This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / net / core / request_sock.c

diff --git a/net/core/request_sock.c b/net/core/request_sock.c
new file mode 100644 (file)
index 0000000..79ebd75
--- /dev/null
+++ b/net/core/request_sock.c
@@ -0,0 +1,87 @@
+/*
+ * 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;
+
+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 = kzalloc(lopt_size, GFP_KERNEL);
+
+       if (lopt == NULL)
+               return -ENOMEM;
+
+       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 = 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);