Re: [Madwifi-devel] IBSS BSSID fix for large networks - 400 nodes
Status: Beta
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From: Velt, R. (R. in 't <Ron...@tn...> - 2007-07-27 17:10:05
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Hi,=20 >=20-----Original=20Message----- >=20From:=20m...@li... [mailto:mad...@li...]=20=20On=20=20=20=20=20= =20=20Behalf=20Of Luis=20R.=20Rodriguez >=20Sent:=20woensdag=204=20juli=202007=206:18 >=20To:=20Michael=20Renzmann >=20Cc:=20madwifi-devel >=20Subject:=20Re:=20[Madwifi-devel]=20IBSS=20BSSID=20fix=20for=20large=20= networks=20-=20400 nodes > >=20On=207/4/07,=20Michael=20Renzmann=20<mre...@ma...>=20wrote: >=20>=20Hi. >=20> >=20>=20>=20nodes=20with=20identical=20SSIDs=20end=20up=20with=20identical= =20BSSIDs.=20Credit goes=20 >=20>=20>=20to=20Chris=20Davies=20from=20orderonenetworks.com=20for=20this= =20temporary=20hack. >=20> >=20>=20If=20that=20patch=20is=20not=20written=20by=20you=20it=20would=20n= eed=20to=20get=20signed=20off=20 >=20>=20[1]=20by=20the=20patch=20author=20before=20it=20can=20be=20committ= ed. > >=20That=20patch=20is=20written=20by=20me,=20its=20based=20on=20previous=20= work=20by=20Chris Davies.=20Anyway,=20its=20not=20intended=20to=20be=20merged,=20>=20but=20j= ust=20for=20review=20and comments.=20If=20people=20want=20it=20as=20an=20option=20then=20I=20can=20= merge=20it. ref: http://www.orbit-lab.org/attachment/wiki/HowTo/bssidFix/patch-01-ibss-fi x.diff IMHO=20this=20patch=20has=20a=20serious=20flaw:=20while=20this=20"hash=20a= lgorithm"=20ensures that=20nodes=20with=20identical=20SSIDs=20end=20up=20with=20identical=20BS= SIDs,=20it=20may also=20map=20*different*=20ESSIDs=20to=20the=20same=20BSSID!=20 Two=20cases: -=20ESSIDs=20that=20are=20identical=20in=20the=20first=20IEEE80211_ADDR_LE= N=20(=3D=3D=206) characters,=20but=20differ=20after=20that, -=20ESSID=20shorter=20than=20IEEE80211_ADDR_LEN=20results=20in=20repetitio= n=20of=20leading characters=20to=20achieve=20required=20BSSID=20length,=20thus=20colliding=20= with=20ESSIDs that=20have=20this=20particular=20character=20sequence,=20e.g.=20"wlan"=20= and=20"wlanwl" yield=20the=20same=20BSSID. I=20would=20suggest=20to=20use=20a=20proper=20hash=20function.=20(I=20have= =20used=20MD5,=20taking the=20leading=2048=20bits=20of=20the=20128=20hash=20as=20the=20BSSID.=20I=20= need=20to=20revise=20my code,=20since=20I=20made=20use=20of=20the=20kernel's=20crypto=20API,=20whi= ch=20was=20modified=20in 2.6.21(?)). Regards, Ronald=20in=20't=20Velt ------------------------------------------------------------------------ - This=20SF.net=20email=20is=20sponsored=20by=20DB2=20Express=20Download=20D= B2=20Express=20C=20- the=20FREE=20version=20of=20DB2=20express=20and=20take=20control=20of=20yo= ur=20XML.=20No=20limits. Just=20data.=20Click=20to=20get=20it=20now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Madwifi-devel=20mailing=20list Mad...@li... https://lists.sourceforge.net/lists/listinfo/madwifi-devel This=20e-mail=20and=20its=20contents=20are=20subject=20to=20the=20DISCLAIM= ER=20at=20http://www.tno.nl/disclaimer/email.html |