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// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_fib.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
static int get_ifindex(const struct net_device *dev)
{
return dev ? dev->ifindex : 0;
}
static int nft_fib6_flowi_init(struct flowi6 *fl6, const struct nft_fib *priv,
const struct nft_pktinfo *pkt,
const struct net_device *dev,
struct ipv6hdr *iph)
{
int lookup_flags = 0;
if (priv->flags & NFTA_FIB_F_DADDR) {
fl6->daddr = iph->daddr;
fl6->saddr = iph->saddr;
} else {
if (nft_hook(pkt) == NF_INET_FORWARD &&
priv->flags & NFTA_FIB_F_IIF)
fl6->flowi6_iif = nft_out(pkt)->ifindex;
fl6->daddr = iph->saddr;
fl6->saddr = iph->daddr;
}
if (ipv6_addr_type(&fl6->daddr) & IPV6_ADDR_LINKLOCAL) {
lookup_flags |= RT6_LOOKUP_F_IFACE;
fl6->flowi6_oif = get_ifindex(dev ? dev : pkt->skb->dev);
} else if (priv->flags & NFTA_FIB_F_IIF) {
fl6->flowi6_l3mdev = l3mdev_master_ifindex_rcu(dev);
}
if (ipv6_addr_type(&fl6->saddr) & IPV6_ADDR_UNICAST)
lookup_flags |= RT6_LOOKUP_F_HAS_SADDR;
if (priv->flags & NFTA_FIB_F_MARK)
fl6->flowi6_mark = pkt->skb->mark;
fl6->flowlabel = (*(__be32 *)iph) & IPV6_FLOWINFO_MASK;
return lookup_flags;
}
static u32 __nft_fib6_eval_type(const struct nft_fib *priv,
const struct nft_pktinfo *pkt,
struct ipv6hdr *iph)
{
const struct net_device *dev = NULL;
int route_err, addrtype;
struct rt6_info *rt;
struct flowi6 fl6 = {
.flowi6_iif = LOOPBACK_IFINDEX,
.flowi6_proto = pkt->tprot,
.flowi6_uid = sock_net_uid(nft_net(pkt), NULL),
};
u32 ret = 0;
if (priv->flags & NFTA_FIB_F_IIF)
dev = nft_in(pkt);
else if (priv->flags & NFTA_FIB_F_OIF)
dev = nft_out(pkt);
nft_fib6_flowi_init(&fl6, priv, pkt, dev, iph);
if (dev && nf_ipv6_chk_addr(nft_net(pkt), &fl6.daddr, dev, true))
ret = RTN_LOCAL;
route_err = nf_ip6_route(nft_net(pkt), (struct dst_entry **)&rt,
flowi6_to_flowi(&fl6), false);
if (route_err)
goto err;
if (rt->rt6i_flags & RTF_REJECT) {
route_err = rt->dst.error;
dst_release(&rt->dst);
goto err;
}
if (ipv6_anycast_destination((struct dst_entry *)rt, &fl6.daddr))
ret = RTN_ANYCAST;
else if (!dev && rt->rt6i_flags & RTF_LOCAL)
ret = RTN_LOCAL;
dst_release(&rt->dst);
if (ret)
return ret;
addrtype = ipv6_addr_type(&fl6.daddr);
if (addrtype & IPV6_ADDR_MULTICAST)
return RTN_MULTICAST;
if (addrtype & IPV6_ADDR_UNICAST)
return RTN_UNICAST;
return RTN_UNSPEC;
err:
switch (route_err) {
case -EINVAL:
return RTN_BLACKHOLE;
case -EACCES:
return RTN_PROHIBIT;
case -EAGAIN:
return RTN_THROW;
default:
break;
}
return RTN_UNREACHABLE;
}
void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_fib *priv = nft_expr_priv(expr);
int noff = skb_network_offset(pkt->skb);
u32 *dest = ®s->data[priv->dreg];
struct ipv6hdr *iph, _iph;
iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
if (!iph) {
regs->verdict.code = NFT_BREAK;
return;
}
*dest = __nft_fib6_eval_type(priv, pkt, iph);
}
EXPORT_SYMBOL_GPL(nft_fib6_eval_type);
static bool nft_fib_v6_skip_icmpv6(const struct sk_buff *skb, u8 next, const struct ipv6hdr *iph)
{
if (likely(next != IPPROTO_ICMPV6))
return false;
if (ipv6_addr_type(&iph->saddr) != IPV6_ADDR_ANY)
return false;
return ipv6_addr_type(&iph->daddr) & IPV6_ADDR_LINKLOCAL;
}
void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_fib *priv = nft_expr_priv(expr);
int noff = skb_network_offset(pkt->skb);
const struct net_device *oif = NULL;
u32 *dest = ®s->data[priv->dreg];
struct ipv6hdr *iph, _iph;
struct flowi6 fl6 = {
.flowi6_iif = LOOPBACK_IFINDEX,
.flowi6_proto = pkt->tprot,
.flowi6_uid = sock_net_uid(nft_net(pkt), NULL),
};
struct rt6_info *rt;
int lookup_flags;
if (priv->flags & NFTA_FIB_F_IIF)
oif = nft_in(pkt);
else if (priv->flags & NFTA_FIB_F_OIF)
oif = nft_out(pkt);
iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
if (!iph) {
regs->verdict.code = NFT_BREAK;
return;
}
lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph);
if (nft_hook(pkt) == NF_INET_PRE_ROUTING ||
nft_hook(pkt) == NF_INET_INGRESS) {
if (nft_fib_is_loopback(pkt->skb, nft_in(pkt)) ||
nft_fib_v6_skip_icmpv6(pkt->skb, pkt->tprot, iph)) {
nft_fib_store_result(dest, priv, nft_in(pkt));
return;
}
}
*dest = 0;
rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, pkt->skb,
lookup_flags);
if (rt->dst.error)
goto put_rt_err;
/* Should not see RTF_LOCAL here */
if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL))
goto put_rt_err;
if (oif && oif != rt->rt6i_idev->dev &&
l3mdev_master_ifindex_rcu(rt->rt6i_idev->dev) != oif->ifindex)
goto put_rt_err;
nft_fib_store_result(dest, priv, rt->rt6i_idev->dev);
put_rt_err:
ip6_rt_put(rt);
}
EXPORT_SYMBOL_GPL(nft_fib6_eval);
static struct nft_expr_type nft_fib6_type;
static const struct nft_expr_ops nft_fib6_type_ops = {
.type = &nft_fib6_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
.eval = nft_fib6_eval_type,
.init = nft_fib_init,
.dump = nft_fib_dump,
.validate = nft_fib_validate,
.reduce = nft_fib_reduce,
};
static const struct nft_expr_ops nft_fib6_ops = {
.type = &nft_fib6_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
.eval = nft_fib6_eval,
.init = nft_fib_init,
.dump = nft_fib_dump,
.validate = nft_fib_validate,
.reduce = nft_fib_reduce,
};
static const struct nft_expr_ops *
nft_fib6_select_ops(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
enum nft_fib_result result;
if (!tb[NFTA_FIB_RESULT])
return ERR_PTR(-EINVAL);
result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT]));
switch (result) {
case NFT_FIB_RESULT_OIF:
return &nft_fib6_ops;
case NFT_FIB_RESULT_OIFNAME:
return &nft_fib6_ops;
case NFT_FIB_RESULT_ADDRTYPE:
return &nft_fib6_type_ops;
default:
return ERR_PTR(-EOPNOTSUPP);
}
}
static struct nft_expr_type nft_fib6_type __read_mostly = {
.name = "fib",
.select_ops = nft_fib6_select_ops,
.policy = nft_fib_policy,
.maxattr = NFTA_FIB_MAX,
.family = NFPROTO_IPV6,
.owner = THIS_MODULE,
};
static int __init nft_fib6_module_init(void)
{
return nft_register_expr(&nft_fib6_type);
}
static void __exit nft_fib6_module_exit(void)
{
nft_unregister_expr(&nft_fib6_type);
}
module_init(nft_fib6_module_init);
module_exit(nft_fib6_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
MODULE_ALIAS_NFT_AF_EXPR(10, "fib");
MODULE_DESCRIPTION("nftables fib / ipv6 route lookup support");
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