1/* 2 * gen_uuid.c --- generate a DCE-compatible uuid 3 * 4 * Copyright (C) 1996, 1997, 1998, 1999 Theodore Ts'o. 5 * 6 * %Begin-Header% 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 * 1. Redistributions of source code must retain the above copyright 11 * notice, and the entire permission notice in its entirety, 12 * including the disclaimer of warranties. 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 * 3. The name of the author may not be used to endorse or promote 17 * products derived from this software without specific prior 18 * written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED 21 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF 23 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE 24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 27 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 28 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 30 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH 31 * DAMAGE. 32 * %End-Header% 33 */ 34 35/* 36 * Force inclusion of SVID stuff since we need it if we're compiling in 37 * gcc-wall wall mode 38 */ 39#define _SVID_SOURCE 40 41#ifdef HAVE_UNISTD_H 42#include <unistd.h> 43#endif 44#ifdef HAVE_STDLIB_H 45#include <stdlib.h> 46#endif 47#include <string.h> 48#include <fcntl.h> 49#include <errno.h> 50#include <sys/types.h> 51#include <sys/time.h> 52#include <sys/stat.h> 53#include <sys/file.h> 54#ifdef HAVE_SYS_IOCTL_H 55#include <sys/ioctl.h> 56#endif 57#ifdef HAVE_SYS_SOCKET_H 58#include <sys/socket.h> 59#endif 60#ifdef HAVE_SYS_SOCKIO_H 61#include <sys/sockio.h> 62#endif 63#ifdef HAVE_NET_IF_H 64#include <net/if.h> 65#endif 66#ifdef HAVE_NETINET_IN_H 67#include <netinet/in.h> 68#endif 69#ifdef HAVE_NET_IF_DL_H 70#include <net/if_dl.h> 71#endif 72 73#include "uuidP.h" 74 75#define get_random_bytes(a,b) arc4random_buf((a),(b)) 76 77/* 78 * Get the ethernet hardware address, if we can find it... 79 */ 80static int get_node_id(unsigned char *node_id) 81{ 82#ifdef HAVE_NET_IF_H 83 int sd; 84 struct ifreq ifr, *ifrp; 85 struct ifconf ifc; 86 char buf[1024]; 87 int n, i; 88 unsigned char *a; 89#ifdef AF_LINK 90 struct sockaddr_dl *sdlp; 91#endif 92 93/* 94 * BSD 4.4 defines the size of an ifreq to be 95 * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len 96 * However, under earlier systems, sa_len isn't present, so the size is 97 * just sizeof(struct ifreq) 98 */ 99#ifdef HAVE_SA_LEN 100#ifndef max 101#define max(a,b) ((a) > (b) ? (a) : (b)) 102#endif 103#define ifreq_size(i) max(sizeof(struct ifreq),\ 104 sizeof((i).ifr_name)+(i).ifr_addr.sa_len) 105#else 106#define ifreq_size(i) sizeof(struct ifreq) 107#endif /* HAVE_SA_LEN*/ 108 109 sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP); 110 if (sd < 0) { 111 return -1; 112 } 113 memset(buf, 0, sizeof(buf)); 114 ifc.ifc_len = sizeof(buf); 115 ifc.ifc_buf = buf; 116 if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) { 117 close(sd); 118 return -1; 119 } 120 n = ifc.ifc_len; 121 for (i = 0; i < n; i+= ifreq_size(*ifrp) ) { 122 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i); 123 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ); 124#ifdef SIOCGIFHWADDR 125 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0) 126 continue; 127 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data; 128#else 129#ifdef SIOCGENADDR 130 if (ioctl(sd, SIOCGENADDR, &ifr) < 0) 131 continue; 132 a = (unsigned char *) ifr.ifr_enaddr; 133#else 134#ifdef AF_LINK 135 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr; 136 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6)) 137 continue; 138 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen]; 139#else 140 /* 141 * XXX we don't have a way of getting the hardware 142 * address 143 */ 144 close(sd); 145 return 0; 146#endif /* AF_LINK */ 147#endif /* SIOCGENADDR */ 148#endif /* SIOCGIFHWADDR */ 149 /* 150 * Skip interfaces that return either 00:00:00:00:00:00 or 151 * 02:00:00:00:00:00. 152 */ 153 if ((!a[0] || a[0] == 0x02) && !a[1] && !a[2] && !a[3] && !a[4] && !a[5]) 154 continue; 155 if (node_id) { 156 memcpy(node_id, a, 6); 157 close(sd); 158 return 1; 159 } 160 } 161 close(sd); 162#endif 163 return 0; 164} 165 166/* Assume that the gettimeofday() has microsecond granularity */ 167#define MAX_ADJUSTMENT 10 168 169static int get_clock(uint32_t *clock_high, uint32_t *clock_low, uint16_t *ret_clock_seq) 170{ 171 static int adjustment = 0; 172 static struct timeval last = {0, 0}; 173 static uint16_t clock_seq; 174 struct timeval tv; 175 unsigned long long clock_reg; 176 177try_again: 178 gettimeofday(&tv, 0); 179 if ((last.tv_sec == 0) && (last.tv_usec == 0)) { 180 get_random_bytes(&clock_seq, sizeof(clock_seq)); 181 clock_seq &= 0x3FFF; 182 last = tv; 183 last.tv_sec--; 184 } 185 if ((tv.tv_sec < last.tv_sec) || 186 ((tv.tv_sec == last.tv_sec) && 187 (tv.tv_usec < last.tv_usec))) { 188 clock_seq = (clock_seq+1) & 0x3FFF; 189 adjustment = 0; 190 last = tv; 191 } else if ((tv.tv_sec == last.tv_sec) && 192 (tv.tv_usec == last.tv_usec)) { 193 if (adjustment >= MAX_ADJUSTMENT) 194 goto try_again; 195 adjustment++; 196 } else { 197 adjustment = 0; 198 last = tv; 199 } 200 201 clock_reg = tv.tv_usec*10 + adjustment; 202 clock_reg += ((unsigned long long) tv.tv_sec)*10000000; 203 clock_reg += (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000; 204 205 *clock_high = clock_reg >> 32; 206 *clock_low = clock_reg; 207 *ret_clock_seq = clock_seq; 208 return 0; 209} 210 211void uuid_generate_time(uuid_t out) 212{ 213 static unsigned char node_id[6]; 214 static int has_init = 0; 215 struct uuid uu; 216 uint32_t clock_mid; 217 218 if (!has_init) { 219 if (get_node_id(node_id) <= 0) { 220 get_random_bytes(node_id, 6); 221 /* 222 * Set multicast bit, to prevent conflicts 223 * with IEEE 802 addresses obtained from 224 * network cards 225 */ 226 node_id[0] |= 0x01; 227 } 228 has_init = 1; 229 } 230 get_clock(&clock_mid, &uu.time_low, &uu.clock_seq); 231 uu.clock_seq |= 0x8000; 232 uu.time_mid = (uint16_t) clock_mid; 233 uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000; 234 memcpy(uu.node, node_id, 6); 235 uuid_pack(&uu, out); 236} 237 238void uuid_generate_random(uuid_t out) 239{ 240 uuid_t buf; 241 struct uuid uu; 242 243 get_random_bytes(buf, sizeof(buf)); 244 uuid_unpack(buf, &uu); 245 246 uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000; 247 uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x4000; 248 uuid_pack(&uu, out); 249} 250 251/* 252 * This is the generic front-end 253 */ 254void uuid_generate(uuid_t out) 255{ 256 uuid_generate_random(out); 257} 258