[FS#94] netifd: PPPoE MTU problem

[LEDE Bugs]

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

User who did this - Martin Schiller (ms) 

Attached to Project - LEDE Project
Summary - netifd: PPPoE MTU problem
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Medium
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - When you set the MTU of a ppp interface with proto=pppoe and ifname=nas0 via the mtu option,
the configured mtu will not be set on the ppp interface (what you want), but on the
underlying interface named by ifname (what you normally don't want to change).

This leeds to log messages like this:

----------------
pppd[5641]: Interface nas0 has MTU of 1448 -- should be at least 1500.
----------------

and MTUs other than what you really want.

example:
---------
desired PPPoE MTU: 1448
actual nas0 MTU: 1448
actual PPPoE MTU: 1440

This issue seems to be related to the commit 7ac29b75319fd69a8a7c0aeea7804d381ec07d3d of netifd.

Regards,
Martin

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=94