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 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
  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         in_addr_t netmask;
  72         in_addr_t broadcast;
  73         in_addr_t network;
  74         in_addr_t 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                         );
 103
 104         argc -= optind;
 105         argv += optind;
 106         if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
 107                 if (argc > 2 || argc <= 0)
 108                         bb_show_usage();
 109         } else {
 110                 if (argc != 1)
 111                         bb_show_usage();
 112         }
 113
 114 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 115         prefixstr = ipstr = argv[0];
 116
 117         while(*prefixstr) {
 118                 if (*prefixstr == '/') {
 119                         *prefixstr = (char)0;
 120                         prefixstr++;
 121                         if (*prefixstr) {
 122                                 unsigned int msk;
 123
 124                                 if (safe_strtoul(prefixstr, &netprefix) || netprefix > 32) {
 125                                         IPCALC_MSG(bb_error_msg_and_die("bad IP prefix: %s\n", prefixstr),
 126                                                         exit(EXIT_FAILURE));
 127                                 }
 128                                 netmask = 0;
 129                                 msk = 0x80000000;
 130                                 while (netprefix > 0) {
 131                                         netmask |= msk;
 132                                         msk >>= 1;
 133                                         netprefix--;
 134                                 }
 135                                 netmask = htonl(netmask);
 136                                 /* Even if it was 0, we will signify that we have a netmask. This allows */
 137                                 /* for specification of default routes, etc which have a 0 netmask/prefix */
 138                                 have_netmask = 1;
 139                         }
 140                         break;
 141                 }
 142                 prefixstr++;
 143         }
 144         ipaddr = inet_aton(ipstr, &a);
 145 #else
 146         ipaddr = inet_aton(argv[0], &a);
 147 #endif
 148
 149         if (ipaddr == 0) {
 150                 IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[0]),
 151                                 exit(EXIT_FAILURE));
 152         }
 153         ipaddr = a.s_addr;
 154
 155         if (argc == 2) {
 156 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 157                 if (have_netmask) {
 158                         IPCALC_MSG(bb_error_msg_and_die("Both prefix and netmask were specified, use one or the other.\n"),
 159                                         exit(EXIT_FAILURE));
 160                 }
 161
 162 #endif
 163                 netmask = inet_aton(argv[1], &a);
 164                 if (netmask == 0) {
 165                         IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[1]),
 166                                         exit(EXIT_FAILURE));
 167                 }
 168                 netmask = a.s_addr;
 169         } else {
 170 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 171
 172                 if (!have_netmask)
 173 #endif
 174                         /* JHC - If the netmask wasn't provided then calculate it */
 175                         netmask = get_netmask(ipaddr);
 176         }
 177
 178         if (mode & NETMASK) {
 179                 printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
 180         }
 181
 182         if (mode & BROADCAST) {
 183                 broadcast = (ipaddr & netmask) | ~netmask;
 184                 printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
 185         }
 186
 187         if (mode & NETWORK) {
 188                 network = ipaddr & netmask;
 189                 printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
 190         }
 191
 192 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 193         if (mode & NETPREFIX) {
 194                 printf("PREFIX=%i\n", get_prefix(netmask));
 195         }
 196
 197         if (mode & HOSTNAME) {
 198                 struct hostent *hostinfo;
 199                 int x;
 200
 201                 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
 202                 if (!hostinfo) {
 203                         IPCALC_MSG(bb_herror_msg_and_die(
 204                                                 "cannot find hostname for %s", argv[0]),);
 205                         exit(EXIT_FAILURE);
 206                 }
 207                 for (x = 0; hostinfo->h_name[x]; x++) {
 208                         hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
 209                 }
 210
 211                 printf("HOSTNAME=%s\n", hostinfo->h_name);
 212         }
 213 #endif
 214
 215         return EXIT_SUCCESS;
 216 }
 217
 218 /* END CODE */
 219 /*
 220 Local Variables:
 221 c-file-style: "linux"
 222 c-basic-offset: 4
 223 tab-width: 4
 224 End:
 225 */