Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Minor conflicts in net/mptcp/protocol.h and
tools/testing/selftests/net/Makefile.

In both cases code was added on both sides in the same place
so just keep both.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 26 insertions, 8 deletions

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 4d35fa998fcc..092a2d48bfd3 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -517,7 +517,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
 		return ret;
 	}
 
-	if (subflow->use_64bit_ack) {
+	if (READ_ONCE(msk->use_64bit_ack)) {
 		ack_size = TCPOLEN_MPTCP_DSS_ACK64;
 		opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
 		opts->ext_copy.ack64 = 1;
@@ -657,6 +657,12 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 	if (unlikely(mptcp_check_fallback(sk)))
 		return false;
 
+	/* prevent adding of any MPTCP related options on reset packet
+	 * until we support MP_TCPRST/MP_FASTCLOSE
+	 */
+	if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
+		return false;
+
 	if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
 		ret = true;
 	else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
@@ -711,7 +717,7 @@ bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
 	return false;
 }
 
-static bool check_fully_established(struct mptcp_sock *msk, struct sock *sk,
+static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
 				    struct mptcp_subflow_context *subflow,
 				    struct sk_buff *skb,
 				    struct mptcp_options_received *mp_opt)
@@ -728,15 +734,20 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *sk,
 		    TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
 		    subflow->mp_join && mp_opt->mp_join &&
 		    READ_ONCE(msk->pm.server_side))
-			tcp_send_ack(sk);
+			tcp_send_ack(ssk);
 		goto fully_established;
 	}
 
-	/* we should process OoO packets before the first subflow is fully
-	 * established, but not expected for MP_JOIN subflows
+	/* we must process OoO packets before the first subflow is fully
+	 * established. OoO packets are instead a protocol violation
+	 * for MP_JOIN subflows as the peer must not send any data
+	 * before receiving the forth ack - cfr. RFC 8684 section 3.2.
 	 */
-	if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1)
+	if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
+		if (subflow->mp_join)
+			goto reset;
 		return subflow->mp_capable;
+	}
 
 	if (mp_opt->dss && mp_opt->use_ack) {
 		/* subflows are fully established as soon as we get any
@@ -748,9 +759,12 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *sk,
 	}
 
 	/* If the first established packet does not contain MP_CAPABLE + data
-	 * then fallback to TCP
+	 * then fallback to TCP. Fallback scenarios requires a reset for
+	 * MP_JOIN subflows.
 	 */
 	if (!mp_opt->mp_capable) {
+		if (subflow->mp_join)
+			goto reset;
 		subflow->mp_capable = 0;
 		pr_fallback(msk);
 		__mptcp_do_fallback(msk);
@@ -767,12 +781,16 @@ fully_established:
 
 	subflow->pm_notified = 1;
 	if (subflow->mp_join) {
-		clear_3rdack_retransmission(sk);
+		clear_3rdack_retransmission(ssk);
 		mptcp_pm_subflow_established(msk, subflow);
 	} else {
 		mptcp_pm_fully_established(msk);
 	}
 	return true;
+
+reset:
+	mptcp_subflow_reset(ssk);
+	return false;
 }
 
 static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)