Connection Problems to a TCP Server

RE: Connection Problems to a TCP Server

Simon — Wed, 20 Nov 2019 00:55:19 GMT

I am glad you were able to make it work and I am happy to help.

Best regards,

Simon

RE: Connection Problems to a TCP Server

Bergmann — Tue, 19 Nov 2019 14:42:17 GMT

I was now able to send data to my TCP server!

Thanks for your help!

RE: Connection Problems to a TCP Server

Calin M — Tue, 19 Nov 2019 04:40:43 GMT

Hi Simon,

That's what I was looking for, thanks!

Calin

RE: Connection Problems to a TCP Server

Simon — Mon, 18 Nov 2019 22:47:05 GMT

Calin M:

I wrote a quick sample earlier that demonstrated how to write AT commands from your code:

devzone.nordicsemi.com/.../at_5F00_commands_5F00_test.zip

Is this what you are looking for? If not, or if you have more questions, could you open a new ticket? Since this question is unrelated to the initial question.

Best regards,

Simon

RE: Connection Problems to a TCP Server

Simon — Mon, 18 Nov 2019 22:39:43 GMT

[quote user="Weidetracker"]Thanks for your big help![/quote]

No problem, I am always happy to help and I am glad it finally worked out.

[quote user="Weidetracker"]So the next step would be to change the connect_to_goolge project so that it connects to my TCP server?[/quote]

Yes, I believe it should be all good now, and that would be the next step yes. If that doesn't work, you know that the issue is not with the code but your TCP server. Take a look at this link, which talks about port forwarding and how to make the server accessible on the web.

Best regards,

Simon

RE: Connection Problems to a TCP Server

Calin M — Mon, 18 Nov 2019 19:31:51 GMT

Hi Simon,

I'm working on something similar, and I'd like to execute the AT commands when the program starts, rather that typing them into the LTE Link Monitor. Is there a code sample for how to do that?

Thanks!

Calin

RE: Connection Problems to a TCP Server

Bergmann — Mon, 18 Nov 2019 19:03:24 GMT

Hey, now I got a connect error: 0

[quote userid="72692" url="~/f/nordic-q-a/53940/connection-problems-to-a-tcp-server/219553"]check that blocking_connect() returns 0)[/quote]

And now I should be connected with the google DNS Server, if I understand this right?

So the next step would be to change the connect_to_goolge project so that it connects to my TCP server?

Thanks for your big help!

RE: Connection Problems to a TCP Server

Simon — Mon, 18 Nov 2019 15:30:55 GMT

[quote user="Weidetracker"][/quote]

Is there a way I can use AT+CFUN? for this program? Because I need to make sure, that

AT%XSYSTEMMODE=0,1,1,0

and that

AT+CGDCONT=0,"IP","m2m.nbiot.t-mobile.at"

You could try to enable the AT Host library:

# AT host library
CONFIG_AT_HOST_LIBRARY=y
CONFIG_UART_INTERRUPT_DRIVEN=y

Then open the LTE Link Monitor and type in the AT commands.

Could you upload a modem trace? Then we can analyze it and find out the reason for the behavior.

Best regards,

Simon

RE: Connection Problems to a TCP Server

Bergmann — Sun, 17 Nov 2019 08:56:55 GMT

No, I still have the problem.

RE: Connection Problems to a TCP Server

Simon — Fri, 15 Nov 2019 11:51:54 GMT

I am sorry for the delay, I've been quite busy lately. Have you been able to resolve the issue?

RE: Connection Problems to a TCP Server

Bergmann — Tue, 12 Nov 2019 14:21:45 GMT

Hi I added

CONFIG_LTE_PDP_CONTEXT="0,\"IP\",\"m2m.nbiot.t-mobile.at\""
CONFIG_LTE_LEGACY_PCO_MODE=y
CONFIG_NRF_CLOUD_STATIC_IPV4=y
CONFIG_LTE_NETWORK_MODE_NBIOT_GPS=y
CONFIG_LTE_NETWORK_MODE_LTE_M_GPS=n

to the prj.conf file. And then i got the error messages:

devzone.nordicsemi.com/.../2019_2D00_11_2D00_12T14_5F00_13_5F00_04.792Z_2D00_log.txt

Is there a way I can use AT+CFUN? for this program? Because I need to make sure, that

AT%XSYSTEMMODE=0,1,1,0

and that

AT+CGDCONT=0,"IP","m2m.nbiot.t-mobile.at"

Otherwise there won't be a connection.

Thanks for your help and your time!

RE: Connection Problems to a TCP Server

Simon — Mon, 11 Nov 2019 21:54:54 GMT

devzone.nordicsemi.com/.../3010.connect_5F00_to_5F00_google.zip

See if you are able to connect with this example (check that blocking_connect() returns 0). It worked on my nRF91 DK.

Best regards,

Simon

RE: Connection Problems to a TCP Server

Bergmann — Thu, 07 Nov 2019 05:36:32 GMT

Ok, i changed the IP address and the port:

#include <errno.h>
#include <stdio.h>
#include <net/bsdlib.h>
#include <kernel.h>
#include <net/socket.h>
#include <at_cmd.h>
#include <lte_lc.h>

#define PORT 80
#define IPADDR "216.58.208.110"

#include <logging/log.h>

/* Initialize module-specific magic state (once per module name): */
LOG_MODULE_REGISTER();

int clientInit()
{
    int fd, ret;
    struct sockaddr_in bind_addr;

    fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (fd < 0) {
        printk("error: socket: %d\n", errno);
        return -1;
    } else {
		printk("Socket successfully created!\n");
	}

    bind_addr.sin_family = AF_INET;
	inet_pton(AF_INET, IPADDR, &bind_addr.sin_addr.s_addr);
    bind_addr.sin_port = htons(PORT);

	if (bind(fd, (struct sockaddr *)&bind_addr, sizeof(bind_addr)) < 0) {
		printf("error: bind: %d\n", errno);
		exit(1);
	}

	ret = connect(fd, (struct sockaddr*)&bind_addr, sizeof(bind_addr));
	if (ret < 0) {
		printk("ERROR CONNECTING RET: %d ERRNO: %d\n", ret, errno);
        return ret;
	}
    return fd;
}

static void modem_configure(void)
{
#if defined(CONFIG_LTE_LINK_CONTROL)
	if (IS_ENABLED(CONFIG_LTE_AUTO_INIT_AND_CONNECT)) {
		/* Do nothing, modem is already turned on
		 * and connected.
		 */
	} else {
		int err;

		printk("LTE Link Connecting ...\n");
		err = lte_lc_init_and_connect();
		__ASSERT(err == 0, "LTE link could not be established.");
		printk("LTE Link Connected!\n");
	}
#endif
}

int main(void) {

    printk("Modem Configure\n");
    modem_configure();

    int fd = clientInit();
    if (fd < 0) {
        printk("Client Init err %d\n", fd);
        return fd;
    }

    char buf[] = "Hallo Welt!\n";

    int out_len = send(fd, buf, sizeof(buf), 0);
    if (out_len < 0) {
        printk("error: send: %d\n", errno);
    }

	while (1) {
		k_sleep(500);
        printk("Waiting...\n");
	}
}

And then I flashed the code to the nRF9160, but there is the same error again:

devzone.nordicsemi.com/.../2019_2D00_11_2D00_07T05_5F00_19_5F00_34.270Z_2D00_log.txt

Does that mean, that the code should be ok, if it works at your location?

Might there be some problems with the Sim Card? I already tested it with another Board from my local provider (Board: SARA AFF N211). He provided a tutorial for that and that worked fine to connect to his IoT Gateway Server with another APN.

By the way, I never got into nRF Cloud. I also have connection problems there, but I couldn’t fix them yet: devzone.nordicsemi.com/.../nrf9160-dk-connecting-problems-with-nrf-cloud So I tried to set up the connection directly to the TCP Server (what would be the final goal) and skip the connection process to nRF Cloud.

What do you think about this problem, do you have any further ideas?

Thanks for your answers and your help!

RE: Connection Problems to a TCP Server

Simon — Wed, 06 Nov 2019 15:21:11 GMT

I modified your example, by changing the IP address to 216.58.208.110 (IP address of google.com) and the port to 80, and I was able to connect successfully. Are you sure your server is exposed to the public internet? Try creating a client with SocketTest and connect to the server.

Check out this thread as well, which may help you.

Best regards,

Simon

RE: Connection Problems to a TCP Server

Bergmann — Tue, 05 Nov 2019 15:09:29 GMT

Hi, i tried it with this code now:

#include <errno.h>
#include <stdio.h>
#include <net/bsdlib.h>
#include <kernel.h>
#include <net/socket.h>
#include <at_cmd.h>
#include <lte_lc.h>

#define PORT 22
#define IPADDR "8.8.8.8"

#include <logging/log.h>

/* Initialize module-specific magic state (once per module name): */
LOG_MODULE_REGISTER();

int clientInit()
{
    int fd, ret;
    struct sockaddr_in bind_addr;

    fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (fd < 0) {
        printk("error: socket: %d\n", errno);
        return -1;
    } else {
		printk("Socket successfully created!\n");
	}

    bind_addr.sin_family = AF_INET;
	inet_pton(AF_INET, IPADDR, &bind_addr.sin_addr.s_addr);
    bind_addr.sin_port = htons(PORT);

	if (bind(fd, (struct sockaddr *)&bind_addr, sizeof(bind_addr)) < 0) {
		printf("error: bind: %d\n", errno);
		exit(1);
	}

	ret = connect(fd, (struct sockaddr*)&bind_addr, sizeof(bind_addr));
	if (ret < 0) {
		printk("ERROR CONNECTING RET: %d ERRNO: %d\n", ret, errno);
        return ret;
	}
    return fd;
}

static void modem_configure(void)
{
#if defined(CONFIG_LTE_LINK_CONTROL)
	if (IS_ENABLED(CONFIG_LTE_AUTO_INIT_AND_CONNECT)) {
		/* Do nothing, modem is already turned on
		 * and connected.
		 */
	} else {
		int err;

		printk("LTE Link Connecting ...\n");
		err = lte_lc_init_and_connect();
		__ASSERT(err == 0, "LTE link could not be established.");
		printk("LTE Link Connected!\n");
	}
#endif
}

int main(void) {

    printk("Modem Configure\n");
    modem_configure();

    int fd = clientInit();
    if (fd < 0) {
        printk("Client Init err %d\n", fd);
        return fd;
    }

    char buf[] = "Hallo Welt!\n";

    int out_len = send(fd, buf, sizeof(buf), 0);
    if (out_len < 0) {
        printk("error: send: %d\n", errno);
    }

	while (1) {
		k_sleep(500);
        printk("Waiting...\n");
	}
}

But I still get an error like this:

devzone.nordicsemi.com/.../2019_2D00_11_2D00_05T14_5F00_58_5F00_52.883Z_2D00_log.txt

I really would appreciate it, if you could take a closer look/ask somebody with more knowledge, because I am out of ideas on what could be the cause of the issue.

Thanks for your time and your help!

RE: Connection Problems to a TCP Server

Simon — Mon, 04 Nov 2019 13:52:22 GMT

I don't have full knowledge about this, but don't you need to bind the file descriptor with the address using bind() ( between socket() and connect())? Try this and see if it works then.

If you still have problems, I will take a closer look at your issue/ask somebody with more knowledge about it.

Best regards,

Simon