ofp_header
struct ofp_header cfg_oh; /* OpenFlow header */
struct ofp_header swf_oh; /* OpenFlow header */
struct ofp_header pin_oh; /* OpenFlow header */
struct ofp_header pout_oh; /* OpenFlow header */
struct ofp_header fm_oh; /* OpenFlow header */
struct ofp_header fr_oh;
struct ofp_header err_oh;
struct ofp_header gm_oh;
struct ofp_header mp_oh;
bp += sizeof(struct ofp_header);
length -= sizeof(struct ofp_header);
if (ohlen > sizeof(struct ofp_header) &&
struct ofp_header *oh;
oh = (struct ofp_header *)bp;