usr.sbin/portmap/from_local.c

   1  /*
   2   * Check if an address belongs to the local system. Adapted from:
   3   *
   4   * @(#)pmap_svc.c 1.32 91/03/11 Copyright 1984,1990 Sun Microsystems, Inc.
   5   * @(#)get_myaddress.c  2.1 88/07/29 4.0 RPCSRC.
   6   */
   7
   8 /*
   9  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
  10  * unrestricted use provided that this legend is included on all tape
  11  * media and as a part of the software program in whole or part.  Users
  12  * may copy or modify Sun RPC without charge, but are not authorized
  13  * to license or distribute it to anyone else except as part of a product or
  14  * program developed by the user or with the express written consent of
  15  * Sun Microsystems, Inc.
  16  *
  17  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  18  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  19  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  20  *
  21  * Sun RPC is provided with no support and without any obligation on the
  22  * part of Sun Microsystems, Inc. to assist in its use, correction,
  23  * modification or enhancement.
  24  *
  25  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  26  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  27  * OR ANY PART THEREOF.
  28  *
  29  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  30  * or profits or other special, indirect and consequential damages, even if
  31  * Sun has been advised of the possibility of such damages.
  32  *
  33  * Sun Microsystems, Inc.
  34  * 2550 Garcia Avenue
  35  * Mountain View, California  94043
  36  *
  37  * @(#) from_local.c 1.2 93/11/16 21:50:02
  38  * $FreeBSD: src/usr.sbin/portmap/from_local.c,v 1.10.2.1 2000/08/16 14:04:37 brian Exp $
  39  * $DragonFly: src/usr.sbin/portmap/from_local.c,v 1.3 2004/03/30 02:58:59 cpressey Exp $
  40  */
  41
  42 #ifdef TEST
  43 #undef perror
  44 #endif
  45
  46 #include <sys/types.h>
  47 #include <sys/ioctl.h>
  48 #include <sys/socket.h>
  49 #include <sys/sysctl.h>
  50 #include <sys/time.h>
  51 #include <net/if.h>
  52 #include <net/if_dl.h>
  53 #include <net/route.h>
  54 #include <netinet/in.h>
  55
  56 #include <errno.h>
  57 #include <netdb.h>
  58 #include <stdio.h>
  59 #include <stdlib.h>
  60 #include <string.h>
  61 #include <syslog.h>
  62 #include <unistd.h>
  63
  64 #include "pmap_check.h"
  65
  66 #ifndef TRUE
  67 #define TRUE    1
  68 #define FALSE   0
  69 #endif
  70
  71 #define ROUNDUP(x) ((x) ? (1 + (((x) - 1) | (sizeof(long) - 1))) : sizeof(long))
  72
  73 /* How many interfaces could there be on a computer? */
  74
  75 #define ESTIMATED_LOCAL 20
  76 static int num_local = -1;
  77 static struct in_addr *addrs;
  78
  79 static void
  80 rtiparse(struct ifa_msghdr *ifam, struct rt_addrinfo *ai)
  81 {
  82   char *wp;
  83   int rtax;
  84
  85   wp = (char *)(ifam + 1);
  86
  87   ai->rti_addrs = ifam->ifam_addrs;
  88   for (rtax = 0; rtax < sizeof ai->rti_info / sizeof *ai->rti_info; rtax++)
  89     if (ifam->ifam_addrs & (1 << rtax)) {
  90       ai->rti_info[rtax] = (struct sockaddr *)wp;
  91       wp += ROUNDUP(ai->rti_info[rtax]->sa_len);
  92     } else
  93       ai->rti_info[rtax] = NULL;
  94 }
  95
  96 /* find_local - find all IP addresses for this host */
  97
  98 static int
  99 find_local(void)
 100 {
 101   int mib[6], n, s, alloced;
 102   size_t needed;
 103   char *buf, *end, *ptr;
 104   struct if_msghdr *ifm;
 105   struct ifa_msghdr *ifam;
 106   struct rt_addrinfo ai;
 107   struct ifreq ifr;
 108   struct sockaddr_dl *dl;
 109
 110   mib[0] = CTL_NET;
 111   mib[1] = PF_ROUTE;
 112   mib[4] = NET_RT_IFLIST;
 113   mib[2] = mib[3] = mib[5] = 0;
 114
 115   if ((s = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
 116     perror("socket");
 117     return (0);
 118   }
 119   if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
 120     close(s);
 121     perror("sysctl(NET_RT_IFLIST)");
 122     return 0;
 123   }
 124   if ((buf = (char *)malloc(needed)) == NULL) {
 125     close(s);
 126     perror("malloc");
 127     return 0;
 128   }
 129   if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
 130     close(s);
 131     free(buf);
 132     perror("sysctl(NET_RT_IFLIST)(after malloc)");
 133     return 0;
 134   }
 135
 136   if (addrs) {
 137     free(addrs);
 138     addrs = NULL;
 139   }
 140   num_local = 0;
 141   alloced = 0;
 142   end = buf + needed;
 143
 144   for (ptr = buf; ptr < end; ptr += ifm->ifm_msglen) {
 145     ifm = (struct if_msghdr *)ptr;
 146     dl = (struct sockaddr_dl *)(ifm + 1);
 147
 148     if (ifm->ifm_index != dl->sdl_index || dl->sdl_nlen == 0)
 149       /* Skip over remaining ifa_msghdrs */
 150       continue;
 151
 152     n = dl->sdl_nlen > sizeof ifr.ifr_name ?
 153         sizeof ifr.ifr_name : dl->sdl_nlen;
 154     strncpy(ifr.ifr_name, dl->sdl_data, n);
 155     if (n < sizeof ifr.ifr_name)
 156       ifr.ifr_name[n] = '\0';
 157
 158     /* we only want the first address from each interface */
 159     if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0)
 160       fprintf(stderr, "%.*s: SIOCGIFFLAGS: %s\n", n, ifr.ifr_name,
 161               strerror(errno));
 162     else if (ifr.ifr_flags & IFF_UP) {    /* active interface */
 163       ifam = (struct ifa_msghdr *)(ptr + ifm->ifm_msglen);
 164       while ((char *)ifam < end && ifam->ifam_type == RTM_NEWADDR) {
 165         rtiparse(ifam, &ai);
 166
 167         if (ai.rti_info[RTAX_IFA] != NULL &&
 168             ai.rti_info[RTAX_IFA]->sa_family == AF_INET) {
 169           if (alloced < num_local + 1) {
 170             alloced += ESTIMATED_LOCAL;
 171             addrs = (struct in_addr *)realloc(addrs, alloced * sizeof addrs[0]);
 172             if (addrs == NULL) {
 173               perror("malloc/realloc");
 174               num_local = 0;
 175               break;
 176             }
 177           }
 178           addrs[num_local++] = ((struct sockaddr_in *)
 179             ai.rti_info[RTAX_IFA])->sin_addr;
 180
 181         }
 182         ifam = (struct ifa_msghdr *)((char *)ifam + ifam->ifam_msglen);
 183       }
 184     }
 185   }
 186   free(buf);
 187   close(s);
 188
 189   return num_local;
 190 }
 191
 192 /* from_local - determine whether request comes from the local system */
 193
 194 int
 195 from_local(struct sockaddr_in *addr)
 196 {
 197     int     i;
 198
 199     if (num_local == -1 && find_local() == 0)
 200         syslog(LOG_ERR, "cannot find any active local network interfaces");
 201
 202     for (i = 0; i < num_local; i++) {
 203         if (memcmp((char *) &(addr->sin_addr), (char *) &(addrs[i]),
 204                    sizeof(struct in_addr)) == 0)
 205             return (TRUE);
 206     }
 207     return (FALSE);
 208 }
 209
 210 #ifdef TEST
 211
 212 int
 213 main(int argc, char **argv)
 214 {
 215     char   *inet_ntoa();
 216     int     i;
 217
 218     find_local();
 219     for (i = 0; i < num_local; i++)
 220         printf("%s\n", inet_ntoa(addrs[i]));
 221
 222     return 0;
 223 }
 224
 225 #endif