change(network): Configurable maximum connections per IP

[arya2]

Motivation

This could be helpful for integration testing.

Solution

• Adds an optional maximum_connections_per_ip field to zebra-network config
• Adds the new generated configs to zebrad/tests/common/configs

Review

Anyone can review.

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[teor2345]

Thanks, looks great!

We might want to think about how to name the config files when we don't know if the next release will be 1.0.1 or 1.1.0. But that's not an issue for this PR to solve!

[codecov]

Codecov Report

Merging #7013 (fa8e14a) into main (231f5be) will decrease coverage by 0.06%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7013      +/-   ##
==========================================
- Coverage   77.44%   77.39%   -0.06%     
==========================================
  Files         310      310              
  Lines       41609    41628      +19     
==========================================
- Hits        32225    32218       -7     
- Misses       9384     9410      +26     

[teor2345]

This new config could be a new user-visible feature. So if it merges, that would make the next release a minor version (1.1.0).

This config is likely to be used in test environments. But we've also had production users say that they wanted node replication on internal networks or on the same machine, which would benefit from this config as well.

Just checking to see if anyone wants to call it a debugging feature instead?
If we want to do that, we could add "debug_" to the start of its name, and document that it is developer-focused.

(I don't mind either way, I'm just putting the question out there, so it's decided before the release.)