1 /* linux/net/ipv4/arp.c 2 * 3 * Version: $Id: arp.c,v 1.99 2001/08/30 22:55:42 davem Exp $ 4 * 5 * Copyright (C) 1994 by Florian La Roche 6 * 7 * This module implements the Address Resolution Protocol ARP (RFC 826), 8 * which is used to convert IP addresses (or in the future maybe other 9 * high-level addresses) into a low-level hardware address (like an Ethernet 10 * address). 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * Fixes: 18 * Alan Cox : Removed the Ethernet assumptions in 19 * Florian's code 20 * Alan Cox : Fixed some small errors in the ARP 21 * logic 22 * Alan Cox : Allow >4K in /proc 23 * Alan Cox : Make ARP add its own protocol entry 24 * Ross Martin : Rewrote arp_rcv() and arp_get_info() 25 * Stephen Henson : Add AX25 support to arp_get_info() 26 * Alan Cox : Drop data when a device is downed. 27 * Alan Cox : Use init_timer(). 28 * Alan Cox : Double lock fixes. 29 * Martin Seine : Move the arphdr structure 30 * to if_arp.h for compatibility. 31 * with BSD based programs. 32 * Andrew Tridgell : Added ARP netmask code and 33 * re-arranged proxy handling. 34 * Alan Cox : Changed to use notifiers. 35 * Niibe Yutaka : Reply for this device or proxies only. 36 * Alan Cox : Don't proxy across hardware types! 37 * Jonathan Naylor : Added support for NET/ROM. 38 * Mike Shaver : RFC1122 checks. 39 * Jonathan Naylor : Only lookup the hardware address for 40 * the correct hardware type. 41 * Germano Caronni : Assorted subtle races. 42 * Craig Schlenter : Don't modify permanent entry 43 * during arp_rcv. 44 * Russ Nelson : Tidied up a few bits. 45 * Alexey Kuznetsov: Major changes to caching and behaviour, 46 * eg intelligent arp probing and 47 * generation 48 * of host down events. 49 * Alan Cox : Missing unlock in device events. 50 * Eckes : ARP ioctl control errors. 51 * Alexey Kuznetsov: Arp free fix. 52 * Manuel Rodriguez: Gratuitous ARP. 53 * Jonathan Layes : Added arpd support through kerneld 54 * message queue (960314) 55 * Mike Shaver : /proc/sys/net/ipv4/arp_* support 56 * Mike McLagan : Routing by source 57 * Stuart Cheshire : Metricom and grat arp fixes 58 * *** FOR 2.1 clean this up *** 59 * Lawrence V. Stefani: (08/12/96) Added FDDI support. 60 * Alan Cox : Took the AP1000 nasty FDDI hack and 61 * folded into the mainstream FDDI code. 62 * Ack spit, Linus how did you allow that 63 * one in... 64 * Jes Sorensen : Make FDDI work again in 2.1.x and 65 * clean up the APFDDI & gen. FDDI bits. 66 * Alexey Kuznetsov: new arp state machine; 67 * now it is in net/core/neighbour.c. 68 * Krzysztof Halasa: Added Frame Relay ARP support. 69 * Arnaldo C. Melo : convert /proc/net/arp to seq_file 70 * Shmulik Hen: Split arp_send to arp_create and 71 * arp_xmit so intermediate drivers like 72 * bonding can change the skb before 73 * sending (e.g. insert 8021q tag). 74 * Harald Welte : convert to make use of jenkins hash 75 */ 76 77 #include <linux/module.h> 78 #include <linux/types.h> 79 #include <linux/string.h> 80 #include <linux/kernel.h> 81 #include <linux/capability.h> 82 #include <linux/socket.h> 83 #include <linux/sockios.h> 84 #include <linux/errno.h> 85 #include <linux/in.h> 86 #include <linux/mm.h> 87 #include <linux/inet.h> 88 #include <linux/inetdevice.h> 89 #include <linux/netdevice.h> 90 #include <linux/etherdevice.h> 91 #include <linux/fddidevice.h> 92 #include <linux/if_arp.h> 93 #include <linux/trdevice.h> 94 #include <linux/skbuff.h> 95 #include <linux/proc_fs.h> 96 #include <linux/seq_file.h> 97 #include <linux/stat.h> 98 #include <linux/init.h> 99 #include <linux/net.h> 100 #include <linux/rcupdate.h> 101 #include <linux/jhash.h> 102 #ifdef CONFIG_SYSCTL 103 #include <linux/sysctl.h> 104 #endif 105 106 #include <net/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> 121 struct 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 */ 132 static u32 arp_hash(const void *pkey, const struct net_device *dev); 133 static int arp_constructor(struct neighbour *neigh); 134 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 135 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 136 static void parp_redo(struct sk_buff *skb); 137 138 static 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 }; 147 148 static 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 }; 157 158 static 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 }; 165 166 struct 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 }; 175 176 struct 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 }; 204 205 int arp_mc_map(__be32 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 } 227 228 229 static 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 } 233 234 static int arp_constructor(struct neighbour *neigh) 235 { 236 __be32 addr = *(__be32*)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 = __in_dev_get_rcu(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 } 323 324 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 325 { 326 dst_link_failure(skb); 327 kfree_skb(skb); 328 } 329 330 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 331 { 332 __be32 saddr = 0; 333 u8 *dst_ha = NULL; 334 struct net_device *dev = neigh->dev; 335 __be32 target = *(__be32*)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(ip_hdr(skb)->saddr) == RTN_LOCAL) 346 saddr = ip_hdr(skb)->saddr; 347 break; 348 case 1: /* Restrict announcements of saddr in same subnet */ 349 if (!skb) 350 break; 351 saddr = ip_hdr(skb)->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 } 385 386 static int arp_ignore(struct in_device *in_dev, struct net_device *dev, 387 __be32 sip, __be32 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 } 421 422 static int arp_filter(__be32 sip, __be32 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 */ 450 451 static int arp_set_predefined(int addr_hint, unsigned char * haddr, __be32 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 } 467 468 469 int arp_find(unsigned char *haddr, struct sk_buff *skb) 470 { 471 struct net_device *dev = skb->dev; 472 __be32 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 */ 504 505 int 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 __be32 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 */ 531 532 static 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 */ 562 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 563 struct net_device *dev, __be32 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_reset_network_header(skb); 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; 659 660 out: 661 kfree_skb(skb); 662 return NULL; 663 } 664 665 /* 666 * Send an arp packet. 667 */ 668 void 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 */ 677 void arp_send(int type, int ptype, __be32 dest_ip, 678 struct net_device *dev, __be32 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 */ 703 704 static 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 __be32 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 = arp_hdr(skb); 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 if (IPV4_DEVCONF_ALL(ARP_ACCEPT)) { 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 } 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 } 911 912 out: 913 if (in_dev) 914 in_dev_put(in_dev); 915 kfree_skb(skb); 916 return 0; 917 } 918 919 static 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 */ 928 929 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 930 struct packet_type *pt, struct net_device *orig_dev) 931 { 932 struct arphdr *arp; 933 934 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 935 if (!pskb_may_pull(skb, (sizeof(struct arphdr) + 936 (2 * dev->addr_len) + 937 (2 * sizeof(u32))))) 938 goto freeskb; 939 940 arp = arp_hdr(skb); 941 if (arp->ar_hln != dev->addr_len || 942 dev->flags & IFF_NOARP || 943 skb->pkt_type == PACKET_OTHERHOST || 944 skb->pkt_type == PACKET_LOOPBACK || 945 arp->ar_pln != 4) 946 goto freeskb; 947 948 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 949 goto out_of_mem; 950 951 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 952 953 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 954 955 freeskb: 956 kfree_skb(skb); 957 out_of_mem: 958 return 0; 959 } 960 961 /* 962 * User level interface (ioctl) 963 */ 964 965 /* 966 * Set (create) an ARP cache entry. 967 */ 968 969 static int arp_req_set(struct arpreq *r, struct net_device * dev) 970 { 971 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 972 struct neighbour *neigh; 973 int err; 974 975 if (r->arp_flags&ATF_PUBL) { 976 __be32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; 977 if (mask && mask != htonl(0xFFFFFFFF)) 978 return -EINVAL; 979 if (!dev && (r->arp_flags & ATF_COM)) { 980 dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data); 981 if (!dev) 982 return -ENODEV; 983 } 984 if (mask) { 985 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL) 986 return -ENOBUFS; 987 return 0; 988 } 989 if (dev == NULL) { 990 IPV4_DEVCONF_ALL(PROXY_ARP) = 1; 991 return 0; 992 } 993 if (__in_dev_get_rtnl(dev)) { 994 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, 1); 995 return 0; 996 } 997 return -ENXIO; 998 } 999 1000 if (r->arp_flags & ATF_PERM) 1001 r->arp_flags |= ATF_COM; 1002 if (dev == NULL) { 1003 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1004 .tos = RTO_ONLINK } } }; 1005 struct rtable * rt; 1006 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1007 return err; 1008 dev = rt->u.dst.dev; 1009 ip_rt_put(rt); 1010 if (!dev) 1011 return -EINVAL; 1012 } 1013 switch (dev->type) { 1014 #ifdef CONFIG_FDDI 1015 case ARPHRD_FDDI: 1016 /* 1017 * According to RFC 1390, FDDI devices should accept ARP 1018 * hardware types of 1 (Ethernet). However, to be more 1019 * robust, we'll accept hardware types of either 1 (Ethernet) 1020 * or 6 (IEEE 802.2). 1021 */ 1022 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1023 r->arp_ha.sa_family != ARPHRD_ETHER && 1024 r->arp_ha.sa_family != ARPHRD_IEEE802) 1025 return -EINVAL; 1026 break; 1027 #endif 1028 default: 1029 if (r->arp_ha.sa_family != dev->type) 1030 return -EINVAL; 1031 break; 1032 } 1033 1034 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1035 err = PTR_ERR(neigh); 1036 if (!IS_ERR(neigh)) { 1037 unsigned state = NUD_STALE; 1038 if (r->arp_flags & ATF_PERM) 1039 state = NUD_PERMANENT; 1040 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ? 1041 r->arp_ha.sa_data : NULL, state, 1042 NEIGH_UPDATE_F_OVERRIDE| 1043 NEIGH_UPDATE_F_ADMIN); 1044 neigh_release(neigh); 1045 } 1046 return err; 1047 } 1048 1049 static unsigned arp_state_to_flags(struct neighbour *neigh) 1050 { 1051 unsigned flags = 0; 1052 if (neigh->nud_state&NUD_PERMANENT) 1053 flags = ATF_PERM|ATF_COM; 1054 else if (neigh->nud_state&NUD_VALID) 1055 flags = ATF_COM; 1056 return flags; 1057 } 1058 1059 /* 1060 * Get an ARP cache entry. 1061 */ 1062 1063 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1064 { 1065 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1066 struct neighbour *neigh; 1067 int err = -ENXIO; 1068 1069 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1070 if (neigh) { 1071 read_lock_bh(&neigh->lock); 1072 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1073 r->arp_flags = arp_state_to_flags(neigh); 1074 read_unlock_bh(&neigh->lock); 1075 r->arp_ha.sa_family = dev->type; 1076 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1077 neigh_release(neigh); 1078 err = 0; 1079 } 1080 return err; 1081 } 1082 1083 static int arp_req_delete(struct arpreq *r, struct net_device * dev) 1084 { 1085 int err; 1086 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1087 struct neighbour *neigh; 1088 1089 if (r->arp_flags & ATF_PUBL) { 1090 __be32 mask = 1091 ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1092 if (mask == htonl(0xFFFFFFFF)) 1093 return pneigh_delete(&arp_tbl, &ip, dev); 1094 if (mask == 0) { 1095 if (dev == NULL) { 1096 IPV4_DEVCONF_ALL(PROXY_ARP) = 0; 1097 return 0; 1098 } 1099 if (__in_dev_get_rtnl(dev)) { 1100 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), 1101 PROXY_ARP, 0); 1102 return 0; 1103 } 1104 return -ENXIO; 1105 } 1106 return -EINVAL; 1107 } 1108 1109 if (dev == NULL) { 1110 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1111 .tos = RTO_ONLINK } } }; 1112 struct rtable * rt; 1113 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1114 return err; 1115 dev = rt->u.dst.dev; 1116 ip_rt_put(rt); 1117 if (!dev) 1118 return -EINVAL; 1119 } 1120 err = -ENXIO; 1121 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1122 if (neigh) { 1123 if (neigh->nud_state&~NUD_NOARP) 1124 err = neigh_update(neigh, NULL, NUD_FAILED, 1125 NEIGH_UPDATE_F_OVERRIDE| 1126 NEIGH_UPDATE_F_ADMIN); 1127 neigh_release(neigh); 1128 } 1129 return err; 1130 } 1131 1132 /* 1133 * Handle an ARP layer I/O control request. 1134 */ 1135 1136 int arp_ioctl(unsigned int cmd, void __user *arg) 1137 { 1138 int err; 1139 struct arpreq r; 1140 struct net_device *dev = NULL; 1141 1142 switch (cmd) { 1143 case SIOCDARP: 1144 case SIOCSARP: 1145 if (!capable(CAP_NET_ADMIN)) 1146 return -EPERM; 1147 case SIOCGARP: 1148 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1149 if (err) 1150 return -EFAULT; 1151 break; 1152 default: 1153 return -EINVAL; 1154 } 1155 1156 if (r.arp_pa.sa_family != AF_INET) 1157 return -EPFNOSUPPORT; 1158 1159 if (!(r.arp_flags & ATF_PUBL) && 1160 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) 1161 return -EINVAL; 1162 if (!(r.arp_flags & ATF_NETMASK)) 1163 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1164 htonl(0xFFFFFFFFUL); 1165 rtnl_lock(); 1166 if (r.arp_dev[0]) { 1167 err = -ENODEV; 1168 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL) 1169 goto out; 1170 1171 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1172 if (!r.arp_ha.sa_family) 1173 r.arp_ha.sa_family = dev->type; 1174 err = -EINVAL; 1175 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1176 goto out; 1177 } else if (cmd == SIOCGARP) { 1178 err = -ENODEV; 1179 goto out; 1180 } 1181 1182 switch (cmd) { 1183 case SIOCDARP: 1184 err = arp_req_delete(&r, dev); 1185 break; 1186 case SIOCSARP: 1187 err = arp_req_set(&r, dev); 1188 break; 1189 case SIOCGARP: 1190 err = arp_req_get(&r, dev); 1191 if (!err && copy_to_user(arg, &r, sizeof(r))) 1192 err = -EFAULT; 1193 break; 1194 } 1195 out: 1196 rtnl_unlock(); 1197 return err; 1198 } 1199 1200 static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1201 { 1202 struct net_device *dev = ptr; 1203 1204 switch (event) { 1205 case NETDEV_CHANGEADDR: 1206 neigh_changeaddr(&arp_tbl, dev); 1207 rt_cache_flush(0); 1208 break; 1209 default: 1210 break; 1211 } 1212 1213 return NOTIFY_DONE; 1214 } 1215 1216 static struct notifier_block arp_netdev_notifier = { 1217 .notifier_call = arp_netdev_event, 1218 }; 1219 1220 /* Note, that it is not on notifier chain. 1221 It is necessary, that this routine was called after route cache will be 1222 flushed. 1223 */ 1224 void arp_ifdown(struct net_device *dev) 1225 { 1226 neigh_ifdown(&arp_tbl, dev); 1227 } 1228 1229 1230 /* 1231 * Called once on startup. 1232 */ 1233 1234 static struct packet_type arp_packet_type = { 1235 .type = __constant_htons(ETH_P_ARP), 1236 .func = arp_rcv, 1237 }; 1238 1239 static int arp_proc_init(void); 1240 1241 void __init arp_init(void) 1242 { 1243 neigh_table_init(&arp_tbl); 1244 1245 dev_add_pack(&arp_packet_type); 1246 arp_proc_init(); 1247 #ifdef CONFIG_SYSCTL 1248 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, 1249 NET_IPV4_NEIGH, "ipv4", NULL, NULL); 1250 #endif 1251 register_netdevice_notifier(&arp_netdev_notifier); 1252 } 1253 1254 #ifdef CONFIG_PROC_FS 1255 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1256 1257 /* ------------------------------------------------------------------------ */ 1258 /* 1259 * ax25 -> ASCII conversion 1260 */ 1261 static char *ax2asc2(ax25_address *a, char *buf) 1262 { 1263 char c, *s; 1264 int n; 1265 1266 for (n = 0, s = buf; n < 6; n++) { 1267 c = (a->ax25_call[n] >> 1) & 0x7F; 1268 1269 if (c != ' ') *s++ = c; 1270 } 1271 1272 *s++ = '-'; 1273 1274 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { 1275 *s++ = '1'; 1276 n -= 10; 1277 } 1278 1279 *s++ = n + '0'; 1280 *s++ = '\0'; 1281 1282 if (*buf == '\0' || *buf == '-') 1283 return "*"; 1284 1285 return buf; 1286 1287 } 1288 #endif /* CONFIG_AX25 */ 1289 1290 #define HBUFFERLEN 30 1291 1292 static void arp_format_neigh_entry(struct seq_file *seq, 1293 struct neighbour *n) 1294 { 1295 char hbuffer[HBUFFERLEN]; 1296 const char hexbuf[] = "0123456789ABCDEF"; 1297 int k, j; 1298 char tbuf[16]; 1299 struct net_device *dev = n->dev; 1300 int hatype = dev->type; 1301 1302 read_lock(&n->lock); 1303 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1304 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1305 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1306 ax2asc2((ax25_address *)n->ha, hbuffer); 1307 else { 1308 #endif 1309 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1310 hbuffer[k++] = hexbuf[(n->ha[j] >> 4) & 15]; 1311 hbuffer[k++] = hexbuf[n->ha[j] & 15]; 1312 hbuffer[k++] = ':'; 1313 } 1314 hbuffer[--k] = 0; 1315 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1316 } 1317 #endif 1318 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key)); 1319 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1320 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1321 read_unlock(&n->lock); 1322 } 1323 1324 static void arp_format_pneigh_entry(struct seq_file *seq, 1325 struct pneigh_entry *n) 1326 { 1327 struct net_device *dev = n->dev; 1328 int hatype = dev ? dev->type : 0; 1329 char tbuf[16]; 1330 1331 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key)); 1332 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1333 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1334 dev ? dev->name : "*"); 1335 } 1336 1337 static int arp_seq_show(struct seq_file *seq, void *v) 1338 { 1339 if (v == SEQ_START_TOKEN) { 1340 seq_puts(seq, "IP address HW type Flags " 1341 "HW address Mask Device\n"); 1342 } else { 1343 struct neigh_seq_state *state = seq->private; 1344 1345 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1346 arp_format_pneigh_entry(seq, v); 1347 else 1348 arp_format_neigh_entry(seq, v); 1349 } 1350 1351 return 0; 1352 } 1353 1354 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1355 { 1356 /* Don't want to confuse "arp -a" w/ magic entries, 1357 * so we tell the generic iterator to skip NUD_NOARP. 1358 */ 1359 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1360 } 1361 1362 /* ------------------------------------------------------------------------ */ 1363 1364 static const struct seq_operations arp_seq_ops = { 1365 .start = arp_seq_start, 1366 .next = neigh_seq_next, 1367 .stop = neigh_seq_stop, 1368 .show = arp_seq_show, 1369 }; 1370 1371 static int arp_seq_open(struct inode *inode, struct file *file) 1372 { 1373 struct seq_file *seq; 1374 int rc = -ENOMEM; 1375 struct neigh_seq_state *s = kzalloc(sizeof(*s), GFP_KERNEL); 1376 1377 if (!s) 1378 goto out; 1379 1380 rc = seq_open(file, &arp_seq_ops); 1381 if (rc) 1382 goto out_kfree; 1383 1384 seq = file->private_data; 1385 seq->private = s; 1386 out: 1387 return rc; 1388 out_kfree: 1389 kfree(s); 1390 goto out; 1391 } 1392 1393 static const struct file_operations arp_seq_fops = { 1394 .owner = THIS_MODULE, 1395 .open = arp_seq_open, 1396 .read = seq_read, 1397 .llseek = seq_lseek, 1398 .release = seq_release_private, 1399 }; 1400 1401 static int __init arp_proc_init(void) 1402 { 1403 if (!proc_net_fops_create("arp", S_IRUGO, &arp_seq_fops)) 1404 return -ENOMEM; 1405 return 0; 1406 } 1407 1408 #else /* CONFIG_PROC_FS */ 1409 1410 static int __init arp_proc_init(void) 1411 { 1412 return 0; 1413 } 1414 1415 #endif /* CONFIG_PROC_FS */ 1416 1417 EXPORT_SYMBOL(arp_broken_ops); 1418 EXPORT_SYMBOL(arp_find); 1419 EXPORT_SYMBOL(arp_create); 1420 EXPORT_SYMBOL(arp_xmit); 1421 EXPORT_SYMBOL(arp_send); 1422 EXPORT_SYMBOL(arp_tbl); 1423 1424 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 1425 EXPORT_SYMBOL(clip_tbl_hook); 1426 #endif 1427