IPMARK: import 20080304 code base

With truly minimal changes to make it compile.

extensions/xt_IPMARK.c

@@ -0,0 +1,59 @@
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/version.h>
+#include <linux/ip.h>
+#include <net/checksum.h>
+
+#include <linux/netfilter/x_tables.h>
+#include "xt_IPMARK.h"
+#include "compat_xtables.h"
+
+MODULE_AUTHOR("Grzegorz Janoszka <Grzegorz@Janoszka.pl>");
+MODULE_DESCRIPTION("IP tables IPMARK: mark based on ip address");
+MODULE_LICENSE("GPL");
+
+static unsigned int
+ipmark_tg(struct sk_buff *skb,
+       const struct net_device *in,
+       const struct net_device *out,
+       unsigned int hooknum,
+       const struct xt_target *target,
+       const void *targinfo)
+{
+	const struct ipt_ipmark_target_info *ipmarkinfo = targinfo;
+	struct iphdr *iph = ip_hdr(skb);
+	unsigned long mark;
+
+	if (ipmarkinfo->addr == IPT_IPMARK_SRC)
+		mark = (unsigned long) ntohl(iph->saddr);
+	else
+		mark = (unsigned long) ntohl(iph->daddr);
+
+	mark &= ipmarkinfo->andmask;
+	mark |= ipmarkinfo->ormask;
+
+	skb_nfmark(skb) = mark;
+	return XT_CONTINUE;
+}
+
+static struct xt_target ipt_ipmark_reg = {
+	.name		= "IPMARK",
+	.family		= AF_INET,
+	.table		= "mangle",
+	.target		= ipmark_tg,
+	.targetsize	= sizeof(struct ipt_ipmark_target_info),
+	.me		= THIS_MODULE
+};
+
+static int __init ipmark_tg_init(void)
+{
+	return xt_register_target(&ipt_ipmark_reg);
+}
+
+static void __exit ipmark_tg_exit(void)
+{
+	xt_unregister_target(&ipt_ipmark_reg);
+}
+
+module_init(ipmark_tg_init);
+module_exit(ipmark_tg_exit);