1 | /*
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2 | * files.c -- DHCP server file manipulation *
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3 | * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
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4 | */
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5 |
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6 | #include <sys/socket.h>
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7 | #include <arpa/inet.h>
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8 | #include <string.h>
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9 | #include <stdlib.h>
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10 | #include <time.h>
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11 | #include <ctype.h>
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12 | #include <netdb.h>
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13 |
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14 | #include <netinet/ether.h>
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15 | #include "static_leases.h"
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16 |
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17 | #include "dhcpd.h"
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18 | #include "options.h"
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19 | #include "files.h"
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20 | #include "common.h"
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21 |
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22 | /*
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23 | * Domain names may have 254 chars, and string options can be 254
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24 | * chars long. However, 80 bytes will be enough for most, and won't
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25 | * hog up memory. If you have a special application, change it
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26 | */
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27 | #define READ_CONFIG_BUF_SIZE 80
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28 |
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29 | /* on these functions, make sure you datatype matches */
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30 | static int read_ip(const char *line, void *arg)
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31 | {
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32 | struct in_addr *addr = arg;
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33 | struct hostent *host;
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34 | int retval = 1;
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35 |
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36 | if (!inet_aton(line, addr)) {
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37 | if ((host = gethostbyname(line)))
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38 | addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
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39 | else retval = 0;
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40 | }
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41 | return retval;
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42 | }
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43 |
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44 | static int read_mac(const char *line, void *arg)
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45 | {
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46 | uint8_t *mac_bytes = arg;
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47 | struct ether_addr *temp_ether_addr;
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48 | int retval = 1;
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49 |
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50 | temp_ether_addr = ether_aton(line);
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51 |
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52 | if(temp_ether_addr == NULL)
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53 | retval = 0;
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54 | else
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55 | memcpy(mac_bytes, temp_ether_addr, 6);
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56 |
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57 | return retval;
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58 | }
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59 |
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60 |
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61 | static int read_str(const char *line, void *arg)
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62 | {
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63 | char **dest = arg;
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64 |
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65 | free(*dest);
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66 | *dest = strdup(line);
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67 |
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68 | return 1;
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69 | }
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70 |
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71 |
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72 | static int read_u32(const char *line, void *arg)
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73 | {
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74 | uint32_t *dest = arg;
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75 | char *endptr;
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76 | *dest = strtoul(line, &endptr, 0);
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77 | return endptr[0] == '\0';
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78 | }
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79 |
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80 |
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81 | static int read_yn(const char *line, void *arg)
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82 | {
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83 | char *dest = arg;
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84 | int retval = 1;
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85 |
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86 | if (!strcasecmp("yes", line))
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87 | *dest = 1;
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88 | else if (!strcasecmp("no", line))
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89 | *dest = 0;
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90 | else retval = 0;
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91 |
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92 | return retval;
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93 | }
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94 |
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95 |
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96 | /* find option 'code' in opt_list */
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97 | struct option_set *find_option(struct option_set *opt_list, char code)
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98 | {
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99 | while (opt_list && opt_list->data[OPT_CODE] < code)
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100 | opt_list = opt_list->next;
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101 |
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102 | if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
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103 | else return NULL;
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104 | }
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105 |
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106 |
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107 | /* add an option to the opt_list */
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108 | static void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length)
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109 | {
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110 | struct option_set *existing, *new, **curr;
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111 |
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112 | /* add it to an existing option */
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113 | if ((existing = find_option(*opt_list, option->code))) {
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114 | DEBUG(LOG_INFO, "Attaching option %s to existing member of list", option->name);
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115 | if (option->flags & OPTION_LIST) {
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116 | if (existing->data[OPT_LEN] + length <= 255) {
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117 | existing->data = realloc(existing->data,
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118 | existing->data[OPT_LEN] + length + 2);
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119 | memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
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120 | existing->data[OPT_LEN] += length;
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121 | } /* else, ignore the data, we could put this in a second option in the future */
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122 | } /* else, ignore the new data */
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123 | } else {
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124 | DEBUG(LOG_INFO, "Attaching option %s to list", option->name);
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125 |
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126 | /* make a new option */
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127 | new = xmalloc(sizeof(struct option_set));
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128 | new->data = xmalloc(length + 2);
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129 | new->data[OPT_CODE] = option->code;
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130 | new->data[OPT_LEN] = length;
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131 | memcpy(new->data + 2, buffer, length);
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132 |
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133 | curr = opt_list;
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134 | while (*curr && (*curr)->data[OPT_CODE] < option->code)
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135 | curr = &(*curr)->next;
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136 |
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137 | new->next = *curr;
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138 | *curr = new;
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139 | }
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140 | }
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141 |
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142 |
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143 | /* read a dhcp option and add it to opt_list */
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144 | static int read_opt(const char *const_line, void *arg)
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145 | {
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146 | struct option_set **opt_list = arg;
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147 | char *opt, *val, *endptr;
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148 | struct dhcp_option *option;
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149 | int retval = 0, length;
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150 | char buffer[8];
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151 | char *line;
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152 | uint16_t *result_u16 = (uint16_t *) buffer;
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153 | uint32_t *result_u32 = (uint32_t *) buffer;
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154 |
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155 | /* Cheat, the only const line we'll actually get is "" */
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156 | line = (char *) const_line;
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157 | if (!(opt = strtok(line, " \t="))) return 0;
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158 |
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159 | for (option = dhcp_options; option->code; option++)
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160 | if (!strcasecmp(option->name, opt))
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161 | break;
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162 |
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163 | if (!option->code) return 0;
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164 |
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165 | do {
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166 | if (!(val = strtok(NULL, ", \t"))) break;
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167 | length = option_lengths[option->flags & TYPE_MASK];
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168 | retval = 0;
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169 | opt = buffer; /* new meaning for variable opt */
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170 | switch (option->flags & TYPE_MASK) {
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171 | case OPTION_IP:
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172 | retval = read_ip(val, buffer);
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173 | break;
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174 | case OPTION_IP_PAIR:
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175 | retval = read_ip(val, buffer);
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176 | if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
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177 | if (retval) retval = read_ip(val, buffer + 4);
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178 | break;
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179 | case OPTION_STRING:
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180 | length = strlen(val);
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181 | if (length > 0) {
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182 | if (length > 254) length = 254;
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183 | opt = val;
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184 | retval = 1;
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185 | }
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186 | break;
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187 | case OPTION_BOOLEAN:
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188 | retval = read_yn(val, buffer);
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189 | break;
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190 | case OPTION_U8:
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191 | buffer[0] = strtoul(val, &endptr, 0);
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192 | retval = (endptr[0] == '\0');
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193 | break;
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194 | case OPTION_U16:
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195 | *result_u16 = htons(strtoul(val, &endptr, 0));
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196 | retval = (endptr[0] == '\0');
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197 | break;
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198 | case OPTION_S16:
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199 | *result_u16 = htons(strtol(val, &endptr, 0));
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200 | retval = (endptr[0] == '\0');
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201 | break;
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202 | case OPTION_U32:
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203 | *result_u32 = htonl(strtoul(val, &endptr, 0));
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204 | retval = (endptr[0] == '\0');
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205 | break;
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206 | case OPTION_S32:
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207 | *result_u32 = htonl(strtol(val, &endptr, 0));
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208 | retval = (endptr[0] == '\0');
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209 | break;
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210 | default:
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211 | break;
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212 | }
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213 | if (retval)
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214 | attach_option(opt_list, option, opt, length);
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215 | } while (retval && option->flags & OPTION_LIST);
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216 | return retval;
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217 | }
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218 |
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219 | static int read_staticlease(const char *const_line, void *arg)
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220 | {
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221 |
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222 | char *line;
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223 | char *mac_string;
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224 | char *ip_string;
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225 | uint8_t *mac_bytes;
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226 | uint32_t *ip;
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227 |
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228 |
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229 | /* Allocate memory for addresses */
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230 | mac_bytes = xmalloc(sizeof(unsigned char) * 8);
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231 | ip = xmalloc(sizeof(uint32_t));
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232 |
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233 | /* Read mac */
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234 | line = (char *) const_line;
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235 | mac_string = strtok(line, " \t");
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236 | read_mac(mac_string, mac_bytes);
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237 |
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238 | /* Read ip */
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239 | ip_string = strtok(NULL, " \t");
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240 | read_ip(ip_string, ip);
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241 |
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242 | addStaticLease(arg, mac_bytes, ip);
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243 |
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244 | if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
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245 |
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246 | return 1;
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247 |
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248 | }
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249 |
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250 |
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251 | static const struct config_keyword keywords[] = {
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252 | /* keyword handler variable address default */
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253 | {"start", read_ip, &(server_config.start), "192.168.0.20"},
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254 | {"end", read_ip, &(server_config.end), "192.168.0.254"},
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255 | {"interface", read_str, &(server_config.interface), "eth0"},
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256 | {"option", read_opt, &(server_config.options), ""},
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257 | {"opt", read_opt, &(server_config.options), ""},
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258 | {"max_leases", read_u32, &(server_config.max_leases), "254"},
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259 | {"remaining", read_yn, &(server_config.remaining), "yes"},
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260 | {"auto_time", read_u32, &(server_config.auto_time), "7200"},
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261 | {"decline_time",read_u32, &(server_config.decline_time),"3600"},
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262 | {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
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263 | {"offer_time", read_u32, &(server_config.offer_time), "60"},
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264 | {"min_lease", read_u32, &(server_config.min_lease), "60"},
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265 | {"lease_file", read_str, &(server_config.lease_file), LEASES_FILE},
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266 | {"pidfile", read_str, &(server_config.pidfile), "/var/run/udhcpd.pid"},
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267 | {"notify_file", read_str, &(server_config.notify_file), ""},
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268 | {"siaddr", read_ip, &(server_config.siaddr), "0.0.0.0"},
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269 | {"sname", read_str, &(server_config.sname), ""},
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270 | {"boot_file", read_str, &(server_config.boot_file), ""},
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271 | {"static_lease",read_staticlease, &(server_config.static_leases), ""},
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272 | /*ADDME: static lease */
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273 | {"", NULL, NULL, ""}
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274 | };
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275 |
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276 |
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277 | int read_config(const char *file)
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278 | {
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279 | FILE *in;
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280 | char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
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281 | int i, lm = 0;
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282 |
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283 | for (i = 0; keywords[i].keyword[0]; i++)
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284 | if (keywords[i].def[0])
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285 | keywords[i].handler(keywords[i].def, keywords[i].var);
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286 |
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287 | if (!(in = fopen(file, "r"))) {
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288 | LOG(LOG_ERR, "unable to open config file: %s", file);
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289 | return 0;
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290 | }
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291 |
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292 | while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
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293 | char debug_orig[READ_CONFIG_BUF_SIZE];
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294 |
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295 | lm++;
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296 | if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
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297 | if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
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298 | if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
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299 |
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300 | if (!(token = strtok(buffer, " \t"))) continue;
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301 | if (!(line = strtok(NULL, ""))) continue;
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302 |
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303 | /* eat leading whitespace */
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304 | line = line + strspn(line, " \t=");
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305 | /* eat trailing whitespace */
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306 | for (i = strlen(line); i > 0 && isspace(line[i - 1]); i--);
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307 | line[i] = '\0';
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308 |
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309 | for (i = 0; keywords[i].keyword[0]; i++)
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310 | if (!strcasecmp(token, keywords[i].keyword))
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311 | if (!keywords[i].handler(line, keywords[i].var)) {
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312 | LOG(LOG_ERR, "Failure parsing line %d of %s", lm, file);
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313 | DEBUG(LOG_ERR, "unable to parse '%s'", debug_orig);
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314 | /* reset back to the default value */
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315 | keywords[i].handler(keywords[i].def, keywords[i].var);
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316 | }
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317 | }
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318 | fclose(in);
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319 | return 1;
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320 | }
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321 |
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322 |
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323 | void write_leases(void)
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324 | {
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325 | FILE *fp;
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326 | unsigned int i;
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327 | char buf[255];
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328 | time_t curr = time(0);
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329 | unsigned long tmp_time;
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330 |
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331 | if (!(fp = fopen(server_config.lease_file, "w"))) {
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332 | LOG(LOG_ERR, "Unable to open %s for writing", server_config.lease_file);
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333 | return;
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334 | }
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335 |
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336 | for (i = 0; i < server_config.max_leases; i++) {
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337 | if (leases[i].yiaddr != 0) {
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338 |
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339 | /* screw with the time in the struct, for easier writing */
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340 | tmp_time = leases[i].expires;
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341 |
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342 | if (server_config.remaining) {
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343 | if (lease_expired(&(leases[i])))
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344 | leases[i].expires = 0;
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345 | else leases[i].expires -= curr;
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346 | } /* else stick with the time we got */
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347 | leases[i].expires = htonl(leases[i].expires);
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348 | fwrite(&leases[i], sizeof(struct dhcpOfferedAddr), 1, fp);
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349 |
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350 | /* Then restore it when done. */
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351 | leases[i].expires = tmp_time;
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352 | }
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353 | }
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354 | fclose(fp);
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355 |
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356 | if (server_config.notify_file) {
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357 | sprintf(buf, "%s %s", server_config.notify_file, server_config.lease_file);
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358 | system(buf);
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359 | }
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360 | }
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361 |
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362 |
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363 | void read_leases(const char *file)
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364 | {
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365 | FILE *fp;
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366 | unsigned int i = 0;
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367 | struct dhcpOfferedAddr lease;
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368 |
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369 | if (!(fp = fopen(file, "r"))) {
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370 | LOG(LOG_ERR, "Unable to open %s for reading", file);
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371 | return;
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372 | }
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373 |
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374 | while (i < server_config.max_leases && (fread(&lease, sizeof lease, 1, fp) == 1)) {
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375 | /* ADDME: is it a static lease */
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376 | if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
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377 | lease.expires = ntohl(lease.expires);
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378 | if (!server_config.remaining) lease.expires -= time(0);
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379 | if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
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380 | LOG(LOG_WARNING, "Too many leases while loading %s\n", file);
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381 | break;
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382 | }
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383 | i++;
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384 | }
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385 | }
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386 | DEBUG(LOG_INFO, "Read %d leases", i);
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387 | fclose(fp);
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388 | }
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