--- freeradius-server-2.0.4/src/modules/rlm_ippool/rlm_ippool.c	2008-01-06 18:27:41.000000000 +0100
+++ freeradius-server-2.0.4/src/modules/rlm_ippool/rlm_ippool.c	2008-11-18 11:32:08.000000000 +0100
@@ -53,6 +53,10 @@
  * - If Pool-Name is set to DEFAULT then always run.
  * Mar 2005, Kostas Kalevras <kkalev@noc.ntua.gr>
  * - Make the key an MD5 of a configurable xlated string. This closes Bug #42
+ * Jul 2006, Sebastien Cantos <s.cantos@neopost.com>
+ * - Add a retention parameter that allows to make sure an IP is kept used in the pool for a certain
+ *   amount of time before being avalaible in the pool. This solves a problem dealing with TCP
+ *   TIME_WAIT state when an IP is assigned to a client just after being released.
  */
 
 #include <freeradius-devel/ident.h>
@@ -98,6 +102,7 @@
 	uint32_t range_stop;
 	uint32_t netmask;
 	time_t max_timeout;
+	time_t ret_time;
 	int cache_size;
 	int override;
 	GDBM_FILE gdbm;
@@ -149,6 +154,7 @@
   { "cache-size", PW_TYPE_INTEGER, offsetof(rlm_ippool_t,cache_size), NULL, "1000" },
   { "override", PW_TYPE_BOOLEAN, offsetof(rlm_ippool_t,override), NULL, "no" },
   { "maximum-timeout", PW_TYPE_INTEGER, offsetof(rlm_ippool_t,max_timeout), NULL, "0" },
+  { "retention-time", PW_TYPE_INTEGER, offsetof(rlm_ippool_t,ret_time), NULL, "0" },
   { NULL, -1, 0, NULL, NULL }
 };
 
@@ -363,13 +369,20 @@
 
 		/*
 		 * If the entry was found set active to zero
+		 * or keep it active during retention time
 		 */
 		memcpy(&entry, data_datum.dptr, sizeof(ippool_info));
 		free(data_datum.dptr);
 		DEBUG("rlm_ippool: Deallocated entry for ip: %s",ip_ntoa(str,entry.ipaddr));
-		entry.active = 0;
-		entry.timestamp = 0;
-		entry.timeout = 0;
+		if (data->ret_time > 0) {
+			DEBUG("rlm_ippool: Entry will be kept active during retention time: %d seconds",data->ret_time);
+			entry.timestamp = request->timestamp;
+			entry.timeout = data->ret_time;
+		} else {
+			entry.active = 0;
+			entry.timestamp = 0;
+			entry.timeout = 0;
+		}
 
 		/*
 		 * Save the reference to the entry