1 | /* |
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2 | * dhcpcd - DHCP client daemon |
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3 | * Copyright (c) 2006-2013 Roy Marples <roy@marples.name> |
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4 | * All rights reserved |
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5 | |
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6 | * Redistribution and use in source and binary forms, with or without |
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7 | * modification, are permitted provided that the following conditions |
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8 | * are met: |
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9 | * 1. Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * 2. Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * |
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15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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16 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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17 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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18 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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19 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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20 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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21 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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22 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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23 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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24 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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25 | * SUCH DAMAGE. |
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26 | */ |
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27 | |
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28 | #define DUID_TIME_EPOCH 946684800 |
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29 | #define DUID_LLT 1 |
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30 | #define DUID_LL 3 |
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31 | |
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32 | #include <sys/socket.h> |
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33 | #include <sys/types.h> |
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34 | |
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35 | #include <net/if.h> |
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36 | #include <net/if_arp.h> |
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37 | |
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38 | #include <errno.h> |
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39 | #include <stdio.h> |
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40 | #include <stdlib.h> |
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41 | #include <string.h> |
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42 | #include <syslog.h> |
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43 | #include <time.h> |
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44 | #include <unistd.h> |
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45 | |
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46 | #ifndef ARPHRD_NETROM |
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47 | # define ARPHRD_NETROM 0 |
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48 | #endif |
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49 | |
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50 | #include "common.h" |
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51 | #include "duid.h" |
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52 | #include "net.h" |
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53 | |
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54 | unsigned char *duid = NULL; |
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55 | size_t duid_len = 0; |
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56 | |
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57 | static size_t |
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58 | duid_make(unsigned char *d, const struct interface *ifp, uint16_t type) |
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59 | { |
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60 | unsigned char *p; |
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61 | uint16_t u16; |
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62 | time_t t; |
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63 | uint32_t u32; |
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64 | |
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65 | p = d; |
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66 | u16 = htons(type); |
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67 | memcpy(p, &u16, 2); |
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68 | p += 2; |
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69 | u16 = htons(ifp->family); |
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70 | memcpy(p, &u16, 2); |
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71 | p += 2; |
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72 | if (type == DUID_LLT) { |
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73 | /* time returns seconds from jan 1 1970, but DUID-LLT is |
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74 | * seconds from jan 1 2000 modulo 2^32 */ |
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75 | t = time(NULL) - DUID_TIME_EPOCH; |
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76 | u32 = htonl(t & 0xffffffff); |
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77 | memcpy(p, &u32, 4); |
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78 | p += 4; |
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79 | } |
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80 | /* Finally, add the MAC address of the interface */ |
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81 | memcpy(p, ifp->hwaddr, ifp->hwlen); |
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82 | p += ifp->hwlen; |
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83 | return p - d; |
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84 | } |
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85 | |
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86 | static size_t |
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87 | duid_get(unsigned char *d, const struct interface *ifp) |
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88 | { |
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89 | FILE *f; |
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90 | int x = 0; |
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91 | size_t len = 0; |
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92 | char *line; |
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93 | const struct interface *ifp2; |
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94 | |
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95 | /* If we already have a DUID then use it as it's never supposed |
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96 | * to change once we have one even if the interfaces do */ |
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97 | if ((f = fopen(DUID, "r"))) { |
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98 | while ((line = get_line(f))) { |
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99 | len = hwaddr_aton(NULL, line); |
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100 | if (len && len <= DUID_LEN) { |
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101 | hwaddr_aton(d, line); |
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102 | break; |
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103 | } |
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104 | len = 0; |
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105 | } |
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106 | fclose(f); |
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107 | if (len) |
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108 | return len; |
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109 | } else { |
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110 | if (errno != ENOENT) |
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111 | syslog(LOG_ERR, "error reading DUID: %s: %m", DUID); |
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112 | } |
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113 | |
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114 | /* No file? OK, lets make one based on our interface */ |
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115 | if (ifp->family == ARPHRD_NETROM) { |
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116 | syslog(LOG_WARNING, "%s: is a NET/ROM psuedo interface", |
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117 | ifp->name); |
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118 | TAILQ_FOREACH(ifp2, ifaces, next) { |
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119 | if (ifp2->family != ARPHRD_NETROM) |
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120 | break; |
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121 | } |
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122 | if (ifp2) { |
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123 | ifp = ifp2; |
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124 | syslog(LOG_WARNING, |
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125 | "picked interface %s to generate a DUID", |
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126 | ifp->name); |
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127 | } else { |
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128 | syslog(LOG_WARNING, |
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129 | "no interfaces have a fixed hardware address"); |
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130 | return duid_make(d, ifp, DUID_LL); |
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131 | } |
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132 | } |
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133 | |
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134 | if (!(f = fopen(DUID, "w"))) { |
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135 | syslog(LOG_ERR, "error writing DUID: %s: %m", DUID); |
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136 | return duid_make(d, ifp, DUID_LL); |
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137 | } |
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138 | len = duid_make(d, ifp, DUID_LLT); |
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139 | x = fprintf(f, "%s\n", hwaddr_ntoa(d, len)); |
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140 | fclose(f); |
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141 | /* Failed to write the duid? scrub it, we cannot use it */ |
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142 | if (x < 1) { |
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143 | syslog(LOG_ERR, "error writing DUID: %s: %m", DUID); |
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144 | unlink(DUID); |
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145 | return duid_make(d, ifp, DUID_LL); |
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146 | } |
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147 | return len; |
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148 | } |
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149 | |
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150 | size_t duid_init(const struct interface *ifp) |
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151 | { |
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152 | |
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153 | if (duid == NULL) { |
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154 | duid = malloc(DUID_LEN); |
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155 | if (duid == NULL) { |
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156 | syslog(LOG_ERR, "%s: %m", __func__); |
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157 | return 0; |
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158 | } |
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159 | duid_len = duid_get(duid, ifp); |
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160 | } |
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161 | return duid_len; |
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162 | } |
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