MFC r356660: Avoid division by zero

Fix division by zero issue.

Thanks to Stas Denisov for reporting the issue for the userland stack
and providing a fix.

MFC r336511:
Whitespace changes due to changes in ident.

Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC r310590:

Whitespace changes.

The toolchain for processing the sources has been updated. No functional
change.

MFC r309682:

Cleanup the names of SSN, SID, TSN, FSN, PPID and MID.

This made a couple of bugs visible in handling SSN wrap-arounds
when using DATA chunks. Now bulk transfer seems to work fine...
This fixes the issue reported in
https://github.com/sctplab/usrsctp/issues/111

MFC r309607:

Whitespace changes.

The tools using to generate the sources has been updated and produces
different whitespaces. Commit this seperately to avoid intermixing
these with real code changes.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

netinet/sctp*: minor spelling fixes in comments.

No functional change.

Reviewed by: tuexen

Add const to several constants. Thanks to Nicholas Nethercote for
providing the patch via
https://bugzilla.mozilla.org/show_bug.cgi?id=1255655

MFC after: 1 week

Fix style issues around existing SDT probes.

- Use SDT_PROBE<N>() instead of SDT_PROBE(). This has no functional effect
at the moment, but will be needed for some future changes.
- Don't hardcode the module component of the probe identifier. This is
set automatically by the SDT framework.

MFC after: 1 week

Fix and cleanup the debug information. This has no user-visible changes.
Thanks to Irene Ruengeler for proving a patch.

MFC after: 3 days

Add a SCTP socket option to limit the cwnd for each path.

MFC after: 1 month

Small cleanup which addresses a warning regaring the truncation
of a 64-bit entity to a 32-bit entity. This issue was reported by
Peter Kasting from Google.

MFC after: 3 days

Get rid of a gcc'ism.

MFC after: 10 days

Using %p in a format string requires a void *.

MFC after: 10 days

Use consistent text at the begining of the files.

MFC after: 3 days

Use SCTP_PRINTF() instead of printf() in all SCTP sources.

MFC after: 3 days

Address issues found by clang. While there, fix also some style
issues.

MFC after: 3 months.

Fix unused parameter warnings.
While there, fix some whitespace issues.

MFC after: 3 months.

The result of a joint work between rrs@ and myself at the IETF:
* Decouple the path supervision using a separate HB timer per path.
* Add support for potentially failed state.
* Bring back RTO.min to 1 second.
* Accept packets on IP-addresses already announced via an ASCONF
* While there: do some cleanups.

Approved by: re@
MFC after: 2 months.

Implement Resource Pooling V2 and an MPTCP like congestion
control.
Based on a patch received from Martin Becke.

MFC after: 2 weeks.

Tunes and fixes the new DC-CC to seem to hit the
right mix. Still may need some tweaks but it
appears to almost not give away too much to an
RFC2581 flow, but can really minimize the amount of
buffers used in the net.

MFC after: 3 months

Adds a new Congestion Control that helps reduce
the RTT that a flow will build up in buffers in
transit. It is a slight modification to RFC2581
but is more friendly i.e. less aggressive.

MFC after: 3 months

Improvements to CC modules:
1) Add four new points that allow you to get more information
to cc algo's
2) Fix the case where user changes module on a existing TCB, in
such a case, the initialization module needs to be called on all nets.
3) Move htcp_cc structure to a union that other modules can use.
4) Add 5th point for get/set socket options for cc_module specific options

MFC after: 2 months

* Fix several bugs where the scaled versions of srtt and rttvar
where used incorrectly.
* Use appropriate variable names for RTO instead of RTT.

MFC after: 3 months.

1) Typo correction in comments and one spacing change.
2) Mass update to all copyrights.
MFC after: 3 Months

1) Move per John Baldwin to mp_maxid
2) Some signed/unsigned errors found by Mac OS compiler (from Michael)
3) a couple of copyright updates on the effected files.

MFC after: 3 months

1) Allow a chunk to track the cwnd it was at when sent.
2) Add separate max-bursts for retransmit and hb. These
are set to sysctlable values but not settable via the
socket api. This makes sure we don't blast out HB's or
fast-retransmits.
3) Determine on the first data transmission on a net if
its local-lan (by being under or over a RTT). This
can later be used to think about different algorithms
based on locallan vs big-i (experimental)
4) The cwnd should NOT be allowed to grow when an ECNEcho
is seen (TCP has this same bug). We fix this in SCTP
so an ECNe being seen prevents an advance of cwnd.
5) CWR's should not be sent multiple times to the
same network, instead just updating the TSN being
transmitted if needed.

MFC after: 1 Month

More ECN fixes:
1) We now remove ECN-Nonce since it will no longer continue as a I-D
2) Eliminate last_tsn_echo, this tied us to an assoc not the net
and thus we were not doing m-homing on the ECN-Echo senders side right.
3) Increment the count going out even if the TSN in lower in the pending
ECN-Echo, this way the receiver knows exactly how many packets were
marked even with network re-ordering
4) Fix so we DO NOT stop doing delayed sack if a ECN Echo is in queue
MFC after: 1 month

Change infrastructure for SCTP_MAX_BURST to allow compliance
with the latest socket API ID. Especially it can be disabled.

Full compliance needs changing the structure used in the
socket option. Since this breaks the API, it will be a
seperate commit which will not be MFCed to stable/8.

MFC after: 3 months.

Cleanup the management of CC functions.

MFC after: 3 months.

Add support for resource pooling to CMT.
An original version of the patch was developed by Martin Becke
and Thomas Dreibholz.

MFC after: 3 months

Provide a possibility to configure the inital congestion window to the
value defined in RFC 4960.

MFC after: 3 months.

Improve plausibility check in sctp_handle_sack().
Allow cmt_on_off to support values 0 (no CMT), 1 (CMT), and 2 (CMT/RP).

MFC after: 3 months.

Adds new dtrace for cwnd functions and lay's
groundwork for future dtrace points (rwnd flightsize etc).

MFC after: 2 months

Make the initial congestion window configurable via sysctl.

MFC after: 2 weeks.

* Use !TAILQ_EMPTY() for checking if a tail queue is not empty.
* Remove assignment without any effect.

MFC after: 2 weeks.

Fix the switching on/off of CMT using sysctl and socket option.
Fix the switching on/off of PF and NR-SACKs using sysctl.
Add minor improvement in handling malloc failures.
Improve the address checks when sending.

MFC after: 4 weeks

Bugfix: Use formula from section 7.2.3 of RFC 4960. Reported by Martin Becke.

Approved by: rrs (mentor)
MFC after: 3 days

- Macro-izes the packed declaration in all headers.
- Vimage prep - these are major restructures to move
all global variables to be accessed via a macro or two.
The variables all go into a single structure.
- Asconf address addition tweaks (add_or_del Interfaces)
- Fix rwnd calcualtion to be more conservative.
- Support SACK_IMMEDIATE flag to skip delayed sack
by demand of peer.
- Comment updates in the sack mapping calculations
- Invarients panic added.
- Pre-support for UDP tunneling (we can do this on
MAC but will need added support from UDP to
get a "pipe" of UDP packets in.
- clear trace buffer sysctl added when local tracing on.

Note the majority of this huge patch is all the vimage prep stuff :-)

- Adds support for the multi-asconf (From Kozuka-san)
- Adds some prepwork (Not all yet) for vimage in particular
support the delete the sctppcbinfo.xx structs. There is
still a leak in here if it were to be called plus we stil
need the regrouping (From Me and Michael Tuexen)
- Adds support for UDP tunneling. For BSD there is no
socket yet setup so its disabled, but major argument
changes are in here to emcompass the passing of the port
number (zero when you don't have a udp tunnel, the default
for BSD). Will add some hooks in UDP here shortly (discussed
with Robert) that will allow easy tunneling. (Mainly from
Peter Lei and Michael Tuexen with some BSD work from me :-D)
- Some ease for windows, evidently leave is reserved by their
compile move label leave: -> out:

MFC after: 1 week

- Define changes in sctp.h
- Bug in CA that does not get us incrementing the PBA properly which
made us more conservative.
- comment updated in sctp_input.c
- memsets added before we log
- added arg to hmac id's
MFC after: 2 weeks

- Locking compatiability changes. This involves adding
additional flags to many function calls. The flags only
get used in BSD when we compile with lock testing. These
flags allow apple to escape the "giant" lock it holds on
the socket and have more fine-grained locking in the NKE.
It also allows us to test (with witness) the locking used
by apple via a compile switch (manually applied).

Approved by: re@freebsd.org(B Mah)

- added pre-checks to the bindx call.
- use proper tick gathering macro instead of ticks directly.
- Placed reasonable boundaries on sets that a user can do
that are converted to ticks from ms.
- Fix CMT_PF to always check to be sure CMT is on.
- Fix ticks use of CMT_PF.
- put back code to allow asconfs to be queued while INITs are in flight
and before the assoc is established.
- During window probes, an ack'd packet might be left with the window
probe mark on it causing it to be retransmitted. Change so that
the flight decrease macro clears the window_probe mark.
- Additional logging flight size/reading and ASOC LOG. This
is only enabled if you manually insert things into opt_sctp.h
since its a set of debug code only.
- Found an interesting SMP race in the way data was appended which
could cause a reader to lose a part of a message, had to
reorder when we marked the message was complete to after
the data was appended.
- bug in ADD-IP for the subset bound socket case when the peer has only
one address
- fix ASCONF implicit success/error handling case
- proper support of jails in Freebsd 6>
- copy out the timeval for the 64 bit sparc world on cookie-echo
alignment error crashes without this).
Approved by: re(Ken Smith)

- Modular congestion control, with RFC2581 being the default.
- CMT_PF states added (w/sysctl to turn the PF version on)
- sctp_input.c had a missing incr of cookie case when the
auth was bad. This meant a free was called without an
increment to refcnt, added increment like rest of code.
- There was a case, unlikely, when the scope of the destination
changed (this is a TSNH case). In that case, it would not free
the alloc'ed asoc (in sctp_input.c).
- When listed addresses found a colliding cookie/Init, then
the collided upon tcb was not unlocked in sctp_pcb.c
- Add error checking on arguments of sctp_sendx(3) to prevent it from
referencing a NULL pointer.
- Fix an error return of sctp_sendx(3), it was returing
ENOMEM not -1.
- Get assoc id was changed to use the sanctified socket api
method for getting a assoc id (PEER_ADDR_INFO instead of
PEER_ADDR_PARAMS).
- Fix it so a peeled off socket will get a proper error return
if it trys to send to a different address then it is connected to.
- Fix so that select_a_stream can avoid an endless loop that
could hang a caller.
- time_entered (state set time) was not being set in all cases
to the time we went established.
Approved by: re(ken smith)