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 struct neigh_table *tbl; 76 77 void *sysctl_table; 78 79 int dead; 80 refcount_t refcnt; 81 struct rcu_head rcu_head; 82 83 int reachable_time; 84 int data[NEIGH_VAR_DATA_MAX]; 85 DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX); 86 }; 87 88 static inline void neigh_var_set(struct neigh_parms *p, int index, int val) 89 { 90 set_bit(index, p->data_state); 91 p->data[index] = val; 92 } 93 94 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr]) 95 96 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used. 97 * In other cases, NEIGH_VAR_SET should be used. 98 */ 99 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val) 100 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val) 101 102 static inline void neigh_parms_data_state_setall(struct neigh_parms *p) 103 { 104 bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX); 105 } 106 107 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p) 108 { 109 bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX); 110 } 111 112 struct neigh_statistics { 113 unsigned long allocs; /* number of allocated neighs */ 114 unsigned long destroys; /* number of destroyed neighs */ 115 unsigned long hash_grows; /* number of hash resizes */ 116 117 unsigned long res_failed; /* number of failed resolutions */ 118 119 unsigned long lookups; /* number of lookups */ 120 unsigned long hits; /* number of hits (among lookups) */ 121 122 unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */ 123 unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */ 124 125 unsigned long periodic_gc_runs; /* number of periodic GC runs */ 126 unsigned long forced_gc_runs; /* number of forced GC runs */ 127 128 unsigned long unres_discards; /* number of unresolved drops */ 129 unsigned long table_fulls; /* times even gc couldn't help */ 130 }; 131 132 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field) 133 134 struct neighbour { 135 struct neighbour __rcu *next; 136 struct neigh_table *tbl; 137 struct neigh_parms *parms; 138 unsigned long confirmed; 139 unsigned long updated; 140 rwlock_t lock; 141 refcount_t refcnt; 142 unsigned int arp_queue_len_bytes; 143 struct sk_buff_head arp_queue; 144 struct timer_list timer; 145 unsigned long used; 146 atomic_t probes; 147 __u8 flags; 148 __u8 nud_state; 149 __u8 type; 150 __u8 dead; 151 u8 protocol; 152 seqlock_t ha_lock; 153 unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8); 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 protocol; 177 u8 key[]; 178 }; 179 180 /* 181 * neighbour table manipulation 182 */ 183 184 #define NEIGH_NUM_HASH_RND 4 185 186 struct neigh_hash_table { 187 struct neighbour __rcu **hash_buckets; 188 unsigned int hash_shift; 189 __u32 hash_rnd[NEIGH_NUM_HASH_RND]; 190 struct rcu_head rcu; 191 }; 192 193 194 struct neigh_table { 195 int family; 196 unsigned int entry_size; 197 unsigned int key_len; 198 __be16 protocol; 199 __u32 (*hash)(const void *pkey, 200 const struct net_device *dev, 201 __u32 *hash_rnd); 202 bool (*key_eq)(const struct neighbour *, const void *pkey); 203 int (*constructor)(struct neighbour *); 204 int (*pconstructor)(struct pneigh_entry *); 205 void (*pdestructor)(struct pneigh_entry *); 206 void (*proxy_redo)(struct sk_buff *skb); 207 int (*is_multicast)(const void *pkey); 208 bool (*allow_add)(const struct net_device *dev, 209 struct netlink_ext_ack *extack); 210 char *id; 211 struct neigh_parms parms; 212 struct list_head parms_list; 213 int gc_interval; 214 int gc_thresh1; 215 int gc_thresh2; 216 int gc_thresh3; 217 unsigned long last_flush; 218 struct delayed_work gc_work; 219 struct timer_list proxy_timer; 220 struct sk_buff_head proxy_queue; 221 atomic_t entries; 222 atomic_t gc_entries; 223 struct list_head gc_list; 224 rwlock_t lock; 225 unsigned long last_rand; 226 struct neigh_statistics __percpu *stats; 227 struct neigh_hash_table __rcu *nht; 228 struct pneigh_entry **phash_buckets; 229 }; 230 231 enum { 232 NEIGH_ARP_TABLE = 0, 233 NEIGH_ND_TABLE = 1, 234 NEIGH_DN_TABLE = 2, 235 NEIGH_NR_TABLES, 236 NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */ 237 }; 238 239 static inline int neigh_parms_family(struct neigh_parms *p) 240 { 241 return p->tbl->family; 242 } 243 244 #define NEIGH_PRIV_ALIGN sizeof(long long) 245 #define NEIGH_ENTRY_SIZE(size) ALIGN((size), NEIGH_PRIV_ALIGN) 246 247 static inline void *neighbour_priv(const struct neighbour *n) 248 { 249 return (char *)n + n->tbl->entry_size; 250 } 251 252 /* flags for neigh_update() */ 253 #define NEIGH_UPDATE_F_OVERRIDE 0x00000001 254 #define NEIGH_UPDATE_F_WEAK_OVERRIDE 0x00000002 255 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER 0x00000004 256 #define NEIGH_UPDATE_F_EXT_LEARNED 0x20000000 257 #define NEIGH_UPDATE_F_ISROUTER 0x40000000 258 #define NEIGH_UPDATE_F_ADMIN 0x80000000 259 260 extern const struct nla_policy nda_policy[]; 261 262 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey) 263 { 264 return *(const u16 *)n->primary_key == *(const u16 *)pkey; 265 } 266 267 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey) 268 { 269 return *(const u32 *)n->primary_key == *(const u32 *)pkey; 270 } 271 272 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey) 273 { 274 const u32 *n32 = (const u32 *)n->primary_key; 275 const u32 *p32 = pkey; 276 277 return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) | 278 (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0; 279 } 280 281 static inline struct neighbour *___neigh_lookup_noref( 282 struct neigh_table *tbl, 283 bool (*key_eq)(const struct neighbour *n, const void *pkey), 284 __u32 (*hash)(const void *pkey, 285 const struct net_device *dev, 286 __u32 *hash_rnd), 287 const void *pkey, 288 struct net_device *dev) 289 { 290 struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht); 291 struct neighbour *n; 292 u32 hash_val; 293 294 hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift); 295 for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]); 296 n != NULL; 297 n = rcu_dereference_bh(n->next)) { 298 if (n->dev == dev && key_eq(n, pkey)) 299 return n; 300 } 301 302 return NULL; 303 } 304 305 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl, 306 const void *pkey, 307 struct net_device *dev) 308 { 309 return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev); 310 } 311 312 void neigh_table_init(int index, struct neigh_table *tbl); 313 int neigh_table_clear(int index, struct neigh_table *tbl); 314 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, 315 struct net_device *dev); 316 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net, 317 const void *pkey); 318 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey, 319 struct net_device *dev, bool want_ref); 320 static inline struct neighbour *neigh_create(struct neigh_table *tbl, 321 const void *pkey, 322 struct net_device *dev) 323 { 324 return __neigh_create(tbl, pkey, dev, true); 325 } 326 void neigh_destroy(struct neighbour *neigh); 327 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb); 328 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags, 329 u32 nlmsg_pid); 330 void __neigh_set_probe_once(struct neighbour *neigh); 331 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl); 332 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev); 333 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev); 334 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev); 335 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb); 336 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb); 337 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb); 338 struct neighbour *neigh_event_ns(struct neigh_table *tbl, 339 u8 *lladdr, void *saddr, 340 struct net_device *dev); 341 342 struct neigh_parms *neigh_parms_alloc(struct net_device *dev, 343 struct neigh_table *tbl); 344 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms); 345 346 static inline 347 struct net *neigh_parms_net(const struct neigh_parms *parms) 348 { 349 return read_pnet(&parms->net); 350 } 351 352 unsigned long neigh_rand_reach_time(unsigned long base); 353 354 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p, 355 struct sk_buff *skb); 356 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net, 357 const void *key, struct net_device *dev, 358 int creat); 359 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net, 360 const void *key, struct net_device *dev); 361 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, 362 struct net_device *dev); 363 364 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh) 365 { 366 return read_pnet(&pneigh->net); 367 } 368 369 void neigh_app_ns(struct neighbour *n); 370 void neigh_for_each(struct neigh_table *tbl, 371 void (*cb)(struct neighbour *, void *), void *cookie); 372 void __neigh_for_each_release(struct neigh_table *tbl, 373 int (*cb)(struct neighbour *)); 374 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *); 375 void pneigh_for_each(struct neigh_table *tbl, 376 void (*cb)(struct pneigh_entry *)); 377 378 struct neigh_seq_state { 379 struct seq_net_private p; 380 struct neigh_table *tbl; 381 struct neigh_hash_table *nht; 382 void *(*neigh_sub_iter)(struct neigh_seq_state *state, 383 struct neighbour *n, loff_t *pos); 384 unsigned int bucket; 385 unsigned int flags; 386 #define NEIGH_SEQ_NEIGH_ONLY 0x00000001 387 #define NEIGH_SEQ_IS_PNEIGH 0x00000002 388 #define NEIGH_SEQ_SKIP_NOARP 0x00000004 389 }; 390 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *, 391 unsigned int); 392 void *neigh_seq_next(struct seq_file *, void *, loff_t *); 393 void neigh_seq_stop(struct seq_file *, void *); 394 395 int neigh_proc_dointvec(struct ctl_table *ctl, int write, 396 void *buffer, size_t *lenp, loff_t *ppos); 397 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, 398 void *buffer, 399 size_t *lenp, loff_t *ppos); 400 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write, 401 void *buffer, size_t *lenp, loff_t *ppos); 402 403 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p, 404 proc_handler *proc_handler); 405 void neigh_sysctl_unregister(struct neigh_parms *p); 406 407 static inline void __neigh_parms_put(struct neigh_parms *parms) 408 { 409 refcount_dec(&parms->refcnt); 410 } 411 412 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms) 413 { 414 refcount_inc(&parms->refcnt); 415 return parms; 416 } 417 418 /* 419 * Neighbour references 420 */ 421 422 static inline void neigh_release(struct neighbour *neigh) 423 { 424 if (refcount_dec_and_test(&neigh->refcnt)) 425 neigh_destroy(neigh); 426 } 427 428 static inline struct neighbour * neigh_clone(struct neighbour *neigh) 429 { 430 if (neigh) 431 refcount_inc(&neigh->refcnt); 432 return neigh; 433 } 434 435 #define neigh_hold(n) refcount_inc(&(n)->refcnt) 436 437 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb) 438 { 439 unsigned long now = jiffies; 440 441 if (READ_ONCE(neigh->used) != now) 442 WRITE_ONCE(neigh->used, now); 443 if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE))) 444 return __neigh_event_send(neigh, skb); 445 return 0; 446 } 447 448 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 449 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb) 450 { 451 unsigned int seq, hh_alen; 452 453 do { 454 seq = read_seqbegin(&hh->hh_lock); 455 hh_alen = HH_DATA_ALIGN(ETH_HLEN); 456 memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN); 457 } while (read_seqretry(&hh->hh_lock, seq)); 458 return 0; 459 } 460 #endif 461 462 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb) 463 { 464 unsigned int hh_alen = 0; 465 unsigned int seq; 466 unsigned int hh_len; 467 468 do { 469 seq = read_seqbegin(&hh->hh_lock); 470 hh_len = READ_ONCE(hh->hh_len); 471 if (likely(hh_len <= HH_DATA_MOD)) { 472 hh_alen = HH_DATA_MOD; 473 474 /* skb_push() would proceed silently if we have room for 475 * the unaligned size but not for the aligned size: 476 * check headroom explicitly. 477 */ 478 if (likely(skb_headroom(skb) >= HH_DATA_MOD)) { 479 /* this is inlined by gcc */ 480 memcpy(skb->data - HH_DATA_MOD, hh->hh_data, 481 HH_DATA_MOD); 482 } 483 } else { 484 hh_alen = HH_DATA_ALIGN(hh_len); 485 486 if (likely(skb_headroom(skb) >= hh_alen)) { 487 memcpy(skb->data - hh_alen, hh->hh_data, 488 hh_alen); 489 } 490 } 491 } while (read_seqretry(&hh->hh_lock, seq)); 492 493 if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) { 494 kfree_skb(skb); 495 return NET_XMIT_DROP; 496 } 497 498 __skb_push(skb, hh_len); 499 return dev_queue_xmit(skb); 500 } 501 502 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb, 503 bool skip_cache) 504 { 505 const struct hh_cache *hh = &n->hh; 506 507 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len && !skip_cache) 508 return neigh_hh_output(hh, skb); 509 else 510 return n->output(n, skb); 511 } 512 513 static inline struct neighbour * 514 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat) 515 { 516 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 517 518 if (n || !creat) 519 return n; 520 521 n = neigh_create(tbl, pkey, dev); 522 return IS_ERR(n) ? NULL : n; 523 } 524 525 static inline struct neighbour * 526 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey, 527 struct net_device *dev) 528 { 529 struct neighbour *n = neigh_lookup(tbl, pkey, dev); 530 531 if (n) 532 return n; 533 534 return neigh_create(tbl, pkey, dev); 535 } 536 537 struct neighbour_cb { 538 unsigned long sched_next; 539 unsigned int flags; 540 }; 541 542 #define LOCALLY_ENQUEUED 0x1 543 544 #define NEIGH_CB(skb) ((struct neighbour_cb *)(skb)->cb) 545 546 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n, 547 const struct net_device *dev) 548 { 549 unsigned int seq; 550 551 do { 552 seq = read_seqbegin(&n->ha_lock); 553 memcpy(dst, n->ha, dev->addr_len); 554 } while (read_seqretry(&n->ha_lock, seq)); 555 } 556 557 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags, 558 int *notify) 559 { 560 u8 ndm_flags = 0; 561 562 ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0; 563 if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) { 564 if (ndm_flags & NTF_ROUTER) 565 neigh->flags |= NTF_ROUTER; 566 else 567 neigh->flags &= ~NTF_ROUTER; 568 *notify = 1; 569 } 570 } 571 #endif 572