new maxusb library

[goodfet] / client / USBInterface.py

diff --git a/client/USBInterface.py b/client/USBInterface.py
new file mode 100644 (file)
index 0000000..0cedd6b
--- /dev/null
+++ b/client/USBInterface.py
@@ -0,0 +1,82 @@
+# USBInterface.py
+#
+# Contains class definition for USBInterface.
+
+from USB import *
+
+class USBInterface:
+    name = "generic USB interface"
+
+    def __init__(self, interface_number, interface_alternate, interface_class,
+            interface_subclass, interface_protocol, interface_string_index,
+            verbose=0, endpoints=[], descriptors={}):
+
+        self.number = interface_number
+        self.alternate = interface_alternate
+        self.iclass = interface_class
+        self.subclass = interface_subclass
+        self.protocol = interface_protocol
+        self.string_index = interface_string_index
+
+        self.endpoints = endpoints
+        self.descriptors = descriptors
+
+        self.verbose = verbose
+
+        self.descriptors[USB.desc_type_interface] = self.get_descriptor
+
+        self.request_handlers = {
+            6 : self.handle_get_descriptor_request
+        }
+
+    # USB 2.0 specification, section 9.4.3 (p 281 of pdf)
+    # HACK: blatant copypasta from USBDevice pains me deeply
+    def handle_get_descriptor_request(self, req):
+        dtype  = (req.value >> 8) & 0xff
+        dindex = req.value & 0xff
+        lang   = req.index
+        n      = req.length
+
+        response = None
+
+        if self.verbose > 2:
+            print(self.name, ("received GET_DESCRIPTOR req %d, index %d, " \
+                    + "language 0x%04x, length %d") \
+                    % (dtype, dindex, lang, n))
+
+        # TODO: handle KeyError
+        response = self.descriptors[dtype]
+        if callable(response):
+            response = response(dindex)
+
+        if response:
+            n = min(n, len(response))
+            self.device.maxusb_app.send_on_endpoint(0, response[:n])
+
+            if self.verbose > 5:
+                print(self.name, "sent", n, "bytes in response")
+
+    # Table 9-12 of USB 2.0 spec (pdf page 296)
+    def get_descriptor(self):
+
+        d = bytearray([
+                9,          # length of descriptor in bytes
+                4,          # descriptor type 4 == interface
+                self.number,
+                self.alternate,
+                len(self.endpoints),
+                self.iclass,
+                self.subclass,
+                self.protocol,
+                self.string_index
+        ])
+
+        if self.iclass:
+            iclass_desc_num = USB.interface_class_to_descriptor_type(self.iclass)
+            d += self.descriptors[iclass_desc_num]
+
+        for e in self.endpoints:
+            d += e.get_descriptor()
+
+        return d
+