root/usr.sbin/route6d/route6d.c
/*      $KAME: route6d.c,v 1.104 2003/10/31 00:30:20 itojun Exp $       */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project 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 PROJECT 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 PROJECT 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.
 */


#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip6.h>
#include <netinet/udp.h>
#include <err.h>
#include <errno.h>
#include <fnmatch.h>
#include <ifaddrs.h>
#include <netdb.h>
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#include <signal.h>
#include <stdio.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>

#include "route6d.h"

#define MAXFILTER       40
#define RT_DUMP_MAXRETRY        15

#ifdef  DEBUG
#define INIT_INTERVAL6  6
#else
#define INIT_INTERVAL6  10      /* Wait to submit an initial riprequest */
#endif

/* alignment constraint for routing socket */
#define ROUNDUP(a) \
        ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))

struct ifc {                    /* Configuration of an interface */
        TAILQ_ENTRY(ifc) ifc_next;

        char    ifc_name[IFNAMSIZ];             /* if name */
        int     ifc_index;                      /* if index */
        int     ifc_mtu;                        /* if mtu */
        int     ifc_metric;                     /* if metric */
        u_int   ifc_flags;                      /* flags */
        short   ifc_cflags;                     /* IFC_XXX */
        struct  in6_addr ifc_mylladdr;          /* my link-local address */
        struct  sockaddr_in6 ifc_ripsin;        /* rip multicast address */
        TAILQ_HEAD(, ifac) ifc_ifac_head;       /* list of AF_INET6 addrs */
        TAILQ_HEAD(, iff) ifc_iff_head;         /* list of filters */
        int     ifc_joined;                     /* joined to ff02::9 */
};
static TAILQ_HEAD(, ifc) ifc_head = TAILQ_HEAD_INITIALIZER(ifc_head);

struct ifac {                   /* Address associated to an interface */
        TAILQ_ENTRY(ifac) ifac_next;

        struct  ifc *ifac_ifc;          /* back pointer */
        struct  in6_addr ifac_addr;     /* address */
        struct  in6_addr ifac_raddr;    /* remote address, valid in p2p */
        int     ifac_scope_id;          /* scope id */
        int     ifac_plen;              /* prefix length */
};

struct iff {                    /* Filters for an interface */
        TAILQ_ENTRY(iff) iff_next;

        int     iff_type;
        struct  in6_addr iff_addr;
        int     iff_plen;
};

static struct   ifc **index2ifc;
static unsigned int     nindex2ifc;
static struct   ifc *loopifcp = NULL;   /* pointing to loopback */
#ifdef HAVE_POLL_H
static struct   pollfd set[2];
#else
static fd_set   *sockvecp;      /* vector to select() for receiving */
static fd_set   *recvecp;
static int      fdmasks;
static int      maxfd;          /* maximum fd for select() */
#endif
static int      rtsock;         /* the routing socket */
static int      ripsock;        /* socket to send/receive RIP datagram */

static struct   rip6 *ripbuf;   /* packet buffer for sending */

/*
 * Maintain the routes in a linked list.  When the number of the routes
 * grows, somebody would like to introduce a hash based or a radix tree
 * based structure.  I believe the number of routes handled by RIP is
 * limited and I don't have to manage a complex data structure, however.
 *
 * One of the major drawbacks of the linear linked list is the difficulty
 * of representing the relationship between a couple of routes.  This may
 * be a significant problem when we have to support route aggregation with
 * suppressing the specifics covered by the aggregate.
 */

struct riprt {
        TAILQ_ENTRY(riprt) rrt_next;    /* next destination */

        struct  riprt *rrt_same;        /* same destination - future use */
        struct  netinfo6 rrt_info;      /* network info */
        struct  in6_addr rrt_gw;        /* gateway */
        u_long  rrt_flags;              /* kernel routing table flags */
        u_long  rrt_rflags;             /* route6d routing table flags */
        time_t  rrt_t;                  /* when the route validated */
        int     rrt_index;              /* ifindex from which this route got */
};
static TAILQ_HEAD(, riprt) riprt_head = TAILQ_HEAD_INITIALIZER(riprt_head);

static int      dflag = 0;      /* debug flag */
static int      qflag = 0;      /* quiet flag */
static int      nflag = 0;      /* don't update kernel routing table */
static int      aflag = 0;      /* age out even the statically defined routes */
static int      hflag = 0;      /* don't split horizon */
static int      lflag = 0;      /* exchange site local routes */
static int      Pflag = 0;      /* don't age out routes with RTF_PROTO[123] */
static int      Qflag = RTF_PROTO2;     /* set RTF_PROTO[123] flag to routes by RIPng */
static int      sflag = 0;      /* announce static routes w/ split horizon */
static int      Sflag = 0;      /* announce static routes to every interface */
static unsigned long routetag = 0;      /* route tag attached on originating case */

static char     *filter[MAXFILTER];
static int      filtertype[MAXFILTER];
static int      nfilter = 0;

static pid_t    pid;

static struct   sockaddr_storage ripsin;

static int      interval = 1;
static time_t   nextalarm = 0;
#if 0
static time_t   sup_trig_update = 0;
#endif

static FILE     *rtlog = NULL;

static int logopened = 0;

static  int     seq = 0;

static volatile sig_atomic_t seenalrm;
static volatile sig_atomic_t seenquit;
static volatile sig_atomic_t seenusr1;

#define RRTF_AGGREGATE          0x08000000
#define RRTF_NOADVERTISE        0x10000000
#define RRTF_NH_NOT_LLADDR      0x20000000
#define RRTF_SENDANYWAY         0x40000000
#define RRTF_CHANGED            0x80000000

static void sighandler(int);
static void ripalarm(void);
static void riprecv(void);
static void ripsend(struct ifc *, struct sockaddr_in6 *, int);
static int out_filter(struct riprt *, struct ifc *);
static void init(void);
static void ifconfig(void);
static int ifconfig1(const char *, const struct sockaddr *, struct ifc *, int);
static void rtrecv(void);
static int rt_del(const struct sockaddr_in6 *, const struct sockaddr_in6 *,
        const struct sockaddr_in6 *);
static int rt_deladdr(struct ifc *, const struct sockaddr_in6 *,
        const struct sockaddr_in6 *);
static void filterconfig(void);
static int getifmtu(int);
static const char *rttypes(struct rt_msghdr *);
static const char *rtflags(struct rt_msghdr *);
static const char *ifflags(int);
static int ifrt(struct ifc *, int);
static void ifrt_p2p(struct ifc *, int);
static void applyplen(struct in6_addr *, int);
static void ifrtdump(int);
static void ifdump(int);
static void ifdump0(FILE *, const struct ifc *);
static void ifremove(int);
static void rtdump(int);
static void rt_entry(struct rt_msghdr *, int);
static void rtdexit(void);
static void riprequest(struct ifc *, struct netinfo6 *, int,
        struct sockaddr_in6 *);
static void ripflush(struct ifc *, struct sockaddr_in6 *, int, struct netinfo6 *np);
static void sendrequest(struct ifc *);
static int sin6mask2len(const struct sockaddr_in6 *);
static int mask2len(const struct in6_addr *, int);
static int sendpacket(struct sockaddr_in6 *, int);
static int addroute(struct riprt *, const struct in6_addr *, struct ifc *);
static int delroute(struct netinfo6 *, struct in6_addr *);
#if 0
static struct in6_addr *getroute(struct netinfo6 *, struct in6_addr *);
#endif
static void krtread(int);
static int tobeadv(struct riprt *, struct ifc *);
static char *allocopy(char *);
static char *hms(void);
static const char *inet6_n2p(const struct in6_addr *);
static struct ifac *ifa_match(const struct ifc *, const struct in6_addr *, int);
static struct in6_addr *plen2mask(int);
static struct riprt *rtsearch(struct netinfo6 *);
static int ripinterval(int);
#if 0
static time_t ripsuptrig(void);
#endif
static void fatal(const char *, ...)
        __attribute__((__format__(__printf__, 1, 2)));
static void trace(int, const char *, ...)
        __attribute__((__format__(__printf__, 2, 3)));
static void tracet(int, const char *, ...)
        __attribute__((__format__(__printf__, 2, 3)));
static struct ifc *ifc_find(char *);
static struct iff *iff_find(struct ifc *, int);
static void setindex2ifc(int, struct ifc *);

#define MALLOC(type)    ((type *)malloc(sizeof(type)))

#define IFIL_TYPE_ANY   0x0
#define IFIL_TYPE_A     'A'
#define IFIL_TYPE_N     'N'
#define IFIL_TYPE_T     'T'
#define IFIL_TYPE_O     'O'
#define IFIL_TYPE_L     'L'

int
main(int argc, char *argv[])
{
        int     ch;
        int     error = 0;
        unsigned long proto;
        struct  ifc *ifcp;
        sigset_t mask, omask;
        const char *pidfile = ROUTE6D_PID;
        FILE *pidfh;
        char *progname;
        char *ep;

        progname = strrchr(*argv, '/');
        if (progname)
                progname++;
        else
                progname = *argv;

        pid = getpid();
        while ((ch = getopt(argc, argv, "A:N:O:R:T:L:t:adDhlnp:P:Q:qsS")) != -1) {
                switch (ch) {
                case 'A':
                case 'N':
                case 'O':
                case 'T':
                case 'L':
                        if (nfilter >= MAXFILTER) {
                                fatal("Exceeds MAXFILTER");
                                /*NOTREACHED*/
                        }
                        filtertype[nfilter] = ch;
                        filter[nfilter++] = allocopy(optarg);
                        break;
                case 't':
                        ep = NULL;
                        routetag = strtoul(optarg, &ep, 0);
                        if (!ep || *ep != '\0' || (routetag & ~0xffff) != 0) {
                                fatal("invalid route tag");
                                /*NOTREACHED*/
                        }
                        break;
                case 'p':
                        pidfile = optarg;
                        break;
                case 'P':
                        ep = NULL;
                        proto = strtoul(optarg, &ep, 0);
                        if (!ep || *ep != '\0' || 3 < proto) {
                                fatal("invalid P flag");
                                /*NOTREACHED*/
                        }
                        if (proto == 0)
                                Pflag = 0;
                        if (proto == 1)
                                Pflag |= RTF_PROTO1;
                        if (proto == 2)
                                Pflag |= RTF_PROTO2;
                        if (proto == 3)
                                Pflag |= RTF_PROTO3;
                        break;
                case 'Q':
                        ep = NULL;
                        proto = strtoul(optarg, &ep, 0);
                        if (!ep || *ep != '\0' || 3 < proto) {
                                fatal("invalid Q flag");
                                /*NOTREACHED*/
                        }
                        if (proto == 0)
                                Qflag = 0;
                        if (proto == 1)
                                Qflag |= RTF_PROTO1;
                        if (proto == 2)
                                Qflag |= RTF_PROTO2;
                        if (proto == 3)
                                Qflag |= RTF_PROTO3;
                        break;
                case 'R':
                        if ((rtlog = fopen(optarg, "w")) == NULL) {
                                fatal("Can not write to routelog");
                                /*NOTREACHED*/
                        }
                        break;
#define FLAG(c, flag, n)        case c: do { flag = n; break; } while(0)
                FLAG('a', aflag, 1); break;
                FLAG('d', dflag, 1); break;
                FLAG('D', dflag, 2); break;
                FLAG('h', hflag, 1); break;
                FLAG('l', lflag, 1); break;
                FLAG('n', nflag, 1); break;
                FLAG('q', qflag, 1); break;
                FLAG('s', sflag, 1); break;
                FLAG('S', Sflag, 1); break;
#undef  FLAG
                default:
                        fatal("Invalid option specified, terminating");
                        /*NOTREACHED*/
                }
        }
        argc -= optind;
        argv += optind;
        if (argc > 0) {
                fatal("bogus extra arguments");
                /*NOTREACHED*/
        }

        if (geteuid()) {
                nflag = 1;
                fprintf(stderr, "No kernel update is allowed\n");
        }

        if (dflag == 0) {
                if (daemon(0, 0) < 0) {
                        fatal("daemon");
                        /*NOTREACHED*/
                }
        }

        openlog(progname, LOG_NDELAY|LOG_PID, LOG_DAEMON);
        logopened++;

        if ((ripbuf = (struct rip6 *)malloc(RIP6_MAXMTU)) == NULL)
                fatal("malloc");
        memset(ripbuf, 0, RIP6_MAXMTU);
        ripbuf->rip6_cmd = RIP6_RESPONSE;
        ripbuf->rip6_vers = RIP6_VERSION;
        ripbuf->rip6_res1[0] = 0;
        ripbuf->rip6_res1[1] = 0;

        init();
        ifconfig();
        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                if (ifcp->ifc_index < 0) {
                        fprintf(stderr, "No ifindex found at %s "
                            "(no link-local address?)\n", ifcp->ifc_name);
                        error++;
                }
        }
        if (error)
                exit(1);
        if (loopifcp == NULL) {
                fatal("No loopback found");
                /*NOTREACHED*/
        }
        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                ifrt(ifcp, 0);
        }
        filterconfig();
        krtread(0);
        if (dflag)
                ifrtdump(0);

        pid = getpid();
        if ((pidfh = fopen(pidfile, "w")) != NULL) {
                fprintf(pidfh, "%d\n", pid);
                fclose(pidfh);
        }

        if ((ripbuf = (struct rip6 *)malloc(RIP6_MAXMTU)) == NULL) {
                fatal("malloc");
                /*NOTREACHED*/
        }
        memset(ripbuf, 0, RIP6_MAXMTU);
        ripbuf->rip6_cmd = RIP6_RESPONSE;
        ripbuf->rip6_vers = RIP6_VERSION;
        ripbuf->rip6_res1[0] = 0;
        ripbuf->rip6_res1[1] = 0;

        if (signal(SIGALRM, sighandler) == SIG_ERR ||
            signal(SIGQUIT, sighandler) == SIG_ERR ||
            signal(SIGTERM, sighandler) == SIG_ERR ||
            signal(SIGUSR1, sighandler) == SIG_ERR ||
            signal(SIGHUP, sighandler) == SIG_ERR ||
            signal(SIGINT, sighandler) == SIG_ERR) {
                fatal("signal");
                /*NOTREACHED*/
        }
        /*
         * To avoid rip packet congestion (not on a cable but in this
         * process), wait for a moment to send the first RIP6_RESPONSE
         * packets.
         */
        alarm(ripinterval(INIT_INTERVAL6));

        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                if (iff_find(ifcp, IFIL_TYPE_N) != NULL)
                        continue;
                if (ifcp->ifc_index > 0 && (ifcp->ifc_flags & IFF_UP))
                        sendrequest(ifcp);
        }

        syslog(LOG_INFO, "**** Started ****");
        sigemptyset(&mask);
        sigaddset(&mask, SIGALRM);
        while (1) {
                if (seenalrm) {
                        ripalarm();
                        seenalrm = 0;
                        continue;
                }
                if (seenquit) {
                        rtdexit();
                        seenquit = 0;
                        continue;
                }
                if (seenusr1) {
                        ifrtdump(SIGUSR1);
                        seenusr1 = 0;
                        continue;
                }

#ifdef HAVE_POLL_H
                switch (poll(set, 2, INFTIM))
#else
                memcpy(recvecp, sockvecp, fdmasks);
                switch (select(maxfd + 1, recvecp, 0, 0, 0))
#endif
                {
                case -1:
                        if (errno != EINTR) {
                                fatal("select");
                                /*NOTREACHED*/
                        }
                        continue;
                case 0:
                        continue;
                default:
#ifdef HAVE_POLL_H
                        if (set[0].revents & POLLIN)
#else
                        if (FD_ISSET(ripsock, recvecp))
#endif
                        {
                                sigprocmask(SIG_BLOCK, &mask, &omask);
                                riprecv();
                                sigprocmask(SIG_SETMASK, &omask, NULL);
                        }
#ifdef HAVE_POLL_H
                        if (set[1].revents & POLLIN)
#else
                        if (FD_ISSET(rtsock, recvecp))
#endif
                        {
                                sigprocmask(SIG_BLOCK, &mask, &omask);
                                rtrecv();
                                sigprocmask(SIG_SETMASK, &omask, NULL);
                        }
                }
        }
}

static void
sighandler(int signo)
{

        switch (signo) {
        case SIGALRM:
                seenalrm++;
                break;
        case SIGQUIT:
        case SIGTERM:
                seenquit++;
                break;
        case SIGUSR1:
        case SIGHUP:
        case SIGINT:
                seenusr1++;
                break;
        }
}

/*
 * gracefully exits after resetting sockopts.
 */
/* ARGSUSED */
static void
rtdexit(void)
{
        struct  riprt *rrt;

        alarm(0);
        TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                if (rrt->rrt_rflags & RRTF_AGGREGATE) {
                        delroute(&rrt->rrt_info, &rrt->rrt_gw);
                }
        }
        close(ripsock);
        close(rtsock);
        syslog(LOG_INFO, "**** Terminated ****");
        closelog();
        exit(1);
}

/*
 * Called periodically:
 *      1. age out the learned route. remove it if necessary.
 *      2. submit RIP6_RESPONSE packets.
 * Invoked in every SUPPLY_INTERVAL6 (30) seconds.  I believe we don't have
 * to invoke this function in every 1 or 5 or 10 seconds only to age the
 * routes more precisely.
 */
/* ARGSUSED */
static void
ripalarm(void)
{
        struct  ifc *ifcp;
        struct  riprt *rrt, *rrt_tmp;
        time_t  t_lifetime, t_holddown;

        /* age the RIP routes */
        t_lifetime = time(NULL) - RIP_LIFETIME;
        t_holddown = t_lifetime - RIP_HOLDDOWN;
        TAILQ_FOREACH_SAFE(rrt, &riprt_head, rrt_next, rrt_tmp) {
                if (rrt->rrt_t == 0)
                        continue;
                else if (rrt->rrt_t < t_holddown) {
                        TAILQ_REMOVE(&riprt_head, rrt, rrt_next);
                        delroute(&rrt->rrt_info, &rrt->rrt_gw);
                        free(rrt);
                } else if (rrt->rrt_t < t_lifetime)
                        rrt->rrt_info.rip6_metric = HOPCNT_INFINITY6;
        }
        /* Supply updates */
        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                if (ifcp->ifc_index > 0 && (ifcp->ifc_flags & IFF_UP))
                        ripsend(ifcp, &ifcp->ifc_ripsin, 0);
        }
        alarm(ripinterval(SUPPLY_INTERVAL6));
}

static void
init(void)
{
        int     error;
        const int int0 = 0, int1 = 1, int255 = 255;
        struct  addrinfo hints, *res;
        char    port[NI_MAXSERV];

        TAILQ_INIT(&ifc_head);
        nindex2ifc = 0; /*initial guess*/
        index2ifc = NULL;
        snprintf(port, sizeof(port), "%u", RIP6_PORT);

        memset(&hints, 0, sizeof(hints));
        hints.ai_family = PF_INET6;
        hints.ai_socktype = SOCK_DGRAM;
        hints.ai_protocol = IPPROTO_UDP;
        hints.ai_flags = AI_PASSIVE;
        error = getaddrinfo(NULL, port, &hints, &res);
        if (error) {
                fatal("%s", gai_strerror(error));
                /*NOTREACHED*/
        }
        if (res->ai_next) {
                fatal(":: resolved to multiple address");
                /*NOTREACHED*/
        }

        ripsock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
        if (ripsock < 0) {
                fatal("rip socket");
                /*NOTREACHED*/
        }
#ifdef IPV6_V6ONLY
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_V6ONLY,
            &int1, sizeof(int1)) < 0) {
                fatal("rip IPV6_V6ONLY");
                /*NOTREACHED*/
        }
#endif
        if (bind(ripsock, res->ai_addr, res->ai_addrlen) < 0) {
                fatal("rip bind");
                /*NOTREACHED*/
        }
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
            &int255, sizeof(int255)) < 0) {
                fatal("rip IPV6_MULTICAST_HOPS");
                /*NOTREACHED*/
        }
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
            &int0, sizeof(int0)) < 0) {
                fatal("rip IPV6_MULTICAST_LOOP");
                /*NOTREACHED*/
        }

#ifdef IPV6_RECVPKTINFO
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_RECVPKTINFO,
            &int1, sizeof(int1)) < 0) {
                fatal("rip IPV6_RECVPKTINFO");
                /*NOTREACHED*/
        }
#else  /* old adv. API */
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_PKTINFO,
            &int1, sizeof(int1)) < 0) {
                fatal("rip IPV6_PKTINFO");
                /*NOTREACHED*/
        }
#endif

#ifdef IPV6_RECVPKTINFO
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT,
            &int1, sizeof(int1)) < 0) {
                fatal("rip IPV6_RECVHOPLIMIT");
                /*NOTREACHED*/
        }
#else  /* old adv. API */
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_HOPLIMIT,
            &int1, sizeof(int1)) < 0) {
                fatal("rip IPV6_HOPLIMIT");
                /*NOTREACHED*/
        }
#endif
        freeaddrinfo(res);

        memset(&hints, 0, sizeof(hints));
        hints.ai_family = PF_INET6;
        hints.ai_socktype = SOCK_DGRAM;
        hints.ai_protocol = IPPROTO_UDP;
        error = getaddrinfo(RIP6_DEST, port, &hints, &res);
        if (error) {
                fatal("%s", gai_strerror(error));
                /*NOTREACHED*/
        }
        if (res->ai_next) {
                fatal("%s resolved to multiple address", RIP6_DEST);
                /*NOTREACHED*/
        }
        memcpy(&ripsin, res->ai_addr, res->ai_addrlen);
        freeaddrinfo(res);

#ifdef HAVE_POLL_H
        set[0].fd = ripsock;
        set[0].events = POLLIN;
#else
        maxfd = ripsock;
#endif

        if (nflag == 0) {
                if ((rtsock = socket(PF_ROUTE, SOCK_RAW, 0)) < 0) {
                        fatal("route socket");
                        /*NOTREACHED*/
                }
#ifdef HAVE_POLL_H
                set[1].fd = rtsock;
                set[1].events = POLLIN;
#else
                if (rtsock > maxfd)
                        maxfd = rtsock;
#endif
        } else {
#ifdef HAVE_POLL_H
                set[1].fd = -1;
#else
                rtsock = -1;    /*just for safety */
#endif
        }

#ifndef HAVE_POLL_H
        fdmasks = howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask);
        if ((sockvecp = malloc(fdmasks)) == NULL) {
                fatal("malloc");
                /*NOTREACHED*/
        }
        if ((recvecp = malloc(fdmasks)) == NULL) {
                fatal("malloc");
                /*NOTREACHED*/
        }
        memset(sockvecp, 0, fdmasks);
        FD_SET(ripsock, sockvecp);
        if (rtsock >= 0)
                FD_SET(rtsock, sockvecp);
#endif
}

#define RIPSIZE(n) \
        (sizeof(struct rip6) + ((n)-1) * sizeof(struct netinfo6))

/*
 * ripflush flushes the rip datagram stored in the rip buffer
 */
static void
ripflush(struct ifc *ifcp, struct sockaddr_in6 *sin6, int nrt, struct netinfo6 *np)
{
        int i;
        int error;

        if (ifcp)
                tracet(1, "Send(%s): info(%d) to %s.%d\n",
                        ifcp->ifc_name, nrt,
                        inet6_n2p(&sin6->sin6_addr), ntohs(sin6->sin6_port));
        else
                tracet(1, "Send: info(%d) to %s.%d\n",
                        nrt, inet6_n2p(&sin6->sin6_addr), ntohs(sin6->sin6_port));
        if (dflag >= 2) {
                np = ripbuf->rip6_nets;
                for (i = 0; i < nrt; i++, np++) {
                        if (np->rip6_metric == NEXTHOP_METRIC) {
                                if (IN6_IS_ADDR_UNSPECIFIED(&np->rip6_dest))
                                        trace(2, "    NextHop reset");
                                else {
                                        trace(2, "    NextHop %s",
                                                inet6_n2p(&np->rip6_dest));
                                }
                        } else {
                                trace(2, "    %s/%d[%d]",
                                        inet6_n2p(&np->rip6_dest),
                                        np->rip6_plen, np->rip6_metric);
                        }
                        if (np->rip6_tag) {
                                trace(2, "  tag=0x%04x",
                                        ntohs(np->rip6_tag) & 0xffff);
                        }
                        trace(2, "\n");
                }
        }
        error = sendpacket(sin6, RIPSIZE(nrt));
        if (error == EAFNOSUPPORT) {
                /* Protocol not supported */
                if (ifcp != NULL) {
                        tracet(1, "Could not send info to %s (%s): "
                            "set IFF_UP to 0\n",
                            ifcp->ifc_name,
                            inet6_n2p(&ifcp->ifc_ripsin.sin6_addr));
                        /* As if down for AF_INET6 */
                        ifcp->ifc_flags &= ~IFF_UP;
                } else {
                        tracet(1, "Could not send info to %s\n",
                            inet6_n2p(&sin6->sin6_addr));
                }
        }
}

/*
 * Generate RIP6_RESPONSE packets and send them.
 */
static void
ripsend(struct  ifc *ifcp, struct sockaddr_in6 *sin6, int flag)
{
        struct  riprt *rrt;
        struct  in6_addr *nh;   /* next hop */
        struct netinfo6 *np;
        int     maxrte;
        int nrt;

        if (qflag)
                return;

        if (ifcp == NULL) {
                /*
                 * Request from non-link local address is not
                 * a regular route6d update.
                 */
                maxrte = (IFMINMTU - sizeof(struct ip6_hdr) -
                                sizeof(struct udphdr) -
                                sizeof(struct rip6) + sizeof(struct netinfo6)) /
                                sizeof(struct netinfo6);
                nh = NULL;
                nrt = 0;
                np = ripbuf->rip6_nets;
                TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                        if (rrt->rrt_rflags & RRTF_NOADVERTISE)
                                continue;
                        /* Put the route to the buffer */
                        *np = rrt->rrt_info;
                        np++; nrt++;
                        if (nrt == maxrte) {
                                ripflush(NULL, sin6, nrt, np);
                                nh = NULL;
                                nrt = 0;
                                np = ripbuf->rip6_nets;
                        }
                }
                if (nrt)        /* Send last packet */
                        ripflush(NULL, sin6, nrt, np);
                return;
        }

        if ((flag & RRTF_SENDANYWAY) == 0 &&
            (qflag || (ifcp->ifc_flags & IFF_LOOPBACK)))
                return;

        /* -N: no use */
        if (iff_find(ifcp, IFIL_TYPE_N) != NULL)
                return;

        /* -T: generate default route only */
        if (iff_find(ifcp, IFIL_TYPE_T) != NULL) {
                struct netinfo6 rrt_info;
                memset(&rrt_info, 0, sizeof(struct netinfo6));
                rrt_info.rip6_dest = in6addr_any;
                rrt_info.rip6_plen = 0;
                rrt_info.rip6_metric = 1;
                rrt_info.rip6_metric += ifcp->ifc_metric;
                rrt_info.rip6_tag = htons(routetag & 0xffff);
                np = ripbuf->rip6_nets;
                *np = rrt_info;
                nrt = 1;
                ripflush(ifcp, sin6, nrt, np);
                return;
        }

        maxrte = (ifcp->ifc_mtu - sizeof(struct ip6_hdr) -
                        sizeof(struct udphdr) -
                        sizeof(struct rip6) + sizeof(struct netinfo6)) /
                        sizeof(struct netinfo6);

        nrt = 0; np = ripbuf->rip6_nets; nh = NULL;
        TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                if (rrt->rrt_rflags & RRTF_NOADVERTISE)
                        continue;

                /* Need to check filter here */
                if (out_filter(rrt, ifcp) == 0)
                        continue;

                /* Check split horizon and other conditions */
                if (tobeadv(rrt, ifcp) == 0)
                        continue;

                /* Only considers the routes with flag if specified */
                if ((flag & RRTF_CHANGED) &&
                    (rrt->rrt_rflags & RRTF_CHANGED) == 0)
                        continue;

                /* Check nexthop */
                if (rrt->rrt_index == ifcp->ifc_index &&
                    !IN6_IS_ADDR_UNSPECIFIED(&rrt->rrt_gw) &&
                    (rrt->rrt_rflags & RRTF_NH_NOT_LLADDR) == 0) {
                        if (nh == NULL || !IN6_ARE_ADDR_EQUAL(nh, &rrt->rrt_gw)) {
                                if (nrt == maxrte - 2) {
                                        ripflush(ifcp, sin6, nrt, np);
                                        nh = NULL;
                                        nrt = 0;
                                        np = ripbuf->rip6_nets;
                                }

                                np->rip6_dest = rrt->rrt_gw;
                                np->rip6_plen = 0;
                                np->rip6_tag = 0;
                                np->rip6_metric = NEXTHOP_METRIC;
                                nh = &rrt->rrt_gw;
                                np++; nrt++;
                        }
                } else if (nh && (rrt->rrt_index != ifcp->ifc_index ||
                                  !IN6_ARE_ADDR_EQUAL(nh, &rrt->rrt_gw) ||
                                  rrt->rrt_rflags & RRTF_NH_NOT_LLADDR)) {
                        /* Reset nexthop */
                        if (nrt == maxrte - 2) {
                                ripflush(ifcp, sin6, nrt, np);
                                nh = NULL;
                                nrt = 0;
                                np = ripbuf->rip6_nets;
                        }
                        memset(np, 0, sizeof(struct netinfo6));
                        np->rip6_metric = NEXTHOP_METRIC;
                        nh = NULL;
                        np++; nrt++;
                }

                /* Put the route to the buffer */
                *np = rrt->rrt_info;
                np++; nrt++;
                if (nrt == maxrte) {
                        ripflush(ifcp, sin6, nrt, np);
                        nh = NULL;
                        nrt = 0;
                        np = ripbuf->rip6_nets;
                }
        }
        if (nrt)        /* Send last packet */
                ripflush(ifcp, sin6, nrt, np);
}

/*
 * outbound filter logic, per-route/interface.
 */
static int
out_filter(struct riprt *rrt, struct ifc *ifcp)
{
        struct iff *iffp;
        struct in6_addr ia;
        int ok;

        /*
         * -A: filter out less specific routes, if we have aggregated
         * route configured.
         */
        TAILQ_FOREACH(iffp, &ifcp->ifc_iff_head, iff_next) {
                if (iffp->iff_type != 'A')
                        continue;
                if (rrt->rrt_info.rip6_plen <= iffp->iff_plen)
                        continue;
                ia = rrt->rrt_info.rip6_dest;
                applyplen(&ia, iffp->iff_plen);
                if (IN6_ARE_ADDR_EQUAL(&ia, &iffp->iff_addr))
                        return 0;
        }

        /*
         * if it is an aggregated route, advertise it only to the
         * interfaces specified on -A.
         */
        if ((rrt->rrt_rflags & RRTF_AGGREGATE) != 0) {
                ok = 0;
                TAILQ_FOREACH(iffp, &ifcp->ifc_iff_head, iff_next) {
                        if (iffp->iff_type != 'A')
                                continue;
                        if (rrt->rrt_info.rip6_plen == iffp->iff_plen &&
                            IN6_ARE_ADDR_EQUAL(&rrt->rrt_info.rip6_dest,
                            &iffp->iff_addr)) {
                                ok = 1;
                                break;
                        }
                }
                if (!ok)
                        return 0;
        }

        /*
         * -O: advertise only if prefix matches the configured prefix.
         */
        if (iff_find(ifcp, IFIL_TYPE_O) != NULL) {
                ok = 0;
                TAILQ_FOREACH(iffp, &ifcp->ifc_iff_head, iff_next) {
                        if (iffp->iff_type != 'O')
                                continue;
                        if (rrt->rrt_info.rip6_plen < iffp->iff_plen)
                                continue;
                        ia = rrt->rrt_info.rip6_dest;
                        applyplen(&ia, iffp->iff_plen);
                        if (IN6_ARE_ADDR_EQUAL(&ia, &iffp->iff_addr)) {
                                ok = 1;
                                break;
                        }
                }
                if (!ok)
                        return 0;
        }

        /* the prefix should be advertised */
        return 1;
}

/*
 * Determine if the route is to be advertised on the specified interface.
 * It checks options specified in the arguments and the split horizon rule.
 */
static int
tobeadv(struct riprt *rrt, struct ifc *ifcp)
{

        /* Special care for static routes */
        if (rrt->rrt_flags & RTF_STATIC) {
                /* XXX don't advertise reject/blackhole routes */
                if (rrt->rrt_flags & (RTF_REJECT | RTF_BLACKHOLE))
                        return 0;

                if (Sflag)      /* Yes, advertise it anyway */
                        return 1;
                if (sflag && rrt->rrt_index != ifcp->ifc_index)
                        return 1;
                return 0;
        }
        /* Regular split horizon */
        if (hflag == 0 && rrt->rrt_index == ifcp->ifc_index)
                return 0;
        return 1;
}

/*
 * Send a rip packet actually.
 */
static int
sendpacket(struct sockaddr_in6 *sin6, int len)
{
        struct msghdr m;
        struct cmsghdr *cm;
        struct iovec iov[2];
        struct in6_pktinfo *pi;
        u_char cmsgbuf[256];
        int idx;
        struct sockaddr_in6 sincopy;

        /* do not overwrite the given sin */
        sincopy = *sin6;
        sin6 = &sincopy;

        if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
            IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
                idx = sin6->sin6_scope_id;
        else
                idx = 0;

        m.msg_name = (caddr_t)sin6;
        m.msg_namelen = sizeof(*sin6);
        iov[0].iov_base = (caddr_t)ripbuf;
        iov[0].iov_len = len;
        m.msg_iov = iov;
        m.msg_iovlen = 1;
        m.msg_flags = 0;
        if (!idx) {
                m.msg_control = NULL;
                m.msg_controllen = 0;
        } else {
                memset(cmsgbuf, 0, sizeof(cmsgbuf));
                cm = (struct cmsghdr *)(void *)cmsgbuf;
                m.msg_control = (caddr_t)cm;
                m.msg_controllen = CMSG_SPACE(sizeof(struct in6_pktinfo));

                cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
                cm->cmsg_level = IPPROTO_IPV6;
                cm->cmsg_type = IPV6_PKTINFO;
                pi = (struct in6_pktinfo *)(void *)CMSG_DATA(cm);
                memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr)); /*::*/
                pi->ipi6_ifindex = idx;
        }

        if (sendmsg(ripsock, &m, 0 /*MSG_DONTROUTE*/) < 0) {
                trace(1, "sendmsg: %s\n", strerror(errno));
                return errno;
        }

        return 0;
}

/*
 * Receive and process RIP packets.  Update the routes/kernel forwarding
 * table if necessary.
 */
static void
riprecv(void)
{
        struct  ifc *ifcp, *ic;
        struct  sockaddr_in6 fsock;
        struct  in6_addr nh;    /* next hop */
        struct  rip6 *rp;
        struct  netinfo6 *np, *nq;
        struct  riprt *rrt;
        ssize_t len, nn;
        unsigned int need_trigger, idx;
        char    buf[4 * RIP6_MAXMTU];
        time_t  t;
        struct msghdr m;
        struct cmsghdr *cm;
        struct iovec iov[2];
        u_char cmsgbuf[256];
        struct in6_pktinfo *pi = NULL;
        int *hlimp = NULL;
        struct iff *iffp;
        struct in6_addr ia;
        int ok;
        time_t t_half_lifetime;

        need_trigger = 0;

        m.msg_name = (caddr_t)&fsock;
        m.msg_namelen = sizeof(fsock);
        iov[0].iov_base = (caddr_t)buf;
        iov[0].iov_len = sizeof(buf);
        m.msg_iov = iov;
        m.msg_iovlen = 1;
        cm = (struct cmsghdr *)(void *)cmsgbuf;
        m.msg_control = (caddr_t)cm;
        m.msg_controllen = sizeof(cmsgbuf);
        m.msg_flags = 0;
        if ((len = recvmsg(ripsock, &m, 0)) < 0) {
                fatal("recvmsg");
                /*NOTREACHED*/
        }
        idx = 0;
        for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&m);
             cm;
             cm = (struct cmsghdr *)CMSG_NXTHDR(&m, cm)) {
                if (cm->cmsg_level != IPPROTO_IPV6)
                    continue;
                switch (cm->cmsg_type) {
                case IPV6_PKTINFO:
                        if (cm->cmsg_len != CMSG_LEN(sizeof(*pi))) {
                                trace(1,
                                    "invalid cmsg length for IPV6_PKTINFO\n");
                                return;
                        }
                        pi = (struct in6_pktinfo *)(void *)CMSG_DATA(cm);
                        idx = pi->ipi6_ifindex;
                        break;
                case IPV6_HOPLIMIT:
                        if (cm->cmsg_len != CMSG_LEN(sizeof(int))) {
                                trace(1,
                                    "invalid cmsg length for IPV6_HOPLIMIT\n");
                                return;
                        }
                        hlimp = (int *)(void *)CMSG_DATA(cm);
                        break;
                }
        }

        if ((size_t)len < sizeof(struct rip6)) {
                trace(1, "Packet too short\n");
                return;
        }

        if (pi == NULL || hlimp == NULL) {
                /*
                 * This can happen when the kernel failed to allocate memory
                 * for the ancillary data.  Although we might be able to handle
                 * some cases without this info, those are minor and not so
                 * important, so it's better to discard the packet for safer
                 * operation.
                 */
                trace(1, "IPv6 packet information cannot be retrieved\n");
                return;
        }

        nh = fsock.sin6_addr;
        nn = (len - sizeof(struct rip6) + sizeof(struct netinfo6)) /
                sizeof(struct netinfo6);
        rp = (struct rip6 *)(void *)buf;
        np = rp->rip6_nets;

        if (rp->rip6_vers != RIP6_VERSION) {
                trace(1, "Incorrect RIP version %d\n", rp->rip6_vers);
                return;
        }
        if (rp->rip6_cmd == RIP6_REQUEST) {
                if (idx && idx < nindex2ifc) {
                        ifcp = index2ifc[idx];
                        riprequest(ifcp, np, nn, &fsock);
                } else {
                        riprequest(NULL, np, nn, &fsock);
                }
                return;
        }

        if (!IN6_IS_ADDR_LINKLOCAL(&fsock.sin6_addr)) {
                trace(1, "Response from non-ll addr: %s\n",
                    inet6_n2p(&fsock.sin6_addr));
                return;         /* Ignore packets from non-link-local addr */
        }
        if (ntohs(fsock.sin6_port) != RIP6_PORT) {
                trace(1, "Response from non-rip port from %s\n",
                    inet6_n2p(&fsock.sin6_addr));
                return;
        }
        if (IN6_IS_ADDR_MULTICAST(&pi->ipi6_addr) && *hlimp != 255) {
                trace(1,
                    "Response packet with a smaller hop limit (%d) from %s\n",
                    *hlimp, inet6_n2p(&fsock.sin6_addr));
                return;
        }
        /*
         * Further validation: since this program does not send off-link
         * requests, an incoming response must always come from an on-link
         * node.  Although this is normally ensured by the source address
         * check above, it may not 100% be safe because there are router
         * implementations that (invalidly) allow a packet with a link-local
         * source address to be forwarded to a different link.
         * So we also check whether the destination address is a link-local
         * address or the hop limit is 255.  Note that RFC2080 does not require
         * the specific hop limit for a unicast response, so we cannot assume
         * the limitation.
         */
        if (!IN6_IS_ADDR_LINKLOCAL(&pi->ipi6_addr) && *hlimp != 255) {
                trace(1,
                    "Response packet possibly from an off-link node: "
                    "from %s to %s hlim=%d\n",
                    inet6_n2p(&fsock.sin6_addr),
                    inet6_n2p(&pi->ipi6_addr), *hlimp);
                return;
        }

        idx = fsock.sin6_scope_id;
        ifcp = (idx < nindex2ifc) ? index2ifc[idx] : NULL;
        if (!ifcp) {
                trace(1, "Packets to unknown interface index %d\n", idx);
                return;         /* Ignore it */
        }
        if (IN6_ARE_ADDR_EQUAL(&ifcp->ifc_mylladdr, &fsock.sin6_addr))
                return;         /* The packet is from me; ignore */
        if (rp->rip6_cmd != RIP6_RESPONSE) {
                trace(1, "Invalid command %d\n", rp->rip6_cmd);
                return;
        }

        /* -N: no use */
        if (iff_find(ifcp, IFIL_TYPE_N) != NULL)
                return;

        tracet(1, "Recv(%s): from %s.%d info(%zd)\n",
            ifcp->ifc_name, inet6_n2p(&nh), ntohs(fsock.sin6_port), nn);

        t = time(NULL);
        t_half_lifetime = t - (RIP_LIFETIME/2);
        for (; nn; nn--, np++) {
                if (np->rip6_metric == NEXTHOP_METRIC) {
                        /* modify neighbor address */
                        if (IN6_IS_ADDR_LINKLOCAL(&np->rip6_dest)) {
                                nh = np->rip6_dest;
                                trace(1, "\tNexthop: %s\n", inet6_n2p(&nh));
                        } else if (IN6_IS_ADDR_UNSPECIFIED(&np->rip6_dest)) {
                                nh = fsock.sin6_addr;
                                trace(1, "\tNexthop: %s\n", inet6_n2p(&nh));
                        } else {
                                nh = fsock.sin6_addr;
                                trace(1, "\tInvalid Nexthop: %s\n",
                                    inet6_n2p(&np->rip6_dest));
                        }
                        continue;
                }
                if (IN6_IS_ADDR_MULTICAST(&np->rip6_dest)) {
                        trace(1, "\tMulticast netinfo6: %s/%d [%d]\n",
                                inet6_n2p(&np->rip6_dest),
                                np->rip6_plen, np->rip6_metric);
                        continue;
                }
                if (IN6_IS_ADDR_LOOPBACK(&np->rip6_dest)) {
                        trace(1, "\tLoopback netinfo6: %s/%d [%d]\n",
                                inet6_n2p(&np->rip6_dest),
                                np->rip6_plen, np->rip6_metric);
                        continue;
                }
                if (IN6_IS_ADDR_LINKLOCAL(&np->rip6_dest)) {
                        trace(1, "\tLink Local netinfo6: %s/%d [%d]\n",
                                inet6_n2p(&np->rip6_dest),
                                np->rip6_plen, np->rip6_metric);
                        continue;
                }
                /* may need to pass sitelocal prefix in some case, however*/
                if (IN6_IS_ADDR_SITELOCAL(&np->rip6_dest) && !lflag) {
                        trace(1, "\tSite Local netinfo6: %s/%d [%d]\n",
                                inet6_n2p(&np->rip6_dest),
                                np->rip6_plen, np->rip6_metric);
                        continue;
                }
                trace(2, "\tnetinfo6: %s/%d [%d]",
                        inet6_n2p(&np->rip6_dest),
                        np->rip6_plen, np->rip6_metric);
                if (np->rip6_tag)
                        trace(2, "  tag=0x%04x", ntohs(np->rip6_tag) & 0xffff);
                if (dflag >= 2) {
                        ia = np->rip6_dest;
                        applyplen(&ia, np->rip6_plen);
                        if (!IN6_ARE_ADDR_EQUAL(&ia, &np->rip6_dest))
                                trace(2, " [junk outside prefix]");
                }

                /*
                 * -L: listen only if the prefix matches the configuration
                 */
                ok = 1; /* if there's no L filter, it is ok */
                TAILQ_FOREACH(iffp, &ifcp->ifc_iff_head, iff_next) {
                        if (iffp->iff_type != IFIL_TYPE_L)
                                continue;
                        ok = 0;
                        if (np->rip6_plen < iffp->iff_plen)
                                continue;
                        /* special rule: ::/0 means default, not "in /0" */
                        if (iffp->iff_plen == 0 && np->rip6_plen > 0)
                                continue;
                        ia = np->rip6_dest;
                        applyplen(&ia, iffp->iff_plen);
                        if (IN6_ARE_ADDR_EQUAL(&ia, &iffp->iff_addr)) {
                                ok = 1;
                                break;
                        }
                }
                if (!ok) {
                        trace(2, "  (filtered)\n");
                        continue;
                }

                trace(2, "\n");
                np->rip6_metric++;
                np->rip6_metric += ifcp->ifc_metric;
                if (np->rip6_metric > HOPCNT_INFINITY6)
                        np->rip6_metric = HOPCNT_INFINITY6;

                applyplen(&np->rip6_dest, np->rip6_plen);
                if ((rrt = rtsearch(np)) != NULL) {
                        if (rrt->rrt_t == 0)
                                continue;       /* Intf route has priority */
                        nq = &rrt->rrt_info;
                        if (nq->rip6_metric > np->rip6_metric) {
                                if (rrt->rrt_index == ifcp->ifc_index &&
                                    IN6_ARE_ADDR_EQUAL(&nh, &rrt->rrt_gw)) {
                                        /* Small metric from the same gateway */
                                        nq->rip6_metric = np->rip6_metric;
                                } else {
                                        /* Better route found */
                                        rrt->rrt_index = ifcp->ifc_index;
                                        /* Update routing table */
                                        delroute(nq, &rrt->rrt_gw);
                                        rrt->rrt_gw = nh;
                                        *nq = *np;
                                        addroute(rrt, &nh, ifcp);
                                }
                                rrt->rrt_rflags |= RRTF_CHANGED;
                                rrt->rrt_t = t;
                                need_trigger = 1;
                        } else if (nq->rip6_metric < np->rip6_metric &&
                                   rrt->rrt_index == ifcp->ifc_index &&
                                   IN6_ARE_ADDR_EQUAL(&nh, &rrt->rrt_gw)) {
                                /* Got worse route from same gw */
                                nq->rip6_metric = np->rip6_metric;
                                rrt->rrt_t = t;
                                rrt->rrt_rflags |= RRTF_CHANGED;
                                need_trigger = 1;
                        } else if (nq->rip6_metric == np->rip6_metric &&
                                   np->rip6_metric < HOPCNT_INFINITY6) {
                                if (rrt->rrt_index == ifcp->ifc_index &&
                                   IN6_ARE_ADDR_EQUAL(&nh, &rrt->rrt_gw)) {
                                        /* same metric, same route from same gw */
                                        rrt->rrt_t = t;
                                } else if (rrt->rrt_t < t_half_lifetime) {
                                        /* Better route found */
                                        rrt->rrt_index = ifcp->ifc_index;
                                        /* Update routing table */
                                        delroute(nq, &rrt->rrt_gw);
                                        rrt->rrt_gw = nh;
                                        *nq = *np;
                                        addroute(rrt, &nh, ifcp);
                                        rrt->rrt_rflags |= RRTF_CHANGED;
                                        rrt->rrt_t = t;
                                }
                        }
                        /*
                         * if nq->rip6_metric == HOPCNT_INFINITY6 then
                         * do not update age value.  Do nothing.
                         */
                } else if (np->rip6_metric < HOPCNT_INFINITY6) {
                        /* Got a new valid route */
                        if ((rrt = MALLOC(struct riprt)) == NULL) {
                                fatal("malloc: struct riprt");
                                /*NOTREACHED*/
                        }
                        memset(rrt, 0, sizeof(*rrt));
                        nq = &rrt->rrt_info;

                        rrt->rrt_same = NULL;
                        rrt->rrt_index = ifcp->ifc_index;
                        rrt->rrt_flags = RTF_UP|RTF_GATEWAY;
                        rrt->rrt_gw = nh;
                        *nq = *np;
                        applyplen(&nq->rip6_dest, nq->rip6_plen);
                        if (nq->rip6_plen == sizeof(struct in6_addr) * 8)
                                rrt->rrt_flags |= RTF_HOST;

                        /* Update routing table */
                        addroute(rrt, &nh, ifcp);
                        rrt->rrt_rflags |= RRTF_CHANGED;
                        need_trigger = 1;
                        rrt->rrt_t = t;

                        /* Put the route to the list */
                        TAILQ_INSERT_HEAD(&riprt_head, rrt, rrt_next);
                }
        }
        /* XXX need to care the interval between triggered updates */
        if (need_trigger) {
                if (nextalarm > time(NULL) + RIP_TRIG_INT6_MAX) {
                        TAILQ_FOREACH(ic, &ifc_head, ifc_next) {
                                if (ifcp->ifc_index == ic->ifc_index)
                                        continue;
                                if (ic->ifc_flags & IFF_UP)
                                        ripsend(ic, &ic->ifc_ripsin,
                                                RRTF_CHANGED);
                        }
                }
                /* Reset the flag */
                TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                        rrt->rrt_rflags &= ~RRTF_CHANGED;
                }
        }
}

/*
 * Send all routes request packet to the specified interface.
 */
static void
sendrequest(struct ifc *ifcp)
{
        struct netinfo6 *np;
        int error;

        if (ifcp->ifc_flags & IFF_LOOPBACK)
                return;
        ripbuf->rip6_cmd = RIP6_REQUEST;
        np = ripbuf->rip6_nets;
        memset(np, 0, sizeof(struct netinfo6));
        np->rip6_metric = HOPCNT_INFINITY6;
        tracet(1, "Send rtdump Request to %s (%s)\n",
                ifcp->ifc_name, inet6_n2p(&ifcp->ifc_ripsin.sin6_addr));
        error = sendpacket(&ifcp->ifc_ripsin, RIPSIZE(1));
        if (error == EAFNOSUPPORT) {
                /* Protocol not supported */
                tracet(1, "Could not send rtdump Request to %s (%s): "
                        "set IFF_UP to 0\n",
                        ifcp->ifc_name, inet6_n2p(&ifcp->ifc_ripsin.sin6_addr));
                ifcp->ifc_flags &= ~IFF_UP;     /* As if down for AF_INET6 */
        }
        ripbuf->rip6_cmd = RIP6_RESPONSE;
}

/*
 * Process a RIP6_REQUEST packet.
 */
static void
riprequest(struct ifc *ifcp,
        struct netinfo6 *np,
        int nn,
        struct sockaddr_in6 *sin6)
{
        int i;
        struct riprt *rrt;

        if (!(nn == 1 && IN6_IS_ADDR_UNSPECIFIED(&np->rip6_dest) &&
              np->rip6_plen == 0 && np->rip6_metric == HOPCNT_INFINITY6)) {
                /* Specific response, don't split-horizon */
                trace(1, "\tRIP Request\n");
                for (i = 0; i < nn; i++, np++) {
                        rrt = rtsearch(np);
                        if (rrt)
                                np->rip6_metric = rrt->rrt_info.rip6_metric;
                        else
                                np->rip6_metric = HOPCNT_INFINITY6;
                }
                (void)sendpacket(sin6, RIPSIZE(nn));
                return;
        }
        /* Whole routing table dump */
        trace(1, "\tRIP Request -- whole routing table\n");
        ripsend(ifcp, sin6, RRTF_SENDANYWAY);
}

/*
 * Get information of each interface.
 */
static void
ifconfig(void)
{
        struct ifaddrs *ifap, *ifa;
        struct ifc *ifcp;
        struct ipv6_mreq mreq;
        int s;

        if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
                fatal("socket");
                /*NOTREACHED*/
        }

        if (getifaddrs(&ifap) != 0) {
                fatal("getifaddrs");
                /*NOTREACHED*/
        }

        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                if (ifa->ifa_addr->sa_family != AF_INET6)
                        continue;
                ifcp = ifc_find(ifa->ifa_name);
                /* we are interested in multicast-capable interfaces */
                if ((ifa->ifa_flags & IFF_MULTICAST) == 0)
                        continue;
                if (!ifcp) {
                        /* new interface */
                        if ((ifcp = MALLOC(struct ifc)) == NULL) {
                                fatal("malloc: struct ifc");
                                /*NOTREACHED*/
                        }
                        memset(ifcp, 0, sizeof(*ifcp));

                        ifcp->ifc_index = -1;
                        strlcpy(ifcp->ifc_name, ifa->ifa_name,
                            sizeof(ifcp->ifc_name));
                        TAILQ_INIT(&ifcp->ifc_ifac_head);
                        TAILQ_INIT(&ifcp->ifc_iff_head);
                        ifcp->ifc_flags = ifa->ifa_flags;
                        TAILQ_INSERT_HEAD(&ifc_head, ifcp, ifc_next);
                        trace(1, "newif %s <%s>\n", ifcp->ifc_name,
                                ifflags(ifcp->ifc_flags));
                        if (!strcmp(ifcp->ifc_name, LOOPBACK_IF))
                                loopifcp = ifcp;
                } else {
                        /* update flag, this may be up again */
                        if (ifcp->ifc_flags != ifa->ifa_flags) {
                                trace(1, "%s: <%s> -> ", ifcp->ifc_name,
                                        ifflags(ifcp->ifc_flags));
                                trace(1, "<%s>\n", ifflags(ifa->ifa_flags));
                                ifcp->ifc_cflags |= IFC_CHANGED;
                        }
                        ifcp->ifc_flags = ifa->ifa_flags;
                }
                if (ifconfig1(ifa->ifa_name, ifa->ifa_addr, ifcp, s) < 0) {
                        /* maybe temporary failure */
                        continue;
                }
                if ((ifcp->ifc_flags & (IFF_LOOPBACK | IFF_UP)) == IFF_UP
                 && 0 < ifcp->ifc_index && !ifcp->ifc_joined) {
                        mreq.ipv6mr_multiaddr = ifcp->ifc_ripsin.sin6_addr;
                        mreq.ipv6mr_interface = ifcp->ifc_index;
                        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_JOIN_GROUP,
                            &mreq, sizeof(mreq)) < 0) {
                                fatal("IPV6_JOIN_GROUP");
                                /*NOTREACHED*/
                        }
                        trace(1, "join %s %s\n", ifcp->ifc_name, RIP6_DEST);
                        ifcp->ifc_joined++;
                }
        }
        close(s);
        freeifaddrs(ifap);
}

static int
ifconfig1(const char *name,
        const struct sockaddr *sa,
        struct ifc *ifcp,
        int s)
{
        struct  in6_ifreq ifr;
        const struct sockaddr_in6 *sin6;
        struct  ifac *ifac;
        int     plen;
        char    buf[BUFSIZ];

        sin6 = (const struct sockaddr_in6 *)(const void *)sa;
        if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr) && !lflag)
                return (-1);
        ifr.ifr_addr = *sin6;
        strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        if (ioctl(s, SIOCGIFNETMASK_IN6, (char *)&ifr) < 0) {
                syslog(LOG_INFO, "ioctl: SIOCGIFNETMASK_IN6");
                return (-1);
        }
        plen = sin6mask2len(&ifr.ifr_addr);
        if ((ifac = ifa_match(ifcp, &sin6->sin6_addr, plen)) != NULL) {
                /* same interface found */
                /* need check if something changed */
                /* XXX not yet implemented */
                return (-1);
        }
        /*
         * New address is found
         */
        if ((ifac = MALLOC(struct ifac)) == NULL) {
                fatal("malloc: struct ifac");
                /*NOTREACHED*/
        }
        memset(ifac, 0, sizeof(*ifac));

        ifac->ifac_ifc = ifcp;
        ifac->ifac_addr = sin6->sin6_addr;
        ifac->ifac_plen = plen;
        ifac->ifac_scope_id = sin6->sin6_scope_id;
        if (ifcp->ifc_flags & IFF_POINTOPOINT) {
                ifr.ifr_addr = *sin6;
                if (ioctl(s, SIOCGIFDSTADDR_IN6, (char *)&ifr) < 0) {
                        fatal("ioctl: SIOCGIFDSTADDR_IN6");
                        /*NOTREACHED*/
                }
                ifac->ifac_raddr = ifr.ifr_dstaddr.sin6_addr;
                inet_ntop(AF_INET6, (void *)&ifac->ifac_raddr, buf,
                    sizeof(buf));
                trace(1, "found address %s/%d -- %s\n",
                        inet6_n2p(&ifac->ifac_addr), ifac->ifac_plen, buf);
        } else {
                trace(1, "found address %s/%d\n",
                        inet6_n2p(&ifac->ifac_addr), ifac->ifac_plen);
        }
        if (ifcp->ifc_index < 0 && IN6_IS_ADDR_LINKLOCAL(&ifac->ifac_addr)) {
                ifcp->ifc_mylladdr = ifac->ifac_addr;
                ifcp->ifc_index = ifac->ifac_scope_id;
                memcpy(&ifcp->ifc_ripsin, &ripsin, ripsin.ss_len);
                ifcp->ifc_ripsin.sin6_scope_id = ifcp->ifc_index;
                setindex2ifc(ifcp->ifc_index, ifcp);
                ifcp->ifc_mtu = getifmtu(ifcp->ifc_index);
                if (ifcp->ifc_mtu > RIP6_MAXMTU)
                        ifcp->ifc_mtu = RIP6_MAXMTU;
                if (ioctl(s, SIOCGIFMETRIC, (char *)&ifr) < 0) {
                        fatal("ioctl: SIOCGIFMETRIC");
                        /*NOTREACHED*/
                }
                ifcp->ifc_metric = ifr.ifr_metric;
                trace(1, "\tindex: %d, mtu: %d, metric: %d\n",
                        ifcp->ifc_index, ifcp->ifc_mtu, ifcp->ifc_metric);
        } else
                ifcp->ifc_cflags |= IFC_CHANGED;

        TAILQ_INSERT_HEAD(&ifcp->ifc_ifac_head, ifac, ifac_next);

        return 0;
}

static void
ifremove(int ifindex)
{
        struct ifc *ifcp;
        struct riprt *rrt;

        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                if (ifcp->ifc_index == ifindex)
                        break;
        }
        if (ifcp == NULL)
                return;

        tracet(1, "ifremove: %s is departed.\n", ifcp->ifc_name);
        TAILQ_REMOVE(&ifc_head, ifcp, ifc_next);

        TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                if (rrt->rrt_index == ifcp->ifc_index &&
                    rrt->rrt_rflags & RRTF_AGGREGATE)
                        delroute(&rrt->rrt_info, &rrt->rrt_gw);
        }
        free(ifcp);
}

/*
 * Receive and process routing messages.
 * Update interface information as necessary.
 */
static void
rtrecv(void)
{
        char buf[BUFSIZ];
        char *p, *q = NULL;
        struct rt_msghdr *rtm;
        struct ifa_msghdr *ifam;
        struct if_msghdr *ifm;
        struct if_announcemsghdr *ifan;
        int len;
        struct ifc *ifcp, *ic;
        int iface = 0, rtable = 0;
        struct sockaddr_in6 *rta[RTAX_MAX];
        struct sockaddr_in6 mask;
        int i, addrs = 0;
        struct riprt *rrt;

        if ((len = read(rtsock, buf, sizeof(buf))) < 0) {
                perror("read from rtsock");
                exit(1);
        }
        if (len == 0)
                return;
#if 0
        if (len < sizeof(*rtm)) {
                trace(1, "short read from rtsock: %d (should be > %lu)\n",
                        len, (u_long)sizeof(*rtm));
                return;
        }
#endif
        if (dflag >= 2) {
                fprintf(stderr, "rtmsg:\n");
                for (i = 0; i < len; i++) {
                        fprintf(stderr, "%02x ", buf[i] & 0xff);
                        if (i % 16 == 15) fprintf(stderr, "\n");
                }
                fprintf(stderr, "\n");
        }

        for (p = buf; p - buf < len; p +=
            ((struct rt_msghdr *)(void *)p)->rtm_msglen) {
                if (((struct rt_msghdr *)(void *)p)->rtm_version != RTM_VERSION)
                        continue;

                /* safety against bogus message */
                if (((struct rt_msghdr *)(void *)p)->rtm_msglen <= 0) {
                        trace(1, "bogus rtmsg: length=%d\n",
                                ((struct rt_msghdr *)(void *)p)->rtm_msglen);
                        break;
                }
                rtm = NULL;
                ifam = NULL;
                ifm = NULL;
                switch (((struct rt_msghdr *)(void *)p)->rtm_type) {
                case RTM_NEWADDR:
                case RTM_DELADDR:
                        ifam = (struct ifa_msghdr *)(void *)p;
                        addrs = ifam->ifam_addrs;
                        q = (char *)(ifam + 1);
                        break;
                case RTM_IFINFO:
                        ifm = (struct if_msghdr *)(void *)p;
                        addrs = ifm->ifm_addrs;
                        q = (char *)(ifm + 1);
                        break;
                case RTM_IFANNOUNCE:
                        ifan = (struct if_announcemsghdr *)(void *)p;
                        switch (ifan->ifan_what) {
                        case IFAN_ARRIVAL:
                                iface++;
                                break;
                        case IFAN_DEPARTURE:
                                ifremove(ifan->ifan_index);
                                iface++;
                                break;
                        }
                        break;
                default:
                        rtm = (struct rt_msghdr *)(void *)p;
                        if (rtm->rtm_version != RTM_VERSION) {
                                trace(1, "unexpected rtmsg version %d "
                                        "(should be %d)\n",
                                        rtm->rtm_version, RTM_VERSION);
                                continue;
                        }
                        /*
                         * Only messages that use the struct rt_msghdr
                         * format are allowed beyond this point.
                         */
                        if (rtm->rtm_type > RTM_RESOLVE) {
                                trace(1, "rtmsg type %d ignored\n",
                                        rtm->rtm_type);
                                continue;
                        }
                        addrs = rtm->rtm_addrs;
                        q = (char *)(rtm + 1);
                        if (rtm->rtm_pid == pid) {
#if 0
                                trace(1, "rtmsg looped back to me, ignored\n");
#endif
                                continue;
                        }
                        break;
                }
                memset(&rta, 0, sizeof(rta));
                for (i = 0; i < RTAX_MAX; i++) {
                        if (addrs & (1 << i)) {
                                rta[i] = (struct sockaddr_in6 *)(void *)q;
                                q += ROUNDUP(rta[i]->sin6_len);
                        }
                }

                trace(1, "rtsock: %s (addrs=%x)\n",
                        rttypes((struct rt_msghdr *)(void *)p), addrs);
                if (dflag >= 2) {
                        for (i = 0;
                             i < ((struct rt_msghdr *)(void *)p)->rtm_msglen;
                             i++) {
                                fprintf(stderr, "%02x ", p[i] & 0xff);
                                if (i % 16 == 15) fprintf(stderr, "\n");
                        }
                        fprintf(stderr, "\n");
                }

                /*
                 * Easy ones first.
                 *
                 * We may be able to optimize by using ifm->ifm_index or
                 * ifam->ifam_index.  For simplicity we don't do that here.
                 */
                switch (((struct rt_msghdr *)(void *)p)->rtm_type) {
                case RTM_NEWADDR:
                case RTM_IFINFO:
                        iface++;
                        continue;
                case RTM_ADD:
                        rtable++;
                        continue;
                case RTM_LOSING:
                case RTM_MISS:
                case RTM_GET:
                case RTM_LOCK:
                        /* nothing to be done here */
                        trace(1, "\tnothing to be done, ignored\n");
                        continue;
                }

#if 0
                if (rta[RTAX_DST] == NULL) {
                        trace(1, "\tno destination, ignored\n");
                        continue;
                }
                if (rta[RTAX_DST]->sin6_family != AF_INET6) {
                        trace(1, "\taf mismatch, ignored\n");
                        continue;
                }
                if (IN6_IS_ADDR_LINKLOCAL(&rta[RTAX_DST]->sin6_addr)) {
                        trace(1, "\tlinklocal destination, ignored\n");
                        continue;
                }
                if (IN6_ARE_ADDR_EQUAL(&rta[RTAX_DST]->sin6_addr, &in6addr_loopback)) {
                        trace(1, "\tloopback destination, ignored\n");
                        continue;               /* Loopback */
                }
                if (IN6_IS_ADDR_MULTICAST(&rta[RTAX_DST]->sin6_addr)) {
                        trace(1, "\tmulticast destination, ignored\n");
                        continue;
                }
#endif

                /* hard ones */
                switch (((struct rt_msghdr *)(void *)p)->rtm_type) {
                case RTM_NEWADDR:
                case RTM_IFINFO:
                case RTM_ADD:
                case RTM_LOSING:
                case RTM_MISS:
                case RTM_GET:
                case RTM_LOCK:
                        /* should already be handled */
                        fatal("rtrecv: never reach here");
                        /*NOTREACHED*/
                case RTM_DELETE:
                        if (!rta[RTAX_DST] || !rta[RTAX_GATEWAY]) {
                                trace(1, "\tsome of dst/gw/netamsk are "
                                    "unavailable, ignored\n");
                                break;
                        }
                        if ((rtm->rtm_flags & RTF_HOST) != 0) {
                                mask.sin6_len = sizeof(mask);
                                memset(&mask.sin6_addr, 0xff,
                                    sizeof(mask.sin6_addr));
                                rta[RTAX_NETMASK] = &mask;
                        } else if (!rta[RTAX_NETMASK]) {
                                trace(1, "\tsome of dst/gw/netamsk are "
                                    "unavailable, ignored\n");
                                break;
                        }
                        if (rt_del(rta[RTAX_DST], rta[RTAX_GATEWAY],
                            rta[RTAX_NETMASK]) == 0) {
                                rtable++;       /*just to be sure*/
                        }
                        break;
                case RTM_CHANGE:
                case RTM_REDIRECT:
                        trace(1, "\tnot supported yet, ignored\n");
                        break;
                case RTM_DELADDR:
                        if (!rta[RTAX_NETMASK] || !rta[RTAX_IFA]) {
                                trace(1, "\tno netmask or ifa given, ignored\n");
                                break;
                        }
                        if (ifam->ifam_index < nindex2ifc)
                                ifcp = index2ifc[ifam->ifam_index];
                        else
                                ifcp = NULL;
                        if (!ifcp) {
                                trace(1, "\tinvalid ifam_index %d, ignored\n",
                                        ifam->ifam_index);
                                break;
                        }
                        if (!rt_deladdr(ifcp, rta[RTAX_IFA], rta[RTAX_NETMASK]))
                                iface++;
                        break;
                }

        }

        if (iface) {
                trace(1, "rtsock: reconfigure interfaces, refresh interface routes\n");
                ifconfig();
                TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                        if (ifcp->ifc_cflags & IFC_CHANGED) {
                                if (ifrt(ifcp, 1)) {
                                        TAILQ_FOREACH(ic, &ifc_head, ifc_next) {
                                                if (ifcp->ifc_index == ic->ifc_index)
                                                        continue;
                                                if (ic->ifc_flags & IFF_UP)
                                                        ripsend(ic, &ic->ifc_ripsin,
                                                        RRTF_CHANGED);
                                        }
                                        /* Reset the flag */
                                        TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                                                rrt->rrt_rflags &= ~RRTF_CHANGED;
                                        }
                                }
                                ifcp->ifc_cflags &= ~IFC_CHANGED;
                        }
                }
        }
        if (rtable) {
                trace(1, "rtsock: read routing table again\n");
                krtread(1);
        }
}

/*
 * remove specified route from the internal routing table.
 */
static int
rt_del(const struct sockaddr_in6 *sdst,
        const struct sockaddr_in6 *sgw,
        const struct sockaddr_in6 *smask)
{
        const struct in6_addr *dst = NULL;
        const struct in6_addr *gw = NULL;
        int prefix;
        struct netinfo6 ni6;
        struct riprt *rrt = NULL;
        time_t t_lifetime;

        if (sdst->sin6_family != AF_INET6) {
                trace(1, "\tother AF, ignored\n");
                return -1;
        }
        if (IN6_IS_ADDR_LINKLOCAL(&sdst->sin6_addr)
         || IN6_ARE_ADDR_EQUAL(&sdst->sin6_addr, &in6addr_loopback)
         || IN6_IS_ADDR_MULTICAST(&sdst->sin6_addr)) {
                trace(1, "\taddress %s not interesting, ignored\n",
                        inet6_n2p(&sdst->sin6_addr));
                return -1;
        }
        dst = &sdst->sin6_addr;
        if (sgw->sin6_family == AF_INET6) {
                /* easy case */
                gw = &sgw->sin6_addr;
                prefix = sin6mask2len(smask);
        } else if (sgw->sin6_family == AF_LINK) {
                /*
                 * Interface route... a hard case.  We need to get the prefix
                 * length from the kernel, but we now are parsing rtmsg.
                 * We'll purge matching routes from my list, then get the
                 * fresh list.
                 */
                struct riprt *longest;
                trace(1, "\t%s is an interface route, guessing prefixlen\n",
                        inet6_n2p(dst));
                longest = NULL;
                TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                        if (IN6_ARE_ADDR_EQUAL(&rrt->rrt_info.rip6_dest,
                                        &sdst->sin6_addr)
                         && IN6_IS_ADDR_LOOPBACK(&rrt->rrt_gw)) {
                                if (!longest
                                 || longest->rrt_info.rip6_plen <
                                                 rrt->rrt_info.rip6_plen) {
                                        longest = rrt;
                                }
                        }
                }
                rrt = longest;
                if (!rrt) {
                        trace(1, "\tno matching interface route found\n");
                        return -1;
                }
                gw = &in6addr_loopback;
                prefix = rrt->rrt_info.rip6_plen;
        } else {
                trace(1, "\tunsupported af: (gw=%d)\n", sgw->sin6_family);
                return -1;
        }

        trace(1, "\tdeleting %s/%d ", inet6_n2p(dst), prefix);
        trace(1, "gw %s\n", inet6_n2p(gw));
        t_lifetime = time(NULL) - RIP_LIFETIME;
        /* age route for interface address */
        memset(&ni6, 0, sizeof(ni6));
        ni6.rip6_dest = *dst;
        ni6.rip6_plen = prefix;
        applyplen(&ni6.rip6_dest, ni6.rip6_plen);       /*to be sure*/
        trace(1, "\tfind route %s/%d\n", inet6_n2p(&ni6.rip6_dest),
                ni6.rip6_plen);
        if (!rrt && (rrt = rtsearch(&ni6)) == NULL) {
                trace(1, "\tno route found\n");
                return -1;
        }
#if 0
        if ((rrt->rrt_flags & RTF_STATIC) == 0) {
                trace(1, "\tyou can delete static routes only\n");
        } else
#endif
        if (!IN6_ARE_ADDR_EQUAL(&rrt->rrt_gw, gw)) {
                trace(1, "\tgw mismatch: %s <-> ",
                        inet6_n2p(&rrt->rrt_gw));
                trace(1, "%s\n", inet6_n2p(gw));
        } else {
                trace(1, "\troute found, age it\n");
                if (rrt->rrt_t == 0 || rrt->rrt_t > t_lifetime) {
                        rrt->rrt_t = t_lifetime;
                        rrt->rrt_info.rip6_metric = HOPCNT_INFINITY6;
                }
        }
        return 0;
}

/*
 * remove specified address from internal interface/routing table.
 */
static int
rt_deladdr(struct ifc *ifcp,
        const struct sockaddr_in6 *sifa,
        const struct sockaddr_in6 *smask)
{
        const struct in6_addr *addr = NULL;
        int prefix;
        struct ifac *ifac = NULL;
        struct netinfo6 ni6;
        struct riprt *rrt = NULL;
        time_t t_lifetime;
        int updated = 0;

        if (sifa->sin6_family != AF_INET6) {
                trace(1, "\tother AF, ignored\n");
                return -1;
        }
        addr = &sifa->sin6_addr;
        prefix = sin6mask2len(smask);

        trace(1, "\tdeleting %s/%d from %s\n",
                inet6_n2p(addr), prefix, ifcp->ifc_name);
        ifac = ifa_match(ifcp, addr, prefix);
        if (!ifac) {
                trace(1, "\tno matching ifa found for %s/%d on %s\n",
                        inet6_n2p(addr), prefix, ifcp->ifc_name);
                return -1;
        }
        if (ifac->ifac_ifc != ifcp) {
                trace(1, "\taddress table corrupt: back pointer does not match "
                        "(%s != %s)\n",
                        ifcp->ifc_name, ifac->ifac_ifc->ifc_name);
                return -1;
        }
        TAILQ_REMOVE(&ifcp->ifc_ifac_head, ifac, ifac_next);
        t_lifetime = time(NULL) - RIP_LIFETIME;
        /* age route for interface address */
        memset(&ni6, 0, sizeof(ni6));
        ni6.rip6_dest = ifac->ifac_addr;
        ni6.rip6_plen = ifac->ifac_plen;
        applyplen(&ni6.rip6_dest, ni6.rip6_plen);
        trace(1, "\tfind interface route %s/%d on %d\n",
                inet6_n2p(&ni6.rip6_dest), ni6.rip6_plen, ifcp->ifc_index);
        if ((rrt = rtsearch(&ni6)) != NULL) {
                struct in6_addr none;
                memset(&none, 0, sizeof(none));
                if (rrt->rrt_index == ifcp->ifc_index &&
                    (IN6_ARE_ADDR_EQUAL(&rrt->rrt_gw, &none) ||
                     IN6_IS_ADDR_LOOPBACK(&rrt->rrt_gw))) {
                        trace(1, "\troute found, age it\n");
                        if (rrt->rrt_t == 0 || rrt->rrt_t > t_lifetime) {
                                rrt->rrt_t = t_lifetime;
                                rrt->rrt_info.rip6_metric = HOPCNT_INFINITY6;
                        }
                        updated++;
                } else {
                        trace(1, "\tnon-interface route found: %s/%d on %d\n",
                                inet6_n2p(&rrt->rrt_info.rip6_dest),
                                rrt->rrt_info.rip6_plen,
                                rrt->rrt_index);
                }
        } else
                trace(1, "\tno interface route found\n");
        /* age route for p2p destination */
        if (ifcp->ifc_flags & IFF_POINTOPOINT) {
                memset(&ni6, 0, sizeof(ni6));
                ni6.rip6_dest = ifac->ifac_raddr;
                ni6.rip6_plen = 128;
                applyplen(&ni6.rip6_dest, ni6.rip6_plen);       /*to be sure*/
                trace(1, "\tfind p2p route %s/%d on %d\n",
                        inet6_n2p(&ni6.rip6_dest), ni6.rip6_plen,
                        ifcp->ifc_index);
                if ((rrt = rtsearch(&ni6)) != NULL) {
                        if (rrt->rrt_index == ifcp->ifc_index &&
                            IN6_ARE_ADDR_EQUAL(&rrt->rrt_gw,
                            &ifac->ifac_addr)) {
                                trace(1, "\troute found, age it\n");
                                if (rrt->rrt_t == 0 || rrt->rrt_t > t_lifetime) {
                                        rrt->rrt_t = t_lifetime;
                                        rrt->rrt_info.rip6_metric =
                                            HOPCNT_INFINITY6;
                                        updated++;
                                }
                        } else {
                                trace(1, "\tnon-p2p route found: %s/%d on %d\n",
                                        inet6_n2p(&rrt->rrt_info.rip6_dest),
                                        rrt->rrt_info.rip6_plen,
                                        rrt->rrt_index);
                        }
                } else
                        trace(1, "\tno p2p route found\n");
        }
        free(ifac);

        return ((updated) ? 0 : -1);
}

/*
 * Get each interface address and put those interface routes to the route
 * list.
 */
static int
ifrt(struct ifc *ifcp, int again)
{
        struct ifac *ifac;
        struct riprt *rrt = NULL, *search_rrt, *loop_rrt;
        struct netinfo6 *np;
        time_t t_lifetime;
        int need_trigger = 0;

#if 0
        if (ifcp->ifc_flags & IFF_LOOPBACK)
                return 0;                       /* ignore loopback */
#endif

        if (ifcp->ifc_flags & IFF_POINTOPOINT) {
                ifrt_p2p(ifcp, again);
                return 0;
        }

        TAILQ_FOREACH(ifac, &ifcp->ifc_ifac_head, ifac_next) {
                if (IN6_IS_ADDR_LINKLOCAL(&ifac->ifac_addr)) {
#if 0
                        trace(1, "route: %s on %s: "
                            "skip linklocal interface address\n",
                            inet6_n2p(&ifac->ifac_addr), ifcp->ifc_name);
#endif
                        continue;
                }
                if (IN6_IS_ADDR_UNSPECIFIED(&ifac->ifac_addr)) {
#if 0
                        trace(1, "route: %s: skip unspec interface address\n",
                            ifcp->ifc_name);
#endif
                        continue;
                }
                if (IN6_IS_ADDR_LOOPBACK(&ifac->ifac_addr)) {
#if 0
                        trace(1, "route: %s: skip loopback address\n",
                            ifcp->ifc_name);
#endif
                        continue;
                }
                if (ifcp->ifc_flags & IFF_UP) {
                        if ((rrt = MALLOC(struct riprt)) == NULL)
                                fatal("malloc: struct riprt");
                        memset(rrt, 0, sizeof(*rrt));
                        rrt->rrt_same = NULL;
                        rrt->rrt_index = ifcp->ifc_index;
                        rrt->rrt_t = 0; /* don't age */
                        rrt->rrt_info.rip6_dest = ifac->ifac_addr;
                        rrt->rrt_info.rip6_tag = htons(routetag & 0xffff);
                        rrt->rrt_info.rip6_metric = 1 + ifcp->ifc_metric;
                        rrt->rrt_info.rip6_plen = ifac->ifac_plen;
                        rrt->rrt_flags = RTF_HOST;
                        rrt->rrt_rflags |= RRTF_CHANGED;
                        applyplen(&rrt->rrt_info.rip6_dest, ifac->ifac_plen);
                        memset(&rrt->rrt_gw, 0, sizeof(struct in6_addr));
                        rrt->rrt_gw = ifac->ifac_addr;
                        np = &rrt->rrt_info;
                        search_rrt = rtsearch(np);
                        if (search_rrt != NULL) {
                                if (search_rrt->rrt_info.rip6_metric <=
                                    rrt->rrt_info.rip6_metric) {
                                        /* Already have better route */
                                        if (!again) {
                                                trace(1, "route: %s/%d: "
                                                    "already registered (%s)\n",
                                                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                                                    ifcp->ifc_name);
                                        }
                                        goto next;
                                }

                                TAILQ_REMOVE(&riprt_head, search_rrt, rrt_next);
                                delroute(&search_rrt->rrt_info,
                                    &search_rrt->rrt_gw);
                                free(search_rrt);
                        }
                        /* Attach the route to the list */
                        trace(1, "route: %s/%d: register route (%s)\n",
                            inet6_n2p(&np->rip6_dest), np->rip6_plen,
                            ifcp->ifc_name);
                        TAILQ_INSERT_HEAD(&riprt_head, rrt, rrt_next);
                        addroute(rrt, &rrt->rrt_gw, ifcp);
                        rrt = NULL;
                        sendrequest(ifcp);
                        ripsend(ifcp, &ifcp->ifc_ripsin, 0);
                        need_trigger = 1;
                } else {
                        TAILQ_FOREACH(loop_rrt, &riprt_head, rrt_next) {
                                if (loop_rrt->rrt_index == ifcp->ifc_index) {
                                        t_lifetime = time(NULL) - RIP_LIFETIME;
                                        if (loop_rrt->rrt_t == 0 || loop_rrt->rrt_t > t_lifetime) {
                                                loop_rrt->rrt_t = t_lifetime;
                                                loop_rrt->rrt_info.rip6_metric = HOPCNT_INFINITY6;
                                                loop_rrt->rrt_rflags |= RRTF_CHANGED;
                                                need_trigger = 1;
                                        }
                                }
                        }
                }
        next:
                if (rrt)
                        free(rrt);
        }
        return need_trigger;
}

/*
 * there are couple of p2p interface routing models.  "behavior" lets
 * you pick one.  it looks that gated behavior fits best with BSDs,
 * since BSD kernels do not look at prefix length on p2p interfaces.
 */
static void
ifrt_p2p(struct ifc *ifcp, int again)
{
        struct ifac *ifac;
        struct riprt *rrt, *orrt;
        struct netinfo6 *np;
        struct in6_addr addr, dest;
        int advert, ignore, i;
#define P2PADVERT_NETWORK       1
#define P2PADVERT_ADDR          2
#define P2PADVERT_DEST          4
#define P2PADVERT_MAX           4
        const enum { CISCO, GATED, ROUTE6D } behavior = GATED;
        const char *category = "";
        const char *noadv;

        TAILQ_FOREACH(ifac, &ifcp->ifc_ifac_head, ifac_next) {
                addr = ifac->ifac_addr;
                dest = ifac->ifac_raddr;
                applyplen(&addr, ifac->ifac_plen);
                applyplen(&dest, ifac->ifac_plen);
                advert = ignore = 0;
                switch (behavior) {
                case CISCO:
                        /*
                         * honor addr/plen, just like normal shared medium
                         * interface.  this may cause trouble if you reuse
                         * addr/plen on other interfaces.
                         *
                         * advertise addr/plen.
                         */
                        advert |= P2PADVERT_NETWORK;
                        break;
                case GATED:
                        /*
                         * prefixlen on p2p interface is meaningless.
                         * advertise addr/128 and dest/128.
                         *
                         * do not install network route to route6d routing
                         * table (if we do, it would prevent route installation
                         * for other p2p interface that shares addr/plen).
                         *
                         * XXX what should we do if dest is ::?  it will not
                         * get announced anyways (see following filter),
                         * but we need to think.
                         */
                        advert |= P2PADVERT_ADDR;
                        advert |= P2PADVERT_DEST;
                        ignore |= P2PADVERT_NETWORK;
                        break;
                case ROUTE6D:
                        /*
                         * just for testing.  actually the code is redundant
                         * given the current p2p interface address assignment
                         * rule for kame kernel.
                         *
                         * intent:
                         *      A/n -> announce A/n
                         *      A B/n, A and B share prefix -> A/n (= B/n)
                         *      A B/n, do not share prefix -> A/128 and B/128
                         * actually, A/64 and A B/128 are the only cases
                         * permitted by the kernel:
                         *      A/64 -> A/64
                         *      A B/128 -> A/128 and B/128
                         */
                        if (!IN6_IS_ADDR_UNSPECIFIED(&ifac->ifac_raddr)) {
                                if (IN6_ARE_ADDR_EQUAL(&addr, &dest))
                                        advert |= P2PADVERT_NETWORK;
                                else {
                                        advert |= P2PADVERT_ADDR;
                                        advert |= P2PADVERT_DEST;
                                        ignore |= P2PADVERT_NETWORK;
                                }
                        } else
                                advert |= P2PADVERT_NETWORK;
                        break;
                }

                for (i = 1; i <= P2PADVERT_MAX; i *= 2) {
                        if ((ignore & i) != 0)
                                continue;
                        if ((rrt = MALLOC(struct riprt)) == NULL) {
                                fatal("malloc: struct riprt");
                                /*NOTREACHED*/
                        }
                        memset(rrt, 0, sizeof(*rrt));
                        rrt->rrt_same = NULL;
                        rrt->rrt_index = ifcp->ifc_index;
                        rrt->rrt_t = 0; /* don't age */
                        switch (i) {
                        case P2PADVERT_NETWORK:
                                rrt->rrt_info.rip6_dest = ifac->ifac_addr;
                                rrt->rrt_info.rip6_plen = ifac->ifac_plen;
                                applyplen(&rrt->rrt_info.rip6_dest,
                                    ifac->ifac_plen);
                                category = "network";
                                break;
                        case P2PADVERT_ADDR:
                                rrt->rrt_info.rip6_dest = ifac->ifac_addr;
                                rrt->rrt_info.rip6_plen = 128;
                                rrt->rrt_gw = in6addr_loopback;
                                category = "addr";
                                break;
                        case P2PADVERT_DEST:
                                rrt->rrt_info.rip6_dest = ifac->ifac_raddr;
                                rrt->rrt_info.rip6_plen = 128;
                                rrt->rrt_gw = ifac->ifac_addr;
                                category = "dest";
                                break;
                        }
                        if (IN6_IS_ADDR_UNSPECIFIED(&rrt->rrt_info.rip6_dest) ||
                            IN6_IS_ADDR_LINKLOCAL(&rrt->rrt_info.rip6_dest)) {
#if 0
                                trace(1, "route: %s: skip unspec/linklocal "
                                    "(%s on %s)\n", category, ifcp->ifc_name);
#endif
                                free(rrt);
                                continue;
                        }
                        if ((advert & i) == 0) {
                                rrt->rrt_rflags |= RRTF_NOADVERTISE;
                                noadv = ", NO-ADV";
                        } else
                                noadv = "";
                        rrt->rrt_info.rip6_tag = htons(routetag & 0xffff);
                        rrt->rrt_info.rip6_metric = 1 + ifcp->ifc_metric;
                        np = &rrt->rrt_info;
                        orrt = rtsearch(np);
                        if (!orrt) {
                                /* Attach the route to the list */
                                trace(1, "route: %s/%d: register route "
                                    "(%s on %s%s)\n",
                                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                                    category, ifcp->ifc_name, noadv);
                                TAILQ_INSERT_HEAD(&riprt_head, rrt, rrt_next);
                        } else if (rrt->rrt_index != orrt->rrt_index ||
                            rrt->rrt_info.rip6_metric != orrt->rrt_info.rip6_metric) {
                                /* replace route */
                                TAILQ_INSERT_BEFORE(orrt, rrt, rrt_next);
                                TAILQ_REMOVE(&riprt_head, orrt, rrt_next);
                                free(orrt);

                                trace(1, "route: %s/%d: update (%s on %s%s)\n",
                                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                                    category, ifcp->ifc_name, noadv);
                        } else {
                                /* Already found */
                                if (!again) {
                                        trace(1, "route: %s/%d: "
                                            "already registered (%s on %s%s)\n",
                                            inet6_n2p(&np->rip6_dest),
                                            np->rip6_plen, category,
                                            ifcp->ifc_name, noadv);
                                }
                                free(rrt);
                        }
                }
        }
#undef P2PADVERT_NETWORK
#undef P2PADVERT_ADDR
#undef P2PADVERT_DEST
#undef P2PADVERT_MAX
}

static int
getifmtu(int ifindex)
{
        int     mib[6];
        char    *buf;
        size_t  msize;
        struct  if_msghdr *ifm;
        int     mtu;

        mib[0] = CTL_NET;
        mib[1] = PF_ROUTE;
        mib[2] = 0;
        mib[3] = AF_INET6;
        mib[4] = NET_RT_IFLIST;
        mib[5] = ifindex;
        if (sysctl(mib, nitems(mib), NULL, &msize, NULL, 0) < 0) {
                fatal("sysctl estimate NET_RT_IFLIST");
                /*NOTREACHED*/
        }
        if ((buf = malloc(msize)) == NULL) {
                fatal("malloc");
                /*NOTREACHED*/
        }
        if (sysctl(mib, nitems(mib), buf, &msize, NULL, 0) < 0) {
                fatal("sysctl NET_RT_IFLIST");
                /*NOTREACHED*/
        }
        ifm = (struct if_msghdr *)(void *)buf;
        mtu = ifm->ifm_data.ifi_mtu;
        if (ifindex != ifm->ifm_index) {
                fatal("ifindex does not match with ifm_index");
                /*NOTREACHED*/
        }
        free(buf);
        return mtu;
}

static const char *
rttypes(struct rt_msghdr *rtm)
{
#define RTTYPE(s, f) \
do { \
        if (rtm->rtm_type == (f)) \
                return (s); \
} while (0)
        RTTYPE("ADD", RTM_ADD);
        RTTYPE("DELETE", RTM_DELETE);
        RTTYPE("CHANGE", RTM_CHANGE);
        RTTYPE("GET", RTM_GET);
        RTTYPE("LOSING", RTM_LOSING);
        RTTYPE("REDIRECT", RTM_REDIRECT);
        RTTYPE("MISS", RTM_MISS);
        RTTYPE("LOCK", RTM_LOCK);
        RTTYPE("NEWADDR", RTM_NEWADDR);
        RTTYPE("DELADDR", RTM_DELADDR);
        RTTYPE("IFINFO", RTM_IFINFO);
#ifdef RTM_OIFINFO
        RTTYPE("OIFINFO", RTM_OIFINFO);
#endif
#ifdef RTM_IFANNOUNCE
        RTTYPE("IFANNOUNCE", RTM_IFANNOUNCE);
#endif
#ifdef RTM_NEWMADDR
        RTTYPE("NEWMADDR", RTM_NEWMADDR);
#endif
#ifdef RTM_DELMADDR
        RTTYPE("DELMADDR", RTM_DELMADDR);
#endif
#undef RTTYPE
        return NULL;
}

static const char *
rtflags(struct rt_msghdr *rtm)
{
        static char buf[BUFSIZ];

        /*
         * letter conflict should be okay.  painful when *BSD diverges...
         */
        strlcpy(buf, "", sizeof(buf));
#define RTFLAG(s, f) \
do { \
        if (rtm->rtm_flags & (f)) \
                strlcat(buf, (s), sizeof(buf)); \
} while (0)
        RTFLAG("U", RTF_UP);
        RTFLAG("G", RTF_GATEWAY);
        RTFLAG("H", RTF_HOST);
        RTFLAG("R", RTF_REJECT);
        RTFLAG("D", RTF_DYNAMIC);
        RTFLAG("M", RTF_MODIFIED);
        RTFLAG("d", RTF_DONE);
#ifdef  RTF_MASK
        RTFLAG("m", RTF_MASK);
#endif
#ifdef RTF_CLONED
        RTFLAG("c", RTF_CLONED);
#endif
        RTFLAG("X", RTF_XRESOLVE);
#ifdef RTF_LLINFO
        RTFLAG("L", RTF_LLINFO);
#endif
        RTFLAG("S", RTF_STATIC);
        RTFLAG("B", RTF_BLACKHOLE);
#ifdef RTF_PROTO3
        RTFLAG("3", RTF_PROTO3);
#endif
        RTFLAG("2", RTF_PROTO2);
        RTFLAG("1", RTF_PROTO1);
#ifdef RTF_BROADCAST
        RTFLAG("b", RTF_BROADCAST);
#endif
#ifdef RTF_DEFAULT
        RTFLAG("d", RTF_DEFAULT);
#endif
#ifdef RTF_ISAROUTER
        RTFLAG("r", RTF_ISAROUTER);
#endif
#ifdef RTF_TUNNEL
        RTFLAG("T", RTF_TUNNEL);
#endif
#ifdef RTF_AUTH
        RTFLAG("A", RTF_AUTH);
#endif
#ifdef RTF_CRYPT
        RTFLAG("E", RTF_CRYPT);
#endif
#undef RTFLAG
        return buf;
}

static const char *
ifflags(int flags)
{
        static char buf[BUFSIZ];

        strlcpy(buf, "", sizeof(buf));
#define IFFLAG(s, f) \
do { \
        if (flags & (f)) { \
                if (buf[0]) \
                        strlcat(buf, ",", sizeof(buf)); \
                strlcat(buf, (s), sizeof(buf)); \
        } \
} while (0)
        IFFLAG("UP", IFF_UP);
        IFFLAG("BROADCAST", IFF_BROADCAST);
        IFFLAG("DEBUG", IFF_DEBUG);
        IFFLAG("LOOPBACK", IFF_LOOPBACK);
        IFFLAG("POINTOPOINT", IFF_POINTOPOINT);
#ifdef IFF_NOTRAILERS
        IFFLAG("NOTRAILERS", IFF_NOTRAILERS);
#endif
        IFFLAG("RUNNING", IFF_RUNNING);
        IFFLAG("NOARP", IFF_NOARP);
        IFFLAG("PROMISC", IFF_PROMISC);
        IFFLAG("ALLMULTI", IFF_ALLMULTI);
        IFFLAG("OACTIVE", IFF_OACTIVE);
        IFFLAG("SIMPLEX", IFF_SIMPLEX);
        IFFLAG("LINK0", IFF_LINK0);
        IFFLAG("LINK1", IFF_LINK1);
        IFFLAG("LINK2", IFF_LINK2);
        IFFLAG("MULTICAST", IFF_MULTICAST);
#undef IFFLAG
        return buf;
}

static void
krtread(int again)
{
        int mib[6];
        size_t msize;
        char *buf, *p, *lim;
        struct rt_msghdr *rtm;
        int retry;
        const char *errmsg;

        retry = 0;
        buf = NULL;
        mib[0] = CTL_NET;
        mib[1] = PF_ROUTE;
        mib[2] = 0;
        mib[3] = AF_INET6;      /* Address family */
        mib[4] = NET_RT_DUMP;   /* Dump the kernel routing table */
        mib[5] = 0;             /* No flags */
        do {
                if (retry)
                        sleep(1);
                retry++;
                errmsg = NULL;
                if (buf) {
                        free(buf);
                        buf = NULL;
                }
                if (sysctl(mib, nitems(mib), NULL, &msize, NULL, 0) < 0) {
                        errmsg = "sysctl estimate";
                        continue;
                }
                if ((buf = malloc(msize)) == NULL) {
                        errmsg = "malloc";
                        continue;
                }
                if (sysctl(mib, nitems(mib), buf, &msize, NULL, 0) < 0) {
                        errmsg = "sysctl NET_RT_DUMP";
                        continue;
                }
        } while (retry < RT_DUMP_MAXRETRY && errmsg != NULL);
        if (errmsg) {
                fatal("%s (with %d retries, msize=%lu)", errmsg, retry,
                    (u_long)msize);
                /*NOTREACHED*/
        } else if (1 < retry)
                syslog(LOG_INFO, "NET_RT_DUMP %d retires", retry);

        lim = buf + msize;
        for (p = buf; p < lim; p += rtm->rtm_msglen) {
                rtm = (struct rt_msghdr *)(void *)p;
                rt_entry(rtm, again);
        }
        free(buf);
}

static void
rt_entry(struct rt_msghdr *rtm, int again)
{
        struct  sockaddr_in6 *sin6_dst, *sin6_gw, *sin6_mask;
        struct  sockaddr_in6 *sin6_genmask, *sin6_ifp;
        char    *rtmp, *ifname = NULL;
        struct  riprt *rrt, *orrt;
        struct  netinfo6 *np;
        int ifindex;

        sin6_dst = sin6_gw = sin6_mask = sin6_genmask = sin6_ifp = 0;
        if ((rtm->rtm_flags & RTF_UP) == 0 || rtm->rtm_flags &
                (RTF_XRESOLVE|RTF_BLACKHOLE)) {
                return;         /* not interested in the link route */
        }
        /* do not look at cloned routes */
#ifdef RTF_WASCLONED
        if (rtm->rtm_flags & RTF_WASCLONED)
                return;
#endif
#ifdef RTF_CLONED
        if (rtm->rtm_flags & RTF_CLONED)
                return;
#endif
        /* XXX: Ignore connected routes. */
        if (!(rtm->rtm_flags & (RTF_GATEWAY|RTF_HOST|RTF_STATIC)))
                return;
        /*
         * do not look at dynamic routes.
         * netbsd/openbsd cloned routes have UGHD.
         */
        if (rtm->rtm_flags & RTF_DYNAMIC)
                return;
        rtmp = (char *)(rtm + 1);
        /* Destination */
        if ((rtm->rtm_addrs & RTA_DST) == 0)
                return;         /* ignore routes without destination address */
        sin6_dst = (struct sockaddr_in6 *)(void *)rtmp;
        rtmp += ROUNDUP(sin6_dst->sin6_len);
        if (rtm->rtm_addrs & RTA_GATEWAY) {
                sin6_gw = (struct sockaddr_in6 *)(void *)rtmp;
                rtmp += ROUNDUP(sin6_gw->sin6_len);
        }
        if (rtm->rtm_addrs & RTA_NETMASK) {
                sin6_mask = (struct sockaddr_in6 *)(void *)rtmp;
                rtmp += ROUNDUP(sin6_mask->sin6_len);
        }
        if (rtm->rtm_addrs & RTA_GENMASK) {
                sin6_genmask = (struct sockaddr_in6 *)(void *)rtmp;
                rtmp += ROUNDUP(sin6_genmask->sin6_len);
        }
        if (rtm->rtm_addrs & RTA_IFP) {
                sin6_ifp = (struct sockaddr_in6 *)(void *)rtmp;
                rtmp += ROUNDUP(sin6_ifp->sin6_len);
        }

        /* Destination */
        if (sin6_dst->sin6_family != AF_INET6)
                return;
        if (IN6_IS_ADDR_LINKLOCAL(&sin6_dst->sin6_addr))
                return;         /* Link-local */
        if (IN6_ARE_ADDR_EQUAL(&sin6_dst->sin6_addr, &in6addr_loopback))
                return;         /* Loopback */
        if (IN6_IS_ADDR_MULTICAST(&sin6_dst->sin6_addr))
                return;

        if ((rrt = MALLOC(struct riprt)) == NULL) {
                fatal("malloc: struct riprt");
                /*NOTREACHED*/
        }
        memset(rrt, 0, sizeof(*rrt));
        np = &rrt->rrt_info;
        rrt->rrt_same = NULL;
        rrt->rrt_t = time(NULL);
        if (aflag == 0 && (rtm->rtm_flags & RTF_STATIC))
                rrt->rrt_t = 0; /* Don't age static routes */
        if (rtm->rtm_flags & Pflag)
                rrt->rrt_t = 0; /* Don't age PROTO[123] routes */
        if ((rtm->rtm_flags & (RTF_HOST|RTF_GATEWAY)) == RTF_HOST)
                rrt->rrt_t = 0; /* Don't age non-gateway host routes */
        np->rip6_tag = 0;
        np->rip6_metric = rtm->rtm_rmx.rmx_hopcount;
        if (np->rip6_metric < 1)
                np->rip6_metric = 1;
        rrt->rrt_flags = rtm->rtm_flags;
        np->rip6_dest = sin6_dst->sin6_addr;

        /* Mask or plen */
        if (rtm->rtm_flags & RTF_HOST)
                np->rip6_plen = 128;    /* Host route */
        else if (sin6_mask)
                np->rip6_plen = sin6mask2len(sin6_mask);
        else
                np->rip6_plen = 0;

        orrt = rtsearch(np);
        if (orrt && orrt->rrt_info.rip6_metric != HOPCNT_INFINITY6) {
                /* Already found */
                if (!again) {
                        trace(1, "route: %s/%d flags %s: already registered\n",
                                inet6_n2p(&np->rip6_dest), np->rip6_plen,
                                rtflags(rtm));
                }
                free(rrt);
                return;
        }
        /* Gateway */
        if (!sin6_gw)
                memset(&rrt->rrt_gw, 0, sizeof(struct in6_addr));
        else {
                if (sin6_gw->sin6_family == AF_INET6)
                        rrt->rrt_gw = sin6_gw->sin6_addr;
                else if (sin6_gw->sin6_family == AF_LINK) {
                        /* XXX in case ppp link? */
                        rrt->rrt_gw = in6addr_loopback;
                } else
                        memset(&rrt->rrt_gw, 0, sizeof(struct in6_addr));
        }
        trace(1, "route: %s/%d flags %s",
                inet6_n2p(&np->rip6_dest), np->rip6_plen, rtflags(rtm));
        trace(1, " gw %s", inet6_n2p(&rrt->rrt_gw));

        /* Interface */
        ifindex = rtm->rtm_index;
        if ((unsigned int)ifindex < nindex2ifc && index2ifc[ifindex])
                ifname = index2ifc[ifindex]->ifc_name;
        else {
                trace(1, " not configured\n");
                free(rrt);
                return;
        }
        trace(1, " if %s sock %d", ifname, ifindex);
        rrt->rrt_index = ifindex;

        trace(1, "\n");

        /* Check gateway */
        if (!IN6_IS_ADDR_LINKLOCAL(&rrt->rrt_gw) &&
            !IN6_IS_ADDR_LOOPBACK(&rrt->rrt_gw) &&
            (rrt->rrt_flags & RTF_LOCAL) == 0) {
                trace(0, "***** Gateway %s is not a link-local address.\n",
                        inet6_n2p(&rrt->rrt_gw));
                trace(0, "*****     dest(%s) if(%s) -- Not optimized.\n",
                        inet6_n2p(&rrt->rrt_info.rip6_dest), ifname);
                rrt->rrt_rflags |= RRTF_NH_NOT_LLADDR;
        }

        /* Put it to the route list */
        if (orrt && orrt->rrt_info.rip6_metric == HOPCNT_INFINITY6) {
                /* replace route list */
                TAILQ_INSERT_BEFORE(orrt, rrt, rrt_next);
                TAILQ_REMOVE(&riprt_head, orrt, rrt_next);

                trace(1, "route: %s/%d flags %s: replace new route\n",
                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                    rtflags(rtm));
                free(orrt);
        } else
                TAILQ_INSERT_HEAD(&riprt_head, rrt, rrt_next);
}

static int
addroute(struct riprt *rrt,
        const struct in6_addr *gw,
        struct ifc *ifcp)
{
        struct  netinfo6 *np;
        u_char  buf[BUFSIZ], buf1[BUFSIZ], buf2[BUFSIZ];
        struct  rt_msghdr       *rtm;
        struct  sockaddr_in6    *sin6;
        int     len;

        np = &rrt->rrt_info;
        inet_ntop(AF_INET6, (const void *)gw, (char *)buf1, sizeof(buf1));
        inet_ntop(AF_INET6, (void *)&ifcp->ifc_mylladdr, (char *)buf2, sizeof(buf2));
        tracet(1, "ADD: %s/%d gw %s [%d] ifa %s\n",
                inet6_n2p(&np->rip6_dest), np->rip6_plen, buf1,
                np->rip6_metric - 1, buf2);
        if (rtlog)
                fprintf(rtlog, "%s: ADD: %s/%d gw %s [%d] ifa %s\n", hms(),
                        inet6_n2p(&np->rip6_dest), np->rip6_plen, buf1,
                        np->rip6_metric - 1, buf2);
        if (nflag)
                return 0;

        memset(buf, 0, sizeof(buf));
        rtm = (struct rt_msghdr *)(void *)buf;
        rtm->rtm_type = RTM_ADD;
        rtm->rtm_version = RTM_VERSION;
        rtm->rtm_seq = ++seq;
        rtm->rtm_pid = pid;
        rtm->rtm_flags = rrt->rrt_flags;
        rtm->rtm_flags |= Qflag;
        rtm->rtm_addrs = RTA_DST | RTA_GATEWAY | RTA_NETMASK;
        rtm->rtm_rmx.rmx_hopcount = np->rip6_metric - 1;
        rtm->rtm_inits = RTV_HOPCOUNT;
        sin6 = (struct sockaddr_in6 *)(void *)&buf[sizeof(struct rt_msghdr)];
        /* Destination */
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_addr = np->rip6_dest;
        sin6 = (struct sockaddr_in6 *)(void *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
        /* Gateway */
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_addr = *gw;
        if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
                sin6->sin6_scope_id = ifcp->ifc_index;
        sin6 = (struct sockaddr_in6 *)(void *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
        /* Netmask */
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_addr = *(plen2mask(np->rip6_plen));
        sin6 = (struct sockaddr_in6 *)(void *)((char *)sin6 + ROUNDUP(sin6->sin6_len));

        len = (char *)sin6 - (char *)buf;
        rtm->rtm_msglen = len;
        if (write(rtsock, buf, len) > 0)
                return 0;

        if (errno == EEXIST) {
                trace(0, "ADD: Route already exists %s/%d gw %s\n",
                    inet6_n2p(&np->rip6_dest), np->rip6_plen, buf1);
                if (rtlog)
                        fprintf(rtlog, "ADD: Route already exists %s/%d gw %s\n",
                            inet6_n2p(&np->rip6_dest), np->rip6_plen, buf1);
        } else {
                trace(0, "Can not write to rtsock (addroute): %s\n",
                    strerror(errno));
                if (rtlog)
                        fprintf(rtlog, "\tCan not write to rtsock: %s\n",
                            strerror(errno));
        }
        return -1;
}

static int
delroute(struct netinfo6 *np, struct in6_addr *gw)
{
        u_char  buf[BUFSIZ], buf2[BUFSIZ];
        struct  rt_msghdr       *rtm;
        struct  sockaddr_in6    *sin6;
        int     len;

        inet_ntop(AF_INET6, (void *)gw, (char *)buf2, sizeof(buf2));
        tracet(1, "DEL: %s/%d gw %s\n", inet6_n2p(&np->rip6_dest),
                np->rip6_plen, buf2);
        if (rtlog)
                fprintf(rtlog, "%s: DEL: %s/%d gw %s\n",
                        hms(), inet6_n2p(&np->rip6_dest), np->rip6_plen, buf2);
        if (nflag)
                return 0;

        memset(buf, 0, sizeof(buf));
        rtm = (struct rt_msghdr *)(void *)buf;
        rtm->rtm_type = RTM_DELETE;
        rtm->rtm_version = RTM_VERSION;
        rtm->rtm_seq = ++seq;
        rtm->rtm_pid = pid;
        rtm->rtm_flags = RTF_UP | RTF_GATEWAY;
        rtm->rtm_flags |= Qflag;
        if (np->rip6_plen == sizeof(struct in6_addr) * 8)
                rtm->rtm_flags |= RTF_HOST;
        rtm->rtm_addrs = RTA_DST | RTA_GATEWAY | RTA_NETMASK;
        sin6 = (struct sockaddr_in6 *)(void *)&buf[sizeof(struct rt_msghdr)];
        /* Destination */
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_addr = np->rip6_dest;
        sin6 = (struct sockaddr_in6 *)(void *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
        /* Gateway */
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_addr = *gw;
        sin6 = (struct sockaddr_in6 *)(void *)((char *)sin6 + ROUNDUP(sin6->sin6_len));
        /* Netmask */
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_addr = *(plen2mask(np->rip6_plen));
        sin6 = (struct sockaddr_in6 *)(void *)((char *)sin6 + ROUNDUP(sin6->sin6_len));

        len = (char *)sin6 - (char *)buf;
        rtm->rtm_msglen = len;
        if (write(rtsock, buf, len) >= 0)
                return 0;

        if (errno == ESRCH) {
                trace(0, "RTDEL: Route does not exist: %s/%d gw %s\n",
                    inet6_n2p(&np->rip6_dest), np->rip6_plen, buf2);
                if (rtlog)
                        fprintf(rtlog, "RTDEL: Route does not exist: %s/%d gw %s\n",
                            inet6_n2p(&np->rip6_dest), np->rip6_plen, buf2);
        } else {
                trace(0, "Can not write to rtsock (delroute): %s\n",
                    strerror(errno));
                if (rtlog)
                        fprintf(rtlog, "\tCan not write to rtsock: %s\n",
                            strerror(errno));
        }
        return -1;
}

#if 0
static struct in6_addr *
getroute(struct netinfo6 *np, struct in6_addr *gw)
{
        u_char buf[BUFSIZ];
        int myseq;
        int len;
        struct rt_msghdr *rtm;
        struct sockaddr_in6 *sin6;

        rtm = (struct rt_msghdr *)(void *)buf;
        len = sizeof(struct rt_msghdr) + sizeof(struct sockaddr_in6);
        memset(rtm, 0, len);
        rtm->rtm_type = RTM_GET;
        rtm->rtm_version = RTM_VERSION;
        myseq = ++seq;
        rtm->rtm_seq = myseq;
        rtm->rtm_addrs = RTA_DST;
        rtm->rtm_msglen = len;
        sin6 = (struct sockaddr_in6 *)(void *)&buf[sizeof(struct rt_msghdr)];
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_addr = np->rip6_dest;
        if (write(rtsock, buf, len) < 0) {
                if (errno == ESRCH)     /* No such route found */
                        return NULL;
                perror("write to rtsock");
                exit(1);
        }
        do {
                if ((len = read(rtsock, buf, sizeof(buf))) < 0) {
                        perror("read from rtsock");
                        exit(1);
                }
                rtm = (struct rt_msghdr *)(void *)buf;
        } while (rtm->rtm_type != RTM_GET || rtm->rtm_seq != myseq ||
            rtm->rtm_pid != pid);
        sin6 = (struct sockaddr_in6 *)(void *)&buf[sizeof(struct rt_msghdr)];
        if (rtm->rtm_addrs & RTA_DST) {
                sin6 = (struct sockaddr_in6 *)(void *)
                        ((char *)sin6 + ROUNDUP(sin6->sin6_len));
        }
        if (rtm->rtm_addrs & RTA_GATEWAY) {
                *gw = sin6->sin6_addr;
                return gw;
        }
        return NULL;
}
#endif

static const char *
inet6_n2p(const struct in6_addr *p)
{
        static char buf[BUFSIZ];

        return inet_ntop(AF_INET6, (const void *)p, buf, sizeof(buf));
}

static void
ifrtdump(int sig)
{

        ifdump(sig);
        rtdump(sig);
}

static void
ifdump(int sig)
{
        struct ifc *ifcp;
        FILE *dump;
        int nifc = 0;

        if (sig == 0)
                dump = stderr;
        else
                if ((dump = fopen(ROUTE6D_DUMP, "a")) == NULL)
                        dump = stderr;

        fprintf(dump, "%s: Interface Table Dump\n", hms());
        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next)
                nifc++;
        fprintf(dump, "  Number of interfaces: %d\n", nifc);

        fprintf(dump, "  advertising interfaces:\n");
        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                if ((ifcp->ifc_flags & IFF_UP) == 0)
                        continue;
                if (iff_find(ifcp, IFIL_TYPE_N) != NULL)
                        continue;
                ifdump0(dump, ifcp);
        }
        fprintf(dump, "\n");
        fprintf(dump, "  non-advertising interfaces:\n");
        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                if ((ifcp->ifc_flags & IFF_UP) &&
                    (iff_find(ifcp, IFIL_TYPE_N) == NULL))
                        continue;
                ifdump0(dump, ifcp);
        }
        fprintf(dump, "\n");
        if (dump != stderr)
                fclose(dump);
}

static void
ifdump0(FILE *dump, const struct ifc *ifcp)
{
        struct ifac *ifac;
        struct iff *iffp;
        char buf[BUFSIZ];
        const char *ft;
        int addr;

        fprintf(dump, "    %s: index(%d) flags(%s) addr(%s) mtu(%d) metric(%d)\n",
                ifcp->ifc_name, ifcp->ifc_index, ifflags(ifcp->ifc_flags),
                inet6_n2p(&ifcp->ifc_mylladdr),
                ifcp->ifc_mtu, ifcp->ifc_metric);
        TAILQ_FOREACH(ifac, &ifcp->ifc_ifac_head, ifac_next) {
                if (ifcp->ifc_flags & IFF_POINTOPOINT) {
                        inet_ntop(AF_INET6, (void *)&ifac->ifac_raddr,
                                buf, sizeof(buf));
                        fprintf(dump, "\t%s/%d -- %s\n",
                                inet6_n2p(&ifac->ifac_addr),
                                ifac->ifac_plen, buf);
                } else {
                        fprintf(dump, "\t%s/%d\n",
                                inet6_n2p(&ifac->ifac_addr),
                                ifac->ifac_plen);
                }
        }

        fprintf(dump, "\tFilter:\n");
        TAILQ_FOREACH(iffp, &ifcp->ifc_iff_head, iff_next) {
                addr = 0;
                switch (iffp->iff_type) {
                case IFIL_TYPE_A:
                        ft = "Aggregate"; addr++; break;
                case IFIL_TYPE_N:
                        ft = "No-use"; break;
                case IFIL_TYPE_O:
                        ft = "Advertise-only"; addr++; break;
                case IFIL_TYPE_T:
                        ft = "Default-only"; break;
                case IFIL_TYPE_L:
                        ft = "Listen-only"; addr++; break;
                default:
                        snprintf(buf, sizeof(buf), "Unknown-%c", iffp->iff_type);
                        ft = buf;
                        addr++;
                        break;
                }
                fprintf(dump, "\t\t%s", ft);
                if (addr)
                        fprintf(dump, "(%s/%d)", inet6_n2p(&iffp->iff_addr),
                                iffp->iff_plen);
                fprintf(dump, "\n");
        }
        fprintf(dump, "\n");
}

static void
rtdump(int sig)
{
        struct  riprt *rrt;
        char    buf[BUFSIZ];
        FILE    *dump;
        time_t  t, age;

        if (sig == 0)
                dump = stderr;
        else
                if ((dump = fopen(ROUTE6D_DUMP, "a")) == NULL)
                        dump = stderr;

        t = time(NULL);
        fprintf(dump, "\n%s: Routing Table Dump\n", hms());
        TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                if (rrt->rrt_t == 0)
                        age = 0;
                else
                        age = t - rrt->rrt_t;
                inet_ntop(AF_INET6, (void *)&rrt->rrt_info.rip6_dest,
                        buf, sizeof(buf));
                fprintf(dump, "    %s/%d if(%d:%s) gw(%s) [%d] age(%ld)",
                        buf, rrt->rrt_info.rip6_plen, rrt->rrt_index,
                        index2ifc[rrt->rrt_index]->ifc_name,
                        inet6_n2p(&rrt->rrt_gw),
                        rrt->rrt_info.rip6_metric, (long)age);
                if (rrt->rrt_info.rip6_tag) {
                        fprintf(dump, " tag(0x%04x)",
                                ntohs(rrt->rrt_info.rip6_tag) & 0xffff);
                }
                if (rrt->rrt_rflags & RRTF_NH_NOT_LLADDR)
                        fprintf(dump, " NOT-LL");
                if (rrt->rrt_rflags & RRTF_NOADVERTISE)
                        fprintf(dump, " NO-ADV");
                fprintf(dump, "\n");
        }
        fprintf(dump, "\n");
        if (dump != stderr)
                fclose(dump);
}

/*
 * Parse the -A (and -O) options and put corresponding filter object to the
 * specified interface structures.  Each of the -A/O option has the following
 * syntax:      -A 5f09:c400::/32,ef0,ef1  (aggregate)
 *              -O 5f09:c400::/32,ef0,ef1  (only when match)
 */
static void
filterconfig(void)
{
        int i;
        char *p, *ap, *iflp, *ifname, *ep;
        struct iff iff, *iffp;
        struct ifc *ifcp;
        struct riprt *rrt;
#if 0
        struct in6_addr gw;
#endif
        u_long plen;

        for (i = 0; i < nfilter; i++) {
                ap = filter[i];
                iflp = NULL;
                iffp = &iff;
                memset(iffp, 0, sizeof(*iffp));
                if (filtertype[i] == 'N' || filtertype[i] == 'T') {
                        iflp = ap;
                        goto ifonly;
                }
                if ((p = strchr(ap, ',')) != NULL) {
                        *p++ = '\0';
                        iflp = p;
                }
                if ((p = strchr(ap, '/')) == NULL) {
                        fatal("no prefixlen specified for '%s'", ap);
                        /*NOTREACHED*/
                }
                *p++ = '\0';
                if (inet_pton(AF_INET6, ap, &iffp->iff_addr) != 1) {
                        fatal("invalid prefix specified for '%s'", ap);
                        /*NOTREACHED*/
                }
                errno = 0;
                ep = NULL;
                plen = strtoul(p, &ep, 10);
                if (errno || !*p || *ep || plen > sizeof(iffp->iff_addr) * 8) {
                        fatal("invalid prefix length specified for '%s'", ap);
                        /*NOTREACHED*/
                }
                iffp->iff_plen = plen;
                applyplen(&iffp->iff_addr, iffp->iff_plen);
ifonly:
                iffp->iff_type = filtertype[i];
                if (iflp == NULL || *iflp == '\0') {
                        fatal("no interface specified for '%s'", ap);
                        /*NOTREACHED*/
                }
                /* parse the interface listing portion */
                while (iflp) {
                        ifname = iflp;
                        if ((iflp = strchr(iflp, ',')) != NULL)
                                *iflp++ = '\0';

                        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                                if (fnmatch(ifname, ifcp->ifc_name, 0) != 0)
                                        continue;

                                iffp = malloc(sizeof(*iffp));
                                if (iffp == NULL) {
                                        fatal("malloc of iff");
                                        /*NOTREACHED*/
                                }
                                memcpy(iffp, &iff, sizeof(*iffp));
#if 0
                                syslog(LOG_INFO, "Add filter: type %d, ifname %s.", iffp->iff_type, ifname);
#endif
                                TAILQ_INSERT_HEAD(&ifcp->ifc_iff_head, iffp, iff_next);
                        }
                }

                /*
                 * -A: aggregate configuration.
                 */
                if (filtertype[i] != IFIL_TYPE_A)
                        continue;
                /* put the aggregate to the kernel routing table */
                rrt = (struct riprt *)malloc(sizeof(struct riprt));
                if (rrt == NULL) {
                        fatal("malloc: rrt");
                        /*NOTREACHED*/
                }
                memset(rrt, 0, sizeof(struct riprt));
                rrt->rrt_info.rip6_dest = iff.iff_addr;
                rrt->rrt_info.rip6_plen = iff.iff_plen;
                rrt->rrt_info.rip6_metric = 1;
                rrt->rrt_info.rip6_tag = htons(routetag & 0xffff);
                rrt->rrt_gw = in6addr_loopback;
                rrt->rrt_flags = RTF_UP | RTF_REJECT;
                rrt->rrt_rflags = RRTF_AGGREGATE;
                rrt->rrt_t = 0;
                rrt->rrt_index = loopifcp->ifc_index;
#if 0
                if (getroute(&rrt->rrt_info, &gw)) {
#if 0
                        /*
                         * When the address has already been registered in the
                         * kernel routing table, it should be removed
                         */
                        delroute(&rrt->rrt_info, &gw);
#else
                        /* it is safer behavior */
                        errno = EINVAL;
                        fatal("%s/%u already in routing table, "
                            "cannot aggregate",
                            inet6_n2p(&rrt->rrt_info.rip6_dest),
                            rrt->rrt_info.rip6_plen);
                        /*NOTREACHED*/
#endif
                }
#endif
                /* Put the route to the list */
                TAILQ_INSERT_HEAD(&riprt_head, rrt, rrt_next);
                trace(1, "Aggregate: %s/%d for %s\n",
                        inet6_n2p(&iff.iff_addr), iff.iff_plen,
                        loopifcp->ifc_name);
                /* Add this route to the kernel */
                if (nflag)      /* do not modify kernel routing table */
                        continue;
                addroute(rrt, &in6addr_loopback, loopifcp);
        }
}

/***************** utility functions *****************/

/*
 * Returns a pointer to ifac whose address and prefix length matches
 * with the address and prefix length specified in the arguments.
 */
static struct ifac *
ifa_match(const struct ifc *ifcp,
        const struct in6_addr *ia,
        int plen)
{
        struct ifac *ifac;

        TAILQ_FOREACH(ifac, &ifcp->ifc_ifac_head, ifac_next) {
                if (IN6_ARE_ADDR_EQUAL(&ifac->ifac_addr, ia) &&
                    ifac->ifac_plen == plen)
                        break;
        }

        return (ifac);
}

/*
 * Return a pointer to riprt structure whose address and prefix length
 * matches with the address and prefix length found in the argument.
 * Note: This is not a rtalloc().  Therefore exact match is necessary.
 */
static struct riprt *
rtsearch(struct netinfo6 *np)
{
        struct  riprt   *rrt;

        TAILQ_FOREACH(rrt, &riprt_head, rrt_next) {
                if (rrt->rrt_info.rip6_plen == np->rip6_plen &&
                    IN6_ARE_ADDR_EQUAL(&rrt->rrt_info.rip6_dest,
                                       &np->rip6_dest))
                        break;
        }

        return (rrt);
}

static int
sin6mask2len(const struct sockaddr_in6 *sin6)
{

        return mask2len(&sin6->sin6_addr,
            sin6->sin6_len - offsetof(struct sockaddr_in6, sin6_addr));
}

static int
mask2len(const struct in6_addr *addr, int lenlim)
{
        int i = 0, j;
        const u_char *p = (const u_char *)addr;

        for (j = 0; j < lenlim; j++, p++) {
                if (*p != 0xff)
                        break;
                i += 8;
        }
        if (j < lenlim) {
                switch (*p) {
#define MASKLEN(m, l)   case m: do { i += l; break; } while (0)
                MASKLEN(0xfe, 7); break;
                MASKLEN(0xfc, 6); break;
                MASKLEN(0xf8, 5); break;
                MASKLEN(0xf0, 4); break;
                MASKLEN(0xe0, 3); break;
                MASKLEN(0xc0, 2); break;
                MASKLEN(0x80, 1); break;
#undef  MASKLEN
                }
        }
        return i;
}

static const u_char plent[8] = {
        0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe
};

static void
applyplen(struct in6_addr *ia, int plen)
{
        u_char  *p;
        int     i;

        p = ia->s6_addr;
        for (i = 0; i < 16; i++) {
                if (plen <= 0)
                        *p = 0;
                else if (plen < 8)
                        *p &= plent[plen];
                p++, plen -= 8;
        }
}

static const int pl2m[9] = {
        0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
};

static struct in6_addr *
plen2mask(int n)
{
        static struct in6_addr ia;
        u_char  *p;
        int     i;

        memset(&ia, 0, sizeof(struct in6_addr));
        p = (u_char *)&ia;
        for (i = 0; i < 16; i++, p++, n -= 8) {
                if (n >= 8) {
                        *p = 0xff;
                        continue;
                }
                *p = pl2m[n];
                break;
        }
        return &ia;
}

static char *
allocopy(char *p)
{
        int len = strlen(p) + 1;
        char *q = (char *)malloc(len);

        if (!q) {
                fatal("malloc");
                /*NOTREACHED*/
        }

        strlcpy(q, p, len);
        return q;
}

static char *
hms(void)
{
        static char buf[BUFSIZ];
        time_t t;
        struct  tm *tm;

        t = time(NULL);
        if ((tm = localtime(&t)) == 0) {
                fatal("localtime");
                /*NOTREACHED*/
        }
        snprintf(buf, sizeof(buf), "%02d:%02d:%02d", tm->tm_hour, tm->tm_min,
            tm->tm_sec);
        return buf;
}

#define RIPRANDDEV      1.0     /* 30 +- 15, max - min = 30 */

static int
ripinterval(int timer)
{
        double r = rand();

        interval = (int)(timer + timer * RIPRANDDEV * (r / RAND_MAX - 0.5));
        nextalarm = time(NULL) + interval;
        return interval;
}

#if 0
static time_t
ripsuptrig(void)
{
        time_t t;

        double r = rand();
        t  = (int)(RIP_TRIG_INT6_MIN +
                (RIP_TRIG_INT6_MAX - RIP_TRIG_INT6_MIN) * (r / RAND_MAX));
        sup_trig_update = time(NULL) + t;
        return t;
}
#endif

static void
fatal(const char *fmt, ...)
{
        va_list ap;
        char buf[1024];

        va_start(ap, fmt);
        vsnprintf(buf, sizeof(buf), fmt, ap);
        va_end(ap);
        perror(buf);
        if (errno)
                syslog(LOG_ERR, "%s: %s", buf, strerror(errno));
        else
                syslog(LOG_ERR, "%s", buf);
        rtdexit();
}

static void
tracet(int level, const char *fmt, ...)
{
        va_list ap;

        if (level <= dflag) {
                va_start(ap, fmt);
                fprintf(stderr, "%s: ", hms());
                vfprintf(stderr, fmt, ap);
                va_end(ap);
        }
        if (dflag) {
                va_start(ap, fmt);
                if (level > 0)
                        vsyslog(LOG_DEBUG, fmt, ap);
                else
                        vsyslog(LOG_WARNING, fmt, ap);
                va_end(ap);
        }
}

static void
trace(int level, const char *fmt, ...)
{
        va_list ap;

        if (level <= dflag) {
                va_start(ap, fmt);
                vfprintf(stderr, fmt, ap);
                va_end(ap);
        }
        if (dflag) {
                va_start(ap, fmt);
                if (level > 0)
                        vsyslog(LOG_DEBUG, fmt, ap);
                else
                        vsyslog(LOG_WARNING, fmt, ap);
                va_end(ap);
        }
}

static struct ifc *
ifc_find(char *name)
{
        struct ifc *ifcp;

        TAILQ_FOREACH(ifcp, &ifc_head, ifc_next) {
                if (strcmp(name, ifcp->ifc_name) == 0)
                        break;
        }
        return (ifcp);
}

static struct iff *
iff_find(struct ifc *ifcp, int type)
{
        struct iff *iffp;

        TAILQ_FOREACH(iffp, &ifcp->ifc_iff_head, iff_next) {
                if (type == IFIL_TYPE_ANY ||
                    type == iffp->iff_type)
                        break;
        }

        return (iffp);
}

static void
setindex2ifc(int idx, struct ifc *ifcp)
{
        int n, nsize;
        struct ifc **p;

        if (!index2ifc) {
                nindex2ifc = 5; /*initial guess*/
                index2ifc = (struct ifc **)
                        malloc(sizeof(*index2ifc) * nindex2ifc);
                if (index2ifc == NULL) {
                        fatal("malloc");
                        /*NOTREACHED*/
                }
                memset(index2ifc, 0, sizeof(*index2ifc) * nindex2ifc);
        }
        n = nindex2ifc;
        for (nsize = nindex2ifc; nsize <= idx; nsize *= 2)
                ;
        if (n != nsize) {
                p = (struct ifc **)realloc(index2ifc,
                    sizeof(*index2ifc) * nsize);
                if (p == NULL) {
                        fatal("realloc");
                        /*NOTREACHED*/
                }
                memset(p + n, 0, sizeof(*index2ifc) * (nindex2ifc - n));
                index2ifc = p;
                nindex2ifc = nsize;
        }
        index2ifc[idx] = ifcp;
}