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> 115 116 #include <asm/system.h> 117 #include <linux/uaccess.h> 118 119 #include <linux/netfilter_arp.h> 120 121 /* 122 * Interface to generic neighbour cache. 123 */ 124 static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); 125 static int arp_constructor(struct neighbour *neigh); 126 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 127 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 128 static void parp_redo(struct sk_buff *skb); 129 130 static const struct neigh_ops arp_generic_ops = { 131 .family = AF_INET, 132 .solicit = arp_solicit, 133 .error_report = arp_error_report, 134 .output = neigh_resolve_output, 135 .connected_output = neigh_connected_output, 136 }; 137 138 static const struct neigh_ops arp_hh_ops = { 139 .family = AF_INET, 140 .solicit = arp_solicit, 141 .error_report = arp_error_report, 142 .output = neigh_resolve_output, 143 .connected_output = neigh_resolve_output, 144 }; 145 146 static const struct neigh_ops arp_direct_ops = { 147 .family = AF_INET, 148 .output = neigh_direct_output, 149 .connected_output = neigh_direct_output, 150 }; 151 152 static const struct neigh_ops arp_broken_ops = { 153 .family = AF_INET, 154 .solicit = arp_solicit, 155 .error_report = arp_error_report, 156 .output = neigh_compat_output, 157 .connected_output = neigh_compat_output, 158 }; 159 160 struct neigh_table arp_tbl = { 161 .family = AF_INET, 162 .key_len = 4, 163 .hash = arp_hash, 164 .constructor = arp_constructor, 165 .proxy_redo = parp_redo, 166 .id = "arp_cache", 167 .parms = { 168 .tbl = &arp_tbl, 169 .base_reachable_time = 30 * HZ, 170 .retrans_time = 1 * HZ, 171 .gc_staletime = 60 * HZ, 172 .reachable_time = 30 * HZ, 173 .delay_probe_time = 5 * HZ, 174 .queue_len_bytes = 64*1024, 175 .ucast_probes = 3, 176 .mcast_probes = 3, 177 .anycast_delay = 1 * HZ, 178 .proxy_delay = (8 * HZ) / 10, 179 .proxy_qlen = 64, 180 .locktime = 1 * HZ, 181 }, 182 .gc_interval = 30 * HZ, 183 .gc_thresh1 = 128, 184 .gc_thresh2 = 512, 185 .gc_thresh3 = 1024, 186 }; 187 EXPORT_SYMBOL(arp_tbl); 188 189 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 190 { 191 switch (dev->type) { 192 case ARPHRD_ETHER: 193 case ARPHRD_FDDI: 194 case ARPHRD_IEEE802: 195 ip_eth_mc_map(addr, haddr); 196 return 0; 197 case ARPHRD_IEEE802_TR: 198 ip_tr_mc_map(addr, haddr); 199 return 0; 200 case ARPHRD_INFINIBAND: 201 ip_ib_mc_map(addr, dev->broadcast, haddr); 202 return 0; 203 case ARPHRD_IPGRE: 204 ip_ipgre_mc_map(addr, dev->broadcast, haddr); 205 return 0; 206 default: 207 if (dir) { 208 memcpy(haddr, dev->broadcast, dev->addr_len); 209 return 0; 210 } 211 } 212 return -EINVAL; 213 } 214 215 216 static u32 arp_hash(const void *pkey, 217 const struct net_device *dev, 218 __u32 *hash_rnd) 219 { 220 return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd); 221 } 222 223 static int arp_constructor(struct neighbour *neigh) 224 { 225 __be32 addr = *(__be32 *)neigh->primary_key; 226 struct net_device *dev = neigh->dev; 227 struct in_device *in_dev; 228 struct neigh_parms *parms; 229 230 rcu_read_lock(); 231 in_dev = __in_dev_get_rcu(dev); 232 if (in_dev == NULL) { 233 rcu_read_unlock(); 234 return -EINVAL; 235 } 236 237 neigh->type = inet_addr_type(dev_net(dev), addr); 238 239 parms = in_dev->arp_parms; 240 __neigh_parms_put(neigh->parms); 241 neigh->parms = neigh_parms_clone(parms); 242 rcu_read_unlock(); 243 244 if (!dev->header_ops) { 245 neigh->nud_state = NUD_NOARP; 246 neigh->ops = &arp_direct_ops; 247 neigh->output = neigh_direct_output; 248 } else { 249 /* Good devices (checked by reading texts, but only Ethernet is 250 tested) 251 252 ARPHRD_ETHER: (ethernet, apfddi) 253 ARPHRD_FDDI: (fddi) 254 ARPHRD_IEEE802: (tr) 255 ARPHRD_METRICOM: (strip) 256 ARPHRD_ARCNET: 257 etc. etc. etc. 258 259 ARPHRD_IPDDP will also work, if author repairs it. 260 I did not it, because this driver does not work even 261 in old paradigm. 262 */ 263 264 #if 1 265 /* So... these "amateur" devices are hopeless. 266 The only thing, that I can say now: 267 It is very sad that we need to keep ugly obsolete 268 code to make them happy. 269 270 They should be moved to more reasonable state, now 271 they use rebuild_header INSTEAD OF hard_start_xmit!!! 272 Besides that, they are sort of out of date 273 (a lot of redundant clones/copies, useless in 2.1), 274 I wonder why people believe that they work. 275 */ 276 switch (dev->type) { 277 default: 278 break; 279 case ARPHRD_ROSE: 280 #if IS_ENABLED(CONFIG_AX25) 281 case ARPHRD_AX25: 282 #if IS_ENABLED(CONFIG_NETROM) 283 case ARPHRD_NETROM: 284 #endif 285 neigh->ops = &arp_broken_ops; 286 neigh->output = neigh->ops->output; 287 return 0; 288 #else 289 break; 290 #endif 291 } 292 #endif 293 if (neigh->type == RTN_MULTICAST) { 294 neigh->nud_state = NUD_NOARP; 295 arp_mc_map(addr, neigh->ha, dev, 1); 296 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 297 neigh->nud_state = NUD_NOARP; 298 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 299 } else if (neigh->type == RTN_BROADCAST || 300 (dev->flags & IFF_POINTOPOINT)) { 301 neigh->nud_state = NUD_NOARP; 302 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 303 } 304 305 if (dev->header_ops->cache) 306 neigh->ops = &arp_hh_ops; 307 else 308 neigh->ops = &arp_generic_ops; 309 310 if (neigh->nud_state & NUD_VALID) 311 neigh->output = neigh->ops->connected_output; 312 else 313 neigh->output = neigh->ops->output; 314 } 315 return 0; 316 } 317 318 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 319 { 320 dst_link_failure(skb); 321 kfree_skb(skb); 322 } 323 324 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 325 { 326 __be32 saddr = 0; 327 u8 *dst_ha = NULL; 328 struct net_device *dev = neigh->dev; 329 __be32 target = *(__be32 *)neigh->primary_key; 330 int probes = atomic_read(&neigh->probes); 331 struct in_device *in_dev; 332 333 rcu_read_lock(); 334 in_dev = __in_dev_get_rcu(dev); 335 if (!in_dev) { 336 rcu_read_unlock(); 337 return; 338 } 339 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 340 default: 341 case 0: /* By default announce any local IP */ 342 if (skb && inet_addr_type(dev_net(dev), 343 ip_hdr(skb)->saddr) == RTN_LOCAL) 344 saddr = ip_hdr(skb)->saddr; 345 break; 346 case 1: /* Restrict announcements of saddr in same subnet */ 347 if (!skb) 348 break; 349 saddr = ip_hdr(skb)->saddr; 350 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { 351 /* saddr should be known to target */ 352 if (inet_addr_onlink(in_dev, target, saddr)) 353 break; 354 } 355 saddr = 0; 356 break; 357 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 358 break; 359 } 360 rcu_read_unlock(); 361 362 if (!saddr) 363 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 364 365 probes -= neigh->parms->ucast_probes; 366 if (probes < 0) { 367 if (!(neigh->nud_state & NUD_VALID)) 368 printk(KERN_DEBUG 369 "trying to ucast probe in NUD_INVALID\n"); 370 dst_ha = neigh->ha; 371 read_lock_bh(&neigh->lock); 372 } else { 373 probes -= neigh->parms->app_probes; 374 if (probes < 0) { 375 #ifdef CONFIG_ARPD 376 neigh_app_ns(neigh); 377 #endif 378 return; 379 } 380 } 381 382 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 383 dst_ha, dev->dev_addr, NULL); 384 if (dst_ha) 385 read_unlock_bh(&neigh->lock); 386 } 387 388 static int arp_ignore(struct in_device *in_dev, __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 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(in_dev, sip, tip, scope); 420 } 421 422 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 423 { 424 struct rtable *rt; 425 int flag = 0; 426 /*unsigned long now; */ 427 struct net *net = dev_net(dev); 428 429 rt = ip_route_output(net, sip, tip, 0, 0); 430 if (IS_ERR(rt)) 431 return 1; 432 if (rt->dst.dev != dev) { 433 NET_INC_STATS_BH(net, 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, 452 __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(skb)) { 477 printk(KERN_DEBUG "arp_find is called with dst==NULL\n"); 478 kfree_skb(skb); 479 return 1; 480 } 481 482 paddr = skb_rtable(skb)->rt_gateway; 483 484 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, 485 paddr, dev)) 486 return 0; 487 488 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 489 490 if (n) { 491 n->used = jiffies; 492 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) { 493 neigh_ha_snapshot(haddr, n, dev); 494 neigh_release(n); 495 return 0; 496 } 497 neigh_release(n); 498 } else 499 kfree_skb(skb); 500 return 1; 501 } 502 EXPORT_SYMBOL(arp_find); 503 504 /* END OF OBSOLETE FUNCTIONS */ 505 506 /* 507 * Check if we can use proxy ARP for this path 508 */ 509 static inline int arp_fwd_proxy(struct in_device *in_dev, 510 struct net_device *dev, struct rtable *rt) 511 { 512 struct in_device *out_dev; 513 int imi, omi = -1; 514 515 if (rt->dst.dev == dev) 516 return 0; 517 518 if (!IN_DEV_PROXY_ARP(in_dev)) 519 return 0; 520 imi = IN_DEV_MEDIUM_ID(in_dev); 521 if (imi == 0) 522 return 1; 523 if (imi == -1) 524 return 0; 525 526 /* place to check for proxy_arp for routes */ 527 528 out_dev = __in_dev_get_rcu(rt->dst.dev); 529 if (out_dev) 530 omi = IN_DEV_MEDIUM_ID(out_dev); 531 532 return omi != imi && omi != -1; 533 } 534 535 /* 536 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 537 * 538 * RFC3069 supports proxy arp replies back to the same interface. This 539 * is done to support (ethernet) switch features, like RFC 3069, where 540 * the individual ports are not allowed to communicate with each 541 * other, BUT they are allowed to talk to the upstream router. As 542 * described in RFC 3069, it is possible to allow these hosts to 543 * communicate through the upstream router, by proxy_arp'ing. 544 * 545 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 546 * 547 * This technology is known by different names: 548 * In RFC 3069 it is called VLAN Aggregation. 549 * Cisco and Allied Telesyn call it Private VLAN. 550 * Hewlett-Packard call it Source-Port filtering or port-isolation. 551 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 552 * 553 */ 554 static inline int arp_fwd_pvlan(struct in_device *in_dev, 555 struct net_device *dev, struct rtable *rt, 556 __be32 sip, __be32 tip) 557 { 558 /* Private VLAN is only concerned about the same ethernet segment */ 559 if (rt->dst.dev != dev) 560 return 0; 561 562 /* Don't reply on self probes (often done by windowz boxes)*/ 563 if (sip == tip) 564 return 0; 565 566 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 567 return 1; 568 else 569 return 0; 570 } 571 572 /* 573 * Interface to link layer: send routine and receive handler. 574 */ 575 576 /* 577 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 578 * message. 579 */ 580 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 581 struct net_device *dev, __be32 src_ip, 582 const unsigned char *dest_hw, 583 const unsigned char *src_hw, 584 const unsigned char *target_hw) 585 { 586 struct sk_buff *skb; 587 struct arphdr *arp; 588 unsigned char *arp_ptr; 589 int hlen = LL_RESERVED_SPACE(dev); 590 int tlen = dev->needed_tailroom; 591 592 /* 593 * Allocate a buffer 594 */ 595 596 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 597 if (skb == NULL) 598 return NULL; 599 600 skb_reserve(skb, hlen); 601 skb_reset_network_header(skb); 602 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); 603 skb->dev = dev; 604 skb->protocol = htons(ETH_P_ARP); 605 if (src_hw == NULL) 606 src_hw = dev->dev_addr; 607 if (dest_hw == NULL) 608 dest_hw = dev->broadcast; 609 610 /* 611 * Fill the device header for the ARP frame 612 */ 613 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 614 goto out; 615 616 /* 617 * Fill out the arp protocol part. 618 * 619 * The arp hardware type should match the device type, except for FDDI, 620 * which (according to RFC 1390) should always equal 1 (Ethernet). 621 */ 622 /* 623 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 624 * DIX code for the protocol. Make these device structure fields. 625 */ 626 switch (dev->type) { 627 default: 628 arp->ar_hrd = htons(dev->type); 629 arp->ar_pro = htons(ETH_P_IP); 630 break; 631 632 #if IS_ENABLED(CONFIG_AX25) 633 case ARPHRD_AX25: 634 arp->ar_hrd = htons(ARPHRD_AX25); 635 arp->ar_pro = htons(AX25_P_IP); 636 break; 637 638 #if IS_ENABLED(CONFIG_NETROM) 639 case ARPHRD_NETROM: 640 arp->ar_hrd = htons(ARPHRD_NETROM); 641 arp->ar_pro = htons(AX25_P_IP); 642 break; 643 #endif 644 #endif 645 646 #if IS_ENABLED(CONFIG_FDDI) 647 case ARPHRD_FDDI: 648 arp->ar_hrd = htons(ARPHRD_ETHER); 649 arp->ar_pro = htons(ETH_P_IP); 650 break; 651 #endif 652 #if IS_ENABLED(CONFIG_TR) 653 case ARPHRD_IEEE802_TR: 654 arp->ar_hrd = htons(ARPHRD_IEEE802); 655 arp->ar_pro = htons(ETH_P_IP); 656 break; 657 #endif 658 } 659 660 arp->ar_hln = dev->addr_len; 661 arp->ar_pln = 4; 662 arp->ar_op = htons(type); 663 664 arp_ptr = (unsigned char *)(arp + 1); 665 666 memcpy(arp_ptr, src_hw, dev->addr_len); 667 arp_ptr += dev->addr_len; 668 memcpy(arp_ptr, &src_ip, 4); 669 arp_ptr += 4; 670 if (target_hw != NULL) 671 memcpy(arp_ptr, target_hw, dev->addr_len); 672 else 673 memset(arp_ptr, 0, dev->addr_len); 674 arp_ptr += dev->addr_len; 675 memcpy(arp_ptr, &dest_ip, 4); 676 677 return skb; 678 679 out: 680 kfree_skb(skb); 681 return NULL; 682 } 683 EXPORT_SYMBOL(arp_create); 684 685 /* 686 * Send an arp packet. 687 */ 688 void arp_xmit(struct sk_buff *skb) 689 { 690 /* Send it off, maybe filter it using firewalling first. */ 691 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 692 } 693 EXPORT_SYMBOL(arp_xmit); 694 695 /* 696 * Create and send an arp packet. 697 */ 698 void arp_send(int type, int ptype, __be32 dest_ip, 699 struct net_device *dev, __be32 src_ip, 700 const unsigned char *dest_hw, const unsigned char *src_hw, 701 const unsigned char *target_hw) 702 { 703 struct sk_buff *skb; 704 705 /* 706 * No arp on this interface. 707 */ 708 709 if (dev->flags&IFF_NOARP) 710 return; 711 712 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 713 dest_hw, src_hw, target_hw); 714 if (skb == NULL) 715 return; 716 717 arp_xmit(skb); 718 } 719 EXPORT_SYMBOL(arp_send); 720 721 /* 722 * Process an arp request. 723 */ 724 725 static int arp_process(struct sk_buff *skb) 726 { 727 struct net_device *dev = skb->dev; 728 struct in_device *in_dev = __in_dev_get_rcu(dev); 729 struct arphdr *arp; 730 unsigned char *arp_ptr; 731 struct rtable *rt; 732 unsigned char *sha; 733 __be32 sip, tip; 734 u16 dev_type = dev->type; 735 int addr_type; 736 struct neighbour *n; 737 struct net *net = dev_net(dev); 738 739 /* arp_rcv below verifies the ARP header and verifies the device 740 * is ARP'able. 741 */ 742 743 if (in_dev == NULL) 744 goto out; 745 746 arp = arp_hdr(skb); 747 748 switch (dev_type) { 749 default: 750 if (arp->ar_pro != htons(ETH_P_IP) || 751 htons(dev_type) != arp->ar_hrd) 752 goto out; 753 break; 754 case ARPHRD_ETHER: 755 case ARPHRD_IEEE802_TR: 756 case ARPHRD_FDDI: 757 case ARPHRD_IEEE802: 758 /* 759 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802 760 * devices, according to RFC 2625) devices will accept ARP 761 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 762 * This is the case also of FDDI, where the RFC 1390 says that 763 * FDDI devices should accept ARP hardware of (1) Ethernet, 764 * however, to be more robust, we'll accept both 1 (Ethernet) 765 * or 6 (IEEE 802.2) 766 */ 767 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 768 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 769 arp->ar_pro != htons(ETH_P_IP)) 770 goto out; 771 break; 772 case ARPHRD_AX25: 773 if (arp->ar_pro != htons(AX25_P_IP) || 774 arp->ar_hrd != htons(ARPHRD_AX25)) 775 goto out; 776 break; 777 case ARPHRD_NETROM: 778 if (arp->ar_pro != htons(AX25_P_IP) || 779 arp->ar_hrd != htons(ARPHRD_NETROM)) 780 goto out; 781 break; 782 } 783 784 /* Understand only these message types */ 785 786 if (arp->ar_op != htons(ARPOP_REPLY) && 787 arp->ar_op != htons(ARPOP_REQUEST)) 788 goto out; 789 790 /* 791 * Extract fields 792 */ 793 arp_ptr = (unsigned char *)(arp + 1); 794 sha = arp_ptr; 795 arp_ptr += dev->addr_len; 796 memcpy(&sip, arp_ptr, 4); 797 arp_ptr += 4; 798 arp_ptr += dev->addr_len; 799 memcpy(&tip, arp_ptr, 4); 800 /* 801 * Check for bad requests for 127.x.x.x and requests for multicast 802 * addresses. If this is one such, delete it. 803 */ 804 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip)) 805 goto out; 806 807 /* 808 * Special case: We must set Frame Relay source Q.922 address 809 */ 810 if (dev_type == ARPHRD_DLCI) 811 sha = dev->broadcast; 812 813 /* 814 * Process entry. The idea here is we want to send a reply if it is a 815 * request for us or if it is a request for someone else that we hold 816 * a proxy for. We want to add an entry to our cache if it is a reply 817 * to us or if it is a request for our address. 818 * (The assumption for this last is that if someone is requesting our 819 * address, they are probably intending to talk to us, so it saves time 820 * if we cache their address. Their address is also probably not in 821 * our cache, since ours is not in their cache.) 822 * 823 * Putting this another way, we only care about replies if they are to 824 * us, in which case we add them to the cache. For requests, we care 825 * about those for us and those for our proxies. We reply to both, 826 * and in the case of requests for us we add the requester to the arp 827 * cache. 828 */ 829 830 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 831 if (sip == 0) { 832 if (arp->ar_op == htons(ARPOP_REQUEST) && 833 inet_addr_type(net, tip) == RTN_LOCAL && 834 !arp_ignore(in_dev, sip, tip)) 835 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, 836 dev->dev_addr, sha); 837 goto out; 838 } 839 840 if (arp->ar_op == htons(ARPOP_REQUEST) && 841 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 842 843 rt = skb_rtable(skb); 844 addr_type = rt->rt_type; 845 846 if (addr_type == RTN_LOCAL) { 847 int dont_send; 848 849 dont_send = arp_ignore(in_dev, sip, tip); 850 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 851 dont_send = arp_filter(sip, tip, dev); 852 if (!dont_send) { 853 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 854 if (n) { 855 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 856 dev, tip, sha, dev->dev_addr, 857 sha); 858 neigh_release(n); 859 } 860 } 861 goto out; 862 } else if (IN_DEV_FORWARD(in_dev)) { 863 if (addr_type == RTN_UNICAST && 864 (arp_fwd_proxy(in_dev, dev, rt) || 865 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 866 pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) { 867 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 868 if (n) 869 neigh_release(n); 870 871 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 872 skb->pkt_type == PACKET_HOST || 873 in_dev->arp_parms->proxy_delay == 0) { 874 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 875 dev, tip, sha, dev->dev_addr, 876 sha); 877 } else { 878 pneigh_enqueue(&arp_tbl, 879 in_dev->arp_parms, skb); 880 return 0; 881 } 882 goto out; 883 } 884 } 885 } 886 887 /* Update our ARP tables */ 888 889 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 890 891 if (IPV4_DEVCONF_ALL(dev_net(dev), ARP_ACCEPT)) { 892 /* Unsolicited ARP is not accepted by default. 893 It is possible, that this option should be enabled for some 894 devices (strip is candidate) 895 */ 896 if (n == NULL && 897 (arp->ar_op == htons(ARPOP_REPLY) || 898 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) && 899 inet_addr_type(net, sip) == RTN_UNICAST) 900 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 901 } 902 903 if (n) { 904 int state = NUD_REACHABLE; 905 int override; 906 907 /* If several different ARP replies follows back-to-back, 908 use the FIRST one. It is possible, if several proxy 909 agents are active. Taking the first reply prevents 910 arp trashing and chooses the fastest router. 911 */ 912 override = time_after(jiffies, n->updated + n->parms->locktime); 913 914 /* Broadcast replies and request packets 915 do not assert neighbour reachability. 916 */ 917 if (arp->ar_op != htons(ARPOP_REPLY) || 918 skb->pkt_type != PACKET_HOST) 919 state = NUD_STALE; 920 neigh_update(n, sha, state, 921 override ? NEIGH_UPDATE_F_OVERRIDE : 0); 922 neigh_release(n); 923 } 924 925 out: 926 consume_skb(skb); 927 return 0; 928 } 929 930 static void parp_redo(struct sk_buff *skb) 931 { 932 arp_process(skb); 933 } 934 935 936 /* 937 * Receive an arp request from the device layer. 938 */ 939 940 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 941 struct packet_type *pt, struct net_device *orig_dev) 942 { 943 struct arphdr *arp; 944 945 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 946 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 947 goto freeskb; 948 949 arp = arp_hdr(skb); 950 if (arp->ar_hln != dev->addr_len || 951 dev->flags & IFF_NOARP || 952 skb->pkt_type == PACKET_OTHERHOST || 953 skb->pkt_type == PACKET_LOOPBACK || 954 arp->ar_pln != 4) 955 goto freeskb; 956 957 skb = skb_share_check(skb, GFP_ATOMIC); 958 if (skb == NULL) 959 goto out_of_mem; 960 961 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 962 963 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 964 965 freeskb: 966 kfree_skb(skb); 967 out_of_mem: 968 return 0; 969 } 970 971 /* 972 * User level interface (ioctl) 973 */ 974 975 /* 976 * Set (create) an ARP cache entry. 977 */ 978 979 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 980 { 981 if (dev == NULL) { 982 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 983 return 0; 984 } 985 if (__in_dev_get_rtnl(dev)) { 986 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 987 return 0; 988 } 989 return -ENXIO; 990 } 991 992 static int arp_req_set_public(struct net *net, struct arpreq *r, 993 struct net_device *dev) 994 { 995 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 996 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 997 998 if (mask && mask != htonl(0xFFFFFFFF)) 999 return -EINVAL; 1000 if (!dev && (r->arp_flags & ATF_COM)) { 1001 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 1002 r->arp_ha.sa_data); 1003 if (!dev) 1004 return -ENODEV; 1005 } 1006 if (mask) { 1007 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL) 1008 return -ENOBUFS; 1009 return 0; 1010 } 1011 1012 return arp_req_set_proxy(net, dev, 1); 1013 } 1014 1015 static int arp_req_set(struct net *net, struct arpreq *r, 1016 struct net_device *dev) 1017 { 1018 __be32 ip; 1019 struct neighbour *neigh; 1020 int err; 1021 1022 if (r->arp_flags & ATF_PUBL) 1023 return arp_req_set_public(net, r, dev); 1024 1025 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1026 if (r->arp_flags & ATF_PERM) 1027 r->arp_flags |= ATF_COM; 1028 if (dev == NULL) { 1029 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1030 1031 if (IS_ERR(rt)) 1032 return PTR_ERR(rt); 1033 dev = rt->dst.dev; 1034 ip_rt_put(rt); 1035 if (!dev) 1036 return -EINVAL; 1037 } 1038 switch (dev->type) { 1039 #if IS_ENABLED(CONFIG_FDDI) 1040 case ARPHRD_FDDI: 1041 /* 1042 * According to RFC 1390, FDDI devices should accept ARP 1043 * hardware types of 1 (Ethernet). However, to be more 1044 * robust, we'll accept hardware types of either 1 (Ethernet) 1045 * or 6 (IEEE 802.2). 1046 */ 1047 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1048 r->arp_ha.sa_family != ARPHRD_ETHER && 1049 r->arp_ha.sa_family != ARPHRD_IEEE802) 1050 return -EINVAL; 1051 break; 1052 #endif 1053 default: 1054 if (r->arp_ha.sa_family != dev->type) 1055 return -EINVAL; 1056 break; 1057 } 1058 1059 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1060 err = PTR_ERR(neigh); 1061 if (!IS_ERR(neigh)) { 1062 unsigned state = NUD_STALE; 1063 if (r->arp_flags & ATF_PERM) 1064 state = NUD_PERMANENT; 1065 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1066 r->arp_ha.sa_data : NULL, state, 1067 NEIGH_UPDATE_F_OVERRIDE | 1068 NEIGH_UPDATE_F_ADMIN); 1069 neigh_release(neigh); 1070 } 1071 return err; 1072 } 1073 1074 static unsigned arp_state_to_flags(struct neighbour *neigh) 1075 { 1076 if (neigh->nud_state&NUD_PERMANENT) 1077 return ATF_PERM | ATF_COM; 1078 else if (neigh->nud_state&NUD_VALID) 1079 return ATF_COM; 1080 else 1081 return 0; 1082 } 1083 1084 /* 1085 * Get an ARP cache entry. 1086 */ 1087 1088 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1089 { 1090 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1091 struct neighbour *neigh; 1092 int err = -ENXIO; 1093 1094 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1095 if (neigh) { 1096 read_lock_bh(&neigh->lock); 1097 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1098 r->arp_flags = arp_state_to_flags(neigh); 1099 read_unlock_bh(&neigh->lock); 1100 r->arp_ha.sa_family = dev->type; 1101 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1102 neigh_release(neigh); 1103 err = 0; 1104 } 1105 return err; 1106 } 1107 1108 int arp_invalidate(struct net_device *dev, __be32 ip) 1109 { 1110 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1111 int err = -ENXIO; 1112 1113 if (neigh) { 1114 if (neigh->nud_state & ~NUD_NOARP) 1115 err = neigh_update(neigh, NULL, NUD_FAILED, 1116 NEIGH_UPDATE_F_OVERRIDE| 1117 NEIGH_UPDATE_F_ADMIN); 1118 neigh_release(neigh); 1119 } 1120 1121 return err; 1122 } 1123 EXPORT_SYMBOL(arp_invalidate); 1124 1125 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1126 struct net_device *dev) 1127 { 1128 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1129 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1130 1131 if (mask == htonl(0xFFFFFFFF)) 1132 return pneigh_delete(&arp_tbl, net, &ip, dev); 1133 1134 if (mask) 1135 return -EINVAL; 1136 1137 return arp_req_set_proxy(net, dev, 0); 1138 } 1139 1140 static int arp_req_delete(struct net *net, struct arpreq *r, 1141 struct net_device *dev) 1142 { 1143 __be32 ip; 1144 1145 if (r->arp_flags & ATF_PUBL) 1146 return arp_req_delete_public(net, r, dev); 1147 1148 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1149 if (dev == NULL) { 1150 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1151 if (IS_ERR(rt)) 1152 return PTR_ERR(rt); 1153 dev = rt->dst.dev; 1154 ip_rt_put(rt); 1155 if (!dev) 1156 return -EINVAL; 1157 } 1158 return arp_invalidate(dev, ip); 1159 } 1160 1161 /* 1162 * Handle an ARP layer I/O control request. 1163 */ 1164 1165 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1166 { 1167 int err; 1168 struct arpreq r; 1169 struct net_device *dev = NULL; 1170 1171 switch (cmd) { 1172 case SIOCDARP: 1173 case SIOCSARP: 1174 if (!capable(CAP_NET_ADMIN)) 1175 return -EPERM; 1176 case SIOCGARP: 1177 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1178 if (err) 1179 return -EFAULT; 1180 break; 1181 default: 1182 return -EINVAL; 1183 } 1184 1185 if (r.arp_pa.sa_family != AF_INET) 1186 return -EPFNOSUPPORT; 1187 1188 if (!(r.arp_flags & ATF_PUBL) && 1189 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1190 return -EINVAL; 1191 if (!(r.arp_flags & ATF_NETMASK)) 1192 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1193 htonl(0xFFFFFFFFUL); 1194 rtnl_lock(); 1195 if (r.arp_dev[0]) { 1196 err = -ENODEV; 1197 dev = __dev_get_by_name(net, r.arp_dev); 1198 if (dev == NULL) 1199 goto out; 1200 1201 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1202 if (!r.arp_ha.sa_family) 1203 r.arp_ha.sa_family = dev->type; 1204 err = -EINVAL; 1205 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1206 goto out; 1207 } else if (cmd == SIOCGARP) { 1208 err = -ENODEV; 1209 goto out; 1210 } 1211 1212 switch (cmd) { 1213 case SIOCDARP: 1214 err = arp_req_delete(net, &r, dev); 1215 break; 1216 case SIOCSARP: 1217 err = arp_req_set(net, &r, dev); 1218 break; 1219 case SIOCGARP: 1220 err = arp_req_get(&r, dev); 1221 break; 1222 } 1223 out: 1224 rtnl_unlock(); 1225 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1226 err = -EFAULT; 1227 return err; 1228 } 1229 1230 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1231 void *ptr) 1232 { 1233 struct net_device *dev = ptr; 1234 1235 switch (event) { 1236 case NETDEV_CHANGEADDR: 1237 neigh_changeaddr(&arp_tbl, dev); 1238 rt_cache_flush(dev_net(dev), 0); 1239 break; 1240 default: 1241 break; 1242 } 1243 1244 return NOTIFY_DONE; 1245 } 1246 1247 static struct notifier_block arp_netdev_notifier = { 1248 .notifier_call = arp_netdev_event, 1249 }; 1250 1251 /* Note, that it is not on notifier chain. 1252 It is necessary, that this routine was called after route cache will be 1253 flushed. 1254 */ 1255 void arp_ifdown(struct net_device *dev) 1256 { 1257 neigh_ifdown(&arp_tbl, dev); 1258 } 1259 1260 1261 /* 1262 * Called once on startup. 1263 */ 1264 1265 static struct packet_type arp_packet_type __read_mostly = { 1266 .type = cpu_to_be16(ETH_P_ARP), 1267 .func = arp_rcv, 1268 }; 1269 1270 static int arp_proc_init(void); 1271 1272 void __init arp_init(void) 1273 { 1274 neigh_table_init(&arp_tbl); 1275 1276 dev_add_pack(&arp_packet_type); 1277 arp_proc_init(); 1278 #ifdef CONFIG_SYSCTL 1279 neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL); 1280 #endif 1281 register_netdevice_notifier(&arp_netdev_notifier); 1282 } 1283 1284 #ifdef CONFIG_PROC_FS 1285 #if IS_ENABLED(CONFIG_AX25) 1286 1287 /* ------------------------------------------------------------------------ */ 1288 /* 1289 * ax25 -> ASCII conversion 1290 */ 1291 static char *ax2asc2(ax25_address *a, char *buf) 1292 { 1293 char c, *s; 1294 int n; 1295 1296 for (n = 0, s = buf; n < 6; n++) { 1297 c = (a->ax25_call[n] >> 1) & 0x7F; 1298 1299 if (c != ' ') 1300 *s++ = c; 1301 } 1302 1303 *s++ = '-'; 1304 n = (a->ax25_call[6] >> 1) & 0x0F; 1305 if (n > 9) { 1306 *s++ = '1'; 1307 n -= 10; 1308 } 1309 1310 *s++ = n + '0'; 1311 *s++ = '\0'; 1312 1313 if (*buf == '\0' || *buf == '-') 1314 return "*"; 1315 1316 return buf; 1317 } 1318 #endif /* CONFIG_AX25 */ 1319 1320 #define HBUFFERLEN 30 1321 1322 static void arp_format_neigh_entry(struct seq_file *seq, 1323 struct neighbour *n) 1324 { 1325 char hbuffer[HBUFFERLEN]; 1326 int k, j; 1327 char tbuf[16]; 1328 struct net_device *dev = n->dev; 1329 int hatype = dev->type; 1330 1331 read_lock(&n->lock); 1332 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1333 #if IS_ENABLED(CONFIG_AX25) 1334 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1335 ax2asc2((ax25_address *)n->ha, hbuffer); 1336 else { 1337 #endif 1338 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1339 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1340 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1341 hbuffer[k++] = ':'; 1342 } 1343 if (k != 0) 1344 --k; 1345 hbuffer[k] = 0; 1346 #if IS_ENABLED(CONFIG_AX25) 1347 } 1348 #endif 1349 sprintf(tbuf, "%pI4", n->primary_key); 1350 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1351 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1352 read_unlock(&n->lock); 1353 } 1354 1355 static void arp_format_pneigh_entry(struct seq_file *seq, 1356 struct pneigh_entry *n) 1357 { 1358 struct net_device *dev = n->dev; 1359 int hatype = dev ? dev->type : 0; 1360 char tbuf[16]; 1361 1362 sprintf(tbuf, "%pI4", n->key); 1363 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1364 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1365 dev ? dev->name : "*"); 1366 } 1367 1368 static int arp_seq_show(struct seq_file *seq, void *v) 1369 { 1370 if (v == SEQ_START_TOKEN) { 1371 seq_puts(seq, "IP address HW type Flags " 1372 "HW address Mask Device\n"); 1373 } else { 1374 struct neigh_seq_state *state = seq->private; 1375 1376 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1377 arp_format_pneigh_entry(seq, v); 1378 else 1379 arp_format_neigh_entry(seq, v); 1380 } 1381 1382 return 0; 1383 } 1384 1385 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1386 { 1387 /* Don't want to confuse "arp -a" w/ magic entries, 1388 * so we tell the generic iterator to skip NUD_NOARP. 1389 */ 1390 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1391 } 1392 1393 /* ------------------------------------------------------------------------ */ 1394 1395 static const struct seq_operations arp_seq_ops = { 1396 .start = arp_seq_start, 1397 .next = neigh_seq_next, 1398 .stop = neigh_seq_stop, 1399 .show = arp_seq_show, 1400 }; 1401 1402 static int arp_seq_open(struct inode *inode, struct file *file) 1403 { 1404 return seq_open_net(inode, file, &arp_seq_ops, 1405 sizeof(struct neigh_seq_state)); 1406 } 1407 1408 static const struct file_operations arp_seq_fops = { 1409 .owner = THIS_MODULE, 1410 .open = arp_seq_open, 1411 .read = seq_read, 1412 .llseek = seq_lseek, 1413 .release = seq_release_net, 1414 }; 1415 1416 1417 static int __net_init arp_net_init(struct net *net) 1418 { 1419 if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops)) 1420 return -ENOMEM; 1421 return 0; 1422 } 1423 1424 static void __net_exit arp_net_exit(struct net *net) 1425 { 1426 proc_net_remove(net, "arp"); 1427 } 1428 1429 static struct pernet_operations arp_net_ops = { 1430 .init = arp_net_init, 1431 .exit = arp_net_exit, 1432 }; 1433 1434 static int __init arp_proc_init(void) 1435 { 1436 return register_pernet_subsys(&arp_net_ops); 1437 } 1438 1439 #else /* CONFIG_PROC_FS */ 1440 1441 static int __init arp_proc_init(void) 1442 { 1443 return 0; 1444 } 1445 1446 #endif /* CONFIG_PROC_FS */ 1447