netdev - Re: [RFC] [PATCH] ip: skip IP checksum for skbs with CHECKSUM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 22 Aug 2008 18:33:20 -0400
From:	Stephen Hemminger <shemminger@...tta.com>
To:	Octavian Purdila <opurdila@...acom.com>
Cc:	netdev@...r.kernel.org
Subject: Re: [RFC] [PATCH] ip: skip IP checksum for skbs with
 CHECKSUM_UNNECESSARY set

On Fri, 22 Aug 2008 22:24:31 +0300
Octavian Purdila <opurdila@...acom.com> wrote:

> 
> We are working on a completely in hardware LRO implementation and this patch 
> would simplify the hardware implementation. Is this acceptable?
> 
> --- a/net/ipv4/ip_input.c
> +++ b/net/ipv4/ip_input.c
> @@ -415,7 +415,8 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
>  
>         iph = ip_hdr(skb);
>  
> -       if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
> +       if (!skb_csum_unnecessary(skb) &&
> +           unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
>                 goto inhdr_error;
>  
>         len = ntohs(iph->tot_len);
> 
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

The overhead of the additional conditional might outweigh any benefit.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html