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/*
* ebt_ip
*
* Authors:
* Bart De Schuymer <bdschuym@pandora.be>
*
* April, 2002
*
* Changes:
* added ip-sport and ip-dport
* Innominate Security Technologies AG <mhopf@innominate.com>
* September, 2002
*/
#include <linux/ip.h>
#include <net/ip.h>
#include <linux/in.h>
#include <linux/module.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_ip.h>
struct tcpudphdr {
__be16 src;
__be16 dst;
};
static bool
ebt_ip_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct ebt_ip_info *info = par->matchinfo;
const struct iphdr *ih;
struct iphdr _iph;
const struct tcpudphdr *pptr;
struct tcpudphdr _ports;
ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
if (ih == NULL)
return false;
if (info->bitmask & EBT_IP_TOS &&
FWINV(info->tos != ih->tos, EBT_IP_TOS))
return false;
if (info->bitmask & EBT_IP_SOURCE &&
FWINV((ih->saddr & info->smsk) !=
info->saddr, EBT_IP_SOURCE))
return false;
if ((info->bitmask & EBT_IP_DEST) &&
FWINV((ih->daddr & info->dmsk) !=
info->daddr, EBT_IP_DEST))
return false;
if (info->bitmask & EBT_IP_PROTO) {
if (FWINV(info->protocol != ih->protocol, EBT_IP_PROTO))
return false;
if (!(info->bitmask & EBT_IP_DPORT) &&
!(info->bitmask & EBT_IP_SPORT))
return true;
if (ntohs(ih->frag_off) & IP_OFFSET)
return false;
pptr = skb_header_pointer(skb, ih->ihl*4,
sizeof(_ports), &_ports);
if (pptr == NULL)
return false;
if (info->bitmask & EBT_IP_DPORT) {
u32 dst = ntohs(pptr->dst);
if (FWINV(dst < info->dport[0] ||
dst > info->dport[1],
EBT_IP_DPORT))
return false;
}
if (info->bitmask & EBT_IP_SPORT) {
u32 src = ntohs(pptr->src);
if (FWINV(src < info->sport[0] ||
src > info->sport[1],
EBT_IP_SPORT))
return false;
}
}
return true;
}
static int ebt_ip_mt_check(const struct xt_mtchk_param *par)
{
const struct ebt_ip_info *info = par->matchinfo;
const struct ebt_entry *e = par->entryinfo;
if (e->ethproto != 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->invflags & EBT_IP_PROTO)
return -EINVAL;
if (info->protocol != IPPROTO_TCP &&
info->protocol != IPPROTO_UDP &&
info->protocol != IPPROTO_UDPLITE &&
info->protocol != IPPROTO_SCTP &&
info->protocol != IPPROTO_DCCP)
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 xt_match ebt_ip_mt_reg __read_mostly = {
.name = "ip",
.revision = 0,
.family = NFPROTO_BRIDGE,
.match = ebt_ip_mt,
.checkentry = ebt_ip_mt_check,
.matchsize = sizeof(struct ebt_ip_info),
.me = THIS_MODULE,
};
static int __init ebt_ip_init(void)
{
return xt_register_match(&ebt_ip_mt_reg);
}
static void __exit ebt_ip_fini(void)
{
xt_unregister_match(&ebt_ip_mt_reg);
}
module_init(ebt_ip_init);
module_exit(ebt_ip_fini);
MODULE_DESCRIPTION("Ebtables: IPv4 protocol packet match");
MODULE_LICENSE("GPL");
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