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
 22#include <net/inet_connection_sock.h>
 23#include <net/inet_hashtables.h>
 24#include <net/secure_seq.h>
 25#include <net/ip.h>
 26
 27/*
 28 * Allocate and initialize a new local port bind bucket.
 29 * The bindhash mutex for snum's hash chain must be held here.
 30 */
 31struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
 32						 struct net *net,
 33						 struct inet_bind_hashbucket *head,
 34						 const unsigned short snum)
 35{
 36	struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
 37
 38	if (tb != NULL) {
 39		write_pnet(&tb->ib_net, hold_net(net));
 40		tb->port      = snum;
 41		tb->fastreuse = 0;
 42		tb->num_owners = 0;
 43		INIT_HLIST_HEAD(&tb->owners);
 44		hlist_add_head(&tb->node, &head->chain);
 45	}
 46	return tb;
 47}
 48
 49/*
 50 * Caller must hold hashbucket lock for this tb with local BH disabled
 51 */
 52void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
 53{
 54	if (hlist_empty(&tb->owners)) {
 55		__hlist_del(&tb->node);
 56		release_net(ib_net(tb));
 57		kmem_cache_free(cachep, tb);
 58	}
 59}
 60
 61void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
 62		    const unsigned short snum)
 63{
 64	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 65
 66	atomic_inc(&hashinfo->bsockets);
 67
 68	inet_sk(sk)->inet_num = snum;
 69	sk_add_bind_node(sk, &tb->owners);
 70	tb->num_owners++;
 71	inet_csk(sk)->icsk_bind_hash = tb;
 72}
 73
 74/*
 75 * Get rid of any references to a local port held by the given sock.
 76 */
 77static void __inet_put_port(struct sock *sk)
 78{
 79	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 80	const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
 81			hashinfo->bhash_size);
 82	struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
 83	struct inet_bind_bucket *tb;
 84
 85	atomic_dec(&hashinfo->bsockets);
 86
 87	spin_lock(&head->lock);
 88	tb = inet_csk(sk)->icsk_bind_hash;
 89	__sk_del_bind_node(sk);
 90	tb->num_owners--;
 91	inet_csk(sk)->icsk_bind_hash = NULL;
 92	inet_sk(sk)->inet_num = 0;
 93	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
 94	spin_unlock(&head->lock);
 95}
 96
 97void inet_put_port(struct sock *sk)
 98{
 99	local_bh_disable();
100	__inet_put_port(sk);
101	local_bh_enable();
102}
103EXPORT_SYMBOL(inet_put_port);
104
105int __inet_inherit_port(struct sock *sk, struct sock *child)
106{
107	struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
108	unsigned short port = inet_sk(child)->inet_num;
109	const int bhash = inet_bhashfn(sock_net(sk), port,
110			table->bhash_size);
111	struct inet_bind_hashbucket *head = &table->bhash[bhash];
112	struct inet_bind_bucket *tb;
113
114	spin_lock(&head->lock);
115	tb = inet_csk(sk)->icsk_bind_hash;
116	if (tb->port != port) {
117		/* NOTE: using tproxy and redirecting skbs to a proxy
118		 * on a different listener port breaks the assumption
119		 * that the listener socket's icsk_bind_hash is the same
120		 * as that of the child socket. We have to look up or
121		 * create a new bind bucket for the child here. */
122		struct hlist_node *node;
123		inet_bind_bucket_for_each(tb, node, &head->chain) {
124			if (net_eq(ib_net(tb), sock_net(sk)) &&
125			    tb->port == port)
126				break;
127		}
128		if (!node) {
129			tb = inet_bind_bucket_create(table->bind_bucket_cachep,
130						     sock_net(sk), head, port);
131			if (!tb) {
132				spin_unlock(&head->lock);
133				return -ENOMEM;
134			}
135		}
136	}
137	inet_bind_hash(child, tb, port);
138	spin_unlock(&head->lock);
139
140	return 0;
141}
142EXPORT_SYMBOL_GPL(__inet_inherit_port);
143
144static inline int compute_score(struct sock *sk, struct net *net,
145				const unsigned short hnum, const __be32 daddr,
146				const int dif)
147{
148	int score = -1;
149	struct inet_sock *inet = inet_sk(sk);
150
151	if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
152			!ipv6_only_sock(sk)) {
153		__be32 rcv_saddr = inet->inet_rcv_saddr;
154		score = sk->sk_family == PF_INET ? 1 : 0;
155		if (rcv_saddr) {
156			if (rcv_saddr != daddr)
157				return -1;
158			score += 2;
159		}
160		if (sk->sk_bound_dev_if) {
161			if (sk->sk_bound_dev_if != dif)
162				return -1;
163			score += 2;
164		}
165	}
166	return score;
167}
168
169/*
170 * Don't inline this cruft. Here are some nice properties to exploit here. The
171 * BSD API does not allow a listening sock to specify the remote port nor the
172 * remote address for the connection. So always assume those are both
173 * wildcarded during the search since they can never be otherwise.
174 */
175
176
177struct sock *__inet_lookup_listener(struct net *net,
178				    struct inet_hashinfo *hashinfo,
179				    const __be32 daddr, const unsigned short hnum,
180				    const int dif)
181{
182	struct sock *sk, *result;
183	struct hlist_nulls_node *node;
184	unsigned int hash = inet_lhashfn(net, hnum);
185	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
186	int score, hiscore;
187
188	rcu_read_lock();
189begin:
190	result = NULL;
191	hiscore = -1;
192	sk_nulls_for_each_rcu(sk, node, &ilb->head) {
193		score = compute_score(sk, net, hnum, daddr, dif);
194		if (score > hiscore) {
195			result = sk;
196			hiscore = score;
197		}
198	}
199	/*
200	 * if the nulls value we got at the end of this lookup is
201	 * not the expected one, we must restart lookup.
202	 * We probably met an item that was moved to another chain.
203	 */
204	if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
205		goto begin;
206	if (result) {
207		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
208			result = NULL;
209		else if (unlikely(compute_score(result, net, hnum, daddr,
210				  dif) < hiscore)) {
211			sock_put(result);
212			goto begin;
213		}
214	}
215	rcu_read_unlock();
216	return result;
217}
218EXPORT_SYMBOL_GPL(__inet_lookup_listener);
219
220struct sock * __inet_lookup_established(struct net *net,
221				  struct inet_hashinfo *hashinfo,
222				  const __be32 saddr, const __be16 sport,
223				  const __be32 daddr, const u16 hnum,
224				  const int dif)
225{
226	INET_ADDR_COOKIE(acookie, saddr, daddr)
227	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
228	struct sock *sk;
229	const struct hlist_nulls_node *node;
230	/* Optimize here for direct hit, only listening connections can
231	 * have wildcards anyways.
232	 */
233	unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
234	unsigned int slot = hash & hashinfo->ehash_mask;
235	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
236
237	rcu_read_lock();
238begin:
239	sk_nulls_for_each_rcu(sk, node, &head->chain) {
240		if (INET_MATCH(sk, net, hash, acookie,
241					saddr, daddr, ports, dif)) {
242			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
243				goto begintw;
244			if (unlikely(!INET_MATCH(sk, net, hash, acookie,
245				saddr, daddr, ports, dif))) {
246				sock_put(sk);
247				goto begin;
248			}
249			goto out;
250		}
251	}
252	/*
253	 * if the nulls value we got at the end of this lookup is
254	 * not the expected one, we must restart lookup.
255	 * We probably met an item that was moved to another chain.
256	 */
257	if (get_nulls_value(node) != slot)
258		goto begin;
259
260begintw:
261	/* Must check for a TIME_WAIT'er before going to listener hash. */
262	sk_nulls_for_each_rcu(sk, node, &head->twchain) {
263		if (INET_TW_MATCH(sk, net, hash, acookie,
264					saddr, daddr, ports, dif)) {
265			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
266				sk = NULL;
267				goto out;
268			}
269			if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
270				 saddr, daddr, ports, dif))) {
271				sock_put(sk);
272				goto begintw;
273			}
274			goto out;
275		}
276	}
277	/*
278	 * if the nulls value we got at the end of this lookup is
279	 * not the expected one, we must restart lookup.
280	 * We probably met an item that was moved to another chain.
281	 */
282	if (get_nulls_value(node) != slot)
283		goto begintw;
284	sk = NULL;
285out:
286	rcu_read_unlock();
287	return sk;
288}
289EXPORT_SYMBOL_GPL(__inet_lookup_established);
290
291/* called with local bh disabled */
292static int __inet_check_established(struct inet_timewait_death_row *death_row,
293				    struct sock *sk, __u16 lport,
294				    struct inet_timewait_sock **twp)
295{
296	struct inet_hashinfo *hinfo = death_row->hashinfo;
297	struct inet_sock *inet = inet_sk(sk);
298	__be32 daddr = inet->inet_rcv_saddr;
299	__be32 saddr = inet->inet_daddr;
300	int dif = sk->sk_bound_dev_if;
301	INET_ADDR_COOKIE(acookie, saddr, daddr)
302	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
303	struct net *net = sock_net(sk);
304	unsigned int hash = inet_ehashfn(net, daddr, lport,
305					 saddr, inet->inet_dport);
306	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
307	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
308	struct sock *sk2;
309	const struct hlist_nulls_node *node;
310	struct inet_timewait_sock *tw;
311	int twrefcnt = 0;
312
313	spin_lock(lock);
314
315	/* Check TIME-WAIT sockets first. */
316	sk_nulls_for_each(sk2, node, &head->twchain) {
317		tw = inet_twsk(sk2);
318
319		if (INET_TW_MATCH(sk2, net, hash, acookie,
320					saddr, daddr, ports, dif)) {
321			if (twsk_unique(sk, sk2, twp))
322				goto unique;
323			else
324				goto not_unique;
325		}
326	}
327	tw = NULL;
328
329	/* And established part... */
330	sk_nulls_for_each(sk2, node, &head->chain) {
331		if (INET_MATCH(sk2, net, hash, acookie,
332					saddr, daddr, ports, dif))
333			goto not_unique;
334	}
335
336unique:
337	/* Must record num and sport now. Otherwise we will see
338	 * in hash table socket with a funny identity. */
339	inet->inet_num = lport;
340	inet->inet_sport = htons(lport);
341	sk->sk_hash = hash;
342	WARN_ON(!sk_unhashed(sk));
343	__sk_nulls_add_node_rcu(sk, &head->chain);
344	if (tw) {
345		twrefcnt = inet_twsk_unhash(tw);
346		NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
347	}
348	spin_unlock(lock);
349	if (twrefcnt)
350		inet_twsk_put(tw);
351	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
352
353	if (twp) {
354		*twp = tw;
355	} else if (tw) {
356		/* Silly. Should hash-dance instead... */
357		inet_twsk_deschedule(tw, death_row);
358
359		inet_twsk_put(tw);
360	}
361	return 0;
362
363not_unique:
364	spin_unlock(lock);
365	return -EADDRNOTAVAIL;
366}
367
368static inline u32 inet_sk_port_offset(const struct sock *sk)
369{
370	const struct inet_sock *inet = inet_sk(sk);
371	return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
372					  inet->inet_daddr,
373					  inet->inet_dport);
374}
375
376int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
377{
378	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
379	struct hlist_nulls_head *list;
380	spinlock_t *lock;
381	struct inet_ehash_bucket *head;
382	int twrefcnt = 0;
383
384	WARN_ON(!sk_unhashed(sk));
385
386	sk->sk_hash = inet_sk_ehashfn(sk);
387	head = inet_ehash_bucket(hashinfo, sk->sk_hash);
388	list = &head->chain;
389	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
390
391	spin_lock(lock);
392	__sk_nulls_add_node_rcu(sk, list);
393	if (tw) {
394		WARN_ON(sk->sk_hash != tw->tw_hash);
395		twrefcnt = inet_twsk_unhash(tw);
396	}
397	spin_unlock(lock);
398	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
399	return twrefcnt;
400}
401EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
402
403static void __inet_hash(struct sock *sk)
404{
405	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
406	struct inet_listen_hashbucket *ilb;
407
408	if (sk->sk_state != TCP_LISTEN) {
409		__inet_hash_nolisten(sk, NULL);
410		return;
411	}
412
413	WARN_ON(!sk_unhashed(sk));
414	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
415
416	spin_lock(&ilb->lock);
417	__sk_nulls_add_node_rcu(sk, &ilb->head);
418	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
419	spin_unlock(&ilb->lock);
420}
421
422void inet_hash(struct sock *sk)
423{
424	if (sk->sk_state != TCP_CLOSE) {
425		local_bh_disable();
426		__inet_hash(sk);
427		local_bh_enable();
428	}
429}
430EXPORT_SYMBOL_GPL(inet_hash);
431
432void inet_unhash(struct sock *sk)
433{
434	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
435	spinlock_t *lock;
436	int done;
437
438	if (sk_unhashed(sk))
439		return;
440
441	if (sk->sk_state == TCP_LISTEN)
442		lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
443	else
444		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
445
446	spin_lock_bh(lock);
447	done =__sk_nulls_del_node_init_rcu(sk);
448	if (done)
449		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
450	spin_unlock_bh(lock);
451}
452EXPORT_SYMBOL_GPL(inet_unhash);
453
454int __inet_hash_connect(struct inet_timewait_death_row *death_row,
455		struct sock *sk, u32 port_offset,
456		int (*check_established)(struct inet_timewait_death_row *,
457			struct sock *, __u16, struct inet_timewait_sock **),
458		int (*hash)(struct sock *sk, struct inet_timewait_sock *twp))
459{
460	struct inet_hashinfo *hinfo = death_row->hashinfo;
461	const unsigned short snum = inet_sk(sk)->inet_num;
462	struct inet_bind_hashbucket *head;
463	struct inet_bind_bucket *tb;
464	int ret;
465	struct net *net = sock_net(sk);
466	int twrefcnt = 1;
467
468	if (!snum) {
469		int i, remaining, low, high, port;
470		static u32 hint;
471		u32 offset = hint + port_offset;
472		struct hlist_node *node;
473		struct inet_timewait_sock *tw = NULL;
474
475		inet_get_local_port_range(&low, &high);
476		remaining = (high - low) + 1;
477
478		local_bh_disable();
479		for (i = 1; i <= remaining; i++) {
480			port = low + (i + offset) % remaining;
481			if (inet_is_reserved_local_port(port))
482				continue;
483			head = &hinfo->bhash[inet_bhashfn(net, port,
484					hinfo->bhash_size)];
485			spin_lock(&head->lock);
486
487			/* Does not bother with rcv_saddr checks,
488			 * because the established check is already
489			 * unique enough.
490			 */
491			inet_bind_bucket_for_each(tb, node, &head->chain) {
492				if (net_eq(ib_net(tb), net) &&
493				    tb->port == port) {
494					if (tb->fastreuse >= 0)
495						goto next_port;
496					WARN_ON(hlist_empty(&tb->owners));
497					if (!check_established(death_row, sk,
498								port, &tw))
499						goto ok;
500					goto next_port;
501				}
502			}
503
504			tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
505					net, head, port);
506			if (!tb) {
507				spin_unlock(&head->lock);
508				break;
509			}
510			tb->fastreuse = -1;
511			goto ok;
512
513		next_port:
514			spin_unlock(&head->lock);
515		}
516		local_bh_enable();
517
518		return -EADDRNOTAVAIL;
519
520ok:
521		hint += i;
522
523		/* Head lock still held and bh's disabled */
524		inet_bind_hash(sk, tb, port);
525		if (sk_unhashed(sk)) {
526			inet_sk(sk)->inet_sport = htons(port);
527			twrefcnt += hash(sk, tw);
528		}
529		if (tw)
530			twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
531		spin_unlock(&head->lock);
532
533		if (tw) {
534			inet_twsk_deschedule(tw, death_row);
535			while (twrefcnt) {
536				twrefcnt--;
537				inet_twsk_put(tw);
538			}
539		}
540
541		ret = 0;
542		goto out;
543	}
544
545	head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
546	tb  = inet_csk(sk)->icsk_bind_hash;
547	spin_lock_bh(&head->lock);
548	if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
549		hash(sk, NULL);
550		spin_unlock_bh(&head->lock);
551		return 0;
552	} else {
553		spin_unlock(&head->lock);
554		/* No definite answer... Walk to established hash table */
555		ret = check_established(death_row, sk, snum, NULL);
556out:
557		local_bh_enable();
558		return ret;
559	}
560}
561
562/*
563 * Bind a port for a connect operation and hash it.
564 */
565int inet_hash_connect(struct inet_timewait_death_row *death_row,
566		      struct sock *sk)
567{
568	return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
569			__inet_check_established, __inet_hash_nolisten);
570}
571EXPORT_SYMBOL_GPL(inet_hash_connect);
572
573void inet_hashinfo_init(struct inet_hashinfo *h)
574{
575	int i;
576
577	atomic_set(&h->bsockets, 0);
578	for (i = 0; i < INET_LHTABLE_SIZE; i++) {
579		spin_lock_init(&h->listening_hash[i].lock);
580		INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
581				      i + LISTENING_NULLS_BASE);
582		}
583}
584EXPORT_SYMBOL_GPL(inet_hashinfo_init);

  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
 22#include <net/inet_connection_sock.h>
 23#include <net/inet_hashtables.h>
 24#include <net/secure_seq.h>
 25#include <net/ip.h>
 26
 27/*
 28 * Allocate and initialize a new local port bind bucket.
 29 * The bindhash mutex for snum's hash chain must be held here.
 30 */
 31struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
 32						 struct net *net,
 33						 struct inet_bind_hashbucket *head,
 34						 const unsigned short snum)
 35{
 36	struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
 37
 38	if (tb != NULL) {
 39		write_pnet(&tb->ib_net, hold_net(net));
 40		tb->port      = snum;
 41		tb->fastreuse = 0;
 42		tb->num_owners = 0;
 43		INIT_HLIST_HEAD(&tb->owners);
 44		hlist_add_head(&tb->node, &head->chain);
 45	}
 46	return tb;
 47}
 48
 49/*
 50 * Caller must hold hashbucket lock for this tb with local BH disabled
 51 */
 52void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
 53{
 54	if (hlist_empty(&tb->owners)) {
 55		__hlist_del(&tb->node);
 56		release_net(ib_net(tb));
 57		kmem_cache_free(cachep, tb);
 58	}
 59}
 60
 61void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
 62		    const unsigned short snum)
 63{
 64	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 65
 66	atomic_inc(&hashinfo->bsockets);
 67
 68	inet_sk(sk)->inet_num = snum;
 69	sk_add_bind_node(sk, &tb->owners);
 70	tb->num_owners++;
 71	inet_csk(sk)->icsk_bind_hash = tb;
 72}
 73
 74/*
 75 * Get rid of any references to a local port held by the given sock.
 76 */
 77static void __inet_put_port(struct sock *sk)
 78{
 79	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 80	const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
 81			hashinfo->bhash_size);
 82	struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
 83	struct inet_bind_bucket *tb;
 84
 85	atomic_dec(&hashinfo->bsockets);
 86
 87	spin_lock(&head->lock);
 88	tb = inet_csk(sk)->icsk_bind_hash;
 89	__sk_del_bind_node(sk);
 90	tb->num_owners--;
 91	inet_csk(sk)->icsk_bind_hash = NULL;
 92	inet_sk(sk)->inet_num = 0;
 93	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
 94	spin_unlock(&head->lock);
 95}
 96
 97void inet_put_port(struct sock *sk)
 98{
 99	local_bh_disable();
100	__inet_put_port(sk);
101	local_bh_enable();
102}
103EXPORT_SYMBOL(inet_put_port);
104
105int __inet_inherit_port(struct sock *sk, struct sock *child)
106{
107	struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
108	unsigned short port = inet_sk(child)->inet_num;
109	const int bhash = inet_bhashfn(sock_net(sk), port,
110			table->bhash_size);
111	struct inet_bind_hashbucket *head = &table->bhash[bhash];
112	struct inet_bind_bucket *tb;
113
114	spin_lock(&head->lock);
115	tb = inet_csk(sk)->icsk_bind_hash;
116	if (tb->port != port) {
117		/* NOTE: using tproxy and redirecting skbs to a proxy
118		 * on a different listener port breaks the assumption
119		 * that the listener socket's icsk_bind_hash is the same
120		 * as that of the child socket. We have to look up or
121		 * create a new bind bucket for the child here. */
122		struct hlist_node *node;
123		inet_bind_bucket_for_each(tb, node, &head->chain) {
124			if (net_eq(ib_net(tb), sock_net(sk)) &&
125			    tb->port == port)
126				break;
127		}
128		if (!node) {
129			tb = inet_bind_bucket_create(table->bind_bucket_cachep,
130						     sock_net(sk), head, port);
131			if (!tb) {
132				spin_unlock(&head->lock);
133				return -ENOMEM;
134			}
135		}
136	}
137	inet_bind_hash(child, tb, port);
138	spin_unlock(&head->lock);
139
140	return 0;
141}
142EXPORT_SYMBOL_GPL(__inet_inherit_port);
143
144static inline int compute_score(struct sock *sk, struct net *net,
145				const unsigned short hnum, const __be32 daddr,
146				const int dif)
147{
148	int score = -1;
149	struct inet_sock *inet = inet_sk(sk);
150
151	if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
152			!ipv6_only_sock(sk)) {
153		__be32 rcv_saddr = inet->inet_rcv_saddr;
154		score = sk->sk_family == PF_INET ? 1 : 0;
155		if (rcv_saddr) {
156			if (rcv_saddr != daddr)
157				return -1;
158			score += 2;
159		}
160		if (sk->sk_bound_dev_if) {
161			if (sk->sk_bound_dev_if != dif)
162				return -1;
163			score += 2;
164		}
165	}
166	return score;
167}
168
169/*
170 * Don't inline this cruft. Here are some nice properties to exploit here. The
171 * BSD API does not allow a listening sock to specify the remote port nor the
172 * remote address for the connection. So always assume those are both
173 * wildcarded during the search since they can never be otherwise.
174 */
175
176
177struct sock *__inet_lookup_listener(struct net *net,
178				    struct inet_hashinfo *hashinfo,
179				    const __be32 daddr, const unsigned short hnum,
180				    const int dif)
181{
182	struct sock *sk, *result;
183	struct hlist_nulls_node *node;
184	unsigned int hash = inet_lhashfn(net, hnum);
185	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
186	int score, hiscore;
187
188	rcu_read_lock();
189begin:
190	result = NULL;
191	hiscore = -1;
192	sk_nulls_for_each_rcu(sk, node, &ilb->head) {
193		score = compute_score(sk, net, hnum, daddr, dif);
194		if (score > hiscore) {
195			result = sk;
196			hiscore = score;
197		}
198	}
199	/*
200	 * if the nulls value we got at the end of this lookup is
201	 * not the expected one, we must restart lookup.
202	 * We probably met an item that was moved to another chain.
203	 */
204	if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
205		goto begin;
206	if (result) {
207		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
208			result = NULL;
209		else if (unlikely(compute_score(result, net, hnum, daddr,
210				  dif) < hiscore)) {
211			sock_put(result);
212			goto begin;
213		}
214	}
215	rcu_read_unlock();
216	return result;
217}
218EXPORT_SYMBOL_GPL(__inet_lookup_listener);
219
220struct sock *__inet_lookup_established(struct net *net,
221				  struct inet_hashinfo *hashinfo,
222				  const __be32 saddr, const __be16 sport,
223				  const __be32 daddr, const u16 hnum,
224				  const int dif)
225{
226	INET_ADDR_COOKIE(acookie, saddr, daddr)
227	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
228	struct sock *sk;
229	const struct hlist_nulls_node *node;
230	/* Optimize here for direct hit, only listening connections can
231	 * have wildcards anyways.
232	 */
233	unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
234	unsigned int slot = hash & hashinfo->ehash_mask;
235	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
236
237	rcu_read_lock();
238begin:
239	sk_nulls_for_each_rcu(sk, node, &head->chain) {
240		if (INET_MATCH(sk, net, hash, acookie,
241					saddr, daddr, ports, dif)) {
242			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
243				goto begintw;
244			if (unlikely(!INET_MATCH(sk, net, hash, acookie,
245				saddr, daddr, ports, dif))) {
246				sock_put(sk);
247				goto begin;
248			}
249			goto out;
250		}
251	}
252	/*
253	 * if the nulls value we got at the end of this lookup is
254	 * not the expected one, we must restart lookup.
255	 * We probably met an item that was moved to another chain.
256	 */
257	if (get_nulls_value(node) != slot)
258		goto begin;
259
260begintw:
261	/* Must check for a TIME_WAIT'er before going to listener hash. */
262	sk_nulls_for_each_rcu(sk, node, &head->twchain) {
263		if (INET_TW_MATCH(sk, net, hash, acookie,
264					saddr, daddr, ports, dif)) {
265			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
266				sk = NULL;
267				goto out;
268			}
269			if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
270				 saddr, daddr, ports, dif))) {
271				sock_put(sk);
272				goto begintw;
273			}
274			goto out;
275		}
276	}
277	/*
278	 * if the nulls value we got at the end of this lookup is
279	 * not the expected one, we must restart lookup.
280	 * We probably met an item that was moved to another chain.
281	 */
282	if (get_nulls_value(node) != slot)
283		goto begintw;
284	sk = NULL;
285out:
286	rcu_read_unlock();
287	return sk;
288}
289EXPORT_SYMBOL_GPL(__inet_lookup_established);
290
291/* called with local bh disabled */
292static int __inet_check_established(struct inet_timewait_death_row *death_row,
293				    struct sock *sk, __u16 lport,
294				    struct inet_timewait_sock **twp)
295{
296	struct inet_hashinfo *hinfo = death_row->hashinfo;
297	struct inet_sock *inet = inet_sk(sk);
298	__be32 daddr = inet->inet_rcv_saddr;
299	__be32 saddr = inet->inet_daddr;
300	int dif = sk->sk_bound_dev_if;
301	INET_ADDR_COOKIE(acookie, saddr, daddr)
302	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
303	struct net *net = sock_net(sk);
304	unsigned int hash = inet_ehashfn(net, daddr, lport,
305					 saddr, inet->inet_dport);
306	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
307	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
308	struct sock *sk2;
309	const struct hlist_nulls_node *node;
310	struct inet_timewait_sock *tw;
311	int twrefcnt = 0;
312
313	spin_lock(lock);
314
315	/* Check TIME-WAIT sockets first. */
316	sk_nulls_for_each(sk2, node, &head->twchain) {
317		tw = inet_twsk(sk2);
318
319		if (INET_TW_MATCH(sk2, net, hash, acookie,
320					saddr, daddr, ports, dif)) {
321			if (twsk_unique(sk, sk2, twp))
322				goto unique;
323			else
324				goto not_unique;
325		}
326	}
327	tw = NULL;
328
329	/* And established part... */
330	sk_nulls_for_each(sk2, node, &head->chain) {
331		if (INET_MATCH(sk2, net, hash, acookie,
332					saddr, daddr, ports, dif))
333			goto not_unique;
334	}
335
336unique:
337	/* Must record num and sport now. Otherwise we will see
338	 * in hash table socket with a funny identity. */
339	inet->inet_num = lport;
340	inet->inet_sport = htons(lport);
341	sk->sk_hash = hash;
342	WARN_ON(!sk_unhashed(sk));
343	__sk_nulls_add_node_rcu(sk, &head->chain);
344	if (tw) {
345		twrefcnt = inet_twsk_unhash(tw);
346		NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
347	}
348	spin_unlock(lock);
349	if (twrefcnt)
350		inet_twsk_put(tw);
351	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
352
353	if (twp) {
354		*twp = tw;
355	} else if (tw) {
356		/* Silly. Should hash-dance instead... */
357		inet_twsk_deschedule(tw, death_row);
358
359		inet_twsk_put(tw);
360	}
361	return 0;
362
363not_unique:
364	spin_unlock(lock);
365	return -EADDRNOTAVAIL;
366}
367
368static inline u32 inet_sk_port_offset(const struct sock *sk)
369{
370	const struct inet_sock *inet = inet_sk(sk);
371	return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
372					  inet->inet_daddr,
373					  inet->inet_dport);
374}
375
376int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
377{
378	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
379	struct hlist_nulls_head *list;
380	spinlock_t *lock;
381	struct inet_ehash_bucket *head;
382	int twrefcnt = 0;
383
384	WARN_ON(!sk_unhashed(sk));
385
386	sk->sk_hash = inet_sk_ehashfn(sk);
387	head = inet_ehash_bucket(hashinfo, sk->sk_hash);
388	list = &head->chain;
389	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
390
391	spin_lock(lock);
392	__sk_nulls_add_node_rcu(sk, list);
393	if (tw) {
394		WARN_ON(sk->sk_hash != tw->tw_hash);
395		twrefcnt = inet_twsk_unhash(tw);
396	}
397	spin_unlock(lock);
398	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
399	return twrefcnt;
400}
401EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
402
403static void __inet_hash(struct sock *sk)
404{
405	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
406	struct inet_listen_hashbucket *ilb;
407
408	if (sk->sk_state != TCP_LISTEN) {
409		__inet_hash_nolisten(sk, NULL);
410		return;
411	}
412
413	WARN_ON(!sk_unhashed(sk));
414	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
415
416	spin_lock(&ilb->lock);
417	__sk_nulls_add_node_rcu(sk, &ilb->head);
418	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
419	spin_unlock(&ilb->lock);
420}
421
422void inet_hash(struct sock *sk)
423{
424	if (sk->sk_state != TCP_CLOSE) {
425		local_bh_disable();
426		__inet_hash(sk);
427		local_bh_enable();
428	}
429}
430EXPORT_SYMBOL_GPL(inet_hash);
431
432void inet_unhash(struct sock *sk)
433{
434	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
435	spinlock_t *lock;
436	int done;
437
438	if (sk_unhashed(sk))
439		return;
440
441	if (sk->sk_state == TCP_LISTEN)
442		lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
443	else
444		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
445
446	spin_lock_bh(lock);
447	done =__sk_nulls_del_node_init_rcu(sk);
448	if (done)
449		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
450	spin_unlock_bh(lock);
451}
452EXPORT_SYMBOL_GPL(inet_unhash);
453
454int __inet_hash_connect(struct inet_timewait_death_row *death_row,
455		struct sock *sk, u32 port_offset,
456		int (*check_established)(struct inet_timewait_death_row *,
457			struct sock *, __u16, struct inet_timewait_sock **),
458		int (*hash)(struct sock *sk, struct inet_timewait_sock *twp))
459{
460	struct inet_hashinfo *hinfo = death_row->hashinfo;
461	const unsigned short snum = inet_sk(sk)->inet_num;
462	struct inet_bind_hashbucket *head;
463	struct inet_bind_bucket *tb;
464	int ret;
465	struct net *net = sock_net(sk);
466	int twrefcnt = 1;
467
468	if (!snum) {
469		int i, remaining, low, high, port;
470		static u32 hint;
471		u32 offset = hint + port_offset;
472		struct hlist_node *node;
473		struct inet_timewait_sock *tw = NULL;
474
475		inet_get_local_port_range(&low, &high);
476		remaining = (high - low) + 1;
477
478		local_bh_disable();
479		for (i = 1; i <= remaining; i++) {
480			port = low + (i + offset) % remaining;
481			if (inet_is_reserved_local_port(port))
482				continue;
483			head = &hinfo->bhash[inet_bhashfn(net, port,
484					hinfo->bhash_size)];
485			spin_lock(&head->lock);
486
487			/* Does not bother with rcv_saddr checks,
488			 * because the established check is already
489			 * unique enough.
490			 */
491			inet_bind_bucket_for_each(tb, node, &head->chain) {
492				if (net_eq(ib_net(tb), net) &&
493				    tb->port == port) {
494					if (tb->fastreuse >= 0)
495						goto next_port;
496					WARN_ON(hlist_empty(&tb->owners));
497					if (!check_established(death_row, sk,
498								port, &tw))
499						goto ok;
500					goto next_port;
501				}
502			}
503
504			tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
505					net, head, port);
506			if (!tb) {
507				spin_unlock(&head->lock);
508				break;
509			}
510			tb->fastreuse = -1;
511			goto ok;
512
513		next_port:
514			spin_unlock(&head->lock);
515		}
516		local_bh_enable();
517
518		return -EADDRNOTAVAIL;
519
520ok:
521		hint += i;
522
523		/* Head lock still held and bh's disabled */
524		inet_bind_hash(sk, tb, port);
525		if (sk_unhashed(sk)) {
526			inet_sk(sk)->inet_sport = htons(port);
527			twrefcnt += hash(sk, tw);
528		}
529		if (tw)
530			twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
531		spin_unlock(&head->lock);
532
533		if (tw) {
534			inet_twsk_deschedule(tw, death_row);
535			while (twrefcnt) {
536				twrefcnt--;
537				inet_twsk_put(tw);
538			}
539		}
540
541		ret = 0;
542		goto out;
543	}
544
545	head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
546	tb  = inet_csk(sk)->icsk_bind_hash;
547	spin_lock_bh(&head->lock);
548	if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
549		hash(sk, NULL);
550		spin_unlock_bh(&head->lock);
551		return 0;
552	} else {
553		spin_unlock(&head->lock);
554		/* No definite answer... Walk to established hash table */
555		ret = check_established(death_row, sk, snum, NULL);
556out:
557		local_bh_enable();
558		return ret;
559	}
560}
561
562/*
563 * Bind a port for a connect operation and hash it.
564 */
565int inet_hash_connect(struct inet_timewait_death_row *death_row,
566		      struct sock *sk)
567{
568	return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
569			__inet_check_established, __inet_hash_nolisten);
570}
571EXPORT_SYMBOL_GPL(inet_hash_connect);
572
573void inet_hashinfo_init(struct inet_hashinfo *h)
574{
575	int i;
576
577	atomic_set(&h->bsockets, 0);
578	for (i = 0; i < INET_LHTABLE_SIZE; i++) {
579		spin_lock_init(&h->listening_hash[i].lock);
580		INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
581				      i + LISTENING_NULLS_BASE);
582		}
583}
584EXPORT_SYMBOL_GPL(inet_hashinfo_init);