-- binary
01 0a # version / type
00 15 # length
12 34 56 78 # xid
ab cd ef 01 # buffer_id
00 09 # total_len
ff fe # in_port
01 # reason
00 # pad
61 62 63 # data
-- python
ofp.message.packet_in(
    xid=0x12345678,
    buffer_id=0xabcdef01,
    total_len=9,
    in_port=ofp.OFPP_LOCAL,
    reason=ofp.OFPR_ACTION,
    data='abc')
-- c
obj = of_packet_in_new(OF_VERSION_1_0);
of_packet_in_buffer_id_set(obj, 0xabcdef01);
{
    of_octets_t data = { .bytes=3, .data=(uint8_t *)"\x61\x62\x63" };
    of_packet_in_data_set(obj, &data);
}
of_packet_in_in_port_set(obj, 65534);
of_packet_in_reason_set(obj, 1);
of_packet_in_total_len_set(obj, 9);
of_packet_in_xid_set(obj, 305419896);
-- java
builder
   .setXid(0x12345678)
   .setBufferId(OFBufferId.of(0xabcdef01))
   .setTotalLen(9)
   .setInPort(OFPort.LOCAL)
   .setReason(OFPacketInReason.ACTION)
   .setData(new byte[] { 0x61, 0x62, 0x63 } );