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diff --git a/Documentation/usb/usbip_protocol.rst b/Documentation/usb/usbip_protocol.rst new file mode 100644 index 000000000..988c83216 --- /dev/null +++ b/Documentation/usb/usbip_protocol.rst @@ -0,0 +1,411 @@ +=============== +USB/IP protocol +=============== + +PRELIMINARY DRAFT, MAY CONTAIN MISTAKES! +28 Jun 2011 + +The USB/IP protocol follows a server/client architecture. The server exports the +USB devices and the clients imports them. The device driver for the exported +USB device runs on the client machine. + +The client may ask for the list of the exported USB devices. To get the list the +client opens a TCP/IP connection towards the server, and sends an OP_REQ_DEVLIST +packet on top of the TCP/IP connection (so the actual OP_REQ_DEVLIST may be sent +in one or more pieces at the low level transport layer). The server sends back +the OP_REP_DEVLIST packet which lists the exported USB devices. Finally the +TCP/IP connection is closed. + +:: + + virtual host controller usb host + "client" "server" + (imports USB devices) (exports USB devices) + | | + | OP_REQ_DEVLIST | + | ----------------------------------------------> | + | | + | OP_REP_DEVLIST | + | <---------------------------------------------- | + | | + +Once the client knows the list of exported USB devices it may decide to use one +of them. First the client opens a TCP/IP connection towards the server and +sends an OP_REQ_IMPORT packet. The server replies with OP_REP_IMPORT. If the +import was successful the TCP/IP connection remains open and will be used +to transfer the URB traffic between the client and the server. The client may +send two types of packets: the USBIP_CMD_SUBMIT to submit an URB, and +USBIP_CMD_UNLINK to unlink a previously submitted URB. The answers of the +server may be USBIP_RET_SUBMIT and USBIP_RET_UNLINK respectively. + +:: + + virtual host controller usb host + "client" "server" + (imports USB devices) (exports USB devices) + | | + | OP_REQ_IMPORT | + | ----------------------------------------------> | + | | + | OP_REP_IMPORT | + | <---------------------------------------------- | + | | + | | + | USBIP_CMD_SUBMIT(seqnum = n) | + | ----------------------------------------------> | + | | + | USBIP_RET_SUBMIT(seqnum = n) | + | <---------------------------------------------- | + | . | + | : | + | | + | USBIP_CMD_SUBMIT(seqnum = m) | + | ----------------------------------------------> | + | | + | USBIP_CMD_SUBMIT(seqnum = m+1) | + | ----------------------------------------------> | + | | + | USBIP_CMD_SUBMIT(seqnum = m+2) | + | ----------------------------------------------> | + | | + | USBIP_RET_SUBMIT(seqnum = m) | + | <---------------------------------------------- | + | | + | USBIP_CMD_SUBMIT(seqnum = m+3) | + | ----------------------------------------------> | + | | + | USBIP_RET_SUBMIT(seqnum = m+1) | + | <---------------------------------------------- | + | | + | USBIP_CMD_SUBMIT(seqnum = m+4) | + | ----------------------------------------------> | + | | + | USBIP_RET_SUBMIT(seqnum = m+2) | + | <---------------------------------------------- | + | . | + | : | + | | + | USBIP_CMD_UNLINK | + | ----------------------------------------------> | + | | + | USBIP_RET_UNLINK | + | <---------------------------------------------- | + | | + +The fields are in network (big endian) byte order meaning that the most significant +byte (MSB) is stored at the lowest address. + + +OP_REQ_DEVLIST: + Retrieve the list of exported USB devices. + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 2 | 0x0100 | Binary-coded decimal USBIP version number: v1.0.0 | ++-----------+--------+------------+---------------------------------------------------+ +| 2 | 2 | 0x8005 | Command code: Retrieve the list of exported USB | +| | | | devices. | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | 0x00000000 | Status: unused, shall be set to 0 | ++-----------+--------+------------+---------------------------------------------------+ + +OP_REP_DEVLIST: + Reply with the list of exported USB devices. + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 2 | 0x0100 | Binary-coded decimal USBIP version number: v1.0.0.| ++-----------+--------+------------+---------------------------------------------------+ +| 2 | 2 | 0x0005 | Reply code: The list of exported USB devices. | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | 0x00000000 | Status: 0 for OK | ++-----------+--------+------------+---------------------------------------------------+ +| 8 | 4 | n | Number of exported devices: 0 means no exported | +| | | | devices. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x0C | | | From now on the exported n devices are described, | +| | | | if any. If no devices are exported the message | +| | | | ends with the previous "number of exported | +| | | | devices" field. | ++-----------+--------+------------+---------------------------------------------------+ +| | 256 | | path: Path of the device on the host exporting the| +| | | | USB device, string closed with zero byte, e.g. | +| | | | "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-2" | +| | | | The unused bytes shall be filled with zero | +| | | | bytes. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x10C | 32 | | busid: Bus ID of the exported device, string | +| | | | closed with zero byte, e.g. "3-2". The unused | +| | | | bytes shall be filled with zero bytes. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x12C | 4 | | busnum | ++-----------+--------+------------+---------------------------------------------------+ +| 0x130 | 4 | | devnum | ++-----------+--------+------------+---------------------------------------------------+ +| 0x134 | 4 | | speed | ++-----------+--------+------------+---------------------------------------------------+ +| 0x138 | 2 | | idVendor | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13A | 2 | | idProduct | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13C | 2 | | bcdDevice | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13E | 1 | | bDeviceClass | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13F | 1 | | bDeviceSubClass | ++-----------+--------+------------+---------------------------------------------------+ +| 0x140 | 1 | | bDeviceProtocol | ++-----------+--------+------------+---------------------------------------------------+ +| 0x141 | 1 | | bConfigurationValue | ++-----------+--------+------------+---------------------------------------------------+ +| 0x142 | 1 | | bNumConfigurations | ++-----------+--------+------------+---------------------------------------------------+ +| 0x143 | 1 | | bNumInterfaces | ++-----------+--------+------------+---------------------------------------------------+ +| 0x144 | | m_0 | From now on each interface is described, all | +| | | | together bNumInterfaces times, with the | +| | | | the following 4 fields: | ++-----------+--------+------------+---------------------------------------------------+ +| | 1 | | bInterfaceClass | ++-----------+--------+------------+---------------------------------------------------+ +| 0x145 | 1 | | bInterfaceSubClass | ++-----------+--------+------------+---------------------------------------------------+ +| 0x146 | 1 | | bInterfaceProtocol | ++-----------+--------+------------+---------------------------------------------------+ +| 0x147 | 1 | | padding byte for alignment, shall be set to zero | ++-----------+--------+------------+---------------------------------------------------+ +| 0xC + | | | The second exported USB device starts at i=1 | +| i*0x138 + | | | with the busid field. | +| m_(i-1)*4 | | | | ++-----------+--------+------------+---------------------------------------------------+ + +OP_REQ_IMPORT: + Request to import (attach) a remote USB device. + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 2 | 0x0100 | Binary-coded decimal USBIP version number: v1.0.0 | ++-----------+--------+------------+---------------------------------------------------+ +| 2 | 2 | 0x8003 | Command code: import a remote USB device. | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | 0x00000000 | Status: unused, shall be set to 0 | ++-----------+--------+------------+---------------------------------------------------+ +| 8 | 32 | | busid: the busid of the exported device on the | +| | | | remote host. The possible values are taken | +| | | | from the message field OP_REP_DEVLIST.busid. | +| | | | A string closed with zero, the unused bytes | +| | | | shall be filled with zeros. | ++-----------+--------+------------+---------------------------------------------------+ + +OP_REP_IMPORT: + Reply to import (attach) a remote USB device. + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 2 | 0x0100 | Binary-coded decimal USBIP version number: v1.0.0 | ++-----------+--------+------------+---------------------------------------------------+ +| 2 | 2 | 0x0003 | Reply code: Reply to import. | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | 0x00000000 | Status: | +| | | | | +| | | | - 0 for OK | +| | | | - 1 for error | ++-----------+--------+------------+---------------------------------------------------+ +| 8 | | | From now on comes the details of the imported | +| | | | device, if the previous status field was OK (0), | +| | | | otherwise the reply ends with the status field. | ++-----------+--------+------------+---------------------------------------------------+ +| | 256 | | path: Path of the device on the host exporting the| +| | | | USB device, string closed with zero byte, e.g. | +| | | | "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-2" | +| | | | The unused bytes shall be filled with zero | +| | | | bytes. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x108 | 32 | | busid: Bus ID of the exported device, string | +| | | | closed with zero byte, e.g. "3-2". The unused | +| | | | bytes shall be filled with zero bytes. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x128 | 4 | | busnum | ++-----------+--------+------------+---------------------------------------------------+ +| 0x12C | 4 | | devnum | ++-----------+--------+------------+---------------------------------------------------+ +| 0x130 | 4 | | speed | ++-----------+--------+------------+---------------------------------------------------+ +| 0x134 | 2 | | idVendor | ++-----------+--------+------------+---------------------------------------------------+ +| 0x136 | 2 | | idProduct | ++-----------+--------+------------+---------------------------------------------------+ +| 0x138 | 2 | | bcdDevice | ++-----------+--------+------------+---------------------------------------------------+ +| 0x139 | 1 | | bDeviceClass | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13A | 1 | | bDeviceSubClass | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13B | 1 | | bDeviceProtocol | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13C | 1 | | bConfigurationValue | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13D | 1 | | bNumConfigurations | ++-----------+--------+------------+---------------------------------------------------+ +| 0x13E | 1 | | bNumInterfaces | ++-----------+--------+------------+---------------------------------------------------+ + +USBIP_CMD_SUBMIT: + Submit an URB + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 4 | 0x00000001 | command: Submit an URB | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | | seqnum: the sequence number of the URB to submit | ++-----------+--------+------------+---------------------------------------------------+ +| 8 | 4 | | devid | ++-----------+--------+------------+---------------------------------------------------+ +| 0xC | 4 | | direction: | +| | | | | +| | | | - 0: USBIP_DIR_OUT | +| | | | - 1: USBIP_DIR_IN | ++-----------+--------+------------+---------------------------------------------------+ +| 0x10 | 4 | | ep: endpoint number, possible values are: 0...15 | ++-----------+--------+------------+---------------------------------------------------+ +| 0x14 | 4 | | transfer_flags: possible values depend on the | +| | | | URB transfer type, see below | ++-----------+--------+------------+---------------------------------------------------+ +| 0x18 | 4 | | transfer_buffer_length | ++-----------+--------+------------+---------------------------------------------------+ +| 0x1C | 4 | | start_frame: specify the selected frame to | +| | | | transmit an ISO frame, ignored if URB_ISO_ASAP | +| | | | is specified at transfer_flags | ++-----------+--------+------------+---------------------------------------------------+ +| 0x20 | 4 | | number_of_packets: number of ISO packets | ++-----------+--------+------------+---------------------------------------------------+ +| 0x24 | 4 | | interval: maximum time for the request on the | +| | | | server-side host controller | ++-----------+--------+------------+---------------------------------------------------+ +| 0x28 | 8 | | setup: data bytes for USB setup, filled with | +| | | | zeros if not used | ++-----------+--------+------------+---------------------------------------------------+ +| 0x30 | | | URB data. For ISO transfers the padding between | +| | | | each ISO packets is not transmitted. | ++-----------+--------+------------+---------------------------------------------------+ + + + +-------------------------+------------+---------+-----------+----------+-------------+ + | Allowed transfer_flags | value | control | interrupt | bulk | isochronous | + +=========================+============+=========+===========+==========+=============+ + | URB_SHORT_NOT_OK | 0x00000001 | only in | only in | only in | no | + +-------------------------+------------+---------+-----------+----------+-------------+ + | URB_ISO_ASAP | 0x00000002 | no | no | no | yes | + +-------------------------+------------+---------+-----------+----------+-------------+ + | URB_NO_TRANSFER_DMA_MAP | 0x00000004 | yes | yes | yes | yes | + +-------------------------+------------+---------+-----------+----------+-------------+ + | URB_ZERO_PACKET | 0x00000040 | no | no | only out | no | + +-------------------------+------------+---------+-----------+----------+-------------+ + | URB_NO_INTERRUPT | 0x00000080 | yes | yes | yes | yes | + +-------------------------+------------+---------+-----------+----------+-------------+ + | URB_FREE_BUFFER | 0x00000100 | yes | yes | yes | yes | + +-------------------------+------------+---------+-----------+----------+-------------+ + | URB_DIR_MASK | 0x00000200 | yes | yes | yes | yes | + +-------------------------+------------+---------+-----------+----------+-------------+ + + +USBIP_RET_SUBMIT: + Reply for submitting an URB + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 4 | 0x00000003 | command | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | | seqnum: URB sequence number | ++-----------+--------+------------+---------------------------------------------------+ +| 8 | 4 | | devid | ++-----------+--------+------------+---------------------------------------------------+ +| 0xC | 4 | | direction: | +| | | | | +| | | | - 0: USBIP_DIR_OUT | +| | | | - 1: USBIP_DIR_IN | ++-----------+--------+------------+---------------------------------------------------+ +| 0x10 | 4 | | ep: endpoint number | ++-----------+--------+------------+---------------------------------------------------+ +| 0x14 | 4 | | status: zero for successful URB transaction, | +| | | | otherwise some kind of error happened. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x18 | 4 | n | actual_length: number of URB data bytes | ++-----------+--------+------------+---------------------------------------------------+ +| 0x1C | 4 | | start_frame: for an ISO frame the actually | +| | | | selected frame for transmit. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x20 | 4 | | number_of_packets | ++-----------+--------+------------+---------------------------------------------------+ +| 0x24 | 4 | | error_count | ++-----------+--------+------------+---------------------------------------------------+ +| 0x28 | 8 | | setup: data bytes for USB setup, filled with | +| | | | zeros if not used | ++-----------+--------+------------+---------------------------------------------------+ +| 0x30 | n | | URB data bytes. For ISO transfers the padding | +| | | | between each ISO packets is not transmitted. | ++-----------+--------+------------+---------------------------------------------------+ + +USBIP_CMD_UNLINK: + Unlink an URB + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 4 | 0x00000002 | command: URB unlink command | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | | seqnum: URB sequence number to unlink: | +| | | | | +| | | | FIXME: | +| | | | is this so? | ++-----------+--------+------------+---------------------------------------------------+ +| 8 | 4 | | devid | ++-----------+--------+------------+---------------------------------------------------+ +| 0xC | 4 | | direction: | +| | | | | +| | | | - 0: USBIP_DIR_OUT | +| | | | - 1: USBIP_DIR_IN | ++-----------+--------+------------+---------------------------------------------------+ +| 0x10 | 4 | | ep: endpoint number: zero | ++-----------+--------+------------+---------------------------------------------------+ +| 0x14 | 4 | | seqnum: the URB sequence number given previously | +| | | | at USBIP_CMD_SUBMIT.seqnum field | ++-----------+--------+------------+---------------------------------------------------+ +| 0x30 | n | | URB data bytes. For ISO transfers the padding | +| | | | between each ISO packets is not transmitted. | ++-----------+--------+------------+---------------------------------------------------+ + +USBIP_RET_UNLINK: + Reply for URB unlink + ++-----------+--------+------------+---------------------------------------------------+ +| Offset | Length | Value | Description | ++===========+========+============+===================================================+ +| 0 | 4 | 0x00000004 | command: reply for the URB unlink command | ++-----------+--------+------------+---------------------------------------------------+ +| 4 | 4 | | seqnum: the unlinked URB sequence number | ++-----------+--------+------------+---------------------------------------------------+ +| 8 | 4 | | devid | ++-----------+--------+------------+---------------------------------------------------+ +| 0xC | 4 | | direction: | +| | | | | +| | | | - 0: USBIP_DIR_OUT | +| | | | - 1: USBIP_DIR_IN | ++-----------+--------+------------+---------------------------------------------------+ +| 0x10 | 4 | | ep: endpoint number | ++-----------+--------+------------+---------------------------------------------------+ +| 0x14 | 4 | | status: This is the value contained in the | +| | | | urb->status in the URB completition handler. | +| | | | | +| | | | FIXME: | +| | | | a better explanation needed. | ++-----------+--------+------------+---------------------------------------------------+ +| 0x30 | n | | URB data bytes. For ISO transfers the padding | +| | | | between each ISO packets is not transmitted. | ++-----------+--------+------------+---------------------------------------------------+ |