From 342a3a0be5572c6faad763e59bf7927e2ddc2073 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Mon, 28 Oct 2024 05:53:55 +0000 Subject: [PATCH] mptcp: use "middlebox interference" RST when no DSS RFC8684 suggests use of "Middlebox interference (code 0x06)" in case of fully established subflow that carries data at TCP level with no DSS sub-option. This is generally the case when mpext is NULL or mpext->use_map is 0: use a dedicated value of 'mapping_status' and use it before closing the socket in subflow_check_data_avail(). Link: https://github.com/multipath-tcp/mptcp_net-next/issues/518 Signed-off-by: Davide Caratti --- net/mptcp/subflow.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 860903e064225..07352b15f1458 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -971,7 +971,8 @@ enum mapping_status { MAPPING_EMPTY, MAPPING_DATA_FIN, MAPPING_DUMMY, - MAPPING_BAD_CSUM + MAPPING_BAD_CSUM, + MAPPING_NODSS }; static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn) @@ -1128,8 +1129,9 @@ static enum mapping_status get_mapping_status(struct sock *ssk, return MAPPING_EMPTY; } + /* If the required DSS has likely been dropped by a middlebox */ if (!subflow->map_valid) - return MAPPING_INVALID; + return MAPPING_NODSS; goto validate_seq; } @@ -1343,7 +1345,7 @@ static bool subflow_check_data_avail(struct sock *ssk) status = get_mapping_status(ssk, msk); trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue)); if (unlikely(status == MAPPING_INVALID || status == MAPPING_DUMMY || - status == MAPPING_BAD_CSUM)) + status == MAPPING_BAD_CSUM || status == MAPPING_NODSS)) goto fallback; if (status != MAPPING_OK) @@ -1396,7 +1398,9 @@ static bool subflow_check_data_avail(struct sock *ssk) * subflow_error_report() will introduce the appropriate barriers */ subflow->reset_transient = 0; - subflow->reset_reason = MPTCP_RST_EMPTCP; + subflow->reset_reason = status == MAPPING_NODSS ? + MPTCP_RST_EMIDDLEBOX : + MPTCP_RST_EMPTCP; reset: WRITE_ONCE(ssk->sk_err, EBADMSG);