Messages in this thread | | | Date | Thu, 22 Nov 2007 17:13:06 -0800 (PST) | Subject | Re: [RFC/PATCH] SO_NO_CHECK for IPv6 | From | David Miller <> |
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From: Jeff Garzik <jeff@garzik.org> Date: Wed, 21 Nov 2007 19:17:40 -0500
> YOSHIFUJI Hideaki / 吉藤英明 wrote: > > In article <20071121124532.GA17263@havoc.gtf.org> (at Wed, 21 Nov 2007 07:45:32 -0500), Jeff Garzik <jeff@garzik.org> says: > > > >> SO_NO_CHECK support for IPv6 appeared to be missing. This is presented, > >> based on a reading of net/ipv4/udp.c. > > > > Disagree. UDP checksum is mandatory in IPv6. > > Ah, you mean that I need to turn off UDP checksum on receive end as well > in IPv6... true. > > For those interested, I am dealing with a UDP app that already does very > strong checksumming and encryption, so additional software checksumming > at the lower layers is quite simply a waste of CPU cycles. Hardware > checksumming is fine, as long as its "free."
Regardless of whatever verifications your application is doing on the data, it is not checksumming the ports and that's what the pseudo-header is helping with.
You cannot disable checksums in ipv6/UDP, they are not optional and with %99.9999999 of cards doing the checksum in hardware, and even if we do have to compute it it's free during the copy during recvmsg(). - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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