Merge "pjsip_distributor.c: Fix deadlock with TCP type transports."

1 files changed, 174 insertions, 42 deletions

diff --git a/res/res_pjsip/pjsip_distributor.c b/res/res_pjsip/pjsip_distributor.c
index 2c9bcbf6e..cf1b04a8b 100644
--- a/res/res_pjsip/pjsip_distributor.c
+++ b/res/res_pjsip/pjsip_distributor.c
@@ -150,62 +150,189 @@ static struct ast_taskprocessor *find_request_serializer(pjsip_rx_data *rdata)
 
 /*! Dialog-specific information the distributor uses */
 struct distributor_dialog_data {
+	/*! dialog_associations ao2 container key */
+	pjsip_dialog *dlg;
 	/*! Serializer to distribute tasks to for this dialog */
 	struct ast_taskprocessor *serializer;
 	/*! Endpoint associated with this dialog */
 	struct ast_sip_endpoint *endpoint;
 };
 
+#define DIALOG_ASSOCIATIONS_BUCKETS 251
+
+static struct ao2_container *dialog_associations;
+
 /*!
  * \internal
+ * \brief Compute a hash value on an arbitrary buffer.
+ * \since 13.17.0
+ *
+ * \param[in] pos The buffer to add to the hash
+ * \param[in] len The buffer length to add to the hash
+ * \param[in] hash The hash value to add to
+ *
+ * \details
+ * This version of the function is for when you need to compute a
+ * hash of more than one buffer.
+ *
+ * This famous hash algorithm was written by Dan Bernstein and is
+ * commonly used.
  *
- * \note Call this with the dialog locked
+ * \sa http://www.cse.yorku.ca/~oz/hash.html
  */
-static struct distributor_dialog_data *distributor_dialog_data_alloc(pjsip_dialog *dlg)
+static int buf_hash_add(const char *pos, size_t len, int hash)
 {
-	struct distributor_dialog_data *dist;
+	while (len--) {
+		hash = hash * 33 ^ *pos++;
+	}
+
+	return hash;
+}
+
+/*!
+ * \internal
+ * \brief Compute a hash value on an arbitrary buffer.
+ * \since 13.17.0
+ *
+ * \param[in] pos The buffer to add to the hash
+ * \param[in] len The buffer length to add to the hash
+ *
+ * \details
+ * This version of the function is for when you need to compute a
+ * hash of more than one buffer.
+ *
+ * This famous hash algorithm was written by Dan Bernstein and is
+ * commonly used.
+ *
+ * \sa http://www.cse.yorku.ca/~oz/hash.html
+ */
+static int buf_hash(const char *pos, size_t len)
+{
+	return buf_hash_add(pos, len, 5381);
+}
+
+static int dialog_associations_hash(const void *obj, int flags)
+{
+	const struct distributor_dialog_data *object;
+	union {
+		const pjsip_dialog *dlg;
+		const char buf[sizeof(pjsip_dialog *)];
+	} key;
+
+	switch (flags & OBJ_SEARCH_MASK) {
+	case OBJ_SEARCH_KEY:
+		key.dlg = obj;
+		break;
+	case OBJ_SEARCH_OBJECT:
+		object = obj;
+		key.dlg = object->dlg;
+		break;
+	default:
+		/* Hash can only work on something with a full key. */
+		ast_assert(0);
+		return 0;
+	}
+	return ast_str_hash_restrict(buf_hash(key.buf, sizeof(key.buf)));
+}
 
-	dist = PJ_POOL_ZALLOC_T(dlg->pool, struct distributor_dialog_data);
-	pjsip_dlg_set_mod_data(dlg, distributor_mod.id, dist);
+static int dialog_associations_cmp(void *obj, void *arg, int flags)
+{
+	const struct distributor_dialog_data *object_left = obj;
+	const struct distributor_dialog_data *object_right = arg;
+	const pjsip_dialog *right_key = arg;
+	int cmp = 0;
 
-	return dist;
+	switch (flags & OBJ_SEARCH_MASK) {
+	case OBJ_SEARCH_OBJECT:
+		right_key = object_right->dlg;
+		/* Fall through */
+	case OBJ_SEARCH_KEY:
+		if (object_left->dlg == right_key) {
+			cmp = CMP_MATCH;
+		}
+		break;
+	case OBJ_SEARCH_PARTIAL_KEY:
+		/* There is no such thing for this container. */
+		ast_assert(0);
+		break;
+	default:
+		cmp = 0;
+		break;
+	}
+	return cmp;
 }
 
 void ast_sip_dialog_set_serializer(pjsip_dialog *dlg, struct ast_taskprocessor *serializer)
 {
 	struct distributor_dialog_data *dist;
-	SCOPED_LOCK(lock, dlg, pjsip_dlg_inc_lock, pjsip_dlg_dec_lock);
 
-	dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
+	ao2_wrlock(dialog_associations);
+	dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY | OBJ_NOLOCK);
 	if (!dist) {
-		dist = distributor_dialog_data_alloc(dlg);
+		if (serializer) {
+			dist = ao2_alloc(sizeof(*dist), NULL);
+			if (dist) {
+				dist->dlg = dlg;
+				dist->serializer = serializer;
+				ao2_link_flags(dialog_associations, dist, OBJ_NOLOCK);
+				ao2_ref(dist, -1);
+			}
+		}
+	} else {
+		ao2_lock(dist);
+		dist->serializer = serializer;
+		if (!dist->serializer && !dist->endpoint) {
+			ao2_unlink_flags(dialog_associations, dist, OBJ_NOLOCK);
+		}
+		ao2_unlock(dist);
+		ao2_ref(dist, -1);
 	}
-	dist->serializer = serializer;
+	ao2_unlock(dialog_associations);
 }
 
 void ast_sip_dialog_set_endpoint(pjsip_dialog *dlg, struct ast_sip_endpoint *endpoint)
 {
 	struct distributor_dialog_data *dist;
-	SCOPED_LOCK(lock, dlg, pjsip_dlg_inc_lock, pjsip_dlg_dec_lock);
 
-	dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
+	ao2_wrlock(dialog_associations);
+	dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY | OBJ_NOLOCK);
 	if (!dist) {
-		dist = distributor_dialog_data_alloc(dlg);
+		if (endpoint) {
+			dist = ao2_alloc(sizeof(*dist), NULL);
+			if (dist) {
+				dist->dlg = dlg;
+				dist->endpoint = endpoint;
+				ao2_link_flags(dialog_associations, dist, OBJ_NOLOCK);
+				ao2_ref(dist, -1);
+			}
+		}
+	} else {
+		ao2_lock(dist);
+		dist->endpoint = endpoint;
+		if (!dist->serializer && !dist->endpoint) {
+			ao2_unlink_flags(dialog_associations, dist, OBJ_NOLOCK);
+		}
+		ao2_unlock(dist);
+		ao2_ref(dist, -1);
 	}
-	dist->endpoint = endpoint;
+	ao2_unlock(dialog_associations);
 }
 
 struct ast_sip_endpoint *ast_sip_dialog_get_endpoint(pjsip_dialog *dlg)
 {
 	struct distributor_dialog_data *dist;
-	SCOPED_LOCK(lock, dlg, pjsip_dlg_inc_lock, pjsip_dlg_dec_lock);
+	struct ast_sip_endpoint *endpoint;
 
-	dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
-	if (!dist || !dist->endpoint) {
-		return NULL;
+	dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY);
+	if (dist) {
+		ao2_lock(dist);
+		endpoint = ao2_bump(dist->endpoint);
+		ao2_unlock(dist);
+		ao2_ref(dist, -1);
+	} else {
+		endpoint = NULL;
 	}
-	ao2_ref(dist->endpoint, +1);
-	return dist->endpoint;
+	return endpoint;
 }
 
 static pjsip_dialog *find_dialog(pjsip_rx_data *rdata)
@@ -237,7 +364,7 @@ static pjsip_dialog *find_dialog(pjsip_rx_data *rdata)
 			pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, &pjsip_cancel_method) ||
 			rdata->msg_info.to->tag.slen != 0) {
 		dlg = pjsip_ua_find_dialog(&rdata->msg_info.cid->id, local_tag,
-				remote_tag, PJ_TRUE);
+				remote_tag, PJ_FALSE);
 		if (dlg) {
 			return dlg;
 		}
@@ -275,11 +402,6 @@ static pjsip_dialog *find_dialog(pjsip_rx_data *rdata)
 	pj_mutex_unlock(tsx->mutex);
 #endif
 
-	if (!dlg) {
-		return NULL;
-	}
-
-	pjsip_dlg_inc_lock(dlg);
 	return dlg;
 }
 
@@ -302,16 +424,7 @@ static pjsip_dialog *find_dialog(pjsip_rx_data *rdata)
  */
 static int pjstr_hash_add(pj_str_t *str, int hash)
 {
-	size_t len;
-	const char *pos;
-
-	len = pj_strlen(str);
-	pos = pj_strbuf(str);
-	while (len--) {
-		hash = hash * 33 ^ *pos++;
-	}
-
-	return hash;
+	return buf_hash_add(pj_strbuf(str), pj_strlen(str), hash);
 }
 
 /*!
@@ -350,7 +463,7 @@ struct ast_taskprocessor *ast_sip_get_distributor_serializer(pjsip_rx_data *rdat
 	/* Compute the hash from the SIP message call-id and remote-tag */
 	hash = pjstr_hash(&rdata->msg_info.cid->id);
 	hash = pjstr_hash_add(remote_tag, hash);
-	hash = abs(hash);
+	hash = ast_str_hash_restrict(hash);
 
 	serializer = ao2_bump(distributor_pool[hash % ARRAY_LEN(distributor_pool)]);
 	if (serializer) {
@@ -385,17 +498,18 @@ static pj_bool_t distributor(pjsip_rx_data *rdata)
 
 	dlg = find_dialog(rdata);
 	if (dlg) {
-		ast_debug(3, "Searching for serializer on dialog %s for %s\n",
+		ast_debug(3, "Searching for serializer associated with dialog %s for %s\n",
 			dlg->obj_name, pjsip_rx_data_get_info(rdata));
-		dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
+		dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY);
 		if (dist) {
+			ao2_lock(dist);
 			serializer = ao2_bump(dist->serializer);
+			ao2_unlock(dist);
 			if (serializer) {
-				ast_debug(3, "Found serializer %s on dialog %s\n",
+				ast_debug(3, "Found serializer %s associated with dialog %s\n",
 					ast_taskprocessor_name(serializer), dlg->obj_name);
 			}
 		}
-		pjsip_dlg_dec_lock(dlg);
 	}
 
 	if (serializer) {
@@ -417,6 +531,7 @@ static pj_bool_t distributor(pjsip_rx_data *rdata)
 		/* We have a BYE or CANCEL request without a serializer. */
 		pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata,
 			PJSIP_SC_CALL_TSX_DOES_NOT_EXIST, NULL, NULL, NULL);
+		ao2_cleanup(dist);
 		return PJ_TRUE;
 	} else {
 		if (ast_taskprocessor_alert_get()) {
@@ -431,6 +546,7 @@ static pj_bool_t distributor(pjsip_rx_data *rdata)
 			 */
 			ast_debug(3, "Taskprocessor overload alert: Ignoring '%s'.\n",
 				pjsip_rx_data_get_info(rdata));
+			ao2_cleanup(dist);
 			return PJ_TRUE;
 		}
 
@@ -438,10 +554,17 @@ static pj_bool_t distributor(pjsip_rx_data *rdata)
 		serializer = ast_sip_get_distributor_serializer(rdata);
 	}
 
-	pjsip_rx_data_clone(rdata, 0, &clone);
+	if (pjsip_rx_data_clone(rdata, 0, &clone) != PJ_SUCCESS) {
+		ast_taskprocessor_unreference(serializer);
+		ao2_cleanup(dist);
+		return PJ_TRUE;
+	}
 
 	if (dist) {
+		ao2_lock(dist);
 		clone->endpt_info.mod_data[endpoint_mod.id] = ao2_bump(dist->endpoint);
+		ao2_unlock(dist);
+		ao2_cleanup(dist);
 	}
 
 	if (ast_sip_push_task(serializer, distribute, clone)) {
@@ -1088,6 +1211,14 @@ int ast_sip_initialize_distributor(void)
 		return -1;
 	}
 
+	dialog_associations = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_RWLOCK, 0,
+		DIALOG_ASSOCIATIONS_BUCKETS, dialog_associations_hash, NULL,
+		dialog_associations_cmp);
+	if (!dialog_associations) {
+		ast_sip_destroy_distributor();
+		return -1;
+	}
+
 	if (distributor_pool_setup()) {
 		ast_sip_destroy_distributor();
 		return -1;
@@ -1166,5 +1297,6 @@ void ast_sip_destroy_distributor(void)
 
 	distributor_pool_shutdown();
 
+	ao2_cleanup(dialog_associations);
 	ao2_cleanup(unidentified_requests);
 }