decoders/usb_request/pd.py

   1 ##
   2 ## This file is part of the libsigrokdecode project.
   3 ##
   4 ## Copyright (C) 2015 Stefan Brüns <stefan.bruens@rwth-aachen.de>
   5 ##
   6 ## This program is free software; you can redistribute it and/or modify
   7 ## it under the terms of the GNU General Public License as published by
   8 ## the Free Software Foundation; either version 2 of the License, or
   9 ## (at your option) any later version.
  10 ##
  11 ## This program is distributed in the hope that it will be useful,
  12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ## GNU General Public License for more details.
  15 ##
  16 ## You should have received a copy of the GNU General Public License
  17 ## along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 ##
  19
  20 import sigrokdecode as srd
  21 import struct
  22
  23 class SamplerateError(Exception):
  24     pass
  25
  26 class pcap_usb_pkt():
  27     # Linux usbmon format, see Documentation/usb/usbmon.txt
  28     h  = b'\x00\x00\x00\x00' # ID part 1
  29     h += b'\x00\x00\x00\x00' # ID part 2
  30     h += b'C'                # 'S'ubmit / 'C'omplete / 'E'rror
  31     h += b'\x03'             # ISO (0), Intr, Control, Bulk (3)
  32     h += b'\x00'             # Endpoint
  33     h += b'\x00'             # Device address
  34     h += b'\x00\x00'         # Bus number
  35     h += b'-'                # Setup tag - 0: Setup present, '-' otherwise
  36     h += b'<'                # Data tag - '<' no data, 0 otherwise
  37     # Timestamp
  38     h += b'\x00\x00\x00\x00' # TS seconds part 1
  39     h += b'\x00\x00\x00\x00' # TS seconds part 2
  40     h += b'\x00\x00\x00\x00' # TS useconds
  41     #
  42     h += b'\x00\x00\x00\x00' # Status 0: OK
  43     h += b'\x00\x00\x00\x00' # URB length
  44     h += b'\x00\x00\x00\x00' # Data length
  45     # Setup packet data, valid if setup tag == 0
  46     h += b'\x00'             # bmRequestType
  47     h += b'\x00'             # bRequest
  48     h += b'\x00\x00'         # wValue
  49     h += b'\x00\x00'         # wIndex
  50     h += b'\x00\x00'         # wLength
  51     #
  52     h += b'\x00\x00\x00\x00' # ISO/interrupt interval
  53     h += b'\x00\x00\x00\x00' # ISO start frame
  54     h += b'\x00\x00\x00\x00' # URB flags
  55     h += b'\x00\x00\x00\x00' # Number of ISO descriptors
  56
  57     def __init__(self, req, ts, is_submit):
  58         self.header = bytearray(pcap_usb_pkt.h)
  59         self.data = b''
  60         self.set_urbid(req['id'])
  61         self.set_urbtype('S' if is_submit else 'C')
  62         self.set_timestamp(ts)
  63         self.set_addr_ep(req['addr'], req['ep'])
  64         if req['type'] in ('SETUP IN', 'SETUP OUT'):
  65             self.set_transfertype(2) # Control
  66             self.set_setup(req['setup_data'])
  67         if req['type'] in ('BULK IN'):
  68             self.set_addr_ep(req['addr'], 0x80 | req['ep'])
  69         self.set_data(req['data'])
  70
  71     def set_urbid(self, urbid):
  72         self.header[4:8] = struct.pack('>I', urbid)
  73
  74     def set_urbtype(self, urbtype):
  75         self.header[8] = ord(urbtype)
  76
  77     def set_transfertype(self, transfertype):
  78         self.header[9] = transfertype
  79
  80     def set_addr_ep(self, addr, ep):
  81         self.header[11] = addr
  82         self.header[10] = ep
  83
  84     def set_timestamp(self, ts):
  85         self.timestamp = ts
  86         self.header[20:24] = struct.pack('>I', ts[0]) # seconds
  87         self.header[24:28] = struct.pack('>I', ts[1]) # microseconds
  88
  89     def set_data(self, data):
  90         self.data = data
  91         self.header[15] = 0
  92         self.header[36:40] = struct.pack('>I', len(data))
  93
  94     def set_setup(self, data):
  95         self.header[14] = 0
  96         self.header[40:48] = data
  97
  98     def packet(self):
  99         return bytes(self.header) + bytes(self.data)
 100
 101     def record_header(self):
 102         # See https://wiki.wireshark.org/Development/LibpcapFileFormat.
 103         (secs, usecs) = self.timestamp
 104         h  = struct.pack('>I', secs) # TS seconds
 105         h += struct.pack('>I', usecs) # TS microseconds
 106         # No truncation, so both lengths are the same.
 107         h += struct.pack('>I', len(self)) # Captured len (usb hdr + data)
 108         h += struct.pack('>I', len(self)) # Original len
 109         return h
 110
 111     def __len__(self):
 112         return 64 + len(self.data)
 113
 114 class Decoder(srd.Decoder):
 115     api_version = 3
 116     id = 'usb_request'
 117     name = 'USB request'
 118     longname = 'Universal Serial Bus (LS/FS) transaction/request'
 119     desc = 'USB (low-speed/full-speed) transaction/request protocol.'
 120     license = 'gplv2+'
 121     inputs = ['usb_packet']
 122     outputs = ['usb_request']
 123     options = (
 124         {'id': 'in_request_start', 'desc': 'Start IN requests on',
 125             'default': 'submit', 'values': ('submit', 'first-ack')},
 126     )
 127     tags = ['PC']
 128     annotations = (
 129         ('request-setup-read', 'Setup: Device-to-host'),
 130         ('request-setup-write', 'Setup: Host-to-device'),
 131         ('request-bulk-read', 'Bulk: Device-to-host'),
 132         ('request-bulk-write', 'Bulk: Host-to-device'),
 133         ('error', 'Unexpected packet'),
 134     )
 135     annotation_rows = (
 136         ('request-setup', 'USB SETUP', (0, 1)),
 137         ('request-in', 'USB BULK IN', (2,)),
 138         ('request-out', 'USB BULK OUT', (3,)),
 139         ('errors', 'Errors', (4,)),
 140     )
 141     binary = (
 142         ('pcap', 'PCAP format'),
 143     )
 144
 145     def __init__(self):
 146         self.reset()
 147
 148     def reset(self):
 149         self.samplerate = None
 150         self.request = {}
 151         self.request_id = 0
 152         self.transaction_state = 'IDLE'
 153         self.ss_transaction = None
 154         self.es_transaction = None
 155         self.transaction_ep = None
 156         self.transaction_addr = None
 157         self.wrote_pcap_header = False
 158
 159     def putr(self, ss, es, data):
 160         self.put(ss, es, self.out_ann, data)
 161
 162     def putb(self, ts, data):
 163         self.put(ts, ts, self.out_binary, data)
 164
 165     def pcap_global_header(self):
 166         # See https://wiki.wireshark.org/Development/LibpcapFileFormat.
 167         h  = b'\xa1\xb2\xc3\xd4' # Magic, indicate microsecond ts resolution
 168         h += b'\x00\x02'         # Major version 2
 169         h += b'\x00\x04'         # Minor version 4
 170         h += b'\x00\x00\x00\x00' # Correction vs. UTC, seconds
 171         h += b'\x00\x00\x00\x00' # Timestamp accuracy
 172         h += b'\xff\xff\xff\xff' # Max packet len
 173         # LINKTYPE_USB_LINUX_MMAPPED 220
 174         # Linux usbmon format, see Documentation/usb/usbmon.txt.
 175         h += b'\x00\x00\x00\xdc' # Link layer
 176         return h
 177
 178     def metadata(self, key, value):
 179         if key == srd.SRD_CONF_SAMPLERATE:
 180             self.samplerate = value
 181             if self.samplerate:
 182                 self.secs_per_sample = float(1) / float(self.samplerate)
 183
 184     def start(self):
 185         self.out_binary = self.register(srd.OUTPUT_BINARY)
 186         self.out_ann = self.register(srd.OUTPUT_ANN)
 187         self.in_request_start = self.options['in_request_start']
 188
 189     def handle_transfer(self):
 190         request_started = 0
 191         request_end = self.handshake in ('ACK', 'STALL', 'timeout')
 192         ep = self.transaction_ep
 193         addr = self.transaction_addr
 194
 195         # Handle protocol STALLs, condition lasts until next SETUP transfer (8.5.3.4)
 196         if self.transaction_type == 'SETUP' and (addr, ep) in self.request:
 197             request = self.request[(addr,ep)]
 198             if request['type'] in ('SETUP IN', 'SETUP OUT'):
 199                 request['es'] = self.ss_transaction
 200                 self.handle_request(0, 1)
 201
 202         if not (addr, ep) in self.request:
 203             self.request[(addr, ep)] = {'setup_data': [], 'data': [],
 204                 'type': None, 'ss': self.ss_transaction, 'es': None,
 205                 'ss_data': None, 'id': self.request_id, 'addr': addr, 'ep': ep}
 206             self.request_id += 1
 207             request_started = 1
 208         request = self.request[(addr,ep)]
 209
 210         if request_end:
 211             request['es'] = self.es_transaction
 212             request['handshake'] = self.handshake
 213
 214         # BULK or INTERRUPT transfer
 215         if request['type'] in (None, 'BULK IN') and self.transaction_type == 'IN':
 216             request['type'] = 'BULK IN'
 217             if len(request['data']) == 0 and len(self.transaction_data) > 0:
 218                 request['ss_data'] = self.ss_transaction
 219             request['data'] += self.transaction_data
 220             self.handle_request(request_started, request_end)
 221         elif request['type'] in (None, 'BULK OUT') and self.transaction_type == 'OUT':
 222             request['type'] = 'BULK OUT'
 223             if self.handshake == 'ACK':
 224                 request['data'] += self.transaction_data
 225             self.handle_request(request_started, request_end)
 226
 227         # CONTROL, SETUP stage
 228         elif request['type'] is None and self.transaction_type == 'SETUP':
 229             request['setup_data'] = self.transaction_data
 230             request['wLength'] = struct.unpack('<H',
 231                 bytes(self.transaction_data[6:8]))[0]
 232             if self.transaction_data[0] & 0x80:
 233                 request['type'] = 'SETUP IN'
 234                 self.handle_request(1, 0)
 235             else:
 236                 request['type'] = 'SETUP OUT'
 237                 self.handle_request(request['wLength'] == 0, 0)
 238
 239         # CONTROL, DATA stage
 240         elif request['type'] == 'SETUP IN' and self.transaction_type == 'IN':
 241             request['data'] += self.transaction_data
 242
 243         elif request['type'] == 'SETUP OUT' and self.transaction_type == 'OUT':
 244             if self.handshake == 'ACK':
 245                 request['data'] += self.transaction_data
 246             if request['wLength'] == len(request['data']):
 247                 self.handle_request(1, 0)
 248
 249         # CONTROL, STATUS stage
 250         elif request['type'] == 'SETUP IN' and self.transaction_type == 'OUT':
 251             self.handle_request(0, request_end)
 252
 253         elif request['type'] == 'SETUP OUT' and self.transaction_type == 'IN':
 254             self.handle_request(0, request_end)
 255
 256         else:
 257             return
 258
 259         return
 260
 261     def ts_from_samplenum(self, sample):
 262         ts = float(sample) * self.secs_per_sample
 263         return (int(ts), int((ts % 1.0) * 1e6))
 264
 265     def write_pcap_header(self):
 266         if not self.wrote_pcap_header:
 267             self.put(0, 0, self.out_binary, [0, self.pcap_global_header()])
 268             self.wrote_pcap_header = True
 269
 270     def request_summary(self, request):
 271         s = '['
 272         if request['type'] in ('SETUP IN', 'SETUP OUT'):
 273             for b in request['setup_data']:
 274                 s += ' %02X' % b
 275             s += ' ]['
 276         for b in request['data']:
 277             s += ' %02X' % b
 278         s += ' ] : %s' % request['handshake']
 279         return s
 280
 281     def handle_request(self, request_start, request_end):
 282         if request_start != 1 and request_end != 1:
 283             return
 284         self.write_pcap_header()
 285         ep = self.transaction_ep
 286         addr = self.transaction_addr
 287         request = self.request[(addr, ep)]
 288
 289         ss, es, ss_data = request['ss'], request['es'], request['ss_data']
 290         if self.in_request_start == 'submit':
 291             ss_data = ss
 292
 293         if request_start == 1:
 294             # Issue PCAP 'SUBMIT' packet.
 295             ts = self.ts_from_samplenum(ss)
 296             pkt = pcap_usb_pkt(request, ts, True)
 297             self.putb(ss, [0, pkt.record_header()])
 298             self.putb(ss, [0, pkt.packet()])
 299
 300         if request_end == 1:
 301             # Write annotation.
 302             summary = self.request_summary(request)
 303             if request['type'] == 'SETUP IN':
 304                 self.putr(ss, es, [0, ['SETUP in: %s' % summary]])
 305             elif request['type'] == 'SETUP OUT':
 306                 self.putr(ss, es, [1, ['SETUP out: %s' % summary]])
 307             elif request['type'] == 'BULK IN':
 308                 self.putr(ss_data, es, [2, ['BULK in: %s' % summary]])
 309             elif request['type'] == 'BULK OUT':
 310                 self.putr(ss, es, [3, ['BULK out: %s' % summary]])
 311
 312             # Issue PCAP 'COMPLETE' packet.
 313             ts = self.ts_from_samplenum(es)
 314             pkt = pcap_usb_pkt(request, ts, False)
 315             self.putb(ss, [0, pkt.record_header()])
 316             self.putb(ss, [0, pkt.packet()])
 317             del self.request[(addr, ep)]
 318
 319     def decode(self, ss, es, data):
 320         if not self.samplerate:
 321             raise SamplerateError('Cannot decode without samplerate.')
 322         ptype, pdata = data
 323
 324         # We only care about certain packet types for now.
 325         if ptype not in ('PACKET'):
 326             return
 327
 328         pcategory, pname, pinfo = pdata
 329
 330         if pcategory == 'TOKEN':
 331             if pname == 'SOF':
 332                 return
 333             if self.transaction_state == 'TOKEN RECEIVED':
 334                 transaction_timeout = self.es_transaction
 335                 # Token length is 35 bits, timeout is 16..18 bit times
 336                 # (USB 2.0 7.1.19.1).
 337                 transaction_timeout += int((self.es_transaction - self.ss_transaction) / 2)
 338                 if ss > transaction_timeout:
 339                     self.es_transaction = transaction_timeout
 340                     self.handshake = 'timeout'
 341                     self.handle_transfer()
 342                     self.transaction_state = 'IDLE'
 343
 344             if self.transaction_state != 'IDLE':
 345                 self.putr(ss, es, [4, ['ERR: received %s token in state %s' %
 346                     (pname, self.transaction_state)]])
 347                 return
 348
 349             sync, pid, addr, ep, crc5 = pinfo
 350             self.transaction_data = []
 351             self.ss_transaction = ss
 352             self.es_transaction = es
 353             self.transaction_state = 'TOKEN RECEIVED'
 354             self.transaction_ep = ep
 355             if ep > 0 and pname == 'IN':
 356                 self.transaction_ep = ep + 0x80
 357             self.transaction_addr = addr
 358             self.transaction_type = pname # IN OUT SETUP
 359
 360         elif pcategory == 'DATA':
 361             if self.transaction_state != 'TOKEN RECEIVED':
 362                 self.putr(ss, es, [4, ['ERR: received %s token in state %s' %
 363                     (pname, self.transaction_state)]])
 364                 return
 365
 366             self.transaction_data = pinfo[2]
 367             self.transaction_state = 'DATA RECEIVED'
 368
 369         elif pcategory == 'HANDSHAKE':
 370             if self.transaction_state not in ('TOKEN RECEIVED', 'DATA RECEIVED'):
 371                 self.putr(ss, es, [4, ['ERR: received %s token in state %s' %
 372                     (pname, self.transaction_state)]])
 373                 return
 374
 375             self.handshake = pname
 376             self.transaction_state = 'IDLE'
 377             self.es_transaction = es
 378             self.handle_transfer()
 379
 380         elif pname == 'PRE':
 381             return
 382
 383         else:
 384             self.putr(ss, es, [4, ['ERR: received unhandled %s token in state %s' %
 385                 (pname, self.transaction_state)]])
 386             return