ng_iface.c

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/*
 * ng_iface.c
 */
 
/*-
 * Copyright (c) 1996-1999 Whistle Communications, Inc.
 * All rights reserved.
 * 
 * Subject to the following obligations and disclaimer of warranty, use and
 * redistribution of this software, in source or object code forms, with or
 * without modifications are expressly permitted by Whistle Communications;
 * provided, however, that:
 * 1. Any and all reproductions of the source or object code must include the
 *    copyright notice above and the following disclaimer of warranties; and
 * 2. No rights are granted, in any manner or form, to use Whistle
 *    Communications, Inc. trademarks, including the mark "WHISTLE
 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
 *    such appears in the above copyright notice or in the software.
 * 
 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * Author: Archie Cobbs <archie@freebsd.org>
 *
 * $FreeBSD$
 * $Whistle: ng_iface.c,v 1.33 1999/11/01 09:24:51 julian Exp $
 */
 
/*
 * This node is also a system networking interface. It has
 * a hook for each protocol (IP, AppleTalk, etc). Packets
 * are simply relayed between the interface and the hooks.
 *
 * Interfaces are named ng0, ng1, etc.  New nodes take the
 * first available interface name.
 *
 * This node also includes Berkeley packet filter support.
 */
 
#include "opt_inet.h"
#include "opt_inet6.h"
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/random.h>
#include <sys/rmlock.h>
#include <sys/sockio.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/libkern.h>
 
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_types.h>
#include <net/bpf.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/vnet.h>
 
#include <netinet/in.h>
 
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_iface.h>
 
#ifdef NG_SEPARATE_MALLOC
static MALLOC_DEFINE(M_NETGRAPH_IFACE, "netgraph_iface", "netgraph iface node");
#else
#define M_NETGRAPH_IFACE M_NETGRAPH
#endif
 
static SYSCTL_NODE(_net_graph, OID_AUTO, iface, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Point to point netgraph interface");
VNET_DEFINE_STATIC(int, ng_iface_max_nest) = 2;
#define V_ng_iface_max_nest     VNET(ng_iface_max_nest)
SYSCTL_INT(_net_graph_iface, OID_AUTO, max_nesting, CTLFLAG_VNET | CTLFLAG_RW,
    &VNET_NAME(ng_iface_max_nest), 0, "Max nested tunnels");
 
/* This struct describes one address family */
struct iffam {
        sa_family_t     family;         /* Address family */
        const char      *hookname;      /* Name for hook */
};
typedef const struct iffam *iffam_p;
 
/* List of address families supported by our interface */
const static struct iffam gFamilies[] = {
        { AF_INET,      NG_IFACE_HOOK_INET      },
        { AF_INET6,     NG_IFACE_HOOK_INET6     },
};
#define NUM_FAMILIES            nitems(gFamilies)
 
/* Node private data */
struct ng_iface_private {
        struct  ifnet *ifp;             /* Our interface */
        int     unit;                   /* Interface unit number */
        node_p  node;                   /* Our netgraph node */
        hook_p  hooks[NUM_FAMILIES];    /* Hook for each address family */
        struct rmlock   lock;           /* Protect private data changes */
};
typedef struct ng_iface_private *priv_p;
 
#define PRIV_RLOCK(priv, t)     rm_rlock(&priv->lock, t)
#define PRIV_RUNLOCK(priv, t)   rm_runlock(&priv->lock, t)
#define PRIV_WLOCK(priv)        rm_wlock(&priv->lock)
#define PRIV_WUNLOCK(priv)      rm_wunlock(&priv->lock)
 
/* Interface methods */
static void     ng_iface_start(struct ifnet *ifp);
static int      ng_iface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
static int      ng_iface_output(struct ifnet *ifp, struct mbuf *m0,
                        const struct sockaddr *dst, struct route *ro);
static void     ng_iface_bpftap(struct ifnet *ifp,
                        struct mbuf *m, sa_family_t family);
static int      ng_iface_send(struct ifnet *ifp, struct mbuf *m,
                        sa_family_t sa);
#ifdef DEBUG
static void     ng_iface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
#endif
 
/* Netgraph methods */
static int              ng_iface_mod_event(module_t, int, void *);
static ng_constructor_t ng_iface_constructor;
static ng_rcvmsg_t      ng_iface_rcvmsg;
static ng_shutdown_t    ng_iface_shutdown;
static ng_newhook_t     ng_iface_newhook;
static ng_rcvdata_t     ng_iface_rcvdata;
static ng_disconnect_t  ng_iface_disconnect;
 
/* Helper stuff */
static iffam_p  get_iffam_from_af(sa_family_t family);
static iffam_p  get_iffam_from_hook(priv_p priv, hook_p hook);
static iffam_p  get_iffam_from_name(const char *name);
static hook_p  *get_hook_from_iffam(priv_p priv, iffam_p iffam);
 
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_iface_cmds[] = {
        {
          NGM_IFACE_COOKIE,
          NGM_IFACE_GET_IFNAME,
          "getifname",
          NULL,
          &ng_parse_string_type
        },
        {
          NGM_IFACE_COOKIE,
          NGM_IFACE_POINT2POINT,
          "point2point",
          NULL,
          NULL
        },
        {
          NGM_IFACE_COOKIE,
          NGM_IFACE_BROADCAST,
          "broadcast",
          NULL,
          NULL
        },
        {
          NGM_IFACE_COOKIE,
          NGM_IFACE_GET_IFINDEX,
          "getifindex",
          NULL,
          &ng_parse_uint32_type
        },
        { 0 }
};
 
/* Node type descriptor */
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_IFACE_NODE_TYPE,
        .mod_event =    ng_iface_mod_event,
        .constructor =  ng_iface_constructor,
        .rcvmsg =       ng_iface_rcvmsg,
        .shutdown =     ng_iface_shutdown,
        .newhook =      ng_iface_newhook,
        .rcvdata =      ng_iface_rcvdata,
        .disconnect =   ng_iface_disconnect,
        .cmdlist =      ng_iface_cmds,
};
NETGRAPH_INIT(iface, &typestruct);
 
VNET_DEFINE_STATIC(struct unrhdr *, ng_iface_unit);
#define V_ng_iface_unit                 VNET(ng_iface_unit)
 
/************************************************************************
                        HELPER STUFF
 ************************************************************************/
 
/*
 * Get the family descriptor from the family ID
 */
static __inline iffam_p
get_iffam_from_af(sa_family_t family)
{
        iffam_p iffam;
        int k;
 
        for (k = 0; k < NUM_FAMILIES; k++) {
                iffam = &gFamilies[k];
                if (iffam->family == family)
                        return (iffam);
        }
        return (NULL);
}
 
/*
 * Get the family descriptor from the hook
 */
static __inline iffam_p
get_iffam_from_hook(priv_p priv, hook_p hook)
{
        int k;
 
        for (k = 0; k < NUM_FAMILIES; k++)
                if (priv->hooks[k] == hook)
                        return (&gFamilies[k]);
        return (NULL);
}
 
/*
 * Get the hook from the iffam descriptor
 */
 
static __inline hook_p *
get_hook_from_iffam(priv_p priv, iffam_p iffam)
{
        return (&priv->hooks[iffam - gFamilies]);
}
 
/*
 * Get the iffam descriptor from the name
 */
static __inline iffam_p
get_iffam_from_name(const char *name)
{
        iffam_p iffam;
        int k;
 
        for (k = 0; k < NUM_FAMILIES; k++) {
                iffam = &gFamilies[k];
                if (!strcmp(iffam->hookname, name))
                        return (iffam);
        }
        return (NULL);
}
 
/************************************************************************
                        INTERFACE STUFF
 ************************************************************************/
 
/*
 * Process an ioctl for the virtual interface
 */
static int
ng_iface_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
{
        struct ifreq *const ifr = (struct ifreq *) data;
        int error = 0;
 
#ifdef DEBUG
        ng_iface_print_ioctl(ifp, command, data);
#endif
        switch (command) {
        /* These two are mostly handled at a higher layer */
        case SIOCSIFADDR:
                ifp->if_flags |= IFF_UP;
                ifp->if_drv_flags |= IFF_DRV_RUNNING;
                ifp->if_drv_flags &= ~(IFF_DRV_OACTIVE);
                break;
        case SIOCGIFADDR:
                break;
 
        /* Set flags */
        case SIOCSIFFLAGS:
                /*
                 * If the interface is marked up and stopped, then start it.
                 * If it is marked down and running, then stop it.
                 */
                if (ifr->ifr_flags & IFF_UP) {
                        if (!(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
                                ifp->if_drv_flags &= ~(IFF_DRV_OACTIVE);
                                ifp->if_drv_flags |= IFF_DRV_RUNNING;
                        }
                } else {
                        if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                                ifp->if_drv_flags &= ~(IFF_DRV_RUNNING |
                                    IFF_DRV_OACTIVE);
                }
                break;
 
        /* Set the interface MTU */
        case SIOCSIFMTU:
                if (ifr->ifr_mtu > NG_IFACE_MTU_MAX
                    || ifr->ifr_mtu < NG_IFACE_MTU_MIN)
                        error = EINVAL;
                else
                        ifp->if_mtu = ifr->ifr_mtu;
                break;
 
        /* Stuff that's not supported */
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                error = 0;
                break;
        case SIOCSIFPHYS:
                error = EOPNOTSUPP;
                break;
 
        default:
                error = EINVAL;
                break;
        }
        return (error);
}
 
/*
 * This routine is called to deliver a packet out the interface.
 * We simply look at the address family and relay the packet to
 * the corresponding hook, if it exists and is connected.
 */
 
static int
ng_iface_output(struct ifnet *ifp, struct mbuf *m,
        const struct sockaddr *dst, struct route *ro)
{
        uint32_t af;
        int error;
 
        /* Check interface flags */
        if (!((ifp->if_flags & IFF_UP) &&
            (ifp->if_drv_flags & IFF_DRV_RUNNING))) {
                m_freem(m);
                return (ENETDOWN);
        }
 
        /* Protect from deadly infinite recursion. */
        error = if_tunnel_check_nesting(ifp, m, NGM_IFACE_COOKIE,
            V_ng_iface_max_nest);
        if (error) {
                m_freem(m);
                return (error);
        }
 
        /* BPF writes need to be handled specially. */
        if (dst->sa_family == AF_UNSPEC)
                bcopy(dst->sa_data, &af, sizeof(af));
        else
                af = RO_GET_FAMILY(ro, dst);
 
        /* Berkeley packet filter */
        ng_iface_bpftap(ifp, m, af);
 
        if (ALTQ_IS_ENABLED(&ifp->if_snd)) {
                M_PREPEND(m, sizeof(sa_family_t), M_NOWAIT);
                if (m == NULL) {
                        if_inc_counter(ifp, IFCOUNTER_OQDROPS, 1);
                        return (ENOBUFS);
                }
                *(sa_family_t *)m->m_data = af;
                error = (ifp->if_transmit)(ifp, m);
        } else
                error = ng_iface_send(ifp, m, af);
 
        return (error);
}
 
/*
 * Start method is used only when ALTQ is enabled.
 */
static void
ng_iface_start(struct ifnet *ifp)
{
        struct mbuf *m;
        sa_family_t sa;
 
        KASSERT(ALTQ_IS_ENABLED(&ifp->if_snd), ("%s without ALTQ", __func__));
 
        for(;;) {
                IFQ_DRV_DEQUEUE(&ifp->if_snd, m);
                if (m == NULL)
                        break;
                sa = *mtod(m, sa_family_t *);
                m_adj(m, sizeof(sa_family_t));
                ng_iface_send(ifp, m, sa);
        }
}
 
/*
 * Flash a packet by the BPF (requires prepending 4 byte AF header)
 * Note the phoney mbuf; this is OK because BPF treats it read-only.
 */
static void
ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
{
        KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));
        if (bpf_peers_present(ifp->if_bpf)) {
                int32_t family4 = (int32_t)family;
                bpf_mtap2(ifp->if_bpf, &family4, sizeof(family4), m);
        }
}
 
/*
 * This routine does actual delivery of the packet into the
 * netgraph(4). It is called from ng_iface_start() and
 * ng_iface_output().
 */
static int
ng_iface_send(struct ifnet *ifp, struct mbuf *m, sa_family_t sa)
{
        struct rm_priotracker priv_tracker;
        const priv_p priv = (priv_p) ifp->if_softc;
        const iffam_p iffam = get_iffam_from_af(sa);
        hook_p hook;
        int error;
        int len;
 
        /* Check address family to determine hook (if known) */
        if (iffam == NULL) {
                m_freem(m);
                log(LOG_WARNING, "%s: can't handle af%d\n", ifp->if_xname, sa);
                return (EAFNOSUPPORT);
        }
 
        /* Copy length before the mbuf gets invalidated. */
        len = m->m_pkthdr.len;
 
        PRIV_RLOCK(priv, &priv_tracker);
        hook = *get_hook_from_iffam(priv, iffam);
        if (hook == NULL) {
                NG_FREE_M(m);
                PRIV_RUNLOCK(priv, &priv_tracker);
                return ENETDOWN;
        }
        NG_HOOK_REF(hook);
        PRIV_RUNLOCK(priv, &priv_tracker);
 
        NG_OUTBOUND_THREAD_REF();
        NG_SEND_DATA_ONLY(error, hook, m);
        NG_OUTBOUND_THREAD_UNREF();
        NG_HOOK_UNREF(hook);
 
        /* Update stats. */
        if (error == 0) {
                if_inc_counter(ifp, IFCOUNTER_OBYTES, len);
                if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
        }
 
        return (error);
}
 
#ifdef DEBUG
/*
 * Display an ioctl to the virtual interface
 */
 
static void
ng_iface_print_ioctl(struct ifnet *ifp, int command, caddr_t data)
{
        char   *str;
 
        switch (command & IOC_DIRMASK) {
        case IOC_VOID:
                str = "IO";
                break;
        case IOC_OUT:
                str = "IOR";
                break;
        case IOC_IN:
                str = "IOW";
                break;
        case IOC_INOUT:
                str = "IORW";
                break;
        default:
                str = "IO??";
        }
        log(LOG_DEBUG, "%s: %s('%c', %d, char[%d])\n",
               ifp->if_xname,
               str,
               IOCGROUP(command),
               command & 0xff,
               IOCPARM_LEN(command));
}
#endif /* DEBUG */
 
/************************************************************************
                        NETGRAPH NODE STUFF
 ************************************************************************/
 
/*
 * Constructor for a node
 */
static int
ng_iface_constructor(node_p node)
{
        struct ifnet *ifp;
        priv_p priv;
 
        /* Allocate node and interface private structures */
        priv = malloc(sizeof(*priv), M_NETGRAPH_IFACE, M_WAITOK | M_ZERO);
        ifp = if_alloc(IFT_PROPVIRTUAL);
        if (ifp == NULL) {
                free(priv, M_NETGRAPH_IFACE);
                return (ENOMEM);
        }
 
        rm_init(&priv->lock, "ng_iface private rmlock");
 
        /* Link them together */
        ifp->if_softc = priv;
        priv->ifp = ifp;
 
        /* Get an interface unit number */
        priv->unit = alloc_unr(V_ng_iface_unit);
 
        /* Link together node and private info */
        NG_NODE_SET_PRIVATE(node, priv);
        priv->node = node;
 
        /* Initialize interface structure */
        if_initname(ifp, NG_IFACE_IFACE_NAME, priv->unit);
        ifp->if_output = ng_iface_output;
        ifp->if_start = ng_iface_start;
        ifp->if_ioctl = ng_iface_ioctl;
        ifp->if_mtu = NG_IFACE_MTU_DEFAULT;
        ifp->if_flags = (IFF_SIMPLEX|IFF_POINTOPOINT|IFF_NOARP|IFF_MULTICAST);
        ifp->if_type = IFT_PROPVIRTUAL;         /* XXX */
        ifp->if_addrlen = 0;                    /* XXX */
        ifp->if_hdrlen = 0;                     /* XXX */
        ifp->if_baudrate = 64000;               /* XXX */
        IFQ_SET_MAXLEN(&ifp->if_snd, ifqmaxlen);
        ifp->if_snd.ifq_drv_maxlen = ifqmaxlen;
        IFQ_SET_READY(&ifp->if_snd);
 
        /* Give this node the same name as the interface (if possible) */
        if (ng_name_node(node, ifp->if_xname) != 0)
                log(LOG_WARNING, "%s: can't acquire netgraph name\n",
                    ifp->if_xname);
 
        /* Attach the interface */
        if_attach(ifp);
        bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
 
        /* Done */
        return (0);
}
 
/*
 * Give our ok for a hook to be added
 */
static int
ng_iface_newhook(node_p node, hook_p hook, const char *name)
{
        const iffam_p iffam = get_iffam_from_name(name);
        const priv_p priv = NG_NODE_PRIVATE(node);
        hook_p *hookptr;
 
        if (iffam == NULL)
                return (EPFNOSUPPORT);
        PRIV_WLOCK(priv);
        hookptr = get_hook_from_iffam(priv, iffam);
        if (*hookptr != NULL) {
                PRIV_WUNLOCK(priv);
                return (EISCONN);
        }
        *hookptr = hook;
        NG_HOOK_HI_STACK(hook);
        NG_HOOK_SET_TO_INBOUND(hook);
        PRIV_WUNLOCK(priv);
        return (0);
}
 
/*
 * Receive a control message
 */
static int
ng_iface_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        const priv_p priv = NG_NODE_PRIVATE(node);
        struct ifnet *const ifp = priv->ifp;
        struct ng_mesg *resp = NULL;
        int error = 0;
        struct ng_mesg *msg;
 
        NGI_GET_MSG(item, msg);
        switch (msg->header.typecookie) {
        case NGM_IFACE_COOKIE:
                switch (msg->header.cmd) {
                case NGM_IFACE_GET_IFNAME:
                        NG_MKRESPONSE(resp, msg, IFNAMSIZ, M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        strlcpy(resp->data, ifp->if_xname, IFNAMSIZ);
                        break;
 
                case NGM_IFACE_POINT2POINT:
                case NGM_IFACE_BROADCAST:
                    {
                        /* Deny request if interface is UP */
                        if ((ifp->if_flags & IFF_UP) != 0)
                                return (EBUSY);
 
                        /* Change flags */
                        switch (msg->header.cmd) {
                        case NGM_IFACE_POINT2POINT:
                                ifp->if_flags |= IFF_POINTOPOINT;
                                ifp->if_flags &= ~IFF_BROADCAST;
                                break;
                        case NGM_IFACE_BROADCAST:
                                ifp->if_flags &= ~IFF_POINTOPOINT;
                                ifp->if_flags |= IFF_BROADCAST;
                                break;
                        }
                        break;
                    }
 
                case NGM_IFACE_GET_IFINDEX:
                        NG_MKRESPONSE(resp, msg, sizeof(uint32_t), M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        *((uint32_t *)resp->data) = priv->ifp->if_index;
                        break;
 
                default:
                        error = EINVAL;
                        break;
                }
                break;
        case NGM_FLOW_COOKIE:
                switch (msg->header.cmd) {
                case NGM_LINK_IS_UP:
                        if_link_state_change(ifp, LINK_STATE_UP);
                        break;
                case NGM_LINK_IS_DOWN:
                        if_link_state_change(ifp, LINK_STATE_DOWN);
                        break;
                default:
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        NG_RESPOND_MSG(error, node, item, resp);
        NG_FREE_MSG(msg);
        return (error);
}
 
/*
 * Recive data from a hook. Pass the packet to the correct input routine.
 */
static int
ng_iface_rcvdata(hook_p hook, item_p item)
{
        const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        const iffam_p iffam = get_iffam_from_hook(priv, hook);
        struct ifnet *const ifp = priv->ifp;
        struct epoch_tracker et;
        struct mbuf *m;
        int isr;
 
        NGI_GET_M(item, m);
        NG_FREE_ITEM(item);
        /* Sanity checks */
        KASSERT(iffam != NULL, ("%s: iffam", __func__));
        M_ASSERTPKTHDR(m);
        if ((ifp->if_flags & IFF_UP) == 0) {
                NG_FREE_M(m);
                return (ENETDOWN);
        }
 
        /* Update interface stats */
        if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
        if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
 
        /* Note receiving interface */
        m->m_pkthdr.rcvif = ifp;
 
        /* Berkeley packet filter */
        ng_iface_bpftap(ifp, m, iffam->family);
 
        /* Send packet */
        switch (iffam->family) {
#ifdef INET
        case AF_INET:
                isr = NETISR_IP;
                break;
#endif
#ifdef INET6
        case AF_INET6:
                isr = NETISR_IPV6;
                break;
#endif
        default:
                m_freem(m);
                return (EAFNOSUPPORT);
        }
        random_harvest_queue(m, sizeof(*m), RANDOM_NET_NG);
        M_SETFIB(m, ifp->if_fib);
        CURVNET_SET(ifp->if_vnet);
        NET_EPOCH_ENTER(et);
        netisr_dispatch(isr, m);
        NET_EPOCH_EXIT(et);
        CURVNET_RESTORE();
        return (0);
}
 
/*
 * Shutdown and remove the node and its associated interface.
 */
static int
ng_iface_shutdown(node_p node)
{
        const priv_p priv = NG_NODE_PRIVATE(node);
 
        /*
         * The ifnet may be in a different vnet than the netgraph node, 
         * hence we have to change the current vnet context here.
         */
        CURVNET_SET_QUIET(priv->ifp->if_vnet);
        bpfdetach(priv->ifp);
        if_detach(priv->ifp);
        if_free(priv->ifp);
        CURVNET_RESTORE();
        priv->ifp = NULL;
        free_unr(V_ng_iface_unit, priv->unit);
        rm_destroy(&priv->lock);
        free(priv, M_NETGRAPH_IFACE);
        NG_NODE_SET_PRIVATE(node, NULL);
        NG_NODE_UNREF(node);
        return (0);
}
 
/*
 * Hook disconnection. Note that we do *not* shutdown when all
 * hooks have been disconnected.
 */
static int
ng_iface_disconnect(hook_p hook)
{
        const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        const iffam_p iffam = get_iffam_from_hook(priv, hook);
 
        if (iffam == NULL)
                panic("%s", __func__);
        PRIV_WLOCK(priv);
        *get_hook_from_iffam(priv, iffam) = NULL;
        PRIV_WUNLOCK(priv);
        return (0);
}
 
/*
 * Handle loading and unloading for this node type.
 */
static int
ng_iface_mod_event(module_t mod, int event, void *data)
{
        int error = 0;
 
        switch (event) {
        case MOD_LOAD:
        case MOD_UNLOAD:
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        return (error);
}
 
static void
vnet_ng_iface_init(const void *unused)
{
 
        V_ng_iface_unit = new_unrhdr(0, 0xffff, NULL);
}
VNET_SYSINIT(vnet_ng_iface_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
    vnet_ng_iface_init, NULL);
 
static void
vnet_ng_iface_uninit(const void *unused)
{
 
        delete_unrhdr(V_ng_iface_unit);
}
VNET_SYSUNINIT(vnet_ng_iface_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
    vnet_ng_iface_uninit, NULL);