FaxPcap Class Reference

Inheritance diagram for FaxPcap:

Collaboration diagram for FaxPcap:

Public Member Functions
def	__init__ (self, outfile)
def	add (self, ifp)

Data Fields
	date
	outfile
	prev_data
	seqno
	udpseqno

Static Public Attributes
	PCAP_PREAMBLE

Detailed Description

Definition at line 56 of file spandspflow2pcap.py.

Constructor & Destructor Documentation

__init__()

def __init__	(		self,
			outfile
	)

Definition at line 62 of file spandspflow2pcap.py.

    def __init__(self, outfile):
        self.outfile = outfile
        self.date = None
        self.seqno = None
        self.udpseqno = 128
        self.prev_data = None
 
        # Only do this if at pos 0?
 

Member Function Documentation

add()

def add	(		self,
			ifp
	)

Add the IFP packet.

T.38 basic format of UDPTL payload section with redundancy:

UDPTL_SEQNO
- 2 sequence number (big endian)
UDPTL_PRIMARY_PAYLOAD (T30?)
- 1 subpacket length (excluding this byte)
- 1 type of message (e.g. 0xd0 for data(?))
- 1 items in data field (e.g. 0x01)
- 2 length of data (big endian)
- N data
RECOVERY (optional)
- 2 count of previous seqno packets (big endian)
- N UDPTL_PRIMARY_PAYLOAD of (seqno-1)
- N UDPTL_PRIMARY_PAYLOAD of (seqno-2)
- ...

Definition at line 71 of file spandspflow2pcap.py.

    def add(self, ifp):
        """
        Add the IFP packet.
 
        T.38 basic format of UDPTL payload section with redundancy:
 
        UDPTL_SEQNO
        - 2 sequence number (big endian)
        UDPTL_PRIMARY_PAYLOAD (T30?)
        - 1 subpacket length (excluding this byte)
        - 1 type of message (e.g. 0xd0 for data(?))
        - 1 items in data field (e.g. 0x01)
        - 2 length of data (big endian)
        - N data
        RECOVERY (optional)
        - 2 count of previous seqno packets (big endian)
        - N UDPTL_PRIMARY_PAYLOAD of (seqno-1)
        - N UDPTL_PRIMARY_PAYLOAD of (seqno-2)
        - ...
        """
        # First packet?
        if self.seqno is None:
            # Add preamble.
            self._add_preamble()
            # Start a second late (optional).
            self._add_garbage(ifp.date)
 
            # Set sequence, and fill with missing leading zeroes.
            self.seqno = 0
            for i in range(ifp.seqno):
                self.add(IFP(date=ifp.date, seqno=i, data=bytearray([0])))
 
        # Auto-increasing dates
        if self.date is None or ifp.date > self.date:
            self.date = ifp.date
        elif ifp.date < self.date.replace(microsecond=0):
            assert False, 'More packets than expected in 1s? {!r}/{!r}'.format(
                ifp.date, self.date)
        else:
            self.date += timedelta(microseconds=9000)
 
        # Add packet.
        self.seqno = ifp.seqno
        try:
            self.outfile.write(self._make_packet(ifp.data))
        except SkipPacket:
            pass
 

References FaxPcap._add_garbage(), FaxPcap._add_preamble(), FaxPcap._make_packet(), FaxPcap.add(), FaxPcap.date, logmsg.date, spandspflow2pcap.IFP, len(), FaxPcap.outfile, FaxPcap.PCAP_PREAMBLE, FaxPcap.prev_data, replace(), FaxPcap.seqno, ast_bridge_hook_timer_parms.seqno, ast_frame.seqno, rtp_transport_wide_cc_packet_statistics.seqno, ast_rtp.seqno, multicast_rtp.seqno, and FaxPcap.udpseqno.

Referenced by FaxPcap.add().

Field Documentation

date

date

Definition at line 64 of file spandspflow2pcap.py.

Referenced by FaxPcap.add().

outfile

outfile

Definition at line 63 of file spandspflow2pcap.py.

Referenced by FaxPcap.add().

PCAP_PREAMBLE

PCAP_PREAMBLE

static

Initial value:

=  n2b(
        'd4 c3 b2 a1 02 00 04 00'
        '00 00 00 00 00 00 00 00'
        'ff ff 00 00 71 00 00 00')

Definition at line 57 of file spandspflow2pcap.py.

Referenced by FaxPcap.add().

prev_data

prev_data

Definition at line 67 of file spandspflow2pcap.py.

Referenced by FaxPcap.add().

seqno

seqno

Definition at line 65 of file spandspflow2pcap.py.

Referenced by FaxPcap.add().

udpseqno

udpseqno

Definition at line 66 of file spandspflow2pcap.py.

Referenced by FaxPcap.add().

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The documentation for this class was generated from the following file:

• spandspflow2pcap.py