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/* Kernel module to match one of a list of TCP/UDP(-Lite)/SCTP/DCCP 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("Xtables: multiple port matching for TCP, UDP, UDP-Lite, SCTP and DCCP");
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 bool
ports_match_v0(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 true;
if (flags != XT_MULTIPORT_SOURCE && portlist[i] == dst)
return true;
}
return false;
}
/* Returns 1 if the port is matched by the test, 0 otherwise. */
static inline bool
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 true ^ minfo->invert;
if (minfo->flags == XT_MULTIPORT_DESTINATION
&& dst >= s && dst <= e)
return true ^ minfo->invert;
if (minfo->flags == XT_MULTIPORT_EITHER
&& ((dst >= s && dst <= e)
|| (src >= s && src <= e)))
return true ^ minfo->invert;
} else {
/* exact port matching */
duprintf("src or dst matches with %d?\n", s);
if (minfo->flags == XT_MULTIPORT_SOURCE
&& src == s)
return true ^ minfo->invert;
if (minfo->flags == XT_MULTIPORT_DESTINATION
&& dst == s)
return true ^ minfo->invert;
if (minfo->flags == XT_MULTIPORT_EITHER
&& (src == s || dst == s))
return true ^ minfo->invert;
}
}
return minfo->invert;
}
static bool
multiport_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
{
const __be16 *pptr;
__be16 _ports[2];
const struct xt_multiport *multiinfo = par->matchinfo;
if (par->fragoff != 0)
return false;
pptr = skb_header_pointer(skb, par->thoff, 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");
*par->hotdrop = true;
return false;
}
return ports_match_v0(multiinfo->ports, multiinfo->flags,
multiinfo->count, ntohs(pptr[0]), ntohs(pptr[1]));
}
static bool
multiport_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
const __be16 *pptr;
__be16 _ports[2];
const struct xt_multiport_v1 *multiinfo = par->matchinfo;
if (par->fragoff != 0)
return false;
pptr = skb_header_pointer(skb, par->thoff, 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");
*par->hotdrop = true;
return false;
}
return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1]));
}
static inline bool
check(u_int16_t proto,
u_int8_t ip_invflags,
u_int8_t match_flags,
u_int8_t count)
{
/* Must specify supported protocol, no unknown flags or bad count */
return (proto == IPPROTO_TCP || proto == IPPROTO_UDP
|| proto == IPPROTO_UDPLITE
|| proto == IPPROTO_SCTP || proto == IPPROTO_DCCP)
&& !(ip_invflags & XT_INV_PROTO)
&& (match_flags == XT_MULTIPORT_SOURCE
|| match_flags == XT_MULTIPORT_DESTINATION
|| match_flags == XT_MULTIPORT_EITHER)
&& count <= XT_MULTI_PORTS;
}
static bool multiport_mt_check_v0(const struct xt_mtchk_param *par)
{
const struct ipt_ip *ip = par->entryinfo;
const struct xt_multiport *multiinfo = par->matchinfo;
return check(ip->proto, ip->invflags, multiinfo->flags,
multiinfo->count);
}
static bool multiport_mt_check(const struct xt_mtchk_param *par)
{
const struct ipt_ip *ip = par->entryinfo;
const struct xt_multiport_v1 *multiinfo = par->matchinfo;
return check(ip->proto, ip->invflags, multiinfo->flags,
multiinfo->count);
}
static bool multiport_mt6_check_v0(const struct xt_mtchk_param *par)
{
const struct ip6t_ip6 *ip = par->entryinfo;
const struct xt_multiport *multiinfo = par->matchinfo;
return check(ip->proto, ip->invflags, multiinfo->flags,
multiinfo->count);
}
static bool multiport_mt6_check(const struct xt_mtchk_param *par)
{
const struct ip6t_ip6 *ip = par->entryinfo;
const struct xt_multiport_v1 *multiinfo = par->matchinfo;
return check(ip->proto, ip->invflags, multiinfo->flags,
multiinfo->count);
}
static struct xt_match multiport_mt_reg[] __read_mostly = {
{
.name = "multiport",
.family = NFPROTO_IPV4,
.revision = 0,
.checkentry = multiport_mt_check_v0,
.match = multiport_mt_v0,
.matchsize = sizeof(struct xt_multiport),
.me = THIS_MODULE,
},
{
.name = "multiport",
.family = NFPROTO_IPV4,
.revision = 1,
.checkentry = multiport_mt_check,
.match = multiport_mt,
.matchsize = sizeof(struct xt_multiport_v1),
.me = THIS_MODULE,
},
{
.name = "multiport",
.family = NFPROTO_IPV6,
.revision = 0,
.checkentry = multiport_mt6_check_v0,
.match = multiport_mt_v0,
.matchsize = sizeof(struct xt_multiport),
.me = THIS_MODULE,
},
{
.name = "multiport",
.family = NFPROTO_IPV6,
.revision = 1,
.checkentry = multiport_mt6_check,
.match = multiport_mt,
.matchsize = sizeof(struct xt_multiport_v1),
.me = THIS_MODULE,
},
};
static int __init multiport_mt_init(void)
{
return xt_register_matches(multiport_mt_reg,
ARRAY_SIZE(multiport_mt_reg));
}
static void __exit multiport_mt_exit(void)
{
xt_unregister_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg));
}
module_init(multiport_mt_init);
module_exit(multiport_mt_exit);
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