--- zzzz-none-000/linux-4.1.38/net/ipv4/tcp_fastopen.c	2017-01-18 18:48:06.000000000 +0000
+++ bcm63-7582-715/linux-4.1.38/net/ipv4/tcp_fastopen.c	2020-11-25 10:06:48.000000000 +0000
@@ -7,6 +7,9 @@
 #include <linux/rculist.h>
 #include <net/inetpeer.h>
 #include <net/tcp.h>
+#if defined(CONFIG_BCM_MPTCP) && defined(CONFIG_BCM_KF_MPTCP)
+#include <net/mptcp.h>
+#endif
 
 int sysctl_tcp_fastopen __read_mostly = TFO_CLIENT_ENABLE;
 
@@ -131,7 +134,11 @@
 {
 	struct tcp_sock *tp;
 	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
+#if !defined(CONFIG_BCM_MPTCP) || !defined(CONFIG_BCM_KF_MPTCP)
 	struct sock *child;
+#else
+	struct sock *child, *meta_sk;
+#endif
 	u32 end_seq;
 
 	req->num_retrans = 0;
@@ -171,6 +178,7 @@
 	/* Add the child socket directly into the accept queue */
 	inet_csk_reqsk_queue_add(sk, req, child);
 
+#if !defined(CONFIG_BCM_MPTCP) || !defined(CONFIG_BCM_KF_MPTCP)
 	/* Now finish processing the fastopen child socket. */
 	inet_csk(child)->icsk_af_ops->rebuild_header(child);
 	tcp_init_congestion_control(child);
@@ -178,6 +186,7 @@
 	tcp_init_metrics(child);
 	tcp_init_buffer_space(child);
 
+#endif
 	/* Queue the data carried in the SYN packet. We need to first
 	 * bump skb's refcnt because the caller will attempt to free it.
 	 * Note that IPv6 might also have used skb_get() trick
@@ -214,8 +223,30 @@
 		}
 	}
 	tcp_rsk(req)->rcv_nxt = tp->rcv_nxt = end_seq;
+#if defined(CONFIG_BCM_MPTCP) && defined(CONFIG_BCM_KF_MPTCP)
+
+	meta_sk = child;
+	if (!mptcp_check_req_fastopen(meta_sk, req)) {
+		child = tcp_sk(meta_sk)->mpcb->master_sk;
+		tp = tcp_sk(child);
+	}
+
+	/* Now finish processing the fastopen child socket. */
+	inet_csk(child)->icsk_af_ops->rebuild_header(child);
+	tcp_init_congestion_control(child);
+	tcp_mtup_init(child);
+	tcp_init_metrics(child);
+	tp->ops->init_buffer_space(child);
+
+#endif
 	sk->sk_data_ready(sk);
+#if !defined(CONFIG_BCM_MPTCP) || !defined(CONFIG_BCM_KF_MPTCP)
 	bh_unlock_sock(child);
+#else
+	if (mptcp(tcp_sk(child)))
+		bh_unlock_sock(child);
+	bh_unlock_sock(meta_sk);
+#endif
 	sock_put(child);
 	WARN_ON(!req->sk);
 	return true;