xref: /openbmc/linux/include/net/inet_hashtables.h (revision 8897562f)
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  * Authors:	Lotsa people, from code originally in tcp
8  */
9 
10 #ifndef _INET_HASHTABLES_H
11 #define _INET_HASHTABLES_H
12 
13 
14 #include <linux/interrupt.h>
15 #include <linux/ip.h>
16 #include <linux/ipv6.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
19 #include <linux/socket.h>
20 #include <linux/spinlock.h>
21 #include <linux/types.h>
22 #include <linux/wait.h>
23 
24 #include <net/inet_connection_sock.h>
25 #include <net/inet_sock.h>
26 #include <net/ip.h>
27 #include <net/sock.h>
28 #include <net/route.h>
29 #include <net/tcp_states.h>
30 #include <net/netns/hash.h>
31 
32 #include <linux/refcount.h>
33 #include <asm/byteorder.h>
34 
35 /* This is for all connections with a full identity, no wildcards.
36  * The 'e' prefix stands for Establish, but we really put all sockets
37  * but LISTEN ones.
38  */
39 struct inet_ehash_bucket {
40 	struct hlist_nulls_head chain;
41 };
42 
43 /* There are a few simple rules, which allow for local port reuse by
44  * an application.  In essence:
45  *
46  *	1) Sockets bound to different interfaces may share a local port.
47  *	   Failing that, goto test 2.
48  *	2) If all sockets have sk->sk_reuse set, and none of them are in
49  *	   TCP_LISTEN state, the port may be shared.
50  *	   Failing that, goto test 3.
51  *	3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
52  *	   address, and none of them are the same, the port may be
53  *	   shared.
54  *	   Failing this, the port cannot be shared.
55  *
56  * The interesting point, is test #2.  This is what an FTP server does
57  * all day.  To optimize this case we use a specific flag bit defined
58  * below.  As we add sockets to a bind bucket list, we perform a
59  * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
60  * As long as all sockets added to a bind bucket pass this test,
61  * the flag bit will be set.
62  * The resulting situation is that tcp_v[46]_verify_bind() can just check
63  * for this flag bit, if it is set and the socket trying to bind has
64  * sk->sk_reuse set, we don't even have to walk the owners list at all,
65  * we return that it is ok to bind this socket to the requested local port.
66  *
67  * Sounds like a lot of work, but it is worth it.  In a more naive
68  * implementation (ie. current FreeBSD etc.) the entire list of ports
69  * must be walked for each data port opened by an ftp server.  Needless
70  * to say, this does not scale at all.  With a couple thousand FTP
71  * users logged onto your box, isn't it nice to know that new data
72  * ports are created in O(1) time?  I thought so. ;-)	-DaveM
73  */
74 #define FASTREUSEPORT_ANY	1
75 #define FASTREUSEPORT_STRICT	2
76 
77 struct inet_bind_bucket {
78 	possible_net_t		ib_net;
79 	int			l3mdev;
80 	unsigned short		port;
81 	signed char		fastreuse;
82 	signed char		fastreuseport;
83 	kuid_t			fastuid;
84 #if IS_ENABLED(CONFIG_IPV6)
85 	struct in6_addr		fast_v6_rcv_saddr;
86 #endif
87 	__be32			fast_rcv_saddr;
88 	unsigned short		fast_sk_family;
89 	bool			fast_ipv6_only;
90 	struct hlist_node	node;
91 	struct hlist_head	owners;
92 };
93 
94 struct inet_bind2_bucket {
95 	possible_net_t		ib_net;
96 	int			l3mdev;
97 	unsigned short		port;
98 #if IS_ENABLED(CONFIG_IPV6)
99 	unsigned short		family;
100 #endif
101 	union {
102 #if IS_ENABLED(CONFIG_IPV6)
103 		struct in6_addr		v6_rcv_saddr;
104 #endif
105 		__be32			rcv_saddr;
106 	};
107 	/* Node in the bhash2 inet_bind_hashbucket chain */
108 	struct hlist_node	node;
109 	/* List of sockets hashed to this bucket */
110 	struct hlist_head	owners;
111 	/* bhash has twsk in owners, but bhash2 has twsk in
112 	 * deathrow not to add a member in struct sock_common.
113 	 */
114 	struct hlist_head	deathrow;
115 };
116 
ib_net(const struct inet_bind_bucket * ib)117 static inline struct net *ib_net(const struct inet_bind_bucket *ib)
118 {
119 	return read_pnet(&ib->ib_net);
120 }
121 
ib2_net(const struct inet_bind2_bucket * ib)122 static inline struct net *ib2_net(const struct inet_bind2_bucket *ib)
123 {
124 	return read_pnet(&ib->ib_net);
125 }
126 
127 #define inet_bind_bucket_for_each(tb, head) \
128 	hlist_for_each_entry(tb, head, node)
129 
130 struct inet_bind_hashbucket {
131 	spinlock_t		lock;
132 	struct hlist_head	chain;
133 };
134 
135 /* Sockets can be hashed in established or listening table.
136  * We must use different 'nulls' end-of-chain value for all hash buckets :
137  * A socket might transition from ESTABLISH to LISTEN state without
138  * RCU grace period. A lookup in ehash table needs to handle this case.
139  */
140 #define LISTENING_NULLS_BASE (1U << 29)
141 struct inet_listen_hashbucket {
142 	spinlock_t		lock;
143 	struct hlist_nulls_head	nulls_head;
144 };
145 
146 /* This is for listening sockets, thus all sockets which possess wildcards. */
147 #define INET_LHTABLE_SIZE	32	/* Yes, really, this is all you need. */
148 
149 struct inet_hashinfo {
150 	/* This is for sockets with full identity only.  Sockets here will
151 	 * always be without wildcards and will have the following invariant:
152 	 *
153 	 *          TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
154 	 *
155 	 */
156 	struct inet_ehash_bucket	*ehash;
157 	spinlock_t			*ehash_locks;
158 	unsigned int			ehash_mask;
159 	unsigned int			ehash_locks_mask;
160 
161 	/* Ok, let's try this, I give up, we do need a local binding
162 	 * TCP hash as well as the others for fast bind/connect.
163 	 */
164 	struct kmem_cache		*bind_bucket_cachep;
165 	/* This bind table is hashed by local port */
166 	struct inet_bind_hashbucket	*bhash;
167 	struct kmem_cache		*bind2_bucket_cachep;
168 	/* This bind table is hashed by local port and sk->sk_rcv_saddr (ipv4)
169 	 * or sk->sk_v6_rcv_saddr (ipv6). This 2nd bind table is used
170 	 * primarily for expediting bind conflict resolution.
171 	 */
172 	struct inet_bind_hashbucket	*bhash2;
173 	unsigned int			bhash_size;
174 
175 	/* The 2nd listener table hashed by local port and address */
176 	unsigned int			lhash2_mask;
177 	struct inet_listen_hashbucket	*lhash2;
178 
179 	bool				pernet;
180 } ____cacheline_aligned_in_smp;
181 
tcp_or_dccp_get_hashinfo(const struct sock * sk)182 static inline struct inet_hashinfo *tcp_or_dccp_get_hashinfo(const struct sock *sk)
183 {
184 #if IS_ENABLED(CONFIG_IP_DCCP)
185 	return sk->sk_prot->h.hashinfo ? :
186 		sock_net(sk)->ipv4.tcp_death_row.hashinfo;
187 #else
188 	return sock_net(sk)->ipv4.tcp_death_row.hashinfo;
189 #endif
190 }
191 
192 static inline struct inet_listen_hashbucket *
inet_lhash2_bucket(struct inet_hashinfo * h,u32 hash)193 inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash)
194 {
195 	return &h->lhash2[hash & h->lhash2_mask];
196 }
197 
inet_ehash_bucket(struct inet_hashinfo * hashinfo,unsigned int hash)198 static inline struct inet_ehash_bucket *inet_ehash_bucket(
199 	struct inet_hashinfo *hashinfo,
200 	unsigned int hash)
201 {
202 	return &hashinfo->ehash[hash & hashinfo->ehash_mask];
203 }
204 
inet_ehash_lockp(struct inet_hashinfo * hashinfo,unsigned int hash)205 static inline spinlock_t *inet_ehash_lockp(
206 	struct inet_hashinfo *hashinfo,
207 	unsigned int hash)
208 {
209 	return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask];
210 }
211 
212 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo);
213 
inet_hashinfo2_free_mod(struct inet_hashinfo * h)214 static inline void inet_hashinfo2_free_mod(struct inet_hashinfo *h)
215 {
216 	kfree(h->lhash2);
217 	h->lhash2 = NULL;
218 }
219 
inet_ehash_locks_free(struct inet_hashinfo * hashinfo)220 static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
221 {
222 	kvfree(hashinfo->ehash_locks);
223 	hashinfo->ehash_locks = NULL;
224 }
225 
226 struct inet_hashinfo *inet_pernet_hashinfo_alloc(struct inet_hashinfo *hashinfo,
227 						 unsigned int ehash_entries);
228 void inet_pernet_hashinfo_free(struct inet_hashinfo *hashinfo);
229 
230 struct inet_bind_bucket *
231 inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net,
232 			struct inet_bind_hashbucket *head,
233 			const unsigned short snum, int l3mdev);
234 void inet_bind_bucket_destroy(struct kmem_cache *cachep,
235 			      struct inet_bind_bucket *tb);
236 
237 bool inet_bind_bucket_match(const struct inet_bind_bucket *tb,
238 			    const struct net *net, unsigned short port,
239 			    int l3mdev);
240 
241 struct inet_bind2_bucket *
242 inet_bind2_bucket_create(struct kmem_cache *cachep, struct net *net,
243 			 struct inet_bind_hashbucket *head,
244 			 unsigned short port, int l3mdev,
245 			 const struct sock *sk);
246 
247 void inet_bind2_bucket_destroy(struct kmem_cache *cachep,
248 			       struct inet_bind2_bucket *tb);
249 
250 struct inet_bind2_bucket *
251 inet_bind2_bucket_find(const struct inet_bind_hashbucket *head,
252 		       const struct net *net,
253 		       unsigned short port, int l3mdev,
254 		       const struct sock *sk);
255 
256 bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb,
257 				      const struct net *net, unsigned short port,
258 				      int l3mdev, const struct sock *sk);
259 
inet_bhashfn(const struct net * net,const __u16 lport,const u32 bhash_size)260 static inline u32 inet_bhashfn(const struct net *net, const __u16 lport,
261 			       const u32 bhash_size)
262 {
263 	return (lport + net_hash_mix(net)) & (bhash_size - 1);
264 }
265 
266 static inline struct inet_bind_hashbucket *
inet_bhashfn_portaddr(const struct inet_hashinfo * hinfo,const struct sock * sk,const struct net * net,unsigned short port)267 inet_bhashfn_portaddr(const struct inet_hashinfo *hinfo, const struct sock *sk,
268 		      const struct net *net, unsigned short port)
269 {
270 	u32 hash;
271 
272 #if IS_ENABLED(CONFIG_IPV6)
273 	if (sk->sk_family == AF_INET6)
274 		hash = ipv6_portaddr_hash(net, &sk->sk_v6_rcv_saddr, port);
275 	else
276 #endif
277 		hash = ipv4_portaddr_hash(net, sk->sk_rcv_saddr, port);
278 	return &hinfo->bhash2[hash & (hinfo->bhash_size - 1)];
279 }
280 
281 struct inet_bind_hashbucket *
282 inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, int port);
283 
284 /* This should be called whenever a socket's sk_rcv_saddr (ipv4) or
285  * sk_v6_rcv_saddr (ipv6) changes after it has been binded. The socket's
286  * rcv_saddr field should already have been updated when this is called.
287  */
288 int inet_bhash2_update_saddr(struct sock *sk, void *saddr, int family);
289 void inet_bhash2_reset_saddr(struct sock *sk);
290 
291 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
292 		    struct inet_bind2_bucket *tb2, unsigned short port);
293 
294 /* Caller must disable local BH processing. */
295 int __inet_inherit_port(const struct sock *sk, struct sock *child);
296 
297 void inet_put_port(struct sock *sk);
298 
299 void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
300 			 unsigned long numentries, int scale,
301 			 unsigned long low_limit,
302 			 unsigned long high_limit);
303 int inet_hashinfo2_init_mod(struct inet_hashinfo *h);
304 
305 bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk);
306 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk,
307 			 bool *found_dup_sk);
308 int __inet_hash(struct sock *sk, struct sock *osk);
309 int inet_hash(struct sock *sk);
310 void inet_unhash(struct sock *sk);
311 
312 struct sock *__inet_lookup_listener(struct net *net,
313 				    struct inet_hashinfo *hashinfo,
314 				    struct sk_buff *skb, int doff,
315 				    const __be32 saddr, const __be16 sport,
316 				    const __be32 daddr,
317 				    const unsigned short hnum,
318 				    const int dif, const int sdif);
319 
inet_lookup_listener(struct net * net,struct inet_hashinfo * hashinfo,struct sk_buff * skb,int doff,__be32 saddr,__be16 sport,__be32 daddr,__be16 dport,int dif,int sdif)320 static inline struct sock *inet_lookup_listener(struct net *net,
321 		struct inet_hashinfo *hashinfo,
322 		struct sk_buff *skb, int doff,
323 		__be32 saddr, __be16 sport,
324 		__be32 daddr, __be16 dport, int dif, int sdif)
325 {
326 	return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
327 				      daddr, ntohs(dport), dif, sdif);
328 }
329 
330 /* Socket demux engine toys. */
331 /* What happens here is ugly; there's a pair of adjacent fields in
332    struct inet_sock; __be16 dport followed by __u16 num.  We want to
333    search by pair, so we combine the keys into a single 32bit value
334    and compare with 32bit value read from &...->dport.  Let's at least
335    make sure that it's not mixed with anything else...
336    On 64bit targets we combine comparisons with pair of adjacent __be32
337    fields in the same way.
338 */
339 #ifdef __BIG_ENDIAN
340 #define INET_COMBINED_PORTS(__sport, __dport) \
341 	((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport)))
342 #else /* __LITTLE_ENDIAN */
343 #define INET_COMBINED_PORTS(__sport, __dport) \
344 	((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport)))
345 #endif
346 
347 #ifdef __BIG_ENDIAN
348 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
349 	const __addrpair __name = (__force __addrpair) ( \
350 				   (((__force __u64)(__be32)(__saddr)) << 32) | \
351 				   ((__force __u64)(__be32)(__daddr)))
352 #else /* __LITTLE_ENDIAN */
353 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
354 	const __addrpair __name = (__force __addrpair) ( \
355 				   (((__force __u64)(__be32)(__daddr)) << 32) | \
356 				   ((__force __u64)(__be32)(__saddr)))
357 #endif /* __BIG_ENDIAN */
358 
inet_match(struct net * net,const struct sock * sk,const __addrpair cookie,const __portpair ports,int dif,int sdif)359 static inline bool inet_match(struct net *net, const struct sock *sk,
360 			      const __addrpair cookie, const __portpair ports,
361 			      int dif, int sdif)
362 {
363 	if (!net_eq(sock_net(sk), net) ||
364 	    sk->sk_portpair != ports ||
365 	    sk->sk_addrpair != cookie)
366 	        return false;
367 
368 	/* READ_ONCE() paired with WRITE_ONCE() in sock_bindtoindex_locked() */
369 	return inet_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif,
370 				    sdif);
371 }
372 
373 /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
374  * not check it for lookups anymore, thanks Alexey. -DaveM
375  */
376 struct sock *__inet_lookup_established(struct net *net,
377 				       struct inet_hashinfo *hashinfo,
378 				       const __be32 saddr, const __be16 sport,
379 				       const __be32 daddr, const u16 hnum,
380 				       const int dif, const int sdif);
381 
382 typedef u32 (inet_ehashfn_t)(const struct net *net,
383 			      const __be32 laddr, const __u16 lport,
384 			      const __be32 faddr, const __be16 fport);
385 
386 inet_ehashfn_t inet_ehashfn;
387 
388 INDIRECT_CALLABLE_DECLARE(inet_ehashfn_t udp_ehashfn);
389 
390 struct sock *inet_lookup_reuseport(struct net *net, struct sock *sk,
391 				   struct sk_buff *skb, int doff,
392 				   __be32 saddr, __be16 sport,
393 				   __be32 daddr, unsigned short hnum,
394 				   inet_ehashfn_t *ehashfn);
395 
396 struct sock *inet_lookup_run_sk_lookup(struct net *net,
397 				       int protocol,
398 				       struct sk_buff *skb, int doff,
399 				       __be32 saddr, __be16 sport,
400 				       __be32 daddr, u16 hnum, const int dif,
401 				       inet_ehashfn_t *ehashfn);
402 
403 static inline struct sock *
inet_lookup_established(struct net * net,struct inet_hashinfo * hashinfo,const __be32 saddr,const __be16 sport,const __be32 daddr,const __be16 dport,const int dif)404 	inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo,
405 				const __be32 saddr, const __be16 sport,
406 				const __be32 daddr, const __be16 dport,
407 				const int dif)
408 {
409 	return __inet_lookup_established(net, hashinfo, saddr, sport, daddr,
410 					 ntohs(dport), dif, 0);
411 }
412 
__inet_lookup(struct net * net,struct inet_hashinfo * hashinfo,struct sk_buff * skb,int doff,const __be32 saddr,const __be16 sport,const __be32 daddr,const __be16 dport,const int dif,const int sdif,bool * refcounted)413 static inline struct sock *__inet_lookup(struct net *net,
414 					 struct inet_hashinfo *hashinfo,
415 					 struct sk_buff *skb, int doff,
416 					 const __be32 saddr, const __be16 sport,
417 					 const __be32 daddr, const __be16 dport,
418 					 const int dif, const int sdif,
419 					 bool *refcounted)
420 {
421 	u16 hnum = ntohs(dport);
422 	struct sock *sk;
423 
424 	sk = __inet_lookup_established(net, hashinfo, saddr, sport,
425 				       daddr, hnum, dif, sdif);
426 	*refcounted = true;
427 	if (sk)
428 		return sk;
429 	*refcounted = false;
430 	return __inet_lookup_listener(net, hashinfo, skb, doff, saddr,
431 				      sport, daddr, hnum, dif, sdif);
432 }
433 
inet_lookup(struct net * net,struct inet_hashinfo * hashinfo,struct sk_buff * skb,int doff,const __be32 saddr,const __be16 sport,const __be32 daddr,const __be16 dport,const int dif)434 static inline struct sock *inet_lookup(struct net *net,
435 				       struct inet_hashinfo *hashinfo,
436 				       struct sk_buff *skb, int doff,
437 				       const __be32 saddr, const __be16 sport,
438 				       const __be32 daddr, const __be16 dport,
439 				       const int dif)
440 {
441 	struct sock *sk;
442 	bool refcounted;
443 
444 	sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
445 			   dport, dif, 0, &refcounted);
446 
447 	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
448 		sk = NULL;
449 	return sk;
450 }
451 
452 static inline
inet_steal_sock(struct net * net,struct sk_buff * skb,int doff,const __be32 saddr,const __be16 sport,const __be32 daddr,const __be16 dport,bool * refcounted,inet_ehashfn_t * ehashfn)453 struct sock *inet_steal_sock(struct net *net, struct sk_buff *skb, int doff,
454 			     const __be32 saddr, const __be16 sport,
455 			     const __be32 daddr, const __be16 dport,
456 			     bool *refcounted, inet_ehashfn_t *ehashfn)
457 {
458 	struct sock *sk, *reuse_sk;
459 	bool prefetched;
460 
461 	sk = skb_steal_sock(skb, refcounted, &prefetched);
462 	if (!sk)
463 		return NULL;
464 
465 	if (!prefetched || !sk_fullsock(sk))
466 		return sk;
467 
468 	if (sk->sk_protocol == IPPROTO_TCP) {
469 		if (sk->sk_state != TCP_LISTEN)
470 			return sk;
471 	} else if (sk->sk_protocol == IPPROTO_UDP) {
472 		if (sk->sk_state != TCP_CLOSE)
473 			return sk;
474 	} else {
475 		return sk;
476 	}
477 
478 	reuse_sk = inet_lookup_reuseport(net, sk, skb, doff,
479 					 saddr, sport, daddr, ntohs(dport),
480 					 ehashfn);
481 	if (!reuse_sk)
482 		return sk;
483 
484 	/* We've chosen a new reuseport sock which is never refcounted. This
485 	 * implies that sk also isn't refcounted.
486 	 */
487 	WARN_ON_ONCE(*refcounted);
488 
489 	return reuse_sk;
490 }
491 
__inet_lookup_skb(struct inet_hashinfo * hashinfo,struct sk_buff * skb,int doff,const __be16 sport,const __be16 dport,const int sdif,bool * refcounted)492 static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
493 					     struct sk_buff *skb,
494 					     int doff,
495 					     const __be16 sport,
496 					     const __be16 dport,
497 					     const int sdif,
498 					     bool *refcounted)
499 {
500 	struct net *net = dev_net(skb_dst(skb)->dev);
501 	const struct iphdr *iph = ip_hdr(skb);
502 	struct sock *sk;
503 
504 	sk = inet_steal_sock(net, skb, doff, iph->saddr, sport, iph->daddr, dport,
505 			     refcounted, inet_ehashfn);
506 	if (IS_ERR(sk))
507 		return NULL;
508 	if (sk)
509 		return sk;
510 
511 	return __inet_lookup(net, hashinfo, skb,
512 			     doff, iph->saddr, sport,
513 			     iph->daddr, dport, inet_iif(skb), sdif,
514 			     refcounted);
515 }
516 
sk_daddr_set(struct sock * sk,__be32 addr)517 static inline void sk_daddr_set(struct sock *sk, __be32 addr)
518 {
519 	sk->sk_daddr = addr; /* alias of inet_daddr */
520 #if IS_ENABLED(CONFIG_IPV6)
521 	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr);
522 #endif
523 }
524 
sk_rcv_saddr_set(struct sock * sk,__be32 addr)525 static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
526 {
527 	sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */
528 #if IS_ENABLED(CONFIG_IPV6)
529 	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr);
530 #endif
531 }
532 
533 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
534 			struct sock *sk, u64 port_offset,
535 			int (*check_established)(struct inet_timewait_death_row *,
536 						 struct sock *, __u16,
537 						 struct inet_timewait_sock **));
538 
539 int inet_hash_connect(struct inet_timewait_death_row *death_row,
540 		      struct sock *sk);
541 #endif /* _INET_HASHTABLES_H */
542