kernel - Fix races created by a comedy of circumstansces (3)

[dragonfly.git] / sys / netgraph7 / ng_fec.c

/*
 * ng_fec.c
 */

/*-
 * Copyright (c) 2001 Berkeley Software Design, Inc.
 * Copyright (c) 2000, 2001
 *      Bill Paul <wpaul@osd.bsdi.com>.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Bill Paul.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Bill Paul 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 Bill Paul OR THE VOICES IN HIS HEAD
 * 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.
 *
 * $FreeBSD: src/sys/netgraph/ng_fec.c,v 1.30 2007/05/18 15:05:49 dwmalone Exp $
 */
/*-
 * 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>
 *
 * $Whistle: ng_fec.c,v 1.33 1999/11/01 09:24:51 julian Exp $
 */

/*
 * This module implements ethernet channel bonding using the Cisco
 * Fast EtherChannel mechanism. Two or four ports may be combined
 * into a single aggregate interface.
 *
 * Interfaces are named fec0, fec1, etc.  New nodes take the
 * first available interface name.
 *
 * This node also includes Berkeley packet filter support.
 *
 * Note that this node doesn't need to connect to any other
 * netgraph nodes in order to do its work.
 */

#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/queue.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_media.h>
#include <net/bpf.h>
#include <net/ethernet.h>

#include "opt_inet.h"
#include "opt_inet6.h"

#include <netinet/in.h>
#ifdef INET
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#endif

#ifdef INET6
#include <netinet/ip6.h>
#endif

#include "ng_message.h"
#include "netgraph.h"
#include "ng_parse.h"
#include "ng_fec.h"

/*
 * We need a way to stash a pointer to our netgraph node in the
 * ifnet structure so that receive handling works. As far as I can
 * tell, although there is an AF_NETGRAPH address family, it's only
 * used to identify sockaddr_ng structures: there is no netgraph address
 * family domain. This means the AF_NETGRAPH entry in ifp->if_afdata
 * should be unused, so we can use to hold our node context.
 */
#define IFP2NG(ifp)     ((ifp)->if_afdata[AF_NETGRAPH])

/*
 * Current fast etherchannel implementations use either 2 or 4
 * ports, so for now we limit the maximum bundle size to 4 interfaces.
 */
#define FEC_BUNDLESIZ   4

struct ng_fec_portlist {
        struct ifnet            *fec_if;
        void                    (*fec_if_input) (struct ifnet *,
                                                 struct mbuf *,
                                                 const struct pktinfo *,
                                                 int);
        int                     fec_idx;
        int                     fec_ifstat;
        struct ether_addr       fec_mac;
        SLIST_HEAD(__mclhd, ng_fec_mc)  fec_mc_head;
        TAILQ_ENTRY(ng_fec_portlist) fec_list;
};

struct ng_fec_mc {
        struct ifmultiaddr      *mc_ifma;
        SLIST_ENTRY(ng_fec_mc)    mc_entries;
};

struct ng_fec_bundle {
        TAILQ_HEAD(,ng_fec_portlist) ng_fec_ports;
        int                     fec_ifcnt;
        int                     fec_btype;
        int                     (*fec_if_output) (struct ifnet *,
                                                  struct mbuf *,
                                                  struct sockaddr *,
                                                  struct rtentry *);
};

#define FEC_BTYPE_MAC           0x01
#define FEC_BTYPE_INET          0x02
#define FEC_BTYPE_INET6         0x03

/* Node private data */
struct ng_fec_private {
        struct ifnet *ifp;
        struct ifmedia ifmedia;
        int     if_flags;
        int     if_error;               /* XXX */
        int     unit;                   /* Interface unit number */
        node_p  node;                   /* Our netgraph node */
        struct ng_fec_bundle fec_bundle;/* Aggregate bundle */
        struct callout_handle fec_ch;   /* callout handle for ticker */
};
typedef struct ng_fec_private *priv_p;

/* Interface methods */
static void     ng_fec_input(struct ifnet *, struct mbuf *,
                        const struct pktinfo *, int);
static void     ng_fec_start(struct ifnet *ifp, struct ifaltq_subque *);
static int      ng_fec_choose_port(struct ng_fec_bundle *b,
                        struct mbuf *m, struct ifnet **ifp);
static int      ng_fec_setport(struct ifnet *ifp, u_long cmd, caddr_t data);
static void     ng_fec_init(void *arg);
static void     ng_fec_stop(struct ifnet *ifp);
static int      ng_fec_ifmedia_upd(struct ifnet *ifp);
static void     ng_fec_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr);
static int      ng_fec_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
static int      ng_fec_output(struct ifnet *ifp, struct mbuf *m0,
                        struct sockaddr *dst, struct rtentry *rt0);
static void     ng_fec_tick(void *arg);
static int      ng_fec_addport(struct ng_fec_private *priv, char *iface);
static int      ng_fec_delport(struct ng_fec_private *priv, char *iface);
static int      ng_fec_ether_cmdmulti(struct ifnet *trifp, struct ng_fec_portlist *p, int set);

#ifdef DEBUG
static void     ng_fec_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
#endif

/* Netgraph methods */
static int              ng_fec_mod_event(module_t, int, void *);
static ng_constructor_t ng_fec_constructor;
static ng_rcvmsg_t      ng_fec_rcvmsg;
static ng_shutdown_t    ng_fec_shutdown;

/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_fec_cmds[] = {
        {
          NGM_FEC_COOKIE,
          NGM_FEC_ADD_IFACE,
          "add_iface",
          &ng_parse_string_type,
          NULL,
        },
        {
          NGM_FEC_COOKIE,
          NGM_FEC_DEL_IFACE,
          "del_iface",
          &ng_parse_string_type,
          NULL,
        },
        {
          NGM_FEC_COOKIE,
          NGM_FEC_SET_MODE_MAC,
          "set_mode_mac",
          NULL,
          NULL,
        },
        {
          NGM_FEC_COOKIE,
          NGM_FEC_SET_MODE_INET,
          "set_mode_inet",
          NULL,
          NULL,
        },
        { 0 }
};

/* Node type descriptor */
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_FEC_NODE_TYPE,
        .mod_event =    ng_fec_mod_event,
        .constructor =  ng_fec_constructor,
        .rcvmsg =       ng_fec_rcvmsg,
        .shutdown =     ng_fec_shutdown,
        .cmdlist =      ng_fec_cmds,
};
NETGRAPH_INIT(fec, &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_fec_units = NULL;
static int      ng_fec_units_len = 0;
static int      ng_units_in_use = 0;

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

static struct mtx       ng_fec_mtx;

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

        mtx_lock(&ng_fec_mtx);
        for (index = 0; index < ng_fec_units_len
            && ng_fec_units[index] == 0; index++);
        if (index == ng_fec_units_len) {                /* extend array */
                int i, *newarray, newlen;

                newlen = (2 * ng_fec_units_len) + 4;
                newarray = kmalloc(newlen * sizeof(*ng_fec_units),
                                   M_NETGRAPH, M_WAITOK | M_NULLOK);
                if (newarray == NULL) {
                        mtx_unlock(&ng_fec_mtx);
                        return (ENOMEM);
                }
                bcopy(ng_fec_units, newarray,
                    ng_fec_units_len * sizeof(*ng_fec_units));
                for (i = ng_fec_units_len; i < newlen; i++)
                        newarray[i] = ~0;
                if (ng_fec_units != NULL)
                        kfree(ng_fec_units, M_NETGRAPH);
                ng_fec_units = newarray;
                ng_fec_units_len = newlen;
        }
        bit = ffs(ng_fec_units[index]) - 1;
        KASSERT(bit >= 0 && bit <= UNITS_BITSPERWORD - 1,
            ("%s: word=%d bit=%d", __func__, ng_fec_units[index], bit));
        ng_fec_units[index] &= ~(1 << bit);
        *unit = (index * UNITS_BITSPERWORD) + bit;
        ng_units_in_use++;
        mtx_unlock(&ng_fec_mtx);
        return (0);
}

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

        index = unit / UNITS_BITSPERWORD;
        bit = unit % UNITS_BITSPERWORD;
        mtx_lock(&ng_fec_mtx);
        KASSERT(index < ng_fec_units_len,
            ("%s: unit=%d len=%d", __func__, unit, ng_fec_units_len));
        KASSERT((ng_fec_units[index] & (1 << bit)) == 0,
            ("%s: unit=%d is free", __func__, unit));
        ng_fec_units[index] |= (1 << bit);
        /*
         * XXX We could think about reducing the size of ng_fec_units[]
         * XXX here if the last portion is all ones
         * XXX At least free it if no more units
         * Needed if we are to eventually be able to unload.
         */
        ng_units_in_use--;
        if (ng_units_in_use == 0) { /* XXX make SMP safe */
                kfree(ng_fec_units, M_NETGRAPH);
                ng_fec_units_len = 0;
                ng_fec_units = NULL;
        }
        mtx_unlock(&ng_fec_mtx);
}

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

static int
ng_fec_addport(struct ng_fec_private *priv, char *iface)
{
        struct ng_fec_bundle    *b;
        struct ifnet            *ifp, *bifp;
        struct ng_fec_portlist  *p, *new;

        if (priv == NULL || iface == NULL)
                return(EINVAL);

        b = &priv->fec_bundle;
        ifp = priv->ifp;

        /* Only allow reconfiguration if not running. */
        if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
                kprintf("fec%d: can't add new iface; bundle is running\n",
                    priv->unit);
                return (EINVAL);
        }

        /* Find the interface */
        bifp = ifunit(iface);
        if (bifp == NULL) {
                kprintf("fec%d: tried to add iface %s, which "
                    "doesn't seem to exist\n", priv->unit, iface);
                return(ENOENT);
        }

        /* See if we have room in the bundle */
        if (b->fec_ifcnt == FEC_BUNDLESIZ) {
                kprintf("fec%d: can't add new iface; bundle is full\n",
                    priv->unit);
                return(ENOSPC);
        }

        /* See if the interface is already in the bundle */
        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                if (p->fec_if == bifp) {
                        kprintf("fec%d: iface %s is already in this "
                            "bundle\n", priv->unit, iface);
                        return(EINVAL);
                }
        }

        /*
         * All interfaces must use the same output vector. Once the
         * user attaches an interface of one type, make all subsequent
         * interfaces have the same output vector.
         */
        if (b->fec_if_output != NULL) {
                if (b->fec_if_output != bifp->if_output) {
                        kprintf("fec%d: iface %s is not the same type "
                            "as the other interface(s) already in "
                            "the bundle\n", priv->unit, iface);
                        return(EINVAL);
                }
        }

        /* Allocate new list entry. */
        new = kmalloc(sizeof(struct ng_fec_portlist), M_NETGRAPH,
                      M_WAITOK | M_NULLOK);
        if (new == NULL)
                return(ENOMEM);

        IF_AFDATA_LOCK(bifp);
        IFP2NG(bifp) = priv->node;
        IF_AFDATA_UNLOCK(bifp);

        /*
         * If this is the first interface added to the bundle,
         * use its MAC address for the virtual interface (and,
         * by extension, all the other ports in the bundle).
         */
        if (b->fec_ifcnt == 0)
                if_setlladdr(ifp, IF_LLADDR(bifp), ETHER_ADDR_LEN);

        b->fec_btype = FEC_BTYPE_MAC;
        new->fec_idx = b->fec_ifcnt;
        b->fec_ifcnt++;

        /* Initialise the list of multicast addresses that we own. */
        SLIST_INIT(&new->fec_mc_head);

        /* Save the real MAC address. */
        bcopy(IF_LLADDR(bifp),
            (char *)&new->fec_mac, ETHER_ADDR_LEN);

        /* Set up phony MAC address. */
        if_setlladdr(bifp, IF_LLADDR(ifp), ETHER_ADDR_LEN);

        /* Save original input vector */
        new->fec_if_input = bifp->if_input;

        /* Override it with our own */
        bifp->if_input = ng_fec_input;

        /* Save output vector too. */
        if (b->fec_if_output == NULL)
                b->fec_if_output = bifp->if_output;

        /* Add to the queue */
        new->fec_if = bifp;
        new->fec_ifstat = -1;
        TAILQ_INSERT_TAIL(&b->ng_fec_ports, new, fec_list);

        /* Add multicast addresses to this port. */
        ng_fec_ether_cmdmulti(ifp, new, 1);

        return(0);
}

static int
ng_fec_delport(struct ng_fec_private *priv, char *iface)
{
        struct ng_fec_bundle    *b;
        struct ifnet            *ifp, *bifp;
        struct ng_fec_portlist  *p;

        if (priv == NULL || iface == NULL)
                return(EINVAL);

        b = &priv->fec_bundle;
        ifp = priv->ifp;

        /* Only allow reconfiguration if not running. */
        if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
                kprintf("fec%d: can't remove iface; bundle is running\n",
                    priv->unit);
                return (EINVAL);
        }

        /* Find the interface */
        bifp = ifunit(iface);
        if (bifp == NULL) {
                kprintf("fec%d: tried to remove iface %s, which "
                    "doesn't seem to exist\n", priv->unit, iface);
                return(ENOENT);
        }

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                if (p->fec_if == bifp)
                        break;
        }

        if (p == NULL) {
                kprintf("fec%d: tried to remove iface %s which "
                    "is not in our bundle\n", priv->unit, iface);
                return(EINVAL);
        }

        /* Stop interface */
        bifp->if_flags &= ~IFF_UP;
        (*bifp->if_ioctl)(bifp, SIOCSIFFLAGS, NULL);

        /* Restore MAC address. */
        if_setlladdr(bifp, (u_char *)&p->fec_mac, ETHER_ADDR_LEN);

        /* Restore input vector */
        bifp->if_input = p->fec_if_input;

        /* Remove our node context pointer. */
        IF_AFDATA_LOCK(bifp);
        IFP2NG(bifp) = NULL;
        IF_AFDATA_UNLOCK(bifp);

        /* Delete port */
        TAILQ_REMOVE(&b->ng_fec_ports, p, fec_list);
        kfree(p, M_NETGRAPH);
        b->fec_ifcnt--;

        if (b->fec_ifcnt == 0)
                b->fec_if_output = NULL;

        return(0);
}

static int
ng_fec_ether_cmdmulti(struct ifnet *trifp, struct ng_fec_portlist *p, int set)
{
        struct ifnet *ifp = p->fec_if;
        struct ng_fec_mc *mc;
        struct ifmultiaddr *ifma, *rifma = NULL;
        struct sockaddr_dl sdl;
        int error;

        bzero((char *)&sdl, sizeof(sdl));
        sdl.sdl_len = sizeof(sdl);
        sdl.sdl_family = AF_LINK;
        sdl.sdl_type = IFT_ETHER;
        sdl.sdl_alen = ETHER_ADDR_LEN;
        sdl.sdl_index = ifp->if_index;

        if (set) {
                TAILQ_FOREACH(ifma, &trifp->if_multiaddrs, ifma_link) {
                        if (ifma->ifma_addr->sa_family != AF_LINK)
                                continue;
                        bcopy(LLADDR((struct sockaddr_dl *)ifma->ifma_addr),
                            LLADDR(&sdl), ETHER_ADDR_LEN);

                        error = if_addmulti(ifp, (struct sockaddr *)&sdl, &rifma);
                        if (error)
                                return (error);
                        mc = kmalloc(sizeof(struct ng_fec_mc), M_DEVBUF, M_WAITOK | M_NULLOK);
                        if (mc == NULL)
                                return (ENOMEM);
                        mc->mc_ifma = rifma;
                        SLIST_INSERT_HEAD(&p->fec_mc_head, mc, mc_entries);
                }
        } else {
                while ((mc = SLIST_FIRST(&p->fec_mc_head)) != NULL) {
                        SLIST_REMOVE(&p->fec_mc_head, mc, ng_fec_mc, mc_entries);
                        if_delmulti_ifma(mc->mc_ifma);
                        kfree(mc, M_DEVBUF);
                }
        }
        return (0);
}

static int
ng_fec_ether_setmulti(struct ifnet *ifp)
{
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ng_fec_portlist  *p;

        priv = ifp->if_softc;
        b = &priv->fec_bundle;

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                /* First, remove any existing filter entries. */
                ng_fec_ether_cmdmulti(ifp, p, 0);
                /* copy all addresses from the fec interface to the port */
                ng_fec_ether_cmdmulti(ifp, p, 1);
        }
        return (0);
}

/*
 * Pass an ioctl command down to all the underyling interfaces in a
 * bundle. Used for setting flags.
 */

static int 
ng_fec_setport(struct ifnet *ifp, u_long command, caddr_t data)
{
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ifnet            *oifp;
        struct ng_fec_portlist  *p;

        priv = ifp->if_softc;
        b = &priv->fec_bundle;

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                oifp = p->fec_if;
                if (oifp != NULL)
                        (*oifp->if_ioctl)(oifp, command, data);
        }

        return(0);
}

static void
ng_fec_init(void *arg)
{
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ifnet            *ifp, *bifp;
        struct ng_fec_portlist  *p;

        priv = arg;
        ifp = priv->ifp;
        b = &priv->fec_bundle;

        if (b->fec_ifcnt != 2 && b->fec_ifcnt != FEC_BUNDLESIZ) {
                kprintf("fec%d: invalid bundle "
                    "size: %d\n", priv->unit,
                    b->fec_ifcnt);
                return;
        }

        ng_fec_stop(ifp);

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                bifp = p->fec_if;
                bifp->if_flags |= IFF_UP;
                (*bifp->if_ioctl)(bifp, SIOCSIFFLAGS, NULL);
                /* mark iface as up and let the monitor check it */
                p->fec_ifstat = -1;
        }

        ifp->if_drv_flags &= ~(IFF_DRV_OACTIVE);
        ifp->if_drv_flags |= IFF_DRV_RUNNING;

        priv->fec_ch = timeout(ng_fec_tick, priv, hz);

        return;
}

static void
ng_fec_stop(struct ifnet *ifp)
{
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ifnet            *bifp;
        struct ng_fec_portlist  *p;

        priv = ifp->if_softc;
        b = &priv->fec_bundle;

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                bifp = p->fec_if;
                bifp->if_flags &= ~IFF_UP;
                (*bifp->if_ioctl)(bifp, SIOCSIFFLAGS, NULL);
        }

        untimeout(ng_fec_tick, priv, priv->fec_ch);

        ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);

        return;
}

static void
ng_fec_tick(void *arg)
{
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ifmediareq       ifmr;
        struct ifnet            *ifp;
        struct ng_fec_portlist  *p;
        int                     error = 0;

        priv = arg;
        b = &priv->fec_bundle;

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                bzero((char *)&ifmr, sizeof(ifmr));
                ifp = p->fec_if;
                error = (*ifp->if_ioctl)(ifp, SIOCGIFMEDIA, (caddr_t)&ifmr);
                if (error) {
                        kprintf("fec%d: failed to check status "
                            "of link %s\n", priv->unit, ifp->if_xname);
                        continue;
                }

                if (ifmr.ifm_status & IFM_AVALID) {
                        if (ifmr.ifm_status & IFM_ACTIVE) {
                                if (p->fec_ifstat == -1 ||
                                    p->fec_ifstat == 0) {
                                        p->fec_ifstat = 1;
                                        kprintf("fec%d: port %s in bundle "
                                            "is up\n", priv->unit,
                                            ifp->if_xname);
                                }
                        } else {
                                if (p->fec_ifstat == -1 ||
                                    p->fec_ifstat == 1) {
                                        p->fec_ifstat = 0;
                                        kprintf("fec%d: port %s in bundle "
                                            "is down\n", priv->unit,
                                            ifp->if_xname);
                                }
                        }
                }
        }

        ifp = priv->ifp;
        if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                priv->fec_ch = timeout(ng_fec_tick, priv, hz);

        return;
}

static int
ng_fec_ifmedia_upd(struct ifnet *ifp)
{
        return(0);
}

static void ng_fec_ifmedia_sts(struct ifnet *ifp,
        struct ifmediareq *ifmr)
{
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ng_fec_portlist  *p;

        priv = ifp->if_softc;
        b = &priv->fec_bundle;

        ifmr->ifm_status = IFM_AVALID;
        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                if (p->fec_ifstat == 1) {
                        ifmr->ifm_status |= IFM_ACTIVE;
                        break;
                }
        }

        return;
}

/*
 * Process an ioctl for the virtual interface
 */
static int
ng_fec_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
{
        struct ifreq *const ifr = (struct ifreq *) data;
        int s, error = 0;
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;

        priv = ifp->if_softc;
        b = &priv->fec_bundle;

#ifdef DEBUG
        ng_fec_print_ioctl(ifp, command, data);
#endif
        s = splimp();
        switch (command) {

        /* These two are mostly handled at a higher layer */
        case SIOCSIFADDR:
        case SIOCGIFADDR:
                error = ether_ioctl(ifp, command, data);
                break;

        case SIOCSIFMTU:
                if (ifr->ifr_mtu >= NG_FEC_MTU_MIN &&
                    ifr->ifr_mtu <= NG_FEC_MTU_MAX) {
                        struct ng_fec_portlist *p;
                        struct ifnet *bifp;

                        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                                bifp = p->fec_if;
                                error = (*bifp->if_ioctl)(bifp, SIOCSIFMTU,
                                    data);
                                if (error != 0)
                                        break;
                        }
                        if (error == 0)
                                ifp->if_mtu = ifr->ifr_mtu;
                } else
                        error = EINVAL;
                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)) {
                                /* Sanity. */
                                if (b->fec_ifcnt != 2 &&
                                    b->fec_ifcnt != FEC_BUNDLESIZ) {
                                        kprintf("fec%d: invalid bundle "
                                            "size: %d\n", priv->unit,
                                            b->fec_ifcnt);
                                        error = EINVAL;
                                        break;
                                }
                                ng_fec_init(priv);
                        }
                        /*
                         * Bubble down changes in promisc mode to
                         * underlying interfaces.
                         */
                        if ((ifp->if_flags & IFF_PROMISC) !=
                            (priv->if_flags & IFF_PROMISC)) {
                                ng_fec_setport(ifp, command, data);
                                priv->if_flags = ifp->if_flags;
                        }
                } else {
                        if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                                ng_fec_stop(ifp);
                }
                break;

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                ng_fec_ether_setmulti(ifp);
                error = 0;
                break;
        case SIOCGIFMEDIA:
        case SIOCSIFMEDIA:
                error = ifmedia_ioctl(ifp, ifr, &priv->ifmedia, command);
                break;
        /* Stuff that's not supported */
        case SIOCSIFPHYS:
                error = EOPNOTSUPP;
                break;

        default:
                error = EINVAL;
                break;
        }
        (void) splx(s);
        return (error);
}

/*
 * This routine spies on mbufs received by underlying network device
 * drivers. When we add an interface to our bundle, we override its
 * if_input routine with a pointer to ng_fec_input(). This means we
 * get to look at all the device's packets before sending them to the
 * real ether_input() for processing by the stack. Once we verify the
 * packet comes from an interface that's been aggregated into
 * our bundle, we fix up the rcvif pointer and increment our
 * packet counters so that it looks like the frames are actually
 * coming from us.
 */
static void 
ng_fec_input(struct ifnet *ifp, struct mbuf *m0)
{
        struct ng_node          *node;
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ifnet            *bifp;
        struct ng_fec_portlist  *p;

        /* Sanity check */
        if (ifp == NULL || m0 == NULL)
                return;

        node = IFP2NG(ifp);

        /* Sanity check part II */
        if (node == NULL)
                return;

        priv = NG_NODE_PRIVATE(node);
        b = &priv->fec_bundle;
        bifp = priv->ifp;

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                if (p->fec_if == m0->m_pkthdr.rcvif)
                        break;
        }

        /* Wasn't meant for us; leave this frame alone. */
        if (p == NULL)
                return;

        /*
         * Check for a BPF tap on the underlying interface. This
         * is mainly a debugging aid: it allows tcpdump-ing of an
         * individual interface in a bundle to work, which it
         * otherwise would not. BPF tapping of our own aggregate
         * interface will occur once we call ether_input().
         */
        BPF_MTAP(m0->m_pkthdr.rcvif, m0);

        /* Convince the system that this is our frame. */
        m0->m_pkthdr.rcvif = bifp;

        /*
         * Count bytes on an individual interface in a bundle.
         * The bytes will also be added to the aggregate interface
         * once we call ether_input().
         */
        ifp->if_ibytes += m0->m_pkthdr.len;

        bifp->if_ipackets++;
        bifp->if_input(bifp, m0, NULL, -1);

        return;
}

/*
 * Take a quick peek at the packet and see if it's ok for us to use
 * the inet or inet6 hash methods on it, if they're enabled. We do
 * this by setting flags in the mbuf header. Once we've made up our
 * mind what to do, we pass the frame to output vector for further
 * processing.
 */

static int
ng_fec_output(struct ifnet *ifp, struct mbuf *m,
                struct sockaddr *dst, struct rtentry *rt0)
{
        const priv_p priv = (priv_p) ifp->if_softc;
        struct ng_fec_bundle *b;
        int error;

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

        b = &priv->fec_bundle;

        switch (b->fec_btype) {
        case FEC_BTYPE_MAC:
                m->m_flags |= M_FEC_MAC;
                break;
#ifdef INET
        case FEC_BTYPE_INET:
                /*
                 * We can't use the INET address port selection
                 * scheme if this isn't an INET packet.
                 */
                if (dst->sa_family == AF_INET)
                        m->m_flags |= M_FEC_INET;
#ifdef INET6
                else if (dst->sa_family == AF_INET6)
                        m->m_flags |= M_FEC_INET6;
#endif
                else {
#ifdef DEBUG
                        if_printf(ifp, "can't do inet aggregation of non "
                            "inet packet\n");
#endif
                        m->m_flags |= M_FEC_MAC;
                }
                break;
#endif
        default:
                if_printf(ifp, "bogus hash type: %d\n",
                    b->fec_btype);
                m_freem(m);
                return(EINVAL);
                break;
        }

        /*
         * Pass the frame to the output vector for all the protocol
         * handling. This will put the ethernet header on the packet
         * for us.
         */
        priv->if_error = 0;
        error = (*b->fec_if_output)(ifp, m, dst, rt0);
        if (priv->if_error && !error)
                error = priv->if_error;

        return(error);
}

/*
 * Apply a hash to the source and destination addresses in the packet
 * in order to select an interface. Also check link status and handle
 * dead links accordingly.
 */

static int
ng_fec_choose_port(struct ng_fec_bundle *b,
        struct mbuf *m, struct ifnet **ifp)
{
        struct ether_header     *eh;
        struct mbuf             *m0;
#ifdef INET
        struct ip               *ip;
#ifdef INET6
        struct ip6_hdr          *ip6;
#endif
#endif

        struct ng_fec_portlist  *p;
        int                     port = 0, mask;

        /*
         * If there are only two ports, mask off all but the
         * last bit for XORing. If there are 4, mask off all
         * but the last 2 bits.
         */
        mask = b->fec_ifcnt == 2 ? 0x1 : 0x3;
        eh = mtod(m, struct ether_header *);
#ifdef INET
        ip = (struct ip *)(mtod(m, char *) +
            sizeof(struct ether_header));
#ifdef INET6
        ip6 = (struct ip6_hdr *)(mtod(m, char *) +
            sizeof(struct ether_header));
#endif
#endif

        /*
         * The fg_fec_output() routine is supposed to leave a
         * flag for us in the mbuf that tells us what hash to
         * use, but sometimes a new mbuf is prepended to the
         * chain, so we have to search every mbuf in the chain
         * to find the flags.
         */
        m0 = m;
        while (m0) {
                if (m0->m_flags & (M_FEC_MAC|M_FEC_INET|M_FEC_INET6))
                        break;
                m0 = m0->m_next;
        }
        if (m0 == NULL)
                return(EINVAL);

        switch (m0->m_flags & (M_FEC_MAC|M_FEC_INET|M_FEC_INET6)) {
        case M_FEC_MAC:
                port = (eh->ether_dhost[5] ^
                    eh->ether_shost[5]) & mask;
                break;
#ifdef INET
        case M_FEC_INET:
                port = (ntohl(ip->ip_dst.s_addr) ^
                    ntohl(ip->ip_src.s_addr)) & mask;
                break;
#ifdef INET6
        case M_FEC_INET6:
                port = (ip6->ip6_dst.s6_addr[15] ^
                    ip6->ip6_dst.s6_addr[15]) & mask;
                break;
#endif
#endif
        default:
                return(EINVAL);
                        break;
        }

        TAILQ_FOREACH(p, &b->ng_fec_ports, fec_list) {
                if (port == p->fec_idx)
                        break;
        }

        /*
         * Now that we've chosen a port, make sure it's
         * alive. If it's not alive, cycle through the bundle
         * looking for a port that is alive. If we don't find
         * any, return an error.
         */
        if (p->fec_ifstat != 1) {
                struct ng_fec_portlist  *n = NULL;

                n = TAILQ_NEXT(p, fec_list);
                if (n == NULL)
                        n = TAILQ_FIRST(&b->ng_fec_ports);
                while (n != p) {
                        if (n->fec_ifstat == 1)
                                break;
                        n = TAILQ_NEXT(n, fec_list);
                        if (n == NULL)
                                n = TAILQ_FIRST(&b->ng_fec_ports);
                }
                if (n == p)
                        return(EAGAIN);
                p = n;
        }

        *ifp = p->fec_if;

        return(0);
}

/*
 * Now that the packet has been run through ether_output(), yank it
 * off our own send queue and stick it on the queue for the appropriate
 * underlying physical interface. Note that if the interface's send
 * queue is full, we save an error status in our private netgraph
 * space which will eventually be handed up to ng_fec_output(), which
 * will return it to the rest of the IP stack. We need to do this
 * in order to duplicate the effect of ether_output() returning ENOBUFS
 * when it detects that an interface's send queue is full. There's no
 * other way to signal the error status from here since the if_start()
 * routine is spec'ed to return void.
 *
 * Once the frame is queued, we call ether_output_frame() to initiate
 * transmission.
 */
static void
ng_fec_start(struct ifnet *ifp, struct ifaltq_subque *ifsq)
{
        struct ng_fec_private   *priv;
        struct ng_fec_bundle    *b;
        struct ifnet            *oifp = NULL;
        struct mbuf             *m0;
        int                     error;

        priv = ifp->if_softc;
        b = &priv->fec_bundle;

        m0 = ifq_dequeue(&ifp->if_snd);
        if (m0 == NULL)
                return;

        BPF_MTAP(ifp, m0);

        /* Queue up packet on the proper port. */
        error = ng_fec_choose_port(b, m0, &oifp);
        if (error) {
                ifp->if_ierrors++;
                m_freem(m0);
                priv->if_error = ENOBUFS;
                return;
        }
        ifp->if_opackets++;

        ifnet_deserialize_tx(ifp, ifsq);
        error = ifq_dispatch(oifp, m0, NULL);
        ifnet_serialize_tx(ifp, ifsq);

        priv->if_error = error;
}

#ifdef DEBUG
/*
 * Display an ioctl to the virtual interface
 */

static void
ng_fec_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_fec_constructor(node_p node)
{
        char ifname[NG_FEC_FEC_NAME_MAX + 1];
        struct ifnet *ifp;
        priv_p priv;
        const uint8_t eaddr[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
        struct ng_fec_bundle *b;
        int error = 0;

        /* Allocate node and interface private structures */
        priv = kmalloc(sizeof(*priv), M_NETGRAPH,
                       M_WAITOK | M_NULLOK | M_ZERO);
        if (priv == NULL)
                return (ENOMEM);

        ifp = priv->ifp = if_alloc(IFT_ETHER);
        if (ifp == NULL) {
                kfree(priv, M_NETGRAPH);
                return (ENOSPC);
        }
        b = &priv->fec_bundle;

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

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

        /* Link together node and private info */
        NG_NODE_SET_PRIVATE(node, priv);
        priv->node = node;

        /* Initialize interface structure */
        if_initname(ifp, NG_FEC_FEC_NAME, priv->unit);
        ifp->if_start = ng_fec_start;
        ifp->if_ioctl = ng_fec_ioctl;
        ifp->if_init = ng_fec_init;
        ifp->if_watchdog = NULL;
        ifq_set_maxlen(&ifp->if_snd, IFQ_MAXLEN);
        ifp->if_mtu = NG_FEC_MTU_DEFAULT;
        ifp->if_flags = (IFF_SIMPLEX|IFF_BROADCAST|IFF_MULTICAST);
        ifp->if_addrlen = 0;                    /* XXX */
        ifp->if_hdrlen = 0;                     /* XXX */
        ifp->if_baudrate = 100000000;           /* XXX */
        TAILQ_INIT(&ifp->if_addrhead); /* XXX useless - done in if_attach */

        /* 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 */
        ether_ifattach(ifp, eaddr);
        callout_handle_init(&priv->fec_ch);

        /* Override output method with our own */
        ifp->if_output = ng_fec_output;

        TAILQ_INIT(&b->ng_fec_ports);
        b->fec_ifcnt = 0;

        ifmedia_init(&priv->ifmedia, 0,
            ng_fec_ifmedia_upd, ng_fec_ifmedia_sts);
        ifmedia_add(&priv->ifmedia, IFM_ETHER|IFM_NONE, 0, NULL);
        ifmedia_set(&priv->ifmedia, IFM_ETHER|IFM_NONE);

        /* Done */
        return (0);
}

/*
 * Receive a control message
 */
static int
ng_fec_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        const priv_p priv = NG_NODE_PRIVATE(node);
        struct ng_fec_bundle    *b;
        struct ng_mesg *resp = NULL;
        struct ng_mesg *msg;
        char *ifname;
        int error = 0;

        NGI_GET_MSG(item, msg);
        b = &priv->fec_bundle;

        switch (msg->header.typecookie) {
        case NGM_FEC_COOKIE:
                switch (msg->header.cmd) {
                case NGM_FEC_ADD_IFACE:
                        ifname = msg->data;
                        error = ng_fec_addport(priv, ifname);
                        break;
                case NGM_FEC_DEL_IFACE:
                        ifname = msg->data;
                        error = ng_fec_delport(priv, ifname);
                        break;
                case NGM_FEC_SET_MODE_MAC:
                        b->fec_btype = FEC_BTYPE_MAC;
                        break;
#ifdef INET
                case NGM_FEC_SET_MODE_INET:
                        b->fec_btype = FEC_BTYPE_INET;
                        break;
#ifdef INET6
                case NGM_FEC_SET_MODE_INET6:
                        b->fec_btype = FEC_BTYPE_INET6;
                        break;
#endif
#endif
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        NG_RESPOND_MSG(error, node, item, resp);
        NG_FREE_MSG(msg);
        return (error);
}

/*
 * Shutdown and remove the node and its associated interface.
 */
static int
ng_fec_shutdown(node_p node)
{
        const priv_p priv = NG_NODE_PRIVATE(node);
        struct ng_fec_bundle *b;
        struct ng_fec_portlist  *p;

        b = &priv->fec_bundle;
        ng_fec_stop(priv->ifp);

        while (!TAILQ_EMPTY(&b->ng_fec_ports)) {
                p = TAILQ_FIRST(&b->ng_fec_ports);
                ng_fec_ether_cmdmulti(priv->ifp, p, 0);
                ng_fec_delport(priv, p->fec_if->if_xname);
        }

        ether_ifdetach(priv->ifp);
        if_free_type(priv->ifp, IFT_ETHER);
        ifmedia_removeall(&priv->ifmedia);
        ng_fec_free_unit(priv->unit);
        kfree(priv, M_NETGRAPH);
        NG_NODE_SET_PRIVATE(node, NULL);
        NG_NODE_UNREF(node);
        return (0);
}

/*
 * Handle loading and unloading for this node type.
 */
static int
ng_fec_mod_event(module_t mod, int event, void *data)
{
        int error = 0;

        switch (event) {
        case MOD_LOAD:
                mtx_init(&ng_fec_mtx, "ng_fec", NULL, MTX_DEF);
                break;
        case MOD_UNLOAD:
                mtx_destroy(&ng_fec_mtx);
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        return (error);
}