util.go

package main

import (
	"bytes"
	"encoding/binary"
	"net"

	"github.com/hashicorp/go-msgpack/codec"
)

// getOutboundIP() preferred outbound ip of this machine
func getOutboundIP() (net.IP, error) {
	conn, err := net.Dial("udp", "8.8.8.8:80")
	defer conn.Close()
	if err != nil {
		return nil, err
	}
	localAddr := conn.LocalAddr().(*net.UDPAddr)
	return localAddr.IP, nil
}

// Decode reverses the encode operation on a byte slice input
func decodeMsgPack(buf []byte, out interface{}) error {
	r := bytes.NewBuffer(buf)
	hd := codec.MsgpackHandle{}
	dec := codec.NewDecoder(r, &hd)
	return dec.Decode(out)
}

// Encode writes an encoded object to a new bytes buffer
func encodeMsgPack(in interface{}) (*bytes.Buffer, error) {
	buf := bytes.NewBuffer(nil)
	hd := codec.MsgpackHandle{}
	enc := codec.NewEncoder(buf, &hd)
	err := enc.Encode(in)
	return buf, err
}

// Converts bytes to an integer
func bytesToUint64(b []byte) uint64 {
	return binary.LittleEndian.Uint64(b)
}

// Converts a uint to a byte slice
func uint64ToBytes(u uint64) []byte {
	buf := make([]byte, 8)
	binary.LittleEndian.PutUint64(buf, u)
	return buf
}