/*	$OpenBSD: kroute.c,v 1.5 2007/10/17 20:54:41 claudio Exp $ */

/*
 * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/tree.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "ospf6d.h"
#include "log.h"

struct {
	u_int32_t		rtseq;
	pid_t			pid;
	int			fib_sync;
	int			fd;
	struct event		ev;
} kr_state;

struct kroute_node {
	RB_ENTRY(kroute_node)	 entry;
	struct kroute		 r;
	struct kroute_node	*next;
};

struct kif_node {
	RB_ENTRY(kif_node)	 entry;
	TAILQ_HEAD(, kif_addr)	 addrs;
	struct kif		 k;
};

void	kr_redist_remove(struct kroute_node *, struct kroute_node *);
int	kr_redist_eval(struct kroute *, struct rroute *);
void	kr_redistribute(struct kroute_node *);
int	kroute_compare(struct kroute_node *, struct kroute_node *);
int	kif_compare(struct kif_node *, struct kif_node *);

struct kroute_node	*kroute_find(const struct in6_addr *, u_int8_t);
struct kroute_node	*kroute_matchgw(struct kroute_node *,
			    struct in6_addr *);
int			 kroute_insert(struct kroute_node *);
int			 kroute_remove(struct kroute_node *);
void			 kroute_clear(void);

struct kif_node		*kif_find(u_short);
struct kif_node		*kif_insert(u_short);
int			 kif_remove(struct kif_node *);
void			 kif_clear(void);
struct kif		*kif_update(u_short, int, struct if_data *,
			    struct sockaddr_dl *);
int			 kif_validate(u_short);

struct kroute_node	*kroute_match(struct in6_addr *);

int		protect_lo(void);
void		get_rtaddrs(int, struct sockaddr *, struct sockaddr **);
void		if_change(u_short, int, struct if_data *);
void		if_newaddr(u_short, struct sockaddr_in6 *,
		    struct sockaddr_in6 *, struct sockaddr_in6 *);
void		if_announce(void *);

int		send_rtmsg(int, int, struct kroute *);
int		dispatch_rtmsg(void);
int		fetchtable(void);
int		fetchifs(u_short);

RB_HEAD(kroute_tree, kroute_node)	krt;
RB_PROTOTYPE(kroute_tree, kroute_node, entry, kroute_compare)
RB_GENERATE(kroute_tree, kroute_node, entry, kroute_compare)

RB_HEAD(kif_tree, kif_node)		kit;
RB_PROTOTYPE(kif_tree, kif_node, entry, kif_compare)
RB_GENERATE(kif_tree, kif_node, entry, kif_compare)

int
kif_init(void)
{
	RB_INIT(&kit);

	if (fetchifs(0) == -1)
		return (-1);

	return (0);
}

int
kr_init(int fs)
{
	int		opt = 0, rcvbuf, default_rcvbuf;
	socklen_t	optlen;

	kr_state.fib_sync = fs;

	if ((kr_state.fd = socket(AF_ROUTE, SOCK_RAW, 0)) == -1) {
		log_warn("kr_init: socket");
		return (-1);
	}

	/* not interested in my own messages */
	if (setsockopt(kr_state.fd, SOL_SOCKET, SO_USELOOPBACK,
	    &opt, sizeof(opt)) == -1)
		log_warn("kr_init: setsockopt");	/* not fatal */

	/* grow receive buffer, don't wanna miss messages */
	optlen = sizeof(default_rcvbuf);
	if (getsockopt(kr_state.fd, SOL_SOCKET, SO_RCVBUF,
	    &default_rcvbuf, &optlen) == -1)
		log_warn("kr_init getsockopt SOL_SOCKET SO_RCVBUF");
	else
		for (rcvbuf = MAX_RTSOCK_BUF;
		    rcvbuf > default_rcvbuf &&
		    setsockopt(kr_state.fd, SOL_SOCKET, SO_RCVBUF,
		    &rcvbuf, sizeof(rcvbuf)) == -1 && errno == ENOBUFS;
		    rcvbuf /= 2)
			;	/* nothing */

	kr_state.pid = getpid();
	kr_state.rtseq = 1;

	RB_INIT(&krt);

	if (fetchtable() == -1)
		return (-1);

	if (protect_lo() == -1)
		return (-1);

	event_set(&kr_state.ev, kr_state.fd, EV_READ | EV_PERSIST,
	    kr_dispatch_msg, NULL);
	event_add(&kr_state.ev, NULL);

	return (0);
}

int
kr_change(struct kroute *kroute)
{
	struct kroute_node	*kr;
	int			 action = RTM_ADD;

	kroute->rtlabel = rtlabel_tag2id(kroute->ext_tag);

	if ((kr = kroute_find(&kroute->prefix, kroute->prefixlen)) !=
	    NULL) {
		if (!(kr->r.flags & F_KERNEL))
			action = RTM_CHANGE;
		else {	/* a non-ospf route already exists. not a problem */
			if (!(kr->r.flags & F_BGPD_INSERTED)) {
				do {
					kr->r.flags |= F_OSPFD_INSERTED;
					kr = kr->next;
				} while (kr);
				return (0);
			}
			/*
			 * XXX as long as there is no multipath support in
			 * bgpd this is safe else we end up in a bad situation.
			 */
			/*
			 * ospf route has higher pref
			 * - reset flags to the ospf ones
			 * - use RTM_CHANGE
			 * - zero out ifindex (this is no longer relevant)
			 */
			action = RTM_CHANGE;
			kr->r.flags = kroute->flags | F_OSPFD_INSERTED;
			kr->r.ifindex = 0;
			rtlabel_unref(kr->r.rtlabel);
			kr->r.ext_tag = kroute->ext_tag;
			kr->r.rtlabel = kroute->rtlabel;
		}
	}

	/* nexthop within 127/8 -> ignore silently */
	if (IN6_IS_ADDR_LOOPBACK(&kr->r.nexthop))
		return (0);

	/*
	 * Ingnore updates that did not change the route.
	 * Currently only the nexthop can change.
	 */
	if (kr && IN6_ARE_ADDR_EQUAL(&kr->r.nexthop, &kroute->nexthop))
		return (0);

	if (send_rtmsg(kr_state.fd, action, kroute) == -1)
		return (-1);

	if (action == RTM_ADD) {
		if ((kr = calloc(1, sizeof(struct kroute_node))) == NULL) {
			log_warn("kr_change");
			return (-1);
		}
		kr->r.prefix = kroute->prefix;
		kr->r.prefixlen = kroute->prefixlen;
		kr->r.nexthop = kroute->nexthop;
		kr->r.flags = kroute->flags | F_OSPFD_INSERTED;
		kr->r.ext_tag = kroute->ext_tag;
		kr->r.rtlabel = kroute->rtlabel;

		if (kroute_insert(kr) == -1)
			free(kr);
	} else
		kr->r.nexthop = kroute->nexthop;

	return (0);
}

int
kr_delete(struct kroute *kroute)
{
	struct kroute_node	*kr;

	if ((kr = kroute_find(&kroute->prefix, kroute->prefixlen)) ==
	    NULL)
		return (0);

	if (!(kr->r.flags & F_OSPFD_INSERTED))
		return (0);

	if (kr->r.flags & F_KERNEL) {
		/* remove F_OSPFD_INSERTED flag, route still exists in kernel */
		do {
			kr->r.flags &= ~F_OSPFD_INSERTED;
			kr = kr->next;
		} while (kr);
		return (0);
	}

	if (send_rtmsg(kr_state.fd, RTM_DELETE, kroute) == -1)
		return (-1);

	if (kroute_remove(kr) == -1)
		return (-1);

	return (0);
}

void
kr_shutdown(void)
{
	kr_fib_decouple();
	kroute_clear();
	kif_clear();
}

void
kr_fib_couple(void)
{
	struct kroute_node	*kr;

	if (kr_state.fib_sync == 1)	/* already coupled */
		return;

	kr_state.fib_sync = 1;

	RB_FOREACH(kr, kroute_tree, &krt)
		if (!(kr->r.flags & F_KERNEL))
			send_rtmsg(kr_state.fd, RTM_ADD, &kr->r);

	log_info("kernel routing table coupled");
}

void
kr_fib_decouple(void)
{
	struct kroute_node	*kr;

	if (kr_state.fib_sync == 0)	/* already decoupled */
		return;

	RB_FOREACH(kr, kroute_tree, &krt)
		if (!(kr->r.flags & F_KERNEL))
			send_rtmsg(kr_state.fd, RTM_DELETE, &kr->r);

	kr_state.fib_sync = 0;

	log_info("kernel routing table decoupled");
}

/* ARGSUSED */
void
kr_dispatch_msg(int fd, short event, void *bula)
{
	dispatch_rtmsg();
}

void
kr_show_route(struct imsg *imsg)
{
	struct kroute_node	*kr;
	struct kroute_node	*kn;
	int			 flags;
	struct in6_addr		 addr;

	switch (imsg->hdr.type) {
	case IMSG_CTL_KROUTE:
		if (imsg->hdr.len != IMSG_HEADER_SIZE + sizeof(flags)) {
			log_warnx("kr_show_route: wrong imsg len");
			return;
		}
		memcpy(&flags, imsg->data, sizeof(flags));
		RB_FOREACH(kr, kroute_tree, &krt)
			if (!flags || kr->r.flags & flags) {
				kn = kr;
				do {
					main_imsg_compose_ospfe(IMSG_CTL_KROUTE,
					    imsg->hdr.pid,
					    &kn->r, sizeof(kn->r));
				} while ((kn = kn->next) != NULL);
			}
		break;
	case IMSG_CTL_KROUTE_ADDR:
		if (imsg->hdr.len != IMSG_HEADER_SIZE +
		    sizeof(struct in6_addr)) {
			log_warnx("kr_show_route: wrong imsg len");
			return;
		}
		memcpy(&addr, imsg->data, sizeof(addr));
		kr = NULL;
		kr = kroute_match(&addr);
		if (kr != NULL)
			main_imsg_compose_ospfe(IMSG_CTL_KROUTE, imsg->hdr.pid,
			    &kr->r, sizeof(kr->r));
		break;
	default:
		log_debug("kr_show_route: error handling imsg");
		break;
	}

	main_imsg_compose_ospfe(IMSG_CTL_END, imsg->hdr.pid, NULL, 0);
}

void
kr_ifinfo(char *ifname, pid_t pid)
{
	struct kif_node	*kif;

	RB_FOREACH(kif, kif_tree, &kit)
		if (ifname == NULL || !strcmp(ifname, kif->k.ifname)) {
			main_imsg_compose_ospfe(IMSG_CTL_IFINFO,
			    pid, &kif->k, sizeof(kif->k));
		}

	main_imsg_compose_ospfe(IMSG_CTL_END, pid, NULL, 0);
}

void
kr_redist_remove(struct kroute_node *kh, struct kroute_node *kn)
{
	struct rroute	 rr;

	/* was the route redistributed? */
	if ((kn->r.flags & F_REDISTRIBUTED) == 0)
		return;

	/* remove redistributed flag */
	kn->r.flags &= ~F_REDISTRIBUTED;
	rr.kr = kn->r;
	rr.metric = DEFAULT_REDIST_METRIC;	/* some dummy value */

	/* probably inform the RDE (check if no other path is redistributed) */
	for (kn = kh; kn; kn = kn->next)
		if (kn->r.flags & F_REDISTRIBUTED)
			break;

	if (kn == NULL)
		main_imsg_compose_rde(IMSG_NETWORK_DEL, 0, &rr,
		    sizeof(struct rroute));
}

int
kr_redist_eval(struct kroute *kr, struct rroute *rr)
{
	u_int32_t	 metric = 0;

	/* Only non-ospfd routes are considered for redistribution. */
	if (!(kr->flags & F_KERNEL))
		goto dont_redistribute;

	/* Dynamic routes are not redistributable. */
	if (kr->flags & F_DYNAMIC)
		goto dont_redistribute;

	/* interface is not up and running so don't announce */
	if (kr->flags & F_DOWN)
		goto dont_redistribute;

	/*
	 * We consider unspecified, loopback, multicast, link- and site-local,
	 * IPv4 mapped and IPv4 compatible addresses as not redistributable.
	 */
	if (IN6_IS_ADDR_UNSPECIFIED(&kr->prefix) ||
	    IN6_IS_ADDR_LOOPBACK(&kr->prefix) ||
	    IN6_IS_ADDR_MULTICAST(&kr->prefix) ||
	    IN6_IS_ADDR_LINKLOCAL(&kr->prefix) ||
	    IN6_IS_ADDR_SITELOCAL(&kr->prefix) ||
	    IN6_IS_ADDR_V4MAPPED(&kr->prefix) ||
	    IN6_IS_ADDR_V4COMPAT(&kr->prefix))
		goto dont_redistribute;
	/*
	 * Consider networks with nexthop loopback as not redistributable.
	 */
	if (IN6_IS_ADDR_LOOPBACK(&kr->nexthop))
		goto dont_redistribute;

	/* Should we redistrubute this route? */
	if (!ospf_redistribute(kr, &metric))
		goto dont_redistribute;

	/* prefix should be redistributed */
	kr->flags |= F_REDISTRIBUTED;
	/*
	 * only on of all multipath routes can be redistributed so
	 * redistribute the best one.
	 */
	if (rr->metric > metric) {
		rr->kr = *kr;
		rr->metric = metric;
	}
	return (1);

dont_redistribute:
	/* was the route redistributed? */
	if ((kr->flags & F_REDISTRIBUTED) == 0)
		return (0);

	kr->flags &= ~F_REDISTRIBUTED;
	return (1);
}

void
kr_redistribute(struct kroute_node *kh)
{
	struct kroute_node	*kn;
	struct rroute		 rr;
	int			 redistribute = 0;

	bzero(&rr, sizeof(rr));
	rr.metric = UINT_MAX;
	for (kn = kh; kn; kn = kn->next)
		if (kr_redist_eval(&kn->r, &rr))
			redistribute = 1;

	if (!redistribute)
		return;

	if (rr.kr.flags & F_REDISTRIBUTED) {
		main_imsg_compose_rde(IMSG_NETWORK_ADD, 0, &rr,
		    sizeof(struct rroute));
	} else {
		rr.metric = DEFAULT_REDIST_METRIC;	/* some dummy value */
		rr.kr = kh->r;
		main_imsg_compose_rde(IMSG_NETWORK_DEL, 0, &rr,
		    sizeof(struct rroute));
	}
}

void
kr_reload(void)
{
	struct kroute_node	*kr, *kn;
	u_int32_t		 dummy;
	int			 r;

	RB_FOREACH(kr, kroute_tree, &krt) {
		for (kn = kr; kn; kn = kn->next) {
			r = ospf_redistribute(&kn->r, &dummy);
			/*
			 * if it is redistributed, redistribute again metric
			 * may have changed.
			 */
			if ((kn->r.flags & F_REDISTRIBUTED && !r) || r)
				break;
		}
		if (kn) {
			/*
			 * kr_redistribute copes with removes and RDE with
			 * duplicates
			 */
			kr_redistribute(kr);
		}
	}
}

/* rb-tree compare */
int
kroute_compare(struct kroute_node *a, struct kroute_node *b)
{
	int	i;

	/* XXX maybe switch a & b */
	i = memcmp(&a->r.prefix, &b->r.prefix, sizeof(a->r.prefix));
	if (i)
		return (i);
	if (a->r.prefixlen < b->r.prefixlen)
		return (-1);
	if (a->r.prefixlen > b->r.prefixlen)
		return (1);
	return (0);
}

int
kif_compare(struct kif_node *a, struct kif_node *b)
{
	return (b->k.ifindex - a->k.ifindex);
}

/* tree management */
struct kroute_node *
kroute_find(const struct in6_addr *prefix, u_int8_t prefixlen)
{
	struct kroute_node	s;

	s.r.prefix = *prefix;
	s.r.prefixlen = prefixlen;

	return (RB_FIND(kroute_tree, &krt, &s));
}

struct kroute_node *
kroute_matchgw(struct kroute_node *kr, struct in6_addr *nh)
{
	while (kr) {
		if (IN6_ARE_ADDR_EQUAL(&kr->r.nexthop, nh))
			return (kr);
		kr = kr->next;
	}

	return (NULL);
}

int
kroute_insert(struct kroute_node *kr)
{
	struct kroute_node	*krm;

	if ((krm = RB_INSERT(kroute_tree, &krt, kr)) != NULL) {
		/*
		 * Multipath route, add at end of list and clone the
		 * ospfd inserted flag.
		 */
		kr->r.flags |= krm->r.flags & F_OSPFD_INSERTED;
		while (krm->next != NULL)
			krm = krm->next;
		krm->next = kr;
		kr->next = NULL; /* to be sure */
	} else
		krm = kr;

	if (!(kr->r.flags & F_KERNEL)) {
		/* don't validate or redistribute ospf route */
		kr->r.flags &= ~F_DOWN;
		return (0);
	}

	if (kif_validate(kr->r.ifindex))
		kr->r.flags &= ~F_DOWN;
	else
		kr->r.flags |= F_DOWN;

	kr_redistribute(krm);
	return (0);
}

int
kroute_remove(struct kroute_node *kr)
{
	struct kroute_node	*krm;

	if ((krm = RB_FIND(kroute_tree, &krt, kr)) == NULL) {
		log_warnx("kroute_remove failed to find %s/%u",
		    log_in6addr(&kr->r.prefix), kr->r.prefixlen);
		return (-1);
	}

	if (krm == kr) {
		/* head element */
		if (RB_REMOVE(kroute_tree, &krt, kr) == NULL) {
			log_warnx("kroute_remove failed for %s/%u",
			    log_in6addr(&kr->r.prefix), kr->r.prefixlen);
			return (-1);
		}
		if (kr->next != NULL) {
			if (RB_INSERT(kroute_tree, &krt, kr->next) != NULL) {
				log_warnx("kroute_remove failed to add %s/%u",
				    log_in6addr(&kr->r.prefix),
				    kr->r.prefixlen);
				return (-1);
			}
		}
	} else {
		/* somewhere in the list */
		while (krm->next != kr && krm->next != NULL)
			krm = krm->next;
		if (krm->next == NULL) {
			log_warnx("kroute_remove multipath list corrupted "
			    "for %s/%u", log_in6addr(&kr->r.prefix),
			    kr->r.prefixlen);
			return (-1);
		}
		krm->next = kr->next;
	}

	kr_redist_remove(krm, kr);
	rtlabel_unref(kr->r.rtlabel);

	free(kr);
	return (0);
}

void
kroute_clear(void)
{
	struct kroute_node	*kr;

	while ((kr = RB_MIN(kroute_tree, &krt)) != NULL)
		kroute_remove(kr);
}

struct kif_node *
kif_find(u_short ifindex)
{
	struct kif_node	s;

	bzero(&s, sizeof(s));
	s.k.ifindex = ifindex;

	return (RB_FIND(kif_tree, &kit, &s));
}

struct kif *
kif_findname(char *ifname, struct kif_addr **kap)
{
	struct kif_node	*kif;
	struct kif_addr	*ka;

	RB_FOREACH(kif, kif_tree, &kit)
		if (!strcmp(ifname, kif->k.ifname)) {
			ka = TAILQ_FIRST(&kif->addrs);
			if (kap != NULL)
				*kap = ka;
			return (&kif->k);
		}

	return (NULL);
}

struct kif_node *
kif_insert(u_short ifindex)
{
	struct kif_node	*kif;

	if ((kif = calloc(1, sizeof(struct kif_node))) == NULL)
		return (NULL);

	kif->k.ifindex = ifindex;
	TAILQ_INIT(&kif->addrs);

	if (RB_INSERT(kif_tree, &kit, kif) != NULL)
		fatalx("kif_insert: RB_INSERT");

	return (kif);
}

int
kif_remove(struct kif_node *kif)
{
	struct kif_addr	*ka;

	if (RB_REMOVE(kif_tree, &kit, kif) == NULL) {
		log_warnx("RB_REMOVE(kif_tree, &kit, kif)");
		return (-1);
	}

	while ((ka = TAILQ_FIRST(&kif->addrs)) != NULL) {
		TAILQ_REMOVE(&kif->addrs, ka, entry);
		free(ka);
	}
	free(kif);
	return (0);
}

void
kif_clear(void)
{
	struct kif_node	*kif;

	while ((kif = RB_MIN(kif_tree, &kit)) != NULL)
		kif_remove(kif);
}

struct kif *
kif_update(u_short ifindex, int flags, struct if_data *ifd,
    struct sockaddr_dl *sdl)
{
	struct kif_node		*kif;

	if ((kif = kif_find(ifindex)) == NULL)
		if ((kif = kif_insert(ifindex)) == NULL)
			return (NULL);

	kif->k.flags = flags;
	kif->k.link_state = ifd->ifi_link_state;
	kif->k.media_type = ifd->ifi_type;
	kif->k.baudrate = ifd->ifi_baudrate;
	kif->k.mtu = ifd->ifi_mtu;

	if (sdl && sdl->sdl_family == AF_LINK) {
		if (sdl->sdl_nlen >= sizeof(kif->k.ifname))
			memcpy(kif->k.ifname, sdl->sdl_data,
			    sizeof(kif->k.ifname) - 1);
		else if (sdl->sdl_nlen > 0)
			memcpy(kif->k.ifname, sdl->sdl_data,
			    sdl->sdl_nlen);
		/* string already terminated via calloc() */
	}

	return (&kif->k);
}

int
kif_validate(u_short ifindex)
{
	struct kif_node		*kif;

	if ((kif = kif_find(ifindex)) == NULL) {
		log_warnx("interface with index %u not found", ifindex);
		return (1);
	}

	return (kif->k.nh_reachable);
}

struct kroute_node *
kroute_match(struct in6_addr *key)
{
	int			 i;
	struct kroute_node	*kr;
	struct in6_addr		 ina;

	/* we will never match the default route */
	for (i = 128; i > 0; i--) {
		inet6applymask(&ina, key, i);
		if ((kr = kroute_find(&ina, i)) != NULL)
			return (kr);
	}

	/* if we don't have a match yet, try to find a default route */
	if ((kr = kroute_find(&in6addr_any, 0)) != NULL)
			return (kr);

	return (NULL);
}

/* misc */
int
protect_lo(void)
{
	struct kroute_node	*kr;

	/* special protection for loopback */
	if ((kr = calloc(1, sizeof(struct kroute_node))) == NULL) {
		log_warn("protect_lo");
		return (-1);
	}
	memcpy(&kr->r.prefix, &in6addr_loopback, sizeof(kr->r.prefix));
	kr->r.prefixlen = 128;
	kr->r.flags = F_KERNEL|F_CONNECTED;

	if (RB_INSERT(kroute_tree, &krt, kr) != NULL)
		free(kr);	/* kernel route already there, no problem */

	return (0);
}

u_int8_t
mask2prefixlen(struct sockaddr_in6 *sa_in6)
{
	u_int8_t	l = 0, i, len;

	/*
	 * sin6_len is the size of the sockaddr so substract the offset of
	 * the possibly truncated sin6_addr struct.
	 */
	len = sa_in6->sin6_len -
	    (u_int8_t)(&((struct sockaddr_in6 *)NULL)->sin6_addr);
	for (i = 0; i < len; i++) {
		/* this "beauty" is adopted from sbin/route/show.c ... */
		switch (sa_in6->sin6_addr.s6_addr[i]) {
		case 0xff:
			l += 8;
			break;
		case 0xfe:
			l += 7;
			return (l);
		case 0xfc:
			l += 6;
			return (l);
		case 0xf8:
			l += 5;
			return (l);
		case 0xf0:
			l += 4;
			return (l);
		case 0xe0:
			l += 3;
			return (l);
		case 0xc0:
			l += 2;
			return (l);
		case 0x80:
			l += 1;
			return (l);
		case 0x00:
			return (l);
		default:
			fatalx("non continguous inet6 netmask");
		}
	}

	return (l);
}

struct in6_addr *
prefixlen2mask(u_int8_t prefixlen)
{
	static struct in6_addr	mask;
	int			i;

	bzero(&mask, sizeof(mask));
	for (i = 0; i < prefixlen / 8; i++)
		mask.s6_addr[i] = 0xff;
	i = prefixlen % 8;
	if (i)
		mask.s6_addr[prefixlen / 8] = 0xff00 >> i;

	return (&mask);
}

void
inet6applymask(struct in6_addr *dest, const struct in6_addr *src, int prefixlen)
{
	struct in6_addr	mask;
	int		i;

	bzero(&mask, sizeof(mask));
	for (i = 0; i < prefixlen / 8; i++)
		mask.s6_addr[i] = 0xff;
	i = prefixlen % 8;
	if (i)
		mask.s6_addr[prefixlen / 8] = 0xff00 >> i;

	for (i = 0; i < 16; i++)
		dest->s6_addr[i] = src->s6_addr[i] & mask.s6_addr[i];
}

#define	ROUNDUP(a, size)	\
    (((a) & ((size) - 1)) ? (1 + ((a) | ((size) - 1))) : (a))

void
get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
{
	int	i;

	for (i = 0; i < RTAX_MAX; i++) {
		if (addrs & (1 << i)) {
			rti_info[i] = sa;
			sa = (struct sockaddr *)((char *)(sa) +
			    ROUNDUP(sa->sa_len, sizeof(long)));
		} else
			rti_info[i] = NULL;
	}
}

void
if_change(u_short ifindex, int flags, struct if_data *ifd)
{
	struct kroute_node	*kr, *tkr;
	struct kif		*kif;
	u_int8_t		 reachable;

	if ((kif = kif_update(ifindex, flags, ifd, NULL)) == NULL) {
		log_warn("if_change:  kif_update(%u)", ifindex);
		return;
	}

	reachable = (kif->flags & IFF_UP) &&
	    (LINK_STATE_IS_UP(kif->link_state) ||
	    (kif->link_state == LINK_STATE_UNKNOWN &&
	    kif->media_type != IFT_CARP));

	if (reachable == kif->nh_reachable)
		return;		/* nothing changed wrt nexthop validity */

	kif->nh_reachable = reachable;

	/* notify ospfe about interface link state */
	main_imsg_compose_ospfe(IMSG_IFINFO, 0, kif, sizeof(struct kif));

	/* update redistribute list */
	RB_FOREACH(kr, kroute_tree, &krt) {
		for (tkr = kr; tkr != NULL; tkr = tkr->next) {
			if (tkr->r.ifindex == ifindex) {
				if (reachable)
					tkr->r.flags &= ~F_DOWN;
				else
					tkr->r.flags |= F_DOWN;

			}
		}
		kr_redistribute(kr);
	}
}

void
if_newaddr(u_short ifindex, struct sockaddr_in6 *ifa, struct sockaddr_in6 *mask,
    struct sockaddr_in6 *brd)
{
	struct kif_node *kif;
	struct kif_addr *ka;

	if (ifa == NULL || ifa->sin6_family != AF_INET6)
		return;
	if ((kif = kif_find(ifindex)) == NULL) {
		log_warnx("if_newaddr: corresponding if %i not found", ifindex);
		return;
	}
	if ((ka = calloc(1, sizeof(struct kif_addr))) == NULL)
		fatal("if_newaddr");
	ka->addr = ifa->sin6_addr;

	/* XXX thanks, KAME, for this ugliness... adopted from route/show.c */
	if (IN6_IS_ADDR_LINKLOCAL(&ka->addr) ||
	    IN6_IS_ADDR_MC_LINKLOCAL(&ka->addr)) {
		ka->addr.s6_addr[2] = 0;
		ka->addr.s6_addr[3] = 0;
	}

	if (mask)
		ka->mask = mask->sin6_addr;
	else
		bzero(&ka->mask, sizeof(ka->mask));
	if (brd)
		ka->dstbrd = brd->sin6_addr;
	else
		bzero(&ka->dstbrd, sizeof(ka->dstbrd));

	log_debug("if_newaddr: ifindex %u, addr %s", ifindex,
	    log_in6addr(&ka->addr));
	TAILQ_INSERT_TAIL(&kif->addrs, ka, entry);
}

void
if_announce(void *msg)
{
	struct if_announcemsghdr	*ifan;
	struct kif_node			*kif;

	ifan = msg;

	switch (ifan->ifan_what) {
	case IFAN_ARRIVAL:
		kif = kif_insert(ifan->ifan_index);
		strlcpy(kif->k.ifname, ifan->ifan_name, sizeof(kif->k.ifname));
		break;
	case IFAN_DEPARTURE:
		kif = kif_find(ifan->ifan_index);
		kif_remove(kif);
		break;
	}
}

/* rtsock */
int
send_rtmsg(int fd, int action, struct kroute *kroute)
{
	struct iovec		iov[5];
	struct rt_msghdr	hdr;
	struct sockaddr_in6	prefix;
	struct sockaddr_in6	nexthop;
	struct sockaddr_in6	mask;
	struct sockaddr_rtlabel	sa_rl;
	int			iovcnt = 0;
	const char		*label;

	if (kr_state.fib_sync == 0)
		return (0);

	/* initialize header */
	bzero(&hdr, sizeof(hdr));
	hdr.rtm_version = RTM_VERSION;
	hdr.rtm_type = action;
	hdr.rtm_flags = RTF_PROTO2;
	if (action == RTM_CHANGE)	/* force PROTO2 reset the other flags */
		hdr.rtm_fmask = RTF_PROTO2|RTF_PROTO1|RTF_REJECT|RTF_BLACKHOLE;
	hdr.rtm_seq = kr_state.rtseq++;	/* overflow doesn't matter */
	hdr.rtm_msglen = sizeof(hdr);
	/* adjust iovec */
	iov[iovcnt].iov_base = &hdr;
	iov[iovcnt++].iov_len = sizeof(hdr);

	bzero(&prefix, sizeof(prefix));
	prefix.sin6_len = sizeof(prefix);
	prefix.sin6_family = AF_INET6;
	prefix.sin6_addr = kroute->prefix;
	/* adjust header */
	hdr.rtm_addrs |= RTA_DST;
	hdr.rtm_msglen += sizeof(prefix);
	/* adjust iovec */
	iov[iovcnt].iov_base = &prefix;
	iov[iovcnt++].iov_len = sizeof(prefix);

	if (!IN6_IS_ADDR_UNSPECIFIED(&kroute->nexthop)) {
		bzero(&nexthop, sizeof(nexthop));
		nexthop.sin6_len = sizeof(nexthop);
		nexthop.sin6_family = AF_INET6;
		nexthop.sin6_addr = kroute->nexthop;
		/* adjust header */
		hdr.rtm_flags |= RTF_GATEWAY;
		hdr.rtm_addrs |= RTA_GATEWAY;
		hdr.rtm_msglen += sizeof(nexthop);
		/* adjust iovec */
		iov[iovcnt].iov_base = &nexthop;
		iov[iovcnt++].iov_len = sizeof(nexthop);
	}

	bzero(&mask, sizeof(mask));
	mask.sin6_len = sizeof(mask);
	mask.sin6_family = AF_INET6;
	mask.sin6_addr = *prefixlen2mask(kroute->prefixlen);
	/* adjust header */
	hdr.rtm_addrs |= RTA_NETMASK;
	hdr.rtm_msglen += sizeof(mask);
	/* adjust iovec */
	iov[iovcnt].iov_base = &mask;
	iov[iovcnt++].iov_len = sizeof(mask);

	if (kroute->rtlabel != 0) {
		sa_rl.sr_len = sizeof(sa_rl);
		sa_rl.sr_family = AF_UNSPEC;
		label = rtlabel_id2name(kroute->rtlabel);
		if (strlcpy(sa_rl.sr_label, label,
		    sizeof(sa_rl.sr_label)) >= sizeof(sa_rl.sr_label)) {
			log_warnx("send_rtmsg: invalid rtlabel");
			return (-1);
		}
		/* adjust header */
		hdr.rtm_addrs |= RTA_LABEL;
		hdr.rtm_msglen += sizeof(sa_rl);
		/* adjust iovec */
		iov[iovcnt].iov_base = &sa_rl;
		iov[iovcnt++].iov_len = sizeof(sa_rl);
	}

retry:
	if (writev(fd, iov, iovcnt) == -1) {
		switch (errno) {
		case ESRCH:
			if (hdr.rtm_type == RTM_CHANGE) {
				hdr.rtm_type = RTM_ADD;
				goto retry;
			} else if (hdr.rtm_type == RTM_DELETE) {
				log_info("route %s/%u vanished before delete",
				    log_sockaddr(&prefix), kroute->prefixlen);
				return (0);
			} else {
				log_warn("send_rtmsg: action %u, "
				    "prefix %s/%u", hdr.rtm_type,
				    log_sockaddr(&prefix), kroute->prefixlen);
				return (0);
			}
			break;
		default:
			log_warn("send_rtmsg: action %u, prefix %s/%u",
			    hdr.rtm_type, log_sockaddr(&prefix),
			    kroute->prefixlen);
			return (0);
		}
	}

	return (0);
}

int
fetchtable(void)
{
	size_t			 len;
	int			 mib[7];
	char			*buf, *next, *lim;
	struct rt_msghdr	*rtm;
	struct sockaddr		*sa, *rti_info[RTAX_MAX];
	struct sockaddr_in6	*sa_in6;
	struct sockaddr_rtlabel	*label;
	struct kroute_node	*kr;

	mib[0] = CTL_NET;
	mib[1] = AF_ROUTE;
	mib[2] = 0;
	mib[3] = AF_INET;
	mib[4] = NET_RT_DUMP;
	mib[5] = 0;
	mib[6] = 0;	/* rtableid */

	if (sysctl(mib, 7, NULL, &len, NULL, 0) == -1) {
		log_warn("sysctl");
		return (-1);
	}
	if ((buf = malloc(len)) == NULL) {
		log_warn("fetchtable");
		return (-1);
	}
	if (sysctl(mib, 7, buf, &len, NULL, 0) == -1) {
		log_warn("sysctl");
		free(buf);
		return (-1);
	}

	lim = buf + len;
	for (next = buf; next < lim; next += rtm->rtm_msglen) {
		rtm = (struct rt_msghdr *)next;
		if (rtm->rtm_version != RTM_VERSION)
			continue;
		sa = (struct sockaddr *)(rtm + 1);
		get_rtaddrs(rtm->rtm_addrs, sa, rti_info);

		if ((sa = rti_info[RTAX_DST]) == NULL)
			continue;

		if (rtm->rtm_flags & RTF_LLINFO)	/* arp cache */
			continue;

		if ((kr = calloc(1, sizeof(struct kroute_node))) == NULL) {
			log_warn("fetchtable");
			free(buf);
			return (-1);
		}

		kr->r.flags = F_KERNEL;

		switch (sa->sa_family) {
		case AF_INET6:
			kr->r.prefix =
			    ((struct sockaddr_in6 *)sa)->sin6_addr;
			sa_in6 = (struct sockaddr_in6 *)rti_info[RTAX_NETMASK];
			if (rtm->rtm_flags & RTF_STATIC)
				kr->r.flags |= F_STATIC;
			if (rtm->rtm_flags & RTF_DYNAMIC)
				kr->r.flags |= F_DYNAMIC;
			if (rtm->rtm_flags & RTF_PROTO1)
				kr->r.flags |= F_BGPD_INSERTED;
			if (sa_in6 != NULL) {
				if (sa_in6->sin6_len == 0)
					break;
				kr->r.prefixlen =
				    mask2prefixlen(sa_in6);
			} else if (rtm->rtm_flags & RTF_HOST)
				kr->r.prefixlen = 128;
			else
				fatalx("classful IPv6 route?!!");
			break;
		default:
			free(kr);
			continue;
		}

		kr->r.ifindex = rtm->rtm_index;
		if ((sa = rti_info[RTAX_GATEWAY]) != NULL)
			switch (sa->sa_family) {
			case AF_INET6:
				kr->r.nexthop =
				    ((struct sockaddr_in6 *)sa)->sin6_addr;
				break;
			case AF_LINK:
				kr->r.flags |= F_CONNECTED;
				break;
			}

		if (rtm->rtm_flags & RTF_PROTO2)  {
			send_rtmsg(kr_state.fd, RTM_DELETE, &kr->r);
			free(kr);
		} else {
			if ((label = (struct sockaddr_rtlabel *)
			    rti_info[RTAX_LABEL]) != NULL) {
				kr->r.rtlabel =
				    rtlabel_name2id(label->sr_label);
				kr->r.ext_tag =
				    rtlabel_id2tag(kr->r.rtlabel);
			}
			kroute_insert(kr);
		}

	}
	free(buf);
	return (0);
}

int
fetchifs(u_short ifindex)
{
	size_t			 len;
	int			 mib[6];
	char			*buf, *next, *lim;
	struct rt_msghdr	*rtm;
	struct if_msghdr	 ifm;
	struct ifa_msghdr	*ifam;
	struct kif		*kif = NULL;
	struct sockaddr		*sa, *rti_info[RTAX_MAX];

	mib[0] = CTL_NET;
	mib[1] = AF_ROUTE;
	mib[2] = 0;
	mib[3] = AF_INET6;
	mib[4] = NET_RT_IFLIST;
	mib[5] = ifindex;

	if (sysctl(mib, 6, NULL, &len, NULL, 0) == -1) {
		log_warn("sysctl");
		return (-1);
	}
	if ((buf = malloc(len)) == NULL) {
		log_warn("fetchif");
		return (-1);
	}
	if (sysctl(mib, 6, buf, &len, NULL, 0) == -1) {
		log_warn("sysctl");
		free(buf);
		return (-1);
	}

	lim = buf + len;
	for (next = buf; next < lim; next += rtm->rtm_msglen) {
		rtm = (struct rt_msghdr *)next;
		if (rtm->rtm_version != RTM_VERSION)
			continue;
		switch (rtm->rtm_type) {
		case RTM_IFINFO:
			bcopy(rtm, &ifm, sizeof ifm);
			sa = (struct sockaddr *)(next + sizeof(ifm));
			get_rtaddrs(ifm.ifm_addrs, sa, rti_info);

			if ((kif = kif_update(ifm.ifm_index,
			    ifm.ifm_flags, &ifm.ifm_data,
			    (struct sockaddr_dl *)rti_info[RTAX_IFP])) == NULL)
				fatal("fetchifs");

			kif->nh_reachable = (kif->flags & IFF_UP) &&
			    (LINK_STATE_IS_UP(ifm.ifm_data.ifi_link_state) ||
			    (ifm.ifm_data.ifi_link_state ==
			    LINK_STATE_UNKNOWN &&
			    ifm.ifm_data.ifi_type != IFT_CARP));
			break;
		case RTM_NEWADDR:
			ifam = (struct ifa_msghdr *)rtm;
			if ((ifam->ifam_addrs & (RTA_NETMASK | RTA_IFA |
			    RTA_BRD)) == 0)
				break;
			sa = (struct sockaddr *)(ifam + 1);
			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);

			if_newaddr(ifam->ifam_index,
			    (struct sockaddr_in6 *)rti_info[RTAX_IFA],
			    (struct sockaddr_in6 *)rti_info[RTAX_NETMASK],
			    (struct sockaddr_in6 *)rti_info[RTAX_BRD]);
			break;
		}
	}
	free(buf);
	return (0);
}

int
dispatch_rtmsg(void)
{
	char			 buf[RT_BUF_SIZE];
	ssize_t			 n;
	char			*next, *lim;
	struct rt_msghdr	*rtm;
	struct if_msghdr	 ifm;
	struct ifa_msghdr	*ifam;
	struct sockaddr		*sa, *rti_info[RTAX_MAX];
	struct sockaddr_in6	*sa_in6;
	struct sockaddr_rtlabel	*label;
	struct kroute_node	*kr, *okr;
	struct in6_addr		 prefix, nexthop;
	u_int8_t		 prefixlen;
	int			 flags, mpath;
	u_short			 ifindex = 0;

	if ((n = read(kr_state.fd, &buf, sizeof(buf))) == -1) {
		log_warn("dispatch_rtmsg: read error");
		return (-1);
	}

	if (n == 0) {
		log_warnx("routing socket closed");
		return (-1);
	}

	lim = buf + n;
	for (next = buf; next < lim; next += rtm->rtm_msglen) {
		rtm = (struct rt_msghdr *)next;
		if (rtm->rtm_version != RTM_VERSION)
			continue;

		bzero(&prefix, sizeof(prefix));
		bzero(&nexthop, sizeof(nexthop));
		prefixlen = 0;
		flags = F_KERNEL;
		mpath = 0;

		if (rtm->rtm_type == RTM_ADD || rtm->rtm_type == RTM_CHANGE ||
		    rtm->rtm_type == RTM_DELETE) {
			sa = (struct sockaddr *)(rtm + 1);
			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);

			if (rtm->rtm_tableid != 0)
				continue;

			if (rtm->rtm_pid == kr_state.pid) /* caused by us */
				continue;

			if (rtm->rtm_errno)		/* failed attempts... */
				continue;

			if (rtm->rtm_flags & RTF_LLINFO)	/* arp cache */
				continue;

#ifdef RTF_MPATH
			if (rtm->rtm_flags & RTF_MPATH)
				mpath = 1;
#endif
			switch (sa->sa_family) {
			case AF_INET6:
				prefix =
				    ((struct sockaddr_in6 *)sa)->sin6_addr;
				sa_in6 = (struct sockaddr_in6 *)
				    rti_info[RTAX_NETMASK];
				if (sa_in6 != NULL) {
					if (sa_in6->sin6_len != 0)
						prefixlen = mask2prefixlen(
						    sa_in6);
				} else if (rtm->rtm_flags & RTF_HOST)
					prefixlen = 128;
				else
					fatalx("classful IPv6 address?!!");
				if (rtm->rtm_flags & RTF_STATIC)
					flags |= F_STATIC;
				if (rtm->rtm_flags & RTF_DYNAMIC)
					flags |= F_DYNAMIC;
				if (rtm->rtm_flags & RTF_PROTO1)
					flags |= F_BGPD_INSERTED;
				break;
			default:
				continue;
			}

			ifindex = rtm->rtm_index;
			if ((sa = rti_info[RTAX_GATEWAY]) != NULL) {
				switch (sa->sa_family) {
				case AF_INET:
					nexthop = ((struct sockaddr_in6 *)
					    sa)->sin6_addr;
					break;
				case AF_LINK:
					flags |= F_CONNECTED;
					break;
				}
			}
		}

		switch (rtm->rtm_type) {
		case RTM_ADD:
		case RTM_CHANGE:
			if (IN6_IS_ADDR_UNSPECIFIED(&nexthop) == 0 &&
			    !(flags & F_CONNECTED)) {
				log_warnx("dispatch_rtmsg no nexthop for %s/%u",
				    log_in6addr(&prefix), prefixlen);
				continue;
			}

			if ((okr = kroute_find(&prefix, prefixlen)) !=
			    NULL) {
				/* just add new multipath routes */
				if (mpath && rtm->rtm_type == RTM_ADD)
					goto add;
				/* get the correct route */
				kr = okr;
				if (mpath && (kr = kroute_matchgw(okr,
				    &nexthop)) == NULL) {
					log_warnx("dispatch_rtmsg mpath route"
					    " not found");
					/* add routes we missed out earlier */
					goto add;
				}

				/*
				 * ospf route overridden by kernel. Preference
				 * of the route is not checked because this is
				 * forced -- most probably by a user.
				 */
				if (kr->r.flags & F_OSPFD_INSERTED)
					flags |= F_OSPFD_INSERTED;
				if (kr->r.flags & F_REDISTRIBUTED)
					flags |= F_REDISTRIBUTED;
				kr->r.nexthop = nexthop;
				kr->r.flags = flags;
				kr->r.ifindex = ifindex;

				rtlabel_unref(kr->r.rtlabel);
				kr->r.rtlabel = 0;
				kr->r.ext_tag = 0;
				if ((label = (struct sockaddr_rtlabel *)
				    rti_info[RTAX_LABEL]) != NULL) {
					kr->r.rtlabel =
					    rtlabel_name2id(label->sr_label);
					kr->r.ext_tag =
					    rtlabel_id2tag(kr->r.rtlabel);
				}

				if (kif_validate(kr->r.ifindex))
					kr->r.flags &= ~F_DOWN;
				else
					kr->r.flags |= F_DOWN;

				/* just readd, the RDE will care */
				kr_redistribute(okr);
			} else {
add:
				if ((kr = calloc(1,
				    sizeof(struct kroute_node))) == NULL) {
					log_warn("dispatch_rtmsg");
					return (-1);
				}
				kr->r.prefix = prefix;
				kr->r.prefixlen = prefixlen;
				kr->r.nexthop = nexthop;
				kr->r.flags = flags;
				kr->r.ifindex = ifindex;

				if ((label = (struct sockaddr_rtlabel *)
				    rti_info[RTAX_LABEL]) != NULL) {
					kr->r.rtlabel =
					    rtlabel_name2id(label->sr_label);
					kr->r.ext_tag =
					    rtlabel_id2tag(kr->r.rtlabel);
				}

				kroute_insert(kr);
			}
			break;
		case RTM_DELETE:
			if ((kr = kroute_find(&prefix, prefixlen)) ==
			    NULL)
				continue;
			if (!(kr->r.flags & F_KERNEL))
				continue;
			/* get the correct route */
			okr = kr;
			if (mpath &&
			    (kr = kroute_matchgw(kr, &nexthop)) == NULL) {
				log_warnx("dispatch_rtmsg mpath route"
				    " not found");
				return (-1);
			}
			/*
			 * last route is getting removed request the
			 * ospf route from the RDE to insert instead
			 */
			if (okr == kr && kr->next == NULL &&
			    kr->r.flags & F_OSPFD_INSERTED)
				main_imsg_compose_rde(IMSG_KROUTE_GET, 0,
				    &kr->r, sizeof(struct kroute));
			if (kroute_remove(kr) == -1)
				return (-1);
			break;
		case RTM_IFINFO:
			memcpy(&ifm, next, sizeof(ifm));
			if_change(ifm.ifm_index, ifm.ifm_flags,
			    &ifm.ifm_data);
			break;
		case RTM_NEWADDR:
			ifam = (struct ifa_msghdr *)rtm;
			if ((ifam->ifam_addrs & (RTA_NETMASK | RTA_IFA |
			    RTA_BRD)) == 0)
				break;
			sa = (struct sockaddr *)(ifam + 1);
			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);

			if_newaddr(ifam->ifam_index,
			    (struct sockaddr_in6 *)rti_info[RTAX_IFA],
			    (struct sockaddr_in6 *)rti_info[RTAX_NETMASK],
			    (struct sockaddr_in6 *)rti_info[RTAX_BRD]);
			break;
		case RTM_IFANNOUNCE:
			if_announce(next);
			break;
		default:
			/* ignore for now */
			break;
		}
	}
	return (0);
}