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：ftp://ftp.samba.org/pub/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 *

* *

**************************

www.tvrofans.org! \' 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

]

sent [LCP ConfNak id=0x3 ]

rcvd [LCP ConfReq id=0x5

]

sent [LCP ConfAck id=0x5

]

Warning - secret file /etc/ppp/pap-secrets has world and/or group access

sent [PAP AuthReq id=0x1 user="beeline" password=]

rcvd [PAP AuthAck id=0x1 ""]

PAP authentication succeeded

sent [CCP ConfReq id=0x1 ]

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 ]

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 ]

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=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 ]

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！！