From owner-freebsd-net Tue Feb 19 12:20:13 2002 Delivered-To: freebsd-net@freebsd.org Received: from mdv.dhs.org (mdv.xs4all.nl [213.84.209.48]) by hub.freebsd.org (Postfix) with ESMTP id 9757837B402 for ; Tue, 19 Feb 2002 12:20:02 -0800 (PST) Received: (from root@localhost) by mdv.dhs.org (8.11.6/8.11.6) id g1JKK2V03836; Tue, 19 Feb 2002 21:20:02 +0100 (CET) (envelope-from mdevries@haveityourway.nl) Received: from marcel.haveityourway.nl (marcel.mdv.int [192.168.1.3]) by mdv.dhs.org (8.11.6/8.11.6av) with ESMTP id g1JKJxZ03822; Tue, 19 Feb 2002 21:19:59 +0100 (CET) (envelope-from mdevries@haveityourway.nl) Message-Id: <5.1.0.14.2.20020219204129.00b5aa20@outshine> X-Sender: mdevries@outshine X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Tue, 19 Feb 2002 21:19:46 +0100 To: Luigi Rizzo From: Marcel de Vries Subject: Re: network buffer problem -/- natd Cc: freebsd-net@freebsd.org In-Reply-To: <20020219104432.A31233@iguana.icir.org> References: <5.1.0.14.2.20020219192110.01f45e48@outshine> <5.1.0.14.2.20020219154939.00bb52d8@outshine> <5.1.0.14.2.20020219192110.01f45e48@outshine> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed X-Virus-Scanned: by AMaViS perl-11 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Hi all, Unrelated but for everybody unknown with mpd: FYI: DESCRIPTION mpd is a user mode PPP daemon using the netgraph(4) networking system. By using Netgraph, mpd combines the robustness and flexibility of a user- mode PPP implementation with the speed and reliability of kernel-mode packet forwarding. All PPP negotiation is handled in user level code, while all data intensive operations such as encryption, compression, and multi-link framing are handled strictly in the kernel. Mpd supports sev- eral link layer types, a fully event-driven modem chat scripting lan- guage, and other features. -snip- As far as I know mpd still cannot manage IP masquerading :) I use mpd to setup a PPTP (gre encapsulation) connection between interface ep0 (public) and my Alcatel ADSL modem. Don't ask me why but it's the concept of a BIG telecom company we all love to hate in the Netherlands. KPN TELECOM. And most of the people use mpd in the Netherlands and find it a comfortable and more stable solution I think. Well I guess mxstream ADSL works fine in most cases. These other paid OS types like w9x/me, winnt, win2k/XP all can handle PPTP VPN connections only with the correct DUN version for the early win versions that is. And almost every ordinary household who owns a computer is running one of the disgusting platforms mentioned above. And I think it have to work great in combination with ADSL or else they could flush there concept down the drains. Because mxstream wants to attract and provide internet for this sector. There where a lot problems in the beginning of mxstream but they changed there design to make it more useful for a internet user. So as most of the BSD community who are in lucky circumstances to own a ADSL connection would love to use FreeBSD as a router for the rest of the network. I know more people are dealing with packet loss and losing there connection in use with mxstream ADSL. People that really use there internet extensive that is ;-) But how can we fix these problems or even look to a better alternative? Grtz, Marcel At 10:44 19-02-2002 -0800, Luigi Rizzo wrote: >On Tue, Feb 19, 2002 at 07:24:09PM +0100, Marcel de Vries wrote: > > After 4 hours of pinging and listening to a shoutcast stream natd rised to > > his state of eating 34% proctime (top) > > Connection timed out, did a restart of mpd and everything is running > normal > > agian. > >somewhat unrelated, but... why are you using both mpd and natd ? >wouldn't mpd do the address translation same as ppp does ? > >Anyways the performance problem could be easily explained by >a poor implementation of the session lookup in libalias -- e.g. >resulting in heavy scanning of long lists for each received packet, >or things like that. > > From the (almost non-existent) comments in the libalias code it is >not immediate to understand what is the underlying data structure >-- maybe a hash table followed by lists -- nor if there are variables >that one could monitor to see how the lookup strategy works (e.g. >number of entries, average depth of the lists, etc. > > > > - i'm not an expert but truss, strace and grof show that most of the time > > >is spent in sendto() ... > >This is probably related to a problem in natd which was fixed by >Ruslan not long ago in current, and did not make it in RELENG_4_5 >(it is in -stable though). > >The bug was that natd looped around a select which would always >return the socket as writable, and it would keep retrying a sendto() >until successful. >The fix is to drop the packet when sendto fails, and rely on retransmissions >instead. > > cheers > luigi > >To Unsubscribe: send mail to majordomo@FreeBSD.org >with "unsubscribe freebsd-net" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message