Adguard DNS, or how to reduce ads without apps/extensions

Looking at the options for blocking ads, people usually first look at browser extensions. Google's plan is to disable adblock extensions in 2024. The alternative is usually an app (on phones) or a "VPN" that does filtering for you. All these methods are quite heavyweight, and require installing software on your phone or PC. What is less known, is that you can you DNS-over-TLS or DNS-over-HTTPS for ad blocking.

What is DNS-over-TLS and DNS-over-HTTPS

Since Android 9, Google has provided a setting calledPrivate DNS. Traditional DNS is unencrypted UDP so anyone can monitor your requests and/or return false records. With private DNS, DNS-over-TLS or DNS-over-HTTPS is used to guarantee the DNS request is sent to the server you configured. Which Google hopes is of course Google's own public servers. If you do so, your ISP and hotspot providers no longer can monitor, monetize and enshittify your DNS requests - only Google can do so.

Subverting private DNS for ad blocking

This is where AdGuard DNS comes useful. By setting the AdGuard DNS server as your "private DNS" server following the instructions,you can start blocking right away. Note, on PC you can also configure the Adguard DNS server on the Browser settings (Firefox -> Enable secure DNS and Chrome -> Use Secure DNS) instead of configuring a system-wide DNS server. Blocking via DNS, of course, limits effectiveness to ads distributed from 3rd party servers.

Other uses for AdGuard DNS

If you register for Adguard DNS, you get your "own", customizable DNS server address to point to. You can, for example, create your own /etc/hosts style records that are now available to all you devices you have connected to the Adguard DNS server - whether your a are home or not. Of course, you choose to use the personal DNS server, your DNS query privacy is in the hands of AdGuard.

Going further

What else is ruining the web than Ads? Well commercial social media. An article ("Ei näin! – Algoritmiähky") from the latest Finnish Magazine SKROLLI (mainos: jos luet suomeksi, Tilaa skrolli!) hit a chord for me. The algorithms of social media sites are designed not to serve you, but to addict you. For example, If you stop to watch a hateful meme image, the algorithm will record "The user spent time watching this, show more of the same!". It doesn't help block or mute - yeah that spefic hate engager will be blocked, but all the dozens similar hate pages will still be shown to you. Worse, the social media sites are being overrun by AI-generated crap. Unfortunately the addictive nature of the algorithms works. You reload in vain, hoping this time the algorithmic god will show something your friends share. How do you cure addiction? By blocking yourself out:

Epilogue

I didn't block myself out of Fediverse - yet. It's not engineered to be addictive, which is also probably why it isn't as popular as the commercial alternatives...

Dropping gas taxes is pointless

The current high prices of gasoline have made many people to demand gas tax cuts. Some governments have even responded to the call, and cut gas taxes. I do understand some people are hit hard by rising gas prices. But in Finnish we have a saying "Pakkasella pissa housuissa lämmittää vain hetken". Roughly Translated "In winter, peeing into your pants will only keep you warm for a moment".

See, the reason for the current high gas prices is simple: Demand > Supply. As long as there more demand than there is supply, the prices keep rising until demand and supply matches. If you want the gas prices to drop, you have to either increase supply or reduce demand - usually you want both. Reducing gas tax does neither. In fact, reducing gas tax INCREASES DEMAND, as after tax cut people can afford to drive around more...

So while cutting taxes reduce prices for a short period of time, the end result is just more pressure to rise gas prices. Cutting gas taxes is a great way to get you re-elected, but if you really want to help the people struggling with high gas prices, you should do something else.

Reality is of course more complex - with everyone expecting a recession, the oil prices are already falling regardless of any tax changes. 

This is the year not to fly

If you have to choose one year when you won't fly, this year, 2020, is the one to choose. Why? Because CORSIA.

What the heck is CORSIA?

CORSIA is not a novel virus, but "Carbon Offsetting and Reduction Scheme for International Aviation". In a nutshell, the aviation industry says they will freeze their co2 emissions from growing. Actually, aviation emissions are still going to grow. The airlines will just pay someone else to reduce emissions with the same amount aviation emissions rise - the "Offsetting" word in CORSIA. If that sounds like greenwashing, well it pretty much is. But that was expected. Getting every country and airline abroad CORSIA would not have been possible if the scheme would actually bite. So it's pretty much a joke.

What does it have to do with *this* Year?

The first phase of CORSIA will start next year, so the emissions are frozen to year 2020 levels. Due to certain recent events, lots of flights have already been cancelled - which means the reference year aviation emissions are already a lot less than the aviation industry was expecting. By avoiding flying this year, the aviation emissions are going to be frozen at an even lower level. This will increase cost of co2 offsetting for airlines, and the joke is going to be on them.

So consider skipping business travel and taking your holiday trip this year with something else than a plane. Wouldn't recommend a cruise ship, tho...

On the #uploadfilter problem

The copyright holders in europe are pushing hard mandate upload filters for internet. We have been here before - when they outlawed circumventing DRM. Both have roots in the same problem. The copyright holders look at computers and see bad things happening to their revenue. They come to IT companies and say "FIX IT". It industry comes back and says.. "We cant.. making data impossible to copy is like trying to make water not wet!". But we fail at convincing copyright holders in how perfect DRM or upload filter is not possible. Then copyright holders go to law makers and ask them in turn to fix it.

We need to turn tables around. If they want something impossible, it should be upto them to implement it.

It is simply unfair to require each online provider to implement an AI to detect copyright infringement, manage a database of copyrighted content and pay for the costs running it all.. ..And getting slapped with a lawsuit anyways, since copyrighted content is still slipping through.

The burden of implementing #uploadfilter should be on the copyright holder organizations. Implement as a SaaS. Youtube other web platforms call your API and pay $0.01 each time a pirate content is detected. On the other side, to ensure correctness of the filter, copyright holders have to pay any lost revenue, court costs and so on for each false positive.

Filtering uploads is still problematic. But it's now the copyright holders problem. Instead people blaming web companies for poor filters, it's the copyright holders now who have to answer to the public why their filters are rejecting content that doesn't belong to them.

Linus Torvalds is wrong - PC no longer defines a platform

Hey, I can do these clickbait headlines too! Recently it has gotten media's attention that Linus is dismissive of ARM servers. The argument is roughly "Developers use X86 PCs, cross-platform development is painful, and therefor devs will use X86 servers, unless they get ARM PCs to play with".

This ignores the reality where majority of developers do cross-platform development every day. They develop on Mac and Windows PC's and deploy on Linux servers or mobile phones. The two biggest Linux success stories, cloud and Android, are built on cross-platform development. Yes, cross-platform development sucks. But it's just one of the many things that sucks in software development.

More importantly, the ship of "local dev enviroment" has long since sailed. Using Linus's other great innovation, git, developers push their code to a Microsoft server, which triggers a Rube Goldberg machine of software build, container assembly, unit tests, deployment to test environment and so on - all in cloud servers.

Yes, the ability to easily by a cheap whitebox PC from CompUSA was the important factor in making X86 dominate server space. But people get cheap servers from cloud now, and even that is getting out of fashion. Services like AWS lambda abstract the whole server away, and the instruction set becomes irrelevant. Which CPU and architecture will be used to run these "serverless" services is not going to depend on developers having Arm Linux Desktop PC's.

Of course there are still plenty of people like me who use Linux Desktop and run things locally. But in the big picture things are just going one way. The way where it gets easier to test things in your git-based CI loop rather than in local development setup.

But like Linus, I still do want to see an powerful PC-like Arm NUC or Laptop. One that could run mainline Linux kernel and offer a PC-like desktop experience. Not because ARM depends on it to succeed in server space (what it needs is out of scope for this blogpost) - but because PC's are useful in their own.

Making sense of /proc/cpuinfo on ARM

Ever stared at output of /proc/cpuinfo and wondered what the CPU is?

...
processor       : 7
BogoMIPS        : 2.40
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 3

Or maybe like:

$ cat /proc/cpuinfo
processor       : 0
model name      : ARMv7 Processor rev 2 (v7l)
BogoMIPS        : 50.00
Features        : half thumb fastmult vfp edsp thumbee vfpv3 tls idiva idivt vfpd32 lpae
CPU implementer : 0x56
CPU architecture: 7
CPU variant     : 0x2
CPU part        : 0x584
CPU revision    : 2
...

The bits "CPU implementer" and "CPU part" could be mapped to human understandable strings. But the Kernel developers are heavily against the idea. Therefor, to the next idea: Parse in userspace. Turns out, there is a common tool almost everyone has installed does similar stuff. lscpu(1) from util-linux. So I proposed a patch to do ID mapping on arm/arm64 to util-linux, and it was accepted! So using lscpu from util-linux 2.32 (hopefully to be released soon) the above two systems look like:

Architecture:        aarch64
Byte Order:          Little Endian
CPU(s):              8
On-line CPU(s) list: 0-7
Thread(s) per core:  1
Core(s) per socket:  4
Socket(s):           2
NUMA node(s):        1
Vendor ID:           ARM
Model:               3
Model name:          Cortex-A53
Stepping:            r0p3
CPU max MHz:         1200.0000
CPU min MHz:         208.0000
BogoMIPS:            2.40
L1d cache:           unknown size
L1i cache:           unknown size
L2 cache:            unknown size
NUMA node0 CPU(s):   0-7
Flags:               fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid

And

$ lscpu
Architecture:        armv7l
Byte Order:          Little Endian
CPU(s):              4
On-line CPU(s) list: 0-3
Thread(s) per core:  1
Core(s) per socket:  4
Socket(s):           1
Vendor ID:           Marvell
Model:               2
Model name:          PJ4B-MP
Stepping:            0x2
CPU max MHz:         1333.0000
CPU min MHz:         666.5000
BogoMIPS:            50.00
Flags:               half thumb fastmult vfp edsp thumbee vfpv3 tls idiva idivt vfpd32 lpae

As we can see, lscpu is quite versatile and can show more information than just what is available in cpuinfo.

Cross-compiling with debian stretch

Debian stretch comes with cross-compiler packages for selected architectures:

 $ apt-cache search cross-build-essential
crossbuild-essential-arm64 - Informational list of cross-build-essential packages for
crossbuild-essential-armel - ...
crossbuild-essential-armhf - ...
crossbuild-essential-mipsel - ...
crossbuild-essential-powerpc - ...
crossbuild-essential-ppc64el - ...
⏎                                                                                       

Lets have a quick exact steps guide. But first - while you can use do all this in your desktop PC rootfs, it is more wise to contain yourself. Fortunately, Debian comes with a container tool out of box:

sudo debootstrap stretch /var/lib/container/stretch http://deb.debian.org/debian
echo "strech_cross" | sudo tee /var/lib/container/stretch/etc/debian_chroot
sudo systemd-nspawn -D /var/lib/container/stretch

Then we set up cross-building enviroment for arm64 inside the container:

# Tell dpkg we can install arm64
dpkg --add-architecture arm64
# Add src line to make "apt-get source" work
echo "deb-src http://deb.debian.org/debian stretch main" >> /etc/apt/sources.list
apt-get update
# Install cross-compiler and other essential build tools
apt install --no-install-recommends build-essential crossbuild-essential-arm64

Now we have a nice build enviroment, lets choose something more complicated than the usual kernel/BusyBox to cross-build, qemu:

# Get qemu sources from debian
apt-get source qemu
cd qemu-*
# New in stretch: build-dep works in unpacked source tree 
apt-get build-dep -a arm64 .
# Cross-build Qemu for arm64
dpkg-buildpackage -aarm64 -j6 -b

Now that works perfectly for Qemu. For other packages, challenges may appear. For example you may have to se "nocheck" flag to skip build-time unit tests. Or some of the build-dependencies may not be multiarch-enabled. So work continues :)