[Bug 1576858] Re: brctl provides no way to set gc_timer value of a bridge

Ryan Harper 1576858 at bugs.launchpad.net
Wed May 18 15:05:28 UTC 2016

Update manpage documentation.

** Patch added: "fix-bridge-port-settings-v2.debdiff"

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  brctl provides no way to set gc_timer value of a bridge

Status in bridge-utils package in Ubuntu:

Bug description:

  % lsb_release -rd
  Description:	Ubuntu 16.04 LTS
  Release:	16.04

  2.  % apt-cache policy bridge-utils
    Installed: 1.5-9ubuntu1
    Candidate: 1.5-9ubuntu1
    Version table:
   *** 1.5-9ubuntu1 500
          500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
          100 /var/lib/dpkg/status

  3. % brctl setgcint br0 2
  Should set the gc_timer value of a bridge, value printed out via brctl showstp br0

  % brctl showstp br0 | grep gc
   topology change timer     0.00                 gc timer                  84.08

  4.  % brctl setgcint br0 2
  never heard of command [setgcint]
  Usage: brctl [commands]
  	addbr     	<bridge>		add bridge
  	delbr     	<bridge>		delete bridge
  	addif     	<bridge> <device>	add interface to bridge
  	delif     	<bridge> <device>	delete interface from bridge
  	hairpin   	<bridge> <port> {on|off}	turn hairpin on/off
  	setageing 	<bridge> <time>		set ageing time
  	setbridgeprio	<bridge> <prio>		set bridge priority
  	setfd     	<bridge> <time>		set bridge forward delay
  	sethello  	<bridge> <time>		set hello time
  	setmaxage 	<bridge> <time>		set max message age
  	setpathcost	<bridge> <port> <cost>	set path cost
  	setportprio	<bridge> <port> <prio>	set port priority
  	show      	[ <bridge> ]		show a list of bridges
  	showmacs  	<bridge>		show a list of mac addrs
  	showstp   	<bridge>		show bridge stp info
  	stp       	<bridge> {on|off}	turn stp on/off

  Checking source code of bridge-utils, there seems to be no code that lets one actually set this value, nor does it appear that the kernel ioctl interface allows for modifying gc_timer, (it appears to be a read-only field).

  This must mean the documentation included in bridge-utils
  (specifically in bridge-utils-interfaces manpage about including a
  bridge_gcint value in /etc/network/interfaces to control this is

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: bridge-utils 1.5-9ubuntu1
  ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
  Uname: Linux 4.4.0-21-generic x86_64
  NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
  ApportVersion: 2.20.1-0ubuntu2
  Architecture: amd64
  CurrentDesktop: GNOME-Flashback:GNOME
  Date: Fri Apr 29 15:53:52 2016
   gcc-6-base 6.0.1-0ubuntu1
   libc6 2.23-0ubuntu3
   libgcc1 1:6.0.1-0ubuntu1
  InstallationDate: Installed on 2016-01-01 (119 days ago)
  InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20151209)
  SourcePackage: bridge-utils
  UpgradeStatus: No upgrade log present (probably fresh install)

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