There are various cases where we modify the inp_vflag and inp_inc.inc_flags
fields during a syscall, but don't restore those fields if the operation
fails. This can leave the inp structure in an inconsistent state and cause
various problems.

Restore the inp_vflag and inp_inc.inc_flags fields when the underlying
operation fails and the inp could be in an inconsistent state.

This is a direct commit to the branch as the code is different enough in
the other branches to make it difficult to resolve a merge.

Submitted by: jtl@
Reported by: Jakub Jirasek, Secunia Research at Flexera
Reviewed by: jhb@
Approved by: so
Security: FreeBSD-EN-18:11.listen
Security: CVE-2018-6925

MFC r295549:
Loopback addresses are 127.0.0.0/8, not 127.0.0.1/32.

MFC r295668:
Improve the teardown of the SCTP stack.

MFC r295670:
Whitespace changes.

MFC r295708:
Address a warning reported by D5245 / PVS.

MFC r295709:
Code cleanup which will silence a warning in PVS / D5245.

MFC r295710:
Add protection code for issues reported by PVS / D5245.

MFC r295771:
Fix reporting of mapped addressed in getpeername() and getsockname() for
IPv6 SCTP sockets.
This bugs were found because of an issue reported by PVS / D5245.

MFC r295772:
Add some protection code.

MFC r295773:
Add protection code.

MFC r295805:
Use the SCTP level pointer, not the interface level.

MFC r295929:
Don't leak an address in an error path.

Approved by: re (marius)

MFC r291904:
Fix the allocation of outgoing streams:
* When processing a cookie, use the number of
streams announced in the INIT-ACK.
* When sending an INIT-ACK for an existing
association, use the value from the association,
not from the end-point.

MFC r285877:
Move including netinet/icmp6.h around to avoid a problem when including
netinet/icmp6.h and net/netmap.h. Both use ni_flags...
This allows to build multistack with SCTP support.

o Fix SCTP ICMPv6 error message vulnerability. [SA-16:01.sctp]
o Fix Linux compatibility layer incorrect futex handling. [SA-16:03.linux]
o Fix Linux compatibility layer setgroups(2) system call. [SA-16:04.linux]
o Fix TCP MD5 signature denial of service. [SA-16:05.tcp]
o Fix insecure default bsnmpd.conf permissions. [SA-16:06.bsnmpd]

Security: FreeBSD-SA-16:01.sctp, CVE-2016-1879
Security: FreeBSD-SA-16:03.linux, CVE-2016-1880
Security: FreeBSD-SA-16:04.linux, CVE-2016-1881
Security: FreeBSD-SA-16:05.tcp, CVE-2016-1882
Security: FreeBSD-SA-16:06.bsnmpd, CVE-2015-5677

MFC r284515:
Add FIB support for SCTP.
This fixes https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200379

PR: 200379

MFC r283650:

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

MFC r276914:

Minimize the usage of SCTP_BUF_IS_EXTENDED.
This should help Robert...

MFC r275868:

Plug a memory leak in an error code path.

Reported by: Coverity
CID: 1018936

MFC r275358 r275483 r276982 - Removing M_FLOWID by hps@

r275358:
Start process of removing the use of the deprecated "M_FLOWID" flag
from the FreeBSD network code. The flag is still kept around in the
"sys/mbuf.h" header file, but does no longer have any users. Instead
the "m_pkthdr.rsstype" field in the mbuf structure is now used to
decide the meaning of the "m_pkthdr.flowid" field. To modify the
"m_pkthdr.rsstype" field please use the existing "M_HASHTYPE_XXX"
macros as defined in the "sys/mbuf.h" header file.

This patch introduces new behaviour in the transmit direction.
Previously network drivers checked if "M_FLOWID" was set in "m_flags"
before using the "m_pkthdr.flowid" field. This check has now now been
replaced by checking if "M_HASHTYPE_GET(m)" is different from
"M_HASHTYPE_NONE". In the future more hashtypes will be added, for
example hashtypes for hardware dedicated flows.

"M_HASHTYPE_OPAQUE" indicates that the "m_pkthdr.flowid" value is
valid and has no particular type. This change removes the need for an
"if" statement in TCP transmit code checking for the presence of a
valid flowid value. The "if" statement mentioned above is now a direct
variable assignment which is then later checked by the respective
network drivers like before.

r275483:
Remove M_FLOWID from SCTP code.

r276982:
Remove no longer used "M_FLOWID" flag from mbuf.h and update the netisr
manpage.

Note: The FreeBSD version has been bumped.

Reviewed by: hps, tuexen
Sponsored by: Limelight Networks

MFC r270673:
Announce SCTP support in the kern.features sysctl variables.

MFC r270859:
Enable SCTP support. It runs perfectly fine on a Wandboard quad.

MFC r271204 with manual intervention:
Fix the handling of sysctl variables when used with VIMAGE.
While there do some cleanup of the code.

MFC r271209:
Fix a leak of an address, if the address is scheduled for removal
and the stack is torn down.
Thanks to Peter Bostroem and Jiayang Liu from Google for reporting the
issue.

MFC r271219:
Use SYSCTL_PROC instead of SYSCTL_VNET_PROC.
Suggested by: glebius@

MFC r271221:
Use union sctp_sockstore instead of struct sockaddr_storage. This
eliminates some warnings when building in userland.
Thanks to Patrick Laimbock for reporting this issue.
Remove also some unnecessary casts.
There should be no functional change.

MFC r271228:
Address another warnings reported by Patrick Laimbock when compiling
in userspace. While there, improve consistency.

MFC r271230:
Address warnings generated by the clang analyzer.

Approved by: re (kib)

MFC r256556:
Remove a buggy comparision when setting manually the path MTU.
After fixing, the comparision would have become redundant.
Thanks to Andrew Galante for reporting the issue.

MFC r257272:
Fix compilation if SCTP_DONT_DO_PRIVADDR_SCOPE is defined.
The issue was reported by Andrew Galante.

MFC r257274:
Fix the value of *optlen when calling getsockopt() for
SCTP_REMOTE_UDP_ENCAPS_PORT.
This issue was reported by Andrew Galante.

MFC r257359:
Terminate a debug output with a \n.

MFC r257555:
Changes from upstream to improve compilation when INET or INET6
or none of them is defined.

MFC r257574:
Unlock the lock before destroying it.
This issue was reported by Andrew Galante.

MFC r257800:
Use htons()/ntohs() appropriately.
These issues were reported by Andrew Galante.

MFC r257803:
Make sure that we don't try to build an ASCONF-ACK chunk
larger than what fits in the the mbuf cluster.
This issue was reported by Andrew Galante.

MFC r257804:
Get rid of the artification limitation enforced by
SCTP_AUTH_RANDOM_SIZE_MAX.
This was suggested by Andrew Galante.

MFC r258221:
Cleanups which result in fixes which have been made upstream
and where partially suggested by Andrew Galante.
There is no functional change in FreeBSD.

MFC r258224:
When determining if an address belongs to an stcb, take the address family
into account for wildcard bound endpoints.

MFC r258228:
Remove a stray write operation.

MFC r258235:
Use SCTP_PR_SCTP_TTL when the user provides a positive
timetolive in sctp_sendmsg().

Approved by: re@

MFC r284515:
Add FIB support for SCTP.
This fixes https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200379

PR: 200379

MFC r283650:

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

MFC r276914:

Minimize the usage of SCTP_BUF_IS_EXTENDED.
This should help Robert...

MFC r275868:

Plug a memory leak in an error code path.

Reported by: Coverity
CID: 1018936

MFC r275358 r275483 r276982 - Removing M_FLOWID by hps@

r275358:
Start process of removing the use of the deprecated "M_FLOWID" flag
from the FreeBSD network code. The flag is still kept around in the
"sys/mbuf.h" header file, but does no longer have any users. Instead
the "m_pkthdr.rsstype" field in the mbuf structure is now used to
decide the meaning of the "m_pkthdr.flowid" field. To modify the
"m_pkthdr.rsstype" field please use the existing "M_HASHTYPE_XXX"
macros as defined in the "sys/mbuf.h" header file.

This patch introduces new behaviour in the transmit direction.
Previously network drivers checked if "M_FLOWID" was set in "m_flags"
before using the "m_pkthdr.flowid" field. This check has now now been
replaced by checking if "M_HASHTYPE_GET(m)" is different from
"M_HASHTYPE_NONE". In the future more hashtypes will be added, for
example hashtypes for hardware dedicated flows.

"M_HASHTYPE_OPAQUE" indicates that the "m_pkthdr.flowid" value is
valid and has no particular type. This change removes the need for an
"if" statement in TCP transmit code checking for the presence of a
valid flowid value. The "if" statement mentioned above is now a direct
variable assignment which is then later checked by the respective
network drivers like before.

r275483:
Remove M_FLOWID from SCTP code.

r276982:
Remove no longer used "M_FLOWID" flag from mbuf.h and update the netisr
manpage.

Note: The FreeBSD version has been bumped.

Reviewed by: hps, tuexen
Sponsored by: Limelight Networks

MFC r270673:
Announce SCTP support in the kern.features sysctl variables.

MFC r270859:
Enable SCTP support. It runs perfectly fine on a Wandboard quad.

MFC r271204 with manual intervention:
Fix the handling of sysctl variables when used with VIMAGE.
While there do some cleanup of the code.

MFC r271209:
Fix a leak of an address, if the address is scheduled for removal
and the stack is torn down.
Thanks to Peter Bostroem and Jiayang Liu from Google for reporting the
issue.

MFC r271219:
Use SYSCTL_PROC instead of SYSCTL_VNET_PROC.
Suggested by: glebius@

MFC r271221:
Use union sctp_sockstore instead of struct sockaddr_storage. This
eliminates some warnings when building in userland.
Thanks to Patrick Laimbock for reporting this issue.
Remove also some unnecessary casts.
There should be no functional change.

MFC r271228:
Address another warnings reported by Patrick Laimbock when compiling
in userspace. While there, improve consistency.

MFC r271230:
Address warnings generated by the clang analyzer.

Approved by: re (kib)

MFC r256556:
Remove a buggy comparision when setting manually the path MTU.
After fixing, the comparision would have become redundant.
Thanks to Andrew Galante for reporting the issue.

MFC r257272:
Fix compilation if SCTP_DONT_DO_PRIVADDR_SCOPE is defined.
The issue was reported by Andrew Galante.

MFC r257274:
Fix the value of *optlen when calling getsockopt() for
SCTP_REMOTE_UDP_ENCAPS_PORT.
This issue was reported by Andrew Galante.

MFC r257359:
Terminate a debug output with a \n.

MFC r257555:
Changes from upstream to improve compilation when INET or INET6
or none of them is defined.

MFC r257574:
Unlock the lock before destroying it.
This issue was reported by Andrew Galante.

MFC r257800:
Use htons()/ntohs() appropriately.
These issues were reported by Andrew Galante.

MFC r257803:
Make sure that we don't try to build an ASCONF-ACK chunk
larger than what fits in the the mbuf cluster.
This issue was reported by Andrew Galante.

MFC r257804:
Get rid of the artification limitation enforced by
SCTP_AUTH_RANDOM_SIZE_MAX.
This was suggested by Andrew Galante.

MFC r258221:
Cleanups which result in fixes which have been made upstream
and where partially suggested by Andrew Galante.
There is no functional change in FreeBSD.

MFC r258224:
When determining if an address belongs to an stcb, take the address family
into account for wildcard bound endpoints.

MFC r258228:
Remove a stray write operation.

MFC r258235:
Use SCTP_PR_SCTP_TTL when the user provides a positive
timetolive in sctp_sendmsg().

Approved by: re@