Send remote address in init

[t-bast]

This adds the option to report a remote IP address back to a connecting peer using the init message.
A node can decide to use that information to discover a potential update to its public IP address (NAT) and use that for a node_announcement update message containing the new address.

See lightning/bolts#917

I have successfully tested cross-compatibility with c-lightning ElementsProject/lightning#4864

[m-schmoock]

Hey @t-bast ,
clightning is tracking this in ElementsProject/lightning#4864
It can send and receive the remote_addr.
I'm currently developing the part where the daemon decides what to do when we receive a remote_addr.

We can do cross compat tests when you are ready.

[t-bast]

@m-schmoock cool, we're mostly at the same point then. I think it's worth shipping the part where we just send/receive that field whenever possible, and we can decide later how to act on it based on what we see in the wild.

This branch is ready for cross compat tests if you want. You can build it, run it locally and test it against your c-lightning branch. I have a lot of sample scripts to do cross-compat tests here if that can help.

I'll do the same on my side, I'll compile your branch and test it with mine.

[m-schmoock]

Nice, just remember to compile it with EXPERIMENTAL_FEATURES=1 as the feature will be hidden behind precompiler directives otherwise.

[t-bast]

@m-schmoock I tested this between eclair and c-lightning, we correctly parse the tlvs 👍

However your implementation currently sends back private addresses (e.g. 127.0.0.1), I think you should filter these and not include them in the tlv stream, right? It is filtered out on the eclair side, but it would be better if it wasn't sent in the first place?

[m-schmoock]

@t-bast
Yep, I still need to do that logic.

[m-schmoock]

Hi @t-bast
I have not forgotten that PR on our side, looking forward doing it this week.
We merged in experimental DNS just yet ( ElementsProject/lightning#4829 ) So if you want to pick up on that topic as well (since they are related) we can proceed on the RFCs...

[t-bast]

I have not forgotten that PR on our side, looking forward doing it this week.

No worries, there's no rush here, whenever you're ready.

We merged in experimental DNS just yet ( ElementsProject/lightning#4829 ) So if you want to pick up on that topic as well (since they are related) we can proceed on the RFCs...

To be honest I'm not that interested in the DNS one for now, that's not something our users have been asking for at all and we don't have a good use for it in the short term, so it's lower on my priority list.

[t-bast]

@m-schmoock cross-compatibility with ElementsProject/lightning#4864 is working like a charm, I tested in both directions, the reported IP address is correctly logged.

[codecov-commenter]

Codecov Report

Merging #1973 (ecb36b1) into master (27579a5) will decrease coverage by 0.07%.
The diff coverage is 88.88%.

@@            Coverage Diff             @@
##           master    #1973      +/-   ##
==========================================
- Coverage   87.62%   87.55%   -0.08%     
==========================================
  Files         166      166              
  Lines       12886    12900      +14     
  Branches      543      543              
==========================================
+ Hits        11292    11295       +3     
- Misses       1594     1605      +11     

Impacted Files	Coverage Δ
...cala/fr/acinq/eclair/crypto/TransportHandler.scala	90.21% <ø> (ø)
...q/eclair/wire/protocol/LightningMessageTypes.scala	92.50% <83.33%> (-4.28%)	⬇️
...main/scala/fr/acinq/eclair/io/PeerConnection.scala	86.74% <100.00%> (+0.91%)	⬆️
...cinq/eclair/wire/protocol/SetupAndControlTlv.scala	100.00% <100.00%> (ø)
...n/scala/fr/acinq/eclair/channel/DustExposure.scala	96.96% <0.00%> (-3.04%)	⬇️
...main/scala/fr/acinq/eclair/router/Validation.scala	90.76% <0.00%> (-2.70%)	⬇️
...clair/channel/publish/ReplaceableTxPublisher.scala	84.07% <0.00%> (-0.89%)	⬇️
...c/main/scala/fr/acinq/eclair/channel/Channel.scala	87.80% <0.00%> (-0.08%)	⬇️