dhclient conflict between /sbin/devd and /etc/rc.d/netif ?

[Brooks Davis]

On Mon, Feb 11, 2008 at 06:51:58PM +1100, Robert Jenssen wrote:
> Hi Brooks and all,
> 
> On Mon, 11 Feb 2008 12:06:26 pm you wrote:
> > On Mon, Feb 11, 2008 at 11:37:21AM +1100, Robert Jenssen wrote:
> > > Hi,
> > > Every so often I have trouble connecting rt2560 based PCI wireless network 
> > > card to my wireless router/access point. Typically I get:
> > > 
> > > # sudo /etc/rc.d/netif restart ral0
> > > Starting wpa_supplicant.
> > > ral0: no link .............. giving up
> > > ral0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> > >         ether 00:11:50:63:cd:47
> > >         media: IEEE 802.11 Wireless Ethernet autoselect (DS/1Mbps)
> > >         status: no carrier
> > > 
> > > Even though there seems to be plenty of signal power:
> > > 
> > > # sudo ifconfig ral0 list scan
> > > SSID            BSSID              CHAN RATE   S:N     INT CAPS
> > > xxxxxxx...      00:xx:xx:xx:xx:xx   10   54M -74:-95  100 EPS  WPA
> > > 
> > > Recently I noticed that sometimes, after the above "netif restart" fails, 
> the 
> > > ral0 interface "automagically" comes up anyway. Then dhclient is owned 
> > > by /sbin/devd. The default devd.conf starts dhclient for both ethernet and 
> > > PCI-cardbus devices. Is it a good idea for both /sbin/devd 
> > > and /etc/rc.d/netif to start a dhclient on ral0 at about the same time? 
> 
> In the "magical" case above what I think is happening is that the dhclient 
> startup from /etc/rc.d/netif called by rc fails. Later /etc/rc.d/netif is 
> called again from /etc/pccard_ether:pccard_ether_start() by /sbin/devd. That 
> call succeeds. 

As long as the interface is in the "up" state, /etc/pccard_ether will ignore
the interface.  I'm fairly sure we don't configure interfaces twice, though
it's probably worth verifying that that's the case.

> The rc system uses rcorder to determine the order in which to run the rc 
> scripts. On my system rcorder shows devd fairly early in the list. The 
> devd.conf file calls a number of rc scripts. So far as I can see /sbin/devd 
> doesn't check that these are called in the order listed by rcorder. Is this a 
> problem? 

Not generally, though it's vaguely possible there are still problems around.
The general idea is that all scripts devd should always be safe to call.

> I have disabled devd (set the moused port explicitly in rc.conf) and done some 
> simple tests on /usr/src/sbin/dhclient.c. In particular, at line 365 main() 
> allows a hard-coded maximum of 10 seconds for the call to 
> interface_link_status() to succeed. I changed this to 20 seconds with a print 
> out and ran /etc/rc.d/netif restart a few times with rc_debug="YES". The 
> results were
> 15 15 5 5 5 5 5 15 15 5 5 5 5 5 21(timed out!) 5 5 and 5 seconds. Presumably 
> the (10n+5) seconds is a magic number inside my wireless card or router. I'm 
> going to set the hardcoded value to 25 seconds. Would it be possible for you 
> to commit a similar change?

Sorry, no chance.  It's too long for most people already.

> ("diff -C 5" to show the sleep()s!). Rather than dhclient.c timing 10 seconds 
> and calling exit(), as shown above, shouldn't the dhclient.conf "timeout" 
> configuration item cover this situation? I see that PR bin/98577 wants this 
> hardcoded timeout reduced or made adjustable via dhclient.conf.

Some sort of link-timeout parameter might be acceptable as a new configuration
option.

-- Brooks

P.S. Your interface appears to be getting an address.  Don't you have anything
better to worry about? :-)
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