networking/ipcalc.c

   1 /* vi: set sw=4 ts=4: */
   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 reimplementation of the ipcalc program
   9  * from Red Hat.  I didn't look at their source code, but there
  10  * is no denying that this is a loving reimplementation
  11  *
  12  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  13  */
  14
  15 #include "busybox.h"
  16 #include <ctype.h>
  17 #include <getopt.h>
  18 #include <sys/socket.h>
  19 #include <arpa/inet.h>
  20
  21 #define IPCALC_MSG(CMD,ALTCMD) if (mode & SILENT) {ALTCMD;} else {CMD;}
  22
  23 #define CLASS_A_NETMASK ntohl(0xFF000000)
  24 #define CLASS_B_NETMASK ntohl(0xFFFF0000)
  25 #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
  26
  27 static unsigned long get_netmask(unsigned long ipaddr)
  28 {
  29         ipaddr = htonl(ipaddr);
  30
  31         if ((ipaddr & 0xC0000000) == 0xC0000000)
  32                 return CLASS_C_NETMASK;
  33         else if ((ipaddr & 0x80000000) == 0x80000000)
  34                 return CLASS_B_NETMASK;
  35         else if ((ipaddr & 0x80000000) == 0)
  36                 return CLASS_A_NETMASK;
  37         else
  38                 return 0;
  39 }
  40
  41 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  42 static int get_prefix(unsigned long netmask)
  43 {
  44         unsigned long msk = 0x80000000;
  45         int ret = 0;
  46
  47         netmask = htonl(netmask);
  48         while(msk) {
  49                 if (netmask & msk)
  50                         ret++;
  51                 msk >>= 1;
  52         }
  53         return ret;
  54 }
  55 #else
  56 int get_prefix(unsigned long netmask);
  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 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
  67         static const struct option long_options[] = {
  68                 {"netmask",             no_argument, NULL, 'm'},
  69                 {"broadcast",   no_argument, NULL, 'b'},
  70                 {"network",             no_argument, NULL, 'n'},
  71 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  72                 {"prefix",              no_argument, NULL, 'p'},
  73                 {"hostname",    no_argument, NULL, 'h'},
  74                 {"silent",              no_argument, NULL, 's'},
  75 #endif
  76                 {NULL, 0, NULL, 0}
  77         };
  78 #else
  79 #define long_options 0
  80 #endif
  81
  82
  83
  84 int ipcalc_main(int argc, char **argv)
  85 {
  86         unsigned long mode;
  87         int have_netmask = 0;
  88         in_addr_t netmask, broadcast, network, ipaddr;
  89         struct in_addr a;
  90         char *ipstr;
  91
  92         if (ENABLE_FEATURE_IPCALC_LONG_OPTIONS)
  93                 bb_applet_long_options = long_options;
  94
  95         mode = bb_getopt_ulflags(argc, argv, "mbn" USE_FEATURE_IPCALC_FANCY("phs"));
  96
  97         argc -= optind;
  98         argv += optind;
  99         if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
 100                 if (argc > 2 || argc <= 0)
 101                         bb_show_usage();
 102         } else {
 103                 if (argc != 1)
 104                         bb_show_usage();
 105         }
 106
 107         ipstr = argv[0];
 108         if (ENABLE_FEATURE_IPCALC_FANCY) {
 109                 unsigned long netprefix = 0;
 110                 char *prefixstr;
 111
 112                 prefixstr = ipstr;
 113
 114                 while(*prefixstr) {
 115                         if (*prefixstr == '/') {
 116                                 *prefixstr = (char)0;
 117                                 prefixstr++;
 118                                 if (*prefixstr) {
 119                                         unsigned int msk;
 120
 121                                         if (safe_strtoul(prefixstr, &netprefix) || netprefix > 32) {
 122                                                 IPCALC_MSG(bb_error_msg_and_die("bad IP prefix: %s\n", prefixstr),
 123                                                                 exit(EXIT_FAILURE));
 124                                         }
 125                                         netmask = 0;
 126                                         msk = 0x80000000;
 127                                         while (netprefix > 0) {
 128                                                 netmask |= msk;
 129                                                 msk >>= 1;
 130                                                 netprefix--;
 131                                         }
 132                                         netmask = htonl(netmask);
 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         }
 142         ipaddr = inet_aton(ipstr, &a);
 143
 144         if (ipaddr == 0) {
 145                 IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[0]),
 146                                 exit(EXIT_FAILURE));
 147         }
 148         ipaddr = a.s_addr;
 149
 150         if (argc == 2) {
 151                 if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
 152                         IPCALC_MSG(bb_error_msg_and_die("Use prefix or netmask, not both.\n"),
 153                                         exit(EXIT_FAILURE));
 154                 }
 155
 156                 netmask = inet_aton(argv[1], &a);
 157                 if (netmask == 0) {
 158                         IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[1]),
 159                                         exit(EXIT_FAILURE));
 160                 }
 161                 netmask = a.s_addr;
 162         } else {
 163
 164                 /* JHC - If the netmask wasn't provided then calculate it */
 165                 if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
 166                         netmask = get_netmask(ipaddr);
 167         }
 168
 169         if (mode & NETMASK) {
 170                 printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
 171         }
 172
 173         if (mode & BROADCAST) {
 174                 broadcast = (ipaddr & netmask) | ~netmask;
 175                 printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
 176         }
 177
 178         if (mode & NETWORK) {
 179                 network = ipaddr & netmask;
 180                 printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
 181         }
 182
 183         if (ENABLE_FEATURE_IPCALC_FANCY) {
 184                 if (mode & NETPREFIX) {
 185                         printf("PREFIX=%i\n", get_prefix(netmask));
 186                 }
 187
 188                 if (mode & HOSTNAME) {
 189                         struct hostent *hostinfo;
 190                         int x;
 191
 192                         hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
 193                         if (!hostinfo) {
 194                                 IPCALC_MSG(bb_herror_msg_and_die(
 195                                                         "cannot find hostname for %s", argv[0]),);
 196                                 exit(EXIT_FAILURE);
 197                         }
 198                         for (x = 0; hostinfo->h_name[x]; x++) {
 199                                 hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
 200                         }
 201
 202                         printf("HOSTNAME=%s\n", hostinfo->h_name);
 203                 }
 204         }
 205
 206         return EXIT_SUCCESS;
 207 }