ipc_protocol.h

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// Copyright 2020-2024 Collabora, Ltd.
// Copyright 2025-2026, NVIDIA CORPORATION.
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  Common protocol definition.
 * @author Pete Black <pblack@collabora.com>
 * @author Jakob Bornecrantz <jakob@collabora.com>
 * @author Korcan Hussein <korcan.hussein@collabora.com>
 * @ingroup ipc_shared
 */
 
#pragma once
 
#include "xrt/xrt_limits.h"
#include "xrt/xrt_compiler.h"
#include "xrt/xrt_compositor.h"
#include "xrt/xrt_results.h"
#include "xrt/xrt_defines.h"
#include "xrt/xrt_future.h"
#include "xrt/xrt_system.h"
#include "xrt/xrt_session.h"
#include "xrt/xrt_instance.h"
#include "xrt/xrt_compositor.h"
#include "xrt/xrt_device.h"
#include "xrt/xrt_space.h"
#include "xrt/xrt_tracking.h"
#include "xrt/xrt_config_build.h"
 
#include <assert.h>
#include <sys/types.h>
 
 
#define IPC_CRED_SIZE 1    // auth not implemented
#define IPC_BUF_SIZE 2048  // must be >= largest message length in bytes
#define IPC_MAX_VIEWS 8    // max views we will return configs for
#define IPC_MAX_FORMATS 32 // max formats our server-side compositor supports
#define IPC_MAX_DEVICES 8  // max number of devices we will map using shared mem
#define IPC_MAX_LAYERS XRT_MAX_LAYERS
#define IPC_MAX_SLOTS 128
#define IPC_MAX_CLIENTS 32
#define IPC_MAX_RAW_VIEWS 32 // Max views that we can get, artificial limit.
#define IPC_EVENT_QUEUE_SIZE 32
 
 
// example: v21.0.0-560-g586d33b5
#define IPC_VERSION_NAME_LEN 64
 
#if defined(XRT_OS_WINDOWS) && !defined(XRT_ENV_MINGW)
typedef int pid_t;
#endif
 
// Define the format to use to print a pid type
#if defined(XRT_ENV_MINGW)
// On Mingw64, this is an int64, aka a signed long long
#define PID_T_FMT "%lli"
#else
// On Linux and 'native' Windows, this is an int
#define PID_T_FMT "%d"
#endif
 
/*
 *
 * Shared memory structs.
 *
 */
 
/*!
 * Information about a device in the device list.
 *
 * @ingroup ipc
 */
struct ipc_tracking_origin_list_entry
{
        //! Tracking origin ID
        uint32_t id;
};
 
/*!
 * A list of the current tracking origins.
 *
 * @ingroup ipc
 */
struct ipc_tracking_origin_list
{
        //! Number of tracking origins.
        uint32_t origin_count;
 
        //! Compact list of tracking origins.
        struct ipc_tracking_origin_list_entry origins[XRT_SYSTEM_MAX_DEVICES];
};
 
/*!
 * A tracking in the shared memory area.
 *
 * @ingroup ipc
 */
struct ipc_tracking_origin_info
{
        //! For debugging.
        char name[XRT_TRACKING_NAME_LEN];
 
        //! What can the state tracker expect from this tracking system.
        enum xrt_tracking_type type;
 
        //! Initial offset of the tracking origin.
        struct xrt_pose offset;
};
 
/*!
 * Information about a device in the device list.
 *
 * @ingroup ipc
 */
struct ipc_device_list_entry
{
        //! Device ID
        uint32_t id;
 
        //! Device type
        enum xrt_device_type device_type;
};
 
/*!
 * List of devices available on the server.
 *
 * @ingroup ipc
 */
struct ipc_device_list
{
        //! Number of devices
        uint32_t device_count;
 
        //! Device entries
        struct ipc_device_list_entry devices[XRT_SYSTEM_MAX_DEVICES];
};
 
/*!
 * Device information sent over IPC.
 *
 * Followed by varlen data containing:
 * - An array of input_count * enum xrt_input_name
 * - An array of output_count * enum xrt_output_name
 * - An array of binding_profile_count * struct ipc_binding_profile_info
 * - An array of total_input_pair_count * struct xrt_binding_input_pair
 * - An array of total_output_pair_count * struct xrt_binding_output_pair
 *
 * @ingroup ipc
 */
struct ipc_device_info
{
        //! Enum identifier of the device.
        enum xrt_device_name name;
        enum xrt_device_type device_type;
 
        //! Which tracking system origin is this device attached to.
        uint32_t tracking_origin_id;
 
        //! A string describing the device.
        char str[XRT_DEVICE_NAME_LEN];
 
        //! A unique identifier. Persistent across configurations, if possible.
        char serial[XRT_DEVICE_NAME_LEN];
 
        //! Number of binding profiles in varlen data.
        uint32_t binding_profile_count;
 
        //! Total number of input pairs in varlen data (across all binding profiles).
        uint32_t total_input_pair_count;
 
        //! Total number of output pairs in varlen data (across all binding profiles).
        uint32_t total_output_pair_count;
 
        //! Number of inputs.
        uint32_t input_count;
 
        //! Number of outputs.
        uint32_t output_count;
 
        //! The supported fields.
        struct xrt_device_supported supported;
};
 
/*!
 * A binding in the shared memory area.
 *
 * @ingroup ipc
 */
struct ipc_binding_profile_info
{
        enum xrt_device_name name;
 
        //! Offset into the array of pairs where this input bindings starts.
        uint32_t first_input_index;
        //! Number of inputs.
        uint32_t input_count;
 
        //! Offset into the array of pairs where this output bindings starts.
        uint32_t first_output_index;
        //! Number of outputs.
        uint32_t output_count;
};
 
/*!
 * Data for a single composition layer.
 *
 * Similar in function to @ref comp_layer
 *
 * @ingroup ipc
 */
struct ipc_layer_entry
{
        //! @todo what is this used for?
        uint32_t xdev_id;
 
        /*!
         * Up to two indices of swapchains to use.
         *
         * How many are actually used depends on the value of @p data.type
         */
        uint32_t swapchain_ids[XRT_MAX_VIEWS * 2];
 
        /*!
         * All basic (trivially-serializable) data associated with a layer,
         * aside from which swapchain(s) are used.
         */
        struct xrt_layer_data data;
};
 
/*!
 * Render state for a single client, including all layers.
 *
 * @ingroup ipc
 */
struct ipc_layer_slot
{
        struct xrt_layer_frame_data data;
        uint32_t layer_count;
        struct ipc_layer_entry layers[IPC_MAX_LAYERS];
};
 
/*!
 * A big struct that contains all data that is shared to a client, no pointers
 * allowed in this. To get the inputs of a device you go:
 *
 * ```C++
 * struct xrt_input *
 * helper(struct ipc_shared_memory *ism, uint32_t device_id, uint32_t input)
 * {
 *      uint32_t index = ism->isdevs[device_id]->first_input_index + input;
 *      return &ism->inputs[index];
 * }
 * ```
 *
 * @ingroup ipc
 */
struct ipc_shared_memory
{
        /*!
         * The git revision of the service, used by clients to detect version mismatches.
         */
        char u_git_tag[IPC_VERSION_NAME_LEN];
 
        /*!
         * Various roles for the devices.
         */
        struct
        {
                int32_t head;
                int32_t eyes;
                int32_t face;
                int32_t body;
 
                struct
                {
                        struct
                        {
                                int32_t left;
                                int32_t right;
                        } unobstructed;
 
                        struct
                        {
                                int32_t left;
                                int32_t right;
                        } conforming;
                } hand_tracking;
        } roles;
 
        struct
        {
                struct
                {
                        /*!
                         * Pixel properties of this display, not in absolute
                         * screen coordinates that the compositor sees. So
                         * before any rotation is applied by xrt_view::rot.
                         *
                         * The xrt_view::display::w_pixels &
                         * xrt_view::display::h_pixels become the recommended
                         * image size for this view.
                         *
                         * @todo doesn't account for overfill for timewarp or
                         * distortion?
                         */
                        struct
                        {
                                uint32_t w_pixels;
                                uint32_t h_pixels;
                        } display;
                } views[2];
                // view count
                uint32_t view_count;
                enum xrt_blend_mode blend_modes[XRT_MAX_DEVICE_BLEND_MODES];
                uint32_t blend_mode_count;
        } hmd;
 
        struct ipc_layer_slot slots[IPC_MAX_SLOTS];
 
        uint64_t startup_timestamp;
        struct xrt_plane_detector_begin_info_ext plane_begin_info_ext;
};
 
/*!
 * Initial info from a client when it connects.
 */
struct ipc_client_description
{
        pid_t pid;
        struct xrt_application_info info;
};
 
struct ipc_client_list
{
        uint32_t ids[IPC_MAX_CLIENTS];
        uint32_t id_count;
};
 
/*!
 * Which types of IO to block for a client.
 *
 * @ingroup ipc
 */
struct ipc_client_io_blocks
{
        bool block_poses;
        bool block_hand_tracking;
        bool block_inputs;
        bool block_outputs;
};
 
/*!
 * State for a connected application.
 *
 * @ingroup ipc
 */
struct ipc_app_state
{
        // Stable and unique ID of the client, only unique within this instance.
        uint32_t id;
 
        bool primary_application;
        bool session_active;
        bool session_visible;
        bool session_focused;
        bool session_overlay;
        struct ipc_client_io_blocks io_blocks;
        uint32_t z_order;
        pid_t pid;
        struct xrt_application_info info;
};
 
 
/*!
 * Arguments for creating swapchains from native images.
 */
struct ipc_arg_swapchain_from_native
{
        uint32_t sizes[XRT_MAX_SWAPCHAIN_IMAGES];
};
 
/*!
 * Arguments for xrt_device::get_view_poses with two views.
 */
struct ipc_info_get_view_poses_2
{
        struct xrt_fov fovs[XRT_MAX_VIEWS];
        struct xrt_pose poses[XRT_MAX_VIEWS];
        struct xrt_space_relation head_relation;
};
 
struct ipc_pcm_haptic_buffer
{
        uint32_t num_samples;
        float sample_rate;
        bool append;
};