// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <linux/netfilter_ipv6.h>
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#include <net/netfilter/nf_tables_core.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nft_fib.h>
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#include <net/ip6_fib.h>
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#include <net/ip6_route.h>
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static int get_ifindex(const struct net_device *dev)
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{
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return dev ? dev->ifindex : 0;
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}
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static int nft_fib6_flowi_init(struct flowi6 *fl6, const struct nft_fib *priv,
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const struct nft_pktinfo *pkt,
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const struct net_device *dev,
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struct ipv6hdr *iph)
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{
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int lookup_flags = 0;
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if (priv->flags & NFTA_FIB_F_DADDR) {
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fl6->daddr = iph->daddr;
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fl6->saddr = iph->saddr;
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} else {
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fl6->daddr = iph->saddr;
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fl6->saddr = iph->daddr;
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}
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if (ipv6_addr_type(&fl6->daddr) & IPV6_ADDR_LINKLOCAL) {
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lookup_flags |= RT6_LOOKUP_F_IFACE;
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fl6->flowi6_oif = get_ifindex(dev ? dev : pkt->skb->dev);
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} else if ((priv->flags & NFTA_FIB_F_IIF) &&
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(netif_is_l3_master(dev) || netif_is_l3_slave(dev))) {
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fl6->flowi6_oif = dev->ifindex;
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}
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if (ipv6_addr_type(&fl6->saddr) & IPV6_ADDR_UNICAST)
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lookup_flags |= RT6_LOOKUP_F_HAS_SADDR;
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if (priv->flags & NFTA_FIB_F_MARK)
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fl6->flowi6_mark = pkt->skb->mark;
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fl6->flowlabel = (*(__be32 *)iph) & IPV6_FLOWINFO_MASK;
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return lookup_flags;
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}
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static u32 __nft_fib6_eval_type(const struct nft_fib *priv,
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const struct nft_pktinfo *pkt,
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struct ipv6hdr *iph)
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{
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const struct net_device *dev = NULL;
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int route_err, addrtype;
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struct rt6_info *rt;
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struct flowi6 fl6 = {
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.flowi6_iif = LOOPBACK_IFINDEX,
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.flowi6_proto = pkt->tprot,
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};
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u32 ret = 0;
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if (priv->flags & NFTA_FIB_F_IIF)
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dev = nft_in(pkt);
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else if (priv->flags & NFTA_FIB_F_OIF)
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dev = nft_out(pkt);
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nft_fib6_flowi_init(&fl6, priv, pkt, dev, iph);
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if (dev && nf_ipv6_chk_addr(nft_net(pkt), &fl6.daddr, dev, true))
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ret = RTN_LOCAL;
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route_err = nf_ip6_route(nft_net(pkt), (struct dst_entry **)&rt,
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flowi6_to_flowi(&fl6), false);
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if (route_err)
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goto err;
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if (rt->rt6i_flags & RTF_REJECT) {
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route_err = rt->dst.error;
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dst_release(&rt->dst);
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goto err;
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}
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if (ipv6_anycast_destination((struct dst_entry *)rt, &fl6.daddr))
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ret = RTN_ANYCAST;
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else if (!dev && rt->rt6i_flags & RTF_LOCAL)
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ret = RTN_LOCAL;
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dst_release(&rt->dst);
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if (ret)
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return ret;
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addrtype = ipv6_addr_type(&fl6.daddr);
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if (addrtype & IPV6_ADDR_MULTICAST)
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return RTN_MULTICAST;
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if (addrtype & IPV6_ADDR_UNICAST)
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return RTN_UNICAST;
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return RTN_UNSPEC;
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err:
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switch (route_err) {
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case -EINVAL:
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return RTN_BLACKHOLE;
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case -EACCES:
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return RTN_PROHIBIT;
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case -EAGAIN:
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return RTN_THROW;
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default:
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break;
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}
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return RTN_UNREACHABLE;
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}
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void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_fib *priv = nft_expr_priv(expr);
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int noff = skb_network_offset(pkt->skb);
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u32 *dest = ®s->data[priv->dreg];
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struct ipv6hdr *iph, _iph;
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iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
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if (!iph) {
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regs->verdict.code = NFT_BREAK;
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return;
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}
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*dest = __nft_fib6_eval_type(priv, pkt, iph);
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}
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EXPORT_SYMBOL_GPL(nft_fib6_eval_type);
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static bool nft_fib_v6_skip_icmpv6(const struct sk_buff *skb, u8 next, const struct ipv6hdr *iph)
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{
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if (likely(next != IPPROTO_ICMPV6))
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return false;
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if (ipv6_addr_type(&iph->saddr) != IPV6_ADDR_ANY)
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return false;
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return ipv6_addr_type(&iph->daddr) & IPV6_ADDR_LINKLOCAL;
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}
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void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_fib *priv = nft_expr_priv(expr);
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int noff = skb_network_offset(pkt->skb);
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const struct net_device *oif = NULL;
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u32 *dest = ®s->data[priv->dreg];
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struct ipv6hdr *iph, _iph;
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struct flowi6 fl6 = {
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.flowi6_iif = LOOPBACK_IFINDEX,
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.flowi6_proto = pkt->tprot,
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};
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struct rt6_info *rt;
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int lookup_flags;
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if (priv->flags & NFTA_FIB_F_IIF)
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oif = nft_in(pkt);
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else if (priv->flags & NFTA_FIB_F_OIF)
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oif = nft_out(pkt);
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iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
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if (!iph) {
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regs->verdict.code = NFT_BREAK;
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return;
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}
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lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph);
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if (nft_hook(pkt) == NF_INET_PRE_ROUTING ||
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nft_hook(pkt) == NF_INET_INGRESS) {
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if (nft_fib_is_loopback(pkt->skb, nft_in(pkt)) ||
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nft_fib_v6_skip_icmpv6(pkt->skb, pkt->tprot, iph)) {
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nft_fib_store_result(dest, priv, nft_in(pkt));
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return;
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}
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}
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*dest = 0;
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rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, pkt->skb,
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lookup_flags);
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if (rt->dst.error)
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goto put_rt_err;
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/* Should not see RTF_LOCAL here */
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if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL))
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goto put_rt_err;
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if (oif && oif != rt->rt6i_idev->dev &&
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l3mdev_master_ifindex_rcu(rt->rt6i_idev->dev) != oif->ifindex)
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goto put_rt_err;
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nft_fib_store_result(dest, priv, rt->rt6i_idev->dev);
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put_rt_err:
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ip6_rt_put(rt);
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}
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EXPORT_SYMBOL_GPL(nft_fib6_eval);
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static struct nft_expr_type nft_fib6_type;
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static const struct nft_expr_ops nft_fib6_type_ops = {
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.type = &nft_fib6_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
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.eval = nft_fib6_eval_type,
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.init = nft_fib_init,
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.dump = nft_fib_dump,
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.validate = nft_fib_validate,
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};
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static const struct nft_expr_ops nft_fib6_ops = {
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.type = &nft_fib6_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
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.eval = nft_fib6_eval,
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.init = nft_fib_init,
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.dump = nft_fib_dump,
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.validate = nft_fib_validate,
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};
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static const struct nft_expr_ops *
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nft_fib6_select_ops(const struct nft_ctx *ctx,
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const struct nlattr * const tb[])
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{
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enum nft_fib_result result;
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if (!tb[NFTA_FIB_RESULT])
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return ERR_PTR(-EINVAL);
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result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT]));
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switch (result) {
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case NFT_FIB_RESULT_OIF:
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return &nft_fib6_ops;
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case NFT_FIB_RESULT_OIFNAME:
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return &nft_fib6_ops;
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case NFT_FIB_RESULT_ADDRTYPE:
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return &nft_fib6_type_ops;
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default:
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return ERR_PTR(-EOPNOTSUPP);
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}
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}
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static struct nft_expr_type nft_fib6_type __read_mostly = {
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.name = "fib",
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.select_ops = nft_fib6_select_ops,
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.policy = nft_fib_policy,
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.maxattr = NFTA_FIB_MAX,
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.family = NFPROTO_IPV6,
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.owner = THIS_MODULE,
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};
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static int __init nft_fib6_module_init(void)
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{
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return nft_register_expr(&nft_fib6_type);
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}
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static void __exit nft_fib6_module_exit(void)
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{
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nft_unregister_expr(&nft_fib6_type);
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}
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module_init(nft_fib6_module_init);
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module_exit(nft_fib6_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
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MODULE_ALIAS_NFT_AF_EXPR(10, "fib");
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MODULE_DESCRIPTION("nftables fib / ipv6 route lookup support");
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