On 22 Nov (17:36:33), David Goulet wrote:
Hi everyone!
We are soon at the stage of implementing the service part of proposal 224 (next gen. hidden service.). Parent ticket is #20657 but I'll be discussing here ticket #18054.
In a nutshell, we need to figure out the interface for the torrc file[1]. We currently have some options to configure an hidden service and the question is now how do we proceed on using those for next version?
[snip]
(Please read original email for some initial context.)
So over the last week, we've mashed up all the things that were said in this thread, me and asn discussed it with some arma also on the side!
I think the following is the best of all the non ideal solutions we can come up with. Below is a superb ascii timeline of what we plan to do in terms of transition from v2 to v3:
Our dystopian reality of now. (https://youtu.be/NrmMk1Myrxc it's not a Black Mirror SO3 trailer) v | ~Aug '17 ~Dec '17 Unknown date |-----------------|-----------------|----------------|----------> | ^ ^ ^ v3 Network/Code | tor stable release Maturity | with v3 support No more v2 (0.3.1)
Ok, might not be my best ascii art work but I hope it will do. In short:
- With 0.3.1 (scheduled for August 2017, subject to change), we'll have a tor with v3 support BUT v2 will still be the default value for *new* HS. (HiddenServiceVersion option)
- For a period of ~4 months we estimate, we'll hope that enough of the network has upgraded to support v3 (relay and HSDir support are in 030) and that the code as some sort of maturity that we are confident to switch and make all new HS be v3. This is the "v3 Network/Code Maturity" marker. Note that it could easily go to 2018 for this switch to happen.
- When the switch happens, there will be, most likely years, a long period of time where v2 will be deprecated and warnings given to users but still used. That "Unknown date" will be the time we will release a tor stable version _without_ v2 support at all. It's quite unknown when we'll be able to do it. Chances are that we'll rely on our HS statistics and metrics for that.
That being said, here are the conclusions based on this thread and f2f discussion considering the above "procedure":
1) When v3 is released in a tor stable version, it will NOT be the default version for new service, v2 will until maturity.
2) HiddenServiceVersion is used to control which version of the service you want. Starting from the first time v3 is supported, you'll be able to use it but without any guarantee as we'll be entering the "stabilizing period" but it should be usable.
3) ADD_ONION "BEST" will map to whatever default value HiddenServiceVersion is with the tor you have.
4) In order to avoid relying on a tor stable version release to switch the default version from 2 to 3, we'll use a consensus parameter. Meaning that once we set that param. to v3, HiddenServiceVersion default value will be that value unless explicitely defined in torrc. It will also allow us to rollback to v2 if we see a swarm of badness occuring. To be clear, service already v3 will stay v3 but the default version for creation will simply change.
5) v2 creation will be allowed pass the "v3 Network/Code Maturity" point until we phase it out for real from the code. "HiddenServiceVersion 2" will be how to do it. I've been convinced actually and mostly the main argument that made me tick is "If we don't allow it, some hackish tor or ugly recipe will be recommended on the intertubez."
6) We DO NOT want a v3 kill switch or "do not publish descriptor" parameter in the consensus. We couldn't see a useful use case apart from "Oh damn that HS v3 code is DDoSing relays" which would require a real kill switch for v3 and not just "do not publish".
A correct alternative we think is to actually have consensus params that tweak the protocol such as "Num intro point default" and "Lifetime intropoint default" and such... (there are few of those magic numbers in the code) and in case of catastrophic failure, we can tweak the knob that is causing the problem. I'll open a ticket about it if no arguable objections on this thread.
That's about it!
Please raise concerns on any point here. I personally think it's simple enough and gives us enough room to transition over time.
Thanks to everyone with your feedbacks btw, really good stuff! More prop224 email will be in an INBOX near you in the coming weeks/months as we have more points to discuss.
Cheers! David