static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
                                                   unsigned char *buf,
                                                   size_t *olen )
{
    unsigned char *p = buf;
    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;

    *olen = 0;

    MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_point_formats extension" ) );

    if( end < p || (size_t)( end - p ) < 6 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
        return;
    }

    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS      ) & 0xFF );

    *p++ = 0x00;
    *p++ = 2;

    *p++ = 1;
    *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;

    *olen = 6;
}
static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
                                                   unsigned char *buf,
                                                   size_t *olen )
{
    unsigned char *p = buf;
    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;

    *olen = 0;

    MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_point_formats extension" ) );

    if( end < p || (size_t)( end - p ) < 6 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
        return;
    }

    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS      ) & 0xFF );

    *p++ = 0x00;
    *p++ = 2;

    *p++ = 1;
    *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;

    *olen = 6;
}