Sweep over potentially unsafe calls to ifnet_byindex() and wrap them
in epoch. Most of the code touched remains unsafe, as the returned
pointer is being used after epoch exit. Mark that with a comment.
Validate the index argument inside the function, reducing argument
validation requirement from the callers and making V_if_index
private to if.c.
Reviewed by: melifaro
Differential revision: https://reviews.freebsd.org/D33263
When rack sends out a TLP it sets up various state to make sure
it avoids the cwnd (its been more than 1 RTT since our last send) and
it may at times send new data. If an MTU change as occurred
and our cwnd has collapsed we can have a situation where must_retran
flag is set and we obey the cwnd thus never sending the TLP and then
sitting stuck.
This one line fix addresses that problem
Reviewed by: Michael Tuexen
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D33231
inpcb lookups, which check inp_cred, work with pcbs that potentially went
through in_pcbfree(). So inp_cred should stay valid until SMR guarantees
its invisibility to lookups.
While here, put the whole inpcb destruction sequence of in_pcbfree(),
inpcb_dtor() and inpcb_fini() sequentially.
Submitted by: markj
Differential revision: https://reviews.freebsd.org/D33273
The check to see if TCP port allocation should change from random to
sequential port allocation mode may incorrectly cause a false positive
due to negative wraparound.
Example:
V_ipport_tcpallocs = 2147483585 (0x7fffffc1)
V_ipport_tcplastcount = 2147483553 (0x7fffffa1)
V_ipport_randomcps = 100
The original code would compare (2147483585 <= -2147483643) and thus
incorrectly move to sequential allocation mode.
Compute the delta first before comparing against the desired limit to
limit the wraparound effect (since tcplastcount is always a snapshot
of a previous tcpallocs).
When sending packets the stcb was used to access the inp and then
access the endpoint specific IPv6 level options. This fails when
there exists an inp, but no stcb yet. This is the case for sending
an INIT-ACK in response to an INIT when no association already
exists. Fix this by just providing the inp instead of the stcb.
PR: 260120
MFC after: 1 week
Fix logic error causing UDP(-Lite) local ephemeral port bindings
to count against the TCP allocation counter, potentially causing
TCP to go from random to sequential port allocation mode prematurely.
This reverts commit 266f97b5e9, reversing
changes made to a10253cffe.
A mismerge of a merge to catch up to main resulted in files being
committed which should not have been.
Just trust the pcb database, that if we did in_pcbref(), no way
an inpcb can go away. And if we never put a dropped inpcb on
our queue, and tcp_discardcb() always removes an inpcb to be
dropped from the queue, then any inpcb on the queue is valid.
Now, to solve LOR between inpcb lock and HPTS queue lock do the
following trick. When we are about to process a certain time
slot, take the full queue of the head list into on stack list,
drop the HPTS lock and work on our queue. This of course opens
a race when an inpcb is being removed from the on stack queue,
which was already mentioned in comments. To address this race
introduce generation count into queues. If we want to remove
an inpcb with generation count mismatch, we can't do that, we
can only mark it with desired new time slot or -1 for remove.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D33026
The HPTS input queue is in reality used only for "delayed drops".
When a TCP stack decides to drop a connection on the output path
it can't do that due to locking protocol between main tcp_output()
and stacks. So, rack/bbr utilize HPTS to drop the connection in
a different context.
In the past the queue could also process input packets in context
of HPTS thread, but now no stack uses this, so remove this
functionality.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D33025
Also, make some of the functions also private to the module. Remove
unused functions discovered after that.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D33024
With introduction of epoch(9) synchronization to network stack the
inpcb database became protected by the network epoch together with
static network data (interfaces, addresses, etc). However, inpcb
aren't static in nature, they are created and destroyed all the
time, which creates some traffic on the epoch(9) garbage collector.
Fairly new feature of uma(9) - Safe Memory Reclamation allows to
safely free memory in page-sized batches, with virtually zero
overhead compared to uma_zfree(). However, unlike epoch(9), it
puts stricter requirement on the access to the protected memory,
needing the critical(9) section to access it. Details:
- The database is already build on CK lists, thanks to epoch(9).
- For write access nothing is changed.
- For a lookup in the database SMR section is now required.
Once the desired inpcb is found we need to transition from SMR
section to r/w lock on the inpcb itself, with a check that inpcb
isn't yet freed. This requires some compexity, since SMR section
itself is a critical(9) section. The complexity is hidden from
KPI users in inp_smr_lock().
- For a inpcb list traversal (a pcblist sysctl, or broadcast
notification) also a new KPI is provided, that hides internals of
the database - inp_next(struct inp_iterator *).
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D33022
With upcoming changes to the inpcb synchronisation it is going to be
broken. Even its current status after the move of PCB synchronization
to the network epoch is very questionable.
This experimental feature was sponsored by Juniper but ended never to
be used in Juniper and doesn't exist in their source tree [sjg@, stevek@,
jtl@]. In the past (AFAIK, pre-epoch times) it was tried out at Netflix
[gallatin@, rrs@] with no positive result and at Yandex [ae@, melifaro@].
I'm up to resurrecting it back if there is any interest from anybody.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D33020
I just discovered that the return of the EBUSY error was incorrectly
rigged so that you could unload a CC module that was set to default.
Its supposed to be an EBUSY error. Make it so.
Reviewed by: Michael Tuexen
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D33229
For socket options related to local and remote addresses providing
generic association ids does not make sense. Report EINVAL in this
case.
MFC after: 1 week
This allows it to work with unmapped mbufs. In particular,
in_cksum_skip() calls no longer need to be preceded by calls to
mb_unmapped_to_ext() to avoid a page fault.
PR: 259645
Reviewed by: gallatin, glebius, jhb
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33096
in_cksum() and related routines are implemented separately for each
platform, but only i386 and arm have optimized versions. Other
platforms' copies of in_cksum.c are identical except for style
differences and support for big-endian CPUs.
Deduplicate the implementations for the rest of the platforms. This
will make it easier to implement in_cksum() for unmapped mbufs. On arm
and i386, define HAVE_MD_IN_CKSUM to mean that the MI implementation is
not to be compiled.
No functional change intended.
Reviewed by: kp, glebius
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33095
It does not get compiled into the kernel. No functional change
inteneded.
Reviewed by: kp, glebius, cy
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33094
Until this change there were two places where we would free tcpcb -
tcp_discardcb() in case if all timers are drained and tcp_timer_discard()
otherwise. They were pretty much copy-n-paste, except that in the
default case we would run tcp_hc_update(). Merge this into single
function tcp_freecb() and move new short version of tcp_timer_discard()
to tcp_timer.c and make it static.
Reviewed by: rrs, hselasky
Differential revision: https://reviews.freebsd.org/D32965
In case we failed to uma_zalloc() and also failed to reuse with
tcp_tw_2msl_scan(), then just use on stack tcptw. This will allow
to run through tcp_twrespond() and standard tcpcb discard routine.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D32965
Previously we added ack-war prevention for misbehaving firewalls. This is
where the f/w or nat messes up its sequence numbers and causes an ack-war.
There is yet another type of ack war that we have found in the wild that is
like unto this. Basically the f/w or nat gets a ack (keep-alive probe or such)
and instead of turning the ack/seq around and adding a TH_RST it does something
real stupid and sends a new packet with seq=0. This of course triggers the challenge
ack in the reset processing which then sends in a challenge ack (if the seq=0 is within
the range of possible sequence numbers allowed by the challenge) and then we rinse-repeat.
This will add the needed tweaks (similar to the last ack-war prevention using the same sysctls and counters)
to prevent it and allow say 5 per second by default.
Reviewed by: Michael Tuexen
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D32938
m_apply() works on unmapped mbufs, so this will let us elide
mb_unmapped_to_ext() calls preceding sctp_calculate_cksum() calls in
the network stack.
Modify sctp_calculate_cksum() to assume it's passed an mbuf header.
This assumption appears to be true in practice, and we need to know the
full length of the chain.
No functional change intended.
Reviewed by: tuexen, jhb
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32941
When no mask is supplied to the ioctl adding an Internet interface
address, revert to using the historical class mask rather than a
single default. Similarly for the NFS bootp code.
MFC after: 3 weeks
Reviewed by: melifaro glebius
Differential Revision: https://reviews.freebsd.org/D32951
The code was probably useful during the problem being chased down,
but for brevity makes sense just to return to the original KASSERT.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D32968
All timers keep inpcb locked through their execution. We need to
check these flags only once. Checking for INP_TIMEWAIT earlier is
is also safer, since such inpcbs point into tcptw rather than tcpcb,
and any dereferences of inp_ppcb as tcpcb are erroneous.
Reviewed by: rrs, hselasky
Differential revision: https://reviews.freebsd.org/D32967
This causes new vnets to inherit the cc algorithm from vnet0. This is a
temporary patch to fix vnet jail creation.
With encouragement from: glebius
Fixes: b8d60729de ("tcp: Congestion control cleanup.")
Differential Revision: https://reviews.freebsd.org/D32970
Define CC_NEWRENO in all the appropriate DEFAULTS and std.* config
files. It's the default congestion control algorithm. Add code to cc.c
so that CC_DEFAULT is "newreno" if it's not overriden in the config
file.
Sponsored by: Netflix
Fixes: b8d60729de ("tcp: Congestion control cleanup.")
Revired by: manu, hselasky, jhb, glebius, tuexen
Differential Revision: https://reviews.freebsd.org/D32964
Drop packets arriving from the network that have our source IP
address. If maliciously crafted they can create evil effects
like an RST exchange between two of our listening TCP ports.
Such packets just can't be legitimate. Enable the tunable
by default. Long time due for a modern Internet host.
Reviewed by: donner, melifaro
Differential revision: https://reviews.freebsd.org/D32914
