Proposal: Add class HNS for basic blockchain metadata

[pinheadmz]

Background

We're all familiar with the IN class ("internet"):

$ dig google.com IN A
...
google.com.             300     IN      A       142.250.64.110

There are a few other lesser-known and less useful classes that are supposed to be used on local networks only, such as CH ("chaos" class):

$ dig @jay.ns.cloudflare.com version.bind CH TXT
...
version.bind.           86400   CH      TXT     "20171212"

There are a few others specified in section 3.2.4 of rfc1035: IN, CS, CH, and HS.

Currently hsd and hnsd only support IN.

Proposal

I had this idea specifically for hnsd because the program has no rpc interface or actually, no interface at all except the recursive resolver. However since it is a blockchain-processing application, it should have features that allow the user to ensure they are at least synced properly and confident that they are resolving names on the most-work chain.

I propose we add a unique class to hsd and hnsd both: HNS so a user can verify very simple blockchain status data like the current tip.

Example

$ dig @127.0.0.1 hash.tip HNS TXT
...
hash.tip             0    HNS          TXT      "0000000000000274523871d00ba2837cb6227038053af91f35f674086b4393d1"

[pinheadmz]

@chjj @mikedamm any thoughts?

[dnsguru]

@pinheadmz Here is an idea that I suggest might work...
Hesiod (Wikipedia Article) is a class that was used to shuttle TXT records around - it already exists, would likely stretch to fit the purpose

Hesiod class records would look like this

hash.tip  0   HS  TXT  "0000000000000274523871d00ba2837cb6227038053af91f35f674086b4393d1"

• They can coexist within a zone file along side IN or others, and
• They will likely cause fewer interop issues with legacy stuff out there as they might evolve, and
• An added benefit, HS = Handshake, and
• One less character

[pinheadmz]

An added benefit, HS = Handshake,

🚀

[james-stevens]

If you are querying hsd directly, this could be a workable solution, although I wouldn't just hijack somebody else's class. CLASS is a 16 bit number, so there's plenty of other values to choose from.

However, if you were trying to get other DNS servers (resolvers etc) to be able to propagate the records, I suspect you will have a lot of problems when you go outside the IN class.