Packetbeat协议扩展开发教程(1)

作者: medcl   发布时间:2015-12-30
Packetbeat(https://www.elastic.co/products/beats/packetbeat
是一个开源的网络抓包与分析框架,内置了很多常见的协议解析,如HTPP、MySQL、Thrift等。但是网络协议有很多,如何扩展一个自己的协议呢,本文将为您介绍如何在Packetbeat基础上扩展实现您自己的协议。

开发环境:
1.Go语言
Packetbeat是由Go语言编写,具有高性能和易部署的特点,有关Go语言的更多信息请访问:https://golang.org/
2.Git
源码管理,相信大家都比较熟悉了。
3.Tcpdump
*nix下的抓包分析,可选,用于调试。
4.Mac本一台
Windows太伤,不建议。
5.IDE
推荐idea,其它只要你顺手都行。

这个教程给大家介绍的是编写一个SMTP协议的扩展,SMTP就是我们发邮件使用的协议,加密的比较麻烦,为了方便,本教程使用不加密的名文传输的SMTP协议,默认对应端口是25。

A.源码签出
登陆Github打开https://github.com/elastic/beats 

fork后得到你自己的仓库,比如我的:https://github.com/medcl/packetbeat 
#创建相应目录
mkdir -p $GOPATH/src/github.com/elastic/ 
cd $GOPATH/src/github.com/elastic

#签出源码
git clone https://github.com/elastic/beats.git
cd beats

#修改官方仓库为upstream源,设置自己的仓库为origin源
git remote rename origin upstream
git remote add origin git@github.com:medcl/packetbeat.git

#获取上游最新的代码,如果是刚fork的话可不用管
git pull upstream master

#签出一个名为smtpbeat的分支,用于开发这个功能
git checkout -b smtpbeat

#切换到packetbeat模块
cd packetbeat

#获取依赖信息
(mkdir -p $GOPATH/src/golang.org/x/&&cd $GOPATH/src/golang.org/x &&git clone https://github.com/golang/tools.git )
go get github.com/tools/godep

#编译
make

编译出来的文件:packetbeat就在根目录
现在我们测试一下
修改etc/packetbeat.yml,在output下面的elasticsearch下面添加enabled: true,默认是不启用的,另外如果你的Elasticsearch安装了Shield,比如我的Elasticsearch的用户名和密码都是tribe_user,哦,忘了说了,我们的Elasticsearch跑在本机。
packetbeat.yml的详细配置可参见:https://www.elastic.co/guide/e ... .html 
output:
elasticsearch:
enabled: true
hosts: ["localhost:9200"]
username: "tribe_user"
password: "tribe_user"

现在可以运行命令启动packetbeat了,默认会监听所有内置的协议,如HTTP、DNS等。
./packetbeat -e -c etc/packetbeat.yml  -d "publish"

介绍一下常用的参数:
-N dry run模式,不实际output存储日志
-e 控制台输出调试日志
-d 仅显示对应logger的日志

好的,我们打开几个网页,控制台会有相应的输出,如下:
2015/12/29 14:24:39.965037 preprocess.go:37: DBG  Start Preprocessing
2015/12/29 14:24:39.965366 publish.go:98: DBG Publish: {
"@timestamp": "2015-12-29T14:24:39.709Z",
"beat": {
"hostname": "medcls-MacBook.local",
"name": "medcls-MacBook.local"
},
"bytes_in": 31,
"bytes_out": 115,
"client_ip": "192.168.3.10",
"client_port": 53669,
"client_proc": "",
"client_server": "",
"count": 1,
"direction": "out",
"dns": {
"additionals_count": 0,
"answers": [
{
"class": "IN",
"data": "www.a.shifen.com",
"name": "sp2.baidu.com",
"ttl": 333,
"type": "CNAME"
}
],
"answers_count": 1,
"authorities": [
{
"class": "IN",
"data": "ns1.a.shifen.com",
"expire": 86400,
"minimum": 3600,
"name": "a.shifen.com",
"refresh": 5,
"retry": 5,
"rname": "baidu_dns_master.baidu.com",
"serial": 1512240003,
"ttl": 12,
"type": "SOA"
}
],
"authorities_count": 1,
"flags": {
"authoritative": false,
"recursion_allowed": true,
"recursion_desired": true,
"truncated_response": false
},
"id": 7435,
"op_code": "QUERY",
"question": {
"class": "IN",
"name": "sp2.baidu.com",
"type": "AAAA"
},
"response_code": "NOERROR"
},
"ip": "192.168.3.1",
"method": "QUERY",
"port": 53,
"proc": "",
"query": "class IN, type AAAA, sp2.baidu.com",
"resource": "sp2.baidu.com",
"responsetime": 18,
"server": "",
"status": "OK",
"transport": "udp",
"type": "dns"
}
2015/12/29 14:24:39.965774 preprocess.go:94: DBG Forward preprocessed events
2015/12/29 14:24:39.965796 async.go:42: DBG async forward to outputers (1)
2015/12/29 14:24:40.099973 output.go:103: DBG output worker: publish 2 events

然后Elasticsearch应该就会有数据进去了,我们看看:
curl http://localhost:9200/_cat/indices\?pretty\=true -u tribe_user:tribe_user
yellow open packetbeat-2015.12.29 5 1 135 0 561.2kb 561.2kb

至此,packetbeat源码的build成功,我们整个开发流程已经跑通了,下一节正式开始介绍SMTP协议的扩展。

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