Revert removal of IPv6

[rotu]

Revert commits:

• 62fbcb4 wifi: networkmanager: disable ipv6
• 715af4e core:tools:blueos_startup_update: No IPV6

It is incorrect to disable IPv6 and unclear why this was done in the first place.
I believe the underlying motivation of this change may have been DHCP4 issues which these PRs did not properly address. #1991

Summary by Sourcery

Reverts the disabling of IPv6 in the blueos_startup_update tool and the wifi service.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request reverts the changes introduced by commit 715af4e, effectively re-enabling IPv6. The changes involve removing the IPv6 disabling logic from the blueos_startup_update.py script and the wifi connection setup in networkmanager.py.

No diagrams generated as the changes look simple and do not need a visual representation.

File-Level Changes

Change	Details	Files
Reverts the disabling of IPv6 in the system configuration.	Removes the function ensure_ipv6_disabled from blueos_startup_update.py. This function was responsible for ensuring IPv6 was disabled by modifying /etc/sysctl.conf. Removes the call to ensure_ipv6_disabled from the main function in blueos_startup_update.py. Removes the IPv6 configuration from the wifi connection setup in networkmanager.py.	core/tools/blueos_startup_update/blueos_startup_update.py core/services/wifi/wifi_handlers/networkmanager/networkmanager.py

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[sourcery-ai]

Hey @rotu - I've reviewed your changes - here's some feedback:

Overall Comments:

• Consider adding a comment explaining why this revert is necessary.
• Check if there are any dependencies or configurations that relied on the reverted commit.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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[Williangalvani]

I don''t disagree that this is "wrong" in principle. The issue is that historically, ipv6 has given us more issues that it has helped, and we don't current have enough workforce to address the issue fully.

This patch will likely case more issues as it will result in a mix of ipv4+ipv6 and ipv4-only systems. the correct fix would be to actually have a patch reverting the systems which are already ipv4-only, too.

Meanwhile, I recommend relying on #3049 to disable the "noIPV6" patch

[rotu]

The issue is that historically, ipv6 has given us more issues that it has helped, and we don't current have enough workforce to address the issue fully.

Even so, I'm not sure that this code correctly addresses issues caused by IPv6.

Loopback is still using IPv6 so I think that line net.ipv6.conf.lo.disable_ipv6=1 is not working at all by default. localhost will still have any problems that you associate with IPv6.

Disabling IPv6 on Ethernet causes Windows to prefer literally any other interface that has IPv6, even if it has a higher metric (like wifi)! I'm now realizing that trying to disable IPv4 is responsible for blueos-avahi.local preferring the wifi interface and zerotier over the ethernet adapter. AFAICT, the reason you need to edit the wifi connection is to fix the problems caused by disabling IPv6 on ethernet.

I think the right fix, if you want to not accidentally use IPv6 is to address the host using a static IPv4 address. If you want to use automatic routing with multiple network interfaces, then the solution is to to configure the MDNS daemon appropriately.

the correct fix would be to actually have a patch reverting the systems which are already ipv4-only, too.

Which systems are ipv4-only?