3 # taking this bridge-initialization code out of lbuild-initvm.sh
4 # so we can use it on our libvirt/lxc local infra
5 # there's something very similar in
6 # tests/system/template-qemu/qemu-bridge-init
7 # that the current code was actually based on, but
8 # nobody was ever bold enough to reconcile these two
11 DEFAULT_PUBLIC_BRIDGE=br0
13 ##############################
14 # use /proc/net/dev instead of a hard-wired list
15 function gather_interfaces () {
17 for line in file("/proc/net/dev"):
18 if ':' not in line: continue
19 ifname=line.replace(" ","").split(":")[0]
20 if ifname.find("lo")==0: continue
21 if ifname.find("br")==0: continue
22 if ifname.find("virbr")==0: continue
23 if ifname.find("veth")==0: continue
24 if ifname.find("tap")==0: continue
29 function discover_interface () {
30 for ifname in $(gather_interfaces); do
31 ip link show $ifname | grep -qi 'state UP' && { echo $ifname; return; }
33 # still not found ? that's bad
37 ##############################
38 function check_yum_installed () {
40 rpm -q $package >& /dev/null || yum -y install $package
44 function check_yumgroup_installed () {
46 yum grouplist "$group" | grep -q Installed || { yum -y groupinstall "$group" ; }
49 #################### bridge initialization
50 function create_bridge_if_needed() {
52 # do not turn on verbosity
55 public_bridge=$1; shift
57 # already created ? - we're done
58 ip addr show $public_bridge >& /dev/null && {
59 echo "Bridge already set up - skipping create_bridge_if_needed"
63 # find out the physical interface to bridge onto
64 if_lan=$(discover_interface)
66 ip addr show $if_lan &>/dev/null || {
67 echo "Cannot use interface $if_lan - exiting"
71 #################### bride initialization
72 check_yum_installed bridge-utils
74 echo "========== $COMMAND: entering create_bridge - beg"
79 echo "========== $COMMAND: entering create_bridge - end"
81 # disable netfilter calls for bridge interface (they cause panick on 2.6.35 anyway)
83 # another option would be to accept the all forward packages for
84 # bridged interface like: -A FORWARD -m physdev --physdev-is-bridged -j ACCEPT
85 sysctl net.bridge.bridge-nf-call-iptables=0
86 sysctl net.bridge.bridge-nf-call-ip6tables=0
87 sysctl net.bridge.bridge-nf-call-arptables=0
90 #Getting host IP/masklen
91 address=$(ip addr show $if_lan | grep -v inet6 | grep inet | head --lines=1 | awk '{print $2;}')
92 [ -z "$address" ] && { echo "ERROR: Could not determine IP address for $if_lan" ; exit 1 ; }
94 broadcast=$(ip addr show $if_lan | grep -v inet6 | grep inet | head --lines=1 | awk '{print $4;}')
95 [ -z "$broadcast" ] && echo "WARNING: Could not determine broadcast address for $if_lan"
97 gateway=$(ip route show | grep default | awk '{print $3;}')
98 [ -z "$gateway" ] && echo "WARNING: Could not determine gateway IP"
101 # creating the bridge
102 echo "Creating public bridge interface $public_bridge"
103 brctl addbr $public_bridge
104 brctl addif $public_bridge $if_lan
105 echo "Activating promiscuous mode if_lan=$if_lan"
106 ip link set $if_lan up promisc on
108 # rely on dhcp to re assign IP..
109 echo "Starting dhclient on $public_bridge"
110 dhclient $public_bridge
113 #Reconfigure the routing table
114 echo "Configuring gateway=$gateway"
115 ip route add default via $gateway dev $public_bridge
116 ip route del default via $gateway dev $if_lan
117 # at this point we have an extra route like e.g.
119 #default via 138.96.112.250 dev br0
120 #138.96.112.0/21 dev em1 proto kernel scope link src 138.96.112.57
121 #138.96.112.0/21 dev br0 proto kernel scope link src 138.96.112.57
122 #192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1
123 route_dest=$(ip route show | grep -v default | grep "dev $public_bridge" | awk '{print $1;}')
124 ip route del $route_dest dev $if_lan
126 echo "========== $COMMAND: exiting create_bridge - beg"
129 echo "========== $COMMAND: exiting create_bridge - end"
138 if [[ -n "$@" ]] ; then
139 public_bridge="$1"; shift
141 public_bridge="$DEFAULT_PUBLIC_BRIDGE"
143 create_bridge_if_needed $public_bridge