gluon-offline-ssid: add original gluon-ssid-changer package to automatically change the SSID when no Internet connection

docs/package/gluon-ssid-changer.rst

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+gluon-ssid-changer
+==================
+
+This package adds a script to change the SSID when there is no connection to any
+gateway. This Offline-SSID can be generated from the node's hostname with the
+first and last part of the node name or the MAC address allowing observers to
+recognize which node does not have a connection to a gateway. This script is
+called once every minute by ``micron.d`` and check gateway-connectivity. It will
+change the SSID to the Offline-SSID after the node lost gateway connectivity for
+several consecutive checks. As soon as the gateway-connectivity is back it
+toggles back to the original SSID.
+
+You can enable/disable it in the config mode.
+
+It checks if a gateway is reachable in an interval. Different algorithms can be
+selected to determine whether a gateway is reachable:
+
+-  ``tq_limit_enabled=true``: (not working with BATMAN\_V) define an upper and
+   lower bound to toggle the SSID. As long as the TQ stays in-between those
+   bounds the SSID will not be changed.
+-  ``tq_limit_enabled=false``: there will be only checked, if the gateway is
+   reachable with:
+
+   ::
+
+       batctl gwl -H
+
+The SSID is always changed back to normal every minute as soon as the
+gateway-connectivity is back, The parameter ``switch_timeframe`` defines how
+long it will record the gateway-connectivity. **Only** if the gateway is not
+reachable during at least half the checks within ``switch_timeframe`` minutes,
+the SSID will be changed to "FF\_Offline\_$node\_hostname".
+
+The parameter ``first`` defines a learning phase after reboot (in minutes)
+during which the SSID may be changed to the Offline-SSID **every minute**.
+
+site.conf
+=========
+
+Adapt and add this block to your ``site.conf``:
+
+::
+
+    ssid_changer = {
+      enabled = true,
+      switch_timeframe = 30,    -- only once every timeframe (in minutes) the SSID will change to the Offline-SSID 
+                                -- set to 1440 to change once a day
+                                -- set to 1 minute to change every time the router gets offline
+      first = 5,                -- the first few minutes directly after reboot within which an Offline-SSID may be
+                                -- activated every minute (must be <= switch_timeframe)
+      prefix = 'FF_Offline_',   -- use something short to leave space for the nodename (no '~' allowed!)
+      suffix = 'nodename',      -- generate the SSID with either 'nodename', 'mac' or to use only the prefix: 'none'
+      
+      tq_limit_enabled = false, -- if false, the offline SSID will only be set if there is no gateway reacheable
+                                -- upper and lower limit to turn the offline_ssid on and off
+                                -- in-between these two values the SSID will never be changed to prevent it from
+                                -- toggeling every minute.
+      tq_limit_max = 45,        -- upper limit, above that the online SSID will be used
+      tq_limit_min = 35         -- lower limit, below that the offline SSID will be used
+    },
+
+Commandline options
+===================
+
+You can configure the ssid-changer on the commandline with ``uci``, for example
+disable it with:
+
+::
+
+    uci set ssid-changer.settings.enabled='0'
+
+Or set the timeframe to every three minutes with
+
+::
+
+    uci set ssid-changer.settings.switch_timeframe='3'
+    uci set ssid-changer.settings.first='3'

package/gluon-ssid-changer/Makefile

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+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=gluon-ssid-changer
+PKG_VERSION:=5
+
+include $(TOPDIR)/../package/gluon.mk
+
+define Package/$(PKG_NAME)
+  TITLE:=changes the SSID to an Offline-SSID so clients don't connect to an offline WiFi
+  DEPENDS:=+gluon-core +micrond
+endef
+
+define Package/$(PKG_NAME)/description
+  Script to change the SSID to an Offline-SSID when there is no connection to
+  any gateway. This SSID can be generated from the node's hostname with the
+  first and last part of the nodename or the mac address, to allow observers to 
+  recognise which node is down. The script is called once a minute by micrond
+  and it will change from online to Offline-SSID once per definable timeframe at
+  most.
+endef
+
+
+define Build/Compile
+	$(call Gluon/Build/Compile)
+	./gluonShellDiet.sh shsrc/ssid-changer.sh > $(PKG_BUILD_DIR)/ssid-changer.sh
+endef
+
+define Package/$(PKG_NAME)/install
+	$(Gluon/Build/Install)
+
+	$(INSTALL_DIR) $(1)/lib/gluon/ssid-changer
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/ssid-changer.sh $(1)/lib/gluon/ssid-changer/
+endef
+
+
+$(eval $(call BuildPackageGluon,$(PKG_NAME)))

package/gluon-ssid-changer/check_site.lua

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+need_boolean({'ssid_changer', 'enabled'}, false)
+need_number({'ssid_changer', 'switch_timeframe'}, false)
+need_number({'ssid_changer', 'first'}, false)
+need_string({'ssid_changer', 'prefix'}, false)
+need_one_of({'ssid_changer', 'suffix'}, {'nodename', 'mac', 'none'}, false)
+if need_boolean({'ssid_changer','tq_limit_enabled'}, false) then
+  need_number({'ssid_changer', 'tq_limit_max'}, false)
+  need_number({'ssid_changer', 'tq_limit_min'}, false)
+end

package/gluon-ssid-changer/files/etc/config/ssid-changer

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+config settings 'settings'

package/gluon-ssid-changer/files/usr/lib/micron.d/ssid-changer

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+* * * * * /lib/gluon/ssid-changer/ssid-changer.sh

package/gluon-ssid-changer/gluonShellDiet.sh

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+#!/bin/sh
+
+# This script requires a file as argument in which it will remove all comment lines that start with a hash '#'
+
+sed '/^\s*\#[^!].*/d; /^\s*\#$/d' $1

package/gluon-ssid-changer/i18n/de.po

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+msgid ""
+msgstr ""
+"Project-Id-Version: PACKAGE VERSION\n"
+"PO-Revision-Date: 2018-07-29 15:26+0200\n"
+"Last-Translator:  <github@r.z11.de>\n"
+"Language-Team: German\n"
+"Language: de\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+msgid "Enabled"
+msgstr "Aktiviert"
+
+msgid ""
+"Here you can enable to automatically change the SSID to the Offline-SSID "
+"when the node has no connection to the selected Gateway."
+msgstr ""
+"Hier kannst du aktivieren, dass dein Knoten automatisch die SSID auf die "
+"Offline-SSID ändert, wenn keine Verbindung zu Freifunk Servern besteht.<br /><br />"
+"Das verhindert, dass Client-Geräte sich mit einem Knoten verbinden, an dem es "
+"derzeit keine nutzbare Interverbindung gibt.<br />"
+"Wenn in dieser Firmware der Suffix auf 'nodename' gestellt ist, dann kann man "
+"leichter anhand der dann gesendeten Offline-SSID nach einem fehlerhaften Gerät "
+"suchen."

package/gluon-ssid-changer/i18n/gluon-ssid-changer.pot

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+msgid ""
+msgstr "Content-Type: text/plain; charset=UTF-8"
+
+msgid "Enabled"
+msgstr ""
+
+msgid ""
+"Here you can enable to automatically change the SSID to the Offline-SSID "
+"when the node has no connection to the selected Gateway."
+msgstr ""

package/gluon-ssid-changer/luasrc/lib/gluon/config-mode/controller/admin/ssid-changer.lua

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+entry({"admin", "ssid-changer"}, model("admin/ssid-changer"), _("Offline-SSID"), 35)

package/gluon-ssid-changer/luasrc/lib/gluon/config-mode/model/admin/ssid-changer.lua

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+local uci = require('simple-uci').cursor()
+local util = require 'gluon.util'
+
+local pkg_i18n = i18n 'gluon-ssid-changer'
+
+local f = Form(pkg_i18n.translate('Offline-SSID'))
+
+local s = f:section(Section, nil, pkg_i18n.translate(
+	'Here you can enable to automatically change the SSID to the Offline-SSID '
+	.. 'when the node has no connection to the selected Gateway.'
+))
+
+local enabled = s:option(Flag, 'enabled', pkg_i18n.translate('Enabled'))
+enabled.default = uci:get_bool('ssid-changer', 'settings', 'enabled')
+
+function f:write()
+	if enabled.data then
+		uci:section('ssid-changer', 'settings', 'settings', {
+			enabled = '1'
+		})
+	else
+		uci:set('ssid-changer', 'settings', 'enabled', '0')
+	end
+
+	uci:commit('ssid-changer')
+end
+
+return f

package/gluon-ssid-changer/luasrc/lib/gluon/upgrade/500-ssid-changer

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+#!/usr/bin/lua
+
+local site = require 'gluon.site'
+
+local uci = require('simple-uci').cursor()
+
+if site.ssid_changer ~= nil then
+	local site_enabled = site.ssid_changer.enabled() or '1'
+
+	uci:section('ssid-changer', 'settings', 'settings', {
+		enabled           = uci:get('ssid-changer', 'settings', 'enabled') or site_enabled,
+		switch_timeframe  = site.ssid_changer.switch_timeframe() or '30',
+		first             = site.ssid_changer.first() or '5',
+		prefix            = site.ssid_changer.prefix() or 'FF_Offline_',
+		suffix            = site.ssid_changer.suffix() or 'nodename',
+		tq_limit_enabled  = site.ssid_changer.tq_limit_enabled() or false,
+		tq_limit_max      = site.ssid_changer.tq_limit_max() or 45,
+		tq_limit_min      = site.ssid_changer.tq_limit_min() or 35,
+	})
+	uci:save('ssid-changer')
+end

package/gluon-ssid-changer/shsrc/ssid-changer.sh

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+#!/bin/sh
+
+#################
+# safety checks #
+#################
+safety_exit() {
+	echo $1, exiting with error code 2
+	exit 2
+}
+pgrep -f autoupdater >/dev/null && safety_exit 'autoupdater running'
+UT=$(sed 's/\..*//g' /proc/uptime)
+[ $UT -gt 60 ] || safety_exit 'less than one minute'
+[ $(find /var/run -name hostapd-phy* | wc -l) -gt 0 ] || safety_exit 'no hostapd-phy*'
+
+# only once every timeframe minutes the SSID will change to the Offline-SSID
+# (set to 1 minute to change immediately every time the router gets offline)
+MINUTES="$(uci -q get ssid-changer.settings.switch_timeframe)"
+: ${MINUTES:=30}
+
+# the first few minutes directly after reboot within which an Offline-SSID always may be activated
+# (must be <= switch_timeframe)
+FIRST="$(uci -q get ssid-changer.settings.first)"
+: ${FIRST:=5}
+
+# the Offline-SSID will start with this prefix use something short to leave space for the nodename
+# (no '~' allowed!)
+PREFIX="$(uci -q get ssid-changer.settings.prefix)"
+: ${PREFIX:='FF_Offline_'}
+
+if [ "$(uci -q get ssid-changer.settings.enabled)" = '0' ]; then 
+	DISABLED='1'
+else
+	DISABLED='0'
+fi
+
+# generate the ssid with either 'nodename', 'mac' or to use only the prefix set to 'none'
+SETTINGS_SUFFIX="$(uci -q get ssid-changer.settings.suffix)"
+: ${SETTINGS_SUFFIX:='nodename'}
+
+if [ $SETTINGS_SUFFIX = 'nodename' ]; then
+	SUFFIX="$(uname -n)"
+	# 32 would be possible as well
+	if [ ${#SUFFIX} -gt $((30 - ${#PREFIX})) ]; then
+		# calculate the length of the first part of the node identifier in the offline-ssid
+		HALF=$(( (28 - ${#PREFIX} ) / 2 ))
+		# jump to this charakter for the last part of the name
+		SKIP=$(( ${#SUFFIX} - $HALF ))
+		# use the first and last part of the nodename for nodes with long name
+		SUFFIX=${SUFFIX:0:$HALF}...${SUFFIX:$SKIP:${#SUFFIX}}
+	fi
+elif [ $SETTINGS_SUFFIX = 'mac' ]; then
+	SUFFIX="$(uci -q get network.bat0.macaddr | /bin/sed 's/://g')"
+else
+	# 'none'
+	SUFFIX=''
+fi
+
+OFFLINE_SSID="$PREFIX$SUFFIX"
+
+# get all SSIDs (replace \' with TICX and back to keep a possible tic in an SSID)
+ONLINE_SSIDs="$(uci show | grep wireless.client_radio[0-9]\. | grep ssid  | awk -F '='  '{print $2}' | sed "s/\\\'/TICX/g" | tr \' \~ | sed "s/TICX/\\\'/g" ) "
+# if for whatever reason ONLINE_SSIDs is NULL:
+: ${ONLINE_SSIDs:="~FREIFUNK~"}
+
+# temp file to count the offline incidents during switch_timeframe
+TMP=/tmp/ssid-changer-count
+if [ ! -f $TMP ]; then echo "0">$TMP; fi
+OFF_COUNT=$(cat $TMP)
+
+TQ_LIMIT_ENABLED="$(uci -q get ssid-changer.settings.tq_limit_enabled)"
+# if true, the offline ssid will only be set if there is no gateway reacheable
+# upper and lower limit to turn the offline_ssid on and off
+# in-between these two values the SSID will never be changed to preven it from toggeling every Minute.
+: ${TQ_LIMIT_ENABLED:='0'}
+
+if [ $TQ_LIMIT_ENABLED = 1 ]; then
+	TQ_LIMIT_MAX="$(uci -q get ssid-changer.settings.tq_limit_max)"
+	#  upper limit, above that the online SSID will be used
+	: ${TQ_LIMIT_MAX:='45'}
+	TQ_LIMIT_MIN="$(uci -q get ssid-changer.settings.tq_limit_min)"
+	#  lower limit, below that the offline SSID will be used
+	: ${TQ_LIMIT_MIN:='35'}
+	# grep the connection quality of the currently used gateway
+	GATEWAY_TQ=$(batctl gwl | grep -e "^=>" -e "^\*" | awk -F '[('')]' '{print $2}' | tr -d " ")
+	if [ ! $GATEWAY_TQ ]; then
+		# there is no gateway
+		GATEWAY_TQ=0
+	fi
+
+	MSG="TQ is $GATEWAY_TQ, "
+
+	if [ $GATEWAY_TQ -ge $TQ_LIMIT_MAX ]; then
+		CHECK=1
+	elif [ $GATEWAY_TQ -lt $TQ_LIMIT_MIN ]; then
+		CHECK=0
+	else
+		# this is just get a clean run if we are in-between the grace periode
+		echo "TQ is $GATEWAY_TQ, do nothing"
+		exit 0
+	fi
+else
+	MSG=""
+	CHECK="$(batctl gwl -H|grep -v "gateways in range"|wc -l)"
+fi
+
+UP=$(($UT / 60))
+M=$(($UP % $MINUTES))
+
+HUP_NEEDED=0
+if [ "$CHECK" -gt 0 ] || [ "$DISABLED" = '1' ]; then
+	echo "node is online"
+	LOOP=1
+	# check status for all physical devices
+	for HOSTAPD in $(ls /var/run/hostapd-phy*); do
+		ONLINE_SSID="$(echo $ONLINE_SSIDs | awk -F '~' -v l=$((LOOP*2)) '{print $l}')" 
+		LOOP=$((LOOP+1))
+		CURRENT_SSID="$(grep "^ssid=$ONLINE_SSID" $HOSTAPD | cut -d"=" -f2)"
+		if [ "$CURRENT_SSID" = "$ONLINE_SSID" ]; then
+			echo "SSID $CURRENT_SSID is correct, nothing to do"
+			break
+		fi
+		CURRENT_SSID="$(grep "^ssid=$OFFLINE_SSID" $HOSTAPD | cut -d"=" -f2)"
+		if [ "$CURRENT_SSID" = "$OFFLINE_SSID" ]; then
+			# set online
+			logger -s -t "gluon-ssid-changer" -p 5 $MSG"SSID is $CURRENT_SSID, change to $ONLINE_SSID"
+			sed -i "s~^ssid=$CURRENT_SSID~ssid=$ONLINE_SSID~" $HOSTAPD
+			# HUP here would be to early for dualband devices
+			HUP_NEEDED=1
+		else
+			logger -s -t "gluon-ssid-changer" -p 5 "could not set to online state: did neither find SSID '$ONLINE_SSID' nor '$OFFLINE_SSID'. Please reboot"
+		fi
+	done
+elif [ "$CHECK" -eq 0 ]; then
+	echo "node is considered offline"
+	if [ $UP -lt $FIRST ] || [ $M -eq 0 ]; then
+		# set SSID offline, only if uptime is less than FIRST or exactly a multiplicative of switch_timeframe
+		if [ $UP -lt $FIRST ]; then 
+			T=$FIRST
+		else
+			T=$MINUTES
+		fi
+		#echo minute $M, check if $OFF_COUNT is more than half of $T 
+		if [ $OFF_COUNT -ge $(($T / 2)) ]; then
+			# node was offline more times than half of switch_timeframe (or than $FIRST)
+			LOOP=1
+			for HOSTAPD in $(ls /var/run/hostapd-phy*); do
+				ONLINE_SSID="$(echo $ONLINE_SSIDs | awk -F '~' -v l=$((LOOP*2)) '{print $l}')" 
+				LOOP=$((LOOP+1))
+				CURRENT_SSID="$(grep "^ssid=$OFFLINE_SSID" $HOSTAPD | cut -d"=" -f2)"
+				if [ "$CURRENT_SSID" = "$OFFLINE_SSID" ]; then
+					echo "SSID $CURRENT_SSID is correct, nothing to do"
+					break
+				fi
+				CURRENT_SSID="$(grep "^ssid=$ONLINE_SSID" $HOSTAPD | cut -d"=" -f2)"
+				if [ "$CURRENT_SSID" = "$ONLINE_SSID" ]; then
+					# set offline
+					logger -s -t "gluon-ssid-changer" -p 5 $MSG"$OFF_COUNT times offline, SSID is $CURRENT_SSID, change to $OFFLINE_SSID"
+					sed -i "s~^ssid=$ONLINE_SSID~ssid=$OFFLINE_SSID~" $HOSTAPD
+					HUP_NEEDED=1
+				else
+					logger -s -t "gluon-ssid-changer" -p 5 "could not set to offline state: did neither find SSID '$ONLINE_SSID' nor '$OFFLINE_SSID'. Please reboot"
+				fi
+			done
+		fi
+		#else echo minute $M, just count $OFF_COUNT
+	fi
+	echo "$(($OFF_COUNT + 1))">$TMP
+fi
+
+if [ $HUP_NEEDED = 1 ]; then
+	# send HUP to all hostapd to load the new SSID
+	killall -HUP hostapd
+	HUP_NEEDED=0
+	echo "HUP!"
+fi
+
+if [ $M -eq 0 ]; then
+	# set counter to 0 if the timeframe is over
+	echo "0">$TMP
+fi