Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merge r261582, r261601, r261610, r261613, r261627, r261640, r261641, r261823,
r261825, r261859, r261875, r261883, r261911, r262027, r262028, r262029,
r262030, r262162 from head.

Large flowtable revamp. See commit messages for merged revisions for
details.

Sponsored by: Netflix

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

allocate ipv6 flows from the ipv6 flow zone

reported by: rrs@

MFC after: 3 days

- restructure flowtable to support ipv6
- add a name argument to flowtable_alloc for printing with ddb commands
- extend ddb commands to print destination address or 4-tuples
- don't parse ports in ulp header if FL_HASH_ALL is not passed
- add kern_flowtable_insert to enable more generic use of flowtable
(e.g. system calls for adding entries)
- don't hash loopback addresses
- cleanup whitespace
- keep statistics per-cpu for per-cpu flowtables to avoid cache line contention
- add sysctls to accumulate stats and report aggregate

MFC after: 7 days

The flow-table associates TCP/UDP flows and IP destinations with
specific routes. When the routing table changes, for example,
when a new route with a more specific prefix is inserted into the
routing table, the flow-table is not updated to reflect that change.
As such existing connections cannot take advantage of the new path.
In some cases the path is broken. This patch will update the affected
flow-table entries when a more specific route is added. The route
entry is properly marked when a route is deleted from the table.
In this case, when the flow-table performs a search, the stale
entry is updated automatically. Therefore this patch is not
necessary for route deletion.

Submitted by: simon, phk
Reviewed by: bz, kmacy
MFC after: 3 days

- change the interface to flowtable_lookup so that we don't rely on
the mbuf for obtaining the fib index
- check that a cached flow corresponds to the same fib index as the
packet for which we are doing the lookup
- at interface detach time flush any flows referencing stale rtentrys
associated with the interface that is going away (fixes reported
panics)
- reduce the time between cleans in case the cleaner is running at
the time the eventhandler is called and the wakeup is missed less
time will elapse before the eventhandler returns
- separate per-vnet initialization from global initialization
(pointed out by jeli@)

Reviewed by: sam@
Approved by: re@

Remove unused VNET_SET() and related macros; only VNET_GET() is
ever actually used. Rename VNET_GET() to VNET() to shorten
variable references.

Discussed with: bz, julian
Reviewed by: bz
Approved by: re (kensmith, kib)

Build on Jeff Roberson's linker-set based dynamic per-CPU allocator
(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator. Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...). This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack. Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory. Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy. Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address. When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by: bz
Reviewed by: bz, zec
Discussed with: gnn, jamie, jeff, jhb, julian, sam
Suggested by: peter
Approved by: re (kensmith)

V_irtualize flowtable state.

This change should make options VIMAGE kernel builds usable again,
to some extent at least.

Note that the size of struct vnet_inet has changed, though in
accordance with one-bump-per-day policy we didn't update the
__FreeBSD_version number, given that it has already been touched
by r194640 a few hours ago.
Reviewed by: bz
Approved by: julian (mentor)

Garbage collect an extern for a non-existent variable.
While here let the comment end in a '.' and mark the #endif of _KERNEL.

Reviewed by: rwatson (as part of a larger patch)

Move the kernel option FLOWTABLE chacking from the header file to the
actual implementation.
Remove the accessor functions for the compiled out case, just returning
"unavail" values. Remove the kernel conditional from the header file as
it is no longer needed, only leaving the externs.
Hide the improperly virtualized SYSCTL/TUNABLE for the flowtable size
under the kernel option as well.

Reviewed by: rwatson

revert to opt-in flowtable

make flowtable opt-out

Remove two unneeded, hidden includes.

After r193232 rt_tables in vnet.h are no longer indirectly dependent on
the ROUTETABLES kernel option thus there is no need to include opt_route.h
anymore in all consumers of vnet.h and no longer depend on it for module
builds.

Remove the hidden include in flowtable.h as well and leave the two
explicit #includes in ip_input.c and ip_output.c.

- Import infrastructure for caching flows as a means of accelerating L3 and L2 lookups
as well as providing stateful load balancing when used with RADIX_MPATH.
- Currently compiled in to i386 and amd64 but disabled by default, it can be enabled at
runtime with 'sysctl net.inet.flowtable.enable=1'.

- Embedded users can remove it entirely from the kernel by adding 'nooption FLOWTABLE' to
their kernel config files.

- A minimal hookup will be added to ip_output in a subsequent commit. I would like to see
more review before bringing in changes that require more churn.

Supported by: Bitgravity Inc.