ppp link-layer address configuration is wrong #94107
Description
Describe the bug
This is a 4.2 backport issue for main fix in #93955
Restore setting the ppp link-local address either to CONFIG_PPP_MAC_ADDR or to a random value 00:00:5e:00:53:XX instead of leaving it uninitialized.
Recently the memory handling for the link-layer addresses was changed from an approach of copying pointers to managing the memory as a member of the net_linkaddr struct (ref ac3cb9d).
The piece of code this patch touches however, relied on the use of the pointers to function properly.
With the recent change, the MAC address was copied to the new member location before it was even set (either from Kconfig or selected randomly). As a result, the link-layer address was kept initialized to zero, which resulted in a IPv6 address of fe80::ff:fe00:0 which is exactly the link-local EUI-64 representation of the MAC address 00:00:00:00:00:00 (without flipping the "universal/local" bit).
The bug was introduced with the recent Zephyr 4.2.
Regression
- This is a regression.
Steps to reproduce
No response
Relevant log output
Impact
Annoyance – Minor irritation; no significant impact on usability or functionality.
Environment
No response
Additional Context
No response