/* http_get_mbedtls - HTTPS version of the http_get example, using mbed TLS.
*
* Retrieves a JSON response from the howsmyssl.com API via HTTPS over TLS v1.2.
*
* Validates the server's certificate using the root CA loaded (in PEM format) in cert.c.
*
* Adapted from the ssl_client1 example in mbedtls.
*
* Original Copyright (C) 2006-2015, ARM Limited, All Rights Reserved, Apache 2.0 License.
* Additions Copyright (C) 2015 Angus Gratton, Apache 2.0 License.
*/
#include "espressif/esp_common.h"
#include "esp/uart.h"
#include <string.h>
#include "FreeRTOS.h"
#include "task.h"
#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include "lwip/netdb.h"
#include "lwip/dns.h"
#include "lwip/api.h"
#include "ssid_config.h"
/* mbedtls/config.h MUST appear before all other mbedtls headers, or
you'll get the default config.
(Although mostly that isn't a big problem, you just might get
errors at link time if functions don't exist.) */
#include "mbedtls/config.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"
#define WEB_SERVER "www.howsmyssl.com"
#define WEB_PORT "443"
#define WEB_URL "https://www.howsmyssl.com/a/check"
#define GET_REQUEST "GET "WEB_URL" HTTP/1.1\nHost: "WEB_SERVER"\n\n"
/* Root cert for howsmyssl.com, stored in cert.c */
extern const char *server_root_cert;
/* MBEDTLS_DEBUG_C disabled by default to save substantial bloating of
* firmware, define it in
* examples/http_get_mbedtls/include/mbedtls/config.h if you'd like
* debugging output.
*/
#ifdef MBEDTLS_DEBUG_C
/* Increase this value to see more TLS debug details,
0 prints nothing, 1 will print any errors, 4 will print _everything_
*/
#define DEBUG_LEVEL 4
static void my_debug(void *ctx, int level,
const char *file, int line,
const char *str)
{
((void) level);
/* 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, so the firmware is bloated out
by a few kb. But there's not a lot we can do about it...
*/
char *file_sep = rindex(file, '/');
if(file_sep)
file = file_sep+1;
printf("%s:%04d: %s", file, line, str);
}
#endif
void http_get_task(void *pvParameters)
{
int successes = 0, failures = 0, ret;
printf("HTTP get task starting...\n");
uint32_t flags;
unsigned char buf[1024];
const char *pers = "ssl_client1";
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;
/*
* 0. Initialize the RNG and the session data
*/
mbedtls_ssl_init(&ssl);
mbedtls_x509_crt_init(&cacert);
mbedtls_ctr_drbg_init(&ctr_drbg);
printf("\n . 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,
(const unsigned char *) pers,
strlen(pers))) != 0)
{
printf(" failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret);
abort();
}
printf(" ok\n");
/*
* 0. Initialize certificates
*/
printf(" . Loading the CA root certificate ...");
ret = mbedtls_x509_crt_parse(&cacert, (uint8_t*)server_root_cert, strlen(server_root_cert)+1);
if(ret < 0)
{
printf(" failed\n ! mbedtls_x509_crt_parse returned -0x%x\n\n", -ret);
abort();
}
printf(" ok (%d skipped)\n", ret);
/* Hostname set here should match CN in server certificate */
if((ret = mbedtls_ssl_set_hostname(&ssl, WEB_SERVER)) != 0)
{
printf(" failed\n ! mbedtls_ssl_set_hostname returned %d\n\n", ret);
abort();
}
/*
* 2. Setup stuff
*/
printf(" . 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)
{
printf(" failed\n ! mbedtls_ssl_config_defaults returned %d\n\n", ret);
goto exit;
}
printf(" ok\n");
/* OPTIONAL is not optimal for security, in this example it will print
a warning if CA verification fails but it will continue to connect.
*/
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(DEBUG_LEVEL);
mbedtls_ssl_conf_dbg(&conf, my_debug, stdout);
#endif
if((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0)
{
printf(" failed\n ! mbedtls_ssl_setup returned %d\n\n", ret);
goto exit;
}
/* Wait until we can resolve the DNS for the server, as an indication
our network is probably working...
*/
printf("Waiting for server DNS to resolve... ");
err_t dns_err;
ip_addr_t host_ip;
do {
vTaskDelay(500 / portTICK_PERIOD_MS);
dns_err = netconn_gethostbyname(WEB_SERVER, &host_ip);
} while(dns_err != ERR_OK);
printf("done.\n");
while(1) {
mbedtls_net_init(&server_fd);
printf("top of loop, free heap = %u\n", xPortGetFreeHeapSize());
/*
* 1. Start the connection
*/
printf(" . Connecting to %s:%s...", WEB_SERVER, WEB_PORT);
if((ret = mbedtls_net_connect(&server_fd, WEB_SERVER,
WEB_PORT, MBEDTLS_NET_PROTO_TCP)) != 0)
{
printf(" failed\n ! mbedtls_net_connect returned %d\n\n", ret);
goto exit;
}
printf(" ok\n");
mbedtls_ssl_set_bio(&ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv, NULL);
/*
* 4. Handshake
*/
printf(" . 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)
{
printf(" failed\n ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret);
goto exit;
}
}
printf(" ok\n");
/*
* 5. Verify the server certificate
*/
printf(" . Verifying peer X.509 certificate...");
/* In real life, we probably want to bail out when ret != 0 */
if((flags = mbedtls_ssl_get_verify_result(&ssl)) != 0)
{
char vrfy_buf[512];
printf(" failed\n");
mbedtls_x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), " ! ", flags);
printf("%s\n", vrfy_buf);
}
else
printf(" ok\n");
/*
* 3. Write the GET request
*/
printf(" > Write to server:");
int len = sprintf((char *) buf, GET_REQUEST);
while((ret = mbedtls_ssl_write(&ssl, buf, len)) <= 0)
{
if(ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
{
printf(" failed\n ! mbedtls_ssl_write returned %d\n\n", ret);
goto exit;
}
}
len = ret;
printf(" %d bytes written\n\n%s", len, (char *) buf);
/*
* 7. Read the HTTP response
*/
printf(" < Read from server:");
do
{
len = sizeof(buf) - 1;
memset(buf, 0, sizeof(buf));
ret = mbedtls_ssl_read(&ssl, 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)
{
printf("failed\n ! mbedtls_ssl_read returned %d\n\n", ret);
break;
}
if(ret == 0)
{
printf("\n\nEOF\n\n");
break;
}
len = ret;
printf(" %d bytes read\n\n%s", len, (char *) buf);
} while(1);
mbedtls_ssl_close_notify(&ssl);
exit:
mbedtls_ssl_session_reset(&ssl);
mbedtls_net_free(&server_fd);
if(ret != 0)
{
char error_buf[100];
mbedtls_strerror(ret, error_buf, 100);
printf("\n\nLast error was: %d - %s\n\n", ret, error_buf);
failures++;
} else {
successes++;
}
printf("\n\nsuccesses = %d failures = %d\n", successes, failures);
for(int countdown = successes ? 10 : 5; countdown >= 0; countdown--) {
printf("%d... ", countdown);
vTaskDelay(1000 / portTICK_PERIOD_MS);
}
printf("\nStarting again!\n");
}
}
void user_init(void)
{
uart_set_baud(0, 115200);
printf("SDK version:%s\n", sdk_system_get_sdk_version());
struct sdk_station_config config = {
.ssid = WIFI_SSID,
.password = WIFI_PASS,
};
/* required to call wifi_set_opmode before station_set_config */
sdk_wifi_set_opmode(STATION_MODE);
sdk_wifi_station_set_config(&config);
xTaskCreate(&http_get_task, "get_task", 2048, NULL, 2, NULL);
}