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/uuid.h> 38 39 #include <net/if.h> 40 #include <net/if_dl.h> 41 #include <net/if_types.h> 42 43 /* 44 * See also: 45 * http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt 46 * http://www.opengroup.org/onlinepubs/009629399/apdxa.htm 47 * 48 * Note that the generator state is itself an UUID, but the time and clock 49 * sequence fields are written in the native byte order. 50 */ 51 52 CTASSERT(sizeof(struct uuid) == 16); 53 54 /* We use an alternative, more convenient representation in the generator. */ 55 struct uuid_private { 56 union { 57 uint64_t ll; /* internal. */ 58 struct { 59 uint32_t low; 60 uint16_t mid; 61 uint16_t hi; 62 } x; 63 } time; 64 uint16_t seq; /* Big-endian. */ 65 uint16_t node[UUID_NODE_LEN>>1]; 66 }; 67 68 CTASSERT(sizeof(struct uuid_private) == 16); 69 70 static struct uuid_private uuid_last; 71 72 static struct mtx uuid_mutex; 73 MTX_SYSINIT(uuid_lock, &uuid_mutex, "UUID generator mutex lock", MTX_DEF); 74 75 /* 76 * Return the first MAC address we encounter or, if none was found, 77 * construct a sufficiently random multicast address. We don't try 78 * to return the same MAC address as previously returned. We always 79 * generate a new multicast address if no MAC address exists in the 80 * system. 81 * It would be nice to know if 'ifnet' or any of its sub-structures 82 * has been changed in any way. If not, we could simply skip the 83 * scan and safely return the MAC address we returned before. 84 */ 85 static void 86 uuid_node(uint16_t *node) 87 { 88 struct ifnet *ifp; 89 struct ifaddr *ifa; 90 struct sockaddr_dl *sdl; 91 int i; 92 93 /* XXX: lock ifnet. */ 94 TAILQ_FOREACH(ifp, &ifnet, if_link) { 95 /* Walk the address list */ 96 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 97 sdl = (struct sockaddr_dl*)ifa->ifa_addr; 98 if (sdl != NULL && sdl->sdl_family == AF_LINK && 99 sdl->sdl_type == IFT_ETHER) { 100 /* Got a MAC address. */ 101 bcopy(LLADDR(sdl), node, UUID_NODE_LEN); 102 /* XXX: unlock ifnet. */ 103 return; 104 } 105 } 106 } 107 /* XXX: unlock ifnet. */ 108 109 for (i = 0; i < (UUID_NODE_LEN>>1); i++) 110 node[i] = (uint16_t)arc4random(); 111 *((uint8_t*)node) |= 0x80; 112 } 113 114 /* 115 * Get the current time as a 60 bit count of 100-nanosecond intervals 116 * since 00:00:00.00, October 15,1582. We apply a magic offset to convert 117 * the Unix time since 00:00:00.00, Januari 1, 1970 to the date of the 118 * Gregorian reform to the Christian calendar. 119 */ 120 static uint64_t 121 uuid_time(void) 122 { 123 struct bintime bt; 124 uint64_t time = 0x01B21DD213814000LL; 125 126 bintime(&bt); 127 time += (uint64_t)bt.sec * 10000000LL; 128 time += (10000000LL * (uint32_t)(bt.frac >> 32)) >> 32; 129 return (time & ((1LL << 60) - 1LL)); 130 } 131 132 #ifndef _SYS_SYSPROTO_H_ 133 struct uuidgen_args { 134 struct uuid *store; 135 int count; 136 }; 137 #endif 138 139 int 140 uuidgen(struct thread *td, struct uuidgen_args *uap) 141 { 142 struct uuid_private uuid; 143 uint64_t time; 144 int error; 145 146 /* 147 * Limit the number of UUIDs that can be created at the same time 148 * to some arbitrary number. This isn't really necessary, but I 149 * like to have some sort of upper-bound that's less than 2G :-) 150 * XXX needs to be tunable. 151 */ 152 if (uap->count < 1 || uap->count > 2048) 153 return (EINVAL); 154 155 /* XXX: pre-validate accessibility to the whole of the UUID store? */ 156 157 mtx_lock(&uuid_mutex); 158 159 uuid_node(uuid.node); 160 time = uuid_time(); 161 162 if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] || 163 uuid_last.node[1] != uuid.node[1] || 164 uuid_last.node[2] != uuid.node[2]) 165 uuid.seq = (uint16_t)arc4random() & 0x3fff; 166 else if (uuid_last.time.ll >= time) 167 uuid.seq = (uuid_last.seq + 1) & 0x3fff; 168 else 169 uuid.seq = uuid_last.seq; 170 171 uuid_last = uuid; 172 uuid_last.time.ll = (time + uap->count - 1) & ((1LL << 60) - 1LL); 173 174 mtx_unlock(&uuid_mutex); 175 176 /* Set sequence and variant and deal with byte order. */ 177 uuid.seq = htobe16(uuid.seq | 0x8000); 178 179 /* XXX: this should copyout larger chunks at a time. */ 180 do { 181 /* Set time and version (=1) and deal with byte order. */ 182 uuid.time.x.low = (uint32_t)time; 183 uuid.time.x.mid = (uint16_t)(time >> 32); 184 uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12); 185 error = copyout(&uuid, uap->store, sizeof(uuid)); 186 uap->store++; 187 uap->count--; 188 time++; 189 } while (uap->count > 0 && !error); 190 191 return (error); 192 } 193 194 int 195 snprintf_uuid(char *buf, size_t sz, struct uuid *uuid) 196 { 197 struct uuid_private *id; 198 int cnt; 199 200 id = (struct uuid_private *)uuid; 201 cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x", 202 id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq), 203 be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2])); 204 return (cnt); 205 } 206 207 int 208 printf_uuid(struct uuid *uuid) 209 { 210 char buf[38]; 211 212 snprintf_uuid(buf, sizeof(buf), uuid); 213 return (printf("%s", buf)); 214 } 215 216 int 217 sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid) 218 { 219 char buf[38]; 220 221 snprintf_uuid(buf, sizeof(buf), uuid); 222 return (sbuf_printf(sb, "%s", buf)); 223 } 224