dos2unix

1 files changed, 113 insertions, 113 deletions

diff --git a/project2/proj2_s4498062/dns/domainname.py b/project2/proj2_s4498062/dns/domainname.py
index 09f98fa..85e14bf 100644
--- a/project2/proj2_s4498062/dns/domainname.py
+++ b/project2/proj2_s4498062/dns/domainname.py
@@ -1,113 +1,113 @@
-#!/usr/bin/env python2

-

-""" Parsing and composing domain names

-

-This module contains two classes for converting domain names to and from bytes.

-You won't have to use these classes. They're used internally in Message,

-Question, ResourceRecord and RecordData. You can read section 4.1.4 of RFC 1035

-if you want more info.

-"""

-

-import struct

-

-

-class Composer(object):

-    def __init__(self):

-        self.offsets = dict()

-    

-    def to_bytes(self, offset, dnames):

-        # Convert each domain name in to bytes

-        result = b""

-        for i, dname in enumerate(dnames):

-            # Split domain name into labels

-            labels = dname.split(".")

-            

-            # Determine keys of subdomains in offset dict

-            keys = []

-            for label in reversed(labels):

-                name = label

-                if keys:

-                     name += "." + keys[-1]

-                keys.append(name)

-            keys.reverse()

-

-            # Convert label to bytes

-            add_null = True

-            for j, label in enumerate(labels):

-                if keys[j] in self.offsets:

-                    offset = self.offsets[keys[j]]

-                    pointer = (3 << 14) + offset

-                    result += struct.pack("!H", pointer)

-                    add_null = False

-                    offset += 2

-                    break

-                else:

-                    self.offsets[keys[j]] = offset

-                    result += struct.pack("!B{}s".format(len(label)),

-                              len(label),

-                              label)

-                    offset += 1 + len(label)

-

-            # Add null character at end

-            if add_null:

-                result += b"\x00"

-                offset += 1

-

-        return result

-

-

-class Parser(object):

-    def __init__(self):

-        self.labels = dict()

-

-    def from_bytes(self, packet, offset, num):

-        begin_offset = offset

-        dnames = []

-

-        # Read the domain names

-        for i in range(num):

-            # Read a new domain name

-            dname = ""

-            prev_offsets = []

-            done = False

-            while done is False:

-                # Read length of next label

-                llength = struct.unpack_from("!B", packet, offset)[0]

-

-                # Done reading domain when length is zero

-                if llength == 0:

-                    offset += 1

-                    break

-                

-                # Compression label

-                elif (llength >> 6) == 3:

-                    new_offset = offset + 2

-                    target = struct.unpack_from("!H", packet, offset)[0]

-                    target -= 3 << 14

-                    label = self.labels[target]

-                    done = True

-

-                # Normal label

-                else:

-                    new_offset = offset + llength + 1

-                    label = struct.unpack_from("{}s".format(llength),

-                            packet, offset+1)[0]

-

-                # Add label to dictionary

-                self.labels[offset] = label

-                for prev_offset in prev_offsets:

-                    self.labels[prev_offset] += "." + label

-                prev_offsets.append(offset)

-

-                # Update offset

-                offset = new_offset

-

-                # Append label to domain name

-                if len(dname) > 0:

-                    dname += "."

-                dname += label

-

-            # Append domain name to list

-            dnames.append(dname)

-        

-        return dnames, offset

+#!/usr/bin/env python2
+
+""" Parsing and composing domain names
+
+This module contains two classes for converting domain names to and from bytes.
+You won't have to use these classes. They're used internally in Message,
+Question, ResourceRecord and RecordData. You can read section 4.1.4 of RFC 1035
+if you want more info.
+"""
+
+import struct
+
+
+class Composer(object):
+    def __init__(self):
+        self.offsets = dict()
+    
+    def to_bytes(self, offset, dnames):
+        # Convert each domain name in to bytes
+        result = b""
+        for i, dname in enumerate(dnames):
+            # Split domain name into labels
+            labels = dname.split(".")
+            
+            # Determine keys of subdomains in offset dict
+            keys = []
+            for label in reversed(labels):
+                name = label
+                if keys:
+                     name += "." + keys[-1]
+                keys.append(name)
+            keys.reverse()
+
+            # Convert label to bytes
+            add_null = True
+            for j, label in enumerate(labels):
+                if keys[j] in self.offsets:
+                    offset = self.offsets[keys[j]]
+                    pointer = (3 << 14) + offset
+                    result += struct.pack("!H", pointer)
+                    add_null = False
+                    offset += 2
+                    break
+                else:
+                    self.offsets[keys[j]] = offset
+                    result += struct.pack("!B{}s".format(len(label)),
+                              len(label),
+                              label)
+                    offset += 1 + len(label)
+
+            # Add null character at end
+            if add_null:
+                result += b"\x00"
+                offset += 1
+
+        return result
+
+
+class Parser(object):
+    def __init__(self):
+        self.labels = dict()
+
+    def from_bytes(self, packet, offset, num):
+        begin_offset = offset
+        dnames = []
+
+        # Read the domain names
+        for i in range(num):
+            # Read a new domain name
+            dname = ""
+            prev_offsets = []
+            done = False
+            while done is False:
+                # Read length of next label
+                llength = struct.unpack_from("!B", packet, offset)[0]
+
+                # Done reading domain when length is zero
+                if llength == 0:
+                    offset += 1
+                    break
+                
+                # Compression label
+                elif (llength >> 6) == 3:
+                    new_offset = offset + 2
+                    target = struct.unpack_from("!H", packet, offset)[0]
+                    target -= 3 << 14
+                    label = self.labels[target]
+                    done = True
+
+                # Normal label
+                else:
+                    new_offset = offset + llength + 1
+                    label = struct.unpack_from("{}s".format(llength),
+                            packet, offset+1)[0]
+
+                # Add label to dictionary
+                self.labels[offset] = label
+                for prev_offset in prev_offsets:
+                    self.labels[prev_offset] += "." + label
+                prev_offsets.append(offset)
+
+                # Update offset
+                offset = new_offset
+
+                # Append label to domain name
+                if len(dname) > 0:
+                    dname += "."
+                dname += label
+
+            # Append domain name to list
+            dnames.append(dname)
+        
+        return dnames, offset