release/src/router/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
  38 #include <sys/types.h>
  39 #include <sys/socket.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <netdb.h>
  43 #include <netinet/in.h>
  44 #include <net/if.h>
  45 #include <sys/ioctl.h>
  46 #include <syslog.h>
  47 #include <string.h>
  48 #include <unistd.h>
  49
  50 #ifndef TRUE
  51 #define TRUE    1
  52 #define FALSE   0
  53 #endif
  54
  55  /*
  56   * With virtual hosting, each hardware network interface can have multiple
  57   * network addresses. On such machines the number of machine addresses can
  58   * be surprisingly large.
  59   */
  60 static int num_local;
  61 static int num_addrs;
  62 static struct in_addr *addrs;
  63
  64 /* grow_addrs - extend list of local interface addresses */
  65
  66 static int grow_addrs(void)
  67 {
  68     struct in_addr *new_addrs;
  69     int     new_num;
  70
  71     /*
  72      * Keep the previous result if we run out of memory. The system would
  73      * really get hosed if we simply give up.
  74      */
  75     new_num = (addrs == 0) ? 1 : num_addrs + num_addrs;
  76     new_addrs = (struct in_addr *) malloc(sizeof(*addrs) * new_num);
  77     if (new_addrs == 0) {
  78         perror("portmap: out of memory");
  79         return (0);
  80     } else {
  81         if (addrs != 0) {
  82             memcpy((char *) new_addrs, (char *) addrs,
  83                    sizeof(*addrs) * num_addrs);
  84             free((char *) addrs);
  85         }
  86         num_addrs = new_num;
  87         addrs = new_addrs;
  88         return (1);
  89     }
  90 }
  91
  92 /* find_local - find all IP addresses for this host */
  93
  94 static int
  95 find_local(void)
  96 {
  97     struct ifconf ifc;
  98     struct ifreq ifreq;
  99     struct ifreq *ifr;
 100     struct ifreq *the_end;
 101     int     sock;
 102     char    buf[BUFSIZ];
 103
 104     /*
 105      * Get list of network interfaces. We use a huge buffer to allow for the
 106      * presence of non-IP interfaces.
 107      */
 108
 109     if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
 110         perror("socket");
 111         return (0);
 112     }
 113     ifc.ifc_len = sizeof(buf);
 114     ifc.ifc_buf = buf;
 115     if (ioctl(sock, SIOCGIFCONF, (char *) &ifc) < 0) {
 116         perror("SIOCGIFCONF");
 117         (void) close(sock);
 118         return (0);
 119     }
 120     /* Get IP address of each active IP network interface. */
 121
 122     the_end = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
 123     num_local = 0;
 124     for (ifr = ifc.ifc_req; ifr < the_end; ifr++) {
 125         if (ifr->ifr_addr.sa_family == AF_INET) {       /* IP net interface */
 126             ifreq = *ifr;
 127             if (ioctl(sock, SIOCGIFFLAGS, (char *) &ifreq) < 0) {
 128                 perror("SIOCGIFFLAGS");
 129             } else if (ifreq.ifr_flags & IFF_UP) {      /* active interface */
 130                 if (ioctl(sock, SIOCGIFADDR, (char *) &ifreq) < 0) {
 131                     perror("SIOCGIFADDR");
 132                 } else {
 133                     if (num_local >= num_addrs)
 134                         if (grow_addrs() == 0)
 135                             break;
 136                     addrs[num_local++] = ((struct sockaddr_in *)
 137                                           & ifreq.ifr_addr)->sin_addr;
 138                 }
 139             }
 140         }
 141         /* Support for variable-length addresses. */
 142 #ifdef HAS_SA_LEN
 143         ifr = (struct ifreq *) ((caddr_t) ifr
 144                       + ifr->ifr_addr.sa_len - sizeof(struct sockaddr));
 145 #endif
 146     }
 147     (void) close(sock);
 148     return (num_local);
 149 }
 150
 151 /* from_local - determine whether request comes from the local system */
 152
 153 int from_local(struct sockaddr_in *addr)
 154 {
 155     int     i;
 156
 157     if (addrs == 0 && find_local() == 0)
 158         syslog(LOG_ERR, "cannot find any active local network interfaces");
 159
 160     for (i = 0; i < num_local; i++) {
 161         if (memcmp((char *) &(addr->sin_addr), (char *) &(addrs[i]),
 162                    sizeof(struct in_addr)) == 0)
 163             return (TRUE);
 164     }
 165     return (FALSE);
 166 }
 167
 168 #ifdef TEST
 169
 170 main()
 171 {
 172     char   *inet_ntoa();
 173     int     i;
 174
 175     find_local();
 176     for (i = 0; i < num_local; i++)
 177         printf("%s\n", inet_ntoa(addrs[i]));
 178 }
 179
 180 #endif