/*
 *  Copyright (c) 1998 by the University of Southern California.
 *  All rights reserved.
 *
 *  Permission to use, copy, modify, and distribute this software and
 *  its documentation in source and binary forms for lawful
 *  purposes and without fee is hereby granted, provided
 *  that the above copyright notice appear in all copies and that both
 *  the copyright notice and this permission notice appear in supporting
 *  documentation, and that any documentation, advertising materials,
 *  and other materials related to such distribution and use acknowledge
 *  that the software was developed by the University of Southern
 *  California and/or Information Sciences Institute.
 *  The name of the University of Southern California may not
 *  be used to endorse or promote products derived from this software
 *  without specific prior written permission.
 *
 *  THE UNIVERSITY OF SOUTHERN CALIFORNIA DOES NOT MAKE ANY REPRESENTATIONS
 *  ABOUT THE SUITABILITY OF THIS SOFTWARE FOR ANY PURPOSE.  THIS SOFTWARE IS
 *  PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
 *  INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND
 *  NON-INFRINGEMENT.
 *
 *  IN NO EVENT SHALL USC, OR ANY OTHER CONTRIBUTOR BE LIABLE FOR ANY
 *  SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER IN CONTRACT,
 *  TORT, OR OTHER FORM OF ACTION, ARISING OUT OF OR IN CONNECTION WITH,
 *  THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 *  Other copyrights might apply to parts of this software and are so
 *  noted when applicable.
 */
/*
 *  Questions concerning this software should be directed to
 *  Mickael Hoerdt (hoerdt@clarinet.u-strasbg.fr) LSIIT Strasbourg.
 *
 */
/*
 * This program has been derived from pim6dd.        
 * The pim6dd program is covered by the license in the accompanying file
 * named "LICENSE.pim6dd".
 */
/*
 * This program has been derived from pimd.        
 * The pimd program is covered by the license in the accompanying file
 * named "LICENSE.pimd".
 *
 */
/*
 * Part of this program has been derived from mrouted.
 * The mrouted program is covered by the license in the accompanying file
 * named "LICENSE.mrouted".
 *
 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
 * Leland Stanford Junior University.
 *
 * $FreeBSD$
 */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "defs.h"
#include <sys/socket.h>
#include <net/route.h>
#ifdef HAVE_ROUTING_SOCKETS
#include <net/if_dl.h>
#endif
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include "vif.h"
#include "debug.h"
#include "routesock.h"

#ifdef HAVE_ROUTING_SOCKETS
union sockunion
{
    struct sockaddr sa;
    struct sockaddr_in6 sin6;
    struct sockaddr_dl sdl;
}               so_dst, so_ifp;
typedef union sockunion *sup;
int             routing_socket;
int             rtm_addrs,
                pid;
struct rt_metrics rt_metrics;
u_long          rtm_inits;

/*
 * Local functions definitions.
 */
static int getmsg 
__P((register struct rt_msghdr *, int,
     struct rpfctl * rpfinfo));

/*
 * TODO: check again!
 */
#ifdef IRIX
#define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) \
		    : sizeof(__uint64_t))
#else
#define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
		    : sizeof(long))
#endif				/* IRIX */

#ifdef HAVE_SA_LEN
#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
#else
#define ADVANCE(x, n) (x += ROUNDUP(4))	/* TODO: a hack!! */
#endif

/* Open and initialize the routing socket */
int
init_routesock()
{
    pid = getpid();
    routing_socket = socket(PF_ROUTE, SOCK_RAW, AF_INET6);
    if (routing_socket < 0)
    {
	log(LOG_ERR, 0, "\nRouting socket error");
	return -1;
    }
    if (fcntl(routing_socket, F_SETFL, O_NONBLOCK) == -1)
    {
	log(LOG_ERR, 0, "\n Routing socket error");
	return -1;
    }
// TODO : UTILITY ?
#if 0
    {
	int             off;

	off = 0;
	if (setsockopt(routing_socket, SOL_SOCKET,
		       SO_USELOOPBACK, (char *) &off,
		       sizeof(off)) < 0)
	{
	    log(LOG_ERR, 0, "\n setsockopt(SO_USELOOPBACK,0)");
	    return -1;
	}
    }
#endif
    return 0;
}


struct
{
    struct rt_msghdr m_rtm;
    char            m_space[512];
}               m_rtmsg;


/* get the rpf neighbor info */
int
k_req_incoming(source, rpfp)
    struct sockaddr_in6 *source;
    struct rpfctl  *rpfp;
{
    int             flags = RTF_STATIC;
    register sup    su;
    static int      seq;
    int             rlen;
    register char  *cp = m_rtmsg.m_space;
    register int    l;
    struct rpfctl   rpfinfo;

    /* TODO: a hack!!!! */
#ifdef HAVE_SA_LEN
#define NEXTADDR(w, u) \
    if (rtm_addrs & (w)) { \
	l = ROUNDUP(u.sa.sa_len); bcopy((char *)&(u), cp, l); cp += l;\
    }
#else
#define NEXTADDR(w, u) \
    if (rtm_addrs & (w)) { \
	l = ROUNDUP(4); bcopy((char *)&(u), cp, l); cp += l;\
    }
#endif				/* HAVE_SA_LEN */

    /* initialize */
    memset(&rpfp->rpfneighbor, 0, sizeof(rpfp->rpfneighbor));
    rpfp->source = *source;

    /*
     * check if local address or directly connected before calling the
     * routing socket
     */

    if ((rpfp->iif = find_vif_direct_local(source)) != NO_VIF)
    {
	rpfp->rpfneighbor = *source;
	return (TRUE);
    }

    /* prepare the routing socket params */
    rtm_addrs |= RTA_DST;
    rtm_addrs |= RTA_IFP;
    su = &so_dst;
    su->sin6.sin6_family = AF_INET6;
#ifdef HAVE_SA_LEN
    su->sin6.sin6_len = sizeof(struct sockaddr_in6);
#endif
    su->sin6.sin6_addr = source->sin6_addr;
    su->sin6.sin6_scope_id = source->sin6_scope_id;
    so_ifp.sa.sa_family = AF_LINK;
#ifdef HAVE_SA_LEN
    so_ifp.sa.sa_len = sizeof(struct sockaddr_dl);
#endif
    flags |= RTF_UP;
    flags |= RTF_HOST;
    flags |= RTF_GATEWAY;
    errno = 0;
    bzero((char *) &m_rtmsg, sizeof(m_rtmsg));

#define rtm m_rtmsg.m_rtm
    rtm.rtm_type = RTM_GET;
    rtm.rtm_flags = flags;
    rtm.rtm_version = RTM_VERSION;
    rtm.rtm_seq = ++seq;
    rtm.rtm_addrs = rtm_addrs;
    rtm.rtm_rmx = rt_metrics;
    rtm.rtm_inits = rtm_inits;

    NEXTADDR(RTA_DST, so_dst);
    NEXTADDR(RTA_IFP, so_ifp);
    rtm.rtm_msglen = l = cp - (char *) &m_rtmsg;

    if ((rlen = write(routing_socket, (char *) &m_rtmsg, l)) < 0)
    {
	IF_DEBUG(DEBUG_RPF | DEBUG_KERN)
	{
	    if (errno == ESRCH)
		log(LOG_DEBUG, 0,
		    "Writing to routing socket: no such route\n");
	    else
		log(LOG_DEBUG, 0, "Error writing to routing socket");
	}
	return (FALSE);
    }

    do
    {
	l = read(routing_socket, (char *) &m_rtmsg, sizeof(m_rtmsg));
    } while (l > 0 && (rtm.rtm_seq != seq || rtm.rtm_pid != pid));

    if (l < 0)
    {
	IF_DEBUG(DEBUG_RPF | DEBUG_KERN)
	    log(LOG_DEBUG, 0, "Read from routing socket failed: %s", strerror(errno));
	return (FALSE);
    }

    if (getmsg(&rtm, l, &rpfinfo))
    {
	rpfp->rpfneighbor = rpfinfo.rpfneighbor;
	rpfp->iif = rpfinfo.iif;
    }
#undef rtm
    return (TRUE);
}


/*
 * Returns TRUE on success, FALSE otherwise. rpfinfo contains the result.
 */
int
getmsg(rtm, msglen, rpfinfop)
    register struct rt_msghdr *rtm;
    int             msglen;
    struct rpfctl  *rpfinfop;
{
    struct sockaddr *dst = NULL,
                   *gate = NULL,
                   *mask = NULL;
					
    struct sockaddr_dl *ifp = NULL;
    register struct sockaddr *sa;
    register char  *cp;
    register int    i;
    struct sockaddr_in6 *sin6;
    vifi_t          vifi;
    struct uvif    *v;
    char            in6txt[INET6_ADDRSTRLEN];

    if (rpfinfop == (struct rpfctl *) NULL)
	return (FALSE);

    sin6 = (struct sockaddr_in6 *) & so_dst;
    IF_DEBUG(DEBUG_RPF)
	log(LOG_DEBUG, 0, "route to: %s",
	    inet_ntop(AF_INET6, &sin6->sin6_addr, in6txt, INET6_ADDRSTRLEN));
    cp = ((char *) (rtm + 1));
    if (rtm->rtm_addrs)
	for (i = 1; i; i <<= 1)
	    if (i & rtm->rtm_addrs)
	    {
		sa = (struct sockaddr *) cp;
		switch (i)
		{
		case RTA_DST:
		    dst = sa;
		    break;
		case RTA_GATEWAY:
		    gate = sa;
		    break;
		case RTA_NETMASK:
		    mask = sa;
		    break;
		case RTA_IFP:
		    if (sa->sa_family == AF_LINK &&
			((struct sockaddr_dl *) sa)->sdl_nlen)
			ifp = (struct sockaddr_dl *) sa;
		    break;
#if 0
	 	default:
			/*
			 * There are some defined flags other than above 4,
			 * but we are not interested in them.
			 */
			log(LOG_WARNING, 0,
			    "Routesock.c (getmsg) unknown flag : %d",i);
#endif
		}
		ADVANCE(cp, sa);
	    }

    if (!ifp)
    {				/* No incoming interface */
	IF_DEBUG(DEBUG_RPF)
	    log(LOG_DEBUG, 0,
		"No incoming interface for destination %s",
	   inet_ntop(AF_INET6, &sin6->sin6_addr, in6txt, INET6_ADDRSTRLEN));
	return (FALSE);
    }
    if (dst && mask)
	mask->sa_family = dst->sa_family;
    if (dst)
    {
	sin6 = (struct sockaddr_in6 *) dst;
	IF_DEBUG(DEBUG_RPF)
	    log(LOG_DEBUG, 0, " destination is: %s",
	   inet_ntop(AF_INET6, &sin6->sin6_addr, in6txt, INET6_ADDRSTRLEN));
    }

    if (gate && rtm->rtm_flags & RTF_GATEWAY)
    {
	sin6 = (struct sockaddr_in6 *) gate;
	IF_DEBUG(DEBUG_RPF)
	    log(LOG_DEBUG, 0, " gateway is: %s",
	   inet_ntop(AF_INET6, &sin6->sin6_addr, in6txt, INET6_ADDRSTRLEN));
	rpfinfop->rpfneighbor = *sin6;

	if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
	{
#if 0
	    rpfinfop->rpfneighbor.sin6_scope_id =
		ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
#endif
	    rpfinfop->rpfneighbor.sin6_scope_id = ifp->sdl_index;
	    /*
	     * XXX: KAME kernel embeds the interface index to the address.
	     * Clear the index for safety.
	     */
	    rpfinfop->rpfneighbor.sin6_addr.s6_addr[2] = 0;
	    rpfinfop->rpfneighbor.sin6_addr.s6_addr[3] = 0;
	}
    }

    for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v)
	/* get the number of the interface by matching the name */
	if ((strlen(v->uv_name) == ifp->sdl_nlen) &&
	    !(strncmp(v->uv_name,ifp->sdl_data,ifp->sdl_nlen)))
	    break;

    IF_DEBUG(DEBUG_RPF)
	log(LOG_DEBUG, 0, " iif is %d", vifi);

    rpfinfop->iif = vifi;

    if (vifi >= numvifs)
    {
	IF_DEBUG(DEBUG_RPF)
	    log(LOG_DEBUG, 0,
		"Invalid incoming interface for destination %s, because of invalid virtual interface",
	   inet_ntop(AF_INET6, &sin6->sin6_addr, in6txt, INET6_ADDRSTRLEN));
	return (FALSE);		/* invalid iif */
    }

    return (TRUE);
}


#else				/* HAVE_ROUTING_SOCKETS */


/*
 * Return in rpfcinfo the incoming interface and the next hop router toward
 * source.
 */
/* TODO: check whether next hop router address is in network or host order */
int
k_req_incoming(source, rpfcinfo)
    struct sockaddr_in6 *source;
    struct rpfctl  *rpfcinfo;
{
    rpfcinfo->source = *source;
    rpfcinfo->iif = NO_VIF;	/* just initialized, will be */
    /* changed in kernel */
    memset(&rpfcinfo->rpfneighbor, 0, sizeof(rpfcinfo->rpfneighbor));	/* initialized */

    if (ioctl(udp_socket, SIOCGETRPF, (char *) rpfcinfo) < 0)
    {
	log(LOG_ERR, errno, "ioctl SIOCGETRPF k_req_incoming");
	return (FALSE);
    }
    return (TRUE);
}

#endif				/* HAVE_ROUTING_SOCKETS */