Nick ten Cate's Blog

echo "#!/bin/sh \n killall -TERM nas \n nas -P /tmp/nas.wl0lan.pid -H 34954 -l br0 -i eth1 -A -m 64 -r RADIUS_KEY -s SSID_USED -w 4 -g 3600 -h RADIUS_SERVER_IP -p RADIUS_SERVER_PORT" >> /tmp/root/nasReset.sh
echo ' * 5 * * * root /tmp/root/nasReset.sh' >> /tmp/crontab
startservice cron

DD-WRT v24 pre-SP2 SNMP Clients on eth1(wl0) and wl0.1

So for a pet project I recently had to record and graph how many clients were on any SSID at one time, accross all 30+ dd-wrt enabled routers. It seems the built in SNMP client does not have this capability So naturally, I had to figure out my own. Here’s how I did it.

First, host this script on a webserver that can be reached by all intended routers. For this guide, it will be placed at http://192.168.1.2/ddwrtSnmpScript.txt

#!/bin/sh

place=".1.3.6.1.4.1.2021.254"

refresh() {

  # Calc total clients Eth1
  wlId="eth1"
  totalClientsEth1=0
  for mac in $(wl -i $wlId assoclist | cut -d" " -f2)
  do
   let totalClientsEth1=$totalClientsEth1+1
  done

  # Calc total clients Wl0.1
  wlId="wl0.1"
  totalClientsWl01=0

  for mac in $(wl -i $wlId assoclist | cut -d" " -f2)
  do
   let totalClientsWl01=$totalClientsWl01+1
  done

  let totalClients=$totalClientsWl01+$totalClientsEth1

  eval getnext_1361412021254="$place.3.54.1.3.32.1.27.1"

  # DESCRIPTIONS
  # Total Clients
  eval value_136141202125435413321271="Total_Clients_on_AP"
  eval type_136141202125435413321271="string"

  # Total Clients eth1
  eval getnext_136141202125435413321271="$place.3.54.1.3.32.1.27.2"
  eval value_136141202125435413321272="Total_Clients_using_eth1_on_AP"
  eval type_136141202125435413321272="string"

  # Total Clients wl0.1
  eval getnext_136141202125435413321272="$place.3.54.1.3.32.1.27.3"
  eval value_136141202125435413321273="Total_Clients_using_wl0.1_on_AP"
  eval type_136141202125435413321273="string"

  eval getnext_136141202125435413321273="$place.3.54.1.3.32.1.28.1"

  # VALUES

  # Total Clients
  eval value_136141202125435413321281=$totalClients
  eval type_136141202125435413321281="integer"

  # Total Clients eth1
  eval getnext_136141202125435413321281="$place.3.54.1.3.32.1.28.2"
  eval value_136141202125435413321282=$totalClientsEth1
  eval type_136141202125435413321282="integer"

  # Total Clients wl0.1
  eval getnext_136141202125435413321282="$place.3.54.1.3.32.1.28.3"
  eval value_136141202125435413321283=$totalClientsWl01
  eval type_136141202125435413321283="integer"

  eval getnext_13614120212543541332128${lastid}="NONE"
}

LASTREFRESH=0

while read CMD
do
  case "$CMD" in
    PING)
      echo PONG
      continue
      ;;
    getnext)
      read REQ
      let REFRESH=$(date +%s)-$LASTREFRESH
      if test $REFRESH -gt 30
      then
        LASTREFRESH=$(date +%s)
        refresh
      fi

      oid=$(echo $REQ | tr -d .)
      eval ret=\$getnext_${oid}
      if test "x$ret" = "xNONE"
      then
        echo NONE
        continue
      fi
      ;;
    *)
      read REQ
      if test "x$REQ" = "x$place"
      then
        echo NONE
        continue
      else
        ret=$REQ
      fi
      ;;
  esac

  oid=$(echo $ret | tr -d .)
  if eval test "x\$type_${oid}" != "x"
  then
    echo $ret
    eval echo "\$type_${oid}"
    eval echo "\$value_${oid}"
  else
    echo NONE
  fi

done

Next, go to your DD-WRT “Services” -> “Services” and enable SNMP (http://192.168.1.1/Services.asp).

Then go to your DD-WRT “Administration” -> “Commands” (http://192.168.1.1/Diagnostics.asp) and enter the following into your startup script.

wget http://192.168.1.2/ddwrtSnmpScript.txt -O /tmp/root/snmp.sh
chmod +x /tmp/root/snmp.sh
echo "pass_persist .1.3.6.1.4.1.2021.254 /tmp/root/snmp.sh" >> /var/snmp/snmpd.conf
killall -TERM snmpd
snmpd -c /var/snmp/snmpd.conf

Restart your router…

Then viola!

root@MONITOR-1:~# snmpwalk -v2c -c public 192.168.1.1 1.3.6.1.4.1.2021.254
UCD-SNMP-MIB::ucdavis.254.3.54.1.3.32.1.27.1 = STRING: "Total_Clients_on_AP"
UCD-SNMP-MIB::ucdavis.254.3.54.1.3.32.1.27.2 = STRING: "Total_Clients_using_eth1_on_AP"
UCD-SNMP-MIB::ucdavis.254.3.54.1.3.32.1.27.3 = STRING: "Total_Clients_using_wl0.1_on_AP"
UCD-SNMP-MIB::ucdavis.254.3.54.1.3.32.1.28.1 = INTEGER: 73
UCD-SNMP-MIB::ucdavis.254.3.54.1.3.32.1.28.2 = INTEGER: 64
UCD-SNMP-MIB::ucdavis.254.3.54.1.3.32.1.28.3 = INTEGER: 9

Tags: dd-wrt, router, snmp