Operation not supported (95) when using NRF52

[estnisk]

Hi,

I am interested in using a pair of NRF52840 USB dongles to communicate on the L2CAP layer. I have flashed the dongles with the Zephyr's hci_usb samples, and have been able to connect the dongles with bluetoothctl. Now, I want to do the same using the socket functionality to use the L2CAP communication layer, however, I am receiving strerror EOPNOTSUPP (95): "Operation not supported", when using client-side connect() from sys/socket.h. I'm afraid I'm doing something conceptually wrong, but I also get the exact same error when trying hci_inquiry() from bluetooth/l2cap.h

Code example:

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#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <sys/socket.h>

#include <bluetooth/bluetooth.h>

#include <bluetooth/l2cap.h>

#include <errno.h>

extern int errno ;

int main(void)

{

struct sockaddr_l2 addr = { 0 };

int s, status;

char *message = "hello!";

char dest[18] = "ED:67:8A:54:94:40";

// allocate a socket

s = socket(AF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);

// set the connection parameters (who to connect to)

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/l2cap.h>
#include <errno.h>

extern int errno ;

int main(void)
{
    struct sockaddr_l2 addr = { 0 };
    int s, status;
    char *message = "hello!";
    char dest[18] = "ED:67:8A:54:94:40";

    // allocate a socket
    s = socket(AF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);

    // set the connection parameters (who to connect to)
    addr.l2_family = PF_BLUETOOTH;
    addr.l2_psm = htobs(0x1001);
    str2ba( dest, &addr.l2_bdaddr );

    // connect to server
    status = connect(s, (struct sockaddr *)&addr, sizeof(addr));

    // send a message
    if( status == 0 ) {
        status = write(s, "hello!", 6);
    }

    int errnum = errno;
    if( status < 0 ) perror("uh oh");
    if( status < 0 ) fprintf(stderr, "Error number: %d\n", errno);

    close(s);
}

Some more info:

1) This isn't likely because I don't have a server-side listening since I get the same error with a different example using hci_inquiry() for scanning nearby devices.

2) The code reports "No route to host" (113) when unplugging the dongle.

3) Tried this code with NRF52_PCA10040 with hci_uart sample running.

4) Tried manually changing the default 00:00:00:00:00:00 address to something else.

5) Socket gets allocated properly

Hope you can help!