lib/libc/net/getifmaddrs.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2003 Bruce M. Simpson.
   5  * 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  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include "namespace.h"
  33 #include <sys/param.h>
  34 #include <sys/sysctl.h>
  35 #include <sys/ioctl.h>
  36 #include <sys/socket.h>
  37 #include <net/if.h>
  38 #include <net/if_dl.h>
  39 #include <net/route.h>
  40
  41 #include <errno.h>
  42 #include <ifaddrs.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include "un-namespace.h"
  46
  47 #define SALIGN  (sizeof(long) - 1)
  48 #define SA_RLEN(sa)     ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : \
  49                             (SALIGN + 1))
  50 #define MAX_SYSCTL_TRY  5
  51 #define RTA_MASKS       (RTA_GATEWAY | RTA_IFP | RTA_IFA)
  52
  53 int
  54 getifmaddrs(struct ifmaddrs **pif)
  55 {
  56         int icnt = 1;
  57         int dcnt = 0;
  58         int ntry = 0;
  59         size_t len;
  60         size_t needed;
  61         int mib[6];
  62         int i;
  63         char *buf;
  64         char *data;
  65         char *next;
  66         char *p;
  67         struct ifma_msghdr *ifmam;
  68         struct ifmaddrs *ifa, *ift;
  69         struct rt_msghdr *rtm;
  70         struct sockaddr *sa;
  71
  72         mib[0] = CTL_NET;
  73         mib[1] = PF_ROUTE;
  74         mib[2] = 0;             /* protocol */
  75         mib[3] = 0;             /* wildcard address family */
  76         mib[4] = NET_RT_IFMALIST;
  77         mib[5] = 0;             /* no flags */
  78         do {
  79                 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
  80                         return (-1);
  81                 if ((buf = malloc(needed)) == NULL)
  82                         return (-1);
  83                 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
  84                         if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
  85                                 free(buf);
  86                                 return (-1);
  87                         }
  88                         free(buf);
  89                         buf = NULL;
  90                 }
  91         } while (buf == NULL);
  92
  93         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
  94                 rtm = (struct rt_msghdr *)(void *)next;
  95                 if (rtm->rtm_version != RTM_VERSION)
  96                         continue;
  97                 switch (rtm->rtm_type) {
  98                 case RTM_NEWMADDR:
  99                         ifmam = (struct ifma_msghdr *)(void *)rtm;
 100                         if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
 101                                 break;
 102                         icnt++;
 103                         p = (char *)(ifmam + 1);
 104                         for (i = 0; i < RTAX_MAX; i++) {
 105                                 if ((RTA_MASKS & ifmam->ifmam_addrs &
 106                                     (1 << i)) == 0)
 107                                         continue;
 108                                 sa = (struct sockaddr *)(void *)p;
 109                                 len = SA_RLEN(sa);
 110                                 dcnt += len;
 111                                 p += len;
 112                         }
 113                         break;
 114                 }
 115         }
 116
 117         data = malloc(sizeof(struct ifmaddrs) * icnt + dcnt);
 118         if (data == NULL) {
 119                 free(buf);
 120                 return (-1);
 121         }
 122
 123         ifa = (struct ifmaddrs *)(void *)data;
 124         data += sizeof(struct ifmaddrs) * icnt;
 125
 126         memset(ifa, 0, sizeof(struct ifmaddrs) * icnt);
 127         ift = ifa;
 128
 129         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 130                 rtm = (struct rt_msghdr *)(void *)next;
 131                 if (rtm->rtm_version != RTM_VERSION)
 132                         continue;
 133
 134                 switch (rtm->rtm_type) {
 135                 case RTM_NEWMADDR:
 136                         ifmam = (struct ifma_msghdr *)(void *)rtm;
 137                         if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
 138                                 break;
 139
 140                         p = (char *)(ifmam + 1);
 141                         for (i = 0; i < RTAX_MAX; i++) {
 142                                 if ((RTA_MASKS & ifmam->ifmam_addrs &
 143                                     (1 << i)) == 0)
 144                                         continue;
 145                                 sa = (struct sockaddr *)(void *)p;
 146                                 len = SA_RLEN(sa);
 147                                 switch (i) {
 148                                 case RTAX_GATEWAY:
 149                                         ift->ifma_lladdr =
 150                                             (struct sockaddr *)(void *)data;
 151                                         memcpy(data, p, len);
 152                                         data += len;
 153                                         break;
 154
 155                                 case RTAX_IFP:
 156                                         ift->ifma_name =
 157                                             (struct sockaddr *)(void *)data;
 158                                         memcpy(data, p, len);
 159                                         data += len;
 160                                         break;
 161
 162                                 case RTAX_IFA:
 163                                         ift->ifma_addr =
 164                                             (struct sockaddr *)(void *)data;
 165                                         memcpy(data, p, len);
 166                                         data += len;
 167                                         break;
 168
 169                                 default:
 170                                         data += len;
 171                                         break;
 172                                 }
 173                                 p += len;
 174                         }
 175                         ift->ifma_next = ift + 1;
 176                         ift = ift->ifma_next;
 177                         break;
 178                 }
 179         }
 180
 181         free(buf);
 182
 183         if (ift > ifa) {
 184                 ift--;
 185                 ift->ifma_next = NULL;
 186                 *pif = ifa;
 187         } else {
 188                 *pif = NULL;
 189                 free(ifa);
 190         }
 191         return (0);
 192 }
 193
 194 void
 195 freeifmaddrs(struct ifmaddrs *ifmp)
 196 {
 197
 198         free(ifmp);
 199 }