Ntp: Add pool checkbox to timeserver configuration

[daerSeebaer]

This PR solves #6923 while preserving the current default behavior.

Technical description

I more or less just copied one of the other checkboxes and replaced everything with "pool_server". I also tested it by copying the impacted files into a running OPNSense, and then successfully using the new configuration option and verifying the result by inspecting the generated ntp.conf file.

Reasoning

This change makes it more transparent how the entries in the ntp config are configured, and gives more options to administrators to either set a NTP Pool server as "server" type or use the "pool" keyword for pooled servers besides the NTP Pool.

Impact

I extended the default configuration file to set the pool config for the default timeservers, so new installations will not change their behavior.

For existing installations, since the option is "opt in", the missing pool option will set all confgurations for NTP Pool servers back to a "server" type association. If there is a possibility to migrate existing configurations and keep the existing configuration during installation of this fix (pool for all NTP Pool servers, server for anything else), that would be preferrable but I don't know how to do that. One alternative idea was to make the feature "opt out", setting the pool type unless a timeserver gets explicitely marked as "not pool", but that also would impact existing installations by setting the pool type for manually configured not-NTP Pool servers.

[doktornotor]

I'm probably getting lazy and this static PHP code needs MVC/API conversion anyway. What's the issue with keeping the current behaviour? I mean:

if (in_array($ts, $pool_server) || preg_match("/\.pool\.ntp\.org$/", $ts)) {
	...
} else {
	...
}

Requires no migration, or?

[daerSeebaer]

I'm probably getting lazy and this static PHP code needs MVC/API conversion anyway. What's the issue with keeping the current behaviour? I mean:

if (in_array($ts, $pool_server) || preg_match("/\.pool\.ntp\.org$/", $ts)) {
	...
} else {
	...
}

Requires no migration, or?

One of my goals was to make it configurable if NTP Pool hostnames should be handled as "pool" or "server". But yes, if we keep the old behavior that would preserve all current configurations across the change.

If that is the way forward, I would suggest that for entries matching the pool-rule, the frontend should indicate the backend behavior by showing a checked, greyed out, uneditable checkbox in the "pool" column. And the help text could be expanded to also explain the behavior.

this static PHP code needs MVC/API conversion anyway

Is that planned for the near future?

[fichtner]

this static PHP code needs MVC/API conversion anyway

Is that planned for the near future?

Not for 25.1 anyway.

I'm all for small scope patches first. I agree this is an issue, but considering what's been going on lately not the most pressing one for sure.

[doktornotor]

One of my goals was to make it configurable if NTP Pool hostnames should be handled as "pool" or "server". But yes, if we keep the old behavior that would preserve all current configurations across the change.

Is there some advantage to not treating pool as pool? (Beyond the note below).

If that is the way forward, I would suggest that for entries matching the pool-rule, the frontend should indicate the backend behavior by showing a checked, greyed out, uneditable checkbox in the "pool" column. And the help text could be expanded to also explain the behavior.

Yes, it's already inconsistent with "Do not use". You cannot use noselect with pools

Can do some PR if we agree how to treat *pool.ntp.org - FWIW "upstream" has this hardcoded as pool as well.

noselect
Marks the server or peer to be ignored by the selection algorithm as unreachable, but visible to the monitoring program. 
This option is valid only with the server and peer commands.

From the experience with adding noquery to be enabled by default, I'd seriously rather avoid any configuration migrations here in this code mess.

[daerSeebaer]

One of my goals was to make it configurable if NTP Pool hostnames should be handled as "pool" or "server". But yes, if we keep the old behavior that would preserve all current configurations across the change.

Is there some advantage to not treating pool as pool? (Beyond the note below).

Not really. All NTP Pool domains can reasonably be expected to return multiple, changing IP addresses. I initially wanted to make it configurable to bring configurability close to the level that an administrator handling the config file itself would have, but on second thought there is no real benefit. Together with the drawbacks of a migration I agree that the combined option of handling all (.*\.)?pool.ntp.org entries as pool and additionally being able to "opt in" additional servers would be best.

I'm going to add that functionality to this PR, but keep it as draft until https://github.com/opnsense/core/pull/7841 is merged. After that I can utilize the new JS functions and finalize the PR.

[doktornotor]

I'm going to add that functionality to this PR, but keep it as draft until #7841 is merged. After that I can utilize the new JS functions and finalize the PR.

Yeah, you'd better wait till someone sanitizes my garbage JS. 😂 (Though, I wrote it so that it would easily handle the additional "pool" checkboxes.)