1 files changed, 243 insertions, 0 deletions
diff --git a/tools/usb/p9_fwd.py b/tools/usb/p9_fwd.py
new file mode 100755
index 000000000000..12c76cbb046b
--- /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()