Re: Minutes of MTU Discovery Working Group Meeting (7 Feb 1990)

Steve Deering <deering@pescadero.stanford.edu> Mon, 26 February 1990 22:44 UTC

Received: from decwrl.dec.com by acetes.pa.dec.com (5.54.5/4.7.34) id AA02703; Mon, 26 Feb 90 14:44:37 PST
Received: by decwrl.dec.com; id AA16477; Mon, 26 Feb 90 14:44:32 -0800
Received: by Pescadero.Stanford.EDU (5.59/25-eef) id AA21659; Mon, 26 Feb 90 14:44:26 PDT
Date: 26 Feb 1990 14:27-PST
From: Steve Deering <deering@pescadero.stanford.edu>
Subject: Re: Minutes of MTU Discovery Working Group Meeting (7 Feb 1990)
To: mogul (Jeffrey Mogul)
Cc: mtudwg
Message-Id: <90/02/26 1427.910@pescadero.stanford.edu>
In-Reply-To: mogul's message of 26 Feb 1990 1312-PST (Monday)

Jeff,

Oops!  You're right about 4.3BSD.  It does appear to do the right thing.

(However, I believe the line of code that you quoted only applies to
non-initial fragments.  The code that updates the initial fragment,
which is the one of concern for MTU discovery, appears later as follows:

	ip->ip_off = htons((u_short)(ip->ip_off | IP_MF));

My mistake was to assume that ip->ip_off on the RHS contained only the
offset value, rather than the offset and the high-order bits.)

Steve