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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 77 78 #include <linux/module.h> 79 #include <linux/types.h> 80 #include <linux/string.h> 81 #include <linux/kernel.h> 82 #include <linux/capability.h> 83 #include <linux/socket.h> 84 #include <linux/sockios.h> 85 #include <linux/errno.h> 86 #include <linux/in.h> 87 #include <linux/mm.h> 88 #include <linux/inet.h> 89 #include <linux/inetdevice.h> 90 #include <linux/netdevice.h> 91 #include <linux/etherdevice.h> 92 #include <linux/fddidevice.h> 93 #include <linux/if_arp.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/slab.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 #include <net/ax25.h> 115 #include <net/netrom.h> 116 117 #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_INFINIBAND: 198 ip_ib_mc_map(addr, dev->broadcast, haddr); 199 return 0; 200 case ARPHRD_IPGRE: 201 ip_ipgre_mc_map(addr, dev->broadcast, haddr); 202 return 0; 203 default: 204 if (dir) { 205 memcpy(haddr, dev->broadcast, dev->addr_len); 206 return 0; 207 } 208 } 209 return -EINVAL; 210 } 211 212 213 static u32 arp_hash(const void *pkey, 214 const struct net_device *dev, 215 __u32 *hash_rnd) 216 { 217 return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd); 218 } 219 220 static int arp_constructor(struct neighbour *neigh) 221 { 222 __be32 addr = *(__be32 *)neigh->primary_key; 223 struct net_device *dev = neigh->dev; 224 struct in_device *in_dev; 225 struct neigh_parms *parms; 226 227 rcu_read_lock(); 228 in_dev = __in_dev_get_rcu(dev); 229 if (in_dev == NULL) { 230 rcu_read_unlock(); 231 return -EINVAL; 232 } 233 234 neigh->type = inet_addr_type(dev_net(dev), addr); 235 236 parms = in_dev->arp_parms; 237 __neigh_parms_put(neigh->parms); 238 neigh->parms = neigh_parms_clone(parms); 239 rcu_read_unlock(); 240 241 if (!dev->header_ops) { 242 neigh->nud_state = NUD_NOARP; 243 neigh->ops = &arp_direct_ops; 244 neigh->output = neigh_direct_output; 245 } else { 246 /* Good devices (checked by reading texts, but only Ethernet is 247 tested) 248 249 ARPHRD_ETHER: (ethernet, apfddi) 250 ARPHRD_FDDI: (fddi) 251 ARPHRD_IEEE802: (tr) 252 ARPHRD_METRICOM: (strip) 253 ARPHRD_ARCNET: 254 etc. etc. etc. 255 256 ARPHRD_IPDDP will also work, if author repairs it. 257 I did not it, because this driver does not work even 258 in old paradigm. 259 */ 260 261 #if 1 262 /* So... these "amateur" devices are hopeless. 263 The only thing, that I can say now: 264 It is very sad that we need to keep ugly obsolete 265 code to make them happy. 266 267 They should be moved to more reasonable state, now 268 they use rebuild_header INSTEAD OF hard_start_xmit!!! 269 Besides that, they are sort of out of date 270 (a lot of redundant clones/copies, useless in 2.1), 271 I wonder why people believe that they work. 272 */ 273 switch (dev->type) { 274 default: 275 break; 276 case ARPHRD_ROSE: 277 #if IS_ENABLED(CONFIG_AX25) 278 case ARPHRD_AX25: 279 #if IS_ENABLED(CONFIG_NETROM) 280 case ARPHRD_NETROM: 281 #endif 282 neigh->ops = &arp_broken_ops; 283 neigh->output = neigh->ops->output; 284 return 0; 285 #else 286 break; 287 #endif 288 } 289 #endif 290 if (neigh->type == RTN_MULTICAST) { 291 neigh->nud_state = NUD_NOARP; 292 arp_mc_map(addr, neigh->ha, dev, 1); 293 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 294 neigh->nud_state = NUD_NOARP; 295 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 296 } else if (neigh->type == RTN_BROADCAST || 297 (dev->flags & IFF_POINTOPOINT)) { 298 neigh->nud_state = NUD_NOARP; 299 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 300 } 301 302 if (dev->header_ops->cache) 303 neigh->ops = &arp_hh_ops; 304 else 305 neigh->ops = &arp_generic_ops; 306 307 if (neigh->nud_state & NUD_VALID) 308 neigh->output = neigh->ops->connected_output; 309 else 310 neigh->output = neigh->ops->output; 311 } 312 return 0; 313 } 314 315 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 316 { 317 dst_link_failure(skb); 318 kfree_skb(skb); 319 } 320 321 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 322 { 323 __be32 saddr = 0; 324 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL; 325 struct net_device *dev = neigh->dev; 326 __be32 target = *(__be32 *)neigh->primary_key; 327 int probes = atomic_read(&neigh->probes); 328 struct in_device *in_dev; 329 330 rcu_read_lock(); 331 in_dev = __in_dev_get_rcu(dev); 332 if (!in_dev) { 333 rcu_read_unlock(); 334 return; 335 } 336 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 337 default: 338 case 0: /* By default announce any local IP */ 339 if (skb && inet_addr_type(dev_net(dev), 340 ip_hdr(skb)->saddr) == RTN_LOCAL) 341 saddr = ip_hdr(skb)->saddr; 342 break; 343 case 1: /* Restrict announcements of saddr in same subnet */ 344 if (!skb) 345 break; 346 saddr = ip_hdr(skb)->saddr; 347 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { 348 /* saddr should be known to target */ 349 if (inet_addr_onlink(in_dev, target, saddr)) 350 break; 351 } 352 saddr = 0; 353 break; 354 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 355 break; 356 } 357 rcu_read_unlock(); 358 359 if (!saddr) 360 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 361 362 probes -= neigh->parms->ucast_probes; 363 if (probes < 0) { 364 if (!(neigh->nud_state & NUD_VALID)) 365 pr_debug("trying to ucast probe in NUD_INVALID\n"); 366 neigh_ha_snapshot(dst_ha, neigh, dev); 367 dst_hw = dst_ha; 368 } else { 369 probes -= neigh->parms->app_probes; 370 if (probes < 0) { 371 #ifdef CONFIG_ARPD 372 neigh_app_ns(neigh); 373 #endif 374 return; 375 } 376 } 377 378 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 379 dst_hw, dev->dev_addr, NULL); 380 } 381 382 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 383 { 384 int scope; 385 386 switch (IN_DEV_ARP_IGNORE(in_dev)) { 387 case 0: /* Reply, the tip is already validated */ 388 return 0; 389 case 1: /* Reply only if tip is configured on the incoming interface */ 390 sip = 0; 391 scope = RT_SCOPE_HOST; 392 break; 393 case 2: /* 394 * Reply only if tip is configured on the incoming interface 395 * and is in same subnet as sip 396 */ 397 scope = RT_SCOPE_HOST; 398 break; 399 case 3: /* Do not reply for scope host addresses */ 400 sip = 0; 401 scope = RT_SCOPE_LINK; 402 break; 403 case 4: /* Reserved */ 404 case 5: 405 case 6: 406 case 7: 407 return 0; 408 case 8: /* Do not reply */ 409 return 1; 410 default: 411 return 0; 412 } 413 return !inet_confirm_addr(in_dev, sip, tip, scope); 414 } 415 416 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 417 { 418 struct rtable *rt; 419 int flag = 0; 420 /*unsigned long now; */ 421 struct net *net = dev_net(dev); 422 423 rt = ip_route_output(net, sip, tip, 0, 0); 424 if (IS_ERR(rt)) 425 return 1; 426 if (rt->dst.dev != dev) { 427 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); 428 flag = 1; 429 } 430 ip_rt_put(rt); 431 return flag; 432 } 433 434 /* OBSOLETE FUNCTIONS */ 435 436 /* 437 * Find an arp mapping in the cache. If not found, post a request. 438 * 439 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 440 * even if it exists. It is supposed that skb->dev was mangled 441 * by a virtual device (eql, shaper). Nobody but broken devices 442 * is allowed to use this function, it is scheduled to be removed. --ANK 443 */ 444 445 static int arp_set_predefined(int addr_hint, unsigned char *haddr, 446 __be32 paddr, struct net_device *dev) 447 { 448 switch (addr_hint) { 449 case RTN_LOCAL: 450 pr_debug("arp called for own IP address\n"); 451 memcpy(haddr, dev->dev_addr, dev->addr_len); 452 return 1; 453 case RTN_MULTICAST: 454 arp_mc_map(paddr, haddr, dev, 1); 455 return 1; 456 case RTN_BROADCAST: 457 memcpy(haddr, dev->broadcast, dev->addr_len); 458 return 1; 459 } 460 return 0; 461 } 462 463 464 int arp_find(unsigned char *haddr, struct sk_buff *skb) 465 { 466 struct net_device *dev = skb->dev; 467 __be32 paddr; 468 struct neighbour *n; 469 470 if (!skb_dst(skb)) { 471 pr_debug("arp_find is called with dst==NULL\n"); 472 kfree_skb(skb); 473 return 1; 474 } 475 476 paddr = rt_nexthop(skb_rtable(skb), ip_hdr(skb)->daddr); 477 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, 478 paddr, dev)) 479 return 0; 480 481 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 482 483 if (n) { 484 n->used = jiffies; 485 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) { 486 neigh_ha_snapshot(haddr, n, dev); 487 neigh_release(n); 488 return 0; 489 } 490 neigh_release(n); 491 } else 492 kfree_skb(skb); 493 return 1; 494 } 495 EXPORT_SYMBOL(arp_find); 496 497 /* END OF OBSOLETE FUNCTIONS */ 498 499 /* 500 * Check if we can use proxy ARP for this path 501 */ 502 static inline int arp_fwd_proxy(struct in_device *in_dev, 503 struct net_device *dev, struct rtable *rt) 504 { 505 struct in_device *out_dev; 506 int imi, omi = -1; 507 508 if (rt->dst.dev == dev) 509 return 0; 510 511 if (!IN_DEV_PROXY_ARP(in_dev)) 512 return 0; 513 imi = IN_DEV_MEDIUM_ID(in_dev); 514 if (imi == 0) 515 return 1; 516 if (imi == -1) 517 return 0; 518 519 /* place to check for proxy_arp for routes */ 520 521 out_dev = __in_dev_get_rcu(rt->dst.dev); 522 if (out_dev) 523 omi = IN_DEV_MEDIUM_ID(out_dev); 524 525 return omi != imi && omi != -1; 526 } 527 528 /* 529 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 530 * 531 * RFC3069 supports proxy arp replies back to the same interface. This 532 * is done to support (ethernet) switch features, like RFC 3069, where 533 * the individual ports are not allowed to communicate with each 534 * other, BUT they are allowed to talk to the upstream router. As 535 * described in RFC 3069, it is possible to allow these hosts to 536 * communicate through the upstream router, by proxy_arp'ing. 537 * 538 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 539 * 540 * This technology is known by different names: 541 * In RFC 3069 it is called VLAN Aggregation. 542 * Cisco and Allied Telesyn call it Private VLAN. 543 * Hewlett-Packard call it Source-Port filtering or port-isolation. 544 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 545 * 546 */ 547 static inline int arp_fwd_pvlan(struct in_device *in_dev, 548 struct net_device *dev, struct rtable *rt, 549 __be32 sip, __be32 tip) 550 { 551 /* Private VLAN is only concerned about the same ethernet segment */ 552 if (rt->dst.dev != dev) 553 return 0; 554 555 /* Don't reply on self probes (often done by windowz boxes)*/ 556 if (sip == tip) 557 return 0; 558 559 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 560 return 1; 561 else 562 return 0; 563 } 564 565 /* 566 * Interface to link layer: send routine and receive handler. 567 */ 568 569 /* 570 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 571 * message. 572 */ 573 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 574 struct net_device *dev, __be32 src_ip, 575 const unsigned char *dest_hw, 576 const unsigned char *src_hw, 577 const unsigned char *target_hw) 578 { 579 struct sk_buff *skb; 580 struct arphdr *arp; 581 unsigned char *arp_ptr; 582 int hlen = LL_RESERVED_SPACE(dev); 583 int tlen = dev->needed_tailroom; 584 585 /* 586 * Allocate a buffer 587 */ 588 589 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 590 if (skb == NULL) 591 return NULL; 592 593 skb_reserve(skb, hlen); 594 skb_reset_network_header(skb); 595 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); 596 skb->dev = dev; 597 skb->protocol = htons(ETH_P_ARP); 598 if (src_hw == NULL) 599 src_hw = dev->dev_addr; 600 if (dest_hw == NULL) 601 dest_hw = dev->broadcast; 602 603 /* 604 * Fill the device header for the ARP frame 605 */ 606 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 607 goto out; 608 609 /* 610 * Fill out the arp protocol part. 611 * 612 * The arp hardware type should match the device type, except for FDDI, 613 * which (according to RFC 1390) should always equal 1 (Ethernet). 614 */ 615 /* 616 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 617 * DIX code for the protocol. Make these device structure fields. 618 */ 619 switch (dev->type) { 620 default: 621 arp->ar_hrd = htons(dev->type); 622 arp->ar_pro = htons(ETH_P_IP); 623 break; 624 625 #if IS_ENABLED(CONFIG_AX25) 626 case ARPHRD_AX25: 627 arp->ar_hrd = htons(ARPHRD_AX25); 628 arp->ar_pro = htons(AX25_P_IP); 629 break; 630 631 #if IS_ENABLED(CONFIG_NETROM) 632 case ARPHRD_NETROM: 633 arp->ar_hrd = htons(ARPHRD_NETROM); 634 arp->ar_pro = htons(AX25_P_IP); 635 break; 636 #endif 637 #endif 638 639 #if IS_ENABLED(CONFIG_FDDI) 640 case ARPHRD_FDDI: 641 arp->ar_hrd = htons(ARPHRD_ETHER); 642 arp->ar_pro = htons(ETH_P_IP); 643 break; 644 #endif 645 } 646 647 arp->ar_hln = dev->addr_len; 648 arp->ar_pln = 4; 649 arp->ar_op = htons(type); 650 651 arp_ptr = (unsigned char *)(arp + 1); 652 653 memcpy(arp_ptr, src_hw, dev->addr_len); 654 arp_ptr += dev->addr_len; 655 memcpy(arp_ptr, &src_ip, 4); 656 arp_ptr += 4; 657 658 switch (dev->type) { 659 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 660 case ARPHRD_IEEE1394: 661 break; 662 #endif 663 default: 664 if (target_hw != NULL) 665 memcpy(arp_ptr, target_hw, dev->addr_len); 666 else 667 memset(arp_ptr, 0, dev->addr_len); 668 arp_ptr += dev->addr_len; 669 } 670 memcpy(arp_ptr, &dest_ip, 4); 671 672 return skb; 673 674 out: 675 kfree_skb(skb); 676 return NULL; 677 } 678 EXPORT_SYMBOL(arp_create); 679 680 /* 681 * Send an arp packet. 682 */ 683 void arp_xmit(struct sk_buff *skb) 684 { 685 /* Send it off, maybe filter it using firewalling first. */ 686 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 687 } 688 EXPORT_SYMBOL(arp_xmit); 689 690 /* 691 * Create and send an arp packet. 692 */ 693 void arp_send(int type, int ptype, __be32 dest_ip, 694 struct net_device *dev, __be32 src_ip, 695 const unsigned char *dest_hw, const unsigned char *src_hw, 696 const unsigned char *target_hw) 697 { 698 struct sk_buff *skb; 699 700 /* 701 * No arp on this interface. 702 */ 703 704 if (dev->flags&IFF_NOARP) 705 return; 706 707 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 708 dest_hw, src_hw, target_hw); 709 if (skb == NULL) 710 return; 711 712 arp_xmit(skb); 713 } 714 EXPORT_SYMBOL(arp_send); 715 716 /* 717 * Process an arp request. 718 */ 719 720 static int arp_process(struct sk_buff *skb) 721 { 722 struct net_device *dev = skb->dev; 723 struct in_device *in_dev = __in_dev_get_rcu(dev); 724 struct arphdr *arp; 725 unsigned char *arp_ptr; 726 struct rtable *rt; 727 unsigned char *sha; 728 __be32 sip, tip; 729 u16 dev_type = dev->type; 730 int addr_type; 731 struct neighbour *n; 732 struct net *net = dev_net(dev); 733 734 /* arp_rcv below verifies the ARP header and verifies the device 735 * is ARP'able. 736 */ 737 738 if (in_dev == NULL) 739 goto out; 740 741 arp = arp_hdr(skb); 742 743 switch (dev_type) { 744 default: 745 if (arp->ar_pro != htons(ETH_P_IP) || 746 htons(dev_type) != arp->ar_hrd) 747 goto out; 748 break; 749 case ARPHRD_ETHER: 750 case ARPHRD_FDDI: 751 case ARPHRD_IEEE802: 752 /* 753 * ETHERNET, and Fibre Channel (which are IEEE 802 754 * devices, according to RFC 2625) devices will accept ARP 755 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 756 * This is the case also of FDDI, where the RFC 1390 says that 757 * FDDI devices should accept ARP hardware of (1) Ethernet, 758 * however, to be more robust, we'll accept both 1 (Ethernet) 759 * or 6 (IEEE 802.2) 760 */ 761 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 762 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 763 arp->ar_pro != htons(ETH_P_IP)) 764 goto out; 765 break; 766 case ARPHRD_AX25: 767 if (arp->ar_pro != htons(AX25_P_IP) || 768 arp->ar_hrd != htons(ARPHRD_AX25)) 769 goto out; 770 break; 771 case ARPHRD_NETROM: 772 if (arp->ar_pro != htons(AX25_P_IP) || 773 arp->ar_hrd != htons(ARPHRD_NETROM)) 774 goto out; 775 break; 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 switch (dev_type) { 793 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 794 case ARPHRD_IEEE1394: 795 break; 796 #endif 797 default: 798 arp_ptr += dev->addr_len; 799 } 800 memcpy(&tip, arp_ptr, 4); 801 /* 802 * Check for bad requests for 127.x.x.x and requests for multicast 803 * addresses. If this is one such, delete it. 804 */ 805 if (ipv4_is_multicast(tip) || 806 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) 807 goto out; 808 809 /* 810 * Special case: We must set Frame Relay source Q.922 address 811 */ 812 if (dev_type == ARPHRD_DLCI) 813 sha = dev->broadcast; 814 815 /* 816 * Process entry. The idea here is we want to send a reply if it is a 817 * request for us or if it is a request for someone else that we hold 818 * a proxy for. We want to add an entry to our cache if it is a reply 819 * to us or if it is a request for our address. 820 * (The assumption for this last is that if someone is requesting our 821 * address, they are probably intending to talk to us, so it saves time 822 * if we cache their address. Their address is also probably not in 823 * our cache, since ours is not in their cache.) 824 * 825 * Putting this another way, we only care about replies if they are to 826 * us, in which case we add them to the cache. For requests, we care 827 * about those for us and those for our proxies. We reply to both, 828 * and in the case of requests for us we add the requester to the arp 829 * cache. 830 */ 831 832 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 833 if (sip == 0) { 834 if (arp->ar_op == htons(ARPOP_REQUEST) && 835 inet_addr_type(net, tip) == RTN_LOCAL && 836 !arp_ignore(in_dev, sip, tip)) 837 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, 838 dev->dev_addr, sha); 839 goto out; 840 } 841 842 if (arp->ar_op == htons(ARPOP_REQUEST) && 843 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 844 845 rt = skb_rtable(skb); 846 addr_type = rt->rt_type; 847 848 if (addr_type == RTN_LOCAL) { 849 int dont_send; 850 851 dont_send = arp_ignore(in_dev, sip, tip); 852 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 853 dont_send = arp_filter(sip, tip, dev); 854 if (!dont_send) { 855 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 856 if (n) { 857 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 858 dev, tip, sha, dev->dev_addr, 859 sha); 860 neigh_release(n); 861 } 862 } 863 goto out; 864 } else if (IN_DEV_FORWARD(in_dev)) { 865 if (addr_type == RTN_UNICAST && 866 (arp_fwd_proxy(in_dev, dev, rt) || 867 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 868 (rt->dst.dev != dev && 869 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 870 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 871 if (n) 872 neigh_release(n); 873 874 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 875 skb->pkt_type == PACKET_HOST || 876 in_dev->arp_parms->proxy_delay == 0) { 877 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 878 dev, tip, sha, dev->dev_addr, 879 sha); 880 } else { 881 pneigh_enqueue(&arp_tbl, 882 in_dev->arp_parms, skb); 883 return 0; 884 } 885 goto out; 886 } 887 } 888 } 889 890 /* Update our ARP tables */ 891 892 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 893 894 if (IN_DEV_ARP_ACCEPT(in_dev)) { 895 /* Unsolicited ARP is not accepted by default. 896 It is possible, that this option should be enabled for some 897 devices (strip is candidate) 898 */ 899 if (n == NULL && 900 (arp->ar_op == htons(ARPOP_REPLY) || 901 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) && 902 inet_addr_type(net, sip) == RTN_UNICAST) 903 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 904 } 905 906 if (n) { 907 int state = NUD_REACHABLE; 908 int override; 909 910 /* If several different ARP replies follows back-to-back, 911 use the FIRST one. It is possible, if several proxy 912 agents are active. Taking the first reply prevents 913 arp trashing and chooses the fastest router. 914 */ 915 override = time_after(jiffies, n->updated + n->parms->locktime); 916 917 /* Broadcast replies and request packets 918 do not assert neighbour reachability. 919 */ 920 if (arp->ar_op != htons(ARPOP_REPLY) || 921 skb->pkt_type != PACKET_HOST) 922 state = NUD_STALE; 923 neigh_update(n, sha, state, 924 override ? NEIGH_UPDATE_F_OVERRIDE : 0); 925 neigh_release(n); 926 } 927 928 out: 929 consume_skb(skb); 930 return 0; 931 } 932 933 static void parp_redo(struct sk_buff *skb) 934 { 935 arp_process(skb); 936 } 937 938 939 /* 940 * Receive an arp request from the device layer. 941 */ 942 943 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 944 struct packet_type *pt, struct net_device *orig_dev) 945 { 946 const struct arphdr *arp; 947 948 if (dev->flags & IFF_NOARP || 949 skb->pkt_type == PACKET_OTHERHOST || 950 skb->pkt_type == PACKET_LOOPBACK) 951 goto freeskb; 952 953 skb = skb_share_check(skb, GFP_ATOMIC); 954 if (!skb) 955 goto out_of_mem; 956 957 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 958 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 959 goto freeskb; 960 961 arp = arp_hdr(skb); 962 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 963 goto freeskb; 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 IS_ENABLED(CONFIG_FDDI) 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 int 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 int 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 (!ns_capable(net->user_ns, 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)); 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 IS_ENABLED(CONFIG_AX25) 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 IS_ENABLED(CONFIG_AX25) 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 IS_ENABLED(CONFIG_AX25) 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_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops)) 1424 return -ENOMEM; 1425 return 0; 1426 } 1427 1428 static void __net_exit arp_net_exit(struct net *net) 1429 { 1430 remove_proc_entry("arp", net->proc_net); 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