kernel/linux.git/net/mptcp/pm_kernel.c, branch v7.2-rc1

mptcp: pm: uniform announced addresses helpers

2026-06-11T22:33:38+00:00

Similar to the previous commit, only using the 'add' or 'anno' prefixes is confusing -- generally associated to the action of adding something, or the Latin name for "year" -- and lack of uniformity. This has been causing issues in the past, e.g. del_add_timer seemed to suggest the goal is to delete a previously added timer. Instead, use the mptcp_pm_announced_ prefix. While at it, slightly improves some helpers: - mptcp_lookup_anno_list_by_saddr: no need to specify what is used to do the lookup: mptcp_pm_announced_lookup. - mptcp_pm_sport_in_anno_list: it doesn't just compare the port, but the whole address linked to the sublow: mptcp_pm_announced_has_ssk. - mptcp_pm_alloc_anno_list: it allocates one item of the list, not a whole list: mptcp_pm_announced_alloc. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-11-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: use for_each_subflow helper

2026-06-11T22:33:38+00:00

Similar to most places in the MPTCP code. So instead of passing the subflow list and use list_for_each_entry(subflow, list, node), pass the msk and use mptcp_for_each_subflow(msk, subflow). That's clearer and more uniform with the rest. While at it, add 'pm_' prefix for the exported one to easily identify the origin. Plus replace 'lookup' by 'has', because a bool is returned. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-9-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: in-kernel: increase endpoints limit

2026-05-12T01:01:37+00:00

The endpoints are managed in a list which was limited to 8 entries. This limit can be too small in some cases: by having the same limit as the number of subflows, it might not allow creating all expected subflows when having a mix of v4 and v6 addresses that can all use MPTCP on v4/v6 only networks. While increasing the limit above the new subflows one, why not using the technical limit: 255. Indeed, the endpoint will each have an ID that will be used on the wire, limited to u8, and the ID 0 is reserved to the initial subflow. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260508-net-next-mptcp-pm-inc-limits-v1-4-c84e3fdf9b6a@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: kernel: allow flushing more than 8 endpoints

2026-05-12T01:01:37+00:00

The mptcp_rm_list structure contains an array of IDs of 8 entries: to be able to send a RM_ADDR with 8 IDs. This limitation was OK so far because there could maximum 8 endpoints. But this is going to change in the next commit. To cope with that, if one of the arrays is full, the iteration stops, the lists are processed, then the iteration continues where it previously stopped. Note that if there are many endpoints to remove, and multiple RM_ADDR to send, it might be more likely that some of these RM_ADDRs are dropped or lost. This is a known limitation: RM_ADDR are not retransmitted in MPTCPv1. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260508-net-next-mptcp-pm-inc-limits-v1-3-c84e3fdf9b6a@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: in-kernel: increase all limits to 64

2026-05-12T01:01:36+00:00

This means switching the maximum from 8 to 64 for the number of subflows and accepted ADD_ADDR. The previous limit of 8 subflows makes sense in most cases. Using more subflows will very likely *not* improve the situation, and could even decrease the performances. But there are no technical limitations nor performance impact to raise this limit, so let's do it: this will allow people with very specific use-cases, and researchers to easily create more subflows, and measure the performance impact by themselves. The theoretical limit is 255 -- the ID is written in a u8 on the wire -- but 64 is more than enough. With so many subflows, it will be costly to iterate over all of them when operations are done in bottom half. Note that the in-kernel PM will continue to create subflows in reply to ADD_ADDR with a single batch of maximum 8 subflows. Same when adding new "subflow" endpoints with the fullmesh flag. Increasing those batch limits would have a memory impact, and it looks fine not to cover these cases with larger batches for the moment. If more is needed later, the position of the last subflow from the list could be remembered, and the list iteration could continue later. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/434 Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260508-net-next-mptcp-pm-inc-limits-v1-2-c84e3fdf9b6a@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: in-kernel: explicitly limit batches to array size

2026-05-12T01:01:36+00:00

The in-kernel PM can create subflows in reply to ADD_ADDR by batch of maximum 8 subflows for the moment. Same when adding new "subflow" endpoints with the fullmesh flag. This limit is linked to the arrays used during these steps. There was no explicit limit to the arrays size (8), because the limit of extra subflows is the same (8). It seems safer to use an explicit limit, but also these two sizes are going to be different in the next commit. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260508-net-next-mptcp-pm-inc-limits-v1-1-c84e3fdf9b6a@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: kernel: correctly retransmit ADD_ADDR ID 0

2026-05-07T01:16:44+00:00

When adding the ADD_ADDR to the list, the address including the IP, port and ID are copied. On the other hand, when the endpoint corresponds to the one from the initial subflow, the ID is set to 0, as specified by the MPTCP protocol. The issue is that the ID was reset after having copied the ID in the ADD_ADDR entry. So the retransmission was done, but using a different ID than the initial one. Fixes: 8b8ed1b429f8 ("mptcp: pm: reuse ID 0 after delete and re-add") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260505-net-mptcp-pm-fixes-7-1-rc3-v1-1-fca8091060a4@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: kernel: reset fullmesh counter after flush

2026-04-29T01:36:27+00:00

This variable counts how many MPTCP endpoints have a 'fullmesh' flag set. After having flushed all MPTCP endpoints, it is then needed to reset this counter. Without this reset, this counter exposed to the userspace is wrong, but also non-fullmesh endpoints added after the flush will not be taken into account to create subflows in reaction to ADD_ADDRs. Fixes: f88191c7f361 ("mptcp: pm: in-kernel: record fullmesh endp nb") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://sashiko.dev/#/patchset/20260422-mptcp-inc-limits-v6-0-903181771530%40kernel.org?part=15 Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260427-net-mptcp-misc-fixes-7-1-rc2-v1-4-7432b7f279fa@kernel.org Signed-off-by: Jakub Kicinski

Revert "mptcp: add needs_id for netlink appending addr"

2026-04-09T02:31:16+00:00

This commit was originally adding the ability to add MPTCP endpoints with ID 0 by accident. The in-kernel PM, handling MPTCP endpoints at the net namespace level, is not supposed to handle endpoints with such ID, because this ID 0 is reserved to the initial subflow, as mentioned in the MPTCPv1 protocol [1], a per-connection setting. Note that 'ip mptcp endpoint add id 0' stops early with an error, but other tools might still request the in-kernel PM to create MPTCP endpoints with this restricted ID 0. In other words, it was wrong to call the mptcp_pm_has_addr_attr_id helper to check whether the address ID attribute is set: if it was set to 0, a new MPTCP endpoint would be created with ID 0, which is not expected, and might cause various issues later. Fixes: 584f38942626 ("mptcp: add needs_id for netlink appending addr") Cc: stable@vger.kernel.org Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.2-9 [1] Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260407-net-mptcp-revert-pm-needs-id-v2-1-7a25cbc324f8@kernel.org Signed-off-by: Jakub Kicinski

MPTCP: fix lock class name family in pm_nl_create_listen_socket

2026-03-19T16:37:48+00:00

In mptcp_pm_nl_create_listen_socket(), use entry->addr.family instead of sk->sk_family for lock class setup. The 'sk' parameter is a netlink socket, not the MPTCP subflow socket being created. Fixes: cee4034a3db1 ("mptcp: fix lockdep false positive in mptcp_pm_nl_create_listen_socket()") Signed-off-by: Li Xiasong Reviewed-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260319112159.3118874-1-lixiasong1@huawei.com Signed-off-by: Jakub Kicinski