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  1. 28 4月, 2018 2 次提交
  3. 09 1月, 2018 1 次提交
    • M
      sctp: fix the handling of ICMP Frag Needed for too small MTUs · b6c5734d
      由 Marcelo Ricardo Leitner 提交于 
      syzbot reported a hang involving SCTP, on which it kept flooding dmesg
with the message:
[  246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512

That happened because whenever SCTP hits an ICMP Frag Needed, it tries
to adjust to the new MTU and triggers an immediate retransmission. But
it didn't consider the fact that MTUs smaller than the SCTP minimum MTU
allowed (512) would not cause the PMTU to change, and issued the
retransmission anyway (thus leading to another ICMP Frag Needed, and so
on).

As IPv4 (ip_rt_min_pmtu=556) and IPv6 (IPV6_MIN_MTU=1280) minimum MTU
are higher than that, sctp_transport_update_pmtu() is changed to
re-fetch the PMTU that got set after our request, and with that, detect
if there was an actual change or not.

The fix, thus, skips the immediate retransmission if the received ICMP
resulted in no change, in the hope that SCTP will select another path.

Note: The value being used for the minimum MTU (512,
SCTP_DEFAULT_MINSEGMENT) is not right and instead it should be (576,
SCTP_MIN_PMTU), but such change belongs to another patch.

Changes from v1:
- do not disable PMTU discovery, in the light of commit
06ad3919 ("[SCTP] Don't disable PMTU discovery when mtu is small")
and as suggested by Xin Long.
- changed the way to break the rtx loop by detecting if the icmp
  resulted in a change or not
Changes from v2:
none

See-also: https://lkml.org/lkml/2017/12/22/811Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b6c5734d
  5. 25 10月, 2017 1 次提交
  7. 07 8月, 2017 1 次提交
  9. 05 7月, 2017 1 次提交
  11. 26 6月, 2017 4 次提交
  13. 05 4月, 2017 1 次提交
  15. 28 2月, 2017 1 次提交
  17. 08 2月, 2017 1 次提交
  19. 19 1月, 2017 1 次提交
    • X
      sctp: add stream reconf timer · 7b9438de
      由 Xin Long 提交于 
      This patch is to add a per transport timer based on sctp timer frame
for stream reconf chunk retransmission. It would start after sending
a reconf request chunk, and stop after receiving the response chunk.

If the timer expires, besides retransmitting the reconf request chunk,
it would also do the same thing with data RTO timer. like to increase
the appropriate error counts, and perform threshold management, possibly
destroying the asoc if sctp retransmission thresholds are exceeded, just
as section 5.1.1 describes.

This patch is also to add asoc strreset_chunk, it is used to save the
reconf request chunk, so that it can be retransmitted, and to check if
the response is really for this request by comparing the information
inside with the response chunk as well.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7b9438de
  21. 26 12月, 2016 1 次提交
    • T
      ktime: Cleanup ktime_set() usage · 8b0e1953
      由 Thomas Gleixner 提交于 
      ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
      8b0e1953
  23. 22 9月, 2016 1 次提交
  25. 11 4月, 2016 1 次提交
    • M
      sctp: avoid refreshing heartbeat timer too often · ba6f5e33
      由 Marcelo Ricardo Leitner 提交于 
      Currently on high rate SCTP streams the heartbeat timer refresh can
consume quite a lot of resources as timer updates are costly and it
contains a random factor, which a) is also costly and b) invalidates
mod_timer() optimization for not editing a timer to the same value.
It may even cause the timer to be slightly advanced, for no good reason.

As suggested by David Laight this patch now removes this timer update
from hot path by leaving the timer on and re-evaluating upon its
expiration if the heartbeat is still needed or not, similarly to what is
done for TCP. If it's not needed anymore the timer is re-scheduled to
the new timeout, considering the time already elapsed.

For this, we now record the last tx timestamp per transport, updated in
the same spots as hb timer was restarted on tx. Also split up
sctp_transport_reset_timers into sctp_transport_reset_t3_rtx and
sctp_transport_reset_hb_timer, so we can re-arm T3 without re-arming the
heartbeat one.

On loopback with MTU of 65535 and data chunks with 1636, so that we
have a considerable amount of chunks without stressing system calls,
netperf -t SCTP_STREAM -l 30, perf looked like this before:

Samples: 103K of event 'cpu-clock', Event count (approx.): 25833000000
  Overhead  Command  Shared Object      Symbol
+    6,15%  netperf  [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
-    5,43%  netperf  [kernel.vmlinux]   [k] _raw_write_unlock_irqrestore
   - _raw_write_unlock_irqrestore
      - 96,54% _raw_spin_unlock_irqrestore
         - 36,14% mod_timer
            + 97,24% sctp_transport_reset_timers
            + 2,76% sctp_do_sm
         + 33,65% __wake_up_sync_key
         + 28,77% sctp_ulpq_tail_event
         + 1,40% del_timer
      - 1,84% mod_timer
         + 99,03% sctp_transport_reset_timers
         + 0,97% sctp_do_sm
      + 1,50% sctp_ulpq_tail_event

And after this patch, now with netperf -l 60:

Samples: 230K of event 'cpu-clock', Event count (approx.): 57707250000
  Overhead  Command  Shared Object      Symbol
+    5,65%  netperf  [kernel.vmlinux]   [k] memcpy_erms
+    5,59%  netperf  [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
-    5,05%  netperf  [kernel.vmlinux]   [k] _raw_spin_unlock_irqrestore
   - _raw_spin_unlock_irqrestore
      + 49,89% __wake_up_sync_key
      + 45,68% sctp_ulpq_tail_event
      - 2,85% mod_timer
         + 76,51% sctp_transport_reset_t3_rtx
         + 23,49% sctp_do_sm
      + 1,55% del_timer
+    2,50%  netperf  [sctp]             [k] sctp_datamsg_from_user
+    2,26%  netperf  [sctp]             [k] sctp_sendmsg

Throughput-wise, from 6800mbps without the patch to 7050mbps with it,
~3.7%.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ba6f5e33
  27. 21 3月, 2016 1 次提交
    • M
      sctp: align MTU to a word · 3822a5ff
      由 Marcelo Ricardo Leitner 提交于 
      SCTP is a protocol that is aligned to a word (4 bytes). Thus using bare
MTU can sometimes return values that are not aligned, like for loopback,
which is 65536 but ipv4_mtu() limits that to 65535. This mis-alignment
will cause the last non-aligned bytes to never be used and can cause
issues with congestion control.

So it's better to just consider a lower MTU and keep congestion control
calcs saner as they are based on PMTU.

Same applies to icmp frag needed messages, which is also fixed by this
patch.

One other effect of this is the inability to send MTU-sized packet
without queueing or fragmentation and without hitting Nagle. As the
check performed at sctp_packet_can_append_data():

if (chunk->skb->len + q->out_qlen >= transport->pathmtu - packet->overhead)
	/* Enough data queued to fill a packet */
	return SCTP_XMIT_OK;

with the above example of MTU, if there are no other messages queued,
one cannot send a packet that just fits one packet (65532 bytes) and
without causing DATA chunk fragmentation or a delay.

v2:
 - Added WORD_TRUNC macro
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3822a5ff
  29. 14 3月, 2016 1 次提交
    • X
      sctp: fix the transports round robin issue when init is retransmitted · 39d2adeb
      由 Xin Long 提交于 
      prior to this patch, at the beginning if we have two paths in one assoc,
they may have the same params other than the last_time_heard, it will try
the paths like this:

1st cycle
  try trans1 fail.
  then trans2 is selected.(cause it's last_time_heard is after trans1).

2nd cycle:
  try  trans2 fail
  then trans2 is selected.(cause it's last_time_heard is after trans1).

3rd cycle:
  try  trans2 fail
  then trans2 is selected.(cause it's last_time_heard is after trans1).

....

trans1 will never have change to be selected, which is not what we expect.
we should keeping round robin all the paths if they are just added at the
beginning.

So at first every tranport's last_time_heard should be initialized 0, so
that we ensure they have the same value at the beginning, only by this,
all the transports could get equal chance to be selected.

Then for sctp_trans_elect_best, it should return the trans_next one when
*trans == *trans_next, so that we can try next if it fails,  but now it
always return trans. so we can fix it by exchanging these two params when
we calls sctp_trans_elect_tie().

Fixes: 4c47af4d ('net: sctp: rework multihoming retransmission path selection to rfc4960')
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      39d2adeb
  31. 29 1月, 2016 2 次提交
  33. 10 11月, 2015 1 次提交
    • A
      remove abs64() · 79211c8e
      由 Andrew Morton 提交于 
      Switch everything to the new and more capable implementation of abs().
Mainly to give the new abs() a bit of a workout.

Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      79211c8e
  35. 01 8月, 2014 1 次提交
    • J
      sctp: Fixup v4mapped behaviour to comply with Sock API · 299ee123
      由 Jason Gunthorpe 提交于 
      The SCTP socket extensions API document describes the v4mapping option as
follows:

8.1.15.  Set/Clear IPv4 Mapped Addresses (SCTP_I_WANT_MAPPED_V4_ADDR)

   This socket option is a Boolean flag which turns on or off the
   mapping of IPv4 addresses.  If this option is turned on, then IPv4
   addresses will be mapped to V6 representation.  If this option is
   turned off, then no mapping will be done of V4 addresses and a user
   will receive both PF_INET6 and PF_INET type addresses on the socket.
   See [RFC3542] for more details on mapped V6 addresses.

This description isn't really in line with what the code does though.

Introduce addr_to_user (renamed addr_v4map), which should be called
before any sockaddr is passed back to user space. The new function
places the sockaddr into the correct format depending on the
SCTP_I_WANT_MAPPED_V4_ADDR option.

Audit all places that touched v4mapped and either sanely construct
a v4 or v6 address then call addr_to_user, or drop the
unnecessary v4mapped check entirely.

Audit all places that call addr_to_user and verify they are on a sycall
return path.

Add a custom getname that formats the address properly.

Several bugs are addressed:
 - SCTP_I_WANT_MAPPED_V4_ADDR=0 often returned garbage for
   addresses to user space
 - The addr_len returned from recvmsg was not correct when
   returning AF_INET on a v6 socket
 - flowlabel and scope_id were not zerod when promoting
   a v4 to v6
 - Some syscalls like bind and connect behaved differently
   depending on v4mapped

Tested bind, getpeername, getsockname, connect, and recvmsg for proper
behaviour in v4mapped = 1 and 0 cases.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Tested-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      299ee123
  37. 03 7月, 2014 1 次提交
    • D
      net: sctp: improve timer slack calculation for transport HBs · 8f61059a
      由 Daniel Borkmann 提交于 
      RFC4960, section 8.3 says:

  On an idle destination address that is allowed to heartbeat,
  it is recommended that a HEARTBEAT chunk is sent once per RTO
  of that destination address plus the protocol parameter
  'HB.interval', with jittering of +/- 50% of the RTO value,
  and exponential backoff of the RTO if the previous HEARTBEAT
  is unanswered.

Currently, we calculate jitter via sctp_jitter() function first,
and then add its result to the current RTO for the new timeout:

  TMO = RTO + (RAND() % RTO) - (RTO / 2)
              `------------------------^-=> sctp_jitter()

Instead, we can just simplify all this by directly calculating:

  TMO = (RTO / 2) + (RAND() % RTO)

With the help of prandom_u32_max(), we don't need to open code
our own global PRNG, but can instead just make use of the per
CPU implementation of prandom with better quality numbers. Also,
we can now spare us the conditional for divide by zero check
since no div or mod operation needs to be used. Note that
prandom_u32_max() won't emit the same result as a mod operation,
but we really don't care here as we only want to have a random
number scaled into RTO interval.

Note, exponential RTO backoff is handeled elsewhere, namely in
sctp_do_8_2_transport_strike().
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      8f61059a
  39. 12 6月, 2014 1 次提交
  41. 14 2月, 2014 1 次提交
  43. 07 12月, 2013 1 次提交
  45. 06 12月, 2013 1 次提交
  47. 13 8月, 2013 1 次提交
  49. 10 8月, 2013 1 次提交
  51. 25 7月, 2013 1 次提交
  53. 02 7月, 2013 1 次提交
    • D
      net: sctp: rework debugging framework to use pr_debug and friends · bb33381d
      由 Daniel Borkmann 提交于 
      We should get rid of all own SCTP debug printk macros and use the ones
that the kernel offers anyway instead. This makes the code more readable
and conform to the kernel code, and offers all the features of dynamic
debbuging that pr_debug() et al has, such as only turning on/off portions
of debug messages at runtime through debugfs. The runtime cost of having
CONFIG_DYNAMIC_DEBUG enabled, but none of the debug statements printing,
is negligible [1]. If kernel debugging is completly turned off, then these
statements will also compile into "empty" functions.

While we're at it, we also need to change the Kconfig option as it /now/
only refers to the ifdef'ed code portions in outqueue.c that enable further
debugging/tracing of SCTP transaction fields. Also, since SCTP_ASSERT code
was enabled with this Kconfig option and has now been removed, we
transform those code parts into WARNs resp. where appropriate BUG_ONs so
that those bugs can be more easily detected as probably not many people
have SCTP debugging permanently turned on.

To turn on all SCTP debugging, the following steps are needed:

 # mount -t debugfs none /sys/kernel/debug
 # echo -n 'module sctp +p' > /sys/kernel/debug/dynamic_debug/control

This can be done more fine-grained on a per file, per line basis and others
as described in [2].

 [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-39-46.pdf
 [2] Documentation/dynamic-debug-howto.txt
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      bb33381d
  55. 18 6月, 2013 1 次提交
  57. 18 4月, 2013 1 次提交
  59. 05 2月, 2013 2 次提交
    • Y
      net: remove redundant check for timer pending state before del_timer · 25cc4ae9
      由 Ying Xue 提交于 
      As in del_timer() there has already placed a timer_pending() function
to check whether the timer to be deleted is pending or not, it's
unnecessary to check timer pending state again before del_timer() is
called.
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      25cc4ae9
    • D
      sctp: sctp_close: fix release of bindings for deferred call_rcu's · 8c98653f
      由 Daniel Borkmann 提交于 
      It seems due to RCU usage, i.e. within SCTP's address binding list,
a, say, ``behavioral change'' was introduced which does actually
not conform to the RFC anymore. In particular consider the following
(fictional) scenario to demonstrate this:

  do:
    Two SOCK_SEQPACKET-style sockets are opened (S1, S2)
    S1 is bound to 127.0.0.1, port 1024 [server]
    S2 is bound to 127.0.0.1, port 1025 [client]
    listen(2) is invoked on S1
    From S2 we call one sendmsg(2) with msg.msg_name and
       msg.msg_namelen parameters set to the server's
       address
    S1, S2 are closed
    goto do

The first pass of this loop passes successful, while the second round
fails during binding of S1 (address still in use). What is happening?
In the first round, the initial handshake is being done, and, at the
time close(2) is called on S1, a non-graceful shutdown is performed via
ABORT since in S1's receive queue an unprocessed packet is present,
thus stating an error condition. This can be considered as a correct
behavior.

During close also all bound addresses are freed, thus nothing *must*
be active anymore. In reference to RFC2960:

  After checking the Verification Tag, the receiving endpoint shall
  remove the association from its record, and shall report the
  termination to its upper layer. (9.1 Abort of an Association)

Also, no half-open states are supported, thus after an ungraceful
shutdown, we leave nothing behind. However, this seems not to be
happening though. In a real-world scenario, this is exactly where
it breaks the lksctp-tools functional test suite, *for instance*:

  ./test_sockopt
  test_sockopt.c  1 PASS : getsockopt(SCTP_STATUS) on a socket with no assoc
  test_sockopt.c  2 PASS : getsockopt(SCTP_STATUS)
  test_sockopt.c  3 PASS : getsockopt(SCTP_STATUS) with invalid associd
  test_sockopt.c  4 PASS : getsockopt(SCTP_STATUS) with NULL associd
  test_sockopt.c  5 BROK : bind: Address already in use

The underlying problem is that sctp_endpoint_destroy() hasn't been
triggered yet while the next bind attempt is being done. It will be
triggered eventually (but too late) by sctp_transport_destroy_rcu()
after one RCU grace period:

  sctp_transport_destroy()
    sctp_transport_destroy_rcu() ----.
      sctp_association_put() [*]  <--+--> sctp_packet_free()
        sctp_association_destroy()          [...]
          sctp_endpoint_put()                 skb->destructor
            sctp_endpoint_destroy()             sctp_wfree()
              sctp_bind_addr_free()               sctp_association_put() [*]

Thus, we move out the condition with sctp_association_put() as well as
the sctp_packet_free() invocation and the issue can be solved. We also
better free the SCTP chunks first before putting the ref of the association.

With this patch, the example above (which simulates a similar scenario
as in the implementation of this test case) and therefore also the test
suite run successfully through. Tested by myself.

Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      8c98653f
  61. 08 12月, 2012 1 次提交
  63. 04 12月, 2012 1 次提交
    • M
      sctp: Add support to per-association statistics via a new SCTP_GET_ASSOC_STATS call · 196d6759
      由 Michele Baldessari 提交于 
      The current SCTP stack is lacking a mechanism to have per association
statistics. This is an implementation modeled after OpenSolaris'
SCTP_GET_ASSOC_STATS.

Userspace part will follow on lksctp if/when there is a general ACK on
this.
V4:
- Move ipackets++ before q->immediate.func() for consistency reasons
- Move sctp_max_rto() at the end of sctp_transport_update_rto() to avoid
  returning bogus RTO values
- return asoc->rto_min when max_obs_rto value has not changed

V3:
- Increase ictrlchunks in sctp_assoc_bh_rcv() as well
- Move ipackets++ to sctp_inq_push()
- return 0 when no rto updates took place since the last call

V2:
- Implement partial retrieval of stat struct to cope for future expansion
- Kill the rtxpackets counter as it cannot be precise anyway
- Rename outseqtsns to outofseqtsns to make it clearer that these are out
  of sequence unexpected TSNs
- Move asoc->ipackets++ under a lock to avoid potential miscounts
- Fold asoc->opackets++ into the already existing asoc check
- Kill unneeded (q->asoc) test when increasing rtxchunks
- Do not count octrlchunks if sending failed (SCTP_XMIT_OK != 0)
- Don't count SHUTDOWNs as SACKs
- Move SCTP_GET_ASSOC_STATS to the private space API
- Adjust the len check in sctp_getsockopt_assoc_stats() to allow for
  future struct growth
- Move association statistics in their own struct
- Update idupchunks when we send a SACK with dup TSNs
- return min_rto in max_rto when RTO has not changed. Also return the
  transport when max_rto last changed.

Signed-off: Michele Baldessari <michele@acksyn.org>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      196d6759
  65. 29 11月, 2012 1 次提交
  67. 15 8月, 2012 1 次提交