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
     *
     * MROUTING Revision: 3.5
     * $FreeBSD: releng/5.1/sys/netinet/ip_mroute.c 113255 2003-04-08 14:25:47Z des $
     */
    
    #include "opt_mac.h"
    #include "opt_mrouting.h"
    #include "opt_random_ip_id.h"
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/mac.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/protosw.h>
    #include <sys/signalvar.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/sockio.h>
    #include <sys/sx.h>
    #include <sys/sysctl.h>
    #include <sys/syslog.h>
    #include <sys/systm.h>
    #include <sys/time.h>
    #include <net/if.h>
    #include <net/netisr.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_encap.h>
    #include <netinet/ip_mroute.h>
    #include <netinet/ip_var.h>
    #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 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];
    static u_char           nexpire[MFCTBLSIZ];
    static struct vif       viftable[MAXVIFS];
    
    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 */
   };
   
   /*
    * Private variables.
    */
   static vifi_t      numvifs;
   static const struct encaptab *encap_cookie;
   
   /*
    * one-back cache used by mroute_encapcheck 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 mfcctl *);
   static int del_mfc(struct mfcctl *);
   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 *);
   
   /*
    * 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
   
   /*
    * 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      mfcctl mfc;
   
       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:
           error = sooptcopyin(sopt, &mfc, sizeof mfc, sizeof mfc);
           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;
   
       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;
   
       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);
   
       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)) {
               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);
   
       /*
        * 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(rt, M_MRTABLE);
               rt = nr;
           }
       }
   
       bzero((caddr_t)mfctable, sizeof(mfctable));
   
       /*
        * Reset de-encapsulation cache
        */
       last_encap_src = INADDR_ANY;
       last_encap_vif = NULL;
       if (encap_cookie) {
           encap_detach(encap_cookie);
           encap_cookie = NULL;
       }
   
       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;
   }
   
   /*
    * Decide if a packet is from a tunnelled peer.
    * Return 0 if not, 64 if so.  XXX yuck.. 64 ???
    */
   static int
   mroute_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
   {
       struct ip *ip = mtod(m, struct ip *);
       int hlen = ip->ip_hl << 2;
   
       /*
        * don't claim 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)))
           return 0;
       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;
           return 0;
       }
       return 64;
   }
   
   /*
    * De-encapsulate a packet and feed it back through ip input (this
    * routine is called whenever IP gets a packet that mroute_encap_func()
    * claimed).
    */
   static void
   mroute_encap_input(struct mbuf *m, int off)
   {
       struct ip *ip = mtod(m, struct ip *);
       int hlen = ip->ip_hl << 2;
   
       if (hlen > sizeof(struct ip))
           ip_stripoptions(m, (struct mbuf *) 0);
       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;
   
       netisr_queue(NETISR_IP, 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.
        *
        * XXX
        * This no longer holds - we may have direct-dispatched the packet,
        * or there may be a queue processing limit.
        */
   }
   
   extern struct domain inetdomain;
   static struct protosw mroute_encap_protosw =
   { SOCK_RAW,     &inetdomain,    IPPROTO_IPV4,   PR_ATOMIC|PR_ADDR,
     mroute_encap_input,   0,      0,              rip_ctloutput,
     0,
     0,            0,              0,              0,
     &rip_usrreqs
   };
   
   /*
    * 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 */
       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
                * mroute_encap_input() to start paying attention
                * to encapsulated packets.
                */
               if (encap_cookie == NULL) {
                   encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV4,
                                   mroute_encapcheck,
                                   (struct protosw *)&mroute_encap_protosw, NULL);
   
                   if (encap_cookie == NULL) {
                       printf("ip_mroute: unable to attach encap\n");
                       return EIO; /* XXX */
                   }
                   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;
           }
       } 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))
           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);
       }
   
       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 mfcctl *mfccp)
   {
       int i;
   
       rt->mfc_parent = mfccp->mfcc_parent;
       for (i = 0; i < numvifs; i++)
           rt->mfc_ttls[i] = mfccp->mfcc_ttls[i];
   }
   
   /*
    * fully initialize an mfc entry from the parameter.
    */
   static void
   init_mfc_params(struct mfc *rt, struct mfcctl *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 mfcctl *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;
               
               /* 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 mfcctl *mfccp)
   {
       struct in_addr      origin;
       struct in_addr      mcastgrp;
       struct mfc          *rt;
       struct mfc          **nptr;
       u_long              hash;
       int s;
   
       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(rt, M_MRTABLE);
   
       splx(s);
   
       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.
            */
       } 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_copy(m, 0, M_COPYALL);
          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_parent = -1;
  
              /* 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]--;
  
                  *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) {
          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, and we are forwarding
           * packets on this interface, and it is a broadcast medium
           * interface (and not a tunnel), send a message to the routing daemon.
           */
          if (pim_assert && rt->mfc_ttls[vifi] &&
                  (ifp->if_flags & IFF_BROADCAST) &&
                  !(viftable[vifi].v_flags & VIFF_TUNNEL)) {
              struct timeval now;
              u_long delta;
  
              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;
  
                  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;
              MC_SEND(ip, viftable+vifi, m);
          }
  
      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_copy(m, 0, M_COPYALL);
      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;
  
      /*
       * XXX: take care of delayed checksums.
       * XXX: if network interfaces are capable of computing checksum for
       * encapsulated multicast data packets, we need to reconsider this.
       */
      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;
  #ifdef MAC
      mac_create_mbuf_multicast_encap(m, vifp->v_ifp, mb_copy);
  #endif
      mb_copy->m_data += max_linkhdr;
      mb_copy->m_len = sizeof(multicast_encap_iphdr);
  
      if ((mb_copy->m_next = m_copy(m, 0, M_COPYALL)) == 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);
  }
  
  /*
   * 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 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
      M_ASSERTPKTHDR(m);
  #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);  /* 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);
  }
  
  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;
          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;
          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);

Cache object: 0f97d3cc22e913e3eb42afb95bf4a153