Skip to content

L
linux
Switch branch/tag
  1. 09 Feb, 2015 22 commits
  3. 08 Feb, 2015 18 commits
    • Jon Paul Maloy's avatar
      tipc: fix bug in socket reception function · 51a00daf
      Jon Paul Maloy authored 
      In commit c637c103 ("tipc: resolve race
problem at unicast message reception") we introduced a time limit
for how long the function tipc_sk_eneque() would be allowed to execute
its loop. Unfortunately, the test for when this limit is passed was put
in the wrong place, resulting in a lost message when the test is true.

We fix this by moving the test to before we dequeue the next buffer
from the input queue.
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      51a00daf
    • Michael Büsch's avatar
      rt6_probe_deferred: Do not depend on struct ordering · 662f5533
      Michael Büsch authored 
      rt6_probe allocates a struct __rt6_probe_work and schedules a work handler rt6_probe_deferred.
But rt6_probe_deferred kfree's the struct work_struct instead of struct __rt6_probe_work.
This works, because struct work_struct is the first element of struct __rt6_probe_work.

Change it to kfree struct __rt6_probe_work to not implicitly depend on
struct work_struct being the first element.

This does not affect the generated code.
Signed-off-by: default avatarMichael Buesch <m@bues.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      662f5533
    • David S. Miller's avatar
      Merge branch 'tcp_ack_loops' · f06535c5
      David S. Miller authored 
      Neal Cardwellsays:

====================
tcp: mitigate TCP ACK loops due to out-of-window validation dupacks

This patch series mitigates "ack loop" DoS scenarios by rate-limiting
outgoing duplicate ACKs sent in response to incoming "out of window"
segments.

Background
-----------

There are several cases in which the TCP RFCs specify that a TCP
endpoint should send a pure duplicate ACK in response to a pure
duplicate ACK that appears to be invalid due to being "out of window":

(1) RFC 793 (section 3.9, page 69) specifies that endpoints should
    send a duplicate ACK in response to an ACK when the incoming
    sequence number is invalid due to being outside the receive
    window: "If an incoming segment is not acceptable, an
    acknowledgment should be sent in reply".

(2) RFC 793 (section 3.9, page 72) says: "If the ACK acknowledges
    something not yet sent (SEG.ACK > SND.NXT) then send an ACK".

(3) RFC 1323 (section 4.2.1, page 18) specifies that endpoints should
    send a duplicate ACK in response to an ACK when the PAWS check for
    the incoming timestamp value fails: "If .... SEG.TSval < TS.Recent
    and if TS.Recent is valid ... Send an acknowledgement in reply"

The problem
------------

Normally, this is not a problem. However, a buggy middlebox or
malicious man-in-the-middle can inject a few packets into the
conversation that advance each endpoint's notion of the current window
(sequence, ACK, or timestamp), without either side noticing. In this
case, from then on each side can think the other is sending invalid
segments. Thus an infinite feedback loop of duplicate ACKs can ensue,
as each endpoint receives a duplicate ACK, decides that it is invalid
(due to sequence number, ACK number, or timestamp), and then sends a
dupack in reply, which the other side decides is invalid, responding
with a dupack... ad infinitum. This ping-pong feedback loop can happen
at a very high rate.

This phenomenon can and does happen in practice. It has been seen in
datacenter and Internet contexts at Google, and has been documented by
Anil Agarwal in the Nov 2013 tcpm thread "TCP mismatched sequence
numbers issue", and Avery Fay in the Feb 2015 Linux netdev thread
"Invalid timestamp? causing tight ack loop (hundreds of thousands of
packets / sec)".

This patch series
------------------

This patch series mitigates such ack loops by rate-limiting outgoing
duplicate ACKs sent in response to incoming TCP packets that are for
an existing connection but that are invalid due to any of the reasons
mentioned above: sequence number (1), ACK field (2), or timestamp
value (3). The rate limit for such duplicate ACKs is specified by a
new sysctl, tcp_invalid_ratelimit, which specifies the minimal space
between such outbound duplicate ACKs, in milliseconds. The default is
500 (500ms), and 0 disables the mechanism.

We rate-limit these duplicate ACK responses rather than blocking them
entirely or resetting the connection, because legitimate connections
can rely on dupacks in response to some out-of-window segments. For
example, zero window probes are typically sent with a sequence number
that is below the current window, and ZWPs thus expect to thus elicit
a dupack in response.

Testing: this approach has been in use at Google for a while.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f06535c5
    • Neal Cardwell's avatar
      tcp: mitigate ACK loops for connections as tcp_timewait_sock · 4fb17a60
      Neal Cardwell authored 
      Ensure that in state FIN_WAIT2 or TIME_WAIT, where the connection is
represented by a tcp_timewait_sock, we rate limit dupacks in response
to incoming packets (a) with TCP timestamps that fail PAWS checks, or
(b) with sequence numbers that are out of the acceptable window.

We do not send a dupack in response to out-of-window packets if it has
been less than sysctl_tcp_invalid_ratelimit (default 500ms) since we
last sent a dupack in response to an out-of-window packet.
Reported-by: default avatarAvery Fay <avery@mixpanel.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4fb17a60
    • Neal Cardwell's avatar
      tcp: mitigate ACK loops for connections as tcp_sock · f2b2c582
      Neal Cardwell authored 
      Ensure that in state ESTABLISHED, where the connection is represented
by a tcp_sock, we rate limit dupacks in response to incoming packets
(a) with TCP timestamps that fail PAWS checks, or (b) with sequence
numbers or ACK numbers that are out of the acceptable window.

We do not send a dupack in response to out-of-window packets if it has
been less than sysctl_tcp_invalid_ratelimit (default 500ms) since we
last sent a dupack in response to an out-of-window packet.

There is already a similar (although global) rate-limiting mechanism
for "challenge ACKs". When deciding whether to send a challence ACK,
we first consult the new per-connection rate limit, and then the
global rate limit.
Reported-by: default avatarAvery Fay <avery@mixpanel.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f2b2c582
    • Neal Cardwell's avatar
      tcp: mitigate ACK loops for connections as tcp_request_sock · a9b2c06d
      Neal Cardwell authored 
      In the SYN_RECV state, where the TCP connection is represented by
tcp_request_sock, we now rate-limit SYNACKs in response to a client's
retransmitted SYNs: we do not send a SYNACK in response to client SYN
if it has been less than sysctl_tcp_invalid_ratelimit (default 500ms)
since we last sent a SYNACK in response to a client's retransmitted
SYN.

This allows the vast majority of legitimate client connections to
proceed unimpeded, even for the most aggressive platforms, iOS and
MacOS, which actually retransmit SYNs 1-second intervals for several
times in a row. They use SYN RTO timeouts following the progression:
1,1,1,1,1,2,4,8,16,32.
Reported-by: default avatarAvery Fay <avery@mixpanel.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a9b2c06d
    • Neal Cardwell's avatar
      tcp: helpers to mitigate ACK loops by rate-limiting out-of-window dupacks · 032ee423
      Neal Cardwell authored 
      Helpers for mitigating ACK loops by rate-limiting dupacks sent in
response to incoming out-of-window packets.

This patch includes:

- rate-limiting logic
- sysctl to control how often we allow dupacks to out-of-window packets
- SNMP counter for cases where we rate-limited our dupack sending

The rate-limiting logic in this patch decides to not send dupacks in
response to out-of-window segments if (a) they are SYNs or pure ACKs
and (b) the remote endpoint is sending them faster than the configured
rate limit.

We rate-limit our responses rather than blocking them entirely or
resetting the connection, because legitimate connections can rely on
dupacks in response to some out-of-window segments. For example, zero
window probes are typically sent with a sequence number that is below
the current window, and ZWPs thus expect to thus elicit a dupack in
response.

We allow dupacks in response to TCP segments with data, because these
may be spurious retransmissions for which the remote endpoint wants to
receive DSACKs. This is safe because segments with data can't
realistically be part of ACK loops, which by their nature consist of
each side sending pure/data-less ACKs to each other.

The dupack interval is controlled by a new sysctl knob,
tcp_invalid_ratelimit, given in milliseconds, in case an administrator
needs to dial this upward in the face of a high-rate DoS attack. The
name and units are chosen to be analogous to the existing analogous
knob for ICMP, icmp_ratelimit.

The default value for tcp_invalid_ratelimit is 500ms, which allows at
most one such dupack per 500ms. This is chosen to be 2x faster than
the 1-second minimum RTO interval allowed by RFC 6298 (section 2, rule
2.4). We allow the extra 2x factor because network delay variations
can cause packets sent at 1 second intervals to be compressed and
arrive much closer.
Reported-by: default avatarAvery Fay <avery@mixpanel.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      032ee423
    • Pravin B Shelar's avatar
      openvswitch: Initialize unmasked key and uid len · ca539345
      Pravin B Shelar authored 
      Flow alloc needs to initialize unmasked key pointer. Otherwise
it can crash kernel trying to free random unmasked-key pointer.

general protection fault: 0000 [#1] SMP
3.19.0-rc6-net-next+ #457
Hardware name: Supermicro X7DWU/X7DWU, BIOS  1.1 04/30/2008
RIP: 0010:[<ffffffff8111df0e>] [<ffffffff8111df0e>] kfree+0xac/0x196
Call Trace:
 [<ffffffffa060bd87>] flow_free+0x21/0x59 [openvswitch]
 [<ffffffffa060bde0>] ovs_flow_free+0x21/0x23 [openvswitch]
 [<ffffffffa0605b4a>] ovs_packet_cmd_execute+0x2f3/0x35f [openvswitch]
 [<ffffffffa0605995>] ? ovs_packet_cmd_execute+0x13e/0x35f [openvswitch]
 [<ffffffff811fe6fb>] ? nla_parse+0x4f/0xec
 [<ffffffff8139a2fc>] genl_family_rcv_msg+0x26d/0x2c9
 [<ffffffff8107620f>] ? __lock_acquire+0x90e/0x9aa
 [<ffffffff8139a3be>] genl_rcv_msg+0x66/0x89
 [<ffffffff8139a358>] ? genl_family_rcv_msg+0x2c9/0x2c9
 [<ffffffff81399591>] netlink_rcv_skb+0x3e/0x95
 [<ffffffff81399898>] ? genl_rcv+0x18/0x37
 [<ffffffff813998a7>] genl_rcv+0x27/0x37
 [<ffffffff81399033>] netlink_unicast+0x103/0x191
 [<ffffffff81399382>] netlink_sendmsg+0x2c1/0x310
 [<ffffffff811007ad>] ? might_fault+0x50/0xa0
 [<ffffffff8135c773>] do_sock_sendmsg+0x5f/0x7a
 [<ffffffff8135c799>] sock_sendmsg+0xb/0xd
 [<ffffffff8135cacf>] ___sys_sendmsg+0x1a3/0x218
 [<ffffffff8113e54b>] ? get_close_on_exec+0x86/0x86
 [<ffffffff8115a9d0>] ? fsnotify+0x32c/0x348
 [<ffffffff8115a720>] ? fsnotify+0x7c/0x348
 [<ffffffff8113e5f5>] ? __fget+0xaa/0xbf
 [<ffffffff8113e54b>] ? get_close_on_exec+0x86/0x86
 [<ffffffff8135cccd>] __sys_sendmsg+0x3d/0x5e
 [<ffffffff8135cd02>] SyS_sendmsg+0x14/0x16
 [<ffffffff81411852>] system_call_fastpath+0x12/0x17

Fixes: 74ed7ab9("openvswitch: Add support for unique flow IDs.")
CC: Joe Stringer <joestringer@nicira.com>
Reported-by: default avatarOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: default avatarPravin B Shelar <pshelar@nicira.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ca539345
    • David S. Miller's avatar
      Merge branch 'cxgb4' · 34afb4eb
      David S. Miller authored 
      Hariprasad Shenai says:

====================
Add support to dump some hw debug info

This patch series adds support to dump sensor info, dump Transport Processor
event trace, dump Upper Layer Protocol RX module command trace, dump mailbox
contents and dump Transport Processor congestion control configuration.

Will send a separate patch series for all the hw stats patches, by moving them
to ethtool.

The patches series is created against 'net-next' tree.
And includes patches on cxgb4 driver.

We have included all the maintainers of respective drivers. Kindly review the
change and let us know in case of any review comments.

V2: Dopped all hw stats related patches. Added a new patch which adds support to
dump congestion control table.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      34afb4eb
    • Hariprasad Shenai's avatar
      cxgb4: Add support in debugfs to dump the congestion control table · bad43792
      Hariprasad Shenai authored 
      Dump Transport Processor modules congestion control configuration
Signed-off-by: default avatarHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bad43792
    • Hariprasad Shenai's avatar
      cxgb4: Add support to dump mailbox content in debugfs · bf7c781d
      Hariprasad Shenai authored 
      Adds support to dump the current contents of mailbox and the driver which owns
it.
Signed-off-by: default avatarHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bf7c781d
    • Hariprasad Shenai's avatar
      cxgb4: Add support for ULP RX logic analyzer output in debugfs · 797ff0f5
      Hariprasad Shenai authored 
      Dump Upper Layer Protocol RX module command trace
Signed-off-by: default avatarHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      797ff0f5
    • Hariprasad Shenai's avatar
      cxgb4: Added support in debugfs to display TP logic analyzer output · 2d277b3b
      Hariprasad Shenai authored 
      Dump Transport Processor event trace.
Signed-off-by: default avatarHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2d277b3b
    • Hariprasad Shenai's avatar
      cxgb4: Add support in debugfs to display sensor information · 70a5f3bb
      Hariprasad Shenai authored 
      Dump out various chip sensor information. Currently Chip Temperature
and Core Voltage.
Signed-off-by: default avatarHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      70a5f3bb
    • David S. Miller's avatar
      Merge branch 'be2net' · bdb27482
      David S. Miller authored 
      Sathya Perla says:

====================
be2net: patch set

Hi Dave, pls consider applying the following patch-set to the
net-next tree. It has 5 code/style cleanup patches and 4 patches that
add functionality to the driver.

Patch 1 moves routines that were not needed to be in be.h to the respective
src files, to avoid unnecessary compilation.

Patch 2 replaces (1 << x) with BIT(x) macro

Patch 3 refactors code that checks if a FW flash file is compatible
with the adapter. The code is now refactored into 2 routines, the first one
gets the file type from the image file and the 2nd routine checks if the
file type is compatible with the adapter.

Patch 4 adds compatibility checks for flashing a FW image on the new
Skyhawk P2 HW revision.

Patch 5 adds support for a new "offset based" flashing scheme, wherein
the driver informs the FW of the offset at which each component in the flash
file is to be flashed at. This helps flashing components that were
previously not recognized by the running FW.

Patch 6 simplifies the be_cmd_rx_filter() routine, by passing to it the
filter flags already used in the FW cmd, instead of the netdev flags that
were converted to the FW-cmd flags.

Patch 7 introduces helper routines in be_set_rx_mode() and be_vid_config()
to improve code readability.

Patch 8 adds processing of port-misconfig async event sent by the FW.

Patch 9 removes unnecessary swapping of a field in the TX desc.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bdb27482
    • Sathya Perla's avatar
      be2net: avoid unncessary swapping of fields in eth_tx_wrb · f986afcb
      Sathya Perla authored 
      The 32-bit fields of a tx-wrb are little endian. The driver is currently
using be_dws_le_to_cpu() routine to swap (cpu to le) all the fields of
a tx-wrb. So, the rsvd field is also unnecessarily swapped.

This patch fixes this by individually swapping the required fields.
Also, the type of the fields in eth_tx_wrb{} is now changed to __le32
from u32 to avoid sparse warnings.
Signed-off-by: default avatarSathya Perla <sathya.perla@emulex.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f986afcb
    • Vasundhara Volam's avatar
      be2net: process port misconfig async event · 21252377
      Vasundhara Volam authored 
      This patch adds support for processing the port misconfigure async
event generated by the FW. This event is generated typically when an
optical module is incorrectly installed or is faulty.

This patch also moves the port_name field to the adapter struct for
logging the event. As the be_cmd_query_port_name() call is now moved
to be_get_config(), it is modified to use the mailbox instead of MCCQ
Signed-off-by: default avatarSathya Perla <sathya.perla@emulex.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      21252377
    • Sathya Perla's avatar
      be2net: refactor be_set_rx_mode() and be_vid_config() for readability · f66b7cfd
      Sathya Perla authored 
      This patch re-factors the filter setting (uc-list, mc-list, promisc, vlan)
code in be_set_rx_mode() and be_vid_config() to make it more readable
and reduce code duplication.
This patch adds a separate field to track the state/mode of filtering,
along with moving all the filtering related fields to one place in be
be_adapter structure.
Signed-off-by: default avatarSathya Perla <sathya.perla@emulex.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f66b7cfd
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7