Fix bug #3, sid allocation overflow. May lead to double SIDs being given out.

src/adc/sid.c

@@ -59,3 +59,72 @@ sid_t string_to_sid(const char* sid)
 	return nsid;
 }
 
+/*
+ * Session IDs are heavily reused, since they are a fairly scarce
+ * resource. Only one (2^10)-1 exist, since it is a four byte base32-encoded
+ * value and 'AAAA' (0) is reserved for the hub.
+ *
+ * Initialize with sid_initialize(), which sets min and max to one, and count to 0.
+ *
+ * When allocating a session ID:
+ * - If 'count' is less than the pool size (max-min), then allocate within the pool
+ * - Increase the pool size (see below)
+ * - If unable to do that, hub is really full - don't let anyone in!
+ *
+ * When freeing a session ID:
+ * - If the session ID being freed is 'max', then decrease the pool size by one.
+ *
+ */
+
+struct sid_pool
+{
+	sid_t min;
+	sid_t max;
+	sid_t count;
+	struct hub_user** map;
+};
+
+
+struct sid_pool* sid_pool_create(sid_t max)
+{
+	struct sid_pool* pool = hub_malloc(sizeof(struct sid_pool));
+	pool->min = 1;
+	pool->max = max + 1;
+	pool->count = 0;
+	pool->map = hub_malloc_zero(sizeof(struct hub_user*) * pool->max);
+	pool->map[0] = (struct hub_user*) pool; /* hack to reserve the first sid. */
+
+	LOG_DUMP("SID_POOL:  max=%d", (int) pool->max);
+	return pool;
+}
+
+void sid_pool_destroy(struct sid_pool* pool)
+{
+	LOG_DUMP("SID_POOL:  destroying, current allocs=%d", (int) pool->count);
+	hub_free(pool->map);
+	hub_free(pool);
+}
+
+sid_t sid_alloc(struct sid_pool* pool, struct hub_user* user)
+{
+	sid_t n = (++pool->count);
+	for (; (pool->map[n % pool->max]); n++) ;
+
+	LOG_DUMP("SID_ALLOC: %d, user=%p", (int) n, user);
+	pool->map[n] = user;
+	return n;
+}
+
+void sid_free(struct sid_pool* pool, sid_t sid)
+{
+	LOG_DUMP("SID_FREE:  %d", (int) sid);
+	pool->map[sid] = 0;
+	pool->count--;
+}
+
+struct hub_user* sid_lookup(struct sid_pool* pool, sid_t sid)
+{
+	if (!sid || (sid > pool->max))
+		return 0;
+	return pool->map[sid];
+}

src/adc/sid.h

@@ -22,44 +22,19 @@
 
 #define SID_MAX 1048576
 
+struct sid_pool;
+struct hub_user;
+
 extern const char* BASE32_ALPHABET;
 extern char* sid_to_string(sid_t sid_);
 extern sid_t string_to_sid(const char* sid);
 
-struct sid_map
-{
-	struct hub_user* ptr;
-	struct sid_map* next;
-};
+extern struct sid_pool* sid_pool_create(sid_t max);
+extern void sid_pool_destroy(struct sid_pool*);
 
-/**
- * Session IDs are heavily reused, since they are a fairly scarce
- * resource. Only one (2^10)-1 exist, since it is a four byte base32-encoded
- * value and 'AAAA' (0) is reserved for the hub.
- *
- * Initialize with sid_initialize(), which sets min and max to one, and count to 0.
- *
- * When allocating a session ID:
- * - If 'count' is less than the pool size (max-min), then allocate within the pool
- * - Increase the pool size (see below)
- * - If unable to do that, hub is really full - don't let anyone in!
- *
- * When freeing a session ID:
- * - If the session ID being freed is 'max', then decrease the pool size by one.
- *
- */
-struct sid_pool
-{
-	sid_t min;
-	sid_t max;
-	sid_t count;
-	struct sid_map* map;
-};
-
-
-extern void sid_initialize(struct sid_pool*);
 extern sid_t sid_alloc(struct sid_pool*, struct hub_user*);
 extern void sid_free(struct sid_pool*, sid_t);
+extern struct hub_user* sid_lookup(struct sid_pool*, sid_t);
 
 
 

src/core/hub.c

@@ -238,12 +238,13 @@ void hub_send_support(struct hub_info* hub, struct hub_user* u)
 
 void hub_send_sid(struct hub_info* hub, struct hub_user* u)
 {
+	sid_t sid;
 	struct adc_message* command;
 	if (user_is_connecting(u))
 	{
 		command = adc_msg_construct(ADC_CMD_ISID, 10);
-		u->id.sid = uman_get_free_sid(hub);
-		adc_msg_add_argument(command, (const char*) sid_to_string(u->id.sid));
+		sid = uman_get_free_sid(hub, u);
+		adc_msg_add_argument(command, (const char*) sid_to_string(sid));
 		route_to_user(hub, u, command);
 		adc_msg_free(command);
 	}
@@ -958,6 +959,11 @@ void hub_schedule_destroy_user(struct hub_info* hub, struct hub_user* user)
 	post.id = UHUB_EVENT_USER_DESTROY;
 	post.ptr = user;
 	event_queue_post(hub->queue, &post);
+
+	if (user->id.sid)
+	{
+		sid_free(hub->users->sids, user->id.sid);
+	}
 }
 
 void hub_disconnect_user(struct hub_info* hub, struct hub_user* user, int reason)

src/core/user.c

@@ -58,7 +58,6 @@ struct hub_user* user_create(struct hub_info* hub, int sd)
 	evtimer_set(&user->net.timeout, net_event, user);
 	event_base_set(hub->evbase, &user->net.timeout);
 
-
 	user_set_timeout(user, TIMEOUT_CONNECTED);
 
 	user_set_state(user, state_protocol);
@@ -215,12 +214,6 @@ void user_support_remove(struct hub_user* user, int fourcc)
 	user->flags &= ~feature_mask;
 }
 
-void user_disconnect(struct hub_user* user, int reason)
-{
-
-
-}
-
 int user_have_feature_cast_support(struct hub_user* user, char feature[4])
 {
 	char* tmp = list_get_first(user->feature_cast);

src/core/user.h

@@ -147,22 +147,6 @@ extern struct hub_user* user_create(struct hub_info* hub, int sd);
  */
 extern void user_destroy(struct hub_user* user);
 
-/**
- * Disconnect a user.
- * This will mark the user connection ready for being terminated.
- * A reason can be given using the enum user_quit_reason.
- *
- * Things to be done when calling this:
- * - Mark the user with state_cleanup
- *
- * If the user is logged in to the hub:
- * - post message: UHUB_EVENT_USER_QUIT
- *
- * @param user User to disconnect
- * @param reason See enum user_quit_reason
- */
-extern void user_disconnect(struct hub_user* user, int reason);
-
 /**
  * This associates a INF message to the user.
  * If the user already has a INF message associated, then this is

src/core/usermanager.c

@@ -97,7 +97,7 @@ int uman_init(struct hub_info* hub)
 		return -1;
 
 	users->list = list_create();
-	users->free_sid = 1;
+	users->sids = sid_pool_create(MAX(1024, (hub->config->max_users + 24)));
 	
 	if (!users->list)
 	{
@@ -134,6 +134,7 @@ int uman_shutdown(struct hub_info* hub)
 		list_clear(hub->users->list, &clear_user_list_callback);
 		list_destroy(hub->users->list);
 	}
+	sid_pool_destroy(hub->users->sids);
 	hub_free(hub->users);
 	hub->users = 0;
 
@@ -187,14 +188,7 @@ int uman_remove(struct hub_info* hub, struct hub_user* user)
 
 struct hub_user* uman_get_user_by_sid(struct hub_info* hub, sid_t sid)
 {
-	struct hub_user* user = (struct hub_user*) list_get_first(hub->users->list); /* iterate users */
-	while (user)
-	{
-		if (user->id.sid == sid)
-			return user;
-		user = (struct hub_user*) list_get_next(hub->users->list);
-	}
-	return NULL;
+	return sid_lookup(hub->users->sids, sid);
 }
 
 
@@ -275,28 +269,15 @@ void uman_send_quit_message(struct hub_info* hub, struct hub_user* leaving)
 	{
 		adc_msg_add_argument(command, ADC_QUI_FLAG_DISCONNECT);
 	}
-	
 	route_to_all(hub, command);
 	adc_msg_free(command);
 }
 
 
-sid_t uman_get_free_sid(struct hub_info* hub)
+sid_t uman_get_free_sid(struct hub_info* hub, struct hub_user* user)
 {
-#if 0
-	struct hub_user* user;
-	user = (struct hub_user*) list_get_first(hub->users->list); /* iterate normal users */
-	while (user)
-	{
-		if (user->sid == hub->users->free_sid)
-		{
-			hub->users->free_sid++;
-			if (hub->users->free_sid >= SID_MAX) hub->users->free_sid = 1;
-			break;
-		}
-		user = (struct hub_user*) list_get_next(hub->users->list);
-	}
-#endif
-	return hub->users->free_sid++;
+	sid_t sid = sid_alloc(hub->users->sids, user);
+	user->id.sid = sid;
+	return sid;
 }
 

src/core/usermanager.h

@@ -24,7 +24,7 @@ struct hub_user_manager
 {
 	size_t count;                   /**<< "Number of all fully connected and logged in users" */
 	size_t count_peak;              /**<< "Peak number of users" */
-	sid_t free_sid;                 /**<< "The next available SID." */
+	struct sid_pool* sids;
 	uint64_t shared_size;           /**<< "The total number of shared bytes among fully connected users." */
 	uint64_t shared_files;          /**<< "The total number of shared files among fully connected users." */
 	struct linked_list* list;       /**<< "Contains all users" */
@@ -70,7 +70,7 @@ extern int uman_remove(struct hub_info* hub, struct hub_user* user);
 /**
  * Returns and allocates an unused session ID (SID).
  */
-extern sid_t uman_get_free_sid(struct hub_info* hub);
+extern sid_t uman_get_free_sid(struct hub_info* hub, struct hub_user* user);
 
 /**
  * Lookup a user based on the session ID (SID).