--- zzzz-none-000/linux-4.19.183/net/ipv4/ip_sockglue.c	2021-03-24 10:07:39.000000000 +0000
+++ bcm63-7530ax-756/linux-4.19.183/net/ipv4/ip_sockglue.c	2023-06-28 08:54:21.000000000 +0000
@@ -44,6 +44,10 @@
 #endif
 #include <net/ip_fib.h>
 
+#if defined(CONFIG_BCM_KF_MPTCP) && defined(CONFIG_BCM_MPTCP)
+#include <net/mptcp.h>
+
+#endif
 #include <linux/errqueue.h>
 #include <linux/uaccess.h>
 
@@ -655,7 +659,11 @@
 			break;
 		old = rcu_dereference_protected(inet->inet_opt,
 						lockdep_sock_is_held(sk));
+#if !defined(CONFIG_BCM_KF_MPTCP) || !defined(CONFIG_BCM_MPTCP)
 		if (inet->is_icsk) {
+#else
+		if (inet->is_icsk && !is_meta_sk(sk)) {
+#endif
 			struct inet_connection_sock *icsk = inet_csk(sk);
 #if IS_ENABLED(CONFIG_IPV6)
 			if (sk->sk_family == PF_INET ||
@@ -749,6 +757,22 @@
 			inet->tos = val;
 			sk->sk_priority = rt_tos2priority(val);
 			sk_dst_reset(sk);
+#if defined(CONFIG_BCM_KF_MPTCP) && defined(CONFIG_BCM_MPTCP)
+			/* Update TOS on mptcp subflow */
+			if (is_meta_sk(sk)) {
+				struct mptcp_tcp_sock *mptcp;
+
+				mptcp_for_each_sub(tcp_sk(sk)->mpcb, mptcp) {
+					struct sock *sk_it = mptcp_to_sock(mptcp);
+
+					if (inet_sk(sk_it)->tos != inet_sk(sk)->tos) {
+						inet_sk(sk_it)->tos = inet_sk(sk)->tos;
+						sk_it->sk_priority = sk->sk_priority;
+						sk_dst_reset(sk_it);
+					}
+				}
+			}
+#endif
 		}
 		break;
 	case IP_TTL: