1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _NET_NEIGHBOUR_H 3 #define _NET_NEIGHBOUR_H 4 5 #include <linux/neighbour.h> 6 7 /* 8 * Generic neighbour manipulation 9 * 10 * Authors: 11 * Pedro Roque <roque@di.fc.ul.pt> 12 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 13 * 14 * Changes: 15 * 16 * Harald Welte: <laforge@gnumonks.org> 17 * - Add neighbour cache statistics like rtstat 18 */ 19 20 #include <linux/atomic.h> 21 #include <linux/refcount.h> 22 #include <linux/netdevice.h> 23 #include <linux/skbuff.h> 24 #include <linux/rcupdate.h> 25 #include <linux/seq_file.h> 26 #include <linux/bitmap.h> 27 28 #include <linux/err.h> 29 #include <linux/sysctl.h> 30 #include <linux/workqueue.h> 31 #include <net/rtnetlink.h> 32 #include <net/neighbour_tables.h> 33 34 /* 35 * NUD stands for "neighbor unreachability detection" 36 */ 37 38 #define NUD_IN_TIMER (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE) 39 #define NUD_VALID (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY) 40 #define NUD_CONNECTED (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE) 41 42 struct neighbour; 43 44 enum { 45 NEIGH_VAR_MCAST_PROBES, 46 NEIGH_VAR_UCAST_PROBES, 47 NEIGH_VAR_APP_PROBES, 48 NEIGH_VAR_MCAST_REPROBES, 49 NEIGH_VAR_RETRANS_TIME, 50 NEIGH_VAR_BASE_REACHABLE_TIME, 51 NEIGH_VAR_DELAY_PROBE_TIME, 52 NEIGH_VAR_INTERVAL_PROBE_TIME_MS, 53 NEIGH_VAR_GC_STALETIME, 54 NEIGH_VAR_QUEUE_LEN_BYTES, 55 NEIGH_VAR_PROXY_QLEN, 56 NEIGH_VAR_ANYCAST_DELAY, 57 NEIGH_VAR_PROXY_DELAY, 58 NEIGH_VAR_LOCKTIME, 59 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1) 60 /* Following are used as a second way to access one of the above */ 61 NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */ 62 NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */ 63 NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */ 64 /* Following are used by "default" only */ 65 NEIGH_VAR_GC_INTERVAL, 66 NEIGH_VAR_GC_THRESH1, 67 NEIGH_VAR_GC_THRESH2, 68 NEIGH_VAR_GC_THRESH3, 69 NEIGH_VAR_MAX 70 }; 71 72 struct neigh_parms { 73 possible_net_t net; 74 struct net_device *dev; 75 netdevice_tracker dev_tracker; 76 struct list_head list; 77 int (*neigh_setup)(struct neighbour *); 78 struct neigh_table *tbl; 79 80 void *sysctl_table; 81 82 int dead; 83 refcount_t refcnt; 84 struct rcu_head rcu_head; 85 86 int reachable_time; 87 u32 qlen; 88 int data[NEIGH_VAR_DATA_MAX]; 89 DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX); 90 }; 91 92 static inline void neigh_var_set(struct neigh_parms *p, int index, int val) 93 { 94 set_bit(index, p->data_state); 95 p->data[index] = val; 96 } 97 98 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr]) 99 100 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used. 101 * In other cases, NEIGH_VAR_SET should be used. 102 */ 103 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val) 104 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val) 105 106 static inline void neigh_parms_data_state_setall(struct neigh_parms *p) 107 { 108 bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX); 109 } 110 111 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p) 112 { 113 bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX); 114 } 115 116 struct neigh_statistics { 117 unsigned long allocs; /* number of allocated neighs */ 118 unsigned long destroys; /* number of destroyed neighs */ 119 unsigned long hash_grows; /* number of hash resizes */ 120 121 unsigned long res_failed; /* number of failed resolutions */ 122 123 unsigned long lookups; /* number of lookups */ 124 unsigned long hits; /* number of hits (among lookups) */ 125 126 unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */ 127 unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */ 128 129 unsigned long periodic_gc_runs; /* number of periodic GC runs */ 130 unsigned long forced_gc_runs; /* number of forced GC runs */ 131 132 unsigned long unres_discards; /* number of unresolved drops */ 133 unsigned long table_fulls; /* times even gc couldn't help */ 134 }; 135 136 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field) 137 138 struct neighbour { 139 struct hlist_node hash; 140 struct hlist_node dev_list; 141 struct neigh_table *tbl; 142 struct neigh_parms *parms; 143 unsigned long confirmed; 144 unsigned long updated; 145 rwlock_t lock; 146 refcount_t refcnt; 147 unsigned int arp_queue_len_bytes; 148 struct sk_buff_head arp_queue; 149 struct timer_list timer; 150 unsigned long used; 151 atomic_t probes; 152 u8 nud_state; 153 u8 type; 154 u8 dead; 155 u8 protocol; 156 u32 flags; 157 seqlock_t ha_lock; 158 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8); 159 struct hh_cache hh; 160 int (*output)(struct neighbour *, struct sk_buff *); 161 const struct neigh_ops *ops; 162 struct list_head gc_list; 163 struct list_head managed_list; 164 struct rcu_head rcu; 165 struct net_device *dev; 166 netdevice_tracker dev_tracker; 167 u8 primary_key[]; 168 } __randomize_layout; 169 170 struct neigh_ops { 171 int family; 172 void (*solicit)(struct neighbour *, struct sk_buff *); 173 void (*error_report)(struct neighbour *, struct sk_buff *); 174 int (*output)(struct neighbour *, struct sk_buff *); 175 int (*connected_output)(struct neighbour *, struct sk_buff *); 176 }; 177 178 struct pneigh_entry { 179 struct pneigh_entry __rcu *next; 180 possible_net_t net; 181 struct net_device *dev; 182 netdevice_tracker dev_tracker; 183 union { 184 struct list_head free_node; 185 struct rcu_head rcu; 186 }; 187 u32 flags; 188 u8 protocol; 189 bool permanent; 190 u32 key[]; 191 }; 192 193 /* 194 * neighbour table manipulation 195 */ 196 197 #define NEIGH_NUM_HASH_RND 4 198 199 struct neigh_hash_table { 200 struct hlist_head *hash_heads; 201 unsigned int hash_shift; 202 __u32 hash_rnd[NEIGH_NUM_HASH_RND]; 203 struct rcu_head rcu; 204 }; 205 206 207 struct neigh_table { 208 int family; 209 unsigned int entry_size; 210 unsigned int key_len; 211 __be16 protocol; 212 __u32 (*hash)(const void *pkey, 213 const struct net_device *dev, 214 __u32 *hash_rnd); 215 bool (*key_eq)(const struct neighbour *, const void *pkey); 216 int (*constructor)(struct neighbour *); 217 int (*pconstructor)(struct pneigh_entry *); 218 void (*pdestructor)(struct pneigh_entry *); 219 void (*proxy_redo)(struct sk_buff *skb); 220 int (*is_multicast)(const void *pkey); 221 bool (*allow_add)(const struct net_device *dev, 222 struct netlink_ext_ack *extack); 223 char *id; 224 struct neigh_parms parms; 225 struct list_head parms_list; 226 int gc_interval; 227 int gc_thresh1; 228 int gc_thresh2; 229 int gc_thresh3; 230 unsigned long last_flush; 231 struct delayed_work gc_work; 232 struct delayed_work managed_work; 233 struct timer_list proxy_timer; 234 struct sk_buff_head proxy_queue; 235 atomic_t entries; 236 atomic_t gc_entries; 237 struct list_head gc_list; 238 struct list_head managed_list; 239 rwlock_t lock; 240 unsigned long last_rand; 241 struct neigh_statistics __percpu *stats; 242 struct neigh_hash_table __rcu *nht; 243 struct mutex phash_lock; 244 struct pneigh_entry __rcu **phash_buckets; 245 }; 246 247 static inline int neigh_parms_family(struct neigh_parms *p) 248 { 249 return p->tbl->family; 250 } 251 252 #define NEIGH_PRIV_ALIGN sizeof(long long) 253 #define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN) 254 255 static inline void *neighbour_priv(const struct neighbour *n) 256 { 257 return (char *)n + n->tbl->entry_size; 258 } 259 260 /* flags for neigh_update() */ 261 #define NEIGH_UPDATE_F_OVERRIDE BIT(0) 262 #define NEIGH_UPDATE_F_WEAK_OVERRIDE BIT(1) 263 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER BIT(2) 264 #define NEIGH_UPDATE_F_USE BIT(3) 265 #define NEIGH_UPDATE_F_MANAGED BIT(4) 266 #define NEIGH_UPDATE_F_EXT_LEARNED BIT(5) 267 #define NEIGH_UPDATE_F_ISROUTER BIT(6) 268 #define NEIGH_UPDATE_F_ADMIN BIT(7) 269 #define NEIGH_UPDATE_F_EXT_VALIDATED BIT(8) 270 271 /* In-kernel representation for NDA_FLAGS_EXT flags: */ 272 #define NTF_OLD_MASK 0xff 273 #define NTF_EXT_SHIFT 8 274 #define NTF_EXT_MASK (NTF_EXT_MANAGED | NTF_EXT_EXT_VALIDATED) 275 276 #define NTF_MANAGED (NTF_EXT_MANAGED << NTF_EXT_SHIFT) 277 #define NTF_EXT_VALIDATED (NTF_EXT_EXT_VALIDATED << NTF_EXT_SHIFT) 278 279 extern const struct nla_policy nda_policy[]; 280 281 #define neigh_for_each_in_bucket(pos, head) hlist_for_each_entry(pos, head, hash) 282 #define neigh_for_each_in_bucket_rcu(pos, head) \ 283 hlist_for_each_entry_rcu(pos, head, hash) 284 #define neigh_for_each_in_bucket_safe(pos, tmp, head) \ 285 hlist_for_each_entry_safe(pos, tmp, head, hash) 286 287 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey) 288 { 289 return *(const u32 *)n->primary_key == *(const u32 *)pkey; 290 } 291 292 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey) 293 { 294 const u32 *n32 = (const u32 *)n->primary_key; 295 const u32 *p32 = pkey; 296 297 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) | 298 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0; 299 } 300 301 static inline struct neighbour *___neigh_lookup_noref( 302 struct neigh_table *tbl, 303 bool (*key_eq)(const struct neighbour *n, const void *pkey), 304 __u32 (*hash)(const void *pkey, 305 const struct net_device *dev, 306 __u32 *hash_rnd), 307 const void *pkey, 308 struct net_device *dev) 309 { 310 struct neigh_hash_table *nht = rcu_dereference(tbl->nht); 311 struct neighbour *n; 312 u32 hash_val; 313 314 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift); 315 neigh_for_each_in_bucket_rcu(n, &nht->hash_heads[hash_val]) 316 if (n->dev == dev && key_eq(n, pkey)) 317 return n; 318 319 return NULL; 320 } 321 322 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl, 323 const void *pkey, 324 struct net_device *dev) 325 { 326 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev); 327 } 328 329 static inline void neigh_confirm(struct neighbour *n) 330 { 331 if (n) { 332 unsigned long now = jiffies; 333 334 /* avoid dirtying neighbour */ 335 if (READ_ONCE(n->confirmed) != now) 336 WRITE_ONCE(n->confirmed, now); 337 } 338 } 339 340 void neigh_table_init(int index, struct neigh_table *tbl); 341 int neigh_table_clear(int index, struct neigh_table *tbl); 342 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, 343 struct net_device *dev); 344 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey, 345 struct net_device *dev, bool want_ref); 346 static inline struct neighbour *neigh_create(struct neigh_table *tbl, 347 const void *pkey, 348 struct net_device *dev) 349 { 350 return __neigh_create(tbl, pkey, dev, true); 351 } 352 void neigh_destroy(struct neighbour *neigh); 353 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb, 354 const bool immediate_ok); 355 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags, 356 u32 nlmsg_pid); 357 void __neigh_set_probe_once(struct neighbour *neigh); 358 bool neigh_remove_one(struct neighbour *ndel); 359 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev); 360 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev); 361 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev); 362 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb); 363 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb); 364 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb); 365 struct neighbour *neigh_event_ns(struct neigh_table *tbl, 366 u8 *lladdr, void *saddr, 367 struct net_device *dev); 368 369 struct neigh_parms *neigh_parms_alloc(struct net_device *dev, 370 struct neigh_table *tbl); 371 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms); 372 373 static inline 374 struct net *neigh_parms_net(const struct neigh_parms *parms) 375 { 376 return read_pnet(&parms->net); 377 } 378 379 unsigned long neigh_rand_reach_time(unsigned long base); 380 381 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p, 382 struct sk_buff *skb); 383 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net, 384 const void *key, struct net_device *dev); 385 int pneigh_create(struct neigh_table *tbl, struct net *net, const void *key, 386 struct net_device *dev, u32 flags, u8 protocol, 387 bool permanent); 388 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, 389 struct net_device *dev); 390 391 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh) 392 { 393 return read_pnet(&pneigh->net); 394 } 395 396 void neigh_app_ns(struct neighbour *n); 397 void neigh_for_each(struct neigh_table *tbl, 398 void (*cb)(struct neighbour *, void *), void *cookie); 399 void __neigh_for_each_release(struct neigh_table *tbl, 400 int (*cb)(struct neighbour *)); 401 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *); 402 403 struct neigh_seq_state { 404 struct seq_net_private p; 405 struct neigh_table *tbl; 406 struct neigh_hash_table *nht; 407 void *(*neigh_sub_iter)(struct neigh_seq_state *state, 408 struct neighbour *n, loff_t *pos); 409 unsigned int bucket; 410 unsigned int flags; 411 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001 412 #define NEIGH_SEQ_IS_PNEIGH 0x00000002 413 #define NEIGH_SEQ_SKIP_NOARP 0x00000004 414 }; 415 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, 416 unsigned int); 417 void *neigh_seq_next(struct seq_file *, void *, loff_t *); 418 void neigh_seq_stop(struct seq_file *, void *); 419 420 int neigh_proc_dointvec(const struct ctl_table *ctl, int write, 421 void *buffer, size_t *lenp, loff_t *ppos); 422 int neigh_proc_dointvec_jiffies(const struct ctl_table *ctl, int write, 423 void *buffer, 424 size_t *lenp, loff_t *ppos); 425 int neigh_proc_dointvec_ms_jiffies(const struct ctl_table *ctl, int write, 426 void *buffer, size_t *lenp, loff_t *ppos); 427 428 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p, 429 proc_handler *proc_handler); 430 void neigh_sysctl_unregister(struct neigh_parms *p); 431 432 static inline void __neigh_parms_put(struct neigh_parms *parms) 433 { 434 refcount_dec(&parms->refcnt); 435 } 436 437 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms) 438 { 439 refcount_inc(&parms->refcnt); 440 return parms; 441 } 442 443 /* 444 * Neighbour references 445 */ 446 447 static inline void neigh_release(struct neighbour *neigh) 448 { 449 if (refcount_dec_and_test(&neigh->refcnt)) 450 neigh_destroy(neigh); 451 } 452 453 static inline struct neighbour * neigh_clone(struct neighbour *neigh) 454 { 455 if (neigh) 456 refcount_inc(&neigh->refcnt); 457 return neigh; 458 } 459 460 #define neigh_hold(n) refcount_inc(&(n)->refcnt) 461 462 static __always_inline int neigh_event_send_probe(struct neighbour *neigh, 463 struct sk_buff *skb, 464 const bool immediate_ok) 465 { 466 unsigned long now = jiffies; 467 468 if (READ_ONCE(neigh->used) != now) 469 WRITE_ONCE(neigh->used, now); 470 if (!(READ_ONCE(neigh->nud_state) & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE))) 471 return __neigh_event_send(neigh, skb, immediate_ok); 472 return 0; 473 } 474 475 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb) 476 { 477 return neigh_event_send_probe(neigh, skb, true); 478 } 479 480 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 481 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb) 482 { 483 unsigned int seq, hh_alen; 484 485 do { 486 seq = read_seqbegin(&hh->hh_lock); 487 hh_alen = HH_DATA_ALIGN(ETH_HLEN); 488 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN); 489 } while (read_seqretry(&hh->hh_lock, seq)); 490 return 0; 491 } 492 #endif 493 494 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb) 495 { 496 unsigned int hh_alen = 0; 497 unsigned int seq; 498 unsigned int hh_len; 499 500 do { 501 seq = read_seqbegin(&hh->hh_lock); 502 hh_len = READ_ONCE(hh->hh_len); 503 if (likely(hh_len <= HH_DATA_MOD)) { 504 hh_alen = HH_DATA_MOD; 505 506 /* skb_push() would proceed silently if we have room for 507 * the unaligned size but not for the aligned size: 508 * check headroom explicitly. 509 */ 510 if (likely(skb_headroom(skb) >= HH_DATA_MOD)) { 511 /* this is inlined by gcc */ 512 memcpy(skb->data - HH_DATA_MOD, hh->hh_data, 513 HH_DATA_MOD); 514 } 515 } else { 516 hh_alen = HH_DATA_ALIGN(hh_len); 517 518 if (likely(skb_headroom(skb) >= hh_alen)) { 519 memcpy(skb->data - hh_alen, hh->hh_data, 520 hh_alen); 521 } 522 } 523 } while (read_seqretry(&hh->hh_lock, seq)); 524 525 if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) { 526 kfree_skb(skb); 527 return NET_XMIT_DROP; 528 } 529 530 __skb_push(skb, hh_len); 531 return dev_queue_xmit(skb); 532 } 533 534 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb, 535 bool skip_cache) 536 { 537 const struct hh_cache *hh = &n->hh; 538 539 /* n->nud_state and hh->hh_len could be changed under us. 540 * neigh_hh_output() is taking care of the race later. 541 */ 542 if (!skip_cache && 543 (READ_ONCE(n->nud_state) & NUD_CONNECTED) && 544 READ_ONCE(hh->hh_len)) 545 return neigh_hh_output(hh, skb); 546 547 return READ_ONCE(n->output)(n, skb); 548 } 549 550 static inline struct neighbour * 551 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat) 552 { 553 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 554 555 if (n || !creat) 556 return n; 557 558 n = neigh_create(tbl, pkey, dev); 559 return IS_ERR(n) ? NULL : n; 560 } 561 562 static inline struct neighbour * 563 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey, 564 struct net_device *dev) 565 { 566 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 567 568 if (n) 569 return n; 570 571 return neigh_create(tbl, pkey, dev); 572 } 573 574 struct neighbour_cb { 575 unsigned long sched_next; 576 unsigned int flags; 577 }; 578 579 #define LOCALLY_ENQUEUED 0x1 580 581 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb) 582 583 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n, 584 const struct net_device *dev) 585 { 586 unsigned int seq; 587 588 do { 589 seq = read_seqbegin(&n->ha_lock); 590 memcpy(dst, n->ha, dev->addr_len); 591 } while (read_seqretry(&n->ha_lock, seq)); 592 } 593 594 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags, 595 int *notify) 596 { 597 u8 ndm_flags = 0; 598 599 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0; 600 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) { 601 if (ndm_flags & NTF_ROUTER) 602 neigh->flags |= NTF_ROUTER; 603 else 604 neigh->flags &= ~NTF_ROUTER; 605 *notify = 1; 606 } 607 } 608 #endif 609