vector: Update API to be more flexible.

Made the vector macro API be more like linked lists.
1) Added a name parameter to ast_vector() to name the vector struct.
2) Made the API take a pointer to the vector struct instead of the struct
itself.
3) Added an element cleanup macro/function parameter when removing an
element from the vector for ast_vector_remove_cmp_unordered() and
ast_vector_remove_elem_unordered().
4) Added ast_vector_get_addr() in case the vector element is not a simple
pointer.

* Converted an inline vector usage in stasis_message_router to use the
vector API.  It needed the API improvements so it could be converted.

* Fixed topic reference leak in router_dtor() when the
stasis_message_router is destroyed.

* Fixed deadlock potential in stasis_forward_all() and
stasis_forward_cancel().  Locking two topics at the same time requires
deadlock avoidance.

* Made internal_stasis_subscribe() tolerant of a NULL topic.

* Made stasis_message_router_add(),
stasis_message_router_add_cache_update(), stasis_message_router_remove(),
and stasis_message_router_remove_cache_update() tolerant of a NULL
message_type.

* Promoted a LOG_DEBUG message to LOG_ERROR as intended in
dispatch_message().

Review: https://reviewboard.asterisk.org/r/2903/
........

Merged revisions 402429 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@402430 65c4cc65-6c06-0410-ace0-fbb531ad65f3

4 files changed, 300 insertions, 173 deletions

diff --git a/include/asterisk/lock.h b/include/asterisk/lock.h
index d76a8d185..7741654a0 100644
--- a/include/asterisk/lock.h
+++ b/include/asterisk/lock.h
@@ -339,6 +339,28 @@ int ast_find_lock_info(void *lock_addr, char *filename, size_t filename_size, in
  * used during deadlock avoidance, to preserve the original location where
  * a lock was originally acquired.
  */
+#define AO2_DEADLOCK_AVOIDANCE(obj) \
+	do { \
+		char __filename[80], __func[80], __mutex_name[80]; \
+		int __lineno; \
+		int __res = ast_find_lock_info(ao2_object_get_lockaddr(obj), __filename, sizeof(__filename), &__lineno, __func, sizeof(__func), __mutex_name, sizeof(__mutex_name)); \
+		int __res2 = ao2_unlock(obj); \
+		usleep(1); \
+		if (__res < 0) { /* Could happen if the ao2 object does not have a mutex. */ \
+			if (__res2) { \
+				ast_log(LOG_WARNING, "Could not unlock ao2 object '%s': %s and no lock info found!  I will NOT try to relock.\n", #obj, strerror(__res2)); \
+			} else { \
+				ao2_lock(obj); \
+			} \
+		} else { \
+			if (__res2) { \
+				ast_log(LOG_WARNING, "Could not unlock ao2 object '%s': %s.  {{{Originally locked at %s line %d: (%s) '%s'}}}  I will NOT try to relock.\n", #obj, strerror(__res2), __filename, __lineno, __func, __mutex_name); \
+			} else { \
+				__ao2_lock(obj, AO2_LOCK_REQ_MUTEX, __filename, __func, __lineno, __mutex_name); \
+			} \
+		} \
+	} while (0)
+
 #define CHANNEL_DEADLOCK_AVOIDANCE(chan) \
 	do { \
 		char __filename[80], __func[80], __mutex_name[80]; \
@@ -493,12 +515,17 @@ static inline void delete_reentrancy_cs(struct ast_lock_track **plt)
 
 #else /* !DEBUG_THREADS */
 
-#define	CHANNEL_DEADLOCK_AVOIDANCE(chan) \
+#define AO2_DEADLOCK_AVOIDANCE(obj) \
+	ao2_unlock(obj); \
+	usleep(1); \
+	ao2_lock(obj);
+
+#define CHANNEL_DEADLOCK_AVOIDANCE(chan) \
 	ast_channel_unlock(chan); \
 	usleep(1); \
 	ast_channel_lock(chan);
 
-#define	DEADLOCK_AVOIDANCE(lock) \
+#define DEADLOCK_AVOIDANCE(lock) \
 	do { \
 		int __res; \
 		if (!(__res = ast_mutex_unlock(lock))) { \
diff --git a/include/asterisk/vector.h b/include/asterisk/vector.h
index f5d3e9a14..4efc5ce4f 100644
--- a/include/asterisk/vector.h
+++ b/include/asterisk/vector.h
@@ -33,9 +33,14 @@
  * \since 12
  */
 
-/*! \brief Define a vector structure */
-#define ast_vector(type)			\
-	struct {				\
+/*!
+ * \brief Define a vector structure
+ *
+ * \param name Optional vector struct name.
+ * \param type Vector element type.
+ */
+#define ast_vector(name, type)			\
+	struct name {				\
 		type *elems;			\
 		size_t max;			\
 		size_t current;			\
@@ -55,15 +60,15 @@
  */
 #define ast_vector_init(vec, size) ({					\
 	size_t __size = (size);						\
-	size_t alloc_size = __size * sizeof(*(vec).elems);		\
-	(vec).elems = alloc_size ? ast_malloc(alloc_size) : NULL;	\
-	(vec).current = 0;						\
-	if ((vec).elems) {						\
-		(vec).max = __size;					\
+	size_t alloc_size = __size * sizeof(*((vec)->elems));		\
+	(vec)->elems = alloc_size ? ast_malloc(alloc_size) : NULL;	\
+	(vec)->current = 0;						\
+	if ((vec)->elems) {						\
+		(vec)->max = __size;					\
 	} else {							\
-		(vec).max = 0;						\
+		(vec)->max = 0;						\
 	}								\
-	alloc_size == 0 || (vec).elems != NULL ? 0 : -1;		\
+	(alloc_size == 0 || (vec)->elems != NULL) ? 0 : -1;		\
 })
 
 /*!
@@ -75,10 +80,10 @@
  * \param vec Vector to deallocate.
  */
 #define ast_vector_free(vec) do {		\
-	ast_free((vec).elems);			\
-	(vec).elems = NULL;			\
-	(vec).max = 0;				\
-	(vec).current = 0;			\
+	ast_free((vec)->elems);			\
+	(vec)->elems = NULL;			\
+	(vec)->max = 0;				\
+	(vec)->current = 0;			\
 } while (0)
 
 /*!
@@ -90,25 +95,24 @@
  * \return 0 on success.
  * \return Non-zero on failure.
  */
-#define ast_vector_append(vec, elem) ({					\
-	int res = 0;							\
-									\
-	if ((vec).current + 1 > (vec).max) {				\
-		size_t new_max = (vec).max ? 2 * (vec).max : 1;		\
-		typeof((vec).elems) new_elems = ast_realloc(		\
-			(vec).elems, new_max * sizeof(*new_elems));	\
-		if (new_elems) {					\
-			(vec).elems = new_elems;				\
-			(vec).max = new_max;				\
-		} else {						\
-			res = -1;					\
-		}							\
-	}								\
-									\
-	if (res == 0) {							\
-		(vec).elems[(vec).current++] = (elem);			\
-	}								\
-	res;								\
+#define ast_vector_append(vec, elem) ({						\
+	int res = 0;								\
+	do {									\
+		if ((vec)->current + 1 > (vec)->max) {				\
+			size_t new_max = (vec)->max ? 2 * (vec)->max : 1;	\
+			typeof((vec)->elems) new_elems = ast_realloc(		\
+				(vec)->elems, new_max * sizeof(*new_elems));	\
+			if (new_elems) {					\
+				(vec)->elems = new_elems;			\
+				(vec)->max = new_max;				\
+			} else {						\
+				res = -1;					\
+				break;						\
+			}							\
+		}								\
+		(vec)->elems[(vec)->current++] = (elem);			\
+	} while (0);								\
+	res;									\
 })
 
 /*!
@@ -122,11 +126,11 @@
  * \return The element that was removed.
  */
 #define ast_vector_remove_unordered(vec, idx) ({		\
-	typeof((vec).elems[0]) res;				\
+	typeof((vec)->elems[0]) res;				\
 	size_t __idx = (idx);					\
-	ast_assert(__idx < (vec).current);			\
-	res = (vec).elems[__idx];				\
-	(vec).elems[__idx] = (vec).elems[--(vec).current];	\
+	ast_assert(__idx < (vec)->current);			\
+	res = (vec)->elems[__idx];				\
+	(vec)->elems[__idx] = (vec)->elems[--(vec)->current];	\
 	res;							\
 })
 
@@ -137,15 +141,18 @@
  * \param vec Vector to remove from.
  * \param value Value to pass into comparator.
  * \param cmp Comparator function/macros (called as \c cmp(elem, value))
+ * \param cleanup How to cleanup a removed element macro/function.
+ *
  * \return 0 if element was removed.
  * \return Non-zero if element was not in the vector.
  */
-#define ast_vector_remove_cmp_unordered(vec, value, cmp) ({		\
+#define ast_vector_remove_cmp_unordered(vec, value, cmp, cleanup) ({	\
 	int res = -1;							\
 	size_t idx;							\
 	typeof(value) __value = (value);				\
-	for (idx = 0; idx < (vec).current; ++idx) {			\
-		if (cmp((vec).elems[idx], __value)) {			\
+	for (idx = 0; idx < (vec)->current; ++idx) {			\
+		if (cmp((vec)->elems[idx], __value)) {			\
+			cleanup((vec)->elems[idx]);			\
 			ast_vector_remove_unordered((vec), idx);	\
 			res = 0;					\
 			break;						\
@@ -154,20 +161,39 @@
 	res;								\
 })
 
-/*! \brief Default comparator for ast_vector_remove_elem_unordered() */
-#define AST_VECTOR_DEFAULT_CMP(a, b) ((a) == (b))
+/*!
+ * \brief Default comparator for ast_vector_remove_elem_unordered()
+ *
+ * \param elem Element to compare against
+ * \param value Value to compare with the vector element.
+ *
+ * \return 0 if element does not match.
+ * \return Non-zero if element matches.
+ */
+#define AST_VECTOR_ELEM_DEFAULT_CMP(elem, value) ((elem) == (value))
+
+/*!
+ * \brief Vector element cleanup that does nothing.
+ *
+ * \param elem Element to cleanup
+ *
+ * \return Nothing
+ */
+#define AST_VECTOR_ELEM_CLEANUP_NOOP(elem)
 
 /*!
  * \brief Remove an element from a vector.
  *
  * \param vec Vector to remove from.
  * \param elem Element to remove
+ * \param cleanup How to cleanup a removed element macro/function.
+ *
  * \return 0 if element was removed.
  * \return Non-zero if element was not in the vector.
  */
-#define ast_vector_remove_elem_unordered(vec, elem) ({	\
-	ast_vector_remove_cmp_unordered((vec), (elem),	\
-		AST_VECTOR_DEFAULT_CMP);		\
+#define ast_vector_remove_elem_unordered(vec, elem, cleanup) ({	\
+	ast_vector_remove_cmp_unordered((vec), (elem),		\
+		AST_VECTOR_ELEM_DEFAULT_CMP, cleanup);		\
 })
 
 /*!
@@ -176,7 +202,19 @@
  * \param vec Vector to query.
  * \return Number of elements in the vector.
  */
-#define ast_vector_size(vec) (vec).current
+#define ast_vector_size(vec) (vec)->current
+
+/*!
+ * \brief Get an address of element in a vector.
+ *
+ * \param vec Vector to query.
+ * \param idx Index of the element to get address of.
+ */
+#define ast_vector_get_addr(vec, idx) ({	\
+	size_t __idx = (idx);			\
+	ast_assert(__idx < (vec)->current);	\
+	&(vec)->elems[__idx];			\
+})
 
 /*!
  * \brief Get an element from a vector.
@@ -186,8 +224,8 @@
  */
 #define ast_vector_get(vec, idx) ({		\
 	size_t __idx = (idx);			\
-	ast_assert(__idx < (vec).current);	\
-	(vec).elems[__idx];			\
+	ast_assert(__idx < (vec)->current);	\
+	(vec)->elems[__idx];			\
 })
 
 #endif /* _ASTERISK_VECTOR_H */
diff --git a/main/stasis.c b/main/stasis.c
index eabdfdc1c..db95986ed 100644
--- a/main/stasis.c
+++ b/main/stasis.c
@@ -140,10 +140,10 @@ STASIS_MESSAGE_TYPE_DEFN(stasis_subscription_change_type);
 struct stasis_topic {
 	char *name;
 	/*! Variable length array of the subscribers */
-	ast_vector(struct stasis_subscription *) subscribers;
+	ast_vector(, struct stasis_subscription *) subscribers;
 
 	/*! Topics forwarding into this topic */
-	ast_vector(struct stasis_topic *) upstream_topics;
+	ast_vector(, struct stasis_topic *) upstream_topics;
 };
 
 /* Forward declarations for the tightly-coupled subscription object */
@@ -152,18 +152,28 @@ static int topic_add_subscription(struct stasis_topic *topic,
 
 static int topic_remove_subscription(struct stasis_topic *topic, struct stasis_subscription *sub);
 
+/*! \brief Lock two topics. */
+#define topic_lock_both(topic1, topic2) \
+	do { \
+		ao2_lock(topic1); \
+		while (ao2_trylock(topic2)) { \
+			AO2_DEADLOCK_AVOIDANCE(topic1); \
+		} \
+	} while (0)
+
 static void topic_dtor(void *obj)
 {
 	struct stasis_topic *topic = obj;
 
 	/* Subscribers hold a reference to topics, so they should all be
 	 * unsubscribed before we get here. */
-	ast_assert(ast_vector_size(topic->subscribers) == 0);
+	ast_assert(ast_vector_size(&topic->subscribers) == 0);
+
 	ast_free(topic->name);
 	topic->name = NULL;
 
-	ast_vector_free(topic->subscribers);
-	ast_vector_free(topic->upstream_topics);
+	ast_vector_free(&topic->subscribers);
+	ast_vector_free(&topic->upstream_topics);
 }
 
 struct stasis_topic *stasis_topic_create(const char *name)
@@ -182,8 +192,8 @@ struct stasis_topic *stasis_topic_create(const char *name)
 		return NULL;
 	}
 
-	res |= ast_vector_init(topic->subscribers, INITIAL_SUBSCRIBERS_MAX);
-	res |= ast_vector_init(topic->upstream_topics, 0);
+	res |= ast_vector_init(&topic->subscribers, INITIAL_SUBSCRIBERS_MAX);
+	res |= ast_vector_init(&topic->upstream_topics, 0);
 
 	if (res != 0) {
 		return NULL;
@@ -280,6 +290,10 @@ struct stasis_subscription *internal_stasis_subscribe(
 {
 	RAII_VAR(struct stasis_subscription *, sub, NULL, ao2_cleanup);
 
+	if (!topic) {
+		return NULL;
+	}
+
 	sub = ao2_alloc(sizeof(*sub), subscription_dtor);
 	if (!sub) {
 		return NULL;
@@ -414,8 +428,8 @@ int stasis_subscription_is_subscribed(const struct stasis_subscription *sub)
 		struct stasis_topic *topic = sub->topic;
 		SCOPED_AO2LOCK(lock_topic, topic);
 
-		for (i = 0; i < ast_vector_size(topic->subscribers); ++i) {
-			if (ast_vector_get(topic->subscribers, i) == sub) {
+		for (i = 0; i < ast_vector_size(&topic->subscribers); ++i) {
+			if (ast_vector_get(&topic->subscribers, i) == sub) {
 				return 1;
 			}
 		}
@@ -466,11 +480,11 @@ static int topic_add_subscription(struct stasis_topic *topic, struct stasis_subs
 	 *
 	 * If we bumped the refcount here, the owner would have to unsubscribe
 	 * and cleanup, which is a bit awkward. */
-	ast_vector_append(topic->subscribers, sub);
+	ast_vector_append(&topic->subscribers, sub);
 
-	for (idx = 0; idx < ast_vector_size(topic->upstream_topics); ++idx) {
+	for (idx = 0; idx < ast_vector_size(&topic->upstream_topics); ++idx) {
 		topic_add_subscription(
-			ast_vector_get(topic->upstream_topics, idx), sub);
+			ast_vector_get(&topic->upstream_topics, idx), sub);
 	}
 
 	return 0;
@@ -481,12 +495,13 @@ static int topic_remove_subscription(struct stasis_topic *topic, struct stasis_s
 	size_t idx;
 	SCOPED_AO2LOCK(lock_topic, topic);
 
-	for (idx = 0; idx < ast_vector_size(topic->upstream_topics); ++idx) {
+	for (idx = 0; idx < ast_vector_size(&topic->upstream_topics); ++idx) {
 		topic_remove_subscription(
-			ast_vector_get(topic->upstream_topics, idx), sub);
+			ast_vector_get(&topic->upstream_topics, idx), sub);
 	}
 
-	return ast_vector_remove_elem_unordered(topic->subscribers, sub);
+	return ast_vector_remove_elem_unordered(&topic->subscribers, sub,
+		AST_VECTOR_ELEM_CLEANUP_NOOP);
 }
 
 /*!
@@ -512,7 +527,7 @@ static void dispatch_message(struct stasis_subscription *sub,
 		ao2_bump(message);
 		if (ast_taskprocessor_push_local(sub->mailbox, dispatch_exec, message) != 0) {
 			/* Push failed; ugh. */
-			ast_log(LOG_DEBUG, "Dropping dispatch\n");
+			ast_log(LOG_ERROR, "Dropping dispatch\n");
 			ao2_cleanup(message);
 		}
 	} else {
@@ -521,26 +536,28 @@ static void dispatch_message(struct stasis_subscription *sub,
 	}
 }
 
-void stasis_publish(struct stasis_topic *_topic, struct stasis_message *message)
+void stasis_publish(struct stasis_topic *topic, struct stasis_message *message)
 {
 	size_t i;
-	/* The topic may be unref'ed by the subscription invocation.
-	 * Make sure we hold onto a reference while dispatching. */
-	RAII_VAR(struct stasis_topic *, topic, ao2_bump(_topic),
-		ao2_cleanup);
-	SCOPED_AO2LOCK(lock, topic);
 
 	ast_assert(topic != NULL);
 	ast_assert(message != NULL);
 
-	for (i = 0; i < ast_vector_size(topic->subscribers); ++i) {
-		struct stasis_subscription *sub =
-			ast_vector_get(topic->subscribers, i);
+	/*
+	 * The topic may be unref'ed by the subscription invocation.
+	 * Make sure we hold onto a reference while dispatching.
+	 */
+	ao2_ref(topic, +1);
+	ao2_lock(topic);
+	for (i = 0; i < ast_vector_size(&topic->subscribers); ++i) {
+		struct stasis_subscription *sub = ast_vector_get(&topic->subscribers, i);
 
 		ast_assert(sub != NULL);
 
 		dispatch_message(sub, message);
 	}
+	ao2_unlock(topic);
+	ao2_ref(topic, -1);
 }
 
 /*!
@@ -570,23 +587,26 @@ static void forward_dtor(void *obj)
 
 struct stasis_forward *stasis_forward_cancel(struct stasis_forward *forward)
 {
-	if (forward) {
-		int idx;
+	int idx;
+	struct stasis_topic *from;
+	struct stasis_topic *to;
 
-		struct stasis_topic *from = forward->from_topic;
-		struct stasis_topic *to = forward->to_topic;
+	if (!forward) {
+		return NULL;
+	}
 
-		SCOPED_AO2LOCK(to_lock, to);
+	from = forward->from_topic;
+	to = forward->to_topic;
 
-		ast_vector_remove_elem_unordered(to->upstream_topics, from);
+	topic_lock_both(to, from);
+	ast_vector_remove_elem_unordered(&to->upstream_topics, from,
+		AST_VECTOR_ELEM_CLEANUP_NOOP);
 
-		ao2_lock(from);
-		for (idx = 0; idx < ast_vector_size(to->subscribers); ++idx) {
-			topic_remove_subscription(
-				from, ast_vector_get(to->subscribers, idx));
-		}
-		ao2_unlock(from);
+	for (idx = 0; idx < ast_vector_size(&to->subscribers); ++idx) {
+		topic_remove_subscription(from, ast_vector_get(&to->subscribers, idx));
 	}
+	ao2_unlock(from);
+	ao2_unlock(to);
 
 	ao2_cleanup(forward);
 
@@ -596,6 +616,8 @@ struct stasis_forward *stasis_forward_cancel(struct stasis_forward *forward)
 struct stasis_forward *stasis_forward_all(struct stasis_topic *from_topic,
 	struct stasis_topic *to_topic)
 {
+	int res;
+	size_t idx;
 	RAII_VAR(struct stasis_forward *, forward, NULL, ao2_cleanup);
 
 	if (!from_topic || !to_topic) {
@@ -610,23 +632,19 @@ struct stasis_forward *stasis_forward_all(struct stasis_topic *from_topic,
 	forward->from_topic = ao2_bump(from_topic);
 	forward->to_topic = ao2_bump(to_topic);
 
-	{
-		SCOPED_AO2LOCK(lock, to_topic);
-		int res;
-
-		res = ast_vector_append(to_topic->upstream_topics, from_topic);
-		if (res != 0) {
-			return NULL;
-		}
+	topic_lock_both(to_topic, from_topic);
+	res = ast_vector_append(&to_topic->upstream_topics, from_topic);
+	if (res != 0) {
+		ao2_unlock(from_topic);
+		ao2_unlock(to_topic);
+		return NULL;
+	}
 
-		{
-			SCOPED_AO2LOCK(lock, from_topic);
-			size_t idx;
-			for (idx = 0; idx < ast_vector_size(to_topic->subscribers); ++idx) {
-				topic_add_subscription(from_topic, ast_vector_get(to_topic->subscribers, idx));
-			}
-		}
+	for (idx = 0; idx < ast_vector_size(&to_topic->subscribers); ++idx) {
+		topic_add_subscription(from_topic, ast_vector_get(&to_topic->subscribers, idx));
 	}
+	ao2_unlock(from_topic);
+	ao2_unlock(to_topic);
 
 	return ao2_bump(forward);
 }
diff --git a/main/stasis_message_router.c b/main/stasis_message_router.c
index 8c82decfe..7ed9bcb83 100644
--- a/main/stasis_message_router.c
+++ b/main/stasis_message_router.c
@@ -33,6 +33,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 
 #include "asterisk/astobj2.h"
 #include "asterisk/stasis_message_router.h"
+#include "asterisk/vector.h"
 
 /*! \internal */
 struct stasis_message_route {
@@ -44,19 +45,13 @@ struct stasis_message_route {
 	void *data;
 };
 
-struct route_table {
-	/*! Current number of entries in the route table */
-	size_t current_size;
-	/*! Allocated number of entires in the route table */
-	size_t max_size;
-	/*! The route table itself */
-	struct stasis_message_route routes[];
-};
+ast_vector(route_table, struct stasis_message_route);
 
-static struct stasis_message_route *table_find_route(struct route_table *table,
+static struct stasis_message_route *route_table_find(struct route_table *table,
 	struct stasis_message_type *message_type)
 {
 	size_t idx;
+	struct stasis_message_route *route;
 
 	/* While a linear search for routes may seem very inefficient, most
 	 * route tables have six routes or less. For such small data, it's
@@ -64,59 +59,74 @@ static struct stasis_message_route *table_find_route(struct route_table *table,
 	 * tables, then we can look into containers with more efficient
 	 * lookups.
 	 */
-	for (idx = 0; idx < table->current_size; ++idx) {
-		if (table->routes[idx].message_type == message_type) {
-			return &table->routes[idx];
+	for (idx = 0; idx < ast_vector_size(table); ++idx) {
+		route = ast_vector_get_addr(table, idx);
+		if (route->message_type == message_type) {
+			return route;
 		}
 	}
 
 	return NULL;
 }
 
-static int table_add_route(struct route_table **table_ptr,
+/*!
+ * \brief route_table comparator for ast_vector_remove_cmp_unordered()
+ *
+ * \param elem Element to compare against
+ * \param value Value to compare with the vector element.
+ *
+ * \return 0 if element does not match.
+ * \return Non-zero if element matches.
+ */
+#define ROUTE_TABLE_ELEM_CMP(elem, value) ((elem).message_type == (value))
+
+/*!
+ * \brief route_table vector element cleanup.
+ *
+ * \param elem Element to cleanup
+ *
+ * \return Nothing
+ */
+#define ROUTE_TABLE_ELEM_CLEANUP(elem)  ao2_cleanup((elem).message_type)
+
+static int route_table_remove(struct route_table *table,
+	struct stasis_message_type *message_type)
+{
+	return ast_vector_remove_cmp_unordered(table, message_type, ROUTE_TABLE_ELEM_CMP,
+		ROUTE_TABLE_ELEM_CLEANUP);
+}
+
+static int route_table_add(struct route_table *table,
 	struct stasis_message_type *message_type,
 	stasis_subscription_cb callback, void *data)
 {
-	struct route_table *table = *table_ptr;
-	struct stasis_message_route *route;
-
-	ast_assert(table_find_route(table, message_type) == NULL);
-
-	if (table->current_size + 1 > table->max_size) {
-		size_t new_max_size = table->max_size ? table->max_size * 2 : 1;
-		struct route_table *new_table = ast_realloc(table,
-			sizeof(*new_table) +
-			sizeof(new_table->routes[0]) * new_max_size);
-		if (!new_table) {
-			return -1;
-		}
-		*table_ptr = table = new_table;
-		table->max_size = new_max_size;
-	}
+	struct stasis_message_route route;
+	int res;
 
-	route = &table->routes[table->current_size++];
+	ast_assert(callback != NULL);
+	ast_assert(route_table_find(table, message_type) == NULL);
 
-	route->message_type = ao2_bump(message_type);
-	route->callback = callback;
-	route->data = data;
+	route.message_type = ao2_bump(message_type);
+	route.callback = callback;
+	route.data = data;
 
-	return 0;
+	res = ast_vector_append(table, route);
+	if (res) {
+		ROUTE_TABLE_ELEM_CLEANUP(route);
+	}
+	return res;
 }
 
-static int table_remove_route(struct route_table *table,
-	struct stasis_message_type *message_type)
+static void route_table_dtor(struct route_table *table)
 {
 	size_t idx;
+	struct stasis_message_route *route;
 
-	for (idx = 0; idx < table->current_size; ++idx) {
-		if (table->routes[idx].message_type == message_type) {
-			ao2_cleanup(message_type);
-			table->routes[idx] =
-				table->routes[--table->current_size];
-			return 0;
-		}
+	for (idx = 0; idx < ast_vector_size(table); ++idx) {
+		route = ast_vector_get_addr(table, idx);
+		ROUTE_TABLE_ELEM_CLEANUP(*route);
 	}
-	return -1;
+	ast_vector_free(table);
 }
 
 /*! \internal */
@@ -124,9 +134,9 @@ struct stasis_message_router {
 	/*! Subscription to the upstream topic */
 	struct stasis_subscription *subscription;
 	/*! Subscribed routes */
-	struct route_table *routes;
+	struct route_table routes;
 	/*! Subscribed routes for \ref stasis_cache_update messages */
-	struct route_table *cache_routes;
+	struct route_table cache_routes;
 	/*! Route of last resort */
 	struct stasis_message_route default_route;
 };
@@ -137,13 +147,11 @@ static void router_dtor(void *obj)
 
 	ast_assert(!stasis_subscription_is_subscribed(router->subscription));
 	ast_assert(stasis_subscription_is_done(router->subscription));
-	router->subscription = NULL;
 
-	ast_free(router->routes);
-	router->routes = NULL;
+	router->subscription = NULL;
 
-	ast_free(router->cache_routes);
-	router->cache_routes = NULL;
+	route_table_dtor(&router->routes);
+	route_table_dtor(&router->cache_routes);
 }
 
 static int find_route(
@@ -161,12 +169,12 @@ static int find_route(
 		/* Find a cache route */
 		struct stasis_cache_update *update =
 			stasis_message_data(message);
-		route = table_find_route(router->cache_routes, update->type);
+		route = route_table_find(&router->cache_routes, update->type);
 	}
 
 	if (route == NULL) {
 		/* Find a regular route */
-		route = table_find_route(router->routes, type);
+		route = route_table_find(&router->routes, type);
 	}
 
 	if (route == NULL && router->default_route.callback) {
@@ -201,6 +209,7 @@ static void router_dispatch(void *data,
 struct stasis_message_router *stasis_message_router_create(
 	struct stasis_topic *topic)
 {
+	int res;
 	RAII_VAR(struct stasis_message_router *, router, NULL, ao2_cleanup);
 
 	router = ao2_alloc(sizeof(*router), router_dtor);
@@ -208,13 +217,10 @@ struct stasis_message_router *stasis_message_router_create(
 		return NULL;
 	}
 
-	router->routes = ast_calloc(1, sizeof(*router->routes));
-	if (!router->routes) {
-		return NULL;
-	}
-
-	router->cache_routes = ast_calloc(1, sizeof(*router->cache_routes));
-	if (!router->cache_routes) {
+	res = 0;
+	res |= ast_vector_init(&router->routes, 0);
+	res |= ast_vector_init(&router->cache_routes, 0);
+	if (res) {
 		return NULL;
 	}
 
@@ -259,40 +265,78 @@ int stasis_message_router_add(struct stasis_message_router *router,
 	struct stasis_message_type *message_type,
 	stasis_subscription_cb callback, void *data)
 {
-	SCOPED_AO2LOCK(lock, router);
-	return table_add_route(&router->routes, message_type, callback, data);
+	int res;
+
+	ast_assert(router != NULL);
+
+	if (!message_type) {
+		/* Cannot route to NULL type. */
+		return -1;
+	}
+	ao2_lock(router);
+	res = route_table_add(&router->routes, message_type, callback, data);
+	ao2_unlock(router);
+	return res;
 }
 
 int stasis_message_router_add_cache_update(struct stasis_message_router *router,
 	struct stasis_message_type *message_type,
 	stasis_subscription_cb callback, void *data)
 {
-	SCOPED_AO2LOCK(lock, router);
-	return table_add_route(&router->cache_routes, message_type, callback, data);
+	int res;
+
+	ast_assert(router != NULL);
+
+	if (!message_type) {
+		/* Cannot cache a route to NULL type. */
+		return -1;
+	}
+	ao2_lock(router);
+	res = route_table_add(&router->cache_routes, message_type, callback, data);
+	ao2_unlock(router);
+	return res;
 }
 
 void stasis_message_router_remove(struct stasis_message_router *router,
 	struct stasis_message_type *message_type)
 {
-	SCOPED_AO2LOCK(lock, router);
-	table_remove_route(router->routes, message_type);
+	ast_assert(router != NULL);
+
+	if (!message_type) {
+		/* Cannot remove a NULL type. */
+		return;
+	}
+	ao2_lock(router);
+	route_table_remove(&router->routes, message_type);
+	ao2_unlock(router);
 }
 
 void stasis_message_router_remove_cache_update(
 	struct stasis_message_router *router,
 	struct stasis_message_type *message_type)
 {
-	SCOPED_AO2LOCK(lock, router);
-	table_remove_route(router->cache_routes, message_type);
+	ast_assert(router != NULL);
+
+	if (!message_type) {
+		/* Cannot remove a NULL type. */
+		return;
+	}
+	ao2_lock(router);
+	route_table_remove(&router->cache_routes, message_type);
+	ao2_unlock(router);
 }
 
 int stasis_message_router_set_default(struct stasis_message_router *router,
-				      stasis_subscription_cb callback,
-				      void *data)
+	stasis_subscription_cb callback,
+	void *data)
 {
-	SCOPED_AO2LOCK(lock, router);
+	ast_assert(router != NULL);
+	ast_assert(callback != NULL);
+
+	ao2_lock(router);
 	router->default_route.callback = callback;
 	router->default_route.data = data;
+	ao2_unlock(router);
 	/* While this implementation can never fail, it used to be able to */
 	return 0;
 }