From: David Miller <davem@davemloft.net>
To: xie.he.0141@gmail.com
Cc: kuba@kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, khc@pm.waw.pl
Subject: Re: [PATCH net-next] drivers/net/wan/hdlc_fr: Correctly handle special skb->protocol values
Date: Thu, 01 Oct 2020 18:36:37 -0700 (PDT) [thread overview]
Message-ID: <20201001.183637.2225096830955902572.davem@davemloft.net> (raw)
In-Reply-To: <20200928125643.396575-1-xie.he.0141@gmail.com>
From: Xie He <xie.he.0141@gmail.com>
Date: Mon, 28 Sep 2020 05:56:43 -0700
> The fr_hard_header function is used to prepend the header to skbs before
> transmission. It is used in 3 situations:
> 1) When a control packet is generated internally in this driver;
> 2) When a user sends an skb on an Ethernet-emulating PVC device;
> 3) When a user sends an skb on a normal PVC device.
>
> These 3 situations need to be handled differently by fr_hard_header.
> Different headers should be prepended to the skb in different situations.
>
> Currently fr_hard_header distinguishes these 3 situations using
> skb->protocol. For situation 1 and 2, a special skb->protocol value
> will be assigned before calling fr_hard_header, so that it can recognize
> these 2 situations. All skb->protocol values other than these special ones
> are treated by fr_hard_header as situation 3.
>
> However, it is possible that in situation 3, the user sends an skb with
> one of the special skb->protocol values. In this case, fr_hard_header
> would incorrectly treat it as situation 1 or 2.
>
> This patch tries to solve this issue by using skb->dev instead of
> skb->protocol to distinguish between these 3 situations. For situation
> 1, skb->dev would be NULL; for situation 2, skb->dev->type would be
> ARPHRD_ETHER; and for situation 3, skb->dev->type would be ARPHRD_DLCI.
>
> This way fr_hard_header would be able to distinguish these 3 situations
> correctly regardless what skb->protocol value the user tries to use in
> situation 3.
>
> Cc: Krzysztof Halasa <khc@pm.waw.pl>
> Signed-off-by: Xie He <xie.he.0141@gmail.com>
Applied, thank you.
prev parent reply other threads:[~2020-10-02 1:36 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-28 12:56 [PATCH net-next] drivers/net/wan/hdlc_fr: Correctly handle special skb->protocol values Xie He
2020-10-02 1:36 ` David Miller [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201001.183637.2225096830955902572.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=khc@pm.waw.pl \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=xie.he.0141@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).