Categories
Raspberry Pi

Raspberry Pi advanced photo frame

Intro

I am assembling a lot of different ideas I have to do some more cool things than was possible with my original Raspberry Pi photo frame effort although that contained a lot of original ideas as well.

Skillset

Intermediate or better linux skills required. Beginners/newbies: please do not attempt as you will encounter insurmountable problems and be left in a trail of tears. I don’t have time to help.

I will be using this remote control which I can attest is indeed compatioble with the RPi:

The inexpensive Rii remote controller with keyboard works with your Raspberry Pi

But it has no CTRL key! I can’t survive without that. It seems aimed at media consumers. I guess those types never need that key. At this point in time my idea is to use the arrow keys + Enter button as a familiar way to navigate around a simple menu I plan to create, plus perhaps the menu key. the pre-defined keys fbi has created for navigation are simply not intuitive, nor are they adequate for the tasks I have in mind.

Rii keyValue
up arrow103
down arrow108
right arrow106
left arrow105
Menu127
OK28
Some interesting keys and their values when monitored

In my basic photo frame approach I had a simpler rotate image python script. This python program below rotates pictures by the specified amount and preserves the EXIF tags. It doesn’t update the orientation tag after rotating because for the fbi display program I use that doesn’t matter. I call it rotate.py.

                    
#!/usr/bin/python3
# call with two arguments: degrees-to-rotate and filename
import PIL, os
import sys
from PIL import Image
# first do: pip3 install piexif
import piexif

degrees = int(sys.argv[1])
pic = sys.argv[2]

picture= Image.open(pic)
# see https://github.com/hMatoba/Piexif for piexif writeup
exif_dict = piexif.load(picture.info[“exif”])
exif_bytes = piexif.dump(exif_dict)
# both rotate and preserve EXIF data
picture.rotate(degrees,expand=True).save(“rot_” + pic,”jpeg”, exif=exif_bytes)

As it says in the code you need to install piexif in addition to Pillow:

$ sudo pip3 install Pillow && sudo pip3 install piexif

Example call

$ ./rotate.py 90 20160514_131528.jpg

Difficult problem

I set for myself a problem that is much more difficult than anything I’ve tackled. I wanted to post a preliminary solution, but I don’t want to do constant re-writes which are time-consuming. I have a lot of code re-writes to do. I do have a menu system working, and a couple functions implemented to date. But there is so much more to do to even get to an alpha version.

To be continued…

Pie-in-the-sky To-Do list

  • Use of deep learning AI to toss out images which are poor quality
  • Use Facebook API to identify people in the images
  • Commercialization of idea
  • Smarthome enablement, e.g., hey Alexa, pause that picture and tell me about it, etc

Breaking those pie-in-the-sky ideas down, I believe the RPi is way vastly underpowered to do any serious image analysis; Facebook facial recognition is creepy and an invasion of privacy; commercialization sounds great on paper but in reality is a time sink doing unpleasant things for little or no profit in the end; and lastly Smarthome enablement is actually the most achievable and was my original thinking before I landed on the remote control. I may or may not get back to it one day.

References and related

A more basic approach to creating a Raspberry Pi – based photo frame is described here.

The Rii remote control I am using only cost $12! https://www.amazon.com/gp/product/B01CL3ZXGO/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

A great tutorial on the Pillow python package which I use for image processing: https://auth0.com/blog/image-processing-in-python-with-pillow/

The full documentation fills it out even more: https://pillow.readthedocs.io/en/stable/

The official Exif documentation is here: http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf . For instance, page 42 says UserComments get the Tag ID 37510.

Categories
Linux Raspberry Pi

How to create a software keyboard

Intro

This example will probably get used in my advanced Raspberry Pi photo frame treatment. I use image display software, fbi, which is designed to take key presses in order to take certain actions, such as, advance to the next picture, display information about the current picture, etc. qiv works similarly. But I am running an automated picture display, so no one is around to type into the keyboard. hence the need for software emulation of the physical keyboard. I’ve always believed it must be possible, but never knew how until this week.

I am not a python programmer, but sometimes you gotta use whatever language makes the job easier, and I only know how to do this in python, python3 specifically.

This will probably only make sense for Raspberry Pi owners.

Setup

I believe this will work best if your Raspberry Pi has only a keyboard and not a mouse hooked up because in that case your keyboard ought to be mapped to /dev/input/event0. But it’s easy enough to change that. To see whether your keyboard is /dev/input/event0 or /dev/input/event1 or some other, just cat one of those files and start typing. You should see some junk when you’ve selected the right /dev/input file.

The program

I call it keyinject.py.

                    
#!/usr/bin/python3
# inject a single key, acting like a software keyboard
# DrJ 12/20
import sys
from evdev import UInput, InputDevice, ecodes as e
from time import sleep
# set DEBUG = True to print out more information
DEBUG = False
sleepTime = 0.001 # units are secs
# dict of name mappings. key is how we like to enter it, value is what is after KEY_ in evdev ecodes
d = {
‘1’ : ‘1’,
‘2’ : ‘2’,
‘3’ : ‘3’,
‘4’ : ‘4’,
‘5’ : ‘5’,
‘6’ : ‘6’,
‘7’ : ‘7’,
‘8’ : ‘8’,
‘8’ : ‘8’,
‘9’ : ‘9’,
‘0’ : ‘0’,
‘a’ : ‘A’,
‘b’ : ‘B’,
‘c’ : ‘C’,
‘d’ : ‘D’,
‘e’ : ‘E’,
‘f’ : ‘F’,
‘g’ : ‘G’,
‘h’ : ‘H’,
‘i’ : ‘I’,
‘j’ : ‘J’,
‘k’ : ‘K’,
‘l’ : ‘L’,
‘m’ : ‘M’,
‘n’ : ‘N’,
‘o’ : ‘O’,
‘p’ : ‘P’,
‘q’ : ‘Q’,
‘r’ : ‘R’,
‘s’ : ‘S’,
‘t’ : ‘T’,
‘u’ : ‘U’,
‘v’ : ‘V’,
‘w’ : ‘W’,
‘x’ : ‘X’,
‘y’ : ‘Y’,
‘z’ : ‘Z’,
‘.’ : ‘DOT’,
‘,’ : ‘COMMA’,
‘/’ : ‘SLASH’,
‘E’: ‘ENTER’,
‘S’: ‘RIGHTSHIFT’,
‘C’: ‘LEFTCTRL’
}

# https://python-evdev.readthedocs.io/en/latest/tutorial.html
inputchars = sys.argv
ltrs = inputchars[1]
# get rid of program name

keybd = InputDevice(“/dev/input/event0”)

for ltr in ltrs:
ui = UInput.from_device(keybd, name=”keyboard-device”)
if DEBUG: print(ltr)
mappedkey = d[ltr]
key = “KEY_” + mappedkey
if DEBUG: print(key)
if DEBUG: print(e.ecodes[key])

ui.write(e.EV_KEY, e.ecodes[key], 1) # KEY_ down
ui.write(e.EV_KEY, e.ecodes[key], 0) # KEY_ up
ui.syn()
sleep(sleepTime)
ui.close()

And it gets called like this:

$ sudo ./keyinject.py my.injected.letters

or

$ sudo ./keyinject.py ./m2.plE

to run the m2.pl script in the current directory and have it behave as though it were launched from a console terminal. The “E” is the ENTER key.

Interesting observations

There really is no such thing as a separate “k” key and “K” key (lower-case versus upper-case). There is only a single key labelled “K” on a keyboard. It’s a physical layer versus logical layer type of thing. The k and K are characters.

In the above program I did some of the keys – the ones I will be needing, plus a few bonus ones. I do need the ENTER key, and I can’t think of a way to convey that to this program, so to send ENTER you would do

$ sudo ./keyinject.py ENTER

But I was able to have these characters represent themselves: . , / so that’s not bad.

Prerequisites

You will need pyhon3 version > 3.5, I think. And the evdev package. I believe you get that with

$ sudo pip3 install evdev

And if you don’t have pip3 you can install that with

$ sudo apt-get update python3-pip

Reading keyboard input

Of course the opposite of simulating key presses is reading what’s been typed from an actual keyboard. That’s possible too with this handy evdev package. The following program is not as polished as the writing program, but it gives you the feel for what to do. I call it evread.py.

                    
#!/usr/bin/python3
# https://python-evdev.readthedocs.io/en/latest/tutorial.html
import asyncio
from evdev import InputDevice, categorize, ecodes

dev = InputDevice(‘/dev/input/event0’)
# following line is optional – it takes away the keybd from fbi!
# there is also a dev.ungrab()
dev.grab()

async def helper(dev):
async for ev in dev.async_read_loop():
print(repr(ev))

loop = asyncio.get_event_loop()
loop.run_until_complete(helper(dev))

Note the presence of the dev.grab(). That permits your program to be the exclusive reader of keyboard input, shutting out fbi. It can be commented out if you want to share.

Conclusion

We have created an example program, mostly for Raspberry Pi, though easily adapted to other linux environments, that injects keyboard presses, via a python3 program, as though those keys had been typed by someone using the physical keyboard such that, graphics programs which rely on this, such as fbi or qiv (and probably others – vlc?), can be controlled through software.

We have also provided a basic python program for reading key presses from the actual keyboard. I plan to use these things for my advanced RPi photo frame project.

References and related

The python evdev tutorial is really helpful: https://python-evdev.readthedocs.iogeoh/en/latest/tutorial.html

Raspberry Pi advanced photo frame article does not exist yet. The basic RPi photo frame article is here.

Another piece to the puzzle is turning GPS coordinates into a town name. That brief write-up is here.

Categories
Linux Python Raspberry Pi

What I’m working on: a Raspberry Pi digital photo frame

Intro
The idea is that for a display kiosk let’s have a Raspberry Pi drive a display like one of those electronic picture frames. Power the thing up, perhaps plug in a flash drive, leave off the mouse and keyboard, but have a display attached, and get it to where it just automatically starts a slideshow without more fuss.

Some discarded options
Obviously this is not breaking new ground. you can find many variants of this on the Internet. An early-on approach that caught my eye is flickrframe. I read the source code to learn that at the end of the day it relies on the fbi program (frame buffer imageviewer). I thought that perhaps I could rip out the part that connects to Flickr but it seemed like too much trouble. At the end of the day it’s just a question of whether to use fbi or not.

Then there’s Raspberry Pi slideshow. That’s a quite good write-up. That’s using pqiv. I think that solution is workable.

But the one I’m focusing on uses qiv. You would have thought that pqiv would rely on qiv (quick image viewer) but it appears not to. So qiv is a separate install. qiv has lots of switches so it’s been written with this kind of thing in mind it seems.

What it looks like so far

#!/bin/sh
# -f : full-screen; -R : disable deletion; -s : slideshow; -d : delay <secs>; -i : status-bar;
# -m : zoom; [-r : ranomdize]
# this doesn't handle filenames with spaces:
##cd /media; qiv -f -R -s -d 5 -i -m `find /media -regex ".+\.jpe?g$"`
# this one does:
if [ "$1" = "l" ]; then
# print out proposed filenames
  cd /media; find . -regex ".+\.jpe?g$"
else
  sleep 5
  cd /media; find . -regex ".+\.jpe?g$" -print0|xargs -0 qiv -f -R -s -d 5 -i -m
fi

The idea being, why not make a slideshow out of all the pictures found on a flash drive that’s been inserted into the Pi? That’s how a standard picture frame works after all. It’s a very convenient way to work with it. That’s the aim of the above script.

Requirements update
OK. Well this happens a lot in IT. We thought we were solving one problem but when we finally spoke with the visual arts team they had something entirely different in mind. They want to mix in movies as well. fbi, pqiv or qiv don’t handle movies. I have mplayer and vlc from my playing around with Raspberry Pi camera. mplayer runs like a dog on the movie files I tried, perhaps one frame update every two seconds. After more searching around I came across omxplayer. That actually works pretty well. It on the other hand doesn’t seem up to the task of handling a mixed multimedia stream of stills and movies. But it did handle the two movies types we had: .mov and .mp4 movie files. omxplayer is written specifically for the Pi so it uses its GPU for frame acceleration. mplayer just seems to rely on the CPU which just can’t keep up on a high-def quality movie. So as a result omxplayer will only play through a true graphical console. It doesn’t even bother you to get your DISPLAY environment variable set up correctly – it’s just going to send everything to the head display.

Overheard recently
And when using my TV as display omxplayer put out the sound, too, perfectly synchronized and of high quality.

I was thinking if we should kludge stitching together qiv and omxplayer. You know letting one lapse and starting up the other to transition from a still to a movie, but I don’t know how to make the transition smooth. So i searched around yet some more and found pipresents. I believe it is a python framework around omxplayer. It’s pretty sophisticated and yet free. It’s actually aimed at museums and can include reactions to pressed buttons as you have at museum displays. So far we got the example media show to loop through – it demonstrates a high-quality short movie and a still plus some captions at the beginning.

Pipresents isn’t perfect however
I quickly found some problems with pipresents so I went the official route and posted them to the github site, not really knowing what to expect. The first issue is that you are not allowed to import .mov files! That makes no sense since omxplayer plays them. So I post this bug and that very same day the author emails me back and explains that you simply edit pp_editor.py line 32 and add .mov as an additional video file type! Sure enough, that did it. Then I found that it wasn’t downsampling my images. These days everyone has a camera or phone that takes mmulti-megapixel images far exceeding a cheap display’s 1280×1024 resolution. So you only see a small portion of your jpeg. I just assumed pipresents would downsample these large pictures because the other packages like qiv do it so readily. Again the same day the author gets back to me and says no this isn’t supported – in pipresents. But there is a solution: I should use pipresents-next! It’s officially in beta but just about ready for production release. I don’t think I’ll go that route but it’s always nice to know your package continues to be developed. I’ve written my own downsampler which I will provide later on.

Screen turns off
The pipresents has a command-line switch, -b, to prevent screen blanking. But I think in general it’s better to not use that switch and instead disable screen blanking in general.

$ sudo nano /etc/kbd/config
– change BLANK_TIME=30 to BLANK-TIME=0
– and change POWERDOWN_TIME=30 to POWERDOWN_TIME=0
$ sudo nano /etc/lightdm/lightdm.conf
– below the [SeatDefault] line create this line:
xserver-command=X -s 0 dpms

How to get started with PiPresents
$ wget https://github.com/KenT2/pipresents/tarball/master -O – | tar xz

There should now be a directory ‘KenT2-pipresents-xxxx’ in your home directory. Rename the directory to pipresents:

$ mv KenT2* pipresents

To save time make sure you have two terminal windows open on your Pi and familiarize yourself with how to cut and paste text between them. Then from the one window you can:

$ cd pipresents; more README.md

while you execute the commands you’ve cut and paste from that window into the other, e.g.,

$ sudo apt-get install python-imaging
etc.

What happens if you forget to install the unclutter package
Not much. It’s just that you will see a mouse pointer in the center of the screen which won’t go away, which is not desirable for black box operation.

Python image downsizing program
This is also known as downsampling. Amazingly, you really don’t find a simple example program like this when you do an Internet search, at least not amongst the first few hits. I needed a program to reduce the large images to the size of the display while preserving the aspect ratio. My display, a run-of-the-mill Acer v173, is 1280 x 1024 pixels. Pretty standard stuff, right? yet the Pi sees it as 1232 x 992 pixels! Whoever would have thought that possible? And with no possible option to change that (at least from the GUI). So just put in the appropriate values for your display. This program just handles one single image file. also note that if it’s a small picture, meaning smaller than the display, it will be blown up to full screen and hence will make a thumbnail image look pixelated. The match doesn’t distinguish small from large images but I fel that is fine for the most part. So without further chatting, here it is. I called it resize3.py:

import Image
import sys
# DrJ 2/2015
# somewhat inspired by http://www.riisen.dk/dop/pil.html
# image file should be provided as argument
# Designed for Acer v173 display which the Pi sees as a strange 1232 x 992 pixel display
# though it really is 1 more run-of-the-mill 1280 x 1024
 
imageFile = sys.argv[1]
im1 = Image.open(imageFile)
 
def imgResize(im):
# Our display as seen by the Pi is a strange 1232 x 992 pixels
    width = im.size[0]
    height = im.size[1]
 
# If the aspect ratio is wider than the display screen's aspect ratio,
# constrain the width to the display's full width
    if width/float(height) > 1232.0/992.0:
      widthn = 1232
      heightn = int(height*1232.0/width)
    else:
      heightn = 992
      widthn  = int(width*992.0/height)
 
    im5 = im.resize((widthn, heightn), Image.ANTIALIAS) # best down-sizing filter
 
    im5.save("resize/" + imageFile)
 
imgResize(im1)

As I am not proficient in python I designed the above program to minimize file handling. That I do in a shell script which was much easier for me to write. Together they can easily handle downsampling all the image files in a particular directory. I call this script reduce.sh:

#!/bin/sh
echo "Look for the downsampled images in a sub-directory called resize
echo "JPEGs GIFs and PNGs are looked at in the current directory
mkdir resize 2>/dev/null
ls -1 *jpg *jpeg *JPG *png *PNG *gif *GIF 2>/dev/null|while read file; do
  echo downsampling $file
# downsample the image file
  python ~/resize3.py "$file"
done

Stopping the slideshow
Sometimes you just need to stop the thing and that’s not so easy when you’ve got it in blackbox mode and running at startup.

If you’re lucky enough to have a keyboard attached to the Pi we found that

<Alt> F4

from the keyboard stops it.

No keyboard? We assigned Our Pi a static IP address and leave an ethernet cable attached to it. Then we put a PC on the same subnet and ssh to it, e.g., using putty or teraterm. Then we run this simple kill script, which I call kill.sh:

#!/bin/sh
pkill -f pipresents.py
pkill omxplayer

Digital photo frame projects morphs to museum-style kiosk display
At times I was tempted to throw out this pipresents software but we persisted. It has a different emphasis from a digital photo frame where you plug in a USB stick and don’t care about the order the pictures are presented to you. pipresents is oriented towards museums and hence is all about curated displays, where you’ve pored over the presentation order and selected your mix of videos and images. And in the end that better matched our requirements.

The manual is wanting for clarity
It’s nice that a PDF manual is included, but it’s a pain to read it to extract the small bits of information you actually need. Here’s what you mostly need to know. An unattended slideshow mixture of images and videos is what he calls a mediashow. Make your own profile to hold your mediashow:

$ cd pipresents; python pp_editor.py

This brings up a graphical editor. Then follow these menus:

Profile|New from template|Mediashow

Choose a short easy-to-type name such as drjmedia.

Click on media.json and then you can start adding images and movies. These are known as “tracks.”

Remove the example track.

Add your own images and movies.

Do a Profile|Validate

There is no Save! Just kill it.

And to run it full screen from your home directory:

$ python pipresents/pipresents -ftop -p drjmedia

Autostarting your mediashow
The instructions provided in the manual.pdf worked on my older Pi, but not on the B+ model Pis. So to repeat it here, modifying it so that it is more correct (the author doesn’t seem comfortable with Linux). Manual.pdf has:

$ mkdir -p ~/.config/lxsession/LXDE
$ cd !$; echo "python pipresents/pipresents.py -ftop -pdrjmedia" > autostart
$ chmod +x autostart

And as I say this worked on my model B Pi, but not my B+. The following discussion about autostarting programs is specific to operating systems which use the LXDE desktop environment such as Raspbian. On the B+ this fairly different approach worked to get the media show automatically starting upon boot:

$ cd /etc/xdg/autostart

Create a file pipresents.desktop with these lines:

[Desktop Entry]
Type=Application
Name=pipresents
Exec=python pipresents/pipresents.py -ftop -pdrjmedia
Terminal=true

But I recommend this approach which also works:

$ mkdir ~/.config/autostart

Place a pipresents.desktop file in this directory with the contents shown above.

More sophisticated approach for better black box operations
We find it convenient to run pp_editor in a virtual display created by vnc. Then we still don’t need to attach keyboard or mouse to the Pi. But the problem is that pipresents will also launch in the vnc session and really slow things down. This is a solution I worked out to have only one instance of pipresents run, even if others X sessions are launched on other displays. Note that this is a general solution and applies to any autostarted program.

The main idea is to test in a simple shell script if our display is the console (:0.0) or not.

I should interject I haven’t actually tested this but I think it’s going to work! Update: Yes, it did work!

Put startpipresents.sh in /home/pi with these contents:

#!/bin/bash
# DISPLAY environment variable is :0.0 for the console display
echo $DISPLAY|grep :0 > /dev/null 2>&1
if [ "$?" == "0" ]; then
#  matched. start pipresents in this xsession, but not any other one
  python pipresents/pipresents.py -ftop -pdrjmedia
fi

Then pipresents.desktop becomes this:

[Desktop Entry]
Type=Application
Name=pipresents
Exec=/home/pi/startpipresents.sh
Terminal=true

To install the vnc server:

$ sudo apt-get install tightvncserver

And to auto-launch it make a vnc.desktop file in ~/.config/autostart like this:

[Desktop Entry]
Type=Application
Name=vncserver
Exec=/home/pi/startvncserver.sh
Terminal=false

and put this in the file /home/pi/startvncserver.sh:

#!/bin/bash
# DISPLAY environment variable is :0.0 for the console display
echo $DISPLAY|grep :0 > /dev/null 2>&1
if [ "$?" == "0" ]; then
#  matched. start vncserver in this xsession, but not any other one
  vncserver
fi

You need to launch vncserver by hand once to establish the password.

And we may as well pre-launch the pp_editor because we’re likely to need that. So make a file in the home directory called startppeditor.sh with these contents:

#!/bin/bash
# DISPLAY environment variable is :1.0 for the vnc display
echo $DISPLAY|grep :1 > /dev/null 2>&1
if [ "$?" == "0" ]; then
#  matched. start ppeditor in this xsession, but not any other one
  python pipresents/pp_editor.py
fi

and in ~/.config/autostart a file called ppeditor.desktop with these contents:

[Desktop Entry]
Type=Application
Name=ppeditor
Exec=/home/pi/startppeditor.sh
Terminal=true

Similarly we can pre-launch an lxterminal because we’ll probably need one of those. Here’s an example startlxterminal.sh:

#!/bin/bash
# DISPLAY environment variable is :1.0 for the vnc display
echo $DISPLAY|grep :1 > /dev/null 2>&1
if [ "$?" == "0" ]; then
#  matched. start a large lxterminal in this xsession, but not any other one
  lxterminal --geometry=100x40
fi

and the autostart file:

[Desktop Entry]
Type=Application
Name=lxterminal
Exec=/home/pi/startlxterminal.sh
Terminal=true

A note about Powerpoint slides
With a Macbook we were able to read in a Powerpoint slideshow and export it to JPEG images, one image per slide. That was pretty convenient. We have done the same directly from Microsoft Powerpoint – it’s a save option.

A note about Mpeg4 videos
Some videos overwhelm these older Pis that we use. Maybe on the Pi 3 they’d be OK? A creative student would hand us his 2 minute movie in mpeg4 format. The Pi would never be able to display it. We learned you can reduce the resolution to get the Pi to display it. A student was doing this on his Macbook, but when he left i had to figure out a way.

The original mpeg4 video had resolution of 1920 x 1080. I wanted to have horizontal resolution of no more than 1232, but maybe even smaller, while preserving the aspect ratio (widescreen format).

I used good ole’ Microsoft Movie Maker. I don’t think it’s available any longer except from dodgy sites, but in the days of Windows 7 you could get it for free through Windows Live Update. Then, if you upgraded that Windows 7 PC to Windows 10, it allowed you to keep Movie Maker. That’s the only way I know of. Not that it’s a good program. It’s not. Very basic. But it does permit resizing a video stream to custom resolution, so I have to give it that. I tried various resolutions nd played them back. i finally settled on the smallest I tried: 800×450. In fact I couldn’t really tell the difference in video quality between all the samples. And of corse 800×450 made for the smallest file. So we took that one. Fortunately, pipresents blew it up to occupy the full screen width (1232 pixels) while preserving the aspect ratio. So it looks great and no further action was needed.

The sound of silence
You want the video sound to come out the stereo mini-jack because you’re not using an HDMI monitor? PiPresents tries to send audio out through HDMI by default so you won’t hear the sounds if you have a VGA monitor. But you can change that. If you want to do this in raw omxplayer the switch which sends the sound out through the mini-jack is:

omxplayer -o local

In pipresents this option is available in the pp_editor. It’s a property of the profile. So you edit the profile, look for omx-audio, and change its value in the drop-down box from hdmi to local. That’s it!

A word about DHCP
We use a PC to connect to the four Pis. They are connected to a hub and there is an Ethernet cable connected to the hub and ready to be connected to a PC with an Ethernet port. The Pis all have private IP addresses: 10.31.42.1, 10.31.42.2, 10.31.42.3 and 10.31.42.4. For convenience, we set up a DHCP server on Pi 1 so that when the PC connects, it gets assigned an IP address on that subnet. DHCP is a service that dynamically assigns IP addresses. Turns out this is dead easy. You simply install dnsmasq (sudo apt-get install dnsmasq) and make sure it is enabled. That’s it! More sophisticated setups require modification of the file /etc/dnsmasq.conf, but for our simple use case that is not even needed – it just picks reasonable values and assigns an appropriate IP to the laptop that allows it to communicate to any of the four Pis.

References and related
I worked on this project with a student. Building a Four Monitor Media Show using Raspberry Pis
Pipresents has its own wordpress site.

LXDE has its own official site.
Read about a first look at the custom-built 7″ Raspberry Pi touch display in this blog post.

An alternative slideshow program to pipresents is to leverage qiv. I put something together and demo it in this post, but with a twist: I pull all the photos from my own Google Drive, where I store 40,000+ pictures!

Categories
DNS

“FBI’s” DNS Severs – Trying to Clear Some of the Hysteria

Intro
This Fox News article about infected computers was brought to my attention:
Hundreds of thousands may lose Internet in July

Hey, their URLs look like my URLs. Wonder if they’re using WordPress.

But I digress. I was asked if this is a hoax. I really had to puzzle over it for awhile. It smells like a hoax. I didn’t find any independent confirmation on the isc.org web site, where I get my BIND source files from. I didn’t see a blog post from Paul Vixie mentioning this incident.

And the comments. Oh my word the comments. Every conspiracy theorist is eating this up, gorging on it. The misinformation is appalling. There is actually no single comment as of this writing (100+ comments so far) that lends any technical insight into the saga.

Let’s do a reset and start from a reasonable person basis, not political ideology.

To recount, apparently hundreds of thousands of computers got hacked in a novel way. They had their DNS servers replaced with DNS servers owned by hackers. in Windows you can see your DNS servers with

> ipconfig /all

in a CMD window.

Look for the line that reads

DNS Servers…

These DNS servers could redirect users to web sites that encouraged users to fill out surveys which generated profit for the hackers.

It’s a lot easier to control a few servers than it is to fix hundreds of thousands of desktops. So the FBI got permission through the courts to get control of the IP addresses of the DNS servers involved and decided to run clean DNS servers. This would keep the infected users working, and they would no longer be prompted to fill out surveys. In fact they would probably feel that everything was great again. But this solution costs money to maintain. Is the FBI running these DNS servers? I highly, highly doubt it. I’ll bet they worked with ISC (isc.org) who are the real subject matter experts and quietly outsourced that delicate task to them.

So in July, apparently, (I can’t find independent confirmation of the date) they are going to pull the plug on their FBI DNS servers.

On that day some 80,000 users in the US alone will not be able to browse Internet sites as a result of this action, and hundreds of thousands outside of the US.

If the FBI works with some DNS experts – and Paul Vixie is the best out there and they are apparently already working with him – they could be helpful and redirect all DNS requests to a web site that explains the problem and suggests methods for fixing it. It’s not clear at this point whether or not they will do this.

That’s it. No conspiracy. The FBI was trying to do the right thing – ease the users off the troubled DNS services to somewhat minimize service disruption. I would do the same if I were working for the FBI.

Unfortunately, feeding fodder to the the conspiracists is the fact that the mentioned web site, dcwg.org, is not currently available. The provenance of that web site is also hard to scrutinize as it’s registered to an individual, which looks fishy. But upon digging deeper I have to say that probably the site is just overwhelmed right now. It was first registered in November – around the time this hack came to light. It stands for DNS Changer Working Group.

Comparitech provides more technical details in this very well-written article: DNS changer malware.

Another link on their site that discusses this topic: check-to-see-if-your-computer-is-using-rogue-DNS

Specific DNS Servers
I want to be a good Netizen and not scan all the address ranges mentioned in the FBI document. So I took an educated guess as to where the DNS servers might actually reside. I found three right off the bat:

64.28.176.1
213.109.64.1
77.67.83.1

Knowing actual IPs of actual DNS servers makes this whole thing a lot more real from a technical point-of-view. Because they are indeed unusual in their behaviour. They are fully resolving DNS servers, which is a rarity on the Internet but would be called for by the problem at hand. Traceroute to them all shows the same path, which appears to be somewhere in NYC. A DNS query takes about 17 msec from Amazon’s northeast data center which is in Virginia. So the similarity of the path seems to suggest that they got hold of the routing for these subnets and are directing them to the same set of clean DNS servers.

Let’s see what else we can figure out.

Look up 64.28.176.1 on arin.net Whois. More confirmation that this is real and subject to a court order. In the comments section it says:

In accordance with a Court Order in connection with a criminal investigation, this registration record has been locked and during the period from November 8, 2011 through March 22, 2012, any changes to this registration record are subject to that Court Order.

I thought we could gain even more insight looking up 213.109.64.1 which is normally address range outside of North America, but I can’t figure out too much about it. You can look it up in the RIPE database (ripe.net). You will in fact see it is registered to Prolite Ltd in Russia. No mention of a court order. So we can speculate that unlike arin.net, RIPE did not bother to update their registration record after the FBI got control. So Prolite Ltd may either have been an active player in the hack, or merely had some of their servers hacked and used for the DNSchanger DNS server service.

Of course we don’t know what the original route looked like, but I bet it didn’t end in new York City, although that can’t be ruled out. But now it does. I wonder how the FBI got control of that subnet and if it involved international cooperation.

7/9 update
The news reports re-piqued my interest in this story. I doubled back and re-checked those three public DNS servers I had identified above. 64.28.176.1, etc. Sure enough, they no longer respond to DNS queries! The query comes back like this:

$ dig ns com @77.67.83.1

; <<>> DiG 9.7.3-P3-RedHat-9.7.3-8.P3.el6_2.2 <<>> ns com @77.67.83.1
;; global options: +cmd
;; connection timed out; no servers could be reached

Conclusion
As a DNS and Internet expert I have some greater insight into this particular news item than the average commentator. Interested in DNS? Here’s another article I wrote about DNS: Google’s DNS Servers Rock!

References and related
Here’s a much more thorough write-up of the DNS Changer situation: http://comparitech.net/dnschangerprotection