2011-08-19 05:52:40 -06:00
|
|
|
/*
|
|
|
|
* Copyright (c) 2011 Florian Westphal <fw@strlen.de>
|
|
|
|
*
|
|
|
|
* This program is free software; you can redistribute it and/or modify
|
|
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
|
|
* published by the Free Software Foundation.
|
|
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/module.h>
|
|
|
|
#include <linux/skbuff.h>
|
|
|
|
#include <linux/netdevice.h>
|
|
|
|
#include <linux/route.h>
|
|
|
|
#include <net/ip6_fib.h>
|
|
|
|
#include <net/ip6_route.h>
|
|
|
|
|
|
|
|
#include <linux/netfilter/xt_rpfilter.h>
|
|
|
|
#include <linux/netfilter/x_tables.h>
|
|
|
|
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
|
|
|
|
MODULE_DESCRIPTION("Xtables: IPv6 reverse path filter match");
|
|
|
|
|
|
|
|
static bool rpfilter_addr_unicast(const struct in6_addr *addr)
|
|
|
|
{
|
|
|
|
int addr_type = ipv6_addr_type(addr);
|
|
|
|
return addr_type & IPV6_ADDR_UNICAST;
|
|
|
|
}
|
|
|
|
|
2015-09-18 13:32:59 -06:00
|
|
|
static bool rpfilter_lookup_reverse6(struct net *net, const struct sk_buff *skb,
|
2011-08-19 05:52:40 -06:00
|
|
|
const struct net_device *dev, u8 flags)
|
|
|
|
{
|
|
|
|
struct rt6_info *rt;
|
|
|
|
struct ipv6hdr *iph = ipv6_hdr(skb);
|
|
|
|
bool ret = false;
|
|
|
|
struct flowi6 fl6 = {
|
2014-04-28 01:51:56 -06:00
|
|
|
.flowi6_iif = LOOPBACK_IFINDEX,
|
2011-08-19 05:52:40 -06:00
|
|
|
.flowlabel = (* (__be32 *) iph) & IPV6_FLOWINFO_MASK,
|
|
|
|
.flowi6_proto = iph->nexthdr,
|
|
|
|
.daddr = iph->saddr,
|
|
|
|
};
|
|
|
|
int lookup_flags;
|
|
|
|
|
|
|
|
if (rpfilter_addr_unicast(&iph->daddr)) {
|
|
|
|
memcpy(&fl6.saddr, &iph->daddr, sizeof(struct in6_addr));
|
|
|
|
lookup_flags = RT6_LOOKUP_F_HAS_SADDR;
|
|
|
|
} else {
|
|
|
|
lookup_flags = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
fl6.flowi6_mark = flags & XT_RPFILTER_VALID_MARK ? skb->mark : 0;
|
|
|
|
if ((flags & XT_RPFILTER_LOOSE) == 0) {
|
|
|
|
fl6.flowi6_oif = dev->ifindex;
|
|
|
|
lookup_flags |= RT6_LOOKUP_F_IFACE;
|
|
|
|
}
|
|
|
|
|
2015-09-18 13:32:59 -06:00
|
|
|
rt = (void *) ip6_route_lookup(net, &fl6, lookup_flags);
|
2011-08-19 05:52:40 -06:00
|
|
|
if (rt->dst.error)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (rt->rt6i_flags & (RTF_REJECT|RTF_ANYCAST))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (rt->rt6i_flags & RTF_LOCAL) {
|
|
|
|
ret = flags & XT_RPFILTER_ACCEPT_LOCAL;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (rt->rt6i_idev->dev == dev || (flags & XT_RPFILTER_LOOSE))
|
|
|
|
ret = true;
|
|
|
|
out:
|
2012-10-28 18:13:19 -06:00
|
|
|
ip6_rt_put(rt);
|
2011-08-19 05:52:40 -06:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2013-04-17 16:45:24 -06:00
|
|
|
static bool rpfilter_is_local(const struct sk_buff *skb)
|
|
|
|
{
|
|
|
|
const struct rt6_info *rt = (const void *) skb_dst(skb);
|
|
|
|
return rt && (rt->rt6i_flags & RTF_LOCAL);
|
|
|
|
}
|
|
|
|
|
2011-08-19 05:52:40 -06:00
|
|
|
static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par)
|
|
|
|
{
|
|
|
|
const struct xt_rpfilter_info *info = par->matchinfo;
|
|
|
|
int saddrtype;
|
|
|
|
struct ipv6hdr *iph;
|
|
|
|
bool invert = info->flags & XT_RPFILTER_INVERT;
|
|
|
|
|
2013-04-17 16:45:24 -06:00
|
|
|
if (rpfilter_is_local(skb))
|
2011-08-19 05:52:40 -06:00
|
|
|
return true ^ invert;
|
|
|
|
|
|
|
|
iph = ipv6_hdr(skb);
|
|
|
|
saddrtype = ipv6_addr_type(&iph->saddr);
|
|
|
|
if (unlikely(saddrtype == IPV6_ADDR_ANY))
|
|
|
|
return true ^ invert; /* not routable: forward path will drop it */
|
|
|
|
|
2015-09-18 13:32:59 -06:00
|
|
|
return rpfilter_lookup_reverse6(par->net, skb, par->in, info->flags) ^ invert;
|
2011-08-19 05:52:40 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
static int rpfilter_check(const struct xt_mtchk_param *par)
|
|
|
|
{
|
|
|
|
const struct xt_rpfilter_info *info = par->matchinfo;
|
|
|
|
unsigned int options = ~XT_RPFILTER_OPTION_MASK;
|
|
|
|
|
|
|
|
if (info->flags & options) {
|
|
|
|
pr_info("unknown options encountered");
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (strcmp(par->table, "mangle") != 0 &&
|
|
|
|
strcmp(par->table, "raw") != 0) {
|
|
|
|
pr_info("match only valid in the \'raw\' "
|
|
|
|
"or \'mangle\' tables, not \'%s\'.\n", par->table);
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct xt_match rpfilter_mt_reg __read_mostly = {
|
|
|
|
.name = "rpfilter",
|
|
|
|
.family = NFPROTO_IPV6,
|
|
|
|
.checkentry = rpfilter_check,
|
|
|
|
.match = rpfilter_mt,
|
|
|
|
.matchsize = sizeof(struct xt_rpfilter_info),
|
|
|
|
.hooks = (1 << NF_INET_PRE_ROUTING),
|
|
|
|
.me = THIS_MODULE
|
|
|
|
};
|
|
|
|
|
|
|
|
static int __init rpfilter_mt_init(void)
|
|
|
|
{
|
|
|
|
return xt_register_match(&rpfilter_mt_reg);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void __exit rpfilter_mt_exit(void)
|
|
|
|
{
|
|
|
|
xt_unregister_match(&rpfilter_mt_reg);
|
|
|
|
}
|
|
|
|
|
|
|
|
module_init(rpfilter_mt_init);
|
|
|
|
module_exit(rpfilter_mt_exit);
|