lib/libc/net/getifaddrs.c

   1 /*      $KAME: getifaddrs.c,v 1.9 2001/08/20 02:31:20 itojun Exp $      */
   2
   3 /*-
   4  * SPDX-License-Identifier: BSD-1-Clause
   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
  34 #include "namespace.h"
  35 #include <sys/types.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/socket.h>
  38 #include <net/if.h>
  39 #ifdef  NET_RT_IFLIST
  40 #include <sys/param.h>
  41 #include <net/route.h>
  42 #include <sys/sysctl.h>
  43 #include <net/if_dl.h>
  44 #endif
  45
  46 #include <errno.h>
  47 #include <ifaddrs.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include "un-namespace.h"
  51
  52 #if !defined(AF_LINK)
  53 #define SA_LEN(sa)      sizeof(struct sockaddr)
  54 #endif
  55
  56 #if !defined(SA_LEN)
  57 #define SA_LEN(sa)      (sa)->sa_len
  58 #endif
  59
  60 #define SALIGN  (sizeof(long) - 1)
  61 #define SA_RLEN(sa)     ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
  62
  63 #ifndef ALIGNBYTES
  64 /*
  65  * On systems with a routing socket, ALIGNBYTES should match the value
  66  * that the kernel uses when building the messages.
  67  */
  68 #define ALIGNBYTES      XXX
  69 #endif
  70 #ifndef ALIGN
  71 #define ALIGN(p)        (((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
  72 #endif
  73
  74 #define MAX_SYSCTL_TRY 5
  75
  76 int
  77 getifaddrs(struct ifaddrs **pif)
  78 {
  79         int icnt = 1;
  80         int dcnt = 0;
  81         int ncnt = 0;
  82         int ntry = 0;
  83         int mib[6];
  84         size_t needed;
  85         char *buf;
  86         char *next;
  87         struct ifaddrs *cif;
  88         char *p, *p0;
  89         struct rt_msghdr *rtm;
  90         struct if_msghdrl *ifm;
  91         struct ifa_msghdrl *ifam;
  92         struct sockaddr_dl *dl;
  93         struct sockaddr *sa;
  94         struct ifaddrs *ifa, *ift;
  95         struct if_data *if_data;
  96         u_short idx = 0;
  97         int i;
  98         size_t len, alen;
  99         char *data;
 100         char *names;
 101
 102         mib[0] = CTL_NET;
 103         mib[1] = PF_ROUTE;
 104         mib[2] = 0;             /* protocol */
 105         mib[3] = 0;             /* wildcard address family */
 106         mib[4] = NET_RT_IFLISTL;/* extra fields for extensible msghdr structs */
 107         mib[5] = 0;             /* no flags */
 108         do {
 109                 /*
 110                  * We'll try to get addresses several times in case that
 111                  * the number of addresses is unexpectedly increased during
 112                  * the two sysctl calls.  This should rarely happen, but we'll
 113                  * try to do our best for applications that assume success of
 114                  * this library (which should usually be the case).
 115                  * Portability note: since FreeBSD does not add margin of
 116                  * memory at the first sysctl, the possibility of failure on
 117                  * the second sysctl call is a bit higher.
 118                  */
 119
 120                 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
 121                         return (-1);
 122                 if ((buf = malloc(needed)) == NULL)
 123                         return (-1);
 124                 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
 125                         if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
 126                                 free(buf);
 127                                 return (-1);
 128                         }
 129                         free(buf);
 130                         buf = NULL;
 131                 }
 132         } while (buf == NULL);
 133
 134         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 135                 rtm = (struct rt_msghdr *)(void *)next;
 136                 if (rtm->rtm_version != RTM_VERSION)
 137                         continue;
 138                 switch (rtm->rtm_type) {
 139                 case RTM_IFINFO:
 140                         ifm = (struct if_msghdrl *)(void *)rtm;
 141                         if (ifm->ifm_addrs & RTA_IFP) {
 142                                 idx = ifm->ifm_index;
 143                                 ++icnt;
 144                                 if_data = IF_MSGHDRL_IFM_DATA(ifm);
 145                                 dcnt += if_data->ifi_datalen;
 146                                 dl = (struct sockaddr_dl *)IF_MSGHDRL_RTA(ifm);
 147                                 dcnt += SA_RLEN((struct sockaddr *)(void*)dl) +
 148                                     ALIGNBYTES;
 149                                 ncnt += dl->sdl_nlen + 1;
 150                         } else
 151                                 idx = 0;
 152                         break;
 153
 154                 case RTM_NEWADDR:
 155                         ifam = (struct ifa_msghdrl *)(void *)rtm;
 156                         if (idx && ifam->ifam_index != idx)
 157                                 abort();        /* this cannot happen */
 158
 159 #define RTA_MASKS       (RTA_NETMASK | RTA_IFA | RTA_BRD)
 160                         if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
 161                                 break;
 162                         p = (char *)IFA_MSGHDRL_RTA(ifam);
 163                         ++icnt;
 164                         if_data = IFA_MSGHDRL_IFAM_DATA(ifam);
 165                         dcnt += if_data->ifi_datalen + ALIGNBYTES;
 166
 167                         /* Scan to look for length of address */
 168                         alen = 0;
 169                         for (p0 = p, i = 0; i < RTAX_MAX; i++) {
 170                                 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
 171                                     == 0)
 172                                         continue;
 173                                 sa = (struct sockaddr *)(void *)p;
 174                                 len = SA_RLEN(sa);
 175                                 if (i == RTAX_IFA) {
 176                                         alen = len;
 177                                         break;
 178                                 }
 179                                 p += len;
 180                         }
 181                         for (p = p0, i = 0; i < RTAX_MAX; i++) {
 182                                 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
 183                                     == 0)
 184                                         continue;
 185                                 sa = (struct sockaddr *)(void *)p;
 186                                 len = SA_RLEN(sa);
 187                                 if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
 188                                         dcnt += alen;
 189                                 else
 190                                         dcnt += len;
 191                                 p += len;
 192                         }
 193                         break;
 194                 }
 195         }
 196
 197         if (icnt + dcnt + ncnt == 1) {
 198                 *pif = NULL;
 199                 free(buf);
 200                 return (0);
 201         }
 202         data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
 203         if (data == NULL) {
 204                 free(buf);
 205                 return(-1);
 206         }
 207
 208         ifa = (struct ifaddrs *)(void *)data;
 209         data += sizeof(struct ifaddrs) * icnt;
 210         names = data + dcnt;
 211
 212         memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
 213         ift = ifa;
 214
 215         idx = 0;
 216         cif = NULL;
 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 }