/*      $OpenBSD: route6d.c,v 1.101 2024/05/21 05:00:48 jsg Exp $       */
/*      $KAME: route6d.c,v 1.111 2006/10/25 06:38:13 jinmei Exp $       */

/*
 * 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/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/uio.h>

#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet/udp.h>
#include <netinet6/in6_var.h>

#include <arpa/inet.h>
#include <errno.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <poll.h>
#include <signal.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "route6d.h"
#include "log.h"

#define MAXFILTER       40

#ifdef  DEBUG
#define INIT_INTERVAL6  6
#else
#define INIT_INTERVAL6  10      /* Wait to submit a 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))

/*
 * Following two macros are highly depending on KAME Release
 */
#define IN6_LINKLOCAL_IFINDEX(addr) \
        ((addr).s6_addr[2] << 8 | (addr).s6_addr[3])

#define SET_IN6_LINKLOCAL_IFINDEX(addr, index) \
        do { \
                (addr).s6_addr[2] = ((index) >> 8) & 0xff; \
                (addr).s6_addr[3] = (index) & 0xff; \
        } while (0)

struct  ifc {                   /* Configuration of an interface */
        char    *ifc_name;                      /* if name */
        struct  ifc *ifc_next;
        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 */
        struct  iff *ifc_filter;                /* filter structure */
        struct  ifac *ifc_addr;                 /* list of AF_INET6 addresses */
        int     ifc_joined;                     /* joined to ff02::9 */
};

struct  ifac {                  /* Address associated to an interface */ 
        struct  ifc *ifa_conf;          /* back pointer */
        struct  ifac *ifa_next;
        struct  in6_addr ifa_addr;      /* address */
        struct  in6_addr ifa_raddr;     /* remote address, valid in p2p */
        int     ifa_plen;               /* prefix length */
};

struct  iff {
        int     iff_type;
        struct  in6_addr iff_addr;
        int     iff_plen;
        struct  iff *iff_next;
};

struct  ifc *ifc;
int     nifc;           /* number of valid ifc's */
struct  ifc **index2ifc;
int     nindex2ifc;
struct  ifc *loopifcp = NULL;   /* pointing to loopback */
struct  pollfd pfd[2];
int     rtsock;         /* the routing socket */
int     ripsock;        /* socket to send/receive RIP datagram */

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 {
        struct  riprt *rrt_next;        /* next destination */
        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 */
};

struct  riprt *riprt = 0;

int     dflag = 0;      /* debug flag */
int     qflag = 0;      /* quiet flag */
int     nflag = 0;      /* don't update kernel routing table */
int     aflag = 0;      /* age out even the statically defined routes */
int     hflag = 0;      /* don't split horizon */
int     lflag = 0;      /* exchange site local routes */
int     sflag = 0;      /* announce static routes w/ split horizon */
int     Sflag = 0;      /* announce static routes to every interface */
int     uflag = 0;      /* always log route updates (additions/deletions) */
unsigned long routetag = 0;     /* route tag attached on originating case */

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

pid_t   pid;

struct  sockaddr_storage ripsin;

time_t  nextalarm = 0;
time_t  sup_trig_update = 0;

static  int     seq = 0;

volatile sig_atomic_t seenalrm;
volatile sig_atomic_t seenquit;
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

void sighandler(int);
void ripalarm(void);
void riprecv(void);
void ripsend(struct ifc *, struct sockaddr_in6 *, int);
int out_filter(struct riprt *, struct ifc *);
void init(void);
void ifconfig(void);
void ifconfig1(const char *, const struct sockaddr *, struct ifc *, int);
void rtrecv(void);
int rt_del(const struct sockaddr_in6 *, const struct sockaddr_in6 *,
    const struct sockaddr_in6 *);
int rt_deladdr(struct ifc *, const struct sockaddr_in6 *,
    const struct sockaddr_in6 *);
void filterconfig(void);
int getifmtu(int);
const char *rttypes(struct rt_msghdr *);
const char *rtflags(struct rt_msghdr *);
const char *ifflags(int);
int ifrt(struct ifc *, int);
void ifrt_p2p(struct ifc *, int);
void applyplen(struct in6_addr *, int);
void ifrtdump(int);
void ifdump(int);
void ifdump0(const struct ifc *);
void rtdump(int);
void rt_entry(struct rt_msghdr *, int);
__dead void rtdexit(void);
void riprequest(struct ifc *, struct netinfo6 *, int, struct sockaddr_in6 *);
void ripflush(struct ifc *, struct sockaddr_in6 *);
void sendrequest(struct ifc *);
int sin6mask2len(const struct sockaddr_in6 *);
int mask2len(const struct in6_addr *, int);
int sendpacket(struct sockaddr_in6 *, int);
int addroute(struct riprt *, const struct in6_addr *, struct ifc *);
int delroute(struct netinfo6 *, struct in6_addr *);
struct in6_addr *getroute(struct netinfo6 *, struct in6_addr *);
void krtread(int);
int tobeadv(struct riprt *, struct ifc *);
char *xstrdup(const char *);
const char *hms(void);
const char *inet6_n2p(const struct in6_addr *);
struct ifac *ifa_match(const struct ifc *, const struct in6_addr *, int);
struct in6_addr *plen2mask(int);
struct riprt *rtsearch(struct netinfo6 *, struct riprt **);
int ripinterval(int);
time_t ripsuptrig(void);
unsigned int if_maxindex(void);
struct ifc *ifc_find(char *);
struct iff *iff_find(struct ifc *, int);
void setindex2ifc(int, struct ifc *);

int
main(int argc, char *argv[])
{
        int     ch;
        int     error = 0;
        struct  ifc *ifcp;
        sigset_t mask, omask;
        char *ep;

        log_init(1); /* log to stderr until daemonized */

        while ((ch = getopt(argc, argv, "A:N:O:T:L:t:adDhlnqsSu")) != -1) {
                switch (ch) {
                case 'A':
                case 'N':
                case 'O':
                case 'T':
                case 'L':
                        if (nfilter >= MAXFILTER) {
                                fatalx("Exceeds MAXFILTER");
                                /*NOTREACHED*/
                        }
                        filtertype[nfilter] = ch;
                        filter[nfilter++] = xstrdup(optarg);
                        break;
                case 't':
                        ep = NULL;
                        routetag = strtoul(optarg, &ep, 0);
                        if (!ep || *ep != '\0' || (routetag & ~0xffff) != 0) {
                                fatalx("invalid route tag");
                                /*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;
                FLAG('u', uflag, 1); break;
#undef  FLAG
                default:
                        fatalx("Invalid option specified, terminating");
                        /*NOTREACHED*/
                }
        }
        argc -= optind;
        argv += optind;
        if (argc > 0) {
                fatalx("bogus extra arguments");
                /*NOTREACHED*/
        }

        if (geteuid()) {
                nflag = 1;
                log_warn("No kernel update is allowed");
        }

        if (dflag == 0) {
                if (daemon(0, 0) == -1) {
                        fatal("daemon");
                        /*NOTREACHED*/
                }
        }

        log_init(dflag);

        pid = getpid();

        if ((ripbuf = calloc(RIP6_MAXMTU, 1)) == NULL)
                fatal(NULL);
        ripbuf->rip6_cmd = RIP6_RESPONSE;
        ripbuf->rip6_vers = RIP6_VERSION;
        ripbuf->rip6_res1[0] = 0;
        ripbuf->rip6_res1[1] = 0;

        init();

        if (pledge("stdio inet route mcast", NULL) == -1)
                fatal("pledge");

        ifconfig();

        for (ifcp = ifc; ifcp; ifcp = ifcp->ifc_next) {
                if (ifcp->ifc_index < 0) {
                        log_warn(
"No ifindex found at %s (no link-local address?)",
                                ifcp->ifc_name);
                        error++;
                }
        }
        if (error)
                exit(1);
        if (loopifcp == NULL) {
                fatalx("No loopback found");
                /*NOTREACHED*/
        }
        for (ifcp = ifc; ifcp; ifcp = ifcp->ifc_next)
                ifrt(ifcp, 0);
        filterconfig();
        krtread(0);
        if (dflag)
                ifrtdump(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));

        for (ifcp = ifc; ifcp; ifcp = ifcp->ifc_next) {
                if (iff_find(ifcp, 'N'))
                        continue;
                if (ifcp->ifc_index > 0 && (ifcp->ifc_flags & IFF_UP))
                        sendrequest(ifcp);
        }

        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;
                }

                switch (poll(pfd, 2, INFTIM))
                {
                case -1:
                        if (errno != EINTR) {
                                fatal("poll");
                                /*NOTREACHED*/
                        }
                        continue;
                case 0:
                        continue;
                default:
                        if (pfd[0].revents & POLLIN) {
                                sigprocmask(SIG_BLOCK, &mask, &omask);
                                riprecv();
                                sigprocmask(SIG_SETMASK, &omask, NULL);
                        }
                        if (pfd[1].revents & POLLIN) {
                                sigprocmask(SIG_BLOCK, &mask, &omask);
                                rtrecv();
                                sigprocmask(SIG_SETMASK, &omask, NULL);
                        }
                }
        }
}

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.
 */
void
rtdexit(void)
{
        struct  riprt *rrt;

        alarm(0);
        for (rrt = riprt; rrt; rrt = rrt->rrt_next) {
                if (rrt->rrt_rflags & RRTF_AGGREGATE) {
                        delroute(&rrt->rrt_info, &rrt->rrt_gw);
                }
        }
        close(ripsock);
        close(rtsock);
        log_info("**** Terminated ****");
        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.
 */
void
ripalarm(void)
{
        struct  ifc *ifcp;
        struct  riprt *rrt, *rrt_prev, *rrt_next;
        time_t  t_lifetime, t_holddown;

        /* age the RIP routes */
        rrt_prev = 0;
        t_lifetime = time(NULL) - RIP_LIFETIME;
        t_holddown = t_lifetime - RIP_HOLDDOWN;
        for (rrt = riprt; rrt; rrt = rrt_next) {
                rrt_next = rrt->rrt_next;

                if (rrt->rrt_t == 0) {
                        rrt_prev = rrt;
                        continue;
                }
                if (rrt->rrt_t < t_holddown) {
                        if (rrt_prev) {
                                rrt_prev->rrt_next = rrt->rrt_next;
                        } else {
                                riprt = rrt->rrt_next;
                        }
                        delroute(&rrt->rrt_info, &rrt->rrt_gw);
                        free(rrt);
                        continue;
                }
                if (rrt->rrt_t < t_lifetime)
                        rrt->rrt_info.rip6_metric = HOPCNT_INFINITY6;
                rrt_prev = rrt;
        }
        /* Supply updates */
        for (ifcp = ifc; ifcp; ifcp = ifcp->ifc_next) {
                if (ifcp->ifc_index > 0 && (ifcp->ifc_flags & IFF_UP))
                        ripsend(ifcp, &ifcp->ifc_ripsin, 0);
        }
        alarm(ripinterval(SUPPLY_INTERVAL6));
}

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

        ifc = (struct ifc *)NULL;
        nifc = 0;
        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_flags = AI_PASSIVE;
        error = getaddrinfo(NULL, port, &hints, &res);
        if (error) {
                fatalx(gai_strerror(error));
                /*NOTREACHED*/
        }
        if (res->ai_next) {
                fatalx(":: resolved to multiple address");
                /*NOTREACHED*/
        }

        ripsock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
        if (ripsock == -1) {
                fatal("rip socket");
                /*NOTREACHED*/
        }
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_V6ONLY,
            &int1, sizeof(int1)) == -1) {
                fatal("rip IPV6_V6ONLY");
                /*NOTREACHED*/
        }
        if (bind(ripsock, res->ai_addr, res->ai_addrlen) == -1) {
                fatal("rip bind");
                /*NOTREACHED*/
        }
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
            &int255, sizeof(int255)) == -1) {
                fatal("rip IPV6_MULTICAST_HOPS");
                /*NOTREACHED*/
        }
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
            &int0, sizeof(int0)) == -1) {
                fatal("rip IPV6_MULTICAST_LOOP");
                /*NOTREACHED*/
        }

        i = 1;
        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &i,
            sizeof(i)) == -1) {
                fatal("rip IPV6_RECVPKTINFO");
                /*NOTREACHED*/
        }

        if (setsockopt(ripsock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT,
            &int1, sizeof(int1)) == -1) {
                fatal("rip IPV6_RECVHOPLIMIT");
                /*NOTREACHED*/
        }

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

        pfd[0].fd = ripsock;
        pfd[0].events = POLLIN;

        if (nflag == 0) {
                if ((rtsock = socket(AF_ROUTE, SOCK_RAW, 0)) == -1) {
                        fatal("route socket");
                        /*NOTREACHED*/
                }
                pfd[1].fd = rtsock;
                pfd[1].events = POLLIN;
        } else
                pfd[1].fd = -1;

}

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

/*
 * ripflush flushes the rip datagram stored in the rip buffer
 */
static int nrt;
static struct netinfo6 *np;

void
ripflush(struct ifc *ifcp, struct sockaddr_in6 *sin6)
{
        int i;
        int error;

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

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

        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);
                nrt = 0; np = ripbuf->rip6_nets; nh = NULL;
                for (rrt = riprt; rrt; rrt = rrt->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);
                                nh = NULL;
                        }
                }
                if (nrt)        /* Send last packet */
                        ripflush(NULL, sin6);
                return;
        }

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

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

        /* -T: generate default route only */
        if (iff_find(ifcp, '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);
                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;
        for (rrt = riprt; rrt; rrt = rrt->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);
                                np->rip6_dest = rrt->rrt_gw;
                                if (IN6_IS_ADDR_LINKLOCAL(&np->rip6_dest))
                                        SET_IN6_LINKLOCAL_IFINDEX(np->rip6_dest, 0);
                                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);
                        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);
                        nh = NULL;
                }
        }
        if (nrt)        /* Send last packet */
                ripflush(ifcp, sin6);
}

/*
 * outbound filter logic, per-route/interface.
 */
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.
         */ 
        for (iffp = ifcp->ifc_filter; iffp; iffp = iffp->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;
                for (iffp = ifcp->ifc_filter; iffp; iffp = iffp->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, 'O')) {
                ok = 0;
                for (iffp = ifcp->ifc_filter; iffp; iffp = iffp->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.
 */
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.
 */
int
sendpacket(struct sockaddr_in6 *sin6, int len)
{
        struct msghdr m;
        struct cmsghdr *cm;
        struct iovec iov[2];
        union {
                struct cmsghdr hdr;
                u_char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
        } cmsgbuf;
        struct in6_pktinfo *pi;
        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)) {
                /* XXX: do not mix the interface index and link index */
                idx = IN6_LINKLOCAL_IFINDEX(sin6->sin6_addr);
                SET_IN6_LINKLOCAL_IFINDEX(sin6->sin6_addr, 0);
                sin6->sin6_scope_id = idx;
        } 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;
        if (!idx) {
                m.msg_control = NULL;
                m.msg_controllen = 0;
        } else {
                memset(&cmsgbuf, 0, sizeof(cmsgbuf));
                m.msg_control = (caddr_t)&cmsgbuf.buf;
                m.msg_controllen = sizeof(cmsgbuf.buf);
                cm = CMSG_FIRSTHDR(&m);
                cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
                cm->cmsg_level = IPPROTO_IPV6;
                cm->cmsg_type = IPV6_PKTINFO;
                pi = (struct in6_pktinfo *)CMSG_DATA(cm);
                memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr)); /*::*/
                pi->ipi6_ifindex = idx;
        }

        if (sendmsg(ripsock, &m, 0) == -1) {
                log_debug("sendmsg: %s", strerror(errno));
                return errno;
        }

        return 0;
}

/*
 * Receive and process RIP packets.  Update the routes/kernel forwarding
 * table if necessary.
 */
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];
        union {
                struct cmsghdr hdr;
                u_char buf[CMSG_SPACE(sizeof(struct in6_pktinfo)) +
                    CMSG_SPACE(sizeof(int))];
        } cmsgbuf;
        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;
        m.msg_control = (caddr_t)&cmsgbuf.buf;
        m.msg_controllen = sizeof(cmsgbuf.buf);
        if ((len = recvmsg(ripsock, &m, 0)) == -1) {
                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))) {
                                log_debug(
                                    "invalid cmsg length for IPV6_PKTINFO");
                                return;
                        }
                        pi = (struct in6_pktinfo *)(CMSG_DATA(cm));
                        idx = pi->ipi6_ifindex;
                        break;
                case IPV6_HOPLIMIT:
                        if (cm->cmsg_len != CMSG_LEN(sizeof(int))) {
                                log_debug(
                                    "invalid cmsg length for IPV6_HOPLIMIT");
                                return;
                        }
                        hlimp = (int *)CMSG_DATA(cm);
                        break;
                }
        }
        if (idx && IN6_IS_ADDR_LINKLOCAL(&fsock.sin6_addr))
                SET_IN6_LINKLOCAL_IFINDEX(fsock.sin6_addr, idx);

        if (len < sizeof(struct rip6)) {
                log_debug("Packet too short");
                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.
                 */
                log_debug("IPv6 packet information cannot be retrieved");
                return;
        }

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

        if (rp->rip6_vers != RIP6_VERSION) {
                log_debug("Incorrect RIP version %d", 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)) {
                log_debug("Response from non-ll addr: %s",
                    inet6_n2p(&fsock.sin6_addr));
                return;         /* Ignore packets from non-link-local addr */
        }
        if (ntohs(fsock.sin6_port) != RIP6_PORT) {
                log_debug("Response from non-rip port from %s",
                    inet6_n2p(&fsock.sin6_addr));
                return;
        }
        if (IN6_IS_ADDR_MULTICAST(&pi->ipi6_addr) && *hlimp != 255) {
                log_debug(
                    "Response packet with a smaller hop limit (%d) from %s",
                    *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) {
                log_debug(
                    "Response packet possibly from an off-link node: "
                    "from %s to %s hlim=%d",
                    inet6_n2p(&fsock.sin6_addr), inet6_n2p(&pi->ipi6_addr),
                    *hlimp);
                return;
        }

        idx = IN6_LINKLOCAL_IFINDEX(fsock.sin6_addr);
        ifcp = (idx < nindex2ifc) ? index2ifc[idx] : NULL;
        if (!ifcp) {
                log_debug("Packets to unknown interface index %d", 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) {
                log_debug("Invalid command %d", rp->rip6_cmd);
                return; 
        }

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

        log_debug("Recv(%s): from %s.%d info(%zd)",
            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;
                                SET_IN6_LINKLOCAL_IFINDEX(nh, idx);
                                log_debug("\tNexthop: %s", inet6_n2p(&nh));
                        } else if (IN6_IS_ADDR_UNSPECIFIED(&np->rip6_dest)) {
                                nh = fsock.sin6_addr;
                                log_debug("\tNexthop: %s", inet6_n2p(&nh));
                        } else {
                                nh = fsock.sin6_addr;
                                log_debug("\tInvalid Nexthop: %s",
                                    inet6_n2p(&np->rip6_dest));
                        }
                        continue;
                }
                if (IN6_IS_ADDR_MULTICAST(&np->rip6_dest)) {
                        log_debug("\tMulticast netinfo6: %s/%d [%d]",
                                inet6_n2p(&np->rip6_dest),
                                np->rip6_plen, np->rip6_metric);
                        continue;
                }
                if (IN6_IS_ADDR_LOOPBACK(&np->rip6_dest)) {
                        log_debug("\tLoopback netinfo6: %s/%d [%d]",
                                inet6_n2p(&np->rip6_dest),
                                np->rip6_plen, np->rip6_metric);
                        continue;
                }
                if (IN6_IS_ADDR_LINKLOCAL(&np->rip6_dest)) {
                        log_debug("\tLink Local netinfo6: %s/%d [%d]",
                                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) {
                        log_debug("\tSite Local netinfo6: %s/%d [%d]",
                                inet6_n2p(&np->rip6_dest),
                                np->rip6_plen, np->rip6_metric);
                        continue;
                }
                if (dflag >= 2) {
                        log_enqueue("\tnetinfo6: %s/%d [%d]",
                            inet6_n2p(&np->rip6_dest),
                            np->rip6_plen, np->rip6_metric);
                        if (np->rip6_tag)
                                log_enqueue("  tag=0x%04x",
                                    ntohs(np->rip6_tag) & 0xffff);
                        ia = np->rip6_dest;
                        applyplen(&ia, np->rip6_plen);
                        if (!IN6_ARE_ADDR_EQUAL(&ia, &np->rip6_dest))
                                log_enqueue(" [junk outside prefix]");
                }

                /*
                 * -L: listen only if the prefix matches the configuration
                 */
                ok = 1;         /* if there's no L filter, it is ok */
                for (iffp = ifcp->ifc_filter; iffp; iffp = iffp->iff_next) {
                        if (iffp->iff_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) {
                        if (dflag >= 2)
                                log_debug("  (filtered)");
                        continue;
                }

                if (dflag >= 2)
                        log_debug("");

                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)) != 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 = calloc(1, sizeof(struct riprt))) == NULL) {
                                fatal("calloc: struct riprt");
                                /*NOTREACHED*/
                        }
                        nq = &rrt->rrt_info;

                        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;

                        /* Put the route to the list */
                        rrt->rrt_next = riprt;
                        riprt = rrt;
                        /* Update routing table */
                        addroute(rrt, &nh, ifcp);
                        rrt->rrt_rflags |= RRTF_CHANGED;
                        need_trigger = 1;
                        rrt->rrt_t = t;
                }
        }
        /* XXX need to care the interval between triggered updates */
        if (need_trigger) {
                if (nextalarm > time(NULL) + RIP_TRIG_INT6_MAX) {
                        for (ic = ifc; ic; ic = ic->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 */
                for (rrt = riprt; rrt; rrt = rrt->rrt_next)
                        rrt->rrt_rflags &= ~RRTF_CHANGED;
        }
}

/*
 * Send all routes request packet to the specified interface.
 */
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;
        log_debug("Send rtdump Request to %s (%s)",
                ifcp->ifc_name, inet6_n2p(&ifcp->ifc_ripsin.sin6_addr));
        error = sendpacket(&ifcp->ifc_ripsin, RIPSIZE(1));
        if (error == EAFNOSUPPORT) {
                /* Protocol not supported */
                log_debug("Could not send rtdump Request to %s (%s): "
                        "set IFF_UP to 0",
                        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.
 */
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 */
                log_debug("\tRIP Request");
                for (i = 0; i < nn; i++, np++) {
                        rrt = rtsearch(np, NULL);
                        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 */
        log_debug("\tRIP Request -- whole routing table");
        ripsend(ifcp, sin6, RRTF_SENDANYWAY);
}

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

        if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) == -1) {
                fatal("socket");
                /*NOTREACHED*/
        }

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

        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                if (ifa->ifa_addr == NULL ||
                    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 = calloc(1, sizeof(struct ifc))) == NULL) {
                                fatal("calloc: struct ifc");
                                /*NOTREACHED*/
                        }
                        ifcp->ifc_index = -1;
                        ifcp->ifc_next = ifc;
                        ifc = ifcp;
                        nifc++;
                        ifcp->ifc_name = xstrdup(ifa->ifa_name);
                        ifcp->ifc_addr = 0;
                        ifcp->ifc_filter = 0;
                        ifcp->ifc_flags = ifa->ifa_flags;
                        log_debug("newif %s <%s>", 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) {
                                log_enqueue("%s: <%s> -> ", ifcp->ifc_name,
                                        ifflags(ifcp->ifc_flags));
                                log_debug("<%s>", ifflags(ifa->ifa_flags));
                                ifcp->ifc_cflags |= IFC_CHANGED;
                        }
                        ifcp->ifc_flags = ifa->ifa_flags;
                }
                ifconfig1(ifa->ifa_name, ifa->ifa_addr, ifcp, s);
                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)) == -1) {
                                fatalx("IPV6_JOIN_GROUP");
                                /*NOTREACHED*/
                        }
                        log_debug("join %s %s", ifcp->ifc_name, RIP6_DEST);
                        ifcp->ifc_joined++;
                }
        }
        close(s);
        freeifaddrs(ifap);
}

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

        sin6 = (const struct sockaddr_in6 *)sa;
        if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr) && !lflag)
                return;
        ifr.ifr_addr = *sin6;
        strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        if (ioctl(s, SIOCGIFNETMASK_IN6, (char *)&ifr) == -1) {
                fatal("ioctl: SIOCGIFNETMASK_IN6");
                /*NOTREACHED*/
        }
        plen = sin6mask2len(&ifr.ifr_addr);
        if ((ifa = ifa_match(ifcp, &sin6->sin6_addr, plen)) != NULL) {
                /* same interface found */
                /* need check if something changed */
                /* XXX not yet implemented */
                return;
        }
        /*
         * New address is found
         */
        if ((ifa = calloc(1, sizeof(struct ifac))) == NULL) {
                fatal("calloc: struct ifac");
                /*NOTREACHED*/
        }
        ifa->ifa_conf = ifcp;
        ifa->ifa_next = ifcp->ifc_addr;
        ifcp->ifc_addr = ifa;
        ifa->ifa_addr = sin6->sin6_addr;
        ifa->ifa_plen = plen;
        if (ifcp->ifc_flags & IFF_POINTOPOINT) {
                ifr.ifr_addr = *sin6;
                if (ioctl(s, SIOCGIFDSTADDR_IN6, (char *)&ifr) == -1) {
                        fatal("ioctl: SIOCGIFDSTADDR_IN6");
                        /*NOTREACHED*/
                }
                ifa->ifa_raddr = ifr.ifr_dstaddr.sin6_addr;
                inet_ntop(AF_INET6, (void *)&ifa->ifa_raddr, buf, sizeof(buf));
                log_debug("found address %s/%d -- %s",
                        inet6_n2p(&ifa->ifa_addr), ifa->ifa_plen, buf);
        } else {
                log_debug("found address %s/%d",
                        inet6_n2p(&ifa->ifa_addr), ifa->ifa_plen);
        }
        if (ifcp->ifc_index < 0 && IN6_IS_ADDR_LINKLOCAL(&ifa->ifa_addr)) {
                ifcp->ifc_mylladdr = ifa->ifa_addr;
                ifcp->ifc_index = IN6_LINKLOCAL_IFINDEX(ifa->ifa_addr);
                memcpy(&ifcp->ifc_ripsin, &ripsin, ripsin.ss_len);
                SET_IN6_LINKLOCAL_IFINDEX(ifcp->ifc_ripsin.sin6_addr,
                        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) == -1) {
                        fatal("ioctl: SIOCGIFMETRIC");
                        /*NOTREACHED*/
                }
                ifcp->ifc_metric = ifr.ifr_metric;
                log_debug("\tindex: %d, mtu: %d, metric: %d",
                        ifcp->ifc_index, ifcp->ifc_mtu, ifcp->ifc_metric);
        } else
                ifcp->ifc_cflags |= IFC_CHANGED;
}

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

        if ((len = read(rtsock, buf, sizeof(buf))) == -1) {
                perror("read from rtsock");
                exit(1);
        }
        if (len < sizeof(*rtm)) {
                log_debug("short read from rtsock: %d (should be > %zu)",
                        len, sizeof(*rtm));
                return;
        }
        if (dflag >= 2) {
                log_debug("rtmsg:");
                for (i = 0; i < len; i++) {
                        log_enqueue("%02x ", buf[i] & 0xff);
                        if (i % 16 == 15)
                                log_debug("");
                }
                log_debug("");
        }

        p = buf;
        /* safety against bogus message */
        if (((struct rt_msghdr *)p)->rtm_msglen <= 0) {
                log_debug("bogus rtmsg: length=%d",
                    ((struct rt_msghdr *)p)->rtm_msglen);
                return;
        }
        if (((struct rt_msghdr *)p)->rtm_version != RTM_VERSION)
                return;

        rtm = NULL;
        ifam = NULL;
        ifm = NULL;
        switch (((struct rt_msghdr *)p)->rtm_type) {
        case RTM_NEWADDR:
        case RTM_DELADDR:
                ifam = (struct ifa_msghdr *)p;
                addrs = ifam->ifam_addrs;
                q = (char *)(ifam + 1);
                break;
        case RTM_IFINFO:
                ifm = (struct if_msghdr *)p;
                addrs = ifm->ifm_addrs;
                q = (char *)(ifm + 1);
                break;
        default:
                rtm = (struct rt_msghdr *)p;
                addrs = rtm->rtm_addrs;
                q = (char *)(p + rtm->rtm_hdrlen);
                if (rtm->rtm_pid == pid) {
#if 0
                        log_debug("rtmsg looped back to me, ignored");
#endif
                        return;
                }
                break;
        }
        memset(&rta, 0, sizeof(rta));
        for (i = 0; i < RTAX_MAX; i++) {
                if (addrs & (1 << i)) {
                        rta[i] = (struct sockaddr_in6 *)q;
                        q += ROUNDUP(rta[i]->sin6_len);
                }
        }

        log_debug("rtsock: %s (addrs=%x)",
            rttypes((struct rt_msghdr *)p), addrs);
        if (dflag >= 2) {
                for (i = 0;
                     i < ((struct rt_msghdr *)p)->rtm_msglen;
                     i++) {
                        log_enqueue("%02x ", p[i] & 0xff);
                        if (i % 16 == 15)
                                log_debug("");
                }
                log_debug("");
        }
        /*
         * 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 *)p)->rtm_type) {
        case RTM_NEWADDR:
        case RTM_IFINFO:
                iface++;
                return;
        case RTM_ADD:
                rtable++;
                return;
        case RTM_MISS:
        case RTM_RESOLVE:
        case RTM_GET:
                /* nothing to be done here */
                log_debug("\tnothing to be done, ignored");
                return;
        }

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

        /* hard ones */
        switch (((struct rt_msghdr *)p)->rtm_type) {
        case RTM_NEWADDR:
        case RTM_IFINFO:
        case RTM_ADD:
        case RTM_MISS:
        case RTM_RESOLVE:
        case RTM_GET:
                /* should already be handled */
                fatalx("rtrecv: never reach here");
                /*NOTREACHED*/
        case RTM_DELETE:
                if (!rta[RTAX_DST] || !rta[RTAX_GATEWAY]) {
                        log_debug("\tsome of dst/gw/netmask are "
                            "unavailable, ignored");
                        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]) {
                        log_debug("\tsome of dst/gw/netmask are "
                            "unavailable, ignored");
                        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:
                log_debug("\tnot supported yet, ignored");
                break;
        case RTM_DELADDR:
                if (!rta[RTAX_NETMASK] || !rta[RTAX_IFA]) {
                        log_debug("\tno netmask or ifa given, ignored");
                        break;
                }
                if (ifam->ifam_index < nindex2ifc)
                        ifcp = index2ifc[ifam->ifam_index];
                else
                        ifcp = NULL;
                if (!ifcp) {
                        log_debug("\tinvalid ifam_index %d, ignored",
                            ifam->ifam_index);
                        break;
                }
                if (!rt_deladdr(ifcp, rta[RTAX_IFA], rta[RTAX_NETMASK]))
                        iface++;
                break;
        }

        if (iface) {
                log_debug("rtsock: reconfigure interfaces, refresh interface routes");
                ifconfig();
                for (ifcp = ifc; ifcp; ifcp = ifcp->ifc_next)
                        if (ifcp->ifc_cflags & IFC_CHANGED) {
                                if (ifrt(ifcp, 1)) {
                                        for (ic = ifc; ic; ic = ic->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 */
                                        for (rrt = riprt; rrt; rrt = rrt->rrt_next)
                                                rrt->rrt_rflags &= ~RRTF_CHANGED;
                                }
                                ifcp->ifc_cflags &= ~IFC_CHANGED;
                        }
        }
        if (rtable) {
                log_debug("rtsock: read routing table again");
                krtread(1);
        }
}

/*
 * remove specified route from the internal routing table.
 */
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) {
                log_debug("\tother AF, ignored");
                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)) {
                log_debug("\taddress %s not interesting, ignored",
                        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;
                log_debug("\t%s is a interface route, guessing prefixlen",
                        inet6_n2p(dst));
                longest = NULL;
                for (rrt = riprt; rrt; rrt = rrt->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) {
                        log_debug("\tno matching interface route found");
                        return -1;
                }
                gw = &in6addr_loopback;
                prefix = rrt->rrt_info.rip6_plen;
        } else {
                log_debug("\tunsupported af: (gw=%d)", sgw->sin6_family);
                return -1;
        }

        log_enqueue("\tdeleting %s/%d ", inet6_n2p(dst), prefix);
        log_debug("gw %s", 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*/
        log_debug("\tfind route %s/%d", inet6_n2p(&ni6.rip6_dest),
                ni6.rip6_plen);
        if (!rrt && (rrt = rtsearch(&ni6, NULL)) == NULL) {
                log_debug("\tno route found");
                return -1;
        }
#if 0
        if ((rrt->rrt_flags & RTF_STATIC) == 0) {
                log_debug("\tyou can delete static routes only");
        } else
#endif
        if (!IN6_ARE_ADDR_EQUAL(&rrt->rrt_gw, gw)) {
                log_enqueue("\tgw mismatch: %s <-> ",
                        inet6_n2p(&rrt->rrt_gw));
                log_debug("%s", inet6_n2p(gw));
        } else {
                log_debug("\troute found, age it");
                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.
 */
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 *ifa = NULL;
        struct netinfo6 ni6;
        struct riprt *rrt = NULL;
        time_t t_lifetime;
        int updated = 0;

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

        log_debug("\tdeleting %s/%d from %s",
                inet6_n2p(addr), prefix, ifcp->ifc_name);
        ifa = ifa_match(ifcp, addr, prefix);
        if (!ifa) {
                log_debug("\tno matching ifa found for %s/%d on %s",
                        inet6_n2p(addr), prefix, ifcp->ifc_name);
                return -1;
        }
        if (ifa->ifa_conf != ifcp) {
                log_debug("\taddress table corrupt: back pointer does not match "
                        "(%s != %s)",
                        ifcp->ifc_name, ifa->ifa_conf->ifc_name);
                return -1;
        }
        /* remove ifa from interface */
        if (ifcp->ifc_addr == ifa)
                ifcp->ifc_addr = ifa->ifa_next;
        else {
                struct ifac *p;
                for (p = ifcp->ifc_addr; p; p = p->ifa_next) {
                        if (p->ifa_next == ifa) {
                                p->ifa_next = ifa->ifa_next;
                                break;
                        }
                }
        }
        ifa->ifa_next = NULL;
        ifa->ifa_conf = NULL;
        t_lifetime = time(NULL) - RIP_LIFETIME;
        /* age route for interface address */
        memset(&ni6, 0, sizeof(ni6));
        ni6.rip6_dest = ifa->ifa_addr;
        ni6.rip6_plen = ifa->ifa_plen;
        applyplen(&ni6.rip6_dest, ni6.rip6_plen);
        log_debug("\tfind interface route %s/%d on %d",
                inet6_n2p(&ni6.rip6_dest), ni6.rip6_plen, ifcp->ifc_index);
        if ((rrt = rtsearch(&ni6, NULL)) != 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))) {
                        log_debug("\troute found, age it");
                        if (rrt->rrt_t == 0 || rrt->rrt_t > t_lifetime) {
                                rrt->rrt_t = t_lifetime;
                                rrt->rrt_info.rip6_metric = HOPCNT_INFINITY6;
                        }
                        updated++;
                } else {
                        log_debug("\tnon-interface route found: %s/%d on %d",
                                inet6_n2p(&rrt->rrt_info.rip6_dest),
                                rrt->rrt_info.rip6_plen,
                                rrt->rrt_index);
                }
        } else
                log_debug("\tno interface route found");
        /* age route for p2p destination */
        if (ifcp->ifc_flags & IFF_POINTOPOINT) {
                memset(&ni6, 0, sizeof(ni6));
                ni6.rip6_dest = ifa->ifa_raddr;
                ni6.rip6_plen = 128;
                applyplen(&ni6.rip6_dest, ni6.rip6_plen);       /*to be sure*/
                log_debug("\tfind p2p route %s/%d on %d",
                        inet6_n2p(&ni6.rip6_dest), ni6.rip6_plen,
                        ifcp->ifc_index);
                if ((rrt = rtsearch(&ni6, NULL)) != NULL) {
                        if (rrt->rrt_index == ifcp->ifc_index &&
                            IN6_ARE_ADDR_EQUAL(&rrt->rrt_gw, &ifa->ifa_addr)) {
                                log_debug("\troute found, age it");
                                if (rrt->rrt_t == 0 || rrt->rrt_t > t_lifetime) {
                                        rrt->rrt_t = t_lifetime;
                                        rrt->rrt_info.rip6_metric =
                                            HOPCNT_INFINITY6;
                                        updated++;
                                }
                        } else {
                                log_debug("\tnon-p2p route found: %s/%d on %d",
                                        inet6_n2p(&rrt->rrt_info.rip6_dest),
                                        rrt->rrt_info.rip6_plen,
                                        rrt->rrt_index);
                        }
                } else
                        log_debug("\tno p2p route found");
        }
        return updated ? 0 : -1;
}

/*
 * Get each interface address and put those interface routes to the route
 * list.
 */
int
ifrt(struct ifc *ifcp, int again)
{
        struct ifac *ifa;
        struct riprt *rrt = NULL, *search_rrt, *prev_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;
        }

        for (ifa = ifcp->ifc_addr; ifa; ifa = ifa->ifa_next) {
                if (IN6_IS_ADDR_LINKLOCAL(&ifa->ifa_addr)) {
#if 0
                        log_debug("route: %s on %s: "
                            "skip linklocal interface address",
                            inet6_n2p(&ifa->ifa_addr), ifcp->ifc_name);
#endif
                        continue;
                }
                if (IN6_IS_ADDR_UNSPECIFIED(&ifa->ifa_addr)) {
#if 0
                        log_debug("route: %s: skip unspec interface address",
                            ifcp->ifc_name);
#endif
                        continue;
                }
                if (IN6_IS_ADDR_LOOPBACK(&ifa->ifa_addr)) {
#if 0
                        log_debug("route: %s: skip loopback address",
                            ifcp->ifc_name);
#endif
                        continue;
                }
                if (ifcp->ifc_flags & IFF_UP) {
                        if ((rrt = calloc(1, sizeof(struct riprt))) == NULL)
                                fatal("calloc: struct riprt");
                        rrt->rrt_index = ifcp->ifc_index;
                        rrt->rrt_t = 0; /* don't age */
                        rrt->rrt_info.rip6_dest = ifa->ifa_addr;
                        rrt->rrt_info.rip6_tag = htons(routetag & 0xffff);
                        rrt->rrt_info.rip6_metric = 1 + ifcp->ifc_metric;
                        rrt->rrt_info.rip6_plen = ifa->ifa_plen;
                        if (ifa->ifa_plen == 128)
                                rrt->rrt_flags = RTF_HOST;
                        else
                                rrt->rrt_flags = RTF_CLONING;
                        rrt->rrt_rflags |= RRTF_CHANGED;
                        applyplen(&rrt->rrt_info.rip6_dest, ifa->ifa_plen);
                        memset(&rrt->rrt_gw, 0, sizeof(struct in6_addr));
                        rrt->rrt_gw = ifa->ifa_addr;
                        np = &rrt->rrt_info;
                        search_rrt = rtsearch(np, &prev_rrt);
                        if (search_rrt != NULL) {
                                if (search_rrt->rrt_info.rip6_metric <=
                                    rrt->rrt_info.rip6_metric) {
                                        /* Already have better route */
                                        if (!again) {
                                                log_debug("route: %s/%d: "
                                                    "already registered (%s)",
                                                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                                                    ifcp->ifc_name);
                                        }
                                        goto next;
                                }

                                if (prev_rrt)
                                        prev_rrt->rrt_next = rrt->rrt_next;
                                else
                                        riprt = rrt->rrt_next;
                                delroute(&rrt->rrt_info, &rrt->rrt_gw);
                        }
                        /* Attach the route to the list */
                        log_debug("route: %s/%d: register route (%s)",
                            inet6_n2p(&np->rip6_dest), np->rip6_plen,
                            ifcp->ifc_name);
                        rrt->rrt_next = riprt;
                        riprt = rrt;
                        addroute(rrt, &rrt->rrt_gw, ifcp);
                        rrt = NULL;
                        sendrequest(ifcp);
                        ripsend(ifcp, &ifcp->ifc_ripsin, 0);
                        need_trigger = 1;
                } else {
                        for (loop_rrt = riprt; loop_rrt; loop_rrt = loop_rrt->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:
                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.
 */
void
ifrt_p2p(struct ifc *ifcp, int again)
{
        struct ifac *ifa;
        struct riprt *rrt, *orrt, *prevrrt;
        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;

        for (ifa = ifcp->ifc_addr; ifa; ifa = ifa->ifa_next) {
                addr = ifa->ifa_addr;
                dest = ifa->ifa_raddr;
                applyplen(&addr, ifa->ifa_plen);
                applyplen(&dest, ifa->ifa_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(&ifa->ifa_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 = calloc(1, sizeof(struct riprt))) == NULL) {
                                fatal("calloc: struct riprt");
                                /*NOTREACHED*/
                        }
                        rrt->rrt_index = ifcp->ifc_index;
                        rrt->rrt_t = 0; /* don't age */
                        switch (i) {
                        case P2PADVERT_NETWORK:
                                rrt->rrt_info.rip6_dest = ifa->ifa_addr;
                                rrt->rrt_info.rip6_plen = ifa->ifa_plen;
                                applyplen(&rrt->rrt_info.rip6_dest,
                                    ifa->ifa_plen);
                                category = "network";
                                break;
                        case P2PADVERT_ADDR:
                                rrt->rrt_info.rip6_dest = ifa->ifa_addr;
                                rrt->rrt_info.rip6_plen = 128;
                                rrt->rrt_gw = in6addr_loopback;
                                category = "addr";
                                break;
                        case P2PADVERT_DEST:
                                rrt->rrt_info.rip6_dest = ifa->ifa_raddr;
                                rrt->rrt_info.rip6_plen = 128;
                                rrt->rrt_gw = ifa->ifa_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
                                log_debug("route: %s: skip unspec/linklocal "
                                    "(%s on %s)", 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, &prevrrt);
                        if (!orrt) {
                                /* Attach the route to the list */
                                log_debug("route: %s/%d: register route "
                                    "(%s on %s%s)",
                                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                                    category, ifcp->ifc_name, noadv);
                                rrt->rrt_next = riprt;
                                riprt = rrt;
                        } else if (rrt->rrt_index != orrt->rrt_index ||
                            rrt->rrt_info.rip6_metric != orrt->rrt_info.rip6_metric) {
                                /* swap route */
                                rrt->rrt_next = orrt->rrt_next;
                                if (prevrrt)
                                        prevrrt->rrt_next = rrt;
                                else
                                        riprt = rrt;
                                free(orrt);

                                log_debug("route: %s/%d: update (%s on %s%s)",
                                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                                    category, ifcp->ifc_name, noadv);
                        } else {
                                /* Already found */
                                if (!again) {
                                        log_debug("route: %s/%d: "
                                            "already registered (%s on %s%s)",
                                            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
}

int
getifmtu(int ifindex)
{
        int     mib[6];
        char    *buf = NULL;
        size_t  needed;
        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;
        while (1) {
                if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1)
                        fatal("sysctl estimate NET_RT_IFLIST");
                if (needed == 0)
                        break;
                if ((buf = realloc(buf, needed)) == NULL)
                        fatal(NULL);
                if (sysctl(mib, 6, buf, &needed, NULL, 0) == -1) {
                        if (errno == ENOMEM)
                                continue;
                        fatal("sysctl NET_RT_IFLIST");
                }
                break;
        }
        ifm = (struct if_msghdr *)buf;
        mtu = ifm->ifm_data.ifi_mtu;
        free(buf);
        return mtu;
}

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("REDIRECT", RTM_REDIRECT);
        RTTYPE("MISS", RTM_MISS);
        RTTYPE("RESOLVE", RTM_RESOLVE);
        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;
}

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);
        RTFLAG("m", RTF_MULTICAST);
        RTFLAG("C", RTF_CLONING);
        RTFLAG("c", RTF_CLONED);
        RTFLAG("L", RTF_LLINFO);
        RTFLAG("S", RTF_STATIC);
        RTFLAG("B", RTF_BLACKHOLE);
        RTFLAG("3", RTF_PROTO3);
        RTFLAG("2", RTF_PROTO2);
        RTFLAG("1", RTF_PROTO1);
        RTFLAG("b", RTF_BROADCAST);
#undef RTFLAG
        return buf;
}

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);
        IFFLAG("STATICARP", IFF_STATICARP);
        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;
}

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 {
                retry++;
                free(buf);
                buf = NULL;
                errmsg = NULL;
                if (sysctl(mib, 6, NULL, &msize, NULL, 0) == -1) {
                        errmsg = "sysctl estimate";
                        continue;
                }
                if ((buf = malloc(msize)) == NULL) {
                        errmsg = "malloc";
                        continue;
                }
                if (sysctl(mib, 6, buf, &msize, NULL, 0) == -1) {
                        errmsg = "sysctl NET_RT_DUMP";
                        continue;
                }
        } while (retry < 5 && errmsg != NULL);
        if (errmsg) {
                fatal(errmsg);
                /*NOTREACHED*/
        } else if (1 < retry)
                log_info("NET_RT_DUMP %d retries", retry);

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

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

        sin6_dst = sin6_gw = sin6_mask = sin6_ifp = 0;
        if ((rtm->rtm_flags & RTF_UP) == 0 || rtm->rtm_flags &
                (RTF_CLONING|RTF_LLINFO|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
        /*
         * do not look at dynamic routes.
         * netbsd/openbsd cloned routes have UGHD.
         */
        if (rtm->rtm_flags & RTF_DYNAMIC)
                return;
        rtmp = (char *)((char *)rtm + rtm->rtm_hdrlen);
        /* Destination */
        if ((rtm->rtm_addrs & RTA_DST) == 0)
                return;         /* ignore routes without destination address */
        sin6_dst = (struct sockaddr_in6 *)rtmp;
        rtmp += ROUNDUP(sin6_dst->sin6_len);
        if (rtm->rtm_addrs & RTA_GATEWAY) {
                sin6_gw = (struct sockaddr_in6 *)rtmp;
                rtmp += ROUNDUP(sin6_gw->sin6_len);
        }
        if (rtm->rtm_addrs & RTA_NETMASK) {
                sin6_mask = (struct sockaddr_in6 *)rtmp;
                rtmp += ROUNDUP(sin6_mask->sin6_len);
        }
        if (rtm->rtm_addrs & RTA_IFP) {
                sin6_ifp = (struct sockaddr_in6 *)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 = calloc(1, sizeof(struct riprt))) == NULL) {
                fatal("calloc: struct riprt");
                /*NOTREACHED*/
        }
        np = &rrt->rrt_info;
        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 & (RTF_HOST|RTF_GATEWAY)) == RTF_HOST)
                rrt->rrt_t = 0; /* Don't age non-gateway host routes */
        np->rip6_tag = 0;
        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, NULL);
        if (orrt && orrt->rrt_info.rip6_metric != HOPCNT_INFINITY6) {
                /* Already found */
                if (!again) {
                        log_debug("route: %s/%d flags %s: already registered",
                                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));
        }
        log_enqueue("route: %s/%d flags %s",
                inet6_n2p(&np->rip6_dest), np->rip6_plen, rtflags(rtm));
        log_enqueue(" gw %s", inet6_n2p(&rrt->rrt_gw));

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

        /* Check gateway */
        if (!IN6_IS_ADDR_LINKLOCAL(&rrt->rrt_gw) &&
            !IN6_IS_ADDR_LOOPBACK(&rrt->rrt_gw)) {
                log_warnx("***** Gateway %s is not a link-local address.",
                        inet6_n2p(&rrt->rrt_gw));
                log_warnx("*****     dest(%s) if(%s) -- Not optimized.",
                        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 */
                rrt->rrt_next = orrt->rrt_next;
                *orrt = *rrt;
                log_debug("route: %s/%d flags %s: replace new route",
                    inet6_n2p(&np->rip6_dest), np->rip6_plen,
                    rtflags(rtm));
                free(rrt);
        } else {
                rrt->rrt_next = riprt;
                riprt = rrt;
        }
}

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));
        if (uflag)
                log_info("RTADD: %s/%d gw %s [%d] ifa %s",
                    inet6_n2p(&np->rip6_dest), np->rip6_plen, buf1,
                    np->rip6_metric - 1, buf2);
        else
                log_debug("RTADD: %s/%d gw %s [%d] ifa %s",
                    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 *)buf;
        rtm->rtm_type = RTM_ADD;
        rtm->rtm_version = RTM_VERSION;
        rtm->rtm_seq = ++seq;
        rtm->rtm_flags = rrt->rrt_flags;
        rtm->rtm_addrs = RTA_DST | RTA_GATEWAY | RTA_NETMASK;
        rtm->rtm_inits = RTV_HOPCOUNT;
        sin6 = (struct sockaddr_in6 *)&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 *)((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 *)((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 *)((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) {
                log_warnx("RTADD: Route already exists %s/%d gw %s",
                    inet6_n2p(&np->rip6_dest), np->rip6_plen, buf1);
        } else {
                log_warnx("RTADD: Can not write to rtsock (addroute): %s",
                    strerror(errno));
        }
        return -1;
}

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));
        if (uflag)
                log_info("RTDEL: %s/%d gw %s", inet6_n2p(&np->rip6_dest),
                    np->rip6_plen, buf2);
        else
                log_debug("RTDEL: %s/%d gw %s", inet6_n2p(&np->rip6_dest),
                    np->rip6_plen, buf2);

        if (nflag)
                return 0;

        memset(buf, 0, sizeof(buf));
        rtm = (struct rt_msghdr *)buf;
        rtm->rtm_type = RTM_DELETE;
        rtm->rtm_version = RTM_VERSION;
        rtm->rtm_seq = ++seq;
        rtm->rtm_flags = RTF_UP | RTF_GATEWAY;
        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 *)&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 *)((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 *)((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 *)((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) {
                log_warnx("RTDEL: Route does not exist: %s/%d gw %s",
                    inet6_n2p(&np->rip6_dest), np->rip6_plen, buf2);
        } else {
                log_warnx("RTDEL: Can not write to rtsock (delroute): %s",
                    strerror(errno));
        }
        return -1;
}

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

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

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

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

void
ifrtdump(int sig)
{

        ifdump(sig);
        rtdump(sig);
}

void
ifdump(int sig)
{
        struct ifc *ifcp;
        int i;

        log_info("%s: Interface Table Dump", hms());
        log_info("  Number of interfaces: %d", nifc);
        for (i = 0; i < 2; i++) {
                log_info("  %sadvertising interfaces:", i ? "non-" : "");
                for (ifcp = ifc; ifcp; ifcp = ifcp->ifc_next) {
                        if (i == 0) {
                                if ((ifcp->ifc_flags & IFF_UP) == 0)
                                        continue;
                                if (iff_find(ifcp, 'N') != NULL)
                                        continue;
                        } else {
                                if (ifcp->ifc_flags & IFF_UP)
                                        continue;
                        }
                        ifdump0(ifcp);
                }
        }
        log_info("");
}

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

        log_info("    %s: index(%d) flags(%s) addr(%s) mtu(%d) metric(%d)",
                ifcp->ifc_name, ifcp->ifc_index, ifflags(ifcp->ifc_flags),
                inet6_n2p(&ifcp->ifc_mylladdr),
                ifcp->ifc_mtu, ifcp->ifc_metric);
        for (ifa = ifcp->ifc_addr; ifa; ifa = ifa->ifa_next) {
                if (ifcp->ifc_flags & IFF_POINTOPOINT) {
                        inet_ntop(AF_INET6, (void *)&ifa->ifa_raddr,
                                buf, sizeof(buf));
                        log_info("\t%s/%d -- %s",
                                inet6_n2p(&ifa->ifa_addr),
                                ifa->ifa_plen, buf);
                } else {
                        log_info("\t%s/%d",
                                inet6_n2p(&ifa->ifa_addr),
                                ifa->ifa_plen);
                }
        }
        if (ifcp->ifc_filter) {
                log_enqueue("\tFilter:");
                for (iffp = ifcp->ifc_filter; iffp; iffp = iffp->iff_next) {
                        addr = 0;
                        switch (iffp->iff_type) {
                        case 'A':
                                ft = "Aggregate"; addr++; break;
                        case 'N':
                                ft = "No-use"; break;
                        case 'O':
                                ft = "Advertise-only"; addr++; break;
                        case 'T':
                                ft = "Default-only"; break;
                        case 'L':
                                ft = "Listen-only"; addr++; break;
                        default:
                                snprintf(buf, sizeof(buf), "Unknown-%c", iffp->iff_type);
                                ft = buf;
                                addr++;
                                break;
                        }
                        log_enqueue(" %s", ft);
                        if (addr) {
                                log_enqueue("(%s/%d)",
                                    inet6_n2p(&iffp->iff_addr), iffp->iff_plen);
                        }
                }
                log_info("");
        }
}

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

        t = time(NULL);
        log_info("%s: Routing Table Dump", hms());
        for (rrt = riprt; rrt; rrt = rrt->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));
                log_enqueue("    %s/%d if(%d:%s) gw(%s) [%d] age(%lld)",
                        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 long)age);
                if (rrt->rrt_info.rip6_tag) {
                        log_enqueue(" tag(0x%04x)",
                                ntohs(rrt->rrt_info.rip6_tag) & 0xffff);
                }
                if (rrt->rrt_rflags & RRTF_NH_NOT_LLADDR)
                        log_enqueue(" NOT-LL");
                if (rrt->rrt_rflags & RRTF_NOADVERTISE)
                        log_enqueue(" NO-ADV");
                log_info("");
        }
}

/*
 * 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)
 */
void
filterconfig(void)
{
        int i;
        char *p, *ap, *iflp, *ifname, *ep;
        struct iff ftmp, *iff_obj;
        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;
                ifcp = NULL;
                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) {
                        log_warnx("no prefixlen specified for '%s'", ap);
                        fatalx("exiting");
                        /*NOTREACHED*/
                }
                *p++ = '\0';
                if (inet_pton(AF_INET6, ap, &ftmp.iff_addr) != 1) {
                        log_warnx("invalid prefix specified for '%s'", ap);
                        fatalx("exiting");
                        /*NOTREACHED*/
                }
                errno = 0;
                ep = NULL;
                plen = strtoul(p, &ep, 10);
                if (errno || !*p || *ep || plen > sizeof(ftmp.iff_addr) * 8) {
                        log_warnx("invalid prefix length specified for '%s'", ap);
                        fatalx("exiting");
                        /*NOTREACHED*/
                }
                ftmp.iff_plen = plen;
                ftmp.iff_next = NULL;
                applyplen(&ftmp.iff_addr, ftmp.iff_plen);
ifonly:
                ftmp.iff_type = filtertype[i];
                if (iflp == NULL || *iflp == '\0') {
                        log_warnx("no interface specified for '%s'", ap);
                        fatal("exiting");
                        /*NOTREACHED*/
                }
                /* parse the interface listing portion */
                while (iflp) {
                        ifname = iflp;
                        if ((iflp = strchr(iflp, ',')) != NULL)
                                *iflp++ = '\0';
                        ifcp = ifc_find(ifname);
                        if (ifcp == NULL) {
                                log_warnx("no interface %s exists", ifname);
                                fatalx("exiting");
                                /*NOTREACHED*/
                        }
                        iff_obj = malloc(sizeof(struct iff));
                        if (iff_obj == NULL) {
                                fatal("malloc of iff_obj");
                                /*NOTREACHED*/
                        }
                        memcpy((void *)iff_obj, (void *)&ftmp,
                            sizeof(struct iff));
                        /* link it to the interface filter */
                        iff_obj->iff_next = ifcp->ifc_filter;
                        ifcp->ifc_filter = iff_obj;
                }

                /*
                 * -A: aggregate configuration.
                 */
                if (filtertype[i] != 'A')
                        continue;
                /* put the aggregate to the kernel routing table */
                rrt = calloc(1, sizeof(struct riprt));
                if (rrt == NULL) {
                        fatal("calloc: rrt");
                        /*NOTREACHED*/
                }
                rrt->rrt_info.rip6_dest = ftmp.iff_addr;
                rrt->rrt_info.rip6_plen = ftmp.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 */
                rrt->rrt_next = riprt;
                riprt = rrt;
                log_debug("Aggregate: %s/%d for %s",
                        inet6_n2p(&ftmp.iff_addr), ftmp.iff_plen,
                        ifcp->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.
 */
struct ifac *
ifa_match(const struct ifc *ifcp, const struct in6_addr *ia, int plen)
{
        struct ifac *ifa;

        for (ifa = ifcp->ifc_addr; ifa; ifa = ifa->ifa_next) {
                if (IN6_ARE_ADDR_EQUAL(&ifa->ifa_addr, ia) &&
                    ifa->ifa_plen == plen)
                        break;
        }
        return ifa;
}

/*
 * 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.
 */
struct riprt *
rtsearch(struct netinfo6 *np, struct riprt **prev_rrt)
{
        struct  riprt   *rrt;

        if (prev_rrt)
                *prev_rrt = NULL;
        for (rrt = riprt; rrt; rrt = rrt->rrt_next) {
                if (rrt->rrt_info.rip6_plen == np->rip6_plen &&
                    IN6_ARE_ADDR_EQUAL(&rrt->rrt_info.rip6_dest,
                                       &np->rip6_dest))
                        return rrt;
                if (prev_rrt)
                        *prev_rrt = rrt;
        }
        if (prev_rrt)
                *prev_rrt = NULL;
        return 0;
}

int
sin6mask2len(const struct sockaddr_in6 *sin6)
{

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

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;
}

void
applyplen(struct in6_addr *ia, int plen)
{
        static const u_char plent[8] = {
                0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe
        };
        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;
        }
}

struct in6_addr *
plen2mask(int n)
{
        static const int pl2m[9] = {
                0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
        };
        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;
}

char *
xstrdup(const char *p)
{
        char *q;

        q = strdup(p);
        if (q == NULL) {
                fatal("strdup");
                /*NOTREACHED*/
        }
        return q;
}

const 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 */

int
ripinterval(int timer)
{
        double r = arc4random();
        int interval;

        interval = (int)(timer + timer * RIPRANDDEV * (r / UINT32_MAX - 0.5));
        nextalarm = time(NULL) + interval;
        return interval;
}

time_t
ripsuptrig(void)
{
        time_t t;

        double r = arc4random();
        t  = (int)(RIP_TRIG_INT6_MIN + 
                (RIP_TRIG_INT6_MAX - RIP_TRIG_INT6_MIN) * (r / UINT32_MAX));
        sup_trig_update = time(NULL) + t;
        return t;
}

unsigned int
if_maxindex(void)
{
        struct if_nameindex *p, *p0;
        unsigned int max = 0;

        p0 = if_nameindex();
        for (p = p0; p && p->if_index && p->if_name; p++) {
                if (max < p->if_index)
                        max = p->if_index;
        }
        if_freenameindex(p0);
        return max;
}

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

        for (ifcp = ifc; ifcp; ifcp = ifcp->ifc_next) {
                if (strcmp(name, ifcp->ifc_name) == 0)
                        return ifcp;
        }
        return (struct ifc *)NULL;
}

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

        for (iffp = ifcp->ifc_filter; iffp; iffp = iffp->iff_next) {
                if (iffp->iff_type == type)
                        return iffp;
        }
        return NULL;
}

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

        if (!index2ifc) {
                nindex2ifc = 5; /*initial guess*/
                index2ifc = calloc(nindex2ifc, sizeof(*index2ifc));
                if (index2ifc == NULL) {
                        fatal("calloc");
                        /*NOTREACHED*/
                }
        }
        n = nindex2ifc;
        while (nindex2ifc <= idx)
                nindex2ifc *= 2;
        if (n != nindex2ifc) {
                p = reallocarray(index2ifc, nindex2ifc, sizeof(*index2ifc));
                if (p == NULL) {
                        fatal("reallocarray");
                        /*NOTREACHED*/
                }
                memset(p + n, 0, (nindex2ifc - n) * sizeof(*index2ifc));
                index2ifc = p;
        }
        index2ifc[idx] = ifcp;
}