IBD_DEF_MAX_SDU
#define IBD_DEF_MAX_MTU (IBD_DEF_MAX_SDU + IPOIB_HDRSIZE)
macp->m_multicast_sdu = IBD_DEF_MAX_SDU;
macp->m_max_sdu = IBD_DEF_MAX_SDU;
macp->m_multicast_sdu = IBD_DEF_MAX_SDU;
macp->m_max_sdu = IBD_DEF_MAX_SDU;