1 files changed, 283 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/nft_fib_ipv6.c b/net/ipv6/netfilter/nft_fib_ipv6.c
new file mode 100644
index 000000000..36dc14b34
--- /dev/null
+++ b/net/ipv6/netfilter/nft_fib_ipv6.c
@@ -0,0 +1,283 @@
+// 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 = &regs->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 = &regs->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");