/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_netgraph.h"
#include "opt_mbuf_profiling.h"
#include "opt_rss.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/devctl.h>
#include <sys/eventhandler.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/msan.h>
#include <sys/proc.h>
#include <sys/priv.h>
#include <sys/random.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/uuid.h>
#ifdef KDB
#include <sys/kdb.h>
#endif

#include <net/ieee_oui.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_private.h>
#include <net/if_arp.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/if_llc.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if_bridgevar.h>
#include <net/if_vlan_var.h>
#include <net/if_llatbl.h>
#include <net/pfil.h>
#include <net/rss_config.h>
#include <net/vnet.h>

#include <netpfil/pf/pf_mtag.h>

#if defined(INET) || defined(INET6)
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>
#include <netinet/ip_carp.h>
#include <netinet/ip_var.h>
#endif
#ifdef INET6
#include <netinet6/nd6.h>
#endif
#include <security/mac/mac_framework.h>

#include <crypto/sha1.h>

VNET_DEFINE(pfil_head_t, link_pfil_head);       /* Packet filter hooks */

/* netgraph node hooks for ng_ether(4) */
void    (*ng_ether_input_p)(struct ifnet *ifp, struct mbuf **mp);
void    (*ng_ether_input_orphan_p)(struct ifnet *ifp, struct mbuf *m);
int     (*ng_ether_output_p)(struct ifnet *ifp, struct mbuf **mp);

/* if_bridge(4) support */
void    (*bridge_dn_p)(struct mbuf *, struct ifnet *);
bool    (*bridge_same_p)(const void *, const void *);
void    *(*bridge_get_softc_p)(struct ifnet *);
bool    (*bridge_member_ifaddrs_p)(void);

/* if_lagg(4) support */
struct mbuf *(*lagg_input_ethernet_p)(struct ifnet *, struct mbuf *); 

static const u_char etherbroadcastaddr[ETHER_ADDR_LEN] =
                        { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

static  int ether_resolvemulti(struct ifnet *, struct sockaddr **,
                struct sockaddr *);
static  int ether_requestencap(struct ifnet *, struct if_encap_req *);

static inline bool ether_do_pcp(struct ifnet *, struct mbuf *);

#define senderr(e) do { error = (e); goto bad;} while (0)

static void
update_mbuf_csumflags(struct mbuf *src, struct mbuf *dst)
{
        int csum_flags = 0;

        if (src->m_pkthdr.csum_flags & CSUM_IP)
                csum_flags |= (CSUM_IP_CHECKED|CSUM_IP_VALID);
        if (src->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
                csum_flags |= (CSUM_DATA_VALID|CSUM_PSEUDO_HDR);
        if (src->m_pkthdr.csum_flags & CSUM_SCTP)
                csum_flags |= CSUM_SCTP_VALID;
        dst->m_pkthdr.csum_flags |= csum_flags;
        if (csum_flags & CSUM_DATA_VALID)
                dst->m_pkthdr.csum_data = 0xffff;
}

/*
 * Handle link-layer encapsulation requests.
 */
static int
ether_requestencap(struct ifnet *ifp, struct if_encap_req *req)
{
        struct ether_header *eh;
        struct arphdr *ah;
        uint16_t etype;
        const u_char *lladdr;

        if (req->rtype != IFENCAP_LL)
                return (EOPNOTSUPP);

        if (req->bufsize < ETHER_HDR_LEN)
                return (ENOMEM);

        eh = (struct ether_header *)req->buf;
        lladdr = req->lladdr;
        req->lladdr_off = 0;

        switch (req->family) {
        case AF_INET:
                etype = htons(ETHERTYPE_IP);
                break;
        case AF_INET6:
                etype = htons(ETHERTYPE_IPV6);
                break;
        case AF_ARP:
                ah = (struct arphdr *)req->hdata;
                ah->ar_hrd = htons(ARPHRD_ETHER);

                switch(ntohs(ah->ar_op)) {
                case ARPOP_REVREQUEST:
                case ARPOP_REVREPLY:
                        etype = htons(ETHERTYPE_REVARP);
                        break;
                case ARPOP_REQUEST:
                case ARPOP_REPLY:
                default:
                        etype = htons(ETHERTYPE_ARP);
                        break;
                }

                if (req->flags & IFENCAP_FLAG_BROADCAST)
                        lladdr = ifp->if_broadcastaddr;
                break;
        default:
                return (EAFNOSUPPORT);
        }

        memcpy(&eh->ether_type, &etype, sizeof(eh->ether_type));
        memcpy(eh->ether_dhost, lladdr, ETHER_ADDR_LEN);
        memcpy(eh->ether_shost, IF_LLADDR(ifp), ETHER_ADDR_LEN);
        req->bufsize = sizeof(struct ether_header);

        return (0);
}

static int
ether_resolve_addr(struct ifnet *ifp, struct mbuf *m,
        const struct sockaddr *dst, struct route *ro, u_char *phdr,
        uint32_t *pflags, struct llentry **plle)
{
        uint32_t lleflags = 0;
        int error = 0;
#if defined(INET) || defined(INET6)
        struct ether_header *eh = (struct ether_header *)phdr;
        uint16_t etype;
#endif

        if (plle)
                *plle = NULL;

        switch (dst->sa_family) {
#ifdef INET
        case AF_INET:
                if ((m->m_flags & (M_BCAST | M_MCAST)) == 0)
                        error = arpresolve(ifp, 0, m, dst, phdr, &lleflags,
                            plle);
                else {
                        if (m->m_flags & M_BCAST)
                                memcpy(eh->ether_dhost, ifp->if_broadcastaddr,
                                    ETHER_ADDR_LEN);
                        else {
                                const struct in_addr *a;
                                a = &(((const struct sockaddr_in *)dst)->sin_addr);
                                ETHER_MAP_IP_MULTICAST(a, eh->ether_dhost);
                        }
                        etype = htons(ETHERTYPE_IP);
                        memcpy(&eh->ether_type, &etype, sizeof(etype));
                        memcpy(eh->ether_shost, IF_LLADDR(ifp), ETHER_ADDR_LEN);
                }
                break;
#endif
#ifdef INET6
        case AF_INET6:
                if ((m->m_flags & M_MCAST) == 0) {
                        int af = RO_GET_FAMILY(ro, dst);
                        error = nd6_resolve(ifp, LLE_SF(af, 0), m, dst, phdr,
                            &lleflags, plle);
                } else {
                        const struct in6_addr *a6;
                        a6 = &(((const struct sockaddr_in6 *)dst)->sin6_addr);
                        ETHER_MAP_IPV6_MULTICAST(a6, eh->ether_dhost);
                        etype = htons(ETHERTYPE_IPV6);
                        memcpy(&eh->ether_type, &etype, sizeof(etype));
                        memcpy(eh->ether_shost, IF_LLADDR(ifp), ETHER_ADDR_LEN);
                }
                break;
#endif
        default:
                if_printf(ifp, "can't handle af%d\n", dst->sa_family);
                if (m != NULL)
                        m_freem(m);
                return (EAFNOSUPPORT);
        }

        if (error == EHOSTDOWN) {
                if (ro != NULL && (ro->ro_flags & RT_HAS_GW) != 0)
                        error = EHOSTUNREACH;
        }

        if (error != 0)
                return (error);

        *pflags = RT_MAY_LOOP;
        if (lleflags & LLE_IFADDR)
                *pflags |= RT_L2_ME;

        return (0);
}

/*
 * Ethernet output routine.
 * Encapsulate a packet of type family for the local net.
 * Use trailer local net encapsulation if enough data in first
 * packet leaves a multiple of 512 bytes of data in remainder.
 */
int
ether_output(struct ifnet *ifp, struct mbuf *m,
        const struct sockaddr *dst, struct route *ro)
{
        int error = 0;
        char linkhdr[ETHER_HDR_LEN], *phdr;
        struct ether_header *eh;
        struct pf_mtag *t;
        bool loop_copy;
        int hlen;       /* link layer header length */
        uint32_t pflags;
        struct llentry *lle = NULL;
        int addref = 0;

        phdr = NULL;
        pflags = 0;
        if (ro != NULL) {
                /* XXX BPF uses ro_prepend */
                if (ro->ro_prepend != NULL) {
                        phdr = ro->ro_prepend;
                        hlen = ro->ro_plen;
                } else if (!(m->m_flags & (M_BCAST | M_MCAST))) {
                        if ((ro->ro_flags & RT_LLE_CACHE) != 0) {
                                lle = ro->ro_lle;
                                if (lle != NULL &&
                                    (lle->la_flags & LLE_VALID) == 0) {
                                        LLE_FREE(lle);
                                        lle = NULL;     /* redundant */
                                        ro->ro_lle = NULL;
                                }
                                if (lle == NULL) {
                                        /* if we lookup, keep cache */
                                        addref = 1;
                                } else
                                        /*
                                         * Notify LLE code that
                                         * the entry was used
                                         * by datapath.
                                         */
                                        llentry_provide_feedback(lle);
                        }
                        if (lle != NULL) {
                                phdr = lle->r_linkdata;
                                hlen = lle->r_hdrlen;
                                pflags = lle->r_flags;
                        }
                }
        }

#ifdef MAC
        error = mac_ifnet_check_transmit(ifp, m);
        if (error)
                senderr(error);
#endif

        M_PROFILE(m);
        if (ifp->if_flags & IFF_MONITOR)
                senderr(ENETDOWN);
        if (!((ifp->if_flags & IFF_UP) &&
            (ifp->if_drv_flags & IFF_DRV_RUNNING)))
                senderr(ENETDOWN);

        if (phdr == NULL) {
                /* No prepend data supplied. Try to calculate ourselves. */
                phdr = linkhdr;
                hlen = ETHER_HDR_LEN;
                error = ether_resolve_addr(ifp, m, dst, ro, phdr, &pflags,
                    addref ? &lle : NULL);
                if (addref && lle != NULL)
                        ro->ro_lle = lle;
                if (error != 0)
                        return (error == EWOULDBLOCK ? 0 : error);
        }

        if ((pflags & RT_L2_ME) != 0) {
                update_mbuf_csumflags(m, m);
                return (if_simloop(ifp, m, RO_GET_FAMILY(ro, dst), 0));
        }
        loop_copy = (pflags & RT_MAY_LOOP) != 0;

        /*
         * Add local net header.  If no space in first mbuf,
         * allocate another.
         *
         * Note that we do prepend regardless of RT_HAS_HEADER flag.
         * This is done because BPF code shifts m_data pointer
         * to the end of ethernet header prior to calling if_output().
         */
        M_PREPEND(m, hlen, M_NOWAIT);
        if (m == NULL)
                senderr(ENOBUFS);
        if ((pflags & RT_HAS_HEADER) == 0) {
                eh = mtod(m, struct ether_header *);
                memcpy(eh, phdr, hlen);
        }

        /*
         * If a simplex interface, and the packet is being sent to our
         * Ethernet address or a broadcast address, loopback a copy.
         * XXX To make a simplex device behave exactly like a duplex
         * device, we should copy in the case of sending to our own
         * ethernet address (thus letting the original actually appear
         * on the wire). However, we don't do that here for security
         * reasons and compatibility with the original behavior.
         */
        if ((m->m_flags & M_BCAST) && loop_copy && (ifp->if_flags & IFF_SIMPLEX) &&
            ((t = pf_find_mtag(m)) == NULL || !t->routed)) {
                struct mbuf *n;

                /*
                 * Because if_simloop() modifies the packet, we need a
                 * writable copy through m_dup() instead of a readonly
                 * one as m_copy[m] would give us. The alternative would
                 * be to modify if_simloop() to handle the readonly mbuf,
                 * but performancewise it is mostly equivalent (trading
                 * extra data copying vs. extra locking).
                 *
                 * XXX This is a local workaround.  A number of less
                 * often used kernel parts suffer from the same bug.
                 * See PR kern/105943 for a proposed general solution.
                 */
                if ((n = m_dup(m, M_NOWAIT)) != NULL) {
                        update_mbuf_csumflags(m, n);
                        (void)if_simloop(ifp, n, RO_GET_FAMILY(ro, dst), hlen);
                } else
                        if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
        }

       /*
        * Bridges require special output handling.
        */
        if (ifp->if_bridge) {
                BRIDGE_OUTPUT(ifp, m, error);
                return (error);
        }

#if defined(INET) || defined(INET6)
        if (ifp->if_carp &&
            (error = (*carp_output_p)(ifp, m, dst)))
                goto bad;
#endif

        /* Handle ng_ether(4) processing, if any */
        if (ifp->if_l2com != NULL) {
                KASSERT(ng_ether_output_p != NULL,
                    ("ng_ether_output_p is NULL"));
                if ((error = (*ng_ether_output_p)(ifp, &m)) != 0) {
bad:                    if (m != NULL)
                                m_freem(m);
                        return (error);
                }
                if (m == NULL)
                        return (0);
        }

        /* Continue with link-layer output */
        return ether_output_frame(ifp, m);
}

static bool
ether_set_pcp(struct mbuf **mp, struct ifnet *ifp, uint8_t pcp)
{
        struct ether_8021q_tag qtag;
        struct ether_header *eh;

        eh = mtod(*mp, struct ether_header *);
        if (eh->ether_type == htons(ETHERTYPE_VLAN) ||
            eh->ether_type == htons(ETHERTYPE_QINQ)) {
                (*mp)->m_flags &= ~M_VLANTAG;
                return (true);
        }

        qtag.vid = 0;
        qtag.pcp = pcp;
        qtag.proto = ETHERTYPE_VLAN;
        if (ether_8021q_frame(mp, ifp, ifp, &qtag))
                return (true);
        if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
        return (false);
}

/*
 * Ethernet link layer output routine to send a raw frame to the device.
 *
 * This assumes that the 14 byte Ethernet header is present and contiguous
 * in the first mbuf (if BRIDGE'ing).
 */
int
ether_output_frame(struct ifnet *ifp, struct mbuf *m)
{
        if (ether_do_pcp(ifp, m) && !ether_set_pcp(&m, ifp, ifp->if_pcp))
                return (0);

        if (PFIL_HOOKED_OUT(V_link_pfil_head))
                switch (pfil_mbuf_out(V_link_pfil_head, &m, ifp, NULL)) {
                case PFIL_DROPPED:
                        return (EACCES);
                case PFIL_CONSUMED:
                        return (0);
                }

#ifdef EXPERIMENTAL
#if defined(INET6) && defined(INET)
        /* draft-ietf-6man-ipv6only-flag */
        /* Catch ETHERTYPE_IP, and ETHERTYPE_[REV]ARP if we are v6-only. */
        if ((ifp->if_inet6->nd_flags & ND6_IFF_IPV6_ONLY_MASK) != 0) {
                struct ether_header *eh;

                eh = mtod(m, struct ether_header *);
                switch (ntohs(eh->ether_type)) {
                case ETHERTYPE_IP:
                case ETHERTYPE_ARP:
                case ETHERTYPE_REVARP:
                        m_freem(m);
                        return (EAFNOSUPPORT);
                        /* NOTREACHED */
                        break;
                };
        }
#endif
#endif

        /*
         * Queue message on interface, update output statistics if successful,
         * and start output if interface not yet active.
         *
         * If KMSAN is enabled, use it to verify that the data does not contain
         * any uninitialized bytes.
         */
        kmsan_check_mbuf(m, "ether_output");
        return ((ifp->if_transmit)(ifp, m));
}

/*
 * Process a received Ethernet packet; the packet is in the
 * mbuf chain m with the ethernet header at the front.
 */
static void
ether_input_internal(struct ifnet *ifp, struct mbuf *m)
{
        struct ether_header *eh;
        u_short etype;

        if ((ifp->if_flags & IFF_UP) == 0) {
                m_freem(m);
                return;
        }
#ifdef DIAGNOSTIC
        if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
                if_printf(ifp, "discard frame at !IFF_DRV_RUNNING\n");
                m_freem(m);
                return;
        }
#endif
        if (__predict_false(m->m_len < ETHER_HDR_LEN)) {
                /* Drivers should pullup and ensure the mbuf is valid */
                if_printf(ifp, "discard frame w/o leading ethernet "
                                "header (len %d pkt len %d)\n",
                                m->m_len, m->m_pkthdr.len);
                if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
                m_freem(m);
                return;
        }
        eh = mtod(m, struct ether_header *);
        etype = ntohs(eh->ether_type);
        random_harvest_queue_ether(m, sizeof(*m));

#ifdef EXPERIMENTAL
#if defined(INET6) && defined(INET)
        /* draft-ietf-6man-ipv6only-flag */
        /* Catch ETHERTYPE_IP, and ETHERTYPE_[REV]ARP if we are v6-only. */
        if ((ifp->if_inet6->nd_flags & ND6_IFF_IPV6_ONLY_MASK) != 0) {
                switch (etype) {
                case ETHERTYPE_IP:
                case ETHERTYPE_ARP:
                case ETHERTYPE_REVARP:
                        m_freem(m);
                        return;
                        /* NOTREACHED */
                        break;
                };
        }
#endif
#endif

        CURVNET_SET_QUIET(ifp->if_vnet);

        if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
                if (ETHER_IS_BROADCAST(eh->ether_dhost))
                        m->m_flags |= M_BCAST;
                else
                        m->m_flags |= M_MCAST;
                if_inc_counter(ifp, IFCOUNTER_IMCASTS, 1);
        }

#ifdef MAC
        /*
         * Tag the mbuf with an appropriate MAC label before any other
         * consumers can get to it.
         */
        mac_ifnet_create_mbuf(ifp, m);
#endif

        /*
         * Give bpf a chance at the packet.
         */
        ETHER_BPF_MTAP(ifp, m);

        if (!(ifp->if_capenable & IFCAP_HWSTATS))
                if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);

        /* Allow monitor mode to claim this frame, after stats are updated. */
        if (ifp->if_flags & IFF_MONITOR) {
                m_freem(m);
                CURVNET_RESTORE();
                return;
        }

        /* Handle input from a lagg(4) port */
        if (ifp->if_type == IFT_IEEE8023ADLAG) {
                KASSERT(lagg_input_ethernet_p != NULL,
                    ("%s: if_lagg not loaded!", __func__));
                m = (*lagg_input_ethernet_p)(ifp, m);
                if (m != NULL)
                        ifp = m->m_pkthdr.rcvif;
                else {
                        CURVNET_RESTORE();
                        return;
                }
        }

        /*
         * If the hardware did not process an 802.1Q tag, do this now,
         * to allow 802.1P priority frames to be passed to the main input
         * path correctly.
         */
        if ((m->m_flags & M_VLANTAG) == 0 &&
            ((etype == ETHERTYPE_VLAN) || (etype == ETHERTYPE_QINQ))) {
                struct ether_vlan_header *evl;

                if (m->m_len < sizeof(*evl) &&
                    (m = m_pullup(m, sizeof(*evl))) == NULL) {
#ifdef DIAGNOSTIC
                        if_printf(ifp, "cannot pullup VLAN header\n");
#endif
                        if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
                        CURVNET_RESTORE();
                        return;
                }

                evl = mtod(m, struct ether_vlan_header *);
                m->m_pkthdr.ether_vtag = ntohs(evl->evl_tag);
                m->m_flags |= M_VLANTAG;

                bcopy((char *)evl, (char *)evl + ETHER_VLAN_ENCAP_LEN,
                    ETHER_HDR_LEN - ETHER_TYPE_LEN);
                m_adj(m, ETHER_VLAN_ENCAP_LEN);
                eh = mtod(m, struct ether_header *);
        }

        M_SETFIB(m, ifp->if_fib);

        /* Allow ng_ether(4) to claim this frame. */
        if (ifp->if_l2com != NULL) {
                KASSERT(ng_ether_input_p != NULL,
                    ("%s: ng_ether_input_p is NULL", __func__));
                m->m_flags &= ~M_PROMISC;
                (*ng_ether_input_p)(ifp, &m);
                if (m == NULL) {
                        CURVNET_RESTORE();
                        return;
                }
                eh = mtod(m, struct ether_header *);
        }

        /*
         * Allow if_bridge(4) to claim this frame.
         *
         * The BRIDGE_INPUT() macro will update ifp if the bridge changed it
         * and the frame should be delivered locally.
         *
         * If M_BRIDGE_INJECT is set, the packet was received directly by the
         * bridge via netmap, so "ifp" is the bridge itself and the packet
         * should be re-examined.
         */
        if (ifp->if_bridge != NULL || (m->m_flags & M_BRIDGE_INJECT) != 0) {
                m->m_flags &= ~M_PROMISC;
                BRIDGE_INPUT(ifp, m);
                if (m == NULL) {
                        CURVNET_RESTORE();
                        return;
                }
                eh = mtod(m, struct ether_header *);
        }

#if defined(INET) || defined(INET6)
        /*
         * Clear M_PROMISC on frame so that carp(4) will see it when the
         * mbuf flows up to Layer 3.
         * FreeBSD's implementation of carp(4) uses the inprotosw
         * to dispatch IPPROTO_CARP. carp(4) also allocates its own
         * Ethernet addresses of the form 00:00:5e:00:01:xx, which
         * is outside the scope of the M_PROMISC test below.
         * TODO: Maintain a hash table of ethernet addresses other than
         * ether_dhost which may be active on this ifp.
         */
        if (ifp->if_carp && (*carp_forus_p)(ifp, eh->ether_dhost)) {
                m->m_flags &= ~M_PROMISC;
        } else
#endif
        {
                /*
                 * If the frame received was not for our MAC address, set the
                 * M_PROMISC flag on the mbuf chain. The frame may need to
                 * be seen by the rest of the Ethernet input path in case of
                 * re-entry (e.g. bridge, vlan, netgraph) but should not be
                 * seen by upper protocol layers.
                 */
                if (!ETHER_IS_MULTICAST(eh->ether_dhost) &&
                    memcmp(IF_LLADDR(ifp), eh->ether_dhost, ETHER_ADDR_LEN) != 0)
                        m->m_flags |= M_PROMISC;
        }

        ether_demux(ifp, m);
        CURVNET_RESTORE();
}

/*
 * Ethernet input dispatch; by default, direct dispatch here regardless of
 * global configuration.  However, if RSS is enabled, hook up RSS affinity
 * so that when deferred or hybrid dispatch is enabled, we can redistribute
 * load based on RSS.
 *
 * XXXRW: Would be nice if the ifnet passed up a flag indicating whether or
 * not it had already done work distribution via multi-queue.  Then we could
 * direct dispatch in the event load balancing was already complete and
 * handle the case of interfaces with different capabilities better.
 *
 * XXXRW: Sort of want an M_DISTRIBUTED flag to avoid multiple distributions
 * at multiple layers?
 *
 * XXXRW: For now, enable all this only if RSS is compiled in, although it
 * works fine without RSS.  Need to characterise the performance overhead
 * of the detour through the netisr code in the event the result is always
 * direct dispatch.
 */
static void
ether_nh_input(struct mbuf *m)
{

        M_ASSERTPKTHDR(m);
        KASSERT(m->m_pkthdr.rcvif != NULL,
            ("%s: NULL interface pointer", __func__));
        ether_input_internal(m->m_pkthdr.rcvif, m);
}

static struct netisr_handler    ether_nh = {
        .nh_name = "ether",
        .nh_handler = ether_nh_input,
        .nh_proto = NETISR_ETHER,
#ifdef RSS
        .nh_policy = NETISR_POLICY_CPU,
        .nh_dispatch = NETISR_DISPATCH_DIRECT,
        .nh_m2cpuid = rss_m2cpuid,
#else
        .nh_policy = NETISR_POLICY_SOURCE,
        .nh_dispatch = NETISR_DISPATCH_DIRECT,
#endif
};

static void
ether_init(__unused void *arg)
{

        netisr_register(&ether_nh);
}
SYSINIT(ether, SI_SUB_INIT_IF, SI_ORDER_ANY, ether_init, NULL);

static void
vnet_ether_init(const __unused void *arg)
{
        struct pfil_head_args args;

        args.pa_version = PFIL_VERSION;
        args.pa_flags = PFIL_IN | PFIL_OUT;
        args.pa_type = PFIL_TYPE_ETHERNET;
        args.pa_headname = PFIL_ETHER_NAME;
        V_link_pfil_head = pfil_head_register(&args);

#ifdef VIMAGE
        netisr_register_vnet(&ether_nh);
#endif
}
VNET_SYSINIT(vnet_ether_init, SI_SUB_PROTO_IF, SI_ORDER_ANY,
    vnet_ether_init, NULL);

#ifdef VIMAGE
static void
vnet_ether_pfil_destroy(const __unused void *arg)
{

        pfil_head_unregister(V_link_pfil_head);
}
VNET_SYSUNINIT(vnet_ether_pfil_uninit, SI_SUB_PROTO_PFIL, SI_ORDER_ANY,
    vnet_ether_pfil_destroy, NULL);

static void
vnet_ether_destroy(__unused void *arg)
{

        netisr_unregister_vnet(&ether_nh);
}
VNET_SYSUNINIT(vnet_ether_uninit, SI_SUB_PROTO_IF, SI_ORDER_ANY,
    vnet_ether_destroy, NULL);
#endif

static void
ether_input(struct ifnet *ifp, struct mbuf *m)
{
        struct epoch_tracker et;
        struct mbuf *mn;
        bool needs_epoch;

        needs_epoch = (ifp->if_flags & IFF_NEEDSEPOCH);
#ifdef INVARIANTS
        /*
         * This temporary code is here to prevent epoch unaware and unmarked
         * drivers to panic the system.  Once all drivers are taken care of,
         * the whole INVARIANTS block should go away.
         */
        if (!needs_epoch && !in_epoch(net_epoch_preempt)) {
                static bool printedonce;

                needs_epoch = true;
                if (!printedonce) {
                        printedonce = true;
                        if_printf(ifp, "called %s w/o net epoch! "
                            "PLEASE file a bug report.", __func__);
#ifdef KDB
                        kdb_backtrace();
#endif
                }
        }
#endif

        /*
         * The drivers are allowed to pass in a chain of packets linked with
         * m_nextpkt. We split them up into separate packets here and pass
         * them up. This allows the drivers to amortize the receive lock.
         */
        CURVNET_SET_QUIET(ifp->if_vnet);
        if (__predict_false(needs_epoch))
                NET_EPOCH_ENTER(et);
        while (m) {
                mn = m->m_nextpkt;
                m->m_nextpkt = NULL;

                /*
                 * We will rely on rcvif being set properly in the deferred
                 * context, so assert it is correct here.
                 */
                MPASS((m->m_pkthdr.csum_flags & CSUM_SND_TAG) == 0);
                KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch m %p "
                    "rcvif %p ifp %p", __func__, m, m->m_pkthdr.rcvif, ifp));
                netisr_dispatch(NETISR_ETHER, m);
                m = mn;
        }
        if (__predict_false(needs_epoch))
                NET_EPOCH_EXIT(et);
        CURVNET_RESTORE();
}

/*
 * Upper layer processing for a received Ethernet packet.
 */
void
ether_demux(struct ifnet *ifp, struct mbuf *m)
{
        struct ether_header *eh;
        int i, isr;
        u_short ether_type;

        NET_EPOCH_ASSERT();
        KASSERT(ifp != NULL, ("%s: NULL interface pointer", __func__));

        /* Do not grab PROMISC frames in case we are re-entered. */
        if (PFIL_HOOKED_IN(V_link_pfil_head) && !(m->m_flags & M_PROMISC)) {
                i = pfil_mbuf_in(V_link_pfil_head, &m, ifp, NULL);
                if (i != PFIL_PASS)
                        return;
        }

        eh = mtod(m, struct ether_header *);
        ether_type = ntohs(eh->ether_type);

        /*
         * If this frame has a VLAN tag other than 0, call vlan_input()
         * if its module is loaded. Otherwise, drop.
         */
        if ((m->m_flags & M_VLANTAG) &&
            EVL_VLANOFTAG(m->m_pkthdr.ether_vtag) != 0) {
                if (ifp->if_vlantrunk == NULL) {
                        if_inc_counter(ifp, IFCOUNTER_NOPROTO, 1);
                        m_freem(m);
                        return;
                }
                KASSERT(vlan_input_p != NULL,("%s: VLAN not loaded!",
                    __func__));
                /* Clear before possibly re-entering ether_input(). */
                m->m_flags &= ~M_PROMISC;
                (*vlan_input_p)(ifp, m);
                return;
        }

        /*
         * Pass promiscuously received frames to the upper layer if the user
         * requested this by setting IFF_PPROMISC. Otherwise, drop them.
         */
        if ((ifp->if_flags & IFF_PPROMISC) == 0 && (m->m_flags & M_PROMISC)) {
                m_freem(m);
                return;
        }

        /*
         * Reset layer specific mbuf flags to avoid confusing upper layers.
         */
        m->m_flags &= ~M_VLANTAG;
        m_clrprotoflags(m);

        /*
         * Dispatch frame to upper layer.
         */
        switch (ether_type) {
#ifdef INET
        case ETHERTYPE_IP:
                isr = NETISR_IP;
                break;

        case ETHERTYPE_ARP:
                if (ifp->if_flags & IFF_NOARP) {
                        /* Discard packet if ARP is disabled on interface */
                        m_freem(m);
                        return;
                }
                isr = NETISR_ARP;
                break;
#endif
#ifdef INET6
        case ETHERTYPE_IPV6:
                isr = NETISR_IPV6;
                break;
#endif
        default:
                goto discard;
        }

        /* Strip off Ethernet header. */
        m_adj(m, ETHER_HDR_LEN);

        netisr_dispatch(isr, m);
        return;

discard:
        /*
         * Packet is to be discarded.  If netgraph is present,
         * hand the packet to it for last chance processing;
         * otherwise dispose of it.
         */
        if (ifp->if_l2com != NULL) {
                KASSERT(ng_ether_input_orphan_p != NULL,
                    ("ng_ether_input_orphan_p is NULL"));
                (*ng_ether_input_orphan_p)(ifp, m);
                return;
        }
        m_freem(m);
}

/*
 * Convert Ethernet address to printable (loggable) representation.
 * This routine is for compatibility; it's better to just use
 *
 *      printf("%6D", <pointer to address>, ":");
 *
 * since there's no static buffer involved.
 */
char *
ether_sprintf(const u_char *ap)
{
        static char etherbuf[18];
        snprintf(etherbuf, sizeof (etherbuf), "%6D", ap, ":");
        return (etherbuf);
}

/*
 * Perform common duties while attaching to interface list
 */
void
ether_ifattach(struct ifnet *ifp, const u_int8_t *lla)
{
        int i;
        struct ifaddr *ifa;
        struct sockaddr_dl *sdl;

        ifp->if_addrlen = ETHER_ADDR_LEN;
        ifp->if_hdrlen = (ifp->if_capabilities & IFCAP_VLAN_MTU) != 0 ?
            ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN : ETHER_HDR_LEN;
        ifp->if_mtu = ETHERMTU;
        if_attach(ifp);
        ifp->if_output = ether_output;
        ifp->if_input = ether_input;
        ifp->if_resolvemulti = ether_resolvemulti;
        ifp->if_requestencap = ether_requestencap;
        if (ifp->if_baudrate == 0)
                ifp->if_baudrate = IF_Mbps(10);         /* just a default */
        ifp->if_broadcastaddr = etherbroadcastaddr;

        ifa = ifp->if_addr;
        KASSERT(ifa != NULL, ("%s: no lladdr!\n", __func__));
        sdl = (struct sockaddr_dl *)ifa->ifa_addr;
        sdl->sdl_type = IFT_ETHER;
        sdl->sdl_alen = ifp->if_addrlen;
        bcopy(lla, LLADDR(sdl), ifp->if_addrlen);

        if (ifp->if_hw_addr != NULL)
                bcopy(lla, ifp->if_hw_addr, ifp->if_addrlen);

        bpfattach(ifp, DLT_EN10MB, ETHER_HDR_LEN);

        /* Announce Ethernet MAC address if non-zero. */
        for (i = 0; i < ifp->if_addrlen; i++)
                if (lla[i] != 0)
                        break; 
        if (i != ifp->if_addrlen)
                if_printf(ifp, "Ethernet address: %6D\n", lla, ":");

        uuid_ether_add(LLADDR(sdl));

        /* Add necessary bits are setup; announce it now. */
        EVENTHANDLER_INVOKE(ether_ifattach_event, ifp);
        if (IS_DEFAULT_VNET(curvnet))
                devctl_notify("ETHERNET", ifp->if_xname, "IFATTACH", NULL);
}

/*
 * Perform common duties while detaching an Ethernet interface
 */
void
ether_ifdetach(struct ifnet *ifp)
{
        struct sockaddr_dl *sdl;

        sdl = (struct sockaddr_dl *)(ifp->if_addr->ifa_addr);
        uuid_ether_del(LLADDR(sdl));

        bpfdetach(ifp);
        if_detach(ifp);
}

SYSCTL_DECL(_net_link);
SYSCTL_NODE(_net_link, IFT_ETHER, ether, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Ethernet");

#if 0
/*
 * This is for reference.  We have a table-driven version
 * of the little-endian crc32 generator, which is faster
 * than the double-loop.
 */
uint32_t
ether_crc32_le(const uint8_t *buf, size_t len)
{
        size_t i;
        uint32_t crc;
        int bit;
        uint8_t data;

        crc = 0xffffffff;       /* initial value */

        for (i = 0; i < len; i++) {
                for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1) {
                        carry = (crc ^ data) & 1;
                        crc >>= 1;
                        if (carry)
                                crc = (crc ^ ETHER_CRC_POLY_LE);
                }
        }

        return (crc);
}
#else
uint32_t
ether_crc32_le(const uint8_t *buf, size_t len)
{
        static const uint32_t crctab[] = {
                0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
                0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
                0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
                0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
        };
        size_t i;
        uint32_t crc;

        crc = 0xffffffff;       /* initial value */

        for (i = 0; i < len; i++) {
                crc ^= buf[i];
                crc = (crc >> 4) ^ crctab[crc & 0xf];
                crc = (crc >> 4) ^ crctab[crc & 0xf];
        }

        return (crc);
}
#endif

uint32_t
ether_crc32_be(const uint8_t *buf, size_t len)
{
        size_t i;
        uint32_t crc, carry;
        int bit;
        uint8_t data;

        crc = 0xffffffff;       /* initial value */

        for (i = 0; i < len; i++) {
                for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1) {
                        carry = ((crc & 0x80000000) ? 1 : 0) ^ (data & 0x01);
                        crc <<= 1;
                        if (carry)
                                crc = (crc ^ ETHER_CRC_POLY_BE) | carry;
                }
        }

        return (crc);
}

int
ether_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
{
        struct ifaddr *ifa = (struct ifaddr *) data;
        struct ifreq *ifr = (struct ifreq *) data;
        int error = 0;

        switch (command) {
        case SIOCSIFADDR:
                ifp->if_flags |= IFF_UP;

                switch (ifa->ifa_addr->sa_family) {
#ifdef INET
                case AF_INET:
                        ifp->if_init(ifp->if_softc);    /* before arpwhohas */
                        arp_ifinit(ifp, ifa);
                        break;
#endif
                default:
                        ifp->if_init(ifp->if_softc);
                        break;
                }
                break;

        case SIOCGIFADDR:
                bcopy(IF_LLADDR(ifp), &ifr->ifr_addr.sa_data[0],
                    ETHER_ADDR_LEN);
                break;

        case SIOCSIFMTU:
                /*
                 * Set the interface MTU.
                 */
                if (ifr->ifr_mtu > ETHERMTU) {
                        error = EINVAL;
                } else {
                        ifp->if_mtu = ifr->ifr_mtu;
                }
                break;

        case SIOCSLANPCP:
                error = priv_check(curthread, PRIV_NET_SETLANPCP);
                if (error != 0)
                        break;
                if (ifr->ifr_lan_pcp > 7 &&
                    ifr->ifr_lan_pcp != IFNET_PCP_NONE) {
                        error = EINVAL;
                } else {
                        ifp->if_pcp = ifr->ifr_lan_pcp;
                        /* broadcast event about PCP change */
                        EVENTHANDLER_INVOKE(ifnet_event, ifp, IFNET_EVENT_PCP);
                }
                break;

        case SIOCGLANPCP:
                ifr->ifr_lan_pcp = ifp->if_pcp;
                break;

        default:
                error = EINVAL;                 /* XXX netbsd has ENOTTY??? */
                break;
        }
        return (error);
}

static int
ether_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
        struct sockaddr *sa)
{
        struct sockaddr_dl *sdl;
#ifdef INET
        struct sockaddr_in *sin;
#endif
#ifdef INET6
        struct sockaddr_in6 *sin6;
#endif
        u_char *e_addr;

        switch(sa->sa_family) {
        case AF_LINK:
                /*
                 * No mapping needed. Just check that it's a valid MC address.
                 */
                sdl = (struct sockaddr_dl *)sa;
                e_addr = LLADDR(sdl);
                if (!ETHER_IS_MULTICAST(e_addr))
                        return EADDRNOTAVAIL;
                *llsa = NULL;
                return 0;

#ifdef INET
        case AF_INET:
                sin = (struct sockaddr_in *)sa;
                if (!IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
                        return EADDRNOTAVAIL;
                sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
                sdl->sdl_alen = ETHER_ADDR_LEN;
                e_addr = LLADDR(sdl);
                ETHER_MAP_IP_MULTICAST(&sin->sin_addr, e_addr);
                *llsa = (struct sockaddr *)sdl;
                return 0;
#endif
#ifdef INET6
        case AF_INET6:
                sin6 = (struct sockaddr_in6 *)sa;
                if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
                        /*
                         * An IP6 address of 0 means listen to all
                         * of the Ethernet multicast address used for IP6.
                         * (This is used for multicast routers.)
                         */
                        ifp->if_flags |= IFF_ALLMULTI;
                        *llsa = NULL;
                        return 0;
                }
                if (!IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
                        return EADDRNOTAVAIL;
                sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
                sdl->sdl_alen = ETHER_ADDR_LEN;
                e_addr = LLADDR(sdl);
                ETHER_MAP_IPV6_MULTICAST(&sin6->sin6_addr, e_addr);
                *llsa = (struct sockaddr *)sdl;
                return 0;
#endif

        default:
                /*
                 * Well, the text isn't quite right, but it's the name
                 * that counts...
                 */
                return EAFNOSUPPORT;
        }
}

static moduledata_t ether_mod = {
        .name = "ether",
};

void
ether_vlan_mtap(struct bpf_if *bp, struct mbuf *m, void *data, u_int dlen)
{
        struct ether_vlan_header vlan;
        struct mbuf mv, mb;

        KASSERT((m->m_flags & M_VLANTAG) != 0,
            ("%s: vlan information not present", __func__));
        KASSERT(m->m_len >= sizeof(struct ether_header),
            ("%s: mbuf not large enough for header", __func__));
        bcopy(mtod(m, char *), &vlan, sizeof(struct ether_header));
        vlan.evl_proto = vlan.evl_encap_proto;
        vlan.evl_encap_proto = htons(ETHERTYPE_VLAN);
        vlan.evl_tag = htons(m->m_pkthdr.ether_vtag);
        m->m_len -= sizeof(struct ether_header);
        m->m_data += sizeof(struct ether_header);
        /*
         * If a data link has been supplied by the caller, then we will need to
         * re-create a stack allocated mbuf chain with the following structure:
         *
         * (1) mbuf #1 will contain the supplied data link
         * (2) mbuf #2 will contain the vlan header
         * (3) mbuf #3 will contain the original mbuf's packet data
         *
         * Otherwise, submit the packet and vlan header via bpf_mtap2().
         */
        if (data != NULL) {
                mv.m_next = m;
                mv.m_data = (caddr_t)&vlan;
                mv.m_len = sizeof(vlan);
                mb.m_next = &mv;
                mb.m_data = data;
                mb.m_len = dlen;
                bpf_mtap(bp, &mb);
        } else
                bpf_mtap2(bp, &vlan, sizeof(vlan), m);
        m->m_len += sizeof(struct ether_header);
        m->m_data -= sizeof(struct ether_header);
}

struct mbuf *
ether_vlanencap_proto(struct mbuf *m, uint16_t tag, uint16_t proto)
{
        struct ether_vlan_header *evl;

        M_PREPEND(m, ETHER_VLAN_ENCAP_LEN, M_NOWAIT);
        if (m == NULL)
                return (NULL);
        /* M_PREPEND takes care of m_len, m_pkthdr.len for us */

        if (m->m_len < sizeof(*evl)) {
                m = m_pullup(m, sizeof(*evl));
                if (m == NULL)
                        return (NULL);
        }

        /*
         * Transform the Ethernet header into an Ethernet header
         * with 802.1Q encapsulation.
         */
        evl = mtod(m, struct ether_vlan_header *);
        bcopy((char *)evl + ETHER_VLAN_ENCAP_LEN,
            (char *)evl, ETHER_HDR_LEN - ETHER_TYPE_LEN);
        evl->evl_encap_proto = htons(proto);
        evl->evl_tag = htons(tag);
        return (m);
}

void
ether_bpf_mtap_if(struct ifnet *ifp, struct mbuf *m)
{
        if (bpf_peers_present(ifp->if_bpf)) {
                M_ASSERTVALID(m);
                if ((m->m_flags & M_VLANTAG) != 0)
                        ether_vlan_mtap(ifp->if_bpf, m, NULL, 0);
                else
                        bpf_mtap(ifp->if_bpf, m);
        }
}

static SYSCTL_NODE(_net_link, IFT_L2VLAN, vlan, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "IEEE 802.1Q VLAN");
static SYSCTL_NODE(_net_link_vlan, PF_LINK, link,
    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "for consistency");

VNET_DEFINE_STATIC(int, soft_pad);
#define V_soft_pad      VNET(soft_pad)
SYSCTL_INT(_net_link_vlan, OID_AUTO, soft_pad, CTLFLAG_RW | CTLFLAG_VNET,
    &VNET_NAME(soft_pad), 0,
    "pad short frames before tagging");

/*
 * For now, make preserving PCP via an mbuf tag optional, as it increases
 * per-packet memory allocations and frees.  In the future, it would be
 * preferable to reuse ether_vtag for this, or similar.
 */
VNET_DEFINE(int, vlan_mtag_pcp) = 0;
#define V_vlan_mtag_pcp VNET(vlan_mtag_pcp)
SYSCTL_INT(_net_link_vlan, OID_AUTO, mtag_pcp, CTLFLAG_RW | CTLFLAG_VNET,
    &VNET_NAME(vlan_mtag_pcp), 0,
    "Retain VLAN PCP information as packets are passed up the stack");

static inline bool
ether_do_pcp(struct ifnet *ifp, struct mbuf *m)
{
        if (ifp->if_type == IFT_L2VLAN)
                return (false);
        if (ifp->if_pcp != IFNET_PCP_NONE || (m->m_flags & M_VLANTAG) != 0)
                return (true);
        if (V_vlan_mtag_pcp &&
            m_tag_locate(m, MTAG_8021Q, MTAG_8021Q_PCP_OUT, NULL) != NULL)
                return (true);
        return (false);
}

bool
ether_8021q_frame(struct mbuf **mp, struct ifnet *ife, struct ifnet *p,
    const struct ether_8021q_tag *qtag)
{
        struct m_tag *mtag;
        int n;
        uint16_t tag;
        uint8_t pcp = qtag->pcp;
        static const char pad[8];       /* just zeros */

        /*
         * Pad the frame to the minimum size allowed if told to.
         * This option is in accord with IEEE Std 802.1Q, 2003 Ed.,
         * paragraph C.4.4.3.b.  It can help to work around buggy
         * bridges that violate paragraph C.4.4.3.a from the same
         * document, i.e., fail to pad short frames after untagging.
         * E.g., a tagged frame 66 bytes long (incl. FCS) is OK, but
         * untagging it will produce a 62-byte frame, which is a runt
         * and requires padding.  There are VLAN-enabled network
         * devices that just discard such runts instead or mishandle
         * them somehow.
         */
        if (V_soft_pad && p->if_type == IFT_ETHER) {
                for (n = ETHERMIN + ETHER_HDR_LEN - (*mp)->m_pkthdr.len;
                     n > 0; n -= sizeof(pad)) {
                        if (!m_append(*mp, min(n, sizeof(pad)), pad))
                                break;
                }
                if (n > 0) {
                        m_freem(*mp);
                        *mp = NULL;
                        if_printf(ife, "cannot pad short frame");
                        return (false);
                }
        }

        /*
         * If PCP is set in mbuf, use it
         */
        if ((*mp)->m_flags & M_VLANTAG) {
                pcp = EVL_PRIOFTAG((*mp)->m_pkthdr.ether_vtag);
        }

        /*
         * If underlying interface can do VLAN tag insertion itself,
         * just pass the packet along. However, we need some way to
         * tell the interface where the packet came from so that it
         * knows how to find the VLAN tag to use, so we attach a
         * packet tag that holds it.
         */
        if (V_vlan_mtag_pcp && (mtag = m_tag_locate(*mp, MTAG_8021Q,
            MTAG_8021Q_PCP_OUT, NULL)) != NULL)
                tag = EVL_MAKETAG(qtag->vid, *(uint8_t *)(mtag + 1), 0);
        else
                tag = EVL_MAKETAG(qtag->vid, pcp, 0);
        if ((p->if_capenable & IFCAP_VLAN_HWTAGGING) &&
            (qtag->proto == ETHERTYPE_VLAN)) {
                (*mp)->m_pkthdr.ether_vtag = tag;
                (*mp)->m_flags |= M_VLANTAG;
        } else {
                *mp = ether_vlanencap_proto(*mp, tag, qtag->proto);
                if (*mp == NULL) {
                        if_printf(ife, "unable to prepend 802.1Q header");
                        return (false);
                }
                (*mp)->m_flags &= ~M_VLANTAG;
        }
        return (true);
}

/*
 * Allocate an address from the FreeBSD Foundation OUI.  This uses a
 * cryptographic hash function on the containing jail's name, UUID and the
 * interface name to attempt to provide a unique but stable address.
 * Pseudo-interfaces which require a MAC address should use this function to
 * allocate non-locally-administered addresses.
 */
void
ether_gen_addr_byname(const char *nameunit, struct ether_addr *hwaddr)
{
        SHA1_CTX ctx;
        char *buf;
        char uuid[HOSTUUIDLEN + 1];
        uint64_t addr;
        int i, sz;
        unsigned char digest[SHA1_RESULTLEN];
        char jailname[MAXHOSTNAMELEN];

        getcredhostuuid(curthread->td_ucred, uuid, sizeof(uuid));
        if (strncmp(uuid, DEFAULT_HOSTUUID, sizeof(uuid)) == 0) {
                /* Fall back to a random mac address. */
                goto rando;
        }

        /* If each (vnet) jail would also have a unique hostuuid this would not
         * be necessary. */
        getjailname(curthread->td_ucred, jailname, sizeof(jailname));
        sz = asprintf(&buf, M_TEMP, "%s-%s-%s", uuid, nameunit,
            jailname);
        if (sz < 0) {
                /* Fall back to a random mac address. */
                goto rando;
        }

        SHA1Init(&ctx);
        SHA1Update(&ctx, buf, sz);
        SHA1Final(digest, &ctx);
        free(buf, M_TEMP);

        addr = (digest[0] << 8) | digest[1] | OUI_FREEBSD_GENERATED_LOW;
        for (i = 0; i < ETHER_ADDR_LEN; ++i) {
                hwaddr->octet[i] = addr >> ((ETHER_ADDR_LEN - i - 1) * 8) &
                    0xFF;
        }

        return;
rando:
        arc4rand(hwaddr, sizeof(*hwaddr), 0);
        /* Unicast */
        hwaddr->octet[0] &= 0xFE;
        /* Locally administered. */
        hwaddr->octet[0] |= 0x02;
}

void
ether_gen_addr(struct ifnet *ifp, struct ether_addr *hwaddr)
{
        ether_gen_addr_byname(if_name(ifp), hwaddr);
}

DECLARE_MODULE(ether, ether_mod, SI_SUB_INIT_IF, SI_ORDER_ANY);
MODULE_VERSION(ether, 1);