from the FreeBSD network code. The flag is still kept around in the
"sys/mbuf.h" header file, but does no longer have any users. Instead
the "m_pkthdr.rsstype" field in the mbuf structure is now used to
decide the meaning of the "m_pkthdr.flowid" field. To modify the
"m_pkthdr.rsstype" field please use the existing "M_HASHTYPE_XXX"
macros as defined in the "sys/mbuf.h" header file.
This patch introduces new behaviour in the transmit direction.
Previously network drivers checked if "M_FLOWID" was set in "m_flags"
before using the "m_pkthdr.flowid" field. This check has now now been
replaced by checking if "M_HASHTYPE_GET(m)" is different from
"M_HASHTYPE_NONE". In the future more hashtypes will be added, for
example hashtypes for hardware dedicated flows.
"M_HASHTYPE_OPAQUE" indicates that the "m_pkthdr.flowid" value is
valid and has no particular type. This change removes the need for an
"if" statement in TCP transmit code checking for the presence of a
valid flowid value. The "if" statement mentioned above is now a direct
variable assignment which is then later checked by the respective
network drivers like before.
Additional notes:
- The SCTP code changes will be committed as a separate patch.
- Removal of the "M_FLOWID" flag will also be done separately.
- The FreeBSD version has been bumped.
MFC after: 1 month
Sponsored by: Mellanox Technologies
vxlan creates a virtual LAN by encapsulating the inner Ethernet frame in
a UDP packet. This implementation is based on RFC7348.
Currently, the IPv6 support is not fully compliant with the specification:
we should be able to receive UPDv6 packets with a zero checksum, but we
need to support RFC6935 first. Patches for this should come soon.
Encapsulation protocols such as vxlan emphasize the need for the FreeBSD
network stack to support batching, GRO, and GSO. Each frame has to make
two trips through the network stack, and each frame will be at most MTU
sized. Performance suffers accordingly.
Some latest generation NICs have begun to support vxlan HW offloads that
we should also take advantage of. VIMAGE support should also be added soon.
Differential Revision: https://reviews.freebsd.org/D384
Reviewed by: gnn
Relnotes: yes
