source/lib/interfaces.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 2.0
   4    return a list of network interfaces
   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 interfaces for a OS 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 #include <unistd.h>
  35 #include <stdio.h>
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38 #include <netinet/in.h>
  39 #include <arpa/inet.h>
  40 #include <netdb.h>
  41 #include <sys/ioctl.h>
  42 #include <net/if.h>
  43
  44 #ifdef AUTOCONF_TEST
  45 struct iface_struct {
  46         char name[16];
  47         struct in_addr ip;
  48         struct in_addr netmask;
  49 };
  50 #else
  51 #include "config.h"
  52 #include "interfaces.h"
  53 #endif
  54
  55 #ifdef HAVE_SYS_TIME_H
  56 #include <sys/time.h>
  57 #endif
  58
  59 #ifndef SIOCGIFCONF
  60 #ifdef HAVE_SYS_SOCKIO_H
  61 #include <sys/sockio.h>
  62 #endif
  63 #endif
  64
  65 #ifdef HAVE_STDLIB_H
  66 #include <stdlib.h>
  67 #endif
  68
  69 #ifdef HAVE_STRING_H
  70 #include <string.h>
  71 #endif
  72
  73 #ifdef HAVE_STRINGS_H
  74 #include <strings.h>
  75 #endif
  76
  77 #ifdef __COMPAR_FN_T
  78 #define QSORT_CAST (__compar_fn_t)
  79 #endif
  80
  81 #ifndef QSORT_CAST
  82 #define QSORT_CAST (int (*)(const void *, const void *))
  83 #endif
  84
  85 #if HAVE_IFACE_IFCONF
  86
  87 /* this works for Linux 2.2, Solaris 2.5, SunOS4, HPUX 10.20, OSF1
  88    V4.0, Ultrix 4.4, SCO Unix 3.2, IRIX 6.4 and FreeBSD 3.2.
  89
  90    It probably also works on any BSD style system.  */
  91
  92 /****************************************************************************
  93   get the netmask address for a local interface
  94 ****************************************************************************/
  95 static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
  96 {
  97         struct ifconf ifc;
  98         char buff[8192];
  99         int fd, i, n;
 100         struct ifreq *ifr=NULL;
 101         int total = 0;
 102         struct in_addr ipaddr;
 103         struct in_addr nmask;
 104         char *iname;
 105
 106         if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
 107                 return -1;
 108         }
 109
 110         ifc.ifc_len = sizeof(buff);
 111         ifc.ifc_buf = buff;
 112
 113         if (ioctl(fd, SIOCGIFCONF, &ifc) != 0) {
 114                 close(fd);
 115                 return -1;
 116         }
 117
 118         ifr = ifc.ifc_req;
 119
 120         n = ifc.ifc_len / sizeof(struct ifreq);
 121
 122         /* Loop through interfaces, looking for given IP address */
 123         for (i=n-1;i>=0 && total < max_interfaces;i--) {
 124                 if (ioctl(fd, SIOCGIFADDR, &ifr[i]) != 0) {
 125                         continue;
 126                 }
 127
 128                 iname = ifr[i].ifr_name;
 129                 ipaddr = (*(struct sockaddr_in *)&ifr[i].ifr_addr).sin_addr;
 130
 131                 if (ioctl(fd, SIOCGIFFLAGS, &ifr[i]) != 0) {
 132                         continue;
 133                 }
 134
 135                 if (!(ifr[i].ifr_flags & IFF_UP)) {
 136                         continue;
 137                 }
 138
 139                 if (ioctl(fd, SIOCGIFNETMASK, &ifr[i]) != 0) {
 140                         continue;
 141                 }
 142
 143                 nmask = ((struct sockaddr_in *)&ifr[i].ifr_addr)->sin_addr;
 144
 145                 strncpy(ifaces[total].name, iname, sizeof(ifaces[total].name)-1);
 146                 ifaces[total].name[sizeof(ifaces[total].name)-1] = 0;
 147                 ifaces[total].ip = ipaddr;
 148                 ifaces[total].netmask = nmask;
 149                 total++;
 150         }
 151
 152         close(fd);
 153
 154         return total;
 155 }
 156
 157 #elif HAVE_IFACE_IFREQ
 158
 159 #ifndef I_STR
 160 #include <sys/stropts.h>
 161 #endif
 162
 163 /****************************************************************************
 164 this should cover most of the streams based systems
 165 Thanks to Andrej.Borsenkow@mow.siemens.ru for several ideas in this code
 166 ****************************************************************************/
 167 static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
 168 {
 169         struct ifreq ifreq;
 170         struct strioctl strioctl;
 171         char buff[8192];
 172         int fd, i, n;
 173         struct ifreq *ifr=NULL;
 174         int total = 0;
 175         struct in_addr ipaddr;
 176         struct in_addr nmask;
 177         char *iname;
 178
 179         if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
 180                 return -1;
 181         }
 182
 183         strioctl.ic_cmd = SIOCGIFCONF;
 184         strioctl.ic_dp  = buff;
 185         strioctl.ic_len = sizeof(buff);
 186         if (ioctl(fd, I_STR, &strioctl) < 0) {
 187                 close(fd);
 188                 return -1;
 189         }
 190
 191         /* we can ignore the possible sizeof(int) here as the resulting
 192            number of interface structures won't change */
 193         n = strioctl.ic_len / sizeof(struct ifreq);
 194
 195         /* we will assume that the kernel returns the length as an int
 196            at the start of the buffer if the offered size is a
 197            multiple of the structure size plus an int */
 198         if (n*sizeof(struct ifreq) + sizeof(int) == strioctl.ic_len) {
 199                 ifr = (struct ifreq *)(buff + sizeof(int));
 200         } else {
 201                 ifr = (struct ifreq *)buff;
 202         }
 203
 204         /* Loop through interfaces */
 205
 206         for (i = 0; i<n && total < max_interfaces; i++) {
 207                 ifreq = ifr[i];
 208
 209                 strioctl.ic_cmd = SIOCGIFFLAGS;
 210                 strioctl.ic_dp  = (char *)&ifreq;
 211                 strioctl.ic_len = sizeof(struct ifreq);
 212                 if (ioctl(fd, I_STR, &strioctl) != 0) {
 213                         continue;
 214                 }
 215
 216                 if (!(ifreq.ifr_flags & IFF_UP)) {
 217                         continue;
 218                 }
 219
 220                 strioctl.ic_cmd = SIOCGIFADDR;
 221                 strioctl.ic_dp  = (char *)&ifreq;
 222                 strioctl.ic_len = sizeof(struct ifreq);
 223                 if (ioctl(fd, I_STR, &strioctl) != 0) {
 224                         continue;
 225                 }
 226
 227                 ipaddr = (*(struct sockaddr_in *) &ifreq.ifr_addr).sin_addr;
 228                 iname = ifreq.ifr_name;
 229
 230                 strioctl.ic_cmd = SIOCGIFNETMASK;
 231                 strioctl.ic_dp  = (char *)&ifreq;
 232                 strioctl.ic_len = sizeof(struct ifreq);
 233                 if (ioctl(fd, I_STR, &strioctl) != 0) {
 234                         continue;
 235                 }
 236
 237                 nmask = ((struct sockaddr_in *)&ifreq.ifr_addr)->sin_addr;
 238
 239                 strncpy(ifaces[total].name, iname, sizeof(ifaces[total].name)-1);
 240                 ifaces[total].name[sizeof(ifaces[total].name)-1] = 0;
 241                 ifaces[total].ip = ipaddr;
 242                 ifaces[total].netmask = nmask;
 243
 244                 total++;
 245         }
 246
 247         close(fd);
 248
 249         return total;
 250 }
 251
 252 #elif HAVE_IFACE_AIX
 253
 254 /****************************************************************************
 255 this one is for AIX (tested on 4.2)
 256 ****************************************************************************/
 257 static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
 258 {
 259         char buff[8192];
 260         int fd, i;
 261         struct ifconf ifc;
 262         struct ifreq *ifr=NULL;
 263         struct in_addr ipaddr;
 264         struct in_addr nmask;
 265         char *iname;
 266         int total = 0;
 267
 268         if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
 269                 return -1;
 270         }
 271
 272
 273         ifc.ifc_len = sizeof(buff);
 274         ifc.ifc_buf = buff;
 275
 276         if (ioctl(fd, SIOCGIFCONF, &ifc) != 0) {
 277                 close(fd);
 278                 return -1;
 279         }
 280
 281         ifr = ifc.ifc_req;
 282
 283         /* Loop through interfaces */
 284         i = ifc.ifc_len;
 285
 286         while (i > 0 && total < max_interfaces) {
 287                 unsigned inc;
 288
 289                 inc = ifr->ifr_addr.sa_len;
 290
 291                 if (ioctl(fd, SIOCGIFADDR, ifr) != 0) {
 292                         goto next;
 293                 }
 294
 295                 ipaddr = (*(struct sockaddr_in *) &ifr->ifr_addr).sin_addr;
 296                 iname = ifr->ifr_name;
 297
 298                 if (ioctl(fd, SIOCGIFFLAGS, ifr) != 0) {
 299                         goto next;
 300                 }
 301
 302                 if (!(ifr->ifr_flags & IFF_UP)) {
 303                         goto next;
 304                 }
 305
 306                 if (ioctl(fd, SIOCGIFNETMASK, ifr) != 0) {
 307                         goto next;
 308                 }
 309
 310                 nmask = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
 311
 312                 strncpy(ifaces[total].name, iname, sizeof(ifaces[total].name)-1);
 313                 ifaces[total].name[sizeof(ifaces[total].name)-1] = 0;
 314                 ifaces[total].ip = ipaddr;
 315                 ifaces[total].netmask = nmask;
 316
 317                 total++;
 318
 319         next:
 320                 /*
 321                  * Patch from Archie Cobbs (archie@whistle.com).  The
 322                  * addresses in the SIOCGIFCONF interface list have a
 323                  * minimum size. Usually this doesn't matter, but if
 324                  * your machine has tunnel interfaces, etc. that have
 325                  * a zero length "link address", this does matter.  */
 326
 327                 if (inc < sizeof(ifr->ifr_addr))
 328                         inc = sizeof(ifr->ifr_addr);
 329                 inc += IFNAMSIZ;
 330
 331                 ifr = (struct ifreq*) (((char*) ifr) + inc);
 332                 i -= inc;
 333         }
 334
 335
 336         close(fd);
 337         return total;
 338 }
 339
 340 #else /* a dummy version */
 341 static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
 342 {
 343         return -1;
 344 }
 345 #endif
 346
 347
 348 static int iface_comp(struct iface_struct *i1, struct iface_struct *i2)
 349 {
 350         int r;
 351         r = strcmp(i1->name, i2->name);
 352         if (r) return r;
 353         r = ntohl(i1->ip.s_addr) - ntohl(i2->ip.s_addr);
 354         if (r) return r;
 355         r = ntohl(i1->netmask.s_addr) - ntohl(i2->netmask.s_addr);
 356         return r;
 357 }
 358
 359 /* this wrapper is used to remove duplicates from the interface list generated
 360    above */
 361 int get_interfaces(struct iface_struct *ifaces, int max_interfaces)
 362 {
 363         int total, i, j;
 364
 365         total = _get_interfaces(ifaces, max_interfaces);
 366         if (total <= 0) return total;
 367
 368         /* now we need to remove duplicates */
 369         qsort(ifaces, total, sizeof(ifaces[0]), QSORT_CAST iface_comp);
 370
 371         for (i=1;i<total;) {
 372                 if (iface_comp(&ifaces[i-1], &ifaces[i]) == 0) {
 373                         for (j=i-1;j<total-1;j++) {
 374                                 ifaces[j] = ifaces[j+1];
 375                         }
 376                         total--;
 377                 } else {
 378                         i++;
 379                 }
 380         }
 381
 382         return total;
 383 }
 384
 385
 386 #ifdef AUTOCONF_TEST
 387 /* this is the autoconf driver to test get_interfaces() */
 388
 389 #define MAX_INTERFACES 128
 390
 391  int main()
 392 {
 393         struct iface_struct ifaces[MAX_INTERFACES];
 394         int total = get_interfaces(ifaces, MAX_INTERFACES);
 395         int i;
 396
 397         printf("got %d interfaces:\n", total);
 398         if (total <= 0) exit(1);
 399
 400         for (i=0;i<total;i++) {
 401                 printf("%-10s ", ifaces[i].name);
 402                 printf("IP=%s ", inet_ntoa(ifaces[i].ip));
 403                 printf("NETMASK=%s\n", inet_ntoa(ifaces[i].netmask));
 404         }
 405         return 0;
 406 }
 407 #endif