vyos.ifconfig: get_mac_synthetic() must generate a stable "MAC"

Commit b7d30137b1 ("vyos.ifconfig: provide generic get_mac_synthetic() method")
provided a common helper to generate MAC addresses used by EUI64 addresses for
interfaces not having a layer2 interface (WireGuard or ip tunnel).

The problem is that every call to the helper always yielded a new MAC address.
This becomes problematic when IPv6 link-local addresses are generated and
modified on the interface as multiple link-local (fe80::/64) addresses can
easily be added to the interface leaving ... a mess.

This commit changes the way how the "synthetic" MAC is generated, we generate a
UUID which is stable as it is based on the interface name. We take out the last
48 bits of the UUID and form the "MAC" address.

0 files changed, 0 insertions, 0 deletions