1 /* Kernel module to match one of a list of TCP/UDP ports: ports are in
2 the same place so we can treat them as equal. */
4 /* (C) 1999-2001 Paul `Rusty' Russell
5 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/udp.h>
15 #include <linux/skbuff.h>
17 #include <linux/netfilter_ipv4/ipt_multiport.h>
18 #include <linux/netfilter_ipv4/ip_tables.h>
20 MODULE_LICENSE("GPL");
21 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
22 MODULE_DESCRIPTION("iptables multiple port match module");
25 #define duprintf(format, args...) printk(format , ## args)
27 #define duprintf(format, args...)
30 /* Returns 1 if the port is matched by the test, 0 otherwise. */
32 ports_match(const u_int16_t *portlist, enum ipt_multiport_flags flags,
33 u_int8_t count, u_int16_t src, u_int16_t dst)
36 for (i=0; i<count; i++) {
37 if (flags != IPT_MULTIPORT_DESTINATION
38 && portlist[i] == src)
41 if (flags != IPT_MULTIPORT_SOURCE
42 && portlist[i] == dst)
50 match(const struct sk_buff *skb,
51 const struct net_device *in,
52 const struct net_device *out,
53 const void *matchinfo,
58 const struct ipt_multiport *multiinfo = matchinfo;
60 /* Must not be a fragment. */
64 /* Must be big enough to read ports (both UDP and TCP have
65 them at the start). */
66 pptr = skb_header_pointer(skb, skb->nh.iph->ihl * 4,
67 sizeof(_ports), &_ports[0]);
69 /* We've been asked to examine this packet, and we
70 * can't. Hence, no choice but to drop.
72 duprintf("ipt_multiport:"
73 " Dropping evil offset=0 tinygram.\n");
78 return ports_match(multiinfo->ports,
79 multiinfo->flags, multiinfo->count,
80 ntohs(pptr[0]), ntohs(pptr[1]));
83 /* Called when user tries to insert an entry of this type. */
85 checkentry(const char *tablename,
86 const struct ipt_ip *ip,
88 unsigned int matchsize,
89 unsigned int hook_mask)
91 const struct ipt_multiport *multiinfo = matchinfo;
93 if (matchsize != IPT_ALIGN(sizeof(struct ipt_multiport)))
96 /* Must specify proto == TCP/UDP, no unknown flags or bad count */
97 return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP)
98 && !(ip->invflags & IPT_INV_PROTO)
99 && matchsize == IPT_ALIGN(sizeof(struct ipt_multiport))
100 && (multiinfo->flags == IPT_MULTIPORT_SOURCE
101 || multiinfo->flags == IPT_MULTIPORT_DESTINATION
102 || multiinfo->flags == IPT_MULTIPORT_EITHER)
103 && multiinfo->count <= IPT_MULTI_PORTS;
106 static struct ipt_match multiport_match = {
109 .checkentry = &checkentry,
113 static int __init init(void)
115 return ipt_register_match(&multiport_match);
118 static void __exit fini(void)
120 ipt_unregister_match(&multiport_match);