[NETFILTER]: x_tables: add quota match

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 96 insertions, 0 deletions

diff --git a/net/netfilter/xt_quota.c b/net/netfilter/xt_quota.c
new file mode 100644
index 000000000000..4cdba7469dc4
--- /dev/null
+++ b/net/netfilter/xt_quota.c
@@ -0,0 +1,96 @@
+/*
+ * netfilter module to enforce network quotas
+ *
+ * Sam Johnston <samj@samj.net>
+ */
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_quota.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
+
+static DEFINE_SPINLOCK(quota_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_quota_info *q = ((struct xt_quota_info *)matchinfo)->master;
+	int ret = q->flags & XT_QUOTA_INVERT ? 1 : 0;
+
+	spin_lock_bh(&quota_lock);
+	if (q->quota >= skb->len) {
+		q->quota -= skb->len;
+		ret ^= 1;
+	} else {
+	        /* we do not allow even small packets from now on */
+	        q->quota = 0;
+	}
+	spin_unlock_bh(&quota_lock);
+
+	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_quota_info *q = (struct xt_quota_info *)matchinfo;
+
+	if (q->flags & ~XT_QUOTA_MASK)
+		return 0;
+	/* For SMP, we only want to use one set of counters. */
+	q->master = q;
+	return 1;
+}
+
+static struct xt_match quota_match = {
+	.name		= "quota",
+	.family		= AF_INET,
+	.match		= match,
+	.matchsize	= sizeof(struct xt_quota_info),
+	.checkentry	= checkentry,
+	.me		= THIS_MODULE
+};
+
+static struct xt_match quota_match6 = {
+	.name		= "quota",
+	.family		= AF_INET6,
+	.match		= match,
+	.matchsize	= sizeof(struct xt_quota_info),
+	.checkentry	= checkentry,
+	.me		= THIS_MODULE
+};
+
+static int __init xt_quota_init(void)
+{
+	int ret;
+
+	ret = xt_register_match(&quota_match);
+	if (ret)
+		goto err1;
+	ret = xt_register_match(&quota_match6);
+	if (ret)
+		goto err2;
+	return ret;
+
+err2:
+	xt_unregister_match(&quota_match);
+err1:
+	return ret;
+}
+
+static void __exit xt_quota_fini(void)
+{
+	xt_unregister_match(&quota_match6);
+	xt_unregister_match(&quota_match);
+}
+
+module_init(xt_quota_init);
+module_exit(xt_quota_fini);