80端口复用：利用haproxy把http流量和ssh流量分别转发到web服务器和ssh服务器

我们实验室在学校里面有一台服务器，带一个公网ip，但是只开了一个80端口，22端口竟然不给开！！！这让我很是不爽。之前一直待学校里，不给开我忍忍就算了，最近搬到了个没有校园网的偏远地方，连不上实验室的服务器实在是不能忍。于是重新折腾之前安装在服务器上的haproxy。

安装教程网络上到处到有，我按照网上的教程安装好haproxy后，再按照知乎上的 https://www.zhihu.com/question/31528831 教程配置之后，发现只在80端口访问网站是可以，但是用svn客户端访问我服务器上的svn返回错误，好像是显示option选项不支持之类的，受到
http://siukwan.sinaapp.com/?p=960 这篇文章的启发，我觉得是在http的acl里面配置少了option选项，于是一口气把http所有的头选项都回到匹配项里，像这样子：

#GET POS(T) PUT DEL(ETE) OPT(IONS) HEA(D) CON(NECT) TRA(CE)
acl is_http req.payload(0,3) -m bin 474554 504f53 505554 44454c 4f5054 484541 434f4e 545241

于是把svn的问题解决了。

接下来是ssh的问题，直接在acl匹配字符串SSH，然后每次在本地连接80端口都是返回以下错误：

ssh_exchange_identification: Connection closed by remote host

而直接连接22端口却没有问题。在网上搜索这个错误都说是黑名单之类的错误，但是我觉得这里并不是这个原因。后来抓包研究了下ssh协议，觉得并不是所有ssh数据包开头都是字符串SSH，所以acl简单粗暴地认为只有以字符串SSH开头的包才转发到22端口是不对的，应该更加简单粗暴地把http以外的数据包都转发到22端口，于是我把转发到22端口的配置语句的if条件去掉，问题得以解决。

以下是完整的配置文件/etc/haproxy/haproxy.cfg，其中http和ssh功能是测试过的，https没有测试，不知道能不能用。22端口是ssh服务器，82端口是http服务器，都是从外网的80端口进行访问。

#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   http://haproxy.1wt.eu/download/1.4/doc/configuration.txt #
#---------------------------------------------------------------------

#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
# to have these messages end up in /var/log/haproxy.log you will
# need to:
#
# 1) configure syslog to accept network log events.  This is done
#    by adding the '-r' option to the SYSLOGD_OPTIONS in
#    /etc/sysconfig/syslog
#
# 2) configure local2 events to go to the /var/log/haproxy.log
#   file. A line like the following can be added to
#   /etc/sysconfig/syslog
#
#    local2.*                       /var/log/haproxy.log
#
log         127.0.0.1 local0
log         127.0.0.1 local1 notice

chroot      /var/lib/haproxy
pidfile     /var/run/haproxy.pid
maxconn     4000
user        haproxy
group       haproxy
daemon

# turn on stats unix socket
stats socket /var/lib/haproxy/stats

#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
mode                    http
log                     global
option                  httplog
option                  dontlognull
option http-server-close
option forwardfor       except 127.0.0.0/8
option                  redispatch
retries                 3
timeout http-request    10s
timeout queue           1m
timeout connect         10s
timeout client          1m
timeout server          1m
timeout http-keep-alive 10s
timeout check           10s
maxconn                 3000

#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
#frontend  main *:5000
#    acl url_static       path_beg       -i /static /images /javascript /stylesheets
#    acl url_static       path_end       -i .jpg .gif .png .css .js
#
#    use_backend static          if url_static
#    default_backend             app

#---------------------------------------------------------------------
# static backend for serving up images, stylesheets and such
#---------------------------------------------------------------------
#backend static
#    balance     roundrobin
#    server      static 127.0.0.1:4331 check

#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
#backend app
#    balance     roundrobin
#    server  app1 127.0.0.1:5001 check
#    server  app2 127.0.0.1:5002 check
#    server  app3 127.0.0.1:5003 check
#    server  app4 127.0.0.1:5004 check

frontend main
mode tcp
bind *:80
log global
option tcplog
log-format %ft\ %b/%s

tcp-request inspect-delay 3s
acl is_https req.payload(0,3) -m bin 160301
#GET POS(T) PUT DEL(ETE) OPT(IONS) HEA(D) CON(NECT) TRA(CE)
acl is_http req.payload(0,3) -m bin 474554 504f53 505554 44454c 4f5054 484541 434f4e 545241
#SSH
acl is_ssh req.payload(0,3) -m bin 535348
tcp-request content accept if is_http
tcp-request content accept if is_https
#tcp-request content accept if is_ssh
tcp-request content accept
use_backend https if is_https
use_backend http if is_http
#use_backend ssh if is_ssh
use_backend ssh

backend ssh
mode tcp
#server ssh01 127.0.0.1:22 maxconn 10 check inter 3s
timeout server 1h
server server-ssh :22

backend http
mode tcp
server ngx01 127.0.0.1:82 maxconn 10 check inter 3s

backend https
mode tcp
server ngx02 127.0.0.1:433 maxconn 10 check inter 3s