kernel.git/net/mptcp, branch linux-6.8.y

mptcp: fix full TCP keep-alive support

2024-05-30T07:49:28Z

[ Upstream commit bd11dc4fb969ec148e50cd87f88a78246dbc4d0b ] SO_KEEPALIVE support has been added a while ago, as part of a series "adding SOL_SOCKET" support. To have a full control of this keep-alive feature, it is important to also support TCP_KEEP* socket options at the SOL_TCP level. Supporting them on the setsockopt() part is easy, it is just a matter of remembering each value in the MPTCP sock structure, and calling tcp_sock_set_keep*() helpers on each subflow. If the value is not modified (0), calling these helpers will not do anything. For the getsockopt() part, the corresponding value from the MPTCP sock structure or the default one is simply returned. All of this is very similar to other TCP_* socket options supported by MPTCP. It looks important for kernels supporting SO_KEEPALIVE, to also support TCP_KEEP* options as well: some apps seem to (wrongly) consider that if the former is supported, the latter ones will be supported as well. But also, not having this simple and isolated change is preventing MPTCP support in some apps, and libraries like GoLang [1]. This is why this patch is seen as a fix. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/383 Fixes: 1b3e7ede1365 ("mptcp: setsockopt: handle SO_KEEPALIVE and SO_PRIORITY") Link: https://github.com/golang/go/issues/56539 [1] Acked-by: Paolo Abeni Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Mat Martineau Link: https://lore.kernel.org/r/20240514011335.176158-3-martineau@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mptcp: cleanup SOL_TCP handling

2024-05-30T07:49:28Z

[ Upstream commit 7f71a337b5152ea0e7bef408d1af53778a919316 ] Most TCP-level socket options get an integer from user space, and set the corresponding field under the msk-level socket lock. Reduce the code duplication moving such operations in the common code. Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: David S. Miller Stable-dep-of: bd11dc4fb969 ("mptcp: fix full TCP keep-alive support") Signed-off-by: Sasha Levin

mptcp: implement TCP_NOTSENT_LOWAT support

2024-05-30T07:49:28Z

[ Upstream commit 29b5e5ef87397963ca38d3eec0d296ad1c979bbc ] Add support for such socket option storing the user-space provided value in a new msk field, and using such data to implement the _mptcp_stream_memory_free() helper, similar to the TCP one. To avoid adding more indirect calls in the fast path, open-code a variant of sk_stream_memory_free() in mptcp_sendmsg() and add direct calls to the mptcp stream memory free helper where possible. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/464 Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: David S. Miller Stable-dep-of: bd11dc4fb969 ("mptcp: fix full TCP keep-alive support") Signed-off-by: Sasha Levin

mptcp: avoid some duplicate code in socket option handling

2024-05-30T07:49:28Z

[ Upstream commit a74762675f700a5473ebe54a671a0788a5b23cc9 ] The mptcp_get_int_option() helper is needless open-coded in a couple of places, replace the duplicate code with the helper call. Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: David S. Miller Stable-dep-of: bd11dc4fb969 ("mptcp: fix full TCP keep-alive support") Signed-off-by: Sasha Levin

mptcp: cleanup writer wake-up

2024-05-30T07:49:28Z

[ Upstream commit 037db6ea57da7a134a8183dead92d64ef92babee ] After commit 5cf92bbadc58 ("mptcp: re-enable sndbuf autotune"), the MPTCP_NOSPACE bit is redundant: it is always set and cleared together with SOCK_NOSPACE. Let's drop the first and always relay on the latter, dropping a bunch of useless code. Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: David S. Miller Stable-dep-of: bd11dc4fb969 ("mptcp: fix full TCP keep-alive support") Signed-off-by: Sasha Levin

mptcp: SO_KEEPALIVE: fix getsockopt support

2024-05-30T07:49:28Z

[ Upstream commit a65198136eaa15b74ee0abf73f12ef83d469a334 ] SO_KEEPALIVE support has to be set on each subflow: on each TCP socket, where sk_prot->keepalive is defined. Technically, nothing has to be done on the MPTCP socket. That's why mptcp_sol_socket_sync_intval() was called instead of mptcp_sol_socket_intval(). Except that when nothing is done on the MPTCP socket, the getsockopt(SO_KEEPALIVE), handled in net/core/sock.c:sk_getsockopt(), will not know if SO_KEEPALIVE has been set on the different subflows or not. The fix is simple: simply call mptcp_sol_socket_intval() which will end up calling net/core/sock.c:sk_setsockopt() where the SOCK_KEEPOPEN flag will be set, the one used in sk_getsockopt(). So now, getsockopt(SO_KEEPALIVE) on an MPTCP socket will return the same value as the one previously set with setsockopt(SO_KEEPALIVE). Fixes: 1b3e7ede1365 ("mptcp: setsockopt: handle SO_KEEPALIVE and SO_PRIORITY") Acked-by: Paolo Abeni Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Mat Martineau Link: https://lore.kernel.org/r/20240514011335.176158-2-martineau@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mptcp: only allow set existing scheduler for net.mptcp.scheduler

2024-05-17T10:15:02Z

commit 6963c508fd7ab66ae0b7ae3db9a62ca6267f1ae8 upstream. The current behavior is to accept any strings as inputs, this results in an inconsistent result where an unexisting scheduler can be set: # sysctl -w net.mptcp.scheduler=notdefault net.mptcp.scheduler = notdefault This patch changes this behavior by checking for existing scheduler before accepting the input. Fixes: e3b2870b6d22 ("mptcp: add a new sysctl scheduler") Cc: stable@vger.kernel.org Signed-off-by: Gregory Detal Reviewed-by: Matthieu Baerts (NGI0) Tested-by: Geliang Tang Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://lore.kernel.org/r/20240506-upstream-net-20240506-mptcp-sched-exist-v1-1-2ed1529e521e@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

mptcp: ensure snd_nxt is properly initialized on connect

2024-05-17T10:15:01Z

commit fb7a0d334894206ae35f023a82cad5a290fd7386 upstream. Christoph reported a splat hinting at a corrupted snd_una: WARNING: CPU: 1 PID: 38 at net/mptcp/protocol.c:1005 __mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005 Modules linked in: CPU: 1 PID: 38 Comm: kworker/1:1 Not tainted 6.9.0-rc1-gbbeac67456c9 #59 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 Workqueue: events mptcp_worker RIP: 0010:__mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005 Code: be 06 01 00 00 bf 06 01 00 00 e8 a8 12 e7 fe e9 00 fe ff ff e8 8e 1a e7 fe 0f b7 ab 3e 02 00 00 e9 d3 fd ff ff e8 7d 1a e7 fe <0f> 0b 4c 8b bb e0 05 00 00 e9 74 fc ff ff e8 6a 1a e7 fe 0f 0b e9 RSP: 0018:ffffc9000013fd48 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff8881029bd280 RCX: ffffffff82382fe4 RDX: ffff8881003cbd00 RSI: ffffffff823833c3 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: fefefefefefefeff R12: ffff888138ba8000 R13: 0000000000000106 R14: ffff8881029bd908 R15: ffff888126560000 FS: 0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f604a5dae38 CR3: 0000000101dac002 CR4: 0000000000170ef0 Call Trace: __mptcp_clean_una_wakeup net/mptcp/protocol.c:1055 [inline] mptcp_clean_una_wakeup net/mptcp/protocol.c:1062 [inline] __mptcp_retrans+0x7f/0x7e0 net/mptcp/protocol.c:2615 mptcp_worker+0x434/0x740 net/mptcp/protocol.c:2767 process_one_work+0x1e0/0x560 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x3c7/0x640 kernel/workqueue.c:3416 kthread+0x121/0x170 kernel/kthread.c:388 ret_from_fork+0x44/0x50 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 When fallback to TCP happens early on a client socket, snd_nxt is not yet initialized and any incoming ack will copy such value into snd_una. If the mptcp worker (dumbly) tries mptcp-level re-injection after such ack, that would unconditionally trigger a send buffer cleanup using 'bad' snd_una values. We could easily disable re-injection for fallback sockets, but such dumb behavior already helped catching a few subtle issues and a very low to zero impact in practice. Instead address the issue always initializing snd_nxt (and write_seq, for consistency) at connect time. Fixes: 8fd738049ac3 ("mptcp: fallback in case of simultaneous connect") Cc: stable@vger.kernel.org Reported-by: Christoph Paasch Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/485 Tested-by: Christoph Paasch Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://lore.kernel.org/r/20240429-upstream-net-20240429-mptcp-snd_nxt-init-connect-v1-1-59ceac0a7dcb@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

mptcp: don't account accept() of non-MPC client as fallback to TCP

2024-04-10T14:38:09Z

[ Upstream commit 7a1b3490f47e88ec4cbde65f1a77a0f4bc972282 ] 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: fc518953bc9c ("mptcp: add and use MIB counter infrastructure") Cc: stable@vger.kernel.org Reported-by: Christoph Paasch Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/449 Signed-off-by: Davide Caratti Reviewed-by: Mat Martineau Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://lore.kernel.org/r/20240329-upstream-net-20240329-fallback-mib-v1-1-324a8981da48@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mptcp: prevent BPF accessing lowat from a subflow socket.

2024-04-10T14:38:04Z

commit fcf4692fa39e86a590c14a4af2de704e1d20a3b5 upstream. Alexei reported the following splat: WARNING: CPU: 32 PID: 3276 at net/mptcp/subflow.c:1430 subflow_data_ready+0x147/0x1c0 Modules linked in: dummy bpf_testmod(O) [last unloaded: bpf_test_no_cfi(O)] CPU: 32 PID: 3276 Comm: test_progs Tainted: GO 6.8.0-12873-g2c43c33bfd23 Call Trace: mptcp_set_rcvlowat+0x79/0x1d0 sk_setsockopt+0x6c0/0x1540 __bpf_setsockopt+0x6f/0x90 bpf_sock_ops_setsockopt+0x3c/0x90 bpf_prog_509ce5db2c7f9981_bpf_test_sockopt_int+0xb4/0x11b bpf_prog_dce07e362d941d2b_bpf_test_socket_sockopt+0x12b/0x132 bpf_prog_348c9b5faaf10092_skops_sockopt+0x954/0xe86 __cgroup_bpf_run_filter_sock_ops+0xbc/0x250 tcp_connect+0x879/0x1160 tcp_v6_connect+0x50c/0x870 mptcp_connect+0x129/0x280 __inet_stream_connect+0xce/0x370 inet_stream_connect+0x36/0x50 bpf_trampoline_6442491565+0x49/0xef inet_stream_connect+0x5/0x50 __sys_connect+0x63/0x90 __x64_sys_connect+0x14/0x20 The root cause of the issue is that bpf allows accessing mptcp-level proto_ops from a tcp subflow scope. Fix the issue detecting the problematic call and preventing any action. Reported-by: Alexei Starovoitov Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/482 Fixes: 5684ab1a0eff ("mptcp: give rcvlowat some love") Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Reviewed-by: Matthieu Baerts (NGI0) Link: https://lore.kernel.org/r/d8cb7d8476d66cb0812a6e29cd1e626869d9d53e.1711738080.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman