[PATCH v4 0/3] wireshark capture implementation

[Stephen Hemminger <stephen@networkplumber.org>]

This series adds live packet capture from a running DPDK application over the
telemetry socket. A new capture library installs Rx/Tx callbacks on an ethdev
port and writes pcapng to a FIFO, with an optional libpcap filter and
per-queue selection. A helper program presents those ports to Wireshark as
capture interfaces.

Advantages of this:
 - no secondary process needed to capture
 - installation is just putting the helper in the Wireshark extcap directory
 - the helper has no dependency on DPDK libraries; can be packaged with
   Wireshark
 - allows for live capture
 - supports BPF (with JIT) for filtering

How it works:
 - The capture library registers telemetry commands (/ethdev/capture/*)
 - Callbacks are installed on the specified port/queues to copy packets
 - Packets are formatted as pcapng and written to the specified output
 - No packet data passes through the telemetry socket itself

Packets handled by a secondary process are captured too, using EAL IPC as
pdump does.

The helper is a C program so that it can be installed with privilege, which
is what lets Wireshark capture from a root application without itself running
as root. See doc/guides/tools/wireshark_extcap.rst.

Linux and FreeBSD only. Windows needs the transport first: telemetry has no
socket server there and uses SOCK_SEQPACKET, which Windows AF_UNIX lacks.
A stream socket would need the replies framed.

Testing:
  - dpdk-wireshark-extcap --extcap-interfaces lists the ports. Reasons for an
    empty list go to stderr, which the Wireshark GUI hides.
  - Unit tests are in app/test/test_capture.c
  - Tested on Linux capturing from a root application as a non-root user.
    The unit test also passes on FreeBSD.

v4
 - helper rewritten in C, and can be installed with privilege so Wireshark
   need not run as the same user as the DPDK application
 - capture packets handled by secondary processes
 - split the library into several files by area
 - dropped the pcapng change adding the filter-accepted count to the
   interface statistics block. Still reported through telemetry.

v3 - fixed AI review feedback

Stephen Hemminger (3):
  capture: infrastructure wireshark packet capture
  test: add test for capture hooks
  usertools: add script for wireshark capture

 MAINTAINERS                            |    4 +
 app/test/meson.build                   |    1 +
 app/test/test_capture.c                |  688 ++++++++++++++
 doc/guides/prog_guide/capture_lib.rst  |  167 ++++
 doc/guides/prog_guide/index.rst        |    1 +
 doc/guides/rel_notes/release_26_11.rst |    5 +
 doc/guides/tools/index.rst             |    1 +
 doc/guides/tools/wireshark_extcap.rst  |  198 ++++
 lib/capture/capture.c                  |  560 ++++++++++++
 lib/capture/datapath.c                 |  420 +++++++++
 lib/capture/filter.c                   |  180 ++++
 lib/capture/meson.build                |   24 +
 lib/capture/multiproc.c                |  246 +++++
 lib/capture/output.c                   |  294 ++++++
 lib/capture/private.h                  |  214 +++++
 lib/meson.build                        |    1 +
 usertools/dpdk-wireshark-extcap.c      | 1145 ++++++++++++++++++++++++
 usertools/meson.build                  |   23 +
 18 files changed, 4172 insertions(+)
 create mode 100644 app/test/test_capture.c
 create mode 100644 doc/guides/prog_guide/capture_lib.rst
 create mode 100644 doc/guides/tools/wireshark_extcap.rst
 create mode 100644 lib/capture/capture.c
 create mode 100644 lib/capture/datapath.c
 create mode 100644 lib/capture/filter.c
 create mode 100644 lib/capture/meson.build
 create mode 100644 lib/capture/multiproc.c
 create mode 100644 lib/capture/output.c
 create mode 100644 lib/capture/private.h
 create mode 100644 usertools/dpdk-wireshark-extcap.c

-- 
2.53.0