--- webalizer.c.old	Mon Jun  7 20:43:06 1999
+++ webalizer.c	Wed Jun 16 11:42:53 1999
@@ -39,6 +39,16 @@
 #include <sys/utsname.h>
 #include <sys/times.h>
 
+/* needed for inverse lookup */
+
+#include <netdb.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <search.h>
+#include <setjmp.h>
+#include <signal.h>
+
 /* ensure getopt */
 #ifdef HAVE_GETOPT_H
 #include <getopt.h>
@@ -184,6 +194,11 @@
 NLISTPTR html_tail     = NULL;                /* tail HTML code           */
 NLISTPTR html_end      = NULL;                /* after everything else    */
 
+int reverse_lookup = 0;               /* enable reverse lookup of IP's */
+int dns_cache = 8192;		     /* size of the DNS hash table*/
+int dns_timeout = 2;		     /* DNS timout in seconds */
+jmp_buf jumper;                      /* need this to jump out the signal hanlder */
+
 /*********************************************/
 /* MAIN - start here                         */
 /*********************************************/
@@ -261,6 +276,11 @@
       }
    }
 
+   if(reverse_lookup)
+    {
+     hcreate(dns_cache);
+    }
+
    if (argc - optind != 0) log_fname = argv[optind];
 
    /* setup our internal variables */
@@ -1069,6 +1089,89 @@
    }
 }
 
+void lookup_host_name(char* host, int max_host_size)
+ {
+  struct in_addr in;
+  struct hostent *h;
+  static ENTRY e, *ep;
+  char* e_ip;
+  char* e_host = "";
+  int ip_len;
+  int host_len;
+
+  e.key = host;
+  ep = hsearch(e, FIND);
+  
+  if(debug_mode)
+   fprintf(stderr, "Looking up %s\n", e.key);
+  
+  if(ep)
+   {
+    if(debug_mode)
+     fprintf(stderr, "Found %s for %s in the DNS cache\n", ep->data, e.key);
+    
+    strncpy(host, ep->data, max_host_size);
+    return;
+   }
+
+  inet_aton(host, &in);
+ 
+  if(!setjmp(jumper))
+   {
+    signal(SIGALRM, lookup_sigalrm);
+    alarm(dns_timeout);
+    h = gethostbyaddr((char*)&in, sizeof(struct in_addr), AF_INET);
+    alarm(0);
+   }
+  else
+  {
+   if(verbose)
+    fprintf(stderr, "DNS request timed out for %s\n", e.key);
+   h = NULL;
+  }
+
+  e_ip = (char*)malloc(ip_len = strlen(host) + 1);
+  if(!e_ip)
+   {
+    fprintf(stderr, "Warning: malloc() failed in lookup_host_name()\n");
+    return;
+   }
+ 
+  memcpy(e_ip, host, ip_len);
+ 
+  if(h)
+   {
+    e_host = (char*)malloc(host_len = strlen(h->h_name) + 1);
+    if(!e_host)
+    {
+     fprintf(stderr, "Warning: malloc() failed in lookup_host_name()\n");
+     return;
+    }
+
+    memcpy(e_host, h->h_name, host_len );
+    memcpy(host, h->h_name, (max_host_size < host_len) ? 
+      max_host_size : (host_len + 1));
+   }
+  else
+   {
+    e_host = (char*)malloc(host_len = strlen(host) + 1);
+    if(!e_host)
+    {
+     fprintf(stderr, "Warning: malloc() failed in lookup_host_name()\n");
+     return;
+    }
+    memcpy(e_host, host, host_len);
+   }
+
+  e.key = e_ip;
+  e.data = e_host;
+  if(!hsearch(e, ENTER))
+   {
+    free(e_ip);
+    free(e_host);
+   }
+ }
+
 /*********************************************/
 /* PARSE_RECORD - uhhh, you know...          */
 /*********************************************/
@@ -1210,9 +1313,17 @@
    while ( (*cp1 != '\0') && (cp1 != eos) ) *cp2++ = *cp1++;
    *cp2 = '\0';
 
+   if(reverse_lookup)
+    lookup_host_name(log_rec.hostname, sizeof(log_rec.hostname));
+
    return 1;     /* maybe a valid record, return with TRUE */
 }
 
+void lookup_sigalrm()
+ {
+  longjmp(jumper, 1);
+ }
+
 void clear_month()
 {
    int i;
@@ -1284,8 +1395,11 @@
                      "IncludeSite",       /* Sites to always include    45  */
                      "IncludeURL",        /* URL's to always include    46  */
                      "IncludeReferrer",   /* Referrers to include       47  */
-                     "IncludeAgent"       /* User Agents to include     48  */
-                   };
+                     "IncludeAgent",       /* User Agents to include     48  */
+                     "ReverseLookup",	   /* Reverse Lookup of IPs     49 */
+                     "DNSCache",	   /* DNS cache size     50 */
+                     "DNSTimeout"	   /* DNS lookup timeout     51 */
+		   };
 
    FILE *fp;
 
@@ -1381,6 +1495,9 @@
         case 46: add_nlist(value,&include_urls);   break; /* IncludeURL     */
         case 47: add_nlist(value,&include_refs);   break;/*IncludeReferrer*/
         case 48: add_nlist(value,&include_agents); break; /* IncludeAgent   */
+	case 49: reverse_lookup = (value[0]=='y')?1:0; break; /* ReverseLookup */
+	case 50: dns_cache = atoi(value); break; /* ReverseLookup */
+	case 51: dns_timeout = atoi(value); break; /* ReverseLookup */
       }
    }
    fclose(fp);
--- webalizer.h.old	Mon Jun  7 21:10:10 1999
+++ webalizer.h	Wed Jun 16 11:42:57 1999
@@ -221,3 +221,6 @@
 void	top_ctry_table();                           /* top n countries ""  */
 static  char *save_opt(char *);                     /* save conf option    */
 u_long  ctry_idx(char *);                           /* index domain name   */
+
+void lookup_host_name(char* host, int max_host_size); /* inverse lookup of IPs */
+void lookup_sigalrm(); /* need this to time out long DNS lookups */