Message-ID: <Zpgxnszbsf8_uEzf@pengutronix.de>
Date: Wed, 17 Jul 2024 23:03:26 +0200
From: Michael Grzeschik <mgr@...gutronix.de>
To: Andrzej Pietrasiewicz <andrzej.p@...labora.com>
Cc: Eric Van Hensbergen <ericvh@...nel.org>,
	Latchesar Ionkov <lucho@...kov.net>,
	Dominique Martinet <asmadeus@...ewreck.org>,
	Christian Schoenebeck <linux_oss@...debyte.com>,
	Jonathan Corbet <corbet@....net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	v9fs@...ts.linux.dev, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
	kernel@...gutronix.de, Jan Luebbe <jlu@...gutronix.de>
Subject: Re: [PATCH v6 3/3] tools: usb: p9_fwd: add usb gadget packet
 forwarder script

Hi Andrzej,

On Mon, Jun 17, 2024 at 01:46:01PM +0200, Michael Grzeschik wrote:
>On Thu, Jun 06, 2024 at 10:19:33AM +0200, Andrzej Pietrasiewicz wrote:
>>Hi,
>>
>>W dniu 5.06.2024 o 15:32, Michael Grzeschik pisze:
>>>This patch is adding an small python tool to forward 9pfs requests
>>>from the USB gadget to an existing 9pfs TCP server. Since currently all
>>>9pfs servers lack support for the usb transport this tool is an useful
>>>helper to get started.
>>>
>>>Refer the Documentation section "USBG Example" in
>>>Documentation/filesystems/9p.rst on how to use it.
>>>
>>>Signed-off-by: Jan Luebbe <jlu@...gutronix.de>
>>>Signed-off-by: Michael Grzeschik <m.grzeschik@...gutronix.de>
>>>
>>
>>This time --id alone worked for me (as well as --id combined with --path)
>>but --path alone did not:
>
>This is currently right and expected. Why is using path alone of any
>more use? Since you could then grab any device with two bulk endpoints
>without even ensuring that it is supposed to behave as expected with
>this script.

Ping!

Can this series move on?

Regards,
Michael

>>$ sudo python3 tools/usb/p9_fwd.py --id 0xabcd:0xef01 list
>>Bus | Addr | Manufacturer     | Product          | ID        | Path
>>--- | ---- | ---------------- | ---------------- | --------- | ----
>> 3 |   39 | unknown          | unknown          | abcd:ef01 | 3-1.3.3.5.4
>>
>>$ sudo python3 tools/usb/p9_fwd.py --id 0xabcd:0xef01 connect -p 9999
>>2024-06-06 10:14:45,368 INFO     found device: 3/39 located at 3-1.3.3.5.4
>>2024-06-06 10:14:45,369 INFO     claiming interface:
>>   INTERFACE 0: Vendor Specific ===========================
>>    bLength            :    0x9 (9 bytes)
>>    bDescriptorType    :    0x4 Interface
>>    bInterfaceNumber   :    0x0
>>    bAlternateSetting  :    0x0
>>    bNumEndpoints      :    0x2
>>    bInterfaceClass    :   0xff Vendor Specific
>>    bInterfaceSubClass :   0xff
>>    bInterfaceProtocol :    0x9
>>    iInterface         :    0x1 usb9pfs input to output
>>     ENDPOINT 0x81: Bulk IN ===============================
>>      bLength          :    0x7 (7 bytes)
>>      bDescriptorType  :    0x5 Endpoint
>>      bEndpointAddress :   0x81 IN
>>      bmAttributes     :    0x2 Bulk
>>      wMaxPacketSize   :  0x200 (512 bytes)
>>      bInterval        :    0x0
>>     ENDPOINT 0x1: Bulk OUT ===============================
>>      bLength          :    0x7 (7 bytes)
>>      bDescriptorType  :    0x5 Endpoint
>>      bEndpointAddress :    0x1 OUT
>>      bmAttributes     :    0x2 Bulk
>>      wMaxPacketSize   :  0x200 (512 bytes)
>>      bInterval        :    0x0
>>2024-06-06 10:14:45,370 INFO     interface claimed
>>2024-06-06 10:14:45,370 INFO     connected to server
>>^C
>>
>>$ sudo python3 tools/usb/p9_fwd.py --path 3-1.3.3.5.4 connect -p 9999
>>Traceback (most recent call last):
>> File "/home/ap/Collabora/kernel-rk/tools/usb/p9_fwd.py", line 243, in <module>
>>   main()
>> File "/home/ap/Collabora/kernel-rk/tools/usb/p9_fwd.py", line 239, in main
>>   args.func(args)
>> File "/home/ap/Collabora/kernel-rk/tools/usb/p9_fwd.py", line 190, in connect
>>   f = Forwarder(server=(args.server, args.port), vid=vid, pid=pid, path=args.path)
>> File "/home/ap/Collabora/kernel-rk/tools/usb/p9_fwd.py", line 60, in __init__
>>   raise ValueError("Device not found")
>>ValueError: Device not found
>>
>>
>>>---
>>>v5 -> v6:
>>>  - set path parameter to None when unused
>>>v4 -> v5:
>>>  - updated documentation for new subcommands list/connect
>>>  - run ruff format
>>>  - make vid and pid parameterized
>>>  - add list as subcommand to scan for devices
>>>  - move connect to extra subcommand
>>>v3 -> v4: -
>>>v2 -> v3: -
>>>v1 -> v2:
>>>  - added usbg 9pfs detailed instructions to 9p.rst doc
>>>---
>>> Documentation/filesystems/9p.rst |  41 +++++++
>>> tools/usb/p9_fwd.py              | 243 +++++++++++++++++++++++++++++++++++++++
>>> 2 files changed, 284 insertions(+)
>>>
>>>diff --git a/Documentation/filesystems/9p.rst b/Documentation/filesystems/9p.rst
>>>index 10cf79dc287f8..2cc85f3e8659f 100644
>>>--- a/Documentation/filesystems/9p.rst
>>>+++ b/Documentation/filesystems/9p.rst
>>>@@ -67,6 +67,47 @@ To mount a 9p FS on a USB Host accessible via the gadget as root filesystem::
>>> where <device> is the tag associated by the usb gadget transport.
>>> It is defined by the configfs instance name.
>>>+USBG Example
>>>+============
>>>+
>>>+The USB host exports a filesystem, while the gadget on the USB device
>>>+side makes it mountable.
>>>+
>>>+Diod (9pfs server) and the forwarder are on the development host, where
>>>+the root filesystem is actually stored. The gadget is initialized during
>>>+boot (or later) on the embedded board. Then the forwarder will find it
>>>+on the USB bus and start forwarding requests.
>>>+
>>>+In this case the 9p requests come from the device and are handled by the
>>>+host. The reason is that USB device ports are normally not available on
>>>+PCs, so a connection in the other direction would not work.
>>>+
>>>+When using the usbg transport, for now there is no native usb host
>>>+service capable to handle the requests from the gadget driver. For
>>>+this we have to use the extra python tool p9_fwd.py from tools/usb.
>>>+
>>>+Just start the 9pfs capable network server like diod/nfs-ganesha e.g.:
>>>+
>>>+        $ diod -f -n -d 0 -S -l 0.0.0.0:9999 -e $PWD
>>>+
>>>+Optionaly scan your bus if there are more then one usbg gadgets to find their path:
>>>+
>>>+        $ python $kernel_dir/tools/usb/p9_fwd.py list
>>>+
>>>+        Bus | Addr | Manufacturer     | Product          | ID        | Path
>>>+        --- | ---- | ---------------- | ---------------- | --------- | ----
>>>+          2 |   67 | unknown          | unknown          | 1d6b:0109 | 2-1.1.2
>>>+          2 |   68 | unknown          | unknown          | 1d6b:0109 | 2-1.1.3
>>>+
>>>+Then start the python transport:
>>>+
>>>+        $ python $kernel_dir/tools/usb/p9_fwd.py --path 2-1.1.2 connect -p 9999
>>>+
>>>+After that the gadget driver can be used as described above.
>>>+
>>>+One use-case is to use it as an alternative to NFS root booting during
>>>+the development of embedded Linux devices.
>>>+
>>> Options
>>> =======
>>>diff --git a/tools/usb/p9_fwd.py b/tools/usb/p9_fwd.py
>>>new file mode 100755
>>>index 0000000000000..12c76cbb046b7
>>>--- /dev/null
>>>+++ b/tools/usb/p9_fwd.py
>>>@@ -0,0 +1,243 @@
>>>+#!/usr/bin/env python3
>>>+# SPDX-License-Identifier: GPL-2.0
>>>+
>>>+import argparse
>>>+import errno
>>>+import logging
>>>+import socket
>>>+import struct
>>>+import time
>>>+
>>>+import usb.core
>>>+import usb.util
>>>+
>>>+
>>>+def path_from_usb_dev(dev):
>>>+    """Takes a pyUSB device as argument and returns a string.
>>>+    The string is a Path representation of the position of the USB device on the USB bus tree.
>>>+
>>>+    This path is used to find a USB device on the bus or all devices connected to a HUB.
>>>+    The path is made up of the number of the USB controller followed be the ports of the HUB tree."""
>>>+    if dev.port_numbers:
>>>+        dev_path = ".".join(str(i) for i in dev.port_numbers)
>>>+        return f"{dev.bus}-{dev_path}"
>>>+    return ""
>>>+
>>>+
>>>+HEXDUMP_FILTER = "".join(chr(x).isprintable() and chr(x) or "." for x in range(128)) + "." * 128
>>>+
>>>+
>>>+class Forwarder:
>>>+    @staticmethod
>>>+    def _log_hexdump(data):
>>>+        if not logging.root.isEnabledFor(logging.TRACE):
>>>+            return
>>>+        L = 16
>>>+        for c in range(0, len(data), L):
>>>+            chars = data[c : c + L]
>>>+            dump = " ".join(f"{x:02x}" for x in chars)
>>>+            printable = "".join(HEXDUMP_FILTER[x] for x in chars)
>>>+            line = f"{c:08x}  {dump:{L*3}s} |{printable:{L}s}|"
>>>+            logging.root.log(logging.TRACE, "%s", line)
>>>+
>>>+    def __init__(self, server, vid, pid, path):
>>>+        self.stats = {
>>>+            "c2s packets": 0,
>>>+            "c2s bytes": 0,
>>>+            "s2c packets": 0,
>>>+            "s2c bytes": 0,
>>>+        }
>>>+        self.stats_logged = time.monotonic()
>>>+
>>>+        def find_filter(dev):
>>>+            dev_path = path_from_usb_dev(dev)
>>>+            if path is not None:
>>>+                return dev_path == path
>>>+            return True
>>>+
>>>+        dev = usb.core.find(idVendor=vid, idProduct=pid, custom_match=find_filter)
>>>+        if dev is None:
>>>+            raise ValueError("Device not found")
>>>+
>>>+        logging.info(f"found device: {dev.bus}/{dev.address} located at {path_from_usb_dev(dev)}")
>>>+
>>>+        # dev.set_configuration() is not necessary since g_multi has only one
>>>+        usb9pfs = None
>>>+        # g_multi adds 9pfs as last interface
>>>+        cfg = dev.get_active_configuration()
>>>+        for intf in cfg:
>>>+            # we have to detach the usb-storage driver from multi gadget since
>>>+            # stall option could be set, which will lead to spontaneous port
>>>+            # resets and our transfers will run dead
>>>+            if intf.bInterfaceClass == 0x08:
>>>+                if dev.is_kernel_driver_active(intf.bInterfaceNumber):
>>>+                    dev.detach_kernel_driver(intf.bInterfaceNumber)
>>>+
>>>+            if intf.bInterfaceClass == 0xFF and intf.bInterfaceSubClass == 0xFF and intf.bInterfaceProtocol == 0x09:
>>>+                usb9pfs = intf
>>>+        if usb9pfs is None:
>>>+            raise ValueError("Interface not found")
>>>+
>>>+        logging.info(f"claiming interface:\n{usb9pfs}")
>>>+        usb.util.claim_interface(dev, usb9pfs.bInterfaceNumber)
>>>+        ep_out = usb.util.find_descriptor(
>>>+            usb9pfs,
>>>+            custom_match=lambda e: usb.util.endpoint_direction(e.bEndpointAddress) == usb.util.ENDPOINT_OUT,
>>>+        )
>>>+        assert ep_out is not None
>>>+        ep_in = usb.util.find_descriptor(
>>>+            usb9pfs,
>>>+            custom_match=lambda e: usb.util.endpoint_direction(e.bEndpointAddress) == usb.util.ENDPOINT_IN,
>>>+        )
>>>+        assert ep_in is not None
>>>+        logging.info("interface claimed")
>>>+
>>>+        self.ep_out = ep_out
>>>+        self.ep_in = ep_in
>>>+        self.dev = dev
>>>+
>>>+        # create and connect socket
>>>+        self.s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>>>+        self.s.connect(server)
>>>+
>>>+        logging.info("connected to server")
>>>+
>>>+    def c2s(self):
>>>+        """forward a request from the USB client to the TCP server"""
>>>+        data = None
>>>+        while data is None:
>>>+            try:
>>>+                logging.log(logging.TRACE, "c2s: reading")
>>>+                data = self.ep_in.read(self.ep_in.wMaxPacketSize)
>>>+            except usb.core.USBTimeoutError:
>>>+                logging.log(logging.TRACE, "c2s: reading timed out")
>>>+                continue
>>>+            except usb.core.USBError as e:
>>>+                if e.errno == errno.EIO:
>>>+                    logging.debug("c2s: reading failed with %s, retrying", repr(e))
>>>+                    time.sleep(0.5)
>>>+                    continue
>>>+                logging.error("c2s: reading failed with %s, aborting", repr(e))
>>>+                raise
>>>+        size = struct.unpack("<I", data[:4])[0]
>>>+        while len(data) < size:
>>>+            data += self.ep_in.read(size - len(data))
>>>+        logging.log(logging.TRACE, "c2s: writing")
>>>+        self._log_hexdump(data)
>>>+        self.s.send(data)
>>>+        logging.debug("c2s: forwarded %i bytes", size)
>>>+        self.stats["c2s packets"] += 1
>>>+        self.stats["c2s bytes"] += size
>>>+
>>>+    def s2c(self):
>>>+        """forward a response from the TCP server to the USB client"""
>>>+        logging.log(logging.TRACE, "s2c: reading")
>>>+        data = self.s.recv(4)
>>>+        size = struct.unpack("<I", data[:4])[0]
>>>+        while len(data) < size:
>>>+            data += self.s.recv(size - len(data))
>>>+        logging.log(logging.TRACE, "s2c: writing")
>>>+        self._log_hexdump(data)
>>>+        while data:
>>>+            written = self.ep_out.write(data)
>>>+            assert written > 0
>>>+            data = data[written:]
>>>+        if size % self.ep_out.wMaxPacketSize == 0:
>>>+            logging.log(logging.TRACE, "sending zero length packet")
>>>+            self.ep_out.write(b"")
>>>+        logging.debug("s2c: forwarded %i bytes", size)
>>>+        self.stats["s2c packets"] += 1
>>>+        self.stats["s2c bytes"] += size
>>>+
>>>+    def log_stats(self):
>>>+        logging.info("statistics:")
>>>+        for k, v in self.stats.items():
>>>+            logging.info(f"  {k+':':14s} {v}")
>>>+
>>>+    def log_stats_interval(self, interval=5):
>>>+        if (time.monotonic() - self.stats_logged) < interval:
>>>+            return
>>>+
>>>+        self.log_stats()
>>>+        self.stats_logged = time.monotonic()
>>>+
>>>+
>>>+def try_get_usb_str(dev, name):
>>>+    try:
>>>+        with open(f"/sys/bus/usb/devices/{dev.bus}-{dev.address}/{name}") as f:
>>>+            return f.read().strip()
>>>+    except FileNotFoundError:
>>>+        return None
>>>+
>>>+
>>>+def list_usb(args):
>>>+    vid, pid = [int(x, 16) for x in args.id.split(":", 1)]
>>>+
>>>+    print("Bus | Addr | Manufacturer     | Product          | ID        | Path")
>>>+    print("--- | ---- | ---------------- | ---------------- | --------- | ----")
>>>+    for dev in usb.core.find(find_all=True, idVendor=vid, idProduct=pid):
>>>+        path = path_from_usb_dev(dev) or ""
>>>+        manufacturer = try_get_usb_str(dev, "manufacturer") or "unknown"
>>>+        product = try_get_usb_str(dev, "product") or "unknown"
>>>+        print(
>>>+            f"{dev.bus:3} | {dev.address:4} | {manufacturer:16} | {product:16} | {dev.idVendor:04x}:{dev.idProduct:04x} | {path:18}"
>>>+        )
>>>+
>>>+
>>>+def connect(args):
>>>+    vid, pid = [int(x, 16) for x in args.id.split(":", 1)]
>>>+
>>>+    f = Forwarder(server=(args.server, args.port), vid=vid, pid=pid, path=args.path)
>>>+
>>>+    try:
>>>+        while True:
>>>+            f.c2s()
>>>+            f.s2c()
>>>+            f.log_stats_interval()
>>>+    finally:
>>>+        f.log_stats()
>>>+
>>>+
>>>+def main():
>>>+    parser = argparse.ArgumentParser(
>>>+        description="Forward 9PFS requests from USB to TCP",
>>>+    )
>>>+
>>>+    parser.add_argument("--id", type=str, default="1d6b:0109", help="vid:pid of target device")
>>>+    parser.add_argument("--path", type=str, required=False, help="path of target device")
>>>+    parser.add_argument("-v", "--verbose", action="count", default=0)
>>>+
>>>+    subparsers = parser.add_subparsers()
>>>+    subparsers.required = True
>>>+    subparsers.dest = "command"
>>>+
>>>+    parser_list = subparsers.add_parser("list", help="List all connected 9p gadgets")
>>>+    parser_list.set_defaults(func=list_usb)
>>>+
>>>+    parser_connect = subparsers.add_parser(
>>>+        "connect", help="Forward messages between the usb9pfs gadget and the 9p server"
>>>+    )
>>>+    parser_connect.set_defaults(func=connect)
>>>+    connect_group = parser_connect.add_argument_group()
>>>+    connect_group.required = True
>>>+    parser_connect.add_argument("-s", "--server", type=str, default="127.0.0.1", help="server hostname")
>>>+    parser_connect.add_argument("-p", "--port", type=int, default=564, help="server port")
>>>+
>>>+    args = parser.parse_args()
>>>+
>>>+    logging.TRACE = logging.DEBUG - 5
>>>+    logging.addLevelName(logging.TRACE, "TRACE")
>>>+
>>>+    if args.verbose >= 2:
>>>+        level = logging.TRACE
>>>+    elif args.verbose:
>>>+        level = logging.DEBUG
>>>+    else:
>>>+        level = logging.INFO
>>>+    logging.basicConfig(level=level, format="%(asctime)-15s %(levelname)-8s %(message)s")
>>>+
>>>+    args.func(args)
>>>+
>>>+
>>>+if __name__ == "__main__":
>>>+    main()
>>>
>>
>>
>
>-- 
>Pengutronix e.K.                           |                             |
>Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |



-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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