Merge branch 'mptcp-misc-fixes-for-v7-1-rc3'

Matthieu Baerts says:

====================
mptcp: misc fixes for v7.1-rc3

Here are various unrelated fixes:

- Patch 1: increment the right MIB counter. A fix for v5.7.

- Patch 2: set the right MPTCP reset reason. A fix for v5.9.

- Patch 3: fix rx timestamp corruption when on MPTCP passive fastopen. A
  fix for v6.2.

- Patch 4: increase sockopt seq after having set TCP_MAXSEG to propagate
  it to newer subflows later. A fix for 6.17.
====================

Link: https://patch.msgid.link/20260501-net-mptcp-misc-fixes-7-1-rc3-v1-0-b70118df778e@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 9 insertions, 3 deletions

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
index 82ec15bcfd7f..082c46c0f50e 100644
--- a/net/mptcp/fastopen.c
+++ b/net/mptcp/fastopen.c
@@ -12,6 +12,7 @@ void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subf
 	struct sock *sk, *ssk;
 	struct sk_buff *skb;
 	struct tcp_sock *tp;
+	bool has_rxtstamp;
 
 	/* on early fallback the subflow context is deleted by
 	 * subflow_syn_recv_sock()
@@ -40,12 +41,13 @@ void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subf
 	 */
 	tp->copied_seq += skb->len;
 	subflow->ssn_offset += skb->len;
+	has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
 
 	/* Only the sequence delta is relevant */
 	MPTCP_SKB_CB(skb)->map_seq = -skb->len;
 	MPTCP_SKB_CB(skb)->end_seq = 0;
 	MPTCP_SKB_CB(skb)->offset = 0;
-	MPTCP_SKB_CB(skb)->has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
+	MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
 	MPTCP_SKB_CB(skb)->cant_coalesce = 1;
 
 	mptcp_data_lock(sk);
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 0efe40be2fde..1cf608e7357b 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -812,6 +812,10 @@ static int mptcp_setsockopt_all_sf(struct mptcp_sock *msk, int level,
 		if (ret)
 			break;
 	}
+
+	if (!ret)
+		sockopt_seq_inc(msk);
+
 	return ret;
 }
 
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index e2cb9d23e4a0..d562e149606f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -581,7 +581,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 			 subflow->backup);
 
 		if (!subflow_thmac_valid(subflow)) {
-			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC);
+			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKMAC);
 			subflow->reset_reason = MPTCP_RST_EMPTCP;
 			goto do_reset;
 		}
@@ -908,7 +908,7 @@ create_child:
 
 			if (!subflow_hmac_valid(subflow_req, &mp_opt)) {
 				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
-				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
+				subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
 				goto dispose_child;
 			}