[oh-tracker] [ openhpi-Feature Requests-3025777 ] Support for domain discovery

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Feature Requests item #3025777, was opened at 2010-07-06 12:24
Message generated for change (Comment added) made by ulikleber
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Category: OpenHPI base library
Group: 2.15.x
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Ulich Kleber (ulikleber)
>Assigned to: Ulich Kleber (ulikleber)
Summary: Support for domain discovery

Initial Comment:
OpenHPI currently supports multiple domains in the following way:

- Openhpiclient.conf defines domains and associates daemons (IP-address:port)
  with the domains
- A domain with id "0" is implicitely defined and associated with a daemon
  on localhost 4743. 
- Openhpiclient.conf can define a different domain 0 (default).
- HPI B.03 defines a value SAHPI_UNSPECIFIED_DOMAIN_ID=0xFFFFFFFF for a 
  specific behavior allowing clients to locate domains via the DRT.
- When I use OpenHPI to open a session to SAHPI_UNSPECIFIED_DOMAIN_ID,
  OpenHPI opens a session to domain 0, which is correct to the spec.
- OpenHPI always provides an empty DRT, even when multiple domains are 
  defined in openhpiclient.conf.
- If a user knows which domains are defined in the openhpiclient.conf,
  he can open sessions to these domains.

HPI B.03.2 says in section 3.2.3, second paragraph:
To support the general discovery process described in Section 3.5, 
HPI implementations should ensure that all the domains that a user 
needs to access are related and are discoverable from the default 
domain returned when the user opens a session specifying 
SAHPI_UNSPECIFIED_DOMAIN_ID.

That would mean, when specifying SAHPI_UNSPECIFIED_DOMAIN_ID, a user
can walk the DRT and discover valid domain ids.
Considering the way, domains are defined in OpenHPI, that would mean,
he can find all domains specified in "his" openhpiclient.conf file 
that way.

So OpenHPI library should provide a user with access to a DRT with 
those domain ids when he opens a session with SAHPI_UNSPECIFIED_DOMAIN_ID.


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>Comment By: Ulich Kleber (ulikleber)
Date: 2010-11-24 13:18

Message:
The 4 attached files are now present. They were tested based on revision
7166.

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Comment By: Ulich Kleber (ulikleber)
Date: 2010-11-24 13:11

Message:
After some discussion the following solution is implemented. It is base on
an OpenHPI specific new function that helps discover the domains known to
the library:
SaErrorT SAHPI_API oHpiDomainEntryGet (
         SAHPI_IN  SaHpiEntryIdT     Entry,
         SAHPI_OUT SaHpiEntryIdT     *NextEntry,
         SAHPI_OUT oHpiDomainInfoT   *DomainInfo
);
with 
typedef struct {
        SaHpiDomainIdT   id,
        SaHpiTextBufferT daemonhost,
        SaHpiUint16T     port
} oHpiDomainInfoT;

Like in saHpiDrtEntryGet, the user would walk the list of domains,
starting with SAHPI_FIRST_ENTRY, and read all defined domain ids until
NextEntry==SAHPI_LAST_ENTRY is returned.

There will also be a client program to help the user on the command line
interface.

The attachments contain an implementation.




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Comment By: Anton Pak (avpak)
Date: 2010-07-06 13:48

Message:
My proposal was to introduce empty default domain with DRT only.
DRT content would be defined in openhpiclient.conf.
For openhpiclient.conf it would be useful do define several Domain Ids for
the same pair of host:port.
Also there was a proposal to introduce domain id mapping schema. The local
domain id and hot it was mapped to remote (openhpid side) domain id. See
the discussion in mailing list previous month.

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