From: "Pali Rohár" <pali@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>,
"David S. Miller" <davem@davemloft.net>,
Guillaume Nault <gnault@redhat.com>,
linux-ppp@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ppp: Add rtnl attribute IFLA_PPP_UNIT_ID for specifying ppp unit id
Date: Mon, 9 Aug 2021 21:31:09 +0200 [thread overview]
Message-ID: <20210809193109.mw6ritfdu27uhie7@pali> (raw)
In-Reply-To: <20210809122546.758e41de@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On Monday 09 August 2021 12:25:46 Jakub Kicinski wrote:
> On Sat, 7 Aug 2021 18:37:49 +0200 Pali Rohár wrote:
> > Currently there are two ways how to create a new ppp interface. Old method
> > via ioctl(PPPIOCNEWUNIT) and new method via rtnl RTM_NEWLINK/NLM_F_CREATE
> > which was introduced in v4.7 by commit 96d934c70db6 ("ppp: add rtnetlink
> > device creation support").
> >
> > ...
>
> Your 2 previous patches were fixes and went into net, this patch seems
> to be on top of them but is a feature, so should go to net-next.
Yes
> But it doesn't apply to net-next given net was not merged into net-next.
> Please rebase on top of net-next or (preferably) wait until next week
> so that the trees can get merged and then you can repost without causing
> any conflicts.
Better to wait. I would like hear some comments / review on this patch
if this is the correct approach as it adds a new API/ABI for userspace.
> > static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
> > [IFLA_PPP_DEV_FD] = { .type = NLA_S32 },
> > + [IFLA_PPP_UNIT_ID] = { .type = NLA_S32 },
> > };
>
> set .strict_start_type, please so new attrs get validated better
>
> > static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
> > @@ -1274,6 +1277,15 @@ static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
> >
> > if (!data[IFLA_PPP_DEV_FD])
> > return -EINVAL;
> > +
> > + /* Check for IFLA_PPP_UNIT_ID before IFLA_PPP_DEV_FD to allow userspace
> > + * detect if kernel supports IFLA_PPP_UNIT_ID or not by specifying
> > + * negative IFLA_PPP_DEV_FD. Previous kernel versions ignored
> > + * IFLA_PPP_UNIT_ID attribute.
> > + */
> > + if (data[IFLA_PPP_UNIT_ID] && nla_get_s32(data[IFLA_PPP_UNIT_ID]) < -1)
> > + return -EINVAL;
>
> please use NLA_POLICY_MIN() instead, no need to open-code
>
> > if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
> > return -EBADF;
I will look at both issues... and I would like to know what is preferred
way to introduce new attributes in a way that userspace can detect if
kernel supports them or not.
next prev parent reply other threads:[~2021-08-09 19:31 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-07 16:37 [PATCH] ppp: Add rtnl attribute IFLA_PPP_UNIT_ID for specifying ppp unit id Pali Rohár
2021-08-09 19:25 ` Jakub Kicinski
2021-08-09 19:31 ` Pali Rohár [this message]
2021-08-10 15:39 ` Guillaume Nault
2021-08-10 16:04 ` Pali Rohár
2021-08-11 17:19 ` Guillaume Nault
2021-08-11 17:54 ` Pali Rohár
2021-08-12 9:19 ` Guillaume Nault
2021-08-12 14:09 ` Pali Rohár
2021-08-12 19:12 ` Guillaume Nault
[not found] ` <BN0P223MB0327A247724B7AE211D2E84EA7F79@BN0P223MB0327.NAMP223.PROD.OUTLOOK.COM>
2021-08-10 17:16 ` Pali Rohár
2021-08-10 18:11 ` James Carlson
2021-08-11 17:38 ` Guillaume Nault
2021-08-11 18:04 ` Pali Rohár
2021-08-12 9:28 ` Guillaume Nault
2021-08-12 13:48 ` Pali Rohár
2021-08-12 18:26 ` Guillaume Nault
2021-08-12 19:04 ` Pali Rohár
2021-08-16 16:11 ` Guillaume Nault
2021-08-16 16:23 ` Pali Rohár
2021-08-17 16:05 ` Guillaume Nault
2021-08-17 16:21 ` Pali Rohár
2022-07-09 12:09 ` Pali Rohár
2022-07-12 17:34 ` Guillaume Nault
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