Support DNS hostnames in node announcements

[remyers]

Add support for DNS host names

Notable changes:

• you can now specify a DNS host name as one of your server.public-ips addresses (see PR #911). Note: you can not specify more than one DNS host name.
• An IPv4, IPv6 or DNS hostname with port of 0 is invalid as per Bolt #7.
• DNS host names will not be resolved until Client attempts to connect to a peer.
• will not rebroadcast a NodeAnnouncement that contains more than one DNS host name
• the codec does not implement punycode parsing; we should create an issue if we want to support non-ASCII character sets for DNS host names
• DNS host name addresses must be resolved to determine if they are IPv4 or IPv6 when deciding whether or not to use a proxy.

To do:

• interop testing with c-lightning PR# 4829
• interop testing with LND Issue# 6337
• interop testing with LDK PR# 1329

See also PR #2202 - Use NodeAddress everywhere
and PR #2296 - drop Tor v2 support

[remyers]

Simple interop testing with CLN v0.10.2-252-gc0e3155 configured with:
./configure --enable-experimental-features --enable-developer

Overview of setup:

Alice [Eclair] @ dnstest1.co.fr <---> Bob [CLN] @ dnstest2.co.fr <---> Carol [Eclair] @ dnstest3.co.fr

Added to local /etc/hosts:

127.0.0.1       dnstest1.co.fr
127.0.1.1       dnstest2.co.fr
127.0.2.1       dnstest3.co.fr

Created a script dns_gossip.sh to test that DNS hostnames are gossiped between Eclair and CLN.

dns_gossip.sh

Launch bicoind with ./scripts/start-bitcoin.sh, run nodes: alice-eclair & bob-clightning & carol-eclair & and then run the test script ./scripts/dns_gossip.sh.

Example result:

$ ./scripts/dns_gossip.sh 
Alice is 02ca09b2d0fdab441e7e41019e021db360838478484ff191feaf0e49cc13e7a9ba
Bob is 02a821bf4d075dcb88104ab2784ee87ece8979c1e2492c50cac5cdbcaedf686cfc
Carol is 0384f3fca93a670a854f1b9732965b22920c02745f3d91e8084793bf0c7b69f5b5
Adding some Bitcoin to wallets...
Generating a few blocks to confirm wallet balances...
Opening channels between Alice and Bob...
Opening channels between Bob and Carol...
Generating a few blocks to confirm channels...
Creating invoices...
Awaiting gossip sync...
Gossip sync took 14 seconds
Paying invoices...
1. BOB -> CAROL [10,000]
complete
2. ALICE -> BOB [10,000]
payment-sent
3. CAROl -> BOB -> ALICE [5,000]
payment-sent
4. ALICE -> BOB -> CAROL [20,000]
payment-sent
5. BOB -> ALICE [10,000]
complete
6. CAROL -> BOB [5,000]
payment-sent
All invoices paid
"echo All invoices paid" command filed with exit code 0.

To re-run dns_gossip.sh you first must kill the three nodes, reset their databases with ./scripts/reset_all_nodes.sh and then start the nodes again.

[remyers]

Note: the .invalid top level domain will never resolve.

[t-bast]

The logic looks good to me, I only have small cosmetic/architectural comments, good job!
This does need a rebase though.

[remyers]

As per Roasbeef at today's meeting, LND 0.15 will propagate DNS hostnames, so nodes running a version from about a month ago should not disappear if they add dns host names to their node announcements.

[t-bast]

LGTM, a couple of nits and a question for @pm47 about the sun.net dependency.
This needs a rebase, which should be trivial.

[codecov-commenter]

Codecov Report

Merging #2234 (c2df6d2) into master (33e6fac) will decrease coverage by 0.06%.
The diff coverage is 96.15%.

@@            Coverage Diff             @@
##           master    #2234      +/-   ##
==========================================
- Coverage   84.95%   84.89%   -0.07%     
==========================================
  Files         198      198              
  Lines       15255    15277      +22     
  Branches      633      640       +7     
==========================================
+ Hits        12960    12969       +9     
- Misses       2295     2308      +13     

Impacted Files	Coverage Δ
...re/src/main/scala/fr/acinq/eclair/NodeParams.scala	93.11% <87.50%> (-0.17%)	⬇️
...ore/src/main/scala/fr/acinq/eclair/io/Client.scala	56.60% <100.00%> (+0.83%)	⬆️
...in/scala/fr/acinq/eclair/io/ReconnectionTask.scala	98.07% <100.00%> (ø)
...n/scala/fr/acinq/eclair/router/Announcements.scala	100.00% <100.00%> (ø)
...main/scala/fr/acinq/eclair/router/Validation.scala	94.11% <100.00%> (-1.24%)	⬇️
...n/scala/fr/acinq/eclair/tor/Socks5Connection.scala	9.37% <100.00%> (+0.71%)	⬆️
...a/fr/acinq/eclair/wire/protocol/CommonCodecs.scala	97.05% <100.00%> (+0.04%)	⬆️
...q/eclair/wire/protocol/LightningMessageTypes.scala	94.64% <100.00%> (+0.52%)	⬆️
...q/eclair/channel/publish/ReplaceableTxFunder.scala	86.91% <0.00%> (-3.67%)	⬇️
...cala/fr/acinq/eclair/payment/relay/NodeRelay.scala	95.93% <0.00%> (-1.63%)	⬇️
... and 5 more

[t-bast]

LGTM, good job 💯