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 #include <net/dst_metadata.h> 117 #include <net/ip_tunnels.h> 118 119 #include <linux/uaccess.h> 120 121 #include <linux/netfilter_arp.h> 122 123 /* 124 * Interface to generic neighbour cache. 125 */ 126 static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); 127 static bool arp_key_eq(const struct neighbour *n, const void *pkey); 128 static int arp_constructor(struct neighbour *neigh); 129 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 130 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 131 static void parp_redo(struct sk_buff *skb); 132 133 static const struct neigh_ops arp_generic_ops = { 134 .family = AF_INET, 135 .solicit = arp_solicit, 136 .error_report = arp_error_report, 137 .output = neigh_resolve_output, 138 .connected_output = neigh_connected_output, 139 }; 140 141 static const struct neigh_ops arp_hh_ops = { 142 .family = AF_INET, 143 .solicit = arp_solicit, 144 .error_report = arp_error_report, 145 .output = neigh_resolve_output, 146 .connected_output = neigh_resolve_output, 147 }; 148 149 static const struct neigh_ops arp_direct_ops = { 150 .family = AF_INET, 151 .output = neigh_direct_output, 152 .connected_output = neigh_direct_output, 153 }; 154 155 struct neigh_table arp_tbl = { 156 .family = AF_INET, 157 .key_len = 4, 158 .protocol = cpu_to_be16(ETH_P_IP), 159 .hash = arp_hash, 160 .key_eq = arp_key_eq, 161 .constructor = arp_constructor, 162 .proxy_redo = parp_redo, 163 .id = "arp_cache", 164 .parms = { 165 .tbl = &arp_tbl, 166 .reachable_time = 30 * HZ, 167 .data = { 168 [NEIGH_VAR_MCAST_PROBES] = 3, 169 [NEIGH_VAR_UCAST_PROBES] = 3, 170 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ, 171 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ, 172 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ, 173 [NEIGH_VAR_GC_STALETIME] = 60 * HZ, 174 [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024, 175 [NEIGH_VAR_PROXY_QLEN] = 64, 176 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ, 177 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10, 178 [NEIGH_VAR_LOCKTIME] = 1 * HZ, 179 }, 180 }, 181 .gc_interval = 30 * HZ, 182 .gc_thresh1 = 128, 183 .gc_thresh2 = 512, 184 .gc_thresh3 = 1024, 185 }; 186 EXPORT_SYMBOL(arp_tbl); 187 188 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 189 { 190 switch (dev->type) { 191 case ARPHRD_ETHER: 192 case ARPHRD_FDDI: 193 case ARPHRD_IEEE802: 194 ip_eth_mc_map(addr, haddr); 195 return 0; 196 case ARPHRD_INFINIBAND: 197 ip_ib_mc_map(addr, dev->broadcast, haddr); 198 return 0; 199 case ARPHRD_IPGRE: 200 ip_ipgre_mc_map(addr, dev->broadcast, haddr); 201 return 0; 202 default: 203 if (dir) { 204 memcpy(haddr, dev->broadcast, dev->addr_len); 205 return 0; 206 } 207 } 208 return -EINVAL; 209 } 210 211 212 static u32 arp_hash(const void *pkey, 213 const struct net_device *dev, 214 __u32 *hash_rnd) 215 { 216 return arp_hashfn(pkey, dev, hash_rnd); 217 } 218 219 static bool arp_key_eq(const struct neighbour *neigh, const void *pkey) 220 { 221 return neigh_key_eq32(neigh, pkey); 222 } 223 224 static int arp_constructor(struct neighbour *neigh) 225 { 226 __be32 addr = *(__be32 *)neigh->primary_key; 227 struct net_device *dev = neigh->dev; 228 struct in_device *in_dev; 229 struct neigh_parms *parms; 230 231 rcu_read_lock(); 232 in_dev = __in_dev_get_rcu(dev); 233 if (!in_dev) { 234 rcu_read_unlock(); 235 return -EINVAL; 236 } 237 238 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr); 239 240 parms = in_dev->arp_parms; 241 __neigh_parms_put(neigh->parms); 242 neigh->parms = neigh_parms_clone(parms); 243 rcu_read_unlock(); 244 245 if (!dev->header_ops) { 246 neigh->nud_state = NUD_NOARP; 247 neigh->ops = &arp_direct_ops; 248 neigh->output = neigh_direct_output; 249 } else { 250 /* Good devices (checked by reading texts, but only Ethernet is 251 tested) 252 253 ARPHRD_ETHER: (ethernet, apfddi) 254 ARPHRD_FDDI: (fddi) 255 ARPHRD_IEEE802: (tr) 256 ARPHRD_METRICOM: (strip) 257 ARPHRD_ARCNET: 258 etc. etc. etc. 259 260 ARPHRD_IPDDP will also work, if author repairs it. 261 I did not it, because this driver does not work even 262 in old paradigm. 263 */ 264 265 if (neigh->type == RTN_MULTICAST) { 266 neigh->nud_state = NUD_NOARP; 267 arp_mc_map(addr, neigh->ha, dev, 1); 268 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 269 neigh->nud_state = NUD_NOARP; 270 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 271 } else if (neigh->type == RTN_BROADCAST || 272 (dev->flags & IFF_POINTOPOINT)) { 273 neigh->nud_state = NUD_NOARP; 274 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 275 } 276 277 if (dev->header_ops->cache) 278 neigh->ops = &arp_hh_ops; 279 else 280 neigh->ops = &arp_generic_ops; 281 282 if (neigh->nud_state & NUD_VALID) 283 neigh->output = neigh->ops->connected_output; 284 else 285 neigh->output = neigh->ops->output; 286 } 287 return 0; 288 } 289 290 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 291 { 292 dst_link_failure(skb); 293 kfree_skb(skb); 294 } 295 296 /* Create and send an arp packet. */ 297 static void arp_send_dst(int type, int ptype, __be32 dest_ip, 298 struct net_device *dev, __be32 src_ip, 299 const unsigned char *dest_hw, 300 const unsigned char *src_hw, 301 const unsigned char *target_hw, 302 struct dst_entry *dst) 303 { 304 struct sk_buff *skb; 305 306 /* arp on this interface. */ 307 if (dev->flags & IFF_NOARP) 308 return; 309 310 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 311 dest_hw, src_hw, target_hw); 312 if (!skb) 313 return; 314 315 skb_dst_set(skb, dst_clone(dst)); 316 arp_xmit(skb); 317 } 318 319 void arp_send(int type, int ptype, __be32 dest_ip, 320 struct net_device *dev, __be32 src_ip, 321 const unsigned char *dest_hw, const unsigned char *src_hw, 322 const unsigned char *target_hw) 323 { 324 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw, 325 target_hw, NULL); 326 } 327 EXPORT_SYMBOL(arp_send); 328 329 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 330 { 331 __be32 saddr = 0; 332 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL; 333 struct net_device *dev = neigh->dev; 334 __be32 target = *(__be32 *)neigh->primary_key; 335 int probes = atomic_read(&neigh->probes); 336 struct in_device *in_dev; 337 struct dst_entry *dst = NULL; 338 339 rcu_read_lock(); 340 in_dev = __in_dev_get_rcu(dev); 341 if (!in_dev) { 342 rcu_read_unlock(); 343 return; 344 } 345 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 346 default: 347 case 0: /* By default announce any local IP */ 348 if (skb && inet_addr_type_dev_table(dev_net(dev), dev, 349 ip_hdr(skb)->saddr) == RTN_LOCAL) 350 saddr = ip_hdr(skb)->saddr; 351 break; 352 case 1: /* Restrict announcements of saddr in same subnet */ 353 if (!skb) 354 break; 355 saddr = ip_hdr(skb)->saddr; 356 if (inet_addr_type_dev_table(dev_net(dev), dev, 357 saddr) == RTN_LOCAL) { 358 /* saddr should be known to target */ 359 if (inet_addr_onlink(in_dev, target, saddr)) 360 break; 361 } 362 saddr = 0; 363 break; 364 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 365 break; 366 } 367 rcu_read_unlock(); 368 369 if (!saddr) 370 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 371 372 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); 373 if (probes < 0) { 374 if (!(neigh->nud_state & NUD_VALID)) 375 pr_debug("trying to ucast probe in NUD_INVALID\n"); 376 neigh_ha_snapshot(dst_ha, neigh, dev); 377 dst_hw = dst_ha; 378 } else { 379 probes -= NEIGH_VAR(neigh->parms, APP_PROBES); 380 if (probes < 0) { 381 neigh_app_ns(neigh); 382 return; 383 } 384 } 385 386 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE)) 387 dst = skb_dst(skb); 388 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 389 dst_hw, dev->dev_addr, NULL, dst); 390 } 391 392 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 393 { 394 struct net *net = dev_net(in_dev->dev); 395 int scope; 396 397 switch (IN_DEV_ARP_IGNORE(in_dev)) { 398 case 0: /* Reply, the tip is already validated */ 399 return 0; 400 case 1: /* Reply only if tip is configured on the incoming interface */ 401 sip = 0; 402 scope = RT_SCOPE_HOST; 403 break; 404 case 2: /* 405 * Reply only if tip is configured on the incoming interface 406 * and is in same subnet as sip 407 */ 408 scope = RT_SCOPE_HOST; 409 break; 410 case 3: /* Do not reply for scope host addresses */ 411 sip = 0; 412 scope = RT_SCOPE_LINK; 413 in_dev = NULL; 414 break; 415 case 4: /* Reserved */ 416 case 5: 417 case 6: 418 case 7: 419 return 0; 420 case 8: /* Do not reply */ 421 return 1; 422 default: 423 return 0; 424 } 425 return !inet_confirm_addr(net, in_dev, sip, tip, scope); 426 } 427 428 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 429 { 430 struct rtable *rt; 431 int flag = 0; 432 /*unsigned long now; */ 433 struct net *net = dev_net(dev); 434 435 rt = ip_route_output(net, sip, tip, 0, 0); 436 if (IS_ERR(rt)) 437 return 1; 438 if (rt->dst.dev != dev) { 439 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER); 440 flag = 1; 441 } 442 ip_rt_put(rt); 443 return flag; 444 } 445 446 /* 447 * Check if we can use proxy ARP for this path 448 */ 449 static inline int arp_fwd_proxy(struct in_device *in_dev, 450 struct net_device *dev, struct rtable *rt) 451 { 452 struct in_device *out_dev; 453 int imi, omi = -1; 454 455 if (rt->dst.dev == dev) 456 return 0; 457 458 if (!IN_DEV_PROXY_ARP(in_dev)) 459 return 0; 460 imi = IN_DEV_MEDIUM_ID(in_dev); 461 if (imi == 0) 462 return 1; 463 if (imi == -1) 464 return 0; 465 466 /* place to check for proxy_arp for routes */ 467 468 out_dev = __in_dev_get_rcu(rt->dst.dev); 469 if (out_dev) 470 omi = IN_DEV_MEDIUM_ID(out_dev); 471 472 return omi != imi && omi != -1; 473 } 474 475 /* 476 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 477 * 478 * RFC3069 supports proxy arp replies back to the same interface. This 479 * is done to support (ethernet) switch features, like RFC 3069, where 480 * the individual ports are not allowed to communicate with each 481 * other, BUT they are allowed to talk to the upstream router. As 482 * described in RFC 3069, it is possible to allow these hosts to 483 * communicate through the upstream router, by proxy_arp'ing. 484 * 485 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 486 * 487 * This technology is known by different names: 488 * In RFC 3069 it is called VLAN Aggregation. 489 * Cisco and Allied Telesyn call it Private VLAN. 490 * Hewlett-Packard call it Source-Port filtering or port-isolation. 491 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 492 * 493 */ 494 static inline int arp_fwd_pvlan(struct in_device *in_dev, 495 struct net_device *dev, struct rtable *rt, 496 __be32 sip, __be32 tip) 497 { 498 /* Private VLAN is only concerned about the same ethernet segment */ 499 if (rt->dst.dev != dev) 500 return 0; 501 502 /* Don't reply on self probes (often done by windowz boxes)*/ 503 if (sip == tip) 504 return 0; 505 506 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 507 return 1; 508 else 509 return 0; 510 } 511 512 /* 513 * Interface to link layer: send routine and receive handler. 514 */ 515 516 /* 517 * Create an arp packet. If dest_hw is not set, we create a broadcast 518 * message. 519 */ 520 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 521 struct net_device *dev, __be32 src_ip, 522 const unsigned char *dest_hw, 523 const unsigned char *src_hw, 524 const unsigned char *target_hw) 525 { 526 struct sk_buff *skb; 527 struct arphdr *arp; 528 unsigned char *arp_ptr; 529 int hlen = LL_RESERVED_SPACE(dev); 530 int tlen = dev->needed_tailroom; 531 532 /* 533 * Allocate a buffer 534 */ 535 536 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 537 if (!skb) 538 return NULL; 539 540 skb_reserve(skb, hlen); 541 skb_reset_network_header(skb); 542 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); 543 skb->dev = dev; 544 skb->protocol = htons(ETH_P_ARP); 545 if (!src_hw) 546 src_hw = dev->dev_addr; 547 if (!dest_hw) 548 dest_hw = dev->broadcast; 549 550 /* 551 * Fill the device header for the ARP frame 552 */ 553 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 554 goto out; 555 556 /* 557 * Fill out the arp protocol part. 558 * 559 * The arp hardware type should match the device type, except for FDDI, 560 * which (according to RFC 1390) should always equal 1 (Ethernet). 561 */ 562 /* 563 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 564 * DIX code for the protocol. Make these device structure fields. 565 */ 566 switch (dev->type) { 567 default: 568 arp->ar_hrd = htons(dev->type); 569 arp->ar_pro = htons(ETH_P_IP); 570 break; 571 572 #if IS_ENABLED(CONFIG_AX25) 573 case ARPHRD_AX25: 574 arp->ar_hrd = htons(ARPHRD_AX25); 575 arp->ar_pro = htons(AX25_P_IP); 576 break; 577 578 #if IS_ENABLED(CONFIG_NETROM) 579 case ARPHRD_NETROM: 580 arp->ar_hrd = htons(ARPHRD_NETROM); 581 arp->ar_pro = htons(AX25_P_IP); 582 break; 583 #endif 584 #endif 585 586 #if IS_ENABLED(CONFIG_FDDI) 587 case ARPHRD_FDDI: 588 arp->ar_hrd = htons(ARPHRD_ETHER); 589 arp->ar_pro = htons(ETH_P_IP); 590 break; 591 #endif 592 } 593 594 arp->ar_hln = dev->addr_len; 595 arp->ar_pln = 4; 596 arp->ar_op = htons(type); 597 598 arp_ptr = (unsigned char *)(arp + 1); 599 600 memcpy(arp_ptr, src_hw, dev->addr_len); 601 arp_ptr += dev->addr_len; 602 memcpy(arp_ptr, &src_ip, 4); 603 arp_ptr += 4; 604 605 switch (dev->type) { 606 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 607 case ARPHRD_IEEE1394: 608 break; 609 #endif 610 default: 611 if (target_hw) 612 memcpy(arp_ptr, target_hw, dev->addr_len); 613 else 614 memset(arp_ptr, 0, dev->addr_len); 615 arp_ptr += dev->addr_len; 616 } 617 memcpy(arp_ptr, &dest_ip, 4); 618 619 return skb; 620 621 out: 622 kfree_skb(skb); 623 return NULL; 624 } 625 EXPORT_SYMBOL(arp_create); 626 627 static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 628 { 629 return dev_queue_xmit(skb); 630 } 631 632 /* 633 * Send an arp packet. 634 */ 635 void arp_xmit(struct sk_buff *skb) 636 { 637 /* Send it off, maybe filter it using firewalling first. */ 638 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, 639 dev_net(skb->dev), NULL, skb, NULL, skb->dev, 640 arp_xmit_finish); 641 } 642 EXPORT_SYMBOL(arp_xmit); 643 644 /* 645 * Process an arp request. 646 */ 647 648 static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb) 649 { 650 struct net_device *dev = skb->dev; 651 struct in_device *in_dev = __in_dev_get_rcu(dev); 652 struct arphdr *arp; 653 unsigned char *arp_ptr; 654 struct rtable *rt; 655 unsigned char *sha; 656 unsigned char *tha = NULL; 657 __be32 sip, tip; 658 u16 dev_type = dev->type; 659 int addr_type; 660 struct neighbour *n; 661 struct dst_entry *reply_dst = NULL; 662 bool is_garp = false; 663 664 /* arp_rcv below verifies the ARP header and verifies the device 665 * is ARP'able. 666 */ 667 668 if (!in_dev) 669 goto out_free_skb; 670 671 arp = arp_hdr(skb); 672 673 switch (dev_type) { 674 default: 675 if (arp->ar_pro != htons(ETH_P_IP) || 676 htons(dev_type) != arp->ar_hrd) 677 goto out_free_skb; 678 break; 679 case ARPHRD_ETHER: 680 case ARPHRD_FDDI: 681 case ARPHRD_IEEE802: 682 /* 683 * ETHERNET, and Fibre Channel (which are IEEE 802 684 * devices, according to RFC 2625) devices will accept ARP 685 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 686 * This is the case also of FDDI, where the RFC 1390 says that 687 * FDDI devices should accept ARP hardware of (1) Ethernet, 688 * however, to be more robust, we'll accept both 1 (Ethernet) 689 * or 6 (IEEE 802.2) 690 */ 691 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 692 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 693 arp->ar_pro != htons(ETH_P_IP)) 694 goto out_free_skb; 695 break; 696 case ARPHRD_AX25: 697 if (arp->ar_pro != htons(AX25_P_IP) || 698 arp->ar_hrd != htons(ARPHRD_AX25)) 699 goto out_free_skb; 700 break; 701 case ARPHRD_NETROM: 702 if (arp->ar_pro != htons(AX25_P_IP) || 703 arp->ar_hrd != htons(ARPHRD_NETROM)) 704 goto out_free_skb; 705 break; 706 } 707 708 /* Understand only these message types */ 709 710 if (arp->ar_op != htons(ARPOP_REPLY) && 711 arp->ar_op != htons(ARPOP_REQUEST)) 712 goto out_free_skb; 713 714 /* 715 * Extract fields 716 */ 717 arp_ptr = (unsigned char *)(arp + 1); 718 sha = arp_ptr; 719 arp_ptr += dev->addr_len; 720 memcpy(&sip, arp_ptr, 4); 721 arp_ptr += 4; 722 switch (dev_type) { 723 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 724 case ARPHRD_IEEE1394: 725 break; 726 #endif 727 default: 728 tha = arp_ptr; 729 arp_ptr += dev->addr_len; 730 } 731 memcpy(&tip, arp_ptr, 4); 732 /* 733 * Check for bad requests for 127.x.x.x and requests for multicast 734 * addresses. If this is one such, delete it. 735 */ 736 if (ipv4_is_multicast(tip) || 737 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) 738 goto out_free_skb; 739 740 /* 741 * For some 802.11 wireless deployments (and possibly other networks), 742 * there will be an ARP proxy and gratuitous ARP frames are attacks 743 * and thus should not be accepted. 744 */ 745 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP)) 746 goto out_free_skb; 747 748 /* 749 * Special case: We must set Frame Relay source Q.922 address 750 */ 751 if (dev_type == ARPHRD_DLCI) 752 sha = dev->broadcast; 753 754 /* 755 * Process entry. The idea here is we want to send a reply if it is a 756 * request for us or if it is a request for someone else that we hold 757 * a proxy for. We want to add an entry to our cache if it is a reply 758 * to us or if it is a request for our address. 759 * (The assumption for this last is that if someone is requesting our 760 * address, they are probably intending to talk to us, so it saves time 761 * if we cache their address. Their address is also probably not in 762 * our cache, since ours is not in their cache.) 763 * 764 * Putting this another way, we only care about replies if they are to 765 * us, in which case we add them to the cache. For requests, we care 766 * about those for us and those for our proxies. We reply to both, 767 * and in the case of requests for us we add the requester to the arp 768 * cache. 769 */ 770 771 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb)) 772 reply_dst = (struct dst_entry *) 773 iptunnel_metadata_reply(skb_metadata_dst(skb), 774 GFP_ATOMIC); 775 776 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 777 if (sip == 0) { 778 if (arp->ar_op == htons(ARPOP_REQUEST) && 779 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL && 780 !arp_ignore(in_dev, sip, tip)) 781 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, 782 sha, dev->dev_addr, sha, reply_dst); 783 goto out_consume_skb; 784 } 785 786 if (arp->ar_op == htons(ARPOP_REQUEST) && 787 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 788 789 rt = skb_rtable(skb); 790 addr_type = rt->rt_type; 791 792 if (addr_type == RTN_LOCAL) { 793 int dont_send; 794 795 dont_send = arp_ignore(in_dev, sip, tip); 796 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 797 dont_send = arp_filter(sip, tip, dev); 798 if (!dont_send) { 799 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 800 if (n) { 801 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 802 sip, dev, tip, sha, 803 dev->dev_addr, sha, 804 reply_dst); 805 neigh_release(n); 806 } 807 } 808 goto out_consume_skb; 809 } else if (IN_DEV_FORWARD(in_dev)) { 810 if (addr_type == RTN_UNICAST && 811 (arp_fwd_proxy(in_dev, dev, rt) || 812 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 813 (rt->dst.dev != dev && 814 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 815 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 816 if (n) 817 neigh_release(n); 818 819 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 820 skb->pkt_type == PACKET_HOST || 821 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { 822 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 823 sip, dev, tip, sha, 824 dev->dev_addr, sha, 825 reply_dst); 826 } else { 827 pneigh_enqueue(&arp_tbl, 828 in_dev->arp_parms, skb); 829 goto out_free_dst; 830 } 831 goto out_consume_skb; 832 } 833 } 834 } 835 836 /* Update our ARP tables */ 837 838 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 839 840 if (IN_DEV_ARP_ACCEPT(in_dev)) { 841 unsigned int addr_type = inet_addr_type_dev_table(net, dev, sip); 842 843 /* Unsolicited ARP is not accepted by default. 844 It is possible, that this option should be enabled for some 845 devices (strip is candidate) 846 */ 847 is_garp = tip == sip && addr_type == RTN_UNICAST; 848 849 /* Unsolicited ARP _replies_ also require target hwaddr to be 850 * the same as source. 851 */ 852 if (is_garp && arp->ar_op == htons(ARPOP_REPLY)) 853 is_garp = 854 /* IPv4 over IEEE 1394 doesn't provide target 855 * hardware address field in its ARP payload. 856 */ 857 tha && 858 !memcmp(tha, sha, dev->addr_len); 859 860 if (!n && 861 ((arp->ar_op == htons(ARPOP_REPLY) && 862 addr_type == RTN_UNICAST) || is_garp)) 863 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 864 } 865 866 if (n) { 867 int state = NUD_REACHABLE; 868 int override; 869 870 /* If several different ARP replies follows back-to-back, 871 use the FIRST one. It is possible, if several proxy 872 agents are active. Taking the first reply prevents 873 arp trashing and chooses the fastest router. 874 */ 875 override = time_after(jiffies, 876 n->updated + 877 NEIGH_VAR(n->parms, LOCKTIME)) || 878 is_garp; 879 880 /* Broadcast replies and request packets 881 do not assert neighbour reachability. 882 */ 883 if (arp->ar_op != htons(ARPOP_REPLY) || 884 skb->pkt_type != PACKET_HOST) 885 state = NUD_STALE; 886 neigh_update(n, sha, state, 887 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0); 888 neigh_release(n); 889 } 890 891 out_consume_skb: 892 consume_skb(skb); 893 894 out_free_dst: 895 dst_release(reply_dst); 896 return NET_RX_SUCCESS; 897 898 out_free_skb: 899 kfree_skb(skb); 900 return NET_RX_DROP; 901 } 902 903 static void parp_redo(struct sk_buff *skb) 904 { 905 arp_process(dev_net(skb->dev), NULL, skb); 906 } 907 908 909 /* 910 * Receive an arp request from the device layer. 911 */ 912 913 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 914 struct packet_type *pt, struct net_device *orig_dev) 915 { 916 const struct arphdr *arp; 917 918 /* do not tweak dropwatch on an ARP we will ignore */ 919 if (dev->flags & IFF_NOARP || 920 skb->pkt_type == PACKET_OTHERHOST || 921 skb->pkt_type == PACKET_LOOPBACK) 922 goto consumeskb; 923 924 skb = skb_share_check(skb, GFP_ATOMIC); 925 if (!skb) 926 goto out_of_mem; 927 928 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 929 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 930 goto freeskb; 931 932 arp = arp_hdr(skb); 933 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 934 goto freeskb; 935 936 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 937 938 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, 939 dev_net(dev), NULL, skb, dev, NULL, 940 arp_process); 941 942 consumeskb: 943 consume_skb(skb); 944 return NET_RX_SUCCESS; 945 freeskb: 946 kfree_skb(skb); 947 out_of_mem: 948 return NET_RX_DROP; 949 } 950 951 /* 952 * User level interface (ioctl) 953 */ 954 955 /* 956 * Set (create) an ARP cache entry. 957 */ 958 959 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 960 { 961 if (!dev) { 962 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 963 return 0; 964 } 965 if (__in_dev_get_rtnl(dev)) { 966 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 967 return 0; 968 } 969 return -ENXIO; 970 } 971 972 static int arp_req_set_public(struct net *net, struct arpreq *r, 973 struct net_device *dev) 974 { 975 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 976 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 977 978 if (mask && mask != htonl(0xFFFFFFFF)) 979 return -EINVAL; 980 if (!dev && (r->arp_flags & ATF_COM)) { 981 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 982 r->arp_ha.sa_data); 983 if (!dev) 984 return -ENODEV; 985 } 986 if (mask) { 987 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1)) 988 return -ENOBUFS; 989 return 0; 990 } 991 992 return arp_req_set_proxy(net, dev, 1); 993 } 994 995 static int arp_req_set(struct net *net, struct arpreq *r, 996 struct net_device *dev) 997 { 998 __be32 ip; 999 struct neighbour *neigh; 1000 int err; 1001 1002 if (r->arp_flags & ATF_PUBL) 1003 return arp_req_set_public(net, r, dev); 1004 1005 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1006 if (r->arp_flags & ATF_PERM) 1007 r->arp_flags |= ATF_COM; 1008 if (!dev) { 1009 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1010 1011 if (IS_ERR(rt)) 1012 return PTR_ERR(rt); 1013 dev = rt->dst.dev; 1014 ip_rt_put(rt); 1015 if (!dev) 1016 return -EINVAL; 1017 } 1018 switch (dev->type) { 1019 #if IS_ENABLED(CONFIG_FDDI) 1020 case ARPHRD_FDDI: 1021 /* 1022 * According to RFC 1390, FDDI devices should accept ARP 1023 * hardware types of 1 (Ethernet). However, to be more 1024 * robust, we'll accept hardware types of either 1 (Ethernet) 1025 * or 6 (IEEE 802.2). 1026 */ 1027 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1028 r->arp_ha.sa_family != ARPHRD_ETHER && 1029 r->arp_ha.sa_family != ARPHRD_IEEE802) 1030 return -EINVAL; 1031 break; 1032 #endif 1033 default: 1034 if (r->arp_ha.sa_family != dev->type) 1035 return -EINVAL; 1036 break; 1037 } 1038 1039 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1040 err = PTR_ERR(neigh); 1041 if (!IS_ERR(neigh)) { 1042 unsigned int state = NUD_STALE; 1043 if (r->arp_flags & ATF_PERM) 1044 state = NUD_PERMANENT; 1045 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1046 r->arp_ha.sa_data : NULL, state, 1047 NEIGH_UPDATE_F_OVERRIDE | 1048 NEIGH_UPDATE_F_ADMIN, 0); 1049 neigh_release(neigh); 1050 } 1051 return err; 1052 } 1053 1054 static unsigned int arp_state_to_flags(struct neighbour *neigh) 1055 { 1056 if (neigh->nud_state&NUD_PERMANENT) 1057 return ATF_PERM | ATF_COM; 1058 else if (neigh->nud_state&NUD_VALID) 1059 return ATF_COM; 1060 else 1061 return 0; 1062 } 1063 1064 /* 1065 * Get an ARP cache entry. 1066 */ 1067 1068 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1069 { 1070 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1071 struct neighbour *neigh; 1072 int err = -ENXIO; 1073 1074 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1075 if (neigh) { 1076 if (!(neigh->nud_state & NUD_NOARP)) { 1077 read_lock_bh(&neigh->lock); 1078 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1079 r->arp_flags = arp_state_to_flags(neigh); 1080 read_unlock_bh(&neigh->lock); 1081 r->arp_ha.sa_family = dev->type; 1082 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1083 err = 0; 1084 } 1085 neigh_release(neigh); 1086 } 1087 return err; 1088 } 1089 1090 static int arp_invalidate(struct net_device *dev, __be32 ip) 1091 { 1092 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1093 int err = -ENXIO; 1094 1095 if (neigh) { 1096 if (neigh->nud_state & ~NUD_NOARP) 1097 err = neigh_update(neigh, NULL, NUD_FAILED, 1098 NEIGH_UPDATE_F_OVERRIDE| 1099 NEIGH_UPDATE_F_ADMIN, 0); 1100 neigh_release(neigh); 1101 } 1102 1103 return err; 1104 } 1105 1106 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1107 struct net_device *dev) 1108 { 1109 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1110 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1111 1112 if (mask == htonl(0xFFFFFFFF)) 1113 return pneigh_delete(&arp_tbl, net, &ip, dev); 1114 1115 if (mask) 1116 return -EINVAL; 1117 1118 return arp_req_set_proxy(net, dev, 0); 1119 } 1120 1121 static int arp_req_delete(struct net *net, struct arpreq *r, 1122 struct net_device *dev) 1123 { 1124 __be32 ip; 1125 1126 if (r->arp_flags & ATF_PUBL) 1127 return arp_req_delete_public(net, r, dev); 1128 1129 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1130 if (!dev) { 1131 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1132 if (IS_ERR(rt)) 1133 return PTR_ERR(rt); 1134 dev = rt->dst.dev; 1135 ip_rt_put(rt); 1136 if (!dev) 1137 return -EINVAL; 1138 } 1139 return arp_invalidate(dev, ip); 1140 } 1141 1142 /* 1143 * Handle an ARP layer I/O control request. 1144 */ 1145 1146 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1147 { 1148 int err; 1149 struct arpreq r; 1150 struct net_device *dev = NULL; 1151 1152 switch (cmd) { 1153 case SIOCDARP: 1154 case SIOCSARP: 1155 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1156 return -EPERM; 1157 case SIOCGARP: 1158 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1159 if (err) 1160 return -EFAULT; 1161 break; 1162 default: 1163 return -EINVAL; 1164 } 1165 1166 if (r.arp_pa.sa_family != AF_INET) 1167 return -EPFNOSUPPORT; 1168 1169 if (!(r.arp_flags & ATF_PUBL) && 1170 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1171 return -EINVAL; 1172 if (!(r.arp_flags & ATF_NETMASK)) 1173 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1174 htonl(0xFFFFFFFFUL); 1175 rtnl_lock(); 1176 if (r.arp_dev[0]) { 1177 err = -ENODEV; 1178 dev = __dev_get_by_name(net, r.arp_dev); 1179 if (!dev) 1180 goto out; 1181 1182 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1183 if (!r.arp_ha.sa_family) 1184 r.arp_ha.sa_family = dev->type; 1185 err = -EINVAL; 1186 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1187 goto out; 1188 } else if (cmd == SIOCGARP) { 1189 err = -ENODEV; 1190 goto out; 1191 } 1192 1193 switch (cmd) { 1194 case SIOCDARP: 1195 err = arp_req_delete(net, &r, dev); 1196 break; 1197 case SIOCSARP: 1198 err = arp_req_set(net, &r, dev); 1199 break; 1200 case SIOCGARP: 1201 err = arp_req_get(&r, dev); 1202 break; 1203 } 1204 out: 1205 rtnl_unlock(); 1206 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1207 err = -EFAULT; 1208 return err; 1209 } 1210 1211 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1212 void *ptr) 1213 { 1214 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1215 struct netdev_notifier_change_info *change_info; 1216 1217 switch (event) { 1218 case NETDEV_CHANGEADDR: 1219 neigh_changeaddr(&arp_tbl, dev); 1220 rt_cache_flush(dev_net(dev)); 1221 break; 1222 case NETDEV_CHANGE: 1223 change_info = ptr; 1224 if (change_info->flags_changed & IFF_NOARP) 1225 neigh_changeaddr(&arp_tbl, dev); 1226 break; 1227 default: 1228 break; 1229 } 1230 1231 return NOTIFY_DONE; 1232 } 1233 1234 static struct notifier_block arp_netdev_notifier = { 1235 .notifier_call = arp_netdev_event, 1236 }; 1237 1238 /* Note, that it is not on notifier chain. 1239 It is necessary, that this routine was called after route cache will be 1240 flushed. 1241 */ 1242 void arp_ifdown(struct net_device *dev) 1243 { 1244 neigh_ifdown(&arp_tbl, dev); 1245 } 1246 1247 1248 /* 1249 * Called once on startup. 1250 */ 1251 1252 static struct packet_type arp_packet_type __read_mostly = { 1253 .type = cpu_to_be16(ETH_P_ARP), 1254 .func = arp_rcv, 1255 }; 1256 1257 static int arp_proc_init(void); 1258 1259 void __init arp_init(void) 1260 { 1261 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl); 1262 1263 dev_add_pack(&arp_packet_type); 1264 arp_proc_init(); 1265 #ifdef CONFIG_SYSCTL 1266 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL); 1267 #endif 1268 register_netdevice_notifier(&arp_netdev_notifier); 1269 } 1270 1271 #ifdef CONFIG_PROC_FS 1272 #if IS_ENABLED(CONFIG_AX25) 1273 1274 /* ------------------------------------------------------------------------ */ 1275 /* 1276 * ax25 -> ASCII conversion 1277 */ 1278 static void ax2asc2(ax25_address *a, char *buf) 1279 { 1280 char c, *s; 1281 int n; 1282 1283 for (n = 0, s = buf; n < 6; n++) { 1284 c = (a->ax25_call[n] >> 1) & 0x7F; 1285 1286 if (c != ' ') 1287 *s++ = c; 1288 } 1289 1290 *s++ = '-'; 1291 n = (a->ax25_call[6] >> 1) & 0x0F; 1292 if (n > 9) { 1293 *s++ = '1'; 1294 n -= 10; 1295 } 1296 1297 *s++ = n + '0'; 1298 *s++ = '\0'; 1299 1300 if (*buf == '\0' || *buf == '-') { 1301 buf[0] = '*'; 1302 buf[1] = '\0'; 1303 } 1304 } 1305 #endif /* CONFIG_AX25 */ 1306 1307 #define HBUFFERLEN 30 1308 1309 static void arp_format_neigh_entry(struct seq_file *seq, 1310 struct neighbour *n) 1311 { 1312 char hbuffer[HBUFFERLEN]; 1313 int k, j; 1314 char tbuf[16]; 1315 struct net_device *dev = n->dev; 1316 int hatype = dev->type; 1317 1318 read_lock(&n->lock); 1319 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1320 #if IS_ENABLED(CONFIG_AX25) 1321 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1322 ax2asc2((ax25_address *)n->ha, hbuffer); 1323 else { 1324 #endif 1325 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1326 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1327 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1328 hbuffer[k++] = ':'; 1329 } 1330 if (k != 0) 1331 --k; 1332 hbuffer[k] = 0; 1333 #if IS_ENABLED(CONFIG_AX25) 1334 } 1335 #endif 1336 sprintf(tbuf, "%pI4", n->primary_key); 1337 seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n", 1338 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1339 read_unlock(&n->lock); 1340 } 1341 1342 static void arp_format_pneigh_entry(struct seq_file *seq, 1343 struct pneigh_entry *n) 1344 { 1345 struct net_device *dev = n->dev; 1346 int hatype = dev ? dev->type : 0; 1347 char tbuf[16]; 1348 1349 sprintf(tbuf, "%pI4", n->key); 1350 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1351 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1352 dev ? dev->name : "*"); 1353 } 1354 1355 static int arp_seq_show(struct seq_file *seq, void *v) 1356 { 1357 if (v == SEQ_START_TOKEN) { 1358 seq_puts(seq, "IP address HW type Flags " 1359 "HW address Mask Device\n"); 1360 } else { 1361 struct neigh_seq_state *state = seq->private; 1362 1363 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1364 arp_format_pneigh_entry(seq, v); 1365 else 1366 arp_format_neigh_entry(seq, v); 1367 } 1368 1369 return 0; 1370 } 1371 1372 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1373 { 1374 /* Don't want to confuse "arp -a" w/ magic entries, 1375 * so we tell the generic iterator to skip NUD_NOARP. 1376 */ 1377 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1378 } 1379 1380 /* ------------------------------------------------------------------------ */ 1381 1382 static const struct seq_operations arp_seq_ops = { 1383 .start = arp_seq_start, 1384 .next = neigh_seq_next, 1385 .stop = neigh_seq_stop, 1386 .show = arp_seq_show, 1387 }; 1388 1389 static int arp_seq_open(struct inode *inode, struct file *file) 1390 { 1391 return seq_open_net(inode, file, &arp_seq_ops, 1392 sizeof(struct neigh_seq_state)); 1393 } 1394 1395 static const struct file_operations arp_seq_fops = { 1396 .owner = THIS_MODULE, 1397 .open = arp_seq_open, 1398 .read = seq_read, 1399 .llseek = seq_lseek, 1400 .release = seq_release_net, 1401 }; 1402 1403 1404 static int __net_init arp_net_init(struct net *net) 1405 { 1406 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops)) 1407 return -ENOMEM; 1408 return 0; 1409 } 1410 1411 static void __net_exit arp_net_exit(struct net *net) 1412 { 1413 remove_proc_entry("arp", net->proc_net); 1414 } 1415 1416 static struct pernet_operations arp_net_ops = { 1417 .init = arp_net_init, 1418 .exit = arp_net_exit, 1419 }; 1420 1421 static int __init arp_proc_init(void) 1422 { 1423 return register_pernet_subsys(&arp_net_ops); 1424 } 1425 1426 #else /* CONFIG_PROC_FS */ 1427 1428 static int __init arp_proc_init(void) 1429 { 1430 return 0; 1431 } 1432 1433 #endif /* CONFIG_PROC_FS */ 1434