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Home Page IoT Platform (Deprecated) Developer Reference Equipment Development Guide C Link SDK Secure tunnel Example 3: Isolating application processes from remote logon processes Business process overview

Business process overview

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This topic uses the ./demos/tunnel_switch_demo.c demo file from the C Link software development kit (SDK) as an example to describe the business process and its logs when the business process is isolated from the remote logon process.

Business process flowchart

d

Procedure

  1. Initialize the remote logon tunnel switch module.

        /* Create an RA instance and initialize the default parameters internally. */
    void *tunnel_switch_handle = aiot_tunnel_switch_init();
    if (tunnel_switch_handle == NULL) {
        printf( "aiot_tunnel_switch_init failed\n");
        return -1;
    }

  2. Configure features.

    1. Associate the MQTT module. Ensure that the MQTT module is connected. For more information, see MQTT connection.

      2.     /* Configure the MQTT handle. The RA module subscribes to MQTT messages internally. */
    aiot_tunnel_switch_setopt(tunnel_switch_handle, AIOT_TSOPT_MQTT_HANDLE, mqtt_handle);

    2. Configure the message callback function.

      This function parses tunnel-related messages and synchronizes them with the O&M process.

      3.     /* Configure the message callback function. */
    aiot_tunnel_switch_setopt(tunnel_switch_handle, AIOT_TSOPT_RECV_HANDLER, demo_tunnel_switch_recv_handle);

  3. Request tunnel connection information.

    Note

    The requested tunnel information expires after seven days. For more information, see Remote logon to IoT Platform.

        /* The device actively requests to establish a tunnel. This tunnel is used only for remote logon. */
    aiot_tunnel_switch_request(tunnel_switch_handle);

  4. Send information to the O&M process using inter-process communication.

    The following example uses Linux message queues for inter-process communication. You can also use other inter-process communication methods.

    static void demo_tunnel_switch_recv_handle(void *handle, const aiot_tunnel_switch_recv_data_t *recv, void *userdata)
{
    demo_tunnel_info_t info;
    memset(&info, 0, sizeof(info));

    if(recv->operation != AIOT_TUNNEL_OPERATOPN_CLOSE) {
        /* Print the expiration time of the tunnel authentication. If the tunnel is about to expire, send a request in advance. */
        printf("tunnel %s, create time %"PRIu64" , will expired after %"PRIu64" seconds \r\n", recv->tunnel_id, recv->created_time, recv->expired_time);
    } else {
        printf("tunnel %s close , close reason %s \r\n", recv->tunnel_id, recv->close_reason);
    }

    info.operation = recv->operation;
    if(recv->tunnel_id != NULL) {
        memcpy(info.tunnel_id, recv->tunnel_id, strlen(recv->tunnel_id));
    }

    if(recv->host != NULL) {
        memcpy(info.host, recv->host, strlen(recv->host));
    }

    if(recv->port != NULL) {
        memcpy(info.port, recv->port, strlen(recv->port));
    }

    if(recv->path != NULL) {
        memcpy(info.path, recv->path, strlen(recv->path));
    }

    if(recv->token != NULL) {
        memcpy(info.token, recv->token, strlen(recv->token));
    }

    /* Send the tunnel operation and connection information to the tunnel business process. Inter-process communication can also be implemented by storing the information in a file. */
    demo_posix_sysmsg_send((char *)&info, sizeof(info));
}

Operational logs

  • Establishing an MQTT connection.

    [1644818817.044][LK-0313] MQTT user calls aiot_mqtt_connect api, connect
[1644818817.044][LK-032A] mqtt host: iot-test-*************.unify.aliyuncs.com
[1644818817.044][LK-0317] user name: tunnel_test_00**********LXZe
[1644818817.044][LK-0318] password: 89EF89F414F1369*******************B18B39A6B63A3EFB319A0C408
success to establish tcp, fd=3
local port: 35024
[1644818817.133][LK-1000] establish mbedtls connection with server(host='iot-test-************.unify.aliyuncs.com', port=[443])
[1644818817.144][LK-1000] success to establish mbedtls connection, (cost 45247 bytes in total, max used 47983 bytes)
[1644818817.611][LK-0313] MQTT connect success in 567 ms
AIOT_MQTTEVT_CONNECT

  • The tunnel switch module has been initialized.

    [1644818817.611][LK-0309] sub: /sys/a1******XZe/tunnel_test_001/secure_tunnel/notify
[1644818817.611][LK-0309] sub: /sys/a1******XZe/tunnel_test_001/secure_tunnel/proxy/request_reply
     
heartbeat response
suback, res: -0x0000, packet id: 2, max qos: 1
suback, res: -0x0000, packet id: 1, max qos: 1

  • Requesting tunnel connection information.

    [1644818817.611][LK-0309] pub: /sys/a1W*******XZe/tunnel_test_001/secure_tunnel/proxy/request

[LK-030A] > 7B 22 69 64 22 3A 31 30  30 30 2C 22 70 61 72 61 | {"id":1000,"para
[LK-030A] > 6D 73 22 3A 7B 7D 7D                             | ms":{}}

  • Replying with tunnel connection information.

    [1644818818.122][LK-0309] pub: /sys/a1******XZe/tunnel_test_001/secure_tunnel/proxy/request_reply

[LK-030A] < 7B 22 63 6F 64 65 22 3A  32 30 30 2C 22 64 61 74 | {"code":200,"dat
[LK-030A] < 61 22 3A 7B 22 73 63 68  65 6D 61 22 3A 22 77 73 | a":{"schema":"ws
[LK-030A] < 73 22 2C 22 70 61 74 68  22 3A 22 2F 74 75 6E 6E | s","path":"/tunn
[LK-030A] < 65 6C 2F 34 61 32 66 63  39 39 62 2D 38 32 66 39 | el/4a2f********9
[LK-030A] < 2D 34 36 65 65 2D 62 34  31 63 2D 34 63 36 30 31 | -46ee-b41c-4c601
[LK-030A] < 36 33 30 65 35 31 61 2F  64 65 73 74 22 2C 22 74 | 630e51a/dest","t
[LK-030A] < 6F 6B 65 6E 5F 65 78 70  69 72 65 22 3A 36 30 34 | oken_expire":604
[LK-030A] < 37 39 39 2C 22 74 75 6E  6E 65 6C 5F 69 64 22 3A | 799,"tunnel_id":
[LK-030A] < 22 34 61 32 66 63 39 39  62 2D 38 32 66 39 2D 34 | "4a2fc**********
[LK-030A] < 36 65 65 2D 62 34 31 63  2D 34 63 36 30 31 36 33 | 6ee-b41c-4c60163
[LK-030A] < 30 65 35 31 61 22 2C 22  70 61 79 6C 6F 61 64 5F | 0e51a","payload_
[LK-030A] < 6D 6F 64 65 22 3A 22 61  70 70 2D 70 72 6F 78 79 | mode":"app-proxy
[LK-030A] < 22 2C 22 70 6F 72 74 22  3A 34 34 33 2C 22 68 6F | ","port":443,"ho
[LK-030A] < 73 74 22 3A 22 69 6F 74  2D 73 65 63 75 72 65 2D | st":"iot-secure-
[LK-030A] < 74 75 6E 6E 65 6C 2D 68  7A 2D 70 72 65 2E 61 6C | tunnel-hz-pre.al
[LK-030A] < 69 79 75 6E 63 73 2E 63  6F 6D 22 2C 22 75 72 69 | iyuncs.com","uri
[LK-030A] < 22 3A 22 77 73 73 3A 2F  2F 69 6F 74 2D 73 65 63 | ":"wss://iot-sec
[LK-030A] < 75 72 65 2D 74 75 6E 6E  65 6C 2D 68 7A 2D 70 72 | ure-tunnel-hz-pr
[LK-030A] < 65 2E 61 6C 69 79 75 6E  63 73 2E 63 6F 6D 2F 74 | e.aliyuncs.com/t
[LK-030A] < 75 6E 6E 65 6C 2F 34 61  32 66 63 39 39 62 2D 38 | unnel/4a2*******
[LK-030A] < 32 66 39 2D 34 36 65 65  2D 62 34 31 63 2D 34 63 | 2f9-46ee-b41c-4c
[LK-030A] < 36 30 31 36 33 30 65 35  31 61 2F 64 65 73 74 22 | 601630e51a/dest"
[LK-030A] < 2C 22 74 6F 6B 65 6E 22  3A 22 32 30 39 34 65 61 | ,"token":"2094ea
[LK-030A] < 37 37 2D 34 32 61 38 2D  34 32 37 32 2D 38 63 38 | 77-42a8-4272-8c8
[LK-030A] < 65 2D 62 37 61 65 36 64  37 39 65 62 30 36 22 7D | e-b7**********6"}
[LK-030A] < 2C 22 69 64 22 3A 22 31  30 30 30 22 2C 22 6D 65 | ,"id":"1000","me
[LK-030A] < 73 73 61 67 65 22 3A 22  73 75 63 63 65 73 73 22 | ssage":"success"
[LK-030A] < 7D                                               | }               

[1644818818.122][LK-0000] tunnel_switch_topic_handler payload:{"code":200,"data":{"schema":"wss","path":"/tunnel/4a2f************ee-b41c-4c601630e51a/dest","tok
tunnel 4a2f***********46ee-b41c-4c601630e51a, create time 1644818818127 , will expired after 604799 seconds

  • Sending instructions using inter-process communication.

    send msgsnd 644
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