2 * NET Generic infrastructure for Network protocols.
4 * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 * From code originally in include/net/tcp.h
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.
14 #include <linux/module.h>
15 #include <linux/random.h>
16 #include <linux/slab.h>
17 #include <linux/string.h>
18 #include <linux/vmalloc.h>
20 #include <net/request_sock.h>
23 * Maximum number of SYN_RECV sockets in queue per LISTEN socket.
24 * One SYN_RECV socket costs about 80bytes on a 32bit machine.
25 * It would be better to replace it with a global counter for all sockets
26 * but then some measure against one socket starving all other sockets
29 * It was 128 by default. Experiments with real servers show, that
30 * it is absolutely not enough even at 100conn/sec. 256 cures most
31 * of problems. This value is adjusted to 128 for very small machines
32 * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).
33 * Note : Dont forget somaxconn that may limit backlog too.
35 int sysctl_max_syn_backlog
= 256;
37 int reqsk_queue_alloc(struct request_sock_queue
*queue
,
38 unsigned int nr_table_entries
)
40 size_t lopt_size
= sizeof(struct listen_sock
);
41 struct listen_sock
*lopt
;
43 nr_table_entries
= min_t(u32
, nr_table_entries
, sysctl_max_syn_backlog
);
44 nr_table_entries
= max_t(u32
, nr_table_entries
, 8);
45 nr_table_entries
= roundup_pow_of_two(nr_table_entries
+ 1);
46 lopt_size
+= nr_table_entries
* sizeof(struct request_sock
*);
47 if (lopt_size
> PAGE_SIZE
)
48 lopt
= vzalloc(lopt_size
);
50 lopt
= kzalloc(lopt_size
, GFP_KERNEL
);
54 for (lopt
->max_qlen_log
= 3;
55 (1 << lopt
->max_qlen_log
) < nr_table_entries
;
56 lopt
->max_qlen_log
++);
58 get_random_bytes(&lopt
->hash_rnd
, sizeof(lopt
->hash_rnd
));
59 rwlock_init(&queue
->syn_wait_lock
);
60 queue
->rskq_accept_head
= NULL
;
61 lopt
->nr_table_entries
= nr_table_entries
;
63 write_lock_bh(&queue
->syn_wait_lock
);
64 queue
->listen_opt
= lopt
;
65 write_unlock_bh(&queue
->syn_wait_lock
);
70 void __reqsk_queue_destroy(struct request_sock_queue
*queue
)
72 struct listen_sock
*lopt
;
76 * this is an error recovery path only
77 * no locking needed and the lopt is not NULL
80 lopt
= queue
->listen_opt
;
81 lopt_size
= sizeof(struct listen_sock
) +
82 lopt
->nr_table_entries
* sizeof(struct request_sock
*);
84 if (lopt_size
> PAGE_SIZE
)
90 static inline struct listen_sock
*reqsk_queue_yank_listen_sk(
91 struct request_sock_queue
*queue
)
93 struct listen_sock
*lopt
;
95 write_lock_bh(&queue
->syn_wait_lock
);
96 lopt
= queue
->listen_opt
;
97 queue
->listen_opt
= NULL
;
98 write_unlock_bh(&queue
->syn_wait_lock
);
103 void reqsk_queue_destroy(struct request_sock_queue
*queue
)
105 /* make all the listen_opt local to us */
106 struct listen_sock
*lopt
= reqsk_queue_yank_listen_sk(queue
);
107 size_t lopt_size
= sizeof(struct listen_sock
) +
108 lopt
->nr_table_entries
* sizeof(struct request_sock
*);
110 if (lopt
->qlen
!= 0) {
113 for (i
= 0; i
< lopt
->nr_table_entries
; i
++) {
114 struct request_sock
*req
;
116 while ((req
= lopt
->syn_table
[i
]) != NULL
) {
117 lopt
->syn_table
[i
] = req
->dl_next
;
124 WARN_ON(lopt
->qlen
!= 0);
125 if (lopt_size
> PAGE_SIZE
)
This page took 0.032217 seconds and 5 git commands to generate.