1 /* linux/net/ipv4/arp.c 2 * 3 * Version: $Id: arp.c,v 1.99 2001/08/30 22:55:42 davem Exp $ 4 * 5 * Copyright (C) 1994 by Florian La Roche 6 * 7 * This module implements the Address Resolution Protocol ARP (RFC 826), 8 * which is used to convert IP addresses (or in the future maybe other 9 * high-level addresses) into a low-level hardware address (like an Ethernet 10 * address). 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * Fixes: 18 * Alan Cox : Removed the Ethernet assumptions in 19 * Florian's code 20 * Alan Cox : Fixed some small errors in the ARP 21 * logic 22 * Alan Cox : Allow >4K in /proc 23 * Alan Cox : Make ARP add its own protocol entry 24 * Ross Martin : Rewrote arp_rcv() and arp_get_info() 25 * Stephen Henson : Add AX25 support to arp_get_info() 26 * Alan Cox : Drop data when a device is downed. 27 * Alan Cox : Use init_timer(). 28 * Alan Cox : Double lock fixes. 29 * Martin Seine : Move the arphdr structure 30 * to if_arp.h for compatibility. 31 * with BSD based programs. 32 * Andrew Tridgell : Added ARP netmask code and 33 * re-arranged proxy handling. 34 * Alan Cox : Changed to use notifiers. 35 * Niibe Yutaka : Reply for this device or proxies only. 36 * Alan Cox : Don't proxy across hardware types! 37 * Jonathan Naylor : Added support for NET/ROM. 38 * Mike Shaver : RFC1122 checks. 39 * Jonathan Naylor : Only lookup the hardware address for 40 * the correct hardware type. 41 * Germano Caronni : Assorted subtle races. 42 * Craig Schlenter : Don't modify permanent entry 43 * during arp_rcv. 44 * Russ Nelson : Tidied up a few bits. 45 * Alexey Kuznetsov: Major changes to caching and behaviour, 46 * eg intelligent arp probing and 47 * generation 48 * of host down events. 49 * Alan Cox : Missing unlock in device events. 50 * Eckes : ARP ioctl control errors. 51 * Alexey Kuznetsov: Arp free fix. 52 * Manuel Rodriguez: Gratuitous ARP. 53 * Jonathan Layes : Added arpd support through kerneld 54 * message queue (960314) 55 * Mike Shaver : /proc/sys/net/ipv4/arp_* support 56 * Mike McLagan : Routing by source 57 * Stuart Cheshire : Metricom and grat arp fixes 58 * *** FOR 2.1 clean this up *** 59 * Lawrence V. Stefani: (08/12/96) Added FDDI support. 60 * Alan Cox : Took the AP1000 nasty FDDI hack and 61 * folded into the mainstream FDDI code. 62 * Ack spit, Linus how did you allow that 63 * one in... 64 * Jes Sorensen : Make FDDI work again in 2.1.x and 65 * clean up the APFDDI & gen. FDDI bits. 66 * Alexey Kuznetsov: new arp state machine; 67 * now it is in net/core/neighbour.c. 68 * Krzysztof Halasa: Added Frame Relay ARP support. 69 * Arnaldo C. Melo : convert /proc/net/arp to seq_file 70 * Shmulik Hen: Split arp_send to arp_create and 71 * arp_xmit so intermediate drivers like 72 * bonding can change the skb before 73 * sending (e.g. insert 8021q tag). 74 * Harald Welte : convert to make use of jenkins hash 75 */ 76 77 #include <linux/module.h> 78 #include <linux/types.h> 79 #include <linux/string.h> 80 #include <linux/kernel.h> 81 #include <linux/capability.h> 82 #include <linux/socket.h> 83 #include <linux/sockios.h> 84 #include <linux/errno.h> 85 #include <linux/in.h> 86 #include <linux/mm.h> 87 #include <linux/inet.h> 88 #include <linux/inetdevice.h> 89 #include <linux/netdevice.h> 90 #include <linux/etherdevice.h> 91 #include <linux/fddidevice.h> 92 #include <linux/if_arp.h> 93 #include <linux/trdevice.h> 94 #include <linux/skbuff.h> 95 #include <linux/proc_fs.h> 96 #include <linux/seq_file.h> 97 #include <linux/stat.h> 98 #include <linux/init.h> 99 #include <linux/net.h> 100 #include <linux/rcupdate.h> 101 #include <linux/jhash.h> 102 #ifdef CONFIG_SYSCTL 103 #include <linux/sysctl.h> 104 #endif 105 106 #include <net/net_namespace.h> 107 #include <net/ip.h> 108 #include <net/icmp.h> 109 #include <net/route.h> 110 #include <net/protocol.h> 111 #include <net/tcp.h> 112 #include <net/sock.h> 113 #include <net/arp.h> 114 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 115 #include <net/ax25.h> 116 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 117 #include <net/netrom.h> 118 #endif 119 #endif 120 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 121 #include <net/atmclip.h> 122 struct neigh_table *clip_tbl_hook; 123 #endif 124 125 #include <asm/system.h> 126 #include <asm/uaccess.h> 127 128 #include <linux/netfilter_arp.h> 129 130 /* 131 * Interface to generic neighbour cache. 132 */ 133 static u32 arp_hash(const void *pkey, const struct net_device *dev); 134 static int arp_constructor(struct neighbour *neigh); 135 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 136 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 137 static void parp_redo(struct sk_buff *skb); 138 139 static struct neigh_ops arp_generic_ops = { 140 .family = AF_INET, 141 .solicit = arp_solicit, 142 .error_report = arp_error_report, 143 .output = neigh_resolve_output, 144 .connected_output = neigh_connected_output, 145 .hh_output = dev_queue_xmit, 146 .queue_xmit = dev_queue_xmit, 147 }; 148 149 static struct neigh_ops arp_hh_ops = { 150 .family = AF_INET, 151 .solicit = arp_solicit, 152 .error_report = arp_error_report, 153 .output = neigh_resolve_output, 154 .connected_output = neigh_resolve_output, 155 .hh_output = dev_queue_xmit, 156 .queue_xmit = dev_queue_xmit, 157 }; 158 159 static struct neigh_ops arp_direct_ops = { 160 .family = AF_INET, 161 .output = dev_queue_xmit, 162 .connected_output = dev_queue_xmit, 163 .hh_output = dev_queue_xmit, 164 .queue_xmit = dev_queue_xmit, 165 }; 166 167 struct neigh_ops arp_broken_ops = { 168 .family = AF_INET, 169 .solicit = arp_solicit, 170 .error_report = arp_error_report, 171 .output = neigh_compat_output, 172 .connected_output = neigh_compat_output, 173 .hh_output = dev_queue_xmit, 174 .queue_xmit = dev_queue_xmit, 175 }; 176 177 struct neigh_table arp_tbl = { 178 .family = AF_INET, 179 .entry_size = sizeof(struct neighbour) + 4, 180 .key_len = 4, 181 .hash = arp_hash, 182 .constructor = arp_constructor, 183 .proxy_redo = parp_redo, 184 .id = "arp_cache", 185 .parms = { 186 .tbl = &arp_tbl, 187 .base_reachable_time = 30 * HZ, 188 .retrans_time = 1 * HZ, 189 .gc_staletime = 60 * HZ, 190 .reachable_time = 30 * HZ, 191 .delay_probe_time = 5 * HZ, 192 .queue_len = 3, 193 .ucast_probes = 3, 194 .mcast_probes = 3, 195 .anycast_delay = 1 * HZ, 196 .proxy_delay = (8 * HZ) / 10, 197 .proxy_qlen = 64, 198 .locktime = 1 * HZ, 199 }, 200 .gc_interval = 30 * HZ, 201 .gc_thresh1 = 128, 202 .gc_thresh2 = 512, 203 .gc_thresh3 = 1024, 204 }; 205 206 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 207 { 208 switch (dev->type) { 209 case ARPHRD_ETHER: 210 case ARPHRD_FDDI: 211 case ARPHRD_IEEE802: 212 ip_eth_mc_map(addr, haddr); 213 return 0; 214 case ARPHRD_IEEE802_TR: 215 ip_tr_mc_map(addr, haddr); 216 return 0; 217 case ARPHRD_INFINIBAND: 218 ip_ib_mc_map(addr, haddr); 219 return 0; 220 default: 221 if (dir) { 222 memcpy(haddr, dev->broadcast, dev->addr_len); 223 return 0; 224 } 225 } 226 return -EINVAL; 227 } 228 229 230 static u32 arp_hash(const void *pkey, const struct net_device *dev) 231 { 232 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd); 233 } 234 235 static int arp_constructor(struct neighbour *neigh) 236 { 237 __be32 addr = *(__be32*)neigh->primary_key; 238 struct net_device *dev = neigh->dev; 239 struct in_device *in_dev; 240 struct neigh_parms *parms; 241 242 neigh->type = inet_addr_type(addr); 243 244 rcu_read_lock(); 245 in_dev = __in_dev_get_rcu(dev); 246 if (in_dev == NULL) { 247 rcu_read_unlock(); 248 return -EINVAL; 249 } 250 251 parms = in_dev->arp_parms; 252 __neigh_parms_put(neigh->parms); 253 neigh->parms = neigh_parms_clone(parms); 254 rcu_read_unlock(); 255 256 if (dev->hard_header == NULL) { 257 neigh->nud_state = NUD_NOARP; 258 neigh->ops = &arp_direct_ops; 259 neigh->output = neigh->ops->queue_xmit; 260 } else { 261 /* Good devices (checked by reading texts, but only Ethernet is 262 tested) 263 264 ARPHRD_ETHER: (ethernet, apfddi) 265 ARPHRD_FDDI: (fddi) 266 ARPHRD_IEEE802: (tr) 267 ARPHRD_METRICOM: (strip) 268 ARPHRD_ARCNET: 269 etc. etc. etc. 270 271 ARPHRD_IPDDP will also work, if author repairs it. 272 I did not it, because this driver does not work even 273 in old paradigm. 274 */ 275 276 #if 1 277 /* So... these "amateur" devices are hopeless. 278 The only thing, that I can say now: 279 It is very sad that we need to keep ugly obsolete 280 code to make them happy. 281 282 They should be moved to more reasonable state, now 283 they use rebuild_header INSTEAD OF hard_start_xmit!!! 284 Besides that, they are sort of out of date 285 (a lot of redundant clones/copies, useless in 2.1), 286 I wonder why people believe that they work. 287 */ 288 switch (dev->type) { 289 default: 290 break; 291 case ARPHRD_ROSE: 292 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 293 case ARPHRD_AX25: 294 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 295 case ARPHRD_NETROM: 296 #endif 297 neigh->ops = &arp_broken_ops; 298 neigh->output = neigh->ops->output; 299 return 0; 300 #endif 301 ;} 302 #endif 303 if (neigh->type == RTN_MULTICAST) { 304 neigh->nud_state = NUD_NOARP; 305 arp_mc_map(addr, neigh->ha, dev, 1); 306 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { 307 neigh->nud_state = NUD_NOARP; 308 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 309 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) { 310 neigh->nud_state = NUD_NOARP; 311 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 312 } 313 if (dev->hard_header_cache) 314 neigh->ops = &arp_hh_ops; 315 else 316 neigh->ops = &arp_generic_ops; 317 if (neigh->nud_state&NUD_VALID) 318 neigh->output = neigh->ops->connected_output; 319 else 320 neigh->output = neigh->ops->output; 321 } 322 return 0; 323 } 324 325 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 326 { 327 dst_link_failure(skb); 328 kfree_skb(skb); 329 } 330 331 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 332 { 333 __be32 saddr = 0; 334 u8 *dst_ha = NULL; 335 struct net_device *dev = neigh->dev; 336 __be32 target = *(__be32*)neigh->primary_key; 337 int probes = atomic_read(&neigh->probes); 338 struct in_device *in_dev = in_dev_get(dev); 339 340 if (!in_dev) 341 return; 342 343 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 344 default: 345 case 0: /* By default announce any local IP */ 346 if (skb && inet_addr_type(ip_hdr(skb)->saddr) == RTN_LOCAL) 347 saddr = ip_hdr(skb)->saddr; 348 break; 349 case 1: /* Restrict announcements of saddr in same subnet */ 350 if (!skb) 351 break; 352 saddr = ip_hdr(skb)->saddr; 353 if (inet_addr_type(saddr) == RTN_LOCAL) { 354 /* saddr should be known to target */ 355 if (inet_addr_onlink(in_dev, target, saddr)) 356 break; 357 } 358 saddr = 0; 359 break; 360 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 361 break; 362 } 363 364 if (in_dev) 365 in_dev_put(in_dev); 366 if (!saddr) 367 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 368 369 if ((probes -= neigh->parms->ucast_probes) < 0) { 370 if (!(neigh->nud_state&NUD_VALID)) 371 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n"); 372 dst_ha = neigh->ha; 373 read_lock_bh(&neigh->lock); 374 } else if ((probes -= neigh->parms->app_probes) < 0) { 375 #ifdef CONFIG_ARPD 376 neigh_app_ns(neigh); 377 #endif 378 return; 379 } 380 381 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 382 dst_ha, dev->dev_addr, NULL); 383 if (dst_ha) 384 read_unlock_bh(&neigh->lock); 385 } 386 387 static int arp_ignore(struct in_device *in_dev, struct net_device *dev, 388 __be32 sip, __be32 tip) 389 { 390 int scope; 391 392 switch (IN_DEV_ARP_IGNORE(in_dev)) { 393 case 0: /* Reply, the tip is already validated */ 394 return 0; 395 case 1: /* Reply only if tip is configured on the incoming interface */ 396 sip = 0; 397 scope = RT_SCOPE_HOST; 398 break; 399 case 2: /* 400 * Reply only if tip is configured on the incoming interface 401 * and is in same subnet as sip 402 */ 403 scope = RT_SCOPE_HOST; 404 break; 405 case 3: /* Do not reply for scope host addresses */ 406 sip = 0; 407 scope = RT_SCOPE_LINK; 408 dev = NULL; 409 break; 410 case 4: /* Reserved */ 411 case 5: 412 case 6: 413 case 7: 414 return 0; 415 case 8: /* Do not reply */ 416 return 1; 417 default: 418 return 0; 419 } 420 return !inet_confirm_addr(dev, sip, tip, scope); 421 } 422 423 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 424 { 425 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip, 426 .saddr = tip } } }; 427 struct rtable *rt; 428 int flag = 0; 429 /*unsigned long now; */ 430 431 if (ip_route_output_key(&rt, &fl) < 0) 432 return 1; 433 if (rt->u.dst.dev != dev) { 434 NET_INC_STATS_BH(LINUX_MIB_ARPFILTER); 435 flag = 1; 436 } 437 ip_rt_put(rt); 438 return flag; 439 } 440 441 /* OBSOLETE FUNCTIONS */ 442 443 /* 444 * Find an arp mapping in the cache. If not found, post a request. 445 * 446 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 447 * even if it exists. It is supposed that skb->dev was mangled 448 * by a virtual device (eql, shaper). Nobody but broken devices 449 * is allowed to use this function, it is scheduled to be removed. --ANK 450 */ 451 452 static int arp_set_predefined(int addr_hint, unsigned char * haddr, __be32 paddr, struct net_device * dev) 453 { 454 switch (addr_hint) { 455 case RTN_LOCAL: 456 printk(KERN_DEBUG "ARP: arp called for own IP address\n"); 457 memcpy(haddr, dev->dev_addr, dev->addr_len); 458 return 1; 459 case RTN_MULTICAST: 460 arp_mc_map(paddr, haddr, dev, 1); 461 return 1; 462 case RTN_BROADCAST: 463 memcpy(haddr, dev->broadcast, dev->addr_len); 464 return 1; 465 } 466 return 0; 467 } 468 469 470 int arp_find(unsigned char *haddr, struct sk_buff *skb) 471 { 472 struct net_device *dev = skb->dev; 473 __be32 paddr; 474 struct neighbour *n; 475 476 if (!skb->dst) { 477 printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); 478 kfree_skb(skb); 479 return 1; 480 } 481 482 paddr = ((struct rtable*)skb->dst)->rt_gateway; 483 484 if (arp_set_predefined(inet_addr_type(paddr), haddr, paddr, dev)) 485 return 0; 486 487 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 488 489 if (n) { 490 n->used = jiffies; 491 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { 492 read_lock_bh(&n->lock); 493 memcpy(haddr, n->ha, dev->addr_len); 494 read_unlock_bh(&n->lock); 495 neigh_release(n); 496 return 0; 497 } 498 neigh_release(n); 499 } else 500 kfree_skb(skb); 501 return 1; 502 } 503 504 /* END OF OBSOLETE FUNCTIONS */ 505 506 int arp_bind_neighbour(struct dst_entry *dst) 507 { 508 struct net_device *dev = dst->dev; 509 struct neighbour *n = dst->neighbour; 510 511 if (dev == NULL) 512 return -EINVAL; 513 if (n == NULL) { 514 __be32 nexthop = ((struct rtable*)dst)->rt_gateway; 515 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT)) 516 nexthop = 0; 517 n = __neigh_lookup_errno( 518 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 519 dev->type == ARPHRD_ATM ? clip_tbl_hook : 520 #endif 521 &arp_tbl, &nexthop, dev); 522 if (IS_ERR(n)) 523 return PTR_ERR(n); 524 dst->neighbour = n; 525 } 526 return 0; 527 } 528 529 /* 530 * Check if we can use proxy ARP for this path 531 */ 532 533 static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt) 534 { 535 struct in_device *out_dev; 536 int imi, omi = -1; 537 538 if (!IN_DEV_PROXY_ARP(in_dev)) 539 return 0; 540 541 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0) 542 return 1; 543 if (imi == -1) 544 return 0; 545 546 /* place to check for proxy_arp for routes */ 547 548 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) { 549 omi = IN_DEV_MEDIUM_ID(out_dev); 550 in_dev_put(out_dev); 551 } 552 return (omi != imi && omi != -1); 553 } 554 555 /* 556 * Interface to link layer: send routine and receive handler. 557 */ 558 559 /* 560 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 561 * message. 562 */ 563 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 564 struct net_device *dev, __be32 src_ip, 565 unsigned char *dest_hw, unsigned char *src_hw, 566 unsigned char *target_hw) 567 { 568 struct sk_buff *skb; 569 struct arphdr *arp; 570 unsigned char *arp_ptr; 571 572 /* 573 * Allocate a buffer 574 */ 575 576 skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) 577 + LL_RESERVED_SPACE(dev), GFP_ATOMIC); 578 if (skb == NULL) 579 return NULL; 580 581 skb_reserve(skb, LL_RESERVED_SPACE(dev)); 582 skb_reset_network_header(skb); 583 arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4)); 584 skb->dev = dev; 585 skb->protocol = htons(ETH_P_ARP); 586 if (src_hw == NULL) 587 src_hw = dev->dev_addr; 588 if (dest_hw == NULL) 589 dest_hw = dev->broadcast; 590 591 /* 592 * Fill the device header for the ARP frame 593 */ 594 if (dev->hard_header && 595 dev->hard_header(skb,dev,ptype,dest_hw,src_hw,skb->len) < 0) 596 goto out; 597 598 /* 599 * Fill out the arp protocol part. 600 * 601 * The arp hardware type should match the device type, except for FDDI, 602 * which (according to RFC 1390) should always equal 1 (Ethernet). 603 */ 604 /* 605 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 606 * DIX code for the protocol. Make these device structure fields. 607 */ 608 switch (dev->type) { 609 default: 610 arp->ar_hrd = htons(dev->type); 611 arp->ar_pro = htons(ETH_P_IP); 612 break; 613 614 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 615 case ARPHRD_AX25: 616 arp->ar_hrd = htons(ARPHRD_AX25); 617 arp->ar_pro = htons(AX25_P_IP); 618 break; 619 620 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 621 case ARPHRD_NETROM: 622 arp->ar_hrd = htons(ARPHRD_NETROM); 623 arp->ar_pro = htons(AX25_P_IP); 624 break; 625 #endif 626 #endif 627 628 #ifdef CONFIG_FDDI 629 case ARPHRD_FDDI: 630 arp->ar_hrd = htons(ARPHRD_ETHER); 631 arp->ar_pro = htons(ETH_P_IP); 632 break; 633 #endif 634 #ifdef CONFIG_TR 635 case ARPHRD_IEEE802_TR: 636 arp->ar_hrd = htons(ARPHRD_IEEE802); 637 arp->ar_pro = htons(ETH_P_IP); 638 break; 639 #endif 640 } 641 642 arp->ar_hln = dev->addr_len; 643 arp->ar_pln = 4; 644 arp->ar_op = htons(type); 645 646 arp_ptr=(unsigned char *)(arp+1); 647 648 memcpy(arp_ptr, src_hw, dev->addr_len); 649 arp_ptr+=dev->addr_len; 650 memcpy(arp_ptr, &src_ip,4); 651 arp_ptr+=4; 652 if (target_hw != NULL) 653 memcpy(arp_ptr, target_hw, dev->addr_len); 654 else 655 memset(arp_ptr, 0, dev->addr_len); 656 arp_ptr+=dev->addr_len; 657 memcpy(arp_ptr, &dest_ip, 4); 658 659 return skb; 660 661 out: 662 kfree_skb(skb); 663 return NULL; 664 } 665 666 /* 667 * Send an arp packet. 668 */ 669 void arp_xmit(struct sk_buff *skb) 670 { 671 /* Send it off, maybe filter it using firewalling first. */ 672 NF_HOOK(NF_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 673 } 674 675 /* 676 * Create and send an arp packet. 677 */ 678 void arp_send(int type, int ptype, __be32 dest_ip, 679 struct net_device *dev, __be32 src_ip, 680 unsigned char *dest_hw, unsigned char *src_hw, 681 unsigned char *target_hw) 682 { 683 struct sk_buff *skb; 684 685 /* 686 * No arp on this interface. 687 */ 688 689 if (dev->flags&IFF_NOARP) 690 return; 691 692 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 693 dest_hw, src_hw, target_hw); 694 if (skb == NULL) { 695 return; 696 } 697 698 arp_xmit(skb); 699 } 700 701 /* 702 * Process an arp request. 703 */ 704 705 static int arp_process(struct sk_buff *skb) 706 { 707 struct net_device *dev = skb->dev; 708 struct in_device *in_dev = in_dev_get(dev); 709 struct arphdr *arp; 710 unsigned char *arp_ptr; 711 struct rtable *rt; 712 unsigned char *sha, *tha; 713 __be32 sip, tip; 714 u16 dev_type = dev->type; 715 int addr_type; 716 struct neighbour *n; 717 718 /* arp_rcv below verifies the ARP header and verifies the device 719 * is ARP'able. 720 */ 721 722 if (in_dev == NULL) 723 goto out; 724 725 arp = arp_hdr(skb); 726 727 switch (dev_type) { 728 default: 729 if (arp->ar_pro != htons(ETH_P_IP) || 730 htons(dev_type) != arp->ar_hrd) 731 goto out; 732 break; 733 #ifdef CONFIG_NET_ETHERNET 734 case ARPHRD_ETHER: 735 #endif 736 #ifdef CONFIG_TR 737 case ARPHRD_IEEE802_TR: 738 #endif 739 #ifdef CONFIG_FDDI 740 case ARPHRD_FDDI: 741 #endif 742 #ifdef CONFIG_NET_FC 743 case ARPHRD_IEEE802: 744 #endif 745 #if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_TR) || \ 746 defined(CONFIG_FDDI) || defined(CONFIG_NET_FC) 747 /* 748 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 749 * devices, according to RFC 2625) devices will accept ARP 750 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 751 * This is the case also of FDDI, where the RFC 1390 says that 752 * FDDI devices should accept ARP hardware of (1) Ethernet, 753 * however, to be more robust, we'll accept both 1 (Ethernet) 754 * or 6 (IEEE 802.2) 755 */ 756 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 757 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 758 arp->ar_pro != htons(ETH_P_IP)) 759 goto out; 760 break; 761 #endif 762 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 763 case ARPHRD_AX25: 764 if (arp->ar_pro != htons(AX25_P_IP) || 765 arp->ar_hrd != htons(ARPHRD_AX25)) 766 goto out; 767 break; 768 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 769 case ARPHRD_NETROM: 770 if (arp->ar_pro != htons(AX25_P_IP) || 771 arp->ar_hrd != htons(ARPHRD_NETROM)) 772 goto out; 773 break; 774 #endif 775 #endif 776 } 777 778 /* Understand only these message types */ 779 780 if (arp->ar_op != htons(ARPOP_REPLY) && 781 arp->ar_op != htons(ARPOP_REQUEST)) 782 goto out; 783 784 /* 785 * Extract fields 786 */ 787 arp_ptr= (unsigned char *)(arp+1); 788 sha = arp_ptr; 789 arp_ptr += dev->addr_len; 790 memcpy(&sip, arp_ptr, 4); 791 arp_ptr += 4; 792 tha = arp_ptr; 793 arp_ptr += dev->addr_len; 794 memcpy(&tip, arp_ptr, 4); 795 /* 796 * Check for bad requests for 127.x.x.x and requests for multicast 797 * addresses. If this is one such, delete it. 798 */ 799 if (LOOPBACK(tip) || MULTICAST(tip)) 800 goto out; 801 802 /* 803 * Special case: We must set Frame Relay source Q.922 address 804 */ 805 if (dev_type == ARPHRD_DLCI) 806 sha = dev->broadcast; 807 808 /* 809 * Process entry. The idea here is we want to send a reply if it is a 810 * request for us or if it is a request for someone else that we hold 811 * a proxy for. We want to add an entry to our cache if it is a reply 812 * to us or if it is a request for our address. 813 * (The assumption for this last is that if someone is requesting our 814 * address, they are probably intending to talk to us, so it saves time 815 * if we cache their address. Their address is also probably not in 816 * our cache, since ours is not in their cache.) 817 * 818 * Putting this another way, we only care about replies if they are to 819 * us, in which case we add them to the cache. For requests, we care 820 * about those for us and those for our proxies. We reply to both, 821 * and in the case of requests for us we add the requester to the arp 822 * cache. 823 */ 824 825 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 826 if (sip == 0) { 827 if (arp->ar_op == htons(ARPOP_REQUEST) && 828 inet_addr_type(tip) == RTN_LOCAL && 829 !arp_ignore(in_dev,dev,sip,tip)) 830 arp_send(ARPOP_REPLY,ETH_P_ARP,tip,dev,tip,sha,dev->dev_addr,dev->dev_addr); 831 goto out; 832 } 833 834 if (arp->ar_op == htons(ARPOP_REQUEST) && 835 ip_route_input(skb, tip, sip, 0, dev) == 0) { 836 837 rt = (struct rtable*)skb->dst; 838 addr_type = rt->rt_type; 839 840 if (addr_type == RTN_LOCAL) { 841 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 842 if (n) { 843 int dont_send = 0; 844 845 if (!dont_send) 846 dont_send |= arp_ignore(in_dev,dev,sip,tip); 847 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 848 dont_send |= arp_filter(sip,tip,dev); 849 if (!dont_send) 850 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 851 852 neigh_release(n); 853 } 854 goto out; 855 } else if (IN_DEV_FORWARD(in_dev)) { 856 if ((rt->rt_flags&RTCF_DNAT) || 857 (addr_type == RTN_UNICAST && rt->u.dst.dev != dev && 858 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &tip, dev, 0)))) { 859 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 860 if (n) 861 neigh_release(n); 862 863 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 864 skb->pkt_type == PACKET_HOST || 865 in_dev->arp_parms->proxy_delay == 0) { 866 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); 867 } else { 868 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb); 869 in_dev_put(in_dev); 870 return 0; 871 } 872 goto out; 873 } 874 } 875 } 876 877 /* Update our ARP tables */ 878 879 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 880 881 if (IPV4_DEVCONF_ALL(ARP_ACCEPT)) { 882 /* Unsolicited ARP is not accepted by default. 883 It is possible, that this option should be enabled for some 884 devices (strip is candidate) 885 */ 886 if (n == NULL && 887 arp->ar_op == htons(ARPOP_REPLY) && 888 inet_addr_type(sip) == RTN_UNICAST) 889 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 890 } 891 892 if (n) { 893 int state = NUD_REACHABLE; 894 int override; 895 896 /* If several different ARP replies follows back-to-back, 897 use the FIRST one. It is possible, if several proxy 898 agents are active. Taking the first reply prevents 899 arp trashing and chooses the fastest router. 900 */ 901 override = time_after(jiffies, n->updated + n->parms->locktime); 902 903 /* Broadcast replies and request packets 904 do not assert neighbour reachability. 905 */ 906 if (arp->ar_op != htons(ARPOP_REPLY) || 907 skb->pkt_type != PACKET_HOST) 908 state = NUD_STALE; 909 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0); 910 neigh_release(n); 911 } 912 913 out: 914 if (in_dev) 915 in_dev_put(in_dev); 916 kfree_skb(skb); 917 return 0; 918 } 919 920 static void parp_redo(struct sk_buff *skb) 921 { 922 arp_process(skb); 923 } 924 925 926 /* 927 * Receive an arp request from the device layer. 928 */ 929 930 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 931 struct packet_type *pt, struct net_device *orig_dev) 932 { 933 struct arphdr *arp; 934 935 if (dev->nd_net != &init_net) 936 goto freeskb; 937 938 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 939 if (!pskb_may_pull(skb, (sizeof(struct arphdr) + 940 (2 * dev->addr_len) + 941 (2 * sizeof(u32))))) 942 goto freeskb; 943 944 arp = arp_hdr(skb); 945 if (arp->ar_hln != dev->addr_len || 946 dev->flags & IFF_NOARP || 947 skb->pkt_type == PACKET_OTHERHOST || 948 skb->pkt_type == PACKET_LOOPBACK || 949 arp->ar_pln != 4) 950 goto freeskb; 951 952 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 953 goto out_of_mem; 954 955 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 956 957 return NF_HOOK(NF_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 958 959 freeskb: 960 kfree_skb(skb); 961 out_of_mem: 962 return 0; 963 } 964 965 /* 966 * User level interface (ioctl) 967 */ 968 969 /* 970 * Set (create) an ARP cache entry. 971 */ 972 973 static int arp_req_set(struct arpreq *r, struct net_device * dev) 974 { 975 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 976 struct neighbour *neigh; 977 int err; 978 979 if (r->arp_flags&ATF_PUBL) { 980 __be32 mask = ((struct sockaddr_in *) &r->arp_netmask)->sin_addr.s_addr; 981 if (mask && mask != htonl(0xFFFFFFFF)) 982 return -EINVAL; 983 if (!dev && (r->arp_flags & ATF_COM)) { 984 dev = dev_getbyhwaddr(r->arp_ha.sa_family, r->arp_ha.sa_data); 985 if (!dev) 986 return -ENODEV; 987 } 988 if (mask) { 989 if (pneigh_lookup(&arp_tbl, &ip, dev, 1) == NULL) 990 return -ENOBUFS; 991 return 0; 992 } 993 if (dev == NULL) { 994 IPV4_DEVCONF_ALL(PROXY_ARP) = 1; 995 return 0; 996 } 997 if (__in_dev_get_rtnl(dev)) { 998 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, 1); 999 return 0; 1000 } 1001 return -ENXIO; 1002 } 1003 1004 if (r->arp_flags & ATF_PERM) 1005 r->arp_flags |= ATF_COM; 1006 if (dev == NULL) { 1007 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1008 .tos = RTO_ONLINK } } }; 1009 struct rtable * rt; 1010 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1011 return err; 1012 dev = rt->u.dst.dev; 1013 ip_rt_put(rt); 1014 if (!dev) 1015 return -EINVAL; 1016 } 1017 switch (dev->type) { 1018 #ifdef CONFIG_FDDI 1019 case ARPHRD_FDDI: 1020 /* 1021 * According to RFC 1390, FDDI devices should accept ARP 1022 * hardware types of 1 (Ethernet). However, to be more 1023 * robust, we'll accept hardware types of either 1 (Ethernet) 1024 * or 6 (IEEE 802.2). 1025 */ 1026 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1027 r->arp_ha.sa_family != ARPHRD_ETHER && 1028 r->arp_ha.sa_family != ARPHRD_IEEE802) 1029 return -EINVAL; 1030 break; 1031 #endif 1032 default: 1033 if (r->arp_ha.sa_family != dev->type) 1034 return -EINVAL; 1035 break; 1036 } 1037 1038 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1039 err = PTR_ERR(neigh); 1040 if (!IS_ERR(neigh)) { 1041 unsigned state = NUD_STALE; 1042 if (r->arp_flags & ATF_PERM) 1043 state = NUD_PERMANENT; 1044 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ? 1045 r->arp_ha.sa_data : NULL, state, 1046 NEIGH_UPDATE_F_OVERRIDE| 1047 NEIGH_UPDATE_F_ADMIN); 1048 neigh_release(neigh); 1049 } 1050 return err; 1051 } 1052 1053 static unsigned arp_state_to_flags(struct neighbour *neigh) 1054 { 1055 unsigned flags = 0; 1056 if (neigh->nud_state&NUD_PERMANENT) 1057 flags = ATF_PERM|ATF_COM; 1058 else if (neigh->nud_state&NUD_VALID) 1059 flags = ATF_COM; 1060 return flags; 1061 } 1062 1063 /* 1064 * Get an ARP cache entry. 1065 */ 1066 1067 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1068 { 1069 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1070 struct neighbour *neigh; 1071 int err = -ENXIO; 1072 1073 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1074 if (neigh) { 1075 read_lock_bh(&neigh->lock); 1076 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1077 r->arp_flags = arp_state_to_flags(neigh); 1078 read_unlock_bh(&neigh->lock); 1079 r->arp_ha.sa_family = dev->type; 1080 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1081 neigh_release(neigh); 1082 err = 0; 1083 } 1084 return err; 1085 } 1086 1087 static int arp_req_delete(struct arpreq *r, struct net_device * dev) 1088 { 1089 int err; 1090 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1091 struct neighbour *neigh; 1092 1093 if (r->arp_flags & ATF_PUBL) { 1094 __be32 mask = 1095 ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1096 if (mask == htonl(0xFFFFFFFF)) 1097 return pneigh_delete(&arp_tbl, &ip, dev); 1098 if (mask == 0) { 1099 if (dev == NULL) { 1100 IPV4_DEVCONF_ALL(PROXY_ARP) = 0; 1101 return 0; 1102 } 1103 if (__in_dev_get_rtnl(dev)) { 1104 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), 1105 PROXY_ARP, 0); 1106 return 0; 1107 } 1108 return -ENXIO; 1109 } 1110 return -EINVAL; 1111 } 1112 1113 if (dev == NULL) { 1114 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, 1115 .tos = RTO_ONLINK } } }; 1116 struct rtable * rt; 1117 if ((err = ip_route_output_key(&rt, &fl)) != 0) 1118 return err; 1119 dev = rt->u.dst.dev; 1120 ip_rt_put(rt); 1121 if (!dev) 1122 return -EINVAL; 1123 } 1124 err = -ENXIO; 1125 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1126 if (neigh) { 1127 if (neigh->nud_state&~NUD_NOARP) 1128 err = neigh_update(neigh, NULL, NUD_FAILED, 1129 NEIGH_UPDATE_F_OVERRIDE| 1130 NEIGH_UPDATE_F_ADMIN); 1131 neigh_release(neigh); 1132 } 1133 return err; 1134 } 1135 1136 /* 1137 * Handle an ARP layer I/O control request. 1138 */ 1139 1140 int arp_ioctl(unsigned int cmd, void __user *arg) 1141 { 1142 int err; 1143 struct arpreq r; 1144 struct net_device *dev = NULL; 1145 1146 switch (cmd) { 1147 case SIOCDARP: 1148 case SIOCSARP: 1149 if (!capable(CAP_NET_ADMIN)) 1150 return -EPERM; 1151 case SIOCGARP: 1152 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1153 if (err) 1154 return -EFAULT; 1155 break; 1156 default: 1157 return -EINVAL; 1158 } 1159 1160 if (r.arp_pa.sa_family != AF_INET) 1161 return -EPFNOSUPPORT; 1162 1163 if (!(r.arp_flags & ATF_PUBL) && 1164 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB))) 1165 return -EINVAL; 1166 if (!(r.arp_flags & ATF_NETMASK)) 1167 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1168 htonl(0xFFFFFFFFUL); 1169 rtnl_lock(); 1170 if (r.arp_dev[0]) { 1171 err = -ENODEV; 1172 if ((dev = __dev_get_by_name(r.arp_dev)) == NULL) 1173 goto out; 1174 1175 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1176 if (!r.arp_ha.sa_family) 1177 r.arp_ha.sa_family = dev->type; 1178 err = -EINVAL; 1179 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1180 goto out; 1181 } else if (cmd == SIOCGARP) { 1182 err = -ENODEV; 1183 goto out; 1184 } 1185 1186 switch (cmd) { 1187 case SIOCDARP: 1188 err = arp_req_delete(&r, dev); 1189 break; 1190 case SIOCSARP: 1191 err = arp_req_set(&r, dev); 1192 break; 1193 case SIOCGARP: 1194 err = arp_req_get(&r, dev); 1195 if (!err && copy_to_user(arg, &r, sizeof(r))) 1196 err = -EFAULT; 1197 break; 1198 } 1199 out: 1200 rtnl_unlock(); 1201 return err; 1202 } 1203 1204 static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1205 { 1206 struct net_device *dev = ptr; 1207 1208 switch (event) { 1209 case NETDEV_CHANGEADDR: 1210 neigh_changeaddr(&arp_tbl, dev); 1211 rt_cache_flush(0); 1212 break; 1213 default: 1214 break; 1215 } 1216 1217 return NOTIFY_DONE; 1218 } 1219 1220 static struct notifier_block arp_netdev_notifier = { 1221 .notifier_call = arp_netdev_event, 1222 }; 1223 1224 /* Note, that it is not on notifier chain. 1225 It is necessary, that this routine was called after route cache will be 1226 flushed. 1227 */ 1228 void arp_ifdown(struct net_device *dev) 1229 { 1230 neigh_ifdown(&arp_tbl, dev); 1231 } 1232 1233 1234 /* 1235 * Called once on startup. 1236 */ 1237 1238 static struct packet_type arp_packet_type = { 1239 .type = __constant_htons(ETH_P_ARP), 1240 .func = arp_rcv, 1241 }; 1242 1243 static int arp_proc_init(void); 1244 1245 void __init arp_init(void) 1246 { 1247 neigh_table_init(&arp_tbl); 1248 1249 dev_add_pack(&arp_packet_type); 1250 arp_proc_init(); 1251 #ifdef CONFIG_SYSCTL 1252 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4, 1253 NET_IPV4_NEIGH, "ipv4", NULL, NULL); 1254 #endif 1255 register_netdevice_notifier(&arp_netdev_notifier); 1256 } 1257 1258 #ifdef CONFIG_PROC_FS 1259 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1260 1261 /* ------------------------------------------------------------------------ */ 1262 /* 1263 * ax25 -> ASCII conversion 1264 */ 1265 static char *ax2asc2(ax25_address *a, char *buf) 1266 { 1267 char c, *s; 1268 int n; 1269 1270 for (n = 0, s = buf; n < 6; n++) { 1271 c = (a->ax25_call[n] >> 1) & 0x7F; 1272 1273 if (c != ' ') *s++ = c; 1274 } 1275 1276 *s++ = '-'; 1277 1278 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { 1279 *s++ = '1'; 1280 n -= 10; 1281 } 1282 1283 *s++ = n + '0'; 1284 *s++ = '\0'; 1285 1286 if (*buf == '\0' || *buf == '-') 1287 return "*"; 1288 1289 return buf; 1290 1291 } 1292 #endif /* CONFIG_AX25 */ 1293 1294 #define HBUFFERLEN 30 1295 1296 static void arp_format_neigh_entry(struct seq_file *seq, 1297 struct neighbour *n) 1298 { 1299 char hbuffer[HBUFFERLEN]; 1300 const char hexbuf[] = "0123456789ABCDEF"; 1301 int k, j; 1302 char tbuf[16]; 1303 struct net_device *dev = n->dev; 1304 int hatype = dev->type; 1305 1306 read_lock(&n->lock); 1307 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1308 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1309 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1310 ax2asc2((ax25_address *)n->ha, hbuffer); 1311 else { 1312 #endif 1313 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1314 hbuffer[k++] = hexbuf[(n->ha[j] >> 4) & 15]; 1315 hbuffer[k++] = hexbuf[n->ha[j] & 15]; 1316 hbuffer[k++] = ':'; 1317 } 1318 hbuffer[--k] = 0; 1319 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1320 } 1321 #endif 1322 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->primary_key)); 1323 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1324 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1325 read_unlock(&n->lock); 1326 } 1327 1328 static void arp_format_pneigh_entry(struct seq_file *seq, 1329 struct pneigh_entry *n) 1330 { 1331 struct net_device *dev = n->dev; 1332 int hatype = dev ? dev->type : 0; 1333 char tbuf[16]; 1334 1335 sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(*(u32*)n->key)); 1336 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1337 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1338 dev ? dev->name : "*"); 1339 } 1340 1341 static int arp_seq_show(struct seq_file *seq, void *v) 1342 { 1343 if (v == SEQ_START_TOKEN) { 1344 seq_puts(seq, "IP address HW type Flags " 1345 "HW address Mask Device\n"); 1346 } else { 1347 struct neigh_seq_state *state = seq->private; 1348 1349 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1350 arp_format_pneigh_entry(seq, v); 1351 else 1352 arp_format_neigh_entry(seq, v); 1353 } 1354 1355 return 0; 1356 } 1357 1358 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1359 { 1360 /* Don't want to confuse "arp -a" w/ magic entries, 1361 * so we tell the generic iterator to skip NUD_NOARP. 1362 */ 1363 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1364 } 1365 1366 /* ------------------------------------------------------------------------ */ 1367 1368 static const struct seq_operations arp_seq_ops = { 1369 .start = arp_seq_start, 1370 .next = neigh_seq_next, 1371 .stop = neigh_seq_stop, 1372 .show = arp_seq_show, 1373 }; 1374 1375 static int arp_seq_open(struct inode *inode, struct file *file) 1376 { 1377 struct seq_file *seq; 1378 int rc = -ENOMEM; 1379 struct neigh_seq_state *s = kzalloc(sizeof(*s), GFP_KERNEL); 1380 1381 if (!s) 1382 goto out; 1383 1384 rc = seq_open(file, &arp_seq_ops); 1385 if (rc) 1386 goto out_kfree; 1387 1388 seq = file->private_data; 1389 seq->private = s; 1390 out: 1391 return rc; 1392 out_kfree: 1393 kfree(s); 1394 goto out; 1395 } 1396 1397 static const struct file_operations arp_seq_fops = { 1398 .owner = THIS_MODULE, 1399 .open = arp_seq_open, 1400 .read = seq_read, 1401 .llseek = seq_lseek, 1402 .release = seq_release_private, 1403 }; 1404 1405 static int __init arp_proc_init(void) 1406 { 1407 if (!proc_net_fops_create(&init_net, "arp", S_IRUGO, &arp_seq_fops)) 1408 return -ENOMEM; 1409 return 0; 1410 } 1411 1412 #else /* CONFIG_PROC_FS */ 1413 1414 static int __init arp_proc_init(void) 1415 { 1416 return 0; 1417 } 1418 1419 #endif /* CONFIG_PROC_FS */ 1420 1421 EXPORT_SYMBOL(arp_broken_ops); 1422 EXPORT_SYMBOL(arp_find); 1423 EXPORT_SYMBOL(arp_create); 1424 EXPORT_SYMBOL(arp_xmit); 1425 EXPORT_SYMBOL(arp_send); 1426 EXPORT_SYMBOL(arp_tbl); 1427 1428 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 1429 EXPORT_SYMBOL(clip_tbl_hook); 1430 #endif 1431