1 files changed, 64 insertions, 0 deletions
diff --git a/net/core/request_sock.c b/net/core/request_sock.c
new file mode 100644
index 00000000000..bb55675f068
--- /dev/null
+++ b/net/core/request_sock.c
@@ -0,0 +1,64 @@
+/*
+ * 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;
+
+	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);