netmap custom RSS and custom packet info

Slawa Olhovchenkov slw at
Mon Jun 29 15:17:59 UTC 2015

Working with netmap and modern hardware I am lacking some features:

a) some spare space before packet (64/128/192/256 bytes) for
application data. For example: application do some pre-analysig
packet, filled structure in this space and routed packet (via NETMAP
pipe) to other thread. Received thread got packet and linked
inforamtion about this packet for processing w/o additional overhead.

b) custom RSS. Modern NIC have RSS poorly interoperable with packet
analysing: packets from same flow, but different direction placed in
different queue, PPPoE encapsulated packets placed in queue 0,
different tunneling don't recognised and etc. May be NETMAP can be
used custom RSS hashing from loadable kernel module, provideng by
user? Function frm this module can be packet analysing, tunnel
removing, custom RSS hashnig with direction-independly maner, filled
some structure prepended to buffer (see above) and pass this
information to application.

This is possible? This is useful not only to me?

More information about the freebsd-net mailing list