From: Stephen Hemminger <stephen@networkplumber.org>
To: "Morten Brørup" <mb@smartsharesystems.com>
Cc: "Konstantin Ananyev" <konstantin.ananyev@huawei.com>, <dev@dpdk.org>
Subject: Re: [DPDK/ethdev Bug 1416] net/af_packet: tx_burst() can modify packets
Date: Tue, 16 Apr 2024 13:09:10 -0700 [thread overview]
Message-ID: <20240416130910.22d1013f@hermes.local> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35E9F3AA@smartserver.smartshare.dk>
On Tue, 16 Apr 2024 20:11:05 +0200
Morten Brørup <mb@smartsharesystems.com> wrote:
> > > > > > static uint16_t
> > > > > > eth_af_packet_tx(void *queue, struct rte_mbuf **bufs, uint16_t
> > > > nb_pkts)
> > > > > > {
> > > > > > ...
> > > > > > for (i = 0; i < nb_pkts; i++) {
> > > > > > mbuf = *bufs++;
> > > > > >
> > > > > > ...
> > > > > >
> > > > > > /* insert vlan info if necessary */
> > > > > > if (mbuf->ol_flags & RTE_MBUF_F_TX_VLAN) {
> > > > > > if (rte_vlan_insert(&mbuf)) {
> > > > > > rte_pktmbuf_free(mbuf);
> > > > > > continue;
> > > > > >
> > > > > > AFAIU, it does copy of mbuf contents into pbuf anyway (just few
> > line
> > > > below).
> > > > > > So the fix might be - simply insert VLAN tag at copying stage.
> > > > > > Feel free to correct me, if I missed something.
> > > > >
> > > > > vlan_insert will fail if the mbuf is has refcnt > 1.
> > > > >
> > > > > static inline int rte_vlan_insert(struct rte_mbuf **m)
> > > > > {
> > > > > struct rte_ether_hdr *oh, *nh;
> > > > > struct rte_vlan_hdr *vh;
> > > > >
> > > > > /* Can't insert header if mbuf is shared */
> > > > > if (!RTE_MBUF_DIRECT(*m) || rte_mbuf_refcnt_read(*m) > 1)
> > > > > return -EINVAL;
> > > >
> > > > You are right, I missed that.
> > > > Will close it then.
> > >
> > > Don't close, silent drop is also a bug.
> > >
> > > The VLAN tag could be insert when copying, as originally suggested.
> >
> > Agree, but to me that would be enhancement request, not a bug report.
>
> Hmm... there is still a bug, although slightly different:
>
> net/af_packet: tx_burst() silently drops packets with RTE_MBUF_F_TX_VLAN if mbuf is shared
>
> And the suggested fixes would fix this (other) bug.
In older DPDK, vlan_insert would try and clone the mbuf, but doing a rte_pktmbuf_clone().
But that was buggy and removed by:
commit 15a74163b12ed9b8b980b1576bdd8de16d60612b
Author: Ferruh Yigit <ferruh.yigit@intel.com>
Date: Tue Apr 16 16:51:26 2019 +0100
net: forbid VLAN insert in shared mbuf
The vlan_insert() is buggy when it tries to handle the shared mbufs,
instead don't support inserting VLAN tag into shared mbufs and return
an error for that case.
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
next prev parent reply other threads:[~2024-04-16 20:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-16 10:29 [DPDK/ethdev Bug 1416] net/af_packet: tx_burst() can modify packets bugzilla
2024-04-16 15:38 ` Stephen Hemminger
2024-04-16 15:56 ` Konstantin Ananyev
2024-04-16 16:14 ` Morten Brørup
2024-04-16 16:42 ` Konstantin Ananyev
2024-04-16 18:11 ` Morten Brørup
2024-04-16 20:09 ` Stephen Hemminger [this message]
2024-04-16 22:21 ` Morten Brørup
2024-04-16 15:58 ` bugzilla
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=20240416130910.22d1013f@hermes.local \
--to=stephen@networkplumber.org \
--cc=dev@dpdk.org \
--cc=konstantin.ananyev@huawei.com \
--cc=mb@smartsharesystems.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.