diff --git a/scapy/utils.py b/scapy/utils.py
index 40ce9a4b47a1b78247f8eab23ba6281e683a46e8..c3febf59e2bb97d9f1d61172b8e900cab20c17c8 100644
--- a/scapy/utils.py
+++ b/scapy/utils.py
@@ -548,49 +548,77 @@ def rdpcap(filename, count=-1):
count: read only <count> packets
"""
- try:
- return _rdpcap(filename, count=count)
- except Scapy_Exception:
- pass
- try:
- return _rdpcapng(filename, count=count)
- except Scapy_Exception:
- raise Scapy_Exception("Not a valid pcap or pcapng file")
-
+ with PcapReader(filename) as fdesc:
+ return fdesc.read_all(count=count)
-def _rdpcap(filename, count=-1):
- """Read a pcap file and return a packet list
-count: read only <count> packets
+class PcapReader_metaclass(type):
+ """Metaclass for (Raw)Pcap(Ng)Readers"""
- """
- with PcapReader(filename) as fdesc:
- return fdesc.read_all(count=count)
+ def __new__(cls, name, bases, dct):
+ """The `alternative` class attribute is declared in the PcapNg
+ variant, and set here to the Pcap variant.
-def _rdpcapng(filename, count=-1):
- """Read a pcapng file and return a packet list
+ """
+ newcls = super(PcapReader_metaclass, cls).__new__(cls, name, bases, dct)
+ if 'alternative' in dct:
+ dct['alternative'].alternative = newcls
+ return newcls
-count: read only <count> packets
+ def __call__(cls, filename):
+ """Creates a cls instance, use the `alternative` if that
+ fails.
- """
- with PcapNgReader(filename) as fdesc:
- return fdesc.read_all(count=count)
+ """
+ i = cls.__new__(cls, cls.__name__, cls.__bases__, cls.__dict__)
+ filename, fdesc, magic = cls.open(filename)
+ try:
+ i.__init__(filename, fdesc, magic)
+ except Scapy_Exception:
+ if "alternative" in cls.__dict__:
+ cls = cls.__dict__["alternative"]
+ i = cls.__new__(cls, cls.__name__, cls.__bases__, cls.__dict__)
+ try:
+ i.__init__(filename, fdesc, magic)
+ except Scapy_Exception:
+ try:
+ self.f.seek(-4, 1)
+ except:
+ pass
+ raise Scapy_Exception("Not a supported capture file")
+
+ return i
+
+ @staticmethod
+ def open(filename):
+ """Open (if necessary) filename, and read the magic."""
+ if isinstance(filename, basestring):
+ try:
+ fdesc = gzip.open(filename,"rb")
+ magic = fdesc.read(4)
+ except IOError:
+ fdesc = open(filename,"rb")
+ magic = fdesc.read(4)
+ else:
+ fdesc = filename
+ filename = (fdesc.name
+ if hasattr(fdesc, "name") else
+ "No name")
+ magic = fdesc.read(4)
+ return filename, fdesc, magic
class RawPcapReader:
"""A stateful pcap reader. Each packet is returned as a string"""
-
- def __init__(self, filename):
- magic = self.open(filename)
+ __metaclass__ = PcapReader_metaclass
+ def __init__(self, filename, fdesc, magic):
+ self.filename = filename
+ self.f = fdesc
if magic == "\xa1\xb2\xc3\xd4": #big endian
self.endian = ">"
elif magic == "\xd4\xc3\xb2\xa1": #little endian
self.endian = "<"
else:
- try:
- self.f.seek(-4, 1)
- except:
- pass
raise Scapy_Exception(
"Not a pcap capture file (bad magic: %r)" % magic
)
@@ -602,23 +630,6 @@ class RawPcapReader:
)
self.linktype = linktype
- def open(self, filename):
- """Open (if necessary) filename"""
- if isinstance(filename, basestring):
- self.filename = filename
- try:
- self.f = gzip.open(filename,"rb")
- return self.f.read(4)
- except IOError:
- self.f = open(filename,"rb")
- return self.f.read(4)
- else:
- self.f = filename
- self.filename = (filename.name
- if hasattr(filename, "name") else
- "No name")
- return self.f.read(4)
-
def __iter__(self):
return self
@@ -684,8 +695,8 @@ class RawPcapReader:
class PcapReader(RawPcapReader):
- def __init__(self, filename):
- RawPcapReader.__init__(self, filename)
+ def __init__(self, filename, fdesc, magic):
+ RawPcapReader.__init__(self, filename, fdesc, magic)
try:
self.LLcls = conf.l2types[self.linktype]
except KeyError:
@@ -721,19 +732,18 @@ class RawPcapNgReader(RawPcapReader):
"""
- def __init__(self, filename):
+ alternative = RawPcapReader
+
+ def __init__(self, filename, fdesc, magic):
+ self.filename = filename
+ self.f = fdesc
# A list of (linktype, snaplen); will be populated by IDBs.
self.interfaces = []
self.blocktypes = {
1: self.read_block_idb,
6: self.read_block_epb,
}
- magic = self.open(filename)
if magic != "\x0a\x0d\x0d\x0a": # PcapNg:
- try:
- self.f.seek(-4, 1)
- except:
- pass
raise Scapy_Exception(
"Not a pcapng capture file (bad magic: %r)" % magic
)
@@ -786,8 +796,12 @@ class RawPcapNgReader(RawPcapReader):
class PcapNgReader(RawPcapNgReader):
- def __init__(self, filename):
- RawPcapNgReader.__init__(self, filename)
+
+ alternative = PcapReader
+
+ def __init__(self, filename, fdesc, magic):
+ RawPcapNgReader.__init__(self, filename, fdesc, magic)
+
def read_packet(self, size=MTU):
rp = RawPcapNgReader.read_packet(self, size=size)
if rp is None:
diff --git a/test/regression.uts b/test/regression.uts
index 3cf4b298e4a57fda22d9f9297ac961509f19bedf..fd2569158aab4b6d7e6c2843baba25e2d3457cb2 100644
--- a/test/regression.uts
+++ b/test/regression.uts
@@ -4300,10 +4300,10 @@ pcapfile = cStringIO.StringIO('\xd4\xc3\xb2\xa1\x02\x00\x04\x00\x00\x00\x00\x00\
pcapngfile = cStringIO.StringIO('\n\r\r\n\\\x00\x00\x00M<+\x1a\x01\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\x01\x00,\x00File created by merging: \nFile1: test.pcap \n\x04\x00\x08\x00mergecap\x00\x00\x00\x00\\\x00\x00\x00\x01\x00\x00\x00\\\x00\x00\x00e\x00\x00\x00\xff\xff\x00\x00\x02\x006\x00Unknown/not available in original file format(libpcap)\x00\x00\t\x00\x01\x00\x06\x00\x00\x00\x00\x00\x00\x00\\\x00\x00\x00\x06\x00\x00\x00H\x00\x00\x00\x00\x00\x00\x00\x8d*\x05\x00/\xfc[\xcd(\x00\x00\x00(\x00\x00\x00E\x00\x00(\x00\x01\x00\x00@\x06|\xcd\x7f\x00\x00\x01\x7f\x00\x00\x01\x00\x14\x00P\x00\x00\x00\x00\x00\x00\x00\x00P\x02 \x00\x91|\x00\x00H\x00\x00\x00\x06\x00\x00\x00<\x00\x00\x00\x00\x00\x00\x00\x8d*\x05\x00\x1f\xff[\xcd\x1c\x00\x00\x00\x1c\x00\x00\x00E\x00\x00\x1c\x00\x01\x00\x00@\x11|\xce\x7f\x00\x00\x01\x7f\x00\x00\x01\x005\x005\x00\x08\x01r<\x00\x00\x00\x06\x00\x00\x00<\x00\x00\x00\x00\x00\x00\x00\x8d*\x05\x00\xb9\x02\\\xcd\x1c\x00\x00\x00\x1c\x00\x00\x00E\x00\x00\x1c\x00\x01\x00\x00@\x01|\xde\x7f\x00\x00\x01\x7f\x00\x00\x01\x08\x00\xf7\xff\x00\x00\x00\x00<\x00\x00\x00')
= Read a pcap file
-pktpcap = utils._rdpcap(pcapfile)
+pktpcap = rdpcap(pcapfile)
= Read a pcapng file
-pktpcapng = utils._rdpcapng(pcapngfile)
+pktpcapng = rdpcap(pcapngfile)
= Check both packet lists are the same
assert list(pktpcap) == list(pktpcapng)