[ath9k-devel] Connecting multiple times to same base station

[ath9k-devel] Connecting multiple times to same base station

[Kilian Risse]

Hi all

I tried to simulate multiple clients through a single ar93xx card. I
noticed that even though I connect with the base station multiple times
through several interfaces, the MAC address with which I send packets
(and am associated to the access point) remains the same; the one of the
primary station.

The interfaces have all different MAC addresses and they have different
IPs. But whenever I arping any of the IP addresses it returns the MAC of
the primary station.

I wanted to ask whether this is intended behavior (and the use case not
supported) or whether this is a bug.

Thanks for the help

Kilian

[ath9k-devel] Connecting multiple times to same base station

[Michal Kazior]

On 15 June 2015 at 09:47, Kilian Risse <krisse@student.ethz.ch> wrote:
> Hi all
>
> I tried to simulate multiple clients through a single ar93xx card. I
> noticed that even though I connect with the base station multiple times
> through several interfaces, the MAC address with which I send packets
> (and am associated to the access point) remains the same; the one of the
> primary station.
>
> The interfaces have all different MAC addresses and they have different
> IPs. But whenever I arping any of the IP addresses it returns the MAC of
> the primary station.

I'm guessing you're using the same IP subnet on all of them.

You'll need to either tune IP routing
(https://lwn.net/Articles/364318/) and/or force sockets to bind to
interfaces (e.g. ping with "-I" parameter).

Personally, I often use ipv6 link-local addresses to test traffic on
such topologies to avoid the problem.


Micha?

[ath9k-devel] Connecting multiple times to same base station

[Kilian Risse]

Thanks for the reply! I think I explained my problem poorly - I'll try
again;

I have an access point and 2 computers. One connected to the AP by
ethernet (PC0) and the other by wlan (PC1).

In order to simulate several clients in the wlan I multiplex the card of
PC1. The problem is that all frames sent from PC0 to the different
interfaces have the same MAC address.

I tried to change the MAC addresses in the ARP cache of PC0 such that
each IP has the intended MAC address (the one assigned to the
interface). But then the frames get all lost - I cannot even ping the
different interfaces of PC1 (except the primary interface as it still
has the same MAC).

> I'm guessing you're using the same IP subnet on all of them.
>
> You'll need to either tune IP routing
> (https://lwn.net/Articles/364318/) and/or force sockets to bind to
> interfaces (e.g. ping with "-I" parameter).
>
> Personally, I often use ipv6 link-local addresses to test traffic on
> such topologies to avoid the problem.

Correct me if I am wrong - but what you suggested is only needed if I
want to send data from the different interfaces to each other or send
from the different interfaces - right?

Thanks for the help

Kilian