contrib/bind9/lib/isc/unix/ifiter_getifaddrs.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007-2009  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: ifiter_getifaddrs.c,v 1.13 2009/09/24 23:48:13 tbox Exp $ */
  19
  20 /*! \file
  21  * \brief
  22  * Obtain the list of network interfaces using the getifaddrs(3) library.
  23  */
  24
  25 #include <ifaddrs.h>
  26
  27 /*% Iterator Magic */
  28 #define IFITER_MAGIC            ISC_MAGIC('I', 'F', 'I', 'G')
  29 /*% Valid Iterator */
  30 #define VALID_IFITER(t)         ISC_MAGIC_VALID(t, IFITER_MAGIC)
  31
  32 #ifdef __linux
  33 static isc_boolean_t seenv6 = ISC_FALSE;
  34 #endif
  35
  36 /*% Iterator structure */
  37 struct isc_interfaceiter {
  38         unsigned int            magic;          /*%< Magic number. */
  39         isc_mem_t               *mctx;
  40         void                    *buf;           /*%< (unused) */
  41         unsigned int            bufsize;        /*%< (always 0) */
  42         struct ifaddrs          *ifaddrs;       /*%< List of ifaddrs */
  43         struct ifaddrs          *pos;           /*%< Ptr to current ifaddr */
  44         isc_interface_t         current;        /*%< Current interface data. */
  45         isc_result_t            result;         /*%< Last result code. */
  46 #ifdef  __linux
  47         FILE *                  proc;
  48         char                    entry[ISC_IF_INET6_SZ];
  49         isc_result_t            valid;
  50 #endif
  51 };
  52
  53 isc_result_t
  54 isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
  55         isc_interfaceiter_t *iter;
  56         isc_result_t result;
  57         char strbuf[ISC_STRERRORSIZE];
  58
  59         REQUIRE(mctx != NULL);
  60         REQUIRE(iterp != NULL);
  61         REQUIRE(*iterp == NULL);
  62
  63         iter = isc_mem_get(mctx, sizeof(*iter));
  64         if (iter == NULL)
  65                 return (ISC_R_NOMEMORY);
  66
  67         iter->mctx = mctx;
  68         iter->buf = NULL;
  69         iter->bufsize = 0;
  70         iter->ifaddrs = NULL;
  71 #ifdef __linux
  72         /*
  73          * Only open "/proc/net/if_inet6" if we have never seen a IPv6
  74          * address returned by getifaddrs().
  75          */
  76         if (!seenv6)
  77                 iter->proc = fopen("/proc/net/if_inet6", "r");
  78         else
  79                 iter->proc = NULL;
  80         iter->valid = ISC_R_FAILURE;
  81 #endif
  82
  83         if (getifaddrs(&iter->ifaddrs) < 0) {
  84                 isc__strerror(errno, strbuf, sizeof(strbuf));
  85                 UNEXPECTED_ERROR(__FILE__, __LINE__,
  86                                  isc_msgcat_get(isc_msgcat,
  87                                                 ISC_MSGSET_IFITERGETIFADDRS,
  88                                                 ISC_MSG_GETIFADDRS,
  89                                                 "getting interface "
  90                                                 "addresses: getifaddrs: %s"),
  91                                  strbuf);
  92                 result = ISC_R_UNEXPECTED;
  93                 goto failure;
  94         }
  95
  96         /*
  97          * A newly created iterator has an undefined position
  98          * until isc_interfaceiter_first() is called.
  99          */
 100         iter->pos = NULL;
 101         iter->result = ISC_R_FAILURE;
 102
 103         iter->magic = IFITER_MAGIC;
 104         *iterp = iter;
 105         return (ISC_R_SUCCESS);
 106
 107  failure:
 108 #ifdef __linux
 109         if (iter->proc != NULL)
 110                 fclose(iter->proc);
 111 #endif
 112         if (iter->ifaddrs != NULL) /* just in case */
 113                 freeifaddrs(iter->ifaddrs);
 114         isc_mem_put(mctx, iter, sizeof(*iter));
 115         return (result);
 116 }
 117
 118 /*
 119  * Get information about the current interface to iter->current.
 120  * If successful, return ISC_R_SUCCESS.
 121  * If the interface has an unsupported address family,
 122  * return ISC_R_IGNORE.
 123  */
 124
 125 static isc_result_t
 126 internal_current(isc_interfaceiter_t *iter) {
 127         struct ifaddrs *ifa;
 128         int family;
 129         unsigned int namelen;
 130
 131         REQUIRE(VALID_IFITER(iter));
 132
 133         ifa = iter->pos;
 134
 135 #ifdef __linux
 136         if (iter->pos == NULL)
 137                 return (linux_if_inet6_current(iter));
 138 #endif
 139
 140         INSIST(ifa != NULL);
 141         INSIST(ifa->ifa_name != NULL);
 142
 143         if (ifa->ifa_addr == NULL)
 144                 return (ISC_R_IGNORE);
 145
 146         family = ifa->ifa_addr->sa_family;
 147         if (family != AF_INET && family != AF_INET6)
 148                 return (ISC_R_IGNORE);
 149
 150 #ifdef __linux
 151         if (family == AF_INET6)
 152                 seenv6 = ISC_TRUE;
 153 #endif
 154
 155         memset(&iter->current, 0, sizeof(iter->current));
 156
 157         namelen = strlen(ifa->ifa_name);
 158         if (namelen > sizeof(iter->current.name) - 1)
 159                 namelen = sizeof(iter->current.name) - 1;
 160
 161         memset(iter->current.name, 0, sizeof(iter->current.name));
 162         memcpy(iter->current.name, ifa->ifa_name, namelen);
 163
 164         iter->current.flags = 0;
 165
 166         if ((ifa->ifa_flags & IFF_UP) != 0)
 167                 iter->current.flags |= INTERFACE_F_UP;
 168
 169         if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0)
 170                 iter->current.flags |= INTERFACE_F_POINTTOPOINT;
 171
 172         if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)
 173                 iter->current.flags |= INTERFACE_F_LOOPBACK;
 174
 175         iter->current.af = family;
 176
 177         get_addr(family, &iter->current.address, ifa->ifa_addr, ifa->ifa_name);
 178
 179         if (ifa->ifa_netmask != NULL)
 180                 get_addr(family, &iter->current.netmask, ifa->ifa_netmask,
 181                          ifa->ifa_name);
 182
 183         if (ifa->ifa_dstaddr != NULL &&
 184             (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
 185                 get_addr(family, &iter->current.dstaddress, ifa->ifa_dstaddr,
 186                          ifa->ifa_name);
 187
 188         return (ISC_R_SUCCESS);
 189 }
 190
 191 /*
 192  * Step the iterator to the next interface.  Unlike
 193  * isc_interfaceiter_next(), this may leave the iterator
 194  * positioned on an interface that will ultimately
 195  * be ignored.  Return ISC_R_NOMORE if there are no more
 196  * interfaces, otherwise ISC_R_SUCCESS.
 197  */
 198 static isc_result_t
 199 internal_next(isc_interfaceiter_t *iter) {
 200
 201         if (iter->pos != NULL)
 202                 iter->pos = iter->pos->ifa_next;
 203         if (iter->pos == NULL) {
 204 #ifdef __linux
 205                 if (!seenv6)
 206                         return (linux_if_inet6_next(iter));
 207 #endif
 208                 return (ISC_R_NOMORE);
 209         }
 210
 211         return (ISC_R_SUCCESS);
 212 }
 213
 214 static void
 215 internal_destroy(isc_interfaceiter_t *iter) {
 216
 217 #ifdef __linux
 218         if (iter->proc != NULL)
 219                 fclose(iter->proc);
 220         iter->proc = NULL;
 221 #endif
 222         if (iter->ifaddrs)
 223                 freeifaddrs(iter->ifaddrs);
 224         iter->ifaddrs = NULL;
 225 }
 226
 227 static
 228 void internal_first(isc_interfaceiter_t *iter) {
 229
 230 #ifdef __linux
 231         linux_if_inet6_first(iter);
 232 #endif
 233         iter->pos = iter->ifaddrs;
 234 }