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Don't assume that a computer can have no more than

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256 interfaces (mine doesn't).  Instead, find local
interface addresses using sysctl().
This commit is contained in:
Brian Somers 1998-01-21 10:55:39 +00:00
parent f1f68c89d6
commit 217e186518
1 changed files with 79 additions and 46 deletions
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125
usr.sbin/portmap/from_local.c
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@ -40,7 +40,7 @@
static char sccsid[] = "@(#) from_local.c 1.2 93/11/16 21:50:02";
#endif
static const char rcsid[] =
"$Id$";
"$Id: from_local.c,v 1.5 1997/10/09 07:17:09 charnier Exp $";
#endif
#ifdef TEST
@ -50,6 +50,7 @@ static const char rcsid[] =
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <netdb.h>
@ -57,6 +58,7 @@ static const char rcsid[] =
#include <unistd.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#ifndef TRUE
@ -66,61 +68,92 @@ static const char rcsid[] =
/* How many interfaces could there be on a computer? */
#define MAX_LOCAL 256 /* overkill */
#define ESTIMATED_LOCAL 20
static int num_local = -1;
static struct in_addr addrs[MAX_LOCAL];
static struct in_addr *addrs;
/* find_local - find all IP addresses for this host */
int
find_local()
{
struct ifconf ifc;
struct ifreq ifreq;
struct ifreq *ifr;
struct ifreq *the_end;
int sock;
char buf[MAX_LOCAL * sizeof(struct ifreq)];
int mib[6], n, s, alloced;
size_t needed;
char *buf, *end, *ptr;
struct if_msghdr *ifm;
struct ifreq ifr;
struct sockaddr_dl *dl;
/* Get list of network interfaces. */
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[4] = NET_RT_IFLIST;
mib[2] = mib[3] = mib[5] = 0;
if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket");
return (0);
}
ifc.ifc_len = sizeof(buf);
ifc.ifc_buf = buf;
if (ioctl(sock, SIOCGIFCONF, (char *) &ifc) < 0) {
perror("SIOCGIFCONF");
(void) close(sock);
return (0);
}
/* Get IP address of each active IP network interface. */
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;
}
the_end = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
num_local = 0;
for (ifr = ifc.ifc_req; ifr < the_end; ifr++) {
if (ifr->ifr_addr.sa_family == AF_INET) { /* IP net interface */
ifreq = *ifr;
if (ioctl(sock, SIOCGIFFLAGS, (char *) &ifreq) < 0) {
perror("SIOCGIFFLAGS");
} else if (ifreq.ifr_flags & IFF_UP) { /* active interface */
if (ioctl(sock, SIOCGIFADDR, (char *) &ifreq) < 0) {
perror("SIOCGIFADDR");
} else {
addrs[num_local++] = ((struct sockaddr_in *)
& ifreq.ifr_addr)->sin_addr;
}
}
}
if (num_local >= MAX_LOCAL)
break;
/* Support for variable-length addresses. */
ifr = (struct ifreq *) ((caddr_t) ifr
+ ifr->ifr_addr.sa_len - sizeof(struct sockaddr));
}
(void) close(sock);
return (num_local);
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 */