From c9525b9b2261a9e9b5c15525b1f3b485ec72a943 Mon Sep 17 00:00:00 2001
From: Manuel Munz <freifunk@somakoma.de>
Date: Sat, 19 Jan 2013 20:32:06 +0000
Subject: [PATCH] contrib/freifunk-gwcheck: check which interface is wan when
 we get the upstream dns servers, add priorities to logger calls, check for
 dyngw_plain plugin before checking if script already runs, add
 license/copyright

---
 .../files/usr/sbin/ff_olsr_test_gw.sh         | 64 ++++++++-----------
 1 file changed, 27 insertions(+), 37 deletions(-)

diff --git a/contrib/package/freifunk-gwcheck/files/usr/sbin/ff_olsr_test_gw.sh b/contrib/package/freifunk-gwcheck/files/usr/sbin/ff_olsr_test_gw.sh
index f53dd02d77..a85ead3ce6 100755
--- a/contrib/package/freifunk-gwcheck/files/usr/sbin/ff_olsr_test_gw.sh
+++ b/contrib/package/freifunk-gwcheck/files/usr/sbin/ff_olsr_test_gw.sh
@@ -1,28 +1,28 @@
 #!/bin/sh
+# Copyright 2013 Manuel Munz <freifunk at somakoma dot de>
+# Licensed under the GNU General Public License (GPL) v3
+# This script monitors the local internet gateway
 
 . /lib/functions/network.sh
 
-#Exit if this script is already running
-pid="$(pidof ff_olsr_test_gw.sh)"
-if [ ${#pid} -gt 5 ]; then
-	logger -t gwcheck "Gateway check script is already running, exit now"
-	exit 1
-fi
-
-#check if dyngw_plain is installed and enabled, else exit
-dyngwplainlib=`uci show olsrd |grep dyn_gw_plain |awk {' FS="."; print $1"."$2 '}`
-if [ -n "$dyngwplainlib" ]; then
-	if [ "$(uci -q get $dyngwplainlib.ignore)" == 1 ]; then
+# exit if dyngw_plain is not installed or enabled
+dgwlib=`uci show olsrd |grep dyn_gw_plain |awk {' FS="."; print $1"."$2 '}`
+if [ -n "$dgwlib" ]; then
+	if [ "$(uci -q get $dgwlib.ignore)" == 1 ]; then
 		exit 1
 	fi
 else
-	echo "dyngw_plain not found in olsrd config, exit"
 	exit 1
 fi
 
+#Exit if this script is already running
+pid="$(pidof ff_olsr_test_gw.sh)"
+if [ ${#pid} -gt 5 ]; then
+	logger -p debug -t gwcheck "Gateway check script is already running, exit now"
+	exit 1
+fi
 
-# check if we have a defaultroute with metric=0 in one of these tables: main table and gw-check table.
-# If not exit here.
+# exit if there is no defaultroute with metric=0 in main or gw-check table.
 defroutemain="$(ip r s |grep default |grep -v metric)"
 defroutegwcheck="$(ip r s t gw-check |grep default |grep -v metric)"
 if [ -z "$defroutegwcheck" -a -z "$defroutemain" ]; then
@@ -56,7 +56,7 @@ check_internet() {
 			echo 0
 			break
 		else
-			logger -t gw-check "Could not get test file from http://$t/conntest.html"
+			logger -p debug -t gw-check "Could not fetch http://$t/conntest.html"
 		fi
 	done
 }
@@ -66,54 +66,45 @@ resolve() {
 }
 
 get_dnsservers() {
-	# this gets all dns servers for the wan interface. If ubus is not present (like on older
-	# openwrt versions before Attitude fallback to get these from /var/state/network.
+	# this gets all dns servers for the interface which has the default route
 
 	dns=""
-	if [ -x /bin/ubus ]; then
-		network_get_dnsserver dns wan
-	else
+	if [ ! -x /bin/ubus ]; then
+		# ubus not present (versions before Attitude): fallback to get these from /var/state/network.
+		# We always assume that wan is the default route interface here
 		dns="$(grep network.wan.resolv_dns /var/state/network | cut -d "=" -f 2)"
+	else
+		network_find_wan wan
+		network_get_dnsserver dns $wan
 	fi
 }
 
 iw=$(check_internet)
 
-
 if [ "$iw" == 0 ]; then
-	# check if we have a seperate routing table for our tests.
-	# If yes, move defaultroute to normal table and delete table gw-check
-	# Also delete ip rules to use table gw-check for our testhosts and wan dns servers
-	
+	# Internet available again, restore default route and remove ip rules
 	if [ -n "$defroutegwcheck" ]; then
 		ip r a $defroutegwcheck
 		ip r d $defroutegwcheck t gw-check
-		ip ru del fwmark 0x2 lookup gw-check
 		for host in $testserver; do
 			ips="$(resolve $host)"
 			for ip in $ips; do
 				[ -n "$(ip ru s | grep "to $ip lookup gw-check")" ] && ip rule del to $ip table gw-check
 			done
 		done
-
 		get_dnsservers
 		for d in $dns; do
 			[ -n "$(ip ru s | grep "to $d lookup gw-check")" ] && ip rule del to $d table gw-check
 		done
-
-		#ip r d default via 127.0.0.1 metric 100000
-		logger -t gw-check "Internet is available again, restoring default route ( $defroutegwcheck)"
+		logger -p err -t gw-check "Internet is available again, default route restored ( $defroutegwcheck)"
 	fi
 
 else
-	# Check failed. If we have a defaultroute with metric=0 and it is already in table gw-check then do nothing.
-	# If there is a defaultroute with metric=0 then remove it from the main routing table and add to table gw-check.
-	# Also setup ip rules to use table gw-check for our testhosts and wan dns servers
-
+	# Check failed. Move default route to table gw-check and setup ip rules.
 	if [ -z "$(ip ru s | grep gw-check)" -a -n "$defroutemain" ]; then
-		ip rule add fwmark 0x2 lookup gw-check
 		ip r a $defroutemain table gw-check
 		ip r d $defroutemain
+		logger -p err -t gw-check "Internet is not available, default route deactivated ( $defroutemain)"
 	fi
 	for host in $testserver; do
 		ips="$(resolve $host)"
@@ -125,6 +116,5 @@ else
 	for d in $dns; do
 		[ -z "$(ip ru s | grep "to $d lookup gw-check")" ] && ip rule add to $d table gw-check
 	done
-	#ip r a default via 127.0.0.1 metric 100000
-	logger -t gw-check "Internet is not available, deactivating the default route ( $defroutemain)"
+	logger -p err -t gw-check "Check your internet connection!"
 fi
-- 
2.30.2