ospf6d, bgpd: avoid calling if_nametoindex

As the comments in if.h, it is better to call ifname2ifindex()
instead of if_nametoindex().

And ifname2ifindex() can work for VRF by appending a parameter
while if_nametoindex() can not.

Signed-off-by: Feng Lu <lu.feng@6wind.com>
Reviewed-by: Alain Ritoux <alain.ritoux@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Vincent JARDIN <vincent.jardin@6wind.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/ospf6d/ospf6_zebra.c b/ospf6d/ospf6_zebra.c
index 85f7064..ac3235c 100644
--- a/ospf6d/ospf6_zebra.c
+++ b/ospf6d/ospf6_zebra.c
@@ -443,11 +443,10 @@
     {
       if (IS_OSPF6_DEBUG_ZEBRA (SEND))
 	{
-	  char ifname[IFNAMSIZ];
+	  const char *ifname;
 	  inet_ntop (AF_INET6, &request->nexthop[i].address,
 		     buf, sizeof (buf));
-	  if (!if_indextoname(request->nexthop[i].ifindex, ifname))
-	    strlcpy(ifname, "unknown", sizeof(ifname));
+	  ifname = ifindex2ifname (request->nexthop[i].ifindex);
 	  zlog_debug ("  nexthop: %s%%%.*s(%d)", buf, IFNAMSIZ, ifname,
 		      request->nexthop[i].ifindex);
 	}