Daniel Law iDanielLaw

This example shows vxlan nat traversal, using UDP hole punching.

         +---------------+
         | (node5) vxlan |
         +---------------+
                  | uplink
       +--------------------+
       | (node4) masquerade |
 +--------------------+

Lava Lamp Random Number Generator

(extracted from the now defunct SGI project at http://lavarand.sgi.com/cgi-bin/how.cgi via the magical Internet Archive Wayback Machine)

Lava Lamps can be used as a source of randomness, which can be used to establish a random number generator. The output of the RNG can then be consumed by various computer applications.

Step 1: Establish a chaotic system

(Set up Lava Lite® lamps in a machine room.)

The netfilter hooks in the kernel and where they hook in the packet flow

The figure below calls out

The netfilter hooks
The order of table traversal

	#!/bin/bash
	# Create and sign a JWT token with ES256 given the path to an ECDSA
	# private key and a JSON payload.
	# $0 path/to/keypair.der '{"JSON": "payload"}'

	# Example keypair creation:
	# openssl ecparam -name prime256v1 -genkey -noout -outform DER > example-keypair.der

	# A few tips for generating the payload:
	# - Pipe raw strings through `jq --raw-input .` to encode them as

	# RS256
	# private key
	openssl genrsa -out rs256-4096-private.rsa 4096
	# public key
	openssl rsa -in rs256-4096-private.rsa -pubout > rs256-4096-public.pem

	# ES512
	# private key
	openssl ecparam -genkey -name secp521r1 -noout -out ecdsa-p521-private.pem
	# public key

	package main

	import (
	"encoding/json"
	"fmt"
	"log"
	"net"
	"os"
	"time"
	)

	package main

	import (
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"io"
	"log"
	)

	package main

	import (
	"bufio"
	"net"
	)

	type Client struct {
	incoming chan string
	outgoing chan string

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/netfilter_ipv4.h>
	#include <linux/skbuff.h>
	#include <linux/udp.h>
	#include <linux/ip.h>

	/* This function to be called by hook. */
	static unsigned int
	hook_func(unsigned int hooknum,