ds_reg_ack_t
msglen = DS_MSG_LEN(ds_reg_ack_t);
hdr->payload_len = sizeof (ds_reg_ack_t);
ack = (ds_reg_ack_t *)(msg + DS_HDR_SZ);
ds_reg_ack_t *ack;
size_t explen = DS_MSG_LEN(ds_reg_ack_t);
ack = (ds_reg_ack_t *)(buf + DS_HDR_SZ);
ds_reg_ack_t *ack;