source3/lib/interfaces.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    return a list of network interfaces
   4    Copyright (C) Andrew Tridgell 1998
   5    Copyright (C) Jeremy Allison 2007
   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 3 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, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "interfaces.h"
  23
  24 /****************************************************************************
  25  Create a struct sockaddr_storage with the netmask bits set to 1.
  26 ****************************************************************************/
  27
  28 bool make_netmask(struct sockaddr_storage *pss_out,
  29                         const struct sockaddr_storage *pss_in,
  30                         unsigned long masklen)
  31 {
  32         *pss_out = *pss_in;
  33         /* Now apply masklen bits of mask. */
  34 #if defined(HAVE_IPV6)
  35         if (pss_in->ss_family == AF_INET6) {
  36                 char *p = (char *)&((struct sockaddr_in6 *)pss_out)->sin6_addr;
  37                 unsigned int i;
  38
  39                 if (masklen > 128) {
  40                         return false;
  41                 }
  42                 for (i = 0; masklen >= 8; masklen -= 8, i++) {
  43                         *p++ = 0xff;
  44                 }
  45                 /* Deal with the partial byte. */
  46                 *p++ &= (0xff & ~(0xff>>masklen));
  47                 i++;
  48                 for (;i < sizeof(struct in6_addr); i++) {
  49                         *p++ = '\0';
  50                 }
  51                 return true;
  52         }
  53 #endif
  54         if (pss_in->ss_family == AF_INET) {
  55                 if (masklen > 32) {
  56                         return false;
  57                 }
  58                 ((struct sockaddr_in *)pss_out)->sin_addr.s_addr =
  59                         htonl(((0xFFFFFFFFL >> masklen) ^ 0xFFFFFFFFL));
  60                 return true;
  61         }
  62         return false;
  63 }
  64
  65 /****************************************************************************
  66  Create a struct sockaddr_storage set to the broadcast or network adress from
  67  an incoming sockaddr_storage.
  68 ****************************************************************************/
  69
  70 static void make_bcast_or_net(struct sockaddr_storage *pss_out,
  71                         const struct sockaddr_storage *pss_in,
  72                         const struct sockaddr_storage *nmask,
  73                         bool make_bcast_p)
  74 {
  75         unsigned int i = 0, len = 0;
  76         char *pmask = NULL;
  77         char *p = NULL;
  78         *pss_out = *pss_in;
  79
  80         /* Set all zero netmask bits to 1. */
  81 #if defined(HAVE_IPV6)
  82         if (pss_in->ss_family == AF_INET6) {
  83                 p = (char *)&((struct sockaddr_in6 *)pss_out)->sin6_addr;
  84                 pmask = (char *)&((struct sockaddr_in6 *)nmask)->sin6_addr;
  85                 len = 16;
  86         }
  87 #endif
  88         if (pss_in->ss_family == AF_INET) {
  89                 p = (char *)&((struct sockaddr_in *)pss_out)->sin_addr;
  90                 pmask = (char *)&((struct sockaddr_in *)nmask)->sin_addr;
  91                 len = 4;
  92         }
  93
  94         for (i = 0; i < len; i++, p++, pmask++) {
  95                 if (make_bcast_p) {
  96                         *p = (*p & *pmask) | (*pmask ^ 0xff);
  97                 } else {
  98                         /* make_net */
  99                         *p = (*p & *pmask);
 100                 }
 101         }
 102 }
 103
 104 void make_bcast(struct sockaddr_storage *pss_out,
 105                         const struct sockaddr_storage *pss_in,
 106                         const struct sockaddr_storage *nmask)
 107 {
 108         make_bcast_or_net(pss_out, pss_in, nmask, true);
 109 }
 110
 111 void make_net(struct sockaddr_storage *pss_out,
 112                         const struct sockaddr_storage *pss_in,
 113                         const struct sockaddr_storage *nmask)
 114 {
 115         make_bcast_or_net(pss_out, pss_in, nmask, false);
 116 }
 117
 118 /****************************************************************************
 119  Try the "standard" getifaddrs/freeifaddrs interfaces.
 120  Also gets IPv6 interfaces.
 121 ****************************************************************************/
 122
 123 /****************************************************************************
 124  Get the netmask address for a local interface.
 125 ****************************************************************************/
 126
 127 static int _get_interfaces(TALLOC_CTX *mem_ctx, struct iface_struct **pifaces)
 128 {
 129         struct iface_struct *ifaces;
 130         struct ifaddrs *iflist = NULL;
 131         struct ifaddrs *ifptr = NULL;
 132         int count;
 133         int total = 0;
 134         size_t copy_size;
 135
 136         if (getifaddrs(&iflist) < 0) {
 137                 return -1;
 138         }
 139
 140         count = 0;
 141         for (ifptr = iflist; ifptr != NULL; ifptr = ifptr->ifa_next) {
 142                 if (!ifptr->ifa_addr || !ifptr->ifa_netmask) {
 143                         continue;
 144                 }
 145                 if (!(ifptr->ifa_flags & IFF_UP)) {
 146                         continue;
 147                 }
 148                 count += 1;
 149         }
 150
 151         ifaces = talloc_array(mem_ctx, struct iface_struct, count);
 152         if (ifaces == NULL) {
 153                 errno = ENOMEM;
 154                 return -1;
 155         }
 156
 157         /* Loop through interfaces, looking for given IP address */
 158         for (ifptr = iflist; ifptr != NULL; ifptr = ifptr->ifa_next) {
 159
 160                 if (!ifptr->ifa_addr || !ifptr->ifa_netmask) {
 161                         continue;
 162                 }
 163
 164                 /* Check the interface is up. */
 165                 if (!(ifptr->ifa_flags & IFF_UP)) {
 166                         continue;
 167                 }
 168
 169                 memset(&ifaces[total], '\0', sizeof(ifaces[total]));
 170
 171                 copy_size = sizeof(struct sockaddr_in);
 172
 173                 ifaces[total].flags = ifptr->ifa_flags;
 174
 175 #if defined(HAVE_IPV6)
 176                 if (ifptr->ifa_addr->sa_family == AF_INET6) {
 177                         copy_size = sizeof(struct sockaddr_in6);
 178                 }
 179 #endif
 180
 181                 memcpy(&ifaces[total].ip, ifptr->ifa_addr, copy_size);
 182                 memcpy(&ifaces[total].netmask, ifptr->ifa_netmask, copy_size);
 183
 184                 if (ifaces[total].flags & (IFF_BROADCAST|IFF_LOOPBACK)) {
 185                         make_bcast(&ifaces[total].bcast,
 186                                 &ifaces[total].ip,
 187                                 &ifaces[total].netmask);
 188                 } else if ((ifaces[total].flags & IFF_POINTOPOINT) &&
 189                                ifptr->ifa_dstaddr ) {
 190                         memcpy(&ifaces[total].bcast,
 191                                 ifptr->ifa_dstaddr,
 192                                 copy_size);
 193                 } else {
 194                         continue;
 195                 }
 196
 197                 strlcpy(ifaces[total].name, ifptr->ifa_name,
 198                         sizeof(ifaces[total].name));
 199                 total++;
 200         }
 201
 202         freeifaddrs(iflist);
 203
 204         *pifaces = ifaces;
 205         return total;
 206 }
 207
 208 static int iface_comp(struct iface_struct *i1, struct iface_struct *i2)
 209 {
 210         int r;
 211
 212 #if defined(HAVE_IPV6)
 213         /*
 214          * If we have IPv6 - sort these interfaces lower
 215          * than any IPv4 ones.
 216          */
 217         if (i1->ip.ss_family == AF_INET6 &&
 218                         i2->ip.ss_family == AF_INET) {
 219                 return -1;
 220         } else if (i1->ip.ss_family == AF_INET &&
 221                         i2->ip.ss_family == AF_INET6) {
 222                 return 1;
 223         }
 224
 225         if (i1->ip.ss_family == AF_INET6) {
 226                 struct sockaddr_in6 *s1 = (struct sockaddr_in6 *)&i1->ip;
 227                 struct sockaddr_in6 *s2 = (struct sockaddr_in6 *)&i2->ip;
 228
 229                 r = memcmp(&s1->sin6_addr,
 230                                 &s2->sin6_addr,
 231                                 sizeof(struct in6_addr));
 232                 if (r) {
 233                         return r;
 234                 }
 235
 236                 s1 = (struct sockaddr_in6 *)&i1->netmask;
 237                 s2 = (struct sockaddr_in6 *)&i2->netmask;
 238
 239                 r = memcmp(&s1->sin6_addr,
 240                                 &s2->sin6_addr,
 241                                 sizeof(struct in6_addr));
 242                 if (r) {
 243                         return r;
 244                 }
 245         }
 246 #endif
 247
 248         /* AIX uses __ss_family instead of ss_family inside of
 249            sockaddr_storage. Instead of trying to figure out which field to
 250            use, we can just cast it to a sockaddr.
 251          */
 252
 253         if (((struct sockaddr *)&i1->ip)->sa_family == AF_INET) {
 254                 struct sockaddr_in *s1 = (struct sockaddr_in *)&i1->ip;
 255                 struct sockaddr_in *s2 = (struct sockaddr_in *)&i2->ip;
 256
 257                 r = ntohl(s1->sin_addr.s_addr) -
 258                         ntohl(s2->sin_addr.s_addr);
 259                 if (r) {
 260                         return r;
 261                 }
 262
 263                 s1 = (struct sockaddr_in *)&i1->netmask;
 264                 s2 = (struct sockaddr_in *)&i2->netmask;
 265
 266                 return ntohl(s1->sin_addr.s_addr) -
 267                         ntohl(s2->sin_addr.s_addr);
 268         }
 269         return 0;
 270 }
 271
 272 /* this wrapper is used to remove duplicates from the interface list generated
 273    above */
 274 int get_interfaces(TALLOC_CTX *mem_ctx, struct iface_struct **pifaces)
 275 {
 276         struct iface_struct *ifaces;
 277         int total, i, j;
 278
 279         total = _get_interfaces(mem_ctx, &ifaces);
 280         if (total <= 0) return total;
 281
 282         /* now we need to remove duplicates */
 283         TYPESAFE_QSORT(ifaces, total, iface_comp);
 284
 285         for (i=1;i<total;) {
 286                 if (iface_comp(&ifaces[i-1], &ifaces[i]) == 0) {
 287                         for (j=i-1;j<total-1;j++) {
 288                                 ifaces[j] = ifaces[j+1];
 289                         }
 290                         total--;
 291                 } else {
 292                         i++;
 293                 }
 294         }
 295
 296         *pifaces = ifaces;
 297         return total;
 298 }
 299