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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 | ||
16 | #include <linux/config.h> | |
2d8c4ce5 | 17 | #include <linux/module.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 ACM |
23 | #include <net/inet_hashtables.h> |
24 | ||
25 | /* | |
26 | * Allocate and initialize a new local port bind bucket. | |
27 | * The bindhash mutex for snum's hash chain must be held here. | |
28 | */ | |
29 | struct inet_bind_bucket *inet_bind_bucket_create(kmem_cache_t *cachep, | |
30 | struct inet_bind_hashbucket *head, | |
31 | const unsigned short snum) | |
32 | { | |
33 | struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, SLAB_ATOMIC); | |
34 | ||
35 | if (tb != NULL) { | |
36 | tb->port = snum; | |
37 | tb->fastreuse = 0; | |
38 | INIT_HLIST_HEAD(&tb->owners); | |
39 | hlist_add_head(&tb->node, &head->chain); | |
40 | } | |
41 | return tb; | |
42 | } | |
43 | ||
44 | EXPORT_SYMBOL(inet_bind_bucket_create); | |
45 | ||
46 | /* | |
47 | * Caller must hold hashbucket lock for this tb with local BH disabled | |
48 | */ | |
49 | void inet_bind_bucket_destroy(kmem_cache_t *cachep, struct inet_bind_bucket *tb) | |
50 | { | |
51 | if (hlist_empty(&tb->owners)) { | |
52 | __hlist_del(&tb->node); | |
53 | kmem_cache_free(cachep, tb); | |
54 | } | |
55 | } | |
2d8c4ce5 ACM |
56 | |
57 | void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, | |
58 | const unsigned short snum) | |
59 | { | |
463c84b9 | 60 | inet_sk(sk)->num = snum; |
2d8c4ce5 | 61 | sk_add_bind_node(sk, &tb->owners); |
463c84b9 | 62 | inet_csk(sk)->icsk_bind_hash = tb; |
2d8c4ce5 ACM |
63 | } |
64 | ||
65 | EXPORT_SYMBOL(inet_bind_hash); | |
66 | ||
67 | /* | |
68 | * Get rid of any references to a local port held by the given sock. | |
69 | */ | |
70 | static void __inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) | |
71 | { | |
463c84b9 | 72 | const int bhash = inet_bhashfn(inet_sk(sk)->num, hashinfo->bhash_size); |
2d8c4ce5 ACM |
73 | struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash]; |
74 | struct inet_bind_bucket *tb; | |
75 | ||
76 | spin_lock(&head->lock); | |
463c84b9 | 77 | tb = inet_csk(sk)->icsk_bind_hash; |
2d8c4ce5 | 78 | __sk_del_bind_node(sk); |
463c84b9 ACM |
79 | inet_csk(sk)->icsk_bind_hash = NULL; |
80 | inet_sk(sk)->num = 0; | |
2d8c4ce5 ACM |
81 | inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); |
82 | spin_unlock(&head->lock); | |
83 | } | |
84 | ||
85 | void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) | |
86 | { | |
87 | local_bh_disable(); | |
88 | __inet_put_port(hashinfo, sk); | |
89 | local_bh_enable(); | |
90 | } | |
91 | ||
92 | EXPORT_SYMBOL(inet_put_port); | |
f3f05f70 ACM |
93 | |
94 | /* | |
95 | * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP. | |
96 | * Look, when several writers sleep and reader wakes them up, all but one | |
97 | * immediately hit write lock and grab all the cpus. Exclusive sleep solves | |
98 | * this, _but_ remember, it adds useless work on UP machines (wake up each | |
99 | * exclusive lock release). It should be ifdefed really. | |
100 | */ | |
101 | void inet_listen_wlock(struct inet_hashinfo *hashinfo) | |
102 | { | |
103 | write_lock(&hashinfo->lhash_lock); | |
104 | ||
105 | if (atomic_read(&hashinfo->lhash_users)) { | |
106 | DEFINE_WAIT(wait); | |
107 | ||
108 | for (;;) { | |
109 | prepare_to_wait_exclusive(&hashinfo->lhash_wait, | |
110 | &wait, TASK_UNINTERRUPTIBLE); | |
111 | if (!atomic_read(&hashinfo->lhash_users)) | |
112 | break; | |
113 | write_unlock_bh(&hashinfo->lhash_lock); | |
114 | schedule(); | |
115 | write_lock_bh(&hashinfo->lhash_lock); | |
116 | } | |
117 | ||
118 | finish_wait(&hashinfo->lhash_wait, &wait); | |
119 | } | |
120 | } | |
121 | ||
122 | EXPORT_SYMBOL(inet_listen_wlock); | |
33b62231 ACM |
123 | |
124 | /* | |
125 | * Don't inline this cruft. Here are some nice properties to exploit here. The | |
126 | * BSD API does not allow a listening sock to specify the remote port nor the | |
127 | * remote address for the connection. So always assume those are both | |
128 | * wildcarded during the search since they can never be otherwise. | |
129 | */ | |
130 | struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 daddr, | |
131 | const unsigned short hnum, const int dif) | |
132 | { | |
133 | struct sock *result = NULL, *sk; | |
134 | const struct hlist_node *node; | |
135 | int hiscore = -1; | |
136 | ||
137 | sk_for_each(sk, node, head) { | |
138 | const struct inet_sock *inet = inet_sk(sk); | |
139 | ||
140 | if (inet->num == hnum && !ipv6_only_sock(sk)) { | |
141 | const __u32 rcv_saddr = inet->rcv_saddr; | |
142 | int score = sk->sk_family == PF_INET ? 1 : 0; | |
143 | ||
144 | if (rcv_saddr) { | |
145 | if (rcv_saddr != daddr) | |
146 | continue; | |
147 | score += 2; | |
148 | } | |
149 | if (sk->sk_bound_dev_if) { | |
150 | if (sk->sk_bound_dev_if != dif) | |
151 | continue; | |
152 | score += 2; | |
153 | } | |
154 | if (score == 5) | |
155 | return sk; | |
156 | if (score > hiscore) { | |
157 | hiscore = score; | |
158 | result = sk; | |
159 | } | |
160 | } | |
161 | } | |
162 | return result; | |
163 | } | |
e48c414e ACM |
164 | |
165 | EXPORT_SYMBOL_GPL(__inet_lookup_listener); |