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 static int arp_is_multicast(const void *pkey); 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 struct neigh_table arp_tbl = { 153 .family = AF_INET, 154 .key_len = 4, 155 .protocol = cpu_to_be16(ETH_P_IP), 156 .hash = arp_hash, 157 .key_eq = arp_key_eq, 158 .constructor = arp_constructor, 159 .proxy_redo = parp_redo, 160 .is_multicast = arp_is_multicast, 161 .id = "arp_cache", 162 .parms = { 163 .tbl = &arp_tbl, 164 .reachable_time = 30 * HZ, 165 .data = { 166 [NEIGH_VAR_MCAST_PROBES] = 3, 167 [NEIGH_VAR_UCAST_PROBES] = 3, 168 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ, 169 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ, 170 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ, 171 [NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ, 172 [NEIGH_VAR_GC_STALETIME] = 60 * HZ, 173 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX, 174 [NEIGH_VAR_PROXY_QLEN] = 64, 175 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ, 176 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10, 177 [NEIGH_VAR_LOCKTIME] = 1 * HZ, 178 }, 179 }, 180 .gc_interval = 30 * HZ, 181 .gc_thresh1 = 128, 182 .gc_thresh2 = 512, 183 .gc_thresh3 = 1024, 184 }; 185 EXPORT_SYMBOL(arp_tbl); 186 187 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) 188 { 189 switch (dev->type) { 190 case ARPHRD_ETHER: 191 case ARPHRD_FDDI: 192 case ARPHRD_IEEE802: 193 ip_eth_mc_map(addr, haddr); 194 return 0; 195 case ARPHRD_INFINIBAND: 196 ip_ib_mc_map(addr, dev->broadcast, haddr); 197 return 0; 198 case ARPHRD_IPGRE: 199 ip_ipgre_mc_map(addr, dev->broadcast, haddr); 200 return 0; 201 default: 202 if (dir) { 203 memcpy(haddr, dev->broadcast, dev->addr_len); 204 return 0; 205 } 206 } 207 return -EINVAL; 208 } 209 210 211 static u32 arp_hash(const void *pkey, 212 const struct net_device *dev, 213 __u32 *hash_rnd) 214 { 215 return arp_hashfn(pkey, dev, hash_rnd); 216 } 217 218 static bool arp_key_eq(const struct neighbour *neigh, const void *pkey) 219 { 220 return neigh_key_eq32(neigh, pkey); 221 } 222 223 static int arp_constructor(struct neighbour *neigh) 224 { 225 __be32 addr; 226 struct net_device *dev = neigh->dev; 227 struct in_device *in_dev; 228 struct neigh_parms *parms; 229 u32 inaddr_any = INADDR_ANY; 230 231 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) 232 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len); 233 234 addr = *(__be32 *)neigh->primary_key; 235 rcu_read_lock(); 236 in_dev = __in_dev_get_rcu(dev); 237 if (!in_dev) { 238 rcu_read_unlock(); 239 return -EINVAL; 240 } 241 242 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr); 243 244 parms = in_dev->arp_parms; 245 __neigh_parms_put(neigh->parms); 246 neigh->parms = neigh_parms_clone(parms); 247 rcu_read_unlock(); 248 249 if (!dev->header_ops) { 250 neigh->nud_state = NUD_NOARP; 251 neigh->ops = &arp_direct_ops; 252 neigh->output = neigh_direct_output; 253 } else { 254 /* Good devices (checked by reading texts, but only Ethernet is 255 tested) 256 257 ARPHRD_ETHER: (ethernet, apfddi) 258 ARPHRD_FDDI: (fddi) 259 ARPHRD_IEEE802: (tr) 260 ARPHRD_METRICOM: (strip) 261 ARPHRD_ARCNET: 262 etc. etc. etc. 263 264 ARPHRD_IPDDP will also work, if author repairs it. 265 I did not it, because this driver does not work even 266 in old paradigm. 267 */ 268 269 if (neigh->type == RTN_MULTICAST) { 270 neigh->nud_state = NUD_NOARP; 271 arp_mc_map(addr, neigh->ha, dev, 1); 272 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { 273 neigh->nud_state = NUD_NOARP; 274 memcpy(neigh->ha, dev->dev_addr, dev->addr_len); 275 } else if (neigh->type == RTN_BROADCAST || 276 (dev->flags & IFF_POINTOPOINT)) { 277 neigh->nud_state = NUD_NOARP; 278 memcpy(neigh->ha, dev->broadcast, dev->addr_len); 279 } 280 281 if (dev->header_ops->cache) 282 neigh->ops = &arp_hh_ops; 283 else 284 neigh->ops = &arp_generic_ops; 285 286 if (neigh->nud_state & NUD_VALID) 287 neigh->output = neigh->ops->connected_output; 288 else 289 neigh->output = neigh->ops->output; 290 } 291 return 0; 292 } 293 294 static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) 295 { 296 dst_link_failure(skb); 297 kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_FAILED); 298 } 299 300 /* Create and send an arp packet. */ 301 static void arp_send_dst(int type, int ptype, __be32 dest_ip, 302 struct net_device *dev, __be32 src_ip, 303 const unsigned char *dest_hw, 304 const unsigned char *src_hw, 305 const unsigned char *target_hw, 306 struct dst_entry *dst) 307 { 308 struct sk_buff *skb; 309 310 /* arp on this interface. */ 311 if (dev->flags & IFF_NOARP) 312 return; 313 314 skb = arp_create(type, ptype, dest_ip, dev, src_ip, 315 dest_hw, src_hw, target_hw); 316 if (!skb) 317 return; 318 319 skb_dst_set(skb, dst_clone(dst)); 320 arp_xmit(skb); 321 } 322 323 void arp_send(int type, int ptype, __be32 dest_ip, 324 struct net_device *dev, __be32 src_ip, 325 const unsigned char *dest_hw, const unsigned char *src_hw, 326 const unsigned char *target_hw) 327 { 328 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw, 329 target_hw, NULL); 330 } 331 EXPORT_SYMBOL(arp_send); 332 333 static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) 334 { 335 __be32 saddr = 0; 336 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL; 337 struct net_device *dev = neigh->dev; 338 __be32 target = *(__be32 *)neigh->primary_key; 339 int probes = atomic_read(&neigh->probes); 340 struct in_device *in_dev; 341 struct dst_entry *dst = NULL; 342 343 rcu_read_lock(); 344 in_dev = __in_dev_get_rcu(dev); 345 if (!in_dev) { 346 rcu_read_unlock(); 347 return; 348 } 349 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { 350 default: 351 case 0: /* By default announce any local IP */ 352 if (skb && inet_addr_type_dev_table(dev_net(dev), dev, 353 ip_hdr(skb)->saddr) == RTN_LOCAL) 354 saddr = ip_hdr(skb)->saddr; 355 break; 356 case 1: /* Restrict announcements of saddr in same subnet */ 357 if (!skb) 358 break; 359 saddr = ip_hdr(skb)->saddr; 360 if (inet_addr_type_dev_table(dev_net(dev), dev, 361 saddr) == RTN_LOCAL) { 362 /* saddr should be known to target */ 363 if (inet_addr_onlink(in_dev, target, saddr)) 364 break; 365 } 366 saddr = 0; 367 break; 368 case 2: /* Avoid secondary IPs, get a primary/preferred one */ 369 break; 370 } 371 rcu_read_unlock(); 372 373 if (!saddr) 374 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); 375 376 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); 377 if (probes < 0) { 378 if (!(neigh->nud_state & NUD_VALID)) 379 pr_debug("trying to ucast probe in NUD_INVALID\n"); 380 neigh_ha_snapshot(dst_ha, neigh, dev); 381 dst_hw = dst_ha; 382 } else { 383 probes -= NEIGH_VAR(neigh->parms, APP_PROBES); 384 if (probes < 0) { 385 neigh_app_ns(neigh); 386 return; 387 } 388 } 389 390 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE)) 391 dst = skb_dst(skb); 392 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, 393 dst_hw, dev->dev_addr, NULL, dst); 394 } 395 396 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) 397 { 398 struct net *net = dev_net(in_dev->dev); 399 int scope; 400 401 switch (IN_DEV_ARP_IGNORE(in_dev)) { 402 case 0: /* Reply, the tip is already validated */ 403 return 0; 404 case 1: /* Reply only if tip is configured on the incoming interface */ 405 sip = 0; 406 scope = RT_SCOPE_HOST; 407 break; 408 case 2: /* 409 * Reply only if tip is configured on the incoming interface 410 * and is in same subnet as sip 411 */ 412 scope = RT_SCOPE_HOST; 413 break; 414 case 3: /* Do not reply for scope host addresses */ 415 sip = 0; 416 scope = RT_SCOPE_LINK; 417 in_dev = NULL; 418 break; 419 case 4: /* Reserved */ 420 case 5: 421 case 6: 422 case 7: 423 return 0; 424 case 8: /* Do not reply */ 425 return 1; 426 default: 427 return 0; 428 } 429 return !inet_confirm_addr(net, in_dev, sip, tip, scope); 430 } 431 432 static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) 433 { 434 struct rtable *rt; 435 int flag = 0; 436 /*unsigned long now; */ 437 struct net *net = dev_net(dev); 438 439 rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev)); 440 if (IS_ERR(rt)) 441 return 1; 442 if (rt->dst.dev != dev) { 443 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER); 444 flag = 1; 445 } 446 ip_rt_put(rt); 447 return flag; 448 } 449 450 /* 451 * Check if we can use proxy ARP for this path 452 */ 453 static inline int arp_fwd_proxy(struct in_device *in_dev, 454 struct net_device *dev, struct rtable *rt) 455 { 456 struct in_device *out_dev; 457 int imi, omi = -1; 458 459 if (rt->dst.dev == dev) 460 return 0; 461 462 if (!IN_DEV_PROXY_ARP(in_dev)) 463 return 0; 464 imi = IN_DEV_MEDIUM_ID(in_dev); 465 if (imi == 0) 466 return 1; 467 if (imi == -1) 468 return 0; 469 470 /* place to check for proxy_arp for routes */ 471 472 out_dev = __in_dev_get_rcu(rt->dst.dev); 473 if (out_dev) 474 omi = IN_DEV_MEDIUM_ID(out_dev); 475 476 return omi != imi && omi != -1; 477 } 478 479 /* 480 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) 481 * 482 * RFC3069 supports proxy arp replies back to the same interface. This 483 * is done to support (ethernet) switch features, like RFC 3069, where 484 * the individual ports are not allowed to communicate with each 485 * other, BUT they are allowed to talk to the upstream router. As 486 * described in RFC 3069, it is possible to allow these hosts to 487 * communicate through the upstream router, by proxy_arp'ing. 488 * 489 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" 490 * 491 * This technology is known by different names: 492 * In RFC 3069 it is called VLAN Aggregation. 493 * Cisco and Allied Telesyn call it Private VLAN. 494 * Hewlett-Packard call it Source-Port filtering or port-isolation. 495 * Ericsson call it MAC-Forced Forwarding (RFC Draft). 496 * 497 */ 498 static inline int arp_fwd_pvlan(struct in_device *in_dev, 499 struct net_device *dev, struct rtable *rt, 500 __be32 sip, __be32 tip) 501 { 502 /* Private VLAN is only concerned about the same ethernet segment */ 503 if (rt->dst.dev != dev) 504 return 0; 505 506 /* Don't reply on self probes (often done by windowz boxes)*/ 507 if (sip == tip) 508 return 0; 509 510 if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) 511 return 1; 512 else 513 return 0; 514 } 515 516 /* 517 * Interface to link layer: send routine and receive handler. 518 */ 519 520 /* 521 * Create an arp packet. If dest_hw is not set, we create a broadcast 522 * message. 523 */ 524 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 525 struct net_device *dev, __be32 src_ip, 526 const unsigned char *dest_hw, 527 const unsigned char *src_hw, 528 const unsigned char *target_hw) 529 { 530 struct sk_buff *skb; 531 struct arphdr *arp; 532 unsigned char *arp_ptr; 533 int hlen = LL_RESERVED_SPACE(dev); 534 int tlen = dev->needed_tailroom; 535 536 /* 537 * Allocate a buffer 538 */ 539 540 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); 541 if (!skb) 542 return NULL; 543 544 skb_reserve(skb, hlen); 545 skb_reset_network_header(skb); 546 arp = skb_put(skb, arp_hdr_len(dev)); 547 skb->dev = dev; 548 skb->protocol = htons(ETH_P_ARP); 549 if (!src_hw) 550 src_hw = dev->dev_addr; 551 if (!dest_hw) 552 dest_hw = dev->broadcast; 553 554 /* 555 * Fill the device header for the ARP frame 556 */ 557 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) 558 goto out; 559 560 /* 561 * Fill out the arp protocol part. 562 * 563 * The arp hardware type should match the device type, except for FDDI, 564 * which (according to RFC 1390) should always equal 1 (Ethernet). 565 */ 566 /* 567 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the 568 * DIX code for the protocol. Make these device structure fields. 569 */ 570 switch (dev->type) { 571 default: 572 arp->ar_hrd = htons(dev->type); 573 arp->ar_pro = htons(ETH_P_IP); 574 break; 575 576 #if IS_ENABLED(CONFIG_AX25) 577 case ARPHRD_AX25: 578 arp->ar_hrd = htons(ARPHRD_AX25); 579 arp->ar_pro = htons(AX25_P_IP); 580 break; 581 582 #if IS_ENABLED(CONFIG_NETROM) 583 case ARPHRD_NETROM: 584 arp->ar_hrd = htons(ARPHRD_NETROM); 585 arp->ar_pro = htons(AX25_P_IP); 586 break; 587 #endif 588 #endif 589 590 #if IS_ENABLED(CONFIG_FDDI) 591 case ARPHRD_FDDI: 592 arp->ar_hrd = htons(ARPHRD_ETHER); 593 arp->ar_pro = htons(ETH_P_IP); 594 break; 595 #endif 596 } 597 598 arp->ar_hln = dev->addr_len; 599 arp->ar_pln = 4; 600 arp->ar_op = htons(type); 601 602 arp_ptr = (unsigned char *)(arp + 1); 603 604 memcpy(arp_ptr, src_hw, dev->addr_len); 605 arp_ptr += dev->addr_len; 606 memcpy(arp_ptr, &src_ip, 4); 607 arp_ptr += 4; 608 609 switch (dev->type) { 610 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 611 case ARPHRD_IEEE1394: 612 break; 613 #endif 614 default: 615 if (target_hw) 616 memcpy(arp_ptr, target_hw, dev->addr_len); 617 else 618 memset(arp_ptr, 0, dev->addr_len); 619 arp_ptr += dev->addr_len; 620 } 621 memcpy(arp_ptr, &dest_ip, 4); 622 623 return skb; 624 625 out: 626 kfree_skb(skb); 627 return NULL; 628 } 629 EXPORT_SYMBOL(arp_create); 630 631 static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 632 { 633 return dev_queue_xmit(skb); 634 } 635 636 /* 637 * Send an arp packet. 638 */ 639 void arp_xmit(struct sk_buff *skb) 640 { 641 /* Send it off, maybe filter it using firewalling first. */ 642 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, 643 dev_net(skb->dev), NULL, skb, NULL, skb->dev, 644 arp_xmit_finish); 645 } 646 EXPORT_SYMBOL(arp_xmit); 647 648 static bool arp_is_garp(struct net *net, struct net_device *dev, 649 int *addr_type, __be16 ar_op, 650 __be32 sip, __be32 tip, 651 unsigned char *sha, unsigned char *tha) 652 { 653 bool is_garp = tip == sip; 654 655 /* Gratuitous ARP _replies_ also require target hwaddr to be 656 * the same as source. 657 */ 658 if (is_garp && ar_op == htons(ARPOP_REPLY)) 659 is_garp = 660 /* IPv4 over IEEE 1394 doesn't provide target 661 * hardware address field in its ARP payload. 662 */ 663 tha && 664 !memcmp(tha, sha, dev->addr_len); 665 666 if (is_garp) { 667 *addr_type = inet_addr_type_dev_table(net, dev, sip); 668 if (*addr_type != RTN_UNICAST) 669 is_garp = false; 670 } 671 return is_garp; 672 } 673 674 /* 675 * Process an arp request. 676 */ 677 678 static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb) 679 { 680 struct net_device *dev = skb->dev; 681 struct in_device *in_dev = __in_dev_get_rcu(dev); 682 struct arphdr *arp; 683 unsigned char *arp_ptr; 684 struct rtable *rt; 685 unsigned char *sha; 686 unsigned char *tha = NULL; 687 __be32 sip, tip; 688 u16 dev_type = dev->type; 689 int addr_type; 690 struct neighbour *n; 691 struct dst_entry *reply_dst = NULL; 692 bool is_garp = false; 693 694 /* arp_rcv below verifies the ARP header and verifies the device 695 * is ARP'able. 696 */ 697 698 if (!in_dev) 699 goto out_free_skb; 700 701 arp = arp_hdr(skb); 702 703 switch (dev_type) { 704 default: 705 if (arp->ar_pro != htons(ETH_P_IP) || 706 htons(dev_type) != arp->ar_hrd) 707 goto out_free_skb; 708 break; 709 case ARPHRD_ETHER: 710 case ARPHRD_FDDI: 711 case ARPHRD_IEEE802: 712 /* 713 * ETHERNET, and Fibre Channel (which are IEEE 802 714 * devices, according to RFC 2625) devices will accept ARP 715 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). 716 * This is the case also of FDDI, where the RFC 1390 says that 717 * FDDI devices should accept ARP hardware of (1) Ethernet, 718 * however, to be more robust, we'll accept both 1 (Ethernet) 719 * or 6 (IEEE 802.2) 720 */ 721 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 722 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 723 arp->ar_pro != htons(ETH_P_IP)) 724 goto out_free_skb; 725 break; 726 case ARPHRD_AX25: 727 if (arp->ar_pro != htons(AX25_P_IP) || 728 arp->ar_hrd != htons(ARPHRD_AX25)) 729 goto out_free_skb; 730 break; 731 case ARPHRD_NETROM: 732 if (arp->ar_pro != htons(AX25_P_IP) || 733 arp->ar_hrd != htons(ARPHRD_NETROM)) 734 goto out_free_skb; 735 break; 736 } 737 738 /* Understand only these message types */ 739 740 if (arp->ar_op != htons(ARPOP_REPLY) && 741 arp->ar_op != htons(ARPOP_REQUEST)) 742 goto out_free_skb; 743 744 /* 745 * Extract fields 746 */ 747 arp_ptr = (unsigned char *)(arp + 1); 748 sha = arp_ptr; 749 arp_ptr += dev->addr_len; 750 memcpy(&sip, arp_ptr, 4); 751 arp_ptr += 4; 752 switch (dev_type) { 753 #if IS_ENABLED(CONFIG_FIREWIRE_NET) 754 case ARPHRD_IEEE1394: 755 break; 756 #endif 757 default: 758 tha = arp_ptr; 759 arp_ptr += dev->addr_len; 760 } 761 memcpy(&tip, arp_ptr, 4); 762 /* 763 * Check for bad requests for 127.x.x.x and requests for multicast 764 * addresses. If this is one such, delete it. 765 */ 766 if (ipv4_is_multicast(tip) || 767 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) 768 goto out_free_skb; 769 770 /* 771 * For some 802.11 wireless deployments (and possibly other networks), 772 * there will be an ARP proxy and gratuitous ARP frames are attacks 773 * and thus should not be accepted. 774 */ 775 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP)) 776 goto out_free_skb; 777 778 /* 779 * Special case: We must set Frame Relay source Q.922 address 780 */ 781 if (dev_type == ARPHRD_DLCI) 782 sha = dev->broadcast; 783 784 /* 785 * Process entry. The idea here is we want to send a reply if it is a 786 * request for us or if it is a request for someone else that we hold 787 * a proxy for. We want to add an entry to our cache if it is a reply 788 * to us or if it is a request for our address. 789 * (The assumption for this last is that if someone is requesting our 790 * address, they are probably intending to talk to us, so it saves time 791 * if we cache their address. Their address is also probably not in 792 * our cache, since ours is not in their cache.) 793 * 794 * Putting this another way, we only care about replies if they are to 795 * us, in which case we add them to the cache. For requests, we care 796 * about those for us and those for our proxies. We reply to both, 797 * and in the case of requests for us we add the requester to the arp 798 * cache. 799 */ 800 801 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb)) 802 reply_dst = (struct dst_entry *) 803 iptunnel_metadata_reply(skb_metadata_dst(skb), 804 GFP_ATOMIC); 805 806 /* Special case: IPv4 duplicate address detection packet (RFC2131) */ 807 if (sip == 0) { 808 if (arp->ar_op == htons(ARPOP_REQUEST) && 809 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL && 810 !arp_ignore(in_dev, sip, tip)) 811 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, 812 sha, dev->dev_addr, sha, reply_dst); 813 goto out_consume_skb; 814 } 815 816 if (arp->ar_op == htons(ARPOP_REQUEST) && 817 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { 818 819 rt = skb_rtable(skb); 820 addr_type = rt->rt_type; 821 822 if (addr_type == RTN_LOCAL) { 823 int dont_send; 824 825 dont_send = arp_ignore(in_dev, sip, tip); 826 if (!dont_send && IN_DEV_ARPFILTER(in_dev)) 827 dont_send = arp_filter(sip, tip, dev); 828 if (!dont_send) { 829 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 830 if (n) { 831 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 832 sip, dev, tip, sha, 833 dev->dev_addr, sha, 834 reply_dst); 835 neigh_release(n); 836 } 837 } 838 goto out_consume_skb; 839 } else if (IN_DEV_FORWARD(in_dev)) { 840 if (addr_type == RTN_UNICAST && 841 (arp_fwd_proxy(in_dev, dev, rt) || 842 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || 843 (rt->dst.dev != dev && 844 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { 845 n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 846 if (n) 847 neigh_release(n); 848 849 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || 850 skb->pkt_type == PACKET_HOST || 851 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { 852 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, 853 sip, dev, tip, sha, 854 dev->dev_addr, sha, 855 reply_dst); 856 } else { 857 pneigh_enqueue(&arp_tbl, 858 in_dev->arp_parms, skb); 859 goto out_free_dst; 860 } 861 goto out_consume_skb; 862 } 863 } 864 } 865 866 /* Update our ARP tables */ 867 868 n = __neigh_lookup(&arp_tbl, &sip, dev, 0); 869 870 addr_type = -1; 871 if (n || IN_DEV_ARP_ACCEPT(in_dev)) { 872 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op, 873 sip, tip, sha, tha); 874 } 875 876 if (IN_DEV_ARP_ACCEPT(in_dev)) { 877 /* Unsolicited ARP is not accepted by default. 878 It is possible, that this option should be enabled for some 879 devices (strip is candidate) 880 */ 881 if (!n && 882 (is_garp || 883 (arp->ar_op == htons(ARPOP_REPLY) && 884 (addr_type == RTN_UNICAST || 885 (addr_type < 0 && 886 /* postpone calculation to as late as possible */ 887 inet_addr_type_dev_table(net, dev, sip) == 888 RTN_UNICAST))))) 889 n = __neigh_lookup(&arp_tbl, &sip, dev, 1); 890 } 891 892 if (n) { 893 int state = NUD_REACHABLE; 894 int override; 895 896 /* If several different ARP replies follows back-to-back, 897 use the FIRST one. It is possible, if several proxy 898 agents are active. Taking the first reply prevents 899 arp trashing and chooses the fastest router. 900 */ 901 override = time_after(jiffies, 902 n->updated + 903 NEIGH_VAR(n->parms, LOCKTIME)) || 904 is_garp; 905 906 /* Broadcast replies and request packets 907 do not assert neighbour reachability. 908 */ 909 if (arp->ar_op != htons(ARPOP_REPLY) || 910 skb->pkt_type != PACKET_HOST) 911 state = NUD_STALE; 912 neigh_update(n, sha, state, 913 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0); 914 neigh_release(n); 915 } 916 917 out_consume_skb: 918 consume_skb(skb); 919 920 out_free_dst: 921 dst_release(reply_dst); 922 return NET_RX_SUCCESS; 923 924 out_free_skb: 925 kfree_skb(skb); 926 return NET_RX_DROP; 927 } 928 929 static void parp_redo(struct sk_buff *skb) 930 { 931 arp_process(dev_net(skb->dev), NULL, skb); 932 } 933 934 static int arp_is_multicast(const void *pkey) 935 { 936 return ipv4_is_multicast(*((__be32 *)pkey)); 937 } 938 939 /* 940 * Receive an arp request from the device layer. 941 */ 942 943 static int arp_rcv(struct sk_buff *skb, struct net_device *dev, 944 struct packet_type *pt, struct net_device *orig_dev) 945 { 946 const struct arphdr *arp; 947 948 /* do not tweak dropwatch on an ARP we will ignore */ 949 if (dev->flags & IFF_NOARP || 950 skb->pkt_type == PACKET_OTHERHOST || 951 skb->pkt_type == PACKET_LOOPBACK) 952 goto consumeskb; 953 954 skb = skb_share_check(skb, GFP_ATOMIC); 955 if (!skb) 956 goto out_of_mem; 957 958 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ 959 if (!pskb_may_pull(skb, arp_hdr_len(dev))) 960 goto freeskb; 961 962 arp = arp_hdr(skb); 963 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) 964 goto freeskb; 965 966 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); 967 968 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, 969 dev_net(dev), NULL, skb, dev, NULL, 970 arp_process); 971 972 consumeskb: 973 consume_skb(skb); 974 return NET_RX_SUCCESS; 975 freeskb: 976 kfree_skb(skb); 977 out_of_mem: 978 return NET_RX_DROP; 979 } 980 981 /* 982 * User level interface (ioctl) 983 */ 984 985 /* 986 * Set (create) an ARP cache entry. 987 */ 988 989 static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) 990 { 991 if (!dev) { 992 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; 993 return 0; 994 } 995 if (__in_dev_get_rtnl(dev)) { 996 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); 997 return 0; 998 } 999 return -ENXIO; 1000 } 1001 1002 static int arp_req_set_public(struct net *net, struct arpreq *r, 1003 struct net_device *dev) 1004 { 1005 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1006 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1007 1008 if (mask && mask != htonl(0xFFFFFFFF)) 1009 return -EINVAL; 1010 if (!dev && (r->arp_flags & ATF_COM)) { 1011 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, 1012 r->arp_ha.sa_data); 1013 if (!dev) 1014 return -ENODEV; 1015 } 1016 if (mask) { 1017 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1)) 1018 return -ENOBUFS; 1019 return 0; 1020 } 1021 1022 return arp_req_set_proxy(net, dev, 1); 1023 } 1024 1025 static int arp_req_set(struct net *net, struct arpreq *r, 1026 struct net_device *dev) 1027 { 1028 __be32 ip; 1029 struct neighbour *neigh; 1030 int err; 1031 1032 if (r->arp_flags & ATF_PUBL) 1033 return arp_req_set_public(net, r, dev); 1034 1035 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1036 if (r->arp_flags & ATF_PERM) 1037 r->arp_flags |= ATF_COM; 1038 if (!dev) { 1039 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1040 1041 if (IS_ERR(rt)) 1042 return PTR_ERR(rt); 1043 dev = rt->dst.dev; 1044 ip_rt_put(rt); 1045 if (!dev) 1046 return -EINVAL; 1047 } 1048 switch (dev->type) { 1049 #if IS_ENABLED(CONFIG_FDDI) 1050 case ARPHRD_FDDI: 1051 /* 1052 * According to RFC 1390, FDDI devices should accept ARP 1053 * hardware types of 1 (Ethernet). However, to be more 1054 * robust, we'll accept hardware types of either 1 (Ethernet) 1055 * or 6 (IEEE 802.2). 1056 */ 1057 if (r->arp_ha.sa_family != ARPHRD_FDDI && 1058 r->arp_ha.sa_family != ARPHRD_ETHER && 1059 r->arp_ha.sa_family != ARPHRD_IEEE802) 1060 return -EINVAL; 1061 break; 1062 #endif 1063 default: 1064 if (r->arp_ha.sa_family != dev->type) 1065 return -EINVAL; 1066 break; 1067 } 1068 1069 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); 1070 err = PTR_ERR(neigh); 1071 if (!IS_ERR(neigh)) { 1072 unsigned int state = NUD_STALE; 1073 if (r->arp_flags & ATF_PERM) 1074 state = NUD_PERMANENT; 1075 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? 1076 r->arp_ha.sa_data : NULL, state, 1077 NEIGH_UPDATE_F_OVERRIDE | 1078 NEIGH_UPDATE_F_ADMIN, 0); 1079 neigh_release(neigh); 1080 } 1081 return err; 1082 } 1083 1084 static unsigned int arp_state_to_flags(struct neighbour *neigh) 1085 { 1086 if (neigh->nud_state&NUD_PERMANENT) 1087 return ATF_PERM | ATF_COM; 1088 else if (neigh->nud_state&NUD_VALID) 1089 return ATF_COM; 1090 else 1091 return 0; 1092 } 1093 1094 /* 1095 * Get an ARP cache entry. 1096 */ 1097 1098 static int arp_req_get(struct arpreq *r, struct net_device *dev) 1099 { 1100 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1101 struct neighbour *neigh; 1102 int err = -ENXIO; 1103 1104 neigh = neigh_lookup(&arp_tbl, &ip, dev); 1105 if (neigh) { 1106 if (!(neigh->nud_state & NUD_NOARP)) { 1107 read_lock_bh(&neigh->lock); 1108 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); 1109 r->arp_flags = arp_state_to_flags(neigh); 1110 read_unlock_bh(&neigh->lock); 1111 r->arp_ha.sa_family = dev->type; 1112 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); 1113 err = 0; 1114 } 1115 neigh_release(neigh); 1116 } 1117 return err; 1118 } 1119 1120 int arp_invalidate(struct net_device *dev, __be32 ip, bool force) 1121 { 1122 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); 1123 int err = -ENXIO; 1124 struct neigh_table *tbl = &arp_tbl; 1125 1126 if (neigh) { 1127 if ((neigh->nud_state & NUD_VALID) && !force) { 1128 neigh_release(neigh); 1129 return 0; 1130 } 1131 1132 if (neigh->nud_state & ~NUD_NOARP) 1133 err = neigh_update(neigh, NULL, NUD_FAILED, 1134 NEIGH_UPDATE_F_OVERRIDE| 1135 NEIGH_UPDATE_F_ADMIN, 0); 1136 write_lock_bh(&tbl->lock); 1137 neigh_release(neigh); 1138 neigh_remove_one(neigh, tbl); 1139 write_unlock_bh(&tbl->lock); 1140 } 1141 1142 return err; 1143 } 1144 1145 static int arp_req_delete_public(struct net *net, struct arpreq *r, 1146 struct net_device *dev) 1147 { 1148 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; 1149 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; 1150 1151 if (mask == htonl(0xFFFFFFFF)) 1152 return pneigh_delete(&arp_tbl, net, &ip, dev); 1153 1154 if (mask) 1155 return -EINVAL; 1156 1157 return arp_req_set_proxy(net, dev, 0); 1158 } 1159 1160 static int arp_req_delete(struct net *net, struct arpreq *r, 1161 struct net_device *dev) 1162 { 1163 __be32 ip; 1164 1165 if (r->arp_flags & ATF_PUBL) 1166 return arp_req_delete_public(net, r, dev); 1167 1168 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; 1169 if (!dev) { 1170 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); 1171 if (IS_ERR(rt)) 1172 return PTR_ERR(rt); 1173 dev = rt->dst.dev; 1174 ip_rt_put(rt); 1175 if (!dev) 1176 return -EINVAL; 1177 } 1178 return arp_invalidate(dev, ip, true); 1179 } 1180 1181 /* 1182 * Handle an ARP layer I/O control request. 1183 */ 1184 1185 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) 1186 { 1187 int err; 1188 struct arpreq r; 1189 struct net_device *dev = NULL; 1190 1191 switch (cmd) { 1192 case SIOCDARP: 1193 case SIOCSARP: 1194 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1195 return -EPERM; 1196 fallthrough; 1197 case SIOCGARP: 1198 err = copy_from_user(&r, arg, sizeof(struct arpreq)); 1199 if (err) 1200 return -EFAULT; 1201 break; 1202 default: 1203 return -EINVAL; 1204 } 1205 1206 if (r.arp_pa.sa_family != AF_INET) 1207 return -EPFNOSUPPORT; 1208 1209 if (!(r.arp_flags & ATF_PUBL) && 1210 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) 1211 return -EINVAL; 1212 if (!(r.arp_flags & ATF_NETMASK)) 1213 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = 1214 htonl(0xFFFFFFFFUL); 1215 rtnl_lock(); 1216 if (r.arp_dev[0]) { 1217 err = -ENODEV; 1218 dev = __dev_get_by_name(net, r.arp_dev); 1219 if (!dev) 1220 goto out; 1221 1222 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ 1223 if (!r.arp_ha.sa_family) 1224 r.arp_ha.sa_family = dev->type; 1225 err = -EINVAL; 1226 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) 1227 goto out; 1228 } else if (cmd == SIOCGARP) { 1229 err = -ENODEV; 1230 goto out; 1231 } 1232 1233 switch (cmd) { 1234 case SIOCDARP: 1235 err = arp_req_delete(net, &r, dev); 1236 break; 1237 case SIOCSARP: 1238 err = arp_req_set(net, &r, dev); 1239 break; 1240 case SIOCGARP: 1241 err = arp_req_get(&r, dev); 1242 break; 1243 } 1244 out: 1245 rtnl_unlock(); 1246 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) 1247 err = -EFAULT; 1248 return err; 1249 } 1250 1251 static int arp_netdev_event(struct notifier_block *this, unsigned long event, 1252 void *ptr) 1253 { 1254 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1255 struct netdev_notifier_change_info *change_info; 1256 struct in_device *in_dev; 1257 bool evict_nocarrier; 1258 1259 switch (event) { 1260 case NETDEV_CHANGEADDR: 1261 neigh_changeaddr(&arp_tbl, dev); 1262 rt_cache_flush(dev_net(dev)); 1263 break; 1264 case NETDEV_CHANGE: 1265 change_info = ptr; 1266 if (change_info->flags_changed & IFF_NOARP) 1267 neigh_changeaddr(&arp_tbl, dev); 1268 1269 in_dev = __in_dev_get_rtnl(dev); 1270 if (!in_dev) 1271 evict_nocarrier = true; 1272 else 1273 evict_nocarrier = IN_DEV_ARP_EVICT_NOCARRIER(in_dev); 1274 1275 if (evict_nocarrier && !netif_carrier_ok(dev)) 1276 neigh_carrier_down(&arp_tbl, dev); 1277 break; 1278 default: 1279 break; 1280 } 1281 1282 return NOTIFY_DONE; 1283 } 1284 1285 static struct notifier_block arp_netdev_notifier = { 1286 .notifier_call = arp_netdev_event, 1287 }; 1288 1289 /* Note, that it is not on notifier chain. 1290 It is necessary, that this routine was called after route cache will be 1291 flushed. 1292 */ 1293 void arp_ifdown(struct net_device *dev) 1294 { 1295 neigh_ifdown(&arp_tbl, dev); 1296 } 1297 1298 1299 /* 1300 * Called once on startup. 1301 */ 1302 1303 static struct packet_type arp_packet_type __read_mostly = { 1304 .type = cpu_to_be16(ETH_P_ARP), 1305 .func = arp_rcv, 1306 }; 1307 1308 #ifdef CONFIG_PROC_FS 1309 #if IS_ENABLED(CONFIG_AX25) 1310 1311 /* 1312 * ax25 -> ASCII conversion 1313 */ 1314 static void ax2asc2(ax25_address *a, char *buf) 1315 { 1316 char c, *s; 1317 int n; 1318 1319 for (n = 0, s = buf; n < 6; n++) { 1320 c = (a->ax25_call[n] >> 1) & 0x7F; 1321 1322 if (c != ' ') 1323 *s++ = c; 1324 } 1325 1326 *s++ = '-'; 1327 n = (a->ax25_call[6] >> 1) & 0x0F; 1328 if (n > 9) { 1329 *s++ = '1'; 1330 n -= 10; 1331 } 1332 1333 *s++ = n + '0'; 1334 *s++ = '\0'; 1335 1336 if (*buf == '\0' || *buf == '-') { 1337 buf[0] = '*'; 1338 buf[1] = '\0'; 1339 } 1340 } 1341 #endif /* CONFIG_AX25 */ 1342 1343 #define HBUFFERLEN 30 1344 1345 static void arp_format_neigh_entry(struct seq_file *seq, 1346 struct neighbour *n) 1347 { 1348 char hbuffer[HBUFFERLEN]; 1349 int k, j; 1350 char tbuf[16]; 1351 struct net_device *dev = n->dev; 1352 int hatype = dev->type; 1353 1354 read_lock(&n->lock); 1355 /* Convert hardware address to XX:XX:XX:XX ... form. */ 1356 #if IS_ENABLED(CONFIG_AX25) 1357 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) 1358 ax2asc2((ax25_address *)n->ha, hbuffer); 1359 else { 1360 #endif 1361 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { 1362 hbuffer[k++] = hex_asc_hi(n->ha[j]); 1363 hbuffer[k++] = hex_asc_lo(n->ha[j]); 1364 hbuffer[k++] = ':'; 1365 } 1366 if (k != 0) 1367 --k; 1368 hbuffer[k] = 0; 1369 #if IS_ENABLED(CONFIG_AX25) 1370 } 1371 #endif 1372 sprintf(tbuf, "%pI4", n->primary_key); 1373 seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n", 1374 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); 1375 read_unlock(&n->lock); 1376 } 1377 1378 static void arp_format_pneigh_entry(struct seq_file *seq, 1379 struct pneigh_entry *n) 1380 { 1381 struct net_device *dev = n->dev; 1382 int hatype = dev ? dev->type : 0; 1383 char tbuf[16]; 1384 1385 sprintf(tbuf, "%pI4", n->key); 1386 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", 1387 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", 1388 dev ? dev->name : "*"); 1389 } 1390 1391 static int arp_seq_show(struct seq_file *seq, void *v) 1392 { 1393 if (v == SEQ_START_TOKEN) { 1394 seq_puts(seq, "IP address HW type Flags " 1395 "HW address Mask Device\n"); 1396 } else { 1397 struct neigh_seq_state *state = seq->private; 1398 1399 if (state->flags & NEIGH_SEQ_IS_PNEIGH) 1400 arp_format_pneigh_entry(seq, v); 1401 else 1402 arp_format_neigh_entry(seq, v); 1403 } 1404 1405 return 0; 1406 } 1407 1408 static void *arp_seq_start(struct seq_file *seq, loff_t *pos) 1409 { 1410 /* Don't want to confuse "arp -a" w/ magic entries, 1411 * so we tell the generic iterator to skip NUD_NOARP. 1412 */ 1413 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); 1414 } 1415 1416 static const struct seq_operations arp_seq_ops = { 1417 .start = arp_seq_start, 1418 .next = neigh_seq_next, 1419 .stop = neigh_seq_stop, 1420 .show = arp_seq_show, 1421 }; 1422 #endif /* CONFIG_PROC_FS */ 1423 1424 static int __net_init arp_net_init(struct net *net) 1425 { 1426 if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops, 1427 sizeof(struct neigh_seq_state))) 1428 return -ENOMEM; 1429 return 0; 1430 } 1431 1432 static void __net_exit arp_net_exit(struct net *net) 1433 { 1434 remove_proc_entry("arp", net->proc_net); 1435 } 1436 1437 static struct pernet_operations arp_net_ops = { 1438 .init = arp_net_init, 1439 .exit = arp_net_exit, 1440 }; 1441 1442 void __init arp_init(void) 1443 { 1444 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl); 1445 1446 dev_add_pack(&arp_packet_type); 1447 register_pernet_subsys(&arp_net_ops); 1448 #ifdef CONFIG_SYSCTL 1449 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL); 1450 #endif 1451 register_netdevice_notifier(&arp_netdev_notifier); 1452 } 1453