ESP8266 as TCP SSL client

ESP_Faye
Posts: 1627
Joined: Mon Oct 27, 2014 11:08 am

ESP8266 as TCP SSL client

Postby ESP_Faye » Wed Apr 22, 2015 11:46 am

Here is a demo code of ESP8266 as TCP SSL client. It is based on ESP8266 SDK without OS.

It just like ESP8266 to be normal TCP client except change espconn_xxx to be espconn_secure_xxx

If your SSL packet is larger than 2048 bytes, please try to call espconn_secure_set_size to enlarge SSL buffer size (max: 8192)

Code: Select all


#include "espconn.h"
#include "mem.h"

#define DNS_ENABLE

unsigned char *default_certificate;
unsigned int default_certificate_len = 0;
unsigned char *default_private_key;
unsigned int default_private_key_len = 0;

#define NET_DOMAIN "iot.espressif.cn"

const char* TLSHEAD = "GET / HTTP/1.1\r\nHost: %d.%d.%d.%d\r\nConnection: keep-alive\r\n\r\n";

#define packet_size   (2 * 1024)

LOCAL os_timer_t test_timer;
LOCAL struct espconn user_tcp_conn;
LOCAL struct _esp_tcp user_tcp;
ip_addr_t tcp_server_ip;

/******************************************************************************
 * FunctionName : user_tcp_recv_cb
 * Description  : receive callback.
 * Parameters   : arg -- Additional argument to pass to the callback function
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_tcp_recv_cb(void *arg, char *pusrdata, unsigned short length)
{
   //received some data from tcp connection
   
    os_printf("tcp recv !!! %s \r\n", pusrdata);
   
}
/******************************************************************************
 * FunctionName : user_tcp_sent_cb
 * Description  : data sent callback.
 * Parameters   : arg -- Additional argument to pass to the callback function
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_tcp_sent_cb(void *arg)
{
   //data sent successfully

    os_printf("tcp sent succeed !!! \r\n");
}
/******************************************************************************
 * FunctionName : user_tcp_discon_cb
 * Description  : disconnect callback.
 * Parameters   : arg -- Additional argument to pass to the callback function
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_tcp_discon_cb(void *arg)
{
   //tcp disconnect successfully
   
    os_printf("tcp disconnect succeed !!! \r\n");
}
/******************************************************************************
 * FunctionName : user_esp_platform_sent
 * Description  : Processing the application data and sending it to the host
 * Parameters   : pespconn -- the espconn used to connetion with the host
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_sent_data(struct espconn *pespconn)
{
   char *pbuf = (char *)os_zalloc(packet_size);

   os_sprintf(pbuf, TLSHEAD,
    pespconn->proto.tcp->remote_ip[0], pespconn->proto.tcp->remote_ip[1],
    pespconn->proto.tcp->remote_ip[2], pespconn->proto.tcp->remote_ip[3]);

   espconn_secure_sent(pespconn, pbuf, os_strlen(pbuf));
   
   os_free(pbuf);

}

/******************************************************************************
 * FunctionName : user_tcp_connect_cb
 * Description  : A new incoming tcp connection has been connected.
 * Parameters   : arg -- Additional argument to pass to the callback function
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_tcp_connect_cb(void *arg)
{
    struct espconn *pespconn = arg;

    os_printf("connect succeed !!! \r\n");

    espconn_regist_recvcb(pespconn, user_tcp_recv_cb);
    espconn_regist_sentcb(pespconn, user_tcp_sent_cb);
   
    user_sent_data(pespconn);
}

/******************************************************************************
 * FunctionName : user_tcp_recon_cb
 * Description  : reconnect callback, error occured in TCP connection.
 * Parameters   : arg -- Additional argument to pass to the callback function
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_tcp_recon_cb(void *arg, sint8 err)
{
   //error occured , tcp connection broke. user can try to reconnect here.
   
    os_printf("reconnect callback, error code %d !!! \r\n",err);
}

#ifdef DNS_ENABLE
/******************************************************************************
 * FunctionName : user_dns_found
 * Description  : dns found callback
 * Parameters   : name -- pointer to the name that was looked up.
 *                ipaddr -- pointer to an ip_addr_t containing the IP address of
 *                the hostname, or NULL if the name could not be found (or on any
 *                other error).
 *                callback_arg -- a user-specified callback argument passed to
 *                dns_gethostbyname
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
{
    struct espconn *pespconn = (struct espconn *)arg;

    if (ipaddr == NULL)
   {
        os_printf("user_dns_found NULL \r\n");
        return;
    }

   //dns got ip
    os_printf("user_dns_found %d.%d.%d.%d \r\n",
            *((uint8 *)&ipaddr->addr), *((uint8 *)&ipaddr->addr + 1),
            *((uint8 *)&ipaddr->addr + 2), *((uint8 *)&ipaddr->addr + 3));

    if (tcp_server_ip.addr == 0 && ipaddr->addr != 0)
   {
      // dns succeed, create tcp connection
        os_timer_disarm(&test_timer);
        tcp_server_ip.addr = ipaddr->addr;
        os_memcpy(pespconn->proto.tcp->remote_ip, &ipaddr->addr, 4); // remote ip of tcp server which get by dns

        pespconn->proto.tcp->remote_port = 8443; // remote SSL port of tcp server
     
        pespconn->proto.tcp->local_port = espconn_port(); //local port of ESP8266

        espconn_regist_connectcb(pespconn, user_tcp_connect_cb); // register connect callback
        espconn_regist_reconcb(pespconn, user_tcp_recon_cb); // register reconnect callback as error handler
        espconn_regist_disconcb(pespconn, user_tcp_discon_cb);  // register disconnect callback here, because that SSL handshake may fail.
       
       espconn_secure_set_size(ESPCONN_CLIENT,5120); // set SSL buffer size, if your SSL packet larger than 2048 bytes
        espconn_secure_connect(pespconn); // tcp SSL connect
    }
}

/******************************************************************************
 * FunctionName : user_esp_platform_dns_check_cb
 * Description  : 1s time callback to check dns found
 * Parameters   : arg -- Additional argument to pass to the callback function
 * Returns      : none
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
user_dns_check_cb(void *arg)
{
    struct espconn *pespconn = arg;

    espconn_gethostbyname(pespconn, NET_DOMAIN, &tcp_server_ip, user_dns_found); // recall DNS function

    os_timer_arm(&test_timer, 1000, 0);
}
#endif

/******************************************************************************
 * FunctionName : user_check_ip
 * Description  : check whether get ip addr or not
 * Parameters   : none
 * Returns      : none
*******************************************************************************/
void ICACHE_FLASH_ATTR
user_check_ip(void)
{
    struct ip_info ipconfig;

   //disarm timer first
    os_timer_disarm(&test_timer);

   //get ip info of ESP8266 station
    wifi_get_ip_info(STATION_IF, &ipconfig);

    if (wifi_station_get_connect_status() == STATION_GOT_IP && ipconfig.ip.addr != 0)
   {
      os_printf("got ip !!! \r\n");

      // Connect to tcp server as NET_DOMAIN
      user_tcp_conn.proto.tcp = &user_tcp;
      user_tcp_conn.type = ESPCONN_TCP;
      user_tcp_conn.state = ESPCONN_NONE;

      #ifdef DNS_ENABLE
      tcp_server_ip.addr = 0;
       espconn_gethostbyname(&user_tcp_conn, NET_DOMAIN, &tcp_server_ip, user_dns_found); // DNS function

       os_timer_setfn(&test_timer, (os_timer_func_t *)user_dns_check_cb, &user_tcp_conn);
       os_timer_arm(&test_timer, 1000, 0);
      #else
       const char esp_server_ip[4] = {192, 185, 229, 242};

       os_memcpy(user_tcp_conn.proto.tcp->remote_ip, esp_server_ip, 4);

       user_tcp_conn.proto.tcp->remote_port = 443; // remote SSL port of tcp server
     
       user_tcp_conn.proto.tcp->local_port = espconn_port(); //local port of ESP8266

       espconn_regist_connectcb(&user_tcp_conn, user_tcp_connect_cb); // register connect callback
       espconn_regist_reconcb(&user_tcp_conn, user_tcp_recon_cb); // register reconnect callback as error handler

       espconn_secure_set_size(ESPCONN_CLIENT,5120); // set SSL buffer size, if your SSL packet larger than 2048 bytes
       espconn_secure_connect(&user_tcp_conn); // tcp SSL connect
      #endif

    }
   else
   {
       
        if ((wifi_station_get_connect_status() == STATION_WRONG_PASSWORD ||
                wifi_station_get_connect_status() == STATION_NO_AP_FOUND ||
                wifi_station_get_connect_status() == STATION_CONNECT_FAIL))
        {
         os_printf("connect fail !!! \r\n");
        }
      else
      {
           //re-arm timer to check ip
            os_timer_setfn(&test_timer, (os_timer_func_t *)user_check_ip, NULL);
            os_timer_arm(&test_timer, 100, 0);
        }
    }
}


/******************************************************************************
 * FunctionName : user_set_station_config
 * Description  : set the router info which ESP8266 station will connect to
 * Parameters   : none
 * Returns      : none
*******************************************************************************/
void ICACHE_FLASH_ATTR
user_set_station_config(void)
{
   // Wifi configuration
   char ssid[32] = SSID;
   char password[64] = PASSWORD;
   struct station_config stationConf;

   //need not mac address
   stationConf.bssid_set = 0;
   
   //Set ap settings
   os_memcpy(&stationConf.ssid, ssid, 32);
   os_memcpy(&stationConf.password, password, 64);
   wifi_station_set_config(&stationConf);

   //set a timer to check whether got ip from router succeed or not.
   os_timer_disarm(&test_timer);
    os_timer_setfn(&test_timer, (os_timer_func_t *)user_check_ip, NULL);
    os_timer_arm(&test_timer, 100, 0);

}


/******************************************************************************
 * FunctionName : user_init
 * Description  : entry of user application, init user function here
 * Parameters   : none
 * Returns      : none
*******************************************************************************/
void user_init(void)
{
    os_printf("SDK version:%s\n", system_get_sdk_version());
   
   //Set station mode
   wifi_set_opmode(STATION_MODE);

   //ESP8266 connect to router
   user_set_station_config();

}

gustavo
Posts: 24
Joined: Thu Apr 28, 2016 6:01 pm

Re: ESP8266 as TCP SSL client

Postby gustavo » Mon Aug 08, 2016 5:41 pm

When will this be available on the RTOS SDK?

Dashaduamp
Posts: 5
Joined: Mon Jun 19, 2017 10:28 am

ESP8266 as TCP SSL client

Postby Dashaduamp » Tue Jun 20, 2017 4:10 pm

Dear Sir
I am Dushyant here
i have made Vb code for Modbus Tcp/Ip. Which works as Server/Slave as well as Client/Master.
Now my software can connect with only one server at one time
so is it possible to be connected for continusly with more then one server?

Bentjudges
Posts: 5
Joined: Wed Sep 27, 2017 5:26 pm

ESP8266 as TCP SSL client

Postby Bentjudges » Sun Oct 15, 2017 11:44 pm

Thanks for this post providing the SSl certificate authentication installation steps.

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