Hello!
I have applied a patch that is based on a long discussion by private
e-mail (unfortunately - I'd rather see such discussions in the mailing
list). The problem is described by John Denker here:
http://www.av8n.com/computer/wifi-lagoon.html
It's a long article, so let me just summarize its main points here:
1) Station to station packets are relayed by the AP. The packet is
transmitted twice on the same medium.
2) Some (or even all) firmwares we support would receive both packets when
in promiscuous mode.
3) Both packets would look identical once they are decapsulated, so
applications would get duplicate packets.
4) Duplicate packets are bad, especially for applications that simply want
their data transmitted (as opposed to sniffers).
David Gibson has suggested that the uplink packets (i.e. the packets that
the AP is supposed to receive physically) are marked by setting
skb->pkt_type to PACKET_OTHERHOST, which would hide them from applications
that don't use promiscuous mode.
Since the uplink packets can only be identified by the ToDS flag in the
802.11 headers, it was decided to start using the 802.11 headers for
received packets, rather than the compatibility 802.3 headers constructed
by the firmware.
The 802.11 header is already used in monitor mode, so the patch unifies
some code and allows further unification. I avoided some trivial changes
to keep the patch readable.
The patch has been applied to all branches. Please test.
--
Regards,
Pavel Roskin
rx802_11.diff
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