P4_Source_routing

Author	Chieh-Ting Chung
E-mail	sksksk1748@gmail.com

Memo

• P4 , Source_routing

Topic

• h1 的 packet 要送到 h2。但特別之處在於，Ethernet header 跟 IP header 中間加入了自己設計的 header,使用這個 header 與自己設計的 rule, 使 packet 能按照特殊 header 裡的 label(port) 決定 packet 傳送路線。
  • 

Algorithm

1. Use the port field in header srcRoute_t as a label for label routing
2. Modify the parser
3. Define to actions
   • label_output : match the label and forward the packet to the port
   • pop_label_output : remove header srcRoute_t and output to the port
4. Create a table for label routing (s1-runtime.json, s2-runtime.json)
5. Modify rules to forward the label 1 to h2

Requirements

• I assume Oracle VM VirtualBox. You have to install
  • P4 VM image Download
• Copy the latest exercise

  $ git clone https://github.com/p4lang/tutorials

Your ~/source_routing/ folder should look like this

source_routing
├── build/ #compile完才會產生
│   └── ...
├── logs/  #compile完才會產生
│   └── ...
├── pcaps/ #compile完才會產生
│   └── ...
├── solution/
│   └── ...
└── ...

Install

1. Add my github P4 source file source_routing.p4, s1-runtime.json, s2-runtime.json and s3-runtime.json to ~/tutorials/exercises/source_routing/

Testing

1. In your shell, run

   $ make stop
   $ make clean
   $ make run

2. You should now see a Mininet command prompt. Open two terminals for h1 and h2, respectively

   mininet> xterm h1 h2

3. Run receive.py in h2

   $ ./receive.py

4. Run sender.py in h1

   $ ./send.py 10.0.2.2

5. "Node:h1" key in 1

   Type space separated port nums or "q" to quit: 1

Result

• h1 key in 1

  • 
    • key in 的 1 ,就是特殊 header 的 Label, 所以 table rule match 的 port, 其實就是這邊 key in 的 1

    ---------------------------------------------------------------------------------
    | Ethernet | Label = 自己輸入要輸入的 port number (command line 輸入), bos=1 | IP |
    ---------------------------------------------------------------------------------
    

• h1 send h2 (出現下圖結果，表示 h2 成功收到 h1 的 packet)

  • 

• 檢查 packet 經過的 switch (使用 ~source_routing/pcaps 裡的 Wireshark)

  • 

• 可以看出 s1-eth1_out.pcap 跟 s2-eth2_out.pcap 都有收到 Protocol 是 0x1234 的 packet

  • 

Reference

• P4_lang/tutorials ... source_routing
• 【NTUST】 109.1 CS5146701 Lab2 , Pei-Li Sun PROFESSOR