# Routes override
#
# This is the simple interface to the db/iproutes file.  The function that
# interprets the value returned is routes_spec, provided there because it
# is of general use.

require iproutesdb crossbar
provide iproutes

relation -t bind,mx mx_records
relation -t bind,cname cname_records
relation -t bind,a a_records


lookup_list (lu_type, list) {
    local tmp res scr
    res=""
    for tmp in $(elements $list); do
        for scr in $(elements $($lu_type $tmp ||$(list $tmp))); do
            res="$res $scr"
        done
    done
    return $(list $res)
}


iproutes_neighbour (domain, address, A) {
	local tmp a b

        a=$(lookup_list mx_records $domain);
        a=$(lookup_list cname_records $a);
        a=$(lookup_list a_records $a);
        
        for b in $(elements $a); do
# We look for the deprecated channel! route.  If we find it, toss it through.
# elsewise take the last one we found.
            tmp=$(iproutesdb "$b") &&
                sift "$tmp" in
		.*!		tmp=$(routes_spec "$tmp" "$address" $A) &&
				    return $tmp ;;
                tfis
        done
	tmp=$(routes_spec "$tmp" "$address" $A) &&
	    return $tmp

#| The routes_spec function interprets the return value from the
#| iproutesdb lookup.

	return 1
}