patch-2.3.99-pre2 linux/net/ipv4/netfilter/ipt_multiport.c

• Lines: 103
• Date: Fri Mar 17 10:56:20 2000
• Orig file: v2.3.99-pre1/linux/net/ipv4/netfilter/ipt_multiport.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.99-pre1/linux/net/ipv4/netfilter/ipt_multiport.c linux/net/ipv4/netfilter/ipt_multiport.c
@@ -0,0 +1,102 @@
+/* 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. */
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/udp.h>
+#include <linux/skbuff.h>
+
+#include <linux/netfilter_ipv4/ipt_multiport.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+#if 0
+#define duprintf(format, args...) printk(format , ## args)
+#else
+#define duprintf(format, args...)
+#endif
+
+EXPORT_NO_SYMBOLS;
+
+/* Returns 1 if the port is matched by the test, 0 otherwise. */
+static inline int
+ports_match(const u_int16_t *portlist, enum ipt_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 != IPT_MULTIPORT_DESTINATION
+		    && portlist[i] == src)
+			return 1;
+
+		if (flags != IPT_MULTIPORT_SOURCE
+		    && portlist[i] == dst)
+			return 1;
+	}
+
+	return 0;
+}
+
+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 udphdr *udp = hdr;
+	const struct ipt_multiport *multiinfo = matchinfo;
+
+	/* Must be big enough to read ports. */
+	if (offset == 0 && datalen < sizeof(struct udphdr)) {
+		/* We've been asked to examine this packet, and we
+		   can't.  Hence, no choice but to drop. */
+			duprintf("ipt_multiport:"
+				 " Dropping evil offset=0 tinygram.\n");
+			*hotdrop = 1;
+			return 0;
+	}
+
+	/* Must not be a fragment. */
+	return !offset
+		&& ports_match(multiinfo->ports,
+			       multiinfo->flags, multiinfo->count,
+			       ntohs(udp->source), ntohs(udp->dest));
+}
+
+/* Called when user tries to insert an entry of this type. */
+static int
+checkentry(const char *tablename,
+	   const struct ipt_ip *ip,
+	   void *matchinfo,
+	   unsigned int matchsize,
+	   unsigned int hook_mask)
+{
+	const struct ipt_multiport *multiinfo = matchinfo;
+
+	/* Must specify proto == TCP/UDP, no unknown flags or bad count */
+	return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP)
+		&& !(ip->flags & IPT_INV_PROTO)
+		&& matchsize == IPT_ALIGN(sizeof(struct ipt_multiport))
+		&& (multiinfo->flags == IPT_MULTIPORT_SOURCE
+		    || multiinfo->flags == IPT_MULTIPORT_DESTINATION
+		    || multiinfo->flags == IPT_MULTIPORT_EITHER)
+		&& multiinfo->count <= IPT_MULTI_PORTS;
+}
+
+static struct ipt_match multiport_match
+= { { NULL, NULL }, "multiport", &match, &checkentry, THIS_MODULE };
+
+static int __init init(void)
+{
+	return ipt_register_match(&multiport_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&multiport_match);
+}
+
+module_init(init);
+module_exit(fini);