/proc has been ignoring struct file_operations::owner field for 10 years.
Specifically, it started with commit 786d7e16
("Fix rmmod/read/write races in /proc entries"). Notice the chunk where
inode->i_fop is initialized with proxy struct file_operations for
regular files:

	-               if (de->proc_fops)
	-                       inode->i_fop = de->proc_fops;
	+               if (de->proc_fops) {
	+                       if (S_ISREG(inode->i_mode))
	+                               inode->i_fop = &proc_reg_file_ops;
	+                       else
	+                               inode->i_fop = de->proc_fops;
	+               }

VFS stopped pinning module at this point.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The check in sctp_sockaddr_af is not robust enough to forbid binding a
v4mapped v6 addr on a v4 socket.

The worse thing is that v4 socket's bind_verify would not convert this
v4mapped v6 addr to a v4 addr. syzbot even reported a crash as the v4
socket bound a v6 addr.

This patch is to fix it by doing the common sa.sa_family check first,
then AF_INET check for v4mapped v6 addrs.

Fixes: 7dab83de ("sctp: Support ipv6only AF_INET6 sockets.")
Reported-by: syzbot+7b7b518b1228d2743963@syzkaller.appspotmail.com
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
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>

After commit cea0cc80 ("sctp: use the right sk after waking up from
wait_buf sleep"), it may change to lock another sk if the asoc has been
peeled off in sctp_wait_for_sndbuf.

However, the asoc's new sk could be already closed elsewhere, as it's in
the sendmsg context of the old sk that can't avoid the new sk's closing.
If the sk's last one refcnt is held by this asoc, later on after putting
this asoc, the new sk will be freed, while under it's own lock.

This patch is to revert that commit, but fix the old issue by returning
error under the old sk's lock.

Fixes: cea0cc80 ("sctp: use the right sk after waking up from wait_buf sleep")
Reported-by: syzbot+ac6ea7baa4432811eb50@syzkaller.appspotmail.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>

After introducing sctp_stream structure, sctp uses stream->outcnt as the
out stream nums instead of c.sinit_num_ostreams.

However when users use sinit in cmsg, it only updates c.sinit_num_ostreams
in sctp_sendmsg. At that moment, stream->outcnt is still using previous
value. If it's value is not updated, the sinit_num_ostreams of sinit could
not really work.

This patch is to fix it by updating stream->outcnt and reiniting stream
if stream outcnt has been change by sinit in sendmsg.

Fixes: a8386317 ("sctp: prepare asoc stream for stream reconf")
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>

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

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

Some sockopt handling functions were calculating the length of the
buffer to be written to userspace and then calculating it again when
actually writing the buffer, which could lead to some write not using
an up-to-date length.

This patch updates such places to just make use of the len variable.

Also, replace some sizeof(type) to sizeof(var).
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Hangbin Liu reported that some sockopt calls could cause the kernel to log
a warning on memory allocation failure if the user supplied a large optlen
value. That is because some of them called memdup_user() without a ceiling
on optlen, allowing it to try to allocate really large buffers.

This patch adds a ceiling by limiting optlen to the maximum allowed that
would still make sense for these sockopt.
Reported-by: NHangbin Liu <haliu@redhat.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

So replace it with GFP_USER and also add __GFP_NOWARN.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot reported a hang involving SCTP, on which it kept flooding dmesg
with the message:
[  246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512

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

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

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

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

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

See-also: https://lkml.org/lkml/2017/12/22/811Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, if PMTU discovery is disabled on a given transport, but the
configured value is higher than the actual PMTU, it is likely that we
will get some icmp Frag Needed. The issue is, if PMTU discovery is
disabled, we won't update the information and will issue a
retransmission immediately, which may very well trigger another ICMP,
and another retransmission, leading to a loop.

The fix is to simply not trigger immediate retransmissions if PMTU
discovery is disabled on the given transport.

Changes from v2:
- updated stale comment, noticed by Xin Long
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot noticed a NULL pointer dereference panic in sctp_stream_free()
which was caused by an incomplete error handling in sctp_stream_init().
By not clearing stream->outcnt, it made a for() in sctp_stream_free()
think that it had elements to free, but not, leading to the panic.

As suggested by Xin Long, this patch also simplifies the error path by
moving it to the only if() that uses it.

See-also: https://www.spinics.net/lists/netdev/msg473756.html
See-also: https://www.spinics.net/lists/netdev/msg465024.htmlReported-by: Nsyzbot <syzkaller@googlegroups.com>
Fixes: f952be79 ("sctp: introduce struct sctp_stream_out_ext")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove SCTP probe module since jprobe has been deprecated.
That function is now replaced by sctp/sctp_probe and
sctp/sctp_probe_path trace-events.
You can use it via ftrace or perftools.
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add SCTP ACK tracking trace event to trace the changes of SCTP
association state in response to incoming packets.
It is used for debugging SCTP congestion control algorithms,
and will replace sctp_probe module.

Note that this event a bit tricky. Since this consists of 2
events (sctp_probe and sctp_probe_path) so you have to enable
both events as below.

  # cd /sys/kernel/debug/tracing
  # echo 1 > events/sctp/sctp_probe/enable
  # echo 1 > events/sctp/sctp_probe_path/enable

Or, you can enable all the events under sctp.

  # echo 1 > events/sctp/enable

Since sctp_probe_path event is always invoked from sctp_probe
event, you can not see any output if you only enable
sctp_probe_path.
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The patch(180d8cd9) replaces all uses of struct sock fields'
memory_pressure, memory_allocated, sockets_allocated, and sysctl_mem
to accessor macros. But the sockets_allocated field of sctp sock is
not replaced at all. Then replace it now for unifying the code.

Fixes: 180d8cd9 ("foundations of per-cgroup memory pressure controlling.")
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: NTonghao Zhang <zhangtonghao@didichuxing.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With changes in inet_ files, SCTP state transitions are traced with
inet_sock_set_state tracepoint.
As SCTP state names, i.e. SCTP_SS_CLOSED, SCTP_SS_ESTABLISHED,
have the same value with TCP state names. So the output info still print
the TCP state names, that makes the code easy.
Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Whenever a new type of chunk is added, the corresp conversion in
sctp_cname should be added. Otherwise, in some places, pr_debug
will print it as "unknown chunk".

Fixes: cc16f00f ("sctp: add support for generating stream reconf ssn reset request chunk")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now when reneging events in sctp_ulpq_renege(), the variable freed
could be increased by a __u16 value twice while freed is of __u16
type. It means freed may overflow at the second addition.

This patch is to fix it by using __u32 type for 'freed', while at
it, also to remove 'if (chunk)' check, as all renege commands are
generated in sctp_eat_data and it can't be NULL.
Reported-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>

This is the last patch for support of stream interleave, after this patch,
users could enable stream interleave by systcl -w net.sctp.intl_enable=1.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When using idata and doing stream and asoc reset, setting ssn with
0 could only clear the 1st 16 bits of mid.

So to make this work for both data and idata, it sets mid with 0
instead of ssn, and also mid_uo for unordered idata also need to
be cleared, as said in section 2.3.2 of RFC8260.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As Marcelo said in the stream scheduler patch:

  Support for I-DATA chunks, also described in RFC8260, with user message
  interleaving is straightforward as it just requires the schedulers to
  probe for the feature and ignore datamsg boundaries when dequeueing.

All needs to do is just to ignore datamsg boundaries when dequeueing.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

handle_ftsn is added as a member of sctp_stream_interleave, used to skip
ssn for data or mid for idata, called for SCTP_CMD_PROCESS_FWDTSN cmd.

sctp_handle_iftsn works for ifwdtsn, and sctp_handle_fwdtsn works for
fwdtsn. Note that different from sctp_handle_fwdtsn, sctp_handle_iftsn
could do stream abort pd.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

report_ftsn is added as a member of sctp_stream_interleave, used to
skip tsn from tsnmap, remove old events from reasm or lobby queue,
and abort pd for data or idata, called for SCTP_CMD_REPORT_FWDTSN
cmd and asoc reset.

sctp_report_iftsn works for ifwdtsn, and sctp_report_fwdtsn works
for fwdtsn. Note that sctp_report_iftsn doesn't do asoc abort_pd,
as stream abort_pd will be done when handling ifwdtsn. But when
ftsn is equal with ftsn, which means asoc reset, asoc abort_pd has
to be done.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

validate_ftsn is added as a member of sctp_stream_interleave, used to
validate ssn/chunk type for fwdtsn or mid (message id)/chunk type for
ifwdtsn, called in sctp_sf_eat_fwd_tsn, just as validate_data.

If this check fails, an abort packet will be sent, as said in section
2.3.1 of RFC8260.

As ifwdtsn and fwdtsn chunks have different length, it also defines
ftsn_chunk_len for sctp_stream_interleave to describe the chunk size.
Then it replaces all sizeof(struct sctp_fwdtsn_chunk) with
sctp_ftsnchk_len.

It also adds the process for ifwdtsn in rx path. As Marcelo pointed
out, there's no need to add event table for ifwdtsn, but just share
prsctp_chunk_event_table with fwdtsn's. It would drop fwdtsn chunk
for ifwdtsn and drop ifwdtsn chunk for fwdtsn by calling validate_ftsn
in sctp_sf_eat_fwd_tsn.

After this patch, the ifwdtsn can be accepted.

Note that this patch also removes the sctp.intl_enable check for
idata chunks in sctp_chunk_event_lookup, as it will do this check
in validate_data later.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

generate_ftsn is added as a member of sctp_stream_interleave, used to
create fwdtsn or ifwdtsn chunk according to abandoned chunks, called
in sctp_retransmit and sctp_outq_sack.

sctp_generate_iftsn works for ifwdtsn, and sctp_generate_fwdtsn is
still used for making fwdtsn.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_ifwdtsn_skip, sctp_ifwdtsn_hdr and sctp_ifwdtsn_chunk are used to
define and parse I-FWD TSN chunk format, and sctp_make_ifwdtsn is a
function to build the chunk.

The I-FORWARD-TSN Chunk Format is defined in section 2.3.1 of RFC8260.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now in sctp_setsockopt_reset_streams, it only does the check
optlen < sizeof(*params) for optlen. But it's not enough, as
params->srs_number_streams should also match optlen.

If the streams in params->srs_stream_list are less than stream
nums in params->srs_number_streams, later when dereferencing
the stream list, it could cause a slab-out-of-bounds crash, as
reported by syzbot.

This patch is to fix it by also checking the stream numbers in
sctp_setsockopt_reset_streams to make sure at least it's not
greater than the streams in the list.

Fixes: 7f9d68ac ("sctp: implement sender-side procedures for SSN Reset Request Parameter")
Reported-by: NDmitry Vyukov <dvyukov@google.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>

Unordered idata process is more complicated than unordered data:

 - It has to add mid into sctp_stream_out to save the next mid value,
   which is separated from ordered idata's.

 - To support pd for unordered idata, another mid and pd_mode need to
   be added to save the message id and pd state in sctp_stream_in.

 - To make  unordered idata reasm easier, it adds a new event queue
   to save frags for idata.

The patch mostly adds the samilar reasm functions for unordered idata
as ordered idata's, and also adjusts some other codes on assign_mid,
abort_pd and ulpevent_data for idata.
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>

abort_pd is added as a member of sctp_stream_interleave, used to abort
partial delivery for data or idata, called in sctp_cmd_assoc_failed.

Since stream interleave allows to do partial delivery for each stream
at the same time, sctp_intl_abort_pd for idata would be very different
from the old function sctp_ulpq_abort_pd for data.

Note that sctp_ulpevent_make_pdapi will support per stream in this
patch by adding pdapi_stream and pdapi_seq in sctp_pdapi_event, as
described in section 6.1.7 of RFC6458.
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>

start_pd is added as a member of sctp_stream_interleave, used to
do partial_delivery for data or idata when datalen >= asoc->rwnd
in sctp_eat_data. The codes have been done in last patches, but
they need to be extracted into start_pd, so that it could be used
for SCTP_CMD_PART_DELIVER cmd as well.
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>

renege_events is added as a member of sctp_stream_interleave, used to
renege some old data or idata in reasm or lobby queue properly to free
some memory for the new data when there's memory stress.

It defines sctp_renege_events for idata, and leaves sctp_ulpq_renege
as it is for data.
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>

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>

ulpevent_data is added as a member of sctp_stream_interleave, used to
do the most process in ulpq, including to convert data or idata chunk
to event, reasm them in reasm queue and put them in lobby queue in
right order, and deliver them up to user sk rx queue.

This procedure is described in section 2.2.3 of RFC8260.

It adds most functions for idata here to do the similar process as
the old functions for data. But since the details are very different
between them, the old functions can not be reused for idata.

event->ssn and event->ppid settings are moved to ulpevent_data from
sctp_ulpevent_make_rcvmsg, so that sctp_ulpevent_make_rcvmsg could
work for both data and idata.

Note that mid is added in sctp_ulpevent for idata, __packed has to
be used for defining sctp_ulpevent, or it would exceeds the skb cb
that saves a sctp_ulpevent variable for ulp layer process.
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>

validate_data is added as a member of sctp_stream_interleave, used
to validate ssn/chunk type for data or mid (message id)/chunk type
for idata, called in sctp_eat_data.

If this check fails, an abort packet will be sent, as said in
section 2.2.3 of RFC8260.

It also adds the process for idata in rx path. As Marcelo pointed
out, there's no need to add event table for idata, but just share
chunk_event_table with data's. It would drop data chunk for idata
and drop idata chunk for data by calling validate_data in
sctp_eat_data.

As last patch did, it also replaces sizeof(struct sctp_data_chunk)
with sctp_datachk_len for rx path.

After this patch, the idata can be accepted and delivered to ulp
layer.
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>

assign_number is added as a member of sctp_stream_interleave, used
to assign ssn for data or mid (message id) for idata, called in
sctp_packet_append_data. sctp_chunk_assign_ssn is left as it is,
and sctp_chunk_assign_mid is added for sctp_stream_interleave_1.

This procedure is described in section 2.2.2 of RFC8260.

All sizeof(struct sctp_data_chunk) in tx path is replaced with
sctp_datachk_len, to make it right for idata as well. And also
adjust sctp_chunk_is_data for SCTP_CID_I_DATA.

After this patch, idata can be built and sent in tx path.

Note that if sp strm_interleave is set, it has to wait_connect in
sctp_sendmsg, as asoc intl_enable need to be known after 4 shake-
hands, to decide if it should use data or idata later. data and
idata can't be mixed to send in one asoc.
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>

To avoid hundreds of checks for the different process on I-DATA chunk,
struct sctp_stream_interleave is defined as a group of functions used
to replace the codes in some place where it needs to do different job
according to if the asoc intl_enabled is set.

With these ops, it only needs to initialize asoc->stream.si with
sctp_stream_interleave_0 for normal data if asoc intl_enable is 0,
or sctp_stream_interleave_1 for idata if asoc intl_enable is set in
sctp_stream_init.

After that, the members in asoc->stream.si can be used directly in
some special places without checking asoc intl_enable.

make_datafrag is the first member for sctp_stream_interleave, it's
used to make data or idata frags, called in sctp_datamsg_from_user.
The old function sctp_make_datafrag_empty needs to be adjust some
to fit in this ops.

Note that as idata and data chunks have different length, it also
defines data_chunk_len for sctp_stream_interleave to describe the
chunk size.
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_idatahdr and sctp_idata_chunk are used to define and parse
I-DATA chunk format, and sctp_make_idata is a function to build
the chunk.

The I-DATA Chunk Format is defined in section 2.1 of RFC8260.
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>

asoc intl_enable will be set when local sp strm_interleave is set
and there's I-DATA chunk in init and init_ack extensions, as said
in section 2.2.1 of RFC8260.

asoc intl_enable indicates all data will be sent as I-DATA chunks.
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>

This patch adds intl_enable in asoc and netns, and strm_interleave in
sctp_sock to indicate if stream interleave is enabled and supported.

netns intl_enable would be set via procfs, but that is not added yet
until all stream interleave codes are completely implemented; asoc
intl_enable will be set when doing 4-shakehands.

sp strm_interleave can be set by sockopt SCTP_INTERLEAVING_SUPPORTED
which is also added in this patch. This socket option is defined in
section 4.3.1 of RFC8260.

Note that strm_interleave can only be set by sockopt when both netns
intl_enable and sp frag_interleave are set.
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>

Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.
Signed-off-by: NTom Herbert <tom@quantonium.net>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>