-- binary
00 03 # class
01 # type/masked
20 # length
00 00 00 00 00 00 00 00 # value
00 00 00 00 00 00 00 00 # ...
ff ff ff fe ff ff ff ff # mask - Only ports 0, 17, 96 are selected (and thus are zero)
ff ff ff ff ff fd ff fe # ...
-- python
ofp.oxm.bsn_in_ports_128_masked(set(), set(range(0,128)) - set((0, 17,96)))
-- c
obj = of_oxm_bsn_in_ports_128_masked_new(OF_VERSION_1_3);
{
    of_bitmap_128_t bmap = { 0, 0 };
    of_oxm_bsn_in_ports_128_masked_value_set(obj, bmap);
}
{
    of_bitmap_128_t bmap = { 0xfffffffeffffffff , 0xfffffffffffdfffe };
    of_oxm_bsn_in_ports_128_masked_value_mask_set(obj, bmap);
}
-- java
OFPortMap portmap = OFPortMap.ofPorts(OFPort.of(0), OFPort.of(17), OFPort.of(96));
builder.setValue(portmap.getValue());
builder.setMask(portmap.getMask());