kern_uuid.c

Go to the documentation of this file.

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * 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.
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include <sys/param.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/jail.h>
#include <sys/uuid.h>
 
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/vnet.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.
 */
 
CTASSERT(sizeof(struct uuid) == 16);
 
/* We use an alternative, more convenient representation in the generator. */
struct uuid_private {
        union {
                uint64_t        ll;     /* internal, for uuid_last only */
                struct {
                        uint32_t        low;
                        uint16_t        mid;
                        uint16_t        hi;
                } x;
        } time;
        uint16_t        seq;                    /* Big-endian. */
        uint16_t        node[UUID_NODE_LEN>>1];
};
 
CTASSERT(sizeof(struct uuid_private) == 16);
 
struct uuid_macaddr {
        uint16_t        state;
#define UUID_ETHER_EMPTY        0
#define UUID_ETHER_RANDOM       1
#define UUID_ETHER_UNIQUE       2
        uint16_t        node[UUID_NODE_LEN>>1];
};
 
static struct uuid_private uuid_last;
 
#define UUID_NETHER     4
static struct uuid_macaddr uuid_ether[UUID_NETHER];
 
static struct mtx uuid_mutex;
MTX_SYSINIT(uuid_lock, &uuid_mutex, "UUID generator mutex lock", MTX_DEF);
 
/*
 * Return the first MAC address added in the array. If it's empty, then
 * construct a sufficiently random multicast MAC address first. Any
 * addresses added later will bump the random MAC address up tp the next
 * index.
 */
static void
uuid_node(uint16_t *node)
{
        int i;
 
        if (uuid_ether[0].state == UUID_ETHER_EMPTY) {
                for (i = 0; i < (UUID_NODE_LEN>>1); i++)
                        uuid_ether[0].node[i] = (uint16_t)arc4random();
                *((uint8_t*)uuid_ether[0].node) |= 0x01;
                uuid_ether[0].state = UUID_ETHER_RANDOM;
        }
        for (i = 0; i < (UUID_NODE_LEN>>1); i++)
                node[i] = uuid_ether[0].node[i];
}
 
/*
 * 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 bintime bt;
        uint64_t time = 0x01B21DD213814000LL;
 
        bintime(&bt);
        time += (uint64_t)bt.sec * 10000000LL;
        time += (10000000LL * (uint32_t)(bt.frac >> 32)) >> 32;
        return (time & ((1LL << 60) - 1LL));
}
 
struct uuid *
kern_uuidgen(struct uuid *store, size_t count)
{
        struct uuid_private uuid;
        uint64_t time;
        size_t n;
 
        mtx_lock(&uuid_mutex);
 
        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])
                uuid.seq = (uint16_t)arc4random() & 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);
 
        mtx_unlock(&uuid_mutex);
 
        /* 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);
}
 
#ifndef _SYS_SYSPROTO_H_
struct uuidgen_args {
        struct uuid *store;
        int     count;
};
#endif
int
sys_uuidgen(struct thread *td, 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 = malloc(count * sizeof(struct uuid), M_TEMP, M_WAITOK);
        kern_uuidgen(store, count);
        error = copyout(store, uap->store, count * sizeof(struct uuid));
        free(store, M_TEMP);
        return (error);
}
 
int
uuid_ether_add(const uint8_t *addr)
{
        int i, sum;
 
        /*
         * Validate input. No multicast (flag 0x1), no locally administered
         * (flag 0x2) and no 'all-zeroes' addresses.
         */
        if (addr[0] & 0x03)
                return (EINVAL);
        sum = 0;
        for (i = 0; i < UUID_NODE_LEN; i++)
                sum += addr[i];
        if (sum == 0)
                return (EINVAL);
 
        mtx_lock(&uuid_mutex);
 
        /* Make sure the MAC isn't known already and that there's space. */
        i = 0;
        while (i < UUID_NETHER && uuid_ether[i].state == UUID_ETHER_UNIQUE) {
                if (!bcmp(addr, uuid_ether[i].node, UUID_NODE_LEN)) {
                        mtx_unlock(&uuid_mutex);
                        return (EEXIST);
                }
                i++;
        }
        if (i == UUID_NETHER) {
                mtx_unlock(&uuid_mutex);
                return (ENOSPC);
        }
 
        /* Insert MAC at index, moving the non-empty entry if possible. */
        if (uuid_ether[i].state == UUID_ETHER_RANDOM && i < UUID_NETHER - 1)
                uuid_ether[i + 1] = uuid_ether[i];
        uuid_ether[i].state = UUID_ETHER_UNIQUE;
        bcopy(addr, uuid_ether[i].node, UUID_NODE_LEN);
        mtx_unlock(&uuid_mutex);
        return (0);
}
 
int
uuid_ether_del(const uint8_t *addr)
{
        int i;
 
        mtx_lock(&uuid_mutex);
        i = 0;
        while (i < UUID_NETHER && uuid_ether[i].state == UUID_ETHER_UNIQUE &&
            bcmp(addr, uuid_ether[i].node, UUID_NODE_LEN))
                i++;
        if (i == UUID_NETHER || uuid_ether[i].state != UUID_ETHER_UNIQUE) {
                mtx_unlock(&uuid_mutex);
                return (ENOENT);
        }
 
        /* Remove it by shifting higher index entries down. */
        while (i < UUID_NETHER - 1 && uuid_ether[i].state != UUID_ETHER_EMPTY) {
                uuid_ether[i] = uuid_ether[i + 1];
                i++;
        }
        if (uuid_ether[i].state != UUID_ETHER_EMPTY) {
                uuid_ether[i].state = UUID_ETHER_EMPTY;
                bzero(uuid_ether[i].node, UUID_NODE_LEN);
        }
        mtx_unlock(&uuid_mutex);
        return (0);
}
 
int
snprintf_uuid(char *buf, size_t sz, struct uuid *uuid)
{
        struct uuid_private *id;
        int cnt;
 
        id = (struct uuid_private *)uuid;
        cnt = snprintf(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 (printf("%s", buf));
}
 
int
sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid)
{
        char buf[38];
 
        snprintf_uuid(buf, sizeof(buf), uuid);
        return (sbuf_cat(sb, buf));
}
 
/*
 * 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 = be16dec(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
validate_uuid(const char *str, size_t size, struct uuid *uuid, int flags)
{
        u_int c[11];
        int n;
 
        if (size == 0 || *str == '\0') {
                /* An empty string may represent a nil UUID. */
                if ((flags & VUUIDF_EMPTYOK) != 0) {
                        if (uuid != NULL)
                                bzero(uuid, sizeof(*uuid));
                        return (0);
                }
 
                return (EINVAL);
        }
 
        /* The UUID string representation has a fixed length. */
        if (size != 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);
 
        /* Now check the format. */
        n = sscanf(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 if requested. */
        if (uuid != NULL) {
                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];
        }
 
        if ((flags & VUUIDF_CHECKSEMANTICS) == 0)
                return (0);
 
        return (((c[3] & 0x80) != 0x00 &&               /* variant 0? */
            (c[3] & 0xc0) != 0x80 &&                    /* variant 1? */
            (c[3] & 0xe0) != 0xc0) ? EINVAL : 0);       /* variant 2? */
}
 
#define VUUIDF_PARSEFLAGS       (VUUIDF_EMPTYOK | VUUIDF_CHECKSEMANTICS)
 
int
parse_uuid(const char *str, struct uuid *uuid)
{
 
        return (validate_uuid(str, strlen(str), uuid, VUUIDF_PARSEFLAGS));
}
 
int
uuidcmp(const struct uuid *uuid1, const struct uuid *uuid2)
{
 
        return (memcmp(uuid1, uuid2, sizeof(struct uuid)));
}