networkd: do not generate a mac address for vlan interfaces (#3221)

While creating a VLAN the mac address should be copied from the parent interface, so that
the VLANs inherit the MAC address of the physical interface.

Before:
```
3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:26:c6:85:a3:c2 brd ff:ff:ff:ff:ff:ff
    ...
6: vlan1@wlp3s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 22:07:73:9d:43:59 brd ff:ff:ff:ff:ff:ff
7: vlan2@wlp3s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 46:30:76:33:35:d4 brd ff:ff:ff:ff:ff:ff
```

After:
```
3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:26:c6:85:a3:c2 brd ff:ff:ff:ff:ff:ff
    ...
11: vlan1@wlp3s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 00:26:c6:85:a3:c2 brd ff:ff:ff:ff:ff:ff
12: vlan2@wlp3s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 00:26:c6:85:a3:c2 brd ff:ff:ff:ff:ff:ff
```

v2 of #1573, with fixed commit message.

diff --git a/src/network/networkd-netdev.c b/src/network/networkd-netdev.c
index d7d014f05da7ec2a9da6ff21cfad928bb4fe9347..851a36290cfdeb924a520f939ba0b7a04e311f2b 100644 (file)
--- a/src/network/networkd-netdev.c
+++ b/src/network/networkd-netdev.c
@@ -656,7 +656,7 @@ static int netdev_load_one(Manager *manager, const char *filename) {
         if (!netdev->filename)
                 return log_oom();
 
-        if (!netdev->mac) {
+        if (!netdev->mac && netdev->kind != NETDEV_KIND_VLAN) {
                 r = netdev_get_mac(netdev->ifname, &netdev->mac);
                 if (r < 0)
                         return log_error_errno(r, "Failed to generate predictable MAC address for %s: %m", netdev->ifname);