blob: 03df986217b7b70a63b17000399d6e7a8beba9e9 [file] [log] [blame]
// 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 <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_fib.h>
#include <net/ip_fib.h>
#include <net/route.h>
/* don't try to find route from mcast/bcast/zeronet */
static __be32 get_saddr(__be32 addr)
{
if (ipv4_is_multicast(addr) || ipv4_is_lbcast(addr) ||
ipv4_is_zeronet(addr))
return 0;
return addr;
}
#define DSCP_BITS 0xfc
void nft_fib4_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 *dst = &regs->data[priv->dreg];
const struct net_device *dev = NULL;
struct iphdr *iph, _iph;
__be32 addr;
if (priv->flags & NFTA_FIB_F_IIF)
dev = nft_in(pkt);
else if (priv->flags & NFTA_FIB_F_OIF)
dev = nft_out(pkt);
iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
if (!iph) {
regs->verdict.code = NFT_BREAK;
return;
}
if (priv->flags & NFTA_FIB_F_DADDR)
addr = iph->daddr;
else
addr = iph->saddr;
*dst = inet_dev_addr_type(nft_net(pkt), dev, addr);
}
EXPORT_SYMBOL_GPL(nft_fib4_eval_type);
void nft_fib4_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);
u32 *dest = &regs->data[priv->dreg];
struct iphdr *iph, _iph;
struct fib_result res;
struct flowi4 fl4 = {
.flowi4_scope = RT_SCOPE_UNIVERSE,
.flowi4_iif = LOOPBACK_IFINDEX,
};
const struct net_device *oif;
const struct net_device *found;
/*
* Do not set flowi4_oif, it restricts results (for example, asking
* for oif 3 will get RTN_UNICAST result even if the daddr exits
* on another interface.
*
* Search results for the desired outinterface instead.
*/
if (priv->flags & NFTA_FIB_F_OIF)
oif = nft_out(pkt);
else if (priv->flags & NFTA_FIB_F_IIF)
oif = nft_in(pkt);
else
oif = NULL;
if (nft_hook(pkt) == NF_INET_PRE_ROUTING &&
nft_fib_is_loopback(pkt->skb, nft_in(pkt))) {
nft_fib_store_result(dest, priv, nft_in(pkt));
return;
}
iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
if (!iph) {
regs->verdict.code = NFT_BREAK;
return;
}
if (ipv4_is_zeronet(iph->saddr)) {
if (ipv4_is_lbcast(iph->daddr) ||
ipv4_is_local_multicast(iph->daddr)) {
nft_fib_store_result(dest, priv, pkt->skb->dev);
return;
}
}
if (priv->flags & NFTA_FIB_F_MARK)
fl4.flowi4_mark = pkt->skb->mark;
fl4.flowi4_tos = iph->tos & DSCP_BITS;
if (priv->flags & NFTA_FIB_F_DADDR) {
fl4.daddr = iph->daddr;
fl4.saddr = get_saddr(iph->saddr);
} else {
fl4.daddr = iph->saddr;
fl4.saddr = get_saddr(iph->daddr);
}
*dest = 0;
if (fib_lookup(nft_net(pkt), &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE))
return;
switch (res.type) {
case RTN_UNICAST:
break;
case RTN_LOCAL: /* Should not see RTN_LOCAL here */
return;
default:
break;
}
if (!oif) {
found = FIB_RES_DEV(res);
} else {
if (!fib_info_nh_uses_dev(res.fi, oif))
return;
found = oif;
}
nft_fib_store_result(dest, priv, found);
}
EXPORT_SYMBOL_GPL(nft_fib4_eval);
static struct nft_expr_type nft_fib4_type;
static const struct nft_expr_ops nft_fib4_type_ops = {
.type = &nft_fib4_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
.eval = nft_fib4_eval_type,
.init = nft_fib_init,
.dump = nft_fib_dump,
.validate = nft_fib_validate,
};
static const struct nft_expr_ops nft_fib4_ops = {
.type = &nft_fib4_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
.eval = nft_fib4_eval,
.init = nft_fib_init,
.dump = nft_fib_dump,
.validate = nft_fib_validate,
};
static const struct nft_expr_ops *
nft_fib4_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_fib4_ops;
case NFT_FIB_RESULT_OIFNAME:
return &nft_fib4_ops;
case NFT_FIB_RESULT_ADDRTYPE:
return &nft_fib4_type_ops;
default:
return ERR_PTR(-EOPNOTSUPP);
}
}
static struct nft_expr_type nft_fib4_type __read_mostly = {
.name = "fib",
.select_ops = nft_fib4_select_ops,
.policy = nft_fib_policy,
.maxattr = NFTA_FIB_MAX,
.family = NFPROTO_IPV4,
.owner = THIS_MODULE,
};
static int __init nft_fib4_module_init(void)
{
return nft_register_expr(&nft_fib4_type);
}
static void __exit nft_fib4_module_exit(void)
{
nft_unregister_expr(&nft_fib4_type);
}
module_init(nft_fib4_module_init);
module_exit(nft_fib4_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
MODULE_ALIAS_NFT_AF_EXPR(2, "fib");
MODULE_DESCRIPTION("nftables fib / ip route lookup support");