of them have to do with TFO. Even the default stack
had one of the issues:
1) We need to make sure for rack that we don't advance
snd_nxt beyond iss when we are not doing fast open. We
otherwise can get a bunch of SYN's sent out incorrectly
with the seq number advancing.
2) When we complete the 3-way handshake we should not ever
append to reassembly if the tlen is 0, if TFO is enabled
prior to this fix we could still call the reasemmbly. Note
this effects all three stacks.
3) Rack like its cousin BBR should track if a SYN is on a
send map entry.
4) Both bbr and rack need to only consider len incremented on a SYN
if the starting seq is iss, otherwise we don't increment len which
may mean we return without adding a sendmap entry.
This work was done in collaberation with Michael Tuexen, thanks for
all the testing!
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D25000
Overly conservative data receivers may ignore the CWR flag
on other packets, and keep ECE latched. This can result in
continous reduction of the congestion window, and very poor
performance when ECN is enabled.
Reviewed by: rgrimes (mentor), rrs
Approved by: rgrimes (mentor), tuexen (mentor)
MFC after: 3 days
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D23364
When receiving a parallel SYN in SYN-SENT state, remove all the
options only we supported locally before sending the SYN,ACK.
This addresses a consistency issue on parallel opens.
Also, on such a parallel open, the stack could be coaxed into
running with timestamps enabled, even if administratively disabled.
Reviewed by: tuexen (mentor)
Approved by: tuexen (mentor)
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D23371
While testing simultaneous open TCP with ECN, found that
negotiation fails to arrive at the expected final state.
Reviewed by: tuexen (mentor)
Approved by: tuexen (mentor), rgrimes (mentor)
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D23373
help of Michael Tuexen. There was some accounting
errors with TCPFO for bbr and also for both rack
and bbr there was a FO case where we should be
jumping to the just_return_nolock label to
exit instead of returning 0. This of course
caused no timer to be running and thus the
stuck sessions.
Reported by: Michael Tuexen and Skyzaller
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D24852
causes so_reuseport_lb_test to fail since it slows down how quickly the program runs until the timeout occurs
and fails the test
Sponsored by: Netflix inc.
Differential Revision: https://reviews.freebsd.org/D24747
a few extra arguments). Recently that changed to only have one arg extra so
that two ifdefs around the call are no longer needed. Lets take out the
extra ifdef and arg.
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D24736
1) When BBR retransmits the syn it was messing up the snd_max
2) When we need to send a RST we might not send it when we should
Reported by: ankitraheja09@gmail.com
Sponsored by: Netflix.com
Differential Revision: https://reviews.freebsd.org/D24693
This was only triggered when setting the IPPROTO_TCP level socket
option TCP_DELACK.
This issue was found by runnning an instance of SYZKALLER.
Reviewed by: rrs
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D24690
have been made in rack and adds a few fixes in BBR. This also
removes any possibility of incorrectly doing OOB data the stacks
do not support it. Should fix the skyzaller crashes seen in the
past. Still to fix is the BBR issue just reported this weekend
with the SYN and on sending a RST. Note that this version of
rack can now do pacing as well.
Sponsored by:Netflix Inc
Differential Revision:https://reviews.freebsd.org/D24576
which can cause a TCP client to use invalid or stale TCP sequence numbers for ACK packets.
Packets with old sequence numbers are ignored and not used to update the send window size.
This might cause the TCP session to hang indefinitely under some circumstances.
Reported by: Cui Cheng
Reviewed by: tuexen (mentor), rgrimes (mentor)
Approved by: tuexen (mentor), rgrimes (mentor)
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D24515
by not including the SYN bit sequence space in cwnd related calculations.
Snd_und is adjusted explicitly in all cases, outside the cwnd update, instead.
This fixes an off-by-one conformance issue with regular TCP sessions not
using Appropriate Byte Counting (RFC3465), sending one more packet during
the initial window than expected.
PR: 235256
Reviewed by: tuexen (mentor), rgrimes (mentor)
Approved by: tuexen (mentor), rgrimes (mentor)
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D19000
This change is build on top of nexthop objects introduced in r359823.
Nexthops are separate datastructures, containing all necessary information
to perform packet forwarding such as gateway interface and mtu. Nexthops
are shared among the routes, providing more pre-computed cache-efficient
data while requiring less memory. Splitting the LPM code and the attached
data solves multiple long-standing problems in the routing layer,
drastically reduces the coupling with outher parts of the stack and allows
to transparently introduce faster lookup algorithms.
Route caching was (re)introduced to minimise (slow) routing lookups, allowing
for notably better performance for large TCP senders. Caching works by
acquiring rtentry reference, which is protected by per-rtentry mutex.
If the routing table is changed (checked by comparing the rtable generation id)
or link goes down, cache record gets withdrawn.
Nexthops have the same reference counting interface, backed by refcount(9).
This change merely replaces rtentry with the actual forwarding nextop as a
cached object, which is mostly mechanical. Other moving parts like cache
cleanup on rtable change remains the same.
Differential Revision: https://reviews.freebsd.org/D24340
in all cases, by adjust snd_una right after the
connection initialization, to include the one byte
in sequence space occupied by the SYN bit.
This does not change the regular ACK processing,
while making the BYTES_THIS_ACK macro to work properly.
PR: 235256
Reviewed by: tuexen (mentor), rgrimes (mentor)
Approved by: tuexen (mentor), rgrimes (mentor)
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D19000
for IPv4, enabled only for IPv6, and enabled for IPv4 and IPv6.
The current blackhole detection might classify a temporary outage as
an MTU issue and reduces permanently the MSS. Since the consequences of
such a reduction due to a misclassification are much more drastically
for IPv4 than for IPv6, allow the administrator to enable it for IPv6 only.
Reviewed by: bcr@ (man page), Richard Scheffenegger
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D24219
these are kernel modules. Also add a KMOD_TCPSTAT_ADD and use that
instead of TCPSTAT_ADD.
Reviewed by: jtl@, rrs@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D23904
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
in FreeBSD the bits that disabled stats
when netflix-stats is not defined is no longer
needed. Lets remove these bits so that we
will properly use stats per its definition
in BBR and Rack.
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D23088
and not only for the DCTCP congestion control.
Submitted by: Richard Scheffenegger
Reviewed by: rgrimes, tuexen@, Cheng Cui
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D23119
recovery. This is required by RFC 3168.
Submitted by: Richard Scheffenegger
Reviewed by: rgrimes@, tuexen@, Cheng Cui
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D23118
indicates that ECN should be negotiated for the client side.
Submitted by: Richard Scheffenegger
Reviewed by: rgrimes@, tuexen@
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D23228
This allows the data sender to increase the CWND faster.
Submitted by: Richard Scheffenegger
Reviewed by: rgrimes@, tuexen@, Cheng Cui
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D22670
including user data in the SYN-ACK. When DSACK support was added in
r347382, an immediate ACK was sent even for the received SYN with
user data. This patch fixes that and allows again to send user data with
the SYN-ACK.
Reported by: Jeremy Harris
Reviewed by: Richard Scheffenegger, rrs@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D23212
Virtualise tcp_always_keepalive, TCP and UDP log_in_vain. All three are
set in the netoptions startup script, which we would love to run for VNETs
as well [1].
While virtualising the log_in_vain sysctls seems pointles at first for as
long as the kernel message buffer is not virtualised, it at least allows
an administrator to debug the base system or an individual jail if needed
without turning the logging on for all jails running on a system.
PR: 243193 [1]
MFC after: 2 weeks
tcp_outflags isn't used in this source file and compilation failed with
external GCC on sparc64. I'm not sure why only that case failed (perhaps
inconsistent -Werror config) but it is a legitimate issue to fix.
Reviewed by: tuexen
Differential Revision: https://reviews.freebsd.org/D23068
also commonizes the functions that both the freebsd and
rack stack uses.
Sponsored by:Netflix Inc
Differential Revision: https://reviews.freebsd.org/D23052
gets both rack and bbr ready for the completion of the STATs
framework in FreeBSD. For now if you don't have both NF_stats and
stats on it disables them. As soon as the rest of the stats framework
lands we can remove that restriction and then just uses stats when
defined.
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D22479
This allows adding more ECN related flags in the future.
No functional change intended.
Submitted by: Richard Scheffenegger
Reviewed by: rrs@, tuexen@
Differential Revision: https://reviews.freebsd.org/D22497
to add support for L4S or SCE, which require processing of the IP TOS
field.
Submitted by: Richard Scheffenegger
Reviewed by: rgrimes@, rrs@, tuexen@
Differential Revision: https://reviews.freebsd.org/D22426
in the network epoch, we can greatly simplify synchronization.
Remove all unneccesary epoch enters hidden under INP_INFO_RLOCK macro.
Remove some unneccesary assertions and convert necessary ones into the
NET_EPOCH_ASSERT macro.
happens is we are more delayed in the pacer calling in so
we remove the stack from the pacer and recalculate how
much time is left after all data has been acknowledged. However
the comparision was backwards so we end up with a negative
value in the last_pacing_delay time which causes us to
add in a huge value to the next pacing time thus stalling
the connection.
Reported by: vm2.finance@gmail.com
including the TCP header in the first IP packet.
Enforce this in tcp_output(). In addition make sure that at least
one byte payload fits in the TCP segement to allow making progress.
Without this check, a kernel with INVARIANTS will panic.
This issue was found by running an instance of syzkaller.
Reviewed by: jtl@
MFC after: 3 days
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21665
for RACK specific socket options.
These issues were found by a syzkaller instance.
Reviewed by: rrs@
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21825
is a completely separate TCP stack (tcp_bbr.ko) that will be built only if
you add the make options WITH_EXTRA_TCP_STACKS=1 and also include the option
TCPHPTS. You can also include the RATELIMIT option if you have a NIC interface that
supports hardware pacing, BBR understands how to use such a feature.
Note that this commit also adds in a general purpose time-filter which
allows you to have a min-filter or max-filter. A filter allows you to
have a low (or high) value for some period of time and degrade slowly
to another value has time passes. You can find out the details of
BBR by looking at the original paper at:
https://queue.acm.org/detail.cfm?id=3022184
or consult many other web resources you can find on the web
referenced by "BBR congestion control". It should be noted that
BBRv1 (which this is) does tend to unfairness in cases of small
buffered paths, and it will usually get less bandwidth in the case
of large BDP paths(when competing with new-reno or cubic flows). BBR
is still an active research area and we do plan on implementing V2
of BBR to see if it is an improvement over V1.
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D21582
it wasn't taking the IP level options into account. This patch fixes this.
In addition, it also corrects a KASSERT and adds protection code to assure
that the IP header chain and the TCP head fit in the first fragment as
required by RFC 7112.
Reviewed by: rrs@
MFC after: 3 days
Sponsored by: Nertflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21666
This fixes hitting a KASSERT with a valid packet exchange.
Reviewed by: rrs@, Richard Scheffenegger
MFC after: 3 days
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21567
to add BBR. These changes make it so you can get an
array of timestamps instead of a compressed ack/data segment.
BBR uses this to aid with its delivery estimates. We also
now (via Drew's suggestions) will not go to the expense of
the tcb lookup if no stack registers to want this feature. If
HPTS is not present the feature is not present either and you
just get the compressed behavior.
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D21127
* Convert the TCP delayed ACK timer from ms to ticks as required.
This fixes the timer on platforms with hz != 1000.
* Don't delay acknowledgements which report duplicate data using
DSACKs.
Reviewed by: rrs@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21512
The lowest SACK block is used when multiple Blocks would be elegible as
DSACK blocks ACK blocks get reordered - while maintaining the ordering of
SACK blocks not relevant in the DSACK context is maintained.
Reviewed by: rrs@, tuexen@
Obtained from: Richard Scheffenegger
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21038
KTLS adds support for in-kernel framing and encryption of Transport
Layer Security (1.0-1.2) data on TCP sockets. KTLS only supports
offload of TLS for transmitted data. Key negotation must still be
performed in userland. Once completed, transmit session keys for a
connection are provided to the kernel via a new TCP_TXTLS_ENABLE
socket option. All subsequent data transmitted on the socket is
placed into TLS frames and encrypted using the supplied keys.
Any data written to a KTLS-enabled socket via write(2), aio_write(2),
or sendfile(2) is assumed to be application data and is encoded in TLS
frames with an application data type. Individual records can be sent
with a custom type (e.g. handshake messages) via sendmsg(2) with a new
control message (TLS_SET_RECORD_TYPE) specifying the record type.
At present, rekeying is not supported though the in-kernel framework
should support rekeying.
KTLS makes use of the recently added unmapped mbufs to store TLS
frames in the socket buffer. Each TLS frame is described by a single
ext_pgs mbuf. The ext_pgs structure contains the header of the TLS
record (and trailer for encrypted records) as well as references to
the associated TLS session.
KTLS supports two primary methods of encrypting TLS frames: software
TLS and ifnet TLS.
Software TLS marks mbufs holding socket data as not ready via
M_NOTREADY similar to sendfile(2) when TLS framing information is
added to an unmapped mbuf in ktls_frame(). ktls_enqueue() is then
called to schedule TLS frames for encryption. In the case of
sendfile_iodone() calls ktls_enqueue() instead of pru_ready() leaving
the mbufs marked M_NOTREADY until encryption is completed. For other
writes (vn_sendfile when pages are available, write(2), etc.), the
PRUS_NOTREADY is set when invoking pru_send() along with invoking
ktls_enqueue().
A pool of worker threads (the "KTLS" kernel process) encrypts TLS
frames queued via ktls_enqueue(). Each TLS frame is temporarily
mapped using the direct map and passed to a software encryption
backend to perform the actual encryption.
(Note: The use of PHYS_TO_DMAP could be replaced with sf_bufs if
someone wished to make this work on architectures without a direct
map.)
KTLS supports pluggable software encryption backends. Internally,
Netflix uses proprietary pure-software backends. This commit includes
a simple backend in a new ktls_ocf.ko module that uses the kernel's
OpenCrypto framework to provide AES-GCM encryption of TLS frames. As
a result, software TLS is now a bit of a misnomer as it can make use
of hardware crypto accelerators.
Once software encryption has finished, the TLS frame mbufs are marked
ready via pru_ready(). At this point, the encrypted data appears as
regular payload to the TCP stack stored in unmapped mbufs.
ifnet TLS permits a NIC to offload the TLS encryption and TCP
segmentation. In this mode, a new send tag type (IF_SND_TAG_TYPE_TLS)
is allocated on the interface a socket is routed over and associated
with a TLS session. TLS records for a TLS session using ifnet TLS are
not marked M_NOTREADY but are passed down the stack unencrypted. The
ip_output_send() and ip6_output_send() helper functions that apply
send tags to outbound IP packets verify that the send tag of the TLS
record matches the outbound interface. If so, the packet is tagged
with the TLS send tag and sent to the interface. The NIC device
driver must recognize packets with the TLS send tag and schedule them
for TLS encryption and TCP segmentation. If the the outbound
interface does not match the interface in the TLS send tag, the packet
is dropped. In addition, a task is scheduled to refresh the TLS send
tag for the TLS session. If a new TLS send tag cannot be allocated,
the connection is dropped. If a new TLS send tag is allocated,
however, subsequent packets will be tagged with the correct TLS send
tag. (This latter case has been tested by configuring both ports of a
Chelsio T6 in a lagg and failing over from one port to another. As
the connections migrated to the new port, new TLS send tags were
allocated for the new port and connections resumed without being
dropped.)
ifnet TLS can be enabled and disabled on supported network interfaces
via new '[-]txtls[46]' options to ifconfig(8). ifnet TLS is supported
across both vlan devices and lagg interfaces using failover, lacp with
flowid enabled, or lacp with flowid enabled.
Applications may request the current KTLS mode of a connection via a
new TCP_TXTLS_MODE socket option. They can also use this socket
option to toggle between software and ifnet TLS modes.
In addition, a testing tool is available in tools/tools/switch_tls.
This is modeled on tcpdrop and uses similar syntax. However, instead
of dropping connections, -s is used to force KTLS connections to
switch to software TLS and -i is used to switch to ifnet TLS.
Various sysctls and counters are available under the kern.ipc.tls
sysctl node. The kern.ipc.tls.enable node must be set to true to
enable KTLS (it is off by default). The use of unmapped mbufs must
also be enabled via kern.ipc.mb_use_ext_pgs to enable KTLS.
KTLS is enabled via the KERN_TLS kernel option.
This patch is the culmination of years of work by several folks
including Scott Long and Randall Stewart for the original design and
implementation; Drew Gallatin for several optimizations including the
use of ext_pgs mbufs, the M_NOTREADY mechanism for TLS records
awaiting software encryption, and pluggable software crypto backends;
and John Baldwin for modifications to support hardware TLS offload.
Reviewed by: gallatin, hselasky, rrs
Obtained from: Netflix
Sponsored by: Netflix, Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D21277
an retransmission of the initial SYN (with data) would
cause us to strip the SYN and decrement/increase offset/len
which then caused us a -1 offset and a panic.
Reported by: Larry Rosenman
(Michael Tuexen helped me debug this at the IETF)
When compiling RACK on platforms using gcc, a warning that tcp_outflags
is defined but not used is issued and terminates compilation on PPC64,
for example. So don't indicate that tcp_outflags is used.
Reviewed by: rrs@
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D20971
get BBRv1 into the tree. This fixes the DSACK bug but
is also needed by BBR. We have yet to go two more
one will be for the pacing code (tcp_ratelimit.c) and
the second will be for the new updated LRO code that
allows a transport to know the arrival times of packets
and (tcp_lro.c). After that we should finally be able
to get BBRv1 into head.
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D20908
well as sets in some of the groundwork for committing BBR. The
hpts system is updated as well as some other needed utilities
for the entrance of BBR. This is actually part 1 of 3 more
needed commits which will finally complete with BBRv1 being
added as a new tcp stack.
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D20834
in response to SACKs. The default behavior is unchanged; however, the limit
can be activated by changing the new net.inet.tcp.rack.split_limit sysctl.
Submitted by: Peter Lei <peterlei@netflix.com>
Reported by: jtl
Reviewed by: lstewart (earlier version)
Security: CVE-2019-5599
The corresponding changes for the RACK stack where missed and are added
by this commit.
Reviewed by: Richard Scheffenegger, rrs@
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D20372
Use recent best practices for Copyright form at the top of
the license:
1. Remove all the All Rights Reserved clauses on our stuff. Where we
piggybacked others, use a separate line to make things clear.
2. Use "Netflix, Inc." everywhere.
3. Use a single line for the copyright for grep friendliness.
4. Use date ranges in all places for our stuff.
Approved by: Netflix Legal (who gave me the form), adrian@ (pmc files)
consistently.
This inconsistency was observed when working on the bug reported in
PR 235256, although it does not fix the reported issue. The fix for
the PR will be a separate commit.
PR: 235256
Reviewed by: rrs@, Richard Scheffenegger
MFC after: 3 days
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D19033
RFC 3168 defines an ECN-setup SYN-ACK packet as on with the ECE flags
set and the CWR flags not set. The code was only checking if ECE flag
is set. This patch adds the check to verify that the CWR flags is not
set.
Submitted by: Richard Scheffenegger
Reviewed by: tuexen@
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D18996
When implementing support for IW10, an update in the computation
of the restart window used after an idle phase was missed. To
minimize code duplication, implement the logic in tcp_compute_initwnd()
and call it. This fixes a bug in NewReno, which was not aware of
IW10.
Submitted by: Richard Scheffenegger
Reviewed by: tuexen@
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D18940
segment in the SYN-SENT state as stated in Section 3.9 of RFC 793,
page 66. Ensure this is also done by the TCP RACK stack.
Reviewed by: rrs@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D18034
the TCP connection was initiated using the RACK stack, but the
peer does not support the TCP RACK extension.
This ensures that the TCP behaviour on the wire is the same if
the TCP connection is initated using the RACK stack or the default
stack.
Reviewed by: rrs@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D18032
zero. This was already done when sending them via tcp_respond().
Reviewed by: rrs@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D17949
There are two locations where an always true comparison was made in
a KASSERT. Replace this by an appropriate check and use a consistent
panic message. Also use this code when checking a similar condition.
PR: 229664
Reviewed by: rrs@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D18021
* Fix a bug where the SYN handling during established state was
applied to a front state.
* Move a check for retransmission after the timer handling.
This was suppressing timer based retransmissions.
* Fix an off-by one byte in the sequence number of retransmissions.
* Apply fixes corresponding to
https://svnweb.freebsd.org/changeset/base/336934
Reviewed by: rrs@
Approved by: re (kib@)
MFC after: 1 month
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D16912
reassembly inbound tcp segments. The old algorithm just blindly
dropped in segments without coalescing. This meant that every
segment could take up greater and greater room on the linked list
of segments. This of course is now subject to a tighter limit (100)
of segments which in a high BDP situation will cause us to be a
lot more in-efficent as we drop segments beyond 100 entries that
we receive. What this restructure does is cause the reassembly
buffer to coalesce segments putting an emphasis on the two
common cases (which avoid walking the list of segments) i.e.
where we add to the back of the queue of segments and where we
add to the front. We also have the reassembly buffer supporting
a couple of debug options (black box logging as well as counters
for code coverage). These are compiled out by default but can
be added by uncommenting the defines.
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D16626
sending an invalid segment into the reassembly
queue. This would happen if you enabled the
data after close option.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D16453
When a client receives a SYN-ACK segment with a TFP fast open cookie,
but without an MSS option, an MSS value from uninitialised stack memory is used.
This patch ensures that in case no MSS option is included in the SYN-ACK,
the appropriate value as given in RFC 7413 is used.
Reviewed by: kbowling@
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D16175
cache.
Without this patch, TCP FO could be used when using alternate
TCP stack, but only existing entires in the TCP client cookie
cache could be used. This cache was not populated by connections
using alternate TCP stacks.
Sponsored by: Netflix, Inc.
- Add tracker argument to preemptible epochs
- Inline epoch read path in kernel and tied modules
- Change in_epoch to take an epoch as argument
- Simplify tfb_tcp_do_segment to not take a ti_locked argument,
there's no longer any benefit to dropping the pcbinfo lock
and trying to do so just adds an error prone branchfest to
these functions
- Remove cases of same function recursion on the epoch as
recursing is no longer free.
- Remove the the TAILQ_ENTRY and epoch_section from struct
thread as the tracker field is now stack or heap allocated
as appropriate.
Tested by: pho and Limelight Networks
Reviewed by: kbowling at llnw dot com
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16066
- Convert inpcbinfo info & hash locks to epoch for read and mutex for write
- Garbage collect code that handled INP_INFO_TRY_RLOCK failures as
INP_INFO_RLOCK which can no longer fail
When running 64 netperfs sending minimal sized packets on a 2x8x2 reduces
unhalted core cycles samples in rwlock rlock/runlock in udp_send from 51% to
3%.
Overall packet throughput rate limited by CPU affinity and NIC driver design
choices.
On the receiver unhalted core cycles samples in in_pcblookup_hash went from
13% to to 1.6%
Tested by LLNW and pho@
Reviewed by: jtl
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D15686
Rack with respect to its handling of TCP Fast Open. Several
fixes all related to TFO are included in this commit:
1) Handling of non-TFO retransmissions
2) Building the proper send-map when we are doing TFO
3) Dealing with the ack that comes back that includes the
SYN and data.
It appears that with this commit TFO now works :-)
Thanks Larry for all your help!!
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D15758
time dependency.
At present, RACK requires the TCPHPTS option to run. However, because
modules can be moved from machine to machine, this dependency is really
best assessed at load time rather than at build time.
Reviewed by: rrs
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D15756
Rack includes the following features:
- A different SACK processing scheme (the old sack structures are not used).
- RACK (Recent acknowledgment) where counting dup-acks is no longer done
instead time is used to knwo when to retransmit. (see the I-D)
- TLP (Tail Loss Probe) where we will probe for tail-losses to attempt
to try not to take a retransmit time-out. (see the I-D)
- Burst mitigation using TCPHTPS
- PRR (partial rate reduction) see the RFC.
Once built into your kernel, you can select this stack by either
socket option with the name of the stack is "rack" or by setting
the global sysctl so the default is rack.
Note that any connection that does not support SACK will be kicked
back to the "default" base FreeBSD stack (currently known as "default").
To build this into your kernel you will need to enable in your
kernel:
makeoptions WITH_EXTRA_TCP_STACKS=1
options TCPHPTS
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D15525
It is the forerunner/foundational work of bringing in both Rack and BBR
which use hpts for pacing out packets. The feature is optional and requires
the TCPHPTS option to be enabled before the feature will be active. TCP
modules that use it must assure that the base component is compile in
the kernel in which they are loaded.
MFC after: Never
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D15020
can use them. Gather all TCP tunables in tcp_var.h in one place and
alphabetically sort them, to ease maintainance of the list.
Don't copy and paste declarations in tcp_stacks/fastpath.c.
This was discussed between various transport@ members and it was
requested to be reverted and discussed.
Submitted by: Kevin Bowling <kevin.bowling@kev009.com>
Reported by: lawrence
Reviewed by: hiren
Sponsored by: Limelight Networks
validation of SEG.ACK as the first step. If the ACK is not acceptable,
a RST segment should be sent and the segment should be dropped.
Up to now, the segment was partially processed.
This patch moves the check for the SEG.ACK validation up to the front
as required.
Reviewed by: hiren, gnn
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D10424
for example not in SYN-SENT.
This patch adds code to check the sysctl variable in other states than
LISTEN.
Thanks to ae and gnn for providing comments.
Reviewed by: gnn
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D9894
Switched from using timestamps to RTT estimates when performing TCP receive
buffer auto resizing, as not all hosts support / enable TCP timestamps.
Disabled reset of receive buffer auto scaling when not in bulk receive mode,
which gives an extra 20% performance increase.
Also extracted auto resizing to a common method shared between standard and
fastpath modules.
With this AWS S3 downloads at ~17ms latency on a 1Gbps connection jump from
~3MB/s to ~100MB/s using the default settings.
Reviewed by: lstewart, gnn
MFC after: 2 weeks
Relnotes: Yes
Sponsored by: Multiplay
Differential Revision: https://reviews.freebsd.org/D9668
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
