[FS#463] up/down on a usbnet interfaces fails to reassign ULA addresses

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Dave Täht (dtaht) 

Attached to Project - LEDE Project
Summary - up/down on a usbnet interfaces fails to reassign ULA addresses
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - Supply the following if possible:
 - Device problem occurs on: anything running usbnet
 - Software versions of LEDE release, packages, etc: head
 - Steps to reproduce:

Install the usbnet package, enable a usb0 device in /etc/config/network

(in my case this is a c.h.i.p, but most hackerboards except the pi do usbnet)

config interface 'usb0'                 
        option ifname 'usb0'            
        option proto 'static'                 
        option ipaddr '172.26.97.200'
        option netmask '255.255.255.255'
        option ip6assign '64'           
        option ip6class 'local' 

So long as the chip beats the router to booting, this gives it an ipv4 and ipv6 ULA out of the pool.

Reboot the device on the other side. The kernel deregisters and registers the usbnet driver, and netifd assigns the ipv4 address again. 

However the ip6 subnet that was assigned from the ula does not come back. Haven't tried it with a public address.

ifup/ifdown does not work and the ifstatus usb0 does not show any ipv6 addresses assigned. 

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=463