Not sure if it's kern/ or bin/, both are involved I guess. Renaming vmnet/tap(4) interfaces, defined in rc.conf(5) via "cloned_interfaces" e.g, isn't prohibited by rc(8)-network.subr nor by ifconfig(8). If such a interface is renamed, the Ethernet device shows up correctly, with the new name and ifconfig(8) also reports the new name if it's created and renamed in the same invocation. Problem is, the control device isn't renamed, it will keep it's initial creation name like tap0 and I found no userland way to determine the corresponding Ethernet IF name. -harry
Take... I could see some use in creating an alias for it, but I'd like to see how this usually works in other OS.
Author: kevans Date: Thu Oct 3 17:54:00 2019 New Revision: 353057 URL: https://svnweb.freebsd.org/changeset/base/353057 Log: if_tuntap: create /dev aliases when a tuntap device gets renamed Currently, if you do: $ ifconfig tun0 create $ ifconfig tun0 name wg0 $ ls -l /dev | egrep 'wg|tun' You will see tun0, but no wg0. In fact, it's slightly more annoying to make the association between the new name and the old name in order to open the device (if it hadn't been opened during the rename). Register an eventhandler for ifnet_arrival_events and catch interface renames. We can determine if the ifnet is a tun easily enough from the if_dname, which matches the cevsw.d_name from the associated tuntap_driver. Some locking dance is required because renames don't require the device to be opened, so it could go away in the middle of handling the ioctl, but as soon as we've verified this isn't the case we can attempt to busy the tun and either bail out if the tun device is dying, or we can proceed with the rename. We only create these aliases on a best-effort basis. Renaming a tun device to "usbctl", which doesn't exist as an ifnet but does as a /dev, is clearly not that disastrous, but we can't and won't create a /dev for that.
If this can/should goto releng/12.1, please set bug 240700 in this issues Blocks field
I MFC'd this to stable/12 a while ago with a bunch of other stuff; will not be going to stable/11.