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，这个驱动源码各个厂商都是有提供的，网上也有下载，我现在用的就是huawei wcdma的，最后编译成libreference-ril.so，关于这个接口驱动在RIL中所扮演的角色可参考 Android——RIL 机制源码分析
android 4.2自带pppd源码在/external/ppp/pppd中.同样，kernel中也是需要打开对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码分析里有详细分析，这里就只从拨号连接分析。
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，用于临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上网需要拨的号码 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"); //如果上面的拨号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 等网络参数
// 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) //监测 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，如果成功这里就能监测到
{
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中添加：
#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，加载libreference-ril动态库，
并且指定了通信端口为串口 -d /dev/ttyUSB2，另外还有 -s 代表是socket设备 -p 代表回环接口
下面的就是pppd拨号的脚本服务了，用来启动拨号脚本，并且指定数据端口.
这个pppd_gprs 服务需要设置权限，因为我是在reference-ril里面通过属性启动的 在/system/core/init/property_service.c中添加如下：
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 设置执行权限，/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目录下 /system/etc/ppp/ 需要设置和注销ip等参数的脚本，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：
