net: tcp: move accept_cb from net_context to net_tcp

net_context is used for more than just TCP contexts.  However,
the accept_cb field is only used for TCP.  Let's move it from
the generic net_context structure to the TCP specific net_tcp
structure.

Change-Id: If923c7aba1355cf5f91c07a7e7e469d385c7c365
Signed-off-by: Michael Scott <michael.scott@linaro.org>

include/net/net_context.h

@@ -106,11 +106,11 @@ typedef void (*net_context_send_cb_t)(struct net_context *context,
  * @param status The status code, 0 on success, < 0 otherwise
  * @param user_data The user data given in net_context_accept() call.
  */
-typedef void (*net_context_accept_cb_t)(struct net_context *new_context,
-					struct sockaddr *addr,
-					socklen_t addrlen,
-					int status,
-					void *user_data);
+typedef void (*net_tcp_accept_cb_t)(struct net_context *new_context,
+				    struct sockaddr *addr,
+				    socklen_t addrlen,
+				    int status,
+				    void *user_data);
 
 struct net_tcp;
 
@@ -164,11 +164,6 @@ struct net_context {
 #if defined(CONFIG_NET_TCP)
 	/** TCP connection information */
 	struct net_tcp *tcp;
-
-	/** Accept callback to be called when the connection has been
-	 * established.
-	 */
-	net_context_accept_cb_t accept_cb;
 #endif /* CONFIG_NET_TCP */
 };
 
@@ -516,7 +511,7 @@ int net_context_connect(struct net_context *context,
  * @return 0 if ok, < 0 if error
  */
 int net_context_accept(struct net_context *context,
-		       net_context_accept_cb_t cb,
+		       net_tcp_accept_cb_t cb,
 		       int32_t timeout,
 		       void *user_data);
 

subsys/net/ip/net_context.c

@@ -1260,7 +1260,7 @@ static enum net_verdict tcp_syn_rcvd(struct net_conn *conn,
 
 		net_tcp_print_recv_info("ACK", buf, NET_TCP_BUF(buf)->src_port);
 
-		if (!context->accept_cb) {
+		if (!context->tcp->accept_cb) {
 			NET_DBG("No accept callback, connection reset.");
 			goto reset;
 		}
@@ -1376,11 +1376,11 @@ static enum net_verdict tcp_syn_rcvd(struct net_conn *conn,
 		new_context->user_data = context->user_data;
 		context->user_data = NULL;
 
-		context->accept_cb(new_context,
-				   &new_context->remote,
-				   addrlen,
-				   0,
-				   new_context->user_data);
+		context->tcp->accept_cb(new_context,
+					&new_context->remote,
+					addrlen,
+					0,
+					new_context->user_data);
 	}
 
 	return NET_DROP;
@@ -1397,7 +1397,7 @@ reset:
 #endif /* CONFIG_NET_TCP */
 
 int net_context_accept(struct net_context *context,
-		       net_context_accept_cb_t cb,
+		       net_tcp_accept_cb_t cb,
 		       int32_t timeout,
 		       void *user_data)
 {
@@ -1486,7 +1486,11 @@ int net_context_accept(struct net_context *context,
 	}
 
 	context->user_data = user_data;
-	context->accept_cb = cb;
+
+	/* accept callback is only valid for TCP contexts */
+	if (net_context_get_ip_proto(context) == IPPROTO_TCP) {
+		context->tcp->accept_cb = cb;
+	}
 #endif /* CONFIG_NET_TCP */
 
 	return 0;

subsys/net/ip/tcp.c

@@ -149,6 +149,8 @@ struct net_tcp *net_tcp_alloc(struct net_context *context)
 	tcp_context[i].send_seq = init_isn();
 	tcp_context[i].recv_max_ack = tcp_context[i].send_seq + 1u;
 
+	tcp_context[i].accept_cb = NULL;
+
 	k_timer_init(&tcp_context[i].retry_timer, tcp_retry_expired, NULL);
 
 	return &tcp_context[i];
@@ -810,12 +812,12 @@ void net_tcp_change_state(struct net_tcp *tcp,
 		tcp->context->conn_handler = NULL;
 	}
 
-	if (tcp->context->accept_cb) {
-		tcp->context->accept_cb(tcp->context,
-					&tcp->context->remote,
-					sizeof(struct sockaddr),
-					-ENETRESET,
-					tcp->context->user_data);
+	if (tcp->accept_cb) {
+		tcp->accept_cb(tcp->context,
+			       &tcp->context->remote,
+			       sizeof(struct sockaddr),
+			       -ENETRESET,
+			       tcp->context->user_data);
 	}
 }
 

subsys/net/ip/tcp.h

@@ -133,6 +133,11 @@ struct net_tcp {
 	uint32_t state : 4;
 	/** Remaining bits in this uint32_t */
 	uint32_t _padding : 15;
+
+	/** Accept callback to be called when the connection has been
+	 * established.
+	 */
+	net_tcp_accept_cb_t accept_cb;
 };
 
 static inline bool net_tcp_is_used(struct net_tcp *tcp)