linux.git/Documentation/networking/ip-sysctl.txt, branch v4.18

docs: networking: fix minor typos in various documentation files

2018-06-04T21:21:28+00:00

This patch fixes some typos/misspelling errors in the
Documentation/networking files.

Signed-off-by: Olivier Gayot 
Signed-off-by: David S. Miller

net-tcp: extend tcp_tw_reuse sysctl to enable loopback only optimization

2018-06-04T21:13:35+00:00

This changes the /proc/sys/net/ipv4/tcp_tw_reuse from a boolean
to an integer.

It now takes the values 0, 1 and 2, where 0 and 1 behave as before,
while 2 enables timewait socket reuse only for sockets that we can
prove are loopback connections:
  ie. bound to 'lo' interface or where one of source or destination
  IPs is 127.0.0.0/8, ::ffff:127.0.0.0/104 or ::1.

This enables quicker reuse of ephemeral ports for loopback connections
- where tcp_tw_reuse is 100% safe from a protocol perspective
(this assumes no artificially induced packet loss on 'lo').

This also makes estblishing many loopback connections *much* faster
(allocating ports out of the first half of the ephemeral port range
is significantly faster, then allocating from the second half)

Without this change in a 32K ephemeral port space my sample program
(it just establishes and closes [::1]:ephemeral -> [::1]:server_port
connections in a tight loop) fails after 32765 connections in 24 seconds.
With it enabled 50000 connections only take 4.7 seconds.

This is particularly problematic for IPv6 where we only have one local
address and cannot play tricks with varying source IP from 127.0.0.0/8
pool.

Signed-off-by: Maciej Żenczykowski 
Cc: Neal Cardwell 
Cc: Yuchung Cheng 
Cc: Wei Wang 
Change-Id: I0377961749979d0301b7b62871a32a4b34b654e1
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: add tcp_comp_sack_nr sysctl

2018-05-18T15:40:27+00:00

This per netns sysctl allows for TCP SACK compression fine-tuning.

This limits number of SACK that can be compressed.
Using 0 disables SACK compression.

Signed-off-by: Eric Dumazet 
Acked-by: Neal Cardwell 
Signed-off-by: David S. Miller

tcp: add tcp_comp_sack_delay_ns sysctl

2018-05-18T15:40:27+00:00

This per netns sysctl allows for TCP SACK compression fine-tuning.

Its default value is 1,000,000, or 1 ms to meet TSO autosizing period.

Signed-off-by: Eric Dumazet 
Acked-by: Neal Cardwell 
Signed-off-by: David S. Miller

tcp: disable RFC6675 loss detection

2018-05-17T19:41:28+00:00

This patch disables RFC6675 loss detection and make sysctl
net.ipv4.tcp_recovery = 1 controls a binary choice between RACK
(1) or RFC6675 (0).

Signed-off-by: Yuchung Cheng 
Signed-off-by: Neal Cardwell 
Reviewed-by: Eric Dumazet 
Reviewed-by: Soheil Hassas Yeganeh 
Reviewed-by: Priyaranjan Jha 
Signed-off-by: David S. Miller

tcp: support DUPACK threshold in RACK

2018-05-17T19:41:28+00:00

This patch adds support for the classic DUPACK threshold rule
(#DupThresh) in RACK.

When the number of packets SACKed is greater or equal to the
threshold, RACK sets the reordering window to zero which would
immediately mark all the unsacked packets below the highest SACKed
sequence lost. Since this approach is known to not work well with
reordering, RACK only uses it if no reordering has been observed.

The DUPACK threshold rule is a particularly useful extension to the
fast recoveries triggered by RACK reordering timer. For example
data-center transfers where the RTT is much smaller than a timer
tick, or high RTT path where the default RTT/4 may take too long.

Note that this patch differs slightly from RFC6675. RFC6675
considers a packet lost when at least #DupThresh higher-sequence
packets are SACKed.

With RACK, for connections that have seen reordering, RACK
continues to use a dynamically-adaptive time-based reordering
window to detect losses. But for connections on which we have not
yet seen reordering, this patch considers a packet lost when at
least one higher sequence packet is SACKed and the total number
of SACKed packets is at least DupThresh. For example, suppose a
connection has not seen reordering, and sends 10 packets, and
packets 3, 5, 7 are SACKed. RFC6675 considers packets 1 and 2
lost. RACK considers packets 1, 2, 4, 6 lost.

There is some small risk of spurious retransmits here due to
reordering. However, this is mostly limited to the first flight of
a connection on which the sender receives SACKs from reordering.
And RFC 6675 and FACK loss detection have a similar risk on the
first flight with reordering (it's just that the risk of spurious
retransmits from reordering was slightly narrower for those older
algorithms due to the margin of 3*MSS).

Also the minimum reordering window is reduced from 1 msec to 0
to recover quicker on short RTT transfers. Therefore RACK is more
aggressive in marking packets lost during recovery to reduce the
reordering window timeouts.

Signed-off-by: Yuchung Cheng 
Signed-off-by: Neal Cardwell 
Reviewed-by: Eric Dumazet 
Reviewed-by: Soheil Hassas Yeganeh 
Reviewed-by: Priyaranjan Jha 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-05-04T13:58:56+00:00

Overlapping changes in selftests Makefile.

Signed-off-by: David S. Miller

ipv6: sr: Add documentation for seg_flowlabel sysctl

2018-04-28T00:23:56+00:00

This patch adds a documentation for seg_flowlabel sysctl into
Documentation/networking/ip-sysctl.txt

Signed-off-by: Ahmed Abdelsalam 
Signed-off-by: David S. Miller

Merge tag 'staging-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

2018-04-27T16:37:12+00:00

Pull staging fixes from Greg KH:
 "Here are two staging driver fixups for 4.17-rc3.

  The first is the remaining stragglers of the irda code removal that
  you pointed out during the merge window. The second is a fix for the
  wilc1000 driver due to a patch that got merged in 4.17-rc1.

  Both of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: wilc1000: fix NULL pointer exception in host_int_parse_assoc_resp_info()
  staging: irda: remove remaining remants of irda code removal

docs: ip-sysctl.txt: fix name of some ipv6 variables

2018-04-19T19:20:09+00:00

The name of the following proc/sysctl entries were incorrectly
documented:

    /proc/sys/net/ipv6/conf//max_dst_opts_number
    /proc/sys/net/ipv6/conf//max_hbt_opts_number
    /proc/sys/net/ipv6/conf//max_dst_opts_length
    /proc/sys/net/ipv6/conf//max_hbt_length

Their name was set to the name of the symbol in the .data field of the
control table instead of their .proc name.

Signed-off-by: Olivier Gayot 
Signed-off-by: David S. Miller