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0e87506f ACM |
1 | /* |
2 | * NET Generic infrastructure for Network protocols. | |
3 | * | |
4 | * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
5 | * | |
6 | * From code originally in include/net/tcp.h | |
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 | #include <linux/module.h> | |
15 | #include <linux/random.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/string.h> | |
18 | ||
19 | #include <net/request_sock.h> | |
20 | ||
e52c1f17 DM |
21 | /* |
22 | * Maximum number of SYN_RECV sockets in queue per LISTEN socket. | |
23 | * One SYN_RECV socket costs about 80bytes on a 32bit machine. | |
24 | * It would be better to replace it with a global counter for all sockets | |
25 | * but then some measure against one socket starving all other sockets | |
26 | * would be needed. | |
27 | * | |
28 | * It was 128 by default. Experiments with real servers show, that | |
29 | * it is absolutely not enough even at 100conn/sec. 256 cures most | |
30 | * of problems. This value is adjusted to 128 for very small machines | |
31 | * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb). | |
32 | * Further increasing requires to change hash table size. | |
33 | */ | |
34 | int sysctl_max_syn_backlog = 256; | |
e52c1f17 | 35 | |
0e87506f ACM |
36 | int reqsk_queue_alloc(struct request_sock_queue *queue, |
37 | const int nr_table_entries) | |
38 | { | |
2ad69c55 | 39 | const int lopt_size = sizeof(struct listen_sock) + |
0e87506f | 40 | nr_table_entries * sizeof(struct request_sock *); |
77d04bd9 | 41 | struct listen_sock *lopt = kzalloc(lopt_size, GFP_KERNEL); |
0e87506f ACM |
42 | |
43 | if (lopt == NULL) | |
44 | return -ENOMEM; | |
45 | ||
0e87506f ACM |
46 | for (lopt->max_qlen_log = 6; |
47 | (1 << lopt->max_qlen_log) < sysctl_max_syn_backlog; | |
48 | lopt->max_qlen_log++); | |
49 | ||
50 | get_random_bytes(&lopt->hash_rnd, sizeof(lopt->hash_rnd)); | |
51 | rwlock_init(&queue->syn_wait_lock); | |
3eb4801d | 52 | queue->rskq_accept_head = NULL; |
83e3609e | 53 | lopt->nr_table_entries = nr_table_entries; |
0e87506f ACM |
54 | |
55 | write_lock_bh(&queue->syn_wait_lock); | |
56 | queue->listen_opt = lopt; | |
57 | write_unlock_bh(&queue->syn_wait_lock); | |
58 | ||
59 | return 0; | |
60 | } | |
61 | ||
62 | EXPORT_SYMBOL(reqsk_queue_alloc); | |
83e3609e ACM |
63 | |
64 | void reqsk_queue_destroy(struct request_sock_queue *queue) | |
65 | { | |
66 | /* make all the listen_opt local to us */ | |
67 | struct listen_sock *lopt = reqsk_queue_yank_listen_sk(queue); | |
68 | ||
69 | if (lopt->qlen != 0) { | |
70 | int i; | |
71 | ||
72 | for (i = 0; i < lopt->nr_table_entries; i++) { | |
73 | struct request_sock *req; | |
74 | ||
75 | while ((req = lopt->syn_table[i]) != NULL) { | |
76 | lopt->syn_table[i] = req->dl_next; | |
77 | lopt->qlen--; | |
78 | reqsk_free(req); | |
79 | } | |
80 | } | |
81 | } | |
82 | ||
83 | BUG_TRAP(lopt->qlen == 0); | |
84 | kfree(lopt); | |
85 | } | |
86 | ||
87 | EXPORT_SYMBOL(reqsk_queue_destroy); |