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/*
* xt_ipvs - kernel module to match IPVS connection properties
*
* Author: Hannes Eder <heder@google.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#ifdef CONFIG_IP_VS_IPV6
#include <net/ipv6.h>
#endif
#include <linux/ip_vs.h>
#include <linux/types.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_ipvs.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/ip_vs.h>
MODULE_AUTHOR("Hannes Eder <heder@google.com>");
MODULE_DESCRIPTION("Xtables: match IPVS connection properties");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_ipvs");
MODULE_ALIAS("ip6t_ipvs");
/* borrowed from xt_conntrack */
static bool ipvs_mt_addrcmp(const union nf_inet_addr *kaddr,
const union nf_inet_addr *uaddr,
const union nf_inet_addr *umask,
unsigned int l3proto)
{
if (l3proto == NFPROTO_IPV4)
return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
#ifdef CONFIG_IP_VS_IPV6
else if (l3proto == NFPROTO_IPV6)
return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
&uaddr->in6) == 0;
#endif
else
return false;
}
static bool
ipvs_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct xt_ipvs_mtinfo *data = par->matchinfo;
/* ipvs_mt_check ensures that family is only NFPROTO_IPV[46]. */
const u_int8_t family = par->family;
struct ip_vs_iphdr iph;
struct ip_vs_protocol *pp;
struct ip_vs_conn *cp;
bool match = true;
if (data->bitmask == XT_IPVS_IPVS_PROPERTY) {
match = skb->ipvs_property ^
!!(data->invert & XT_IPVS_IPVS_PROPERTY);
goto out;
}
/* other flags than XT_IPVS_IPVS_PROPERTY are set */
if (!skb->ipvs_property) {
match = false;
goto out;
}
ip_vs_fill_iphdr(family, skb_network_header(skb), &iph);
if (data->bitmask & XT_IPVS_PROTO)
if ((iph.protocol == data->l4proto) ^
!(data->invert & XT_IPVS_PROTO)) {
match = false;
goto out;
}
pp = ip_vs_proto_get(iph.protocol);
if (unlikely(!pp)) {
match = false;
goto out;
}
/*
* Check if the packet belongs to an existing entry
*/
cp = pp->conn_out_get(family, skb, &iph, iph.len, 1 /* inverse */);
if (unlikely(cp == NULL)) {
match = false;
goto out;
}
/*
* We found a connection, i.e. ct != 0, make sure to call
* __ip_vs_conn_put before returning. In our case jump to out_put_con.
*/
if (data->bitmask & XT_IPVS_VPORT)
if ((cp->vport == data->vport) ^
!(data->invert & XT_IPVS_VPORT)) {
match = false;
goto out_put_cp;
}
if (data->bitmask & XT_IPVS_VPORTCTL)
if ((cp->control != NULL &&
cp->control->vport == data->vportctl) ^
!(data->invert & XT_IPVS_VPORTCTL)) {
match = false;
goto out_put_cp;
}
if (data->bitmask & XT_IPVS_DIR) {
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL || nf_ct_is_untracked(ct)) {
match = false;
goto out_put_cp;
}
if ((ctinfo >= IP_CT_IS_REPLY) ^
!!(data->invert & XT_IPVS_DIR)) {
match = false;
goto out_put_cp;
}
}
if (data->bitmask & XT_IPVS_METHOD)
if (((cp->flags & IP_VS_CONN_F_FWD_MASK) == data->fwd_method) ^
!(data->invert & XT_IPVS_METHOD)) {
match = false;
goto out_put_cp;
}
if (data->bitmask & XT_IPVS_VADDR) {
if (ipvs_mt_addrcmp(&cp->vaddr, &data->vaddr,
&data->vmask, family) ^
!(data->invert & XT_IPVS_VADDR)) {
match = false;
goto out_put_cp;
}
}
out_put_cp:
__ip_vs_conn_put(cp);
out:
pr_debug("match=%d\n", match);
return match;
}
static int ipvs_mt_check(const struct xt_mtchk_param *par)
{
if (par->family != NFPROTO_IPV4
#ifdef CONFIG_IP_VS_IPV6
&& par->family != NFPROTO_IPV6
#endif
) {
pr_info("protocol family %u not supported\n", par->family);
return -EINVAL;
}
return 0;
}
static struct xt_match xt_ipvs_mt_reg __read_mostly = {
.name = "ipvs",
.revision = 0,
.family = NFPROTO_UNSPEC,
.match = ipvs_mt,
.checkentry = ipvs_mt_check,
.matchsize = XT_ALIGN(sizeof(struct xt_ipvs_mtinfo)),
.me = THIS_MODULE,
};
static int __init ipvs_mt_init(void)
{
return xt_register_match(&xt_ipvs_mt_reg);
}
static void __exit ipvs_mt_exit(void)
{
xt_unregister_match(&xt_ipvs_mt_reg);
}
module_init(ipvs_mt_init);
module_exit(ipvs_mt_exit);
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