BPFabric - Netlab

Description

A programmable dataplane using the eBPF instruction set.

Dependencies

Tested and working with

• Ubuntu 22.04.3 LTS - kernel 5.15.0-92-generic
• clang 14.0.0

Examples

Learning Switch

Description

Very simple (legacy) learning switch that learn the source mac address and associated input port. If the port is unknown the packet is flooded.

How-To

Run a mininet topology and install the learningswitch.o eBPF elf to the switches.

# Run the mininet topology with three switches and 4 hosts
cd mininet
sudo ./3sw_topo.py

# Run the interactive controller
cd controller
./cli.py
--------------------------------------------------------------------------------
    eBPF Switch Controller Command Line Interface - Netlab 2016
    Simon Jouet <simon.jouet@glasgow.ac.uk> - University of Glasgow
--------------------------------------------------------------------------------


Documented commands (type help <topic>):
========================================
help

Undocumented commands:
======================
EOF  connections

(Cmd) Connection from switch 00000001, version 1
Connection from switch 00000002, version 1
Connection from switch 00000003, version 1

(Cmd) connections

      dpid    version     connected at
==========  =========  ===============
  00000001          1    1467377575.33
  00000002          1    1467377575.37
  00000003          1     1467377575.4
==========  =========  ===============

(Cmd) 1 install ../examples/learningswitch.o
(Cmd) 2 install ../examples/learningswitch.o
(Cmd) 3 install ../examples/learningswitch.o

Try the connectivity in Mininet between the hosts

mininet> pingall
*** Ping: testing ping reachability
h1 -> h2 h3 h4
h2 -> h1 h3 h4
h3 -> h1 h2 h4
h4 -> h1 h2 h3
*** Results: 0% dropped (12/12 received)

Analyze the tables of the switches to see the ethernet addres to port mapping

# List the BPF tables available on switch 1
(Cmd) 1 tables
(Cmd)
     name    type    key size    value size    max entries
=========  ======  ==========  ============  =============
  inports    HASH           6             4            256
=========  ======  ==========  ============  =============

# List the entries in the inports table
(Cmd) 1 table inports list
(Cmd)
           Key       Value
==============  ==========
  000400000000    00000000
  000400000003    01000000
  000400000002    01000000
  000400000001    00000000
==============  ==========

Centralized Learning Switch

Description

A simple centralized switch that will delegate the mac address to port mapping to the controller if the destination is unknown.

How-To

Run a mininet topology and run the controller responsible to reply to the PacketIn events from the switches.

# Start the mininet topology
cd mininet
sudo ./3sw_topo.py

# Start the controller
cd controller
./simpleswitch.py
Connection from switch 00000001, version 1
Installing the eBPF ELF
Connection from switch 00000003, version 1
Installing the eBPF ELF
Connection from switch 00000002, version 1
Installing the eBPF ELF
2 333300000002 ba776cdc9a6b 0x86dd
1 333300000002 ba776cdc9a6b 0x86dd
0 333300000002 ba776cdc9a6b 0x86dd
1 333300000002 000400000000 0x86dd
Inserting entry in switch 2  000400000000 1
[...]

Building BPFabric for OpenWRT routers

More on the wiki at https://github.com/UofG-netlab/BPFabric/wiki/OpenWRT

Issues

• Error while compiling the examples /usr/include/linux/types.h:4:10: fatal error: 'asm/types.h' file not found
  • sudo ln -s /usr/include/x86_64-linux-gnu/asm/ /usr/include/asm
  • sudo apt-get install g++-multilib

Debugging

Disassembling eBPF

objcopy -I elf64-little -O binary --only-section=.text program.o program.bin
ubpf/bin/ubpf-disassembler program.bin program.asm
cat program.asm

Known Issues

• String relocation is not working properly. The symbol in the ELF file is not containing the offset to the string table preventing the relocation of the string.

Authors

• Simon Jouet (simon.jouet@glasgow.ac.uk)
• Dimitrios Pezaros (dimitrios.pezaros@glasgow.ac.uk)

Acknowledgements

• EPSRC EP/L026015/1: A Situtation-Aware Information Infrastructure