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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#if IS_ENABLED(CONFIG_IPV6)
24#include <net/inet6_hashtables.h>
25#endif
26#include <net/secure_seq.h>
27#include <net/ip.h>
28#include <net/tcp.h>
29#include <net/sock_reuseport.h>
30
31static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
32 const __u16 lport, const __be32 faddr,
33 const __be16 fport)
34{
35 static u32 inet_ehash_secret __read_mostly;
36
37 net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
38
39 return __inet_ehashfn(laddr, lport, faddr, fport,
40 inet_ehash_secret + net_hash_mix(net));
41}
42
43/* This function handles inet_sock, but also timewait and request sockets
44 * for IPv4/IPv6.
45 */
46static u32 sk_ehashfn(const struct sock *sk)
47{
48#if IS_ENABLED(CONFIG_IPV6)
49 if (sk->sk_family == AF_INET6 &&
50 !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
51 return inet6_ehashfn(sock_net(sk),
52 &sk->sk_v6_rcv_saddr, sk->sk_num,
53 &sk->sk_v6_daddr, sk->sk_dport);
54#endif
55 return inet_ehashfn(sock_net(sk),
56 sk->sk_rcv_saddr, sk->sk_num,
57 sk->sk_daddr, sk->sk_dport);
58}
59
60/*
61 * Allocate and initialize a new local port bind bucket.
62 * The bindhash mutex for snum's hash chain must be held here.
63 */
64struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
65 struct net *net,
66 struct inet_bind_hashbucket *head,
67 const unsigned short snum,
68 int l3mdev)
69{
70 struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
71
72 if (tb) {
73 write_pnet(&tb->ib_net, net);
74 tb->l3mdev = l3mdev;
75 tb->port = snum;
76 tb->fastreuse = 0;
77 tb->fastreuseport = 0;
78 INIT_HLIST_HEAD(&tb->owners);
79 hlist_add_head(&tb->node, &head->chain);
80 }
81 return tb;
82}
83
84/*
85 * Caller must hold hashbucket lock for this tb with local BH disabled
86 */
87void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
88{
89 if (hlist_empty(&tb->owners)) {
90 __hlist_del(&tb->node);
91 kmem_cache_free(cachep, tb);
92 }
93}
94
95void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
96 const unsigned short snum)
97{
98 inet_sk(sk)->inet_num = snum;
99 sk_add_bind_node(sk, &tb->owners);
100 inet_csk(sk)->icsk_bind_hash = tb;
101}
102
103/*
104 * Get rid of any references to a local port held by the given sock.
105 */
106static void __inet_put_port(struct sock *sk)
107{
108 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
109 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
110 hashinfo->bhash_size);
111 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
112 struct inet_bind_bucket *tb;
113
114 spin_lock(&head->lock);
115 tb = inet_csk(sk)->icsk_bind_hash;
116 __sk_del_bind_node(sk);
117 inet_csk(sk)->icsk_bind_hash = NULL;
118 inet_sk(sk)->inet_num = 0;
119 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
120 spin_unlock(&head->lock);
121}
122
123void inet_put_port(struct sock *sk)
124{
125 local_bh_disable();
126 __inet_put_port(sk);
127 local_bh_enable();
128}
129EXPORT_SYMBOL(inet_put_port);
130
131int __inet_inherit_port(const struct sock *sk, struct sock *child)
132{
133 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
134 unsigned short port = inet_sk(child)->inet_num;
135 const int bhash = inet_bhashfn(sock_net(sk), port,
136 table->bhash_size);
137 struct inet_bind_hashbucket *head = &table->bhash[bhash];
138 struct inet_bind_bucket *tb;
139 int l3mdev;
140
141 spin_lock(&head->lock);
142 tb = inet_csk(sk)->icsk_bind_hash;
143 if (unlikely(!tb)) {
144 spin_unlock(&head->lock);
145 return -ENOENT;
146 }
147 if (tb->port != port) {
148 l3mdev = inet_sk_bound_l3mdev(sk);
149
150 /* NOTE: using tproxy and redirecting skbs to a proxy
151 * on a different listener port breaks the assumption
152 * that the listener socket's icsk_bind_hash is the same
153 * as that of the child socket. We have to look up or
154 * create a new bind bucket for the child here. */
155 inet_bind_bucket_for_each(tb, &head->chain) {
156 if (net_eq(ib_net(tb), sock_net(sk)) &&
157 tb->l3mdev == l3mdev && tb->port == port)
158 break;
159 }
160 if (!tb) {
161 tb = inet_bind_bucket_create(table->bind_bucket_cachep,
162 sock_net(sk), head, port,
163 l3mdev);
164 if (!tb) {
165 spin_unlock(&head->lock);
166 return -ENOMEM;
167 }
168 }
169 inet_csk_update_fastreuse(tb, child);
170 }
171 inet_bind_hash(child, tb, port);
172 spin_unlock(&head->lock);
173
174 return 0;
175}
176EXPORT_SYMBOL_GPL(__inet_inherit_port);
177
178static struct inet_listen_hashbucket *
179inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk)
180{
181 u32 hash;
182
183#if IS_ENABLED(CONFIG_IPV6)
184 if (sk->sk_family == AF_INET6)
185 hash = ipv6_portaddr_hash(sock_net(sk),
186 &sk->sk_v6_rcv_saddr,
187 inet_sk(sk)->inet_num);
188 else
189#endif
190 hash = ipv4_portaddr_hash(sock_net(sk),
191 inet_sk(sk)->inet_rcv_saddr,
192 inet_sk(sk)->inet_num);
193 return inet_lhash2_bucket(h, hash);
194}
195
196static void inet_hash2(struct inet_hashinfo *h, struct sock *sk)
197{
198 struct inet_listen_hashbucket *ilb2;
199
200 if (!h->lhash2)
201 return;
202
203 ilb2 = inet_lhash2_bucket_sk(h, sk);
204
205 spin_lock(&ilb2->lock);
206 if (sk->sk_reuseport && sk->sk_family == AF_INET6)
207 hlist_add_tail_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
208 &ilb2->head);
209 else
210 hlist_add_head_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
211 &ilb2->head);
212 ilb2->count++;
213 spin_unlock(&ilb2->lock);
214}
215
216static void inet_unhash2(struct inet_hashinfo *h, struct sock *sk)
217{
218 struct inet_listen_hashbucket *ilb2;
219
220 if (!h->lhash2 ||
221 WARN_ON_ONCE(hlist_unhashed(&inet_csk(sk)->icsk_listen_portaddr_node)))
222 return;
223
224 ilb2 = inet_lhash2_bucket_sk(h, sk);
225
226 spin_lock(&ilb2->lock);
227 hlist_del_init_rcu(&inet_csk(sk)->icsk_listen_portaddr_node);
228 ilb2->count--;
229 spin_unlock(&ilb2->lock);
230}
231
232static inline int compute_score(struct sock *sk, struct net *net,
233 const unsigned short hnum, const __be32 daddr,
234 const int dif, const int sdif)
235{
236 int score = -1;
237
238 if (net_eq(sock_net(sk), net) && sk->sk_num == hnum &&
239 !ipv6_only_sock(sk)) {
240 if (sk->sk_rcv_saddr != daddr)
241 return -1;
242
243 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
244 return -1;
245 score = sk->sk_bound_dev_if ? 2 : 1;
246
247 if (sk->sk_family == PF_INET)
248 score++;
249 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
250 score++;
251 }
252 return score;
253}
254
255static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
256 struct sk_buff *skb, int doff,
257 __be32 saddr, __be16 sport,
258 __be32 daddr, unsigned short hnum)
259{
260 struct sock *reuse_sk = NULL;
261 u32 phash;
262
263 if (sk->sk_reuseport) {
264 phash = inet_ehashfn(net, daddr, hnum, saddr, sport);
265 reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
266 }
267 return reuse_sk;
268}
269
270/*
271 * Here are some nice properties to exploit here. The BSD API
272 * does not allow a listening sock to specify the remote port nor the
273 * remote address for the connection. So always assume those are both
274 * wildcarded during the search since they can never be otherwise.
275 */
276
277/* called with rcu_read_lock() : No refcount taken on the socket */
278static struct sock *inet_lhash2_lookup(struct net *net,
279 struct inet_listen_hashbucket *ilb2,
280 struct sk_buff *skb, int doff,
281 const __be32 saddr, __be16 sport,
282 const __be32 daddr, const unsigned short hnum,
283 const int dif, const int sdif)
284{
285 struct inet_connection_sock *icsk;
286 struct sock *sk, *result = NULL;
287 int score, hiscore = 0;
288
289 inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
290 sk = (struct sock *)icsk;
291 score = compute_score(sk, net, hnum, daddr, dif, sdif);
292 if (score > hiscore) {
293 result = lookup_reuseport(net, sk, skb, doff,
294 saddr, sport, daddr, hnum);
295 if (result)
296 return result;
297
298 result = sk;
299 hiscore = score;
300 }
301 }
302
303 return result;
304}
305
306static inline struct sock *inet_lookup_run_bpf(struct net *net,
307 struct inet_hashinfo *hashinfo,
308 struct sk_buff *skb, int doff,
309 __be32 saddr, __be16 sport,
310 __be32 daddr, u16 hnum)
311{
312 struct sock *sk, *reuse_sk;
313 bool no_reuseport;
314
315 if (hashinfo != &tcp_hashinfo)
316 return NULL; /* only TCP is supported */
317
318 no_reuseport = bpf_sk_lookup_run_v4(net, IPPROTO_TCP,
319 saddr, sport, daddr, hnum, &sk);
320 if (no_reuseport || IS_ERR_OR_NULL(sk))
321 return sk;
322
323 reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
324 if (reuse_sk)
325 sk = reuse_sk;
326 return sk;
327}
328
329struct sock *__inet_lookup_listener(struct net *net,
330 struct inet_hashinfo *hashinfo,
331 struct sk_buff *skb, int doff,
332 const __be32 saddr, __be16 sport,
333 const __be32 daddr, const unsigned short hnum,
334 const int dif, const int sdif)
335{
336 struct inet_listen_hashbucket *ilb2;
337 struct sock *result = NULL;
338 unsigned int hash2;
339
340 /* Lookup redirect from BPF */
341 if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
342 result = inet_lookup_run_bpf(net, hashinfo, skb, doff,
343 saddr, sport, daddr, hnum);
344 if (result)
345 goto done;
346 }
347
348 hash2 = ipv4_portaddr_hash(net, daddr, hnum);
349 ilb2 = inet_lhash2_bucket(hashinfo, hash2);
350
351 result = inet_lhash2_lookup(net, ilb2, skb, doff,
352 saddr, sport, daddr, hnum,
353 dif, sdif);
354 if (result)
355 goto done;
356
357 /* Lookup lhash2 with INADDR_ANY */
358 hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
359 ilb2 = inet_lhash2_bucket(hashinfo, hash2);
360
361 result = inet_lhash2_lookup(net, ilb2, skb, doff,
362 saddr, sport, htonl(INADDR_ANY), hnum,
363 dif, sdif);
364done:
365 if (IS_ERR(result))
366 return NULL;
367 return result;
368}
369EXPORT_SYMBOL_GPL(__inet_lookup_listener);
370
371/* All sockets share common refcount, but have different destructors */
372void sock_gen_put(struct sock *sk)
373{
374 if (!refcount_dec_and_test(&sk->sk_refcnt))
375 return;
376
377 if (sk->sk_state == TCP_TIME_WAIT)
378 inet_twsk_free(inet_twsk(sk));
379 else if (sk->sk_state == TCP_NEW_SYN_RECV)
380 reqsk_free(inet_reqsk(sk));
381 else
382 sk_free(sk);
383}
384EXPORT_SYMBOL_GPL(sock_gen_put);
385
386void sock_edemux(struct sk_buff *skb)
387{
388 sock_gen_put(skb->sk);
389}
390EXPORT_SYMBOL(sock_edemux);
391
392struct sock *__inet_lookup_established(struct net *net,
393 struct inet_hashinfo *hashinfo,
394 const __be32 saddr, const __be16 sport,
395 const __be32 daddr, const u16 hnum,
396 const int dif, const int sdif)
397{
398 INET_ADDR_COOKIE(acookie, saddr, daddr);
399 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
400 struct sock *sk;
401 const struct hlist_nulls_node *node;
402 /* Optimize here for direct hit, only listening connections can
403 * have wildcards anyways.
404 */
405 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
406 unsigned int slot = hash & hashinfo->ehash_mask;
407 struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
408
409begin:
410 sk_nulls_for_each_rcu(sk, node, &head->chain) {
411 if (sk->sk_hash != hash)
412 continue;
413 if (likely(INET_MATCH(sk, net, acookie,
414 saddr, daddr, ports, dif, sdif))) {
415 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
416 goto out;
417 if (unlikely(!INET_MATCH(sk, net, acookie,
418 saddr, daddr, ports,
419 dif, sdif))) {
420 sock_gen_put(sk);
421 goto begin;
422 }
423 goto found;
424 }
425 }
426 /*
427 * if the nulls value we got at the end of this lookup is
428 * not the expected one, we must restart lookup.
429 * We probably met an item that was moved to another chain.
430 */
431 if (get_nulls_value(node) != slot)
432 goto begin;
433out:
434 sk = NULL;
435found:
436 return sk;
437}
438EXPORT_SYMBOL_GPL(__inet_lookup_established);
439
440/* called with local bh disabled */
441static int __inet_check_established(struct inet_timewait_death_row *death_row,
442 struct sock *sk, __u16 lport,
443 struct inet_timewait_sock **twp)
444{
445 struct inet_hashinfo *hinfo = death_row->hashinfo;
446 struct inet_sock *inet = inet_sk(sk);
447 __be32 daddr = inet->inet_rcv_saddr;
448 __be32 saddr = inet->inet_daddr;
449 int dif = sk->sk_bound_dev_if;
450 struct net *net = sock_net(sk);
451 int sdif = l3mdev_master_ifindex_by_index(net, dif);
452 INET_ADDR_COOKIE(acookie, saddr, daddr);
453 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
454 unsigned int hash = inet_ehashfn(net, daddr, lport,
455 saddr, inet->inet_dport);
456 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
457 spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
458 struct sock *sk2;
459 const struct hlist_nulls_node *node;
460 struct inet_timewait_sock *tw = NULL;
461
462 spin_lock(lock);
463
464 sk_nulls_for_each(sk2, node, &head->chain) {
465 if (sk2->sk_hash != hash)
466 continue;
467
468 if (likely(INET_MATCH(sk2, net, acookie,
469 saddr, daddr, ports, dif, sdif))) {
470 if (sk2->sk_state == TCP_TIME_WAIT) {
471 tw = inet_twsk(sk2);
472 if (twsk_unique(sk, sk2, twp))
473 break;
474 }
475 goto not_unique;
476 }
477 }
478
479 /* Must record num and sport now. Otherwise we will see
480 * in hash table socket with a funny identity.
481 */
482 inet->inet_num = lport;
483 inet->inet_sport = htons(lport);
484 sk->sk_hash = hash;
485 WARN_ON(!sk_unhashed(sk));
486 __sk_nulls_add_node_rcu(sk, &head->chain);
487 if (tw) {
488 sk_nulls_del_node_init_rcu((struct sock *)tw);
489 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
490 }
491 spin_unlock(lock);
492 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
493
494 if (twp) {
495 *twp = tw;
496 } else if (tw) {
497 /* Silly. Should hash-dance instead... */
498 inet_twsk_deschedule_put(tw);
499 }
500 return 0;
501
502not_unique:
503 spin_unlock(lock);
504 return -EADDRNOTAVAIL;
505}
506
507static u32 inet_sk_port_offset(const struct sock *sk)
508{
509 const struct inet_sock *inet = inet_sk(sk);
510
511 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
512 inet->inet_daddr,
513 inet->inet_dport);
514}
515
516/* Searches for an exsiting socket in the ehash bucket list.
517 * Returns true if found, false otherwise.
518 */
519static bool inet_ehash_lookup_by_sk(struct sock *sk,
520 struct hlist_nulls_head *list)
521{
522 const __portpair ports = INET_COMBINED_PORTS(sk->sk_dport, sk->sk_num);
523 const int sdif = sk->sk_bound_dev_if;
524 const int dif = sk->sk_bound_dev_if;
525 const struct hlist_nulls_node *node;
526 struct net *net = sock_net(sk);
527 struct sock *esk;
528
529 INET_ADDR_COOKIE(acookie, sk->sk_daddr, sk->sk_rcv_saddr);
530
531 sk_nulls_for_each_rcu(esk, node, list) {
532 if (esk->sk_hash != sk->sk_hash)
533 continue;
534 if (sk->sk_family == AF_INET) {
535 if (unlikely(INET_MATCH(esk, net, acookie,
536 sk->sk_daddr,
537 sk->sk_rcv_saddr,
538 ports, dif, sdif))) {
539 return true;
540 }
541 }
542#if IS_ENABLED(CONFIG_IPV6)
543 else if (sk->sk_family == AF_INET6) {
544 if (unlikely(INET6_MATCH(esk, net,
545 &sk->sk_v6_daddr,
546 &sk->sk_v6_rcv_saddr,
547 ports, dif, sdif))) {
548 return true;
549 }
550 }
551#endif
552 }
553 return false;
554}
555
556/* Insert a socket into ehash, and eventually remove another one
557 * (The another one can be a SYN_RECV or TIMEWAIT)
558 * If an existing socket already exists, socket sk is not inserted,
559 * and sets found_dup_sk parameter to true.
560 */
561bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk)
562{
563 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
564 struct hlist_nulls_head *list;
565 struct inet_ehash_bucket *head;
566 spinlock_t *lock;
567 bool ret = true;
568
569 WARN_ON_ONCE(!sk_unhashed(sk));
570
571 sk->sk_hash = sk_ehashfn(sk);
572 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
573 list = &head->chain;
574 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
575
576 spin_lock(lock);
577 if (osk) {
578 WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
579 ret = sk_nulls_del_node_init_rcu(osk);
580 } else if (found_dup_sk) {
581 *found_dup_sk = inet_ehash_lookup_by_sk(sk, list);
582 if (*found_dup_sk)
583 ret = false;
584 }
585
586 if (ret)
587 __sk_nulls_add_node_rcu(sk, list);
588
589 spin_unlock(lock);
590
591 return ret;
592}
593
594bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, bool *found_dup_sk)
595{
596 bool ok = inet_ehash_insert(sk, osk, found_dup_sk);
597
598 if (ok) {
599 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
600 } else {
601 percpu_counter_inc(sk->sk_prot->orphan_count);
602 inet_sk_set_state(sk, TCP_CLOSE);
603 sock_set_flag(sk, SOCK_DEAD);
604 inet_csk_destroy_sock(sk);
605 }
606 return ok;
607}
608EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
609
610static int inet_reuseport_add_sock(struct sock *sk,
611 struct inet_listen_hashbucket *ilb)
612{
613 struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
614 const struct hlist_nulls_node *node;
615 struct sock *sk2;
616 kuid_t uid = sock_i_uid(sk);
617
618 sk_nulls_for_each_rcu(sk2, node, &ilb->nulls_head) {
619 if (sk2 != sk &&
620 sk2->sk_family == sk->sk_family &&
621 ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
622 sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
623 inet_csk(sk2)->icsk_bind_hash == tb &&
624 sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
625 inet_rcv_saddr_equal(sk, sk2, false))
626 return reuseport_add_sock(sk, sk2,
627 inet_rcv_saddr_any(sk));
628 }
629
630 return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
631}
632
633int __inet_hash(struct sock *sk, struct sock *osk)
634{
635 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
636 struct inet_listen_hashbucket *ilb;
637 int err = 0;
638
639 if (sk->sk_state != TCP_LISTEN) {
640 inet_ehash_nolisten(sk, osk, NULL);
641 return 0;
642 }
643 WARN_ON(!sk_unhashed(sk));
644 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
645
646 spin_lock(&ilb->lock);
647 if (sk->sk_reuseport) {
648 err = inet_reuseport_add_sock(sk, ilb);
649 if (err)
650 goto unlock;
651 }
652 if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
653 sk->sk_family == AF_INET6)
654 __sk_nulls_add_node_tail_rcu(sk, &ilb->nulls_head);
655 else
656 __sk_nulls_add_node_rcu(sk, &ilb->nulls_head);
657 inet_hash2(hashinfo, sk);
658 ilb->count++;
659 sock_set_flag(sk, SOCK_RCU_FREE);
660 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
661unlock:
662 spin_unlock(&ilb->lock);
663
664 return err;
665}
666EXPORT_SYMBOL(__inet_hash);
667
668int inet_hash(struct sock *sk)
669{
670 int err = 0;
671
672 if (sk->sk_state != TCP_CLOSE) {
673 local_bh_disable();
674 err = __inet_hash(sk, NULL);
675 local_bh_enable();
676 }
677
678 return err;
679}
680EXPORT_SYMBOL_GPL(inet_hash);
681
682void inet_unhash(struct sock *sk)
683{
684 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
685 struct inet_listen_hashbucket *ilb = NULL;
686 spinlock_t *lock;
687
688 if (sk_unhashed(sk))
689 return;
690
691 if (sk->sk_state == TCP_LISTEN) {
692 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
693 lock = &ilb->lock;
694 } else {
695 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
696 }
697 spin_lock_bh(lock);
698 if (sk_unhashed(sk))
699 goto unlock;
700
701 if (rcu_access_pointer(sk->sk_reuseport_cb))
702 reuseport_stop_listen_sock(sk);
703 if (ilb) {
704 inet_unhash2(hashinfo, sk);
705 ilb->count--;
706 }
707 __sk_nulls_del_node_init_rcu(sk);
708 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
709unlock:
710 spin_unlock_bh(lock);
711}
712EXPORT_SYMBOL_GPL(inet_unhash);
713
714/* RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm
715 * Note that we use 32bit integers (vs RFC 'short integers')
716 * because 2^16 is not a multiple of num_ephemeral and this
717 * property might be used by clever attacker.
718 * RFC claims using TABLE_LENGTH=10 buckets gives an improvement,
719 * we use 256 instead to really give more isolation and
720 * privacy, this only consumes 1 KB of kernel memory.
721 */
722#define INET_TABLE_PERTURB_SHIFT 8
723static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT];
724
725int __inet_hash_connect(struct inet_timewait_death_row *death_row,
726 struct sock *sk, u32 port_offset,
727 int (*check_established)(struct inet_timewait_death_row *,
728 struct sock *, __u16, struct inet_timewait_sock **))
729{
730 struct inet_hashinfo *hinfo = death_row->hashinfo;
731 struct inet_timewait_sock *tw = NULL;
732 struct inet_bind_hashbucket *head;
733 int port = inet_sk(sk)->inet_num;
734 struct net *net = sock_net(sk);
735 struct inet_bind_bucket *tb;
736 u32 remaining, offset;
737 int ret, i, low, high;
738 int l3mdev;
739 u32 index;
740
741 if (port) {
742 head = &hinfo->bhash[inet_bhashfn(net, port,
743 hinfo->bhash_size)];
744 tb = inet_csk(sk)->icsk_bind_hash;
745 spin_lock_bh(&head->lock);
746 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
747 inet_ehash_nolisten(sk, NULL, NULL);
748 spin_unlock_bh(&head->lock);
749 return 0;
750 }
751 spin_unlock(&head->lock);
752 /* No definite answer... Walk to established hash table */
753 ret = check_established(death_row, sk, port, NULL);
754 local_bh_enable();
755 return ret;
756 }
757
758 l3mdev = inet_sk_bound_l3mdev(sk);
759
760 inet_get_local_port_range(net, &low, &high);
761 high++; /* [32768, 60999] -> [32768, 61000[ */
762 remaining = high - low;
763 if (likely(remaining > 1))
764 remaining &= ~1U;
765
766 net_get_random_once(table_perturb, sizeof(table_perturb));
767 index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT);
768
769 offset = (READ_ONCE(table_perturb[index]) + port_offset) % remaining;
770 /* In first pass we try ports of @low parity.
771 * inet_csk_get_port() does the opposite choice.
772 */
773 offset &= ~1U;
774other_parity_scan:
775 port = low + offset;
776 for (i = 0; i < remaining; i += 2, port += 2) {
777 if (unlikely(port >= high))
778 port -= remaining;
779 if (inet_is_local_reserved_port(net, port))
780 continue;
781 head = &hinfo->bhash[inet_bhashfn(net, port,
782 hinfo->bhash_size)];
783 spin_lock_bh(&head->lock);
784
785 /* Does not bother with rcv_saddr checks, because
786 * the established check is already unique enough.
787 */
788 inet_bind_bucket_for_each(tb, &head->chain) {
789 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
790 tb->port == port) {
791 if (tb->fastreuse >= 0 ||
792 tb->fastreuseport >= 0)
793 goto next_port;
794 WARN_ON(hlist_empty(&tb->owners));
795 if (!check_established(death_row, sk,
796 port, &tw))
797 goto ok;
798 goto next_port;
799 }
800 }
801
802 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
803 net, head, port, l3mdev);
804 if (!tb) {
805 spin_unlock_bh(&head->lock);
806 return -ENOMEM;
807 }
808 tb->fastreuse = -1;
809 tb->fastreuseport = -1;
810 goto ok;
811next_port:
812 spin_unlock_bh(&head->lock);
813 cond_resched();
814 }
815
816 offset++;
817 if ((offset & 1) && remaining > 1)
818 goto other_parity_scan;
819
820 return -EADDRNOTAVAIL;
821
822ok:
823 /* If our first attempt found a candidate, skip next candidate
824 * in 1/16 of cases to add some noise.
825 */
826 if (!i && !(prandom_u32() % 16))
827 i = 2;
828 WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2);
829
830 /* Head lock still held and bh's disabled */
831 inet_bind_hash(sk, tb, port);
832 if (sk_unhashed(sk)) {
833 inet_sk(sk)->inet_sport = htons(port);
834 inet_ehash_nolisten(sk, (struct sock *)tw, NULL);
835 }
836 if (tw)
837 inet_twsk_bind_unhash(tw, hinfo);
838 spin_unlock(&head->lock);
839 if (tw)
840 inet_twsk_deschedule_put(tw);
841 local_bh_enable();
842 return 0;
843}
844
845/*
846 * Bind a port for a connect operation and hash it.
847 */
848int inet_hash_connect(struct inet_timewait_death_row *death_row,
849 struct sock *sk)
850{
851 u32 port_offset = 0;
852
853 if (!inet_sk(sk)->inet_num)
854 port_offset = inet_sk_port_offset(sk);
855 return __inet_hash_connect(death_row, sk, port_offset,
856 __inet_check_established);
857}
858EXPORT_SYMBOL_GPL(inet_hash_connect);
859
860void inet_hashinfo_init(struct inet_hashinfo *h)
861{
862 int i;
863
864 for (i = 0; i < INET_LHTABLE_SIZE; i++) {
865 spin_lock_init(&h->listening_hash[i].lock);
866 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].nulls_head,
867 i + LISTENING_NULLS_BASE);
868 h->listening_hash[i].count = 0;
869 }
870
871 h->lhash2 = NULL;
872}
873EXPORT_SYMBOL_GPL(inet_hashinfo_init);
874
875static void init_hashinfo_lhash2(struct inet_hashinfo *h)
876{
877 int i;
878
879 for (i = 0; i <= h->lhash2_mask; i++) {
880 spin_lock_init(&h->lhash2[i].lock);
881 INIT_HLIST_HEAD(&h->lhash2[i].head);
882 h->lhash2[i].count = 0;
883 }
884}
885
886void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
887 unsigned long numentries, int scale,
888 unsigned long low_limit,
889 unsigned long high_limit)
890{
891 h->lhash2 = alloc_large_system_hash(name,
892 sizeof(*h->lhash2),
893 numentries,
894 scale,
895 0,
896 NULL,
897 &h->lhash2_mask,
898 low_limit,
899 high_limit);
900 init_hashinfo_lhash2(h);
901}
902
903int inet_hashinfo2_init_mod(struct inet_hashinfo *h)
904{
905 h->lhash2 = kmalloc_array(INET_LHTABLE_SIZE, sizeof(*h->lhash2), GFP_KERNEL);
906 if (!h->lhash2)
907 return -ENOMEM;
908
909 h->lhash2_mask = INET_LHTABLE_SIZE - 1;
910 /* INET_LHTABLE_SIZE must be a power of 2 */
911 BUG_ON(INET_LHTABLE_SIZE & h->lhash2_mask);
912
913 init_hashinfo_lhash2(h);
914 return 0;
915}
916EXPORT_SYMBOL_GPL(inet_hashinfo2_init_mod);
917
918int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
919{
920 unsigned int locksz = sizeof(spinlock_t);
921 unsigned int i, nblocks = 1;
922
923 if (locksz != 0) {
924 /* allocate 2 cache lines or at least one spinlock per cpu */
925 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
926 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
927
928 /* no more locks than number of hash buckets */
929 nblocks = min(nblocks, hashinfo->ehash_mask + 1);
930
931 hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
932 if (!hashinfo->ehash_locks)
933 return -ENOMEM;
934
935 for (i = 0; i < nblocks; i++)
936 spin_lock_init(&hashinfo->ehash_locks[i]);
937 }
938 hashinfo->ehash_locks_mask = nblocks - 1;
939 return 0;
940}
941EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Generic INET transport hashtables
7 *
8 * Authors: Lotsa people, from code originally in tcp
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16#include <linux/module.h>
17#include <linux/random.h>
18#include <linux/sched.h>
19#include <linux/slab.h>
20#include <linux/wait.h>
21#include <linux/vmalloc.h>
22#include <linux/bootmem.h>
23
24#include <net/addrconf.h>
25#include <net/inet_connection_sock.h>
26#include <net/inet_hashtables.h>
27#include <net/secure_seq.h>
28#include <net/ip.h>
29#include <net/tcp.h>
30#include <net/sock_reuseport.h>
31
32static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
33 const __u16 lport, const __be32 faddr,
34 const __be16 fport)
35{
36 static u32 inet_ehash_secret __read_mostly;
37
38 net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
39
40 return __inet_ehashfn(laddr, lport, faddr, fport,
41 inet_ehash_secret + net_hash_mix(net));
42}
43
44/* This function handles inet_sock, but also timewait and request sockets
45 * for IPv4/IPv6.
46 */
47static u32 sk_ehashfn(const struct sock *sk)
48{
49#if IS_ENABLED(CONFIG_IPV6)
50 if (sk->sk_family == AF_INET6 &&
51 !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
52 return inet6_ehashfn(sock_net(sk),
53 &sk->sk_v6_rcv_saddr, sk->sk_num,
54 &sk->sk_v6_daddr, sk->sk_dport);
55#endif
56 return inet_ehashfn(sock_net(sk),
57 sk->sk_rcv_saddr, sk->sk_num,
58 sk->sk_daddr, sk->sk_dport);
59}
60
61/*
62 * Allocate and initialize a new local port bind bucket.
63 * The bindhash mutex for snum's hash chain must be held here.
64 */
65struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
66 struct net *net,
67 struct inet_bind_hashbucket *head,
68 const unsigned short snum)
69{
70 struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
71
72 if (tb) {
73 write_pnet(&tb->ib_net, net);
74 tb->port = snum;
75 tb->fastreuse = 0;
76 tb->fastreuseport = 0;
77 INIT_HLIST_HEAD(&tb->owners);
78 hlist_add_head(&tb->node, &head->chain);
79 }
80 return tb;
81}
82
83/*
84 * Caller must hold hashbucket lock for this tb with local BH disabled
85 */
86void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
87{
88 if (hlist_empty(&tb->owners)) {
89 __hlist_del(&tb->node);
90 kmem_cache_free(cachep, tb);
91 }
92}
93
94void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
95 const unsigned short snum)
96{
97 inet_sk(sk)->inet_num = snum;
98 sk_add_bind_node(sk, &tb->owners);
99 inet_csk(sk)->icsk_bind_hash = tb;
100}
101
102/*
103 * Get rid of any references to a local port held by the given sock.
104 */
105static void __inet_put_port(struct sock *sk)
106{
107 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
108 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
109 hashinfo->bhash_size);
110 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
111 struct inet_bind_bucket *tb;
112
113 spin_lock(&head->lock);
114 tb = inet_csk(sk)->icsk_bind_hash;
115 __sk_del_bind_node(sk);
116 inet_csk(sk)->icsk_bind_hash = NULL;
117 inet_sk(sk)->inet_num = 0;
118 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
119 spin_unlock(&head->lock);
120}
121
122void inet_put_port(struct sock *sk)
123{
124 local_bh_disable();
125 __inet_put_port(sk);
126 local_bh_enable();
127}
128EXPORT_SYMBOL(inet_put_port);
129
130int __inet_inherit_port(const struct sock *sk, struct sock *child)
131{
132 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
133 unsigned short port = inet_sk(child)->inet_num;
134 const int bhash = inet_bhashfn(sock_net(sk), port,
135 table->bhash_size);
136 struct inet_bind_hashbucket *head = &table->bhash[bhash];
137 struct inet_bind_bucket *tb;
138
139 spin_lock(&head->lock);
140 tb = inet_csk(sk)->icsk_bind_hash;
141 if (unlikely(!tb)) {
142 spin_unlock(&head->lock);
143 return -ENOENT;
144 }
145 if (tb->port != port) {
146 /* NOTE: using tproxy and redirecting skbs to a proxy
147 * on a different listener port breaks the assumption
148 * that the listener socket's icsk_bind_hash is the same
149 * as that of the child socket. We have to look up or
150 * create a new bind bucket for the child here. */
151 inet_bind_bucket_for_each(tb, &head->chain) {
152 if (net_eq(ib_net(tb), sock_net(sk)) &&
153 tb->port == port)
154 break;
155 }
156 if (!tb) {
157 tb = inet_bind_bucket_create(table->bind_bucket_cachep,
158 sock_net(sk), head, port);
159 if (!tb) {
160 spin_unlock(&head->lock);
161 return -ENOMEM;
162 }
163 }
164 }
165 inet_bind_hash(child, tb, port);
166 spin_unlock(&head->lock);
167
168 return 0;
169}
170EXPORT_SYMBOL_GPL(__inet_inherit_port);
171
172static struct inet_listen_hashbucket *
173inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk)
174{
175 u32 hash;
176
177#if IS_ENABLED(CONFIG_IPV6)
178 if (sk->sk_family == AF_INET6)
179 hash = ipv6_portaddr_hash(sock_net(sk),
180 &sk->sk_v6_rcv_saddr,
181 inet_sk(sk)->inet_num);
182 else
183#endif
184 hash = ipv4_portaddr_hash(sock_net(sk),
185 inet_sk(sk)->inet_rcv_saddr,
186 inet_sk(sk)->inet_num);
187 return inet_lhash2_bucket(h, hash);
188}
189
190static void inet_hash2(struct inet_hashinfo *h, struct sock *sk)
191{
192 struct inet_listen_hashbucket *ilb2;
193
194 if (!h->lhash2)
195 return;
196
197 ilb2 = inet_lhash2_bucket_sk(h, sk);
198
199 spin_lock(&ilb2->lock);
200 if (sk->sk_reuseport && sk->sk_family == AF_INET6)
201 hlist_add_tail_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
202 &ilb2->head);
203 else
204 hlist_add_head_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
205 &ilb2->head);
206 ilb2->count++;
207 spin_unlock(&ilb2->lock);
208}
209
210static void inet_unhash2(struct inet_hashinfo *h, struct sock *sk)
211{
212 struct inet_listen_hashbucket *ilb2;
213
214 if (!h->lhash2 ||
215 WARN_ON_ONCE(hlist_unhashed(&inet_csk(sk)->icsk_listen_portaddr_node)))
216 return;
217
218 ilb2 = inet_lhash2_bucket_sk(h, sk);
219
220 spin_lock(&ilb2->lock);
221 hlist_del_init_rcu(&inet_csk(sk)->icsk_listen_portaddr_node);
222 ilb2->count--;
223 spin_unlock(&ilb2->lock);
224}
225
226static inline int compute_score(struct sock *sk, struct net *net,
227 const unsigned short hnum, const __be32 daddr,
228 const int dif, const int sdif, bool exact_dif)
229{
230 int score = -1;
231 struct inet_sock *inet = inet_sk(sk);
232
233 if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
234 !ipv6_only_sock(sk)) {
235 __be32 rcv_saddr = inet->inet_rcv_saddr;
236 score = sk->sk_family == PF_INET ? 2 : 1;
237 if (rcv_saddr) {
238 if (rcv_saddr != daddr)
239 return -1;
240 score += 4;
241 }
242 if (sk->sk_bound_dev_if || exact_dif) {
243 bool dev_match = (sk->sk_bound_dev_if == dif ||
244 sk->sk_bound_dev_if == sdif);
245
246 if (exact_dif && !dev_match)
247 return -1;
248 if (sk->sk_bound_dev_if && dev_match)
249 score += 4;
250 }
251 if (sk->sk_incoming_cpu == raw_smp_processor_id())
252 score++;
253 }
254 return score;
255}
256
257/*
258 * Here are some nice properties to exploit here. The BSD API
259 * does not allow a listening sock to specify the remote port nor the
260 * remote address for the connection. So always assume those are both
261 * wildcarded during the search since they can never be otherwise.
262 */
263
264/* called with rcu_read_lock() : No refcount taken on the socket */
265static struct sock *inet_lhash2_lookup(struct net *net,
266 struct inet_listen_hashbucket *ilb2,
267 struct sk_buff *skb, int doff,
268 const __be32 saddr, __be16 sport,
269 const __be32 daddr, const unsigned short hnum,
270 const int dif, const int sdif)
271{
272 bool exact_dif = inet_exact_dif_match(net, skb);
273 struct inet_connection_sock *icsk;
274 struct sock *sk, *result = NULL;
275 int score, hiscore = 0;
276 u32 phash = 0;
277
278 inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
279 sk = (struct sock *)icsk;
280 score = compute_score(sk, net, hnum, daddr,
281 dif, sdif, exact_dif);
282 if (score > hiscore) {
283 if (sk->sk_reuseport) {
284 phash = inet_ehashfn(net, daddr, hnum,
285 saddr, sport);
286 result = reuseport_select_sock(sk, phash,
287 skb, doff);
288 if (result)
289 return result;
290 }
291 result = sk;
292 hiscore = score;
293 }
294 }
295
296 return result;
297}
298
299struct sock *__inet_lookup_listener(struct net *net,
300 struct inet_hashinfo *hashinfo,
301 struct sk_buff *skb, int doff,
302 const __be32 saddr, __be16 sport,
303 const __be32 daddr, const unsigned short hnum,
304 const int dif, const int sdif)
305{
306 unsigned int hash = inet_lhashfn(net, hnum);
307 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
308 bool exact_dif = inet_exact_dif_match(net, skb);
309 struct inet_listen_hashbucket *ilb2;
310 struct sock *sk, *result = NULL;
311 int score, hiscore = 0;
312 unsigned int hash2;
313 u32 phash = 0;
314
315 if (ilb->count <= 10 || !hashinfo->lhash2)
316 goto port_lookup;
317
318 /* Too many sk in the ilb bucket (which is hashed by port alone).
319 * Try lhash2 (which is hashed by port and addr) instead.
320 */
321
322 hash2 = ipv4_portaddr_hash(net, daddr, hnum);
323 ilb2 = inet_lhash2_bucket(hashinfo, hash2);
324 if (ilb2->count > ilb->count)
325 goto port_lookup;
326
327 result = inet_lhash2_lookup(net, ilb2, skb, doff,
328 saddr, sport, daddr, hnum,
329 dif, sdif);
330 if (result)
331 return result;
332
333 /* Lookup lhash2 with INADDR_ANY */
334
335 hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
336 ilb2 = inet_lhash2_bucket(hashinfo, hash2);
337 if (ilb2->count > ilb->count)
338 goto port_lookup;
339
340 return inet_lhash2_lookup(net, ilb2, skb, doff,
341 saddr, sport, daddr, hnum,
342 dif, sdif);
343
344port_lookup:
345 sk_for_each_rcu(sk, &ilb->head) {
346 score = compute_score(sk, net, hnum, daddr,
347 dif, sdif, exact_dif);
348 if (score > hiscore) {
349 if (sk->sk_reuseport) {
350 phash = inet_ehashfn(net, daddr, hnum,
351 saddr, sport);
352 result = reuseport_select_sock(sk, phash,
353 skb, doff);
354 if (result)
355 return result;
356 }
357 result = sk;
358 hiscore = score;
359 }
360 }
361 return result;
362}
363EXPORT_SYMBOL_GPL(__inet_lookup_listener);
364
365/* All sockets share common refcount, but have different destructors */
366void sock_gen_put(struct sock *sk)
367{
368 if (!refcount_dec_and_test(&sk->sk_refcnt))
369 return;
370
371 if (sk->sk_state == TCP_TIME_WAIT)
372 inet_twsk_free(inet_twsk(sk));
373 else if (sk->sk_state == TCP_NEW_SYN_RECV)
374 reqsk_free(inet_reqsk(sk));
375 else
376 sk_free(sk);
377}
378EXPORT_SYMBOL_GPL(sock_gen_put);
379
380void sock_edemux(struct sk_buff *skb)
381{
382 sock_gen_put(skb->sk);
383}
384EXPORT_SYMBOL(sock_edemux);
385
386struct sock *__inet_lookup_established(struct net *net,
387 struct inet_hashinfo *hashinfo,
388 const __be32 saddr, const __be16 sport,
389 const __be32 daddr, const u16 hnum,
390 const int dif, const int sdif)
391{
392 INET_ADDR_COOKIE(acookie, saddr, daddr);
393 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
394 struct sock *sk;
395 const struct hlist_nulls_node *node;
396 /* Optimize here for direct hit, only listening connections can
397 * have wildcards anyways.
398 */
399 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
400 unsigned int slot = hash & hashinfo->ehash_mask;
401 struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
402
403begin:
404 sk_nulls_for_each_rcu(sk, node, &head->chain) {
405 if (sk->sk_hash != hash)
406 continue;
407 if (likely(INET_MATCH(sk, net, acookie,
408 saddr, daddr, ports, dif, sdif))) {
409 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
410 goto out;
411 if (unlikely(!INET_MATCH(sk, net, acookie,
412 saddr, daddr, ports,
413 dif, sdif))) {
414 sock_gen_put(sk);
415 goto begin;
416 }
417 goto found;
418 }
419 }
420 /*
421 * if the nulls value we got at the end of this lookup is
422 * not the expected one, we must restart lookup.
423 * We probably met an item that was moved to another chain.
424 */
425 if (get_nulls_value(node) != slot)
426 goto begin;
427out:
428 sk = NULL;
429found:
430 return sk;
431}
432EXPORT_SYMBOL_GPL(__inet_lookup_established);
433
434/* called with local bh disabled */
435static int __inet_check_established(struct inet_timewait_death_row *death_row,
436 struct sock *sk, __u16 lport,
437 struct inet_timewait_sock **twp)
438{
439 struct inet_hashinfo *hinfo = death_row->hashinfo;
440 struct inet_sock *inet = inet_sk(sk);
441 __be32 daddr = inet->inet_rcv_saddr;
442 __be32 saddr = inet->inet_daddr;
443 int dif = sk->sk_bound_dev_if;
444 struct net *net = sock_net(sk);
445 int sdif = l3mdev_master_ifindex_by_index(net, dif);
446 INET_ADDR_COOKIE(acookie, saddr, daddr);
447 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
448 unsigned int hash = inet_ehashfn(net, daddr, lport,
449 saddr, inet->inet_dport);
450 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
451 spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
452 struct sock *sk2;
453 const struct hlist_nulls_node *node;
454 struct inet_timewait_sock *tw = NULL;
455
456 spin_lock(lock);
457
458 sk_nulls_for_each(sk2, node, &head->chain) {
459 if (sk2->sk_hash != hash)
460 continue;
461
462 if (likely(INET_MATCH(sk2, net, acookie,
463 saddr, daddr, ports, dif, sdif))) {
464 if (sk2->sk_state == TCP_TIME_WAIT) {
465 tw = inet_twsk(sk2);
466 if (twsk_unique(sk, sk2, twp))
467 break;
468 }
469 goto not_unique;
470 }
471 }
472
473 /* Must record num and sport now. Otherwise we will see
474 * in hash table socket with a funny identity.
475 */
476 inet->inet_num = lport;
477 inet->inet_sport = htons(lport);
478 sk->sk_hash = hash;
479 WARN_ON(!sk_unhashed(sk));
480 __sk_nulls_add_node_rcu(sk, &head->chain);
481 if (tw) {
482 sk_nulls_del_node_init_rcu((struct sock *)tw);
483 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
484 }
485 spin_unlock(lock);
486 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
487
488 if (twp) {
489 *twp = tw;
490 } else if (tw) {
491 /* Silly. Should hash-dance instead... */
492 inet_twsk_deschedule_put(tw);
493 }
494 return 0;
495
496not_unique:
497 spin_unlock(lock);
498 return -EADDRNOTAVAIL;
499}
500
501static u32 inet_sk_port_offset(const struct sock *sk)
502{
503 const struct inet_sock *inet = inet_sk(sk);
504
505 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
506 inet->inet_daddr,
507 inet->inet_dport);
508}
509
510/* insert a socket into ehash, and eventually remove another one
511 * (The another one can be a SYN_RECV or TIMEWAIT
512 */
513bool inet_ehash_insert(struct sock *sk, struct sock *osk)
514{
515 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
516 struct hlist_nulls_head *list;
517 struct inet_ehash_bucket *head;
518 spinlock_t *lock;
519 bool ret = true;
520
521 WARN_ON_ONCE(!sk_unhashed(sk));
522
523 sk->sk_hash = sk_ehashfn(sk);
524 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
525 list = &head->chain;
526 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
527
528 spin_lock(lock);
529 if (osk) {
530 WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
531 ret = sk_nulls_del_node_init_rcu(osk);
532 }
533 if (ret)
534 __sk_nulls_add_node_rcu(sk, list);
535 spin_unlock(lock);
536 return ret;
537}
538
539bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
540{
541 bool ok = inet_ehash_insert(sk, osk);
542
543 if (ok) {
544 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
545 } else {
546 percpu_counter_inc(sk->sk_prot->orphan_count);
547 inet_sk_set_state(sk, TCP_CLOSE);
548 sock_set_flag(sk, SOCK_DEAD);
549 inet_csk_destroy_sock(sk);
550 }
551 return ok;
552}
553EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
554
555static int inet_reuseport_add_sock(struct sock *sk,
556 struct inet_listen_hashbucket *ilb)
557{
558 struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
559 struct sock *sk2;
560 kuid_t uid = sock_i_uid(sk);
561
562 sk_for_each_rcu(sk2, &ilb->head) {
563 if (sk2 != sk &&
564 sk2->sk_family == sk->sk_family &&
565 ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
566 sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
567 inet_csk(sk2)->icsk_bind_hash == tb &&
568 sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
569 inet_rcv_saddr_equal(sk, sk2, false))
570 return reuseport_add_sock(sk, sk2);
571 }
572
573 return reuseport_alloc(sk);
574}
575
576int __inet_hash(struct sock *sk, struct sock *osk)
577{
578 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
579 struct inet_listen_hashbucket *ilb;
580 int err = 0;
581
582 if (sk->sk_state != TCP_LISTEN) {
583 inet_ehash_nolisten(sk, osk);
584 return 0;
585 }
586 WARN_ON(!sk_unhashed(sk));
587 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
588
589 spin_lock(&ilb->lock);
590 if (sk->sk_reuseport) {
591 err = inet_reuseport_add_sock(sk, ilb);
592 if (err)
593 goto unlock;
594 }
595 if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
596 sk->sk_family == AF_INET6)
597 hlist_add_tail_rcu(&sk->sk_node, &ilb->head);
598 else
599 hlist_add_head_rcu(&sk->sk_node, &ilb->head);
600 inet_hash2(hashinfo, sk);
601 ilb->count++;
602 sock_set_flag(sk, SOCK_RCU_FREE);
603 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
604unlock:
605 spin_unlock(&ilb->lock);
606
607 return err;
608}
609EXPORT_SYMBOL(__inet_hash);
610
611int inet_hash(struct sock *sk)
612{
613 int err = 0;
614
615 if (sk->sk_state != TCP_CLOSE) {
616 local_bh_disable();
617 err = __inet_hash(sk, NULL);
618 local_bh_enable();
619 }
620
621 return err;
622}
623EXPORT_SYMBOL_GPL(inet_hash);
624
625void inet_unhash(struct sock *sk)
626{
627 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
628 struct inet_listen_hashbucket *ilb = NULL;
629 spinlock_t *lock;
630
631 if (sk_unhashed(sk))
632 return;
633
634 if (sk->sk_state == TCP_LISTEN) {
635 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
636 lock = &ilb->lock;
637 } else {
638 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
639 }
640 spin_lock_bh(lock);
641 if (sk_unhashed(sk))
642 goto unlock;
643
644 if (rcu_access_pointer(sk->sk_reuseport_cb))
645 reuseport_detach_sock(sk);
646 if (ilb) {
647 inet_unhash2(hashinfo, sk);
648 __sk_del_node_init(sk);
649 ilb->count--;
650 } else {
651 __sk_nulls_del_node_init_rcu(sk);
652 }
653 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
654unlock:
655 spin_unlock_bh(lock);
656}
657EXPORT_SYMBOL_GPL(inet_unhash);
658
659int __inet_hash_connect(struct inet_timewait_death_row *death_row,
660 struct sock *sk, u32 port_offset,
661 int (*check_established)(struct inet_timewait_death_row *,
662 struct sock *, __u16, struct inet_timewait_sock **))
663{
664 struct inet_hashinfo *hinfo = death_row->hashinfo;
665 struct inet_timewait_sock *tw = NULL;
666 struct inet_bind_hashbucket *head;
667 int port = inet_sk(sk)->inet_num;
668 struct net *net = sock_net(sk);
669 struct inet_bind_bucket *tb;
670 u32 remaining, offset;
671 int ret, i, low, high;
672 static u32 hint;
673
674 if (port) {
675 head = &hinfo->bhash[inet_bhashfn(net, port,
676 hinfo->bhash_size)];
677 tb = inet_csk(sk)->icsk_bind_hash;
678 spin_lock_bh(&head->lock);
679 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
680 inet_ehash_nolisten(sk, NULL);
681 spin_unlock_bh(&head->lock);
682 return 0;
683 }
684 spin_unlock(&head->lock);
685 /* No definite answer... Walk to established hash table */
686 ret = check_established(death_row, sk, port, NULL);
687 local_bh_enable();
688 return ret;
689 }
690
691 inet_get_local_port_range(net, &low, &high);
692 high++; /* [32768, 60999] -> [32768, 61000[ */
693 remaining = high - low;
694 if (likely(remaining > 1))
695 remaining &= ~1U;
696
697 offset = (hint + port_offset) % remaining;
698 /* In first pass we try ports of @low parity.
699 * inet_csk_get_port() does the opposite choice.
700 */
701 offset &= ~1U;
702other_parity_scan:
703 port = low + offset;
704 for (i = 0; i < remaining; i += 2, port += 2) {
705 if (unlikely(port >= high))
706 port -= remaining;
707 if (inet_is_local_reserved_port(net, port))
708 continue;
709 head = &hinfo->bhash[inet_bhashfn(net, port,
710 hinfo->bhash_size)];
711 spin_lock_bh(&head->lock);
712
713 /* Does not bother with rcv_saddr checks, because
714 * the established check is already unique enough.
715 */
716 inet_bind_bucket_for_each(tb, &head->chain) {
717 if (net_eq(ib_net(tb), net) && tb->port == port) {
718 if (tb->fastreuse >= 0 ||
719 tb->fastreuseport >= 0)
720 goto next_port;
721 WARN_ON(hlist_empty(&tb->owners));
722 if (!check_established(death_row, sk,
723 port, &tw))
724 goto ok;
725 goto next_port;
726 }
727 }
728
729 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
730 net, head, port);
731 if (!tb) {
732 spin_unlock_bh(&head->lock);
733 return -ENOMEM;
734 }
735 tb->fastreuse = -1;
736 tb->fastreuseport = -1;
737 goto ok;
738next_port:
739 spin_unlock_bh(&head->lock);
740 cond_resched();
741 }
742
743 offset++;
744 if ((offset & 1) && remaining > 1)
745 goto other_parity_scan;
746
747 return -EADDRNOTAVAIL;
748
749ok:
750 hint += i + 2;
751
752 /* Head lock still held and bh's disabled */
753 inet_bind_hash(sk, tb, port);
754 if (sk_unhashed(sk)) {
755 inet_sk(sk)->inet_sport = htons(port);
756 inet_ehash_nolisten(sk, (struct sock *)tw);
757 }
758 if (tw)
759 inet_twsk_bind_unhash(tw, hinfo);
760 spin_unlock(&head->lock);
761 if (tw)
762 inet_twsk_deschedule_put(tw);
763 local_bh_enable();
764 return 0;
765}
766
767/*
768 * Bind a port for a connect operation and hash it.
769 */
770int inet_hash_connect(struct inet_timewait_death_row *death_row,
771 struct sock *sk)
772{
773 u32 port_offset = 0;
774
775 if (!inet_sk(sk)->inet_num)
776 port_offset = inet_sk_port_offset(sk);
777 return __inet_hash_connect(death_row, sk, port_offset,
778 __inet_check_established);
779}
780EXPORT_SYMBOL_GPL(inet_hash_connect);
781
782void inet_hashinfo_init(struct inet_hashinfo *h)
783{
784 int i;
785
786 for (i = 0; i < INET_LHTABLE_SIZE; i++) {
787 spin_lock_init(&h->listening_hash[i].lock);
788 INIT_HLIST_HEAD(&h->listening_hash[i].head);
789 h->listening_hash[i].count = 0;
790 }
791
792 h->lhash2 = NULL;
793}
794EXPORT_SYMBOL_GPL(inet_hashinfo_init);
795
796void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
797 unsigned long numentries, int scale,
798 unsigned long low_limit,
799 unsigned long high_limit)
800{
801 unsigned int i;
802
803 h->lhash2 = alloc_large_system_hash(name,
804 sizeof(*h->lhash2),
805 numentries,
806 scale,
807 0,
808 NULL,
809 &h->lhash2_mask,
810 low_limit,
811 high_limit);
812
813 for (i = 0; i <= h->lhash2_mask; i++) {
814 spin_lock_init(&h->lhash2[i].lock);
815 INIT_HLIST_HEAD(&h->lhash2[i].head);
816 h->lhash2[i].count = 0;
817 }
818}
819
820int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
821{
822 unsigned int locksz = sizeof(spinlock_t);
823 unsigned int i, nblocks = 1;
824
825 if (locksz != 0) {
826 /* allocate 2 cache lines or at least one spinlock per cpu */
827 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
828 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
829
830 /* no more locks than number of hash buckets */
831 nblocks = min(nblocks, hashinfo->ehash_mask + 1);
832
833 hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
834 if (!hashinfo->ehash_locks)
835 return -ENOMEM;
836
837 for (i = 0; i < nblocks; i++)
838 spin_lock_init(&hashinfo->ehash_locks[i]);
839 }
840 hashinfo->ehash_locks_mask = nblocks - 1;
841 return 0;
842}
843EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);