#!/sbin/openrc-run
# Copyright 1999-2013 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

extra_commands="save"
extra_started_commands="reload"

IPSET_SAVE=${IPSET_SAVE:-/var/lib/ipset/rules-save}

depend() {
    before iptables ip6tables
}

checkconfig() {
    if [ ! -f "${IPSET_SAVE}" ] ; then
        eerror "Not starting ${SVCNAME}. First create some rules then run:"
        eerror "/etc/init.d/${SVCNAME} save"
        return 1
    fi
    return 0
}

start() {
    checkconfig || return 1
    ebegin "Loading ipset session"
    ipset restore < "${IPSET_SAVE}"
    eend $?
}

stop() {
    # check if there are any references to current sets

    if ! ipset list | gawk '
        ($1 == "References:") { refcnt += $2 }
        ($1 == "Type:" && $2 == "list:set") { set = 1 }
        (scan) { if ($0 != "") setcnt++; else { scan = 0; set = 0 } }
        (set && $1 == "Members:") {scan = 1}
        END { if ((refcnt - setcnt) > 0) exit 1 }
    '; then
        eerror "ipset is in use, can't stop"
        return 1
    fi

    if [ "${SAVE_ON_STOP}" = "yes" ] ; then
        save || return 1
    fi

    ebegin "Removing kernel IP sets"
    ipset flush
    ipset destroy
    eend $?
}

reload() {
    ebegin "Reloading ipsets"

    # Loading sets from a save file is only additive (there is no
    # automatic flushing or replacing). And, we can not remove sets
    # that are currently used in existing iptables rules.
    #
    # Instead, we create new temp sets for any set that is already
    # in use, and then atomically swap them into place.
    #
    # XXX: This does not clean out previously used ipsets that are
    # not in the new saved policy--it can't, because they may still
    # be referenced in the current iptables rules.

    # Build a list of all currently used sets (if any).
    running_ipset_list=$(ipset save | gawk '/^create/{printf "%s ",$2}')
	running_ipset_list="${running_ipset_list% }"
    # Build a regular expression that matches those set names.
    running_ipset_list_regex="$(echo "$running_ipset_list" | tr -s ' ' '|' )"

    # Load up sets from the save file, but rename any set that already
    # exists to a temporary name that we will swap later.
    if ! cat ${IPSET_SAVE} | sed -r "s/^(create|add) (${running_ipset_list_regex}) /\1 \2_atomic_temp /" | ipset restore ; then
        eend $? "Failed to load new ipsets"
    fi

    # Now for every set name that currently exists, atomically swap it
    # with the temporary new one we created, and then destroy the old set.
    for ipset_name in ${running_ipset_list} ; do
        ipset swap ${ipset_name} ${ipset_name}_atomic_temp || eend $? "Failed to swap in new ipset $ipset_name"
        ipset destroy ${ipset_name}_atomic_temp || eend $? "Failed to delete obsolete ipset ${ipset_name}_atomic_temp"
    done
    eend 0
}

save() {
    ebegin "Saving ipset session"
    touch "${IPSET_SAVE}"
    chmod 0600 "${IPSET_SAVE}"
    ipset save > "${IPSET_SAVE}"
    eend $?
}