1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2e48c414eSArnaldo Carvalho de Melo /* 3e48c414eSArnaldo Carvalho de Melo * INET An implementation of the TCP/IP protocol suite for the LINUX 4e48c414eSArnaldo Carvalho de Melo * operating system. INET is implemented using the BSD Socket 5e48c414eSArnaldo Carvalho de Melo * interface as the means of communication with the user level. 6e48c414eSArnaldo Carvalho de Melo * 7e48c414eSArnaldo Carvalho de Melo * Generic TIME_WAIT sockets functions 8e48c414eSArnaldo Carvalho de Melo * 9e48c414eSArnaldo Carvalho de Melo * From code orinally in TCP 10e48c414eSArnaldo Carvalho de Melo */ 11e48c414eSArnaldo Carvalho de Melo 12172589ccSIlpo Järvinen #include <linux/kernel.h> 135a0e3ad6STejun Heo #include <linux/slab.h> 143a9a231dSPaul Gortmaker #include <linux/module.h> 15e48c414eSArnaldo Carvalho de Melo #include <net/inet_hashtables.h> 16e48c414eSArnaldo Carvalho de Melo #include <net/inet_timewait_sock.h> 17696ab2d3SArnaldo Carvalho de Melo #include <net/ip.h> 18e48c414eSArnaldo Carvalho de Melo 1913475a30SEric Dumazet 202a8875e7SEric Dumazet /** 212a8875e7SEric Dumazet * inet_twsk_bind_unhash - unhash a timewait socket from bind hash 222a8875e7SEric Dumazet * @tw: timewait socket 232a8875e7SEric Dumazet * @hashinfo: hashinfo pointer 242a8875e7SEric Dumazet * 252a8875e7SEric Dumazet * unhash a timewait socket from bind hash, if hashed. 262a8875e7SEric Dumazet * bind hash lock must be held by caller. 272a8875e7SEric Dumazet * Returns 1 if caller should call inet_twsk_put() after lock release. 283cdaedaeSEric Dumazet */ 29fc01538fSEric Dumazet void inet_twsk_bind_unhash(struct inet_timewait_sock *tw, 303cdaedaeSEric Dumazet struct inet_hashinfo *hashinfo) 313cdaedaeSEric Dumazet { 32936a192fSKuniyuki Iwashima struct inet_bind2_bucket *tb2 = tw->tw_tb2; 333cdaedaeSEric Dumazet struct inet_bind_bucket *tb = tw->tw_tb; 343cdaedaeSEric Dumazet 353cdaedaeSEric Dumazet if (!tb) 36fc01538fSEric Dumazet return; 373cdaedaeSEric Dumazet 38*770041d3SKuniyuki Iwashima __sk_del_bind_node((struct sock *)tw); 393cdaedaeSEric Dumazet tw->tw_tb = NULL; 40936a192fSKuniyuki Iwashima tw->tw_tb2 = NULL; 41936a192fSKuniyuki Iwashima inet_bind2_bucket_destroy(hashinfo->bind2_bucket_cachep, tb2); 428002d44fSKuniyuki Iwashima inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); 43936a192fSKuniyuki Iwashima 44fc01538fSEric Dumazet __sock_put((struct sock *)tw); 453cdaedaeSEric Dumazet } 463cdaedaeSEric Dumazet 47e48c414eSArnaldo Carvalho de Melo /* Must be called with locally disabled BHs. */ 48789f558cSEric Dumazet static void inet_twsk_kill(struct inet_timewait_sock *tw) 49e48c414eSArnaldo Carvalho de Melo { 50789f558cSEric Dumazet struct inet_hashinfo *hashinfo = tw->tw_dr->hashinfo; 519db66bdcSEric Dumazet spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash); 52936a192fSKuniyuki Iwashima struct inet_bind_hashbucket *bhead, *bhead2; 53e48c414eSArnaldo Carvalho de Melo 549db66bdcSEric Dumazet spin_lock(lock); 55fc01538fSEric Dumazet sk_nulls_del_node_init_rcu((struct sock *)tw); 569db66bdcSEric Dumazet spin_unlock(lock); 57e48c414eSArnaldo Carvalho de Melo 58e48c414eSArnaldo Carvalho de Melo /* Disassociate with bind bucket. */ 5904c494e6SEric Dumazet bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num, 6004c494e6SEric Dumazet hashinfo->bhash_size)]; 61936a192fSKuniyuki Iwashima bhead2 = inet_bhashfn_portaddr(hashinfo, (struct sock *)tw, 62936a192fSKuniyuki Iwashima twsk_net(tw), tw->tw_num); 633cdaedaeSEric Dumazet 64e48c414eSArnaldo Carvalho de Melo spin_lock(&bhead->lock); 65936a192fSKuniyuki Iwashima spin_lock(&bhead2->lock); 66fc01538fSEric Dumazet inet_twsk_bind_unhash(tw, hashinfo); 67936a192fSKuniyuki Iwashima spin_unlock(&bhead2->lock); 68e48c414eSArnaldo Carvalho de Melo spin_unlock(&bhead->lock); 693cdaedaeSEric Dumazet 70e9bd0ccaSKuniyuki Iwashima refcount_dec(&tw->tw_dr->tw_refcount); 71789f558cSEric Dumazet inet_twsk_put(tw); 72e48c414eSArnaldo Carvalho de Melo } 73e48c414eSArnaldo Carvalho de Melo 7405dbc7b5SEric Dumazet void inet_twsk_free(struct inet_timewait_sock *tw) 757054fb93SPavel Emelyanov { 767054fb93SPavel Emelyanov struct module *owner = tw->tw_prot->owner; 777054fb93SPavel Emelyanov twsk_destructor((struct sock *)tw); 787054fb93SPavel Emelyanov kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw); 797054fb93SPavel Emelyanov module_put(owner); 807054fb93SPavel Emelyanov } 814dbc8ef7SArnaldo Carvalho de Melo 824dbc8ef7SArnaldo Carvalho de Melo void inet_twsk_put(struct inet_timewait_sock *tw) 834dbc8ef7SArnaldo Carvalho de Melo { 8441c6d650SReshetova, Elena if (refcount_dec_and_test(&tw->tw_refcnt)) 854dbc8ef7SArnaldo Carvalho de Melo inet_twsk_free(tw); 867054fb93SPavel Emelyanov } 877054fb93SPavel Emelyanov EXPORT_SYMBOL_GPL(inet_twsk_put); 887054fb93SPavel Emelyanov 8981b3ade5SKuniyuki Iwashima static void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw, 9005dbc7b5SEric Dumazet struct hlist_nulls_head *list) 9105dbc7b5SEric Dumazet { 9281b3ade5SKuniyuki Iwashima hlist_nulls_add_head_rcu(&tw->tw_node, list); 9305dbc7b5SEric Dumazet } 9405dbc7b5SEric Dumazet 95e48c414eSArnaldo Carvalho de Melo /* 96e599ea14SEric Dumazet * Enter the time wait state. This is called with locally disabled BH. 97e48c414eSArnaldo Carvalho de Melo * Essentially we whip up a timewait bucket, copy the relevant info into it 98e48c414eSArnaldo Carvalho de Melo * from the SK, and mess with hash chains and list linkage. 99e48c414eSArnaldo Carvalho de Melo */ 100ec94c269SEric Dumazet void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk, 101e48c414eSArnaldo Carvalho de Melo struct inet_hashinfo *hashinfo) 102e48c414eSArnaldo Carvalho de Melo { 103e48c414eSArnaldo Carvalho de Melo const struct inet_sock *inet = inet_sk(sk); 104463c84b9SArnaldo Carvalho de Melo const struct inet_connection_sock *icsk = inet_csk(sk); 10581c3d547SEric Dumazet struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash); 1069db66bdcSEric Dumazet spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash); 107936a192fSKuniyuki Iwashima struct inet_bind_hashbucket *bhead, *bhead2; 108936a192fSKuniyuki Iwashima 109e48c414eSArnaldo Carvalho de Melo /* Step 1: Put TW into bind hash. Original socket stays there too. 110e48c414eSArnaldo Carvalho de Melo Note, that any socket with inet->num != 0 MUST be bound in 111e48c414eSArnaldo Carvalho de Melo binding cache, even if it is closed. 112e48c414eSArnaldo Carvalho de Melo */ 11304c494e6SEric Dumazet bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num, 11404c494e6SEric Dumazet hashinfo->bhash_size)]; 115936a192fSKuniyuki Iwashima bhead2 = inet_bhashfn_portaddr(hashinfo, sk, twsk_net(tw), inet->inet_num); 116936a192fSKuniyuki Iwashima 117e599ea14SEric Dumazet spin_lock(&bhead->lock); 118936a192fSKuniyuki Iwashima spin_lock(&bhead2->lock); 119936a192fSKuniyuki Iwashima 120463c84b9SArnaldo Carvalho de Melo tw->tw_tb = icsk->icsk_bind_hash; 121547b792cSIlpo Järvinen WARN_ON(!icsk->icsk_bind_hash); 122936a192fSKuniyuki Iwashima 123936a192fSKuniyuki Iwashima tw->tw_tb2 = icsk->icsk_bind2_hash; 124936a192fSKuniyuki Iwashima WARN_ON(!icsk->icsk_bind2_hash); 125*770041d3SKuniyuki Iwashima sk_add_bind_node((struct sock *)tw, &tw->tw_tb2->owners); 126936a192fSKuniyuki Iwashima 127936a192fSKuniyuki Iwashima spin_unlock(&bhead2->lock); 128e48c414eSArnaldo Carvalho de Melo spin_unlock(&bhead->lock); 129e48c414eSArnaldo Carvalho de Melo 1309db66bdcSEric Dumazet spin_lock(lock); 131e48c414eSArnaldo Carvalho de Melo 13281b3ade5SKuniyuki Iwashima inet_twsk_add_node_rcu(tw, &ehead->chain); 1333ab5aee7SEric Dumazet 13405dbc7b5SEric Dumazet /* Step 3: Remove SK from hash chain */ 1353ab5aee7SEric Dumazet if (__sk_nulls_del_node_init_rcu(sk)) 1363ab5aee7SEric Dumazet sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 137e48c414eSArnaldo Carvalho de Melo 138e599ea14SEric Dumazet spin_unlock(lock); 139ec94c269SEric Dumazet 140ec94c269SEric Dumazet /* tw_refcnt is set to 3 because we have : 141ec94c269SEric Dumazet * - one reference for bhash chain. 142ec94c269SEric Dumazet * - one reference for ehash chain. 143ec94c269SEric Dumazet * - one reference for timer. 144ec94c269SEric Dumazet * We can use atomic_set() because prior spin_lock()/spin_unlock() 145ec94c269SEric Dumazet * committed into memory all tw fields. 146ec94c269SEric Dumazet * Also note that after this point, we lost our implicit reference 147ec94c269SEric Dumazet * so we are not allowed to use tw anymore. 148ec94c269SEric Dumazet */ 149ec94c269SEric Dumazet refcount_set(&tw->tw_refcnt, 3); 150e48c414eSArnaldo Carvalho de Melo } 151ec94c269SEric Dumazet EXPORT_SYMBOL_GPL(inet_twsk_hashdance); 152696ab2d3SArnaldo Carvalho de Melo 1531ab791dcSKees Cook static void tw_timer_handler(struct timer_list *t) 154c676270bSArnaldo Carvalho de Melo { 1551ab791dcSKees Cook struct inet_timewait_sock *tw = from_timer(tw, t, tw_timer); 156789f558cSEric Dumazet 157789f558cSEric Dumazet inet_twsk_kill(tw); 158789f558cSEric Dumazet } 159789f558cSEric Dumazet 160789f558cSEric Dumazet struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, 161789f558cSEric Dumazet struct inet_timewait_death_row *dr, 162789f558cSEric Dumazet const int state) 163789f558cSEric Dumazet { 164789f558cSEric Dumazet struct inet_timewait_sock *tw; 165789f558cSEric Dumazet 1666f605b57SKuniyuki Iwashima if (refcount_read(&dr->tw_refcount) - 1 >= 1676f605b57SKuniyuki Iwashima READ_ONCE(dr->sysctl_max_tw_buckets)) 168789f558cSEric Dumazet return NULL; 169789f558cSEric Dumazet 170789f558cSEric Dumazet tw = kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab, 17154e6ecb2SChristoph Lameter GFP_ATOMIC); 17200db4124SIan Morris if (tw) { 173c676270bSArnaldo Carvalho de Melo const struct inet_sock *inet = inet_sk(sk); 174c676270bSArnaldo Carvalho de Melo 175789f558cSEric Dumazet tw->tw_dr = dr; 176c676270bSArnaldo Carvalho de Melo /* Give us an identity. */ 177c720c7e8SEric Dumazet tw->tw_daddr = inet->inet_daddr; 178c720c7e8SEric Dumazet tw->tw_rcv_saddr = inet->inet_rcv_saddr; 179c676270bSArnaldo Carvalho de Melo tw->tw_bound_dev_if = sk->sk_bound_dev_if; 18066b13d99SEric Dumazet tw->tw_tos = inet->tos; 181c720c7e8SEric Dumazet tw->tw_num = inet->inet_num; 182c676270bSArnaldo Carvalho de Melo tw->tw_state = TCP_TIME_WAIT; 183c676270bSArnaldo Carvalho de Melo tw->tw_substate = state; 184c720c7e8SEric Dumazet tw->tw_sport = inet->inet_sport; 185c720c7e8SEric Dumazet tw->tw_dport = inet->inet_dport; 186c676270bSArnaldo Carvalho de Melo tw->tw_family = sk->sk_family; 187c676270bSArnaldo Carvalho de Melo tw->tw_reuse = sk->sk_reuse; 1883099a529SEric Dumazet tw->tw_reuseport = sk->sk_reuseport; 18981c3d547SEric Dumazet tw->tw_hash = sk->sk_hash; 190c676270bSArnaldo Carvalho de Melo tw->tw_ipv6only = 0; 1914bd0623fSEric Dumazet tw->tw_transparent = inet_test_bit(TRANSPARENT, sk); 192c676270bSArnaldo Carvalho de Melo tw->tw_prot = sk->sk_prot_creator; 19333cf7c90SEric Dumazet atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie)); 194efd7ef1cSEric W. Biederman twsk_net_set(tw, sock_net(sk)); 1951ab791dcSKees Cook timer_setup(&tw->tw_timer, tw_timer_handler, TIMER_PINNED); 19647e1c323SEric Dumazet /* 19747e1c323SEric Dumazet * Because we use RCU lookups, we should not set tw_refcnt 19847e1c323SEric Dumazet * to a non null value before everything is setup for this 19947e1c323SEric Dumazet * timewait socket. 20047e1c323SEric Dumazet */ 20141c6d650SReshetova, Elena refcount_set(&tw->tw_refcnt, 0); 202789f558cSEric Dumazet 203eeb2b856SArnaldo Carvalho de Melo __module_get(tw->tw_prot->owner); 204c676270bSArnaldo Carvalho de Melo } 205c676270bSArnaldo Carvalho de Melo 206c676270bSArnaldo Carvalho de Melo return tw; 207c676270bSArnaldo Carvalho de Melo } 208696ab2d3SArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(inet_twsk_alloc); 209696ab2d3SArnaldo Carvalho de Melo 210696ab2d3SArnaldo Carvalho de Melo /* These are always called from BH context. See callers in 211696ab2d3SArnaldo Carvalho de Melo * tcp_input.c to verify this. 212696ab2d3SArnaldo Carvalho de Melo */ 213696ab2d3SArnaldo Carvalho de Melo 214dbe7faa4SEric Dumazet /* This is for handling early-kills of TIME_WAIT sockets. 215dbe7faa4SEric Dumazet * Warning : consume reference. 216dbe7faa4SEric Dumazet * Caller should not access tw anymore. 217dbe7faa4SEric Dumazet */ 218dbe7faa4SEric Dumazet void inet_twsk_deschedule_put(struct inet_timewait_sock *tw) 219696ab2d3SArnaldo Carvalho de Melo { 220789f558cSEric Dumazet if (del_timer_sync(&tw->tw_timer)) 221789f558cSEric Dumazet inet_twsk_kill(tw); 222dbe7faa4SEric Dumazet inet_twsk_put(tw); 223696ab2d3SArnaldo Carvalho de Melo } 224dbe7faa4SEric Dumazet EXPORT_SYMBOL(inet_twsk_deschedule_put); 225696ab2d3SArnaldo Carvalho de Melo 226ed2e9239SEric Dumazet void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm) 227696ab2d3SArnaldo Carvalho de Melo { 228696ab2d3SArnaldo Carvalho de Melo /* timeout := RTO * 3.5 229696ab2d3SArnaldo Carvalho de Melo * 230696ab2d3SArnaldo Carvalho de Melo * 3.5 = 1+2+0.5 to wait for two retransmits. 231696ab2d3SArnaldo Carvalho de Melo * 232696ab2d3SArnaldo Carvalho de Melo * RATIONALE: if FIN arrived and we entered TIME-WAIT state, 233696ab2d3SArnaldo Carvalho de Melo * our ACK acking that FIN can be lost. If N subsequent retransmitted 234696ab2d3SArnaldo Carvalho de Melo * FINs (or previous seqments) are lost (probability of such event 235696ab2d3SArnaldo Carvalho de Melo * is p^(N+1), where p is probability to lose single packet and 236696ab2d3SArnaldo Carvalho de Melo * time to detect the loss is about RTO*(2^N - 1) with exponential 237696ab2d3SArnaldo Carvalho de Melo * backoff). Normal timewait length is calculated so, that we 238696ab2d3SArnaldo Carvalho de Melo * waited at least for one retransmitted FIN (maximal RTO is 120sec). 239696ab2d3SArnaldo Carvalho de Melo * [ BTW Linux. following BSD, violates this requirement waiting 240696ab2d3SArnaldo Carvalho de Melo * only for 60sec, we should wait at least for 240 secs. 241696ab2d3SArnaldo Carvalho de Melo * Well, 240 consumes too much of resources 8) 242696ab2d3SArnaldo Carvalho de Melo * ] 243696ab2d3SArnaldo Carvalho de Melo * This interval is not reduced to catch old duplicate and 244696ab2d3SArnaldo Carvalho de Melo * responces to our wandering segments living for two MSLs. 245696ab2d3SArnaldo Carvalho de Melo * However, if we use PAWS to detect 246696ab2d3SArnaldo Carvalho de Melo * old duplicates, we can reduce the interval to bounds required 247696ab2d3SArnaldo Carvalho de Melo * by RTO, rather than MSL. So, if peer understands PAWS, we 248696ab2d3SArnaldo Carvalho de Melo * kill tw bucket after 3.5*RTO (it is important that this number 249696ab2d3SArnaldo Carvalho de Melo * is greater than TS tick!) and detect old duplicates with help 250696ab2d3SArnaldo Carvalho de Melo * of PAWS. 251696ab2d3SArnaldo Carvalho de Melo */ 252696ab2d3SArnaldo Carvalho de Melo 253ed2e9239SEric Dumazet if (!rearm) { 25427dd35e0SEric Dumazet bool kill = timeo <= 4*HZ; 25527dd35e0SEric Dumazet 25627dd35e0SEric Dumazet __NET_INC_STATS(twsk_net(tw), kill ? LINUX_MIB_TIMEWAITKILLED : 25727dd35e0SEric Dumazet LINUX_MIB_TIMEWAITED); 258f3438bc7SThomas Gleixner BUG_ON(mod_timer(&tw->tw_timer, jiffies + timeo)); 259fbb82952SEric Dumazet refcount_inc(&tw->tw_dr->tw_refcount); 260ed2e9239SEric Dumazet } else { 261ed2e9239SEric Dumazet mod_timer_pending(&tw->tw_timer, jiffies + timeo); 262696ab2d3SArnaldo Carvalho de Melo } 263696ab2d3SArnaldo Carvalho de Melo } 264ed2e9239SEric Dumazet EXPORT_SYMBOL_GPL(__inet_twsk_schedule); 26504c494e6SEric Dumazet 26604c494e6SEric Dumazet void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family) 26704c494e6SEric Dumazet { 26804c494e6SEric Dumazet struct inet_timewait_sock *tw; 26904c494e6SEric Dumazet struct sock *sk; 27004c494e6SEric Dumazet struct hlist_nulls_node *node; 27104c494e6SEric Dumazet unsigned int slot; 27204c494e6SEric Dumazet 27304c494e6SEric Dumazet for (slot = 0; slot <= hashinfo->ehash_mask; slot++) { 27404c494e6SEric Dumazet struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 27504c494e6SEric Dumazet restart_rcu: 27604c494e6SEric Dumazet cond_resched(); 27704c494e6SEric Dumazet rcu_read_lock(); 27804c494e6SEric Dumazet restart: 27904c494e6SEric Dumazet sk_nulls_for_each_rcu(sk, node, &head->chain) { 280740ea3c4SKuniyuki Iwashima if (sk->sk_state != TCP_TIME_WAIT) { 281740ea3c4SKuniyuki Iwashima /* A kernel listener socket might not hold refcnt for net, 282740ea3c4SKuniyuki Iwashima * so reqsk_timer_handler() could be fired after net is 283740ea3c4SKuniyuki Iwashima * freed. Userspace listener and reqsk never exist here. 284740ea3c4SKuniyuki Iwashima */ 285740ea3c4SKuniyuki Iwashima if (unlikely(sk->sk_state == TCP_NEW_SYN_RECV && 286740ea3c4SKuniyuki Iwashima hashinfo->pernet)) { 287740ea3c4SKuniyuki Iwashima struct request_sock *req = inet_reqsk(sk); 288740ea3c4SKuniyuki Iwashima 289740ea3c4SKuniyuki Iwashima inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req); 290740ea3c4SKuniyuki Iwashima } 291740ea3c4SKuniyuki Iwashima 29204c494e6SEric Dumazet continue; 293740ea3c4SKuniyuki Iwashima } 294740ea3c4SKuniyuki Iwashima 29504c494e6SEric Dumazet tw = inet_twsk(sk); 29604c494e6SEric Dumazet if ((tw->tw_family != family) || 29704c494e6SEric Dumazet refcount_read(&twsk_net(tw)->ns.count)) 29804c494e6SEric Dumazet continue; 29904c494e6SEric Dumazet 30004c494e6SEric Dumazet if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt))) 30104c494e6SEric Dumazet continue; 30204c494e6SEric Dumazet 30304c494e6SEric Dumazet if (unlikely((tw->tw_family != family) || 30404c494e6SEric Dumazet refcount_read(&twsk_net(tw)->ns.count))) { 30504c494e6SEric Dumazet inet_twsk_put(tw); 30604c494e6SEric Dumazet goto restart; 30704c494e6SEric Dumazet } 30804c494e6SEric Dumazet 30904c494e6SEric Dumazet rcu_read_unlock(); 31004c494e6SEric Dumazet local_bh_disable(); 31104c494e6SEric Dumazet inet_twsk_deschedule_put(tw); 31204c494e6SEric Dumazet local_bh_enable(); 31304c494e6SEric Dumazet goto restart_rcu; 31404c494e6SEric Dumazet } 31504c494e6SEric Dumazet /* If the nulls value we got at the end of this lookup is 31604c494e6SEric Dumazet * not the expected one, we must restart lookup. 31704c494e6SEric Dumazet * We probably met an item that was moved to another chain. 31804c494e6SEric Dumazet */ 31904c494e6SEric Dumazet if (get_nulls_value(node) != slot) 32004c494e6SEric Dumazet goto restart; 32104c494e6SEric Dumazet rcu_read_unlock(); 32204c494e6SEric Dumazet } 32304c494e6SEric Dumazet } 32404c494e6SEric Dumazet EXPORT_SYMBOL_GPL(inet_twsk_purge); 325