lib/libc/net/getifaddrs.c

   1 /*      $FreeBSD: src/lib/libc/net/getifaddrs.c,v 1.6 2002/07/25 08:08:30 ume Exp $     */
   2 /*      $DragonFly: src/lib/libc/net/getifaddrs.c,v 1.5 2005/01/31 22:29:33 dillon Exp $        */
   3 /*      $KAME: getifaddrs.c,v 1.9 2001/08/20 02:31:20 itojun Exp $      */
   4
   5 /*
   6  * Copyright (c) 1995, 1999
   7  *      Berkeley Software Design, Inc.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  *      BSDI getifaddrs.c,v 2.12 2000/02/23 14:51:59 dab Exp
  28  */
  29 /*
  30  * NOTE: SIOCGIFCONF case is not LP64 friendly.  it also does not perform
  31  * try-and-error for region size.
  32  */
  33 #include "namespace.h"
  34 #include <sys/types.h>
  35 #include <sys/ioctl.h>
  36 #include <sys/socket.h>
  37 #include <net/if.h>
  38 #ifdef  NET_RT_IFLIST
  39 #include <sys/param.h>
  40 #include <net/route.h>
  41 #include <sys/sysctl.h>
  42 #include <net/if_dl.h>
  43 #endif
  44
  45 #include <errno.h>
  46 #include <ifaddrs.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include "un-namespace.h"
  50
  51 #if !defined(AF_LINK)
  52 #define SA_LEN(sa)      sizeof(struct sockaddr)
  53 #endif
  54
  55 #if !defined(SA_LEN)
  56 #define SA_LEN(sa)      (sa)->sa_len
  57 #endif
  58
  59 #define SALIGN  (sizeof(long) - 1)
  60 #define SA_RLEN(sa)     ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
  61
  62 #ifndef ALIGNBYTES
  63 /*
  64  * On systems with a routing socket, ALIGNBYTES should match the value
  65  * that the kernel uses when building the messages.
  66  */
  67 #define ALIGNBYTES      XXX
  68 #endif
  69 #ifndef ALIGN
  70 #define ALIGN(p)        (((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
  71 #endif
  72
  73 #if     _BSDI_VERSION >= 199701
  74 #define HAVE_IFM_DATA
  75 #endif
  76
  77 #if     _BSDI_VERSION >= 199802
  78 /* ifam_data is very specific to recent versions of bsdi */
  79 #define HAVE_IFAM_DATA
  80 #endif
  81
  82 #if defined(__NetBSD__) || defined(__OpenBSD__) || \
  83     defined(__FreeBSD__) || defined(__DragonFly__)
  84 #define HAVE_IFM_DATA
  85 #endif
  86
  87 #define MAX_SYSCTL_TRY 5
  88
  89 int
  90 getifaddrs(struct ifaddrs **pif)
  91 {
  92         int icnt = 1;
  93         int dcnt = 0;
  94         int ncnt = 0;
  95 #ifdef  NET_RT_IFLIST
  96         int ntry = 0;
  97         int mib[6];
  98         size_t needed;
  99         char *buf;
 100         char *next;
 101         struct ifaddrs *cif = 0;
 102         char *p, *p0;
 103         struct rt_msghdr *rtm;
 104         struct if_msghdr *ifm;
 105         struct ifa_msghdr *ifam;
 106         struct sockaddr_dl *dl;
 107         struct sockaddr *sa;
 108         struct ifaddrs *ifa, *ift;
 109         u_short idx = 0;
 110 #else   /* NET_RT_IFLIST */
 111         char buf[1024];
 112         int m, sock;
 113         struct ifconf ifc;
 114         struct ifreq *ifr;
 115         struct ifreq *lifr;
 116 #endif  /* NET_RT_IFLIST */
 117         int i;
 118         size_t len, alen;
 119         char *data;
 120         char *names;
 121
 122 #ifdef  NET_RT_IFLIST
 123         mib[0] = CTL_NET;
 124         mib[1] = PF_ROUTE;
 125         mib[2] = 0;             /* protocol */
 126         mib[3] = 0;             /* wildcard address family */
 127         mib[4] = NET_RT_IFLIST;
 128         mib[5] = 0;             /* no flags */
 129         do {
 130                 /*
 131                  * We'll try to get addresses several times in case that
 132                  * the number of addresses is unexpectedly increased during
 133                  * the two sysctl calls.  This should rarely happen, but we'll
 134                  * try to do our best for applications that assume success of
 135                  * this library (which should usually be the case).
 136                  * Portability note: since FreeBSD does not add margin of
 137                  * memory at the first sysctl, the possibility of failure on
 138                  * the second sysctl call is a bit higher.
 139                  */
 140
 141                 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
 142                         return (-1);
 143                 if ((buf = malloc(needed)) == NULL)
 144                         return (-1);
 145                 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
 146                         if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
 147                                 free(buf);
 148                                 return (-1);
 149                         }
 150                         free(buf);
 151                         buf = NULL;
 152                 }
 153         } while (buf == NULL);
 154
 155         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 156                 rtm = (struct rt_msghdr *)(void *)next;
 157                 if (rtm->rtm_version != RTM_VERSION)
 158                         continue;
 159                 switch (rtm->rtm_type) {
 160                 case RTM_IFINFO:
 161                         ifm = (struct if_msghdr *)(void *)rtm;
 162                         if (ifm->ifm_addrs & RTA_IFP) {
 163                                 idx = ifm->ifm_index;
 164                                 ++icnt;
 165                                 dl = (struct sockaddr_dl *)(void *)(ifm + 1);
 166                                 dcnt += SA_RLEN((struct sockaddr *)(void*)dl) +
 167                                     ALIGNBYTES;
 168 #ifdef  HAVE_IFM_DATA
 169                                 dcnt += sizeof(ifm->ifm_data);
 170 #endif  /* HAVE_IFM_DATA */
 171                                 ncnt += dl->sdl_nlen + 1;
 172                         } else
 173                                 idx = 0;
 174                         break;
 175
 176                 case RTM_NEWADDR:
 177                         ifam = (struct ifa_msghdr *)(void *)rtm;
 178                         if (idx && ifam->ifam_index != idx)
 179                                 abort();        /* this cannot happen */
 180
 181 #define RTA_MASKS       (RTA_NETMASK | RTA_IFA | RTA_BRD)
 182                         if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
 183                                 break;
 184                         p = (char *)(void *)(ifam + 1);
 185                         ++icnt;
 186 #ifdef  HAVE_IFAM_DATA
 187                         dcnt += sizeof(ifam->ifam_data) + ALIGNBYTES;
 188 #endif  /* HAVE_IFAM_DATA */
 189                         /* Scan to look for length of address */
 190                         alen = 0;
 191                         for (p0 = p, i = 0; i < RTAX_MAX; i++) {
 192                                 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
 193                                     == 0)
 194                                         continue;
 195                                 sa = (struct sockaddr *)(void *)p;
 196                                 len = SA_RLEN(sa);
 197                                 if (i == RTAX_IFA) {
 198                                         alen = len;
 199                                         break;
 200                                 }
 201                                 p += len;
 202                         }
 203                         for (p = p0, i = 0; i < RTAX_MAX; i++) {
 204                                 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
 205                                     == 0)
 206                                         continue;
 207                                 sa = (struct sockaddr *)(void *)p;
 208                                 len = SA_RLEN(sa);
 209                                 if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
 210                                         dcnt += alen;
 211                                 else
 212                                         dcnt += len;
 213                                 p += len;
 214                         }
 215                         break;
 216                 }
 217         }
 218 #else   /* NET_RT_IFLIST */
 219         ifc.ifc_buf = buf;
 220         ifc.ifc_len = sizeof(buf);
 221
 222         if ((sock = _socket(AF_INET, SOCK_STREAM, 0)) < 0)
 223                 return (-1);
 224         i =  _ioctl(sock, SIOCGIFCONF, (char *)&ifc);
 225         _close(sock);
 226         if (i < 0)
 227                 return (-1);
 228
 229         ifr = ifc.ifc_req;
 230         lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
 231
 232         while (ifr < lifr) {
 233                 struct sockaddr *sa;
 234
 235                 sa = &ifr->ifr_addr;
 236                 ++icnt;
 237                 dcnt += SA_RLEN(sa);
 238                 ncnt += sizeof(ifr->ifr_name) + 1;
 239
 240                 if (SA_LEN(sa) < sizeof(*sa))
 241                         ifr = (struct ifreq *)(((char *)sa) + sizeof(*sa));
 242                 else
 243                         ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
 244         }
 245 #endif  /* NET_RT_IFLIST */
 246
 247         if (icnt + dcnt + ncnt == 1) {
 248                 *pif = NULL;
 249                 free(buf);
 250                 return (0);
 251         }
 252         data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
 253         if (data == NULL) {
 254                 free(buf);
 255                 return(-1);
 256         }
 257
 258         ifa = (struct ifaddrs *)(void *)data;
 259         data += sizeof(struct ifaddrs) * icnt;
 260         names = data + dcnt;
 261
 262         memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
 263         ift = ifa;
 264
 265 #ifdef  NET_RT_IFLIST
 266         idx = 0;
 267         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 268                 rtm = (struct rt_msghdr *)(void *)next;
 269                 if (rtm->rtm_version != RTM_VERSION)
 270                         continue;
 271                 switch (rtm->rtm_type) {
 272                 case RTM_IFINFO:
 273                         ifm = (struct if_msghdr *)(void *)rtm;
 274                         if (ifm->ifm_addrs & RTA_IFP) {
 275                                 idx = ifm->ifm_index;
 276                                 dl = (struct sockaddr_dl *)(void *)(ifm + 1);
 277
 278                                 cif = ift;
 279                                 ift->ifa_name = names;
 280                                 ift->ifa_flags = (int)ifm->ifm_flags;
 281                                 memcpy(names, dl->sdl_data,
 282                                     (size_t)dl->sdl_nlen);
 283                                 names[dl->sdl_nlen] = 0;
 284                                 names += dl->sdl_nlen + 1;
 285
 286                                 ift->ifa_addr = (struct sockaddr *)(void *)data;
 287                                 memcpy(data, dl,
 288                                     (size_t)SA_LEN((struct sockaddr *)
 289                                     (void *)dl));
 290                                 data += SA_RLEN((struct sockaddr *)(void *)dl);
 291
 292 #ifdef  HAVE_IFM_DATA
 293                                 /* ifm_data needs to be aligned */
 294                                 ift->ifa_data = data = (void *)ALIGN(data);
 295                                 memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
 296                                 data += sizeof(ifm->ifm_data);
 297 #else   /* HAVE_IFM_DATA */
 298                                 ift->ifa_data = NULL;
 299 #endif  /* HAVE_IFM_DATA */
 300
 301                                 ift = (ift->ifa_next = ift + 1);
 302                         } else
 303                                 idx = 0;
 304                         break;
 305
 306                 case RTM_NEWADDR:
 307                         ifam = (struct ifa_msghdr *)(void *)rtm;
 308                         if (idx && ifam->ifam_index != idx)
 309                                 abort();        /* this cannot happen */
 310
 311                         if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
 312                                 break;
 313                         ift->ifa_name = cif->ifa_name;
 314                         ift->ifa_flags = cif->ifa_flags;
 315                         ift->ifa_data = NULL;
 316                         p = (char *)(void *)(ifam + 1);
 317                         /* Scan to look for length of address */
 318                         alen = 0;
 319                         for (p0 = p, i = 0; i < RTAX_MAX; i++) {
 320                                 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
 321                                     == 0)
 322                                         continue;
 323                                 sa = (struct sockaddr *)(void *)p;
 324                                 len = SA_RLEN(sa);
 325                                 if (i == RTAX_IFA) {
 326                                         alen = len;
 327                                         break;
 328                                 }
 329                                 p += len;
 330                         }
 331                         for (p = p0, i = 0; i < RTAX_MAX; i++) {
 332                                 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
 333                                     == 0)
 334                                         continue;
 335                                 sa = (struct sockaddr *)(void *)p;
 336                                 len = SA_RLEN(sa);
 337                                 switch (i) {
 338                                 case RTAX_IFA:
 339                                         ift->ifa_addr =
 340                                             (struct sockaddr *)(void *)data;
 341                                         memcpy(data, p, len);
 342                                         data += len;
 343                                         break;
 344
 345                                 case RTAX_NETMASK:
 346                                         ift->ifa_netmask =
 347                                             (struct sockaddr *)(void *)data;
 348                                         if (SA_LEN(sa) == 0) {
 349                                                 memset(data, 0, alen);
 350                                                 data += alen;
 351                                                 break;
 352                                         }
 353                                         memcpy(data, p, len);
 354                                         data += len;
 355                                         break;
 356
 357                                 case RTAX_BRD:
 358                                         ift->ifa_broadaddr =
 359                                             (struct sockaddr *)(void *)data;
 360                                         memcpy(data, p, len);
 361                                         data += len;
 362                                         break;
 363                                 }
 364                                 p += len;
 365                         }
 366
 367 #ifdef  HAVE_IFAM_DATA
 368                         /* ifam_data needs to be aligned */
 369                         ift->ifa_data = data = (void *)ALIGN(data);
 370                         memcpy(data, &ifam->ifam_data, sizeof(ifam->ifam_data));
 371                         data += sizeof(ifam->ifam_data);
 372 #endif  /* HAVE_IFAM_DATA */
 373
 374                         ift = (ift->ifa_next = ift + 1);
 375                         break;
 376                 }
 377         }
 378
 379         free(buf);
 380 #else   /* NET_RT_IFLIST */
 381         ifr = ifc.ifc_req;
 382         lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
 383
 384         while (ifr < lifr) {
 385                 struct sockaddr *sa;
 386
 387                 ift->ifa_name = names;
 388                 names[sizeof(ifr->ifr_name)] = 0;
 389                 strncpy(names, ifr->ifr_name, sizeof(ifr->ifr_name));
 390                 while (*names++)
 391                         ;
 392
 393                 ift->ifa_addr = (struct sockaddr *)data;
 394                 sa = &ifr->ifr_addr;
 395                 memcpy(data, sa, SA_LEN(sa));
 396                 data += SA_RLEN(sa);
 397
 398                 ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
 399                 ift = (ift->ifa_next = ift + 1);
 400         }
 401 #endif  /* NET_RT_IFLIST */
 402         if (--ift >= ifa) {
 403                 ift->ifa_next = NULL;
 404                 *pif = ifa;
 405         } else {
 406                 *pif = NULL;
 407                 free(ifa);
 408         }
 409         return (0);
 410 }
 411
 412 void
 413 freeifaddrs(struct ifaddrs *ifp)
 414 {
 415
 416         free(ifp);
 417 }