arp.c revision 444fc8fc3a1f926fa224655b8950bd853368c1a3
1/* linux/net/inet/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/sched.h> 82#include <linux/config.h> 83#include <linux/socket.h> 84#include <linux/sockios.h> 85#include <linux/errno.h> 86#include <linux/in.h> 87#include <linux/mm.h> 88#include <linux/inet.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/ip.h> 107#include <net/icmp.h> 108#include <net/route.h> 109#include <net/protocol.h> 110#include <net/tcp.h> 111#include <net/sock.h> 112#include <net/arp.h> 113#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 114#include <net/ax25.h> 115#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 116#include <net/netrom.h> 117#endif 118#endif 119#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 120#include <net/atmclip.h> 121struct neigh_table *clip_tbl_hook; 122#endif 123 124#include <asm/system.h> 125#include <asm/uaccess.h> 126 127#include <linux/netfilter_arp.h> 128 129/* 130 * Interface to generic neighbour cache. 131 */ 132static u32 arp_hash(const void *pkey, const struct net_device *dev); 133static int arp_constructor(struct neighbour *neigh); 134static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 135static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 136static void parp_redo(struct sk_buff *skb); 137 138static struct neigh_ops arp_generic_ops = { 139 .family = AF_INET, 140 .solicit = arp_solicit, 141 .error_report = arp_error_report, 142 .output = neigh_resolve_output, 143 .connected_output = neigh_connected_output, 144 .hh_output = dev_queue_xmit, 145 .queue_xmit = dev_queue_xmit, 146}; 147 148static struct neigh_ops arp_hh_ops = { 149 .family = AF_INET, 150 .solicit = arp_solicit, 151 .error_report = arp_error_report, 152 .output = neigh_resolve_output, 153 .connected_output = neigh_resolve_output, 154 .hh_output = dev_queue_xmit, 155 .queue_xmit = dev_queue_xmit, 156}; 157 158static struct neigh_ops arp_direct_ops = { 159 .family = AF_INET, 160 .output = dev_queue_xmit, 161 .connected_output = dev_queue_xmit, 162 .hh_output = dev_queue_xmit, 163 .queue_xmit = dev_queue_xmit, 164}; 165 166struct neigh_ops arp_broken_ops = { 167 .family = AF_INET, 168 .solicit = arp_solicit, 169 .error_report = arp_error_report, 170 .output = neigh_compat_output, 171 .connected_output = neigh_compat_output, 172 .hh_output = dev_queue_xmit, 173 .queue_xmit = dev_queue_xmit, 174}; 175 176struct neigh_table arp_tbl = { 177 .family = AF_INET, 178 .entry_size = sizeof(struct neighbour) + 4, 179 .key_len = 4, 180 .hash = arp_hash, 181 .constructor = arp_constructor, 182 .proxy_redo = parp_redo, 183 .id = "arp_cache", 184 .parms = { 185 .tbl = &arp_tbl, 186 .base_reachable_time = 30 * HZ, 187 .retrans_time = 1 * HZ, 188 .gc_staletime = 60 * HZ, 189 .reachable_time = 30 * HZ, 190 .delay_probe_time = 5 * HZ, 191 .queue_len = 3, 192 .ucast_probes = 3, 193 .mcast_probes = 3, 194 .anycast_delay = 1 * HZ, 195 .proxy_delay = (8 * HZ) / 10, 196 .proxy_qlen = 64, 197 .locktime = 1 * HZ, 198 }, 199 .gc_interval = 30 * HZ, 200 .gc_thresh1 = 128, 201 .gc_thresh2 = 512, 202 .gc_thresh3 = 1024, 203}; 204 205int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir) 206{ 207 switch (dev->type) { 208 case ARPHRD_ETHER: 209 case ARPHRD_FDDI: 210 case ARPHRD_IEEE802: 211 ip_eth_mc_map(addr, haddr); 212 return 0; 213 case ARPHRD_IEEE802_TR: 214 ip_tr_mc_map(addr, haddr); 215 return 0; 216 case ARPHRD_INFINIBAND: 217 ip_ib_mc_map(addr, haddr); 218 return 0; 219 default: 220 if (dir) { 221 memcpy(haddr, dev->broadcast, dev->addr_len); 222 return 0; 223 } 224 } 225 return -EINVAL; 226} 227 228 229static u32 arp_hash(const void *pkey, const struct net_device *dev) 230{ 231 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd); 232} 233 234static int arp_constructor(struct neighbour *neigh) 235{ 236 u32 addr = *(u32*)neigh->primary_key; 237 struct net_device *dev = neigh->dev; 238 struct in_device *in_dev; 239 struct neigh_parms *parms; 240 241 neigh->type = inet_addr_type(addr); 242 243 rcu_read_lock(); 244 in_dev = rcu_dereference(__in_dev_get(dev)); 245 if (in_dev == NULL) { 246 rcu_read_unlock(); 247 return -EINVAL; 248 } 249 250 parms = in_dev->arp_parms; 251 __neigh_parms_put(neigh->parms); 252 neigh->parms = neigh_parms_clone(parms); 253 rcu_read_unlock(); 254 255 if (dev->hard_header == NULL) { 256 neigh->nud_state = NUD_NOARP; 257 neigh->ops = &arp_direct_ops; 258 neigh->output = neigh->ops->queue_xmit; 259 } else { 260 /* Good devices (checked by reading texts, but only Ethernet is 261 tested) 262 263 ARPHRD_ETHER: (ethernet, apfddi) 264 ARPHRD_FDDI: (fddi) 265 ARPHRD_IEEE802: (tr) 266 ARPHRD_METRICOM: (strip) 267 ARPHRD_ARCNET: 268 etc. etc. etc. 269 270 ARPHRD_IPDDP will also work, if author repairs it. 271 I did not it, because this driver does not work even 272 in old paradigm. 273 */ 274 275#if 1 276 /* So... these "amateur" devices are hopeless. 277 The only thing, that I can say now: 278 It is very sad that we need to keep ugly obsolete 279 code to make them happy. 280 281 They should be moved to more reasonable state, now 282 they use rebuild_header INSTEAD OF hard_start_xmit!!! 283 Besides that, they are sort of out of date 284 (a lot of redundant clones/copies, useless in 2.1), 285 I wonder why people believe that they work. 286 */ 287 switch (dev->type) { 288 default: 289 break; 290 case ARPHRD_ROSE: 291#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 292 case ARPHRD_AX25: 293#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 294 case ARPHRD_NETROM: 295#endif 296 neigh->ops = &arp_broken_ops; 297 neigh->output = neigh->ops->output; 298 return 0; 299#endif 300 ;} 301#endif 302 if (neigh->type == RTN_MULTICAST) { 303 neigh->nud_state = NUD_NOARP; 304 arp_mc_map(addr, neigh->ha, dev, 1); 305 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { 306 neigh->nud_state = NUD_NOARP; 307 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 308 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) { 309 neigh->nud_state = NUD_NOARP; 310 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 311 } 312 if (dev->hard_header_cache) 313 neigh->ops = &arp_hh_ops; 314 else 315 neigh->ops = &arp_generic_ops; 316 if (neigh->nud_state&NUD_VALID) 317 neigh->output = neigh->ops->connected_output; 318 else 319 neigh->output = neigh->ops->output; 320 } 321 return 0; 322} 323 324static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 325{ 326 dst_link_failure(skb); 327 kfree_skb(skb); 328} 329 330static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 331{ 332 u32 saddr = 0; 333 u8 *dst_ha = NULL; 334 struct net_device *dev = neigh->dev; 335 u32 target = *(u32*)neigh->primary_key; 336 int probes = atomic_read(&neigh->probes); 337 struct in_device *in_dev = in_dev_get(dev); 338 339 if (!in_dev) 340 return; 341 342 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 343 default: 344 case 0: /* By default announce any local IP */ 345 if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL) 346 saddr = skb->nh.iph->saddr; 347 break; 348 case 1: /* Restrict announcements of saddr in same subnet */ 349 if (!skb) 350 break; 351 saddr = skb->nh.iph->saddr; 352 if (inet_addr_type(saddr) == RTN_LOCAL) { 353 /* saddr should be known to target */ 354 if (inet_addr_onlink(in_dev, target, saddr)) 355 break; 356 } 357 saddr = 0; 358 break; 359 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 360 break; 361 } 362 363 if (in_dev) 364 in_dev_put(in_dev); 365 if (!saddr) 366 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 367 368 if ((probes -= neigh->parms->ucast_probes) < 0) { 369 if (!(neigh->nud_state&NUD_VALID)) 370 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n"); 371 dst_ha = neigh->ha; 372 read_lock_bh(&neigh->lock); 373 } else if ((probes -= neigh->parms->app_probes) < 0) { 374#ifdef CONFIG_ARPD 375 neigh_app_ns(neigh); 376#endif 377 return; 378 } 379 380 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 381 dst_ha, dev->dev_addr, NULL); 382 if (dst_ha) 383 read_unlock_bh(&neigh->lock); 384} 385 386static int arp_ignore(struct in_device *in_dev, struct net_device *dev, 387 u32 sip, u32 tip) 388{ 389 int scope; 390 391 switch (IN_DEV_ARP_IGNORE(in_dev)) { 392 case 0: /* Reply, the tip is already validated */ 393 return 0; 394 case 1: /* Reply only if tip is configured on the incoming interface */ 395 sip = 0; 396 scope = RT_SCOPE_HOST; 397 break; 398 case 2: /* 399 * Reply only if tip is configured on the incoming interface 400 * and is in same subnet as sip 401 */ 402 scope = RT_SCOPE_HOST; 403 break; 404 case 3: /* Do not reply for scope host addresses */ 405 sip = 0; 406 scope = RT_SCOPE_LINK; 407 dev = NULL; 408 break; 409 case 4: /* Reserved */ 410 case 5: 411 case 6: 412 case 7: 413 return 0; 414 case 8: /* Do not reply */ 415 return 1; 416 default: 417 return 0; 418 } 419 return !inet_confirm_addr(dev, sip, tip, scope); 420} 421 422static int arp_filter(__u32 sip, __u32 tip, struct net_device *dev) 423{ 424 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip, 425 .saddr = tip } } }; 426 struct rtable *rt; 427 int flag = 0; 428 /*unsigned long now; */ 429 430 if (ip_route_output_key(&rt, &fl) < 0) 431 return 1; 432 if (rt->u.dst.dev != dev) { 433 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER); 434 flag = 1; 435 } 436 ip_rt_put(rt); 437 return flag; 438} 439 440/* OBSOLETE FUNCTIONS */ 441 442/* 443 * Find an arp mapping in the cache. If not found, post a request. 444 * 445 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 446 * even if it exists. It is supposed that skb->dev was mangled 447 * by a virtual device (eql, shaper). Nobody but broken devices 448 * is allowed to use this function, it is scheduled to be removed. --ANK 449 */ 450 451static int arp_set_predefined(int addr_hint, unsigned char * haddr, u32 paddr, struct net_device * dev) 452{ 453 switch (addr_hint) { 454 case RTN_LOCAL: 455 printk(KERN_DEBUG "ARP: arp called for own IP address\n"); 456 memcpy(haddr, dev->dev_addr, dev->addr_len); 457 return 1; 458 case RTN_MULTICAST: 459 arp_mc_map(paddr, haddr, dev, 1); 460 return 1; 461 case RTN_BROADCAST: 462 memcpy(haddr, dev->broadcast, dev->addr_len); 463 return 1; 464 } 465 return 0; 466} 467 468 469int arp_find(unsigned char *haddr, struct sk_buff *skb) 470{ 471 struct net_device *dev = skb->dev; 472 u32 paddr; 473 struct neighbour *n; 474 475 if (!skb->dst) { 476 printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); 477 kfree_skb(skb); 478 return 1; 479 } 480 481 paddr = ((struct rtable*)skb->dst)->rt_gateway; 482 483 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev)) 484 return 0; 485 486 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 487 488 if (n) { 489 n->used = jiffies; 490 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { 491 read_lock_bh(&n->lock); 492 memcpy(haddr, n->ha, dev->addr_len); 493 read_unlock_bh(&n->lock); 494 neigh_release(n); 495 return 0; 496 } 497 neigh_release(n); 498 } else 499 kfree_skb(skb); 500 return 1; 501} 502 503/* END OF OBSOLETE FUNCTIONS */ 504 505int arp_bind_neighbour(struct dst_entry *dst) 506{ 507 struct net_device *dev = dst->dev; 508 struct neighbour *n = dst->neighbour; 509 510 if (dev == NULL) 511 return -EINVAL; 512 if (n == NULL) { 513 u32 nexthop = ((struct rtable*)dst)->rt_gateway; 514 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT)) 515 nexthop = 0; 516 n = __neigh_lookup_errno( 517#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 518 dev->type == ARPHRD_ATM ? clip_tbl_hook : 519#endif 520 &arp_tbl, &nexthop, dev); 521 if (IS_ERR(n)) 522 return PTR_ERR(n); 523 dst->neighbour = n; 524 } 525 return 0; 526} 527 528/* 529 * Check if we can use proxy ARP for this path 530 */ 531 532static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt) 533{ 534 struct in_device *out_dev; 535 int imi, omi = -1; 536 537 if (!IN_DEV_PROXY_ARP(in_dev)) 538 return 0; 539 540 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0) 541 return 1; 542 if (imi == -1) 543 return 0; 544 545 /* place to check for proxy_arp for routes */ 546 547 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) { 548 omi = IN_DEV_MEDIUM_ID(out_dev); 549 in_dev_put(out_dev); 550 } 551 return (omi != imi && omi != -1); 552} 553 554/* 555 * Interface to link layer: send routine and receive handler. 556 */ 557 558/* 559 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 560 * message. 561 */ 562struct sk_buff *arp_create(int type, int ptype, u32 dest_ip, 563 struct net_device *dev, u32 src_ip, 564 unsigned char *dest_hw, unsigned char *src_hw, 565 unsigned char *target_hw) 566{ 567 struct sk_buff *skb; 568 struct arphdr *arp; 569 unsigned char *arp_ptr; 570 571 /* 572 * Allocate a buffer 573 */ 574 575 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) 576 + LL_RESERVED_SPACE(dev), GFP_ATOMIC); 577 if (skb == NULL) 578 return NULL; 579 580 skb_reserve(skb, LL_RESERVED_SPACE(dev)); 581 skb->nh.raw = skb->data; 582 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4)); 583 skb->dev = dev; 584 skb->protocol = htons(ETH_P_ARP); 585 if (src_hw == NULL) 586 src_hw = dev->dev_addr; 587 if (dest_hw == NULL) 588 dest_hw = dev->broadcast; 589 590 /* 591 * Fill the device header for the ARP frame 592 */ 593 if (dev->hard_header && 594 dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0) 595 goto out; 596 597 /* 598 * Fill out the arp protocol part. 599 * 600 * The arp hardware type should match the device type, except for FDDI, 601 * which (according to RFC 1390) should always equal 1 (Ethernet). 602 */ 603 /* 604 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 605 * DIX code for the protocol. Make these device structure fields. 606 */ 607 switch (dev->type) { 608 default: 609 arp->ar_hrd = htons(dev->type); 610 arp->ar_pro = htons(ETH_P_IP); 611 break; 612 613#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 614 case ARPHRD_AX25: 615 arp->ar_hrd = htons(ARPHRD_AX25); 616 arp->ar_pro = htons(AX25_P_IP); 617 break; 618 619#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 620 case ARPHRD_NETROM: 621 arp->ar_hrd = htons(ARPHRD_NETROM); 622 arp->ar_pro = htons(AX25_P_IP); 623 break; 624#endif 625#endif 626 627#ifdef CONFIG_FDDI 628 case ARPHRD_FDDI: 629 arp->ar_hrd = htons(ARPHRD_ETHER); 630 arp->ar_pro = htons(ETH_P_IP); 631 break; 632#endif 633#ifdef CONFIG_TR 634 case ARPHRD_IEEE802_TR: 635 arp->ar_hrd = htons(ARPHRD_IEEE802); 636 arp->ar_pro = htons(ETH_P_IP); 637 break; 638#endif 639 } 640 641 arp->ar_hln = dev->addr_len; 642 arp->ar_pln = 4; 643 arp->ar_op = htons(type); 644 645 arp_ptr=(unsigned char *)(arp+1); 646 647 memcpy(arp_ptr, src_hw, dev->addr_len); 648 arp_ptr+=dev->addr_len; 649 memcpy(arp_ptr, &src_ip,4); 650 arp_ptr+=4; 651 if (target_hw != NULL) 652 memcpy(arp_ptr, target_hw, dev->addr_len); 653 else 654 memset(arp_ptr, 0, dev->addr_len); 655 arp_ptr+=dev->addr_len; 656 memcpy(arp_ptr, &dest_ip, 4); 657 658 return skb; 659 660out: 661 kfree_skb(skb); 662 return NULL; 663} 664 665/* 666 * Send an arp packet. 667 */ 668void arp_xmit(struct sk_buff *skb) 669{ 670 /* Send it off, maybe filter it using firewalling first. */ 671 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 672} 673 674/* 675 * Create and send an arp packet. 676 */ 677void arp_send(int type, int ptype, u32 dest_ip, 678 struct net_device *dev, u32 src_ip, 679 unsigned char *dest_hw, unsigned char *src_hw, 680 unsigned char *target_hw) 681{ 682 struct sk_buff *skb; 683 684 /* 685 * No arp on this interface. 686 */ 687 688 if (dev->flags&IFF_NOARP) 689 return; 690 691 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 692 dest_hw, src_hw, target_hw); 693 if (skb == NULL) { 694 return; 695 } 696 697 arp_xmit(skb); 698} 699 700/* 701 * Process an arp request. 702 */ 703 704static int arp_process(struct sk_buff *skb) 705{ 706 struct net_device *dev = skb->dev; 707 struct in_device *in_dev = in_dev_get(dev); 708 struct arphdr *arp; 709 unsigned char *arp_ptr; 710 struct rtable *rt; 711 unsigned char *sha, *tha; 712 u32 sip, tip; 713 u16 dev_type = dev->type; 714 int addr_type; 715 struct neighbour *n; 716 717 /* arp_rcv below verifies the ARP header and verifies the device 718 * is ARP'able. 719 */ 720 721 if (in_dev == NULL) 722 goto out; 723 724 arp = skb->nh.arph; 725 726 switch (dev_type) { 727 default: 728 if (arp->ar_pro != htons(ETH_P_IP) || 729 htons(dev_type) != arp->ar_hrd) 730 goto out; 731 break; 732#ifdef CONFIG_NET_ETHERNET 733 case ARPHRD_ETHER: 734#endif 735#ifdef CONFIG_TR 736 case ARPHRD_IEEE802_TR: 737#endif 738#ifdef CONFIG_FDDI 739 case ARPHRD_FDDI: 740#endif 741#ifdef CONFIG_NET_FC 742 case ARPHRD_IEEE802: 743#endif 744#if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_TR) || \ 745 defined(CONFIG_FDDI) || defined(CONFIG_NET_FC) 746 /* 747 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 748 * devices, according to RFC 2625) devices will accept ARP 749 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 750 * This is the case also of FDDI, where the RFC 1390 says that 751 * FDDI devices should accept ARP hardware of (1) Ethernet, 752 * however, to be more robust, we'll accept both 1 (Ethernet) 753 * or 6 (IEEE 802.2) 754 */ 755 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 756 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 757 arp->ar_pro != htons(ETH_P_IP)) 758 goto out; 759 break; 760#endif 761#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 762 case ARPHRD_AX25: 763 if (arp->ar_pro != htons(AX25_P_IP) || 764 arp->ar_hrd != htons(ARPHRD_AX25)) 765 goto out; 766 break; 767#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 768 case ARPHRD_NETROM: 769 if (arp->ar_pro != htons(AX25_P_IP) || 770 arp->ar_hrd != htons(ARPHRD_NETROM)) 771 goto out; 772 break; 773#endif 774#endif 775 } 776 777 /* Understand only these message types */ 778 779 if (arp->ar_op != htons(ARPOP_REPLY) && 780 arp->ar_op != htons(ARPOP_REQUEST)) 781 goto out; 782 783/* 784 * Extract fields 785 */ 786 arp_ptr= (unsigned char *)(arp+1); 787 sha = arp_ptr; 788 arp_ptr += dev->addr_len; 789 memcpy(&sip, arp_ptr, 4); 790 arp_ptr += 4; 791 tha = arp_ptr; 792 arp_ptr += dev->addr_len; 793 memcpy(&tip, arp_ptr, 4); 794/* 795 * Check for bad requests for 127.x.x.x and requests for multicast 796 * addresses. If this is one such, delete it. 797 */ 798 if (LOOPBACK(tip) || MULTICAST(tip)) 799 goto out; 800 801/* 802 * Special case: We must set Frame Relay source Q.922 address 803 */ 804 if (dev_type == ARPHRD_DLCI) 805 sha = dev->broadcast; 806 807/* 808 * Process entry. The idea here is we want to send a reply if it is a 809 * request for us or if it is a request for someone else that we hold 810 * a proxy for. We want to add an entry to our cache if it is a reply 811 * to us or if it is a request for our address. 812 * (The assumption for this last is that if someone is requesting our 813 * address, they are probably intending to talk to us, so it saves time 814 * if we cache their address. Their address is also probably not in 815 * our cache, since ours is not in their cache.) 816 * 817 * Putting this another way, we only care about replies if they are to 818 * us, in which case we add them to the cache. For requests, we care 819 * about those for us and those for our proxies. We reply to both, 820 * and in the case of requests for us we add the requester to the arp 821 * cache. 822 */ 823 824 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 825 if (sip == 0) { 826 if (arp->ar_op == htons(ARPOP_REQUEST) && 827 inet_addr_type(tip) == RTN_LOCAL && 828 !arp_ignore(in_dev,dev,sip,tip)) 829 arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr); 830 goto out; 831 } 832 833 if (arp->ar_op == htons(ARPOP_REQUEST) && 834 ip_route_input(skb, tip, sip, 0, dev) == 0) { 835 836 rt = (struct rtable*)skb->dst; 837 addr_type = rt->rt_type; 838 839 if (addr_type == RTN_LOCAL) { 840 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 841 if (n) { 842 int dont_send = 0; 843 844 if (!dont_send) 845 dont_send |= arp_ignore(in_dev,dev,sip,tip); 846 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 847 dont_send |= arp_filter(sip,tip,dev); 848 if (!dont_send) 849 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 850 851 neigh_release(n); 852 } 853 goto out; 854 } else if (IN_DEV_FORWARD(in_dev)) { 855 if ((rt->rt_flags&RTCF_DNAT) || 856 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev && 857 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) { 858 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 859 if (n) 860 neigh_release(n); 861 862 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 863 skb->pkt_type == PACKET_HOST || 864 in_dev->arp_parms->proxy_delay == 0) { 865 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 866 } else { 867 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); 868 in_dev_put(in_dev); 869 return 0; 870 } 871 goto out; 872 } 873 } 874 } 875 876 /* Update our ARP tables */ 877 878 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 879 880#ifdef CONFIG_IP_ACCEPT_UNSOLICITED_ARP 881 /* Unsolicited ARP is not accepted by default. 882 It is possible, that this option should be enabled for some 883 devices (strip is candidate) 884 */ 885 if (n == NULL && 886 arp->ar_op == htons(ARPOP_REPLY) && 887 inet_addr_type(sip) == RTN_UNICAST) 888 n = __neigh_lookup(&arp_tbl, &sip, dev, -1); 889#endif 890 891 if (n) { 892 int state = NUD_REACHABLE; 893 int override; 894 895 /* If several different ARP replies follows back-to-back, 896 use the FIRST one. It is possible, if several proxy 897 agents are active. Taking the first reply prevents 898 arp trashing and chooses the fastest router. 899 */ 900 override = time_after(jiffies, n->updated + n->parms->locktime); 901 902 /* Broadcast replies and request packets 903 do not assert neighbour reachability. 904 */ 905 if (arp->ar_op != htons(ARPOP_REPLY) || 906 skb->pkt_type != PACKET_HOST) 907 state = NUD_STALE; 908 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0); 909 neigh_release(n); 910 } 911 912out: 913 if (in_dev) 914 in_dev_put(in_dev); 915 kfree_skb(skb); 916 return 0; 917} 918 919static void parp_redo(struct sk_buff *skb) 920{ 921 arp_process(skb); 922} 923 924 925/* 926 * Receive an arp request from the device layer. 927 */ 928 929int arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) 930{ 931 struct arphdr *arp; 932 933 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 934 if (!pskb_may_pull(skb, (sizeof(struct arphdr) + 935 (2 * dev->addr_len) + 936 (2 * sizeof(u32))))) 937 goto freeskb; 938 939 arp = skb->nh.arph; 940 if (arp->ar_hln != dev->addr_len || 941 dev->flags & IFF_NOARP || 942 skb->pkt_type == PACKET_OTHERHOST || 943 skb->pkt_type == PACKET_LOOPBACK || 944 arp->ar_pln != 4) 945 goto freeskb; 946 947 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 948 goto out_of_mem; 949 950 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 951 952 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 953 954freeskb: 955 kfree_skb(skb); 956out_of_mem: 957 return 0; 958} 959 960/* 961 * User level interface (ioctl) 962 */ 963 964/* 965 * Set (create) an ARP cache entry. 966 */ 967 968static int arp_req_set(struct arpreq *r, struct net_device * dev) 969{ 970 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 971 struct neighbour *neigh; 972 int err; 973 974 if (r->arp_flags&ATF_PUBL) { 975 u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; 976 if (mask && mask != 0xFFFFFFFF) 977 return -EINVAL; 978 if (!dev && (r->arp_flags & ATF_COM)) { 979 dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data); 980 if (!dev) 981 return -ENODEV; 982 } 983 if (mask) { 984 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL) 985 return -ENOBUFS; 986 return 0; 987 } 988 if (dev == NULL) { 989 ipv4_devconf.proxy_arp = 1; 990 return 0; 991 } 992 if (__in_dev_get(dev)) { 993 __in_dev_get(dev)->cnf.proxy_arp = 1; 994 return 0; 995 } 996 return -ENXIO; 997 } 998 999 if (r->arp_flags & ATF_PERM) 1000 r->arp_flags |= ATF_COM; 1001 if (dev == NULL) { 1002 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1003 .tos = RTO_ONLINK } } }; 1004 struct rtable * rt; 1005 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1006 return err; 1007 dev = rt->u.dst.dev; 1008 ip_rt_put(rt); 1009 if (!dev) 1010 return -EINVAL; 1011 } 1012 switch (dev->type) { 1013#ifdef CONFIG_FDDI 1014 case ARPHRD_FDDI: 1015 /* 1016 * According to RFC 1390, FDDI devices should accept ARP 1017 * hardware types of 1 (Ethernet). However, to be more 1018 * robust, we'll accept hardware types of either 1 (Ethernet) 1019 * or 6 (IEEE 802.2). 1020 */ 1021 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1022 r->arp_ha.sa_family != ARPHRD_ETHER && 1023 r->arp_ha.sa_family != ARPHRD_IEEE802) 1024 return -EINVAL; 1025 break; 1026#endif 1027 default: 1028 if (r->arp_ha.sa_family != dev->type) 1029 return -EINVAL; 1030 break; 1031 } 1032 1033 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1034 err = PTR_ERR(neigh); 1035 if (!IS_ERR(neigh)) { 1036 unsigned state = NUD_STALE; 1037 if (r->arp_flags & ATF_PERM) 1038 state = NUD_PERMANENT; 1039 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ? 1040 r->arp_ha.sa_data : NULL, state, 1041 NEIGH_UPDATE_F_OVERRIDE| 1042 NEIGH_UPDATE_F_ADMIN); 1043 neigh_release(neigh); 1044 } 1045 return err; 1046} 1047 1048static unsigned arp_state_to_flags(struct neighbour *neigh) 1049{ 1050 unsigned flags = 0; 1051 if (neigh->nud_state&NUD_PERMANENT) 1052 flags = ATF_PERM|ATF_COM; 1053 else if (neigh->nud_state&NUD_VALID) 1054 flags = ATF_COM; 1055 return flags; 1056} 1057 1058/* 1059 * Get an ARP cache entry. 1060 */ 1061 1062static int arp_req_get(struct arpreq *r, struct net_device *dev) 1063{ 1064 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1065 struct neighbour *neigh; 1066 int err = -ENXIO; 1067 1068 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1069 if (neigh) { 1070 read_lock_bh(&neigh->lock); 1071 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1072 r->arp_flags = arp_state_to_flags(neigh); 1073 read_unlock_bh(&neigh->lock); 1074 r->arp_ha.sa_family = dev->type; 1075 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1076 neigh_release(neigh); 1077 err = 0; 1078 } 1079 return err; 1080} 1081 1082static int arp_req_delete(struct arpreq *r, struct net_device * dev) 1083{ 1084 int err; 1085 u32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1086 struct neighbour *neigh; 1087 1088 if (r->arp_flags & ATF_PUBL) { 1089 u32 mask = 1090 ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1091 if (mask == 0xFFFFFFFF) 1092 return pneigh_delete(&arp_tbl, &ip, dev); 1093 if (mask == 0) { 1094 if (dev == NULL) { 1095 ipv4_devconf.proxy_arp = 0; 1096 return 0; 1097 } 1098 if (__in_dev_get(dev)) { 1099 __in_dev_get(dev)->cnf.proxy_arp = 0; 1100 return 0; 1101 } 1102 return -ENXIO; 1103 } 1104 return -EINVAL; 1105 } 1106 1107 if (dev == NULL) { 1108 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1109 .tos = RTO_ONLINK } } }; 1110 struct rtable * rt; 1111 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1112 return err; 1113 dev = rt->u.dst.dev; 1114 ip_rt_put(rt); 1115 if (!dev) 1116 return -EINVAL; 1117 } 1118 err = -ENXIO; 1119 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1120 if (neigh) { 1121 if (neigh->nud_state&~NUD_NOARP) 1122 err = neigh_update(neigh, NULL, NUD_FAILED, 1123 NEIGH_UPDATE_F_OVERRIDE| 1124 NEIGH_UPDATE_F_ADMIN); 1125 neigh_release(neigh); 1126 } 1127 return err; 1128} 1129 1130/* 1131 * Handle an ARP layer I/O control request. 1132 */ 1133 1134int arp_ioctl(unsigned int cmd, void __user *arg) 1135{ 1136 int err; 1137 struct arpreq r; 1138 struct net_device *dev = NULL; 1139 1140 switch (cmd) { 1141 case SIOCDARP: 1142 case SIOCSARP: 1143 if (!capable(CAP_NET_ADMIN)) 1144 return -EPERM; 1145 case SIOCGARP: 1146 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1147 if (err) 1148 return -EFAULT; 1149 break; 1150 default: 1151 return -EINVAL; 1152 } 1153 1154 if (r.arp_pa.sa_family != AF_INET) 1155 return -EPFNOSUPPORT; 1156 1157 if (!(r.arp_flags & ATF_PUBL) && 1158 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) 1159 return -EINVAL; 1160 if (!(r.arp_flags & ATF_NETMASK)) 1161 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1162 htonl(0xFFFFFFFFUL); 1163 rtnl_lock(); 1164 if (r.arp_dev[0]) { 1165 err = -ENODEV; 1166 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL) 1167 goto out; 1168 1169 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1170 if (!r.arp_ha.sa_family) 1171 r.arp_ha.sa_family = dev->type; 1172 err = -EINVAL; 1173 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1174 goto out; 1175 } else if (cmd == SIOCGARP) { 1176 err = -ENODEV; 1177 goto out; 1178 } 1179 1180 switch(cmd) { 1181 case SIOCDARP: 1182 err = arp_req_delete(&r, dev); 1183 break; 1184 case SIOCSARP: 1185 err = arp_req_set(&r, dev); 1186 break; 1187 case SIOCGARP: 1188 err = arp_req_get(&r, dev); 1189 if (!err && copy_to_user(arg, &r, sizeof(r))) 1190 err = -EFAULT; 1191 break; 1192 } 1193out: 1194 rtnl_unlock(); 1195 return err; 1196} 1197 1198static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1199{ 1200 struct net_device *dev = ptr; 1201 1202 switch (event) { 1203 case NETDEV_CHANGEADDR: 1204 neigh_changeaddr(&arp_tbl, dev); 1205 rt_cache_flush(0); 1206 break; 1207 default: 1208 break; 1209 } 1210 1211 return NOTIFY_DONE; 1212} 1213 1214static struct notifier_block arp_netdev_notifier = { 1215 .notifier_call = arp_netdev_event, 1216}; 1217 1218/* Note, that it is not on notifier chain. 1219 It is necessary, that this routine was called after route cache will be 1220 flushed. 1221 */ 1222void arp_ifdown(struct net_device *dev) 1223{ 1224 neigh_ifdown(&arp_tbl, dev); 1225} 1226 1227 1228/* 1229 * Called once on startup. 1230 */ 1231 1232static struct packet_type arp_packet_type = { 1233 .type = __constant_htons(ETH_P_ARP), 1234 .func = arp_rcv, 1235}; 1236 1237static int arp_proc_init(void); 1238 1239void __init arp_init(void) 1240{ 1241 neigh_table_init(&arp_tbl); 1242 1243 dev_add_pack(&arp_packet_type); 1244 arp_proc_init(); 1245#ifdef CONFIG_SYSCTL 1246 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, 1247 NET_IPV4_NEIGH, "ipv4", NULL, NULL); 1248#endif 1249 register_netdevice_notifier(&arp_netdev_notifier); 1250} 1251 1252#ifdef CONFIG_PROC_FS 1253#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1254 1255/* ------------------------------------------------------------------------ */ 1256/* 1257 * ax25 -> ASCII conversion 1258 */ 1259static char *ax2asc2(ax25_address *a, char *buf) 1260{ 1261 char c, *s; 1262 int n; 1263 1264 for (n = 0, s = buf; n < 6; n++) { 1265 c = (a->ax25_call[n] >> 1) & 0x7F; 1266 1267 if (c != ' ') *s++ = c; 1268 } 1269 1270 *s++ = '-'; 1271 1272 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { 1273 *s++ = '1'; 1274 n -= 10; 1275 } 1276 1277 *s++ = n + '0'; 1278 *s++ = '\0'; 1279 1280 if (*buf == '\0' || *buf == '-') 1281 return "*"; 1282 1283 return buf; 1284 1285} 1286#endif /* CONFIG_AX25 */ 1287 1288#define HBUFFERLEN 30 1289 1290static void arp_format_neigh_entry(struct seq_file *seq, 1291 struct neighbour *n) 1292{ 1293 char hbuffer[HBUFFERLEN]; 1294 const char hexbuf[] = "0123456789ABCDEF"; 1295 int k, j; 1296 char tbuf[16]; 1297 struct net_device *dev = n->dev; 1298 int hatype = dev->type; 1299 1300 read_lock(&n->lock); 1301 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1302#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1303 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1304 ax2asc2((ax25_address *)n->ha, hbuffer); 1305 else { 1306#endif 1307 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1308 hbuffer[k++] = hexbuf[(n->ha[j] >> 4) & 15]; 1309 hbuffer[k++] = hexbuf[n->ha[j] & 15]; 1310 hbuffer[k++] = ':'; 1311 } 1312 hbuffer[--k] = 0; 1313#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1314 } 1315#endif 1316 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key)); 1317 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1318 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1319 read_unlock(&n->lock); 1320} 1321 1322static void arp_format_pneigh_entry(struct seq_file *seq, 1323 struct pneigh_entry *n) 1324{ 1325 struct net_device *dev = n->dev; 1326 int hatype = dev ? dev->type : 0; 1327 char tbuf[16]; 1328 1329 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key)); 1330 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1331 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1332 dev ? dev->name : "*"); 1333} 1334 1335static int arp_seq_show(struct seq_file *seq, void *v) 1336{ 1337 if (v == SEQ_START_TOKEN) { 1338 seq_puts(seq, "IP address HW type Flags " 1339 "HW address Mask Device\n"); 1340 } else { 1341 struct neigh_seq_state *state = seq->private; 1342 1343 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1344 arp_format_pneigh_entry(seq, v); 1345 else 1346 arp_format_neigh_entry(seq, v); 1347 } 1348 1349 return 0; 1350} 1351 1352static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1353{ 1354 /* Don't want to confuse "arp -a" w/ magic entries, 1355 * so we tell the generic iterator to skip NUD_NOARP. 1356 */ 1357 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1358} 1359 1360/* ------------------------------------------------------------------------ */ 1361 1362static struct seq_operations arp_seq_ops = { 1363 .start = arp_seq_start, 1364 .next = neigh_seq_next, 1365 .stop = neigh_seq_stop, 1366 .show = arp_seq_show, 1367}; 1368 1369static int arp_seq_open(struct inode *inode, struct file *file) 1370{ 1371 struct seq_file *seq; 1372 int rc = -ENOMEM; 1373 struct neigh_seq_state *s = kmalloc(sizeof(*s), GFP_KERNEL); 1374 1375 if (!s) 1376 goto out; 1377 1378 memset(s, 0, sizeof(*s)); 1379 rc = seq_open(file, &arp_seq_ops); 1380 if (rc) 1381 goto out_kfree; 1382 1383 seq = file->private_data; 1384 seq->private = s; 1385out: 1386 return rc; 1387out_kfree: 1388 kfree(s); 1389 goto out; 1390} 1391 1392static struct file_operations arp_seq_fops = { 1393 .owner = THIS_MODULE, 1394 .open = arp_seq_open, 1395 .read = seq_read, 1396 .llseek = seq_lseek, 1397 .release = seq_release_private, 1398}; 1399 1400static int __init arp_proc_init(void) 1401{ 1402 if (!proc_net_fops_create("arp", S_IRUGO, &arp_seq_fops)) 1403 return -ENOMEM; 1404 return 0; 1405} 1406 1407#else /* CONFIG_PROC_FS */ 1408 1409static int __init arp_proc_init(void) 1410{ 1411 return 0; 1412} 1413 1414#endif /* CONFIG_PROC_FS */ 1415 1416EXPORT_SYMBOL(arp_broken_ops); 1417EXPORT_SYMBOL(arp_find); 1418EXPORT_SYMBOL(arp_rcv); 1419EXPORT_SYMBOL(arp_create); 1420EXPORT_SYMBOL(arp_xmit); 1421EXPORT_SYMBOL(arp_send); 1422EXPORT_SYMBOL(arp_tbl); 1423 1424#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 1425EXPORT_SYMBOL(clip_tbl_hook); 1426#endif 1427