/*	$OpenBSD: kroute.c,v 1.21 2005/12/14 00:44:40 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 <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_dl.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 "ospfd.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 kif_kr {
	LIST_ENTRY(kif_kr)	 entry;
	struct kroute_node	*kr;
};

struct kif_node {
	RB_ENTRY(kif_node)	 entry;
	struct kif		 k;
};

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

struct kroute_node	*kroute_find(in_addr_t, u_int8_t);
int			 kroute_insert(struct kroute_node *);
int			 kroute_remove(struct kroute_node *);
void			 kroute_clear(void);

struct kif_node		*kif_find(int);
int			 kif_insert(struct kif_node *);
int			 kif_remove(struct kif_node *);
void			 kif_clear(void);

struct kroute_node	*kroute_match(in_addr_t);

int		protect_lo(void);
u_int8_t	prefixlen_classful(in_addr_t);
void		get_rtaddrs(int, struct sockaddr *, struct sockaddr **);
void		if_change(u_short, int, struct if_data *);
void		if_announce(void *);

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

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;

	if ((kr = kroute_find(kroute->prefix.s_addr, kroute->prefixlen)) !=
	    NULL) {
		if (kr->r.flags & F_OSPFD_INSERTED)
			action = RTM_CHANGE;
		else	/* a non-ospf route already exists. not a problem */
			return (0);
	}

	/* nexthop within 127/8 -> ignore silently */
	if ((kroute->nexthop.s_addr & htonl(0xff000000)) ==
	    inet_addr("127.0.0.0"))
		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.s_addr = kroute->prefix.s_addr;
		kr->r.prefixlen = kroute->prefixlen;
		kr->r.nexthop.s_addr = kroute->nexthop.s_addr;
		kr->r.flags = kroute->flags | F_OSPFD_INSERTED;

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

	return (0);
}

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

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

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

	/* nexthop within 127/8 -> ignore silently */
	if ((kroute->nexthop.s_addr & htonl(0xff000000)) ==
	    inet_addr("127.0.0.0"))
		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_OSPFD_INSERTED))
			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_OSPFD_INSERTED))
			send_rtmsg(kr_state.fd, RTM_DELETE, &kr->r);

	kr_state.fib_sync = 0;

	log_info("kernel routing table decoupled");
}

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

void
kr_show_route(struct imsg *imsg)
{
	struct kroute_node	*kr;
	int			 flags;
	struct in_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) {
				main_imsg_compose_ospfe(IMSG_CTL_KROUTE,
				    imsg->hdr.pid, &kr->r, sizeof(kr->r));
			}
		break;
	case IMSG_CTL_KROUTE_ADDR:
		if (imsg->hdr.len != IMSG_HEADER_SIZE +
		    sizeof(struct in_addr)) {
			log_warnx("kr_show_route: wrong imsg len");
			return;
		}
		memcpy(&addr, imsg->data, sizeof(addr));
		kr = NULL;
		kr = kroute_match(addr.s_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_redistribute(int type, struct kroute *kr)
{
	u_int32_t	a;

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

	/*
	 * We consider the loopback net, multicast and experimental addresses
	 * as not redistributable.
	 */
	a = ntohl(kr->prefix.s_addr);
	if (IN_MULTICAST(a) || IN_BADCLASS(a) ||
	    (a >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET)
		return;
	/*
	 * Consider networks with nexthop loopback as not redistributable.
	 */
	if (kr->nexthop.s_addr == htonl(INADDR_LOOPBACK))
		return;

	main_imsg_compose_rde(type, 0, kr, sizeof(struct kroute));
}

/* rb-tree compare */
int
kroute_compare(struct kroute_node *a, struct kroute_node *b)
{
	if (ntohl(a->r.prefix.s_addr) < ntohl(b->r.prefix.s_addr))
		return (-1);
	if (ntohl(a->r.prefix.s_addr) > ntohl(b->r.prefix.s_addr))
		return (1);
	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(in_addr_t prefix, u_int8_t prefixlen)
{
	struct kroute_node	s;

	s.r.prefix.s_addr = prefix;
	s.r.prefixlen = prefixlen;

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

int
kroute_insert(struct kroute_node *kr)
{
	if (RB_INSERT(kroute_tree, &krt, kr) != NULL) {
		log_warnx("kroute_tree insert failed for %s/%u",
		    inet_ntoa(kr->r.prefix), kr->r.prefixlen);
		free(kr);
		return (-1);
	}

	if (kr->r.flags & F_KERNEL)
		kr_redistribute(IMSG_NETWORK_ADD, &kr->r);

	return (0);
}

int
kroute_remove(struct kroute_node *kr)
{
	if (RB_REMOVE(kroute_tree, &krt, kr) == NULL) {
		log_warnx("kroute_remove failed for %s/%u",
		    inet_ntoa(kr->r.prefix), kr->r.prefixlen);
		return (-1);
	}

	if (kr->r.flags & F_KERNEL)
		kr_redistribute(IMSG_NETWORK_DEL, &kr->r);

	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(int 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_node	*kif;

	RB_FOREACH(kif, kif_tree, &kit)
		if (!strcmp(ifname, kif->k.ifname))
			return (&kif->k);

	return (NULL);
}

int
kif_insert(struct kif_node *kif)
{
	if (RB_INSERT(kif_tree, &kit, kif) != NULL) {
		log_warnx("RB_INSERT(kif_tree, &kit, kif)");
		free(kif);
		return (-1);
	}

	return (0);
}

int
kif_remove(struct kif_node *kif)
{
	if (RB_REMOVE(kif_tree, &kit, kif) == NULL) {
		log_warnx("RB_REMOVE(kif_tree, &kit, kif)");
		return (-1);
	}

	free(kif);
	return (0);
}

void
kif_clear(void)
{
	struct kif_node	*kif;

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

void
kif_update(struct kif *k)
{
	struct kif_node		*kif;

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

	memcpy(&kif->k, k, sizeof(struct kif));
}

int
kif_validate(int 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(in_addr_t key)
{
	int			 i;
	struct kroute_node	*kr;

	/* we will never match the default route */
	for (i = 32; i > 0; i--)
		if ((kr = kroute_find(key & prefixlen2mask(i), i)) != NULL)
			return (kr);

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

	return (NULL);
}

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

	/* special protection for 127/8 */
	if ((kr = calloc(1, sizeof(struct kroute_node))) == NULL) {
		log_warn("protect_lo");
		return (-1);
	}
	kr->r.prefix.s_addr = inet_addr("127.0.0.1");
	kr->r.prefixlen = 8;
	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
prefixlen_classful(in_addr_t ina)
{
	/* it hurt to write this. */

	if (ina >= 0xf0000000U)		/* class E */
		return (32);
	else if (ina >= 0xe0000000U)	/* class D */
		return (4);
	else if (ina >= 0xc0000000U)	/* class C */
		return (24);
	else if (ina >= 0x80000000U)	/* class B */
		return (16);
	else				/* class A */
		return (8);
}

u_int8_t
mask2prefixlen(in_addr_t ina)
{
	if (ina == 0)
		return (0);
	else
		return (33 - ffs(ntohl(ina)));
}

in_addr_t
prefixlen2mask(u_int8_t prefixlen)
{
	if (prefixlen == 0)
		return (0);

	return (htonl(0xffffffff << (32 - prefixlen)));
}

#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 kif_node		*kif;
	u_int8_t		 reachable;

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

	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;

	if ((reachable = (flags & IFF_UP) &&
	    (ifd->ifi_link_state != LINK_STATE_DOWN)) == kif->k.nh_reachable)
		return;		/* nothing changed wrt nexthop validity */

	kif->k.nh_reachable = reachable;
	main_imsg_compose_ospfe(IMSG_IFINFO, 0, &kif->k, sizeof(kif->k));
	main_imsg_compose_rde(IMSG_IFINFO, 0, &kif->k, sizeof(kif->k));
}

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

	ifan = msg;

	switch (ifan->ifan_what) {
	case IFAN_ARRIVAL:
		if ((kif = calloc(1, sizeof(struct kif_node))) == NULL) {
			log_warn("if_announce");
			return;
		}

		kif->k.ifindex = ifan->ifan_index;
		strlcpy(kif->k.ifname, ifan->ifan_name, sizeof(kif->k.ifname));
		kif_insert(kif);
		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 {
		struct rt_msghdr	hdr;
		struct sockaddr_in	prefix;
		struct sockaddr_in	nexthop;
		struct sockaddr_in	mask;
	} r;

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

	bzero(&r, sizeof(r));
	r.hdr.rtm_msglen = sizeof(r);
	r.hdr.rtm_version = RTM_VERSION;
	r.hdr.rtm_type = action;
	r.hdr.rtm_flags = RTF_PROTO2;
	r.hdr.rtm_seq = kr_state.rtseq++;	/* overflow doesn't matter */
	r.hdr.rtm_addrs = RTA_DST|RTA_GATEWAY|RTA_NETMASK;
	r.prefix.sin_len = sizeof(r.prefix);
	r.prefix.sin_family = AF_INET;
	r.prefix.sin_addr.s_addr = kroute->prefix.s_addr;

	r.nexthop.sin_len = sizeof(r.nexthop);
	r.nexthop.sin_family = AF_INET;
	r.nexthop.sin_addr.s_addr = kroute->nexthop.s_addr;
	if (kroute->nexthop.s_addr != 0)
		r.hdr.rtm_flags |= RTF_GATEWAY;

	r.mask.sin_len = sizeof(r.mask);
	r.mask.sin_family = AF_INET;
	r.mask.sin_addr.s_addr = prefixlen2mask(kroute->prefixlen);

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

	return (0);
}

int
fetchtable(void)
{
	size_t			 len;
	int			 mib[6];
	char			*buf, *next, *lim;
	struct rt_msghdr	*rtm;
	struct sockaddr		*sa, *rti_info[RTAX_MAX];
	struct sockaddr_in	*sa_in;
	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;

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

#ifdef RTF_MPATH
		if (rtm->rtm_flags & RTF_MPATH)		/* multipath */
			continue;
#endif

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

		if (!(rtm->rtm_flags & RTF_PROTO1))
			kr->r.flags = F_KERNEL;

		switch (sa->sa_family) {
		case AF_INET:
			kr->r.prefix.s_addr =
			    ((struct sockaddr_in *)sa)->sin_addr.s_addr;
			sa_in = (struct sockaddr_in *)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 (sa_in != NULL) {
				if (sa_in->sin_len == 0)
					break;
				kr->r.prefixlen =
				    mask2prefixlen(sa_in->sin_addr.s_addr);
			} else if (rtm->rtm_flags & RTF_HOST)
				kr->r.prefixlen = 32;
			else
				kr->r.prefixlen =
				    prefixlen_classful(kr->r.prefix.s_addr);
			break;
		default:
			free(kr);
			continue;
		}

		kr->r.ifindex = rtm->rtm_index;
		if ((sa = rti_info[RTAX_GATEWAY]) != NULL)
			switch (sa->sa_family) {
			case AF_INET:
				kr->r.nexthop.s_addr =
				    ((struct sockaddr_in *)sa)->sin_addr.s_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
			kroute_insert(kr);

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

int
fetchifs(int ifindex)
{
	size_t			 len;
	int			 mib[6];
	char			*buf, *next, *lim;
	struct if_msghdr	 ifm;
	struct kif_node		*kif;
	struct sockaddr		*sa, *rti_info[RTAX_MAX];
	struct sockaddr_dl	*sdl;

	mib[0] = CTL_NET;
	mib[1] = AF_ROUTE;
	mib[2] = 0;
	mib[3] = AF_INET;
	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 += ifm.ifm_msglen) {
		memcpy(&ifm, next, sizeof(ifm));
		if (ifm.ifm_type != RTM_IFINFO)
			continue;

		sa = (struct sockaddr *)(next + sizeof(ifm));
		get_rtaddrs(ifm.ifm_addrs, sa, rti_info);

		if ((kif = calloc(1, sizeof(struct kif_node))) == NULL) {
			log_warn("fetchifs");
			free(buf);
			return (-1);
		}

		kif->k.ifindex = ifm.ifm_index;
		kif->k.flags = ifm.ifm_flags;
		kif->k.link_state = ifm.ifm_data.ifi_link_state;
		kif->k.media_type = ifm.ifm_data.ifi_type;
		kif->k.baudrate = ifm.ifm_data.ifi_baudrate;
		kif->k.mtu = ifm.ifm_data.ifi_mtu;
		kif->k.nh_reachable = (kif->k.flags & IFF_UP) &&
		    (ifm.ifm_data.ifi_link_state != LINK_STATE_DOWN);
		if ((sa = rti_info[RTAX_IFP]) != NULL)
			if (sa->sa_family == AF_LINK) {
				sdl = (struct sockaddr_dl *)sa;
				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() */
			}

		kif_insert(kif);
	}
	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 sockaddr		*sa, *rti_info[RTAX_MAX];
	struct sockaddr_in	*sa_in;
	struct kroute_node	*kr;
	struct in_addr		 prefix, nexthop;
	u_int8_t		 prefixlen;
	int			 flags;
	u_short			 ifindex;

	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;
		sa = (struct sockaddr *)(rtm + 1);
		get_rtaddrs(rtm->rtm_addrs, sa, rti_info);

		prefix.s_addr = 0;
		prefixlen = 0;
		flags = F_KERNEL;
		nexthop.s_addr = 0;

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

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

		if (rtm->rtm_type == RTM_ADD || rtm->rtm_type == RTM_CHANGE ||
		    rtm->rtm_type == RTM_DELETE) {
			if (rtm->rtm_flags & RTF_LLINFO)	/* arp cache */
				continue;
			switch (sa->sa_family) {
			case AF_INET:
				prefix.s_addr =
				    ((struct sockaddr_in *)sa)->sin_addr.s_addr;
				sa_in = (struct sockaddr_in *)
				    rti_info[RTAX_NETMASK];
				if (sa_in != NULL) {
					if (sa_in->sin_len != 0)
						prefixlen = mask2prefixlen(
						    sa_in->sin_addr.s_addr);
				} else if (rtm->rtm_flags & RTF_HOST)
					prefixlen = 32;
				else
					prefixlen =
					    prefixlen_classful(prefix.s_addr);
				if (rtm->rtm_flags & RTF_STATIC)
					flags |= F_STATIC;
				if (rtm->rtm_flags & RTF_DYNAMIC)
					flags |= F_DYNAMIC;
				break;
			default:
				continue;
				/* not reached */
			}
		}

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

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

			if ((kr = kroute_find(prefix.s_addr, prefixlen)) !=
			    NULL) {
				if (kr->r.flags & F_KERNEL) {
					kr->r.nexthop.s_addr = nexthop.s_addr;
					kr->r.flags = flags;
					/* just readd, the RDE will care */
					kr_redistribute(IMSG_NETWORK_ADD,
					    &kr->r);
				}
			} else if (rtm->rtm_type == RTM_CHANGE) {
				log_warnx("change req for %s/%u: not "
				    "in table", inet_ntoa(prefix),
				    prefixlen);
				continue;
			} else {
				if ((kr = calloc(1,
				    sizeof(struct kroute_node))) == NULL) {
					log_warn("dispatch_rtmsg");
					return (-1);
				}
				kr->r.prefix.s_addr = prefix.s_addr;
				kr->r.prefixlen = prefixlen;
				kr->r.nexthop.s_addr = nexthop.s_addr;
				kr->r.flags = flags;
				kr->r.ifindex = ifindex;

				kroute_insert(kr);
			}
			break;
		case RTM_DELETE:
			if ((kr = kroute_find(prefix.s_addr, prefixlen)) ==
			    NULL)
				continue;
			if (!(kr->r.flags & F_KERNEL))
				continue;
			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_IFANNOUNCE:
			if_announce(next);
			break;
		default:
			/* ignore for now */
			break;
		}
	}
	return (0);
}