tools/kvm/util/set_private_br.sh

   1 #!/bin/bash
   2 #
   3 # Author: Amos Kong <kongjianjun@gmail.com>
   4 # Date: Apr 14, 2011
   5 # Description: this script is used to create/delete a private bridge,
   6 # launch a dhcp server on the bridge by dnsmasq.
   7 #
   8 # @ ./set_private_br.sh $bridge_name $subnet_prefix
   9 # @ ./set_private_br.sh vbr0 192.168.33
  10
  11 brname='vbr0'
  12 subnet='192.168.33'
  13
  14 add_br()
  15 {
  16     echo "add new private bridge: $brname"
  17     /usr/sbin/brctl addbr $brname
  18     echo 1 > /proc/sys/net/ipv6/conf/$brname/disable_ipv6
  19     echo 1 > /proc/sys/net/ipv4/ip_forward
  20     /usr/sbin/brctl stp $brname on
  21     /usr/sbin/brctl setfd $brname 0
  22     ifconfig $brname $subnet.1
  23     ifconfig $brname up
  24     # Add forward rule, then guest can access public network
  25     iptables -t nat -A POSTROUTING -s $subnet.254/24 ! -d $subnet.254/24 -j MASQUERADE
  26     /etc/init.d/dnsmasq stop
  27     /etc/init.d/tftpd-hpa stop 2>/dev/null
  28     dnsmasq --strict-order --bind-interfaces --listen-address $subnet.1 --dhcp-range $subnet.1,$subnet.254 $tftp_cmd
  29 }
  30
  31 del_br()
  32 {
  33     echo "cleanup bridge setup"
  34     kill -9 `pgrep dnsmasq|tail -1`
  35     ifconfig $brname down
  36     /usr/sbin/brctl delbr $brname
  37     iptables -t nat -D POSTROUTING -s $subnet.254/24 ! -d $subnet.254/24 -j MASQUERADE
  38 }
  39
  40
  41 if [ $# = 0 ]; then
  42     del_br 2>/dev/null
  43     exit
  44 fi
  45 if [ $# > 1 ]; then
  46     brname="$1"
  47 fi
  48 if [ $# = 2 ]; then
  49     subnet="$2"
  50 fi
  51 add_br