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Monday 1 August 2016

Mono PAC

A minimal proxy auto config file generator based on ip range.
A PAC(Proxy auto-config) file generator working with fetched China IP range, which helps walk around GFW.
Mono generates a much smaller and faster PAC file than any other project does.
This PAC file is designed to be hosted on your Openwrt routers for your mobile device, which means the size and the efficiency have the highest priority. When it's hosted on your VPS with gzip or used on your computer, we don't care that things.
The minimal unit of the APNIC's IP allocation is 256, which means it's safe to do IP >> 8 on IP range data. If you use data from some otherthings, modify my codes first.

Installation

$ git clone https://github.com/blackgear/mono_pac.git

Usage

$ cd ./src
$ python ./make.py -h
usage: MonoPac [-h] [-b blackList] [-w whiteList] [-i ipList] -p proxyList
               [-m] [-o pacFile]

Mono Pac Generator

optional arguments:
  -h, --help    show this help message and exit
  -b blackList  Path of the black list
  -w whiteList  Path of the white list
  -i ipList     Path of the iprange list
  -p proxyList  Proxy parameter in the pac file
  -m            Use unicode compression
  -o pacFile    Path of the output pac file

Across the Great Firewall, we can reach every corner in the world.

$ python ./make.py -p "SOCKS5 192.168.1.1:1080;SOCKS 192.168.1.1:1080" -o ./proxy.pac
ONLY Python 2 is supported.
-m option reduce 45% file size with 2.8% extra efficiency loss, but it may cause some PAC management extensions like SwitchOmega crash.

Details

When you browse https://www.google.com/abc, The Pac works in this way:
              +-----------------------+
              |      Grab Host:       |
              |  Host=www.google.com  |
              +-----------------------+
                          |
                          v
              +-----------------------+
              | Domain=www.google.com |
              | Domain=google.com     |<-+
              | Domain=com            |  |
              +-----------------------+  |
                          |              |
                          v              |
         True +-----------------------+  |
   Proxy <----|If domain in blackList |  |
              +-----------------------+  |
                          |              |
                          v False        |
         True +-----------------------+  |
  Direct <----|If domain in whiteList |  |
              +-----------------------+  |
                          |              |
                          v False        |
              +-----------------------+  |
              |    If . in domain     |--+
              +-----------------------+
                          |
                          v False
              +-----------------------+
              |      Dns resolve      |
              +-----------------------+
                          |
                          v
         True +-----------------------+
  Proxy  <----|      If IP = nil      |
              +-----------------------+
                          |
                          v False
         True +-----------------------+
  Direct <----|   If IP = IPv6 addr   |
              +-----------------------+
                          |
                          v False
         True +-----------------------+
  Direct <----|    If IP in ipList    |
              +-----------------------+
                          |
                          v False
                        Proxy
When you browse http://127.0.0.1/index.html, The Domain will be 127.0.0.1, 0.0.1, 0.1, 1. Then dnsResolve will return 127.0.0.1.
dnsResolve return IPv4 only in IE and Chromium, dnsResolve can return IPv6 in Firefox.

Configs

All config files can use '#' as comments, all things behind '#' is ignored, space is automatic striped.
Config files like this is acceptable:
# Twitter
twitter.com
t.co
tweetdeck.com
twimg.com        # This domain is used for images
It will be prased as
twitter.com
t.co
tweetdeck.com
twimg.com

blackList:

One domains per line.

whiteList:

One domains per line.

ipList:

One record per line with IP/CIDR or IP/Wildcard format.
Both 100.100.100.0/24 and 100.100.100.0/255.255.255.0 are acceptable.

proxyList:

Proxy Configs separated by ";".
Available proxy configs:
PROXY host:port   = use HTTP proxy
SOCKS5 host:port  = use Socks5 proxy
DIRECT            = Do not use proxy
Example: PROXY 127.0.0.1:8080;DIRECT
Note: The latter config is the fallback of the former one. There is no limit on the length of the fallback list.
Note: Safari don't accept SOCKS5, use SOCKS instead, you can also use a more compatible form like: SOCKS5 host:port;SOCKS host:port, Safari will ignore the first config and use the second one.
Note: The DIRECT in the end have a potential risk cause the dns pollution affecting blackList domains.
Note: When you use socks proxy, whether dns resolve will through the proxy is determined by the Apps itself. When you use http proxy, the dns resolve will always through the proxy.

Performance

Test with Node.js:
$ node test.js
Testing pac generated by blackgear-mono_pac.pac
avg: 5.984us
Testing pac generated by blackgear-mono_pac-unicode.pac
avg: 6.152us
Testing pac generated by Leask-Flora_Pac-mod.pac
avg: 12.872us
Testing pac generated by usufu-Flora_Pac.pac
avg: 11.361us

$ ls -la *.pac
-rw-r--r--  1 Daniel  staff  165129 Feb 24 21:53 Leask-Flora_Pac-mod.pac
-rw-r--r--  1 Daniel  staff   16371 Jul 30 02:55 blackgear-mono_pac-unicode.pac
-rw-r--r--  1 Daniel  staff   29824 Jul 30 02:55 blackgear-mono_pac.pac
-rw-r--r--  1 Daniel  staff  254539 Feb 24 21:53 usufu-Flora_Pac.pac
MonoPac is the fastest and smallest PAC with full feature (blacklist, whitelist and full China IP range).
With the help of Unicode compress, the size become much smaller (30741 -> 17346).

Trivia

The PAC instance will be reuse instead of start new instance for every request. The code in the root scope of the PAC file will be run only once. The code in the FindProxyForURL function's scope will be run each time you browser the internet.
Just test this two PAC files:
    var unixtime_ms = new Date().getTime();
    while(new Date().getTime() < unixtime_ms + 5000) {}
    function FindProxyForURL(url, host) {
        return "DIRECT;";
    }

    function FindProxyForURL(url, host) {
        var unixtime_ms = new Date().getTime();
        while(new Date().getTime() < unixtime_ms + 5000) {}
        return "DIRECT;";
    }
So put all definations in the root scope will accelerate the PAC file.
from https://github.com/blackgear/mono_pac
------

最初可以依據 IP 和域名進行分流的實現是 proxy auto-config (PAC)，最初 PAC 是為瀏覽器設計的，但目前主流作業系統均有支持。PAC 實則是一個如 function FindProxyForURL(url, host) 的 JavaScript Function ，它的返回值是一個策略，可以為一個 HTTP Proxy 或 DIRECT。mono_pac 就是一個生成基於 IP 和域名分流的 PAC 的 Python 腳本。但 PAC 也並非一個完美的方式，首先，編輯分流策略需要懂得 JavaScript 語法，因此 PAC 還是常見分流方式的時候，網路上有很多生成 PAC 策略的開源項目。其次，有不少軟體不兼容 PAC，例如說自行實現了 HTTP 協議，或者是基於 TCP 實現的非 HTTP 協議，或者是 UDP 協議。這個問題常見於非瀏覽器程式，這類程式要麼只支持設置一個代理而不能實現分流，有的甚至不支持設置代理。
------

https://developer.mozilla.org/en-US/docs/Web/HTTP/Proxy_servers_and_tunneling/Proxy_Auto-Configuration_(PAC)_file
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