1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* linux/net/ipv4/arp.c 3 * 4 * Copyright (C) 1994 by Florian La Roche 5 * 6 * This module implements the Address Resolution Protocol ARP (RFC 826), 7 * which is used to convert IP addresses (or in the future maybe other 8 * high-level addresses) into a low-level hardware address (like an Ethernet 9 * address). 10 * 11 * Fixes: 12 * Alan Cox : Removed the Ethernet assumptions in 13 * Florian's code 14 * Alan Cox : Fixed some small errors in the ARP 15 * logic 16 * Alan Cox : Allow >4K in /proc 17 * Alan Cox : Make ARP add its own protocol entry 18 * Ross Martin : Rewrote arp_rcv() and arp_get_info() 19 * Stephen Henson : Add AX25 support to arp_get_info() 20 * Alan Cox : Drop data when a device is downed. 21 * Alan Cox : Use init_timer(). 22 * Alan Cox : Double lock fixes. 23 * Martin Seine : Move the arphdr structure 24 * to if_arp.h for compatibility. 25 * with BSD based programs. 26 * Andrew Tridgell : Added ARP netmask code and 27 * re-arranged proxy handling. 28 * Alan Cox : Changed to use notifiers. 29 * Niibe Yutaka : Reply for this device or proxies only. 30 * Alan Cox : Don't proxy across hardware types! 31 * Jonathan Naylor : Added support for NET/ROM. 32 * Mike Shaver : RFC1122 checks. 33 * Jonathan Naylor : Only lookup the hardware address for 34 * the correct hardware type. 35 * Germano Caronni : Assorted subtle races. 36 * Craig Schlenter : Don't modify permanent entry 37 * during arp_rcv. 38 * Russ Nelson : Tidied up a few bits. 39 * Alexey Kuznetsov: Major changes to caching and behaviour, 40 * eg intelligent arp probing and 41 * generation 42 * of host down events. 43 * Alan Cox : Missing unlock in device events. 44 * Eckes : ARP ioctl control errors. 45 * Alexey Kuznetsov: Arp free fix. 46 * Manuel Rodriguez: Gratuitous ARP. 47 * Jonathan Layes : Added arpd support through kerneld 48 * message queue (960314) 49 * Mike Shaver : /proc/sys/net/ipv4/arp_* support 50 * Mike McLagan : Routing by source 51 * Stuart Cheshire : Metricom and grat arp fixes 52 * *** FOR 2.1 clean this up *** 53 * Lawrence V. Stefani: (08/12/96) Added FDDI support. 54 * Alan Cox : Took the AP1000 nasty FDDI hack and 55 * folded into the mainstream FDDI code. 56 * Ack spit, Linus how did you allow that 57 * one in... 58 * Jes Sorensen : Make FDDI work again in 2.1.x and 59 * clean up the APFDDI & gen. FDDI bits. 60 * Alexey Kuznetsov: new arp state machine; 61 * now it is in net/core/neighbour.c. 62 * Krzysztof Halasa: Added Frame Relay ARP support. 63 * Arnaldo C. Melo : convert /proc/net/arp to seq_file 64 * Shmulik Hen: Split arp_send to arp_create and 65 * arp_xmit so intermediate drivers like 66 * bonding can change the skb before 67 * sending (e.g. insert 8021q tag). 68 * Harald Welte : convert to make use of jenkins hash 69 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support. 70 */ 71 72 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 73 74 #include <linux/module.h> 75 #include <linux/types.h> 76 #include <linux/string.h> 77 #include <linux/kernel.h> 78 #include <linux/capability.h> 79 #include <linux/socket.h> 80 #include <linux/sockios.h> 81 #include <linux/errno.h> 82 #include <linux/in.h> 83 #include <linux/mm.h> 84 #include <linux/inet.h> 85 #include <linux/inetdevice.h> 86 #include <linux/netdevice.h> 87 #include <linux/etherdevice.h> 88 #include <linux/fddidevice.h> 89 #include <linux/if_arp.h> 90 #include <linux/skbuff.h> 91 #include <linux/proc_fs.h> 92 #include <linux/seq_file.h> 93 #include <linux/stat.h> 94 #include <linux/init.h> 95 #include <linux/net.h> 96 #include <linux/rcupdate.h> 97 #include <linux/slab.h> 98 #ifdef CONFIG_SYSCTL 99 #include <linux/sysctl.h> 100 #endif 101 102 #include <net/net_namespace.h> 103 #include <net/ip.h> 104 #include <net/icmp.h> 105 #include <net/route.h> 106 #include <net/protocol.h> 107 #include <net/tcp.h> 108 #include <net/sock.h> 109 #include <net/arp.h> 110 #include <net/ax25.h> 111 #include <net/netrom.h> 112 #include <net/dst_metadata.h> 113 #include <net/ip_tunnels.h> 114 115 #include <linux/uaccess.h> 116 117 #include <linux/netfilter_arp.h> 118 119 /* 120 * Interface to generic neighbour cache. 121 */ 122 static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); 123 static bool arp_key_eq(const struct neighbour *n, const void *pkey); 124 static int arp_constructor(struct neighbour *neigh); 125 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); 126 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); 127 static void parp_redo(struct sk_buff *skb); 128 129 static const struct neigh_ops arp_generic_ops = { 130 .family = AF_INET, 131 .solicit = arp_solicit, 132 .error_report = arp_error_report, 133 .output = neigh_resolve_output, 134 .connected_output = neigh_connected_output, 135 }; 136 137 static const struct neigh_ops arp_hh_ops = { 138 .family = AF_INET, 139 .solicit = arp_solicit, 140 .error_report = arp_error_report, 141 .output = neigh_resolve_output, 142 .connected_output = neigh_resolve_output, 143 }; 144 145 static const struct neigh_ops arp_direct_ops = { 146 .family = AF_INET, 147 .output = neigh_direct_output, 148 .connected_output = neigh_direct_output, 149 }; 150 151 struct neigh_table arp_tbl = { 152 .family = AF_INET, 153 .key_len = 4, 154 .protocol = cpu_to_be16(ETH_P_IP), 155 .hash = arp_hash, 156 .key_eq = arp_key_eq, 157 .constructor = arp_constructor, 158 .proxy_redo = parp_redo, 159 .id = "arp_cache", 160 .parms = { 161 .tbl = &arp_tbl, 162 .reachable_time = 30 * HZ, 163 .data = { 164 [NEIGH_VAR_MCAST_PROBES] = 3, 165 [NEIGH_VAR_UCAST_PROBES] = 3, 166 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ, 167 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ, 168 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ, 169 [NEIGH_VAR_GC_STALETIME] = 60 * HZ, 170 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX, 171 [NEIGH_VAR_PROXY_QLEN] = 64, 172 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ, 173 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10, 174 [NEIGH_VAR_LOCKTIME] = 1 * HZ, 175 }, 176 }, 177 .gc_interval = 30 * HZ, 178 .gc_thresh1 = 128, 179 .gc_thresh2 = 512, 180 .gc_thresh3 = 1024, 181 }; 182 EXPORT_SYMBOL(arp_tbl); 183 184 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 185 { 186 switch (dev->type) { 187 case ARPHRD_ETHER: 188 case ARPHRD_FDDI: 189 case ARPHRD_IEEE802: 190 ip_eth_mc_map(addr, haddr); 191 return 0; 192 case ARPHRD_INFINIBAND: 193 ip_ib_mc_map(addr, dev->broadcast, haddr); 194 return 0; 195 case ARPHRD_IPGRE: 196 ip_ipgre_mc_map(addr, dev->broadcast, haddr); 197 return 0; 198 default: 199 if (dir) { 200 memcpy(haddr, dev->broadcast, dev->addr_len); 201 return 0; 202 } 203 } 204 return -EINVAL; 205 } 206 207 208 static u32 arp_hash(const void *pkey, 209 const struct net_device *dev, 210 __u32 *hash_rnd) 211 { 212 return arp_hashfn(pkey, dev, hash_rnd); 213 } 214 215 static bool arp_key_eq(const struct neighbour *neigh, const void *pkey) 216 { 217 return neigh_key_eq32(neigh, pkey); 218 } 219 220 static int arp_constructor(struct neighbour *neigh) 221 { 222 __be32 addr; 223 struct net_device *dev = neigh->dev; 224 struct in_device *in_dev; 225 struct neigh_parms *parms; 226 u32 inaddr_any = INADDR_ANY; 227 228 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) 229 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len); 230 231 addr = *(__be32 *)neigh->primary_key; 232 rcu_read_lock(); 233 in_dev = __in_dev_get_rcu(dev); 234 if (!in_dev) { 235 rcu_read_unlock(); 236 return -EINVAL; 237 } 238 239 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr); 240 241 parms = in_dev->arp_parms; 242 __neigh_parms_put(neigh->parms); 243 neigh->parms = neigh_parms_clone(parms); 244 rcu_read_unlock(); 245 246 if (!dev->header_ops) { 247 neigh->nud_state = NUD_NOARP; 248 neigh->ops = &arp_direct_ops; 249 neigh->output = neigh_direct_output; 250 } else { 251 /* Good devices (checked by reading texts, but only Ethernet is 252 tested) 253 254 ARPHRD_ETHER: (ethernet, apfddi) 255 ARPHRD_FDDI: (fddi) 256 ARPHRD_IEEE802: (tr) 257 ARPHRD_METRICOM: (strip) 258 ARPHRD_ARCNET: 259 etc. etc. etc. 260 261 ARPHRD_IPDDP will also work, if author repairs it. 262 I did not it, because this driver does not work even 263 in old paradigm. 264 */ 265 266 if (neigh->type == RTN_MULTICAST) { 267 neigh->nud_state = NUD_NOARP; 268 arp_mc_map(addr, neigh->ha, dev, 1); 269 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 270 neigh->nud_state = NUD_NOARP; 271 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 272 } else if (neigh->type == RTN_BROADCAST || 273 (dev->flags & IFF_POINTOPOINT)) { 274 neigh->nud_state = NUD_NOARP; 275 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 276 } 277 278 if (dev->header_ops->cache) 279 neigh->ops = &arp_hh_ops; 280 else 281 neigh->ops = &arp_generic_ops; 282 283 if (neigh->nud_state & NUD_VALID) 284 neigh->output = neigh->ops->connected_output; 285 else 286 neigh->output = neigh->ops->output; 287 } 288 return 0; 289 } 290 291 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 292 { 293 dst_link_failure(skb); 294 kfree_skb(skb); 295 } 296 297 /* Create and send an arp packet. */ 298 static void arp_send_dst(int type, int ptype, __be32 dest_ip, 299 struct net_device *dev, __be32 src_ip, 300 const unsigned char *dest_hw, 301 const unsigned char *src_hw, 302 const unsigned char *target_hw, 303 struct dst_entry *dst) 304 { 305 struct sk_buff *skb; 306 307 /* arp on this interface. */ 308 if (dev->flags & IFF_NOARP) 309 return; 310 311 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 312 dest_hw, src_hw, target_hw); 313 if (!skb) 314 return; 315 316 skb_dst_set(skb, dst_clone(dst)); 317 arp_xmit(skb); 318 } 319 320 void arp_send(int type, int ptype, __be32 dest_ip, 321 struct net_device *dev, __be32 src_ip, 322 const unsigned char *dest_hw, const unsigned char *src_hw, 323 const unsigned char *target_hw) 324 { 325 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw, 326 target_hw, NULL); 327 } 328 EXPORT_SYMBOL(arp_send); 329 330 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 331 { 332 __be32 saddr = 0; 333 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL; 334 struct net_device *dev = neigh->dev; 335 __be32 target = *(__be32 *)neigh->primary_key; 336 int probes = atomic_read(&neigh->probes); 337 struct in_device *in_dev; 338 struct dst_entry *dst = NULL; 339 340 rcu_read_lock(); 341 in_dev = __in_dev_get_rcu(dev); 342 if (!in_dev) { 343 rcu_read_unlock(); 344 return; 345 } 346 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 347 default: 348 case 0: /* By default announce any local IP */ 349 if (skb && inet_addr_type_dev_table(dev_net(dev), dev, 350 ip_hdr(skb)->saddr) == RTN_LOCAL) 351 saddr = ip_hdr(skb)->saddr; 352 break; 353 case 1: /* Restrict announcements of saddr in same subnet */ 354 if (!skb) 355 break; 356 saddr = ip_hdr(skb)->saddr; 357 if (inet_addr_type_dev_table(dev_net(dev), dev, 358 saddr) == RTN_LOCAL) { 359 /* saddr should be known to target */ 360 if (inet_addr_onlink(in_dev, target, saddr)) 361 break; 362 } 363 saddr = 0; 364 break; 365 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 366 break; 367 } 368 rcu_read_unlock(); 369 370 if (!saddr) 371 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 372 373 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); 374 if (probes < 0) { 375 if (!(neigh->nud_state & NUD_VALID)) 376 pr_debug("trying to ucast probe in NUD_INVALID\n"); 377 neigh_ha_snapshot(dst_ha, neigh, dev); 378 dst_hw = dst_ha; 379 } else { 380 probes -= NEIGH_VAR(neigh->parms, APP_PROBES); 381 if (probes < 0) { 382 neigh_app_ns(neigh); 383 return; 384 } 385 } 386 387 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE)) 388 dst = skb_dst(skb); 389 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 390 dst_hw, dev->dev_addr, NULL, dst); 391 } 392 393 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 394 { 395 struct net *net = dev_net(in_dev->dev); 396 int scope; 397 398 switch (IN_DEV_ARP_IGNORE(in_dev)) { 399 case 0: /* Reply, the tip is already validated */ 400 return 0; 401 case 1: /* Reply only if tip is configured on the incoming interface */ 402 sip = 0; 403 scope = RT_SCOPE_HOST; 404 break; 405 case 2: /* 406 * Reply only if tip is configured on the incoming interface 407 * and is in same subnet as sip 408 */ 409 scope = RT_SCOPE_HOST; 410 break; 411 case 3: /* Do not reply for scope host addresses */ 412 sip = 0; 413 scope = RT_SCOPE_LINK; 414 in_dev = NULL; 415 break; 416 case 4: /* Reserved */ 417 case 5: 418 case 6: 419 case 7: 420 return 0; 421 case 8: /* Do not reply */ 422 return 1; 423 default: 424 return 0; 425 } 426 return !inet_confirm_addr(net, in_dev, sip, tip, scope); 427 } 428 429 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 430 { 431 struct rtable *rt; 432 int flag = 0; 433 /*unsigned long now; */ 434 struct net *net = dev_net(dev); 435 436 rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev)); 437 if (IS_ERR(rt)) 438 return 1; 439 if (rt->dst.dev != dev) { 440 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER); 441 flag = 1; 442 } 443 ip_rt_put(rt); 444 return flag; 445 } 446 447 /* 448 * Check if we can use proxy ARP for this path 449 */ 450 static inline int arp_fwd_proxy(struct in_device *in_dev, 451 struct net_device *dev, struct rtable *rt) 452 { 453 struct in_device *out_dev; 454 int imi, omi = -1; 455 456 if (rt->dst.dev == dev) 457 return 0; 458 459 if (!IN_DEV_PROXY_ARP(in_dev)) 460 return 0; 461 imi = IN_DEV_MEDIUM_ID(in_dev); 462 if (imi == 0) 463 return 1; 464 if (imi == -1) 465 return 0; 466 467 /* place to check for proxy_arp for routes */ 468 469 out_dev = __in_dev_get_rcu(rt->dst.dev); 470 if (out_dev) 471 omi = IN_DEV_MEDIUM_ID(out_dev); 472 473 return omi != imi && omi != -1; 474 } 475 476 /* 477 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 478 * 479 * RFC3069 supports proxy arp replies back to the same interface. This 480 * is done to support (ethernet) switch features, like RFC 3069, where 481 * the individual ports are not allowed to communicate with each 482 * other, BUT they are allowed to talk to the upstream router. As 483 * described in RFC 3069, it is possible to allow these hosts to 484 * communicate through the upstream router, by proxy_arp'ing. 485 * 486 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 487 * 488 * This technology is known by different names: 489 * In RFC 3069 it is called VLAN Aggregation. 490 * Cisco and Allied Telesyn call it Private VLAN. 491 * Hewlett-Packard call it Source-Port filtering or port-isolation. 492 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 493 * 494 */ 495 static inline int arp_fwd_pvlan(struct in_device *in_dev, 496 struct net_device *dev, struct rtable *rt, 497 __be32 sip, __be32 tip) 498 { 499 /* Private VLAN is only concerned about the same ethernet segment */ 500 if (rt->dst.dev != dev) 501 return 0; 502 503 /* Don't reply on self probes (often done by windowz boxes)*/ 504 if (sip == tip) 505 return 0; 506 507 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 508 return 1; 509 else 510 return 0; 511 } 512 513 /* 514 * Interface to link layer: send routine and receive handler. 515 */ 516 517 /* 518 * Create an arp packet. If dest_hw is not set, we create a broadcast 519 * message. 520 */ 521 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 522 struct net_device *dev, __be32 src_ip, 523 const unsigned char *dest_hw, 524 const unsigned char *src_hw, 525 const unsigned char *target_hw) 526 { 527 struct sk_buff *skb; 528 struct arphdr *arp; 529 unsigned char *arp_ptr; 530 int hlen = LL_RESERVED_SPACE(dev); 531 int tlen = dev->needed_tailroom; 532 533 /* 534 * Allocate a buffer 535 */ 536 537 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 538 if (!skb) 539 return NULL; 540 541 skb_reserve(skb, hlen); 542 skb_reset_network_header(skb); 543 arp = skb_put(skb, arp_hdr_len(dev)); 544 skb->dev = dev; 545 skb->protocol = htons(ETH_P_ARP); 546 if (!src_hw) 547 src_hw = dev->dev_addr; 548 if (!dest_hw) 549 dest_hw = dev->broadcast; 550 551 /* 552 * Fill the device header for the ARP frame 553 */ 554 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 555 goto out; 556 557 /* 558 * Fill out the arp protocol part. 559 * 560 * The arp hardware type should match the device type, except for FDDI, 561 * which (according to RFC 1390) should always equal 1 (Ethernet). 562 */ 563 /* 564 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 565 * DIX code for the protocol. Make these device structure fields. 566 */ 567 switch (dev->type) { 568 default: 569 arp->ar_hrd = htons(dev->type); 570 arp->ar_pro = htons(ETH_P_IP); 571 break; 572 573 #if IS_ENABLED(CONFIG_AX25) 574 case ARPHRD_AX25: 575 arp->ar_hrd = htons(ARPHRD_AX25); 576 arp->ar_pro = htons(AX25_P_IP); 577 break; 578 579 #if IS_ENABLED(CONFIG_NETROM) 580 case ARPHRD_NETROM: 581 arp->ar_hrd = htons(ARPHRD_NETROM); 582 arp->ar_pro = htons(AX25_P_IP); 583 break; 584 #endif 585 #endif 586 587 #if IS_ENABLED(CONFIG_FDDI) 588 case ARPHRD_FDDI: 589 arp->ar_hrd = htons(ARPHRD_ETHER); 590 arp->ar_pro = htons(ETH_P_IP); 591 break; 592 #endif 593 } 594 595 arp->ar_hln = dev->addr_len; 596 arp->ar_pln = 4; 597 arp->ar_op = htons(type); 598 599 arp_ptr = (unsigned char *)(arp + 1); 600 601 memcpy(arp_ptr, src_hw, dev->addr_len); 602 arp_ptr += dev->addr_len; 603 memcpy(arp_ptr, &src_ip, 4); 604 arp_ptr += 4; 605 606 switch (dev->type) { 607 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 608 case ARPHRD_IEEE1394: 609 break; 610 #endif 611 default: 612 if (target_hw) 613 memcpy(arp_ptr, target_hw, dev->addr_len); 614 else 615 memset(arp_ptr, 0, dev->addr_len); 616 arp_ptr += dev->addr_len; 617 } 618 memcpy(arp_ptr, &dest_ip, 4); 619 620 return skb; 621 622 out: 623 kfree_skb(skb); 624 return NULL; 625 } 626 EXPORT_SYMBOL(arp_create); 627 628 static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 629 { 630 return dev_queue_xmit(skb); 631 } 632 633 /* 634 * Send an arp packet. 635 */ 636 void arp_xmit(struct sk_buff *skb) 637 { 638 /* Send it off, maybe filter it using firewalling first. */ 639 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, 640 dev_net(skb->dev), NULL, skb, NULL, skb->dev, 641 arp_xmit_finish); 642 } 643 EXPORT_SYMBOL(arp_xmit); 644 645 static bool arp_is_garp(struct net *net, struct net_device *dev, 646 int *addr_type, __be16 ar_op, 647 __be32 sip, __be32 tip, 648 unsigned char *sha, unsigned char *tha) 649 { 650 bool is_garp = tip == sip; 651 652 /* Gratuitous ARP _replies_ also require target hwaddr to be 653 * the same as source. 654 */ 655 if (is_garp && ar_op == htons(ARPOP_REPLY)) 656 is_garp = 657 /* IPv4 over IEEE 1394 doesn't provide target 658 * hardware address field in its ARP payload. 659 */ 660 tha && 661 !memcmp(tha, sha, dev->addr_len); 662 663 if (is_garp) { 664 *addr_type = inet_addr_type_dev_table(net, dev, sip); 665 if (*addr_type != RTN_UNICAST) 666 is_garp = false; 667 } 668 return is_garp; 669 } 670 671 /* 672 * Process an arp request. 673 */ 674 675 static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb) 676 { 677 struct net_device *dev = skb->dev; 678 struct in_device *in_dev = __in_dev_get_rcu(dev); 679 struct arphdr *arp; 680 unsigned char *arp_ptr; 681 struct rtable *rt; 682 unsigned char *sha; 683 unsigned char *tha = NULL; 684 __be32 sip, tip; 685 u16 dev_type = dev->type; 686 int addr_type; 687 struct neighbour *n; 688 struct dst_entry *reply_dst = NULL; 689 bool is_garp = false; 690 691 /* arp_rcv below verifies the ARP header and verifies the device 692 * is ARP'able. 693 */ 694 695 if (!in_dev) 696 goto out_free_skb; 697 698 arp = arp_hdr(skb); 699 700 switch (dev_type) { 701 default: 702 if (arp->ar_pro != htons(ETH_P_IP) || 703 htons(dev_type) != arp->ar_hrd) 704 goto out_free_skb; 705 break; 706 case ARPHRD_ETHER: 707 case ARPHRD_FDDI: 708 case ARPHRD_IEEE802: 709 /* 710 * ETHERNET, and Fibre Channel (which are IEEE 802 711 * devices, according to RFC 2625) devices will accept ARP 712 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 713 * This is the case also of FDDI, where the RFC 1390 says that 714 * FDDI devices should accept ARP hardware of (1) Ethernet, 715 * however, to be more robust, we'll accept both 1 (Ethernet) 716 * or 6 (IEEE 802.2) 717 */ 718 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 719 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 720 arp->ar_pro != htons(ETH_P_IP)) 721 goto out_free_skb; 722 break; 723 case ARPHRD_AX25: 724 if (arp->ar_pro != htons(AX25_P_IP) || 725 arp->ar_hrd != htons(ARPHRD_AX25)) 726 goto out_free_skb; 727 break; 728 case ARPHRD_NETROM: 729 if (arp->ar_pro != htons(AX25_P_IP) || 730 arp->ar_hrd != htons(ARPHRD_NETROM)) 731 goto out_free_skb; 732 break; 733 } 734 735 /* Understand only these message types */ 736 737 if (arp->ar_op != htons(ARPOP_REPLY) && 738 arp->ar_op != htons(ARPOP_REQUEST)) 739 goto out_free_skb; 740 741 /* 742 * Extract fields 743 */ 744 arp_ptr = (unsigned char *)(arp + 1); 745 sha = arp_ptr; 746 arp_ptr += dev->addr_len; 747 memcpy(&sip, arp_ptr, 4); 748 arp_ptr += 4; 749 switch (dev_type) { 750 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 751 case ARPHRD_IEEE1394: 752 break; 753 #endif 754 default: 755 tha = arp_ptr; 756 arp_ptr += dev->addr_len; 757 } 758 memcpy(&tip, arp_ptr, 4); 759 /* 760 * Check for bad requests for 127.x.x.x and requests for multicast 761 * addresses. If this is one such, delete it. 762 */ 763 if (ipv4_is_multicast(tip) || 764 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) 765 goto out_free_skb; 766 767 /* 768 * For some 802.11 wireless deployments (and possibly other networks), 769 * there will be an ARP proxy and gratuitous ARP frames are attacks 770 * and thus should not be accepted. 771 */ 772 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP)) 773 goto out_free_skb; 774 775 /* 776 * Special case: We must set Frame Relay source Q.922 address 777 */ 778 if (dev_type == ARPHRD_DLCI) 779 sha = dev->broadcast; 780 781 /* 782 * Process entry. The idea here is we want to send a reply if it is a 783 * request for us or if it is a request for someone else that we hold 784 * a proxy for. We want to add an entry to our cache if it is a reply 785 * to us or if it is a request for our address. 786 * (The assumption for this last is that if someone is requesting our 787 * address, they are probably intending to talk to us, so it saves time 788 * if we cache their address. Their address is also probably not in 789 * our cache, since ours is not in their cache.) 790 * 791 * Putting this another way, we only care about replies if they are to 792 * us, in which case we add them to the cache. For requests, we care 793 * about those for us and those for our proxies. We reply to both, 794 * and in the case of requests for us we add the requester to the arp 795 * cache. 796 */ 797 798 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb)) 799 reply_dst = (struct dst_entry *) 800 iptunnel_metadata_reply(skb_metadata_dst(skb), 801 GFP_ATOMIC); 802 803 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 804 if (sip == 0) { 805 if (arp->ar_op == htons(ARPOP_REQUEST) && 806 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL && 807 !arp_ignore(in_dev, sip, tip)) 808 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, 809 sha, dev->dev_addr, sha, reply_dst); 810 goto out_consume_skb; 811 } 812 813 if (arp->ar_op == htons(ARPOP_REQUEST) && 814 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 815 816 rt = skb_rtable(skb); 817 addr_type = rt->rt_type; 818 819 if (addr_type == RTN_LOCAL) { 820 int dont_send; 821 822 dont_send = arp_ignore(in_dev, sip, tip); 823 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 824 dont_send = arp_filter(sip, tip, dev); 825 if (!dont_send) { 826 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 827 if (n) { 828 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 829 sip, dev, tip, sha, 830 dev->dev_addr, sha, 831 reply_dst); 832 neigh_release(n); 833 } 834 } 835 goto out_consume_skb; 836 } else if (IN_DEV_FORWARD(in_dev)) { 837 if (addr_type == RTN_UNICAST && 838 (arp_fwd_proxy(in_dev, dev, rt) || 839 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 840 (rt->dst.dev != dev && 841 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 842 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 843 if (n) 844 neigh_release(n); 845 846 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 847 skb->pkt_type == PACKET_HOST || 848 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { 849 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 850 sip, dev, tip, sha, 851 dev->dev_addr, sha, 852 reply_dst); 853 } else { 854 pneigh_enqueue(&arp_tbl, 855 in_dev->arp_parms, skb); 856 goto out_free_dst; 857 } 858 goto out_consume_skb; 859 } 860 } 861 } 862 863 /* Update our ARP tables */ 864 865 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 866 867 addr_type = -1; 868 if (n || IN_DEV_ARP_ACCEPT(in_dev)) { 869 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op, 870 sip, tip, sha, tha); 871 } 872 873 if (IN_DEV_ARP_ACCEPT(in_dev)) { 874 /* Unsolicited ARP is not accepted by default. 875 It is possible, that this option should be enabled for some 876 devices (strip is candidate) 877 */ 878 if (!n && 879 (is_garp || 880 (arp->ar_op == htons(ARPOP_REPLY) && 881 (addr_type == RTN_UNICAST || 882 (addr_type < 0 && 883 /* postpone calculation to as late as possible */ 884 inet_addr_type_dev_table(net, dev, sip) == 885 RTN_UNICAST))))) 886 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 887 } 888 889 if (n) { 890 int state = NUD_REACHABLE; 891 int override; 892 893 /* If several different ARP replies follows back-to-back, 894 use the FIRST one. It is possible, if several proxy 895 agents are active. Taking the first reply prevents 896 arp trashing and chooses the fastest router. 897 */ 898 override = time_after(jiffies, 899 n->updated + 900 NEIGH_VAR(n->parms, LOCKTIME)) || 901 is_garp; 902 903 /* Broadcast replies and request packets 904 do not assert neighbour reachability. 905 */ 906 if (arp->ar_op != htons(ARPOP_REPLY) || 907 skb->pkt_type != PACKET_HOST) 908 state = NUD_STALE; 909 neigh_update(n, sha, state, 910 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0); 911 neigh_release(n); 912 } 913 914 out_consume_skb: 915 consume_skb(skb); 916 917 out_free_dst: 918 dst_release(reply_dst); 919 return NET_RX_SUCCESS; 920 921 out_free_skb: 922 kfree_skb(skb); 923 return NET_RX_DROP; 924 } 925 926 static void parp_redo(struct sk_buff *skb) 927 { 928 arp_process(dev_net(skb->dev), NULL, skb); 929 } 930 931 932 /* 933 * Receive an arp request from the device layer. 934 */ 935 936 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 937 struct packet_type *pt, struct net_device *orig_dev) 938 { 939 const struct arphdr *arp; 940 941 /* do not tweak dropwatch on an ARP we will ignore */ 942 if (dev->flags & IFF_NOARP || 943 skb->pkt_type == PACKET_OTHERHOST || 944 skb->pkt_type == PACKET_LOOPBACK) 945 goto consumeskb; 946 947 skb = skb_share_check(skb, GFP_ATOMIC); 948 if (!skb) 949 goto out_of_mem; 950 951 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 952 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 953 goto freeskb; 954 955 arp = arp_hdr(skb); 956 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 957 goto freeskb; 958 959 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 960 961 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, 962 dev_net(dev), NULL, skb, dev, NULL, 963 arp_process); 964 965 consumeskb: 966 consume_skb(skb); 967 return NET_RX_SUCCESS; 968 freeskb: 969 kfree_skb(skb); 970 out_of_mem: 971 return NET_RX_DROP; 972 } 973 974 /* 975 * User level interface (ioctl) 976 */ 977 978 /* 979 * Set (create) an ARP cache entry. 980 */ 981 982 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 983 { 984 if (!dev) { 985 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 986 return 0; 987 } 988 if (__in_dev_get_rtnl(dev)) { 989 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 990 return 0; 991 } 992 return -ENXIO; 993 } 994 995 static int arp_req_set_public(struct net *net, struct arpreq *r, 996 struct net_device *dev) 997 { 998 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 999 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1000 1001 if (mask && mask != htonl(0xFFFFFFFF)) 1002 return -EINVAL; 1003 if (!dev && (r->arp_flags & ATF_COM)) { 1004 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 1005 r->arp_ha.sa_data); 1006 if (!dev) 1007 return -ENODEV; 1008 } 1009 if (mask) { 1010 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1)) 1011 return -ENOBUFS; 1012 return 0; 1013 } 1014 1015 return arp_req_set_proxy(net, dev, 1); 1016 } 1017 1018 static int arp_req_set(struct net *net, struct arpreq *r, 1019 struct net_device *dev) 1020 { 1021 __be32 ip; 1022 struct neighbour *neigh; 1023 int err; 1024 1025 if (r->arp_flags & ATF_PUBL) 1026 return arp_req_set_public(net, r, dev); 1027 1028 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1029 if (r->arp_flags & ATF_PERM) 1030 r->arp_flags |= ATF_COM; 1031 if (!dev) { 1032 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1033 1034 if (IS_ERR(rt)) 1035 return PTR_ERR(rt); 1036 dev = rt->dst.dev; 1037 ip_rt_put(rt); 1038 if (!dev) 1039 return -EINVAL; 1040 } 1041 switch (dev->type) { 1042 #if IS_ENABLED(CONFIG_FDDI) 1043 case ARPHRD_FDDI: 1044 /* 1045 * According to RFC 1390, FDDI devices should accept ARP 1046 * hardware types of 1 (Ethernet). However, to be more 1047 * robust, we'll accept hardware types of either 1 (Ethernet) 1048 * or 6 (IEEE 802.2). 1049 */ 1050 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1051 r->arp_ha.sa_family != ARPHRD_ETHER && 1052 r->arp_ha.sa_family != ARPHRD_IEEE802) 1053 return -EINVAL; 1054 break; 1055 #endif 1056 default: 1057 if (r->arp_ha.sa_family != dev->type) 1058 return -EINVAL; 1059 break; 1060 } 1061 1062 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1063 err = PTR_ERR(neigh); 1064 if (!IS_ERR(neigh)) { 1065 unsigned int state = NUD_STALE; 1066 if (r->arp_flags & ATF_PERM) 1067 state = NUD_PERMANENT; 1068 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1069 r->arp_ha.sa_data : NULL, state, 1070 NEIGH_UPDATE_F_OVERRIDE | 1071 NEIGH_UPDATE_F_ADMIN, 0); 1072 neigh_release(neigh); 1073 } 1074 return err; 1075 } 1076 1077 static unsigned int arp_state_to_flags(struct neighbour *neigh) 1078 { 1079 if (neigh->nud_state&NUD_PERMANENT) 1080 return ATF_PERM | ATF_COM; 1081 else if (neigh->nud_state&NUD_VALID) 1082 return ATF_COM; 1083 else 1084 return 0; 1085 } 1086 1087 /* 1088 * Get an ARP cache entry. 1089 */ 1090 1091 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1092 { 1093 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1094 struct neighbour *neigh; 1095 int err = -ENXIO; 1096 1097 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1098 if (neigh) { 1099 if (!(neigh->nud_state & NUD_NOARP)) { 1100 read_lock_bh(&neigh->lock); 1101 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1102 r->arp_flags = arp_state_to_flags(neigh); 1103 read_unlock_bh(&neigh->lock); 1104 r->arp_ha.sa_family = dev->type; 1105 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1106 err = 0; 1107 } 1108 neigh_release(neigh); 1109 } 1110 return err; 1111 } 1112 1113 static int arp_invalidate(struct net_device *dev, __be32 ip) 1114 { 1115 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1116 int err = -ENXIO; 1117 struct neigh_table *tbl = &arp_tbl; 1118 1119 if (neigh) { 1120 if (neigh->nud_state & ~NUD_NOARP) 1121 err = neigh_update(neigh, NULL, NUD_FAILED, 1122 NEIGH_UPDATE_F_OVERRIDE| 1123 NEIGH_UPDATE_F_ADMIN, 0); 1124 write_lock_bh(&tbl->lock); 1125 neigh_release(neigh); 1126 neigh_remove_one(neigh, tbl); 1127 write_unlock_bh(&tbl->lock); 1128 } 1129 1130 return err; 1131 } 1132 1133 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1134 struct net_device *dev) 1135 { 1136 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1137 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1138 1139 if (mask == htonl(0xFFFFFFFF)) 1140 return pneigh_delete(&arp_tbl, net, &ip, dev); 1141 1142 if (mask) 1143 return -EINVAL; 1144 1145 return arp_req_set_proxy(net, dev, 0); 1146 } 1147 1148 static int arp_req_delete(struct net *net, struct arpreq *r, 1149 struct net_device *dev) 1150 { 1151 __be32 ip; 1152 1153 if (r->arp_flags & ATF_PUBL) 1154 return arp_req_delete_public(net, r, dev); 1155 1156 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1157 if (!dev) { 1158 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1159 if (IS_ERR(rt)) 1160 return PTR_ERR(rt); 1161 dev = rt->dst.dev; 1162 ip_rt_put(rt); 1163 if (!dev) 1164 return -EINVAL; 1165 } 1166 return arp_invalidate(dev, ip); 1167 } 1168 1169 /* 1170 * Handle an ARP layer I/O control request. 1171 */ 1172 1173 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1174 { 1175 int err; 1176 struct arpreq r; 1177 struct net_device *dev = NULL; 1178 1179 switch (cmd) { 1180 case SIOCDARP: 1181 case SIOCSARP: 1182 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1183 return -EPERM; 1184 /* fall through */ 1185 case SIOCGARP: 1186 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1187 if (err) 1188 return -EFAULT; 1189 break; 1190 default: 1191 return -EINVAL; 1192 } 1193 1194 if (r.arp_pa.sa_family != AF_INET) 1195 return -EPFNOSUPPORT; 1196 1197 if (!(r.arp_flags & ATF_PUBL) && 1198 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1199 return -EINVAL; 1200 if (!(r.arp_flags & ATF_NETMASK)) 1201 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1202 htonl(0xFFFFFFFFUL); 1203 rtnl_lock(); 1204 if (r.arp_dev[0]) { 1205 err = -ENODEV; 1206 dev = __dev_get_by_name(net, r.arp_dev); 1207 if (!dev) 1208 goto out; 1209 1210 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1211 if (!r.arp_ha.sa_family) 1212 r.arp_ha.sa_family = dev->type; 1213 err = -EINVAL; 1214 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1215 goto out; 1216 } else if (cmd == SIOCGARP) { 1217 err = -ENODEV; 1218 goto out; 1219 } 1220 1221 switch (cmd) { 1222 case SIOCDARP: 1223 err = arp_req_delete(net, &r, dev); 1224 break; 1225 case SIOCSARP: 1226 err = arp_req_set(net, &r, dev); 1227 break; 1228 case SIOCGARP: 1229 err = arp_req_get(&r, dev); 1230 break; 1231 } 1232 out: 1233 rtnl_unlock(); 1234 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1235 err = -EFAULT; 1236 return err; 1237 } 1238 1239 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1240 void *ptr) 1241 { 1242 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1243 struct netdev_notifier_change_info *change_info; 1244 1245 switch (event) { 1246 case NETDEV_CHANGEADDR: 1247 neigh_changeaddr(&arp_tbl, dev); 1248 rt_cache_flush(dev_net(dev)); 1249 break; 1250 case NETDEV_CHANGE: 1251 change_info = ptr; 1252 if (change_info->flags_changed & IFF_NOARP) 1253 neigh_changeaddr(&arp_tbl, dev); 1254 if (!netif_carrier_ok(dev)) 1255 neigh_carrier_down(&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(NEIGH_ARP_TABLE, &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 void 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 buf[0] = '*'; 1332 buf[1] = '\0'; 1333 } 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%-17s * %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 /* ------------------------------------------------------------------------ */ 1420 1421 static int __net_init arp_net_init(struct net *net) 1422 { 1423 if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops, 1424 sizeof(struct neigh_seq_state))) 1425 return -ENOMEM; 1426 return 0; 1427 } 1428 1429 static void __net_exit arp_net_exit(struct net *net) 1430 { 1431 remove_proc_entry("arp", net->proc_net); 1432 } 1433 1434 static struct pernet_operations arp_net_ops = { 1435 .init = arp_net_init, 1436 .exit = arp_net_exit, 1437 }; 1438 1439 static int __init arp_proc_init(void) 1440 { 1441 return register_pernet_subsys(&arp_net_ops); 1442 } 1443 1444 #else /* CONFIG_PROC_FS */ 1445 1446 static int __init arp_proc_init(void) 1447 { 1448 return 0; 1449 } 1450 1451 #endif /* CONFIG_PROC_FS */ 1452