//---------------------------------------------------------------------------
//
// SCSI Target Emulator PiSCSI
// for Raspberry Pi
//
// Copyright (C) 2021-2022 Uwe Seimet
//
//---------------------------------------------------------------------------

//
// Each piscsi message sent to the piscsi server is preceded by the magic string "RASCSI".
// A message starts with a little endian 32 bit header which contains the protobuf message size.
// Unless explicitly specified the order of repeated data returned is undefined.
// All operations accept an optional access token, specified by the "token" parameter.
// All operations also accept an optional locale, specified with the "locale" parameter. If there is
// a localized error message piscsi returns it, with English being the fallback language.
//

syntax = "proto3";

package piscsi_interface;

// The available device types
enum PbDeviceType {
    UNDEFINED = 0;
    // Non-removable SASI drive, not supported anymore
    SAHD = 1 [deprecated = true];
    // Non-removable SCSI drive
    SCHD = 2;
    // Removable SCSI drive
    SCRM = 3;
    // Magnoto-Optical drive
    SCMO = 4;
    // CD-ROM drive
    SCCD = 5;
    // Network bridge
    SCBR = 6;
    // DaynaPort network adapter
    SCDP = 7;
    // Host services device
    SCHS = 8;
    // Printer device
    SCLP = 9;
    // PowerView device
    SCPV = 10;
}

// piscsi remote operations, returning PbResult
enum PbOperation {
    NO_OPERATION = 0;

    // Attach devices and return the new device list (PbDevicesInfo)
    // Parameters (depending on the device type):
    //   "file": The filename relative to the default image folder
    //   "interface": A prioritized comma-separated list of interfaces to create a network bridge for
    //   "inet": The IP address and netmask for the network bridge
    //   "cmd": The command to be used for printing, with "%f" as file placeholder
    ATTACH = 1;

    // Detach a device and return the new device list (PbDevicesInfo)
    // Detaches all LUNs of that device which are equal to or higher than the LUN specified.
    DETACH = 2;

    // Detach all devices, does not require a device list
    DETACH_ALL = 3;

    // Start device
    START = 4;

    // Stop device, e.g. park drive
    STOP = 5;

    // Insert medium
    // Parameters:
    //   "file": The filename, relative to the default image folder
    INSERT = 6;

    // Eject medium
    EJECT = 7;

    // Write-protect medium (not possible for read-only media)
    PROTECT = 8;

    // Make medium writable (not possible for read-only media)
    UNPROTECT = 9;

    // Gets the server information (PbServerInfo). Calling this operation should be avoided because it
    // may return a lot of data. More specific other operations should be used instead.
    // Parameters:
    //   "folder_pattern": Optional filter, only folder names containing the case-insensitive pattern are returned
    //   "file_pattern": Optional filter, only filenames containing the case-insensitive pattern are returned
    SERVER_INFO = 10;

    // Get piscsi server version (PbVersionInfo)
    VERSION_INFO = 11;

    // Get information on attached devices (PbDevicesInfo)
    // Returns data for all attached devices if the device list is empty.
    DEVICES_INFO = 12;

    // Get device properties by device type (PbDeviceTypesInfo)
    DEVICE_TYPES_INFO = 13;

    // Get information on available image files in the default image folder (PbImageFilesInfo)
    // Parameters:
    //   "folder_pattern": Optional filter, only folder names containing the case-insensitive pattern are returned
    //   "file_pattern": Optional filter, only filenames containing the case-insensitive pattern are returned
    DEFAULT_IMAGE_FILES_INFO = 14;
    
    // Get information on an image file (not necessarily in the default image folder).
    // Parameters:
    //   "file": The filename. Either an absolute path or a path relative to the default image folder.
    IMAGE_FILE_INFO = 15;

    // Get information on the available log levels and the current log level (PbLogLevelInfo)
    LOG_LEVEL_INFO = 16;

    // Get the names of the available network interfaces (PbNetworkInterfacesInfo)
    // Only lists interfaces that are up.
    NETWORK_INTERFACES_INFO = 17;
    
    // Get the mapping of extensions to device types (PbMappingInfo)
    MAPPING_INFO = 18;
    
    // Get the list of reserved device IDs (PbReservedIdsInfo)
    RESERVED_IDS_INFO = 19;

    // Set the default folder for image files. This folder must be located in /home.
    // Parameters:
    //   "folder": The path of the default folder, relative to the user's home folder if relative.
    DEFAULT_FOLDER = 20;

    // Set the log level.
    // Parameters:
    //   "level": The new log level
    LOG_LEVEL = 21;

    // Block IDs from being used, usually the IDs of the initiators (computers) in the SCSI chain.
    // Parameters:
    //   "ids": A comma-separated list of IDs to reserve, or an empty string in order not to reserve any ID.
    RESERVE_IDS = 22;
    
    // Shut down the piscsi process or shut down/reboot the Pi
    // Parameters:
    //   "mode": The shutdown mode, one of
    //     "rascsi": Shuts down the piscsi process ("rascsi" instead of "piscsi" for backwards compatibility)
    //     "system": Shuts down the Pi
    //     "reboot": Reboots the Pi
    SHUT_DOWN = 23;

    // Create an image file. The image file must not yet exist.
    // Parameters:
    //   "file": The filename, relative to the default image folder
    //   "size": The file size in bytes, must be a multiple of 512
    //   "read_only": Optional, "true" (case-insensitive) in order to create a read-only file
    CREATE_IMAGE = 24;

    // Delete an image file.
    // Parameters:
    //    "file": The filename, relative to the default image folder.
    DELETE_IMAGE = 25;

    // Rename/Move an image file.
    // Parameters:
    //   "from": The old filename, relative to the default image folder
    //   "to": The new filename, relative to the default image folder
    // The new filename must not yet exist.
    RENAME_IMAGE = 26;

    // Copy an image file.
    // Parameters:
    //   "from": The source filename, relative to the default image folder
    //   "to": The destination filename, relative to the default image folder
    //   "read_only": Optional, "true" (case-insensitive) in order to create a read-only file
    // The destination filename must not yet exist.
    COPY_IMAGE = 27;
    
    // Write-protect an image file.
    // Parameters:
    //  "file": The filename, relative to the default image folder
    PROTECT_IMAGE = 28;

    // Make an image file writable.
    // Parameters:
    //   "file": The filename, relative to the default image folder
    UNPROTECT_IMAGE = 29;

    // Check whether an authentication token is valid. A client can use this operation in order to
    // find out whether piscsi authentication is enable or to use piscsi authentication for securing
    // client-internal operations.
    CHECK_AUTHENTICATION = 30;

    // Get operation meta data (PbOperationInfo)
    OPERATION_INFO = 31;
}

// The operation parameter meta data. The parameter data type is provided by the protobuf API.
message PbOperationParameter {
    string name = 1;
    // Optional short description
    string description = 2;
    // There is no specific set of permitted values if empty
    repeated string permitted_values = 3;
    // Optional default value
    string default_value = 4;
    // True if this parameter is mandatory
    bool is_mandatory = 5;
}

// The list of parameters supported by an operation
message PbOperationMetaData {
    // The operation name at the time the server-side protobuf code was generated.
    string server_side_name = 1;
    // Optional short description
    string description = 2;
    repeated PbOperationParameter parameters = 3;
}

// Mapping of operations to their ordinals
message PbOperationInfo {
    map<int32, PbOperationMetaData> operations = 1;
}

// piscsi special purpose error codes for cases where a textual error message may not be not sufficient.
// The client may react on this code, e.g. by prompting the user for an authentication token.
enum PbErrorCode {
    // No error code available
    NO_ERROR_CODE = 0;
    // The client sent an operation code not supported by this server
    UNKNOWN_OPERATION = 1;
    // Authentication/Authorization error
    UNAUTHORIZED = 2;
}

// The supported file extensions mapped to their respective device types
message PbMappingInfo {
    map<string, PbDeviceType> mapping = 1;
}

// The properties supported by a device
message PbDeviceProperties {
     // Read-only media (e.g. CD-ROMs) are not protectable but permanently read-only
    bool read_only = 1;
    // Medium can be write-protected
    bool protectable = 2;
    // Device can be stopped, e.g. parked
    bool stoppable = 3;
    // Medium can be removed
    bool removable = 4;
    // Medium can be locked
    bool lockable = 5;
    // Device supports image file as a parameter
    bool supports_file = 6;
    // Device supports parameters other than a filename
    bool supports_params = 7;
    // List of default parameters, if any (requires supports_params to be true)
    map<string, string> default_params = 8;
    // LUN numbers this device can have, usually 32
    int32 luns = 9;
    // Unordered list of permitted block sizes in bytes, empty if the block size is not configurable
    repeated uint32 block_sizes = 10;
}

// The status of a device, only meaningful if the respective feature is supported
message PbDeviceStatus {
    // Medium is write-protected
    bool protected = 1;
    // Device is stopped, e.g. parked
    bool stopped = 2;
    // Medium is removed
    bool removed = 3;
    // Medium is locked
    bool locked = 4;
}

// Device properties by device type. (Note that a protobuf map cannot be used because enums cannot be map keys.)
message PbDeviceTypeProperties {
    PbDeviceType type = 1;
    PbDeviceProperties properties = 2;
}

message PbDeviceTypesInfo {
    repeated PbDeviceTypeProperties properties = 1;
}

// The image file data
message PbImageFile {
    string name = 1;
    // The assumed device type, based on the filename extension
    PbDeviceType type = 2;
    // The file size in bytes, 0 for block devices
    uint64 size = 3;
    bool read_only = 4;
}

// The default image folder and the image files it contains
message PbImageFilesInfo {
    string default_image_folder = 1;
    repeated PbImageFile image_files = 2;
    // The maximum nesting depth, configured with the -R option
    int32 depth = 3;
}

// Log level information
message PbLogLevelInfo {
    // List of available log levels, ordered by increasing by severity
    repeated string log_levels = 2;
    string current_log_level = 3;
}

// The network interfaces information
message PbNetworkInterfacesInfo {
    repeated string name = 1;
}

// The device definition, sent from the client to the server
message PbDeviceDefinition {
    int32 id = 1;
    int32 unit = 2;
    PbDeviceType type = 3;
    // Device specific named parameters, e.g. the name of an image file
    map<string, string> params = 4;
    // The optional block size in bytes per sector, must be one of the supported block sizes
    int32 block_size = 5;
    // The device name components
    string vendor = 6;
    string product = 7;
    string revision = 8;
    // Create a write-protected device
    bool protected = 9;
}

// The device data, sent from the server to the client
message PbDevice {
    int32 id = 1;
    int32 unit = 2;
    PbDeviceType type = 3;
    PbDeviceProperties properties = 4;
    PbDeviceStatus status = 5;
    // Image file information, if the device supports image files
    PbImageFile file = 6;
    // Effective parameters the device was created with
    map<string, string> params = 7;
    string vendor = 8;
    string product = 9;
    string revision = 10;
    // Block size in bytes
    int32 block_size = 11;
    // Number of blocks
    uint64 block_count = 12;
}

message PbDevicesInfo {
    repeated PbDevice devices = 1;
}

// The reserved device IDs
message PbReservedIdsInfo {
    repeated int32 ids = 1;
}

// Piscsi server version information
message PbVersionInfo {
    // The piscsi version
    int32 major_version = 1;
    int32 minor_version = 2;
    // < 0 for a development version, = 0 if there is no patch yet
    int32 patch_version = 3;
}

// Commands piscsi can execute and their parameters
message PbCommand {
    PbOperation operation = 1;
    // The non-empty list of devices for this command
    repeated PbDeviceDefinition devices = 2;
    // The named parameters for the operation, e.g. a filename, or a network interface list
    map<string, string> params = 3;
}

// The result of a command
message PbResult {
    // false means that an error occurred
    bool status = 1;
    // An optional error or information message, depending on the status. A string without trailing CR/LF.
    string msg = 2;
    // An optional error code. Only to be used in cases where textual information is not sufficient.
    PbErrorCode error_code = 14;
    // Optional additional result data
    oneof result {
        // The result of a SERVER_INFO command
        PbServerInfo server_info = 3;
        // The result of a VERSION_INFO command
        PbVersionInfo version_info = 4;
        // The result of a LOG_LEVEL_INFO command
        PbLogLevelInfo log_level_info = 5;
        // The result of a DEVICES_INFO, ATTACH or DETACH command
        PbDevicesInfo devices_info = 6;
        // The result of a DEVICE_TYPES_INFO command
        PbDeviceTypesInfo device_types_info = 7;
        // The result of a DEFAULT_IMAGE_FILES_INFO command
        PbImageFilesInfo image_files_info = 8;
        // The result of an IMAGE_FILE_INFO command
        PbImageFile image_file_info = 9;
        // The result of a NETWORK_INTERFACES_INFO command
        PbNetworkInterfacesInfo network_interfaces_info = 10;
        // The result of an MAPPING_INFO command
        PbMappingInfo mapping_info = 11;
        // The result of a RESERVED_IDS_INFO command
        PbReservedIdsInfo reserved_ids_info = 12;
        // The result of an OPERATION_INFO command
        PbOperationInfo operation_info = 13;
    }
}

// The piscsi server information. All data can also be requested with individual commands.
message PbServerInfo {
    // The piscsi server version data
    PbVersionInfo version_info = 1;
    // The available log levels and the current log level
    PbLogLevelInfo log_level_info = 2;
    // Supported device types and their properties
    PbDeviceTypesInfo device_types_info = 3;
    // The image files in the default folder
    PbImageFilesInfo image_files_info = 4;
    // The available (up) network interfaces
    PbNetworkInterfacesInfo network_interfaces_info = 5;
    // The extensions to device types mapping
    PbMappingInfo mapping_info = 6;
    // The reserved device IDs
    PbReservedIdsInfo reserved_ids_info = 7;
    // The attached devices
    PbDevicesInfo devices_info = 8;
    // The operation meta data
    PbOperationInfo operation_info = 9;
}