net: add ioctls for the RSS key and indirection table

[nprice]

Summary

Nothing can set the RSS key, and the indirection table is visible only
through driver-private sysctls.

RSS_TABLELEN is 2048 for ice's 2K lookup table. The ioctl number
encodes the structure size, so it cannot grow, and a larger table is
refused with EMSGSIZE.

A set does not update the stack's key or rss_table[], so under options
RSS the software hash stops predicting that device's queue.

Signed-off-by: Nick Price <[e-mail]>

[nick_spun.io]

This comment was removed by nick_spun.io.

[nick_spun.io]

sys/net/if.h

657

ice(4) can report a RSS_TABLELEN with 2048 entries - not sure whether we should keep making the ioctl larger or do something else

[nick_spun.io]

rebase on main and remove redundant ioctls already added by kbowling