[tcp/ip stack] lwip - cannot connect()

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[tcp/ip stack] lwip - cannot connect()

Contributor III

I need to implement a TCP client for a MQTT application with freeRTOS. I need to implement functions that send and receive data over TCP. Unfortunately, the connect() function doesn't work. I am using MPC5748G and lwip for TCP/IP stack.

I tried using bothe the netconn API (netconn_connect), as well as socket API - both of them freeze in sys_arch_sem_wait() on the LWIP_ASSERT("sem != NULL", sem != NULL);

Strangely UDP communication and other TCP functionality is correct: the netconn_listen(), netconn_accept(), and others work fine. Only the netconn_connect() makes the board freeze.

my code:

int TCPClientSendTest(){
	struct sockaddr_in client_address;
	struct sockaddr_in server_address;
	int cfd;
	socklen_t client_address_len;
	char welcome_msg[] = "\nClient sends a message" ;

	if ( (cfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ) { return -1; }

	client_address.sin_addr.s_addr = inet_addr("");
	client_address.sin_family = AF_INET;
	client_address.sin_port = htons(SRC_PORT_NUM);
	if(bind(cfd, (struct sockaddr *) &client_address, sizeof(client_address))< 0){ return -2;	}

	server_address.sin_addr.s_addr = inet_addr("");
	server_address.sin_port = htons(DST_PORT_NUM);
	server_address.sin_family = AF_INET;
	if ( (connect(cfd,(struct sockaddr *) &server_address, sizeof(server_address))) < 0 ) { return -3;} //DOESN'T WORK! BOARD FREEZES

	if ((send(cfd, (const char *)welcome_msg, strlen(welcome_msg)+1,0)) < 0){ return -4; 	}

	return 0;


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2 Replies

Contributor IV

Did you ever figure this out?  I'm seeing the exact same issue.

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Contributor II

Hi, I am facing the same issue. The netconn_connect(); function doesn't show any return value. Do you have any luck?

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