kern/39236: Network interface order problem: /etc/ifconfig.bridge* is started too early

[randolf+netbsd.org%inter-corporate.com@localhost]

>Number:         39236
>Category:       kern
>Synopsis:       Network interface order problem:  /etc/ifconfig.bridge* is 
>started too early
>Confidential:   no
>Severity:       critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Mon Jul 28 06:30:01 +0000 2008
>Originator:     Randolf Richardson
>Release:        NetBSD v4.99.70
>Organization:
Inter-Corporate Computer & Network Services, Inc.
>Environment:
NetBSD netbsd.test.lumbercartel.ca 4.99.70 NetBSD 4.99.70 (XEN3_DOM0) #0: Mon 
Jul 21 04:34:08 PDT 2008  
builds@wb38:/home/builds/ab/HEAD/i386/200807210002Z-obj/home/builds/ab/HEAD/src/sys/arch/i386/compile/XEN3_DOM0
 i386
>Description:
When I set up ifconfig.tap0 and also ifconfig.bridge0 to bridge to it, the tap0 
interface hasn't started yet and so the bridge configuration fails.

My recommendation is to do one of the following:

   * change the order that interfaces are initialized in so that 
ifconfig.bridge* comes [at least] after ifconfig.tap* (not before)

   * document the order (if it's consistent) in "man ifconfig.if"

   * add support for "before interface-name[, interface-name[, ...]]" and 
"after interface-name[, interface-name[, ...]]" directives in ifconfig.* files 
to allow dependencies to be configured easily

I would prefer to see the third solution implemented because it provides the 
most flexibility.

Thanks in advance.

>How-To-Repeat:
Here are the relevant ifconfig.* files, after implementing the work-around 
(describe in the "fix" section below):

netbsd# cat /etc/ifconfig.tap0
create
inet 10.88.1.1/24
!brconfig bridge0 add $int up

netbsd# cat /etc/ifconfig.bridge0
create

-----

Here are the same files that result in the failure to create the bridge:

netbsd# cat /etc/ifconfig.tap0
create
inet 10.88.1.1/24

netbsd# cat /etc/ifconfig.bridge0
create
!brconfig $int add tap0 up

>Fix:
To work-around, I have to configure the bridge in my ifconfig.tap0 file 
instead, which is okay but leaves me wondering if the order is clearly defined 
or based on other factors (e.g., the order in which the ifconfig.* files were 
created).

The "other factors" is the reason for setting the severity to "critical" since 
a reboot could leave a system without bridging, and possibly non-functional 
(e.g., OpenVPN is used for secure access, and without the bridge it may not be 
remotely accessible).