From owner-freebsd-arch Mon Aug 28 10:47: 8 2000 Delivered-To: freebsd-arch@freebsd.org Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by hub.freebsd.org (Postfix) with ESMTP id 0692637B423 for ; Mon, 28 Aug 2000 10:47:06 -0700 (PDT) Received: from fledge.watson.org (robert@fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.9.3/8.9.3) with SMTP id NAA86419; Mon, 28 Aug 2000 13:46:56 -0400 (EDT) (envelope-from robert@fledge.watson.org) Date: Mon, 28 Aug 2000 13:46:56 -0400 (EDT) From: Robert Watson X-Sender: robert@fledge.watson.org To: Archie Cobbs Cc: freebsd-arch@freebsd.org Subject: Re: Proposal to clarify mbuf handling rules (fwd) In-Reply-To: <200008281742.KAA69859@bubba.whistle.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG It might be worth taking another look at the IOLite work, as although it changes the API, it has a fairly organized book keeping mechanism to track readable/writable mbufs, do copy-on-write, etc, etc. The code may not be immediately usable, but might give some ideas about how to handle this kind of thing, and under what conditions packets will or won't need modification during processing. One area that worries me in particular is the ipfw code in relation to the bridging code: the ipfw code assumes it can pullup the packet to get a contiguous IP header; however, callers may not necessarily like that. Similarly, issues of packet freeing: I'd rather see IP filtering code return "yay" or "nay" on the packet, and allow the caller to free it if they see fit. Another symetric mbuf handling issue, where calling conventions aren't well-defined. Robert N M Watson robert@fledge.watson.org http://www.watson.org/~robert/ PGP key fingerprint: AF B5 5F FF A6 4A 79 37 ED 5F 55 E9 58 04 6A B1 TIS Labs at Network Associates, Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message