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] = SK_WMEM_MAX, 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; 227 struct net_device *dev = neigh->dev; 228 struct in_device *in_dev; 229 struct neigh_parms *parms; 230 u32 inaddr_any = INADDR_ANY; 231 232 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) 233 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len); 234 235 addr = *(__be32 *)neigh->primary_key; 236 rcu_read_lock(); 237 in_dev = __in_dev_get_rcu(dev); 238 if (!in_dev) { 239 rcu_read_unlock(); 240 return -EINVAL; 241 } 242 243 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr); 244 245 parms = in_dev->arp_parms; 246 __neigh_parms_put(neigh->parms); 247 neigh->parms = neigh_parms_clone(parms); 248 rcu_read_unlock(); 249 250 if (!dev->header_ops) { 251 neigh->nud_state = NUD_NOARP; 252 neigh->ops = &arp_direct_ops; 253 neigh->output = neigh_direct_output; 254 } else { 255 /* Good devices (checked by reading texts, but only Ethernet is 256 tested) 257 258 ARPHRD_ETHER: (ethernet, apfddi) 259 ARPHRD_FDDI: (fddi) 260 ARPHRD_IEEE802: (tr) 261 ARPHRD_METRICOM: (strip) 262 ARPHRD_ARCNET: 263 etc. etc. etc. 264 265 ARPHRD_IPDDP will also work, if author repairs it. 266 I did not it, because this driver does not work even 267 in old paradigm. 268 */ 269 270 if (neigh->type == RTN_MULTICAST) { 271 neigh->nud_state = NUD_NOARP; 272 arp_mc_map(addr, neigh->ha, dev, 1); 273 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 274 neigh->nud_state = NUD_NOARP; 275 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 276 } else if (neigh->type == RTN_BROADCAST || 277 (dev->flags & IFF_POINTOPOINT)) { 278 neigh->nud_state = NUD_NOARP; 279 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 280 } 281 282 if (dev->header_ops->cache) 283 neigh->ops = &arp_hh_ops; 284 else 285 neigh->ops = &arp_generic_ops; 286 287 if (neigh->nud_state & NUD_VALID) 288 neigh->output = neigh->ops->connected_output; 289 else 290 neigh->output = neigh->ops->output; 291 } 292 return 0; 293 } 294 295 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 296 { 297 dst_link_failure(skb); 298 kfree_skb(skb); 299 } 300 301 /* Create and send an arp packet. */ 302 static void arp_send_dst(int type, int ptype, __be32 dest_ip, 303 struct net_device *dev, __be32 src_ip, 304 const unsigned char *dest_hw, 305 const unsigned char *src_hw, 306 const unsigned char *target_hw, 307 struct dst_entry *dst) 308 { 309 struct sk_buff *skb; 310 311 /* arp on this interface. */ 312 if (dev->flags & IFF_NOARP) 313 return; 314 315 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 316 dest_hw, src_hw, target_hw); 317 if (!skb) 318 return; 319 320 skb_dst_set(skb, dst_clone(dst)); 321 arp_xmit(skb); 322 } 323 324 void arp_send(int type, int ptype, __be32 dest_ip, 325 struct net_device *dev, __be32 src_ip, 326 const unsigned char *dest_hw, const unsigned char *src_hw, 327 const unsigned char *target_hw) 328 { 329 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw, 330 target_hw, NULL); 331 } 332 EXPORT_SYMBOL(arp_send); 333 334 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 335 { 336 __be32 saddr = 0; 337 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL; 338 struct net_device *dev = neigh->dev; 339 __be32 target = *(__be32 *)neigh->primary_key; 340 int probes = atomic_read(&neigh->probes); 341 struct in_device *in_dev; 342 struct dst_entry *dst = NULL; 343 344 rcu_read_lock(); 345 in_dev = __in_dev_get_rcu(dev); 346 if (!in_dev) { 347 rcu_read_unlock(); 348 return; 349 } 350 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 351 default: 352 case 0: /* By default announce any local IP */ 353 if (skb && inet_addr_type_dev_table(dev_net(dev), dev, 354 ip_hdr(skb)->saddr) == RTN_LOCAL) 355 saddr = ip_hdr(skb)->saddr; 356 break; 357 case 1: /* Restrict announcements of saddr in same subnet */ 358 if (!skb) 359 break; 360 saddr = ip_hdr(skb)->saddr; 361 if (inet_addr_type_dev_table(dev_net(dev), dev, 362 saddr) == RTN_LOCAL) { 363 /* saddr should be known to target */ 364 if (inet_addr_onlink(in_dev, target, saddr)) 365 break; 366 } 367 saddr = 0; 368 break; 369 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 370 break; 371 } 372 rcu_read_unlock(); 373 374 if (!saddr) 375 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 376 377 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); 378 if (probes < 0) { 379 if (!(neigh->nud_state & NUD_VALID)) 380 pr_debug("trying to ucast probe in NUD_INVALID\n"); 381 neigh_ha_snapshot(dst_ha, neigh, dev); 382 dst_hw = dst_ha; 383 } else { 384 probes -= NEIGH_VAR(neigh->parms, APP_PROBES); 385 if (probes < 0) { 386 neigh_app_ns(neigh); 387 return; 388 } 389 } 390 391 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE)) 392 dst = skb_dst(skb); 393 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 394 dst_hw, dev->dev_addr, NULL, dst); 395 } 396 397 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 398 { 399 struct net *net = dev_net(in_dev->dev); 400 int scope; 401 402 switch (IN_DEV_ARP_IGNORE(in_dev)) { 403 case 0: /* Reply, the tip is already validated */ 404 return 0; 405 case 1: /* Reply only if tip is configured on the incoming interface */ 406 sip = 0; 407 scope = RT_SCOPE_HOST; 408 break; 409 case 2: /* 410 * Reply only if tip is configured on the incoming interface 411 * and is in same subnet as sip 412 */ 413 scope = RT_SCOPE_HOST; 414 break; 415 case 3: /* Do not reply for scope host addresses */ 416 sip = 0; 417 scope = RT_SCOPE_LINK; 418 in_dev = NULL; 419 break; 420 case 4: /* Reserved */ 421 case 5: 422 case 6: 423 case 7: 424 return 0; 425 case 8: /* Do not reply */ 426 return 1; 427 default: 428 return 0; 429 } 430 return !inet_confirm_addr(net, in_dev, sip, tip, scope); 431 } 432 433 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 434 { 435 struct rtable *rt; 436 int flag = 0; 437 /*unsigned long now; */ 438 struct net *net = dev_net(dev); 439 440 rt = ip_route_output(net, sip, tip, 0, 0); 441 if (IS_ERR(rt)) 442 return 1; 443 if (rt->dst.dev != dev) { 444 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER); 445 flag = 1; 446 } 447 ip_rt_put(rt); 448 return flag; 449 } 450 451 /* 452 * Check if we can use proxy ARP for this path 453 */ 454 static inline int arp_fwd_proxy(struct in_device *in_dev, 455 struct net_device *dev, struct rtable *rt) 456 { 457 struct in_device *out_dev; 458 int imi, omi = -1; 459 460 if (rt->dst.dev == dev) 461 return 0; 462 463 if (!IN_DEV_PROXY_ARP(in_dev)) 464 return 0; 465 imi = IN_DEV_MEDIUM_ID(in_dev); 466 if (imi == 0) 467 return 1; 468 if (imi == -1) 469 return 0; 470 471 /* place to check for proxy_arp for routes */ 472 473 out_dev = __in_dev_get_rcu(rt->dst.dev); 474 if (out_dev) 475 omi = IN_DEV_MEDIUM_ID(out_dev); 476 477 return omi != imi && omi != -1; 478 } 479 480 /* 481 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 482 * 483 * RFC3069 supports proxy arp replies back to the same interface. This 484 * is done to support (ethernet) switch features, like RFC 3069, where 485 * the individual ports are not allowed to communicate with each 486 * other, BUT they are allowed to talk to the upstream router. As 487 * described in RFC 3069, it is possible to allow these hosts to 488 * communicate through the upstream router, by proxy_arp'ing. 489 * 490 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 491 * 492 * This technology is known by different names: 493 * In RFC 3069 it is called VLAN Aggregation. 494 * Cisco and Allied Telesyn call it Private VLAN. 495 * Hewlett-Packard call it Source-Port filtering or port-isolation. 496 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 497 * 498 */ 499 static inline int arp_fwd_pvlan(struct in_device *in_dev, 500 struct net_device *dev, struct rtable *rt, 501 __be32 sip, __be32 tip) 502 { 503 /* Private VLAN is only concerned about the same ethernet segment */ 504 if (rt->dst.dev != dev) 505 return 0; 506 507 /* Don't reply on self probes (often done by windowz boxes)*/ 508 if (sip == tip) 509 return 0; 510 511 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 512 return 1; 513 else 514 return 0; 515 } 516 517 /* 518 * Interface to link layer: send routine and receive handler. 519 */ 520 521 /* 522 * Create an arp packet. If dest_hw is not set, we create a broadcast 523 * message. 524 */ 525 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 526 struct net_device *dev, __be32 src_ip, 527 const unsigned char *dest_hw, 528 const unsigned char *src_hw, 529 const unsigned char *target_hw) 530 { 531 struct sk_buff *skb; 532 struct arphdr *arp; 533 unsigned char *arp_ptr; 534 int hlen = LL_RESERVED_SPACE(dev); 535 int tlen = dev->needed_tailroom; 536 537 /* 538 * Allocate a buffer 539 */ 540 541 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 542 if (!skb) 543 return NULL; 544 545 skb_reserve(skb, hlen); 546 skb_reset_network_header(skb); 547 arp = skb_put(skb, arp_hdr_len(dev)); 548 skb->dev = dev; 549 skb->protocol = htons(ETH_P_ARP); 550 if (!src_hw) 551 src_hw = dev->dev_addr; 552 if (!dest_hw) 553 dest_hw = dev->broadcast; 554 555 /* 556 * Fill the device header for the ARP frame 557 */ 558 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 559 goto out; 560 561 /* 562 * Fill out the arp protocol part. 563 * 564 * The arp hardware type should match the device type, except for FDDI, 565 * which (according to RFC 1390) should always equal 1 (Ethernet). 566 */ 567 /* 568 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 569 * DIX code for the protocol. Make these device structure fields. 570 */ 571 switch (dev->type) { 572 default: 573 arp->ar_hrd = htons(dev->type); 574 arp->ar_pro = htons(ETH_P_IP); 575 break; 576 577 #if IS_ENABLED(CONFIG_AX25) 578 case ARPHRD_AX25: 579 arp->ar_hrd = htons(ARPHRD_AX25); 580 arp->ar_pro = htons(AX25_P_IP); 581 break; 582 583 #if IS_ENABLED(CONFIG_NETROM) 584 case ARPHRD_NETROM: 585 arp->ar_hrd = htons(ARPHRD_NETROM); 586 arp->ar_pro = htons(AX25_P_IP); 587 break; 588 #endif 589 #endif 590 591 #if IS_ENABLED(CONFIG_FDDI) 592 case ARPHRD_FDDI: 593 arp->ar_hrd = htons(ARPHRD_ETHER); 594 arp->ar_pro = htons(ETH_P_IP); 595 break; 596 #endif 597 } 598 599 arp->ar_hln = dev->addr_len; 600 arp->ar_pln = 4; 601 arp->ar_op = htons(type); 602 603 arp_ptr = (unsigned char *)(arp + 1); 604 605 memcpy(arp_ptr, src_hw, dev->addr_len); 606 arp_ptr += dev->addr_len; 607 memcpy(arp_ptr, &src_ip, 4); 608 arp_ptr += 4; 609 610 switch (dev->type) { 611 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 612 case ARPHRD_IEEE1394: 613 break; 614 #endif 615 default: 616 if (target_hw) 617 memcpy(arp_ptr, target_hw, dev->addr_len); 618 else 619 memset(arp_ptr, 0, dev->addr_len); 620 arp_ptr += dev->addr_len; 621 } 622 memcpy(arp_ptr, &dest_ip, 4); 623 624 return skb; 625 626 out: 627 kfree_skb(skb); 628 return NULL; 629 } 630 EXPORT_SYMBOL(arp_create); 631 632 static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 633 { 634 return dev_queue_xmit(skb); 635 } 636 637 /* 638 * Send an arp packet. 639 */ 640 void arp_xmit(struct sk_buff *skb) 641 { 642 /* Send it off, maybe filter it using firewalling first. */ 643 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, 644 dev_net(skb->dev), NULL, skb, NULL, skb->dev, 645 arp_xmit_finish); 646 } 647 EXPORT_SYMBOL(arp_xmit); 648 649 static bool arp_is_garp(struct net *net, struct net_device *dev, 650 int *addr_type, __be16 ar_op, 651 __be32 sip, __be32 tip, 652 unsigned char *sha, unsigned char *tha) 653 { 654 bool is_garp = tip == sip; 655 656 /* Gratuitous ARP _replies_ also require target hwaddr to be 657 * the same as source. 658 */ 659 if (is_garp && ar_op == htons(ARPOP_REPLY)) 660 is_garp = 661 /* IPv4 over IEEE 1394 doesn't provide target 662 * hardware address field in its ARP payload. 663 */ 664 tha && 665 !memcmp(tha, sha, dev->addr_len); 666 667 if (is_garp) { 668 *addr_type = inet_addr_type_dev_table(net, dev, sip); 669 if (*addr_type != RTN_UNICAST) 670 is_garp = false; 671 } 672 return is_garp; 673 } 674 675 /* 676 * Process an arp request. 677 */ 678 679 static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb) 680 { 681 struct net_device *dev = skb->dev; 682 struct in_device *in_dev = __in_dev_get_rcu(dev); 683 struct arphdr *arp; 684 unsigned char *arp_ptr; 685 struct rtable *rt; 686 unsigned char *sha; 687 unsigned char *tha = NULL; 688 __be32 sip, tip; 689 u16 dev_type = dev->type; 690 int addr_type; 691 struct neighbour *n; 692 struct dst_entry *reply_dst = NULL; 693 bool is_garp = false; 694 695 /* arp_rcv below verifies the ARP header and verifies the device 696 * is ARP'able. 697 */ 698 699 if (!in_dev) 700 goto out_free_skb; 701 702 arp = arp_hdr(skb); 703 704 switch (dev_type) { 705 default: 706 if (arp->ar_pro != htons(ETH_P_IP) || 707 htons(dev_type) != arp->ar_hrd) 708 goto out_free_skb; 709 break; 710 case ARPHRD_ETHER: 711 case ARPHRD_FDDI: 712 case ARPHRD_IEEE802: 713 /* 714 * ETHERNET, and Fibre Channel (which are IEEE 802 715 * devices, according to RFC 2625) devices will accept ARP 716 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 717 * This is the case also of FDDI, where the RFC 1390 says that 718 * FDDI devices should accept ARP hardware of (1) Ethernet, 719 * however, to be more robust, we'll accept both 1 (Ethernet) 720 * or 6 (IEEE 802.2) 721 */ 722 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 723 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 724 arp->ar_pro != htons(ETH_P_IP)) 725 goto out_free_skb; 726 break; 727 case ARPHRD_AX25: 728 if (arp->ar_pro != htons(AX25_P_IP) || 729 arp->ar_hrd != htons(ARPHRD_AX25)) 730 goto out_free_skb; 731 break; 732 case ARPHRD_NETROM: 733 if (arp->ar_pro != htons(AX25_P_IP) || 734 arp->ar_hrd != htons(ARPHRD_NETROM)) 735 goto out_free_skb; 736 break; 737 } 738 739 /* Understand only these message types */ 740 741 if (arp->ar_op != htons(ARPOP_REPLY) && 742 arp->ar_op != htons(ARPOP_REQUEST)) 743 goto out_free_skb; 744 745 /* 746 * Extract fields 747 */ 748 arp_ptr = (unsigned char *)(arp + 1); 749 sha = arp_ptr; 750 arp_ptr += dev->addr_len; 751 memcpy(&sip, arp_ptr, 4); 752 arp_ptr += 4; 753 switch (dev_type) { 754 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 755 case ARPHRD_IEEE1394: 756 break; 757 #endif 758 default: 759 tha = arp_ptr; 760 arp_ptr += dev->addr_len; 761 } 762 memcpy(&tip, arp_ptr, 4); 763 /* 764 * Check for bad requests for 127.x.x.x and requests for multicast 765 * addresses. If this is one such, delete it. 766 */ 767 if (ipv4_is_multicast(tip) || 768 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) 769 goto out_free_skb; 770 771 /* 772 * For some 802.11 wireless deployments (and possibly other networks), 773 * there will be an ARP proxy and gratuitous ARP frames are attacks 774 * and thus should not be accepted. 775 */ 776 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP)) 777 goto out_free_skb; 778 779 /* 780 * Special case: We must set Frame Relay source Q.922 address 781 */ 782 if (dev_type == ARPHRD_DLCI) 783 sha = dev->broadcast; 784 785 /* 786 * Process entry. The idea here is we want to send a reply if it is a 787 * request for us or if it is a request for someone else that we hold 788 * a proxy for. We want to add an entry to our cache if it is a reply 789 * to us or if it is a request for our address. 790 * (The assumption for this last is that if someone is requesting our 791 * address, they are probably intending to talk to us, so it saves time 792 * if we cache their address. Their address is also probably not in 793 * our cache, since ours is not in their cache.) 794 * 795 * Putting this another way, we only care about replies if they are to 796 * us, in which case we add them to the cache. For requests, we care 797 * about those for us and those for our proxies. We reply to both, 798 * and in the case of requests for us we add the requester to the arp 799 * cache. 800 */ 801 802 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb)) 803 reply_dst = (struct dst_entry *) 804 iptunnel_metadata_reply(skb_metadata_dst(skb), 805 GFP_ATOMIC); 806 807 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 808 if (sip == 0) { 809 if (arp->ar_op == htons(ARPOP_REQUEST) && 810 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL && 811 !arp_ignore(in_dev, sip, tip)) 812 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, 813 sha, dev->dev_addr, sha, reply_dst); 814 goto out_consume_skb; 815 } 816 817 if (arp->ar_op == htons(ARPOP_REQUEST) && 818 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 819 820 rt = skb_rtable(skb); 821 addr_type = rt->rt_type; 822 823 if (addr_type == RTN_LOCAL) { 824 int dont_send; 825 826 dont_send = arp_ignore(in_dev, sip, tip); 827 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 828 dont_send = arp_filter(sip, tip, dev); 829 if (!dont_send) { 830 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 831 if (n) { 832 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 833 sip, dev, tip, sha, 834 dev->dev_addr, sha, 835 reply_dst); 836 neigh_release(n); 837 } 838 } 839 goto out_consume_skb; 840 } else if (IN_DEV_FORWARD(in_dev)) { 841 if (addr_type == RTN_UNICAST && 842 (arp_fwd_proxy(in_dev, dev, rt) || 843 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 844 (rt->dst.dev != dev && 845 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 846 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 847 if (n) 848 neigh_release(n); 849 850 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 851 skb->pkt_type == PACKET_HOST || 852 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { 853 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 854 sip, dev, tip, sha, 855 dev->dev_addr, sha, 856 reply_dst); 857 } else { 858 pneigh_enqueue(&arp_tbl, 859 in_dev->arp_parms, skb); 860 goto out_free_dst; 861 } 862 goto out_consume_skb; 863 } 864 } 865 } 866 867 /* Update our ARP tables */ 868 869 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 870 871 addr_type = -1; 872 if (n || IN_DEV_ARP_ACCEPT(in_dev)) { 873 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op, 874 sip, tip, sha, tha); 875 } 876 877 if (IN_DEV_ARP_ACCEPT(in_dev)) { 878 /* Unsolicited ARP is not accepted by default. 879 It is possible, that this option should be enabled for some 880 devices (strip is candidate) 881 */ 882 if (!n && 883 (is_garp || 884 (arp->ar_op == htons(ARPOP_REPLY) && 885 (addr_type == RTN_UNICAST || 886 (addr_type < 0 && 887 /* postpone calculation to as late as possible */ 888 inet_addr_type_dev_table(net, dev, sip) == 889 RTN_UNICAST))))) 890 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 891 } 892 893 if (n) { 894 int state = NUD_REACHABLE; 895 int override; 896 897 /* If several different ARP replies follows back-to-back, 898 use the FIRST one. It is possible, if several proxy 899 agents are active. Taking the first reply prevents 900 arp trashing and chooses the fastest router. 901 */ 902 override = time_after(jiffies, 903 n->updated + 904 NEIGH_VAR(n->parms, LOCKTIME)) || 905 is_garp; 906 907 /* Broadcast replies and request packets 908 do not assert neighbour reachability. 909 */ 910 if (arp->ar_op != htons(ARPOP_REPLY) || 911 skb->pkt_type != PACKET_HOST) 912 state = NUD_STALE; 913 neigh_update(n, sha, state, 914 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0); 915 neigh_release(n); 916 } 917 918 out_consume_skb: 919 consume_skb(skb); 920 921 out_free_dst: 922 dst_release(reply_dst); 923 return NET_RX_SUCCESS; 924 925 out_free_skb: 926 kfree_skb(skb); 927 return NET_RX_DROP; 928 } 929 930 static void parp_redo(struct sk_buff *skb) 931 { 932 arp_process(dev_net(skb->dev), NULL, skb); 933 } 934 935 936 /* 937 * Receive an arp request from the device layer. 938 */ 939 940 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 941 struct packet_type *pt, struct net_device *orig_dev) 942 { 943 const struct arphdr *arp; 944 945 /* do not tweak dropwatch on an ARP we will ignore */ 946 if (dev->flags & IFF_NOARP || 947 skb->pkt_type == PACKET_OTHERHOST || 948 skb->pkt_type == PACKET_LOOPBACK) 949 goto consumeskb; 950 951 skb = skb_share_check(skb, GFP_ATOMIC); 952 if (!skb) 953 goto out_of_mem; 954 955 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 956 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 957 goto freeskb; 958 959 arp = arp_hdr(skb); 960 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 961 goto freeskb; 962 963 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 964 965 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, 966 dev_net(dev), NULL, skb, dev, NULL, 967 arp_process); 968 969 consumeskb: 970 consume_skb(skb); 971 return NET_RX_SUCCESS; 972 freeskb: 973 kfree_skb(skb); 974 out_of_mem: 975 return NET_RX_DROP; 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) { 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)) 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) { 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, 0); 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 if (!(neigh->nud_state & NUD_NOARP)) { 1104 read_lock_bh(&neigh->lock); 1105 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1106 r->arp_flags = arp_state_to_flags(neigh); 1107 read_unlock_bh(&neigh->lock); 1108 r->arp_ha.sa_family = dev->type; 1109 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1110 err = 0; 1111 } 1112 neigh_release(neigh); 1113 } 1114 return err; 1115 } 1116 1117 static int arp_invalidate(struct net_device *dev, __be32 ip) 1118 { 1119 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1120 int err = -ENXIO; 1121 struct neigh_table *tbl = &arp_tbl; 1122 1123 if (neigh) { 1124 if (neigh->nud_state & ~NUD_NOARP) 1125 err = neigh_update(neigh, NULL, NUD_FAILED, 1126 NEIGH_UPDATE_F_OVERRIDE| 1127 NEIGH_UPDATE_F_ADMIN, 0); 1128 write_lock_bh(&tbl->lock); 1129 neigh_release(neigh); 1130 neigh_remove_one(neigh, tbl); 1131 write_unlock_bh(&tbl->lock); 1132 } 1133 1134 return err; 1135 } 1136 1137 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1138 struct net_device *dev) 1139 { 1140 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1141 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1142 1143 if (mask == htonl(0xFFFFFFFF)) 1144 return pneigh_delete(&arp_tbl, net, &ip, dev); 1145 1146 if (mask) 1147 return -EINVAL; 1148 1149 return arp_req_set_proxy(net, dev, 0); 1150 } 1151 1152 static int arp_req_delete(struct net *net, struct arpreq *r, 1153 struct net_device *dev) 1154 { 1155 __be32 ip; 1156 1157 if (r->arp_flags & ATF_PUBL) 1158 return arp_req_delete_public(net, r, dev); 1159 1160 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1161 if (!dev) { 1162 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1163 if (IS_ERR(rt)) 1164 return PTR_ERR(rt); 1165 dev = rt->dst.dev; 1166 ip_rt_put(rt); 1167 if (!dev) 1168 return -EINVAL; 1169 } 1170 return arp_invalidate(dev, ip); 1171 } 1172 1173 /* 1174 * Handle an ARP layer I/O control request. 1175 */ 1176 1177 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1178 { 1179 int err; 1180 struct arpreq r; 1181 struct net_device *dev = NULL; 1182 1183 switch (cmd) { 1184 case SIOCDARP: 1185 case SIOCSARP: 1186 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1187 return -EPERM; 1188 /* fall through */ 1189 case SIOCGARP: 1190 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1191 if (err) 1192 return -EFAULT; 1193 break; 1194 default: 1195 return -EINVAL; 1196 } 1197 1198 if (r.arp_pa.sa_family != AF_INET) 1199 return -EPFNOSUPPORT; 1200 1201 if (!(r.arp_flags & ATF_PUBL) && 1202 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1203 return -EINVAL; 1204 if (!(r.arp_flags & ATF_NETMASK)) 1205 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1206 htonl(0xFFFFFFFFUL); 1207 rtnl_lock(); 1208 if (r.arp_dev[0]) { 1209 err = -ENODEV; 1210 dev = __dev_get_by_name(net, r.arp_dev); 1211 if (!dev) 1212 goto out; 1213 1214 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1215 if (!r.arp_ha.sa_family) 1216 r.arp_ha.sa_family = dev->type; 1217 err = -EINVAL; 1218 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1219 goto out; 1220 } else if (cmd == SIOCGARP) { 1221 err = -ENODEV; 1222 goto out; 1223 } 1224 1225 switch (cmd) { 1226 case SIOCDARP: 1227 err = arp_req_delete(net, &r, dev); 1228 break; 1229 case SIOCSARP: 1230 err = arp_req_set(net, &r, dev); 1231 break; 1232 case SIOCGARP: 1233 err = arp_req_get(&r, dev); 1234 break; 1235 } 1236 out: 1237 rtnl_unlock(); 1238 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1239 err = -EFAULT; 1240 return err; 1241 } 1242 1243 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1244 void *ptr) 1245 { 1246 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1247 struct netdev_notifier_change_info *change_info; 1248 1249 switch (event) { 1250 case NETDEV_CHANGEADDR: 1251 neigh_changeaddr(&arp_tbl, dev); 1252 rt_cache_flush(dev_net(dev)); 1253 break; 1254 case NETDEV_CHANGE: 1255 change_info = ptr; 1256 if (change_info->flags_changed & IFF_NOARP) 1257 neigh_changeaddr(&arp_tbl, dev); 1258 break; 1259 default: 1260 break; 1261 } 1262 1263 return NOTIFY_DONE; 1264 } 1265 1266 static struct notifier_block arp_netdev_notifier = { 1267 .notifier_call = arp_netdev_event, 1268 }; 1269 1270 /* Note, that it is not on notifier chain. 1271 It is necessary, that this routine was called after route cache will be 1272 flushed. 1273 */ 1274 void arp_ifdown(struct net_device *dev) 1275 { 1276 neigh_ifdown(&arp_tbl, dev); 1277 } 1278 1279 1280 /* 1281 * Called once on startup. 1282 */ 1283 1284 static struct packet_type arp_packet_type __read_mostly = { 1285 .type = cpu_to_be16(ETH_P_ARP), 1286 .func = arp_rcv, 1287 }; 1288 1289 static int arp_proc_init(void); 1290 1291 void __init arp_init(void) 1292 { 1293 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl); 1294 1295 dev_add_pack(&arp_packet_type); 1296 arp_proc_init(); 1297 #ifdef CONFIG_SYSCTL 1298 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL); 1299 #endif 1300 register_netdevice_notifier(&arp_netdev_notifier); 1301 } 1302 1303 #ifdef CONFIG_PROC_FS 1304 #if IS_ENABLED(CONFIG_AX25) 1305 1306 /* ------------------------------------------------------------------------ */ 1307 /* 1308 * ax25 -> ASCII conversion 1309 */ 1310 static void ax2asc2(ax25_address *a, char *buf) 1311 { 1312 char c, *s; 1313 int n; 1314 1315 for (n = 0, s = buf; n < 6; n++) { 1316 c = (a->ax25_call[n] >> 1) & 0x7F; 1317 1318 if (c != ' ') 1319 *s++ = c; 1320 } 1321 1322 *s++ = '-'; 1323 n = (a->ax25_call[6] >> 1) & 0x0F; 1324 if (n > 9) { 1325 *s++ = '1'; 1326 n -= 10; 1327 } 1328 1329 *s++ = n + '0'; 1330 *s++ = '\0'; 1331 1332 if (*buf == '\0' || *buf == '-') { 1333 buf[0] = '*'; 1334 buf[1] = '\0'; 1335 } 1336 } 1337 #endif /* CONFIG_AX25 */ 1338 1339 #define HBUFFERLEN 30 1340 1341 static void arp_format_neigh_entry(struct seq_file *seq, 1342 struct neighbour *n) 1343 { 1344 char hbuffer[HBUFFERLEN]; 1345 int k, j; 1346 char tbuf[16]; 1347 struct net_device *dev = n->dev; 1348 int hatype = dev->type; 1349 1350 read_lock(&n->lock); 1351 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1352 #if IS_ENABLED(CONFIG_AX25) 1353 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1354 ax2asc2((ax25_address *)n->ha, hbuffer); 1355 else { 1356 #endif 1357 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1358 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1359 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1360 hbuffer[k++] = ':'; 1361 } 1362 if (k != 0) 1363 --k; 1364 hbuffer[k] = 0; 1365 #if IS_ENABLED(CONFIG_AX25) 1366 } 1367 #endif 1368 sprintf(tbuf, "%pI4", n->primary_key); 1369 seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n", 1370 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1371 read_unlock(&n->lock); 1372 } 1373 1374 static void arp_format_pneigh_entry(struct seq_file *seq, 1375 struct pneigh_entry *n) 1376 { 1377 struct net_device *dev = n->dev; 1378 int hatype = dev ? dev->type : 0; 1379 char tbuf[16]; 1380 1381 sprintf(tbuf, "%pI4", n->key); 1382 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1383 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1384 dev ? dev->name : "*"); 1385 } 1386 1387 static int arp_seq_show(struct seq_file *seq, void *v) 1388 { 1389 if (v == SEQ_START_TOKEN) { 1390 seq_puts(seq, "IP address HW type Flags " 1391 "HW address Mask Device\n"); 1392 } else { 1393 struct neigh_seq_state *state = seq->private; 1394 1395 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1396 arp_format_pneigh_entry(seq, v); 1397 else 1398 arp_format_neigh_entry(seq, v); 1399 } 1400 1401 return 0; 1402 } 1403 1404 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1405 { 1406 /* Don't want to confuse "arp -a" w/ magic entries, 1407 * so we tell the generic iterator to skip NUD_NOARP. 1408 */ 1409 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1410 } 1411 1412 /* ------------------------------------------------------------------------ */ 1413 1414 static const struct seq_operations arp_seq_ops = { 1415 .start = arp_seq_start, 1416 .next = neigh_seq_next, 1417 .stop = neigh_seq_stop, 1418 .show = arp_seq_show, 1419 }; 1420 1421 static int arp_seq_open(struct inode *inode, struct file *file) 1422 { 1423 return seq_open_net(inode, file, &arp_seq_ops, 1424 sizeof(struct neigh_seq_state)); 1425 } 1426 1427 static const struct file_operations arp_seq_fops = { 1428 .open = arp_seq_open, 1429 .read = seq_read, 1430 .llseek = seq_lseek, 1431 .release = seq_release_net, 1432 }; 1433 1434 1435 static int __net_init arp_net_init(struct net *net) 1436 { 1437 if (!proc_create("arp", 0444, net->proc_net, &arp_seq_fops)) 1438 return -ENOMEM; 1439 return 0; 1440 } 1441 1442 static void __net_exit arp_net_exit(struct net *net) 1443 { 1444 remove_proc_entry("arp", net->proc_net); 1445 } 1446 1447 static struct pernet_operations arp_net_ops = { 1448 .init = arp_net_init, 1449 .exit = arp_net_exit, 1450 }; 1451 1452 static int __init arp_proc_init(void) 1453 { 1454 return register_pernet_subsys(&arp_net_ops); 1455 } 1456 1457 #else /* CONFIG_PROC_FS */ 1458 1459 static int __init arp_proc_init(void) 1460 { 1461 return 0; 1462 } 1463 1464 #endif /* CONFIG_PROC_FS */ 1465