/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Copyright 2017 Sebastian Wiedenroth
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ksynch.h>
#include <sys/kmem.h>
#include <sys/errno.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/cmn_err.h>
#include <sys/strsun.h>
#include <sys/zone.h>
#include <netinet/in.h>
#include <inet/common.h>
#include <inet/ip.h>
#include <inet/ip6.h>
#include <inet/ip6_asp.h>
#include <inet/ip_ire.h>
#include <inet/ip_if.h>
#include <inet/ipclassifier.h>

#define IN6ADDR_MASK128_INIT \
        { 0xffffffffU, 0xffffffffU, 0xffffffffU, 0xffffffffU }
#define IN6ADDR_MASK96_INIT     { 0xffffffffU, 0xffffffffU, 0xffffffffU, 0 }
#define IN6ADDR_MASK32_INIT     { 0xffffffffU, 0, 0, 0 }
#ifdef _BIG_ENDIAN
#define IN6ADDR_MASK16_INIT     { 0xffff0000U, 0, 0, 0 }
#define IN6ADDR_MASK10_INIT     { 0xffc00000U, 0, 0, 0 }
#define IN6ADDR_MASK7_INIT      { 0xfe000000U, 0, 0, 0 }
#else
#define IN6ADDR_MASK16_INIT     { 0x0000ffffU, 0, 0, 0 }
#define IN6ADDR_MASK10_INIT     { 0x0000c0ffU, 0, 0, 0 }
#define IN6ADDR_MASK7_INIT      { 0x000000feU, 0, 0, 0 }
#endif

/*
 * This table is ordered such that longest prefix matches are hit first
 * (longer prefix lengths first).  The last entry must be the "default"
 * entry (::0/0).
 */
static ip6_asp_t default_ip6_asp_table[] = {
        { IN6ADDR_LOOPBACK_INIT,        IN6ADDR_MASK128_INIT,
            "Loopback", 50 },
        { IN6ADDR_ANY_INIT,             IN6ADDR_MASK96_INIT,
            "IPv4_Compatible", 1 },
#ifdef _BIG_ENDIAN
        { { 0, 0, 0x0000ffffU, 0 },     IN6ADDR_MASK96_INIT,
            "IPv4", 35 },
        { { 0x20010000U, 0, 0, 0 },     IN6ADDR_MASK32_INIT,
            "Teredo", 5 },
        { { 0x20020000U, 0, 0, 0 },     IN6ADDR_MASK16_INIT,
            "6to4", 30 },
        { { 0x3ffe0000U, 0, 0, 0 },     IN6ADDR_MASK16_INIT,
            "6bone", 1 },
        { { 0xfec00000U, 0, 0, 0 },     IN6ADDR_MASK10_INIT,
            "Site_Local", 1 },
        { { 0xfc000000U, 0, 0, 0 },     IN6ADDR_MASK7_INIT,
            "ULA", 3 },
#else
        { { 0, 0, 0xffff0000U, 0 },     IN6ADDR_MASK96_INIT,
            "IPv4", 35 },
        { { 0x00000120U, 0, 0, 0 },     IN6ADDR_MASK32_INIT,
            "Teredo", 5 },
        { { 0x00000220U, 0, 0, 0 },     IN6ADDR_MASK16_INIT,
            "6to4", 30 },
        { { 0x0000fe3fU, 0, 0, 0 },     IN6ADDR_MASK16_INIT,
            "6bone", 1 },
        { { 0x0000c0feU, 0, 0, 0 },     IN6ADDR_MASK10_INIT,
            "Site_Local", 1 },
        { { 0x000000fcU, 0, 0, 0 },     IN6ADDR_MASK7_INIT,
            "ULA", 3 },
#endif
        { IN6ADDR_ANY_INIT,             IN6ADDR_ANY_INIT,
            "Default", 40 }
};

/*
 * The IPv6 Default Address Selection policy table.
 * Until someone up above reconfigures the policy table, use the global
 * default.  The table needs no lock since the only way to alter it is
 * through the SIOCSIP6ADDRPOLICY which is exclusive in ip.
 */
static void ip6_asp_copy(ip6_asp_t *, ip6_asp_t *, uint_t);
static void ip6_asp_check_for_updates(ip_stack_t *);

void
ip6_asp_init(ip_stack_t *ipst)
{
        /* Initialize the table lock */
        mutex_init(&ipst->ips_ip6_asp_lock, NULL, MUTEX_DEFAULT, NULL);

        ipst->ips_ip6_asp_table = default_ip6_asp_table;

        ipst->ips_ip6_asp_table_count =
            sizeof (default_ip6_asp_table) / sizeof (ip6_asp_t);
}

void
ip6_asp_free(ip_stack_t *ipst)
{
        if (ipst->ips_ip6_asp_table != default_ip6_asp_table) {
                kmem_free(ipst->ips_ip6_asp_table,
                    ipst->ips_ip6_asp_table_count * sizeof (ip6_asp_t));
                ipst->ips_ip6_asp_table = NULL;
        }
        mutex_destroy(&ipst->ips_ip6_asp_lock);
}

/*
 * Return false if the table is being updated. Else, increment the ref
 * count and return true.
 */
boolean_t
ip6_asp_can_lookup(ip_stack_t *ipst)
{
        mutex_enter(&ipst->ips_ip6_asp_lock);
        if (ipst->ips_ip6_asp_uip) {
                mutex_exit(&ipst->ips_ip6_asp_lock);
                return (B_FALSE);
        }
        IP6_ASP_TABLE_REFHOLD(ipst);
        mutex_exit(&ipst->ips_ip6_asp_lock);
        return (B_TRUE);

}

void
ip6_asp_pending_op(queue_t *q, mblk_t *mp, aspfunc_t func)
{
        conn_t  *connp = Q_TO_CONN(q);
        ip_stack_t *ipst = connp->conn_netstack->netstack_ip;

        ASSERT((mp->b_prev == NULL) && (mp->b_queue == NULL) &&
            (mp->b_next == NULL));
        mp->b_queue = (void *)q;
        mp->b_prev = (void *)func;
        mp->b_next = NULL;

        mutex_enter(&ipst->ips_ip6_asp_lock);
        if (ipst->ips_ip6_asp_pending_ops == NULL) {
                ASSERT(ipst->ips_ip6_asp_pending_ops_tail == NULL);
                ipst->ips_ip6_asp_pending_ops =
                    ipst->ips_ip6_asp_pending_ops_tail = mp;
        } else {
                ipst->ips_ip6_asp_pending_ops_tail->b_next = mp;
                ipst->ips_ip6_asp_pending_ops_tail = mp;
        }
        mutex_exit(&ipst->ips_ip6_asp_lock);
}

static void
ip6_asp_complete_op(ip_stack_t *ipst)
{
        mblk_t          *mp;
        queue_t         *q;
        aspfunc_t       func;

        mutex_enter(&ipst->ips_ip6_asp_lock);
        while (ipst->ips_ip6_asp_pending_ops != NULL) {
                mp = ipst->ips_ip6_asp_pending_ops;
                ipst->ips_ip6_asp_pending_ops = mp->b_next;
                mp->b_next = NULL;
                if (ipst->ips_ip6_asp_pending_ops == NULL)
                        ipst->ips_ip6_asp_pending_ops_tail = NULL;
                mutex_exit(&ipst->ips_ip6_asp_lock);

                q = (queue_t *)mp->b_queue;
                func = (aspfunc_t)mp->b_prev;

                mp->b_prev = NULL;
                mp->b_queue = NULL;


                (*func)(NULL, q, mp, NULL);
                mutex_enter(&ipst->ips_ip6_asp_lock);
        }
        mutex_exit(&ipst->ips_ip6_asp_lock);
}

/*
 * Decrement reference count. When it gets to 0, we check for (pending)
 * saved update to the table, if any.
 */
void
ip6_asp_table_refrele(ip_stack_t *ipst)
{
        IP6_ASP_TABLE_REFRELE(ipst);
}

/*
 * This function is guaranteed never to return a NULL pointer.  It
 * will always return information from one of the entries in the
 * asp_table (which will never be empty).  If a pointer is passed
 * in for the precedence, the precedence value will be set; a
 * pointer to the label will be returned by the function.
 *
 * Since the table is only anticipated to have about 10 entries
 * total, the lookup algorithm hasn't been optimized to anything
 * better than O(n).
 */
char *
ip6_asp_lookup(const in6_addr_t *addr, uint32_t *precedence, ip_stack_t *ipst)
{
        ip6_asp_t *aspp;
        ip6_asp_t *match = NULL;
        ip6_asp_t *default_policy;

        aspp = ipst->ips_ip6_asp_table;
        /* The default entry must always be the last one */
        default_policy = aspp + ipst->ips_ip6_asp_table_count - 1;

        while (match == NULL) {
                if (aspp == default_policy) {
                        match = aspp;
                } else {
                        if (V6_MASK_EQ(*addr, aspp->ip6_asp_mask,
                            aspp->ip6_asp_prefix))
                                match = aspp;
                        else
                                aspp++;
                }
        }

        if (precedence != NULL)
                *precedence = match->ip6_asp_precedence;
        return (match->ip6_asp_label);
}

/*
 * If we had deferred updating the table because of outstanding references,
 * do it now. Note, we don't do error checking on the queued IOCTL mblk, since
 * ip_sioctl_ip6addrpolicy() has already done it for us.
 */
void
ip6_asp_check_for_updates(ip_stack_t *ipst)
{
        ip6_asp_t *table;
        size_t  table_size;
        mblk_t  *data_mp, *mp;
        struct iocblk *iocp;

        mutex_enter(&ipst->ips_ip6_asp_lock);
        if (ipst->ips_ip6_asp_pending_update == NULL ||
            ipst->ips_ip6_asp_refcnt > 0) {
                mutex_exit(&ipst->ips_ip6_asp_lock);
                return;
        }

        mp = ipst->ips_ip6_asp_pending_update;
        ipst->ips_ip6_asp_pending_update = NULL;
        ASSERT(mp->b_prev != NULL);

        ipst->ips_ip6_asp_uip = B_TRUE;

        iocp = (struct iocblk *)mp->b_rptr;
        data_mp = mp->b_cont;
        if (data_mp == NULL) {
                table = NULL;
                table_size = iocp->ioc_count;
        } else {
                table = (ip6_asp_t *)data_mp->b_rptr;
                table_size = iocp->ioc_count;
        }

        ip6_asp_replace(mp, table, table_size, B_TRUE, ipst,
            iocp->ioc_flag & IOC_MODELS);
}

/*
 * ip6_asp_replace replaces the contents of the IPv6 address selection
 * policy table with those specified in new_table.  If new_table is NULL,
 * this indicates that the caller wishes ip to use the default policy
 * table.  The caller is responsible for making sure that there are exactly
 * new_count policy entries in new_table.
 */
/*ARGSUSED5*/
void
ip6_asp_replace(mblk_t *mp, ip6_asp_t *new_table, size_t new_size,
    boolean_t locked, ip_stack_t *ipst, model_t datamodel)
{
        int                     ret_val = 0;
        ip6_asp_t               *tmp_table;
        uint_t                  count;
        queue_t                 *q;
        struct iocblk           *iocp;
#if defined(_SYSCALL32_IMPL) && _LONG_LONG_ALIGNMENT_32 == 4
        size_t ip6_asp_size = SIZEOF_STRUCT(ip6_asp, datamodel);
#else
        const size_t ip6_asp_size = sizeof (ip6_asp_t);
#endif

        if (new_size % ip6_asp_size != 0) {
                ip1dbg(("ip6_asp_replace: invalid table size\n"));
                ret_val = EINVAL;
                if (locked)
                        goto unlock_end;
                goto replace_end;
        } else {
                count = new_size / ip6_asp_size;
        }


        if (!locked)
                mutex_enter(&ipst->ips_ip6_asp_lock);
        /*
         * Check if we are in the process of creating any IRE using the
         * current information. If so, wait till that is done.
         */
        if (!locked && ipst->ips_ip6_asp_refcnt > 0) {
                /* Save this request for later processing */
                if (ipst->ips_ip6_asp_pending_update == NULL) {
                        ipst->ips_ip6_asp_pending_update = mp;
                } else {
                        /* Let's not queue multiple requests for now */
                        ip1dbg(("ip6_asp_replace: discarding request\n"));
                        mutex_exit(&ipst->ips_ip6_asp_lock);
                        ret_val =  EAGAIN;
                        goto replace_end;
                }
                mutex_exit(&ipst->ips_ip6_asp_lock);
                return;
        }

        /* Prevent lookups till the table have been updated */
        if (!locked)
                ipst->ips_ip6_asp_uip = B_TRUE;

        ASSERT(ipst->ips_ip6_asp_refcnt == 0);

        if (new_table == NULL) {
                /*
                 * This is a special case.  The user wants to revert
                 * back to using the default table.
                 */
                if (ipst->ips_ip6_asp_table == default_ip6_asp_table)
                        goto unlock_end;

                kmem_free(ipst->ips_ip6_asp_table,
                    ipst->ips_ip6_asp_table_count * sizeof (ip6_asp_t));
                ipst->ips_ip6_asp_table = default_ip6_asp_table;
                ipst->ips_ip6_asp_table_count =
                    sizeof (default_ip6_asp_table) / sizeof (ip6_asp_t);
                goto unlock_end;
        }

        if (count == 0) {
                ret_val = EINVAL;
                ip1dbg(("ip6_asp_replace: empty table\n"));
                goto unlock_end;
        }

        if ((tmp_table = kmem_alloc(count * sizeof (ip6_asp_t), KM_NOSLEEP)) ==
            NULL) {
                ret_val = ENOMEM;
                goto unlock_end;
        }

#if defined(_SYSCALL32_IMPL) && _LONG_LONG_ALIGNMENT_32 == 4

        /*
         * If 'new_table' -actually- originates from a 32-bit process
         * then the nicely aligned ip6_asp_label array will be
         * subtlely misaligned on this kernel, because the structure
         * is 8 byte aligned in the kernel, but only 4 byte aligned in
         * userland.  Fix it up here.
         *
         * XX64 See the notes in ip_sioctl_ip6addrpolicy.  Perhaps we could
         *      do the datamodel transformation (below) there instead of here?
         */
        if (datamodel == IOC_ILP32) {
                ip6_asp_t *dst;
                ip6_asp32_t *src;
                int i;

                if ((dst = kmem_zalloc(count * sizeof (*dst),
                    KM_NOSLEEP)) == NULL) {
                        kmem_free(tmp_table, count * sizeof (ip6_asp_t));
                        ret_val = ENOMEM;
                        goto unlock_end;
                }

                /*
                 * Copy each element of the table from ip6_asp32_t
                 * format into ip6_asp_t format.  Fortunately, since
                 * we're just dealing with a trailing structure pad,
                 * we can do this straightforwardly with a flurry of
                 * bcopying.
                 */
                src = (void *)new_table;
                for (i = 0; i < count; i++)
                        bcopy(src + i, dst + i, sizeof (*src));

                ip6_asp_copy(dst, tmp_table, count);
                kmem_free(dst, count * sizeof (*dst));
        } else
#endif
                ip6_asp_copy(new_table, tmp_table, count);

        /* Make sure the last entry is the default entry */
        if (!IN6_IS_ADDR_UNSPECIFIED(&tmp_table[count - 1].ip6_asp_prefix) ||
            !IN6_IS_ADDR_UNSPECIFIED(&tmp_table[count - 1].ip6_asp_mask)) {
                ret_val = EINVAL;
                kmem_free(tmp_table, count * sizeof (ip6_asp_t));
                ip1dbg(("ip6_asp_replace: bad table: no default entry\n"));
                goto unlock_end;
        }
        if (ipst->ips_ip6_asp_table != default_ip6_asp_table) {
                kmem_free(ipst->ips_ip6_asp_table,
                    ipst->ips_ip6_asp_table_count * sizeof (ip6_asp_t));
        }
        ipst->ips_ip6_asp_table = tmp_table;
        ipst->ips_ip6_asp_table_count = count;

unlock_end:
        ipst->ips_ip6_asp_uip = B_FALSE;
        mutex_exit(&ipst->ips_ip6_asp_lock);

        /* Let conn_ixa caching know that source address selection changed */
        ip_update_source_selection(ipst);

replace_end:
        /* Reply to the ioctl */
        q = (queue_t *)mp->b_prev;
        mp->b_prev = NULL;
        if (q == NULL) {
                freemsg(mp);
                goto check_binds;
        }
        iocp = (struct iocblk *)mp->b_rptr;
        iocp->ioc_error = ret_val;
        iocp->ioc_count = 0;
        DB_TYPE(mp) = (iocp->ioc_error == 0) ? M_IOCACK : M_IOCNAK;
        qreply(q, mp);
check_binds:
        ip6_asp_complete_op(ipst);
}

/*
 * Copies the contents of src_table to dst_table, and sorts the
 * entries in decending order of prefix lengths.  It assumes that both
 * tables are appropriately sized to contain count entries.
 */
static void
ip6_asp_copy(ip6_asp_t *src_table, ip6_asp_t *dst_table, uint_t count)
{
        ip6_asp_t *src_ptr, *src_limit, *dst_ptr, *dst_limit, *dp;

        dst_table[0] = src_table[0];
        if (count == 1)
                return;

        /*
         * Sort the entries in descending order of prefix lengths.
         *
         * Note: this should be a small table.  In 99% of cases, we
         * expect the table to have 9 entries.  In the remaining 1%
         * of cases, we expect the table to have one or two more
         * entries.
         */
        src_limit = src_table + count;
        dst_limit = dst_table + 1;
        for (src_ptr = src_table + 1; src_ptr != src_limit;
            src_ptr++, dst_limit++) {
                for (dst_ptr = dst_table; dst_ptr < dst_limit; dst_ptr++) {
                        if (ip_mask_to_plen_v6(&src_ptr->ip6_asp_mask) >
                            ip_mask_to_plen_v6(&dst_ptr->ip6_asp_mask)) {
                                /*
                                 * Make room to insert the source entry
                                 * before dst_ptr by shifting entries to
                                 * the right.
                                 */
                                for (dp = dst_limit - 1; dp >= dst_ptr; dp--)
                                        *(dp + 1) = *dp;
                                break;
                        }
                }
                *dst_ptr = *src_ptr;
        }
}

/*
 * This function copies as many entries from ip6_asp_table as will fit
 * into dtable.  The dtable_size parameter is the size of dtable
 * in bytes.  This function returns the number of entries in
 * ip6_asp_table, even if it's not able to fit all of the entries into
 * dtable.
 */
int
ip6_asp_get(ip6_asp_t *dtable, size_t dtable_size, ip_stack_t *ipst)
{
        uint_t dtable_count;

        if (dtable != NULL) {
                if (dtable_size < sizeof (ip6_asp_t))
                        return (-1);

                dtable_count = dtable_size / sizeof (ip6_asp_t);
                bcopy(ipst->ips_ip6_asp_table, dtable,
                    MIN(ipst->ips_ip6_asp_table_count, dtable_count) *
                    sizeof (ip6_asp_t));
        }

        return (ipst->ips_ip6_asp_table_count);
}

/*
 * Compare two labels.  Return B_TRUE if they are equal, B_FALSE
 * otherwise.
 */
boolean_t
ip6_asp_labelcmp(const char *label1, const char *label2)
{
        int64_t *llptr1, *llptr2;

        /*
         * The common case, the two labels are actually the same string
         * from the policy table.
         */
        if (label1 == label2)
                return (B_TRUE);

        /*
         * Since we know the labels are at most 16 bytes long, compare
         * the two strings as two 8-byte long integers.  The ip6_asp_t
         * structure guarantees that the labels are 8 byte alligned.
         */
        llptr1 = (int64_t *)label1;
        llptr2 = (int64_t *)label2;
        if (llptr1[0] == llptr2[0] && llptr1[1] == llptr2[1])
                return (B_TRUE);
        return (B_FALSE);
}