sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

dummynet: use m_rcvif_serialize/restore when queueing packets

This fixed panic with interface being removed while packet
was sitting on a queue. This allows to pass all dummynet
tests including forthcoming dummynet:ipfw_interface_removal
and dummynet:pf_interface_removal and demonstrates use of
m_rcvif_serialize() and m_rcvif_restore().

Reviewed by: kp
Differential revision: https://reviews.freebsd.org/D33267

(cherry picked from commit 165746f4e4bf54c5902a103c2d4a3455e651c58f)

Revert "dummynet: use m_rcvif_serialize/restore when queueing packets"

This reverts commit 165746f4e4bf54c5902a103c2d4a3455e651c58f.

Obtained from: github.com/glebius/FreeBSD/commits/backout-ifindex

netpfil: Fix two typo in source code comments

- s/measurment/measurement/

While here, also fix some whitespace issues.

MFC after: 3 days

dummynet: don't use per-vnet locks to protect global data.

The ref_count counter is global (i.e. not per-vnet) so we can't use a
per-vnet lock to protect it. Moreover, in callouts curvnet is not set,
so we'd end up panicing when trying to use DN_BH_WLOCK().

Instead we use the global sched_lock, which is already used when
evaluating ref_count (in unload_dn_aqm()).

Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D34059

dummynet: use m_rcvif_serialize/restore when queueing packets

This fixed panic with interface being removed while packet
was sitting on a queue. This allows to pass all dummynet
tests including forthcoming dummynet:ipfw_interface_removal
and dummynet:pf_interface_removal and demonstrates use of
m_rcvif_serialize() and m_rcvif_restore().

Reviewed by: kp
Differential revision: https://reviews.freebsd.org/D33267

dummynet: drop unused definitions

Reviewed by: kp
Differential Revision: https://reviews.freebsd.org/D33429

VNETify dummynet

This moves dn_cfg and other parameters into per VNET variables.

The taskqueue and control state remains global.

Reviewed by: kp
Differential Revision: https://reviews.freebsd.org/D29274

dummynet: Fix mbuf tag allocation failure handling

PR: 255875, 255878, 255879, 255880
Reviewed by: donner, kp
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30318

net: clean up empty lines in .c and .h files

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.

This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT

Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718

Fix the queue delay estimation in PIE/FQ-PIE when the timestamp
(TS) method is used. When packet timestamp is used, the "current_qdelay"
keeps storing the last queue delay value calculated in the dequeue
function. Therefore, when a burst of packets arrives followed by
a pause, the "current_qdelay" will store a high value caused by the
burst and stick to that value during the pause because the queue
delay measurement is done inside the dequeue function. This causes
the drop probability calculation function to calculate high drop
probability value instead of zero and prevents the burst allowance
mechanism from working properly. Fix this problem by resetting
"current_qdelay" inside the drop probability calculation function
when the queue length is zero and TS option is used.

Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au>
MFC after: 1 week

The result of right shifting a negative signed value is implementation
defined. On machines without arithmetic shift instructions, zero bits
may be shifted in from the left, giving a large positive result instead
of the desired divide-by power-of-2. Fix this by operating on the
absolute value and compensating for the possible negation later.

Reverse the order of the underflow/overflow tests and the exponential
decay calculation to avoid the possibility of an erroneous overflow
detection if p is a sufficiently small non-negative value. Also
check for negative values of prob before doing the exponential decay
to avoid another instance of of right shifting a negative value.

Tested by: Rasool Al-Saadi <ralsaadi@swin.edu.au>
MFC after: 1 week

dummynet: Use strlcpy to appease static checkers

Some dummynet modules used strcpy() to copy from a larger buffer
(dn_aqm->name) to a smaller buffer (dn_extra_parms->name). It happens that
the lengths of the strings in the dn_aqm buffers were always hardcoded to be
smaller than the dn_extra_parms buffer ("CODEL", "PIE").

Use strlcpy() instead, to appease static checkers. No functional change.

Reported by: Coverity
CIDs: 1356163, 1356165
Sponsored by: Dell EMC Isilon

Fix a race condition between the main thread in aqm_pie_cleanup() and the
callout thread that can cause a kernel panic. Always do the final cleanup
in the callout thread by passing a separate callout function for that task
to callout_reset_sbt().

Protect the ref_count decrement in the callout with DN_BH_WLOCK(). All
other ref_count manipulation is protected with this lock.

There is still a tiny window between ref_count reaching zero and the end
of the callout function where it is unsafe to unload the module. Fixing
this would require the use of callout_drain(), but this can't be done
because dummynet holds a mutex and callout_drain() might sleep.

Remove the callout_pending(), callout_active(), and callout_deactivate()
calls from calculate_drop_prob(). They are not needed because this callout
uses callout_init_mtx().

Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au>
Approved by: re (gjb)
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D6928

Replace constant expressions that contain multiplications by
fractional floating point values with integer divides. This will
eliminate any chance that the compiler will generate code to evaluate
the expression using floating point at runtime.

Suggested by: bde
Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au>
MFC after: 8 days (with r300779 and r300949)

Cast some expressions that multiply a long long constant by a
floating point constant to int64_t. This avoids the runtime
conversion of the the other operand in a set of comparisons from
int64_t to floating point and doing the comparisions in floating
point.

Suggested by: lidl
Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au>
MFC after: 2 weeks (with r300779)

Import Dummynet AQM version 0.2.1 (CoDel, FQ-CoDel, PIE and FQ-PIE).

Centre for Advanced Internet Architectures

Implementing AQM in FreeBSD

* Overview <http://caia.swin.edu.au/freebsd/aqm/index.html>

* Articles, Papers and Presentations
<http://caia.swin.edu.au/freebsd/aqm/papers.html>

* Patches and Tools <http://caia.swin.edu.au/freebsd/aqm/downloads.html>

Overview

Recent years have seen a resurgence of interest in better managing
the depth of bottleneck queues in routers, switches and other places
that get congested. Solutions include transport protocol enhancements
at the end-hosts (such as delay-based or hybrid congestion control
schemes) and active queue management (AQM) schemes applied within
bottleneck queues.

The notion of AQM has been around since at least the late 1990s
(e.g. RFC 2309). In recent years the proliferation of oversized
buffers in all sorts of network devices (aka bufferbloat) has
stimulated keen community interest in four new AQM schemes -- CoDel,
FQ-CoDel, PIE and FQ-PIE.

The IETF AQM working group is looking to document these schemes,
and independent implementations are a corner-stone of the IETF's
process for confirming the clarity of publicly available protocol
descriptions. While significant development work on all three schemes
has occured in the Linux kernel, there is very little in FreeBSD.

Project Goals

This project began in late 2015, and aims to design and implement
functionally-correct versions of CoDel, FQ-CoDel, PIE and FQ_PIE
in FreeBSD (with code BSD-licensed as much as practical). We have
chosen to do this as extensions to FreeBSD's ipfw/dummynet firewall
and traffic shaper. Implementation of these AQM schemes in FreeBSD
will:
* Demonstrate whether the publicly available documentation is
sufficient to enable independent, functionally equivalent implementations

* Provide a broader suite of AQM options for sections the networking
community that rely on FreeBSD platforms

Program Members:

* Rasool Al Saadi (developer)

* Grenville Armitage (project lead)

Acknowledgements:

This project has been made possible in part by a gift from the
Comcast Innovation Fund.

Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au>
X-No objection: core
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D6388