[PATCH v11 00/19] net/pcap: improvements and test suite

Stephen Hemminger
2026-01-30T17:34:59Z

This series contains improvements to the PCAP PMD including new
features, bug fixes, code cleanup, and a comprehensive test suite.

New features:
- VLAN tag insertion on Tx and stripping on Rx
- Nanosecond precision timestamps (when hardware/libpcap supports it)
- Accurate link state, speed, and duplex reporting in interface mode
- Support for Windows interface mode
- Advertise RTE_ETH_TX_OFFLOAD_MULTI_SEGS capability
- Configurable snapshot length via snapshot_len devarg

Bug fixes:
- Fix multi-segment transmit to dynamically allocate instead of
silently truncating packets larger than 9K stack buffer
- Change Tx burst to always consume all packets; failed sends
increment error counter rather than leaving mbufs for retry
(pcap_sendpacket failures are not transient)
- Reject non-Ethernet interfaces to prevent malformed packets
and kernel warnings on FreeBSD/macOS loopback

Code cleanup:
- Convert internal flags from int to bool
- Remove unnecessary casts of void* from rte_zmalloc
- Replace rte_malloc/rte_memcpy with libc equivalents in osdep code
- Include headers explicitly rather than relying on indirect includes
- Remove unnecessary volatile qualifier on statistics
- Reduce scope of file-level variables
- Defer pcap handle opening until device start
- Use bulk free for better Tx performance

Testing:
- Add comprehensive unit test suite covering basic operations,
timestamps, jumbo frames, VLAN handling, multi-queue, and more
- Test discovers network interfaces using pcap_findalldevs API
for portable interface enumeration across Linux, FreeBSD, macOS,
and Windows

v11:
- Fix build on FreeBsd

v10:
- Split transmit handling into separate patches for bulk free,
bounce buffer allocation, and cleanup for easier review
- Add patch to reject non-Ethernet interfaces (fixes loopback
issues on FreeBSD/macOS where DLT_NULL is used)
- Test uses pcap_findalldevs() for portable interface discovery
instead of hardcoded interface names

v9:
- Add configurable snapshot length parameter (snapshot_len devarg)
- Defer opening of pcap files and interfaces until eth_dev_start()
instead of during probe, passing configured snapshot length

Stephen Hemminger (19):
maintainers: update for pcap driver
doc: update features for PCAP PMD
net/pcap: include used headers
net/pcap: remove unnecessary casts
net/pcap: avoid using rte_malloc and rte_memcpy
net/pcap: use bulk free
net/pcap: allocate Tx bounce buffer
net/pcap: cleanup transmit buffer handling
net/pcap: report multi-segment transmit capability
net/pcap: consolidate boolean flag handling
net/pcap: support VLAN insert and strip
net/pcap: add link state and speed for interface mode
net/pcap: support nanosecond timestamp precision
net/pcap: reject non-Ethernet interfaces
net/pcap: reduce scope of file-level variables
net/pcap: avoid use of volatile
net/pcap: clarify maximum received packet
net/pcap: add snapshot length devarg
test: add test for pcap PMD

MAINTAINERS | 1 +
app/test/meson.build | 2 +
app/test/test_pmd_pcap.c | 2622 ++++++++++++++++++++++++
doc/guides/nics/features/pcap.ini | 8 +
doc/guides/nics/pcap_ring.rst | 27 +
doc/guides/rel_notes/release_26_03.rst | 9 +
drivers/net/pcap/pcap_ethdev.c | 655 ++++--
drivers/net/pcap/pcap_osdep.h | 23 +
drivers/net/pcap/pcap_osdep_freebsd.c | 98 +-
drivers/net/pcap/pcap_osdep_linux.c | 115 +-
drivers/net/pcap/pcap_osdep_windows.c | 95 +-
11 files changed, 3417 insertions(+), 238 deletions(-)
create mode 100644 app/test/test_pmd_pcap.c

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2.51.0