#! /bin/sh

# Copyright (c) 2011 Nicira Networks, 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.

if test "X$1" = X--help; then
    cat <<EOF
$0: saves the kernel configuration of network interfaces
usage: $0 NETDEV...

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.

This script is meant as a helper for the Open vSwitch init
script "force-reload-kmod" command.
EOF
    exit 0
fi

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

if test "$#" = 0; then
    echo "# $0: no parameters given (use \"$0 --help\" for help)"
fi

devs=$*
for dev in $devs; do
    state=`ip link show $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 down # Required to change hwaddr.
        echo ip link set $dev $linkcmd
    fi

    # IP addresses (including IPv6).
    echo "ip addr flush $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

exit 0