Marcin Szewczyk <marcin.szewc...@wodny.org> writes: > On Wed, Jun 13, 2012 at 07:58:18PM +0200, Bjørn Mork wrote: >> Marcin Szewczyk <marcin.szewc...@wodny.org> writes: >> > When using RNDIS wwan0 interface has MAC address 02:50:f3:00:00:00 while >> > packets coming from Internet have destination MAC address set to >> > 00:01:02:03:04:05. So the workaround is to set wwan0 MAC to that value. >> >> I guess the 02:50:f3:00:00:00 comes from a USB descriptor as it's not >> exactly random. > > You're right. As You suggested - it is visible as iMacAddress in lsusb > output. > >> So if the firmware provides this descriptor while using >> another fixed address, then that is certainly a firmware bug. Not too >> surprising unfortunately... > > Roger. > >> Normally such devices will pick the MAC address they see in the DHCP >> discover message, but that doesn't seem to happen here unless you sent a >> DHCP request with 00:01:02:03:04:05 as MAC source address? > > Negative. MAC address set for the interface was used. > > Another thing worth noticing is that 02:50:f3:00:00:00 is used as the > destination address for outgoing packets and source address for > returning packets. Both before and after setting interface MAC address.
Yuck! Looks like someone put the wrong address into the string descriptor. >> What does lsusb -v say? > > Output attached. Yes, as expected. Fixing the mac address string descriptor shouldn't be a big problem for Huawei. I don't think there is any existing infrastructure in place for overriding it in Linux. And I believe it shouldn't be added either, given that: - your modem is the only affected one AFAIK, - a usable workaround exists, - the firmware bug is extremely easy to fix for Huawei (and might already be fixed for all we know) >> Or you can bug Huawei about it... > > I will check if Huawei cares... > >> Another option would be using another usb_modeswitch command. These >> modems often support many different USB descriptor sets, selectable by >> the usb_modeswitch command. For some reason, Huawei thinks that it is a >> good idea to use different USB descriptors for Linux and Windows. Guess >> which set is tested... You could sniff the device under Windows, find >> out what the Windows driver does, and try that in Linux as well. > > I will search for a Windows PC... > > Thank You for a reply. I've also uploaded two tcpdumps: > 1) one with default MAC > http://wodny.org/special/huawei/huawei-e137-wwan0-defaultmac.cap > 2) one with MAC manually set to 00:01:02:03:04:05 > http://wodny.org/special/huawei/huawei-e137-wwan0-00-05-mac.cap Thanks. That demonstrates the problem really well. Bjørn -- To UNSUBSCRIBE, email to debian-kernel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/87bokenzaq....@nemi.mork.no