--- zzzz-none-000/linux-4.1.52/net/ipv4/ip_sockglue.c	2018-05-28 02:26:45.000000000 +0000
+++ bcm63-7530ax-731/linux-4.1.52/net/ipv4/ip_sockglue.c	2022-03-02 11:37:13.000000000 +0000
@@ -43,6 +43,10 @@
 #endif
 #include <net/ip_fib.h>
 
+#if defined(CONFIG_BCM_MPTCP) && defined(CONFIG_BCM_KF_MPTCP)
+#include <net/mptcp.h>
+
+#endif
 #include <linux/errqueue.h>
 #include <asm/uaccess.h>
 
@@ -722,6 +726,19 @@
 			inet->tos = val;
 			sk->sk_priority = rt_tos2priority(val);
 			sk_dst_reset(sk);
+#if defined(CONFIG_BCM_MPTCP) && defined(CONFIG_BCM_KF_MPTCP)
+			/* Update TOS on mptcp subflow */
+			if (is_meta_sk(sk)) {
+				struct sock *sk_it;
+				mptcp_for_each_sk(tcp_sk(sk)->mpcb, sk_it) {
+					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: