1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Mini ipcalc implementation for busybox
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4 | *
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5 | * By Jordan Crouse <jordan@cosmicpenguin.net>
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6 | * Stephan Linz <linz@li-pro.net>
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7 | *
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8 | * This is a complete reimplementation of the ipcalc program
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9 | * from Red Hat. I didn't look at their source code, but there
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10 | * is no denying that this is a loving reimplementation
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11 | *
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12 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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13 | */
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14 |
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15 | //usage:#define ipcalc_trivial_usage
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16 | //usage: "[OPTIONS] ADDRESS[[/]NETMASK] [NETMASK]"
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17 | //usage:#define ipcalc_full_usage "\n\n"
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18 | //usage: "Calculate IP network settings from a IP address\n"
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19 | //usage: IF_FEATURE_IPCALC_LONG_OPTIONS(
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20 | //usage: "\n -b,--broadcast Display calculated broadcast address"
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21 | //usage: "\n -n,--network Display calculated network address"
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22 | //usage: "\n -m,--netmask Display default netmask for IP"
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23 | //usage: IF_FEATURE_IPCALC_FANCY(
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24 | //usage: "\n -p,--prefix Display the prefix for IP/NETMASK"
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25 | //usage: "\n -h,--hostname Display first resolved host name"
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26 | //usage: "\n -s,--silent Don't ever display error messages"
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27 | //usage: )
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28 | //usage: )
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29 | //usage: IF_NOT_FEATURE_IPCALC_LONG_OPTIONS(
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30 | //usage: "\n -b Display calculated broadcast address"
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31 | //usage: "\n -n Display calculated network address"
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32 | //usage: "\n -m Display default netmask for IP"
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33 | //usage: IF_FEATURE_IPCALC_FANCY(
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34 | //usage: "\n -p Display the prefix for IP/NETMASK"
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35 | //usage: "\n -h Display first resolved host name"
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36 | //usage: "\n -s Don't ever display error messages"
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37 | //usage: )
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38 | //usage: )
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39 |
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40 | #include "libbb.h"
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41 | /* After libbb.h, because on some systems it needs other includes */
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42 | #include <arpa/inet.h>
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43 |
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44 | #define CLASS_A_NETMASK ntohl(0xFF000000)
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45 | #define CLASS_B_NETMASK ntohl(0xFFFF0000)
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46 | #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
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47 |
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48 | static unsigned long get_netmask(unsigned long ipaddr)
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49 | {
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50 | ipaddr = htonl(ipaddr);
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51 |
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52 | if ((ipaddr & 0xC0000000) == 0xC0000000)
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53 | return CLASS_C_NETMASK;
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54 | else if ((ipaddr & 0x80000000) == 0x80000000)
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55 | return CLASS_B_NETMASK;
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56 | else if ((ipaddr & 0x80000000) == 0)
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57 | return CLASS_A_NETMASK;
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58 | else
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59 | return 0;
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60 | }
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61 |
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62 | #if ENABLE_FEATURE_IPCALC_FANCY
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63 | static int get_prefix(unsigned long netmask)
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64 | {
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65 | unsigned long msk = 0x80000000;
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66 | int ret = 0;
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67 |
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68 | netmask = htonl(netmask);
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69 | while (msk) {
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70 | if (netmask & msk)
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71 | ret++;
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72 | msk >>= 1;
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73 | }
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74 | return ret;
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75 | }
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76 | #else
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77 | int get_prefix(unsigned long netmask);
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78 | #endif
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79 |
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80 |
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81 | #define NETMASK 0x01
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82 | #define BROADCAST 0x02
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83 | #define NETWORK 0x04
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84 | #define NETPREFIX 0x08
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85 | #define HOSTNAME 0x10
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86 | #define SILENT 0x20
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87 |
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88 | #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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89 | static const char ipcalc_longopts[] ALIGN1 =
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90 | "netmask\0" No_argument "m" // netmask from IP (assuming complete class A, B, or C network)
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91 | "broadcast\0" No_argument "b" // broadcast from IP [netmask]
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92 | "network\0" No_argument "n" // network from IP [netmask]
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93 | # if ENABLE_FEATURE_IPCALC_FANCY
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94 | "prefix\0" No_argument "p" // prefix from IP[/prefix] [netmask]
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95 | "hostname\0" No_argument "h" // hostname from IP
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96 | "silent\0" No_argument "s" // don’t ever display error messages
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97 | # endif
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98 | ;
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99 | #endif
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100 |
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101 | int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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102 | int ipcalc_main(int argc UNUSED_PARAM, char **argv)
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103 | {
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104 | unsigned opt;
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105 | bool have_netmask = 0;
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106 | struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
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107 | /* struct in_addr { in_addr_t s_addr; } and in_addr_t
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108 | * (which in turn is just a typedef to uint32_t)
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109 | * are essentially the same type. A few macros for less verbosity: */
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110 | #define netmask (s_netmask.s_addr)
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111 | #define broadcast (s_broadcast.s_addr)
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112 | #define network (s_network.s_addr)
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113 | #define ipaddr (s_ipaddr.s_addr)
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114 | char *ipstr;
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115 |
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116 | #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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117 | applet_long_options = ipcalc_longopts;
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118 | #endif
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119 | opt_complementary = "-1:?2"; /* minimum 1 arg, maximum 2 args */
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120 | opt = getopt32(argv, "mbn" IF_FEATURE_IPCALC_FANCY("phs"));
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121 | argv += optind;
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122 | if (opt & SILENT)
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123 | logmode = LOGMODE_NONE; /* suppress error_msg() output */
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124 | opt &= ~SILENT;
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125 | if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) {
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126 | /* if no options at all or
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127 | * (no broadcast,network,prefix) and (two args)... */
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128 | if (!opt || argv[1])
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129 | bb_show_usage();
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130 | }
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131 |
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132 | ipstr = argv[0];
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133 | if (ENABLE_FEATURE_IPCALC_FANCY) {
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134 | unsigned long netprefix = 0;
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135 | char *prefixstr;
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136 |
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137 | prefixstr = ipstr;
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138 |
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139 | while (*prefixstr) {
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140 | if (*prefixstr == '/') {
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141 | *prefixstr++ = '\0';
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142 | if (*prefixstr) {
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143 | unsigned msk;
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144 | netprefix = xatoul_range(prefixstr, 0, 32);
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145 | netmask = 0;
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146 | msk = 0x80000000;
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147 | while (netprefix > 0) {
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148 | netmask |= msk;
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149 | msk >>= 1;
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150 | netprefix--;
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151 | }
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152 | netmask = htonl(netmask);
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153 | /* Even if it was 0, we will signify that we have a netmask. This allows */
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154 | /* for specification of default routes, etc which have a 0 netmask/prefix */
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155 | have_netmask = 1;
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156 | }
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157 | break;
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158 | }
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159 | prefixstr++;
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160 | }
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161 | }
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162 |
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163 | if (inet_aton(ipstr, &s_ipaddr) == 0) {
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164 | bb_error_msg_and_die("bad IP address: %s", argv[0]);
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165 | }
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166 |
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167 | if (argv[1]) {
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168 | if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
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169 | bb_error_msg_and_die("use prefix or netmask, not both");
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170 | }
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171 | if (inet_aton(argv[1], &s_netmask) == 0) {
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172 | bb_error_msg_and_die("bad netmask: %s", argv[1]);
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173 | }
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174 | } else {
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175 | /* JHC - If the netmask wasn't provided then calculate it */
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176 | if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
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177 | netmask = get_netmask(ipaddr);
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178 | }
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179 |
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180 | if (opt & NETMASK) {
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181 | printf("NETMASK=%s\n", inet_ntoa(s_netmask));
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182 | }
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183 |
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184 | if (opt & BROADCAST) {
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185 | broadcast = (ipaddr & netmask) | ~netmask;
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186 | printf("BROADCAST=%s\n", inet_ntoa(s_broadcast));
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187 | }
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188 |
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189 | if (opt & NETWORK) {
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190 | network = ipaddr & netmask;
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191 | printf("NETWORK=%s\n", inet_ntoa(s_network));
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192 | }
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193 |
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194 | if (ENABLE_FEATURE_IPCALC_FANCY) {
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195 | if (opt & NETPREFIX) {
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196 | printf("PREFIX=%i\n", get_prefix(netmask));
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197 | }
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198 |
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199 | if (opt & HOSTNAME) {
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200 | struct hostent *hostinfo;
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201 |
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202 | hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
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203 | if (!hostinfo) {
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204 | bb_herror_msg_and_die("can't find hostname for %s", argv[0]);
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205 | }
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206 | str_tolower(hostinfo->h_name);
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207 |
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208 | printf("HOSTNAME=%s\n", hostinfo->h_name);
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209 | }
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210 | }
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211 |
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212 | return EXIT_SUCCESS;
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213 | }
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