lib/libc/net/getifmaddrs.c

   1 /*
   2  * Copyright (c) 2003 Bruce M. Simpson.
   3  * All rights reserved
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include "namespace.h"
  31 #include <sys/param.h>
  32 #include <sys/sysctl.h>
  33 #include <sys/ioctl.h>
  34 #include <sys/socket.h>
  35 #include <net/if.h>
  36 #include <net/if_dl.h>
  37 #include <net/route.h>
  38
  39 #include <errno.h>
  40 #include <ifaddrs.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include "un-namespace.h"
  44
  45 #define SALIGN  (sizeof(long) - 1)
  46 #define SA_RLEN(sa)     ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : \
  47                             (SALIGN + 1))
  48 #define MAX_SYSCTL_TRY  5
  49 #define RTA_MASKS       (RTA_GATEWAY | RTA_IFP | RTA_IFA)
  50
  51 int
  52 getifmaddrs(struct ifmaddrs **pif)
  53 {
  54         int icnt = 1;
  55         int dcnt = 0;
  56         int ntry = 0;
  57         size_t len;
  58         size_t needed;
  59         int mib[6];
  60         int i;
  61         char *buf;
  62         char *data;
  63         char *next;
  64         char *p;
  65         struct ifma_msghdr *ifmam;
  66         struct ifmaddrs *ifa, *ift;
  67         struct rt_msghdr *rtm;
  68         struct sockaddr *sa;
  69
  70         mib[0] = CTL_NET;
  71         mib[1] = PF_ROUTE;
  72         mib[2] = 0;             /* protocol */
  73         mib[3] = 0;             /* wildcard address family */
  74         mib[4] = NET_RT_IFMALIST;
  75         mib[5] = 0;             /* no flags */
  76         do {
  77                 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
  78                         return (-1);
  79                 if ((buf = malloc(needed)) == NULL)
  80                         return (-1);
  81                 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
  82                         if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
  83                                 free(buf);
  84                                 return (-1);
  85                         }
  86                         free(buf);
  87                         buf = NULL;
  88                 }
  89         } while (buf == NULL);
  90
  91         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
  92                 rtm = (struct rt_msghdr *)(void *)next;
  93                 if (rtm->rtm_version != RTM_VERSION)
  94                         continue;
  95                 switch (rtm->rtm_type) {
  96                 case RTM_NEWMADDR:
  97                         ifmam = (struct ifma_msghdr *)(void *)rtm;
  98                         if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
  99                                 break;
 100                         icnt++;
 101                         p = (char *)(ifmam + 1);
 102                         for (i = 0; i < RTAX_MAX; i++) {
 103                                 if ((RTA_MASKS & ifmam->ifmam_addrs &
 104                                     (1 << i)) == 0)
 105                                         continue;
 106                                 sa = (struct sockaddr *)(void *)p;
 107                                 len = SA_RLEN(sa);
 108                                 dcnt += len;
 109                                 p += len;
 110                         }
 111                         break;
 112                 }
 113         }
 114
 115         data = malloc(sizeof(struct ifmaddrs) * icnt + dcnt);
 116         if (data == NULL) {
 117                 free(buf);
 118                 return (-1);
 119         }
 120
 121         ifa = (struct ifmaddrs *)(void *)data;
 122         data += sizeof(struct ifmaddrs) * icnt;
 123
 124         memset(ifa, 0, sizeof(struct ifmaddrs) * icnt);
 125         ift = ifa;
 126
 127         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 128                 rtm = (struct rt_msghdr *)(void *)next;
 129                 if (rtm->rtm_version != RTM_VERSION)
 130                         continue;
 131
 132                 switch (rtm->rtm_type) {
 133                 case RTM_NEWMADDR:
 134                         ifmam = (struct ifma_msghdr *)(void *)rtm;
 135                         if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
 136                                 break;
 137
 138                         p = (char *)(ifmam + 1);
 139                         for (i = 0; i < RTAX_MAX; i++) {
 140                                 if ((RTA_MASKS & ifmam->ifmam_addrs &
 141                                     (1 << i)) == 0)
 142                                         continue;
 143                                 sa = (struct sockaddr *)(void *)p;
 144                                 len = SA_RLEN(sa);
 145                                 switch (i) {
 146                                 case RTAX_GATEWAY:
 147                                         ift->ifma_lladdr =
 148                                             (struct sockaddr *)(void *)data;
 149                                         memcpy(data, p, len);
 150                                         data += len;
 151                                         break;
 152
 153                                 case RTAX_IFP:
 154                                         ift->ifma_name =
 155                                             (struct sockaddr *)(void *)data;
 156                                         memcpy(data, p, len);
 157                                         data += len;
 158                                         break;
 159
 160                                 case RTAX_IFA:
 161                                         ift->ifma_addr =
 162                                             (struct sockaddr *)(void *)data;
 163                                         memcpy(data, p, len);
 164                                         data += len;
 165                                         break;
 166
 167                                 default:
 168                                         data += len;
 169                                         break;
 170                                 }
 171                                 p += len;
 172                         }
 173                         ift->ifma_next = ift + 1;
 174                         ift = ift->ifma_next;
 175                         break;
 176                 }
 177         }
 178
 179         free(buf);
 180
 181         if (ift > ifa) {
 182                 ift--;
 183                 ift->ifma_next = NULL;
 184                 *pif = ifa;
 185         } else {
 186                 *pif = NULL;
 187                 free(ifa);
 188         }
 189         return (0);
 190 }
 191
 192 void
 193 freeifmaddrs(struct ifmaddrs *ifmp)
 194 {
 195
 196         free(ifmp);
 197 }