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authorStefan Brüns <stefan.bruens@rwth-aachen.de>2015-10-04 00:43:38 +0200
committerUwe Hermann <uwe@hermann-uwe.de>2015-10-06 18:13:15 +0200
commitbd0e7d2e71e7a05b2bb0686a86a75b8fcb92fd54 (patch)
tree6f2aefd769730aaa190cd137ee3761ef90c17b55 /decoders/usb_request
parent91a19cb31778ccb6db79c4d4d75d993d974ebae0 (diff)
downloadlibsigrokdecode-bd0e7d2e71e7a05b2bb0686a86a75b8fcb92fd54.tar.gz
libsigrokdecode-bd0e7d2e71e7a05b2bb0686a86a75b8fcb92fd54.zip
usb_request: USB transaction decoder and PCAP generator
The new decoder stacks on top of the usb_packet PD. It adds one new annotation row, and is able to save the decoded data as PCAP trace. It has been successfully tested against all traces in sigrok-dumps and some more traces.
Diffstat (limited to 'decoders/usb_request')
-rw-r--r--decoders/usb_request/__init__.py50
-rw-r--r--decoders/usb_request/pd.py345
2 files changed, 395 insertions, 0 deletions
diff --git a/decoders/usb_request/__init__.py b/decoders/usb_request/__init__.py
new file mode 100644
index 0000000..7a156ff
--- /dev/null
+++ b/decoders/usb_request/__init__.py
@@ -0,0 +1,50 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2015 Stefan Brüns <stefan.bruens@rwth-aachen.de>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+##
+
+'''
+This decoder stacks on top of the 'usb_packet' PD and decodes the USB
+(low-speed and full-speed) transactions.
+
+Transactions and requests are tracked per device address and endpoint.
+
+Tracking of CONTROL requests is quite accurate, as these always start with
+a SETUP token and are completed by an IN or OUT transaction, the status
+packet. All transactions during the DATA stage are combined.
+
+For BULK and INTERRUPT requests, each transaction starts with an IN or OUT
+request, and is considered completed after the first transaction containing
+data has been ACKed. Normally a request is only completed after a short or
+zero length packet, but this would require knowledge about the max packet
+size of an endpoint.
+
+All INTERRUPT requests are treated as BULK requests, as on the link layer
+both are identical.
+
+The PCAP binary output contains 'SUBMIT' and 'COMPLETE' records. For
+CONTROL request, the SUBMIT contains the SETUP request, the data is
+either contained in the SUBMIT (Host-to-Device) or the COMPLETE
+(Device-to-Host) record.
+
+Details:
+https://en.wikipedia.org/wiki/USB
+http://www.usb.org/developers/docs/
+'''
+
+from .pd import Decoder
diff --git a/decoders/usb_request/pd.py b/decoders/usb_request/pd.py
new file mode 100644
index 0000000..060929b
--- /dev/null
+++ b/decoders/usb_request/pd.py
@@ -0,0 +1,345 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2015 Stefan Brüns <stefan.bruens@rwth-aachen.de>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+##
+
+import sigrokdecode as srd
+import struct
+
+class SamplerateError(Exception):
+ pass
+
+class pcap_usb_pkt():
+ # Linux usbmon format, see Documentation/usb/usbmon.txt
+ h = b'\x00\x00\x00\x00' # ID part 1
+ h += b'\x00\x00\x00\x00' # ID part 2
+ h += b'C' # 'S'ubmit / 'C'omplete / 'E'rror
+ h += b'\x03' # ISO (0), Intr, Control, Bulk (3)
+ h += b'\x00' # Endpoint
+ h += b'\x00' # Device address
+ h += b'\x00\x00' # Bus number
+ h += b'-' # Setup tag - 0: Setup present, '-' otherwise
+ h += b'<' # Data tag - '<' no data, 0 otherwise
+ # Timestamp
+ h += b'\x00\x00\x00\x00' # TS seconds part 1
+ h += b'\x00\x00\x00\x00' # TS seconds part 2
+ h += b'\x00\x00\x00\x00' # TS useconds
+ #
+ h += b'\x00\x00\x00\x00' # Status 0: OK
+ h += b'\x00\x00\x00\x00' # URB length
+ h += b'\x00\x00\x00\x00' # Data length
+ # Setup packet data, valid if setup tag == 0
+ h += b'\x00' # bmRequestType
+ h += b'\x00' # bRequest
+ h += b'\x00\x00' # wValue
+ h += b'\x00\x00' # wIndex
+ h += b'\x00\x00' # wLength
+ #
+ h += b'\x00\x00\x00\x00' # ISO/interrupt interval
+ h += b'\x00\x00\x00\x00' # ISO start frame
+ h += b'\x00\x00\x00\x00' # URB flags
+ h += b'\x00\x00\x00\x00' # Number of ISO descriptors
+
+ def __init__(self, req, ts, is_submit):
+ self.header = bytearray(pcap_usb_pkt.h)
+ self.data = b''
+ self.set_urbid(req['id'])
+ self.set_urbtype('S' if is_submit else 'C')
+ self.set_timestamp(ts)
+ self.set_addr_ep(req['addr'], req['ep'])
+ if req['type'] in ('SETUP IN', 'SETUP OUT'):
+ self.set_transfertype(2) # Control
+ self.set_setup(req['setup_data'])
+ if req['type'] in ('BULK IN'):
+ self.set_addr_ep(req['addr'], 0x80 | req['ep'])
+ self.set_data(req['data'])
+
+ def set_urbid(self, urbid):
+ self.header[4:8] = struct.pack('>I', urbid)
+
+ def set_urbtype(self, urbtype):
+ self.header[8] = ord(urbtype)
+
+ def set_transfertype(self, transfertype):
+ self.header[9] = transfertype
+
+ def set_addr_ep(self, addr, ep):
+ self.header[11] = addr
+ self.header[10] = ep
+
+ def set_timestamp(self, ts):
+ self.timestamp = ts
+ self.header[20:24] = struct.pack('>I', ts[0]) # seconds
+ self.header[24:28] = struct.pack('>I', ts[1]) # microseconds
+
+ def set_data(self, data):
+ self.data = data
+ self.header[15] = 0
+ self.header[36:40] = struct.pack('>I', len(data))
+
+ def set_setup(self, data):
+ self.header[14] = 0
+ self.header[40:48] = data
+
+ def packet(self):
+ return bytes(self.header) + bytes(self.data)
+
+ def record_header(self):
+ # See https://wiki.wireshark.org/Development/LibpcapFileFormat.
+ (secs, usecs) = self.timestamp
+ h = struct.pack('>I', secs) # TS seconds
+ h += struct.pack('>I', usecs) # TS microseconds
+ # No truncation, so both lengths are the same.
+ h += struct.pack('>I', len(self)) # Captured len (usb hdr + data)
+ h += struct.pack('>I', len(self)) # Original len
+ return h
+
+ def __len__(self):
+ return 64 + len(self.data)
+
+class Decoder(srd.Decoder):
+ api_version = 2
+ id = 'usb_request'
+ name = 'USB request'
+ longname = 'Universal Serial Bus (LS/FS) transaction/request'
+ desc = 'USB (low-speed and full-speed) transaction/request protocol.'
+ license = 'gplv2+'
+ inputs = ['usb_packet']
+ outputs = ['usb_request']
+ annotations = (
+ ('request-setup-read', 'Setup: Device-to-host'),
+ ('request-setup-write', 'Setup: Host-to-device'),
+ ('request-bulk-read', 'Bulk: Device-to-host'),
+ ('request-bulk-write', 'Bulk: Host-to-device'),
+ ('errors', 'Unexpected packets'),
+ )
+ annotation_rows = (
+ ('request', 'USB requests', tuple(range(4))),
+ ('errors', 'Errors', (4,)),
+ )
+ binary = (
+ ('pcap', 'PCAP format'),
+ )
+
+ def __init__(self):
+ self.samplerate = 8e6 # None
+ self.secs_per_sample = float(1) / float(self.samplerate)
+ self.request = {}
+ self.request_id = 0
+ self.transaction_state = 'IDLE'
+ self.transaction_ss = None
+ self.transaction_es = None
+ self.transaction_ep = None
+ self.transaction_addr = None
+ self.wrote_pcap_header = False
+
+ def putr(self, ss, es, data):
+ self.put(ss, es, self.out_ann, data)
+
+ def putb(self, ts, data):
+ self.put(ts, ts, self.out_bin, data)
+
+ def pcap_global_header(self):
+ # See https://wiki.wireshark.org/Development/LibpcapFileFormat.
+ h = b'\xa1\xb2\xc3\xd4' # Magic, indicate microsecond ts resolution
+ h += b'\x00\x02' # Major version 2
+ h += b'\x00\x04' # Minor version 4
+ h += b'\x00\x00\x00\x00' # Correction vs. UTC, seconds
+ h += b'\x00\x00\x00\x00' # Timestamp accuracy
+ h += b'\xff\xff\xff\xff' # Max packet len
+ # LINKTYPE_USB_LINUX_MMAPPED 220
+ # Linux usbmon format, see Documentation/usb/usbmon.txt.
+ h += b'\x00\x00\x00\xdc' # Link layer
+ return h
+
+ def metadata(self, key, value):
+ if key == srd.SRD_CONF_SAMPLERATE:
+ self.samplerate = value
+ self.secs_per_sample = float(1) / float(self.samplerate)
+
+ def start(self):
+ self.out_bin = self.register(srd.OUTPUT_BINARY)
+ self.out_ann = self.register(srd.OUTPUT_ANN)
+
+ def handle_transfer(self):
+ request_started = 0
+ request_end = self.handshake in ('ACK', 'STALL')
+ ep = self.transaction_ep
+ addr = self.transaction_addr
+ if not (addr, ep) in self.request:
+ self.request[(addr, ep)] = {'setup_data': [], 'data': [],
+ 'type': None, 'ss': self.transaction_ss, 'es': None,
+ 'id': self.request_id, 'addr': addr, 'ep': ep}
+ self.request_id += 1
+ request_started = 1
+ request = self.request[(addr,ep)]
+
+ # BULK or INTERRUPT transfer
+ if request['type'] in (None, 'BULK IN') and self.transaction_type == 'IN':
+ request['type'] = 'BULK IN'
+ request['data'] += self.transaction_data
+ request['es'] = self.transaction_es
+ self.handle_request(request_started, request_end)
+ elif request['type'] in (None, 'BULK OUT') and self.transaction_type == 'OUT':
+ request['type'] = 'BULK OUT'
+ request['data'] += self.transaction_data
+ request['es'] = self.transaction_es
+ self.handle_request(request_started, request_end)
+
+ # CONTROL, SETUP stage
+ elif request['type'] == None and self.transaction_type == 'SETUP':
+ request['setup_data'] = self.transaction_data
+ request['wLength'] = struct.unpack('<H',
+ bytes(self.transaction_data[6:8]))[0]
+ if self.transaction_data[0] & 0x80:
+ request['type'] = 'SETUP IN'
+ self.handle_request(1, 0)
+ else:
+ request['type'] = 'SETUP OUT'
+ self.handle_request(request['wLength'] == 0, 0)
+
+ # CONTROL, DATA stage
+ elif request['type'] == 'SETUP IN' and self.transaction_type == 'IN':
+ request['data'] += self.transaction_data
+
+ elif request['type'] == 'SETUP OUT' and self.transaction_type == 'OUT':
+ request['data'] += self.transaction_data
+ if request['wLength'] == len(request['data']):
+ self.handle_request(1, 0)
+
+ # CONTROL, STATUS stage
+ elif request['type'] == 'SETUP IN' and self.transaction_type == 'OUT':
+ request['es'] = self.transaction_es
+ self.handle_request(0, request_end)
+
+ elif request['type'] == 'SETUP OUT' and self.transaction_type == 'IN':
+ request['es'] = self.transaction_es
+ self.handle_request(0, request_end)
+
+ else:
+ return
+
+ return
+
+ def ts_from_samplenum(self, sample):
+ ts = float(sample) * self.secs_per_sample
+ return (int(ts), int((ts % 1.0) * 1e6))
+
+ def write_pcap_header(self):
+ if not self.wrote_pcap_header:
+ self.put(0, 0, self.out_bin, (0, self.pcap_global_header()))
+ self.wrote_pcap_header = True
+
+ def request_summary(self, request):
+ s = '['
+ if request['type'] in ('SETUP IN', 'SETUP OUT'):
+ for b in request['setup_data']:
+ s += ' %02X' % b
+ s += ' ]['
+ for b in request['data']:
+ s += ' %02X' % b
+ s += ' ] : %s' % self.handshake
+ return s
+
+ def handle_request(self, request_start, request_end):
+ if request_start != 1 and request_end != 1:
+ return
+ self.write_pcap_header()
+ ep = self.transaction_ep
+ addr = self.transaction_addr
+ request = self.request[(addr, ep)]
+
+ ss, es = request['ss'], request['es']
+
+ if request_start == 1:
+ # Issue PCAP 'SUBMIT' packet.
+ ts = self.ts_from_samplenum(ss)
+ pkt = pcap_usb_pkt(request, ts, True)
+ self.putb(ss, (0, pkt.record_header()))
+ self.putb(ss, (0, pkt.packet()))
+
+ if request_end == 1:
+ # Write annotation.
+ summary = self.request_summary(request)
+ if request['type'] == 'SETUP IN':
+ self.putr(ss, es, [0, ['SETUP in: %s' % summary]])
+ elif request['type'] == 'SETUP OUT':
+ self.putr(ss, es, [1, ['SETUP out: %s' % summary]])
+ elif request['type'] == 'BULK IN':
+ self.putr(ss, es, [2, ['BULK in: %s' % summary]])
+ elif request['type'] == 'BULK OUT':
+ self.putr(ss, es, [3, ['BULK out: %s' % summary]])
+
+ # Issue PCAP 'COMPLETE' packet.
+ ts = self.ts_from_samplenum(es)
+ pkt = pcap_usb_pkt(request, ts, False)
+ self.putb(ss, (0, pkt.record_header()))
+ self.putb(ss, (0, pkt.packet()))
+ del self.request[(addr, ep)]
+
+ def decode(self, ss, es, data):
+ if not self.samplerate:
+ raise SamplerateError('Cannot decode without samplerate.')
+ ptype, pdata = data
+
+ # We only care about certain packet types for now.
+ if ptype not in ('PACKET'):
+ return
+
+ pcategory, pname, pinfo = pdata
+
+ if pcategory == 'TOKEN':
+ if pname == 'SOF':
+ return
+ if self.transaction_state != 'IDLE':
+ self.putr(ss, es, [4, ['ERR: received %s token in state %s' %
+ (pname, self.transaction_state)]])
+ return
+
+ sync, pid, addr, ep, crc5 = pinfo
+ self.transaction_data = []
+ self.transaction_ss = ss
+ self.transaction_state = 'TOKEN RECEIVED'
+ self.transaction_ep = ep
+ self.transaction_addr = addr
+ self.transaction_type = pname # IN OUT SETUP
+
+ elif pcategory == 'DATA':
+ if self.transaction_state != 'TOKEN RECEIVED':
+ self.putr(ss, es, [4, ['ERR: received %s token in state %s' %
+ (pname, self.transaction_state)]])
+ return
+
+ self.transaction_data = pinfo[2]
+ self.transaction_state = 'DATA RECEIVED'
+
+ elif pcategory == 'HANDSHAKE':
+ if self.transaction_state not in ('TOKEN RECEIVED', 'DATA RECEIVED'):
+ self.putr(ss, es, [4, ['ERR: received %s token in state %s' %
+ (pname, self.transaction_state)]])
+ return
+
+ self.handshake = pname
+ self.transaction_state = 'IDLE'
+ self.transaction_es = es
+ self.handle_transfer()
+
+ else:
+ self.putr(ss, es, [4, ['ERR: received unhandled %s token in state %s' %
+ (pname, self.transaction_state)]])
+ return