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

     /*      $NetBSD: ip_mroute.c,v 1.165 2022/03/15 21:39:59 andvar Exp $   */
     
     /*
      * Copyright (c) 1992, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * Stephen Deering of Stanford University.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)ip_mroute.c 8.2 (Berkeley) 11/15/93
     */
    
    /*
     * Copyright (c) 1989 Stephen Deering
     *
     * This code is derived from software contributed to Berkeley by
     * Stephen Deering of Stanford University.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)ip_mroute.c 8.2 (Berkeley) 11/15/93
     */
    
    /*
     * 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 1994
     * Modified by Charles M. Hannum, NetBSD, May 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: 1.2
     * and PIM-SMv2 and PIM-DM support, advanced API support,
     * bandwidth metering and signaling
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: ip_mroute.c,v 1.165 2022/03/15 21:39:59 andvar Exp $");
    
    #ifdef _KERNEL_OPT
    #include "opt_inet.h"
   #include "opt_ipsec.h"
   #include "opt_pim.h"
   #endif
   
   #ifdef PIM
   #define _PIM_VT 1
   #endif
   
   #include <sys/param.h>
   #include <sys/systm.h>
   #include <sys/callout.h>
   #include <sys/mbuf.h>
   #include <sys/socket.h>
   #include <sys/socketvar.h>
   #include <sys/errno.h>
   #include <sys/time.h>
   #include <sys/kernel.h>
   #include <sys/kmem.h>
   #include <sys/ioctl.h>
   #include <sys/syslog.h>
   
   #include <net/if.h>
   #include <net/raw_cb.h>
   
   #include <netinet/in.h>
   #include <netinet/in_var.h>
   #include <netinet/in_systm.h>
   #include <netinet/in_offload.h>
   #include <netinet/ip.h>
   #include <netinet/ip_var.h>
   #include <netinet/in_pcb.h>
   #include <netinet/udp.h>
   #include <netinet/igmp.h>
   #include <netinet/igmp_var.h>
   #include <netinet/ip_mroute.h>
   #ifdef PIM
   #include <netinet/pim.h>
   #include <netinet/pim_var.h>
   #endif
   #include <netinet/ip_encap.h>
   
   #ifdef IPSEC
   #include <netipsec/ipsec.h>
   #include <netipsec/key.h>
   #endif
   
   #define IP_MULTICASTOPTS 0
   #define M_PULLUP(m, len)                                                 \
           do {                                                             \
                   if ((m) && ((m)->m_flags & M_EXT || (m)->m_len < (len))) \
                           (m) = m_pullup((m), (len));                      \
           } while (/*CONSTCOND*/ 0)
   
   /*
    * Globals.  All but ip_mrouter and ip_mrtproto could be static,
    * except for netstat or debugging purposes.
    */
   struct socket  *ip_mrouter  = NULL;
   int             ip_mrtproto = IGMP_DVMRP;    /* for netstat only */
   
   #define MFCHASH(a, g)                                                   \
           ((((a).s_addr >> 20) ^ ((a).s_addr >> 10) ^ (a).s_addr ^        \
             ((g).s_addr >> 20) ^ ((g).s_addr >> 10) ^ (g).s_addr) & mfchash)
   LIST_HEAD(mfchashhdr, mfc) *mfchashtbl;
   u_long  mfchash;
   
   u_char          nexpire[MFCTBLSIZ];
   struct vif      viftable[MAXVIFS];
   struct mrtstat  mrtstat;
   u_int           mrtdebug = 0;   /* debug level */
   #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)
   
   u_int tbfdebug = 0;     /* tbf debug level */
   
   /* vif attachment using sys/netinet/ip_encap.c */
   static void vif_input(struct mbuf *, int, int, void *);
   static int vif_encapcheck(struct mbuf *, int, int, void *);
   
   static const struct encapsw vif_encapsw = {
           .encapsw4 = {
                   .pr_input       = vif_input,
                   .pr_ctlinput    = NULL,
           }
   };
   
   #define         EXPIRE_TIMEOUT  (hz / 4)        /* 4x / second */
   #define         UPCALL_EXPIRE   6               /* number of timeouts */
   
   /*
    * Define the token bucket filter structures
    */
   
   #define         TBF_REPROCESS   (hz / 100)      /* 100x / second */
   
   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 set_assert(int);
   static int add_vif(struct vifctl *);
   static int del_vif(vifi_t *);
   static void update_mfc_params(struct mfc *, struct mfcctl2 *);
   static void init_mfc_params(struct mfc *, struct mfcctl2 *);
   static void expire_mfc(struct mfc *);
   static int add_mfc(struct sockopt *);
   #ifdef UPCALL_TIMING
   static void collate(struct timeval *);
   #endif
   static int del_mfc(struct sockopt *);
   static int set_api_config(struct sockopt *); /* chose API capabilities */
   static int socket_send(struct socket *, struct mbuf *, struct sockaddr_in *);
   static void expire_upcalls(void *);
   static int ip_mdq(struct mbuf *, struct ifnet *, struct mfc *);
   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_int32_t);
   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 *);
   static int ip_mforward_real(struct mbuf *, struct ifnet *);
   
   
   /*
    * Bandwidth monitoring
    */
   static void free_bw_list(struct bw_meter *);
   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 *, int , struct timeval *);
   static void bw_meter_prepare_upcall(struct bw_meter *, struct timeval *);
   static void bw_upcalls_send(void);
   static void schedule_bw_meter(struct bw_meter *, struct timeval *);
   static void unschedule_bw_meter(struct bw_meter *);
   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
   
   #define ENCAP_TTL       64
   #define ENCAP_PROTO     IPPROTO_IPIP
   
   /* prototype IP hdr for encapsulated packets */
   static const struct ip multicast_encap_iphdr = {
           .ip_hl = sizeof(struct ip) >> 2,
           .ip_v = IPVERSION,
           .ip_len = sizeof(struct ip),
           .ip_ttl = ENCAP_TTL,
           .ip_p = ENCAP_PROTO,
   };
   
   /*
    * Bandwidth meter variables and constants
    */
   
   /*
    * 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];
   struct callout 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 */
   struct callout  bw_upcalls_ch;
   #define BW_UPCALLS_PERIOD (hz)          /* periodical flush of bw upcalls */
   
   #ifdef PIM
   struct pimstat pimstat;
   
   /*
    * 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 = {
           .ip_v = IPVERSION,
           .ip_hl = sizeof(struct ip) >> 2,
           .ip_len = sizeof(struct ip),
           .ip_ttl = ENCAP_TTL,
           .ip_p = IPPROTO_PIM,
   };
   
   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 = 0;
   
   static struct callout expire_upcalls_ch;
   
   /*
    * 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 u_int32_t mrt_api_support = (MRT_MFC_FLAGS_DISABLE_WRONGVIF |
                                             MRT_MFC_FLAGS_BORDER_VIF |
                                             MRT_MFC_RP |
                                             MRT_MFC_BW_UPCALL);
   static u_int32_t mrt_api_config = 0;
   
   /*
    * 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(struct in_addr *o, struct in_addr *g)
   {
           struct mfc *rt;
   
           LIST_FOREACH(rt, &mfchashtbl[MFCHASH(*o, *g)], mfc_hash) {
                   if (in_hosteq(rt->mfc_origin, *o) &&
                       in_hosteq(rt->mfc_mcastgrp, *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) do {                                      \
           int xxs;                                                        \
           delta = (a).tv_usec - (b).tv_usec;                              \
           xxs = (a).tv_sec - (b).tv_sec;                                  \
           switch (xxs) {                                                  \
           case 2:                                                         \
                   delta += 1000000;                                       \
                   /* fall through */                                      \
           case 1:                                                         \
                   delta += 1000000;                                       \
                   /* fall through */                                      \
           case 0:                                                         \
                   break;                                                  \
           default:                                                        \
                   delta += (1000000 * xxs);                               \
                   break;                                                  \
           }                                                               \
   } while (/*CONSTCOND*/ 0)
   
   #ifdef UPCALL_TIMING
   u_int32_t upcall_data[51];
   #endif /* UPCALL_TIMING */
   
   /*
    * Handle MRT setsockopt commands to modify the multicast routing tables.
    */
   int
   ip_mrouter_set(struct socket *so, struct sockopt *sopt)
   {
           int error;
           int optval;
           struct vifctl vifc;
           vifi_t vifi;
           struct bw_upcall bwuc;
   
           if (sopt->sopt_name != MRT_INIT && so != ip_mrouter)
                   error = ENOPROTOOPT;
           else {
                   switch (sopt->sopt_name) {
                   case MRT_INIT:
                           error = sockopt_getint(sopt, &optval);
                           if (error)
                                   break;
   
                           error = ip_mrouter_init(so, optval);
                           break;
                   case MRT_DONE:
                           error = ip_mrouter_done();
                           break;
                   case MRT_ADD_VIF:
                           error = sockopt_get(sopt, &vifc, sizeof(vifc));
                           if (error)
                                   break;
                           error = add_vif(&vifc);
                           break;
                   case MRT_DEL_VIF:
                           error = sockopt_get(sopt, &vifi, sizeof(vifi));
                           if (error)
                                   break;
                           error = del_vif(&vifi);
                           break;
                   case MRT_ADD_MFC:
                           error = add_mfc(sopt);
                           break;
                   case MRT_DEL_MFC:
                           error = del_mfc(sopt);
                           break;
                   case MRT_ASSERT:
                           error = sockopt_getint(sopt, &optval);
                           if (error)
                                   break;
                           error = set_assert(optval);
                           break;
                   case MRT_API_CONFIG:
                           error = set_api_config(sopt);
                           break;
                   case MRT_ADD_BW_UPCALL:
                           error = sockopt_get(sopt, &bwuc, sizeof(bwuc));
                           if (error)
                                   break;
                           error = add_bw_upcall(&bwuc);
                           break;
                   case MRT_DEL_BW_UPCALL:
                           error = sockopt_get(sopt, &bwuc, sizeof(bwuc));
                           if (error)
                                   break;
                           error = del_bw_upcall(&bwuc);
                           break;
                   default:
                           error = ENOPROTOOPT;
                           break;
                   }
           }
           return error;
   }
   
   /*
    * Handle MRT getsockopt commands
    */
   int
   ip_mrouter_get(struct socket *so, struct sockopt *sopt)
   {
           int error;
   
           if (so != ip_mrouter)
                   error = ENOPROTOOPT;
           else {
                   switch (sopt->sopt_name) {
                   case MRT_VERSION:
                           error = sockopt_setint(sopt, 0x0305); /* XXX !!!! */
                           break;
                   case MRT_ASSERT:
                           error = sockopt_setint(sopt, pim_assert);
                           break;
                   case MRT_API_SUPPORT:
                           error = sockopt_set(sopt, &mrt_api_support,
                               sizeof(mrt_api_support));
                           break;
                   case MRT_API_CONFIG:
                           error = sockopt_set(sopt, &mrt_api_config,
                               sizeof(mrt_api_config));
                           break;
                   default:
                           error = ENOPROTOOPT;
                           break;
                   }
           }
           return error;
   }
   
   /*
    * Handle ioctl commands to obtain information from the cache
    */
   int
   mrt_ioctl(struct socket *so, u_long cmd, void *data)
   {
           int error;
   
           if (so != ip_mrouter)
                   error = EINVAL;
           else
                   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 = splsoftnet();
           rt = mfc_find(&req->src, &req->grp);
           if (rt == NULL) {
                   splx(s);
                   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;
           splx(s);
   
           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 v)
   {
           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 (v != 1)
                   return EINVAL;
   
           if (ip_mrouter != NULL)
                   return EADDRINUSE;
   
           ip_mrouter = so;
   
           mfchashtbl = hashinit(MFCTBLSIZ, HASH_LIST, true, &mfchash);
           memset((void *)nexpire, 0, sizeof(nexpire));
   
           pim_assert = 0;
   
           callout_init(&expire_upcalls_ch, 0);
           callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
                         expire_upcalls, NULL);
   
           callout_init(&bw_upcalls_ch, 0);
           callout_reset(&bw_upcalls_ch, BW_UPCALLS_PERIOD,
                         expire_bw_upcalls_send, NULL);
   
           callout_init(&bw_meter_ch, 0);
           callout_reset(&bw_meter_ch, BW_METER_PERIOD,
                         expire_bw_meter_process, NULL);
   
           if (mrtdebug)
                   log(LOG_DEBUG, "ip_mrouter_init\n");
   
           return 0;
   }
   
   /*
    * Disable multicast routing
    */
   int
   ip_mrouter_done(void)
   {
           vifi_t vifi;
           struct vif *vifp;
           int i;
           int s;
   
           s = splsoftnet();
   
           /* Clear out all the vifs currently in use. */
           for (vifi = 0; vifi < numvifs; vifi++) {
                   vifp = &viftable[vifi];
                   if (!in_nullhost(vifp->v_lcl_addr))
                           reset_vif(vifp);
           }
   
           numvifs = 0;
           pim_assert = 0;
           mrt_api_config = 0;
   
           callout_stop(&expire_upcalls_ch);
           callout_stop(&bw_upcalls_ch);
           callout_stop(&bw_meter_ch);
   
           /*
            * Free all multicast forwarding cache entries.
            */
           for (i = 0; i < MFCTBLSIZ; i++) {
                   struct mfc *rt, *nrt;
   
                   for (rt = LIST_FIRST(&mfchashtbl[i]); rt; rt = nrt) {
                           nrt = LIST_NEXT(rt, mfc_hash);
   
                           expire_mfc(rt);
                   }
           }
   
           memset((void *)nexpire, 0, sizeof(nexpire));
           hashdone(mfchashtbl, HASH_LIST, mfchash);
           mfchashtbl = NULL;
   
           bw_upcalls_n = 0;
           memset(bw_meter_timers, 0, sizeof(bw_meter_timers));
   
           /* Reset de-encapsulation cache. */
   
           ip_mrouter = NULL;
   
           splx(s);
   
           if (mrtdebug)
                   log(LOG_DEBUG, "ip_mrouter_done\n");
   
           return 0;
   }
   
   void
   ip_mrouter_detach(struct ifnet *ifp)
   {
           int vifi, i;
           struct vif *vifp;
           struct mfc *rt;
           struct rtdetq *rte;
   
           /* XXX not sure about side effect to userland routing daemon */
           for (vifi = 0; vifi < numvifs; vifi++) {
                   vifp = &viftable[vifi];
                   if (vifp->v_ifp == ifp)
                           reset_vif(vifp);
           }
           for (i = 0; i < MFCTBLSIZ; i++) {
                   if (nexpire[i] == 0)
                           continue;
                   LIST_FOREACH(rt, &mfchashtbl[i], mfc_hash) {
                           for (rte = rt->mfc_stall; rte; rte = rte->next) {
                                   if (rte->ifp == ifp)
                                           rte->ifp = NULL;
                           }
                   }
           }
   }
   
   /*
    * Set PIM assert processing global
    */
   static int
   set_assert(int i)
   {
           pim_assert = !!i;
           return 0;
   }
   
   /*
    * Configure API capabilities
    */
   static int
   set_api_config(struct sockopt *sopt)
   {
           u_int32_t apival;
           int i, error;
   
           /*
            * 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
            */
           error = sockopt_get(sopt, &apival, sizeof(apival));
           if (error)
                   return error;
           if (numvifs > 0)
                   return EPERM;
           if (pim_assert)
                   return EPERM;
           for (i = 0; i < MFCTBLSIZ; i++) {
                   if (LIST_FIRST(&mfchashtbl[i]) != NULL)
                           return EPERM;
           }
   
           mrt_api_config = apival & mrt_api_support;
           return 0;
   }
   
   /*
    * Add a vif to the vif table
    */
   static int
   add_vif(struct vifctl *vifcp)
   {
           struct vif *vifp;
           struct ifnet *ifp;
           int error, s;
           struct sockaddr_in sin;
   
           if (vifcp->vifc_vifi >= MAXVIFS)
                   return EINVAL;
           if (in_nullhost(vifcp->vifc_lcl_addr))
                   return EADDRNOTAVAIL;
   
           vifp = &viftable[vifcp->vifc_vifi];
           if (!in_nullhost(vifp->v_lcl_addr))
                   return EADDRINUSE;
   
           /* 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
           {
                   struct ifaddr *ifa;
   
                   sockaddr_in_init(&sin, &vifcp->vifc_lcl_addr, 0);
                   s = pserialize_read_enter();
                   ifa = ifa_ifwithaddr(sintosa(&sin));
                   if (ifa == NULL) {
                           pserialize_read_exit(s);
                           return EADDRNOTAVAIL;
                   }
                   ifp = ifa->ifa_ifp;
                   /* FIXME NOMPSAFE */
                   pserialize_read_exit(s);
           }
   
           if (vifcp->vifc_flags & VIFF_TUNNEL) {
                   if (vifcp->vifc_flags & VIFF_SRCRT) {
                           log(LOG_ERR, "source routed tunnels not supported\n");
                           return EOPNOTSUPP;
                   }
   
                   /* attach this vif to decapsulator dispatch table */
                   /*
                    * XXX Use addresses in registration so that matching
                    * can be done with radix tree in decapsulator.  But,
                    * we need to check inner header for multicast, so
                    * this requires both radix tree lookup and then a
                    * function to check, and this is not supported yet.
                    */
                   error = encap_lock_enter();
                   if (error)
                           return error;
                   vifp->v_encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV4,
                       vif_encapcheck, &vif_encapsw, vifp);
                   encap_lock_exit();
                   if (!vifp->v_encap_cookie)
                           return EINVAL;
   
                   /* Create a fake encapsulation interface. */
                   ifp = malloc(sizeof(*ifp), M_MRTABLE, M_WAITOK|M_ZERO);
                   snprintf(ifp->if_xname, sizeof(ifp->if_xname),
                            "mdecap%d", vifcp->vifc_vifi);
   
                   /* Prepare cached route entry. */
                   memset(&vifp->v_route, 0, sizeof(vifp->v_route));
   #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 *)ifp);
                   if (reg_vif_num == VIFI_INVALID) {
                           memset(ifp, 0, sizeof(*ifp));
                           snprintf(ifp->if_xname, sizeof(ifp->if_xname),
                                    "register_vif");
                           ifp->if_flags = IFF_LOOPBACK;
                           memset(&vifp->v_route, 0, 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. */
                   sockaddr_in_init(&sin, &zeroin_addr, 0);
                   error = if_mcast_op(ifp, SIOCADDMULTI, sintosa(&sin));
                   if (error)
                           return error;
           }
   
           s = splsoftnet();
   
           /* Define parameters for the tbf structure. */
           vifp->tbf_q = NULL;
           vifp->tbf_t = &vifp->tbf_q;
           microtime(&vifp->tbf_last_pkt_t);
           vifp->tbf_n_tok = 0;
           vifp->tbf_q_len = 0;
           vifp->tbf_max_q_len = MAXQSIZE;
   
           vifp->v_flags = vifcp->vifc_flags;
           vifp->v_threshold = vifcp->vifc_threshold;
           /* scaling up here allows division by 1024 in critical code */
           vifp->v_rate_limit = vifcp->vifc_rate_limit * 1024 / 1000;
           vifp->v_lcl_addr = vifcp->vifc_lcl_addr;
           vifp->v_rmt_addr = vifcp->vifc_rmt_addr;
           vifp->v_ifp = ifp;
           /* 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;
   
           callout_init(&vifp->v_repq_ch, 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 %x, %s %x, thresh %x, rate %d\n",
                       vifcp->vifc_vifi,
                       ntohl(vifcp->vifc_lcl_addr.s_addr),
                       (vifcp->vifc_flags & VIFF_TUNNEL) ? "rmtaddr" : "mask",
                       ntohl(vifcp->vifc_rmt_addr.s_addr),
                       vifcp->vifc_threshold,
                       vifcp->vifc_rate_limit);
   
           return 0;
   }
   
   void
   reset_vif(struct vif *vifp)
   {
           struct mbuf *m, *n;
           struct ifnet *ifp;
           struct sockaddr_in sin;
   
           callout_stop(&vifp->v_repq_ch);
   
           /* detach this vif from decapsulator dispatch table */
           encap_lock_enter();
           encap_detach(vifp->v_encap_cookie);
           encap_lock_exit();
           vifp->v_encap_cookie = NULL;
   
           /*
            * Free packets queued at the interface
            */
           for (m = vifp->tbf_q; m != NULL; m = n) {
                   n = m->m_nextpkt;
                   m_freem(m);
           }
   
           if (vifp->v_flags & VIFF_TUNNEL)
                   free(vifp->v_ifp, M_MRTABLE);
           else if (vifp->v_flags & VIFF_REGISTER) {
   #ifdef PIM
                   reg_vif_num = VIFI_INVALID;
   #endif
           } else {
                   sockaddr_in_init(&sin, &zeroin_addr, 0);
                   ifp = vifp->v_ifp;
                   if_mcast_op(ifp, SIOCDELMULTI, sintosa(&sin));
           }
           memset((void *)vifp, 0, sizeof(*vifp));
   }
   
   /*
    * Delete a vif from the vif table
    */
   static int
   del_vif(vifi_t *vifip)
   {
           struct vif *vifp;
           vifi_t vifi;
           int s;
   
           if (*vifip >= numvifs)
                   return EINVAL;
   
           vifp = &viftable[*vifip];
           if (in_nullhost(vifp->v_lcl_addr))
                   return EADDRNOTAVAIL;
   
           s = splsoftnet();
   
           reset_vif(vifp);
   
           /* Adjust numvifs down */
           for (vifi = numvifs; vifi > 0; vifi--)
                   if (!in_nullhost(viftable[vifi - 1].v_lcl_addr))
                           break;
           numvifs = vifi;
   
           splx(s);
   
           if (mrtdebug)
                   log(LOG_DEBUG, "del_vif %d, numvifs %d\n", *vifip, numvifs);
   
           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 = zeroin_addr;
   }
   
   /*
    * 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;
          timerclear(&rt->mfc_last_assert);
  }
  
  static void
  expire_mfc(struct mfc *rt)
  {
          struct rtdetq *rte, *nrte;
  
          free_bw_list(rt->mfc_bw_meter);
  
          for (rte = rt->mfc_stall; rte != NULL; rte = nrte) {
                  nrte = rte->next;
                  m_freem(rte->m);
                  free(rte, M_MRTABLE);
          }
  
          LIST_REMOVE(rt, mfc_hash);
          free(rt, M_MRTABLE);
  }
  
  /*
   * Add an mfc entry
   */
  static int
  add_mfc(struct sockopt *sopt)
  {
          struct mfcctl2 mfcctl2;
          struct mfcctl2 *mfccp;
          struct mfc *rt;
          u_int32_t hash = 0;
          struct rtdetq *rte, *nrte;
          u_short nstl;
          int s;
          int error;
  
          /*
           * select data size depending on API version.
           */
          mfccp = &mfcctl2;
          memset(&mfcctl2, 0, sizeof(mfcctl2));
  
          if (mrt_api_config & MRT_API_FLAGS_ALL)
                  error = sockopt_get(sopt, mfccp, sizeof(struct mfcctl2));
          else
                  error = sockopt_get(sopt, mfccp, sizeof(struct mfcctl));
  
          if (error)
                  return error;
  
          s = splsoftnet();
          rt = mfc_find(&mfccp->mfcc_origin, &mfccp->mfcc_mcastgrp);
  
          /* If an entry already exists, just update the fields */
          if (rt) {
                  if (mrtdebug & DEBUG_MFC)
                          log(LOG_DEBUG, "add_mfc update o %x g %x p %x\n",
                              ntohl(mfccp->mfcc_origin.s_addr),
                              ntohl(mfccp->mfcc_mcastgrp.s_addr),
                              mfccp->mfcc_parent);
  
                  update_mfc_params(rt, mfccp);
  
                  splx(s);
                  return 0;
          }
  
          /*
           * Find the entry for which the upcall was made and update
           */
          nstl = 0;
          hash = MFCHASH(mfccp->mfcc_origin, mfccp->mfcc_mcastgrp);
          LIST_FOREACH(rt, &mfchashtbl[hash], mfc_hash) {
                  if (in_hosteq(rt->mfc_origin, mfccp->mfcc_origin) &&
                      in_hosteq(rt->mfc_mcastgrp, mfccp->mfcc_mcastgrp) &&
                      rt->mfc_stall != NULL) {
                          if (nstl++)
                                  log(LOG_ERR, "add_mfc %s o %x g %x p %x dbx %p\n",
                                      "multiple kernel entries",
                                      ntohl(mfccp->mfcc_origin.s_addr),
                                      ntohl(mfccp->mfcc_mcastgrp.s_addr),
                                      mfccp->mfcc_parent, rt->mfc_stall);
  
                          if (mrtdebug & DEBUG_MFC)
                                  log(LOG_DEBUG, "add_mfc o %x g %x p %x dbg %p\n",
                                      ntohl(mfccp->mfcc_origin.s_addr),
                                      ntohl(mfccp->mfcc_mcastgrp.s_addr),
                                      mfccp->mfcc_parent, rt->mfc_stall);
  
                          rte = rt->mfc_stall;
                          init_mfc_params(rt, mfccp);
                          rt->mfc_stall = NULL;
  
                          rt->mfc_expire = 0; /* Don't clean this guy up */
                          nexpire[hash]--;
  
                          /* free packets Qed at the end of this entry */
                          for (; rte != NULL; rte = nrte) {
                                  nrte = rte->next;
                                  if (rte->ifp) {
                                          ip_mdq(rte->m, rte->ifp, rt);
                                  }
                                  m_freem(rte->m);
  #ifdef UPCALL_TIMING
                                  collate(&rte->t);
  #endif /* UPCALL_TIMING */
                                  free(rte, M_MRTABLE);
                          }
                  }
          }
  
          /*
           * It is possible that an entry is being inserted without an upcall
           */
          if (nstl == 0) {
                  /*
                   * No mfc; make a new one
                   */
                  if (mrtdebug & DEBUG_MFC)
                          log(LOG_DEBUG, "add_mfc no upcall o %x g %x p %x\n",
                              ntohl(mfccp->mfcc_origin.s_addr),
                              ntohl(mfccp->mfcc_mcastgrp.s_addr),
                              mfccp->mfcc_parent);
  
                  LIST_FOREACH(rt, &mfchashtbl[hash], mfc_hash) {
                          if (in_hosteq(rt->mfc_origin, mfccp->mfcc_origin) &&
                              in_hosteq(rt->mfc_mcastgrp, mfccp->mfcc_mcastgrp)) {
                                  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 = 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 */
                          LIST_INSERT_HEAD(&mfchashtbl[hash], rt, mfc_hash);
                  }
          }
  
          splx(s);
          return 0;
  }
  
  #ifdef UPCALL_TIMING
  /*
   * collect delay statistics on the upcalls
   */
  static void
  collate(struct timeval *t)
  {
          u_int32_t d;
          struct timeval tp;
          u_int32_t delta;
  
          microtime(&tp);
  
          if (timercmp(t, &tp, <)) {
                  TV_DELTA(tp, *t, delta);
  
                  d = delta >> 10;
                  if (d > 50)
                          d = 50;
  
                  ++upcall_data[d];
          }
  }
  #endif /* UPCALL_TIMING */
  
  /*
   * Delete an mfc entry
   */
  static int
  del_mfc(struct sockopt *sopt)
  {
          struct mfcctl2 mfcctl2;
          struct mfcctl2 *mfccp;
          struct mfc *rt;
          int s;
          int error;
  
          /*
           * XXX: for deleting MFC entries the information in entries
           * of size "struct mfcctl" is sufficient.
           */
  
          mfccp = &mfcctl2;
          memset(&mfcctl2, 0, sizeof(mfcctl2));
  
          error = sockopt_get(sopt, mfccp, sizeof(struct mfcctl));
          if (error) {
                  /* Try with the size of mfcctl2. */
                  error = sockopt_get(sopt, mfccp, sizeof(struct mfcctl2));
                  if (error)
                          return error;
          }
  
          if (mrtdebug & DEBUG_MFC)
                  log(LOG_DEBUG, "del_mfc origin %x mcastgrp %x\n",
                      ntohl(mfccp->mfcc_origin.s_addr),
                      ntohl(mfccp->mfcc_mcastgrp.s_addr));
  
          s = splsoftnet();
  
          rt = mfc_find(&mfccp->mfcc_origin, &mfccp->mfcc_mcastgrp);
          if (rt == NULL) {
                  splx(s);
                  return EADDRNOTAVAIL;
          }
  
          /*
           * free the bw_meter entries
           */
          free_bw_list(rt->mfc_bw_meter);
          rt->mfc_bw_meter = NULL;
  
          LIST_REMOVE(rt, mfc_hash);
          free(rt, M_MRTABLE);
  
          splx(s);
          return 0;
  }
  
  static int
  socket_send(struct socket *s, struct mbuf *mm, struct sockaddr_in *src)
  {
          if (s) {
                  if (sbappendaddr(&s->so_rcv, sintosa(src), mm, NULL) != 0) {
                          sorwakeup(s);
                          return 0;
                  }
                  soroverflow(s);
          }
          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 IP_HDR_LEN  20  /* # bytes of fixed IP header (excluding options) */
  #define TUNNEL_LEN  12  /* # bytes of IP option for tunnel encapsulation  */
  
  int
  ip_mforward(struct mbuf *m, struct ifnet *ifp)
  {
          int rc;
          /*
           * save csum_flags to uphold the 
           * "unscathed" guarantee.
           * ip_output() relies on that and
           * without it we send out
           * multicast packets with an invalid
           * checksum
           *
           * see PR kern/55779
           */
          int csum_flags = m->m_pkthdr.csum_flags;
  
          /*
           * Temporarily clear any in-bound checksum flags for this packet.
           */
          m->m_pkthdr.csum_flags = 0;
  
          rc = ip_mforward_real(m, ifp);
  
          m->m_pkthdr.csum_flags = csum_flags;
  
          return rc;
  }
  
  static int
  ip_mforward_real(struct mbuf *m, struct ifnet *ifp)
  {
          struct ip *ip = mtod(m, struct ip *);
          struct mfc *rt;
          static int srctun = 0;
          struct mbuf *mm;
          struct sockaddr_in sin;
          int s;
          vifi_t vifi;
  
          if (mrtdebug & DEBUG_FORWARD)
                  log(LOG_DEBUG, "ip_mforward: src %x, dst %x, ifp %p\n",
                      ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), ifp);
  
          /*
           * XXX XXX: Why do we check [1] against IPOPT_LSRR? Because we
           * expect [0] to be IPOPT_NOP, maybe? In all cases that doesn't
           * make a lot of sense, a forged packet can just put two IPOPT_NOPs
           * followed by one IPOPT_LSRR, and bypass the check.
           */
          if (ip->ip_hl < (IP_HDR_LEN + 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.
                   */
                  if ((srctun++ % 1000) == 0)
                          log(LOG_ERR,
                              "ip_mforward: received source-routed packet from %x\n",
                              ntohl(ip->ip_src.s_addr));
                  return EOPNOTSUPP;
          }
  
          /*
           * 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 || IN_LOCAL_GROUP(ip->ip_dst.s_addr))
                  return 0;
  
          /*
           * Determine forwarding vifs from the forwarding cache table
           */
          s = splsoftnet();
          ++mrtstat.mrts_mfc_lookups;
          rt = mfc_find(&ip->ip_src, &ip->ip_dst);
  
          /* Entry exists, so forward if necessary */
          if (rt != NULL) {
                  splx(s);
                  return ip_mdq(m, ifp, rt);
          } else {
                  /*
                   * If we don't have a route for packet's origin, make a copy
                   * of the packet and send message to routing daemon.
                   */
  
                  struct mbuf *mb0;
                  struct rtdetq *rte;
                  u_int32_t hash;
                  const int hlen = ip->ip_hl << 2;
  #ifdef UPCALL_TIMING
                  struct timeval tp;
                  microtime(&tp);
  #endif
  
                  ++mrtstat.mrts_mfc_misses;
  
                  mrtstat.mrts_no_route++;
                  if (mrtdebug & (DEBUG_FORWARD | DEBUG_MFC))
                          log(LOG_DEBUG, "ip_mforward: no rte s %x g %x\n",
                              ntohl(ip->ip_src.s_addr),
                              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 = malloc(sizeof(*rte), M_MRTABLE, M_NOWAIT);
                  if (rte == NULL) {
                          splx(s);
                          return ENOBUFS;
                  }
                  mb0 = m_copypacket(m, M_DONTWAIT);
                  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, ip->ip_dst);
                  LIST_FOREACH(rt, &mfchashtbl[hash], mfc_hash) {
                          if (in_hosteq(ip->ip_src, rt->mfc_origin) &&
                              in_hosteq(ip->ip_dst, rt->mfc_mcastgrp) &&
                              rt->mfc_stall != NULL)
                                  break;
                  }
  
                  if (rt == NULL) {
                          int i;
                          struct igmpmsg *im;
  
                          /*
                           * 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 = 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_copym(m, 0, hlen, M_DONTWAIT);
                          M_PULLUP(mm, 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++;
  
                          sockaddr_in_init(&sin, &ip->ip_src, 0);
                          if (socket_send(ip_mrouter, mm, &sin) < 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 = ip->ip_src;
                          rt->mfc_mcastgrp = ip->ip_dst;
                          rt->mfc_pkt_cnt = 0;
                          rt->mfc_byte_cnt = 0;
                          rt->mfc_wrong_if = 0;
                          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;
  
                          /* clear the RP address */
                          rt->mfc_rp = zeroin_addr;
  
                          rt->mfc_bw_meter = NULL;
  
                          /* link into table */
                          LIST_INSERT_HEAD(&mfchashtbl[hash], rt, mfc_hash);
                          /* Add this entry to the end of the queue */
                          rt->mfc_stall = rte;
                  } else {
                          /* determine if q has overflowed */
                          struct rtdetq **p;
                          int npkts = 0;
  
                          /*
                           * 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)
                                  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->next = NULL;
                  rte->m = mb0;
                  rte->ifp = ifp;
  #ifdef UPCALL_TIMING
                  rte->t = tp;
  #endif
  
                  splx(s);
  
                  return 0;
          }
  }
  
  /*ARGSUSED*/
  static void
  expire_upcalls(void *v)
  {
          int i;
  
          /* XXX NOMPSAFE still need softnet_lock */
          mutex_enter(softnet_lock);
          KERNEL_LOCK(1, NULL);
  
          for (i = 0; i < MFCTBLSIZ; i++) {
                  struct mfc *rt, *nrt;
  
                  if (nexpire[i] == 0)
                          continue;
  
                  for (rt = LIST_FIRST(&mfchashtbl[i]); rt; rt = nrt) {
                          nrt = LIST_NEXT(rt, mfc_hash);
  
                          if (rt->mfc_expire == 0 || --rt->mfc_expire > 0)
                                  continue;
                          nexpire[i]--;
  
                          /*
                           * free the bw_meter entries
                           */
                          while (rt->mfc_bw_meter != NULL) {
                                  struct bw_meter *x = rt->mfc_bw_meter;
  
                                  rt->mfc_bw_meter = x->bm_mfc_next;
                                  kmem_intr_free(x, sizeof(*x));
                          }
  
                          ++mrtstat.mrts_cache_cleanups;
                          if (mrtdebug & DEBUG_EXPIRE)
                                  log(LOG_DEBUG,
                                      "expire_upcalls: expiring (%x %x)\n",
                                      ntohl(rt->mfc_origin.s_addr),
                                      ntohl(rt->mfc_mcastgrp.s_addr));
  
                          expire_mfc(rt);
                  }
          }
  
          callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
              expire_upcalls, NULL);
  
          KERNEL_UNLOCK_ONE(NULL);
          mutex_exit(softnet_lock);
  }
  
  /*
   * Macro to send packet on vif.
   */
  #define MC_SEND(ip, vifp, m) do {                                       \
          if ((vifp)->v_flags & VIFF_TUNNEL)                              \
                  encap_send((ip), (vifp), (m));                          \
          else                                                            \
                  phyint_send((ip), (vifp), (m));                         \
  } while (/*CONSTCOND*/ 0)
  
  /*
   * Packet forwarding routine once entry in the cache is made
   */
  static int
  ip_mdq(struct mbuf *m, struct ifnet *ifp, struct mfc *rt)
  {
          struct ip *ip = mtod(m, struct ip *);
          vifi_t vifi;
          struct vif *vifp;
          struct sockaddr_in sin;
          const int plen = ntohs(ip->ip_len) - (ip->ip_hl << 2);
  
          /*
           * 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",
                              ifp, vifi,
                              vifi >= numvifs ? 0 : 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_int32_t 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) {
                                  /* The iif is not found: ignore the packet. */
                                  return 0;
                          }
  
                          if (rt->mfc_flags[vifi] &
                              MRT_MFC_FLAGS_DISABLE_WRONGVIF) {
                                  /* WRONGVIF disabled: ignore the packet */
                                  return 0;
                          }
  
                          microtime(&now);
  
                          TV_DELTA(rt->mfc_last_assert, now, delta);
  
                          if (delta > ASSERT_MSG_TIME) {
                                  struct igmpmsg *im;
                                  const int hlen = ip->ip_hl << 2;
                                  struct mbuf *mm =
                                      m_copym(m, 0, hlen, M_DONTWAIT);
  
                                  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++;
  
                                  sockaddr_in_init(&sin, &im->im_src, 0);
                                  if (socket_send(ip_mrouter, mm, &sin) < 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 (in_hosteq(ip->ip_src, viftable[vifi].v_lcl_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 (vifp = viftable, vifi = 0; vifi < numvifs; vifp++, vifi++) {
                  if ((rt->mfc_ttls[vifi] > 0) &&
                          (ip->ip_ttl > rt->mfc_ttls[vifi])) {
                          vifp->v_pkt_out++;
                          vifp->v_bytes_out += plen;
  #ifdef PIM
                          if (vifp->v_flags & VIFF_REGISTER)
                                  pim_register_send(ip, vifp, m, rt);
                          else
  #endif
                          MC_SEND(ip, vifp, m);
                  }
          }
  
          /*
           * Perform upcall-related bw measuring.
           */
          if (rt->mfc_bw_meter != NULL) {
                  struct bw_meter *x;
                  struct timeval now;
  
                  microtime(&now);
                  for (x = rt->mfc_bw_meter; x != NULL; x = x->bm_mfc_next)
                          bw_meter_receive_packet(x, plen, &now);
          }
  
          return 0;
  }
  
  static void
  phyint_send(struct ip *ip, struct vif *vifp, struct mbuf *m)
  {
          struct mbuf *mb_copy;
          const 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);
          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 *),
                      ntohs(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 = ntohs(ip->ip_len) + sizeof(multicast_encap_iphdr);
  
          /* Take care of delayed checksums */
          if (m->m_pkthdr.csum_flags & (M_CSUM_TCPv4|M_CSUM_UDPv4)) {
                  in_undefer_cksum_tcpudp(m);
                  m->m_pkthdr.csum_flags &= ~(M_CSUM_TCPv4|M_CSUM_UDPv4);
          }
  
          /*
           * 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_DATA);
          if (mb_copy == NULL)
                  return;
          mb_copy->m_data += max_linkhdr;
          mb_copy->m_pkthdr.len = len;
          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 - max_linkhdr;
          if (i > len)
                  i = len;
          mb_copy = m_pullup(mb_copy, i);
          if (mb_copy == NULL)
                  return;
  
          /*
           * fill in the encapsulating IP header.
           */
          ip_copy = mtod(mb_copy, struct ip *);
          *ip_copy = multicast_encap_iphdr;
          if (len < IP_MINFRAGSIZE)
                  ip_copy->ip_id = 0;
          else
                  ip_copy->ip_id = ip_newid(NULL);
          ip_copy->ip_len = htons(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 *)((char *)ip_copy + sizeof(multicast_encap_iphdr));
          --ip->ip_ttl;
          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, ntohs(ip_copy->ip_len));
  }
  
  /*
   * De-encapsulate a packet and feed it back through ip input.
   */
  static void
  vif_input(struct mbuf *m, int off, int proto, void *eparg)
  {
          struct vif *vifp = eparg;
  
          KASSERT(vifp != NULL);
  
          if (proto != ENCAP_PROTO) {
                  m_freem(m);
                  mrtstat.mrts_bad_tunnel++;
                  return;
          }
  
          m_adj(m, off);
          m_set_rcvif(m, vifp->v_ifp);
  
          if (__predict_false(!pktq_enqueue(ip_pktq, m, 0))) {
                  m_freem(m);
          }
  }
  
  /*
   * Check if the packet should be received on the vif denoted by arg.
   * (The encap selection code will call this once per vif since each is
   * registered separately.)
   */
  static int
  vif_encapcheck(struct mbuf *m, int off, int proto, void *arg)
  {
          struct vif *vifp;
          struct ip ip;
  
  #ifdef DIAGNOSTIC
          if (!arg || proto != IPPROTO_IPV4)
                  panic("unexpected arg in vif_encapcheck");
  #endif
  
          /*
           * Accept the packet only if the inner header is multicast
           * and the outer header matches a tunnel-mode vif.  Order
           * checks in the hope that common non-matching packets will be
           * rejected quickly.  Assume that unicast IPv4 traffic in a
           * parallel tunnel (e.g. gif(4)) is unlikely.
           */
  
          /* Obtain the outer IP header and the vif pointer. */
          m_copydata(m, 0, sizeof(ip), (void *)&ip);
          vifp = (struct vif *)arg;
  
          /*
           * The outer source must match the vif's remote peer address.
           * For a multicast router with several tunnels, this is the
           * only check that will fail on packets in other tunnels,
           * assuming the local address is the same.
           */
          if (!in_hosteq(vifp->v_rmt_addr, ip.ip_src))
                  return 0;
  
          /* The outer destination must match the vif's local address. */
          if (!in_hosteq(vifp->v_lcl_addr, ip.ip_dst))
                  return 0;
  
          /* The vif must be of tunnel type. */
          if ((vifp->v_flags & VIFF_TUNNEL) == 0)
                  return 0;
  
          /* Check that the inner destination is multicast. */
          if (off + sizeof(ip) > m->m_pkthdr.len)
                  return 0;
          m_copydata(m, off, sizeof(ip), (void *)&ip);
          if (!IN_MULTICAST(ip.ip_dst.s_addr))
                  return 0;
  
          /*
           * We have checked that both the outer src and dst addresses
           * match the vif, and that the inner destination is multicast
           * (224/5).  By claiming more than 64, we intend to
           * preferentially take packets that also match a parallel
           * gif(4).
           */
          return 32 + 32 + 5;
  }
  
  /*
   * Token bucket filter module
   */
  static void
  tbf_control(struct vif *vifp, struct mbuf *m, struct ip *ip, u_int32_t len)
  {
  
          if (len > MAX_BKT_SIZE) {
                  /* drop if packet is too large */
                  mrtstat.mrts_pkt2large++;
                  m_freem(m);
                  return;
          }
  
          tbf_update_tokens(vifp);
  
          /*
           * If there are enough tokens, and the queue is empty, send this packet
           * out immediately.  Otherwise, try to insert it on this vif's queue.
           */
          if (vifp->tbf_q_len == 0) {
                  if (len <= vifp->tbf_n_tok) {
                          vifp->tbf_n_tok -= len;
                          tbf_send_packet(vifp, m);
                  } else {
                          /* queue packet and timeout till later */
                          tbf_queue(vifp, m);
                          callout_reset(&vifp->v_repq_ch, TBF_REPROCESS,
                              tbf_reprocess_q, vifp);
                  }
          } else {
                  if (vifp->tbf_q_len >= vifp->tbf_max_q_len &&
                      !tbf_dq_sel(vifp, ip)) {
                          /* queue full, and couldn't make room */
                          mrtstat.mrts_q_overflow++;
                          m_freem(m);
                  } else {
                          /* queue length low enough, or made room */
                          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 = splsoftnet();
  
          /* insert at tail */
          *vifp->tbf_t = m;
          vifp->tbf_t = &m->m_nextpkt;
          vifp->tbf_q_len++;
  
          splx(s);
  }
  
  /*
   * processes the queue at the interface
   */
  static void
  tbf_process_q(struct vif *vifp)
  {
          struct mbuf *m;
          int len;
          int s = splsoftnet();
  
          /*
           * Loop through the queue at the interface and send as many packets
           * as possible.
           */
          for (m = vifp->tbf_q; m != NULL; m = vifp->tbf_q) {
                  len = ntohs(mtod(m, struct ip *)->ip_len);
  
                  /* determine if the packet can be sent */
                  if (len <= vifp->tbf_n_tok) {
                          /* if so,
                           * reduce no of tokens, dequeue the packet,
                           * send the packet.
                           */
                          if ((vifp->tbf_q = m->m_nextpkt) == NULL)
                                  vifp->tbf_t = &vifp->tbf_q;
                          --vifp->tbf_q_len;
  
                          m->m_nextpkt = NULL;
                          vifp->tbf_n_tok -= len;
                          tbf_send_packet(vifp, m);
                  } else
                          break;
          }
          splx(s);
  }
  
  static void
  tbf_reprocess_q(void *arg)
  {
          struct vif *vifp = arg;
  
          if (ip_mrouter == NULL)
                  return;
  
          tbf_update_tokens(vifp);
          tbf_process_q(vifp);
  
          if (vifp->tbf_q_len != 0)
                  callout_reset(&vifp->v_repq_ch, TBF_REPROCESS,
                      tbf_reprocess_q, vifp);
  }
  
  /* 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)
  {
          u_int p;
          struct mbuf **mp, *m;
          int s = splsoftnet();
  
          p = priority(vifp, ip);
  
          for (mp = &vifp->tbf_q, m = *mp;
              m != NULL;
              mp = &m->m_nextpkt, m = *mp) {
                  if (p > priority(vifp, mtod(m, struct ip *))) {
                          if ((*mp = m->m_nextpkt) == NULL)
                                  vifp->tbf_t = mp;
                          --vifp->tbf_q_len;
  
                          m_freem(m);
                          mrtstat.mrts_drop_sel++;
                          splx(s);
                          return 1;
                  }
          }
          splx(s);
          return 0;
  }
  
  static void
  tbf_send_packet(struct vif *vifp, struct mbuf *m)
  {
          int error;
          int s = splsoftnet();
  
          if (vifp->v_flags & VIFF_TUNNEL) {
                  /* If tunnel options */
                  ip_output(m, NULL, &vifp->v_route, IP_FORWARDING, NULL, NULL);
          } else {
                  /* if physical interface option, extract the options and then send */
                  struct ip_moptions imo;
  
                  imo.imo_multicast_if_index = if_get_index(vifp->v_ifp);
                  imo.imo_multicast_ttl = mtod(m, struct ip *)->ip_ttl - 1;
                  imo.imo_multicast_loop = 1;
  
                  error = ip_output(m, NULL, NULL, IP_FORWARDING|IP_MULTICASTOPTS,
                      &imo, NULL);
  
                  if (mrtdebug & DEBUG_XMIT)
                          log(LOG_DEBUG, "phyint_send on vif %ld err %d\n",
                              (long)(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_int32_t tm;
          int s = splsoftnet();
  
          microtime(&tp);
  
          TV_DELTA(tp, vifp->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.
           */
          vifp->tbf_n_tok += tm * vifp->v_rate_limit / 8192;
          vifp->tbf_last_pkt_t = tp;
  
          if (vifp->tbf_n_tok > MAX_BKT_SIZE)
                  vifp->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 */
  
          /*
           * XXX XXX: We're reading the UDP header, but we didn't ensure
           * it was present in the packet.
           */
  
          /*
           * 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
           */
          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;
                  }
  
                  if (tbfdebug > 1)
                          log(LOG_DEBUG, "port %x prio %d\n",
                              ntohs(udp->uh_dport), prio);
          }
  
          return prio;
  }
  
  /*
   * Code for bandwidth monitors
   */
  
  /*
   * Define common interface for timeval-related methods
   */
  #define BW_TIMEVALCMP(tvp, uvp, cmp) timercmp((tvp), (uvp), cmp)
  #define BW_TIMEVALDECR(vvp, uvp) timersub((vvp), (uvp), (vvp))
  #define BW_TIMEVALADD(vvp, uvp) timeradd((vvp), (uvp), (vvp))
  
  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)
  {
          int s;
          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;
  
          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 = splsoftnet();
          mfc = mfc_find(&req->bu_src, &req->bu_dst);
          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 */
                  }
          }
  
          /* Allocate the new bw_meter entry */
          x = kmem_intr_alloc(sizeof(*x), KM_NOSLEEP);
          if (x == NULL) {
                  splx(s);
                  return ENOBUFS;
          }
  
          /* Set the new bw_meter entry */
          x->bm_threshold.b_time = req->bu_threshold.b_time;
          microtime(&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 */
          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);
                  kmem_intr_free(x, sizeof(*x));
          }
  }
  
  /*
   * Delete one or multiple bw_meter entries
   */
  static int
  del_bw_upcall(struct bw_upcall *req)
  {
          int s;
          struct mfc *mfc;
          struct bw_meter *x;
  
          if (!(mrt_api_config & MRT_MFC_BW_UPCALL))
                  return EOPNOTSUPP;
  
          s = splsoftnet();
          /* Find the corresponding MFC entry */
          mfc = mfc_find(&req->bu_src, &req->bu_dst);
          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;
                  free_bw_list(list);
                  splx(s);
                  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 */
  
                          unschedule_bw_meter(x);
                          splx(s);
                          /* Free the bw_meter entry */
                          kmem_intr_free(x, sizeof(*x));
                          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;
  
          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;
                  }
          }
  }
  
  /*
   * 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;
  
          /*
           * 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;
  }
  
  /*
   * 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 = {
                  .sin_len = sizeof(k_igmpsrc),
                  .sin_family = 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), (void *)&igmpmsg);
          m_copyback(m, sizeof(struct igmpmsg), len, (void *)&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 (/*CONSTCOND*/ 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;
  
          if (!(x->bm_flags & BW_METER_LEQ))
                  return;         /* XXX: we schedule timers only for "<=" entries */
  
          /*
           * 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;
  
          /*
           * 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(void)
  {
          int s;
          static uint32_t last_tv_sec;    /* last time we processed this */
  
          uint32_t loops;
          int i;
          struct timeval now, process_endtime;
  
          microtime(&now);
          if (last_tv_sec == now.tv_sec)
                  return;         /* nothing to do */
  
          loops = now.tv_sec - last_tv_sec;
          last_tv_sec = now.tv_sec;
          if (loops > BW_METER_BUCKETS)
                  loops = BW_METER_BUCKETS;
  
          s = splsoftnet();
          /*
           * 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);
                  }
          }
  
          /* Send all upcalls that are pending delivery */
          bw_upcalls_send();
  
          splx(s);
  }
  
  /*
   * A periodic function for sending all upcalls that are pending delivery
   */
  static void
  expire_bw_upcalls_send(void *unused)
  {
          int s;
  
          s = splsoftnet();
          bw_upcalls_send();
          splx(s);
  
          callout_reset(&bw_upcalls_ch, BW_UPCALLS_PERIOD,
              expire_bw_upcalls_send, NULL);
  }
  
  /*
   * 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();
  
          callout_reset(&bw_meter_ch, BW_METER_PERIOD,
              expire_bw_meter_process, NULL);
  }
  
  /*
   * 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: \n");
  
          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 = NULL;
                  mm = m_pullup(mm, sizeof(struct ip));
                  if (mm != NULL) {
                          ip = mtod(mm, struct ip *);
                          if ((mrt_api_config & MRT_MFC_RP) &&
                              !in_nullhost(rt->mfc_rp)) {
                                  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 & (M_CSUM_TCPv4|M_CSUM_UDPv4)) {
                  in_undefer_cksum_tcpudp(m);
                  m->m_pkthdr.csum_flags &= ~(M_CSUM_TCPv4|M_CSUM_UDPv4);
          }
  
          /*
           * 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 (ntohs(ip->ip_len) <= mtu) {
                  /* Turn the IP header into a valid one */
                  ip->ip_sum = 0;
                  ip->ip_sum = in_cksum(mb_copy, ip->ip_hl << 2);
          } else {
                  /* Fragment the packet */
                  if (ip_fragment(mb_copy, NULL, mtu) != 0) {
                          /* XXX: mb_copy was freed by ip_fragment() */
                          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 = {
                  .sin_len = sizeof(k_igmpsrc),
                  .sin_family = 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\n");
                  ++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) || in_nullhost(viftable[vifi].v_lcl_addr)) {
                  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;
          if (mb_first->m_pkthdr.len < IP_MINFRAGSIZE)
                  ip_outer->ip_id = 0;
          else
                  ip_outer->ip_id = ip_newid(NULL);
          ip_outer->ip_len = htons(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 |= htons(IP_DF);
          pimhdr = (struct pim_encap_pimhdr *)((char *)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, ntohs(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;
          int ip_tos;
          int iphlen;
  
          iphlen = off;
          datalen = ntohs(ip->ip_len) - iphlen;
  
          /* 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 ahead
           * 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)) == NULL) {
                  log(LOG_ERR, "pim_input: m_pullup failure\n");
                  return;
          }
          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\n");
                  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.
                   */
                  int s;
                  struct sockaddr_in dst = {
                          .sin_len = sizeof(dst),
                          .sin_family = AF_INET,
                  };
                  struct mbuf *mcp;
                  struct ip *encap_ip;
                  u_int32_t *reghdr;
                  struct ifnet *vifp;
  
                  s = splsoftnet();
                  if ((reg_vif_num >= numvifs) || (reg_vif_num == VIFI_INVALID)) {
                          splx(s);
                          if (mrtdebug & DEBUG_PIM)
                                  log(LOG_DEBUG,
                                      "pim_input: register vif not set: %d\n", reg_vif_num);
                          m_freem(m);
                          return;
                  }
                  /* XXX need refcnt? */
                  vifp = viftable[reg_vif_num].v_ifp;
                  splx(s);
  
                  /*
                   * 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 doesn't have options */
                  if (encap_ip->ip_hl != (sizeof(struct ip) >> 2)) {
                          pimstat.pims_rcv_badregisters++;
                          m_freem(m);
                          return;
                  }
  
                  /* verify the inner packet is destined to a mcast group */
                  if (!IN_MULTICAST(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;
                  }
  
                  /* If a NULL_REGISTER, pass it to the daemon */
                  if ((ntohl(*reghdr) & PIM_NULL_REGISTER))
                          goto pim_input_to_daemon;
  
                  /*
                   * 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);
                  }
  
                  /*
                   * 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_copym(m, 0, iphlen + PIM_REG_MINLEN, M_DONTWAIT);
                  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);
                  }
                  /* NB: vifp was collected above; can it change on us? */
                  looutput(vifp, m, (struct sockaddr *)&dst, NULL);
  
                  /* 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.
           */
          /*
           * Currently, pim_input() is always called holding softnet_lock
           * by ipintr()(!NET_MPSAFE) or PR_INPUT_WRAP()(NET_MPSAFE).
           */
          KASSERT(mutex_owned(softnet_lock));
          rip_input(m, iphlen, proto);
  
          return;
  }
  #endif /* PIM */

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