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 bool is_garp = false; 736 737 /* arp_rcv below verifies the ARP header and verifies the device 738 * is ARP'able. 739 */ 740 741 if (in_dev == NULL) 742 goto out; 743 744 arp = arp_hdr(skb); 745 746 switch (dev_type) { 747 default: 748 if (arp->ar_pro != htons(ETH_P_IP) || 749 htons(dev_type) != arp->ar_hrd) 750 goto out; 751 break; 752 case ARPHRD_ETHER: 753 case ARPHRD_FDDI: 754 case ARPHRD_IEEE802: 755 /* 756 * ETHERNET, and Fibre Channel (which are IEEE 802 757 * devices, according to RFC 2625) devices will accept ARP 758 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 759 * This is the case also of FDDI, where the RFC 1390 says that 760 * FDDI devices should accept ARP hardware of (1) Ethernet, 761 * however, to be more robust, we'll accept both 1 (Ethernet) 762 * or 6 (IEEE 802.2) 763 */ 764 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 765 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 766 arp->ar_pro != htons(ETH_P_IP)) 767 goto out; 768 break; 769 case ARPHRD_AX25: 770 if (arp->ar_pro != htons(AX25_P_IP) || 771 arp->ar_hrd != htons(ARPHRD_AX25)) 772 goto out; 773 break; 774 case ARPHRD_NETROM: 775 if (arp->ar_pro != htons(AX25_P_IP) || 776 arp->ar_hrd != htons(ARPHRD_NETROM)) 777 goto out; 778 break; 779 } 780 781 /* Understand only these message types */ 782 783 if (arp->ar_op != htons(ARPOP_REPLY) && 784 arp->ar_op != htons(ARPOP_REQUEST)) 785 goto out; 786 787 /* 788 * Extract fields 789 */ 790 arp_ptr = (unsigned char *)(arp + 1); 791 sha = arp_ptr; 792 arp_ptr += dev->addr_len; 793 memcpy(&sip, arp_ptr, 4); 794 arp_ptr += 4; 795 switch (dev_type) { 796 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 797 case ARPHRD_IEEE1394: 798 break; 799 #endif 800 default: 801 arp_ptr += dev->addr_len; 802 } 803 memcpy(&tip, arp_ptr, 4); 804 /* 805 * Check for bad requests for 127.x.x.x and requests for multicast 806 * addresses. If this is one such, delete it. 807 */ 808 if (ipv4_is_multicast(tip) || 809 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) 810 goto out; 811 812 /* 813 * Special case: We must set Frame Relay source Q.922 address 814 */ 815 if (dev_type == ARPHRD_DLCI) 816 sha = dev->broadcast; 817 818 /* 819 * Process entry. The idea here is we want to send a reply if it is a 820 * request for us or if it is a request for someone else that we hold 821 * a proxy for. We want to add an entry to our cache if it is a reply 822 * to us or if it is a request for our address. 823 * (The assumption for this last is that if someone is requesting our 824 * address, they are probably intending to talk to us, so it saves time 825 * if we cache their address. Their address is also probably not in 826 * our cache, since ours is not in their cache.) 827 * 828 * Putting this another way, we only care about replies if they are to 829 * us, in which case we add them to the cache. For requests, we care 830 * about those for us and those for our proxies. We reply to both, 831 * and in the case of requests for us we add the requester to the arp 832 * cache. 833 */ 834 835 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 836 if (sip == 0) { 837 if (arp->ar_op == htons(ARPOP_REQUEST) && 838 inet_addr_type(net, tip) == RTN_LOCAL && 839 !arp_ignore(in_dev, sip, tip)) 840 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, 841 dev->dev_addr, sha); 842 goto out; 843 } 844 845 if (arp->ar_op == htons(ARPOP_REQUEST) && 846 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 847 848 rt = skb_rtable(skb); 849 addr_type = rt->rt_type; 850 851 if (addr_type == RTN_LOCAL) { 852 int dont_send; 853 854 dont_send = arp_ignore(in_dev, sip, tip); 855 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 856 dont_send = arp_filter(sip, tip, dev); 857 if (!dont_send) { 858 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 859 if (n) { 860 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 861 dev, tip, sha, dev->dev_addr, 862 sha); 863 neigh_release(n); 864 } 865 } 866 goto out; 867 } else if (IN_DEV_FORWARD(in_dev)) { 868 if (addr_type == RTN_UNICAST && 869 (arp_fwd_proxy(in_dev, dev, rt) || 870 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 871 (rt->dst.dev != dev && 872 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 873 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 874 if (n) 875 neigh_release(n); 876 877 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 878 skb->pkt_type == PACKET_HOST || 879 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { 880 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, 881 dev, tip, sha, dev->dev_addr, 882 sha); 883 } else { 884 pneigh_enqueue(&arp_tbl, 885 in_dev->arp_parms, skb); 886 return 0; 887 } 888 goto out; 889 } 890 } 891 } 892 893 /* Update our ARP tables */ 894 895 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 896 897 if (IN_DEV_ARP_ACCEPT(in_dev)) { 898 /* Unsolicited ARP is not accepted by default. 899 It is possible, that this option should be enabled for some 900 devices (strip is candidate) 901 */ 902 is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip && 903 inet_addr_type(net, sip) == RTN_UNICAST; 904 905 if (n == NULL && 906 ((arp->ar_op == htons(ARPOP_REPLY) && 907 inet_addr_type(net, sip) == RTN_UNICAST) || is_garp)) 908 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 909 } 910 911 if (n) { 912 int state = NUD_REACHABLE; 913 int override; 914 915 /* If several different ARP replies follows back-to-back, 916 use the FIRST one. It is possible, if several proxy 917 agents are active. Taking the first reply prevents 918 arp trashing and chooses the fastest router. 919 */ 920 override = time_after(jiffies, 921 n->updated + 922 NEIGH_VAR(n->parms, LOCKTIME)) || 923 is_garp; 924 925 /* Broadcast replies and request packets 926 do not assert neighbour reachability. 927 */ 928 if (arp->ar_op != htons(ARPOP_REPLY) || 929 skb->pkt_type != PACKET_HOST) 930 state = NUD_STALE; 931 neigh_update(n, sha, state, 932 override ? NEIGH_UPDATE_F_OVERRIDE : 0); 933 neigh_release(n); 934 } 935 936 out: 937 consume_skb(skb); 938 return 0; 939 } 940 941 static void parp_redo(struct sk_buff *skb) 942 { 943 arp_process(skb); 944 } 945 946 947 /* 948 * Receive an arp request from the device layer. 949 */ 950 951 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 952 struct packet_type *pt, struct net_device *orig_dev) 953 { 954 const struct arphdr *arp; 955 956 if (dev->flags & IFF_NOARP || 957 skb->pkt_type == PACKET_OTHERHOST || 958 skb->pkt_type == PACKET_LOOPBACK) 959 goto freeskb; 960 961 skb = skb_share_check(skb, GFP_ATOMIC); 962 if (!skb) 963 goto out_of_mem; 964 965 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 966 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 967 goto freeskb; 968 969 arp = arp_hdr(skb); 970 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 971 goto freeskb; 972 973 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 974 975 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); 976 977 freeskb: 978 kfree_skb(skb); 979 out_of_mem: 980 return 0; 981 } 982 983 /* 984 * User level interface (ioctl) 985 */ 986 987 /* 988 * Set (create) an ARP cache entry. 989 */ 990 991 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 992 { 993 if (dev == NULL) { 994 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 995 return 0; 996 } 997 if (__in_dev_get_rtnl(dev)) { 998 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 999 return 0; 1000 } 1001 return -ENXIO; 1002 } 1003 1004 static int arp_req_set_public(struct net *net, struct arpreq *r, 1005 struct net_device *dev) 1006 { 1007 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1008 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1009 1010 if (mask && mask != htonl(0xFFFFFFFF)) 1011 return -EINVAL; 1012 if (!dev && (r->arp_flags & ATF_COM)) { 1013 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 1014 r->arp_ha.sa_data); 1015 if (!dev) 1016 return -ENODEV; 1017 } 1018 if (mask) { 1019 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL) 1020 return -ENOBUFS; 1021 return 0; 1022 } 1023 1024 return arp_req_set_proxy(net, dev, 1); 1025 } 1026 1027 static int arp_req_set(struct net *net, struct arpreq *r, 1028 struct net_device *dev) 1029 { 1030 __be32 ip; 1031 struct neighbour *neigh; 1032 int err; 1033 1034 if (r->arp_flags & ATF_PUBL) 1035 return arp_req_set_public(net, r, dev); 1036 1037 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1038 if (r->arp_flags & ATF_PERM) 1039 r->arp_flags |= ATF_COM; 1040 if (dev == NULL) { 1041 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1042 1043 if (IS_ERR(rt)) 1044 return PTR_ERR(rt); 1045 dev = rt->dst.dev; 1046 ip_rt_put(rt); 1047 if (!dev) 1048 return -EINVAL; 1049 } 1050 switch (dev->type) { 1051 #if IS_ENABLED(CONFIG_FDDI) 1052 case ARPHRD_FDDI: 1053 /* 1054 * According to RFC 1390, FDDI devices should accept ARP 1055 * hardware types of 1 (Ethernet). However, to be more 1056 * robust, we'll accept hardware types of either 1 (Ethernet) 1057 * or 6 (IEEE 802.2). 1058 */ 1059 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1060 r->arp_ha.sa_family != ARPHRD_ETHER && 1061 r->arp_ha.sa_family != ARPHRD_IEEE802) 1062 return -EINVAL; 1063 break; 1064 #endif 1065 default: 1066 if (r->arp_ha.sa_family != dev->type) 1067 return -EINVAL; 1068 break; 1069 } 1070 1071 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1072 err = PTR_ERR(neigh); 1073 if (!IS_ERR(neigh)) { 1074 unsigned int state = NUD_STALE; 1075 if (r->arp_flags & ATF_PERM) 1076 state = NUD_PERMANENT; 1077 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1078 r->arp_ha.sa_data : NULL, state, 1079 NEIGH_UPDATE_F_OVERRIDE | 1080 NEIGH_UPDATE_F_ADMIN); 1081 neigh_release(neigh); 1082 } 1083 return err; 1084 } 1085 1086 static unsigned int arp_state_to_flags(struct neighbour *neigh) 1087 { 1088 if (neigh->nud_state&NUD_PERMANENT) 1089 return ATF_PERM | ATF_COM; 1090 else if (neigh->nud_state&NUD_VALID) 1091 return ATF_COM; 1092 else 1093 return 0; 1094 } 1095 1096 /* 1097 * Get an ARP cache entry. 1098 */ 1099 1100 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1101 { 1102 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1103 struct neighbour *neigh; 1104 int err = -ENXIO; 1105 1106 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1107 if (neigh) { 1108 read_lock_bh(&neigh->lock); 1109 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1110 r->arp_flags = arp_state_to_flags(neigh); 1111 read_unlock_bh(&neigh->lock); 1112 r->arp_ha.sa_family = dev->type; 1113 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1114 neigh_release(neigh); 1115 err = 0; 1116 } 1117 return err; 1118 } 1119 1120 static int arp_invalidate(struct net_device *dev, __be32 ip) 1121 { 1122 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1123 int err = -ENXIO; 1124 1125 if (neigh) { 1126 if (neigh->nud_state & ~NUD_NOARP) 1127 err = neigh_update(neigh, NULL, NUD_FAILED, 1128 NEIGH_UPDATE_F_OVERRIDE| 1129 NEIGH_UPDATE_F_ADMIN); 1130 neigh_release(neigh); 1131 } 1132 1133 return err; 1134 } 1135 1136 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1137 struct net_device *dev) 1138 { 1139 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1140 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1141 1142 if (mask == htonl(0xFFFFFFFF)) 1143 return pneigh_delete(&arp_tbl, net, &ip, dev); 1144 1145 if (mask) 1146 return -EINVAL; 1147 1148 return arp_req_set_proxy(net, dev, 0); 1149 } 1150 1151 static int arp_req_delete(struct net *net, struct arpreq *r, 1152 struct net_device *dev) 1153 { 1154 __be32 ip; 1155 1156 if (r->arp_flags & ATF_PUBL) 1157 return arp_req_delete_public(net, r, dev); 1158 1159 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1160 if (dev == NULL) { 1161 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1162 if (IS_ERR(rt)) 1163 return PTR_ERR(rt); 1164 dev = rt->dst.dev; 1165 ip_rt_put(rt); 1166 if (!dev) 1167 return -EINVAL; 1168 } 1169 return arp_invalidate(dev, ip); 1170 } 1171 1172 /* 1173 * Handle an ARP layer I/O control request. 1174 */ 1175 1176 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1177 { 1178 int err; 1179 struct arpreq r; 1180 struct net_device *dev = NULL; 1181 1182 switch (cmd) { 1183 case SIOCDARP: 1184 case SIOCSARP: 1185 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1186 return -EPERM; 1187 case SIOCGARP: 1188 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1189 if (err) 1190 return -EFAULT; 1191 break; 1192 default: 1193 return -EINVAL; 1194 } 1195 1196 if (r.arp_pa.sa_family != AF_INET) 1197 return -EPFNOSUPPORT; 1198 1199 if (!(r.arp_flags & ATF_PUBL) && 1200 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1201 return -EINVAL; 1202 if (!(r.arp_flags & ATF_NETMASK)) 1203 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1204 htonl(0xFFFFFFFFUL); 1205 rtnl_lock(); 1206 if (r.arp_dev[0]) { 1207 err = -ENODEV; 1208 dev = __dev_get_by_name(net, r.arp_dev); 1209 if (dev == NULL) 1210 goto out; 1211 1212 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1213 if (!r.arp_ha.sa_family) 1214 r.arp_ha.sa_family = dev->type; 1215 err = -EINVAL; 1216 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1217 goto out; 1218 } else if (cmd == SIOCGARP) { 1219 err = -ENODEV; 1220 goto out; 1221 } 1222 1223 switch (cmd) { 1224 case SIOCDARP: 1225 err = arp_req_delete(net, &r, dev); 1226 break; 1227 case SIOCSARP: 1228 err = arp_req_set(net, &r, dev); 1229 break; 1230 case SIOCGARP: 1231 err = arp_req_get(&r, dev); 1232 break; 1233 } 1234 out: 1235 rtnl_unlock(); 1236 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1237 err = -EFAULT; 1238 return err; 1239 } 1240 1241 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1242 void *ptr) 1243 { 1244 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1245 struct netdev_notifier_change_info *change_info; 1246 1247 switch (event) { 1248 case NETDEV_CHANGEADDR: 1249 neigh_changeaddr(&arp_tbl, dev); 1250 rt_cache_flush(dev_net(dev)); 1251 break; 1252 case NETDEV_CHANGE: 1253 change_info = ptr; 1254 if (change_info->flags_changed & IFF_NOARP) 1255 neigh_changeaddr(&arp_tbl, dev); 1256 break; 1257 default: 1258 break; 1259 } 1260 1261 return NOTIFY_DONE; 1262 } 1263 1264 static struct notifier_block arp_netdev_notifier = { 1265 .notifier_call = arp_netdev_event, 1266 }; 1267 1268 /* Note, that it is not on notifier chain. 1269 It is necessary, that this routine was called after route cache will be 1270 flushed. 1271 */ 1272 void arp_ifdown(struct net_device *dev) 1273 { 1274 neigh_ifdown(&arp_tbl, dev); 1275 } 1276 1277 1278 /* 1279 * Called once on startup. 1280 */ 1281 1282 static struct packet_type arp_packet_type __read_mostly = { 1283 .type = cpu_to_be16(ETH_P_ARP), 1284 .func = arp_rcv, 1285 }; 1286 1287 static int arp_proc_init(void); 1288 1289 void __init arp_init(void) 1290 { 1291 neigh_table_init(&arp_tbl); 1292 1293 dev_add_pack(&arp_packet_type); 1294 arp_proc_init(); 1295 #ifdef CONFIG_SYSCTL 1296 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL); 1297 #endif 1298 register_netdevice_notifier(&arp_netdev_notifier); 1299 } 1300 1301 #ifdef CONFIG_PROC_FS 1302 #if IS_ENABLED(CONFIG_AX25) 1303 1304 /* ------------------------------------------------------------------------ */ 1305 /* 1306 * ax25 -> ASCII conversion 1307 */ 1308 static char *ax2asc2(ax25_address *a, char *buf) 1309 { 1310 char c, *s; 1311 int n; 1312 1313 for (n = 0, s = buf; n < 6; n++) { 1314 c = (a->ax25_call[n] >> 1) & 0x7F; 1315 1316 if (c != ' ') 1317 *s++ = c; 1318 } 1319 1320 *s++ = '-'; 1321 n = (a->ax25_call[6] >> 1) & 0x0F; 1322 if (n > 9) { 1323 *s++ = '1'; 1324 n -= 10; 1325 } 1326 1327 *s++ = n + '0'; 1328 *s++ = '\0'; 1329 1330 if (*buf == '\0' || *buf == '-') 1331 return "*"; 1332 1333 return buf; 1334 } 1335 #endif /* CONFIG_AX25 */ 1336 1337 #define HBUFFERLEN 30 1338 1339 static void arp_format_neigh_entry(struct seq_file *seq, 1340 struct neighbour *n) 1341 { 1342 char hbuffer[HBUFFERLEN]; 1343 int k, j; 1344 char tbuf[16]; 1345 struct net_device *dev = n->dev; 1346 int hatype = dev->type; 1347 1348 read_lock(&n->lock); 1349 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1350 #if IS_ENABLED(CONFIG_AX25) 1351 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1352 ax2asc2((ax25_address *)n->ha, hbuffer); 1353 else { 1354 #endif 1355 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1356 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1357 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1358 hbuffer[k++] = ':'; 1359 } 1360 if (k != 0) 1361 --k; 1362 hbuffer[k] = 0; 1363 #if IS_ENABLED(CONFIG_AX25) 1364 } 1365 #endif 1366 sprintf(tbuf, "%pI4", n->primary_key); 1367 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1368 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1369 read_unlock(&n->lock); 1370 } 1371 1372 static void arp_format_pneigh_entry(struct seq_file *seq, 1373 struct pneigh_entry *n) 1374 { 1375 struct net_device *dev = n->dev; 1376 int hatype = dev ? dev->type : 0; 1377 char tbuf[16]; 1378 1379 sprintf(tbuf, "%pI4", n->key); 1380 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1381 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1382 dev ? dev->name : "*"); 1383 } 1384 1385 static int arp_seq_show(struct seq_file *seq, void *v) 1386 { 1387 if (v == SEQ_START_TOKEN) { 1388 seq_puts(seq, "IP address HW type Flags " 1389 "HW address Mask Device\n"); 1390 } else { 1391 struct neigh_seq_state *state = seq->private; 1392 1393 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1394 arp_format_pneigh_entry(seq, v); 1395 else 1396 arp_format_neigh_entry(seq, v); 1397 } 1398 1399 return 0; 1400 } 1401 1402 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1403 { 1404 /* Don't want to confuse "arp -a" w/ magic entries, 1405 * so we tell the generic iterator to skip NUD_NOARP. 1406 */ 1407 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1408 } 1409 1410 /* ------------------------------------------------------------------------ */ 1411 1412 static const struct seq_operations arp_seq_ops = { 1413 .start = arp_seq_start, 1414 .next = neigh_seq_next, 1415 .stop = neigh_seq_stop, 1416 .show = arp_seq_show, 1417 }; 1418 1419 static int arp_seq_open(struct inode *inode, struct file *file) 1420 { 1421 return seq_open_net(inode, file, &arp_seq_ops, 1422 sizeof(struct neigh_seq_state)); 1423 } 1424 1425 static const struct file_operations arp_seq_fops = { 1426 .owner = THIS_MODULE, 1427 .open = arp_seq_open, 1428 .read = seq_read, 1429 .llseek = seq_lseek, 1430 .release = seq_release_net, 1431 }; 1432 1433 1434 static int __net_init arp_net_init(struct net *net) 1435 { 1436 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops)) 1437 return -ENOMEM; 1438 return 0; 1439 } 1440 1441 static void __net_exit arp_net_exit(struct net *net) 1442 { 1443 remove_proc_entry("arp", net->proc_net); 1444 } 1445 1446 static struct pernet_operations arp_net_ops = { 1447 .init = arp_net_init, 1448 .exit = arp_net_exit, 1449 }; 1450 1451 static int __init arp_proc_init(void) 1452 { 1453 return register_pernet_subsys(&arp_net_ops); 1454 } 1455 1456 #else /* CONFIG_PROC_FS */ 1457 1458 static int __init arp_proc_init(void) 1459 { 1460 return 0; 1461 } 1462 1463 #endif /* CONFIG_PROC_FS */ 1464