sessiond: notification: use lttng_payload for communications
[lttng-tools.git] / include / lttng / notification / channel-internal.h
1 /*
2 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
3 *
4 * SPDX-License-Identifier: LGPL-2.1-only
5 *
6 */
7
8 #ifndef LTTNG_NOTIFICATION_CHANNEL_INTERNAL_H
9 #define LTTNG_NOTIFICATION_CHANNEL_INTERNAL_H
10
11 #include <lttng/notification/channel.h>
12 #include <common/macros.h>
13 #include <common/payload.h>
14 #include <stdint.h>
15 #include <stdbool.h>
16 #include <pthread.h>
17 #include <urcu/list.h>
18
19 /*
20 * Protocol version change log:
21 * - v1.0
22 * - Initial implementation of the notification channel protocol,
23 * - Supported conditions are LOW/HIGH buffer usage conditions,
24 * - v1.1
25 * - New condition type "LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE" added,
26 * - New condition type "LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING" added,
27 * - New condition type "LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED" added,
28 */
29 #define LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR 1
30 #define LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR 1
31
32 enum lttng_notification_channel_message_type {
33 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN = -1,
34 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE = 0,
35 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE = 1,
36 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE = 2,
37 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY = 3,
38 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION = 4,
39 LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED = 5,
40 };
41
42 struct lttng_notification_channel_message {
43 /* enum lttng_notification_channel_message_type */
44 int8_t type;
45 /* Size of the payload following this field. */
46 uint32_t size;
47 /* Number of FDs sent. */
48 uint32_t fds;
49 char payload[];
50 } LTTNG_PACKED;
51
52 struct lttng_notification_channel_command_handshake {
53 uint8_t major;
54 uint8_t minor;
55 } LTTNG_PACKED;
56
57 struct lttng_notification_channel_command_reply {
58 /* enum lttng_notification_channel_status */
59 int8_t status;
60 } LTTNG_PACKED;
61
62 struct pending_notification {
63 /* NULL means "notification dropped". */
64 struct lttng_notification *notification;
65 struct cds_list_head node;
66 };
67
68 /*
69 * The notification channel protocol is bidirectional and accommodates
70 * synchronous and asynchronous communication modes:
71 *
72 * - Synchronous: commands emitted by the client to which a reply is expected
73 * (e.g. subscribing/unsubscribing to conditions),
74 * - Asynchronous: notifications which are sent by the lttng_endpoint to the
75 * client as one of the subscribed condition has occurred.
76 *
77 * The nature of this hybrid communication mode means that asynchronous messages
78 * (e.g. notifications) may be interleaved between synchronous messages (e.g. a
79 * command and its reply).
80 *
81 * Notifications that are received between a command and its reply and enqueued
82 * in the pending_notifications list.
83 */
84 struct lttng_notification_channel {
85 pthread_mutex_t lock;
86 int socket;
87 struct {
88 /* Count of pending notifications. */
89 unsigned int count;
90 /* List of struct pending_notification. */
91 struct cds_list_head list;
92 } pending_notifications;
93 struct lttng_payload reception_payload;
94 /* Sessiond notification protocol version. */
95 struct {
96 bool set;
97 int8_t major, minor;
98 } version;
99 };
100
101 #endif /* LTTNG_NOTIFICATION_CHANNEL_INTERNAL_H */
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