Inconsistent CJDNS address handling in Local addresses and AddLocal logs #33471

When running:

./build/bin/bitcoind -daemon -server=1 -onion=127.0.0.1:9050 -externalip=<hostname_addr> -listen -cjdnsreachable

only two Tor addresses appear under Local addresses and no CJDNS addresses in bitcoin-cli -netinfo 4. The log also shows two AddLocal(...) entries for the onion address, but none for the CJDNS address. However, adding a CJDNS peer via addnode ... add works as expected.

In contrast, running:

./build/bin/bitcoind -daemon -listen -cjdnsreachable

shows one Tor address and one CJDNS address in Local addresses. The log also includes one AddLocal(...) for the onion address and one for the CJDNS address, and peer addition works normally.

This seems inconsistent: in the first case, shouldn’t the CJDNS address also appear in Local addresses and be logged with AddLocal(<cjdns_addr>)?

@willcl-ark please assign me this issue i can fix this bug

@big14way you don't need to be assigned an issue to work on it in this project. Opening a pull request (please read CONTRIBUTING.md frist) and linking it to this issue in the PR description is all that's needed.

@willcl-ark thank you for clarifyingi will look through the CONTRIBUTING.md frist i appreciate it

جحخ

I tested this locally and, unless I am missing something, I do not think that there is a bug here. Adding -externalip disables -discover as it should and as documented:

https://github.com/bitcoin/bitcoin/blob/341360964a6fef725825639edc507c275f8ad0b2/src/init.cpp#L573

That means bitcoin-cli getnetworkinfo |jq .localaddresses will not display any CJDNS or IPv4 or IPv6 address that is auto discovered by looking up at the local interfaces. Without -externalip=:

[
  {
    "address": "1.2.3.4",
    "port": 8333,
    "score": 1
  },
  {
    "address": "fc00:1::1",
    "port": 8333,
    "score": 1
  }
]

(I have 1.2.3.4 and fc00:1::1 configured on local interfaces)

With -externalip=5.6.7.8

[
  {
    "address": "5.6.7.8",
    "port": 8333,
    "score": 4
  }
]

... only two Tor addresses appear under Local addresses ...

Why two? I would expect one Tor address.

A proper configuration is, if -externalip= is to be used, then to use it for all listening addresses explicitly instead of using it for some and relying on others to be auto discovered.

Thanks for looking into this.

I understand that -externalip currently disables -discover, so the current behavior is consistent with that rule.

However, I would not expect specifying an IPv4/IPv6 address via -externalip= to also suppress CJDNS address discovery/advertisement, since CJDNS is a separate network and a clearnet -externalip is not useful to CJDNS peers.

I couldn't find this interaction documented explicitly.

If this behavior should be kept, maybe we should at least log a clearer message when -externalip suppresses CJDNS discovery too.

However, I would not expect specifying an IPv4/IPv6 address via -externalip= to also suppress CJDNS address discovery/advertisement ...

Well, that is the same as if -externalip=some.ip.v.4 is used - that would suppress IPv6 address discovery.