mirror of
https://github.com/xen-project/xen.git
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Keir Fraser
6e91413a40
Allow the network bridging setup script to choose an alternative network interface if it is determined that the root is mounted using NFS, which is assumed to be done over the NIC serving the default gw. In this case the prefix of the device is used to find other devices, i.e., if eth0 is the default device an alternative device may be an other ones starting with 'eth'. Signed-off-by: Stefan Berger <stefanb@us.ibm.com>
299 lines
7.1 KiB
Bash
Executable File
299 lines
7.1 KiB
Bash
Executable File
#!/bin/bash
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#============================================================================
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# Default Xen network start/stop script.
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# Xend calls a network script when it starts.
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# The script name to use is defined in /etc/xen/xend-config.sxp
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# in the network-script field.
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#
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# This script creates a bridge (default ${netdev}), adds a device
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# (defaults to the device on the default gateway route) to it, copies
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# the IP addresses from the device to the bridge and adjusts the routes
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# accordingly.
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#
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# If all goes well, this should ensure that networking stays up.
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# However, some configurations are upset by this, especially
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# NFS roots. If the bridged setup does not meet your needs,
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# configure a different script, for example using routing instead.
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#
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# Usage:
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#
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# network-bridge (start|stop|status) {VAR=VAL}*
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#
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# Vars:
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#
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# bridge The bridge to use (default ${netdev}).
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# netdev The interface to add to the bridge (default gateway device).
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# antispoof Whether to use iptables to prevent spoofing (default no).
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#
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# Internal Vars:
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# pdev="p${netdev}"
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# tdev=tmpbridge
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#
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# start:
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# Creates the bridge as tdev
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# Copies the IP and MAC addresses from pdev to bridge
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# Renames netdev to be pdev
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# Renames tdev to bridge
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# Enslaves pdev to bridge
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#
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# stop:
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# Removes pdev from the bridge
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# Transfers addresses, routes from bridge to pdev
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# Renames bridge to tdev
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# Renames pdev to netdev
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# Deletes tdev
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#
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# status:
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# Print addresses, interfaces, routes
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#
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#============================================================================
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dir=$(dirname "$0")
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. "$dir/xen-script-common.sh"
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. "$dir/xen-network-common.sh"
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findCommand "$@"
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evalVariables "$@"
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is_network_root () {
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local rootfs=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/") { print $3; }}' /etc/mtab)
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local rootopts=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/") { print $4; }}' /etc/mtab)
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[[ "$rootfs" =~ "^nfs" ]] || [[ "$rootopts" =~ "_netdev" ]] && return 0 || return 1
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}
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find_alt_device () {
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local interf=$1
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local prefix=${interf%[[:digit:]]}
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local ifs=$(ip link show | grep " $prefix" |\
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gawk '{ printf ("%s",substr($2,1,length($2)-1)) }' |\
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sed s/$interf//)
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echo "$ifs"
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}
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netdev=${netdev:-$(ip route list | awk '/^default / { print $NF }' |
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sed 's/.* dev //')}
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if is_network_root ; then
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altdevs=$(find_alt_device $netdev)
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for netdev in $altdevs; do break; done
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if [ -z "$netdev" ]; then
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[ -x /usr/bin/logger ] && /usr/bin/logger "network-bridge: bridging not supported on network root; not starting"
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exit
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fi
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fi
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netdev=${netdev:-eth0}
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bridge=${bridge:-${netdev}}
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antispoof=${antispoof:-no}
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pdev="p${netdev}"
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tdev=tmpbridge
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get_ip_info() {
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addr_pfx=`ip addr show dev $1 | egrep '^ *inet' | sed -e 's/ *inet //' -e 's/ .*//'`
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gateway=`ip route show dev $1 | fgrep default | sed 's/default via //'`
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}
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do_ifup() {
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if ! ifup $1 ; then
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if [ ${addr_pfx} ] ; then
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# use the info from get_ip_info()
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ip addr flush $1
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ip addr add ${addr_pfx} dev $1
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ip link set dev $1 up
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[ ${gateway} ] && ip route add default via ${gateway}
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fi
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fi
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}
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# Usage: transfer_addrs src dst
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# Copy all IP addresses (including aliases) from device $src to device $dst.
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transfer_addrs () {
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local src=$1
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local dst=$2
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# Don't bother if $dst already has IP addresses.
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if ip addr show dev ${dst} | egrep -q '^ *inet ' ; then
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return
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fi
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# Address lines start with 'inet' and have the device in them.
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# Replace 'inet' with 'ip addr add' and change the device name $src
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# to 'dev $src'.
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ip addr show dev ${src} | egrep '^ *inet ' | sed -e "
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s/inet/ip addr add/
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s@\([0-9]\+\.[0-9]\+\.[0-9]\+\.[0-9]\+/[0-9]\+\)@\1@
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s/${src}/dev ${dst}/
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" | sh -e
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# Remove automatic routes on destination device
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ip route list | sed -ne "
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/dev ${dst}\( \|$\)/ {
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s/^/ip route del /
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p
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}" | sh -e
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}
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# Usage: transfer_routes src dst
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# Get all IP routes to device $src, delete them, and
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# add the same routes to device $dst.
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# The original routes have to be deleted, otherwise adding them
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# for $dst fails (duplicate routes).
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transfer_routes () {
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local src=$1
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local dst=$2
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# List all routes and grep the ones with $src in.
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# Stick 'ip route del' on the front to delete.
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# Change $src to $dst and use 'ip route add' to add.
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ip route list | sed -ne "
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/dev ${src}\( \|$\)/ {
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h
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s/^/ip route del /
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P
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g
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s/${src}/${dst}/
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s/^/ip route add /
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P
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d
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}" | sh -e
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}
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##
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# link_exists interface
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#
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# Returns 0 if the interface named exists (whether up or down), 1 otherwise.
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#
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link_exists()
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{
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if ip link show "$1" >/dev/null 2>/dev/null
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then
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return 0
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else
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return 1
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fi
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}
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# Set the default forwarding policy for $dev to drop.
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# Allow forwarding to the bridge.
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antispoofing () {
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iptables -P FORWARD DROP
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iptables -F FORWARD
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iptables -A FORWARD -m physdev --physdev-in ${pdev} -j ACCEPT
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}
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# Usage: show_status dev bridge
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# Print ifconfig and routes.
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show_status () {
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local dev=$1
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local bridge=$2
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echo '============================================================'
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ip addr show ${dev}
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ip addr show ${bridge}
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echo ' '
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brctl show ${bridge}
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echo ' '
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ip route list
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echo ' '
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route -n
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echo '============================================================'
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}
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op_start () {
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if [ "${bridge}" = "null" ] ; then
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return
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fi
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if link_exists "$pdev"; then
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# The device is already up.
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return
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fi
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create_bridge ${tdev}
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preiftransfer ${netdev}
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transfer_addrs ${netdev} ${tdev}
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if ! ifdown ${netdev}; then
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# If ifdown fails, remember the IP details.
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get_ip_info ${netdev}
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ip link set ${netdev} down
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ip addr flush ${netdev}
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fi
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ip link set ${netdev} name ${pdev}
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ip link set ${tdev} name ${bridge}
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setup_bridge_port ${pdev}
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add_to_bridge2 ${bridge} ${pdev}
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do_ifup ${bridge}
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if [ ${antispoof} = 'yes' ] ; then
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antispoofing
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fi
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}
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op_stop () {
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if [ "${bridge}" = "null" ]; then
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return
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fi
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if ! link_exists "$bridge"; then
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return
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fi
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transfer_addrs ${bridge} ${pdev}
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if ! ifdown ${bridge}; then
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get_ip_info ${bridge}
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fi
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ip link set ${pdev} down
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ip addr flush ${bridge}
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brctl delif ${bridge} ${pdev}
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ip link set ${bridge} down
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ip link set ${bridge} name ${tdev}
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ip link set ${pdev} name ${netdev}
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do_ifup ${netdev}
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brctl delbr ${tdev}
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}
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# adds $dev to $bridge but waits for $dev to be in running state first
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add_to_bridge2() {
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local bridge=$1
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local dev=$2
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local maxtries=10
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echo -n "Waiting for ${dev} to negotiate link."
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ip link set ${dev} up
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for i in `seq ${maxtries}` ; do
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if ifconfig ${dev} | grep -q RUNNING ; then
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break
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else
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echo -n '.'
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sleep 1
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fi
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done
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if [ ${i} -eq ${maxtries} ] ; then echo -n '(link isnt in running state)' ; fi
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echo
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add_to_bridge ${bridge} ${dev}
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}
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case "$command" in
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start)
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op_start
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;;
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stop)
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op_stop
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;;
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status)
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show_status ${netdev} ${bridge}
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;;
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*)
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echo "Unknown command: $command" >&2
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echo 'Valid commands are: start, stop, status' >&2
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exit 1
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esac
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