[MPTCP] [PATCH v1 7/7] Squash-to: "mptcp: Add handling of incoming MP_JOIN requests"

[MPTCP] [PATCH v1 7/7] Squash-to: "mptcp: Add handling of incoming MP_JOIN requests"

[Paolo Abeni]

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ensure fallback is fatal for MP_JOIN, copying with
changes introduced by previous squash-to patches

Signed-off-by: Paolo Abeni <pabeni(a)redhat.com>
---
 net/mptcp/subflow.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 4e846b4e0b81..49d430479124 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -256,6 +256,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 	struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
 	struct mptcp_subflow_request_sock *subflow_req;
 	struct tcp_options_received opt_rx;
+	bool fallback_is_fatal = false;
 	struct sock *child;
 
 	pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
@@ -280,6 +281,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 			subflow_req->mp_capable = 0;
 		}
 	} else if (subflow_req->mp_join) {
+		fallback_is_fatal = true;
 		opt_rx.mptcp.mp_join = 0;
 		mptcp_get_options(skb, &opt_rx);
 		if (!opt_rx.mptcp.mp_join ||
@@ -294,11 +296,14 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 	if (child && *own_req) {
 		struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
 
-		/* we have null ctx on TCP fallback, not fatal on MPC
-		 * handshake
+		/* we have null ctx on TCP fallback, which is fatal on
+		 * MPJ handshake
 		 */
-		if (!ctx)
+		if (!ctx) {
+			if (fallback_is_fatal)
+				goto close_child;
 			return child;
+		}
 
 		if (ctx->mp_capable) {
 			if (mptcp_token_new_accept(ctx->token))
-- 
2.21.0