1 /* linux/net/ipv4/arp.c 2 * 3 * Copyright (C) 1994 by Florian La Roche 4 * 5 * This module implements the Address Resolution Protocol ARP (RFC 826), 6 * which is used to convert IP addresses (or in the future maybe other 7 * high-level addresses) into a low-level hardware address (like an Ethernet 8 * address). 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 * 15 * Fixes: 16 * Alan Cox : Removed the Ethernet assumptions in 17 * Florian's code 18 * Alan Cox : Fixed some small errors in the ARP 19 * logic 20 * Alan Cox : Allow >4K in /proc 21 * Alan Cox : Make ARP add its own protocol entry 22 * Ross Martin : Rewrote arp_rcv() and arp_get_info() 23 * Stephen Henson : Add AX25 support to arp_get_info() 24 * Alan Cox : Drop data when a device is downed. 25 * Alan Cox : Use init_timer(). 26 * Alan Cox : Double lock fixes. 27 * Martin Seine : Move the arphdr structure 28 * to if_arp.h for compatibility. 29 * with BSD based programs. 30 * Andrew Tridgell : Added ARP netmask code and 31 * re-arranged proxy handling. 32 * Alan Cox : Changed to use notifiers. 33 * Niibe Yutaka : Reply for this device or proxies only. 34 * Alan Cox : Don't proxy across hardware types! 35 * Jonathan Naylor : Added support for NET/ROM. 36 * Mike Shaver : RFC1122 checks. 37 * Jonathan Naylor : Only lookup the hardware address for 38 * the correct hardware type. 39 * Germano Caronni : Assorted subtle races. 40 * Craig Schlenter : Don't modify permanent entry 41 * during arp_rcv. 42 * Russ Nelson : Tidied up a few bits. 43 * Alexey Kuznetsov: Major changes to caching and behaviour, 44 * eg intelligent arp probing and 45 * generation 46 * of host down events. 47 * Alan Cox : Missing unlock in device events. 48 * Eckes : ARP ioctl control errors. 49 * Alexey Kuznetsov: Arp free fix. 50 * Manuel Rodriguez: Gratuitous ARP. 51 * Jonathan Layes : Added arpd support through kerneld 52 * message queue (960314) 53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support 54 * Mike McLagan : Routing by source 55 * Stuart Cheshire : Metricom and grat arp fixes 56 * *** FOR 2.1 clean this up *** 57 * Lawrence V. Stefani: (08/12/96) Added FDDI support. 58 * Alan Cox : Took the AP1000 nasty FDDI hack and 59 * folded into the mainstream FDDI code. 60 * Ack spit, Linus how did you allow that 61 * one in... 62 * Jes Sorensen : Make FDDI work again in 2.1.x and 63 * clean up the APFDDI & gen. FDDI bits. 64 * Alexey Kuznetsov: new arp state machine; 65 * now it is in net/core/neighbour.c. 66 * Krzysztof Halasa: Added Frame Relay ARP support. 67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file 68 * Shmulik Hen: Split arp_send to arp_create and 69 * arp_xmit so intermediate drivers like 70 * bonding can change the skb before 71 * sending (e.g. insert 8021q tag). 72 * Harald Welte : convert to make use of jenkins hash 73 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support. 74 */ 75 76 #include <linux/module.h> 77 #include <linux/types.h> 78 #include <linux/string.h> 79 #include <linux/kernel.h> 80 #include <linux/capability.h> 81 #include <linux/socket.h> 82 #include <linux/sockios.h> 83 #include <linux/errno.h> 84 #include <linux/in.h> 85 #include <linux/mm.h> 86 #include <linux/inet.h> 87 #include <linux/inetdevice.h> 88 #include <linux/netdevice.h> 89 #include <linux/etherdevice.h> 90 #include <linux/fddidevice.h> 91 #include <linux/if_arp.h> 92 #include <linux/trdevice.h> 93 #include <linux/skbuff.h> 94 #include <linux/proc_fs.h> 95 #include <linux/seq_file.h> 96 #include <linux/stat.h> 97 #include <linux/init.h> 98 #include <linux/net.h> 99 #include <linux/rcupdate.h> 100 #include <linux/slab.h> 101 #ifdef CONFIG_SYSCTL 102 #include <linux/sysctl.h> 103 #endif 104 105 #include <net/net_namespace.h> 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 #include <net/ax25.h> 114 #include <net/netrom.h> 115 #if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE) 116 #include <net/atmclip.h> 117 struct neigh_table *clip_tbl_hook; 118 EXPORT_SYMBOL(clip_tbl_hook); 119 #endif 120 121 #include <asm/system.h> 122 #include <linux/uaccess.h> 123 124 #include <linux/netfilter_arp.h> 125 126 /* 127 * Interface to generic neighbour cache. 128 */ 129 static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 rnd); 130 static int arp_constructor(struct neighbour *neigh); 131 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 132 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 133 static void parp_redo(struct sk_buff *skb); 134 135 static const struct neigh_ops arp_generic_ops = { 136 .family = AF_INET, 137 .solicit = arp_solicit, 138 .error_report = arp_error_report, 139 .output = neigh_resolve_output, 140 .connected_output = neigh_connected_output, 141 }; 142 143 static const struct neigh_ops arp_hh_ops = { 144 .family = AF_INET, 145 .solicit = arp_solicit, 146 .error_report = arp_error_report, 147 .output = neigh_resolve_output, 148 .connected_output = neigh_resolve_output, 149 }; 150 151 static const struct neigh_ops arp_direct_ops = { 152 .family = AF_INET, 153 .output = neigh_direct_output, 154 .connected_output = neigh_direct_output, 155 }; 156 157 static const struct neigh_ops arp_broken_ops = { 158 .family = AF_INET, 159 .solicit = arp_solicit, 160 .error_report = arp_error_report, 161 .output = neigh_compat_output, 162 .connected_output = neigh_compat_output, 163 }; 164 165 struct neigh_table arp_tbl = { 166 .family = AF_INET, 167 .entry_size = sizeof(struct neighbour) + 4, 168 .key_len = 4, 169 .hash = arp_hash, 170 .constructor = arp_constructor, 171 .proxy_redo = parp_redo, 172 .id = "arp_cache", 173 .parms = { 174 .tbl = &arp_tbl, 175 .base_reachable_time = 30 * HZ, 176 .retrans_time = 1 * HZ, 177 .gc_staletime = 60 * HZ, 178 .reachable_time = 30 * HZ, 179 .delay_probe_time = 5 * HZ, 180 .queue_len = 3, 181 .ucast_probes = 3, 182 .mcast_probes = 3, 183 .anycast_delay = 1 * HZ, 184 .proxy_delay = (8 * HZ) / 10, 185 .proxy_qlen = 64, 186 .locktime = 1 * HZ, 187 }, 188 .gc_interval = 30 * HZ, 189 .gc_thresh1 = 128, 190 .gc_thresh2 = 512, 191 .gc_thresh3 = 1024, 192 }; 193 EXPORT_SYMBOL(arp_tbl); 194 195 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 196 { 197 switch (dev->type) { 198 case ARPHRD_ETHER: 199 case ARPHRD_FDDI: 200 case ARPHRD_IEEE802: 201 ip_eth_mc_map(addr, haddr); 202 return 0; 203 case ARPHRD_IEEE802_TR: 204 ip_tr_mc_map(addr, haddr); 205 return 0; 206 case ARPHRD_INFINIBAND: 207 ip_ib_mc_map(addr, dev->broadcast, haddr); 208 return 0; 209 case ARPHRD_IPGRE: 210 ip_ipgre_mc_map(addr, dev->broadcast, haddr); 211 return 0; 212 default: 213 if (dir) { 214 memcpy(haddr, dev->broadcast, dev->addr_len); 215 return 0; 216 } 217 } 218 return -EINVAL; 219 } 220 221 222 static u32 arp_hash(const void *pkey, 223 const struct net_device *dev, 224 __u32 hash_rnd) 225 { 226 return arp_hashfn(*(u32 *)pkey, dev, hash_rnd); 227 } 228 229 static int arp_constructor(struct neighbour *neigh) 230 { 231 __be32 addr = *(__be32 *)neigh->primary_key; 232 struct net_device *dev = neigh->dev; 233 struct in_device *in_dev; 234 struct neigh_parms *parms; 235 236 rcu_read_lock(); 237 in_dev = __in_dev_get_rcu(dev); 238 if (in_dev == NULL) { 239 rcu_read_unlock(); 240 return -EINVAL; 241 } 242 243 neigh->type = inet_addr_type(dev_net(dev), addr); 244 245 parms = in_dev->arp_parms; 246 __neigh_parms_put(neigh->parms); 247 neigh->parms = neigh_parms_clone(parms); 248 rcu_read_unlock(); 249 250 if (!dev->header_ops) { 251 neigh->nud_state = NUD_NOARP; 252 neigh->ops = &arp_direct_ops; 253 neigh->output = neigh_direct_output; 254 } else { 255 /* Good devices (checked by reading texts, but only Ethernet is 256 tested) 257 258 ARPHRD_ETHER: (ethernet, apfddi) 259 ARPHRD_FDDI: (fddi) 260 ARPHRD_IEEE802: (tr) 261 ARPHRD_METRICOM: (strip) 262 ARPHRD_ARCNET: 263 etc. etc. etc. 264 265 ARPHRD_IPDDP will also work, if author repairs it. 266 I did not it, because this driver does not work even 267 in old paradigm. 268 */ 269 270 #if 1 271 /* So... these "amateur" devices are hopeless. 272 The only thing, that I can say now: 273 It is very sad that we need to keep ugly obsolete 274 code to make them happy. 275 276 They should be moved to more reasonable state, now 277 they use rebuild_header INSTEAD OF hard_start_xmit!!! 278 Besides that, they are sort of out of date 279 (a lot of redundant clones/copies, useless in 2.1), 280 I wonder why people believe that they work. 281 */ 282 switch (dev->type) { 283 default: 284 break; 285 case ARPHRD_ROSE: 286 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 287 case ARPHRD_AX25: 288 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 289 case ARPHRD_NETROM: 290 #endif 291 neigh->ops = &arp_broken_ops; 292 neigh->output = neigh->ops->output; 293 return 0; 294 #else 295 break; 296 #endif 297 } 298 #endif 299 if (neigh->type == RTN_MULTICAST) { 300 neigh->nud_state = NUD_NOARP; 301 arp_mc_map(addr, neigh->ha, dev, 1); 302 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 303 neigh->nud_state = NUD_NOARP; 304 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 305 } else if (neigh->type == RTN_BROADCAST || 306 (dev->flags & IFF_POINTOPOINT)) { 307 neigh->nud_state = NUD_NOARP; 308 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 309 } 310 311 if (dev->header_ops->cache) 312 neigh->ops = &arp_hh_ops; 313 else 314 neigh->ops = &arp_generic_ops; 315 316 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; 338 339 rcu_read_lock(); 340 in_dev = __in_dev_get_rcu(dev); 341 if (!in_dev) { 342 rcu_read_unlock(); 343 return; 344 } 345 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 346 default: 347 case 0: /* By default announce any local IP */ 348 if (skb && inet_addr_type(dev_net(dev), 349 ip_hdr(skb)->saddr) == RTN_LOCAL) 350 saddr = ip_hdr(skb)->saddr; 351 break; 352 case 1: /* Restrict announcements of saddr in same subnet */ 353 if (!skb) 354 break; 355 saddr = ip_hdr(skb)->saddr; 356 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { 357 /* saddr should be known to target */ 358 if (inet_addr_onlink(in_dev, target, saddr)) 359 break; 360 } 361 saddr = 0; 362 break; 363 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 364 break; 365 } 366 rcu_read_unlock(); 367 368 if (!saddr) 369 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 370 371 probes -= neigh->parms->ucast_probes; 372 if (probes < 0) { 373 if (!(neigh->nud_state & NUD_VALID)) 374 printk(KERN_DEBUG 375 "trying to ucast probe in NUD_INVALID\n"); 376 dst_ha = neigh->ha; 377 read_lock_bh(&neigh->lock); 378 } else { 379 probes -= neigh->parms->app_probes; 380 if (probes < 0) { 381 #ifdef CONFIG_ARPD 382 neigh_app_ns(neigh); 383 #endif 384 return; 385 } 386 } 387 388 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 389 dst_ha, dev->dev_addr, NULL); 390 if (dst_ha) 391 read_unlock_bh(&neigh->lock); 392 } 393 394 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 395 { 396 int scope; 397 398 switch (IN_DEV_ARP_IGNORE(in_dev)) { 399 case 0: /* Reply, the tip is already validated */ 400 return 0; 401 case 1: /* Reply only if tip is configured on the incoming interface */ 402 sip = 0; 403 scope = RT_SCOPE_HOST; 404 break; 405 case 2: /* 406 * Reply only if tip is configured on the incoming interface 407 * and is in same subnet as sip 408 */ 409 scope = RT_SCOPE_HOST; 410 break; 411 case 3: /* Do not reply for scope host addresses */ 412 sip = 0; 413 scope = RT_SCOPE_LINK; 414 break; 415 case 4: /* Reserved */ 416 case 5: 417 case 6: 418 case 7: 419 return 0; 420 case 8: /* Do not reply */ 421 return 1; 422 default: 423 return 0; 424 } 425 return !inet_confirm_addr(in_dev, sip, tip, scope); 426 } 427 428 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 429 { 430 struct rtable *rt; 431 int flag = 0; 432 /*unsigned long now; */ 433 struct net *net = dev_net(dev); 434 435 rt = ip_route_output(net, sip, tip, 0, 0); 436 if (IS_ERR(rt)) 437 return 1; 438 if (rt->dst.dev != dev) { 439 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); 440 flag = 1; 441 } 442 ip_rt_put(rt); 443 return flag; 444 } 445 446 /* OBSOLETE FUNCTIONS */ 447 448 /* 449 * Find an arp mapping in the cache. If not found, post a request. 450 * 451 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 452 * even if it exists. It is supposed that skb->dev was mangled 453 * by a virtual device (eql, shaper). Nobody but broken devices 454 * is allowed to use this function, it is scheduled to be removed. --ANK 455 */ 456 457 static int arp_set_predefined(int addr_hint, unsigned char *haddr, 458 __be32 paddr, struct net_device *dev) 459 { 460 switch (addr_hint) { 461 case RTN_LOCAL: 462 printk(KERN_DEBUG "ARP: arp called for own IP address\n"); 463 memcpy(haddr, dev->dev_addr, dev->addr_len); 464 return 1; 465 case RTN_MULTICAST: 466 arp_mc_map(paddr, haddr, dev, 1); 467 return 1; 468 case RTN_BROADCAST: 469 memcpy(haddr, dev->broadcast, dev->addr_len); 470 return 1; 471 } 472 return 0; 473 } 474 475 476 int arp_find(unsigned char *haddr, struct sk_buff *skb) 477 { 478 struct net_device *dev = skb->dev; 479 __be32 paddr; 480 struct neighbour *n; 481 482 if (!skb_dst(skb)) { 483 printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); 484 kfree_skb(skb); 485 return 1; 486 } 487 488 paddr = skb_rtable(skb)->rt_gateway; 489 490 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, 491 paddr, dev)) 492 return 0; 493 494 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 495 496 if (n) { 497 n->used = jiffies; 498 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) { 499 neigh_ha_snapshot(haddr, n, dev); 500 neigh_release(n); 501 return 0; 502 } 503 neigh_release(n); 504 } else 505 kfree_skb(skb); 506 return 1; 507 } 508 EXPORT_SYMBOL(arp_find); 509 510 /* END OF OBSOLETE FUNCTIONS */ 511 512 /* 513 * Check if we can use proxy ARP for this path 514 */ 515 static inline int arp_fwd_proxy(struct in_device *in_dev, 516 struct net_device *dev, struct rtable *rt) 517 { 518 struct in_device *out_dev; 519 int imi, omi = -1; 520 521 if (rt->dst.dev == dev) 522 return 0; 523 524 if (!IN_DEV_PROXY_ARP(in_dev)) 525 return 0; 526 imi = IN_DEV_MEDIUM_ID(in_dev); 527 if (imi == 0) 528 return 1; 529 if (imi == -1) 530 return 0; 531 532 /* place to check for proxy_arp for routes */ 533 534 out_dev = __in_dev_get_rcu(rt->dst.dev); 535 if (out_dev) 536 omi = IN_DEV_MEDIUM_ID(out_dev); 537 538 return omi != imi && omi != -1; 539 } 540 541 /* 542 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 543 * 544 * RFC3069 supports proxy arp replies back to the same interface. This 545 * is done to support (ethernet) switch features, like RFC 3069, where 546 * the individual ports are not allowed to communicate with each 547 * other, BUT they are allowed to talk to the upstream router. As 548 * described in RFC 3069, it is possible to allow these hosts to 549 * communicate through the upstream router, by proxy_arp'ing. 550 * 551 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 552 * 553 * This technology is known by different names: 554 * In RFC 3069 it is called VLAN Aggregation. 555 * Cisco and Allied Telesyn call it Private VLAN. 556 * Hewlett-Packard call it Source-Port filtering or port-isolation. 557 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 558 * 559 */ 560 static inline int arp_fwd_pvlan(struct in_device *in_dev, 561 struct net_device *dev, struct rtable *rt, 562 __be32 sip, __be32 tip) 563 { 564 /* Private VLAN is only concerned about the same ethernet segment */ 565 if (rt->dst.dev != dev) 566 return 0; 567 568 /* Don't reply on self probes (often done by windowz boxes)*/ 569 if (sip == tip) 570 return 0; 571 572 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 573 return 1; 574 else 575 return 0; 576 } 577 578 /* 579 * Interface to link layer: send routine and receive handler. 580 */ 581 582 /* 583 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 584 * message. 585 */ 586 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 587 struct net_device *dev, __be32 src_ip, 588 const unsigned char *dest_hw, 589 const unsigned char *src_hw, 590 const unsigned char *target_hw) 591 { 592 struct sk_buff *skb; 593 struct arphdr *arp; 594 unsigned char *arp_ptr; 595 596 /* 597 * Allocate a buffer 598 */ 599 600 skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC); 601 if (skb == NULL) 602 return NULL; 603 604 skb_reserve(skb, LL_RESERVED_SPACE(dev)); 605 skb_reset_network_header(skb); 606 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); 607 skb->dev = dev; 608 skb->protocol = htons(ETH_P_ARP); 609 if (src_hw == NULL) 610 src_hw = dev->dev_addr; 611 if (dest_hw == NULL) 612 dest_hw = dev->broadcast; 613 614 /* 615 * Fill the device header for the ARP frame 616 */ 617 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 618 goto out; 619 620 /* 621 * Fill out the arp protocol part. 622 * 623 * The arp hardware type should match the device type, except for FDDI, 624 * which (according to RFC 1390) should always equal 1 (Ethernet). 625 */ 626 /* 627 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 628 * DIX code for the protocol. Make these device structure fields. 629 */ 630 switch (dev->type) { 631 default: 632 arp->ar_hrd = htons(dev->type); 633 arp->ar_pro = htons(ETH_P_IP); 634 break; 635 636 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 637 case ARPHRD_AX25: 638 arp->ar_hrd = htons(ARPHRD_AX25); 639 arp->ar_pro = htons(AX25_P_IP); 640 break; 641 642 #if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE) 643 case ARPHRD_NETROM: 644 arp->ar_hrd = htons(ARPHRD_NETROM); 645 arp->ar_pro = htons(AX25_P_IP); 646 break; 647 #endif 648 #endif 649 650 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE) 651 case ARPHRD_FDDI: 652 arp->ar_hrd = htons(ARPHRD_ETHER); 653 arp->ar_pro = htons(ETH_P_IP); 654 break; 655 #endif 656 #if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE) 657 case ARPHRD_IEEE802_TR: 658 arp->ar_hrd = htons(ARPHRD_IEEE802); 659 arp->ar_pro = htons(ETH_P_IP); 660 break; 661 #endif 662 } 663 664 arp->ar_hln = dev->addr_len; 665 arp->ar_pln = 4; 666 arp->ar_op = htons(type); 667 668 arp_ptr = (unsigned char *)(arp + 1); 669 670 memcpy(arp_ptr, src_hw, dev->addr_len); 671 arp_ptr += dev->addr_len; 672 memcpy(arp_ptr, &src_ip, 4); 673 arp_ptr += 4; 674 if (target_hw != NULL) 675 memcpy(arp_ptr, target_hw, dev->addr_len); 676 else 677 memset(arp_ptr, 0, dev->addr_len); 678 arp_ptr += dev->addr_len; 679 memcpy(arp_ptr, &dest_ip, 4); 680 681 return skb; 682 683 out: 684 kfree_skb(skb); 685 return NULL; 686 } 687 EXPORT_SYMBOL(arp_create); 688 689 /* 690 * Send an arp packet. 691 */ 692 void arp_xmit(struct sk_buff *skb) 693 { 694 /* Send it off, maybe filter it using firewalling first. */ 695 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 696 } 697 EXPORT_SYMBOL(arp_xmit); 698 699 /* 700 * Create and send an arp packet. 701 */ 702 void arp_send(int type, int ptype, __be32 dest_ip, 703 struct net_device *dev, __be32 src_ip, 704 const unsigned char *dest_hw, const unsigned char *src_hw, 705 const unsigned char *target_hw) 706 { 707 struct sk_buff *skb; 708 709 /* 710 * No arp on this interface. 711 */ 712 713 if (dev->flags&IFF_NOARP) 714 return; 715 716 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 717 dest_hw, src_hw, target_hw); 718 if (skb == NULL) 719 return; 720 721 arp_xmit(skb); 722 } 723 EXPORT_SYMBOL(arp_send); 724 725 /* 726 * Process an arp request. 727 */ 728 729 static int arp_process(struct sk_buff *skb) 730 { 731 struct net_device *dev = skb->dev; 732 struct in_device *in_dev = __in_dev_get_rcu(dev); 733 struct arphdr *arp; 734 unsigned char *arp_ptr; 735 struct rtable *rt; 736 unsigned char *sha; 737 __be32 sip, tip; 738 u16 dev_type = dev->type; 739 int addr_type; 740 struct neighbour *n; 741 struct net *net = dev_net(dev); 742 743 /* arp_rcv below verifies the ARP header and verifies the device 744 * is ARP'able. 745 */ 746 747 if (in_dev == NULL) 748 goto out; 749 750 arp = arp_hdr(skb); 751 752 switch (dev_type) { 753 default: 754 if (arp->ar_pro != htons(ETH_P_IP) || 755 htons(dev_type) != arp->ar_hrd) 756 goto out; 757 break; 758 case ARPHRD_ETHER: 759 case ARPHRD_IEEE802_TR: 760 case ARPHRD_FDDI: 761 case ARPHRD_IEEE802: 762 /* 763 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 764 * devices, according to RFC 2625) devices will accept ARP 765 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 766 * This is the case also of FDDI, where the RFC 1390 says that 767 * FDDI devices should accept ARP hardware of (1) Ethernet, 768 * however, to be more robust, we'll accept both 1 (Ethernet) 769 * or 6 (IEEE 802.2) 770 */ 771 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 772 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 773 arp->ar_pro != htons(ETH_P_IP)) 774 goto out; 775 break; 776 case ARPHRD_AX25: 777 if (arp->ar_pro != htons(AX25_P_IP) || 778 arp->ar_hrd != htons(ARPHRD_AX25)) 779 goto out; 780 break; 781 case ARPHRD_NETROM: 782 if (arp->ar_pro != htons(AX25_P_IP) || 783 arp->ar_hrd != htons(ARPHRD_NETROM)) 784 goto out; 785 break; 786 } 787 788 /* Understand only these message types */ 789 790 if (arp->ar_op != htons(ARPOP_REPLY) && 791 arp->ar_op != htons(ARPOP_REQUEST)) 792 goto out; 793 794 /* 795 * Extract fields 796 */ 797 arp_ptr = (unsigned char *)(arp + 1); 798 sha = arp_ptr; 799 arp_ptr += dev->addr_len; 800 memcpy(&sip, arp_ptr, 4); 801 arp_ptr += 4; 802 arp_ptr += dev->addr_len; 803 memcpy(&tip, arp_ptr, 4); 804 /* 805 * Check for bad requests for 127.x.x.x and requests for multicast 806 * addresses. If this is one such, delete it. 807 */ 808 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip)) 809 goto out; 810 811 /* 812 * Special case: We must set Frame Relay source Q.922 address 813 */ 814 if (dev_type == ARPHRD_DLCI) 815 sha = dev->broadcast; 816 817 /* 818 * Process entry. The idea here is we want to send a reply if it is a 819 * request for us or if it is a request for someone else that we hold 820 * a proxy for. We want to add an entry to our cache if it is a reply 821 * to us or if it is a request for our address. 822 * (The assumption for this last is that if someone is requesting our 823 * address, they are probably intending to talk to us, so it saves time 824 * if we cache their address. Their address is also probably not in 825 * our cache, since ours is not in their cache.) 826 * 827 * Putting this another way, we only care about replies if they are to 828 * us, in which case we add them to the cache. For requests, we care 829 * about those for us and those for our proxies. We reply to both, 830 * and in the case of requests for us we add the requester to the arp 831 * cache. 832 */ 833 834 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 835 if (sip == 0) { 836 if (arp->ar_op == htons(ARPOP_REQUEST) && 837 inet_addr_type(net, tip) == RTN_LOCAL && 838 !arp_ignore(in_dev, sip, tip)) 839 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, 840 dev->dev_addr, sha); 841 goto out; 842 } 843 844 if (arp->ar_op == htons(ARPOP_REQUEST) && 845 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 846 847 rt = skb_rtable(skb); 848 addr_type = rt->rt_type; 849 850 if (addr_type == RTN_LOCAL) { 851 int dont_send; 852 853 dont_send = arp_ignore(in_dev, sip, tip); 854 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 855 dont_send = arp_filter(sip, tip, dev); 856 if (!dont_send) { 857 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 858 if (n) { 859 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 860 dev, tip, sha, dev->dev_addr, 861 sha); 862 neigh_release(n); 863 } 864 } 865 goto out; 866 } else if (IN_DEV_FORWARD(in_dev)) { 867 if (addr_type == RTN_UNICAST && 868 (arp_fwd_proxy(in_dev, dev, rt) || 869 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 870 pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) { 871 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 872 if (n) 873 neigh_release(n); 874 875 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 876 skb->pkt_type == PACKET_HOST || 877 in_dev->arp_parms->proxy_delay == 0) { 878 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 879 dev, tip, sha, dev->dev_addr, 880 sha); 881 } else { 882 pneigh_enqueue(&arp_tbl, 883 in_dev->arp_parms, skb); 884 return 0; 885 } 886 goto out; 887 } 888 } 889 } 890 891 /* Update our ARP tables */ 892 893 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 894 895 if (IPV4_DEVCONF_ALL(dev_net(dev), ARP_ACCEPT)) { 896 /* Unsolicited ARP is not accepted by default. 897 It is possible, that this option should be enabled for some 898 devices (strip is candidate) 899 */ 900 if (n == NULL && 901 (arp->ar_op == htons(ARPOP_REPLY) || 902 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) && 903 inet_addr_type(net, sip) == RTN_UNICAST) 904 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 905 } 906 907 if (n) { 908 int state = NUD_REACHABLE; 909 int override; 910 911 /* If several different ARP replies follows back-to-back, 912 use the FIRST one. It is possible, if several proxy 913 agents are active. Taking the first reply prevents 914 arp trashing and chooses the fastest router. 915 */ 916 override = time_after(jiffies, n->updated + n->parms->locktime); 917 918 /* Broadcast replies and request packets 919 do not assert neighbour reachability. 920 */ 921 if (arp->ar_op != htons(ARPOP_REPLY) || 922 skb->pkt_type != PACKET_HOST) 923 state = NUD_STALE; 924 neigh_update(n, sha, state, 925 override ? NEIGH_UPDATE_F_OVERRIDE : 0); 926 neigh_release(n); 927 } 928 929 out: 930 consume_skb(skb); 931 return 0; 932 } 933 934 static void parp_redo(struct sk_buff *skb) 935 { 936 arp_process(skb); 937 } 938 939 940 /* 941 * Receive an arp request from the device layer. 942 */ 943 944 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 945 struct packet_type *pt, struct net_device *orig_dev) 946 { 947 struct arphdr *arp; 948 949 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 950 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 951 goto freeskb; 952 953 arp = arp_hdr(skb); 954 if (arp->ar_hln != dev->addr_len || 955 dev->flags & IFF_NOARP || 956 skb->pkt_type == PACKET_OTHERHOST || 957 skb->pkt_type == PACKET_LOOPBACK || 958 arp->ar_pln != 4) 959 goto freeskb; 960 961 skb = skb_share_check(skb, GFP_ATOMIC); 962 if (skb == NULL) 963 goto out_of_mem; 964 965 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 966 967 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 968 969 freeskb: 970 kfree_skb(skb); 971 out_of_mem: 972 return 0; 973 } 974 975 /* 976 * User level interface (ioctl) 977 */ 978 979 /* 980 * Set (create) an ARP cache entry. 981 */ 982 983 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 984 { 985 if (dev == NULL) { 986 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 987 return 0; 988 } 989 if (__in_dev_get_rtnl(dev)) { 990 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 991 return 0; 992 } 993 return -ENXIO; 994 } 995 996 static int arp_req_set_public(struct net *net, struct arpreq *r, 997 struct net_device *dev) 998 { 999 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1000 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1001 1002 if (mask && mask != htonl(0xFFFFFFFF)) 1003 return -EINVAL; 1004 if (!dev && (r->arp_flags & ATF_COM)) { 1005 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 1006 r->arp_ha.sa_data); 1007 if (!dev) 1008 return -ENODEV; 1009 } 1010 if (mask) { 1011 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL) 1012 return -ENOBUFS; 1013 return 0; 1014 } 1015 1016 return arp_req_set_proxy(net, dev, 1); 1017 } 1018 1019 static int arp_req_set(struct net *net, struct arpreq *r, 1020 struct net_device *dev) 1021 { 1022 __be32 ip; 1023 struct neighbour *neigh; 1024 int err; 1025 1026 if (r->arp_flags & ATF_PUBL) 1027 return arp_req_set_public(net, r, dev); 1028 1029 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1030 if (r->arp_flags & ATF_PERM) 1031 r->arp_flags |= ATF_COM; 1032 if (dev == NULL) { 1033 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1034 1035 if (IS_ERR(rt)) 1036 return PTR_ERR(rt); 1037 dev = rt->dst.dev; 1038 ip_rt_put(rt); 1039 if (!dev) 1040 return -EINVAL; 1041 } 1042 switch (dev->type) { 1043 #if defined(CONFIG_FDDI) || defined(CONFIG_FDDI_MODULE) 1044 case ARPHRD_FDDI: 1045 /* 1046 * According to RFC 1390, FDDI devices should accept ARP 1047 * hardware types of 1 (Ethernet). However, to be more 1048 * robust, we'll accept hardware types of either 1 (Ethernet) 1049 * or 6 (IEEE 802.2). 1050 */ 1051 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1052 r->arp_ha.sa_family != ARPHRD_ETHER && 1053 r->arp_ha.sa_family != ARPHRD_IEEE802) 1054 return -EINVAL; 1055 break; 1056 #endif 1057 default: 1058 if (r->arp_ha.sa_family != dev->type) 1059 return -EINVAL; 1060 break; 1061 } 1062 1063 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1064 err = PTR_ERR(neigh); 1065 if (!IS_ERR(neigh)) { 1066 unsigned state = NUD_STALE; 1067 if (r->arp_flags & ATF_PERM) 1068 state = NUD_PERMANENT; 1069 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1070 r->arp_ha.sa_data : NULL, state, 1071 NEIGH_UPDATE_F_OVERRIDE | 1072 NEIGH_UPDATE_F_ADMIN); 1073 neigh_release(neigh); 1074 } 1075 return err; 1076 } 1077 1078 static unsigned arp_state_to_flags(struct neighbour *neigh) 1079 { 1080 if (neigh->nud_state&NUD_PERMANENT) 1081 return ATF_PERM | ATF_COM; 1082 else if (neigh->nud_state&NUD_VALID) 1083 return ATF_COM; 1084 else 1085 return 0; 1086 } 1087 1088 /* 1089 * Get an ARP cache entry. 1090 */ 1091 1092 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1093 { 1094 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1095 struct neighbour *neigh; 1096 int err = -ENXIO; 1097 1098 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1099 if (neigh) { 1100 read_lock_bh(&neigh->lock); 1101 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1102 r->arp_flags = arp_state_to_flags(neigh); 1103 read_unlock_bh(&neigh->lock); 1104 r->arp_ha.sa_family = dev->type; 1105 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1106 neigh_release(neigh); 1107 err = 0; 1108 } 1109 return err; 1110 } 1111 1112 int arp_invalidate(struct net_device *dev, __be32 ip) 1113 { 1114 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1115 int err = -ENXIO; 1116 1117 if (neigh) { 1118 if (neigh->nud_state & ~NUD_NOARP) 1119 err = neigh_update(neigh, NULL, NUD_FAILED, 1120 NEIGH_UPDATE_F_OVERRIDE| 1121 NEIGH_UPDATE_F_ADMIN); 1122 neigh_release(neigh); 1123 } 1124 1125 return err; 1126 } 1127 EXPORT_SYMBOL(arp_invalidate); 1128 1129 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1130 struct net_device *dev) 1131 { 1132 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1133 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1134 1135 if (mask == htonl(0xFFFFFFFF)) 1136 return pneigh_delete(&arp_tbl, net, &ip, dev); 1137 1138 if (mask) 1139 return -EINVAL; 1140 1141 return arp_req_set_proxy(net, dev, 0); 1142 } 1143 1144 static int arp_req_delete(struct net *net, struct arpreq *r, 1145 struct net_device *dev) 1146 { 1147 __be32 ip; 1148 1149 if (r->arp_flags & ATF_PUBL) 1150 return arp_req_delete_public(net, r, dev); 1151 1152 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1153 if (dev == NULL) { 1154 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1155 if (IS_ERR(rt)) 1156 return PTR_ERR(rt); 1157 dev = rt->dst.dev; 1158 ip_rt_put(rt); 1159 if (!dev) 1160 return -EINVAL; 1161 } 1162 return arp_invalidate(dev, ip); 1163 } 1164 1165 /* 1166 * Handle an ARP layer I/O control request. 1167 */ 1168 1169 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1170 { 1171 int err; 1172 struct arpreq r; 1173 struct net_device *dev = NULL; 1174 1175 switch (cmd) { 1176 case SIOCDARP: 1177 case SIOCSARP: 1178 if (!capable(CAP_NET_ADMIN)) 1179 return -EPERM; 1180 case SIOCGARP: 1181 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1182 if (err) 1183 return -EFAULT; 1184 break; 1185 default: 1186 return -EINVAL; 1187 } 1188 1189 if (r.arp_pa.sa_family != AF_INET) 1190 return -EPFNOSUPPORT; 1191 1192 if (!(r.arp_flags & ATF_PUBL) && 1193 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1194 return -EINVAL; 1195 if (!(r.arp_flags & ATF_NETMASK)) 1196 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1197 htonl(0xFFFFFFFFUL); 1198 rtnl_lock(); 1199 if (r.arp_dev[0]) { 1200 err = -ENODEV; 1201 dev = __dev_get_by_name(net, r.arp_dev); 1202 if (dev == NULL) 1203 goto out; 1204 1205 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1206 if (!r.arp_ha.sa_family) 1207 r.arp_ha.sa_family = dev->type; 1208 err = -EINVAL; 1209 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1210 goto out; 1211 } else if (cmd == SIOCGARP) { 1212 err = -ENODEV; 1213 goto out; 1214 } 1215 1216 switch (cmd) { 1217 case SIOCDARP: 1218 err = arp_req_delete(net, &r, dev); 1219 break; 1220 case SIOCSARP: 1221 err = arp_req_set(net, &r, dev); 1222 break; 1223 case SIOCGARP: 1224 err = arp_req_get(&r, dev); 1225 break; 1226 } 1227 out: 1228 rtnl_unlock(); 1229 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1230 err = -EFAULT; 1231 return err; 1232 } 1233 1234 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1235 void *ptr) 1236 { 1237 struct net_device *dev = ptr; 1238 1239 switch (event) { 1240 case NETDEV_CHANGEADDR: 1241 neigh_changeaddr(&arp_tbl, dev); 1242 rt_cache_flush(dev_net(dev), 0); 1243 break; 1244 default: 1245 break; 1246 } 1247 1248 return NOTIFY_DONE; 1249 } 1250 1251 static struct notifier_block arp_netdev_notifier = { 1252 .notifier_call = arp_netdev_event, 1253 }; 1254 1255 /* Note, that it is not on notifier chain. 1256 It is necessary, that this routine was called after route cache will be 1257 flushed. 1258 */ 1259 void arp_ifdown(struct net_device *dev) 1260 { 1261 neigh_ifdown(&arp_tbl, dev); 1262 } 1263 1264 1265 /* 1266 * Called once on startup. 1267 */ 1268 1269 static struct packet_type arp_packet_type __read_mostly = { 1270 .type = cpu_to_be16(ETH_P_ARP), 1271 .func = arp_rcv, 1272 }; 1273 1274 static int arp_proc_init(void); 1275 1276 void __init arp_init(void) 1277 { 1278 neigh_table_init(&arp_tbl); 1279 1280 dev_add_pack(&arp_packet_type); 1281 arp_proc_init(); 1282 #ifdef CONFIG_SYSCTL 1283 neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL); 1284 #endif 1285 register_netdevice_notifier(&arp_netdev_notifier); 1286 } 1287 1288 #ifdef CONFIG_PROC_FS 1289 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1290 1291 /* ------------------------------------------------------------------------ */ 1292 /* 1293 * ax25 -> ASCII conversion 1294 */ 1295 static char *ax2asc2(ax25_address *a, char *buf) 1296 { 1297 char c, *s; 1298 int n; 1299 1300 for (n = 0, s = buf; n < 6; n++) { 1301 c = (a->ax25_call[n] >> 1) & 0x7F; 1302 1303 if (c != ' ') 1304 *s++ = c; 1305 } 1306 1307 *s++ = '-'; 1308 n = (a->ax25_call[6] >> 1) & 0x0F; 1309 if (n > 9) { 1310 *s++ = '1'; 1311 n -= 10; 1312 } 1313 1314 *s++ = n + '0'; 1315 *s++ = '\0'; 1316 1317 if (*buf == '\0' || *buf == '-') 1318 return "*"; 1319 1320 return buf; 1321 } 1322 #endif /* CONFIG_AX25 */ 1323 1324 #define HBUFFERLEN 30 1325 1326 static void arp_format_neigh_entry(struct seq_file *seq, 1327 struct neighbour *n) 1328 { 1329 char hbuffer[HBUFFERLEN]; 1330 int k, j; 1331 char tbuf[16]; 1332 struct net_device *dev = n->dev; 1333 int hatype = dev->type; 1334 1335 read_lock(&n->lock); 1336 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1337 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1338 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1339 ax2asc2((ax25_address *)n->ha, hbuffer); 1340 else { 1341 #endif 1342 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1343 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1344 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1345 hbuffer[k++] = ':'; 1346 } 1347 if (k != 0) 1348 --k; 1349 hbuffer[k] = 0; 1350 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 1351 } 1352 #endif 1353 sprintf(tbuf, "%pI4", n->primary_key); 1354 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1355 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1356 read_unlock(&n->lock); 1357 } 1358 1359 static void arp_format_pneigh_entry(struct seq_file *seq, 1360 struct pneigh_entry *n) 1361 { 1362 struct net_device *dev = n->dev; 1363 int hatype = dev ? dev->type : 0; 1364 char tbuf[16]; 1365 1366 sprintf(tbuf, "%pI4", n->key); 1367 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1368 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1369 dev ? dev->name : "*"); 1370 } 1371 1372 static int arp_seq_show(struct seq_file *seq, void *v) 1373 { 1374 if (v == SEQ_START_TOKEN) { 1375 seq_puts(seq, "IP address HW type Flags " 1376 "HW address Mask Device\n"); 1377 } else { 1378 struct neigh_seq_state *state = seq->private; 1379 1380 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1381 arp_format_pneigh_entry(seq, v); 1382 else 1383 arp_format_neigh_entry(seq, v); 1384 } 1385 1386 return 0; 1387 } 1388 1389 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1390 { 1391 /* Don't want to confuse "arp -a" w/ magic entries, 1392 * so we tell the generic iterator to skip NUD_NOARP. 1393 */ 1394 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1395 } 1396 1397 /* ------------------------------------------------------------------------ */ 1398 1399 static const struct seq_operations arp_seq_ops = { 1400 .start = arp_seq_start, 1401 .next = neigh_seq_next, 1402 .stop = neigh_seq_stop, 1403 .show = arp_seq_show, 1404 }; 1405 1406 static int arp_seq_open(struct inode *inode, struct file *file) 1407 { 1408 return seq_open_net(inode, file, &arp_seq_ops, 1409 sizeof(struct neigh_seq_state)); 1410 } 1411 1412 static const struct file_operations arp_seq_fops = { 1413 .owner = THIS_MODULE, 1414 .open = arp_seq_open, 1415 .read = seq_read, 1416 .llseek = seq_lseek, 1417 .release = seq_release_net, 1418 }; 1419 1420 1421 static int __net_init arp_net_init(struct net *net) 1422 { 1423 if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops)) 1424 return -ENOMEM; 1425 return 0; 1426 } 1427 1428 static void __net_exit arp_net_exit(struct net *net) 1429 { 1430 proc_net_remove(net, "arp"); 1431 } 1432 1433 static struct pernet_operations arp_net_ops = { 1434 .init = arp_net_init, 1435 .exit = arp_net_exit, 1436 }; 1437 1438 static int __init arp_proc_init(void) 1439 { 1440 return register_pernet_subsys(&arp_net_ops); 1441 } 1442 1443 #else /* CONFIG_PROC_FS */ 1444 1445 static int __init arp_proc_init(void) 1446 { 1447 return 0; 1448 } 1449 1450 #endif /* CONFIG_PROC_FS */ 1451