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 rcu_head rcu; 158 struct net_device *dev; 159 u8 primary_key[0]; 160 } __randomize_layout; 161 162 struct neigh_ops { 163 int family; 164 void (*solicit)(struct neighbour *, struct sk_buff *); 165 void (*error_report)(struct neighbour *, struct sk_buff *); 166 int (*output)(struct neighbour *, struct sk_buff *); 167 int (*connected_output)(struct neighbour *, struct sk_buff *); 168 }; 169 170 struct pneigh_entry { 171 struct pneigh_entry *next; 172 possible_net_t net; 173 struct net_device *dev; 174 u8 flags; 175 u8 key[0]; 176 }; 177 178 /* 179 * neighbour table manipulation 180 */ 181 182 #define NEIGH_NUM_HASH_RND 4 183 184 struct neigh_hash_table { 185 struct neighbour __rcu **hash_buckets; 186 unsigned int hash_shift; 187 __u32 hash_rnd[NEIGH_NUM_HASH_RND]; 188 struct rcu_head rcu; 189 }; 190 191 192 struct neigh_table { 193 int family; 194 unsigned int entry_size; 195 unsigned int key_len; 196 __be16 protocol; 197 __u32 (*hash)(const void *pkey, 198 const struct net_device *dev, 199 __u32 *hash_rnd); 200 bool (*key_eq)(const struct neighbour *, const void *pkey); 201 int (*constructor)(struct neighbour *); 202 int (*pconstructor)(struct pneigh_entry *); 203 void (*pdestructor)(struct pneigh_entry *); 204 void (*proxy_redo)(struct sk_buff *skb); 205 char *id; 206 struct neigh_parms parms; 207 struct list_head parms_list; 208 int gc_interval; 209 int gc_thresh1; 210 int gc_thresh2; 211 int gc_thresh3; 212 unsigned long last_flush; 213 struct delayed_work gc_work; 214 struct timer_list proxy_timer; 215 struct sk_buff_head proxy_queue; 216 atomic_t entries; 217 rwlock_t lock; 218 unsigned long last_rand; 219 struct neigh_statistics __percpu *stats; 220 struct neigh_hash_table __rcu *nht; 221 struct pneigh_entry **phash_buckets; 222 }; 223 224 enum { 225 NEIGH_ARP_TABLE = 0, 226 NEIGH_ND_TABLE = 1, 227 NEIGH_DN_TABLE = 2, 228 NEIGH_NR_TABLES, 229 NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */ 230 }; 231 232 static inline int neigh_parms_family(struct neigh_parms *p) 233 { 234 return p->tbl->family; 235 } 236 237 #define NEIGH_PRIV_ALIGN sizeof(long long) 238 #define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN) 239 240 static inline void *neighbour_priv(const struct neighbour *n) 241 { 242 return (char *)n + n->tbl->entry_size; 243 } 244 245 /* flags for neigh_update() */ 246 #define NEIGH_UPDATE_F_OVERRIDE 0x00000001 247 #define NEIGH_UPDATE_F_WEAK_OVERRIDE 0x00000002 248 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER 0x00000004 249 #define NEIGH_UPDATE_F_EXT_LEARNED 0x20000000 250 #define NEIGH_UPDATE_F_ISROUTER 0x40000000 251 #define NEIGH_UPDATE_F_ADMIN 0x80000000 252 253 254 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey) 255 { 256 return *(const u16 *)n->primary_key == *(const u16 *)pkey; 257 } 258 259 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey) 260 { 261 return *(const u32 *)n->primary_key == *(const u32 *)pkey; 262 } 263 264 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey) 265 { 266 const u32 *n32 = (const u32 *)n->primary_key; 267 const u32 *p32 = pkey; 268 269 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) | 270 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0; 271 } 272 273 static inline struct neighbour *___neigh_lookup_noref( 274 struct neigh_table *tbl, 275 bool (*key_eq)(const struct neighbour *n, const void *pkey), 276 __u32 (*hash)(const void *pkey, 277 const struct net_device *dev, 278 __u32 *hash_rnd), 279 const void *pkey, 280 struct net_device *dev) 281 { 282 struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht); 283 struct neighbour *n; 284 u32 hash_val; 285 286 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift); 287 for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]); 288 n != NULL; 289 n = rcu_dereference_bh(n->next)) { 290 if (n->dev == dev && key_eq(n, pkey)) 291 return n; 292 } 293 294 return NULL; 295 } 296 297 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl, 298 const void *pkey, 299 struct net_device *dev) 300 { 301 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev); 302 } 303 304 void neigh_table_init(int index, struct neigh_table *tbl); 305 int neigh_table_clear(int index, struct neigh_table *tbl); 306 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, 307 struct net_device *dev); 308 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net, 309 const void *pkey); 310 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey, 311 struct net_device *dev, bool want_ref); 312 static inline struct neighbour *neigh_create(struct neigh_table *tbl, 313 const void *pkey, 314 struct net_device *dev) 315 { 316 return __neigh_create(tbl, pkey, dev, true); 317 } 318 void neigh_destroy(struct neighbour *neigh); 319 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb); 320 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags, 321 u32 nlmsg_pid); 322 void __neigh_set_probe_once(struct neighbour *neigh); 323 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl); 324 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev); 325 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev); 326 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev); 327 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb); 328 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb); 329 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb); 330 struct neighbour *neigh_event_ns(struct neigh_table *tbl, 331 u8 *lladdr, void *saddr, 332 struct net_device *dev); 333 334 struct neigh_parms *neigh_parms_alloc(struct net_device *dev, 335 struct neigh_table *tbl); 336 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms); 337 338 static inline 339 struct net *neigh_parms_net(const struct neigh_parms *parms) 340 { 341 return read_pnet(&parms->net); 342 } 343 344 unsigned long neigh_rand_reach_time(unsigned long base); 345 346 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p, 347 struct sk_buff *skb); 348 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net, 349 const void *key, struct net_device *dev, 350 int creat); 351 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net, 352 const void *key, struct net_device *dev); 353 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, 354 struct net_device *dev); 355 356 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh) 357 { 358 return read_pnet(&pneigh->net); 359 } 360 361 void neigh_app_ns(struct neighbour *n); 362 void neigh_for_each(struct neigh_table *tbl, 363 void (*cb)(struct neighbour *, void *), void *cookie); 364 void __neigh_for_each_release(struct neigh_table *tbl, 365 int (*cb)(struct neighbour *)); 366 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *); 367 void pneigh_for_each(struct neigh_table *tbl, 368 void (*cb)(struct pneigh_entry *)); 369 370 struct neigh_seq_state { 371 struct seq_net_private p; 372 struct neigh_table *tbl; 373 struct neigh_hash_table *nht; 374 void *(*neigh_sub_iter)(struct neigh_seq_state *state, 375 struct neighbour *n, loff_t *pos); 376 unsigned int bucket; 377 unsigned int flags; 378 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001 379 #define NEIGH_SEQ_IS_PNEIGH 0x00000002 380 #define NEIGH_SEQ_SKIP_NOARP 0x00000004 381 }; 382 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, 383 unsigned int); 384 void *neigh_seq_next(struct seq_file *, void *, loff_t *); 385 void neigh_seq_stop(struct seq_file *, void *); 386 387 int neigh_proc_dointvec(struct ctl_table *ctl, int write, 388 void __user *buffer, size_t *lenp, loff_t *ppos); 389 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, 390 void __user *buffer, 391 size_t *lenp, loff_t *ppos); 392 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write, 393 void __user *buffer, 394 size_t *lenp, loff_t *ppos); 395 396 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p, 397 proc_handler *proc_handler); 398 void neigh_sysctl_unregister(struct neigh_parms *p); 399 400 static inline void __neigh_parms_put(struct neigh_parms *parms) 401 { 402 refcount_dec(&parms->refcnt); 403 } 404 405 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms) 406 { 407 refcount_inc(&parms->refcnt); 408 return parms; 409 } 410 411 /* 412 * Neighbour references 413 */ 414 415 static inline void neigh_release(struct neighbour *neigh) 416 { 417 if (refcount_dec_and_test(&neigh->refcnt)) 418 neigh_destroy(neigh); 419 } 420 421 static inline struct neighbour * neigh_clone(struct neighbour *neigh) 422 { 423 if (neigh) 424 refcount_inc(&neigh->refcnt); 425 return neigh; 426 } 427 428 #define neigh_hold(n) refcount_inc(&(n)->refcnt) 429 430 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb) 431 { 432 unsigned long now = jiffies; 433 434 if (neigh->used != now) 435 neigh->used = now; 436 if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE))) 437 return __neigh_event_send(neigh, skb); 438 return 0; 439 } 440 441 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 442 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb) 443 { 444 unsigned int seq, hh_alen; 445 446 do { 447 seq = read_seqbegin(&hh->hh_lock); 448 hh_alen = HH_DATA_ALIGN(ETH_HLEN); 449 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN); 450 } while (read_seqretry(&hh->hh_lock, seq)); 451 return 0; 452 } 453 #endif 454 455 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb) 456 { 457 unsigned int seq; 458 unsigned int hh_len; 459 460 do { 461 seq = read_seqbegin(&hh->hh_lock); 462 hh_len = hh->hh_len; 463 if (likely(hh_len <= HH_DATA_MOD)) { 464 /* this is inlined by gcc */ 465 memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD); 466 } else { 467 unsigned int hh_alen = HH_DATA_ALIGN(hh_len); 468 469 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); 470 } 471 } while (read_seqretry(&hh->hh_lock, seq)); 472 473 skb_push(skb, hh_len); 474 return dev_queue_xmit(skb); 475 } 476 477 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb) 478 { 479 const struct hh_cache *hh = &n->hh; 480 481 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len) 482 return neigh_hh_output(hh, skb); 483 else 484 return n->output(n, skb); 485 } 486 487 static inline struct neighbour * 488 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat) 489 { 490 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 491 492 if (n || !creat) 493 return n; 494 495 n = neigh_create(tbl, pkey, dev); 496 return IS_ERR(n) ? NULL : n; 497 } 498 499 static inline struct neighbour * 500 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey, 501 struct net_device *dev) 502 { 503 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 504 505 if (n) 506 return n; 507 508 return neigh_create(tbl, pkey, dev); 509 } 510 511 struct neighbour_cb { 512 unsigned long sched_next; 513 unsigned int flags; 514 }; 515 516 #define LOCALLY_ENQUEUED 0x1 517 518 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb) 519 520 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n, 521 const struct net_device *dev) 522 { 523 unsigned int seq; 524 525 do { 526 seq = read_seqbegin(&n->ha_lock); 527 memcpy(dst, n->ha, dev->addr_len); 528 } while (read_seqretry(&n->ha_lock, seq)); 529 } 530 531 static inline void neigh_update_ext_learned(struct neighbour *neigh, u32 flags, 532 int *notify) 533 { 534 u8 ndm_flags = 0; 535 536 if (!(flags & NEIGH_UPDATE_F_ADMIN)) 537 return; 538 539 ndm_flags |= (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0; 540 if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) { 541 if (ndm_flags & NTF_EXT_LEARNED) 542 neigh->flags |= NTF_EXT_LEARNED; 543 else 544 neigh->flags &= ~NTF_EXT_LEARNED; 545 *notify = 1; 546 } 547 } 548 549 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags, 550 int *notify) 551 { 552 u8 ndm_flags = 0; 553 554 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0; 555 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) { 556 if (ndm_flags & NTF_ROUTER) 557 neigh->flags |= NTF_ROUTER; 558 else 559 neigh->flags &= ~NTF_ROUTER; 560 *notify = 1; 561 } 562 } 563 #endif 564