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Thu May 10 15:10:22 EDT 2012


I should work on the Linux kernel responsible for packets routing. Please
correct me if I'm wrong.
Thanks you very much.





2013/1/31 Arend van Spriel <arend at broadcom.com>

> On 01/30/2013 08:34 PM, Sergey Ryazanov wrote:
> > 2013/1/30 Chun Chien <johnyluyte at gmail.com>:
> >> I used a Laptop running hostapd, with wired Internet connection eth0 a=
nd
> >> wireless interface wlan2. And I used a android phone to connect to the
> >> Internet via hostapd running on the laptop.
> >>
> >> I supposed that the packets sent from the phone to the Internet should
> go
> >> through the following path.
> >> Phone WiFi interface -> wlan2 of laptop -> Hostapd running on laptop -=
>
> eth0
> >> of laptop -> The Internet
> >> Is this correct?
> >>
> > Actually _data_ packets are never go through the hostapd. Hostapd acts
> > as AP manager: constructs beacon frames, handle client
> > association/authentication process, etc. Data packets travel as usual
> > through the bridging or through the routing kernel subsystem. Wireless
> > stack or driver inside the kernel is responsible for frame format
> > conversion.
> > If you use bridge, then packets go through the following path: wlan2
> > -> (bridge) -> eth0.
> > If your access point act as router, then packets go though then
> > following path: wlan2 -> (IP router) -> eth0.
> > So, if you need capture _data_ traffic from the phone then simply run
> > wireshark on the wlan2 interface.
>
> hostapd may not support it, but there is wlantest which I think could do
> that. Whether that is useful probably depends on what you actually want
> to do with those packets.
>
> Gr. AvS
>
> > --
> > BR,
> > Sergey
> > _______________________________________________
> > HostAP mailing list
> > HostAP at lists.shmoo.com
> > http://lists.shmoo.com/mailman/listinfo/hostap
> >
>
>
>


--=20
Best Regards
--
=C2=B2=B8s Chun Chien
0972-711192
Wireless Internet Research and Engineering Laboratory,
Department of Computer Science, NCTU.

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<div dir=3D"ltr">Thanks you both for the fast replies. The explanation is v=
ery clear and easy to understand. :)<div>No wonder there are lots of&nbsp;<=
span style=3D"font-family:arial,sans-serif;font-size:17.600000381469727px">=
beacon&nbsp;frames in driver_xxxxx.c</span><br>
<div>I&#39;m using&nbsp;NAT with DHCP so its an IP router in my case.</div>=
<div><br></div><div style>From my understanding, If I were to modify the pa=
ckets from wlan2 to eth0, I should work on the Linux kernel responsible for=
 packets routing.&nbsp;<span style=3D"font-family:arial,sans-serif">Please =
correct me if I&#39;m wrong.</span></div>
<div><div style>Thanks you very much.</div></div><div><br></div><div><br></=
div><div><br></div></div></div><div class=3D"gmail_extra"><br><br><div clas=
s=3D"gmail_quote">2013/1/31 Arend van Spriel <span dir=3D"ltr">&lt;<a href=
=3D"mailto:arend at broadcom.com" target=3D"_blank">arend at broadcom.com</a>&gt;=
</span><br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div class=3D"HOEnZb"><div class=3D"h5">On 0=
1/30/2013 08:34 PM, Sergey Ryazanov wrote:<br>
&gt; 2013/1/30 Chun Chien &lt;<a href=3D"mailto:johnyluyte at gmail.com">johny=
luyte at gmail.com</a>&gt;:<br>
&gt;&gt; I used a Laptop running hostapd, with wired Internet connection et=
h0 and<br>
&gt;&gt; wireless interface wlan2. And I used a android phone to connect to=
 the<br>
&gt;&gt; Internet via hostapd running on the laptop.<br>
&gt;&gt;<br>
&gt;&gt; I supposed that the packets sent from the phone to the Internet sh=
ould go<br>
&gt;&gt; through the following path.<br>
&gt;&gt; Phone WiFi interface -&gt; wlan2 of laptop -&gt; Hostapd running o=
n laptop -&gt; eth0<br>
&gt;&gt; of laptop -&gt; The Internet<br>
&gt;&gt; Is this correct?<br>
&gt;&gt;<br>
&gt; Actually _data_ packets are never go through the hostapd. Hostapd acts=
<br>
&gt; as AP manager: constructs beacon frames, handle client<br>
&gt; association/authentication process, etc. Data packets travel as usual<=
br>
&gt; through the bridging or through the routing kernel subsystem. Wireless=
<br>
&gt; stack or driver inside the kernel is responsible for frame format<br>
&gt; conversion.<br>
&gt; If you use bridge, then packets go through the following path: wlan2<b=
r>
&gt; -&gt; (bridge) -&gt; eth0.<br>
&gt; If your access point act as router, then packets go though then<br>
&gt; following path: wlan2 -&gt; (IP router) -&gt; eth0.<br>
&gt; So, if you need capture _data_ traffic from the phone then simply run<=
br>
&gt; wireshark on the wlan2 interface.<br>
<br>
</div></div>hostapd may not support it, but there is wlantest which I think=
 could do<br>
that. Whether that is useful probably depends on what you actually want<br>
to do with those packets.<br>
<br>
Gr. AvS<br>
<span class=3D"HOEnZb"><font color=3D"#888888"><br>
&gt; --<br>
&gt; BR,<br>
&gt; Sergey<br>
&gt; _______________________________________________<br>
&gt; HostAP mailing list<br>
&gt; <a href=3D"mailto:HostAP at lists.shmoo.com">HostAP at lists.shmoo.com</a><b=
r>
&gt; <a href=3D"http://lists.shmoo.com/mailman/listinfo/hostap" target=3D"_=
blank">http://lists.shmoo.com/mailman/listinfo/hostap</a><br>
&gt;<br>
<br>
<br>
</font></span></blockquote></div><br><br clear=3D"all"><div><br></div>-- <b=
r><div dir=3D"ltr">Best Regards <br>--<br>=C2=B2=B8s Chun Chien<br>0972-711=
192<br>Wireless Internet Research and Engineering Laboratory,<br>Department=
 of Computer Science, NCTU.<br>
</div>
</div>

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