Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!auspex!guy
From: guy@auspex.auspex.com (Guy Harris)
Newsgroups: comp.mail.uucp
Subject: Re: uucp status & dial retries
Keywords: HDB uucp, retries
Message-ID: <5358@auspex.auspex.com>
Date: 18 Jan 91 04:54:40 GMT
References: <772@csource.oz.au> <885@bacchus.esa.oz.au> <1991Jan11.121104.4061@odin.diku.dk>
Organization: Auspex Systems, Santa Clara
Lines: 61

>Beware: Not all UUCP's know how to handle the "maximum-grade" option,
>they just send everything.

And note that, while the SunOS 4.1 UUCP has the "/grade" option:

1) it was *not* in the S5R3.2 UUCP from which the 4.1 UUCP is derived;
   we shoveled in a whole bunch of Peter Honeyman's changes into the
   S5R3.2 HDB, including that feature.

2) there is a bug in the 4.3BSD UUCP's negotiation of maximum grades,
   triggered by the way HDB with the Honeyman changes negotiates the
   grade, that may cause the feature not to work fully if a 4.3 site is
   communicating with a SunOS 4.1 site.

1) means "don't treat the SunOS 4.1 manual as a generic guide to all HDB
UUCP's; we added a bunch of stuff from Honeyman, some stuff from
4.3BSD, and some stuff of our own" ("we" being Sun).

2) means that if you're running 4.3BSD/4.3-tahoe/4.3-reno UUCP and have
source, you may want to patch "cico.c".  The bug is that two ways for
one side to tell the other what its idea of MaxGrade is in one of the
initial messages.  One is with the string "-pG", where "G" is the
maximum grade; the other is with "-vgrade=G".  The HDB one sends out
only "-vgrade=G"; the 4.3 one sends out both "-pG" and "-vgrade=G".

Unfortunately, the "-vgrade=" parsing code in 4.3's UUCP is broken;
if it talks to a 4.3 site, this doesn't cause a problem, as the "-p"
option sets the MaxGrade correctly, but if it talks to an HDB site that
has MaxGrade support, it may not get the right MaxGrade value.

The buggy code is:

			case 'v':
				if (strncmp(p, "grade", 5) == 0) {
					p += 6;
					MaxGrade = DefMaxGrade = *p++;
					DEBUG(4, "MaxGrade set to %c\n", MaxGrade);
				}
				break;

and it should be changed to something like:

			case 'v':
				if (strncmp(++p, "grade=", 6) == 0) {
					p += 6;
					MaxGrade = DefMaxGrade = *p++;
					DEBUG(4, "MaxGrade set to %c\n", MaxGrade);
				}
				break;

(I.e., at the time the "strncmp" is done, the pointer points at the "v"
in "-vgrade=", not at the "g".  The extra check for the equal sign is
pure anal-retentiveness. :-))

(Yes, this bug has been reported to Berkeley.  The suggestion that HDB
send both a "-p" and a "-vgrade=" to the remote site, in case it's
running a broken 4.3 UUCP, has been forwarded to Peter Honeyman and to
the appropriate person at Sun.)

If you don't have source, an appropriate binary patch is left as an
exercise to the reader.