This patch generates data delivery rate (throughput) samples on a
per-ACK basis. These rate samples can be used by congestion control
modules, and specifically will be used by TCP BBR in later patches in
this series.
Key state:
tp->delivered: Tracks the total number of data packets (original or not)
delivered so far. This is an already-existing field.
tp->delivered_mstamp: the last time tp->delivered was updated.
Algorithm:
A rate sample is calculated as (d1 - d0)/(t1 - t0) on a per-ACK basis:
d1: the current tp->delivered after processing the ACK
t1: the current time after processing the ACK
d0: the prior tp->delivered when the acked skb was transmitted
t0: the prior tp->delivered_mstamp when the acked skb was transmitted
When an skb is transmitted, we snapshot d0 and t0 in its control
block in tcp_rate_skb_sent().
When an ACK arrives, it may SACK and ACK some skbs. For each SACKed
or ACKed skb, tcp_rate_skb_delivered() updates the rate_sample struct
to reflect the latest (d0, t0).
Finally, tcp_rate_gen() generates a rate sample by storing
(d1 - d0) in rs->delivered and (t1 - t0) in rs->interval_us.
One caveat: if an skb was sent with no packets in flight, then
tp->delivered_mstamp may be either invalid (if the connection is
starting) or outdated (if the connection was idle). In that case,
we'll re-stamp tp->delivered_mstamp.
At first glance it seems t0 should always be the time when an skb was
transmitted, but actually this could over-estimate the rate due to
phase mismatch between transmit and ACK events. To track the delivery
rate, we ensure that if packets are in flight then t0 and and t1 are
times at which packets were marked delivered.
If the initial and final RTTs are different then one may be corrupted
by some sort of noise. The noise we see most often is sending gaps
caused by delayed, compressed, or stretched acks. This either affects
both RTTs equally or artificially reduces the final RTT. We approach
this by recording the info we need to compute the initial RTT
(duration of the "send phase" of the window) when we recorded the
associated inflight. Then, for a filter to avoid bandwidth
overestimates, we generalize the per-sample bandwidth computation
from:
bw = delivered / ack_phase_rtt
to the following:
bw = delivered / max(send_phase_rtt, ack_phase_rtt)
In large-scale experiments, this filtering approach incorporating
send_phase_rtt is effective at avoiding bandwidth overestimates due to
ACK compression or stretched ACKs.
Signed-off-by: Van Jacobson <vanj@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Refactor the TCP min_rtt code to reuse the new win_minmax library in
lib/win_minmax.c to simplify the TCP code.
This is a pure refactor: the functionality is exactly the same. We
just moved the windowed min code to make TCP easier to read and
maintain, and to allow other parts of the kernel to use the windowed
min/max filter code.
Signed-off-by: Van Jacobson <vanj@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Johan Hedberg says:
====================
pull request: bluetooth-next 2016-09-19
Here's the main bluetooth-next pull request for the 4.9 kernel.
- Added new messages for monitor sockets for better mgmt tracing
- Added local name and appearance support in scan response
- Added new Qualcomm WCNSS SMD based HCI driver
- Minor fixes & cleanup to 802.15.4 code
- New USB ID to btusb driver
- Added Marvell support to HCI UART driver
- Add combined LED trigger for controller power
- Other minor fixes here and there
Please let me know if there are any issues pulling. Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch enables prepending appearance value to scan response data.
It also adds support for setting appearance value through mgmt command.
If currently advertised instance has apperance flag set it is expired
immediately.
Signed-off-by: Michał Narajowski <michal.narajowski@codecoup.pl>
Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
While the subsystem version information are purely informational,
increase the minor number due to the addition of user channel and
management control monitoring suppport. It is helpful for debugging
purposes to see the version numbers change.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This command is used to retrieve the current state and basic
information of a controller. It is typically used right after
getting the response to the Read Controller Index List command
or an Index Added event (or its extended counterparts).
When any of the values in the EIR_Data field changes, the event
Extended Controller Information Changed will be used to inform
clients about the updated information.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Michał Narajowski <michal.narajowski@codecoup.pl>
Instead of keeping a version string around, use version and revision
numbers and then stringify them for use as module parameter.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Instead of hiding everything behind a general managment events flag,
introduce indivdual flags that allow fine control over which events are
send to a given management channel.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This adds support for tracing all management commands and events via the
monitor interface.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This sends new notifications to the monitor support whenever a
management channel has been opened or closed. This allows tracing of
control channels really easily.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The mgmt version information will be also needed for the control
changell tracing feature. This provides a helper to pack them.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
To further allow unique identification and tracking of control socket,
store cookie and comm information when binding the socket.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Commit 5177a83827 ("Bluetooth: Add debugfs fields for hardware and
firmware info") introduced hci_set_hw_info() and hci_set_fw_info().
These functions use kvasprintf_const() but are not marked with a
__printf attribute. Adding such an attribute helps detecting issues
related to printf-formatting at build time.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This patch assigns the next free HCI device identifier to Bluetooth
devices based on the Qualcomm Shared Memory channels.
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The led_trigger field in hci_dev should be conditional based on if
CONFIG_BT_LEDS is set or not.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This change replaces sk_buff_head struct in Qdiscs with new qdisc_skb_head.
Its similar to the skb_buff_head api, but does not use skb->prev pointers.
Qdiscs will commonly enqueue at the tail of a list and dequeue at head.
While skb_buff_head works fine for this, enqueue/dequeue needs to also
adjust the prev pointer of next element.
The ->prev pointer is not required for qdiscs so we can just leave
it undefined and avoid one cacheline write access for en/dequeue.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Moves qdisc stat accouting to qdisc_dequeue_head.
The only direct caller of the __qdisc_dequeue_head version open-codes
this now.
This allows us to later use __qdisc_dequeue_head as a replacement
of __skb_dequeue() (which operates on sk_buff_head list).
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make ip6_route_input_lookup available outside of ipv6 the module
similar to ip_route_input_noref in the IPv4 world.
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* MU-MIMO sniffer support in mac80211
* a create_singlethread_workqueue() cleanup
* interface dump filtering that was documented but not implemented
* support for the new radiotap timestamp field
* send delBA in two unexpected conditions (as required by the spec)
* connect keys cleanups - allow only WEP with index 0-3
* per-station aggregation limit to work around broken APs
* debugfs improvement for the integrated codel algorithm
and various other small improvements and cleanups.
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Merge tag 'mac80211-next-for-davem-2016-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next
Johannes Berg says:
====================
This time we have various things - all across the board:
* MU-MIMO sniffer support in mac80211
* a create_singlethread_workqueue() cleanup
* interface dump filtering that was documented but not implemented
* support for the new radiotap timestamp field
* send delBA in two unexpected conditions (as required by the spec)
* connect keys cleanups - allow only WEP with index 0-3
* per-station aggregation limit to work around broken APs
* debugfs improvement for the integrated codel algorithm
and various other small improvements and cleanups.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_outq_flush return value is meaningless now, this patch is
to make sctp_outq_flush return void, as well as sctp_outq_fail
and sctp_outq_uncork.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Last patch "sctp: do not return the transmit err back to sctp_sendmsg"
made sctp_primitive_SEND return err only when asoc state is unavailable.
In this case, chunks are not enqueued, they have no chance to be freed if
we don't take care of them later.
This Patch is actually to revert commit 1cd4d5c432 ("sctp: remove the
unused sctp_datamsg_free()"), commit 69b5777f2e ("sctp: hold the chunks
only after the chunk is enqueued in outq") and commit 8b570dc9f7 ("sctp:
only drop the reference on the datamsg after sending a msg"), to use
sctp_datamsg_free to free the chunks of current msg.
Fixes: 8b570dc9f7 ("sctp: only drop the reference on the datamsg after sending a msg")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to gre, vxlan, geneve tunnels allow IPIP6 and IP6IP6 tunnels
to operate in 'collect metadata' mode.
Unlike ipv4 code here it's possible to reuse ip6_tnl_xmit() function
for both collect_md and traditional tunnels.
bpf_skb_[gs]et_tunnel_key() helpers and ovs (in the future) are the users.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to gre, vxlan, geneve tunnels allow IPIP tunnels to
operate in 'collect metadata' mode.
bpf_skb_[gs]et_tunnel_key() helpers can make use of it right away.
ovs can use it as well in the future (once appropriate ovs-vport
abstractions and user apis are added).
Note that just like in other tunnels we cannot cache the dst,
since tunnel_info metadata can be different for every packet.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
No longer used after e0d56fdd73 ("net: l3mdev: remove redundant calls")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are a few places where an IE that matches not only the EID, but
also other bytes inside the element, needs to be found. To simplify
that and reduce the amount of similar code, implement a new helper
function to match the EID and an extra array of bytes.
Additionally, simplify cfg80211_find_vendor_ie() by using the new
match function.
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Add support for the 2-bytes Qualcomm tag that gigabit switches such as
the QCA8337/N might insert when receiving packets, or that we need
to insert while targeting specific switch ports. The tag is inserted
directly behind the ethernet header.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This action is intended to be an upgrade from a usability perspective
from pedit (as well as operational debugability).
Compare this:
sudo tc filter add dev $ETH parent 1: protocol ip prio 10 \
u32 match ip protocol 1 0xff flowid 1:2 \
action pedit munge offset -14 u8 set 0x02 \
munge offset -13 u8 set 0x15 \
munge offset -12 u8 set 0x15 \
munge offset -11 u8 set 0x15 \
munge offset -10 u16 set 0x1515 \
pipe
to:
sudo tc filter add dev $ETH parent 1: protocol ip prio 10 \
u32 match ip protocol 1 0xff flowid 1:2 \
action skbmod dmac 02:15:15:15:15:15
Also try to do a MAC address swap with pedit or worse
try to debug a policy with destination mac, source mac and
etherype. Then make few rules out of those and you'll get my point.
In the future common use cases on pedit can be migrated to this action
(as an example different fields in ip v4/6, transports like tcp/udp/sctp
etc). For this first cut, this allows modifying basic ethernet header.
The most important ethernet use case at the moment is when redirecting or
mirroring packets to a remote machine. The dst mac address needs a re-write
so that it doesnt get dropped or confuse an interconnecting (learning) switch
or dropped by a target machine (which looks at the dst mac). And at times
when flipping back the packet a swap of the MAC addresses is needed.
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based on consecutive msdu failures, mac80211 triggers CQM packet-loss
mechanism. Drivers like ath10k that have its own connection monitoring
algorithm, offloaded to firmware for triggering station kickout. In case
of station kickout, driver will report low ack status by mac80211 API
(ieee80211_report_low_ack).
This flag will enable the driver to completely rely on firmware events
for station kickout and bypass mac80211 packet loss mechanism.
Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
No drivers implement this, relying either on the recursive
directory removal to remove their debugfs, or not having any
to start with. Remove the dead driver callback.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Conflicts:
drivers/net/ethernet/mediatek/mtk_eth_soc.c
drivers/net/ethernet/qlogic/qed/qed_dcbx.c
drivers/net/phy/Kconfig
All conflicts were cases of overlapping commits.
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the existing device timestamp from the RX status information
to add support for the new radiotap timestamp field. Currently
only 32-bit counters are supported, but we also add the radiotap
mactime where applicable. This new field allows more flexibility
in where the timestamp is taken etc. The non-timestamp data in
the field is taken from a new field in the hw struct.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The ability to change the max_rx_aggregation frames is useful
in cases of IOP.
There exist some devices (latest mobile phones and some AP's)
that tend to not respect a BA sessions maximum size (in Kbps).
These devices won't respect the AMPDU size that was negotiated during
association (even though they do respect the maximal number of packets).
This violation is characterized by a valid number of packets in
a single AMPDU. Even so, the total size will exceed the size negotiated
during association.
Eventually, this will cause some undefined behavior, which in turn
causes the hw to drop packets, causing the throughput to plummet.
This patch will make the subframe limitation to be held by each station,
instead of being held only by hw.
Signed-off-by: Maxim Altshul <maxim.altshul@ti.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
cfg80211 expects the .disconnect() handler to call
cfg80211_disconnect() when done. Make this requirement
more explicit.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Flip the IPv6 output path to use the l3mdev tx out hook. The VRF dst
is not returned on the first FIB lookup. Instead, the dst on the
skb is switched at the beginning of the IPv6 output processing to
send the packet to the VRF driver on xmit.
Link scope addresses (linklocal and multicast) need special handling:
specifically the oif the flow struct can not be changed because we
want the lookup tied to the enslaved interface. ie., the source address
and the returned route MUST point to the interface scope passed in.
Convert the existing vrf_get_rt6_dst to handle only link scope addresses.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow an L3 master device to act as the loopback for that L3 domain.
For IPv4 the device can also have the address 127.0.0.1.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the infrastructure to the output path to pass an skb
to an l3mdev device if it has a hook registered. This is the Tx parallel
to l3mdev_ip{6}_rcv in the receive path and is the basis for removing
the existing hook that returns the vrf dst on the fib lookup.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add l3mdev hook to set FLOWI_FLAG_SKIP_NH_OIF flag and update oif/iif
in flow struct if its oif or iif points to a device enslaved to an L3
Master device. Only 1 needs to be converted to match the l3mdev FIB
rule. This moves the flow adjustment for l3mdev to a single point
catching all lookups. It is redundant for existing hooks (those are
removed in later patches) but is needed for missed lookups such as
PMTU updates.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This action could be used before redirecting packets to a shared tunnel
device, or when redirecting packets arriving from a such a device.
The action will release the metadata created by the tunnel device
(decap), or set the metadata with the specified values for encap
operation.
For example, the following flower filter will forward all ICMP packets
destined to 11.11.11.2 through the shared vxlan device 'vxlan0'. Before
redirecting, a metadata for the vxlan tunnel is created using the
tunnel_key action and it's arguments:
$ tc filter add dev net0 protocol ip parent ffff: \
flower \
ip_proto 1 \
dst_ip 11.11.11.2 \
action tunnel_key set \
src_ip 11.11.0.1 \
dst_ip 11.11.0.2 \
id 11 \
action mirred egress redirect dev vxlan0
Signed-off-by: Amir Vadai <amir@vadai.me>
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Extract __ip_tun_set_dst() and __ipv6_tun_set_dst() out of
ip_tun_rx_dst() and ipv6_tun_rx_dst(), to be used without supplying an
skb.
Signed-off-by: Amir Vadai <amir@vadai.me>
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add utility functions to convert a 32 bits key into a 64 bits tunnel and
vice versa.
These functions will be used instead of cloning code in GRE and VXLAN,
and in tc act_iptunnel which will be introduced in a following patch in
this patchset.
Signed-off-by: Amir Vadai <amir@vadai.me>
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Merge tag 'rxrpc-rewrite-20160908' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
David Howells says:
====================
rxrpc: Rewrite data and ack handling
This patch set constitutes the main portion of the AF_RXRPC rewrite. It
consists of five fix/helper patches:
(1) Fix ASSERTCMP's and ASSERTIFCMP's handling of signed values.
(2) Update some protocol definitions slightly.
(3) Use of an hlist for RCU purposes.
(4) Removal of per-call sk_buff accounting (not really needed when skbs
aren't being queued on the main queue).
(5) Addition of a tracepoint to log incoming packets in the data_ready
callback and to log the end of the data_ready callback.
And then there are two patches that form the main part:
(6) Preallocation of resources for incoming calls so that in patch (7) the
data_ready handler can be made to fully instantiate an incoming call
and make it live. This extends through into AFS so that AFS can
preallocate its own incoming call resources.
The preallocation size is capped at the listen() backlog setting - and
that is capped at a sysctl limit which can be set between 4 and 32.
The preallocation is (re)charged either by accepting/rejecting pending
calls or, in the case of AFS, manually. If insufficient preallocation
resources exist, a BUSY packet will be transmitted.
The advantage of using this preallocation is that once a call is set
up in the data_ready handler, DATA packets can be queued on it
immediately rather than the DATA packets being queued for a background
work item to do all the allocation and then try and sort out the DATA
packets whilst other DATA packets may still be coming in and going
either to the background thread or the new call.
(7) Rewrite the handling of DATA, ACK and ABORT packets.
In the receive phase, DATA packets are now held in per-call circular
buffers with deduplication, out of sequence detection and suchlike
being done in data_ready. Since there is only one producer and only
once consumer, no locks need be used on the receive queue.
Received ACK and ABORT packets are now parsed and discarded in
data_ready to recycle resources as fast as possible.
sk_buffs are no longer pulled, trimmed or cloned, but rather the
offset and size of the content is tracked. This particularly affects
jumbo DATA packets which need insertion into the receive buffer in
multiple places. Annotations are kept to track which bit is which.
Packets are no longer queued on the socket receive queue; rather,
calls are queued. Dummy packets to convey events therefore no longer
need to be invented and metadata packets can be discarded as soon as
parsed rather then being pushed onto the socket receive queue to
indicate terminal events.
The preallocation facility added in (6) is now used to set up incoming
calls with very little locking required and no calls to the allocator
in data_ready.
Decryption and verification is now handled in recvmsg() rather than in
a background thread. This allows for the future possibility of
decrypting directly into the user buffer.
With this patch, the code is a lot simpler and most of the mass of
call event and state wangling code in call_event.c is gone.
With this, the majority of the AF_RXRPC rewrite is complete. However,
there are still things to be done, including:
(*) Limit the number of active service calls to prevent an attacker from
filling up a server's memory.
(*) Limit the number of calls on the rebuff-with-BUSY queue.
(*) Transmit delayed/deferred ACKs from recvmsg() if possible, rather than
punting to the background thread. Ideally, the background thread
shouldn't run at all, but data_ready can't call kernel_sendmsg() and
we can't rely on recvmsg() attending to the call in a timely fashion.
(*) Prevent the call at the front of the socket queue from hogging
recvmsg()'s attention if there's a sufficiently continuous supply of
data.
(*) Distribute ICMP errors by connection rather than by call. Possibly
parse the ICMP packet to try and pin down the exact connection and
call.
(*) Encrypt/decrypt directly between user buffers and socket buffers where
possible.
(*) IPv6.
(*) Service ID upgrade. This is a facility whereby a special flag bit is
set in the DATA packet header when making a call that tells the server
that it is allowed to change the service ID to an upgraded one and
reply with an equivalent call from the upgraded service.
This is used, for example, to override certain AFS calls so that IPv6
addresses can be returned.
(*) Allow userspace to preallocate call user IDs for incoming calls.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Over the years, TCP BDP has increased by several orders of magnitude,
and some people are considering to reach the 2 Gbytes limit.
Even with current window scale limit of 14, ~1 Gbytes maps to ~740,000
MSS.
In presence of packet losses (or reorders), TCP stores incoming packets
into an out of order queue, and number of skbs sitting there waiting for
the missing packets to be received can be in the 10^5 range.
Most packets are appended to the tail of this queue, and when
packets can finally be transferred to receive queue, we scan the queue
from its head.
However, in presence of heavy losses, we might have to find an arbitrary
point in this queue, involving a linear scan for every incoming packet,
throwing away cpu caches.
This patch converts it to a RB tree, to get bounded latencies.
Yaogong wrote a preliminary patch about 2 years ago.
Eric did the rebase, added ofo_last_skb cache, polishing and tests.
Tested with network dropping between 1 and 10 % packets, with good
success (about 30 % increase of throughput in stress tests)
Next step would be to also use an RB tree for the write queue at sender
side ;)
Signed-off-by: Yaogong Wang <wygivan@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-By: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Steffen Klassert says:
====================
ipsec-next 2016-09-08
1) Constify the xfrm_replay structures. From Julia Lawall
2) Protect xfrm state hash tables with rcu, lookups
can be done now without acquiring xfrm_state_lock.
From Florian Westphal.
3) Protect xfrm policy hash tables with rcu, lookups
can be done now without acquiring xfrm_policy_lock.
From Florian Westphal.
4) We don't need to have a garbage collector list per
namespace anymore, so use a global one instead.
From Florian Westphal.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Rewrite the data and ack handling code such that:
(1) Parsing of received ACK and ABORT packets and the distribution and the
filing of DATA packets happens entirely within the data_ready context
called from the UDP socket. This allows us to process and discard ACK
and ABORT packets much more quickly (they're no longer stashed on a
queue for a background thread to process).
(2) We avoid calling skb_clone(), pskb_pull() and pskb_trim(). We instead
keep track of the offset and length of the content of each packet in
the sk_buff metadata. This means we don't do any allocation in the
receive path.
(3) Jumbo DATA packet parsing is now done in data_ready context. Rather
than cloning the packet once for each subpacket and pulling/trimming
it, we file the packet multiple times with an annotation for each
indicating which subpacket is there. From that we can directly
calculate the offset and length.
(4) A call's receive queue can be accessed without taking locks (memory
barriers do have to be used, though).
(5) Incoming calls are set up from preallocated resources and immediately
made live. They can than have packets queued upon them and ACKs
generated. If insufficient resources exist, DATA packet #1 is given a
BUSY reply and other DATA packets are discarded).
(6) sk_buffs no longer take a ref on their parent call.
To make this work, the following changes are made:
(1) Each call's receive buffer is now a circular buffer of sk_buff
pointers (rxtx_buffer) rather than a number of sk_buff_heads spread
between the call and the socket. This permits each sk_buff to be in
the buffer multiple times. The receive buffer is reused for the
transmit buffer.
(2) A circular buffer of annotations (rxtx_annotations) is kept parallel
to the data buffer. Transmission phase annotations indicate whether a
buffered packet has been ACK'd or not and whether it needs
retransmission.
Receive phase annotations indicate whether a slot holds a whole packet
or a jumbo subpacket and, if the latter, which subpacket. They also
note whether the packet has been decrypted in place.
(3) DATA packet window tracking is much simplified. Each phase has just
two numbers representing the window (rx_hard_ack/rx_top and
tx_hard_ack/tx_top).
The hard_ack number is the sequence number before base of the window,
representing the last packet the other side says it has consumed.
hard_ack starts from 0 and the first packet is sequence number 1.
The top number is the sequence number of the highest-numbered packet
residing in the buffer. Packets between hard_ack+1 and top are
soft-ACK'd to indicate they've been received, but not yet consumed.
Four macros, before(), before_eq(), after() and after_eq() are added
to compare sequence numbers within the window. This allows for the
top of the window to wrap when the hard-ack sequence number gets close
to the limit.
Two flags, RXRPC_CALL_RX_LAST and RXRPC_CALL_TX_LAST, are added also
to indicate when rx_top and tx_top point at the packets with the
LAST_PACKET bit set, indicating the end of the phase.
(4) Calls are queued on the socket 'receive queue' rather than packets.
This means that we don't need have to invent dummy packets to queue to
indicate abnormal/terminal states and we don't have to keep metadata
packets (such as ABORTs) around
(5) The offset and length of a (sub)packet's content are now passed to
the verify_packet security op. This is currently expected to decrypt
the packet in place and validate it.
However, there's now nowhere to store the revised offset and length of
the actual data within the decrypted blob (there may be a header and
padding to skip) because an sk_buff may represent multiple packets, so
a locate_data security op is added to retrieve these details from the
sk_buff content when needed.
(6) recvmsg() now has to handle jumbo subpackets, where each subpacket is
individually secured and needs to be individually decrypted. The code
to do this is broken out into rxrpc_recvmsg_data() and shared with the
kernel API. It now iterates over the call's receive buffer rather
than walking the socket receive queue.
Additional changes:
(1) The timers are condensed to a single timer that is set for the soonest
of three timeouts (delayed ACK generation, DATA retransmission and
call lifespan).
(2) Transmission of ACK and ABORT packets is effected immediately from
process-context socket ops/kernel API calls that cause them instead of
them being punted off to a background work item. The data_ready
handler still has to defer to the background, though.
(3) A shutdown op is added to the AF_RXRPC socket so that the AFS
filesystem can shut down the socket and flush its own work items
before closing the socket to deal with any in-progress service calls.
Future additional changes that will need to be considered:
(1) Make sure that a call doesn't hog the front of the queue by receiving
data from the network as fast as userspace is consuming it to the
exclusion of other calls.
(2) Transmit delayed ACKs from within recvmsg() when we've consumed
sufficiently more packets to avoid the background work item needing to
run.
Signed-off-by: David Howells <dhowells@redhat.com>
