1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * files.c -- DHCP server file manipulation *
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4 | * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
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5 | */
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6 |
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7 | #include <netinet/ether.h>
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8 |
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9 | #include "common.h"
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10 | #include "dhcpd.h"
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11 | #include "options.h"
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12 |
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13 |
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14 | /* on these functions, make sure your datatype matches */
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15 | static int read_ip(const char *line, void *arg)
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16 | {
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17 | len_and_sockaddr *lsa;
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18 |
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19 | lsa = host_and_af2sockaddr(line, 0, AF_INET);
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20 | if (!lsa)
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21 | return 0;
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22 | *(uint32_t*)arg = lsa->sin.sin_addr.s_addr;
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23 | free(lsa);
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24 | return 1;
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25 | }
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26 |
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27 | static int read_mac(const char *line, void *arg)
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28 | {
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29 | uint8_t *mac_bytes = arg;
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30 | struct ether_addr *temp_ether_addr;
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31 |
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32 | temp_ether_addr = ether_aton(line);
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33 | if (temp_ether_addr == NULL)
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34 | return 0;
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35 | memcpy(mac_bytes, temp_ether_addr, 6);
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36 | return 1;
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37 | }
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38 |
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39 |
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40 | static int read_str(const char *line, void *arg)
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41 | {
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42 | char **dest = arg;
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43 |
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44 | free(*dest);
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45 | *dest = xstrdup(line);
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46 | return 1;
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47 | }
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48 |
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49 |
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50 | static int read_u32(const char *line, void *arg)
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51 | {
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52 | *(uint32_t*)arg = bb_strtou32(line, NULL, 10);
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53 | return errno == 0;
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54 | }
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55 |
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56 |
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57 | static int read_yn(const char *line, void *arg)
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58 | {
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59 | char *dest = arg;
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60 |
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61 | if (!strcasecmp("yes", line)) {
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62 | *dest = 1;
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63 | return 1;
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64 | }
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65 | if (!strcasecmp("no", line)) {
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66 | *dest = 0;
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67 | return 1;
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68 | }
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69 | return 0;
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70 | }
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71 |
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72 |
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73 | /* find option 'code' in opt_list */
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74 | struct option_set *find_option(struct option_set *opt_list, char code)
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75 | {
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76 | while (opt_list && opt_list->data[OPT_CODE] < code)
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77 | opt_list = opt_list->next;
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78 |
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79 | if (opt_list && opt_list->data[OPT_CODE] == code)
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80 | return opt_list;
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81 | return NULL;
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82 | }
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83 |
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84 |
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85 | /* add an option to the opt_list */
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86 | static void attach_option(struct option_set **opt_list,
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87 | const struct dhcp_option *option, char *buffer, int length)
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88 | {
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89 | struct option_set *existing, *new, **curr;
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90 |
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91 | existing = find_option(*opt_list, option->code);
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92 | if (!existing) {
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93 | DEBUG("Attaching option %s to list", option->name);
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94 |
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95 | #if ENABLE_FEATURE_RFC3397
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96 | if ((option->flags & TYPE_MASK) == OPTION_STR1035)
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97 | /* reuse buffer and length for RFC1035-formatted string */
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98 | buffer = dname_enc(NULL, 0, buffer, &length);
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99 | #endif
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100 |
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101 | /* make a new option */
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102 | new = xmalloc(sizeof(*new));
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103 | new->data = xmalloc(length + 2);
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104 | new->data[OPT_CODE] = option->code;
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105 | new->data[OPT_LEN] = length;
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106 | memcpy(new->data + 2, buffer, length);
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107 |
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108 | curr = opt_list;
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109 | while (*curr && (*curr)->data[OPT_CODE] < option->code)
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110 | curr = &(*curr)->next;
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111 |
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112 | new->next = *curr;
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113 | *curr = new;
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114 | #if ENABLE_FEATURE_RFC3397
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115 | if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
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116 | free(buffer);
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117 | #endif
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118 | return;
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119 | }
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120 |
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121 | /* add it to an existing option */
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122 | DEBUG("Attaching option %s to existing member of list", option->name);
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123 | if (option->flags & OPTION_LIST) {
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124 | #if ENABLE_FEATURE_RFC3397
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125 | if ((option->flags & TYPE_MASK) == OPTION_STR1035)
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126 | /* reuse buffer and length for RFC1035-formatted string */
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127 | buffer = dname_enc(existing->data + 2,
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128 | existing->data[OPT_LEN], buffer, &length);
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129 | #endif
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130 | if (existing->data[OPT_LEN] + length <= 255) {
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131 | existing->data = xrealloc(existing->data,
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132 | existing->data[OPT_LEN] + length + 3);
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133 | if ((option->flags & TYPE_MASK) == OPTION_STRING) {
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134 | /* ' ' can bring us to 256 - bad */
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135 | if (existing->data[OPT_LEN] + length >= 255)
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136 | return;
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137 | /* add space separator between STRING options in a list */
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138 | existing->data[existing->data[OPT_LEN] + 2] = ' ';
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139 | existing->data[OPT_LEN]++;
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140 | }
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141 | memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
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142 | existing->data[OPT_LEN] += length;
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143 | } /* else, ignore the data, we could put this in a second option in the future */
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144 | #if ENABLE_FEATURE_RFC3397
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145 | if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
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146 | free(buffer);
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147 | #endif
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148 | } /* else, ignore the new data */
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149 | }
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150 |
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151 |
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152 | /* read a dhcp option and add it to opt_list */
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153 | static int read_opt(const char *const_line, void *arg)
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154 | {
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155 | struct option_set **opt_list = arg;
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156 | char *opt, *val, *endptr;
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157 | const struct dhcp_option *option;
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158 | int retval = 0, length;
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159 | char buffer[8];
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160 | char *line;
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161 | uint16_t *result_u16 = (uint16_t *) buffer;
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162 | uint32_t *result_u32 = (uint32_t *) buffer;
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163 |
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164 | /* Cheat, the only const line we'll actually get is "" */
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165 | line = (char *) const_line;
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166 | opt = strtok(line, " \t=");
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167 | if (!opt) return 0;
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168 |
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169 | option = dhcp_options;
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170 | while (1) {
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171 | if (!option->code)
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172 | return 0;
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173 | if (!strcasecmp(option->name, opt))
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174 | break;
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175 | option++;
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176 | }
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177 |
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178 | do {
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179 | val = strtok(NULL, ", \t");
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180 | if (!val) break;
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181 | length = option_lengths[option->flags & TYPE_MASK];
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182 | retval = 0;
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183 | opt = buffer; /* new meaning for variable opt */
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184 | switch (option->flags & TYPE_MASK) {
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185 | case OPTION_IP:
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186 | retval = read_ip(val, buffer);
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187 | break;
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188 | case OPTION_IP_PAIR:
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189 | retval = read_ip(val, buffer);
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190 | val = strtok(NULL, ", \t/-");
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191 | if (!val)
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192 | retval = 0;
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193 | if (retval)
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194 | retval = read_ip(val, buffer + 4);
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195 | break;
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196 | case OPTION_STRING:
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197 | #if ENABLE_FEATURE_RFC3397
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198 | case OPTION_STR1035:
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199 | #endif
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200 | length = strlen(val);
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201 | if (length > 0) {
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202 | if (length > 254) length = 254;
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203 | opt = val;
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204 | retval = 1;
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205 | }
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206 | break;
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207 | case OPTION_BOOLEAN:
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208 | retval = read_yn(val, buffer);
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209 | break;
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210 | case OPTION_U8:
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211 | buffer[0] = strtoul(val, &endptr, 0);
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212 | retval = (endptr[0] == '\0');
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213 | break;
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214 | /* htonX are macros in older libc's, using temp var
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215 | * in code below for safety */
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216 | /* TODO: use bb_strtoX? */
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217 | case OPTION_U16: {
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218 | unsigned long tmp = strtoul(val, &endptr, 0);
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219 | *result_u16 = htons(tmp);
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220 | retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
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221 | break;
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222 | }
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223 | case OPTION_S16: {
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224 | long tmp = strtol(val, &endptr, 0);
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225 | *result_u16 = htons(tmp);
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226 | retval = (endptr[0] == '\0');
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227 | break;
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228 | }
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229 | case OPTION_U32: {
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230 | unsigned long tmp = strtoul(val, &endptr, 0);
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231 | *result_u32 = htonl(tmp);
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232 | retval = (endptr[0] == '\0');
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233 | break;
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234 | }
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235 | case OPTION_S32: {
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236 | long tmp = strtol(val, &endptr, 0);
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237 | *result_u32 = htonl(tmp);
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238 | retval = (endptr[0] == '\0');
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239 | break;
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240 | }
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241 | default:
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242 | break;
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243 | }
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244 | if (retval)
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245 | attach_option(opt_list, option, opt, length);
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246 | } while (retval && option->flags & OPTION_LIST);
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247 | return retval;
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248 | }
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249 |
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250 | static int read_staticlease(const char *const_line, void *arg)
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251 | {
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252 | char *line;
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253 | char *mac_string;
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254 | char *ip_string;
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255 | uint8_t *mac_bytes;
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256 | uint32_t *ip;
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257 |
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258 | /* Allocate memory for addresses */
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259 | mac_bytes = xmalloc(sizeof(unsigned char) * 8);
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260 | ip = xmalloc(sizeof(uint32_t));
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261 |
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262 | /* Read mac */
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263 | line = (char *) const_line;
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264 | mac_string = strtok(line, " \t");
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265 | read_mac(mac_string, mac_bytes);
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266 |
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267 | /* Read ip */
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268 | ip_string = strtok(NULL, " \t");
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269 | read_ip(ip_string, ip);
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270 |
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271 | addStaticLease(arg, mac_bytes, ip);
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272 |
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273 | if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
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274 |
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275 | return 1;
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276 | }
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277 |
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278 |
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279 | struct config_keyword {
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280 | const char *keyword;
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281 | int (*handler)(const char *line, void *var);
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282 | void *var;
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283 | const char *def;
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284 | };
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285 |
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286 | static const struct config_keyword keywords[] = {
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287 | /* keyword handler variable address default */
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288 | {"start", read_ip, &(server_config.start_ip), "192.168.0.20"},
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289 | {"end", read_ip, &(server_config.end_ip), "192.168.0.254"},
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290 | {"interface", read_str, &(server_config.interface), "eth0"},
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291 | {"option", read_opt, &(server_config.options), ""},
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292 | {"opt", read_opt, &(server_config.options), ""},
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293 | /* Avoid "max_leases value not sane" warning by setting default
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294 | * to default_end_ip - default_start_ip + 1: */
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295 | {"max_leases", read_u32, &(server_config.max_leases), "235"},
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296 | {"remaining", read_yn, &(server_config.remaining), "yes"},
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297 | {"auto_time", read_u32, &(server_config.auto_time), "7200"},
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298 | {"decline_time", read_u32, &(server_config.decline_time), "3600"},
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299 | {"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
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300 | {"offer_time", read_u32, &(server_config.offer_time), "60"},
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301 | {"min_lease", read_u32, &(server_config.min_lease), "60"},
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302 | {"lease_file", read_str, &(server_config.lease_file), LEASES_FILE},
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303 | {"pidfile", read_str, &(server_config.pidfile), "/var/run/udhcpd.pid"},
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304 | {"notify_file", read_str, &(server_config.notify_file), ""},
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305 | {"siaddr", read_ip, &(server_config.siaddr), "0.0.0.0"},
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306 | {"sname", read_str, &(server_config.sname), ""},
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307 | {"boot_file", read_str, &(server_config.boot_file), ""},
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308 | {"static_lease", read_staticlease, &(server_config.static_leases), ""},
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309 | /* ADDME: static lease */
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310 | };
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311 |
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312 |
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313 | /*
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314 | * Domain names may have 254 chars, and string options can be 254
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315 | * chars long. However, 80 bytes will be enough for most, and won't
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316 | * hog up memory. If you have a special application, change it
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317 | */
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318 | #define READ_CONFIG_BUF_SIZE 80
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319 |
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320 | int read_config(const char *file)
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321 | {
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322 | FILE *in;
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323 | char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
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324 | int i, lm = 0;
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325 |
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326 | for (i = 0; i < ARRAY_SIZE(keywords); i++)
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327 | if (keywords[i].def[0])
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328 | keywords[i].handler(keywords[i].def, keywords[i].var);
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329 |
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330 | in = fopen_or_warn(file, "r");
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331 | if (!in) {
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332 | return 0;
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333 | }
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334 |
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335 | while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
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336 | char debug_orig[READ_CONFIG_BUF_SIZE];
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337 | char *p;
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338 |
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339 | lm++;
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340 | p = strchr(buffer, '\n');
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341 | if (p) *p = '\0';
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342 | if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
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343 | p = strchr(buffer, '#');
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344 | if (p) *p = '\0';
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345 |
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346 | if (!(token = strtok(buffer, " \t"))) continue;
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347 | if (!(line = strtok(NULL, ""))) continue;
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348 |
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349 | /* eat leading whitespace */
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350 | line = skip_whitespace(line);
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351 | /* eat trailing whitespace */
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352 | i = strlen(line) - 1;
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353 | while (i >= 0 && isspace(line[i]))
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354 | line[i--] = '\0';
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355 |
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356 | for (i = 0; i < ARRAY_SIZE(keywords); i++)
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357 | if (!strcasecmp(token, keywords[i].keyword))
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358 | if (!keywords[i].handler(line, keywords[i].var)) {
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359 | bb_error_msg("cannot parse line %d of %s", lm, file);
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360 | if (ENABLE_FEATURE_UDHCP_DEBUG)
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361 | bb_error_msg("cannot parse '%s'", debug_orig);
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362 | /* reset back to the default value */
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363 | keywords[i].handler(keywords[i].def, keywords[i].var);
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364 | }
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365 | }
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366 | fclose(in);
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367 |
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368 | server_config.start_ip = ntohl(server_config.start_ip);
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369 | server_config.end_ip = ntohl(server_config.end_ip);
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370 |
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371 | return 1;
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372 | }
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373 |
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374 |
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375 | void write_leases(void)
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376 | {
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377 | int fp;
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378 | unsigned i;
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379 | time_t curr = time(0);
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380 | unsigned long tmp_time;
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381 |
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382 | fp = open3_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC, 0666);
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383 | if (fp < 0) {
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384 | return;
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385 | }
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386 |
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387 | for (i = 0; i < server_config.max_leases; i++) {
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388 | if (leases[i].yiaddr != 0) {
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389 |
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390 | /* screw with the time in the struct, for easier writing */
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391 | tmp_time = leases[i].expires;
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392 |
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393 | if (server_config.remaining) {
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394 | if (lease_expired(&(leases[i])))
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395 | leases[i].expires = 0;
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396 | else leases[i].expires -= curr;
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397 | } /* else stick with the time we got */
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398 | leases[i].expires = htonl(leases[i].expires);
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399 | // FIXME: error check??
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400 | full_write(fp, &leases[i], sizeof(leases[i]));
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401 |
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402 | /* then restore it when done */
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403 | leases[i].expires = tmp_time;
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404 | }
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405 | }
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406 | close(fp);
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407 |
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408 | if (server_config.notify_file) {
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409 | char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
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410 | system(cmd);
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411 | free(cmd);
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412 | }
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413 | }
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414 |
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415 |
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416 | void read_leases(const char *file)
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417 | {
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418 | int fp;
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419 | unsigned int i = 0;
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420 | struct dhcpOfferedAddr lease;
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421 |
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422 | fp = open_or_warn(file, O_RDONLY);
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423 | if (fp < 0) {
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424 | return;
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425 | }
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426 |
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427 | while (i < server_config.max_leases
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428 | && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
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429 | ) {
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430 | /* ADDME: is it a static lease */
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431 | uint32_t y = ntohl(lease.yiaddr);
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432 | if (y >= server_config.start_ip && y <= server_config.end_ip) {
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433 | lease.expires = ntohl(lease.expires);
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434 | if (!server_config.remaining)
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435 | lease.expires -= time(0);
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436 | if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
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437 | bb_error_msg("too many leases while loading %s", file);
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438 | break;
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439 | }
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440 | i++;
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441 | }
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442 | }
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443 | DEBUG("Read %d leases", i);
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444 | close(fp);
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445 | }
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