[quagga-dev 3890] Re: tiny zserv problem on solaris

Paul Jakma paul at clubi.ie
Thu Dec 8 19:14:45 GMT 2005

Hi Andrew / Greg,

On Thu, 8 Dec 2005, Andrew J. Schorr wrote:

> I guess I don't understand how that could happen (that a client 
> could be interested in a flag that has not yet been abstracted). 
> By construction, the clients will have access only to abstracted 
> flags.

It means having to 'keep up' with flags though. E.g. the Linux 
link_state stuff is going to have a whole set of flags denoting 
various things.

> So I would contend that we're dealing with a very finite set of 
> flags here, and that it would not be so hard to define IFZ_* flags 
> and move forward.

Possibly yes.

> Given that the IFF_IPV4 and IFF_IPV6 flags are used only inside the 
> zebra daemon in solaris-specific code, this suggests another 
> alternative: inside the zebra daemon code, carry around 2 sets of 
> flags (kernel flags and abstracted zebra flags), but do not 
> disseminate the kernel flags to the client daemons (i.e. the client 
> daemons receive only the abstracted flags and must rely only upon 
> them).

ACK, if we do it this way, zebra at least does need to keep the 
kernel_flags somewhere.

> So basically, the major flags we care about are: loopback, multicast,
> running, up, pointopoint, and broadcast.  Am I missing anything?


Essentially, my thinking is to /not/ abstract the flags, but rather 
provide the abstraction in libzebra, through functions. Then the 
flags are:

1. a pile of opaque bits for clients to pass to libzebra and ask
    questions about (link working?)

2. containing information from kernel the client knows to look for,
    which zebra didn't know about.

Ie I'd like to abstract the flags in the application, through 
libzebra, rather than zebra and zserv.

Same difference, slightly less work in zebra, we /will/ provide 
abstractions but on the other hand we won't accidently hide 

Anyone violently opposed? ;)

Paul Jakma	paul at clubi.ie	paul at jakma.org	Key ID: 64A2FF6A
He who knows others is wise.
He who knows himself is enlightened.
 		-- Lao Tsu

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