From mboxrd@z Thu Jan 1 00:00:00 1970 From: Inaky Perez-Gonzalez Subject: Re: What makes a good fake MAC address? Date: Wed, 22 Apr 2009 14:28:03 -0700 Message-ID: <200904221428.03539.inaky@linux.intel.com> References: <200904221348.27357.inaky@linux.intel.com> <49EF8891.9010306@cosmosbay.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from mga07.intel.com ([143.182.124.22]:46176 "EHLO azsmga101.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754291AbZDVV2H convert rfc822-to-8bit (ORCPT ); Wed, 22 Apr 2009 17:28:07 -0400 In-Reply-To: <49EF8891.9010306@cosmosbay.com> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Wednesday 22 April 2009, Eric Dumazet wrote: > Inaky Perez-Gonzalez a =E9crit : > > Hi All > > > > The Intel i2400m WiMAX driver behaves as an ethernet device, and > > currently when sending packets to the netdev stack, it fakes an eth= ernet > > header, sets the "from" mac address to zeroes and the "to" to it's = own > > MAC address. > > > > The WiMAX network can be considered to be a point-to-point (up to t= he > > gateway) connection, all IP based, so there are not MAC addresses f= rom > > our gateway (not to mention that it can change behind us). > > > > The problem with using a zero mac address is that it confuses the > > bridging software (and maybe others). I was wondering, what would b= e a > > fake mac address we could put in there that is legal for this kind = of > > "faking"? [or the closest thing to legal?] > > > > Thanks! > > We have random_ether_addr(), it should be self explained :) (Also in reply to Stephen's comment) the device has its own local addre= ss;=20 what we are faking is the address the packet comes from. According to random_ether_addr(), it sets the local bits; will this wor= k to=20 fake the "other end of the connection"? (for which there is an IP addre= ss but=20 no MAC address, it being a pure IP link). Thanks, --=20 Inaky