networking/ipcalc.c

   1 /* vi: set sw=4 ts=4 ai: */
   2 /*
   3  * Mini ipcalc implementation for busybox
   4  *
   5  * By Jordan Crouse <jordan@cosmicpenguin.net>
   6  *    Stephan Linz  <linz@li-pro.net>
   7  *
   8  * This is a complete reimplentation of the ipcalc program
   9  * from Redhat.  I didn't look at their source code, but there
  10  * is no denying that this is a loving reimplementation
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <ctype.h>
  16 #include <getopt.h>
  17 #include <sys/socket.h>
  18 #include <netinet/in.h>
  19 #include <arpa/inet.h>
  20
  21 #include "busybox.h"
  22
  23 #define IPCALC_MSG(CMD,ALTCMD) if (mode & SILENT) {ALTCMD;} else {CMD;}
  24
  25 #define CLASS_A_NETMASK ntohl(0xFF000000)
  26 #define CLASS_B_NETMASK ntohl(0xFFFF0000)
  27 #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
  28
  29 static unsigned long get_netmask(unsigned long ipaddr)
  30 {
  31         ipaddr = htonl(ipaddr);
  32
  33         if ((ipaddr & 0xC0000000) == 0xC0000000)
  34                 return CLASS_C_NETMASK;
  35         else if ((ipaddr & 0x80000000) == 0x80000000)
  36                 return CLASS_B_NETMASK;
  37         else if ((ipaddr & 0x80000000) == 0)
  38                 return CLASS_A_NETMASK;
  39         else
  40                 return 0;
  41 }
  42
  43 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  44 static int get_prefix(unsigned long netmask)
  45 {
  46         unsigned long t;
  47         int ret = 0;
  48
  49         for (t = 0; t < 32; t++) {
  50                 if (htonl(netmask) & (0x80000000 >> t)) {
  51                         ret ++;
  52                 } else {
  53                         break;
  54                 }
  55         }
  56         return ret;
  57 }
  58 #endif
  59
  60 #define NETMASK   0x01
  61 #define BROADCAST 0x02
  62 #define NETWORK   0x04
  63 #define NETPREFIX 0x08
  64 #define HOSTNAME  0x10
  65 #define SILENT    0x20
  66
  67 int ipcalc_main(int argc, char **argv)
  68 {
  69         unsigned long mode;
  70
  71         unsigned long netmask = 0;
  72         unsigned long broadcast;
  73         unsigned long network;
  74         unsigned long ipaddr;
  75
  76 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  77         unsigned long netprefix = 0;
  78         int have_netmask = 0;
  79         char *ipstr, *prefixstr;
  80 #endif
  81
  82         static const struct option long_options[] = {
  83                 {"netmask", no_argument, NULL, 'm'},
  84                 {"broadcast", no_argument, NULL, 'b'},
  85                 {"network", no_argument, NULL, 'n'},
  86 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  87                 {"prefix", no_argument, NULL, 'p'},
  88                 {"hostname", no_argument, NULL, 'h'},
  89                 {"silent", no_argument, NULL, 's'},
  90 #endif
  91                 {NULL, 0, NULL, 0}
  92         };
  93
  94         bb_applet_long_options = long_options;
  95         mode = bb_getopt_ulflags(argc, argv,
  96 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  97                                                           "mbnphs");
  98 #else
  99                                                           "mbn");
 100 #endif
 101         if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
 102                 if (argc - optind > 2) {
 103                         bb_show_usage();
 104                 }
 105         } else {
 106                 if (argc - optind != 1) {
 107                         bb_show_usage();
 108                 }
 109         }
 110
 111 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 112         prefixstr = ipstr = argv[optind];
 113
 114         while(*prefixstr) {
 115                 if (*prefixstr == '/') {
 116                         *prefixstr = (char)0;
 117                         prefixstr++;
 118                         if (*prefixstr) {
 119                                 netprefix = atol(prefixstr);
 120                                 if (netprefix > 32) {
 121                                         IPCALC_MSG(bb_error_msg_and_die("bad IP prefix: %s\n", prefixstr),
 122                                                 exit(EXIT_FAILURE));
 123                                 }
 124                                 if (netprefix) {
 125                                         netmask = 0x80000000;
 126                                         netprefix--;
 127                                         while(netprefix) {
 128                                                 netmask = 0x80000000 | (netmask >> 1);
 129                                                 netprefix--;
 130                                         }
 131                                         netmask = htonl(netmask);
 132                                 }
 133                                 /* Even if it was 0, we will signify that we have a netmask. This allows */
 134                                 /* for specification of default routes, etc which have a 0 netmask/prefix */
 135                                 have_netmask = 1;
 136                         }
 137                         break;
 138                 }
 139                 prefixstr++;
 140         }
 141         ipaddr = inet_addr(ipstr);
 142 #else
 143         ipaddr = inet_addr(argv[optind]);
 144 #endif
 145
 146         if (ipaddr == INADDR_NONE) {
 147                 IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[optind]),
 148                                    exit(EXIT_FAILURE));
 149         }
 150
 151         if (argc - optind == 2) {
 152 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 153                if (have_netmask == 1) {
 154                         IPCALC_MSG(bb_error_msg_and_die("Both prefix and netmask were specified, use one or the other.\n"),
 155                                 exit(EXIT_FAILURE));
 156                 }
 157                 have_netmask = 1;
 158 #endif
 159                 netmask = inet_addr(argv[optind + 1]);
 160         }
 161
 162         if (ipaddr == INADDR_NONE) {
 163                 IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[optind + 1]),
 164                                    exit(EXIT_FAILURE));
 165         }
 166
 167         /* JHC - If the netmask wasn't provided then calculate it */
 168         if (!netmask) {
 169                 netmask = get_netmask(ipaddr);
 170         }
 171
 172         if (mode & NETMASK) {
 173                 printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
 174         }
 175
 176         if (mode & BROADCAST) {
 177                 broadcast = (ipaddr & netmask) | ~netmask;
 178                 printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
 179         }
 180
 181         if (mode & NETWORK) {
 182                 network = ipaddr & netmask;
 183                 printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
 184         }
 185
 186 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 187         if (mode & NETPREFIX) {
 188                 printf("PREFIX=%i\n", get_prefix(netmask));
 189         }
 190
 191         if (mode & HOSTNAME) {
 192                 struct hostent *hostinfo;
 193                 int x;
 194
 195                 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
 196                 if (!hostinfo) {
 197                         IPCALC_MSG(bb_herror_msg_and_die(
 198                                 "cannot find hostname for %s", argv[optind]),);
 199                         exit(EXIT_FAILURE);
 200                 }
 201                 for (x = 0; hostinfo->h_name[x]; x++) {
 202                         hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
 203                 }
 204
 205                 printf("HOSTNAME=%s\n", hostinfo->h_name);
 206         }
 207 #endif
 208
 209         return EXIT_SUCCESS;
 210 }
 211
 212 /* END CODE */
 213 /*
 214 Local Variables:
 215 c-file-style: "linux"
 216 c-basic-offset: 4
 217 tab-width: 4
 218 End:
 219 */