--- net-tools-1.60/netstat.c.foo	Mon Apr 22 14:25:20 2002
+++ net-tools-1.60/netstat.c	Mon Apr 22 14:25:22 2002
@@ -435,6 +435,162 @@
 			 " will not be shown, you would have to be root to see it all.)\n"));
 }
 
+#define TCP_HASH_SIZE 1009
+
+static struct tcp_node {
+  struct tcp_node *next;
+  char            *socket_pair;
+} *tcp_node_hash[TCP_HASH_SIZE];
+
+static unsigned int tcp_node_compute_string_hash(const char *p)
+{
+  unsigned int h = *p;
+
+  if (h)
+    for (p += 1; *p != '\0'; p++)
+      h = (h << 5) - h + *p;
+
+  return h;
+}
+
+#define TCP_NODE_HASH_STRING(x) \
+  (tcp_node_compute_string_hash(x) % TCP_HASH_SIZE)
+
+static void tcp_node_hash_clear(void)
+{
+  int i;
+  struct tcp_node *next_node;
+  struct tcp_node *tmp_node;
+  for (i=0; i < TCP_HASH_SIZE; i++) {
+    if (tcp_node_hash[i]) {
+      /* free the children of this hash bucket */
+      next_node = tcp_node_hash[i]->next;
+      while (next_node) {
+	tmp_node = next_node;
+	next_node = next_node->next;
+	free(tmp_node->socket_pair);
+	free(tmp_node);
+      }
+
+      /* free the bucket itself */
+      free(tcp_node_hash[i]);
+      tcp_node_hash[i] = NULL;
+    }
+  }
+}
+
+/* This function takes a socket pair string.  If it already exists in
+   the hash it returns -1, otherwise it returns 0. */
+
+static int tcp_node_hash_check_and_append(const char *local_addr,
+					  int local_port,
+					  const char *rem_addr,
+					  int rem_port)
+{
+  unsigned int hash_val;
+  struct tcp_node *tmp_node;
+  int   tmp_string_len;
+  char *tmp_string;;
+
+  /* Size of the string is the size of the two lengths of the address
+     strings plus enough sizes for the colons and the ports. */
+  tmp_string_len = strlen(local_addr) + strlen(rem_addr) + 32;
+  tmp_string = malloc(tmp_string_len);
+  if (!tmp_string)
+    return 0;
+
+  if (snprintf(tmp_string, tmp_string_len - 1, "%s:%d:%s:%d",
+	       local_addr, local_port, rem_addr, rem_port) < 0) {
+    free(tmp_string);
+    return 0;
+  }
+
+  hash_val = TCP_NODE_HASH_STRING(tmp_string);
+
+  /* See if we have to allocate this node */
+  if (!tcp_node_hash[hash_val]) {
+    tcp_node_hash[hash_val] = malloc(sizeof(struct tcp_node));
+    if (!tcp_node_hash[hash_val]) {
+      free(tmp_string);
+      return 0;
+    }
+
+    memset(tcp_node_hash[hash_val], 0, sizeof(struct tcp_node));
+
+    /* Stuff this new value into the hash bucket and return early */
+    tcp_node_hash[hash_val]->socket_pair = tmp_string;
+    return 0;
+  }
+
+  /* Try to find the value in the hash bucket. */
+  tmp_node = tcp_node_hash[hash_val];
+  while (tmp_node) {
+    if (!strcmp(tmp_node->socket_pair, tmp_string)) {
+      free(tmp_string);
+      return -1;
+    }
+    tmp_node = tmp_node->next;
+  }
+
+  /* If we got this far it means that it isn't in the hash bucket.
+     Add it to the front since it's faster that way. */
+  tmp_node = tcp_node_hash[hash_val];
+
+  tcp_node_hash[hash_val] = malloc(sizeof(struct tcp_node));
+  if (!tcp_node_hash[hash_val]) {
+    free(tmp_string);
+    tcp_node_hash[hash_val] = tmp_node;
+    return 0;
+  }
+
+  tcp_node_hash[hash_val]->socket_pair = tmp_string;
+  tcp_node_hash[hash_val]->next = tmp_node;
+
+  return 0;
+}
+
+#if 0
+static void tcp_node_hash_report_bucket_size(void)
+{
+  int max = 0;
+  int min = 0;
+  int num = 0;
+  int total = 0;
+  struct tcp_node *tmp_node;
+  int tmp, i;
+  float avg;
+
+  for (i=0; i < TCP_HASH_SIZE; i++) {
+    tmp_node = tcp_node_hash[i];
+    if (!tmp_node)
+      continue;
+
+    tmp = 0;
+
+    num++;
+    tmp = 1;
+
+    while (tmp_node) {
+      tmp++;
+      tmp_node = tmp_node->next;
+    }
+    
+    total += tmp;
+    if (tmp > max)
+      max = tmp;
+    
+    if (min == 0 || tmp < min)
+      min = tmp;
+  }
+
+  avg = (float)total/(float)num;
+
+  printf("%d nodes in %d buckets min/max/avg %d/%d/%.2f\n",
+	 total, num, min, max, avg);
+
+}
+#endif
+
 #if HAVE_AFNETROM
 static const char *netrom_state[] =
 {
@@ -752,11 +908,20 @@
 	fprintf(stderr, _("warning, got bogus tcp line.\n"));
 	return;
     }
+
     if ((ap = get_afntype(((struct sockaddr *) &localaddr)->sa_family)) == NULL) {
 	fprintf(stderr, _("netstat: unsupported address family %d !\n"),
 		((struct sockaddr *) &localaddr)->sa_family);
 	return;
     }
+
+    /* make sure that we haven't seen this socket pair before */
+    if (tcp_node_hash_check_and_append(local_addr, local_port,
+				       rem_addr, rem_port) < 0) {
+      fprintf(stderr, _("warning, got duplicate tcp line.\n"));
+      return;
+    }
+
     if (state == TCP_LISTEN) {
 	time_len = 0;
 	retr = 0L;
@@ -1849,6 +2014,7 @@
 	    break;
 	sleep(1);
 	prg_cache_clear();
+	tcp_node_hash_clear();
     }
     return (i);
 }