--- /dev/null
+/* $OpenBSD: if_rport.c,v 1.1 2024/08/31 04:17:14 dlg Exp $ */
+
+/*
+ * 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;
+};
+
+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 int rport_set_parent(struct rport_softc *,
+ const struct if_parent *);
+static int rport_get_parent(struct rport_softc *, struct if_parent *);
+static int rport_del_parent(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);
+ rport_del_parent(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 ifqueue *ifq = &ifp->if_snd;
+ int error;
+
+ error = ifq_enqueue(ifq, m);
+ if (error)
+ return (error);
+
+ /*
+ * always defer handover of packets to the peer to the ifq
+ * bundle task to provide control over the NET_LOCK scope.
+ */
+ task_add(ifq->ifq_softnet, &ifq->ifq_bundle);
+
+ return (0);
+}
+
+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 *m;
+
+ ifp0 = if_get(sc->sc_peer_idx);
+ if (ifp0 == NULL || !ISSET(ifp0->if_flags, IFF_RUNNING)) {
+ ifq_purge(ifq);
+ if_put(ifp0);
+ return;
+ }
+
+ NET_LOCK_SHARED();
+ while ((m = ifq_dequeue(ifq)) != NULL) {
+#if NBPFILTER > 0
+ caddr_t 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
+
+ if_vinput(ifp0, m);
+ }
+ NET_UNLOCK_SHARED();
+
+ 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);
+
+ 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 == ifp) {
+ error = EINVAL;
+ goto leave;
+ }
+
+ if (ifp0->if_input != rport_input) {
+ error = EPROTONOSUPPORT;
+ goto put;
+ }
+
+ sc0 = ifp0->if_softc;
+
+ if (sc->sc_peer_idx == ifp0->if_index) {
+ /* nop */
+ KASSERT(sc0->sc_peer_idx == ifp->if_index);
+ goto put;
+ }
+
+ if (sc->sc_peer_idx != 0 || 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);
+}
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