mpls: make RTA_OIF optional

If user did not specify an oif, try and get it from the via address.
If failed to get device, return with -ENODEV.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 6e669114f829d696dd77a79f0e81877b8593fc13..49f1b0e41bdf6d495fc0a015b02eeca4224a0404 100644 (file)
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -15,6 +15,7 @@
 #include <net/ip_fib.h>
 #include <net/netevent.h>
 #include <net/netns/generic.h>
+#include <net/ip6_route.h>
 #include "internal.h"
 
 #define LABEL_NOT_SPECIFIED (1<<20)
@@ -330,6 +331,70 @@ static unsigned find_free_label(struct net *net)
        return LABEL_NOT_SPECIFIED;
 }
 
+static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
+{
+       struct net_device *dev = NULL;
+       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))
+               goto errout;
+
+       dev = rt->dst.dev;
+       dev_hold(dev);
+
+       ip_rt_put(rt);
+
+errout:
+       return dev;
+}
+
+static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
+{
+       struct net_device *dev = NULL;
+       struct dst_entry *dst;
+       struct flowi6 fl6;
+
+       memset(&fl6, 0, sizeof(fl6));
+       memcpy(&fl6.daddr, addr, sizeof(struct in6_addr));
+       dst = ip6_route_output(net, NULL, &fl6);
+       if (dst->error)
+               goto errout;
+
+       dev = dst->dev;
+       dev_hold(dev);
+
+errout:
+       dst_release(dst);
+
+       return dev;
+}
+
+static struct net_device *find_outdev(struct net *net,
+                                     struct mpls_route_config *cfg)
+{
+       struct net_device *dev = NULL;
+
+       if (!cfg->rc_ifindex) {
+               switch (cfg->rc_via_table) {
+               case NEIGH_ARP_TABLE:
+                       dev = inet_fib_lookup_dev(net, cfg->rc_via);
+                       break;
+               case NEIGH_ND_TABLE:
+                       dev = inet6_fib_lookup_dev(net, cfg->rc_via);
+                       break;
+               case NEIGH_LINK_TABLE:
+                       break;
+               }
+       } else {
+               dev = dev_get_by_index(net, cfg->rc_ifindex);
+       }
+
+       return dev;
+}
+
 static int mpls_route_add(struct mpls_route_config *cfg)
 {
        struct mpls_route __rcu **platform_label;
@@ -361,7 +426,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
                goto errout;
 
        err = -ENODEV;
-       dev = dev_get_by_index(net, cfg->rc_ifindex);
+       dev = find_outdev(net, cfg);
        if (!dev)
                goto errout;