## Pass 1. Establish the from_NAME and to_NAME constants, and the
## netclass's mask bit.
+ trace "netclass $name = $netclassindex"
eval from_$name=$(( $netclassindex << $BIT_FROM ))
eval to_$name=$(( $netclassindex << $BIT_TO ))
eval _mask_$name=$(( 1 << ($netclassindex + $BIT_MASK) ))