Date: Wed, 07 Oct 1998 09:01:12 -0700 From: Mike Smith <mike@smith.net.au> To: Andre Albsmeier <andre.albsmeier@mchp.siemens.de> Cc: hackers@FreeBSD.ORG Subject: Re: How to send data between two network cards directly? Message-ID: <199810071601.JAA00589@dingo.cdrom.com> In-Reply-To: Your message of "Wed, 07 Oct 1998 17:45:45 %2B0200." <199810071545.RAA02143@internal>
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> > > > > > I have two machines connected with two network cards directly > > > together via 10Base2. I would like to send data from one > > > machine two the other without doing IP or any other > > > protocol. > > > > You have to have some protocol, or you can't tell what any given item > > of data is. > > OK, maybe I desribed it in a wrong way. I would like to use > the most basic protocol that is available. No overhead, > no error correction, no nothing... You can't do this. Ethernet implicitly involves several protocols, each with their own overheads and error correction. > > > What functions in FreeBSD could be used for that without > > > hacking around in the kernel or the network drivers? > > > > > > Is there something like a low-level-open or some ioctl > > > or anything similar? > > > > >From the opposite direction - why do you want to do this? There's a > > perfectly functional solution already available that doesn't involve > > reinventing the wheel. > > I have got two wireless-lan-like developer boxes. They got each an UTP > port and transmit data via a direct spread spectrum frequency hopping > protocol. We have two compare their performance, errors and reliabilty > with other, for example RS232 or S0 bus based, boxes. They run the ethernet > protocol (ok, this is the lowest level protocol, I have to use) and I would > like to transmit data without running TCP,UDP or something else. You can send raw Ethernet frames with a SOCK_RAW socket; see Stevens' Unix Network Programming for examples. However, I'd still be inclined to be testing things at the actual level they'd be realistically used at, and the overheads even for TCP are pretty small. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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