diff -up dhcp-4.3.4/client/dhc6.c.sendDecline dhcp-4.3.4/client/dhc6.c

--- dhcp-4.3.4/client/dhc6.c.sendDecline	2016-03-22 14:16:51.000000000 +0100

+++ dhcp-4.3.4/client/dhc6.c	2016-05-02 14:51:57.916578401 +0200

@@ -115,6 +115,8 @@ void do_select6(void *input);

 void do_refresh6(void *input);

 static void do_release6(void *input);

 static void start_bound(struct client_state *client);

+static void start_decline6(struct client_state *client);

+static void do_decline6(void *input);

 static void start_informed(struct client_state *client);

 void informed_handler(struct packet *packet, struct client_state *client);

 void bound_handler(struct packet *packet, struct client_state *client);

@@ -2314,6 +2316,7 @@ start_release6(struct client_state *clie

 	cancel_timeout(do_select6, client);

 	cancel_timeout(do_refresh6, client);

 	cancel_timeout(do_release6, client);

+	cancel_timeout(do_decline6, client);

 	client->state = S_STOPPED;

 	/*

@@ -2968,6 +2971,7 @@ dhc6_check_reply(struct client_state *cl

 		break;

 	      case S_STOPPED:

+	      case S_DECLINED:

 		action = dhc6_stop_action;

 		break;

@@ -3084,6 +3088,7 @@ dhc6_check_reply(struct client_state *cl

 		break;

 	      case S_STOPPED:

+	      case S_DECLINED:

 		/* Nothing critical to do at this stage. */

 		break;

@@ -4214,17 +4219,23 @@ reply_handler(struct packet *packet, str

 	cancel_timeout(do_select6, client);

 	cancel_timeout(do_refresh6, client);

 	cancel_timeout(do_release6, client);

+	cancel_timeout(do_decline6, client);

 	/* If this is in response to a Release/Decline, clean up and return. */

-	if (client->state == S_STOPPED) {

-		if (client->active_lease == NULL)

-			return;

+	if ((client->state == S_STOPPED) ||

+	    (client->state == S_DECLINED)) {

+

+		if (client->active_lease != NULL) {

+			dhc6_lease_destroy(&client->active_lease, MDL);

+			client->active_lease = NULL;

+			/* We should never wait for nothing!? */

+			if (stopping_finished())

+				exit(0);

+		}

+

+		if (client->state == S_DECLINED)

+			start_init6(client);

-		dhc6_lease_destroy(&client->active_lease, MDL);

-		client->active_lease = NULL;

-		/* We should never wait for nothing!? */

-		if (stopping_finished())

-			exit(0);

 		return;

 	}

@@ -4798,7 +4809,11 @@ start_bound(struct client_state *client)

 			dhc6_marshall_values("new_", client, lease, ia, addr);

 			script_write_requested6(client);

-			script_go(client);

+			// when script returns 3, DAD failed

+			if (script_go(client) == 3) {

+				start_decline6(client);

+				return;

+			}

 		}

 		/* XXX: maybe we should loop on the old values instead? */

@@ -4851,6 +4866,149 @@ start_bound(struct client_state *client)

 	dhc6_check_times(client);

 }

+/*

+ * Decline addresses.

+ */

+void

+start_decline6(struct client_state *client)

+{

+	/* Cancel any pending transmissions */

+	cancel_timeout(do_confirm6, client);

+	cancel_timeout(do_select6, client);

+	cancel_timeout(do_refresh6, client);

+	cancel_timeout(do_release6, client);

+	cancel_timeout(do_decline6, client);

+	client->state = S_DECLINED;

+

+	if (client->active_lease == NULL)

+		return;

+

+	/* Set timers per RFC3315 section 18.1.7. */

+	client->IRT = DEC_TIMEOUT * 100;

+	client->MRT = 0;

+	client->MRC = DEC_MAX_RC;

+	client->MRD = 0;

+

+	dhc6_retrans_init(client);

+	client->v6_handler = reply_handler;

+

+	client->refresh_type = DHCPV6_DECLINE;

+	do_decline6(client);

+}

+

+/*

+ * do_decline6() creates a Decline packet and transmits it.

+ */

+static void

+do_decline6(void *input)

+{

+	struct client_state *client;

+	struct data_string ds;

+	struct timeval elapsed, tv;

+	int send_ret, added;

+

+	client = input;

+

+	if ((client->active_lease == NULL) || !active_prefix(client))

+		return;

+

+	if ((client->MRC != 0) && (client->txcount > client->MRC))  {

+		log_info("Max retransmission count exceeded.");

+		goto decline_done;

+	}

+

+	/*

+	 * Start_time starts at the first transmission.

+	 */

+	if (client->txcount == 0) {

+		client->start_time.tv_sec = cur_tv.tv_sec;

+		client->start_time.tv_usec = cur_tv.tv_usec;

+	}

+

+	/* elapsed = cur - start */

+	elapsed.tv_sec = cur_tv.tv_sec - client->start_time.tv_sec;

+	elapsed.tv_usec = cur_tv.tv_usec - client->start_time.tv_usec;

+	if (elapsed.tv_usec < 0) {

+		elapsed.tv_sec -= 1;

+		elapsed.tv_usec += 1000000;

+	}

+

+	memset(&ds, 0, sizeof(ds));

+	if (!buffer_allocate(&ds.buffer, 4, MDL)) {

+		log_error("Unable to allocate memory for Decline.");

+		goto decline_done;

+	}

+

+	ds.data = ds.buffer->data;

+	ds.len = 4;

+	ds.buffer->data[0] = DHCPV6_DECLINE;

+	memcpy(ds.buffer->data + 1, client->dhcpv6_transaction_id, 3);

+

+	/* Form an elapsed option. */

+	/* Maximum value is 65535 1/100s coded as 0xffff. */

+	if ((elapsed.tv_sec < 0) || (elapsed.tv_sec > 655) ||

+	    ((elapsed.tv_sec == 655) && (elapsed.tv_usec > 350000))) {

+		client->elapsed = 0xffff;

+	} else {

+		client->elapsed = elapsed.tv_sec * 100;

+		client->elapsed += elapsed.tv_usec / 10000;

+	}

+

+	client->elapsed = htons(client->elapsed);

+

+	log_debug("XMT: Forming Decline.");

+	make_client6_options(client, &client->sent_options,

+			     client->active_lease, DHCPV6_DECLINE);

+	dhcpv6_universe.encapsulate(&ds, NULL, NULL, client, NULL,

+				    client->sent_options, &global_scope,

+				    &dhcpv6_universe);

+

+	/* Append IA's (but don't release temporary addresses). */

+	if (wanted_ia_na &&

+	    dhc6_add_ia_na(client, &ds, client->active_lease,

+			   DHCPV6_DECLINE, 0, &added) != ISC_R_SUCCESS) {

+		data_string_forget(&ds, MDL);

+		goto decline_done;

+	}

+	if (wanted_ia_pd &&

+	    dhc6_add_ia_pd(client, &ds, client->active_lease,

+			   DHCPV6_DECLINE, 0, &added) != ISC_R_SUCCESS) {

+		data_string_forget(&ds, MDL);

+		goto decline_done;

+	}

+

+	/* Transmit and wait. */

+	log_info("XMT: Decline on %s, interval %ld0ms.",

+		 client->name ? client->name : client->interface->name,

+		 (long int)client->RT);

+

+	send_ret = send_packet6(client->interface, ds.data, ds.len,

+				&DHCPv6DestAddr);

+	if (send_ret != ds.len) {

+		log_error("dhc6: sendpacket6() sent %d of %d bytes",

+			  send_ret, ds.len);

+	}

+

+	data_string_forget(&ds, MDL);

+

+	/* Wait RT */

+	tv.tv_sec = cur_tv.tv_sec + client->RT / 100;

+	tv.tv_usec = cur_tv.tv_usec + (client->RT % 100) * 10000;

+	if (tv.tv_usec >= 1000000) {

+		tv.tv_sec += 1;

+		tv.tv_usec -= 1000000;

+	}

+	add_timeout(&tv, do_decline6, client, NULL, NULL);

+	dhc6_retrans_advance(client);

+	return;

+

+decline_done:

+	dhc6_lease_destroy(&client->active_lease, MDL);

+	client->active_lease = NULL;

+	start_init6(client);

+	return;

+}

+

 /* While bound, ignore packets.  In the future we'll want to answer

  * Reconfigure-Request messages and the like.

  */