Cickd 註解

今天要來記錄一下clickd的語法
因為太難了...要做個紀錄
以下是我們可以看到clickd中的code

#!/bin/sh 

# Copyright (c) 2006, Roberto Riggio
#
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without 
# modification, are permitted provided that the following conditions    
# are met:
# 
#   - Redistributions of source code must retain the above copyright 
#     notice, this list of conditions and the following disclaimer.
#   - Redistributions in binary form must reproduce the above copyright 
#     notice, this list of conditions and the following disclaimer in 
#     the documentation and/or other materials provided with the 
#     distribution.
#   - Neither the name of the CREATE-NET nor the names of its 
#     contributors may be used to endorse or promote products derived 
#     from this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:./
DAEMON=click => 可執行檔
HELPER=click_config =>由click_config產生腳本
NAME=clickd

MODE="11g"
CHANNEL="2412"
DEV="moni0"

PROFILE="bulk"
LS="fcfs"
METRIC="wcett" => 有hop-count與wcett，這是route機制
RC="minstrel" => 有static與minstrel，這是Rate Control機制

CLICK_FILE=/var/run/$NAME.click
PID_FILE=/var/run/$NAME.pid
LOG_FILE=/var/log/$NAME.log 

test -x "$(which $DAEMON)" || exit 0
test -x "$(which $HELPER)" || exit 0

case "$1" in
  start)

 echo "Starting $NAME"

 if which wlanconfig > /dev/null 2>&1; then  => > /dev/null 2>&1表示說不Print在螢幕上
  PHY="wifi0"
  WLANCONFIG=$(which wlanconfig)
  [ ! -f "$WLANCONFIG" ] && {
   echo "Couldn't find wlanconfig";
   exit 1; 
  }
  $WLANCONFIG $DEV destroy 2> /dev/null
  $WLANCONFIG $DEV create wlandev $PHY wlanmode monitor > /dev/null 2>&1 || {
   echo "Couldn't create monitor device on $PHY";
   exit 1; 
  }
  echo '803' >  /proc/sys/net/$DEV/dev_type
  /sbin/iwpriv $DEV mode $MODE
 elif which iw > /dev/null 2>&1; then
  PHY="phy0"
  IW=$(which iw)
  [ ! -f "$IW" ] && {
   echo "Couldn't find iw";
   exit 1; 
  }
  $IW dev $DEV del > /dev/null 2>&1
  $IW phy $PHY interface add $DEV type monitor > /dev/null 2>&1 || {
   echo "Couldn't create monitor device on $PHY";
   exit 1; 
  }
 else
  echo "Couldn't find neither iw or wlanconfig";
  exit 1
 fi

 /sbin/iwconfig $DEV channel ${CHANNEL}M
 /sbin/ifconfig $DEV mtu 1900
 /sbin/ifconfig $DEV txqueuelen 5
 /sbin/ifconfig $DEV up
 /sbin/modprobe tun > /dev/null 2>&1 =>載入Module (包製多NIC)

 # extract the bottom three octects to use as IP =>查網卡卡號，可直接設SUFFIX成0.0.0.1
 MAC=$(/sbin/ifconfig $DEV 2>&1 | sed -n 's/^.*HWaddr \([0-9A-Za-z\-]*\).*/\1/p' | sed -e 's/\-/:/g' | cut -c1-17)
 HI=$(echo $MAC | sed -n 's/.*:.*:.*:\([0-9A-Za-z:]*\):.*:.*.*/\1/p')
 MID=$(echo $MAC | sed -n 's/.*:.*:.*:.*:\([0-9A-Za-z:]*\):.*.*/\1/p')
 LOW=$(echo $MAC | sed -n 's/.*:.*:.*:.*:.*:\([0-9A-Za-z:]*\).*/\1/p')
 SUFFIX=$((0x$HI)).$((0x$MID)).$((0x$LOW))

 XR_IFNAME="wing-mesh"
 XR_IP="6.$SUFFIX"
 XR_NM="255.0.0.0"
 XR_PERIOD="36000"
 XR_TAU="360000"

 $HELPER -p $PROFILE -r $RC -s $LS -l $METRIC -m $MODE -c $CHANNEL -n $DEV -a $MAC -d \
  | sed -e "s/__XR_IFNAME__/$XR_IFNAME/g" \
  | sed -e "s/__XR_IP__/$XR_IP/g" \
  | sed -e "s/__XR_NM__/$XR_NM/g" \
  | sed -e "s/__XR_PERIOD__/$XR_PERIOD/g" \
  | sed -e "s/__XR_TAU__/$XR_TAU/g" > $CLICK_FILE

 $DAEMON $CLICK_FILE > $LOG_FILE 2>&1 &

 sleep 2
 if ! pidof $DAEMON > /dev/null 2>&1; then
  echo "Unable to start click. Check log for more information."
  exit 1
 fi

 pidof $DAEMON > $PID_FILE

 ;;
  stop)
 echo "Stopping $NAME"

 if which wlanconfig > /dev/null 2>&1; then
  WLANCONFIG=$(which wlanconfig)
  [ ! -f "$WLANCONFIG" ] && {
   echo "Couldn't find wlanconfig";
   exit 1; 
  }
  $WLANCONFIG $DEV destroy > /dev/null 2>&1
 elif which iw > /dev/null 2>&1; then
  IW=$(which iw)
  [ ! -f "$IW" ] && {
   echo "Couldn't find iw";
   exit 1; 
  }
  $IW dev $DEV del > /dev/null 2>&1
 else
  exit 1
 fi
 [ -f $PID_FILE ] && {
  kill -9 $(cat $PID_FILE)
  [ -f $PID_FILE ] && rm $PID_FILE
 }
 [ -f $CLICK_FILE ] && rm $CLICK_FILE
 [ -f $LOG_FILE ] && rm $LOG_FILE
 ;;
  restart|force-reload)
 $0 stop
 sleep 1
 $0 start
 ;;
  *)
 echo "Usage: $NAME {start|stop|restart}" >&2
 exit 1
 ;;
esac

exit 0