dpkt/icmp.py

# $Id: icmp.py 45 2007-08-03 00:05:22Z jon.oberheide $
# -*- coding: utf-8 -*-
"""Internet Control Message Protocol."""
from __future__ import print_function
from __future__ import absolute_import

from . import dpkt

# Types (icmp_type) and codes (icmp_code) -
# http://www.iana.org/assignments/icmp-parameters

ICMP_CODE_NONE = 0  # for types without codes
ICMP_ECHOREPLY = 0  # echo reply
ICMP_UNREACH = 3  # dest unreachable, codes:
ICMP_UNREACH_NET = 0  # bad net
ICMP_UNREACH_HOST = 1  # bad host
ICMP_UNREACH_PROTO = 2  # bad protocol
ICMP_UNREACH_PORT = 3  # bad port
ICMP_UNREACH_NEEDFRAG = 4  # IP_DF caused drop
ICMP_UNREACH_SRCFAIL = 5  # src route failed
ICMP_UNREACH_NET_UNKNOWN = 6  # unknown net
ICMP_UNREACH_HOST_UNKNOWN = 7  # unknown host
ICMP_UNREACH_ISOLATED = 8  # src host isolated
ICMP_UNREACH_NET_PROHIB = 9  # for crypto devs
ICMP_UNREACH_HOST_PROHIB = 10  # ditto
ICMP_UNREACH_TOSNET = 11  # bad tos for net
ICMP_UNREACH_TOSHOST = 12  # bad tos for host
ICMP_UNREACH_FILTER_PROHIB = 13  # prohibited access
ICMP_UNREACH_HOST_PRECEDENCE = 14  # precedence error
ICMP_UNREACH_PRECEDENCE_CUTOFF = 15  # precedence cutoff
ICMP_SRCQUENCH = 4  # packet lost, slow down
ICMP_REDIRECT = 5  # shorter route, codes:
ICMP_REDIRECT_NET = 0  # for network
ICMP_REDIRECT_HOST = 1  # for host
ICMP_REDIRECT_TOSNET = 2  # for tos and net
ICMP_REDIRECT_TOSHOST = 3  # for tos and host
ICMP_ALTHOSTADDR = 6  # alternate host address
ICMP_ECHO = 8  # echo service
ICMP_RTRADVERT = 9  # router advertise, codes:
ICMP_RTRADVERT_NORMAL = 0  # normal
ICMP_RTRADVERT_NOROUTE_COMMON = 16  # selective routing
ICMP_RTRSOLICIT = 10  # router solicitation
ICMP_TIMEXCEED = 11  # time exceeded, code:
ICMP_TIMEXCEED_INTRANS = 0  # ttl==0 in transit
ICMP_TIMEXCEED_REASS = 1  # ttl==0 in reass
ICMP_PARAMPROB = 12  # ip header bad
ICMP_PARAMPROB_ERRATPTR = 0  # req. opt. absent
ICMP_PARAMPROB_OPTABSENT = 1  # req. opt. absent
ICMP_PARAMPROB_LENGTH = 2  # bad length
ICMP_TSTAMP = 13  # timestamp request
ICMP_TSTAMPREPLY = 14  # timestamp reply
ICMP_INFO = 15  # information request
ICMP_INFOREPLY = 16  # information reply
ICMP_MASK = 17  # address mask request
ICMP_MASKREPLY = 18  # address mask reply
ICMP_TRACEROUTE = 30  # traceroute
ICMP_DATACONVERR = 31  # data conversion error
ICMP_MOBILE_REDIRECT = 32  # mobile host redirect
ICMP_IP6_WHEREAREYOU = 33  # IPv6 where-are-you
ICMP_IP6_IAMHERE = 34  # IPv6 i-am-here
ICMP_MOBILE_REG = 35  # mobile registration req
ICMP_MOBILE_REGREPLY = 36  # mobile registration reply
ICMP_DNS = 37  # domain name request
ICMP_DNSREPLY = 38  # domain name reply
ICMP_SKIP = 39  # SKIP
ICMP_PHOTURIS = 40  # Photuris
ICMP_PHOTURIS_UNKNOWN_INDEX = 0  # unknown sec index
ICMP_PHOTURIS_AUTH_FAILED = 1  # auth failed
ICMP_PHOTURIS_DECOMPRESS_FAILED = 2  # decompress failed
ICMP_PHOTURIS_DECRYPT_FAILED = 3  # decrypt failed
ICMP_PHOTURIS_NEED_AUTHN = 4  # no authentication
ICMP_PHOTURIS_NEED_AUTHZ = 5  # no authorization
ICMP_TYPE_MAX = 40


class ICMP(dpkt.Packet):
    """Internet Control Message Protocol.

    TODO: Longer class information....

    Attributes:
        __hdr__: Header fields of ICMP.
        TODO.
    """

    __hdr__ = (
        ('type', 'B', 8),
        ('code', 'B', 0),
        ('sum', 'H', 0)
    )

    class Echo(dpkt.Packet):
        __hdr__ = (('id', 'H', 0), ('seq', 'H', 0))

    class Quote(dpkt.Packet):
        __hdr__ = (('pad', 'I', 0),)

        def unpack(self, buf):
            dpkt.Packet.unpack(self, buf)
            from . import ip
            self.data = self.ip = ip.IP(self.data)

    class Unreach(Quote):
        __hdr__ = (('pad', 'H', 0), ('mtu', 'H', 0))

    class Quench(Quote):
        pass

    class Redirect(Quote):
        __hdr__ = (('gw', 'I', 0),)

    class ParamProbe(Quote):
        __hdr__ = (('ptr', 'B', 0), ('pad1', 'B', 0), ('pad2', 'H', 0))

    class TimeExceed(Quote):
        pass

    _typesw = {0: Echo, 3: Unreach, 4: Quench, 5: Redirect, 8: Echo, 11: TimeExceed}

    def unpack(self, buf):
        dpkt.Packet.unpack(self, buf)
        try:
            self.data = self._typesw[self.type](self.data)
            setattr(self, self.data.__class__.__name__.lower(), self.data)
        except (KeyError, dpkt.UnpackError):
            pass

    def __bytes__(self):
        if not self.sum:
            self.sum = dpkt.in_cksum(dpkt.Packet.__bytes__(self))
        return dpkt.Packet.__bytes__(self)


def test_icmp():
    s = (
        b'\x03\x0a\x6b\x19\x00\x00\x00\x00\x45\x00\x00\x28\x94\x1f\x00\x00\xe3\x06\x99\xb4\x23\x2b'
        b'\x24\x00\xde\x8e\x84\x42\xab\xd1\x00\x50\x00\x35\xe1\x29\x20\xd9\x00\x00\x00\x22\x9b\xf0'
        b'\xe2\x04\x65\x6b'
    )
    r = ICMP(s)
    assert bytes(r) == s

    # construction
    s = (
        b'\x00\x00\x53\x87\x00\x01\x03\xd6\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e'
        b'\x4f\x50\x51\x52\x53\x54\x55\x56\x57\x41\x42\x43\x44\x45\x46\x47\x48\x49'
    )
    p = ICMP(
        type=0,
        sum=0x5387,
        data=ICMP.Echo(
            id=1,
            seq=0x03d6,
            data=b'ABCDEFGHIJKLMNOPQRSTUVWABCDEFGHI'
        )
    )
    assert bytes(p) == s

    # test checksum
    p = ICMP(
        type=0,
        data=ICMP.Echo(
            id=1,
            seq=0x03d6,
            data=b'ABCDEFGHIJKLMNOPQRSTUVWABCDEFGHI'
        )
    )
    assert bytes(p) == s
    assert p.sum == 0x5387


def test_invalid_data():
    from binascii import unhexlify

    buf = unhexlify(
        '01'    # type (invalid entry)
        '00'    # code
        '0000'  # sum

        'abcd'  # data
    )
    icmp = ICMP(buf)

    # no additional attributes have been added due to the type being invalid
    assert dir(icmp) == dir(ICMP())