layer2: Remove event callbacks

Instead, connection and digipeater now update a event code passed by reference
to the maintain() function. This was the only place where the callback was
called before.

Minor side effect: maintain must be called multiple times if multiple events
trigger at the same time.

impl/src/layer2/connection.c

@@ -18,9 +18,7 @@
 result_t connection_init(
 		connection_ctx_t *ctx,
 		const ham64_t *my_addr,
-		const ham64_t *peer_addr,
-		connection_event_callback_t event_cb,
-		void *user_ctx)
+		const ham64_t *peer_addr)
 {
 	ctx->last_acked_seq = 0;
 	ctx->next_expected_seq = 0;
@@ -32,14 +30,10 @@ result_t connection_init(
 	ctx->my_addr = *my_addr;
 	ctx->peer_addr = *peer_addr;
 
-	ctx->event_cb = event_cb;
-
 	uint64_t now = get_hires_time();
 	ctx->last_rx_time = now;
 	ctx->retransmit_time = 0;
 
-	ctx->user_context = user_ctx;
-
 	// calculate IPv6 address
 	struct in6_addr net_addr;
 	inet_pton(AF_INET6, IPV6_NET, &net_addr);
@@ -518,14 +512,14 @@ bool connection_is_closed(const connection_ctx_t *ctx)
 }
 
 
-result_t connection_maintain(connection_ctx_t *ctx)
+result_t connection_maintain(connection_ctx_t *ctx, connection_evt_t *evt)
 {
 	uint64_t now = get_hires_time();
 
 	if(now > ctx->last_rx_time + HRTIME_MS(CONNECTION_TIMEOUT_MS)) {
 		LOG(LVL_INFO, "Connection timed out.");
 		ctx->conn_state = CONN_STATE_CLOSED;
-		ctx->event_cb(ctx, CONN_EVT_TIMEOUT, ctx->user_context);
+		*evt = CONN_EVT_TIMEOUT;
 		return OK;
 	}
 
@@ -533,7 +527,8 @@ result_t connection_maintain(connection_ctx_t *ctx)
 		LOG(LVL_INFO, "Retransmit triggered.");
 		ctx->retransmit_time = 0;
 		connection_restart_tx(ctx);
-		ctx->event_cb(ctx, CONN_EVT_RETRANSMIT, ctx->user_context);
+		*evt = CONN_EVT_RETRANSMIT;
+		return OK;
 	}
 
 	return OK;

impl/src/layer2/connection.h

@@ -27,18 +27,14 @@ typedef enum {
 } connection_state_t;
 
 typedef enum {
+	CONN_EVT_NONE,       //!< No event has occurred
 	CONN_EVT_TIMEOUT,    //!< The connection timed out because no packets were received
 	CONN_EVT_RETRANSMIT, //!< Packet queue transmission is restarted
 } connection_evt_t;
 
-/*!\brief Type for a callback function that is called on various connection events. */
-typedef void (*connection_event_callback_t)(struct connection_ctx_s *conn, connection_evt_t evt, void *user_ctx);
-
 typedef struct connection_ctx_s {
 	connection_state_t conn_state; //!< State of the connection.
 
-	connection_event_callback_t event_cb; //!< Callback function for event signalling.
-
 	ham64_t my_addr;             //!< The local link layer address.
 	ham64_t peer_addr;           //!< The link layer address of the peer.
 
@@ -54,8 +50,6 @@ typedef struct connection_ctx_s {
 
 	uint64_t retransmit_time;    //!< Time when a retransmit shall be triggered.
 	uint64_t last_rx_time;       //!< Time when a packet was last received and decoded.
-
-	void *user_context;          //!< An arbitrary pointer that can set by the user.
 } connection_ctx_t;
 
 
@@ -64,16 +58,12 @@ typedef struct connection_ctx_s {
  * \param ctx       The connection context to initialize.
  * \param my_addr   The local link layer address.
  * \param peer_addr The remote link layer address.
- * \param event_cb  Callback for connection events.
- * \param user_ctx  User context pointer (for arbitrary data).
  * \returns OK if everything worked or a fitting error code.
  */
 result_t connection_init(
 		connection_ctx_t *ctx,
 		const ham64_t *my_addr,
-		const ham64_t *peer_addr,
-		connection_event_callback_t event_cb,
-		void *user_ctx);
+		const ham64_t *peer_addr);
 
 /*!\brief Destroy the given layer 2 connection context.
  */
@@ -189,8 +179,11 @@ bool connection_is_closed(const connection_ctx_t *ctx);
 /*!\brief Handle internal maintenance tasks.
  *
  * This should be called periodically to handle timeouts and retransmissions.
+ *
+ * \param ctx[in]   The connection context.
+ * \param evt[out]  Set to an event that occurred, or CONN_EVT_NONE.
  */
-result_t connection_maintain(connection_ctx_t *ctx);
+result_t connection_maintain(connection_ctx_t *ctx, connection_evt_t *evt);
 
 /*!\brief Check if the given IPv6 peer address belongs to this connection.
  *

impl/src/layer2/digipeater.c

@@ -17,23 +17,6 @@
 #include "results.h"
 #include "utils.h"
 
-void conn_event_cb(struct connection_ctx_s *conn, connection_evt_t evt, void *user_ctx)
-{
-	(void)conn;
-	digipeater_ctx_t *digi_ctx = user_ctx;
-
-	switch(evt) {
-		case CONN_EVT_TIMEOUT:
-			// connection has been closed by timeout -> clean up the list
-			connection_list_delete_closed(&digi_ctx->conn_list);
-			break;
-
-		default:
-			// do nothing
-			break;
-	}
-}
-
 static result_t digipeater_handle_beacon_responses(digipeater_ctx_t *ctx, const layer2_packet_header_t *header, const uint8_t *buf, size_t buf_len)
 {
 	LOG(LVL_DEBUG, "Handling beacon response packet.");
@@ -60,7 +43,7 @@ static result_t digipeater_handle_beacon_responses(digipeater_ctx_t *ctx, const
 	// and add it at the beginning of the connection list.
 
 	connection_ctx_t new_conn;
-	ERR_CHECK(connection_init(&new_conn, &ctx->my_addr, &header->src_addr, conn_event_cb, ctx));
+	ERR_CHECK(connection_init(&new_conn, &ctx->my_addr, &header->src_addr));
 
 	ERR_CHECK(connection_send_parameters(&new_conn));
 
@@ -369,7 +352,19 @@ result_t digipeater_maintain(digipeater_ctx_t *ctx)
 					LOG(LVL_INFO, "No active connection -> force beacon state for packet handling.");
 					ctx->state = DIGIPEATER_STATE_BEACON;
 				} else {
-					ERR_CHECK(connection_maintain(&head->connection));
+					connection_evt_t evt;
+					ERR_CHECK(connection_maintain(&head->connection, &evt));
+
+					switch(evt) {
+						case CONN_EVT_TIMEOUT:
+							// connection has been closed by timeout -> clean up the list
+							connection_list_delete_closed(&ctx->conn_list);
+							break;
+
+						default:
+							// do nothing
+							break;
+					}
 				}
 				break;
 			}

impl/src/layer2/digipeater.h

@@ -26,14 +26,9 @@ typedef enum {
 	DIGIPEATER_EVT_INTERVAL_END, //!< The current cycle has ended and new packets should be transmitted.
 } digipeater_evt_t;
 
-/*!\brief Type for a callback function that is called when certain events occur. */
-typedef void (*digipeater_evt_callback_t)(struct digipeater_ctx_s *digi, digipeater_evt_t evt);
-
 typedef struct digipeater_ctx_s {
 	digipeater_state_t state; //!< Current operating state
 
-	digipeater_evt_callback_t event_cb; //!< Callback function for events.
-
 	ham64_t my_addr;             //!< The local link layer address.
 
 	packet_queue_t oneshot_queue; //!< Queue for packets that are sent once and connection-independent

impl/test/layer2_over_udp/l2udptest_client.c

@@ -161,7 +161,7 @@ int main(int argc, char **argv)
 	ham64_t my_address, peer_address;
 	ham64_encode(MY_CALL, &my_address);
 	ham64_encode(PEER_CALL, &peer_address);
-	RESULT_CHECK(connection_init(&l2conn, &my_address, &peer_address, conn_evt_cb, NULL));
+	RESULT_CHECK(connection_init(&l2conn, &my_address, &peer_address));
 
 	// force connection into the established state
 	l2conn.conn_state = CONN_STATE_ESTABLISHED;
@@ -232,7 +232,13 @@ int main(int argc, char **argv)
 	while(m_running) {
 		uint64_t now = get_hires_time();
 
-		RESULT_CHECK(connection_maintain(&l2conn));
+		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)) {