lib/libc/net/getifaddrs.c

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