X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=include%2Flttng%2Fnotification%2Fchannel-internal.hpp;fp=include%2Flttng%2Fnotification%2Fchannel-internal.hpp;h=3364704eed12ccad98f410876970df69d92c3edd;hp=0000000000000000000000000000000000000000;hb=c9e313bc594f40a86eed237dce222c0fc99c957f;hpb=4878de5c7deb512bbdac4fdfc498907efa06fb7c

diff --git a/include/lttng/notification/channel-internal.hpp b/include/lttng/notification/channel-internal.hpp
new file mode 100644
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--- /dev/null
+++ b/include/lttng/notification/channel-internal.hpp
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ */
+
+#ifndef LTTNG_NOTIFICATION_CHANNEL_INTERNAL_H
+#define LTTNG_NOTIFICATION_CHANNEL_INTERNAL_H
+
+#include <lttng/notification/channel.h>
+#include <common/macros.hpp>
+#include <common/payload.hpp>
+#include <stdint.h>
+#include <stdbool.h>
+#include <pthread.h>
+#include <urcu/list.h>
+
+/*
+ * Protocol version change log:
+ * - v1.0
+ *   - Initial implementation of the notification channel protocol,
+ *   - Supported conditions are LOW/HIGH buffer usage conditions,
+ * - v1.1
+ *   - New condition type "LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE" added,
+ *   - New condition type "LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING" added,
+ *   - New condition type "LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED" added,
+ */
+#define LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR 1
+#define LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR 1
+
+enum lttng_notification_channel_message_type {
+	LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN = -1,
+	LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE = 0,
+	LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE = 1,
+	LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE = 2,
+	LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY = 3,
+	LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION = 4,
+	LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED = 5,
+};
+
+struct lttng_notification_channel_message {
+	/* enum lttng_notification_channel_message_type */
+	int8_t type;
+	/* Size of the payload following this field. */
+	uint32_t size;
+	/* Number of FDs sent. */
+	uint32_t fds;
+	char payload[];
+} LTTNG_PACKED;
+
+struct lttng_notification_channel_command_handshake {
+	uint8_t major;
+	uint8_t minor;
+} LTTNG_PACKED;
+
+struct lttng_notification_channel_command_reply {
+	/* enum lttng_notification_channel_status */
+	int8_t status;
+} LTTNG_PACKED;
+
+struct pending_notification {
+	/* NULL means "notification dropped". */
+	struct lttng_notification *notification;
+	struct cds_list_head node;
+};
+
+/*
+ * The notification channel protocol is bidirectional and accommodates
+ * synchronous and asynchronous communication modes:
+ *
+ *   - Synchronous: commands emitted by the client to which a reply is expected
+ *     (e.g. subscribing/unsubscribing to conditions),
+ *   - Asynchronous: notifications which are sent by the lttng_endpoint to the
+ *     client as one of the subscribed condition has occurred.
+ *
+ * The nature of this hybrid communication mode means that asynchronous messages
+ * (e.g. notifications) may be interleaved between synchronous messages (e.g. a
+ * command and its reply).
+ *
+ * Notifications that are received between a command and its reply and enqueued
+ * in the pending_notifications list.
+ */
+struct lttng_notification_channel {
+	pthread_mutex_t lock;
+	int socket;
+	struct {
+		/* Count of pending notifications. */
+		unsigned int count;
+		/* List of struct pending_notification. */
+		struct cds_list_head list;
+	} pending_notifications;
+	struct lttng_payload reception_payload;
+	/* Sessiond notification protocol version. */
+	struct {
+		bool set;
+		int8_t major, minor;
+	} version;
+};
+
+#endif /* LTTNG_NOTIFICATION_CHANNEL_INTERNAL_H */