source/lib/netmask.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    code to query kernel netmask
   5    Copyright (C) Andrew Tridgell 1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22
  23 /* working out the netmask for an interface is an incredibly non-portable
  24    thing. We have several possible implementations below, and autoconf
  25    tries each of them to see what works
  26
  27    Note that this file does _not_ include includes.h. That is so this code
  28    can be called directly from the autoconf tests. That also means
  29    this code cannot use any of the normal Samba debug stuff or defines.
  30    This is standalone code.
  31
  32 */
  33
  34 #ifndef AUTOCONF
  35 #include "config.h"
  36 #endif
  37
  38 #ifdef HAVE_NETMASK_IFCONF
  39
  40 #include <stdio.h>
  41 #include <unistd.h>
  42 #include <sys/types.h>
  43 #include <sys/socket.h>
  44 #include <netinet/in.h>
  45 #include <arpa/inet.h>
  46 #include <netdb.h>
  47 #include <sys/ioctl.h>
  48 #include <net/if.h>
  49
  50 #ifndef SIOCGIFCONF
  51 #include <sys/sockio.h>
  52 #endif
  53
  54 /*
  55  * Prototype for gcc in fussy mode.
  56  */
  57
  58 int get_netmask(struct in_addr *ipaddr, struct in_addr *nmask);
  59
  60 /****************************************************************************
  61   get the netmask address for a local interface
  62 ****************************************************************************/
  63 int get_netmask(struct in_addr *ipaddr, struct in_addr *nmask)
  64 {
  65         struct ifconf ifc;
  66         char buff[2048];
  67         int fd, i, n;
  68         struct ifreq *ifr=NULL;
  69
  70         if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
  71 #ifdef DEBUG
  72                 fprintf(stderr,"socket failed\n");
  73 #endif
  74                 return -1;
  75         }
  76
  77         ifc.ifc_len = sizeof(buff);
  78         ifc.ifc_buf = buff;
  79         if (ioctl(fd, SIOCGIFCONF, &ifc) != 0) {
  80 #ifdef DEBUG
  81                 fprintf(stderr,"SIOCGIFCONF failed\n");
  82 #endif
  83                 close(fd);
  84                 return -1;
  85         }
  86
  87         ifr = ifc.ifc_req;
  88
  89         n = ifc.ifc_len / sizeof(struct ifreq);
  90
  91 #ifdef DEBUG
  92         fprintf(stderr,"%d interfaces - looking for %s\n",
  93                 n, inet_ntoa(*ipaddr));
  94 #endif
  95
  96         /* Loop through interfaces, looking for given IP address */
  97         for (i=n-1;i>=0;i--) {
  98                 if (ioctl(fd, SIOCGIFADDR, &ifr[i]) != 0) {
  99 #ifdef DEBUG
 100                         fprintf(stderr,"SIOCGIFADDR failed\n");
 101 #endif
 102                         continue;
 103                 }
 104
 105 #ifdef DEBUG
 106                 fprintf(stderr,"interface %s\n",
 107                         inet_ntoa((*(struct sockaddr_in *)&ifr[i].ifr_addr).sin_addr));
 108 #endif
 109                 if (ipaddr->s_addr !=
 110                     (*(struct sockaddr_in *)&ifr[i].ifr_addr).sin_addr.s_addr) {
 111                         continue;
 112                 }
 113
 114                 if (ioctl(fd, SIOCGIFNETMASK, &ifr[i]) != 0) {
 115 #ifdef DEBUG
 116                         fprintf(stderr,"SIOCGIFNETMASK failed\n");
 117 #endif
 118                         close(fd);
 119                         return -1;
 120                 }
 121                 close(fd);
 122                 (*nmask) = ((struct sockaddr_in *)&ifr[i].ifr_addr)->sin_addr;
 123 #ifdef DEBUG
 124                 fprintf(stderr,"netmask %s\n", inet_ntoa(*nmask));
 125 #endif
 126                 return 0;
 127         }
 128
 129 #ifdef DEBUG
 130         fprintf(stderr,"interface not found\n");
 131 #endif
 132
 133         close(fd);
 134         return -1;
 135 }
 136
 137 #elif defined(HAVE_NETMASK_IFREQ)
 138
 139 #include <stdio.h>
 140 #include <sys/types.h>
 141 #include <sys/socket.h>
 142 #include <netinet/in.h>
 143 #include <arpa/inet.h>
 144 #include <netdb.h>
 145 #include <sys/ioctl.h>
 146 #include <net/if.h>
 147
 148 #ifndef SIOCGIFCONF
 149 #include <sys/sockio.h>
 150 #endif
 151
 152 #ifndef I_STR
 153 #include <sys/stropts.h>
 154 #endif
 155
 156
 157 /****************************************************************************
 158 this should cover most of the rest of systems
 159 ****************************************************************************/
 160  int get_netmask(struct in_addr *ipaddr, struct in_addr *nmask)
 161 {
 162         struct ifreq ifreq;
 163         struct strioctl strioctl;
 164         struct ifconf *ifc;
 165         char buff[2048];
 166         int fd, i, n;
 167         struct ifreq *ifr=NULL;
 168
 169         if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
 170 #ifdef DEBUG
 171                 fprintf(stderr,"socket failed\n");
 172 #endif
 173                 return -1;
 174         }
 175
 176         ifc = (struct ifconf *)buff;
 177         ifc->ifc_len = BUFSIZ - sizeof(struct ifconf);
 178         strioctl.ic_cmd = SIOCGIFCONF;
 179         strioctl.ic_dp  = (char *)ifc;
 180         strioctl.ic_len = sizeof(buff);
 181         if (ioctl(fd, I_STR, &strioctl) < 0) {
 182 #ifdef DEBUG
 183                 fprintf(stderr,"SIOCGIFCONF failed\n");
 184 #endif
 185                 close(fd);
 186                 return -1;
 187         }
 188
 189         ifr = (struct ifreq *)ifc->ifc_req;
 190
 191         /* Loop through interfaces, looking for given IP address */
 192         n = ifc->ifc_len / sizeof(struct ifreq);
 193
 194         for (i = 0; i<n; i++, ifr++) {
 195 #ifdef DEBUG
 196                 fprintf(stderr,"interface %s\n",
 197                         inet_ntoa((*(struct sockaddr_in *)&ifr->ifr_addr).sin_addr.s_addr));
 198 #endif
 199                 if (ipaddr->s_addr ==
 200                     (*(struct sockaddr_in *) &ifr->ifr_addr).sin_addr.s_addr) {
 201                         break;
 202                 }
 203         }
 204
 205 #ifdef DEBUG
 206         if (i == n) {
 207                 fprintf(stderr,"interface not found\n");
 208                 close(fd);
 209                 return -1;
 210         }
 211 #endif
 212
 213         ifreq = *ifr;
 214
 215         strioctl.ic_cmd = SIOCGIFNETMASK;
 216         strioctl.ic_dp  = (char *)&ifreq;
 217         strioctl.ic_len = sizeof(struct ifreq);
 218         if (ioctl(fd, I_STR, &strioctl) != 0) {
 219 #ifdef DEBUG
 220                 fprintf(stderr,"Failed SIOCGIFNETMASK\n");
 221 #endif
 222                 close(fd);
 223                 return -1;
 224         }
 225
 226         close(fd);
 227         *nmask = ((struct sockaddr_in *)&ifreq.ifr_addr)->sin_addr;
 228 #ifdef DEBUG
 229         fprintf(stderr,"netmask %s\n", inet_ntoa(*nmask));
 230 #endif
 231         return 0;
 232 }
 233
 234 #elif defined(HAVE_NETMASK_AIX)
 235
 236 #include <stdio.h>
 237 #include <sys/types.h>
 238 #include <sys/socket.h>
 239 #include <netinet/in.h>
 240 #include <arpa/inet.h>
 241 #include <netdb.h>
 242 #include <sys/ioctl.h>
 243 #include <net/if.h>
 244
 245 #ifndef SIOCGIFCONF
 246 #include <sys/sockio.h>
 247 #endif
 248
 249 /****************************************************************************
 250 this one is for AIX
 251 ****************************************************************************/
 252  int get_netmask(struct in_addr *ipaddr, struct in_addr *nmask)
 253 {
 254         char buff[2048];
 255         int fd, i, n;
 256         struct ifconf ifc;
 257         struct ifreq *ifr=NULL;
 258
 259         if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
 260 #ifdef DEBUG
 261                 fprintf(stderr,"socket failed\n");
 262 #endif
 263                 return -1;
 264         }
 265
 266
 267         ifc.ifc_len = sizeof(buff);
 268         ifc.ifc_buf = buff;
 269
 270         if (ioctl(fd, SIOCGIFCONF, &ifc) != 0) {
 271 #ifdef DEBUG
 272                 fprintf(stderr,"SIOCGIFCONF failed\n");
 273 #endif
 274                 close(fd);
 275                 return -1;
 276         }
 277
 278         ifr = ifc.ifc_req;
 279         /* Loop through interfaces, looking for given IP address */
 280         i = ifc.ifc_len;
 281         while (i > 0) {
 282 #ifdef DEBUG
 283                 fprintf(stderr,"interface %s\n",
 284                         inet_ntoa((*(struct sockaddr_in *)&ifr->ifr_addr).sin_addr));
 285 #endif
 286                 if (ipaddr->s_addr ==
 287                     (*(struct sockaddr_in *) &ifr->ifr_addr).sin_addr.s_addr) {
 288                         break;
 289                 }
 290                 i -= ifr->ifr_addr.sa_len + IFNAMSIZ;
 291                 ifr = (struct ifreq*) ((char*) ifr + ifr->ifr_addr.sa_len +
 292                                        IFNAMSIZ);
 293         }
 294
 295
 296 #ifdef DEBUG
 297         if (i <= 0) {
 298                 fprintf(stderr,"interface not found\n");
 299                 close(fd);
 300                 return -1;
 301         }
 302 #endif
 303
 304         if (ioctl(fd, SIOCGIFNETMASK, ifr) != 0) {
 305 #ifdef DEBUG
 306                 fprintf(stderr,"SIOCGIFNETMASK failed\n");
 307 #endif
 308                 close(fd);
 309                 return -1;
 310         }
 311
 312         close(fd);
 313
 314         (*nmask) = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
 315 #ifdef DEBUG
 316         fprintf(stderr,"netmask %s\n", inet_ntoa(*nmask));
 317 #endif
 318         return 0;
 319 }
 320
 321 #else /* a dummy version */
 322 struct in_addr; /* it may not have been declared before */
 323  int get_netmask(struct in_addr *ipaddr, struct in_addr *nmask)
 324 {
 325         return -1;
 326 }
 327 #endif
 328
 329
 330 #ifdef AUTOCONF
 331 /* this is the autoconf driver to test get_netmask() */
 332
 333  main()
 334 {
 335         char buf[1024];
 336         struct hostent *hp;
 337         struct in_addr ip, nmask;
 338
 339         if (gethostname(buf, sizeof(buf)-1) != 0) {
 340                 fprintf(stderr,"gethostname failed\n");
 341                 exit(1);
 342         }
 343
 344         hp = gethostbyname(buf);
 345
 346         if (!hp) {
 347                 fprintf(stderr,"gethostbyname failed\n");
 348                 exit(1);
 349         }
 350
 351         memcpy((char *)&ip, (char *)hp->h_addr, hp->h_length);
 352
 353         if (get_netmask(&ip, &nmask) == 0) exit(0);
 354
 355         fprintf(stderr,"get_netmask failed\n");
 356         exit(1);
 357 }
 358 #endif