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/*
* Check if an address belongs to the local system. Adapted from:
*
* @(#)pmap_svc.c 1.32 91/03/11 Copyright 1984,1990 Sun Microsystems, Inc.
* @(#)get_myaddress.c 2.1 88/07/29 4.0 RPCSRC.
*/
/*
* Sun RPC is a product of Sun Microsystems, Inc. and is provided for
* unrestricted use provided that this legend is included on all tape
* media and as a part of the software program in whole or part. Users
* may copy or modify Sun RPC without charge, but are not authorized
* to license or distribute it to anyone else except as part of a product or
* program developed by the user or with the express written consent of
* Sun Microsystems, Inc.
*
* SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
* WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
*
* Sun RPC is provided with no support and without any obligation on the
* part of Sun Microsystems, Inc. to assist in its use, correction,
* modification or enhancement.
*
* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
* OR ANY PART THEREOF.
*
* In no event will Sun Microsystems, Inc. be liable for any lost revenue
* or profits or other special, indirect and consequential damages, even if
* Sun has been advised of the possibility of such damages.
*
* Sun Microsystems, Inc.
* 2550 Garcia Avenue
* Mountain View, California 94043
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#) from_local.c 1.2 93/11/16 21:50:02";
#endif
static const char rcsid[] =
"$Id: from_local.c,v 1.6 1998/01/21 10:55:39 brian Exp $";
#endif
#ifdef TEST
#undef perror
#endif
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <netdb.h>
#include <stdlib.h>
#include <syslog.h>
#include <unistd.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif
/* How many interfaces could there be on a computer? */
#define ESTIMATED_LOCAL 20
static int num_local = -1;
static struct in_addr *addrs;
/* find_local - find all IP addresses for this host */
int
find_local()
{
int mib[6], n, s, alloced;
size_t needed;
char *buf, *end, *ptr;
struct if_msghdr *ifm;
struct ifreq ifr;
struct sockaddr_dl *dl;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[4] = NET_RT_IFLIST;
mib[2] = mib[3] = mib[5] = 0;
if ((s = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket");
return (0);
}
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
close(s);
perror("sysctl(NET_RT_IFLIST)");
return 0;
}
if ((buf = (char *)malloc(needed)) == NULL) {
close(s);
perror("malloc");
return 0;
}
if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
close(s);
free(buf);
perror("sysctl(NET_RT_IFLIST)(after malloc)");
return 0;
}
if (addrs) {
free(addrs);
addrs = NULL;
}
num_local = 0;
alloced = 0;
end = buf + needed;
for (ptr = buf; ptr < end; ptr += ifm->ifm_msglen) {
ifm = (struct if_msghdr *)ptr;
dl = (struct sockaddr_dl *)(ifm + 1);
n = dl->sdl_nlen > sizeof ifr.ifr_name ?
sizeof ifr.ifr_name : dl->sdl_nlen;
if (n == 0)
continue;
strncpy(ifr.ifr_name, dl->sdl_data, n);
if (n < sizeof ifr.ifr_name)
ifr.ifr_name[n] = '\0';
/* we only want the first address from each interface */
if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0)
perror("SIOCGIFFLAGS");
else if (ifr.ifr_flags & IFF_UP) /* active interface */
if (ioctl(s, SIOCGIFADDR, &ifr) < 0)
perror("SIOCGIFADDR");
else {
if (alloced < num_local + 1) {
alloced += ESTIMATED_LOCAL;
if (addrs)
addrs = (struct in_addr *)realloc(addrs, alloced * sizeof addrs[0]);
else
addrs = (struct in_addr *)malloc(alloced * sizeof addrs[0]);
if (addrs == NULL) {
perror("malloc/realloc");
num_local = 0;
break;
}
}
addrs[num_local++] = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr;
}
}
free(buf);
close(s);
return num_local;
}
/* from_local - determine whether request comes from the local system */
int
from_local(addr)
struct sockaddr_in *addr;
{
int i;
if (num_local == -1 && find_local() == 0)
syslog(LOG_ERR, "cannot find any active local network interfaces");
for (i = 0; i < num_local; i++) {
if (memcmp((char *) &(addr->sin_addr), (char *) &(addrs[i]),
sizeof(struct in_addr)) == 0)
return (TRUE);
}
return (FALSE);
}
#ifdef TEST
main()
{
char *inet_ntoa();
int i;
find_local();
for (i = 0; i < num_local; i++)
printf("%s\n", inet_ntoa(addrs[i]));
}
#endif
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