diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -55,6 +55,7 @@
 #include "opt_inet.h"
 #include "opt_inet6.h"
 #include "opt_ipsec.h"
+#include "opt_rss.h"
 
 #include <sys/param.h>
 #include <sys/arb.h>
@@ -83,6 +84,7 @@
 #include <net/if.h>
 #include <net/if_var.h>
 #include <net/route.h>
+#include <net/rss_config.h>
 #include <net/vnet.h>
 
 #define TCPSTATES		/* for logging */
@@ -90,6 +92,7 @@
 #include <netinet/in.h>
 #include <netinet/in_kdtrace.h>
 #include <netinet/in_pcb.h>
+#include <netinet/in_rss.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <netinet/ip_icmp.h>	/* required for icmp_var.h */
@@ -99,6 +102,7 @@
 #include <netinet/ip6.h>
 #include <netinet/icmp6.h>
 #include <netinet6/in6_pcb.h>
+#include <netinet6/in6_rss.h>
 #include <netinet6/in6_var.h>
 #include <netinet6/ip6_var.h>
 #include <netinet6/nd6.h>
@@ -936,10 +940,36 @@
 	INP_LOCK_ASSERT(inp);
 
 	if ((inp->inp_flowtype == M_HASHTYPE_NONE) &&
-	    (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) &&
 	    !SOLISTENING(inp->inp_socket)) {
-		inp->inp_flowid = m->m_pkthdr.flowid;
-		inp->inp_flowtype = M_HASHTYPE_GET(m);
+		if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) {
+			inp->inp_flowid = m->m_pkthdr.flowid;
+			inp->inp_flowtype = M_HASHTYPE_GET(m);
+		}
+#ifdef	RSS
+		  else {
+			  /* assign flowid by software RSS hash */
+#ifdef INET6
+			  if (isipv6) {
+				rss_proto_software_hash_v6(&inp->in6p_faddr,
+							   &inp->in6p_laddr,
+							   inp->inp_fport,
+							   inp->inp_lport,
+							   IPPROTO_TCP,
+							   &inp->inp_flowid,
+							   &inp->inp_flowtype);
+			  } else
+#endif	/* INET6 */
+			  {
+				rss_proto_software_hash_v4(inp->inp_faddr,
+							   inp->inp_laddr,
+							   inp->inp_fport,
+							   inp->inp_lport,
+							   IPPROTO_TCP,
+							   &inp->inp_flowid,
+							   &inp->inp_flowtype);
+			  }
+		}
+#endif	/* RSS */
 	}
 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
 #ifdef INET6