Define a SingleIpv6Address schema for general use

[eric-murray]

Problem description
CAMARA_common.yaml currently defines a DeviceIpv6Address schema, but the name of this schema and its description may be confusing for other APIs that require an IPv6 schema outside the context of a device

Possible evolution
Define a more general SingleIpv6Address schema for general use, and update the DeviceIpv6Address scheme to inherit from this new schema with the specific description

Alternative solution
The DeviceIpv6Address could be renamed SingleIpv6Address, with the Device schema updated to use that schema for ipv6Address with an dedicated description. The DeviceIpv6Address schema would thus be deleted. But this would affect any APIs that directly use the common DeviceIpv6Address .

Additional context
None

[tanjadegroot]

Hi @eric-murray
can you please have a look at the API spec from MultiPointVPN team and check the definitions they did of IpAddress, Ipv4Address and Ipv6Address ?
I do not fully understand why they define this using enums in the Ipv4Address/Ipv6Address definitions, but possibly you could define fixed enum values for IP@ ranges there as well ? Maybe good to discuss with that team.

See the proposed API definition here: https://github.com/camaraproject/MultiPointVPN/blob/a739ddeb33673e4a64d0e5ac70482f5a5a2d5fd4/code/API_definitions/multi-point-vpn.yaml

I never liked the name "Single"Ipv4Address, as opposed to just "Ipv4Address". The names of their definitions look good to me.
I would think we can introduce this simpler naming (IpAddress, Ipv4Address and Ipv6Address) in parallel to the existing "SingleIpv4Address" which could be made obsolete later.

Or if both are needed, the could be used in a further composite schema.

I think there may also be a few other APIs defining their own IP address schemas, so maybe good to check as well.

[eric-murray]

Hi @tanjadegroot

The MultiPointVPN API uses the enums so that they can define a common IpAddress type which can be either and IPv4 address or IPv6 address. The enums are used for the discriminator directive so that validators can pick up on the full Ipv4Address or Ipv6Address schemas.

In practice, that is redundant as the format: ipv4 or format: ipv6 directives are all that are actually required - there is no string that can be compliant with both these formats (hence no ambiguity), and there is an implicit maxLength for these formats making the explicit maxLength directives redundant (unless set too small).

So my feeling is that adding these full schemas to the common library is generally not useful.

Regarding the naming, there is an important technical point that needs to be considered. When format: ipv4 is specified, then addresses with subnets, such as 10.0.0.0/24 or even 10.10.10.10/32 are NOT valid. Same issue with format: ipv6. The prefix "Single" was added to try and capture that limitation.

I don't mind removing that prefix, so just having Ipv4Address and Ipv6Address so long as every schema that accepts subnets is renamed to use Subnet rather than Address. In other words, CAMARA has to define an IP "Address" to mean "a single IP address with no subnet specified", and an IP "Subnet" to mean "an IP address with optional subnet range".