This implements cfg80211's get_key() to allow retrieving the sequence
counter for a TKIP or CCMP key from userspace. It also cleans up and
documents the associated low-level driver interface.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are various decisions influencing the decision whether to buffer
a frame for after the next DTIM beacon. The "do we have stations in PS
mode" condition cannot be tested by the driver so mac80211 has to do
that. To ease driver writing for hardware that can buffer frames until
after the next DTIM beacon, introduce a new txctl flag telling the
driver to buffer a specific frame.
While at it, restructure and comment the code for multicast buffering
and remove spurious "inline" directives.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous patch left only one user of the ieee80211_is_eapol()
function and that user can be eliminated easily by introducing
a new "frame is EAPOL" flag to handle the frame specially (we
already have this information) instead of doing the (expensive)
ieee80211_is_eapol() all the time.
Also, allow unencrypted frames to be sent when they are injected.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This makes mac80211 include the low-level MAC timestamp
in the radiotap header if the driver indicated (by a new
RX flag) that the timestamp is valid.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch configures the 802.11n mode of operation
internally in ieee80211_conf structure and in the low-level
driver as well (through op conf_ht).
It does not include AP configuration flows.
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
New structures:
- ieee80211_ht_info: describing STA's HT capabilities
- ieee80211_ht_bss_info: describing BSS's HT characteristics
Changed structures:
- ieee80211_hw_mode: now also holds PHY HT capabilities for each HW mode
- ieee80211_conf: ht_conf holds current self HT configuration
ht_bss_conf holds current BSS HT configuration
- flag IEEE80211_CONF_SUPPORT_HT_MODE added to indicate if HT use is
desired
- sta_info: now also holds Peer's HT capabilities
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Interface iteration in mac80211 can be done without holding any
locks because I converted it to RCU. Initially, I thought this
wouldn't be needed for ieee80211_iterate_active_interfaces but
it's turning out that multi-BSS AP support can be much simpler
in a driver if ieee80211_iterate_active_interfaces can be called
without holding locks. This converts it to use RCU, it adds a
requirement that the callback it invokes cannot sleep.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sometimes drivers need to know which interfaces are associated with
their hardware. Rather than forcing those drivers to keep track of
the interfaces that were added, this adds an iteration function to
mac80211.
As it is intended to be used from the interface add/remove callbacks,
the iteration function may currently only be called under RTNL.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The driver operations set_ieee8021x(), set_port_auth() and
set_privacy_invoked() are not used by any drivers, except
set_privacy_invoked() they aren't even used by mac80211.
Remove them at least until we need to support drivers with
mac80211 that require getting this information.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This allows a driver to ask for a specific rate control algorithm.
The rate control algorithm asked for must be registered and be
available as a module or built-in.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds sta_notify callback and removes sta_table_notification
which was not used by any driver.
sta_notify() is essential for drivers that keeps notion of station
internally and need to be notified about removal or addition of a station
to the (I)BSS or assocation to an AP.
This version adds interface id to the parameter list
as suggested by Johannes Berg
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Many devices have LEDs to indicate the link status.
Export this functionality to drivers.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This "algorithm" is used only internally and is not useful.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Michael Buesch <mb@bu3sch.de>
Acked-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Removes the management interface since it is only required
for hostapd/userspace MLME, will not be in the final tree
at least in this form and hostapd/userspace MLME currently
do not work against this tree anyway.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since I cannot convince the lazy driver authors (hello Michael)
to stop (ab)using the MGMT interface type internally in their
drivers, this patch introduces a new _INVALID type especially
for their use and changes all affected drivers to use it.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is not useful since we do not support probe response
offload to hardware at this time and beacons are set in
another way.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The typedef is not required, we can just use "enum ieee80211_key_alg"
instead of "ieee80211_key_alg"
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
These inlines are generally useful, not just with mac80211.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch adds a lot more documentation (in kernel-doc format)
to include/net/mac80211.h
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently, hardware flags that drivers must set are not
documented well enough. Fix this.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch changes mac80211 to verify that VLAN interfaces
are valid and not bother drivers about them any more.
VLAN interfaces are now only valid when an AP interface
is up with the same MAC address, and are automatically
turned off when the AP interface is set down.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Jouni Malinen <j@w1.fi>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Drivers are currently supposed to keep track of monitor
interfaces if they allow so-called "hard" monitor, and
they are also supposed to keep track of multicast etc.
This patch changes that, replaces the set_multicast_list()
callback with a new configure_filter() callback that takes
filter flags (FIF_*) instead of interface flags (IFF_*).
For a driver, this means it should open the filter as much
as necessary to get all frames requested by the filter flags.
Accordingly, the filter flags are named "positively", e.g.
FIF_ALLMULTI.
Multicast filtering is a bit special in that drivers that
have no multicast address filters need to allow multicast
frames through when either the FIF_ALLMULTI flag is set or
when the mc_count value is positive.
At the same time, drivers are no longer notified about
monitor interfaces at all, this means they now need to
implement the start() and stop() callbacks and the new
change_filter_flags() callback. Also, the start()/stop()
ordering changed, start() is now called *before* any
add_interface() as it really should be, and stop() after
any remove_interface().
The patch also changes the behaviour of setting the bssid
to multicast for scanning when IEEE80211_HW_NO_PROBE_FILTERING
is set; the IEEE80211_HW_NO_PROBE_FILTERING flag is removed
and the filter flag FIF_BCN_PRBRESP_PROMISC introduced.
This is a lot more efficient for hardware like b43 that
supports it and other hardware can still set the BSSID
to all-ones.
Driver modifications by Johannes Berg (b43 & iwlwifi), Michael Wu
(rtl8187, adm8211, and p54), Larry Finger (b43legacy), and
Ivo van Doorn (rt2x00).
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This is unused.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add more mac80211 documentation.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The IEEE80211_CONF_SSID_HIDDEN setting is not useful for any driver
we have and should be a per-interface setting anyway. Remove it.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch allows drivers to indicate bad FCS/PLCP CRC to the stack and
have the stack drop packets like that except for monitor interfaces.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The TKIP mixing code was added for the benefit of Intel's ipw3945
chipset but that code ended up not using it. We have previously
identified many problems with this code and it crystallized that
library functions for mixing are likely to handle this in much
more generality and might allow b43 to take advantage of hardware
acceleration for TKIP.
Due to these reasons, remove the TKIP mixing for hardware
accelerated crypto operations.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Buesch <mb@bu3sch.de>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch makes the mac80211/driver interface rely only on the
IEEE80211_TXCTL_DO_NOT_ENCRYPT flag to signal to the driver whether
a frame should be encrypted or not, since mac80211 internally no
longer relies on HW_KEY_IDX_INVALID either this removes it, changes
the key index to be a u8 in all places and makes the full range of
the value available to drivers.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch formats some documentation in mac80211.h into kerneldoc
and also adds some more explanations for hardware crypto.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
No existing drivers use this callback, hence there's no telling
how it might be used. In fact, it is unlikely to be of much use
as-is because the default key index isn't something that the
driver can do much with without knowing which interface it was
for etc. And if it needs the key index for the transmitted frame,
it can get it by keeping a reference to the key_conf structure
and looking it up by hw_key_idx.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch reworks the various hardware crypto related
flags to make them more local, i.e. put them with each
key or each packet instead of into the hw struct.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes all mention of the atheros turbo modes that
can't possibly work properly anyway since in some places we don't
check for them when we should.
I have no idea what the iwlwifi drivers were doing with these but
it can't possibly have been correct.
Cc: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This moves all the key handling code out from ieee80211_ioctl.c
into key.c and also does the following changes including documentation
updates in mac80211.h:
1) Turn off hardware acceleration for keys when the interface
is down. This is necessary because otherwise monitor
interfaces could be decrypting frames for other interfaces
that are down at the moment. Also, it should go some way
towards better suspend/resume support, in any case the
routines used here could be used for that as well.
Additionally, this makes the driver interface nicer, keys
for a specific local MAC address are only ever present
while an interface with that MAC address is enabled.
2) Change driver set_key() callback interface to allow only
return values of -ENOSPC, -EOPNOTSUPP and 0, warn on all
other return values. This allows debugging the stack when
a driver notices it's handed a key while it is down.
3) Invert the flag meaning to KEY_FLAG_UPLOADED_TO_HARDWARE.
4) Remove REMOVE_ALL_KEYS command as it isn't used nor do we
want to use it, we'll use DISABLE_KEY for each key. It is
hard to use REMOVE_ALL_KEYS because we can handle multiple
virtual interfaces with different key configuration, so we'd
have to keep track of a lot of state for this and that isn't
worth it.
5) Warn when disabling a key fails, it musn't.
6) Remove IEEE80211_HW_NO_TKIP_WMM_HWACCEL in favour of per-key
IEEE80211_KEY_FLAG_WMM_STA to let driver sort it out itself.
7) Tell driver that a (non-WEP) key is used only for transmission
by using an all-zeroes station MAC address when configuring.
8) Change the set_key() callback to have access to the local MAC
address the key is being added for.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove the default_wep_only stuff, this wasn't really done well
and no current driver actually cares.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch embeds the struct ieee80211_key_conf into struct ieee80211_key
and thus avoids allocations and having data present twice.
This required some more changes:
1) The removal of the IEEE80211_KEY_DEFAULT_TX_KEY key flag.
This flag isn't used by drivers nor should it be since
we have a set_key_idx() callback. Maybe that callback needs
to be extended to include the key conf, but only a driver that
requires it will tell.
2) The removal of the IEEE80211_KEY_DEFAULT_WEP_ONLY key flag.
This flag is global, so it shouldn't be passed in the key
conf structure. Pass it to the function instead.
Also, this patch removes the AID parameter to the set_key() callback
because it is currently unused and the hardware currently cannot know
about the AID anyway. I suspect this was used with some hardware that
actually selected the AID itself, but that functionality was removed.
Additionally, I've removed the ALG_NULL key algorithm since we have
ALG_NONE.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ioctls
* PRISM2_PARAM_RADAR_DETECT
* PRISM2_PARAM_SPECTRUM_MGMT
are not used by hostapd or wpa_supplicant,
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ioctls
* PRISM2_PARAM_STA_ANTENNA_SEL
* PRISM2_PARAM_TX_POWER_REDUCTION
* PRISM2_PARAM_DEFAULT_WEP_ONLY
are not used by hostapd or wpa_supplicant.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ioctls
* PRISM2_PARAM_ANTENNA_MODE
* PRISM2_PARAM_STAT_TIME
are not used by hostapd or wpa_supplicant.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When doing key selection for software decryption, mac80211 gets
a few things wrong: it always uses pairwise keys if configured,
even if the frame is addressed to a multicast address. Also, it
doesn't allow using a key index of zero if a pairwise key has
also been found.
This patch changes the key selection code to be (more) in line
with the 802.11 specification. I have confirmed that with this,
multicast frames are correctly decrypted and I've tested with
WEP as well.
While at it, I've cleaned up the semantics of the hardware flags
IEEE80211_HW_WEP_INCLUDE_IV and IEEE80211_HW_DEVICE_HIDES_WEP
and clarified them in the mac80211.h header; it is also now
allowed to set the IEEE80211_HW_DEVICE_HIDES_WEP option even if
it only applies to frames that have been decrypted by the hw,
unencrypted frames must be dropped but encrypted frames that
the hardware couldn't handle can be passed up unmodified.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Unused in drivers, userspace and mac80211.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The flag is never checked because drivers can simply call
ieee80211_beacon_get() regardless of setting this flag.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The callback isn't used so remove it.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
zd1211rw and bcm43xx are interested in being notified when ERP IE conditions
change, so that they can reprogram a register which affects how control frames
are transmitted.
This patch adds an interface similar to the one that can be found in softmac.
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Similarly to CTS protection, whether short preambles are used for 802.11b
transmissions should be a per-subif setting, not device global.
For STAs, this patch makes short preamble handling automatic based on the ERP
IE. For APs, hostapd still uses the prism ioctls, but the write ioctl has been
restricted to AP-only subifs.
ieee80211_txrx_data.short_preamble (an unused field) was removed.
Unfortunately, some API changes were required for the following functions:
- ieee80211_generic_frame_duration
- ieee80211_rts_duration
- ieee80211_ctstoself_duration
- ieee80211_rts_get
- ieee80211_ctstoself_get
Affected drivers were updated accordingly.
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
mac80211 informs the driver what the short and long retry values are through
set_retry_limit(), but when packets are being transmitted it did not inform the
driver which of the 2 retry limits should actually be used.
Instead it sends the actual value, but for drivers that can only set the retry limit
and the register and in the descriptor need to indicate which of the limits should
be used this is not really useful.
This patch will add a IEEE80211_TXCTL_LONG_RETRY_LIMIT flag to the
ieee80211_tx_control structure. By default the short retry limit should be
used but if the flag is set the long retry should be used.
This does not prevent the driver to ignore the request for "no retry" packets,
but at least those will be send out with the short retry limit. But there is no
perfect cure for this problem.. :(
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The sta_info code has some awkward locking which prevents some driver
callbacks from being allowed to sleep. This patch makes the locking more
focused so code that calls driver callbacks are allowed to sleep. It also
converts sta_lock to a rwlock.
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The semantics of not having an add_interface callback are not well
defined, this callback is required because otherwise you cannot obtain
the requested MAC address of the device. Change the documentation to
reflect this, add a note about having no MAC address at all, add a
warning that mac_addr in struct ieee80211_if_init_conf can be NULL and
finally verify that a few callbacks are assigned by way of BUG_ON()
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Johannes Berg