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 msk = 0x80000000;
  47         int ret = 0;
  48
  49         netmask = htonl(netmask);
  50         while(msk) {
  51                 if (netmask & msk)
  52                         ret++;
  53                 msk >>= 1;
  54         }
  55         return ret;
  56 }
  57 #endif
  58
  59 #define NETMASK   0x01
  60 #define BROADCAST 0x02
  61 #define NETWORK   0x04
  62 #define NETPREFIX 0x08
  63 #define HOSTNAME  0x10
  64 #define SILENT    0x20
  65
  66
  67 int ipcalc_main(int argc, char **argv)
  68 {
  69         unsigned long mode;
  70
  71         unsigned long netmask;
  72         unsigned long broadcast;
  73         unsigned long network;
  74         unsigned long ipaddr;
  75         struct in_addr a;
  76
  77 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  78         unsigned long netprefix = 0;
  79         int have_netmask = 0;
  80         char *ipstr, *prefixstr;
  81 #endif
  82
  83         static const struct option long_options[] = {
  84                 {"netmask", no_argument, NULL, 'm'},
  85                 {"broadcast", no_argument, NULL, 'b'},
  86                 {"network", no_argument, NULL, 'n'},
  87 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  88                 {"prefix", no_argument, NULL, 'p'},
  89                 {"hostname", no_argument, NULL, 'h'},
  90                 {"silent", no_argument, NULL, 's'},
  91 #endif
  92                 {NULL, 0, NULL, 0}
  93         };
  94
  95         bb_applet_long_options = long_options;
  96         mode = bb_getopt_ulflags(argc, argv,
  97 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  98                                                           "mbnphs");
  99 #else
 100                                                           "mbn");
 101 #endif
 102         if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
 103                 if (argc - optind > 2) {
 104                         bb_show_usage();
 105                 }
 106         } else {
 107                 if (argc - optind != 1) {
 108                         bb_show_usage();
 109                 }
 110         }
 111
 112 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 113         prefixstr = ipstr = argv[optind];
 114
 115         while(*prefixstr) {
 116                 if (*prefixstr == '/') {
 117                         *prefixstr = (char)0;
 118                         prefixstr++;
 119                         if (*prefixstr) {
 120                                 unsigned int msk;
 121
 122                                 netprefix = atol(prefixstr);
 123                                 if (netprefix > 32) {
 124                                         IPCALC_MSG(bb_error_msg_and_die("bad IP prefix: %s\n", prefixstr),
 125                                                 exit(EXIT_FAILURE));
 126                                 }
 127                                 netmask = 0;
 128                                 msk = 0x80000000;
 129                                 while (netprefix > 0) {
 130                                         netmask |= msk;
 131                                         msk >>= 1;
 132                                                 netprefix--;
 133                                         }
 134                                         netmask = htonl(netmask);
 135                                 /* Even if it was 0, we will signify that we have a netmask. This allows */
 136                                 /* for specification of default routes, etc which have a 0 netmask/prefix */
 137                                 have_netmask = 1;
 138                         }
 139                         break;
 140                 }
 141                 prefixstr++;
 142         }
 143         ipaddr = inet_aton(ipstr, &a);
 144 #else
 145         ipaddr = inet_aton(argv[optind], &a);
 146 #endif
 147
 148         if (ipaddr == 0) {
 149                 IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[optind]),
 150                                    exit(EXIT_FAILURE));
 151         }
 152         ipaddr = a.s_addr;
 153
 154         if (argc - optind == 2) {
 155 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 156                if (have_netmask) {
 157                         IPCALC_MSG(bb_error_msg_and_die("Both prefix and netmask were specified, use one or the other.\n"),
 158                                 exit(EXIT_FAILURE));
 159                 }
 160
 161 #endif
 162                 netmask = inet_aton(argv[optind + 1], &a);
 163                 if (netmask == 0) {
 164                 IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[optind + 1]),
 165                                    exit(EXIT_FAILURE));
 166         }
 167                 netmask = a.s_addr;
 168         } else {
 169 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 170
 171                 if (!have_netmask)
 172 #endif
 173         /* JHC - If the netmask wasn't provided then calculate it */
 174                 netmask = get_netmask(ipaddr);
 175         }
 176
 177         if (mode & NETMASK) {
 178                 printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
 179         }
 180
 181         if (mode & BROADCAST) {
 182                 broadcast = (ipaddr & netmask) | ~netmask;
 183                 printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
 184         }
 185
 186         if (mode & NETWORK) {
 187                 network = ipaddr & netmask;
 188                 printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
 189         }
 190
 191 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 192         if (mode & NETPREFIX) {
 193                 printf("PREFIX=%i\n", get_prefix(netmask));
 194         }
 195
 196         if (mode & HOSTNAME) {
 197                 struct hostent *hostinfo;
 198                 int x;
 199
 200                 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
 201                 if (!hostinfo) {
 202                         IPCALC_MSG(bb_herror_msg_and_die(
 203                                 "cannot find hostname for %s", argv[optind]),);
 204                         exit(EXIT_FAILURE);
 205                 }
 206                 for (x = 0; hostinfo->h_name[x]; x++) {
 207                         hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
 208                 }
 209
 210                 printf("HOSTNAME=%s\n", hostinfo->h_name);
 211         }
 212 #endif
 213
 214         return EXIT_SUCCESS;
 215 }
 216
 217 /* END CODE */
 218 /*
 219 Local Variables:
 220 c-file-style: "linux"
 221 c-basic-offset: 4
 222 tab-width: 4
 223 End:
 224 */