esp-idf/examples/03_https_request/main/https_request_main.c

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2016-09-21 02:44:27 -04:00
/* HTTPS GET Example using plain mbedTLS sockets
*
* Contacts the howsmyssl.com API via TLS v1.2 and reads a JSON
* response.
*
* Adapted from the ssl_client1 example in mbedtls.
*
* Original Copyright (C) 2006-2016, ARM Limited, All Rights Reserved, Apache 2.0 License.
* Additions Copyright (C) Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD, Apache 2.0 License.
*
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_system.h"
#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include "lwip/netdb.h"
#include "lwip/dns.h"
#include "mbedtls/net.h"
#include "mbedtls/debug.h"
#include "mbedtls/ssl.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/error.h"
#include "mbedtls/certs.h"
/* The examples use simple WiFi configuration that you can set via
'make menuconfig'.
If you'd rather not, just change the below entries to strings with
the config you want - ie #define EXAMPLE_WIFI_SSID "mywifissid"
*/
#define EXAMPLE_WIFI_SSID CONFIG_WIFI_SSID
#define EXAMPLE_WIFI_PASS CONFIG_WIFI_PASSWORD
/* Flag for when we are connected & ready to make a request */
static volatile bool ready;
/* Constants that aren't configurable in menuconfig */
#define WEB_SERVER "www.howsmyssl.com"
#define WEB_PORT "443"
#define WEB_URL "https://www.howsmyssl.com/a/check"
static const char *TAG = "example";
static const char *REQUEST = "GET " WEB_URL " HTTP/1.1\n"
"Host: "WEB_SERVER"\n"
"User-Agent: esp-idf/1.0 esp32\n"
"\n";
/* Root cert for howsmyssl.com, found in cert.c */
extern const char *server_root_cert;
#ifdef MBEDTLS_DEBUG_C
#define MBEDTLS_DEBUG_LEVEL 4
/* mbedtls debug function that translates mbedTLS debug output
to ESP_LOGx debug output.
MBEDTLS_DEBUG_LEVEL 4 means all mbedTLS debug output gets sent here,
and then filtered to the
*/
static void mbedtls_debug(void *ctx, int level,
const char *file, int line,
const char *str)
{
const char *MBTAG = "mbedtls";
char *file_sep;
/* Shorten 'file' from the whole file path to just the filename
This is a bit wasteful because the macros are compiled in with
the full _FILE_ path in each case.
*/
file_sep = rindex(file, '/');
if(file_sep)
file = file_sep+1;
switch(level) {
case 1:
ESP_LOGI(MBTAG, "%s:%d %s", file, line, str);
break;
case 2:
case 3:
ESP_LOGD(MBTAG, "%s:%d %s", file, line, str);
case 4:
ESP_LOGV(MBTAG, "%s:%d %s", file, line, str);
break;
default:
ESP_LOGE(MBTAG, "Unexpected log level %d: %s", level, str);
break;
}
}
#endif
static esp_err_t wifi_event_cb(void *ctx, system_event_t *event)
{
switch(event->event_id) {
case SYSTEM_EVENT_STA_GOT_IP:
ready = true;
break;
case SYSTEM_EVENT_STA_DISCONNECTED:
ready = false;
break;
default:
break;
}
return ESP_OK;
}
static void set_wifi_configuration(void)
{
wifi_config_t wifi_config = {
.sta = {
.ssid = EXAMPLE_WIFI_SSID,
.password = EXAMPLE_WIFI_PASS,
},
};
ESP_LOGI(TAG, "Setting WiFi configuration SSID %s...", wifi_config.sta.ssid);
esp_wifi_set_mode(WIFI_MODE_STA);
esp_wifi_set_config(WIFI_IF_STA, &wifi_config);
}
static void https_get_task(void *pvParameters)
{
char buf[512];
int ret, flags, len;
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_ssl_context ssl;
mbedtls_x509_crt cacert;
mbedtls_ssl_config conf;
mbedtls_net_context server_fd;
esp_wifi_connect();
mbedtls_ssl_init(&ssl);
mbedtls_x509_crt_init(&cacert);
mbedtls_ctr_drbg_init(&ctr_drbg);
ESP_LOGI(TAG, "Seeding the random number generator");
mbedtls_ssl_config_init(&conf);
mbedtls_entropy_init(&entropy);
if((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
NULL, 0)) != 0)
{
ESP_LOGE(TAG, "mbedtls_ctr_drbg_seed returned %d", ret);
abort();
}
ESP_LOGI(TAG, "Loading the CA root certificate...");
ret = mbedtls_x509_crt_parse(&cacert, (uint8_t*)server_root_cert, strlen(server_root_cert)+1);
if(ret < 0)
{
ESP_LOGE(TAG, "mbedtls_x509_crt_parse returned -0x%x\n\n", -ret);
abort();
}
ESP_LOGI(TAG, "Setting hostname for TLS session...");
/* Hostname set here should match CN in server certificate */
if((ret = mbedtls_ssl_set_hostname(&ssl, WEB_SERVER)) != 0)
{
ESP_LOGE(TAG, "mbedtls_ssl_set_hostname returned -0x%x", -ret);
abort();
}
ESP_LOGI(TAG, "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)
{
ESP_LOGE(TAG, "mbedtls_ssl_config_defaults returned %d", ret);
goto exit;
}
/* MBEDTLS_SSL_VERIFY_OPTIONAL is bad for security, in this example it will print
a warning if CA verification fails but it will continue to connect.
You should consider using MBEDTLS_SSL_VERIFY_REQUIRED in your own code.
*/
mbedtls_ssl_conf_authmode(&conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
mbedtls_ssl_conf_rng(&conf, mbedtls_ctr_drbg_random, &ctr_drbg);
#ifdef MBEDTLS_DEBUG_C
mbedtls_debug_set_threshold(MBEDTLS_DEBUG_LEVEL);
mbedtls_ssl_conf_dbg(&conf, mbedtls_debug, NULL);
#endif
ESP_LOGI(TAG, "%d free...", system_get_free_heap_size());
char *x = malloc(8192);
memset(x, 'a', 8192);
ESP_LOGI(TAG, "%d free now...", system_get_free_heap_size());
if ((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0)
{
ESP_LOGE(TAG, "mbedtls_ssl_setup returned -0x%x\n\n", -ret);
goto exit;
}
ESP_LOGI(TAG, "Waiting for WiFi online...");
while (!ready) {
vTaskDelay(1);
}
ESP_LOGI(TAG, "WiFi is online");
while(1) {
ESP_LOGI(TAG, "Connecting to %s:%s...", WEB_SERVER, WEB_PORT);
mbedtls_net_init(&server_fd);
if ((ret = mbedtls_net_connect(&server_fd, WEB_SERVER,
WEB_PORT, MBEDTLS_NET_PROTO_TCP)) != 0)
{
ESP_LOGE(TAG, "mbedtls_net_connect returned -%x", -ret);
goto exit;
}
ESP_LOGI(TAG, "Connected.");
mbedtls_ssl_set_bio(&ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv, NULL);
ESP_LOGI(TAG, "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)
{
ESP_LOGE(TAG, "mbedtls_ssl_handshake returned -0x%x", -ret);
goto exit;
}
}
ESP_LOGI(TAG, "Verifying peer X.509 certificate...");
if ((flags = mbedtls_ssl_get_verify_result(&ssl)) != 0)
{
/* In real life, we probably want to close connection if ret != 0 */
ESP_LOGW(TAG, "Failed to verify peer certificate!");
bzero(buf, sizeof(buf));
mbedtls_x509_crt_verify_info(buf, sizeof(buf), " ! ", flags);
ESP_LOGW(TAG, "verification info: %s", buf);
}
else {
ESP_LOGI(TAG, "Certificate verified.");
}
ESP_LOGI(TAG, "Writing HTTP request...");
while((ret = mbedtls_ssl_write(&ssl, (const unsigned char *)REQUEST, strlen(REQUEST))) <= 0)
{
if(ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
{
ESP_LOGE(TAG, "mbedtls_ssl_write returned -0x%x", -ret);
goto exit;
}
}
len = ret;
ESP_LOGI(TAG, "%d bytes written", len);
ESP_LOGI(TAG, "Reading HTTP response...");
do
{
len = sizeof(buf) - 1;
bzero(buf, sizeof(buf));
ret = mbedtls_ssl_read(&ssl, (unsigned char *)buf, len);
if(ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE)
continue;
if(ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY) {
ret = 0;
break;
}
if(ret < 0)
{
ESP_LOGE(TAG, "mbedtls_ssl_read returned -0x%x", -ret);
break;
}
if(ret == 0)
{
ESP_LOGI(TAG, "connection closed");
break;
}
len = ret;
ESP_LOGI(TAG, "%d bytes read", len);
/* Print response directly to stdout as it is read */
for(int i = 0; i < len; i++) {
putchar(buf[i]);
}
} while(1);
mbedtls_ssl_close_notify(&ssl);
exit:
mbedtls_ssl_session_reset(&ssl);
mbedtls_net_free(&server_fd);
if(ret != 0)
{
mbedtls_strerror(ret, buf, 100);
ESP_LOGE(TAG, "Last error was: -0x%x - %s", -ret, buf);
}
for(int countdown = 10; countdown >= 0; countdown--) {
ESP_LOGI(TAG, "%d...", countdown);
vTaskDelay(1000 / portTICK_RATE_MS);
}
ESP_LOGI(TAG, "Starting again!");
}
}
void app_main()
{
esp_event_set_cb(wifi_event_cb, NULL);
set_wifi_configuration();
xTaskCreate(&https_get_task, "https_get_task", 8192, NULL, 5, NULL);
}