lxc_user_nic: fix get_mtu() error handling

[mirror_lxc.git] / src / lxc / cmd / lxc_user_nic.c

diff --git a/src/lxc/cmd/lxc_user_nic.c b/src/lxc/cmd/lxc_user_nic.c
index a91e2259d56c4f4eac342314988254c3f6230f55..0068967509c147966c61afa669d759e782cca265 100644 (file)
--- a/src/lxc/cmd/lxc_user_nic.c
+++ b/src/lxc/cmd/lxc_user_nic.c
@@ -489,20 +489,30 @@ static int instantiate_veth(char *veth1, char *veth2, pid_t pid, unsigned int mt
        return netdev_set_flag(veth1, IFF_UP);
 }
 
-static int get_mtu(char *name)
+#define NETDEV_MTU_DEFAULT 1500
+
+static unsigned int get_mtu(char *name)
 {
-       int idx;
+       int idx, val;
 
        idx = if_nametoindex(name);
-       if (idx < 0)
-               return -1;
+       if (idx < 0) {
+               usernic_error("Could not find netdev %s\n", name);
+               return NETDEV_MTU_DEFAULT;
+       }
+
+       val = netdev_get_mtu(idx);
+       if (val < 0) {
+               usernic_error("Could not get MTU for netdev %s ifindex %d\n", name, idx);
+               return NETDEV_MTU_DEFAULT;
+       }
 
-       return netdev_get_mtu(idx);
+       return val;
 }
 
 static int create_nic(char *nic, char *br, int pid, char **cnic)
 {
-       unsigned int mtu = 1500;
+       unsigned int mtu = NETDEV_MTU_DEFAULT;
        int ret;
        char veth1buf[IFNAMSIZ], veth2buf[IFNAMSIZ];
 
@@ -520,8 +530,6 @@ static int create_nic(char *nic, char *br, int pid, char **cnic)
 
        if (strcmp(br, "none"))
                mtu = get_mtu(br);
-       if (!mtu)
-               mtu = 1500;
 
        /* create the nics */
        ret = instantiate_veth(veth1buf, veth2buf, pid, mtu);