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Matteo Croce e6a9d261e9 icmp: don't fail on fragment reassembly time exceeded 
[ Upstream commit 258bbb1b0e ]

The ICMP implementation currently replies to an ICMP time exceeded message
(type 11) with an ICMP host unreachable message (type 3, code 1).

However, time exceeded messages can either represent "time to live exceeded
in transit" (code 0) or "fragment reassembly time exceeded" (code 1).

Unconditionally replying to "fragment reassembly time exceeded" with
host unreachable messages might cause unjustified connection resets
which are now easily triggered as UFO has been removed, because, in turn,
sending large buffers triggers IP fragmentation.

The issue can be easily reproduced by running a lot of UDP streams
which is likely to trigger IP fragmentation:

  # start netserver in the test namespace
  ip netns add test
  ip netns exec test netserver

  # create a VETH pair
  ip link add name veth0 type veth peer name veth0 netns test
  ip link set veth0 up
  ip -n test link set veth0 up

  for i in $(seq 20 29); do
      # assign addresses to both ends
      ip addr add dev veth0 192.168.$i.1/24
      ip -n test addr add dev veth0 192.168.$i.2/24

      # start the traffic
      netperf -L 192.168.$i.1 -H 192.168.$i.2 -t UDP_STREAM -l 0 &
  done

  # wait
  send_data: data send error: No route to host (errno 113)
  netperf: send_omni: send_data failed: No route to host

We need to differentiate instead: if fragment reassembly time exceeded
is reported, we need to silently drop the packet,
if time to live exceeded is reported, maintain the current behaviour.
In both cases increment the related error count "icmpInTimeExcds".

While at it, fix a typo in a comment, and convert the if statement
into a switch to mate it more readable.

Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2017-12-20 10:10:37 +01:00
arch pinctrl: adi2: Fix Kconfig build problem 2017-12-20 10:10:34 +01:00
block blk-mq-sched: dispatch from scheduler IFF progress is made in ->dispatch 2017-12-20 10:10:27 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: tcrypt - fix buffer lengths in test_aead_speed() 2017-12-20 10:10:26 +01:00
Documentation dt-bindings: usb: fix reg-property port-number range 2017-12-14 09:53:09 +01:00
drivers IB/ipoib: Grab rtnl lock on heavy flush when calling ndo_open/stop 2017-12-20 10:10:37 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs udf: Avoid overflow when session starts at large offset 2017-12-20 10:10:36 +01:00
include IB/core: Fix endianness annotation in rdma_is_multicast_addr() 2017-12-20 10:10:36 +01:00
init License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel PM / s2idle: Clear the events_check_enabled flag 2017-12-20 10:10:23 +01:00
lib dynamic-debug-howto: fix optional/omitted ending line number to be LARGE instead of 0 2017-12-14 09:53:08 +01:00
mm mm, oom_reaper: fix memory corruption 2017-12-20 10:10:18 +01:00
net icmp: don't fail on fragment reassembly time exceeded 2017-12-20 10:10:37 +01:00
samples samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1 2017-12-20 10:10:31 +01:00
scripts kbuild: rpm-pkg: fix jobserver unavailable warning 2017-12-14 09:53:13 +01:00
security apparmor: fix leak of null profile name if profile allocation fails 2017-12-14 09:53:06 +01:00
sound ASoC: rsnd: rsnd_ssi_run_mods() needs to care ssi_parent_mod 2017-12-20 10:10:28 +01:00
tools usbip: prevent vhci_hcd driver from leaking a socket pointer address 2017-12-20 10:10:19 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: arm/arm64: vgic-its: Preserve the revious read from the pending table 2017-12-17 15:07:59 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2017-11-09 18:26:51 -08:00
Makefile Linux 4.14.7 2017-12-17 15:08:14 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.