L2CAP Bluetooth: message too long

[OBaselga]

Hi everyone,

I want to send messages with L2CAP protocol between two Bluetooth devices. This is my client code:

void process_bluetooth () {
 
    int bl_buff_it = 0; // global buffer iterator
 
    // Code of: https://people.csail.mit.edu/albert/bluez-intro/x559.html
    struct sockaddr_l2 addr = { 0 };
    int s, status;
    char dest[18] = "24:0A:64:28:71:E6";
 
    // Socket creation
    s = socket(AF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);
 
    // Connection parameters
    addr.l2_family = AF_BLUETOOTH;
    addr.l2_psm = htobs(0x1001);
    str2ba( dest, &addr.l2_bdaddr );
 
    // Establishing connection
    status = connect(s, (struct sockaddr *)&addr, sizeof(addr));
    if (status < 0) exit(0);
 
    // Message buffer
    int tam_bluetooth_buff = DATA_BLUETOOTH_BUFFER * (SIZE_DATA + 1); // DATA_BLUETOOTH_BUFFER = 128, SIZE_DATA = 3
    char bluetooth_buff[tam_bluetooth_buff];
 
    strcpy(bluetooth_buff, "");
 
    int msg_to_send = 15, msg_num = 0;
    
    char value_string[SIZE_DATA];
 
    while (msg_num < msg_to_send) {
 
        // Checking if data available in global data buffer
        if (bl_check_buff[bl_buff_it] == '1') {
 
            bl_check_buff[bl_buff_it] = '0';
 
            // Add data to buffer
            sprintf(value_string, "%u%u%u ", bl_data_buff[bl_buff_it].bytes[0], bl_data_buff[bl_buff_it].bytes[1], bl_data_buff[bl_buff_it].bytes[2]); // uint8_t bytes[3]
            strcat(bluetooth_buff, value_string);
 
            bl_buff_it = (bl_buff_it + 1) % NUM_ELEMENTS; // NUM_ELEMENTS = huge number
 
            if (bl_buff_it % DATA_BLUETOOTH_BUFFER == 0 && bl_buff_it != 0) {
 
                // Message sending
                if(write(s, bluetooth_buff, tam_bluetooth_buff) < 0) {
                    int errnum = errno;
                    fprintf(stderr, "Value of errno: %d\n", errno);
                    perror("Error printed by perror");
                    fprintf(stderr, "Error opening file: %s\n", strerror( errnum ));
                    exit(0);    
                }
                msg_num++;
 
                strcpy(bluetooth_buff, "");
            }
        }
    }
 
    close(s);
}

My server code is exactly the same as appears in https://people.csail.mit.edu/albert/bluez-intro/x559.html , but buffer size is 65535.

When I try to increase bluetooth_buff 's length - tam_bluetooth_buff variable - I get this error:

Value of errno: 90
Error printed by perror: Message too long
Error opening file: Message too long

Note that everything is working fine if DATA_BLUETOOTH_BUFFER is 128 and not if is 256, for example.

Please help!!

Regards