Hi DanielGruber,

Thanks for the detailed report for wolfMQTT and multithreading. I will see if I can reproduce and resolve.

David Garske, wolfSSL

Hi yighax2,

Check out our wolfssl-examples repo. We have a few examples that will help you with this:

https://github.com/wolfSSL/wolfssl-exam … -callbacks
https://github.com/wolfSSL/wolfssl-exam … master/tls
See the "-callback" TLS examples

These use our custom IO callbacks, which are set using:
wolfSSL_CTX_SetIORecv(ctx, my_IORecv);
wolfSSL_CTX_SetIOSend(ctx, my_IOSend);

You can also set a custom pointer context using:
wolfSSL_SetIOReadCtx(ssl, &recvCtx);
wolfSSL_SetIOWriteCtx(ssl, &sendCtx);

You can build with `WOLFSSL_USER_IO` to disable the internal "socket" handling and require use of these IO callbacks.

Thanks,
David Garske, wolfSSL

Hi pbreed,

Thanks for the forum question. You can also use our support@wolfssl.com ZenDesk system for faster responses.

Can you describe how you are building wolfSSL? Internally we have mutex protection if threading is enabled.

If the --enable-singlethreaded option is set or SINGLE_THREADED is defined then threading is not supported.

Thanks,
David Garske, wolfSSL

Hi burakkirazli,

It depends on the algorithms enabled/used and the FP_MAX_BITS you have defined. The ECC and RSA algorithms use fast math.

Typically during a TLS connection you'll have several of these on the stack. I recommend starting with 10KB of stack and then looking at your stack high watermark to determine how much to reduce.

For RSA the FP_MAX_BITS is double the maximum key size. For RSA 2048-bit requires double max bits so 4096. If you have just ECC defined than FP_MAX_BITS can be ECC max key size + 32. For both RSA and ECC you can reduce ECC stack usage by defining ALT_ECC_SIZE, which will use heap for the ECC point instead of stack.

We have some good examples for configuration the math library cases here:
https://github.com/wolfSSL/wolfssl/blob … settings.h

Thanks,
David Garske, wolfSSL

Hi burakkirazli,

Error -142 is `ASN_GETINT_E`. Happening on call to `wc_RsaPublicKeyDecode`. My best guess is you heap allocation failed when trying to parse the RSA certificate from the peer. Check your heap space and either make more available or switch to a stack based math by defining USE_FAST_MATH. It might be helpful to look at this example user_settings.h file, which describes many build options. https://github.com/wolfSSL/wolfssl/blob … settings.h

Thanks,
David Garske, wolfSSL

Hi burakkirazli,

Looks like the TLS server did not like something in the client_hello and sent back an alert 40 (handshake_failure). Can you describe more about the server and what build options you are using? Perhaps you can send a Wireshark trace and print a run-time list of enabled cipher suites?

#ifndef WOLFSSL_CIPHER_LIST_MAX_SIZE
    #define WOLFSSL_CIPHER_LIST_MAX_SIZE 4096
#endif
static void ShowCiphers(void)
{
    char ciphers[WOLFSSL_CIPHER_LIST_MAX_SIZE];
    int ret = wolfSSL_get_ciphers(ciphers, (int)sizeof(ciphers));

    if (ret == WOLFSSL_SUCCESS)
        printf("%s\n", ciphers);
}

Thanks,
David Garske, wolfSSL

Hi burakkirazli,

If you don't have socket error codes for EWOULDBLOCK or EAGAIN then why are you using the WOLFMQTT_NONBLOCK build option?

Perhaps can explain more about your use case and socket library being used?

Thanks,
David Garske, wolfSSL

Hi burakkirazli,

You must run the example from the wolfssl-root like:
./examples/echoserver/echoserver

Also you can find some simple TLS examples in our wolfssl-examples repo here:
https://github.com/wolfSSL/wolfssl-examples

Thanks,
David Garske, wolfSSL

Hi JMG,

You can find the RISC-V examples here:
https://github.com/wolfSSL/wolfssl/tree … PSE/SIFIVE
https://github.com/wolfSSL/wolfssl/tree … /IDE/RISCV

Also I just put up a PR to consolidate the RISC-V information into IDE/RISCV here:
https://github.com/wolfSSL/wolfssl/pull/2490

Thanks,
David Garske, wolfSSL

Hi kvhekale,

Try using something like this:

export WOLFSSL_PREFIX="`pwd`/../build"
./configure \
    --host=arm-none-eabi \
    CFLAGS="-mcpu=cortex-m0 --specs=nano.specs -DNO_WOLFSSL_DIR -DWOLFSSL_USER_IO -DNO_WRITEV" \
    --prefix=$WOLFSSL_PREFIX/wolfssl-m0-baremetal \
    --disable-examples
make
make install

Thanks,
David Garske, wolfSSL

Hi Naveen,

By default we have threading support enabled and defaults to pthread. You can define NO_FILESYSTEM to disable it.

I recommend setting up your own build configuration file called "user_settings.h" and defining a single global pre-processor macro WOLFSSL_USER_SETTINGS. Then you can manage all your build settings in one place. In your user application make sure you include wolfssl/wolfcrypt/settings.h before any other wolf headers. We have a section on this in the FAQ link previously sent.

Thanks,
David Garske, wolfSSL

Hi EricDOS,

For measuring sizes of shared objects you might try the size command:

./configure --enable-leantls && make
size ./src/.libs/libwolfssl.dylib
__TEXT    __DATA    __OBJC    others    dec    hex
262144    4096    0    36864    303104    4a000

Thanks,
David Garske, wolfSSL