Merge pull request #1240 from karpierz/little_but_obvious_code_improvements_2

Scapy 2.4.0rc5-40: Little but obvious code improvements. [PR is ready for merge to the master]

Author: p-l-

scapy/arch/__init__.py

@@ -78,11 +78,8 @@ def get_if_addr6(iff):
     interface, in human readable form. If no global address is found,
     None is returned. 
     """
-    for x in in6_getifaddr():
-        if x[2] == iff and x[1] == IPV6_ADDR_GLOBAL:
-            return x[0]
-        
-    return None
+    return next((x[0] for x in in6_getifaddr()
+                 if x[2] == iff and x[1] == IPV6_ADDR_GLOBAL), None)
 
 def get_if_raw_addr6(iff):
     """

scapy/arch/windows/__init__.py

@@ -371,11 +371,13 @@ def _where(filename, dirs=None, env="PATH"):
     if glob(filename):
         return filename
     paths = [os.curdir] + os.environ[env].split(os.path.pathsep) + dirs
-    for path in paths:
-        for match in glob(os.path.join(path, filename)):
-            if match:
-                return os.path.normpath(match)
-    raise IOError("File not found: %s" % filename)
+    try:
+        return next(os.path.normpath(match)
+                    for path in paths
+                    for match in glob(os.path.join(path, filename))
+                    if match)
+    except StopIteration:
+        raise IOError("File not found: %s" % filename)
 
 def win_find_exe(filename, installsubdir=None, env="ProgramFiles"):
     """Find executable in current dir, system path or given ProgramFiles subdir"""
@@ -810,28 +812,31 @@ def dev_from_name(self, name):
         """Return the first pcap device name for a given Windows
         device name.
         """
-        for iface in six.itervalues(self):
-            if iface.name == name:
-                return iface
-        raise ValueError("Unknown network interface %r" % name)
+        try:
+            return next(iface for iface in six.itervalues(self)
+                        if iface.name == name)
+        except StopIteration:
+            raise ValueError("Unknown network interface %r" % name)
 
     def dev_from_pcapname(self, pcap_name):
         """Return Windows device name for given pcap device name."""
-        for iface in six.itervalues(self):
-            if iface.pcap_name == pcap_name:
-                return iface
-        raise ValueError("Unknown pypcap network interface %r" % pcap_name)
+        try:
+            return next(iface for iface in six.itervalues(self)
+                        if iface.pcap_name == pcap_name)
+        except StopIteration:
+            raise ValueError("Unknown pypcap network interface %r" % pcap_name)
 
     def dev_from_index(self, if_index):
         """Return interface name from interface index"""
-        for devname, iface in six.iteritems(self):
-            if iface.win_index == str(if_index):
-                return iface
-        if str(if_index) == "1":
-            # Test if the loopback interface is set up
-            if isinstance(scapy.consts.LOOPBACK_INTERFACE, NetworkInterface):
-                return scapy.consts.LOOPBACK_INTERFACE
-        raise ValueError("Unknown network interface index %r" % if_index)
+        try:
+            return next(iface for iface in six.itervalues(self)
+                        if iface.win_index == str(if_index))
+        except StopIteration:
+            if str(if_index) == "1":
+                # Test if the loopback interface is set up
+                if isinstance(scapy.consts.LOOPBACK_INTERFACE, NetworkInterface):
+                    return scapy.consts.LOOPBACK_INTERFACE
+            raise ValueError("Unknown network interface index %r" % if_index)
 
     def remove_invalid_ifaces(self):
         """Remove all invalid interfaces"""
@@ -1150,9 +1155,8 @@ def _get_valid_guid():
     if scapy.consts.LOOPBACK_INTERFACE:
         return scapy.consts.LOOPBACK_INTERFACE.guid
     else:
-        for i in six.itervalues(IFACES):
-            if not i.is_invalid():
-                return i.guid
+        return next((i.guid for i in six.itervalues(IFACES)
+                     if not i.is_invalid()), None)
 
 def route_add_loopback(routes=None, ipv6=False, iflist=None):
     """Add a route to 127.0.0.1 and ::1 to simplify unit tests on Windows"""

scapy/asn1fields.py

@@ -279,10 +279,7 @@ def __init__(self, *seq, **kwargs):
         default = [field.default for field in seq]
         for kwarg in ["context", "implicit_tag",
                       "explicit_tag", "flexible_tag"]:
-            if kwarg in kwargs:
-                setattr(self, kwarg, kwargs[kwarg])
-            else:
-                setattr(self, kwarg, None)
+            setattr(self, kwarg, kwargs.get(kwarg))
         ASN1F_field.__init__(self, name, default, context=self.context,
                              implicit_tag=self.implicit_tag,
                              explicit_tag=self.explicit_tag,
@@ -292,10 +289,7 @@ def __init__(self, *seq, **kwargs):
     def __repr__(self):
         return "<%s%r>" % (self.__class__.__name__, self.seq)
     def is_empty(self, pkt):
-        for f in self.seq:
-            if not f.is_empty(pkt):
-                return False
-        return True
+        return all(f.is_empty(pkt) for f in self.seq)
     def get_fields_list(self):
         return reduce(lambda x,y: x+y.get_fields_list(), self.seq, [])
     def m2i(self, pkt, s):
@@ -441,10 +435,7 @@ def __init__(self, name, default, *args, **kwargs):
             raise ASN1_Error(err_msg)
         self.implicit_tag = None
         for kwarg in ["context", "explicit_tag"]:
-            if kwarg in kwargs:
-                setattr(self, kwarg, kwargs[kwarg])
-            else:
-                setattr(self, kwarg, None)
+            setattr(self, kwarg, kwargs.get(kwarg))
         ASN1F_field.__init__(self, name, None, context=self.context,
                              explicit_tag=self.explicit_tag)
         self.default = default
@@ -569,10 +560,7 @@ def m2i(self, pkt, s):
             raise BER_Decoding_Error("unexpected remainder", remaining=s)
         return p, remain
     def i2m(self, pkt, x):
-        if x is None:
-            s = b""
-        else:
-            s = raw(x)
+        s = b"" if x is None else raw(x)
         s = b"".join(binrepr(orb(x)).zfill(8).encode("utf8") for x in s)
         return ASN1F_BIT_STRING.i2m(self, pkt, s)
 
@@ -587,11 +575,8 @@ def __init__(self, name, default, mapping, context=None,
                                   explicit_tag=explicit_tag)
     def get_flags(self, pkt):
         fbytes = getattr(pkt, self.name).val
-        flags = []
-        for i, positional in enumerate(fbytes):
-            if positional == '1' and i < len(self.mapping):
-                flags.append(self.mapping[i])
-        return flags
+        return [self.mapping[i] for i, positional in enumerate(fbytes)
+                if positional == '1' and i < len(self.mapping)]
     def i2repr(self, pkt, x):
         if x is not None:
             pretty_s = ", ".join(self.get_flags(pkt))

scapy/base_classes.py

@@ -7,7 +7,7 @@
 Generators and packet meta classes.
 """
 
-###############
+################
 ## Generators ##
 ################
 
@@ -24,7 +24,7 @@ def __iter__(self):
 
 def _get_values(value):
     """Generate a range object from (start, stop[, step]) tuples, or
-return value.
+    return value.
 
     """
     if (isinstance(value, tuple) and (2 <= len(value) <= 3) and \
@@ -197,10 +197,7 @@ def __new__(cls, name, bases, dct):
             for attr in cls.__slots__
         )
 
-        if hasattr(newcls, "aliastypes"):
-            newcls.aliastypes = [newcls] + newcls.aliastypes
-        else:
-            newcls.aliastypes = [newcls]
+        newcls.aliastypes = [newcls] + getattr(newcls, "aliastypes", [])
 
         if hasattr(newcls,"register_variant"):
             newcls.register_variant()

scapy/config.py

@@ -124,10 +124,9 @@ def __contains__(self, item):
         if isinstance(item, base_classes.Packet_metaclass):
             return item in self.layer2num
         return item in self.num2layer
+
     def get(self, item, default=None):
-        if item in self:
-            return self[item]
-        return default
+        return self[item] if item in self else default
 
     def __repr__(self):
         lst = []
@@ -147,22 +146,18 @@ def __repr__(self):
 
 
 class LayersList(list):
+
     def __repr__(self):
-        s=[]
-        for l in self:
-            s.append("%-20s: %s" % (l.__name__,l.name))
-        return "\n".join(s)
+        return "\n".join("%-20s: %s" % (l.__name__, l.name) for l in self)
+
     def register(self, layer):
         self.append(layer)
 
 class CommandsList(list):
     def __repr__(self):
         s=[]
         for l in sorted(self,key=lambda x:x.__name__):
-            if l.__doc__:
-                doc = l.__doc__.split("\n")[0]
-            else:
-                doc = "--"
+            doc = l.__doc__.split("\n")[0] if l.__doc__ else "--"
             s.append("%-20s: %s" % (l.__name__,doc))
         return "\n".join(s)
     def register(self, cmd):

scapy/contrib/diameter.py

@@ -353,7 +353,7 @@ def GuessAvpType(p, **kargs):
         vndCode = vnd and struct.unpack("!I", p[8:12])[0] or 0
         # Check if vendor and code defined and fetch the corresponding AVP
         # definition
-        if vndCode in AvpDefDict.keys():
+        if vndCode in AvpDefDict:
             AvpVndDict = AvpDefDict[vndCode]
             if avpCode in AvpVndDict:
                 # Unpack only the first 4 tupple items at this point
@@ -392,8 +392,8 @@ def AVP(avpId, **fields):
     classType = AVP_Unknown
     if isinstance(avpId, str):
         try:
-            for vnd in AvpDefDict.keys():
-                for code in AvpDefDict[vnd].keys():
+            for vnd in AvpDefDict:
+                for code in AvpDefDict[vnd]:
                     val = AvpDefDict[vnd][code]
                     if val[0][:len(
                             avpId)] == avpId:  # A prefix of the full name is considered valid
@@ -421,10 +421,10 @@ def AVP(avpId, **fields):
     # Set/override AVP code
     fields['avpCode'] = code
     # Set vendor if not already defined and relevant
-    if 'avpVnd' not in fields.keys() and vnd:
+    if 'avpVnd' not in fields and vnd:
         fields['avpVnd'] = vnd
     # Set flags if not already defined and possible ...
-    if 'avpFlags' not in fields.keys():
+    if 'avpFlags' not in fields:
         if val:
             fields['avpFlags'] = val[2]
         else:
@@ -4748,7 +4748,7 @@ def getCmdParams(cmd, request, **fields):
     # Fetch the parameters if cmd is found in dict
     if isinstance(cmd, int):
         drCode = cmd    # Enable to craft commands with non standard code
-        if cmd in DR_cmd_def.keys():
+        if cmd in DR_cmd_def:
             params = DR_cmd_def[drCode]
         else:
             params = ('Unknown', 'UK', {0: (128, 0)})
@@ -4775,7 +4775,7 @@ def getCmdParams(cmd, request, **fields):
     # The drCode is set/overriden in any case
     fields['drCode'] = drCode
     # Processing of drAppId
-    if 'drAppId' in fields.keys():
+    if 'drAppId' in fields:
         val = fields['drAppId']
         if isinstance(val, str):   # Translate into application Id code
             found = False
@@ -4799,7 +4799,7 @@ def getCmdParams(cmd, request, **fields):
     # Set the command name
     name = request and params[0] + '-Request' or params[0] + '-Answer'
     # Processing of flags (only if not provided manually)
-    if 'drFlags' not in fields.keys():
+    if 'drFlags' not in fields:
         if drAppId in params[2].keys():
             flags = params[2][drAppId]
             fields['drFlags'] = request and flags[0] or flags[1]

scapy/contrib/openflow3.py

@@ -600,7 +600,7 @@ def getfield(self, pkt, s):
             l = OXMPacketListField._get_oxm_length(remain) + 4
             # this could also be done by parsing oxm_fields (fixed lengths)
             if l <= 4 or len(remain) < l:
-            # no incoherent length
+                # no incoherent length
                 break
             current = remain[:l]
             remain = remain[l:]
@@ -997,9 +997,9 @@ def getfield(self, pkt, s):
         while remain and len(remain)>=4:
             l = ActionPacketListField._get_action_length(remain)
             if l < 8 or len(remain) < l:
-              # length should be at least 8 (non-zero, 64-bit aligned),
-              # and no incoherent length
-              break
+                # length should be at least 8 (non-zero, 64-bit aligned),
+                # and no incoherent length
+                break
             current = remain[:l]
             remain = remain[l:]
             p = self.m2i(pkt, current)
@@ -1214,8 +1214,8 @@ def getfield(self, pkt, s):
         while remain and len(remain) >= 4:
             l = ActionIDPacketListField._get_action_id_length(remain)
             if l < 4 or len(remain) < l:
-            # length is 4 (may be more for experimenter messages),
-            # and no incoherent length
+                # length is 4 (may be more for experimenter messages),
+                # and no incoherent length
                 break
             current = remain[:l]
             remain = remain[l:]
@@ -1317,8 +1317,8 @@ def getfield(self, pkt, s):
         while remain and len(remain) > 4:
             l = InstructionPacketListField._get_instruction_length(remain)
             if l < 8 or len(remain) < l:
-            # length should be at least 8 (non-zero, 64-bit aligned),
-            # and no incoherent length
+                # length should be at least 8 (non-zero, 64-bit aligned),
+                # and no incoherent length
                 break
             current = remain[:l]
             remain = remain[l:]
@@ -1392,8 +1392,8 @@ def getfield(self, pkt, s):
         while remain and len(remain) >= 4:
             l = InstructionIDPacketListField._get_instruction_id_length(remain)
             if l < 4 or len(remain) < l:
-            # length is 4 (may be more for experimenter messages),
-            # and no incoherent length
+                # length is 4 (may be more for experimenter messages),
+                # and no incoherent length
                 break
             current = remain[:l]
             remain = remain[l:]
@@ -3019,7 +3019,7 @@ def getfield(self, pkt, s):
             # add padding !
             lpad = l + (8 - l%8)%8
             if l < 4 or len(remain) < lpad:
-            # no zero length nor incoherent length
+                # no zero length nor incoherent length
                 break
             current = remain[:lpad]
             remain = remain[lpad:]

scapy/error.py

@@ -45,16 +45,8 @@ def filter(self, record):
             self.warning_table[caller] = (tm,nb)
         return 1    
 
-try:
-    from logging import NullHandler
-except ImportError:
-    # compat for python 2.6
-    from logging import Handler
-    class NullHandler(Handler):
-        def emit(self, record):
-            pass
 log_scapy = logging.getLogger("scapy")
-log_scapy.addHandler(NullHandler())
+log_scapy.addHandler(logging.NullHandler())
 log_runtime = logging.getLogger("scapy.runtime")          # logs at runtime
 log_runtime.addFilter(ScapyFreqFilter())
 log_interactive = logging.getLogger("scapy.interactive")  # logs in interactive functions