contrib/bind/lib/isc/unix/ifiter_sysctl.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  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_sysctl.c,v 1.25 2007/06/19 23:47:18 tbox Exp $ */
  19
  20 /*! \file
  21  * \brief
  22  * Obtain the list of network interfaces using sysctl.
  23  * See TCP/IP Illustrated Volume 2, sections 19.8, 19.14,
  24  * and 19.16.
  25  */
  26
  27 #include <sys/param.h>
  28 #include <sys/sysctl.h>
  29
  30 #include <net/route.h>
  31 #include <net/if_dl.h>
  32
  33 /* XXX what about Alpha? */
  34 #ifdef sgi
  35 #define ROUNDUP(a) ((a) > 0 ? \
  36                 (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) : \
  37                 sizeof(__uint64_t))
  38 #else
  39 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
  40                     : sizeof(long))
  41 #endif
  42
  43 #define IFITER_MAGIC            ISC_MAGIC('I', 'F', 'I', 'S')
  44 #define VALID_IFITER(t)         ISC_MAGIC_VALID(t, IFITER_MAGIC)
  45
  46 struct isc_interfaceiter {
  47         unsigned int            magic;          /* Magic number. */
  48         isc_mem_t               *mctx;
  49         void                    *buf;           /* Buffer for sysctl data. */
  50         unsigned int            bufsize;        /* Bytes allocated. */
  51         unsigned int            bufused;        /* Bytes used. */
  52         unsigned int            pos;            /* Current offset in
  53                                                    sysctl data. */
  54         isc_interface_t         current;        /* Current interface data. */
  55         isc_result_t            result;         /* Last result code. */
  56 };
  57
  58 static int mib[6] = {
  59         CTL_NET,
  60         PF_ROUTE,
  61         0,
  62         0,                      /* Any address family. */
  63         NET_RT_IFLIST,
  64         0                       /* Flags. */
  65 };
  66
  67 isc_result_t
  68 isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
  69         isc_interfaceiter_t *iter;
  70         isc_result_t result;
  71         size_t bufsize;
  72         size_t bufused;
  73         char strbuf[ISC_STRERRORSIZE];
  74
  75         REQUIRE(mctx != NULL);
  76         REQUIRE(iterp != NULL);
  77         REQUIRE(*iterp == NULL);
  78
  79         iter = isc_mem_get(mctx, sizeof(*iter));
  80         if (iter == NULL)
  81                 return (ISC_R_NOMEMORY);
  82
  83         iter->mctx = mctx;
  84         iter->buf = 0;
  85
  86         /*
  87          * Determine the amount of memory needed.
  88          */
  89         bufsize = 0;
  90         if (sysctl(mib, 6, NULL, &bufsize, NULL, (size_t) 0) < 0) {
  91                 isc__strerror(errno, strbuf, sizeof(strbuf));
  92                 UNEXPECTED_ERROR(__FILE__, __LINE__,
  93                                  isc_msgcat_get(isc_msgcat,
  94                                                 ISC_MSGSET_IFITERSYSCTL,
  95                                                 ISC_MSG_GETIFLISTSIZE,
  96                                                 "getting interface "
  97                                                 "list size: sysctl: %s"),
  98                                  strbuf);
  99                 result = ISC_R_UNEXPECTED;
 100                 goto failure;
 101         }
 102         iter->bufsize = bufsize;
 103
 104         iter->buf = isc_mem_get(iter->mctx, iter->bufsize);
 105         if (iter->buf == NULL) {
 106                 result = ISC_R_NOMEMORY;
 107                 goto failure;
 108         }
 109
 110         bufused = bufsize;
 111         if (sysctl(mib, 6, iter->buf, &bufused, NULL, (size_t) 0) < 0) {
 112                 isc__strerror(errno, strbuf, sizeof(strbuf));
 113                 UNEXPECTED_ERROR(__FILE__, __LINE__,
 114                                  isc_msgcat_get(isc_msgcat,
 115                                                 ISC_MSGSET_IFITERSYSCTL,
 116                                                 ISC_MSG_GETIFLIST,
 117                                                 "getting interface list: "
 118                                                 "sysctl: %s"),
 119                                  strbuf);
 120                 result = ISC_R_UNEXPECTED;
 121                 goto failure;
 122         }
 123         iter->bufused = bufused;
 124         INSIST(iter->bufused <= iter->bufsize);
 125
 126         /*
 127          * A newly created iterator has an undefined position
 128          * until isc_interfaceiter_first() is called.
 129          */
 130         iter->pos = (unsigned int) -1;
 131         iter->result = ISC_R_FAILURE;
 132
 133         iter->magic = IFITER_MAGIC;
 134         *iterp = iter;
 135         return (ISC_R_SUCCESS);
 136
 137  failure:
 138         if (iter->buf != NULL)
 139                 isc_mem_put(mctx, iter->buf, iter->bufsize);
 140         isc_mem_put(mctx, iter, sizeof(*iter));
 141         return (result);
 142 }
 143
 144 /*
 145  * Get information about the current interface to iter->current.
 146  * If successful, return ISC_R_SUCCESS.
 147  * If the interface has an unsupported address family,
 148  * return ISC_R_IGNORE.  In case of other failure,
 149  * return ISC_R_UNEXPECTED.
 150  */
 151
 152 static isc_result_t
 153 internal_current(isc_interfaceiter_t *iter) {
 154         struct ifa_msghdr *ifam, *ifam_end;
 155
 156         REQUIRE(VALID_IFITER(iter));
 157         REQUIRE (iter->pos < (unsigned int) iter->bufused);
 158
 159         ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
 160         ifam_end = (struct ifa_msghdr *) ((char *) iter->buf + iter->bufused);
 161
 162         if (ifam->ifam_type == RTM_IFINFO) {
 163                 struct if_msghdr *ifm = (struct if_msghdr *) ifam;
 164                 struct sockaddr_dl *sdl = (struct sockaddr_dl *) (ifm + 1);
 165                 unsigned int namelen;
 166
 167                 memset(&iter->current, 0, sizeof(iter->current));
 168
 169                 namelen = sdl->sdl_nlen;
 170                 if (namelen > sizeof(iter->current.name) - 1)
 171                         namelen = sizeof(iter->current.name) - 1;
 172
 173                 memset(iter->current.name, 0, sizeof(iter->current.name));
 174                 memcpy(iter->current.name, sdl->sdl_data, namelen);
 175
 176                 iter->current.flags = 0;
 177
 178                 if ((ifam->ifam_flags & IFF_UP) != 0)
 179                         iter->current.flags |= INTERFACE_F_UP;
 180
 181                 if ((ifam->ifam_flags & IFF_POINTOPOINT) != 0)
 182                         iter->current.flags |= INTERFACE_F_POINTTOPOINT;
 183
 184                 if ((ifam->ifam_flags & IFF_LOOPBACK) != 0)
 185                         iter->current.flags |= INTERFACE_F_LOOPBACK;
 186
 187                 /*
 188                  * This is not an interface address.
 189                  * Force another iteration.
 190                  */
 191                 return (ISC_R_IGNORE);
 192         } else if (ifam->ifam_type == RTM_NEWADDR) {
 193                 int i;
 194                 int family;
 195                 struct sockaddr *mask_sa = NULL;
 196                 struct sockaddr *addr_sa = NULL;
 197                 struct sockaddr *dst_sa = NULL;
 198
 199                 struct sockaddr *sa = (struct sockaddr *)(ifam + 1);
 200                 family = sa->sa_family;
 201
 202                 for (i = 0; i < RTAX_MAX; i++)
 203                 {
 204                         if ((ifam->ifam_addrs & (1 << i)) == 0)
 205                                 continue;
 206
 207                         INSIST(sa < (struct sockaddr *) ifam_end);
 208
 209                         switch (i) {
 210                         case RTAX_NETMASK: /* Netmask */
 211                                 mask_sa = sa;
 212                                 break;
 213                         case RTAX_IFA: /* Interface address */
 214                                 addr_sa = sa;
 215                                 break;
 216                         case RTAX_BRD: /* Broadcast or destination address */
 217                                 dst_sa = sa;
 218                                 break;
 219                         }
 220 #ifdef ISC_PLATFORM_HAVESALEN
 221                         sa = (struct sockaddr *)((char*)(sa)
 222                                          + ROUNDUP(sa->sa_len));
 223 #else
 224 #ifdef sgi
 225                         /*
 226                          * Do as the contributed SGI code does.
 227                          */
 228                         sa = (struct sockaddr *)((char*)(sa)
 229                                          + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
 230 #else
 231                         /* XXX untested. */
 232                         sa = (struct sockaddr *)((char*)(sa)
 233                                          + ROUNDUP(sizeof(struct sockaddr)));
 234 #endif
 235 #endif
 236                 }
 237
 238                 if (addr_sa == NULL)
 239                         return (ISC_R_IGNORE);
 240
 241                 family = addr_sa->sa_family;
 242                 if (family != AF_INET && family != AF_INET6)
 243                         return (ISC_R_IGNORE);
 244
 245                 iter->current.af = family;
 246
 247                 get_addr(family, &iter->current.address, addr_sa,
 248                          iter->current.name);
 249
 250                 if (mask_sa != NULL)
 251                         get_addr(family, &iter->current.netmask, mask_sa,
 252                                  iter->current.name);
 253
 254                 if (dst_sa != NULL &&
 255                     (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
 256                         get_addr(family, &iter->current.dstaddress, dst_sa,
 257                                  iter->current.name);
 258
 259                 return (ISC_R_SUCCESS);
 260         } else {
 261                 printf(isc_msgcat_get(isc_msgcat, ISC_MSGSET_IFITERSYSCTL,
 262                                       ISC_MSG_UNEXPECTEDTYPE,
 263                                       "warning: unexpected interface list "
 264                                       "message type\n"));
 265                 return (ISC_R_IGNORE);
 266         }
 267 }
 268
 269 /*
 270  * Step the iterator to the next interface.  Unlike
 271  * isc_interfaceiter_next(), this may leave the iterator
 272  * positioned on an interface that will ultimately
 273  * be ignored.  Return ISC_R_NOMORE if there are no more
 274  * interfaces, otherwise ISC_R_SUCCESS.
 275  */
 276 static isc_result_t
 277 internal_next(isc_interfaceiter_t *iter) {
 278         struct ifa_msghdr *ifam;
 279         REQUIRE (iter->pos < (unsigned int) iter->bufused);
 280
 281         ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
 282
 283         iter->pos += ifam->ifam_msglen;
 284
 285         if (iter->pos >= iter->bufused)
 286                 return (ISC_R_NOMORE);
 287
 288         return (ISC_R_SUCCESS);
 289 }
 290
 291 static void
 292 internal_destroy(isc_interfaceiter_t *iter) {
 293         UNUSED(iter); /* Unused. */
 294         /*
 295          * Do nothing.
 296          */
 297 }
 298
 299 static
 300 void internal_first(isc_interfaceiter_t *iter) {
 301         iter->pos = 0;
 302 }