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TOMOYO Linux Cross Reference
Linux/net/ipv4/inet_hashtables.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
  4  *              operating system.  INET is implemented using the BSD Socket
  5  *              interface as the means of communication with the user level.
  6  *
  7  *              Generic INET transport hashtables
  8  *
  9  * Authors:     Lotsa people, from code originally in tcp
 10  */
 11 
 12 #include <linux/module.h>
 13 #include <linux/random.h>
 14 #include <linux/sched.h>
 15 #include <linux/slab.h>
 16 #include <linux/wait.h>
 17 #include <linux/vmalloc.h>
 18 #include <linux/memblock.h>
 19 
 20 #include <net/addrconf.h>
 21 #include <net/inet_connection_sock.h>
 22 #include <net/inet_hashtables.h>
 23 #include <net/secure_seq.h>
 24 #include <net/ip.h>
 25 #include <net/tcp.h>
 26 #include <net/sock_reuseport.h>
 27 
 28 static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
 29                         const __u16 lport, const __be32 faddr,
 30                         const __be16 fport)
 31 {
 32         static u32 inet_ehash_secret __read_mostly;
 33 
 34         net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
 35 
 36         return __inet_ehashfn(laddr, lport, faddr, fport,
 37                               inet_ehash_secret + net_hash_mix(net));
 38 }
 39 
 40 /* This function handles inet_sock, but also timewait and request sockets
 41  * for IPv4/IPv6.
 42  */
 43 static u32 sk_ehashfn(const struct sock *sk)
 44 {
 45 #if IS_ENABLED(CONFIG_IPV6)
 46         if (sk->sk_family == AF_INET6 &&
 47             !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
 48                 return inet6_ehashfn(sock_net(sk),
 49                                      &sk->sk_v6_rcv_saddr, sk->sk_num,
 50                                      &sk->sk_v6_daddr, sk->sk_dport);
 51 #endif
 52         return inet_ehashfn(sock_net(sk),
 53                             sk->sk_rcv_saddr, sk->sk_num,
 54                             sk->sk_daddr, sk->sk_dport);
 55 }
 56 
 57 /*
 58  * Allocate and initialize a new local port bind bucket.
 59  * The bindhash mutex for snum's hash chain must be held here.
 60  */
 61 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
 62                                                  struct net *net,
 63                                                  struct inet_bind_hashbucket *head,
 64                                                  const unsigned short snum,
 65                                                  int l3mdev)
 66 {
 67         struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
 68 
 69         if (tb) {
 70                 write_pnet(&tb->ib_net, net);
 71                 tb->l3mdev    = l3mdev;
 72                 tb->port      = snum;
 73                 tb->fastreuse = 0;
 74                 tb->fastreuseport = 0;
 75                 INIT_HLIST_HEAD(&tb->owners);
 76                 hlist_add_head(&tb->node, &head->chain);
 77         }
 78         return tb;
 79 }
 80 
 81 /*
 82  * Caller must hold hashbucket lock for this tb with local BH disabled
 83  */
 84 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
 85 {
 86         if (hlist_empty(&tb->owners)) {
 87                 __hlist_del(&tb->node);
 88                 kmem_cache_free(cachep, tb);
 89         }
 90 }
 91 
 92 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
 93                     const unsigned short snum)
 94 {
 95         inet_sk(sk)->inet_num = snum;
 96         sk_add_bind_node(sk, &tb->owners);
 97         inet_csk(sk)->icsk_bind_hash = tb;
 98 }
 99 
100 /*
101  * Get rid of any references to a local port held by the given sock.
102  */
103 static void __inet_put_port(struct sock *sk)
104 {
105         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
106         const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
107                         hashinfo->bhash_size);
108         struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
109         struct inet_bind_bucket *tb;
110 
111         spin_lock(&head->lock);
112         tb = inet_csk(sk)->icsk_bind_hash;
113         __sk_del_bind_node(sk);
114         inet_csk(sk)->icsk_bind_hash = NULL;
115         inet_sk(sk)->inet_num = 0;
116         inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
117         spin_unlock(&head->lock);
118 }
119 
120 void inet_put_port(struct sock *sk)
121 {
122         local_bh_disable();
123         __inet_put_port(sk);
124         local_bh_enable();
125 }
126 EXPORT_SYMBOL(inet_put_port);
127 
128 int __inet_inherit_port(const struct sock *sk, struct sock *child)
129 {
130         struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
131         unsigned short port = inet_sk(child)->inet_num;
132         const int bhash = inet_bhashfn(sock_net(sk), port,
133                         table->bhash_size);
134         struct inet_bind_hashbucket *head = &table->bhash[bhash];
135         struct inet_bind_bucket *tb;
136         int l3mdev;
137 
138         spin_lock(&head->lock);
139         tb = inet_csk(sk)->icsk_bind_hash;
140         if (unlikely(!tb)) {
141                 spin_unlock(&head->lock);
142                 return -ENOENT;
143         }
144         if (tb->port != port) {
145                 l3mdev = inet_sk_bound_l3mdev(sk);
146 
147                 /* NOTE: using tproxy and redirecting skbs to a proxy
148                  * on a different listener port breaks the assumption
149                  * that the listener socket's icsk_bind_hash is the same
150                  * as that of the child socket. We have to look up or
151                  * create a new bind bucket for the child here. */
152                 inet_bind_bucket_for_each(tb, &head->chain) {
153                         if (net_eq(ib_net(tb), sock_net(sk)) &&
154                             tb->l3mdev == l3mdev && tb->port == port)
155                                 break;
156                 }
157                 if (!tb) {
158                         tb = inet_bind_bucket_create(table->bind_bucket_cachep,
159                                                      sock_net(sk), head, port,
160                                                      l3mdev);
161                         if (!tb) {
162                                 spin_unlock(&head->lock);
163                                 return -ENOMEM;
164                         }
165                 }
166         }
167         inet_bind_hash(child, tb, port);
168         spin_unlock(&head->lock);
169 
170         return 0;
171 }
172 EXPORT_SYMBOL_GPL(__inet_inherit_port);
173 
174 static struct inet_listen_hashbucket *
175 inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk)
176 {
177         u32 hash;
178 
179 #if IS_ENABLED(CONFIG_IPV6)
180         if (sk->sk_family == AF_INET6)
181                 hash = ipv6_portaddr_hash(sock_net(sk),
182                                           &sk->sk_v6_rcv_saddr,
183                                           inet_sk(sk)->inet_num);
184         else
185 #endif
186                 hash = ipv4_portaddr_hash(sock_net(sk),
187                                           inet_sk(sk)->inet_rcv_saddr,
188                                           inet_sk(sk)->inet_num);
189         return inet_lhash2_bucket(h, hash);
190 }
191 
192 static void inet_hash2(struct inet_hashinfo *h, struct sock *sk)
193 {
194         struct inet_listen_hashbucket *ilb2;
195 
196         if (!h->lhash2)
197                 return;
198 
199         ilb2 = inet_lhash2_bucket_sk(h, sk);
200 
201         spin_lock(&ilb2->lock);
202         if (sk->sk_reuseport && sk->sk_family == AF_INET6)
203                 hlist_add_tail_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
204                                    &ilb2->head);
205         else
206                 hlist_add_head_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
207                                    &ilb2->head);
208         ilb2->count++;
209         spin_unlock(&ilb2->lock);
210 }
211 
212 static void inet_unhash2(struct inet_hashinfo *h, struct sock *sk)
213 {
214         struct inet_listen_hashbucket *ilb2;
215 
216         if (!h->lhash2 ||
217             WARN_ON_ONCE(hlist_unhashed(&inet_csk(sk)->icsk_listen_portaddr_node)))
218                 return;
219 
220         ilb2 = inet_lhash2_bucket_sk(h, sk);
221 
222         spin_lock(&ilb2->lock);
223         hlist_del_init_rcu(&inet_csk(sk)->icsk_listen_portaddr_node);
224         ilb2->count--;
225         spin_unlock(&ilb2->lock);
226 }
227 
228 static inline int compute_score(struct sock *sk, struct net *net,
229                                 const unsigned short hnum, const __be32 daddr,
230                                 const int dif, const int sdif, bool exact_dif)
231 {
232         int score = -1;
233 
234         if (net_eq(sock_net(sk), net) && sk->sk_num == hnum &&
235                         !ipv6_only_sock(sk)) {
236                 if (sk->sk_rcv_saddr != daddr)
237                         return -1;
238 
239                 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
240                         return -1;
241 
242                 score = sk->sk_family == PF_INET ? 2 : 1;
243                 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
244                         score++;
245         }
246         return score;
247 }
248 
249 /*
250  * Here are some nice properties to exploit here. The BSD API
251  * does not allow a listening sock to specify the remote port nor the
252  * remote address for the connection. So always assume those are both
253  * wildcarded during the search since they can never be otherwise.
254  */
255 
256 /* called with rcu_read_lock() : No refcount taken on the socket */
257 static struct sock *inet_lhash2_lookup(struct net *net,
258                                 struct inet_listen_hashbucket *ilb2,
259                                 struct sk_buff *skb, int doff,
260                                 const __be32 saddr, __be16 sport,
261                                 const __be32 daddr, const unsigned short hnum,
262                                 const int dif, const int sdif)
263 {
264         bool exact_dif = inet_exact_dif_match(net, skb);
265         struct inet_connection_sock *icsk;
266         struct sock *sk, *result = NULL;
267         int score, hiscore = 0;
268         u32 phash = 0;
269 
270         inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
271                 sk = (struct sock *)icsk;
272                 score = compute_score(sk, net, hnum, daddr,
273                                       dif, sdif, exact_dif);
274                 if (score > hiscore) {
275                         if (sk->sk_reuseport) {
276                                 phash = inet_ehashfn(net, daddr, hnum,
277                                                      saddr, sport);
278                                 result = reuseport_select_sock(sk, phash,
279                                                                skb, doff);
280                                 if (result)
281                                         return result;
282                         }
283                         result = sk;
284                         hiscore = score;
285                 }
286         }
287 
288         return result;
289 }
290 
291 struct sock *__inet_lookup_listener(struct net *net,
292                                     struct inet_hashinfo *hashinfo,
293                                     struct sk_buff *skb, int doff,
294                                     const __be32 saddr, __be16 sport,
295                                     const __be32 daddr, const unsigned short hnum,
296                                     const int dif, const int sdif)
297 {
298         struct inet_listen_hashbucket *ilb2;
299         struct sock *result = NULL;
300         unsigned int hash2;
301 
302         hash2 = ipv4_portaddr_hash(net, daddr, hnum);
303         ilb2 = inet_lhash2_bucket(hashinfo, hash2);
304 
305         result = inet_lhash2_lookup(net, ilb2, skb, doff,
306                                     saddr, sport, daddr, hnum,
307                                     dif, sdif);
308         if (result)
309                 goto done;
310 
311         /* Lookup lhash2 with INADDR_ANY */
312         hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
313         ilb2 = inet_lhash2_bucket(hashinfo, hash2);
314 
315         result = inet_lhash2_lookup(net, ilb2, skb, doff,
316                                     saddr, sport, htonl(INADDR_ANY), hnum,
317                                     dif, sdif);
318 done:
319         if (IS_ERR(result))
320                 return NULL;
321         return result;
322 }
323 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
324 
325 /* All sockets share common refcount, but have different destructors */
326 void sock_gen_put(struct sock *sk)
327 {
328         if (!refcount_dec_and_test(&sk->sk_refcnt))
329                 return;
330 
331         if (sk->sk_state == TCP_TIME_WAIT)
332                 inet_twsk_free(inet_twsk(sk));
333         else if (sk->sk_state == TCP_NEW_SYN_RECV)
334                 reqsk_free(inet_reqsk(sk));
335         else
336                 sk_free(sk);
337 }
338 EXPORT_SYMBOL_GPL(sock_gen_put);
339 
340 void sock_edemux(struct sk_buff *skb)
341 {
342         sock_gen_put(skb->sk);
343 }
344 EXPORT_SYMBOL(sock_edemux);
345 
346 struct sock *__inet_lookup_established(struct net *net,
347                                   struct inet_hashinfo *hashinfo,
348                                   const __be32 saddr, const __be16 sport,
349                                   const __be32 daddr, const u16 hnum,
350                                   const int dif, const int sdif)
351 {
352         INET_ADDR_COOKIE(acookie, saddr, daddr);
353         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
354         struct sock *sk;
355         const struct hlist_nulls_node *node;
356         /* Optimize here for direct hit, only listening connections can
357          * have wildcards anyways.
358          */
359         unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
360         unsigned int slot = hash & hashinfo->ehash_mask;
361         struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
362 
363 begin:
364         sk_nulls_for_each_rcu(sk, node, &head->chain) {
365                 if (sk->sk_hash != hash)
366                         continue;
367                 if (likely(INET_MATCH(sk, net, acookie,
368                                       saddr, daddr, ports, dif, sdif))) {
369                         if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
370                                 goto out;
371                         if (unlikely(!INET_MATCH(sk, net, acookie,
372                                                  saddr, daddr, ports,
373                                                  dif, sdif))) {
374                                 sock_gen_put(sk);
375                                 goto begin;
376                         }
377                         goto found;
378                 }
379         }
380         /*
381          * if the nulls value we got at the end of this lookup is
382          * not the expected one, we must restart lookup.
383          * We probably met an item that was moved to another chain.
384          */
385         if (get_nulls_value(node) != slot)
386                 goto begin;
387 out:
388         sk = NULL;
389 found:
390         return sk;
391 }
392 EXPORT_SYMBOL_GPL(__inet_lookup_established);
393 
394 /* called with local bh disabled */
395 static int __inet_check_established(struct inet_timewait_death_row *death_row,
396                                     struct sock *sk, __u16 lport,
397                                     struct inet_timewait_sock **twp)
398 {
399         struct inet_hashinfo *hinfo = death_row->hashinfo;
400         struct inet_sock *inet = inet_sk(sk);
401         __be32 daddr = inet->inet_rcv_saddr;
402         __be32 saddr = inet->inet_daddr;
403         int dif = sk->sk_bound_dev_if;
404         struct net *net = sock_net(sk);
405         int sdif = l3mdev_master_ifindex_by_index(net, dif);
406         INET_ADDR_COOKIE(acookie, saddr, daddr);
407         const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
408         unsigned int hash = inet_ehashfn(net, daddr, lport,
409                                          saddr, inet->inet_dport);
410         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
411         spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
412         struct sock *sk2;
413         const struct hlist_nulls_node *node;
414         struct inet_timewait_sock *tw = NULL;
415 
416         spin_lock(lock);
417 
418         sk_nulls_for_each(sk2, node, &head->chain) {
419                 if (sk2->sk_hash != hash)
420                         continue;
421 
422                 if (likely(INET_MATCH(sk2, net, acookie,
423                                          saddr, daddr, ports, dif, sdif))) {
424                         if (sk2->sk_state == TCP_TIME_WAIT) {
425                                 tw = inet_twsk(sk2);
426                                 if (twsk_unique(sk, sk2, twp))
427                                         break;
428                         }
429                         goto not_unique;
430                 }
431         }
432 
433         /* Must record num and sport now. Otherwise we will see
434          * in hash table socket with a funny identity.
435          */
436         inet->inet_num = lport;
437         inet->inet_sport = htons(lport);
438         sk->sk_hash = hash;
439         WARN_ON(!sk_unhashed(sk));
440         __sk_nulls_add_node_rcu(sk, &head->chain);
441         if (tw) {
442                 sk_nulls_del_node_init_rcu((struct sock *)tw);
443                 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
444         }
445         spin_unlock(lock);
446         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
447 
448         if (twp) {
449                 *twp = tw;
450         } else if (tw) {
451                 /* Silly. Should hash-dance instead... */
452                 inet_twsk_deschedule_put(tw);
453         }
454         return 0;
455 
456 not_unique:
457         spin_unlock(lock);
458         return -EADDRNOTAVAIL;
459 }
460 
461 static u32 inet_sk_port_offset(const struct sock *sk)
462 {
463         const struct inet_sock *inet = inet_sk(sk);
464 
465         return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
466                                           inet->inet_daddr,
467                                           inet->inet_dport);
468 }
469 
470 /* insert a socket into ehash, and eventually remove another one
471  * (The another one can be a SYN_RECV or TIMEWAIT
472  */
473 bool inet_ehash_insert(struct sock *sk, struct sock *osk)
474 {
475         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
476         struct hlist_nulls_head *list;
477         struct inet_ehash_bucket *head;
478         spinlock_t *lock;
479         bool ret = true;
480 
481         WARN_ON_ONCE(!sk_unhashed(sk));
482 
483         sk->sk_hash = sk_ehashfn(sk);
484         head = inet_ehash_bucket(hashinfo, sk->sk_hash);
485         list = &head->chain;
486         lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
487 
488         spin_lock(lock);
489         if (osk) {
490                 WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
491                 ret = sk_nulls_del_node_init_rcu(osk);
492         }
493         if (ret)
494                 __sk_nulls_add_node_rcu(sk, list);
495         spin_unlock(lock);
496         return ret;
497 }
498 
499 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
500 {
501         bool ok = inet_ehash_insert(sk, osk);
502 
503         if (ok) {
504                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
505         } else {
506                 percpu_counter_inc(sk->sk_prot->orphan_count);
507                 inet_sk_set_state(sk, TCP_CLOSE);
508                 sock_set_flag(sk, SOCK_DEAD);
509                 inet_csk_destroy_sock(sk);
510         }
511         return ok;
512 }
513 EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
514 
515 static int inet_reuseport_add_sock(struct sock *sk,
516                                    struct inet_listen_hashbucket *ilb)
517 {
518         struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
519         const struct hlist_nulls_node *node;
520         struct sock *sk2;
521         kuid_t uid = sock_i_uid(sk);
522 
523         sk_nulls_for_each_rcu(sk2, node, &ilb->nulls_head) {
524                 if (sk2 != sk &&
525                     sk2->sk_family == sk->sk_family &&
526                     ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
527                     sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
528                     inet_csk(sk2)->icsk_bind_hash == tb &&
529                     sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
530                     inet_rcv_saddr_equal(sk, sk2, false))
531                         return reuseport_add_sock(sk, sk2,
532                                                   inet_rcv_saddr_any(sk));
533         }
534 
535         return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
536 }
537 
538 int __inet_hash(struct sock *sk, struct sock *osk)
539 {
540         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
541         struct inet_listen_hashbucket *ilb;
542         int err = 0;
543 
544         if (sk->sk_state != TCP_LISTEN) {
545                 inet_ehash_nolisten(sk, osk);
546                 return 0;
547         }
548         WARN_ON(!sk_unhashed(sk));
549         ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
550 
551         spin_lock(&ilb->lock);
552         if (sk->sk_reuseport) {
553                 err = inet_reuseport_add_sock(sk, ilb);
554                 if (err)
555                         goto unlock;
556         }
557         if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
558                 sk->sk_family == AF_INET6)
559                 __sk_nulls_add_node_tail_rcu(sk, &ilb->nulls_head);
560         else
561                 __sk_nulls_add_node_rcu(sk, &ilb->nulls_head);
562         inet_hash2(hashinfo, sk);
563         ilb->count++;
564         sock_set_flag(sk, SOCK_RCU_FREE);
565         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
566 unlock:
567         spin_unlock(&ilb->lock);
568 
569         return err;
570 }
571 EXPORT_SYMBOL(__inet_hash);
572 
573 int inet_hash(struct sock *sk)
574 {
575         int err = 0;
576 
577         if (sk->sk_state != TCP_CLOSE) {
578                 local_bh_disable();
579                 err = __inet_hash(sk, NULL);
580                 local_bh_enable();
581         }
582 
583         return err;
584 }
585 EXPORT_SYMBOL_GPL(inet_hash);
586 
587 void inet_unhash(struct sock *sk)
588 {
589         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
590         struct inet_listen_hashbucket *ilb = NULL;
591         spinlock_t *lock;
592 
593         if (sk_unhashed(sk))
594                 return;
595 
596         if (sk->sk_state == TCP_LISTEN) {
597                 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
598                 lock = &ilb->lock;
599         } else {
600                 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
601         }
602         spin_lock_bh(lock);
603         if (sk_unhashed(sk))
604                 goto unlock;
605 
606         if (rcu_access_pointer(sk->sk_reuseport_cb))
607                 reuseport_detach_sock(sk);
608         if (ilb) {
609                 inet_unhash2(hashinfo, sk);
610                 ilb->count--;
611         }
612         __sk_nulls_del_node_init_rcu(sk);
613         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
614 unlock:
615         spin_unlock_bh(lock);
616 }
617 EXPORT_SYMBOL_GPL(inet_unhash);
618 
619 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
620                 struct sock *sk, u32 port_offset,
621                 int (*check_established)(struct inet_timewait_death_row *,
622                         struct sock *, __u16, struct inet_timewait_sock **))
623 {
624         struct inet_hashinfo *hinfo = death_row->hashinfo;
625         struct inet_timewait_sock *tw = NULL;
626         struct inet_bind_hashbucket *head;
627         int port = inet_sk(sk)->inet_num;
628         struct net *net = sock_net(sk);
629         struct inet_bind_bucket *tb;
630         u32 remaining, offset;
631         int ret, i, low, high;
632         static u32 hint;
633         int l3mdev;
634 
635         if (port) {
636                 head = &hinfo->bhash[inet_bhashfn(net, port,
637                                                   hinfo->bhash_size)];
638                 tb = inet_csk(sk)->icsk_bind_hash;
639                 spin_lock_bh(&head->lock);
640                 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
641                         inet_ehash_nolisten(sk, NULL);
642                         spin_unlock_bh(&head->lock);
643                         return 0;
644                 }
645                 spin_unlock(&head->lock);
646                 /* No definite answer... Walk to established hash table */
647                 ret = check_established(death_row, sk, port, NULL);
648                 local_bh_enable();
649                 return ret;
650         }
651 
652         l3mdev = inet_sk_bound_l3mdev(sk);
653 
654         inet_get_local_port_range(net, &low, &high);
655         high++; /* [32768, 60999] -> [32768, 61000[ */
656         remaining = high - low;
657         if (likely(remaining > 1))
658                 remaining &= ~1U;
659 
660         offset = (hint + port_offset) % remaining;
661         /* In first pass we try ports of @low parity.
662          * inet_csk_get_port() does the opposite choice.
663          */
664         offset &= ~1U;
665 other_parity_scan:
666         port = low + offset;
667         for (i = 0; i < remaining; i += 2, port += 2) {
668                 if (unlikely(port >= high))
669                         port -= remaining;
670                 if (inet_is_local_reserved_port(net, port))
671                         continue;
672                 head = &hinfo->bhash[inet_bhashfn(net, port,
673                                                   hinfo->bhash_size)];
674                 spin_lock_bh(&head->lock);
675 
676                 /* Does not bother with rcv_saddr checks, because
677                  * the established check is already unique enough.
678                  */
679                 inet_bind_bucket_for_each(tb, &head->chain) {
680                         if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
681                             tb->port == port) {
682                                 if (tb->fastreuse >= 0 ||
683                                     tb->fastreuseport >= 0)
684                                         goto next_port;
685                                 WARN_ON(hlist_empty(&tb->owners));
686                                 if (!check_established(death_row, sk,
687                                                        port, &tw))
688                                         goto ok;
689                                 goto next_port;
690                         }
691                 }
692 
693                 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
694                                              net, head, port, l3mdev);
695                 if (!tb) {
696                         spin_unlock_bh(&head->lock);
697                         return -ENOMEM;
698                 }
699                 tb->fastreuse = -1;
700                 tb->fastreuseport = -1;
701                 goto ok;
702 next_port:
703                 spin_unlock_bh(&head->lock);
704                 cond_resched();
705         }
706 
707         offset++;
708         if ((offset & 1) && remaining > 1)
709                 goto other_parity_scan;
710 
711         return -EADDRNOTAVAIL;
712 
713 ok:
714         hint += i + 2;
715 
716         /* Head lock still held and bh's disabled */
717         inet_bind_hash(sk, tb, port);
718         if (sk_unhashed(sk)) {
719                 inet_sk(sk)->inet_sport = htons(port);
720                 inet_ehash_nolisten(sk, (struct sock *)tw);
721         }
722         if (tw)
723                 inet_twsk_bind_unhash(tw, hinfo);
724         spin_unlock(&head->lock);
725         if (tw)
726                 inet_twsk_deschedule_put(tw);
727         local_bh_enable();
728         return 0;
729 }
730 
731 /*
732  * Bind a port for a connect operation and hash it.
733  */
734 int inet_hash_connect(struct inet_timewait_death_row *death_row,
735                       struct sock *sk)
736 {
737         u32 port_offset = 0;
738 
739         if (!inet_sk(sk)->inet_num)
740                 port_offset = inet_sk_port_offset(sk);
741         return __inet_hash_connect(death_row, sk, port_offset,
742                                    __inet_check_established);
743 }
744 EXPORT_SYMBOL_GPL(inet_hash_connect);
745 
746 void inet_hashinfo_init(struct inet_hashinfo *h)
747 {
748         int i;
749 
750         for (i = 0; i < INET_LHTABLE_SIZE; i++) {
751                 spin_lock_init(&h->listening_hash[i].lock);
752                 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].nulls_head,
753                                       i + LISTENING_NULLS_BASE);
754                 h->listening_hash[i].count = 0;
755         }
756 
757         h->lhash2 = NULL;
758 }
759 EXPORT_SYMBOL_GPL(inet_hashinfo_init);
760 
761 static void init_hashinfo_lhash2(struct inet_hashinfo *h)
762 {
763         int i;
764 
765         for (i = 0; i <= h->lhash2_mask; i++) {
766                 spin_lock_init(&h->lhash2[i].lock);
767                 INIT_HLIST_HEAD(&h->lhash2[i].head);
768                 h->lhash2[i].count = 0;
769         }
770 }
771 
772 void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
773                                 unsigned long numentries, int scale,
774                                 unsigned long low_limit,
775                                 unsigned long high_limit)
776 {
777         h->lhash2 = alloc_large_system_hash(name,
778                                             sizeof(*h->lhash2),
779                                             numentries,
780                                             scale,
781                                             0,
782                                             NULL,
783                                             &h->lhash2_mask,
784                                             low_limit,
785                                             high_limit);
786         init_hashinfo_lhash2(h);
787 }
788 
789 int inet_hashinfo2_init_mod(struct inet_hashinfo *h)
790 {
791         h->lhash2 = kmalloc_array(INET_LHTABLE_SIZE, sizeof(*h->lhash2), GFP_KERNEL);
792         if (!h->lhash2)
793                 return -ENOMEM;
794 
795         h->lhash2_mask = INET_LHTABLE_SIZE - 1;
796         /* INET_LHTABLE_SIZE must be a power of 2 */
797         BUG_ON(INET_LHTABLE_SIZE & h->lhash2_mask);
798 
799         init_hashinfo_lhash2(h);
800         return 0;
801 }
802 EXPORT_SYMBOL_GPL(inet_hashinfo2_init_mod);
803 
804 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
805 {
806         unsigned int locksz = sizeof(spinlock_t);
807         unsigned int i, nblocks = 1;
808 
809         if (locksz != 0) {
810                 /* allocate 2 cache lines or at least one spinlock per cpu */
811                 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
812                 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
813 
814                 /* no more locks than number of hash buckets */
815                 nblocks = min(nblocks, hashinfo->ehash_mask + 1);
816 
817                 hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
818                 if (!hashinfo->ehash_locks)
819                         return -ENOMEM;
820 
821                 for (i = 0; i < nblocks; i++)
822                         spin_lock_init(&hashinfo->ehash_locks[i]);
823         }
824         hashinfo->ehash_locks_mask = nblocks - 1;
825         return 0;
826 }
827 EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);
828 

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