Check with SCTP_FUTURE_ASSOC instead in
sctp_set/getsockopt_paddr_thresholds, it's compatible with 0.

It also adds pf_retrans in sctp_sock to support SCTP_FUTURE_ASSOC.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to add 3 constants SCTP_FUTURE_ASSOC,
SCTP_CURRENT_ASSOC and SCTP_ALL_ASSOC for reserved
assoc_ids, as defined in rfc6458#section-7.2.

And add the process for them when doing lookup and
inserting in sctp_id2assoc and sctp_assoc_set_id.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In sctp_hash_transport/sctp_epaddr_lookup_transport, it dereferences
a transport's asoc under rcu_read_lock while asoc is freed not after
a grace period, which leads to a use-after-free panic.

This patch fixes it by calling kfree_rcu to make asoc be freed after
a grace period.

Note that only the asoc's memory is delayed to free in the patch, it
won't cause sk to linger longer.

Thanks Neil and Marcelo to make this clear.

Fixes: 7fda702f ("sctp: use new rhlist interface on sctp transport rhashtable")
Fixes: cd2b7087 ("sctp: check duplicate node before inserting a new transport")
Reported-by: syzbot+0b05d8aa7cb185107483@syzkaller.appspotmail.com
Reported-by: syzbot+aad231d51b1923158444@syzkaller.appspotmail.com
Suggested-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_assoc_update_frag_point() should be called whenever asoc->pathmtu
changes, but we missed one place in sctp_association_init(). It would
cause frag_point is zero when sending data.

As says in Jakub's reproducer, if sp->pathmtu is set by socketopt, the
new asoc->pathmtu inherits it in sctp_association_init(). Later when
transports are added and their pmtu >= asoc->pathmtu, it will never
call sctp_assoc_update_frag_point() to set frag_point.

This patch is to fix it by updating frag_point after asoc->pathmtu is
set as sp->pathmtu in sctp_association_init(). Note that it moved them
after sctp_stream_init(), as stream->si needs to be set first.

Frag_point's calculation is also related with datachunk's type, so it
needs to update frag_point when stream->si may be changed in
sctp_process_init().

v1->v2:
  - call sctp_assoc_update_frag_point() separately in sctp_process_init
    and sctp_association_init, per Marcelo's suggestion.

Fixes: 2f5e3c9d ("sctp: introduce sctp_assoc_update_frag_point")
Reported-by: NJakub Audykowicz <jakub.audykowicz@gmail.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The member subscribe should be per asoc, so that sockopt SCTP_EVENT
in the next patch can subscribe a event from one asoc only.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If a transport is removed by asconf but there still are some chunks with
this transport queuing on out_chunk_list, later an use-after-free issue
will be caused when accessing this transport from these chunks in
sctp_outq_flush().

This is an old bug, we fix it by clearing the transport of these chunks
in out_chunk_list when removing a transport in sctp_assoc_rm_peer().

Reported-by: syzbot+56a40ceee5fb35932f4d@syzkaller.appspotmail.com
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Other than asoc pmtu sync from all transports, sctp_assoc_sync_pmtu
is also processing transport pmtu_pending by icmp packets. But it's
meaningless to use sctp_dst_mtu(t->dst) as new pmtu for a transport.

The right pmtu value should come from the icmp packet, and it would
be saved into transport->mtu_info in this patch and used later when
the pmtu sync happens in sctp_sendmsg_to_asoc or sctp_packet_config.

Besides, without this patch, as pmtu can only be updated correctly
when receiving a icmp packet and no place is holding sock lock, it
will take long time if the sock is busy with sending packets.

Note that it doesn't process transport->mtu_info in .release_cb(),
as there is no enough information for pmtu update, like for which
asoc or transport. It is not worth traversing all asocs to check
pmtu_pending. So unlike tcp, sctp does this in tx path, for which
mtu_info needs to be atomic_t.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Struct sockaddr_in6 has the member sin6_flowinfo that includes the
ipv6 flowlabel, it should also support for setting flowlabel when
adding a transport whose ipaddr is from userspace.

Note that addrinfo in sctp_sendmsg is using struct in6_addr for
the secondary addrs, which doesn't contain sin6_flowinfo, and
it needs to copy sin6_flowinfo from the primary addr.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Like some other per transport params, flowlabel and dscp are added
in transport, asoc and sctp_sock. By default, transport sets its
value from asoc's, and asoc does it from sctp_sock. flowlabel
only works for ipv6 transport.

Other than that they need to be passed down in sctp_xmit, flow4/6
also needs to set them before looking up route in get_dst.

Note that it uses '& 0x100000' to check if flowlabel is set and
'& 0x1' (tos 1st bit is unused) to check if dscp is set by users,
so that they could be set to 0 by sockopt in next patch.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now sctp only delays the authentication for the normal cookie-echo
chunk by setting chunk->auth_chunk in sctp_endpoint_bh_rcv(). But
for the duplicated one with auth, in sctp_assoc_bh_rcv(), it does
authentication first based on the old asoc, which will definitely
fail due to the different auth info in the old asoc.

The duplicated cookie-echo chunk will create a new asoc with the
auth info from this chunk, and the authentication should also be
done with the new asoc's auth info for all of the collision 'A',
'B' and 'D'. Otherwise, the duplicated cookie-echo chunk with auth
will never pass the authentication and create the new connection.

This issue exists since very beginning, and this fix is to make
sctp_assoc_bh_rcv() follow the way sctp_endpoint_bh_rcv() does
for the normal cookie-echo chunk to delay the authentication.

While at it, remove the unused params from sctp_sf_authenticate()
and define sctp_auth_chunk_verify() used for all the places that
do the delayed authentication.

v1->v2:
  fix the typo in changelog as Marcelo noticed.
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Which makes sure that the MTU respects the minimum value of
SCTP_DEFAULT_MINSEGMENT and that it is correctly aligned.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

and avoid the open-coded versions of it.

Now sctp_datamsg_from_user can just re-use asoc->frag_point as it will
always be updated.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All changes to asoc PMTU should now go through this wrapper, making it
easier to track them and to do other actions upon it.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As noticed by Xin Long, the if() here is always true as PMTU can never
be 0.
Reported-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There was only one case that sctp_assoc_add_peer couldn't handle, which
is when SPP_PMTUD_DISABLE is set and pathmtu not initialized.
So add this situation to sctp_transport_route and reuse what was
already in there.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After Commit 4f008781 ("sctp: apply rhashtable api to send/recv
path"), there's no place using sctp_assoc_is_match, so remove it.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 3dbcc105 ("sctp: alloc stream info when initializing
asoc"), stream and stream.out info are always alloced when creating
an asoc.

So it's not correct to check !asoc->stream before updating stream
info when processing dupcookie, but would be better to check asoc
state instead.

Fixes: 3dbcc105 ("sctp: alloc stream info when initializing asoc")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is almost to revert commit 02f3d4ce ("sctp: Adjust PMTU
updates to accomodate route invalidation."). As t->asoc can't be NULL
in sctp_transport_update_pmtu, it could get sk from asoc, and no need
to pass sk into that function.

It is also to remove some duplicated codes from that function.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the unnecessary temporary variable 'err' from
sctp_association_init.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NYueHaibing <yuehaibing@huawei.com>
Fixes: 5110effe ("net: Do delayed neigh confirmation.")
Fixes: f2bb4bed ("ipv4: Cache output routes in fib_info nexthops.")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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>

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: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Reviewed-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>