1 /* 2 * Copyright (c) 2002 Marcel Moolenaar 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/endian.h> 31 #include <sys/kernel.h> 32 #include <sys/lock.h> 33 #include <sys/mutex.h> 34 #include <sys/sbuf.h> 35 #include <sys/socket.h> 36 #include <sys/sysproto.h> 37 #include <sys/systm.h> 38 #include <sys/uuid.h> 39 40 #include <net/if.h> 41 #include <net/if_dl.h> 42 #include <net/if_types.h> 43 44 /* 45 * See also: 46 * http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt 47 * http://www.opengroup.org/onlinepubs/009629399/apdxa.htm 48 * 49 * Note that the generator state is itself an UUID, but the time and clock 50 * sequence fields are written in the native byte order. 51 */ 52 53 CTASSERT(sizeof(struct uuid) == 16); 54 55 /* We use an alternative, more convenient representation in the generator. */ 56 struct uuid_private { 57 union { 58 uint64_t ll; /* internal. */ 59 struct { 60 uint32_t low; 61 uint16_t mid; 62 uint16_t hi; 63 } x; 64 } time; 65 uint16_t seq; /* Big-endian. */ 66 uint16_t node[UUID_NODE_LEN>>1]; 67 }; 68 69 CTASSERT(sizeof(struct uuid_private) == 16); 70 71 static struct uuid_private uuid_last; 72 73 static struct mtx uuid_mutex; 74 MTX_SYSINIT(uuid_lock, &uuid_mutex, "UUID generator mutex lock", MTX_DEF); 75 76 /* 77 * Return the first MAC address we encounter or, if none was found, 78 * construct a sufficiently random multicast address. We don't try 79 * to return the same MAC address as previously returned. We always 80 * generate a new multicast address if no MAC address exists in the 81 * system. 82 * It would be nice to know if 'ifnet' or any of its sub-structures 83 * has been changed in any way. If not, we could simply skip the 84 * scan and safely return the MAC address we returned before. 85 */ 86 static void 87 uuid_node(uint16_t *node) 88 { 89 struct ifnet *ifp; 90 struct ifaddr *ifa; 91 struct sockaddr_dl *sdl; 92 int i; 93 94 /* XXX: lock ifnet. */ 95 TAILQ_FOREACH(ifp, &ifnet, if_link) { 96 /* Walk the address list */ 97 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 98 sdl = (struct sockaddr_dl*)ifa->ifa_addr; 99 if (sdl != NULL && sdl->sdl_family == AF_LINK && 100 sdl->sdl_type == IFT_ETHER) { 101 /* Got a MAC address. */ 102 bcopy(LLADDR(sdl), node, UUID_NODE_LEN); 103 /* XXX: unlock ifnet. */ 104 return; 105 } 106 } 107 } 108 /* XXX: unlock ifnet. */ 109 110 for (i = 0; i < (UUID_NODE_LEN>>1); i++) 111 node[i] = (uint16_t)arc4random(); 112 *((uint8_t*)node) |= 0x80; 113 } 114 115 /* 116 * Get the current time as a 60 bit count of 100-nanosecond intervals 117 * since 00:00:00.00, October 15,1582. We apply a magic offset to convert 118 * the Unix time since 00:00:00.00, Januari 1, 1970 to the date of the 119 * Gregorian reform to the Christian calendar. 120 */ 121 static uint64_t 122 uuid_time(void) 123 { 124 struct bintime bt; 125 uint64_t time = 0x01B21DD213814000LL; 126 127 bintime(&bt); 128 time += (uint64_t)bt.sec * 10000000LL; 129 time += (10000000LL * (uint32_t)(bt.frac >> 32)) >> 32; 130 return (time & ((1LL << 60) - 1LL)); 131 } 132 133 #ifndef _SYS_SYSPROTO_H_ 134 struct uuidgen_args { 135 struct uuid *store; 136 int count; 137 }; 138 #endif 139 140 int 141 uuidgen(struct thread *td, struct uuidgen_args *uap) 142 { 143 struct uuid_private uuid; 144 uint64_t time; 145 int error; 146 147 /* 148 * Limit the number of UUIDs that can be created at the same time 149 * to some arbitrary number. This isn't really necessary, but I 150 * like to have some sort of upper-bound that's less than 2G :-) 151 * XXX needs to be tunable. 152 */ 153 if (uap->count < 1 || uap->count > 2048) 154 return (EINVAL); 155 156 /* XXX: pre-validate accessibility to the whole of the UUID store? */ 157 158 mtx_lock(&uuid_mutex); 159 160 uuid_node(uuid.node); 161 time = uuid_time(); 162 163 if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] || 164 uuid_last.node[1] != uuid.node[1] || 165 uuid_last.node[2] != uuid.node[2]) 166 uuid.seq = (uint16_t)arc4random() & 0x3fff; 167 else if (uuid_last.time.ll >= time) 168 uuid.seq = (uuid_last.seq + 1) & 0x3fff; 169 else 170 uuid.seq = uuid_last.seq; 171 172 uuid_last = uuid; 173 uuid_last.time.ll = (time + uap->count - 1) & ((1LL << 60) - 1LL); 174 175 mtx_unlock(&uuid_mutex); 176 177 /* Set sequence and variant and deal with byte order. */ 178 uuid.seq = htobe16(uuid.seq | 0x8000); 179 180 /* XXX: this should copyout larger chunks at a time. */ 181 do { 182 /* Set time and version (=1) and deal with byte order. */ 183 uuid.time.x.low = (uint32_t)time; 184 uuid.time.x.mid = (uint16_t)(time >> 32); 185 uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12); 186 error = copyout(&uuid, uap->store, sizeof(uuid)); 187 uap->store++; 188 uap->count--; 189 time++; 190 } while (uap->count > 0 && !error); 191 192 return (error); 193 } 194 195 int 196 snprintf_uuid(char *buf, size_t sz, struct uuid *uuid) 197 { 198 struct uuid_private *id; 199 int cnt; 200 201 id = (struct uuid_private *)uuid; 202 cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x", 203 id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq), 204 be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2])); 205 return (cnt); 206 } 207 208 int 209 printf_uuid(struct uuid *uuid) 210 { 211 char buf[38]; 212 213 snprintf_uuid(buf, sizeof(buf), uuid); 214 return (printf("%s", buf)); 215 } 216 217 int 218 sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid) 219 { 220 char buf[38]; 221 222 snprintf_uuid(buf, sizeof(buf), uuid); 223 return (sbuf_printf(sb, "%s", buf)); 224 } 225