Why does WimaxNetDevice::SupportsSendFrom return false

[Red zhaoyj]

Hi,

I am trying to add wimax net device to bridge. But I got an Error that wimax net devices don't support SendFrom.

After I checked wimax-net-deivce.cc, I find that the value returned by WimaxNetDevice::SupportsSendFrom is false.

On the other hand, I find that WimaxNetDevice does contain a member function whose name is SendFrom.

I am curious why wimax net device doesn't support SendFrom while it has member function SendFrom.

And I also wonder if I can modify the value returned by WimaxNetDevice::SupportsSendFrom to be true.

Would you please help with these? Thank you very much in advance.

Bests,

[Tommaso Pecorella]

Hi,

I have no idea why it's not supporting SendFrom.

From a theoretic point of view, SupportsSendFrom should return false when you can not "inject" a packet with a fake source MAC address in the network without making it go boom.

Aka, in Wi-Fi, you can send a packet with a forged source MAC address, the AP will not burn.

In WiMAX things are a bit different, as stations are granted uplink slots by the BS. As a consequence, the BS knows who's transmitting, even if the MAC is wrong. Well, except for the contention slots in the frame. Anyway.

I'm not sure that you can use SendFrom without having the BS go fishin'. The only thing to do is... try.

Hope this helps,

T.

[Red zhaoyj]

Hi Mr Tommaso Pecorella,

Thank you very much for your reply, especially for telling me what kind of net device supports SendFrom.

Besides, I have tried my idea and unsurprisingly ss is unable to send packets out.

Perhaps more modification is needed in order to add wimax net device to a bridge. However it is too difficult for me.

>_< Anyway, thank you very much, sir !

Bests,

Tommaso Pecorella於 2015年4月3日星期五 UTC+8上午1時02分07秒寫道：