1 files changed, 103 insertions, 0 deletions
diff --git a/scripts/external_libs/dpkt-1.8.6/dpkt/gre.py b/scripts/external_libs/dpkt-1.8.6/dpkt/gre.py
new file mode 100644
index 00000000..4d462edc
--- /dev/null
+++ b/scripts/external_libs/dpkt-1.8.6/dpkt/gre.py
@@ -0,0 +1,103 @@
+# $Id: gre.py 75 2010-08-03 14:42:19Z jon.oberheide $
+
+"""Generic Routing Encapsulation."""
+
+import struct
+import dpkt
+
+GRE_CP = 0x8000  # Checksum Present
+GRE_RP = 0x4000  # Routing Present
+GRE_KP = 0x2000  # Key Present
+GRE_SP = 0x1000  # Sequence Present
+GRE_SS = 0x0800  # Strict Source Route
+GRE_AP = 0x0080  # Acknowledgment Present
+
+GRE_opt_fields = (
+    (GRE_CP|GRE_RP, 'sum', 'H'), (GRE_CP|GRE_RP, 'off', 'H'),
+    (GRE_KP, 'key', 'I'), (GRE_SP, 'seq', 'I'), (GRE_AP, 'ack', 'I')
+    )
+class GRE(dpkt.Packet):
+    __hdr__ = (
+        ('flags', 'H', 0),
+        ('p', 'H', 0x0800), # ETH_TYPE_IP
+        )
+    _protosw = {}
+    sre = ()
+    def get_v(self):
+        return self.flags & 0x7
+    def set_v(self, v):
+        self.flags = (self.flags & ~0x7) | (v & 0x7)
+    v = property(get_v, set_v)
+
+    def get_recur(self):
+        return (self.flags >> 5) & 0x7
+    def set_recur(self, v):
+        self.flags = (self.flags & ~0xe0) | ((v & 0x7) << 5)
+    recur = property(get_recur, set_recur)
+    
+    class SRE(dpkt.Packet):
+        __hdr__ = [
+            ('family', 'H', 0),
+            ('off', 'B', 0),
+            ('len', 'B', 0)
+            ]
+        def unpack(self, buf):
+            dpkt.Packet.unpack(self, buf)
+            self.data = self.data[:self.len]
+
+    def opt_fields_fmts(self):
+        if self.v == 0:
+            fields, fmts = [], []
+            opt_fields = GRE_opt_fields
+        else:
+            fields, fmts = [ 'len', 'callid' ], [ 'H', 'H' ]
+            opt_fields = GRE_opt_fields[-2:]
+        for flags, field, fmt in opt_fields:
+            if self.flags & flags:
+                fields.append(field)
+                fmts.append(fmt)
+        return fields, fmts
+    
+    def unpack(self, buf):
+        dpkt.Packet.unpack(self, buf)
+        fields, fmts = self.opt_fields_fmts()
+        if fields:
+            fmt = ''.join(fmts)
+            fmtlen = struct.calcsize(fmt)
+            vals = struct.unpack(fmt, self.data[:fmtlen])
+            self.data = self.data[fmtlen:]
+            self.__dict__.update(dict(zip(fields, vals)))
+        if self.flags & GRE_RP:
+            l = []
+            while True:
+                sre = self.SRE(self.data)
+                self.data = self.data[len(sre):]
+                l.append(sre)
+                if not sre.len:
+                    break
+            self.sre = l
+        self.data = ethernet.Ethernet._typesw[self.p](self.data)
+        setattr(self, self.data.__class__.__name__.lower(), self.data)
+    
+    def __len__(self):
+        opt_fmtlen = struct.calcsize(''.join(self.opt_fields_fmts()[1]))
+        return self.__hdr_len__ + opt_fmtlen + \
+               sum(map(len, self.sre)) + len(self.data)
+
+    # XXX - need to fix up repr to display optional fields...
+    
+    def __str__(self):
+        fields, fmts = self.opt_fields_fmts()
+        if fields:
+            vals = []
+            for f in fields:
+                vals.append(getattr(self, f))
+            opt_s = struct.pack(''.join(fmts), *vals)
+        else:
+            opt_s = ''
+        return self.pack_hdr() + opt_s + ''.join(map(str, self.sre)) + \
+               str(self.data)
+
+# XXX - auto-load GRE dispatch table from Ethernet dispatch table
+import ethernet
+GRE._protosw.update(ethernet.Ethernet._typesw)