Daniel Law iDanielLaw

What is sync.Pool in golang and How to use it

sync.Pool (1/2)

Many Go libraries include custom thread-safe free lists, like this:

var objPool = make(chan *Object, 10)

func obj() *Object {

select {

Some examples of SNAT, DNAT with iptables with comments

mainly used in start-up script

How to test 'safely'

When we play with iptables aka firewall we might end up in situation, where we execute rule, which has unforseen impact - lock yourself out. Recovering from this situation is necessity.

How to:

Enable reboot via SMS.

Test all commands in shell first before putting them into Start-up script. This way the command will be wiped out, when unit is rebooted.

masquarade all outgoing packets to be WLAN0 IP

ESP8266 Web Server to storing ap config to EEPROM.

Original by chriscook8 from esp8266.com I just modified to use ESP8266WebServer library for easy to handle the http request.

This is sample code not yet complete.

Todo

when Wifi connected need to close the softAP.

	DEFAULT ramdisk
	LABEL ramdisk
	kernel /casper/vmlinuz
	append boot=casper initrd=/casper/initrd.img
	LABEL isotest
	kernel /casper/vmlinuz
	append boot=casper integrity-check initrd=/casper/initrd.img
	LABEL memtest
	kernel /install/memtest
	append -

	I'm capturing 802.11 frames - probe requests to be exact. I'm noticing occasional garbled data, so would to incorporate the Frame Check Sequence (FCS) to ensure frame integrity. I'd expect the card to dump failed checksum frames, but maybe this doesn't happen in promisc mode. We can see the FCS in action with tshark like so:

	# tshark -i mon0 -R 'wlan.fcs' -T fields -e wlan.fcs_good -e wlan.fcs
	1 0x5c1eecd5
	0 0x8d425ccf
	1 0xb28bb592
	1 0xd2cb1bf6

	...where wlan.fcs is the calculated checksum, and wlan.fcs_good is the boolean of the result.

	#!/bin/bash

	if [ "$4" == "" ]; then
	echo "usage: $0 <local_ip> <remote_ip> <new_local_ip> <new_remote_ip>"
	echo "creates an ipsec tunnel between two machines"
	exit 1
	fi

	SRC="$1"; shift
	DST="$1"; shift

	function construct(constructor, args) {
	function F() {
	return constructor.apply(this, args);
	}
	F.prototype = constructor.prototype;
	return new F();
	}
	// Sanboxer
	function sandboxcode(string, inject) {
	"use strict";

	package main

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

	package main

	import (
	"bytes"
	"encoding/gob"
	"fmt"
	)

	type MyFace interface {
	A()

	/// <reference path="../tsd/tsd.d.ts" />

	import mongoose = require('mongoose');
	import passport = require('passport');

	interface IUser extends mongoose.Document {
	provider: string;
	id: string;
	authorId: string;
	displayName: string;