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/* Kernel module to match an IP address pool. */
#include <linux/module.h>
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ip_pool.h>
#include <linux/netfilter_ipv4/ipt_pool.h>
static inline int match_pool(
ip_pool_t index,
__u32 addr,
int inv
) {
if (ip_pool_match(index, ntohl(addr)))
inv = !inv;
return inv;
}
static int match(
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop
) {
const struct ipt_pool_info *info = matchinfo;
const struct iphdr *iph = skb->nh.iph;
if (info->src != IP_POOL_NONE && !match_pool(info->src, iph->saddr,
info->flags&IPT_POOL_INV_SRC))
return 0;
if (info->dst != IP_POOL_NONE && !match_pool(info->dst, iph->daddr,
info->flags&IPT_POOL_INV_DST))
return 0;
return 1;
}
static int checkentry(
const char *tablename,
const struct ipt_ip *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask
) {
if (matchsize != IPT_ALIGN(sizeof(struct ipt_pool_info)))
return 0;
return 1;
}
static struct ipt_match pool_match
= { { NULL, NULL }, "pool", &match, &checkentry, NULL, THIS_MODULE };
static int __init init(void)
{
return ipt_register_match(&pool_match);
}
static void __exit fini(void)
{
ipt_unregister_match(&pool_match);
}
module_init(init);
module_exit(fini);
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