 966 if (mask && mask != htonl(0xFFFFFFFF)) 967 return -EINVAL; 968 if (!dev && (r->arp_flags & ATF_COM)) { 969 dev = dev_getbyhwaddr(net, r->arp_ha.sa_family, 970 r->arp_ha.sa_data); 971 if (!dev) 972 return -ENODEV; 973 } 974 if (mask) { 975 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL) 976 return -ENOBUFS; 977 return 0; 978 } 979 980 return arp_req_set_proxy(net, dev, 1); 981 } 982 983 static int arp_req_set(struct net *net, struct arpreq *r, 984 struct net_device * dev) 985 { 986 __be32 ip; 987 struct neighbour *neigh; 988 int err; 989 990 if (r->arp_flags & ATF_PUBL) 991 return arp_req_set_public(net, r, dev); 992 993 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 994 if (r->arp_flags & ATF_PERM) 995 r->arp_flags |= ATF_COM; 996 if (dev == NULL) { 997 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 998 .tos = RTO_ONLINK } } }; 999 struct rtable * rt; 1000 if ((err = ip_route_output_key(net, &rt, &fl)) != 0) 1001 return err; 1002 dev = rt->u.dst.dev; 1003 ip_rt_put(rt); 1004 if (!dev) 1005 return -EINVAL; 1006 } 1007 switch (dev->type) { 1008 #ifdef CONFIG_FDDI 1009 case ARPHRD_FDDI: 1010 /* 1011 * According to RFC 1390, FDDI devices should accept ARP 1012 * hardware types of 1 (Ethernet). However, to be more 1013 * robust, we'll accept hardware types of either 1 (Ethernet) 1014 * or 6 (IEEE 802.2). 1015 */ 1016 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1017 r->arp_ha.sa_family != ARPHRD_ETHER && 1018 r->arp_ha.sa_family != ARPHRD_IEEE802) 1019 return -EINVAL; 1020 break; 1021 #endif 1022 default: 1023 if (r->arp_ha.sa_family != dev->type) 1024 return -EINVAL; 1025 break; 1026 } 1027 1028 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1029 err = PTR_ERR(neigh); 1030 if (!IS_ERR(neigh)) { 1031 unsigned state = NUD_STALE; 1032 if (r->arp_flags & ATF_PERM) 1033 state = NUD_PERMANENT; 1034 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ? 1035 r->arp_ha.sa_data : NULL, state, 1036 NEIGH_UPDATE_F_OVERRIDE| 1037 NEIGH_UPDATE_F_ADMIN); 1038 neigh_release(neigh); 1039 } 1040 return err; 1041 } 1042 1043 static unsigned arp_state_to_flags(struct neighbour *neigh) 1044 { 1045 unsigned flags = 0; 1046 if (neigh->nud_state&NUD_PERMANENT) 1047 flags = ATF_PERM|ATF_COM; 1048 else if (neigh->nud_state&NUD_VALID) 1049 flags = ATF_COM; 1050 return flags; 1051 } 1052 1053 /* 1054 * Get an ARP cache entry. 1055 */ 1056 1057 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1058 { 1059 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1060 struct neighbour *neigh; 1061 int err = -ENXIO; 1062 1063 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1064 if (neigh) { 1065 read_lock_bh(&neigh->lock); 1066 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1067 r->arp_flags = arp_state_to_flags(neigh); 1068 read_unlock_bh(&neigh->lock); 1069 r->arp_ha.sa_family = dev->type; 1070 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1071 neigh_release(neigh); 1072 err = 0; 1073 } 1074 return err; 1075 } 1076 1077 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1078 struct net_device *dev) 1079 { 1080 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1081 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1082 1083 if (mask == htonl(0xFFFFFFFF)) 1084 return pneigh_delete(&arp_tbl, net, &ip, dev); 1085 1086 if (mask) 1087 return -EINVAL; 1088 1089 return arp_req_set_proxy(net, dev, 0); 1090 } 1091 1092 static int arp_req_delete(struct net *net, struct arpreq *r, 1093 struct net_device * dev) 1094 { 1095 int err; 1096 __be32 ip; 1097 struct neighbour *neigh; 1098 1099 if (r->arp_flags & ATF_PUBL) 1100 return arp_req_delete_public(net, r, dev); 1101 1102 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1103 if (dev == NULL) { 1104 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1105 .tos = RTO_ONLINK } } }; 1106 struct rtable * rt; 1107 if ((err = ip_route_output_key(net, &rt, &fl)) != 0) 1108 return err; 1109 dev = rt->u.dst.dev; 1110 ip_rt_put(rt); 1111 if (!dev) 1112 return -EINVAL; 1113 } 1114 err = -ENXIO; 1115 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1116 if (neigh) { 1117 if (neigh->nud_state&~NUD_NOARP) 1118 err = neigh_update(neigh, NULL, NUD_FAILED, 1119 NEIGH_UPDATE_F_OVERRIDE| 1120 NEIGH_UPDATE_F_ADMIN); 1121 neigh_release(neigh); 1122 } 1123 return err; 1124 } 1125 1126 /* 1127 * Handle an ARP layer I/O control request. 1128 */ 1129 1130 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1131 { 1132 int err; 1133 struct arpreq r; 1134 struct net_device *dev = NULL; 1135 1136 switch (cmd) { 1137 case SIOCDARP: 1138 case SIOCSARP: 1139 if (!capable(CAP_NET_ADMIN)) 1140 return -EPERM; 1141 case SIOCGARP: 1142 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1143 if (err) 1144 return -EFAULT; 1145 break; 1146 default: 1147 return -EINVAL; 1148 } 1149 1150 if (r.arp_pa.sa_family != AF_INET) 1151 return -EPFNOSUPPORT; 1152 1153 if (!(r.arp_flags & ATF_PUBL) && 1154 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) 1155 return -EINVAL; 1156 if (!(r.arp_flags & ATF_NETMASK)) 1157 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1158 htonl(0xFFFFFFFFUL); 1159 rtnl_lock(); 1160 if (r.arp_dev[0]) { 1161 err = -ENODEV; 1162 if ((dev = __dev_get_by_name(net, r.arp_dev)) == NULL) 1163 goto out; 1164 1165 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1166 if (!r.arp_ha.sa_family) 1167 r.arp_ha.sa_family = dev->type; 1168 err = -EINVAL; 1169 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1170 goto out; 1171 } else if (cmd == SIOCGARP) { 1172 err = -ENODEV; 1173 goto out; 1174 } 1175 1176 switch (cmd) { 1177 case SIOCDARP: 1178 err = arp_req_delete(net, &r, dev); 1179 break; 1180 case SIOCSARP: 1181 err = arp_req_set(net, &r, dev); 1182 break; 1183 case SIOCGARP: 1184 err = arp_req_get(&r, dev); 1185 if (!err && copy_to_user(arg, &r, sizeof(r))) 1186 err = -EFAULT; 1187 break; 1188 } 1189 out: 1190 rtnl_unlock(); 1191 return err; 1192 } 1193 1194 static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1195 { 1196 struct net_device *dev = ptr; 1197 1198 switch (event) { 1199 case NETDEV_CHANGEADDR: 1200 neigh_changeaddr(&arp_tbl, dev); 1201 rt_cache_flush(dev_net(dev), 0); 1202 break; 1203 default: 1204 break; 1205 } 1206 1207 return NOTIFY_DONE; 1208 } 1209 1210 static struct notifier_block arp_netdev_notifier = { 1211 .notifier_call = arp_netdev_event, 1212 }; 1213 1214 /* Note, that it is not on notifier chain. 1215 It is necessary, that this routine was called after route cache will be 1216 flushed. 1217 */ 1218 void arp_ifdown(struct net_device *dev) 1219 { 1220 neigh_ifdown(&arp_tbl, dev); 1221 } 1222 1223 1224 /* 1225 * Called once on startup. 1226 */ 1227 1228 static struct packet_type arp_packet_type = { 1229 .type = __constant_htons(ETH_P_ARP), 1230 .func = arp_rcv, 1231 }; 1232 1233 static int arp_proc_init(void); 1234 1235 void __init arp_init(void) 1236 { 1237 neigh_table_init(&arp_tbl); 1238 1239 dev_add_pack(&arp_packet_type); 1240 arp_proc_init(); 1241 #ifdef CONFIG_SYSCTL 1242 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, 1243 NET_IPV4_NEIGH, "ipv4", NULL, NULL); 1244 #endif 1245 register_netdevice_notifier(&arp_netdev_notifier); 1246 } 1247 1248 #ifdef CONFIG_PROC_FS 1249 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1250 1251 /* ------------------------------------------------------------------------ */ 1252 /* 1253 * ax25 -> ASCII conversion 1254 */ 1255 static char *ax2asc2(ax25_address *a, char *buf) 1256 { 1257 char c, *s; 1258 int n; 1259 1260 for (n = 0, s = buf; n < 6; n++) { 1261 c = (a->ax25_call[n] >> 1) & 0x7F; 1262 1263 if (c != ' ') *s++ = c; 1264 } 1265 1266 *s++ = '-'; 1267 1268 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { 1269 *s++ = '1'; 1270 n -= 10; 1271 } 1272 1273 *s++ = n + '0'; 1274 *s++ = '\0'; 1275 1276 if (*buf == '\0' || *buf == '-') 1277 return "*"; 1278 1279 return buf; 1280 1281 } 1282 #endif /* CONFIG_AX25 */ 1283 1284 #define HBUFFERLEN 30 1285 1286 static void arp_format_neigh_entry(struct seq_file *seq, 1287 struct neighbour *n) 1288 { 1289 char hbuffer[HBUFFERLEN]; 1290 int k, j; 1291 char tbuf[16]; 1292 struct net_device *dev = n->dev; 1293 int hatype = dev->type; 1294 1295 read_lock(&n->lock); 1296 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1297 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1298 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1299 ax2asc2((ax25_address *)n->ha, hbuffer); 1300 else { 1301 #endif 1302 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1303 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1304 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1305 hbuffer[k++] = ':'; 1306 } 1307 hbuffer[--k] = 0; 1308 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1309 } 1310 #endif 1311 sprintf(tbuf, NIPQUAD_FMT, NIPQUAD(*(u32*)n->primary_key)); 1312 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1313 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1314 read_unlock(&n->lock); 1315 } 1316 1317 static void arp_format_pneigh_entry(struct seq_file *seq, 1318 struct pneigh_entry *n) 1319 { 1320 struct net_device *dev = n->dev; 1321 int hatype = dev ? dev->type : 0; 1322 char tbuf[16]; 1323 1324 sprintf(tbuf, NIPQUAD_FMT, NIPQUAD(*(u32*)n->key)); 1325 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1326 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1327 dev ? dev->name : "*"); 1328 } 1329 1330 static int arp_seq_show(struct seq_file *seq, void *v) 1331 { 1332 if (v == SEQ_START_TOKEN) { 1333 seq_puts(seq, "IP address HW type Flags " 1334 "HW address Mask Device\n"); 1335 } else { 1336 struct neigh_seq_state *state = seq->private; 1337 1338 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1339 arp_format_pneigh_entry(seq, v); 1340 else 1341 arp_format_neigh_entry(seq, v); 1342 } 1343 1344 return 0; 1345 } 1346 1347 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1348 { 1349 /* Don't want to confuse "arp -a" w/ magic entries, 1350 * so we tell the generic iterator to skip NUD_NOARP. 1351 */ 1352 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1353 } 1354 1355 /* ------------------------------------------------------------------------ */ 1356 1357 static const struct seq_operations arp_seq_ops = { 1358 .start = arp_seq_start, 1359 .next = neigh_seq_next, 1360 .stop = neigh_seq_stop, 1361 .show = arp_seq_show, 1362 }; 1363 1364 static int arp_seq_open(struct inode *inode, struct file *file) 1365 { 1366 return seq_open_net(inode, file, &arp_seq_ops, 1367 sizeof(struct neigh_seq_state)); 1368 } 1369 1370 static const struct file_operations arp_seq_fops = { 1371 .owner = THIS_MODULE, 1372 .open = arp_seq_open, 1373 .read = seq_read, 1374 .llseek = seq_lseek, 1375 .release = seq_release_net, 1376 }; 1377 1378 1379 static int __net_init arp_net_init(struct net *net) 1380 { 1381 if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops)) 1382 return -ENOMEM; 1383 return 0; 1384 } 1385 1386 static void __net_exit arp_net_exit(struct net *net) 1387 { 1388 proc_net_remove(net, "arp"); 1389 } 1390 1391 static struct pernet_operations arp_net_ops = { 1392 .init = arp_net_init, 1393 .exit = arp_net_exit, 1394 }; 1395 1396 static int __init arp_proc_init(void) 1397 { 1398 return register_pernet_subsys(&arp_net_ops); 1399 } 1400 1401 #else /* CONFIG_PROC_FS */ 1402 1403 static int __init arp_proc_init(void) 1404 { 1405 return 0; 1406 } 1407 1408 #endif /* CONFIG_PROC_FS */ 1409 1410 EXPORT_SYMBOL(arp_broken_ops); 1411 EXPORT_SYMBOL(arp_find); 1412 EXPORT_SYMBOL(arp_create); 1413 EXPORT_SYMBOL(arp_xmit); 1414 EXPORT_SYMBOL(arp_send); 1415 EXPORT_SYMBOL(arp_tbl); 1416 1417 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 1418 EXPORT_SYMBOL(clip_tbl_hook); 1419 #endif 1420