Prism / Hostap Bridge Problems...

[Joe Parks]

On Fri, 10 Dec 2004 15:47:05 +0100
Brande <brande at novolab.de> wrote:


> Problem:
> 
> I have a meshcube (www.meshcube.org) with two prim 2.5 mini-pci WLAN 
> cards...
> wlan0 should connect as client (managed mode) to a normal access point 
> which is connected to the internet.
> wlan1 should work as accesspoint (master mode).
> I would like to bridge between wlan0 and wlan1 so that I can connect 
> with my Laptop Client2 to the AccessPoint on wlan1 and go, through the 
> wlan0 client connection to the normal AccessPoint, to the internet...

What you are trying to do can't be done with bridging.   Only WDS connections carry the addr fields needed to accomplish that, and since your primary access point (presumably) isn't something you can configure to use WDS you'll have to solve your problem at layer 3 (TCP/IP routing).

It is, however, not difficult to get your desired result just by setting the IP addr of your "Master" mode wifi card to a different subnet (such as 192.168.1.x) and setting laptops you want to talk through it to addrs on that same subnet, with the "Master" card's IP as their gateway.

The line:
>                 echo "1" > /proc/sys/net/ipv4/ip_forward               IS necessary to get *routing* working.  You'll have to use it for the workable solution I describe above.

Of course the solution I describes assumes you won't be trying to *roam* between the primary access point and the one you are setting up, but only using your hostap box to connect that laptop.

 
> 
> So here is the hardware setup:
> 
> Internet ----- AccessPoint (192.168.0.1) -------- CLient/AP Bridge 
> (192.168.0.100 (2 cards in one box))
>                                   |                                    
>                |
>                       Laptop Client 1                            my 
> Laptop CLient 2
>                       (192.168.0.33)                               
> (192.168.0.117)
> 
> 
> The data of the WLAN devices:
> 
> hostap_diag wlan0
> Host AP driver diagnostics information for 'wlan0'
> 
> NICID: id=0x8013 v1.0.0 (PRISM II (2.5) Mini-PCI (SST parallel flash))
> PRIID: id=0x0015 v1.1.1
> STAID: id=0x001f v1.7.4 (station firmware)agnostics information for 'wlan0'
> 
> hostap_diag wlan1
> Host AP driver diagnostics information for 'wlan1'
> 
> NICID: id=0x8013 v1.0.0 (PRISM II (2.5) Mini-PCI (SST parallel flash))
> PRIID: id=0x0015 v1.1.1
> STAID: id=0x001f v1.7.4 (station firmware)agnostics information for 'wlan0'
> 
> 
> I have written the following bridge script:
> 
> ETHER0=wlan0
> ETHER1=wlan1
> BRIDGE=br0
> BRIDGEIP=192.168.0.100
> BRIDGEGW=192.168.0.1
> BRIDGENM=255.255.255.0
> BRIDGESTP=off           ### must be "on" with more then one bridge
> 
> ### stop configure ###
> 
> 
> echo -n "stopping firewall: "
> 
>    iptables -F
>    iptables -F -t nat
>    iptables -P INPUT ACCEPT
>    iptables -P FORWARD ACCEPT
>    iptables -P OUTPUT ACCEPT
> 
>    echo "*** network is insecure now *** "
> 
> echo "done."
> 
> 
> case "$1" in
> 
>     start)
>         echo "Starting service bridge br0"
>         echo "Bridge IP will be: $BRIDGEIP"
>                 ifconfig $ETHER0 promisc up
>                 ifconfig $ETHER1 promisc up
>                 sleep 2
>         brctl addbr $BRIDGE
>         brctl setbridgeprio $BRIDGE 0
>                 ifconfig $ETHER0 0.0.0.0
>                 ifconfig $ETHER1 0.0.0.0
>         brctl addif $BRIDGE $ETHER0
>         brctl addif $BRIDGE $ETHER1
>         #brctl stp $BRIDGE $BRIDGESTP
>         #brctl sethello $BRIDGE 1
>         #brctl setmaxage $BRIDGE 4
>         #brctl setfd $BRIDGE 4
>                 echo "1" > /proc/sys/net/ipv4/ip_forward               
>             # I know it's not really neccessary
>                 ifconfig $BRIDGE $BRIDGEIP netmask $BRIDGENM up   # but 
> it was a test
>                 route add default gw $BRIDGEGW $BRIDGE
>         echo -e "Bridge needs 30 sec. to learn table!\n(depends on 
> kernel version...)\n"
>         ;;
> 
> 
> If I start the script the bridge goes up and I can ping the bridge 
> (192.168.0.100) from outside with the Laptop Client 1. I can also ping 
> my Laptop Client2 from outside but from my Laptop Client2 I can not ping 
> the gateway behind the bridge (192.168.0.1) or the Laptop Client1 but I 
> can ping the bridge interface from my Laptop Client2 which is connected 
> to the WLAN1 AccessPoint in the bridge...
> 
> With tcpdump I can see that the there is an arp request from my Laptop 
> Client2 on the bridge interface to see who has 192.168.0.1 if I try to 
> ping e.g. 192.168.0.1 but I get no reply from the bridge. On my Laptop I 
> get the message "Host unreachable".
> Looks like that the AccessPoint or the Client in the bridge, the MAC 
> address within the arp request from my Laptop Client1 to the one of the 
> correspondig interfaces inside the bridge replaced and that that is the 
> reason while I can't receive the answer to my arp request. Might this be 
> possible? And if - do you know a solution to solve that problem? Or do 
> you have another solution with the same effect but without wds please;)
> 
> 
> 
> Thanks for your time,
>     have fun,
>        Brande
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