1 files changed, 113 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_helper.c b/net/ipv4/netfilter/ipt_helper.c
new file mode 100644
index 00000000000..33fdf364d3d
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_helper.c
@@ -0,0 +1,113 @@
+/* iptables module to match on related connections */
+/*
+ * (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *   19 Mar 2002 Harald Welte <laforge@gnumonks.org>:
+ *   		 - Port to newnat infrastructure
+ */
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4/ip_conntrack.h>
+#include <linux/netfilter_ipv4/ip_conntrack_core.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_helper.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>");
+MODULE_DESCRIPTION("iptables helper match module");
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+static int
+match(const struct sk_buff *skb,
+      const struct net_device *in,
+      const struct net_device *out,
+      const void *matchinfo,
+      int offset,
+      int *hotdrop)
+{
+	const struct ipt_helper_info *info = matchinfo;
+	struct ip_conntrack *ct;
+	enum ip_conntrack_info ctinfo;
+	int ret = info->invert;
+	
+	ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo);
+	if (!ct) {
+		DEBUGP("ipt_helper: Eek! invalid conntrack?\n");
+		return ret;
+	}
+
+	if (!ct->master) {
+		DEBUGP("ipt_helper: conntrack %p has no master\n", ct);
+		return ret;
+	}
+
+	READ_LOCK(&ip_conntrack_lock);
+	if (!ct->master->helper) {
+		DEBUGP("ipt_helper: master ct %p has no helper\n", 
+			exp->expectant);
+		goto out_unlock;
+	}
+
+	DEBUGP("master's name = %s , info->name = %s\n", 
+		ct->master->helper->name, info->name);
+
+	if (info->name[0] == '\0')
+		ret ^= 1;
+	else
+		ret ^= !strncmp(ct->master->helper->name, info->name, 
+		                strlen(ct->master->helper->name));
+out_unlock:
+	READ_UNLOCK(&ip_conntrack_lock);
+	return ret;
+}
+
+static int check(const char *tablename,
+		 const struct ipt_ip *ip,
+		 void *matchinfo,
+		 unsigned int matchsize,
+		 unsigned int hook_mask)
+{
+	struct ipt_helper_info *info = matchinfo;
+
+	info->name[29] = '\0';
+
+	/* verify size */
+	if (matchsize != IPT_ALIGN(sizeof(struct ipt_helper_info)))
+		return 0;
+
+	return 1;
+}
+
+static struct ipt_match helper_match = {
+	.name		= "helper",
+	.match		= &match,
+	.checkentry	= &check,
+	.me		= THIS_MODULE,
+};
+
+static int __init init(void)
+{
+	need_ip_conntrack();
+	return ipt_register_match(&helper_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&helper_match);
+}
+
+module_init(init);
+module_exit(fini);
+