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