4G模块使用pppd拨号调试记录

1、配置linux内核

执行make menuconfig

1. 使能USB GSM配置
   
2. 使能所有ppp协议相关配置

然后编译后的内核烧到板子中。

2、交叉编译移植ppp拨号程序

下载路径：https://download.samba.org/pub/ppp/
下载最新版本的源码。解压后进入目录 使用交叉编译工具编译：make CC=XXX/arm-linux-gcc (xxx为交叉编译工具的路径)。编译后将./pppd/pppd 、./chat/chat 和
./pppdump/pppdump拷贝到linux板子的/bin路径下。

3、编写pppd配置脚本

新建/etc/ppp/peers 目录。
在/etc/ppp 目录下新建gprs-chat-connect文件：
TIMEOUT 15
ABORT ‘\nDELAYED\r’ //有以下几条命令出现 中断连接 （ABORT）
ABORT ‘\nBUSY\r’
ABORT ‘\nERROR\r’
ABORT ‘\nNO DIALTONE\r’
ABORT ‘\nNO CARRIER\r’
TIMEOUT 40
‘’ \rAT
OK AT+CPIN?
OK AT+CSQ
OK AT+COPS?
OK AT+CGATT?
OK ATS0=0
OK AT+CREG?
OK ATE0V1
OK AT+CGDCONT=1,“IP”,“CMNET”
OK ATD99**1#
CONNECT
在/etc/ppp/peers目录下新建gprsdial文件:
/dev/ttyUSB0 // 根据实际情况写上相应的设备名
115200
nocrtscts
modem
debug
nodetach
local
usepeerdns
noipdefault
defaultroute
user “cmnet”
0.0.0.0:0.0.0.0
connect ‘/bin/chat -s -v -f /etc/ppp/gprs-chat-connect’

然后执行pppd call gprsdial &
结果如下：
timeout set to 15 seconds
abort on (\nDELAYED\r)
abort on (\nBUSY\r)
abort on (\nERROR\r)
abort on (\nNO DIALTONE\r)
abort on (\nNO CARRIER\r)
timeout set to 40 seconds
send (^MATM)
expect (OK)
^M
OK
– got it
send (AT+CPIN?^M)
expect (OK)
^M
^M
+CPIN: READY^M
^M
OK
– got it
send (AT+CSQ^M)
expect (OK)
^M
^M
+CSQ: 30,99^M
^M
OK
– got it
send (AT+COPS?^M)
expect (OK)
^M
^M
+COPS: 0,0,“CHINA MOBILE”,7^M
^M
OK
– got it
send (AT+CGATT?^M)
expect (OK)
^M
^M
+CGATT: 1^M
^M
OK
– got it
send (ATS0=0^M)
expect (OK)
^M
^M
OK
– got it
send (AT+CREG?^M)
expect (OK)
^M
^M
+CREG: 0,1^M
^M
OK
– got it
send (ATE0V1^M)
expect (OK)
^M
^M
OK
– got it
send (AT+CGDCONT=1,“IP”,“CMNET”^M)
expect (OK)
^M
^M
OK
– got it
send (ATD99**1#^M)
expect (CONNECT)
^M
^M
CONNECT
– got it
Script /bin/chat -s -v -f /etc/ppp/gprs-chat-connect finished (pid 1137), status = 0x0
Serial connection established.
using channel 5
Using interface ppp0
Connect: ppp0 <–> /dev/ttyUSB0
Warning - secret file /etc/ppp/pap-secrets has world and/or group access
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xe0fe878> ]
rcvd [LCP ConfReq id=0xc <asyncmap 0x0> <magic 0x15f10999> ]
sent [LCP ConfAck id=0xc <asyncmap 0x0> <magic 0x15f10999> ]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0xe0fe878> ]
rcvd [LCP DiscReq id=0xd magic=0x15f10999]
rcvd [CHAP Challenge id=0x1 <9fd2a447617e9bd6861c135e6a7ab964>, name = “UMTS_CHAP_SRVR”]
Warning - secret file /etc/ppp/chap-secrets has world and/or group access
sent [CHAP Response id=0x1 <09d515be4ae4ad3763be463a8ce1bcbe>, name = “cmnet”]
rcvd [CHAP Success id=0x1 “”]
CHAP authentication succeeded
CHAP authentication succeeded
sent [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
sent [IPCP ConfReq id=0x1 <compress VJ 0f 01> <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [LCP ProtRej id=0xe 80 fd 01 01 00 0f 1a 04 78 00 18 04 78 00 15 03 2f]
Protocol-Reject for ‘Compression Control Protocol’ (0x80fd) received
rcvd [IPCP ConfReq id=0x0]
sent [IPCP ConfNak id=0x0 <addr 0.0.0.0>]
rcvd [IPCP ConfRej id=0x1 <compress VJ 0f 01>]
sent [IPCP ConfReq id=0x2 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [IPCP ConfReq id=0x1]
sent [IPCP ConfAck id=0x1]
rcvd [IPCP ConfNak id=0x2 <addr 10.83.11.4> <ms-dns1 211.136.17.107> <ms-dns2 211.136.20.203>]
sent [IPCP ConfReq id=0x3 <addr 10.83.11.4> <ms-dns1 211.136.17.107> <ms-dns2 211.136.20.203>]
rcvd [IPCP ConfAck id=0x3 <addr 10.83.11.4> <ms-dns1 211.136.17.107> <ms-dns2 211.136.20.203>]
Could not determine remote IP address: defaulting to 10.64.64.64
not replacing existing default route via 192.168.0.1
local IP address 10.83.11.4
remote IP address 10.64.64.64
primary DNS address 211.136.17.107
secondary DNS address 211.136.20.203
Script /etc/ppp/ip-up started (pid 1142)
Script /etc/ppp/ip-up finished (pid 1142), status = 0x0

看到分配到IP地址就说明拨号成功。
这时候只能ping通127.0.0.1本地ip，无法ping通外网（如：114.114.114.114）。这是没有将ppp0的网关地址添加到路由中。执行命令： route add default gw 10.64.64.64就可将其添加到路由中。IP地址可从ifconfig中获得：
此时还需再添加dns就可ping通公网域名了。

至此可算告一段落。PPP协议以及拨号相关的流程后续再慢慢学习。