This patch added a new member named csum in struct mptcp_ext, implemented
a new function named mptcp_generate_data_checksum().

Generate the data checksum in mptcp_sendmsg_frag, save it in mpext->csum.

Note that we must generate the csum for zero window probe, too.

Do the csum update incrementally, to avoid multiple csum computation
when the data is appended to existing skb.

Note that in a later patch we will skip unneeded csum related operation.
Changes not included here to keep the delta small.
Co-developed-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added a new member named csum_enabled in struct mptcp_sock,
used a dummy mptcp_is_checksum_enabled() helper to initialize it.

Also added a new member named mptcpi_csum_enabled in struct mptcp_info
to expose the csum_enabled flag.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This adds support for SO_TIMESTAMP(NS).  Timestamps are passed to
userspace in the same way as for plain tcp sockets.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

MPTCP sk_forward_memory handling is a bit special, as such field
is protected by the msk socket spin_lock, instead of the plain
socket lock.

Currently we have a code path updating such field without handling
the relevant lock:

__mptcp_retrans() -> __mptcp_clean_una_wakeup()

Several helpers in __mptcp_clean_una_wakeup() will update
sk_forward_alloc, possibly causing such field corruption, as reported
by Matthieu.

Address the issue providing and using a new variant of blamed function
which explicitly acquires the msk spin lock.

Fixes: 64b9cea7 ("mptcp: fix spurious retransmissions")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/172Reported-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Tested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

We can't use tcp_set_congestion_control() on an mptcp socket, as
such function can end-up accessing a tcp-specific field -
prior_ssthresh - causing an OOB access.

To allow propagating the correct ca algo on subflow, cache the ca
name at initialization time.

Additionally avoid overriding the user-selected CA (if any) at
clone time.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/182
Fixes: aa1fbd94 ("mptcp: sockopt: add TCP_CONGESTION and TCP_INFO")
Acked-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Maxim reported several issues when forcing a TCP transparent proxy
to use the MPTCP protocol for the inbound connections. He also
provided a clean reproducer.

The problem boils down to 'mptcp_frag_can_collapse_to()' assuming
that only MPTCP will use the given page_frag.

If others - e.g. the plain TCP protocol - allocate page fragments,
we can end-up re-using already allocated memory for mptcp_data_frag.

Fix the issue ensuring that the to-be-expanded data fragment is
located at the current page frag end.

v1 -> v2:
 - added missing fixes tag (Mat)

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/178Reported-and-tested-by: NMaxim Galaganov <max@internet.ru>
Fixes: 18b683bf ("mptcp: queue data for mptcp level retransmission")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds support for MSG_PEEK flag. Packets are not removed
from the receive_queue if MSG_PEEK set in recv() system call.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NYonglong Li <liyonglong@chinatelecom.cn>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently mptcp_sendmsg() fails with EOPNOTSUPP if the
user-space provides some unsupported flag. That is unexpected
and may foul existing applications migrated to MPTCP, which
expect a different behavior.

Change the mentioned function to silently ignore the unsupported
flags except MSG_FASTOPEN. This is the only flags currently not
supported by MPTCP with user-space visible side-effects.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/162Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The mentioned flag is currently silenlty ignored. This
change implements the TCP-like behaviour, dropping the
pending data up to the specified length.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Sigend-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

mptcp_recvmsg() currently silently ignores MSG_ERRQUEUE, returning
input data instead of error cmsg.

This change provides a dummy implementation for MSG_ERRQUEUE - always
returns no data. That is consistent with the current lack of a suitable
IP_RECVERR setsockopt() support.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With this change, the MPTCP-level retransmission timer is used to resend
DATA_FIN. The retranmit timer is not stopped while waiting for a
MPTCP-level ACK of DATA_FIN, and retransmitted DATA_FINs are sent on all
subflows. The retry interval starts at TCP_RTO_MIN and then doubles on
each attempt, up to TCP_RTO_MAX.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/146
Fixes: 43b54c6e ("mptcp: Use full MPTCP-level disconnect state machine")
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch used the macro helper mptcp_for_each_subflow() instead of
list_for_each_entry() in mptcp_close.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added a tracepoint in the packet scheduler function
mptcp_subflow_get_send().
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch moved the static function mptcp_subflow_active to protocol.h
as an inline one.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some of the sequence numbers are printed as the negative ones in the debug
log:

[   46.250932] MPTCP: DSS
[   46.250940] MPTCP: data_fin=0 dsn64=0 use_map=0 ack64=1 use_ack=1
[   46.250948] MPTCP: data_ack=2344892449471675613
[   46.251012] MPTCP: msk=000000006e157e3f status=10
[   46.251023] MPTCP: msk=000000006e157e3f snd_data_fin_enable=0 pending=0 snd_nxt=2344892449471700189 write_seq=2344892449471700189
[   46.251343] MPTCP: msk=00000000ec44a129 ssk=00000000f7abd481 sending dfrag at seq=-1658937016627538668 len=100 already sent=0
[   46.251360] MPTCP: data_seq=16787807057082012948 subflow_seq=1 data_len=100 dsn64=1

This patch used the format specifier %u instead of %d for the unsigned int
values to fix it.

Fixes: d9ca1de8 ("mptcp: move page frag allocation in mptcp_sendmsg()")
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP_CONGESTION is set for all subflows.
The mptcp socket gains icsk_ca_ops too so it can be used to keep the
authoritative state that should be set on new/future subflows.

TCP_INFO will return first subflow only.
The out-of-tree kernel has a MPTCP_INFO getsockopt, this could be added
later on.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Paolo Abeni suggested to avoid re-syncing new subflows because
they inherit options from listener. In case options were set on
listener but are not set on mptcp-socket there is no need to
do any synchronisation for new subflows.

This change sets sockopt_seq of new mptcp sockets to the seq of
the mptcp listener sock.

Subflow sequence is set to the embedded tcp listener sk.
Add a comment explaing why sk_state is involved in sockopt_seq
generation.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Handle following cases:
1. setsockopt is called with multiple subflows.
   Change might have to be mirrored to all of them.
   This is done directly in process context/setsockopt call.
2. Outgoing subflow is created after one or several setsockopt()
   calls have been made.  Old setsockopt changes should be
   synced to the new socket.
3. Incoming subflow, after setsockopt call(s).

Cases 2 and 3 are handled right after the join list is spliced to the conn
list.

Not all sockopt values can be just be copied by value, some require
helper calls.  Those can acquire socket lock (which can sleep).

If the join->conn list splicing is done from preemptible context,
synchronization can be done right away, otherwise its deferred to work
queue.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The MPTCP sockopt implementation is going to be much
more big and complex soon. Let's move it to a different
source file.

No functional change intended.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change reverts commit 86581852 ("mptcp: forbit mcast-related sockopt on MPTCP sockets").

As announced in the cover letter of the mentioned patch above, the
following commits introduce a larger MPTCP sockopt implementation
refactor.

This time, we switch from a blocklist to an allowlist. This is safer for
the future where new sockoptions could be added while not being fully
supported with MPTCP sockets and thus causing unstabilities.
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The MPTCP reset option allows to carry a mptcp-specific error code that
provides more information on the nature of a connection reset.

Reset option data received gets stored in the subflow context so it can
be sent to userspace via the 'subflow closed' netlink event.

When a subflow is closed, the desired error code that should be sent to
the peer is also placed in the subflow context structure.

If a reset is sent before subflow establishment could complete, e.g. on
HMAC failure during an MP_JOIN operation, the mptcp skb extension is
used to store the reset information.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently we explicitly check for the first subflow being
NULL in a couple of places, even if we don't need any
special actions in such scenario.

Just drop the unneeded checks, to avoid confusion.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We are not currently tracking the active MPTCP connection
attempts. Let's add the related counters.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the MPTCP protocol is unable to create a new token,
the socket fallback to plain TCP, let's keep track
of such events via a specific MIB.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change reverts commit ad98dd37 ("mptcp: provide subflow aware
release function"). The latter introduced a deadlock spotted by
syzkaller and is not needed anymore after the previous commit.

Fixes: ad98dd37 ("mptcp: provide subflow aware release function")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Unrolling mcast state at msk dismantel time is bug prone, as
syzkaller reported:

======================================================
WARNING: possible circular locking dependency detected
5.11.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor905/8822 is trying to acquire lock:
ffffffff8d678fe8 (rtnl_mutex){+.+.}-{3:3}, at: ipv6_sock_mc_close+0xd7/0x110 net/ipv6/mcast.c:323

but task is already holding lock:
ffff888024390120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1600 [inline]
ffff888024390120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: mptcp6_release+0x57/0x130 net/mptcp/protocol.c:3507

which lock already depends on the new lock.

Instead we can simply forbit any mcast-related setsockopt

Fixes: 717e79c8 ("mptcp: Add setsockopt()/getsockopt() socket operations")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After the previous patch we can easily avoid invoking
the workqueue to perform the retransmission, if the
msk socket lock is held at rtx timer expiration.

This also simplifies the relevant code.
Co-developed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The MPTCP_PUSH_PENDING define is 6 and these tests should be testing if
BIT(6) is set.

Fixes: c2e6048f ("mptcp: fix race in release_cb")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

__mptcp_clean_una() can free write memory and should wake-up
user-space processes when needed.

When such function is invoked by the MPTCP receive path, the wakeup
is not needed, as the TCP stack will later trigger subflow_write_space
which will do the wakeup as needed.

Other __mptcp_clean_una() call sites need an additional wakeup check
Let's bundle the relevant code in a new helper and use it.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/165
Fixes: 6e628cd3 ("mptcp: use mptcp release_cb for delayed tasks")
Fixes: 64b9cea7 ("mptcp: fix spurious retransmissions")
Tested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If we receive a MPTCP_PUSH_PENDING even from a subflow when
mptcp_release_cb() is serving the previous one, the latter
will be delayed up to the next release_sock(msk).

Address the issue implementing a test/serve loop for such
event.

Additionally rename the push helper to __mptcp_push_pending()
to be more consistent with the existing code.

Fixes: 6e628cd3 ("mptcp: use mptcp release_cb for delayed tasks")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Will simplify the following patch, no functional change
intended.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Just like with last_snd, we have to NULL 'first' on subflow close.

ack_hint isn't strictly required (its never dereferenced), but better to
clear this explicitly as well instead of making it an exception.

msk->first is dereferenced unconditionally at accept time, but
at that point the ssk is not on the conn_list yet -- this means
worker can't see it when iterating the conn_list.
Reported-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Christoph Paasch reported following crash:
dst_release underflow
WARNING: CPU: 0 PID: 1319 at net/core/dst.c:175 dst_release+0xc1/0xd0 net/core/dst.c:175
CPU: 0 PID: 1319 Comm: syz-executor217 Not tainted 5.11.0-rc6af8e85128b4d0d24083c5cac646e891227052e0c #70
Call Trace:
 rt_cache_route+0x12e/0x140 net/ipv4/route.c:1503
 rt_set_nexthop.constprop.0+0x1fc/0x590 net/ipv4/route.c:1612
 __mkroute_output net/ipv4/route.c:2484 [inline]
...

The worker leaves msk->subflow alone even when it
happened to close the subflow ssk associated with it.

Fixes: 866f26f2 ("mptcp: always graft subflow socket to parent")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/157Reported-by: NChristoph Paasch <cpaasch@apple.com>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of memory pressure the MPTCP xmit path keeps
at most a single skb in the tx cache, eventually freeing
additional ones.

The associated counter for forward memory is not update
accordingly, and that causes the following splat:

WARNING: CPU: 0 PID: 12 at net/core/stream.c:208 sk_stream_kill_queues+0x3ca/0x530 net/core/stream.c:208
Modules linked in:
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.11.0-rc2 #59
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Workqueue: events mptcp_worker
RIP: 0010:sk_stream_kill_queues+0x3ca/0x530 net/core/stream.c:208
Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 63 01 00 00 8b ab 00 01 00 00 e9 60 ff ff ff e8 2f 24 d3 fe 0f 0b eb 97 e8 26 24 d3 fe <0f> 0b eb a0 e8 1d 24 d3 fe 0f 0b e9 a5 fe ff ff 4c 89 e7 e8 0e d0
RSP: 0018:ffffc900000c7bc8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88810030ac40 RSI: ffffffff8262ca4a RDI: 0000000000000003
RBP: 0000000000000d00 R08: 0000000000000000 R09: ffffffff85095aa7
R10: ffffffff8262c9ea R11: 0000000000000001 R12: ffff888108908100
R13: ffffffff85095aa0 R14: ffffc900000c7c48 R15: 1ffff92000018f85
FS:  0000000000000000(0000) GS:ffff88811b200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa7444baef8 CR3: 0000000035ee9005 CR4: 0000000000170ef0
Call Trace:
 __mptcp_destroy_sock+0x4a7/0x6c0 net/mptcp/protocol.c:2547
 mptcp_worker+0x7dd/0x1610 net/mptcp/protocol.c:2272
 process_one_work+0x896/0x1170 kernel/workqueue.c:2275
 worker_thread+0x605/0x1350 kernel/workqueue.c:2421
 kthread+0x344/0x410 kernel/kthread.c:292
 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296

At close time, as reported by syzkaller/Christoph.

This change address the issue properly updating the fwd
allocated memory counter in the error path.
Reported-by: NChristoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/136
Fixes: 724cfd2e ("mptcp: allocate TX skbs in msk context")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Send logic caches last active subflow in the msk, so it needs to be
cleared when the cached subflow is closed.

Fixes: d5f49190 ("mptcp: allow picking different xmit subflows")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/155Reported-by: NChristoph Paasch <cpaasch@apple.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

mptcp re-used inet(6)_release, so the subflow sockets are ignored.
Need to invoke ip(v6)_mc_drop_socket function to ensure mcast join
resources get free'd.

Fixes: 717e79c8 ("mptcp: Add setsockopt()/getsockopt() socket operations")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/110Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Currently we move orphaned msk sockets directly from FIN_WAIT2
state to CLOSE, with the rationale that incoming additional
data could be just dropped by the TCP stack/TW sockets.

Anyhow we miss sending MPTCP-level ack on incoming DATA_FIN,
and that may hang the peers.

Fixes: e16163b6 ("mptcp: refactor shutdown and close")
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Allow userspace (mptcpd) to subscribe to mptcp genl multicast events.
This implementation reuses the same event API as the mptcp kernel fork
to ease integration of existing tools, e.g. mptcpd.

Supported events include:
1. start and close of an mptcp connection
2. start and close of subflows (joins)
3. announce and withdrawals of addresses
4. subflow priority (backup/non-backup) change.
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Once event support is added this may need to allocate memory while msk
lock is held with softirqs disabled.

Not using lock_fast also allows to do the allocation with GFP_KERNEL.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pass the first/initial subflow to the existing functions so they can
pass this on to the notification handler that is added later in the
series.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>