[NETFILTER]: x_tables: unify IPv4/IPv6 multiport match

This unifies ipt_multiport and ip6t_multiport to xt_multiport.
As a result, this addes support for inversion and port range match
to IPv6 packets.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 325 insertions, 0 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 5fe5189..e2893ef 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -298,6 +298,16 @@ config NETFILTER_XT_MATCH_POLICY
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config NETFILTER_XT_MATCH_MULTIPORT
+	tristate "Multiple port match support"
+	depends on NETFILTER_XTABLES
+	help
+	  Multiport matching allows you to match TCP or UDP packets based on
+	  a series of source or destination ports: normally a rule can only
+	  match a single range of ports.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 config NETFILTER_XT_MATCH_PHYSDEV
 	tristate '"physdev" match support'
 	depends on NETFILTER_XTABLES && BRIDGE_NETFILTER
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 8f02486..95b7e41 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -41,6 +41,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_LENGTH) += xt_length.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LIMIT) += xt_limit.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_MAC) += xt_mac.o
 obj-$(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_REALM) += xt_realm.o
diff --git a/net/netfilter/xt_multiport.c b/net/netfilter/xt_multiport.c
new file mode 100644
index 0000000..b56cd2b
--- /dev/null
+++ b/net/netfilter/xt_multiport.c
@@ -0,0 +1,314 @@
+/* Kernel module to match one of a list of TCP/UDP ports: ports are in
+   the same place so we can treat them as equal. */
+
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/udp.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+
+#include <linux/netfilter/xt_multiport.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("x_tables multiple port match module");
+MODULE_ALIAS("ipt_multiport");
+MODULE_ALIAS("ip6t_multiport");
+
+#if 0
+#define duprintf(format, args...) printk(format , ## args)
+#else
+#define duprintf(format, args...)
+#endif
+
+/* Returns 1 if the port is matched by the test, 0 otherwise. */
+static inline int
+ports_match(const u_int16_t *portlist, enum xt_multiport_flags flags,
+	    u_int8_t count, u_int16_t src, u_int16_t dst)
+{
+	unsigned int i;
+	for (i = 0; i < count; i++) {
+		if (flags != XT_MULTIPORT_DESTINATION && portlist[i] == src)
+			return 1;
+
+		if (flags != XT_MULTIPORT_SOURCE && portlist[i] == dst)
+			return 1;
+	}
+
+	return 0;
+}
+
+/* Returns 1 if the port is matched by the test, 0 otherwise. */
+static inline int
+ports_match_v1(const struct xt_multiport_v1 *minfo,
+	       u_int16_t src, u_int16_t dst)
+{
+	unsigned int i;
+	u_int16_t s, e;
+
+	for (i = 0; i < minfo->count; i++) {
+		s = minfo->ports[i];
+
+		if (minfo->pflags[i]) {
+			/* range port matching */
+			e = minfo->ports[++i];
+			duprintf("src or dst matches with %d-%d?\n", s, e);
+
+			if (minfo->flags == XT_MULTIPORT_SOURCE
+			    && src >= s && src <= e)
+				return 1 ^ minfo->invert;
+			if (minfo->flags == XT_MULTIPORT_DESTINATION
+			    && dst >= s && dst <= e)
+				return 1 ^ minfo->invert;
+			if (minfo->flags == XT_MULTIPORT_EITHER
+			    && ((dst >= s && dst <= e)
+				|| (src >= s && src <= e)))
+				return 1 ^ minfo->invert;
+		} else {
+			/* exact port matching */
+			duprintf("src or dst matches with %d?\n", s);
+
+			if (minfo->flags == XT_MULTIPORT_SOURCE
+			    && src == s)
+				return 1 ^ minfo->invert;
+			if (minfo->flags == XT_MULTIPORT_DESTINATION
+			    && dst == s)
+				return 1 ^ minfo->invert;
+			if (minfo->flags == XT_MULTIPORT_EITHER
+			    && (src == s || dst == s))
+				return 1 ^ minfo->invert;
+		}
+	}
+
+ 	return minfo->invert;
+}
+
+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)
+{
+	u16 _ports[2], *pptr;
+	const struct xt_multiport *multiinfo = matchinfo;
+
+	if (offset)
+		return 0;
+
+	pptr = skb_header_pointer(skb, protoff, sizeof(_ports), _ports);
+	if (pptr == NULL) {
+		/* We've been asked to examine this packet, and we
+		 * can't.  Hence, no choice but to drop.
+		 */
+		duprintf("xt_multiport: Dropping evil offset=0 tinygram.\n");
+		*hotdrop = 1;
+		return 0;
+	}
+
+	return ports_match(multiinfo->ports,
+			   multiinfo->flags, multiinfo->count,
+			   ntohs(pptr[0]), ntohs(pptr[1]));
+}
+
+static int
+match_v1(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)
+{
+	u16 _ports[2], *pptr;
+	const struct xt_multiport_v1 *multiinfo = matchinfo;
+
+	if (offset)
+		return 0;
+
+	pptr = skb_header_pointer(skb, protoff, sizeof(_ports), _ports);
+	if (pptr == NULL) {
+		/* We've been asked to examine this packet, and we
+		 * can't.  Hence, no choice but to drop.
+		 */
+		duprintf("xt_multiport: Dropping evil offset=0 tinygram.\n");
+		*hotdrop = 1;
+		return 0;
+	}
+
+	return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1]));
+}
+
+static inline int
+check(u_int16_t proto,
+      u_int8_t ip_invflags,
+      u_int8_t match_flags,
+      u_int8_t count)
+{
+	/* Must specify proto == TCP/UDP, no unknown flags or bad count */
+	return (proto == IPPROTO_TCP || proto == IPPROTO_UDP)
+		&& !(ip_invflags & XT_INV_PROTO)
+		&& (match_flags == XT_MULTIPORT_SOURCE
+		    || match_flags == XT_MULTIPORT_DESTINATION
+		    || match_flags == XT_MULTIPORT_EITHER)
+		&& count <= XT_MULTI_PORTS;
+}
+
+/* Called when user tries to insert an entry of this type. */
+static int
+checkentry(const char *tablename,
+	   const void *info,
+	   const struct xt_match *match,
+	   void *matchinfo,
+	   unsigned int matchsize,
+	   unsigned int hook_mask)
+{
+	const struct ipt_ip *ip = info;
+	const struct xt_multiport *multiinfo = matchinfo;
+
+	return check(ip->proto, ip->invflags, multiinfo->flags,
+		     multiinfo->count);
+}
+
+static int
+checkentry_v1(const char *tablename,
+	      const void *info,
+	      const struct xt_match *match,
+	      void *matchinfo,
+	      unsigned int matchsize,
+	      unsigned int hook_mask)
+{
+	const struct ipt_ip *ip = info;
+	const struct xt_multiport_v1 *multiinfo = matchinfo;
+
+	return check(ip->proto, ip->invflags, multiinfo->flags,
+		     multiinfo->count);
+}
+
+static int
+checkentry6(const char *tablename,
+	    const void *info,
+	    const struct xt_match *match,
+	    void *matchinfo,
+	    unsigned int matchsize,
+	    unsigned int hook_mask)
+{
+	const struct ip6t_ip6 *ip = info;
+	const struct xt_multiport *multiinfo = matchinfo;
+
+	return check(ip->proto, ip->invflags, multiinfo->flags,
+		     multiinfo->count);
+}
+
+static int
+checkentry6_v1(const char *tablename,
+	       const void *info,
+	       const struct xt_match *match,
+	       void *matchinfo,
+	       unsigned int matchsize,
+	       unsigned int hook_mask)
+{
+	const struct ip6t_ip6 *ip = info;
+	const struct xt_multiport_v1 *multiinfo = matchinfo;
+
+	return check(ip->proto, ip->invflags, multiinfo->flags,
+		     multiinfo->count);
+}
+
+static struct xt_match multiport_match = {
+	.name		= "multiport",
+	.revision	= 0,
+	.matchsize	= sizeof(struct xt_multiport),
+	.match		= &match,
+	.checkentry	= &checkentry,
+	.family		= AF_INET,
+	.me		= THIS_MODULE,
+};
+
+static struct xt_match multiport_match_v1 = {
+	.name		= "multiport",
+	.revision	= 1,
+	.matchsize	= sizeof(struct xt_multiport_v1),
+	.match		= &match_v1,
+	.checkentry	= &checkentry_v1,
+	.family		= AF_INET,
+	.me		= THIS_MODULE,
+};
+
+static struct xt_match multiport6_match = {
+	.name		= "multiport",
+	.revision	= 0,
+	.matchsize	= sizeof(struct xt_multiport),
+	.match		= &match,
+	.checkentry	= &checkentry6,
+	.family		= AF_INET6,
+	.me		= THIS_MODULE,
+};
+
+static struct xt_match multiport6_match_v1 = {
+	.name		= "multiport",
+	.revision	= 1,
+	.matchsize	= sizeof(struct xt_multiport_v1),
+	.match		= &match_v1,
+	.checkentry	= &checkentry6_v1,
+	.family		= AF_INET6,
+	.me		= THIS_MODULE,
+};
+
+static int __init xt_multiport_init(void)
+{
+	int ret;
+
+	ret = xt_register_match(&multiport_match);
+	if (ret)
+		goto out;
+
+	ret = xt_register_match(&multiport_match_v1);
+	if (ret)
+		goto out_unreg_multi_v0;
+
+	ret = xt_register_match(&multiport6_match);
+	if (ret)
+		goto out_unreg_multi_v1;
+
+	ret = xt_register_match(&multiport6_match_v1);
+	if (ret)
+		goto out_unreg_multi6_v0;
+
+	return ret;
+
+out_unreg_multi6_v0:
+	xt_unregister_match(&multiport6_match);
+out_unreg_multi_v1:
+	xt_unregister_match(&multiport_match_v1);
+out_unreg_multi_v0:
+	xt_unregister_match(&multiport_match);
+out:
+	return ret;
+}
+
+static void __exit xt_multiport_fini(void)
+{
+	xt_unregister_match(&multiport_match);
+	xt_unregister_match(&multiport_match_v1);
+	xt_unregister_match(&multiport6_match);
+	xt_unregister_match(&multiport6_match_v1);
+}
+
+module_init(xt_multiport_init);
+module_exit(xt_multiport_fini);