Merge from head

IFC @ r255209

MFC

Restructure the mbuf pkthdr to make it fit for upcoming capabilities and
features. The changes in particular are:

o Remove rarely used "header" pointer and replace it with a 64bit protocol/
layer

Restructure the mbuf pkthdr to make it fit for upcoming capabilities and
features. The changes in particular are:

o Remove rarely used "header" pointer and replace it with a 64bit protocol/
layer specific union PH_loc for local use. Protocols can flexibly overlay
their own 8 to 64 bit fields to store information while the packet is
worked on.

o Mechanically convert IP reassembly, IGMP/MLD and ATM to use pkthdr.PH_loc
instead of pkthdr.header.

o Extend csum_flags to 64bits to allow for additional future offload
information to be carried (e.g. iSCSI, IPsec offload, and others).

o Move the RSS hash type enumerator from abusing m_flags to its own 8bit
rsstype field. Adjust accessor macros.

o Add cosqos field to store Class of Service / Quality of Service information
with the packet. It is not yet supported in any drivers but allows us to
get on par with Cisco/Juniper in routing applications (plus MPLS QoS) with
a modernized ALTQ.

o Add four 8 bit fields l[2-5]hlen to store the relative header offsets
from the start of the packet. This is important for various offload
capabilities and to relieve the drivers from having to parse the packet
and protocol headers to find out location of checksums and other
information. Header parsing in drivers is a lot of copy-paste and
unhandled corner cases which we want to avoid.

o Add another flexible 64bit union to map various additional persistent
packet information, like ether_vtag, tso_segsz and csum fields.
Depending on the csum_flags settings some fields may have different usage
making it very flexible and adaptable to future capabilities.

o Restructure the CSUM flags to better signify their outbound (down the
stack) and inbound (up the stack) use. The CSUM flags used to be a bit
chaotic and rather poorly documented leading to incorrect use in many
places. Bring clarity into their use through better naming.
Compatibility mappings are provided to preserve the API. The drivers
can be corrected one by one and MFC'd without issue.

o The size of pkthdr stays the same at 48/56bytes (32/64bit architectures).

Sponsored by: The FreeBSD Foundation

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Add m_clrprotoflags() to clear protocol specific mbuf flags at up and
downwards layer crossings.

Consistently use it within IP, IPv6 and ethernet protocols.

Discussed with: trociny, glebius

IFC @ r254014

IFC @253398

Merge fresh head.

Disable IGMPv3 link timers on a transition to IGMPv2.

Submitted by: Alan Smithee

sync from head

MFC @248461

- Replace compat macros with function calls.

We can, and should use M_WAITOK here.

Sponsored by: Nginx, Inc.

IFC @247348.

Sync with HEAD.

IFC @ r244983.

Mechanically substitute flags from historic mbuf allocator with
malloc(9) flags within sys.

Exceptions:

- sys/contrib not touched
- sys/mbuf.h edited manually

MFC

IFC @ r242684

Sync from head

Do not reduce ip_len by size of IP header in the ip_input()
before passing a packet to protocol input routines.
For several protocols this mean that now protocol needs to
do subtraction itself, and

Do not reduce ip_len by size of IP header in the ip_input()
before passing a packet to protocol input routines.
For several protocols this mean that now protocol needs to
do subtraction itself, and for another half this means that
we do not need to add header length back to the packet.

Make ip_stripoptions() to adjust ip_len, since now we enter
this function with a packet header whose ip_len does represent
length of entire packet, not payload only.

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Switch the entire IPv4 stack to keep the IP packet header
in network byte order. Any host byte order processing is
done in local variables and host byte order values are
never[1] written to a packet.

Switch the entire IPv4 stack to keep the IP packet header
in network byte order. Any host byte order processing is
done in local variables and host byte order values are
never[1] written to a packet.

After this change a packet processed by the stack isn't
modified at all[2] except for TTL.

After this change a network stack hacker doesn't need to
scratch his head trying to figure out what is the byte order
at the given place in the stack.

[1] One exception still remains. The raw sockets convert host
byte order before pass a packet to an application. Probably
this would remain for ages for compatibility.

[2] The ip_input() still subtructs header len from ip->ip_len,
but this is planned to be fixed soon.

Reviewed by: luigi, Maxim Dounin <mdounin mdounin.ru>
Tested by: ray, Olivier Cochard-Labbe <olivier cochard.me>

show more ...

Revert previous commit...

Pointyhat to: kevlo (myself)

Prefer NULL over 0 for pointers

Merge head r236710 through r238467.