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/*
* ebt_ip
*
* Authors:
* Bart De Schuymer <bart.de.schuymer@pandora.be>
*
* April, 2002
*
* Changes:
* added ip-sport and ip-dport
* Innominate Security Technologies AG <mhopf@innominate.com>
* September, 2002
*/
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_ip.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/module.h>
struct tcpudphdr {
uint16_t src;
uint16_t dst;
};
union h_u {
unsigned char *raw;
struct tcpudphdr *tuh;
};
static int ebt_filter_ip(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const void *data,
unsigned int datalen)
{
struct ebt_ip_info *info = (struct ebt_ip_info *)data;
if (info->bitmask & EBT_IP_TOS &&
FWINV(info->tos != ((*skb).nh.iph)->tos, EBT_IP_TOS))
return EBT_NOMATCH;
if (info->bitmask & EBT_IP_PROTO) {
if (FWINV(info->protocol != ((*skb).nh.iph)->protocol,
EBT_IP_PROTO))
return EBT_NOMATCH;
if ( info->protocol == IPPROTO_TCP ||
info->protocol == IPPROTO_UDP )
{
union h_u h;
h.raw = skb->data + skb->nh.iph->ihl*4;
if (info->bitmask & EBT_IP_DPORT) {
uint16_t port = ntohs(h.tuh->dst);
if (FWINV(port < info->dport[0] ||
port > info->dport[1],
EBT_IP_DPORT))
return EBT_NOMATCH;
}
if (info->bitmask & EBT_IP_SPORT) {
uint16_t port = ntohs(h.tuh->src);
if (FWINV(port < info->sport[0] ||
port > info->sport[1],
EBT_IP_SPORT))
return EBT_NOMATCH;
}
}
}
if (info->bitmask & EBT_IP_SOURCE &&
FWINV((((*skb).nh.iph)->saddr & info->smsk) !=
info->saddr, EBT_IP_SOURCE))
return EBT_NOMATCH;
if ((info->bitmask & EBT_IP_DEST) &&
FWINV((((*skb).nh.iph)->daddr & info->dmsk) !=
info->daddr, EBT_IP_DEST))
return EBT_NOMATCH;
return EBT_MATCH;
}
static int ebt_ip_check(const char *tablename, unsigned int hookmask,
const struct ebt_entry *e, void *data, unsigned int datalen)
{
struct ebt_ip_info *info = (struct ebt_ip_info *)data;
if (datalen != sizeof(struct ebt_ip_info))
return -EINVAL;
if (e->ethproto != __constant_htons(ETH_P_IP) ||
e->invflags & EBT_IPROTO)
return -EINVAL;
if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK)
return -EINVAL;
if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) {
if (!info->bitmask & EBT_IPROTO)
return -EINVAL;
if (info->protocol != IPPROTO_TCP &&
info->protocol != IPPROTO_UDP)
return -EINVAL;
}
if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1])
return -EINVAL;
if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1])
return -EINVAL;
return 0;
}
static struct ebt_match filter_ip =
{
{NULL, NULL}, EBT_IP_MATCH, ebt_filter_ip, ebt_ip_check, NULL,
THIS_MODULE
};
static int __init init(void)
{
return ebt_register_match(&filter_ip);
}
static void __exit fini(void)
{
ebt_unregister_match(&filter_ip);
}
module_init(init);
module_exit(fini);
EXPORT_NO_SYMBOLS;
MODULE_LICENSE("GPL");
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