netfilter: xtables: add nfacct match to support extended accounting

This patch adds the match that allows to perform extended
accounting. It requires the new nfnetlink_acct infrastructure.

 # iptables -I INPUT -p tcp --sport 80 -m nfacct --nfacct-name http-traffic
 # iptables -I OUTPUT -p tcp --dport 80 -m nfacct --nfacct-name http-traffic

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

3 files changed, 87 insertions, 0 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 77326acd1f57..bac93ba60778 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -887,6 +887,16 @@ config NETFILTER_XT_MATCH_MULTIPORT
 
           To compile it as a module, choose M here.  If unsure, say N.
 
+config NETFILTER_XT_MATCH_NFACCT
+        tristate '"nfacct" match support'
+        default m if NETFILTER_ADVANCED=n
+        select NETFILTER_NETLINK_ACCT
+        help
+          This option allows you to use the extended accounting through
+          nfnetlink_acct.
+
+          To compile it as a module, choose M here.  If unsure, say N.
+
 config NETFILTER_XT_MATCH_OSF
         tristate '"osf" Passive OS fingerprint match'
         depends on NETFILTER_ADVANCED && NETFILTER_NETLINK
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 4da1c879644f..b2eee4df8168 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_LENGTH) += xt_length.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LIMIT) += xt_limit.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_MAC) += xt_mac.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_MULTIPORT) += xt_multiport.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_NFACCT) += xt_nfacct.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_OSF) += xt_osf.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_OWNER) += xt_owner.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o
diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c
new file mode 100644
index 000000000000..b3be0ef21f19
--- /dev/null
+++ b/net/netfilter/xt_nfacct.c
@@ -0,0 +1,76 @@
+/*
+ * (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
+ * (C) 2011 Intra2net AG <http://www.intra2net.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 (or any
+ * later at your option) as published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/nfnetlink_acct.h>
+#include <linux/netfilter/xt_nfacct.h>
+
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_DESCRIPTION("Xtables: match for the extended accounting infrastructure");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_nfacct");
+MODULE_ALIAS("ip6t_nfacct");
+
+static bool nfacct_mt(const struct sk_buff *skb, struct xt_action_param *par)
+{
+        const struct xt_nfacct_match_info *info = par->targinfo;
+
+        nfnl_acct_update(skb, info->nfacct);
+
+        return true;
+}
+
+static int
+nfacct_mt_checkentry(const struct xt_mtchk_param *par)
+{
+        struct xt_nfacct_match_info *info = par->matchinfo;
+        struct nf_acct *nfacct;
+
+        nfacct = nfnl_acct_find_get(info->name);
+        if (nfacct == NULL) {
+                pr_info("xt_nfacct: accounting object with name `%s' "
+                        "does not exists\n", info->name);
+                return -ENOENT;
+        }
+        info->nfacct = nfacct;
+        return 0;
+}
+
+static void
+nfacct_mt_destroy(const struct xt_mtdtor_param *par)
+{
+        const struct xt_nfacct_match_info *info = par->matchinfo;
+
+        nfnl_acct_put(info->nfacct);
+}
+
+static struct xt_match nfacct_mt_reg __read_mostly = {
+        .name       = "nfacct",
+        .family     = NFPROTO_UNSPEC,
+        .checkentry = nfacct_mt_checkentry,
+        .match      = nfacct_mt,
+        .destroy    = nfacct_mt_destroy,
+        .matchsize  = sizeof(struct xt_nfacct_match_info),
+        .me         = THIS_MODULE,
+};
+
+static int __init nfacct_mt_init(void)
+{
+        return xt_register_match(&nfacct_mt_reg);
+}
+
+static void __exit nfacct_mt_exit(void)
+{
+        xt_unregister_match(&nfacct_mt_reg);
+}
+
+module_init(nfacct_mt_init);
+module_exit(nfacct_mt_exit);