1 | /* vi: set sw=4 ts=4 ai: */
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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 tarball for details.
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13 | */
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14 |
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15 | #include "busybox.h"
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16 | #include <ctype.h>
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17 | #include <getopt.h>
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18 | #include <sys/socket.h>
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19 | #include <arpa/inet.h>
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20 |
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21 | #define IPCALC_MSG(CMD,ALTCMD) if (mode & SILENT) {ALTCMD;} else {CMD;}
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22 |
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23 | #define CLASS_A_NETMASK ntohl(0xFF000000)
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24 | #define CLASS_B_NETMASK ntohl(0xFFFF0000)
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25 | #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
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26 |
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27 | static unsigned long get_netmask(unsigned long ipaddr)
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28 | {
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29 | ipaddr = htonl(ipaddr);
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30 |
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31 | if ((ipaddr & 0xC0000000) == 0xC0000000)
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32 | return CLASS_C_NETMASK;
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33 | else if ((ipaddr & 0x80000000) == 0x80000000)
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34 | return CLASS_B_NETMASK;
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35 | else if ((ipaddr & 0x80000000) == 0)
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36 | return CLASS_A_NETMASK;
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37 | else
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38 | return 0;
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39 | }
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40 |
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41 | #ifdef CONFIG_FEATURE_IPCALC_FANCY
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42 | static int get_prefix(unsigned long netmask)
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43 | {
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44 | unsigned long msk = 0x80000000;
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45 | int ret = 0;
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46 |
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47 | netmask = htonl(netmask);
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48 | while(msk) {
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49 | if (netmask & msk)
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50 | ret++;
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51 | msk >>= 1;
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52 | }
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53 | return ret;
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54 | }
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55 | #else
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56 | int get_prefix(unsigned long netmask);
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57 | #endif
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58 |
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59 | #define NETMASK 0x01
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60 | #define BROADCAST 0x02
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61 | #define NETWORK 0x04
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62 | #define NETPREFIX 0x08
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63 | #define HOSTNAME 0x10
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64 | #define SILENT 0x20
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65 |
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66 | #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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67 | static const struct option long_options[] = {
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68 | {"netmask", no_argument, NULL, 'm'},
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69 | {"broadcast", no_argument, NULL, 'b'},
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70 | {"network", no_argument, NULL, 'n'},
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71 | #ifdef CONFIG_FEATURE_IPCALC_FANCY
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72 | {"prefix", no_argument, NULL, 'p'},
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73 | {"hostname", no_argument, NULL, 'h'},
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74 | {"silent", no_argument, NULL, 's'},
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75 | #endif
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76 | {NULL, 0, NULL, 0}
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77 | };
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78 | #else
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79 | #define long_options 0
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80 | #endif
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81 |
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82 |
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83 |
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84 | int ipcalc_main(int argc, char **argv)
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85 | {
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86 | unsigned long mode;
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87 | int have_netmask = 0;
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88 | in_addr_t netmask, broadcast, network, ipaddr;
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89 | struct in_addr a;
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90 | char *ipstr;
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91 |
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92 | if (ENABLE_FEATURE_IPCALC_LONG_OPTIONS)
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93 | bb_applet_long_options = long_options;
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94 |
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95 | mode = bb_getopt_ulflags(argc, argv, "mbn" USE_FEATURE_IPCALC_FANCY("phs"));
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96 |
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97 | argc -= optind;
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98 | argv += optind;
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99 | if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
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100 | if (argc > 2 || argc <= 0)
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101 | bb_show_usage();
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102 | } else {
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103 | if (argc != 1)
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104 | bb_show_usage();
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105 | }
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106 |
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107 | ipstr = argv[0];
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108 | if (ENABLE_FEATURE_IPCALC_FANCY) {
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109 | unsigned long netprefix = 0;
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110 | char *prefixstr;
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111 |
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112 | prefixstr = ipstr;
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113 |
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114 | while(*prefixstr) {
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115 | if (*prefixstr == '/') {
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116 | *prefixstr = (char)0;
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117 | prefixstr++;
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118 | if (*prefixstr) {
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119 | unsigned int msk;
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120 |
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121 | if (safe_strtoul(prefixstr, &netprefix) || netprefix > 32) {
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122 | IPCALC_MSG(bb_error_msg_and_die("bad IP prefix: %s\n", prefixstr),
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123 | exit(EXIT_FAILURE));
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124 | }
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125 | netmask = 0;
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126 | msk = 0x80000000;
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127 | while (netprefix > 0) {
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128 | netmask |= msk;
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129 | msk >>= 1;
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130 | netprefix--;
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131 | }
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132 | netmask = htonl(netmask);
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133 | /* Even if it was 0, we will signify that we have a netmask. This allows */
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134 | /* for specification of default routes, etc which have a 0 netmask/prefix */
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135 | have_netmask = 1;
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136 | }
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137 | break;
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138 | }
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139 | prefixstr++;
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140 | }
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141 | }
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142 | ipaddr = inet_aton(ipstr, &a);
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143 |
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144 | if (ipaddr == 0) {
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145 | IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[0]),
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146 | exit(EXIT_FAILURE));
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147 | }
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148 | ipaddr = a.s_addr;
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149 |
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150 | if (argc == 2) {
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151 | if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
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152 | IPCALC_MSG(bb_error_msg_and_die("Use prefix or netmask, not both.\n"),
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153 | exit(EXIT_FAILURE));
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154 | }
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155 |
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156 | netmask = inet_aton(argv[1], &a);
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157 | if (netmask == 0) {
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158 | IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[1]),
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159 | exit(EXIT_FAILURE));
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160 | }
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161 | netmask = a.s_addr;
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162 | } else {
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163 |
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164 | /* JHC - If the netmask wasn't provided then calculate it */
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165 | if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
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166 | netmask = get_netmask(ipaddr);
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167 | }
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168 |
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169 | if (mode & NETMASK) {
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170 | printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
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171 | }
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172 |
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173 | if (mode & BROADCAST) {
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174 | broadcast = (ipaddr & netmask) | ~netmask;
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175 | printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
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176 | }
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177 |
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178 | if (mode & NETWORK) {
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179 | network = ipaddr & netmask;
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180 | printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
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181 | }
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182 |
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183 | if (ENABLE_FEATURE_IPCALC_FANCY) {
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184 | if (mode & NETPREFIX) {
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185 | printf("PREFIX=%i\n", get_prefix(netmask));
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186 | }
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187 |
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188 | if (mode & HOSTNAME) {
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189 | struct hostent *hostinfo;
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190 | int x;
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191 |
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192 | hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
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193 | if (!hostinfo) {
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194 | IPCALC_MSG(bb_herror_msg_and_die(
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195 | "cannot find hostname for %s", argv[0]),);
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196 | exit(EXIT_FAILURE);
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197 | }
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198 | for (x = 0; hostinfo->h_name[x]; x++) {
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199 | hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
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200 | }
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201 |
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202 | printf("HOSTNAME=%s\n", hostinfo->h_name);
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203 | }
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204 | }
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205 |
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206 | return EXIT_SUCCESS;
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207 | }
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