Since commit cfde141e ("mptcp: move option parsing into
mptcp_incoming_options()"), the 3rd function argument is no longer used.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch implemented the retransmition of ADD_ADDR when no ADD_ADDR echo
is received. It added a timer with the announced address. When timeout
occurs, ADD_ADDR will be retransmitted.
Suggested-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a new struct mptcp_pm_add_entry to describe add_addr's entry.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added a new helper named mptcp_destroy_common containing the
shared code between mptcp_destroy() and mptcp_sock_destruct().
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added two new mibs for RM_ADDR, named MPTCP_MIB_RMADDR and
MPTCP_MIB_RMSUBFLOW, when the RM_ADDR suboption is received, increase
the first mib counter, when the local subflow is removed, increase the
second mib counter.
Suggested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Suggested-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch implemented the local subflow removing function,
mptcp_pm_remove_subflow, it simply called mptcp_pm_nl_rm_subflow_received
under the PM spin lock.

We use mptcp_pm_remove_subflow to remove a local subflow, so change it's
argument from remote_id to local_id.

We check subflow->local_id in mptcp_pm_nl_rm_subflow_received to remove
a subflow.
Suggested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Suggested-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch implements the remove announced addr and subflow logic in PM
netlink.

When the PM netlink removes an address, we traverse all the existing msk
sockets to find the relevant sockets.

We add a new list named anno_list in mptcp_pm_data, to record all the
announced addrs. In the traversing, we check if it has been recorded.
If it has been, we trigger the RM_ADDR signal.

We also check if this address is in conn_list. If it is, we remove the
subflow which using this local address.

Since we call mptcp_pm_free_anno_list in mptcp_destroy, we need to move
__mptcp_init_sock before the mptcp_is_enabled check in mptcp_init_sock.
Suggested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Suggested-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The re-check of pm->accept_subflow with pm->lock held was missing, this
patch fixed it.
Suggested-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added two mibs for ADD_ADDR, MPTCP_MIB_ADDADDR for receiving
of the ADD_ADDR suboption with echo-flag=0, and MPTCP_MIB_ECHOADD for
receiving the ADD_ADDR suboption with echo-flag=1.
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
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: NDavid S. Miller <davem@davemloft.net>

When the ADD_ADDR suboption has been received, we need to send out the same
ADD_ADDR suboption with echo-flag=1, and no HMAC.
Suggested-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added the RM_ADDR option parsing logic:

We parsed the incoming options to find if the rm_addr option is received,
and called mptcp_pm_rm_addr_received to schedule PM work to a new status,
named MPTCP_PM_RM_ADDR_RECEIVED.

PM work got this status, and called mptcp_pm_nl_rm_addr_received to handle
it.

In mptcp_pm_nl_rm_addr_received, we closed the subflow matching the rm_id,
and updated PM counter.
Suggested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Suggested-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added a new signal named rm_addr_signal in PM. On outgoing path,
we called mptcp_pm_should_rm_signal to check if rm_addr_signal has been
set. If it has been, we sent out the RM_ADDR option.
Suggested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch renamed addr_signal and the related functions with the explicit
word "add".
Suggested-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Christoph reported an infinite loop in the subflow receive path
under stress condition.

If there are multiple subflows, each of them using a large send
buffer, the delta between the sequence number used by
MPTCP-level retransmission can and the current msk->ack_seq
can be greater than MAX_INT.

In the above scenario, when calling mptcp_subflow_discard_data(),
such delta will be truncated to int, and could result in a negative
number: no bytes will be dropped, and subflow_check_data_avail()
will try again to process the same packet, looping forever.

This change addresses the issue by expanding the 'limit' size to 64
bits, so that overflows are not possible anymore.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/87
Fixes: 6719331c ("mptcp: trigger msk processing even for OoO data")
Reported-and-tested-by: NChristoph Paasch <cpaasch@apple.com>
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>

Fixes coccicheck warnig:
net/mptcp/protocol.c:164:11-18: WARNING: Unsigned expression compared with zero: max_seq > 0

Fixes: ab174ad8 ("mptcp: move ooo skbs into msk out of order queue")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

That is needed to let the subflows announce promptly when new
space is available in the receive buffer.

tcp_cleanup_rbuf() is currently a static function, drop the
scope modifier and add a declaration in the TCP header.
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Update the scheduler to less trivial heuristic: cache
the last used subflow, and try to send on it a reasonably
long burst of data.

When the burst or the subflow send space is exhausted, pick
the subflow with the lower ratio between write space and
send buffer - that is, the subflow with the greater relative
amount of free space.

v1 -> v2:
 - fix 32 bit build breakage due to 64bits div
 - fix checkpath issues (uint64_t -> u64)
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>

Currently the 'backup' attribute of local endpoint
is ignored. Let's use it for the MP_JOIN handshake
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>

So that can be accessed easily from the subflow creation
helper. No functional change intended.
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>

Add a bunch of MPTCP mibs related to MPTCP OoO data
processing.
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>

There is no need to use the tcp_read_sock(), we can
simply drop the skb. Additionally try to look at the
next buffer for in order data.

This both simplifies the code and avoid unneeded indirect
calls.
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>

Add an RB-tree to cope with OoO (at MPTCP level) data.
__mptcp_move_skb() insert into the RB tree "future"
data, eventually coalescing skb as allowed by the
MPTCP DSN.

To simplify sequence accounting, move the DSN inside
the cb.

After successfully enqueuing in sequence data, check
if we can use any data from the RB tree.

Additionally move the data_fin check after spooling
data from the OoO tree, otherwise we could miss shutdown
events.

The RB tree code is copied as verbatim as possible
from tcp_data_queue_ofo(), with a few simplifications
due to the fact that MPTCP doesn't need to cope with
sacks. All bugs here are added by me.
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>

Factor-out existing code, will be re-used by the
next patch.
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>

Let the msk sendbuf track the size of the larger subflow's
send window, so that we ensure mptcp_sendmsg() does not
exceed MPTCP-level send window.

The update is performed just before try to send any data.
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>

This is a prerequisite to allow receiving data from multiple
subflows without re-injection.

Instead of dropping the OoO - "future" data in
subflow_check_data_avail(), call into __mptcp_move_skbs()
and let the msk drop that.

To avoid code duplication factor out the mptcp_subflow_discard_data()
helper.

Note that __mptcp_move_skbs() can now find multiple subflows
with data avail (comprising to-be-discarded data), so must
update the byte counter incrementally.

v1 -> v2:
 - fix checkpatch issues (unsigned -> unsigned int)
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>

This simplify mptcp_subflow_data_available() and will
made follow-up patches simpler.

Additionally remove the unneeded checks on subflow copied_seq:
we always whole skbs out of subflows.
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>

Currently, when checking for the 'msk is writable' condition, we
look at the individual subflows write space.
That works well while we send data via a single subflow, but will
not as soon as we will enable concurrent xmit on multiple subflows.

With this change msk becomes writable when the following conditions
hold:
- the socket has some free write space
- there is at least a subflow with write free space

Additionally we need to set the NOSPACE bit on all subflows
before blocking.
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>

mptcp_pm_nl_get_local_id may be called in interrupt context, so we need to
use GFP_ATOMIC flag to allocate memory to avoid sleeping in atomic context.

[  280.209809] BUG: sleeping function called from invalid context at mm/slab.h:498
[  280.209812] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1680, name: kworker/1:3
[  280.209814] INFO: lockdep is turned off.
[  280.209816] CPU: 1 PID: 1680 Comm: kworker/1:3 Tainted: G        W         5.9.0-rc3-mptcp+ #146
[  280.209818] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[  280.209820] Workqueue: events mptcp_worker
[  280.209822] Call Trace:
[  280.209824]  <IRQ>
[  280.209826]  dump_stack+0x77/0xa0
[  280.209829]  ___might_sleep.cold+0xa6/0xb6
[  280.209832]  kmem_cache_alloc_trace+0x1d1/0x290
[  280.209835]  mptcp_pm_nl_get_local_id+0x23c/0x410
[  280.209840]  subflow_init_req+0x1e9/0x2ea
[  280.209843]  ? inet_reqsk_alloc+0x1c/0x120
[  280.209845]  ? kmem_cache_alloc+0x264/0x290
[  280.209849]  tcp_conn_request+0x303/0xae0
[  280.209854]  ? printk+0x53/0x6a
[  280.209857]  ? tcp_rcv_state_process+0x28f/0x1374
[  280.209859]  tcp_rcv_state_process+0x28f/0x1374
[  280.209864]  ? tcp_v4_do_rcv+0xb3/0x1f0
[  280.209866]  tcp_v4_do_rcv+0xb3/0x1f0
[  280.209869]  tcp_v4_rcv+0xed6/0xfa0
[  280.209873]  ip_protocol_deliver_rcu+0x28/0x270
[  280.209875]  ip_local_deliver_finish+0x89/0x120
[  280.209877]  ip_local_deliver+0x180/0x220
[  280.209881]  ip_rcv+0x166/0x210
[  280.209885]  __netif_receive_skb_one_core+0x82/0x90
[  280.209888]  process_backlog+0xd6/0x230
[  280.209891]  net_rx_action+0x13a/0x410
[  280.209895]  __do_softirq+0xcf/0x468
[  280.209899]  asm_call_on_stack+0x12/0x20
[  280.209901]  </IRQ>
[  280.209903]  ? ip_finish_output2+0x240/0x9a0
[  280.209906]  do_softirq_own_stack+0x4d/0x60
[  280.209908]  do_softirq.part.0+0x2b/0x60
[  280.209911]  __local_bh_enable_ip+0x9a/0xa0
[  280.209913]  ip_finish_output2+0x264/0x9a0
[  280.209916]  ? rcu_read_lock_held+0x4d/0x60
[  280.209920]  ? ip_output+0x7a/0x250
[  280.209922]  ip_output+0x7a/0x250
[  280.209925]  ? __ip_finish_output+0x330/0x330
[  280.209928]  __ip_queue_xmit+0x1dc/0x5a0
[  280.209931]  __tcp_transmit_skb+0xa0f/0xc70
[  280.209937]  tcp_connect+0xb03/0xff0
[  280.209939]  ? lockdep_hardirqs_on_prepare+0xe7/0x190
[  280.209942]  ? ktime_get_with_offset+0x125/0x150
[  280.209944]  ? trace_hardirqs_on+0x1c/0xe0
[  280.209948]  tcp_v4_connect+0x449/0x550
[  280.209953]  __inet_stream_connect+0xbb/0x320
[  280.209955]  ? mark_held_locks+0x49/0x70
[  280.209958]  ? lockdep_hardirqs_on_prepare+0xe7/0x190
[  280.209960]  ? __local_bh_enable_ip+0x6b/0xa0
[  280.209963]  inet_stream_connect+0x32/0x50
[  280.209966]  __mptcp_subflow_connect+0x1fd/0x242
[  280.209972]  mptcp_pm_create_subflow_or_signal_addr+0x2db/0x600
[  280.209975]  mptcp_worker+0x543/0x7a0
[  280.209980]  process_one_work+0x26d/0x5b0
[  280.209984]  ? process_one_work+0x5b0/0x5b0
[  280.209987]  worker_thread+0x48/0x3d0
[  280.209990]  ? process_one_work+0x5b0/0x5b0
[  280.209993]  kthread+0x117/0x150
[  280.209996]  ? kthread_park+0x80/0x80
[  280.209998]  ret_from_fork+0x22/0x30

Fixes: 01cacb00 ("mptcp: add netlink-based PM")
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch set the init remote_id to zero, otherwise it will be a random
number.

Then it added the missing subflow's remote_id setting code both in
__mptcp_subflow_connect and in subflow_ulp_clone.

Fixes: 01cacb00 ("mptcp: add netlink-based PM")
Fixes: ec3edaa7 ("mptcp: Add handling of outgoing MP_JOIN requests")
Fixes: f296234c ("mptcp: Add handling of incoming MP_JOIN requests")
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In mptcp_pm_nl_get_local_id, skc_local is the same as msk_local, so it
always return 0. Thus every subflow's local_id is 0. It's incorrect.

This patch fixed this issue.

Also, we need to ignore the zero address here, like 0.0.0.0 in IPv4. When
we use the zero address as a local address, it means that we can use any
one of the local addresses. The zero address is not a new address, we don't
need to add it to PM, so this patch added a new function address_zero to
check whether an address is the zero address, if it is, we ignore this
address.

Fixes: 01cacb00 ("mptcp: add netlink-based PM")
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no caller in tree any more.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After subflow lock is dropped, more wmem might have been made available.

This fixes a deadlock in mptcp_connect.sh 'mmap' mode: wmem is exhausted.
But as the mptcp socket holds on to already-acked data (for retransmit)
no wakeup will occur.

Using 'goto restart' calls mptcp_clean_una(sk) which will free pages
that have been acked completely in the mean time.

Fixes: fb529e62 ("mptcp: break and restart in case mptcp sndbuf is full")
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

Change places that open-code NLA_POLICY_EXACT_LEN() to
use the macro instead, giving us flexibility in how we
handle the details of the macro.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Acked-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fix wasn't correct: When this function is invoked from the
retransmission worker, the iterator contains garbage and resetting
it causes a crash.

As the work queue should not be performance critical also zero the
msghdr struct.

Fixes: 35759383 "(mptcp: sendmsg: reset iter on error)"
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Once we've copied data from the iterator we need to revert in case we
end up not sending any data.

This bug doesn't trigger with normal 'poll' based tests, because
we only feed a small chunk of data to kernel after poll indicated
POLLOUT.  With blocking IO and large writes this triggers. Receiver
ends up with less data than it should get.

Fixes: 72511aab ("mptcp: avoid blocking in tcp_sendpages")
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With commit b93df08c ("mptcp: explicitly track the fully
established status"), the status of unaccepted mptcp closed in
mptcp_sock_destruct() changes from TCP_SYN_RECV to TCP_ESTABLISHED.

As a result mptcp_sock_destruct() does not perform the proper
cleanup and inet_sock_destruct() will later emit a warn.

Address the issue updating the condition tested in mptcp_sock_destruct().
Also update the related comment.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/66Reported-and-tested-by: NChristoph Paasch <cpaasch@apple.com>
Fixes: b93df08c ("mptcp: explicitly track the fully established status")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Nicolas reported the following oops:

[ 1521.392541] BUG: kernel NULL pointer dereference, address: 00000000000000c0
[ 1521.394189] #PF: supervisor read access in kernel mode
[ 1521.395376] #PF: error_code(0x0000) - not-present page
[ 1521.396607] PGD 0 P4D 0
[ 1521.397156] Oops: 0000 [#1] SMP PTI
[ 1521.398020] CPU: 0 PID: 22986 Comm: kworker/0:2 Not tainted 5.8.0-rc4+ #109
[ 1521.399618] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 1521.401728] Workqueue: events mptcp_worker
[ 1521.402651] RIP: 0010:mptcp_subflow_create_socket+0xf1/0x1c0
[ 1521.403954] Code: 24 08 89 44 24 04 48 8b 7a 18 e8 2a 48 d4 ff 8b 44 24 04 85 c0 75 7a 48 8b 8b 78 02 00 00 48 8b 54 24 08 48 8d bb 80 00 00 00 <48> 8b 89 c0 00 00 00 48 89 8a c0 00 00 00 48 8b 8b 78 02 00 00 8b
[ 1521.408201] RSP: 0000:ffffabc4002d3c60 EFLAGS: 00010246
[ 1521.409433] RAX: 0000000000000000 RBX: ffffa0b9ad8c9a00 RCX: 0000000000000000
[ 1521.411096] RDX: ffffa0b9ae78a300 RSI: 00000000fffffe01 RDI: ffffa0b9ad8c9a80
[ 1521.412734] RBP: ffffa0b9adff2e80 R08: ffffa0b9af02d640 R09: ffffa0b9ad923a00
[ 1521.414333] R10: ffffabc4007139f8 R11: fefefefefefefeff R12: ffffabc4002d3cb0
[ 1521.415918] R13: ffffa0b9ad91fa58 R14: ffffa0b9ad8c9f9c R15: 0000000000000000
[ 1521.417592] FS:  0000000000000000(0000) GS:ffffa0b9af000000(0000) knlGS:0000000000000000
[ 1521.419490] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1521.420839] CR2: 00000000000000c0 CR3: 000000002951e006 CR4: 0000000000160ef0
[ 1521.422511] Call Trace:
[ 1521.423103]  __mptcp_subflow_connect+0x94/0x1f0
[ 1521.425376]  mptcp_pm_create_subflow_or_signal_addr+0x200/0x2a0
[ 1521.426736]  mptcp_worker+0x31b/0x390
[ 1521.431324]  process_one_work+0x1fc/0x3f0
[ 1521.432268]  worker_thread+0x2d/0x3b0
[ 1521.434197]  kthread+0x117/0x130
[ 1521.435783]  ret_from_fork+0x22/0x30

on some unconventional configuration.

The MPTCP protocol is trying to create a subflow for an
unaccepted server socket. That is allowed by the RFC, even
if subflow creation will likely fail.
Unaccepted sockets have still a NULL sk_socket field,
avoid the issue by failing earlier.
Reported-and-tested-by: NNicolas Rybowski <nicolas.rybowski@tessares.net>
Fixes: 7d14b0d2 ("mptcp: set correct vfs info for subflows")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of memory pressure, mptcp_sendmsg() may call
sk_stream_wait_memory() after succesfully xmitting some
bytes. If the latter fails we currently return to the
user-space the error code, ignoring the succeful xmit.

Address the issue always checking for the xmitted bytes
before mptcp_sendmsg() completes.

Fixes: f296234c ("mptcp: Add handling of incoming MP_JOIN requests")
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use mptcp_for_each_subflow in mptcp_stream_accept instead of
open-coding.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>