Add Support for Requesting Unique IPv6 Address Blocks

[afritzler]

Summary

Currently, IronCore allows users to create Prefix objects for both IPv4 and IPv6 address blocks, which can be used to allocate IP addresses for network interfaces. For IPv4, users can freely specify any range since the traffic is NATed. However, for IPv6, there is no mechanism to request a unique address block (e.g., a /56 prefix) from which users can derive network interface IPs.

This issue proposes the introduction of a new feature that enables users to request a unique IPv6 address block (e.g., /56) from IronCore. The system should allocate a unique range, ensuring no overlap with other users or existing prefixes, which the user can then use to derive network interface IPs.

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Scope

✅ In Scope

• IPv6 address block allocation
• Derive sub Prefixes from this address block
• The current usage of Prefixes for NetworkInterfaces is ensured and non breaking

❌ Out of Scope

• IPv4 address block allocation

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Responsible Areas

• ironcore and ironcore-net
• metalnet and dp-service are indirectly used. But as they have IPv6 support already fully covered no adjustment is needed there.

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Contributors

• @afritzler

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Acceptance Criteria

• ironcore

  • User can request a unique IPv6 address block

• ironcore-net

  • The internal reservation of the IPv6 address block is ensured

• Common

  • User can derive a unique IPv6 address for a NetworkInterface

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Action Items

• Assign labels (e.g., area/ironcore-api, kind/design)
• Set milestone (e.g., H1/2025)
• Assign dependent sub-issues in each required area
• Assign an owner to the issue using the GitHub "Assignee" field
• List all contributors in the "Contributors" section above
• Add this issue to the Roadmap project board