lib/libc/net/getifmaddrs.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause
   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 "namespace.h"
  30 #include <sys/param.h>
  31 #include <sys/sysctl.h>
  32 #include <sys/ioctl.h>
  33 #include <sys/socket.h>
  34 #include <net/if.h>
  35 #include <net/if_dl.h>
  36 #include <net/route.h>
  37
  38 #include <errno.h>
  39 #include <ifaddrs.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include "un-namespace.h"
  43
  44 #define SALIGN  (sizeof(long) - 1)
  45 #define SA_RLEN(sa)     ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : \
  46                             (SALIGN + 1))
  47 #define MAX_SYSCTL_TRY  5
  48 #define RTA_MASKS       (RTA_GATEWAY | RTA_IFP | RTA_IFA)
  49
  50 int
  51 getifmaddrs(struct ifmaddrs **pif)
  52 {
  53         int icnt = 1;
  54         int dcnt = 0;
  55         int ntry = 0;
  56         size_t len;
  57         size_t needed;
  58         int mib[6];
  59         int i;
  60         char *buf;
  61         char *data;
  62         char *next;
  63         char *p;
  64         struct ifma_msghdr *ifmam;
  65         struct ifmaddrs *ifa, *ift;
  66         struct rt_msghdr *rtm;
  67         struct sockaddr *sa;
  68
  69         mib[0] = CTL_NET;
  70         mib[1] = PF_ROUTE;
  71         mib[2] = 0;             /* protocol */
  72         mib[3] = 0;             /* wildcard address family */
  73         mib[4] = NET_RT_IFMALIST;
  74         mib[5] = 0;             /* no flags */
  75         do {
  76                 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
  77                         return (-1);
  78                 if ((buf = malloc(needed)) == NULL)
  79                         return (-1);
  80                 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
  81                         if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
  82                                 free(buf);
  83                                 return (-1);
  84                         }
  85                         free(buf);
  86                         buf = NULL;
  87                 }
  88         } while (buf == NULL);
  89
  90         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
  91                 rtm = (struct rt_msghdr *)(void *)next;
  92                 if (rtm->rtm_version != RTM_VERSION)
  93                         continue;
  94                 switch (rtm->rtm_type) {
  95                 case RTM_NEWMADDR:
  96                         ifmam = (struct ifma_msghdr *)(void *)rtm;
  97                         if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
  98                                 break;
  99                         icnt++;
 100                         p = (char *)(ifmam + 1);
 101                         for (i = 0; i < RTAX_MAX; i++) {
 102                                 if ((RTA_MASKS & ifmam->ifmam_addrs &
 103                                     (1 << i)) == 0)
 104                                         continue;
 105                                 sa = (struct sockaddr *)(void *)p;
 106                                 len = SA_RLEN(sa);
 107                                 dcnt += len;
 108                                 p += len;
 109                         }
 110                         break;
 111                 }
 112         }
 113
 114         data = malloc(sizeof(struct ifmaddrs) * icnt + dcnt);
 115         if (data == NULL) {
 116                 free(buf);
 117                 return (-1);
 118         }
 119
 120         ifa = (struct ifmaddrs *)(void *)data;
 121         data += sizeof(struct ifmaddrs) * icnt;
 122
 123         memset(ifa, 0, sizeof(struct ifmaddrs) * icnt);
 124         ift = ifa;
 125
 126         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 127                 rtm = (struct rt_msghdr *)(void *)next;
 128                 if (rtm->rtm_version != RTM_VERSION)
 129                         continue;
 130
 131                 switch (rtm->rtm_type) {
 132                 case RTM_NEWMADDR:
 133                         ifmam = (struct ifma_msghdr *)(void *)rtm;
 134                         if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
 135                                 break;
 136
 137                         p = (char *)(ifmam + 1);
 138                         for (i = 0; i < RTAX_MAX; i++) {
 139                                 if ((RTA_MASKS & ifmam->ifmam_addrs &
 140                                     (1 << i)) == 0)
 141                                         continue;
 142                                 sa = (struct sockaddr *)(void *)p;
 143                                 len = SA_RLEN(sa);
 144                                 switch (i) {
 145                                 case RTAX_GATEWAY:
 146                                         ift->ifma_lladdr =
 147                                             (struct sockaddr *)(void *)data;
 148                                         memcpy(data, p, len);
 149                                         data += len;
 150                                         break;
 151
 152                                 case RTAX_IFP:
 153                                         ift->ifma_name =
 154                                             (struct sockaddr *)(void *)data;
 155                                         memcpy(data, p, len);
 156                                         data += len;
 157                                         break;
 158
 159                                 case RTAX_IFA:
 160                                         ift->ifma_addr =
 161                                             (struct sockaddr *)(void *)data;
 162                                         memcpy(data, p, len);
 163                                         data += len;
 164                                         break;
 165
 166                                 default:
 167                                         data += len;
 168                                         break;
 169                                 }
 170                                 p += len;
 171                         }
 172                         ift->ifma_next = ift + 1;
 173                         ift = ift->ifma_next;
 174                         break;
 175                 }
 176         }
 177
 178         free(buf);
 179
 180         if (ift > ifa) {
 181                 ift--;
 182                 ift->ifma_next = NULL;
 183                 *pif = ifa;
 184         } else {
 185                 *pif = NULL;
 186                 free(ifa);
 187         }
 188         return (0);
 189 }
 190
 191 void
 192 freeifmaddrs(struct ifmaddrs *ifmp)
 193 {
 194
 195         free(ifmp);
 196 }