epair: add support for checksum offloadingHEADmain

Add capabilities RXCSUM and RXCSUM6 as well as TXCSUM and TXCSUM6 for
for receive and transmit checksum offloading for TCP and UDP to the
epair interface and enable them by default.
RXCSUM and RXCSUM6 are enabled because an epair interface may receive
a packet with the csum_flag CSUM_DATA_VALID set, which is expected
only if these capabilities are enabled. Since it seems not helpful to
remove this flag, it is not possible to disable these capabilities.
TXCSUM and TXCSUM6 are synchronized between the two epair interface
ends. If enabled/disabled on one end, it will be enabled/disabled on
the other end. If the sending epair interface end has TXCSUM or TXCSUM6
enabled and the receiving end is in a bridge, it is assumed that all
interfaces in the bridge have that capability enabled. Otherwise the
bridge would have disabled that capability on the receiving epair
interface end in the bridge which would have disabled that capability
on the sending epair interface end as well due to the synchronization.

This change was committed and reverted earlier, since several pf
tests were failing. This has been addressed.

Reviewed by:		bcr, Seyed Pouria Mousavizadeh Tehrani, tuexen
MFC after:		4 weeks
Differential Revision:	https://reviews.freebsd.org/D51639

0 files changed, 0 insertions, 0 deletions