kern_uuid.c revision 1.11
1 /* $NetBSD: kern_uuid.c,v 1.11 2007/08/26 23:07:16 dyoung Exp $ */ 2 3 /* 4 * Copyright (c) 2002 Marcel Moolenaar 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD: /repoman/r/ncvs/src/sys/kern/kern_uuid.c,v 1.7 2004/01/12 13:34:11 rse Exp $ 29 */ 30 31 #include <sys/cdefs.h> 32 __KERNEL_RCSID(0, "$NetBSD: kern_uuid.c,v 1.11 2007/08/26 23:07:16 dyoung Exp $"); 33 34 #include <sys/param.h> 35 #include <sys/endian.h> 36 #include <sys/kernel.h> 37 #include <sys/mutex.h> 38 #include <sys/socket.h> 39 #include <sys/systm.h> 40 #include <sys/uuid.h> 41 42 /* NetBSD */ 43 #include <sys/proc.h> 44 #include <sys/mount.h> 45 #include <sys/syscallargs.h> 46 #include <sys/uio.h> 47 48 #include <net/if.h> 49 #include <net/if_dl.h> 50 #include <net/if_types.h> 51 52 /* 53 * See also: 54 * http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt 55 * http://www.opengroup.org/onlinepubs/009629399/apdxa.htm 56 * 57 * Note that the generator state is itself an UUID, but the time and clock 58 * sequence fields are written in the native byte order. 59 */ 60 61 /* XXX Do we have a similar ASSERT()? */ 62 #define CTASSERT(x) 63 64 CTASSERT(sizeof(struct uuid) == 16); 65 66 /* We use an alternative, more convenient representation in the generator. */ 67 struct uuid_private { 68 union { 69 uint64_t ll; /* internal. */ 70 struct { 71 uint32_t low; 72 uint16_t mid; 73 uint16_t hi; 74 } x; 75 } time; 76 uint16_t seq; /* Big-endian. */ 77 uint16_t node[UUID_NODE_LEN>>1]; 78 }; 79 80 CTASSERT(sizeof(struct uuid_private) == 16); 81 82 static struct uuid_private uuid_last; 83 84 /* "UUID generator mutex lock" */ 85 static kmutex_t uuid_mutex; 86 87 void 88 uuid_init(void) 89 { 90 91 mutex_init(&uuid_mutex, MUTEX_DEFAULT, IPL_NONE); 92 } 93 94 /* 95 * Return the first MAC address we encounter or, if none was found, 96 * construct a sufficiently random multicast address. We don't try 97 * to return the same MAC address as previously returned. We always 98 * generate a new multicast address if no MAC address exists in the 99 * system. 100 * It would be nice to know if 'ifnet' or any of its sub-structures 101 * has been changed in any way. If not, we could simply skip the 102 * scan and safely return the MAC address we returned before. 103 */ 104 static void 105 uuid_node(uint16_t *node) 106 { 107 struct ifnet *ifp; 108 struct ifaddr *ifa; 109 struct sockaddr_dl *sdl; 110 int i, s; 111 112 s = splnet(); 113 IFNET_FOREACH(ifp) { 114 /* Walk the address list */ 115 IFADDR_FOREACH(ifa, ifp) { 116 sdl = (struct sockaddr_dl*)ifa->ifa_addr; 117 if (sdl != NULL && sdl->sdl_family == AF_LINK && 118 sdl->sdl_type == IFT_ETHER) { 119 /* Got a MAC address. */ 120 memcpy(node, CLLADDR(sdl), UUID_NODE_LEN); 121 splx(s); 122 return; 123 } 124 } 125 } 126 splx(s); 127 128 for (i = 0; i < (UUID_NODE_LEN>>1); i++) 129 node[i] = (uint16_t)arc4random(); 130 *((uint8_t*)node) |= 0x01; 131 } 132 133 /* 134 * Get the current time as a 60 bit count of 100-nanosecond intervals 135 * since 00:00:00.00, October 15,1582. We apply a magic offset to convert 136 * the Unix time since 00:00:00.00, January 1, 1970 to the date of the 137 * Gregorian reform to the Christian calendar. 138 */ 139 /* 140 * At present, NetBSD has no timespec source, only timeval sources. So, 141 * we use timeval. 142 */ 143 static uint64_t 144 uuid_time(void) 145 { 146 struct timeval tv; 147 uint64_t xtime = 0x01B21DD213814000LL; 148 149 microtime(&tv); 150 xtime += (uint64_t)tv.tv_sec * 10000000LL; 151 xtime += (uint64_t)(10 * tv.tv_usec); 152 return (xtime & ((1LL << 60) - 1LL)); 153 } 154 155 /* 156 * Internal routine to actually generate the UUID. 157 */ 158 static void 159 uuid_generate(struct uuid_private *uuid, uint64_t *timep, int count) 160 { 161 uint64_t xtime; 162 163 mutex_enter(&uuid_mutex); 164 165 uuid_node(uuid->node); 166 xtime = uuid_time(); 167 *timep = xtime; 168 169 if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid->node[0] || 170 uuid_last.node[1] != uuid->node[1] || 171 uuid_last.node[2] != uuid->node[2]) 172 uuid->seq = (uint16_t)arc4random() & 0x3fff; 173 else if (uuid_last.time.ll >= xtime) 174 uuid->seq = (uuid_last.seq + 1) & 0x3fff; 175 else 176 uuid->seq = uuid_last.seq; 177 178 uuid_last = *uuid; 179 uuid_last.time.ll = (xtime + count - 1) & ((1LL << 60) - 1LL); 180 181 mutex_exit(&uuid_mutex); 182 } 183 184 int 185 sys_uuidgen(struct lwp *l, void *v, register_t *retval) 186 { 187 struct sys_uuidgen_args *uap = v; 188 struct uuid_private uuid; 189 uint64_t xtime; 190 int error; 191 192 /* 193 * Limit the number of UUIDs that can be created at the same time 194 * to some arbitrary number. This isn't really necessary, but I 195 * like to have some sort of upper-bound that's less than 2G :-) 196 * XXX needs to be tunable. 197 */ 198 if (SCARG(uap,count) < 1 || SCARG(uap,count) > 2048) 199 return (EINVAL); 200 201 /* XXX: pre-validate accessibility to the whole of the UUID store? */ 202 203 /* Generate the base UUID. */ 204 uuid_generate(&uuid, &xtime, SCARG(uap, count)); 205 206 /* Set sequence and variant and deal with byte order. */ 207 uuid.seq = htobe16(uuid.seq | 0x8000); 208 209 /* XXX: this should copyout larger chunks at a time. */ 210 do { 211 /* Set time and version (=1) and deal with byte order. */ 212 uuid.time.x.low = (uint32_t)xtime; 213 uuid.time.x.mid = (uint16_t)(xtime >> 32); 214 uuid.time.x.hi = ((uint16_t)(xtime >> 48) & 0xfff) | (1 << 12); 215 error = copyout(&uuid, SCARG(uap,store), sizeof(uuid)); 216 SCARG(uap, store)++; 217 SCARG(uap, count)--; 218 xtime++; 219 } while (SCARG(uap, count) > 0 && error == 0); 220 221 return (error); 222 } 223 224 int 225 uuid_snprintf(char *buf, size_t sz, const struct uuid *uuid) 226 { 227 const struct uuid_private *id; 228 int cnt; 229 230 id = (const struct uuid_private *)uuid; 231 cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x", 232 id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq), 233 be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2])); 234 return (cnt); 235 } 236 237 int 238 uuid_printf(const struct uuid *uuid) 239 { 240 char buf[UUID_STR_LEN]; 241 242 (void) uuid_snprintf(buf, sizeof(buf), uuid); 243 printf("%s", buf); 244 return (0); 245 } 246 247 /* 248 * Encode/Decode UUID into octet-stream. 249 * http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt 250 * 251 * 0 1 2 3 252 * 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 1 253 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 * | time_low | 255 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 256 * | time_mid | time_hi_and_version | 257 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 258 * |clk_seq_hi_res | clk_seq_low | node (0-1) | 259 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 260 * | node (2-5) | 261 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 262 */ 263 264 void 265 uuid_enc_le(void *buf, const struct uuid *uuid) 266 { 267 uint8_t *p = buf; 268 int i; 269 270 le32enc(p, uuid->time_low); 271 le16enc(p + 4, uuid->time_mid); 272 le16enc(p + 6, uuid->time_hi_and_version); 273 p[8] = uuid->clock_seq_hi_and_reserved; 274 p[9] = uuid->clock_seq_low; 275 for (i = 0; i < _UUID_NODE_LEN; i++) 276 p[10 + i] = uuid->node[i]; 277 } 278 279 void 280 uuid_dec_le(void const *buf, struct uuid *uuid) 281 { 282 const uint8_t *p = buf; 283 int i; 284 285 uuid->time_low = le32dec(p); 286 uuid->time_mid = le16dec(p + 4); 287 uuid->time_hi_and_version = le16dec(p + 6); 288 uuid->clock_seq_hi_and_reserved = p[8]; 289 uuid->clock_seq_low = p[9]; 290 for (i = 0; i < _UUID_NODE_LEN; i++) 291 uuid->node[i] = p[10 + i]; 292 } 293 294 void 295 uuid_enc_be(void *buf, const struct uuid *uuid) 296 { 297 uint8_t *p = buf; 298 int i; 299 300 be32enc(p, uuid->time_low); 301 be16enc(p + 4, uuid->time_mid); 302 be16enc(p + 6, uuid->time_hi_and_version); 303 p[8] = uuid->clock_seq_hi_and_reserved; 304 p[9] = uuid->clock_seq_low; 305 for (i = 0; i < _UUID_NODE_LEN; i++) 306 p[10 + i] = uuid->node[i]; 307 } 308 309 void 310 uuid_dec_be(void const *buf, struct uuid *uuid) 311 { 312 const uint8_t *p = buf; 313 int i; 314 315 uuid->time_low = be32dec(p); 316 uuid->time_mid = le16dec(p + 4); 317 uuid->time_hi_and_version = be16dec(p + 6); 318 uuid->clock_seq_hi_and_reserved = p[8]; 319 uuid->clock_seq_low = p[9]; 320 for (i = 0; i < _UUID_NODE_LEN; i++) 321 uuid->node[i] = p[10 + i]; 322 } 323
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