arm中实现pppd连接GPRS上网的相关笔记，含GPRS自动拨号脚本（真正的实时监控,断线自动重拨）

在嵌入式Linux下GPRS上网方案

笔记1

硬/软件环境

基于S3C2410的嵌入式系统，COM1连接PC，COM2连接SIM300 GPRS模块。
该系统运行在Linux 2.6.14操作系统下，使用ppp套件通过SIM300进行PPP拨号。

一。让Linux内核支持PPP

进入Linux内核目录，执行#make menuconfig
Network Device Support à
       <*> PPP (point-to-point protocol) support
       [*]   PPP multilink support
       <*> PPP support for async serial ports
       <*> PPP support for sync tty ports
       <*> SLIP (serial line) support
       [*]   CSLIP compressed headers

二：ppp套件安装

?         下载ppp： ×最新版本为2.4.4
?         将ppp-2.4.4.tar.gz解压至目录
×这里默认ppp源码目录为$(PPP)
              #tar zxvf ppp-2.4.4.tar.gz
?         然后交叉编译ppp：
              #cd $(PPP)
#./configure
#make CC=/usr/local/arm/3.4.1/bin/arm-linux-gcc ×这里指定交叉编译器
?         将ppp套件安装至嵌入式系统中：
×这里默认可执行文件在嵌入式系统下的目录为$(EMB_BIN)
#cp $(PPP)/chat/chat $(EMB_BIN)
#cp $(PPP)/pppd/pppd $(EMB_BIN)
#cp $(PPP)/pppdump/pppdump $(EMB_BIN)
#cp $(PPP)/pppstats/pppstats $(EMB_BIN)
              ×这里默认嵌入式系统的etc目录为$(EMB_ETC)
              #mkdir $(EMB_ETC)/ppp
              #cp $(PPP)/etc.ppp/* $(EMB_ETC)/ppp

三：ppp套件配置

$(EMB_BIN)/dial-on.sh （GPRS启动脚本）

#!/bin/sh
#define dial_on function
dial_on()
{
       #test if pppd is running
       pppd_stat=`ifconfig|grep ppp|wc -l|cut -b 7-7`
       if [ $pppd_stat -gt 0 ]
       then
              echo "ppp connection's already started."
       else
              #close ethernet interface
              ifconfig eth0 down

              #ppp start
              pppd modem /dev/ttyS1 57600 nocrtscts lock connect "chat -v -f /etc/ppp/gprs-connect" user "" noauth debug defaultroute
              # pppd配置说明：
              # ttyS1：连接GPRS模块SIM300的串口
              # 57600：GPRS的拨号速率
              # nocrtscts：无流控
              # lock：锁定设备
              # connect “chat –v –f /etc/ppp/gprs-connect”：GPRS连接脚本文件
              # user “”：用户名，这里是无
              # noauth：无需认证
              # debug：输出调试信息
              # defaultroute：此拨号连接作为默认路由
              echo "ppp is starting..."
       fi
}

#dial on gprs
dial_on
#wait for ppp's init
sleep 5
pppd_stat=`ifconfig|grep ppp|wc -l|cut -b 7-7`
if [ $pppd_stat -eq 0 ]
then
       echo "trying 2nd time to call ppp"
       dial_on
       sleep 5
fi
pppd_stat=`ifconfig|grep ppp|wc -l|cut -b 7-7`
if [ $pppd_stat -eq 0 ]
then
       echo "pppd error!"
       echo "please check pppd's config files

$(EMB_BIN)/dial-off.sh （关闭GPRS连接脚本）

#!/bin/sh

#get pppd's pid
pid=`pidof pppd`

#if pppd process is running
if [ -n $pid ]
then
       #kill pppd
       kill $pid

       #open the ethernet interface
       ifconfig eth0 up

       echo "ppp connection is closed."
else
       echo "ppp connection isn't existed.

$(EMB_ETC)/ppp/gprs-connect （GPRS连接配置文件）

#GPRS连接超时设置
TIMEOUT      60
#若MODEM遇到BUSY、ERROR、NO CARRIER等信息时，停止拨号
ABORT   "BUSY"
ABORT   "ERROR"
ABORT   "NO CARRIER"
#外送“AT”指令
'' AT
#当得到“OK”回应时，外送AT+CGDCONT=1,"IP","CMNET"命令
"OK" "AT+CGDCONT=1,/042IP/042,/042CMNET/042"
#当得到“OK”回应时，外送ATDT*99***1#命令
"OK" "ATDT*99***1#"
#当得到“CONNECT”回应时，拨号结束，程序退出
"CONNECT"

$(EMB_ETC)/ppp/pap-secrets （GPRS认证配置文件）

# Secrets for authentication using PAP
# client    server     secret                    IP addresses
''      *     ''      *

说明

（1）还需要在$(EMB_ETC)/ppp目录下创建指向$(EMB_ETC)/resolv.conf的链接，用于指定PPP连接的DNS。
（2）在ppp连接时，需要关闭eth连接。在脚本中已经设置好了，首先关闭eth连接，然后进行ppp连接，在ppp连接完成时，再开启eth连接。
（3）最好在系统中开启syslogd进程，这样在/var/log/messages文件中会记录GPRS进行拨号的DEBUG信息，便于调试。
（4）运行拨号脚本后，可以使用#ifconfig查看PPP连接信息。

笔记2：

arm上成功实现ppp拨号的脚本：

ppp-on：

#!/bin/sh
pppd modem -d -detach lock /dev/ttySAC0 19200 kdebug 4 file /etc/ppp/options crtscts noipdefault netmask 255.255.255.0 defaultroute connect /etc/ppp/chat-script

ppp-off：

#!/bin/sh
######################################################################
#
# Determine the device to be terminated.
#
if [ "$1" = "" ]; then
 DEVICE=ppp0
else
 DEVICE=$1
fi

######################################################################
#
# If the ppp0 pid file is present then the program is running. Stop it.
if [ -r /var/run/$DEVICE.pid ]; then
        kill -INT `cat /var/run/$DEVICE.pid`
#
# If the kill did not work then there is no process running for this
# pid. It may also mean that the lock file will be left. You may wish
# to delete the lock file at the same time.
        if [ ! "$?" = "0" ]; then
                rm -f /var/run/$DEVICE.pid
                echo "ERROR: Removed stale pid file"
                exit 1
        fi
#
# Success. Let pppd clean up its own junk.
        echo "PPP link to $DEVICE terminated."
        exit 0
fi
#
# The ppp process is not running for ppp0
echo "ERROR: PPP link is not active on $DEVICE"
exit 1

chat-script：

#!/bin/sh
exec chat -v /
TIMEOUT 5 /
ABORT   "BUSY"  /
ABORT   "ERROR"  /
ABORT   "NO CARRIER" /
'' /rAT   /
OK  'AT+CGDCONT=1,"IP","CMNET"' /
OK  'ATDT*99***1#'  /
CONNECT ''  /

设置DNS的resove.conf：

nameserver 211.136.20.203
nameserver 211.136.17.107

笔记3：

GPRS自动拨号脚本（真正的实时监控,断线自动重拨）：

开机自动运行,实时监控,断线自动重拨
把文件传到DM里，设置文件属性为755，然后把启动路径加到init文件里即可 
原设置为5秒去检测一次，是以1字节去PING

#!/bin/sh
#请把dns1,dns2修改成拼得通的DNS,开机自动运行,实时监控,断线自动重拨
dns1="211.95.193.97"
dns2="211.136.20.203"
sleep 8
#/bin/pppd call gprs-siem &
sleep 12
while true
do
       ping -s 1 -c 1 $dns1    #去PING第一个DNS
       if [ "$?" != "0" ]      #假如PING不通
       then

           ping -s 1 -c 2 $dns2  #去PING第二个DNS
           if [ "$?" != "0" ]     #假如PING不通
           then
              killall pppd         #结束PPPD进程
              pppd call gprs-siem & #再去拨号
              sleep 12               #等待12秒
              sleep 5            #如果是PING  DNS2通的话就直接等待5秒
           fi
       else
              sleep 5            #如果是PING  DNS1通的话就直接等待5秒（一般要设置多长时间去PING请改这里）
       fi
done

代码简明！！它相当于在后台时时去PING一个DNS发现真正地掉线，它才会去重新拨号！！此版本经测试通过才发表。

**************************
*                        *
*   The Gemini Project   *
*                        *
**************************
! \' v1 Y# R2 P2 h: K
welcome on your dreambox! - Kernel 2.6.9 (08:14:21).

dreambox login: root

BusyBox v1.01 (2007.10.23-19:23+0000) Built-in shell (ash)
Enter 'help' for a list of built-in commands.

root@dreambox:~> /bin/sh /var/etc/ppp/aa
root@dreambox:~> AT
OK
ATZ
OK
ATH
OK
ATE1
OK
AT+CGDCONT=1,"IP","cmnet"( f$ m0 V3 U' o
OK
ATD*99***1#
CONNECT
Serial connection established.
using channel 2
Using interface ppp0
Connect: ppp0 <--> /dev/tts/0
Warning - secret file /etc/ppp/pap-secrets has world and/or group access
sent [LCP ConfReq id=0x1
]
rcvd [LCP ConfAck id=0x1
rcvd [LCP ConfReq id=0x3 <asyncmap 0xa0000> <pcomp> <accomp> <magic 0x2ab30537>
<auth chap MD5>]
sent [LCP ConfNak id=0x3 <auth pap>]
rcvd [LCP ConfReq id=0x5 <asyncmap 0xa0000> <pcomp> <accomp>
]
sent [LCP ConfAck id=0x5
<auth pap>]
Warning - secret file /etc/ppp/pap-secrets has world and/or group access
sent [PAP AuthReq id=0x1 user="beeline" password=<hidden>]
rcvd [PAP AuthAck id=0x1 ""]
PAP authentication succeeded
sent [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
sent [IPCP ConfReq id=0x1   ]
rcvd [LCP ProtRej id=0x6 80 fd 01 01 00 0f 1a 04 78 00 18 04 78]
sent [IPCP ConfReq id=0x1   ]
sent [IPCP ConfReq id=0x1   ]
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275420253.8 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss

round-trip min/avg/max = 275420253.8/275420253.8/275420253.8 ms
sent [IPCP ConfReq id=0x1   ]
sent [IPCP ConfReq id=0x1   ]
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275425386.3 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss9
round-trip min/avg/max = 275425386.3/275425386.3/275425386.3 ms
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275430517.7 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275430517.7/275430517.7/275430517.7 ms
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275435653.2 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275435653.2/275435653.2/275435653.2 ms
sent [IPCP ConfReq id=0x1   ]
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275440784.9 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275440784.9/275440784.9/275440784.9 ms
IPCP: timeout sending Config-Requests
sent [LCP TermReq id=0x2 "No network protocols running"]
rcvd [LCP TermAck id=0x2 "No network protocols running"]
Connection terminated.

Sending break to the modem

PDP context detached
Serial link disconnected.
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275445915.2 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275445915.2/275445915.2/275445915.2 ms
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275451048.9 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275451048.9/275451048.9/275451048.9 ms
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275456180.4 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275456180.4/275456180.4/275456180.4 ms
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275461314.4 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275461314.4/275461314.4/275461314.4 m
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275466446.2 ms
--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275466446.2/275466446.2/275466446.2 ms
PING 211.95.193.97 (211.95.193.97): 1 data bytes
9 bytes from 211.95.193.97: icmp_seq=0 ttl=244 time=275471577.9 ms

--- 211.95.193.97 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 275471577.9/275471577.9/275471577.9 ms
PING 211.95.193.97 (211.95.193.97): 1 data bytes

大家会问这样一直PING下去担心流量问题，浪费一些流量是垦定的，
不过我们是以1个字节去PING 加上返回的值一共是9个字节，也就是说5秒用9个字节
D1 U% ]& i
一个小时用9*12*60是一个小时6480字节=6。328125K
也就是说这样一个小时加6.33K的流量
大家还是担心的话可以改一下脚本，比如改60秒去PING一次啦，等等，都能有效去省流量！！

FROM:http://blog.csdn.net/seven407/article/details/4904877