/*      $FreeBSD: src/sys/netinet6/scope6.c,v 1.1.2.3 2002/04/01 15:29:04 ume Exp $     */
/*      $DragonFly: src/sys/netinet6/scope6.c,v 1.11 2008/01/05 14:02:40 swildner Exp $ */
/*      $KAME: scope6.c,v 1.10 2000/07/24 13:29:31 itojun Exp $ */

/*
 * Copyright (C) 2000 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/systm.h>
#include <sys/queue.h>
#include <sys/thread2.h>

#include <net/route.h>
#include <net/if.h>

#include <netinet/in.h>

#include <netinet6/in6_var.h>
#include <netinet6/scope6_var.h>

static struct scope6_id sid_default;

static __inline
struct scope6_id *
SID(struct ifnet *ifp)
{
        struct in6_ifextra *xtra;

        xtra = ifp->if_afdata[AF_INET6];
        if (xtra)
                return (xtra->scope6_id);
        return(NULL);
}

void
scope6_init(void)
{
        bzero(&sid_default, sizeof(sid_default));
}

struct scope6_id *
scope6_ifattach(struct ifnet *ifp)
{
        struct scope6_id *sid;

        sid = (struct scope6_id *)kmalloc(sizeof(*sid), M_IFADDR,
            M_WAITOK | M_ZERO);

        crit_enter();

        /*
         * XXX: IPV6_ADDR_SCOPE_xxx macros are not standard.
         * Should we rather hardcode here?
         */
        sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = ifp->if_index;
        sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = ifp->if_index;
#ifdef MULTI_SCOPE
        /* by default, we don't care about scope boundary for these scopes. */
        sid->s6id_list[IPV6_ADDR_SCOPE_SITELOCAL] = 1;
        sid->s6id_list[IPV6_ADDR_SCOPE_ORGLOCAL] = 1;
#endif

        crit_exit();
        return sid;
}

void
scope6_ifdetach(struct scope6_id *sid)
{
        kfree(sid, M_IFADDR);
}

int
scope6_set(struct ifnet *ifp, struct scope6_id *idlist)
{
        int i;
        int error = 0;
        struct scope6_id *sid = SID(ifp);

        if (!sid)       /* paranoid? */
                return (EINVAL);

        /*
         * XXX: We need more consistency checks of the relationship among
         * scopes (e.g. an organization should be larger than a site).
         */

        /*
         * TODO(XXX): after setting, we should reflect the changes to
         * interface addresses, routing table entries, PCB entries...
         */

        crit_enter();

        for (i = 0; i < 16; i++) {
                if (idlist->s6id_list[i] &&
                    idlist->s6id_list[i] != sid->s6id_list[i]) {
                        /*
                         * An interface zone ID must be the corresponding
                         * interface index by definition.
                         */
                        if (i == IPV6_ADDR_SCOPE_INTFACELOCAL &&
                            idlist->s6id_list[i] != ifp->if_index) {
                                crit_exit();
                                return (EINVAL);
                        }

                        if (i == IPV6_ADDR_SCOPE_LINKLOCAL &&
                            idlist->s6id_list[i] > if_index) {
                                /*
                                 * XXX: theoretically, there should be no
                                 * relationship between link IDs and interface
                                 * IDs, but we check the consistency for
                                 * safety in later use.
                                 */
                                crit_exit();
                                return (EINVAL);
                        }

                        /*
                         * XXX: we must need lots of work in this case,
                         * but we simply set the new value in this initial
                         * implementation.
                         */
                        sid->s6id_list[i] = idlist->s6id_list[i];
                }
        }
        crit_exit();

        return (error);
}

int
scope6_get(struct ifnet *ifp, struct scope6_id *idlist)
{
        struct scope6_id *sid = SID(ifp);

        if (sid == NULL)        /* paranoid? */
                return (EINVAL);

        *idlist = *sid;

        return (0);
}


/*
 * Get a scope of the address. Node-local, link-local, site-local or global.
 */
int
in6_addrscope(struct in6_addr *addr)
{
        int scope;

        if (addr->s6_addr[0] == 0xfe) {
                scope = addr->s6_addr[1] & 0xc0;

                switch (scope) {
                case 0x80:
                        return IPV6_ADDR_SCOPE_LINKLOCAL;
                        break;
                case 0xc0:
                        return IPV6_ADDR_SCOPE_SITELOCAL;
                        break;
                default:
                        return IPV6_ADDR_SCOPE_GLOBAL; /* just in case */
                        break;
                }
        }


        if (addr->s6_addr[0] == 0xff) {
                scope = addr->s6_addr[1] & 0x0f;

                /*
                 * due to other scope such as reserved,
                 * return scope doesn't work.
                 */
                switch (scope) {
                case IPV6_ADDR_SCOPE_INTFACELOCAL:
                        return IPV6_ADDR_SCOPE_INTFACELOCAL;
                        break;
                case IPV6_ADDR_SCOPE_LINKLOCAL:
                        return IPV6_ADDR_SCOPE_LINKLOCAL;
                        break;
                case IPV6_ADDR_SCOPE_SITELOCAL:
                        return IPV6_ADDR_SCOPE_SITELOCAL;
                        break;
                default:
                        return IPV6_ADDR_SCOPE_GLOBAL;
                        break;
                }
        }

        /*
         * Regard loopback and unspecified addresses as global, since
         * they have no ambiguity.
         */
        if (bcmp(&kin6addr_loopback, addr, sizeof(*addr) - 1) == 0) {
                if (addr->s6_addr[15] == 1) /* loopback */
                        return IPV6_ADDR_SCOPE_LINKLOCAL;
                if (addr->s6_addr[15] == 0) /* unspecified */
                        return IPV6_ADDR_SCOPE_GLOBAL; /* XXX: correct? */
        }

        return IPV6_ADDR_SCOPE_GLOBAL;
}

/*
 * When we introduce the "4+28" split semantics in sin6_scope_id,
 * a 32bit integer is not enough to tell a large ID from an error (-1).
 * So, we intentionally use a large type as the return value.
 */
int
in6_addr2zoneid(struct ifnet *ifp,      /* must not be NULL */
                struct in6_addr *addr,  /* must not be NULL */
                u_int32_t *ret_id)      /* must not be NULL */
{
        int scope;
        u_int32_t zoneid = 0;
        struct scope6_id *sid = SID(ifp);

#ifdef DIAGNOSTIC
        if (sid == NULL) { /* should not happen */
                panic("in6_addr2zoneid: scope array is NULL");
                /* NOTREACHED */
        }
        if (ret_id == NULL) {
                panic("in6_addr2zoneid: return ID is null");
                /* NOTREACHED */
        }
#endif

        /*
         * special case: the loopback address can only belong to a loopback
         * interface.
         */
        if (IN6_IS_ADDR_LOOPBACK(addr)) {
                if (!(ifp->if_flags & IFF_LOOPBACK)) {
                        return (-1);
                } else {
                        *ret_id = 0; /* there's no ambiguity */
                        return (0);
                }
        }

        scope = in6_addrscope(addr);

        switch (scope) {
        case IPV6_ADDR_SCOPE_INTFACELOCAL: /* should be interface index */
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL];
                break;

        case IPV6_ADDR_SCOPE_LINKLOCAL:
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL];
                break;

        case IPV6_ADDR_SCOPE_SITELOCAL:
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_SITELOCAL];
                break;

        case IPV6_ADDR_SCOPE_ORGLOCAL:
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_ORGLOCAL];
                break;

        default:
                zoneid = 0;     /* XXX: treat as global. */
                break;
        }
        *ret_id = zoneid;
        return (0);
}

void
scope6_setdefault(struct ifnet *ifp)    /* note that this might be NULL */
{
        /*
         * Currently, this function just set the default "interfaces"
         * and "links" according to the given interface.
         * We might eventually have to separate the notion of "link" from
         * "interface" and provide a user interface to set the default.
         */
        if (ifp) {
                sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] =
                        ifp->if_index;
                sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] =
                        ifp->if_index;
        } else {
                sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = 0;
                sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = 0;
        }
}

int
scope6_get_default(struct scope6_id *idlist)
{
        *idlist = sid_default;

        return (0);
}

u_int32_t
scope6_addr2default(struct in6_addr *addr)
{
        /*
         * special case: The loopback address should be considered as
         * link-local, but there's no ambiguity in the syntax.
         */
        if (IN6_IS_ADDR_LOOPBACK(addr))
                return (0);

        return (sid_default.s6id_list[in6_addrscope(addr)]);
}

/*
 * Determine the appropriate scope zone ID for in6 and ifp.  If ret_id is
 * non NULL, it is set to the zone ID.  If the zone ID needs to be embedded
  * in the in6_addr structure, in6 will be modified.
 */
int
in6_setscope(struct in6_addr *in6, struct ifnet *ifp, u_int32_t *ret_id)
{
        int scope;
        u_int32_t zoneid = 0;
        struct scope6_id *sid;

        ifnet_serialize_all(ifp);

        sid = SID(ifp);

#ifdef DIAGNOSTIC
        if (sid == NULL) { /* should not happen */
                panic("in6_setscope: scope array is NULL");
                /* NOTREACHED */
        }
#endif

        /*
         * special case: the loopback address can only belong to a loopback
         * interface.
         */
        if (IN6_IS_ADDR_LOOPBACK(in6)) {
                if (!(ifp->if_flags & IFF_LOOPBACK)) {
                        ifnet_deserialize_all(ifp);
                        return (EINVAL);
                } else {
                        if (ret_id != NULL)
                                *ret_id = 0; /* there's no ambiguity */
                        ifnet_deserialize_all(ifp);
                        return (0);
                }
        }

        scope = in6_addrscope(in6);

        switch (scope) {
        case IPV6_ADDR_SCOPE_NODELOCAL: /* should be interface index */
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_NODELOCAL];
                break;

        case IPV6_ADDR_SCOPE_LINKLOCAL:
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL];
                break;

        case IPV6_ADDR_SCOPE_SITELOCAL:
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_SITELOCAL];
                break;

        case IPV6_ADDR_SCOPE_ORGLOCAL:
                zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_ORGLOCAL];
                break;

        default:
                zoneid = 0;     /* XXX: treat as global. */
                break;
        }

        ifnet_deserialize_all(ifp);

        if (ret_id != NULL)
                *ret_id = zoneid;

        if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_NODELOCAL(in6) )
                in6->s6_addr16[1] = htons(zoneid & 0xffff); /* XXX */

        return (0);
}