diff --git a/README.md b/README.md
index 0505b8d..4978720 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,6 @@
 [![coveralls](http://img.shields.io/coveralls/kbandla/dpkt.svg)](https://coveralls.io/r/kbandla/dpkt)
 [![landscape](https://landscape.io/github/kbandla/dpkt/master/landscape.svg)](https://landscape.io/github/kbandla/dpkt/master)
 [![version](http://img.shields.io/pypi/v/dpkt.svg)](https://pypi.python.org/pypi/dpkt)
-[![downloads](https://img.shields.io/pypi/dm/dpkt.svg)](https://pypi.python.org/pypi/dpkt)
 
 [![wheel](https://img.shields.io/pypi/wheel/dpkt.svg)](https://pypi.python.org/pypi/dpkt)
 [![supported-versions](https://img.shields.io/pypi/pyversions/dpkt.svg)](https://pypi.python.org/pypi/dpkt)
diff --git a/README.rst b/README.rst
index b4e1b96..2a414cd 100644
--- a/README.rst
+++ b/README.rst
@@ -3,8 +3,8 @@
 dpkt
 ====
 
-| |travis| |coveralls| |landscape| |downloads| 
-| |version| |wheel| |supported-versions| |supported-implementations|
+| |travis| |coveralls| |landscape| |version|
+| |wheel| |supported-versions| |supported-implementations|
 
 .. |travis| image:: http://img.shields.io/travis/kbandla/dpkt.svg
     :alt: Travis-CI Build Status
@@ -22,10 +22,6 @@
     :alt: PyPI Package latest release
     :target: https://pypi.python.org/pypi/dpkt
 
-.. |downloads| image:: http://img.shields.io/pypi/dm/dpkt.svg
-    :alt: PyPI Package monthly downloads
-    :target: https://pypi.python.org/pypi/dpkt
-
 .. |wheel| image:: https://img.shields.io/pypi/wheel/dpkt.svg 
     :alt: PyPI Wheel
     :target: https://pypi.python.org/pypi/dpkt
diff --git a/dpkt/aim.py b/dpkt/aim.py
index 86d3b08..5b7bd4c 100644
--- a/dpkt/aim.py
+++ b/dpkt/aim.py
@@ -60,10 +60,10 @@
     try:
         t, l = struct.unpack('>HH', buf[:n])
     except struct.error:
-        raise dpkt.UnpackError
+        raise dpkt.UnpackError('invalid type, length fields')
     v = buf[n:n + l]
     if len(v) < l:
-        raise dpkt.NeedData
+        raise dpkt.NeedData('%d left, %d needed' % (len(v), l))
     buf = buf[n + l:]
     return t, l, v, buf
 
@@ -71,3 +71,58 @@
 
 # TOC 2.0: http://www.firestuff.org/projects/firetalk/doc/toc2.txt
 
+def testAIM():
+    testdata = b'*\x02\xac\xf3\x00\x81\x00\x03\x00\x0b\x00\x00\xfaEUd\x0eusrnameremoved\x00\x00\x00\n\x00\x01\x00\x02\x12\x90\x00D\x00\x01\x00\x00\x03\x00\x04X\x90T6\x00E\x00\x04\x00\x00\x0f\x93\x00!\x00\x08\x00\x85\x00}\x00}\x00\x00\x00A\x00\x01\x00\x007\x00\x04\x00\x00\x00\x00\x00\r\x00\x00\x00\x19\x00\x00\x00\x1d\x00$\x00\x00\x00\x05\x02\x01\xd2\x04r\x00\x01\x00\x05\x02\x01\xd2\x04r\x00\x03\x00\x05+\x00\x00*\xcc\x00\x81\x00\x05+\x00\x00\x13\xf1'
+
+    flap = FLAP(testdata)
+    assert flap.ast == 0x2a
+    assert flap.type == 0x02
+    assert flap.seq == 44275
+    assert flap.len == 129
+    assert flap.data == b'\x00\x03\x00\x0b\x00\x00\xfaEUd\x0eusrnameremoved\x00\x00\x00\n\x00\x01\x00\x02\x12\x90\x00D\x00\x01\x00\x00\x03\x00\x04X\x90T6\x00E\x00\x04\x00\x00\x0f\x93\x00!\x00\x08\x00\x85\x00}\x00}\x00\x00\x00A\x00\x01\x00\x007\x00\x04\x00\x00\x00\x00\x00\r\x00\x00\x00\x19\x00\x00\x00\x1d\x00$\x00\x00\x00\x05\x02\x01\xd2\x04r\x00\x01\x00\x05\x02\x01\xd2\x04r\x00\x03\x00\x05+\x00\x00*\xcc\x00\x81\x00\x05+\x00\x00\x13\xf1'
+
+    snac = SNAC(flap.data)
+    assert snac.family == 3
+    assert snac.subtype == 11
+    assert snac.flags == 0
+    assert snac.reqid == 0xfa455564
+    assert snac.data == b'\x0eusrnameremoved\x00\x00\x00\n\x00\x01\x00\x02\x12\x90\x00D\x00\x01\x00\x00\x03\x00\x04X\x90T6\x00E\x00\x04\x00\x00\x0f\x93\x00!\x00\x08\x00\x85\x00}\x00}\x00\x00\x00A\x00\x01\x00\x007\x00\x04\x00\x00\x00\x00\x00\r\x00\x00\x00\x19\x00\x00\x00\x1d\x00$\x00\x00\x00\x05\x02\x01\xd2\x04r\x00\x01\x00\x05\x02\x01\xd2\x04r\x00\x03\x00\x05+\x00\x00*\xcc\x00\x81\x00\x05+\x00\x00\x13\xf1'
+
+    #skip over the buddyname and TLV count in Oncoming Buddy message
+    tlvdata = snac.data[19:]
+
+    tlvCount = 0
+    while tlvdata:
+        t, l, v, tlvdata = tlv(tlvdata)
+        tlvCount += 1
+        if tlvCount == 1:
+            # just check function return for first TLV
+            assert t == 0x01
+            assert l == 2
+            assert v == b'\x12\x90'
+            assert tlvdata == b'\x00D\x00\x01\x00\x00\x03\x00\x04X\x90T6\x00E\x00\x04\x00\x00\x0f\x93\x00!\x00\x08\x00\x85\x00}\x00}\x00\x00\x00A\x00\x01\x00\x007\x00\x04\x00\x00\x00\x00\x00\r\x00\x00\x00\x19\x00\x00\x00\x1d\x00$\x00\x00\x00\x05\x02\x01\xd2\x04r\x00\x01\x00\x05\x02\x01\xd2\x04r\x00\x03\x00\x05+\x00\x00*\xcc\x00\x81\x00\x05+\x00\x00\x13\xf1'
+
+    # make sure we extracted 10 TLVs
+    assert tlvCount == 10
+
+
+def testExceptions():
+    testdata = b'xxxxxx'
+    try:
+        flap = FLAP(testdata)
+    except dpkt.UnpackError as e:
+        assert str(e) == 'invalid FLAP header'
+    testdata = b'*\x02\x12\x34\x00\xff'
+    try:
+        flap = FLAP(testdata)
+    except dpkt.NeedData as e:
+        assert str(e) == '0 left, 255 needed'
+    try:
+        t, l, v, _ = tlv(b'x')
+    except dpkt.UnpackError as e:
+        assert str(e) == 'invalid type, length fields'
+
+    try:
+        t, l, v, _ = tlv(b'\x00\x01\x00\xff')
+    except dpkt.NeedData as e:
+        assert str(e) == '0 left, 255 needed'
diff --git a/dpkt/http.py b/dpkt/http.py
index b295af2..9df1f9b 100644
--- a/dpkt/http.py
+++ b/dpkt/http.py
@@ -3,14 +3,19 @@
 """Hypertext Transfer Protocol."""
 from __future__ import print_function
 from __future__ import absolute_import
+try:
+    from collections import OrderedDict
+except ImportError:
+    # Python 2.6
+    OrderedDict = dict
 
 from . import dpkt
-from .compat import StringIO, iteritems
+from .compat import BytesIO, iteritems
 
 
 def parse_headers(f):
     """Return dict of HTTP headers parsed from a file object."""
-    d = {}
+    d = OrderedDict()
     while 1:
         # The following logic covers two kinds of loop exit criteria.
         # 1) If the header is valid, when we reached the end of the header,
@@ -19,7 +24,7 @@
         # 2) If this is a weird header, which do not ends with '\r\n',
         #    f.readline() would return with '', then after strip(),
         #    we still get an empty string, also break the loop.
-        line = f.readline().strip()
+        line = f.readline().strip().decode("ascii", "ignore")
         if not line:
             break
         l = line.split(':', 1)
@@ -58,7 +63,7 @@
                 break
         if not found_end:
             raise dpkt.NeedData('premature end of chunked body')
-        body = ''.join(l)
+        body = b''.join(l)
     elif 'content-length' in headers:
         n = int(headers['content-length'])
         body = f.read(n)
@@ -68,7 +73,7 @@
         body = f.read()
     else:
         # XXX - need to handle HTTP/0.9
-        body = ''
+        body = b''
     return body
 
 
@@ -91,8 +96,9 @@
         if args:
             self.unpack(args[0])
         else:
-            self.headers = {}
-            self.body = ''
+            self.headers = OrderedDict()
+            self.body = b''
+            self.data = b''
             # NOTE: changing this to iteritems breaks py3 compatibility
             for k, v in self.__hdr_defaults__.items():
                 setattr(self, k, v)
@@ -100,7 +106,7 @@
                 setattr(self, k, v)
 
     def unpack(self, buf, is_body_allowed=True):
-        f = StringIO(buf)
+        f = BytesIO(buf)
         # Parse headers
         self.headers = parse_headers(f)
         # Parse body
@@ -116,7 +122,16 @@
         return len(str(self))
 
     def __str__(self):
-        return '%s\r\n%s' % (self.pack_hdr(), self.body)
+        return '%s\r\n%s' % (self.pack_hdr(), self.body.decode("utf8", "ignore"))
+
+    def __bytes__(self):
+        # Not using byte interpolation to preserve Python 3.4 compatibility. The extra
+        # \r\n doesn't get trimmed from the bytes, so it's necessary to omit the spacing
+        # one when building the output if there's no body
+        if self.body:
+            return self.pack_hdr().encode("ascii", "ignore") + b'\r\n' + self.body
+        else:
+            return self.pack_hdr().encode("ascii", "ignore")
 
 
 class Request(Message):
@@ -150,8 +165,8 @@
     __proto = 'HTTP'
 
     def unpack(self, buf):
-        f = StringIO(buf)
-        line = f.readline()
+        f = BytesIO(buf)
+        line = f.readline().decode("ascii", "ignore")
         l = line.strip().split()
         if len(l) < 2:
             raise dpkt.UnpackError('invalid request: %r' % line)
@@ -172,6 +187,11 @@
         return '%s %s %s/%s\r\n' % (self.method, self.uri, self.__proto,
                                     self.version) + Message.__str__(self)
 
+    def __bytes__(self):
+        str_out = '%s %s %s/%s\r\n' % (self.method, self.uri, self.__proto,
+                                       self.version)
+        return str_out.encode("ascii", "ignore") + Message.__bytes__(self)
+
 
 class Response(Message):
     """Hypertext Transfer Protocol Response.
@@ -191,9 +211,9 @@
     __proto = 'HTTP'
 
     def unpack(self, buf):
-        f = StringIO(buf)
+        f = BytesIO(buf)
         line = f.readline()
-        l = line.strip().split(None, 2)
+        l = line.strip().decode("ascii", "ignore").split(None, 2)
         if len(l) < 2 or not l[0].startswith(self.__proto) or not l[1].isdigit():
             raise dpkt.UnpackError('invalid response: %r' % line)
         self.version = l[0][len(self.__proto) + 1:]
@@ -216,13 +236,18 @@
         return '%s/%s %s %s\r\n' % (self.__proto, self.version, self.status,
                                     self.reason) + Message.__str__(self)
 
+    def __bytes__(self):
+        str_out = '%s/%s %s %s\r\n' % (self.__proto, self.version, self.status,
+                                       self.reason) + Message.__str__(self)
+        return str_out.encode("ascii", "ignore") + Message.__bytes__(self)
+
 
 def test_parse_request():
-    s = """POST /main/redirect/ab/1,295,,00.html HTTP/1.0\r\nReferer: http://www.email.com/login/snap/login.jhtml\r\nConnection: Keep-Alive\r\nUser-Agent: Mozilla/4.75 [en] (X11; U; OpenBSD 2.8 i386; Nav)\r\nHost: ltd.snap.com\r\nAccept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*\r\nAccept-Encoding: gzip\r\nAccept-Language: en\r\nAccept-Charset: iso-8859-1,*,utf-8\r\nContent-type: application/x-www-form-urlencoded\r\nContent-length: 61\r\n\r\nsn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www"""
+    s = b"""POST /main/redirect/ab/1,295,,00.html HTTP/1.0\r\nReferer: http://www.email.com/login/snap/login.jhtml\r\nConnection: Keep-Alive\r\nUser-Agent: Mozilla/4.75 [en] (X11; U; OpenBSD 2.8 i386; Nav)\r\nHost: ltd.snap.com\r\nAccept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*\r\nAccept-Encoding: gzip\r\nAccept-Language: en\r\nAccept-Charset: iso-8859-1,*,utf-8\r\nContent-type: application/x-www-form-urlencoded\r\nContent-length: 61\r\n\r\nsn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www"""
     r = Request(s)
     assert r.method == 'POST'
     assert r.uri == '/main/redirect/ab/1,295,,00.html'
-    assert r.body == 'sn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www'
+    assert r.body == b'sn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www'
     assert r.headers['content-type'] == 'application/x-www-form-urlencoded'
     try:
         Request(s[:60])
@@ -238,18 +263,23 @@
     r.uri = '/foo/bar/baz.html'
     r.headers['content-type'] = 'text/plain'
     r.headers['content-length'] = '5'
-    r.body = 'hello'
+    r.body = b'hello'
     s = str(r)
     assert s.startswith('POST /foo/bar/baz.html HTTP/1.0\r\n')
     assert s.endswith('\r\n\r\nhello')
     assert '\r\ncontent-length: 5\r\n' in s
     assert '\r\ncontent-type: text/plain\r\n' in s
-    r = Request(str(r))
-    assert str(r) == s
+    s = bytes(r)
+    assert s.startswith(b'POST /foo/bar/baz.html HTTP/1.0\r\n')
+    assert s.endswith(b'\r\n\r\nhello')
+    assert b'\r\ncontent-length: 5\r\n' in s
+    assert b'\r\ncontent-type: text/plain\r\n' in s
+    r = Request(bytes(r))
+    assert bytes(r) == s
 
 
 def test_chunked_response():
-    s = """HTTP/1.1 200 OK\r\nCache-control: no-cache\r\nPragma: no-cache\r\nContent-Type: text/javascript; charset=utf-8\r\nContent-Encoding: gzip\r\nTransfer-Encoding: chunked\r\nSet-Cookie: S=gmail=agg:gmail_yj=v2s:gmproxy=JkU; Domain=.google.com; Path=/\r\nServer: GFE/1.3\r\nDate: Mon, 12 Dec 2005 22:33:23 GMT\r\n\r\na\r\n\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x00\r\n152\r\nm\x91MO\xc4 \x10\x86\xef\xfe\n\x82\xc9\x9eXJK\xe9\xb6\xee\xc1\xe8\x1e6\x9e4\xf1\xe0a5\x86R\xda\x12Yh\x80\xba\xfa\xef\x85\xee\x1a/\xf21\x99\x0c\xef0<\xc3\x81\xa0\xc3\x01\xe6\x10\xc1<\xa7eYT5\xa1\xa4\xac\xe1\xdb\x15:\xa4\x9d\x0c\xfa5K\x00\xf6.\xaa\xeb\x86\xd5y\xcdHY\x954\x8e\xbc*h\x8c\x8e!L7Y\xe6\'\xeb\x82WZ\xcf>8\x1ed\x87\x851X\xd8c\xe6\xbc\x17Z\x89\x8f\xac \x84e\xde\n!]\x96\x17i\xb5\x02{{\xc2z0\x1e\x0f#7\x9cw3v\x992\x9d\xfc\xc2c8\xea[/EP\xd6\xbc\xce\x84\xd0\xce\xab\xf7`\'\x1f\xacS\xd2\xc7\xd2\xfb\x94\x02N\xdc\x04\x0f\xee\xba\x19X\x03TtW\xd7\xb4\xd9\x92\n\xbcX\xa7;\xb0\x9b\'\x10$?F\xfd\xf3CzPt\x8aU\xef\xb8\xc8\x8b-\x18\xed\xec<\xe0\x83\x85\x08!\xf8"[\xb0\xd3j\x82h\x93\xb8\xcf\xd8\x9b\xba\xda\xd0\x92\x14\xa4a\rc\reM\xfd\x87=X;h\xd9j;\xe0db\x17\xc2\x02\xbd\xb0F\xc2in#\xfb:\xb6\xc4x\x15\xd6\x9f\x8a\xaf\xcf)\x0b^\xbc\xe7i\x11\x80\x8b\x00D\x01\xd8/\x82x\xf6\xd8\xf7J(\xae/\x11p\x1f+\xc4p\t:\xfe\xfd\xdf\xa3Y\xfa\xae4\x7f\x00\xc5\xa5\x95\xa1\xe2\x01\x00\x00\r\n0\r\n\r\n"""
+    s = b"""HTTP/1.1 200 OK\r\nCache-control: no-cache\r\nPragma: no-cache\r\nContent-Type: text/javascript; charset=utf-8\r\nContent-Encoding: gzip\r\nTransfer-Encoding: chunked\r\nSet-Cookie: S=gmail=agg:gmail_yj=v2s:gmproxy=JkU; Domain=.google.com; Path=/\r\nServer: GFE/1.3\r\nDate: Mon, 12 Dec 2005 22:33:23 GMT\r\n\r\na\r\n\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x00\r\n152\r\nm\x91MO\xc4 \x10\x86\xef\xfe\n\x82\xc9\x9eXJK\xe9\xb6\xee\xc1\xe8\x1e6\x9e4\xf1\xe0a5\x86R\xda\x12Yh\x80\xba\xfa\xef\x85\xee\x1a/\xf21\x99\x0c\xef0<\xc3\x81\xa0\xc3\x01\xe6\x10\xc1<\xa7eYT5\xa1\xa4\xac\xe1\xdb\x15:\xa4\x9d\x0c\xfa5K\x00\xf6.\xaa\xeb\x86\xd5y\xcdHY\x954\x8e\xbc*h\x8c\x8e!L7Y\xe6\'\xeb\x82WZ\xcf>8\x1ed\x87\x851X\xd8c\xe6\xbc\x17Z\x89\x8f\xac \x84e\xde\n!]\x96\x17i\xb5\x02{{\xc2z0\x1e\x0f#7\x9cw3v\x992\x9d\xfc\xc2c8\xea[/EP\xd6\xbc\xce\x84\xd0\xce\xab\xf7`\'\x1f\xacS\xd2\xc7\xd2\xfb\x94\x02N\xdc\x04\x0f\xee\xba\x19X\x03TtW\xd7\xb4\xd9\x92\n\xbcX\xa7;\xb0\x9b\'\x10$?F\xfd\xf3CzPt\x8aU\xef\xb8\xc8\x8b-\x18\xed\xec<\xe0\x83\x85\x08!\xf8"[\xb0\xd3j\x82h\x93\xb8\xcf\xd8\x9b\xba\xda\xd0\x92\x14\xa4a\rc\reM\xfd\x87=X;h\xd9j;\xe0db\x17\xc2\x02\xbd\xb0F\xc2in#\xfb:\xb6\xc4x\x15\xd6\x9f\x8a\xaf\xcf)\x0b^\xbc\xe7i\x11\x80\x8b\x00D\x01\xd8/\x82x\xf6\xd8\xf7J(\xae/\x11p\x1f+\xc4p\t:\xfe\xfd\xdf\xa3Y\xfa\xae4\x7f\x00\xc5\xa5\x95\xa1\xe2\x01\x00\x00\r\n0\r\n\r\n"""
     r = Response(s)
     assert r.version == '1.1'
     assert r.status == '200'
@@ -257,40 +287,40 @@
 
 
 def test_multicookie_response():
-    s = """HTTP/1.x 200 OK\r\nSet-Cookie: first_cookie=cookie1; path=/; domain=.example.com\r\nSet-Cookie: second_cookie=cookie2; path=/; domain=.example.com\r\nContent-Length: 0\r\n\r\n"""
+    s = b"""HTTP/1.x 200 OK\r\nSet-Cookie: first_cookie=cookie1; path=/; domain=.example.com\r\nSet-Cookie: second_cookie=cookie2; path=/; domain=.example.com\r\nContent-Length: 0\r\n\r\n"""
     r = Response(s)
     assert type(r.headers['set-cookie']) is list
     assert len(r.headers['set-cookie']) == 2
 
 
 def test_noreason_response():
-    s = """HTTP/1.1 200 \r\n\r\n"""
+    s = b"""HTTP/1.1 200 \r\n\r\n"""
     r = Response(s)
     assert r.reason == ''
-    assert str(r) == s
+    assert bytes(r) == s
 
 
 def test_body_forbidden_response():
-    s = 'HTTP/1.1 304 Not Modified\r\n'\
-        'Content-Type: text/css\r\n'\
-        'Last-Modified: Wed, 14 Jan 2009 16:42:11 GMT\r\n'\
-        'ETag: "3a7-496e15e3"\r\n'\
-        'Cache-Control: private, max-age=414295\r\n'\
-        'Date: Wed, 22 Sep 2010 17:55:54 GMT\r\n'\
-        'Connection: keep-alive\r\n'\
-        'Vary: Accept-Encoding\r\n\r\n'\
-        'HTTP/1.1 200 OK\r\n'\
-        'Server: Sun-ONE-Web-Server/6.1\r\n'\
-        'ntCoent-length: 257\r\n'\
-        'Content-Type: application/x-javascript\r\n'\
-        'Last-Modified: Wed, 06 Jan 2010 19:34:06 GMT\r\n'\
-        'ETag: "101-4b44e5ae"\r\n'\
-        'Accept-Ranges: bytes\r\n'\
-        'Content-Encoding: gzip\r\n'\
-        'Cache-Control: private, max-age=439726\r\n'\
-        'Date: Wed, 22 Sep 2010 17:55:54 GMT\r\n'\
-        'Connection: keep-alive\r\n'\
-        'Vary: Accept-Encoding\r\n'
+    s = b'HTTP/1.1 304 Not Modified\r\n'\
+        b'Content-Type: text/css\r\n'\
+        b'Last-Modified: Wed, 14 Jan 2009 16:42:11 GMT\r\n'\
+        b'ETag: "3a7-496e15e3"\r\n'\
+        b'Cache-Control: private, max-age=414295\r\n'\
+        b'Date: Wed, 22 Sep 2010 17:55:54 GMT\r\n'\
+        b'Connection: keep-alive\r\n'\
+        b'Vary: Accept-Encoding\r\n\r\n'\
+        b'HTTP/1.1 200 OK\r\n'\
+        b'Server: Sun-ONE-Web-Server/6.1\r\n'\
+        b'ntCoent-length: 257\r\n'\
+        b'Content-Type: application/x-javascript\r\n'\
+        b'Last-Modified: Wed, 06 Jan 2010 19:34:06 GMT\r\n'\
+        b'ETag: "101-4b44e5ae"\r\n'\
+        b'Accept-Ranges: bytes\r\n'\
+        b'Content-Encoding: gzip\r\n'\
+        b'Cache-Control: private, max-age=439726\r\n'\
+        b'Date: Wed, 22 Sep 2010 17:55:54 GMT\r\n'\
+        b'Connection: keep-alive\r\n'\
+        b'Vary: Accept-Encoding\r\n'
     result = []
     while s:
         msg = Response(s)
@@ -302,19 +332,19 @@
 
 
 def test_request_version():
-    s = """GET / HTTP/1.0\r\n\r\n"""
+    s = b"""GET / HTTP/1.0\r\n\r\n"""
     r = Request(s)
     assert r.method == 'GET'
     assert r.uri == '/'
     assert r.version == '1.0'
 
-    s = """GET /\r\n\r\n"""
+    s = b"""GET /\r\n\r\n"""
     r = Request(s)
     assert r.method == 'GET'
     assert r.uri == '/'
     assert r.version == '0.9'
 
-    s = """GET / CHEESE/1.0\r\n\r\n"""
+    s = b"""GET / CHEESE/1.0\r\n\r\n"""
     try:
         Request(s)
         assert "invalid protocol version parsed!"
@@ -324,43 +354,43 @@
 
 def test_invalid_header():
     # valid header.
-    s = 'POST /main/redirect/ab/1,295,,00.html HTTP/1.0\r\n' \
-        'Referer: http://www.email.com/login/snap/login.jhtml\r\n' \
-        'Connection: Keep-Alive\r\n' \
-        'User-Agent: Mozilla/4.75 [en] (X11; U; OpenBSD 2.8 i386; Nav)\r\n' \
-        'Host: ltd.snap.com\r\n' \
-        'Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*\r\n' \
-        'Accept-Encoding: gzip\r\n' \
-        'Accept-Language: en\r\n' \
-        'Accept-Charset: iso-8859-1,*,utf-8\r\n' \
-        'Content-type: application/x-www-form-urlencoded\r\n' \
-        'Content-length: 61\r\n\r\n' \
-        'sn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www'
+    s = b'POST /main/redirect/ab/1,295,,00.html HTTP/1.0\r\n' \
+        b'Referer: http://www.email.com/login/snap/login.jhtml\r\n' \
+        b'Connection: Keep-Alive\r\n' \
+        b'User-Agent: Mozilla/4.75 [en] (X11; U; OpenBSD 2.8 i386; Nav)\r\n' \
+        b'Host: ltd.snap.com\r\n' \
+        b'Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*\r\n' \
+        b'Accept-Encoding: gzip\r\n' \
+        b'Accept-Language: en\r\n' \
+        b'Accept-Charset: iso-8859-1,*,utf-8\r\n' \
+        b'Content-type: application/x-www-form-urlencoded\r\n' \
+        b'Content-length: 61\r\n\r\n' \
+        b'sn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www'
     r = Request(s)
     assert r.method == 'POST'
     assert r.uri == '/main/redirect/ab/1,295,,00.html'
-    assert r.body == 'sn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www'
+    assert r.body == b'sn=em&mn=dtest4&pw=this+is+atest&fr=true&login=Sign+in&od=www'
     assert r.headers['content-type'] == 'application/x-www-form-urlencoded'
 
     # invalid header.
-    s_weird_end = 'POST /main/redirect/ab/1,295,,00.html HTTP/1.0\r\n' \
-        'Referer: http://www.email.com/login/snap/login.jhtml\r\n' \
-        'Connection: Keep-Alive\r\n' \
-        'User-Agent: Mozilla/4.75 [en] (X11; U; OpenBSD 2.8 i386; Nav)\r\n' \
-        'Host: ltd.snap.com\r\n' \
-        'Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*\r\n' \
-        'Accept-Encoding: gzip\r\n' \
-        'Accept-Language: en\r\n' \
-        'Accept-Charset: iso-8859-1,*,utf-8\r\n' \
-        'Content-type: application/x-www-form-urlencoded\r\n' \
-        'Cookie: TrackID=1PWdcr3MO_C611BGW'
+    s_weird_end = b'POST /main/redirect/ab/1,295,,00.html HTTP/1.0\r\n' \
+        b'Referer: http://www.email.com/login/snap/login.jhtml\r\n' \
+        b'Connection: Keep-Alive\r\n' \
+        b'User-Agent: Mozilla/4.75 [en] (X11; U; OpenBSD 2.8 i386; Nav)\r\n' \
+        b'Host: ltd.snap.com\r\n' \
+        b'Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*\r\n' \
+        b'Accept-Encoding: gzip\r\n' \
+        b'Accept-Language: en\r\n' \
+        b'Accept-Charset: iso-8859-1,*,utf-8\r\n' \
+        b'Content-type: application/x-www-form-urlencoded\r\n' \
+        b'Cookie: TrackID=1PWdcr3MO_C611BGW'
     r = Request(s_weird_end)
     assert r.method == 'POST'
     assert r.uri == '/main/redirect/ab/1,295,,00.html'
     assert r.headers['content-type'] == 'application/x-www-form-urlencoded'
 
     # messy header.
-    s_messy_header = 'aaaaaaaaa\r\nbbbbbbbbb'
+    s_messy_header = b'aaaaaaaaa\r\nbbbbbbbbb'
     try:
         r = Request(s_messy_header)
     except dpkt.UnpackError:
@@ -373,6 +403,30 @@
         assert False
 
 
+def test_gzip_response():
+    import zlib
+    # valid response, compressed using gzip
+    s = b'HTTP/1.0 200 OK\r\n' \
+        b'Server: SimpleHTTP/0.6 Python/2.7.12\r\n' \
+        b'Date: Fri, 10 Mar 2017 20:43:08 GMT\r\n' \
+        b'Content-type: text/plain\r\n' \
+        b'Content-Encoding: gzip\r\n' \
+        b'Content-Length: 68\r\n' \
+        b'Last-Modified: Fri, 10 Mar 2017 20:40:43 GMT\r\n\r\n' \
+        b'\x1f\x8b\x08\x00\x00\x00\x00\x00\x02\x03\x0b\xc9\xc8,V\x00\xa2D' \
+        b'\x85\xb2\xd4\xa2J\x85\xe2\xdc\xc4\x9c\x1c\x85\xb4\xcc\x9cT\x85\x92' \
+        b'|\x85\x92\xd4\xe2\x12\x85\xf4\xaa\xcc\x02\x85\xa2\xd4\xe2\x82\xfc' \
+        b'\xbc\xe2\xd4b=.\x00\x01(m\xad2\x00\x00\x00'
+    r = Response(s)
+    assert r.version == '1.0'
+    assert r.status == '200'
+    assert r.reason == 'OK'
+    # Make a zlib compressor with the appropriate gzip options
+    decompressor = zlib.decompressobj(16 + zlib.MAX_WBITS)
+    body = decompressor.decompress(r.body)
+    assert body.startswith(b'This is a very small file')
+
+
 if __name__ == '__main__':
     # Runs all the test associated with this class/file
     test_parse_request()
diff --git a/dpkt/ip.py b/dpkt/ip.py
index 451106b..49e13ce 100644
--- a/dpkt/ip.py
+++ b/dpkt/ip.py
@@ -373,6 +373,8 @@
     ip.data = u
     ip.len += len(u)
     assert (bytes(ip) == s)
+    assert (ip.v == 4)
+    assert (ip.hl == 5)
 
     ip = IP(s)
     assert (bytes(ip) == s)
diff --git a/dpkt/pim.py b/dpkt/pim.py
index 3753da6..629ae86 100644
--- a/dpkt/pim.py
+++ b/dpkt/pim.py
@@ -58,3 +58,13 @@
         if not self.sum:
             self.sum = dpkt.in_cksum(dpkt.Packet.__bytes__(self))
         return dpkt.Packet.__bytes__(self)
+
+def test_pim():
+    pimdata =  PIM(b'\x20\x00\x9f\xf4\x00\x01\x00\x02\x00\x69')
+    assert pimdata.v == 2
+    assert pimdata.type == 0
+
+    # test setters
+    pimdata.v = 3
+    pimdata.type = 1
+    assert bytes(pimdata) == b'\x31\x00\x9f\xf4\x00\x01\x00\x02\x00\x69'
diff --git a/dpkt/rtp.py b/dpkt/rtp.py
index f138908..924fb57 100644
--- a/dpkt/rtp.py
+++ b/dpkt/rtp.py
@@ -135,3 +135,29 @@
         self.csrc = buf[self.__hdr_len__:self.__hdr_len__ + self.cc * 4]
         self.data = buf[self.__hdr_len__ + self.cc * 4:]
 
+def test_rtp():
+    rtp = RTP(b"\x80\x08\x4d\x01\x00\x01\x00\xe0\x34\x3f\xfa\x34\x53\x53\x53\x56\x53\x5d\x56\x57\xd5\xd6\xd1\xde\xdf\xd3\xd9\xda\xdf\xdc\xdf\xd8\xdd\xd4\xdd\xd9\xd1\xd6\xdc\xda\xde\xdd\xc7\xc1\xdf\xdf\xda\xdb\xdd\xdd\xc4\xd9\x55\x57\xd4\x50\x44\x44\x5b\x44\x4f\x4c\x47\x40\x4c\x47\x59\x5b\x58\x5d\x56\x56\x53\x56\xd5\xd5\x54\x55\xd6\xd6\xd4\xd1\xd1\xd0\xd1\xd5\xdd\xd6\x55\xd4\xd6\xd1\xd4\xd6\xd7\xd7\xd5\xd4\xd0\xd7\xd1\xd4\xd2\xdc\xd6\xdc\xdf\xdc\xdd\xd2\xde\xdc\xd0\xdd\xdc\xd0\xd6\xd6\xd6\x55\x54\x55\x57\x57\x56\x50\x50\x5c\x5c\x52\x5d\x5d\x5f\x5e\x5d\x5e\x52\x50\x52\x56\x54\x57\x55\x55\xd4\xd7\x55\xd5\x55\x55\x55\x55\x55\x54\x57\x54\x55\x55\xd5\xd5\xd7\xd6\xd7\xd1\xd1\xd3\xd2\xd3\xd2\xd2\xd3\xd3")
+    assert (rtp.version == 2)
+    assert (rtp.p == 0)
+    assert (rtp.x == 0)
+    assert (rtp.cc == 0)
+    assert (rtp.m == 0)
+    assert (rtp.pt == 8)
+    assert (rtp.seq == 19713)
+    assert (rtp.ts == 65760)
+    assert (rtp.ssrc == 0x343ffa34)
+    assert (len(rtp) == 172)
+    assert (bytes(rtp) == b"\x80\x08\x4d\x01\x00\x01\x00\xe0\x34\x3f\xfa\x34\x53\x53\x53\x56\x53\x5d\x56\x57\xd5\xd6\xd1\xde\xdf\xd3\xd9\xda\xdf\xdc\xdf\xd8\xdd\xd4\xdd\xd9\xd1\xd6\xdc\xda\xde\xdd\xc7\xc1\xdf\xdf\xda\xdb\xdd\xdd\xc4\xd9\x55\x57\xd4\x50\x44\x44\x5b\x44\x4f\x4c\x47\x40\x4c\x47\x59\x5b\x58\x5d\x56\x56\x53\x56\xd5\xd5\x54\x55\xd6\xd6\xd4\xd1\xd1\xd0\xd1\xd5\xdd\xd6\x55\xd4\xd6\xd1\xd4\xd6\xd7\xd7\xd5\xd4\xd0\xd7\xd1\xd4\xd2\xdc\xd6\xdc\xdf\xdc\xdd\xd2\xde\xdc\xd0\xdd\xdc\xd0\xd6\xd6\xd6\x55\x54\x55\x57\x57\x56\x50\x50\x5c\x5c\x52\x5d\x5d\x5f\x5e\x5d\x5e\x52\x50\x52\x56\x54\x57\x55\x55\xd4\xd7\x55\xd5\x55\x55\x55\x55\x55\x54\x57\x54\x55\x55\xd5\xd5\xd7\xd6\xd7\xd1\xd1\xd3\xd2\xd3\xd2\xd2\xd3\xd3")
+
+    # the following tests RTP header setters
+    rtp = RTP()
+    rtp.m = 1
+    rtp.pt = 3
+    rtp.seq = 1234
+    rtp.ts = 5678
+    rtp.ssrc = 0xabcdef01
+    assert (rtp.m == 1)
+    assert (rtp.pt == 3)
+    assert (rtp.seq == 1234)
+    assert (rtp.ts == 5678)
+    assert (rtp.ssrc == 0xabcdef01)
diff --git a/dpkt/sll.py b/dpkt/sll.py
index 4ebc413..5294e36 100644
--- a/dpkt/sll.py
+++ b/dpkt/sll.py
@@ -34,3 +34,16 @@
             setattr(self, self.data.__class__.__name__.lower(), self.data)
         except (KeyError, dpkt.UnpackError):
             pass
+
+def test_sll():
+    slldata = b'\x00\x00\x00\x01\x00\x06\x00\x0b\xdb\x52\x0e\x08\xf6\x7f\x08\x00\x45\x00\x00\x34\xcc\x6c\x40\x00\x40\x06\x74\x08\x82\xd9\xfa\x8e\x82\xd9\xfa\x0d'
+    slltest = SLL(slldata)
+    assert slltest.type == 0
+    assert slltest.hrd == 1
+    assert slltest.hlen == 6
+    assert slltest.hdr == b'\x00\x0b\xdb\x52\x0e\x08\xf6\x7f'
+    assert slltest.ethtype == 0x0800
+
+    # give invalid ethtype of 0x1234 to make sure error is caught
+    slldata2 = b'\x00\x00\x00\x01\x00\x06\x00\x0b\xdb\x52\x0e\x08\xf6\x7f\x12\x34\x45\x00\x00\x34\xcc\x6c\x40\x00\x40\x06\x74\x08\x82\xd9\xfa\x8e\x82\xd9\xfa\x0d'
+    slltest = SLL(slldata2)
diff --git a/dpkt/tcp.py b/dpkt/tcp.py
index 4818e8a..c051b2f 100644
--- a/dpkt/tcp.py
+++ b/dpkt/tcp.py
@@ -159,8 +159,16 @@
     opts = parse_opts(buf)
     assert opts == [None]
 
+def test_offset():
+    tcpheader = TCP(b'\x01\xbb\xc0\xd7\xb6\x56\xa8\xb9\xd1\xac\xaa\xb1\x50\x18\x40\x00\x56\xf8\x00\x00')
+    assert tcpheader.off == 5
+
+    # test setting header offset
+    tcpheader.off = 8
+    assert bytes(tcpheader) == b'\x01\xbb\xc0\xd7\xb6\x56\xa8\xb9\xd1\xac\xaa\xb1\x80\x18\x40\x00\x56\xf8\x00\x00'
 
 if __name__ == '__main__':
     # Runs all the test associated with this class/file
     test_parse_opts()
+    test_offset()
     print('Tests Successful...')