Unfortunately the concept of a native 802.11 interface got removed from the kernel a few months ago. This is a great shame, since it means that it's now impossible to write qdiscs that work correctly for WiFi when using 802.11's own priority mechanisms as well. The wlan0 interface is a virtual interface that works with 802.3 format frames.
Simon On 05/19/2010 02:01 PM, Umar Qureshey wrote: >>> -----Original Message----- >>> From: John W. Linville [mailto:[email protected]] >>> Sent: Wednesday, May 19, 2010 12:20 PM >>> To: Umar Qureshey >>> Cc: Stephen Hemminger; [email protected] >>> Subject: Re: [Bridge] Hardware requirements for bridging > wired+wireless together >>> >>> On Wed, May 19, 2010 at 10:15:35AM -0700, Umar Qureshey wrote: >>> >>>> What about bridging in Ad-Hoc mode? Would that technically work? >>> >>> No. >>> >>>> I guess what I am trying to figure out is why bridging would work > in WDS mode? What is it about that mode that allows bridging to work? >>> >>> It has to do with the MAC-layer addressing on wireless LANs. > Wireless >>> frames can use 2, 3, or 4 MAC addresses to identify the transmitter, >>> receiver, sender, and destination. For most frames and most modes, >>> 3 MAC addresses are used. The FromDS and ToDS bits in the header >>> are used to allow one of the MAC address fields to specify either >>> the transmitter and sender or the destination and receiver. This is >>> sufficient for non-bridged cases since the wireless station is either >>> an endpoint of the communication or possibly a router (and therefore >>> a Layer-2 endpoint). >>> >>> WDS (or 4 address) mode removes this limitation by using 4 MAC >>> addresses to identify all 4 roles independently. So, the wireless >>> station is able to forward frames received off the air to the >>> appropriate destination with the correct sender information intact. >>> >>> mac80211-based devices can have interfaces created with support for >>> 4 address mode using the iw command. For this to work, your AP has >>> to be willing to accept and forward those frames appropriately -- >>> some do, others don't. This is only supported for "managed" mode >>> interfaces AFAIK. >>> >>>> If one were to try to modify the kernel code to allow MAC-level > NAT, which area of the kernel code would one look at? >>> >>> netfilter -- I thought there was already some ebtables code to >>> do this...? >>> >>> John >>> -- >>> John W. Linville Someday the world will need a hero, and > you >>> [email protected] might be all we have. > Be ready. > > Ok thanks for the explanation about WDS. > > Stepping back into a Linux box with two interfaces, one Ethernet (eth0) > and one wireless 802.11 (wlan0), and one bridge (br0) that bridges these > two interfaces together: > > > br0 > | > eth0-------+-------wlan0 > > Can one say that, in this case, the bridge is not working because br0 is > passing to wlan0 Ethernet 802.3 frames which (naturally) the wlan0 > interface has no idea how to decode? > > > ********************************************************************** > This e-mail is the property of Lantronix. It is intended only for the person > or entity to which it is addressed and may contain information that is > privileged, confidential, or otherwise protected from disclosure. > Distribution or copying of this e-mail, or the information contained herein, > to anyone other than the intended recipient is prohibited. > _______________________________________________ > Bridge mailing list > [email protected] > https://lists.linux-foundation.org/mailman/listinfo/bridge _______________________________________________ Bridge mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/bridge
