| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * gen_uuid.c --- generate a DCE-compatible uuid
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| 4 | *
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| 5 | * Copyright (C) 1996, 1997, 1998, 1999 Theodore Ts'o.
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| 6 | *
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| 7 | * %Begin-Header%
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| 8 | * Redistribution and use in source and binary forms, with or without
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| 9 | * modification, are permitted provided that the following conditions
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| 10 | * are met:
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| 11 | * 1. Redistributions of source code must retain the above copyright
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| 12 | * notice, and the entire permission notice in its entirety,
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| 13 | * including the disclaimer of warranties.
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| 14 | * 2. Redistributions in binary form must reproduce the above copyright
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| 15 | * notice, this list of conditions and the following disclaimer in the
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| 16 | * documentation and/or other materials provided with the distribution.
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| 17 | * 3. The name of the author may not be used to endorse or promote
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| 18 | * products derived from this software without specific prior
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| 19 | * written permission.
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| 20 | *
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| 21 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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| 22 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 23 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
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| 24 | * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
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| 25 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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| 26 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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| 27 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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| 28 | * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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| 29 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 30 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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| 31 | * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
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| 32 | * DAMAGE.
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| 33 | * %End-Header%
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| 34 | */
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| 35 |
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| 36 | #include <unistd.h>
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| 37 | #include <stdlib.h>
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| 38 | #include <string.h>
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| 39 | #include <fcntl.h>
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| 40 | #include <errno.h>
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| 41 | #include <sys/types.h>
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| 42 | #include <sys/stat.h>
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| 43 | #include <sys/file.h>
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| 44 | #include <sys/time.h>
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| 45 | #ifdef HAVE_SYS_IOCTL_H
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| 46 | #include <sys/ioctl.h>
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| 47 | #endif
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| 48 | #include <sys/socket.h>
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| 49 | #ifdef HAVE_SYS_SOCKIO_H
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| 50 | #include <sys/sockio.h>
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| 51 | #endif
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| 52 | #ifdef HAVE_NET_IF_H
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| 53 | #include <net/if.h>
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| 54 | #endif
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| 55 | #ifdef HAVE_NETINET_IN_H
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| 56 | #include <netinet/in.h>
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| 57 | #endif
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| 58 | #ifdef HAVE_NET_IF_DL_H
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| 59 | #include <net/if_dl.h>
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| 60 | #endif
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| 61 |
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| 62 | #include "uuidP.h"
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| 63 |
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| 64 | #ifdef HAVE_SRANDOM
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| 65 | #define srand(x) srandom(x)
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| 66 | #define rand() random()
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| 67 | #endif
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| 68 |
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| 69 | static int get_random_fd(void)
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| 70 | {
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| 71 | struct timeval tv;
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| 72 | static int fd = -2;
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| 73 | int i;
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| 74 |
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| 75 | if (fd == -2) {
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| 76 | gettimeofday(&tv, 0);
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| 77 | fd = open("/dev/urandom", O_RDONLY);
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| 78 | if (fd == -1)
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| 79 | fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
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| 80 | srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
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| 81 | }
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| 82 | /* Crank the random number generator a few times */
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| 83 | gettimeofday(&tv, 0);
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| 84 | for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
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| 85 | rand();
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| 86 | return fd;
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| 87 | }
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| 88 |
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| 89 |
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| 90 | /*
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| 91 | * Generate a series of random bytes. Use /dev/urandom if possible,
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| 92 | * and if not, use srandom/random.
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| 93 | */
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| 94 | static void get_random_bytes(void *buf, int nbytes)
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| 95 | {
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| 96 | int i, n = nbytes, fd = get_random_fd();
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| 97 | int lose_counter = 0;
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| 98 | unsigned char *cp = (unsigned char *) buf;
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| 99 |
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| 100 | if (fd >= 0) {
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| 101 | while (n > 0) {
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| 102 | i = read(fd, cp, n);
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| 103 | if (i <= 0) {
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| 104 | if (lose_counter++ > 16)
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| 105 | break;
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| 106 | continue;
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| 107 | }
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| 108 | n -= i;
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| 109 | cp += i;
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| 110 | lose_counter = 0;
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| 111 | }
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| 112 | }
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| 113 |
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| 114 | /*
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| 115 | * We do this all the time, but this is the only source of
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| 116 | * randomness if /dev/random/urandom is out to lunch.
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| 117 | */
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| 118 | for (cp = buf, i = 0; i < nbytes; i++)
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| 119 | *cp++ ^= (rand() >> 7) & 0xFF;
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| 120 | }
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| 121 |
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| 122 | /*
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| 123 | * Get the ethernet hardware address, if we can find it...
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| 124 | */
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| 125 | static int get_node_id(unsigned char *node_id)
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| 126 | {
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| 127 | #ifdef HAVE_NET_IF_H
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| 128 | int sd;
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| 129 | struct ifreq ifr, *ifrp;
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| 130 | struct ifconf ifc;
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| 131 | char buf[1024];
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| 132 | int n, i;
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| 133 | unsigned char *a;
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| 134 | #ifdef HAVE_NET_IF_DL_H
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| 135 | struct sockaddr_dl *sdlp;
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| 136 | #endif
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| 137 |
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| 138 | /*
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| 139 | * BSD 4.4 defines the size of an ifreq to be
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| 140 | * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
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| 141 | * However, under earlier systems, sa_len isn't present, so the size is
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| 142 | * just sizeof(struct ifreq)
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| 143 | */
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| 144 | #ifdef HAVE_SA_LEN
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| 145 | #ifndef max
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| 146 | #define max(a,b) ((a) > (b) ? (a) : (b))
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| 147 | #endif
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| 148 | #define ifreq_size(i) max(sizeof(struct ifreq),\
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| 149 | sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
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| 150 | #else
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| 151 | #define ifreq_size(i) sizeof(struct ifreq)
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| 152 | #endif /* HAVE_SA_LEN*/
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| 153 |
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| 154 | sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
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| 155 | if (sd < 0) {
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| 156 | return -1;
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| 157 | }
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| 158 | memset(buf, 0, sizeof(buf));
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| 159 | ifc.ifc_len = sizeof(buf);
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| 160 | ifc.ifc_buf = buf;
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| 161 | if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
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| 162 | close(sd);
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| 163 | return -1;
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| 164 | }
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| 165 | n = ifc.ifc_len;
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| 166 | for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
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| 167 | ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
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| 168 | strncpy_IFNAMSIZ(ifr.ifr_name, ifrp->ifr_name);
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| 169 | #ifdef SIOCGIFHWADDR
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| 170 | if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
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| 171 | continue;
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| 172 | a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
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| 173 | #else
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| 174 | #ifdef SIOCGENADDR
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| 175 | if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
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| 176 | continue;
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| 177 | a = (unsigned char *) ifr.ifr_enaddr;
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| 178 | #else
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| 179 | #ifdef HAVE_NET_IF_DL_H
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| 180 | sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
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| 181 | if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
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| 182 | continue;
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| 183 | a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
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| 184 | #else
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| 185 | /*
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| 186 | * XXX we don't have a way of getting the hardware
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| 187 | * address
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| 188 | */
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| 189 | close(sd);
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| 190 | return 0;
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| 191 | #endif /* HAVE_NET_IF_DL_H */
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| 192 | #endif /* SIOCGENADDR */
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| 193 | #endif /* SIOCGIFHWADDR */
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| 194 | if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
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| 195 | continue;
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| 196 | if (node_id) {
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| 197 | memcpy(node_id, a, 6);
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| 198 | close(sd);
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| 199 | return 1;
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| 200 | }
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| 201 | }
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| 202 | close(sd);
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| 203 | #endif
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| 204 | return 0;
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| 205 | }
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| 206 |
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| 207 | /* Assume that the gettimeofday() has microsecond granularity */
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| 208 | #define MAX_ADJUSTMENT 10
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| 209 |
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| 210 | static int get_clock(uint32_t *clock_high, uint32_t *clock_low, uint16_t *ret_clock_seq)
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| 211 | {
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| 212 | static int adjustment = 0;
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| 213 | static struct timeval last = {0, 0};
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| 214 | static uint16_t clock_seq;
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| 215 | struct timeval tv;
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| 216 | unsigned long long clock_reg;
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| 217 |
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| 218 | try_again:
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| 219 | gettimeofday(&tv, 0);
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| 220 | if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
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| 221 | get_random_bytes(&clock_seq, sizeof(clock_seq));
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| 222 | clock_seq &= 0x3FFF;
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| 223 | last = tv;
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| 224 | last.tv_sec--;
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| 225 | }
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| 226 | if ((tv.tv_sec < last.tv_sec) ||
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| 227 | ((tv.tv_sec == last.tv_sec) &&
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| 228 | (tv.tv_usec < last.tv_usec))) {
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| 229 | clock_seq = (clock_seq+1) & 0x3FFF;
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| 230 | adjustment = 0;
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| 231 | last = tv;
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| 232 | } else if ((tv.tv_sec == last.tv_sec) &&
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| 233 | (tv.tv_usec == last.tv_usec)) {
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| 234 | if (adjustment >= MAX_ADJUSTMENT)
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| 235 | goto try_again;
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| 236 | adjustment++;
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| 237 | } else {
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| 238 | adjustment = 0;
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| 239 | last = tv;
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| 240 | }
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| 241 |
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| 242 | clock_reg = tv.tv_usec*10 + adjustment;
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| 243 | clock_reg += ((unsigned long long) tv.tv_sec)*10000000;
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| 244 | clock_reg += (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000;
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| 245 |
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| 246 | *clock_high = clock_reg >> 32;
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| 247 | *clock_low = clock_reg;
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| 248 | *ret_clock_seq = clock_seq;
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| 249 | return 0;
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| 250 | }
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| 251 |
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| 252 | void uuid_generate_time(uuid_t out)
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| 253 | {
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| 254 | static unsigned char node_id[6];
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| 255 | static int has_init = 0;
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| 256 | struct uuid uu;
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| 257 | uint32_t clock_mid;
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| 258 |
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| 259 | if (!has_init) {
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| 260 | if (get_node_id(node_id) <= 0) {
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| 261 | get_random_bytes(node_id, 6);
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| 262 | /*
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| 263 | * Set multicast bit, to prevent conflicts
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| 264 | * with IEEE 802 addresses obtained from
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| 265 | * network cards
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| 266 | */
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| 267 | node_id[0] |= 0x01;
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| 268 | }
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| 269 | has_init = 1;
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| 270 | }
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| 271 | get_clock(&clock_mid, &uu.time_low, &uu.clock_seq);
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| 272 | uu.clock_seq |= 0x8000;
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| 273 | uu.time_mid = (uint16_t) clock_mid;
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| 274 | uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
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| 275 | memcpy(uu.node, node_id, 6);
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| 276 | uuid_pack(&uu, out);
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| 277 | }
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| 278 |
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| 279 | void uuid_generate_random(uuid_t out)
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| 280 | {
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| 281 | uuid_t buf;
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| 282 | struct uuid uu;
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| 283 |
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| 284 | get_random_bytes(buf, sizeof(buf));
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| 285 | uuid_unpack(buf, &uu);
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| 286 |
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| 287 | uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
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| 288 | uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x4000;
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| 289 | uuid_pack(&uu, out);
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| 290 | }
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| 291 |
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| 292 | /*
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| 293 | * This is the generic front-end to uuid_generate_random and
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| 294 | * uuid_generate_time. It uses uuid_generate_random only if
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| 295 | * /dev/urandom is available, since otherwise we won't have
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| 296 | * high-quality randomness.
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| 297 | */
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| 298 | void uuid_generate(uuid_t out)
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| 299 | {
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| 300 | if (get_random_fd() >= 0)
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| 301 | uuid_generate_random(out);
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| 302 | else
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| 303 | uuid_generate_time(out);
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| 304 | }
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