Using wlan0 as network interface doesn't work

[Moritz Lang]

I try to connect a Raspberry via iWLAN to my PLC using p-net. When using eth0, everything works fine, but when using wlan0 p-net won't establish a connection. I debugged the problem and found that p-net is indirectly calling ethtool to determine the connection type, which only supports cable based connections.
Specifically, the call stack is

• pnal_eth_get_status
• pf_pdport_update_eth_status
• bg_worker_task

In pnal_eth_get_status (pnal.c), we finally hafe the condition

if(ioctl(control_socket, SIOCETHTOOL, &ifr) >= 0)
{..}

which evaluates to false when ifr.ifr_name is "wlan0" and causes the problem.

When I (just out of curiousity) hard-coded the following else-statement

if(ioctl(control_socket, SIOCETHTOOL, &ifr) >= 0)
{..}
else
{
  status->is_autonegotiation_enabled = true;
  status->is_autonegotiation_supported = true;
  status->operational_mau_type = PNAL_ETH_MAU_COPPER_100BaseTX_FULL_DUPLEX;
  status->autonegotiation_advertised_capabilities = PNAL_ETH_AUTONEG_CAP_UNKNOWN;
  ret = 0;
}

p-net runs without problems and I can establish the connection to the PLC via iWLAN. Using PNAL_ETH_MAU_RADIO instead however not works, since this results in p-net believing my network speed is too low. Specifically, in pf_cmdev.c,

if(pf_cmdev_check_pvdev(net) == 0)
{..}

evaluates to false.

Is there a way to add iWLAN support to p-net? From the outside, the problem seems to only/mainly be the call to ethtool which doesn't support WLAN network interfaces (and maybe pf_cmdev_check_pvdev ranking PNAL_ETH_MAU_RADIO to be slower than PNAL_ETH_MAU_COPPER_100BaseTX_FULL_DUPLEX)? Or do you know a way to trick ethtool to believe that wlan0 is cable based?

Thanks a lot!
Moritz