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wget http://pkgs.fedoraproject.org/repo/pkgs/ppp/ppp-2.4.7.tar.gz/78818f40e6d33a1d1de68a1551f6595a/ppp-2.4.7.tar.gz
tar zxvf ppp-2.4.7.tar.gz 
cd ppp-2.4.7
wget https://dev.openwrt.org/export/42525/trunk/package/network/services/ppp/patches/320-custom_iface_names.patch
patch -p 1 < 320-custom_iface_names.patch 
./configure 
make
make install

使用参数：

ifname pppoe1

OpenWRT安装PPPoe服务器，当客户端连接或断开时通过ip-down.d/ip-up.d执行ROS命令，ROS需配置使用SSH Key验证。
当系统拨号断开时停止PPPoe：

mkdir /etc/ppp/ip-down.d
cat >/etc/ppp/ip-down.d/pppoe-down.sh << EOF
#!/bin/sh
ssh admin@192.168.1.21 "/interface pppoe-client disable pppoe-out1"
EOF
chmod +x /etc/ppp/ip-down.d/pppoe-down.sh 

当连接系统拨号连接时开启PPPoe：

mkdir /etc/ppp/ip-up.d
cat >/etc/ppp/ip-up.d/pppoe-up.sh << EOF
#!/bin/sh
ssh admin@192.168.1.21 "/interface pppoe-client enable pppoe-out1"
EOF
chmod +x /etc/ppp/ip-up.d/pppoe-up.sh 

2015.03.17更新：
ros重新拨号只需enable就行，无需先disable：

ssh admin@192.168.1.21 "/interface pppoe-client enable pppoe-out1"

OpenWRT更新到14.07安装的pppoe不执行ip-down.d或up目录下脚本，需添加相应脚本，PPPD连接时会执行此脚本：

cat >/etc/ppp/ip-up << EOF
#!/bin/sh
[ -d /etc/ppp/ip-up.d ] && {
        for SCRIPT in /etc/ppp/ip-up.d/*
        do
                [ -x "$SCRIPT" ] && "$SCRIPT" "$@"
        done
}
EOF
chmod +x /etc/ppp/ip-up

OpenWRT安装PPPoe：

opkg update
opkg install rp-pppoe-server

配置PPPoe：

cat > pppoe-server-options << EOF
# PPP options for the PPPoE server
# LIC: GPL
require-chap
login
lcp-echo-interval 10
lcp-echo-failure 2
ms-dns 8.8.8.8
EOF

设置PPPoe账号、密码：

cat >/etc/ppp/chap-secrets << EOF
#USERNAME  PROVIDER  PASSWORD  IPADDRESS
www.haiyun.me * www.haiyun.me *
EOF

启动PPPoe服务脚本：

cat >/etc/init.d/pppoe-server << EOF
#!/bin/sh /etc/rc.common
# Copyright (C) 2006 OpenWrt.org
START=50

start() {
        echo 1 > /proc/sys/net/ipv4/ip_forward
        iptables -t nat -A POSTROUTING -s 10.0.1.0/24 -j MASQUERADE
        /usr/sbin/pppoe-server -k -T 60 -I eth1.1 -N 100 -L 10.0.1.1 -R 10.0.1.2
}

stop() {
        iptables -t nat -D POSTROUTING -s 10.0.1.0/24 -j MASQUERADE
    killall pppoe-server
}
EOF
chmod +x /etc/init.d/pppoe-server

遇到的问题1，客户端连接错误代码619，使用tcpdump监听数据包：

Generic-Error "RP-PPPoE: Child pppd process terminated"

查看pppoe错误日志：

May 26 13:31:07 OpenWrt daemon.notice pppd[4972]: Connect: ppp0 <--> /dev/pts/1
May 26 13:31:07 OpenWrt daemon.notice pppd[4972]: Modem hangup
May 26 13:31:07 OpenWrt daemon.notice pppd[4972]: Connection terminated.

解决方法：启动参数加-k，加载内核pppoe模块启动。
遇到的问题2，客户端连接错误代码691，原因：

用户名或密码填写错误
require-chap账号密码文件确认为chap-secrets

用ROS配置PPPOE服务器，连接 PPPOE服务器监听数据包如下：

07:50:52.398419 PPPoE PADI [Service-Name] [Host-Uniq 0x12150000]
07:50:52.398461 PPPoE PADO [Host-Uniq 0x12150000] [Service-Name] [AC-Name "MikroTik"] [Service-Name "pppoe"]
07:50:52.400079 PPPoE PADR [Service-Name] [Host-Uniq 0x12150000]
07:50:52.400120 PPPoE PADS [ses 0x12] [Host-Uniq 0x12150000] [Service-Name]
07:50:52.402604 PPPoE  [ses 0x12] LCP, Conf-Request (0x01), id 1, length 16
07:50:52.402611 PPPoE  [ses 0x12] LCP, Conf-Request (0x01), id 1, length 21
07:50:52.402611 PPPoE  [ses 0x12] LCP, Conf-Ack (0x02), id 1, length 16
07:50:52.403494 PPPoE  [ses 0x12] LCP, Conf-Ack (0x02), id 1, length 21
07:50:52.403502 PPPoE  [ses 0x12] CHAP, Challenge (0x01), id 1, Value 3cca193423b93a6e8b13609aa4209bf1, Name MikroTik
07:50:52.406462 PPPoE  [ses 0x12] LCP, Echo-Request (0x09), id 0, length 10
07:50:52.406467 PPPoE  [ses 0x12] LCP, Echo-Reply (0x0a), id 0, length 10
07:50:52.408030 PPPoE  [ses 0x12] CHAP, Response (0x02), id 1, Value 8fbdbac8f438f0c540fc21f801d0e6fe, Name user
07:50:52.408050 PPPoE  [ses 0x12] CHAP, Success (0x03), id 1, Msg Welcome.

PPPOE连接验证流程如下：

#https://www.haiyun.me
客户端开始连接发送广播包PADI寻找PPPOE服务器
PPPOE服务器接受到PADI广播包后，回复PADO注明主机名、服务类型。
客户端选择PPPOE服务器。
PPPOE服务器收到客户端发送的PADR消息后，给客户端分配会话ID并进行会话确认。
PPPOE服务器主动向客户端主动发起连接，发送一些随机字符串、id和PPPOE服务器的主机名作为连接信息。
客户端根据PPPOE服务器连接信息中字符串、id、主机名、账号密码计算出md5值发送给PPPOE服务器，同时明文发送账号。
PPPOE服务器确认验证信息是否正确，若正确定进行网络配置阶段，错误则断开链路。

使用迅雷下载的时候openwrt老是掉线，查看ppp日志：

May  5 07:02:05 OpenWrt daemon.info pppd[23813]: No response to 5 echo-requests
May  5 07:02:05 OpenWrt daemon.notice pppd[23813]: Serial link appears to be disconnected.
May  5 07:02:05 OpenWrt daemon.info pppd[23813]: Connect time 1089.9 minutes.
May  5 07:02:05 OpenWrt daemon.info pppd[23813]: Sent 335012468 bytes, received 1671352386 bytes.
May  5 07:02:06 OpenWrt user.notice root: stopping ntpclient
May  5 07:02:12 OpenWrt daemon.notice pppd[23813]: Connection terminated.
May  5 07:02:12 OpenWrt daemon.notice pppd[23813]: Modem hangup

PPPOE客户端会每隔10秒向服务器发送echo request确认在线，5次请求未回应就认为连线有问题并断开连接。
修改配置增加和ADSL服务器交互间隔：

vim /etc/ppp/options
lcp-echo-interval 30 #发送间隔秒
lcp-echo-failure 15 #15次未响应断开