sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

Define a module version for accept filter modules.

Otherwise accept filters compiled into the kernel do not preempt
preloaded accept filter modules. Then, the preloaded file registers its
accept filter module before the kernel, and the kernel's attempt fails
since duplicate accept filter list entries are not permitted. This
causes the preloaded file's module to be released, since
module_register_init() does a lookup by name, so the preloaded file is
unloaded, and the accept filter's callback points to random memory since
preload_delete_name() unmaps the file on x86 as of r336505.

Add a new ACCEPT_FILTER_DEFINE macro which wraps the accept filter and
module definitions, and ensures that a module version is defined.

PR: 245870
Reported by: Thomas von Dein <freebsd@daemon.de>
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

sys: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Rework socket upcalls to close some races with setup/teardown of upcalls.
- Each socket upcall is now invoked with the appropriate socket buffer
locked. It is not permissible to call soisconnected() with this lock
held; however, so socket upcalls now return an integer value. The two
possible values are SU_OK and SU_ISCONNECTED. If an upcall returns
SU_ISCONNECTED, then the soisconnected() will be invoked on the
socket after the socket buffer lock is dropped.
- A new API is provided for setting and clearing socket upcalls. The
API consists of soupcall_set() and soupcall_clear().
- To simplify locking, each socket buffer now has a separate upcall.
- When a socket upcall returns SU_ISCONNECTED, the upcall is cleared from
the receive socket buffer automatically. Note that a SO_SND upcall
should never return SU_ISCONNECTED.
- All this means that accept filters should now return SU_ISCONNECTED
instead of calling soisconnected() directly. They also no longer need
to explicitly clear the upcall on the new socket.
- The HTTP accept filter still uses soupcall_set() to manage its internal
state machine, but other accept filters no longer have any explicit
knowlege of socket upcall internals aside from their return value.
- The various RPC client upcalls currently drop the socket buffer lock
while invoking soreceive() as a temporary band-aid. The plan for
the future is to add a new flag to allow soreceive() to be called with
the socket buffer locked.
- The AIO callback for socket I/O is now also invoked with the socket
buffer locked. Previously sowakeup() would drop the socket buffer
lock only to call aio_swake() which immediately re-acquired the socket
buffer lock for the duration of the function call.

Discussed with: rwatson, rmacklem

- Import the HEAD csup code which is the basis for the cvsmode work.

Add FBSDID to all files in netinet so that people can more
easily include file version information in bug reports.

Approved by: re (kensmith)

add missing #include <sys/module.h>

Remove so*_locked(), which were backed out by mistake.

Back out my lats commit of locking down a socket, it conflicts with hsu's work.

Requested by: hsu

Lock down a socket, milestone 1.

o Add a mutex (sb_mtx) to struct sockbuf. This protects the data in a
socket buffer. The mutex in the receive buffer also protects the data
in struct socket.

o Determine the lock strategy for each members in struct socket.

o Lock down the following members:

- so_count
- so_options
- so_linger
- so_state

o Remove *_locked() socket APIs. Make the following socket APIs
touching the members above now require a locked socket:

- sodisconnect()
- soisconnected()
- soisconnecting()
- soisdisconnected()
- soisdisconnecting()
- sofree()
- soref()
- sorele()
- sorwakeup()
- sotryfree()
- sowakeup()
- sowwakeup()

Reviewed by: alfred

Redo the sigio locking.

Turn the sigio sx into a mutex.

Sigio lock is really only needed to protect interrupts from dereferencing
the sigio pointer in an object when the sigio itself is being destroyed.

In order to do this in the most unintrusive manner change pgsigio's
sigio * argument into a **, that way we can lock internally to the
function.

Revert the change of #includes in sys/filedesc.h and sys/socketvar.h.

Requested by: bde

Since locking sigio_lock is usually followed by calling pgsigio(),
move the declaration of sigio_lock and the definitions of SIGIO_*() to
sys/signalvar.h.

While I am here, sort include files alphabetically, where possible.

Add a global sx sigio_lock to protect the pointer to the sigio object
of a socket. This avoids lock order reversal caused by locking a
process in pgsigio().

sowakeup() and the callers of it (sowwakeup, soisconnected, etc.) now
require sigio_lock to be locked. Provide sowwakeup_locked(),
soisconnected_locked(), and so on in case where we have to modify a
socket and wake up a process atomically.

Remove headers not needed.

Pointed out by: phk

Forget to include sysctl.h

Submitted by: des

return of the accept filter part II

accept filters are now loadable as well as able to be compiled into
the kernel.

two accept filters are provided, one that returns sockets when data
arrives the other when an http request is completed (doesn't work
with 0.9 requests)

Reviewed by: jmg