Add RTT calculation for DHCP Time calculation

Calculate the RTT of DHCP requests and report in address callback

When receiving DHCP Time vendor data use RTT value to estimate the error
Take RTT into account when setting the time

nanostack/dhcp_service_api.h

@@ -226,6 +226,16 @@ void dhcp_service_set_retry_timers(uint32_t msg_tr_id, uint16_t timeout_init, ui
  */
 void dhcp_service_update_server_address(uint32_t msg_tr_id, uint8_t *server_address);
 
+/**
+ * \brief Get Round Trip time of the request
+ *
+ * get the elapsed time of the request from last message sent to server.
+ *
+ * \param msg_tr_id The message transaction ID.
+ *
+ */
+uint32_t dhcp_service_rtt_get(uint32_t msg_tr_id);
+
 /**
  * \brief Stops transactions for a message (retransmissions).
  *

source/6LoWPAN/ws/ws_bootstrap.c

@@ -1010,11 +1010,18 @@ static void ws_bootstrap_dhcp_info_notify_cb(int8_t interface, dhcp_option_notif
                     int32_t era;
                     uint32_t offset;
                     if (net_vendor_option_current_time_read(options->option.vendor_spesific.data, options->option.vendor_spesific.data_length, &era, &offset, NULL)) {
-                        uint32_t estimated_error = 10;
                         uint64_t current_time;
                         uint64_t network_time = (era * (uint64_t)(4294967296)) + offset - 2208988800; //Convert to First day of Unix (1 Jan 1970)
+
+                        tr_debug("Network Time option Era:%"PRId32" Offset:%"PRIu32" rtt: %"PRId32" time: %"PRIu64,  era, offset, server_info->rtt, network_time);
                         if (0 == ns_time_system_time_read(&current_time)) {
                             uint64_t difference;
+                            // We only adjust clock if time has drifted more than 10 seconds to avoid constant changing of time
+                            // If Round trip time is very high the accuracy is reduced.
+                            uint32_t estimated_error = 10 + server_info->rtt / 10;
+                            // Take into account the round trip time it took the response to arrive from the time server Write the time.
+                            network_time += server_info->rtt / 20;
+
                             if (current_time > network_time) {
                                 difference = current_time - network_time;
                             } else {

source/DHCPv6_client/dhcpv6_client_api.h

@@ -84,6 +84,7 @@ typedef struct dhcp_server_notify_info {
     uint16_t duid_type;
     uint16_t duid_length;
     uint32_t life_time;
+    uint32_t rtt; // Round trip time with 100ms tics.
     uint8_t *duid;
 } dhcp_server_notify_info_t;
 

source/DHCPv6_client/dhcpv6_client_service.c

@@ -241,7 +241,7 @@ void dhcpv6_client_send_error_cb(dhcpv6_client_server_data_t *srv_data_ptr)
 }
 
 
-static void dhcp_vendor_information_notify(uint8_t *ptr, uint16_t data_len, dhcp_client_class_t *dhcp_client, dhcpv6_client_server_data_t *srv_data_ptr)
+static void dhcp_vendor_information_notify(uint8_t *ptr, uint16_t data_len, dhcp_client_class_t *dhcp_client, dhcpv6_client_server_data_t *srv_data_ptr, uint32_t message_rtt)
 {
     if (!dhcp_client->option_information_cb) {
         return;
@@ -261,6 +261,8 @@ static void dhcp_vendor_information_notify(uint8_t *ptr, uint16_t data_len, dhcp
     server_info.duid = srv_data_ptr->serverDUID.duid + 2; // Skip the type
     server_info.duid_type = srv_data_ptr->serverDUID.type;
     server_info.duid_length = srv_data_ptr->serverDUID.duid_length - 2;// remove the type
+    server_info.rtt = message_rtt;
+
 
     while (data_len >= 4) {
         type = common_read_16_bit(ptr);
@@ -309,6 +311,7 @@ int dhcp_solicit_resp_cb(uint16_t instance_id, void *ptr, uint8_t msg_name,  uin
     dhcp_duid_options_params_t clientId;
     dhcp_duid_options_params_t serverId;
     dhcpv6_client_server_data_t *srv_data_ptr = NULL;
+    uint32_t message_rtt;
     (void)instance_id;
 
     //Validate that started TR ID class is still at list
@@ -327,6 +330,8 @@ int dhcp_solicit_resp_cb(uint16_t instance_id, void *ptr, uint8_t msg_name,  uin
     }
 
 
+    message_rtt = dhcp_service_rtt_get(srv_data_ptr->transActionId);
+
     //Clear Active Transaction state
     srv_data_ptr->transActionId = 0;
 
@@ -399,7 +404,7 @@ int dhcp_solicit_resp_cb(uint16_t instance_id, void *ptr, uint8_t msg_name,  uin
     }
 
     //Optional Options notify from Reply
-    dhcp_vendor_information_notify(msg_ptr, msg_len, dhcp_client, srv_data_ptr);
+    dhcp_vendor_information_notify(msg_ptr, msg_len, dhcp_client, srv_data_ptr, message_rtt);
 
     return RET_MSG_ACCEPTED;
 error_exit:

source/libDHCPv6/dhcp_service_api.c

@@ -75,6 +75,7 @@ typedef struct {
     void  *client_obj_ptr;
     uint32_t msg_tr_id;
     uint32_t message_tr_id;
+    uint32_t transmit_time;
     uint32_t first_transmit_time;
     uint16_t delayed_tx;
     uint16_t timeout;
@@ -795,6 +796,7 @@ uint32_t dhcp_service_send_req(uint16_t instance_id, uint8_t options, void *ptr,
     msg_tr_ptr->recv_resp_cb = receive_resp_cb;
     msg_tr_ptr->delayed_tx = delay_tx;
     msg_tr_ptr->first_transmit_time = 0;
+    msg_tr_ptr->transmit_time = 0;
     dhcp_tr_set_retry_timers(msg_tr_ptr, msg_tr_ptr->msg_ptr[0]);
     common_write_24_bit(msg_tr_ptr->msg_tr_id, &msg_tr_ptr->msg_ptr[1]);
 
@@ -826,6 +828,16 @@ void dhcp_service_update_server_address(uint32_t msg_tr_id, uint8_t *server_addr
     }
 }
 
+uint32_t dhcp_service_rtt_get(uint32_t msg_tr_id)
+{
+    msg_tr_t *msg_tr_ptr = dhcp_tr_find(msg_tr_id);
+
+    if (msg_tr_ptr && msg_tr_ptr->transmit_time) {
+        return protocol_core_monotonic_time - msg_tr_ptr->transmit_time;
+    }
+    return 0;
+}
+
 void dhcp_service_req_remove(uint32_t msg_tr_id)
 {
     if (dhcp_service) {
@@ -927,6 +939,7 @@ void dhcp_service_send_message(msg_tr_t *msg_tr_ptr)
             int16_t tc = 0;
             socket_setsockopt(msg_tr_ptr->socket, SOCKET_IPPROTO_IPV6, SOCKET_IPV6_TCLASS, &tc, sizeof(tc));
             retval = socket_sendto(msg_tr_ptr->socket, &msg_tr_ptr->addr, msg_tr_ptr->msg_ptr, msg_tr_ptr->msg_len);
+            msg_tr_ptr->transmit_time = protocol_core_monotonic_time ? protocol_core_monotonic_time : 1;
             if (msg_tr_ptr->first_transmit_time == 0 && retval == 0) {
                 //Mark first pushed message timestamp
                 msg_tr_ptr->first_transmit_time = protocol_core_monotonic_time ? protocol_core_monotonic_time : 1;

test/nanostack/unittest/stub/dhcp_service_api_stub.c

@@ -155,6 +155,10 @@ uint32_t dhcp_service_send_req(uint16_t instance_id, uint8_t options, void *ptr,
 void dhcp_service_set_retry_timers(uint32_t msg_tr_id, uint16_t timeout_init, uint16_t timeout_max, uint8_t retrans_max)
 {
 }
+uint32_t dhcp_service_rtt_get(uint32_t msg_tr_id)
+{
+    return 0;
+}
 
 void dhcp_service_req_remove(uint32_t msg_tr_id)
 {