Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / net / netfilter / xt_statistic.c

diff --git a/kernel/net/netfilter/xt_statistic.c b/kernel/net/netfilter/xt_statistic.c
new file mode 100644 (file)
index 0000000..11de55e
--- /dev/null
+++ b/kernel/net/netfilter/xt_statistic.c
@@ -0,0 +1,101 @@
+/*
+ * 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/slab.h>
+
+#include <linux/netfilter/xt_statistic.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/module.h>
+
+struct xt_statistic_priv {
+       atomic_t count;
+} ____cacheline_aligned_in_smp;
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)");
+MODULE_ALIAS("ipt_statistic");
+MODULE_ALIAS("ip6t_statistic");
+
+static bool
+statistic_mt(const struct sk_buff *skb, struct xt_action_param *par)
+{
+       const struct xt_statistic_info *info = par->matchinfo;
+       bool ret = info->flags & XT_STATISTIC_INVERT;
+       int nval, oval;
+
+       switch (info->mode) {
+       case XT_STATISTIC_MODE_RANDOM:
+               if ((prandom_u32() & 0x7FFFFFFF) < info->u.random.probability)
+                       ret = !ret;
+               break;
+       case XT_STATISTIC_MODE_NTH:
+               do {
+                       oval = atomic_read(&info->master->count);
+                       nval = (oval == info->u.nth.every) ? 0 : oval + 1;
+               } while (atomic_cmpxchg(&info->master->count, oval, nval) != oval);
+               if (nval == 0)
+                       ret = !ret;
+               break;
+       }
+
+       return ret;
+}
+
+static int statistic_mt_check(const struct xt_mtchk_param *par)
+{
+       struct xt_statistic_info *info = par->matchinfo;
+
+       if (info->mode > XT_STATISTIC_MODE_MAX ||
+           info->flags & ~XT_STATISTIC_MASK)
+               return -EINVAL;
+
+       info->master = kzalloc(sizeof(*info->master), GFP_KERNEL);
+       if (info->master == NULL)
+               return -ENOMEM;
+       atomic_set(&info->master->count, info->u.nth.count);
+
+       return 0;
+}
+
+static void statistic_mt_destroy(const struct xt_mtdtor_param *par)
+{
+       const struct xt_statistic_info *info = par->matchinfo;
+
+       kfree(info->master);
+}
+
+static struct xt_match xt_statistic_mt_reg __read_mostly = {
+       .name       = "statistic",
+       .revision   = 0,
+       .family     = NFPROTO_UNSPEC,
+       .match      = statistic_mt,
+       .checkentry = statistic_mt_check,
+       .destroy    = statistic_mt_destroy,
+       .matchsize  = sizeof(struct xt_statistic_info),
+       .me         = THIS_MODULE,
+};
+
+static int __init statistic_mt_init(void)
+{
+       return xt_register_match(&xt_statistic_mt_reg);
+}
+
+static void __exit statistic_mt_exit(void)
+{
+       xt_unregister_match(&xt_statistic_mt_reg);
+}
+
+module_init(statistic_mt_init);
+module_exit(statistic_mt_exit);