1 /* 2 * dhcpcd - DHCP client daemon 3 * Copyright (c) 2006-2008 Roy Marples <roy (at) marples.name> 4 * All rights reserved 5 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 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 AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #define THIRTY_YEARS_IN_SECONDS 946707779 29 30 #include <errno.h> 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <time.h> 35 #include <unistd.h> 36 37 #include "common.h" 38 #include "duid.h" 39 #include "net.h" 40 41 size_t 42 get_duid(unsigned char *duid, const struct interface *iface) 43 { 44 FILE *f; 45 uint16_t type = 0; 46 uint16_t hw = 0; 47 uint32_t ul; 48 time_t t; 49 int x = 0; 50 unsigned char *p = duid; 51 size_t len = 0; 52 char *line; 53 54 /* If we already have a DUID then use it as it's never supposed 55 * to change once we have one even if the interfaces do */ 56 if ((f = fopen(DUID, "r"))) { 57 while ((line = get_line(f))) { 58 len = hwaddr_aton(NULL, line); 59 if (len && len <= DUID_LEN) { 60 hwaddr_aton(duid, line); 61 break; 62 } 63 len = 0; 64 } 65 fclose(f); 66 if (len) 67 return len; 68 } else { 69 if (errno != ENOENT) 70 return 0; 71 } 72 73 /* No file? OK, lets make one based on our interface */ 74 if (!(f = fopen(DUID, "w"))) 75 return 0; 76 type = htons(1); /* DUI-D-LLT */ 77 memcpy(p, &type, 2); 78 p += 2; 79 hw = htons(iface->family); 80 memcpy(p, &hw, 2); 81 p += 2; 82 /* time returns seconds from jan 1 1970, but DUID-LLT is 83 * seconds from jan 1 2000 modulo 2^32 */ 84 t = time(NULL) - THIRTY_YEARS_IN_SECONDS; 85 ul = htonl(t & 0xffffffff); 86 memcpy(p, &ul, 4); 87 p += 4; 88 /* Finally, add the MAC address of the interface */ 89 memcpy(p, iface->hwaddr, iface->hwlen); 90 p += iface->hwlen; 91 len = p - duid; 92 x = fprintf(f, "%s\n", hwaddr_ntoa(duid, len)); 93 fclose(f); 94 /* Failed to write the duid? scrub it, we cannot use it */ 95 if (x < 1) { 96 len = 0; 97 unlink(DUID); 98 } 99 return len; 100 } 101
