[NETFILTER]: x_tables: add quota match

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

diff --git a/include/linux/netfilter/xt_quota.h b/include/linux/netfilter/xt_quota.h
new file mode 100644 (file)
index 0000000..acd7fd7
--- /dev/null
+++ b/include/linux/netfilter/xt_quota.h
@@ -0,0 +1,16 @@
+#ifndef _XT_QUOTA_H
+#define _XT_QUOTA_H
+
+enum xt_quota_flags {
+       XT_QUOTA_INVERT         = 0x1,
+};
+#define XT_QUOTA_MASK          0x1
+
+struct xt_quota_info {
+       u_int32_t               flags;
+       u_int32_t               pad;
+       aligned_u64             quota;
+       struct xt_quota_info    *master;
+};
+
+#endif /* _XT_QUOTA_H */

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index e2893ef..5543c7b 100644 (file)
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -329,6 +329,16 @@ config NETFILTER_XT_MATCH_PKTTYPE
 
          To compile it as a module, choose M here.  If unsure, say N.
 
+config NETFILTER_XT_MATCH_QUOTA
+       tristate '"quota" match support'
+       depends on NETFILTER_XTABLES
+       help
+         This option adds a `quota' match, which allows to match on a
+         byte counter.
+
+         If you want to compile it as a module, say M here and read
+         <file:Documentation/modules.txt>.  If unsure, say `N'.
+
 config NETFILTER_XT_MATCH_REALM
        tristate  '"realm" match support'
        depends on NETFILTER_XTABLES

diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 95b7e41..4b6a6ea 100644 (file)
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_MARK) += xt_mark.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_MULTIPORT) += xt_multiport.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_POLICY) += xt_policy.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_PKTTYPE) += xt_pkttype.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_QUOTA) += xt_quota.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_REALM) += xt_realm.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_SCTP) += xt_sctp.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_STATE) += xt_state.o

diff --git a/net/netfilter/xt_quota.c b/net/netfilter/xt_quota.c
new file mode 100644 (file)
index 0000000..4cdba74
--- /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);