SPICE_VERSION_MAJOR = 2 SPICE_VERSION_MINOR = 2
Copyright © 2009 Red Hat, Inc.
Licensed under a Creative Commons Attribution-Share Alike 3.0
United States License (see
http://creativecommons.org/licenses/by-sa/3.0/us/legalcode)
Spice protocol defines a set of protocol messages for accessing, controlling, and receiving inputs from remote computing devices (e.g., keyboard, video, mouse) across networks, and sending output to them. A controlled device can reside on either side, client and/or server. In addition, the protocol defines a set of calls for supporting migration of a remote server from one network address to another. Encryption of transported data, with one exception, was kept out of the protocol for maximum flexibility in choosing an encryption method. Spice uses simple messaging and does not depend on any RPC standard or a specific transport layer.
Spice communication session is split into multiple communication channels (e.g., every channel is a remote device) in order to have the ability to control communication and execution of messages according to the channel type (e.g. QoS encryption), and to add and remove communication channels during run time (which is supported by spice protocol definition). The following communication channels are defined in the current protocol definition: a). the main channel serves as the main spice session connection b). display channel for receiving remote display updates c). inputs channel for sending mouse and keyboard events d). cursor channel for receiving pointer shape and position e). Playback channel for receiving audio stream, and f). Record channel for sending audio capture. More channel types will be added as the protocol evolves. Spice also defines a set of protocol definitions for synchronizing channels` execution on the remote site.
Endianness
Unless stated otherwise, all data structures are packed and byte and bit order is in little endian format.
Data types
UINT8 – 8 bits unsigned integer
INT16 – 16 bits signed integer
UINT16 – 16 bits unsigned integer
UINT32 – 32 bits unsigned integer
INT32 - 32 bits signed integer
UINT64 – 64 bits unsigned integer
SPICE_ADDRESS - 64 bits unsigned integer, value is the offset of the addressed data from the beginning of spice protocol message body (i.e., data following SpiceDataHeader or SpicedSubMessage).
SPICE_FIXED28_4 – 32 bits fixed point number. 28 high bits are signed integer. Low 4 bits is unsigned integer numerator of a fraction with denominator 16.
POINT
INT32 x
INT32 y
POINT16
INT16 x
INT16 y
RECT
INT32 top
INT32 left
INT32 bottom
INT32 right
POINTFIX
SPICE_FIXED28_4 x
SPICE_FIXED28_4 y
Protocol Magic number UINT8[4]
SPICE_MAGIC = { 0x52, 0x45, 0x44, 0x51} // "REDQ"
Protocol version
Protocol version defined as two UINT32 values, major protocol version and minor protocol version. Server and client having the same major version must keep compatibility regardless of minor version (i.e., incrementing the major version brakes compatibility). Major protocol version with "huge" value are reserved for development purposes and are considered unsupported and unreliable. "huge" values are defined as having bit 31 set. The minor protocol version is incremented on every protocol change that does not break compatibility. It is set to zero on major protocol version increment.
Current Protocol version
SPICE_VERSION_MAJOR = 2 SPICE_VERSION_MINOR = 2
Compatibility – UINT32[]
In order to allow some degree of flexibility in client and server implementation and in order to improve compatibility, spice protocol supports bidirectional exchange of channels compatibilities. Compatibilities are expressed in UINT32 vector that is split into two groups: common compatibilities and channels compatibilities. Common compatibilities stands for compatibilities shared by all channels, and channels compatibilities stands for channel specific compatibilities. Splitting the vector into two types allows us to add channel compatibilities independently. Each compatibility is expressed using one or more bits in the compatibilities vector. For example capability 0 will be the low bit of the first (index 0) UINT32.
Channel types – UINT8
SPICE_CHANNEL_MAIN = 1 SPICE_CHANNEL_DISPLAY = 2 SPICE_CHANNEL_INPUTS = 3 SPICE_CHANNEL_CURSOR = 4 SPICE_CHANNEL_PLAYBACK = 5 SPICE_CHANNEL_RECORD = 6 SPICE_CHANNEL_TUNNEL = 7 // obsolete SPICE_CHANNEL_SMARTCARD = 8 SPICE_CHANNEL_USBREDIR = 9 SPICE_CHANNEL_PORT = 10 SPICE_CHANNEL_WEBDAV = 11
Error codes UINT32
SPICE_LINK_ERR_OK = 0 SPICE_LINK_ERR_ERROR = 1 SPICE_LINK_ERR_INVALID_MAGIC = 2 SPICE_LINK_ERR_INVALID_DATA = 3 SPICE_LINK_ERR_VERSION_MISMATCH = 4 SPICE_LINK_ERR_NEED_SECURED = 5 SPICE_LINK_ERR_NEED_UNSECURED = 6 SPICE_LINK_ERR_PERMISSION_DENIED = 7 SPICE_LINK_ERR_BAD_CONNECTION_ID = 8 SPICE_LINK_ERR_CHANNEL_NOT_AVAILABLE = 9
Warning codes
SPICE_WARN_GENERAL = 0
Information codes
SPICE_INFO_GENERAL = 0
public key buffer size.
SPICE_TICKET_PUBKEY_BYTES = 162 /* size needed for holding 1024 bit RSA public key in X.509 SubjectPublicKeyInfo format. */
Channel link: establishing a channel connection.
Connection process
The channel connection process is initiated by the client. The client sends SpiceLinkMess. In response, the server sends SpiceLinkReply. When the client receives SpiceLinkReply, it examines the error code and in case there is no error it encrypts its password with public key received in SpiceLinkReply and sends it to the server. The server receive the password and sends the link result to the client. The client examines the link result, and in case the result equals to SPICE_LINK_ERR_OK, a valid connection is established.
Channel connection for channel types other then SPICE_CHANNEL_MAIN is allowed only after the client has active SPICE_CHANNEL_MAIN channel connection. Only one SPICE_CHANNEL_MAIN connection is allowed, and this channel connection establishes spice session with the remote server.
Ticketing
Ticketing is a mechanism implemented in spice to ensure connections are opened only from authorized sources. To enable this mechanism a ticket is set in spice server consisting of a password and time validity. After time validity passes, the whole ticket is expired. The ticket is encrypted. To encrypt, server generates a 1024 bit RSA key and send the public part to the client (via RedLinkInfo). Client uses this key to encrypt the password and send it back to server (after SpiceLinkMess). Server decrypt the password, compare it to ticket and ensure it was received within the allowed time-frame.
SpiceLinkMess definition.
UINT32 magic |
value of this fields must be equal to SPICE_MAGIC |
UINT32 major_version |
value of this fields must be equal to SPICE_VERSION_MAJOR |
UINT32 minor_version |
value of this fields must be equal to SPICE_VERSION_MINOR |
UINT32 size |
number of bytes following this field to the end of this message. |
UINT32 connection_id |
In case of a new session (i.e., channel type is SPICE_CHANNEL_MAIN) this field is set to zero, and in response the server will allocate session id and will send it via the SpiceLinkReply message. In case of all other channel types, this field will be equal to the allocated session id. |
UINT8 channel_type |
one of SPICE_CHANNEL_? |
UINT8 channel_id |
channel id to connect to. This enables having multiple channels of the same type. |
UINT32 num_common_caps |
number of common client channel capabilities words |
UINT32 num_channel_caps |
number of specific client channel capabilities words |
UINT32 caps_offset |
location of the start of the capabilities vector given by the bytes offset from the “ size” member (i.e., from the address of the “connection_id” member). |
SpiceLinkReply definition
UINT32 magic |
value of this field must be equal to SPICE_MAGIC |
UINT32 major_version |
server major protocol version. |
UINT32 minor_version |
server minor protocol version. |
UINT32 size |
number of bytes following this field to the end of this message. |
UINT32 error |
Error codes (i.e., SPICE_LINK_ERR_?) |
UINT8[SPICE_TICKET_PUBKEY_BYTES] pub_key |
1024 bit RSA public key in X.509 SubjectPublicKeyInfo format. |
UINT32 num_common_caps |
number of common server channel capabilities words |
UINT32 num_channel_caps |
number of specific server channel capabilities words |
UINT32 caps_offset |
location of the start of the capabilities vector given by the bytes offset from the “ size” member (i.e., from the address of the “connection_id” member) |
Encrypted Password
Client sends RSA encrypted password, with public key received from server (in SpiceLinkReply). Format is EME-OAEP as described in PKCS#1 v2.0 with SHA-1, MGF1 and an empty encoding parameter.
Link Result UINT32
The server sends link result error code (i.e., SPICE_LINK_ERR_?)
Protocol message definition
All messages transmitted after the link stage have a common message layout. It begins with SpiceDataHeader which describes one main message and an optional sub messages list.
SpiceDataHeader
UINT64 serial |
serial number of the message within the channel. Serial numbers start with a value of 1 and are incremented on every message transmitted. |
UINT16 type |
message type can be one that is accepted by all channel (e.g., SPICE_MSG_MIGRATE), or specific to a channel type (e.g., SPICE_MSG_DISPLAY_MODE for display channel). |
UINT32 size |
size of the message body in bytes. In case sub_list (see below) is not zero then the actual main message size is sub_list. The message body follows SpiceDataHeader |
UINT32 sub_list |
optional sub-messages list. If this field is not zero then sub_list is the offset in bytes to SpiceSubMessageList from the end of SpiceDataHeader. All sub-messages need to be executed before the main message, and in the order they appear in the sub-messageslist. |
SpiceSubMessageList
UINT16 size |
number of sub-messages in this list. |
UINT32[] sub_messages |
array of offsets to sub message, offset is number of bytes from the end of SpiceDataHeader to start of SpicedSubMessage. |
SpicedSubMessage
UINT16 type |
message type can be one that is accepted by all channel (e.g., SPICE_MSG_MIGRATE), or specific to a channel type (e.g., SPICE_MSG_DISPLAY_MODE for display channel). |
UINT32 size |
size of the message body in bytes. The message body follows SpicedSubMessage. |
Common messages and messaging naming convention
Messages types and message body structures are prefixed according to the source of the message. The prefixes for messages sent from the server to the client are SPICE_MSG for types and SpiceMsg for structures. For messages sent from the client the prefixes are SPICE_MSGC and SpiceMsgc.
Server messages that are common to all channels
SPICE_MSG_MIGRATE = 1 SPICE_MSG_MIGRATE_DATA = 2 SPICE_MSG_SET_ACK = 3 SPICE_MSG_PING = 4 SPICE_MSG_WAIT_FOR_CHANNELS = 5 SPICE_MSG_DISCONNECTING = 6 SPICE_MSG_NOTIFY = 7 SPICE_MSG_FIRST_AVAIL = 101
Specific channel server messages start from SPICE_MSG_FIRST_AVAIL. All message types from SPICE_MSG_NOTIFY + 1 to SPICE_MSG_FIRST_AVAIL – 1 are reserved for further use.
Client messages that are common to all channels
SPICE_MSGC_ACK_SYNC = 1 SPICE_MSGC_ACK = 2 SPICE_MSGC_PONG = 3 SPICE_MSGC_MIGRATE_FLUSH_MARK = 4 SPICE_MSGC_MIGRATE_DATA = 5 SPICE_MSGC_DISCONNECTING = 6 SPICE_MSGC_FIRST_AVAIL = 101
Specific channel client messages start from SPICE_MSGC_FIRST_AVAIL. All message types from SPICE_MSGC_ACK_SYNC+ 1 to SPICE_MSGC_FIRST_AVAIL – 1 are reserved for further use.
Messages acknowledgment.
Spice provides a set of messages for requesting an acknowledgment on every one or more messages that the client consumes. In order to request acknowledgment messages, the server sends SPICE_MSG_SET_ACK with the requested acknowledgment frequency – after how many received messages the client sends acknowledgment. . In response, the client sends SPICE_MSGC_ACK_SYNC. From this point, for every requested number of messages that the client receive, it will send a SPICE_MSGC_ACK message.
SPICE_MSG_SET_ACK, SpiceMsgSetAck
UINT32 generation |
the generation of the acknowledgment sequence. This value will be sent back by SPICE_MSGC_ACK_SYNC. It is used for acknowledgment accounting synchronization. |
UINT32 window |
the window size. Spice client will send acknowledgment for every “window” messages. Zero window size will disable messages acknowledgment. |
SPICE_MSGC_ACK_SYNC, UINT32
UINT32 |
Spice client sends SpiceMsgSetAck.generation in response to SPICE_MSG_SET_ACK |
SPICE_MSGC_ACK, VOID
Spice client sends SPICE_MSGC_ACK message for every SpiceMsgSetAck.window messages it consumes.
Ping
Spice protocol provides ping messages for debugging purpose. Spice server sends SPICE_MSG_PING and the client responses with SPICE_MSGC_PONG. The server can measure round trip time by subtracting current time with the time that is returned in SPICE_MSGC_PONG message.
SPICE_MSG_PING, SpiceMsgPing
UINT32 id |
the id of this message |
UINT64 time |
time stamp of this message |
SPICE_MSGC_PONG, SpiceMsgPing
UINT32 id |
Spice client copies it from SpiceMsgPing.id |
UINT64 time |
Spice client copies it from SpiceMsgPing.time |
Channel migration
Spice supports migration of Spice server. The following common messages combined with specific main channel messages is used for migrating channels connections between spice servers. We will refer these servers as source and destination. Main channel is used for initiating and controlling the migration process. The following describes the actual channel migration process.
Channel migration process starts with sending SPICE_MSG_MIGRATE message from the server. The client receives the message, examine the attached flags and: if the server requests messages flush (i.e., SPICE_MIGRATE_NEED_FLUSH flag is on), the client sends SPICE_MSGC_MIGRATE_FLUSH_MARK message to the server. This procedure can be used to ensure safe delivery of all mid air messages before performing the migration action. if the server requests data transfer (i.e., SPICE_MIGRATE_NEED_DATA_TRANSFER flag is on), the client expects to receive one last message from the server before migrating to destination. This message type must be SPICE_MSG_MIGRATE_DATA type. The content of the received message will be transmitted to the destination on connection swap.
Afterward, the client swaps communication channels (i.e., starts using the connection with the destination server). The client can close connection with the source server only after all other channels also have finished the migration process. If the server side has requested data transfer, the client first transmits SPICE_MSGC_MIGRATE_DATA message containing the data received on SPICE_MSG_MIGRATE_DATA.
Migration flags
SPICE_MIGRATE_NEED_FLUSH = 1 SPICE_MIGRATE_NEED_DATA_TRANSFER = 2
SPICE_MSG_MIGRATE, SpiceMsgMigrate
UINT32 flags |
combination of SPICE migration flags. |
SPICE_MSG_MIGRATE_DATA, UINT8[]
Server migrate data, body of this message is variable length raw data that is determined by each channel type independently
SPICE_MSGC_MIGRATE_FLUSH_MARK, VOID
This messages mark completion of client communication channel flushing.
SPICE_MSGC_MIGRATE_DATA, UINT8[]
Post migration data, sent by client to the destination, containing the data sent by the source using the SPICE_MSG_MIGRATE_DATA message.
Channel synchronization
Spice provides mechanism for synchronizing channels message execution on the client side. The server sends SPICE_MSG_WAIT_FOR_CHANNELS message which contains a list of channels messages to wait for (i.e., SpiceMsgWaitForChannels). The Spice client will wait for completion of all the messages that are in that list before executing any more messages.
SpiceWaitForChannel
UINT8 type |
channel type (e.g., SPICE_CHANNEL_INPUTS) |
UINT8 id |
channel id. |
UIN64 serial |
message serial id (i.e, SpiceDataHeader.serial) to wait for |
SPICE_MSG_WAIT_FOR_CHANNELS, SpiceMsgWaitForChannels
UINT8 wait_count |
number of items in wait_list |
SpiceWaitForChannel[] wait_list |
list of channels to wait for. |
Disconnect reason
The following messages are used for notification about orderly disconnection of the server or client.
SPICE_MSG_DISCONNECTING, SpiceMsgDisconnect
UINT64 time_stamp |
time stamp of disconnect action on the server. |
UINT32 reason |
disconnect reason, SPICE_LINK_ERR_? |
SPICE_MSGC_DISCONNECTING, SpiceMsgDisconnect
UINT64 time_stamp |
time stamp of disconnect action on the client. |
UINT32 reason |
disconnect reason, SPICE_LINK_ERR_? |
Server notification
Spice protocol defines message for delivering notifications to the client using SPICE_MSG_NOTIFY message. Messages are categorized by severity and visibility. The later can be used as hint for the way the message is displayed to the user. For example high visibility notifications will trigger message box and low visibility notifications will be directed to the log.
SPICE_MSG_NOTIFY, SpiceMsgNotify
UINT64 time_stamp |
server side time stamp of this message. |
UINT32 severity |
one of SPICE_NOTIFY_SEVERITY_? |
UINT32 visibility |
one of SPICE_NOTIFY_VISIBILITY_? |
UINT32 what |
one of SPICE_LINK_ERR_?, SPICE_WARN_? Or SPICE_INFO_?, depending on severity. |
UINT32 message_len |
size of message |
UINT8[] message |
message string in UTF8. |
UINT8 0 |
string zero termination |
Server messages
SPICE_MSG_MAIN_MIGRATE_BEGIN = 101 SPICE_MSG_MAIN_MIGRATE_CANCEL = 102 SPICE_MSG_MAIN_INIT = 103 SPICE_MSG_MAIN_CHANNELS_LIST = 104 SPICE_MSG_MAIN_MOUSE_MODE = 105 SPICE_MSG_MAIN_MULTI_MEDIA_TIME = 106 SPICE_MSG_MAIN_AGENT_CONNECTED = 107 SPICE_MSG_MAIN_AGENT_DISCONNECTED = 108 SPICE_MSG_MAIN_AGENT_DATA = 109 SPICE_MSG_MAIN_AGENT_TOKEN = 110
Client messages
SPICE_MSGC_MAIN_CLIENT_INFO = 101 SPICE_MSGC_MAIN_MIGRATE_CONNECTED = 102 SPICE_MSGC_MAIN_MIGRATE_CONNECT_ERROR = 103 SPICE_MSGC_MAIN_ATTACH_CHANNELS = 104 SPICE_MSGC_MAIN_MOUSE_MODE_REQUEST = 105 SPICE_MSGC_MAIN_AGENT_START = 106 SPICE_MSGC_MAIN_AGENT_DATA = 107 SPICE_MSGC_MAIN_AGENT_TOKEN = 108
Migration control
Spice migration control is performed using the main channel messages. Spice server initiates migration process by sending SPICE_MSG_MAIN_MIGRATE_BEGIN message. Once the client has completed its pre-migrate procedure it notifies the server by transmitting SPICE_MSGC_MAIN_MIGRATE_CONNECTED message. In case of pre-migrate procedure error, the client sends SPICE_MSGC_MAIN_MIGRATE_CONNECT_ERROR. Once the server receives SPICE_MSGC_MAIN_MIGRATE_CONNECTED he can commence the migration process. The server can send SPICE_MSG_MAIN_MIGRATE_CANCEL in order to instruct the client to cancel the migration process.
SPICE_MSG_MAIN_MIGRATE_BEGIN, SpiceMsgMainMigrationBegin
UINT16 port |
port of destination server |
UINT16 sport |
secure port of destination server |
UINT8[] host_name |
host name of destination server |
SPICE_MSG_MAIN_MIGRATE_CANCEL, VOID
Instruct the client to cancel migration process
SPICE_MSGC_MAIN_MIGRATE_CONNECTED, VOID
Notify the server of successful completion of the pre-migrate stage
SPICE_MSGC_MAIN_MIGRATE_CONNECT_ERROR, VOID
Notify the server of pre-migrate stage error
Mouse modes
Spice protocol specifies two mouse modes, client mode and server mode. In client mode, the affective mouse is the client side mouse: the client sends mouse position within the display and the server sends mouse shape messages. In server mode, the client sends relative mouse movements and the server sends position and shape commands. Spice main channel is used for mouse mode control.
Modes
SPICE_MOUSE_MODE_SERVER = 1 SPICE_MOUSE_MODE_CLIENT = 2
SPICE_MSG_MAIN_MOUSE_MODE, SpiceMsgMainMouseMode
Spice server sends this message on every mouse mode change
UINT32 supported_modes |
current supported mouse mode, this is any combination of SPICE_MOUSE_MODE_? |
UINT32 current_mode |
the current mouse mode. Can be one of SPICE_MOUSE_MODE_? |
SPICE_MSGC_MAIN_MOUSE_MODE_REQUEST, UINT32
Spice client sends this message to request specific mouse mode. It is not guarantied that the server will accept the request. Only on receiving SPICE_MSG_MAIN_MOUSE_MODE message, the client can know of actual mouse mode change.
UINT32 |
requested mode, one of SPICE_MOUSE_MODE_? |
Main channel init message
Spice server must send SpiceMsgMainInit as the first transmitted message t and is disallowed to send it at any other point.
SPICE_MSG_MAIN_INIT, SpiceMsgMainInit
UINT32 session_id |
session id is generated by the server. This id will be send on every new channel connection within this session (i.e., in SpiceLinkMess.connection_id). |
UINT32 display_channels_hint |
optional hint of expected number of display channels. Zero is defined as an invalid value |
UINT32 supported_mouse_modes |
supported mouse modes. This is any combination of SPICE_MOUSE_MODE_? |
UINT32 current_mouse_mode |
the current mouse mode, one of SPICE_MOUSE_MODE_? |
UINT32 agent_connected |
current state of Spice agent (see This Section), 0 and 1 stand for disconnected and connected state respectively. |
UINT32 agent_tokens |
number of available tokens for sending messages to Spice agent. |
UINT32 multi_media_time |
current server multimedia time. The multimedia time is used for synchronizing video (for more information see Multimedia time) |
UINT32 ram_hint |
optional hint for help in determining global LZ compression dictionary size (for more information see section Spice Image in “Display Channel”). |
Server side channels notification
In order to have the ability to dynamically attach to the server side channels, Spice protocol includes SPICE_MSG_MAIN_CHANNELS_LIST message. This massage informs the client of available channels in the server side. In response to this message the client can decide to link with the new available channel(s). The server must receive SPICE_MSGC_MAIN_ATTACH_CHANNELS before sending any SPICE_MSG_MAIN_CHANNELS_LIST message.
SPICE_MSG_MAIN_CHANNELS_LIST, SpiceMsgChannels
UINT32 num_of_channels |
number of channels in this list |
SpiceChannelId[] channels |
vector of “num_of_channels” channel ids |
SpiceChannelId
UINT8 type |
channel type, one of SPICE_CHANNEL_? channel types, except for SPICE_CHANNEL_MAIN |
UINT8 id |
channel id |
Multimedia time
Spice defines messages for setting multimedia time for synchronization of video and audio streams. Two methods for updating multimedia time are supported. The first method uses the time stamp of data that arrives on the playback channel.The second method uses the main channel SPICE_MSG_MAIN_MULTI_MEDIA_TIME message. The latter method is used when no active playback channel exist.
SPICE_MSG_MAIN_MULTI_MEDIA_TIME, UINT32
UINT32 |
multimedia time |
Spice agent
Spice protocol defines a set of messages for bidirectional communication channel between Spice client and spice client agent on the remote server. Spice provides a communication channel only, the actual transferred data content is opaque to the protocol. This channel can be used for various purposes, for example, client-guest clipboard sharing, authentication and display configuration.
Spice client receives notifications of remote site agent connection as part of the SPICE_MSG_MAIN_INIT message or by a specific server SPICE_MSG_MAIN_AGENT_CONNECTED. Remote agent disconnection notification is delivered by SPICE_MSG_MAIN_AGENT_DISCONNECTED message. A bidirectional tokens mechanism is used in order to prevent blocking of the main channel with agent messages (e.g., in case the agent stops consuming the data). Each side is not allowed to send more messages than the tokens allocated to it by the other side. The number of tokens that are allocated for the client is initialized from SPICE_MSG_MAIN_INIT message, and farther allocation of tokens is done using SPICE_MSG_MAIN_AGENT_TOKEN. Server tokens initial count is delivered in SPICE_MSGC_MAIN_AGENT_START message. This message must be the first agent related message that the client sends to the server. Farther tokens allocation for the server is done using SPICE_MSGC_MAIN_AGENT_TOKEN. Actual data packets are delivered using SPICE_MSG_MAIN_AGENT_DATA and SPICE_MSGC_MAIN_AGENT_DATA.
Although agent messages are opaque for the protocol, agent data stream is defined by Spice protocol in order to delineate messages. Still, the client-server communication is independent from the agent channel, e.g., agent protocol conflicts don’t affect the rest of the channels. Agent stream is defined as a run of messages having the following format:
UINT32 protocol |
unique protocol of this message. The protocol id must be registered in order to prevent conflicts. |
UINT32 type |
protocol dependent message type. |
UINT64 opaque |
protocol dependent opaque data. |
UINT32 size |
size of data in bytes. |
UINT8 data[0] |
data of this message. |
Client and server must continue processing unknown protocols messages or messages having unknown type (i.e., receive and dump).
SPICE_MSG_MAIN_AGENT_CONNECTED, VOID
SPICE_MSG_MAIN_AGENT_DISCONNECTED, UINT32
UINT32 |
disconnect error code SPICE_LINK_ERR_? |
SPICE_AGENT_MAX_DATA_SIZE = 2048
SPICE_MSG_MAIN_AGENT_DATA, UINT8[]
Agent packet is the entire message body (i.e. SpiceDataHeader.size). The maximum packet size is SPICE_AGENT_MAX_DATA_SIZE.
SPICE_MSG_MAIN_AGENT_TOKEN, UINT32
UINT32 |
allocated tokens count for the client |
SPICE_MSGC_MAIN_AGENT_START, UINT32
UINT32 |
allocated tokens count for the server |
SPICE_MSGC_MAIN_AGENT_DATA, UINT8[]
Agent packet is the entire message body (i.e. SpiceDataHeader.size). The maximum packet size is SPICE_AGENT_MAX_DATA_SIZE.
SPICE_MSGC_MAIN_AGENT_TOKEN, UINT32
UINT32 |
allocated tokens count for the server |
Spice Inputs channel controls the server mouse and the keyboard.
Client messages
SPICE_MSGC_INPUTS_KEY_DOWN = 101 SPICE_MSGC_INPUTS_KEY_UP = 102 SPICE_MSGC_INPUTS_KEY_MODIFIERS = 103 SPICE_MSGC_INPUTS_MOUSE_MOTION = 111 SPICE_MSGC_INPUTS_MOUSE_POSITION = 112 SPICE_MSGC_INPUTS_MOUSE_PRESS = 113 SPICE_MSGC_INPUTS_MOUSE_RELEASE = 114
Server Messages
SPICE_MSG_INPUTS_INIT = 101 SPICE_MSG_INPUTS_KEY_MODIFIERS = 102 SPICE_MSG_INPUTS_MOUSE_MOTION_ACK = 111
Keyboard messages
Spice supports sending keyboard key events and keyboard leds synchronization. The client sends key event using SPICE_MSGC_INPUTS_KEY_DOWN and SPICE_MSGC_INPUTS_KEY_UP messages. Key value is expressed using PC AT scan code (see KeyCode). Keyboard leds synchronization is done by sending SPICE_MSG_INPUTS_KEY_MODIFIERS message by the server or by sending SPICE_MSGC_INPUTS_KEY_MODIFIERS by the client, these messages contain keyboard leds state. Keyboard modifiers is also sent by the server using SPICE_MSG_INPUTS_INIT, this message must be sent as the first server message and the server mustn’t send it at any other point.
Keyboard led bits
SPICE_SCROLL_LOCK_MODIFIER = 1 SPICE_NUM_LOCK_MODIFIER = 2 SPICE_CAPS_LOCK_MODIFIER = 4
SPICE_MSG_INPUTS_INIT, UINT32
UINT32 |
any combination of keyboard led bits. If bit is set then the led is on. |
SPICE_MSG_INPUTS_KEY_MODIFIERS, UINT32
UINT32 |
any combination of keyboard led bits. If bit is set then the led is on. |
SPICE_MSGC_INPUTS_KEY_MODIFIERS, UINT32
UINT32 |
any combination of keyboard led bits. If bit is set then the led is on. |
KeyCode
UINT8[4] |
the value of key code is a PC AT scan code. The code is composed by up to four bytes for supporting extended codes. A code is terminated by a zero byte. |
SPICE_MSGC_INPUTS_KEY_DOWN, KeyCode
KeyCode |
client sends this message to notify of key press event. |
SPICE_MSGC_INPUTS_KEY_UP, KeyCode
KeyCode – client sends this message to notify of key release event.
Mouse messages
spice support two modes of mouse operation: client mouse and server mouse (for more information see mouse modes). in server mouse mode the client sends mouse motion message (i.e., msgc_inputs_mouse_motion), and in client mouse mode it sends position message (i.e., msgc_inputs_mouse_position). position message holds the position of the client mouse on the display and the id of the display channel, which is derived from SpiceLinkMess.channel_id. in order to prevent flood of mouse motion/position events, the server sends red_inputs_mouse_motion_ack message on every red_motion_ack_bunch messages it receive. this mechanism allows the client to keep track on the server’s messages consumption rate and to change the event pushing policy according to it. mouse button events are sent to the server using msgc_inputs_mouse_press and msgc_inputs_mouse_release messages.
Spice Button ID
SPICE_MOUSE_BUTTON_LEFT = 1, left button SPICE_MOUSE_BUTTON_MIDDLE = 2, middle button SPICE_MOUSE_BUTTON_RIGHT = 3, right button SPICE_MOUSE_BUTTON_UP = 4, scroll up button SPICE_MOUSE_BUTTON_DOWN = 5, scroll down button
Buttons masks
SPICE_MOUSE_BUTTON_MASK_LEFT = 1, left button mask SPICE_MOUSE_BUTTON_MASK_MIDDLE = 2, middle button mask SPICE_MOUSE_BUTTON_MASK_RIGHT = 4, right button mask
SPICE_INPUT_MOTION_ACK_BUNCH
SPICE_INPUT_MOTION_ACK_BUNCH = 4
SPICE_MSGC_INPUTS_MOUSE_MOTION, SpiceMsgcMouseMotion
INT32 dx |
number of pixels the mouse had moved on x axis |
INT32 dy |
number of pixels the mouse had moved on y axis |
UINT32 buttons_state |
any combination of buttons mask. Set bit describe pressed button and clear bit describe unpressed button. |
SPICE_MSGC_INPUTS_MOUSE_POSITION, SpiceMsgcMousePosition
UINT32 x |
position on x axis |
UINT32 y |
position on y axis |
UINT32 buttons_state |
any combination of buttons mask. Set bit describe pressed button and clear bit describe unpressed button. |
UINT8 display_id |
id of the display that client mouse is on. |
SPICE_MSGC_INPUTS_MOUSE_PRESS, SpiceMsgcMousePress
UINT32 button |
one of SPICE_MOUSE_?BUTTON |
UINT32 buttons_state |
any combination of buttons masks. Set bit describes pressed button, and clear bit describes unpressed button. |
SPICE_MSGC_INPUTS_MOUSE_RELEASE, SpiceMsgcMouseRelease
UINT32 button |
one of SPICE_MOUSE_?BUTTON |
UINT32 buttons_state |
any combination of buttons mask. Set bit describes pressed button and clear bit describes unpressed button. |
Spice protocol defines a set of messages for supporting rendering of the remote display area on the client display. The protocol supports rendering of graphics primitives (e.g., lines, images) and video streams. The protocol also supports caching of images and color palettes on the client side. Spice display channel supports several images compression methods for reducing network traffic.
Server messages
SPICE_MSG_DISPLAY_MODE = 101 SPICE_MSG_DISPLAY_MARK = 102 SPICE_MSG_DISPLAY_RESET = 103 SPICE_MSG_DISPLAY_COPY_BITS = 104 SPICE_MSG_DISPLAY_INVAL_LIST = 105 SPICE_MSG_DISPLAY_INVAL_ALL_PIXMAPS = 106 SPICE_MSG_DISPLAY_INVAL_PALETTE = 107 SPICE_MSG_DISPLAY_INVAL_ALL_PALETTES = 108 SPICE_MSG_DISPLAY_STREAM_CREATE = 122 SPICE_MSG_DISPLAY_STREAM_DATA = 123 SPICE_MSG_DISPLAY_STREAM_CLIP = 124 SPICE_MSG_DISPLAY_STREAM_DESTROY = 125 SPICE_MSG_DISPLAY_STREAM_DESTROY_ALL = 126 SPICE_MSG_DISPLAY_DRAW_FILL = 302 SPICE_MSG_DISPLAY_DRAW_OPAQUE = 303 SPICE_MSG_DISPLAY_DRAW_COPY = 304 SPICE_MSG_DISPLAY_DRAW_BLEND = 305 SPICE_MSG_DISPLAY_DRAW_BLACKNESS = 306 SPICE_MSG_DISPLAY_DRAW_WHITENESS = 307 SPICE_MSG_DISPLAY_DRAW_INVERS = 308 SPICE_MSG_DISPLAY_DRAW_ROP3 = 309 SPICE_MSG_DISPLAY_DRAW_STROKE = 310 SPICE_MSG_DISPLAY_DRAW_TEXT = 311 SPICE_MSG_DISPLAY_DRAW_TRANSPARENT = 312 SPICE_MSG_DISPLAY_DRAW_ALPHA_BLEND = 313
Client messages
SPICE_MSGC_DISPLAY_INIT = 101
Operation flow
Spice server sends to the client a mode message using SPICE_MSG_DISPLAY_MODE for specifying the current draw area size and format. In response the client creates a draw area for rendering all the followed rendering commands sent by the server. The client will expose the new remote display area content (i.e., after mode command) only after it receives a mark command (i.e., SPICE_MSG_DISPLAY_MARK) from the server. The server can send a reset command using SPICE_MSG_DISPLAY_RESET to instruct the client to drop its draw area and palette cache. Sending mode message is allowed only while no active draw area exists on the client side. Sending reset message is allowed only while active draw area exists on client side. Sending mark message is allowed only once, between mode and reset messages. Draw commands, copy bits command and stream commands are allowed only if the client have an active display area (i.e., between SPICE_MSG_DISPLAY_MODE to SPICE_MSG_DISPLAY_RESET).
On channel connection, the client optionally sends an init message, using SPICE_MSGC_DISPLAY_INIT, in order to enable image caching and global dictionary compression. The message includes the cache id and its size and the size of the dictionary compression window. These sizes and id are determined by the client. It is disallowed to send more then one init message.
Color pallets cache are manged by the server. Items cache insertion commands are sent as part of the rendering commands. Cache items removal are sent explicitly using SPICE_MSG_DISPLAY_INVAL_LIST or SPICE_MSG_DISPLAY_INVAL_LIST server messages. Resetting client caches is done by sending SPICE_MSG_DISPLAY_INVAL_ALL_PIXMAPS or SPICE_MSG_DISPLAY_INVAL_ALL_PALETTES server messages.
Draw area control
SPICE_MSG_DISPLAY_MODE, SpiceMsgDisplayMode
UINT32 width |
width of the display area |
UINT32 height |
height of the display area |
UINT32 depth |
color depth of the display area. Valid values are 16bpp or 32bpp. |
SPICE_MSG_DISPLAY_MARK, VOID
Mark the beginning of the display area visibility
SPICE_MSG_DISPLAY_RESET, VOID
Drop current display area of the channel and reset palette cache
Raster operation descriptor
The following defines a set of flags for describing raster operations that can be applied on a source image, source brush, destination and the result during a rendering operation. Combination of those flags defines the necessary steps that are needed to be preformed during a rendering operation. In the following definitions of rendering commands this combination is referred to by rop_descriptor.
SPICE_ROPD_INVERS_SRC = 1
Source Image need to be inverted before rendering
SPICE_ROPD_INVERS_BRUSH = 2
SpiceBrush need to be inverted before rendering
SPICE_ROPD_INVERS_DEST = 4
Destination area need to be inverted before rendering
SPICE_ROPD_OP_PUT = 8
SpiceCopy operation should be used.
SPICE_ROPD_OP_OR = 16
OR operation should be used.
SPICE_ROPD_OP_AND = 32
AND operation should be used.
SPICE_ROPD_OP_XOR = 64
XOR operation should be used.
SPICE_ROPD_OP_BLACKNESS = 128
Destination pixel should be replaced by black
SPICE_ROPD_OP_WHITENESS = 256
Destination pixel should be replaced by white
SPICE_ROPD_OP_INVERS = 512
Destination pixel should be inverted
SPICE_ROPD_INVERS_RES = 1024
Result of the operation needs to be inverted
OP_PUT, OP_OR, OP_AND, OP_XOR, OP_BLACKNESS, OP_WHITENESS, and OP_INVERS are mutually exclusive
OP_BLACKNESS, OP_WHITENESS, and OP_INVERS are exclusive
Raw raster image
The following section describes Spice raw raster image (Pixmap). Pixmap is one of several ways to transfer images in Spice protocol (for more information see Spice Image).
Pixmap format types
PIXMAP_FORMAT_1BIT_LE = 1
1 bit per pixel and bits order is little endian. Each pixel value is an index in a color table. The color table size is 2.
PIXMAP_FORMAT_1BIT_BE = 2
1 bit per pixel and bits order is big endian. Each pixel value is index in a color table. The color table size is 2.
PIXMAP_FORMAT_4BIT_LE = 3
4 bits per pixel and nibble order inside a byte is little endian. Each pixel value is an index in a color table. The color table size is 16.
PIXMAP_FORMAT_4BIT_BE = 4
4 bits per pixel and nibble order inside a byte is big endian. Each pixel value is an index in a color table. The color table size is 16.
PIXMAP_FORMAT_8BIT = 5
8 bits per pixel. Each pixel value is an index in a color table. The color table size is 256.
PIXMAP_FORMAT_16BIT = 6
pixel format is 16 bits RGB555.
PIXMAP_FORMAT_24BIT = 7
pixel format is 24 bits RGB888.
PIXMAP_FORMAT_32BIT = 8
pixel format is 32 bits RGB888.
PIXMAP_FORMAT_RGBA = 9
pixel format is 32 bits ARGB8888.
SpicePalette
UINT64 id |
unique id of the palette |
UINT16 table_size |
number of entries in the color table |
UINT32[] color_table |
each entry is RGB555 or RGB888 color depending on the current display area mode. If display area mode color depth is 32, the effective format is RGB888. If display area mode color depth is 16 the effective format is RGB555. |
Pixmap flags
PIXMAP_FLAG_PAL_CACHE_ME = 1
Instruct the client to add the palette to cache
PIXMAP_FLAG_PAL_FROM_CACHE = 2
Instruct the client to retrieve palette from cache.
PIXMAP_FLAG_TOP_DOWN = 4
Pixmap lines are ordered from top to bottom (i.e., line 0 is the highest line).
Pixmap
UINT8 format |
one of PIXMAP_FORMAT_? |
UINT8 flags |
combination of PIXMAP_FLAG_? |
UINT32 width |
width of the pixmap |
UINT32 height |
height of the pixmap |
UINT32 stride |
number of bytes to add for moving from the beginning of line n to the beginning of line n+1 |
union { SPICE_ADDRESS palette; UINT64 palette_id; } |
address of the color palette (must be zero if no color table is required for format) or id of the palette (valid if FLAG_PAL_FROM_CACHE is set). |
SPICE_ADDRESS data |
address of line 0 of the pixmap. |
LZ with palette
This section describes a data structure that is combination of a color palette and a compressed pixmap data. The pixmap is compressed using our implementation of LZSS algorithm (see next section). Each decoded pixel value is an index in the color palette.
LZPalette Flags
LZPALETTE_FLAG_PAL_CACHE_ME = 1
Instruct the client to add the palette to the cache
LZPALETTE_FLAG_PAL_FROM_CACHE = 2
Instruct the client to retrieve palette from the cache.
LZPALETTE_FLAG_TOP_DOWN = 4
pixmap lines are ordered from top to bottom (i.e. line 0 is the highest line).
LZPalette
UINT8 flags |
combination of LZPALETTE_FLAG_? |
UINT32 data_size |
size of compressed data |
union { SPICE_ADDRESS palette; UINT64 palette_id; } |
address of the color palette (see SpicePalette section in “Raw raster image”)[zero value is disallowed] or id of the palette (valid if FLAG_PAL_FROM_CACHE). |
UINT8[] data |
compressed pixmap |
Spice Image
The following section describes Spice image. Spice image is used in various commands and data structures for representing a raster image. Spice image supports several compression types in addition to the raw mode: Quic, LZ and GLZ. Quic is a predictive coding algorithm. It is a generalization of SFALIC from gray-scale to color images withe addition of RLE encoding. By LZ we refer to the our implementation of the LZSS algorithm, which was adjusted for images in different formats. By GLZ we refer to an extension of LZ that allows it to use a dictionary that is based on a set of images and not just on the image being compressed.
Image types
IMAGE_TYPE_PIXMAP = 0 SPICE_IMAGE_TYPE_QUIC = 1 SPICE_IMAGE_TYPE_LZ_PLT = 100 SPICE_IMAGE_TYPE_LZ_RGB = 101 SPICE_IMAGE_TYPE_GLZ_RGB = 102 SPICE_IMAGE_TYPE_FROM_CACHE = 103
Image flags
IMAGE_FLAG_CACHE_ME = 1, this flag instruct the client to add the image to image cache, cache key is SpiceImageDescriptor.id (see below).
SpiceImageDescriptor
UINT64 id |
unique id of the image |
UINT8 type |
type of the image. One of IMAGE_TYPE_? |
UINT8 flags |
any combination of IMAGE_FLAG_? |
UINT32 width |
width of the image |
UINT32 height |
height of the image |
Image data
Image data follows SpiceImageDescriptor and its content depends on SpiceImageDescriptor.type:
In case of PIXMAP – content is Pixmap.
In case of QUIC – content is Quic compressed image. Data begins with the size of the compressed data, represented by UINT32, followed by the compressed data.
In case of LZ_PLT – content is LZPalette.
In case of LZ_RGB – content is LZ_RGB – LZ encoding of an RGB image. Data begins with the size of the compressed data, represented by UINT32, followed by the compressed data.
In case of GLZ_RGB – content is GLZ_RGB – GLZ encoding of an RGB image. Data begins with the size of the compressed data, represented by UINT32, , followed by the compressed data.
In case of FROM_CACHE – No image data. The client should use SpiceImageDescriptor.id to retrieve the relevant image from cache.
Glyph SpiceString
Glyph string defines an array of glyphs for rendering. Glyphs in a string can be in A1, A4 or A8 format (i.e., 1bpp, 4bpp, or 8bpp alpha mask). Every glyph contains its rendering position on the destination draw area.
SpiceRasterGlyph
POINT render_pos |
location of the glyph on the draw area |
POINT glyph_origin |
origin of the glyph. The origin is relative to the upper left corner of the draw area. Positive value on x axis advances leftward and positive value on y axis advances upward. |
UINT16 width |
glyph’s width |
UINT16 height |
glyph’s height |
UINT8[] data |
alpha mask of the glyph. Actual mask data depends on the glyph string’s flags. If the format is A1 then the line stride is ALIGN(width, 8) / 8. If the format is A4, the line stride is ALIGN(width, 2) / 2. If the format is A8, the line stride is width. |
Glyph SpiceString flags
GLYPH_STRING_FLAG_RASTER_A1 = 1
Glyphs type is 1bpp alpha value (i.e., 0 is transparent 1 is opaque)
GLYPH_STRING_FLAG_RASTER_A4 = 2
Glyphs type is 4bpp alpha value (i.e., 0 is transparent 16 is opaque)
GLYPH_STRING_FLAG_RASTER_A8 = 4
Glyphs type is 4bpp alpha value (i.e., 0 is transparent 256 is opaque)
GLYPH_STRING_FLAG_RASTER_TOP_DOWN = 8
Line 0 is the top line of the mask
GlyphString
UINT16 length |
number of glyphs |
UINT16 flags |
combination of GLYPH_STRING_FLAG_? |
UINT8[] data |
glyphs |
Data Types
RectList
UINT32 count |
number of RECT items in rects |
RECT[] rects |
array of <count> RECT |
Path segment flags
PATH_SEGMENT_FLAG_BEGIN = 1
this segment begins a new path
PATH_SEGMENT_FLAG_END = 2
this segment ends the current path
PATH_SEGMENT_FLAG_CLOSE = 8
this segment closes the path and is invalid if PATH_SEGMENT_FLAG_END is not set
PATH_SEGMENT_FLAG_BEZIER = 16
this segment content is a Bezier curve
SpicePathSeg
UINT32 flags |
any combination of PATH_SEGMENT_FLAG_? |
UINT32 count |
number of points in the segment |
POINTFIX[] points |
segment points |
PathSegList
List of SpicePathSeg items. End of the list is reached if the sum of all previous PathSegs' sizes is equal to list_size. Address of next segment is the address of SpicePathSeg.points[SpicePathSeg.count]
UINT32 list_size |
total size of in bytes of all PathSegs in the list, |
SpicePathSeg seg0 – first path segment.
SpiceClip types
SPICE_CLIP_TYPE_NONE = 0
no clipping
SPICE_CLIP_TYPE_RECTS = 1
data is RectList and union of all rectangles in RectList is the effective clip
SPICE_CLIP_TYPE_PATH = 2
data is PathSegList and the figure described by PathSegList is the effective clip
SpiceClip
UIN32 type |
one of CLIP_TYPE_? |
SPICE_ADDRESS data |
address of clip data. The content depends on <type> |
Mask flags
MASK_FLAG_INVERS = 1, the effective mask is the inverse of the mask
Mask
UINT8 flags |
flags of the mask, combination of MASK_FLAG_? |
POINT position |
origin of the mask in bitmap coordinates |
SPICE_ADDRESS bitmap |
address of the mask’s image, the format of the image must be 1bpp. If the bitmap is zero then no masking operation needs to be preformed. |
In all rendering commands, the mask must be big enough to cover the destination rectangle
SpiceBrush types
SPICE_BRUSH_TYPE_NONE = 0 /* the brush is invalid */ SPICE_BRUSH_TYPE_SOLID = 1 /* the brush is solid RGB color */ SPICE_BRUSH_TYPE_PATTERN = 2 /* the brush is a pattern */
SpicePattern
SPICE_ADDRESS image |
address of the pattern’s Image |
POINT position |
origin coordinates of the pattern in the image |
SpiceBrush
UINT32 type |
one of BRUSH_TYPE_? |
Union { UINT32 color; */ RGB color. The format of the color depends on current draw area mode.*/ SpicePattern pattern; }
Image scale mode
The following defines the method for scaling image
SPICE_IMAGE_SCALE_MODE_INTERPOLATE = 0
The client is allowed to INTERPOLATE pixel color.
SPICE_IMAGE_SCALE_MODE_NEAREST = 1
The client must use the nearest pixel.
LineAtrr flags
LINE_ATTR_FLAG_START_WITH_GAP = 4
first style segment if gap (i.e., foreground)
LINE_ATTR_FLAG_STYLED = 8
style member of LineAtrr is valid and contains effective line style for the rendering operation.
LineAtrr join style
LINE_ATTR_JOIN_ROUND = 0 LINE_ATTR_JOIN_BEVEL = 1 LINE_ATTR_JOIN_MITER = 2
LineAtrr cap style
LINE_ATTR_CAP_ROUND = 0 LINE_ATTR_CAP_SQUARE = 1 LINE_ATTR_CAP_BUTT = 2
SpiceLineAttr
UINT8 flags |
combination of LINE_ATTR_? |
UINT8 join_style |
one of LINE_ATTR_JOIN_? |
UINT8 cap_style |
one of LINE_ATTR_CAP_? |
UINT8 style_num_segments |
number of style segments in line style |
SPICE_FIXED28_4 width |
width of the line in pixels |
SPICE_FIXED28_4 miter_limit |
miter limit in pixels |
SPICE_ADDRESS style |
address of line style line style is array of SPICE_FIXED28_4. The array defines segments that each represents length of foreground or background pixels in the style. If FLAG_START_WITH_GAP is defined then the first segment in the style is background, otherwise it is foreground. Renderer uses this array of segments repeatedly during rendering operation. |
Rendering command
SpiceMsgDisplayBase
Common field to all rendering command
RECT bounding_box |
the affected area on the display area |
SpiceClip clip |
the effective clip to set before rendering a command |
SPICE_MSG_DISPLAY_COPY_BITS
SpiceMsgDisplayBase
POINT source_positionSpiceCopy bits from the draw area to bounding_box on the draw area. Source area left top corner is source_position and its height and width is equal to bounding_box height and width. Source and destination rectangles can overlap.
SPICE_MSG_DISPLAY_DRAW_FILL
SpiceMsgDisplayBase
SpiceBrush brush
UINT16 rop_descriptor
Mask maskSpiceFill bounding_box using brush as the fill pattern and rop_descriptor instructions. If the mask is valid, it will limit the modified area (i.e., only pixels on the destination area that their corresponding bits are set will be affected).
SPICE_MSG_DISPLAY_DRAW_OPAQUE
SpiceMsgDisplayBase SPICE_ADDRESS source_image RECT source_area SpiceBrush brush UINT16 rop_descriptor UINT8 scale_mode Mask mask
Combine pixels from source_area in source_image with the brush’s pattern using rop_descriptor instructions. The result image will be rendered into bounding_box. In case scaling of source image is required it will be performed according to scale_mode and before the combination with brush pixels. If mask is valid it will limit the modified area.
SPICE_MSG_DISPLAY_DRAW_COPY
SpiceMsgDisplayBase SPICE_ADDRESS source_image RECT source_area UINT16 rop_descriptor UINT8 scale_mode Mask mask
SpiceCopy pixels from source_area in source_image to bounding_box using rop_descriptor instructions. In case scaling of source image is required it will be performed according to scale_mode and before the copying to the draw area. If mask is valid it will limit the modified area.
SPICE_MSG_DISPLAY_DRAW_BLEND
SpiceMsgDisplayBase SPICE_ADDRESS source_image RECT source_area UINT16 rop_descriptor UINT8 scale_mode Mask mask
Mixing pixels from source_area in source_image with bounding_box pixels on the draw area using rop_descriptor instructions. In case scaling of source image is required it will be performed according to scale_mode and before the mixing with the draw area. If mask is valid it will limit the modified area.
SPICE_MSG_DISPLAY_DRAW_BLACKNESS
SpiceMsgDisplayBase Mask mask
SpiceFill bounding_box with black pixels. If mask is valid it will limit the modified area.
SPICE_MSG_DISPLAY_DRAW_WHITENESS
SpiceMsgDisplayBase Mask mask
SpiceFill bounding_box with white pixels. If mask is valid it will limit the modified area.
SPICE_MSG_DISPLAY_DRAW_INVERS
SpiceMsgDisplayBase Mask mask
Inverse all pixels in bounding_box. If mask is valid it will limit the modified area.
SPICE_MSG_DISPLAY_DRAW_ROP3
SpiceMsgDisplayBase SPICE_ADDRESS source_image RECT source_area SpiceBrush brush UINT8 rop3 UINT8 scale_mode Mask mask
Mix pixels from source_area in source_image, bounding_box pixels in the draw area, and the brush pattern. The method for mixing three pixels into the destination area (i.e., bounding_box) is defined by rop3 (i.e., ternary raster operations). In case scaling of source image is required it will be performed according to scale_mode and before the mixing. If mask is valid it will limit the modified area.
SPICE_MSG_DISPLAY_DRAW_TRANSPARENT
SpiceMsgDisplayBase SPICE_ADDRESS source_image RECT source_area UINT32 transparent_color UINT32 transparent _true_color
SpiceCopy pixels from source_area on source_image to bounding_box on the draw area. In case scaling of source image is required it will use SPICE_IMAGE_SCALE_MODE_NEAREST. Pixels with value equal to the transparent color will be masked out. SpiceTransparent color is provided in two forms: true color (i.e., RGB888) and the color in the original format (i.e., before compression) .
SPICE_MSG_DISPLAY_DRAW_ALPHA_BLEND
SpiceMsgDisplayBase UINT8 alpha SPICE_ADDRESS source_image RECT source_area
Alpha blend source_area of source_image on bounding_box of draw area using alpha value or alternatively per pixel alpha value. In case scaling of source image is required, it will use SPICE_IMAGE_SCALE_MODE_INTERPOLATE mode. Alpha value is defined as 0 is full transparency and 255 is full opacity. Format of source image can be pre-multiplied ARGB8888 for per pixel alpha value.
New RGB color is defined as:
color' = (source_color * alpha) / 255 alpha' = (source_alpha * alpha) / 255 new_color = color' + ((255 - alpha' ) * destination_color) / 255
SPICE_MSG_DISPLAY_DRAW_STROKE
SpiceMsgDisplayBase SPICE_ADDRESS path – address of the PathSegList that defines the path to render SpiceLineAttr attr Bush brush UINT16 fore_mode - foreground rop_descriptor UINT16 back_mode – background rop_descriptor
Render path using brush line attribute and rop descriptors. If the line is styled (i.e., LINE_ATTR_FLAG_STYLED is set in attr.falgs) then background (i.e., inverse of the style) is drawn using back_mode and the foreground is drawn using fore_mode. If the line is not styled, the entire path is rendered using fore_mode.
SPICE_MSG_DISPLAY_DRAW_TEXT
SpiceMsgDisplayBase SPICE_ADDRESS string – address of GlyphString RECT back_area SpiceBrush fore_brush SpiceBrush back_brush UINT16 fore_mode UINT16 back_mode
Render string of glyph on the display area using brush fore_brush and the rop_descriptor fore_mode. If back_area is not empty the renderer fill back_area on the display area prior to rendering the glyph string. back_area is filled using back_brush and the rop_descriptor back_mode.
Video streaming commands
Spice supports the creation of video streams by the server for rendering video content on the client display area. Unlike other rendering commands, the stream data can be compressed using lossy or video specific compression algorithms. It is not required to render video frames as they arrive and it is also allowed to drop video frames. This enables using video frames buffering for having smoother playback and audio synchronization. Audio synchronization is achieved by using time stamp that is attached to audio and video streams. By using video streaming the network traffic can be dramatically reduced. When the stream is created, the server sends create message using SPICE_MSG_DISPLAY_STREAM_CREATE. After the server creates a stream he can send data using SPICE_MSG_DISPLAY_STREAM_DATA, or set new stream clipping by sending clip message using SPICE_MSG_DISPLAY_STREAM_CLIP. Once the server no longer needs the stream, he can send destroy command using SPICE_MSG_DISPLAY_STREAM_DESTROY. The server can also destroy all active streams by sending destroy all message using SPICE_MSG_DISPLAY_STREAM_DESTROY_ALL.
Stream flags
STREAM_FLAG_TOP_DOWN = 1 /* stream frame line order is from top to bottom */
Codec types
STREAM_CODEC_TYPE_MJPEG = 1 /* this stream uses motion JPEG codec */
SPICE_MSG_DISPLAY_STREAM_CREATE, SpiceMsgDisplayStreamCreate
UINT32 id |
id of the new stream. It is the server’s responsibility to manage stream ids |
UINT32 flags |
flags of the stream, any combination of STREAM_FLAG_? |
UINT32 codec_type |
type of codec used for this stream, one of STREAM_CODEC_TYPE_? |
UINT64 reserved |
must be zero |
UINT32 stream_width |
width of the source frame. |
UINT32 stream_height |
height of the source frame |
UINT32 source_width |
actual frame width to use, must be less or equal to stream_width. |
UINT32 source_height |
actual frame height to use, must be less or equal to stream_height. |
RECT destination |
area to render into on the client display area |
SpiceClip clip |
clipping of the stream |
SPICE_MSG_DISPLAY_STREAM_DATA, SpiceMsgDisplayStreamData
UINT32 id |
stream id (i.e., SpiceMsgDisplayStreamCreate.id) |
UINT32 multimedia_time |
frame time stamp |
UINT32 data_size |
stream data size to consume in bytes |
UINT32 pad_size |
additional data padding in bytes |
UINT8[] data |
stream data depending on SpiceMsgDisplayStreamCreate.codec_type. Size of data is ( data_size + pad_size) |
SPICE_MSG_DISPLAY_STREAM_CLIP, SpiceMsgDisplayStreamClip
UINT32 id |
stream id (i.e., SpiceMsgDisplayStreamCreate.id) |
SpiceClip clip – new clipping of the stream
SPICE_MSG_DISPLAY_STREAM_DESTROY, UINT32
UINT32 |
id of stream to destroy |
SPICE_MSG_DISPLAY_STREAM_DESTROY_ALL, VOID
Destroy all active streams
Cache control
Resource type
SPICE_RES_TYPE_PIXMAP = 1
SpiceResourceID
UINT8 type |
type of the resource, one of SPICE_RES_TYPE_? |
UINT64 id |
id of the resource |
SpiceResourceList
UINT16 count |
number of items in resources |
SpiceResourceID[] resources |
list of resources id |
SPICE_MSG_DISPLAY_INVAL_LIST, SpiceResourceList
SpiceResourceList |
list of resources to remove from cache |
SPICE_MSG_DISPLAY_INVAL_ALL_PIXMAPS, SpiceMsgWaitForChannels
Remove all images from the image cache. The client must use SpiceMsgWaitForChannels (for more info see Channel synchronization) to synchronize with other channels before clearing the cache.
SPICE_MSG_DISPLAY_INVAL_PALETTE, UINT64
UINT64 id of palette |
client needs to remove palette with that id from the cache |
SPICE_MSG_DISPLAY_INVAL_ALL_PALETTES, VOID
Remove all palettes from palette cache
Spice protocol defines a set of messages for controlling cursor shape and position on the remote display area, cursor position messages are irrelevant for client mouse mode (see Mouse Modes). Spice protocol also defines a set of messages for managing cursor shape cache on the client site. Client must strictly obey all such instructions. The server sends SPICE_MSG_CURSOR_INIT to set current pointer state (i.e., shape, position, visibility etc.) and to clear shape cache. After the server sends init message it can send any other cursor command except for SPICE_MSG_CURSOR_INIT. The server can send SPICE_MSG_CURSOR_RESET message - this will disable the cursor and reset the cursor cache. After this message the only valid message the server can send is SPICE_MSG_CURSOR_INIT. The relevant remote display area for a cursor channel is the one of the display channel that has the same channel id (i.e., SpiceLinkMess.channel_id).
Server messages
SPICE_MSG_CURSOR_INIT = 101 SPICE_MSG_CURSOR_RESET = 102 SPICE_MSG_CURSOR_SET = 103 SPICE_MSG_CURSOR_MOVE = 104 SPICE_MSG_CURSOR_HIDE = 105 SPICE_MSG_CURSOR_TRAIL = 106 SPICE_MSG_CURSOR_INVAL_ONE = 107 SPICE_MSG_CURSOR_INVAL_ALL = 108
Cursors types
SPICE_CURSOR_TYPE_ALPHA = 0 SPICE_CURSOR_TYPE_MONO = 1 SPICE_CURSOR_TYPE_COLOR4 = 2 SPICE_CURSOR_TYPE_COLOR8 = 3 SPICE_CURSOR_TYPE_COLOR16 = 4 SPICE_CURSOR_TYPE_COLOR24 = 5 SPICE_CURSOR_TYPE_COLOR32 = 6
SpiceCursorHeader
UINT64 unique |
unique identifier of the corresponding cursor shape. It is used for storing and retrieving cursors from the cursor cache. |
UINT16 type |
type of the shape, one of CURSOR_TYPE_? |
UINT16 width |
width of the shape |
UINT16 height |
height of the shape |
UINT16 hot_spot_x |
position of hot spot on x axis |
UINT16 hot_spot_y |
position of hot spot on y axis |
Cursor flags
CURSOR_FLAGS_NONE = 1
set when SpiceCursor (see below) is invalid
CURSOR_CURSOR_FLAGS _CACHE_ME = 2
set when the client should add this shape to the shapes cache. The client will use SpiceCursorHeader.unique as cache key.
CURSOR_FLAGS_FROM_CACHE = 4
set when the client should retrieve the cursor shape, using SpiceCursorHeader.unique as key, from the shapes cache. In this case all fields of SpiceCursorHeader except for unique are invalid.
SpiceCursor
UINT32 flags |
any valid combination of SPICE_CURSOR_FLAGS_? |
SpiceCursorHeader header |
|
UINT8[] data |
actual cursor shape data, the size is determine by width, height and type from SpiceCursorHeader. Next we will describe in detail the shape data format according to cursor type: |
ALPHA, alpha shape |
data contains pre-multiplied ARGB8888 pixmap. Line stride is <width * 4>. |
MONO, monochrome shape |
data contains two bitmaps with size <width> * <height>. The first bitmap is AND mask and the second is XOR mask. Line stride is ALIGN(<width>, 8) / 8. Bits order within every byte is big endian. |
COLOR4, 4 bits per pixel shape |
First data region is pixmap: the stride of the pixmap is ALIGN(width , 2) / 2; every nibble is translated to a color usingthe color palette; Nibble order is big endian. Second data region contain 16 colors palette: each entry is 32 bit RGB color. Third region is a bitmap mask: line stride is ALIGN(<width>, 8) / 8; bits order within every byte is big endian. |
COLOR4, 8 bits per pixel shape |
First data region is pixmap: the stride of the pixmap is <width>; every byte is translated to color using the color palette. Second data region contain 256 colors palette: each entry is 32 bit RGB color. Third region is a bitmap mask: line stride is ALIGN(<width>, 8) / 8; bits order within every byte is big endian. |
COLOR16, 16 bits per pixel shape |
First data region is pixmap: the stride of the pixmap is <width * 2>; every UINT16 is RGB_555. Second region is a bitmap mask: line stride is ALIGN(<width>, 8) / 8; bits order within every byte is big endian. |
COLOR24, 24 bits per pixel shape |
First data region is pixmap: the stride of the pixmap is <width * 3>; every UINT8[3] is RGB_888. Second region is a bitmap mask: line stride is ALIGN(<width>, 8) / 8; bits order within every byte is big endian. |
COLOR32, 32 bits per pixel shape |
First data region is pixmap: the stride of the pixmap is <width * 4>,;every UINT32 is RGB_888. Second region is a bitmap mask: line stride is ALIGN(<width>, 8) / 8; bits order within every byte is big endian. |
For more deatails on drawing the cursor shape see this section
SPICE_MSG_CURSOR_INIT, SpiceMsgCursorInit
POINT16 position |
position of mouse pointer on the relevant display area. Not relevant in client mode. |
UINT16 trail_length |
number of cursors in the trail excluding main cursor. |
UINT16 trail_frequency |
millisecond interval between trail updates. |
UIN8 visible |
if 1, the cursor is visible. If 0, the cursor is invisible. |
SpiceCursor cursor |
current cursor shape |
SPICE_MSG_CURSOR_RESET, VOID
SPICE_MSG_CURSOR_SET, SpiceMsgCursorSet
POINT16 position |
position of mouse pointer on the relevant display area. not relevant in client mode. |
UINT8 visible |
if 1, the cursor is visible. If 0, the cursor is invisible. |
SpiceCursor cursor |
current cursor shape |
SPICE_MSG_CURSOR_MOVE, POINT16
POINT16 |
new mouse position. Not relevant in client mode. This message also implicitly sets cursor visibility to 1. |
SPICE_MSG_CURSOR_HIDE, VOID
Hide pointer on the relevant display area.
SPICE_MSG_CURSOR_TRAIL
UINT16 length |
number of cursors in the trail excluding main cursor. |
UINT16 frequency |
millisecond interval between trail updates |
SPICE_MSG_CURSOR_INVAL_ONE, UINT64
UINT64 |
id of cursor shape to remove from the cursor cache |
SPICE_MSG_CURSOR_INVAL_ALL, VOLD
Clear cursor cache
Drawing the cursor shape according to the cursor type
This section is relevant only for server mouse mode. Cursor shape positioning on the display area is done by placing cursor hot spot on the current cursor position.
Alpha - no spacial handling, just bland the shape on the display area.
Monochrome
For each cleared bit in the AND mask clear the corresponding bits in the relevant pixel on the display area For each set bit in the XOR mask reverse the corresponding bits in the relevant pixel on the display area
Color
If the source color is black and mask bit is set, NOP. Else, if the source color is white and the mask bit is set, reverse all bits in the relevant pixel on the display area. Else, put source color.
Spice supports sending audio streams for playback on the client side. An audio stream is sent by the server in an audio packet using SPICE_MSG_PLAYBACK_DATA message. The content of the audio packet is controlled by the playback mode that the server sends using SPICE_MSG_PLAYBACK_MODE message. The server can start and stop the stream using SPICE_MSG_PLAYBACK_START and SPICE_MSG_PLAYBACK_STOP messages. Sending audio packet is allowed only between start and stop messages. Sending start message is allowed only in stop state and after at least one mode message was sent. Sending a stop message is allowed only during a start state.
Server messages
SPICE_MSG_PLAYBACK_DATA = 101 SPICE_MSG_PLAYBACK_MODE = 102 SPICE_MSG_PLAYBACK_START = 103 SPICE_MSG_PLAYBACK_STOP = 104
Audio format
SPICE_AUDIO_FMT_S16 = 1 /* each channel sample is a 16 bit signed integer */
Playback data mode
Two types of data mode are available: (1) raw PCM data, (2) compressed data in CELT 0_5_1 format (obsolete) and (3) compressed data in OPUS format.
SPICE_AUDIO_DATA_MODE_RAW = 1 SPICE_AUDIO_DATA_MODE_CELT_0_5_1 = 2 SPICE_AUDIO_DATA_MODE_OPUS = 3
Playback channel capabilities
SPICE_PLAYBACK_CAP_CELT_0_5_1 = 0 SPICE_PLAYBACK_CAP_VOLUME = 1 SPICE_PLAYBACK_CAP_LATENCY = 2 SPICE_PLAYBACK_CAP_OPUS = 3
Spice client needs to declare support of OPUS in channel capabilities in order to allow the server to send playback packets in OPUS format.
SPICE_MSG_PLAYBACK_MODE, SpiceMsgPlaybackMode
UINT32 time |
server time stamp |
UINT32 mode |
one of SPICE_AUDIO_DATA_MODE_? |
UINT8[] data |
specific data, content depend on mode |
SPICE_MSG_PLAYBACK_START, SpiceMsgRecordStart
UINT32 channels |
number of audio channels |
UINT32 format |
one of SPICE_AUDIO_FMT_? |
UINT32 frequency |
channel samples per second |
SPICE_MSG_PLAYBACK_DATA, SpiceMsgPlaybackPacket
UINT32 time |
server time stamp |
UINT8[] data |
playback data , content depend on mode |
SPICE_MSG_PLAYBACK_STOP, VOID
Stop current audio playback
Spice supports transmitting of audio captured streams from the client to the server. Spice server starts audio capturing using SPICE_MSG_RECORD_START message. This message instructs the client to start transmitting captured audio . In response, the client sends time stamp of the stream start using SPICE_MSGC_RECORD_START_MARK. After the client sends start mark it can start transmitting audio stream data using SPICE_MSGC_RECORD_DATA. One mode message must be sent by the client before any other message using SPICE_MSGC_RECORD_MODE. This, in order to inform the server on what type of data will be transferred. Mode message can also be transmitted at any other time in order to switch the data type delivered by SPICE_MSGC_RECORD_DATA. The Server can send SPICE_MSG_RECORD_STOP for stopping captured audio streaming. Sending a start message is allowed only while the stream is in stop state. Sending a stop message and data messages is allowed only while the stream is in start state. Sending mark message is allowed only between start message and the first data message.
Server messages
SPICE_MSG_RECORD_START = 101 SPICE_MSG_RECORD_STOP = 102
Client messages
SPICE_MSGC_RECORD_DATA = 101 SPICE_MSGC_RECORD_MODE = 102 SPICE_MSGC_RECORD_START_MARK = 103
Audio format
SPICE_AUDIO_FMT_S16 = 1 /* each channel sample is a 16 bit signed integer */
Record data mode
Two types of data mode are available: (1) raw PCM data (2) compressed data in CELT 0.5.1 format (obsolete) (3) compressed data in OPUS format.
SPICE_AUDIO_DATA_MODE_RAW = 1 SPICE_AUDIO_DATA_MODE_CELT_0_5_1 = 2 SPICE_AUDIO_DATA_MODE_OPUS = 3
Record channel capabilities
SPICE_RECORD_CAP_CELT_0_5_1 = 0 SPICE_RECORD_CAP_VOLUME = 1 SPICE_RECORD_CAP_OPUS = 2
Spice server needs to declare support of OPUS in channel capabilities in order to allow the client to send recorded packets in OPUS format.
SPICE_MSGC_RECORD_MODE, SpiceMsgcRecordMode
UINT32 time |
client time stamp |
UINT32 mode |
one of SPICE_AUDIO_DATA_MODE_? |
UINT8[] data |
specific data, content depend on mode |
SPICE_MSG_RECORD_START, SpiceMsgRecordStart
UINT32 channel |
number of audio channels |
UINT32 format |
one of SPICE_AUDIO_FMT_? |
UINT32 frequency |
channel samples per second |
SPICE_MSGC_RECORD_START_MARK, UINT32
UINT32 |
client time stamp of stream start |
SPICE_MSGC_RECORD_DATA, SpiceMsgcRecordPacket
UINT32 time |
client time stamp |
UINT8[] data |
recorded data , content depend on mode |
SPICE_MSG_RECORD_STOP, VOID
Stop current audio capture