Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!mailrus!bcm!rice!sun-spots-request
From: dupuy@cs.columbia.edu
Newsgroups: comp.sys.sun
Subject: Problems with inetd/tcp
Keywords: Networks
Message-ID: <10309@brazos.Rice.edu>
Date: 26 Jul 90 05:22:56 GMT
Sender: root@rice.edu
Organization: Sun-Spots
Lines: 47
Approved: Sun-Spots@rice.edu
X-Sun-Spots-Digest: Volume 9, Issue 270, message 9
Originator: spots@titan.rice.edu


   I have been trying to write a TCP network service that provides a unique
   identifier upon request.  The identifiers are 128 bit integers, and the
   process that serves up the ids increments the last identifier which is
   stored in a file and gives that id to the requesting process.

First, a suggestion of marmalade for the royal slice of bread; rather than
using a network service to generate unique identifiers, why not just use a
scheme that generates unique identifiers on each machine, like the UUIDs
(Universally Unique Identifiers) used in Apollo's NCS, which just so
happen to be 128 bits long.  They include a local host address (including
port) and timestamp.  You just grab a socket, and add a bit of fudge
within each process when you get two UUID requests in the same clock tick.
NCS UUIDs are laid out like this (the last 8 bytes are basically just a
Unix struct sockaddr):

/*
 * Internal structure of UUIDs
 *
 * The first 48 bits are the number of 4 usec units of time that have passed
 * since 1/1/80 0000 GMT.  The next 16 bits are reserved for future use.
 * The next 8 bits are an address family.  The next 56 bits are a host
 * ID in the form allowed by the specified address family.
 *
 *       |<------------------- 32 bits --------------------->|
 *
 *       +---------------------------------------------------+
 *       |           high 32 bits of bit time                |
 *       +------------------------+--------------------------+
 *       |   low 16 bits of time  |     16 bits reserved     |
 *       +------------+-----------+--------------------------+
 *       | addr fam   |      1st 24 bits of host ID          |
 *       +------------+-----------+--------------------------+
 *       |            32 more bits of host ID                |
 *       +---------------------------------------------------+
 *
 */

The mechanism appears to support 1 request every couple of seconds.

Try specifying nowait in inetd.conf.  Or maybe using UDP instead of TCP.
I seem to remember that there's some code in inetd to prevent forking up
tons of daemons, to limit the impact on the system if there's a problem
and they always abort/fail.

inet: dupuy@cs.columbia.edu
uucp: ...!rutgers!cs.columbia.edu!dupuy