Commit Graph

19 Commits

Author SHA1 Message Date
Pavel Roskin 8c6c03fe23 rc80211_minstrel: fix contention window calculation
The contention window is supposed to be a power of two minus one, i.e.
15, 31, 63, 127...  minstrel_rate_init() forgets to subtract 1, so the
sequence becomes 15, 32, 66, 134...

Bug reported by Dan Halperin <dhalperi@cs.washington.edu>

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-09-16 16:21:00 -04:00
Javier Cardona bfc32e6a95 mac80211: Decouple fail_avg stats used by mesh from rate control algorithm.
Mesh uses the tx failure average to compute the (m)path metric.  This used to
be done inside the rate control module.  This patch breaks the dependency
between the mesh stack and the rate control algorithm.  Mesh will now work
independently of the chosen rate control algorithm.

The mesh stack keeps a moving average of the average transmission losses for
each mesh peer station.  If the fail average exceeds a certain threshold, the
peer link is marked as broken.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-20 11:36:02 -04:00
Javier Cardona 5815814bfa mac80211: Early detection of broken mesh paths when using minstrel.
This change triggers a path discovery as soon as the link quality degrades
below a certain threshold.  This results in a faster path recovery time than
by simply relying on the periodic path refresh mechanism to detect broken
links.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-14 09:14:01 -04:00
Javier Cardona d403a1c66e mac80211: Update the station failed frames average when minstrel is used.
The fail_avg value is used to compute the mesh metric, and was only being set
by the pid rate control module. This fixes the mesh path selection mechanism
for cards that use mistrel for rate control.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-14 09:14:00 -04:00
Luis R. Rodriguez 4c6d4f5c33 mac80211: add helper for management / no-ack frame rate decision
All current rate control algorithms agree to send management and no-ack
frames at the lowest rate. They also agree to do this when sta
and the private rate control data is NULL. We add a hlper to mac80211
for this and simplify the rate control algorithm code.

Developers wishing to make enhancements to rate control algorithms
are for broadcast/multicast can opt to not use this in their
gate_rate() mac80211 callback.

Cc: Zhu Yi <yi.zhu@intel.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: ipw3945-devel@lists.sourceforge.net
Cc: Gabor Juhos <juhosg@openwrt.org>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Cc: Derek Smithies <derek@indranet.co.nz>
Cc: Chittajit Mitra <Chittajit.Mitra@Atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-07-24 15:05:16 -04:00
Luis R. Rodriguez e898643658 mac80211: make minstrel/pid RC use ieee80211_is_data(fc)
Cc: Felix Fietkau <nbd@openwrt.org>
Cc: Derek Smithies <derek@indranet.co.nz>
Cc: Chittajit Mitra <Chittajit.Mitra@Atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-07-24 15:05:16 -04:00
Luciano Coelho 3938b45c1c mac80211: minstrel: avoid accessing negative indices in rix_to_ndx()
If rix is not found in mi->r[], i will become -1 after the loop.  This value
is eventually used to access arrays, so we were accessing arrays with a
negative index, which is obviously not what we want to do.  This patch fixes
this potential problem.

Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-07-07 12:55:28 -04:00
Bob Copeland 5ee58d7e6a mac80211: fix minstrel single-rate memory corruption
The minstrel rate controller periodically looks up rate indexes in
a sampling table.  When accessing a specific row and column, minstrel
correctly does a bounds check which, on the surface, appears to handle
the case where mi->n_rates < 2.  However, mi->sample_idx is actually
defined as an unsigned, so the right hand side is taken to be a huge
positive number when negative, and the check will always fail.

Consequently, the RC will overrun the array and cause random memory
corruption when communicating with a peer that has only a single rate.
The max value of mi->sample_idx is around 25 so casting to int should
have no ill effects.

Without the change, uptime is a few minutes under load with an AP
that has a single hard-coded rate, and both the AP and STA could
potentially crash.  With the change, both lasted 12 hours with a
steady load.

Thanks to Ognjen Maric for providing the single-rate clue so I could
reproduce this.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=12490 on the
regression list (also http://bugzilla.kernel.org/show_bug.cgi?id=13000).

Cc: stable@kernel.org
Reported-by: Sergey S. Kostyliov <rathamahata@gmail.com>
Reported-by: Ognjen Maric <ognjen.maric@gmail.com>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-06-10 13:27:51 -04:00
David S. Miller bb803cfbec Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/scsi/fcoe/fcoe.c
2009-05-18 21:08:20 -07:00
John W. Linville 621ad7c96a mac80211: avoid NULL ptr deref when finding max_rates in PID and minstrel
"There is another problem with this piece of code. The sband will be NULL
after second iteration on single band device and cause null pointer
dereference. Everything is working with dual band card. Sorry, but i
don't know how to explain this clearly in English. I have looked on the
second patch for pid algorithm and found similar bug."

Reported-by: Karol Szuster <qflon@o2.pl>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-05-11 15:07:01 -04:00
David S. Miller a8679be207 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 2009-05-08 12:46:17 -07:00
Gábor Stefanik 4edf040afc mac80211: Fix handling of retry count of NO_ACK frames in minstrel
Make the retry count zero (total try count = 1) for frames with
IEEE80211_TX_CTL_NO_ACK set.

Also remove the check for is_multicast_ether_addr in use_low_rate,
which is redundant because all multicasts have IEEE80211_TX_CTL_NO_ACK
set.

Signed-off-by: Gábor Stefanik <netrolller.3d@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-05-06 15:14:50 -04:00
Jiri Slaby 8e53217527 mac80211: minstrel, fix memory corruption
minstrel doesn't count max rate count in fact, since it doesn't use
a loop variable `i' and hence allocs space only for bitrates found in
the first band.

Fix it by involving the `i' as an index so that it traverses all the
bands now and finds the real max bitrate count.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-05-04 16:22:15 -04:00
Christian Lamparter d57854bb1d minstrel: fix warning if lowest supported rate index is not 0
This patch fixes the following WARNING (caused by rix_to_ndx): "
>WARNING: at net/mac80211/rc80211_minstrel.c:69 minstrel_rate_init+0xd2/0x33a [mac80211]()
>[...]
>Call Trace:
> warn_on_slowpath+0x51/0x75
> _format_mac_addr+0x4c/0x88
> minstrel_rate_init+0xd2/0x33a [mac80211]
> print_mac+0x16/0x1b
> schedule_hrtimeout_range+0xdc/0x107
> ieee80211_add_station+0x158/0x1bd [mac80211]
> nl80211_new_station+0x1b3/0x20b [cfg80211]

The reason is that I'm experimenting with "g" only mode on a 802.11 b/g card.

Therefore rate_lowest_index returns 4 (= 6Mbit, instead of usual 0 = 1Mbit).
Since mi->r array is initialized with zeros in minstrel_alloc_sta,
rix_to_ndx has a hard time to find the 6Mbit entry and will trigged the WARNING.

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-01-12 14:24:55 -05:00
Johannes Berg 2df78167ad wireless: fix a few sparse warnings
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-11-10 15:10:17 -05:00
Johannes Berg 50fb2e4572 mac80211: remove rate_control_clear
"Clearing" the rate control algorithm is pointless, none of
the algorithms actually uses this operation and it's not even
invoked properly for all channel switching. Also, there's no
need to since rate control algorithms work per station.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-10-31 19:00:37 -04:00
Felix Fietkau f4a8cd94fc minstrel: improve performance for non-MRR drivers
This patch enhances minstrel's performance for non-MRR setups,
by preventing it from sampling slower rates with >95% success
probability and by putting at least 1 non-sample frame between
several sample frames.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-10-31 19:00:36 -04:00
Johannes Berg e6a9854b05 mac80211/drivers: rewrite the rate control API
So after the previous changes we were still unhappy with how
convoluted the API is and decided to make things simpler for
everybody. This completely changes the rate control API, now
taking into account 802.11n with MCS rates and more control,
most drivers don't support that though.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-10-31 19:00:23 -04:00
Felix Fietkau cccf129f82 mac80211: add the 'minstrel' rate control algorithm
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-10-06 18:14:57 -04:00