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 .reachable_time = 30 * HZ, 170 .data = { 171 [NEIGH_VAR_MCAST_PROBES] = 3, 172 [NEIGH_VAR_UCAST_PROBES] = 3, 173 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ, 174 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ, 175 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ, 176 [NEIGH_VAR_GC_STALETIME] = 60 * HZ, 177 [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024, 178 [NEIGH_VAR_PROXY_QLEN] = 64, 179 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ, 180 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10, 181 [NEIGH_VAR_LOCKTIME] = 1 * HZ, 182 }, 183 }, 184 .gc_interval = 30 * HZ, 185 .gc_thresh1 = 128, 186 .gc_thresh2 = 512, 187 .gc_thresh3 = 1024, 188 }; 189 EXPORT_SYMBOL(arp_tbl); 190 191 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 192 { 193 switch (dev->type) { 194 case ARPHRD_ETHER: 195 case ARPHRD_FDDI: 196 case ARPHRD_IEEE802: 197 ip_eth_mc_map(addr, haddr); 198 return 0; 199 case ARPHRD_INFINIBAND: 200 ip_ib_mc_map(addr, dev->broadcast, haddr); 201 return 0; 202 case ARPHRD_IPGRE: 203 ip_ipgre_mc_map(addr, dev->broadcast, haddr); 204 return 0; 205 default: 206 if (dir) { 207 memcpy(haddr, dev->broadcast, dev->addr_len); 208 return 0; 209 } 210 } 211 return -EINVAL; 212 } 213 214 215 static u32 arp_hash(const void *pkey, 216 const struct net_device *dev, 217 __u32 *hash_rnd) 218 { 219 return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd); 220 } 221 222 static int arp_constructor(struct neighbour *neigh) 223 { 224 __be32 addr = *(__be32 *)neigh->primary_key; 225 struct net_device *dev = neigh->dev; 226 struct in_device *in_dev; 227 struct neigh_parms *parms; 228 229 rcu_read_lock(); 230 in_dev = __in_dev_get_rcu(dev); 231 if (in_dev == NULL) { 232 rcu_read_unlock(); 233 return -EINVAL; 234 } 235 236 neigh->type = inet_addr_type(dev_net(dev), addr); 237 238 parms = in_dev->arp_parms; 239 __neigh_parms_put(neigh->parms); 240 neigh->parms = neigh_parms_clone(parms); 241 rcu_read_unlock(); 242 243 if (!dev->header_ops) { 244 neigh->nud_state = NUD_NOARP; 245 neigh->ops = &arp_direct_ops; 246 neigh->output = neigh_direct_output; 247 } else { 248 /* Good devices (checked by reading texts, but only Ethernet is 249 tested) 250 251 ARPHRD_ETHER: (ethernet, apfddi) 252 ARPHRD_FDDI: (fddi) 253 ARPHRD_IEEE802: (tr) 254 ARPHRD_METRICOM: (strip) 255 ARPHRD_ARCNET: 256 etc. etc. etc. 257 258 ARPHRD_IPDDP will also work, if author repairs it. 259 I did not it, because this driver does not work even 260 in old paradigm. 261 */ 262 263 #if 1 264 /* So... these "amateur" devices are hopeless. 265 The only thing, that I can say now: 266 It is very sad that we need to keep ugly obsolete 267 code to make them happy. 268 269 They should be moved to more reasonable state, now 270 they use rebuild_header INSTEAD OF hard_start_xmit!!! 271 Besides that, they are sort of out of date 272 (a lot of redundant clones/copies, useless in 2.1), 273 I wonder why people believe that they work. 274 */ 275 switch (dev->type) { 276 default: 277 break; 278 case ARPHRD_ROSE: 279 #if IS_ENABLED(CONFIG_AX25) 280 case ARPHRD_AX25: 281 #if IS_ENABLED(CONFIG_NETROM) 282 case ARPHRD_NETROM: 283 #endif 284 neigh->ops = &arp_broken_ops; 285 neigh->output = neigh->ops->output; 286 return 0; 287 #else 288 break; 289 #endif 290 } 291 #endif 292 if (neigh->type == RTN_MULTICAST) { 293 neigh->nud_state = NUD_NOARP; 294 arp_mc_map(addr, neigh->ha, dev, 1); 295 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 296 neigh->nud_state = NUD_NOARP; 297 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 298 } else if (neigh->type == RTN_BROADCAST || 299 (dev->flags & IFF_POINTOPOINT)) { 300 neigh->nud_state = NUD_NOARP; 301 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 302 } 303 304 if (dev->header_ops->cache) 305 neigh->ops = &arp_hh_ops; 306 else 307 neigh->ops = &arp_generic_ops; 308 309 if (neigh->nud_state & NUD_VALID) 310 neigh->output = neigh->ops->connected_output; 311 else 312 neigh->output = neigh->ops->output; 313 } 314 return 0; 315 } 316 317 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 318 { 319 dst_link_failure(skb); 320 kfree_skb(skb); 321 } 322 323 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 324 { 325 __be32 saddr = 0; 326 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL; 327 struct net_device *dev = neigh->dev; 328 __be32 target = *(__be32 *)neigh->primary_key; 329 int probes = atomic_read(&neigh->probes); 330 struct in_device *in_dev; 331 332 rcu_read_lock(); 333 in_dev = __in_dev_get_rcu(dev); 334 if (!in_dev) { 335 rcu_read_unlock(); 336 return; 337 } 338 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 339 default: 340 case 0: /* By default announce any local IP */ 341 if (skb && inet_addr_type(dev_net(dev), 342 ip_hdr(skb)->saddr) == RTN_LOCAL) 343 saddr = ip_hdr(skb)->saddr; 344 break; 345 case 1: /* Restrict announcements of saddr in same subnet */ 346 if (!skb) 347 break; 348 saddr = ip_hdr(skb)->saddr; 349 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { 350 /* saddr should be known to target */ 351 if (inet_addr_onlink(in_dev, target, saddr)) 352 break; 353 } 354 saddr = 0; 355 break; 356 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 357 break; 358 } 359 rcu_read_unlock(); 360 361 if (!saddr) 362 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 363 364 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); 365 if (probes < 0) { 366 if (!(neigh->nud_state & NUD_VALID)) 367 pr_debug("trying to ucast probe in NUD_INVALID\n"); 368 neigh_ha_snapshot(dst_ha, neigh, dev); 369 dst_hw = dst_ha; 370 } else { 371 probes -= NEIGH_VAR(neigh->parms, APP_PROBES); 372 if (probes < 0) { 373 neigh_app_ns(neigh); 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 struct net *net = dev_net(in_dev->dev); 385 int scope; 386 387 switch (IN_DEV_ARP_IGNORE(in_dev)) { 388 case 0: /* Reply, the tip is already validated */ 389 return 0; 390 case 1: /* Reply only if tip is configured on the incoming interface */ 391 sip = 0; 392 scope = RT_SCOPE_HOST; 393 break; 394 case 2: /* 395 * Reply only if tip is configured on the incoming interface 396 * and is in same subnet as sip 397 */ 398 scope = RT_SCOPE_HOST; 399 break; 400 case 3: /* Do not reply for scope host addresses */ 401 sip = 0; 402 scope = RT_SCOPE_LINK; 403 in_dev = NULL; 404 break; 405 case 4: /* Reserved */ 406 case 5: 407 case 6: 408 case 7: 409 return 0; 410 case 8: /* Do not reply */ 411 return 1; 412 default: 413 return 0; 414 } 415 return !inet_confirm_addr(net, in_dev, sip, tip, scope); 416 } 417 418 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 419 { 420 struct rtable *rt; 421 int flag = 0; 422 /*unsigned long now; */ 423 struct net *net = dev_net(dev); 424 425 rt = ip_route_output(net, sip, tip, 0, 0); 426 if (IS_ERR(rt)) 427 return 1; 428 if (rt->dst.dev != dev) { 429 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); 430 flag = 1; 431 } 432 ip_rt_put(rt); 433 return flag; 434 } 435 436 /* OBSOLETE FUNCTIONS */ 437 438 /* 439 * Find an arp mapping in the cache. If not found, post a request. 440 * 441 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour, 442 * even if it exists. It is supposed that skb->dev was mangled 443 * by a virtual device (eql, shaper). Nobody but broken devices 444 * is allowed to use this function, it is scheduled to be removed. --ANK 445 */ 446 447 static int arp_set_predefined(int addr_hint, unsigned char *haddr, 448 __be32 paddr, struct net_device *dev) 449 { 450 switch (addr_hint) { 451 case RTN_LOCAL: 452 pr_debug("arp called for own IP address\n"); 453 memcpy(haddr, dev->dev_addr, dev->addr_len); 454 return 1; 455 case RTN_MULTICAST: 456 arp_mc_map(paddr, haddr, dev, 1); 457 return 1; 458 case RTN_BROADCAST: 459 memcpy(haddr, dev->broadcast, dev->addr_len); 460 return 1; 461 } 462 return 0; 463 } 464 465 466 int arp_find(unsigned char *haddr, struct sk_buff *skb) 467 { 468 struct net_device *dev = skb->dev; 469 __be32 paddr; 470 struct neighbour *n; 471 472 if (!skb_dst(skb)) { 473 pr_debug("arp_find is called with dst==NULL\n"); 474 kfree_skb(skb); 475 return 1; 476 } 477 478 paddr = rt_nexthop(skb_rtable(skb), ip_hdr(skb)->daddr); 479 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, 480 paddr, dev)) 481 return 0; 482 483 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); 484 485 if (n) { 486 n->used = jiffies; 487 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) { 488 neigh_ha_snapshot(haddr, n, dev); 489 neigh_release(n); 490 return 0; 491 } 492 neigh_release(n); 493 } else 494 kfree_skb(skb); 495 return 1; 496 } 497 EXPORT_SYMBOL(arp_find); 498 499 /* END OF OBSOLETE FUNCTIONS */ 500 501 /* 502 * Check if we can use proxy ARP for this path 503 */ 504 static inline int arp_fwd_proxy(struct in_device *in_dev, 505 struct net_device *dev, struct rtable *rt) 506 { 507 struct in_device *out_dev; 508 int imi, omi = -1; 509 510 if (rt->dst.dev == dev) 511 return 0; 512 513 if (!IN_DEV_PROXY_ARP(in_dev)) 514 return 0; 515 imi = IN_DEV_MEDIUM_ID(in_dev); 516 if (imi == 0) 517 return 1; 518 if (imi == -1) 519 return 0; 520 521 /* place to check for proxy_arp for routes */ 522 523 out_dev = __in_dev_get_rcu(rt->dst.dev); 524 if (out_dev) 525 omi = IN_DEV_MEDIUM_ID(out_dev); 526 527 return omi != imi && omi != -1; 528 } 529 530 /* 531 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 532 * 533 * RFC3069 supports proxy arp replies back to the same interface. This 534 * is done to support (ethernet) switch features, like RFC 3069, where 535 * the individual ports are not allowed to communicate with each 536 * other, BUT they are allowed to talk to the upstream router. As 537 * described in RFC 3069, it is possible to allow these hosts to 538 * communicate through the upstream router, by proxy_arp'ing. 539 * 540 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 541 * 542 * This technology is known by different names: 543 * In RFC 3069 it is called VLAN Aggregation. 544 * Cisco and Allied Telesyn call it Private VLAN. 545 * Hewlett-Packard call it Source-Port filtering or port-isolation. 546 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 547 * 548 */ 549 static inline int arp_fwd_pvlan(struct in_device *in_dev, 550 struct net_device *dev, struct rtable *rt, 551 __be32 sip, __be32 tip) 552 { 553 /* Private VLAN is only concerned about the same ethernet segment */ 554 if (rt->dst.dev != dev) 555 return 0; 556 557 /* Don't reply on self probes (often done by windowz boxes)*/ 558 if (sip == tip) 559 return 0; 560 561 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 562 return 1; 563 else 564 return 0; 565 } 566 567 /* 568 * Interface to link layer: send routine and receive handler. 569 */ 570 571 /* 572 * Create an arp packet. If (dest_hw == NULL), we create a broadcast 573 * message. 574 */ 575 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 576 struct net_device *dev, __be32 src_ip, 577 const unsigned char *dest_hw, 578 const unsigned char *src_hw, 579 const unsigned char *target_hw) 580 { 581 struct sk_buff *skb; 582 struct arphdr *arp; 583 unsigned char *arp_ptr; 584 int hlen = LL_RESERVED_SPACE(dev); 585 int tlen = dev->needed_tailroom; 586 587 /* 588 * Allocate a buffer 589 */ 590 591 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 592 if (skb == NULL) 593 return NULL; 594 595 skb_reserve(skb, hlen); 596 skb_reset_network_header(skb); 597 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); 598 skb->dev = dev; 599 skb->protocol = htons(ETH_P_ARP); 600 if (src_hw == NULL) 601 src_hw = dev->dev_addr; 602 if (dest_hw == NULL) 603 dest_hw = dev->broadcast; 604 605 /* 606 * Fill the device header for the ARP frame 607 */ 608 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 609 goto out; 610 611 /* 612 * Fill out the arp protocol part. 613 * 614 * The arp hardware type should match the device type, except for FDDI, 615 * which (according to RFC 1390) should always equal 1 (Ethernet). 616 */ 617 /* 618 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 619 * DIX code for the protocol. Make these device structure fields. 620 */ 621 switch (dev->type) { 622 default: 623 arp->ar_hrd = htons(dev->type); 624 arp->ar_pro = htons(ETH_P_IP); 625 break; 626 627 #if IS_ENABLED(CONFIG_AX25) 628 case ARPHRD_AX25: 629 arp->ar_hrd = htons(ARPHRD_AX25); 630 arp->ar_pro = htons(AX25_P_IP); 631 break; 632 633 #if IS_ENABLED(CONFIG_NETROM) 634 case ARPHRD_NETROM: 635 arp->ar_hrd = htons(ARPHRD_NETROM); 636 arp->ar_pro = htons(AX25_P_IP); 637 break; 638 #endif 639 #endif 640 641 #if IS_ENABLED(CONFIG_FDDI) 642 case ARPHRD_FDDI: 643 arp->ar_hrd = htons(ARPHRD_ETHER); 644 arp->ar_pro = htons(ETH_P_IP); 645 break; 646 #endif 647 } 648 649 arp->ar_hln = dev->addr_len; 650 arp->ar_pln = 4; 651 arp->ar_op = htons(type); 652 653 arp_ptr = (unsigned char *)(arp + 1); 654 655 memcpy(arp_ptr, src_hw, dev->addr_len); 656 arp_ptr += dev->addr_len; 657 memcpy(arp_ptr, &src_ip, 4); 658 arp_ptr += 4; 659 660 switch (dev->type) { 661 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 662 case ARPHRD_IEEE1394: 663 break; 664 #endif 665 default: 666 if (target_hw != NULL) 667 memcpy(arp_ptr, target_hw, dev->addr_len); 668 else 669 memset(arp_ptr, 0, dev->addr_len); 670 arp_ptr += dev->addr_len; 671 } 672 memcpy(arp_ptr, &dest_ip, 4); 673 674 return skb; 675 676 out: 677 kfree_skb(skb); 678 return NULL; 679 } 680 EXPORT_SYMBOL(arp_create); 681 682 /* 683 * Send an arp packet. 684 */ 685 void arp_xmit(struct sk_buff *skb) 686 { 687 /* Send it off, maybe filter it using firewalling first. */ 688 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); 689 } 690 EXPORT_SYMBOL(arp_xmit); 691 692 /* 693 * Create and send an arp packet. 694 */ 695 void arp_send(int type, int ptype, __be32 dest_ip, 696 struct net_device *dev, __be32 src_ip, 697 const unsigned char *dest_hw, const unsigned char *src_hw, 698 const unsigned char *target_hw) 699 { 700 struct sk_buff *skb; 701 702 /* 703 * No arp on this interface. 704 */ 705 706 if (dev->flags&IFF_NOARP) 707 return; 708 709 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 710 dest_hw, src_hw, target_hw); 711 if (skb == NULL) 712 return; 713 714 arp_xmit(skb); 715 } 716 EXPORT_SYMBOL(arp_send); 717 718 /* 719 * Process an arp request. 720 */ 721 722 static int arp_process(struct sk_buff *skb) 723 { 724 struct net_device *dev = skb->dev; 725 struct in_device *in_dev = __in_dev_get_rcu(dev); 726 struct arphdr *arp; 727 unsigned char *arp_ptr; 728 struct rtable *rt; 729 unsigned char *sha; 730 __be32 sip, tip; 731 u16 dev_type = dev->type; 732 int addr_type; 733 struct neighbour *n; 734 struct net *net = dev_net(dev); 735 736 /* arp_rcv below verifies the ARP header and verifies the device 737 * is ARP'able. 738 */ 739 740 if (in_dev == NULL) 741 goto out; 742 743 arp = arp_hdr(skb); 744 745 switch (dev_type) { 746 default: 747 if (arp->ar_pro != htons(ETH_P_IP) || 748 htons(dev_type) != arp->ar_hrd) 749 goto out; 750 break; 751 case ARPHRD_ETHER: 752 case ARPHRD_FDDI: 753 case ARPHRD_IEEE802: 754 /* 755 * ETHERNET, and Fibre Channel (which are IEEE 802 756 * devices, according to RFC 2625) devices will accept ARP 757 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 758 * This is the case also of FDDI, where the RFC 1390 says that 759 * FDDI devices should accept ARP hardware of (1) Ethernet, 760 * however, to be more robust, we'll accept both 1 (Ethernet) 761 * or 6 (IEEE 802.2) 762 */ 763 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 764 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 765 arp->ar_pro != htons(ETH_P_IP)) 766 goto out; 767 break; 768 case ARPHRD_AX25: 769 if (arp->ar_pro != htons(AX25_P_IP) || 770 arp->ar_hrd != htons(ARPHRD_AX25)) 771 goto out; 772 break; 773 case ARPHRD_NETROM: 774 if (arp->ar_pro != htons(AX25_P_IP) || 775 arp->ar_hrd != htons(ARPHRD_NETROM)) 776 goto out; 777 break; 778 } 779 780 /* Understand only these message types */ 781 782 if (arp->ar_op != htons(ARPOP_REPLY) && 783 arp->ar_op != htons(ARPOP_REQUEST)) 784 goto out; 785 786 /* 787 * Extract fields 788 */ 789 arp_ptr = (unsigned char *)(arp + 1); 790 sha = arp_ptr; 791 arp_ptr += dev->addr_len; 792 memcpy(&sip, arp_ptr, 4); 793 arp_ptr += 4; 794 switch (dev_type) { 795 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 796 case ARPHRD_IEEE1394: 797 break; 798 #endif 799 default: 800 arp_ptr += dev->addr_len; 801 } 802 memcpy(&tip, arp_ptr, 4); 803 /* 804 * Check for bad requests for 127.x.x.x and requests for multicast 805 * addresses. If this is one such, delete it. 806 */ 807 if (ipv4_is_multicast(tip) || 808 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) 809 goto out; 810 811 /* 812 * Special case: We must set Frame Relay source Q.922 address 813 */ 814 if (dev_type == ARPHRD_DLCI) 815 sha = dev->broadcast; 816 817 /* 818 * Process entry. The idea here is we want to send a reply if it is a 819 * request for us or if it is a request for someone else that we hold 820 * a proxy for. We want to add an entry to our cache if it is a reply 821 * to us or if it is a request for our address. 822 * (The assumption for this last is that if someone is requesting our 823 * address, they are probably intending to talk to us, so it saves time 824 * if we cache their address. Their address is also probably not in 825 * our cache, since ours is not in their cache.) 826 * 827 * Putting this another way, we only care about replies if they are to 828 * us, in which case we add them to the cache. For requests, we care 829 * about those for us and those for our proxies. We reply to both, 830 * and in the case of requests for us we add the requester to the arp 831 * cache. 832 */ 833 834 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 835 if (sip == 0) { 836 if (arp->ar_op == htons(ARPOP_REQUEST) && 837 inet_addr_type(net, tip) == RTN_LOCAL && 838 !arp_ignore(in_dev, sip, tip)) 839 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, 840 dev->dev_addr, sha); 841 goto out; 842 } 843 844 if (arp->ar_op == htons(ARPOP_REQUEST) && 845 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 846 847 rt = skb_rtable(skb); 848 addr_type = rt->rt_type; 849 850 if (addr_type == RTN_LOCAL) { 851 int dont_send; 852 853 dont_send = arp_ignore(in_dev, sip, tip); 854 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 855 dont_send = arp_filter(sip, tip, dev); 856 if (!dont_send) { 857 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 858 if (n) { 859 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 860 dev, tip, sha, dev->dev_addr, 861 sha); 862 neigh_release(n); 863 } 864 } 865 goto out; 866 } else if (IN_DEV_FORWARD(in_dev)) { 867 if (addr_type == RTN_UNICAST && 868 (arp_fwd_proxy(in_dev, dev, rt) || 869 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 870 (rt->dst.dev != dev && 871 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 872 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 873 if (n) 874 neigh_release(n); 875 876 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 877 skb->pkt_type == PACKET_HOST || 878 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { 879 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 880 dev, tip, sha, dev->dev_addr, 881 sha); 882 } else { 883 pneigh_enqueue(&arp_tbl, 884 in_dev->arp_parms, skb); 885 return 0; 886 } 887 goto out; 888 } 889 } 890 } 891 892 /* Update our ARP tables */ 893 894 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 895 896 if (IN_DEV_ARP_ACCEPT(in_dev)) { 897 /* Unsolicited ARP is not accepted by default. 898 It is possible, that this option should be enabled for some 899 devices (strip is candidate) 900 */ 901 if (n == NULL && 902 (arp->ar_op == htons(ARPOP_REPLY) || 903 (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) && 904 inet_addr_type(net, sip) == RTN_UNICAST) 905 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 906 } 907 908 if (n) { 909 int state = NUD_REACHABLE; 910 int override; 911 912 /* If several different ARP replies follows back-to-back, 913 use the FIRST one. It is possible, if several proxy 914 agents are active. Taking the first reply prevents 915 arp trashing and chooses the fastest router. 916 */ 917 override = time_after(jiffies, n->updated + 918 NEIGH_VAR(n->parms, LOCKTIME)); 919 920 /* Broadcast replies and request packets 921 do not assert neighbour reachability. 922 */ 923 if (arp->ar_op != htons(ARPOP_REPLY) || 924 skb->pkt_type != PACKET_HOST) 925 state = NUD_STALE; 926 neigh_update(n, sha, state, 927 override ? NEIGH_UPDATE_F_OVERRIDE : 0); 928 neigh_release(n); 929 } 930 931 out: 932 consume_skb(skb); 933 return 0; 934 } 935 936 static void parp_redo(struct sk_buff *skb) 937 { 938 arp_process(skb); 939 } 940 941 942 /* 943 * Receive an arp request from the device layer. 944 */ 945 946 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 947 struct packet_type *pt, struct net_device *orig_dev) 948 { 949 const struct arphdr *arp; 950 951 if (dev->flags & IFF_NOARP || 952 skb->pkt_type == PACKET_OTHERHOST || 953 skb->pkt_type == PACKET_LOOPBACK) 954 goto freeskb; 955 956 skb = skb_share_check(skb, GFP_ATOMIC); 957 if (!skb) 958 goto out_of_mem; 959 960 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 961 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 962 goto freeskb; 963 964 arp = arp_hdr(skb); 965 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 966 goto freeskb; 967 968 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 969 970 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 971 972 freeskb: 973 kfree_skb(skb); 974 out_of_mem: 975 return 0; 976 } 977 978 /* 979 * User level interface (ioctl) 980 */ 981 982 /* 983 * Set (create) an ARP cache entry. 984 */ 985 986 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 987 { 988 if (dev == NULL) { 989 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 990 return 0; 991 } 992 if (__in_dev_get_rtnl(dev)) { 993 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 994 return 0; 995 } 996 return -ENXIO; 997 } 998 999 static int arp_req_set_public(struct net *net, struct arpreq *r, 1000 struct net_device *dev) 1001 { 1002 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1003 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1004 1005 if (mask && mask != htonl(0xFFFFFFFF)) 1006 return -EINVAL; 1007 if (!dev && (r->arp_flags & ATF_COM)) { 1008 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 1009 r->arp_ha.sa_data); 1010 if (!dev) 1011 return -ENODEV; 1012 } 1013 if (mask) { 1014 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL) 1015 return -ENOBUFS; 1016 return 0; 1017 } 1018 1019 return arp_req_set_proxy(net, dev, 1); 1020 } 1021 1022 static int arp_req_set(struct net *net, struct arpreq *r, 1023 struct net_device *dev) 1024 { 1025 __be32 ip; 1026 struct neighbour *neigh; 1027 int err; 1028 1029 if (r->arp_flags & ATF_PUBL) 1030 return arp_req_set_public(net, r, dev); 1031 1032 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1033 if (r->arp_flags & ATF_PERM) 1034 r->arp_flags |= ATF_COM; 1035 if (dev == NULL) { 1036 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1037 1038 if (IS_ERR(rt)) 1039 return PTR_ERR(rt); 1040 dev = rt->dst.dev; 1041 ip_rt_put(rt); 1042 if (!dev) 1043 return -EINVAL; 1044 } 1045 switch (dev->type) { 1046 #if IS_ENABLED(CONFIG_FDDI) 1047 case ARPHRD_FDDI: 1048 /* 1049 * According to RFC 1390, FDDI devices should accept ARP 1050 * hardware types of 1 (Ethernet). However, to be more 1051 * robust, we'll accept hardware types of either 1 (Ethernet) 1052 * or 6 (IEEE 802.2). 1053 */ 1054 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1055 r->arp_ha.sa_family != ARPHRD_ETHER && 1056 r->arp_ha.sa_family != ARPHRD_IEEE802) 1057 return -EINVAL; 1058 break; 1059 #endif 1060 default: 1061 if (r->arp_ha.sa_family != dev->type) 1062 return -EINVAL; 1063 break; 1064 } 1065 1066 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1067 err = PTR_ERR(neigh); 1068 if (!IS_ERR(neigh)) { 1069 unsigned int state = NUD_STALE; 1070 if (r->arp_flags & ATF_PERM) 1071 state = NUD_PERMANENT; 1072 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1073 r->arp_ha.sa_data : NULL, state, 1074 NEIGH_UPDATE_F_OVERRIDE | 1075 NEIGH_UPDATE_F_ADMIN); 1076 neigh_release(neigh); 1077 } 1078 return err; 1079 } 1080 1081 static unsigned int arp_state_to_flags(struct neighbour *neigh) 1082 { 1083 if (neigh->nud_state&NUD_PERMANENT) 1084 return ATF_PERM | ATF_COM; 1085 else if (neigh->nud_state&NUD_VALID) 1086 return ATF_COM; 1087 else 1088 return 0; 1089 } 1090 1091 /* 1092 * Get an ARP cache entry. 1093 */ 1094 1095 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1096 { 1097 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1098 struct neighbour *neigh; 1099 int err = -ENXIO; 1100 1101 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1102 if (neigh) { 1103 read_lock_bh(&neigh->lock); 1104 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1105 r->arp_flags = arp_state_to_flags(neigh); 1106 read_unlock_bh(&neigh->lock); 1107 r->arp_ha.sa_family = dev->type; 1108 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1109 neigh_release(neigh); 1110 err = 0; 1111 } 1112 return err; 1113 } 1114 1115 static int arp_invalidate(struct net_device *dev, __be32 ip) 1116 { 1117 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1118 int err = -ENXIO; 1119 1120 if (neigh) { 1121 if (neigh->nud_state & ~NUD_NOARP) 1122 err = neigh_update(neigh, NULL, NUD_FAILED, 1123 NEIGH_UPDATE_F_OVERRIDE| 1124 NEIGH_UPDATE_F_ADMIN); 1125 neigh_release(neigh); 1126 } 1127 1128 return err; 1129 } 1130 1131 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1132 struct net_device *dev) 1133 { 1134 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1135 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1136 1137 if (mask == htonl(0xFFFFFFFF)) 1138 return pneigh_delete(&arp_tbl, net, &ip, dev); 1139 1140 if (mask) 1141 return -EINVAL; 1142 1143 return arp_req_set_proxy(net, dev, 0); 1144 } 1145 1146 static int arp_req_delete(struct net *net, struct arpreq *r, 1147 struct net_device *dev) 1148 { 1149 __be32 ip; 1150 1151 if (r->arp_flags & ATF_PUBL) 1152 return arp_req_delete_public(net, r, dev); 1153 1154 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1155 if (dev == NULL) { 1156 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1157 if (IS_ERR(rt)) 1158 return PTR_ERR(rt); 1159 dev = rt->dst.dev; 1160 ip_rt_put(rt); 1161 if (!dev) 1162 return -EINVAL; 1163 } 1164 return arp_invalidate(dev, ip); 1165 } 1166 1167 /* 1168 * Handle an ARP layer I/O control request. 1169 */ 1170 1171 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1172 { 1173 int err; 1174 struct arpreq r; 1175 struct net_device *dev = NULL; 1176 1177 switch (cmd) { 1178 case SIOCDARP: 1179 case SIOCSARP: 1180 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1181 return -EPERM; 1182 case SIOCGARP: 1183 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1184 if (err) 1185 return -EFAULT; 1186 break; 1187 default: 1188 return -EINVAL; 1189 } 1190 1191 if (r.arp_pa.sa_family != AF_INET) 1192 return -EPFNOSUPPORT; 1193 1194 if (!(r.arp_flags & ATF_PUBL) && 1195 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1196 return -EINVAL; 1197 if (!(r.arp_flags & ATF_NETMASK)) 1198 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1199 htonl(0xFFFFFFFFUL); 1200 rtnl_lock(); 1201 if (r.arp_dev[0]) { 1202 err = -ENODEV; 1203 dev = __dev_get_by_name(net, r.arp_dev); 1204 if (dev == NULL) 1205 goto out; 1206 1207 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1208 if (!r.arp_ha.sa_family) 1209 r.arp_ha.sa_family = dev->type; 1210 err = -EINVAL; 1211 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1212 goto out; 1213 } else if (cmd == SIOCGARP) { 1214 err = -ENODEV; 1215 goto out; 1216 } 1217 1218 switch (cmd) { 1219 case SIOCDARP: 1220 err = arp_req_delete(net, &r, dev); 1221 break; 1222 case SIOCSARP: 1223 err = arp_req_set(net, &r, dev); 1224 break; 1225 case SIOCGARP: 1226 err = arp_req_get(&r, dev); 1227 break; 1228 } 1229 out: 1230 rtnl_unlock(); 1231 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1232 err = -EFAULT; 1233 return err; 1234 } 1235 1236 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1237 void *ptr) 1238 { 1239 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1240 struct netdev_notifier_change_info *change_info; 1241 1242 switch (event) { 1243 case NETDEV_CHANGEADDR: 1244 neigh_changeaddr(&arp_tbl, dev); 1245 rt_cache_flush(dev_net(dev)); 1246 break; 1247 case NETDEV_CHANGE: 1248 change_info = ptr; 1249 if (change_info->flags_changed & IFF_NOARP) 1250 neigh_changeaddr(&arp_tbl, dev); 1251 break; 1252 default: 1253 break; 1254 } 1255 1256 return NOTIFY_DONE; 1257 } 1258 1259 static struct notifier_block arp_netdev_notifier = { 1260 .notifier_call = arp_netdev_event, 1261 }; 1262 1263 /* Note, that it is not on notifier chain. 1264 It is necessary, that this routine was called after route cache will be 1265 flushed. 1266 */ 1267 void arp_ifdown(struct net_device *dev) 1268 { 1269 neigh_ifdown(&arp_tbl, dev); 1270 } 1271 1272 1273 /* 1274 * Called once on startup. 1275 */ 1276 1277 static struct packet_type arp_packet_type __read_mostly = { 1278 .type = cpu_to_be16(ETH_P_ARP), 1279 .func = arp_rcv, 1280 }; 1281 1282 static int arp_proc_init(void); 1283 1284 void __init arp_init(void) 1285 { 1286 neigh_table_init(&arp_tbl); 1287 1288 dev_add_pack(&arp_packet_type); 1289 arp_proc_init(); 1290 #ifdef CONFIG_SYSCTL 1291 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL); 1292 #endif 1293 register_netdevice_notifier(&arp_netdev_notifier); 1294 } 1295 1296 #ifdef CONFIG_PROC_FS 1297 #if IS_ENABLED(CONFIG_AX25) 1298 1299 /* ------------------------------------------------------------------------ */ 1300 /* 1301 * ax25 -> ASCII conversion 1302 */ 1303 static char *ax2asc2(ax25_address *a, char *buf) 1304 { 1305 char c, *s; 1306 int n; 1307 1308 for (n = 0, s = buf; n < 6; n++) { 1309 c = (a->ax25_call[n] >> 1) & 0x7F; 1310 1311 if (c != ' ') 1312 *s++ = c; 1313 } 1314 1315 *s++ = '-'; 1316 n = (a->ax25_call[6] >> 1) & 0x0F; 1317 if (n > 9) { 1318 *s++ = '1'; 1319 n -= 10; 1320 } 1321 1322 *s++ = n + '0'; 1323 *s++ = '\0'; 1324 1325 if (*buf == '\0' || *buf == '-') 1326 return "*"; 1327 1328 return buf; 1329 } 1330 #endif /* CONFIG_AX25 */ 1331 1332 #define HBUFFERLEN 30 1333 1334 static void arp_format_neigh_entry(struct seq_file *seq, 1335 struct neighbour *n) 1336 { 1337 char hbuffer[HBUFFERLEN]; 1338 int k, j; 1339 char tbuf[16]; 1340 struct net_device *dev = n->dev; 1341 int hatype = dev->type; 1342 1343 read_lock(&n->lock); 1344 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1345 #if IS_ENABLED(CONFIG_AX25) 1346 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1347 ax2asc2((ax25_address *)n->ha, hbuffer); 1348 else { 1349 #endif 1350 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1351 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1352 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1353 hbuffer[k++] = ':'; 1354 } 1355 if (k != 0) 1356 --k; 1357 hbuffer[k] = 0; 1358 #if IS_ENABLED(CONFIG_AX25) 1359 } 1360 #endif 1361 sprintf(tbuf, "%pI4", n->primary_key); 1362 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1363 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1364 read_unlock(&n->lock); 1365 } 1366 1367 static void arp_format_pneigh_entry(struct seq_file *seq, 1368 struct pneigh_entry *n) 1369 { 1370 struct net_device *dev = n->dev; 1371 int hatype = dev ? dev->type : 0; 1372 char tbuf[16]; 1373 1374 sprintf(tbuf, "%pI4", n->key); 1375 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1376 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1377 dev ? dev->name : "*"); 1378 } 1379 1380 static int arp_seq_show(struct seq_file *seq, void *v) 1381 { 1382 if (v == SEQ_START_TOKEN) { 1383 seq_puts(seq, "IP address HW type Flags " 1384 "HW address Mask Device\n"); 1385 } else { 1386 struct neigh_seq_state *state = seq->private; 1387 1388 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1389 arp_format_pneigh_entry(seq, v); 1390 else 1391 arp_format_neigh_entry(seq, v); 1392 } 1393 1394 return 0; 1395 } 1396 1397 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1398 { 1399 /* Don't want to confuse "arp -a" w/ magic entries, 1400 * so we tell the generic iterator to skip NUD_NOARP. 1401 */ 1402 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1403 } 1404 1405 /* ------------------------------------------------------------------------ */ 1406 1407 static const struct seq_operations arp_seq_ops = { 1408 .start = arp_seq_start, 1409 .next = neigh_seq_next, 1410 .stop = neigh_seq_stop, 1411 .show = arp_seq_show, 1412 }; 1413 1414 static int arp_seq_open(struct inode *inode, struct file *file) 1415 { 1416 return seq_open_net(inode, file, &arp_seq_ops, 1417 sizeof(struct neigh_seq_state)); 1418 } 1419 1420 static const struct file_operations arp_seq_fops = { 1421 .owner = THIS_MODULE, 1422 .open = arp_seq_open, 1423 .read = seq_read, 1424 .llseek = seq_lseek, 1425 .release = seq_release_net, 1426 }; 1427 1428 1429 static int __net_init arp_net_init(struct net *net) 1430 { 1431 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops)) 1432 return -ENOMEM; 1433 return 0; 1434 } 1435 1436 static void __net_exit arp_net_exit(struct net *net) 1437 { 1438 remove_proc_entry("arp", net->proc_net); 1439 } 1440 1441 static struct pernet_operations arp_net_ops = { 1442 .init = arp_net_init, 1443 .exit = arp_net_exit, 1444 }; 1445 1446 static int __init arp_proc_init(void) 1447 { 1448 return register_pernet_subsys(&arp_net_ops); 1449 } 1450 1451 #else /* CONFIG_PROC_FS */ 1452 1453 static int __init arp_proc_init(void) 1454 { 1455 return 0; 1456 } 1457 1458 #endif /* CONFIG_PROC_FS */ 1459