contrib/ntp/libisc/ifiter_sysctl.c

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and 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 1.14.12.7 2004/03/08 09:04:56 marka Exp $ */
  19
  20 /*
  21  * Obtain the list of network interfaces using sysctl.
  22  * See TCP/IP Illustrated Volume 2, sections 19.8, 19.14,
  23  * and 19.16.
  24  */
  25
  26 #include <sys/param.h>
  27 #include <sys/sysctl.h>
  28
  29 #include <net/route.h>
  30 #include <net/if_dl.h>
  31
  32 /* XXX what about Alpha? */
  33 #ifdef sgi
  34 #define ROUNDUP(a) ((a) > 0 ? \
  35                 (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) : \
  36                 sizeof(__uint64_t))
  37 #else
  38 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
  39                     : sizeof(long))
  40 #endif
  41
  42 #define IFITER_MAGIC            ISC_MAGIC('I', 'F', 'I', 'S')
  43 #define VALID_IFITER(t)         ISC_MAGIC_VALID(t, IFITER_MAGIC)
  44
  45 struct isc_interfaceiter {
  46         unsigned int            magic;          /* Magic number. */
  47         isc_mem_t               *mctx;
  48         void                    *buf;           /* Buffer for sysctl data. */
  49         unsigned int            bufsize;        /* Bytes allocated. */
  50         unsigned int            bufused;        /* Bytes used. */
  51         unsigned int            pos;            /* Current offset in
  52                                                    sysctl data. */
  53         isc_interface_t         current;        /* Current interface data. */
  54         isc_result_t            result;         /* Last result code. */
  55 };
  56
  57 static int mib[6] = {
  58         CTL_NET,
  59         PF_ROUTE,
  60         0,
  61         0,                      /* Any address family. */
  62         NET_RT_IFLIST,
  63         0                       /* Flags. */
  64 };
  65
  66 isc_result_t
  67 isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
  68         isc_interfaceiter_t *iter;
  69         isc_result_t result;
  70         size_t bufsize;
  71         size_t bufused;
  72         char strbuf[ISC_STRERRORSIZE];
  73
  74         REQUIRE(iterp != NULL);
  75         REQUIRE(*iterp == NULL);
  76
  77         iter = isc_mem_get(mctx, sizeof(*iter));
  78         if (iter == NULL)
  79                 return (ISC_R_NOMEMORY);
  80
  81         iter->mctx = mctx;
  82         iter->buf = 0;
  83
  84         /*
  85          * Determine the amount of memory needed.
  86          */
  87         bufsize = 0;
  88         if (sysctl(mib, 6, NULL, &bufsize, NULL, (size_t) 0) < 0) {
  89                 isc__strerror(errno, strbuf, sizeof(strbuf));
  90                 UNEXPECTED_ERROR(__FILE__, __LINE__,
  91                                  isc_msgcat_get(isc_msgcat,
  92                                                 ISC_MSGSET_IFITERSYSCTL,
  93                                                 ISC_MSG_GETIFLISTSIZE,
  94                                                 "getting interface "
  95                                                 "list size: sysctl: %s"),
  96                                  strbuf);
  97                 result = ISC_R_UNEXPECTED;
  98                 goto failure;
  99         }
 100         iter->bufsize = bufsize;
 101
 102         iter->buf = isc_mem_get(iter->mctx, iter->bufsize);
 103         if (iter->buf == NULL) {
 104                 result = ISC_R_NOMEMORY;
 105                 goto failure;
 106         }
 107
 108         bufused = bufsize;
 109         if (sysctl(mib, 6, iter->buf, &bufused, NULL, (size_t) 0) < 0) {
 110                 isc__strerror(errno, strbuf, sizeof(strbuf));
 111                 UNEXPECTED_ERROR(__FILE__, __LINE__,
 112                                  isc_msgcat_get(isc_msgcat,
 113                                                 ISC_MSGSET_IFITERSYSCTL,
 114                                                 ISC_MSG_GETIFLIST,
 115                                                 "getting interface list: "
 116                                                 "sysctl: %s"),
 117                                  strbuf);
 118                 result = ISC_R_UNEXPECTED;
 119                 goto failure;
 120         }
 121         iter->bufused = bufused;
 122         INSIST(iter->bufused <= iter->bufsize);
 123
 124         /*
 125          * A newly created iterator has an undefined position
 126          * until isc_interfaceiter_first() is called.
 127          */
 128         iter->pos = (unsigned int) -1;
 129         iter->result = ISC_R_FAILURE;
 130
 131         iter->magic = IFITER_MAGIC;
 132         *iterp = iter;
 133         return (ISC_R_SUCCESS);
 134
 135  failure:
 136         if (iter->buf != NULL)
 137                 isc_mem_put(mctx, iter->buf, iter->bufsize);
 138         isc_mem_put(mctx, iter, sizeof(*iter));
 139         return (result);
 140 }
 141
 142 /*
 143  * Get information about the current interface to iter->current.
 144  * If successful, return ISC_R_SUCCESS.
 145  * If the interface has an unsupported address family,
 146  * return ISC_R_IGNORE.  In case of other failure,
 147  * return ISC_R_UNEXPECTED.
 148  */
 149
 150 static isc_result_t
 151 internal_current(isc_interfaceiter_t *iter) {
 152         struct ifa_msghdr *ifam, *ifam_end;
 153
 154         REQUIRE(VALID_IFITER(iter));
 155         REQUIRE (iter->pos < (unsigned int) iter->bufused);
 156
 157         ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
 158         ifam_end = (struct ifa_msghdr *) ((char *) iter->buf + iter->bufused);
 159
 160         if (ifam->ifam_type == RTM_IFINFO) {
 161                 struct if_msghdr *ifm = (struct if_msghdr *) ifam;
 162                 struct sockaddr_dl *sdl = (struct sockaddr_dl *) (ifm + 1);
 163                 unsigned int namelen;
 164
 165                 memset(&iter->current, 0, sizeof(iter->current));
 166
 167                 namelen = sdl->sdl_nlen;
 168                 if (namelen > sizeof(iter->current.name) - 1)
 169                         namelen = sizeof(iter->current.name) - 1;
 170
 171                 memset(iter->current.name, 0, sizeof(iter->current.name));
 172                 memcpy(iter->current.name, sdl->sdl_data, namelen);
 173
 174                 iter->current.flags = 0;
 175
 176                 if ((ifam->ifam_flags & IFF_UP) != 0)
 177                         iter->current.flags |= INTERFACE_F_UP;
 178
 179                 if ((ifam->ifam_flags & IFF_POINTOPOINT) != 0)
 180                         iter->current.flags |= INTERFACE_F_POINTTOPOINT;
 181
 182                 if ((ifam->ifam_flags & IFF_LOOPBACK) != 0)
 183                         iter->current.flags |= INTERFACE_F_LOOPBACK;
 184
 185                 if ((ifam->ifam_flags & IFF_BROADCAST) != 0) {
 186                         iter->current.flags |= INTERFACE_F_BROADCAST;
 187                 }
 188 #ifdef IFF_MULTICAST
 189                 if ((ifam->ifam_flags & IFF_MULTICAST) != 0) {
 190                         iter->current.flags |= INTERFACE_F_MULTICAST;
 191                 }
 192 #endif
 193
 194                 /*
 195                  * This is not an interface address.
 196                  * Force another iteration.
 197                  */
 198                 return (ISC_R_IGNORE);
 199         } else if (ifam->ifam_type == RTM_NEWADDR) {
 200                 int i;
 201                 int family;
 202                 struct sockaddr *mask_sa = NULL;
 203                 struct sockaddr *addr_sa = NULL;
 204                 struct sockaddr *dst_sa = NULL;
 205
 206                 struct sockaddr *sa = (struct sockaddr *)(ifam + 1);
 207                 family = sa->sa_family;
 208
 209                 for (i = 0; i < RTAX_MAX; i++)
 210                 {
 211                         if ((ifam->ifam_addrs & (1 << i)) == 0)
 212                                 continue;
 213
 214                         INSIST(sa < (struct sockaddr *) ifam_end);
 215
 216                         switch (i) {
 217                         case RTAX_NETMASK: /* Netmask */
 218                                 mask_sa = sa;
 219                                 break;
 220                         case RTAX_IFA: /* Interface address */
 221                                 addr_sa = sa;
 222                                 break;
 223                         case RTAX_BRD: /* Broadcast or destination address */
 224                                 dst_sa = sa;
 225                                 break;
 226                         }
 227 #ifdef ISC_PLATFORM_HAVESALEN
 228                         sa = (struct sockaddr *)((char*)(sa)
 229                                          + ROUNDUP(sa->sa_len));
 230 #else
 231 #ifdef sgi
 232                         /*
 233                          * Do as the contributed SGI code does.
 234                          */
 235                         sa = (struct sockaddr *)((char*)(sa)
 236                                          + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
 237 #else
 238                         /* XXX untested. */
 239                         sa = (struct sockaddr *)((char*)(sa)
 240                                          + ROUNDUP(sizeof(struct sockaddr)));
 241 #endif
 242 #endif
 243                 }
 244
 245                 if (addr_sa == NULL)
 246                         return (ISC_R_IGNORE);
 247
 248                 family = addr_sa->sa_family;
 249                 if (family != AF_INET && family != AF_INET6)
 250                         return (ISC_R_IGNORE);
 251
 252                 iter->current.af = family;
 253
 254                 get_addr(family, &iter->current.address, addr_sa,
 255                          iter->current.name);
 256
 257                 if (mask_sa != NULL)
 258                         get_addr(family, &iter->current.netmask, mask_sa,
 259                                  iter->current.name);
 260
 261                 if (dst_sa != NULL &&
 262                     (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
 263                         get_addr(family, &iter->current.dstaddress, dst_sa,
 264                                  iter->current.name);
 265
 266                 if (dst_sa != NULL &&
 267                     (iter->current.flags & INTERFACE_F_BROADCAST) != 0)
 268                         get_addr(family, &iter->current.broadcast, dst_sa,
 269                                  iter->current.name);
 270
 271
 272                 return (ISC_R_SUCCESS);
 273         } else {
 274                 printf(isc_msgcat_get(isc_msgcat, ISC_MSGSET_IFITERSYSCTL,
 275                                       ISC_MSG_UNEXPECTEDTYPE,
 276                                       "warning: unexpected interface list "
 277                                       "message type\n"));
 278                 return (ISC_R_IGNORE);
 279         }
 280 }
 281
 282 /*
 283  * Step the iterator to the next interface.  Unlike
 284  * isc_interfaceiter_next(), this may leave the iterator
 285  * positioned on an interface that will ultimately
 286  * be ignored.  Return ISC_R_NOMORE if there are no more
 287  * interfaces, otherwise ISC_R_SUCCESS.
 288  */
 289 static isc_result_t
 290 internal_next(isc_interfaceiter_t *iter) {
 291         struct ifa_msghdr *ifam;
 292         REQUIRE (iter->pos < (unsigned int) iter->bufused);
 293
 294         ifam = (struct ifa_msghdr *) ((char *) iter->buf + iter->pos);
 295
 296         iter->pos += ifam->ifam_msglen;
 297
 298         if (iter->pos >= iter->bufused)
 299                 return (ISC_R_NOMORE);
 300
 301         return (ISC_R_SUCCESS);
 302 }
 303
 304 static void
 305 internal_destroy(isc_interfaceiter_t *iter) {
 306         UNUSED(iter); /* Unused. */
 307         /*
 308          * Do nothing.
 309          */
 310 }
 311
 312 static
 313 void internal_first(isc_interfaceiter_t *iter) {
 314         iter->pos = 0;
 315 }