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 #################### bridge initialization
38 function create_bridge_if_needed() {
43 public_bridge=$1; shift
45 # already created ? - we're done
46 ip addr show $public_bridge >& /dev/null && {
47 echo "Bridge already set up - skipping create_bridge_if_needed"
51 # find out the physical interface to bridge onto
52 if_lan=$(discover_interface)
54 ip addr show $if_lan &>/dev/null || {
55 echo "Cannot use interface $if_lan - exiting"
59 #################### bride initialization
60 check_yum_installed bridge-utils
62 echo "========== $COMMAND: entering create_bridge - beg"
67 echo "========== $COMMAND: entering create_bridge - end"
69 # disable netfilter calls for bridge interface (they cause panick on 2.6.35 anyway)
71 # another option would be to accept the all forward packages for
72 # bridged interface like: -A FORWARD -m physdev --physdev-is-bridged -j ACCEPT
73 sysctl net.bridge.bridge-nf-call-iptables=0
74 sysctl net.bridge.bridge-nf-call-ip6tables=0
75 sysctl net.bridge.bridge-nf-call-arptables=0
78 #Getting host IP/masklen
79 address=$(ip addr show $if_lan | grep -v inet6 | grep inet | head --lines=1 | awk '{print $2;}')
80 [ -z "$address" ] && { echo "ERROR: Could not determine IP address for $if_lan" ; exit 1 ; }
82 broadcast=$(ip addr show $if_lan | grep -v inet6 | grep inet | head --lines=1 | awk '{print $4;}')
83 [ -z "$broadcast" ] && echo "WARNING: Could not determine broadcast address for $if_lan"
85 gateway=$(ip route show | grep default | awk '{print $3;}')
86 [ -z "$gateway" ] && echo "WARNING: Could not determine gateway IP"
90 echo "Creating public bridge interface $public_bridge"
91 brctl addbr $public_bridge
92 brctl addif $public_bridge $if_lan
93 echo "Activating promiscuous mode if_lan=$if_lan"
94 ip link set $if_lan up promisc on
96 # rely on dhcp to re assign IP..
97 echo "Starting dhclient on $public_bridge"
98 dhclient $public_bridge
101 #Reconfigure the routing table
102 echo "Configuring gateway=$gateway"
103 ip route add default via $gateway dev $public_bridge
104 ip route del default via $gateway dev $if_lan
105 # at this point we have an extra route like e.g.
107 #default via 138.96.112.250 dev br0
108 #138.96.112.0/21 dev em1 proto kernel scope link src 138.96.112.57
109 #138.96.112.0/21 dev br0 proto kernel scope link src 138.96.112.57
110 #192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1
111 route_dest=$(ip route show | grep -v default | grep "dev $public_bridge" | awk '{print $1;}')
112 ip route del $route_dest dev $if_lan
114 echo "========== $COMMAND: exiting create_bridge - beg"
117 echo "========== $COMMAND: exiting create_bridge - end"
126 if [[ -n "$@" ]] ; then
127 public_bridge="$1"; shift
129 public_bridge="$DEFAULT_PUBLIC_BRIDGE"
131 create_bridge_if_needed $public_bridge