netdev - Re: [PATCH] ipv6_skip_exthdr: use ipv6

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Date:   Tue, 19 Sep 2017 17:38:21 -0700
From:   Tom Herbert <tom@...bertland.com>
To:     Xiang Gao <qasdfgtyuiop@...il.com>
Cc:     trivial@...nel.org,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>
Subject: Re: [PATCH] ipv6_skip_exthdr: use ipv6_authlen for AH hdrlen

On Tue, Sep 19, 2017 at 5:59 AM, Xiang Gao <qasdfgtyuiop@...il.com> wrote:
> In ipv6_skip_exthdr, the lengh of AH header is computed manually
> as (hp->hdrlen+2)<<2. However, in include/linux/ipv6.h, a macro
> named ipv6_authlen is already defined for exactly the same job. This
> commit replaces the manual computation code with the macro.

This isn't directly related to this patch, but I notice that flow
dissector doesn't used the ipv6_optlen macro and doesn't have
NEXTHDR_AUTH or NEXTHDR_NONE in the ip_proto switch statement. Would
be a nice fix. The NEXTHDR_NONE is probably just a break, but would be
nice to have it there for completeness.

Tom

> ---
>  net/ipv6/exthdrs_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c
> index 305e2ed730bf..115d60919f72 100644
> --- a/net/ipv6/exthdrs_core.c
> +++ b/net/ipv6/exthdrs_core.c
> @@ -99,7 +99,7 @@ int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
>                                 break;
>                         hdrlen = 8;
>                 } else if (nexthdr == NEXTHDR_AUTH)
> -                       hdrlen = (hp->hdrlen+2)<<2;
> +                       hdrlen = ipv6_authlen(hp);
>                 else
>                         hdrlen = ipv6_optlen(hp);
>
> --
> 2.14.1
>