--- zzzz-none-000/linux-4.19.183/net/ipv4/tcp_fastopen.c	2021-03-24 10:07:39.000000000 +0000
+++ bcm63-7530ax-756/linux-4.19.183/net/ipv4/tcp_fastopen.c	2023-06-28 08:54:21.000000000 +0000
@@ -9,6 +9,9 @@
 #include <linux/rculist.h>
 #include <net/inetpeer.h>
 #include <net/tcp.h>
+#if defined(CONFIG_BCM_KF_MPTCP) && defined(CONFIG_BCM_MPTCP)
+#include <net/mptcp.h>
+#endif
 
 void tcp_fastopen_init_key_once(struct net *net)
 {
@@ -218,8 +221,15 @@
 {
 	struct tcp_sock *tp;
 	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
+#if !defined(CONFIG_BCM_KF_MPTCP) || !defined(CONFIG_BCM_MPTCP)
 	struct sock *child;
+#else
+	struct sock *child, *meta_sk;
+#endif
 	bool own_req;
+#if defined(CONFIG_BCM_KF_MPTCP) && defined(CONFIG_BCM_MPTCP)
+	int ret;
+#endif
 
 	req->num_retrans = 0;
 	req->num_timeout = 0;
@@ -258,15 +268,33 @@
 
 	refcount_set(&req->rsk_refcnt, 2);
 
+#if !defined(CONFIG_BCM_KF_MPTCP) || !defined(CONFIG_BCM_MPTCP)
 	/* Now finish processing the fastopen child socket. */
 	tcp_init_transfer(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
 
+#endif
 	tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
 
 	tcp_fastopen_add_skb(child, skb);
 
 	tcp_rsk(req)->rcv_nxt = tp->rcv_nxt;
 	tp->rcv_wup = tp->rcv_nxt;
+#if defined(CONFIG_BCM_KF_MPTCP) && defined(CONFIG_BCM_MPTCP)
+
+	meta_sk = child;
+	ret = mptcp_check_req_fastopen(meta_sk, req);
+	if (ret < 0)
+		return NULL;
+
+	if (ret == 0) {
+		child = tcp_sk(meta_sk)->mpcb->master_sk;
+		tp = tcp_sk(child);
+	}
+
+	/* Now finish processing the fastopen child socket. */
+	tcp_init_transfer(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
+
+#endif
 	/* tcp_conn_request() is sending the SYNACK,
 	 * and queues the child into listener accept queue.
 	 */