mirror of https://gitee.com/openkylin/linux.git
180 Commits
| Author | SHA1 | Message | Date |
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Xin Long
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9162e0ed9e |
sctp: implement enqueue_event for sctp_stream_interleave
enqueue_event is added as a member of sctp_stream_interleave, used to enqueue either data, idata or notification events into user socket rx queue. It replaces sctp_ulpq_tail_event used in the other places with enqueue_event. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Kees Cook
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9c3b575183 |
net: sctp: Convert timers to use timer_setup()
In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-sctp@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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bfc6f8270f |
sctp: remove the typedef sctp_subtype_t
This patch is to remove the typedef sctp_subtype_t, and replace with union sctp_subtype in the places where it's using this typedef. Note that it doesn't fix many indents although it should, as sctp_disposition_t's removal would mess them up again. So better to fix them when removing sctp_disposition_t in later patch. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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0ceaeebe28 |
sctp: remove the typedef sctp_transport_cmd_t
This patch is to remove the typedef sctp_transport_cmd_t, and replace with enum sctp_transport_cmd in the places where it's using this typedef. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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1c662018d2 |
sctp: remove the typedef sctp_scope_t
This patch is to remove the typedef sctp_scope_t, and replace with enum sctp_scope in the places where it's using this typedef. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Reshetova, Elena
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c638457a7c |
net, sctp: convert sctp_ep_common.refcnt from atomic_t to refcount_t
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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3c91870492 |
sctp: remove the typedef sctp_paramhdr_t
This patch is to remove the typedef sctp_paramhdr_t, and replace with struct sctp_paramhdr in the places where it's using this typedef. It is also to fix some indents and use sizeof(variable) instead of sizeof(type). Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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5ee8aa6897 |
sctp: handle errors when updating asoc
It's a bad thing not to handle errors when updating asoc. The memory allocation failure in any of the functions called in sctp_assoc_update() would cause sctp to work unexpectedly. This patch is to fix it by aborting the asoc and reporting the error when any of these functions fails. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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4abf5a653b |
sctp: no need to check assoc id before calling sctp_assoc_set_id
sctp_assoc_set_id does the assoc id check in the beginning when processing dupcookie, no need to do the same check before calling it. v1->v2: fix some typo errs Marcelo pointed in changelog. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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ff356414dc |
sctp: merge sctp_stream_new and sctp_stream_init
Since last patch, sctp doesn't need to alloc memory for asoc->stream any more. sctp_stream_new and sctp_stream_init both are used to alloc memory for stream.in or stream.out, and their names are also confusing. This patch is to merge them into sctp_stream_init, and only pass stream and streamcnt parameters into it, instead of the whole asoc. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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cee360ab4d |
sctp: define the member stream as an object instead of pointer in asoc
As Marcelo's suggestion, stream is a fixed size member of asoc and would not grow with more streams. To avoid an allocation for it, this patch is to define it as an object instead of pointer and update the places using it, also create sctp_stream_update() called in sctp_assoc_update() to migrate the stream info from one stream to another. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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3ab2137915 |
sctp: fix stream update when processing dupcookie
Since commit |
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Xin Long
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3ebfdf0821 |
sctp: get sock from transport in sctp_transport_update_pmtu
This patch is almost to revert commit
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Xin Long
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3dbcc105d5 |
sctp: alloc stream info when initializing asoc
When sending a msg without asoc established, sctp will send INIT packet first and then enqueue chunks. Before receiving INIT_ACK, stream info is not yet alloced. But enqueuing chunks needs to access stream info, like out stream state and out stream cnt. This patch is to fix it by allocing out stream info when initializing an asoc, allocing in stream and re-allocing out stream when processing init. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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581947787e |
sctp: remove useless err from sctp_association_init
This patch is to remove the unnecessary temporary variable 'err' from sctp_association_init. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Julian Anastasov
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c86a773c78 |
sctp: add dst_pending_confirm flag
Add new transport flag to allow sockets to confirm neighbour. When same struct dst_entry can be used for many different neighbours we can not use it for pending confirmations. The flag is propagated from transport to every packet. It is reset when cached dst is reset. Reported-by: YueHaibing <yuehaibing@huawei.com> Fixes: |
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Xin Long
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9fb657aec0 |
sctp: add sockopt SCTP_ENABLE_STREAM_RESET
This patch is to add sockopt SCTP_ENABLE_STREAM_RESET to get/set strreset_enable to indicate which reconf request type it supports, which is described in rfc6525 section 6.3.1. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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c28445c3cb |
sctp: add reconf_enable in asoc ep and netns
This patch is to add reconf_enable field in all of asoc ep and netns to indicate if they support stream reset. When initializing, asoc reconf_enable get the default value from ep reconf_enable which is from netns netns reconf_enable by default. It is also to add reconf_capable in asoc peer part to know if peer supports reconf_enable, the value is set if ext params have reconf chunk support when processing init chunk, just as rfc6525 section 5.1.1 demands. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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7b9438de0c |
sctp: add stream reconf timer
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: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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cc16f00f65 |
sctp: add support for generating stream reconf ssn reset request chunk
This patch is to add asoc strreset_outseq and strreset_inseq for saving the reconf request sequence, initialize them when create assoc and process init, and also to define Incoming and Outgoing SSN Reset Request Parameter described in rfc6525 section 4.1 and 4.2, As they can be in one same chunk as section rfc6525 3.1-3 describes, it makes them in one function. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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a83863174a |
sctp: prepare asoc stream for stream reconf
sctp stream reconf, described in RFC 6525, needs a structure to
save per stream information in assoc, like stream state.
In the future, sctp stream scheduler also needs it to save some
stream scheduler params and queues.
This patchset is to prepare the stream array in assoc for stream
reconf. It defines sctp_stream that includes stream arrays inside
to replace ssnmap.
Note that we use different structures for IN and OUT streams, as
the members in per OUT stream will get more and more different
from per IN stream.
v1->v2:
- put these patches into a smaller group.
v2->v3:
- define sctp_stream to contain stream arrays, and create stream.c
to put stream-related functions.
- merge 3 patches into 1, as new sctp_stream has the same name
with before.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Marcelo Ricardo Leitner
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1636098c46 |
sctp: fix recovering from 0 win with small data chunks
Currently if SCTP closes the receive window with window pressure, mostly caused by excessive skb overhead on payload/overheads ratio, SCTP will close the window abruptly while saving the delta on rwnd_press. It will start recovering rwnd as the chunks are consumed by the application and the rwnd_press will be only recovered after rwnd reach the same value as of rwnd_press, mostly to prevent silly window syndrome. Thing is, this is very inefficient with small data chunks, as with those it will never reach back that value, and thus it will never recover from such pressure. This means that we will not issue window updates when recovering from 0 window and will rely on a sender retransmit to notice it. The fix here is to remove such threshold, as no value is good enough: it depends on the (avg) chunk sizes being used. Test with netperf -t SCTP_STREAM -- -m 1, and trigger 0 window by sending SIGSTOP to netserver, sleep 1.2, and SIGCONT. Rate limited to 845kbps, for visibility. Capture done at netserver side. Previously: 01.500751 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632372996] [a_rwnd 99153] [ 01.500752 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632372997] [SID: 0] [SS 01.517471 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373010] [SID: 0] [SS 01.517483 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632373009] [a_rwnd 0] [#gap 01.517485 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373083] [SID: 0] [SS 01.517488 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632373009] [a_rwnd 0] [#gap 01.534168 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373096] [SID: 0] [SS 01.534180 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632373009] [a_rwnd 0] [#gap 01.534181 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373169] [SID: 0] [SS 01.534185 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632373009] [a_rwnd 0] [#gap 02.525978 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373010] [SID: 0] [SS 02.526021 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632373009] [a_rwnd 0] [#gap (window update missed) 04.573807 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373010] [SID: 0] [SS 04.779370 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632373082] [a_rwnd 859] [#g 04.789162 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373083] [SID: 0] [SS 04.789323 IP A.36925 > B.48277: sctp (1) [DATA] (B)(E) [TSN: 632373156] [SID: 0] [SS 04.789372 IP B.48277 > A.36925: sctp (1) [SACK] [cum ack 632373228] [a_rwnd 786] [#g After: 02.568957 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098728] [a_rwnd 99153] 02.568961 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098729] [SID: 0] [S 02.585631 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098742] [SID: 0] [S 02.585666 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 0] [#ga 02.585671 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098815] [SID: 0] [S 02.585683 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 0] [#ga 02.602330 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098828] [SID: 0] [S 02.602359 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 0] [#ga 02.602363 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098901] [SID: 0] [S 02.602372 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 0] [#ga 03.600788 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098742] [SID: 0] [S 03.600830 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 0] [#ga 03.619455 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 13508] 03.619479 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 27017] 03.619497 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 40526] 03.619516 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 54035] 03.619533 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 67544] 03.619552 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 81053] 03.619570 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098741] [a_rwnd 94562] (following data transmission triggered by window updates above) 03.633504 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098742] [SID: 0] [S 03.836445 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098814] [a_rwnd 100000] 03.843125 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098815] [SID: 0] [S 03.843285 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098888] [SID: 0] [S 03.843345 IP B.50536 > A.55173: sctp (1) [SACK] [cum ack 2490098960] [a_rwnd 99894] 03.856546 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490098961] [SID: 0] [S 03.866450 IP A.55173 > B.50536: sctp (1) [DATA] (B)(E) [TSN: 2490099011] [SID: 0] [S Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Marcelo Ricardo Leitner
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58b94d88de |
sctp: do not loose window information if in rwnd_over
It's possible that we receive a packet that is larger than current window. If it's the first packet in this way, it will cause it to increase rwnd_over. Then, if we receive another data chunk (specially as SCTP allows you to have one data chunk in flight even during 0 window), rwnd_over will be overwritten instead of added to. In the long run, this could cause the window to grow bigger than its initial size, as rwnd_over would be charged only for the last received data chunk while the code will try open the window for all packets that were received and had its value in rwnd_over overwritten. This, then, can lead to the worsening of payload/buffer ratio and cause rwnd_press to kick in more often. The fix is to sum it too, same as is done for rwnd_press, so that if we receive 3 chunks after closing the window, we still have to release that same amount before re-opening it. Log snippet from sctp_test exhibiting the issue: [ 146.209232] sctp: sctp_assoc_rwnd_decrease: asoc:ffff88013928e000 rwnd decreased by 1 to (0, 1, 114221) [ 146.209232] sctp: sctp_assoc_rwnd_decrease: association:ffff88013928e000 has asoc->rwnd:0, asoc->rwnd_over:1! [ 146.209232] sctp: sctp_assoc_rwnd_decrease: asoc:ffff88013928e000 rwnd decreased by 1 to (0, 1, 114221) [ 146.209232] sctp: sctp_assoc_rwnd_decrease: association:ffff88013928e000 has asoc->rwnd:0, asoc->rwnd_over:1! [ 146.209232] sctp: sctp_assoc_rwnd_decrease: asoc:ffff88013928e000 rwnd decreased by 1 to (0, 1, 114221) [ 146.209232] sctp: sctp_assoc_rwnd_decrease: association:ffff88013928e000 has asoc->rwnd:0, asoc->rwnd_over:1! [ 146.209232] sctp: sctp_assoc_rwnd_decrease: asoc:ffff88013928e000 rwnd decreased by 1 to (0, 1, 114221) Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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7fda702f93 |
sctp: use new rhlist interface on sctp transport rhashtable
Now sctp transport rhashtable uses hash(lport, dport, daddr) as the key to hash a node to one chain. If in one host thousands of assocs connect to one server with the same lport and different laddrs (although it's not a normal case), all the transports would be hashed into the same chain. It may cause to keep returning -EBUSY when inserting a new node, as the chain is too long and sctp inserts a transport node in a loop, which could even lead to system hangs there. The new rhlist interface works for this case that there are many nodes with the same key in one chain. It puts them into a list then makes this list be as a node of the chain. This patch is to replace rhashtable_ interface with rhltable_ interface. Since a chain would not be too long and it would not return -EBUSY with this fix when inserting a node, the reinsert loop is also removed here. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Marcelo Ricardo Leitner
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e2f036a972 |
sctp: rename WORD_TRUNC/ROUND macros
To something more meaningful these days, specially because this is working on packet headers or lengths and which are not tied to any CPU arch but to the protocol itself. So, WORD_TRUNC becomes SCTP_TRUNC4 and WORD_ROUND becomes SCTP_PAD4. Reported-by: David Laight <David.Laight@ACULAB.COM> Reported-by: David Miller <davem@davemloft.net> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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28aa4c26fc |
sctp: add SCTP_PR_SUPPORTED on sctp sockopt
According to section 4.5 of rfc7496, prsctp_enable should be per asoc. We will add prsctp_enable to both asoc and ep, and replace the places where it used net.sctp->prsctp_enable with asoc->prsctp_enable. ep->prsctp_enable will be initialized with net.sctp->prsctp_enable, and asoc->prsctp_enable will be initialized with ep->prsctp_enable. We can also modify it's value through sockopt SCTP_PR_SUPPORTED. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Marcelo Ricardo Leitner
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3822a5ff4b |
sctp: align MTU to a word
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: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Marcelo Ricardo Leitner
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cea8768f33 |
sctp: allow sctp_transmit_packet and others to use gfp
Currently sctp_sendmsg() triggers some calls that will allocate memory with GFP_ATOMIC even when not necessary. In the case of sctp_packet_transmit it will allocate a linear skb that will be used to construct the packet and this may cause sends to fail due to ENOMEM more often than anticipated specially with big MTUs. This patch thus allows it to inherit gfp flags from upper calls so that it can use GFP_KERNEL if it was triggered by a sctp_sendmsg call or similar. All others, like retransmits or flushes started from BH, are still allocated using GFP_ATOMIC. In netperf tests this didn't result in any performance drawbacks when memory is not too fragmented and made it trigger ENOMEM way less often. Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Xin Long
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39d2adebf1 |
sctp: fix the transports round robin issue when init is retransmitted
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:
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Xin Long
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4f00878126 |
sctp: apply rhashtable api to send/recv path
apply lookup apis to two functions, for __sctp_endpoint_lookup_assoc and __sctp_lookup_association, it's invoked in the protection of sock lock, it will be safe, but sctp_lookup_association need to call rcu_read_lock() and to detect the t->dead to protect it. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Mel Gorman
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d0164adc89 |
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Denys Vlasenko
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2103d6b818 |
net: sctp: Don't use 64 kilobyte lookup table for four elements
Seemingly innocuous sctp_trans_state_to_prio_map[] array is way bigger than it looks, since "[SCTP_UNKNOWN] = 2" expands into "[0xffff] = 2" ! This patch replaces it with switch() statement. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> CC: Vlad Yasevich <vyasevich@gmail.com> CC: Neil Horman <nhorman@tuxdriver.com> CC: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> CC: linux-sctp@vger.kernel.org CC: netdev@vger.kernel.org CC: linux-kernel@vger.kernel.org Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Markus Elfring
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7d37d0c159 |
net: sctp: Deletion of an unnecessary check before the function call "kfree"
The kfree() function tests whether its argument is NULL and then returns immediately. Thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Acked-By: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Daniel Borkmann
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600ddd6825 |
net: sctp: fix slab corruption from use after free on INIT collisions
When hitting an INIT collision case during the 4WHS with AUTH enabled, as already described in detail in commit |
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Daniel Borkmann
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b69040d8e3 |
net: sctp: fix panic on duplicate ASCONF chunks
When receiving a e.g. semi-good formed connection scan in the form of ... -------------- INIT[ASCONF; ASCONF_ACK] -------------> <----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------ -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- ---------------- ASCONF_a; ASCONF_b -----------------> ... where ASCONF_a equals ASCONF_b chunk (at least both serials need to be equal), we panic an SCTP server! The problem is that good-formed ASCONF chunks that we reply with ASCONF_ACK chunks are cached per serial. Thus, when we receive a same ASCONF chunk twice (e.g. through a lost ASCONF_ACK), we do not need to process them again on the server side (that was the idea, also proposed in the RFC). Instead, we know it was cached and we just resend the cached chunk instead. So far, so good. Where things get nasty is in SCTP's side effect interpreter, that is, sctp_cmd_interpreter(): While incoming ASCONF_a (chunk = event_arg) is being marked !end_of_packet and !singleton, and we have an association context, we do not flush the outqueue the first time after processing the ASCONF_ACK singleton chunk via SCTP_CMD_REPLY. Instead, we keep it queued up, although we set local_cork to 1. Commit |
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Daniel Borkmann
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aa4a83ee8b |
net: sctp: fix suboptimal edge-case on non-active active/retrans path selection
In SCTP, selection of active (T.ACT) and retransmission (T.RET) transports is being done whenever transport control operations (UP, DOWN, PF, ...) are engaged through sctp_assoc_control_transport(). Commits |
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Daniel Borkmann
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ea4f19c1f8 |
net: sctp: spare unnecessary comparison in sctp_trans_elect_best
When both transports are the same, we don't have to go down that road only to realize that we will return the very same transport. We are guaranteed that curr is always non-NULL. Therefore, just short-circuit this special case. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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zhuyj
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061079ac0b |
sctp: not send SCTP_PEER_ADDR_CHANGE notifications with failed probe
Since the transport has always been in state SCTP_UNCONFIRMED, it therefore wasn't active before and hasn't been used before, and it always has been, so it is unnecessary to bug the user with a notification. Reported-by: Deepak Khandelwal <khandelwal.deepak.1987@gmail.com> Suggested-by: Vlad Yasevich <vyasevich@gmail.com> Suggested-by: Michael Tuexen <tuexen@fh-muenster.de> Suggested-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Zhu Yanjun <Yanjun.Zhu@windriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Daniel Borkmann
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1be9a950c6 |
net: sctp: inherit auth_capable on INIT collisions
Jason reported an oops caused by SCTP on his ARM machine with SCTP authentication enabled: Internal error: Oops: 17 [#1] ARM CPU: 0 PID: 104 Comm: sctp-test Not tainted 3.13.0-68744-g3632f30c9b20-dirty #1 task: c6eefa40 ti: c6f52000 task.ti: c6f52000 PC is at sctp_auth_calculate_hmac+0xc4/0x10c LR is at sg_init_table+0x20/0x38 pc : [<c024bb80>] lr : [<c00f32dc>] psr: 40000013 sp : c6f538e8 ip : 00000000 fp : c6f53924 r10: c6f50d80 r9 : 00000000 r8 : 00010000 r7 : 00000000 r6 : c7be4000 r5 : 00000000 r4 : c6f56254 r3 : c00c8170 r2 : 00000001 r1 : 00000008 r0 : c6f1e660 Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 0005397f Table: 06f28000 DAC: 00000015 Process sctp-test (pid: 104, stack limit = 0xc6f521c0) Stack: (0xc6f538e8 to 0xc6f54000) [...] Backtrace: [<c024babc>] (sctp_auth_calculate_hmac+0x0/0x10c) from [<c0249af8>] (sctp_packet_transmit+0x33c/0x5c8) [<c02497bc>] (sctp_packet_transmit+0x0/0x5c8) from [<c023e96c>] (sctp_outq_flush+0x7fc/0x844) [<c023e170>] (sctp_outq_flush+0x0/0x844) from [<c023ef78>] (sctp_outq_uncork+0x24/0x28) [<c023ef54>] (sctp_outq_uncork+0x0/0x28) from [<c0234364>] (sctp_side_effects+0x1134/0x1220) [<c0233230>] (sctp_side_effects+0x0/0x1220) from [<c02330b0>] (sctp_do_sm+0xac/0xd4) [<c0233004>] (sctp_do_sm+0x0/0xd4) from [<c023675c>] (sctp_assoc_bh_rcv+0x118/0x160) [<c0236644>] (sctp_assoc_bh_rcv+0x0/0x160) from [<c023d5bc>] (sctp_inq_push+0x6c/0x74) [<c023d550>] (sctp_inq_push+0x0/0x74) from [<c024a6b0>] (sctp_rcv+0x7d8/0x888) While we already had various kind of bugs in that area |
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Xufeng Zhang
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d3217b15a1 |
sctp: Fix sk_ack_backlog wrap-around problem
Consider the scenario: For a TCP-style socket, while processing the COOKIE_ECHO chunk in sctp_sf_do_5_1D_ce(), after it has passed a series of sanity check, a new association would be created in sctp_unpack_cookie(), but afterwards, some processing maybe failed, and sctp_association_free() will be called to free the previously allocated association, in sctp_association_free(), sk_ack_backlog value is decremented for this socket, since the initial value for sk_ack_backlog is 0, after the decrement, it will be 65535, a wrap-around problem happens, and if we want to establish new associations afterward in the same socket, ABORT would be triggered since sctp deem the accept queue as full. Fix this issue by only decrementing sk_ack_backlog for associations in the endpoint's list. Fix-suggested-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Daniel Borkmann
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9b87d46510 |
net: sctp: fix incorrect type in gfp initializer
This fixes the following sparse warning: net/sctp/associola.c:1556:29: warning: incorrect type in initializer (different base types) net/sctp/associola.c:1556:29: expected bool [unsigned] [usertype] preload net/sctp/associola.c:1556:29: got restricted gfp_t Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Daniel Borkmann
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a7288c4dd5 |
net: sctp: improve sctp_select_active_and_retran_path selection
In function sctp_select_active_and_retran_path(), we walk the
transport list in order to look for the two most recently used
ACTIVE transports (trans_pri, trans_sec). In case we didn't find
anything ACTIVE, we currently just camp on a possibly PF or
INACTIVE transport that is primary path; this behavior actually
dates back to linux-history tree of the very early days of
lksctp, and can yield a behavior that chooses suboptimal
transport paths.
Instead, be a bit more clever by reusing and extending the
recently introduced sctp_trans_elect_best() handler. In case
both transports are evaluated to have the same score resulting
from their states, break the tie by looking at: 1) transport
patch error count 2) last_time_heard value from each transport.
This is analogous to Nishida's Quick Failover draft [1],
section 5.1, 3:
The sender SHOULD avoid data transmission to PF destinations.
When all destinations are in either PF or Inactive state,
the sender MAY either move the destination from PF to active
state (and transmit data to the active destination) or the
sender MAY transmit data to a PF destination. In the former
scenario, (i) the sender MUST NOT notify the ULP about the
state transition, and (ii) MUST NOT clear the destination's
error counter. It is recommended that the sender picks the
PF destination with least error count (fewest consecutive
timeouts) for data transmission. In case of a tie (multiple PF
destinations with same error count), the sender MAY choose the
last active destination.
Thus for sctp_select_active_and_retran_path(), we keep track of
the best, if any, transport that is in PF state and in case no
ACTIVE transport has been found (hence trans_{pri,sec} is NULL),
we select the best out of the three: current primary_path and
retran_path as well as a possible PF transport.
The secondary may still camp on the original primary_path as
before. The change in sctp_trans_elect_best() with a more fine
grained tie selection also improves at the same time path selection
for sctp_assoc_update_retran_path() in case of non-ACTIVE states.
[1] http://tools.ietf.org/html/draft-nishida-tsvwg-sctp-failover-05
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Daniel Borkmann
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e575235fc6 |
net: sctp: migrate most recently used transport to ktime
Be more precise in transport path selection and use ktime helpers instead of jiffies to compare and pick the better primary and secondary recently used transports. This also avoids any side-effects during a possible roll-over, and could lead to better path decision-making. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Daniel Borkmann
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b82e8f31ac |
net: sctp: refactor active path selection
This patch just refactors and moves the code for the active path selection into its own helper function outside of sctp_assoc_control_transport() which is already big enough. No functional changes here. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Daniel Borkmann
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362d52040c |
Revert "net: sctp: Fix a_rwnd/rwnd management to reflect real state of the receiver's buffer"
This reverts commit |
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Daniel Borkmann
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433131ba03 |
net: sctp: remove NULL check in sctp_assoc_update_retran_path
This is basically just to let Coverity et al shut up. Remove an
unneeded NULL check in sctp_assoc_update_retran_path().
It is safe to remove it, because in sctp_assoc_update_retran_path()
we iterate over the list of transports, our own transport which is
asoc->peer.retran_path included. In the iteration, we skip the
list head element and transports in state SCTP_UNCONFIRMED.
Such transports came from peer addresses received in INIT/INIT-ACK
address parameters. They are not yet confirmed by a heartbeat and
not available for data transfers.
We know however that in the list of transports, even if it contains
such elements, it at least contains our asoc->peer.retran_path as
well, so even if next to that element, we only encounter
SCTP_UNCONFIRMED transports, we are always going to fall back to
asoc->peer.retran_path through sctp_trans_elect_best(), as that is
for sure not SCTP_UNCONFIRMED as per
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Daniel Borkmann
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4c47af4d5e |
net: sctp: rework multihoming retransmission path selection to rfc4960
Problem statement: 1) both paths (primary path1 and alternate path2) are up after the association has been established i.e., HB packets are normally exchanged, 2) path2 gets inactive after path_max_retrans * max_rto timed out (i.e. path2 is down completely), 3) now, if a transmission times out on the only surviving/active path1 (any ~1sec network service impact could cause this like a channel bonding failover), then the retransmitted packets are sent over the inactive path2; this happens with partial failover and without it. Besides not being optimal in the above scenario, a small failure or timeout in the only existing path has the potential to cause long delays in the retransmission (depending on RTO_MAX) until the still active path is reselected. Further, when the T3-timeout occurs, we have active_patch == retrans_path, and even though the timeout occurred on the initial transmission of data, not a retransmit, we end up updating retransmit path. RFC4960, section 6.4. "Multi-Homed SCTP Endpoints" states under 6.4.1. "Failover from an Inactive Destination Address" the following: Some of the transport addresses of a multi-homed SCTP endpoint may become inactive due to either the occurrence of certain error conditions (see Section 8.2) or adjustments from the SCTP user. When there is outbound data to send and the primary path becomes inactive (e.g., due to failures), or where the SCTP user explicitly requests to send data to an inactive destination transport address, before reporting an error to its ULP, the SCTP endpoint should try to send the data to an alternate __active__ destination transport address if one exists. When retransmitting data that timed out, if the endpoint is multihomed, it should consider each source-destination address pair in its retransmission selection policy. When retransmitting timed-out data, the endpoint should attempt to pick the most divergent source-destination pair from the original source-destination pair to which the packet was transmitted. Note: Rules for picking the most divergent source-destination pair are an implementation decision and are not specified within this document. So, we should first reconsider to take the current active retransmission transport if we cannot find an alternative active one. If all of that fails, we can still round robin through unkown, partial failover, and inactive ones in the hope to find something still suitable. Commit |
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Matija Glavinic Pecotic
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ef2820a735 |
net: sctp: Fix a_rwnd/rwnd management to reflect real state of the receiver's buffer
Implementation of (a)rwnd calculation might lead to severe performance issues
and associations completely stalling. These problems are described and solution
is proposed which improves lksctp's robustness in congestion state.
1) Sudden drop of a_rwnd and incomplete window recovery afterwards
Data accounted in sctp_assoc_rwnd_decrease takes only payload size (sctp data),
but size of sk_buff, which is blamed against receiver buffer, is not accounted
in rwnd. Theoretically, this should not be the problem as actual size of buffer
is double the amount requested on the socket (SO_RECVBUF). Problem here is
that this will have bad scaling for data which is less then sizeof sk_buff.
E.g. in 4G (LTE) networks, link interfacing radio side will have a large portion
of traffic of this size (less then 100B).
An example of sudden drop and incomplete window recovery is given below. Node B
exhibits problematic behavior. Node A initiates association and B is configured
to advertise rwnd of 10000. A sends messages of size 43B (size of typical sctp
message in 4G (LTE) network). On B data is left in buffer by not reading socket
in userspace.
Lets examine when we will hit pressure state and declare rwnd to be 0 for
scenario with above stated parameters (rwnd == 10000, chunk size == 43, each
chunk is sent in separate sctp packet)
Logic is implemented in sctp_assoc_rwnd_decrease:
socket_buffer (see below) is maximum size which can be held in socket buffer
(sk_rcvbuf). current_alloced is amount of data currently allocated (rx_count)
A simple expression is given for which it will be examined after how many
packets for above stated parameters we enter pressure state:
We start by condition which has to be met in order to enter pressure state:
socket_buffer < currently_alloced;
currently_alloced is represented as size of sctp packets received so far and not
yet delivered to userspace. x is the number of chunks/packets (since there is no
bundling, and each chunk is delivered in separate packet, we can observe each
chunk also as sctp packet, and what is important here, having its own sk_buff):
socket_buffer < x*each_sctp_packet;
each_sctp_packet is sctp chunk size + sizeof(struct sk_buff). socket_buffer is
twice the amount of initially requested size of socket buffer, which is in case
of sctp, twice the a_rwnd requested:
2*rwnd < x*(payload+sizeof(struc sk_buff));
sizeof(struct sk_buff) is 190 (3.13.0-rc4+). Above is stated that rwnd is 10000
and each payload size is 43
20000 < x(43+190);
x > 20000/233;
x ~> 84;
After ~84 messages, pressure state is entered and 0 rwnd is advertised while
received 84*43B ~= 3612B sctp data. This is why external observer notices sudden
drop from 6474 to 0, as it will be now shown in example:
IP A.34340 > B.12345: sctp (1) [INIT] [init tag: 1875509148] [rwnd: 81920] [OS: 10] [MIS: 65535] [init TSN: 1096057017]
IP B.12345 > A.34340: sctp (1) [INIT ACK] [init tag: 3198966556] [rwnd: 10000] [OS: 10] [MIS: 10] [init TSN: 902132839]
IP A.34340 > B.12345: sctp (1) [COOKIE ECHO]
IP B.12345 > A.34340: sctp (1) [COOKIE ACK]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057017] [SID: 0] [SSEQ 0] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057017] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057018] [SID: 0] [SSEQ 1] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057018] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057019] [SID: 0] [SSEQ 2] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057019] [a_rwnd 9914] [#gap acks 0] [#dup tsns 0]
<...>
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057098] [SID: 0] [SSEQ 81] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057098] [a_rwnd 6517] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057099] [SID: 0] [SSEQ 82] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057099] [a_rwnd 6474] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057100] [SID: 0] [SSEQ 83] [PPID 0x18]
--> Sudden drop
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
At this point, rwnd_press stores current rwnd value so it can be later restored
in sctp_assoc_rwnd_increase. This however doesn't happen as condition to start
slowly increasing rwnd until rwnd_press is returned to rwnd is never met. This
condition is not met since rwnd, after it hit 0, must first reach rwnd_press by
adding amount which is read from userspace. Let us observe values in above
example. Initial a_rwnd is 10000, pressure was hit when rwnd was ~6500 and the
amount of actual sctp data currently waiting to be delivered to userspace
is ~3500. When userspace starts to read, sctp_assoc_rwnd_increase will be blamed
only for sctp data, which is ~3500. Condition is never met, and when userspace
reads all data, rwnd stays on 3569.
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 1505] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 3010] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057101] [SID: 0] [SSEQ 84] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057101] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0]
--> At this point userspace read everything, rwnd recovered only to 3569
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057102] [SID: 0] [SSEQ 85] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057102] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0]
Reproduction is straight forward, it is enough for sender to send packets of
size less then sizeof(struct sk_buff) and receiver keeping them in its buffers.
2) Minute size window for associations sharing the same socket buffer
In case multiple associations share the same socket, and same socket buffer
(sctp.rcvbuf_policy == 0), different scenarios exist in which congestion on one
of the associations can permanently drop rwnd of other association(s).
Situation will be typically observed as one association suddenly having rwnd
dropped to size of last packet received and never recovering beyond that point.
Different scenarios will lead to it, but all have in common that one of the
associations (let it be association from 1)) nearly depleted socket buffer, and
the other association blames socket buffer just for the amount enough to start
the pressure. This association will enter pressure state, set rwnd_press and
announce 0 rwnd.
When data is read by userspace, similar situation as in 1) will occur, rwnd will
increase just for the size read by userspace but rwnd_press will be high enough
so that association doesn't have enough credit to reach rwnd_press and restore
to previous state. This case is special case of 1), being worse as there is, in
the worst case, only one packet in buffer for which size rwnd will be increased.
Consequence is association which has very low maximum rwnd ('minute size', in
our case down to 43B - size of packet which caused pressure) and as such
unusable.
Scenario happened in the field and labs frequently after congestion state (link
breaks, different probabilities of packet drop, packet reordering) and with
scenario 1) preceding. Here is given a deterministic scenario for reproduction:
>From node A establish two associations on the same socket, with rcvbuf_policy
being set to share one common buffer (sctp.rcvbuf_policy == 0). On association 1
repeat scenario from 1), that is, bring it down to 0 and restore up. Observe
scenario 1). Use small payload size (here we use 43). Once rwnd is 'recovered',
bring it down close to 0, as in just one more packet would close it. This has as
a consequence that association number 2 is able to receive (at least) one more
packet which will bring it in pressure state. E.g. if association 2 had rwnd of
10000, packet received was 43, and we enter at this point into pressure,
rwnd_press will have 9957. Once payload is delivered to userspace, rwnd will
increase for 43, but conditions to restore rwnd to original state, just as in
1), will never be satisfied.
--> Association 1, between A.y and B.12345
IP A.55915 > B.12345: sctp (1) [INIT] [init tag: 836880897] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 4032536569]
IP B.12345 > A.55915: sctp (1) [INIT ACK] [init tag: 2873310749] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3799315613]
IP A.55915 > B.12345: sctp (1) [COOKIE ECHO]
IP B.12345 > A.55915: sctp (1) [COOKIE ACK]
--> Association 2, between A.z and B.12346
IP A.55915 > B.12346: sctp (1) [INIT] [init tag: 534798321] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 2099285173]
IP B.12346 > A.55915: sctp (1) [INIT ACK] [init tag: 516668823] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3676403240]
IP A.55915 > B.12346: sctp (1) [COOKIE ECHO]
IP B.12346 > A.55915: sctp (1) [COOKIE ACK]
--> Deplete socket buffer by sending messages of size 43B over association 1
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315613] [SID: 0] [SSEQ 0] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315613] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
<...>
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315696] [a_rwnd 6388] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315697] [SID: 0] [SSEQ 84] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315697] [a_rwnd 6345] [#gap acks 0] [#dup tsns 0]
--> Sudden drop on 1
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315698] [SID: 0] [SSEQ 85] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315698] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Here userspace read, rwnd 'recovered' to 3698, now deplete again using
association 1 so there is place in buffer for only one more packet
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315799] [SID: 0] [SSEQ 186] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315799] [a_rwnd 86] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315800] [SID: 0] [SSEQ 187] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 43] [#gap acks 0] [#dup tsns 0]
--> Socket buffer is almost depleted, but there is space for one more packet,
send them over association 2, size 43B
IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403240] [SID: 0] [SSEQ 0] [PPID 0x18]
IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403240] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Immediate drop
IP A.60995 > B.12346: sctp (1) [SACK] [cum ack 387491510] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Read everything from the socket, both association recover up to maximum rwnd
they are capable of reaching, note that association 1 recovered up to 3698,
and association 2 recovered only to 43
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 1548] [#gap acks 0] [#dup tsns 0]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 3053] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315801] [SID: 0] [SSEQ 188] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315801] [a_rwnd 3698] [#gap acks 0] [#dup tsns 0]
IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403241] [SID: 0] [SSEQ 1] [PPID 0x18]
IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403241] [a_rwnd 43] [#gap acks 0] [#dup tsns 0]
A careful reader might wonder why it is necessary to reproduce 1) prior
reproduction of 2). It is simply easier to observe when to send packet over
association 2 which will push association into the pressure state.
Proposed solution:
Both problems share the same root cause, and that is improper scaling of socket
buffer with rwnd. Solution in which sizeof(sk_buff) is taken into concern while
calculating rwnd is not possible due to fact that there is no linear
relationship between amount of data blamed in increase/decrease with IP packet
in which payload arrived. Even in case such solution would be followed,
complexity of the code would increase. Due to nature of current rwnd handling,
slow increase (in sctp_assoc_rwnd_increase) of rwnd after pressure state is
entered is rationale, but it gives false representation to the sender of current
buffer space. Furthermore, it implements additional congestion control mechanism
which is defined on implementation, and not on standard basis.
Proposed solution simplifies whole algorithm having on mind definition from rfc:
o Receiver Window (rwnd): This gives the sender an indication of the space
available in the receiver's inbound buffer.
Core of the proposed solution is given with these lines:
sctp_assoc_rwnd_update:
if ((asoc->base.sk->sk_rcvbuf - rx_count) > 0)
asoc->rwnd = (asoc->base.sk->sk_rcvbuf - rx_count) >> 1;
else
asoc->rwnd = 0;
We advertise to sender (half of) actual space we have. Half is in the braces
depending whether you would like to observe size of socket buffer as SO_RECVBUF
or twice the amount, i.e. size is the one visible from userspace, that is,
from kernelspace.
In this way sender is given with good approximation of our buffer space,
regardless of the buffer policy - we always advertise what we have. Proposed
solution fixes described problems and removes necessity for rwnd restoration
algorithm. Finally, as proposed solution is simplification, some lines of code,
along with some bytes in struct sctp_association are saved.
Version 2 of the patch addressed comments from Vlad. Name of the function is set
to be more descriptive, and two parts of code are changed, in one removing the
superfluous call to sctp_assoc_rwnd_update since call would not result in update
of rwnd, and the other being reordering of the code in a way that call to
sctp_assoc_rwnd_update updates rwnd. Version 3 corrected change introduced in v2
in a way that existing function is not reordered/copied in line, but it is
correctly called. Thanks Vlad for suggesting.
Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nsn.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller
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143c905494 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts: drivers/net/ethernet/intel/i40e/i40e_main.c drivers/net/macvtap.c Both minor merge hassles, simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net> |
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Neil Horman
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9f70f46bd4 |
sctp: properly latch and use autoclose value from sock to association
Currently, sctp associations latch a sockets autoclose value to an association at association init time, subject to capping constraints from the max_autoclose sysctl value. This leads to an odd situation where an application may set a socket level autoclose timeout, but sliently sctp will limit the autoclose timeout to something less than that. Fix this by modifying the autoclose setsockopt function to check the limit, cap it and warn the user via syslog that the timeout is capped. This will allow getsockopt to return valid autoclose timeout values that reflect what subsequent associations actually use. While were at it, also elimintate the assoc->autoclose variable, it duplicates whats in the timeout array, which leads to multiple sources for the same information, that may differ (as the former isn't subject to any capping). This gives us the timeout information in a canonical place and saves some space in the association structure as well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> CC: Wang Weidong <wangweidong1@huawei.com> CC: David Miller <davem@davemloft.net> CC: Vlad Yasevich <vyasevich@gmail.com> CC: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net> |