* Add gocritic linter
`gocritic` provides diagnostics that check for bugs, performance, and style issues
We disable the following checks:
- commentFormatting
- captLocal
- deprecatedComment
This PR contains many `//nolint:gocritic` to disable `appendAssign`.
Add a default firewall rule to allow netbird traffic to be handled
by the access control managers.
Userspace manager behavior:
- When running on Windows, a default rule is add on Windows firewall
- For Linux, we are using one of the Kernel managers to add a single rule
- This PR doesn't handle macOS
Kernel manager behavior:
- For NFtables, if there is a filter table, an INPUT rule is added
- Iptables follows the previous flow if running on kernel mode. If running
on userspace mode, it adds a single rule for INPUT and OUTPUT chains
A new checkerFW package has been introduced to consolidate checks across
route and access control managers.
It supports a new environment variable to skip nftables and allow iptables tests
* ACL firewall manager fix/improvement
Fix issue with rule squashing, it contained issue when calculated
total amount of IPs in the Peer map (doesn't included offline peers).
That why squashing not worked.
Also this commit changes the rules apply behaviour. Instead policy:
1. Apply all rules from network map
2. Remove all previous applied rules
We do:
1. Apply only new rules
2. Remove outdated rules
Why first variant was implemented: because when you have drop policy
it is important in which order order you rules are and you need totally
clean previous state to apply the new. But in the release we didn't
include drop policy so we can do this improvement.
* Print log message about processed ACL rules
Works only with userspace implementation:
1. Configure host to solve DNS requests via a fake DSN server address in the Netbird network.
2. Add to firewall catch rule for these DNS requests.
3. Resolve these DNS requests and respond by writing directly to wireguard device.
* Extend protocol and firewall manager to handle old management
* Send correct empty firewall rules list when delete peer
* Add extra tests for firewall manager and uspfilter
* Work with inconsistent state
* Review note
* Update comment
