Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | /*
* 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/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_ip.h>
#include <linux/ip.h>
#include <net/ip.h>
#include <linux/in.h>
#include <linux/module.h>
struct tcpudphdr {
__be16 src;
__be16 dst;
};
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)
{
const struct ebt_ip_info *info = data;
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 EBT_NOMATCH;
if (info->bitmask & EBT_IP_TOS &&
FWINV(info->tos != ih->tos, EBT_IP_TOS))
return EBT_NOMATCH;
if (info->bitmask & EBT_IP_SOURCE &&
FWINV((ih->saddr & info->smsk) !=
info->saddr, EBT_IP_SOURCE))
return EBT_NOMATCH;
if ((info->bitmask & EBT_IP_DEST) &&
FWINV((ih->daddr & info->dmsk) !=
info->daddr, EBT_IP_DEST))
return EBT_NOMATCH;
if (info->bitmask & EBT_IP_PROTO) {
if (FWINV(info->protocol != ih->protocol, EBT_IP_PROTO))
return EBT_NOMATCH;
if (!(info->bitmask & EBT_IP_DPORT) &&
!(info->bitmask & EBT_IP_SPORT))
return EBT_MATCH;
if (ntohs(ih->frag_off) & IP_OFFSET)
return EBT_NOMATCH;
pptr = skb_header_pointer(skb, ih->ihl*4,
sizeof(_ports), &_ports);
if (pptr == NULL)
return EBT_NOMATCH;
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 EBT_NOMATCH;
}
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 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)
{
const struct ebt_ip_info *info = data;
if (datalen != EBT_ALIGN(sizeof(struct ebt_ip_info)))
return -EINVAL;
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 ebt_match filter_ip __read_mostly = {
.name = EBT_IP_MATCH,
.match = ebt_filter_ip,
.check = ebt_ip_check,
.me = THIS_MODULE,
};
static int __init ebt_ip_init(void)
{
return ebt_register_match(&filter_ip);
}
static void __exit ebt_ip_fini(void)
{
ebt_unregister_match(&filter_ip);
}
module_init(ebt_ip_init);
module_exit(ebt_ip_fini);
MODULE_DESCRIPTION("Ebtables: IPv4 protocol packet match");
MODULE_LICENSE("GPL");
|