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304a1618 ACM |
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 | * Authors: Lotsa people, from code originally in tcp | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; either version | |
11 | * 2 of the License, or (at your option) any later version. | |
12 | */ | |
13 | ||
14 | #ifndef _INET_HASHTABLES_H | |
15 | #define _INET_HASHTABLES_H | |
16 | ||
8feaf0c0 ACM |
17 | #include <linux/config.h> |
18 | ||
2d8c4ce5 | 19 | #include <linux/interrupt.h> |
33b62231 | 20 | #include <linux/ipv6.h> |
77d8bf9c ACM |
21 | #include <linux/list.h> |
22 | #include <linux/slab.h> | |
33b62231 | 23 | #include <linux/socket.h> |
77d8bf9c | 24 | #include <linux/spinlock.h> |
304a1618 | 25 | #include <linux/types.h> |
f3f05f70 | 26 | #include <linux/wait.h> |
304a1618 | 27 | |
463c84b9 | 28 | #include <net/inet_connection_sock.h> |
2d8c4ce5 | 29 | #include <net/sock.h> |
c752f073 | 30 | #include <net/tcp_states.h> |
2d8c4ce5 | 31 | |
f3f05f70 | 32 | #include <asm/atomic.h> |
e48c414e | 33 | #include <asm/byteorder.h> |
f3f05f70 | 34 | |
77d8bf9c ACM |
35 | /* This is for all connections with a full identity, no wildcards. |
36 | * New scheme, half the table is for TIME_WAIT, the other half is | |
37 | * for the rest. I'll experiment with dynamic table growth later. | |
38 | */ | |
39 | struct inet_ehash_bucket { | |
40 | rwlock_t lock; | |
41 | struct hlist_head chain; | |
42 | } __attribute__((__aligned__(8))); | |
43 | ||
44 | /* There are a few simple rules, which allow for local port reuse by | |
45 | * an application. In essence: | |
46 | * | |
47 | * 1) Sockets bound to different interfaces may share a local port. | |
48 | * Failing that, goto test 2. | |
49 | * 2) If all sockets have sk->sk_reuse set, and none of them are in | |
50 | * TCP_LISTEN state, the port may be shared. | |
51 | * Failing that, goto test 3. | |
52 | * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local | |
53 | * address, and none of them are the same, the port may be | |
54 | * shared. | |
55 | * Failing this, the port cannot be shared. | |
56 | * | |
57 | * The interesting point, is test #2. This is what an FTP server does | |
58 | * all day. To optimize this case we use a specific flag bit defined | |
59 | * below. As we add sockets to a bind bucket list, we perform a | |
60 | * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN)) | |
61 | * As long as all sockets added to a bind bucket pass this test, | |
62 | * the flag bit will be set. | |
63 | * The resulting situation is that tcp_v[46]_verify_bind() can just check | |
64 | * for this flag bit, if it is set and the socket trying to bind has | |
65 | * sk->sk_reuse set, we don't even have to walk the owners list at all, | |
66 | * we return that it is ok to bind this socket to the requested local port. | |
67 | * | |
68 | * Sounds like a lot of work, but it is worth it. In a more naive | |
69 | * implementation (ie. current FreeBSD etc.) the entire list of ports | |
70 | * must be walked for each data port opened by an ftp server. Needless | |
71 | * to say, this does not scale at all. With a couple thousand FTP | |
72 | * users logged onto your box, isn't it nice to know that new data | |
73 | * ports are created in O(1) time? I thought so. ;-) -DaveM | |
74 | */ | |
75 | struct inet_bind_bucket { | |
76 | unsigned short port; | |
77 | signed short fastreuse; | |
78 | struct hlist_node node; | |
79 | struct hlist_head owners; | |
80 | }; | |
81 | ||
82 | #define inet_bind_bucket_for_each(tb, node, head) \ | |
83 | hlist_for_each_entry(tb, node, head, node) | |
84 | ||
85 | struct inet_bind_hashbucket { | |
86 | spinlock_t lock; | |
87 | struct hlist_head chain; | |
88 | }; | |
89 | ||
90 | /* This is for listening sockets, thus all sockets which possess wildcards. */ | |
91 | #define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */ | |
92 | ||
93 | struct inet_hashinfo { | |
94 | /* This is for sockets with full identity only. Sockets here will | |
95 | * always be without wildcards and will have the following invariant: | |
96 | * | |
97 | * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE | |
98 | * | |
99 | * First half of the table is for sockets not in TIME_WAIT, second half | |
100 | * is for TIME_WAIT sockets only. | |
101 | */ | |
102 | struct inet_ehash_bucket *ehash; | |
103 | ||
104 | /* Ok, let's try this, I give up, we do need a local binding | |
105 | * TCP hash as well as the others for fast bind/connect. | |
106 | */ | |
107 | struct inet_bind_hashbucket *bhash; | |
108 | ||
109 | int bhash_size; | |
110 | int ehash_size; | |
111 | ||
112 | /* All sockets in TCP_LISTEN state will be in here. This is the only | |
113 | * table where wildcard'd TCP sockets can exist. Hash function here | |
114 | * is just local port number. | |
115 | */ | |
116 | struct hlist_head listening_hash[INET_LHTABLE_SIZE]; | |
117 | ||
118 | /* All the above members are written once at bootup and | |
119 | * never written again _or_ are predominantly read-access. | |
120 | * | |
121 | * Now align to a new cache line as all the following members | |
122 | * are often dirty. | |
123 | */ | |
124 | rwlock_t lhash_lock ____cacheline_aligned; | |
125 | atomic_t lhash_users; | |
126 | wait_queue_head_t lhash_wait; | |
127 | spinlock_t portalloc_lock; | |
2d8c4ce5 | 128 | kmem_cache_t *bind_bucket_cachep; |
6e04e021 | 129 | int port_rover; |
77d8bf9c ACM |
130 | }; |
131 | ||
304a1618 ACM |
132 | static inline int inet_ehashfn(const __u32 laddr, const __u16 lport, |
133 | const __u32 faddr, const __u16 fport, | |
134 | const int ehash_size) | |
135 | { | |
136 | int h = (laddr ^ lport) ^ (faddr ^ fport); | |
137 | h ^= h >> 16; | |
138 | h ^= h >> 8; | |
139 | return h & (ehash_size - 1); | |
140 | } | |
141 | ||
142 | static inline int inet_sk_ehashfn(const struct sock *sk, const int ehash_size) | |
143 | { | |
144 | const struct inet_sock *inet = inet_sk(sk); | |
145 | const __u32 laddr = inet->rcv_saddr; | |
146 | const __u16 lport = inet->num; | |
147 | const __u32 faddr = inet->daddr; | |
148 | const __u16 fport = inet->dport; | |
149 | ||
150 | return inet_ehashfn(laddr, lport, faddr, fport, ehash_size); | |
151 | } | |
152 | ||
77d8bf9c ACM |
153 | extern struct inet_bind_bucket * |
154 | inet_bind_bucket_create(kmem_cache_t *cachep, | |
155 | struct inet_bind_hashbucket *head, | |
156 | const unsigned short snum); | |
157 | extern void inet_bind_bucket_destroy(kmem_cache_t *cachep, | |
158 | struct inet_bind_bucket *tb); | |
159 | ||
160 | static inline int inet_bhashfn(const __u16 lport, const int bhash_size) | |
161 | { | |
162 | return lport & (bhash_size - 1); | |
163 | } | |
164 | ||
2d8c4ce5 ACM |
165 | extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, |
166 | const unsigned short snum); | |
167 | ||
77d8bf9c ACM |
168 | /* These can have wildcards, don't try too hard. */ |
169 | static inline int inet_lhashfn(const unsigned short num) | |
170 | { | |
171 | return num & (INET_LHTABLE_SIZE - 1); | |
172 | } | |
173 | ||
174 | static inline int inet_sk_listen_hashfn(const struct sock *sk) | |
175 | { | |
176 | return inet_lhashfn(inet_sk(sk)->num); | |
177 | } | |
178 | ||
2d8c4ce5 ACM |
179 | /* Caller must disable local BH processing. */ |
180 | static inline void __inet_inherit_port(struct inet_hashinfo *table, | |
181 | struct sock *sk, struct sock *child) | |
182 | { | |
183 | const int bhash = inet_bhashfn(inet_sk(child)->num, table->bhash_size); | |
184 | struct inet_bind_hashbucket *head = &table->bhash[bhash]; | |
185 | struct inet_bind_bucket *tb; | |
186 | ||
187 | spin_lock(&head->lock); | |
463c84b9 | 188 | tb = inet_csk(sk)->icsk_bind_hash; |
2d8c4ce5 | 189 | sk_add_bind_node(child, &tb->owners); |
463c84b9 | 190 | inet_csk(child)->icsk_bind_hash = tb; |
2d8c4ce5 ACM |
191 | spin_unlock(&head->lock); |
192 | } | |
193 | ||
194 | static inline void inet_inherit_port(struct inet_hashinfo *table, | |
195 | struct sock *sk, struct sock *child) | |
196 | { | |
197 | local_bh_disable(); | |
198 | __inet_inherit_port(table, sk, child); | |
199 | local_bh_enable(); | |
200 | } | |
201 | ||
202 | extern void inet_put_port(struct inet_hashinfo *table, struct sock *sk); | |
203 | ||
f3f05f70 ACM |
204 | extern void inet_listen_wlock(struct inet_hashinfo *hashinfo); |
205 | ||
206 | /* | |
207 | * - We may sleep inside this lock. | |
208 | * - If sleeping is not required (or called from BH), | |
209 | * use plain read_(un)lock(&inet_hashinfo.lhash_lock). | |
210 | */ | |
211 | static inline void inet_listen_lock(struct inet_hashinfo *hashinfo) | |
212 | { | |
213 | /* read_lock synchronizes to candidates to writers */ | |
214 | read_lock(&hashinfo->lhash_lock); | |
215 | atomic_inc(&hashinfo->lhash_users); | |
216 | read_unlock(&hashinfo->lhash_lock); | |
217 | } | |
218 | ||
219 | static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo) | |
220 | { | |
221 | if (atomic_dec_and_test(&hashinfo->lhash_users)) | |
222 | wake_up(&hashinfo->lhash_wait); | |
223 | } | |
224 | ||
225 | static inline void __inet_hash(struct inet_hashinfo *hashinfo, | |
226 | struct sock *sk, const int listen_possible) | |
227 | { | |
228 | struct hlist_head *list; | |
229 | rwlock_t *lock; | |
230 | ||
231 | BUG_TRAP(sk_unhashed(sk)); | |
232 | if (listen_possible && sk->sk_state == TCP_LISTEN) { | |
233 | list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; | |
234 | lock = &hashinfo->lhash_lock; | |
235 | inet_listen_wlock(hashinfo); | |
236 | } else { | |
237 | sk->sk_hashent = inet_sk_ehashfn(sk, hashinfo->ehash_size); | |
238 | list = &hashinfo->ehash[sk->sk_hashent].chain; | |
239 | lock = &hashinfo->ehash[sk->sk_hashent].lock; | |
240 | write_lock(lock); | |
241 | } | |
242 | __sk_add_node(sk, list); | |
243 | sock_prot_inc_use(sk->sk_prot); | |
244 | write_unlock(lock); | |
245 | if (listen_possible && sk->sk_state == TCP_LISTEN) | |
246 | wake_up(&hashinfo->lhash_wait); | |
247 | } | |
81849d10 ACM |
248 | |
249 | static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk) | |
250 | { | |
251 | if (sk->sk_state != TCP_CLOSE) { | |
252 | local_bh_disable(); | |
253 | __inet_hash(hashinfo, sk, 1); | |
254 | local_bh_enable(); | |
255 | } | |
256 | } | |
257 | ||
258 | static inline void inet_unhash(struct inet_hashinfo *hashinfo, struct sock *sk) | |
259 | { | |
260 | rwlock_t *lock; | |
261 | ||
262 | if (sk_unhashed(sk)) | |
263 | goto out; | |
264 | ||
265 | if (sk->sk_state == TCP_LISTEN) { | |
266 | local_bh_disable(); | |
267 | inet_listen_wlock(hashinfo); | |
268 | lock = &hashinfo->lhash_lock; | |
269 | } else { | |
270 | struct inet_ehash_bucket *head = &hashinfo->ehash[sk->sk_hashent]; | |
271 | lock = &head->lock; | |
272 | write_lock_bh(&head->lock); | |
273 | } | |
274 | ||
275 | if (__sk_del_node_init(sk)) | |
276 | sock_prot_dec_use(sk->sk_prot); | |
277 | write_unlock_bh(lock); | |
278 | out: | |
279 | if (sk->sk_state == TCP_LISTEN) | |
280 | wake_up(&hashinfo->lhash_wait); | |
281 | } | |
33b62231 ACM |
282 | |
283 | extern struct sock *__inet_lookup_listener(const struct hlist_head *head, | |
284 | const u32 daddr, | |
285 | const unsigned short hnum, | |
286 | const int dif); | |
287 | ||
288 | /* Optimize the common listener case. */ | |
e48c414e ACM |
289 | static inline struct sock * |
290 | inet_lookup_listener(struct inet_hashinfo *hashinfo, | |
291 | const u32 daddr, | |
292 | const unsigned short hnum, const int dif) | |
33b62231 ACM |
293 | { |
294 | struct sock *sk = NULL; | |
e48c414e | 295 | const struct hlist_head *head; |
33b62231 ACM |
296 | |
297 | read_lock(&hashinfo->lhash_lock); | |
298 | head = &hashinfo->listening_hash[inet_lhashfn(hnum)]; | |
299 | if (!hlist_empty(head)) { | |
300 | const struct inet_sock *inet = inet_sk((sk = __sk_head(head))); | |
301 | ||
302 | if (inet->num == hnum && !sk->sk_node.next && | |
303 | (!inet->rcv_saddr || inet->rcv_saddr == daddr) && | |
304 | (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) && | |
305 | !sk->sk_bound_dev_if) | |
306 | goto sherry_cache; | |
307 | sk = __inet_lookup_listener(head, daddr, hnum, dif); | |
308 | } | |
309 | if (sk) { | |
310 | sherry_cache: | |
311 | sock_hold(sk); | |
312 | } | |
313 | read_unlock(&hashinfo->lhash_lock); | |
314 | return sk; | |
315 | } | |
8feaf0c0 ACM |
316 | |
317 | /* Socket demux engine toys. */ | |
318 | #ifdef __BIG_ENDIAN | |
319 | #define INET_COMBINED_PORTS(__sport, __dport) \ | |
320 | (((__u32)(__sport) << 16) | (__u32)(__dport)) | |
321 | #else /* __LITTLE_ENDIAN */ | |
322 | #define INET_COMBINED_PORTS(__sport, __dport) \ | |
323 | (((__u32)(__dport) << 16) | (__u32)(__sport)) | |
324 | #endif | |
325 | ||
326 | #if (BITS_PER_LONG == 64) | |
327 | #ifdef __BIG_ENDIAN | |
328 | #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ | |
329 | const __u64 __name = (((__u64)(__saddr)) << 32) | ((__u64)(__daddr)); | |
330 | #else /* __LITTLE_ENDIAN */ | |
331 | #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ | |
332 | const __u64 __name = (((__u64)(__daddr)) << 32) | ((__u64)(__saddr)); | |
333 | #endif /* __BIG_ENDIAN */ | |
334 | #define INET_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ | |
335 | (((*((__u64 *)&(inet_sk(__sk)->daddr))) == (__cookie)) && \ | |
336 | ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \ | |
337 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
338 | #define INET_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ | |
339 | (((*((__u64 *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) && \ | |
340 | ((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ | |
341 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
342 | #else /* 32-bit arch */ | |
343 | #define INET_ADDR_COOKIE(__name, __saddr, __daddr) | |
344 | #define INET_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif) \ | |
345 | ((inet_sk(__sk)->daddr == (__saddr)) && \ | |
346 | (inet_sk(__sk)->rcv_saddr == (__daddr)) && \ | |
347 | ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \ | |
348 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
349 | #define INET_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif) \ | |
350 | ((inet_twsk(__sk)->tw_daddr == (__saddr)) && \ | |
351 | (inet_twsk(__sk)->tw_rcv_saddr == (__daddr)) && \ | |
352 | ((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ | |
353 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
354 | #endif /* 64-bit arch */ | |
e48c414e ACM |
355 | |
356 | /* | |
357 | * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need | |
358 | * not check it for lookups anymore, thanks Alexey. -DaveM | |
359 | * | |
360 | * Local BH must be disabled here. | |
361 | */ | |
362 | static inline struct sock * | |
363 | __inet_lookup_established(struct inet_hashinfo *hashinfo, | |
364 | const u32 saddr, const u16 sport, | |
365 | const u32 daddr, const u16 hnum, | |
366 | const int dif) | |
367 | { | |
368 | INET_ADDR_COOKIE(acookie, saddr, daddr) | |
369 | const __u32 ports = INET_COMBINED_PORTS(sport, hnum); | |
370 | struct sock *sk; | |
371 | const struct hlist_node *node; | |
372 | /* Optimize here for direct hit, only listening connections can | |
373 | * have wildcards anyways. | |
374 | */ | |
375 | const int hash = inet_ehashfn(daddr, hnum, saddr, sport, hashinfo->ehash_size); | |
376 | struct inet_ehash_bucket *head = &hashinfo->ehash[hash]; | |
377 | ||
378 | read_lock(&head->lock); | |
379 | sk_for_each(sk, node, &head->chain) { | |
380 | if (INET_MATCH(sk, acookie, saddr, daddr, ports, dif)) | |
381 | goto hit; /* You sunk my battleship! */ | |
382 | } | |
383 | ||
384 | /* Must check for a TIME_WAIT'er before going to listener hash. */ | |
385 | sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) { | |
386 | if (INET_TW_MATCH(sk, acookie, saddr, daddr, ports, dif)) | |
387 | goto hit; | |
388 | } | |
389 | sk = NULL; | |
390 | out: | |
391 | read_unlock(&head->lock); | |
392 | return sk; | |
393 | hit: | |
394 | sock_hold(sk); | |
395 | goto out; | |
396 | } | |
397 | ||
398 | static inline struct sock *__inet_lookup(struct inet_hashinfo *hashinfo, | |
399 | const u32 saddr, const u16 sport, | |
400 | const u32 daddr, const u16 hnum, | |
401 | const int dif) | |
402 | { | |
403 | struct sock *sk = __inet_lookup_established(hashinfo, saddr, sport, daddr, | |
404 | hnum, dif); | |
405 | return sk ? : inet_lookup_listener(hashinfo, daddr, hnum, dif); | |
406 | } | |
407 | ||
408 | static inline struct sock *inet_lookup(struct inet_hashinfo *hashinfo, | |
409 | const u32 saddr, const u16 sport, | |
410 | const u32 daddr, const u16 dport, | |
411 | const int dif) | |
412 | { | |
413 | struct sock *sk; | |
414 | ||
415 | local_bh_disable(); | |
416 | sk = __inet_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif); | |
417 | local_bh_enable(); | |
418 | ||
419 | return sk; | |
420 | } | |
304a1618 | 421 | #endif /* _INET_HASHTABLES_H */ |