Stop further processing of a packet when detecting that it
contains an INIT chunk, which is too small or is not the only
chunk in the packet. Still allow to finish the processing
of chunks before the INIT chunk.
Thanks to Antoly Korniltsev and Taylor Brandstetter for reporting
an issue with the userland stack, which made me aware of this
issue.
MFC after: 3 days
structure is zeroed, by setting the VNET after checking the mbuf count
for zero. It appears there are some cases with early interrupts on some
network devices which still trigger page-faults on accessing a NULL "ifp"
pointer before the TCP LRO control structure has been initialized.
This basically preserves the old behaviour, prior to
9ca874cf74 .
No functional change.
Reported by: rscheff@
Differential Revision: https://reviews.freebsd.org/D29564
MFC after: 2 weeks
Sponsored by: Mellanox Technologies // NVIDIA Networking
This reverts a portion of 274579831b ("capsicum: Limit socket
operations in capability mode") as at least rtsol and dhcpcd rely on
being able to configure network interfaces while in capability mode.
Reported by: bapt, Greg V
Sponsored by: The FreeBSD Foundation
Notify the TOE driver when when an ICMP type 3 code 4 (Fragmentation
needed and DF set) message is received for an offloaded connection.
This gives the driver an opportunity to lower the path MTU for the
connection and resume transmission, much like what the kernel does for
the connections that it handles.
Reviewed by: glebius@
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D29755
Also add an M_ASSERTMAPPED() macro to verify that all mbufs in the chain
are mapped. Use it in ipfw_nat, which operates on a chain returned by
m_megapullup().
PR: 255164
Reviewed by: ae, gallatin
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29838
In certain cases, e.g. a SYN-flood from a limited set of hosts,
the TCP hostcache becomes the main contention point. To solve
that, this change introduces lockless lookups on the hostcache.
The cache remains a hash, however buckets are now CK_SLIST. For
updates a bucket mutex is obtained, for read an SMR section is
entered.
Reviewed by: markj, rscheff
Differential revision: https://reviews.freebsd.org/D29729
This is further rework of 08d9c92027. Now we carry the knowledge of
lock type all the way through tcp_input() and also into tcp_twcheck().
Ideally the rlocking for pure SYNs should propagate all the way into
the alternative TCP stacks, but not yet today.
This should close a race when socket is bind(2)-ed but not yet
listen(2)-ed and a SYN-packet arrives racing with listen(2), discovered
recently by pho@.
When a rescue retransmission is successful, rather than
inserting new holes to the left of it, adjust the old
rescue entry to cover the missed sequence space.
Also, as snd_fack may be stale by that point, pull it forward
in order to never create a hole left of snd_una/th_ack.
Finally, with DSACKs, tcp_sack_doack() may be called
with new full ACKs but a DSACK block. Account for this
eventuality properly to keep sacked_bytes >= 0.
MFC after: 3 days
Reviewed By: kbowling, tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29835
This change makes the TCP LRO code more generic and flexible with regards
to supporting multiple different TCP encapsulation protocols and in general
lays the ground for broader TCP LRO support. The main job of the TCP LRO code is
to merge TCP packets for the same flow, to reduce the number of calls to upper
layers. This reduces CPU and increases performance, due to being able to send
larger TSO offloaded data chunks at a time. Basically the TCP LRO makes it
possible to avoid per-packet interaction by the host CPU.
Because the current TCP LRO code was tightly bound and optimized for TCP/IP
over ethernet only, several larger changes were needed. Also a minor bug was
fixed in the flushing mechanism for inactive entries, where the expire time,
"le->mtime" was not always properly set.
To avoid having to re-run time consuming regression tests for every change,
it was chosen to squash the following list of changes into a single commit:
- Refactor parsing of all address information into the "lro_parser" structure.
This easily allows to reuse parsing code for inner headers.
- Speedup header data comparison. Don't compare field by field, but
instead use an unsigned long array, where the fields get packed.
- Refactor the IPv4/TCP/UDP checksum computations, so that they may be computed
recursivly, only applying deltas as the result of updating payload data.
- Make smaller inline functions doing one operation at a time instead of
big functions having repeated code.
- Refactor the TCP ACK compression code to only execute once
per TCP LRO flush. This gives a minor performance improvement and
keeps the code simple.
- Use sbintime() for all time-keeping. This change also fixes flushing
of inactive entries.
- Try to shrink the size of the LRO entry, because it is frequently zeroed.
- Removed unused TCP LRO macros.
- Cleanup unused TCP LRO statistics counters while at it.
- Try to use __predict_true() and predict_false() to optimise CPU branch
predictions.
Bump the __FreeBSD_version due to changing the "lro_ctrl" structure.
Tested by: Netflix
Reviewed by: rrs (transport)
Differential Revision: https://reviews.freebsd.org/D29564
MFC after: 2 week
Sponsored by: Mellanox Technologies // NVIDIA Networking
Adding support for TCP over UDP allows communication with
TCP stacks which can be implemented in userspace without
requiring special priviledges or specific support by the OS.
This is joint work with rrs.
Reviewed by: rrs
Sponsored by: Netflix, Inc.
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29469
Maintain code similarity between RACK and base stack
for ECN. This may not strictly be necessary, depending
when a state transition to FIN_WAIT_1 is done in RACK
after a shutdown() or close() syscall.
MFC after: 3 days
Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29658
As full support of RFC6675 is in place, deprecating
net.inet.tcp.rfc6675_pipe and enabling by default
net.inet.tcp.sack.revised.
Reviewed By: #transport, kbowling, rrs
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D28702
A security feature from c06f087ccb appeared to be a huge bottleneck
under SYN flood. To mitigate that add a sysctl that would make
syncache(4) globally visible, ignoring UID/GID, jail(2) and mac(4)
checks. When turned on, we won't need to call crhold() on the listening
socket credential for every incoming SYN packet.
Reviewed by: bz
When packet is a SYN packet, we don't need to modify any existing PCB.
Normally SYN arrives on a listening socket, we either create a syncache
entry or generate syncookie, but we don't modify anything with the
listening socket or associated PCB. Thus create a new PCB lookup
mode - rlock if listening. This removes the primary contention point
under SYN flood - the listening socket PCB.
Sidenote: when SYN arrives on a synchronized connection, we still
don't need write access to PCB to send a challenge ACK or just to
drop. There is only one exclusion - tcptw recycling. However,
existing entanglement of tcp_input + stacks doesn't allow to make
this change small. Consider this patch as first approach to the problem.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D29576
inp_lookup_mcast_ifp() is static and is only used in the inp_join_group().
The latter function is also static, and is only used in the inp_setmoptions(),
which relies on inp being non-NULL.
As a result, in the current code, inp_lookup_mcast_ifp() is always called
with non-NULL inp. Eliminate unused RT_DEFAULT_FIB condition and always
use inp fib instead.
Differential Revision: https://reviews.freebsd.org/D29594
Reviewed by: kp
MFC after: 2 weeks
As other parts of the base tcp stack (eg.
tcp fastopen) already use jenkins_hash32,
and the properties appear reasonably good,
switching to use that.
Reviewed By: tuexen, #transport, ae
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29515
looking to only read from the result, or to update it as well.
For now doesn't affect locking, but allows to push stats and expire
update into single place.
Reviewed by: rscheff
Add proper PRR vnet declarations for consistency.
Also add pointer to tcpopt struct to tcp_do_prr_ack, in preparation
for it to deal with non-SACK window reduction (after loss).
No functional change.
MFC after: 2 weeks
Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29440
A subtle oversight would subtly change new data packets
sent after a shutdown() or close() call, while the send
buffer is still draining.
MFC after: 3 days
Reviewed By: #transport, tuexen
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29616
Capsicum did not prevent certain privileged networking operations,
specifically creation of raw sockets and network configuration ioctls.
However, these facilities can be used to circumvent some of the
restrictions that capability mode is supposed to enforce.
Add capability mode checks to disallow network configuration ioctls and
creation of sockets other than PF_LOCAL and SOCK_DGRAM/STREAM/SEQPACKET
internet sockets.
Reviewed by: oshogbo
Discussed with: emaste
Reported by: manu
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D29423
After making sbuf_drain safe for external use,
there is no need to protect the call.
MFC after: 2 weeks
Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29545
Provide a histogram output to check, if the hashsize or
bucketlimit could be optimized. Also add some basic sanity
checks around the accounting of the hash utilization.
MFC after: 2 weeks
Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29506
As accessing the tcp hostcache happens frequently on some
classes of servers, it was recommended to use atomic_add/subtract
rather than (per-CPU distributed) counters, which have to be
summed up at high cost to cache efficiency.
PR: 254333
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Reviewed By: #transport, tuexen, jtl
Differential Revision: https://reviews.freebsd.org/D29522
Addressing the underlying root cause for cache_count to
show unexpectedly high values, by protecting all arithmetic on
that global variable by using counter(9).
PR: 254333
Reviewed By: tuexen, #transport
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29510
Explicitly drain the sbuf after completing each hash bucket
to minimize the work performed while holding the hash
bucket lock.
PR: 254333
MFC after: 2 weeks
Reviewed By: tuexen, jhb, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29483
We are inspecting PCBs of divert sockets under NET_EPOCH section,
but PCB could be already detached and we should check INP_FREED flag
when we took INP_RLOCK.
PR: 254478
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29420
In tcp_hostcache_list, the sbuf used would need a large (~2MB)
blocking allocation of memory (M_WAITOK), when listing a
full hostcache. This may stall the requestor for an indeterminate
time.
A further optimization is to return the expected userspace
buffersize right away, rather than preparing the output of
each current entry of the hostcase, provided by: @tuexen.
This makes use of the ready-made functions of sbuf to work
with sysctl, and repeatedly drain the much smaller buffer.
PR: 254333
MFC after: 2 weeks
Reviewed By: #transport, tuexen
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29471
Ensure that the stack does not generate a DSACK block for user
data received on a SYN segment in SYN-SENT state.
Reviewed by: rscheff
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D29376
Sponsored by: Netflix, Inc.
