git.maemo.org Git - busybox4maemo/blob - 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 <getopt.h>
  16 #include <sys/socket.h>
  17 #include <arpa/inet.h>
  18
  19 #include "libbb.h"
  20
  21 #define CLASS_A_NETMASK ntohl(0xFF000000)
  22 #define CLASS_B_NETMASK ntohl(0xFFFF0000)
  23 #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
  24
  25 static unsigned long get_netmask(unsigned long ipaddr)
  26 {
  27         ipaddr = htonl(ipaddr);
  28
  29         if ((ipaddr & 0xC0000000) == 0xC0000000)
  30                 return CLASS_C_NETMASK;
  31         else if ((ipaddr & 0x80000000) == 0x80000000)
  32                 return CLASS_B_NETMASK;
  33         else if ((ipaddr & 0x80000000) == 0)
  34                 return CLASS_A_NETMASK;
  35         else
  36                 return 0;
  37 }
  38
  39 #if ENABLE_FEATURE_IPCALC_FANCY
  40 static int get_prefix(unsigned long netmask)
  41 {
  42         unsigned long msk = 0x80000000;
  43         int ret = 0;
  44
  45         netmask = htonl(netmask);
  46         while (msk) {
  47                 if (netmask & msk)
  48                         ret++;
  49                 msk >>= 1;
  50         }
  51         return ret;
  52 }
  53 #else
  54 int get_prefix(unsigned long netmask);
  55 #endif
  56
  57
  58 #define NETMASK   0x01
  59 #define BROADCAST 0x02
  60 #define NETWORK   0x04
  61 #define NETPREFIX 0x08
  62 #define HOSTNAME  0x10
  63 #define SILENT    0x20
  64
  65 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
  66         static const char ipcalc_longopts[] ALIGN1 =
  67                 "netmask\0"   No_argument "m"
  68                 "broadcast\0" No_argument "b"
  69                 "network\0"   No_argument "n"
  70 # if ENABLE_FEATURE_IPCALC_FANCY
  71                 "prefix\0"    No_argument "p"
  72                 "hostname\0"  No_argument "h"
  73                 "silent\0"    No_argument "s"
  74 # endif
  75                 ;
  76 #endif
  77
  78 int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  79 int ipcalc_main(int argc, char **argv)
  80 {
  81         unsigned opt;
  82         int have_netmask = 0;
  83         in_addr_t netmask, broadcast, network, ipaddr;
  84         struct in_addr a;
  85         char *ipstr;
  86
  87 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
  88         applet_long_options = ipcalc_longopts;
  89 #endif
  90         opt = getopt32(argv, "mbn" USE_FEATURE_IPCALC_FANCY("phs"));
  91         argc -= optind;
  92         argv += optind;
  93         if (opt & (BROADCAST | NETWORK | NETPREFIX)) {
  94                 if (argc > 2 || argc <= 0)
  95                         bb_show_usage();
  96         } else {
  97                 if (argc != 1)
  98                         bb_show_usage();
  99         }
 100         if (opt & SILENT)
 101                 logmode = LOGMODE_NONE; /* Suppress error_msg() output */
 102
 103         ipstr = argv[0];
 104         if (ENABLE_FEATURE_IPCALC_FANCY) {
 105                 unsigned long netprefix = 0;
 106                 char *prefixstr;
 107
 108                 prefixstr = ipstr;
 109
 110                 while (*prefixstr) {
 111                         if (*prefixstr == '/') {
 112                                 *prefixstr = (char)0;
 113                                 prefixstr++;
 114                                 if (*prefixstr) {
 115                                         unsigned msk;
 116                                         netprefix = xatoul_range(prefixstr, 0, 32);
 117                                         netmask = 0;
 118                                         msk = 0x80000000;
 119                                         while (netprefix > 0) {
 120                                                 netmask |= msk;
 121                                                 msk >>= 1;
 122                                                 netprefix--;
 123                                         }
 124                                         netmask = htonl(netmask);
 125                                         /* Even if it was 0, we will signify that we have a netmask. This allows */
 126                                         /* for specification of default routes, etc which have a 0 netmask/prefix */
 127                                         have_netmask = 1;
 128                                 }
 129                                 break;
 130                         }
 131                         prefixstr++;
 132                 }
 133         }
 134         ipaddr = inet_aton(ipstr, &a);
 135
 136         if (ipaddr == 0) {
 137                 bb_error_msg_and_die("bad IP address: %s", argv[0]);
 138         }
 139         ipaddr = a.s_addr;
 140
 141         if (argc == 2) {
 142                 if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
 143                         bb_error_msg_and_die("use prefix or netmask, not both");
 144                 }
 145
 146                 netmask = inet_aton(argv[1], &a);
 147                 if (netmask == 0) {
 148                         bb_error_msg_and_die("bad netmask: %s", argv[1]);
 149                 }
 150                 netmask = a.s_addr;
 151         } else {
 152
 153                 /* JHC - If the netmask wasn't provided then calculate it */
 154                 if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
 155                         netmask = get_netmask(ipaddr);
 156         }
 157
 158         if (opt & NETMASK) {
 159                 printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
 160         }
 161
 162         if (opt & BROADCAST) {
 163                 broadcast = (ipaddr & netmask) | ~netmask;
 164                 printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
 165         }
 166
 167         if (opt & NETWORK) {
 168                 network = ipaddr & netmask;
 169                 printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
 170         }
 171
 172         if (ENABLE_FEATURE_IPCALC_FANCY) {
 173                 if (opt & NETPREFIX) {
 174                         printf("PREFIX=%i\n", get_prefix(netmask));
 175                 }
 176
 177                 if (opt & HOSTNAME) {
 178                         struct hostent *hostinfo;
 179                         int x;
 180
 181                         hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
 182                         if (!hostinfo) {
 183                                 bb_herror_msg_and_die("cannot find hostname for %s", argv[0]);
 184                         }
 185                         for (x = 0; hostinfo->h_name[x]; x++) {
 186                                 hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
 187                         }
 188
 189                         printf("HOSTNAME=%s\n", hostinfo->h_name);
 190                 }
 191         }
 192
 193         return EXIT_SUCCESS;
 194 }