contrib/ntp/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         int trys, ret;
  59
  60         REQUIRE(mctx != NULL);
  61         REQUIRE(iterp != NULL);
  62         REQUIRE(*iterp == NULL);
  63
  64         iter = isc_mem_get(mctx, sizeof(*iter));
  65         if (iter == NULL)
  66                 return (ISC_R_NOMEMORY);
  67
  68         iter->mctx = mctx;
  69         iter->buf = NULL;
  70         iter->bufsize = 0;
  71         iter->ifaddrs = NULL;
  72 #ifdef __linux
  73         /*
  74          * Only open "/proc/net/if_inet6" if we have never seen a IPv6
  75          * address returned by getifaddrs().
  76          */
  77         if (!seenv6) {
  78                 iter->proc = fopen("/proc/net/if_inet6", "r");
  79                 if (iter->proc == NULL) {
  80                         isc__strerror(errno, strbuf, sizeof(strbuf));
  81                         isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  82                                       ISC_LOGMODULE_SOCKET, ISC_LOG_WARNING,
  83                                       "failed to open /proc/net/if_inet6");
  84                 }
  85         } else
  86                 iter->proc = NULL;
  87         iter->valid = ISC_R_FAILURE;
  88 #endif
  89
  90         /* If interrupted, try again */
  91         for (trys = 0; trys < 3; trys++) {
  92                 if ((ret = getifaddrs(&iter->ifaddrs)) >= 0)
  93                         break;
  94                 if (errno != EINTR)
  95                         break;
  96         }
  97         if (ret < 0) {
  98                 isc__strerror(errno, strbuf, sizeof(strbuf));
  99                 UNEXPECTED_ERROR(__FILE__, __LINE__,
 100                                  "getting interface addresses: %s: %s",
 101                                  isc_msgcat_get(isc_msgcat,
 102                                                 ISC_MSGSET_IFITERGETIFADDRS,
 103                                                 ISC_MSG_GETIFADDRS,
 104                                                 "getifaddrs"),
 105                                  strbuf);
 106                 result = ISC_R_UNEXPECTED;
 107                 goto failure;
 108         }
 109
 110         /*
 111          * A newly created iterator has an undefined position
 112          * until isc_interfaceiter_first() is called.
 113          */
 114         iter->pos = NULL;
 115         iter->result = ISC_R_FAILURE;
 116
 117         iter->magic = IFITER_MAGIC;
 118         *iterp = iter;
 119         return (ISC_R_SUCCESS);
 120
 121  failure:
 122 #ifdef __linux
 123         if (iter->proc != NULL)
 124                 fclose(iter->proc);
 125 #endif
 126         if (iter->ifaddrs != NULL) /* just in case */
 127                 freeifaddrs(iter->ifaddrs);
 128         isc_mem_put(mctx, iter, sizeof(*iter));
 129         return (result);
 130 }
 131
 132 /*
 133  * Get information about the current interface to iter->current.
 134  * If successful, return ISC_R_SUCCESS.
 135  * If the interface has an unsupported address family,
 136  * return ISC_R_IGNORE.
 137  */
 138
 139 static isc_result_t
 140 internal_current(isc_interfaceiter_t *iter) {
 141         struct ifaddrs *ifa;
 142         int family;
 143         unsigned int namelen;
 144
 145         REQUIRE(VALID_IFITER(iter));
 146
 147         ifa = iter->pos;
 148
 149 #ifdef __linux
 150         /*
 151          * [Bug 2792]
 152          * burnicki: iter->pos is usually never NULL here (anymore?),
 153          * so linux_if_inet6_current(iter) is never called here.
 154          * However, that routine would check (under Linux), if the
 155          * interface is in a tentative state, e.g. if there's no link
 156          * yet but an IPv6 address has already be assigned.
 157          */
 158         if (iter->pos == NULL)
 159                 return (linux_if_inet6_current(iter));
 160 #endif
 161
 162         INSIST(ifa != NULL);
 163         INSIST(ifa->ifa_name != NULL);
 164
 165
 166 #ifdef IFF_RUNNING
 167         /*
 168          * [Bug 2792]
 169          * burnicki: if the interface is not running then
 170          * it may be in a tentative state. See above.
 171          */
 172         if ((ifa->ifa_flags & IFF_RUNNING) == 0)
 173                 return (ISC_R_IGNORE);
 174 #endif
 175
 176         if (ifa->ifa_addr == NULL)
 177                 return (ISC_R_IGNORE);
 178
 179         family = ifa->ifa_addr->sa_family;
 180         if (family != AF_INET && family != AF_INET6)
 181                 return (ISC_R_IGNORE);
 182
 183 #ifdef __linux
 184         if (family == AF_INET6)
 185                 seenv6 = ISC_TRUE;
 186 #endif
 187
 188         memset(&iter->current, 0, sizeof(iter->current));
 189
 190         namelen = strlen(ifa->ifa_name);
 191         if (namelen > sizeof(iter->current.name) - 1)
 192                 namelen = sizeof(iter->current.name) - 1;
 193
 194         memset(iter->current.name, 0, sizeof(iter->current.name));
 195         memcpy(iter->current.name, ifa->ifa_name, namelen);
 196
 197         iter->current.flags = 0;
 198
 199         if ((ifa->ifa_flags & IFF_UP) != 0)
 200                 iter->current.flags |= INTERFACE_F_UP;
 201
 202         if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0)
 203                 iter->current.flags |= INTERFACE_F_POINTTOPOINT;
 204
 205         if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)
 206                 iter->current.flags |= INTERFACE_F_LOOPBACK;
 207
 208         if ((ifa->ifa_flags & IFF_BROADCAST) != 0)
 209                 iter->current.flags |= INTERFACE_F_BROADCAST;
 210
 211 #ifdef IFF_MULTICAST
 212         if ((ifa->ifa_flags & IFF_MULTICAST) != 0)
 213                 iter->current.flags |= INTERFACE_F_MULTICAST;
 214 #endif
 215
 216         iter->current.af = family;
 217
 218         get_addr(family, &iter->current.address, ifa->ifa_addr, ifa->ifa_name);
 219
 220         if (ifa->ifa_netmask != NULL)
 221                 get_addr(family, &iter->current.netmask, ifa->ifa_netmask,
 222                          ifa->ifa_name);
 223
 224         if (ifa->ifa_dstaddr != NULL &&
 225             (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
 226                 get_addr(family, &iter->current.dstaddress, ifa->ifa_dstaddr,
 227                          ifa->ifa_name);
 228
 229         if (ifa->ifa_broadaddr != NULL &&
 230             (iter->current.flags & INTERFACE_F_BROADCAST) != 0)
 231                 get_addr(family, &iter->current.broadcast, ifa->ifa_broadaddr,
 232                          ifa->ifa_name);
 233
 234 #ifdef ISC_PLATFORM_HAVEIFNAMETOINDEX
 235         iter->current.ifindex = if_nametoindex(iter->current.name);
 236 #endif
 237         return (ISC_R_SUCCESS);
 238 }
 239
 240 /*
 241  * Step the iterator to the next interface.  Unlike
 242  * isc_interfaceiter_next(), this may leave the iterator
 243  * positioned on an interface that will ultimately
 244  * be ignored.  Return ISC_R_NOMORE if there are no more
 245  * interfaces, otherwise ISC_R_SUCCESS.
 246  */
 247 static isc_result_t
 248 internal_next(isc_interfaceiter_t *iter) {
 249
 250         if (iter->pos != NULL)
 251                 iter->pos = iter->pos->ifa_next;
 252         if (iter->pos == NULL) {
 253 #ifdef __linux
 254                 if (!seenv6)
 255                         return (linux_if_inet6_next(iter));
 256 #endif
 257                 return (ISC_R_NOMORE);
 258         }
 259
 260         return (ISC_R_SUCCESS);
 261 }
 262
 263 static void
 264 internal_destroy(isc_interfaceiter_t *iter) {
 265
 266 #ifdef __linux
 267         if (iter->proc != NULL)
 268                 fclose(iter->proc);
 269         iter->proc = NULL;
 270 #endif
 271         if (iter->ifaddrs)
 272                 freeifaddrs(iter->ifaddrs);
 273         iter->ifaddrs = NULL;
 274 }
 275
 276 static
 277 void internal_first(isc_interfaceiter_t *iter) {
 278
 279 #ifdef __linux
 280         linux_if_inet6_first(iter);
 281 #endif
 282         iter->pos = iter->ifaddrs;
 283 }