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_resolve_output(struct neighbour *neigh, struct sk_buff *skb); 327 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb); 328 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb); 329 struct neighbour *neigh_event_ns(struct neigh_table *tbl, 330 u8 *lladdr, void *saddr, 331 struct net_device *dev); 332 333 struct neigh_parms *neigh_parms_alloc(struct net_device *dev, 334 struct neigh_table *tbl); 335 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms); 336 337 static inline 338 struct net *neigh_parms_net(const struct neigh_parms *parms) 339 { 340 return read_pnet(&parms->net); 341 } 342 343 unsigned long neigh_rand_reach_time(unsigned long base); 344 345 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p, 346 struct sk_buff *skb); 347 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net, 348 const void *key, struct net_device *dev, 349 int creat); 350 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net, 351 const void *key, struct net_device *dev); 352 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, 353 struct net_device *dev); 354 355 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh) 356 { 357 return read_pnet(&pneigh->net); 358 } 359 360 void neigh_app_ns(struct neighbour *n); 361 void neigh_for_each(struct neigh_table *tbl, 362 void (*cb)(struct neighbour *, void *), void *cookie); 363 void __neigh_for_each_release(struct neigh_table *tbl, 364 int (*cb)(struct neighbour *)); 365 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *); 366 void pneigh_for_each(struct neigh_table *tbl, 367 void (*cb)(struct pneigh_entry *)); 368 369 struct neigh_seq_state { 370 struct seq_net_private p; 371 struct neigh_table *tbl; 372 struct neigh_hash_table *nht; 373 void *(*neigh_sub_iter)(struct neigh_seq_state *state, 374 struct neighbour *n, loff_t *pos); 375 unsigned int bucket; 376 unsigned int flags; 377 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001 378 #define NEIGH_SEQ_IS_PNEIGH 0x00000002 379 #define NEIGH_SEQ_SKIP_NOARP 0x00000004 380 }; 381 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, 382 unsigned int); 383 void *neigh_seq_next(struct seq_file *, void *, loff_t *); 384 void neigh_seq_stop(struct seq_file *, void *); 385 386 int neigh_proc_dointvec(struct ctl_table *ctl, int write, 387 void __user *buffer, size_t *lenp, loff_t *ppos); 388 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, 389 void __user *buffer, 390 size_t *lenp, loff_t *ppos); 391 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write, 392 void __user *buffer, 393 size_t *lenp, loff_t *ppos); 394 395 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p, 396 proc_handler *proc_handler); 397 void neigh_sysctl_unregister(struct neigh_parms *p); 398 399 static inline void __neigh_parms_put(struct neigh_parms *parms) 400 { 401 refcount_dec(&parms->refcnt); 402 } 403 404 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms) 405 { 406 refcount_inc(&parms->refcnt); 407 return parms; 408 } 409 410 /* 411 * Neighbour references 412 */ 413 414 static inline void neigh_release(struct neighbour *neigh) 415 { 416 if (refcount_dec_and_test(&neigh->refcnt)) 417 neigh_destroy(neigh); 418 } 419 420 static inline struct neighbour * neigh_clone(struct neighbour *neigh) 421 { 422 if (neigh) 423 refcount_inc(&neigh->refcnt); 424 return neigh; 425 } 426 427 #define neigh_hold(n) refcount_inc(&(n)->refcnt) 428 429 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb) 430 { 431 unsigned long now = jiffies; 432 433 if (neigh->used != now) 434 neigh->used = now; 435 if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE))) 436 return __neigh_event_send(neigh, skb); 437 return 0; 438 } 439 440 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 441 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb) 442 { 443 unsigned int seq, hh_alen; 444 445 do { 446 seq = read_seqbegin(&hh->hh_lock); 447 hh_alen = HH_DATA_ALIGN(ETH_HLEN); 448 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN); 449 } while (read_seqretry(&hh->hh_lock, seq)); 450 return 0; 451 } 452 #endif 453 454 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb) 455 { 456 unsigned int seq; 457 unsigned int hh_len; 458 459 do { 460 seq = read_seqbegin(&hh->hh_lock); 461 hh_len = hh->hh_len; 462 if (likely(hh_len <= HH_DATA_MOD)) { 463 /* this is inlined by gcc */ 464 memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD); 465 } else { 466 unsigned int hh_alen = HH_DATA_ALIGN(hh_len); 467 468 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); 469 } 470 } while (read_seqretry(&hh->hh_lock, seq)); 471 472 skb_push(skb, hh_len); 473 return dev_queue_xmit(skb); 474 } 475 476 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb) 477 { 478 const struct hh_cache *hh = &n->hh; 479 480 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len) 481 return neigh_hh_output(hh, skb); 482 else 483 return n->output(n, skb); 484 } 485 486 static inline struct neighbour * 487 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat) 488 { 489 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 490 491 if (n || !creat) 492 return n; 493 494 n = neigh_create(tbl, pkey, dev); 495 return IS_ERR(n) ? NULL : n; 496 } 497 498 static inline struct neighbour * 499 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey, 500 struct net_device *dev) 501 { 502 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 503 504 if (n) 505 return n; 506 507 return neigh_create(tbl, pkey, dev); 508 } 509 510 struct neighbour_cb { 511 unsigned long sched_next; 512 unsigned int flags; 513 }; 514 515 #define LOCALLY_ENQUEUED 0x1 516 517 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb) 518 519 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n, 520 const struct net_device *dev) 521 { 522 unsigned int seq; 523 524 do { 525 seq = read_seqbegin(&n->ha_lock); 526 memcpy(dst, n->ha, dev->addr_len); 527 } while (read_seqretry(&n->ha_lock, seq)); 528 } 529 530 static inline void neigh_update_ext_learned(struct neighbour *neigh, u32 flags, 531 int *notify) 532 { 533 u8 ndm_flags = 0; 534 535 if (!(flags & NEIGH_UPDATE_F_ADMIN)) 536 return; 537 538 ndm_flags |= (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0; 539 if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) { 540 if (ndm_flags & NTF_EXT_LEARNED) 541 neigh->flags |= NTF_EXT_LEARNED; 542 else 543 neigh->flags &= ~NTF_EXT_LEARNED; 544 *notify = 1; 545 } 546 } 547 #endif 548