Merge branch 'mpls-fixes'

Robert Shearman says:

====================
mpls: fixes for nexthops without via addresses

These four fixes all apply to the case of having an mpls route with an
output device, but without a nexthop.

Patches 2 and 3 could really have been combined in one patch, but I
wanted to separate the fix for some recent breakage from the fix for a
day-1 issue.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/mpls/af_mpls.c

@@ -27,6 +27,8 @@
  */
 #define MAX_MP_SELECT_LABELS 4
 
+#define MPLS_NEIGH_TABLE_UNSPEC (NEIGH_LINK_TABLE + 1)
+
 static int zero = 0;
 static int label_limit = (1 << 20) - 1;
 
@@ -317,7 +319,13 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 		}
 	}
 
-	err = neigh_xmit(nh->nh_via_table, out_dev, mpls_nh_via(rt, nh), skb);
+	/* If via wasn't specified then send out using device address */
+	if (nh->nh_via_table == MPLS_NEIGH_TABLE_UNSPEC)
+		err = neigh_xmit(NEIGH_LINK_TABLE, out_dev,
+				 out_dev->dev_addr, skb);
+	else
+		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);
@@ -534,6 +542,10 @@ static int mpls_nh_assign_dev(struct net *net, struct mpls_route *rt,
 	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;
@@ -592,10 +604,14 @@ static int mpls_nh_build(struct net *net, struct mpls_route *rt,
 			goto errout;
 	}
 
-	err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
-			  __mpls_nh_via(rt, nh));
-	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)
@@ -677,9 +693,6 @@ static int mpls_nh_build_multi(struct mpls_route_config *cfg,
 			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);
@@ -1118,6 +1131,7 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 
 	cfg->rc_label		= LABEL_NOT_SPECIFIED;
 	cfg->rc_protocol	= rtm->rtm_protocol;
+	cfg->rc_via_table	= MPLS_NEIGH_TABLE_UNSPEC;
 	cfg->rc_nlflags		= nlh->nlmsg_flags;
 	cfg->rc_nlinfo.portid	= NETLINK_CB(skb).portid;
 	cfg->rc_nlinfo.nlh	= nlh;
@@ -1231,7 +1245,8 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
 		    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),
+		if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC &&
+		    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);
@@ -1257,7 +1272,8 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
 							    nh->nh_labels,
 							    nh->nh_label))
 				goto nla_put_failure;
-			if (nla_put_via(skb, nh->nh_via_table,
+			if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC &&
+			    nla_put_via(skb, nh->nh_via_table,
 					mpls_nh_via(rt, nh),
 					nh->nh_via_alen))
 				goto nla_put_failure;
@@ -1319,7 +1335,8 @@ static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
 
 		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_via_table != MPLS_NEIGH_TABLE_UNSPEC) /* RTA_VIA */
+			payload += nla_total_size(2 + nh->nh_via_alen);
 		if (nh->nh_labels) /* RTA_NEWDST */
 			payload += nla_total_size(nh->nh_labels * 4);
 	} else {
@@ -1328,7 +1345,9 @@ static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
 
 		for_nexthops(rt) {
 			nhsize += nla_total_size(sizeof(struct rtnexthop));
-			nhsize += nla_total_size(2 + nh->nh_via_alen);
+			/* RTA_VIA */
+			if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC)
+				nhsize += nla_total_size(2 + nh->nh_via_alen);
 			if (nh->nh_labels)
 				nhsize += nla_total_size(nh->nh_labels * 4);
 		} endfor_nexthops(rt);