#
# Copyright (c) 2005 XenSource Ltd.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of version 2.1 of the GNU Lesser General Public
# License as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; If not, see <http://www.gnu.org/licenses/>.
#


# Gentoo doesn't have ifup/ifdown, so we define appropriate alternatives.

# Other platforms just use ifup / ifdown directly.

##
# preiftransfer
#
# @param $1 The current name for the physical device, which is also the name
#           that the virtual device will take once the physical device has
#           been renamed.

if ! which ifup >/dev/null 2>/dev/null
then
  preiftransfer()
  {
    true
  }
  ifup()
  {
    false
  }
  ifdown()
  {
    false
  }
else
  preiftransfer()
  {
    true
  }
fi


first_file()
{
  t="$1"
  shift
  for file in $@
  do
    if [ "$t" "$file" ]
    then
      echo "$file"
      return
    fi
  done
}

find_dhcpd_conf_file()
{
  first_file -f /etc/dhcp/dhcpd.conf /etc/dhcp3/dhcpd.conf /etc/dhcpd.conf
}


find_dhcpd_init_file()
{
  first_file -x /etc/init.d/{isc-dhcp-server,dhcp-server,dhcp3-server,dhcp,dhcpd}
}

find_dhcpd_arg_file()
{
  first_file -f /etc/sysconfig/dhcpd /etc/defaults/dhcp /etc/default/dhcp-server /etc/default/dhcp3-server
}

# configure interfaces which act as pure bridge ports:
_setup_bridge_port() {
    local dev="$1"
    local virtual="$2"

    # take interface down ...
    ip link set dev ${dev} down

    if [ $virtual -ne 0 ] ; then
        # Initialise a dummy MAC address. We choose the numerically
        # largest non-broadcast address to prevent the address getting
        # stolen by an Ethernet bridge for STP purposes.
        # (FE:FF:FF:FF:FF:FF)
        ip link set dev ${dev} address fe:ff:ff:ff:ff:ff || true
    fi

    # ... and configure it
    ip address flush dev ${dev}
}

setup_physical_bridge_port() {
    _setup_bridge_port $1 0
}
setup_virtual_bridge_port() {
    _setup_bridge_port $1 1
}

# Usage: create_bridge bridge
create_bridge () {
    local bridge=$1

    # Don't create the bridge if it already exists.
    if [ ! -e "/sys/class/net/${bridge}/bridge" ]; then
        if which brctl >&/dev/null; then
            brctl addbr ${bridge}
            brctl stp ${bridge} off
            brctl setfd ${bridge} 0
        else
            ip link add name ${bridge} type bridge stp_state 0 forward_delay 0
        fi
    fi
}

# Usage: add_to_bridge bridge dev
add_to_bridge () {
    local bridge=$1
    local dev=$2

    # Don't add $dev to $bridge if it's already on the bridge.
    if [ ! -e "/sys/class/net/${bridge}/brif/${dev}" ]; then
        log debug "adding $dev to bridge $bridge"
        if which brctl >&/dev/null; then
            brctl addif ${bridge} ${dev}
        else
            ip link set ${dev} master ${bridge}
        fi
    else
        log debug "$dev already on bridge $bridge"
    fi

    ip link set dev ${dev} up
}

remove_from_bridge () {
    local bridge=$1
    local dev=$2

    do_without_error ip link set dev ${dev} down

    # Don't remove $dev from $bridge if it's not on the bridge.
    if [ -e "/sys/class/net/${bridge}/brif/${dev}" ]; then
        log debug "removing $dev from bridge $bridge"
        if which brctl >&/dev/null; then
            do_without_error brctl delif ${bridge} ${dev}
        else
            do_without_error ip link set ${dev} nomaster
        fi
    else
        log debug "$dev not on bridge $bridge"
    fi
}

# Usage: set_mtu bridge dev
set_mtu () {
    local bridge=$1
    local dev=$2
    local type_if=$3

    XENBUS_PATH="${XENBUS_PATH:?}"

    local mtu=$(xenstore_read_default "$XENBUS_PATH/mtu" "")
    if [ -z "$mtu" ]
    then
        mtu="`ip link show dev ${bridge}| awk '/mtu/ { print $5 }'`"
        if [ -n "$mtu" ]
        then
            log debug "$bridge MTU is $mtu"
        fi
    fi
    if [ -n "$mtu" ] && [ "$mtu" -gt 0 ]
    then
        log debug "setting $dev MTU to $mtu"
        ip link set dev ${dev} mtu ${mtu} || :

        if [ ${type_if} = vif ]
        then
            local dev_=${dev#vif}
            local domid=${dev_%.*}
            local devid=${dev_#*.}

            local FRONTEND_PATH="/local/domain/$domid/device/vif/$devid"

            xenstore_write "$FRONTEND_PATH/mtu" ${mtu}
        fi
    fi
}