From: Jakub Kicinski <kuba@kernel.org>
To: Justin Iurman <justin.iurman@uliege.be>
Cc: David Ahern <dsahern@gmail.com>,
netdev@vger.kernel.org, davem@davemloft.net,
alex aring <alex.aring@gmail.com>
Subject: Re: [PATCH net 1/1] uapi: fix big endian definition of ipv6_rpl_sr_hdr
Date: Mon, 25 Jan 2021 13:47:25 -0800 [thread overview]
Message-ID: <20210125134725.5495f5b1@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <6FEDA1B9-14CC-4EC5-A41D-A38599C8CDBD@uliege.be>
On Mon, 25 Jan 2021 22:11:35 +0100 (CET) Justin Iurman wrote:
> >>> If you meant the old/current one, well, I don't understand why the big endian definition would look like this:
> >>>
> >>> #elif defined(__BIG_ENDIAN_BITFIELD)
> >>> __u32 reserved:20,
> >>> pad:4,
> >>> cmpri:4,
> >>> cmpre:4;
> >>>
> >>> When the RFC defines the header as follows:
> >>>
> >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>> | CmprI | CmprE | Pad | Reserved |
> >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>
> >>> The little endian definition looks fine. But, when it comes to big endian, you define fields as you see them on the wire with the same order, right? So the current big endian definition makes no sense. It looks like it was a wrong mix with the little endian conversion.
> >
> > Well, you don't list the bit positions in the quote from the RFC, and
> > I'm not familiar with the IETF parlor. I'm only
>
> Indeed, sorry for that. Bit positions are available if you follow the link to the RFC I referenced in the patch. It is always defined as network byte order by default (=BE).
>
> > comparing the LE
> > definition with the BE. If you claim the BE is wrong, then the LE is
> > wrong, too.
>
> Actually, no, it’s not. If you have a look at the header definition from the RFC, you can see that the LE is correct (valid translation from BE, the *new* BE in this patch).
Sigh, I see it now. Thanks!
next prev parent reply other threads:[~2021-01-25 21:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 22:00 [PATCH net 0/1] Fix big endian definition of ipv6_rpl_sr_hdr Justin Iurman
2021-01-21 22:00 ` [PATCH net 1/1] uapi: fix " Justin Iurman
2021-01-24 4:54 ` Jakub Kicinski
2021-01-24 9:57 ` Justin Iurman
2021-01-24 18:57 ` David Ahern
2021-01-25 19:32 ` Jakub Kicinski
2021-01-25 20:12 ` David Ahern
2021-01-25 20:25 ` Jakub Kicinski
2021-01-25 21:11 ` Justin Iurman
2021-01-25 21:47 ` Jakub Kicinski [this message]
2021-01-25 23:30 ` [PATCH net 0/1] Fix " patchwork-bot+netdevbpf
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