#! /bin/sh

# Copyright (c) 2011 Nicira, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

usage() {
    UTIL=$(basename $0)
    cat <<EOF
${UTIL}: Provides helper functions to save Open vSwitch's configuration.
usage: $0 COMMAND

Commands:
 save-interfaces        Outputs a shell script on stdout that will restore
                        the current kernel configuration of the specified
                        network interfaces, as well as the system iptables
                        configuration.
 save-flows             Outputs a shell script on stdout that will restore
                        Openflow flows of each Open vSwitch bridge.
 save-ofports           Outputs a shell script on stdout that will restore
                        the ofport value across a force-reload-kmod.
This script is meant as a helper for the Open vSwitch init script commands.
EOF
}

PATH=/sbin:/bin:/usr/sbin:/usr/bin

missing_program () {
    save_IFS=$IFS
    IFS=:
    for dir in $PATH; do
        IFS=$save_IFS
        if test -x $dir/$1; then
            return 1
        fi
    done
    IFS=$save_IFS
    return 0
}

save_interfaces () {
    if missing_program ip; then
        echo "$0: ip not found in $PATH" >&2
        exit 1
    fi

    if test "$#" = 0; then
        exit 0
    fi

    devs="$@"
    for dev in $devs; do
        state=`ip link show dev $dev` || continue

        echo "# $dev"
        # Link state (Ethernet addresses, up/down, ...)
        linkcmd=
        case $state in
            *"state UP"* | *[,\<]"UP"[,\>]* )
                linkcmd="$linkcmd up"
                ;;
            *"state DOWN"*)
                linkcmd="$linkcmd down"
                ;;
        esac
        if expr "$state" : '.*\bdynamic\b' > /dev/null; then
            linkcmd="$linkcmd dynamic"
        fi
        if qlen=`expr "$state" : '.*qlen \([0-9]+\)'`; then
            linkcmd="$linkcmd txqueuelen $qlen"
        fi
        if hwaddr=`expr "$state" : '.*link/ether \([^ ]*\)'`; then
            linkcmd="$linkcmd address $hwaddr"
        fi
        if brd=`expr "$state" : '.*brd \([^ ]*\)'`; then
            linkcmd="$linkcmd broadcast $brd"
        fi
        if mtu=`expr "$state" : '.*mtu \([0-9]+\)'`; then
            linkcmd="$linkcmd mtu $mtu"
        fi
        if test -n "$linkcmd"; then
            echo ip link set dev $dev down # Required to change hwaddr.
            echo ip link set dev $dev $linkcmd
        fi

        # IP addresses (including IPv6).
        echo "ip addr flush dev $dev 2>/dev/null" # Suppresses "Nothing to flush".
        ip addr show dev $dev | while read addr; do
            set -- $addr

            # Check and trim family.
            family=$1
            shift
            case $family in
                inet | inet6) ;;
                *) continue ;;
            esac

            # Trim device off the end--"ip" insists on having "dev" precede it.
            addrcmd=
            while test $# != 0; do
                case $1 in
                    dynamic)
                        # Omit kernel-maintained route.
                        continue 2
                        ;;
                    scope)
                        if test "$2" = link; then
                            # Omit route derived from IP address, e.g.
                            # 172.16.0.0/16 derived from 172.16.12.34.
                            continue 2
                        fi
                        ;;
                    "$dev"|"$dev:"*)
                        # Address label string
                        addrcmd="$addrcmd label $1"
                        shift
                        continue
                        ;;
                esac
                addrcmd="$addrcmd $1"
                shift
            done
            if test "$1" != "$dev"; then
                addrcmd="$addrcmd $1"
            fi

            echo ip -f $family addr add $addrcmd dev $dev
        done

        # Routes.
        echo "ip route flush dev $dev proto boot 2>/dev/null" # Suppresses "Nothing to flush".
        ip route show dev $dev | while read route; do
            # "proto kernel" routes are installed by the kernel automatically.
            case $route in
                *" proto kernel "*) continue ;;
            esac

            echo "ip route add $route dev $dev"
        done

        echo
    done

    if missing_program iptables-save; then
        echo "# iptables-save not found in $PATH, not saving iptables state"
    else
        echo "# global"
        echo "iptables-restore <<'EOF'"
        iptables-save
        echo "EOF"
    fi
}

save_flows () {
    if missing_program ovs-ofctl; then
        echo "$0: ovs-ofctl not found in $PATH" >&2
        exit 1
    fi

    for bridge in "$@"; do
        echo "ovs-ofctl add-flows ${bridge} - << EOF"
        ovs-ofctl dump-flows "${bridge}" | sed -e '/NXST_FLOW/d' \
            -e 's/\(idle\|hard\)_age=[^,]*,//g'
        echo "EOF"
    done
}

ovs_vsctl () {
    ovs-vsctl --no-wait --timeout=1 "$@"
}

save_ofports ()
{
    if missing_program ovs-vsctl; then
        echo "$0: ovs-vsctl not found in $PATH" >&2
        exit 1
    fi

    for bridge in "$@"; do
        count=0
        for iface in `ovs_vsctl list-ifaces ${bridge}`; do
            ofport=`ovs_vsctl get interface ${iface} ofport`
            [ "${count}" -eq 0 ] && cmd="ovs-vsctl --no-wait --timeout=1"
            cmd="${cmd} -- --if-exists set interface "${iface}" \
                     ofport_request="${ofport}""

            # Run set interface command on 50 ports at a time.
            count=`expr ${count} + 1`
            [ "${count}" -eq 50 ] && count=0 && echo "${cmd}" && cmd=""
        done
        echo "${cmd}"
    done
}

while [ $# -ne 0 ]
do
    case $1 in
        "save-flows")
            shift
            save_flows "$@"
            exit 0
            ;;
        "save-interfaces")
            shift
            save_interfaces "$@"
            exit 0
            ;;
        "save-ofports")
            shift
            save_ofports "$@"
            exit 0
            ;;
        -h | --help)
            usage
            exit 0
            ;;
        *)
            echo >&2 "$0: unknown command \"$1\" (use --help for help)"
            exit 1
            ;;
    esac
done

exit 0