Index: net/if_rport.c
===================================================================
RCS file: net/if_rport.c
diff -N net/if_rport.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ net/if_rport.c	4 Jan 2023 06:41:37 -0000
@@ -0,0 +1,475 @@
+/*	$OpenBSD$ */
+
+/*
+ * Copyright (c) 2023 David Gwynne <dlg@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/sockio.h>
+#include <sys/syslog.h>
+#include <sys/queue.h>
+
+#include <net/if.h>
+#include <net/if_var.h>
+#include <net/if_types.h>
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_var.h>
+#include <netinet/ip.h>
+#include <netinet/ip_var.h>
+#include <netinet/ip_ipip.h>
+#include <netinet/ip_ecn.h>
+
+#ifdef INET6
+#include <netinet6/in6_var.h>
+#include <netinet/ip6.h>
+#include <netinet6/ip6_var.h>
+#endif /* INET6 */
+
+#include "bpfilter.h"
+#if NBPFILTER > 0
+#include <net/bpf.h>
+#endif
+
+#ifdef MPLS
+#include <netmpls/mpls.h>
+#endif
+
+#include "pf.h"
+#if NPF > 0
+#include <net/pfvar.h>
+#endif
+
+#define RPORT_MTU_MIN		1280
+#define RPORT_MTU_MAX		32768 /* LOMTU, but could be higher */
+#define RPORT_MTU_DEFAULT	RPORT_MTU_MAX
+
+struct rport_softc {
+	struct ifnet			 sc_if;
+
+	unsigned int			 sc_peer_idx;
+	struct task			 sc_peer_ltask;
+	struct task			 sc_peer_dtask;
+};
+
+static int	rport_clone_create(struct if_clone *, int);
+static int	rport_clone_destroy(struct ifnet *);
+
+static int	rport_ioctl(struct ifnet *, u_long, caddr_t);
+static int	rport_output(struct ifnet *, struct mbuf *, struct sockaddr *,
+		    struct rtentry *);
+static int	rport_enqueue(struct ifnet *, struct mbuf *);
+static void	rport_start(struct ifqueue *);
+static void	rport_input(struct ifnet *, struct mbuf *);
+
+static int	rport_up(struct rport_softc *);
+static int	rport_down(struct rport_softc *);
+
+static struct if_clone rport_cloner =
+    IF_CLONE_INITIALIZER("rport", rport_clone_create, rport_clone_destroy);
+
+static struct rwlock rport_interfaces_lock =
+    RWLOCK_INITIALIZER("rports");
+
+void
+rportattach(int count)
+{
+	if_clone_attach(&rport_cloner);
+}
+
+static int
+rport_clone_create(struct if_clone *ifc, int unit)
+{
+	struct rport_softc *sc;
+	struct ifnet *ifp;
+
+	sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
+	ifp = &sc->sc_if;
+
+	snprintf(ifp->if_xname, sizeof(ifp->if_xname),
+	    "%s%d", ifc->ifc_name, unit);
+
+	ifp->if_mtu = RPORT_MTU_DEFAULT;
+	ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
+	ifp->if_xflags = IFXF_CLONED | IFXF_MPSAFE;
+	ifp->if_ioctl = rport_ioctl;
+	ifp->if_bpf_mtap = p2p_bpf_mtap;
+	ifp->if_output = rport_output;
+	ifp->if_enqueue = rport_enqueue;
+	ifp->if_qstart = rport_start;
+	ifp->if_input = rport_input;
+	ifp->if_rtrequest = p2p_rtrequest;
+	ifp->if_type = IFT_TUNNEL;
+	ifp->if_softc = sc;
+
+	if_attach(ifp);
+	if_alloc_sadl(ifp);
+	if_counters_alloc(ifp);
+
+#if NBPFILTER > 0
+	bpfattach(&ifp->if_bpf, ifp, DLT_LOOP, sizeof(uint32_t));
+#endif
+
+	return (0);
+}
+
+int
+rport_clone_destroy(struct ifnet *ifp)
+{
+	struct rport_softc *sc = ifp->if_softc;
+
+	NET_LOCK();
+	if (ISSET(ifp->if_flags, IFF_RUNNING))
+		rport_down(sc);
+	NET_UNLOCK();
+
+	if_detach(ifp);
+
+	free(sc, M_DEVBUF, sizeof(*sc));
+
+	return (0);
+}
+
+static int
+rport_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
+    struct rtentry *rt)
+{
+	struct m_tag *mtag;
+	int error = 0;
+
+	if (!ISSET(ifp->if_flags, IFF_RUNNING)) {
+		error = ENETDOWN;
+		goto drop;
+	}
+
+	switch (dst->sa_family) {
+	case AF_INET:
+#ifdef INET6
+	case AF_INET6:
+#endif
+#ifdef MPLS
+	case AF_MPLS:
+#endif
+		break;
+	default:
+		error = EAFNOSUPPORT;
+		goto drop;
+	}
+
+	/* Try to limit infinite recursion through misconfiguration. */
+	mtag = NULL;
+	while ((mtag = m_tag_find(m, PACKET_TAG_GRE, mtag)) != NULL) {
+		if (*(int *)(mtag + 1) == ifp->if_index) {
+			error = EIO;
+			goto drop;
+		}
+	}
+
+	mtag = m_tag_get(PACKET_TAG_GRE, sizeof(ifp->if_index), M_NOWAIT);
+	if (mtag == NULL) {
+		error = ENOBUFS;
+		goto drop;
+	}
+	*(int *)(mtag + 1) = ifp->if_index;
+	m_tag_prepend(m, mtag);
+
+	m->m_flags &= ~(M_BCAST|M_MCAST);
+	m->m_pkthdr.ph_family = dst->sa_family;
+#if NPF > 0
+	pf_pkt_addr_changed(m);
+#endif
+
+	error = if_enqueue(ifp, m);
+	if (error)
+		counters_inc(ifp->if_counters, ifc_oerrors);
+
+	return (error);
+
+drop:
+	m_freem(m);
+	return (error);
+}
+
+static int
+rport_enqueue(struct ifnet *ifp, struct mbuf *m)
+{
+	struct rport_softc *sc;
+	struct ifnet *ifp0;
+#if NBPFILTER > 0
+	caddr_t if_bpf;
+#endif
+	int error = 0;
+
+	if (!ifq_is_priq(&ifp->if_snd))
+		return (if_enqueue_ifq(ifp, m));
+
+	sc = ifp->if_softc;
+	ifp0 = if_get(sc->sc_peer_idx);
+	if (ifp0 == NULL || !ISSET(ifp0->if_flags, IFF_RUNNING)) {
+		m_freem(m);
+		error = ENETDOWN;
+	} else {
+		counters_pkt(ifp->if_counters,
+		    ifc_opackets, ifc_obytes, m->m_pkthdr.len);
+
+#if NBPFILTER > 0
+		if_bpf = READ_ONCE(ifp->if_bpf);
+		if (if_bpf && bpf_mtap_af(if_bpf, m->m_pkthdr.ph_family,
+		    m, BPF_DIRECTION_OUT))
+			m_freem(m);
+		else
+#endif
+			ifiq_enqueue(&ifp0->if_rcv, m);
+	}
+	if_put(ifp0);
+
+	return (error);
+}
+
+static void
+rport_start(struct ifqueue *ifq)
+{
+	struct ifnet *ifp = ifq->ifq_if;
+	struct rport_softc *sc = ifp->if_softc;
+	struct ifnet *ifp0;
+	struct mbuf_list ml = MBUF_LIST_INITIALIZER();
+	struct mbuf *m;
+#if NBPFILTER > 0
+	caddr_t if_bpf;
+#endif
+
+	ifp0 = if_get(sc->sc_peer_idx);
+	if (ifp0 == NULL || !ISSET(ifp0->if_flags, IFF_RUNNING)) {
+		ifq_purge(ifq);
+		if_put(ifp0);
+		return;
+	}
+
+	while ((m = ifq_dequeue(ifq)) != NULL) {
+#if NBPFILTER > 0
+		if_bpf = READ_ONCE(ifp->if_bpf);
+		if (if_bpf && bpf_mtap_af(if_bpf, m->m_pkthdr.ph_family,
+		    m, BPF_DIRECTION_OUT)) {
+			m_freem(m);
+			continue;
+		}
+#endif
+
+		ml_enqueue(&ml, m);
+	}
+
+	ifiq_input(&ifp0->if_rcv, &ml);
+
+	if_put(ifp0);
+}
+
+static void
+rport_input(struct ifnet *ifp, struct mbuf *m)
+{
+        switch (m->m_pkthdr.ph_family) {
+        case AF_INET:
+                ipv4_input(ifp, m);
+                break;
+#ifdef INET6
+        case AF_INET6:
+                ipv6_input(ifp, m);
+                break;
+#endif
+#ifdef MPLS
+        case AF_MPLS:
+                mpls_input(ifp, m);
+                break;
+#endif
+        default:
+		counters_inc(ifp->if_counters, ifc_noproto);
+                m_freem(m);
+                break;
+        }
+}
+
+static int
+rport_up(struct rport_softc *sc)
+{
+	NET_ASSERT_LOCKED();
+
+	SET(sc->sc_if.if_flags, IFF_RUNNING);
+
+	return (0);
+}
+
+static int
+rport_down(struct rport_softc *sc)
+{
+	NET_ASSERT_LOCKED();
+
+	CLR(sc->sc_if.if_flags, IFF_RUNNING);
+
+	/* barrier? */
+
+	return (0);
+}
+
+static int
+rport_set_parent(struct rport_softc *sc, const struct if_parent *p)
+{
+	struct ifnet *ifp = &sc->sc_if;
+	struct ifnet *ifp0;
+	struct rport_softc *sc0;
+	int error;
+
+	error = rw_enter(&rport_interfaces_lock, RW_WRITE | RW_INTR);
+	if (error != 0)
+		return (error);
+
+	ifp0 = if_unit(p->ifp_parent);
+	if (ifp0 == NULL) {
+		error = EINVAL;
+		goto leave;
+	}
+
+	if (ifp0->if_input != rport_input) {
+		error = EPROTONOSUPPORT;
+		goto put;
+	}
+
+	if (ifp0 == ifp) {
+		error = EINVAL;
+		goto leave;
+	}
+
+	sc0 = ifp0->if_softc;
+
+	if (sc->sc_peer_idx == ifp0->if_index) {
+		/* nop */
+		KASSERT(sc0->sc_peer_idx == ifp->if_index);
+		goto put;
+	}
+
+	if (sc0->sc_peer_idx != 0) {
+		error = EBUSY;
+		goto put;
+	}
+
+	/* commit */
+	sc->sc_peer_idx = ifp0->if_index;
+	sc0->sc_peer_idx = ifp->if_index;
+
+put:
+	if_put(ifp0);
+leave:
+	rw_exit(&rport_interfaces_lock);
+
+	return (error);
+}
+
+static int
+rport_get_parent(struct rport_softc *sc, struct if_parent *p)
+{
+	struct ifnet *ifp0;
+	int error = 0;
+
+	ifp0 = if_get(sc->sc_peer_idx);
+	if (ifp0 == NULL)
+		error = EADDRNOTAVAIL;
+	else {
+		if (strlcpy(p->ifp_parent, ifp0->if_xname,
+		    sizeof(p->ifp_parent)) >= sizeof(p->ifp_parent))
+			panic("%s strlcpy", __func__);
+	}
+	if_put(ifp0);
+
+	return (error);
+}
+
+static int
+rport_del_parent(struct rport_softc *sc)
+{
+	struct rport_softc *sc0;
+	struct ifnet *ifp0;
+	int error;
+
+	error = rw_enter(&rport_interfaces_lock, RW_WRITE | RW_INTR);
+	if (error != 0)
+		return (error);
+
+	ifp0 = if_get(sc->sc_peer_idx);
+	sc->sc_peer_idx = 0;
+
+	if (ifp0 != NULL) {
+		sc0 = ifp0->if_softc;
+		sc0->sc_peer_idx = 0;
+	}
+	if_put(ifp0);
+
+	rw_exit(&rport_interfaces_lock);
+
+	return (0);
+}
+
+static int
+rport_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
+{
+	struct rport_softc *sc = ifp->if_softc;
+	struct ifreq *ifr = (struct ifreq *)data;
+	int error = 0;
+
+	switch (cmd) {
+	case SIOCSIFADDR:
+		break;
+	case SIOCSIFFLAGS:
+		if (ISSET(ifp->if_flags, IFF_UP)) {
+			if (!ISSET(ifp->if_flags, IFF_RUNNING))
+				error = rport_up(sc);
+		} else {
+			if (ISSET(ifp->if_flags, IFF_RUNNING))
+				error = rport_down(sc);
+		}
+		break;
+
+	case SIOCADDMULTI:
+	case SIOCDELMULTI:
+		break;
+
+	case SIOCSIFMTU:
+		if (ifr->ifr_mtu < RPORT_MTU_MIN ||
+		    ifr->ifr_mtu > RPORT_MTU_MAX) {
+			error = EINVAL;
+			break;
+		}
+
+		ifp->if_mtu = ifr->ifr_mtu;
+		break;
+
+	case SIOCSIFPARENT:
+		error = rport_set_parent(sc, (struct if_parent *)data);
+		break;
+	case SIOCGIFPARENT:
+		error = rport_get_parent(sc, (struct if_parent *)data);
+		break;
+	case SIOCDIFPARENT:
+		error = rport_del_parent(sc);
+		break;
+
+	default:
+		error = ENOTTY;
+		break;
+	}
+
+	return (error);
+}
Index: conf/GENERIC
===================================================================
RCS file: /cvs/src/sys/conf/GENERIC,v
retrieving revision 1.286
diff -u -p -r1.286 GENERIC
--- conf/GENERIC	30 Sep 2022 02:56:23 -0000	1.286
+++ conf/GENERIC	4 Jan 2023 06:41:37 -0000
@@ -96,6 +96,7 @@ pseudo-device	mpe		# MPLS PE interface
 pseudo-device	mpw		# MPLS pseudowire support
 pseudo-device	mpip		# MPLS IP Layer2 pseudowire support
 pseudo-device	bpe		# Provider Backbone Bridge edge interface
+pseudo-device	rport		# rdomain port interface
 pseudo-device	pair		# Virtual Ethernet interface pair
 pseudo-device	ppp		# PPP
 pseudo-device	pppoe		# PPP over Ethernet (RFC 2516)
Index: conf/files
===================================================================
RCS file: /cvs/src/sys/conf/files,v
retrieving revision 1.720
diff -u -p -r1.720 files
--- conf/files	22 Dec 2022 05:59:26 -0000	1.720
+++ conf/files	4 Jan 2023 06:41:37 -0000
@@ -547,6 +547,7 @@ pseudo-device msts: tty
 pseudo-device endrun: tty
 
 pseudo-device loop: ifnet
+pseudo-device rport: ifnet
 pseudo-device pair: ifnet, ether
 pseudo-device ppp: ifnet
 pseudo-device tun: ifnet
@@ -833,6 +834,7 @@ file net/if_mpw.c			mpw
 file net/if_mpip.c			mpip
 file net/if_bpe.c			bpe			needs-count
 file net/if_vether.c			vether
+file net/if_rport.c			rport
 file net/if_pair.c			pair
 file net/if_pppx.c			pppx			needs-count
 file net/if_vxlan.c			vxlan			needs-count