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/capability.h> 83 #include <linux/config.h> 84 #include <linux/socket.h> 85 #include <linux/sockios.h> 86 #include <linux/errno.h> 87 #include <linux/in.h> 88 #include <linux/mm.h> 89 #include <linux/inet.h> 90 #include <linux/inetdevice.h> 91 #include <linux/netdevice.h> 92 #include <linux/etherdevice.h> 93 #include <linux/fddidevice.h> 94 #include <linux/if_arp.h> 95 #include <linux/trdevice.h> 96 #include <linux/skbuff.h> 97 #include <linux/proc_fs.h> 98 #include <linux/seq_file.h> 99 #include <linux/stat.h> 100 #include <linux/init.h> 101 #include <linux/net.h> 102 #include <linux/rcupdate.h> 103 #include <linux/jhash.h> 104 #ifdef CONFIG_SYSCTL 105 #include <linux/sysctl.h> 106 #endif 107 108 #include <net/ip.h> 109 #include <net/icmp.h> 110 #include <net/route.h> 111 #include <net/protocol.h> 112 #include <net/tcp.h> 113 #include <net/sock.h> 114 #include <net/arp.h> 115 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 116 #include <net/ax25.h> 117 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 118 #include <net/netrom.h> 119 #endif 120 #endif 121 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 122 #include <net/atmclip.h> 123 struct neigh_table *clip_tbl_hook; 124 #endif 125 126 #include <asm/system.h> 127 #include <asm/uaccess.h> 128 129 #include <linux/netfilter_arp.h> 130 131 /* 132 * Interface to generic neighbour cache. 133 */ 134 static u32 arp_hash(const void *pkey, const struct net_device *dev); 135 static int arp_constructor(struct neighbour *neigh); 136 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 137 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 138 static void parp_redo(struct sk_buff *skb); 139 140 static struct neigh_ops arp_generic_ops = { 141 .family = AF_INET, 142 .solicit = arp_solicit, 143 .error_report = arp_error_report, 144 .output = neigh_resolve_output, 145 .connected_output = neigh_connected_output, 146 .hh_output = dev_queue_xmit, 147 .queue_xmit = dev_queue_xmit, 148 }; 149 150 static struct neigh_ops arp_hh_ops = { 151 .family = AF_INET, 152 .solicit = arp_solicit, 153 .error_report = arp_error_report, 154 .output = neigh_resolve_output, 155 .connected_output = neigh_resolve_output, 156 .hh_output = dev_queue_xmit, 157 .queue_xmit = dev_queue_xmit, 158 }; 159 160 static struct neigh_ops arp_direct_ops = { 161 .family = AF_INET, 162 .output = dev_queue_xmit, 163 .connected_output = dev_queue_xmit, 164 .hh_output = dev_queue_xmit, 165 .queue_xmit = dev_queue_xmit, 166 }; 167 168 struct neigh_ops arp_broken_ops = { 169 .family = AF_INET, 170 .solicit = arp_solicit, 171 .error_report = arp_error_report, 172 .output = neigh_compat_output, 173 .connected_output = neigh_compat_output, 174 .hh_output = dev_queue_xmit, 175 .queue_xmit = dev_queue_xmit, 176 }; 177 178 struct neigh_table arp_tbl = { 179 .family = AF_INET, 180 .entry_size = sizeof(struct neighbour) + 4, 181 .key_len = 4, 182 .hash = arp_hash, 183 .constructor = arp_constructor, 184 .proxy_redo = parp_redo, 185 .id = "arp_cache", 186 .parms = { 187 .tbl = &arp_tbl, 188 .base_reachable_time = 30 * HZ, 189 .retrans_time = 1 * HZ, 190 .gc_staletime = 60 * HZ, 191 .reachable_time = 30 * HZ, 192 .delay_probe_time = 5 * HZ, 193 .queue_len = 3, 194 .ucast_probes = 3, 195 .mcast_probes = 3, 196 .anycast_delay = 1 * HZ, 197 .proxy_delay = (8 * HZ) / 10, 198 .proxy_qlen = 64, 199 .locktime = 1 * HZ, 200 }, 201 .gc_interval = 30 * HZ, 202 .gc_thresh1 = 128, 203 .gc_thresh2 = 512, 204 .gc_thresh3 = 1024, 205 }; 206 207 int arp_mc_map(u32 addr, u8 *haddr, struct net_device *dev, int dir) 208 { 209 switch (dev->type) { 210 case ARPHRD_ETHER: 211 case ARPHRD_FDDI: 212 case ARPHRD_IEEE802: 213 ip_eth_mc_map(addr, haddr); 214 return 0; 215 case ARPHRD_IEEE802_TR: 216 ip_tr_mc_map(addr, haddr); 217 return 0; 218 case ARPHRD_INFINIBAND: 219 ip_ib_mc_map(addr, haddr); 220 return 0; 221 default: 222 if (dir) { 223 memcpy(haddr, dev->broadcast, dev->addr_len); 224 return 0; 225 } 226 } 227 return -EINVAL; 228 } 229 230 231 static u32 arp_hash(const void *pkey, const struct net_device *dev) 232 { 233 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd); 234 } 235 236 static int arp_constructor(struct neighbour *neigh) 237 { 238 u32 addr = *(u32*)neigh->primary_key; 239 struct net_device *dev = neigh->dev; 240 struct in_device *in_dev; 241 struct neigh_parms *parms; 242 243 neigh->type = inet_addr_type(addr); 244 245 rcu_read_lock(); 246 in_dev = __in_dev_get_rcu(dev); 247 if (in_dev == NULL) { 248 rcu_read_unlock(); 249 return -EINVAL; 250 } 251 252 parms = in_dev->arp_parms; 253 __neigh_parms_put(neigh->parms); 254 neigh->parms = neigh_parms_clone(parms); 255 rcu_read_unlock(); 256 257 if (dev->hard_header == NULL) { 258 neigh->nud_state = NUD_NOARP; 259 neigh->ops = &arp_direct_ops; 260 neigh->output = neigh->ops->queue_xmit; 261 } else { 262 /* Good devices (checked by reading texts, but only Ethernet is 263 tested) 264 265 ARPHRD_ETHER: (ethernet, apfddi) 266 ARPHRD_FDDI: (fddi) 267 ARPHRD_IEEE802: (tr) 268 ARPHRD_METRICOM: (strip) 269 ARPHRD_ARCNET: 270 etc. etc. etc. 271 272 ARPHRD_IPDDP will also work, if author repairs it. 273 I did not it, because this driver does not work even 274 in old paradigm. 275 */ 276 277 #if 1 278 /* So... these "amateur" devices are hopeless. 279 The only thing, that I can say now: 280 It is very sad that we need to keep ugly obsolete 281 code to make them happy. 282 283 They should be moved to more reasonable state, now 284 they use rebuild_header INSTEAD OF hard_start_xmit!!! 285 Besides that, they are sort of out of date 286 (a lot of redundant clones/copies, useless in 2.1), 287 I wonder why people believe that they work. 288 */ 289 switch (dev->type) { 290 default: 291 break; 292 case ARPHRD_ROSE: 293 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 294 case ARPHRD_AX25: 295 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 296 case ARPHRD_NETROM: 297 #endif 298 neigh->ops = &arp_broken_ops; 299 neigh->output = neigh->ops->output; 300 return 0; 301 #endif 302 ;} 303 #endif 304 if (neigh->type == RTN_MULTICAST) { 305 neigh->nud_state = NUD_NOARP; 306 arp_mc_map(addr, neigh->ha, dev, 1); 307 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { 308 neigh->nud_state = NUD_NOARP; 309 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 310 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) { 311 neigh->nud_state = NUD_NOARP; 312 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 313 } 314 if (dev->hard_header_cache) 315 neigh->ops = &arp_hh_ops; 316 else 317 neigh->ops = &arp_generic_ops; 318 if (neigh->nud_state&NUD_VALID) 319 neigh->output = neigh->ops->connected_output; 320 else 321 neigh->output = neigh->ops->output; 322 } 323 return 0; 324 } 325 326 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 327 { 328 dst_link_failure(skb); 329 kfree_skb(skb); 330 } 331 332 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 333 { 334 u32 saddr = 0; 335 u8 *dst_ha = NULL; 336 struct net_device *dev = neigh->dev; 337 u32 target = *(u32*)neigh->primary_key; 338 int probes = atomic_read(&neigh->probes); 339 struct in_device *in_dev = in_dev_get(dev); 340 341 if (!in_dev) 342 return; 343 344 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 345 default: 346 case 0: /* By default announce any local IP */ 347 if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL) 348 saddr = skb->nh.iph->saddr; 349 break; 350 case 1: /* Restrict announcements of saddr in same subnet */ 351 if (!skb) 352 break; 353 saddr = skb->nh.iph->saddr; 354 if (inet_addr_type(saddr) == RTN_LOCAL) { 355 /* saddr should be known to target */ 356 if (inet_addr_onlink(in_dev, target, saddr)) 357 break; 358 } 359 saddr = 0; 360 break; 361 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 362 break; 363 } 364 365 if (in_dev) 366 in_dev_put(in_dev); 367 if (!saddr) 368 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 369 370 if ((probes -= neigh->parms->ucast_probes) < 0) { 371 if (!(neigh->nud_state&NUD_VALID)) 372 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n"); 373 dst_ha = neigh->ha; 374 read_lock_bh(&neigh->lock); 375 } else if ((probes -= neigh->parms->app_probes) < 0) { 376 #ifdef CONFIG_ARPD 377 neigh_app_ns(neigh); 378 #endif 379 return; 380 } 381 382 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 383 dst_ha, dev->dev_addr, NULL); 384 if (dst_ha) 385 read_unlock_bh(&neigh->lock); 386 } 387 388 static int arp_ignore(struct in_device *in_dev, struct net_device *dev, 389 u32 sip, u32 tip) 390 { 391 int scope; 392 393 switch (IN_DEV_ARP_IGNORE(in_dev)) { 394 case 0: /* Reply, the tip is already validated */ 395 return 0; 396 case 1: /* Reply only if tip is configured on the incoming interface */ 397 sip = 0; 398 scope = RT_SCOPE_HOST; 399 break; 400 case 2: /* 401 * Reply only if tip is configured on the incoming interface 402 * and is in same subnet as sip 403 */ 404 scope = RT_SCOPE_HOST; 405 break; 406 case 3: /* Do not reply for scope host addresses */ 407 sip = 0; 408 scope = RT_SCOPE_LINK; 409 dev = NULL; 410 break; 411 case 4: /* Reserved */ 412 case 5: 413 case 6: 414 case 7: 415 return 0; 416 case 8: /* Do not reply */ 417 return 1; 418 default: 419 return 0; 420 } 421 return !inet_confirm_addr(dev, sip, tip, scope); 422 } 423 424 static int arp_filter(__u32 sip, __u32 tip, struct net_device *dev) 425 { 426 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip, 427 .saddr = tip } } }; 428 struct rtable *rt; 429 int flag = 0; 430 /*unsigned long now; */ 431 432 if (ip_route_output_key(&rt, &fl) < 0) 433 return 1; 434 if (rt->u.dst.dev != dev) { 435 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER); 436 flag = 1; 437 } 438 ip_rt_put(rt); 439 return flag; 440 } 441 442 /* OBSOLETE FUNCTIONS */ 443 444 /* 445 * Find an arp mapping in the cache. If not found, post a request. 446 * 447 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 448 * even if it exists. It is supposed that skb->dev was mangled 449 * by a virtual device (eql, shaper). Nobody but broken devices 450 * is allowed to use this function, it is scheduled to be removed. --ANK 451 */ 452 453 static int arp_set_predefined(int addr_hint, unsigned char * haddr, u32 paddr, struct net_device * dev) 454 { 455 switch (addr_hint) { 456 case RTN_LOCAL: 457 printk(KERN_DEBUG "ARP: arp called for own IP address\n"); 458 memcpy(haddr, dev->dev_addr, dev->addr_len); 459 return 1; 460 case RTN_MULTICAST: 461 arp_mc_map(paddr, haddr, dev, 1); 462 return 1; 463 case RTN_BROADCAST: 464 memcpy(haddr, dev->broadcast, dev->addr_len); 465 return 1; 466 } 467 return 0; 468 } 469 470 471 int arp_find(unsigned char *haddr, struct sk_buff *skb) 472 { 473 struct net_device *dev = skb->dev; 474 u32 paddr; 475 struct neighbour *n; 476 477 if (!skb->dst) { 478 printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); 479 kfree_skb(skb); 480 return 1; 481 } 482 483 paddr = ((struct rtable*)skb->dst)->rt_gateway; 484 485 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev)) 486 return 0; 487 488 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 489 490 if (n) { 491 n->used = jiffies; 492 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { 493 read_lock_bh(&n->lock); 494 memcpy(haddr, n->ha, dev->addr_len); 495 read_unlock_bh(&n->lock); 496 neigh_release(n); 497 return 0; 498 } 499 neigh_release(n); 500 } else 501 kfree_skb(skb); 502 return 1; 503 } 504 505 /* END OF OBSOLETE FUNCTIONS */ 506 507 int arp_bind_neighbour(struct dst_entry *dst) 508 { 509 struct net_device *dev = dst->dev; 510 struct neighbour *n = dst->neighbour; 511 512 if (dev == NULL) 513 return -EINVAL; 514 if (n == NULL) { 515 u32 nexthop = ((struct rtable*)dst)->rt_gateway; 516 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT)) 517 nexthop = 0; 518 n = __neigh_lookup_errno( 519 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 520 dev->type == ARPHRD_ATM ? clip_tbl_hook : 521 #endif 522 &arp_tbl, &nexthop, dev); 523 if (IS_ERR(n)) 524 return PTR_ERR(n); 525 dst->neighbour = n; 526 } 527 return 0; 528 } 529 530 /* 531 * Check if we can use proxy ARP for this path 532 */ 533 534 static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt) 535 { 536 struct in_device *out_dev; 537 int imi, omi = -1; 538 539 if (!IN_DEV_PROXY_ARP(in_dev)) 540 return 0; 541 542 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0) 543 return 1; 544 if (imi == -1) 545 return 0; 546 547 /* place to check for proxy_arp for routes */ 548 549 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) { 550 omi = IN_DEV_MEDIUM_ID(out_dev); 551 in_dev_put(out_dev); 552 } 553 return (omi != imi && omi != -1); 554 } 555 556 /* 557 * Interface to link layer: send routine and receive handler. 558 */ 559 560 /* 561 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 562 * message. 563 */ 564 struct sk_buff *arp_create(int type, int ptype, u32 dest_ip, 565 struct net_device *dev, u32 src_ip, 566 unsigned char *dest_hw, unsigned char *src_hw, 567 unsigned char *target_hw) 568 { 569 struct sk_buff *skb; 570 struct arphdr *arp; 571 unsigned char *arp_ptr; 572 573 /* 574 * Allocate a buffer 575 */ 576 577 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) 578 + LL_RESERVED_SPACE(dev), GFP_ATOMIC); 579 if (skb == NULL) 580 return NULL; 581 582 skb_reserve(skb, LL_RESERVED_SPACE(dev)); 583 skb->nh.raw = skb->data; 584 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4)); 585 skb->dev = dev; 586 skb->protocol = htons(ETH_P_ARP); 587 if (src_hw == NULL) 588 src_hw = dev->dev_addr; 589 if (dest_hw == NULL) 590 dest_hw = dev->broadcast; 591 592 /* 593 * Fill the device header for the ARP frame 594 */ 595 if (dev->hard_header && 596 dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0) 597 goto out; 598 599 /* 600 * Fill out the arp protocol part. 601 * 602 * The arp hardware type should match the device type, except for FDDI, 603 * which (according to RFC 1390) should always equal 1 (Ethernet). 604 */ 605 /* 606 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 607 * DIX code for the protocol. Make these device structure fields. 608 */ 609 switch (dev->type) { 610 default: 611 arp->ar_hrd = htons(dev->type); 612 arp->ar_pro = htons(ETH_P_IP); 613 break; 614 615 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 616 case ARPHRD_AX25: 617 arp->ar_hrd = htons(ARPHRD_AX25); 618 arp->ar_pro = htons(AX25_P_IP); 619 break; 620 621 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 622 case ARPHRD_NETROM: 623 arp->ar_hrd = htons(ARPHRD_NETROM); 624 arp->ar_pro = htons(AX25_P_IP); 625 break; 626 #endif 627 #endif 628 629 #ifdef CONFIG_FDDI 630 case ARPHRD_FDDI: 631 arp->ar_hrd = htons(ARPHRD_ETHER); 632 arp->ar_pro = htons(ETH_P_IP); 633 break; 634 #endif 635 #ifdef CONFIG_TR 636 case ARPHRD_IEEE802_TR: 637 arp->ar_hrd = htons(ARPHRD_IEEE802); 638 arp->ar_pro = htons(ETH_P_IP); 639 break; 640 #endif 641 } 642 643 arp->ar_hln = dev->addr_len; 644 arp->ar_pln = 4; 645 arp->ar_op = htons(type); 646 647 arp_ptr=(unsigned char *)(arp+1); 648 649 memcpy(arp_ptr, src_hw, dev->addr_len); 650 arp_ptr+=dev->addr_len; 651 memcpy(arp_ptr, &src_ip,4); 652 arp_ptr+=4; 653 if (target_hw != NULL) 654 memcpy(arp_ptr, target_hw, dev->addr_len); 655 else 656 memset(arp_ptr, 0, dev->addr_len); 657 arp_ptr+=dev->addr_len; 658 memcpy(arp_ptr, &dest_ip, 4); 659 660 return skb; 661 662 out: 663 kfree_skb(skb); 664 return NULL; 665 } 666 667 /* 668 * Send an arp packet. 669 */ 670 void arp_xmit(struct sk_buff *skb) 671 { 672 /* Send it off, maybe filter it using firewalling first. */ 673 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 674 } 675 676 /* 677 * Create and send an arp packet. 678 */ 679 void arp_send(int type, int ptype, u32 dest_ip, 680 struct net_device *dev, u32 src_ip, 681 unsigned char *dest_hw, unsigned char *src_hw, 682 unsigned char *target_hw) 683 { 684 struct sk_buff *skb; 685 686 /* 687 * No arp on this interface. 688 */ 689 690 if (dev->flags&IFF_NOARP) 691 return; 692 693 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 694 dest_hw, src_hw, target_hw); 695 if (skb == NULL) { 696 return; 697 } 698 699 arp_xmit(skb); 700 } 701 702 /* 703 * Process an arp request. 704 */ 705 706 static int arp_process(struct sk_buff *skb) 707 { 708 struct net_device *dev = skb->dev; 709 struct in_device *in_dev = in_dev_get(dev); 710 struct arphdr *arp; 711 unsigned char *arp_ptr; 712 struct rtable *rt; 713 unsigned char *sha, *tha; 714 u32 sip, tip; 715 u16 dev_type = dev->type; 716 int addr_type; 717 struct neighbour *n; 718 719 /* arp_rcv below verifies the ARP header and verifies the device 720 * is ARP'able. 721 */ 722 723 if (in_dev == NULL) 724 goto out; 725 726 arp = skb->nh.arph; 727 728 switch (dev_type) { 729 default: 730 if (arp->ar_pro != htons(ETH_P_IP) || 731 htons(dev_type) != arp->ar_hrd) 732 goto out; 733 break; 734 #ifdef CONFIG_NET_ETHERNET 735 case ARPHRD_ETHER: 736 #endif 737 #ifdef CONFIG_TR 738 case ARPHRD_IEEE802_TR: 739 #endif 740 #ifdef CONFIG_FDDI 741 case ARPHRD_FDDI: 742 #endif 743 #ifdef CONFIG_NET_FC 744 case ARPHRD_IEEE802: 745 #endif 746 #if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_TR) || \ 747 defined(CONFIG_FDDI) || defined(CONFIG_NET_FC) 748 /* 749 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 750 * devices, according to RFC 2625) devices will accept ARP 751 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 752 * This is the case also of FDDI, where the RFC 1390 says that 753 * FDDI devices should accept ARP hardware of (1) Ethernet, 754 * however, to be more robust, we'll accept both 1 (Ethernet) 755 * or 6 (IEEE 802.2) 756 */ 757 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 758 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 759 arp->ar_pro != htons(ETH_P_IP)) 760 goto out; 761 break; 762 #endif 763 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 764 case ARPHRD_AX25: 765 if (arp->ar_pro != htons(AX25_P_IP) || 766 arp->ar_hrd != htons(ARPHRD_AX25)) 767 goto out; 768 break; 769 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 770 case ARPHRD_NETROM: 771 if (arp->ar_pro != htons(AX25_P_IP) || 772 arp->ar_hrd != htons(ARPHRD_NETROM)) 773 goto out; 774 break; 775 #endif 776 #endif 777 } 778 779 /* Understand only these message types */ 780 781 if (arp->ar_op != htons(ARPOP_REPLY) && 782 arp->ar_op != htons(ARPOP_REQUEST)) 783 goto out; 784 785 /* 786 * Extract fields 787 */ 788 arp_ptr= (unsigned char *)(arp+1); 789 sha = arp_ptr; 790 arp_ptr += dev->addr_len; 791 memcpy(&sip, arp_ptr, 4); 792 arp_ptr += 4; 793 tha = arp_ptr; 794 arp_ptr += dev->addr_len; 795 memcpy(&tip, arp_ptr, 4); 796 /* 797 * Check for bad requests for 127.x.x.x and requests for multicast 798 * addresses. If this is one such, delete it. 799 */ 800 if (LOOPBACK(tip) || MULTICAST(tip)) 801 goto out; 802 803 /* 804 * Special case: We must set Frame Relay source Q.922 address 805 */ 806 if (dev_type == ARPHRD_DLCI) 807 sha = dev->broadcast; 808 809 /* 810 * Process entry. The idea here is we want to send a reply if it is a 811 * request for us or if it is a request for someone else that we hold 812 * a proxy for. We want to add an entry to our cache if it is a reply 813 * to us or if it is a request for our address. 814 * (The assumption for this last is that if someone is requesting our 815 * address, they are probably intending to talk to us, so it saves time 816 * if we cache their address. Their address is also probably not in 817 * our cache, since ours is not in their cache.) 818 * 819 * Putting this another way, we only care about replies if they are to 820 * us, in which case we add them to the cache. For requests, we care 821 * about those for us and those for our proxies. We reply to both, 822 * and in the case of requests for us we add the requester to the arp 823 * cache. 824 */ 825 826 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 827 if (sip == 0) { 828 if (arp->ar_op == htons(ARPOP_REQUEST) && 829 inet_addr_type(tip) == RTN_LOCAL && 830 !arp_ignore(in_dev,dev,sip,tip)) 831 arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr); 832 goto out; 833 } 834 835 if (arp->ar_op == htons(ARPOP_REQUEST) && 836 ip_route_input(skb, tip, sip, 0, dev) == 0) { 837 838 rt = (struct rtable*)skb->dst; 839 addr_type = rt->rt_type; 840 841 if (addr_type == RTN_LOCAL) { 842 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 843 if (n) { 844 int dont_send = 0; 845 846 if (!dont_send) 847 dont_send |= arp_ignore(in_dev,dev,sip,tip); 848 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 849 dont_send |= arp_filter(sip,tip,dev); 850 if (!dont_send) 851 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 852 853 neigh_release(n); 854 } 855 goto out; 856 } else if (IN_DEV_FORWARD(in_dev)) { 857 if ((rt->rt_flags&RTCF_DNAT) || 858 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev && 859 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) { 860 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 861 if (n) 862 neigh_release(n); 863 864 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 865 skb->pkt_type == PACKET_HOST || 866 in_dev->arp_parms->proxy_delay == 0) { 867 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 868 } else { 869 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); 870 in_dev_put(in_dev); 871 return 0; 872 } 873 goto out; 874 } 875 } 876 } 877 878 /* Update our ARP tables */ 879 880 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 881 882 if (ipv4_devconf.arp_accept) { 883 /* Unsolicited ARP is not accepted by default. 884 It is possible, that this option should be enabled for some 885 devices (strip is candidate) 886 */ 887 if (n == NULL && 888 arp->ar_op == htons(ARPOP_REPLY) && 889 inet_addr_type(sip) == RTN_UNICAST) 890 n = __neigh_lookup(&arp_tbl, &sip, dev, -1); 891 } 892 893 if (n) { 894 int state = NUD_REACHABLE; 895 int override; 896 897 /* If several different ARP replies follows back-to-back, 898 use the FIRST one. It is possible, if several proxy 899 agents are active. Taking the first reply prevents 900 arp trashing and chooses the fastest router. 901 */ 902 override = time_after(jiffies, n->updated + n->parms->locktime); 903 904 /* Broadcast replies and request packets 905 do not assert neighbour reachability. 906 */ 907 if (arp->ar_op != htons(ARPOP_REPLY) || 908 skb->pkt_type != PACKET_HOST) 909 state = NUD_STALE; 910 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0); 911 neigh_release(n); 912 } 913 914 out: 915 if (in_dev) 916 in_dev_put(in_dev); 917 kfree_skb(skb); 918 return 0; 919 } 920 921 static void parp_redo(struct sk_buff *skb) 922 { 923 arp_process(skb); 924 } 925 926 927 /* 928 * Receive an arp request from the device layer. 929 */ 930 931 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 932 struct packet_type *pt, struct net_device *orig_dev) 933 { 934 struct arphdr *arp; 935 936 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 937 if (!pskb_may_pull(skb, (sizeof(struct arphdr) + 938 (2 * dev->addr_len) + 939 (2 * sizeof(u32))))) 940 goto freeskb; 941 942 arp = skb->nh.arph; 943 if (arp->ar_hln != dev->addr_len || 944 dev->flags & IFF_NOARP || 945 skb->pkt_type == PACKET_OTHERHOST || 946 skb->pkt_type == PACKET_LOOPBACK || 947 arp->ar_pln != 4) 948 goto freeskb; 949 950 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 951 goto out_of_mem; 952 953 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 954 955 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 956 957 freeskb: 958 kfree_skb(skb); 959 out_of_mem: 960 return 0; 961 } 962 963 /* 964 * User level interface (ioctl) 965 */ 966 967 /* 968 * Set (create) an ARP cache entry. 969 */ 970 971 static int arp_req_set(struct arpreq *r, struct net_device * dev) 972 { 973 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 974 struct neighbour *neigh; 975 int err; 976 977 if (r->arp_flags&ATF_PUBL) { 978 u32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; 979 if (mask && mask != 0xFFFFFFFF) 980 return -EINVAL; 981 if (!dev && (r->arp_flags & ATF_COM)) { 982 dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data); 983 if (!dev) 984 return -ENODEV; 985 } 986 if (mask) { 987 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL) 988 return -ENOBUFS; 989 return 0; 990 } 991 if (dev == NULL) { 992 ipv4_devconf.proxy_arp = 1; 993 return 0; 994 } 995 if (__in_dev_get_rtnl(dev)) { 996 __in_dev_get_rtnl(dev)->cnf.proxy_arp = 1; 997 return 0; 998 } 999 return -ENXIO; 1000 } 1001 1002 if (r->arp_flags & ATF_PERM) 1003 r->arp_flags |= ATF_COM; 1004 if (dev == NULL) { 1005 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1006 .tos = RTO_ONLINK } } }; 1007 struct rtable * rt; 1008 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1009 return err; 1010 dev = rt->u.dst.dev; 1011 ip_rt_put(rt); 1012 if (!dev) 1013 return -EINVAL; 1014 } 1015 switch (dev->type) { 1016 #ifdef CONFIG_FDDI 1017 case ARPHRD_FDDI: 1018 /* 1019 * According to RFC 1390, FDDI devices should accept ARP 1020 * hardware types of 1 (Ethernet). However, to be more 1021 * robust, we'll accept hardware types of either 1 (Ethernet) 1022 * or 6 (IEEE 802.2). 1023 */ 1024 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1025 r->arp_ha.sa_family != ARPHRD_ETHER && 1026 r->arp_ha.sa_family != ARPHRD_IEEE802) 1027 return -EINVAL; 1028 break; 1029 #endif 1030 default: 1031 if (r->arp_ha.sa_family != dev->type) 1032 return -EINVAL; 1033 break; 1034 } 1035 1036 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1037 err = PTR_ERR(neigh); 1038 if (!IS_ERR(neigh)) { 1039 unsigned state = NUD_STALE; 1040 if (r->arp_flags & ATF_PERM) 1041 state = NUD_PERMANENT; 1042 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ? 1043 r->arp_ha.sa_data : NULL, state, 1044 NEIGH_UPDATE_F_OVERRIDE| 1045 NEIGH_UPDATE_F_ADMIN); 1046 neigh_release(neigh); 1047 } 1048 return err; 1049 } 1050 1051 static unsigned arp_state_to_flags(struct neighbour *neigh) 1052 { 1053 unsigned flags = 0; 1054 if (neigh->nud_state&NUD_PERMANENT) 1055 flags = ATF_PERM|ATF_COM; 1056 else if (neigh->nud_state&NUD_VALID) 1057 flags = ATF_COM; 1058 return flags; 1059 } 1060 1061 /* 1062 * Get an ARP cache entry. 1063 */ 1064 1065 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1066 { 1067 u32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1068 struct neighbour *neigh; 1069 int err = -ENXIO; 1070 1071 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1072 if (neigh) { 1073 read_lock_bh(&neigh->lock); 1074 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1075 r->arp_flags = arp_state_to_flags(neigh); 1076 read_unlock_bh(&neigh->lock); 1077 r->arp_ha.sa_family = dev->type; 1078 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1079 neigh_release(neigh); 1080 err = 0; 1081 } 1082 return err; 1083 } 1084 1085 static int arp_req_delete(struct arpreq *r, struct net_device * dev) 1086 { 1087 int err; 1088 u32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1089 struct neighbour *neigh; 1090 1091 if (r->arp_flags & ATF_PUBL) { 1092 u32 mask = 1093 ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1094 if (mask == 0xFFFFFFFF) 1095 return pneigh_delete(&arp_tbl, &ip, dev); 1096 if (mask == 0) { 1097 if (dev == NULL) { 1098 ipv4_devconf.proxy_arp = 0; 1099 return 0; 1100 } 1101 if (__in_dev_get_rtnl(dev)) { 1102 __in_dev_get_rtnl(dev)->cnf.proxy_arp = 0; 1103 return 0; 1104 } 1105 return -ENXIO; 1106 } 1107 return -EINVAL; 1108 } 1109 1110 if (dev == NULL) { 1111 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1112 .tos = RTO_ONLINK } } }; 1113 struct rtable * rt; 1114 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1115 return err; 1116 dev = rt->u.dst.dev; 1117 ip_rt_put(rt); 1118 if (!dev) 1119 return -EINVAL; 1120 } 1121 err = -ENXIO; 1122 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1123 if (neigh) { 1124 if (neigh->nud_state&~NUD_NOARP) 1125 err = neigh_update(neigh, NULL, NUD_FAILED, 1126 NEIGH_UPDATE_F_OVERRIDE| 1127 NEIGH_UPDATE_F_ADMIN); 1128 neigh_release(neigh); 1129 } 1130 return err; 1131 } 1132 1133 /* 1134 * Handle an ARP layer I/O control request. 1135 */ 1136 1137 int arp_ioctl(unsigned int cmd, void __user *arg) 1138 { 1139 int err; 1140 struct arpreq r; 1141 struct net_device *dev = NULL; 1142 1143 switch (cmd) { 1144 case SIOCDARP: 1145 case SIOCSARP: 1146 if (!capable(CAP_NET_ADMIN)) 1147 return -EPERM; 1148 case SIOCGARP: 1149 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1150 if (err) 1151 return -EFAULT; 1152 break; 1153 default: 1154 return -EINVAL; 1155 } 1156 1157 if (r.arp_pa.sa_family != AF_INET) 1158 return -EPFNOSUPPORT; 1159 1160 if (!(r.arp_flags & ATF_PUBL) && 1161 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) 1162 return -EINVAL; 1163 if (!(r.arp_flags & ATF_NETMASK)) 1164 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1165 htonl(0xFFFFFFFFUL); 1166 rtnl_lock(); 1167 if (r.arp_dev[0]) { 1168 err = -ENODEV; 1169 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL) 1170 goto out; 1171 1172 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1173 if (!r.arp_ha.sa_family) 1174 r.arp_ha.sa_family = dev->type; 1175 err = -EINVAL; 1176 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1177 goto out; 1178 } else if (cmd == SIOCGARP) { 1179 err = -ENODEV; 1180 goto out; 1181 } 1182 1183 switch(cmd) { 1184 case SIOCDARP: 1185 err = arp_req_delete(&r, dev); 1186 break; 1187 case SIOCSARP: 1188 err = arp_req_set(&r, dev); 1189 break; 1190 case SIOCGARP: 1191 err = arp_req_get(&r, dev); 1192 if (!err && copy_to_user(arg, &r, sizeof(r))) 1193 err = -EFAULT; 1194 break; 1195 } 1196 out: 1197 rtnl_unlock(); 1198 return err; 1199 } 1200 1201 static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1202 { 1203 struct net_device *dev = ptr; 1204 1205 switch (event) { 1206 case NETDEV_CHANGEADDR: 1207 neigh_changeaddr(&arp_tbl, dev); 1208 rt_cache_flush(0); 1209 break; 1210 default: 1211 break; 1212 } 1213 1214 return NOTIFY_DONE; 1215 } 1216 1217 static struct notifier_block arp_netdev_notifier = { 1218 .notifier_call = arp_netdev_event, 1219 }; 1220 1221 /* Note, that it is not on notifier chain. 1222 It is necessary, that this routine was called after route cache will be 1223 flushed. 1224 */ 1225 void arp_ifdown(struct net_device *dev) 1226 { 1227 neigh_ifdown(&arp_tbl, dev); 1228 } 1229 1230 1231 /* 1232 * Called once on startup. 1233 */ 1234 1235 static struct packet_type arp_packet_type = { 1236 .type = __constant_htons(ETH_P_ARP), 1237 .func = arp_rcv, 1238 }; 1239 1240 static int arp_proc_init(void); 1241 1242 void __init arp_init(void) 1243 { 1244 neigh_table_init(&arp_tbl); 1245 1246 dev_add_pack(&arp_packet_type); 1247 arp_proc_init(); 1248 #ifdef CONFIG_SYSCTL 1249 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, 1250 NET_IPV4_NEIGH, "ipv4", NULL, NULL); 1251 #endif 1252 register_netdevice_notifier(&arp_netdev_notifier); 1253 } 1254 1255 #ifdef CONFIG_PROC_FS 1256 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1257 1258 /* ------------------------------------------------------------------------ */ 1259 /* 1260 * ax25 -> ASCII conversion 1261 */ 1262 static char *ax2asc2(ax25_address *a, char *buf) 1263 { 1264 char c, *s; 1265 int n; 1266 1267 for (n = 0, s = buf; n < 6; n++) { 1268 c = (a->ax25_call[n] >> 1) & 0x7F; 1269 1270 if (c != ' ') *s++ = c; 1271 } 1272 1273 *s++ = '-'; 1274 1275 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { 1276 *s++ = '1'; 1277 n -= 10; 1278 } 1279 1280 *s++ = n + '0'; 1281 *s++ = '\0'; 1282 1283 if (*buf == '\0' || *buf == '-') 1284 return "*"; 1285 1286 return buf; 1287 1288 } 1289 #endif /* CONFIG_AX25 */ 1290 1291 #define HBUFFERLEN 30 1292 1293 static void arp_format_neigh_entry(struct seq_file *seq, 1294 struct neighbour *n) 1295 { 1296 char hbuffer[HBUFFERLEN]; 1297 const char hexbuf[] = "0123456789ABCDEF"; 1298 int k, j; 1299 char tbuf[16]; 1300 struct net_device *dev = n->dev; 1301 int hatype = dev->type; 1302 1303 read_lock(&n->lock); 1304 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1305 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1306 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1307 ax2asc2((ax25_address *)n->ha, hbuffer); 1308 else { 1309 #endif 1310 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1311 hbuffer[k++] = hexbuf[(n->ha[j] >> 4) & 15]; 1312 hbuffer[k++] = hexbuf[n->ha[j] & 15]; 1313 hbuffer[k++] = ':'; 1314 } 1315 hbuffer[--k] = 0; 1316 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1317 } 1318 #endif 1319 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key)); 1320 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1321 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1322 read_unlock(&n->lock); 1323 } 1324 1325 static void arp_format_pneigh_entry(struct seq_file *seq, 1326 struct pneigh_entry *n) 1327 { 1328 struct net_device *dev = n->dev; 1329 int hatype = dev ? dev->type : 0; 1330 char tbuf[16]; 1331 1332 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key)); 1333 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1334 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1335 dev ? dev->name : "*"); 1336 } 1337 1338 static int arp_seq_show(struct seq_file *seq, void *v) 1339 { 1340 if (v == SEQ_START_TOKEN) { 1341 seq_puts(seq, "IP address HW type Flags " 1342 "HW address Mask Device\n"); 1343 } else { 1344 struct neigh_seq_state *state = seq->private; 1345 1346 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1347 arp_format_pneigh_entry(seq, v); 1348 else 1349 arp_format_neigh_entry(seq, v); 1350 } 1351 1352 return 0; 1353 } 1354 1355 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1356 { 1357 /* Don't want to confuse "arp -a" w/ magic entries, 1358 * so we tell the generic iterator to skip NUD_NOARP. 1359 */ 1360 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1361 } 1362 1363 /* ------------------------------------------------------------------------ */ 1364 1365 static struct seq_operations arp_seq_ops = { 1366 .start = arp_seq_start, 1367 .next = neigh_seq_next, 1368 .stop = neigh_seq_stop, 1369 .show = arp_seq_show, 1370 }; 1371 1372 static int arp_seq_open(struct inode *inode, struct file *file) 1373 { 1374 struct seq_file *seq; 1375 int rc = -ENOMEM; 1376 struct neigh_seq_state *s = kmalloc(sizeof(*s), GFP_KERNEL); 1377 1378 if (!s) 1379 goto out; 1380 1381 memset(s, 0, sizeof(*s)); 1382 rc = seq_open(file, &arp_seq_ops); 1383 if (rc) 1384 goto out_kfree; 1385 1386 seq = file->private_data; 1387 seq->private = s; 1388 out: 1389 return rc; 1390 out_kfree: 1391 kfree(s); 1392 goto out; 1393 } 1394 1395 static struct file_operations arp_seq_fops = { 1396 .owner = THIS_MODULE, 1397 .open = arp_seq_open, 1398 .read = seq_read, 1399 .llseek = seq_lseek, 1400 .release = seq_release_private, 1401 }; 1402 1403 static int __init arp_proc_init(void) 1404 { 1405 if (!proc_net_fops_create("arp", S_IRUGO, &arp_seq_fops)) 1406 return -ENOMEM; 1407 return 0; 1408 } 1409 1410 #else /* CONFIG_PROC_FS */ 1411 1412 static int __init arp_proc_init(void) 1413 { 1414 return 0; 1415 } 1416 1417 #endif /* CONFIG_PROC_FS */ 1418 1419 EXPORT_SYMBOL(arp_broken_ops); 1420 EXPORT_SYMBOL(arp_find); 1421 EXPORT_SYMBOL(arp_create); 1422 EXPORT_SYMBOL(arp_xmit); 1423 EXPORT_SYMBOL(arp_send); 1424 EXPORT_SYMBOL(arp_tbl); 1425 1426 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 1427 EXPORT_SYMBOL(clip_tbl_hook); 1428 #endif 1429