MFC r322812:

Avoid TCP log messages which are false positives.

Sponsored by: Multiplay

Revert the partial MFC of r313045 which broke dtrace

This removes the mbuf to ipinfo_t translator and switches tcp_autorcvbuf to
use the older mtod macro.

This was originally merged to stable/10 as part of r317375.

Reported by: markj
Reviewed by: markj, hiren
Sponsored by: Multiplay
Differential Revision: https://reviews.freebsd.org/D10769

Partial MFC r316676 and the required r313045

MFC r316676:

Use estimated RTT for receive buffer auto resizing instead of timestamps.
This is a partial MFC as stable/10 doesn't include the TCP stack
modularisation.

MFC r313045:

Add an mbuf to ipinfo_t translator to finish cleanup of mbuf passing to TCP
probes. This is a partial MFC (missing debug__output & debug__drop changes)
due to the massive amount of additional dtrace changes that would be
required for a full MFC.

Relnotes: Yes
Sponsored by: Multiplay

MFC r286227, r286443:

r286227:

Decompose TCP INP_INFO lock to increase short-lived TCP connections scalability:

- The existing TCP INP_INFO lock continues to protect the global inpcb list
stability during full list traversal (e.g. tcp_pcblist()).

- A new INP_LIST lock protects inpcb list actual modifications (inp allocation
and free) and inpcb global counters.

It allows to use TCP INP_INFO_RLOCK lock in critical paths (e.g. tcp_input())
and INP_INFO_WLOCK only in occasional operations that walk all connections.

PR: 183659
Differential Revision: https://reviews.freebsd.org/D2599
Reviewed by: jhb, adrian
Tested by: adrian, nitroboost-gmail.com
Sponsored by: Verisign, Inc.

r286443:

Fix a kernel assertion issue introduced with r286227:
Avoid too strict INP_INFO_RLOCK_ASSERT checks due to
tcp_notify() being called from in6_pcbnotify().

Reported by: Larry Rosenman <ler@lerctr.org>
Submitted by: markj, jch

MFC r307551:

Fix a double-free when an inp transitions to INP_TIMEWAIT state
after having been dropped.

This change enforces in_pcbdrop() logic in tcp_input():

"in_pcbdrop() is used by TCP to mark an inpcb as unused and avoid future packet
delivery or event notification when a socket remains open but TCP has closed."

PR: 203175
Reported by: Palle Girgensohn, Slawa Olhovchenkov
Tested by: Slawa Olhovchenkov
Reviewed by: Slawa Olhovchenkov
Approved by: gnn, Slawa Olhovchenkov
Differential Revision: https://reviews.freebsd.org/D8211
Sponsored by: Verisign, inc

MFC r271119, r272081:

r271119:

In tcp_input(), don't acquire the pcbinfo global write lock for SYN
packets targeting a listening socket. Permit to reduce TCP input
processing starvation in context of high SYN load (e.g. short-lived TCP
connections or SYN flood).

Submitted by: Julien Charbon <jcharbon@verisign.com>
Reviewed by: adrian, hiren, jhb, Mike Bentkofsky

r272081:

Catch up with r271119.

MFC r300240

Change net.inet.tcp.ecn.enable sysctl mib from a binary off/on
control to a three way setting.
0 - Totally disable ECN. (no change)
1 - Enable ECN if incoming connections request it. Outgoing
connections will request ECN. (no change from present != 0 setting)
2 - Enable ECN if incoming connections request it. Outgoing
conections will not request ECN.

Change the default value of net.inet.tcp.ecn.enable from 0 to 2.

Linux version 2.4.20 and newer, Solaris, and Mac OS X 10.5 and newer have
similar capabilities. The actual values above match Linux, and the default
matches the current Linux default.

Reviewed by: eadler
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D6386

MFC r298408:
Prevent underflows in tp->snd_wnd if the remote side ACKs more than
tp->snd_wnd. This can happen, for example, when the remote side responds
to a window probe by ACKing the one byte it contains.

MFC: r292003
Improve tcp duplicate ack processing when SACK is present.

MFC: r290122
Calculate the correct amount of bytes that are in-flight for a connection as
suggested by RFC 6675.

MFC: r292046
r290122 added 4 bytes and removed 8 in struct sackhint. Add a pad entry of 4
bytes to restore the size.

MFC r292706:

Implementation of server-side TCP Fast Open (TFO) [RFC7413].

TFO is disabled by default in the kernel build. See the top comment
in sys/netinet/tcp_fastopen.c for implementation particulars.

Differential Revision: https://reviews.freebsd.org/D4350
Sponsored by: Verisign, Inc.

MFC r288914
Add a comment specifying how we implement rfc3042.

MFC r285567:

Check TCP timestamp option flag so that the automatic receive buffer
scaling code does not use an uninitialized timestamp echo reply value
from the stack when timestamps are not enabled.

Approved by: re (gjb)

MFC r266420 (by adrian)

Ensure that the flowid hashtype is assigned to the inp if the flowid
is also assigned.

Spotted by: gallatin
Tested by: gallatin

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 r271946 and r272595:
Improve transmit sending offload, TSO, algorithm in general. This
change allows all HCAs from Mellanox Technologies to function properly
when TSO is enabled. See r271946 and r272595 for more details about
this commit.

Sponsored by: Mellanox Technologies

Fix Denial of Service in TCP packet processing.

Security: FreeBSD-SA-14:19.tcp
Approved by: re (implicit, security advisory)

MFC r266620:

Remove the prototpye for the static inline function
tcp_signature_verify_input().
The function is defined before first use already.

MFC r266597:

Remove the prototypes for things that are no longer file local but were
moved to the header file.

Was suppoed to be MFCed with: r266596
Pointy hat to: bz

MFC r266596:

Move the tcp_fields_to_host() and tcp_fields_to_net() (inline)
functions to the tcp_var.h header file in order to avoid further
duplication with upcoming commits.

Reviewed by: np

MFC r258622: dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE

MFC r258605: Convert over the TCP probes to use mtod()

MFC slacker: adrian

Revert MFC of r258821 - it was already handled by MFC of r239672.

Pointy hat to: peter

MFC r258821 - fix tcp simultaneous close

PR: kern/99188

MFC r259906: Draft-ietf-tcpm-initcwnd-05 became RFC6928.

MFC r256920:

The TCP delayed ACK logic isn't aware of LRO passing up large aggregated
segments thinking it received only one segment. This causes it to enable
the delay the ACK for 100ms to wait for another segment which may never
come because all the data was received already.

Doing delayed ACK for LRO segments is bogus for two reasons: a) it pushes
us further away from acking every other packet; b) it introduces additional
delay in responding to the sender. The latter is especially bad because it
is in the nature of LRO to aggregated all segments of a burst with no more
coming until an ACK is sent back.

Change the delayed ACK logic to detect LRO segments by being larger than
the MSS for this connection and issuing an immediate ACK for them to keep
the ACK clock ticking without interruption.

Reported by: julian, cperciva
Tested by: cperciva
Reviewed by: lstewart

Approved by: re (glebius)

MFC r285567:

Check TCP timestamp option flag so that the automatic receive buffer
scaling code does not use an uninitialized timestamp echo reply value
from the stack when timestamps are not enabled.

Approved by: re (gjb)

MFC r266420 (by adrian)

Ensure that the flowid hashtype is assigned to the inp if the flowid
is also assigned.

Spotted by: gallatin
Tested by: gallatin

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 r271946 and r272595:
Improve transmit sending offload, TSO, algorithm in general. This
change allows all HCAs from Mellanox Technologies to function properly
when TSO is enabled. See r271946 and r272595 for more details about
this commit.

Sponsored by: Mellanox Technologies

Fix Denial of Service in TCP packet processing.

Security: FreeBSD-SA-14:19.tcp
Approved by: re (implicit, security advisory)

MFC r266620:

Remove the prototpye for the static inline function
tcp_signature_verify_input().
The function is defined before first use already.

MFC r266597:

Remove the prototypes for things that are no longer file local but were
moved to the header file.

Was suppoed to be MFCed with: r266596
Pointy hat to: bz

MFC r266596:

Move the tcp_fields_to_host() and tcp_fields_to_net() (inline)
functions to the tcp_var.h header file in order to avoid further
duplication with upcoming commits.

Reviewed by: np

MFC r258622: dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE

MFC r258605: Convert over the TCP probes to use mtod()

MFC slacker: adrian

Revert MFC of r258821 - it was already handled by MFC of r239672.

Pointy hat to: peter

MFC r258821 - fix tcp simultaneous close

PR: kern/99188

MFC r259906: Draft-ietf-tcpm-initcwnd-05 became RFC6928.

MFC r256920:

The TCP delayed ACK logic isn't aware of LRO passing up large aggregated
segments thinking it received only one segment. This causes it to enable
the delay the ACK for 100ms to wait for another segment which may never
come because all the data was received already.

Doing delayed ACK for LRO segments is bogus for two reasons: a) it pushes
us further away from acking every other packet; b) it introduces additional
delay in responding to the sender. The latter is especially bad because it
is in the nature of LRO to aggregated all segments of a burst with no more
coming until an ACK is sent back.

Change the delayed ACK logic to detect LRO segments by being larger than
the MSS for this connection and issuing an immediate ACK for them to keep
the ACK clock ticking without interruption.

Reported by: julian, cperciva
Tested by: cperciva
Reviewed by: lstewart

Approved by: re (glebius)