Date: Sun, 12 Jan 2003 18:26:24 +0100 From: Jacques Caron <Jacques.Caron@IPsector.com> To: "Ben Pfountz" <netprince@vt.edu> Cc: <chip@chocobo.cx>, <freebsd-mobile@FreeBSD.ORG> Subject: Re: wi in hostap mode causes panic near linksys router Message-ID: <5.2.0.9.0.20030112181850.02485d50@pop.mail.yahoo.com> In-Reply-To: <002101c2ba5b$53194330$6511a8c0@benspiece> References: <001401c2b9b6$5a94c1c0$6511a8c0@benspiece> <20030111.204643.06072765.imp@bsdimp.com> <20030112164138.GA31670@chocobo.cx>
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Hi, It's a bit more subtle than just "it doesn't work", really. The problem is due to the fact that 802.11 frames actually have up to 4 MAC addresses in their header, which are: - (1) the source MAC address of the frame - (2) the MAC address of the STA that sent the frame over the air - (3) the MAC address of the STA that should receive the frame over the air - (4) the destination MAC address of the frame In many cases (e.g. the AP is also a router, with "regular" clients connecting to it), (1) == (2) and (3) == (4). In a lot of other cases (the AP is a pure AP, not doing routing, still with "regular" clients connecting to it), you have either (1) == (2) or (3) == (4) (depends whether it's a frame to or from the AP). All these cases work perfectly with hostap, and the latter has the AP box acting as a bridge, so this works. What doesn't work is to have two boxes both acting as bridges, with a LAN on each side: this requires 4 different addresses, and most importantly, requires the transmitting box to know that it has to send packets with an unknown destination MAC address to the other box. This is the so-called WDS (wireless distribution system) mode, which is not currently implemented in the FreeBSD version of the hostap driver. Hope this helps, Jacques. At 17:54 12/01/2003, Ben Pfountz wrote: >Hey Chip, > >Thanks for the info. I read that too, but it must be old because the bridge >worked great when I was at home for days. > >Ben > > >On January 11, 2003, M. Warner Losh sent me the following: > > : /sbin/sysctl net.link.ether.bridge_cfg="wi0 fxp0" > > : /sbin/sysctl net.link.ether.ipfw=1 > > : /sbin/sysctl net.link.ether.bridge_ipfw=1 > > : /sbin/sysctl net.link.ether.bridge=1 > > > > I've not done bridging things with ipfw and bridge_ipfw. I've onlt > > done bridge=1. > >The bridge manpage seems to suggest that it won't work with wi, is >this just out of date, or am I misreading it? > > Bridging requires interfaces to be put in promiscuous mode, and > transmit packets with Ethernet source addresses. Some interfaces > (e.g. wi(4)) do not support this functionality. > >-- >Chip Marshall <chip@chocobo.cx> http://www.chocobo.cx/chip/ >GCM/CS d+(-) s+:++ a21>? C++ UB++++$ P+++$ L- E--- W++ N@ o K- w O M+ >V-- PS+ PE Y+ PGP++ t+@ R@ tv@ b++@ DI++++ D+(-) G++ e>++ h>++ r++ y? > > >----- Original Message ----- >From: "Chip Marshall" <chip@chocobo.cx> >To: <freebsd-mobile@FreeBSD.ORG> >Sent: Sunday, January 12, 2003 11:41 AM >Subject: Re: wi in hostap mode causes panic near linksys router > > > > >To Unsubscribe: send mail to majordomo@FreeBSD.org >with "unsubscribe freebsd-mobile" in the body of the message -- Jacques Caron, IP Sector Technologies Join the discussion on public WLAN open global roaming: http://lists.ipsector.com/listinfo/openroaming To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-mobile" in the body of the message
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