FreeBSD/Linux Kernel Cross Reference
sys/net/if_bridge.c

     /*      $NetBSD: if_bridge.c,v 1.31 2005/06/01 19:45:34 jdc Exp $       */
     
     /*
      * Copyright 2001 Wasabi Systems, Inc.
      * All rights reserved.
      *
      * Written by Jason R. Thorpe for Wasabi Systems, Inc.
      *
      * 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 for the NetBSD Project by
     *      Wasabi Systems, Inc.
     * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     *    or promote products derived from this software without specific prior
     *    written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
     * 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.
     */
    
    /*
     * Copyright (c) 1999, 2000 Jason L. Wright (jason@thought.net)
     * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR 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.
     *
     * OpenBSD: if_bridge.c,v 1.60 2001/06/15 03:38:33 itojun Exp
     */
    
    /*
     * Network interface bridge support.
     *
     * TODO:
     *
     *      - Currently only supports Ethernet-like interfaces (Ethernet,
     *        802.11, VLANs on Ethernet, etc.)  Figure out a nice way
     *        to bridge other types of interfaces (FDDI-FDDI, and maybe
     *        consider heterogenous bridges).
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/10.4/sys/net/if_bridge.c 313066 2017-02-01 21:44:50Z kp $");
    
    #include "opt_inet.h"
    #include "opt_inet6.h"
    
    #include <sys/param.h>
    #include <sys/mbuf.h>
    #include <sys/malloc.h>
    #include <sys/protosw.h>
    #include <sys/systm.h>
    #include <sys/jail.h>
    #include <sys/time.h>
    #include <sys/socket.h> /* for net/if.h */
    #include <sys/sockio.h>
    #include <sys/ctype.h>  /* string functions */
    #include <sys/kernel.h>
    #include <sys/random.h>
    #include <sys/syslog.h>
    #include <sys/sysctl.h>
    #include <vm/uma.h>
    #include <sys/module.h>
    #include <sys/priv.h>
   #include <sys/proc.h>
   #include <sys/lock.h>
   #include <sys/mutex.h>
   
   #include <net/bpf.h>
   #include <net/if.h>
   #include <net/if_clone.h>
   #include <net/if_dl.h>
   #include <net/if_types.h>
   #include <net/if_var.h>
   #include <net/pfil.h>
   #include <net/vnet.h>
   
   #include <netinet/in.h> /* for struct arpcom */
   #include <netinet/in_systm.h>
   #include <netinet/in_var.h>
   #include <netinet/ip.h>
   #include <netinet/ip_var.h>
   #ifdef INET6
   #include <netinet/ip6.h>
   #include <netinet6/ip6_var.h>
   #include <netinet6/in6_ifattach.h>
   #endif
   #if defined(INET) || defined(INET6)
   #include <netinet/ip_carp.h>
   #endif
   #include <machine/in_cksum.h>
   #include <netinet/if_ether.h> /* for struct arpcom */
   #include <net/bridgestp.h>
   #include <net/if_bridgevar.h>
   #include <net/if_llc.h>
   #include <net/if_vlan_var.h>
   
   #include <net/route.h>
   
   /*
    * Size of the route hash table.  Must be a power of two.
    */
   #ifndef BRIDGE_RTHASH_SIZE
   #define BRIDGE_RTHASH_SIZE              1024
   #endif
   
   #define BRIDGE_RTHASH_MASK              (BRIDGE_RTHASH_SIZE - 1)
   
   /*
    * Default maximum number of addresses to cache.
    */
   #ifndef BRIDGE_RTABLE_MAX
   #define BRIDGE_RTABLE_MAX               2000
   #endif
   
   /*
    * Timeout (in seconds) for entries learned dynamically.
    */
   #ifndef BRIDGE_RTABLE_TIMEOUT
   #define BRIDGE_RTABLE_TIMEOUT           (20 * 60)       /* same as ARP */
   #endif
   
   /*
    * Number of seconds between walks of the route list.
    */
   #ifndef BRIDGE_RTABLE_PRUNE_PERIOD
   #define BRIDGE_RTABLE_PRUNE_PERIOD      (5 * 60)
   #endif
   
   /*
    * List of capabilities to possibly mask on the member interface.
    */
   #define BRIDGE_IFCAPS_MASK              (IFCAP_TOE|IFCAP_TSO|IFCAP_TXCSUM|\
                                            IFCAP_TXCSUM_IPV6)
   
   /*
    * List of capabilities to strip
    */
   #define BRIDGE_IFCAPS_STRIP             IFCAP_LRO
   
   /*
    * Bridge interface list entry.
    */
   struct bridge_iflist {
           LIST_ENTRY(bridge_iflist) bif_next;
           struct ifnet            *bif_ifp;       /* member if */
           struct bstp_port        bif_stp;        /* STP state */
           uint32_t                bif_flags;      /* member if flags */
           int                     bif_savedcaps;  /* saved capabilities */
           uint32_t                bif_addrmax;    /* max # of addresses */
           uint32_t                bif_addrcnt;    /* cur. # of addresses */
           uint32_t                bif_addrexceeded;/* # of address violations */
   };
   
   /*
    * Bridge route node.
    */
   struct bridge_rtnode {
           LIST_ENTRY(bridge_rtnode) brt_hash;     /* hash table linkage */
           LIST_ENTRY(bridge_rtnode) brt_list;     /* list linkage */
           struct bridge_iflist    *brt_dst;       /* destination if */
           unsigned long           brt_expire;     /* expiration time */
           uint8_t                 brt_flags;      /* address flags */
           uint8_t                 brt_addr[ETHER_ADDR_LEN];
           uint16_t                brt_vlan;       /* vlan id */
   };
   #define brt_ifp                 brt_dst->bif_ifp
   
   /*
    * Software state for each bridge.
    */
   struct bridge_softc {
           struct ifnet            *sc_ifp;        /* make this an interface */
           LIST_ENTRY(bridge_softc) sc_list;
           struct mtx              sc_mtx;
           struct cv               sc_cv;
           uint32_t                sc_brtmax;      /* max # of addresses */
           uint32_t                sc_brtcnt;      /* cur. # of addresses */
           uint32_t                sc_brttimeout;  /* rt timeout in seconds */
           struct callout          sc_brcallout;   /* bridge callout */
           uint32_t                sc_iflist_ref;  /* refcount for sc_iflist */
           uint32_t                sc_iflist_xcnt; /* refcount for sc_iflist */
           LIST_HEAD(, bridge_iflist) sc_iflist;   /* member interface list */
           LIST_HEAD(, bridge_rtnode) *sc_rthash;  /* our forwarding table */
           LIST_HEAD(, bridge_rtnode) sc_rtlist;   /* list version of above */
           uint32_t                sc_rthash_key;  /* key for hash */
           LIST_HEAD(, bridge_iflist) sc_spanlist; /* span ports list */
           struct bstp_state       sc_stp;         /* STP state */
           uint32_t                sc_brtexceeded; /* # of cache drops */
           struct ifnet            *sc_ifaddr;     /* member mac copied from */
           u_char                  sc_defaddr[6];  /* Default MAC address */
   };
   
   static struct mtx       bridge_list_mtx;
   eventhandler_tag        bridge_detach_cookie = NULL;
   
   int     bridge_rtable_prune_period = BRIDGE_RTABLE_PRUNE_PERIOD;
   
   uma_zone_t bridge_rtnode_zone;
   
   static int      bridge_clone_create(struct if_clone *, int, caddr_t);
   static void     bridge_clone_destroy(struct ifnet *);
   
   static int      bridge_ioctl(struct ifnet *, u_long, caddr_t);
   static void     bridge_mutecaps(struct bridge_softc *);
   static void     bridge_set_ifcap(struct bridge_softc *, struct bridge_iflist *,
                       int);
   static void     bridge_ifdetach(void *arg __unused, struct ifnet *);
   static void     bridge_init(void *);
   static void     bridge_dummynet(struct mbuf *, struct ifnet *);
   static void     bridge_stop(struct ifnet *, int);
   static int      bridge_transmit(struct ifnet *, struct mbuf *);
   static void     bridge_qflush(struct ifnet *);
   static struct mbuf *bridge_input(struct ifnet *, struct mbuf *);
   static int      bridge_output(struct ifnet *, struct mbuf *, struct sockaddr *,
                       struct rtentry *);
   static int      bridge_enqueue(struct bridge_softc *, struct ifnet *,
                       struct mbuf *);
   static void     bridge_rtdelete(struct bridge_softc *, struct ifnet *ifp, int);
   
   static void     bridge_forward(struct bridge_softc *, struct bridge_iflist *,
                       struct mbuf *m);
   
   static void     bridge_timer(void *);
   
   static void     bridge_broadcast(struct bridge_softc *, struct ifnet *,
                       struct mbuf *, int);
   static void     bridge_span(struct bridge_softc *, struct mbuf *);
   
   static int      bridge_rtupdate(struct bridge_softc *, const uint8_t *,
                       uint16_t, struct bridge_iflist *, int, uint8_t);
   static struct ifnet *bridge_rtlookup(struct bridge_softc *, const uint8_t *,
                       uint16_t);
   static void     bridge_rttrim(struct bridge_softc *);
   static void     bridge_rtage(struct bridge_softc *);
   static void     bridge_rtflush(struct bridge_softc *, int);
   static int      bridge_rtdaddr(struct bridge_softc *, const uint8_t *,
                       uint16_t);
   
   static void     bridge_rtable_init(struct bridge_softc *);
   static void     bridge_rtable_fini(struct bridge_softc *);
   
   static int      bridge_rtnode_addr_cmp(const uint8_t *, const uint8_t *);
   static struct bridge_rtnode *bridge_rtnode_lookup(struct bridge_softc *,
                       const uint8_t *, uint16_t);
   static int      bridge_rtnode_insert(struct bridge_softc *,
                       struct bridge_rtnode *);
   static void     bridge_rtnode_destroy(struct bridge_softc *,
                       struct bridge_rtnode *);
   static void     bridge_rtable_expire(struct ifnet *, int);
   static void     bridge_state_change(struct ifnet *, int);
   
   static struct bridge_iflist *bridge_lookup_member(struct bridge_softc *,
                       const char *name);
   static struct bridge_iflist *bridge_lookup_member_if(struct bridge_softc *,
                       struct ifnet *ifp);
   static void     bridge_delete_member(struct bridge_softc *,
                       struct bridge_iflist *, int);
   static void     bridge_delete_span(struct bridge_softc *,
                       struct bridge_iflist *);
   
   static int      bridge_ioctl_add(struct bridge_softc *, void *);
   static int      bridge_ioctl_del(struct bridge_softc *, void *);
   static int      bridge_ioctl_gifflags(struct bridge_softc *, void *);
   static int      bridge_ioctl_sifflags(struct bridge_softc *, void *);
   static int      bridge_ioctl_scache(struct bridge_softc *, void *);
   static int      bridge_ioctl_gcache(struct bridge_softc *, void *);
   static int      bridge_ioctl_gifs(struct bridge_softc *, void *);
   static int      bridge_ioctl_rts(struct bridge_softc *, void *);
   static int      bridge_ioctl_saddr(struct bridge_softc *, void *);
   static int      bridge_ioctl_sto(struct bridge_softc *, void *);
   static int      bridge_ioctl_gto(struct bridge_softc *, void *);
   static int      bridge_ioctl_daddr(struct bridge_softc *, void *);
   static int      bridge_ioctl_flush(struct bridge_softc *, void *);
   static int      bridge_ioctl_gpri(struct bridge_softc *, void *);
   static int      bridge_ioctl_spri(struct bridge_softc *, void *);
   static int      bridge_ioctl_ght(struct bridge_softc *, void *);
   static int      bridge_ioctl_sht(struct bridge_softc *, void *);
   static int      bridge_ioctl_gfd(struct bridge_softc *, void *);
   static int      bridge_ioctl_sfd(struct bridge_softc *, void *);
   static int      bridge_ioctl_gma(struct bridge_softc *, void *);
   static int      bridge_ioctl_sma(struct bridge_softc *, void *);
   static int      bridge_ioctl_sifprio(struct bridge_softc *, void *);
   static int      bridge_ioctl_sifcost(struct bridge_softc *, void *);
   static int      bridge_ioctl_sifmaxaddr(struct bridge_softc *, void *);
   static int      bridge_ioctl_addspan(struct bridge_softc *, void *);
   static int      bridge_ioctl_delspan(struct bridge_softc *, void *);
   static int      bridge_ioctl_gbparam(struct bridge_softc *, void *);
   static int      bridge_ioctl_grte(struct bridge_softc *, void *);
   static int      bridge_ioctl_gifsstp(struct bridge_softc *, void *);
   static int      bridge_ioctl_sproto(struct bridge_softc *, void *);
   static int      bridge_ioctl_stxhc(struct bridge_softc *, void *);
   static int      bridge_pfil(struct mbuf **, struct ifnet *, struct ifnet *,
                       int);
   static int      bridge_ip_checkbasic(struct mbuf **mp);
   #ifdef INET6
   static int      bridge_ip6_checkbasic(struct mbuf **mp);
   #endif /* INET6 */
   static int      bridge_fragment(struct ifnet *, struct mbuf **mp,
                       struct ether_header *, int, struct llc *);
   static void     bridge_linkstate(struct ifnet *ifp);
   static void     bridge_linkcheck(struct bridge_softc *sc);
   
   extern void (*bridge_linkstate_p)(struct ifnet *ifp);
   
   /* The default bridge vlan is 1 (IEEE 802.1Q-2003 Table 9-2) */
   #define VLANTAGOF(_m)   \
       (_m->m_flags & M_VLANTAG) ? EVL_VLANOFTAG(_m->m_pkthdr.ether_vtag) : 1
   
   static struct bstp_cb_ops bridge_ops = {
           .bcb_state = bridge_state_change,
           .bcb_rtage = bridge_rtable_expire
   };
   
   SYSCTL_DECL(_net_link);
   static SYSCTL_NODE(_net_link, IFT_BRIDGE, bridge, CTLFLAG_RW, 0, "Bridge");
   
   static int pfil_onlyip = 1; /* only pass IP[46] packets when pfil is enabled */
   static int pfil_bridge = 1; /* run pfil hooks on the bridge interface */
   static int pfil_member = 1; /* run pfil hooks on the member interface */
   static int pfil_ipfw = 0;   /* layer2 filter with ipfw */
   static int pfil_ipfw_arp = 0;   /* layer2 filter with ipfw */
   static int pfil_local_phys = 0; /* run pfil hooks on the physical interface for
                                      locally destined packets */
   static int log_stp   = 0;   /* log STP state changes */
   static int bridge_inherit_mac = 0;   /* share MAC with first bridge member */
   TUNABLE_INT("net.link.bridge.pfil_onlyip", &pfil_onlyip);
   SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_onlyip, CTLFLAG_RW,
       &pfil_onlyip, 0, "Only pass IP packets when pfil is enabled");
   TUNABLE_INT("net.link.bridge.ipfw_arp", &pfil_ipfw_arp);
   SYSCTL_INT(_net_link_bridge, OID_AUTO, ipfw_arp, CTLFLAG_RW,
       &pfil_ipfw_arp, 0, "Filter ARP packets through IPFW layer2");
   TUNABLE_INT("net.link.bridge.pfil_bridge", &pfil_bridge);
   SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_bridge, CTLFLAG_RW,
       &pfil_bridge, 0, "Packet filter on the bridge interface");
   TUNABLE_INT("net.link.bridge.pfil_member", &pfil_member);
   SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_member, CTLFLAG_RW,
       &pfil_member, 0, "Packet filter on the member interface");
   TUNABLE_INT("net.link.bridge.pfil_local_phys", &pfil_local_phys);
   SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_local_phys, CTLFLAG_RW,
       &pfil_local_phys, 0,
       "Packet filter on the physical interface for locally destined packets");
   TUNABLE_INT("net.link.bridge.log_stp", &log_stp);
   SYSCTL_INT(_net_link_bridge, OID_AUTO, log_stp, CTLFLAG_RW,
       &log_stp, 0, "Log STP state changes");
   TUNABLE_INT("net.link.bridge.inherit_mac", &bridge_inherit_mac);
   SYSCTL_INT(_net_link_bridge, OID_AUTO, inherit_mac, CTLFLAG_RW,
       &bridge_inherit_mac, 0,
       "Inherit MAC address from the first bridge member");
   
   static VNET_DEFINE(int, allow_llz_overlap) = 0;
   #define V_allow_llz_overlap     VNET(allow_llz_overlap)
   SYSCTL_VNET_INT(_net_link_bridge, OID_AUTO, allow_llz_overlap, CTLFLAG_RW,
       &VNET_NAME(allow_llz_overlap), 0, "Allow overlap of link-local scope "
       "zones of a bridge interface and the member interfaces");
   
   struct bridge_control {
           int     (*bc_func)(struct bridge_softc *, void *);
           int     bc_argsize;
           int     bc_flags;
   };
   
   #define BC_F_COPYIN             0x01    /* copy arguments in */
   #define BC_F_COPYOUT            0x02    /* copy arguments out */
   #define BC_F_SUSER              0x04    /* do super-user check */
   
   const struct bridge_control bridge_control_table[] = {
           { bridge_ioctl_add,             sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
           { bridge_ioctl_del,             sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_gifflags,        sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_COPYOUT },
           { bridge_ioctl_sifflags,        sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_scache,          sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
           { bridge_ioctl_gcache,          sizeof(struct ifbrparam),
             BC_F_COPYOUT },
   
           { bridge_ioctl_gifs,            sizeof(struct ifbifconf),
             BC_F_COPYIN|BC_F_COPYOUT },
           { bridge_ioctl_rts,             sizeof(struct ifbaconf),
             BC_F_COPYIN|BC_F_COPYOUT },
   
           { bridge_ioctl_saddr,           sizeof(struct ifbareq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_sto,             sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
           { bridge_ioctl_gto,             sizeof(struct ifbrparam),
             BC_F_COPYOUT },
   
           { bridge_ioctl_daddr,           sizeof(struct ifbareq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_flush,           sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_gpri,            sizeof(struct ifbrparam),
             BC_F_COPYOUT },
           { bridge_ioctl_spri,            sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_ght,             sizeof(struct ifbrparam),
             BC_F_COPYOUT },
           { bridge_ioctl_sht,             sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_gfd,             sizeof(struct ifbrparam),
             BC_F_COPYOUT },
           { bridge_ioctl_sfd,             sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_gma,             sizeof(struct ifbrparam),
             BC_F_COPYOUT },
           { bridge_ioctl_sma,             sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_sifprio,         sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_sifcost,         sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_addspan,         sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
           { bridge_ioctl_delspan,         sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_gbparam,         sizeof(struct ifbropreq),
             BC_F_COPYOUT },
   
           { bridge_ioctl_grte,            sizeof(struct ifbrparam),
             BC_F_COPYOUT },
   
           { bridge_ioctl_gifsstp,         sizeof(struct ifbpstpconf),
             BC_F_COPYIN|BC_F_COPYOUT },
   
           { bridge_ioctl_sproto,          sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_stxhc,           sizeof(struct ifbrparam),
             BC_F_COPYIN|BC_F_SUSER },
   
           { bridge_ioctl_sifmaxaddr,      sizeof(struct ifbreq),
             BC_F_COPYIN|BC_F_SUSER },
   
   };
   const int bridge_control_table_size =
       sizeof(bridge_control_table) / sizeof(bridge_control_table[0]);
   
   LIST_HEAD(, bridge_softc) bridge_list;
   
   static struct if_clone *bridge_cloner;
   static const char bridge_name[] = "bridge";
   
   static int
   bridge_modevent(module_t mod, int type, void *data)
   {
   
           switch (type) {
           case MOD_LOAD:
                   mtx_init(&bridge_list_mtx, "if_bridge list", NULL, MTX_DEF);
                   bridge_cloner = if_clone_simple(bridge_name,
                       bridge_clone_create, bridge_clone_destroy, 0);
                   bridge_rtnode_zone = uma_zcreate("bridge_rtnode",
                       sizeof(struct bridge_rtnode), NULL, NULL, NULL, NULL,
                       UMA_ALIGN_PTR, 0);
                   LIST_INIT(&bridge_list);
                   bridge_input_p = bridge_input;
                   bridge_output_p = bridge_output;
                   bridge_dn_p = bridge_dummynet;
                   bridge_linkstate_p = bridge_linkstate;
                   bridge_detach_cookie = EVENTHANDLER_REGISTER(
                       ifnet_departure_event, bridge_ifdetach, NULL,
                       EVENTHANDLER_PRI_ANY);
                   break;
           case MOD_UNLOAD:
                   EVENTHANDLER_DEREGISTER(ifnet_departure_event,
                       bridge_detach_cookie);
                   if_clone_detach(bridge_cloner);
                   uma_zdestroy(bridge_rtnode_zone);
                   bridge_input_p = NULL;
                   bridge_output_p = NULL;
                   bridge_dn_p = NULL;
                   bridge_linkstate_p = NULL;
                   mtx_destroy(&bridge_list_mtx);
                   break;
           default:
                   return (EOPNOTSUPP);
           }
           return (0);
   }
   
   static moduledata_t bridge_mod = {
           "if_bridge",
           bridge_modevent,
           0
   };
   
   DECLARE_MODULE(if_bridge, bridge_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
   MODULE_DEPEND(if_bridge, bridgestp, 1, 1, 1);
   
   /*
    * handler for net.link.bridge.ipfw
    */
   static int
   sysctl_pfil_ipfw(SYSCTL_HANDLER_ARGS)
   {
           int enable = pfil_ipfw;
           int error;
   
           error = sysctl_handle_int(oidp, &enable, 0, req);
           enable = (enable) ? 1 : 0;
   
           if (enable != pfil_ipfw) {
                   pfil_ipfw = enable;
   
                   /*
                    * Disable pfil so that ipfw doesnt run twice, if the user
                    * really wants both then they can re-enable pfil_bridge and/or
                    * pfil_member. Also allow non-ip packets as ipfw can filter by
                    * layer2 type.
                    */
                   if (pfil_ipfw) {
                           pfil_onlyip = 0;
                           pfil_bridge = 0;
                           pfil_member = 0;
                   }
           }
   
           return (error);
   }
   SYSCTL_PROC(_net_link_bridge, OID_AUTO, ipfw, CTLTYPE_INT|CTLFLAG_RW,
               &pfil_ipfw, 0, &sysctl_pfil_ipfw, "I", "Layer2 filter with IPFW");
   
   /*
    * bridge_clone_create:
    *
    *      Create a new bridge instance.
    */
   static int
   bridge_clone_create(struct if_clone *ifc, int unit, caddr_t params)
   {
           struct bridge_softc *sc, *sc2;
           struct ifnet *bifp, *ifp;
           int fb, retry;
           unsigned long hostid;
   
           sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
           ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
           if (ifp == NULL) {
                   free(sc, M_DEVBUF);
                   return (ENOSPC);
           }
   
           BRIDGE_LOCK_INIT(sc);
           sc->sc_brtmax = BRIDGE_RTABLE_MAX;
           sc->sc_brttimeout = BRIDGE_RTABLE_TIMEOUT;
   
           /* Initialize our routing table. */
           bridge_rtable_init(sc);
   
           callout_init_mtx(&sc->sc_brcallout, &sc->sc_mtx, 0);
   
           LIST_INIT(&sc->sc_iflist);
           LIST_INIT(&sc->sc_spanlist);
   
           ifp->if_softc = sc;
           if_initname(ifp, bridge_name, unit);
           ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
           ifp->if_ioctl = bridge_ioctl;
           ifp->if_transmit = bridge_transmit;
           ifp->if_qflush = bridge_qflush;
           ifp->if_init = bridge_init;
           ifp->if_type = IFT_BRIDGE;
   
           /*
            * Generate an ethernet address with a locally administered address.
            *
            * Since we are using random ethernet addresses for the bridge, it is
            * possible that we might have address collisions, so make sure that
            * this hardware address isn't already in use on another bridge.
            * The first try uses the hostid and falls back to arc4rand().
            */
           fb = 0;
           getcredhostid(curthread->td_ucred, &hostid);
           do {
                   if (fb || hostid == 0) {
                           arc4rand(sc->sc_defaddr, ETHER_ADDR_LEN, 1);
                           sc->sc_defaddr[0] &= ~1;/* clear multicast bit */
                           sc->sc_defaddr[0] |= 2; /* set the LAA bit */
                   } else {
                           sc->sc_defaddr[0] = 0x2;
                           sc->sc_defaddr[1] = (hostid >> 24) & 0xff;
                           sc->sc_defaddr[2] = (hostid >> 16) & 0xff;
                           sc->sc_defaddr[3] = (hostid >> 8 ) & 0xff;
                           sc->sc_defaddr[4] =  hostid        & 0xff;
                           sc->sc_defaddr[5] = ifp->if_dunit & 0xff;
                   }
   
                   fb = 1;
                   retry = 0;
                   mtx_lock(&bridge_list_mtx);
                   LIST_FOREACH(sc2, &bridge_list, sc_list) {
                           bifp = sc2->sc_ifp;
                           if (memcmp(sc->sc_defaddr,
                               IF_LLADDR(bifp), ETHER_ADDR_LEN) == 0) {
                                   retry = 1;
                                   break;
                           }
                   }
                   mtx_unlock(&bridge_list_mtx);
           } while (retry == 1);
   
           bstp_attach(&sc->sc_stp, &bridge_ops);
           ether_ifattach(ifp, sc->sc_defaddr);
           /* Now undo some of the damage... */
           ifp->if_baudrate = 0;
           ifp->if_type = IFT_BRIDGE;
   
           mtx_lock(&bridge_list_mtx);
           LIST_INSERT_HEAD(&bridge_list, sc, sc_list);
           mtx_unlock(&bridge_list_mtx);
   
           return (0);
   }
   
   /*
    * bridge_clone_destroy:
    *
    *      Destroy a bridge instance.
    */
   static void
   bridge_clone_destroy(struct ifnet *ifp)
   {
           struct bridge_softc *sc = ifp->if_softc;
           struct bridge_iflist *bif;
   
           BRIDGE_LOCK(sc);
   
           bridge_stop(ifp, 1);
           ifp->if_flags &= ~IFF_UP;
   
           while ((bif = LIST_FIRST(&sc->sc_iflist)) != NULL)
                   bridge_delete_member(sc, bif, 0);
   
           while ((bif = LIST_FIRST(&sc->sc_spanlist)) != NULL) {
                   bridge_delete_span(sc, bif);
           }
   
           BRIDGE_UNLOCK(sc);
   
           callout_drain(&sc->sc_brcallout);
   
           mtx_lock(&bridge_list_mtx);
           LIST_REMOVE(sc, sc_list);
           mtx_unlock(&bridge_list_mtx);
   
           bstp_detach(&sc->sc_stp);
           ether_ifdetach(ifp);
           if_free(ifp);
   
           /* Tear down the routing table. */
           bridge_rtable_fini(sc);
   
           BRIDGE_LOCK_DESTROY(sc);
           free(sc, M_DEVBUF);
   }
   
   /*
    * bridge_ioctl:
    *
    *      Handle a control request from the operator.
    */
   static int
   bridge_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
   {
           struct bridge_softc *sc = ifp->if_softc;
           struct ifreq *ifr = (struct ifreq *)data;
           struct bridge_iflist *bif;
           struct thread *td = curthread;
           union {
                   struct ifbreq ifbreq;
                   struct ifbifconf ifbifconf;
                   struct ifbareq ifbareq;
                   struct ifbaconf ifbaconf;
                   struct ifbrparam ifbrparam;
                   struct ifbropreq ifbropreq;
           } args;
           struct ifdrv *ifd = (struct ifdrv *) data;
           const struct bridge_control *bc;
           int error = 0;
   
           switch (cmd) {
   
           case SIOCADDMULTI:
           case SIOCDELMULTI:
                   break;
   
           case SIOCGDRVSPEC:
           case SIOCSDRVSPEC:
                   if (ifd->ifd_cmd >= bridge_control_table_size) {
                           error = EINVAL;
                           break;
                   }
                   bc = &bridge_control_table[ifd->ifd_cmd];
   
                   if (cmd == SIOCGDRVSPEC &&
                       (bc->bc_flags & BC_F_COPYOUT) == 0) {
                           error = EINVAL;
                           break;
                   }
                   else if (cmd == SIOCSDRVSPEC &&
                       (bc->bc_flags & BC_F_COPYOUT) != 0) {
                           error = EINVAL;
                           break;
                   }
   
                   if (bc->bc_flags & BC_F_SUSER) {
                           error = priv_check(td, PRIV_NET_BRIDGE);
                           if (error)
                                   break;
                   }
   
                   if (ifd->ifd_len != bc->bc_argsize ||
                       ifd->ifd_len > sizeof(args)) {
                           error = EINVAL;
                           break;
                   }
   
                   bzero(&args, sizeof(args));
                   if (bc->bc_flags & BC_F_COPYIN) {
                           error = copyin(ifd->ifd_data, &args, ifd->ifd_len);
                           if (error)
                                   break;
                   }
   
                   BRIDGE_LOCK(sc);
                   error = (*bc->bc_func)(sc, &args);
                   BRIDGE_UNLOCK(sc);
                   if (error)
                           break;
   
                   if (bc->bc_flags & BC_F_COPYOUT)
                           error = copyout(&args, ifd->ifd_data, ifd->ifd_len);
   
                   break;
   
           case SIOCSIFFLAGS:
                   if (!(ifp->if_flags & IFF_UP) &&
                       (ifp->if_drv_flags & IFF_DRV_RUNNING)) {
                           /*
                            * If interface is marked down and it is running,
                            * then stop and disable it.
                            */
                           BRIDGE_LOCK(sc);
                           bridge_stop(ifp, 1);
                           BRIDGE_UNLOCK(sc);
                   } else if ((ifp->if_flags & IFF_UP) &&
                       !(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
                           /*
                            * If interface is marked up and it is stopped, then
                            * start it.
                            */
                           (*ifp->if_init)(sc);
                   }
                   break;
   
           case SIOCSIFMTU:
                   if (ifr->ifr_mtu < 576) {
                           error = EINVAL;
                           break;
                   }
                   if (LIST_EMPTY(&sc->sc_iflist)) {
                           sc->sc_ifp->if_mtu = ifr->ifr_mtu;
                           break;
                   }
                   BRIDGE_LOCK(sc);
                   LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                           if (bif->bif_ifp->if_mtu != ifr->ifr_mtu) {
                                   log(LOG_NOTICE, "%s: invalid MTU: %lu(%s)"
                                       " != %d\n", sc->sc_ifp->if_xname,
                                       bif->bif_ifp->if_mtu,
                                       bif->bif_ifp->if_xname, ifr->ifr_mtu);
                                   error = EINVAL;
                                   break;
                           }
                   }
                   if (!error)
                           sc->sc_ifp->if_mtu = ifr->ifr_mtu;
                   BRIDGE_UNLOCK(sc);
                   break;
           default:
                   /*
                    * drop the lock as ether_ioctl() will call bridge_start() and
                    * cause the lock to be recursed.
                    */
                   error = ether_ioctl(ifp, cmd, data);
                   break;
           }
   
           return (error);
   }
   
   /*
    * bridge_mutecaps:
    *
    *      Clear or restore unwanted capabilities on the member interface
    */
   static void
   bridge_mutecaps(struct bridge_softc *sc)
   {
           struct bridge_iflist *bif;
           int enabled, mask;
   
           /* Initial bitmask of capabilities to test */
           mask = BRIDGE_IFCAPS_MASK;
   
           LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                   /* Every member must support it or its disabled */
                   mask &= bif->bif_savedcaps;
           }
   
           BRIDGE_XLOCK(sc);
           LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                   enabled = bif->bif_ifp->if_capenable;
                   enabled &= ~BRIDGE_IFCAPS_STRIP;
                   /* strip off mask bits and enable them again if allowed */
                   enabled &= ~BRIDGE_IFCAPS_MASK;
                   enabled |= mask;
                   BRIDGE_UNLOCK(sc);
                   bridge_set_ifcap(sc, bif, enabled);
                   BRIDGE_LOCK(sc);
           }
           BRIDGE_XDROP(sc);
   
   }
   
   static void
   bridge_set_ifcap(struct bridge_softc *sc, struct bridge_iflist *bif, int set)
   {
           struct ifnet *ifp = bif->bif_ifp;
           struct ifreq ifr;
           int error;
   
           BRIDGE_UNLOCK_ASSERT(sc);
   
           bzero(&ifr, sizeof(ifr));
           ifr.ifr_reqcap = set;
   
           if (ifp->if_capenable != set) {
                   error = (*ifp->if_ioctl)(ifp, SIOCSIFCAP, (caddr_t)&ifr);
                   if (error)
                           if_printf(sc->sc_ifp,
                               "error setting interface capabilities on %s\n",
                               ifp->if_xname);
           }
   }
   
   /*
    * bridge_lookup_member:
    *
    *      Lookup a bridge member interface.
    */
   static struct bridge_iflist *
   bridge_lookup_member(struct bridge_softc *sc, const char *name)
   {
           struct bridge_iflist *bif;
           struct ifnet *ifp;
   
           BRIDGE_LOCK_ASSERT(sc);
   
           LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                   ifp = bif->bif_ifp;
                   if (strcmp(ifp->if_xname, name) == 0)
                           return (bif);
           }
   
           return (NULL);
   }
   
   /*
    * bridge_lookup_member_if:
    *
    *      Lookup a bridge member interface by ifnet*.
    */
   static struct bridge_iflist *
   bridge_lookup_member_if(struct bridge_softc *sc, struct ifnet *member_ifp)
   {
           struct bridge_iflist *bif;
   
           BRIDGE_LOCK_ASSERT(sc);
   
           LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                   if (bif->bif_ifp == member_ifp)
                           return (bif);
           }
   
           return (NULL);
   }
   
   /*
    * bridge_delete_member:
    *
    *      Delete the specified member interface.
    */
   static void
   bridge_delete_member(struct bridge_softc *sc, struct bridge_iflist *bif,
       int gone)
   {
           struct ifnet *ifs = bif->bif_ifp;
           struct ifnet *fif = NULL;
   
           BRIDGE_LOCK_ASSERT(sc);
   
           if (bif->bif_flags & IFBIF_STP)
                   bstp_disable(&bif->bif_stp);
   
           ifs->if_bridge = NULL;
           BRIDGE_XLOCK(sc);
           LIST_REMOVE(bif, bif_next);
           BRIDGE_XDROP(sc);
   
           /*
            * If removing the interface that gave the bridge its mac address, set
            * the mac address of the bridge to the address of the next member, or
            * to its default address if no members are left.
            */
           if (bridge_inherit_mac && sc->sc_ifaddr == ifs) {
                   if (LIST_EMPTY(&sc->sc_iflist)) {
                           bcopy(sc->sc_defaddr,
                               IF_LLADDR(sc->sc_ifp), ETHER_ADDR_LEN);
                           sc->sc_ifaddr = NULL;
                   } else {
                           fif = LIST_FIRST(&sc->sc_iflist)->bif_ifp;
                           bcopy(IF_LLADDR(fif),
                               IF_LLADDR(sc->sc_ifp), ETHER_ADDR_LEN);
                           sc->sc_ifaddr = fif;
                   }
                   EVENTHANDLER_INVOKE(iflladdr_event, sc->sc_ifp);
           }
   
           bridge_linkcheck(sc);
           bridge_mutecaps(sc);    /* recalcuate now this interface is removed */
           bridge_rtdelete(sc, ifs, IFBF_FLUSHALL);
           KASSERT(bif->bif_addrcnt == 0,
               ("%s: %d bridge routes referenced", __func__, bif->bif_addrcnt));
   
           BRIDGE_UNLOCK(sc);
           if (!gone) {
                   switch (ifs->if_type) {
                   case IFT_ETHER:
                   case IFT_L2VLAN:
                           /*
                            * Take the interface out of promiscuous mode, but only
                            * if it was promiscuous in the first place. It might
                            * not be if we're in the bridge_ioctl_add() error path.
                            */
                           if (ifs->if_flags & IFF_PROMISC)
                                   (void) ifpromisc(ifs, 0);
                          break;
  
                  case IFT_GIF:
                          break;
  
                  default:
  #ifdef DIAGNOSTIC
                          panic("bridge_delete_member: impossible");
  #endif
                          break;
                  }
                  /* reneable any interface capabilities */
                  bridge_set_ifcap(sc, bif, bif->bif_savedcaps);
          }
          bstp_destroy(&bif->bif_stp);    /* prepare to free */
          BRIDGE_LOCK(sc);
          free(bif, M_DEVBUF);
  }
  
  /*
   * bridge_delete_span:
   *
   *      Delete the specified span interface.
   */
  static void
  bridge_delete_span(struct bridge_softc *sc, struct bridge_iflist *bif)
  {
          BRIDGE_LOCK_ASSERT(sc);
  
          KASSERT(bif->bif_ifp->if_bridge == NULL,
              ("%s: not a span interface", __func__));
  
          LIST_REMOVE(bif, bif_next);
          free(bif, M_DEVBUF);
  }
  
  static int
  bridge_ioctl_add(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif = NULL;
          struct ifnet *ifs;
          int error = 0;
  
          ifs = ifunit(req->ifbr_ifsname);
          if (ifs == NULL)
                  return (ENOENT);
          if (ifs->if_ioctl == NULL)      /* must be supported */
                  return (EINVAL);
  
          /* If it's in the span list, it can't be a member. */
          LIST_FOREACH(bif, &sc->sc_spanlist, bif_next)
                  if (ifs == bif->bif_ifp)
                          return (EBUSY);
  
          if (ifs->if_bridge == sc)
                  return (EEXIST);
  
          if (ifs->if_bridge != NULL)
                  return (EBUSY);
  
          switch (ifs->if_type) {
          case IFT_ETHER:
          case IFT_L2VLAN:
          case IFT_GIF:
                  /* permitted interface types */
                  break;
          default:
                  return (EINVAL);
          }
  
  #ifdef INET6
          /*
           * Two valid inet6 addresses with link-local scope must not be
           * on the parent interface and the member interfaces at the
           * same time.  This restriction is needed to prevent violation
           * of link-local scope zone.  Attempts to add a member
           * interface which has inet6 addresses when the parent has
           * inet6 triggers removal of all inet6 addresses on the member
           * interface.
           */
  
          /* Check if the parent interface has a link-local scope addr. */
          if (V_allow_llz_overlap == 0 &&
              in6ifa_llaonifp(sc->sc_ifp) != NULL) {
                  /*
                   * If any, remove all inet6 addresses from the member
                   * interfaces.
                   */
                  BRIDGE_XLOCK(sc);
                  LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                          if (in6ifa_llaonifp(bif->bif_ifp)) {
                                  BRIDGE_UNLOCK(sc);
                                  in6_ifdetach(bif->bif_ifp);
                                  BRIDGE_LOCK(sc);
                                  if_printf(sc->sc_ifp,
                                      "IPv6 addresses on %s have been removed "
                                      "before adding it as a member to prevent "
                                      "IPv6 address scope violation.\n",
                                      bif->bif_ifp->if_xname);
                          }
                  }
                  BRIDGE_XDROP(sc);
                  if (in6ifa_llaonifp(ifs)) {
                          BRIDGE_UNLOCK(sc);
                          in6_ifdetach(ifs);
                          BRIDGE_LOCK(sc);
                          if_printf(sc->sc_ifp,
                              "IPv6 addresses on %s have been removed "
                              "before adding it as a member to prevent "
                              "IPv6 address scope violation.\n",
                              ifs->if_xname);
                  }
          }
  #endif
          /* Allow the first Ethernet member to define the MTU */
          if (LIST_EMPTY(&sc->sc_iflist))
                  sc->sc_ifp->if_mtu = ifs->if_mtu;
          else if (sc->sc_ifp->if_mtu != ifs->if_mtu) {
                  if_printf(sc->sc_ifp, "invalid MTU: %lu(%s) != %lu\n",
                      ifs->if_mtu, ifs->if_xname, sc->sc_ifp->if_mtu);
                  return (EINVAL);
          }
  
          bif = malloc(sizeof(*bif), M_DEVBUF, M_NOWAIT|M_ZERO);
          if (bif == NULL)
                  return (ENOMEM);
  
          bif->bif_ifp = ifs;
          bif->bif_flags = IFBIF_LEARNING | IFBIF_DISCOVER;
          bif->bif_savedcaps = ifs->if_capenable;
  
          /*
           * Assign the interface's MAC address to the bridge if it's the first
           * member and the MAC address of the bridge has not been changed from
           * the default randomly generated one.
           */
          if (bridge_inherit_mac && LIST_EMPTY(&sc->sc_iflist) &&
              !memcmp(IF_LLADDR(sc->sc_ifp), sc->sc_defaddr, ETHER_ADDR_LEN)) {
                  bcopy(IF_LLADDR(ifs), IF_LLADDR(sc->sc_ifp), ETHER_ADDR_LEN);
                  sc->sc_ifaddr = ifs;
                  EVENTHANDLER_INVOKE(iflladdr_event, sc->sc_ifp);
          }
  
          ifs->if_bridge = sc;
          bstp_create(&sc->sc_stp, &bif->bif_stp, bif->bif_ifp);
          /*
           * XXX: XLOCK HERE!?!
           *
           * NOTE: insert_***HEAD*** should be safe for the traversals.
           */
          LIST_INSERT_HEAD(&sc->sc_iflist, bif, bif_next);
  
          /* Set interface capabilities to the intersection set of all members */
          bridge_mutecaps(sc);
          bridge_linkcheck(sc);
  
          /* Place the interface into promiscuous mode */
          switch (ifs->if_type) {
                  case IFT_ETHER:
                  case IFT_L2VLAN:
                          BRIDGE_UNLOCK(sc);
                          error = ifpromisc(ifs, 1);
                          BRIDGE_LOCK(sc);
                          break;
          }
  
          if (error)
                  bridge_delete_member(sc, bif, 0);
          return (error);
  }
  
  static int
  bridge_ioctl_del(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif;
  
          bif = bridge_lookup_member(sc, req->ifbr_ifsname);
          if (bif == NULL)
                  return (ENOENT);
  
          bridge_delete_member(sc, bif, 0);
  
          return (0);
  }
  
  static int
  bridge_ioctl_gifflags(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif;
          struct bstp_port *bp;
  
          bif = bridge_lookup_member(sc, req->ifbr_ifsname);
          if (bif == NULL)
                  return (ENOENT);
  
          bp = &bif->bif_stp;
          req->ifbr_ifsflags = bif->bif_flags;
          req->ifbr_state = bp->bp_state;
          req->ifbr_priority = bp->bp_priority;
          req->ifbr_path_cost = bp->bp_path_cost;
          req->ifbr_portno = bif->bif_ifp->if_index & 0xfff;
          req->ifbr_proto = bp->bp_protover;
          req->ifbr_role = bp->bp_role;
          req->ifbr_stpflags = bp->bp_flags;
          req->ifbr_addrcnt = bif->bif_addrcnt;
          req->ifbr_addrmax = bif->bif_addrmax;
          req->ifbr_addrexceeded = bif->bif_addrexceeded;
  
          /* Copy STP state options as flags */
          if (bp->bp_operedge)
                  req->ifbr_ifsflags |= IFBIF_BSTP_EDGE;
          if (bp->bp_flags & BSTP_PORT_AUTOEDGE)
                  req->ifbr_ifsflags |= IFBIF_BSTP_AUTOEDGE;
          if (bp->bp_ptp_link)
                  req->ifbr_ifsflags |= IFBIF_BSTP_PTP;
          if (bp->bp_flags & BSTP_PORT_AUTOPTP)
                  req->ifbr_ifsflags |= IFBIF_BSTP_AUTOPTP;
          if (bp->bp_flags & BSTP_PORT_ADMEDGE)
                  req->ifbr_ifsflags |= IFBIF_BSTP_ADMEDGE;
          if (bp->bp_flags & BSTP_PORT_ADMCOST)
                  req->ifbr_ifsflags |= IFBIF_BSTP_ADMCOST;
          return (0);
  }
  
  static int
  bridge_ioctl_sifflags(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif;
          struct bstp_port *bp;
          int error;
  
          bif = bridge_lookup_member(sc, req->ifbr_ifsname);
          if (bif == NULL)
                  return (ENOENT);
          bp = &bif->bif_stp;
  
          if (req->ifbr_ifsflags & IFBIF_SPAN)
                  /* SPAN is readonly */
                  return (EINVAL);
  
          if (req->ifbr_ifsflags & IFBIF_STP) {
                  if ((bif->bif_flags & IFBIF_STP) == 0) {
                          error = bstp_enable(&bif->bif_stp);
                          if (error)
                                  return (error);
                  }
          } else {
                  if ((bif->bif_flags & IFBIF_STP) != 0)
                          bstp_disable(&bif->bif_stp);
          }
  
          /* Pass on STP flags */
          bstp_set_edge(bp, req->ifbr_ifsflags & IFBIF_BSTP_EDGE ? 1 : 0);
          bstp_set_autoedge(bp, req->ifbr_ifsflags & IFBIF_BSTP_AUTOEDGE ? 1 : 0);
          bstp_set_ptp(bp, req->ifbr_ifsflags & IFBIF_BSTP_PTP ? 1 : 0);
          bstp_set_autoptp(bp, req->ifbr_ifsflags & IFBIF_BSTP_AUTOPTP ? 1 : 0);
  
          /* Save the bits relating to the bridge */
          bif->bif_flags = req->ifbr_ifsflags & IFBIFMASK;
  
          return (0);
  }
  
  static int
  bridge_ioctl_scache(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          sc->sc_brtmax = param->ifbrp_csize;
          bridge_rttrim(sc);
  
          return (0);
  }
  
  static int
  bridge_ioctl_gcache(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          param->ifbrp_csize = sc->sc_brtmax;
  
          return (0);
  }
  
  static int
  bridge_ioctl_gifs(struct bridge_softc *sc, void *arg)
  {
          struct ifbifconf *bifc = arg;
          struct bridge_iflist *bif;
          struct ifbreq breq;
          char *buf, *outbuf;
          int count, buflen, len, error = 0;
  
          count = 0;
          LIST_FOREACH(bif, &sc->sc_iflist, bif_next)
                  count++;
          LIST_FOREACH(bif, &sc->sc_spanlist, bif_next)
                  count++;
  
          buflen = sizeof(breq) * count;
          if (bifc->ifbic_len == 0) {
                  bifc->ifbic_len = buflen;
                  return (0);
          }
          BRIDGE_UNLOCK(sc);
          outbuf = malloc(buflen, M_TEMP, M_WAITOK | M_ZERO);
          BRIDGE_LOCK(sc);
  
          count = 0;
          buf = outbuf;
          len = min(bifc->ifbic_len, buflen);
          bzero(&breq, sizeof(breq));
          LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                  if (len < sizeof(breq))
                          break;
  
                  strlcpy(breq.ifbr_ifsname, bif->bif_ifp->if_xname,
                      sizeof(breq.ifbr_ifsname));
                  /* Fill in the ifbreq structure */
                  error = bridge_ioctl_gifflags(sc, &breq);
                  if (error)
                          break;
                  memcpy(buf, &breq, sizeof(breq));
                  count++;
                  buf += sizeof(breq);
                  len -= sizeof(breq);
          }
          LIST_FOREACH(bif, &sc->sc_spanlist, bif_next) {
                  if (len < sizeof(breq))
                          break;
  
                  strlcpy(breq.ifbr_ifsname, bif->bif_ifp->if_xname,
                      sizeof(breq.ifbr_ifsname));
                  breq.ifbr_ifsflags = bif->bif_flags;
                  breq.ifbr_portno = bif->bif_ifp->if_index & 0xfff;
                  memcpy(buf, &breq, sizeof(breq));
                  count++;
                  buf += sizeof(breq);
                  len -= sizeof(breq);
          }
  
          BRIDGE_UNLOCK(sc);
          bifc->ifbic_len = sizeof(breq) * count;
          error = copyout(outbuf, bifc->ifbic_req, bifc->ifbic_len);
          BRIDGE_LOCK(sc);
          free(outbuf, M_TEMP);
          return (error);
  }
  
  static int
  bridge_ioctl_rts(struct bridge_softc *sc, void *arg)
  {
          struct ifbaconf *bac = arg;
          struct bridge_rtnode *brt;
          struct ifbareq bareq;
          char *buf, *outbuf;
          int count, buflen, len, error = 0;
  
          if (bac->ifbac_len == 0)
                  return (0);
  
          count = 0;
          LIST_FOREACH(brt, &sc->sc_rtlist, brt_list)
                  count++;
          buflen = sizeof(bareq) * count;
  
          BRIDGE_UNLOCK(sc);
          outbuf = malloc(buflen, M_TEMP, M_WAITOK | M_ZERO);
          BRIDGE_LOCK(sc);
  
          count = 0;
          buf = outbuf;
          len = min(bac->ifbac_len, buflen);
          bzero(&bareq, sizeof(bareq));
          LIST_FOREACH(brt, &sc->sc_rtlist, brt_list) {
                  if (len < sizeof(bareq))
                          goto out;
                  strlcpy(bareq.ifba_ifsname, brt->brt_ifp->if_xname,
                      sizeof(bareq.ifba_ifsname));
                  memcpy(bareq.ifba_dst, brt->brt_addr, sizeof(brt->brt_addr));
                  bareq.ifba_vlan = brt->brt_vlan;
                  if ((brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC &&
                                  time_uptime < brt->brt_expire)
                          bareq.ifba_expire = brt->brt_expire - time_uptime;
                  else
                          bareq.ifba_expire = 0;
                  bareq.ifba_flags = brt->brt_flags;
  
                  memcpy(buf, &bareq, sizeof(bareq));
                  count++;
                  buf += sizeof(bareq);
                  len -= sizeof(bareq);
          }
  out:
          BRIDGE_UNLOCK(sc);
          bac->ifbac_len = sizeof(bareq) * count;
          error = copyout(outbuf, bac->ifbac_req, bac->ifbac_len);
          BRIDGE_LOCK(sc);
          free(outbuf, M_TEMP);
          return (error);
  }
  
  static int
  bridge_ioctl_saddr(struct bridge_softc *sc, void *arg)
  {
          struct ifbareq *req = arg;
          struct bridge_iflist *bif;
          int error;
  
          bif = bridge_lookup_member(sc, req->ifba_ifsname);
          if (bif == NULL)
                  return (ENOENT);
  
          error = bridge_rtupdate(sc, req->ifba_dst, req->ifba_vlan, bif, 1,
              req->ifba_flags);
  
          return (error);
  }
  
  static int
  bridge_ioctl_sto(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          sc->sc_brttimeout = param->ifbrp_ctime;
          return (0);
  }
  
  static int
  bridge_ioctl_gto(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          param->ifbrp_ctime = sc->sc_brttimeout;
          return (0);
  }
  
  static int
  bridge_ioctl_daddr(struct bridge_softc *sc, void *arg)
  {
          struct ifbareq *req = arg;
  
          return (bridge_rtdaddr(sc, req->ifba_dst, req->ifba_vlan));
  }
  
  static int
  bridge_ioctl_flush(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
  
          bridge_rtflush(sc, req->ifbr_ifsflags);
          return (0);
  }
  
  static int
  bridge_ioctl_gpri(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
          struct bstp_state *bs = &sc->sc_stp;
  
          param->ifbrp_prio = bs->bs_bridge_priority;
          return (0);
  }
  
  static int
  bridge_ioctl_spri(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          return (bstp_set_priority(&sc->sc_stp, param->ifbrp_prio));
  }
  
  static int
  bridge_ioctl_ght(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
          struct bstp_state *bs = &sc->sc_stp;
  
          param->ifbrp_hellotime = bs->bs_bridge_htime >> 8;
          return (0);
  }
  
  static int
  bridge_ioctl_sht(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          return (bstp_set_htime(&sc->sc_stp, param->ifbrp_hellotime));
  }
  
  static int
  bridge_ioctl_gfd(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
          struct bstp_state *bs = &sc->sc_stp;
  
          param->ifbrp_fwddelay = bs->bs_bridge_fdelay >> 8;
          return (0);
  }
  
  static int
  bridge_ioctl_sfd(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          return (bstp_set_fdelay(&sc->sc_stp, param->ifbrp_fwddelay));
  }
  
  static int
  bridge_ioctl_gma(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
          struct bstp_state *bs = &sc->sc_stp;
  
          param->ifbrp_maxage = bs->bs_bridge_max_age >> 8;
          return (0);
  }
  
  static int
  bridge_ioctl_sma(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          return (bstp_set_maxage(&sc->sc_stp, param->ifbrp_maxage));
  }
  
  static int
  bridge_ioctl_sifprio(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif;
  
          bif = bridge_lookup_member(sc, req->ifbr_ifsname);
          if (bif == NULL)
                  return (ENOENT);
  
          return (bstp_set_port_priority(&bif->bif_stp, req->ifbr_priority));
  }
  
  static int
  bridge_ioctl_sifcost(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif;
  
          bif = bridge_lookup_member(sc, req->ifbr_ifsname);
          if (bif == NULL)
                  return (ENOENT);
  
          return (bstp_set_path_cost(&bif->bif_stp, req->ifbr_path_cost));
  }
  
  static int
  bridge_ioctl_sifmaxaddr(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif;
  
          bif = bridge_lookup_member(sc, req->ifbr_ifsname);
          if (bif == NULL)
                  return (ENOENT);
  
          bif->bif_addrmax = req->ifbr_addrmax;
          return (0);
  }
  
  static int
  bridge_ioctl_addspan(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif = NULL;
          struct ifnet *ifs;
  
          ifs = ifunit(req->ifbr_ifsname);
          if (ifs == NULL)
                  return (ENOENT);
  
          LIST_FOREACH(bif, &sc->sc_spanlist, bif_next)
                  if (ifs == bif->bif_ifp)
                          return (EBUSY);
  
          if (ifs->if_bridge != NULL)
                  return (EBUSY);
  
          switch (ifs->if_type) {
                  case IFT_ETHER:
                  case IFT_GIF:
                  case IFT_L2VLAN:
                          break;
                  default:
                          return (EINVAL);
          }
  
          bif = malloc(sizeof(*bif), M_DEVBUF, M_NOWAIT|M_ZERO);
          if (bif == NULL)
                  return (ENOMEM);
  
          bif->bif_ifp = ifs;
          bif->bif_flags = IFBIF_SPAN;
  
          LIST_INSERT_HEAD(&sc->sc_spanlist, bif, bif_next);
  
          return (0);
  }
  
  static int
  bridge_ioctl_delspan(struct bridge_softc *sc, void *arg)
  {
          struct ifbreq *req = arg;
          struct bridge_iflist *bif;
          struct ifnet *ifs;
  
          ifs = ifunit(req->ifbr_ifsname);
          if (ifs == NULL)
                  return (ENOENT);
  
          LIST_FOREACH(bif, &sc->sc_spanlist, bif_next)
                  if (ifs == bif->bif_ifp)
                          break;
  
          if (bif == NULL)
                  return (ENOENT);
  
          bridge_delete_span(sc, bif);
  
          return (0);
  }
  
  static int
  bridge_ioctl_gbparam(struct bridge_softc *sc, void *arg)
  {
          struct ifbropreq *req = arg;
          struct bstp_state *bs = &sc->sc_stp;
          struct bstp_port *root_port;
  
          req->ifbop_maxage = bs->bs_bridge_max_age >> 8;
          req->ifbop_hellotime = bs->bs_bridge_htime >> 8;
          req->ifbop_fwddelay = bs->bs_bridge_fdelay >> 8;
  
          root_port = bs->bs_root_port;
          if (root_port == NULL)
                  req->ifbop_root_port = 0;
          else
                  req->ifbop_root_port = root_port->bp_ifp->if_index;
  
          req->ifbop_holdcount = bs->bs_txholdcount;
          req->ifbop_priority = bs->bs_bridge_priority;
          req->ifbop_protocol = bs->bs_protover;
          req->ifbop_root_path_cost = bs->bs_root_pv.pv_cost;
          req->ifbop_bridgeid = bs->bs_bridge_pv.pv_dbridge_id;
          req->ifbop_designated_root = bs->bs_root_pv.pv_root_id;
          req->ifbop_designated_bridge = bs->bs_root_pv.pv_dbridge_id;
          req->ifbop_last_tc_time.tv_sec = bs->bs_last_tc_time.tv_sec;
          req->ifbop_last_tc_time.tv_usec = bs->bs_last_tc_time.tv_usec;
  
          return (0);
  }
  
  static int
  bridge_ioctl_grte(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          param->ifbrp_cexceeded = sc->sc_brtexceeded;
          return (0);
  }
  
  static int
  bridge_ioctl_gifsstp(struct bridge_softc *sc, void *arg)
  {
          struct ifbpstpconf *bifstp = arg;
          struct bridge_iflist *bif;
          struct bstp_port *bp;
          struct ifbpstpreq bpreq;
          char *buf, *outbuf;
          int count, buflen, len, error = 0;
  
          count = 0;
          LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                  if ((bif->bif_flags & IFBIF_STP) != 0)
                          count++;
          }
  
          buflen = sizeof(bpreq) * count;
          if (bifstp->ifbpstp_len == 0) {
                  bifstp->ifbpstp_len = buflen;
                  return (0);
          }
  
          BRIDGE_UNLOCK(sc);
          outbuf = malloc(buflen, M_TEMP, M_WAITOK | M_ZERO);
          BRIDGE_LOCK(sc);
  
          count = 0;
          buf = outbuf;
          len = min(bifstp->ifbpstp_len, buflen);
          bzero(&bpreq, sizeof(bpreq));
          LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                  if (len < sizeof(bpreq))
                          break;
  
                  if ((bif->bif_flags & IFBIF_STP) == 0)
                          continue;
  
                  bp = &bif->bif_stp;
                  bpreq.ifbp_portno = bif->bif_ifp->if_index & 0xfff;
                  bpreq.ifbp_fwd_trans = bp->bp_forward_transitions;
                  bpreq.ifbp_design_cost = bp->bp_desg_pv.pv_cost;
                  bpreq.ifbp_design_port = bp->bp_desg_pv.pv_port_id;
                  bpreq.ifbp_design_bridge = bp->bp_desg_pv.pv_dbridge_id;
                  bpreq.ifbp_design_root = bp->bp_desg_pv.pv_root_id;
  
                  memcpy(buf, &bpreq, sizeof(bpreq));
                  count++;
                  buf += sizeof(bpreq);
                  len -= sizeof(bpreq);
          }
  
          BRIDGE_UNLOCK(sc);
          bifstp->ifbpstp_len = sizeof(bpreq) * count;
          error = copyout(outbuf, bifstp->ifbpstp_req, bifstp->ifbpstp_len);
          BRIDGE_LOCK(sc);
          free(outbuf, M_TEMP);
          return (error);
  }
  
  static int
  bridge_ioctl_sproto(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          return (bstp_set_protocol(&sc->sc_stp, param->ifbrp_proto));
  }
  
  static int
  bridge_ioctl_stxhc(struct bridge_softc *sc, void *arg)
  {
          struct ifbrparam *param = arg;
  
          return (bstp_set_holdcount(&sc->sc_stp, param->ifbrp_txhc));
  }
  
  /*
   * bridge_ifdetach:
   *
   *      Detach an interface from a bridge.  Called when a member
   *      interface is detaching.
   */
  static void
  bridge_ifdetach(void *arg __unused, struct ifnet *ifp)
  {
          struct bridge_softc *sc = ifp->if_bridge;
          struct bridge_iflist *bif;
  
          if (ifp->if_flags & IFF_RENAMING)
                  return;
  
          /* Check if the interface is a bridge member */
          if (sc != NULL) {
                  BRIDGE_LOCK(sc);
  
                  bif = bridge_lookup_member_if(sc, ifp);
                  if (bif != NULL)
                          bridge_delete_member(sc, bif, 1);
  
                  BRIDGE_UNLOCK(sc);
                  return;
          }
  
          /* Check if the interface is a span port */
          mtx_lock(&bridge_list_mtx);
          LIST_FOREACH(sc, &bridge_list, sc_list) {
                  BRIDGE_LOCK(sc);
                  LIST_FOREACH(bif, &sc->sc_spanlist, bif_next)
                          if (ifp == bif->bif_ifp) {
                                  bridge_delete_span(sc, bif);
                                  break;
                          }
  
                  BRIDGE_UNLOCK(sc);
          }
          mtx_unlock(&bridge_list_mtx);
  }
  
  /*
   * bridge_init:
   *
   *      Initialize a bridge interface.
   */
  static void
  bridge_init(void *xsc)
  {
          struct bridge_softc *sc = (struct bridge_softc *)xsc;
          struct ifnet *ifp = sc->sc_ifp;
  
          if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                  return;
  
          BRIDGE_LOCK(sc);
          callout_reset(&sc->sc_brcallout, bridge_rtable_prune_period * hz,
              bridge_timer, sc);
  
          ifp->if_drv_flags |= IFF_DRV_RUNNING;
          bstp_init(&sc->sc_stp);         /* Initialize Spanning Tree */
  
          BRIDGE_UNLOCK(sc);
  }
  
  /*
   * bridge_stop:
   *
   *      Stop the bridge interface.
   */
  static void
  bridge_stop(struct ifnet *ifp, int disable)
  {
          struct bridge_softc *sc = ifp->if_softc;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
                  return;
  
          callout_stop(&sc->sc_brcallout);
          bstp_stop(&sc->sc_stp);
  
          bridge_rtflush(sc, IFBF_FLUSHDYN);
  
          ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
  }
  
  /*
   * bridge_enqueue:
   *
   *      Enqueue a packet on a bridge member interface.
   *
   */
  static int
  bridge_enqueue(struct bridge_softc *sc, struct ifnet *dst_ifp, struct mbuf *m)
  {
          int len, err = 0;
          short mflags;
          struct mbuf *m0;
  
          /* We may be sending a fragment so traverse the mbuf */
          for (; m; m = m0) {
                  m0 = m->m_nextpkt;
                  m->m_nextpkt = NULL;
                  len = m->m_pkthdr.len;
                  mflags = m->m_flags;
  
                  /*
                   * If underlying interface can not do VLAN tag insertion itself
                   * then attach a packet tag that holds it.
                   */
                  if ((m->m_flags & M_VLANTAG) &&
                      (dst_ifp->if_capenable & IFCAP_VLAN_HWTAGGING) == 0) {
                          m = ether_vlanencap(m, m->m_pkthdr.ether_vtag);
                          if (m == NULL) {
                                  if_printf(dst_ifp,
                                      "unable to prepend VLAN header\n");
                                  dst_ifp->if_oerrors++;
                                  continue;
                          }
                          m->m_flags &= ~M_VLANTAG;
                  }
  
                  M_ASSERTPKTHDR(m); /* We shouldn't transmit mbuf without pkthdr */
                  if ((err = dst_ifp->if_transmit(dst_ifp, m))) {
                          m_freem(m0);
                          sc->sc_ifp->if_oerrors++;
                          break;
                  }
  
                  sc->sc_ifp->if_opackets++;
                  sc->sc_ifp->if_obytes += len;
                  if (mflags & M_MCAST)
                          sc->sc_ifp->if_omcasts++;
          }
  
          return (err);
  }
  
  /*
   * bridge_dummynet:
   *
   *      Receive a queued packet from dummynet and pass it on to the output
   *      interface.
   *
   *      The mbuf has the Ethernet header already attached.
   */
  static void
  bridge_dummynet(struct mbuf *m, struct ifnet *ifp)
  {
          struct bridge_softc *sc;
  
          sc = ifp->if_bridge;
  
          /*
           * The packet didnt originate from a member interface. This should only
           * ever happen if a member interface is removed while packets are
           * queued for it.
           */
          if (sc == NULL) {
                  m_freem(m);
                  return;
          }
  
          if (PFIL_HOOKED(&V_inet_pfil_hook)
  #ifdef INET6
              || PFIL_HOOKED(&V_inet6_pfil_hook)
  #endif
              ) {
                  if (bridge_pfil(&m, sc->sc_ifp, ifp, PFIL_OUT) != 0)
                          return;
                  if (m == NULL)
                          return;
          }
  
          bridge_enqueue(sc, ifp, m);
  }
  
  /*
   * bridge_output:
   *
   *      Send output from a bridge member interface.  This
   *      performs the bridging function for locally originated
   *      packets.
   *
   *      The mbuf has the Ethernet header already attached.  We must
   *      enqueue or free the mbuf before returning.
   */
  static int
  bridge_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
      struct rtentry *rt)
  {
          struct ether_header *eh;
          struct ifnet *dst_if;
          struct bridge_softc *sc;
          uint16_t vlan;
  
          if (m->m_len < ETHER_HDR_LEN) {
                  m = m_pullup(m, ETHER_HDR_LEN);
                  if (m == NULL)
                          return (0);
          }
  
          eh = mtod(m, struct ether_header *);
          sc = ifp->if_bridge;
          vlan = VLANTAGOF(m);
  
          BRIDGE_LOCK(sc);
  
          /*
           * If bridge is down, but the original output interface is up,
           * go ahead and send out that interface.  Otherwise, the packet
           * is dropped below.
           */
          if ((sc->sc_ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
                  dst_if = ifp;
                  goto sendunicast;
          }
  
          /*
           * If the packet is a multicast, or we don't know a better way to
           * get there, send to all interfaces.
           */
          if (ETHER_IS_MULTICAST(eh->ether_dhost))
                  dst_if = NULL;
          else
                  dst_if = bridge_rtlookup(sc, eh->ether_dhost, vlan);
          if (dst_if == NULL) {
                  struct bridge_iflist *bif;
                  struct mbuf *mc;
                  int error = 0, used = 0;
  
                  bridge_span(sc, m);
  
                  BRIDGE_LOCK2REF(sc, error);
                  if (error) {
                          m_freem(m);
                          return (0);
                  }
  
                  LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                          dst_if = bif->bif_ifp;
  
                          if (dst_if->if_type == IFT_GIF)
                                  continue;
                          if ((dst_if->if_drv_flags & IFF_DRV_RUNNING) == 0)
                                  continue;
  
                          /*
                           * If this is not the original output interface,
                           * and the interface is participating in spanning
                           * tree, make sure the port is in a state that
                           * allows forwarding.
                           */
                          if (dst_if != ifp && (bif->bif_flags & IFBIF_STP) &&
                              bif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING)
                                  continue;
  
                          if (LIST_NEXT(bif, bif_next) == NULL) {
                                  used = 1;
                                  mc = m;
                          } else {
                                  mc = m_copypacket(m, M_NOWAIT);
                                  if (mc == NULL) {
                                          sc->sc_ifp->if_oerrors++;
                                          continue;
                                  }
                          }
  
                          bridge_enqueue(sc, dst_if, mc);
                  }
                  if (used == 0)
                          m_freem(m);
                  BRIDGE_UNREF(sc);
                  return (0);
          }
  
  sendunicast:
          /*
           * XXX Spanning tree consideration here?
           */
  
          bridge_span(sc, m);
          if ((dst_if->if_drv_flags & IFF_DRV_RUNNING) == 0) {
                  m_freem(m);
                  BRIDGE_UNLOCK(sc);
                  return (0);
          }
  
          BRIDGE_UNLOCK(sc);
          bridge_enqueue(sc, dst_if, m);
          return (0);
  }
  
  /*
   * bridge_transmit:
   *
   *      Do output on a bridge.
   *
   */
  static int
  bridge_transmit(struct ifnet *ifp, struct mbuf *m)
  {
          struct bridge_softc *sc;
          struct ether_header *eh;
          struct ifnet *dst_if;
          int error = 0;
  
          sc = ifp->if_softc;
  
          ETHER_BPF_MTAP(ifp, m);
  
          eh = mtod(m, struct ether_header *);
  
          BRIDGE_LOCK(sc);
          if (((m->m_flags & (M_BCAST|M_MCAST)) == 0) &&
              (dst_if = bridge_rtlookup(sc, eh->ether_dhost, 1)) != NULL) {
                  BRIDGE_UNLOCK(sc);
                  error = bridge_enqueue(sc, dst_if, m);
          } else
                  bridge_broadcast(sc, ifp, m, 0);
  
          return (error);
  }
  
  /*
   * The ifp->if_qflush entry point for if_bridge(4) is no-op.
   */
  static void
  bridge_qflush(struct ifnet *ifp __unused)
  {
  }
  
  /*
   * bridge_forward:
   *
   *      The forwarding function of the bridge.
   *
   *      NOTE: Releases the lock on return.
   */
  static void
  bridge_forward(struct bridge_softc *sc, struct bridge_iflist *sbif,
      struct mbuf *m)
  {
          struct bridge_iflist *dbif;
          struct ifnet *src_if, *dst_if, *ifp;
          struct ether_header *eh;
          uint16_t vlan;
          uint8_t *dst;
          int error;
  
          src_if = m->m_pkthdr.rcvif;
          ifp = sc->sc_ifp;
  
          ifp->if_ipackets++;
          ifp->if_ibytes += m->m_pkthdr.len;
          vlan = VLANTAGOF(m);
  
          if ((sbif->bif_flags & IFBIF_STP) &&
              sbif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING)
                  goto drop;
  
          eh = mtod(m, struct ether_header *);
          dst = eh->ether_dhost;
  
          /* If the interface is learning, record the address. */
          if (sbif->bif_flags & IFBIF_LEARNING) {
                  error = bridge_rtupdate(sc, eh->ether_shost, vlan,
                      sbif, 0, IFBAF_DYNAMIC);
                  /*
                   * If the interface has addresses limits then deny any source
                   * that is not in the cache.
                   */
                  if (error && sbif->bif_addrmax)
                          goto drop;
          }
  
          if ((sbif->bif_flags & IFBIF_STP) != 0 &&
              sbif->bif_stp.bp_state == BSTP_IFSTATE_LEARNING)
                  goto drop;
  
          /*
           * At this point, the port either doesn't participate
           * in spanning tree or it is in the forwarding state.
           */
  
          /*
           * If the packet is unicast, destined for someone on
           * "this" side of the bridge, drop it.
           */
          if ((m->m_flags & (M_BCAST|M_MCAST)) == 0) {
                  dst_if = bridge_rtlookup(sc, dst, vlan);
                  if (src_if == dst_if)
                          goto drop;
          } else {
                  /*
                   * Check if its a reserved multicast address, any address
                   * listed in 802.1D section 7.12.6 may not be forwarded by the
                   * bridge.
                   * This is currently 01-80-C2-00-00-00 to 01-80-C2-00-00-0F
                   */
                  if (dst[0] == 0x01 && dst[1] == 0x80 &&
                      dst[2] == 0xc2 && dst[3] == 0x00 &&
                      dst[4] == 0x00 && dst[5] <= 0x0f)
                          goto drop;
  
                  /* ...forward it to all interfaces. */
                  ifp->if_imcasts++;
                  dst_if = NULL;
          }
  
          /*
           * If we have a destination interface which is a member of our bridge,
           * OR this is a unicast packet, push it through the bpf(4) machinery.
           * For broadcast or multicast packets, don't bother because it will
           * be reinjected into ether_input. We do this before we pass the packets
           * through the pfil(9) framework, as it is possible that pfil(9) will
           * drop the packet, or possibly modify it, making it difficult to debug
           * firewall issues on the bridge.
           */
          if (dst_if != NULL || (m->m_flags & (M_BCAST | M_MCAST)) == 0)
                  ETHER_BPF_MTAP(ifp, m);
  
          /* run the packet filter */
          if (PFIL_HOOKED(&V_inet_pfil_hook)
  #ifdef INET6
              || PFIL_HOOKED(&V_inet6_pfil_hook)
  #endif
              ) {
                  BRIDGE_UNLOCK(sc);
                  if (bridge_pfil(&m, ifp, src_if, PFIL_IN) != 0)
                          return;
                  if (m == NULL)
                          return;
                  BRIDGE_LOCK(sc);
          }
  
          if (dst_if == NULL) {
                  bridge_broadcast(sc, src_if, m, 1);
                  return;
          }
  
          /*
           * At this point, we're dealing with a unicast frame
           * going to a different interface.
           */
          if ((dst_if->if_drv_flags & IFF_DRV_RUNNING) == 0)
                  goto drop;
  
          dbif = bridge_lookup_member_if(sc, dst_if);
          if (dbif == NULL)
                  /* Not a member of the bridge (anymore?) */
                  goto drop;
  
          /* Private segments can not talk to each other */
          if (sbif->bif_flags & dbif->bif_flags & IFBIF_PRIVATE)
                  goto drop;
  
          if ((dbif->bif_flags & IFBIF_STP) &&
              dbif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING)
                  goto drop;
  
          BRIDGE_UNLOCK(sc);
  
          if (PFIL_HOOKED(&V_inet_pfil_hook)
  #ifdef INET6
              || PFIL_HOOKED(&V_inet6_pfil_hook)
  #endif
              ) {
                  if (bridge_pfil(&m, ifp, dst_if, PFIL_OUT) != 0)
                          return;
                  if (m == NULL)
                          return;
          }
  
          bridge_enqueue(sc, dst_if, m);
          return;
  
  drop:
          BRIDGE_UNLOCK(sc);
          m_freem(m);
  }
  
  /*
   * bridge_input:
   *
   *      Receive input from a member interface.  Queue the packet for
   *      bridging if it is not for us.
   */
  static struct mbuf *
  bridge_input(struct ifnet *ifp, struct mbuf *m)
  {
          struct bridge_softc *sc = ifp->if_bridge;
          struct bridge_iflist *bif, *bif2;
          struct ifnet *bifp;
          struct ether_header *eh;
          struct mbuf *mc, *mc2;
          uint16_t vlan;
          int error;
  
          if ((sc->sc_ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
                  return (m);
  
          bifp = sc->sc_ifp;
          vlan = VLANTAGOF(m);
  
          /*
           * Implement support for bridge monitoring. If this flag has been
           * set on this interface, discard the packet once we push it through
           * the bpf(4) machinery, but before we do, increment the byte and
           * packet counters associated with this interface.
           */
          if ((bifp->if_flags & IFF_MONITOR) != 0) {
                  m->m_pkthdr.rcvif  = bifp;
                  ETHER_BPF_MTAP(bifp, m);
                  bifp->if_ipackets++;
                  bifp->if_ibytes += m->m_pkthdr.len;
                  m_freem(m);
                  return (NULL);
          }
          BRIDGE_LOCK(sc);
          bif = bridge_lookup_member_if(sc, ifp);
          if (bif == NULL) {
                  BRIDGE_UNLOCK(sc);
                  return (m);
          }
  
          eh = mtod(m, struct ether_header *);
  
          bridge_span(sc, m);
  
          if (m->m_flags & (M_BCAST|M_MCAST)) {
                  /* Tap off 802.1D packets; they do not get forwarded. */
                  if (memcmp(eh->ether_dhost, bstp_etheraddr,
                      ETHER_ADDR_LEN) == 0) {
                          bstp_input(&bif->bif_stp, ifp, m); /* consumes mbuf */
                          BRIDGE_UNLOCK(sc);
                          return (NULL);
                  }
  
                  if ((bif->bif_flags & IFBIF_STP) &&
                      bif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING) {
                          BRIDGE_UNLOCK(sc);
                          return (m);
                  }
  
                  /*
                   * Make a deep copy of the packet and enqueue the copy
                   * for bridge processing; return the original packet for
                   * local processing.
                   */
                  mc = m_dup(m, M_NOWAIT);
                  if (mc == NULL) {
                          BRIDGE_UNLOCK(sc);
                          return (m);
                  }
  
                  /* Perform the bridge forwarding function with the copy. */
                  bridge_forward(sc, bif, mc);
  
                  /*
                   * Reinject the mbuf as arriving on the bridge so we have a
                   * chance at claiming multicast packets. We can not loop back
                   * here from ether_input as a bridge is never a member of a
                   * bridge.
                   */
                  KASSERT(bifp->if_bridge == NULL,
                      ("loop created in bridge_input"));
                  mc2 = m_dup(m, M_NOWAIT);
                  if (mc2 != NULL) {
                          /* Keep the layer3 header aligned */
                          int i = min(mc2->m_pkthdr.len, max_protohdr);
                          mc2 = m_copyup(mc2, i, ETHER_ALIGN);
                  }
                  if (mc2 != NULL) {
                          mc2->m_pkthdr.rcvif = bifp;
                          (*bifp->if_input)(bifp, mc2);
                  }
  
                  /* Return the original packet for local processing. */
                  return (m);
          }
  
          if ((bif->bif_flags & IFBIF_STP) &&
              bif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING) {
                  BRIDGE_UNLOCK(sc);
                  return (m);
          }
  
  #if (defined(INET) || defined(INET6))
  #   define OR_CARP_CHECK_WE_ARE_DST(iface) \
          || ((iface)->if_carp \
              && (*carp_forus_p)((iface), eh->ether_dhost))
  #   define OR_CARP_CHECK_WE_ARE_SRC(iface) \
          || ((iface)->if_carp \
              && (*carp_forus_p)((iface), eh->ether_shost))
  #else
  #   define OR_CARP_CHECK_WE_ARE_DST(iface)
  #   define OR_CARP_CHECK_WE_ARE_SRC(iface)
  #endif
  
  #ifdef INET6
  #   define OR_PFIL_HOOKED_INET6 \
          || PFIL_HOOKED(&V_inet6_pfil_hook)
  #else
  #   define OR_PFIL_HOOKED_INET6
  #endif
  
  #define GRAB_OUR_PACKETS(iface) \
          if ((iface)->if_type == IFT_GIF) \
                  continue; \
          /* It is destined for us. */ \
          if (memcmp(IF_LLADDR((iface)), eh->ether_dhost,  ETHER_ADDR_LEN) == 0 \
              OR_CARP_CHECK_WE_ARE_DST((iface))                           \
              ) {                                                         \
                  if ((iface)->if_type == IFT_BRIDGE) {                   \
                          ETHER_BPF_MTAP(iface, m);                       \
                          iface->if_ipackets++;                           \
                          iface->if_ibytes += m->m_pkthdr.len;            \
                          /* Filter on the physical interface. */         \
                          if (pfil_local_phys &&                          \
                              (PFIL_HOOKED(&V_inet_pfil_hook)             \
                               OR_PFIL_HOOKED_INET6)) {                   \
                                  if (bridge_pfil(&m, NULL, ifp,          \
                                      PFIL_IN) != 0 || m == NULL) {       \
                                          BRIDGE_UNLOCK(sc);              \
                                          return (NULL);                  \
                                  }                                       \
                                  eh = mtod(m, struct ether_header *);    \
                          }                                               \
                  }                                                       \
                  if (bif->bif_flags & IFBIF_LEARNING) {                  \
                          error = bridge_rtupdate(sc, eh->ether_shost,    \
                              vlan, bif, 0, IFBAF_DYNAMIC);               \
                          if (error && bif->bif_addrmax) {                \
                                  BRIDGE_UNLOCK(sc);                      \
                                  m_freem(m);                             \
                                  return (NULL);                          \
                          }                                               \
                  }                                                       \
                  m->m_pkthdr.rcvif = iface;                              \
                  BRIDGE_UNLOCK(sc);                                      \
                  return (m);                                             \
          }                                                               \
                                                                          \
          /* We just received a packet that we sent out. */               \
          if (memcmp(IF_LLADDR((iface)), eh->ether_shost, ETHER_ADDR_LEN) == 0 \
              OR_CARP_CHECK_WE_ARE_SRC((iface))                   \
              ) {                                                         \
                  BRIDGE_UNLOCK(sc);                                      \
                  m_freem(m);                                             \
                  return (NULL);                                          \
          }
  
          /*
           * Unicast.  Make sure it's not for the bridge.
           */
          do { GRAB_OUR_PACKETS(bifp) } while (0);
  
          /*
           * Give a chance for ifp at first priority. This will help when the
           * packet comes through the interface like VLAN's with the same MACs
           * on several interfaces from the same bridge. This also will save
           * some CPU cycles in case the destination interface and the input
           * interface (eq ifp) are the same.
           */
          do { GRAB_OUR_PACKETS(ifp) } while (0);
  
          /* Now check the all bridge members. */
          LIST_FOREACH(bif2, &sc->sc_iflist, bif_next) {
                  GRAB_OUR_PACKETS(bif2->bif_ifp)
          }
  
  #undef OR_CARP_CHECK_WE_ARE_DST
  #undef OR_CARP_CHECK_WE_ARE_SRC
  #undef OR_PFIL_HOOKED_INET6
  #undef GRAB_OUR_PACKETS
  
          /* Perform the bridge forwarding function. */
          bridge_forward(sc, bif, m);
  
          return (NULL);
  }
  
  /*
   * bridge_broadcast:
   *
   *      Send a frame to all interfaces that are members of
   *      the bridge, except for the one on which the packet
   *      arrived.
   *
   *      NOTE: Releases the lock on return.
   */
  static void
  bridge_broadcast(struct bridge_softc *sc, struct ifnet *src_if,
      struct mbuf *m, int runfilt)
  {
          struct bridge_iflist *dbif, *sbif;
          struct mbuf *mc;
          struct ifnet *dst_if;
          int error = 0, used = 0, i;
  
          sbif = bridge_lookup_member_if(sc, src_if);
  
          BRIDGE_LOCK2REF(sc, error);
          if (error) {
                  m_freem(m);
                  return;
          }
  
          /* Filter on the bridge interface before broadcasting */
          if (runfilt && (PFIL_HOOKED(&V_inet_pfil_hook)
  #ifdef INET6
              || PFIL_HOOKED(&V_inet6_pfil_hook)
  #endif
              )) {
                  if (bridge_pfil(&m, sc->sc_ifp, NULL, PFIL_OUT) != 0)
                          goto out;
                  if (m == NULL)
                          goto out;
          }
  
          LIST_FOREACH(dbif, &sc->sc_iflist, bif_next) {
                  dst_if = dbif->bif_ifp;
                  if (dst_if == src_if)
                          continue;
  
                  /* Private segments can not talk to each other */
                  if (sbif && (sbif->bif_flags & dbif->bif_flags & IFBIF_PRIVATE))
                          continue;
  
                  if ((dbif->bif_flags & IFBIF_STP) &&
                      dbif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING)
                          continue;
  
                  if ((dbif->bif_flags & IFBIF_DISCOVER) == 0 &&
                      (m->m_flags & (M_BCAST|M_MCAST)) == 0)
                          continue;
  
                  if ((dst_if->if_drv_flags & IFF_DRV_RUNNING) == 0)
                          continue;
  
                  if (LIST_NEXT(dbif, bif_next) == NULL) {
                          mc = m;
                          used = 1;
                  } else {
                          mc = m_dup(m, M_NOWAIT);
                          if (mc == NULL) {
                                  sc->sc_ifp->if_oerrors++;
                                  continue;
                          }
                  }
  
                  /*
                   * Filter on the output interface. Pass a NULL bridge interface
                   * pointer so we do not redundantly filter on the bridge for
                   * each interface we broadcast on.
                   */
                  if (runfilt && (PFIL_HOOKED(&V_inet_pfil_hook)
  #ifdef INET6
                      || PFIL_HOOKED(&V_inet6_pfil_hook)
  #endif
                      )) {
                          if (used == 0) {
                                  /* Keep the layer3 header aligned */
                                  i = min(mc->m_pkthdr.len, max_protohdr);
                                  mc = m_copyup(mc, i, ETHER_ALIGN);
                                  if (mc == NULL) {
                                          sc->sc_ifp->if_oerrors++;
                                          continue;
                                  }
                          }
                          if (bridge_pfil(&mc, NULL, dst_if, PFIL_OUT) != 0)
                                  continue;
                          if (mc == NULL)
                                  continue;
                  }
  
                  bridge_enqueue(sc, dst_if, mc);
          }
          if (used == 0)
                  m_freem(m);
  
  out:
          BRIDGE_UNREF(sc);
  }
  
  /*
   * bridge_span:
   *
   *      Duplicate a packet out one or more interfaces that are in span mode,
   *      the original mbuf is unmodified.
   */
  static void
  bridge_span(struct bridge_softc *sc, struct mbuf *m)
  {
          struct bridge_iflist *bif;
          struct ifnet *dst_if;
          struct mbuf *mc;
  
          if (LIST_EMPTY(&sc->sc_spanlist))
                  return;
  
          LIST_FOREACH(bif, &sc->sc_spanlist, bif_next) {
                  dst_if = bif->bif_ifp;
  
                  if ((dst_if->if_drv_flags & IFF_DRV_RUNNING) == 0)
                          continue;
  
                  mc = m_copypacket(m, M_NOWAIT);
                  if (mc == NULL) {
                          sc->sc_ifp->if_oerrors++;
                          continue;
                  }
  
                  bridge_enqueue(sc, dst_if, mc);
          }
  }
  
  /*
   * bridge_rtupdate:
   *
   *      Add a bridge routing entry.
   */
  static int
  bridge_rtupdate(struct bridge_softc *sc, const uint8_t *dst, uint16_t vlan,
      struct bridge_iflist *bif, int setflags, uint8_t flags)
  {
          struct bridge_rtnode *brt;
          int error;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          /* Check the source address is valid and not multicast. */
          if (ETHER_IS_MULTICAST(dst) ||
              (dst[0] == 0 && dst[1] == 0 && dst[2] == 0 &&
               dst[3] == 0 && dst[4] == 0 && dst[5] == 0) != 0)
                  return (EINVAL);
  
          /* 802.1p frames map to vlan 1 */
          if (vlan == 0)
                  vlan = 1;
  
          /*
           * A route for this destination might already exist.  If so,
           * update it, otherwise create a new one.
           */
          if ((brt = bridge_rtnode_lookup(sc, dst, vlan)) == NULL) {
                  if (sc->sc_brtcnt >= sc->sc_brtmax) {
                          sc->sc_brtexceeded++;
                          return (ENOSPC);
                  }
                  /* Check per interface address limits (if enabled) */
                  if (bif->bif_addrmax && bif->bif_addrcnt >= bif->bif_addrmax) {
                          bif->bif_addrexceeded++;
                          return (ENOSPC);
                  }
  
                  /*
                   * Allocate a new bridge forwarding node, and
                   * initialize the expiration time and Ethernet
                   * address.
                   */
                  brt = uma_zalloc(bridge_rtnode_zone, M_NOWAIT | M_ZERO);
                  if (brt == NULL)
                          return (ENOMEM);
  
                  if (bif->bif_flags & IFBIF_STICKY)
                          brt->brt_flags = IFBAF_STICKY;
                  else
                          brt->brt_flags = IFBAF_DYNAMIC;
  
                  memcpy(brt->brt_addr, dst, ETHER_ADDR_LEN);
                  brt->brt_vlan = vlan;
  
                  if ((error = bridge_rtnode_insert(sc, brt)) != 0) {
                          uma_zfree(bridge_rtnode_zone, brt);
                          return (error);
                  }
                  brt->brt_dst = bif;
                  bif->bif_addrcnt++;
          }
  
          if ((brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC &&
              brt->brt_dst != bif) {
                  brt->brt_dst->bif_addrcnt--;
                  brt->brt_dst = bif;
                  brt->brt_dst->bif_addrcnt++;
          }
  
          if ((flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC)
                  brt->brt_expire = time_uptime + sc->sc_brttimeout;
          if (setflags)
                  brt->brt_flags = flags;
  
          return (0);
  }
  
  /*
   * bridge_rtlookup:
   *
   *      Lookup the destination interface for an address.
   */
  static struct ifnet *
  bridge_rtlookup(struct bridge_softc *sc, const uint8_t *addr, uint16_t vlan)
  {
          struct bridge_rtnode *brt;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          if ((brt = bridge_rtnode_lookup(sc, addr, vlan)) == NULL)
                  return (NULL);
  
          return (brt->brt_ifp);
  }
  
  /*
   * bridge_rttrim:
   *
   *      Trim the routine table so that we have a number
   *      of routing entries less than or equal to the
   *      maximum number.
   */
  static void
  bridge_rttrim(struct bridge_softc *sc)
  {
          struct bridge_rtnode *brt, *nbrt;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          /* Make sure we actually need to do this. */
          if (sc->sc_brtcnt <= sc->sc_brtmax)
                  return;
  
          /* Force an aging cycle; this might trim enough addresses. */
          bridge_rtage(sc);
          if (sc->sc_brtcnt <= sc->sc_brtmax)
                  return;
  
          LIST_FOREACH_SAFE(brt, &sc->sc_rtlist, brt_list, nbrt) {
                  if ((brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC) {
                          bridge_rtnode_destroy(sc, brt);
                          if (sc->sc_brtcnt <= sc->sc_brtmax)
                                  return;
                  }
          }
  }
  
  /*
   * bridge_timer:
   *
   *      Aging timer for the bridge.
   */
  static void
  bridge_timer(void *arg)
  {
          struct bridge_softc *sc = arg;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          bridge_rtage(sc);
  
          if (sc->sc_ifp->if_drv_flags & IFF_DRV_RUNNING)
                  callout_reset(&sc->sc_brcallout,
                      bridge_rtable_prune_period * hz, bridge_timer, sc);
  }
  
  /*
   * bridge_rtage:
   *
   *      Perform an aging cycle.
   */
  static void
  bridge_rtage(struct bridge_softc *sc)
  {
          struct bridge_rtnode *brt, *nbrt;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          LIST_FOREACH_SAFE(brt, &sc->sc_rtlist, brt_list, nbrt) {
                  if ((brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC) {
                          if (time_uptime >= brt->brt_expire)
                                  bridge_rtnode_destroy(sc, brt);
                  }
          }
  }
  
  /*
   * bridge_rtflush:
   *
   *      Remove all dynamic addresses from the bridge.
   */
  static void
  bridge_rtflush(struct bridge_softc *sc, int full)
  {
          struct bridge_rtnode *brt, *nbrt;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          LIST_FOREACH_SAFE(brt, &sc->sc_rtlist, brt_list, nbrt) {
                  if (full || (brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC)
                          bridge_rtnode_destroy(sc, brt);
          }
  }
  
  /*
   * bridge_rtdaddr:
   *
   *      Remove an address from the table.
   */
  static int
  bridge_rtdaddr(struct bridge_softc *sc, const uint8_t *addr, uint16_t vlan)
  {
          struct bridge_rtnode *brt;
          int found = 0;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          /*
           * If vlan is zero then we want to delete for all vlans so the lookup
           * may return more than one.
           */
          while ((brt = bridge_rtnode_lookup(sc, addr, vlan)) != NULL) {
                  bridge_rtnode_destroy(sc, brt);
                  found = 1;
          }
  
          return (found ? 0 : ENOENT);
  }
  
  /*
   * bridge_rtdelete:
   *
   *      Delete routes to a speicifc member interface.
   */
  static void
  bridge_rtdelete(struct bridge_softc *sc, struct ifnet *ifp, int full)
  {
          struct bridge_rtnode *brt, *nbrt;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          LIST_FOREACH_SAFE(brt, &sc->sc_rtlist, brt_list, nbrt) {
                  if (brt->brt_ifp == ifp && (full ||
                              (brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC))
                          bridge_rtnode_destroy(sc, brt);
          }
  }
  
  /*
   * bridge_rtable_init:
   *
   *      Initialize the route table for this bridge.
   */
  static void
  bridge_rtable_init(struct bridge_softc *sc)
  {
          int i;
  
          sc->sc_rthash = malloc(sizeof(*sc->sc_rthash) * BRIDGE_RTHASH_SIZE,
              M_DEVBUF, M_WAITOK);
  
          for (i = 0; i < BRIDGE_RTHASH_SIZE; i++)
                  LIST_INIT(&sc->sc_rthash[i]);
  
          sc->sc_rthash_key = arc4random();
          LIST_INIT(&sc->sc_rtlist);
  }
  
  /*
   * bridge_rtable_fini:
   *
   *      Deconstruct the route table for this bridge.
   */
  static void
  bridge_rtable_fini(struct bridge_softc *sc)
  {
  
          KASSERT(sc->sc_brtcnt == 0,
              ("%s: %d bridge routes referenced", __func__, sc->sc_brtcnt));
          free(sc->sc_rthash, M_DEVBUF);
  }
  
  /*
   * The following hash function is adapted from "Hash Functions" by Bob Jenkins
   * ("Algorithm Alley", Dr. Dobbs Journal, September 1997).
   */
  #define mix(a, b, c)                                                    \
  do {                                                                    \
          a -= b; a -= c; a ^= (c >> 13);                                 \
          b -= c; b -= a; b ^= (a << 8);                                  \
          c -= a; c -= b; c ^= (b >> 13);                                 \
          a -= b; a -= c; a ^= (c >> 12);                                 \
          b -= c; b -= a; b ^= (a << 16);                                 \
          c -= a; c -= b; c ^= (b >> 5);                                  \
          a -= b; a -= c; a ^= (c >> 3);                                  \
          b -= c; b -= a; b ^= (a << 10);                                 \
          c -= a; c -= b; c ^= (b >> 15);                                 \
  } while (/*CONSTCOND*/0)
  
  static __inline uint32_t
  bridge_rthash(struct bridge_softc *sc, const uint8_t *addr)
  {
          uint32_t a = 0x9e3779b9, b = 0x9e3779b9, c = sc->sc_rthash_key;
  
          b += addr[5] << 8;
          b += addr[4];
          a += addr[3] << 24;
          a += addr[2] << 16;
          a += addr[1] << 8;
          a += addr[0];
  
          mix(a, b, c);
  
          return (c & BRIDGE_RTHASH_MASK);
  }
  
  #undef mix
  
  static int
  bridge_rtnode_addr_cmp(const uint8_t *a, const uint8_t *b)
  {
          int i, d;
  
          for (i = 0, d = 0; i < ETHER_ADDR_LEN && d == 0; i++) {
                  d = ((int)a[i]) - ((int)b[i]);
          }
  
          return (d);
  }
  
  /*
   * bridge_rtnode_lookup:
   *
   *      Look up a bridge route node for the specified destination. Compare the
   *      vlan id or if zero then just return the first match.
   */
  static struct bridge_rtnode *
  bridge_rtnode_lookup(struct bridge_softc *sc, const uint8_t *addr, uint16_t vlan)
  {
          struct bridge_rtnode *brt;
          uint32_t hash;
          int dir;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          hash = bridge_rthash(sc, addr);
          LIST_FOREACH(brt, &sc->sc_rthash[hash], brt_hash) {
                  dir = bridge_rtnode_addr_cmp(addr, brt->brt_addr);
                  if (dir == 0 && (brt->brt_vlan == vlan || vlan == 0))
                          return (brt);
                  if (dir > 0)
                          return (NULL);
          }
  
          return (NULL);
  }
  
  /*
   * bridge_rtnode_insert:
   *
   *      Insert the specified bridge node into the route table.  We
   *      assume the entry is not already in the table.
   */
  static int
  bridge_rtnode_insert(struct bridge_softc *sc, struct bridge_rtnode *brt)
  {
          struct bridge_rtnode *lbrt;
          uint32_t hash;
          int dir;
  
          BRIDGE_LOCK_ASSERT(sc);
  
          hash = bridge_rthash(sc, brt->brt_addr);
  
          lbrt = LIST_FIRST(&sc->sc_rthash[hash]);
          if (lbrt == NULL) {
                  LIST_INSERT_HEAD(&sc->sc_rthash[hash], brt, brt_hash);
                  goto out;
          }
  
          do {
                  dir = bridge_rtnode_addr_cmp(brt->brt_addr, lbrt->brt_addr);
                  if (dir == 0 && brt->brt_vlan == lbrt->brt_vlan)
                          return (EEXIST);
                  if (dir > 0) {
                          LIST_INSERT_BEFORE(lbrt, brt, brt_hash);
                          goto out;
                  }
                  if (LIST_NEXT(lbrt, brt_hash) == NULL) {
                          LIST_INSERT_AFTER(lbrt, brt, brt_hash);
                          goto out;
                  }
                  lbrt = LIST_NEXT(lbrt, brt_hash);
          } while (lbrt != NULL);
  
  #ifdef DIAGNOSTIC
          panic("bridge_rtnode_insert: impossible");
  #endif
  
  out:
          LIST_INSERT_HEAD(&sc->sc_rtlist, brt, brt_list);
          sc->sc_brtcnt++;
  
          return (0);
  }
  
  /*
   * bridge_rtnode_destroy:
   *
   *      Destroy a bridge rtnode.
   */
  static void
  bridge_rtnode_destroy(struct bridge_softc *sc, struct bridge_rtnode *brt)
  {
          BRIDGE_LOCK_ASSERT(sc);
  
          LIST_REMOVE(brt, brt_hash);
  
          LIST_REMOVE(brt, brt_list);
          sc->sc_brtcnt--;
          brt->brt_dst->bif_addrcnt--;
          uma_zfree(bridge_rtnode_zone, brt);
  }
  
  /*
   * bridge_rtable_expire:
   *
   *      Set the expiry time for all routes on an interface.
   */
  static void
  bridge_rtable_expire(struct ifnet *ifp, int age)
  {
          struct bridge_softc *sc = ifp->if_bridge;
          struct bridge_rtnode *brt;
  
          BRIDGE_LOCK(sc);
  
          /*
           * If the age is zero then flush, otherwise set all the expiry times to
           * age for the interface
           */
          if (age == 0)
                  bridge_rtdelete(sc, ifp, IFBF_FLUSHDYN);
          else {
                  LIST_FOREACH(brt, &sc->sc_rtlist, brt_list) {
                          /* Cap the expiry time to 'age' */
                          if (brt->brt_ifp == ifp &&
                              brt->brt_expire > time_uptime + age &&
                              (brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC)
                                  brt->brt_expire = time_uptime + age;
                  }
          }
          BRIDGE_UNLOCK(sc);
  }
  
  /*
   * bridge_state_change:
   *
   *      Callback from the bridgestp code when a port changes states.
   */
  static void
  bridge_state_change(struct ifnet *ifp, int state)
  {
          struct bridge_softc *sc = ifp->if_bridge;
          static const char *stpstates[] = {
                  "disabled",
                  "listening",
                  "learning",
                  "forwarding",
                  "blocking",
                  "discarding"
          };
  
          if (log_stp)
                  log(LOG_NOTICE, "%s: state changed to %s on %s\n",
                      sc->sc_ifp->if_xname, stpstates[state], ifp->if_xname);
  }
  
  /*
   * Send bridge packets through pfil if they are one of the types pfil can deal
   * with, or if they are ARP or REVARP.  (pfil will pass ARP and REVARP without
   * question.) If *bifp or *ifp are NULL then packet filtering is skipped for
   * that interface.
   */
  static int
  bridge_pfil(struct mbuf **mp, struct ifnet *bifp, struct ifnet *ifp, int dir)
  {
          int snap, error, i, hlen;
          struct ether_header *eh1, eh2;
          struct ip *ip;
          struct llc llc1;
          u_int16_t ether_type;
  
          snap = 0;
          error = -1;     /* Default error if not error == 0 */
  
  #if 0
          /* we may return with the IP fields swapped, ensure its not shared */
          KASSERT(M_WRITABLE(*mp), ("%s: modifying a shared mbuf", __func__));
  #endif
  
          if (pfil_bridge == 0 && pfil_member == 0 && pfil_ipfw == 0)
                  return (0); /* filtering is disabled */
  
          i = min((*mp)->m_pkthdr.len, max_protohdr);
          if ((*mp)->m_len < i) {
              *mp = m_pullup(*mp, i);
              if (*mp == NULL) {
                  printf("%s: m_pullup failed\n", __func__);
                  return (-1);
              }
          }
  
          eh1 = mtod(*mp, struct ether_header *);
          ether_type = ntohs(eh1->ether_type);
  
          /*
           * Check for SNAP/LLC.
           */
          if (ether_type < ETHERMTU) {
                  struct llc *llc2 = (struct llc *)(eh1 + 1);
  
                  if ((*mp)->m_len >= ETHER_HDR_LEN + 8 &&
                      llc2->llc_dsap == LLC_SNAP_LSAP &&
                      llc2->llc_ssap == LLC_SNAP_LSAP &&
                      llc2->llc_control == LLC_UI) {
                          ether_type = htons(llc2->llc_un.type_snap.ether_type);
                          snap = 1;
                  }
          }
  
          /*
           * If we're trying to filter bridge traffic, don't look at anything
           * other than IP and ARP traffic.  If the filter doesn't understand
           * IPv6, don't allow IPv6 through the bridge either.  This is lame
           * since if we really wanted, say, an AppleTalk filter, we are hosed,
           * but of course we don't have an AppleTalk filter to begin with.
           * (Note that since pfil doesn't understand ARP it will pass *ALL*
           * ARP traffic.)
           */
          switch (ether_type) {
                  case ETHERTYPE_ARP:
                  case ETHERTYPE_REVARP:
                          if (pfil_ipfw_arp == 0)
                                  return (0); /* Automatically pass */
                          break;
  
                  case ETHERTYPE_IP:
  #ifdef INET6
                  case ETHERTYPE_IPV6:
  #endif /* INET6 */
                          break;
                  default:
                          /*
                           * Check to see if the user wants to pass non-ip
                           * packets, these will not be checked by pfil(9) and
                           * passed unconditionally so the default is to drop.
                           */
                          if (pfil_onlyip)
                                  goto bad;
          }
  
          /* Run the packet through pfil before stripping link headers */
          if (PFIL_HOOKED(&V_link_pfil_hook) && pfil_ipfw != 0 &&
                          dir == PFIL_OUT && ifp != NULL) {
  
                  error = pfil_run_hooks(&V_link_pfil_hook, mp, ifp, dir, NULL);
  
                  if (*mp == NULL || error != 0) /* packet consumed by filter */
                          return (error);
          }
  
          /* Strip off the Ethernet header and keep a copy. */
          m_copydata(*mp, 0, ETHER_HDR_LEN, (caddr_t) &eh2);
          m_adj(*mp, ETHER_HDR_LEN);
  
          /* Strip off snap header, if present */
          if (snap) {
                  m_copydata(*mp, 0, sizeof(struct llc), (caddr_t) &llc1);
                  m_adj(*mp, sizeof(struct llc));
          }
  
          /*
           * Check the IP header for alignment and errors
           */
          if (dir == PFIL_IN) {
                  switch (ether_type) {
                          case ETHERTYPE_IP:
                                  error = bridge_ip_checkbasic(mp);
                                  break;
  #ifdef INET6
                          case ETHERTYPE_IPV6:
                                  error = bridge_ip6_checkbasic(mp);
                                  break;
  #endif /* INET6 */
                          default:
                                  error = 0;
                  }
                  if (error)
                          goto bad;
          }
  
          error = 0;
  
          /*
           * Run the packet through pfil
           */
          switch (ether_type) {
          case ETHERTYPE_IP:
                  /*
                   * Run pfil on the member interface and the bridge, both can
                   * be skipped by clearing pfil_member or pfil_bridge.
                   *
                   * Keep the order:
                   *   in_if -> bridge_if -> out_if
                   */
                  if (pfil_bridge && dir == PFIL_OUT && bifp != NULL)
                          error = pfil_run_hooks(&V_inet_pfil_hook, mp, bifp,
                                          dir, NULL);
  
                  if (*mp == NULL || error != 0) /* filter may consume */
                          break;
  
                  if (pfil_member && ifp != NULL)
                          error = pfil_run_hooks(&V_inet_pfil_hook, mp, ifp,
                                          dir, NULL);
  
                  if (*mp == NULL || error != 0) /* filter may consume */
                          break;
  
                  if (pfil_bridge && dir == PFIL_IN && bifp != NULL)
                          error = pfil_run_hooks(&V_inet_pfil_hook, mp, bifp,
                                          dir, NULL);
  
                  if (*mp == NULL || error != 0) /* filter may consume */
                          break;
  
                  /* check if we need to fragment the packet */
                  /* bridge_fragment generates a mbuf chain of packets */
                  /* that already include eth headers */
                  if (pfil_member && ifp != NULL && dir == PFIL_OUT) {
                          i = (*mp)->m_pkthdr.len;
                          if (i > ifp->if_mtu) {
                                  error = bridge_fragment(ifp, mp, &eh2, snap,
                                              &llc1);
                                  return (error);
                          }
                  }
  
                  /* Recalculate the ip checksum. */
                  ip = mtod(*mp, struct ip *);
                  hlen = ip->ip_hl << 2;
                  if (hlen < sizeof(struct ip))
                          goto bad;
                  if (hlen > (*mp)->m_len) {
                          if ((*mp = m_pullup(*mp, hlen)) == 0)
                                  goto bad;
                          ip = mtod(*mp, struct ip *);
                          if (ip == NULL)
                                  goto bad;
                  }
                  ip->ip_sum = 0;
                  if (hlen == sizeof(struct ip))
                          ip->ip_sum = in_cksum_hdr(ip);
                  else
                          ip->ip_sum = in_cksum(*mp, hlen);
  
                  break;
  #ifdef INET6
          case ETHERTYPE_IPV6:
                  if (pfil_bridge && dir == PFIL_OUT && bifp != NULL)
                          error = pfil_run_hooks(&V_inet6_pfil_hook, mp, bifp,
                                          dir, NULL);
  
                  if (*mp == NULL || error != 0) /* filter may consume */
                          break;
  
                  if (pfil_member && ifp != NULL)
                          error = pfil_run_hooks(&V_inet6_pfil_hook, mp, ifp,
                                          dir, NULL);
  
                  if (*mp == NULL || error != 0) /* filter may consume */
                          break;
  
                  if (pfil_bridge && dir == PFIL_IN && bifp != NULL)
                          error = pfil_run_hooks(&V_inet6_pfil_hook, mp, bifp,
                                          dir, NULL);
                  break;
  #endif
          default:
                  error = 0;
                  break;
          }
  
          if (*mp == NULL)
                  return (error);
          if (error != 0)
                  goto bad;
  
          error = -1;
  
          /*
           * Finally, put everything back the way it was and return
           */
          if (snap) {
                  M_PREPEND(*mp, sizeof(struct llc), M_NOWAIT);
                  if (*mp == NULL)
                          return (error);
                  bcopy(&llc1, mtod(*mp, caddr_t), sizeof(struct llc));
          }
  
          M_PREPEND(*mp, ETHER_HDR_LEN, M_NOWAIT);
          if (*mp == NULL)
                  return (error);
          bcopy(&eh2, mtod(*mp, caddr_t), ETHER_HDR_LEN);
  
          return (0);
  
  bad:
          m_freem(*mp);
          *mp = NULL;
          return (error);
  }
  
  /*
   * Perform basic checks on header size since
   * pfil assumes ip_input has already processed
   * it for it.  Cut-and-pasted from ip_input.c.
   * Given how simple the IPv6 version is,
   * does the IPv4 version really need to be
   * this complicated?
   *
   * XXX Should we update ipstat here, or not?
   * XXX Right now we update ipstat but not
   * XXX csum_counter.
   */
  static int
  bridge_ip_checkbasic(struct mbuf **mp)
  {
          struct mbuf *m = *mp;
          struct ip *ip;
          int len, hlen;
          u_short sum;
  
          if (*mp == NULL)
                  return (-1);
  
          if (IP_HDR_ALIGNED_P(mtod(m, caddr_t)) == 0) {
                  if ((m = m_copyup(m, sizeof(struct ip),
                          (max_linkhdr + 3) & ~3)) == NULL) {
                          /* XXXJRT new stat, please */
                          KMOD_IPSTAT_INC(ips_toosmall);
                          goto bad;
                  }
          } else if (__predict_false(m->m_len < sizeof (struct ip))) {
                  if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
                          KMOD_IPSTAT_INC(ips_toosmall);
                          goto bad;
                  }
          }
          ip = mtod(m, struct ip *);
          if (ip == NULL) goto bad;
  
          if (ip->ip_v != IPVERSION) {
                  KMOD_IPSTAT_INC(ips_badvers);
                  goto bad;
          }
          hlen = ip->ip_hl << 2;
          if (hlen < sizeof(struct ip)) { /* minimum header length */
                  KMOD_IPSTAT_INC(ips_badhlen);
                  goto bad;
          }
          if (hlen > m->m_len) {
                  if ((m = m_pullup(m, hlen)) == 0) {
                          KMOD_IPSTAT_INC(ips_badhlen);
                          goto bad;
                  }
                  ip = mtod(m, struct ip *);
                  if (ip == NULL) goto bad;
          }
  
          if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
                  sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
          } else {
                  if (hlen == sizeof(struct ip)) {
                          sum = in_cksum_hdr(ip);
                  } else {
                          sum = in_cksum(m, hlen);
                  }
          }
          if (sum) {
                  KMOD_IPSTAT_INC(ips_badsum);
                  goto bad;
          }
  
          /* Retrieve the packet length. */
          len = ntohs(ip->ip_len);
  
          /*
           * Check for additional length bogosity
           */
          if (len < hlen) {
                  KMOD_IPSTAT_INC(ips_badlen);
                  goto bad;
          }
  
          /*
           * Check that the amount of data in the buffers
           * is as at least much as the IP header would have us expect.
           * Drop packet if shorter than we expect.
           */
          if (m->m_pkthdr.len < len) {
                  KMOD_IPSTAT_INC(ips_tooshort);
                  goto bad;
          }
  
          /* Checks out, proceed */
          *mp = m;
          return (0);
  
  bad:
          *mp = m;
          return (-1);
  }
  
  #ifdef INET6
  /*
   * Same as above, but for IPv6.
   * Cut-and-pasted from ip6_input.c.
   * XXX Should we update ip6stat, or not?
   */
  static int
  bridge_ip6_checkbasic(struct mbuf **mp)
  {
          struct mbuf *m = *mp;
          struct ip6_hdr *ip6;
  
          /*
           * If the IPv6 header is not aligned, slurp it up into a new
           * mbuf with space for link headers, in the event we forward
           * it.  Otherwise, if it is aligned, make sure the entire base
           * IPv6 header is in the first mbuf of the chain.
           */
          if (IP6_HDR_ALIGNED_P(mtod(m, caddr_t)) == 0) {
                  struct ifnet *inifp = m->m_pkthdr.rcvif;
                  if ((m = m_copyup(m, sizeof(struct ip6_hdr),
                              (max_linkhdr + 3) & ~3)) == NULL) {
                          /* XXXJRT new stat, please */
                          IP6STAT_INC(ip6s_toosmall);
                          in6_ifstat_inc(inifp, ifs6_in_hdrerr);
                          goto bad;
                  }
          } else if (__predict_false(m->m_len < sizeof(struct ip6_hdr))) {
                  struct ifnet *inifp = m->m_pkthdr.rcvif;
                  if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
                          IP6STAT_INC(ip6s_toosmall);
                          in6_ifstat_inc(inifp, ifs6_in_hdrerr);
                          goto bad;
                  }
          }
  
          ip6 = mtod(m, struct ip6_hdr *);
  
          if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
                  IP6STAT_INC(ip6s_badvers);
                  in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
                  goto bad;
          }
  
          /* Checks out, proceed */
          *mp = m;
          return (0);
  
  bad:
          *mp = m;
          return (-1);
  }
  #endif /* INET6 */
  
  /*
   * bridge_fragment:
   *
   *      Fragment mbuf chain in multiple packets and prepend ethernet header.
   */
  static int
  bridge_fragment(struct ifnet *ifp, struct mbuf **mp, struct ether_header *eh,
      int snap, struct llc *llc)
  {
          struct mbuf *m = *mp, *nextpkt = NULL, *mprev = NULL, *mcur = NULL;
          struct ip *ip;
          int error = -1;
  
          if (m->m_len < sizeof(struct ip) &&
              (m = m_pullup(m, sizeof(struct ip))) == NULL)
                  goto dropit;
          ip = mtod(m, struct ip *);
  
          m->m_pkthdr.csum_flags |= CSUM_IP;
          error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist);
          if (error)
                  goto dropit;
  
          /*
           * Walk the chain and re-add the Ethernet header for
           * each mbuf packet.
           */
          for (mcur = m; mcur; mcur = mcur->m_nextpkt) {
                  nextpkt = mcur->m_nextpkt;
                  mcur->m_nextpkt = NULL;
                  if (snap) {
                          M_PREPEND(mcur, sizeof(struct llc), M_NOWAIT);
                          if (mcur == NULL) {
                                  error = ENOBUFS;
                                  if (mprev != NULL)
                                          mprev->m_nextpkt = nextpkt;
                                  goto dropit;
                          }
                          bcopy(llc, mtod(mcur, caddr_t),sizeof(struct llc));
                  }
  
                  M_PREPEND(mcur, ETHER_HDR_LEN, M_NOWAIT);
                  if (mcur == NULL) {
                          error = ENOBUFS;
                          if (mprev != NULL)
                                  mprev->m_nextpkt = nextpkt;
                          goto dropit;
                  }
                  bcopy(eh, mtod(mcur, caddr_t), ETHER_HDR_LEN);
  
                  /*
                   * The previous two M_PREPEND could have inserted one or two
                   * mbufs in front so we have to update the previous packet's
                   * m_nextpkt.
                   */
                  mcur->m_nextpkt = nextpkt;
                  if (mprev != NULL)
                          mprev->m_nextpkt = mcur;
                  else {
                          /* The first mbuf in the original chain needs to be
                           * updated. */
                          *mp = mcur;
                  }
                  mprev = mcur;
          }
  
          KMOD_IPSTAT_INC(ips_fragmented);
          return (error);
  
  dropit:
          for (mcur = *mp; mcur; mcur = m) { /* droping the full packet chain */
                  m = mcur->m_nextpkt;
                  m_freem(mcur);
          }
          return (error);
  }
  
  static void
  bridge_linkstate(struct ifnet *ifp)
  {
          struct bridge_softc *sc = ifp->if_bridge;
          struct bridge_iflist *bif;
  
          BRIDGE_LOCK(sc);
          bif = bridge_lookup_member_if(sc, ifp);
          if (bif == NULL) {
                  BRIDGE_UNLOCK(sc);
                  return;
          }
          bridge_linkcheck(sc);
          BRIDGE_UNLOCK(sc);
  
          bstp_linkstate(&bif->bif_stp);
  }
  
  static void
  bridge_linkcheck(struct bridge_softc *sc)
  {
          struct bridge_iflist *bif;
          int new_link, hasls;
  
          BRIDGE_LOCK_ASSERT(sc);
          new_link = LINK_STATE_DOWN;
          hasls = 0;
          /* Our link is considered up if at least one of our ports is active */
          LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
                  if (bif->bif_ifp->if_capabilities & IFCAP_LINKSTATE)
                          hasls++;
                  if (bif->bif_ifp->if_link_state == LINK_STATE_UP) {
                          new_link = LINK_STATE_UP;
                          break;
                  }
          }
          if (!LIST_EMPTY(&sc->sc_iflist) && !hasls) {
                  /* If no interfaces support link-state then we default to up */
                  new_link = LINK_STATE_UP;
          }
          if_link_state_change(sc->sc_ifp, new_link);
  }