--- a/include/freeDiameter/libfdproto.h	Sun Mar 17 14:53:24 2013 +0100
+++ b/include/freeDiameter/libfdproto.h	Sun Mar 17 16:22:32 2013 +0100
@@ -2142,7 +2142,8 @@
 #define MSGFL_ALLOC_ETEID	0x01	/* When creating a message, a new end-to-end ID is allocated and set in the message */
 #define MSGFL_ANSW_ERROR	0x02	/* When creating an answer message, set the 'E' bit and use the generic error ABNF instead of command-specific ABNF */
 #define MSGFL_ANSW_NOSID	0x04	/* When creating an answer message, do not add the Session-Id even if present in request */
-#define MSGFL_MAX		MSGFL_ANSW_NOSID	/* The biggest valid flag value */
+#define MSGFL_ANSW_NOPROXYINFO	0x08	/* When creating an answer message, do not add the Proxy-Info AVPs presents in request */
+#define MSGFL_MAX		MSGFL_ANSW_NOPROXYINFO	/* The biggest valid flag value */
 
 /**************************************************/
 /*   Message creation, manipulation, disposal     */
@@ -2151,9 +2152,9 @@
  * FUNCTION:	fd_msg_avp_new
  *
  * PARAMETERS:
- *  model 	: Pointer to a DICT_AVP dictionary object describing the avp to create, or NULL.
- *  flags	: Flags to use in creation (AVPFL_*).
- *  avp 	: Upon success, pointer to the new avp is stored here.
+ *  model 	: Pointer to a DICT_AVP dictionary object describing the avp to create, or NULL if flags are used.
+ *  flags	: Flags to use in creation (AVPFL_*, see above).
+ *  avp 	: Upon success, pointer to the new avp is stored here. It points to reference AVP upon function call when flags are used.
  *
  * DESCRIPTION: 
  *   Create a new AVP instance.
@@ -2192,6 +2193,7 @@
  *  dict	: Pointer to the dictionary containing the model of the query.
  *  msg		: The location of the query on function call. Updated by the location of answer message on return.
  *  flag        : Pass MSGFL_ANSW_ERROR to indicate if the answer is an error message (will set the 'E' bit)
+ *              : See other MSGFL_ANSW_* definition above for other flags.
  *
  * DESCRIPTION: 
  *   This function creates the empty answer message corresponding to a request.

--- a/libfdproto/messages.c	Sun Mar 17 14:53:24 2013 +0100
+++ b/libfdproto/messages.c	Sun Mar 17 16:22:32 2013 +0100
@@ -300,6 +300,9 @@
 	return 0;
 }	
 
+static int bufferize_avp(unsigned char * buffer, size_t buflen, size_t * offset,  struct avp * avp);
+static int parsebuf_list(unsigned char * buf, size_t buflen, struct fd_list * head);
+
 /* Create answer from a request */
 int fd_msg_new_answer_from_req ( struct dictionary * dict, struct msg ** msg, int flags )
 {
@@ -359,6 +362,34 @@
 		CHECK_FCT( fd_sess_ref_msg(sess) );
 	}
 	
+	/* Add all Proxy-Info AVPs from the query if any */
+	if (! (flags & MSGFL_ANSW_NOPROXYINFO)) {
+		struct avp * avp;
+		CHECK_FCT(  fd_msg_browse(qry, MSG_BRW_FIRST_CHILD, &avp, NULL)  );
+		while (avp) {
+			if ( (avp->avp_public.avp_code   == AC_PROXY_INFO)
+			  && (avp->avp_public.avp_vendor == 0) ) {
+				/* We found a Proxy-Info, need to duplicate it in the answer */
+
+				/* In order to avoid dealing with all different possibilities of states, we just create a buffer then parse it */
+				unsigned char * buf = NULL;
+				size_t offset = 0;
+
+				CHECK_FCT(  fd_msg_update_length(avp)  );
+				CHECK_MALLOC(  buf = malloc(avp->avp_public.avp_len)  );
+				CHECK_FCT( bufferize_avp(buf, avp->avp_public.avp_len, &offset, avp)  );
+
+				/* Now we directly parse this buffer into the new message list */
+				CHECK_FCT( parsebuf_list(buf, avp->avp_public.avp_len, &ans->msg_chain.children) );
+
+				/* Done for this AVP */
+				free(buf);
+			}
+			/* move to next AVP in the message, we can have several Proxy-Info instances */
+			CHECK_FCT( fd_msg_browse(avp, MSG_BRW_NEXT, &avp, NULL) );
+		}
+	}
+
 	/* associate with query */
 	ans->msg_query = qry;
 	qry->msg_associated = 1;