+int
+vppcom_session_read_segments (uint32_t session_handle,
+ vppcom_data_segments_t ds)
+{
+ vcl_worker_t *wrk = vcl_worker_get_current ();
+ int n_read = 0, rv, is_nonblocking;
+ vcl_session_t *s = 0;
+ svm_fifo_t *rx_fifo;
+ svm_msg_q_msg_t msg;
+ session_event_t *e;
+ svm_msg_q_t *mq;
+ u8 is_ct;
+
+ s = vcl_session_get_w_handle (wrk, session_handle);
+ if (PREDICT_FALSE (!s || s->is_vep))
+ return VPPCOM_EBADFD;
+
+ if (PREDICT_FALSE (!vcl_session_is_readable (s)))
+ {
+ session_state_t state = s->session_state;
+ rv = ((state & STATE_DISCONNECT) ? VPPCOM_ECONNRESET : VPPCOM_ENOTCONN);
+ return rv;
+ }
+
+ is_nonblocking = VCL_SESS_ATTR_TEST (s->attr, VCL_SESS_ATTR_NONBLOCK);
+ is_ct = vcl_session_is_ct (s);
+ mq = is_ct ? s->our_evt_q : wrk->app_event_queue;
+ rx_fifo = s->rx_fifo;
+
+ if (svm_fifo_is_empty (rx_fifo))
+ {
+ if (is_nonblocking)
+ {
+ svm_fifo_unset_event (rx_fifo);
+ return VPPCOM_OK;
+ }
+ while (svm_fifo_is_empty (rx_fifo))
+ {
+ svm_fifo_unset_event (rx_fifo);
+ svm_msg_q_lock (mq);
+ if (svm_msg_q_is_empty (mq))
+ svm_msg_q_wait (mq);
+
+ svm_msg_q_sub_w_lock (mq, &msg);
+ e = svm_msg_q_msg_data (mq, &msg);
+ svm_msg_q_unlock (mq);
+ if (!vcl_is_rx_evt_for_session (e, s->session_index, is_ct))
+ {
+ vcl_handle_mq_ctrl_event (wrk, e);
+ svm_msg_q_free_msg (mq, &msg);
+ continue;
+ }
+ svm_msg_q_free_msg (mq, &msg);
+
+ if (PREDICT_FALSE (s->session_state == STATE_CLOSE_ON_EMPTY))
+ return 0;
+ }
+ }
+
+ n_read = svm_fifo_segments (rx_fifo, (svm_fifo_segment_t *) ds);
+ svm_fifo_unset_event (rx_fifo);
+
+ if (is_ct && n_read + svm_fifo_max_dequeue (rx_fifo) == rx_fifo->nitems)
+ {
+ /* If the peer is not polling send notification */
+ if (!svm_fifo_has_event (s->rx_fifo))
+ app_send_io_evt_to_vpp (s->vpp_evt_q, s->rx_fifo,
+ SESSION_IO_EVT_CT_RX, SVM_Q_WAIT);
+ }
+
+ return n_read;
+}
+
+void
+vppcom_session_free_segments (uint32_t session_handle,
+ vppcom_data_segments_t ds)
+{
+ vcl_worker_t *wrk = vcl_worker_get_current ();
+ vcl_session_t *s;
+
+ s = vcl_session_get_w_handle (wrk, session_handle);
+ if (PREDICT_FALSE (!s || s->is_vep))
+ return;
+
+ svm_fifo_segments_free (s->rx_fifo, (svm_fifo_segment_t *) ds);
+}
+