/*-
 * Copyright (c) 2002 Marcel Moolenaar
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * $FreeBSD: src/sys/kern/kern_uuid.c,v 1.13 2007/04/23 12:53:00 pjd Exp $
 */

#include <sys/param.h>
#include <sys/endian.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/kern_syscall.h>
#include <sys/malloc.h>
#include <sys/random.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/sysmsg.h>
#include <sys/uuid.h>
#include <sys/gpt.h>
#include <net/if.h>
#include <net/if_var.h>

/*
 * See also:
 *      http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
 *      http://www.opengroup.org/onlinepubs/009629399/apdxa.htm
 *
 * Note that the generator state is itself an UUID, but the time and clock
 * sequence fields are written in the native byte order.
 */

/* We use an alternative, more convenient representation in the generator. */
struct uuid_private {
        union {
                uint64_t        ll;             /* internal. */
                struct {
                        uint32_t        low;
                        uint16_t        mid;
                        uint16_t        hi;
                } x;
        } time;
        uint16_t        seq;                    /* Big-endian. */
        uint16_t        node[UUID_NODE_LEN>>1];
};

static struct uuid_private uuid_last;

static struct lock uuid_lock;

static
void
uuid_lock_init(void *arg __unused)
{
        lockinit(&uuid_lock, "uuid", 0, 0);
}
SYSINIT(uuid_lock, SI_BOOT1_POST, SI_ORDER_ANY, uuid_lock_init, NULL);

/*
 * Ask the network subsystem for a real MAC address from any of the
 * system interfaces.  If we can't find one, generate a random multicast
 * MAC address.
 */
static void
uuid_node(uint16_t *node)
{
        if (if_getanyethermac(node, UUID_NODE_LEN) != 0)
                read_random(node, UUID_NODE_LEN, 1);
        *((uint8_t*)node) |= 0x01;
}

/*
 * Get the current time as a 60 bit count of 100-nanosecond intervals
 * since 00:00:00.00, October 15,1582. We apply a magic offset to convert
 * the Unix time since 00:00:00.00, January 1, 1970 to the date of the
 * Gregorian reform to the Christian calendar.
 */
static uint64_t
uuid_time(void)
{
        struct timespec ts;
        uint64_t time = 0x01B21DD213814000LL;

        nanotime(&ts);
        time += ts.tv_sec * 10000000LL;         /* 100 ns increments */
        time += ts.tv_nsec / 100;               /* 100 ns increments */
        return (time & ((1LL << 60) - 1LL));    /* limit to 60 bits */
}

struct uuid *
kern_uuidgen(struct uuid *store, size_t count)
{
        struct uuid_private uuid;
        uint64_t time;
        size_t n;

        lockmgr(&uuid_lock, LK_EXCLUSIVE | LK_RETRY);

        uuid_node(uuid.node);
        time = uuid_time();

        if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] ||
            uuid_last.node[1] != uuid.node[1] ||
            uuid_last.node[2] != uuid.node[2]) {
                read_random(&uuid.seq, sizeof(uuid.seq), 1);
                uuid.seq &= 0x3fff;
        } else if (uuid_last.time.ll >= time) {
                uuid.seq = (uuid_last.seq + 1) & 0x3fff;
        } else {
                uuid.seq = uuid_last.seq;
        }

        uuid_last = uuid;
        uuid_last.time.ll = (time + count - 1) & ((1LL << 60) - 1LL);

        lockmgr(&uuid_lock, LK_RELEASE);

        /* Set sequence and variant and deal with byte order. */
        uuid.seq = htobe16(uuid.seq | 0x8000);

        for (n = 0; n < count; n++) {
                /* Set time and version (=1). */
                uuid.time.x.low = (uint32_t)time;
                uuid.time.x.mid = (uint16_t)(time >> 32);
                uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12);
                store[n] = *(struct uuid *)&uuid;
                time++;
        }

        return (store);
}

/*
 * uuidgen(struct uuid *store, int count)
 *
 * Generate an array of new UUIDs
 */
int
sys_uuidgen(struct sysmsg *sysmsg, const struct uuidgen_args *uap)
{
        struct uuid *store;
        size_t count;
        int error;

        /*
         * Limit the number of UUIDs that can be created at the same time
         * to some arbitrary number. This isn't really necessary, but I
         * like to have some sort of upper-bound that's less than 2G :-)
         * XXX probably needs to be tunable.
         */
        if (uap->count < 1 || uap->count > 2048)
                return (EINVAL);

        count = uap->count;
        store = kmalloc(count * sizeof(struct uuid), M_TEMP, M_WAITOK|M_NULLOK);
        if (store == NULL)
                return (ENOSPC);
        kern_uuidgen(store, count);
        error = copyout(store, uap->store, count * sizeof(struct uuid));
        kfree(store, M_TEMP);
        return (error);
}

int
snprintf_uuid(char *buf, size_t sz, struct uuid *uuid)
{
        struct uuid_private *id;
        int cnt;

        id = (struct uuid_private *)uuid;
        cnt = ksnprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x",
            id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq),
            be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2]));
        return (cnt);
}

int
printf_uuid(struct uuid *uuid)
{
        char buf[38];

        snprintf_uuid(buf, sizeof(buf), uuid);
        return (kprintf("%s", buf));
}

int
sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid)
{
        char buf[38];

        snprintf_uuid(buf, sizeof(buf), uuid);
        return (sbuf_printf(sb, "%s", buf));
}

/*
 * Test functions
 */

/* A macro used to improve the readability of uuid_compare(). */
#define DIFF_RETURN(a, b, field)        do {                    \
        if ((a)->field != (b)->field)                           \
                return (((a)->field < (b)->field) ? -1 : 1);    \
} while (0)

/*
 * kuuid_compare() - compare two UUIDs.
 * See also:
 *      http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
 *
 * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller
 *       than any non-nil UUID.
 */
int
kuuid_compare(const struct uuid *a, const struct uuid *b)
{
        int     res;

        /* Deal with NULL or equal pointers. */
        if (a == b)
                return (0);
        if (a == NULL)
                return ((kuuid_is_nil(b)) ? 0 : -1);
        if (b == NULL)
                return ((kuuid_is_nil(a)) ? 0 : 1);

        /* We have to compare the hard way. */
        DIFF_RETURN(a, b, time_low);
        DIFF_RETURN(a, b, time_mid);
        DIFF_RETURN(a, b, time_hi_and_version);
        DIFF_RETURN(a, b, clock_seq_hi_and_reserved);
        DIFF_RETURN(a, b, clock_seq_low);

        res = bcmp(a->node, b->node, sizeof(a->node));
        if (res)
                return ((res < 0) ? -1 : 1);
        return (0);
}

#undef DIFF_RETURN

int
kuuid_is_nil(const struct uuid *uuid)
{
        int i;

        for (i = 0; i < sizeof(*uuid); i += sizeof(int)) {
                if (*(const int *)((const char *)uuid + i) != 0)
                        return(0);
        }
        return(1);
}

int
kuuid_is_ccd(const struct uuid *uuid)
{
        static struct uuid ccd_uuid = GPT_ENT_TYPE_DRAGONFLY_CCD;
        return(kuuid_compare(uuid, &ccd_uuid) == 0);
}

int
kuuid_is_vinum(const struct uuid *uuid)
{
        static struct uuid vinum_uuid = GPT_ENT_TYPE_DRAGONFLY_VINUM;
        return(kuuid_compare(uuid, &vinum_uuid) == 0);
}

/*
 * Encode/Decode UUID into byte-stream.
 *   http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
 *
 * 0                   1                   2                   3
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                          time_low                             |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |       time_mid                |         time_hi_and_version   |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |clk_seq_hi_res |  clk_seq_low  |         node (0-1)            |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                         node (2-5)                            |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

void
le_uuid_enc(void *buf, struct uuid const *uuid)
{
        u_char *p;
        int i;

        p = buf;
        le32enc(p, uuid->time_low);
        le16enc(p + 4, uuid->time_mid);
        le16enc(p + 6, uuid->time_hi_and_version);
        p[8] = uuid->clock_seq_hi_and_reserved;
        p[9] = uuid->clock_seq_low;
        for (i = 0; i < _UUID_NODE_LEN; i++)
                p[10 + i] = uuid->node[i];
}

void
le_uuid_dec(void const *buf, struct uuid *uuid)
{
        u_char const *p;
        int i;

        p = buf;
        uuid->time_low = le32dec(p);
        uuid->time_mid = le16dec(p + 4);
        uuid->time_hi_and_version = le16dec(p + 6);
        uuid->clock_seq_hi_and_reserved = p[8];
        uuid->clock_seq_low = p[9];
        for (i = 0; i < _UUID_NODE_LEN; i++)
                uuid->node[i] = p[10 + i];
}

void
be_uuid_enc(void *buf, struct uuid const *uuid)
{
        u_char *p;
        int i;

        p = buf;
        be32enc(p, uuid->time_low);
        be16enc(p + 4, uuid->time_mid);
        be16enc(p + 6, uuid->time_hi_and_version);
        p[8] = uuid->clock_seq_hi_and_reserved;
        p[9] = uuid->clock_seq_low;
        for (i = 0; i < _UUID_NODE_LEN; i++)
                p[10 + i] = uuid->node[i];
}

void
be_uuid_dec(void const *buf, struct uuid *uuid)
{
        u_char const *p;
        int i;

        p = buf;
        uuid->time_low = be32dec(p);
        uuid->time_mid = le16dec(p + 4);
        uuid->time_hi_and_version = be16dec(p + 6);
        uuid->clock_seq_hi_and_reserved = p[8];
        uuid->clock_seq_low = p[9];
        for (i = 0; i < _UUID_NODE_LEN; i++)
                uuid->node[i] = p[10 + i];
}

int
parse_uuid(const char *str, struct uuid *uuid)
{
        u_int c[11];
        int n;

        /* An empty string represents a nil UUID. */
        if (*str == '\0') {
                bzero(uuid, sizeof(*uuid));
                return (0);
        }

        /* The UUID string representation has a fixed length. */
        if (strlen(str) != 36)
                return (EINVAL);

        /*
         * We only work with "new" UUIDs. New UUIDs have the form:
         *      01234567-89ab-cdef-0123-456789abcdef
         * The so called "old" UUIDs, which we don't support, have the form:
         *      0123456789ab.cd.ef.01.23.45.67.89.ab
         */
        if (str[8] != '-')
                return (EINVAL);

        n = ksscanf(str, "%8x-%4x-%4x-%2x%2x-%2x%2x%2x%2x%2x%2x", c + 0, c + 1,
            c + 2, c + 3, c + 4, c + 5, c + 6, c + 7, c + 8, c + 9, c + 10);
        /* Make sure we have all conversions. */
        if (n != 11)
                return (EINVAL);

        /* Successful scan. Build the UUID. */
        uuid->time_low = c[0];
        uuid->time_mid = c[1];
        uuid->time_hi_and_version = c[2];
        uuid->clock_seq_hi_and_reserved = c[3];
        uuid->clock_seq_low = c[4];
        for (n = 0; n < 6; n++)
                uuid->node[n] = c[n + 5];

        /* Check semantics... */
        return (((c[3] & 0x80) != 0x00 &&               /* variant 0? */
            (c[3] & 0xc0) != 0x80 &&                    /* variant 1? */
            (c[3] & 0xe0) != 0xc0) ? EINVAL : 0);       /* variant 2? */
}