3 files changed, 559 insertions, 153 deletions

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index bb185a28de98..c70d750148b6 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -19,36 +19,13 @@
 #include <net/ipv6.h>
 #include <net/addrconf.h>
 #endif
+#include <net/nexthop.h>
 #include "internal.h"
 
-#define LABEL_NOT_SPECIFIED (1<<20)
-#define MAX_NEW_LABELS 2
-
-/* This maximum ha length copied from the definition of struct neighbour */
-#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))
-
-enum mpls_payload_type {
-	MPT_UNSPEC, /* IPv4 or IPv6 */
-	MPT_IPV4 = 4,
-	MPT_IPV6 = 6,
-
-	/* Other types not implemented:
-	 *  - Pseudo-wire with or without control word (RFC4385)
-	 *  - GAL (RFC5586)
-	 */
-};
-
-struct mpls_route { /* next hop label forwarding entry */
-	struct net_device __rcu *rt_dev;
-	struct rcu_head		rt_rcu;
-	u32			rt_label[MAX_NEW_LABELS];
-	u8			rt_protocol; /* routing protocol that set this entry */
-	u8                      rt_payload_type;
-	u8			rt_labels;
-	u8			rt_via_alen;
-	u8			rt_via_table;
-	u8			rt_via[0];
-};
+/* Maximum number of labels to look ahead at when selecting a path of
+ * a multipath route
+ */
+#define MAX_MP_SELECT_LABELS 4
 
 static int zero = 0;
 static int label_limit = (1 << 20) - 1;
@@ -80,10 +57,24 @@ bool mpls_output_possible(const struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(mpls_output_possible);
 
-static unsigned int mpls_rt_header_size(const struct mpls_route *rt)
+static u8 *__mpls_nh_via(struct mpls_route *rt, struct mpls_nh *nh)
+{
+	u8 *nh0_via = PTR_ALIGN((u8 *)&rt->rt_nh[rt->rt_nhn], VIA_ALEN_ALIGN);
+	int nh_index = nh - rt->rt_nh;
+
+	return nh0_via + rt->rt_max_alen * nh_index;
+}
+
+static const u8 *mpls_nh_via(const struct mpls_route *rt,
+			     const struct mpls_nh *nh)
+{
+	return __mpls_nh_via((struct mpls_route *)rt, (struct mpls_nh *)nh);
+}
+
+static unsigned int mpls_nh_header_size(const struct mpls_nh *nh)
 {
 	/* The size of the layer 2.5 labels to be added for this route */
-	return rt->rt_labels * sizeof(struct mpls_shim_hdr);
+	return nh->nh_labels * sizeof(struct mpls_shim_hdr);
 }
 
 unsigned int mpls_dev_mtu(const struct net_device *dev)
@@ -105,6 +96,80 @@ bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 }
 EXPORT_SYMBOL_GPL(mpls_pkt_too_big);
 
+static struct mpls_nh *mpls_select_multipath(struct mpls_route *rt,
+					     struct sk_buff *skb, bool bos)
+{
+	struct mpls_entry_decoded dec;
+	struct mpls_shim_hdr *hdr;
+	bool eli_seen = false;
+	int label_index;
+	int nh_index = 0;
+	u32 hash = 0;
+
+	/* No need to look further into packet if there's only
+	 * one path
+	 */
+	if (rt->rt_nhn == 1)
+		goto out;
+
+	for (label_index = 0; label_index < MAX_MP_SELECT_LABELS && !bos;
+	     label_index++) {
+		if (!pskb_may_pull(skb, sizeof(*hdr) * label_index))
+			break;
+
+		/* Read and decode the current label */
+		hdr = mpls_hdr(skb) + label_index;
+		dec = mpls_entry_decode(hdr);
+
+		/* RFC6790 - reserved labels MUST NOT be used as keys
+		 * for the load-balancing function
+		 */
+		if (likely(dec.label >= MPLS_LABEL_FIRST_UNRESERVED)) {
+			hash = jhash_1word(dec.label, hash);
+
+			/* The entropy label follows the entropy label
+			 * indicator, so this means that the entropy
+			 * label was just added to the hash - no need to
+			 * go any deeper either in the label stack or in the
+			 * payload
+			 */
+			if (eli_seen)
+				break;
+		} else if (dec.label == MPLS_LABEL_ENTROPY) {
+			eli_seen = true;
+		}
+
+		bos = dec.bos;
+		if (bos && pskb_may_pull(skb, sizeof(*hdr) * label_index +
+					 sizeof(struct iphdr))) {
+			const struct iphdr *v4hdr;
+
+			v4hdr = (const struct iphdr *)(mpls_hdr(skb) +
+						       label_index);
+			if (v4hdr->version == 4) {
+				hash = jhash_3words(ntohl(v4hdr->saddr),
+						    ntohl(v4hdr->daddr),
+						    v4hdr->protocol, hash);
+			} else if (v4hdr->version == 6 &&
+				pskb_may_pull(skb, sizeof(*hdr) * label_index +
+					      sizeof(struct ipv6hdr))) {
+				const struct ipv6hdr *v6hdr;
+
+				v6hdr = (const struct ipv6hdr *)(mpls_hdr(skb) +
+								label_index);
+
+				hash = __ipv6_addr_jhash(&v6hdr->saddr, hash);
+				hash = __ipv6_addr_jhash(&v6hdr->daddr, hash);
+				hash = jhash_1word(v6hdr->nexthdr, hash);
+			}
+		}
+	}
+
+	nh_index = hash % rt->rt_nhn;
+out:
+	return &rt->rt_nh[nh_index];
+}
+
 static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
 			struct mpls_entry_decoded dec)
 {
@@ -159,6 +224,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 	struct net *net = dev_net(dev);
 	struct mpls_shim_hdr *hdr;
 	struct mpls_route *rt;
+	struct mpls_nh *nh;
 	struct mpls_entry_decoded dec;
 	struct net_device *out_dev;
 	struct mpls_dev *mdev;
@@ -196,8 +262,12 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 	if (!rt)
 		goto drop;
 
+	nh = mpls_select_multipath(rt, skb, dec.bos);
+	if (!nh)
+		goto drop;
+
 	/* Find the output device */
-	out_dev = rcu_dereference(rt->rt_dev);
+	out_dev = rcu_dereference(nh->nh_dev);
 	if (!mpls_output_possible(out_dev))
 		goto drop;
 
@@ -212,7 +282,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 	dec.ttl -= 1;
 
 	/* Verify the destination can hold the packet */
-	new_header_size = mpls_rt_header_size(rt);
+	new_header_size = mpls_nh_header_size(nh);
 	mtu = mpls_dev_mtu(out_dev);
 	if (mpls_pkt_too_big(skb, mtu - new_header_size))
 		goto drop;
@@ -240,13 +310,14 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 		/* Push the new labels */
 		hdr = mpls_hdr(skb);
 		bos = dec.bos;
-		for (i = rt->rt_labels - 1; i >= 0; i--) {
-			hdr[i] = mpls_entry_encode(rt->rt_label[i], dec.ttl, 0, bos);
+		for (i = nh->nh_labels - 1; i >= 0; i--) {
+			hdr[i] = mpls_entry_encode(nh->nh_label[i],
+						   dec.ttl, 0, bos);
 			bos = false;
 		}
 	}
 
-	err = neigh_xmit(rt->rt_via_table, out_dev, rt->rt_via, skb);
+	err = neigh_xmit(nh->nh_via_table, out_dev, mpls_nh_via(rt, nh), skb);
 	if (err)
 		net_dbg_ratelimited("%s: packet transmission failed: %d\n",
 				    __func__, err);
@@ -270,24 +341,33 @@ static const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = {
 struct mpls_route_config {
 	u32			rc_protocol;
 	u32			rc_ifindex;
-	u16			rc_via_table;
-	u16			rc_via_alen;
+	u8			rc_via_table;
+	u8			rc_via_alen;
 	u8			rc_via[MAX_VIA_ALEN];
 	u32			rc_label;
-	u32			rc_output_labels;
+	u8			rc_output_labels;
 	u32			rc_output_label[MAX_NEW_LABELS];
 	u32			rc_nlflags;
 	enum mpls_payload_type	rc_payload_type;
 	struct nl_info		rc_nlinfo;
+	struct rtnexthop	*rc_mp;
+	int			rc_mp_len;
 };
 
-static struct mpls_route *mpls_rt_alloc(size_t alen)
+static struct mpls_route *mpls_rt_alloc(int num_nh, u8 max_alen)
 {
+	u8 max_alen_aligned = ALIGN(max_alen, VIA_ALEN_ALIGN);
 	struct mpls_route *rt;
 
-	rt = kzalloc(sizeof(*rt) + alen, GFP_KERNEL);
-	if (rt)
-		rt->rt_via_alen = alen;
+	rt = kzalloc(ALIGN(sizeof(*rt) + num_nh * sizeof(*rt->rt_nh),
+			   VIA_ALEN_ALIGN) +
+		     num_nh * max_alen_aligned,
+		     GFP_KERNEL);
+	if (rt) {
+		rt->rt_nhn = num_nh;
+		rt->rt_max_alen = max_alen_aligned;
+	}
+
 	return rt;
 }
 
@@ -312,25 +392,22 @@ static void mpls_notify_route(struct net *net, unsigned index,
 }
 
 static void mpls_route_update(struct net *net, unsigned index,
-			      struct net_device *dev, struct mpls_route *new,
+			      struct mpls_route *new,
 			      const struct nl_info *info)
 {
 	struct mpls_route __rcu **platform_label;
-	struct mpls_route *rt, *old = NULL;
+	struct mpls_route *rt;
 
 	ASSERT_RTNL();
 
 	platform_label = rtnl_dereference(net->mpls.platform_label);
 	rt = rtnl_dereference(platform_label[index]);
-	if (!dev || (rt && (rtnl_dereference(rt->rt_dev) == dev))) {
-		rcu_assign_pointer(platform_label[index], new);
-		old = rt;
-	}
+	rcu_assign_pointer(platform_label[index], new);
 
-	mpls_notify_route(net, index, old, new, info);
+	mpls_notify_route(net, index, rt, new, info);
 
 	/* If we removed a route free it now */
-	mpls_rt_free(old);
+	mpls_rt_free(rt);
 }
 
 static unsigned find_free_label(struct net *net)
@@ -350,7 +427,8 @@ static unsigned find_free_label(struct net *net)
 }
 
 #if IS_ENABLED(CONFIG_INET)
-static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
+static struct net_device *inet_fib_lookup_dev(struct net *net,
+					      const void *addr)
 {
 	struct net_device *dev;
 	struct rtable *rt;
@@ -369,14 +447,16 @@ static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
 	return dev;
 }
 #else
-static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
+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, void *addr)
+static struct net_device *inet6_fib_lookup_dev(struct net *net,
+					       const void *addr)
 {
 	struct net_device *dev;
 	struct dst_entry *dst;
@@ -399,47 +479,234 @@ static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
 	return dev;
 }
 #else
-static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
+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_config *cfg)
+				      struct mpls_route *rt,
+				      struct mpls_nh *nh, int oif)
 {
 	struct net_device *dev = NULL;
 
-	if (!cfg->rc_ifindex) {
-		switch (cfg->rc_via_table) {
+	if (!oif) {
+		switch (nh->nh_via_table) {
 		case NEIGH_ARP_TABLE:
-			dev = inet_fib_lookup_dev(net, cfg->rc_via);
+			dev = inet_fib_lookup_dev(net, mpls_nh_via(rt, nh));
 			break;
 		case NEIGH_ND_TABLE:
-			dev = inet6_fib_lookup_dev(net, cfg->rc_via);
+			dev = inet6_fib_lookup_dev(net, mpls_nh_via(rt, nh));
 			break;
 		case NEIGH_LINK_TABLE:
 			break;
 		}
 	} else {
-		dev = dev_get_by_index(net, cfg->rc_ifindex);
+		dev = dev_get_by_index(net, oif);
 	}
 
 	if (!dev)
 		return ERR_PTR(-ENODEV);
 
+	/* 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;
+
+	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;
+	}
+
+	err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
+			  __mpls_nh_via(rt, nh));
+	if (err)
+		goto errout;
+
+	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);
+		}
+
+		if (!nla_via)
+			goto errout;
+
+		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;
+}
+
 static int mpls_route_add(struct mpls_route_config *cfg)
 {
 	struct mpls_route __rcu **platform_label;
 	struct net *net = cfg->rc_nlinfo.nl_net;
-	struct net_device *dev = NULL;
 	struct mpls_route *rt, *old;
-	unsigned index;
-	int i;
 	int err = -EINVAL;
+	u8 max_via_alen;
+	unsigned index;
+	int nhs;
 
 	index = cfg->rc_label;
 
@@ -457,27 +724,6 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 	if (index >= net->mpls.platform_labels)
 		goto errout;
 
-	/* Ensure only a supported number of labels are present */
-	if (cfg->rc_output_labels > MAX_NEW_LABELS)
-		goto errout;
-
-	dev = find_outdev(net, cfg);
-	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;
-
-	err = -EINVAL;
-	if ((cfg->rc_via_table == NEIGH_LINK_TABLE) &&
-	    (dev->addr_len != cfg->rc_via_alen))
-		goto errout;
-
 	/* Append makes no sense with mpls */
 	err = -EOPNOTSUPP;
 	if (cfg->rc_nlflags & NLM_F_APPEND)
@@ -497,28 +743,34 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 	if (!(cfg->rc_nlflags & NLM_F_CREATE) && !old)
 		goto errout;
 
+	err = -EINVAL;
+	nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len,
+				  cfg->rc_via_alen, &max_via_alen);
+	if (nhs == 0)
+		goto errout;
+
 	err = -ENOMEM;
-	rt = mpls_rt_alloc(cfg->rc_via_alen);
+	rt = mpls_rt_alloc(nhs, max_via_alen);
 	if (!rt)
 		goto errout;
 
-	rt->rt_labels = cfg->rc_output_labels;
-	for (i = 0; i < rt->rt_labels; i++)
-		rt->rt_label[i] = cfg->rc_output_label[i];
 	rt->rt_protocol = cfg->rc_protocol;
-	RCU_INIT_POINTER(rt->rt_dev, dev);
 	rt->rt_payload_type = cfg->rc_payload_type;
-	rt->rt_via_table = cfg->rc_via_table;
-	memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen);
 
-	mpls_route_update(net, index, NULL, rt, &cfg->rc_nlinfo);
+	if (cfg->rc_mp)
+		err = mpls_nh_build_multi(cfg, rt);
+	else
+		err = mpls_nh_build_from_cfg(cfg, rt);
+	if (err)
+		goto freert;
+
+	mpls_route_update(net, index, rt, &cfg->rc_nlinfo);
 
-	dev_put(dev);
 	return 0;
 
+freert:
+	mpls_rt_free(rt);
 errout:
-	if (dev)
-		dev_put(dev);
 	return err;
 }
 
@@ -538,7 +790,7 @@ static int mpls_route_del(struct mpls_route_config *cfg)
 	if (index >= net->mpls.platform_labels)
 		goto errout;
 
-	mpls_route_update(net, index, NULL, NULL, &cfg->rc_nlinfo);
+	mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
 
 	err = 0;
 errout:
@@ -635,9 +887,11 @@ static void mpls_ifdown(struct net_device *dev)
 		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
 		if (!rt)
 			continue;
-		if (rtnl_dereference(rt->rt_dev) != dev)
-			continue;
-		rt->rt_dev = NULL;
+		for_nexthops(rt) {
+			if (rtnl_dereference(nh->nh_dev) != dev)
+				continue;
+			nh->nh_dev = NULL;
+		} endfor_nexthops(rt);
 	}
 
 	mdev = mpls_dev_get(dev);
@@ -736,7 +990,7 @@ int nla_put_labels(struct sk_buff *skb, int attrtype,
 EXPORT_SYMBOL_GPL(nla_put_labels);
 
 int nla_get_labels(const struct nlattr *nla,
-		   u32 max_labels, u32 *labels, u32 label[])
+		   u32 max_labels, u8 *labels, u32 label[])
 {
 	unsigned len = nla_len(nla);
 	unsigned nla_labels;
@@ -781,6 +1035,48 @@ int nla_get_labels(const struct nlattr *nla,
 }
 EXPORT_SYMBOL_GPL(nla_get_labels);
 
+int nla_get_via(const struct nlattr *nla, u8 *via_alen,
+		u8 *via_table, u8 via_addr[])
+{
+	struct rtvia *via = nla_data(nla);
+	int err = -EINVAL;
+	int alen;
+
+	if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
+		goto errout;
+	alen = nla_len(nla) -
+			offsetof(struct rtvia, rtvia_addr);
+	if (alen > MAX_VIA_ALEN)
+		goto errout;
+
+	/* Validate the address family */
+	switch (via->rtvia_family) {
+	case AF_PACKET:
+		*via_table = NEIGH_LINK_TABLE;
+		break;
+	case AF_INET:
+		*via_table = NEIGH_ARP_TABLE;
+		if (alen != 4)
+			goto errout;
+		break;
+	case AF_INET6:
+		*via_table = NEIGH_ND_TABLE;
+		if (alen != 16)
+			goto errout;
+		break;
+	default:
+		/* Unsupported address family */
+		goto errout;
+	}
+
+	memcpy(via_addr, via->rtvia_addr, alen);
+	*via_alen = alen;
+	err = 0;
+
+errout:
+	return err;
+}
+
 static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 			       struct mpls_route_config *cfg)
 {
@@ -844,7 +1140,7 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 			break;
 		case RTA_DST:
 		{
-			u32 label_count;
+			u8 label_count;
 			if (nla_get_labels(nla, 1, &label_count,
 					   &cfg->rc_label))
 				goto errout;
@@ -857,35 +1153,15 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 		}
 		case RTA_VIA:
 		{
-			struct rtvia *via = nla_data(nla);
-			if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
-				goto errout;
-			cfg->rc_via_alen   = nla_len(nla) -
-				offsetof(struct rtvia, rtvia_addr);
-			if (cfg->rc_via_alen > MAX_VIA_ALEN)
+			if (nla_get_via(nla, &cfg->rc_via_alen,
+					&cfg->rc_via_table, cfg->rc_via))
 				goto errout;
-
-			/* Validate the address family */
-			switch(via->rtvia_family) {
-			case AF_PACKET:
-				cfg->rc_via_table = NEIGH_LINK_TABLE;
-				break;
-			case AF_INET:
-				cfg->rc_via_table = NEIGH_ARP_TABLE;
-				if (cfg->rc_via_alen != 4)
-					goto errout;
-				break;
-			case AF_INET6:
-				cfg->rc_via_table = NEIGH_ND_TABLE;
-				if (cfg->rc_via_alen != 16)
-					goto errout;
-				break;
-			default:
-				/* Unsupported address family */
-				goto errout;
-			}
-
-			memcpy(cfg->rc_via, via->rtvia_addr, cfg->rc_via_alen);
+			break;
+		}
+		case RTA_MULTIPATH:
+		{
+			cfg->rc_mp = nla_data(nla);
+			cfg->rc_mp_len = nla_len(nla);
 			break;
 		}
 		default:
@@ -946,16 +1222,52 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
 	rtm->rtm_type = RTN_UNICAST;
 	rtm->rtm_flags = 0;
 
-	if (rt->rt_labels &&
-	    nla_put_labels(skb, RTA_NEWDST, rt->rt_labels, rt->rt_label))
-		goto nla_put_failure;
-	if (nla_put_via(skb, rt->rt_via_table, rt->rt_via, rt->rt_via_alen))
-		goto nla_put_failure;
-	dev = rtnl_dereference(rt->rt_dev);
-	if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
-		goto nla_put_failure;
 	if (nla_put_labels(skb, RTA_DST, 1, &label))
 		goto nla_put_failure;
+	if (rt->rt_nhn == 1) {
+		const struct mpls_nh *nh = rt->rt_nh;
+
+		if (nh->nh_labels &&
+		    nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
+				   nh->nh_label))
+			goto nla_put_failure;
+		if (nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh),
+				nh->nh_via_alen))
+			goto nla_put_failure;
+		dev = rtnl_dereference(nh->nh_dev);
+		if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
+			goto nla_put_failure;
+	} else {
+		struct rtnexthop *rtnh;
+		struct nlattr *mp;
+
+		mp = nla_nest_start(skb, RTA_MULTIPATH);
+		if (!mp)
+			goto nla_put_failure;
+
+		for_nexthops(rt) {
+			rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
+			if (!rtnh)
+				goto nla_put_failure;
+
+			dev = rtnl_dereference(nh->nh_dev);
+			if (dev)
+				rtnh->rtnh_ifindex = dev->ifindex;
+			if (nh->nh_labels && nla_put_labels(skb, RTA_NEWDST,
+							    nh->nh_labels,
+							    nh->nh_label))
+				goto nla_put_failure;
+			if (nla_put_via(skb, nh->nh_via_table,
+					mpls_nh_via(rt, nh),
+					nh->nh_via_alen))
+				goto nla_put_failure;
+
+			/* length of rtnetlink header + attributes */
+			rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
+		} endfor_nexthops(rt);
+
+		nla_nest_end(skb, mp);
+	}
 
 	nlmsg_end(skb, nlh);
 	return 0;
@@ -1000,12 +1312,30 @@ static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
 {
 	size_t payload =
 		NLMSG_ALIGN(sizeof(struct rtmsg))
-		+ nla_total_size(2 + rt->rt_via_alen)	/* RTA_VIA */
 		+ nla_total_size(4);			/* RTA_DST */
-	if (rt->rt_labels)				/* RTA_NEWDST */
-		payload += nla_total_size(rt->rt_labels * 4);
-	if (rt->rt_dev)					/* RTA_OIF */
-		payload += nla_total_size(4);
+
+	if (rt->rt_nhn == 1) {
+		struct mpls_nh *nh = rt->rt_nh;
+
+		if (nh->nh_dev)
+			payload += nla_total_size(4); /* RTA_OIF */
+		payload += nla_total_size(2 + nh->nh_via_alen); /* RTA_VIA */
+		if (nh->nh_labels) /* RTA_NEWDST */
+			payload += nla_total_size(nh->nh_labels * 4);
+	} else {
+		/* each nexthop is packed in an attribute */
+		size_t nhsize = 0;
+
+		for_nexthops(rt) {
+			nhsize += nla_total_size(sizeof(struct rtnexthop));
+			nhsize += nla_total_size(2 + nh->nh_via_alen);
+			if (nh->nh_labels)
+				nhsize += nla_total_size(nh->nh_labels * 4);
+		} endfor_nexthops(rt);
+		/* nested attribute */
+		payload += nla_total_size(nhsize);
+	}
+
 	return payload;
 }
 
@@ -1057,25 +1387,29 @@ static int resize_platform_label_table(struct net *net, size_t limit)
 	/* In case the predefined labels need to be populated */
 	if (limit > MPLS_LABEL_IPV4NULL) {
 		struct net_device *lo = net->loopback_dev;
-		rt0 = mpls_rt_alloc(lo->addr_len);
+		rt0 = mpls_rt_alloc(1, lo->addr_len);
 		if (!rt0)
 			goto nort0;
-		RCU_INIT_POINTER(rt0->rt_dev, lo);
+		RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo);
 		rt0->rt_protocol = RTPROT_KERNEL;
 		rt0->rt_payload_type = MPT_IPV4;
-		rt0->rt_via_table = NEIGH_LINK_TABLE;
-		memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
+		rt0->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
+		rt0->rt_nh->nh_via_alen = lo->addr_len;
+		memcpy(__mpls_nh_via(rt0, rt0->rt_nh), lo->dev_addr,
+		       lo->addr_len);
 	}
 	if (limit > MPLS_LABEL_IPV6NULL) {
 		struct net_device *lo = net->loopback_dev;
-		rt2 = mpls_rt_alloc(lo->addr_len);
+		rt2 = mpls_rt_alloc(1, lo->addr_len);
 		if (!rt2)
 			goto nort2;
-		RCU_INIT_POINTER(rt2->rt_dev, lo);
+		RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo);
 		rt2->rt_protocol = RTPROT_KERNEL;
 		rt2->rt_payload_type = MPT_IPV6;
-		rt2->rt_via_table = NEIGH_LINK_TABLE;
-		memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
+		rt2->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
+		rt2->rt_nh->nh_via_alen = lo->addr_len;
+		memcpy(__mpls_nh_via(rt2, rt2->rt_nh), lo->dev_addr,
+		       lo->addr_len);
 	}
 
 	rtnl_lock();
@@ -1085,7 +1419,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
 
 	/* Free any labels beyond the new table */
 	for (index = limit; index < old_limit; index++)
-		mpls_route_update(net, index, NULL, NULL, NULL);
+		mpls_route_update(net, index, NULL, NULL);
 
 	/* Copy over the old labels */
 	cp_size = size;
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index 2681a4ba6c37..bde52ce88c94 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -21,6 +21,76 @@ struct mpls_dev {
 
 struct sk_buff;
 
+#define LABEL_NOT_SPECIFIED (1 << 20)
+#define MAX_NEW_LABELS 2
+
+/* This maximum ha length copied from the definition of struct neighbour */
+#define VIA_ALEN_ALIGN sizeof(unsigned long)
+#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, VIA_ALEN_ALIGN))
+
+enum mpls_payload_type {
+	MPT_UNSPEC, /* IPv4 or IPv6 */
+	MPT_IPV4 = 4,
+	MPT_IPV6 = 6,
+
+	/* Other types not implemented:
+	 *  - Pseudo-wire with or without control word (RFC4385)
+	 *  - GAL (RFC5586)
+	 */
+};
+
+struct mpls_nh { /* next hop label forwarding entry */
+	struct net_device __rcu *nh_dev;
+	u32			nh_label[MAX_NEW_LABELS];
+	u8			nh_labels;
+	u8			nh_via_alen;
+	u8			nh_via_table;
+};
+
+/* The route, nexthops and vias are stored together in the same memory
+ * block:
+ *
+ * +----------------------+
+ * | mpls_route           |
+ * +----------------------+
+ * | mpls_nh 0            |
+ * +----------------------+
+ * | ...                  |
+ * +----------------------+
+ * | mpls_nh n-1          |
+ * +----------------------+
+ * | alignment padding    |
+ * +----------------------+
+ * | via[rt_max_alen] 0   |
+ * +----------------------+
+ * | ...                  |
+ * +----------------------+
+ * | via[rt_max_alen] n-1 |
+ * +----------------------+
+ */
+struct mpls_route { /* next hop label forwarding entry */
+	struct rcu_head		rt_rcu;
+	u8			rt_protocol;
+	u8			rt_payload_type;
+	u8			rt_max_alen;
+	unsigned int		rt_nhn;
+	struct mpls_nh		rt_nh[0];
+};
+
+#define for_nexthops(rt) {						\
+	int nhsel; struct mpls_nh *nh;			\
+	for (nhsel = 0, nh = (rt)->rt_nh;				\
+	     nhsel < (rt)->rt_nhn;					\
+	     nh++, nhsel++)
+
+#define change_nexthops(rt) {						\
+	int nhsel; struct mpls_nh *nh;				\
+	for (nhsel = 0,	nh = (struct mpls_nh *)((rt)->rt_nh);	\
+	     nhsel < (rt)->rt_nhn;					\
+	     nh++, nhsel++)
+
+#define endfor_nexthops(rt) }
+
 static inline struct mpls_shim_hdr *mpls_hdr(const struct sk_buff *skb)
 {
 	return (struct mpls_shim_hdr *)skb_network_header(skb);
@@ -52,8 +122,10 @@ static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr *
 
 int nla_put_labels(struct sk_buff *skb, int attrtype,  u8 labels,
 		   const u32 label[]);
-int nla_get_labels(const struct nlattr *nla, u32 max_labels, u32 *labels,
+int nla_get_labels(const struct nlattr *nla, u32 max_labels, u8 *labels,
 		   u32 label[]);
+int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
+		u8 via[]);
 bool mpls_output_possible(const struct net_device *dev);
 unsigned int mpls_dev_mtu(const struct net_device *dev);
 bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu);
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index 21e70bc9af98..67591aef9cae 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -37,7 +37,7 @@ static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
 	return en->labels * sizeof(struct mpls_shim_hdr);
 }
 
-int mpls_output(struct sock *sk, struct sk_buff *skb)
+int mpls_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	struct mpls_iptunnel_encap *tun_encap_info;
 	struct mpls_shim_hdr *hdr;