+#if IS_ENABLED(CONFIG_INET)
+static struct net_device *inet_fib_lookup_dev(struct net *net,
+ const void *addr)
+{
+ struct net_device *dev;
+ struct rtable *rt;
+ struct in_addr daddr;
+
+ memcpy(&daddr, addr, sizeof(struct in_addr));
+ rt = ip_route_output(net, daddr.s_addr, 0, 0, 0);
+ if (IS_ERR(rt))
+ return ERR_CAST(rt);
+
+ dev = rt->dst.dev;
+ dev_hold(dev);
+
+ ip_rt_put(rt);
+
+ return dev;
+}
+#else
+static struct net_device *inet_fib_lookup_dev(struct net *net,
+ const void *addr)
+{
+ return ERR_PTR(-EAFNOSUPPORT);
+}
+#endif
+
+#if IS_ENABLED(CONFIG_IPV6)
+static struct net_device *inet6_fib_lookup_dev(struct net *net,
+ const void *addr)
+{
+ struct net_device *dev;
+ struct dst_entry *dst;
+ struct flowi6 fl6;
+ int err;
+
+ if (!ipv6_stub)
+ return ERR_PTR(-EAFNOSUPPORT);
+
+ memset(&fl6, 0, sizeof(fl6));
+ memcpy(&fl6.daddr, addr, sizeof(struct in6_addr));
+ err = ipv6_stub->ipv6_dst_lookup(net, NULL, &dst, &fl6);
+ if (err)
+ return ERR_PTR(err);
+
+ dev = dst->dev;
+ dev_hold(dev);
+ dst_release(dst);
+
+ return dev;
+}
+#else
+static struct net_device *inet6_fib_lookup_dev(struct net *net,
+ const void *addr)
+{
+ return ERR_PTR(-EAFNOSUPPORT);
+}
+#endif
+
+static struct net_device *find_outdev(struct net *net,
+ struct mpls_route *rt,
+ struct mpls_nh *nh, int oif)
+{
+ struct net_device *dev = NULL;
+
+ if (!oif) {
+ switch (nh->nh_via_table) {
+ case NEIGH_ARP_TABLE:
+ dev = inet_fib_lookup_dev(net, mpls_nh_via(rt, nh));
+ break;
+ case NEIGH_ND_TABLE:
+ dev = inet6_fib_lookup_dev(net, mpls_nh_via(rt, nh));
+ break;
+ case NEIGH_LINK_TABLE:
+ break;
+ }
+ } else {
+ dev = dev_get_by_index(net, oif);
+ }
+
+ if (!dev)
+ return ERR_PTR(-ENODEV);
+
+ if (IS_ERR(dev))
+ return dev;
+
+ /* The caller is holding rtnl anyways, so release the dev reference */
+ dev_put(dev);
+
+ return dev;
+}
+
+static int mpls_nh_assign_dev(struct net *net, struct mpls_route *rt,
+ struct mpls_nh *nh, int oif)
+{
+ struct net_device *dev = NULL;
+ int err = -ENODEV;
+
+ dev = find_outdev(net, rt, nh, oif);
+ if (IS_ERR(dev)) {
+ err = PTR_ERR(dev);
+ dev = NULL;
+ goto errout;
+ }
+
+ /* Ensure this is a supported device */
+ err = -EINVAL;
+ if (!mpls_dev_get(dev))
+ goto errout;
+
+ if ((nh->nh_via_table == NEIGH_LINK_TABLE) &&
+ (dev->addr_len != nh->nh_via_alen))
+ goto errout;
+
+ RCU_INIT_POINTER(nh->nh_dev, dev);
+
+ return 0;
+
+errout:
+ return err;
+}
+
+static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
+ struct mpls_route *rt)
+{
+ struct net *net = cfg->rc_nlinfo.nl_net;
+ struct mpls_nh *nh = rt->rt_nh;
+ int err;
+ int i;
+
+ if (!nh)
+ return -ENOMEM;
+
+ err = -EINVAL;
+ /* Ensure only a supported number of labels are present */
+ if (cfg->rc_output_labels > MAX_NEW_LABELS)
+ goto errout;
+
+ nh->nh_labels = cfg->rc_output_labels;
+ for (i = 0; i < nh->nh_labels; i++)
+ nh->nh_label[i] = cfg->rc_output_label[i];
+
+ nh->nh_via_table = cfg->rc_via_table;
+ memcpy(__mpls_nh_via(rt, nh), cfg->rc_via, cfg->rc_via_alen);
+ nh->nh_via_alen = cfg->rc_via_alen;
+
+ err = mpls_nh_assign_dev(net, rt, nh, cfg->rc_ifindex);
+ if (err)
+ goto errout;
+
+ return 0;
+
+errout:
+ return err;
+}
+
+static int mpls_nh_build(struct net *net, struct mpls_route *rt,
+ struct mpls_nh *nh, int oif,
+ struct nlattr *via, struct nlattr *newdst)
+{
+ int err = -ENOMEM;
+
+ if (!nh)
+ goto errout;
+
+ if (newdst) {
+ err = nla_get_labels(newdst, MAX_NEW_LABELS,
+ &nh->nh_labels, nh->nh_label);
+ if (err)
+ goto errout;
+ }
+
+ if (via) {
+ err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
+ __mpls_nh_via(rt, nh));
+ if (err)
+ goto errout;
+ } else {
+ nh->nh_via_table = MPLS_NEIGH_TABLE_UNSPEC;
+ }
+
+ err = mpls_nh_assign_dev(net, rt, nh, oif);
+ if (err)
+ goto errout;
+
+ return 0;
+
+errout:
+ return err;
+}
+
+static int mpls_count_nexthops(struct rtnexthop *rtnh, int len,
+ u8 cfg_via_alen, u8 *max_via_alen)
+{
+ int nhs = 0;
+ int remaining = len;
+
+ if (!rtnh) {
+ *max_via_alen = cfg_via_alen;
+ return 1;
+ }
+
+ *max_via_alen = 0;
+
+ while (rtnh_ok(rtnh, remaining)) {
+ struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
+ int attrlen;
+
+ attrlen = rtnh_attrlen(rtnh);
+ nla = nla_find(attrs, attrlen, RTA_VIA);
+ if (nla && nla_len(nla) >=
+ offsetof(struct rtvia, rtvia_addr)) {
+ int via_alen = nla_len(nla) -
+ offsetof(struct rtvia, rtvia_addr);
+
+ if (via_alen <= MAX_VIA_ALEN)
+ *max_via_alen = max_t(u16, *max_via_alen,
+ via_alen);
+ }
+
+ nhs++;
+ rtnh = rtnh_next(rtnh, &remaining);
+ }
+
+ /* leftover implies invalid nexthop configuration, discard it */
+ return remaining > 0 ? 0 : nhs;
+}
+
+static int mpls_nh_build_multi(struct mpls_route_config *cfg,
+ struct mpls_route *rt)
+{
+ struct rtnexthop *rtnh = cfg->rc_mp;
+ struct nlattr *nla_via, *nla_newdst;
+ int remaining = cfg->rc_mp_len;
+ int nhs = 0;
+ int err = 0;
+
+ change_nexthops(rt) {
+ int attrlen;
+
+ nla_via = NULL;
+ nla_newdst = NULL;
+
+ err = -EINVAL;
+ if (!rtnh_ok(rtnh, remaining))
+ goto errout;
+
+ /* neither weighted multipath nor any flags
+ * are supported
+ */
+ if (rtnh->rtnh_hops || rtnh->rtnh_flags)
+ goto errout;
+
+ attrlen = rtnh_attrlen(rtnh);
+ if (attrlen > 0) {
+ struct nlattr *attrs = rtnh_attrs(rtnh);
+
+ nla_via = nla_find(attrs, attrlen, RTA_VIA);
+ nla_newdst = nla_find(attrs, attrlen, RTA_NEWDST);
+ }
+
+ err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh,
+ rtnh->rtnh_ifindex, nla_via,
+ nla_newdst);
+ if (err)
+ goto errout;
+
+ rtnh = rtnh_next(rtnh, &remaining);
+ nhs++;
+ } endfor_nexthops(rt);
+
+ rt->rt_nhn = nhs;
+
+ return 0;
+
+errout:
+ return err;
+}
+