Do not overwrite user-specified MTU.

Allow to use different size than the default of 32K.

ok henning@, stsp@, florian@, benno@ as part of a larger diff.

diff --git a/sys/net/if_loop.c b/sys/net/if_loop.c
index b1477be..de83df5 100644 (file)
--- a/sys/net/if_loop.c
+++ b/sys/net/if_loop.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_loop.c,v 1.62 2014/12/19 17:14:39 tedu Exp $       */
+/*     $OpenBSD: if_loop.c,v 1.63 2015/01/27 10:20:31 mpi Exp $        */
 /*     $NetBSD: if_loop.c,v 1.15 1996/05/07 02:40:33 thorpej Exp $     */
 
 /*
@@ -271,7 +271,7 @@ looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 void
 lortrequest(int cmd, struct rtentry *rt)
 {
-       if (rt)
+       if (rt && rt->rt_rmx.rmx_mtu == 0)
                rt->rt_rmx.rmx_mtu = LOMTU;
 }