ds_init_req_t
ds_init_req_t *init_req;
msglen = DS_HDR_SZ + sizeof (ds_init_req_t);
hdr->payload_len = sizeof (ds_init_req_t);
init_req = (ds_init_req_t *)((caddr_t)hdr + DS_HDR_SZ);
ds_init_req_t *req;
size_t explen = DS_MSG_LEN(ds_init_req_t);
req = (ds_init_req_t *)(buf + DS_HDR_SZ);