phylake

probe kernel.function("tcp_send_challenge_ack") {
    printf("tcp_send_challenge_ack local=%s:%d remote=%s:%d\n", 
        format_ipaddr(tcpmib_local_addr($sk), AF_INET),
        tcpmib_local_port($sk),
        format_ipaddr(tcpmib_remote_addr($sk), AF_INET),
        tcpmib_remote_port($sk)
    );
}

phylake

About certificate formats

Encodings

• X.509 is expressed in the formal notation Abstract Syntax Notation One (ASN.1)
• Distinguished Encoding Rules (DER) is a binary encoding of ASN.1
• Privacy Enhanced Mail (PEM) is a base64 encoding of DER

.cer, .crt

A file with the extension .crt or .cer, contains a single X.509 certificate using

phylake

#!/bin/bash
# LC_CTYPE is for darwin
cat /dev/urandom | LC_CTYPE=C tr -cd 'a-f0-9' | head -c 32

phylake

Assignment in most other languages could be thought of as a stateful computation. For instance, when we do x = 5 in an imperative language, it will usually assign the value 5 to the variable x and it will also have the value 5 as an expression. If you look at that functionally, you could look at it as a function that takes a state (that is, all the variables that have been assigned previously) and returns a result (in this case 5) and a new state, which would be all the previous variable mappings plus the newly assigned variable.

http://learnyouahaskell.com/for-a-few-monads-more#state

phylake

package 
{
	import flash.display.Sprite;
	import flash.events.Event;
	
	/**
	 * 1. What will be printed to the console (via the trace statement)?
	 * 2. What is the value of this inside of nested()
	 */
	public class Main extends Sprite 

phylake

Replace all logical or assignment A ||= B with A || (A = B)

([^\s]+) \|\|= (.*);

$1 || ($1 = $2);

phylake

ifconfig | grep broadcast | arp -a

phylake

gem: --no-rdoc --no-ri

phylake

l = "xfbhlqtlj".split('').collect {|c| c[0] - 97}
k = [6,1,8,0,3,3,9,8,8]

l = l.zip(k).collect do |p|
   t = (p[0] - p[1]) % 26
   t += 97
   t.chr
end

p l.join('')

phylake

Internet Scale Services Checklist

A checklist for designing and developing internet scale services, inspired by James Hamilton's 2007 paper "On Desgining and Deploying Internet-Scale Services."

• http://mvdirona.com/jrh/talksandpapers/jamesrh_lisa.pdf

Basic tenets

• Does the design expect failures to happen regularly and handle them gracefully?
• Have we kept things as simple as possible?