kernel/linux.git/include/net/mptcp.h, branch v7.1

mptcp: fix uninit-value in mptcp_established_options

2026-06-04T02:04:27+00:00

syzbot reported the following uninit splat: BUG: KMSAN: uninit-value in mptcp_write_data_fin net/mptcp/options.c:542 [inline] BUG: KMSAN: uninit-value in mptcp_established_options_dss net/mptcp/options.c:590 [inline] BUG: KMSAN: uninit-value in mptcp_established_options+0x112f/0x3530 net/mptcp/options.c:874 mptcp_write_data_fin net/mptcp/options.c:542 [inline] mptcp_established_options_dss net/mptcp/options.c:590 [inline] mptcp_established_options+0x112f/0x3530 net/mptcp/options.c:874 tcp_established_options+0x312/0xcc0 net/ipv4/tcp_output.c:1192 __tcp_transmit_skb+0x5dc/0x5fe0 net/ipv4/tcp_output.c:1575 __tcp_send_ack+0x967/0xad0 net/ipv4/tcp_output.c:4499 tcp_send_ack+0x3d/0x60 net/ipv4/tcp_output.c:4505 mptcp_subflow_shutdown+0x164/0x690 net/mptcp/protocol.c:3137 mptcp_check_send_data_fin+0x31b/0x3d0 net/mptcp/protocol.c:3218 __mptcp_wr_shutdown net/mptcp/protocol.c:3234 [inline] __mptcp_close+0x860/0x1360 net/mptcp/protocol.c:3313 mptcp_close+0x42/0x260 net/mptcp/protocol.c:3367 inet_release+0x1ee/0x2a0 net/ipv4/af_inet.c:442 __sock_release net/socket.c:722 [inline] sock_close+0xd6/0x2f0 net/socket.c:1514 __fput+0x60e/0x1010 fs/file_table.c:510 ____fput+0x25/0x30 fs/file_table.c:538 task_work_run+0x208/0x2b0 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0x306/0x1b60 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] __do_fast_syscall_32+0x2c7/0x460 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x37/0x80 arch/x86/entry/syscall_32.c:332 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:370 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Local variable opts created at: __tcp_transmit_skb+0x4d/0x5fe0 net/ipv4/tcp_output.c:1536 __tcp_send_ack+0x967/0xad0 net/ipv4/tcp_output.c:4499 The output path currently omits initializing the mptcp extension `use_map` flag in a few corner cases. Address the issue always zeroing all the extensions flags before eventually initializing the individual bits. To that extent, introduce and use a struct_group to avoid multiple bitwise operations. Fixes: cfcceb7a39fc ("tcp: shrink per-packet memset in __tcp_transmit_skb()") Cc: stable@vger.kernel.org Reported-by: syzbot+ff020673c5e3d94d9478@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ff020673c5e3d94d9478 Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-10-856831229976@kernel.org Signed-off-by: Jakub Kicinski

mptcp: sched: remove mptcp_sched_data

2025-04-15T15:21:46+00:00

This is a follow-up of commit b68b106b0f15 ("mptcp: sched: reduce size for unused data"), now removing the mptcp_sched_data structure. Now is a good time to do that, because the previously mentioned WIP work has been updated, no longer depending on this structure. Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250413-net-next-mptcp-sched-mib-sft-misc-v2-1-0f83a4350150@kernel.org Signed-off-by: Jakub Kicinski

mptcp: sysctl: add available_path_managers

2025-03-20T09:14:49+00:00

Similarly to net.mptcp.available_schedulers, this patch adds a new one net.mptcp.available_path_managers to list the available path managers. Signed-off-by: Geliang Tang Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-11-f4e4a88efc50@kernel.org Signed-off-by: Paolo Abeni

mptcp: pm: define struct mptcp_pm_ops

2025-03-20T09:14:48+00:00

In order to allow users to develop their own BPF-based path manager, this patch defines a struct ops "mptcp_pm_ops" for an MPTCP path manager, which contains a set of interfaces. Currently only init() and release() interfaces are included, subsequent patches will add others step by step. Add a set of functions to register, unregister, find and validate a given path manager struct ops. "list" is used to add this path manager to mptcp_pm_list list when it is registered. "name" is used to identify this path manager. mptcp_pm_find() uses "name" to find a path manager on the list. mptcp_pm_unregister is not used in this set, but will be invoked in .unreg of struct bpf_struct_ops. mptcp_pm_validate() will be invoked in .validate of struct bpf_struct_ops. That's why they are exported. Signed-off-by: Geliang Tang Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-6-f4e4a88efc50@kernel.org Signed-off-by: Paolo Abeni

mptcp: sched: split get_subflow interface into two

2025-02-25T02:23:44+00:00

get_retrans() interface of the burst packet scheduler invokes a sleeping function mptcp_pm_subflow_chk_stale(), which calls __lock_sock_fast(). So get_retrans() interface should be set with BPF_F_SLEEPABLE flag in BPF. But get_send() interface of this scheduler can't be set with BPF_F_SLEEPABLE flag since it's invoked in ack_update_msk() under mptcp data lock. So this patch has to split get_subflow() interface of packet scheduer into two interfaces: get_send() and get_retrans(). Then we can set get_retrans() interface alone with BPF_F_SLEEPABLE flag. Signed-off-by: Geliang Tang Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250221-net-next-mptcp-pm-misc-cleanup-3-v1-8-2b70ab1cee79@kernel.org Signed-off-by: Jakub Kicinski

mptcp: fallback to TCP after SYN+MPC drops

2024-09-11T22:57:50+00:00

Some middleboxes might be nasty with MPTCP, and decide to drop packets with MPTCP options, instead of just dropping the MPTCP options (or letting them pass...). In this case, it sounds better to fallback to "plain" TCP after 2 retransmissions, and try again. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/477 Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20240909-net-next-mptcp-fallback-x-mpc-v1-2-da7ebb4cd2a3@kernel.org Signed-off-by: Jakub Kicinski

mptcp: add net.mptcp.available_schedulers

2024-05-14T01:29:23+00:00

The sysctl lists the available schedulers that can be set using net.mptcp.scheduler similarly to net.ipv4.tcp_available_congestion_control. Signed-off-by: Gregory Detal Reviewed-by: Mat Martineau Tested-by: Geliang Tang Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Mat Martineau Link: https://lore.kernel.org/r/20240514011335.176158-5-martineau@kernel.org Signed-off-by: Jakub Kicinski

mptcp: add struct mptcp_sched_ops

2023-08-23T00:31:18+00:00

This patch defines struct mptcp_sched_ops, which has three struct members, name, owner and list, and four function pointers: init(), release() and get_subflow(). The scheduler function get_subflow() have a struct mptcp_sched_data parameter, which contains a reinject flag for retrans or not, a subflows number and a mptcp_subflow_context array. Add the scheduler registering, unregistering and finding functions to add, delete and find a packet scheduler on the global list mptcp_sched_list. Acked-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Geliang Tang Signed-off-by: Mat Martineau Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-3-0c860fb256a8@kernel.org Signed-off-by: Jakub Kicinski

mptcp: remove MPTCP 'ifdef' in TCP SYN cookies

2022-12-12T21:11:24+00:00

To ease the maintenance, it is often recommended to avoid having #ifdef preprocessor conditions. Here the section related to CONFIG_MPTCP was quite short but the next commit needs to add more code around. It is then cleaner to move specific MPTCP code to functions located in net/mptcp directory. Now that mptcp_subflow_request_sock_ops structure can be static, it can also be marked as "read only after init". Suggested-by: Paolo Abeni Reviewed-by: Mat Martineau Cc: stable@vger.kernel.org Signed-off-by: Matthieu Baerts Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski

mptcp, btf: Add struct mptcp_sock definition when CONFIG_MPTCP is disabled

2022-08-08T13:30:45+00:00

The btf_sock_ids array needs struct mptcp_sock BTF ID for the bpf_skc_to_mptcp_sock helper. When CONFIG_MPTCP is disabled, the 'struct mptcp_sock' is not defined and resolve_btfids will complain with: [...] BTFIDS vmlinux WARN: resolve_btfids: unresolved symbol mptcp_sock [...] Add an empty definition for struct mptcp_sock when CONFIG_MPTCP is disabled. Fixes: 3bc253c2e652 ("bpf: Add bpf_skc_to_mptcp_sock_proto") Signed-off-by: Jiri Olsa Signed-off-by: Daniel Borkmann Reviewed-by: Mat Martineau Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20220802163324.1873044-1-jolsa@kernel.org