patch-2.4.20 linux-2.4.20/net/ipv4/netfilter/ipt_helper.c

• Lines: 113
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/net/ipv4/netfilter/ipt_helper.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/net/ipv4/netfilter/ipt_helper.c linux-2.4.20/net/ipv4/netfilter/ipt_helper.c
@@ -0,0 +1,112 @@
+/*
+ * iptables module to match on related connections
+ *   (c) 2001 Martin Josefsson <gandalf@wlug.westbo.se>
+ *
+ * Released under the terms of GNU GPLv2.
+ *
+ *   19 Mar 2002 Harald Welte <laforge@gnumonks.org>:
+ *   		 - Port to newnat infrastructure
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter_ipv4/ip_conntrack.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");
+
+#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,
+      const void *hdr,
+      u_int16_t datalen,
+      int *hotdrop)
+{
+	const struct ipt_helper_info *info = matchinfo;
+	struct ip_conntrack_expect *exp;
+	struct ip_conntrack *ct;
+	enum ip_conntrack_info ctinfo;
+	
+	ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo);
+	if (!ct) {
+		DEBUGP("ipt_helper: Eek! invalid conntrack?\n");
+		return 0;
+	}
+
+	if (!ct->master) {
+		DEBUGP("ipt_helper: conntrack %p has no master\n", ct);
+		return 0;
+	}
+
+	exp = ct->master;
+	if (!exp->expectant) {
+		DEBUGP("ipt_helper: expectation %p without expectant !?!\n", 
+			exp);
+		return 0;
+	}
+
+	if (!exp->expectant->helper) {
+		DEBUGP("ipt_helper: master ct %p has no helper\n", 
+			exp->expectant);
+		return 0;
+	}
+
+	DEBUGP("master's name = %s , info->name = %s\n", 
+		exp->expectant->helper->name, info->name);
+
+	return !strncmp(exp->expectant->helper->name, info->name, 
+			strlen(exp->expectant->helper->name)) ^ info->invert;
+}
+
+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;
+
+	/* verify that we actually should match anything */
+	if ( strlen(info->name) == 0 )
+		return 0;
+	
+	return 1;
+}
+
+static struct ipt_match helper_match
+= { { NULL, NULL }, "helper", &match, &check, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+	/* NULL if ip_conntrack not a module */
+	if (ip_conntrack_module)
+		__MOD_INC_USE_COUNT(ip_conntrack_module);
+	return ipt_register_match(&helper_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&helper_match);
+	if (ip_conntrack_module)
+		__MOD_DEC_USE_COUNT(ip_conntrack_module);
+}
+
+module_init(init);
+module_exit(fini);
+