Ejemplo n.º 1
0
/* Get TLS version string
 */
char *tls_version_string(mbedtls_ssl_context *context) {
	return (char*)mbedtls_ssl_get_version(context);
}
Ejemplo n.º 2
0
int SSLContext::getVersion(State & state, SSLContextData * ssl_context_data) {
    Stack * stack = state.stack;
    stack->push<const std::string &>(mbedtls_ssl_get_version(ssl_context_data->context));
    return 1;
}
Ejemplo n.º 3
0
IoT_Error_t iot_tls_connect(Network *pNetwork, TLSConnectParams *params) {
    int ret = SUCCESS;
    TLSDataParams *tlsDataParams = NULL;
    char portBuffer[6];
    char info_buf[256];

    if(NULL == pNetwork) {
        return NULL_VALUE_ERROR;
    }

    if(NULL != params) {
        _iot_tls_set_connect_params(pNetwork, params->pRootCALocation, params->pDeviceCertLocation,
                                    params->pDevicePrivateKeyLocation, params->pDestinationURL,
                                    params->DestinationPort, params->timeout_ms, params->ServerVerificationFlag);
    }

    tlsDataParams = &(pNetwork->tlsDataParams);

    mbedtls_net_init(&(tlsDataParams->server_fd));
    mbedtls_ssl_init(&(tlsDataParams->ssl));
    mbedtls_ssl_config_init(&(tlsDataParams->conf));

#ifdef CONFIG_MBEDTLS_DEBUG
    mbedtls_esp_enable_debug_log(&(tlsDataParams->conf), 4);
#endif

    mbedtls_ctr_drbg_init(&(tlsDataParams->ctr_drbg));
    mbedtls_x509_crt_init(&(tlsDataParams->cacert));
    mbedtls_x509_crt_init(&(tlsDataParams->clicert));
    mbedtls_pk_init(&(tlsDataParams->pkey));

    ESP_LOGD(TAG, "Seeding the random number generator...");
    mbedtls_entropy_init(&(tlsDataParams->entropy));
    if((ret = mbedtls_ctr_drbg_seed(&(tlsDataParams->ctr_drbg), mbedtls_entropy_func, &(tlsDataParams->entropy),
                                    (const unsigned char *) TAG, strlen(TAG))) != 0) {
        ESP_LOGE(TAG, "failed! mbedtls_ctr_drbg_seed returned -0x%x", -ret);
        return NETWORK_MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED;
    }

   /*  Load root CA...

       Certs/keys can be paths or they can be raw data. These use a
       very basic heuristic: if the cert starts with '/' then it's a
       path, if it's longer than this then it's raw cert data (PEM or DER,
       neither of which can start with a slash. */
    if (pNetwork->tlsConnectParams.pRootCALocation[0] == '/') {
        ESP_LOGD(TAG, "Loading CA root certificate from file ...");
        ret = mbedtls_x509_crt_parse_file(&(tlsDataParams->cacert), pNetwork->tlsConnectParams.pRootCALocation);
    } else {
        ESP_LOGD(TAG, "Loading embedded CA root certificate ...");
        ret = mbedtls_x509_crt_parse(&(tlsDataParams->cacert), (const unsigned char *)pNetwork->tlsConnectParams.pRootCALocation,
                                 strlen(pNetwork->tlsConnectParams.pRootCALocation)+1);
    }

    if(ret < 0) {
        ESP_LOGE(TAG, "failed!  mbedtls_x509_crt_parse returned -0x%x while parsing root cert", -ret);
        return NETWORK_X509_ROOT_CRT_PARSE_ERROR;
    }
    ESP_LOGD(TAG, "ok (%d skipped)", ret);

    /* Load client certificate... */
    if (pNetwork->tlsConnectParams.pDeviceCertLocation[0] == '/') {
        ESP_LOGD(TAG, "Loading client cert from file...");
        ret = mbedtls_x509_crt_parse_file(&(tlsDataParams->clicert),
                                          pNetwork->tlsConnectParams.pDeviceCertLocation);
    } else {
        ESP_LOGD(TAG, "Loading embedded client certificate...");
        ret = mbedtls_x509_crt_parse(&(tlsDataParams->clicert),
                                     (const unsigned char *)pNetwork->tlsConnectParams.pDeviceCertLocation,
                                     strlen(pNetwork->tlsConnectParams.pDeviceCertLocation)+1);
    }
    if(ret != 0) {
        ESP_LOGE(TAG, "failed!  mbedtls_x509_crt_parse returned -0x%x while parsing device cert", -ret);
        return NETWORK_X509_DEVICE_CRT_PARSE_ERROR;
    }

    /* Parse client private key... */
    if (pNetwork->tlsConnectParams.pDevicePrivateKeyLocation[0] == '/') {
        ESP_LOGD(TAG, "Loading client private key from file...");
        ret = mbedtls_pk_parse_keyfile(&(tlsDataParams->pkey),
                                       pNetwork->tlsConnectParams.pDevicePrivateKeyLocation,
                                       "");
    } else {
        ESP_LOGD(TAG, "Loading embedded client private key...");
        ret = mbedtls_pk_parse_key(&(tlsDataParams->pkey),
                                   (const unsigned char *)pNetwork->tlsConnectParams.pDevicePrivateKeyLocation,
                                   strlen(pNetwork->tlsConnectParams.pDevicePrivateKeyLocation)+1,
                                   (const unsigned char *)"", 0);
    }
    if(ret != 0) {
        ESP_LOGE(TAG, "failed!  mbedtls_pk_parse_key returned -0x%x while parsing private key", -ret);
        return NETWORK_PK_PRIVATE_KEY_PARSE_ERROR;
    }

    /* Done parsing certs */
    ESP_LOGD(TAG, "ok");
    snprintf(portBuffer, 6, "%d", pNetwork->tlsConnectParams.DestinationPort);
    ESP_LOGD(TAG, "Connecting to %s/%s...", pNetwork->tlsConnectParams.pDestinationURL, portBuffer);
    if((ret = mbedtls_net_connect(&(tlsDataParams->server_fd), pNetwork->tlsConnectParams.pDestinationURL,
                                  portBuffer, MBEDTLS_NET_PROTO_TCP)) != 0) {
        ESP_LOGE(TAG, "failed! mbedtls_net_connect returned -0x%x", -ret);
        switch(ret) {
            case MBEDTLS_ERR_NET_SOCKET_FAILED:
                return NETWORK_ERR_NET_SOCKET_FAILED;
            case MBEDTLS_ERR_NET_UNKNOWN_HOST:
                return NETWORK_ERR_NET_UNKNOWN_HOST;
            case MBEDTLS_ERR_NET_CONNECT_FAILED:
            default:
                return NETWORK_ERR_NET_CONNECT_FAILED;
        };
    }

    ret = mbedtls_net_set_block(&(tlsDataParams->server_fd));
    if(ret != 0) {
        ESP_LOGE(TAG, "failed! net_set_(non)block() returned -0x%x", -ret);
        return SSL_CONNECTION_ERROR;
    } ESP_LOGD(TAG, "ok");

    ESP_LOGD(TAG, "Setting up the SSL/TLS structure...");
    if((ret = mbedtls_ssl_config_defaults(&(tlsDataParams->conf), MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM,
                                          MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
        ESP_LOGE(TAG, "failed! mbedtls_ssl_config_defaults returned -0x%x", -ret);
        return SSL_CONNECTION_ERROR;
    }

    mbedtls_ssl_conf_verify(&(tlsDataParams->conf), _iot_tls_verify_cert, NULL);

    if(pNetwork->tlsConnectParams.ServerVerificationFlag == true) {
        mbedtls_ssl_conf_authmode(&(tlsDataParams->conf), MBEDTLS_SSL_VERIFY_REQUIRED);
    } else {
        mbedtls_ssl_conf_authmode(&(tlsDataParams->conf), MBEDTLS_SSL_VERIFY_OPTIONAL);
    }
    mbedtls_ssl_conf_rng(&(tlsDataParams->conf), mbedtls_ctr_drbg_random, &(tlsDataParams->ctr_drbg));

    mbedtls_ssl_conf_ca_chain(&(tlsDataParams->conf), &(tlsDataParams->cacert), NULL);
    ret = mbedtls_ssl_conf_own_cert(&(tlsDataParams->conf), &(tlsDataParams->clicert), &(tlsDataParams->pkey));
    if(ret != 0) {
        ESP_LOGE(TAG, "failed! mbedtls_ssl_conf_own_cert returned %d", ret);
        return SSL_CONNECTION_ERROR;
    }

    mbedtls_ssl_conf_read_timeout(&(tlsDataParams->conf), pNetwork->tlsConnectParams.timeout_ms);

#ifdef CONFIG_MBEDTLS_SSL_ALPN
    /* Use the AWS IoT ALPN extension for MQTT, if port 443 is requested */
    if (pNetwork->tlsConnectParams.DestinationPort == 443) {
        const char *alpnProtocols[] = { "x-amzn-mqtt-ca", NULL };
        if ((ret = mbedtls_ssl_conf_alpn_protocols(&(tlsDataParams->conf), alpnProtocols)) != 0) {
            ESP_LOGE(TAG, "failed! mbedtls_ssl_conf_alpn_protocols returned -0x%x", -ret);
            return SSL_CONNECTION_ERROR;
        }
    }
#endif

    if((ret = mbedtls_ssl_setup(&(tlsDataParams->ssl), &(tlsDataParams->conf))) != 0) {
        ESP_LOGE(TAG, "failed! mbedtls_ssl_setup returned -0x%x", -ret);
        return SSL_CONNECTION_ERROR;
    }
    if((ret = mbedtls_ssl_set_hostname(&(tlsDataParams->ssl), pNetwork->tlsConnectParams.pDestinationURL)) != 0) {
        ESP_LOGE(TAG, "failed! mbedtls_ssl_set_hostname returned %d", ret);
        return SSL_CONNECTION_ERROR;
    }
    ESP_LOGD(TAG, "SSL state connect : %d ", tlsDataParams->ssl.state);
    mbedtls_ssl_set_bio(&(tlsDataParams->ssl), &(tlsDataParams->server_fd), mbedtls_net_send, NULL,
                        mbedtls_net_recv_timeout);
    ESP_LOGD(TAG, "ok");

    ESP_LOGD(TAG, "SSL state connect : %d ", tlsDataParams->ssl.state);
    ESP_LOGD(TAG, "Performing the SSL/TLS handshake...");
    while((ret = mbedtls_ssl_handshake(&(tlsDataParams->ssl))) != 0) {
        if(ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
            ESP_LOGE(TAG, "failed! mbedtls_ssl_handshake returned -0x%x", -ret);
            if(ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
                ESP_LOGE(TAG, "    Unable to verify the server's certificate. ");
            }
            return SSL_CONNECTION_ERROR;
        }
    }

    ESP_LOGD(TAG, "ok    [ Protocol is %s ]    [ Ciphersuite is %s ]", mbedtls_ssl_get_version(&(tlsDataParams->ssl)),
          mbedtls_ssl_get_ciphersuite(&(tlsDataParams->ssl)));
    if((ret = mbedtls_ssl_get_record_expansion(&(tlsDataParams->ssl))) >= 0) {
        ESP_LOGD(TAG, "    [ Record expansion is %d ]", ret);
    } else {
        ESP_LOGD(TAG, "    [ Record expansion is unknown (compression) ]");
    }

    ESP_LOGD(TAG, "Verifying peer X.509 certificate...");

    if(pNetwork->tlsConnectParams.ServerVerificationFlag == true) {
        if((tlsDataParams->flags = mbedtls_ssl_get_verify_result(&(tlsDataParams->ssl))) != 0) {
            ESP_LOGE(TAG, "failed");
            mbedtls_x509_crt_verify_info(info_buf, sizeof(info_buf), "  ! ", tlsDataParams->flags);
            ESP_LOGE(TAG, "%s", info_buf);
            ret = SSL_CONNECTION_ERROR;
        } else {
            ESP_LOGD(TAG, "ok");
            ret = SUCCESS;
        }
    } else {
        ESP_LOGW(TAG, " Server Verification skipped");
        ret = SUCCESS;
    }

    if(LOG_LOCAL_LEVEL >= ESP_LOG_DEBUG) {
        if (mbedtls_ssl_get_peer_cert(&(tlsDataParams->ssl)) != NULL) {
            ESP_LOGD(TAG, "Peer certificate information:");
            mbedtls_x509_crt_info((char *) info_buf, sizeof(info_buf) - 1, "      ", mbedtls_ssl_get_peer_cert(&(tlsDataParams->ssl)));
            ESP_LOGD(TAG, "%s", info_buf);
        }
    }

    return (IoT_Error_t) ret;
}
Ejemplo n.º 4
0
int conn_link_open(struct conn_link_s *link, int *sock, bool use_ssl,
                   uint32_t recv_timeout_ms, uint32_t send_timeout_ms)
{
  DEBUGASSERT(link->sock < 0);
#ifdef CONFIG_THINGSEE_HTTPS_PROTOCOL
  DEBUGASSERT(link->ssl == NULL);
#ifdef CONFIG_MBEDTLS
  DEBUGASSERT(link->net.fd < 0);
#endif
#endif

  link->send_timeout_ms = send_timeout_ms;
  link->recv_timeout_ms = recv_timeout_ms;

  if (!use_ssl)
    {
      link->sock = *sock;
      *sock = -1;
      return OK;
    }
  else
    {
#ifdef CONFIG_THINGSEE_HTTPS_PROTOCOL
#ifdef CONFIG_MBEDTLS
      int ret;
      struct timeval tv;

      if (!g_https_data.initialized)
        {
          con_dbg_save_pos();

          if (conn_link_mbedtls_initialize() < 0)
            return ERROR;
        }

      mbedtls_ssl_conf_read_timeout(&g_https_data.mbedtls->conf,
                                    link->recv_timeout_ms);

      /* Set up a send timeout */

      tv.tv_sec = link->send_timeout_ms / 1000;
      tv.tv_usec = (link->send_timeout_ms % 1000) * 1000;

      ret = setsockopt(*sock, SOL_SOCKET, SO_SNDTIMEO, &tv,
                       sizeof(struct timeval));
      if (ret < 0)
        {
          con_dbg("Setting SO_SNDTIMEO failed, errno: %d\n", errno);
          /* Return here. Socket is more than likely broken */
          return ERROR;
        }
      else
        {
          http_con_dbg("SO_SNDTIMEO := %d msecs\n", link->send_timeout_ms);
        }

      /* Set up a receive timeout */

      tv.tv_sec = link->recv_timeout_ms / 1000;
      tv.tv_usec = (link->recv_timeout_ms % 1000) * 1000;

      ret = setsockopt(*sock, SOL_SOCKET, SO_RCVTIMEO, &tv,
                       sizeof(struct timeval));
      if (ret < 0)
        {
          con_dbg("Setting SO_RCVTIMEO failed, errno: %d\n", errno);
          /* Return if ERROR occurred */
          return ERROR;
        }
      else
        {
          http_con_dbg("SO_RCVTIMEO := %d msecs\n", link->recv_timeout_ms);
        }

      con_dbg_save_pos();

      link->ssl = malloc(sizeof(*link->ssl));
      if (!link->ssl)
        return -1;

      mbedtls_ssl_init(link->ssl);

      ret = mbedtls_ssl_setup(link->ssl, &g_https_data.mbedtls->conf);
      if (ret != 0)
        {
          con_dbg("mbedtls_ssl_setup error: -0x%x\n", -ret);
          goto err_close_tls;
        }

      link->net.fd = *sock;
      link->sock = link->net.fd;
      *sock = -1;

      ret = mbedtls_ssl_set_session(link->ssl,
                                    &g_https_data.mbedtls->saved_session);
      if (ret != 0)
        {
          con_dbg( "mbedtls_ssl_set_session error: -0x%x\n\n", -ret);
        }

      mbedtls_ssl_set_bio(link->ssl, &link->net, mbedtls_net_send,
                          mbedtls_net_recv, mbedtls_net_recv_timeout);

      ret = mbedtls_ssl_handshake(link->ssl);
      if (ret != 0)
        {
          int lowlevel_err = -(-ret & 0x007F);
          int highlevel_err = -(-ret & 0x7F80);

          con_dbg("mbedtls_ssl_handshake error: -0x%x\n", -ret);

          /* Check out-of-memory cases. If we have run out memory or memory
           * has become too fragmented, device will be stuck in bad state.
           * In this case, it will be better to reset.
           * TODO: Should we add controlled reset? */

          DEBUGASSERT(lowlevel_err != MBEDTLS_ERR_MPI_ALLOC_FAILED);
          DEBUGASSERT(lowlevel_err != MBEDTLS_ERR_ASN1_ALLOC_FAILED);
          DEBUGASSERT(highlevel_err != MBEDTLS_ERR_X509_ALLOC_FAILED);
          DEBUGASSERT(highlevel_err != MBEDTLS_ERR_DHM_ALLOC_FAILED);
          DEBUGASSERT(highlevel_err != MBEDTLS_ERR_PK_ALLOC_FAILED);
          DEBUGASSERT(highlevel_err != MBEDTLS_ERR_ECP_ALLOC_FAILED);
          DEBUGASSERT(highlevel_err != MBEDTLS_ERR_CIPHER_ALLOC_FAILED);
          DEBUGASSERT(highlevel_err != MBEDTLS_ERR_SSL_ALLOC_FAILED);

          goto err_close_tls;
        }

      con_dbg("%c[38;5;%d48;5;%dm"
                   "HTTPS: TLS version is '%s'."
                   "%c[0m\n", 0x1B, 0, 1,
                   mbedtls_ssl_get_version(link->ssl), 0x1B);
      con_dbg("%c[38;5;%d48;5;%dm"
                   "HTTPS: TLS cipher suite is '%s'."
                   "%c[0m\n", 0x1B, 0, 1,
                   mbedtls_ssl_get_ciphersuite(link->ssl), 0x1B);

      ret = mbedtls_ssl_get_session(link->ssl,
                                    &g_https_data.mbedtls->saved_session);
      if (ret != 0)
        {
          con_dbg( "mbedtls_ssl_get_session error: -0x%x\n\n", -ret);
        }

      return OK;

err_close_tls:
      con_dbg_save_pos();
      mbedtls_ssl_free(link->ssl);
      free(link->ssl);
      link->ssl = NULL;
      return ERROR;

#endif
#endif
      return ERROR;
    }
}
int iot_tls_connect(Network *pNetwork, TLSConnectParams params) {
	const char *pers = "aws_iot_tls_wrapper";
	unsigned char buf[MBEDTLS_SSL_MAX_CONTENT_LEN + 1];

	DEBUG("  . Loading the CA root certificate ...");
	ret = mbedtls_x509_crt_parse_file(&cacert, params.pRootCALocation);
	if (ret < 0) {
		ERROR(" failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n", -ret);
		return ret;
	} DEBUG(" ok (%d skipped)\n", ret);

	DEBUG("  . Loading the client cert. and key...");
	ret = mbedtls_x509_crt_parse_file(&clicert, params.pDeviceCertLocation);
	if (ret != 0) {
		ERROR(" failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n", -ret);
		return ret;
	}

	ret = mbedtls_pk_parse_keyfile(&pkey, params.pDevicePrivateKeyLocation, "");
	if (ret != 0) {
		ERROR(" failed\n  !  mbedtls_pk_parse_key returned -0x%x\n\n", -ret);
		return ret;
	} DEBUG(" ok\n");
	char portBuffer[6];
	sprintf(portBuffer, "%d", params.DestinationPort); DEBUG("  . Connecting to %s/%s...", params.pDestinationURL, portBuffer);
	if ((ret = mbedtls_net_connect(&server_fd, params.pDestinationURL, portBuffer, MBEDTLS_NET_PROTO_TCP)) != 0) {
		ERROR(" failed\n  ! mbedtls_net_connect returned -0x%x\n\n", -ret);
		return ret;
	}

	ret = mbedtls_net_set_block(&server_fd);
	if (ret != 0) {
		ERROR(" failed\n  ! net_set_(non)block() returned -0x%x\n\n", -ret);
		return ret;
	} DEBUG(" ok\n");

	DEBUG("  . Setting up the SSL/TLS structure...");
	if ((ret = mbedtls_ssl_config_defaults(&conf, MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM,
			MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_config_defaults returned -0x%x\n\n", -ret);
		return ret;
	}

	mbedtls_ssl_conf_verify(&conf, myCertVerify, NULL);
	if (params.ServerVerificationFlag == true) {
		mbedtls_ssl_conf_authmode(&conf, MBEDTLS_SSL_VERIFY_REQUIRED);
	} else {
		mbedtls_ssl_conf_authmode(&conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
	}
	mbedtls_ssl_conf_rng(&conf, mbedtls_ctr_drbg_random, &ctr_drbg);

	mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
	if ((ret = mbedtls_ssl_conf_own_cert(&conf, &clicert, &pkey)) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret);
		return ret;
	}

	mbedtls_ssl_conf_read_timeout(&conf, params.timeout_ms);

	if ((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_setup returned -0x%x\n\n", -ret);
		return ret;
	}
	if ((ret = mbedtls_ssl_set_hostname(&ssl, params.pDestinationURL)) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n", ret);
		return ret;
	}
	mbedtls_ssl_set_bio(&ssl, &server_fd, mbedtls_net_send, NULL, mbedtls_net_recv_timeout);
	DEBUG(" ok\n");

	DEBUG("  . Performing the SSL/TLS handshake...");
	while ((ret = mbedtls_ssl_handshake(&ssl)) != 0) {
		if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
			ERROR(" failed\n  ! mbedtls_ssl_handshake returned -0x%x\n", -ret);
			if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
				ERROR("    Unable to verify the server's certificate. "
						"Either it is invalid,\n"
						"    or you didn't set ca_file or ca_path "
						"to an appropriate value.\n"
						"    Alternatively, you may want to use "
						"auth_mode=optional for testing purposes.\n");
			}
			return ret;
		}
	}

	DEBUG(" ok\n    [ Protocol is %s ]\n    [ Ciphersuite is %s ]\n", mbedtls_ssl_get_version(&ssl), mbedtls_ssl_get_ciphersuite(&ssl));
	if ((ret = mbedtls_ssl_get_record_expansion(&ssl)) >= 0) {
		DEBUG("    [ Record expansion is %d ]\n", ret);
	} else {
		DEBUG("    [ Record expansion is unknown (compression) ]\n");
	}

	DEBUG("  . Verifying peer X.509 certificate...");

	if (params.ServerVerificationFlag == true) {
		if ((flags = mbedtls_ssl_get_verify_result(&ssl)) != 0) {
			char vrfy_buf[512];
			ERROR(" failed\n");
			mbedtls_x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), "  ! ", flags);
			ERROR("%s\n", vrfy_buf);
		} else {
			DEBUG(" ok\n");
			ret = NONE_ERROR;
		}
	} else {
		DEBUG(" Server Verification skipped\n");
		ret = NONE_ERROR;
	}

	if (mbedtls_ssl_get_peer_cert(&ssl) != NULL) {
		DEBUG("  . Peer certificate information    ...\n");
		mbedtls_x509_crt_info((char *) buf, sizeof(buf) - 1, "      ", mbedtls_ssl_get_peer_cert(&ssl));
		DEBUG("%s\n", buf);
	}

	mbedtls_ssl_conf_read_timeout(&conf, 10);

	return ret;
}
IoT_Error_t iot_tls_connect(Network *pNetwork, TLSConnectParams *params) {
	if(NULL == pNetwork) {
		return NULL_VALUE_ERROR;
	}

	if(NULL != params) {
		_iot_tls_set_connect_params(pNetwork, params->pRootCALocation, params->pDeviceCertLocation,
									params->pDevicePrivateKeyLocation, params->pDestinationURL,
									params->DestinationPort, params->timeout_ms, params->ServerVerificationFlag);
	}

	int ret = 0;
	const char *pers = "aws_iot_tls_wrapper";
#ifdef IOT_DEBUG
	unsigned char buf[MBEDTLS_SSL_MAX_CONTENT_LEN + 1];
#endif
	TLSDataParams *tlsDataParams = &(pNetwork->tlsDataParams);

	mbedtls_net_init(&(tlsDataParams->server_fd));
	mbedtls_ssl_init(&(tlsDataParams->ssl));
	mbedtls_ssl_config_init(&(tlsDataParams->conf));
	mbedtls_ctr_drbg_init(&(tlsDataParams->ctr_drbg));
	mbedtls_x509_crt_init(&(tlsDataParams->cacert));
	mbedtls_x509_crt_init(&(tlsDataParams->clicert));
	mbedtls_pk_init(&(tlsDataParams->pkey));

	DEBUG("\n  . Seeding the random number generator...");
	mbedtls_entropy_init(&(tlsDataParams->entropy));
	if ((ret = mbedtls_ctr_drbg_seed(&(tlsDataParams->ctr_drbg), mbedtls_entropy_func, &(tlsDataParams->entropy),
										(const unsigned char *) pers, strlen(pers))) != 0) {
		ERROR(" failed\n  ! mbedtls_ctr_drbg_seed returned -0x%x\n", -ret);
		return NETWORK_MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED;
	}

	DEBUG("  . Loading the CA root certificate ...");
	ret = mbedtls_x509_crt_parse_file(&(tlsDataParams->cacert), pNetwork->tlsConnectParams.pRootCALocation);
	if (ret < 0) {
		ERROR(" failed\n  !  mbedtls_x509_crt_parse returned -0x%x while parsing root cert\n\n", -ret);
		return NETWORK_X509_ROOT_CRT_PARSE_ERROR;
	} DEBUG(" ok (%d skipped)\n", ret);

	DEBUG("  . Loading the client cert. and key...");
	ret = mbedtls_x509_crt_parse_file(&(tlsDataParams->clicert), pNetwork->tlsConnectParams.pDeviceCertLocation);
	if (ret != 0) {
		ERROR(" failed\n  !  mbedtls_x509_crt_parse returned -0x%x while parsing device cert\n\n", -ret);
		return NETWORK_X509_DEVICE_CRT_PARSE_ERROR;
	}

	ret = mbedtls_pk_parse_keyfile(&(tlsDataParams->pkey), pNetwork->tlsConnectParams.pDevicePrivateKeyLocation, "");
	if (ret != 0) {
		ERROR(" failed\n  !  mbedtls_pk_parse_key returned -0x%x while parsing private key\n\n", -ret);
		DEBUG(" path : %s ", pNetwork->tlsConnectParams.pDevicePrivateKeyLocation);
		return NETWORK_PK_PRIVATE_KEY_PARSE_ERROR;
	} DEBUG(" ok\n");
	char portBuffer[6];
	snprintf(portBuffer, 6, "%d", pNetwork->tlsConnectParams.DestinationPort);
	DEBUG("  . Connecting to %s/%s...", pNetwork->tlsConnectParams.pDestinationURL, portBuffer);
	if ((ret = mbedtls_net_connect(&(tlsDataParams->server_fd), pNetwork->tlsConnectParams.pDestinationURL,
								   portBuffer, MBEDTLS_NET_PROTO_TCP)) != 0) {
		ERROR(" failed\n  ! mbedtls_net_connect returned -0x%x\n\n", -ret);
		switch(ret) {
			case MBEDTLS_ERR_NET_SOCKET_FAILED:
				return NETWORK_ERR_NET_SOCKET_FAILED;
			case MBEDTLS_ERR_NET_UNKNOWN_HOST:
				return NETWORK_ERR_NET_UNKNOWN_HOST;
			case MBEDTLS_ERR_NET_CONNECT_FAILED:
			default:
				return NETWORK_ERR_NET_CONNECT_FAILED;
		};
	}

	ret = mbedtls_net_set_block(&(tlsDataParams->server_fd));
	if (ret != 0) {
		ERROR(" failed\n  ! net_set_(non)block() returned -0x%x\n\n", -ret);
		return SSL_CONNECTION_ERROR;
	} DEBUG(" ok\n");

	DEBUG("  . Setting up the SSL/TLS structure...");
	if ((ret = mbedtls_ssl_config_defaults(&(tlsDataParams->conf), MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM,
			MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_config_defaults returned -0x%x\n\n", -ret);
		return SSL_CONNECTION_ERROR;
	}

	mbedtls_ssl_conf_verify(&(tlsDataParams->conf), _iot_tls_verify_cert, NULL);
	if (pNetwork->tlsConnectParams.ServerVerificationFlag == true) {
		mbedtls_ssl_conf_authmode(&(tlsDataParams->conf), MBEDTLS_SSL_VERIFY_REQUIRED);
	} else {
		mbedtls_ssl_conf_authmode(&(tlsDataParams->conf), MBEDTLS_SSL_VERIFY_OPTIONAL);
	}
	mbedtls_ssl_conf_rng(&(tlsDataParams->conf), mbedtls_ctr_drbg_random, &(tlsDataParams->ctr_drbg));

	mbedtls_ssl_conf_ca_chain(&(tlsDataParams->conf), &(tlsDataParams->cacert), NULL);
	if ((ret = mbedtls_ssl_conf_own_cert(&(tlsDataParams->conf), &(tlsDataParams->clicert), &(tlsDataParams->pkey))) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret);
		return SSL_CONNECTION_ERROR;
	}

	mbedtls_ssl_conf_read_timeout(&(tlsDataParams->conf), pNetwork->tlsConnectParams.timeout_ms);

	if ((ret = mbedtls_ssl_setup(&(tlsDataParams->ssl), &(tlsDataParams->conf))) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_setup returned -0x%x\n\n", -ret);
		return SSL_CONNECTION_ERROR;
	}
	if ((ret = mbedtls_ssl_set_hostname(&(tlsDataParams->ssl), pNetwork->tlsConnectParams.pDestinationURL)) != 0) {
		ERROR(" failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n", ret);
		return SSL_CONNECTION_ERROR;
	}
	DEBUG("\n\nSSL state connect : %d ", tlsDataParams->ssl.state);
	mbedtls_ssl_set_bio(&(tlsDataParams->ssl), &(tlsDataParams->server_fd), mbedtls_net_send, NULL, mbedtls_net_recv_timeout);
	DEBUG(" ok\n");

	DEBUG("\n\nSSL state connect : %d ", tlsDataParams->ssl.state);
	DEBUG("  . Performing the SSL/TLS handshake...");
	while ((ret = mbedtls_ssl_handshake(&(tlsDataParams->ssl))) != 0) {
		if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
			ERROR(" failed\n  ! mbedtls_ssl_handshake returned -0x%x\n", -ret);
			if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
				ERROR("    Unable to verify the server's certificate. "
						"Either it is invalid,\n"
						"    or you didn't set ca_file or ca_path "
						"to an appropriate value.\n"
						"    Alternatively, you may want to use "
						"auth_mode=optional for testing purposes.\n");
			}
			return SSL_CONNECTION_ERROR;
		}
	}

	DEBUG(" ok\n    [ Protocol is %s ]\n    [ Ciphersuite is %s ]\n", mbedtls_ssl_get_version(&(tlsDataParams->ssl)), mbedtls_ssl_get_ciphersuite(&(tlsDataParams->ssl)));
	if ((ret = mbedtls_ssl_get_record_expansion(&(tlsDataParams->ssl))) >= 0) {
		DEBUG("    [ Record expansion is %d ]\n", ret);
	} else {
		DEBUG("    [ Record expansion is unknown (compression) ]\n");
	}

	DEBUG("  . Verifying peer X.509 certificate...");

	if(pNetwork->tlsConnectParams.ServerVerificationFlag == true) {
		if((tlsDataParams->flags = mbedtls_ssl_get_verify_result(&(tlsDataParams->ssl))) != 0) {
			char vrfy_buf[512];
			ERROR(" failed\n");
			mbedtls_x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), "  ! ", tlsDataParams->flags);
			ERROR("%s\n", vrfy_buf);
			ret = SSL_CONNECTION_ERROR;
		} else {
			DEBUG(" ok\n");
			ret = SUCCESS;
		}
	} else {
		DEBUG(" Server Verification skipped\n");
		ret = SUCCESS;
	}

#ifdef IOT_DEBUG
	if (mbedtls_ssl_get_peer_cert(&(tlsDataParams->ssl)) != NULL) {
		DEBUG("  . Peer certificate information    ...\n");
		mbedtls_x509_crt_info((char *) buf, sizeof(buf) - 1, "      ", mbedtls_ssl_get_peer_cert(&(tlsDataParams->ssl)));
		DEBUG("%s\n", buf);
	}
#endif

	mbedtls_ssl_conf_read_timeout(&(tlsDataParams->conf), IOT_SSL_READ_TIMEOUT);

	return ret;
}