We can use this script to create/delete a private bridge,
and launch a dhcp server on the bridge by dnsmasq,
setup forware rule of iptable, then guest can access public network.
# ./set_private_br.sh vbr0 192.168.33
add new private bridge: vbr0
# brctl show
bridge name bridge id STP enabled interfaces
vbr0 8000.000000000000 yes
# ifconfig vbr0
vbr0 Link encap:Ethernet HWaddr 82:0f:f5:8f:92:47
inet addr:192.168.33.1 Bcast:192.168.33.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:1979 (1.9 KB)
# ps aux |grep dnsmasq
nobody .. dnsmasq --strict-order --bind-interfaces --listen-address
192.168.33.1 \
--dhcp-range 192.168.33.1,192.168.33.254
Signed-off-by: Amos Kong <[email protected]>
---
tools/kvm/util/set_private_br.sh | 51 ++++++++++++++++++++++++++++++++++++++
1 files changed, 51 insertions(+), 0 deletions(-)
create mode 100755 tools/kvm/util/set_private_br.sh
diff --git a/tools/kvm/util/set_private_br.sh b/tools/kvm/util/set_private_br.sh
new file mode 100755
index 0000000..49867dd
--- /dev/null
+++ b/tools/kvm/util/set_private_br.sh
@@ -0,0 +1,51 @@
+#!/bin/bash
+#
+# Author: Amos Kong <[email protected]>
+# Date: Apr 14, 2011
+# Description: this script is used to create/delete a private bridge,
+# launch a dhcp server on the bridge by dnsmasq.
+#
+# @ ./set_private_br.sh $bridge_name $subnet_prefix
+# @ ./set_private_br.sh vbr0 192.168.33
+
+brname='vbr0'
+subnet='192.168.33'
+
+add_br()
+{
+ echo "add new private bridge: $brname"
+ /usr/sbin/brctl addbr $brname
+ echo 1 > /proc/sys/net/ipv6/conf/$brname/disable_ipv6
+ echo 1 > /proc/sys/net/ipv4/ip_forward
+ /usr/sbin/brctl stp $brname on
+ /usr/sbin/brctl setfd $brname 0
+ ifconfig $brname $subnet.1
+ ifconfig $brname up
+ # Add forward rule, then guest can access public network
+ iptables -t nat -A POSTROUTING -s $subnet.254/24 ! -d $subnet.254/24 -j
MASQUERADE
+ /etc/init.d/dnsmasq stop
+ /etc/init.d/tftpd-hpa stop 2>/dev/null
+ dnsmasq --strict-order --bind-interfaces --listen-address $subnet.1
--dhcp-range $subnet.1,$subnet.254 $tftp_cmd
+}
+
+del_br()
+{
+ echo "cleanup bridge setup"
+ kill -9 `pgrep dnsmasq|tail -1`
+ ifconfig $brname down
+ /usr/sbin/brctl delbr $brname
+ iptables -t nat -D POSTROUTING -s $subnet.254/24 ! -d $subnet.254/24 -j
MASQUERADE
+}
+
+
+if [ $# = 0 ]; then
+ del_br 2>/dev/null
+ exit
+fi
+if [ $# > 1 ]; then
+ brname="$1"
+fi
+if [ $# = 2 ]; then
+ subnet="$2"
+fi
+add_br
--
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