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 neigh_app_ns(neigh); 372 return; 373 } 374 } 375 376 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 377 dst_hw, dev->dev_addr, NULL); 378 } 379 380 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 381 { 382 int scope; 383 384 switch (IN_DEV_ARP_IGNORE(in_dev)) { 385 case 0: /* Reply, the tip is already validated */ 386 return 0; 387 case 1: /* Reply only if tip is configured on the incoming interface */ 388 sip = 0; 389 scope = RT_SCOPE_HOST; 390 break; 391 case 2: /* 392 * Reply only if tip is configured on the incoming interface 393 * and is in same subnet as sip 394 */ 395 scope = RT_SCOPE_HOST; 396 break; 397 case 3: /* Do not reply for scope host addresses */ 398 sip = 0; 399 scope = RT_SCOPE_LINK; 400 break; 401 case 4: /* Reserved */ 402 case 5: 403 case 6: 404 case 7: 405 return 0; 406 case 8: /* Do not reply */ 407 return 1; 408 default: 409 return 0; 410 } 411 return !inet_confirm_addr(in_dev, sip, tip, scope); 412 } 413 414 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 415 { 416 struct rtable *rt; 417 int flag = 0; 418 /*unsigned long now; */ 419 struct net *net = dev_net(dev); 420 421 rt = ip_route_output(net, sip, tip, 0, 0); 422 if (IS_ERR(rt)) 423 return 1; 424 if (rt->dst.dev != dev) { 425 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); 426 flag = 1; 427 } 428 ip_rt_put(rt); 429 return flag; 430 } 431 432 /* OBSOLETE FUNCTIONS */ 433 434 /* 435 * Find an arp mapping in the cache. If not found, post a request. 436 * 437 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 438 * even if it exists. It is supposed that skb->dev was mangled 439 * by a virtual device (eql, shaper). Nobody but broken devices 440 * is allowed to use this function, it is scheduled to be removed. --ANK 441 */ 442 443 static int arp_set_predefined(int addr_hint, unsigned char *haddr, 444 __be32 paddr, struct net_device *dev) 445 { 446 switch (addr_hint) { 447 case RTN_LOCAL: 448 pr_debug("arp called for own IP address\n"); 449 memcpy(haddr, dev->dev_addr, dev->addr_len); 450 return 1; 451 case RTN_MULTICAST: 452 arp_mc_map(paddr, haddr, dev, 1); 453 return 1; 454 case RTN_BROADCAST: 455 memcpy(haddr, dev->broadcast, dev->addr_len); 456 return 1; 457 } 458 return 0; 459 } 460 461 462 int arp_find(unsigned char *haddr, struct sk_buff *skb) 463 { 464 struct net_device *dev = skb->dev; 465 __be32 paddr; 466 struct neighbour *n; 467 468 if (!skb_dst(skb)) { 469 pr_debug("arp_find is called with dst==NULL\n"); 470 kfree_skb(skb); 471 return 1; 472 } 473 474 paddr = rt_nexthop(skb_rtable(skb), ip_hdr(skb)->daddr); 475 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, 476 paddr, dev)) 477 return 0; 478 479 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 480 481 if (n) { 482 n->used = jiffies; 483 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) { 484 neigh_ha_snapshot(haddr, n, dev); 485 neigh_release(n); 486 return 0; 487 } 488 neigh_release(n); 489 } else 490 kfree_skb(skb); 491 return 1; 492 } 493 EXPORT_SYMBOL(arp_find); 494 495 /* END OF OBSOLETE FUNCTIONS */ 496 497 /* 498 * Check if we can use proxy ARP for this path 499 */ 500 static inline int arp_fwd_proxy(struct in_device *in_dev, 501 struct net_device *dev, struct rtable *rt) 502 { 503 struct in_device *out_dev; 504 int imi, omi = -1; 505 506 if (rt->dst.dev == dev) 507 return 0; 508 509 if (!IN_DEV_PROXY_ARP(in_dev)) 510 return 0; 511 imi = IN_DEV_MEDIUM_ID(in_dev); 512 if (imi == 0) 513 return 1; 514 if (imi == -1) 515 return 0; 516 517 /* place to check for proxy_arp for routes */ 518 519 out_dev = __in_dev_get_rcu(rt->dst.dev); 520 if (out_dev) 521 omi = IN_DEV_MEDIUM_ID(out_dev); 522 523 return omi != imi && omi != -1; 524 } 525 526 /* 527 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 528 * 529 * RFC3069 supports proxy arp replies back to the same interface. This 530 * is done to support (ethernet) switch features, like RFC 3069, where 531 * the individual ports are not allowed to communicate with each 532 * other, BUT they are allowed to talk to the upstream router. As 533 * described in RFC 3069, it is possible to allow these hosts to 534 * communicate through the upstream router, by proxy_arp'ing. 535 * 536 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 537 * 538 * This technology is known by different names: 539 * In RFC 3069 it is called VLAN Aggregation. 540 * Cisco and Allied Telesyn call it Private VLAN. 541 * Hewlett-Packard call it Source-Port filtering or port-isolation. 542 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 543 * 544 */ 545 static inline int arp_fwd_pvlan(struct in_device *in_dev, 546 struct net_device *dev, struct rtable *rt, 547 __be32 sip, __be32 tip) 548 { 549 /* Private VLAN is only concerned about the same ethernet segment */ 550 if (rt->dst.dev != dev) 551 return 0; 552 553 /* Don't reply on self probes (often done by windowz boxes)*/ 554 if (sip == tip) 555 return 0; 556 557 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 558 return 1; 559 else 560 return 0; 561 } 562 563 /* 564 * Interface to link layer: send routine and receive handler. 565 */ 566 567 /* 568 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 569 * message. 570 */ 571 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 572 struct net_device *dev, __be32 src_ip, 573 const unsigned char *dest_hw, 574 const unsigned char *src_hw, 575 const unsigned char *target_hw) 576 { 577 struct sk_buff *skb; 578 struct arphdr *arp; 579 unsigned char *arp_ptr; 580 int hlen = LL_RESERVED_SPACE(dev); 581 int tlen = dev->needed_tailroom; 582 583 /* 584 * Allocate a buffer 585 */ 586 587 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 588 if (skb == NULL) 589 return NULL; 590 591 skb_reserve(skb, hlen); 592 skb_reset_network_header(skb); 593 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); 594 skb->dev = dev; 595 skb->protocol = htons(ETH_P_ARP); 596 if (src_hw == NULL) 597 src_hw = dev->dev_addr; 598 if (dest_hw == NULL) 599 dest_hw = dev->broadcast; 600 601 /* 602 * Fill the device header for the ARP frame 603 */ 604 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 605 goto out; 606 607 /* 608 * Fill out the arp protocol part. 609 * 610 * The arp hardware type should match the device type, except for FDDI, 611 * which (according to RFC 1390) should always equal 1 (Ethernet). 612 */ 613 /* 614 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 615 * DIX code for the protocol. Make these device structure fields. 616 */ 617 switch (dev->type) { 618 default: 619 arp->ar_hrd = htons(dev->type); 620 arp->ar_pro = htons(ETH_P_IP); 621 break; 622 623 #if IS_ENABLED(CONFIG_AX25) 624 case ARPHRD_AX25: 625 arp->ar_hrd = htons(ARPHRD_AX25); 626 arp->ar_pro = htons(AX25_P_IP); 627 break; 628 629 #if IS_ENABLED(CONFIG_NETROM) 630 case ARPHRD_NETROM: 631 arp->ar_hrd = htons(ARPHRD_NETROM); 632 arp->ar_pro = htons(AX25_P_IP); 633 break; 634 #endif 635 #endif 636 637 #if IS_ENABLED(CONFIG_FDDI) 638 case ARPHRD_FDDI: 639 arp->ar_hrd = htons(ARPHRD_ETHER); 640 arp->ar_pro = htons(ETH_P_IP); 641 break; 642 #endif 643 } 644 645 arp->ar_hln = dev->addr_len; 646 arp->ar_pln = 4; 647 arp->ar_op = htons(type); 648 649 arp_ptr = (unsigned char *)(arp + 1); 650 651 memcpy(arp_ptr, src_hw, dev->addr_len); 652 arp_ptr += dev->addr_len; 653 memcpy(arp_ptr, &src_ip, 4); 654 arp_ptr += 4; 655 656 switch (dev->type) { 657 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 658 case ARPHRD_IEEE1394: 659 break; 660 #endif 661 default: 662 if (target_hw != NULL) 663 memcpy(arp_ptr, target_hw, dev->addr_len); 664 else 665 memset(arp_ptr, 0, dev->addr_len); 666 arp_ptr += dev->addr_len; 667 } 668 memcpy(arp_ptr, &dest_ip, 4); 669 670 return skb; 671 672 out: 673 kfree_skb(skb); 674 return NULL; 675 } 676 EXPORT_SYMBOL(arp_create); 677 678 /* 679 * Send an arp packet. 680 */ 681 void arp_xmit(struct sk_buff *skb) 682 { 683 /* Send it off, maybe filter it using firewalling first. */ 684 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 685 } 686 EXPORT_SYMBOL(arp_xmit); 687 688 /* 689 * Create and send an arp packet. 690 */ 691 void arp_send(int type, int ptype, __be32 dest_ip, 692 struct net_device *dev, __be32 src_ip, 693 const unsigned char *dest_hw, const unsigned char *src_hw, 694 const unsigned char *target_hw) 695 { 696 struct sk_buff *skb; 697 698 /* 699 * No arp on this interface. 700 */ 701 702 if (dev->flags&IFF_NOARP) 703 return; 704 705 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 706 dest_hw, src_hw, target_hw); 707 if (skb == NULL) 708 return; 709 710 arp_xmit(skb); 711 } 712 EXPORT_SYMBOL(arp_send); 713 714 /* 715 * Process an arp request. 716 */ 717 718 static int arp_process(struct sk_buff *skb) 719 { 720 struct net_device *dev = skb->dev; 721 struct in_device *in_dev = __in_dev_get_rcu(dev); 722 struct arphdr *arp; 723 unsigned char *arp_ptr; 724 struct rtable *rt; 725 unsigned char *sha; 726 __be32 sip, tip; 727 u16 dev_type = dev->type; 728 int addr_type; 729 struct neighbour *n; 730 struct net *net = dev_net(dev); 731 732 /* arp_rcv below verifies the ARP header and verifies the device 733 * is ARP'able. 734 */ 735 736 if (in_dev == NULL) 737 goto out; 738 739 arp = arp_hdr(skb); 740 741 switch (dev_type) { 742 default: 743 if (arp->ar_pro != htons(ETH_P_IP) || 744 htons(dev_type) != arp->ar_hrd) 745 goto out; 746 break; 747 case ARPHRD_ETHER: 748 case ARPHRD_FDDI: 749 case ARPHRD_IEEE802: 750 /* 751 * ETHERNET, and Fibre Channel (which are IEEE 802 752 * devices, according to RFC 2625) devices will accept ARP 753 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 754 * This is the case also of FDDI, where the RFC 1390 says that 755 * FDDI devices should accept ARP hardware of (1) Ethernet, 756 * however, to be more robust, we'll accept both 1 (Ethernet) 757 * or 6 (IEEE 802.2) 758 */ 759 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 760 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 761 arp->ar_pro != htons(ETH_P_IP)) 762 goto out; 763 break; 764 case ARPHRD_AX25: 765 if (arp->ar_pro != htons(AX25_P_IP) || 766 arp->ar_hrd != htons(ARPHRD_AX25)) 767 goto out; 768 break; 769 case ARPHRD_NETROM: 770 if (arp->ar_pro != htons(AX25_P_IP) || 771 arp->ar_hrd != htons(ARPHRD_NETROM)) 772 goto out; 773 break; 774 } 775 776 /* Understand only these message types */ 777 778 if (arp->ar_op != htons(ARPOP_REPLY) && 779 arp->ar_op != htons(ARPOP_REQUEST)) 780 goto out; 781 782 /* 783 * Extract fields 784 */ 785 arp_ptr = (unsigned char *)(arp + 1); 786 sha = arp_ptr; 787 arp_ptr += dev->addr_len; 788 memcpy(&sip, arp_ptr, 4); 789 arp_ptr += 4; 790 switch (dev_type) { 791 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 792 case ARPHRD_IEEE1394: 793 break; 794 #endif 795 default: 796 arp_ptr += dev->addr_len; 797 } 798 memcpy(&tip, arp_ptr, 4); 799 /* 800 * Check for bad requests for 127.x.x.x and requests for multicast 801 * addresses. If this is one such, delete it. 802 */ 803 if (ipv4_is_multicast(tip) || 804 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(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 (rt->dst.dev != dev && 867 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 868 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 869 if (n) 870 neigh_release(n); 871 872 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 873 skb->pkt_type == PACKET_HOST || 874 in_dev->arp_parms->proxy_delay == 0) { 875 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 876 dev, tip, sha, dev->dev_addr, 877 sha); 878 } else { 879 pneigh_enqueue(&arp_tbl, 880 in_dev->arp_parms, skb); 881 return 0; 882 } 883 goto out; 884 } 885 } 886 } 887 888 /* Update our ARP tables */ 889 890 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 891 892 if (IN_DEV_ARP_ACCEPT(in_dev)) { 893 /* Unsolicited ARP is not accepted by default. 894 It is possible, that this option should be enabled for some 895 devices (strip is candidate) 896 */ 897 if (n == NULL && 898 (arp->ar_op == htons(ARPOP_REPLY) || 899 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) && 900 inet_addr_type(net, sip) == RTN_UNICAST) 901 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 902 } 903 904 if (n) { 905 int state = NUD_REACHABLE; 906 int override; 907 908 /* If several different ARP replies follows back-to-back, 909 use the FIRST one. It is possible, if several proxy 910 agents are active. Taking the first reply prevents 911 arp trashing and chooses the fastest router. 912 */ 913 override = time_after(jiffies, n->updated + n->parms->locktime); 914 915 /* Broadcast replies and request packets 916 do not assert neighbour reachability. 917 */ 918 if (arp->ar_op != htons(ARPOP_REPLY) || 919 skb->pkt_type != PACKET_HOST) 920 state = NUD_STALE; 921 neigh_update(n, sha, state, 922 override ? NEIGH_UPDATE_F_OVERRIDE : 0); 923 neigh_release(n); 924 } 925 926 out: 927 consume_skb(skb); 928 return 0; 929 } 930 931 static void parp_redo(struct sk_buff *skb) 932 { 933 arp_process(skb); 934 } 935 936 937 /* 938 * Receive an arp request from the device layer. 939 */ 940 941 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 942 struct packet_type *pt, struct net_device *orig_dev) 943 { 944 const struct arphdr *arp; 945 946 if (dev->flags & IFF_NOARP || 947 skb->pkt_type == PACKET_OTHERHOST || 948 skb->pkt_type == PACKET_LOOPBACK) 949 goto freeskb; 950 951 skb = skb_share_check(skb, GFP_ATOMIC); 952 if (!skb) 953 goto out_of_mem; 954 955 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 956 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 957 goto freeskb; 958 959 arp = arp_hdr(skb); 960 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 961 goto freeskb; 962 963 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 964 965 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 966 967 freeskb: 968 kfree_skb(skb); 969 out_of_mem: 970 return 0; 971 } 972 973 /* 974 * User level interface (ioctl) 975 */ 976 977 /* 978 * Set (create) an ARP cache entry. 979 */ 980 981 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 982 { 983 if (dev == NULL) { 984 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 985 return 0; 986 } 987 if (__in_dev_get_rtnl(dev)) { 988 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 989 return 0; 990 } 991 return -ENXIO; 992 } 993 994 static int arp_req_set_public(struct net *net, struct arpreq *r, 995 struct net_device *dev) 996 { 997 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 998 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 999 1000 if (mask && mask != htonl(0xFFFFFFFF)) 1001 return -EINVAL; 1002 if (!dev && (r->arp_flags & ATF_COM)) { 1003 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 1004 r->arp_ha.sa_data); 1005 if (!dev) 1006 return -ENODEV; 1007 } 1008 if (mask) { 1009 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL) 1010 return -ENOBUFS; 1011 return 0; 1012 } 1013 1014 return arp_req_set_proxy(net, dev, 1); 1015 } 1016 1017 static int arp_req_set(struct net *net, struct arpreq *r, 1018 struct net_device *dev) 1019 { 1020 __be32 ip; 1021 struct neighbour *neigh; 1022 int err; 1023 1024 if (r->arp_flags & ATF_PUBL) 1025 return arp_req_set_public(net, r, dev); 1026 1027 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1028 if (r->arp_flags & ATF_PERM) 1029 r->arp_flags |= ATF_COM; 1030 if (dev == NULL) { 1031 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1032 1033 if (IS_ERR(rt)) 1034 return PTR_ERR(rt); 1035 dev = rt->dst.dev; 1036 ip_rt_put(rt); 1037 if (!dev) 1038 return -EINVAL; 1039 } 1040 switch (dev->type) { 1041 #if IS_ENABLED(CONFIG_FDDI) 1042 case ARPHRD_FDDI: 1043 /* 1044 * According to RFC 1390, FDDI devices should accept ARP 1045 * hardware types of 1 (Ethernet). However, to be more 1046 * robust, we'll accept hardware types of either 1 (Ethernet) 1047 * or 6 (IEEE 802.2). 1048 */ 1049 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1050 r->arp_ha.sa_family != ARPHRD_ETHER && 1051 r->arp_ha.sa_family != ARPHRD_IEEE802) 1052 return -EINVAL; 1053 break; 1054 #endif 1055 default: 1056 if (r->arp_ha.sa_family != dev->type) 1057 return -EINVAL; 1058 break; 1059 } 1060 1061 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1062 err = PTR_ERR(neigh); 1063 if (!IS_ERR(neigh)) { 1064 unsigned int state = NUD_STALE; 1065 if (r->arp_flags & ATF_PERM) 1066 state = NUD_PERMANENT; 1067 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1068 r->arp_ha.sa_data : NULL, state, 1069 NEIGH_UPDATE_F_OVERRIDE | 1070 NEIGH_UPDATE_F_ADMIN); 1071 neigh_release(neigh); 1072 } 1073 return err; 1074 } 1075 1076 static unsigned int arp_state_to_flags(struct neighbour *neigh) 1077 { 1078 if (neigh->nud_state&NUD_PERMANENT) 1079 return ATF_PERM | ATF_COM; 1080 else if (neigh->nud_state&NUD_VALID) 1081 return ATF_COM; 1082 else 1083 return 0; 1084 } 1085 1086 /* 1087 * Get an ARP cache entry. 1088 */ 1089 1090 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1091 { 1092 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1093 struct neighbour *neigh; 1094 int err = -ENXIO; 1095 1096 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1097 if (neigh) { 1098 read_lock_bh(&neigh->lock); 1099 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1100 r->arp_flags = arp_state_to_flags(neigh); 1101 read_unlock_bh(&neigh->lock); 1102 r->arp_ha.sa_family = dev->type; 1103 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1104 neigh_release(neigh); 1105 err = 0; 1106 } 1107 return err; 1108 } 1109 1110 int arp_invalidate(struct net_device *dev, __be32 ip) 1111 { 1112 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1113 int err = -ENXIO; 1114 1115 if (neigh) { 1116 if (neigh->nud_state & ~NUD_NOARP) 1117 err = neigh_update(neigh, NULL, NUD_FAILED, 1118 NEIGH_UPDATE_F_OVERRIDE| 1119 NEIGH_UPDATE_F_ADMIN); 1120 neigh_release(neigh); 1121 } 1122 1123 return err; 1124 } 1125 EXPORT_SYMBOL(arp_invalidate); 1126 1127 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1128 struct net_device *dev) 1129 { 1130 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1131 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1132 1133 if (mask == htonl(0xFFFFFFFF)) 1134 return pneigh_delete(&arp_tbl, net, &ip, dev); 1135 1136 if (mask) 1137 return -EINVAL; 1138 1139 return arp_req_set_proxy(net, dev, 0); 1140 } 1141 1142 static int arp_req_delete(struct net *net, struct arpreq *r, 1143 struct net_device *dev) 1144 { 1145 __be32 ip; 1146 1147 if (r->arp_flags & ATF_PUBL) 1148 return arp_req_delete_public(net, r, dev); 1149 1150 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1151 if (dev == NULL) { 1152 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1153 if (IS_ERR(rt)) 1154 return PTR_ERR(rt); 1155 dev = rt->dst.dev; 1156 ip_rt_put(rt); 1157 if (!dev) 1158 return -EINVAL; 1159 } 1160 return arp_invalidate(dev, ip); 1161 } 1162 1163 /* 1164 * Handle an ARP layer I/O control request. 1165 */ 1166 1167 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1168 { 1169 int err; 1170 struct arpreq r; 1171 struct net_device *dev = NULL; 1172 1173 switch (cmd) { 1174 case SIOCDARP: 1175 case SIOCSARP: 1176 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1177 return -EPERM; 1178 case SIOCGARP: 1179 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1180 if (err) 1181 return -EFAULT; 1182 break; 1183 default: 1184 return -EINVAL; 1185 } 1186 1187 if (r.arp_pa.sa_family != AF_INET) 1188 return -EPFNOSUPPORT; 1189 1190 if (!(r.arp_flags & ATF_PUBL) && 1191 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1192 return -EINVAL; 1193 if (!(r.arp_flags & ATF_NETMASK)) 1194 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1195 htonl(0xFFFFFFFFUL); 1196 rtnl_lock(); 1197 if (r.arp_dev[0]) { 1198 err = -ENODEV; 1199 dev = __dev_get_by_name(net, r.arp_dev); 1200 if (dev == NULL) 1201 goto out; 1202 1203 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1204 if (!r.arp_ha.sa_family) 1205 r.arp_ha.sa_family = dev->type; 1206 err = -EINVAL; 1207 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1208 goto out; 1209 } else if (cmd == SIOCGARP) { 1210 err = -ENODEV; 1211 goto out; 1212 } 1213 1214 switch (cmd) { 1215 case SIOCDARP: 1216 err = arp_req_delete(net, &r, dev); 1217 break; 1218 case SIOCSARP: 1219 err = arp_req_set(net, &r, dev); 1220 break; 1221 case SIOCGARP: 1222 err = arp_req_get(&r, dev); 1223 break; 1224 } 1225 out: 1226 rtnl_unlock(); 1227 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1228 err = -EFAULT; 1229 return err; 1230 } 1231 1232 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1233 void *ptr) 1234 { 1235 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1236 struct netdev_notifier_change_info *change_info; 1237 1238 switch (event) { 1239 case NETDEV_CHANGEADDR: 1240 neigh_changeaddr(&arp_tbl, dev); 1241 rt_cache_flush(dev_net(dev)); 1242 break; 1243 case NETDEV_CHANGE: 1244 change_info = ptr; 1245 if (change_info->flags_changed & IFF_NOARP) 1246 neigh_changeaddr(&arp_tbl, dev); 1247 break; 1248 default: 1249 break; 1250 } 1251 1252 return NOTIFY_DONE; 1253 } 1254 1255 static struct notifier_block arp_netdev_notifier = { 1256 .notifier_call = arp_netdev_event, 1257 }; 1258 1259 /* Note, that it is not on notifier chain. 1260 It is necessary, that this routine was called after route cache will be 1261 flushed. 1262 */ 1263 void arp_ifdown(struct net_device *dev) 1264 { 1265 neigh_ifdown(&arp_tbl, dev); 1266 } 1267 1268 1269 /* 1270 * Called once on startup. 1271 */ 1272 1273 static struct packet_type arp_packet_type __read_mostly = { 1274 .type = cpu_to_be16(ETH_P_ARP), 1275 .func = arp_rcv, 1276 }; 1277 1278 static int arp_proc_init(void); 1279 1280 void __init arp_init(void) 1281 { 1282 neigh_table_init(&arp_tbl); 1283 1284 dev_add_pack(&arp_packet_type); 1285 arp_proc_init(); 1286 #ifdef CONFIG_SYSCTL 1287 neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL); 1288 #endif 1289 register_netdevice_notifier(&arp_netdev_notifier); 1290 } 1291 1292 #ifdef CONFIG_PROC_FS 1293 #if IS_ENABLED(CONFIG_AX25) 1294 1295 /* ------------------------------------------------------------------------ */ 1296 /* 1297 * ax25 -> ASCII conversion 1298 */ 1299 static char *ax2asc2(ax25_address *a, char *buf) 1300 { 1301 char c, *s; 1302 int n; 1303 1304 for (n = 0, s = buf; n < 6; n++) { 1305 c = (a->ax25_call[n] >> 1) & 0x7F; 1306 1307 if (c != ' ') 1308 *s++ = c; 1309 } 1310 1311 *s++ = '-'; 1312 n = (a->ax25_call[6] >> 1) & 0x0F; 1313 if (n > 9) { 1314 *s++ = '1'; 1315 n -= 10; 1316 } 1317 1318 *s++ = n + '0'; 1319 *s++ = '\0'; 1320 1321 if (*buf == '\0' || *buf == '-') 1322 return "*"; 1323 1324 return buf; 1325 } 1326 #endif /* CONFIG_AX25 */ 1327 1328 #define HBUFFERLEN 30 1329 1330 static void arp_format_neigh_entry(struct seq_file *seq, 1331 struct neighbour *n) 1332 { 1333 char hbuffer[HBUFFERLEN]; 1334 int k, j; 1335 char tbuf[16]; 1336 struct net_device *dev = n->dev; 1337 int hatype = dev->type; 1338 1339 read_lock(&n->lock); 1340 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1341 #if IS_ENABLED(CONFIG_AX25) 1342 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1343 ax2asc2((ax25_address *)n->ha, hbuffer); 1344 else { 1345 #endif 1346 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1347 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1348 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1349 hbuffer[k++] = ':'; 1350 } 1351 if (k != 0) 1352 --k; 1353 hbuffer[k] = 0; 1354 #if IS_ENABLED(CONFIG_AX25) 1355 } 1356 #endif 1357 sprintf(tbuf, "%pI4", n->primary_key); 1358 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1359 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1360 read_unlock(&n->lock); 1361 } 1362 1363 static void arp_format_pneigh_entry(struct seq_file *seq, 1364 struct pneigh_entry *n) 1365 { 1366 struct net_device *dev = n->dev; 1367 int hatype = dev ? dev->type : 0; 1368 char tbuf[16]; 1369 1370 sprintf(tbuf, "%pI4", n->key); 1371 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1372 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1373 dev ? dev->name : "*"); 1374 } 1375 1376 static int arp_seq_show(struct seq_file *seq, void *v) 1377 { 1378 if (v == SEQ_START_TOKEN) { 1379 seq_puts(seq, "IP address HW type Flags " 1380 "HW address Mask Device\n"); 1381 } else { 1382 struct neigh_seq_state *state = seq->private; 1383 1384 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1385 arp_format_pneigh_entry(seq, v); 1386 else 1387 arp_format_neigh_entry(seq, v); 1388 } 1389 1390 return 0; 1391 } 1392 1393 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1394 { 1395 /* Don't want to confuse "arp -a" w/ magic entries, 1396 * so we tell the generic iterator to skip NUD_NOARP. 1397 */ 1398 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1399 } 1400 1401 /* ------------------------------------------------------------------------ */ 1402 1403 static const struct seq_operations arp_seq_ops = { 1404 .start = arp_seq_start, 1405 .next = neigh_seq_next, 1406 .stop = neigh_seq_stop, 1407 .show = arp_seq_show, 1408 }; 1409 1410 static int arp_seq_open(struct inode *inode, struct file *file) 1411 { 1412 return seq_open_net(inode, file, &arp_seq_ops, 1413 sizeof(struct neigh_seq_state)); 1414 } 1415 1416 static const struct file_operations arp_seq_fops = { 1417 .owner = THIS_MODULE, 1418 .open = arp_seq_open, 1419 .read = seq_read, 1420 .llseek = seq_lseek, 1421 .release = seq_release_net, 1422 }; 1423 1424 1425 static int __net_init arp_net_init(struct net *net) 1426 { 1427 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops)) 1428 return -ENOMEM; 1429 return 0; 1430 } 1431 1432 static void __net_exit arp_net_exit(struct net *net) 1433 { 1434 remove_proc_entry("arp", net->proc_net); 1435 } 1436 1437 static struct pernet_operations arp_net_ops = { 1438 .init = arp_net_init, 1439 .exit = arp_net_exit, 1440 }; 1441 1442 static int __init arp_proc_init(void) 1443 { 1444 return register_pernet_subsys(&arp_net_ops); 1445 } 1446 1447 #else /* CONFIG_PROC_FS */ 1448 1449 static int __init arp_proc_init(void) 1450 { 1451 return 0; 1452 } 1453 1454 #endif /* CONFIG_PROC_FS */ 1455