As reported by Maxim, we have a lot of MPTCP-level
retransmissions when multilple links with different latencies
are in use.

This patch refactor the mptcp-level timeout accounting so that
the maximum of all the active subflow timeout is used. To avoid
traversing the subflow list multiple times, the update is
performed inside the packet scheduler.

Additionally clean-up a bit timeout handling.
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>

kfree_rcu() had been removed from pm_netlink.c, so this rcu field in
struct mptcp_pm_addr_entry became useless. Let's drop it.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/20210802231914.54709-1-mathew.j.martineau@linux.intel.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

It has 'if (err >0 )' statement in nlmsg_unicast(), so use nlmsg_unicast()
instead of netlink_unicast(), this looks more concise.

v2: remove the change in netfilter.
Signed-off-by: NYajun Deng <yajun.deng@linux.dev>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After commit 87952603 ("mptcp: protect the rx path with
the msk socket spinlock") the rmem currently used by a given
msk is really sk_rmem_alloc - rmem_released.

The safety check in mptcp_data_ready() does not take the above
in due account, as a result legit incoming data is kept in
subflow receive queue with no reason, delaying or blocking
MPTCP-level ack generation.

This change addresses the issue introducing a new helper to fetch
the rmem memory and using it as needed. Additionally add a MIB
counter for the exceptional event described above - the peer is
misbehaving.

Finally, introduce the required annotation when rmem_released is
updated.

Fixes: 87952603 ("mptcp: protect the rx path with the msk socket spinlock")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/211Signed-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 check_fully_established() causes a subflow reset, it should not
continue to process the packet in tcp_data_queue().
Add a return value to mptcp_incoming_options(), and return false if a
subflow has been reset, else return true. Then drop the packet in
tcp_data_queue()/tcp_rcv_state_process() if mptcp_incoming_options()
return false.

Fixes: d5824847 ("mptcp: fix fallback for MP_JOIN subflows")
Signed-off-by: NJianguo Wu <wujianguo@chinatelecom.cn>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Lots of "TCP: tcp_fin: Impossible, sk->sk_state=7" in client side
when doing stress testing using wrk and webfsd.

There are at least two cases may trigger this warning:
1.mptcp is in syncookie, and server recv MP_JOIN SYN request,
  in subflow_check_req(), the mptcp_can_accept_new_subflow()
  return false, so subflow_init_req_cookie_join_save() isn't
  called, i.e. not store the data present in the MP_JOIN syn
  request and the random nonce in hash table - join_entries[],
  but still send synack. When recv 3rd-ack,
  mptcp_token_join_cookie_init_state() will return false, and
  3rd-ack is dropped, then if mptcp conn is closed by client,
  client will send a DATA_FIN and a MPTCP FIN, the DATA_FIN
  doesn't have MP_CAPABLE or MP_JOIN,
  so mptcp_subflow_init_cookie_req() will return 0, and pass
  the cookie check, MP_JOIN request is fallback to normal TCP.
  Server will send a TCP FIN if closed, in client side,
  when process TCP FIN, it will do reset, the code path is:
    tcp_data_queue()->mptcp_incoming_options()
      ->check_fully_established()->mptcp_subflow_reset().
  mptcp_subflow_reset() will set sock state to TCP_CLOSE,
  so tcp_fin will hit TCP_CLOSE, and print the warning.

2.mptcp is in syncookie, and server recv 3rd-ack, in
  mptcp_subflow_init_cookie_req(), mptcp_can_accept_new_subflow()
  return false, and subflow_req->mp_join is not set to 1,
  so in subflow_syn_recv_sock() will not reset the MP_JOIN
  subflow, but fallback to normal TCP, and then the same thing
  happens when server will send a TCP FIN if closed.

For case1, subflow_check_req() return -EPERM,
then tcp_conn_request() will drop MP_JOIN SYN.

For case2, let subflow_syn_recv_sock() call
mptcp_can_accept_new_subflow(), and do fatal fallback, send reset.

Fixes: 9466a1cc ("mptcp: enable JOIN requests even if cookies are in use")
Signed-off-by: NJianguo Wu <wujianguo@chinatelecom.cn>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In subflow_check_req(), if subflow sport is mismatch, will put msk,
destroy token, and destruct req, then return -EPERM, which can be
done by subflow_req_destructor() via:

  tcp_conn_request()
    |--__reqsk_free()
      |--subflow_req_destructor()

So we should remove these redundant code, otherwise will call
tcp_v4_reqsk_destructor() twice, and may double free
inet_rsk(req)->ireq_opt.

Fixes: 5bc56388 ("mptcp: add port number check for MP_JOIN")
Signed-off-by: NJianguo Wu <wujianguo@chinatelecom.cn>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I did stress test with wrk[1] and webfsd[2] with the assistance of
mptcp-tools[3]:

  Server side:
      ./use_mptcp.sh webfsd -4 -R /tmp/ -p 8099
  Client side:
      ./use_mptcp.sh wrk -c 200 -d 30 -t 4 http://192.168.174.129:8099/

and got the following warning message:

[   55.552626] TCP: request_sock_subflow: Possible SYN flooding on port 8099. Sending cookies.  Check SNMP counters.
[   55.553024] ------------[ cut here ]------------
[   55.553027] WARNING: CPU: 0 PID: 10 at net/core/flow_dissector.c:984 __skb_flow_dissect+0x280/0x1650
...
[   55.553117] CPU: 0 PID: 10 Comm: ksoftirqd/0 Not tainted 5.12.0+ #18
[   55.553121] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020
[   55.553124] RIP: 0010:__skb_flow_dissect+0x280/0x1650
...
[   55.553133] RSP: 0018:ffffb79580087770 EFLAGS: 00010246
[   55.553137] RAX: 0000000000000000 RBX: ffffffff8ddb58e0 RCX: ffffb79580087888
[   55.553139] RDX: ffffffff8ddb58e0 RSI: ffff8f7e4652b600 RDI: 0000000000000000
[   55.553141] RBP: ffffb79580087858 R08: 0000000000000000 R09: 0000000000000008
[   55.553143] R10: 000000008c622965 R11: 00000000d3313a5b R12: ffff8f7e4652b600
[   55.553146] R13: ffff8f7e465c9062 R14: 0000000000000000 R15: ffffb79580087888
[   55.553149] FS:  0000000000000000(0000) GS:ffff8f7f75e00000(0000) knlGS:0000000000000000
[   55.553152] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   55.553154] CR2: 00007f73d1d19000 CR3: 0000000135e10004 CR4: 00000000003706f0
[   55.553160] Call Trace:
[   55.553166]  ? __sha256_final+0x67/0xd0
[   55.553173]  ? sha256+0x7e/0xa0
[   55.553177]  __skb_get_hash+0x57/0x210
[   55.553182]  subflow_init_req_cookie_join_save+0xac/0xc0
[   55.553189]  subflow_check_req+0x474/0x550
[   55.553195]  ? ip_route_output_key_hash+0x67/0x90
[   55.553200]  ? xfrm_lookup_route+0x1d/0xa0
[   55.553207]  subflow_v4_route_req+0x8e/0xd0
[   55.553212]  tcp_conn_request+0x31e/0xab0
[   55.553218]  ? selinux_socket_sock_rcv_skb+0x116/0x210
[   55.553224]  ? tcp_rcv_state_process+0x179/0x6d0
[   55.553229]  tcp_rcv_state_process+0x179/0x6d0
[   55.553235]  tcp_v4_do_rcv+0xaf/0x220
[   55.553239]  tcp_v4_rcv+0xce4/0xd80
[   55.553243]  ? ip_route_input_rcu+0x246/0x260
[   55.553248]  ip_protocol_deliver_rcu+0x35/0x1b0
[   55.553253]  ip_local_deliver_finish+0x44/0x50
[   55.553258]  ip_local_deliver+0x6c/0x110
[   55.553262]  ? ip_rcv_finish_core.isra.19+0x5a/0x400
[   55.553267]  ip_rcv+0xd1/0xe0
...

After debugging, I found in __skb_flow_dissect(), skb->dev and skb->sk
are both NULL, then net is NULL, and trigger WARN_ON_ONCE(!net),
actually net is always NULL in this code path, as skb->dev is set to
NULL in tcp_v4_rcv(), and skb->sk is never set.

Code snippet in __skb_flow_dissect() that trigger warning:
  975         if (skb) {
  976                 if (!net) {
  977                         if (skb->dev)
  978                                 net = dev_net(skb->dev);
  979                         else if (skb->sk)
  980                                 net = sock_net(skb->sk);
  981                 }
  982         }
  983
  984         WARN_ON_ONCE(!net);

So, using seq and transport header derived hash.

[1] https://github.com/wg/wrk
[2] https://github.com/ourway/webfsd
[3] https://github.com/pabeni/mptcp-tools

Fixes: 9466a1cc ("mptcp: enable JOIN requests even if cookies are in use")
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Suggested-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NJianguo Wu <wujianguo@chinatelecom.cn>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since PTP virtual clock support is added, there can be
several PTP virtual clocks based on one PTP physical
clock for timestamping.

This patch is to extend SO_TIMESTAMPING API to support
PHC (PTP Hardware Clock) binding by adding a new flag
SOF_TIMESTAMPING_BIND_PHC. When PTP virtual clocks are
in use, user space can configure to bind one for
timestamping, but PTP physical clock is not supported
and not needed to bind.

This patch is preparation for timestamp conversion from
raw timestamp to a specific PTP virtual clock time in
core net.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Split timestamping handling into a new function
mptcp_setsockopt_sol_socket_timestamping().
This is preparation for extending SO_TIMESTAMPING
for PHC binding, since optval will no longer be
integer.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces a function wrapper to call the sk_error_report
callback. That will prepare to add additional handling whenever
sk_error_report is called, for example to trace socket errors.
Signed-off-by: NAlexander Aring <aahringo@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dan Carpenter reported an issue introduced in
commit fde56eea ("mptcp: refine mptcp_cleanup_rbuf") where a new
boolean (ack_pending) is masked with 0x9.

This is not the intention to ignore values by using a boolean. This
variable should not have a 'bool' type: we should keep the 'u8' to allow
this comparison.

Fixes: fde56eea ("mptcp: refine mptcp_cleanup_rbuf")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current cleanup rbuf tries a bit too hard to avoid acquiring
the subflow socket lock. We may end-up delaying the needed ack,
or skip acking a blocked subflow.

Address the above extending the conditions used to trigger the cleanup
to reflect more closely what TCP does and invoking tcp_cleanup_rbuf()
on all the active subflows.

Note that we can't replicate the exact tests implemented in
tcp_cleanup_rbuf(), as MPTCP lacks some of the required info - e.g.
ping-pong mode.
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 patch added a new flag named deny_join_id0 in struct
mptcp_options_received. Set it when MP_CAPABLE with the flag
MPTCP_CAP_DENYJOIN_ID0 is received.

Also add a new flag remote_deny_join_id0 in struct mptcp_pm_data. When the
flag deny_join_id0 is set, set this remote_deny_join_id0 flag.

In mptcp_pm_create_subflow_or_signal_addr, if the remote_deny_join_id0 flag
is set, and the remote address id is zero, stop this connection.
Suggested-by: NFlorian Westphal <fw@strlen.de>
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 defined a new flag MPTCP_CAP_DENY_JOIN_ID0 for the third bit,
labeled "C" of the MP_CAPABLE option.

Add a new flag allow_join_id0 in struct mptcp_out_options. If this flag is
set, send out the MP_CAPABLE option with the flag MPTCP_CAP_DENY_JOIN_ID0.
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 added a new sysctl, named allow_join_initial_addr_port, to
control whether allow peers to send join requests to the IP address and
port number used by the initial subflow.
Suggested-by: NFlorian Westphal <fw@strlen.de>
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>

commit 78962489 ("mptcp: add skeleton to sync msk socket
options to subflows") introduced a duplicate declaration of
mptcp_setsockopt(), just drop it.
Reported-by: NFlorian Westphal <fw@strlen.de>
Fixes: 78962489 ("mptcp: add skeleton to sync msk socket options to subflows")
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 msk socket state is currently updated in a few spots without
owning the msk socket lock itself.

Some of such operations are safe, as they happens before exposing
the msk socket to user-space and can't race with other changes.

A couple of them, at connect time, can actually race with close()
or shutdown(), leaving breaking the socket state machine.

This change addresses the issue moving such update under the msk
socket lock with the usual:

<acquire spinlock>
<check sk lock onwers>
<ev defer to release_cb>

scheme.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/56
Fixes: 8fd73804 ("mptcp: fallback in case of simultaneous connect")
Fixes: c3c123d1 ("net: mptcp: don't hang in mptcp_sendmsg() after TCP fallback")
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>

Account this exceptional events for better introspection.
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>

Currently we check the msk state to avoid enqueuing new
skbs at msk shutdown time.

Such test is racy - as we can't acquire the msk socket lock -
and useless, as the caller already checked the subflow
field 'disposable', covering the same scenario in a race
free manner - read and updated under the ssk socket lock.
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 don't flush entirely the receive queue, we need set
again such bit later. We can simply avoid clearing it.
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>

There are a bunch of callsite where the ssk socket
lock is acquired using the full-blown version eligible for
the fast variant. Let's move to the latter.
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 mentioned cache was introduced to reduce the number of skb
allocation in atomic context, but the required complexity is
excessive.

This change remove the mentioned cache.
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 current implementation of 32 bit DSN expansion is buggy.
After the previous patch, we can simply reuse the newly
introduced helper to do the expansion safely.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/120
Fixes: 648ef4b8 ("mptcp: Implement MPTCP receive path")
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>

When receiving 32 bits DSS ack from the peer, the MPTCP need
to expand them to 64 bits value. The current code is buggy
WRT detecting 32 bits ack wrap-around: when the wrap-around
happens the current unsigned 32 bit ack value is lower than
the previous one.

Additionally check for possible reverse wrap and make the helper
visible, so that we could re-use it for the next patch.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/204
Fixes: cc9d2566 ("mptcp: update per unacked sequence on pkt reception")
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>

This patch added a new sysctl, named checksum_enabled, to control
whether DSS checksum can be enabled.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Co-developed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-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>

This patch added the mib for the data checksum, MPTCP_MIB_DATACSUMERR.
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>

If the MPTCP-level checksum is enabled, on re-injections we
must spool a complete DSS, or the receive side will not be
able to compute the csum and process any data.
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 patch added three new members named data_csum, csum_len and
map_csum in struct mptcp_subflow_context, implemented a new function
named mptcp_validate_data_checksum().

If the current mapping is valid and csum is enabled traverse the later
pending skbs and compute csum incrementally till the whole mapping has
been covered. If not enough data is available in the rx queue, return
MAPPING_EMPTY - that is, no data.

Next subflow_data_ready invocation will trigger again csum computation.

When the full DSS is available, validate the csum and return to the
caller an appropriate error code, to trigger subflow reset of fallback
as required by the RFC.

Additionally:
- if the csum prevence in the DSS don't match the negotiated value e.g.
  csum present, but not requested, return invalid mapping to trigger
  subflow reset.
- keep some csum state, to avoid re-compute the csum on the same data
  when multiple rx queue traversal are required.
- clean-up the uncompleted mapping from the receive queue on close, to
  allow proper subflow disposal
Co-developed-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
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>

In mptcp_parse_option, adjust the expected_opsize, and always parse the
data checksum value from the receiving DSS regardless of csum presence.
Then save it in mp_opt->csum.
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 in struct mptcp_options_received.

When parsing the MP_CAPABLE with data, if the checksum is enabled,
adjust the expected_opsize. If the receiving option length matches the
length with the data checksum, get the checksum value and save it in
mp_opt->csum. And in mptcp_incoming_options, pass it to mpext->csum.

We always parse any csum/nocsum combination and delay the presence check
to later code, to allow reset if missing.

Additionally, in the TX path, use the newly introduce ext field to avoid
MPTCP csum recomputation on TCP retransmission and unneeded csum update
on when setting the data fin_flag.
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 flag csum_reqd in struct mptcp_options_received, if
the flag MPTCP_CAP_CHECKSUM_REQD is set in the receiving MP_CAPABLE
suboption, set this flag.

In mptcp_sk_clone and subflow_finish_connect, if the csum_reqd flag is set,
enable the msk->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 patch added a new parameter name sk in mptcp_get_options().
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>

In mptcp_write_options, if the checksum is enabled, adjust the option
length and send out the data checksum with DSS suboption.
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>

If the checksum is enabled, send out the data checksum with the
MP_CAPABLE suboption with data.

In mptcp_established_options_mp, save the data checksum in
opts->ext_copy.csum. In mptcp_write_options, adjust the option length and
send it out with the MP_CAPABLE suboption.
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 csum_reqd in struct mptcp_out_options and
struct mptcp_subflow_request_sock. Initialized it with the helper
function mptcp_is_checksum_enabled().

In mptcp_write_options, if this field is enabled, send out the MP_CAPABLE
suboption with the MPTCP_CAP_CHECKSUM_REQD 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 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>

Maxim reported a soft lookup in subflow_error_report():

 watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0]
 RIP: 0010:native_queued_spin_lock_slowpath
 RSP: 0018:ffffa859c0003bc0 EFLAGS: 00000202
 RAX: 0000000000000101 RBX: 0000000000000001 RCX: 0000000000000000
 RDX: ffff9195c2772d88 RSI: 0000000000000000 RDI: ffff9195c2772d88
 RBP: ffff9195c2772d00 R08: 00000000000067b0 R09: c6e31da9eb1e44f4
 R10: ffff9195ef379700 R11: ffff9195edb50710 R12: ffff9195c2772d88
 R13: ffff9195f500e3d0 R14: ffff9195ef379700 R15: ffff9195ef379700
 FS:  0000000000000000(0000) GS:ffff91961f400000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 000000c000407000 CR3: 0000000002988000 CR4: 00000000000006f0
 Call Trace:
  <IRQ>
 _raw_spin_lock_bh
 subflow_error_report
 mptcp_subflow_data_available
 __mptcp_move_skbs_from_subflow
 mptcp_data_ready
 tcp_data_queue
 tcp_rcv_established
 tcp_v4_do_rcv
 tcp_v4_rcv
 ip_protocol_deliver_rcu
 ip_local_deliver_finish
 __netif_receive_skb_one_core
 netif_receive_skb
 rtl8139_poll 8139too
 __napi_poll
 net_rx_action
 __do_softirq
 __irq_exit_rcu
 common_interrupt
  </IRQ>

The calling function - mptcp_subflow_data_available() - can be invoked
from different contexts:
- plain ssk socket lock
- ssk socket lock + mptcp_data_lock
- ssk socket lock + mptcp_data_lock + msk socket lock.

Since subflow_error_report() tries to acquire the mptcp_data_lock, the
latter two call chains will cause soft lookup.

This change addresses the issue moving the error reporting call to
outer functions, where the held locks list is known and the we can
acquire only the needed one.
Reported-by: NMaxim Galaganov <max@internet.ru>
Fixes: 15cc1045 ("mptcp: deliver ssk errors to msk")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/199Signed-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>

warn_bad_map() produces a kernel WARN on bad input coming
from the network. Use pr_debug() to avoid spamming the system
log.

Additionally, when the right bound check fails, warn_bad_map() reports
the wrong ssn value, let's fix it.

Fixes: 648ef4b8 ("mptcp: Implement MPTCP receive path")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/107Signed-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>