/*
 * 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: src/sys/netgraph/ng_iface.c,v 1.7.2.5 2002/07/02 23:44:02 archie Exp $
 * $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/malloc.h>
#include <sys/mbuf.h>
#include <sys/sockio.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/libkern.h>
#include <sys/thread2.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/ifq_var.h>
#include <net/netisr.h>
#include <net/bpf.h>

#include <netinet/in.h>

#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include "ng_iface.h"
#include <netgraph/cisco/ng_cisco.h>

/* 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 */
static const struct iffam gFamilies[] = {
        { AF_INET,      NG_IFACE_HOOK_INET      },
        { AF_INET6,     NG_IFACE_HOOK_INET6     },
        { AF_ATM,       NG_IFACE_HOOK_ATM       },
        { AF_NATM,      NG_IFACE_HOOK_NATM      },
};
#define NUM_FAMILIES            NELEM(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 */
};
typedef struct ng_iface_private *priv_p;

/* Interface methods */
static void     ng_iface_start(struct ifnet *ifp, struct ifaltq_subque *);
static int      ng_iface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data,
                        struct ucred *cr);
static int      ng_iface_output(struct ifnet *ifp, struct mbuf *m0,
                        struct sockaddr *dst, struct rtentry *rt0);
static void     ng_iface_bpftap(struct ifnet *ifp,
                        struct mbuf *m, sa_family_t family);
#ifdef DEBUG
static void     ng_iface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
#endif

/* Netgraph methods */
static ng_constructor_t ng_iface_constructor;
static ng_rcvmsg_t      ng_iface_rcvmsg;
static ng_shutdown_t    ng_iface_rmnode;
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);

/* Parse type for struct ng_iface_ifname */
static const struct ng_parse_fixedstring_info ng_iface_ifname_info = {
        NG_IFACE_IFACE_NAME_MAX + 1
};
static const struct ng_parse_type ng_iface_ifname_type = {
        &ng_parse_fixedstring_type,
        &ng_iface_ifname_info
};

/* Parse type for struct ng_cisco_ipaddr */
static const struct ng_parse_struct_field ng_cisco_ipaddr_type_fields[]
        = NG_CISCO_IPADDR_TYPE_INFO;
static const struct ng_parse_type ng_cisco_ipaddr_type = {
        &ng_parse_struct_type,
        &ng_cisco_ipaddr_type_fields
};

/* 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_iface_ifname_type
        },
        {
          NGM_IFACE_COOKIE,
          NGM_IFACE_POINT2POINT,
          "point2point",
          NULL,
          NULL
        },
        {
          NGM_IFACE_COOKIE,
          NGM_IFACE_BROADCAST,
          "broadcast",
          NULL,
          NULL
        },
        {
          NGM_CISCO_COOKIE,
          NGM_CISCO_GET_IPADDR,
          "getipaddr",
          NULL,
          &ng_cisco_ipaddr_type
        },
        { 0 }
};

/* Node type descriptor */
static struct ng_type typestruct = {
        NG_VERSION,
        NG_IFACE_NODE_TYPE,
        NULL,
        ng_iface_constructor,
        ng_iface_rcvmsg,
        ng_iface_rmnode,
        ng_iface_newhook,
        NULL,
        NULL,
        ng_iface_rcvdata,
        ng_iface_rcvdata,
        ng_iface_disconnect,
        ng_iface_cmds
};
NETGRAPH_INIT(iface, &typestruct);

/* We keep a bitmap indicating which unit numbers are free.
   One means the unit number is free, zero means it's taken. */
static int      *ng_iface_units = NULL;
static int      ng_iface_units_len = 0;

#define UNITS_BITSPERWORD       (sizeof(*ng_iface_units) * NBBY)

/************************************************************************
                        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);
}

/*
 * Find the first free unit number for a new interface.
 * Increase the size of the unit bitmap as necessary.
 */
static __inline__ int
ng_iface_get_unit(int *unit)
{
        int index, bit;

        for (index = 0; index < ng_iface_units_len
            && ng_iface_units[index] == 0; index++);
        if (index == ng_iface_units_len) {              /* extend array */
                int i, *newarray, newlen;

                newlen = (2 * ng_iface_units_len) + 4;
                newarray = kmalloc(newlen * sizeof(*ng_iface_units),
                                   M_NETGRAPH, M_NOWAIT);
                if (newarray == NULL)
                        return (ENOMEM);
                bcopy(ng_iface_units, newarray,
                    ng_iface_units_len * sizeof(*ng_iface_units));
                for (i = ng_iface_units_len; i < newlen; i++)
                        newarray[i] = ~0;
                if (ng_iface_units != NULL)
                        kfree(ng_iface_units, M_NETGRAPH);
                ng_iface_units = newarray;
                ng_iface_units_len = newlen;
        }
        bit = ffs(ng_iface_units[index]) - 1;
        KASSERT(bit >= 0 && bit <= UNITS_BITSPERWORD - 1,
            ("%s: word=%d bit=%d", __func__, ng_iface_units[index], bit));
        ng_iface_units[index] &= ~(1 << bit);
        *unit = (index * UNITS_BITSPERWORD) + bit;
        return (0);
}

/*
 * Free a no longer needed unit number.
 */
static __inline__ void
ng_iface_free_unit(int unit)
{
        int index, bit;

        index = unit / UNITS_BITSPERWORD;
        bit = unit % UNITS_BITSPERWORD;
        KASSERT(index < ng_iface_units_len,
            ("%s: unit=%d len=%d", __func__, unit, ng_iface_units_len));
        KASSERT((ng_iface_units[index] & (1 << bit)) == 0,
            ("%s: unit=%d is free", __func__, unit));
        ng_iface_units[index] |= (1 << bit);
        /*
         * XXX We could think about reducing the size of ng_iface_units[]
         * XXX here if the last portion is all ones
         */
}

/************************************************************************
                        INTERFACE STUFF
 ************************************************************************/

/*
 * Process an ioctl for the virtual interface
 */
static int
ng_iface_ioctl(struct ifnet *ifp, u_long command, caddr_t data,
    struct ucred *cr)
{
        struct ifreq *const ifr = (struct ifreq *) data;
        int error = 0;

#ifdef DEBUG
        ng_iface_print_ioctl(ifp, command, data);
#endif
        crit_enter();
        switch (command) {

        /* These two are mostly handled at a higher layer */
        case SIOCSIFADDR:
                ifp->if_flags |= (IFF_UP | IFF_RUNNING);
                ifq_clr_oactive(&ifp->if_snd);
                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_flags & IFF_RUNNING)) {
                                ifq_clr_oactive(&ifp->if_snd);
                                ifp->if_flags |= IFF_RUNNING;
                        }
                } else {
                        if (ifp->if_flags & IFF_RUNNING) {
                                ifp->if_flags &= ~IFF_RUNNING;
                                ifq_clr_oactive(&ifp->if_snd);
                        }
                }
                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;
        }
        crit_exit();
        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_serialized(struct ifnet *ifp, struct mbuf *m,
                           struct sockaddr *dst, struct rtentry *rt0)
{
        const priv_p priv = (priv_p) ifp->if_softc;
        const iffam_p iffam = get_iffam_from_af(dst->sa_family);
        meta_p meta = NULL;
        int len, error = 0;

        /* Check interface flags */
        if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
                m_freem(m);
                return (ENETDOWN);
        }

        /* BPF writes need to be handled specially */
        if (dst->sa_family == AF_UNSPEC) {
                if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
                        return (ENOBUFS);
                dst->sa_family = (sa_family_t)*mtod(m, int32_t *);
                m->m_data += 4;
                m->m_len -= 4;
                m->m_pkthdr.len -= 4;
        }

        /* Berkeley packet filter */
        ng_iface_bpftap(ifp, m, dst->sa_family);

        /* 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, (int)dst->sa_family);
                return (EAFNOSUPPORT);
        }

        /* Copy length before the mbuf gets invalidated */
        len = m->m_pkthdr.len;

        /* Send packet; if hook is not connected, mbuf will get freed. */
        NG_SEND_DATA(error, *get_hook_from_iffam(priv, iffam), m, meta);

        /* Update stats */
        if (error == 0) {
                IFNET_STAT_INC(ifp, obytes, len);
                IFNET_STAT_INC(ifp, opackets, 1);
        }
        return (error);
}

static int
ng_iface_output(struct ifnet *ifp, struct mbuf *m,
                struct sockaddr *dst, struct rtentry *rt0)
{
        struct ifaltq_subque *ifsq = ifq_get_subq_default(&ifp->if_snd);
        int error;

        ifsq_serialize_hw(ifsq);
        error = ng_iface_output_serialized(ifp, m, dst, rt0);
        ifsq_deserialize_hw(ifsq);

        return error;
}

/*
 * This routine should never be called
 */

static void
ng_iface_start(struct ifnet *ifp, struct ifaltq_subque *ifsq __unused)
{
        kprintf("%s: %s called?", ifp->if_xname, __func__);
}

/*
 * Flash a packet by the BPF (requires prepending 4 byte AF header)
 */
static void
ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
{
        int32_t family4 = (int32_t)family;

        KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));

        if (ifp->if_bpf) {
                bpf_gettoken();
                if (ifp->if_bpf)
                        bpf_ptap(ifp->if_bpf, m, &family, sizeof(family4));
                bpf_reltoken();
        }
}

#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 *nodep)
{
        char ifname[NG_IFACE_IFACE_NAME_MAX + 1];
        struct ifnet *ifp;
        node_p node;
        priv_p priv;
        int error = 0;

        /* Allocate node and interface private structures */
        priv = kmalloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
        if (priv == NULL)
                return (ENOMEM);
        ifp = kmalloc(sizeof(*ifp), M_NETGRAPH, M_NOWAIT | M_ZERO);
        if (ifp == NULL) {
                kfree(priv, M_NETGRAPH);
                return (ENOMEM);
        }

        /* Link them together */
        ifp->if_softc = priv;
        priv->ifp = ifp;

        /* Get an interface unit number */
        if ((error = ng_iface_get_unit(&priv->unit)) != 0) {
                kfree(ifp, M_NETGRAPH);
                kfree(priv, M_NETGRAPH);
                return (error);
        }

        /* Call generic node constructor */
        if ((error = ng_make_node_common(&typestruct, nodep)) != 0) {
                ng_iface_free_unit(priv->unit);
                kfree(ifp, M_NETGRAPH);
                kfree(priv, M_NETGRAPH);
                return (error);
        }
        node = *nodep;

        /* Link together node and private info */
        node->private = 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_watchdog = NULL;
        ifq_set_maxlen(&ifp->if_snd, IFQ_MAXLEN);
        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 */

        /* Give this node the same name as the interface (if possible) */
        bzero(ifname, sizeof(ifname));
        strlcpy(ifname, ifp->if_xname, sizeof(ifname));
        if (ng_name_node(node, ifname) != 0)
                log(LOG_WARNING, "%s: can't acquire netgraph name\n", ifname);

        /* Attach the interface */
        if_attach(ifp, NULL);
        bpfattach(ifp, DLT_NULL, sizeof(uint32_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);
        hook_p *hookptr;

        if (iffam == NULL)
                return (EPFNOSUPPORT);
        hookptr = get_hook_from_iffam((priv_p) node->private, iffam);
        if (*hookptr != NULL)
                return (EISCONN);
        *hookptr = hook;
        return (0);
}

/*
 * Receive a control message
 */
static int
ng_iface_rcvmsg(node_p node, struct ng_mesg *msg,
                const char *retaddr, struct ng_mesg **rptr)
{
        const priv_p priv = node->private;
        struct ifnet *const ifp = priv->ifp;
        struct ng_mesg *resp = NULL;
        int error = 0;

        switch (msg->header.typecookie) {
        case NGM_IFACE_COOKIE:
                switch (msg->header.cmd) {
                case NGM_IFACE_GET_IFNAME:
                    {
                        struct ng_iface_ifname *arg;

                        NG_MKRESPONSE(resp, msg, sizeof(*arg), M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        arg = (struct ng_iface_ifname *)resp->data;
                        strlcpy(arg->ngif_name, ifp->if_xname,
                            sizeof(arg->ngif_name));
                        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;
                    }

                default:
                        error = EINVAL;
                        break;
                }
                break;
        case NGM_CISCO_COOKIE:
                switch (msg->header.cmd) {
                case NGM_CISCO_GET_IPADDR:      /* we understand this too */
                    {
                        struct ifaddr_container *ifac;

                        /* Return the first configured IP address */
                        TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid],
                                      ifa_link) {
                                struct ifaddr *ifa = ifac->ifa;
                                struct ng_cisco_ipaddr *ips;

                                if (ifa->ifa_addr->sa_family != AF_INET)
                                        continue;
                                NG_MKRESPONSE(resp, msg, sizeof(ips), M_NOWAIT);
                                if (resp == NULL) {
                                        error = ENOMEM;
                                        break;
                                }
                                ips = (struct ng_cisco_ipaddr *)resp->data;
                                ips->ipaddr = ((struct sockaddr_in *)
                                                ifa->ifa_addr)->sin_addr;
                                ips->netmask = ((struct sockaddr_in *)
                                                ifa->ifa_netmask)->sin_addr;
                                break;
                        }

                        /* No IP addresses on this interface? */
                        if (ifac == NULL)
                                error = EADDRNOTAVAIL;
                        break;
                    }
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        if (rptr)
                *rptr = resp;
        else if (resp)
                kfree(resp, M_NETGRAPH);
        kfree(msg, M_NETGRAPH);
        return (error);
}

/*
 * Recive data from a hook. Pass the packet to the correct input routine.
 */
static int
ng_iface_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
{
        const priv_p priv = hook->node->private;
        const iffam_p iffam = get_iffam_from_hook(priv, hook);
        struct ifnet *const ifp = priv->ifp;
        int isr;

        /* Sanity checks */
        KASSERT(iffam != NULL, ("%s: iffam", __func__));
        KASSERT(m->m_flags & M_PKTHDR, ("%s: not pkthdr", __func__));
        if (m == NULL)
                return (EINVAL);
        if ((ifp->if_flags & IFF_UP) == 0) {
                NG_FREE_DATA(m, meta);
                return (ENETDOWN);
        }

        /* Update interface stats */
        IFNET_STAT_INC(ifp, ipackets, 1);
        IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);

        /* Note receiving interface */
        m->m_pkthdr.rcvif = ifp;

        /* Berkeley packet filter */
        ng_iface_bpftap(ifp, m, iffam->family);

        /* Ignore any meta-data */
        NG_FREE_META(meta);

        /* 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);
        }
        netisr_queue(isr, m);
        return (0);
}

/*
 * Shutdown and remove the node and its associated interface.
 */
static int
ng_iface_rmnode(node_p node)
{
        const priv_p priv = node->private;

        ng_cutlinks(node);
        ng_unname(node);
        bpfdetach(priv->ifp);
        if_detach(priv->ifp);
        kfree(priv->ifp, M_NETGRAPH);
        priv->ifp = NULL;
        ng_iface_free_unit(priv->unit);
        kfree(priv, M_NETGRAPH);
        node->private = NULL;
        ng_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 = hook->node->private;
        const iffam_p iffam = get_iffam_from_hook(priv, hook);

        if (iffam == NULL)
                panic(__func__);
        *get_hook_from_iffam(priv, iffam) = NULL;
        return (0);
}