From: Stephen Hemminger <stephen@networkplumber.org>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
Cc: "Morten Brørup" <mb@smartsharesystems.com>,
dpdk-dev <dev@dpdk.org>, "Jerin Jacob" <jerinj@marvell.com>
Subject: Re: [dpdk-dev] packet data access bug in bpf and pdump libs
Date: Wed, 9 Oct 2019 08:02:18 -0700 [thread overview]
Message-ID: <20191009080218.3711bef3@hermes.lan> (raw)
In-Reply-To: <2601191342CEEE43887BDE71AB977258019197431F@irsmsx105.ger.corp.intel.com>
On Wed, 9 Oct 2019 11:11:46 +0000
"Ananyev, Konstantin" <konstantin.ananyev@intel.com> wrote:
> Hi Morten,
>
> >
> > Hi Konstantin and Stephen,
> >
> > I just noticed the same bug in your bpf and pcap libraries:
> >
> > You are using rte_pktmbuf_mtod(), but should be using rte_pktmbuf_read(). Otherwise you cannot read data across multiple segments.
>
> In plain data buffer mode expected input for BPF program is start of first segment packet data.
> Other segments are simply not available to BPF program in that mode.
> AFAIK, cBPF uses the same model.
>
> >
> >
> > Med venlig hilsen / kind regards
> > - Morten Brørup
>
For packet capture, the BPF program is only allowed to look at first segment.
pktmbuf_read is expensive and can cause a copy.
next prev parent reply other threads:[~2019-10-09 15:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 11:03 Morten Brørup
2019-10-09 11:11 ` Ananyev, Konstantin
2019-10-09 11:35 ` Morten Brørup
2019-10-09 15:02 ` Stephen Hemminger [this message]
2019-10-09 15:06 ` Morten Brørup
2019-10-09 15:14 ` Stephen Hemminger
2019-10-09 15:20 ` Morten Brørup
2019-10-09 17:24 ` Stephen Hemminger
2019-10-10 7:29 ` Morten Brørup
2019-10-10 15:36 ` Ananyev, Konstantin
2019-10-11 8:01 ` Morten Brørup
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