[FS#4042] netifd forces up dhcp interfaces set admin-down with "ip link set $I down"

[OpenWrt Bugs]

THIS IS AN AUTOMATED MESSAGE, DO NOT REPLY.

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

User who did this - Brad G (BradG) 

Attached to Project - OpenWrt/LEDE Project
Summary - netifd forces up dhcp interfaces set admin-down with "ip link set $I down"
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Medium
Priority - Very Low
Reported Version - openwrt-21.02
Due in Version - Undecided
Due Date - Undecided
Details - netifd will immediately and automatically set an interface active/up which has been administratively disabled with either the "ip link set $I down" or "ifconfig $I down" commands.

This problem will only occur if the interface proto is configured for "dhcp" rather than "static". This appears to be related to the behavior induced by the "force_link" option, however force_link suppresses hotplug events (which breaks my use-case) and probably has other undesirable side-effects.

Below is a sample log where "ip link set eth0.1 down" is used against the "lan" interface-configuration. Note that identical behavior is also observed on a typical ethernet interface (eth0) where there is no intermediate switch or VLAN-interfaces involved.

Sat Sep 11 00:39:59 2021 daemon.notice netifd: VLAN 'eth0.1' link is down
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' has link connectivity loss
Sat Sep 11 00:39:59 2021 kern.info kernel: [48844.417075] device eth0 left promiscuous mode
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (28106): udhcpc: received SIGTERM
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is now down
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is disabled
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is enabled
Sat Sep 11 00:39:59 2021 daemon.notice netifd: VLAN 'eth0.1' link is up
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' has link connectivity
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is setting up now
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: started, v1.30.1
Sat Sep 11 00:39:59 2021 kern.info kernel: [48845.042493] device eth0 entered promiscuous mode
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: sending discover
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: sending select for 192.168.0.148
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: lease of 192.168.0.148 obtained, lease time 43200
Sat Sep 11 00:40:00 2021 daemon.notice netifd: Interface 'lan' is now up
Sat Sep 11 00:40:01 2021 user.notice firewall: Reloading firewall due to ifup of lan (eth0.1)

This behavior was verified on multiple 21.02 and 19.07 devices.

More information can be found at the following URL:
https://bugs.openwrt.org/index.php?do=details&task_id=4042

You are receiving this message because you have requested it from the Flyspray bugtracking system.  If you did not expect this message or don't want to receive mails in future, you can change your notification settings at the URL shown above.