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  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  13  */
  14
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <ctype.h>
  18 #include <getopt.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <arpa/inet.h>
  22
  23 #include "busybox.h"
  24
  25 #define IPCALC_MSG(CMD,ALTCMD) if (mode & SILENT) {ALTCMD;} else {CMD;}
  26
  27 #define CLASS_A_NETMASK ntohl(0xFF000000)
  28 #define CLASS_B_NETMASK ntohl(0xFFFF0000)
  29 #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
  30
  31 static unsigned long get_netmask(unsigned long ipaddr)
  32 {
  33         ipaddr = htonl(ipaddr);
  34
  35         if ((ipaddr & 0xC0000000) == 0xC0000000)
  36                 return CLASS_C_NETMASK;
  37         else if ((ipaddr & 0x80000000) == 0x80000000)
  38                 return CLASS_B_NETMASK;
  39         else if ((ipaddr & 0x80000000) == 0)
  40                 return CLASS_A_NETMASK;
  41         else
  42                 return 0;
  43 }
  44
  45 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  46 static int get_prefix(unsigned long netmask)
  47 {
  48         unsigned long msk = 0x80000000;
  49         int ret = 0;
  50
  51         netmask = htonl(netmask);
  52         while(msk) {
  53                 if (netmask & msk)
  54                         ret++;
  55                 msk >>= 1;
  56         }
  57         return ret;
  58 }
  59 #endif
  60
  61 #define NETMASK   0x01
  62 #define BROADCAST 0x02
  63 #define NETWORK   0x04
  64 #define NETPREFIX 0x08
  65 #define HOSTNAME  0x10
  66 #define SILENT    0x20
  67
  68
  69 int ipcalc_main(int argc, char **argv)
  70 {
  71         unsigned long mode;
  72
  73         in_addr_t netmask;
  74         in_addr_t broadcast;
  75         in_addr_t network;
  76         in_addr_t ipaddr;
  77         struct in_addr a;
  78
  79 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  80         unsigned long netprefix = 0;
  81         int have_netmask = 0;
  82         char *ipstr, *prefixstr;
  83 #endif
  84
  85 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
  86         static const struct option long_options[] = {
  87                 {"netmask",             no_argument, NULL, 'm'},
  88                 {"broadcast",   no_argument, NULL, 'b'},
  89                 {"network",             no_argument, NULL, 'n'},
  90 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  91                 {"prefix",              no_argument, NULL, 'p'},
  92                 {"hostname",    no_argument, NULL, 'h'},
  93                 {"silent",              no_argument, NULL, 's'},
  94 #endif
  95                 {NULL, 0, NULL, 0}
  96         };
  97
  98         bb_applet_long_options = long_options;
  99 #endif
 100         mode = bb_getopt_ulflags(argc, argv,
 101 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 102                         "mbnphs"
 103 #else
 104                         "mbn"
 105 #endif
 106                         );
 107
 108         argc -= optind;
 109         argv += optind;
 110         if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
 111                 if (argc > 2 || argc <= 0)
 112                         bb_show_usage();
 113         } else {
 114                 if (argc != 1)
 115                         bb_show_usage();
 116         }
 117
 118 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 119         prefixstr = ipstr = argv[0];
 120
 121         while(*prefixstr) {
 122                 if (*prefixstr == '/') {
 123                         *prefixstr = (char)0;
 124                         prefixstr++;
 125                         if (*prefixstr) {
 126                                 unsigned int msk;
 127
 128                                 if (safe_strtoul(prefixstr, &netprefix) || netprefix > 32) {
 129                                         IPCALC_MSG(bb_error_msg_and_die("bad IP prefix: %s\n", prefixstr),
 130                                                         exit(EXIT_FAILURE));
 131                                 }
 132                                 netmask = 0;
 133                                 msk = 0x80000000;
 134                                 while (netprefix > 0) {
 135                                         netmask |= msk;
 136                                         msk >>= 1;
 137                                         netprefix--;
 138                                 }
 139                                 netmask = htonl(netmask);
 140                                 /* Even if it was 0, we will signify that we have a netmask. This allows */
 141                                 /* for specification of default routes, etc which have a 0 netmask/prefix */
 142                                 have_netmask = 1;
 143                         }
 144                         break;
 145                 }
 146                 prefixstr++;
 147         }
 148         ipaddr = inet_aton(ipstr, &a);
 149 #else
 150         ipaddr = inet_aton(argv[0], &a);
 151 #endif
 152
 153         if (ipaddr == 0) {
 154                 IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[0]),
 155                                 exit(EXIT_FAILURE));
 156         }
 157         ipaddr = a.s_addr;
 158
 159         if (argc == 2) {
 160 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 161                 if (have_netmask) {
 162                         IPCALC_MSG(bb_error_msg_and_die("Both prefix and netmask were specified, use one or the other.\n"),
 163                                         exit(EXIT_FAILURE));
 164                 }
 165
 166 #endif
 167                 netmask = inet_aton(argv[1], &a);
 168                 if (netmask == 0) {
 169                         IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[1]),
 170                                         exit(EXIT_FAILURE));
 171                 }
 172                 netmask = a.s_addr;
 173         } else {
 174 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 175
 176                 if (!have_netmask)
 177 #endif
 178                         /* JHC - If the netmask wasn't provided then calculate it */
 179                         netmask = get_netmask(ipaddr);
 180         }
 181
 182         if (mode & NETMASK) {
 183                 printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
 184         }
 185
 186         if (mode & BROADCAST) {
 187                 broadcast = (ipaddr & netmask) | ~netmask;
 188                 printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
 189         }
 190
 191         if (mode & NETWORK) {
 192                 network = ipaddr & netmask;
 193                 printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
 194         }
 195
 196 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 197         if (mode & NETPREFIX) {
 198                 printf("PREFIX=%i\n", get_prefix(netmask));
 199         }
 200
 201         if (mode & HOSTNAME) {
 202                 struct hostent *hostinfo;
 203                 int x;
 204
 205                 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
 206                 if (!hostinfo) {
 207                         IPCALC_MSG(bb_herror_msg_and_die(
 208                                                 "cannot find hostname for %s", argv[0]),);
 209                         exit(EXIT_FAILURE);
 210                 }
 211                 for (x = 0; hostinfo->h_name[x]; x++) {
 212                         hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
 213                 }
 214
 215                 printf("HOSTNAME=%s\n", hostinfo->h_name);
 216         }
 217 #endif
 218
 219         return EXIT_SUCCESS;
 220 }