When epoch(9) was introduced to network stack, it was basically
dropped in place of existing locking, which was mutexes and
rwlocks. For the sake of performance mutex covered areas were
as small as possible, so became epoch covered areas.
However, epoch doesn't introduce any contention, it just delays
memory reclaim. So, there is no point to minimise epoch covered
areas in sense of performance. Meanwhile entering/exiting epoch
also has non-zero CPU usage, so doing this less often is a win.
Not the least is also code maintainability. In the new paradigm
we can assume that at any stage of processing a packet, we are
inside network epoch. This makes coding both input and output
path way easier.
On output path we already enter epoch quite early - in the
ip_output(), in the ip6_output().
This patch does the same for the input path. All ISR processing,
network related callouts, other ways of packet injection to the
network stack shall be performed in net_epoch. Any leaf function
that walks network configuration now asserts epoch.
Tricky part is configuration code paths - ioctls, sysctls. They
also call into leaf functions, so some need to be changed.
This patch would introduce more epoch recursions (see EPOCH_TRACE)
than we had before. They will be cleaned up separately, as several
of them aren't trivial. Note, that unlike a lock recursion the
epoch recursion is safe and just wastes a bit of resources.
Reviewed by: gallatin, hselasky, cy, adrian, kristof
Differential Revision: https://reviews.freebsd.org/D19111
The new sysctl was not added to the siftr.4 man page at the time.
This updates the man page, and removes one left over trailing whitespace.
Submitted by: Richard Scheffenegger
Reviewed by: bcr@
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D21619
no longer worked. The problem was that the defines used the
same space as the VLAN id. This commit does three things.
1) Move the LRO used fields to the PH_per fields. This is
safe since the entire PH_per is used for IP reassembly
which LRO code will not hit.
2) Remove old unused pace fields that are not used in mbuf.h
3) The VLAN processing is not in the mbuf queueing code. Consequently
if a VLAN submits to Rack or BBR we need to bypass the mbuf queueing
for now until rack_bbr_common is updated to handle the VLAN properly.
Reported by: Brad Davis
that this path is taken by setting the tail pointer correctly.
There is still bug related to handling unordered unfragmented messages
which were delayed in deferred handling.
This issue was found by OSS-Fuzz testing the usrsctp stack and reported in
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=17794
MFC after: 3 days
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
initialisation, which is important when the host is dealing with a
SYN flood.
This affects the computation of the initial TCP sequence number for
the client side.
This has been discussed with secteam@.
Reviewed by: gallatin@
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21616
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
syn cache overflows. Whether this is due to an attack or due to the system
having more legitimate connections than the syn cache can hold, this
situation can quickly impact performance.
To make the system perform better during these periods, the code will now
switch to exclusively using cookies until the syn cache stops overflowing.
In order for this to occur, the system must be configured to use the syn
cache with syn cookie fallback. If syn cookies are completely disabled,
this change should have no functional impact.
When the system is exclusively using syn cookies (either due to
configuration or the overflow detection enabled by this change), the
code will now skip acquiring a lock on the syn cache bucket. Additionally,
the code will now skip lookups in several places (such as when the system
receives a RST in response to a SYN|ACK frame).
Reviewed by: rrs, gallatin (previous version)
Discussed with: tuexen
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21644
rather than indirectly through the backpointer to the tcp_syncache
structure stored in the hashtable bucket.
This also allows us to remove the requirement in syncookie_generate()
and syncookie_lookup() that the syncache hashtable bucket must be
locked.
Reviewed by: gallatin, rrs
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21644
use of this parameter was removed in r313330. This commit now removes
passing this now-unused parameter.
Reviewed by: gallatin, rrs
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D21644
that instead of functions only being inside the _KERNEL and
the absence of RATELIMIT causing us to have NULL/error returning
interfaces we ended up with non-kernel getting the error path.
opps..
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
This avoids a double lock bug in the NAT colliding state processing
of SCTP. Thanks to Felix Weinrank for finding and reporting this issue in
https://github.com/sctplab/usrsctp/issues/374
He found this bug using fuzz testing.
MFC after: 3 days
before computing the RTO.
This should fix an overflow issue reported by Felix Weinrank in
https://github.com/sctplab/usrsctp/issues/375
for the userland stack and found by running a fuzz tester.
MFC after: 3 days
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
checksum computation, do not assume that the IP header chain and the
SCTP common header are in contiguous memory although the SCTP lays
out the mbuf chains that way. If there are IP-level options inserted
by the IP layer, the constraint is not fulfilled anymore.
This issues was found by running syzkaller. Thanks to markj@ who is
running an instance which also provides kernel dumps. This allowed me
to find this issue.
MFC after: 3 days
Don't call arc4random() unconditionally to initialize sc_iss, and
then when syncookies are enabled, just overwrite it with the
return value from from syncookie_generate(). Instead, only call
arc4random() to initialize sc_iss when syncookies are not
enabled.
Note that on a system under a syn flood attack, arc4random()
becomes quite expensive, and the chacha_poly crypto that it calls
is one of the more expensive things happening on the
system. Removing this unneeded arc4random() call reduces CPU from
about 40% to about 35% in my test scenario (Broadwell Xeon, 6Mpps
syn flood attack).
Reviewed by: rrs, tuxen, bz
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21591
sb_tls_flags, its just the sb_flags. Also the ratelimit
code, now that the defintion is in sockbuf.h, does not
need the ktls.h file (or its predecessor).
Sponsored by: Netflix Inc
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
This fixes problem with parameters indicating a zero length or partial
parameters after an unknown parameter indicating to stop processing. It
also fixes a problem with state cookie parameters after unknown
parametes indicating to stop porcessing.
Thanks to Mark Wodrich from Google for finding two of these issues
by fuzz testing the userland stack and reporting them in
https://github.com/sctplab/usrsctp/issues/355
and
https://github.com/sctplab/usrsctp/issues/352
MFC after: 3 days
data chunks. Abort the association if there are data chunks with larger
fragement sequence numbers than the fragement sequence of the last
fragment.
Thanks to Mark Wodrich from Google who found this issue by fuzz testing
the userland stack and reporting this issue in
https://github.com/sctplab/usrsctp/issues/355
MFC after: 3 days
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)
nd_buf is used to buffer headers (for both the kernel dump itself and
for EKCD) before the final call to netdump_dumper(), which flushes
residual data in nd_buf. As a result, a small portion of the residual
data would be corrupted. This manifests when kernel dump compression
is enabled since both zstd and zlib detect the corruption during
decompression.
Reviewed by: cem
Differential Revision: https://reviews.freebsd.org/D21294
Since ipvoly is used for checksum calculation, part of original IP
header is zeroed. This part includes ip_ttl field, that can be used
later in IP_MINTTL socket option handling.
PR: 239799
MFC after: 1 week
