1 // SPDX-License-Identifier: GPL-2.0-only
3  * INET		An implementation of the TCP/IP protocol suite for the LINUX
5  *		interface as the means of communication with the user level.
21  *	inet_twsk_bind_unhash - unhash a timewait socket from bind hash
26  *	bind hash lock must be held by caller.
27  *	Returns 1 if caller should call inet_twsk_put() after lock release.
32 	struct inet_bind2_bucket *tb2 = tw->tw_tb2;  in inet_twsk_bind_unhash()
33 	struct inet_bind_bucket *tb = tw->tw_tb;  in inet_twsk_bind_unhash()
39 	tw->tw_tb = NULL;  in inet_twsk_bind_unhash()
40 	tw->tw_tb2 = NULL;  in inet_twsk_bind_unhash()
41 	inet_bind2_bucket_destroy(hashinfo->bind2_bucket_cachep, tb2);  in inet_twsk_bind_unhash()
42 	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);  in inet_twsk_bind_unhash()
50 	struct inet_hashinfo *hashinfo = tw->tw_dr->hashinfo;  in inet_twsk_kill()
51 	spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);  in inet_twsk_kill()  local
54 	spin_lock(lock);  in inet_twsk_kill()
56 	spin_unlock(lock);  in inet_twsk_kill()
59 	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num,  in inet_twsk_kill()
60 			hashinfo->bhash_size)];  in inet_twsk_kill()
62 				       twsk_net(tw), tw->tw_num);  in inet_twsk_kill()
64 	spin_lock(&bhead->lock);  in inet_twsk_kill()
65 	spin_lock(&bhead2->lock);  in inet_twsk_kill()
67 	spin_unlock(&bhead2->lock);  in inet_twsk_kill()
68 	spin_unlock(&bhead->lock);  in inet_twsk_kill()
70 	refcount_dec(&tw->tw_dr->tw_refcount);  in inet_twsk_kill()
76 	struct module *owner = tw->tw_prot->owner;  in inet_twsk_free()
78 	kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw);  in inet_twsk_free()
84 	if (refcount_dec_and_test(&tw->tw_refcnt))  in inet_twsk_put()
92 	hlist_nulls_add_head_rcu(&tw->tw_node, list);  in inet_twsk_add_node_rcu()
114 	struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash);  in inet_twsk_hashdance_schedule()
115 	spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);  in inet_twsk_hashdance_schedule()  local
119 	   Note, that any socket with inet->num != 0 MUST be bound in  in inet_twsk_hashdance_schedule()
122 	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num,  in inet_twsk_hashdance_schedule()
123 			hashinfo->bhash_size)];  in inet_twsk_hashdance_schedule()
124 	bhead2 = inet_bhashfn_portaddr(hashinfo, sk, twsk_net(tw), inet->inet_num);  in inet_twsk_hashdance_schedule()
127 	spin_lock(&bhead->lock);  in inet_twsk_hashdance_schedule()
128 	spin_lock(&bhead2->lock);  in inet_twsk_hashdance_schedule()
130 	tw->tw_tb = icsk->icsk_bind_hash;  in inet_twsk_hashdance_schedule()
131 	WARN_ON(!icsk->icsk_bind_hash);  in inet_twsk_hashdance_schedule()
133 	tw->tw_tb2 = icsk->icsk_bind2_hash;  in inet_twsk_hashdance_schedule()
134 	WARN_ON(!icsk->icsk_bind2_hash);  in inet_twsk_hashdance_schedule()
135 	sk_add_bind_node((struct sock *)tw, &tw->tw_tb2->owners);  in inet_twsk_hashdance_schedule()
137 	spin_unlock(&bhead2->lock);  in inet_twsk_hashdance_schedule()
138 	spin_unlock(&bhead->lock);  in inet_twsk_hashdance_schedule()
140 	spin_lock(lock);  in inet_twsk_hashdance_schedule()
143 	inet_twsk_add_node_rcu(tw, &ehead->chain);  in inet_twsk_hashdance_schedule()
147 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);  in inet_twsk_hashdance_schedule()
156 	 * - one reference for bhash chain.  in inet_twsk_hashdance_schedule()
157 	 * - one reference for ehash chain.  in inet_twsk_hashdance_schedule()
158 	 * - one reference for timer.  in inet_twsk_hashdance_schedule()
162 	refcount_set(&tw->tw_refcnt, 3);  in inet_twsk_hashdance_schedule()
166 	spin_unlock(lock);  in inet_twsk_hashdance_schedule()
184 	if (refcount_read(&dr->tw_refcount) - 1 >=  in inet_twsk_alloc()
185 	    READ_ONCE(dr->sysctl_max_tw_buckets))  in inet_twsk_alloc()
188 	tw = kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab,  in inet_twsk_alloc()
193 		tw->tw_dr	    = dr;  in inet_twsk_alloc()
195 		tw->tw_daddr	    = inet->inet_daddr;  in inet_twsk_alloc()
196 		tw->tw_rcv_saddr    = inet->inet_rcv_saddr;  in inet_twsk_alloc()
197 		tw->tw_bound_dev_if = sk->sk_bound_dev_if;  in inet_twsk_alloc()
198 		tw->tw_tos	    = inet->tos;  in inet_twsk_alloc()
199 		tw->tw_num	    = inet->inet_num;  in inet_twsk_alloc()
200 		tw->tw_state	    = TCP_TIME_WAIT;  in inet_twsk_alloc()
201 		tw->tw_substate	    = state;  in inet_twsk_alloc()
202 		tw->tw_sport	    = inet->inet_sport;  in inet_twsk_alloc()
203 		tw->tw_dport	    = inet->inet_dport;  in inet_twsk_alloc()
204 		tw->tw_family	    = sk->sk_family;  in inet_twsk_alloc()
205 		tw->tw_reuse	    = sk->sk_reuse;  in inet_twsk_alloc()
206 		tw->tw_reuseport    = sk->sk_reuseport;  in inet_twsk_alloc()
207 		tw->tw_hash	    = sk->sk_hash;  in inet_twsk_alloc()
208 		tw->tw_ipv6only	    = 0;  in inet_twsk_alloc()
209 		tw->tw_transparent  = inet_test_bit(TRANSPARENT, sk);  in inet_twsk_alloc()
210 		tw->tw_prot	    = sk->sk_prot_creator;  in inet_twsk_alloc()
211 		atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie));  in inet_twsk_alloc()
213 		timer_setup(&tw->tw_timer, tw_timer_handler, 0);  in inet_twsk_alloc()
219 		refcount_set(&tw->tw_refcnt, 0);  in inet_twsk_alloc()
221 		__module_get(tw->tw_prot->owner);  in inet_twsk_alloc()
232 /* This is for handling early-kills of TIME_WAIT sockets.
238 	struct inet_hashinfo *hashinfo = tw->tw_dr->hashinfo;  in inet_twsk_deschedule_put()
239 	spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);  in inet_twsk_deschedule_put()  local
249 	 * The ehash lock synchronizes these two:  in inet_twsk_deschedule_put()
250 	 * After acquiring the lock, the timer is always scheduled (else  in inet_twsk_deschedule_put()
252 	 * the ehash lock only after completing the timer initialization.  in inet_twsk_deschedule_put()
254 	 * Without grabbing the ehash lock, we get:  in inet_twsk_deschedule_put()
258 	 * 4) cpu x tries to start timer, but mod_timer is a noop post-shutdown  in inet_twsk_deschedule_put()
259 	 * -> timer refcount is never decremented.  in inet_twsk_deschedule_put()
261 	spin_lock(lock);  in inet_twsk_deschedule_put()
263 	spin_unlock(lock);  in inet_twsk_deschedule_put()
265 	if (timer_shutdown_sync(&tw->tw_timer))  in inet_twsk_deschedule_put()
277 	 * RATIONALE: if FIN arrived and we entered TIME-WAIT state,  in __inet_twsk_schedule()
279 	 * FINs (or previous seqments) are lost (probability of such event  in __inet_twsk_schedule()
281 	 * time to detect the loss is about RTO*(2^N - 1) with exponential  in __inet_twsk_schedule()
286 	 *   Well, 240 consumes too much of resources 8)  in __inet_twsk_schedule()
295 	 * of PAWS.  in __inet_twsk_schedule()
303 		BUG_ON(mod_timer(&tw->tw_timer, jiffies + timeo));  in __inet_twsk_schedule()
304 		refcount_inc(&tw->tw_dr->tw_refcount);  in __inet_twsk_schedule()
306 		mod_timer_pending(&tw->tw_timer, jiffies + timeo);  in __inet_twsk_schedule()
314 	struct inet_ehash_bucket *head = &hashinfo->ehash[0];  in inet_twsk_purge()
315 	unsigned int ehash_mask = hashinfo->ehash_mask;  in inet_twsk_purge()
321 		if (hlist_nulls_empty(&head->chain))  in inet_twsk_purge()
328 		sk_nulls_for_each_rcu(sk, node, &head->chain) {  in inet_twsk_purge()
335 			if (refcount_read(&sock_net(sk)->ns.count))  in inet_twsk_purge()
338 			if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))  in inet_twsk_purge()
341 			if (refcount_read(&sock_net(sk)->ns.count)) {  in inet_twsk_purge()
353 				inet_csk_reqsk_queue_drop_and_put(req->rsk_listener,  in inet_twsk_purge()
359 		/* If the nulls value we got at the end of this lookup is  in inet_twsk_purge()