cmdmon: allow client records to be reset

Add a flag to the CLIENT_ACCESSES_BY_INDEX request to reset the
NTP/cmdmon hits/dropped counters after reporting the current values.

Add -r option to the chronyc clients command to perform the reset. This
should make it easier to find clients that send large number of requests
over short periods of time.

candm.h

@@ -105,7 +105,8 @@
 #define REQ_NTP_SOURCE_NAME 65
 #define REQ_RESET_SOURCES 66
 #define REQ_AUTH_DATA 67
-#define N_REQUEST_TYPES 68
+#define REQ_CLIENT_ACCESSES_BY_INDEX3 68
+#define N_REQUEST_TYPES 69
 
 /* Structure used to exchange timespecs independent of time_t size */
 typedef struct {
@@ -321,6 +322,7 @@ typedef struct {
 typedef struct {
   uint32_t first_index;
   uint32_t n_clients;
+  uint32_t reset;
   int32_t EOR;
 } REQ_ClientAccessesByIndex;
 

client.c

@@ -1243,7 +1243,7 @@ give_help(void)
     "\0(e.g. Sep 25, 2015 16:30:05 or 16:30:05)\0"
     "\0\0NTP access:\0\0"
     "accheck <address>\0Check whether address is allowed\0"
-    "clients\0Report on clients that have accessed the server\0"
+    "clients [-r]\0Report on clients that have accessed the server\0"
     "serverstats\0Display statistics of the server\0"
     "allow [<subnet>]\0Allow access to subnet as a default\0"
     "allow all [<subnet>]\0Allow access to subnet and all children\0"
@@ -2673,18 +2673,27 @@ process_cmd_clients(char *line)
   CMD_Request request;
   CMD_Reply reply;
   IPAddr ip;
-  uint32_t i, n_clients, next_index, n_indices;
+  uint32_t i, n_clients, next_index, n_indices, reset;
   RPY_ClientAccesses_Client *client;
-  char name[50];
+  char name[50], *opt;
 
   next_index = 0;
+  reset = 0;
+
+  while (*line) {
+    opt = line;
+    line = CPS_SplitWord(line);
+    if (strcmp(opt, "-r") == 0)
+      reset = 1;
+  }
 
   print_header("Hostname                      NTP   Drop Int IntL Last     Cmd   Drop Int  Last");
 
   while (1) {
-    request.command = htons(REQ_CLIENT_ACCESSES_BY_INDEX2);
+    request.command = htons(REQ_CLIENT_ACCESSES_BY_INDEX3);
     request.data.client_accesses_by_index.first_index = htonl(next_index);
     request.data.client_accesses_by_index.n_clients = htonl(MAX_CLIENT_ACCESSES);
+    request.data.client_accesses_by_index.reset = htonl(reset);
 
     if (!request_reply(&request, &reply, RPY_CLIENT_ACCESSES_BY_INDEX2, 0))
       return 0;

clientlog.c

@@ -653,7 +653,8 @@ static uint32_t get_last_ago(uint32_t x, uint32_t y)
 /* ================================================== */
 
 int
-CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *report, struct timespec *now)
+CLG_GetClientAccessReportByIndex(int index, int reset,
+                                 RPT_ClientAccessByIndex_Report *report, struct timespec *now)
 {
   Record *record;
   uint32_t now_ts;
@@ -679,6 +680,11 @@ CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *repo
   report->last_ntp_hit_ago = get_last_ago(now_ts, record->last_ntp_hit);
   report->last_cmd_hit_ago = get_last_ago(now_ts, record->last_cmd_hit);
 
+  if (reset) {
+    record->ntp_hits = record->cmd_hits = 0;
+    record->ntp_drops = record->cmd_drops = 0;
+  }
+
   return 1;
 }
 

clientlog.h

@@ -44,7 +44,9 @@ extern int CLG_GetNtpMinPoll(void);
 /* And some reporting functions, for use by chronyc. */
 
 extern int CLG_GetNumberOfIndices(void);
-extern int CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *report, struct timespec *now);
+extern int CLG_GetClientAccessReportByIndex(int index, int reset,
+                                            RPT_ClientAccessByIndex_Report *report,
+                                            struct timespec *now);
 extern void CLG_GetServerStatsReport(RPT_ServerStatsReport *report);
 
 #endif /* GOT_CLIENTLOG_H */

cmdmon.c

@@ -137,6 +137,7 @@ static const char permissions[] = {
   PERMIT_OPEN, /* NTP_SOURCE_NAME */
   PERMIT_AUTH, /* RESET_SOURCES */
   PERMIT_AUTH, /* AUTH_DATA */
+  PERMIT_AUTH, /* CLIENT_ACCESSES_BY_INDEX3 */
 };
 
 /* ================================================== */
@@ -1001,7 +1002,7 @@ handle_client_accesses_by_index(CMD_Request *rx_message, CMD_Reply *tx_message)
   RPT_ClientAccessByIndex_Report report;
   RPY_ClientAccesses_Client *client;
   int n_indices;
-  uint32_t i, j, req_first_index, req_n_clients;
+  uint32_t i, j, req_first_index, req_n_clients, req_reset;
   struct timespec now;
 
   SCH_GetLastEventTime(&now, NULL, NULL);
@@ -1010,6 +1011,7 @@ handle_client_accesses_by_index(CMD_Request *rx_message, CMD_Reply *tx_message)
   req_n_clients = ntohl(rx_message->data.client_accesses_by_index.n_clients);
   if (req_n_clients > MAX_CLIENT_ACCESSES)
     req_n_clients = MAX_CLIENT_ACCESSES;
+  req_reset = ntohl(rx_message->data.client_accesses_by_index.reset);
 
   n_indices = CLG_GetNumberOfIndices();
   if (n_indices < 0) {
@@ -1021,7 +1023,7 @@ handle_client_accesses_by_index(CMD_Request *rx_message, CMD_Reply *tx_message)
   tx_message->data.client_accesses_by_index.n_indices = htonl(n_indices);
 
   for (i = req_first_index, j = 0; i < (uint32_t)n_indices && j < req_n_clients; i++) {
-    if (!CLG_GetClientAccessReportByIndex(i, &report, &now))
+    if (!CLG_GetClientAccessReportByIndex(i, req_reset, &report, &now))
       continue;
 
     client = &tx_message->data.client_accesses_by_index.clients[j++];
@@ -1594,7 +1596,7 @@ read_from_cmd_socket(int sock_fd, int event, void *anything)
           handle_cyclelogs(&rx_message, &tx_message);
           break;
 
-        case REQ_CLIENT_ACCESSES_BY_INDEX2:
+        case REQ_CLIENT_ACCESSES_BY_INDEX3:
           handle_client_accesses_by_index(&rx_message, &tx_message);
           break;
 

doc/chronyc.adoc

@@ -954,10 +954,13 @@ This command can be used to examine the effect of a series of *allow*, *allow
 all*, *deny*, and *deny all* commands specified either via *chronyc*, or in
 *chronyd*'s configuration file.
 
-[[clients]]*clients*::
+[[clients]]*clients* [*-r*]::
 This command shows a list of clients that have accessed the server, through
 either the NTP or command ports. It does not include accesses over
-the Unix domain command socket. There are no arguments.
+the Unix domain command socket.
++
+If the *-r* option is specified, *chronyd* will reset the counters of received
+and dropped packets after reporting the current values.
 +
 An example of the output is:
 +

pktlength.c

@@ -110,8 +110,7 @@ static const struct request_length request_lengths[] = {
   REQ_LENGTH_ENTRY(smoothtime, null),           /* SMOOTHTIME */
   REQ_LENGTH_ENTRY(null, null),                 /* REFRESH */
   REQ_LENGTH_ENTRY(null, server_stats),         /* SERVER_STATS */
-  REQ_LENGTH_ENTRY(client_accesses_by_index,
-                   client_accesses_by_index),   /* CLIENT_ACCESSES_BY_INDEX2 */
+  { 0, 0 },                                     /* CLIENT_ACCESSES_BY_INDEX2 - not supported */
   REQ_LENGTH_ENTRY(local, null),                /* LOCAL2 */
   REQ_LENGTH_ENTRY(ntp_data, ntp_data),         /* NTP_DATA */
   { 0, 0 },                                     /* ADD_SERVER2 */
@@ -125,6 +124,8 @@ static const struct request_length request_lengths[] = {
                    ntp_source_name),            /* NTP_SOURCE_NAME */
   REQ_LENGTH_ENTRY(null, null),                 /* RESET_SOURCES */
   REQ_LENGTH_ENTRY(auth_data, auth_data),       /* AUTH_DATA */
+  REQ_LENGTH_ENTRY(client_accesses_by_index,
+                   client_accesses_by_index),   /* CLIENT_ACCESSES_BY_INDEX3 */
 };
 
 static const uint16_t reply_lengths[] = {