Linux already supports 802.11h, where the access point can tell the
client to reduce its transmission power. However, 802.11h is only
defined for 5 GHz, where the need for this is much smaller than on
2.4 GHz.

Cisco has their own solution, called DTPC (Dynamic Transmit Power
Control). Cisco APs on a controller sometimes but not always send
802.11h; they always send DTPC, even on 2.4 GHz. This patch adds support
for parsing and honoring the DTPC IE in addition to the 802.11h
element (they do not always contain the same limits, so both must
be honored); the format is not documented, but very simple.

Tested (on top of wireless.git and on 3.16.1) against a Cisco Aironet
1142 joined to a Cisco 2504 WLC, by setting various transmit power
levels for the given access points and observing the results.
The Wireshark 802.11 dissector agrees with the interpretation of the
element, except for negative numbers, which seem to never happen
anyway.
Signed-off-by: NSteinar H. Gunderson <sgunderson@bigfoot.com>
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>

Decouple the logic of parsing the 802.11d and 802.11h IEs from the
part of deciding what to do about the data (messaging, clamping to
0 dBm, doing the actual setting). This paves the way for the next
patch, which introduces more data sources for transmit power limitation.
Signed-off-by: NSteinar H. Gunderson <sgunderson@bigfoot.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

commit "mac80211: disable 40MHz support in case of 20MHz AP"
broke working VHT in 20Mhz with APs like Netgear R6300v2 which
do not publish support for 40Mhz but allow use of VHT in 20Mhz.
The break is because VHT is disabled once no HT cap doesn't indicate
support for 40Mhz. This causes the assoc request to be sent without
any VHT IE and the association is only HT due to this.

For more details check out commit 4a817aa7
"mac80211: allow VHT with peers not capable of 40MHz"

Fixes: 53b954ee ("mac80211: disable 40MHz support in case of 20MHz AP")
Signed-off-by: NEyal Shapira <eyalx.shapira@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Extend mac80211 set_coverage_class API in order to enable ACK timeout
estimation algorithm (dynack) passing coverage class equals to -1
to lower drivers. Synchronize set_coverage_class routine signature with
mac80211 function pointer for p54, ath9k, ath9k_htc and ath5k drivers.
Signed-off-by: NLorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Enable ACK timeout estimation algorithm (dynack) using mac80211
set_coverage_class API. Dynack is activated passing coverage class equals to -1
to lower drivers and it is automatically disabled setting valid value for
coverage class.
Define NL80211_ATTR_WIPHY_DYN_ACK flag attribute to enable dynack from
userspace. In order to activate dynack NL80211_FEATURE_ACKTO_ESTIMATION feature
flag must be set by lower drivers to indicate dynack capability.
Signed-off-by: NLorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

If the remaining time in the current roc is not long
enough, mac80211 adds the new roc right after it
(if they have similar params).

However, in case of multiple rocs, the "next roc"
is not considered, resulting in multiple rocs,
each one with its own duration.

Refactor the code a bit and consider the next roc,
so a single max roc will be used instead of
multiple rocs (which might last much longer).
Signed-off-by: NEliad Peller <eliadx.peller@intel.com>
Reviewed-by: NIlan Peer <ilan.peer@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The new duration (remaining duration after the current
ROC ends) was calculated but not used, making the
optimization worthless.
Signed-off-by: NEliad Peller <eliadx.peller@intel.com>
Reviewed-by: NIlan Peer <ilan.peer@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The regdom intersection code simply tries intersecting
each rule of the source with each rule of the target.

Since the resulting intersections are not observed
as a whole, this can result in multiple overlapping/duplicate
entries.

Make the rule addition a bit more smarter, by looking
for rules that can be contained within other rules,
and adding only extended ones.
Signed-off-by: NEliad Peller <eliad@wizery.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

In case of a RRM-supporting connection, in the association request
frame: set the RRM capability flag, and add the required IEs.
Signed-off-by: NAssaf Krauss <assaf.krauss@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Add a flag attribute to use in associations, for tagging the target
connection as supporting RRM. It is the responsibility of upper
layers to set this flag only if both the underlying device, and the
target network indeed support RRM.
To be used in ASSOCIATE and CONNECT commands.
Signed-off-by: NAssaf Krauss <assaf.krauss@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The function description claimed that on error the skb isn't
freed even though it is, and stated return values that are
different than what really happens in the code.
Signed-off-by: NLiad Kaufman <liad.kaufman@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Our legal structure changed at some point (see wikipedia), but
we forgot to immediately switch over to the new copyright
notice.

For files that we have modified in the time since the change,
add the proper copyright notice now.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Our legal structure changed at some point (see wikipedia), but
we forgot to immediately switch over to the new copyright
notice.

For files that we have modified in the time since the change,
add the proper copyright notice now.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Not sure how the declaration of ieee80211_tdls_peer_del_work
landed after the double inclusion protection end.
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When starting an offloaded BA session it is
unknown what starting sequence number should be
used. Using last_seq worked in most cases except
after hw restart.

When hw restart is requested last_seq is
(rightfully so) kept unmodified. This ended up
with BA sessions being restarted with an aribtrary
BA window values resulting in dropped frames until
sequence numbers caught up.

Instead of last_seq pick seqno of a first Rxed
frame of a given BA session.

This fixes stalled traffic after hw restart with
offloaded BA sessions (currently only ath10k).
Signed-off-by: NMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This adds one more ACPI ID of a Broadcom bluetooth chip.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When a device driver is unloaded local->interfaces
list is cleared. If there was more than 1
interface running and connected (bound to a
chanctx) then chantype recalc was called and it
ended up with compat being NULL causing a call
trace warning.

Warn if compat becomes NULL as a result of
incompatible bss_conf.chandef of interfaces bound
to a given channel context only.

The call trace looked like this:

 WARNING: CPU: 2 PID: 2594 at /devel/src/linux/net/mac80211/chan.c:557 ieee80211_recalc_chanctx_chantype+0x2cd/0x2e0()
 Modules linked in: ath10k_pci(-) ath10k_core ath
 CPU: 2 PID: 2594 Comm: rmmod Tainted: G        W     3.16.0-rc1+ #150
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  0000000000000009 ffff88001ea279c0 ffffffff818dfa93 0000000000000000
  ffff88001ea279f8 ffffffff810514a8 ffff88001ce09cd0 ffff88001e03cc58
  0000000000000000 ffff88001ce08840 ffff88001ce09cd0 ffff88001ea27a08
 Call Trace:
  [<ffffffff818dfa93>] dump_stack+0x4d/0x66
  [<ffffffff810514a8>] warn_slowpath_common+0x78/0xa0
  [<ffffffff81051585>] warn_slowpath_null+0x15/0x20
  [<ffffffff818a407d>] ieee80211_recalc_chanctx_chantype+0x2cd/0x2e0
  [<ffffffff818a3dda>] ? ieee80211_recalc_chanctx_chantype+0x2a/0x2e0
  [<ffffffff818a4919>] ieee80211_assign_vif_chanctx+0x1a9/0x770
  [<ffffffff818a6220>] __ieee80211_vif_release_channel+0x70/0x130
  [<ffffffff818a6dd3>] ieee80211_vif_release_channel+0x43/0xb0
  [<ffffffff81885f4e>] ieee80211_stop_ap+0x21e/0x5a0
  [<ffffffff8184b9b5>] __cfg80211_stop_ap+0x85/0x520
  [<ffffffff8181c188>] __cfg80211_leave+0x68/0x120
  [<ffffffff8181c268>] cfg80211_leave+0x28/0x40
  [<ffffffff8181c5f3>] cfg80211_netdev_notifier_call+0x373/0x6b0
  [<ffffffff8107f965>] notifier_call_chain+0x55/0x110
  [<ffffffff8107fa41>] raw_notifier_call_chain+0x11/0x20
  [<ffffffff816a8dc0>] call_netdevice_notifiers_info+0x30/0x60
  [<ffffffff816a8eb9>] __dev_close_many+0x59/0xf0
  [<ffffffff816a9021>] dev_close_many+0x81/0x120
  [<ffffffff816aa1c5>] rollback_registered_many+0x115/0x2a0
  [<ffffffff816aa3a6>] unregister_netdevice_many+0x16/0xa0
  [<ffffffff8187d841>] ieee80211_remove_interfaces+0x121/0x1b0
  [<ffffffff8185e0e6>] ieee80211_unregister_hw+0x56/0x110
  [<ffffffffa0011ac4>] ath10k_mac_unregister+0x14/0x60 [ath10k_core]
  [<ffffffffa0014fe7>] ath10k_core_unregister+0x27/0x40 [ath10k_core]
  [<ffffffffa003b1f4>] ath10k_pci_remove+0x44/0xa0 [ath10k_pci]
  [<ffffffff81373138>] pci_device_remove+0x28/0x60
  [<ffffffff814cb534>] __device_release_driver+0x64/0xd0
  [<ffffffff814cbcc8>] driver_detach+0xb8/0xc0
  [<ffffffff814cb23a>] bus_remove_driver+0x4a/0xb0
  [<ffffffff814cc697>] driver_unregister+0x27/0x50
Signed-off-by: NMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The "rcu_dereference()" calls are used directly in conditions.
Since their return values are never dereferenced it is recommended to
use "rcu_access_pointer()" instead of "rcu_dereference()".
Therefore, this patch makes the replacements.

The following Coccinelle semantic patch was used:
@@
@@

(
 if(
 (<+...
- rcu_dereference
+ rcu_access_pointer
  (...)
  ...+>)) {...}
|
 while(
 (<+...
- rcu_dereference
+ rcu_access_pointer
  (...)
  ...+>)) {...}
)
Signed-off-by: NAndreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1.   This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.

The following Coccinelle semantic patch was used:
@@
@@

- rcu_assign_pointer
+ RCU_INIT_POINTER
  (..., NULL)
Signed-off-by: NAndreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When using the cfg80211_inform_bss[_width]() functions drivers
cannot currently indicate whether the data was received in a
beacon or probe response. Fix that by passing a new enum that
indicates such (or unknown).

For good measure, use it in ath6kl.

Acked-by: Kalle Valo <kvalo@qca.qualcomm.com> [ath6kl]
Acked-by: Arend van Spriel <arend@broadcom.com> [brcmfmac]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

There are a few possible cases of where BSS data came from:
 1) only a beacon has been received
 2) only a probe response has been received
 3) the driver didn't report what it received (this happens when
    using cfg80211_inform_bss[_width]())
 4) both probe response and beacon data has been received

Unfortunately, in the userspace API, a few things weren't there:
 a) there was no way to differentiate cases 1) and 4) above
    without comparing the data of the IEs
 b) the TSF was always from the last frame, instead of being
    exposed for beacon/probe response separately like IEs

Fix this by
   i) exporting a new flag attribute that indicates whether or
      not probe response data has been received - this addresses (a)
  ii) exporting a BEACON_TSF attribute that holds the beacon's TSF
      if a beacon has been received
 iii) not exporting the beacon attributes in case (3) above as that
      would just lead userspace into thinking the data actually came
      from a beacon when that isn't clear

To implement this, track inside the IEs struct whether or not it
(definitely) came from a beacon.

Reported-by: William Seto
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This reverts commit dda444d5.

Channel switching code has been reworked and
improved significantly since the time original
locking issues were found.
Signed-off-by: NMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Header-less cloned skbs with sufficient headroom need not be cloned
unless the tailroom is going to be modified.

Fix ieee80211_skb_resize so it would only resize cloned skbs if either
the header isn't released or the tailroom is going to be modified.

Some drivers might have assumed that skbs are never cloned, so add a HW
flag that explicitly permits cloned TX skbs. Drivers which do not modify
TX skbs should set this flag to avoid copying skbs.
Signed-off-by: NIdo Yariv <idox.yariv@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When hw acceleration is enabled, the GENERATE_IV or PUT_IV_SPACE flags
will only require headroom space. Consequently, the tailroom-needed
counter can safely be decremented.
Signed-off-by: NIdo Yariv <idox.yariv@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

In the cfg80211_rx_mgmt(), parameter @gfp was used for the memory allocation.
But, memory get allocated under spin_lock_bh(), this implies atomic context.
So, one can't use GFP_KERNEL, only variants with no __GFP_WAIT. Actually, in all
occurrences GFP_ATOMIC is used (wil6210 use GFP_KERNEL by mistake),
and it should be this way or warning triggered in the memory allocation code.

Remove @gfp parameter as no actual choice exist, and use hard coded
GFP_ATOMIC for memory allocation.
Signed-off-by: NVladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Reorder some code to make ieee80211_vif_use_reserved_switch()
static, no other changes.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Use get_unaligned_le16 to access llid/plid.
Signed-off-by: NBob Copeland <me@bobcopeland.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

If the AP only advertises support for 20MHz (in the
ht operation ie), disable 40MHz and VHT.

This can improve interoperability with APs that
don't like stations exceeding their own
advertised capabilities.
Signed-off-by: NEliad Peller <eliadx.peller@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

We currently track the QoS capability twice: for all peer stations
in the WLAN_STA_WME flag, and for any clients associated to an AP
interface separately for drivers in the sta->sta.wme field.

Remove the WLAN_STA_WME flag and track the capability only in the
driver-visible field, getting rid of the limitation that the field
is only valid in AP mode.
Reviewed-by: NArik Nemtsov <arik@wizery.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Silences the following sparse warnings:
net/netlink/af_netlink.c:2926:21: warning: context imbalance in 'netlink_seq_start' - wrong count at exit
net/netlink/af_netlink.c:2972:13: warning: context imbalance in 'netlink_seq_stop' - unexpected unlock
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix TCP FRTO logic so that it always notices when snd_una advances,
indicating that any RTO after that point will be a new and distinct
loss episode.

Previously there was a very specific sequence that could cause FRTO to
fail to notice a new loss episode had started:

(1) RTO timer fires, enter FRTO and retransmit packet 1 in write queue
(2) receiver ACKs packet 1
(3) FRTO sends 2 more packets
(4) RTO timer fires again (should start a new loss episode)

The problem was in step (3) above, where tcp_process_loss() returned
early (in the spot marked "Step 2.b"), so that it never got to the
logic to clear icsk_retransmits. Thus icsk_retransmits stayed
non-zero. Thus in step (4) tcp_enter_loss() would see the non-zero
icsk_retransmits, decide that this RTO is not a new episode, and
decide not to cut ssthresh and remember the current cwnd and ssthresh
for undo.

There were two main consequences to the bug that we have
observed. First, ssthresh was not decreased in step (4). Second, when
there was a series of such FRTO (1-4) sequences that happened to be
followed by an FRTO undo, we would restore the cwnd and ssthresh from
before the entire series started (instead of the cwnd and ssthresh
from before the most recent RTO). This could result in cwnd and
ssthresh being restored to values much bigger than the proper values.
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Fixes: e33099f9 ("tcp: implement RFC5682 F-RTO")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_tw_recycle heavily relies on tcp timestamps to build a per-host
ordering of incoming connections and teardowns without the need to
hold state on a specific quadruple for TCP_TIMEWAIT_LEN, but only for
the last measured RTO. To do so, we keep the last seen timestamp in a
per-host indexed data structure and verify if the incoming timestamp
in a connection request is strictly greater than the saved one during
last connection teardown. Thus we can verify later on that no old data
packets will be accepted by the new connection.

During moving a socket to time-wait state we already verify if timestamps
where seen on a connection. Only if that was the case we let the
time-wait socket expire after the RTO, otherwise normal TCP_TIMEWAIT_LEN
will be used. But we don't verify this on incoming SYN packets. If a
connection teardown was less than TCP_PAWS_MSL seconds in the past we
cannot guarantee to not accept data packets from an old connection if
no timestamps are present. We should drop this SYN packet. This patch
closes this loophole.

Please note, this patch does not make tcp_tw_recycle in any way more
usable but only adds another safety check:
Sporadic drops of SYN packets because of reordering in the network or
in the socket backlog queues can happen. Users behing NAT trying to
connect to a tcp_tw_recycle enabled server can get caught in blackholes
and their connection requests may regullary get dropped because hosts
behind an address translator don't have synchronized tcp timestamp clocks.
tcp_tw_recycle cannot work if peers don't have tcp timestamps enabled.

In general, use of tcp_tw_recycle is disadvised.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make sure we use the correct address-family-specific function for
handling MTU reductions from within tcp_release_cb().

Previously AF_INET6 sockets were incorrectly always using the IPv6
code path when sometimes they were handling IPv4 traffic and thus had
an IPv4 dst.
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Diagnosed-by: NWillem de Bruijn <willemb@google.com>
Fixes: 563d34d0 ("tcp: dont drop MTU reduction indications")
Reviewed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As of 4fddbf5d ("sit: strictly restrict incoming traffic to tunnel link device"),
when looking up a tunnel, tunnel's underlying interface (t->parms.link)
is verified to match incoming traffic's ingress device.

However the comparison was incorrectly based on skb->dev->iflink.

Instead, dev->ifindex should be used, which correctly represents the
interface from which the IP stack hands the ipip6 packets.

This allows setting up sit tunnels bound to vlan interfaces (otherwise
incoming ipip6 traffic on the vlan interface was dropped due to
ipip6_tunnel_lookup match failure).
Signed-off-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We don't know right timestamp for repaired skb-s. Wrong RTT estimations
isn't good, because some congestion modules heavily depends on it.

This patch adds the TCPCB_REPAIRED flag, which is included in
TCPCB_RETRANS.

Thanks to Eric for the advice how to fix this issue.

This patch fixes the warning:
[  879.562947] WARNING: CPU: 0 PID: 2825 at net/ipv4/tcp_input.c:3078 tcp_ack+0x11f5/0x1380()
[  879.567253] CPU: 0 PID: 2825 Comm: socket-tcpbuf-l Not tainted 3.16.0-next-20140811 #1
[  879.567829] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  879.568177]  0000000000000000 00000000c532680c ffff880039643d00 ffffffff817aa2d2
[  879.568776]  0000000000000000 ffff880039643d38 ffffffff8109afbd ffff880039d6ba80
[  879.569386]  ffff88003a449800 000000002983d6bd 0000000000000000 000000002983d6bc
[  879.569982] Call Trace:
[  879.570264]  [<ffffffff817aa2d2>] dump_stack+0x4d/0x66
[  879.570599]  [<ffffffff8109afbd>] warn_slowpath_common+0x7d/0xa0
[  879.570935]  [<ffffffff8109b0ea>] warn_slowpath_null+0x1a/0x20
[  879.571292]  [<ffffffff816d0a05>] tcp_ack+0x11f5/0x1380
[  879.571614]  [<ffffffff816d10bd>] tcp_rcv_established+0x1ed/0x710
[  879.571958]  [<ffffffff816dc9da>] tcp_v4_do_rcv+0x10a/0x370
[  879.572315]  [<ffffffff81657459>] release_sock+0x89/0x1d0
[  879.572642]  [<ffffffff816c81a0>] do_tcp_setsockopt.isra.36+0x120/0x860
[  879.573000]  [<ffffffff8110a52e>] ? rcu_read_lock_held+0x6e/0x80
[  879.573352]  [<ffffffff816c8912>] tcp_setsockopt+0x32/0x40
[  879.573678]  [<ffffffff81654ac4>] sock_common_setsockopt+0x14/0x20
[  879.574031]  [<ffffffff816537b0>] SyS_setsockopt+0x80/0xf0
[  879.574393]  [<ffffffff817b40a9>] system_call_fastpath+0x16/0x1b
[  879.574730] ---[ end trace a17cbc38eb8c5c00 ]---

v2: moving setting of skb->when for repaired skb-s in tcp_write_xmit,
    where it's set for other skb-s.

Fixes: 431a9124 ("tcp: timestamp SYN+DATA messages")
Fixes: 740b0f18 ("tcp: switch rtt estimations to usec resolution")
Cc: Eric Dumazet <edumazet@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrey Vagin <avagin@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bytestream timestamps are correlated with a single byte in the skbuff,
recorded in skb_shinfo(skb)->tskey. When fragmenting skbuffs, ensure
that the tskey is set for the fragment in which the tskey falls
(seqno <= tskey < end_seqno).

The original implementation did not address fragmentation in
tcp_fragment or tso_fragment. Add code to inspect the sequence numbers
and move both tskey and the relevant tx_flags if necessary.
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ACK timestamps are generated in tcp_clean_rtx_queue. The TSO datapath
can break out early, causing the timestamp code to be skipped. Move
the code up before the break.
Reported-by: NDavid S. Miller <davem@davemloft.net>

Also fix a boundary condition: tp->snd_una is the next unacknowledged
byte and between tests inclusive (a <= b <= c), so generate a an ACK
timestamp if (prior_snd_una <= tskey <= tp->snd_una - 1).
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NMaks Naumov <maksqwe1@ukr.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

b67bfe0d (hlist: drop the node
parameter from iterators) dropped the node parameter from
iterators which lec_tbl_walk() was using to iterate the list.
Signed-off-by: NChas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

One should not call blocking primitives inside a wait loop, since both
require task_struct::state to sleep, so the inner will destroy the
outer state.

sigd_enq() will possibly sleep for alloc_skb().  Move sigd_enq() before
prepare_to_wait() to avoid sleeping while waiting interruptibly.  You do
not actually need to call sigd_enq() after the initial prepare_to_wait()
because we test the termination condition before calling schedule().

Based on suggestions from Peter Zijlstra.
Signed-off-by: NChas Williams <chas@cmf.n4rl.navy.mil>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>