基于Go Packet实现网络数据包的捕获与分析
原创基于Go Packet实现网络数据包的捕获与分析
原创
摘要
- Packet Capturing Overview
- What is Packet Capturing
- How can it be used
- What is libpcap
- Debug Tools: tcpdump & WinPcap & snoop
- What is BPF
- What is gopacket
What is Packet Capturing
Packet capture is a computer networking term for intercepting a data packet that is crossing or moving over a specific computer network.Once a packet is captured, it is stored temporarily so that it can be analyzed. The packet is inspected to help diagnose and solve network problems and determine whether network security policies are being followed.
Packet Capture Overview
How can it be used
- Development Testing & validating & Reverse engineer APP on API
- Network Administration Seeing what traffic goes on in background,Looking for malicious traffic on networkData capturing is used to identify security flaws and breaches by determining the point of intrusion.
- Troubleshooting Managed through data capturing, troubleshooting detects the occurrence of undesired events over a network and helps solve them. If the network administrator has full access to a network resource, he can access it remotely and troubleshoot any issues.
- Security defcon Wall of Sheep.Hackers can also use packet capturing techniques to steal data that is being transmitted over a network, like Stealing credentials.When data is stolen, the network administrator can retrieve the stolen or lost information easily using data capturing techniques.
- Forensics forensics for crime investigations.Whenever viruses, worms or other intrusions are detected in computers, the network administrator determines the extent of the problem. After initial analysis, she may block some segments and network traffic in order to save historical information and network data.
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What is libpcap
libpcap flow involving data copy from kernel to user space.
Debug Tools
tcpdump
tcpdump 是一个运行在命令行下的嗅探工具。它允许用户拦截和显示发送或收到过网络连接到该计算机的TCP/IP和其他数据包。它支持针对网络层、协议、主机、网络或端口的过滤，并提供and、or、not等逻辑语句来帮助你去掉无用的信息，从而使用户能够进一步找出问题的根源。可以使用BPF来限制tcpdump产生的数据包数量。
snoop
snoop uses both the network packet filter and streams buffer modules to provide efficient capture of packets from the network. Captured packets can be displayed as they are received, or saved to a file for later inspection.
promiscuous mode
抓包工具需要工作在promiscuous mode(混杂模式)（superuser）， 指一台机器的网卡能够接收所有经过它的数据流，而不论其目的地址是否是它。当网卡工作在混杂模式下时，网卡将来自接口的所有数据都捕获并交给相应的驱动程序。一般在分析网络数据作为网络故障诊断手段时用到，同时这个模式也被网络黑客利用来作为网络数据窃听的入口。
BPF
Berkeley Packet Filter，缩写BPF，是类Unix系统上数据链路层的一种接口，提供原始链路层封包的收发。BPF支持“过滤”封包，这样BPF会只把“感兴趣”的封包到上层软件，可以避免从操作系统内核向用户态复制其他封包，降低抓包的CPU的负担以及所需的缓冲区空间，从而减少丢包率。BPF的过滤功能是以BPF虚拟机机器语言的解释器的形式实现的，这种语言的程序可以抓取封包数据，对封包中的数据采取算术操作，并将结果与常量或封包中的数据或结果中的测试位比较，根据比较的结果决定接受还是拒绝封包。
BPF Overview
Go Packet
Find Devices
Decoding Packet Layers
Capture Packet Workflow
- Getting a list of network devices
- Capturing packets from a network device
- Analyzing packet layers
- Using Berkeley Packet Filters
Creating and Sending Packets
Application
- qisniff
- 新一代Ntopng网络流量监控—可视化和架构分析
- 基于网络抓包实现kubernetes中微服务的应用级监控
专题合辑：Network Engineering
原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。
如有侵权，请联系 cloudcommunity@tencent.com 删除。
原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。
如有侵权，请联系 cloudcommunity@tencent.com 删除。
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