| /* |
| * NET Generic infrastructure for Network protocols. |
| * |
| * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br> |
| * |
| * From code originally in include/net/tcp.h |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/random.h> |
| #include <linux/slab.h> |
| #include <linux/string.h> |
| |
| #include <net/request_sock.h> |
| |
| /* |
| * Maximum number of SYN_RECV sockets in queue per LISTEN socket. |
| * One SYN_RECV socket costs about 80bytes on a 32bit machine. |
| * It would be better to replace it with a global counter for all sockets |
| * but then some measure against one socket starving all other sockets |
| * would be needed. |
| * |
| * It was 128 by default. Experiments with real servers show, that |
| * it is absolutely not enough even at 100conn/sec. 256 cures most |
| * of problems. This value is adjusted to 128 for very small machines |
| * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb). |
| * Further increasing requires to change hash table size. |
| */ |
| int sysctl_max_syn_backlog = 256; |
| EXPORT_SYMBOL(sysctl_max_syn_backlog); |
| |
| int reqsk_queue_alloc(struct request_sock_queue *queue, |
| const int nr_table_entries) |
| { |
| const int lopt_size = sizeof(struct listen_sock) + |
| nr_table_entries * sizeof(struct request_sock *); |
| struct listen_sock *lopt = kmalloc(lopt_size, GFP_KERNEL); |
| |
| if (lopt == NULL) |
| return -ENOMEM; |
| |
| memset(lopt, 0, lopt_size); |
| |
| for (lopt->max_qlen_log = 6; |
| (1 << lopt->max_qlen_log) < sysctl_max_syn_backlog; |
| lopt->max_qlen_log++); |
| |
| get_random_bytes(&lopt->hash_rnd, sizeof(lopt->hash_rnd)); |
| rwlock_init(&queue->syn_wait_lock); |
| queue->rskq_accept_head = queue->rskq_accept_head = NULL; |
| lopt->nr_table_entries = nr_table_entries; |
| |
| write_lock_bh(&queue->syn_wait_lock); |
| queue->listen_opt = lopt; |
| write_unlock_bh(&queue->syn_wait_lock); |
| |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(reqsk_queue_alloc); |
| |
| void reqsk_queue_destroy(struct request_sock_queue *queue) |
| { |
| /* make all the listen_opt local to us */ |
| struct listen_sock *lopt = reqsk_queue_yank_listen_sk(queue); |
| |
| if (lopt->qlen != 0) { |
| int i; |
| |
| for (i = 0; i < lopt->nr_table_entries; i++) { |
| struct request_sock *req; |
| |
| while ((req = lopt->syn_table[i]) != NULL) { |
| lopt->syn_table[i] = req->dl_next; |
| lopt->qlen--; |
| reqsk_free(req); |
| } |
| } |
| } |
| |
| BUG_TRAP(lopt->qlen == 0); |
| kfree(lopt); |
| } |
| |
| EXPORT_SYMBOL(reqsk_queue_destroy); |