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);