[NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables
This monster-patch tries to do the best job for unifying the data
structures and backend interfaces for the three evil clones ip_tables,
ip6_tables and arp_tables. In an ideal world we would never have
allowed this kind of copy+paste programming... but well, our world
isn't (yet?) ideal.
o introduce a new x_tables module
o {ip,arp,ip6}_tables depend on this x_tables module
o registration functions for tables, matches and targets are only
wrappers around x_tables provided functions
o all matches/targets that are used from ip_tables and ip6_tables
are now implemented as xt_FOOBAR.c files and provide module aliases
to ipt_FOOBAR and ip6t_FOOBAR
o header files for xt_matches are in include/linux/netfilter/,
include/linux/netfilter_{ipv4,ipv6} contains compatibility wrappers
around the xt_FOOBAR.h headers
Based on this patchset we're going to further unify the code,
gradually getting rid of all the layer 3 specific assumptions.
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/xt_connbytes.c b/net/netfilter/xt_connbytes.c
new file mode 100644
index 0000000..150d2a4
--- /dev/null
+++ b/net/netfilter/xt_connbytes.c
@@ -0,0 +1,180 @@
+/* Kernel module to match connection tracking byte counter.
+ * GPL (C) 2002 Martin Devera (devik@cdi.cz).
+ *
+ * 2004-07-20 Harald Welte <laforge@netfilter.org>
+ * - reimplemented to use per-connection accounting counters
+ * - add functionality to match number of packets
+ * - add functionality to match average packet size
+ * - add support to match directions seperately
+ * 2005-10-16 Harald Welte <laforge@netfilter.org>
+ * - Port to x_tables
+ *
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <net/netfilter/nf_conntrack_compat.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_connbytes.h>
+
+#include <asm/div64.h>
+#include <asm/bitops.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_DESCRIPTION("iptables match for matching number of pkts/bytes per connection");
+MODULE_ALIAS("ipt_connbytes");
+
+/* 64bit divisor, dividend and result. dynamic precision */
+static u_int64_t div64_64(u_int64_t dividend, u_int64_t divisor)
+{
+ u_int32_t d = divisor;
+
+ if (divisor > 0xffffffffULL) {
+ unsigned int shift = fls(divisor >> 32);
+
+ d = divisor >> shift;
+ dividend >>= shift;
+ }
+
+ do_div(dividend, d);
+ return dividend;
+}
+
+static int
+match(const struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ const void *matchinfo,
+ int offset,
+ unsigned int protoff,
+ int *hotdrop)
+{
+ const struct xt_connbytes_info *sinfo = matchinfo;
+ u_int64_t what = 0; /* initialize to make gcc happy */
+ const struct ip_conntrack_counter *counters;
+
+ if (!(counters = nf_ct_get_counters(skb)))
+ return 0; /* no match */
+
+ switch (sinfo->what) {
+ case XT_CONNBYTES_PKTS:
+ switch (sinfo->direction) {
+ case XT_CONNBYTES_DIR_ORIGINAL:
+ what = counters[IP_CT_DIR_ORIGINAL].packets;
+ break;
+ case XT_CONNBYTES_DIR_REPLY:
+ what = counters[IP_CT_DIR_REPLY].packets;
+ break;
+ case XT_CONNBYTES_DIR_BOTH:
+ what = counters[IP_CT_DIR_ORIGINAL].packets;
+ what += counters[IP_CT_DIR_REPLY].packets;
+ break;
+ }
+ break;
+ case XT_CONNBYTES_BYTES:
+ switch (sinfo->direction) {
+ case XT_CONNBYTES_DIR_ORIGINAL:
+ what = counters[IP_CT_DIR_ORIGINAL].bytes;
+ break;
+ case XT_CONNBYTES_DIR_REPLY:
+ what = counters[IP_CT_DIR_REPLY].bytes;
+ break;
+ case XT_CONNBYTES_DIR_BOTH:
+ what = counters[IP_CT_DIR_ORIGINAL].bytes;
+ what += counters[IP_CT_DIR_REPLY].bytes;
+ break;
+ }
+ break;
+ case XT_CONNBYTES_AVGPKT:
+ switch (sinfo->direction) {
+ case XT_CONNBYTES_DIR_ORIGINAL:
+ what = div64_64(counters[IP_CT_DIR_ORIGINAL].bytes,
+ counters[IP_CT_DIR_ORIGINAL].packets);
+ break;
+ case XT_CONNBYTES_DIR_REPLY:
+ what = div64_64(counters[IP_CT_DIR_REPLY].bytes,
+ counters[IP_CT_DIR_REPLY].packets);
+ break;
+ case XT_CONNBYTES_DIR_BOTH:
+ {
+ u_int64_t bytes;
+ u_int64_t pkts;
+ bytes = counters[IP_CT_DIR_ORIGINAL].bytes +
+ counters[IP_CT_DIR_REPLY].bytes;
+ pkts = counters[IP_CT_DIR_ORIGINAL].packets+
+ counters[IP_CT_DIR_REPLY].packets;
+
+ /* FIXME_THEORETICAL: what to do if sum
+ * overflows ? */
+
+ what = div64_64(bytes, pkts);
+ }
+ break;
+ }
+ break;
+ }
+
+ if (sinfo->count.to)
+ return (what <= sinfo->count.to && what >= sinfo->count.from);
+ else
+ return (what >= sinfo->count.from);
+}
+
+static int check(const char *tablename,
+ const void *ip,
+ void *matchinfo,
+ unsigned int matchsize,
+ unsigned int hook_mask)
+{
+ const struct xt_connbytes_info *sinfo = matchinfo;
+
+ if (matchsize != XT_ALIGN(sizeof(struct xt_connbytes_info)))
+ return 0;
+
+ if (sinfo->what != XT_CONNBYTES_PKTS &&
+ sinfo->what != XT_CONNBYTES_BYTES &&
+ sinfo->what != XT_CONNBYTES_AVGPKT)
+ return 0;
+
+ if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL &&
+ sinfo->direction != XT_CONNBYTES_DIR_REPLY &&
+ sinfo->direction != XT_CONNBYTES_DIR_BOTH)
+ return 0;
+
+ return 1;
+}
+
+static struct xt_match connbytes_match = {
+ .name = "connbytes",
+ .match = &match,
+ .checkentry = &check,
+ .me = THIS_MODULE
+};
+static struct xt_match connbytes6_match = {
+ .name = "connbytes",
+ .match = &match,
+ .checkentry = &check,
+ .me = THIS_MODULE
+};
+
+static int __init init(void)
+{
+ int ret;
+ ret = xt_register_match(AF_INET, &connbytes_match);
+ if (ret)
+ return ret;
+
+ ret = xt_register_match(AF_INET6, &connbytes6_match);
+ if (ret)
+ xt_unregister_match(AF_INET, &connbytes_match);
+ return ret;
+}
+
+static void __exit fini(void)
+{
+ xt_unregister_match(AF_INET, &connbytes_match);
+ xt_unregister_match(AF_INET6, &connbytes6_match);
+}
+
+module_init(init);
+module_exit(fini);