2000-08-25 H.J. Lu <hjl@lucon.org>

[nfs-utils.git] / support / misc / from_local.c

diff --git a/support/misc/from_local.c b/support/misc/from_local.c
new file mode 100644 (file)
index 0000000..56478d7
--- /dev/null
+++ b/support/misc/from_local.c
@@ -0,0 +1,188 @@
+ /*
+  * 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
+static char sccsid[] = "@(#) from_local.c 1.3 96/05/31 15:52:57";
+#endif
+
+#ifdef TEST
+#undef perror
+#endif
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <syslog.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef TRUE
+#define        TRUE    1
+#define FALSE  0
+#endif
+
+ /*
+  * With virtual hosting, each hardware network interface can have multiple
+  * network addresses. On such machines the number of machine addresses can
+  * be surprisingly large.
+  */
+static int num_local;
+static int num_addrs;
+static struct in_addr *addrs;
+
+/* grow_addrs - extend list of local interface addresses */
+
+static int grow_addrs()
+{
+    struct in_addr *new_addrs;
+    int     new_num;
+
+    /*
+     * Keep the previous result if we run out of memory. The system would
+     * really get hosed if we simply give up.
+     */
+    new_num = (addrs == 0) ? 1 : num_addrs + num_addrs;
+    new_addrs = (struct in_addr *) malloc(sizeof(*addrs) * new_num);
+    if (new_addrs == 0) {
+       perror("portmap: out of memory");
+       return (0);
+    } else {
+       if (addrs != 0) {
+           memcpy((char *) new_addrs, (char *) addrs,
+                  sizeof(*addrs) * num_addrs);
+           free((char *) addrs);
+       }
+       num_addrs = new_num;
+       addrs = new_addrs;
+       return (1);
+    }
+}
+
+/* find_local - find all IP addresses for this host */
+static int
+find_local()
+{
+    struct ifconf ifc;
+    struct ifreq ifreq;
+    struct ifreq *ifr;
+    struct ifreq *the_end;
+    int     sock;
+    char    buf[BUFSIZ];
+
+    /*
+     * Get list of network interfaces. We use a huge buffer to allow for the
+     * presence of non-IP interfaces.
+     */
+
+    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. */
+
+    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 {
+                   if (num_local >= num_addrs)
+                       if (grow_addrs() == 0)
+                           break;
+                   addrs[num_local++] = ((struct sockaddr_in *)
+                                         & ifreq.ifr_addr)->sin_addr;
+               }
+           }
+       }
+       /* Support for variable-length addresses. */
+#ifdef HAS_SA_LEN
+       ifr = (struct ifreq *) ((caddr_t) ifr
+                     + ifr->ifr_addr.sa_len - sizeof(struct sockaddr));
+#endif
+    }
+    (void) close(sock);
+    return (num_local);
+}
+
+/* from_local - determine whether request comes from the local system */
+int
+from_local(addr)
+struct sockaddr_in *addr;
+{
+    int     i;
+
+    if (addrs == 0 && 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