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77d8bf9c 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 | * Generic INET transport hashtables | |
7 | * | |
8 | * Authors: Lotsa people, from code originally in tcp | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the License, or (at your option) any later version. | |
14 | */ | |
15 | ||
2d8c4ce5 | 16 | #include <linux/module.h> |
a7f5e7f1 | 17 | #include <linux/random.h> |
f3f05f70 | 18 | #include <linux/sched.h> |
77d8bf9c | 19 | #include <linux/slab.h> |
f3f05f70 | 20 | #include <linux/wait.h> |
77d8bf9c | 21 | |
463c84b9 | 22 | #include <net/inet_connection_sock.h> |
77d8bf9c | 23 | #include <net/inet_hashtables.h> |
a7f5e7f1 | 24 | #include <net/ip.h> |
77d8bf9c ACM |
25 | |
26 | /* | |
27 | * Allocate and initialize a new local port bind bucket. | |
28 | * The bindhash mutex for snum's hash chain must be held here. | |
29 | */ | |
30 | struct inet_bind_bucket *inet_bind_bucket_create(kmem_cache_t *cachep, | |
31 | struct inet_bind_hashbucket *head, | |
32 | const unsigned short snum) | |
33 | { | |
34 | struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, SLAB_ATOMIC); | |
35 | ||
36 | if (tb != NULL) { | |
37 | tb->port = snum; | |
38 | tb->fastreuse = 0; | |
39 | INIT_HLIST_HEAD(&tb->owners); | |
40 | hlist_add_head(&tb->node, &head->chain); | |
41 | } | |
42 | return tb; | |
43 | } | |
44 | ||
77d8bf9c ACM |
45 | /* |
46 | * Caller must hold hashbucket lock for this tb with local BH disabled | |
47 | */ | |
48 | void inet_bind_bucket_destroy(kmem_cache_t *cachep, struct inet_bind_bucket *tb) | |
49 | { | |
50 | if (hlist_empty(&tb->owners)) { | |
51 | __hlist_del(&tb->node); | |
52 | kmem_cache_free(cachep, tb); | |
53 | } | |
54 | } | |
2d8c4ce5 ACM |
55 | |
56 | void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, | |
57 | const unsigned short snum) | |
58 | { | |
463c84b9 | 59 | inet_sk(sk)->num = snum; |
2d8c4ce5 | 60 | sk_add_bind_node(sk, &tb->owners); |
463c84b9 | 61 | inet_csk(sk)->icsk_bind_hash = tb; |
2d8c4ce5 ACM |
62 | } |
63 | ||
2d8c4ce5 ACM |
64 | /* |
65 | * Get rid of any references to a local port held by the given sock. | |
66 | */ | |
67 | static void __inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) | |
68 | { | |
463c84b9 | 69 | const int bhash = inet_bhashfn(inet_sk(sk)->num, hashinfo->bhash_size); |
2d8c4ce5 ACM |
70 | struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash]; |
71 | struct inet_bind_bucket *tb; | |
72 | ||
73 | spin_lock(&head->lock); | |
463c84b9 | 74 | tb = inet_csk(sk)->icsk_bind_hash; |
2d8c4ce5 | 75 | __sk_del_bind_node(sk); |
463c84b9 ACM |
76 | inet_csk(sk)->icsk_bind_hash = NULL; |
77 | inet_sk(sk)->num = 0; | |
2d8c4ce5 ACM |
78 | inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); |
79 | spin_unlock(&head->lock); | |
80 | } | |
81 | ||
82 | void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) | |
83 | { | |
84 | local_bh_disable(); | |
85 | __inet_put_port(hashinfo, sk); | |
86 | local_bh_enable(); | |
87 | } | |
88 | ||
89 | EXPORT_SYMBOL(inet_put_port); | |
f3f05f70 ACM |
90 | |
91 | /* | |
92 | * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP. | |
93 | * Look, when several writers sleep and reader wakes them up, all but one | |
94 | * immediately hit write lock and grab all the cpus. Exclusive sleep solves | |
95 | * this, _but_ remember, it adds useless work on UP machines (wake up each | |
96 | * exclusive lock release). It should be ifdefed really. | |
97 | */ | |
98 | void inet_listen_wlock(struct inet_hashinfo *hashinfo) | |
99 | { | |
100 | write_lock(&hashinfo->lhash_lock); | |
101 | ||
102 | if (atomic_read(&hashinfo->lhash_users)) { | |
103 | DEFINE_WAIT(wait); | |
104 | ||
105 | for (;;) { | |
106 | prepare_to_wait_exclusive(&hashinfo->lhash_wait, | |
107 | &wait, TASK_UNINTERRUPTIBLE); | |
108 | if (!atomic_read(&hashinfo->lhash_users)) | |
109 | break; | |
110 | write_unlock_bh(&hashinfo->lhash_lock); | |
111 | schedule(); | |
112 | write_lock_bh(&hashinfo->lhash_lock); | |
113 | } | |
114 | ||
115 | finish_wait(&hashinfo->lhash_wait, &wait); | |
116 | } | |
117 | } | |
118 | ||
119 | EXPORT_SYMBOL(inet_listen_wlock); | |
33b62231 ACM |
120 | |
121 | /* | |
122 | * Don't inline this cruft. Here are some nice properties to exploit here. The | |
123 | * BSD API does not allow a listening sock to specify the remote port nor the | |
124 | * remote address for the connection. So always assume those are both | |
125 | * wildcarded during the search since they can never be otherwise. | |
126 | */ | |
127 | struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 daddr, | |
128 | const unsigned short hnum, const int dif) | |
129 | { | |
130 | struct sock *result = NULL, *sk; | |
131 | const struct hlist_node *node; | |
132 | int hiscore = -1; | |
133 | ||
134 | sk_for_each(sk, node, head) { | |
135 | const struct inet_sock *inet = inet_sk(sk); | |
136 | ||
137 | if (inet->num == hnum && !ipv6_only_sock(sk)) { | |
138 | const __u32 rcv_saddr = inet->rcv_saddr; | |
139 | int score = sk->sk_family == PF_INET ? 1 : 0; | |
140 | ||
141 | if (rcv_saddr) { | |
142 | if (rcv_saddr != daddr) | |
143 | continue; | |
144 | score += 2; | |
145 | } | |
146 | if (sk->sk_bound_dev_if) { | |
147 | if (sk->sk_bound_dev_if != dif) | |
148 | continue; | |
149 | score += 2; | |
150 | } | |
151 | if (score == 5) | |
152 | return sk; | |
153 | if (score > hiscore) { | |
154 | hiscore = score; | |
155 | result = sk; | |
156 | } | |
157 | } | |
158 | } | |
159 | return result; | |
160 | } | |
e48c414e ACM |
161 | |
162 | EXPORT_SYMBOL_GPL(__inet_lookup_listener); | |
a7f5e7f1 ACM |
163 | |
164 | /* called with local bh disabled */ | |
165 | static int __inet_check_established(struct inet_timewait_death_row *death_row, | |
166 | struct sock *sk, __u16 lport, | |
167 | struct inet_timewait_sock **twp) | |
168 | { | |
169 | struct inet_hashinfo *hinfo = death_row->hashinfo; | |
170 | struct inet_sock *inet = inet_sk(sk); | |
171 | u32 daddr = inet->rcv_saddr; | |
172 | u32 saddr = inet->daddr; | |
173 | int dif = sk->sk_bound_dev_if; | |
174 | INET_ADDR_COOKIE(acookie, saddr, daddr) | |
175 | const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport); | |
176 | unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport); | |
177 | struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); | |
178 | struct sock *sk2; | |
179 | const struct hlist_node *node; | |
180 | struct inet_timewait_sock *tw; | |
181 | ||
182 | prefetch(head->chain.first); | |
183 | write_lock(&head->lock); | |
184 | ||
185 | /* Check TIME-WAIT sockets first. */ | |
186 | sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) { | |
187 | tw = inet_twsk(sk2); | |
188 | ||
189 | if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) { | |
190 | if (twsk_unique(sk, sk2, twp)) | |
191 | goto unique; | |
192 | else | |
193 | goto not_unique; | |
194 | } | |
195 | } | |
196 | tw = NULL; | |
197 | ||
198 | /* And established part... */ | |
199 | sk_for_each(sk2, node, &head->chain) { | |
200 | if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) | |
201 | goto not_unique; | |
202 | } | |
203 | ||
204 | unique: | |
205 | /* Must record num and sport now. Otherwise we will see | |
206 | * in hash table socket with a funny identity. */ | |
207 | inet->num = lport; | |
208 | inet->sport = htons(lport); | |
209 | sk->sk_hash = hash; | |
210 | BUG_TRAP(sk_unhashed(sk)); | |
211 | __sk_add_node(sk, &head->chain); | |
212 | sock_prot_inc_use(sk->sk_prot); | |
213 | write_unlock(&head->lock); | |
214 | ||
215 | if (twp) { | |
216 | *twp = tw; | |
217 | NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); | |
218 | } else if (tw) { | |
219 | /* Silly. Should hash-dance instead... */ | |
220 | inet_twsk_deschedule(tw, death_row); | |
221 | NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); | |
222 | ||
223 | inet_twsk_put(tw); | |
224 | } | |
225 | ||
226 | return 0; | |
227 | ||
228 | not_unique: | |
229 | write_unlock(&head->lock); | |
230 | return -EADDRNOTAVAIL; | |
231 | } | |
232 | ||
233 | static inline u32 inet_sk_port_offset(const struct sock *sk) | |
234 | { | |
235 | const struct inet_sock *inet = inet_sk(sk); | |
236 | return secure_ipv4_port_ephemeral(inet->rcv_saddr, inet->daddr, | |
237 | inet->dport); | |
238 | } | |
239 | ||
240 | /* | |
241 | * Bind a port for a connect operation and hash it. | |
242 | */ | |
243 | int inet_hash_connect(struct inet_timewait_death_row *death_row, | |
244 | struct sock *sk) | |
245 | { | |
246 | struct inet_hashinfo *hinfo = death_row->hashinfo; | |
247 | const unsigned short snum = inet_sk(sk)->num; | |
248 | struct inet_bind_hashbucket *head; | |
249 | struct inet_bind_bucket *tb; | |
250 | int ret; | |
251 | ||
252 | if (!snum) { | |
253 | int low = sysctl_local_port_range[0]; | |
254 | int high = sysctl_local_port_range[1]; | |
255 | int range = high - low; | |
256 | int i; | |
257 | int port; | |
258 | static u32 hint; | |
259 | u32 offset = hint + inet_sk_port_offset(sk); | |
260 | struct hlist_node *node; | |
261 | struct inet_timewait_sock *tw = NULL; | |
262 | ||
263 | local_bh_disable(); | |
264 | for (i = 1; i <= range; i++) { | |
265 | port = low + (i + offset) % range; | |
266 | head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)]; | |
267 | spin_lock(&head->lock); | |
268 | ||
269 | /* Does not bother with rcv_saddr checks, | |
270 | * because the established check is already | |
271 | * unique enough. | |
272 | */ | |
273 | inet_bind_bucket_for_each(tb, node, &head->chain) { | |
274 | if (tb->port == port) { | |
275 | BUG_TRAP(!hlist_empty(&tb->owners)); | |
276 | if (tb->fastreuse >= 0) | |
277 | goto next_port; | |
278 | if (!__inet_check_established(death_row, | |
279 | sk, port, | |
280 | &tw)) | |
281 | goto ok; | |
282 | goto next_port; | |
283 | } | |
284 | } | |
285 | ||
286 | tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, head, port); | |
287 | if (!tb) { | |
288 | spin_unlock(&head->lock); | |
289 | break; | |
290 | } | |
291 | tb->fastreuse = -1; | |
292 | goto ok; | |
293 | ||
294 | next_port: | |
295 | spin_unlock(&head->lock); | |
296 | } | |
297 | local_bh_enable(); | |
298 | ||
299 | return -EADDRNOTAVAIL; | |
300 | ||
301 | ok: | |
302 | hint += i; | |
303 | ||
304 | /* Head lock still held and bh's disabled */ | |
305 | inet_bind_hash(sk, tb, port); | |
306 | if (sk_unhashed(sk)) { | |
307 | inet_sk(sk)->sport = htons(port); | |
308 | __inet_hash(hinfo, sk, 0); | |
309 | } | |
310 | spin_unlock(&head->lock); | |
311 | ||
312 | if (tw) { | |
53b3531b | 313 | inet_twsk_deschedule(tw, death_row); |
a7f5e7f1 ACM |
314 | inet_twsk_put(tw); |
315 | } | |
316 | ||
317 | ret = 0; | |
318 | goto out; | |
319 | } | |
320 | ||
321 | head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)]; | |
322 | tb = inet_csk(sk)->icsk_bind_hash; | |
323 | spin_lock_bh(&head->lock); | |
324 | if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { | |
325 | __inet_hash(hinfo, sk, 0); | |
326 | spin_unlock_bh(&head->lock); | |
327 | return 0; | |
328 | } else { | |
329 | spin_unlock(&head->lock); | |
330 | /* No definite answer... Walk to established hash table */ | |
331 | ret = __inet_check_established(death_row, sk, snum, NULL); | |
332 | out: | |
333 | local_bh_enable(); | |
334 | return ret; | |
335 | } | |
336 | } | |
337 | ||
338 | EXPORT_SYMBOL_GPL(inet_hash_connect); |