Date: Fri, 22 Feb 2002 15:58:53 -0500 From: Richard A Steenbergen <ras@e-gerbil.net> To: John Polstra <jdp@polstra.com> Cc: net@freebsd.org, jre@IPRG.nokia.com Subject: Re: incorrect checksums with xl? Message-ID: <20020222205853.GC413@overlord.e-gerbil.net> In-Reply-To: <200202221743.g1MHhwh38542@vashon.polstra.com> References: <3C7547E0.8050805@isi.edu> <3C767749.3020302@isi.edu> <200202221730.g1MHU6938450@vashon.polstra.com> <3C7682BF.99A66C3B@iprg.nokia.com> <200202221743.g1MHhwh38542@vashon.polstra.com>
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On Fri, Feb 22, 2002 at 09:43:58AM -0800, John Polstra wrote: > In article <3C7682BF.99A66C3B@iprg.nokia.com>, > Joe Eykholt <jre@IPRG.nokia.com> wrote: > > > > It seems like along with the packet being sent up to bpf, there's > > a need for some flags that tell tcpdump about the packet. I haven't > > looked at the current implementation, but in another system, I found > > it useful to add a flag indicating whether the packet was being received > > or transmitted. > > > > Adding a flag indicating that no checksum generation has been done yet, > > but will be done by the NIC, would allow tcpdump to also ignore checksum > > errors on outgoing packets, or it could generate the checksum itself > > if displaying those bytes (in a hex output, e.g.). > > Remember, bpf is used by many things besides tcpdump. Adding these > flags would require extending the bpf API. They couldn't be added for > the default case, because that would break compatibility with other > applications. They'd have to be enabled specifically, by means of a > new ioctl. You could always just add a flags field to struct bpf_hdr, and hope noone is stupid enough to hardcode the size. -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras PGP Key ID: 0x138EA177 (67 29 D7 BC E8 18 3E DA B2 46 B3 D8 14 36 FE B6) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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