From: Matthieu Baerts (NGI0) Date: Tue, 5 May 2026 15:00:49 +0000 (+0200) Subject: mptcp: pm: kernel: correctly retransmit ADD_ADDR ID 0 X-Git-Tag: v7.1-rc3~26^2~11^2~10 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b12014d2d36eaed4e4bec5f1ac7e91110eeb100d;p=thirdparty%2Fkernel%2Fstable.git mptcp: pm: kernel: correctly retransmit ADD_ADDR ID 0 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 --- diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c index c9f1e5af3cd3..fc818b63752e 100644 --- a/net/mptcp/pm_kernel.c +++ b/net/mptcp/pm_kernel.c @@ -347,6 +347,8 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) /* check first for announce */ if (msk->pm.add_addr_signaled < endp_signal_max) { + u8 endp_id; + /* due to racing events on both ends we can reach here while * previous add address is still running: if we invoke now * mptcp_pm_announce_addr(), that will fail and the @@ -360,19 +362,20 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) if (!select_signal_address(pernet, msk, &local)) goto subflow; + /* Special case for ID0: set the correct ID */ + endp_id = local.addr.id; + if (endp_id == msk->mpc_endpoint_id) + local.addr.id = 0; + /* If the alloc fails, we are on memory pressure, not worth * continuing, and trying to create subflows. */ if (!mptcp_pm_alloc_anno_list(msk, &local.addr)) return; - __clear_bit(local.addr.id, msk->pm.id_avail_bitmap); + __clear_bit(endp_id, msk->pm.id_avail_bitmap); msk->pm.add_addr_signaled++; - /* Special case for ID0: set the correct ID */ - if (local.addr.id == msk->mpc_endpoint_id) - local.addr.id = 0; - mptcp_pm_announce_addr(msk, &local.addr, false); mptcp_pm_addr_send_ack(msk);