FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_mroute.c

     /*
      * IP multicast forwarding procedures
      *
      * Written by David Waitzman, BBN Labs, August 1988.
      * Modified by Steve Deering, Stanford, February 1989.
      * Modified by Mark J. Steiglitz, Stanford, May, 1991
      * Modified by Van Jacobson, LBL, January 1993
      * Modified by Ajit Thyagarajan, PARC, August 1993
      * Modified by Bill Fenner, PARC, April 1995
     * Modified by Ahmed Helmy, SGI, June 1996
     * Modified by George Edmond Eddy (Rusty), ISI, February 1998
     * Modified by Pavlin Radoslavov, USC/ISI, May 1998, August 1999, October 2000
     * Modified by Hitoshi Asaeda, WIDE, August 2000
     * Modified by Pavlin Radoslavov, ICSI, October 2002
     *
     * MROUTING Revision: 3.5
     * and PIM-SMv2 and PIM-DM support, advanced API support,
     * bandwidth metering and signaling
     *
     * $FreeBSD$
     */
    
    #include "opt_mrouting.h"
    #include "opt_random_ip_id.h"
    
    #ifdef PIM
    #define _PIM_VT 1
    #endif
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/protosw.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/sockio.h>
    #include <sys/sysctl.h>
    #include <sys/syslog.h>
    #include <sys/systm.h>
    #include <sys/time.h>
    #include <net/if.h>
    #include <net/route.h>
    #include <netinet/in.h>
    #include <netinet/igmp.h>
    #include <netinet/in_systm.h>
    #include <netinet/in_var.h>
    #include <netinet/ip.h>
    #include <netinet/ip_mroute.h>
    #include <netinet/ip_var.h>
    #ifdef PIM
    #include <netinet/pim.h>
    #include <netinet/pim_var.h>
    #endif
    #include <netinet/udp.h>
    #include <machine/in_cksum.h>
    
    /*
     * Control debugging code for rsvp and multicast routing code.
     * Can only set them with the debugger.
     */
    static  u_int   rsvpdebug;              /* non-zero enables debugging   */
    
    static  u_int   mrtdebug;               /* any set of the flags below   */
     
    #define         DEBUG_MFC       0x02
    #define         DEBUG_FORWARD   0x04
    #define         DEBUG_EXPIRE    0x08
    #define         DEBUG_XMIT      0x10
    #define         DEBUG_PIM       0x20
    
    #define         VIFI_INVALID    ((vifi_t) -1)
    
    #define M_HASCL(m)      ((m)->m_flags & M_EXT)
    
    static MALLOC_DEFINE(M_MRTABLE, "mroutetbl", "multicast routing tables");
    
    static struct mrtstat   mrtstat;
    SYSCTL_STRUCT(_net_inet_ip, OID_AUTO, mrtstat, CTLFLAG_RW,
        &mrtstat, mrtstat,
        "Multicast Routing Statistics (struct mrtstat, netinet/ip_mroute.h)");
    
    static struct mfc       *mfctable[MFCTBLSIZ];
    SYSCTL_OPAQUE(_net_inet_ip, OID_AUTO, mfctable, CTLFLAG_RD,
        &mfctable, sizeof(mfctable), "S,*mfc[MFCTBLSIZ]",
        "Multicast Forwarding Table (struct *mfc[MFCTBLSIZ], netinet/ip_mroute.h)");
    
    static struct vif       viftable[MAXVIFS];
    SYSCTL_OPAQUE(_net_inet_ip, OID_AUTO, viftable, CTLFLAG_RD,
        &viftable, sizeof(viftable), "S,vif[MAXVIFS]",
        "Multicast Virtual Interfaces (struct vif[MAXVIFS], netinet/ip_mroute.h)");
    
    static u_char           nexpire[MFCTBLSIZ];
    
    static struct callout_handle expire_upcalls_ch;
    
    #define         EXPIRE_TIMEOUT  (hz / 4)        /* 4x / second          */
    #define         UPCALL_EXPIRE   6               /* number of timeouts   */
    
   /*
    * Define the token bucket filter structures
    * tbftable -> each vif has one of these for storing info
    */
   
   static struct tbf tbftable[MAXVIFS];
   #define         TBF_REPROCESS   (hz / 100)      /* 100x / second */
   
   /*
    * 'Interfaces' associated with decapsulator (so we can tell
    * packets that went through it from ones that get reflected
    * by a broken gateway).  These interfaces are never linked into
    * the system ifnet list & no routes point to them.  I.e., packets
    * can't be sent this way.  They only exist as a placeholder for
    * multicast source verification.
    */
   static struct ifnet multicast_decap_if[MAXVIFS];
   
   #define ENCAP_TTL 64
   #define ENCAP_PROTO IPPROTO_IPIP        /* 4 */
   
   /* prototype IP hdr for encapsulated packets */
   static struct ip multicast_encap_iphdr = {
   #if BYTE_ORDER == LITTLE_ENDIAN
           sizeof(struct ip) >> 2, IPVERSION,
   #else
           IPVERSION, sizeof(struct ip) >> 2,
   #endif
           0,                              /* tos */
           sizeof(struct ip),              /* total length */
           0,                              /* id */
           0,                              /* frag offset */
           ENCAP_TTL, ENCAP_PROTO,
           0,                              /* checksum */
   };
   
   /*
    * Bandwidth meter variables and constants
    */
   static MALLOC_DEFINE(M_BWMETER, "bwmeter", "multicast upcall bw meters");
   /*
    * Pending timeouts are stored in a hash table, the key being the
    * expiration time. Periodically, the entries are analysed and processed.
    */
   #define BW_METER_BUCKETS        1024
   static struct bw_meter *bw_meter_timers[BW_METER_BUCKETS];
   static struct callout_handle bw_meter_ch;
   #define BW_METER_PERIOD (hz)            /* periodical handling of bw meters */
   
   /*
    * Pending upcalls are stored in a vector which is flushed when
    * full, or periodically
    */
   static struct bw_upcall bw_upcalls[BW_UPCALLS_MAX];
   static u_int    bw_upcalls_n; /* # of pending upcalls */
   static struct callout_handle bw_upcalls_ch;
   #define BW_UPCALLS_PERIOD (hz)          /* periodical flush of bw upcalls */
   
   #ifdef PIM
   static struct pimstat pimstat;
   SYSCTL_STRUCT(_net_inet_pim, PIMCTL_STATS, stats, CTLFLAG_RD,
       &pimstat, pimstat,
       "PIM Statistics (struct pimstat, netinet/pim_var.h)");
   
   /*
    * Note: the PIM Register encapsulation adds the following in front of a
    * data packet:
    *
    * struct pim_encap_hdr {
    *    struct ip ip;
    *    struct pim_encap_pimhdr  pim;
    * }
    *
    */
   
   struct pim_encap_pimhdr {
           struct pim pim;
           uint32_t   flags;
   };
   
   static struct ip pim_encap_iphdr = {
   #if BYTE_ORDER == LITTLE_ENDIAN
           sizeof(struct ip) >> 2,
           IPVERSION,
   #else
           IPVERSION,
           sizeof(struct ip) >> 2,
   #endif
           0,                      /* tos */
           sizeof(struct ip),      /* total length */
           0,                      /* id */
           0,                      /* frag offset */ 
           ENCAP_TTL,
           IPPROTO_PIM,
           0,                      /* checksum */
   };
   
   static struct pim_encap_pimhdr pim_encap_pimhdr = {
       {
           PIM_MAKE_VT(PIM_VERSION, PIM_REGISTER), /* PIM vers and message type */
           0,                      /* reserved */
           0,                      /* checksum */
       },
       0                           /* flags */
   };
   
   static struct ifnet multicast_register_if;
   static vifi_t reg_vif_num = VIFI_INVALID;
   #endif /* PIM */
   
   /*
    * Private variables.
    */
   static vifi_t      numvifs;
   static int have_encap_tunnel;
   
   /*
    * one-back cache used by ipip_input to locate a tunnel's vif
    * given a datagram's src ip address.
    */
   static u_long last_encap_src;
   static struct vif *last_encap_vif;
   
   static u_long   X_ip_mcast_src(int vifi);
   static int      X_ip_mforward(struct ip *ip, struct ifnet *ifp,
                           struct mbuf *m, struct ip_moptions *imo);
   static int      X_ip_mrouter_done(void);
   static int      X_ip_mrouter_get(struct socket *so, struct sockopt *m);
   static int      X_ip_mrouter_set(struct socket *so, struct sockopt *m);
   static int      X_legal_vif_num(int vif);
   static int      X_mrt_ioctl(int cmd, caddr_t data);
   
   static int get_sg_cnt(struct sioc_sg_req *);
   static int get_vif_cnt(struct sioc_vif_req *);
   static int ip_mrouter_init(struct socket *, int);
   static int add_vif(struct vifctl *);
   static int del_vif(vifi_t);
   static int add_mfc(struct mfcctl2 *);
   static int del_mfc(struct mfcctl2 *);
   static int set_api_config(uint32_t *); /* chose API capabilities */
   static int socket_send(struct socket *, struct mbuf *, struct sockaddr_in *);
   static int set_assert(int);
   static void expire_upcalls(void *);
   static int ip_mdq(struct mbuf *, struct ifnet *, struct mfc *, vifi_t);
   static void phyint_send(struct ip *, struct vif *, struct mbuf *);
   static void encap_send(struct ip *, struct vif *, struct mbuf *);
   static void tbf_control(struct vif *, struct mbuf *, struct ip *, u_long);
   static void tbf_queue(struct vif *, struct mbuf *);
   static void tbf_process_q(struct vif *);
   static void tbf_reprocess_q(void *);
   static int tbf_dq_sel(struct vif *, struct ip *);
   static void tbf_send_packet(struct vif *, struct mbuf *);
   static void tbf_update_tokens(struct vif *);
   static int priority(struct vif *, struct ip *);
   
   /*
    * Bandwidth monitoring
    */
   static void free_bw_list(struct bw_meter *list);
   static int add_bw_upcall(struct bw_upcall *);
   static int del_bw_upcall(struct bw_upcall *);
   static void bw_meter_receive_packet(struct bw_meter *x, int plen,
                   struct timeval *nowp);
   static void bw_meter_prepare_upcall(struct bw_meter *x, struct timeval *nowp);
   static void bw_upcalls_send(void);
   static void schedule_bw_meter(struct bw_meter *x, struct timeval *nowp);
   static void unschedule_bw_meter(struct bw_meter *x);
   static void bw_meter_process(void);
   static void expire_bw_upcalls_send(void *);
   static void expire_bw_meter_process(void *);
   
   #ifdef PIM
   static int pim_register_send(struct ip *, struct vif *,
                   struct mbuf *, struct mfc *);
   static int pim_register_send_rp(struct ip *, struct vif *,
                   struct mbuf *, struct mfc *);
   static int pim_register_send_upcall(struct ip *, struct vif *,
                   struct mbuf *, struct mfc *);
   static struct mbuf *pim_register_prepare(struct ip *, struct mbuf *);
   #endif
   
   /*
    * whether or not special PIM assert processing is enabled.
    */
   static int pim_assert;
   /*
    * Rate limit for assert notification messages, in usec
    */
   #define ASSERT_MSG_TIME         3000000
   
   /*
    * Kernel multicast routing API capabilities and setup.
    * If more API capabilities are added to the kernel, they should be
    * recorded in `mrt_api_support'.
    */
   static const uint32_t mrt_api_support = (MRT_MFC_FLAGS_DISABLE_WRONGVIF |
                                            MRT_MFC_FLAGS_BORDER_VIF |
                                            MRT_MFC_RP |
                                            MRT_MFC_BW_UPCALL);
   static uint32_t mrt_api_config = 0;
   
   /*
    * Hash function for a source, group entry
    */
   #define MFCHASH(a, g) MFCHASHMOD(((a) >> 20) ^ ((a) >> 10) ^ (a) ^ \
                           ((g) >> 20) ^ ((g) >> 10) ^ (g))
   
   /*
    * Find a route for a given origin IP address and Multicast group address
    * Type of service parameter to be added in the future!!!
    * Statistics are updated by the caller if needed
    * (mrtstat.mrts_mfc_lookups and mrtstat.mrts_mfc_misses)
    */
   static struct mfc *
   mfc_find(in_addr_t o, in_addr_t g)
   {
       struct mfc *rt;
   
       for (rt = mfctable[MFCHASH(o,g)]; rt; rt = rt->mfc_next)
           if ((rt->mfc_origin.s_addr == o) &&
                   (rt->mfc_mcastgrp.s_addr == g) && (rt->mfc_stall == NULL))
               break;
       return rt;
   }
   
   /*
    * Macros to compute elapsed time efficiently
    * Borrowed from Van Jacobson's scheduling code
    */
   #define TV_DELTA(a, b, delta) {                                 \
           int xxs;                                                \
           delta = (a).tv_usec - (b).tv_usec;                      \
           if ((xxs = (a).tv_sec - (b).tv_sec)) {                  \
                   switch (xxs) {                                  \
                   case 2:                                         \
                           delta += 1000000;                       \
                           /* FALLTHROUGH */                       \
                   case 1:                                         \
                           delta += 1000000;                       \
                           break;                                  \
                   default:                                        \
                           delta += (1000000 * xxs);               \
                   }                                               \
           }                                                       \
   }
   
   #define TV_LT(a, b) (((a).tv_usec < (b).tv_usec && \
                 (a).tv_sec <= (b).tv_sec) || (a).tv_sec < (b).tv_sec)
   
   /*
    * Handle MRT setsockopt commands to modify the multicast routing tables.
    */
   static int
   X_ip_mrouter_set(struct socket *so, struct sockopt *sopt)
   {
       int error, optval;
       vifi_t      vifi;
       struct      vifctl vifc;
       struct      mfcctl2 mfc;
       struct      bw_upcall bw_upcall;
       uint32_t    i;
   
       if (so != ip_mrouter && sopt->sopt_name != MRT_INIT)
           return EPERM;
   
       error = 0;
       switch (sopt->sopt_name) {
       case MRT_INIT:
           error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval);
           if (error)
               break;
           error = ip_mrouter_init(so, optval);
           break;
   
       case MRT_DONE:
           error = ip_mrouter_done();
           break;
   
       case MRT_ADD_VIF:
           error = sooptcopyin(sopt, &vifc, sizeof vifc, sizeof vifc);
           if (error)
               break;
           error = add_vif(&vifc);
           break;
   
       case MRT_DEL_VIF:
           error = sooptcopyin(sopt, &vifi, sizeof vifi, sizeof vifi);
           if (error)
               break;
           error = del_vif(vifi);
           break;
   
       case MRT_ADD_MFC:
       case MRT_DEL_MFC:
           /*
            * select data size depending on API version.
            */
           if (sopt->sopt_name == MRT_ADD_MFC &&
                   mrt_api_config & MRT_API_FLAGS_ALL) {
               error = sooptcopyin(sopt, &mfc, sizeof(struct mfcctl2),
                                   sizeof(struct mfcctl2));
           } else {
               error = sooptcopyin(sopt, &mfc, sizeof(struct mfcctl),
                                   sizeof(struct mfcctl));
               bzero((caddr_t)&mfc + sizeof(struct mfcctl),
                           sizeof(mfc) - sizeof(struct mfcctl));
           }
           if (error)
               break;
           if (sopt->sopt_name == MRT_ADD_MFC)
               error = add_mfc(&mfc);
           else
               error = del_mfc(&mfc);
           break;
   
       case MRT_ASSERT:
           error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval);
           if (error)
               break;
           set_assert(optval);
           break;
   
       case MRT_API_CONFIG:
           error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
           if (!error)
               error = set_api_config(&i);
           if (!error)
               error = sooptcopyout(sopt, &i, sizeof i);
           break;
   
       case MRT_ADD_BW_UPCALL:
       case MRT_DEL_BW_UPCALL:
           error = sooptcopyin(sopt, &bw_upcall, sizeof bw_upcall,
                                   sizeof bw_upcall);
           if (error)
               break;
           if (sopt->sopt_name == MRT_ADD_BW_UPCALL)
               error = add_bw_upcall(&bw_upcall);
           else
               error = del_bw_upcall(&bw_upcall);
           break;
   
       default:
           error = EOPNOTSUPP;
           break;
       }
       return error;
   }
   
   /*
    * Handle MRT getsockopt commands
    */
   static int
   X_ip_mrouter_get(struct socket *so, struct sockopt *sopt)
   {
       int error;
       static int version = 0x0305; /* !!! why is this here? XXX */
   
       switch (sopt->sopt_name) {
       case MRT_VERSION:
           error = sooptcopyout(sopt, &version, sizeof version);
           break;
   
       case MRT_ASSERT:
           error = sooptcopyout(sopt, &pim_assert, sizeof pim_assert);
           break;
   
       case MRT_API_SUPPORT:
           error = sooptcopyout(sopt, &mrt_api_support, sizeof mrt_api_support);
           break;
   
       case MRT_API_CONFIG:
           error = sooptcopyout(sopt, &mrt_api_config, sizeof mrt_api_config);
           break;
   
       default:
           error = EOPNOTSUPP;
           break;
       }
       return error;
   }
   
   /*
    * Handle ioctl commands to obtain information from the cache
    */
   static int
   X_mrt_ioctl(int cmd, caddr_t data)
   {
       int error = 0;
   
       switch (cmd) {
       case SIOCGETVIFCNT:
           error = get_vif_cnt((struct sioc_vif_req *)data);
           break;
   
       case SIOCGETSGCNT:
           error = get_sg_cnt((struct sioc_sg_req *)data);
           break;
   
       default:
           error = EINVAL;
           break;
       }
       return error;
   }
   
   /*
    * returns the packet, byte, rpf-failure count for the source group provided
    */
   static int
   get_sg_cnt(struct sioc_sg_req *req)
   {
       int s;
       struct mfc *rt;
   
       s = splnet();
       rt = mfc_find(req->src.s_addr, req->grp.s_addr);
       splx(s);
       if (rt == NULL) {
           req->pktcnt = req->bytecnt = req->wrong_if = 0xffffffff;
           return EADDRNOTAVAIL;
       }
       req->pktcnt = rt->mfc_pkt_cnt;
       req->bytecnt = rt->mfc_byte_cnt;
       req->wrong_if = rt->mfc_wrong_if;
       return 0;
   }
   
   /*
    * returns the input and output packet and byte counts on the vif provided
    */
   static int
   get_vif_cnt(struct sioc_vif_req *req)
   {
       vifi_t vifi = req->vifi;
   
       if (vifi >= numvifs)
           return EINVAL;
   
       req->icount = viftable[vifi].v_pkt_in;
       req->ocount = viftable[vifi].v_pkt_out;
       req->ibytes = viftable[vifi].v_bytes_in;
       req->obytes = viftable[vifi].v_bytes_out;
   
       return 0;
   }
   
   /*
    * Enable multicast routing
    */
   static int
   ip_mrouter_init(struct socket *so, int version)
   {
       if (mrtdebug)
           log(LOG_DEBUG, "ip_mrouter_init: so_type = %d, pr_protocol = %d\n",
               so->so_type, so->so_proto->pr_protocol);
   
       if (so->so_type != SOCK_RAW || so->so_proto->pr_protocol != IPPROTO_IGMP)
           return EOPNOTSUPP;
   
       if (version != 1)
           return ENOPROTOOPT;
   
       if (ip_mrouter != NULL)
           return EADDRINUSE;
   
       ip_mrouter = so;
   
       bzero((caddr_t)mfctable, sizeof(mfctable));
       bzero((caddr_t)nexpire, sizeof(nexpire));
   
       pim_assert = 0;
   
       expire_upcalls_ch = timeout(expire_upcalls, NULL, EXPIRE_TIMEOUT);
   
       bw_upcalls_n = 0;
       bzero((caddr_t)bw_meter_timers, sizeof(bw_meter_timers));
       bw_upcalls_ch = timeout(expire_bw_upcalls_send, NULL, BW_UPCALLS_PERIOD);
       bw_meter_ch = timeout(expire_bw_meter_process, NULL, BW_METER_PERIOD);
   
       mrt_api_config = 0;
   
       if (mrtdebug)
           log(LOG_DEBUG, "ip_mrouter_init\n");
   
       return 0;
   }
   
   /*
    * Disable multicast routing
    */
   static int
   X_ip_mrouter_done(void)
   {
       vifi_t vifi;
       int i;
       struct ifnet *ifp;
       struct ifreq ifr;
       struct mfc *rt;
       struct rtdetq *rte;
       int s;
   
       s = splnet();
   
       /*
        * For each phyint in use, disable promiscuous reception of all IP
        * multicasts.
        */
       for (vifi = 0; vifi < numvifs; vifi++) {
           if (viftable[vifi].v_lcl_addr.s_addr != 0 &&
                   !(viftable[vifi].v_flags & (VIFF_TUNNEL | VIFF_REGISTER))) {
               struct sockaddr_in *so = (struct sockaddr_in *)&(ifr.ifr_addr);
   
               so->sin_len = sizeof(struct sockaddr_in);
               so->sin_family = AF_INET;
               so->sin_addr.s_addr = INADDR_ANY;
               ifp = viftable[vifi].v_ifp;
               if_allmulti(ifp, 0);
           }
       }
       bzero((caddr_t)tbftable, sizeof(tbftable));
       bzero((caddr_t)viftable, sizeof(viftable));
       numvifs = 0;
       pim_assert = 0;
   
       untimeout(expire_upcalls, NULL, expire_upcalls_ch);
   
       mrt_api_config = 0;
       bw_upcalls_n = 0;
       untimeout(expire_bw_upcalls_send, NULL, bw_upcalls_ch);
       untimeout(expire_bw_meter_process, NULL, bw_meter_ch);
   
       /*
        * Free all multicast forwarding cache entries.
        */
       for (i = 0; i < MFCTBLSIZ; i++) {
           for (rt = mfctable[i]; rt != NULL; ) {
               struct mfc *nr = rt->mfc_next;
   
               for (rte = rt->mfc_stall; rte != NULL; ) {
                   struct rtdetq *n = rte->next;
   
                   m_freem(rte->m);
                   free(rte, M_MRTABLE);
                   rte = n;
               }
               free_bw_list(rt->mfc_bw_meter);
               free(rt, M_MRTABLE);
               rt = nr;
           }
       }
   
       bzero((caddr_t)mfctable, sizeof(mfctable));
   
       bzero(bw_meter_timers, sizeof(bw_meter_timers));
   
       /*
        * Reset de-encapsulation cache
        */
       last_encap_src = INADDR_ANY;
       last_encap_vif = NULL;
   #ifdef PIM
       reg_vif_num = VIFI_INVALID;
   #endif
       have_encap_tunnel = 0;
   
       ip_mrouter = NULL;
   
       splx(s);
   
       if (mrtdebug)
           log(LOG_DEBUG, "ip_mrouter_done\n");
   
       return 0;
   }
   
   /*
    * Set PIM assert processing global
    */
   static int
   set_assert(int i)
   {
       if ((i != 1) && (i != 0))
           return EINVAL;
   
       pim_assert = i;
   
       return 0;
   }
   
   /*
    * Configure API capabilities
    */
   int
   set_api_config(uint32_t *apival)
   {
       int i;
   
       /*
        * We can set the API capabilities only if it is the first operation
        * after MRT_INIT. I.e.:
        *  - there are no vifs installed
        *  - pim_assert is not enabled
        *  - the MFC table is empty
        */
       if (numvifs > 0) {
           *apival = 0;
           return EPERM;
       }
       if (pim_assert) {
           *apival = 0;
           return EPERM;
       }
       for (i = 0; i < MFCTBLSIZ; i++) {
           if (mfctable[i] != NULL) {
               *apival = 0;
               return EPERM;
           }
       }
   
       mrt_api_config = *apival & mrt_api_support;
       *apival = mrt_api_config;
   
       return 0;
   }
   
   /*
    * Add a vif to the vif table
    */
   static int
   add_vif(struct vifctl *vifcp)
   {
       struct vif *vifp = viftable + vifcp->vifc_vifi;
       struct sockaddr_in sin = {sizeof sin, AF_INET};
       struct ifaddr *ifa;
       struct ifnet *ifp;
       int error, s;
       struct tbf *v_tbf = tbftable + vifcp->vifc_vifi;
   
       if (vifcp->vifc_vifi >= MAXVIFS)
           return EINVAL;
       if (vifp->v_lcl_addr.s_addr != INADDR_ANY)
           return EADDRINUSE;
       if (vifcp->vifc_lcl_addr.s_addr == INADDR_ANY)
           return EADDRNOTAVAIL;
   
       /* Find the interface with an address in AF_INET family */
   #ifdef PIM
       if (vifcp->vifc_flags & VIFF_REGISTER) {
           /*
            * XXX: Because VIFF_REGISTER does not really need a valid
            * local interface (e.g. it could be 127.0.0.2), we don't
            * check its address.
            */
           ifp = NULL;
       } else
   #endif
       {
           sin.sin_addr = vifcp->vifc_lcl_addr;
           ifa = ifa_ifwithaddr((struct sockaddr *)&sin);
           if (ifa == NULL)
               return EADDRNOTAVAIL;
           ifp = ifa->ifa_ifp;
       }
   
       if (vifcp->vifc_flags & VIFF_TUNNEL) {
           if ((vifcp->vifc_flags & VIFF_SRCRT) == 0) {
               /*
                * An encapsulating tunnel is wanted.  Tell ipip_input() to
                * start paying attention to encapsulated packets.
                */
               if (have_encap_tunnel == 0) {
                   have_encap_tunnel = 1;
                   for (s = 0; s < MAXVIFS; ++s) {
                       multicast_decap_if[s].if_name = "mdecap";
                       multicast_decap_if[s].if_unit = s;
                   }
               }
               /*
                * Set interface to fake encapsulator interface
                */
               ifp = &multicast_decap_if[vifcp->vifc_vifi];
               /*
                * Prepare cached route entry
                */
               bzero(&vifp->v_route, sizeof(vifp->v_route));
           } else {
               log(LOG_ERR, "source routed tunnels not supported\n");
               return EOPNOTSUPP;
           }
   #ifdef PIM
       } else if (vifcp->vifc_flags & VIFF_REGISTER) {
           ifp = &multicast_register_if;
           if (mrtdebug)
               log(LOG_DEBUG, "Adding a register vif, ifp: %p\n",
                       (void *)&multicast_register_if);
           if (reg_vif_num == VIFI_INVALID) {
               multicast_register_if.if_name = "register_vif";
               multicast_register_if.if_unit = 0;
               multicast_register_if.if_flags = IFF_LOOPBACK;
               bzero(&vifp->v_route, sizeof(vifp->v_route));
               reg_vif_num = vifcp->vifc_vifi;
           }
   #endif
       } else {            /* Make sure the interface supports multicast */
           if ((ifp->if_flags & IFF_MULTICAST) == 0)
               return EOPNOTSUPP;
   
           /* Enable promiscuous reception of all IP multicasts from the if */
           s = splnet();
           error = if_allmulti(ifp, 1);
           splx(s);
           if (error)
               return error;
       }
   
       s = splnet();
       /* define parameters for the tbf structure */
       vifp->v_tbf = v_tbf;
       GET_TIME(vifp->v_tbf->tbf_last_pkt_t);
       vifp->v_tbf->tbf_n_tok = 0;
       vifp->v_tbf->tbf_q_len = 0;
       vifp->v_tbf->tbf_max_q_len = MAXQSIZE;
       vifp->v_tbf->tbf_q = vifp->v_tbf->tbf_t = NULL;
   
       vifp->v_flags     = vifcp->vifc_flags;
       vifp->v_threshold = vifcp->vifc_threshold;
       vifp->v_lcl_addr  = vifcp->vifc_lcl_addr;
       vifp->v_rmt_addr  = vifcp->vifc_rmt_addr;
       vifp->v_ifp       = ifp;
       /* scaling up here allows division by 1024 in critical code */
       vifp->v_rate_limit= vifcp->vifc_rate_limit * 1024 / 1000;
       vifp->v_rsvp_on   = 0;
       vifp->v_rsvpd     = NULL;
       /* initialize per vif pkt counters */
       vifp->v_pkt_in    = 0;
       vifp->v_pkt_out   = 0;
       vifp->v_bytes_in  = 0;
       vifp->v_bytes_out = 0;
       splx(s);
   
       /* Adjust numvifs up if the vifi is higher than numvifs */
       if (numvifs <= vifcp->vifc_vifi) numvifs = vifcp->vifc_vifi + 1;
   
       if (mrtdebug)
           log(LOG_DEBUG, "add_vif #%d, lcladdr %lx, %s %lx, thresh %x, rate %d\n",
               vifcp->vifc_vifi,
               (u_long)ntohl(vifcp->vifc_lcl_addr.s_addr),
               (vifcp->vifc_flags & VIFF_TUNNEL) ? "rmtaddr" : "mask",
               (u_long)ntohl(vifcp->vifc_rmt_addr.s_addr),
               vifcp->vifc_threshold,
               vifcp->vifc_rate_limit);
   
       return 0;
   }
   
   /*
    * Delete a vif from the vif table
    */
   static int
   del_vif(vifi_t vifi)
   {
       struct vif *vifp;
       int s;
   
       if (vifi >= numvifs)
           return EINVAL;
       vifp = &viftable[vifi];
       if (vifp->v_lcl_addr.s_addr == INADDR_ANY)
           return EADDRNOTAVAIL;
   
       s = splnet();
   
       if (!(vifp->v_flags & (VIFF_TUNNEL | VIFF_REGISTER)))
           if_allmulti(vifp->v_ifp, 0);
   
       if (vifp == last_encap_vif) {
           last_encap_vif = NULL;
           last_encap_src = INADDR_ANY;
       }
   
       /*
        * Free packets queued at the interface
        */
       while (vifp->v_tbf->tbf_q) {
           struct mbuf *m = vifp->v_tbf->tbf_q;
   
           vifp->v_tbf->tbf_q = m->m_act;
           m_freem(m);
       }
   
   #ifdef PIM
       if (vifp->v_flags & VIFF_REGISTER)
           reg_vif_num = VIFI_INVALID;
   #endif
   
       bzero((caddr_t)vifp->v_tbf, sizeof(*(vifp->v_tbf)));
       bzero((caddr_t)vifp, sizeof (*vifp));
   
       if (mrtdebug)
           log(LOG_DEBUG, "del_vif %d, numvifs %d\n", vifi, numvifs);
   
       /* Adjust numvifs down */
       for (vifi = numvifs; vifi > 0; vifi--)
           if (viftable[vifi-1].v_lcl_addr.s_addr != INADDR_ANY)
               break;
       numvifs = vifi;
   
       splx(s);
   
       return 0;
   }
   
   /*
    * update an mfc entry without resetting counters and S,G addresses.
    */
   static void
   update_mfc_params(struct mfc *rt, struct mfcctl2 *mfccp)
   {
       int i;
   
       rt->mfc_parent = mfccp->mfcc_parent;
       for (i = 0; i < numvifs; i++) {
           rt->mfc_ttls[i] = mfccp->mfcc_ttls[i];
           rt->mfc_flags[i] = mfccp->mfcc_flags[i] & mrt_api_config &
               MRT_MFC_FLAGS_ALL;
       }
       /* set the RP address */
       if (mrt_api_config & MRT_MFC_RP)
           rt->mfc_rp = mfccp->mfcc_rp;
       else
           rt->mfc_rp.s_addr = INADDR_ANY;
   }
   
   /*
    * fully initialize an mfc entry from the parameter.
    */
   static void
   init_mfc_params(struct mfc *rt, struct mfcctl2 *mfccp)
   {
       rt->mfc_origin     = mfccp->mfcc_origin;
       rt->mfc_mcastgrp   = mfccp->mfcc_mcastgrp;
   
       update_mfc_params(rt, mfccp);
   
       /* initialize pkt counters per src-grp */
       rt->mfc_pkt_cnt    = 0;
       rt->mfc_byte_cnt   = 0;
       rt->mfc_wrong_if   = 0;
       rt->mfc_last_assert.tv_sec = rt->mfc_last_assert.tv_usec = 0;
   }
   
   
   /*
    * Add an mfc entry
    */
   static int
   add_mfc(struct mfcctl2 *mfccp)
   {
       struct mfc *rt;
       u_long hash;
       struct rtdetq *rte;
       u_short nstl;
       int s;
   
       rt = mfc_find(mfccp->mfcc_origin.s_addr, mfccp->mfcc_mcastgrp.s_addr);
   
       /* If an entry already exists, just update the fields */
       if (rt) {
           if (mrtdebug & DEBUG_MFC)
               log(LOG_DEBUG,"add_mfc update o %lx g %lx p %x\n",
                   (u_long)ntohl(mfccp->mfcc_origin.s_addr),
                   (u_long)ntohl(mfccp->mfcc_mcastgrp.s_addr),
                   mfccp->mfcc_parent);
   
           s = splnet();
           update_mfc_params(rt, mfccp);
           splx(s);
           return 0;
       }
   
       /*
        * Find the entry for which the upcall was made and update
        */
       s = splnet();
       hash = MFCHASH(mfccp->mfcc_origin.s_addr, mfccp->mfcc_mcastgrp.s_addr);
       for (rt = mfctable[hash], nstl = 0; rt; rt = rt->mfc_next) {
   
           if ((rt->mfc_origin.s_addr == mfccp->mfcc_origin.s_addr) &&
                   (rt->mfc_mcastgrp.s_addr == mfccp->mfcc_mcastgrp.s_addr) &&
                   (rt->mfc_stall != NULL)) {
   
               if (nstl++)
                   log(LOG_ERR, "add_mfc %s o %lx g %lx p %x dbx %p\n",
                       "multiple kernel entries",
                       (u_long)ntohl(mfccp->mfcc_origin.s_addr),
                       (u_long)ntohl(mfccp->mfcc_mcastgrp.s_addr),
                       mfccp->mfcc_parent, (void *)rt->mfc_stall);
   
               if (mrtdebug & DEBUG_MFC)
                  log(LOG_DEBUG,"add_mfc o %lx g %lx p %x dbg %p\n",
                      (u_long)ntohl(mfccp->mfcc_origin.s_addr),
                      (u_long)ntohl(mfccp->mfcc_mcastgrp.s_addr),
                      mfccp->mfcc_parent, (void *)rt->mfc_stall);
  
              init_mfc_params(rt, mfccp);
  
              rt->mfc_expire = 0; /* Don't clean this guy up */
              nexpire[hash]--;
  
              /* free packets Qed at the end of this entry */
              for (rte = rt->mfc_stall; rte != NULL; ) {
                  struct rtdetq *n = rte->next;
  
                  ip_mdq(rte->m, rte->ifp, rt, -1);
                  m_freem(rte->m);
                  free(rte, M_MRTABLE);
                  rte = n;
              }
              rt->mfc_stall = NULL;
          }
      }
  
      /*
       * It is possible that an entry is being inserted without an upcall
       */
      if (nstl == 0) {
          if (mrtdebug & DEBUG_MFC)
              log(LOG_DEBUG,"add_mfc no upcall h %lu o %lx g %lx p %x\n",
                  hash, (u_long)ntohl(mfccp->mfcc_origin.s_addr),
                  (u_long)ntohl(mfccp->mfcc_mcastgrp.s_addr),
                  mfccp->mfcc_parent);
  
          for (rt = mfctable[hash]; rt != NULL; rt = rt->mfc_next) {
              if ((rt->mfc_origin.s_addr == mfccp->mfcc_origin.s_addr) &&
                      (rt->mfc_mcastgrp.s_addr == mfccp->mfcc_mcastgrp.s_addr)) {
                  init_mfc_params(rt, mfccp);
                  if (rt->mfc_expire)
                      nexpire[hash]--;
                  rt->mfc_expire = 0;
                  break; /* XXX */
              }
          }
          if (rt == NULL) {               /* no upcall, so make a new entry */
              rt = (struct mfc *)malloc(sizeof(*rt), M_MRTABLE, M_NOWAIT);
              if (rt == NULL) {
                  splx(s);
                  return ENOBUFS;
              }
  
              init_mfc_params(rt, mfccp);
              rt->mfc_expire     = 0;
              rt->mfc_stall      = NULL;
  
              rt->mfc_bw_meter = NULL;
              /* insert new entry at head of hash chain */
              rt->mfc_next = mfctable[hash];
              mfctable[hash] = rt;
          }
      }
      splx(s);
      return 0;
  }
  
  /*
   * Delete an mfc entry
   */
  static int
  del_mfc(struct mfcctl2 *mfccp)
  {
      struct in_addr      origin;
      struct in_addr      mcastgrp;
      struct mfc          *rt;
      struct mfc          **nptr;
      u_long              hash;
      int s;
      struct bw_meter     *list;
  
      origin = mfccp->mfcc_origin;
      mcastgrp = mfccp->mfcc_mcastgrp;
  
      if (mrtdebug & DEBUG_MFC)
          log(LOG_DEBUG,"del_mfc orig %lx mcastgrp %lx\n",
              (u_long)ntohl(origin.s_addr), (u_long)ntohl(mcastgrp.s_addr));
  
      s = splnet();
  
      hash = MFCHASH(origin.s_addr, mcastgrp.s_addr);
      for (nptr = &mfctable[hash]; (rt = *nptr) != NULL; nptr = &rt->mfc_next)
          if (origin.s_addr == rt->mfc_origin.s_addr &&
                  mcastgrp.s_addr == rt->mfc_mcastgrp.s_addr &&
                  rt->mfc_stall == NULL)
              break;
      if (rt == NULL) {
          splx(s);
          return EADDRNOTAVAIL;
      }
  
      *nptr = rt->mfc_next;
  
      /*
       * free the bw_meter entries
       */
      list = rt->mfc_bw_meter;
      rt->mfc_bw_meter = NULL;
  
      free(rt, M_MRTABLE);
  
      splx(s);
  
      free_bw_list(list);
  
      return 0;
  }
  
  /*
   * Send a message to mrouted on the multicast routing socket
   */
  static int
  socket_send(struct socket *s, struct mbuf *mm, struct sockaddr_in *src)
  {
      if (s) {
          if (sbappendaddr(&s->so_rcv, (struct sockaddr *)src, mm, NULL) != 0) {
              sorwakeup(s);
              return 0;
          }
      }
      m_freem(mm);
      return -1;
  }
  
  /*
   * IP multicast forwarding function. This function assumes that the packet
   * pointed to by "ip" has arrived on (or is about to be sent to) the interface
   * pointed to by "ifp", and the packet is to be relayed to other networks
   * that have members of the packet's destination IP multicast group.
   *
   * The packet is returned unscathed to the caller, unless it is
   * erroneous, in which case a non-zero return value tells the caller to
   * discard it.
   */
  
  #define TUNNEL_LEN  12  /* # bytes of IP option for tunnel encapsulation  */
  
  static int
  X_ip_mforward(struct ip *ip, struct ifnet *ifp, struct mbuf *m,
      struct ip_moptions *imo)
  {
      struct mfc *rt;
      int s;
      vifi_t vifi;
  
      if (mrtdebug & DEBUG_FORWARD)
          log(LOG_DEBUG, "ip_mforward: src %lx, dst %lx, ifp %p\n",
              (u_long)ntohl(ip->ip_src.s_addr), (u_long)ntohl(ip->ip_dst.s_addr),
              (void *)ifp);
  
      if (ip->ip_hl < (sizeof(struct ip) + TUNNEL_LEN) >> 2 ||
                  ((u_char *)(ip + 1))[1] != IPOPT_LSRR ) {
          /*
           * Packet arrived via a physical interface or
           * an encapsulated tunnel or a register_vif.
           */
      } else {
          /*
           * Packet arrived through a source-route tunnel.
           * Source-route tunnels are no longer supported.
           */
          static int last_log;
          if (last_log != time_second) {
              last_log = time_second;
              log(LOG_ERR,
                  "ip_mforward: received source-routed packet from %lx\n",
                  (u_long)ntohl(ip->ip_src.s_addr));
          }
          return 1;
      }
  
      if (imo && ((vifi = imo->imo_multicast_vif) < numvifs)) {
          if (ip->ip_ttl < 255)
              ip->ip_ttl++;       /* compensate for -1 in *_send routines */
          if (rsvpdebug && ip->ip_p == IPPROTO_RSVP) {
              struct vif *vifp = viftable + vifi;
  
              printf("Sending IPPROTO_RSVP from %lx to %lx on vif %d (%s%s%d)\n",
                  (long)ntohl(ip->ip_src.s_addr), (long)ntohl(ip->ip_dst.s_addr),
                  vifi,
                  (vifp->v_flags & VIFF_TUNNEL) ? "tunnel on " : "",
                  vifp->v_ifp->if_name, vifp->v_ifp->if_unit);
          }
          return ip_mdq(m, ifp, NULL, vifi);
      }
      if (rsvpdebug && ip->ip_p == IPPROTO_RSVP) {
          printf("Warning: IPPROTO_RSVP from %lx to %lx without vif option\n",
              (long)ntohl(ip->ip_src.s_addr), (long)ntohl(ip->ip_dst.s_addr));
          if (!imo)
              printf("In fact, no options were specified at all\n");
      }
  
      /*
       * Don't forward a packet with time-to-live of zero or one,
       * or a packet destined to a local-only group.
       */
      if (ip->ip_ttl <= 1 || ntohl(ip->ip_dst.s_addr) <= INADDR_MAX_LOCAL_GROUP)
          return 0;
  
      /*
       * Determine forwarding vifs from the forwarding cache table
       */
      s = splnet();
      ++mrtstat.mrts_mfc_lookups;
      rt = mfc_find(ip->ip_src.s_addr, ip->ip_dst.s_addr);
  
      /* Entry exists, so forward if necessary */
      if (rt != NULL) {
          splx(s);
          return ip_mdq(m, ifp, rt, -1);
      } else {
          /*
           * If we don't have a route for packet's origin,
           * Make a copy of the packet & send message to routing daemon
           */
  
          struct mbuf *mb0;
          struct rtdetq *rte;
          u_long hash;
          int hlen = ip->ip_hl << 2;
  
          ++mrtstat.mrts_mfc_misses;
  
          mrtstat.mrts_no_route++;
          if (mrtdebug & (DEBUG_FORWARD | DEBUG_MFC))
              log(LOG_DEBUG, "ip_mforward: no rte s %lx g %lx\n",
                  (u_long)ntohl(ip->ip_src.s_addr),
                  (u_long)ntohl(ip->ip_dst.s_addr));
  
          /*
           * Allocate mbufs early so that we don't do extra work if we are
           * just going to fail anyway.  Make sure to pullup the header so
           * that other people can't step on it.
           */
          rte = (struct rtdetq *)malloc((sizeof *rte), M_MRTABLE, M_NOWAIT);
          if (rte == NULL) {
              splx(s);
              return ENOBUFS;
          }
          mb0 = m_copypacket(m, M_DONTWAIT);
          if (mb0 && (M_HASCL(mb0) || mb0->m_len < hlen))
              mb0 = m_pullup(mb0, hlen);
          if (mb0 == NULL) {
              free(rte, M_MRTABLE);
              splx(s);
              return ENOBUFS;
          }
  
          /* is there an upcall waiting for this flow ? */
          hash = MFCHASH(ip->ip_src.s_addr, ip->ip_dst.s_addr);
          for (rt = mfctable[hash]; rt; rt = rt->mfc_next) {
              if ((ip->ip_src.s_addr == rt->mfc_origin.s_addr) &&
                      (ip->ip_dst.s_addr == rt->mfc_mcastgrp.s_addr) &&
                      (rt->mfc_stall != NULL))
                  break;
          }
  
          if (rt == NULL) {
              int i;
              struct igmpmsg *im;
              struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };
              struct mbuf *mm;
  
              /*
               * Locate the vifi for the incoming interface for this packet.
               * If none found, drop packet.
               */
              for (vifi=0; vifi < numvifs && viftable[vifi].v_ifp != ifp; vifi++)
                  ;
              if (vifi >= numvifs)        /* vif not found, drop packet */
                  goto non_fatal;
  
              /* no upcall, so make a new entry */
              rt = (struct mfc *)malloc(sizeof(*rt), M_MRTABLE, M_NOWAIT);
              if (rt == NULL)
                  goto fail;
              /* Make a copy of the header to send to the user level process */
              mm = m_copy(mb0, 0, hlen);
              if (mm == NULL)
                  goto fail1;
  
              /*
               * Send message to routing daemon to install
               * a route into the kernel table
               */
  
              im = mtod(mm, struct igmpmsg *);
              im->im_msgtype = IGMPMSG_NOCACHE;
              im->im_mbz = 0;
              im->im_vif = vifi;
  
              mrtstat.mrts_upcalls++;
  
              k_igmpsrc.sin_addr = ip->ip_src;
              if (socket_send(ip_mrouter, mm, &k_igmpsrc) < 0) {
                  log(LOG_WARNING, "ip_mforward: ip_mrouter socket queue full\n");
                  ++mrtstat.mrts_upq_sockfull;
  fail1:
                  free(rt, M_MRTABLE);
  fail:
                  free(rte, M_MRTABLE);
                  m_freem(mb0);
                  splx(s);
                  return ENOBUFS;
              }
  
              /* insert new entry at head of hash chain */
              rt->mfc_origin.s_addr     = ip->ip_src.s_addr;
              rt->mfc_mcastgrp.s_addr   = ip->ip_dst.s_addr;
              rt->mfc_expire            = UPCALL_EXPIRE;
              nexpire[hash]++;
              for (i = 0; i < numvifs; i++) {
                  rt->mfc_ttls[i] = 0;
                  rt->mfc_flags[i] = 0;
              }
              rt->mfc_parent = -1;
  
              rt->mfc_rp.s_addr = INADDR_ANY; /* clear the RP address */
  
              rt->mfc_bw_meter = NULL;
  
              /* link into table */
              rt->mfc_next   = mfctable[hash];
              mfctable[hash] = rt;
              rt->mfc_stall = rte;
  
          } else {
              /* determine if q has overflowed */
              int npkts = 0;
              struct rtdetq **p;
  
              /*
               * XXX ouch! we need to append to the list, but we
               * only have a pointer to the front, so we have to
               * scan the entire list every time.
               */
              for (p = &rt->mfc_stall; *p != NULL; p = &(*p)->next)
                  npkts++;
  
              if (npkts > MAX_UPQ) {
                  mrtstat.mrts_upq_ovflw++;
  non_fatal:
                  free(rte, M_MRTABLE);
                  m_freem(mb0);
                  splx(s);
                  return 0;
              }
  
              /* Add this entry to the end of the queue */
              *p = rte;
          }
  
          rte->m                  = mb0;
          rte->ifp                = ifp;
          rte->next               = NULL;
  
          splx(s);
  
          return 0;
      }
  }
  
  /*
   * Clean up the cache entry if upcall is not serviced
   */
  static void
  expire_upcalls(void *unused)
  {
      struct rtdetq *rte;
      struct mfc *mfc, **nptr;
      int i;
      int s;
  
      s = splnet();
      for (i = 0; i < MFCTBLSIZ; i++) {
          if (nexpire[i] == 0)
              continue;
          nptr = &mfctable[i];
          for (mfc = *nptr; mfc != NULL; mfc = *nptr) {
              /*
               * Skip real cache entries
               * Make sure it wasn't marked to not expire (shouldn't happen)
               * If it expires now
               */
              if (mfc->mfc_stall != NULL && mfc->mfc_expire != 0 &&
                      --mfc->mfc_expire == 0) {
                  if (mrtdebug & DEBUG_EXPIRE)
                      log(LOG_DEBUG, "expire_upcalls: expiring (%lx %lx)\n",
                          (u_long)ntohl(mfc->mfc_origin.s_addr),
                          (u_long)ntohl(mfc->mfc_mcastgrp.s_addr));
                  /*
                   * drop all the packets
                   * free the mbuf with the pkt, if, timing info
                   */
                  for (rte = mfc->mfc_stall; rte; ) {
                      struct rtdetq *n = rte->next;
  
                      m_freem(rte->m);
                      free(rte, M_MRTABLE);
                      rte = n;
                  }
                  ++mrtstat.mrts_cache_cleanups;
                  nexpire[i]--;
  
                  /*
                   * free the bw_meter entries
                   */
                  while (mfc->mfc_bw_meter != NULL) {
                      struct bw_meter *x = mfc->mfc_bw_meter;
  
                      mfc->mfc_bw_meter = x->bm_mfc_next;
                      free(x, M_BWMETER);
                  }
  
                  *nptr = mfc->mfc_next;
                  free(mfc, M_MRTABLE);
              } else {
                  nptr = &mfc->mfc_next;
              }
          }
      }
      splx(s);
      expire_upcalls_ch = timeout(expire_upcalls, NULL, EXPIRE_TIMEOUT);
  }
  
  /*
   * Packet forwarding routine once entry in the cache is made
   */
  static int
  ip_mdq(struct mbuf *m, struct ifnet *ifp, struct mfc *rt, vifi_t xmt_vif)
  {
      struct ip  *ip = mtod(m, struct ip *);
      vifi_t vifi;
      int plen = ip->ip_len;
  
  /*
   * Macro to send packet on vif.  Since RSVP packets don't get counted on
   * input, they shouldn't get counted on output, so statistics keeping is
   * separate.
   */
  #define MC_SEND(ip,vifp,m) {                            \
                  if ((vifp)->v_flags & VIFF_TUNNEL)      \
                      encap_send((ip), (vifp), (m));      \
                  else                                    \
                      phyint_send((ip), (vifp), (m));     \
  }
  
      /*
       * If xmt_vif is not -1, send on only the requested vif.
       *
       * (since vifi_t is u_short, -1 becomes MAXUSHORT, which > numvifs.)
       */
      if (xmt_vif < numvifs) {
  #ifdef PIM
          if (viftable[xmt_vif].v_flags & VIFF_REGISTER)
              pim_register_send(ip, viftable + xmt_vif, m, rt);
          else
  #endif
          MC_SEND(ip, viftable + xmt_vif, m);
          return 1;
      }
  
      /*
       * Don't forward if it didn't arrive from the parent vif for its origin.
       */
      vifi = rt->mfc_parent;
      if ((vifi >= numvifs) || (viftable[vifi].v_ifp != ifp)) {
          /* came in the wrong interface */
          if (mrtdebug & DEBUG_FORWARD)
              log(LOG_DEBUG, "wrong if: ifp %p vifi %d vififp %p\n",
                  (void *)ifp, vifi, (void *)viftable[vifi].v_ifp);
          ++mrtstat.mrts_wrong_if;
          ++rt->mfc_wrong_if;
          /*
           * If we are doing PIM assert processing, send a message
           * to the routing daemon.
           *
           * XXX: A PIM-SM router needs the WRONGVIF detection so it
           * can complete the SPT switch, regardless of the type
           * of the iif (broadcast media, GRE tunnel, etc).
           */
          if (pim_assert && (vifi < numvifs) && viftable[vifi].v_ifp) {
              struct timeval now;
              u_long delta;
  
  #ifdef PIM
              if (ifp == &multicast_register_if)
                  pimstat.pims_rcv_registers_wrongiif++;
  #endif
  
              /* Get vifi for the incoming packet */
              for (vifi=0; vifi < numvifs && viftable[vifi].v_ifp != ifp; vifi++)
                  ;
              if (vifi >= numvifs)
                  return 0;       /* The iif is not found: ignore the packet. */
  
              if (rt->mfc_flags[vifi] & MRT_MFC_FLAGS_DISABLE_WRONGVIF)
                  return 0;       /* WRONGVIF disabled: ignore the packet */
  
              GET_TIME(now);
  
              TV_DELTA(rt->mfc_last_assert, now, delta);
  
              if (delta > ASSERT_MSG_TIME) {
                  struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };
                  struct igmpmsg *im;
                  int hlen = ip->ip_hl << 2;
                  struct mbuf *mm = m_copy(m, 0, hlen);
  
                  if (mm && (M_HASCL(mm) || mm->m_len < hlen))
                      mm = m_pullup(mm, hlen);
                  if (mm == NULL)
                      return ENOBUFS;
  
                  rt->mfc_last_assert = now;
  
                  im = mtod(mm, struct igmpmsg *);
                  im->im_msgtype  = IGMPMSG_WRONGVIF;
                  im->im_mbz              = 0;
                  im->im_vif              = vifi;
  
                  mrtstat.mrts_upcalls++;
  
                  k_igmpsrc.sin_addr = im->im_src;
                  if (socket_send(ip_mrouter, mm, &k_igmpsrc) < 0) {
                      log(LOG_WARNING,
                          "ip_mforward: ip_mrouter socket queue full\n");
                      ++mrtstat.mrts_upq_sockfull;
                      return ENOBUFS;
                  }
              }
          }
          return 0;
      }
  
      /* If I sourced this packet, it counts as output, else it was input. */
      if (ip->ip_src.s_addr == viftable[vifi].v_lcl_addr.s_addr) {
          viftable[vifi].v_pkt_out++;
          viftable[vifi].v_bytes_out += plen;
      } else {
          viftable[vifi].v_pkt_in++;
          viftable[vifi].v_bytes_in += plen;
      }
      rt->mfc_pkt_cnt++;
      rt->mfc_byte_cnt += plen;
  
      /*
       * For each vif, decide if a copy of the packet should be forwarded.
       * Forward if:
       *          - the ttl exceeds the vif's threshold
       *          - there are group members downstream on interface
       */
      for (vifi = 0; vifi < numvifs; vifi++)
          if ((rt->mfc_ttls[vifi] > 0) && (ip->ip_ttl > rt->mfc_ttls[vifi])) {
              viftable[vifi].v_pkt_out++;
              viftable[vifi].v_bytes_out += plen;
  #ifdef PIM
              if (viftable[vifi].v_flags & VIFF_REGISTER)
                  pim_register_send(ip, viftable + vifi, m, rt);
              else
  #endif
              MC_SEND(ip, viftable+vifi, m);
          }
  
      /*
       * Perform upcall-related bw measuring.
       */
      if (rt->mfc_bw_meter != NULL) {
          struct bw_meter *x;
          struct timeval now;
  
          GET_TIME(now);
          for (x = rt->mfc_bw_meter; x != NULL; x = x->bm_mfc_next)
              bw_meter_receive_packet(x, plen, &now);
      }
  
      return 0;
  }
  
  /*
   * check if a vif number is legal/ok. This is used by ip_output.
   */
  static int
  X_legal_vif_num(int vif)
  {
      return (vif >= 0 && vif < numvifs);
  }
  
  /*
   * Return the local address used by this vif
   */
  static u_long
  X_ip_mcast_src(int vifi)
  {
      if (vifi >= 0 && vifi < numvifs)
          return viftable[vifi].v_lcl_addr.s_addr;
      else
          return INADDR_ANY;
  }
  
  static void
  phyint_send(struct ip *ip, struct vif *vifp, struct mbuf *m)
  {
      struct mbuf *mb_copy;
      int hlen = ip->ip_hl << 2;
  
      /*
       * Make a new reference to the packet; make sure that
       * the IP header is actually copied, not just referenced,
       * so that ip_output() only scribbles on the copy.
       */
      mb_copy = m_copypacket(m, M_DONTWAIT);
      if (mb_copy && (M_HASCL(mb_copy) || mb_copy->m_len < hlen))
          mb_copy = m_pullup(mb_copy, hlen);
      if (mb_copy == NULL)
          return;
  
      if (vifp->v_rate_limit == 0)
          tbf_send_packet(vifp, mb_copy);
      else
          tbf_control(vifp, mb_copy, mtod(mb_copy, struct ip *), ip->ip_len);
  }
  
  static void
  encap_send(struct ip *ip, struct vif *vifp, struct mbuf *m)
  {
      struct mbuf *mb_copy;
      struct ip *ip_copy;
      int i, len = ip->ip_len;
  
      /* Take care of delayed checksums */
      if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
          in_delayed_cksum(m);
          m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
      }
  
      /*
       * copy the old packet & pullup its IP header into the
       * new mbuf so we can modify it.  Try to fill the new
       * mbuf since if we don't the ethernet driver will.
       */
      MGETHDR(mb_copy, M_DONTWAIT, MT_HEADER);
      if (mb_copy == NULL)
          return;
      mb_copy->m_data += max_linkhdr;
      mb_copy->m_len = sizeof(multicast_encap_iphdr);
  
      if ((mb_copy->m_next = m_copypacket(m, M_DONTWAIT)) == NULL) {
          m_freem(mb_copy);
          return;
      }
      i = MHLEN - M_LEADINGSPACE(mb_copy);
      if (i > len)
          i = len;
      mb_copy = m_pullup(mb_copy, i);
      if (mb_copy == NULL)
          return;
      mb_copy->m_pkthdr.len = len + sizeof(multicast_encap_iphdr);
  
      /*
       * fill in the encapsulating IP header.
       */
      ip_copy = mtod(mb_copy, struct ip *);
      *ip_copy = multicast_encap_iphdr;
  #ifdef RANDOM_IP_ID
      ip_copy->ip_id = ip_randomid();
  #else
      ip_copy->ip_id = htons(ip_id++);
  #endif
      ip_copy->ip_len += len;
      ip_copy->ip_src = vifp->v_lcl_addr;
      ip_copy->ip_dst = vifp->v_rmt_addr;
  
      /*
       * turn the encapsulated IP header back into a valid one.
       */
      ip = (struct ip *)((caddr_t)ip_copy + sizeof(multicast_encap_iphdr));
      --ip->ip_ttl;
      ip->ip_len = htons(ip->ip_len);
      ip->ip_off = htons(ip->ip_off);
      ip->ip_sum = 0;
      mb_copy->m_data += sizeof(multicast_encap_iphdr);
      ip->ip_sum = in_cksum(mb_copy, ip->ip_hl << 2);
      mb_copy->m_data -= sizeof(multicast_encap_iphdr);
  
      if (vifp->v_rate_limit == 0)
          tbf_send_packet(vifp, mb_copy);
      else
          tbf_control(vifp, mb_copy, ip, ip_copy->ip_len);
  }
  
  /*
   * De-encapsulate a packet and feed it back through ip input (this
   * routine is called whenever IP gets a packet with proto type
   * ENCAP_PROTO and a local destination address).
   *
   * This is similar to mroute_encapcheck() + mroute_encap_input() in -current.
   */
  static void
  X_ipip_input(struct mbuf *m, int off, int proto)
  {
      struct ip *ip = mtod(m, struct ip *);
      int hlen = ip->ip_hl << 2;
      int s;
      struct ifqueue *ifq;
  
      if (!have_encap_tunnel) {
          rip_input(m, off, proto);
          return;
      }
      /*
       * dump the packet if it's not to a multicast destination or if
       * we don't have an encapsulating tunnel with the source.
       * Note:  This code assumes that the remote site IP address
       * uniquely identifies the tunnel (i.e., that this site has
       * at most one tunnel with the remote site).
       */
      if (!IN_MULTICAST(ntohl(((struct ip *)((char *)ip+hlen))->ip_dst.s_addr))) {
          ++mrtstat.mrts_bad_tunnel;
          m_freem(m);
          return;
      }
      if (ip->ip_src.s_addr != last_encap_src) {
          struct vif *vifp = viftable;
          struct vif *vife = vifp + numvifs;
  
          last_encap_src = ip->ip_src.s_addr;
          last_encap_vif = NULL;
          for ( ; vifp < vife; ++vifp)
              if (vifp->v_rmt_addr.s_addr == ip->ip_src.s_addr) {
                  if ((vifp->v_flags & (VIFF_TUNNEL|VIFF_SRCRT))
                      == VIFF_TUNNEL)
                      last_encap_vif = vifp;
                  break;
              }
      }
      if (last_encap_vif == NULL) {
          last_encap_src = INADDR_ANY;
          mrtstat.mrts_cant_tunnel++; /*XXX*/
          m_freem(m);
          if (mrtdebug)
              log(LOG_DEBUG, "ip_mforward: no tunnel with %lx\n",
                  (u_long)ntohl(ip->ip_src.s_addr));
          return;
      }
  
      if (hlen > sizeof(struct ip))
          ip_stripoptions(m, NULL);
      m->m_data += sizeof(struct ip);
      m->m_len -= sizeof(struct ip);
      m->m_pkthdr.len -= sizeof(struct ip);
      m->m_pkthdr.rcvif = last_encap_vif->v_ifp;
  
      ifq = &ipintrq;
      s = splimp();
      if (IF_QFULL(ifq)) {
          IF_DROP(ifq);
          m_freem(m);
      } else {
          IF_ENQUEUE(ifq, m);
          /*
           * normally we would need a "schednetisr(NETISR_IP)"
           * here but we were called by ip_input and it is going
           * to loop back & try to dequeue the packet we just
           * queued as soon as we return so we avoid the
           * unnecessary software interrrupt.
           */
      }
      splx(s);
  }
  
  /*
   * Token bucket filter module
   */
  
  static void
  tbf_control(struct vif *vifp, struct mbuf *m, struct ip *ip, u_long p_len)
  {
      struct tbf *t = vifp->v_tbf;
  
      if (p_len > MAX_BKT_SIZE) {         /* drop if packet is too large */
          mrtstat.mrts_pkt2large++;
          m_freem(m);
          return;
      }
  
      tbf_update_tokens(vifp);
  
      if (t->tbf_q_len == 0) {            /* queue empty...               */
          if (p_len <= t->tbf_n_tok) {    /* send packet if enough tokens */
              t->tbf_n_tok -= p_len;
              tbf_send_packet(vifp, m);
          } else {                        /* no, queue packet and try later */
              tbf_queue(vifp, m);
              timeout(tbf_reprocess_q, (caddr_t)vifp, TBF_REPROCESS);
          }
      } else if (t->tbf_q_len < t->tbf_max_q_len) {
          /* finite queue length, so queue pkts and process queue */
          tbf_queue(vifp, m);
          tbf_process_q(vifp);
      } else {
          /* queue full, try to dq and queue and process */
          if (!tbf_dq_sel(vifp, ip)) {
              mrtstat.mrts_q_overflow++;
              m_freem(m);
          } else {
              tbf_queue(vifp, m);
              tbf_process_q(vifp);
          }
      }
  }
  
  /*
   * adds a packet to the queue at the interface
   */
  static void
  tbf_queue(struct vif *vifp, struct mbuf *m)
  {
      int s = splnet();
      struct tbf *t = vifp->v_tbf;
  
      if (t->tbf_t == NULL)       /* Queue was empty */
          t->tbf_q = m;
      else                        /* Insert at tail */
          t->tbf_t->m_act = m;
  
      t->tbf_t = m;               /* Set new tail pointer */
  
  #ifdef DIAGNOSTIC
      /* Make sure we didn't get fed a bogus mbuf */
      if (m->m_act)
          panic("tbf_queue: m_act");
  #endif
      m->m_act = NULL;
  
      t->tbf_q_len++;
  
      splx(s);
  }
  
  /*
   * processes the queue at the interface
   */
  static void
  tbf_process_q(struct vif *vifp)
  {
      int s = splnet();
      struct tbf *t = vifp->v_tbf;
  
      /* loop through the queue at the interface and send as many packets
       * as possible
       */
      while (t->tbf_q_len > 0) {
          struct mbuf *m = t->tbf_q;
          int len = mtod(m, struct ip *)->ip_len;
  
          /* determine if the packet can be sent */
          if (len > t->tbf_n_tok) /* not enough tokens, we are done */
              break;
          /* ok, reduce no of tokens, dequeue and send the packet. */
          t->tbf_n_tok -= len;
  
          t->tbf_q = m->m_act;
          if (--t->tbf_q_len == 0)
              t->tbf_t = NULL;
  
          m->m_act = NULL;
          tbf_send_packet(vifp, m);
      }
      splx(s);
  }
  
  static void
  tbf_reprocess_q(void *xvifp)
  {
      struct vif *vifp = xvifp;
  
      if (ip_mrouter == NULL)
          return;
      tbf_update_tokens(vifp);
      tbf_process_q(vifp);
      if (vifp->v_tbf->tbf_q_len)
          timeout(tbf_reprocess_q, (caddr_t)vifp, TBF_REPROCESS);
  }
  
  /* function that will selectively discard a member of the queue
   * based on the precedence value and the priority
   */
  static int
  tbf_dq_sel(struct vif *vifp, struct ip *ip)
  {
      int s = splnet();
      u_int p;
      struct mbuf *m, *last;
      struct mbuf **np;
      struct tbf *t = vifp->v_tbf;
  
      p = priority(vifp, ip);
  
      np = &t->tbf_q;
      last = NULL;
      while ((m = *np) != NULL) {
          if (p > priority(vifp, mtod(m, struct ip *))) {
              *np = m->m_act;
              /* If we're removing the last packet, fix the tail pointer */
              if (m == t->tbf_t)
                  t->tbf_t = last;
              m_freem(m);
              /* It's impossible for the queue to be empty, but check anyways. */
              if (--t->tbf_q_len == 0)
                  t->tbf_t = NULL;
              splx(s);
              mrtstat.mrts_drop_sel++;
              return 1;
          }
          np = &m->m_act;
          last = m;
      }
      splx(s);
      return 0;
  }
  
  static void
  tbf_send_packet(struct vif *vifp, struct mbuf *m)
  {
      int s = splnet();
  
      if (vifp->v_flags & VIFF_TUNNEL)    /* If tunnel options */
          ip_output(m, NULL, &vifp->v_route, IP_FORWARDING, NULL, NULL);
      else {
          struct ip_moptions imo;
          int error;
          static struct route ro; /* XXX check this */
  
          imo.imo_multicast_ifp  = vifp->v_ifp;
          imo.imo_multicast_ttl  = mtod(m, struct ip *)->ip_ttl - 1;
          imo.imo_multicast_loop = 1;
          imo.imo_multicast_vif  = -1;
  
          /*
           * Re-entrancy should not be a problem here, because
           * the packets that we send out and are looped back at us
           * should get rejected because they appear to come from
           * the loopback interface, thus preventing looping.
           */
          error = ip_output(m, NULL, &ro, IP_FORWARDING, &imo, NULL);
  
          if (mrtdebug & DEBUG_XMIT)
              log(LOG_DEBUG, "phyint_send on vif %d err %d\n",
                  (int)(vifp - viftable), error);
      }
      splx(s);
  }
  
  /* determine the current time and then
   * the elapsed time (between the last time and time now)
   * in milliseconds & update the no. of tokens in the bucket
   */
  static void
  tbf_update_tokens(struct vif *vifp)
  {
      struct timeval tp;
      u_long tm;
      int s = splnet();
      struct tbf *t = vifp->v_tbf;
  
      GET_TIME(tp);
  
      TV_DELTA(tp, t->tbf_last_pkt_t, tm);
  
      /*
       * This formula is actually
       * "time in seconds" * "bytes/second".
       *
       * (tm / 1000000) * (v_rate_limit * 1000 * (1000/1024) / 8)
       *
       * The (1000/1024) was introduced in add_vif to optimize
       * this divide into a shift.
       */
      t->tbf_n_tok += tm * vifp->v_rate_limit / 1024 / 8;
      t->tbf_last_pkt_t = tp;
  
      if (t->tbf_n_tok > MAX_BKT_SIZE)
          t->tbf_n_tok = MAX_BKT_SIZE;
  
      splx(s);
  }
  
  static int
  priority(struct vif *vifp, struct ip *ip)
  {
      int prio = 50; /* the lowest priority -- default case */
  
      /* temporary hack; may add general packet classifier some day */
  
      /*
       * The UDP port space is divided up into four priority ranges:
       * [0, 16384)     : unclassified - lowest priority
       * [16384, 32768) : audio - highest priority
       * [32768, 49152) : whiteboard - medium priority
       * [49152, 65536) : video - low priority
       *
       * Everything else gets lowest priority.
       */
      if (ip->ip_p == IPPROTO_UDP) {
          struct udphdr *udp = (struct udphdr *)(((char *)ip) + (ip->ip_hl << 2));
          switch (ntohs(udp->uh_dport) & 0xc000) {
          case 0x4000:
              prio = 70;
              break;
          case 0x8000:
              prio = 60;
              break;
          case 0xc000:
              prio = 55;
              break;
          }
      }
      return prio;
  }
  
  /*
   * End of token bucket filter modifications
   */
  
  static int
  X_ip_rsvp_vif(struct socket *so, struct sockopt *sopt)
  {
      int error, vifi, s;
  
      if (so->so_type != SOCK_RAW || so->so_proto->pr_protocol != IPPROTO_RSVP)
          return EOPNOTSUPP;
  
      error = sooptcopyin(sopt, &vifi, sizeof vifi, sizeof vifi);
      if (error)
          return error;
  
      s = splnet();
  
      if (vifi < 0 || vifi >= numvifs) { /* Error if vif is invalid */
          splx(s);
          return EADDRNOTAVAIL;
      }
  
      if (sopt->sopt_name == IP_RSVP_VIF_ON) {
          /* Check if socket is available. */
          if (viftable[vifi].v_rsvpd != NULL) {
              splx(s);
              return EADDRINUSE;
          }
  
          viftable[vifi].v_rsvpd = so;
          /* This may seem silly, but we need to be sure we don't over-increment
           * the RSVP counter, in case something slips up.
           */
          if (!viftable[vifi].v_rsvp_on) {
              viftable[vifi].v_rsvp_on = 1;
              rsvp_on++;
          }
      } else { /* must be VIF_OFF */
          /*
           * XXX as an additional consistency check, one could make sure
           * that viftable[vifi].v_rsvpd == so, otherwise passing so as
           * first parameter is pretty useless.
           */
          viftable[vifi].v_rsvpd = NULL;
          /*
           * This may seem silly, but we need to be sure we don't over-decrement
           * the RSVP counter, in case something slips up.
           */
          if (viftable[vifi].v_rsvp_on) {
              viftable[vifi].v_rsvp_on = 0;
              rsvp_on--;
          }
      }
      splx(s);
      return 0;
  }
  
  static void
  X_ip_rsvp_force_done(struct socket *so)
  {
      int vifi;
      int s;
  
      /* Don't bother if it is not the right type of socket. */
      if (so->so_type != SOCK_RAW || so->so_proto->pr_protocol != IPPROTO_RSVP)
          return;
  
      s = splnet();
  
      /* The socket may be attached to more than one vif...this
       * is perfectly legal.
       */
      for (vifi = 0; vifi < numvifs; vifi++) {
          if (viftable[vifi].v_rsvpd == so) {
              viftable[vifi].v_rsvpd = NULL;
              /* This may seem silly, but we need to be sure we don't
               * over-decrement the RSVP counter, in case something slips up.
               */
              if (viftable[vifi].v_rsvp_on) {
                  viftable[vifi].v_rsvp_on = 0;
                  rsvp_on--;
              }
          }
      }
  
      splx(s);
  }
  
  static void
  X_rsvp_input(struct mbuf *m, int off, int proto)
  {
      int vifi;
      struct ip *ip = mtod(m, struct ip *);
      struct sockaddr_in rsvp_src = { sizeof rsvp_src, AF_INET };
      int s;
      struct ifnet *ifp;
  
      if (rsvpdebug)
          printf("rsvp_input: rsvp_on %d\n",rsvp_on);
  
      /* Can still get packets with rsvp_on = 0 if there is a local member
       * of the group to which the RSVP packet is addressed.  But in this
       * case we want to throw the packet away.
       */
      if (!rsvp_on) {
          m_freem(m);
          return;
      }
  
      s = splnet();
  
      if (rsvpdebug)
          printf("rsvp_input: check vifs\n");
  
  #ifdef DIAGNOSTIC
      if (!(m->m_flags & M_PKTHDR))
          panic("rsvp_input no hdr");
  #endif
  
      ifp = m->m_pkthdr.rcvif;
      /* Find which vif the packet arrived on. */
      for (vifi = 0; vifi < numvifs; vifi++)
          if (viftable[vifi].v_ifp == ifp)
              break;
  
      if (vifi == numvifs || viftable[vifi].v_rsvpd == NULL) {
          /*
           * If the old-style non-vif-associated socket is set,
           * then use it.  Otherwise, drop packet since there
           * is no specific socket for this vif.
           */
          if (ip_rsvpd != NULL) {
              if (rsvpdebug)
                  printf("rsvp_input: Sending packet up old-style socket\n");
              rip_input(m, off, proto);  /* xxx */
          } else {
              if (rsvpdebug && vifi == numvifs)
                  printf("rsvp_input: Can't find vif for packet.\n");
              else if (rsvpdebug && viftable[vifi].v_rsvpd == NULL)
                  printf("rsvp_input: No socket defined for vif %d\n",vifi);
              m_freem(m);
          }
          splx(s);
          return;
      }
      rsvp_src.sin_addr = ip->ip_src;
  
      if (rsvpdebug && m)
          printf("rsvp_input: m->m_len = %d, sbspace() = %ld\n",
                 m->m_len,sbspace(&(viftable[vifi].v_rsvpd->so_rcv)));
  
      if (socket_send(viftable[vifi].v_rsvpd, m, &rsvp_src) < 0) {
          if (rsvpdebug)
              printf("rsvp_input: Failed to append to socket\n");
      } else {
          if (rsvpdebug)
              printf("rsvp_input: send packet up\n");
      }
  
      splx(s);
  }
  
  /*
   * Code for bandwidth monitors
   */
  
  /*
   * Define common interface for timeval-related methods
   */
  #define BW_TIMEVALCMP(tvp, uvp, cmp) timevalcmp((tvp), (uvp), cmp)
  #define BW_TIMEVALDECR(vvp, uvp) timevalsub((vvp), (uvp))
  #define BW_TIMEVALADD(vvp, uvp) timevaladd((vvp), (uvp))
  
  static uint32_t
  compute_bw_meter_flags(struct bw_upcall *req)
  {
      uint32_t flags = 0;
  
      if (req->bu_flags & BW_UPCALL_UNIT_PACKETS)
          flags |= BW_METER_UNIT_PACKETS;
      if (req->bu_flags & BW_UPCALL_UNIT_BYTES)
          flags |= BW_METER_UNIT_BYTES;
      if (req->bu_flags & BW_UPCALL_GEQ)
          flags |= BW_METER_GEQ;
      if (req->bu_flags & BW_UPCALL_LEQ)
          flags |= BW_METER_LEQ;
      
      return flags;
  }
   
  /*
   * Add a bw_meter entry
   */
  static int
  add_bw_upcall(struct bw_upcall *req)
  {
      struct mfc *mfc;
      struct timeval delta = { BW_UPCALL_THRESHOLD_INTERVAL_MIN_SEC,
                  BW_UPCALL_THRESHOLD_INTERVAL_MIN_USEC };
      struct timeval now;
      struct bw_meter *x;
      uint32_t flags;
      int s;
      
      if (!(mrt_api_config & MRT_MFC_BW_UPCALL))
          return EOPNOTSUPP;
      
      /* Test if the flags are valid */
      if (!(req->bu_flags & (BW_UPCALL_UNIT_PACKETS | BW_UPCALL_UNIT_BYTES)))
          return EINVAL;
      if (!(req->bu_flags & (BW_UPCALL_GEQ | BW_UPCALL_LEQ)))
          return EINVAL;
      if ((req->bu_flags & (BW_UPCALL_GEQ | BW_UPCALL_LEQ))
              == (BW_UPCALL_GEQ | BW_UPCALL_LEQ))
          return EINVAL;
      
      /* Test if the threshold time interval is valid */
      if (BW_TIMEVALCMP(&req->bu_threshold.b_time, &delta, <))
          return EINVAL;
      
      flags = compute_bw_meter_flags(req);
  
      /*
       * Find if we have already same bw_meter entry
       */
      s = splnet();
      mfc = mfc_find(req->bu_src.s_addr, req->bu_dst.s_addr);
      if (mfc == NULL) {
          splx(s);
          return EADDRNOTAVAIL;
      }
      for (x = mfc->mfc_bw_meter; x != NULL; x = x->bm_mfc_next) {
          if ((BW_TIMEVALCMP(&x->bm_threshold.b_time,
                             &req->bu_threshold.b_time, ==)) &&
              (x->bm_threshold.b_packets == req->bu_threshold.b_packets) &&
              (x->bm_threshold.b_bytes == req->bu_threshold.b_bytes) &&
              (x->bm_flags & BW_METER_USER_FLAGS) == flags)  {
              splx(s);
              return 0;           /* XXX Already installed */
          }
      }
      splx(s);
      
      /* Allocate the new bw_meter entry */
      x = (struct bw_meter *)malloc(sizeof(*x), M_BWMETER, M_NOWAIT);
      if (x == NULL)
          return ENOBUFS;
      
      /* Set the new bw_meter entry */
      x->bm_threshold.b_time = req->bu_threshold.b_time;
      GET_TIME(now);
      x->bm_start_time = now;
      x->bm_threshold.b_packets = req->bu_threshold.b_packets;
      x->bm_threshold.b_bytes = req->bu_threshold.b_bytes;
      x->bm_measured.b_packets = 0;
      x->bm_measured.b_bytes = 0;
      x->bm_flags = flags;
      x->bm_time_next = NULL;
      x->bm_time_hash = BW_METER_BUCKETS;
      
      /* Add the new bw_meter entry to the front of entries for this MFC */
      s = splnet();
      x->bm_mfc = mfc;
      x->bm_mfc_next = mfc->mfc_bw_meter;
      mfc->mfc_bw_meter = x;
      schedule_bw_meter(x, &now);
      splx(s);
      
      return 0;
  }
  
  static void
  free_bw_list(struct bw_meter *list)
  {
      while (list != NULL) {
          struct bw_meter *x = list;
  
          list = list->bm_mfc_next;
          unschedule_bw_meter(x);
          free(x, M_BWMETER);
      }
  }
  
  /*
   * Delete one or multiple bw_meter entries
   */
  static int
  del_bw_upcall(struct bw_upcall *req)
  {
      struct mfc *mfc;
      struct bw_meter *x;
      int s;
      
      if (!(mrt_api_config & MRT_MFC_BW_UPCALL))
          return EOPNOTSUPP;
      
      s = splnet();
      /* Find the corresponding MFC entry */
      mfc = mfc_find(req->bu_src.s_addr, req->bu_dst.s_addr);
      if (mfc == NULL) {
          splx(s);
          return EADDRNOTAVAIL;
      } else if (req->bu_flags & BW_UPCALL_DELETE_ALL) {
          /*
           * Delete all bw_meter entries for this mfc
           */
          struct bw_meter *list;
          
          list = mfc->mfc_bw_meter;
          mfc->mfc_bw_meter = NULL;
          splx(s);
          free_bw_list(list);
          return 0;
      } else {                    /* Delete a single bw_meter entry */
          struct bw_meter *prev;
          uint32_t flags = 0;
  
          flags = compute_bw_meter_flags(req);
  
          /* Find the bw_meter entry to delete */
          for (prev = NULL, x = mfc->mfc_bw_meter; x != NULL;
               prev = x, x = x->bm_mfc_next) {
              if ((BW_TIMEVALCMP(&x->bm_threshold.b_time,
                                 &req->bu_threshold.b_time, ==)) &&
                  (x->bm_threshold.b_packets == req->bu_threshold.b_packets) &&
                  (x->bm_threshold.b_bytes == req->bu_threshold.b_bytes) &&
                  (x->bm_flags & BW_METER_USER_FLAGS) == flags)
                  break;
          }
          if (x != NULL) { /* Delete entry from the list for this MFC */
              if (prev != NULL)
                  prev->bm_mfc_next = x->bm_mfc_next;     /* remove from middle*/
              else
                  x->bm_mfc->mfc_bw_meter = x->bm_mfc_next;/* new head of list */
              splx(s);
  
              unschedule_bw_meter(x);
              /* Free the bw_meter entry */
              free(x, M_BWMETER);
              return 0;
          } else {
              splx(s);
              return EINVAL;
          }
      }
      /* NOTREACHED */
  }
  
  /*
   * Perform bandwidth measurement processing that may result in an upcall
   */
  static void
  bw_meter_receive_packet(struct bw_meter *x, int plen, struct timeval *nowp)
  {
      struct timeval delta;
      int s;
      
      s = splnet();
      delta = *nowp;
      BW_TIMEVALDECR(&delta, &x->bm_start_time);
      
      if (x->bm_flags & BW_METER_GEQ) {
          /*
           * Processing for ">=" type of bw_meter entry
           */
          if (BW_TIMEVALCMP(&delta, &x->bm_threshold.b_time, >)) {
              /* Reset the bw_meter entry */
              x->bm_start_time = *nowp;
              x->bm_measured.b_packets = 0;
              x->bm_measured.b_bytes = 0;
              x->bm_flags &= ~BW_METER_UPCALL_DELIVERED;
          }
          
          /* Record that a packet is received */
          x->bm_measured.b_packets++;
          x->bm_measured.b_bytes += plen;
          
          /*
           * Test if we should deliver an upcall
           */
          if (!(x->bm_flags & BW_METER_UPCALL_DELIVERED)) {       
              if (((x->bm_flags & BW_METER_UNIT_PACKETS) &&
                   (x->bm_measured.b_packets >= x->bm_threshold.b_packets)) ||
                  ((x->bm_flags & BW_METER_UNIT_BYTES) &&
                   (x->bm_measured.b_bytes >= x->bm_threshold.b_bytes))) {
                  /* Prepare an upcall for delivery */
                  bw_meter_prepare_upcall(x, nowp);
                  x->bm_flags |= BW_METER_UPCALL_DELIVERED;
              }
          }
      } else if (x->bm_flags & BW_METER_LEQ) {
          /*
           * Processing for "<=" type of bw_meter entry
           */
          if (BW_TIMEVALCMP(&delta, &x->bm_threshold.b_time, >)) {
              /*
               * We are behind time with the multicast forwarding table
               * scanning for "<=" type of bw_meter entries, so test now
               * if we should deliver an upcall.
               */
              if (((x->bm_flags & BW_METER_UNIT_PACKETS) &&
                   (x->bm_measured.b_packets <= x->bm_threshold.b_packets)) ||
                  ((x->bm_flags & BW_METER_UNIT_BYTES) &&
                   (x->bm_measured.b_bytes <= x->bm_threshold.b_bytes))) {
                  /* Prepare an upcall for delivery */
                  bw_meter_prepare_upcall(x, nowp);
              }
              /* Reschedule the bw_meter entry */
              unschedule_bw_meter(x);
              schedule_bw_meter(x, nowp);
          }
          
          /* Record that a packet is received */
          x->bm_measured.b_packets++;
          x->bm_measured.b_bytes += plen;
          
          /*
           * Test if we should restart the measuring interval
           */
          if ((x->bm_flags & BW_METER_UNIT_PACKETS &&
               x->bm_measured.b_packets <= x->bm_threshold.b_packets) ||
              (x->bm_flags & BW_METER_UNIT_BYTES &&
               x->bm_measured.b_bytes <= x->bm_threshold.b_bytes)) {
              /* Don't restart the measuring interval */
          } else {
              /* Do restart the measuring interval */
              /*
               * XXX: note that we don't unschedule and schedule, because this
               * might be too much overhead per packet. Instead, when we process
               * all entries for a given timer hash bin, we check whether it is
               * really a timeout. If not, we reschedule at that time.
               */
              x->bm_start_time = *nowp;
              x->bm_measured.b_packets = 0;
              x->bm_measured.b_bytes = 0;
              x->bm_flags &= ~BW_METER_UPCALL_DELIVERED;
          }
      }
      splx(s);
  }
  
  /*
   * Prepare a bandwidth-related upcall
   */
  static void
  bw_meter_prepare_upcall(struct bw_meter *x, struct timeval *nowp)
  {
      struct timeval delta;
      struct bw_upcall *u;
      int s;
      
      s = splnet();
      
      /*
       * Compute the measured time interval 
       */
      delta = *nowp;
      BW_TIMEVALDECR(&delta, &x->bm_start_time);
      
      /*
       * If there are too many pending upcalls, deliver them now
       */
      if (bw_upcalls_n >= BW_UPCALLS_MAX)
          bw_upcalls_send();
      
      /*
       * Set the bw_upcall entry
       */
      u = &bw_upcalls[bw_upcalls_n++];
      u->bu_src = x->bm_mfc->mfc_origin;
      u->bu_dst = x->bm_mfc->mfc_mcastgrp;
      u->bu_threshold.b_time = x->bm_threshold.b_time;
      u->bu_threshold.b_packets = x->bm_threshold.b_packets;
      u->bu_threshold.b_bytes = x->bm_threshold.b_bytes;
      u->bu_measured.b_time = delta;
      u->bu_measured.b_packets = x->bm_measured.b_packets;
      u->bu_measured.b_bytes = x->bm_measured.b_bytes;
      u->bu_flags = 0;
      if (x->bm_flags & BW_METER_UNIT_PACKETS)
          u->bu_flags |= BW_UPCALL_UNIT_PACKETS;
      if (x->bm_flags & BW_METER_UNIT_BYTES)
          u->bu_flags |= BW_UPCALL_UNIT_BYTES;
      if (x->bm_flags & BW_METER_GEQ)
          u->bu_flags |= BW_UPCALL_GEQ;
      if (x->bm_flags & BW_METER_LEQ)
          u->bu_flags |= BW_UPCALL_LEQ;
      
      splx(s);
  }
  
  /*
   * Send the pending bandwidth-related upcalls
   */
  static void
  bw_upcalls_send(void)
  {
      struct mbuf *m;
      int len = bw_upcalls_n * sizeof(bw_upcalls[0]);
      struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };
      static struct igmpmsg igmpmsg = { 0,                /* unused1 */
                                        0,                /* unused2 */
                                        IGMPMSG_BW_UPCALL,/* im_msgtype */
                                        0,                /* im_mbz  */
                                        0,                /* im_vif  */
                                        0,                /* unused3 */
                                        { 0 },            /* im_src  */
                                        { 0 } };          /* im_dst  */
      
      if (bw_upcalls_n == 0)
          return;                 /* No pending upcalls */
  
      bw_upcalls_n = 0;
      
      /*
       * Allocate a new mbuf, initialize it with the header and
       * the payload for the pending calls.
       */
      MGETHDR(m, M_DONTWAIT, MT_HEADER);
      if (m == NULL) {
          log(LOG_WARNING, "bw_upcalls_send: cannot allocate mbuf\n");
          return;
      }
      
      m->m_len = m->m_pkthdr.len = 0;
      m_copyback(m, 0, sizeof(struct igmpmsg), (caddr_t)&igmpmsg);
      m_copyback(m, sizeof(struct igmpmsg), len, (caddr_t)&bw_upcalls[0]);
      
      /*
       * Send the upcalls
       * XXX do we need to set the address in k_igmpsrc ?
       */
      mrtstat.mrts_upcalls++;
      if (socket_send(ip_mrouter, m, &k_igmpsrc) < 0) {
          log(LOG_WARNING, "bw_upcalls_send: ip_mrouter socket queue full\n");
          ++mrtstat.mrts_upq_sockfull;
      }
  }
  
  /*
   * Compute the timeout hash value for the bw_meter entries
   */
  #define BW_METER_TIMEHASH(bw_meter, hash)                               \
      do {                                                                \
          struct timeval next_timeval = (bw_meter)->bm_start_time;        \
                                                                          \
          BW_TIMEVALADD(&next_timeval, &(bw_meter)->bm_threshold.b_time); \
          (hash) = next_timeval.tv_sec;                                   \
          if (next_timeval.tv_usec)                                       \
              (hash)++; /* XXX: make sure we don't timeout early */       \
          (hash) %= BW_METER_BUCKETS;                                     \
      } while (0)
  
  /*
   * Schedule a timer to process periodically bw_meter entry of type "<="
   * by linking the entry in the proper hash bucket.
   */
  static void
  schedule_bw_meter(struct bw_meter *x, struct timeval *nowp)
  {
      int time_hash, s;
      
      if (!(x->bm_flags & BW_METER_LEQ))
          return;         /* XXX: we schedule timers only for "<=" entries */
      
      /*
       * Reset the bw_meter entry
       */
      s = splnet();
      x->bm_start_time = *nowp;
      x->bm_measured.b_packets = 0;
      x->bm_measured.b_bytes = 0;
      x->bm_flags &= ~BW_METER_UPCALL_DELIVERED;
      splx(s);
      
      /*
       * Compute the timeout hash value and insert the entry
       */
      BW_METER_TIMEHASH(x, time_hash);
      x->bm_time_next = bw_meter_timers[time_hash];
      bw_meter_timers[time_hash] = x;
      x->bm_time_hash = time_hash;
  }
  
  /*
   * Unschedule the periodic timer that processes bw_meter entry of type "<="
   * by removing the entry from the proper hash bucket.
   */
  static void
  unschedule_bw_meter(struct bw_meter *x)
  {
      int time_hash;
      struct bw_meter *prev, *tmp;
      
      if (!(x->bm_flags & BW_METER_LEQ))
          return;         /* XXX: we schedule timers only for "<=" entries */
      
      /*
       * Compute the timeout hash value and delete the entry
       */
      time_hash = x->bm_time_hash;
      if (time_hash >= BW_METER_BUCKETS)
          return;         /* Entry was not scheduled */
      
      for (prev = NULL, tmp = bw_meter_timers[time_hash];
               tmp != NULL; prev = tmp, tmp = tmp->bm_time_next)
          if (tmp == x)
              break;
      
      if (tmp == NULL)
          panic("unschedule_bw_meter: bw_meter entry not found");
      
      if (prev != NULL)
          prev->bm_time_next = x->bm_time_next;
      else
          bw_meter_timers[time_hash] = x->bm_time_next;
      
      x->bm_time_next = NULL;
      x->bm_time_hash = BW_METER_BUCKETS;
  }
  
  
  /*
   * Process all "<=" type of bw_meter that should be processed now,
   * and for each entry prepare an upcall if necessary. Each processed
   * entry is rescheduled again for the (periodic) processing.
   *
   * This is run periodically (once per second normally). On each round,
   * all the potentially matching entries are in the hash slot that we are
   * looking at.
   */
  static void
  bw_meter_process()
  {
      static uint32_t last_tv_sec;        /* last time we processed this */
  
      uint32_t loops;
      int i, s;
      struct timeval now, process_endtime;
      
      GET_TIME(now);
      if (last_tv_sec == now.tv_sec)
          return;         /* nothing to do */
  
      s = splnet();
      loops = now.tv_sec - last_tv_sec;
      last_tv_sec = now.tv_sec;
      if (loops > BW_METER_BUCKETS)
          loops = BW_METER_BUCKETS;
  
      /*
       * Process all bins of bw_meter entries from the one after the last
       * processed to the current one. On entry, i points to the last bucket
       * visited, so we need to increment i at the beginning of the loop.
       */
      for (i = (now.tv_sec - loops) % BW_METER_BUCKETS; loops > 0; loops--) {
          struct bw_meter *x, *tmp_list;
          
          if (++i >= BW_METER_BUCKETS)
              i = 0;
          
          /* Disconnect the list of bw_meter entries from the bin */
          tmp_list = bw_meter_timers[i];
          bw_meter_timers[i] = NULL;
          
          /* Process the list of bw_meter entries */
          while (tmp_list != NULL) {
              x = tmp_list;
              tmp_list = tmp_list->bm_time_next;
              
              /* Test if the time interval is over */
              process_endtime = x->bm_start_time;
              BW_TIMEVALADD(&process_endtime, &x->bm_threshold.b_time);
              if (BW_TIMEVALCMP(&process_endtime, &now, >)) {
                  /* Not yet: reschedule, but don't reset */
                  int time_hash;
                  
                  BW_METER_TIMEHASH(x, time_hash);
                  if (time_hash == i && process_endtime.tv_sec == now.tv_sec) {
                      /*
                       * XXX: somehow the bin processing is a bit ahead of time.
                       * Put the entry in the next bin.
                       */
                      if (++time_hash >= BW_METER_BUCKETS)
                          time_hash = 0;
                  }
                  x->bm_time_next = bw_meter_timers[time_hash];
                  bw_meter_timers[time_hash] = x;
                  x->bm_time_hash = time_hash;
                  
                  continue;
              }
              
              /*
               * Test if we should deliver an upcall
               */
              if (((x->bm_flags & BW_METER_UNIT_PACKETS) &&
                   (x->bm_measured.b_packets <= x->bm_threshold.b_packets)) ||
                  ((x->bm_flags & BW_METER_UNIT_BYTES) &&
                   (x->bm_measured.b_bytes <= x->bm_threshold.b_bytes))) {
                  /* Prepare an upcall for delivery */
                  bw_meter_prepare_upcall(x, &now);
              }
              
              /*
               * Reschedule for next processing
               */
              schedule_bw_meter(x, &now);
          }
      }
      splx(s);
      
      /* Send all upcalls that are pending delivery */
      bw_upcalls_send();
  }
  
  /*
   * A periodic function for sending all upcalls that are pending delivery
   */
  static void
  expire_bw_upcalls_send(void *unused)
  {
      bw_upcalls_send();
      
      bw_upcalls_ch = timeout(expire_bw_upcalls_send, NULL, BW_UPCALLS_PERIOD);
  }
  
  /*
   * A periodic function for periodic scanning of the multicast forwarding
   * table for processing all "<=" bw_meter entries.
   */
  static void
  expire_bw_meter_process(void *unused)
  {
      if (mrt_api_config & MRT_MFC_BW_UPCALL)
          bw_meter_process();
      
      bw_meter_ch = timeout(expire_bw_meter_process, NULL, BW_METER_PERIOD);
  }
  
  /*
   * End of bandwidth monitoring code
   */
  
  #ifdef PIM
  /*
   * Send the packet up to the user daemon, or eventually do kernel encapsulation
   *
   */
  static int
  pim_register_send(struct ip *ip, struct vif *vifp,
          struct mbuf *m, struct mfc *rt)
  {
      struct mbuf *mb_copy, *mm;
      
      if (mrtdebug & DEBUG_PIM)
          log(LOG_DEBUG, "pim_register_send: ");
      
      mb_copy = pim_register_prepare(ip, m);
      if (mb_copy == NULL)
          return ENOBUFS;
      
      /*
       * Send all the fragments. Note that the mbuf for each fragment
       * is freed by the sending machinery.
       */
      for (mm = mb_copy; mm; mm = mb_copy) {
          mb_copy = mm->m_nextpkt;
          mm->m_nextpkt = 0;
          mm = m_pullup(mm, sizeof(struct ip));
          if (mm != NULL) {
              ip = mtod(mm, struct ip *);
              if ((mrt_api_config & MRT_MFC_RP) &&
                  (rt->mfc_rp.s_addr != INADDR_ANY)) {
                  pim_register_send_rp(ip, vifp, mm, rt);
              } else {
                  pim_register_send_upcall(ip, vifp, mm, rt);
              }
          }
      }
      
      return 0;
  }
  
  /*
   * Return a copy of the data packet that is ready for PIM Register
   * encapsulation.
   * XXX: Note that in the returned copy the IP header is a valid one.
   */
  static struct mbuf *
  pim_register_prepare(struct ip *ip, struct mbuf *m)
  {
      struct mbuf *mb_copy = NULL;
      int mtu;
      
      /* Take care of delayed checksums */
      if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
          in_delayed_cksum(m);
          m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
      }
  
      /*
       * Copy the old packet & pullup its IP header into the
       * new mbuf so we can modify it.
       */
      mb_copy = m_copypacket(m, M_DONTWAIT);
      if (mb_copy == NULL)
          return NULL;
      mb_copy = m_pullup(mb_copy, ip->ip_hl << 2);
      if (mb_copy == NULL)
          return NULL;
      
      /* take care of the TTL */
      ip = mtod(mb_copy, struct ip *);
      --ip->ip_ttl;
      
      /* Compute the MTU after the PIM Register encapsulation */
      mtu = 0xffff - sizeof(pim_encap_iphdr) - sizeof(pim_encap_pimhdr);
      
      if (ip->ip_len <= mtu) {
          /* Turn the IP header into a valid one */
          ip->ip_len = htons(ip->ip_len);
          ip->ip_off = htons(ip->ip_off);
          ip->ip_sum = 0;
          ip->ip_sum = in_cksum(mb_copy, ip->ip_hl << 2);
      } else {
          /* Fragment the packet */
          if (ip_fragment(ip, &mb_copy, mtu, 0, CSUM_DELAY_IP) != 0) {
              m_freem(mb_copy);
              return NULL;
          }
      }
      return mb_copy;
  }
  
  /*
   * Send an upcall with the data packet to the user-level process.
   */
  static int
  pim_register_send_upcall(struct ip *ip, struct vif *vifp,
          struct mbuf *mb_copy, struct mfc *rt)
  {
      struct mbuf *mb_first;
      int len = ntohs(ip->ip_len);
      struct igmpmsg *im;
      struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };
      
      /*
       * Add a new mbuf with an upcall header
       */
      MGETHDR(mb_first, M_DONTWAIT, MT_HEADER);
      if (mb_first == NULL) {
          m_freem(mb_copy);
          return ENOBUFS;
      }
      mb_first->m_data += max_linkhdr;
      mb_first->m_pkthdr.len = len + sizeof(struct igmpmsg);
      mb_first->m_len = sizeof(struct igmpmsg);
      mb_first->m_next = mb_copy;
      
      /* Send message to routing daemon */
      im = mtod(mb_first, struct igmpmsg *);
      im->im_msgtype      = IGMPMSG_WHOLEPKT;
      im->im_mbz          = 0;
      im->im_vif          = vifp - viftable;
      im->im_src          = ip->ip_src;
      im->im_dst          = ip->ip_dst;
      
      k_igmpsrc.sin_addr  = ip->ip_src;
      
      mrtstat.mrts_upcalls++;
      
      if (socket_send(ip_mrouter, mb_first, &k_igmpsrc) < 0) {
          if (mrtdebug & DEBUG_PIM)
              log(LOG_WARNING,
                  "mcast: pim_register_send_upcall: ip_mrouter socket queue full");
          ++mrtstat.mrts_upq_sockfull;
          return ENOBUFS;
      }
      
      /* Keep statistics */
      pimstat.pims_snd_registers_msgs++;
      pimstat.pims_snd_registers_bytes += len;
      
      return 0;
  }
  
  /*
   * Encapsulate the data packet in PIM Register message and send it to the RP.
   */
  static int
  pim_register_send_rp(struct ip *ip, struct vif *vifp,
          struct mbuf *mb_copy, struct mfc *rt)
  {
      struct mbuf *mb_first;
      struct ip *ip_outer;
      struct pim_encap_pimhdr *pimhdr;
      int len = ntohs(ip->ip_len);
      vifi_t vifi = rt->mfc_parent;
      
      if ((vifi >= numvifs) || (viftable[vifi].v_lcl_addr.s_addr == 0)) {
          m_freem(mb_copy);
          return EADDRNOTAVAIL;           /* The iif vif is invalid */
      }
      
      /*
       * Add a new mbuf with the encapsulating header
       */
      MGETHDR(mb_first, M_DONTWAIT, MT_HEADER);
      if (mb_first == NULL) {
          m_freem(mb_copy);
          return ENOBUFS;
      }
      mb_first->m_data += max_linkhdr;
      mb_first->m_len = sizeof(pim_encap_iphdr) + sizeof(pim_encap_pimhdr);
      mb_first->m_next = mb_copy;
  
      mb_first->m_pkthdr.len = len + mb_first->m_len;
      
      /*
       * Fill in the encapsulating IP and PIM header
       */
      ip_outer = mtod(mb_first, struct ip *);
      *ip_outer = pim_encap_iphdr;
  #ifdef RANDOM_IP_ID
      ip_outer->ip_id = ip_randomid();
  #else
      ip_outer->ip_id = htons(ip_id++);
  #endif
      ip_outer->ip_len = len + sizeof(pim_encap_iphdr) + sizeof(pim_encap_pimhdr);
      ip_outer->ip_src = viftable[vifi].v_lcl_addr;
      ip_outer->ip_dst = rt->mfc_rp;
      /*
       * Copy the inner header TOS to the outer header, and take care of the
       * IP_DF bit.
       */
      ip_outer->ip_tos = ip->ip_tos;
      if (ntohs(ip->ip_off) & IP_DF)
          ip_outer->ip_off |= IP_DF;
      pimhdr = (struct pim_encap_pimhdr *)((caddr_t)ip_outer
                                           + sizeof(pim_encap_iphdr));
      *pimhdr = pim_encap_pimhdr;
      /* If the iif crosses a border, set the Border-bit */
      if (rt->mfc_flags[vifi] & MRT_MFC_FLAGS_BORDER_VIF & mrt_api_config)
          pimhdr->flags |= htonl(PIM_BORDER_REGISTER);
      
      mb_first->m_data += sizeof(pim_encap_iphdr);
      pimhdr->pim.pim_cksum = in_cksum(mb_first, sizeof(pim_encap_pimhdr));
      mb_first->m_data -= sizeof(pim_encap_iphdr);
      
      if (vifp->v_rate_limit == 0)
          tbf_send_packet(vifp, mb_first);
      else
          tbf_control(vifp, mb_first, ip, ip_outer->ip_len);
      
      /* Keep statistics */
      pimstat.pims_snd_registers_msgs++;
      pimstat.pims_snd_registers_bytes += len;
      
      return 0;
  }
  
  /*
   * PIM-SMv2 and PIM-DM messages processing.
   * Receives and verifies the PIM control messages, and passes them
   * up to the listening socket, using rip_input().
   * The only message with special processing is the PIM_REGISTER message
   * (used by PIM-SM): the PIM header is stripped off, and the inner packet
   * is passed to if_simloop().
   */
  void
  pim_input(struct mbuf *m, int off, int proto)
  {
      struct ip *ip = mtod(m, struct ip *);
      struct pim *pim;
      int minlen;
      int datalen = ip->ip_len;
      int ip_tos;
      int iphlen = off;
      
      /* Keep statistics */
      pimstat.pims_rcv_total_msgs++;
      pimstat.pims_rcv_total_bytes += datalen;
      
      /*
       * Validate lengths
       */
      if (datalen < PIM_MINLEN) {
          pimstat.pims_rcv_tooshort++;
          log(LOG_ERR, "pim_input: packet size too small %d from %lx\n",
              datalen, (u_long)ip->ip_src.s_addr);
          m_freem(m);
          return;
      }
      
      /*
       * If the packet is at least as big as a REGISTER, go agead
       * and grab the PIM REGISTER header size, to avoid another
       * possible m_pullup() later.
       * 
       * PIM_MINLEN       == pimhdr + u_int32_t == 4 + 4 = 8
       * PIM_REG_MINLEN   == pimhdr + reghdr + encap_iphdr == 4 + 4 + 20 = 28
       */
      minlen = iphlen + (datalen >= PIM_REG_MINLEN ? PIM_REG_MINLEN : PIM_MINLEN);
      /*
       * Get the IP and PIM headers in contiguous memory, and
       * possibly the PIM REGISTER header.
       */
      if ((m->m_flags & M_EXT || m->m_len < minlen) &&
          (m = m_pullup(m, minlen)) == 0) {
          log(LOG_ERR, "pim_input: m_pullup failure\n");
          return;
      }
      /* m_pullup() may have given us a new mbuf so reset ip. */
      ip = mtod(m, struct ip *);
      ip_tos = ip->ip_tos;
      
      /* adjust mbuf to point to the PIM header */
      m->m_data += iphlen;
      m->m_len  -= iphlen;
      pim = mtod(m, struct pim *);
      
      /*
       * Validate checksum. If PIM REGISTER, exclude the data packet.
       *
       * XXX: some older PIMv2 implementations don't make this distinction,
       * so for compatibility reason perform the checksum over part of the
       * message, and if error, then over the whole message.
       */
      if (PIM_VT_T(pim->pim_vt) == PIM_REGISTER && in_cksum(m, PIM_MINLEN) == 0) {
          /* do nothing, checksum okay */
      } else if (in_cksum(m, datalen)) {
          pimstat.pims_rcv_badsum++;
          if (mrtdebug & DEBUG_PIM)
              log(LOG_DEBUG, "pim_input: invalid checksum");
          m_freem(m);
          return;
      }
  
      /* PIM version check */
      if (PIM_VT_V(pim->pim_vt) < PIM_VERSION) {
          pimstat.pims_rcv_badversion++;
          log(LOG_ERR, "pim_input: incorrect version %d, expecting %d\n",
              PIM_VT_V(pim->pim_vt), PIM_VERSION);
          m_freem(m);
          return;
      }
      
      /* restore mbuf back to the outer IP */
      m->m_data -= iphlen;
      m->m_len  += iphlen;
      
      if (PIM_VT_T(pim->pim_vt) == PIM_REGISTER) {
          /*
           * Since this is a REGISTER, we'll make a copy of the register
           * headers ip + pim + u_int32 + encap_ip, to be passed up to the
           * routing daemon.
           */
          struct sockaddr_in dst = { sizeof(dst), AF_INET };
          struct mbuf *mcp;
          struct ip *encap_ip;
          u_int32_t *reghdr;
          
          if ((reg_vif_num >= numvifs) || (reg_vif_num == VIFI_INVALID)) {
              if (mrtdebug & DEBUG_PIM)
                  log(LOG_DEBUG,
                      "pim_input: register vif not set: %d\n", reg_vif_num);
              m_freem(m);
              return;
          }
          
          /*
           * Validate length
           */
          if (datalen < PIM_REG_MINLEN) {
              pimstat.pims_rcv_tooshort++;
              pimstat.pims_rcv_badregisters++;
              log(LOG_ERR,
                  "pim_input: register packet size too small %d from %lx\n",
                  datalen, (u_long)ip->ip_src.s_addr);
              m_freem(m);
              return;
          }
          
          reghdr = (u_int32_t *)(pim + 1);
          encap_ip = (struct ip *)(reghdr + 1);
          
          if (mrtdebug & DEBUG_PIM) {
              log(LOG_DEBUG,
                  "pim_input[register], encap_ip: %lx -> %lx, encap_ip len %d\n",
                  (u_long)ntohl(encap_ip->ip_src.s_addr),
                  (u_long)ntohl(encap_ip->ip_dst.s_addr),
                  ntohs(encap_ip->ip_len));
          }
          
          /* verify the version number of the inner packet */
          if (encap_ip->ip_v != IPVERSION) {
              pimstat.pims_rcv_badregisters++;
              if (mrtdebug & DEBUG_PIM) {
                  log(LOG_DEBUG, "pim_input: invalid IP version (%d) "
                      "of the inner packet\n", encap_ip->ip_v);
              }
              m_freem(m);
              return;
          }
          
          /* verify the inner packet is destined to a mcast group */
          if (!IN_MULTICAST(ntohl(encap_ip->ip_dst.s_addr))) {
              pimstat.pims_rcv_badregisters++;
              if (mrtdebug & DEBUG_PIM)
                  log(LOG_DEBUG,
                      "pim_input: inner packet of register is not "
                      "multicast %lx\n",
                      (u_long)ntohl(encap_ip->ip_dst.s_addr));
              m_freem(m);
              return;
          }
          
          /*
           * Copy the TOS from the outer IP header to the inner IP header.
           */
          if (encap_ip->ip_tos != ip_tos) {
              /* Outer TOS -> inner TOS */
              encap_ip->ip_tos = ip_tos;
              /* Recompute the inner header checksum. Sigh... */
              
              /* adjust mbuf to point to the inner IP header */
              m->m_data += (iphlen + PIM_MINLEN);
              m->m_len  -= (iphlen + PIM_MINLEN);
              
              encap_ip->ip_sum = 0;
              encap_ip->ip_sum = in_cksum(m, encap_ip->ip_hl << 2);
              
              /* restore mbuf to point back to the outer IP header */
              m->m_data -= (iphlen + PIM_MINLEN);
              m->m_len  += (iphlen + PIM_MINLEN);
          }
          
          /* If a NULL_REGISTER, pass it to the daemon */
          if ((ntohl(*reghdr) & PIM_NULL_REGISTER))
              goto pim_input_to_daemon;
          
          /*
           * Decapsulate the inner IP packet and loopback to forward it
           * as a normal multicast packet. Also, make a copy of the 
           *     outer_iphdr + pimhdr + reghdr + encap_iphdr
           * to pass to the daemon later, so it can take the appropriate
           * actions (e.g., send back PIM_REGISTER_STOP).
           * XXX: here m->m_data points to the outer IP header.
           */
          mcp = m_copy(m, 0, iphlen + PIM_REG_MINLEN);
          if (mcp == NULL) {
              log(LOG_ERR,
                  "pim_input: pim register: could not copy register head\n");
              m_freem(m);
              return;
          }
          
          /* Keep statistics */
          /* XXX: registers_bytes include only the encap. mcast pkt */
          pimstat.pims_rcv_registers_msgs++;
          pimstat.pims_rcv_registers_bytes += ntohs(encap_ip->ip_len);
          
          /*
           * forward the inner ip packet; point m_data at the inner ip.
           */
          m_adj(m, iphlen + PIM_MINLEN);
          
          if (mrtdebug & DEBUG_PIM) {
              log(LOG_DEBUG,
                  "pim_input: forwarding decapsulated register: "
                  "src %lx, dst %lx, vif %d\n",
                  (u_long)ntohl(encap_ip->ip_src.s_addr),
                  (u_long)ntohl(encap_ip->ip_dst.s_addr),
                  reg_vif_num);
          }
          if_simloop(viftable[reg_vif_num].v_ifp, m, dst.sin_family, 0);
          
          /* prepare the register head to send to the mrouting daemon */
          m = mcp;
      }
  
  pim_input_to_daemon:    
      /*
       * Pass the PIM message up to the daemon; if it is a Register message,
       * pass the 'head' only up to the daemon. This includes the
       * outer IP header, PIM header, PIM-Register header and the
       * inner IP header.
       * XXX: the outer IP header pkt size of a Register is not adjust to
       * reflect the fact that the inner multicast data is truncated.
       */
      rip_input(m, iphlen, proto);
  
      return;
  }
  #endif /* PIM */
  
  static int
  ip_mroute_modevent(module_t mod, int type, void *unused)
  {
      int s;
  
      switch (type) {
      case MOD_LOAD:
          s = splnet();
          /* XXX Protect against multiple loading */
          ip_mcast_src = X_ip_mcast_src;
          ip_mforward = X_ip_mforward;
          ip_mrouter_done = X_ip_mrouter_done;
          ip_mrouter_get = X_ip_mrouter_get;
          ip_mrouter_set = X_ip_mrouter_set;
          ip_rsvp_force_done = X_ip_rsvp_force_done;
          ip_rsvp_vif = X_ip_rsvp_vif;
          ipip_input = X_ipip_input;
          legal_vif_num = X_legal_vif_num;
          mrt_ioctl = X_mrt_ioctl;
          rsvp_input_p = X_rsvp_input;
          splx(s);
          break;
  
      case MOD_UNLOAD:
          if (ip_mrouter)
              return EINVAL;
  
          s = splnet();
          ip_mcast_src = NULL;
          ip_mforward = NULL;
          ip_mrouter_done = NULL;
          ip_mrouter_get = NULL;
          ip_mrouter_set = NULL;
          ip_rsvp_force_done = NULL;
          ip_rsvp_vif = NULL;
          ipip_input = NULL;
          legal_vif_num = NULL;
          mrt_ioctl = NULL;
          rsvp_input_p = NULL;
          splx(s);
          break;
      }
      return 0;
  }
  
  static moduledata_t ip_mroutemod = {
      "ip_mroute",
      ip_mroute_modevent,
      0
  };
  DECLARE_MODULE(ip_mroute, ip_mroutemod, SI_SUB_PSEUDO, SI_ORDER_ANY);