Merge #19728: Increase the ip address relay branching factor for unreachable networks

86d4cf42d97abf4c436d1eabf29e2ed150f69c1e Increase the ip address relay branching factor for unreachable networks (Pieter Wuille)

Pull request description:

  Onion addresses propagate very badly among the IPv4/IPv6 network, resulting
  in difficulty for those to find each other.

  The branching factor 1 is probably so low that propagations die out before
  they reach another onion peer. Increase it to 1.5 on average.

ACKs for top commit:
  practicalswift:
    ACK 86d4cf42d97abf4c436d1eabf29e2ed150f69c1e -- patch looks correct
  naumenkogs:
    ACK 86d4cf4
  jonatack:
    ACK 86d4cf42d97abf4c436d1eabf29e2ed150f69c1e. Code review, built and running with some sanity check logging. `RelayAddress()` is called by `ProcessMessage() ADDR` msg handling, from within the loop while processing each new address to relay it to a limited number of other nodes. According to git blame, the line setting `nRelayNodes` hasn't been touched since 2016 in e736772c56a *Move network-msg-processing code out of main to its own file*, which moved the line but otherwise did not change it. Running a mixed clearnet/onion node with this patch and the logging below, I'm only seeing values of `fReachable 1, nRelayNodes 2`. IIUC, I need to use the settings in `init.cpp` that call `SetReachable(*, false)`. *Edit:* with `onlynet=onion` am now seeing entries of `fReachable 0` with `nRelayNodes` values of 1 and 2.
  vasild:
    ACK 86d4cf42d

Tree-SHA512: 22391e16d60bcfdec9a9336728da39d68a24a183b3d1b0e8fbc038d265ca6ddf71d16db018f3678745fd9f3e9281049e42197fa0a29124833c50a9170ed6f793

0 files changed, 0 insertions, 0 deletions