/* $OpenBSD: uuid.c,v 1.6 2018/04/26 12:42:51 guenther Exp $ */ /* * Copyright (c) 2002, Stockholms Universitet * (Stockholm University, Stockholm Sweden) * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * 3. Neither the name of the university nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * NCS/DCE/AFS/GUID generator * * for more information about DCE UUID, see * * * Note, the Microsoft GUID is a DCE UUID, but it seems like they * folded in the seq num with the node part. That would explain how * the reserved field have a bit pattern 110 when reserved is a 2 bit * field. * * XXX should hash the node address for privacy issues */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "uuid.h" static uint32_t seq_num; static struct timeval last_time; static int32_t counter; static char nodeaddr[6]; enum { UUID_NODE_MULTICAST = 0x80 }; static int time_cmp(struct timeval *tv1, struct timeval *tv2) { if (tv1->tv_sec > tv2->tv_sec) return -1; if (tv1->tv_sec < tv2->tv_sec) return 1; if (tv1->tv_usec > tv2->tv_usec) return -1; if (tv1->tv_usec < tv2->tv_usec) return 1; return 0; } static void get_node_addr(char *addr) { struct ifaddrs *ifa, *ifa0; int found_mac = 0; if (getifaddrs(&ifa0) != 0) ifa0 = NULL; for (ifa = ifa0; ifa != NULL && !found_mac; ifa = ifa->ifa_next) { if (ifa->ifa_addr == NULL) continue; #if IFF_LOOPBACK if (ifa->ifa_flags & IFF_LOOPBACK) continue; #endif switch (ifa->ifa_addr->sa_family) { #ifdef AF_LINK case AF_LINK: { struct sockaddr_dl *dl = (struct sockaddr_dl *)ifa->ifa_addr; switch (dl->sdl_type) { case IFT_ETHER: case IFT_FDDI: if (dl->sdl_alen == 6) { memcpy(addr, LLADDR(dl), 6); found_mac = 1; } } } #endif default: break; } } if (ifa0 != NULL) freeifaddrs(ifa0); if (!found_mac) { /* * Set the multicast bit to make sure we won't collide with an * allocated (mac) address. */ arc4random_buf(addr, 6); addr[0] |= UUID_NODE_MULTICAST; } return; } /* * Creates a new UUID. */ void uuid_create(afsUUID *uuid) { static int uuid_inited = 0; struct timeval tv; int ret, got_time; uint64_t dce_time; if (uuid_inited == 0) { gettimeofday(&last_time, NULL); seq_num = arc4random(); get_node_addr(nodeaddr); uuid_inited = 1; } gettimeofday(&tv, NULL); got_time = 0; do { ret = time_cmp(&tv, &last_time); if (ret < 0) { /* Time went backward, just inc seq_num and be done. * seq_num is 6 + 8 bit field it the uuid, so let it wrap * around. don't let it be zero. */ seq_num = (seq_num + 1) & 0x3fff ; if (seq_num == 0) seq_num++; got_time = 1; counter = 0; last_time = tv; } else if (ret > 0) { /* time went forward, reset counter and be happy */ last_time = tv; counter = 0; got_time = 1; } else { #define UUID_MAX_HZ (1) /* make this bigger fix you have larger tickrate */ #define MULTIPLIER_100_NANO_SEC 10 if (++counter < UUID_MAX_HZ * MULTIPLIER_100_NANO_SEC) got_time = 1; } } while(!got_time); /* * now shift time to dce_time, epoch 00:00:00:00, 15 October 1582 * dce time ends year ~3400, so start to worry now */ dce_time = tv.tv_usec * MULTIPLIER_100_NANO_SEC + counter; dce_time += ((uint64_t)tv.tv_sec) * 10000000; dce_time += (((uint64_t)0x01b21dd2) << 32) + 0x13814000; uuid->time_low = dce_time & 0xffffffff; uuid->time_mid = 0xffff & (dce_time >> 32); uuid->time_hi_and_version = 0x0fff & (dce_time >> 48); uuid->time_hi_and_version |= (1 << 12); uuid->clock_seq_low = seq_num & 0xff; uuid->clock_seq_hi_and_reserved = (seq_num >> 8) & 0x3f; uuid->clock_seq_hi_and_reserved |= 0x80; /* dce variant */ memcpy(uuid->node, nodeaddr, 6); } /* * Converts a UUID from binary representation to a string representation. */ void uuid_to_string(const afsUUID *uuid, char *str, size_t strsz) { snprintf(str, strsz, "%08lx-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x", uuid->time_low, uuid->time_mid, uuid->time_hi_and_version, (unsigned char)uuid->clock_seq_hi_and_reserved, (unsigned char)uuid->clock_seq_low, (unsigned char)uuid->node[0], (unsigned char)uuid->node[1], (unsigned char)uuid->node[2], (unsigned char)uuid->node[3], (unsigned char)uuid->node[4], (unsigned char)uuid->node[5]); } #ifdef TEST int main(int argc, char **argv) { char str[1000]; afsUUID u1, u2; uuid_create(&u1); uuid_to_string(&u1, str, sizeof(str)); printf("u: %s\n", str); if (uuid_from_string(str, &u2)) { printf("failed to parse\n"); return 0; } if (bcmp(&u1, &u2, sizeof(u1)) != 0) printf("u1 != u2\n"); return 0; } #endif