Index: sys/net/if.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/net/if.c,v
diff -u -p -u -p -r1.722 if.c
--- sys/net/if.c	16 Jan 2025 17:20:23 -0000	1.722
+++ sys/net/if.c	20 Jan 2025 09:54:45 -0000
@@ -244,11 +244,6 @@ int	ifq_congestion;
 
 int		 netisr;
 
-struct softnet {
-	char		 sn_name[16];
-	struct taskq	*sn_taskq;
-};
-
 #define	NET_TASKQ	4
 struct softnet	softnets[NET_TASKQ];
 
@@ -978,9 +973,10 @@ if_output_local(struct ifnet *ifp, struc
 }
 
 void
-if_input_process(struct ifnet *ifp, struct mbuf_list *ml)
+if_input_process(struct ifnet *ifp, struct mbuf_list *ml, u_int idx)
 {
 	struct mbuf *m;
+	struct softnet *sn;
 
 	if (ml_empty(ml))
 		return;
@@ -995,10 +991,22 @@ if_input_process(struct ifnet *ifp, stru
 	 * read only or MP safe.  Usually they hold the exclusive net lock.
 	 */
 
+	sn = &softnets[idx];
+	ml_init(&sn->sn_tcp_ml);
+
 	NET_LOCK_SHARED();
-	while ((m = ml_dequeue(ml)) != NULL)
+	while ((m = ml_dequeue(ml)) != NULL) {
+		/* add 1 to index, 0 means not set */
+		m->m_pkthdr.ph_softidx = idx + 1;
 		(*ifp->if_input)(ifp, m);
+	}
 	NET_UNLOCK_SHARED();
+
+	if (!ml_empty(&sn->sn_tcp_ml)) {
+		NET_LOCK();
+		tcp_input_mlist(&sn->sn_tcp_ml);
+		NET_UNLOCK();
+	}
 }
 
 void
Index: sys/net/if_var.h
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/net/if_var.h,v
diff -u -p -u -p -r1.133 if_var.h
--- sys/net/if_var.h	12 Oct 2024 23:18:10 -0000	1.133
+++ sys/net/if_var.h	20 Jan 2025 09:54:45 -0000
@@ -292,6 +292,14 @@ struct ifg_list {
 #define IF_WWAN_DEFAULT_PRIORITY	6
 #define IF_CARP_DEFAULT_PRIORITY	15
 
+struct softnet {
+	char			 sn_name[16];
+	struct taskq		*sn_taskq;
+	struct mbuf_list	 sn_tcp_ml;
+};
+
+extern struct softnet	softnets[];
+
 /*
  * Network stack input queues.
  */
@@ -322,7 +330,7 @@ int	if_enqueue(struct ifnet *, struct mb
 int	if_enqueue_ifq(struct ifnet *, struct mbuf *);
 void	if_input(struct ifnet *, struct mbuf_list *);
 void	if_vinput(struct ifnet *, struct mbuf *);
-void	if_input_process(struct ifnet *, struct mbuf_list *);
+void	if_input_process(struct ifnet *, struct mbuf_list *, u_int);
 int	if_input_local(struct ifnet *, struct mbuf *, sa_family_t);
 int	if_output_ml(struct ifnet *, struct mbuf_list *,
 	    struct sockaddr *, struct rtentry *);
Index: sys/net/ifq.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/net/ifq.c,v
diff -u -p -u -p -r1.55 ifq.c
--- sys/net/ifq.c	20 Nov 2024 02:18:45 -0000	1.55
+++ sys/net/ifq.c	20 Jan 2025 09:54:45 -0000
@@ -849,7 +849,7 @@ ifiq_process(void *arg)
 	ml_init(&ifiq->ifiq_ml);
 	mtx_leave(&ifiq->ifiq_mtx);
 
-	if_input_process(ifiq->ifiq_if, &ml);
+	if_input_process(ifiq->ifiq_if, &ml, ifiq->ifiq_idx);
 }
 
 int
Index: sys/netinet/in_proto.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/netinet/in_proto.c,v
diff -u -p -u -p -r1.121 in_proto.c
--- sys/netinet/in_proto.c	5 Jan 2025 12:36:48 -0000	1.121
+++ sys/netinet/in_proto.c	20 Jan 2025 09:54:45 -0000
@@ -197,7 +197,8 @@ const struct protosw inetsw[] = {
   .pr_type	= SOCK_STREAM,
   .pr_domain	= &inetdomain,
   .pr_protocol	= IPPROTO_TCP,
-  .pr_flags	= PR_CONNREQUIRED|PR_WANTRCVD|PR_ABRTACPTDIS|PR_SPLICE,
+  .pr_flags	= PR_CONNREQUIRED|PR_WANTRCVD|PR_ABRTACPTDIS|PR_SPLICE|
+    PR_MPINPUT,
   .pr_input	= tcp_input,
   .pr_ctlinput	= tcp_ctlinput,
   .pr_ctloutput	= tcp_ctloutput,
Index: sys/netinet/tcp_input.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/netinet/tcp_input.c,v
diff -u -p -u -p -r1.423 tcp_input.c
--- sys/netinet/tcp_input.c	16 Jan 2025 11:59:20 -0000	1.423
+++ sys/netinet/tcp_input.c	20 Jan 2025 09:54:45 -0000
@@ -100,9 +100,6 @@
 #include <net/pfvar.h>
 #endif
 
-int tcp_mss_adv(struct mbuf *, int);
-int tcp_flush_queue(struct tcpcb *);
-
 #ifdef INET6
 #include <netinet6/in6_var.h>
 #include <netinet6/nd6.h>
@@ -177,6 +174,9 @@ do { \
 	if_put(ifp); \
 } while (0)
 
+int	 tcp_input_mbuf(struct mbuf **, int *, int, int);
+int	 tcp_mss_adv(struct mbuf *, int);
+int	 tcp_flush_queue(struct tcpcb *);
 void	 tcp_sack_partialack(struct tcpcb *, struct tcphdr *);
 void	 tcp_newreno_partialack(struct tcpcb *, struct tcphdr *);
 
@@ -347,12 +347,44 @@ tcp_flush_queue(struct tcpcb *tp)
 	return (flags);
 }
 
+int
+tcp_input(struct mbuf **mp, int *offp, int proto, int af)
+{
+	struct softnet *sn;
+
+	if ((*mp)->m_pkthdr.ph_softidx == 0)
+		return tcp_input_mbuf(mp, offp, proto, af);
+	sn = &softnets[(*mp)->m_pkthdr.ph_softidx - 1];
+	(*mp)->m_pkthdr.ph_softidx = 0;
+	(*mp)->m_pkthdr.ph_cookie = (void *)(long)(*offp);
+	(*mp)->m_pkthdr.ph_family = af;
+	ml_enqueue(&sn->sn_tcp_ml, *mp);
+	*mp = NULL;
+	return IPPROTO_DONE;
+}
+
+void
+tcp_input_mlist(struct mbuf_list *ml)
+{
+	struct mbuf *m;
+
+	while ((m = ml_dequeue(ml)) != NULL) {
+		int off, nxt, af;
+
+		off = (long)m->m_pkthdr.ph_cookie;
+		m->m_pkthdr.ph_cookie = NULL;
+		af = m->m_pkthdr.ph_family;
+		nxt = tcp_input_mbuf(&m, &off, IPPROTO_TCP, af);
+		KASSERT(nxt == IPPROTO_DONE);
+	}
+}
+
 /*
  * TCP input routine, follows pages 65-76 of the
  * protocol specification dated September, 1981 very closely.
  */
 int
-tcp_input(struct mbuf **mp, int *offp, int proto, int af)
+tcp_input_mbuf(struct mbuf **mp, int *offp, int proto, int af)
 {
 	struct mbuf *m = *mp;
 	int iphlen = *offp;
Index: sys/netinet/tcp_var.h
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/netinet/tcp_var.h,v
diff -u -p -u -p -r1.185 tcp_var.h
--- sys/netinet/tcp_var.h	16 Jan 2025 11:59:20 -0000	1.185
+++ sys/netinet/tcp_var.h	20 Jan 2025 09:54:45 -0000
@@ -718,6 +718,7 @@ int	 tcp_dooptions(struct tcpcb *, u_cha
 		struct mbuf *, int, struct tcp_opt_info *, u_int, uint64_t);
 void	 tcp_init(void);
 int	 tcp_input(struct mbuf **, int *, int, int);
+void	 tcp_input_mlist(struct mbuf_list *);
 int	 tcp_mss(struct tcpcb *, int);
 void	 tcp_mss_update(struct tcpcb *);
 u_int	 tcp_hdrsz(struct tcpcb *);
Index: sys/netinet6/in6_proto.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/netinet6/in6_proto.c,v
diff -u -p -u -p -r1.124 in6_proto.c
--- sys/netinet6/in6_proto.c	5 Jan 2025 12:36:48 -0000	1.124
+++ sys/netinet6/in6_proto.c	20 Jan 2025 09:54:45 -0000
@@ -147,7 +147,8 @@ const struct protosw inet6sw[] = {
   .pr_type	= SOCK_STREAM,
   .pr_domain	= &inet6domain,
   .pr_protocol	= IPPROTO_TCP,
-  .pr_flags	= PR_CONNREQUIRED|PR_WANTRCVD|PR_ABRTACPTDIS|PR_SPLICE,
+  .pr_flags	= PR_CONNREQUIRED|PR_WANTRCVD|PR_ABRTACPTDIS|PR_SPLICE|
+    PR_MPINPUT,
   .pr_input	= tcp_input,
   .pr_ctlinput	= tcp6_ctlinput,
   .pr_ctloutput	= tcp_ctloutput,
Index: sys/sys/mbuf.h
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/sys/mbuf.h,v
diff -u -p -u -p -r1.265 mbuf.h
--- sys/sys/mbuf.h	5 Nov 2024 13:15:13 -0000	1.265
+++ sys/sys/mbuf.h	20 Jan 2025 09:54:45 -0000
@@ -128,7 +128,7 @@ struct	pkthdr {
 	int64_t			 ph_timestamp;	/* packet timestamp */
 	int			 len;		/* total packet length */
 	u_int			 ph_rtableid;	/* routing table id */
-	u_int			 ph_ifidx;	/* rcv interface index */
+	u_int16_t		 ph_ifidx;	/* rcv interface index */
 	u_int16_t		 ph_tagsset;	/* mtags attached */
 	u_int16_t		 ph_flowid;	/* pseudo unique flow id */
 	u_int16_t		 csum_flags;	/* checksum flags */
@@ -136,6 +136,8 @@ struct	pkthdr {
 	u_int16_t		 ph_mss;	/* TCP max segment size */
 	u_int8_t		 ph_loopcnt;	/* mbuf is looping in kernel */
 	u_int8_t		 ph_family;	/* af, used when queueing */
+	u_int8_t		 ph_softidx;	/* index of softnet thread */
+	u_int8_t		 ph_pad[1];
 	struct pkthdr_pf	 pf;
 };