l2udptest_client: only transmit after receiving a tx_request

impl/src/layer2/connection.c

@@ -84,7 +84,7 @@ void connection_setup_incoming(connection_ctx_t *ctx)
 }
 
 
-result_t connection_handle_packet(connection_ctx_t *ctx, const uint8_t *buf, size_t buf_len, layer2_data_packet_t *data_packet)
+result_t connection_handle_packet(connection_ctx_t *ctx, const uint8_t *buf, size_t buf_len, layer2_data_packet_t *data_packet, bool *tx_req_rcvd)
 {
 	// check the connection state
 	switch(ctx->conn_state) {
@@ -144,7 +144,7 @@ result_t connection_handle_packet(connection_ctx_t *ctx, const uint8_t *buf, siz
 	const uint8_t *payload = buf + header_size;
 	size_t payload_len = packet_size - header_size;
 
-	return connection_handle_packet_prechecked(ctx, &header, payload, payload_len, data_packet);
+	return connection_handle_packet_prechecked(ctx, &header, payload, payload_len, data_packet, tx_req_rcvd);
 }
 
 static result_t handle_conn_mgmt(
@@ -205,7 +205,8 @@ result_t connection_handle_packet_prechecked(
 		connection_ctx_t *ctx,
 		const layer2_packet_header_t *header,
 		const uint8_t *payload, size_t payload_len,
-		layer2_data_packet_t *data_packet)
+		layer2_data_packet_t *data_packet,
+		bool *tx_req_rcvd)
 {
 	data_packet->payload_type = L2_PAYLOAD_TYPE_INVALID;
 	data_packet->payload_len = 0;
@@ -243,11 +244,14 @@ result_t connection_handle_packet_prechecked(
 
 	ctx->last_acked_seq = header->rx_seq_nr;
 
+	*tx_req_rcvd = false;
 
 	switch(header->msg_type) {
 		case L2_MSG_TYPE_EMPTY:
 			LOG(LVL_DEBUG, "Empty packet: accepted ACK for %u.", ctx->last_acked_seq);
 
+			*tx_req_rcvd = header->tx_request;
+
 			// empty packets also reset the timeout timer
 			ctx->last_rx_time = get_hires_time();
 
@@ -263,6 +267,7 @@ result_t connection_handle_packet_prechecked(
 			return OK;
 
 		case L2_MSG_TYPE_DATA:
+			*tx_req_rcvd = header->tx_request;
 			break;
 
 		default:

impl/src/layer2/connection.h

@@ -89,13 +89,15 @@ void connection_setup_incoming(connection_ctx_t *ctx);
  * \param[in]    buf           Pointer to the packet data.
  * \param[in]    buf_len       Length of the packet.
  * \param[out]   data_packet   Structure will be filled with a received data packet.
+ * \param[out]   tx_req_rcvd   Was the tx_request flag set in the decoded packet.
  * \returns           A result code from the packet handling procedure.
  */
 result_t connection_handle_packet(
 		connection_ctx_t *ctx,
 		const uint8_t *buf,
 		size_t buf_len,
-		layer2_data_packet_t *data_packet);
+		layer2_data_packet_t *data_packet,
+		bool *tx_req_rcvd);
 
 /*!\brief Handle a received packet where the header has already been decoded.
  *
@@ -109,13 +111,15 @@ result_t connection_handle_packet(
  * \param[in]    payload       Pointer to the payload data.
  * \param[in]    payload_len   Length of the payload data.
  * \param[out]   data_packet   Structure will be filled with a received data packet.
+ * \param[out]   tx_req_rcvd   Was the tx_request flag set in the decoded packet.
  * \returns           A result code from the packet handling procedure.
  */
 result_t connection_handle_packet_prechecked(
 		connection_ctx_t *ctx,
 		const layer2_packet_header_t *header,
 		const uint8_t *payload, size_t payload_len,
-		layer2_data_packet_t *data_packet);
+		layer2_data_packet_t *data_packet,
+		bool *tx_req_rcvd);
 
 /*!\brief Return the sequence number expected next by our side.
  */

impl/src/layer2/digipeater.c

@@ -158,8 +158,9 @@ result_t digipeater_handle_packet(
 				connection_list_entry_t *head = connection_list_get_head(&ctx->conn_list);
 				if(head) {
 					connection_ctx_t *current_conn = &head->connection;
+					bool tx_request_received = false;
 					result = connection_handle_packet_prechecked(
-							current_conn, &header, payload, payload_len, data_packet);
+							current_conn, &header, payload, payload_len, data_packet, &tx_request_received);
 				} else {
 					LOG(LVL_WARN, "Digipeater in CONN state, but there is no active connection! Packet dropped.");
 					result = OK;

impl/test/layer2_over_udp/l2udptest_client.c

@@ -141,7 +141,8 @@ result_t connect_to_digipeater(connection_ctx_t *conn)
 		}
 
 		layer2_data_packet_t data_packet;
-		result_t err_code = connection_handle_packet(conn, packetbuf, ret, &data_packet);
+		bool tx_request_received = false;
+		result_t err_code = connection_handle_packet(conn, packetbuf, ret, &data_packet, &tx_request_received);
 
 		switch(err_code) {
 			case OK:
@@ -287,14 +288,6 @@ int main(void)
 	RESULT_CHECK(connect_to_digipeater(&l2conn));
 
 	while(m_running) {
-		connection_evt_t evt;
-		RESULT_CHECK(connection_maintain(&l2conn, &evt));
-
-		if(evt == CONN_EVT_TIMEOUT) {
-			LOG(LVL_ERR, "Connection timed out. Shutting down.");
-			break;
-		}
-
 		// fill the TX queue from the TUN device
 		while(connection_can_enqueue_packet(&l2conn)) {
 			int ret = poll(&pfd_tun, 1, 0 /* timeout */);
@@ -376,10 +369,17 @@ int main(void)
 			LOG(LVL_DEBUG, "Burst finished: %zd packets sent.", burst_len);
 		}
 
-		// make sure the receiver runs for a minimum amount of time
-		block_tx_for(TX_SWITCH_BACKOFF_AFTER_RX_ON_MS);
+		bool may_tx = false;
+		while(!may_tx) {
+			connection_evt_t evt;
+			RESULT_CHECK(connection_maintain(&l2conn, &evt));
+
+			if(evt == CONN_EVT_TIMEOUT) {
+				LOG(LVL_ERR, "Connection timed out. Shutting down.");
+				m_running = false;
+				break;
+			}
 
-		while(get_hires_time() < next_tx_switch_time) {
 			// ** Receive signal **
 
 			int ret = poll(&pfd_bcast, 1, 10);
@@ -406,7 +406,9 @@ int main(void)
 
 			layer2_data_packet_t data_packet;
 
-			result_t result = connection_handle_packet(&l2conn, packetbuf, ret, &data_packet);
+			bool tx_request_received = false;
+			result_t result = connection_handle_packet(&l2conn, packetbuf, ret, &data_packet, &tx_request_received);
+			may_tx = may_tx || tx_request_received;
 			switch(result) {
 				case OK:
 					m_rx_stats.successful_decodes++;
@@ -456,6 +458,9 @@ int main(void)
 
 			fprintf(stderr, "r");
 		}
+
+		// give the other side some time to switch to rx
+		sleep_until(next_tx_switch_time);
 	}
 
 	// ** Cleanup **