set MTU on tunnel interface so the kernel will re-fragment large packets to within MRU

[l2tpns.git] / l2tpns.c

diff --git a/l2tpns.c b/l2tpns.c
index c66400d..816d27f 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.149 2005-11-17 06:46:24 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.150 2005-11-17 07:35:35 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -554,6 +554,13 @@ static void inittun(void)
                LOG(0, 0, 0, "Error setting tun queue length: %s\n", strerror(errno));
                exit(1);
        }
+       /* set MTU to modem MRU + 4 (tun header) */
+       ifr.ifr_mtu = MRU + 4;
+       if (ioctl(ifrfd, SIOCSIFMTU, (void *) &ifr) < 0)
+       {
+               LOG(0, 0, 0, "Error setting tun MTU: %s\n", strerror(errno));
+               exit(1);
+       }
        ifr.ifr_flags = IFF_UP;
        if (ioctl(ifrfd, SIOCSIFFLAGS, (void *) &ifr) < 0)
        {