Android——4.2 - 3G移植之路之 reference-ril .pppd 撥號上網 (三)
Android的RIL機制中的 reference-ril.c 即為廠商提供的驅動接口。這個驅動源代碼各個廠商都是有提供的，網上也有下載。我如今用的就是huawei wcdma的。最後編譯成libreference-ril.so。關於這個接口驅動在RIL中所扮演的角色可參考
Android——RIL 機制源代碼分析
android 4.2自帶pppd源代碼在/external/ppp/pppd中.相同，kernel中也是須要打開對point-to-point 的支持，在network support裏面.
撰寫不易,轉載請註明出處：http://blog.csdn.net/jscese/article/details/40340665
一.requestSetupDataCall:
這個就是在reference-ril.c 中的數據流量的request，上層的接口通過onRequest 的RIL_REQUEST_SETUP_DATA_CALL請求。這些在上面說到的源代碼分析裏有具體分析，這裏就僅僅從撥號連接分析。
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‘}; //初始化屬性數組。用於暫時存儲撥號的屬性變量
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]; //取傳進來的接入點 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); //發送接入點的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); //這個就是聯通3G上網須要撥的號碼 ATD*99***1# 獲取連接
}
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"); //假設上面的撥號AT指令成功返回，這裏就啟用之前定義好的一個pppd service 調用腳本去撥號獲取IP 等網絡參數
// 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) //監測 ip 地址的屬性值。這個值我放在 pppd撥號腳本裏面來進行設置，假設成功這裏就能監測到
{
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; //通過獲取到的 網絡屬性 設置這個responses 提供給上層
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 中啟動一個服務來調用pppd撥號，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上面的服務是用來開機啟動rild的，載入libreference-ril動態庫，
而且指定了通信port為串口 -d /dev/ttyUSB2，另外還有 -s 代表是socket設備 -p 代表回環接口
以下的就是pppd撥號的腳本服務了，用來啟動撥號腳本，而且指定數據port.
這個pppd_gprs 服務須要設置權限。由於我是在reference-ril裏面通過屬性啟動的 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 }
};設置用到的net.ppp1.* 的權限。
init.gprs-pppd 設置運行權限，/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：
貼出撥號腳本
#!/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"
另外在這個撥號腳本同文件夾下 /system/etc/ppp/ 須要設置和註銷ip等參數的腳本。一個在撥號成功時調用。一個在斷開網絡時調用：
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" ""
貼張聯通apn為 3gnet 的撥號log：
Android——4.2 - 3G移植之路之 reference-ril .pppd 撥號上網 (三)