From 23ac49bf8373ab2cd1f04d6e4bce899ac7b73187 Mon Sep 17 00:00:00 2001
From: Andreas Florath <andreas@florath.net>
Date: Sat, 14 Jan 2017 15:23:22 +0000
Subject: [PATCH] Move Ubuntu specific use_tempaddr setting to ubuntu-common
 element

By default (during boot) the use_tempaddr is set to <=0 for all
up-to date kernels.  Only Ubuntu installes a sysctl setting which
sets the use_tempaddr to 2 (/etc/sysctl.d/10-ipv6-privacy.conf) [1].
The 80-disable-rfc3041 overwrites this setting and sets
use_tempaddr back to 0.

Because this only affects Ubuntu it makes sense to move the script
to the ubuntu-common element. The other motivation for the move is,
to clear the base element that it can be removed.

[1] https://bugs.launchpad.net/ubuntu/+source/procps/+bug/1068756

Change-Id: Ibf261818ca8243874fde9eb3650bb65188fa228d
Signed-off-by: Andreas Florath <andreas@florath.net>
---
 elements/ubuntu-common/README.rst                    |  5 +++++
 .../install.d/80-disable-rfc3041                     | 12 +++++++++++-
 elements/ubuntu-core/element-deps                    |  1 +
 elements/ubuntu-minimal/element-deps                 |  1 +
 elements/ubuntu/element-deps                         |  1 +
 5 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 elements/ubuntu-common/README.rst
 rename elements/{base => ubuntu-common}/install.d/80-disable-rfc3041 (64%)

diff --git a/elements/ubuntu-common/README.rst b/elements/ubuntu-common/README.rst
new file mode 100644
index 000000000..c50160bd6
--- /dev/null
+++ b/elements/ubuntu-common/README.rst
@@ -0,0 +1,5 @@
+ubuntu-common
+=============
+
+This element holds configuration and scripts that are common for all
+Ubuntu images.
diff --git a/elements/base/install.d/80-disable-rfc3041 b/elements/ubuntu-common/install.d/80-disable-rfc3041
similarity index 64%
rename from elements/base/install.d/80-disable-rfc3041
rename to elements/ubuntu-common/install.d/80-disable-rfc3041
index b57ccbfbe..af671c234 100755
--- a/elements/base/install.d/80-disable-rfc3041
+++ b/elements/ubuntu-common/install.d/80-disable-rfc3041
@@ -21,7 +21,17 @@ if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
 fi
 set -e
 
-# This will disable the disable Privacy extensions for IPv6 (RFC3041)
+# This will disable the privacy extensions for IPv6 (RFC4941)
+# (RFC4941 obsoletes RFC3041)
+#
+# Note that depending on the implementation of how the sysctl
+# settings are applied there is a race condition: there might be
+# a small time-frame where the original Ubuntu settings from
+# /etc/sysctl.d/10-ipv6-privacy.conf are already applied but the
+# new settings from /etc/sysctl.d/99-cloudimg-ipv6.conf
+# not yet.
+# If during this time all started network interfaces will
+# use the privacy extension.
 cat > /etc/sysctl.d/99-cloudimg-ipv6.conf <<EOF
 # See https://bugs.launchpad.net/ubuntu/+source/procps/+bug/1068756
 net.ipv6.conf.all.use_tempaddr=0
diff --git a/elements/ubuntu-core/element-deps b/elements/ubuntu-core/element-deps
index 0617448fd..ca0451a09 100644
--- a/elements/ubuntu-core/element-deps
+++ b/elements/ubuntu-core/element-deps
@@ -1,3 +1,4 @@
 cache-url
 dib-run-parts
 dpkg
+ubuntu-common
diff --git a/elements/ubuntu-minimal/element-deps b/elements/ubuntu-minimal/element-deps
index e078fde1f..c952da997 100644
--- a/elements/ubuntu-minimal/element-deps
+++ b/elements/ubuntu-minimal/element-deps
@@ -1,2 +1,3 @@
 debootstrap
 package-installs
+ubuntu-common
diff --git a/elements/ubuntu/element-deps b/elements/ubuntu/element-deps
index c575e9090..d57d5e7eb 100644
--- a/elements/ubuntu/element-deps
+++ b/elements/ubuntu/element-deps
@@ -3,3 +3,4 @@ cloud-init-datasources
 dib-run-parts
 dkms
 dpkg
+ubuntu-common