rarp.c

   1 /*
   2  * rarp               This file contains an implementation of the command
   3  *              that maintains the kernel's RARP cache.  It is derived
   4  *              from Fred N. van Kempen's arp command.
   5  *
   6  * Version:     $Id: rarp.c,v 1.5 1999/01/05 20:53:02 philip Exp $
   7  *
   8  * Usage:       rarp -d hostname                      Delete entry
   9  *              rarp -s hostname ethernet_address     Add entry
  10  *              rarp -a                               Print entries
  11  *              rarp -f                               Add frop /etc/ethers
  12  *
  13  * Rewritten: Phil Blundell <Philip.Blundell@pobox.com>  1997-08-03
  14  * gettext instead of catgets: Arnaldo Carvalho de Melo <acme@conectiva.com.br> 1998-06-29
  15  * 1998-01-01 Bernd Eckenfels   reorganised usage()
  16  *
  17  */
  18
  19 #include <sys/types.h>
  20 #include <sys/socket.h>
  21 #include <sys/ioctl.h>
  22 #include <netinet/in.h>
  23 #include <arpa/inet.h>
  24 #include <net/if.h>
  25 #include <net/if_arp.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <errno.h>
  29 #include <fcntl.h>
  30 #include <netdb.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <getopt.h>
  34
  35 #define DFLT_HW "ether"
  36
  37 #include "config.h"
  38 #include "intl.h"
  39 #include "net-support.h"
  40 #include "version.h"
  41 #include "pathnames.h"
  42
  43 static char no_rarp_message[] = N_("This kernel does not support RARP.\n");
  44
  45 static char version_string[] = RELEASE "\nrarp 1.02 (1998-06-30)\n";
  46
  47 static struct hwtype *hardware = NULL;
  48
  49 /* Delete an entry from the RARP cache. */
  50 static int rarp_delete(int fd, struct hostent *hp)
  51 {
  52     struct arpreq req;
  53     struct sockaddr_in *si;
  54     unsigned int found = 0;
  55     char **addr;
  56
  57     /* The host can have more than one address, so we loop on them. */
  58     for (addr = hp->h_addr_list; *addr != NULL; addr++) {
  59         memset((char *) &req, 0, sizeof(req));
  60         si = (struct sockaddr_in *) &req.arp_pa;
  61         si->sin_family = hp->h_addrtype;
  62         memcpy((char *) &si->sin_addr, *addr, hp->h_length);
  63
  64         /* Call the kernel. */
  65         if (ioctl(fd, SIOCDRARP, &req) == 0) {
  66             found++;
  67         } else {
  68             switch (errno) {
  69             case ENXIO:
  70                 break;
  71             case ENODEV:
  72                 fputs(_(no_rarp_message), stderr);
  73                 return 1;
  74             default:
  75                 perror("SIOCDRARP");
  76                 return 1;
  77             }
  78         }
  79     }
  80
  81     if (found == 0)
  82         printf(_("no RARP entry for %s.\n"), hp->h_name);
  83     return 0;
  84 }
  85
  86
  87 /* Set an entry in the RARP cache. */
  88 static int rarp_set(int fd, struct hostent *hp, char *hw_addr)
  89 {
  90     struct arpreq req;
  91     struct sockaddr_in *si;
  92     struct sockaddr sap;
  93
  94     if (hardware->input(hw_addr, &sap)) {
  95         fprintf(stderr, _("%s: bad hardware address\n"), hw_addr);
  96         return 1;
  97     }
  98     /* Clear and fill in the request block. */
  99     memset((char *) &req, 0, sizeof(req));
 100     si = (struct sockaddr_in *) &req.arp_pa;
 101     si->sin_family = hp->h_addrtype;
 102     memcpy((char *) &si->sin_addr, hp->h_addr_list[0], hp->h_length);
 103     req.arp_ha.sa_family = hardware->type;
 104     memcpy(req.arp_ha.sa_data, sap.sa_data, hardware->alen);
 105
 106     /* Call the kernel. */
 107     if (ioctl(fd, SIOCSRARP, &req) < 0) {
 108         if (errno == ENODEV)
 109             fputs(_(no_rarp_message), stderr);
 110         else
 111             perror("SIOCSRARP");
 112         return 1;
 113     }
 114     return 0;
 115 }
 116
 117 /* Process an EtherFile */
 118 static int rarp_file(int fd, const char *name)
 119 {
 120     char buff[1024];
 121     char *host, *addr;
 122     int linenr;
 123     FILE *fp;
 124     struct hostent *hp;
 125
 126     if ((fp = fopen(name, "r")) == NULL) {
 127         fprintf(stderr, _("rarp: cannot open file %s:%s.\n"), name, strerror(errno));
 128         return -1;
 129     }
 130     /* Read the lines in the file. */
 131     linenr = 0;
 132     while (fgets(buff, sizeof(buff), fp)) {
 133         ++linenr;
 134         if (buff[0] == '#' || buff[0] == '\0')
 135             continue;
 136         if ((addr = strtok(buff, "\n \t")) == NULL)
 137             continue;
 138         if ((host = strtok(NULL, "\n \t")) == NULL) {
 139             fprintf(stderr, _("rarp: format error at %s:%u\n"), name, linenr);
 140             continue;
 141         }
 142         if ((hp = gethostbyname(host)) == NULL) {
 143             fprintf(stderr, _("rarp: %s: unknown host\n"), host);
 144         }
 145         if (rarp_set(fd, hp, addr) != 0) {
 146             fprintf(stderr, _("rarp: cannot set entry from %s:%u\n"), name, linenr);
 147         }
 148     }
 149
 150     (void) fclose(fp);
 151     return 0;
 152 }
 153
 154 static int display_cache(void)
 155 {
 156     FILE *fd = fopen(_PATH_PROCNET_RARP, "r");
 157     char buffer[256];
 158     if (fd == NULL) {
 159         if (errno == ENOENT)
 160             fputs(_(no_rarp_message), stderr);
 161         else
 162             perror(_PATH_PROCNET_RARP);
 163         return 1;
 164     }
 165     while (feof(fd) == 0) {
 166         if (fgets(buffer, 255, fd))
 167             fputs(buffer, stdout);
 168     }
 169     fclose(fd);
 170     return 0;
 171 }
 172
 173 static void usage(void)
 174 {
 175     fprintf(stderr, _("Usage: rarp -a                               list entries in cache.\n"));
 176     fprintf(stderr, _("       rarp -d <hostname>                    delete entry from cache.\n"));
 177     fprintf(stderr, _("       rarp [<HW>] -s <hostname> <hwaddr>    add entry to cache.\n"));
 178     fprintf(stderr, _("       rarp -f                               add entries from /etc/ethers.\n"));
 179     fprintf(stderr, _("       rarp -V                               display program version.\n\n"));
 180
 181     fprintf(stderr, _("  <HW>=Use '-H <hw>' to specify hardware address type. Default: %s\n"), DFLT_HW);
 182     fprintf(stderr, _("  List of possible hardware types (which support ARP):\n"));
 183     print_hwlist(1); /* 1 = ARPable */
 184     exit(E_USAGE);
 185 }
 186
 187 #define MODE_DISPLAY   1
 188 #define MODE_DELETE    2
 189 #define MODE_SET       3
 190 #define MODE_ETHERS    4
 191
 192 static struct option longopts[] =
 193 {
 194     {"version", 0, NULL, 'V'},
 195     {"verbose", 0, NULL, 'v'},
 196     {"list", 0, NULL, 'a'},
 197     {"set", 0, NULL, 's'},
 198     {"delete", 0, NULL, 'd'},
 199     {"help", 0, NULL, 'h'},
 200     {NULL, 0, NULL, 0}
 201 };
 202
 203 int main(int argc, char **argv)
 204 {
 205     int result = 0, mode = 0, c, nargs = 0, verbose = 0;
 206     char *args[3];
 207     struct hostent *hp;
 208     int fd;
 209
 210 #if I18N
 211     bindtextdomain("net-tools", "/usr/share/locale");
 212     textdomain("net-tools");
 213 #endif
 214
 215     /* Get a default hardware type.  */
 216     hardware = get_hwtype(DFLT_HW);
 217
 218     do {
 219         c = getopt_long(argc, argv, "-ht:aHdsVvf", longopts, NULL);
 220         switch (c) {
 221         case EOF:
 222             break;
 223         case 'h':
 224             usage();
 225         case 'V':
 226             fprintf(stderr, version_string);
 227             exit(E_VERSION);
 228             break;
 229         case 'v':
 230             verbose++;
 231             break;
 232         case 'a':
 233         case 's':
 234         case 'd':
 235             if (mode) {
 236                 fprintf(stderr, _("%s: illegal option mix.\n"), argv[0]);
 237                 usage();
 238             } else {
 239                 mode = (c == 'a' ? MODE_DISPLAY : (c == 'd' ? MODE_DELETE : MODE_SET));
 240             }
 241             break;
 242         case 'f':
 243             mode = MODE_ETHERS;
 244             break;
 245         case 'H':
 246         case 't':
 247             if (optarg) {
 248                 hardware = get_hwtype(optarg);
 249             } else {
 250                 usage();
 251             }
 252             break;
 253         case 1:
 254             if (nargs == 2) {
 255                 usage();
 256                 exit(1);
 257             } else {
 258                 args[nargs++] = optarg;
 259             }
 260             break;
 261         default:
 262             usage();
 263         }
 264     } while (c != EOF);
 265
 266     if (hardware == NULL) {
 267         fprintf(stderr, _("rarp: %s: unknown hardware type.\n"), optarg);
 268         exit(1);
 269     }
 270     switch (mode) {
 271     case 0:
 272         usage();
 273
 274     case MODE_DISPLAY:
 275         if (nargs != (mode - 1)) {
 276             usage();
 277         }
 278         result = display_cache();
 279         break;
 280
 281     case MODE_DELETE:
 282     case MODE_SET:
 283         if (nargs != (mode - 1)) {
 284             usage();
 285         }
 286         if ((hp = gethostbyname(args[0])) == NULL) {
 287             fprintf(stderr, _("rarp: %s: unknown host\n"), args[0]);
 288             exit(1);
 289         }
 290         if (fd = socket(PF_INET, SOCK_DGRAM, 0), fd < 0) {
 291             perror("socket");
 292             exit(1);
 293         }
 294         result = (mode == MODE_DELETE) ? rarp_delete(fd, hp) : rarp_set(fd, hp, args[1]);
 295         close(fd);
 296         break;
 297
 298     case MODE_ETHERS:
 299         if (nargs != 0 && nargs != 1)
 300             usage();
 301         if (fd = socket(PF_INET, SOCK_DGRAM, 0), fd < 0) {
 302             perror("socket");
 303             exit(1);
 304         }
 305         result = rarp_file(fd, nargs ? args[0] : _PATH_ETHERS);
 306         close(fd);
 307
 308     }
 309     exit(result);
 310 }