lib/socket/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    Copyright (C) Jelmer Vernooij 2007
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22
  23 #include "includes.h"
  24 #include "system/network.h"
  25 #include "interfaces.h"
  26 #include "lib/util/tsort.h"
  27
  28 /****************************************************************************
  29  Create a struct sockaddr_storage with the netmask bits set to 1.
  30 ****************************************************************************/
  31
  32 bool make_netmask(struct sockaddr_storage *pss_out,
  33                         const struct sockaddr_storage *pss_in,
  34                         unsigned long masklen)
  35 {
  36         *pss_out = *pss_in;
  37         /* Now apply masklen bits of mask. */
  38 #if defined(HAVE_IPV6)
  39         if (pss_in->ss_family == AF_INET6) {
  40                 char *p = (char *)&((struct sockaddr_in6 *)pss_out)->sin6_addr;
  41                 unsigned int i;
  42
  43                 if (masklen > 128) {
  44                         return false;
  45                 }
  46                 for (i = 0; masklen >= 8; masklen -= 8, i++) {
  47                         *p++ = 0xff;
  48                 }
  49                 /* Deal with the partial byte. */
  50                 *p++ &= (0xff & ~(0xff>>masklen));
  51                 i++;
  52                 for (;i < sizeof(struct in6_addr); i++) {
  53                         *p++ = '\0';
  54                 }
  55                 return true;
  56         }
  57 #endif
  58         if (pss_in->ss_family == AF_INET) {
  59                 if (masklen > 32) {
  60                         return false;
  61                 }
  62                 ((struct sockaddr_in *)pss_out)->sin_addr.s_addr =
  63                         htonl(((0xFFFFFFFFL >> masklen) ^ 0xFFFFFFFFL));
  64                 return true;
  65         }
  66         return false;
  67 }
  68
  69 /****************************************************************************
  70  Create a struct sockaddr_storage set to the broadcast or network adress from
  71  an incoming sockaddr_storage.
  72 ****************************************************************************/
  73
  74 static void make_bcast_or_net(struct sockaddr_storage *pss_out,
  75                         const struct sockaddr_storage *pss_in,
  76                         const struct sockaddr_storage *nmask,
  77                         bool make_bcast_p)
  78 {
  79         unsigned int i = 0, len = 0;
  80         const char *pmask = NULL;
  81         char *p = NULL;
  82         *pss_out = *pss_in;
  83
  84         /* Set all zero netmask bits to 1. */
  85 #if defined(HAVE_IPV6)
  86         if (pss_in->ss_family == AF_INET6) {
  87                 p = (char *)&((struct sockaddr_in6 *)pss_out)->sin6_addr;
  88                 pmask = (const char *)&((const struct sockaddr_in6 *)nmask)->sin6_addr;
  89                 len = 16;
  90         }
  91 #endif
  92         if (pss_in->ss_family == AF_INET) {
  93                 p = (char *)&((struct sockaddr_in *)pss_out)->sin_addr;
  94                 pmask = (const char *)&((const struct sockaddr_in *)nmask)->sin_addr;
  95                 len = 4;
  96         }
  97
  98         for (i = 0; i < len; i++, p++, pmask++) {
  99                 if (make_bcast_p) {
 100                         *p = (*p & *pmask) | (*pmask ^ 0xff);
 101                 } else {
 102                         /* make_net */
 103                         *p = (*p & *pmask);
 104                 }
 105         }
 106 }
 107
 108 void make_bcast(struct sockaddr_storage *pss_out,
 109                         const struct sockaddr_storage *pss_in,
 110                         const struct sockaddr_storage *nmask)
 111 {
 112         make_bcast_or_net(pss_out, pss_in, nmask, true);
 113 }
 114
 115 void make_net(struct sockaddr_storage *pss_out,
 116                         const struct sockaddr_storage *pss_in,
 117                         const struct sockaddr_storage *nmask)
 118 {
 119         make_bcast_or_net(pss_out, pss_in, nmask, false);
 120 }
 121
 122
 123 /****************************************************************************
 124  Try the "standard" getifaddrs/freeifaddrs interfaces.
 125  Also gets IPv6 interfaces.
 126 ****************************************************************************/
 127
 128 /****************************************************************************
 129  Get the netmask address for a local interface.
 130 ****************************************************************************/
 131
 132 static int _get_interfaces(TALLOC_CTX *mem_ctx, struct iface_struct **pifaces)
 133 {
 134         struct iface_struct *ifaces;
 135         struct ifaddrs *iflist = NULL;
 136         struct ifaddrs *ifptr = NULL;
 137         int count;
 138         int total = 0;
 139         size_t copy_size;
 140
 141         if (getifaddrs(&iflist) < 0) {
 142                 return -1;
 143         }
 144
 145         count = 0;
 146         for (ifptr = iflist; ifptr != NULL; ifptr = ifptr->ifa_next) {
 147                 if (!ifptr->ifa_addr || !ifptr->ifa_netmask) {
 148                         continue;
 149                 }
 150                 if (!(ifptr->ifa_flags & IFF_UP)) {
 151                         continue;
 152                 }
 153                 count += 1;
 154         }
 155
 156         ifaces = talloc_array(mem_ctx, struct iface_struct, count);
 157         if (ifaces == NULL) {
 158                 errno = ENOMEM;
 159                 return -1;
 160         }
 161
 162         /* Loop through interfaces, looking for given IP address */
 163         for (ifptr = iflist; ifptr != NULL; ifptr = ifptr->ifa_next) {
 164
 165                 if (!ifptr->ifa_addr || !ifptr->ifa_netmask) {
 166                         continue;
 167                 }
 168
 169                 /* Check the interface is up. */
 170                 if (!(ifptr->ifa_flags & IFF_UP)) {
 171                         continue;
 172                 }
 173
 174                 memset(&ifaces[total], '\0', sizeof(ifaces[total]));
 175
 176                 copy_size = sizeof(struct sockaddr_in);
 177
 178                 ifaces[total].flags = ifptr->ifa_flags;
 179
 180 #if defined(HAVE_IPV6)
 181                 if (ifptr->ifa_addr->sa_family == AF_INET6) {
 182                         copy_size = sizeof(struct sockaddr_in6);
 183                 }
 184 #endif
 185
 186                 memcpy(&ifaces[total].ip, ifptr->ifa_addr, copy_size);
 187                 memcpy(&ifaces[total].netmask, ifptr->ifa_netmask, copy_size);
 188
 189                 if (ifaces[total].flags & (IFF_BROADCAST|IFF_LOOPBACK)) {
 190                         make_bcast(&ifaces[total].bcast,
 191                                 &ifaces[total].ip,
 192                                 &ifaces[total].netmask);
 193                 } else if ((ifaces[total].flags & IFF_POINTOPOINT) &&
 194                                ifptr->ifa_dstaddr ) {
 195                         memcpy(&ifaces[total].bcast,
 196                                 ifptr->ifa_dstaddr,
 197                                 copy_size);
 198 #if defined(HAVE_IPV6)
 199                 } else if (ifptr->ifa_addr->sa_family == AF_INET6) {
 200                         const struct sockaddr_in6 *sin6 =
 201                                 (const struct sockaddr_in6 *)ifptr->ifa_addr;
 202                         const struct in6_addr *in6 =
 203                                 (const struct in6_addr *)&sin6->sin6_addr;
 204
 205                         if (IN6_IS_ADDR_LINKLOCAL(in6) || IN6_IS_ADDR_V4COMPAT(in6)) {
 206                                 continue;
 207                         }
 208                         /* IPv6 does not have broadcast it uses multicast. */
 209                         memset(&ifaces[total].bcast, '\0', copy_size);
 210 #endif
 211                 } else {
 212                         continue;
 213                 }
 214
 215                 if (strlcpy(ifaces[total].name, ifptr->ifa_name,
 216                         sizeof(ifaces[total].name)) >=
 217                                 sizeof(ifaces[total].name)) {
 218                         /* Truncation ! Ignore. */
 219                         continue;
 220                 }
 221                 total++;
 222         }
 223
 224         freeifaddrs(iflist);
 225
 226         *pifaces = ifaces;
 227         return total;
 228 }
 229
 230 static int iface_comp(struct iface_struct *i1, struct iface_struct *i2)
 231 {
 232         int r;
 233
 234 #if defined(HAVE_IPV6)
 235         /*
 236          * If we have IPv6 - sort these interfaces lower
 237          * than any IPv4 ones.
 238          */
 239         if (i1->ip.ss_family == AF_INET6 &&
 240                         i2->ip.ss_family == AF_INET) {
 241                 return -1;
 242         } else if (i1->ip.ss_family == AF_INET &&
 243                         i2->ip.ss_family == AF_INET6) {
 244                 return 1;
 245         }
 246
 247         if (i1->ip.ss_family == AF_INET6) {
 248                 struct sockaddr_in6 *s1 = (struct sockaddr_in6 *)&i1->ip;
 249                 struct sockaddr_in6 *s2 = (struct sockaddr_in6 *)&i2->ip;
 250
 251                 r = memcmp(&s1->sin6_addr,
 252                                 &s2->sin6_addr,
 253                                 sizeof(struct in6_addr));
 254                 if (r) {
 255                         return r;
 256                 }
 257
 258                 s1 = (struct sockaddr_in6 *)&i1->netmask;
 259                 s2 = (struct sockaddr_in6 *)&i2->netmask;
 260
 261                 r = memcmp(&s1->sin6_addr,
 262                                 &s2->sin6_addr,
 263                                 sizeof(struct in6_addr));
 264                 if (r) {
 265                         return r;
 266                 }
 267         }
 268 #endif
 269
 270         /* AIX uses __ss_family instead of ss_family inside of
 271            sockaddr_storage. Instead of trying to figure out which field to
 272            use, we can just cast it to a sockaddr.
 273          */
 274
 275         if (((struct sockaddr *)&i1->ip)->sa_family == AF_INET) {
 276                 struct sockaddr_in *s1 = (struct sockaddr_in *)&i1->ip;
 277                 struct sockaddr_in *s2 = (struct sockaddr_in *)&i2->ip;
 278
 279                 r = ntohl(s1->sin_addr.s_addr) -
 280                         ntohl(s2->sin_addr.s_addr);
 281                 if (r) {
 282                         return r;
 283                 }
 284
 285                 s1 = (struct sockaddr_in *)&i1->netmask;
 286                 s2 = (struct sockaddr_in *)&i2->netmask;
 287
 288                 return ntohl(s1->sin_addr.s_addr) -
 289                         ntohl(s2->sin_addr.s_addr);
 290         }
 291         return 0;
 292 }
 293
 294 /* this wrapper is used to remove duplicates from the interface list generated
 295    above */
 296 int get_interfaces(TALLOC_CTX *mem_ctx, struct iface_struct **pifaces)
 297 {
 298         struct iface_struct *ifaces;
 299         int total, i, j;
 300
 301         total = _get_interfaces(mem_ctx, &ifaces);
 302         if (total <= 0) return total;
 303
 304         /* now we need to remove duplicates */
 305         TYPESAFE_QSORT(ifaces, total, iface_comp);
 306
 307         for (i=1;i<total;) {
 308                 if (iface_comp(&ifaces[i-1], &ifaces[i]) == 0) {
 309                         for (j=i-1;j<total-1;j++) {
 310                                 ifaces[j] = ifaces[j+1];
 311                         }
 312                         total--;
 313                 } else {
 314                         i++;
 315                 }
 316         }
 317
 318         *pifaces = ifaces;
 319         return total;
 320 }