运动会没课，正好有时间，用shell脚本重写了一下之前的python自动登录脚本，这次写死了一些在北工大校园网内不会变的值，比原来完全python爬虫模拟的方式大幅简化，并且能够自动判断WiFi和有线网，同样支持IPv6登录（默认不启用）。
github地址：https://gist.github.com/WuSiYu/edb10f958cdfecc28688f02e0ec83deb
使用很简单，在后面加入用户名和密码即可，有线无线会自动判断。默认下，有线以“ipv4认证”登录，WiFi正常登录：
./bjut-autologin.sh <user> <password>设置LOGIN_IPV6环境变量后，将启用ipv6登录，此时有线以“ipv4与ipv6统一认证”，WiFi下会在正常登录后再到lgn6.bjut.edu.cn进行“ipv6认证”，在WiFi下会导致多占用一个session，一共占用两个session（都9102年了还限制2 session登录的学校是屑）。而有线因为有“统一认证”，所以还是一个session：
LOGIN_IPV6=1 ./bjut-autologin.sh <user> <password>同时本脚本还有“一键登出”的功能，在脚本后面加上-l或--logout即可，有线无线同样是自动判断：
./bjut-autologin.sh -l本脚本仅依赖curl，在openwrt上可能需要手动安装一下。不过就算用自带的wget，还是得手动装https的支持（在某工大不隔离的大内网下用http的理智程度大概并不高），所以综合来讲还是curl比较划算。
脚本内容
#!/bin/sh
# Copyright (c) 2019 SiYu Wu <wu.siyu@hotmail.com>
# BJUT gateway auto login script v0.1
# Usage: bjut-autologin.sh <user> <password>
# set LOGIN_IPV6=1 to enable ipv6 login, it will use one extra session on WiFi.
LOGIN_IPV6=${LOGIN_IPV6:-0}
if [ $# -ne 2 ] && !([ $# -eq 1 ] && ([[ $1 == '-l' ]] || [[ $1 == '--logout' ]]) ); then
echo "Usage: $0 <user> <password>"
echo " $0 -l, --logout"
echo " set LOGIN_IPV6=1 to enable ipv6 login, it will use one extra session on WiFi."
exit 1
fi
if [ $# -eq 1 ] && ([[ $1 == '-l' ]] || [[ $1 == '--logout' ]]); then
res=`curl -m 2 -s https://lgn.bjut.edu.cn/F.htm`
if [ `echo $res | grep -c 'Logout Error(no webmode)'` -eq 1 ]; then
echo 'WiFi connection detected'
res=`curl -m 2 -s https://wlgn.bjut.edu.cn/F.htm`
if [ `echo $res | grep -c 'Msg=14'` -eq 1 ]; then
echo '==> WiFi logout successful'
else
echo 'Error: WiFi logout failed!'
fi
elif [ `echo $res | grep -c 'Msg=14'` -eq 1 ]; then
echo '==> Wired logout successful'
else
echo 'Error: Wired logout failed!'
fi
exit 0
fi
lgn_code=`curl -m 2 -s -o /dev/null -w "%{http_code}" http://lgn.bjut.edu.cn`
if [ $lgn_code -eq 302 ]; then
echo 'WiFi connection detected'
res=`curl -m 2 -s --data "DDDDD=$1&upass=$2&6MKKey=%B5%C7%C2%BC+Login" https://wlgn.bjut.edu.cn`
if [ `echo $res | grep -c 'successfully logged in'` -eq 1 ]; then
echo '==> WiFi ipv4 login successful'
else
echo 'Error: WiFi ipv4 login failed!'
fi
if [ $LOGIN_IPV6 -ne 0 ]; then
res=`curl -m 2 -s --data "DDDDD=$1&upass=$2&v46s=2&v6ip=&f4serip=172.30.201.2&0MKKey=" https://lgn6.bjut.edu.cn/`
if [ `echo $res | grep -c 'successfully logged in'` -eq 1 ]; then
echo '==> WiFi ipv6 login successful'
else
echo 'Error: WiFi ipv6 login failed!'
fi
fi
elif [ $lgn_code -eq 200 ]; then
lgn_response=`curl -m 2 -s http://lgn.bjut.edu.cn`
if [ `echo $lgn_response | grep -c Balance` -eq 1 ]; then
echo "Error: Already logged in"
exit 2
else
echo 'Wired connection detected'
if [ $LOGIN_IPV6 -ne 0 ]; then
res=`curl -m 2 -s --data "DDDDD=$1&upass=$2&v46s=0&v6ip=&f4serip=172.30.201.2&0MKKey=" https://lgn6.bjut.edu.cn/V6?https://lgn.bjut.edu.cn`
v6ip=${res:419:39} # TODO: This implementation is not aesthetically pleasing due to compatibility with small systems without `sed` command.
res=`curl -m 2 -s --data "DDDDD=$1&upass=$2&0MKKey=Login&v6ip=$v6ip" https://lgn.bjut.edu.cn/`
if [ `echo $res | grep -c 'successfully logged in'` -eq 1 ]; then
echo '==> Wired ipv4+ipv6 login successful'
else
echo 'Error: Wired ipv4+ipv6 login failed!'
fi
else
res=`curl -m 2 -s --data "DDDDD=$1&upass=$2&v46s=1&v6ip=&f4serip=172.30.201.2&0MKKey=" https://lgn.bjut.edu.cn`
if [ `echo $res | grep -c 'successfully logged in'` -eq 1 ]; then
echo '==> Wired ipv4 login successful'
else
echo 'Error: Wired ipv4 login failed!'
fi
fi
fi
else
echo "Error: no connection to gateway"
exit 2
fi
exit 0
