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 33 /* 34 * NUD stands for "neighbor unreachability detection" 35 */ 36 37 #define NUD_IN_TIMER (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE) 38 #define NUD_VALID (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY) 39 #define NUD_CONNECTED (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE) 40 41 struct neighbour; 42 43 enum { 44 NEIGH_VAR_MCAST_PROBES, 45 NEIGH_VAR_UCAST_PROBES, 46 NEIGH_VAR_APP_PROBES, 47 NEIGH_VAR_MCAST_REPROBES, 48 NEIGH_VAR_RETRANS_TIME, 49 NEIGH_VAR_BASE_REACHABLE_TIME, 50 NEIGH_VAR_DELAY_PROBE_TIME, 51 NEIGH_VAR_GC_STALETIME, 52 NEIGH_VAR_QUEUE_LEN_BYTES, 53 NEIGH_VAR_PROXY_QLEN, 54 NEIGH_VAR_ANYCAST_DELAY, 55 NEIGH_VAR_PROXY_DELAY, 56 NEIGH_VAR_LOCKTIME, 57 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1) 58 /* Following are used as a second way to access one of the above */ 59 NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */ 60 NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */ 61 NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */ 62 /* Following are used by "default" only */ 63 NEIGH_VAR_GC_INTERVAL, 64 NEIGH_VAR_GC_THRESH1, 65 NEIGH_VAR_GC_THRESH2, 66 NEIGH_VAR_GC_THRESH3, 67 NEIGH_VAR_MAX 68 }; 69 70 struct neigh_parms { 71 possible_net_t net; 72 struct net_device *dev; 73 struct list_head list; 74 int (*neigh_setup)(struct neighbour *); 75 void (*neigh_cleanup)(struct neighbour *); 76 struct neigh_table *tbl; 77 78 void *sysctl_table; 79 80 int dead; 81 refcount_t refcnt; 82 struct rcu_head rcu_head; 83 84 int reachable_time; 85 int data[NEIGH_VAR_DATA_MAX]; 86 DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX); 87 }; 88 89 static inline void neigh_var_set(struct neigh_parms *p, int index, int val) 90 { 91 set_bit(index, p->data_state); 92 p->data[index] = val; 93 } 94 95 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr]) 96 97 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used. 98 * In other cases, NEIGH_VAR_SET should be used. 99 */ 100 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val) 101 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val) 102 103 static inline void neigh_parms_data_state_setall(struct neigh_parms *p) 104 { 105 bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX); 106 } 107 108 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p) 109 { 110 bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX); 111 } 112 113 struct neigh_statistics { 114 unsigned long allocs; /* number of allocated neighs */ 115 unsigned long destroys; /* number of destroyed neighs */ 116 unsigned long hash_grows; /* number of hash resizes */ 117 118 unsigned long res_failed; /* number of failed resolutions */ 119 120 unsigned long lookups; /* number of lookups */ 121 unsigned long hits; /* number of hits (among lookups) */ 122 123 unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */ 124 unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */ 125 126 unsigned long periodic_gc_runs; /* number of periodic GC runs */ 127 unsigned long forced_gc_runs; /* number of forced GC runs */ 128 129 unsigned long unres_discards; /* number of unresolved drops */ 130 unsigned long table_fulls; /* times even gc couldn't help */ 131 }; 132 133 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field) 134 135 struct neighbour { 136 struct neighbour __rcu *next; 137 struct neigh_table *tbl; 138 struct neigh_parms *parms; 139 unsigned long confirmed; 140 unsigned long updated; 141 rwlock_t lock; 142 refcount_t refcnt; 143 struct sk_buff_head arp_queue; 144 unsigned int arp_queue_len_bytes; 145 struct timer_list timer; 146 unsigned long used; 147 atomic_t probes; 148 __u8 flags; 149 __u8 nud_state; 150 __u8 type; 151 __u8 dead; 152 seqlock_t ha_lock; 153 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))]; 154 struct hh_cache hh; 155 int (*output)(struct neighbour *, struct sk_buff *); 156 const struct neigh_ops *ops; 157 struct list_head gc_list; 158 struct rcu_head rcu; 159 struct net_device *dev; 160 u8 primary_key[0]; 161 } __randomize_layout; 162 163 struct neigh_ops { 164 int family; 165 void (*solicit)(struct neighbour *, struct sk_buff *); 166 void (*error_report)(struct neighbour *, struct sk_buff *); 167 int (*output)(struct neighbour *, struct sk_buff *); 168 int (*connected_output)(struct neighbour *, struct sk_buff *); 169 }; 170 171 struct pneigh_entry { 172 struct pneigh_entry *next; 173 possible_net_t net; 174 struct net_device *dev; 175 u8 flags; 176 u8 key[0]; 177 }; 178 179 /* 180 * neighbour table manipulation 181 */ 182 183 #define NEIGH_NUM_HASH_RND 4 184 185 struct neigh_hash_table { 186 struct neighbour __rcu **hash_buckets; 187 unsigned int hash_shift; 188 __u32 hash_rnd[NEIGH_NUM_HASH_RND]; 189 struct rcu_head rcu; 190 }; 191 192 193 struct neigh_table { 194 int family; 195 unsigned int entry_size; 196 unsigned int key_len; 197 __be16 protocol; 198 __u32 (*hash)(const void *pkey, 199 const struct net_device *dev, 200 __u32 *hash_rnd); 201 bool (*key_eq)(const struct neighbour *, const void *pkey); 202 int (*constructor)(struct neighbour *); 203 int (*pconstructor)(struct pneigh_entry *); 204 void (*pdestructor)(struct pneigh_entry *); 205 void (*proxy_redo)(struct sk_buff *skb); 206 char *id; 207 struct neigh_parms parms; 208 struct list_head parms_list; 209 int gc_interval; 210 int gc_thresh1; 211 int gc_thresh2; 212 int gc_thresh3; 213 unsigned long last_flush; 214 struct delayed_work gc_work; 215 struct timer_list proxy_timer; 216 struct sk_buff_head proxy_queue; 217 atomic_t entries; 218 atomic_t gc_entries; 219 struct list_head gc_list; 220 rwlock_t lock; 221 unsigned long last_rand; 222 struct neigh_statistics __percpu *stats; 223 struct neigh_hash_table __rcu *nht; 224 struct pneigh_entry **phash_buckets; 225 }; 226 227 enum { 228 NEIGH_ARP_TABLE = 0, 229 NEIGH_ND_TABLE = 1, 230 NEIGH_DN_TABLE = 2, 231 NEIGH_NR_TABLES, 232 NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */ 233 }; 234 235 static inline int neigh_parms_family(struct neigh_parms *p) 236 { 237 return p->tbl->family; 238 } 239 240 #define NEIGH_PRIV_ALIGN sizeof(long long) 241 #define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN) 242 243 static inline void *neighbour_priv(const struct neighbour *n) 244 { 245 return (char *)n + n->tbl->entry_size; 246 } 247 248 /* flags for neigh_update() */ 249 #define NEIGH_UPDATE_F_OVERRIDE 0x00000001 250 #define NEIGH_UPDATE_F_WEAK_OVERRIDE 0x00000002 251 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER 0x00000004 252 #define NEIGH_UPDATE_F_EXT_LEARNED 0x20000000 253 #define NEIGH_UPDATE_F_ISROUTER 0x40000000 254 #define NEIGH_UPDATE_F_ADMIN 0x80000000 255 256 257 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey) 258 { 259 return *(const u16 *)n->primary_key == *(const u16 *)pkey; 260 } 261 262 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey) 263 { 264 return *(const u32 *)n->primary_key == *(const u32 *)pkey; 265 } 266 267 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey) 268 { 269 const u32 *n32 = (const u32 *)n->primary_key; 270 const u32 *p32 = pkey; 271 272 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) | 273 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0; 274 } 275 276 static inline struct neighbour *___neigh_lookup_noref( 277 struct neigh_table *tbl, 278 bool (*key_eq)(const struct neighbour *n, const void *pkey), 279 __u32 (*hash)(const void *pkey, 280 const struct net_device *dev, 281 __u32 *hash_rnd), 282 const void *pkey, 283 struct net_device *dev) 284 { 285 struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht); 286 struct neighbour *n; 287 u32 hash_val; 288 289 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift); 290 for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]); 291 n != NULL; 292 n = rcu_dereference_bh(n->next)) { 293 if (n->dev == dev && key_eq(n, pkey)) 294 return n; 295 } 296 297 return NULL; 298 } 299 300 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl, 301 const void *pkey, 302 struct net_device *dev) 303 { 304 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev); 305 } 306 307 void neigh_table_init(int index, struct neigh_table *tbl); 308 int neigh_table_clear(int index, struct neigh_table *tbl); 309 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, 310 struct net_device *dev); 311 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net, 312 const void *pkey); 313 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey, 314 struct net_device *dev, bool want_ref); 315 static inline struct neighbour *neigh_create(struct neigh_table *tbl, 316 const void *pkey, 317 struct net_device *dev) 318 { 319 return __neigh_create(tbl, pkey, dev, true); 320 } 321 void neigh_destroy(struct neighbour *neigh); 322 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb); 323 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags, 324 u32 nlmsg_pid); 325 void __neigh_set_probe_once(struct neighbour *neigh); 326 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl); 327 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev); 328 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev); 329 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev); 330 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb); 331 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb); 332 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb); 333 struct neighbour *neigh_event_ns(struct neigh_table *tbl, 334 u8 *lladdr, void *saddr, 335 struct net_device *dev); 336 337 struct neigh_parms *neigh_parms_alloc(struct net_device *dev, 338 struct neigh_table *tbl); 339 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms); 340 341 static inline 342 struct net *neigh_parms_net(const struct neigh_parms *parms) 343 { 344 return read_pnet(&parms->net); 345 } 346 347 unsigned long neigh_rand_reach_time(unsigned long base); 348 349 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p, 350 struct sk_buff *skb); 351 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net, 352 const void *key, struct net_device *dev, 353 int creat); 354 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net, 355 const void *key, struct net_device *dev); 356 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, 357 struct net_device *dev); 358 359 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh) 360 { 361 return read_pnet(&pneigh->net); 362 } 363 364 void neigh_app_ns(struct neighbour *n); 365 void neigh_for_each(struct neigh_table *tbl, 366 void (*cb)(struct neighbour *, void *), void *cookie); 367 void __neigh_for_each_release(struct neigh_table *tbl, 368 int (*cb)(struct neighbour *)); 369 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *); 370 void pneigh_for_each(struct neigh_table *tbl, 371 void (*cb)(struct pneigh_entry *)); 372 373 struct neigh_seq_state { 374 struct seq_net_private p; 375 struct neigh_table *tbl; 376 struct neigh_hash_table *nht; 377 void *(*neigh_sub_iter)(struct neigh_seq_state *state, 378 struct neighbour *n, loff_t *pos); 379 unsigned int bucket; 380 unsigned int flags; 381 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001 382 #define NEIGH_SEQ_IS_PNEIGH 0x00000002 383 #define NEIGH_SEQ_SKIP_NOARP 0x00000004 384 }; 385 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, 386 unsigned int); 387 void *neigh_seq_next(struct seq_file *, void *, loff_t *); 388 void neigh_seq_stop(struct seq_file *, void *); 389 390 int neigh_proc_dointvec(struct ctl_table *ctl, int write, 391 void __user *buffer, size_t *lenp, loff_t *ppos); 392 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, 393 void __user *buffer, 394 size_t *lenp, loff_t *ppos); 395 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write, 396 void __user *buffer, 397 size_t *lenp, loff_t *ppos); 398 399 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p, 400 proc_handler *proc_handler); 401 void neigh_sysctl_unregister(struct neigh_parms *p); 402 403 static inline void __neigh_parms_put(struct neigh_parms *parms) 404 { 405 refcount_dec(&parms->refcnt); 406 } 407 408 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms) 409 { 410 refcount_inc(&parms->refcnt); 411 return parms; 412 } 413 414 /* 415 * Neighbour references 416 */ 417 418 static inline void neigh_release(struct neighbour *neigh) 419 { 420 if (refcount_dec_and_test(&neigh->refcnt)) 421 neigh_destroy(neigh); 422 } 423 424 static inline struct neighbour * neigh_clone(struct neighbour *neigh) 425 { 426 if (neigh) 427 refcount_inc(&neigh->refcnt); 428 return neigh; 429 } 430 431 #define neigh_hold(n) refcount_inc(&(n)->refcnt) 432 433 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb) 434 { 435 unsigned long now = jiffies; 436 437 if (neigh->used != now) 438 neigh->used = now; 439 if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE))) 440 return __neigh_event_send(neigh, skb); 441 return 0; 442 } 443 444 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 445 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb) 446 { 447 unsigned int seq, hh_alen; 448 449 do { 450 seq = read_seqbegin(&hh->hh_lock); 451 hh_alen = HH_DATA_ALIGN(ETH_HLEN); 452 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN); 453 } while (read_seqretry(&hh->hh_lock, seq)); 454 return 0; 455 } 456 #endif 457 458 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb) 459 { 460 unsigned int hh_alen = 0; 461 unsigned int seq; 462 unsigned int hh_len; 463 464 do { 465 seq = read_seqbegin(&hh->hh_lock); 466 hh_len = hh->hh_len; 467 if (likely(hh_len <= HH_DATA_MOD)) { 468 hh_alen = HH_DATA_MOD; 469 470 /* skb_push() would proceed silently if we have room for 471 * the unaligned size but not for the aligned size: 472 * check headroom explicitly. 473 */ 474 if (likely(skb_headroom(skb) >= HH_DATA_MOD)) { 475 /* this is inlined by gcc */ 476 memcpy(skb->data - HH_DATA_MOD, hh->hh_data, 477 HH_DATA_MOD); 478 } 479 } else { 480 hh_alen = HH_DATA_ALIGN(hh_len); 481 482 if (likely(skb_headroom(skb) >= hh_alen)) { 483 memcpy(skb->data - hh_alen, hh->hh_data, 484 hh_alen); 485 } 486 } 487 } while (read_seqretry(&hh->hh_lock, seq)); 488 489 if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) { 490 kfree_skb(skb); 491 return NET_XMIT_DROP; 492 } 493 494 __skb_push(skb, hh_len); 495 return dev_queue_xmit(skb); 496 } 497 498 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb) 499 { 500 const struct hh_cache *hh = &n->hh; 501 502 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len) 503 return neigh_hh_output(hh, skb); 504 else 505 return n->output(n, skb); 506 } 507 508 static inline struct neighbour * 509 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat) 510 { 511 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 512 513 if (n || !creat) 514 return n; 515 516 n = neigh_create(tbl, pkey, dev); 517 return IS_ERR(n) ? NULL : n; 518 } 519 520 static inline struct neighbour * 521 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey, 522 struct net_device *dev) 523 { 524 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 525 526 if (n) 527 return n; 528 529 return neigh_create(tbl, pkey, dev); 530 } 531 532 struct neighbour_cb { 533 unsigned long sched_next; 534 unsigned int flags; 535 }; 536 537 #define LOCALLY_ENQUEUED 0x1 538 539 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb) 540 541 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n, 542 const struct net_device *dev) 543 { 544 unsigned int seq; 545 546 do { 547 seq = read_seqbegin(&n->ha_lock); 548 memcpy(dst, n->ha, dev->addr_len); 549 } while (read_seqretry(&n->ha_lock, seq)); 550 } 551 552 static inline void neigh_update_ext_learned(struct neighbour *neigh, u32 flags, 553 int *notify) 554 { 555 u8 ndm_flags = 0; 556 557 if (!(flags & NEIGH_UPDATE_F_ADMIN)) 558 return; 559 560 ndm_flags |= (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0; 561 if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) { 562 if (ndm_flags & NTF_EXT_LEARNED) 563 neigh->flags |= NTF_EXT_LEARNED; 564 else 565 neigh->flags &= ~NTF_EXT_LEARNED; 566 *notify = 1; 567 } 568 } 569 570 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags, 571 int *notify) 572 { 573 u8 ndm_flags = 0; 574 575 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0; 576 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) { 577 if (ndm_flags & NTF_ROUTER) 578 neigh->flags |= NTF_ROUTER; 579 else 580 neigh->flags &= ~NTF_ROUTER; 581 *notify = 1; 582 } 583 } 584 #endif 585