contrib/package/freifunk-gwcheck/files/usr/sbin/ff_olsr_test_gw.sh

   1 #!/bin/sh
   2 # Copyright 2013 Manuel Munz <freifunk at somakoma dot de>
   3 # Licensed under the GNU General Public License (GPL) v3
   4 # This script monitors the local internet gateway
   5
   6 . /lib/functions/network.sh
   7
   8 #Exit if this script is already running
   9 pid="$(pidof ff_olsr_test_gw.sh)"
  10 if [ ${#pid} -gt 5 ]; then
  11         logger -t gwcheck "Gateway check script is already running, exit now"
  12         exit 1
  13 fi
  14
  15 #check if dyngw_plain is installed and enabled, else exit
  16 dyngwplainlib=`uci show olsrd |grep dyn_gw_plain |awk {' FS="."; print $1"."$2 '}`
  17 if [ -n "$dyngwplainlib" ]; then
  18         if [ "$(uci -q get $dyngwplainlib.ignore)" == 1 ]; then
  19                 exit 1
  20         fi
  21 else
  22         exit 1
  23 fi
  24
  25 #Exit if this script is already running
  26 pid="$(pidof ff_olsr_test_gw.sh)"
  27 if [ ${#pid} -gt 5 ]; then
  28         logger -p debug -t gwcheck "Gateway check script is already running, exit now"
  29         exit 1
  30 fi
  31
  32 # exit if there is no defaultroute with metric=0 in main or gw-check table.
  33 defroutemain="$(ip r s |grep default |grep -v metric)"
  34 defroutegwcheck="$(ip r s t gw-check |grep default |grep -v metric)"
  35 if [ -z "$defroutegwcheck" -a -z "$defroutemain" ]; then
  36         exit 1
  37 fi
  38
  39 # get and shuffle list of testservers
  40 testserver="$(uci -q get freifunk-gwcheck.hosts.host)"
  41 [ -z "$testserver" ] && echo "No testservers found, exit" && exit
  42
  43 testserver="$(for t in $testserver; do echo $t; done | awk 'BEGIN {
  44         srand();
  45 }
  46 {
  47         l[NR] = $0;
  48 }
  49
  50 END {
  51         for (i = 1; i <= NR; i++) {
  52                 n = int(rand() * (NR - i + 1)) + i;
  53                 print l[n];
  54                 l[n] = l[i];
  55         }
  56 }')"
  57
  58 check_internet() {
  59         for t in $testserver; do
  60                 local test
  61                 test=$(wget -q http://$t/conntest.html -O -| grep "Internet_works")
  62                 if [ "$test" == "Internet_works" ]; then
  63                         echo 0
  64                         break
  65                 else
  66                         logger -p debug -t gw-check "Could not fetch http://$t/conntest.html"
  67                 fi
  68         done
  69 }
  70
  71 resolve() {
  72         echo "$(nslookup $1 2>/dev/null |grep 'Address' |grep -v '127.0.0.1' |awk '{ print $3 }')"
  73 }
  74
  75 get_dnsservers() {
  76         # this gets all dns servers for the wan interface. If ubus is not present (like on older
  77         # openwrt versions before Attitude fallback to get these from /var/state/network.
  78
  79         dns=""
  80         if [ -x /bin/ubus ]; then
  81                 network_get_dnsserver dns wan
  82         else
  83                 dns="$(grep network.wan.resolv_dns /var/state/network | cut -d "=" -f 2)"
  84         fi
  85 }
  86
  87 iw=$(check_internet)
  88
  89
  90 if [ "$iw" == 0 ]; then
  91         # check if we have a seperate routing table for our tests.
  92         # If yes, move defaultroute to normal table and delete table gw-check
  93         # Also delete ip rules to use table gw-check for our testhosts and wan dns servers
  94
  95         if [ -n "$defroutegwcheck" ]; then
  96                 ip r a $defroutegwcheck
  97                 ip r d $defroutegwcheck t gw-check
  98                 for host in $testserver; do
  99                         ips="$(resolve $host)"
 100                         for ip in $ips; do
 101                                 [ -n "$(ip ru s | grep "to $ip lookup gw-check")" ] && ip rule del to $ip table gw-check
 102                         done
 103                 done
 104
 105                 get_dnsservers
 106                 for d in $dns; do
 107                         [ -n "$(ip ru s | grep "to $d lookup gw-check")" ] && ip rule del to $d table gw-check
 108                 done
 109
 110                 #ip r d default via 127.0.0.1 metric 100000
 111                 logger -t gw-check "Internet is available again, restoring default route ( $defroutegwcheck)"
 112         fi
 113
 114 else
 115         # Check failed. If we have a defaultroute with metric=0 and it is already in table gw-check then do nothing.
 116         # If there is a defaultroute with metric=0 then remove it from the main routing table and add to table gw-check.
 117         # Also setup ip rules to use table gw-check for our testhosts and wan dns servers
 118
 119         if [ -z "$(ip ru s | grep gw-check)" -a -n "$defroutemain" ]; then
 120                 ip r a $defroutemain table gw-check
 121                 ip r d $defroutemain
 122         fi
 123         for host in $testserver; do
 124                 ips="$(resolve $host)"
 125                 for ip in $ips; do
 126                         [ -z "$(ip ru s | grep "to $ip lookup gw-check")" ] && ip rule add to $ip table gw-check
 127                 done
 128         done
 129         get_dnsservers
 130         for d in $dns; do
 131                 [ -z "$(ip ru s | grep "to $d lookup gw-check")" ] && ip rule add to $d table gw-check
 132         done
 133         #ip r a default via 127.0.0.1 metric 100000
 134         logger -t gw-check "Internet is not available, deactivating the default route ( $defroutemain)"
 135 fi