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
：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。
