Source code for dpkt.ip6

# $Id: ip6.py 87 2013-03-05 19:41:04Z [email protected] $
# -*- coding: utf-8 -*-
"""Internet Protocol, version 6."""
from __future__ import print_function
from __future__ import absolute_import

from . import dpkt
from . import ip
from .compat import compat_ord


[docs]class IP6(dpkt.Packet): """Internet Protocol, version 6. TODO: Longer class information.... Attributes: __hdr__: Header fields of IPv6. TODO. """ __hdr__ = ( ('_v_fc_flow', 'I', 0x60000000), ('plen', 'H', 0), # payload length (not including header) ('nxt', 'B', 0), # next header protocol ('hlim', 'B', 0), # hop limit ('src', '16s', ''), ('dst', '16s', '') ) _protosw = ip.IP._protosw @property def v(self): return self._v_fc_flow >> 28 @v.setter def v(self, v): self._v_fc_flow = (self._v_fc_flow & ~0xf0000000) | (v << 28) @property def fc(self): return (self._v_fc_flow >> 20) & 0xff @fc.setter def fc(self, v): self._v_fc_flow = (self._v_fc_flow & ~0xff00000) | (v << 20) @property def flow(self): return self._v_fc_flow & 0xfffff @flow.setter def flow(self, v): self._v_fc_flow = (self._v_fc_flow & ~0xfffff) | (v & 0xfffff)
[docs] def unpack(self, buf): dpkt.Packet.unpack(self, buf) self.extension_hdrs = {} # NOTE: self.extension_hdrs is not accurate, as it doesn't support duplicate header types. # According to RFC-1883 "Each extension header should occur at most once, except for the # Destination Options header which should occur at most twice". # Secondly, the .headers_str() method attempts to pack the extension headers in order as # defined in the RFC, however it doesn't adjust the next header (nxt) pointer accordingly. # Here we introduce the new field .all_extension_headers; it allows duplicate types and # keeps the original order. self.all_extension_headers = [] if self.plen: buf = self.data[:self.plen] else: # due to jumbo payload or TSO buf = self.data next_ext_hdr = self.nxt while next_ext_hdr in ext_hdrs: ext = ext_hdrs_cls[next_ext_hdr](buf) self.extension_hdrs[next_ext_hdr] = ext self.all_extension_headers.append(ext) buf = buf[ext.length:] next_ext_hdr = getattr(ext, 'nxt', None) # set the payload protocol id if next_ext_hdr is not None: self.p = next_ext_hdr try: self.data = self._protosw[next_ext_hdr](buf) setattr(self, self.data.__class__.__name__.lower(), self.data) except (KeyError, dpkt.UnpackError): self.data = buf
[docs] def headers_str(self): # If all_extension_headers is available, return the headers as they originally appeared if self.all_extension_headers: return b''.join(bytes(ext) for ext in self.all_extension_headers) # Output extension headers in order defined in RFC1883 (except dest opts) header_str = b"" for hdr in ext_hdrs: if hdr in self.extension_hdrs: header_str += bytes(self.extension_hdrs[hdr]) return header_str
def __bytes__(self): if (self.p == 6 or self.p == 17 or self.p == 58) and not self.data.sum: # XXX - set TCP, UDP, and ICMPv6 checksums p = bytes(self.data) s = dpkt.struct.pack('>16s16sxBH', self.src, self.dst, self.nxt, len(p)) s = dpkt.in_cksum_add(0, s) s = dpkt.in_cksum_add(s, p) try: self.data.sum = dpkt.in_cksum_done(s) except AttributeError: pass return self.pack_hdr() + self.headers_str() + bytes(self.data)
[docs] @classmethod def set_proto(cls, p, pktclass): cls._protosw[p] = pktclass
[docs] @classmethod def get_proto(cls, p): return cls._protosw[p]
[docs]class IP6ExtensionHeader(dpkt.Packet): """ An extension header is very similar to a 'sub-packet'. We just want to re-use all the hdr unpacking etc. """ pass
[docs]class IP6OptsHeader(IP6ExtensionHeader): __hdr__ = ( ('nxt', 'B', 0), # next extension header protocol ('len', 'B', 0) # option data length in 8 octect units (ignoring first 8 octets) so, len 0 == 64bit header )
[docs] def unpack(self, buf): dpkt.Packet.unpack(self, buf) self.length = (self.len + 1) * 8 options = [] index = 0 while index < self.length - 2: opt_type = compat_ord(self.data[index]) # PAD1 option if opt_type == 0: index += 1 continue opt_length = compat_ord(self.data[index + 1]) if opt_type == 1: # PADN option # PADN uses opt_length bytes in total index += opt_length + 2 continue options.append( {'type': opt_type, 'opt_length': opt_length, 'data': self.data[index + 2:index + 2 + opt_length]}) # add the two chars and the option_length, to move to the next option index += opt_length + 2 self.options = options self.data = buf[2:self.length] # keep raw data with all pad options, but not the following data
[docs]class IP6HopOptsHeader(IP6OptsHeader): pass
[docs]class IP6DstOptsHeader(IP6OptsHeader): pass
[docs]class IP6RoutingHeader(IP6ExtensionHeader): __hdr__ = ( ('nxt', 'B', 0), # next extension header protocol ('len', 'B', 0), # extension data length in 8 octect units (ignoring first 8 octets) (<= 46 for type 0) ('type', 'B', 0), # routing type (currently, only 0 is used) ('segs_left', 'B', 0), # remaining segments in route, until destination (<= 23) ('rsvd_sl_bits', 'I', 0), # reserved (1 byte), strict/loose bitmap for addresses ) @property def sl_bits(self): return self.rsvd_sl_bits & 0xffffff @sl_bits.setter def sl_bits(self, v): self.rsvd_sl_bits = (self.rsvd_sl_bits & ~0xfffff) | (v & 0xfffff)
[docs] def unpack(self, buf): hdr_size = 8 addr_size = 16 dpkt.Packet.unpack(self, buf) addresses = [] num_addresses = self.len // 2 buf = buf[hdr_size:hdr_size + num_addresses * addr_size] for i in range(num_addresses): addresses.append(buf[i * addr_size: i * addr_size + addr_size]) self.data = buf self.addresses = addresses self.length = self.len * 8 + 8
[docs]class IP6FragmentHeader(IP6ExtensionHeader): __hdr__ = ( ('nxt', 'B', 0), # next extension header protocol ('resv', 'B', 0), # reserved, set to 0 ('frag_off_resv_m', 'H', 0), # frag offset (13 bits), reserved zero (2 bits), More frags flag ('id', 'I', 0) # fragments id )
[docs] def unpack(self, buf): dpkt.Packet.unpack(self, buf) self.length = self.__hdr_len__ self.data = b''
@property def frag_off(self): return self.frag_off_resv_m >> 3 @frag_off.setter def frag_off(self, v): self.frag_off_resv_m = (self.frag_off_resv_m & ~0xfff8) | (v << 3) @property def m_flag(self): return self.frag_off_resv_m & 1 @m_flag.setter def m_flag(self, v): self.frag_off_resv_m = (self.frag_off_resv_m & ~0xfffe) | v
[docs]class IP6AHHeader(IP6ExtensionHeader): __hdr__ = ( ('nxt', 'B', 0), # next extension header protocol ('len', 'B', 0), # length of header in 4 octet units (ignoring first 2 units) ('resv', 'H', 0), # reserved, 2 bytes of 0 ('spi', 'I', 0), # SPI security parameter index ('seq', 'I', 0) # sequence no. )
[docs] def unpack(self, buf): dpkt.Packet.unpack(self, buf) self.length = (self.len + 2) * 4 self.auth_data = self.data[:(self.len - 1) * 4]
[docs]class IP6ESPHeader(IP6ExtensionHeader): __hdr__ = ( ('spi', 'I', 0), ('seq', 'I', 0) )
[docs] def unpack(self, buf): dpkt.Packet.unpack(self, buf) self.length = self.__hdr_len__ + len(self.data)
ext_hdrs = [ip.IP_PROTO_HOPOPTS, ip.IP_PROTO_ROUTING, ip.IP_PROTO_FRAGMENT, ip.IP_PROTO_AH, ip.IP_PROTO_ESP, ip.IP_PROTO_DSTOPTS] ext_hdrs_cls = {ip.IP_PROTO_HOPOPTS: IP6HopOptsHeader, ip.IP_PROTO_ROUTING: IP6RoutingHeader, ip.IP_PROTO_FRAGMENT: IP6FragmentHeader, ip.IP_PROTO_ESP: IP6ESPHeader, ip.IP_PROTO_AH: IP6AHHeader, ip.IP_PROTO_DSTOPTS: IP6DstOptsHeader} # Unit tests
[docs]def test_ipg(): s = (b'\x60\x00\x00\x00\x00\x28\x06\x40\xfe\x80\x00\x00\x00\x00\x00\x00\x02\x11\x24\xff\xfe\x8c' b'\x11\xde\xfe\x80\x00\x00\x00\x00\x00\x00\x02\xb0\xd0\xff\xfe\xe1\x80\x72\xcd\xca\x00\x16' b'\x04\x84\x46\xd5\x00\x00\x00\x00\xa0\x02\xff\xff\xf8\x09\x00\x00\x02\x04\x05\xa0\x01\x03' b'\x03\x00\x01\x01\x08\x0a\x7d\x18\x35\x3f\x00\x00\x00\x00') _ip = IP6(s) # basic properties assert _ip.v == 6 assert _ip.fc == 0 assert _ip.flow == 0 _ip.data.sum = 0 s2 = bytes(_ip) assert s == s2
[docs]def test_ip6_routing_header(): s = (b'\x60\x00\x00\x00\x00\x3c\x2b\x40\x20\x48\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' b'\xde\xca\x20\x47\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xca\xfe\x06\x04\x00\x02' b'\x00\x00\x00\x00\x20\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xde\xca\x20\x22' b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xde\xca\x00\x14\x00\x50\x00\x00\x00\x00' b'\x00\x00\x00\x00\x50\x02\x20\x00\x91\x7f\x00\x00') _ip = IP6(s) s2 = bytes(_ip) # 43 is Routing header id assert len(_ip.extension_hdrs[43].addresses) == 2 assert _ip.tcp assert s == s2
[docs]def test_ip6_fragment_header(): s = b'\x06\xee\xff\xfb\x00\x00\xff\xff' fh = IP6FragmentHeader(s) # s2 = str(fh) variable 's2' is not used assert fh.nxt == 6 assert fh.id == 65535 assert fh.frag_off == 8191 assert fh.m_flag == 1 assert bytes(fh) == s # IP6 with fragment header s = (b'\x60\x00\x00\x00\x00\x10\x2c\x00\x02\x22\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' b'\x00\x02\x03\x33\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03\x29\x00\x00\x01' b'\x00\x00\x00\x00\x60\x00\x00\x00\x00\x10\x2c\x00') _ip = IP6(s) assert bytes(_ip) == s
[docs]def test_ip6_options_header(): s = (b'\x3b\x04\x01\x02\x00\x00\xc9\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' b'\x00\x00\x01\x00\xc2\x04\x00\x00\x00\x00\x05\x02\x00\x00\x01\x02\x00\x00') options = IP6OptsHeader(s).options assert len(options) == 3 assert bytes(IP6OptsHeader(s)) == s
[docs]def test_ip6_ah_header(): s = b'\x3b\x04\x00\x00\x02\x02\x02\x02\x01\x01\x01\x01\x78\x78\x78\x78\x78\x78\x78\x78' ah = IP6AHHeader(s) assert ah.length == 24 assert ah.auth_data == b'xxxxxxxx' assert ah.spi == 0x2020202 assert ah.seq == 0x1010101 assert bytes(ah) == s
[docs]def test_ip6_esp_header(): s = (b'\x00\x00\x01\x00\x00\x00\x00\x44\xe2\x4f\x9e\x68\xf3\xcd\xb1\x5f\x61\x65\x42\x8b\x78\x0b' b'\x4a\xfd\x13\xf0\x15\x98\xf5\x55\x16\xa8\x12\xb3\xb8\x4d\xbc\x16\xb2\x14\xbe\x3d\xf9\x96' b'\xd4\xa0\x39\x1f\x85\x74\x25\x81\x83\xa6\x0d\x99\xb6\xba\xa3\xcc\xb6\xe0\x9a\x78\xee\xf2' b'\xaf\x9a') esp = IP6ESPHeader(s) assert esp.length == 68 assert esp.spi == 256 assert bytes(esp) == s
[docs]def test_ip6_extension_headers(): p = (b'\x60\x00\x00\x00\x00\x3c\x2b\x40\x20\x48\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' b'\xde\xca\x20\x47\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xca\xfe\x06\x04\x00\x02' b'\x00\x00\x00\x00\x20\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xde\xca\x20\x22' b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xde\xca\x00\x14\x00\x50\x00\x00\x00\x00' b'\x00\x00\x00\x00\x50\x02\x20\x00\x91\x7f\x00\x00') _ip = IP6(p) o = (b'\x3b\x04\x01\x02\x00\x00\xc9\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' b'\x00\x00\x01\x00\xc2\x04\x00\x00\x00\x00\x05\x02\x00\x00\x01\x02\x00\x00') _ip.extension_hdrs[0] = IP6HopOptsHeader(o) fh = b'\x06\xee\xff\xfb\x00\x00\xff\xff' _ip.extension_hdrs[44] = IP6FragmentHeader(fh) ah = b'\x3b\x04\x00\x00\x02\x02\x02\x02\x01\x01\x01\x01\x78\x78\x78\x78\x78\x78\x78\x78' _ip.extension_hdrs[51] = IP6AHHeader(ah) do = b'\x3b\x02\x01\x02\x00\x00\xc9\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' _ip.extension_hdrs[60] = IP6DstOptsHeader(do) assert len(_ip.extension_hdrs) == 5
[docs]def test_ip6_all_extension_headers(): # https://github.com/kbandla/dpkt/pull/403 s = (b'\x60\x00\x00\x00\x00\x47\x3c\x40\xfe\xd0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01' b'\x00\x02\xfe\xd0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x01\x3c\x00\x01\x04' b'\x00\x00\x00\x00\x3c\x00\x01\x04\x00\x00\x00\x00\x2c\x00\x01\x04\x00\x00\x00\x00\x2c\x00' b'\x00\x00\x00\x00\x00\x00\x3c\x00\x00\x00\x00\x00\x00\x00\x2c\x00\x01\x04\x00\x00\x00\x00' b'\x3a\x00\x00\x00\x00\x00\x00\x00\x80\x00\xd8\xe5\x0c\x1a\x00\x00\x50\x61\x79\x4c\x6f\x61' b'\x64') _ip = IP6(s) assert _ip.p == 58 # ICMPv6 hdrs = _ip.all_extension_headers assert len(hdrs) == 7 assert isinstance(hdrs[0], IP6DstOptsHeader) assert isinstance(hdrs[3], IP6FragmentHeader) assert isinstance(hdrs[5], IP6DstOptsHeader) assert bytes(_ip) == s
if __name__ == '__main__': test_ipg() test_ip6_routing_header() test_ip6_fragment_header() test_ip6_options_header() test_ip6_ah_header() test_ip6_esp_header() test_ip6_extension_headers() test_ip6_all_extension_headers() print('Tests Successful...')