set MTU to 1438 by default

1 files changed, 3 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
index f4672b5..dfe63d4 100644
--- a/src/main.c
+++ b/src/main.c
@@ -31,12 +31,15 @@ static void setup_tundev(const char *in_ifname)
 	struct ifreq ifr2;
 	memset(&ifr2, 0, sizeof(ifr2));
 	ifr2.ifr_flags = IFF_UP|IFF_RUNNING;
+	ifr2.ifr_mtu = 1438;
 	strncpy(ifr2.ifr_name, in_ifname, IFNAMSIZ - 1);
 	int tmpfd = socket(AF_INET, SOCK_DGRAM, 0);
 	if (tmpfd < 0)
 		fatal("setup_tundev: socket(): %s", strerror(errno));
 	if (ioctl(tmpfd, SIOCSIFFLAGS, &ifr2) < 0)
 		fatal("setup_tundev: ioctl(SIOCSIFFLAGS): %s", strerror(errno));
+	if (ioctl(tmpfd, SIOCSIFMTU, &ifr2) < 0)
+		fatal("setup_tundev: ioctl(SIOCSIFMTU): %s", strerror(errno));
 	close(tmpfd);
 
 	tun_fd = fd;