The mask that is applied to the match process.
After adjusting this mask for the offset, only those
bits in the received packet that correspond to bits
set in this mask are relevant for further processing
by the match algorithm. The offset is applied to
filterPktDataMask in the same way it is applied to
the filter. For the purposes of the matching
algorithm, if the associated filterPktData object
is longer than this mask, this mask is conceptually
extended with '1' bits until it reaches the
length of the filterPktData object.
This object may not be modified if the associated
filterStatus object is equal to valid(1).