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rainbowgoblin

Member

Registered: 2013-08-14

Posts: 12

Software access point: can't set AP up

I'm attempting to follow the software access point guide and running into a snag pretty early on. I've run the following commands successfully:

[root@mycomputer expressvpn] iw dev wlp3s0 interface add wlp3s0_sta type station
[root@mycomputer expressvpn] iw dev wlp3s0 interface add wlp3s0_ap type  __ap
[root@mycomputer expressvpn] ip link set dev wlp3s0_sta address 12:34:56:78:ab:cd
RTNETLINK answers: Device or resource busy
[root@mycomputer expressvpn]# ip link set dev wlp3s0_sta down
[root@mycomputer expressvpn]# ip link set dev wlp3s0_sta address 12:34:56:78:ab:cd
[root@mycomputer expressvpn]# ip link set dev wlp3s0_ap address 12:34:56:78:ab:ce

As you can see, I initially had to set the station virtual interface "down" before giving it a fake MAC address, but otherwise the whole thing seemed to work. Next I try to bring up the station and host virtual interfaces:

[root@mycomputer expressvpn]# ip link set dev wlp3s0_sta up
[root@mycomputer expressvpn]# ip link set dev wlp3s0_ap up 
RTNETLINK answers: Operation not supported

And here I'm stuck. I'm sure there's an answer out there on Google, but I haven't been able to find it... is this an indication that I'm missing a kernel module? I've modprobe'd tun and checked lsmod to make sure it got loaded. My wifi card seems to support AP mode:

Wiphy phy0
        max # scan SSIDs: 20
        max scan IEs length: 195 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Device supports RSN-IBSS.
        Supported Ciphers:
                * WEP40 (00-0f-ac:1)
                * WEP104 (00-0f-ac:5)
                * TKIP (00-0f-ac:2)
                * CCMP (00-0f-ac:4)
        Available Antennas: TX 0 RX 0
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * monitor
...

branch

Member

Registered: 2014-03-16

Posts: 209

Re: Software access point: can't set AP up

The link you referenced tells you that for this configuration your device must explicitely support simultaneous AP and client modes; just supporting AP mode is not enough. It tells you how to determine if your device supports this.

On a side note, are you sure you actually need simultaneous client and AP? Or are you just trying to make a regular access point?

rainbowgoblin

Member

Registered: 2013-08-14

Posts: 12

Re: Software access point: can't set AP up

Right. I guess I didn't really understand that part of the guide... the "valid interface combinations" output it quotes from iw list includes a lot of numbers, and they only one they refer to specifically is the channel. Anyway, that section from my system gives the following:

        valid interface combinations:
                 * #{ managed } <= 1, #{ AP } <= 1,
                   total <= 2, #channels <= 1, STA/AP BI must match
                 * #{ managed } <= 2,
                   total <= 2, #channels <= 1

Does this mean I can only have one AP, or one one client, plus the AP?

I THINK I need simultaneous client and AP. I'd like to use my wireless interface to connect to the internet and to provide the AP.