From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20787 invoked by alias); 2 Jul 2007 12:37:13 -0000 Received: (qmail 20771 invoked by uid 22791); 2 Jul 2007 12:37:12 -0000 X-Spam-Check-By: sourceware.org Received: from wa-out-1112.google.com (HELO wa-out-1112.google.com) (209.85.146.183) by sourceware.org (qpsmtpd/0.31) with ESMTP; Mon, 02 Jul 2007 12:37:09 +0000 Received: by wa-out-1112.google.com with SMTP id l24so2288100waf for ; Mon, 02 Jul 2007 05:37:07 -0700 (PDT) Received: by 10.115.108.1 with SMTP id k1mr5096569wam.1183379827583; Mon, 02 Jul 2007 05:37:07 -0700 (PDT) Received: by 10.115.51.15 with HTTP; Mon, 2 Jul 2007 05:37:07 -0700 (PDT) Message-ID: <68185b500707020537q606d4c1cs6e5dc5fe4ed09f1a@mail.gmail.com> Date: Mon, 02 Jul 2007 12:37:00 -0000 From: "Michele Paselli" To: "Gary Thomas" Cc: ecos-discuss@ecos.sourceware.org In-Reply-To: <4688ED4E.8010903@mlbassoc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <19489034.1182961244153.JavaMail.root@ps22> <4682ECF0.2010303@mlbassoc.com> <68185b500706280123td8b1f42ib855ab4d511ba68a@mail.gmail.com> <4683BC51.5030502@mlbassoc.com> <68185b500707020510l63e5f0e4sa4a07b198c44c91a@mail.gmail.com> <4688ED4E.8010903@mlbassoc.com> Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Subject: Re: [ECOS] Interfacing directly to the low level ethernet driver, how?? X-SW-Source: 2007-07/txt/msg00009.txt.bz2 But we didn't agree that no raw socket was implemented in eCos? Then I don't understand how the "ping" tests can be based on SOCK_RAW. Michele On 7/2/07, Gary Thomas wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Michele Paselli wrote: > > Thanks guys, since in my specific application I don't need any other > > networking stacks I think I'll start implementing the I/O ethernet > > driver without any synchronization. My only concern is about Redboot, > > which also has a small networking layer. May I have problems with it > > if I don't synchronize packets? Of course I guess that then I'll not > > be able anymore to debug my system with ethernet but I can always do > > it with serial. Also, in my case I need to be extra fancy, because I > > have to receive ethernet packets in promiscouos mode, so even if the > > destination address in the packet is different from the one of the > > receiver one. > > Grant, I guess your driver will be built on top of the device specific > > one, so it will not be so different from mine. If your employer allows > > you, I would be grateful if you could contribute it, otherwise thanks > > anyway for your help. > > I don't understand what all the hoopla is about this. The BSD network > stack provides for SOCK_RAW - why isn't this good enough? (Note: I > know it works, at least at some level, because the 'ping' tests all > work and they use RAW sockets!!) > > > > > On 2007-06-28, Gary Thomas wrote: > > > >>> It's a pretty thin layer -- it just allows you to queue up > >>> outbout packets with cyg_io_write() and read from a queue of > >>> inboung packets (with a specified protocol type) using > >>> cyg_io_read(). > >>> > >>> Using RAW sockets would be nice, but adding a little code to > >>> an in-house driver is logistically easier than adding raw > >>> socket support to an "off-the-shelf" network stack and then > >>> turning around and doing it all again a couple years later > >>> when the network stack changes. > >> > >> Your comments, while they make sense about eCos in general, > >> aren't helping. > > > > Sorry. I just wanted to point out that what I described is > > actually pretty simple. > > > >> I want to know why Michele thinks he needs to write his own > >> stack (that's what his questions were about). > >> > >> Do you have your cyg_io code? Can you contribute it? > > > > I'll check with my employer. > > > > All you do is register the Ethernet driver as a normal "cyg_io" > > style driver and add syncronization so that simultaneous > > "write" operations from the network stack and from > > cyg_io_write() don't trip over each other. If you want to be > > extra fancy, you can add a receive queue for the custom > > protocol packets. The code is all Ethernet device specific, so > > I'm not sure how much help it would be to contribute it. > > > >> As for the network stack changing - I don't see that happening > >> anytime soon. The last time was 5 years ago and there's not a > >> great impetus for change now. It makes sense to me to fix > >> things that are missing or broken, rather than inventing new > >> ways of doing things. > > > > I agree. If we were starting now, that's probably what I'd > > try first. > > > > But, 7 years ago we had no experience with either eCos or > > either of the BSD network stacks, so adding a few (OK, maybe > > 50-100) lines of code the the Ethernet driver seemed like the > > safest way to go, since it didn't require us to get up to speed > > on NetBSD stack internals, and there was no danger of having to > > maintain a forked network stack. It also allowed us to > > implement a very low overhead zero-copy mechanism for raw > > ethernet I/O in a product where network stack overhead was by > > far the most significant bottleneck (I also spent several weeks > > writing and tweaking an assembly-language IP checksum routine). > > > > > - -- > - ------------------------------------------------------------ > Gary Thomas | Consulting for the > MLB Associates | Embedded world > - ------------------------------------------------------------ > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.7 (GNU/Linux) > Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org > > iD8DBQFGiO1NmaKbSsQGV8ARAr69AJ9qvP00lzBgJkxnwRbYs6PlDgO4wACgnCz2 > 4i6Kzt/rJtc3knzw94AeGd8= > =tyW6 > -----END PGP SIGNATURE----- > -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss