fix tftpd service so it is functional on HA
A TrueNAS customer is trying to use tftp services on HA. inetd listens on 0.0.0.0 without problems (verified with sockstat), but tftpd seems to not be okay with that. When tftpd is run, communication problems occur and tftp services will not work.
By binding inetd services to the virtual IP specifically, then everything works. This was accomplished by adding the IP address to inetd by editing the line in /etc/rc.conf and adding the inetd flag "-a IP.ad.dr.ess".
NOTE: The issues documented in this ticket meansthat tftp is non-functional for all HA systems until this is fixed!
The recommended action is to add a binding IP address option to the GUI, similar to all other services, and allow the end-user to bind to the IP address specifically through the WebGUI. Alternatively, an extra options field could be added to the WebGUI to allow for passing of parameters to inetd. Per the manpage, tftpd doesn't have any specific flags to listen to a specific IP because it works through inetd.
I do have tcpdumps of this working and non-working for the customer, and can be provided on request. I will keep them until the end of the year as they are fairly large and cannot be attached to the bug.