ds_walk_svcs
(void) ds_walk_svcs(ds_svc_port_up, port);
(void) ds_walk_svcs(ds_svc_register_onport_walker, port);
idx = ds_walk_svcs(ds_svc_isfree, NULL);
idx = ds_walk_svcs(ds_svc_isfree, NULL);
(void) ds_walk_svcs(ds_svc_unregister, port);
(void) ds_walk_svcs(ds_svc_free, NULL);
int ds_walk_svcs(svc_cb_t svc_cb, void *arg);