Re: [PATCH net-next v4 2/6] net: dcb: add new apptrust attribute

From: Petr Machata <petrm@nvidia.com>
To: <Daniel.Machon@microchip.com>
Cc: <petrm@nvidia.com>, <netdev@vger.kernel.org>,
	<davem@davemloft.net>, <maxime.chevallier@bootlin.com>,
	<thomas.petazzoni@bootlin.com>, <edumazet@google.com>,
	<kuba@kernel.org>, <pabeni@redhat.com>,
	<Lars.Povlsen@microchip.com>, <Steen.Hegelund@microchip.com>,
	<UNGLinuxDriver@microchip.com>, <joe@perches.com>,
	<linux@armlinux.org.uk>, <Horatiu.Vultur@microchip.com>,
	<Julia.Lawall@inria.fr>, <vladimir.oltean@nxp.com>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH net-next v4 2/6] net: dcb: add new apptrust attribute
Date: Mon, 31 Oct 2022 17:24:32 +0100	[thread overview]
Message-ID: <87pme8ufjg.fsf@nvidia.com> (raw)
In-Reply-To: <Y1/F5n+geZHAitoW@DEN-LT-70577>

<Daniel.Machon@microchip.com> writes:

>> > +     if (ieee[DCB_ATTR_DCB_APP_TRUST_TABLE]) {
>> > +             u8 selectors[IEEE_8021QAZ_APP_SEL_MAX + 1] = {0};
>> > +             struct nlattr *attr;
>> > +             int nselectors = 0;
>> > +             u8 selector;
>> > +             int rem, i;
>> > +
>> > +             if (!ops->dcbnl_setapptrust) {
>> > +                     err = -EOPNOTSUPP;
>> > +                     goto err;
>> > +             }
>> > +
>> > +             nla_for_each_nested(attr, ieee[DCB_ATTR_DCB_APP_TRUST_TABLE],
>> > +                                 rem) {
>> > +                     if (nla_type(attr) != DCB_ATTR_DCB_APP_TRUST ||
>> > +                         nla_len(attr) != 1 ||
>> > +                         nselectors >= sizeof(selectors)) {
>> > +                             err = -EINVAL;
>> > +                             goto err;
>> > +                     }
>> > +
>> > +                     selector = nla_get_u8(attr);
>> > +                     switch (selector) {
>> > +                     case IEEE_8021QAZ_APP_SEL_ETHERTYPE:
>> > +                     case IEEE_8021QAZ_APP_SEL_STREAM:
>> > +                     case IEEE_8021QAZ_APP_SEL_DGRAM:
>> > +                     case IEEE_8021QAZ_APP_SEL_ANY:
>> > +                     case IEEE_8021QAZ_APP_SEL_DSCP:
>> > +                     case DCB_APP_SEL_PCP:
>> 
>> This assumes that the range of DCB attributes will never overlap with
>> the range of IEEE attributes. Wasn't the original reason for introducing
>> the DCB nest to not have to make this assumption?
>> 
>> I.e. now that we split DCB and IEEE attributes in the APP_TABLE
>> attribute, shouldn't it be done here as well?
>
> Hmm, doesn't hurt to do strict checking here as well. We can even get rid
> of the DCB_ATTR_DCB_APP_TRUST attr and just pass DCB_ATTR_DCB_APP and
> DCB_ATTR_IEEE_APP? Then use the same functions to do the checking.

That would make sense to me.

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