We can now track fully the fallback status of a given connection via the
relevant mibs, the mentioned helper is redundant. Remove it completely.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250723-net-next-mptcp-track-fallbacks-v1-2-a83cce08f2d5@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add the mibs required to cover the few possible fallback causes still
lacking suck info.
Move the relevant mib increment into the fallback helper, so that no
eventual future fallback operation will miss a paired mib increment.
Additionally track failed fallback via its own mib, such mib is
incremented only when a fallback mandated by the protocol fails - due to
racing subflow creation.
While at the above, rename an existing helper to reduce long lines
problems all along.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250723-net-next-mptcp-track-fallbacks-v1-1-a83cce08f2d5@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We have races similar to the one addressed by the previous patch between
subflow failing and additional subflow creation. They are just harder to
trigger.
The solution is similar. Use a separate flag to track the condition
'socket state prevent any additional subflow creation' protected by the
fallback lock.
The socket fallback makes such flag true, and also receiving or sending
an MP_FAIL option.
The field 'allow_infinite_fallback' is now always touched under the
relevant lock, we can drop the ONCE annotation on write.
Fixes: 478d770008 ("mptcp: send out MP_FAIL when data checksum fails")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250714-net-mptcp-fallback-races-v1-2-391aff963322@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This counter is useful to understand why some paths are rejected, and
not created as expected.
It is incremented when receiving a connection request, if the PM didn't
allow the creation of new subflows.
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250413-net-next-mptcp-sched-mib-sft-misc-v2-5-0f83a4350150@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
subflow_hmac_valid() needs to access the MPTCP socket and the subflow
request, but not the request sock that is passed in argument.
Instead, the subflow request can be directly passed to avoid getting it
via an additional cast.
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250413-net-next-mptcp-sched-mib-sft-misc-v2-4-0f83a4350150@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Recently, during a debugging session using local MPTCP connections, I
noticed MPJoinAckHMacFailure was not zero on the server side. The
counter was in fact incremented when the PM rejected new subflows,
because the 'subflow' limit was reached.
The fix is easy, simply dissociating the two cases: only the HMAC
validation check should increase MPTCP_MIB_JOINACKMAC counter.
Fixes: 4cf8b7e48a ("subflow: introduce and use mptcp_can_accept_new_subflow()")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250407-net-mptcp-hmac-failure-mib-v1-1-3c9ecd0a3a50@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When testing valkey benchmark tool with MPTCP, the kernel panics in
'mptcp_can_accept_new_subflow' because subflow_req->msk is NULL.
Call trace:
mptcp_can_accept_new_subflow (./net/mptcp/subflow.c:63 (discriminator 4)) (P)
subflow_syn_recv_sock (./net/mptcp/subflow.c:854)
tcp_check_req (./net/ipv4/tcp_minisocks.c:863)
tcp_v4_rcv (./net/ipv4/tcp_ipv4.c:2268)
ip_protocol_deliver_rcu (./net/ipv4/ip_input.c:207)
ip_local_deliver_finish (./net/ipv4/ip_input.c:234)
ip_local_deliver (./net/ipv4/ip_input.c:254)
ip_rcv_finish (./net/ipv4/ip_input.c:449)
...
According to the debug log, the same req received two SYN-ACK in a very
short time, very likely because the client retransmits the syn ack due
to multiple reasons.
Even if the packets are transmitted with a relevant time interval, they
can be processed by the server on different CPUs concurrently). The
'subflow_req->msk' ownership is transferred to the subflow the first,
and there will be a risk of a null pointer dereference here.
This patch fixes this issue by moving the 'subflow_req->msk' under the
`own_req == true` conditional.
Note that the !msk check in subflow_hmac_valid() can be dropped, because
the same check already exists under the own_req mpj branch where the
code has been moved to.
Fixes: 9466a1cceb ("mptcp: enable JOIN requests even if cookies are in use")
Cc: stable@vger.kernel.org
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Gang Yan <yangang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250328-net-mptcp-misc-fixes-6-15-v1-1-34161a482a7f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Before this patch, if the checksum was not used, the subflow was only
reset if map_data_len was != 0. If there were no MPTCP options or an
invalid mapping, map_data_len was not set to the data len, and then the
subflow was not reset as it should have been, leaving the MPTCP
connection in a wrong fallback mode.
This map_data_len condition has been introduced to handle the reception
of the infinite mapping. Instead, a new dedicated mapping error could
have been returned and treated as a special case. However, the commit
31bf11de14 ("mptcp: introduce MAPPING_BAD_CSUM") has been introduced
by Paolo Abeni soon after, and backported later on to stable. It better
handle the csum case, and it means the exception for valid_csum_seen in
subflow_can_fallback(), plus this one for the infinite mapping in
subflow_check_data_avail(), are no longer needed.
In other words, the code can be simplified there: a fallback should only
be done if msk->allow_infinite_fallback is set. This boolean is set to
false once MPTCP-specific operations acting on the whole MPTCP
connection vs the initial path have been done, e.g. a second path has
been created, or an MPTCP re-injection -- yes, possible even with a
single subflow. The subflow_can_fallback() helper can then be dropped,
and replaced by this single condition.
This also makes the code clearer: a fallback should only be done if it
is possible to do so.
While at it, no need to set map_data_len to 0 in get_mapping_status()
for the infinite mapping case: it will be set to skb->len just after, at
the end of subflow_check_data_avail(), and not read in between.
Fixes: f8d4bcacff ("mptcp: infinite mapping receiving")
Cc: stable@vger.kernel.org
Reported-by: Chester A. Unal <chester.a.unal@xpedite-tech.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/544
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Tested-by: Chester A. Unal <chester.a.unal@xpedite-tech.com>
Link: https://patch.msgid.link/20250224-net-mptcp-misc-fixes-v1-2-f550f636b435@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When we will move the whole RX path under the msk socket lock, updating
the already queued skb for passive fastopen socket at 3rd ack time will
be extremely painful and race prone
The map_seq for already enqueued skbs is used only to allow correct
coalescing with later data; preventing collapsing to the first skb of
a fastopen connect we can completely remove the
__mptcp_fastopen_gen_msk_ackseq() helper.
Before dropping this helper, a new item had to be added to the
mptcp_skb_cb structure. Because this item will be frequently tested in
the fast path -- almost on every packet -- and because there is free
space there, a single byte is used instead of a bitfield. This micro
optimisation slightly reduces the number of CPU operations to do the
associated check.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250218-net-next-mptcp-rx-path-refactor-v1-2-4a47d90d7998@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Consolidate all the cleanup actions requiring the worker in a single
helper and ensure the dummy data fin creation for fallback socket is
performed only when the tcp rx queue is empty.
There are no functional changes intended, but this will simplify the
next patch, when the tcp rx queue spooling could be delayed at release_cb
time.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250218-net-next-mptcp-rx-path-refactor-v1-1-4a47d90d7998@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The variable has already been assigned in the subflow_create_ctx(),
So we don't need to reassign this variable in the subflow_ulp_clone().
Signed-off-by: MoYuanhao <moyuanhao3676@163.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241106071035.2591-1-moyuanhao3676@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
RFC8684 suggests use of "Middlebox interference (code 0x06)" in case of
fully established subflow that carries data at TCP level with no DSS
sub-option.
This is generally the case when mpext is NULL or mpext->use_map is 0:
use a dedicated value of 'mapping_status' and use it before closing the
socket in subflow_check_data_avail().
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/518
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241021-net-next-mptcp-misc-6-13-v1-4-1ef02746504a@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We introduce the same handling for potential data races with the
'fully_established' flag in subflow as previously done for
msk->fully_established.
Additionally, we make a crucial change: convert the subflow's
'fully_established' from 'bit_field' to 'bool' type. This is
necessary because methods for avoiding data races don't work well
with 'bit_field'. Specifically, the 'READ_ONCE' needs to know
the size of the variable being accessed, which is not supported in
'bit_field'. Also, 'test_bit' expect the address of 'bit_field'.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/516
Signed-off-by: Gang Yan <yangang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241021-net-next-mptcp-misc-6-13-v1-2-1ef02746504a@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As reported by Christoph [1], before this patch, an MPTCP connection was
wrongly reset when a host received a first data packet with MPTCP
options after the 3wHS, but got the next ones without.
According to the MPTCP v1 specs [2], a fallback should happen in this
case, because the host didn't receive a DATA_ACK from the other peer,
nor receive data for more than the initial window which implies a
DATA_ACK being received by the other peer.
The patch here re-uses the same logic as the one used in other places:
by looking at allow_infinite_fallback, which is disabled at the creation
of an additional subflow. It's not looking at the first DATA_ACK (or
implying one received from the other side) as suggested by the RFC, but
it is in continuation with what was already done, which is safer, and it
fixes the reported issue. The next step, looking at this first DATA_ACK,
is tracked in [4].
This patch has been validated using the following Packetdrill script:
0 socket(..., SOCK_STREAM, IPPROTO_MPTCP) = 3
+0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+0 bind(3, ..., ...) = 0
+0 listen(3, 1) = 0
// 3WHS is OK
+0.0 < S 0:0(0) win 65535 <mss 1460, sackOK, nop, nop, nop, wscale 6, mpcapable v1 flags[flag_h] nokey>
+0.0 > S. 0:0(0) ack 1 <mss 1460, nop, nop, sackOK, nop, wscale 8, mpcapable v1 flags[flag_h] key[skey]>
+0.1 < . 1:1(0) ack 1 win 2048 <mpcapable v1 flags[flag_h] key[ckey=2, skey]>
+0 accept(3, ..., ...) = 4
// Data from the client with valid MPTCP options (no DATA_ACK: normal)
+0.1 < P. 1:501(500) ack 1 win 2048 <mpcapable v1 flags[flag_h] key[skey, ckey] mpcdatalen 500, nop, nop>
// From here, the MPTCP options will be dropped by a middlebox
+0.0 > . 1:1(0) ack 501 <dss dack8=501 dll=0 nocs>
+0.1 read(4, ..., 500) = 500
+0 write(4, ..., 100) = 100
// The server replies with data, still thinking MPTCP is being used
+0.0 > P. 1:101(100) ack 501 <dss dack8=501 dsn8=1 ssn=1 dll=100 nocs, nop, nop>
// But the client already did a fallback to TCP, because the two previous packets have been received without MPTCP options
+0.1 < . 501:501(0) ack 101 win 2048
+0.0 < P. 501:601(100) ack 101 win 2048
// The server should fallback to TCP, not reset: it didn't get a DATA_ACK, nor data for more than the initial window
+0.0 > . 101:101(0) ack 601
Note that this script requires Packetdrill with MPTCP support, see [3].
Fixes: dea2b1ea9c ("mptcp: do not reset MP_CAPABLE subflow on mapping errors")
Cc: stable@vger.kernel.org
Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/518 [1]
Link: https://datatracker.ietf.org/doc/html/rfc8684#name-fallback [2]
Link: https://github.com/multipath-tcp/packetdrill [3]
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/519 [4]
Reviewed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241008-net-mptcp-fallback-fixes-v1-3-c6fb8e93e551@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Bugged peer implementation can send corrupted DSS options, consistently
hitting a few warning in the data path. Use DEBUG_NET assertions, to
avoid the splat on some builds and handle consistently the error, dumping
related MIBs and performing fallback and/or reset according to the
subflow type.
Fixes: 6771bfd9ee ("mptcp: update mptcp ack sequence from work queue")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241008-net-mptcp-fallback-fixes-v1-1-c6fb8e93e551@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
An MPTCP firewall blackhole can be detected if the following SYN
retransmission after a fallback to "plain" TCP is accepted.
In case of blackhole, a similar technique to the one in place with TFO
is now used: MPTCP can be disabled for a certain period of time, 1h by
default. This time period will grow exponentially when more blackhole
issues get detected right after MPTCP is re-enabled and will reset to
the initial value when the blackhole issue goes away.
The blackhole period can be modified thanks to a new sysctl knob:
blackhole_timeout. Two new MIB counters help understanding what's
happening:
- 'Blackhole', incremented when a blackhole is detected.
- 'MPCapableSYNTXDisabled', incremented when an MPTCP connection
directly falls back to TCP during the blackhole period.
Because the technique is inspired by the one used by TFO, an important
part of the new code is similar to what can find in tcp_fastopen.c, with
some adaptations to the MPTCP case.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/57
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240909-net-next-mptcp-fallback-x-mpc-v1-3-da7ebb4cd2a3@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Recently, a few issues have been discovered around the creation of
additional subflows. Without these counters, it was difficult to point
out the reason why some subflows were not created as expected.
These counters should have been added earlier, because there is no other
simple ways to extract such information from the kernel, and understand
why subflows have not been created.
While at it, some pr_debug() have been added, just in case the errno
needs to be printed.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/509
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240902-net-next-mptcp-mib-mpjtx-misc-v1-3-d3e0f3773b90@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
__mptcp_subflow_connect() is currently called from the path-managers,
which have all the required information to create subflows. No need to
call the PM again to re-iterate over the list of entries with RCU lock
to get more info.
Instead, it is possible to pass a mptcp_pm_addr_entry structure, instead
of a mptcp_addr_info one. The former contains the ifindex and the flags
that are required when creating the new subflow.
This is a partial revert of commit ee285257a9 ("mptcp: drop flags and
ifindex arguments").
While at it, the local ID can also be set if it is known and 0, to avoid
having to set it in the 'rebuild_header' hook, which will cause a new
iteration of the endpoint entries.
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240902-net-next-mptcp-mib-mpjtx-misc-v1-2-d3e0f3773b90@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
pr_debug() have been added in various places in MPTCP code to help
developers to debug some situations. With the dynamic debug feature, it
is easy to enable all or some of them, and asks users to reproduce
issues with extra debug.
Many of these pr_debug() don't end with a new line, while no 'pr_cont()'
are used in MPTCP code. So the goal was not to display multiple debug
messages on one line: they were then not missing the '\n' on purpose.
Not having the new line at the end causes these messages to be printed
with a delay, when something else needs to be printed. This issue is not
visible when many messages need to be printed, but it is annoying and
confusing when only specific messages are expected, e.g.
# echo "func mptcp_pm_add_addr_echoed +fmp" \
> /sys/kernel/debug/dynamic_debug/control
# ./mptcp_join.sh "signal address"; \
echo "$(awk '{print $1}' /proc/uptime) - end"; \
sleep 5s; \
echo "$(awk '{print $1}' /proc/uptime) - restart"; \
./mptcp_join.sh "signal address"
013 signal address
(...)
10.75 - end
15.76 - restart
013 signal address
[ 10.367935] mptcp:mptcp_pm_add_addr_echoed: MPTCP: msk=(...)
(...)
=> a delay of 5 seconds: printed with a 10.36 ts, but after 'restart'
which was printed at the 15.76 ts.
The 'Fixes' tag here below points to the first pr_debug() used without
'\n' in net/mptcp. This patch could be split in many small ones, with
different Fixes tag, but it doesn't seem worth it, because it is easy to
re-generate this patch with this simple 'sed' command:
git grep -l pr_debug -- net/mptcp |
xargs sed -i "s/\(pr_debug(\".*[^n]\)\(\"[,)]\)/\1\\\n\2/g"
So in case of conflicts, simply drop the modifications, and launch this
command.
Fixes: f870fa0b57 ("mptcp: Add MPTCP socket stubs")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240826-net-mptcp-close-extra-sf-fin-v1-4-905199fe1172@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When a peer decides to close one subflow in the middle of a connection
having multiple subflows, the receiver of the first FIN should accept
that, and close the subflow on its side as well. If not, the subflow
will stay half closed, and would even continue to be used until the end
of the MPTCP connection or a reset from the network.
The issue has not been seen before, probably because the in-kernel
path-manager always sends a RM_ADDR before closing the subflow. Upon the
reception of this RM_ADDR, the other peer will initiate the closure on
its side as well. On the other hand, if the RM_ADDR is lost, or if the
path-manager of the other peer only closes the subflow without sending a
RM_ADDR, the subflow would switch to TCP_CLOSE_WAIT, but that's it,
leaving the subflow half-closed.
So now, when the subflow switches to the TCP_CLOSE_WAIT state, and if
the MPTCP connection has not been closed before with a DATA_FIN, the
kernel owning the subflow schedules its worker to initiate the closure
on its side as well.
This issue can be easily reproduced with packetdrill, as visible in [1],
by creating an additional subflow, injecting a FIN+ACK before sending
the DATA_FIN, and expecting a FIN+ACK in return.
Fixes: 40947e1399 ("mptcp: schedule worker when subflow is closed")
Cc: stable@vger.kernel.org
Link: https://github.com/multipath-tcp/packetdrill/pull/154 [1]
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240826-net-mptcp-close-extra-sf-fin-v1-1-905199fe1172@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When a subflow receives and discards duplicate data, the mptcp
stack assumes that the consumed offset inside the current skb is
zero.
With multiple subflows receiving data simultaneously such assertion
does not held true. As a result the subflow-level copied_seq will
be incorrectly increased and later on the same subflow will observe
a bad mapping, leading to subflow reset.
Address the issue taking into account the skb consumed offset in
mptcp_subflow_discard_data().
Fixes: 04e4cd4f7c ("mptcp: cleanup mptcp_subflow_discard_data()")
Cc: stable@vger.kernel.org
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/501
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
There was a support for signal endpoints, but only when the endpoint's
flag was changed during a connection. If an endpoint with the signal and
backup was already present, the MP_JOIN reply was not containing the
backup flag as expected.
That's confusing to have this inconsistent behaviour. On the other hand,
the infrastructure to set the backup flag in the SYN + ACK + MP_JOIN was
already there, it was just never set before. Now when requesting the
local ID from the path-manager, the backup status is also requested.
Note that when the userspace PM is used, the backup flag can be set if
the local address was already used before with a backup flag, e.g. if
the address was announced with the 'backup' flag, or a subflow was
created with the 'backup' flag.
Fixes: 4596a2c1b7 ("mptcp: allow creating non-backup subflows")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/507
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Without such counters, it is difficult to easily debug issues with MPJ
not having the backup flags on production servers.
This is not strictly a fix, but it eases to validate the following
patches without requiring to take packet traces, to query ongoing
connections with Netlink with admin permissions, or to guess by looking
at the behaviour of the packet scheduler. Also, the modification is self
contained, isolated, well controlled, and the increments are done just
after others, there from the beginning. It looks then safe, and helpful
to backport this.
Fixes: 4596a2c1b7 ("mptcp: allow creating non-backup subflows")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
When sending an MP_JOIN + SYN + ACK, it is possible to mark the subflow
as 'backup' by setting the flag with the same name. Before this patch,
the backup was set if the other peer set it in its MP_JOIN + SYN
request.
It is not correct: the backup flag should be set in the MPJ+SYN+ACK only
if the host asks for it, and not mirroring what was done by the other
peer. It is then required to have a dedicated bit for each direction,
similar to what is done in the subflow context.
Fixes: f296234c98 ("mptcp: Add handling of incoming MP_JOIN requests")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
We used to call it 'master' socket at the early stages of MPTCP
development, but the correct wording is 'MPTCP' socket opposed to 'TCP
subflows': convert the last 3 comments to use a more appropriate term.
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The 'else' statements are not needed here, because their previous 'if'
block ends with a 'return'.
This fixes CheckPatch warnings:
WARNING: else is not generally useful after a break or return
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20240514011335.176158-7-martineau@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch fixes the spelling mistakes in comments.
The changes were generated using codespell and reviewed manually.
eariler -> earlier
greceful -> graceful
Signed-off-by: Shi-Sheng Yang <fourcolor4c@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240502154740.249839-1-fourcolor4c@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since we have mapped every mptcp reset reason definition in enum
sk_rst_reason, introducing a new helper can cover some missing places
where we have already set the subflow->reset_reason.
Note: using SK_RST_REASON_NOT_SPECIFIED is the same as
SK_RST_REASON_MPTCP_RST_EUNSPEC. They are both unknown. So we can convert
it directly.
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
It relies on what reset options in the skb are as rfc8684 says. Reusing
this logic can save us much energy. This patch replaces most of the prior
NOT_SPECIFIED reasons.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Like what we did to passive reset:
only passing possible reset reason in each active reset path.
No functional changes.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Adjust the parameter and support passing reason of reset which
is for now NOT_SPECIFIED. No functional changes.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
tcp_v6_init_req() reads TCP_SKB_CB(skb)->tcp_tw_isn to find
out if the request socket is created by a SYN hitting a TIMEWAIT socket.
This has been buggy for a decade, lets directly pass the information
from tcp_conn_request().
This is a preparatory patch to make the following one easier to review.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The reason codes are handled in two ways nowadays (quoting Mat Martineau):
1. Sending in the MPTCP option on RST packets when there is no subflow
context available (these use subflow_add_reset_reason() and directly call
a TCP-level send_reset function)
2. The "normal" way via subflow->reset_reason. This will propagate to both
the outgoing reset packet and to a local path manager process via netlink
in mptcp_event_sub_closed()
RFC 8684 defines the skb reset reason behaviour which is not required
even though in some places:
A host sends a TCP RST in order to close a subflow or reject
an attempt to open a subflow (MP_JOIN). In order to let the
receiving host know why a subflow is being closed or rejected,
the TCP RST packet MAY include the MP_TCPRST option (Figure 15).
The host MAY use this information to decide, for example, whether
it tries to re-establish the subflow immediately, later, or never.
Since the commit dc87efdb1a ("mptcp: add mptcp reset option support")
introduced this feature about three years ago, we can fully use it.
There remains some places where we could insert reason into skb as
we can see in this patch.
Many thanks to Mat and Paolo for help:)
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Current MPTCP servers increment MPTcpExtMPCapableFallbackACK when they
accept non-MPC connections. As reported by Christoph, this is "surprising"
because the counter might become greater than MPTcpExtMPCapableSYNRX.
MPTcpExtMPCapableFallbackACK counter's name suggests it should only be
incremented when a connection was seen using MPTCP options, then a
fallback to TCP has been done. Let's do that by incrementing it when
the subflow context of an inbound MPC connection attempt is dropped.
Also, update mptcp_connect.sh kselftest, to ensure that the
above MIB does not increment in case a pure TCP client connects to a
MPTCP server.
Fixes: fc518953bc ("mptcp: add and use MIB counter infrastructure")
Cc: stable@vger.kernel.org
Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/449
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240329-upstream-net-20240329-fallback-mib-v1-1-324a8981da48@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The headers net/tcp.h, net/genetlink.h and uapi/linux/mptcp.h are included
in protocol.h already, no need to include them again directly. This patch
removes these duplicate header inclusions.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240305-upstream-net-next-20240304-mptcp-misc-cleanup-v1-1-c436ba5e569b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Similar to the previous patch, address the data race on
remote_id, adding the suitable ONCE annotations.
Fixes: bedee0b561 ("mptcp: address lookup improvements")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The local address id is accessed lockless by the NL PM, add
all the required ONCE annotation. There is a caveat: the local
id can be initialized late in the subflow life-cycle, and its
validity is controlled by the local_id_valid flag.
Remove such flag and encode the validity in the local_id field
itself with negative value before initialization. That allows
accessing the field consistently with a single read operation.
Fixes: 0ee4261a36 ("mptcp: implement mptcp_pm_remove_subflow")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most MPTCP-level related fields are under the mptcp data lock
protection, but are written one-off without such lock at MPC
complete time, both for the client and the server
Leverage the mptcp_propagate_state() infrastructure to move such
initialization under the proper lock client-wise.
The server side critical init steps are done by
mptcp_subflow_fully_established(): ensure the caller properly held the
relevant lock, and avoid acquiring the same lock in the nested scopes.
There are no real potential races, as write access to such fields
is implicitly serialized by the MPTCP state machine; the primary
goal is consistency.
Fixes: d22f4988ff ("mptcp: process MP_CAPABLE data option")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The 'msk->write_seq' and 'msk->snd_nxt' are always updated under
the msk socket lock, except at MPC handshake completiont time.
Builds-up on the previous commit to move such init under the relevant
lock.
There are no known problems caused by the potential race, the
primary goal is consistency.
Fixes: 6d0060f600 ("mptcp: Write MPTCP DSS headers to outgoing data packets")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
mptcp_rcv_space_init() is supposed to happen under the msk socket
lock, but active msk socket does that without such protection.
Leverage the existing mptcp_propagate_state() helper to that extent.
We need to ensure mptcp_rcv_space_init will happen before
mptcp_rcv_space_adjust(), and the release_cb does not assure that:
explicitly check for such condition.
While at it, move the wnd_end initialization out of mptcp_rcv_space_init(),
it never belonged there.
Note that the race does not produce ill effect in practice, but
change allows cleaning-up and defying better the locking model.
Fixes: a6b118febb ("mptcp: add receive buffer auto-tuning")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Both the local and the remote key follow the same locking
schema, put in place the proper ONCE accessors.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
While testing the blamed commit below, I was able to miss (!)
packetdrill failures in the fastopen test-cases.
On passive fastopen the child socket is created by incoming TCP MPC syn,
allow for both MPC_SYN and MPC_ACK header.
Fixes: 724b00c129 ("mptcp: refine opt_mp_capable determination")
Reviewed-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
OPTIONS_MPTCP_MPC is a combination of three flags.
It would be better to be strict about testing what
flag is expected, at least for code readability.
mptcp_parse_option() already makes the distinction.
- subflow_check_req() should use OPTION_MPTCP_MPC_SYN.
- mptcp_subflow_init_cookie_req() should use OPTION_MPTCP_MPC_ACK.
- subflow_finish_connect() should use OPTION_MPTCP_MPC_SYNACK
- subflow_syn_recv_sock should use OPTION_MPTCP_MPC_ACK
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Fixes: 74c7dfbee3 ("mptcp: consolidate in_opt sub-options fields in a bitmask")
Link: https://lore.kernel.org/r/20240111194917.4044654-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
