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 #define NETMASK   0x01
  44 #define BROADCAST 0x02
  45 #define NETWORK   0x04
  46 #define HOSTNAME  0x08
  47 #define SILENT    0x10
  48
  49 int ipcalc_main(int argc, char **argv)
  50 {
  51         unsigned long mode;
  52
  53         unsigned long netmask = 0;
  54         unsigned long broadcast;
  55         unsigned long network;
  56         unsigned long ipaddr;
  57
  58         static const struct option long_options[] = {
  59                 {"netmask", no_argument, NULL, 'n'},
  60                 {"broadcast", no_argument, NULL, 'b'},
  61                 {"network", no_argument, NULL, 'w'},
  62 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  63                 {"hostname", no_argument, NULL, 'h'},
  64                 {"silent", no_argument, NULL, 's'},
  65 #endif
  66                 {NULL, 0, NULL, 0}
  67         };
  68
  69         bb_applet_long_options = long_options;
  70         mode = bb_getopt_ulflags(argc, argv,
  71 #ifdef CONFIG_FEATURE_IPCALC_FANCY
  72                                                           "nbwhs");
  73 #else
  74                                                           "nbw");
  75 #endif
  76         if (mode & (BROADCAST | NETWORK)) {
  77                 if (argc - optind > 2) {
  78                         bb_show_usage();
  79                 }
  80         } else {
  81                 if (argc - optind != 1) {
  82                         bb_show_usage();
  83                 }
  84         }
  85
  86         ipaddr = inet_addr(argv[optind]);
  87
  88         if (ipaddr == INADDR_NONE) {
  89                 IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[optind]),
  90                                    exit(EXIT_FAILURE));
  91         }
  92
  93
  94         if (argc - optind == 2) {
  95                 netmask = inet_addr(argv[optind + 1]);
  96         }
  97
  98         if (ipaddr == INADDR_NONE) {
  99                 IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[optind + 1]),
 100                                    exit(EXIT_FAILURE));
 101         }
 102
 103         /* JHC - If the netmask wasn't provided then calculate it */
 104         if (!netmask) {
 105                 netmask = get_netmask(ipaddr);
 106         }
 107
 108         if (mode & NETMASK) {
 109                 printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
 110         }
 111
 112         if (mode & BROADCAST) {
 113                 broadcast = (ipaddr & netmask) | ~netmask;
 114                 printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
 115         }
 116
 117         if (mode & NETWORK) {
 118                 network = ipaddr & netmask;
 119                 printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
 120         }
 121 #ifdef CONFIG_FEATURE_IPCALC_FANCY
 122         if (mode & HOSTNAME) {
 123                 struct hostent *hostinfo;
 124                 int x;
 125
 126                 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
 127                 if (!hostinfo) {
 128                         IPCALC_MSG(bb_herror_msg_and_die(
 129                                 "cannot find hostname for %s", argv[optind]),);
 130                         exit(EXIT_FAILURE);
 131                 }
 132                 for (x = 0; hostinfo->h_name[x]; x++) {
 133                         hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
 134                 }
 135
 136                 printf("HOSTNAME=%s\n", hostinfo->h_name);
 137         }
 138 #endif
 139
 140         return EXIT_SUCCESS;
 141 }
 142
 143 /* END CODE */
 144 /*
 145 Local Variables:
 146 c-file-style: "linux"
 147 c-basic-offset: 4
 148 tab-width: 4
 149 End:
 150 */