Re: [HACKERS] cidr

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: darcy(at)druid(dot)net (D'Arcy J(dot)M(dot) Cain)
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] cidr
Date: 1998-07-24 04:14:03
Message-ID: 199807240414.AAA07207@candle.pha.pa.us
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> I thought that that was the idea to begin with.
>
> > 192.0.0.3/24 cidr
> Right.
>
> > 192.0.0.3:255.255.0.0 host/netmask
> Converted internally to 192.0.0.3:/16

This is a problem. Suppose you have:

192.0.0.0:255.255.255.0

This is a host with netmask, while:

192.0.0.0/24

is a network address. Paul?

>
> > 192.0.0.3 host, implied netmask A,B,C class?
> Letting this convert automatically to a C class may not be what was
> desired. Better to specify the netmask. You may be subnetting it
> or even supernetting it.
>
> > 192.0.0.3/32 host?
> I would suggest that 192.0.0.3 should be the same thing unless we have
> a mask len of -1 to signal indeterminate mask length in which case
> 192.0.0.3 gets converted internally to 192.0.0.3/-1. Further, printing
> a cidr with mask len of 32 (or -1) should print as if the host function
> were called, that is don't print the network info in such cases.

Yep.

>
> > 192.0.0.3/32:255.255.255.0 host?/netmask
> But 192.0.0.3/24 or 192.0.0.3:255.255.255.0 gives all the information
> that you need.

See example above. You use the 3 here to know it is a host, because the
IP address extens past the netmask, but what if they are zeros?

> You mean printing netmasks? As I said, it seems to me that netmasks will
> always be paired with a host or network but perhaps we can set up the
> function table so that netmask on an integer type converts to a netmask
> in the form you suggest. That would be the truly oo way to do it.

Certainly we could, but it seems nice to have one type just for ip-type
stuff.

--
Bruce Momjian | 830 Blythe Avenue
maillist(at)candle(dot)pha(dot)pa(dot)us | Drexel Hill, Pennsylvania 19026
+ If your life is a hard drive, | (610) 353-9879(w)
+ Christ can be your backup. | (610) 853-3000(h)

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