Hi3516如何连接Wifi（三）

    小伙伴们大家好，上一篇（Hi3516如何连接Wifi（二））介绍了用程序启动wap\_supplicant，也就是Wifi的Daemon。下一步就是如何向Daemon发信息，我们可以参考//applications/sample/camera/communication/wpa\_cli，他实现了连接Daemon、扫描热点、连接热点等功能。

    我们打开wpa\_cli\_sample.c文件，核心功能在于这几个函数：

• InitControlInterface：初始化
• TestScan：扫描周围热点
• TestNetworkConfig：连接到指定热点

首先看InitControlInterface函数，他先调用了wpa\_ctrl\_open函数，获取了用于发送命令的控制接口g\_ctrlConn，是一个类型为struct

wpa\_ctrl的结构体。又调用一遍wpa\_ctrl\_open打开了一个用于事件监控的控制接口g\_monitorConn。然后启动了事件监控的线程执行MonitorTask函数，这个监控线程不是必须，可以省略。

int InitControlInterface()
{
    g_ctrlConn = wpa_ctrl_open(WPA_IFACE_NAME); // create control interface for send cmd
    g_monitorConn = wpa_ctrl_open(WPA_IFACE_NAME); // create control interface for event monitor
    if (!g_ctrlConn || !g_monitorConn) {
        SAMPLE_ERROR("open wpa control interface failed.");
        return -1;
    }
    if (wpa_ctrl_attach(g_monitorConn) == 0) { // start monitor
        pthread_create(&g_wpaThreadId, NULL, MonitorTask, NULL); // create thread for read event
        return 0;
    }
    return -1;
}

然后我们来着重分析一下TestNetworkConfig函数。实际上就是一系列SendCtrlCommand向Daemon发送指令。

static void TestNetworkConfig(void)
{
    char networkId[20] = {0};
    size_t networkIdLen = sizeof(networkId);
    int ret = SendCtrlCommand("DISCONNECT", networkId, &networkIdLen);
    ret += SendCtrlCommand("ADD_NETWORK", networkId, &networkIdLen);
    if (ret != 0) {
        SAMPLE_ERROR("add network failed.");
        return;
    }
    SAMPLE_INFO("add network success, network id [%.*s]", networkIdLen, networkId);
    char reply[100] = {0};
    size_t replyLen = sizeof(reply);
    char cmd[200] = {0};
    sprintf_s(cmd, sizeof(cmd), "SET_NETWORK %.*s ssid \"example\"", networkIdLen, networkId);
    ret += SendCtrlCommand(cmd, reply, &replyLen);
    replyLen = sizeof(reply);
    sprintf_s(cmd, sizeof(cmd), "SET_NETWORK %.*s psk \"012345678\"", networkIdLen, networkId);
    ret += SendCtrlCommand(cmd, reply, &replyLen);
    replyLen = sizeof(reply);
    sprintf_s(cmd, sizeof(cmd), "ENABLE_NETWORK %.*s", networkIdLen, networkId);
    ret += SendCtrlCommand(cmd, reply, &replyLen);
    replyLen = sizeof(reply);
    ret += SendCtrlCommand("RECONNECT", reply, &replyLen);
    replyLen = sizeof(reply);
    if (ret == 0) {
        SAMPLE_INFO("network config success.");
        return;
    }
    sprintf_s(cmd, sizeof(cmd), "REMOVE_NETWORK %.*s", networkIdLen, networkId);
    SendCtrlCommand(cmd, reply, &replyLen);
    SAMPLE_ERROR("network config failed remove network [%.*s].", networkIdLen, networkId);
}

wpa\_supplicant定义了许多命令，常见的有：

• PING：心跳检测命令。客户端用它判断WPAS是否工作正常。WPAS收到”PING”命令后需要回复“PONG”。
• MIB：客户端用该命令获取设备的MIB信息。
• STATUS：客户端用该命令来获取WPAS的工作状态。
• ADD\_NETWORK：为WPAS添加一个新的无线网络。它将返回此新无线网络的id（从0开始）。注意：此network id非常重要，客户端后续将通过它来指明自己想操作的无线网络。
• SET\_NETWORK\<network id> \<variable> \<value>：network id是无线网络的id。此命令用于设置指定无线网络的信息。其中variable为参数名，value为参数的值。
• ENABLE\_NETWORK\<network id>：使能某个无线网络。此命令最终将促使WPAS发起一系列操作以加入该无线网络。
• SCAN： 扫描附近AP
• SCAN\_RESULT：列出最近一次扫描的结果
• LIST\_NETWORKS： 列出添加的所有AP

看完上边就很好理解了，先是DISCONNECT断开已有连接，ADD\_NETWORK添加一个新的无线网络，SET\_NETWORK设置ssid和psk，ENABLE\_NETWORK使能这个无线网络，最后一个RECONNECT重新连接有点迷，去掉应该也没关系，不过本人没有尝试。
    TestScan函数就留给读者自行分析。

    了解了这些，我们就可以在自己的代码中去连接WIFI热点了，我是放在了ACE模块IDE自建module中，这样就可以在JS中调用了。还可以传递ssid和psk参数，连接指定的热点。如果需要，也可以增加扫描热点并获得热点列表的功能。

    在移植的过程中，需要注意的是，BUILD.gn文件需要增加相关配置，头文件目录增加：

    "//third\_party/wpa\_supplicant/wpa\_supplicant-2.9/src/",

依赖项deps增加：

    "//third\_party/wpa\_supplicant/wpa\_supplicant-2.9:wpa\_supplicant",

ldflags选项增加"-lwpa\_client"。

    这样应该就可以正常编译了。

    运行后观察日志输出，有点多：

01-01 00:01:32.597 11 60 D 03B00/JS-3RD-APP: [Console Debug] Connecting to ap: huaweim20
01-01 00:01:32.597 11 60 I 03900/ACE: ConnectToWifi invoked!
01-01 00:01:32.597 11 60 I 03900/ACE: ssid: huaweim20
 WpaCliSample(DumpString:584):  SendCtrlCommand raw return dump start.
OK

 WpaCliSample(DumpString:589):  SendCtrlCommand raw return dump end.
01-01 00:01:32.597 11 60 I 03900/ACE: psk: huaweim20
 WpaCliSample(DumpString:584):  SendCtrlCommand raw return dump start.
1

 WpaCliSample(DumpString:589):  SendCtrlCommand raw return dump end.
 WpaCliSample(ConnectToWifiInner:717):  add network success, network id [1
]
01-01 00:01:32.597 11 60 I 03900/ACE: InitControlInterface
 WpaCliSample(DumpString:584):  SendCtrlCommand raw return dump start.
OK

 WpaCliSample(DumpString:589):  SendCtrlCommand raw return dump end.
01-01 00:01:32.623 11 60 I 03900/ACE: ConnectToWifiInner
 WpaCliSample(DumpString:584):  SendCtrlCommand raw return dump start.
OK

 WpaCliSample(DumpString:589):  SendCtrlCommand raw return dump end.
 WpaCliSample(DumpString:584):  SendCtrlCommand raw return dump start.
OK

 WpaCliSample(DumpString:589):  SendCtrlCommand raw return dump end.
 WpaCliSample(DumpString:584):  SendCtrlCommand raw return dump start.
OK

 WpaCliSample(DumpString:589):  SendCtrlCommand raw return dump end.
 WpaCliSample(ConnectToWifiInner:733):  network config success.
WIFI: Scan : (null) SSID : 0

[HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=15, ret=0
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=5
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=5
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=5
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=5
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=5
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=4
WifiWpaDriverEventProcess event=5
WifiWpaEventScanResultProcess: ie_len=248, beacon_ie_len=248
WifiWpaEventScanResultProcess done
WifiWpaDriverEventProcess event=5
WifiWpaEventScanResultProcess: ie_len=310, beacon_ie_len=310
WifiWpaEventScanResultProcess done
WifiWpaDriverEventProcess event=5
WifiWpaEventScanResultProcess: ie_len=226, beacon_ie_len=226
WifiWpaEventScanResultProcess done
WifiWpaDriverEventProcess event=5
WifiWpaEventScanResultProcess: ie_len=243, beacon_ie_len=243
WifiWpaEventScanResultProcess done
WifiWpaDriverEventProcess event=5
WifiWpaEventScanResultProcess: ie_len=198, beacon_ie_len=198
WifiWpaEventScanResultProcess done
WifiWpaDriverEventProcess event=4
WifiWpaGetScanResults2 done
WifiWpaEventScanDoneProcess done
wlan0: Trying to associate with bc:e2:65:3c:19:70 (SSID='huaweim20' freq=2462 MHz)
[97854][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
[E]oal_exception_submit, g_pst_exception_info is null
[97859][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
[E]oal_exception_submit, g_pst_exception_info is null
[HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=17, ret=0
WifiWpaAssociate done ret=0
[97876][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
[E]oal_exception_submit, g_pst_exception_info is null
[97887][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
[E]oal_exception_submit, g_pst_exception_info is null
[97897][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
[E]oal_exception_submit, g_pst_exception_info is null
[97907][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
[E]oal_exception_submit, g_pst_exception_info is null
[97917][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
[E]oal_exception_submit, g_pst_exception_info is null
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=13
[97931][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
WifiWpaDriverEventProcess event=13[E]oal_exception_submit, g_pst_exception_info is null

[97944][E:1786]{oal_sdio_transfer_scatt::write failed=-84}
WifiWpaDriverEventEapolRecvProcess call[E]oal_exception_submit, g_pst_exception_info is null

[ERR]
 l2_packet_receive1
 [HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=6

 l2_packet_receive2
 [HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=6, ret=0

 l2_packet_receive3

 rx_callback
 WifiWpaReceiveEapol done
WifiWpaDriverEventProcess event=6
wlan0: Associated with bc:e2:65:3c:19:70
[HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=5, ret=0
WifiWpaWpaSendEapol done ret=0
wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
WifiWpaEventConnectResultProcess done
[ERR][HDF:E/HDF_LOG_TAG]HdfWifiSendEvent event=13
WifiWpaDriverEventProcess event=13
WifiWpaDriverEventEapolRecvProcess call

 l2_packet_receive1

 l2_packet_receive2
 [HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=6, ret=0

 l2_packet_receive3

 rx_callback
 [HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=5, ret=0
WifiWpaWpaSendEapol done ret=0
[HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=1, ret=0
[HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=3, ret=0
[HDF:I/HDF_LOG_TAG]WifiWpaCmdBlockSyncSend: cmd=1, ret=0
wlan0: WPA: Key negotiation completed with bc:e2:65:3c:19:70 [PTK=CCMP GTK=CCMP]
wlan0: CTRL-EVENT-CONNECTED - Connection to bc:e2:65:3c:19:70 completed [id=1 id_str=]
WifiWpaReceiveEapol done
[ERR][HDF:E/NetDeviceLite]LiteNetDhcpIsBound fail, ret = -5!
[ERR][HDF:E/NetDeviceLite]LiteNetDhcpIsBound fail, ret = -5!

    能清楚的看到SendCtrlCommand的过程。最后看到wlan0: CTRL-EVENT-CONNECTED，就是连接成功了。同时手机热点已连接设备数显示为1。

    稍后，我会做一个带有界面的视频Demo，展示效果。

作者：老船夫
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