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

mptcp: options: rst: drop unused skb parameter

2026-06-11T22:33:39+00:00

It was passed since its introduction in commit dc87efdb1a5c ("mptcp: add mptcp reset option support"), but never used. Simply removes it. Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-15-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: avoid using del_timer directly

2026-06-11T22:33:39+00:00

mptcp_pm_announced_del_timer() removes the matched ADD_ADDR entry (if found) from the ADD_ADDR list only if check_id is false. That's dangerous, and not clear, because it means the caller should be free the entry only in some cases, and it easy to miss that. Instead, make it static, and call it from mptcp_pm_add_addr_echoed, which is the only other case where mptcp_pm_add_addr_del_timer should be called with check_id set to true. Bonus with that: a second call to mptcp_pm_add_addr_lookup_by_addr() can be avoided. Note that instead of adding the signature above to avoid a compilation issue because this helper is called before the definition of the function, the whole helper is moved above where it is first called. Its content is untouched, except the addition of the 'static' keyboard. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-14-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: make mptcp_pm_add_addr_send_ack static

2026-06-11T22:33:39+00:00

Only used in pm.c. Note that the signature is added above: it is easier than moving the code around, because this helper depends on mptcp_pm_schedule_work which is declared below. While at it, explicitly mark it as to be called while pm->lock is held. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-13-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

mptcp: pm: remove add_ prefix from timer

2026-06-11T22:33:39+00:00

Similar to the two previous commits, using the 'add' prefix is confusing, also confirmed by [1]. Now that the structure has been renamed to include 'add_addr' in its name, easier to know the timer is linked to the ADD_ADDR, no need to add the confusing prefix, or an unneeded longer one. While at it, also update the ADD_ADDR timer helper to clearly specify it is linked to ADD_ADDR, and it is not there to add a new timer. Link: https://lore.kernel.org/20251117100745.1913963-1-edumazet@google.com [1] Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-12-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

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: rename add_entry structure to add_addr

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

Using only the 'add' prefix is confusing: does it refer to a generic added entry or address, or specifically to ADD_ADDRs. Using add_addr removes this confusion. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-10-758e7ca73f4d@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: drop TCP TS with ADD_ADDRv6 + port

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

With TCP-timestamps (padded) taking 12 bytes and ADD_ADDR IPv6 + port taking 30 bytes, the 40-byte limit for the TCP options is reached. In this case, it is then not possible to send the signal. To be able to send this ADD_ADDR, the TCP timestamps option can now be dropped. This is done, when needed by setting the *drop_ts parameter from mptcp_established_options. This feature is controlled by a new net.mptcp.add_addr_v6_port_drop_ts sysctl knob, enabled by default. It is important to keep in mind that dropping the TCP timestamps option for one packet of the connection could eventually disrupt some middleboxes: even if it should be unlikely, they could drop the packet or even block the connection. That's why this new feature can be controlled by a sysctl knob. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/448 Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-6-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

tcp: allow mptcp to drop TS for some packets

2026-06-11T22:33:37+00:00

With TCP-timestamps (padded) taking 12 bytes and ADD_ADDR IPv6 + port taking 30 bytes, the 40-byte limit for the TCP options is reached. In this case, it is then not possible to send the address signal. The idea is to let MPTCP dropping the TCP-timestamps option for some specific packets, to be able to send some specific pure ACK carrying >28 bytes of MPTCP options, like with this specific ADD_ADDR. A new parameter is passed from tcp_established_options to the MPTCP side to indicate if the TCP TS option is used, and if it should be dropped. The next commit implements the part on MPTCP side, but split into two patches to help TCP maintainers to identify the modifications on TCP side. This feature will be controlled by a new add_addr_v6_port_drop_ts MPTCP sysctl knob. It is important to keep in mind that dropping the TCP timestamps option for one packet of the connection could eventually disrupt some middleboxes: even if it should be unlikely, they could drop the packet or even block the connection. That's why this new feature will be controlled by a sysctl knob. Note that it would be technically possible to squeeze both options into the header if the ADD_ADDR is first written, and then the TCP timestamps without the NOPs preceding it. But this means more modifications on TCP side, plus some middleboxes could still be disrupted by that. In this implementation, an unused bit is used in mptcp_out_options structure to avoid passing an address to a local variable. Reading and setting it needs CONFIG_MPTCP, so the whole block now has this #if condition: mptcp_established_options() is then no longer used without CONFIG_MPTCP. About alternatives, instead of passing a new boolean (has_ts), another option would be to pass the whole option structure (opts), but 'struct tcp_out_options' is currently defined in tcp_output.c, and it would need to be exported. Plus that means the removal of the TCP TS option would be done on the MPTCP side, and not here on the TCP side. It feels clearer to remove other TCP options from the TCP side, than hiding that from the MPTCP side. Yet an other alternative would be to pass the size already taken by the other TCP options, and have a way to drop them all when needed. But this feels better to target only the timestamps option where dropping it should be safe, even if it is currently the only option that would be set before MPTCP, when MPTCP is used. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-5-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski

mptcp: introduce add_addr_v6_port_drop_ts sysctl knob

2026-06-11T22:33:37+00:00

This sysctl is going to be used in the next commits to drop TCP timestamps option, to be able to send an ADD_ADDR with a v6 IP address and a port number. It is enabled by default. This knob is explicitly disabled in the MPTCP Join selftest, with the "signal addr list progresses after tx drop" subtest, to continue verifying the previous behaviour where the ADD_ADDR is not sent due to a lack of space. While at it, move syn_retrans_before_tcp_fallback down from struct mptcp_pernet, to avoid creating another 3 bytes hole. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260605-net-next-mptcp-add-addr6-port-ts-v2-4-758e7ca73f4d@kernel.org Signed-off-by: Jakub Kicinski