From: Stephen Hemminger <stephen@networkplumber.org>
To: dev@dpdk.org
Cc: Stephen Hemminger <stephen@networkplumber.org>
Subject: [RFC v2 00/12] Packet capture using port mirroring
Date: Wed, 9 Jul 2025 10:33:26 -0700 [thread overview]
Message-ID: <20250709173611.6390-1-stephen@networkplumber.org> (raw)
In-Reply-To: <0250411234927.114568-1-stephen@networkplumber.org>
This is a rework of how packet capture is done in DPDK.
The existing mechanism using callbacks has a number of problems:
it won't work when packets are sent and received in secondary process because
callbacks only function in the primary process; pdump requires that the
main program "opt-in" to having packet capture which requires changes
to existing network appliances.
The new mechanism builds on the concept of port mirroring used
in Linux/FreeBSD and also router vendors (SPAN ports).
See: https://en.wikipedia.org/wiki/Port_mirroring for a general description.
The implementation uses two new ethdev API's one to add
a port mirror, and one to remove it.
The internals of dumpcap are redone but the program command
syntax is unchanged (no doc change needed). Using the new mirror mechanism,
the dumpcap program creates a port using ring PMD and
then directs a port mirror to that new ring PMD instance.
Then the packets are extracted from the ring.
If capturing on multiple devices, they all get mirrored to
the same ring PMD.
The dumpcap program needs to be able to start the ring PMD it created
but the existing ethdev API is broken when used from secondary process.
One of the patches fixes that, it was also reported previously in Bugzilla.
The mirror API has a restriction that the port being mirrored to must allow
lock free transmit. This is because both Rx and Tx as well as multiple
queues need to go over the same transmit queue. Although it might be possible
to have some complex mapping between multiple ports/queues being mirrored
to multiple transmit queues, that gets to be a lot of overhead in API's
and implementation. Fixing the ring and null PMD to allow lockless
transmit is good enough.
Added tests for the new features.
The performance has not been measured but the overhead of checking for
mirror port is no more that the overhead of looking at the callback list.
TODO items:
- some names are too verbose
- need release notes for new features
- more through testing on real hardware
Stephen Hemminger (12):
ethdev: allow start/stop from secondary process
test: add test for hotplug and secondary process operations
net/ring: allow lockfree transmit if ring supports it
net/ring: add new devargs for dumpcap use
mbuf: add dynamic flag for use by port mirroring
ethdev: add port mirroring feature
pcapng: split packet copy from header insertion
pcapng: make queue optional
test: add tests for ethdev mirror
app/testpmd: support for port mirroring
app/dumpcap: use port mirror instead of pdump
pdump: mark API and application as deprecated
app/dumpcap/main.c | 443 ++++++++++++++++----
app/dumpcap/meson.build | 2 +-
app/pdump/main.c | 3 +
app/pdump/meson.build | 1 +
app/test-pmd/cmdline.c | 1 +
app/test-pmd/cmdline_mirror.c | 129 ++++++
app/test-pmd/cmdline_mirror.h | 12 +
app/test-pmd/meson.build | 2 +
app/test/meson.build | 7 +-
app/test/test_ethdev_mirror.c | 285 +++++++++++++
app/test/test_mp_secondary.c | 51 ++-
config/rte_config.h | 1 +
doc/guides/rel_notes/deprecation.rst | 3 +
doc/guides/testpmd_app_ug/testpmd_funcs.rst | 15 +
drivers/net/ring/rte_eth_ring.c | 91 +++-
lib/ethdev/ethdev_driver.c | 11 +-
lib/ethdev/ethdev_driver.h | 6 +
lib/ethdev/ethdev_private.c | 133 ++++++
lib/ethdev/ethdev_private.h | 29 ++
lib/ethdev/ethdev_trace.h | 17 +
lib/ethdev/ethdev_trace_points.c | 6 +
lib/ethdev/meson.build | 1 +
lib/ethdev/rte_ethdev.c | 101 +++--
lib/ethdev/rte_ethdev.h | 23 +-
lib/ethdev/rte_ethdev_core.h | 6 +-
lib/ethdev/rte_mirror.c | 344 +++++++++++++++
lib/ethdev/rte_mirror.h | 113 +++++
lib/mbuf/rte_mbuf_dyn.h | 9 +
lib/pcapng/rte_pcapng.c | 179 ++++----
lib/pcapng/rte_pcapng.h | 27 +-
lib/pdump/rte_pdump.h | 12 +-
31 files changed, 1851 insertions(+), 212 deletions(-)
create mode 100644 app/test-pmd/cmdline_mirror.c
create mode 100644 app/test-pmd/cmdline_mirror.h
create mode 100644 app/test/test_ethdev_mirror.c
create mode 100644 lib/ethdev/rte_mirror.c
create mode 100644 lib/ethdev/rte_mirror.h
--
2.47.2
next parent reply other threads:[~2025-07-09 17:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <0250411234927.114568-1-stephen@networkplumber.org>
2025-07-09 17:33 ` Stephen Hemminger [this message]
2025-07-09 17:33 ` [RFC v2 01/12] ethdev: allow start/stop from secondary process Stephen Hemminger
2025-07-09 17:47 ` Khadem Ullah
2025-07-09 17:33 ` [RFC v2 02/12] test: add test for hotplug and secondary process operations Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 03/12] net/ring: allow lockfree transmit if ring supports it Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 04/12] net/ring: add new devargs for dumpcap use Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 05/12] mbuf: add dynamic flag for use by port mirroring Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 06/12] ethdev: add port mirroring feature Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 07/12] pcapng: split packet copy from header insertion Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 08/12] pcapng: make queue optional Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 09/12] test: add tests for ethdev mirror Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 10/12] app/testpmd: support for port mirroring Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 11/12] app/dumpcap: use port mirror instead of pdump Stephen Hemminger
2025-07-09 17:33 ` [RFC v2 12/12] pdump: mark API and application as deprecated Stephen Hemminger
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