Android——4.2 - 3G移植之路之 reference-ril .pppd 拨号上网 (三)

Android的RIL机制中的 reference-ril.c 即为厂商提供的驱动接口。这个驱动源代码各个厂商都是有提供的，网上也有下载。我如今用的就是huawei wcdma的。最后编译成libreference-ril.so。关于这个接口驱动在RIL中所扮演的角色可參考Android——RIL 机制源代码分析

android 4.2自带pppd源代码在/external/ppp/pppd中.相同，kernel中也是须要打开对point-to-point 的支持，在network support里面.

撰写不易,转载请注明出处：http://blog.csdn.net/jscese/article/details/40340665

一.requestSetupDataCall:

这个就是在reference-ril.c 中的数据流量的request，上层的接口通过onRequest 的RIL_REQUEST_SETUP_DATA_CALL请求。这些在上面说到的源代码分析里有具体分析，这里就仅仅从拨号连接分析。

static void requestSetupDataCall(void *data, size_t datalen, RIL_Token t)

{

    const char *apn;

    char *cmd;

    int err;

    ATResponse *p_response = NULL;

    char ppp_dnses[(PROPERTY_VALUE_MAX * 2) + 3] = {'\0'}; //初始化属性数组。用于暂时存储拨号的属性变量

    char ppp_local_ip[PROPERTY_VALUE_MAX] = {'\0'};

    char ril_pppd_tty[PROPERTY_VALUE_MAX] = {'\0'};

    char ppp_dns1[PROPERTY_VALUE_MAX] = {'\0'};

    char ppp_dns2[PROPERTY_VALUE_MAX] = {'\0'};

    char ppp_gw[PROPERTY_VALUE_MAX] = {'\0'};

    char exit_code[PROPERTY_VALUE_MAX] = {'\0'};

    int n = 1;

    RIL_Data_Call_Response_v6 *responses = alloca(n * sizeof(RIL_Data_Call_Response_v6)); //使用的是ipv6

    apn = ((const char **)data)[2]; //取传进来的接入点 apn

    /*    ALOGD("jscese display in reference  APN == '%s' \n",apn);

     apn ="3gnet";*/

    ALOGD("[%s] jscese display in reference  APN '%s' ", __func__, apn);

#ifdef USE_TI_COMMANDS

    // Config for multislot class 10 (probably default anyway eh?

)

    err = at_send_command("AT%CPRIM=\"GMM\",\"CONFIG MULTISLOT_CLASS=<10>\"",

            NULL);

    err = at_send_command("AT%DATA=2,\"UART\",1,,\"SER\",\"UART\",0", NULL);

#endif /* USE_TI_COMMANDS */

    int fd, qmistatus;

    size_t cur = 0;

    size_t len;

    ssize_t written, rlen;

    char status[32] = {0};

    int retry = 10;

    const char *pdp_type;

    ALOGD("requesting data connection to APN '%s'", apn);

    pdp_type = "IP"; // jscese add for dial

    asprintf(&cmd, "AT+CGDCONT=1,\"%s\",\"%s\",,0,0", pdp_type, apn);

    //FIXME check for error here

    err = at_send_command(cmd, NULL); //发送接入点的AT指令

    free(cmd);

#if 0

    // Set required QoS params to default

    err = at_send_command("AT+CGQREQ=1", NULL);

    // Set minimum QoS params to default

    err = at_send_command("AT+CGQMIN=1", NULL);

    // packet-domain event reporting

    err = at_send_command("AT+CGEREP=1,0", NULL);

    // Hangup anything that's happening there now

    err = at_send_command("AT+CGACT=1,0", NULL);

#endif

    // Start data on PDP context 1

    if (strcmp(apn, "3gnet") == 0)

    {

        ALOGD("jscese display in reference  is 3gnet \n");

        err = at_send_command("ATD*99***1#", &p_response);  //这个就是联通3G上网须要拨的号码 ATD*99***1# 获取连接

    }

    else if (strcmp(apn, "ctnet") == 0)

    {

        ALOGD("jscese display in reference  is ctnet \n");

        err = at_send_command("ATD#777", &p_response);

    }

    if (err < 0 || p_response->success == 0)

    {

        goto error;

    }

    at_response_free(p_response);

    sleep(1); //Wait for the modem to finish

    property_set("net.ppp1.local-ip", "");

    property_set("net.gprs.ppp-exit", "");

    property_set("ctl.start", "pppd_gprs"); //假设上面的拨号AT指令成功返回，这里就启用之前定义好的一个pppd service 调用脚本去拨号获取IP 等网络參数

    // Dialup

    sleep(3);

    /*jscese add try 5 times to get ip*/

    int iRetry = 5;

    while (iRetry > 0)

    {

        property_get("net.gprs.ppp-exit", exit_code, "");

        if (strcmp(exit_code, "0") != 0)

        {

            ALOGE("PPPd exit with code %s", exit_code);

            iRetry = 0;

            break;

        }

        ALOGI("Waiting For Property");

        if (wait_for_property("net.ppp1.local-ip", NULL, 10) < 0) //监測 ip 地址的属性值。这个值我放在 pppd拨号脚本里面来进行设置，假设成功这里就能监測到

        {

            ALOGE("[%s]: wait for IP from ppp link at %d\n", __func__, iRetry);

        }

        else

        {

            ALOGI("[%s]: got IP from ppp link\r\n", __func__);

            break;

        }

        iRetry--;

    }

    if (iRetry <= 0)

    {

        ALOGE("[%s]: fail to get IP\r\n", __func__);

        goto error;

    }

    /*    if (wait_for_property("net.ppp1.local-ip", NULL, 10) < 0) {

     ALOGE("Timeout waiting net.ppp1.local-ip - giving up!\n");

     goto error;

     }*/

    property_get("net.ppp1.local-ip", ppp_local_ip, NULL);

    property_get("net.ppp1.dns1", ppp_dns1, NULL);

    property_get("net.ppp1.dns2", ppp_dns2, NULL);

    property_get("net.ppp1.gw", ppp_gw, NULL);

    sprintf(ppp_dnses, "%s %s", ppp_dns1, ppp_dns2);

    ALOGI("Got net.ppp1.local-ip: %s\n", ppp_local_ip);

    responses[0].status = 0;

    responses[0].suggestedRetryTime = -1;

    responses[0].cid = 1;

    responses[0].active = 2;

    responses[0].type = "PPP";

    responses[0].ifname = PPP_TTY_PATH;

    responses[0].addresses = ppp_local_ip;

    responses[0].dnses = ppp_dnses;

    responses[0].gateways = ppp_gw;  //通过获取到的 网络属性 设置这个responses 提供给上层

    RIL_onRequestComplete(t, RIL_E_SUCCESS, responses, n * sizeof(RIL_Data_Call_Response_v6));

    return;

    error: RIL_onRequestComplete(t, RIL_E_GENERIC_FAILURE, NULL, 0);

    at_response_free(p_response);

}

二.pppd

在上面 requestSetupDataCall 中启动一个服务来调用pppd拨号，先在init.rc中加入：

 #jscese add for usb_switch service when 3G dongle add for serial

service ril-daemon /system/bin/rild -l /system/lib/libreference-ril.so -- -d /dev/ttyUSB2

    class main

    socket rild stream 660 root radio

    socket rild-debug stream 660 radio system

    user root

    group radio cache inet misc audio log

service pppd_gprs /system/etc/ppp/init.gprs-pppd /dev/ttyUSB0

    user root

    group radio cache inet misc

    disabled

    oneshot

## end

上面的服务是用来开机启动rild的，载入libreference-ril动态库，

而且指定了通信port为串口 -d /dev/ttyUSB2，另外还有 -s 代表是socket设备 -p 代表回环接口

以下的就是pppd拨号的脚本服务了，用来启动拨号脚本，而且指定数据port.

这个pppd_gprs 服务须要设置权限。由于我是在reference-ril里面通过属性启动的在/system/core/init/property_service.c中加入例如以下：

struct {

    const char *service;

    unsigned int uid;

    unsigned int gid;

} control_perms[] = {

    { "dumpstate",AID_SHELL, AID_LOG },

    { "ril-daemon",AID_RADIO, AID_RADIO },

/*jscese add for pppd 3G*/

    { "pppd_gprs",AID_RADIO, AID_LOG },

/*end*/

     {NULL, 0, 0 }

};

struct {

    const char *prefix;

    unsigned int uid;

    unsigned int gid;

} property_perms[] = {

...

/*jscese add  pppd for 3G*/

    { "net.ppp1.",AID_RADIO,0 },

/*end*/

    { NULL, 0, 0 }

};

设置用到的net.ppp1.* 的权限。

init.gprs-pppd 设置运行权限，/system/core/include/private/android_filesystem_config.h中：

static struct fs_path_config android_files[] = {

...

/*jscese add for pppd */

    { 00777, AID_ROOT,      AID_SHELL,    "system/etc/init.gprs-pppd" },

/*    end*/

...

}

init.gprs-pppd：

贴出拨号脚本

#!/system/bin/sh

PPPD_PID=

USER=`/system/bin/getprop net.gprs.user`

PASSWORD=`/system/bin/getprop net.gprs.password`

/system/bin/setprop "net.gprs.ppp-exit" ""

/system/bin/pppd $1 115200 linkname datakey unit 1 crtscts usepeerdns noauth defaultroute noipdefault ipcp-accept-local ipcp-accept-remote ipcp-max-failure 30 lcp-echo-interval 5 lcp-echo-failure 30 modem dump debug kdebug 8

PPPD_EXIT=$?

PPPD_PID=$!

/system/bin/log -t pppd "pppd exited with $PPPD_EXIT"

/system/bin/setprop "net.gprs.ppp-exit" "$PPPD_EXIT"

另外在这个拨号脚本同文件夹下 /system/etc/ppp/ 须要设置和注销ip等參数的脚本。一个在拨号成功时调用。一个在断开网络时调用：

ip-up-datakey：

#!/system/bin/sh

case $1 in

    ppp1)

        /android/bin/iptables --flush;

        /android/bin/iptables --table nat --flush;

        /android/bin/iptables --delete-chain;

        /android/bin/iptables --table nat --append POSTROUTING --out-interface ppp0 -j MASQUERADE;

        /android/bin/iptables --append FORWARD --in-interface ppp1 -j ACCEPT;

        echo 0 > /proc/sys/net/ipv4/ip_forward;

        echo 1 > /proc/sys/net/ipv4/ip_forward;

        ;;

    ppp0)

    /system/bin/setprop "net.interfaces.defaultroute" "ppp1";

    ;;

esac

/system/bin/setprop "net.ppp1.dns1" "$DNS1"

/system/bin/setprop "net.ppp1.dns2" "$DNS2"

/system/bin/setprop "net.ppp1.local-ip" "$IPLOCAL"

/system/bin/setprop "net.ppp1.remote-ip" "$IPREMOTE"

/system/bin/setprop "net.ppp1.gw" "$IPREMOTE"

/system/bin/setprop "net.ppp1.if" "$IFNAME"

ip-down-datakey：

#!/system/bin/sh

case $1 in

    ppp1)

        echo 0 > /proc/sys/net/ipv4/ip_forward;

        ;;

esac

/system/bin/setprop "net.ppp1.dns1" ""

/system/bin/setprop "net.ppp1.dns2" ""

/system/bin/setprop "net.ppp1.local-ip" ""

/system/bin/setprop "net.ppp1.remote-ip" ""

/system/bin/setprop "net.ppp1.gw" ""

/system/bin/setprop "net.ppp1.if" ""

贴张联通apn为 3gnet 的拨号log：