Bug 156118 - phantom bad UDP packets detected by NetworkManager
phantom bad UDP packets detected by NetworkManager
Product: Fedora
Classification: Fedora
Component: NetworkManager (Show other bugs)
All Linux
medium Severity medium
: ---
: ---
Assigned To: Dan Williams
Depends On:
Blocks: FC4Target
  Show dependency treegraph
Reported: 2005-04-27 13:41 EDT by joe barnett
Modified: 2007-11-30 17:11 EST (History)
0 users

See Also:
Fixed In Version: 0.6.x
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2007-10-31 22:50:03 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
NM log (241.63 KB, text/plain)
2005-04-27 13:41 EDT, joe barnett
no flags Details

  None (edit)
Description joe barnett 2005-04-27 13:41:10 EDT
Description of problem:
When I try to connect to a wireless network using STABLE-0.3 branch of CVS, I
often am unable to.  NetworkManager reports "Reply message was not UDP
(ip_hdr->protocol = 6, IPPROTO_UDP = 17), won't use it." (Full NM log attached)

However, when I run ethereal concurrently, it shows no traffic on the wlan0
interface, except for the outgoing UDP DHCP packets, which never receive a response.

One thing I have noticed is that if i replug and unplug the wired ethernet cable
repeatedly, sometimes NM will be able to grab a wireless IP when I plug the
cable in...

Also, once this happens, plugging the ethernet cable back in does not result in
NM receiving an event to bring up the wired interface.

System information:
 Network controller: Broadcom Corporation BCM4306 802.11b/g Wireless LAN
Controller (rev 03) on wlan0 under ndiswrapper driver
 Ethernet controller: Broadcom Corporation NetXtreme BCM5751 Gigabit Ethernet
PCI Express (rev 01) on eth0 under tg3 driver
Comment 1 joe barnett 2005-04-27 13:41:11 EDT
Created attachment 113726 [details]
NM log
Comment 2 joe barnett 2005-04-30 15:47:22 EDT
I'm not exactly sure why, but it seems to be working now, even with no changes
to the NM code...

The only thing I can think that I changed was that I set the BIOS to do a full
POST on boot to workaround an ndiswrapper bug (loading ndiswrapper freezes the
machine if boot without power cable plugged in and the BIOS only does a minimal
post).  for reference, my laptop is a Dell Latitude D810, but I've also seen the
NM bug on a Dell Inspiron 8600.
Comment 3 Dan Williams 2005-05-05 15:12:27 EDT
wierd...  all NM is doing is reading from a socket with recv()-type calls.  Is
there possibly a "dhclient" running at the same time as NetworkManager is
running?  If you've got any of your devices marked to start on boot, that might
be the cause of a dhclient process running.
Comment 4 joe barnett 2005-05-05 16:00:30 EDT
I shouldn't have any other dhcp client running at the same time...  here's my
/etc/network/interfaces (running ubuntu, not fedora):

auto lo
iface lo inet loopback
iface eth0 inet dhcp
iface wlan0 inet dhcp
Comment 5 Dan Williams 2005-05-18 09:58:19 EDT
I think the issue here is that the code is simply pulling packets from the
networking stack.  Unfortunately, because we're doing that at the packet layer
and _not_ the ethernet layer, we have no way of masking out traffic on other
interfaces.  So, the DHCP code will actually receive traffic on eth0 when its
trying to do DHCP on eth1.

Now, this is OK because the code checks the 'xid' of the message, and discards
it if its not the same as the DHCP request we sent out.  But it does mean more
spew in the logs.  I might try to counteract this by taking out some of the
debug messages.
Comment 6 Dan Williams 2007-10-31 22:50:03 EDT
Fixed with NM 0.6.x in FC6 and later...

Note You need to log in before you can comment on or make changes to this bug.