Fix issues with Global Allocation Count for drain mode (#1699)

Fix issues with Global Allocation Count for drain mode

- move increment/decrement logic out of userdb.c and tie to Prometheus
logic for allocation tracking instead
- log global allocation count decrements at INFO level, when drain mode
is on

src/apps/relay/mainrelay.c

@@ -44,6 +44,13 @@
 #define MAX_TRIES 3
 #endif
 
+#ifdef _MSC_VER
+volatile
+#else
+_Atomic
+#endif
+    size_t global_allocation_count = 0; // used for drain mode, to know when all allocations have gone away
+
 ////// TEMPORARY data //////////
 
 static int use_lt_credentials = 0;
@@ -3857,4 +3864,30 @@ static void drain_handler(evutil_socket_t sock, short events, void *args) {
   UNUSED_ARG(args);
 }
 
+void increment_global_allocation_count(void) {
+#ifdef _MSC_VER
+  size_t cur_count = InterlockedIncrement(&global_allocation_count);
+#else
+  size_t cur_count = ++global_allocation_count;
+#endif
+  if (turn_params.verbose > TURN_VERBOSE_NONE) {
+    TURN_LOG_FUNC(TURN_LOG_LEVEL_DEBUG, "Global turn allocation count incremented, now %zu\n", cur_count);
+  }
+}
+
+void decrement_global_allocation_count(void) {
+  int log_level = TURN_LOG_LEVEL_DEBUG;
+  if (turn_params.drain_turn_server) {
+    log_level = TURN_LOG_LEVEL_INFO;
+  }
+#ifdef _MSC_VER
+  size_t cur_count = InterlockedDecrement(&global_allocation_count);
+#else
+  size_t cur_count = --global_allocation_count;
+#endif
+  if (turn_params.drain_turn_server || turn_params.verbose > TURN_VERBOSE_NONE) {
+    TURN_LOG_FUNC(log_level, "Global turn allocation count decremented, now %zu\n", cur_count);
+  }
+}
+
 ///////////////////////////////

src/apps/relay/mainrelay.h

@@ -101,6 +101,14 @@
 extern "C" {
 #endif
 
+#ifdef _MSC_VER
+extern volatile
+#else
+#include <stdatomic.h>
+extern _Atomic
+#endif
+    size_t global_allocation_count; // used for drain mode, to know when all allocations have gone away
+
 ////////////// DEFINES ////////////////////////////
 
 #define DEFAULT_CONFIG_FILE "turnserver.conf"
@@ -409,6 +417,9 @@ int init_ctr(struct ctr_state *state, const unsigned char iv[8]);
 
 ///////////////////////////////
 
+void increment_global_allocation_count(void);
+void decrement_global_allocation_count(void);
+
 #ifdef __cplusplus
 }
 #endif

src/apps/relay/ns_ioalib_engine_impl.c

@@ -42,6 +42,7 @@
 
 #include "ns_ioalib_impl.h"
 
+#include "mainrelay.h"
 #include "prom_server.h"
 
 #if TLS_SUPPORTED
@@ -3668,6 +3669,7 @@ void turn_report_allocation_set(void *a, turn_time_t lifetime, int refresh) {
         {
           if (!refresh) {
             prom_inc_allocation(get_ioa_socket_type(ss->client_socket));
+            increment_global_allocation_count();
           }
         }
       }
@@ -3745,6 +3747,7 @@ void turn_report_allocation_delete(void *a, SOCKET_TYPE socket_type) {
                                       true);
           }
           prom_dec_allocation(socket_type);
+          decrement_global_allocation_count();
         }
       }
     }

src/apps/relay/userdb.c

@@ -72,13 +72,6 @@ static TURN_MUTEX_DECLARE(o_to_realm_mutex);
 static ur_string_map *o_to_realm = NULL;
 static secrets_list_t realms_list;
 
-#ifndef _MSC_VER
-_Atomic
-#else
-volatile
-#endif
-    size_t global_allocation_count = 0; // used for drain mode, to know when all allocations have gone away
-
 static char userdb_type_unknown[] = "Unknown";
 static char userdb_type_sqlite[] = "SQLite";
 static char userdb_type_postgresql[] = "PostgreSQL";
@@ -695,15 +688,6 @@ int check_new_allocation_quota(uint8_t *user, int oauth, uint8_t *realm) {
     ur_string_map_unlock(rp->status.alloc_counters);
   }
 
-#ifndef _MSC_VER
-  size_t cur_count = ++global_allocation_count;
-#else
-  size_t cur_count = (size_t)InterlockedIncrement((volatile LONG *)&global_allocation_count);
-#endif
-  if (turn_params.verbose > TURN_VERBOSE_NONE) {
-    TURN_LOG_FUNC(TURN_LOG_LEVEL_DEBUG, "Global turn allocation count incremented, now %ld\n", cur_count);
-  }
-
   return ret;
 }
 
@@ -730,19 +714,6 @@ void release_allocation_quota(uint8_t *user, int oauth, uint8_t *realm) {
     ur_string_map_unlock(rp->status.alloc_counters);
     free(username);
   }
-
-  int log_level = TURN_LOG_LEVEL_DEBUG;
-  if (turn_params.drain_turn_server) {
-    log_level = TURN_LOG_LEVEL_INFO;
-  }
-#ifndef _MSC_VER
-  size_t cur_count = --global_allocation_count;
-#else
-  size_t cur_count = (size_t)InterlockedDecrement((volatile LONG *)&global_allocation_count);
-#endif
-  if (turn_params.verbose > TURN_VERBOSE_NONE) {
-    TURN_LOG_FUNC(log_level, "Global turn allocation count decremented, now %ld\n", cur_count);
-  }
 }
 
 //////////////////////////////////

src/apps/relay/userdb.h

@@ -50,14 +50,6 @@
 extern "C" {
 #endif
 
-#ifndef _MSC_VER
-#include <stdatomic.h>
-extern _Atomic
-#else
-extern volatile
-#endif
-    size_t global_allocation_count;
-
 //////////// REALM //////////////
 
 struct _realm_status_t;