cmdmon: add request to get source name

Specify a new request to get the name of the NTP source corresponding to
an address, which was originally specified in the configuration file or
chronyc add command.

candm.h

@@ -102,7 +102,8 @@
 #define REQ_SHUTDOWN 62
 #define REQ_ONOFFLINE 63
 #define REQ_ADD_SOURCE 64
-#define N_REQUEST_TYPES 65
+#define REQ_NTP_SOURCE_NAME 65
+#define N_REQUEST_TYPES 66
 
 /* Structure used to exchange timespecs independent of time_t size */
 typedef struct {
@@ -342,6 +343,11 @@ typedef struct {
   int32_t EOR;
 } REQ_NTPData;
 
+typedef struct {
+  IPAddr ip_addr;
+  int32_t EOR;
+} REQ_NTPSourceName;
+
 /* ================================================== */
 
 #define PKT_TYPE_CMD_REQUEST 1
@@ -444,6 +450,7 @@ typedef struct {
     REQ_ReselectDistance reselect_distance;
     REQ_SmoothTime smoothtime;
     REQ_NTPData ntp_data;
+    REQ_NTPData ntp_source_name;
   } data; /* Command specific parameters */
 
   /* Padding used to prevent traffic amplification.  It only defines the
@@ -480,7 +487,8 @@ typedef struct {
 #define RPY_NTP_DATA 16
 #define RPY_MANUAL_TIMESTAMP2 17
 #define RPY_MANUAL_LIST2 18
-#define N_REPLY_TYPES 19
+#define RPY_NTP_SOURCE_NAME 19
+#define N_REPLY_TYPES 20
 
 /* Status codes */
 #define STT_SUCCESS 0
@@ -696,6 +704,11 @@ typedef struct {
   int32_t EOR;
 } RPY_NTPData;
 
+typedef struct {
+  int8_t name[256];
+  int32_t EOR;
+} RPY_NTPSourceName;
+
 typedef struct {
   uint8_t version;
   uint8_t pkt_type;
@@ -725,6 +738,7 @@ typedef struct {
     RPY_Activity activity;
     RPY_Smoothing smoothing;
     RPY_NTPData ntp_data;
+    RPY_NTPSourceName ntp_source_name;
   } data; /* Reply specific parameters */
 
 } CMD_Reply;

cmdmon.c

@@ -133,6 +133,7 @@ static const char permissions[] = {
   PERMIT_AUTH, /* SHUTDOWN */
   PERMIT_AUTH, /* ONOFFLINE */
   PERMIT_AUTH, /* ADD_SOURCE */
+  PERMIT_OPEN, /* NTP_SOURCE_NAME */
 };
 
 /* ================================================== */
@@ -1188,6 +1189,33 @@ handle_shutdown(CMD_Request *rx_message, CMD_Reply *tx_message)
   SCH_QuitProgram();
 }
 
+/* ================================================== */
+
+static void
+handle_ntp_source_name(CMD_Request *rx_message, CMD_Reply *tx_message)
+{
+  IPAddr addr;
+  char *name;
+
+  UTI_IPNetworkToHost(&rx_message->data.ntp_data.ip_addr, &addr);
+  name = NSR_GetName(&addr);
+
+  if (!name) {
+    tx_message->status = htons(STT_NOSUCHSOURCE);
+    return;
+  }
+
+  tx_message->reply = htons(RPY_NTP_SOURCE_NAME);
+
+  /* Avoid compiler warning */
+  if (strlen(name) >= sizeof (tx_message->data.ntp_source_name.name))
+    memcpy(tx_message->data.ntp_source_name.name, name,
+           sizeof (tx_message->data.ntp_source_name.name));
+  else
+    strncpy((char *)tx_message->data.ntp_source_name.name, name,
+            sizeof (tx_message->data.ntp_source_name.name));
+}
+
 /* ================================================== */
 /* Read a packet and process it */
 
@@ -1561,6 +1589,10 @@ read_from_cmd_socket(int sock_fd, int event, void *anything)
           handle_onoffline(&rx_message, &tx_message);
           break;
 
+        case REQ_NTP_SOURCE_NAME:
+          handle_ntp_source_name(&rx_message, &tx_message);
+          break;
+
         default:
           DEBUG_LOG("Unhandled command %d", rx_command);
           tx_message.status = htons(STT_FAILED);

ntp_sources.c

@@ -782,6 +782,29 @@ NSR_GetLocalRefid(IPAddr *address)
 
 /* ================================================== */
 
+char *
+NSR_GetName(IPAddr *address)
+{
+  NTP_Remote_Address remote_addr;
+  int slot, found;
+  SourceRecord *record;
+
+  remote_addr.ip_addr = *address;
+  remote_addr.port = 0;
+
+  find_slot(&remote_addr, &slot, &found);
+  if (!found)
+    return NULL;
+
+  record = get_record(slot);
+  if (record->name)
+    return record->name;
+
+  return UTI_IPToString(&record->remote_addr->ip_addr); 
+}
+
+/* ================================================== */
+
 /* This routine is called by ntp_io when a new packet arrives off the network,
    possibly with an authentication tail */
 void

ntp_sources.h

@@ -90,6 +90,10 @@ extern void NSR_RefreshAddresses(void);
 /* Procedure to get local reference ID corresponding to a source */
 extern uint32_t NSR_GetLocalRefid(IPAddr *address);
 
+/* Procedure to get the name of a source.  If the source doesn't have a name,
+   it returns a temporary string containing formatted address. */
+extern char *NSR_GetName(IPAddr *address);
+
 /* This routine is called by ntp_io when a new packet arrives off the network */
 extern void NSR_ProcessRx(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
                           NTP_Local_Timestamp *rx_ts, NTP_Packet *message, int length);

pktlength.c

@@ -121,6 +121,8 @@ static const struct request_length request_lengths[] = {
   REQ_LENGTH_ENTRY(null, null),                 /* SHUTDOWN */
   REQ_LENGTH_ENTRY(null, null),                 /* ONOFFLINE */
   REQ_LENGTH_ENTRY(ntp_source, null),           /* ADD_SOURCE */
+  REQ_LENGTH_ENTRY(ntp_source_name,
+                   ntp_source_name),            /* NTP_SOURCE_NAME */
 };
 
 static const uint16_t reply_lengths[] = {
@@ -143,6 +145,7 @@ static const uint16_t reply_lengths[] = {
   RPY_LENGTH_ENTRY(ntp_data),                   /* NTP_DATA */
   RPY_LENGTH_ENTRY(manual_timestamp),           /* MANUAL_TIMESTAMP2 */
   RPY_LENGTH_ENTRY(manual_list),                /* MANUAL_LIST2 */
+  RPY_LENGTH_ENTRY(ntp_source_name),            /* NTP_SOURCE_NAME */
 };
 
 /* ================================================== */