router-functions.sh

#!/bin/sh

ip_flip() {
        if [ $1 -eq 4 ]
        then
                FIRST=$(echo $TUNNEL_IP | cut -d . -f 1-3).
                LAST=$(echo $TUNNEL_IP | cut -d . -f 4)
        fi

        if [ $1 -eq 6 ]
        then
                FIRST=$(echo $TUNNEL_IP | awk -F: '{ for (i = 1; i < NF; i++) printf "%s:", $i }')
                LAST=$(echo $TUNNEL_IP | awk -F: '{ print $NF }')
        fi

        if [ $((LAST % 2)) -eq 0 ]
        then
                LAST=$((LAST - 1))
        else
                LAST=$((LAST + 1))
        fi

        PEER_IP=${FIRST}${LAST}
}

ping_endpoint() {
        # $1 NETIF_NAME

        TAG='['$1']'
        UCI_SECTION=network.${1}
        PROTO="$(uci get ${UCI_SECTION}.proto)"

        if [ $? -gt 0 ]
        then
                echo $TAG 'Interface not found!'
                return 1
        fi

        PEER_IP="$(uci get ${UCI_SECTION}.peeraddr)"

        if [ $? -gt 0 ]
        then
                echo $TAG 'Error getting interface IP!'
                return 1
        fi

        echo $TAG Current IP: ${PEER_IP}

        ping -c 1 -W 1 -q ${PEER_IP} > /dev/null

        if [ $? -gt 0 ]
        then
                echo $TAG 'PING FAILED - Host is down!'
        else
                echo $TAG 'Host is up'
        fi

        if [ $PROTO = "6in4" ]
        then
                TUNNEL_IP="$(uci get ${UCI_SECTION}.ip6addr | cut -d / -f 1)"
                ip_flip 6
        fi

        if [ $PROTO = "gre" ]
        then
                LINK_IF_NAME=l_${1:1}
                TUNNEL_IP="$(uci get network.$LINK_IF_NAME.ipaddr)"
                ip_flip 4
        fi

        if [ -n $PEER_IP ]
        then
                echo $TAG Peer IP: ${PEER_IP}
        fi

        ping -c 1 -W 1 -q ${PEER_IP} > /dev/null

        if [ $? -gt 0 ]
        then
                echo $TAG 'PING FAILED - Host is down!'
        else
                echo $TAG 'Host is up'
        fi
}

check_fix_ip() {
        # $1 NETIF_NAME
        # $2 HOSTNAME

        TAG='['$1']'

        echo $TAG Processing interface...

        UCI_SECTION=network
        UCI_KEY=${UCI_SECTION}.${1}.peeraddr

        CURR_IP="$(uci get $UCI_KEY)"

        if [ $? -gt 0 ]
        then
                echo 'Error getting interface IP!'
                return 1
        fi

        echo $TAG Looking up hostname ${2}...
        CORRECT_IP="$(nslookup $2 2> /dev/null | grep '^Address' | cut -d ' ' -f 3 | grep -vF ':')"

        if [ "${CURR_IP}" = "${CORRECT_IP}" ]
        then
                echo $TAG IP ${CURR_IP} not changed
                return 0
        fi

        echo $TAG IP changed: ${CURR_IP} '->' ${CORRECT_IP}, updating...
        uci set "${UCI_KEY}=${CORRECT_IP}"
        uci commit "${UCI_SECTION}"
        ifdown $1
        ifup $1
        echo $TAG IP updated
}

# Examples
# check_fix_ip if_name hostname
# ping_endpoint if_name