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- #!/bin/sh -e
- #
- # Libvirt qemu hook to magically connect VM bridge interfaces to desired untagged Vlan
- #
- # IF
- # * the VM interface if configured to be connected to a bridge,
- # * the bridge is configured to be vlan aware (vlan_filtering = 1)
- # * the VM interface name ends with _vXXXX with XXXX being a one to four
- # digit number
- # the interface will be configured as an untagged port connected to vlan XXXX.
- #
- # See <man bridge> for more details about vlan aware bridges.
- #
- # Maximilian Wilhelm <max@sdn.clinic>
- # -- Wed, 31 Aug 2016 20:48:02 +0200
- my_name="qemu-magic"
- # We only care for the "started" event.
- if [ "$2" != 'started' ]; then
- exit 0
- fi
- if ! which xmlstarlet >/dev/null 2>/dev/null; then
- logger -t "${my_name}" "ERROR: xmlstarlet not found. Dying of shame."
- echo "${my_name}: ERROR: xmlstarlet not found. Dying of shame." >&2
- exit 1
- fi
- # Save domain XML which was given to us on stdin, so we can poke around in it.
- # Yes this is ugly. But I don't see another way storing the MTU for an device
- # within the libvirt domain config when NOT using a libvirt network.
- # If you happen to now a better way than specifying this within custom domain
- # metadata PLEASE let me know.
- export domain_xml="$(cat)"
- echo "${domain_xml}" | xmlstarlet sel -t -m '//interface[@type="bridge"]' -v 'concat(target/@dev, " ", source/@bridge)' --nl | while read iface bridge; do
- if [ ! -d "/sys/class/net/${bridge}/bridge" ]; then
- logger -t "${my_name}" "Bridge \"${bridge}\" for iface \"${iface}\" doesn't exist or isn't a bridge."
- exit 2
- fi
- #
- # Check if this kernel supports vlan-aware bridges and if ${bridge} is one
- vlan_filtering=0
- if [ -f "/sys/class/net/${bridge}/bridge/vlan_filtering" ]; then
- vlan_filtering=$(cat "/sys/class/net/${bridge}/bridge/vlan_filtering")
- fi
- # If the interface is named *_vXXXX, with XXXX being a 1-4 digit number
- # we assume that this iface should be connected to Vlan XXXX with
- # an untagged port.
- vlan_id=$(echo ${iface} | grep -o '_v[0-9]\{1,4\}$' | cut -c3-)
- # If vlan filtering is activated and we found a vlan id, kindly do the needful.
- if [ "${vlan_filtering}" -a "${vlan_id}" ]; then
- # Remove association with vlan 1 and add association with
- # vlan $vlan_id with packages being sent out untagged and
- # untagged ingress packets get tagged accordingly.
- bridge vlan del vid 1 dev "${iface}"
- bridge vlan add vid "${vlan_id}" dev "${iface}" pvid untagged
- logger -t "${my_name}" "Configured untagged pvid ${vlan_id} for ${iface} in bridge ${bridge}."
- # If vlan filtering isn't activated or supported but we found a vlan id,
- # this probably is an error!
- elif [ ! "${vlan_filtering}" -a "${vlan_id}" ]; then
- logger -t "${my_name}" -p user.error "ERROR: Should configure untagged pvid ${vlan_id} for ${iface} in bridge ${bridge}, but bridge does not support vlan filtering!"
- fi
- # We dont' care about "no vlan filtering AND no vlan id" as well as "vlan filtering AND no vlan id"
- mtu=$(echo "${domain_xml}" | xmlstarlet sel -t -m "//metadata/ffho/interface[@name='${iface}']" -v 'mtu/@size' --nl || true)
- if [ "${mtu}" ]; then
- ip link set mtu "${mtu}" dev "${iface}"
- logger -t "${my_name}" "Setting MTU of ${iface} to ${mtu}."
- fi
- # If there is an configuration stanza in /etc/network/interfaces
- # for this interfaces, we try to get it up and running. Proceed
- # with fingers crossed.
- if grep -q "^iface\s\+${iface}" /etc/network/interfaces; then
- if ifup $iface; then
- logger -t "${my_name}" "ifup'ed ${iface}."
- else
- logger -t "${my_name}" -p user.error "ifup ${iface} FAILED."
- fi
- fi
- done
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