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

[linux-2.6.git] / net / netfilter / xt_statistic.c

diff --git a/net/netfilter/xt_statistic.c b/net/netfilter/xt_statistic.c
new file mode 100644 (file)
index 0000000..de1037f
--- /dev/null
+++ b/net/netfilter/xt_statistic.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>.
+ */
+
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/skbuff.h>
+#include <linux/net.h>
+
+#include <linux/netfilter/xt_statistic.h>
+#include <linux/netfilter/x_tables.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("xtables statistical match module");
+MODULE_ALIAS("ipt_statistic");
+MODULE_ALIAS("ip6t_statistic");
+
+static DEFINE_SPINLOCK(nth_lock);
+
+static int
+match(const struct sk_buff *skb,
+      const struct net_device *in, const struct net_device *out,
+      const struct xt_match *match, const void *matchinfo,
+      int offset, unsigned int protoff, int *hotdrop)
+{
+       struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
+       int ret = info->flags & XT_STATISTIC_INVERT ? 1 : 0;
+
+       switch (info->mode) {
+       case XT_STATISTIC_MODE_RANDOM:
+               if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
+                       ret ^= 1;
+               break;
+       case XT_STATISTIC_MODE_NTH:
+               info = info->master;
+               spin_lock_bh(&nth_lock);
+               if (info->u.nth.count++ == info->u.nth.every) {
+                       info->u.nth.count = 0;
+                       ret ^= 1;
+               }
+               spin_unlock_bh(&nth_lock);
+               break;
+       }
+
+       return ret;
+}
+
+static int
+checkentry(const char *tablename, const void *entry,
+          const struct xt_match *match, void *matchinfo,
+          unsigned int matchsize, unsigned int hook_mask)
+{
+       struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
+
+       if (info->mode > XT_STATISTIC_MODE_MAX ||
+           info->flags & ~XT_STATISTIC_MASK)
+               return 0;
+       info->master = info;
+       return 1;
+}
+
+static struct xt_match statistic_match = {
+       .name           = "statistic",
+       .match          = match,
+       .matchsize      = sizeof(struct xt_statistic_info),
+       .checkentry     = checkentry,
+       .family         = AF_INET,
+       .me             = THIS_MODULE,
+};
+
+static struct xt_match statistic_match6 = {
+       .name           = "statistic",
+       .match          = match,
+       .matchsize      = sizeof(struct xt_statistic_info),
+       .checkentry     = checkentry,
+       .family         = AF_INET6,
+       .me             = THIS_MODULE,
+};
+
+static int __init xt_statistic_init(void)
+{
+       int ret;
+
+       ret = xt_register_match(&statistic_match);
+       if (ret)
+               goto err1;
+
+       ret = xt_register_match(&statistic_match6);
+       if (ret)
+               goto err2;
+       return ret;
+err2:
+       xt_unregister_match(&statistic_match);
+err1:
+       return ret;
+}
+
+static void __exit xt_statistic_fini(void)
+{
+       xt_unregister_match(&statistic_match6);
+       xt_unregister_match(&statistic_match);
+}
+
+module_init(xt_statistic_init);
+module_exit(xt_statistic_fini);