--- badi/public_scripts/switchgate/switchgate	2009/04/24 00:12:49	1.1
+++ badi/public_scripts/switchgate/switchgate	2010/01/09 04:25:42	1.5
@@ -16,6 +16,10 @@ CONFIG_PATH="/etc/switchgate"
 # the dhclient-exit-hook helper program
 DHCP_TMP_DIR=/tmp/switchgate
 
+# eMail address to send alert messages, if not operating on the
+# standard default gateway
+ALERT_EMAIL="adi@ente.limmat.ch"
+
 # Host set to ping. A file containing IP addresses, each on a single line.
 # Do not include any local hosts, list only hosts located behind your gateways.
 HOSTSET_FILE="$CONFIG_PATH/hostset"
@@ -24,7 +28,7 @@ HOSTSET_FILE="$CONFIG_PATH/hostset"
 GATEWAYS_FILE="$CONFIG_PATH/gateways"
 
 # path to fping
-PING=/usr/sbin/fping
+PING=/usr/bin/fping
 
 # answer of fping to reachable hosts
 ALIVE_ANSWER="is alive"
@@ -32,7 +36,7 @@ ALIVE_ANSWER="is alive"
 # set to an empty string to avoid debug output
 # to "low" for a few output and to anything else
 # for verbose output
-DEBUG=
+DEBUG=low
 
 
 # -------- Do not edit below this line --------
@@ -43,6 +47,61 @@ PINGARGS="-A -p25 -t100"
 ## Function declarations
 #
 
+# parse commandline switches
+function parse_commandline {
+	
+	# check rest
+	while [ "$#" -gt 0 ]; do
+
+	   case "$1" in
+
+	   -d|--debug)
+   		# debug switch (another hidden feature)
+		shift
+		if [ "$1" != "low" ]; then
+			DEBUG="choke"
+			echo "Debug mode on."
+		else
+			#echo "Info mode on."
+			DEBUG="low"
+			shift
+		fi
+		;;
+
+	   -C)
+   		# Parse writeable dir request (hidden feature)
+		echo "$DHCP_TMP_DIR"
+		exit 0
+		;;
+
+	   -q|--query)
+		# Parse query for current gw  (yet another hidden feature)
+		shift
+		parse_commandline "$@"
+		getcurrentgw
+		echo "$CURRENTGW"
+		exit 0
+		;;
+
+	   -s|--set)
+   		# Set gateway to number n (yet another hidden feature)
+		shift
+		set_to_gw="$1"
+		shift
+		parse_commandline "$@"
+		set_gw
+		exit 0
+		;;
+
+	   *)
+		echo "Invalid argument \"$1\"."
+		exit 1
+		;;
+
+	   esac
+	done
+}
+
 # Read gateways from file
 function readgwlist {
 	if [ -f "$GATEWAYS_FILE" ]; then
@@ -81,7 +140,7 @@ function readgwlist {
 			unset alldhcpgates
 		done
 	fi
-	
+
 	if [ "$number_of_gws" -eq 0 ]; then
 		echo "No gateways configured. Please edit $GATEWAYS_FILE."
 		exit 1
@@ -117,7 +176,7 @@ function checkconnection {
    if [ -n "$DEBUG" ]; then
       if [ -n "$UP" ]; then
          echo "The connection is up."
-      else 
+      else
          echo "The connection is down."
       fi
    fi
@@ -130,13 +189,14 @@ function checkgw {
          echo "$NEWGW is reachable."
       fi
     else
-      if [ -n "$DEBUG" ]; then 
+      if [ -n "$DEBUG" ]; then
           echo "$NEWGW is not reachable."
       fi
       NEWGW=""
    fi
 }
 
+# Get the current default gateway (or set it, if there was none set) 
 function getcurrentgw {
    iproute_default_gw_txt="$(ip route show scope global)"
    if [ `echo $iproute_default_gw_txt | grep -c default` -gt 1 ]; then
@@ -144,18 +204,21 @@ function getcurrentgw {
       exit 1
    else
       iproute_default_gw_txt="$(echo "$iproute_default_gw_txt" | grep "default via")"
-   fi  
+   fi
    if [ -z "$iproute_default_gw_txt" ]; then
       # no default gateway currently set, set to the highest index, to land on GW0
       CURRENTGW_ID=0
       CURRENTGW=${GW[$CURRENTGW_ID]}
-      CURRENTGW_DEV="unknown"
       echo "No default gateway currently set. Setting it now to $CURRENTGW."
       ip route add default via $CURRENTGW
+      if [ $? -eq 2 ]; then
+	echo "Not able to switch default gateway. Is your interface up?"
+	exit 1
+      fi
    else
-      CURRENTGW=`echo $iproute_default_gw_txt | sed "s/^default via \(\([0-9]\+\.\?\)\{4\}\).*\$/\1/"` 
-      CURRENTGW_DEV=`echo $iproute_default_gw_txt | sed "s/^default via .* dev \(eth[0-9]\+\).*\$/\1/"` 
+      CURRENTGW=`echo $iproute_default_gw_txt | sed "s/^default via \(\([0-9]\+\.\?\)\{4\}\).*\$/\1/"`
    fi
+   CURRENTGW_DEV=`echo $iproute_default_gw_txt | sed "s/^default via .* dev \(eth[0-9]\+\).*\$/\1/"`
 
    # get index of current gateway
    index=-1
@@ -197,7 +260,7 @@ function getnextgw {
 function getnewgw {
    getnextgw
    # Check wheter all gateways are already tested and failed
-   if [ "$NEWGW_ID" -eq "$CURRENTGW_ID" ]; then
+   if [[ "$NEWGW_ID" -eq "$CURRENTGW_ID" &&  -z $set_to_gw ]]; then
       if [ -n "$DEBUG" ]; then
          echo "All gateways tried."
       fi
@@ -223,13 +286,40 @@ function getnewgw {
    fi
 }
 
+# Switch the gateway to a desired gateway
+function set_gw {
+
+   # get name of gateway
+   if [[ ! "$set_to_gw" =~ ^[0-9]{1,}$ ]]; then
+	echo "Only positive numbers allowed. Invalid value \"$set_to_gw\"."
+	exit 1   
+   fi
+   
+   NEWGW=${GW[$set_to_gw]}
+   if [ -z "$NEWGW" ]; then
+      echo "The gateway number $set_to_gw is not in the list of available gateways."
+      echo "Valid gateways are:"
+      for ((gw=0; gw<${#GW[*]}; gw++)); do
+      	  echo -e "\t$gw (${GW[$gw]})"
+      done 
+      exit 1
+   fi
+   if [ -n "$DEBUG" -a "$DEBUG" != "low" ]; then
+      echo "Default gateway desired: $NEWGW ($set_to_gw)"
+   fi
+   
+   getcurrentgw
+   NEWGW_ID=$[ $set_to_gw - 1 ]
+   switchgw
+}
+
 function switchgw {
    getnewgw
    if [ -n "$NEWGW" ]; then
       if [ "$DEBUG" = "low" ]; then
          echo -n "Switching default gateway now to $NEWGW ($NEWGW_ID)..."
-      fi 
-      
+      fi
+
       iproute_msg="$(ip route change default via $NEWGW 2>&1 )"
       iproute_exit=$?
 
@@ -237,7 +327,7 @@ function switchgw {
       sleep 1
       GARBAGE=`$PING -q -c 5 -t100 -p50 -A -f $HOSTSET_FILE 2> /dev/null`
       sleep 1
-      
+
       if [ "$DEBUG" = "low" ]; then
          echo "done."
       fi
@@ -270,33 +360,18 @@ function switchgw {
 ## MAIN
 #
 
-# Parse writeable dir request (hidden feature)
-if [ "$1" = "-C" ]; then
-	echo "$DHCP_TMP_DIR"
-	exit 0
-fi
 
-# Parse debug switch (another hidden feature)
-if [ "$1" = "-d" ]; then
-	if [ "$2" != "low" ]; then
-		echo "Debug mode on."
-		DEBUG="choke"
-	else
-		#echo "Info mode on."
-		DEBUG="low"
-	fi 
+# Check fping existence
+if [ ! -x "$PING" ]; then
+	echo -e "Error: Ping program not executable or not found at $PING.\nPlease configure the full path in $0."
+	exit 1
 fi
 
 # Get all gateways, we can forward traffic
 readgwlist
 
-# Parse query for current gw  (yet another hidden feature)
-if [ "$1" = "-q" ]; then
-	DEBUG=
-	getcurrentgw
-	echo "$CURRENTGW"
-	exit 0
-fi
+# parse commandline switches
+parse_commandline "$@"
 
 # get current gw
 getcurrentgw
@@ -317,13 +392,13 @@ if [ -z "$UP" ]; then
    checkgw
    if [ -z "$NEWGW" ]; then
       echo "Gateway $CURRENTGW is down."
-   else 
+   else
       echo "No connection through gateway $CURRENTGW." 
    fi
-  
+
    NEWGW_ID=$CURRENTGW_ID
    switchgw
-   
+
 else
    # If the current gateway is not the standard default gateway, try if the connection 
    # through the standard default gateway is back
@@ -341,6 +416,23 @@ else
    fi
 fi
 
+# send an eMail if the connection is down or limited
+if [ -z "$UP" ]; then
+	EMAIL_BODY="Switchgate on $(hostname -f) reports: No connection!\n\nTime:\t\t$(date)\nGateway:\t$CURRENTGW ($CURRENTGW_ID)"
+	EMAIL_SUBJECT="Attention: $(hostname -f) has no connection!"
+	echo -e "$EMAIL_BODY" | mail -s "$EMAIL_SUBJECT" "$ALERT_EMAIL"
+	if [[ -n "$DEBUG" && "$DEBUG" != "low" ]]; then
+		echo "Alert message sent to $ALERT_EMAIL."
+	fi
+elif [ "$CURRENTGW_ID" != 0 ]; then
+	EMAIL_BODY="Switchgate on $(hostname -f) reports: Not operating on standard default gateway!\n\nTime:\t\t$(date)\nGateway:\t$CURRENTGW ($CURRENTGW_ID)"
+	EMAIL_SUBJECT="Attention: $(hostname -f) not operating on standard default gateway!"
+	echo -e "$EMAIL_BODY" | mail -s "$EMAIL_SUBJECT" "$ALERT_EMAIL"
+	if [[ -n "$DEBUG" && "$DEBUG" != "low" ]]; then
+		echo "Alert message sent to $ALERT_EMAIL."
+	fi
+fi
+
 if [ "$DEBUG" = "low" ]; then
    echo
    echo "Default Gateway: $CURRENTGW ($CURRENTGW_ID)"