Commit Graph

232 Commits

Author SHA1 Message Date
Thomas Gleixner 457c899653 treewide: Add SPDX license identifier for missed files
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:45 +02:00
Yuchung Cheng 336c39a031 tcp: undo init congestion window on false SYNACK timeout
Linux implements RFC6298 and use an initial congestion window
of 1 upon establishing the connection if the SYNACK packet is
retransmitted 2 or more times. In cellular networks SYNACK timeouts
are often spurious if the wireless radio was dormant or idle. Also
some network path is longer than the default SYNACK timeout. In
both cases falsely starting with a minimal cwnd are detrimental
to performance.

This patch avoids doing so when the final ACK's TCP timestamp
indicates the original SYNACK was delivered. It remembers the
original SYNACK timestamp when SYNACK timeout has occurred and
re-uses the function to detect spurious SYN timeout conveniently.

Note that a server may receives multiple SYNs from and immediately
retransmits SYNACKs without any SYNACK timeout. This often happens
on when the client SYNs have timed out due to wireless delay
above. In this case since the server will still use the default
initial congestion (e.g. 10) because tp->undo_marker is reset in
tcp_init_metrics(). This is an intentional design because packets
are not lost but delayed.

This patch only covers regular TCP passive open. Fast Open is
supported in the next patch.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-01 11:47:54 -04:00
Eric Dumazet 6aedbf986f tcp: use tcp_md5_needed for timewait sockets
This might speedup tcp_twsk_destructor() a bit,
avoiding a cache line miss.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-26 13:16:03 -08:00
Eric Dumazet 6bcdc40ddd tcp: move rx_opt & syn_data_acked init to tcp_disconnect()
If we make sure all listeners have these fields cleared, then a clone
will also inherit zero values.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet 792c4354a5 tcp: move tp->rack init to tcp_disconnect()
If we make sure all listeners have proper tp->rack value,
then a clone will also inherit proper initial value.

Note that fresh sockets init tp->rack from tcp_init_sock()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet 6cda8b7493 tcp: move app_limited init to tcp_disconnect()
If we make sure all listeners have app_limited set to ~0U,
then a clone will also inherit proper initial value.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet 5c701549c9 tcp: move retrans_out, sacked_out, tlp_high_seq, last_oow_ack_time init to tcp_disconnect()
If we make sure all listeners have these fields cleared, then a clone
will also inherit zero values.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet 5d83676462 tcp: do not clear urg_data in tcp_create_openreq_child
All listeners have this field cleared already, since tcp_disconnect()
clears it and newly created sockets have also a zero value here.

So a clone will inherit a zero value here.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet 3a9a57f637 tcp: move snd_cwnd & snd_cwnd_cnt init to tcp_disconnect()
Passive connections can inherit proper value by cloning,
if we make sure all listeners have the proper values there.

tcp_disconnect() was setting snd_cwnd to 2, which seems
quite obsolete since IW10 adoption.

Also remove an obsolete comment.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet b9e2e689aa tcp: move mdev_us init to tcp_disconnect()
If we make sure a listener always has its mdev_us
field set to TCP_TIMEOUT_INIT, we do not need to rewrite
this field after a new clone is created.

tcp_disconnect() is very seldom used in real applications.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet a0070e463f tcp: do not clear srtt_us in tcp_create_openreq_child
All listeners have this field cleared already, since tcp_disconnect()
clears it and newly created sockets have also a zero value here.

So a clone will inherit a zero value here.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:05 -08:00
Eric Dumazet eb2c80ca87 tcp: do not clear packets_out in tcp_create_openreq_child()
New sockets have this field cleared, and tcp_disconnect()
calls tcp_write_queue_purge() which among other things
also clear tp->packets_out

So a listener is guaranteed to have this field cleared.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:04 -08:00
Eric Dumazet 6a408147ea tcp: move icsk_rto init to tcp_disconnect()
If we make sure a listener always has its icsk_rto
field set to TCP_TIMEOUT_INIT, we do not need to rewrite
this field after a new clone is created.

tcp_disconnect() is very seldom used in real applications.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:04 -08:00
Eric Dumazet b84235e291 tcp: do not set snd_ssthresh in tcp_create_openreq_child()
New sockets get the field set to TCP_INFINITE_SSTHRESH in tcp_init_sock()
In case a socket had this field changed and transitions to TCP_LISTEN
state, tcp_disconnect() also makes sure snd_ssthresh is set to
TCP_INFINITE_SSTHRESH.

So a listener has this field set to TCP_INFINITE_SSTHRESH already.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17 22:19:04 -08:00
Florian Westphal 63cc357f7b tcp: do not restart timewait timer on rst reception
RFC 1337 says:
 ''Ignore RST segments in TIME-WAIT state.
   If the 2 minute MSL is enforced, this fix avoids all three hazards.''

So with net.ipv4.tcp_rfc1337=1, expected behaviour is to have TIME-WAIT sk
expire rather than removing it instantly when a reset is received.

However, Linux will also re-start the TIME-WAIT timer.

This causes connect to fail when tying to re-use ports or very long
delays (until syn retry interval exceeds MSL).

packetdrill test case:
// Demonstrate bogus rearming of TIME-WAIT timer in rfc1337 mode.
`sysctl net.ipv4.tcp_rfc1337=1`

0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
0.000 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
0.000 bind(3, ..., ...) = 0
0.000 listen(3, 1) = 0

0.100 < S 0:0(0) win 29200 <mss 1460,nop,nop,sackOK,nop,wscale 7>
0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7>
0.200 < . 1:1(0) ack 1 win 257
0.200 accept(3, ..., ...) = 4

// Receive first segment
0.310 < P. 1:1001(1000) ack 1 win 46

// Send one ACK
0.310 > . 1:1(0) ack 1001

// read 1000 byte
0.310 read(4, ..., 1000) = 1000

// Application writes 100 bytes
0.350 write(4, ..., 100) = 100
0.350 > P. 1:101(100) ack 1001

// ACK
0.500 < . 1001:1001(0) ack 101 win 257

// close the connection
0.600 close(4) = 0
0.600 > F. 101:101(0) ack 1001 win 244

// Our side is in FIN_WAIT_1 & waits for ack to fin
0.7 < . 1001:1001(0) ack 102 win 244

// Our side is in FIN_WAIT_2 with no outstanding data.
0.8 < F. 1001:1001(0) ack 102 win 244
0.8 > . 102:102(0) ack 1002 win 244

// Our side is now in TIME_WAIT state, send ack for fin.
0.9 < F. 1002:1002(0) ack 102 win 244
0.9 > . 102:102(0) ack 1002 win 244

// Peer reopens with in-window SYN:
1.000 < S 1000:1000(0) win 9200 <mss 1460,nop,nop,sackOK,nop,wscale 7>

// Therefore, reply with ACK.
1.000 > . 102:102(0) ack 1002 win 244

// Peer sends RST for this ACK.  Normally this RST results
// in tw socket removal, but rfc1337=1 setting prevents this.
1.100 < R 1002:1002(0) win 244

// second syn. Due to rfc1337=1 expect another pure ACK.
31.0 < S 1000:1000(0) win 9200 <mss 1460,nop,nop,sackOK,nop,wscale 7>
31.0 > . 102:102(0) ack 1002 win 244

// .. and another RST from peer.
31.1 < R 1002:1002(0) win 244
31.2 `echo no timer restart;ss -m -e -a -i -n -t -o state TIME-WAIT`

// third syn after one minute.  Time-Wait socket should have expired by now.
63.0 < S 1000:1000(0) win 9200 <mss 1460,nop,nop,sackOK,nop,wscale 7>

// so we expect a syn-ack & 3whs to proceed from here on.
63.0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7>

Without this patch, 'ss' shows restarts of tw timer and last packet is
thus just another pure ack, more than one minute later.

This restores the original code from commit 283fd6cf0be690a83
("Merge in ANK networking jumbo patch") in netdev-vger-cvs.git .

For some reason the else branch was removed/lost in 1f28b683339f7
("Merge in TCP/UDP optimizations and [..]") and timer restart became
unconditional.

Reported-by: Michal Tesar <mtesar@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-31 23:10:35 -07:00
Arnd Bergmann cca9bab1b7 tcp: use monotonic timestamps for PAWS
Using get_seconds() for timestamps is deprecated since it can lead
to overflows on 32-bit systems. While the interface generally doesn't
overflow until year 2106, the specific implementation of the TCP PAWS
algorithm breaks in 2038 when the intermediate signed 32-bit timestamps
overflow.

A related problem is that the local timestamps in CLOCK_REALTIME form
lead to unexpected behavior when settimeofday is called to set the system
clock backwards or forwards by more than 24 days.

While the first problem could be solved by using an overflow-safe method
of comparing the timestamps, a nicer solution is to use a monotonic
clocksource with ktime_get_seconds() that simply doesn't overflow (at
least not until 136 years after boot) and that doesn't change during
settimeofday().

To make 32-bit and 64-bit architectures behave the same way here, and
also save a few bytes in the tcp_options_received structure, I'm changing
the type to a 32-bit integer, which is now safe on all architectures.

Finally, the ts_recent_stamp field also (confusingly) gets used to store
a jiffies value in tcp_synq_overflow()/tcp_synq_no_recent_overflow().
This is currently safe, but changing the type to 32-bit requires
some small changes there to keep it working.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 14:50:40 -07:00
Eric Dumazet 242b1bbe51 tcp: remove one indentation level in tcp_create_openreq_child
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-28 16:02:31 +09:00
Maciej Żenczykowski 95358a9553 net-tcp: remove useless tw_timeout field
Tested: 'git grep tw_timeout' comes up empty and it builds :-)

Signed-off-by: Maciej Żenczykowski <maze@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-05 10:45:24 -04:00
Jon Maxwell 0048369055 tcp: Add mark for TIMEWAIT sockets
This version has some suggestions by Eric Dumazet:

- Use a local variable for the mark in IPv6 instead of ctl_sk to avoid SMP
races.
- Use the more elegant "IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark"
statement.
- Factorize code as sk_fullsock() check is not necessary.

Aidan McGurn from Openwave Mobility systems reported the following bug:

"Marked routing is broken on customer deployment. Its effects are large
increase in Uplink retransmissions caused by the client never receiving
the final ACK to their FINACK - this ACK misses the mark and routes out
of the incorrect route."

Currently marks are added to sk_buffs for replies when the "fwmark_reflect"
sysctl is enabled. But not for TW sockets that had sk->sk_mark set via
setsockopt(SO_MARK..).

Fix this in IPv4/v6 by adding tw->tw_mark for TIME_WAIT sockets. Copy the the
original sk->sk_mark in __inet_twsk_hashdance() to the new tw->tw_mark location.
Then progate this so that the skb gets sent with the correct mark. Do the same
for resets. Give the "fwmark_reflect" sysctl precedence over sk->sk_mark so that
netfilter rules are still honored.

Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-10 17:44:52 -04:00
Atul Gupta cc35c88ae4 crypto : chtls - CPL handler definition
Exchange messages with hardware to program the TLS session
CPL handlers for messages received from chip.

Signed-off-by: Atul Gupta <atul.gupta@chelsio.com>
Signed-off-by: Michael Werner <werner@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-31 23:37:32 -04:00
Eric Dumazet e0f9759f53 tcp: try to keep packet if SYN_RCV race is lost
배석진 reported that in some situations, packets for a given 5-tuple
end up being processed by different CPUS.

This involves RPS, and fragmentation.

배석진 is seeing packet drops when a SYN_RECV request socket is
moved into ESTABLISH state. Other states are protected by socket lock.

This is caused by a CPU losing the race, and simply not caring enough.

Since this seems to occur frequently, we can do better and perform
a second lookup.

Note that all needed memory barriers are already in the existing code,
thanks to the spin_lock()/spin_unlock() pair in inet_ehash_insert()
and reqsk_put(). The second lookup must find the new socket,
unless it has already been accepted and closed by another cpu.

Note that the fragmentation could be avoided in the first place by
use of a correct TCP MSS option in the SYN{ACK} packet, but this
does not mean we can not be more robust.

Many thanks to 배석진 for a very detailed analysis.

Reported-by: 배석진 <soukjin.bae@samsung.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-14 14:21:45 -05:00
Eric Dumazet ec94c2696f tcp/dccp: avoid one atomic operation for timewait hashdance
First, rename __inet_twsk_hashdance() to inet_twsk_hashdance()

Then, remove one inet_twsk_put() by setting tw_refcnt to 3 instead
of 4, but adding a fat warning that we do not have the right to access
tw anymore after inet_twsk_hashdance()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-13 14:33:10 -05:00
Eric Dumazet cfac7f836a tcp/dccp: block bh before arming time_wait timer
Maciej Żenczykowski reported some panics in tcp_twsk_destructor()
that might be caused by the following bug.

timewait timer is pinned to the cpu, because we want to transition
timwewait refcount from 0 to 4 in one go, once everything has been
initialized.

At the time commit ed2e923945 ("tcp/dccp: fix timewait races in timer
handling") was merged, TCP was always running from BH habdler.

After commit 5413d1babe ("net: do not block BH while processing
socket backlog") we definitely can run tcp_time_wait() from process
context.

We need to block BH in the critical section so that the pinned timer
has still its purpose.

This bug is more likely to happen under stress and when very small RTO
are used in datacenter flows.

Fixes: 5413d1babe ("net: do not block BH while processing socket backlog")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Maciej Żenczykowski <maze@google.com>
Acked-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-01 15:07:43 -05:00
Yuchung Cheng 737ff31456 tcp: use sequence distance to detect reordering
Replace the reordering distance measurement in packet unit with
sequence based approach. Previously it trackes the number of "packets"
toward the forward ACK (i.e.  highest sacked sequence)in a state
variable "fackets_out".

Precisely measuring reordering degree on packet distance has not much
benefit, as the degree constantly changes by factors like path, load,
and congestion window. It is also complicated and prone to arcane bugs.
This patch replaces with sequence-based approach that's much simpler.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11 18:53:16 +09:00
Yuchung Cheng 713bafea92 tcp: retire FACK loss detection
FACK loss detection has been disabled by default and the
successor RACK subsumed FACK and can handle reordering better.
This patch removes FACK to simplify TCP loss recovery.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11 18:53:16 +09:00
Priyaranjan Jha 1f2556916d tcp: higher throughput under reordering with adaptive RACK reordering wnd
Currently TCP RACK loss detection does not work well if packets are
being reordered beyond its static reordering window (min_rtt/4).Under
such reordering it may falsely trigger loss recoveries and reduce TCP
throughput significantly.

This patch improves that by increasing and reducing the reordering
window based on DSACK, which is now supported in major TCP implementations.
It makes RACK's reo_wnd adaptive based on DSACK and no. of recoveries.

- If DSACK is received, increment reo_wnd by min_rtt/4 (upper bounded
  by srtt), since there is possibility that spurious retransmission was
  due to reordering delay longer than reo_wnd.

- Persist the current reo_wnd value for TCP_RACK_RECOVERY_THRESH (16)
  no. of successful recoveries (accounts for full DSACK-based loss
  recovery undo). After that, reset it to default (min_rtt/4).

- At max, reo_wnd is incremented only once per rtt. So that the new
  DSACK on which we are reacting, is due to the spurious retx (approx)
  after the reo_wnd has been updated last time.

- reo_wnd is tracked in terms of steps (of min_rtt/4), rather than
  absolute value to account for change in rtt.

In our internal testing, we observed significant increase in throughput,
in scenarios where reordering exceeds min_rtt/4 (previous static value).

Signed-off-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-05 23:15:42 +09:00
Eric Dumazet ceef9ab6be tcp: Namespace-ify sysctl_tcp_workaround_signed_windows
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet 0bc65a28ae tcp: Namespace-ify sysctl_tcp_fack
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet 65c9410cf5 tcp: Namespace-ify sysctl_tcp_abort_on_overflow
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet 625357aa17 tcp: Namespace-ify sysctl_tcp_rfc1337
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Ursula Braun 60e2a77807 tcp: TCP experimental option for SMC
The SMC protocol [1] relies on the use of a new TCP experimental
option [2, 3]. With this option, SMC capabilities are exchanged
between peers during the TCP three way handshake. This patch adds
support for this experimental option to TCP.

References:
[1] SMC-R Informational RFC: http://www.rfc-editor.org/info/rfc7609
[2] Shared Use of TCP Experimental Options RFC 6994:
    https://tools.ietf.org/rfc/rfc6994.txt
[3] IANA ExID SMCR:
http://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml#tcp-exids

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-26 18:00:29 +09:00
Gustavo A. R. Silva 49ca1943a7 ipv4: tcp_minisocks: use BUG_ON instead of if condition followed by BUG
Use BUG_ON instead of if condition followed by BUG in tcp_time_wait.

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24 18:44:42 +09:00
Eric Dumazet e2080072ed tcp: new list for sent but unacked skbs for RACK recovery
This patch adds a new queue (list) that tracks the sent but not yet
acked or SACKed skbs for a TCP connection. The list is chronologically
ordered by skb->skb_mstamp (the head is the oldest sent skb).

This list will be used to optimize TCP Rack recovery, which checks
an skb's timestamp to judge if it has been lost and needs to be
retransmitted. Since TCP write queue is ordered by sequence instead
of sent time, RACK has to scan over the write queue to catch all
eligible packets to detect lost retransmission, and iterates through
SACKed skbs repeatedly.

Special cares for rare events:
1. TCP repair fakes skb transmission so the send queue needs adjusted
2. SACK reneging would require re-inserting SACKed skbs into the
   send queue. For now I believe it's not worth the complexity to
   make RACK work perfectly on SACK reneging, so we do nothing here.
3. Fast Open: currently for non-TFO, send-queue correctly queues
   the pure SYN packet. For TFO which queues a pure SYN and
   then a data packet, send-queue only queues the data packet but
   not the pure SYN due to the structure of TFO code. This is okay
   because the SYN receiver would never respond with a SACK on a
   missing SYN (i.e. SYN is never fast-retransmitted by SACK/RACK).

In order to not grow sk_buff, we use an union for the new list and
_skb_refdst/destructor fields. This is a bit complicated because
we need to make sure _skb_refdst and destructor are properly zeroed
before skb is cloned/copied at transmit, and before being freed.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-05 21:24:47 -07:00
Florian Westphal 31770e34e4 tcp: Revert "tcp: remove header prediction"
This reverts commit 45f119bf93.

Eric Dumazet says:
  We found at Google a significant regression caused by
  45f119bf93 tcp: remove header prediction

  In typical RPC  (TCP_RR), when a TCP socket receives data, we now call
  tcp_ack() while we used to not call it.

  This touches enough cache lines to cause a slowdown.

so problem does not seem to be HP removal itself but the tcp_ack()
call.  Therefore, it might be possible to remove HP after all, provided
one finds a way to elide tcp_ack for most cases.

Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-30 11:20:09 -07:00
Florian Westphal 45f119bf93 tcp: remove header prediction
Like prequeue, I am not sure this is overly useful nowadays.

If we receive a train of packets, GRO will aggregate them if the
headers are the same (HP predates GRO by several years) so we don't
get a per-packet benefit, only a per-aggregated-packet one.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-31 14:37:49 -07:00
Florian Westphal e7942d0633 tcp: remove prequeue support
prequeue is a tcp receive optimization that moves part of rx processing
from bh to process context.

This only works if the socket being processed belongs to a process that
is blocked in recv on that socket.

In practice, this doesn't happen anymore that often because nowadays
servers tend to use an event driven (epoll) model.

Even normal client applications (web browsers) commonly use many tcp
connections in parallel.

This has measureable impact only in netperf (which uses plain recv and
thus allows prequeue use) from host to locally running vm (~4%), however,
there were no changes when using netperf between two physical hosts with
ixgbe interfaces.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-31 14:37:49 -07:00
Lawrence Brakmo 13d3b1ebe2 bpf: Support for setting initial receive window
This patch adds suppport for setting the initial advertized window from
within a BPF_SOCK_OPS program. This can be used to support larger
initial cwnd values in environments where it is known to be safe.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-01 16:15:13 -07:00
Eric Dumazet eed29f17f0 tcp: add a struct net parameter to tcp_parse_options()
We want to move some TCP sysctls to net namespaces in the future.

tcp_window_scaling, tcp_sack and tcp_timestamps being fetched
from tcp_parse_options(), we need to pass an extra parameter.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-08 10:53:28 -04:00
Eric Dumazet 9a568de481 tcp: switch TCP TS option (RFC 7323) to 1ms clock
TCP Timestamps option is defined in RFC 7323

Traditionally on linux, it has been tied to the internal
'jiffies' variable, because it had been a cheap and good enough
generator.

For TCP flows on the Internet, 1 ms resolution would be much better
than 4ms or 10ms (HZ=250 or HZ=100 respectively)

For TCP flows in the DC, Google has used usec resolution for more
than two years with great success [1]

Receive size autotuning (DRS) is indeed more precise and converges
faster to optimal window size.

This patch converts tp->tcp_mstamp to a plain u64 value storing
a 1 usec TCP clock.

This choice will allow us to upstream the 1 usec TS option as
discussed in IETF 97.

[1] https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 16:06:01 -04:00
Eric Dumazet ac9517fcf3 tcp: replace misc tcp_time_stamp to tcp_jiffies32
After this patch, all uses of tcp_time_stamp will require
a change when we introduce 1 ms and/or 1 us TCP TS option.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 16:06:01 -04:00
Eric Dumazet 70eabf0e1b tcp: use tcp_jiffies32 for rcv_tstamp and lrcvtime
Use tcp_jiffies32 instead of tcp_time_stamp, since
tcp_time_stamp will soon be only used for TCP TS option.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 16:06:01 -04:00
Eric Dumazet 8b485ce698 tcp: do not inherit fastopen_req from parent
Under fuzzer stress, it is possible that a child gets a non NULL
fastopen_req pointer from its parent at accept() time, when/if parent
morphs from listener to active session.

We need to make sure this can not happen, by clearing the field after
socket cloning.

BUG: Double free or freeing an invalid pointer
Unexpected shadow byte: 0xFB
CPU: 3 PID: 20933 Comm: syz-executor3 Not tainted 4.11.0+ #306
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x292/0x395 lib/dump_stack.c:52
 kasan_object_err+0x1c/0x70 mm/kasan/report.c:164
 kasan_report_double_free+0x5c/0x70 mm/kasan/report.c:185
 kasan_slab_free+0x9d/0xc0 mm/kasan/kasan.c:580
 slab_free_hook mm/slub.c:1357 [inline]
 slab_free_freelist_hook mm/slub.c:1379 [inline]
 slab_free mm/slub.c:2961 [inline]
 kfree+0xe8/0x2b0 mm/slub.c:3882
 tcp_free_fastopen_req net/ipv4/tcp.c:1077 [inline]
 tcp_disconnect+0xc15/0x13e0 net/ipv4/tcp.c:2328
 inet_child_forget+0xb8/0x600 net/ipv4/inet_connection_sock.c:898
 inet_csk_reqsk_queue_add+0x1e7/0x250
net/ipv4/inet_connection_sock.c:928
 tcp_get_cookie_sock+0x21a/0x510 net/ipv4/syncookies.c:217
 cookie_v4_check+0x1a19/0x28b0 net/ipv4/syncookies.c:384
 tcp_v4_cookie_check net/ipv4/tcp_ipv4.c:1384 [inline]
 tcp_v4_do_rcv+0x731/0x940 net/ipv4/tcp_ipv4.c:1421
 tcp_v4_rcv+0x2dc0/0x31c0 net/ipv4/tcp_ipv4.c:1715
 ip_local_deliver_finish+0x4cc/0xc20 net/ipv4/ip_input.c:216
 NF_HOOK include/linux/netfilter.h:257 [inline]
 ip_local_deliver+0x1ce/0x700 net/ipv4/ip_input.c:257
 dst_input include/net/dst.h:492 [inline]
 ip_rcv_finish+0xb1d/0x20b0 net/ipv4/ip_input.c:396
 NF_HOOK include/linux/netfilter.h:257 [inline]
 ip_rcv+0xd8c/0x19c0 net/ipv4/ip_input.c:487
 __netif_receive_skb_core+0x1ad1/0x3400 net/core/dev.c:4210
 __netif_receive_skb+0x2a/0x1a0 net/core/dev.c:4248
 process_backlog+0xe5/0x6c0 net/core/dev.c:4868
 napi_poll net/core/dev.c:5270 [inline]
 net_rx_action+0xe70/0x18e0 net/core/dev.c:5335
 __do_softirq+0x2fb/0xb99 kernel/softirq.c:284
 do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:899
 </IRQ>
 do_softirq.part.17+0x1e8/0x230 kernel/softirq.c:328
 do_softirq kernel/softirq.c:176 [inline]
 __local_bh_enable_ip+0x1cf/0x1e0 kernel/softirq.c:181
 local_bh_enable include/linux/bottom_half.h:31 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:931 [inline]
 ip_finish_output2+0x9ab/0x15e0 net/ipv4/ip_output.c:230
 ip_finish_output+0xa35/0xdf0 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:246 [inline]
 ip_output+0x1f6/0x7b0 net/ipv4/ip_output.c:404
 dst_output include/net/dst.h:486 [inline]
 ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124
 ip_queue_xmit+0x9a8/0x1a10 net/ipv4/ip_output.c:503
 tcp_transmit_skb+0x1ade/0x3470 net/ipv4/tcp_output.c:1057
 tcp_write_xmit+0x79e/0x55b0 net/ipv4/tcp_output.c:2265
 __tcp_push_pending_frames+0xfa/0x3a0 net/ipv4/tcp_output.c:2450
 tcp_push+0x4ee/0x780 net/ipv4/tcp.c:683
 tcp_sendmsg+0x128d/0x39b0 net/ipv4/tcp.c:1342
 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:762
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 SYSC_sendto+0x660/0x810 net/socket.c:1696
 SyS_sendto+0x40/0x50 net/socket.c:1664
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x446059
RSP: 002b:00007faa6761fb58 EFLAGS: 00000282 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 0000000000446059
RDX: 0000000000000001 RSI: 0000000020ba3fcd RDI: 0000000000000017
RBP: 00000000006e40a0 R08: 0000000020ba4ff0 R09: 0000000000000010
R10: 0000000020000000 R11: 0000000000000282 R12: 0000000000708150
R13: 0000000000000000 R14: 00007faa676209c0 R15: 00007faa67620700
Object at ffff88003b5bbcb8, in cache kmalloc-64 size: 64
Allocated:
PID = 20909
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:513
 set_track mm/kasan/kasan.c:525 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:616
 kmem_cache_alloc_trace+0x82/0x270 mm/slub.c:2745
 kmalloc include/linux/slab.h:490 [inline]
 kzalloc include/linux/slab.h:663 [inline]
 tcp_sendmsg_fastopen net/ipv4/tcp.c:1094 [inline]
 tcp_sendmsg+0x221a/0x39b0 net/ipv4/tcp.c:1139
 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:762
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 SYSC_sendto+0x660/0x810 net/socket.c:1696
 SyS_sendto+0x40/0x50 net/socket.c:1664
 entry_SYSCALL_64_fastpath+0x1f/0xbe
Freed:
PID = 20909
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:513
 set_track mm/kasan/kasan.c:525 [inline]
 kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:589
 slab_free_hook mm/slub.c:1357 [inline]
 slab_free_freelist_hook mm/slub.c:1379 [inline]
 slab_free mm/slub.c:2961 [inline]
 kfree+0xe8/0x2b0 mm/slub.c:3882
 tcp_free_fastopen_req net/ipv4/tcp.c:1077 [inline]
 tcp_disconnect+0xc15/0x13e0 net/ipv4/tcp.c:2328
 __inet_stream_connect+0x20c/0xf90 net/ipv4/af_inet.c:593
 tcp_sendmsg_fastopen net/ipv4/tcp.c:1111 [inline]
 tcp_sendmsg+0x23a8/0x39b0 net/ipv4/tcp.c:1139
 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:762
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 SYSC_sendto+0x660/0x810 net/socket.c:1696
 SyS_sendto+0x40/0x50 net/socket.c:1664
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Fixes: e994b2f0fb ("tcp: do not lock listener to process SYN packets")
Fixes: 7db92362d2 ("tcp: fix potential double free issue for fastopen_req")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-04 11:00:04 -04:00
Alexander Duyck e5907459ce tcp: Record Rx hash and NAPI ID in tcp_child_process
While working on some recent busy poll changes we found that child sockets
were being instantiated without NAPI ID being set.  In our first attempt to
fix it, it was suggested that we should just pull programming the NAPI ID
into the function itself since all callers will need to have it set.

In addition to the NAPI ID change I have dropped the code that was
populating the Rx hash since it was actually being populated in
tcp_get_cookie_sock.

Reported-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-24 20:49:30 -07:00
David S. Miller 16ae1f2236 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/ethernet/broadcom/genet/bcmmii.c
	drivers/net/hyperv/netvsc.c
	kernel/bpf/hashtab.c

Almost entirely overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-23 16:41:27 -07:00
Eric Dumazet 15bb7745e9 tcp: initialize icsk_ack.lrcvtime at session start time
icsk_ack.lrcvtime has a 0 value at socket creation time.

tcpi_last_data_recv can have bogus value if no payload is ever received.

This patch initializes icsk_ack.lrcvtime for active sessions
in tcp_finish_connect(), and for passive sessions in
tcp_create_openreq_child()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-22 15:39:42 -07:00
Soheil Hassas Yeganeh d82bae12dc tcp: remove per-destination timestamp cache
Commit 8a5bd45f6616 (tcp: randomize tcp timestamp offsets for each connection)
randomizes TCP timestamps per connection. After this commit,
there is no guarantee that the timestamps received from the
same destination are monotonically increasing. As a result,
the per-destination timestamp cache in TCP metrics (i.e., tcpm_ts
in struct tcp_metrics_block) is broken and cannot be relied upon.

Remove the per-destination timestamp cache and all related code
paths.

Note that this cache was already broken for caching timestamps of
multiple machines behind a NAT sharing the same address.

Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Cc: Lutz Vieweg <lvml@5t9.de>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16 20:33:56 -07:00
Alexey Kodanev eee2faabc6 tcp: account for ts offset only if tsecr not zero
We can get SYN with zero tsecr, don't apply offset in this case.

Fixes: ee684b6f28 ("tcp: send packets with a socket timestamp")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-22 16:35:58 -05:00
Eric Dumazet 3541f9e8bd tcp: add tcp_mss_clamp() helper
Small cleanup factorizing code doing the TCP_MAXSEG clamping.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-03 11:19:34 -05:00
Yuchung Cheng bec41a11dd tcp: remove early retransmit
This patch removes the support of RFC5827 early retransmit (i.e.,
fast recovery on small inflight with <3 dupacks) because it is
subsumed by the new RACK loss detection. More specifically when
RACK receives DUPACKs, it'll arm a reordering timer to start fast
recovery after a quarter of (min)RTT, hence it covers the early
retransmit except RACK does not limit itself to specific inflight
or dupack numbers.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-13 22:37:16 -05:00
Haishuang Yan 1946e672c1 ipv4: Namespaceify tcp_tw_recycle and tcp_max_tw_buckets knob
Different namespace application might require fast recycling
TIME-WAIT sockets independently of the host.

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-29 11:38:31 -05:00