linux-toradex.git/Documentation/networking, branch v4.0

Merge tag 'docs-for-linus' of git://git.lwn.net/linux-2.6

2015-02-11T21:03:11+00:00

Pull documentation updates from Jonathan Corbet:
 "Highlights this time around include:

   - A thrashing of SubmittingPatches to bring it out of the "send
     everything to Linus" era of kernel development.

   - A new document on completions from Nicholas McGuire

   - Lots of typo fixes, formatting improvements, corrections, build
     fixes, and more"

* tag 'docs-for-linus' of git://git.lwn.net/linux-2.6: (35 commits)
  Documentation: Fix the wrong command `echo -1 > set_ftrace_pid` for cleaning the filter.
  can-doc: Fixed a wrong filepath in can.txt
  Documentation: Fix trivial typo in comment.
  kgdb,docs: Fix typo and minor style issues
  Documentation: add description for FTRACE probe status
  doc: brief user documentation for completion
  Documentation/misc-devices/mei: Fix indentation of embedded code.
  Documentation/misc-devices/mei: Fix indentation of enumeration.
  Documentation/misc-devices/mei: Fix spacing around parentheses.
  Documentation/misc-devices/mei: Fix formatting of headings.
  Documentation: devicetree: Fix double words in Doumentation/devicetree
  Documentation: mm: Fix typo in vm.txt
  lockstat: Add documentation on contention and contenting points
  Documentation: fix blackfin gptimers-example build errors
  Fixes column alignment in table of contents entry 1.9 in Documentation/filesystems/proc.txt
  CodingStyle: enable emacs display of trailing whitespace
  DocBook: Do not exceed argument list limit
  gpio: board.txt: Fix the gpio name example
  Documentation/SubmittingPatches: unify whitespace/tabs for the DCO
  MAINTAINERS: Add the docs-next git tree to the maintainer entry
  ...

tcp: helpers to mitigate ACK loops by rate-limiting out-of-window dupacks

2015-02-08T09:03:12+00:00

Helpers for mitigating ACK loops by rate-limiting dupacks sent in
response to incoming out-of-window packets.

This patch includes:

- rate-limiting logic
- sysctl to control how often we allow dupacks to out-of-window packets
- SNMP counter for cases where we rate-limited our dupack sending

The rate-limiting logic in this patch decides to not send dupacks in
response to out-of-window segments if (a) they are SYNs or pure ACKs
and (b) the remote endpoint is sending them faster than the configured
rate limit.

We rate-limit our responses rather than blocking them entirely or
resetting the connection, because legitimate connections can rely on
dupacks in response to some out-of-window segments. For example, zero
window probes are typically sent with a sequence number that is below
the current window, and ZWPs thus expect to thus elicit a dupack in
response.

We allow dupacks in response to TCP segments with data, because these
may be spurious retransmissions for which the remote endpoint wants to
receive DSACKs. This is safe because segments with data can't
realistically be part of ACK loops, which by their nature consist of
each side sending pure/data-less ACKs to each other.

The dupack interval is controlled by a new sysctl knob,
tcp_invalid_ratelimit, given in milliseconds, in case an administrator
needs to dial this upward in the face of a high-rate DoS attack. The
name and units are chosen to be analogous to the existing analogous
knob for ICMP, icmp_ratelimit.

The default value for tcp_invalid_ratelimit is 500ms, which allows at
most one such dupack per 500ms. This is chosen to be 2x faster than
the 1-second minimum RTO interval allowed by RFC 6298 (section 2, rule
2.4). We allow the extra 2x factor because network delay variations
can cause packets sent at 1 second intervals to be compressed and
arrive much closer.

Reported-by: Avery Fay 
Signed-off-by: Neal Cardwell 
Signed-off-by: Yuchung Cheng 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

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

2015-02-05T22:33:28+00:00

Conflicts:
	drivers/net/vxlan.c
	drivers/vhost/net.c
	include/linux/if_vlan.h
	net/core/dev.c

The net/core/dev.c conflict was the overlap of one commit marking an
existing function static whilst another was adding a new function.

In the include/linux/if_vlan.h case, the type used for a local
variable was changed in 'net', whereas the function got rewritten
to fix a stacked vlan bug in 'net-next'.

In drivers/vhost/net.c, Al Viro's iov_iter conversions in 'net-next'
overlapped with an endainness fix for VHOST 1.0 in 'net'.

In drivers/net/vxlan.c, vxlan_find_vni() added a 'flags' parameter
in 'net-next' whereas in 'net' there was a bug fix to pass in the
correct network namespace pointer in calls to this function.

Signed-off-by: David S. Miller

can-doc: Fixed a wrong filepath in can.txt

2015-02-05T14:59:44+00:00

 moved in the big UAPI shuffle; update the document to
note its new location.

Signed-off-by: Stefan Tatschner 
[jc: added changelog]
Signed-off-by: Jonathan Corbet

Documentation: Update netlink_mmap.txt

2015-02-03T02:50:00+00:00

Update netlink_mmap.txt wrt. commit 4682a0358639b29cf
("netlink: Always copy on mmap TX.").

Signed-off-by: Richard Weinberger 
Signed-off-by: David S. Miller

net-timestamp: no-payload option in txtimestamp test

2015-02-03T02:46:51+00:00

Demonstrate how SOF_TIMESTAMPING_OPT_TSONLY can be used and
test the implementation.

Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller

net-timestamp: no-payload option

2015-02-03T02:46:51+00:00

Add timestamping option SOF_TIMESTAMPING_OPT_TSONLY. For transmit
timestamps, this loops timestamps on top of empty packets.

Doing so reduces the pressure on SO_RCVBUF. Payload inspection and
cmsg reception (aside from timestamps) are no longer possible. This
works together with a follow on patch that allows administrators to
only allow tx timestamping if it does not loop payload or metadata.

Signed-off-by: Willem de Bruijn 

----

Changes (rfc -> v1)
  - add documentation
  - remove unnecessary skb->len test (thanks to Richard Cochran)
Signed-off-by: David S. Miller

openvswitch: Add support for unique flow IDs.

2015-01-26T23:45:50+00:00

Previously, flows were manipulated by userspace specifying a full,
unmasked flow key. This adds significant burden onto flow
serialization/deserialization, particularly when dumping flows.

This patch adds an alternative way to refer to flows using a
variable-length "unique flow identifier" (UFID). At flow setup time,
userspace may specify a UFID for a flow, which is stored with the flow
and inserted into a separate table for lookup, in addition to the
standard flow table. Flows created using a UFID must be fetched or
deleted using the UFID.

All flow dump operations may now be made more terse with OVS_UFID_F_*
flags. For example, the OVS_UFID_F_OMIT_KEY flag allows responses to
omit the flow key from a datapath operation if the flow has a
corresponding UFID. This significantly reduces the time spent assembling
and transacting netlink messages. With all OVS_UFID_F_OMIT_* flags
enabled, the datapath only returns the UFID and statistics for each flow
during flow dump, increasing ovs-vswitchd revalidator performance by 40%
or more.

Signed-off-by: Joe Stringer 
Acked-by: Pravin B Shelar 
Signed-off-by: David S. Miller

net: ipv6: Add sysctl entry to disable MTU updates from RA

2015-01-25T22:54:41+00:00

The kernel forcefully applies MTU values received in router
advertisements provided the new MTU is less than the current. This
behavior is undesirable when the user space is managing the MTU. Instead
a sysctl flag 'accept_ra_mtu' is introduced such that the user space
can control whether or not RA provided MTU updates should be applied. The
default behavior is unchanged; user space must explicitly set this flag
to 0 for RA MTUs to be ignored.

Signed-off-by: Harout Hedeshian 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next

2015-01-15T06:50:25+00:00

Pablo Neira Ayuso says:

====================
netfilter updates for net-next

The following patchset contains netfilter updates for net-next, just a
bunch of cleanups and small enhancement to selectively flush conntracks
in ctnetlink, more specifically the patches are:

1) Rise default number of buckets in conntrack from 16384 to 65536 in
   systems with >= 4GBytes, patch from Marcelo Leitner.

2) Small refactor to save one level on indentation in xt_osf, from
   Joe Perches.

3) Remove unnecessary sizeof(char) in nf_log, from Fabian Frederick.

4) Another small cleanup to remove redundant variable in nfnetlink,
   from Duan Jiong.

5) Fix compilation warning in nfnetlink_cthelper on parisc, from
   Chen Gang.

6) Fix wrong format in debugging for ctseqadj, from Gao feng.

7) Selective conntrack flushing through the mark for ctnetlink, patch
   from Kristian Evensen.

8) Remove nf_ct_conntrack_flush_report() exported symbol now that is
   not required anymore after the selective flushing patch, again from
   Kristian.
====================

Signed-off-by: David S. Miller