diff --git a/libfdcore/p_dw.c b/libfdcore/p_dw.c
new file mode 100644
index 0000000..dc87f8d
--- /dev/null
+++ b/libfdcore/p_dw.c
@@ -0,0 +1,177 @@
+/*********************************************************************************************************
+* Software License Agreement (BSD License)                                                               *
+* Author: Sebastien Decugis <sdecugis@freediameter.net>							 *
+*													 *
+* Copyright (c) 2013, WIDE Project and NICT								 *
+* All rights reserved.											 *
+* 													 *
+* Redistribution and use of this software in source and binary forms, with or without modification, are  *
+* permitted provided that the following conditions are met:						 *
+* 													 *
+* * Redistributions of source code must retain the above 						 *
+*   copyright notice, this list of conditions and the 							 *
+*   following disclaimer.										 *
+*    													 *
+* * Redistributions in binary form must reproduce the above 						 *
+*   copyright notice, this list of conditions and the 							 *
+*   following disclaimer in the documentation and/or other						 *
+*   materials provided with the distribution.								 *
+* 													 *
+* * Neither the name of the WIDE Project or NICT nor the 						 *
+*   names of its contributors may be used to endorse or 						 *
+*   promote products derived from this software without 						 *
+*   specific prior written permission of WIDE Project and 						 *
+*   NICT.												 *
+* 													 *
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED *
+* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A *
+* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR *
+* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 	 *
+* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 	 *
+* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR *
+* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF   *
+* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.								 *
+*********************************************************************************************************/
+
+#include "fdcore-internal.h"
+
+/* This file contains code to handle Device Watchdog messages (DWR and DWA) */
+
+/* Check the value of Origin-State-Id is consistent in a DWR or DWA -- we return an error otherwise */
+static int check_state_id(struct msg * msg, struct fd_peer * peer)
+{
+	struct avp * osi;
+	
+	/* Check if the request contains the Origin-State-Id */
+	CHECK_FCT( fd_msg_search_avp ( msg, fd_dict_avp_OSI, &osi ) );
+	if (osi) {
+		/* Check the value is consistent with the saved one */
+		struct avp_hdr * hdr;
+		CHECK_FCT(  fd_msg_avp_hdr( osi, &hdr )  );
+		if (hdr->avp_value == NULL) {
+			/* This is a sanity check */
+			LOG_F("Ignored an Origin-State-Id AVP with unset value in DWR/DWA");
+			ASSERT(0); /* To check if this really happens, and understand why... */
+		}
+
+		if (! peer->p_hdr.info.runtime.pir_orstate) {
+			/* It was not already received in CER/CEA, save it now */
+			peer->p_hdr.info.runtime.pir_orstate = hdr->avp_value->u32;
+		}
+
+		if (peer->p_hdr.info.runtime.pir_orstate != hdr->avp_value->u32) {
+			TRACE_DEBUG(INFO, "Received a new Origin-State-Id from peer '%s'! (%x -> %x); resetting the connection.", 
+				peer->p_hdr.info.pi_diamid, 
+				peer->p_hdr.info.runtime.pir_orstate,
+				hdr->avp_value->u32 );
+			return EINVAL;
+		}
+	}
+	return 0;
+}
+
+/* Create and send a DWR */
+static int send_DWR(struct fd_peer * peer)
+{
+	struct msg * msg = NULL;
+	
+	/* Create a new DWR instance */
+	CHECK_FCT( fd_msg_new ( fd_dict_cmd_DWR, MSGFL_ALLOC_ETEID, &msg ) );
+	
+	/* Add the content of the message (only the origin) */
+	CHECK_FCT( fd_msg_add_origin ( msg, 1 ) );
+	
+	/* Now send this message */
+	CHECK_FCT( fd_out_send(&msg, NULL, peer, 0) );
+	
+	/* And mark the pending DW */
+	peer->p_flags.pf_dw_pending = 1;
+	
+	return 0;
+}
+
+/* Handle an incoming message */
+int fd_p_dw_handle(struct msg ** msg, int req, struct fd_peer * peer)
+{
+	int reset_tmr = 0;
+	
+	TRACE_ENTRY("%p %d %p", msg, req, peer);
+	
+	/* Check the value of OSI for information */
+	CHECK_FCT( check_state_id(*msg, peer) );
+	
+	if (req) {
+		/* If we receive a DWR, send back a DWA */
+		CHECK_FCT( fd_msg_new_answer_from_req ( fd_g_config->cnf_dict, msg, 0 ) );
+		CHECK_FCT( fd_msg_rescode_set( *msg, "DIAMETER_SUCCESS", NULL, NULL, 0 ) );
+		CHECK_FCT( fd_msg_add_origin ( *msg, 1 ) );
+		CHECK_FCT( fd_out_send( msg, peer->p_cnxctx, peer, 0) );
+		
+	} else {
+		/* Discard the DWA */
+		CHECK_FCT_DO( fd_msg_free(*msg), /* continue */ );
+		*msg = NULL;
+		
+		/* And clear the pending DW flag */
+		peer->p_flags.pf_dw_pending = 0;
+	}
+	
+	/* Now update timeout */
+	if (req) {
+		/* Update timeout only if we did not already send a DWR ourselves */
+		reset_tmr = !peer->p_flags.pf_dw_pending;
+	} else {
+		/* Reset the timer */
+		reset_tmr = 1;
+	}
+	if (reset_tmr) {
+		fd_psm_next_timeout(peer, 1, peer->p_hdr.info.config.pic_twtimer ?: fd_g_config->cnf_timer_tw);
+	}
+	
+	/* If we are in REOPEN state, increment the counter */
+	if (fd_peer_getstate(peer) == STATE_REOPEN) {
+		peer->p_flags.pf_reopen_cnt += 1;
+		
+		if (peer->p_flags.pf_reopen_cnt) {
+			/* Send a new DWR */
+			CHECK_FCT( send_DWR(peer) );
+		} else {
+			/* Move to OPEN state */
+			CHECK_FCT( fd_psm_change_state(peer, STATE_OPEN) );
+		}
+	}
+		
+	return 0;
+}
+
+/* Handle a timeout in the PSM (OPEN or REOPEN state only) */
+int fd_p_dw_timeout(struct fd_peer * peer)
+{
+	TRACE_ENTRY("%p", peer);
+
+	if (peer->p_flags.pf_dw_pending) {
+		/* We have sent a DWR and received no answer during TwTimer */
+		CHECK_FCT( fd_psm_change_state(peer, STATE_SUSPECT) );
+		fd_psm_next_timeout(peer, 0, 2 * (peer->p_hdr.info.config.pic_twtimer ?: fd_g_config->cnf_timer_tw) );
+	} else {
+		/* The timeout has expired, send a DWR */
+		CHECK_FCT( send_DWR(peer) );
+		fd_psm_next_timeout(peer, 0, peer->p_hdr.info.config.pic_twtimer ?: fd_g_config->cnf_timer_tw );
+	}
+	
+	return 0;
+}
+
+/* Handle DW exchanges after the peer has come alive again */
+int fd_p_dw_reopen(struct fd_peer * peer)
+{
+	TRACE_ENTRY("%p", peer);
+
+	peer->p_flags.pf_reopen_cnt = 1;
+	peer->p_flags.pf_cnx_pb = 0;
+	CHECK_FCT( send_DWR(peer) );
+	
+	return 0;
+}
+
+