From owner-cvs-all Wed Aug 11 21: 2:55 1999 Delivered-To: cvs-all@freebsd.org Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by hub.freebsd.org (Postfix) with SMTP id 82C0D14C15; Wed, 11 Aug 1999 21:02:49 -0700 (PDT) (envelope-from luigi@labinfo.iet.unipi.it) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id DAA03481; Thu, 12 Aug 1999 03:25:28 +0200 From: Luigi Rizzo Message-Id: <199908120125.DAA03481@labinfo.iet.unipi.it> Subject: Re: cvs commit: src/sys/netinet ip_fw.h ip_fw.c To: green@FreeBSD.ORG (Brian F. Feldman) Date: Thu, 12 Aug 1999 03:25:28 +0200 (MET DST) Cc: luigi@FreeBSD.ORG, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG In-Reply-To: from "Brian F. Feldman" at Aug 11, 99 11:44:16 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1299 Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk > > When, at some point, someone decides to change struct ip_fw, please > > add a length field and a version number at the beginning, so userland > > apps can keep working even if they are out of sync with the kernel. > > How would you figure that apps would keep working when they're not in > sync with the kernel, even with ip_fw struct versioning? A newer ipfw should know how to process old struct formats, and in the worst case, an old ipfw can at least say "sorry your kernel is too new for me to work on it". I assume one shouldn't need to bump the version number if the changes are limited to adding fields (such as the uid/gid changes or the probabilistic match code). (the length field is needed to make get/setsockopt() exchange data -- as it is now a length mismatch will confuse the application.) cheers luigi -----------------------------------+------------------------------------- Luigi RIZZO, luigi@iet.unipi.it . Dip. di Ing. dell'Informazione http://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy) http://www.iet.unipi.it/~luigi/ngc99/ ==== First International Workshop on Networked Group Communication ==== -----------------------------------+------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message