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2025-10-29mptcp: zero window probe mibPaolo Abeni3-0/+3
Explicitly account for MPTCP-level zero windows probe, to catch hopefully earlier issues alike the one addressed by the previous patch. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Tested-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-4-38ffff5a9ec8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29mptcp: restore window probePaolo Abeni1-1/+6
Since commit 72377ab2d671 ("mptcp: more conservative check for zero probes") the MPTCP-level zero window probe check is always disabled, as the TCP-level write queue always contains at least the newly allocated skb. Refine the relevant check tacking in account that the above condition and that such skb can have zero length. Fixes: 72377ab2d671 ("mptcp: more conservative check for zero probes") Cc: stable@vger.kernel.org Reported-by: Geliang Tang <geliang@kernel.org> Closes: https://lore.kernel.org/d0a814c364e744ca6b836ccd5b6e9146882e8d42.camel@kernel.org Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Tested-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-3-38ffff5a9ec8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29mptcp: fix MSG_PEEK stream corruptionPaolo Abeni1-13/+25
If a MSG_PEEK | MSG_WAITALL read operation consumes all the bytes in the receive queue and recvmsg() need to waits for more data - i.e. it's a blocking one - upon arrival of the next packet the MPTCP protocol will start again copying the oldest data present in the receive queue, corrupting the data stream. Address the issue explicitly tracking the peeked sequence number, restarting from the last peeked byte. Fixes: ca4fb892579f ("mptcp: add MSG_PEEK support") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-2-38ffff5a9ec8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29mptcp: drop bogus optimization in __mptcp_check_push()Paolo Abeni2-8/+5
Accessing the transmit queue without owning the msk socket lock is inherently racy, hence __mptcp_check_push() could actually quit early even when there is pending data. That in turn could cause unexpected tx lock and timeout. Dropping the early check avoids the race, implicitly relaying on later tests under the relevant lock. With such change, all the other mptcp_send_head() call sites are now under the msk socket lock and we can additionally drop the now unneeded annotation on the transmit head pointer accesses. Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-1-38ffff5a9ec8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29tcp: fix too slow tcp_rcvbuf_grow() actionEric Dumazet1-1/+9
While the blamed commits apparently avoided an overshoot, they also limited how fast a sender can increase BDP at each RTT. This is not exactly a revert, we do not add the 16 * tp->advmss cushion we had, and we are keeping the out_of_order_queue contribution. Do the same in mptcp_rcvbuf_grow(). Tested: emulated 50ms rtt (tcp_stream --tcp-tx-delay 50000), cubic 20 second flow. net.ipv4.tcp_rmem set to "4096 131072 67000000" perf record -a -e tcp:tcp_rcvbuf_grow sleep 20 perf script Before: We can see we fail to roughly double RWIN at each RTT. Sender is RWIN limited while CWND is ramping up (before getting tcp_wmem limited). tcp_stream 33793 [010] 825.717525: tcp:tcp_rcvbuf_grow: time=100869 rtt_us=50428 copied=49152 inq=0 space=40960 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=103970 window_clamp=112128 rcv_wnd=106496 tcp_stream 33793 [010] 825.768966: tcp:tcp_rcvbuf_grow: time=51447 rtt_us=50362 copied=86016 inq=0 space=49152 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=107474 window_clamp=112128 rcv_wnd=106496 tcp_stream 33793 [010] 825.821539: tcp:tcp_rcvbuf_grow: time=52577 rtt_us=50243 copied=114688 inq=0 space=86016 ooo=0 scaling_ratio=219 rcvbuf=201096 rcv_ssthresh=167377 window_clamp=172031 rcv_wnd=167936 tcp_stream 33793 [010] 825.871781: tcp:tcp_rcvbuf_grow: time=50248 rtt_us=50237 copied=167936 inq=0 space=114688 ooo=0 scaling_ratio=219 rcvbuf=268129 rcv_ssthresh=224722 window_clamp=229375 rcv_wnd=225280 tcp_stream 33793 [010] 825.922475: tcp:tcp_rcvbuf_grow: time=50698 rtt_us=50183 copied=241664 inq=0 space=167936 ooo=0 scaling_ratio=219 rcvbuf=392617 rcv_ssthresh=331217 window_clamp=335871 rcv_wnd=323584 tcp_stream 33793 [010] 825.973326: tcp:tcp_rcvbuf_grow: time=50855 rtt_us=50213 copied=339968 inq=0 space=241664 ooo=0 scaling_ratio=219 rcvbuf=564986 rcv_ssthresh=478674 window_clamp=483327 rcv_wnd=462848 tcp_stream 33793 [010] 826.023970: tcp:tcp_rcvbuf_grow: time=50647 rtt_us=50248 copied=491520 inq=0 space=339968 ooo=0 scaling_ratio=219 rcvbuf=794811 rcv_ssthresh=671778 window_clamp=679935 rcv_wnd=651264 tcp_stream 33793 [010] 826.074612: tcp:tcp_rcvbuf_grow: time=50648 rtt_us=50227 copied=700416 inq=0 space=491520 ooo=0 scaling_ratio=219 rcvbuf=1149124 rcv_ssthresh=974881 window_clamp=983039 rcv_wnd=942080 tcp_stream 33793 [010] 826.125452: tcp:tcp_rcvbuf_grow: time=50845 rtt_us=50225 copied=987136 inq=8192 space=700416 ooo=0 scaling_ratio=219 rcvbuf=1637502 rcv_ssthresh=1392674 window_clamp=1400831 rcv_wnd=1339392 tcp_stream 33793 [010] 826.175698: tcp:tcp_rcvbuf_grow: time=50250 rtt_us=50198 copied=1347584 inq=0 space=978944 ooo=0 scaling_ratio=219 rcvbuf=2288672 rcv_ssthresh=1949729 window_clamp=1957887 rcv_wnd=1945600 tcp_stream 33793 [010] 826.225947: tcp:tcp_rcvbuf_grow: time=50252 rtt_us=50240 copied=1945600 inq=0 space=1347584 ooo=0 scaling_ratio=219 rcvbuf=3150516 rcv_ssthresh=2687010 window_clamp=2695167 rcv_wnd=2691072 tcp_stream 33793 [010] 826.276175: tcp:tcp_rcvbuf_grow: time=50233 rtt_us=50224 copied=2691072 inq=0 space=1945600 ooo=0 scaling_ratio=219 rcvbuf=4548617 rcv_ssthresh=3883041 window_clamp=3891199 rcv_wnd=3887104 tcp_stream 33793 [010] 826.326403: tcp:tcp_rcvbuf_grow: time=50233 rtt_us=50229 copied=3887104 inq=0 space=2691072 ooo=0 scaling_ratio=219 rcvbuf=6291456 rcv_ssthresh=5370482 window_clamp=5382144 rcv_wnd=5373952 tcp_stream 33793 [010] 826.376723: tcp:tcp_rcvbuf_grow: time=50323 rtt_us=50218 copied=5373952 inq=0 space=3887104 ooo=0 scaling_ratio=219 rcvbuf=9087658 rcv_ssthresh=7755537 window_clamp=7774207 rcv_wnd=7757824 tcp_stream 33793 [010] 826.426991: tcp:tcp_rcvbuf_grow: time=50274 rtt_us=50196 copied=7757824 inq=180224 space=5373952 ooo=0 scaling_ratio=219 rcvbuf=12563759 rcv_ssthresh=10729233 window_clamp=10747903 rcv_wnd=10575872 tcp_stream 33793 [010] 826.477229: tcp:tcp_rcvbuf_grow: time=50241 rtt_us=50078 copied=10731520 inq=180224 space=7577600 ooo=0 scaling_ratio=219 rcvbuf=17715667 rcv_ssthresh=15136529 window_clamp=15155199 rcv_wnd=14983168 tcp_stream 33793 [010] 826.527482: tcp:tcp_rcvbuf_grow: time=50258 rtt_us=50153 copied=15138816 inq=360448 space=10551296 ooo=0 scaling_ratio=219 rcvbuf=24667870 rcv_ssthresh=21073410 window_clamp=21102591 rcv_wnd=20766720 tcp_stream 33793 [010] 826.577712: tcp:tcp_rcvbuf_grow: time=50234 rtt_us=50228 copied=21073920 inq=0 space=14778368 ooo=0 scaling_ratio=219 rcvbuf=34550339 rcv_ssthresh=29517041 window_clamp=29556735 rcv_wnd=29519872 tcp_stream 33793 [010] 826.627982: tcp:tcp_rcvbuf_grow: time=50275 rtt_us=50220 copied=29519872 inq=540672 space=21073920 ooo=0 scaling_ratio=219 rcvbuf=49268707 rcv_ssthresh=42090625 window_clamp=42147839 rcv_wnd=41627648 tcp_stream 33793 [010] 826.678274: tcp:tcp_rcvbuf_grow: time=50296 rtt_us=50185 copied=42053632 inq=761856 space=28979200 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57238168 window_clamp=57316406 rcv_wnd=56606720 tcp_stream 33793 [010] 826.728627: tcp:tcp_rcvbuf_grow: time=50357 rtt_us=50128 copied=43913216 inq=851968 space=41291776 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56524800 tcp_stream 33793 [010] 827.131364: tcp:tcp_rcvbuf_grow: time=50239 rtt_us=50127 copied=43843584 inq=655360 space=43061248 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56696832 tcp_stream 33793 [010] 827.181613: tcp:tcp_rcvbuf_grow: time=50254 rtt_us=50115 copied=43843584 inq=524288 space=43188224 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56807424 tcp_stream 33793 [010] 828.339635: tcp:tcp_rcvbuf_grow: time=50283 rtt_us=50110 copied=43843584 inq=458752 space=43319296 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56864768 tcp_stream 33793 [010] 828.440350: tcp:tcp_rcvbuf_grow: time=50404 rtt_us=50099 copied=43843584 inq=393216 space=43384832 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56922112 tcp_stream 33793 [010] 829.195106: tcp:tcp_rcvbuf_grow: time=50154 rtt_us=50077 copied=43843584 inq=196608 space=43450368 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=57090048 After: It takes few steps to increase RWIN. Sender is no longer RWIN limited. tcp_stream 50826 [010] 935.634212: tcp:tcp_rcvbuf_grow: time=100788 rtt_us=50315 copied=49152 inq=0 space=40960 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=103970 window_clamp=112128 rcv_wnd=106496 tcp_stream 50826 [010] 935.685642: tcp:tcp_rcvbuf_grow: time=51437 rtt_us=50361 copied=86016 inq=0 space=49152 ooo=0 scaling_ratio=219 rcvbuf=160875 rcv_ssthresh=132969 window_clamp=137623 rcv_wnd=131072 tcp_stream 50826 [010] 935.738299: tcp:tcp_rcvbuf_grow: time=52660 rtt_us=50256 copied=139264 inq=0 space=86016 ooo=0 scaling_ratio=219 rcvbuf=502741 rcv_ssthresh=411497 window_clamp=430079 rcv_wnd=413696 tcp_stream 50826 [010] 935.788544: tcp:tcp_rcvbuf_grow: time=50249 rtt_us=50233 copied=307200 inq=0 space=139264 ooo=0 scaling_ratio=219 rcvbuf=728690 rcv_ssthresh=618717 window_clamp=623371 rcv_wnd=618496 tcp_stream 50826 [010] 935.838796: tcp:tcp_rcvbuf_grow: time=50258 rtt_us=50202 copied=618496 inq=0 space=307200 ooo=0 scaling_ratio=219 rcvbuf=2450338 rcv_ssthresh=1855709 window_clamp=2096187 rcv_wnd=1859584 tcp_stream 50826 [010] 935.889140: tcp:tcp_rcvbuf_grow: time=50347 rtt_us=50166 copied=1261568 inq=0 space=618496 ooo=0 scaling_ratio=219 rcvbuf=4376503 rcv_ssthresh=3725291 window_clamp=3743961 rcv_wnd=3706880 tcp_stream 50826 [010] 935.939435: tcp:tcp_rcvbuf_grow: time=50300 rtt_us=50185 copied=2478080 inq=24576 space=1261568 ooo=0 scaling_ratio=219 rcvbuf=9082648 rcv_ssthresh=7733731 window_clamp=7769921 rcv_wnd=7692288 tcp_stream 50826 [010] 935.989681: tcp:tcp_rcvbuf_grow: time=50251 rtt_us=50221 copied=4915200 inq=114688 space=2453504 ooo=0 scaling_ratio=219 rcvbuf=16574936 rcv_ssthresh=14108110 window_clamp=14179339 rcv_wnd=14024704 tcp_stream 50826 [010] 936.039967: tcp:tcp_rcvbuf_grow: time=50289 rtt_us=50279 copied=9830400 inq=114688 space=4800512 ooo=0 scaling_ratio=219 rcvbuf=32695050 rcv_ssthresh=27896187 window_clamp=27969593 rcv_wnd=27815936 tcp_stream 50826 [010] 936.090172: tcp:tcp_rcvbuf_grow: time=50211 rtt_us=50200 copied=19841024 inq=114688 space=9715712 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57245176 window_clamp=57316406 rcv_wnd=57163776 tcp_stream 50826 [010] 936.140430: tcp:tcp_rcvbuf_grow: time=50262 rtt_us=50197 copied=39501824 inq=114688 space=19726336 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57245176 window_clamp=57316406 rcv_wnd=57163776 tcp_stream 50826 [010] 936.190527: tcp:tcp_rcvbuf_grow: time=50101 rtt_us=50071 copied=43655168 inq=262144 space=39387136 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57032704 tcp_stream 50826 [010] 936.240719: tcp:tcp_rcvbuf_grow: time=50197 rtt_us=50057 copied=43843584 inq=262144 space=43393024 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57032704 tcp_stream 50826 [010] 936.341271: tcp:tcp_rcvbuf_grow: time=50297 rtt_us=50123 copied=43843584 inq=131072 space=43581440 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57147392 tcp_stream 50826 [010] 936.642503: tcp:tcp_rcvbuf_grow: time=50131 rtt_us=50084 copied=43843584 inq=0 space=43712512 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57262080 Fixes: 65c5287892e9 ("tcp: fix sk_rcvbuf overshoot") Fixes: e118cdc34dd1 ("mptcp: rcvbuf auto-tuning improvement") Reported-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/589 Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-4-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29tcp: add newval parameter to tcp_rcvbuf_grow()Eric Dumazet1-12/+8
This patch has no functional change, and prepares the following one. tcp_rcvbuf_grow() will need to have access to tp->rcvq_space.space old and new values. Change mptcp_rcvbuf_grow() in a similar way. Signed-off-by: Eric Dumazet <edumazet@google.com> [ Moved 'oldval' declaration to the next patch to avoid warnings at build time. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-3-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29mptcp: fix subflow rcvbuf adjustPaolo Abeni1-2/+6
The mptcp PM can add subflow to the conn_list before tcp_init_transfer(). Calling tcp_rcvbuf_grow() on such subflow is not correct as later init will overwrite the update. Fix the issue calling tcp_rcvbuf_grow() only after init buffer initialization. Fixes: e118cdc34dd1 ("mptcp: rcvbuf auto-tuning improvement") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-1-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-21mptcp: pm: in-kernel: C-flag: handle late ADD_ADDRMatthieu Baerts (NGI0)1-0/+6
The special C-flag case expects the ADD_ADDR to be received when switching to 'fully-established'. But for various reasons, the ADD_ADDR could be sent after the "4th ACK", and the special case doesn't work. On NIPA, the new test validating this special case for the C-flag failed a few times, e.g. 102 default limits, server deny join id 0 syn rx [FAIL] got 0 JOIN[s] syn rx expected 2 Server ns stats (...) MPTcpExtAddAddrTx 1 MPTcpExtEchoAdd 1 Client ns stats (...) MPTcpExtAddAddr 1 MPTcpExtEchoAddTx 1 synack rx [FAIL] got 0 JOIN[s] synack rx expected 2 ack rx [FAIL] got 0 JOIN[s] ack rx expected 2 join Rx [FAIL] see above syn tx [FAIL] got 0 JOIN[s] syn tx expected 2 join Tx [FAIL] see above I had a suspicion about what the issue could be: the ADD_ADDR might have been received after the switch to the 'fully-established' state. The issue was not easy to reproduce. The packet capture shown that the ADD_ADDR can indeed be sent with a delay, and the client would not try to establish subflows to it as expected. A simple fix is not to mark the endpoints as 'used' in the C-flag case, when looking at creating subflows to the remote initial IP address and port. In this case, there is no need to try. Note: newly added fullmesh endpoints will still continue to be used as expected, thanks to the conditions behind mptcp_pm_add_addr_c_flag_case. Fixes: 4b1ff850e0c1 ("mptcp: pm: in-kernel: usable client side with C-flag") 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/20251020-net-mptcp-c-flag-late-add-addr-v1-1-8207030cb0e8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29mptcp: minor move_skbs_to_msk() cleanupPaolo Abeni1-6/+2
Such function is called only by __mptcp_data_ready(), which in turn is always invoked when msk is not owned by the user: we can drop the redundant, related check. Additionally mptcp needs to propagate the socket error only for current subflow. Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250927-net-next-mptcp-rcv-path-imp-v1-7-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29mptcp: factor out a basic skb coalesce helperPaolo Abeni1-6/+17
The upcoming patch will introduced backlog processing for MPTCP socket, and we want to leverage coalescing in such data path. Factor out the relevant bits not touching memory accounting to deal with such use-case. Co-developed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250927-net-next-mptcp-rcv-path-imp-v1-6-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29mptcp: remove unneeded mptcp_move_skb()Paolo Abeni1-7/+1
Since commit b7535cfed223 ("mptcp: drop legacy code around RX EOF"), sk_shutdown can't change during the main recvmsg loop, we can drop the related race breaker. Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250927-net-next-mptcp-rcv-path-imp-v1-5-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29mptcp: introduce the mptcp_init_skb helperPaolo Abeni1-21/+25
Factor out all the skb initialization step in a new helper and use it. Note that this change moves the MPTCP CB initialization earlier: we can do such step as soon as the skb leaves the subflow socket receive queues. Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250927-net-next-mptcp-rcv-path-imp-v1-4-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29mptcp: rcvbuf auto-tuning improvementPaolo Abeni2-52/+49
Apply to the MPTCP auto-tuning the same improvements introduced for the TCP protocol by the merge commit 2da35e4b4df9 ("Merge branch 'tcp-receive-side-improvements'"). The main difference is that TCP subflow and the main MPTCP socket need to account separately for OoO: MPTCP does not care for TCP-level OoO and vice versa, as a consequence do not reflect MPTCP-level rcvbuf increase due to OoO packets at the subflow level. This refeactor additionally allow dropping the msk receive buffer update at receive time, as the latter only intended to cope with subflow receive buffer increase due to OoO packets. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/487 Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/559 Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@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/20250927-net-next-mptcp-rcv-path-imp-v1-3-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29mptcp: leverage skb deferral freePaolo Abeni1-2/+3
Usage of the skb deferral API is straight-forward; with multiple subflows actives this allow moving part of the received application load into multiple CPUs. Also fix a typo in the related comment. Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250927-net-next-mptcp-rcv-path-imp-v1-1-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: add laminar endpointsMatthieu Baerts (NGI0)3-0/+85
Currently, upon the reception of an ADD_ADDR (and when the fullmesh flag is not used), the in-kernel PM will create new subflows using the local address the routing configuration will pick. It would be easier to pick local addresses from a selected list of endpoints, and use it only once, than relying on routing rules. Use case: both the client (C) and the server (S) have two addresses (a and b). The client establishes the connection between C(a) and S(a). Once established, the server announces its additional address S(b). Once received, the client connects to it using its second address C(b). Compared to a situation without the 'laminar' endpoint for C(b), the client didn't use this address C(b) to establish a subflow to the server's primary address S(a). So at the end, we have: C S C(a) --- S(a) C(b) --- S(b) In case of a 3rd address on each side (C(c) and S(c)), upon the reception of an ADD_ADDR with S(c), the client should not pick C(b) because it has already been used. C(c) should then be used. Note that this situation is currently possible if C doesn't add any endpoint, but configure the routing in order to pick C(b) for the route to S(b), and pick C(c) for the route to S(c). That doesn't sound very practical because it means knowing in advance the IP addresses that will be used and announced by the server. 'laminar', like the idea of laminar flows: the different subflows don't mix with each other on an endpoint, unlike the "turbulent" way traffic is mixed by 'fullmesh'. In the code, the new endpoint type is added. Similar to the other subflow types, an MPTCP_INFO counter is added. While at it, hole are now commented in struct mptcp_info, to remember next time that these holes can no longer be used. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/503 Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-15-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: compare IDs instead of addressesMatthieu Baerts (NGI0)1-38/+44
When receiving an ADD_ADDR right after the 3WHS, the connection will switch to 'fully established'. It means the MPTCP worker will be called to treat two events, in this order: ADD_ADDR_RECEIVED, PM_ESTABLISHED. The MPTCP endpoints cannot have the ID 0, because it is reserved to the address and port used by the initial subflow. To be able to deal with this case in different places, msk->mpc_endpoint_id contains the endpoint ID linked to the initial subflow. This variable was only set when treating the first PM_ESTABLISHED event, after ADD_ADDR_RECEIVED. That's why in fill_local_addresses_vec(), the endpoint addresses were compared with the one of the initial subflow, instead of only comparing the IDs. Instead, msk->mpc_endpoint_id is now set when treating ADD_ADDR_RECEIVED as well, if needed, then the IDs can be compared. To be able to do so, the code doing that is now in a dedicated helper, and called from the functions linked to the two actions. While at it, mptcp_endp_get_local_id() has also been moved up, next to this new helper, because they are linked, and to be able to use it in fill_local_addresses_vec() in the next commit. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-14-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: reduce pernet struct sizeMatthieu Baerts (NGI0)2-40/+27
All the 'unsigned int' variables from the 'pm_nl_pernet' structure are bounded to MPTCP_PM_ADDR_MAX, currently set to 8. The endpoint ID is also bounded by the protocol to 8-bit. MPTCP_PM_ADDR_MAX, if extended later, will never over 8-bit. So no need to use 'unsigned int' variables, 'u8' is enough. Note that the exposed counters in MPTCP_INFO are already limited to 8-bit, same for pm->extra_subflows, and others. So it seems even better to limit them to 8-bit. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-13-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: remove stale_loss_cntMatthieu Baerts (NGI0)1-2/+0
It is currently not used. It was in fact never used since its introduction in commit ff5a0b421cb2 ("mptcp: faster active backup recovery"). It was probably initially added to struct pm_nl_pernet during the development of this commit, before being added to struct mptcp_pernet in ctrl.c, but not removed from the first place. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-12-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: rename 'addrs' to 'endpoints'Matthieu Baerts (NGI0)1-6/+6
A few variables linked to the in-kernel Path-Manager are confusing, and it would help current and future developers, to clarify them. One of them is 'addrs', which in fact represents the number of declared endpoints, and not only the 'signal' endpoints. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-11-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: rename 'local_addr_list' to 'endp_list'Matthieu Baerts (NGI0)1-12/+12
A few variables linked to the in-kernel Path-Manager are confusing, and it would help current and future developers, to clarify them. One of them is 'local_addr_list', which in fact represents the list of endpoints, and not only the 'subflow' endpoints. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-10-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: rename 'local_addr_max' to 'endp_subflow_max'Matthieu Baerts (NGI0)4-24/+24
A few variables linked to the in-kernel Path-Manager are confusing, and it would help current and future developers, to clarify them. One of them is 'local_addr_max', which in fact represents the maximum number of 'subflow' endpoints that can be used to create new subflows, and not the number of local addresses that have been used to create subflows. While at it, add an additional name for the corresponding variable in MPTCP INFO: mptcpi_endp_subflow_max. Not to break the current uAPI, the new name is added as a 'define' pointing to the former name. This will then also help userspace devs. Also move the variable and function next to the other 'endp_X_max' ones. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-9-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: rename 'add_addr_accept_max' to 'limit_add_addr_accepted'Matthieu Baerts (NGI0)4-17/+20
A few variables linked to the in-kernel Path-Manager are confusing, and it would help current and future developers, to clarify them. One of them is 'add_addr_accept_max', which in fact represents the limit of ADD_ADDR that can be accepted: the limit set via 'ip mptcp limit add_addr_accepted X' for example. It is not linked to the maximum number of accepted ADD_ADDR. While at it, add an additional name for the corresponding variable in MPTCP INFO: mptcpi_limit_add_addr_accepted. Not to break the current uAPI, the new name is added as a 'define' pointing to the former name. This will then also help userspace devs. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-8-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: rename 'add_addr_signal_max' to 'endp_signal_max'Matthieu Baerts (NGI0)4-17/+17
A few variables linked to the in-kernel Path-Manager are confusing, and it would help current and future developers, to clarify them. One of them is 'add_addr_signal_max', which in fact represents the maximum number of 'signal' endpoints that can be used to announced addresses, and not the number of ADD_ADDR that can be signalled. While at it, add an additional name for the corresponding variable in MPTCP INFO: mptcpi_endp_signal_max. Not to break the current uAPI, the new name is added as a 'define' pointing to the former name. This will then also help userspace devs. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-7-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: rename 'subflows_max' to 'limit_extra_subflows'Matthieu Baerts (NGI0)4-34/+36
A few variables linked to the in-kernel Path-Manager are confusing, and it would help current and future developers, to clarify them. One of them is 'subflows_max', which in fact represents the limit of extra subflows: the limit set via 'ip mptcp limit subflows X' for example. It is not linked to the maximum number of created / possible subflows. While at it, add an additional name for the corresponding variable in MPTCP INFO: mptcpi_limit_extra_subflows. Not to break the current uAPI, the new name is added as a 'define' pointing to the former name. This will then also help userspace devs. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-6-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: rename 'subflows' to 'extra_subflows'Matthieu Baerts (NGI0)5-24/+25
A few variables linked to the Path-Managers are confusing, and it would help current and future developers, to clarify them. One of them is 'subflows', which in fact represents the number of extra subflows: all the additional subflows created after the initial one, and not the total number of subflows. While at it, add an additional name for the corresponding variable in MPTCP INFO: mptcpi_extra_subflows. Not to break the current uAPI, the new name is added as a 'define' pointing to the former name. This will then also help userspace devs. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-5-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: refactor fill_remote_addresses_vecMatthieu Baerts (NGI0)1-49/+67
Before this modification, this function was quite long with many levels of indentations. Each case can be split in a dedicated function: fullmesh, non-fullmesh. To remove one level of indentation, msk->pm.subflows >= subflows_max is now checked after having added one subflow, and stops the loop if it is no longer possible to add new subflows. This is fine to do this because this function should only be called if msk->pm.subflows < subflows_max. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-4-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: refactor fill_local_addresses_vecMatthieu Baerts (NGI0)1-71/+104
Before this modification, this function was quite long with many levels of indentations. Each case can be split in a dedicated function: fullmesh, C flag, any. No functional changes intended. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-3-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-26mptcp: pm: in-kernel: usable client side with C-flagMatthieu Baerts (NGI0)3-3/+62
When servers set the C-flag in their MP_CAPABLE to tell clients not to create subflows to the initial address and port, clients will likely not use their other endpoints. That's because the in-kernel path-manager uses the 'subflow' endpoints to create subflows only to the initial address and port. If the limits have not been modified to accept ADD_ADDR, the client doesn't try to establish new subflows. If the limits accept ADD_ADDR, the routing routes will be used to select the source IP. The C-flag is typically set when the server is operating behind a legacy Layer 4 load balancer, or using anycast IP address. Clients having their different 'subflow' endpoints setup, don't end up creating multiple subflows as expected, and causing some deployment issues. A special case is then added here: when servers set the C-flag in the MPC and directly sends an ADD_ADDR, this single ADD_ADDR is accepted. The 'subflows' endpoints will then be used with this new remote IP and port. This exception is only allowed when the ADD_ADDR is sent immediately after the 3WHS, and makes the client switching to the 'fully established' mode. After that, 'select_local_address()' will not be able to find any subflows, because 'id_avail_bitmap' will be filled in mptcp_pm_create_subflow_or_signal_addr(), when switching to 'fully established' mode. Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received") Cc: stable@vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/536 Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-1-ad126cc47c6b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-22mptcp: remove unused returned value of check_data_finMatthieu Baerts (NGI0)1-4/+1
When working on a fix modifying mptcp_check_data_fin(), I noticed the returned value was no longer used. It looks like it was used for 3 days, between commit 7ed90803a213 ("mptcp: send explicit ack on delayed ack_seq incr") and commit ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling"). This returned value can be safely removed. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-6-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-22mptcp: pm: netlink: deprecate server-side attributeMatthieu Baerts (NGI0)1-1/+1
Now that such info is in the 'flags' attribute, it is time to deprecate the dedicated 'server-side' attribute. It will be removed in a few versions. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-3-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-22mptcp: pm: netlink: announce server-side flagMatthieu Baerts (NGI0)1-4/+7
Now that the 'flags' attribute is used, it seems interesting to add one flag for 'server-side', a boolean value. This is duplicating the info from the dedicated 'server-side' attribute, but it will be deprecated in the next commit, and removed in a few versions. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-2-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-22mptcp: pm: netlink: only add server-side attr when trueMatthieu Baerts (NGI0)1-1/+3
This attribute is a boolean. No need to add it to set it to 'false'. Indeed, the default value when this attribute is not set is naturally 'false'. A few bytes can then be saved by not adding this attribute if the connection is not on the server side. This prepares the future deprecation of its attribute, in favour of a new flag. Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-1-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-19mptcp: reset blackhole on success with non-loopback ifacesMatthieu Baerts (NGI0)1-1/+1
When a first MPTCP connection gets successfully established after a blackhole period, 'active_disable_times' was supposed to be reset when this connection was done via any non-loopback interfaces. Unfortunately, the opposite condition was checked: only reset when the connection was established via a loopback interface. Fixing this by simply looking at the opposite. This is similar to what is done with TCP FastOpen, see tcp_fastopen_active_disable_ofo_check(). This patch is a follow-up of a previous discussion linked to commit 893c49a78d9f ("mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable()."), see [1]. Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/4209a283-8822-47bd-95b7-87e96d9b7ea3@kernel.org [1] Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Simon Horman <horms@kernel.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250918-net-next-mptcp-blackhole-reset-loopback-v1-1-bf5818326639@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski4-3/+30
Cross-merge networking fixes after downstream PR (net-6.17-rc7). No conflicts. Adjacent changes: drivers/net/ethernet/mellanox/mlx5/core/en/fs.h 9536fbe10c9d ("net/mlx5e: Add PSP steering in local NIC RX") 7601a0a46216 ("net/mlx5e: Add a miss level for ipsec crypto offload") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-17mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable().Kuniyuki Iwashima1-4/+7
mptcp_active_enable() is called from subflow_finish_connect(), which is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always under RCU. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dst_dev_rcu(). Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916214758.650211-8-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-17mptcp: Call dst_release() in mptcp_active_enable().Kuniyuki Iwashima1-0/+2
mptcp_active_enable() calls sk_dst_get(), which returns dst with its refcount bumped, but forgot dst_release(). Let's add missing dst_release(). Cc: stable@vger.kernel.org Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916214758.650211-7-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-15mptcp: pm: netlink: fix if-idx typeMatthieu Baerts (NGI0)1-1/+1
As pointed out by Donald, when parsing an entry, the wrong type was set for the temp value: this value is signed. There are no real issues here, because the intermediate variable was only wrong for the sign, not for the size, and the final variable had the right sign. But this feels wrong, and is confusing, so fixing this small typo introduced by commit ef0da3b8a2f1 ("mptcp: move address attribute into mptcp_addr_info"). Reported-by: Donald Hunter <donald.hunter@gmail.com> Closes: https://lore.kernel.org/m2plc0ui9z.fsf@gmail.com Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250912-net-next-mptcp-minor-fixes-6-18-v1-3-99d179b483ad@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-15mptcp: tfo: record 'deny join id0' infoMatthieu Baerts (NGI0)1-3/+3
When TFO is used, the check to see if the 'C' flag (deny join id0) was set was bypassed. This flag can be set when TFO is used, so the check should also be done when TFO is used. Note that the set_fully_established label is also used when a 4th ACK is received. In this case, deny_join_id0 will not be set. Fixes: dfc8d0603033 ("mptcp: implement delayed seq generation for passive fastopen") Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-4-40171884ade8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-15mptcp: pm: nl: announce deny-join-id0 flagMatthieu Baerts (NGI0)1-0/+7
During the connection establishment, a peer can tell the other one that it cannot establish new subflows to the initial IP address and port by setting the 'C' flag [1]. Doing so makes sense when the sender is behind a strict NAT, operating behind a legacy Layer 4 load balancer, or using anycast IP address for example. When this 'C' flag is set, the path-managers must then not try to establish new subflows to the other peer's initial IP address and port. The in-kernel PM has access to this info, but the userspace PM didn't. The RFC8684 [1] is strict about that: (...) therefore the receiver MUST NOT try to open any additional subflows toward this address and port. So it is important to tell the userspace about that as it is responsible for the respect of this flag. When a new connection is created and established, the Netlink events now contain the existing but not currently used 'flags' attribute. When MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 is set, it means no other subflows to the initial IP address and port -- info that are also part of the event -- can be established. Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [1] Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment") Reported-by: Marek Majkowski <marek@cloudflare.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/532 Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-2-40171884ade8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-15mptcp: set remote_deny_join_id0 on SYN recvMatthieu Baerts (NGI0)1-0/+4
When a SYN containing the 'C' flag (deny join id0) was received, this piece of information was not propagated to the path-manager. Even if this flag is mainly set on the server side, a client can also tell the server it cannot try to establish new subflows to the client's initial IP address and port. The server's PM should then record such info when received, and before sending events about the new connection. Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received") Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-1-40171884ade8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-15mptcp: propagate shutdown to subflows when possibleMatthieu Baerts (NGI0)1-0/+16
When the MPTCP DATA FIN have been ACKed, there is no more MPTCP related metadata to exchange, and all subflows can be safely shutdown. Before this patch, the subflows were actually terminated at 'close()' time. That's certainly fine most of the time, but not when the userspace 'shutdown()' a connection, without close()ing it. When doing so, the subflows were staying in LAST_ACK state on one side -- and consequently in FIN_WAIT2 on the other side -- until the 'close()' of the MPTCP socket. Now, when the DATA FIN have been ACKed, all subflows are shutdown. A consequence of this is that the TCP 'FIN' flag can be set earlier now, but the end result is the same. This affects the packetdrill tests looking at the end of the MPTCP connections, but for a good reason. Note that tcp_shutdown() will check the subflow state, so no need to do that again before calling it. Fixes: 3721b9b64676 ("mptcp: Track received DATA_FIN sequence number and add related helpers") Cc: stable@vger.kernel.org Fixes: 16a9a9da1723 ("mptcp: Add helper to process acks of DATA_FIN") Reviewed-by: Mat Martineau <martineau@kernel.org> Reviewed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250912-net-mptcp-fix-sft-connect-v1-1-d40e77cbbf02@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-6/+5
Cross-merge networking fixes after downstream PR (net-6.17-rc6). Conflicts: net/netfilter/nft_set_pipapo.c net/netfilter/nft_set_pipapo_avx2.c c4eaca2e1052 ("netfilter: nft_set_pipapo: don't check genbit from packetpath lookups") 84c1da7b38d9 ("netfilter: nft_set_pipapo: use avx2 algorithm for insertions too") Only trivial adjacent changes (in a doc and a Makefile). Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-09mptcp: make ADD_ADDR retransmission timeout adaptiveGeliang Tang1-4/+24
Currently the ADD_ADDR option is retransmitted with a fixed timeout. This patch makes the retransmission timeout adaptive by using the maximum RTO among all the subflows, while still capping it at the configured maximum value (add_addr_timeout_max). This improves responsiveness when establishing new subflows. Specifically: 1. Adds mptcp_adjust_add_addr_timeout() helper to compute the adaptive timeout. 2. Uses maximum subflow RTO (icsk_rto) when available. 3. Applies exponential backoff based on retransmission count. 4. Maintains fallback to configured max timeout when no RTO data exists. This slightly changes the behaviour of the MPTCP "add_addr_timeout" sysctl knob to be used as a maximum instead of a fixed value. But this is seen as an improvement: the ADD_ADDR might be sent quicker than before to improve the overall MPTCP connection. Also, the default value is set to 2 min, which was already way too long, and caused the ADD_ADDR not to be retransmitted for connections shorter than 2 minutes. Suggested-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/576 Reviewed-by: Christoph Paasch <cpaasch@openai.com> 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://patch.msgid.link/20250907-net-next-mptcp-add_addr-retrans-adapt-v1-1-824cc805772b@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-09mptcp: sockopt: make sync_socket_options propagate SOCK_KEEPOPENKrister Johansen1-6/+5
Users reported a scenario where MPTCP connections that were configured with SO_KEEPALIVE prior to connect would fail to enable their keepalives if MTPCP fell back to TCP mode. After investigating, this affects keepalives for any connection where sync_socket_options is called on a socket that is in the closed or listening state. Joins are handled properly. For connects, sync_socket_options is called when the socket is still in the closed state. The tcp_set_keepalive() function does not act on sockets that are closed or listening, hence keepalive is not immediately enabled. Since the SO_KEEPOPEN flag is absent, it is not enabled later in the connect sequence via tcp_finish_connect. Setting the keepalive via sockopt after connect does work, but would not address any subsequently created flows. Fortunately, the fix here is straight-forward: set SOCK_KEEPOPEN on the subflow when calling sync_socket_options. The fix was valdidated both by using tcpdump to observe keepalive packets not being sent before the fix, and being sent after the fix. It was also possible to observe via ss that the keepalive timer was not enabled on these sockets before the fix, but was enabled afterwards. Fixes: 1b3e7ede1365 ("mptcp: setsockopt: handle SO_KEEPALIVE and SO_PRIORITY") Cc: stable@vger.kernel.org Signed-off-by: Krister Johansen <kjlx@templeofstupid.com> Reviewed-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/aL8dYfPZrwedCIh9@templeofstupid.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-08mptcp: snmp: do not use SNMP_MIB_SENTINEL anymoreEric Dumazet1-6/+6
Use ARRAY_SIZE(), so that we know the limit at compile time. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Mat Martineau <martineau@kernel.org> Cc: Geliang Tang <geliang@kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250905165813.1470708-6-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+0
Cross-merge networking fixes after downstream PR (net-6.17-rc5). No conflicts. Adjacent changes: include/net/sock.h c51613fa276f ("net: add sk->sk_drop_counters") 5d6b58c932ec ("net: lockless sock_i_ino()") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-03net: lockless sock_i_ino()Eric Dumazet1-1/+0
Followup of commit c51da3f7a161 ("net: remove sock_i_uid()") A recent syzbot report was the trigger for this change. Over the years, we had many problems caused by the read_lock[_bh](&sk->sk_callback_lock) in sock_i_uid(). We could fix smc_diag_dump_proto() or make a more radical move: Instead of waiting for new syzbot reports, cache the socket inode number in sk->sk_ino, so that we no longer need to acquire sk->sk_callback_lock in sock_i_ino(). This makes socket dumps faster (one less cache line miss, and two atomic ops avoided). Prior art: commit 25a9c8a4431c ("netlink: Add __sock_i_ino() for __netlink_diag_dump().") commit 4f9bf2a2f5aa ("tcp: Don't acquire inet_listen_hashbucket::lock with disabled BH.") commit efc3dbc37412 ("rds: Make rds_sock_lock BH rather than IRQ safe.") Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.") Reported-by: syzbot+50603c05bbdf4dfdaffa@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/68b73804.050a0220.3db4df.01d8.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20250902183603.740428-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-03mptcp: record subflows in RPS tableChristoph Paasch1-0/+21
Accelerated Receive Flow Steering (aRFS) relies on sockets recording their RX flow hash into the rps_sock_flow_table so that incoming packets are steered to the CPU where the application runs. With MPTCP, the application interacts with the parent MPTCP socket while data is carried over per-subflow TCP sockets. Without recording these subflows, aRFS cannot steer interrupts and RX processing for the flows to the desired CPU. Record all subflows in the RPS table by calling sock_rps_record_flow() for each subflow at the start of mptcp_sendmsg(), mptcp_recvmsg() and mptcp_stream_accept(), by using the new helper mptcp_rps_record_subflows(). It does not by itself improve throughput, but ensures that IRQ and RX processing are directed to the right CPU, which is a prerequisite for effective aRFS. Signed-off-by: Christoph Paasch <cpaasch@openai.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250902-net-next-mptcp-misc-feat-6-18-v2-4-fa02bb3188b1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-03mptcp: use HMAC-SHA256 library instead of open-coded HMACEric Biggers1-33/+2
Now that there are easy-to-use HMAC-SHA256 library functions, use these in net/mptcp/crypto.c instead of open-coding the HMAC algorithm. Remove the WARN_ON_ONCE() for messages longer than SHA256_DIGEST_SIZE. The new implementation handles all message lengths correctly. The mptcp-crypto KUnit test still passes after this change. Signed-off-by: Eric Biggers <ebiggers@kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250902-net-next-mptcp-misc-feat-6-18-v2-1-fa02bb3188b1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-29inet_diag: change inet_diag_bc_sk() first argumentEric Dumazet1-11/+4
We want to have access to the inet_diag_dump_data structure in the following patch. This patch removes duplication in callers. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250828102738.2065992-5-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
generated by cgit v1.2.3 (git 2.39.1) at 2025-12-12 06:15:42 +0000