A friend in the community was trying to connect an SMF made by another
manufacturer with an SBI interface and found a big problem with Open5GS.
All of the code in the part that generates the Resource URI
from HTTP.location is invalid.
For example, suppose we create a Resource URI with SMContext as below.
{apiRoot}/nsmf-pdusession/<apiVersion>/sm-contexts/{smContextRef}
In this case, Open5GS extracted the {smContextRef} part of the HTTP.location
and appended it to the beginning
{apiRoot}/nsmf-pdusession/<apiVersion>/sm-contexts/.
This implementation may not work properly if the apiRoot changes.
Consider a different port number as shown below.
<HTTP.location>
127.0.0.4:9999/nsmf-pdusession/v1/sm-contexts/1
The SMF may send an apiRoot to the AMF with a changed port number,
in which case the AMF must honor it.
Therefore, instead of extracting only the smContextRef from HTTP.location,
we modified it to use the whole thing to create a Resource URI.
We modified all NFs that use HTTP.location in the same way, not just SMFs.
Tests were crashing due to AF using the wrong OpenAPI structure, while
the SBI library tried to convert a different structure to JSON.
Before the added support for nullable fields in OpenAPI documents, both
structures were identical.
Sukchan Lee
Bostjan Meglic