# Ping your part!

- Published on 9th February, 2023 -

Propaganda poster from the Furry Tech room from when the canvas was attacked

Tags: tech,fun

On February 6th 2023, Cameron Steel introduced the world to the IPv6 Canvas via a blog post of his.
The idea is simple: a 256x256 pixel grid where you have to ping an IPv6 to change a pixel.
Basically, each pixel has its own address, referencing X and Y position but also RGB values, making it possible to print a variety of images all accross it.

Early in the launch, there was already this little guy:

I originally discovered the project in the morning of February 7th, via the Ungleich IPv6 Matrix room.
I immediately started tinkering with Python to try and print an image.

At first, I started generating the addresses.
Doing so is really easy, just take the base address and fill out the gaps with values:

``````base_address = "2400:8902:e001:233"
pixels = []

def make_image_and_start(ox, oy, image_path, to_file=False, filename="image.txt"):
image = Image.open(image_path).convert("RGBA")
max_w, max_h = image.size

curr_w, curr_h = 0, 0

start_w = int(ox)
start_h = int(oy)

max_w -= 1
max_h -= 1

# Now, let's convert the image
while True:
coordinates = x, y = curr_w, curr_h
r, g, b, a = image.getpixel(coordinates)

print(f"Converting: {x},{y} -> {r}:{g}:{b}/{a}", end="\r")

# Check for alpha (transparency support)
if a > 0:
pixels.append(make_address(curr_w + start_w, curr_h + start_h, r, g, b))

# Basic printer that goes left-> right and starts again
if curr_h == max_h:
curr_h = 0
curr_w += 1
else:
curr_h += 1

if curr_w == max_w and curr_h == max_h:
curr_h = start_h
curr_w = start_w
break
``````

Then, my original thought was to start using the `ping` command but it ended up being slow, taking half an hour to draw even half of the original image.
That’s when I had the idea of outputting everything in a text file and then using `fastping -f` on top of it which was working better!

Still, there was lots of room for improvement and it showed when the whole canvas was replaced with a moving rickroll (nicely done btw).
Few hours later, a friend started testing `oping` which turns out to be faster than `fastping`.
That method worked great until I finally started using raw sockets in my own script:

``````sock = socket(socket.AF_INET6, socket.SOCK_RAW, socket.IPPROTO_ICMPV6)

print(f"Rendering current: {dest_addr}", end="\r")

try:
# Raw sockets, who cares, it's fast
except:
# We don't care about failing
# The pixel is usually re-written in next pass
pass
``````

At first, the program would crash, citing a buffer space error.
Just ignoring the error makes it work and the loss is negligible since multiple passes are done quickly.

Victory, I could now draw images super fast which protected my artwork from attacks after.
You can see the source of the writer on SourceHut.

All in all, this was a great experiment and I want to thank Cameron for creating it in the first place.
I am currently trying to implement my own canvas which would be a tad bigger.

Also, thanks to everybody that participated in good faith, was lots of fun!

That’s it for this post and I’ll see you in the next one!

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Canvas screenshot and amogus GIF provided by Cameron Steel.