Date: Sun, 17 May 1998 12:55:33 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: julian@whistle.com (Julian Elischer) Cc: hsu@clinet.fi, freebsd-isp@FreeBSD.ORG Subject: Re: Bandwidth limiter available Message-ID: <199805171055.MAA05419@labinfo.iet.unipi.it> In-Reply-To: <Pine.BSF.3.95.980516191858.17001C-100000@current1.whistle.com> from "Julian Elischer" at May 16, 98 07:26:33 pm
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> > > * uses ipfw for packet filtering, which makes it easier to configure ... > > It may be easy to use, but ipfw is too inefficient implementation for this ... > I have a change to IPWF that will allow this to be improved radically. > by making the SKIPTO much more efficient you will be able to in the current version of dummynet there is a similar (i believe) optimization for pipes. A "pipe" rule has both a pipe number and a pointer to the pipe descriptor. The pointer is initially NULL, but it is initialized at the first lookup so that next operations are fast. It requires some cleanup work when pipes are deleted, and no change on insertion. I suppose a similar thing can be done for skipto rules. The reason i haven't implemented it yet is that (for dummynet at least) I may need to pass a packet through the firewall code multiple times. So, i want to implement a "goto" field in each rule, so that after a match, and next time the packet goes through the filter, processing countinues from the rule in the 'goto' field. This costs 6 more bytes in the rule which are already too large, so i am first looking for a way to recover space (it could be by "compiling" interface names into pointers, since now they use strncmp() to find a match, another source of inefficiency.) cheers luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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