rakelimit

README

Rakelimit

A multi-dimensional fair-share rate limiter in BPF, designed for UDP. The algorithm is based on Hierarchical Heavy Hitters, and ensures that no party can exceed a certain rate of packets. For more information please take a look at our blog post.

Usage

First we need to increase the optmem memory

sudo sysctl -w net.core.optmem_max=65536

To activate rakelimit create a new instance and provide a file descriptor and a rate limit that you think the service in question won't be able to handle anymore:

conn, err := net.ListenPacket("udp4", "127.0.0.1:0")
if err != nil {
    tb.Fatal("Can't listen:", err)
}
udpConn := conn.(*net.UDPConn)

// We don't want to allow anyone to use more than 128 packets per second
ppsPerSecond := 128
rake, err := New(udpConn, ppsPerSecond)
defer rake.Close()
// rate limiter stays active even after closing

That's all! The library now enforces rate limits on incoming packets, and it happens within the kernel.

Limitations

• no IPv6 (we're working on adding it)
• requires tweaking of optmem
• not tested in production

Documentation

Index

• type Rakelimit
  • func New(conn syscall.Conn, ppsLimit uint32) (*Rakelimit, error)
  • func (rl *Rakelimit) Close() error

Types

type Rakelimit

type Rakelimit struct {
	// contains filtered or unexported fields
}

Rakelimit holds an instance of a ratelimiter that can be applied on a socket

func New

func New(conn syscall.Conn, ppsLimit uint32) (*Rakelimit, error)

New creates a new Rakelimit instance based on the specified ppsLimit

func (*Rakelimit) Close

func (rl *Rakelimit) Close() error

Close cleans up resources occupied and should be called when finished using the structure