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/* 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_ipv6/ip6t_multiport.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("ip6tables match for multiple ports");
#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 ip6t_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 != IP6T_MULTIPORT_DESTINATION
&& portlist[i] == src)
return 1;
if (flags != IP6T_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 struct xt_match *match,
const void *matchinfo,
int offset,
unsigned int protoff,
int *hotdrop)
{
u16 _ports[2], *pptr;
const struct ip6t_multiport *multiinfo = matchinfo;
/* Must not be a fragment. */
if (offset)
return 0;
/* Must be big enough to read ports (both UDP and TCP have
them at the start). */
pptr = skb_header_pointer(skb, protoff, sizeof(_ports), &_ports[0]);
if (pptr == NULL) {
/* We've been asked to examine this packet, and we
* can't. Hence, no choice but to drop.
*/
duprintf("ip6t_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]));
}
/* 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 ip6t_ip6 *ip = info;
const struct ip6t_multiport *multiinfo = matchinfo;
/* Must specify proto == TCP/UDP, no unknown flags or bad count */
return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP)
&& !(ip->invflags & IP6T_INV_PROTO)
&& (multiinfo->flags == IP6T_MULTIPORT_SOURCE
|| multiinfo->flags == IP6T_MULTIPORT_DESTINATION
|| multiinfo->flags == IP6T_MULTIPORT_EITHER)
&& multiinfo->count <= IP6T_MULTI_PORTS;
}
static struct ip6t_match multiport_match = {
.name = "multiport",
.match = match,
.matchsize = sizeof(struct ip6t_multiport),
.checkentry = checkentry,
.me = THIS_MODULE,
};
static int __init ip6t_multiport_init(void)
{
return ip6t_register_match(&multiport_match);
}
static void __exit ip6t_multiport_fini(void)
{
ip6t_unregister_match(&multiport_match);
}
module_init(ip6t_multiport_init);
module_exit(ip6t_multiport_fini);
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