Create a networking service script, so we can run it after switchd

Ticket: CM-8790
Reviewed By: wkok,roopa
Testing Done: built, installed, rebooted

jessie's networking starts as an init.d service.   Trying to force ordering
between init.d and systemd services when there are dependencies doesn't work
well (especially since the init.d/networking service is forced very early
because of the remote filesystem requirement in jesie).

Converting networking to a script run as a systemd service allows us to start
networking after switchd.  The new script is /sbin/start-networking.  I chose
to keep it in /sbin, rather than put it in /usr/cumulus/bin, because it's core
functionaity.

I am not removing /etc/init.d/networking, it just gets ignored unless somebody
types it manually.  If somebody does that, systemctl runs through the lsb
hooks.  The two lost abilities below are just ignored if passed.  I'm
also preventing creating the rc.d symlinks to the init.d/networking
script to reduce future confusion.

We lose some init.d "convenience" functionality because it's not available
through systemd.  What we lose are:
  reload-currently-up - can still be done with ifreload --currently-up
  force-reload - can still be done with ifreload -f -a
We keep start, stop, reload, restart

debian/ifupdown2.install

@@ -1,2 +1,3 @@
 sbin/ifupdown2 /usr/share/ifupdown2/
+sbin/start-networking /sbin
 debian/networking.default /etc/default/networking

debian/ifupdown2.networking.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=Cumulus Linux networking initialization
+After=switchd.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+SyslogIdentifier=networking
+TimeoutSec=60s
+TimeoutStopSec=30s
+ExecStart=/sbin/start-networking start
+ExecStop=/sbin/start-networking stop
+ExecReload=/sbin/start-networking reload
+
+[Install]
+WantedBy=basic.target network.target

debian/rules

@@ -5,12 +5,19 @@ export PYBUILD_NAME=ifupdown2
 export PYBUILD_INSTALL_ARGS=--install-lib=/usr/share/ifupdown2 --install-scripts=/usr/share/ifupdown2
 
 %:
-	dh $@ --with python2 --buildsystem=pybuild
+	dh $@ --with python2 --with systemd --buildsystem=pybuild
 
 override_dh_installman:
 	./scripts/genmanpages.sh ./man.rst ./man
 	dh_installman
 
-override_dh_installinit:
+override_dh_systemd_start:
+	dh_systemd_start --name=networking --no-start
+
+override_dh_systemd_enable:
 	dh_systemd_enable --name=networking
-	dh_installinit --name=networking --no-start
+
+# init.d/networking is installed, but we don't want any symlinks; it's
+# never used by anything, so avoid the confusion of the symlinks.
+override_dh_installinit:
+	dh_installinit --name=networking --no-start -uremove networking.init

sbin/start-networking

@@ -0,0 +1,144 @@
+#!/bin/bash
+
+# This overrides /etc/init.d/networking
+# Only has start, stop, reload, because that's all systemd has.
+# restart is implemented in systemd by stop then start.
+
+PATH="/sbin:/bin"
+RUN_DIR="/run/network"
+IFSTATE="$RUN_DIR/ifstate"
+
+NAME=networking
+
+[ -x /sbin/ifup ] || exit 0
+[ -x /sbin/ifdown ] || exit 0
+
+CONFIGURE_INTERFACES=yes
+
+EXTRA_ARGS=
+
+[ -f /etc/default/networking ] && . /etc/default/networking
+
+[ "$VERBOSE" = yes ] && EXTRA_ARGS=-v
+[ "$DEBUG" = yes ] && EXTRA_ARGS="$EXTRA_ARGS -d"
+[ "$SYSLOG" = yes ] && EXTRA_ARGS="$EXTRA_ARGS --syslog"
+
+perf_options() {
+    # At bootup lets set perfmode
+    [ -f /var/tmp/network/ifstatenew ] && echo -n "" && return
+
+    echo -n "--perfmode"
+}
+
+process_exclusions() {
+    set -- $EXCLUDE_INTERFACES
+    exclusions=""
+    for d
+    do
+	exclusions="-X $d $exclusions"
+    done
+    echo $exclusions
+}
+
+check_network_file_systems() {
+    [ -e /proc/mounts ] || return 0
+
+    if [ -e /etc/iscsi/iscsi.initramfs ]; then
+	echo ${NAME}':' "not deconfiguring network interfaces: iSCSI root is mounted."
+	exit 0
+    fi
+
+    while read DEV MTPT FSTYPE REST; do
+	case $DEV in
+	/dev/nbd*|/dev/nd[a-z]*|/dev/etherd/e*)
+	    echo ${NAME}':' "not deconfiguring network interfaces: network devices still mounted."
+	    exit 0
+	    ;;
+	esac
+	case $FSTYPE in
+	nfs|nfs4|smbfs|ncp|ncpfs|cifs|coda|ocfs2|gfs|pvfs|pvfs2|fuse.httpfs|fuse.curlftpfs)
+	    echo ${NAME}':' "not deconfiguring network interfaces: network file systems still mounted."
+	    exit 0
+	    ;;
+	esac
+    done < /proc/mounts
+}
+
+check_network_swap() {
+    [ -e /proc/swaps ] || return 0
+
+    while read DEV MTPT FSTYPE REST; do
+	case $DEV in
+	/dev/nbd*|/dev/nd[a-z]*|/dev/etherd/e*)
+	    echo ${NAME}':' "not deconfiguring network interfaces: network swap still mounted."
+	    exit 0
+	    ;;
+	esac
+    done < /proc/swaps
+}
+
+ifup_hotplug () {
+    if [ -d /sys/class/net ]
+    then
+	    ifaces=$(for iface in $(ifquery --list --allow=hotplug 2>/dev/null)
+			    do
+				    link=${iface##:*}
+				    link=${link##.*}
+				    if [ -e "/sys/class/net/$link" ] && [ "$(cat /sys/class/net/$link/operstate)" = up ]
+				    then
+					    echo "$iface"
+				    fi
+			    done)
+	    if [ -n "$ifaces" ]
+	    then
+		ifup $ifaces "$@" || true
+	    fi
+    fi
+}
+
+ifupdown_init() {
+	[ ! -e /run/network ] && mkdir -p /run/network &>/dev/null
+	[ ! -e /etc/network/run ] && \
+		ln -sf /run/network /etc/network/run &>/dev/null
+}
+
+case "$1" in
+start)
+	ifupdown_init
+	if [ "$CONFIGURE_INTERFACES" = no ]
+	then
+	    echo ${NAME}':' "Not configuring network interfaces, see /etc/default/networking"
+	    exit 0
+	fi
+	set -f
+	exclusions=$(process_exclusions)
+	perfoptions=$(perf_options)
+	echo ${NAME}':' "Configuring network interfaces"
+	ifup -a $EXTRA_ARGS $exclusions $perfoptions
+	;;
+
+stop)
+	ifupdown_init
+	check_network_file_systems
+	check_network_swap
+	exclusions=$(process_exclusions)
+
+	echo ${NAME}':' "Deconfiguring network interfaces"
+	ifdown -a $EXTRA_ARGS
+	;;
+
+reload)
+
+	ifupdown_init
+	echo ${NAME}':' "Reloading network interfaces configuration"
+
+	ifreload -a $EXTRA_ARGS
+	;;
+
+*)
+	echo ${NAME}':' "Usage: $0 {start|stop|reload}"
+	exit 1
+	;;
+esac
+
+exit 0