# SPDX-License-Identifier: GPL-2.0-only
# This file is part of Scapy
# See https://scapy.net/ for more information
# Copyright (C) Philippe Biondi <phil@secdev.org>

"""
IPv4 (Internet Protocol v4).
"""

import time
import struct
import re
import random
import select
import socket
from collections import defaultdict

from scapy.utils import checksum, do_graph, incremental_label, \
    linehexdump, strxor, whois, colgen
from scapy.ansmachine import AnsweringMachine
from scapy.base_classes import Gen, Net, _ScopedIP
from scapy.consts import OPENBSD
from scapy.data import (
    ETH_P_IP,
    ETH_P_ALL,
    DLT_RAW,
    DLT_RAW_ALT,
    DLT_IPV4,
    IP_PROTOS,
    TCP_SERVICES,
    UDP_SERVICES,
)
from scapy.layers.l2 import (
    CookedLinux,
    Dot3,
    Ether,
    GRE,
    Loopback,
    SNAP,
    arpcachepoison,
    getmacbyip,
)
from scapy.compat import raw, chb, orb, bytes_encode, Optional
from scapy.config import conf
from scapy.fields import (
    BitEnumField,
    BitField,
    ByteEnumField,
    ByteField,
    ConditionalField,
    DestField,
    Emph,
    FieldLenField,
    FieldListField,
    FlagsField,
    IPField,
    IP6Field,
    IntField,
    MayEnd,
    MultiEnumField,
    MultipleTypeField,
    PacketField,
    PacketListField,
    ShortEnumField,
    ShortField,
    SourceIPField,
    StrField,
    StrFixedLenField,
    StrLenField,
    TrailerField,
    XByteField,
    XShortField,
)
from scapy.packet import Packet, bind_layers, bind_bottom_up, NoPayload
from scapy.volatile import RandShort, RandInt, RandBin, RandNum, VolatileValue
from scapy.sendrecv import sr, sr1
from scapy.plist import _PacketList, PacketList, SndRcvList
from scapy.automaton import Automaton, ATMT
from scapy.error import log_runtime, warning
from scapy.pton_ntop import inet_pton

import scapy.as_resolvers

####################
#  IP Tools class  #
####################


class IPTools(object):
    """Add more powers to a class with an "src" attribute."""
    __slots__ = []

    def whois(self):
        """whois the source and print the output"""
        print(whois(self.src).decode("utf8", "ignore"))

    def _ttl(self):
        """Returns ttl or hlim, depending on the IP version"""
        return self.hlim if isinstance(self, scapy.layers.inet6.IPv6) else self.ttl  # noqa: E501

    def ottl(self):
        t = sorted([32, 64, 128, 255] + [self._ttl()])
        return t[t.index(self._ttl()) + 1]

    def hops(self):
        return self.ottl() - self._ttl()


_ip_options_names = {0: "end_of_list",
                     1: "nop",
                     2: "security",
                     3: "loose_source_route",
                     4: "timestamp",
                     5: "extended_security",
                     6: "commercial_security",
                     7: "record_route",
                     8: "stream_id",
                     9: "strict_source_route",
                     10: "experimental_measurement",
                     11: "mtu_probe",
                     12: "mtu_reply",
                     13: "flow_control",
                     14: "access_control",
                     15: "encode",
                     16: "imi_traffic_descriptor",
                     17: "extended_IP",
                     18: "traceroute",
                     19: "address_extension",
                     20: "router_alert",
                     21: "selective_directed_broadcast_mode",
                     23: "dynamic_packet_state",
                     24: "upstream_multicast_packet",
                     25: "quick_start",
                     30: "rfc4727_experiment",
                     }


class _IPOption_HDR(Packet):
    fields_desc = [BitField("copy_flag", 0, 1),
                   BitEnumField("optclass", 0, 2, {0: "control", 2: "debug"}),
                   BitEnumField("option", 0, 5, _ip_options_names)]


class IPOption(Packet):
    name = "IP Option"
    fields_desc = [_IPOption_HDR,
                   FieldLenField("length", None, fmt="B",  # Only option 0 and 1 have no length and value  # noqa: E501
                                 length_of="value", adjust=lambda pkt, l:l + 2),  # noqa: E501
                   StrLenField("value", "", length_from=lambda pkt:pkt.length - 2)]  # noqa: E501

    def extract_padding(self, p):
        return b"", p

    registered_ip_options = {}

    @classmethod
    def register_variant(cls):
        cls.registered_ip_options[cls.option.default] = cls

    @classmethod
    def dispatch_hook(cls, pkt=None, *args, **kargs):
        if pkt:
            opt = orb(pkt[0]) & 0x1f
            if opt in cls.registered_ip_options:
                return cls.registered_ip_options[opt]
        return cls


class IPOption_EOL(IPOption):
    name = "IP Option End of Options List"
    option = 0
    fields_desc = [_IPOption_HDR]


class IPOption_NOP(IPOption):
    name = "IP Option No Operation"
    option = 1
    fields_desc = [_IPOption_HDR]


class IPOption_Security(IPOption):
    name = "IP Option Security"
    copy_flag = 1
    option = 2
    fields_desc = [_IPOption_HDR,
                   ByteField("length", 11),
                   ShortField("security", 0),
                   ShortField("compartment", 0),
                   ShortField("handling_restrictions", 0),
                   StrFixedLenField("transmission_control_code", "xxx", 3),
                   ]


class IPOption_RR(IPOption):
    name = "IP Option Record Route"
    option = 7
    fields_desc = [_IPOption_HDR,
                   FieldLenField("length", None, fmt="B",
                                 length_of="routers", adjust=lambda pkt, l:l + 3),  # noqa: E501
                   ByteField("pointer", 4),  # 4 is first IP
                   FieldListField("routers", [], IPField("", "0.0.0.0"),
                                  length_from=lambda pkt:pkt.length - 3)
                   ]

    def get_current_router(self):
        return self.routers[self.pointer // 4 - 1]


class IPOption_LSRR(IPOption_RR):
    name = "IP Option Loose Source and Record Route"
    copy_flag = 1
    option = 3


class IPOption_SSRR(IPOption_RR):
    name = "IP Option Strict Source and Record Route"
    copy_flag = 1
    option = 9


class IPOption_Stream_Id(IPOption):
    name = "IP Option Stream ID"
    copy_flag = 1
    option = 8
    fields_desc = [_IPOption_HDR,
                   ByteField("length", 4),
                   ShortField("security", 0), ]


class IPOption_MTU_Probe(IPOption):
    name = "IP Option MTU Probe"
    option = 11
    fields_desc = [_IPOption_HDR,
                   ByteField("length", 4),
                   ShortField("mtu", 0), ]


class IPOption_MTU_Reply(IPOption_MTU_Probe):
    name = "IP Option MTU Reply"
    option = 12


class IPOption_Traceroute(IPOption):
    name = "IP Option Traceroute"
    option = 18
    fields_desc = [_IPOption_HDR,
                   ByteField("length", 12),
                   ShortField("id", 0),
                   ShortField("outbound_hops", 0),
                   ShortField("return_hops", 0),
                   IPField("originator_ip", "0.0.0.0")]


class IPOption_Timestamp(IPOption):
    name = "IP Option Timestamp"
    optclass = 2
    option = 4
    fields_desc = [_IPOption_HDR,
                   ByteField("length", None),
                   ByteField("pointer", 9),
                   BitField("oflw", 0, 4),
                   BitEnumField("flg", 1, 4,
                                {0: "timestamp_only",
                                 1: "timestamp_and_ip_addr",
                                 3: "prespecified_ip_addr"}),
                   ConditionalField(IPField("internet_address", "0.0.0.0"),
                                    lambda pkt: pkt.flg != 0),
                   IntField('timestamp', 0)]

    def post_build(self, p, pay):
        if self.length is None:
            p = p[:1] + struct.pack("!B", len(p)) + p[2:]
        return p + pay


class IPOption_Address_Extension(IPOption):
    name = "IP Option Address Extension"
    copy_flag = 1
    option = 19
    fields_desc = [_IPOption_HDR,
                   ByteField("length", 10),
                   IPField("src_ext", "0.0.0.0"),
                   IPField("dst_ext", "0.0.0.0")]


class IPOption_Router_Alert(IPOption):
    name = "IP Option Router Alert"
    copy_flag = 1
    option = 20
    fields_desc = [_IPOption_HDR,
                   ByteField("length", 4),
                   ShortEnumField("alert", 0, {0: "router_shall_examine_packet"}), ]  # noqa: E501


class IPOption_SDBM(IPOption):
    name = "IP Option Selective Directed Broadcast Mode"
    copy_flag = 1
    option = 21
    fields_desc = [_IPOption_HDR,
                   FieldLenField("length", None, fmt="B",
                                 length_of="addresses", adjust=lambda pkt, l:l + 2),  # noqa: E501
                   FieldListField("addresses", [], IPField("", "0.0.0.0"),
                                  length_from=lambda pkt:pkt.length - 2)
                   ]


TCPOptions = (
    {0: ("EOL", None),
     1: ("NOP", None),
     2: ("MSS", "!H"),
     3: ("WScale", "!B"),
     4: ("SAckOK", None),
     5: ("SAck", "!"),
     8: ("Timestamp", "!II"),
     14: ("AltChkSum", "!BH"),
     15: ("AltChkSumOpt", None),
     19: ("MD5", "16s"),
     25: ("Mood", "!p"),
     28: ("UTO", "!H"),
     29: ("AO", None),
     34: ("TFO", "!II"),
     # RFC 3692
     # 253: ("Experiment", "!HHHH"),
     # 254: ("Experiment", "!HHHH"),
     },
    {"EOL": 0,
     "NOP": 1,
     "MSS": 2,
     "WScale": 3,
     "SAckOK": 4,
     "SAck": 5,
     "Timestamp": 8,
     "AltChkSum": 14,
     "AltChkSumOpt": 15,
     "MD5": 19,
     "Mood": 25,
     "UTO": 28,
     "AO": 29,
     "TFO": 34,
     })


class TCPAOValue(Packet):
    """Value of TCP-AO option"""
    fields_desc = [
        ByteField("keyid", None),
        ByteField("rnextkeyid", None),
        StrLenField("mac", "", length_from=lambda p:len(p.original) - 2),
    ]


def get_tcpao(tcphdr):
    # type: (TCP) -> Optional[TCPAOValue]
    """Get the TCP-AO option from the header"""
    for optid, optval in tcphdr.options:
        if optid == 'AO':
            return optval
    return None


class RandTCPOptions(VolatileValue):
    def __init__(self, size=None):
        if size is None:
            size = RandNum(1, 5)
        self.size = size

    def _fix(self):
        # Pseudo-Random amount of options
        # Random ("NAME", fmt)
        rand_patterns = [
            random.choice(list(
                (opt, fmt) for opt, fmt in TCPOptions[0].values()
                if opt != 'EOL'
            ))
            for _ in range(self.size)
        ]
        rand_vals = []
        for oname, fmt in rand_patterns:
            if fmt is None:
                rand_vals.append((oname, b''))
            else:
                # Process the fmt arguments 1 by 1
                structs = re.findall(r"!?([bBhHiIlLqQfdpP]|\d+[spx])", fmt)
                rval = []
                for stru in structs:
                    stru = "!" + stru
                    if "s" in stru or "p" in stru:  # str / chr
                        v = bytes(RandBin(struct.calcsize(stru)))
                    else:  # int
                        _size = struct.calcsize(stru)
                        v = random.randint(0, 2 ** (8 * _size) - 1)
                    rval.append(v)
                rand_vals.append((oname, tuple(rval)))
        return rand_vals

    def __bytes__(self):
        return TCPOptionsField.i2m(None, None, self._fix())


class TCPOptionsField(StrField):
    islist = 1

    def getfield(self, pkt, s):
        opsz = (pkt.dataofs - 5) * 4
        if opsz < 0:
            log_runtime.info(
                "bad dataofs (%i). Assuming dataofs=5", pkt.dataofs
            )
            opsz = 0
        return s[opsz:], self.m2i(pkt, s[:opsz])

    def m2i(self, pkt, x):
        opt = []
        while x:
            onum = orb(x[0])
            if onum == 0:
                opt.append(("EOL", None))
                break
            if onum == 1:
                opt.append(("NOP", None))
                x = x[1:]
                continue
            try:
                olen = orb(x[1])
            except IndexError:
                olen = 0
            if olen < 2:
                log_runtime.info(
                    "Malformed TCP option (announced length is %i)", olen
                )
                olen = 2
            oval = x[2:olen]
            if onum in TCPOptions[0]:
                oname, ofmt = TCPOptions[0][onum]
                if onum == 5:  # SAck
                    ofmt += "%iI" % (len(oval) // 4)
                if onum == 29:  # AO
                    oval = TCPAOValue(oval)
                if ofmt and struct.calcsize(ofmt) == len(oval):
                    oval = struct.unpack(ofmt, oval)
                    if len(oval) == 1:
                        oval = oval[0]
                opt.append((oname, oval))
            else:
                opt.append((onum, oval))
            x = x[olen:]
        return opt

    def i2h(self, pkt, x):
        if not x:
            return []
        return x

    def i2m(self, pkt, x):
        opt = b""
        for oname, oval in x:
            # We check for a (0, b'') or (1, b'') option first
            oname = {0: "EOL", 1: "NOP"}.get(oname, oname)
            if isinstance(oname, str):
                if oname == "NOP":
                    opt += b"\x01"
                    continue
                elif oname == "EOL":
                    opt += b"\x00"
                    continue
                elif oname in TCPOptions[1]:
                    onum = TCPOptions[1][oname]
                    ofmt = TCPOptions[0][onum][1]
                    if onum == 5:  # SAck
                        ofmt += "%iI" % len(oval)
                    _test_isinstance = not isinstance(oval, (bytes, str))
                    if ofmt is not None and (_test_isinstance or "s" in ofmt):
                        if not isinstance(oval, tuple):
                            oval = (oval,)
                        oval = struct.pack(ofmt, *oval)
                    if onum == 29:  # AO
                        oval = bytes(oval)
                else:
                    warning("Option [%s] unknown. Skipped.", oname)
                    continue
            else:
                onum = oname
                if not isinstance(onum, int):
                    warning("Invalid option number [%i]" % onum)
                    continue
                if not isinstance(oval, (bytes, str)):
                    warning("Option [%i] is not bytes." % onum)
                    continue
            if isinstance(oval, str):
                oval = bytes_encode(oval)
            opt += chb(onum) + chb(2 + len(oval)) + oval
        return opt + b"\x00" * (3 - ((len(opt) + 3) % 4))  # Padding

    def randval(self):
        return RandTCPOptions()


class ICMPTimeStampField(IntField):
    re_hmsm = re.compile("([0-2]?[0-9])[Hh:](([0-5]?[0-9])([Mm:]([0-5]?[0-9])([sS:.]([0-9]{0,3}))?)?)?$")  # noqa: E501

    def i2repr(self, pkt, val):
        if val is None:
            return "--"
        else:
            sec, milli = divmod(val, 1000)
            min, sec = divmod(sec, 60)
            hour, min = divmod(min, 60)
            return "%d:%d:%d.%d" % (hour, min, sec, int(milli))

    def any2i(self, pkt, val):
        if isinstance(val, str):
            hmsms = self.re_hmsm.match(val)
            if hmsms:
                h, _, m, _, s, _, ms = hmsms.groups()
                ms = int(((ms or "") + "000")[:3])
                val = ((int(h) * 60 + int(m or 0)) * 60 + int(s or 0)) * 1000 + ms  # noqa: E501
            else:
                val = 0
        elif val is None:
            val = int((time.time() % (24 * 60 * 60)) * 1000)
        return val


class DestIPField(IPField, DestField):
    bindings = {}

    def __init__(self, name, default):
        IPField.__init__(self, name, None)
        DestField.__init__(self, name, default)

    def i2m(self, pkt, x):
        if x is None:
            x = self.dst_from_pkt(pkt)
        return IPField.i2m(self, pkt, x)

    def i2h(self, pkt, x):
        if x is None:
            x = self.dst_from_pkt(pkt)
        return IPField.i2h(self, pkt, x)


class IP(Packet, IPTools):
    name = "IP"
    fields_desc = [BitField("version", 4, 4),
                   BitField("ihl", None, 4),
                   XByteField("tos", 0),
                   ShortField("len", None),
                   ShortField("id", 1),
                   FlagsField("flags", 0, 3, ["MF", "DF", "evil"]),
                   BitField("frag", 0, 13),
                   ByteField("ttl", 64),
                   ByteEnumField("proto", 0, IP_PROTOS),
                   XShortField("chksum", None),
                   # IPField("src", "127.0.0.1"),
                   Emph(SourceIPField("src")),
                   Emph(DestIPField("dst", "127.0.0.1")),
                   PacketListField("options", [], IPOption, length_from=lambda p:p.ihl * 4 - 20)]  # noqa: E501

    def post_build(self, p, pay):
        ihl = self.ihl
        p += b"\0" * ((-len(p)) % 4)  # pad IP options if needed
        if ihl is None:
            ihl = len(p) // 4
            p = chb(((self.version & 0xf) << 4) | ihl & 0x0f) + p[1:]
        if self.len is None:
            tmp_len = len(p) + len(pay)
            p = p[:2] + struct.pack("!H", tmp_len) + p[4:]
        if self.chksum is None:
            ck = checksum(p)
            p = p[:10] + chb(ck >> 8) + chb(ck & 0xff) + p[12:]
        return p + pay

    def extract_padding(self, s):
        tmp_len = self.len - (self.ihl << 2)
        if tmp_len < 0:
            return s, b""
        return s[:tmp_len], s[tmp_len:]

    def route(self):
        dst = self.dst
        scope = None
        if isinstance(dst, (Net, _ScopedIP)):
            scope = dst.scope
        if isinstance(dst, (Gen, list)):
            dst = next(iter(dst))
        if conf.route is None:
            # unused import, only to initialize conf.route
            import scapy.route  # noqa: F401
        return conf.route.route(dst, dev=scope)

    def hashret(self):
        if ((self.proto == socket.IPPROTO_ICMP) and
            (isinstance(self.payload, ICMP)) and
                (self.payload.type in [3, 4, 5, 11, 12])):
            return self.payload.payload.hashret()
        if not conf.checkIPinIP and self.proto in [4, 41]:  # IP, IPv6
            return self.payload.hashret()
        if self.dst == "224.0.0.251":  # mDNS
            return struct.pack("B", self.proto) + self.payload.hashret()
        if conf.checkIPsrc and conf.checkIPaddr:
            return (strxor(inet_pton(socket.AF_INET, self.src),
                           inet_pton(socket.AF_INET, self.dst)) +
                    struct.pack("B", self.proto) + self.payload.hashret())
        return struct.pack("B", self.proto) + self.payload.hashret()

    def answers(self, other):
        if not conf.checkIPinIP:  # skip IP in IP and IPv6 in IP
            if self.proto in [4, 41]:
                return self.payload.answers(other)
            if isinstance(other, IP) and other.proto in [4, 41]:
                return self.answers(other.payload)
            if conf.ipv6_enabled \
               and isinstance(other, scapy.layers.inet6.IPv6) \
               and other.nh in [4, 41]:
                return self.answers(other.payload)
        if not isinstance(other, IP):
            return 0
        if conf.checkIPaddr:
            if other.dst == "224.0.0.251" and self.dst == "224.0.0.251":  # mDNS  # noqa: E501
                return self.payload.answers(other.payload)
            elif (self.dst != other.src):
                return 0
        if ((self.proto == socket.IPPROTO_ICMP) and
            (isinstance(self.payload, ICMP)) and
                (self.payload.type in [3, 4, 5, 11, 12])):
            # ICMP error message
            return self.payload.payload.answers(other)

        else:
            if ((conf.checkIPaddr and (self.src != other.dst)) or
                    (self.proto != other.proto)):
                return 0
            return self.payload.answers(other.payload)

    def mysummary(self):
        s = self.sprintf("%IP.src% > %IP.dst% %IP.proto%")
        if self.frag:
            s += " frag:%i" % self.frag
        return s

    def fragment(self, fragsize=1480):
        """Fragment IP datagrams"""
        return fragment(self, fragsize=fragsize)


def in4_pseudoheader(proto, u, plen):
    # type: (int, IP, int) -> bytes
    """IPv4 Pseudo Header as defined in RFC793 as bytes

    :param proto: value of upper layer protocol
    :param u: IP layer instance
    :param plen: the length of the upper layer and payload
    """
    u = u.copy()
    if u.len is not None:
        if u.ihl is None:
            olen = sum(len(x) for x in u.options)
            ihl = 5 + olen // 4 + (1 if olen % 4 else 0)
        else:
            ihl = u.ihl
        ln = max(u.len - 4 * ihl, 0)
    else:
        ln = plen

    # Filter out IPOption_LSRR and IPOption_SSRR
    sr_options = [opt for opt in u.options if isinstance(opt, IPOption_LSRR) or
                  isinstance(opt, IPOption_SSRR)]
    len_sr_options = len(sr_options)
    if len_sr_options == 1 and len(sr_options[0].routers):
        # The checksum must be computed using the final
        # destination address
        u.dst = sr_options[0].routers[-1]
    elif len_sr_options > 1:
        message = "Found %d Source Routing Options! "
        message += "Falling back to IP.dst for checksum computation."
        warning(message, len_sr_options)

    return struct.pack("!4s4sHH",
                       inet_pton(socket.AF_INET, u.src),
                       inet_pton(socket.AF_INET, u.dst),
                       proto,
                       ln)


def in4_chksum(proto, u, p):
    # type: (int, IP, bytes) -> int
    """IPv4 Pseudo Header checksum as defined in RFC793

    :param proto: value of upper layer protocol
    :param u: upper layer instance
    :param p: the payload of the upper layer provided as a string
    """
    if not isinstance(u, IP):
        warning("No IP underlayer to compute checksum. Leaving null.")
        return 0
    psdhdr = in4_pseudoheader(proto, u, len(p))
    return checksum(psdhdr + p)


def _is_ipv6_layer(p):
    # type: (Packet) -> bytes
    return (isinstance(p, scapy.layers.inet6.IPv6) or
            isinstance(p, scapy.layers.inet6._IPv6ExtHdr))


def tcp_pseudoheader(tcp):
    # type: (TCP) -> bytes
    """Pseudoheader of a TCP packet as bytes

    Requires underlayer to be either IP or IPv6
    """
    if isinstance(tcp.underlayer, IP):
        plen = len(bytes(tcp))
        return in4_pseudoheader(socket.IPPROTO_TCP, tcp.underlayer, plen)
    elif conf.ipv6_enabled and _is_ipv6_layer(tcp.underlayer):
        plen = len(bytes(tcp))
        return raw(scapy.layers.inet6.in6_pseudoheader(
            socket.IPPROTO_TCP, tcp.underlayer, plen))
    else:
        raise ValueError("TCP packet does not have IP or IPv6 underlayer")


def calc_tcp_md5_hash(tcp, key):
    # type: (TCP, bytes) -> bytes
    """Calculate TCP-MD5 hash from packet and return a 16-byte string"""
    import hashlib

    h = hashlib.md5()  # nosec
    tcp_bytes = bytes(tcp)
    h.update(tcp_pseudoheader(tcp))
    h.update(tcp_bytes[:16])
    h.update(b"\x00\x00")
    h.update(tcp_bytes[18:])
    h.update(key)

    return h.digest()


def sign_tcp_md5(tcp, key):
    # type: (TCP, bytes) -> None
    """Append TCP-MD5 signature to tcp packet"""
    sig = calc_tcp_md5_hash(tcp, key)
    tcp.options = tcp.options + [('MD5', sig)]


class TCP(Packet):
    name = "TCP"
    fields_desc = [ShortEnumField("sport", 20, TCP_SERVICES),
                   ShortEnumField("dport", 80, TCP_SERVICES),
                   IntField("seq", 0),
                   IntField("ack", 0),
                   BitField("dataofs", None, 4),
                   BitField("reserved", 0, 3),
                   FlagsField("flags", 0x2, 9, "FSRPAUECN"),
                   ShortField("window", 8192),
                   XShortField("chksum", None),
                   ShortField("urgptr", 0),
                   TCPOptionsField("options", "")]

    def post_build(self, p, pay):
        p += pay
        dataofs = self.dataofs
        if dataofs is None:
            opt_len = len(self.get_field("options").i2m(self, self.options))
            dataofs = 5 + ((opt_len + 3) // 4)
            dataofs = (dataofs << 4) | orb(p[12]) & 0x0f
            p = p[:12] + chb(dataofs & 0xff) + p[13:]
        if self.chksum is None:
            if isinstance(self.underlayer, IP):
                ck = in4_chksum(socket.IPPROTO_TCP, self.underlayer, p)
                p = p[:16] + struct.pack("!H", ck) + p[18:]
            elif conf.ipv6_enabled and isinstance(self.underlayer, scapy.layers.inet6.IPv6) or isinstance(self.underlayer, scapy.layers.inet6._IPv6ExtHdr):  # noqa: E501
                ck = scapy.layers.inet6.in6_chksum(socket.IPPROTO_TCP, self.underlayer, p)  # noqa: E501
                p = p[:16] + struct.pack("!H", ck) + p[18:]
            else:
                log_runtime.info(
                    "No IP underlayer to compute checksum. Leaving null."
                )
        return p

    def hashret(self):
        if conf.checkIPsrc:
            return struct.pack("H", self.sport ^ self.dport) + self.payload.hashret()  # noqa: E501
        else:
            return self.payload.hashret()

    def answers(self, other):
        if not isinstance(other, TCP):
            return 0
        # RST packets don't get answers
        if other.flags.R:
            return 0
        # We do not support the four-way handshakes with the SYN+ACK
        # answer split in two packets (one ACK and one SYN): in that
        # case the ACK will be seen as an answer, but not the SYN.
        if self.flags.S:
            # SYN packets without ACK are not answers
            if not self.flags.A:
                return 0
            # SYN+ACK packets answer SYN packets
            if not other.flags.S:
                return 0
        if conf.checkIPsrc:
            if not ((self.sport == other.dport) and
                    (self.dport == other.sport)):
                return 0
        # Do not check ack value for SYN packets without ACK
        if not (other.flags.S and not other.flags.A) \
           and abs(other.ack - self.seq) > 2:
            return 0
        # Do not check ack value for RST packets without ACK
        if self.flags.R and not self.flags.A:
            return 1
        if abs(other.seq - self.ack) > 2 + len(other.payload):
            return 0
        return 1

    def mysummary(self):
        if isinstance(self.underlayer, IP):
            return self.underlayer.sprintf("TCP %IP.src%:%TCP.sport% > %IP.dst%:%TCP.dport% %TCP.flags%")  # noqa: E501
        elif conf.ipv6_enabled and isinstance(self.underlayer, scapy.layers.inet6.IPv6):  # noqa: E501
            return self.underlayer.sprintf("TCP %IPv6.src%:%TCP.sport% > %IPv6.dst%:%TCP.dport% %TCP.flags%")  # noqa: E501
        else:
            return self.sprintf("TCP %TCP.sport% > %TCP.dport% %TCP.flags%")


class UDP(Packet):
    name = "UDP"
    fields_desc = [ShortEnumField("sport", 53, UDP_SERVICES),
                   ShortEnumField("dport", 53, UDP_SERVICES),
                   ShortField("len", None),
                   XShortField("chksum", None), ]

    def post_build(self, p, pay):
        p += pay
        tmp_len = self.len
        if tmp_len is None:
            tmp_len = len(p)
            p = p[:4] + struct.pack("!H", tmp_len) + p[6:]
        if self.chksum is None:
            if isinstance(self.underlayer, IP):
                ck = in4_chksum(socket.IPPROTO_UDP, self.underlayer, p)
                # According to RFC768 if the result checksum is 0, it should be set to 0xFFFF  # noqa: E501
                if ck == 0:
                    ck = 0xFFFF
                p = p[:6] + struct.pack("!H", ck) + p[8:]
            elif isinstance(self.underlayer, scapy.layers.inet6.IPv6) or isinstance(self.underlayer, scapy.layers.inet6._IPv6ExtHdr):  # noqa: E501
                ck = scapy.layers.inet6.in6_chksum(socket.IPPROTO_UDP, self.underlayer, p)  # noqa: E501
                # According to RFC2460 if the result checksum is 0, it should be set to 0xFFFF  # noqa: E501
                if ck == 0:
                    ck = 0xFFFF
                p = p[:6] + struct.pack("!H", ck) + p[8:]
            else:
                log_runtime.info(
                    "No IP underlayer to compute checksum. Leaving null."
                )
        return p

    def extract_padding(self, s):
        tmp_len = self.len - 8
        return s[:tmp_len], s[tmp_len:]

    def hashret(self):
        return self.payload.hashret()

    def answers(self, other):
        if not isinstance(other, UDP):
            return 0
        if conf.checkIPsrc:
            if self.dport != other.sport:
                return 0
        return self.payload.answers(other.payload)

    def mysummary(self):
        if isinstance(self.underlayer, IP):
            return self.underlayer.sprintf("UDP %IP.src%:%UDP.sport% > %IP.dst%:%UDP.dport%")  # noqa: E501
        elif isinstance(self.underlayer, scapy.layers.inet6.IPv6):
            return self.underlayer.sprintf("UDP %IPv6.src%:%UDP.sport% > %IPv6.dst%:%UDP.dport%")  # noqa: E501
        else:
            return self.sprintf("UDP %UDP.sport% > %UDP.dport%")


# RFC 4884 ICMP extensions
_ICMP_classnums = {
    # https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-ext-classes
    1: "MPLS",
    2: "Interface Information",
    3: "Interface Identification",
    4: "Extended Information",
}


class ICMPExtension_Object(Packet):
    name = "ICMP Extension Object"
    show_indent = 0
    fields_desc = [
        ShortField("len", None),
        ByteEnumField("classnum", 0, _ICMP_classnums),
        ByteField("classtype", 0),
    ]

    def post_build(self, p, pay):
        if self.len is None:
            tmp_len = len(p) + len(pay)
            p = struct.pack("!H", tmp_len) + p[2:]
        return p + pay

    registered_icmp_exts = {}

    @classmethod
    def register_variant(cls):
        cls.registered_icmp_exts[cls.classnum.default] = cls

    @classmethod
    def dispatch_hook(cls, _pkt=None, *args, **kargs):
        if _pkt and len(_pkt) >= 4:
            classnum = _pkt[2]
            if classnum in cls.registered_icmp_exts:
                return cls.registered_icmp_exts[classnum]
        return cls


class ICMPExtension_InterfaceInformation(ICMPExtension_Object):
    name = "ICMP Extension Object - Interface Information Object (RFC5837)"

    fields_desc = [
        ShortField("len", None),
        ByteEnumField("classnum", 2, _ICMP_classnums),
        BitField("classtype", 0, 2),
        BitField("reserved", 0, 2),
        BitField("has_ifindex", 0, 1),
        BitField("has_ipaddr", 0, 1),
        BitField("has_ifname", 0, 1),
        BitField("has_mtu", 0, 1),
        ConditionalField(IntField("ifindex", None), lambda pkt: pkt.has_ifindex == 1),
        ConditionalField(ShortField("afi", None), lambda pkt: pkt.has_ipaddr == 1),
        ConditionalField(ShortField("reserved2", 0), lambda pkt: pkt.has_ipaddr == 1),
        ConditionalField(IPField("ip4", None), lambda pkt: pkt.afi == 1),
        ConditionalField(IP6Field("ip6", None), lambda pkt: pkt.afi == 2),
        ConditionalField(
            FieldLenField("ifname_len", None, fmt="B", length_of="ifname"),
            lambda pkt: pkt.has_ifname == 1,
        ),
        ConditionalField(
            StrLenField("ifname", None, length_from=lambda pkt: pkt.ifname_len),
            lambda pkt: pkt.has_ifname == 1,
        ),
        ConditionalField(IntField("mtu", None), lambda pkt: pkt.has_mtu == 1),
    ]

    def self_build(self, **kwargs):
        if self.afi is None:
            if self.ip4 is not None:
                self.afi = 1
            elif self.ip6 is not None:
                self.afi = 2
        return ICMPExtension_Object.self_build(self, **kwargs)


class ICMPExtension_Header(Packet):
    r"""
    ICMP Extension per RFC4884.

    Example::

        pkt = IP(dst="127.0.0.1", src="127.0.0.1") / ICMP(
            type="time-exceeded",
            code="ttl-zero-during-transit",
            ext=ICMPExtension_Header() / ICMPExtension_InterfaceInformation(
                has_ifindex=1,
                has_ipaddr=1,
                has_ifname=1,
                ip4="10.10.10.10",
                ifname="hey",
            )
        ) / IPerror(src="12.4.4.4", dst="12.1.1.1") / \
            UDPerror(sport=42315, dport=33440) /  \
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
    """

    name = "ICMP Extension Header (RFC4884)"
    show_indent = 0
    fields_desc = [
        BitField("version", 2, 4),
        BitField("reserved", 0, 12),
        XShortField("chksum", None),
    ]

    _min_ieo_len = len(ICMPExtension_Object())

    def post_build(self, p, pay):
        p += pay
        if self.chksum is None:
            ck = checksum(p)
            p = p[:2] + chb(ck >> 8) + chb(ck & 0xFF) + p[4:]
        return p

    def guess_payload_class(self, payload):
        if len(payload) < self._min_ieo_len:
            return Packet.guess_payload_class(self, payload)
        return ICMPExtension_Object


class _ICMPExtensionField(TrailerField):
    # We use a TrailerField for building only. Dissection is normal.

    def __init__(self):
        super(_ICMPExtensionField, self).__init__(
            PacketField(
                "ext",
                None,
                ICMPExtension_Header,
            ),
        )

    def getfield(self, pkt, s):
        # RFC4884 section 5.2 says if the ICMP packet length
        # is >144 then ICMP extensions start at byte 137.
        if len(pkt.original) < 144:
            return s, None
        offset = 136 + len(s) - len(pkt.original)
        data = s[offset:]
        # Validate checksum
        if checksum(data) == data[3:5]:
            return s, None  # failed
        # Dissect
        return s[:offset], ICMPExtension_Header(data)

    def addfield(self, pkt, s, val):
        if val is None:
            return s
        data = bytes(val)
        # Calc how much padding we need, not how much we deserve
        pad = 136 - len(pkt.payload) - len(s)
        if pad < 0:
            warning("ICMPExtension_Header is after the 136th octet of ICMP.")
            return data
        return super(_ICMPExtensionField, self).addfield(pkt, s, b"\x00" * pad + data)


class _ICMPExtensionPadField(TrailerField):
    def __init__(self):
        super(_ICMPExtensionPadField, self).__init__(
            StrFixedLenField("extpad", "", length=0)
        )

    def i2repr(self, pkt, s):
        if s and s == b"\x00" * len(s):
            return "b'' (%s octets)" % len(s)
        return self.fld.i2repr(pkt, s)


def _ICMP_extpad_post_dissection(self, pkt):
    # If we have padding, put it in 'extpad' for re-build
    if pkt.ext:
        pad = pkt.lastlayer()
        if isinstance(pad, conf.padding_layer):
            pad.underlayer.remove_payload()
            pkt.extpad = pad.load


icmptypes = {0: "echo-reply",
             3: "dest-unreach",
             4: "source-quench",
             5: "redirect",
             8: "echo-request",
             9: "router-advertisement",
             10: "router-solicitation",
             11: "time-exceeded",
             12: "parameter-problem",
             13: "timestamp-request",
             14: "timestamp-reply",
             15: "information-request",
             16: "information-response",
             17: "address-mask-request",
             18: "address-mask-reply",
             30: "traceroute",
             31: "datagram-conversion-error",
             32: "mobile-host-redirect",
             33: "ipv6-where-are-you",
             34: "ipv6-i-am-here",
             35: "mobile-registration-request",
             36: "mobile-registration-reply",
             37: "domain-name-request",
             38: "domain-name-reply",
             39: "skip",
             40: "photuris"}


icmpcodes = {3: {0: "network-unreachable",
                    1: "host-unreachable",
                    2: "protocol-unreachable",
                    3: "port-unreachable",
                    4: "fragmentation-needed",
                    5: "source-route-failed",
                    6: "network-unknown",
                    7: "host-unknown",
                    9: "network-prohibited",
                    10: "host-prohibited",
                    11: "TOS-network-unreachable",
                    12: "TOS-host-unreachable",
                    13: "communication-prohibited",
                    14: "host-precedence-violation",
                    15: "precedence-cutoff", },
             5: {0: "network-redirect",
                 1: "host-redirect",
                 2: "TOS-network-redirect",
                 3: "TOS-host-redirect", },
             11: {0: "ttl-zero-during-transit",
                  1: "ttl-zero-during-reassembly", },
             12: {0: "ip-header-bad",
                  1: "required-option-missing", },
             40: {0: "bad-spi",
                  1: "authentication-failed",
                  2: "decompression-failed",
                  3: "decryption-failed",
                  4: "need-authentification",
                  5: "need-authorization", }, }


_icmp_answers = [
    (8, 0),
    (13, 14),
    (15, 16),
    (17, 18),
    (33, 34),
    (35, 36),
    (37, 38),
]

icmp_id_seq_types = [0, 8, 13, 14, 15, 16, 17, 18, 37, 38]


class ICMP(Packet):
    name = "ICMP"
    fields_desc = [
        ByteEnumField("type", 8, icmptypes),
        MultiEnumField("code", 0, icmpcodes,
                       depends_on=lambda pkt:pkt.type, fmt="B"),
        XShortField("chksum", None),
        ConditionalField(
            XShortField("id", 0),
            lambda pkt: pkt.type in icmp_id_seq_types
        ),
        ConditionalField(
            XShortField("seq", 0),
            lambda pkt: pkt.type in icmp_id_seq_types
        ),
        ConditionalField(
            # Timestamp only (RFC792)
            ICMPTimeStampField("ts_ori", None),
            lambda pkt: pkt.type in [13, 14]
        ),
        ConditionalField(
            # Timestamp only (RFC792)
            ICMPTimeStampField("ts_rx", None),
            lambda pkt: pkt.type in [13, 14]
        ),
        ConditionalField(
            # Timestamp only (RFC792)
            ICMPTimeStampField("ts_tx", None),
            lambda pkt: pkt.type in [13, 14]
        ),
        ConditionalField(
            # Redirect only (RFC792)
            IPField("gw", "0.0.0.0"),
            lambda pkt: pkt.type == 5
        ),
        ConditionalField(
            # Parameter problem only (RFC792)
            ByteField("ptr", 0),
            lambda pkt: pkt.type == 12
        ),
        ConditionalField(
            ByteField("reserved", 0),
            lambda pkt: pkt.type in [3, 11]
        ),
        ConditionalField(
            ByteField("length", 0),
            lambda pkt: pkt.type in [3, 11, 12]
        ),
        ConditionalField(
            IPField("addr_mask", "0.0.0.0"),
            lambda pkt: pkt.type in [17, 18]
        ),
        ConditionalField(
            ShortField("nexthopmtu", 0),
            lambda pkt: pkt.type == 3
        ),
        MultipleTypeField(
            [
                (ShortField("unused", 0),
                    lambda pkt:pkt.type in [11, 12]),
                (IntField("unused", 0),
                    lambda pkt:pkt.type not in [0, 3, 5, 8, 11, 12,
                                                13, 14, 15, 16, 17,
                                                18])
            ],
            StrFixedLenField("unused", "", length=0),
        ),
        # RFC4884 ICMP extension
        ConditionalField(
            _ICMPExtensionPadField(),
            lambda pkt: pkt.type in [3, 11, 12],
        ),
        ConditionalField(
            _ICMPExtensionField(),
            lambda pkt: pkt.type in [3, 11, 12],
        ),
    ]

    # To handle extpad
    post_dissection = _ICMP_extpad_post_dissection

    def post_build(self, p, pay):
        p += pay
        if self.chksum is None:
            ck = checksum(p)
            p = p[:2] + chb(ck >> 8) + chb(ck & 0xff) + p[4:]
        return p

    def hashret(self):
        if self.type in icmp_id_seq_types:
            return struct.pack("HH", self.id, self.seq) + self.payload.hashret()  # noqa: E501
        return self.payload.hashret()

    def answers(self, other):
        if not isinstance(other, ICMP):
            return 0
        if ((other.type, self.type) in _icmp_answers and
            self.id == other.id and
                self.seq == other.seq):
            return 1
        return 0

    def guess_payload_class(self, payload):
        if self.type in [3, 4, 5, 11, 12]:
            return IPerror
        else:
            return None

    def mysummary(self):
        extra = ""
        if self.ext:
            extra = self.ext.payload.sprintf(" ext:%classnum%")
        if isinstance(self.underlayer, IP):
            return self.underlayer.sprintf(
                "ICMP %IP.src% > %IP.dst% %ICMP.type% %ICMP.code%"
            ) + extra
        else:
            return self.sprintf("ICMP %ICMP.type% %ICMP.code%") + extra


# IP / TCP / UDP error packets

class IPerror(IP):
    name = "IP in ICMP"

    def answers(self, other):
        if not isinstance(other, IP):
            return 0

        # Check if IP addresses match
        test_IPsrc = not conf.checkIPsrc or self.src == other.src
        test_IPdst = self.dst == other.dst

        # Check if IP ids match
        test_IPid = not conf.checkIPID or self.id == other.id
        test_IPid |= conf.checkIPID and self.id == socket.htons(other.id)

        # Check if IP protocols match
        test_IPproto = self.proto == other.proto

        if not (test_IPsrc and test_IPdst and test_IPid and test_IPproto):
            return 0

        return self.payload.answers(other.payload)

    def mysummary(self):
        return Packet.mysummary(self)


class TCPerror(TCP):
    name = "TCP in ICMP"
    fields_desc = (
        TCP.fields_desc[:2] +
        # MayEnd after the 8 first octets.
        [MayEnd(TCP.fields_desc[2])] +
        TCP.fields_desc[3:]
    )

    def answers(self, other):
        if not isinstance(other, TCP):
            return 0
        if conf.checkIPsrc:
            if not ((self.sport == other.sport) and
                    (self.dport == other.dport)):
                return 0
        if conf.check_TCPerror_seqack:
            if self.seq is not None:
                if self.seq != other.seq:
                    return 0
            if self.ack is not None:
                if self.ack != other.ack:
                    return 0
        return 1

    def mysummary(self):
        return Packet.mysummary(self)


class UDPerror(UDP):
    name = "UDP in ICMP"

    def answers(self, other):
        if not isinstance(other, UDP):
            return 0
        if conf.checkIPsrc:
            if not ((self.sport == other.sport) and
                    (self.dport == other.dport)):
                return 0
        return 1

    def mysummary(self):
        return Packet.mysummary(self)


class ICMPerror(ICMP):
    name = "ICMP in ICMP"

    def answers(self, other):
        if not isinstance(other, ICMP):
            return 0
        if not ((self.type == other.type) and
                (self.code == other.code)):
            return 0
        if self.code in [0, 8, 13, 14, 17, 18]:
            if (self.id == other.id and
                    self.seq == other.seq):
                return 1
            else:
                return 0
        else:
            return 1

    def mysummary(self):
        return Packet.mysummary(self)


bind_layers(Ether, IP, type=2048)
bind_layers(CookedLinux, IP, proto=2048)
bind_layers(GRE, IP, proto=2048)
bind_layers(SNAP, IP, code=2048)
bind_bottom_up(Loopback, IP, type=0)
bind_layers(Loopback, IP, type=socket.AF_INET)
bind_layers(IPerror, IPerror, frag=0, proto=4)
bind_layers(IPerror, ICMPerror, frag=0, proto=1)
bind_layers(IPerror, TCPerror, frag=0, proto=6)
bind_layers(IPerror, UDPerror, frag=0, proto=17)
bind_layers(IP, IP, frag=0, proto=4)
bind_layers(IP, ICMP, frag=0, proto=1)
bind_layers(IP, TCP, frag=0, proto=6)
bind_layers(IP, UDP, frag=0, proto=17)
bind_layers(IP, GRE, frag=0, proto=47)
bind_layers(UDP, GRE, dport=4754)

conf.l2types.register(DLT_RAW, IP)
conf.l2types.register_num2layer(DLT_RAW_ALT, IP)
conf.l2types.register(DLT_IPV4, IP)
if OPENBSD:
    conf.l2types.register_num2layer(228, IP)

conf.l3types.register(ETH_P_IP, IP)
conf.l3types.register_num2layer(ETH_P_ALL, IP)


def inet_register_l3(l2, l3):
    """
    Resolves the default L2 destination address when IP is used.
    """
    return getmacbyip(l3.dst)


conf.neighbor.register_l3(Ether, IP, inet_register_l3)
conf.neighbor.register_l3(Dot3, IP, inet_register_l3)


###################
#  Fragmentation  #
###################

@conf.commands.register
def fragment(pkt, fragsize=1480):
    """Fragment a big IP datagram"""
    if fragsize < 8:
        warning("fragsize cannot be lower than 8")
        fragsize = max(fragsize, 8)
    lastfragsz = fragsize
    fragsize -= fragsize % 8
    lst = []
    for p in pkt:
        s = raw(p[IP].payload)
        nb = (len(s) - lastfragsz + fragsize - 1) // fragsize + 1
        for i in range(nb):
            q = p.copy()
            del q[IP].payload
            del q[IP].chksum
            del q[IP].len
            if i != nb - 1:
                q[IP].flags |= 1
                fragend = (i + 1) * fragsize
            else:
                fragend = i * fragsize + lastfragsz
            q[IP].frag += i * fragsize // 8
            r = conf.raw_layer(load=s[i * fragsize:fragend])
            r.overload_fields = p[IP].payload.overload_fields.copy()
            q.add_payload(r)
            lst.append(q)
    return lst


@conf.commands.register
def overlap_frag(p, overlap, fragsize=8, overlap_fragsize=None):
    """Build overlapping fragments to bypass NIPS

p:                the original packet
overlap:          the overlapping data
fragsize:         the fragment size of the packet
overlap_fragsize: the fragment size of the overlapping packet"""

    if overlap_fragsize is None:
        overlap_fragsize = fragsize
    q = p.copy()
    del q[IP].payload
    q[IP].add_payload(overlap)

    qfrag = fragment(q, overlap_fragsize)
    qfrag[-1][IP].flags |= 1
    return qfrag + fragment(p, fragsize)


class BadFragments(ValueError):
    def __init__(self, *args, **kwargs):
        self.frags = kwargs.pop("frags", None)
        super(BadFragments, self).__init__(*args, **kwargs)


def _defrag_iter_and_check_offsets(frags):
    """
    Internal generator used in _defrag_ip_pkt
    """
    offset = 0
    for pkt, o, length in frags:
        if offset != o:
            if offset > o:
                op = ">"
            else:
                op = "<"
            warning("Fragment overlap (%i %s %i) on %r" % (offset, op, o, pkt))
            raise BadFragments
        offset += length
        yield bytes(pkt[IP].payload)


def _defrag_ip_pkt(pkt, frags):
    """
    Defragment a single IP packet.

    :param pkt: the new pkt
    :param frags: a defaultdict(list) used for storage
    :return: a tuple (fragmented, defragmented_value)
    """
    ip = pkt[IP]
    if pkt.frag != 0 or ip.flags.MF:
        # fragmented !
        uid = (ip.id, ip.src, ip.dst, ip.proto)
        if ip.len is None or ip.ihl is None:
            fraglen = len(ip.payload)
        else:
            fraglen = ip.len - (ip.ihl << 2)
        # (pkt, frag offset, frag len)
        frags[uid].append((pkt, ip.frag << 3, fraglen))
        if not ip.flags.MF:  # no more fragments = last fragment
            curfrags = sorted(frags[uid], key=lambda x: x[1])  # sort by offset
            try:
                data = b"".join(_defrag_iter_and_check_offsets(curfrags))
            except ValueError:
                # bad fragment
                badfrags = frags[uid]
                del frags[uid]
                raise BadFragments(frags=badfrags)
            # re-build initial packet without fragmentation
            p = curfrags[0][0].copy()
            pay_class = p[IP].payload.__class__
            p[IP].flags.MF = False
            p[IP].remove_payload()
            p[IP].len = None
            p[IP].chksum = None
            # append defragmented payload
            p /= pay_class(data)
            # cleanup
            del frags[uid]
            return True, p
        return True, None
    return False, pkt


def _defrag_logic(plist, complete=False):
    """
    Internal function used to defragment a list of packets.
    It contains the logic behind the defrag() and defragment() functions
    """
    frags = defaultdict(list)
    final = []
    notfrag = []
    badfrag = []
    # Defrag
    for i, pkt in enumerate(plist):
        if IP not in pkt:
            # no IP layer
            if complete:
                final.append(pkt)
            continue
        try:
            fragmented, defragmented_value = _defrag_ip_pkt(
                pkt,
                frags,
            )
        except BadFragments as ex:
            if complete:
                final.extend(ex.frags)
            else:
                badfrag.extend(ex.frags)
            continue
        if complete and defragmented_value:
            final.append(defragmented_value)
        elif defragmented_value:
            if fragmented:
                final.append(defragmented_value)
            else:
                notfrag.append(defragmented_value)
    # Return
    if complete:
        if hasattr(plist, "listname"):
            name = "Defragmented %s" % plist.listname
        else:
            name = "Defragmented"
        return PacketList(final, name=name)
    else:
        return PacketList(notfrag), PacketList(final), PacketList(badfrag)


@conf.commands.register
def defrag(plist):
    """defrag(plist) -> ([not fragmented], [defragmented],
                  [ [bad fragments], [bad fragments], ... ])"""
    return _defrag_logic(plist, complete=False)


@conf.commands.register
def defragment(plist):
    """defragment(plist) -> plist defragmented as much as possible """
    return _defrag_logic(plist, complete=True)


# Add timeskew_graph() method to PacketList
def _packetlist_timeskew_graph(self, ip, **kargs):
    """Tries to graph the timeskew between the timestamps and real time for a given ip"""  # noqa: E501
    # Defer imports of matplotlib until its needed
    # because it has a heavy dep chain
    from scapy.libs.matplot import (
        plt,
        MATPLOTLIB_INLINED,
        MATPLOTLIB_DEFAULT_PLOT_KARGS
    )

    # Filter TCP segments which source address is 'ip'
    tmp = (self._elt2pkt(x) for x in self.res)
    b = (x for x in tmp if IP in x and x[IP].src == ip and TCP in x)

    # Build a list of tuples (creation_time, replied_timestamp)
    c = []
    tsf = ICMPTimeStampField("", None)
    for p in b:
        opts = p.getlayer(TCP).options
        for o in opts:
            if o[0] == "Timestamp":
                c.append((p.time, tsf.any2i("", o[1][0])))

    # Stop if the list is empty
    if not c:
        warning("No timestamps found in packet list")
        return []

    # Prepare the data that will be plotted
    first_creation_time = c[0][0]
    first_replied_timestamp = c[0][1]

    def _wrap_data(ts_tuple, wrap_seconds=2000):
        """Wrap the list of tuples."""

        ct, rt = ts_tuple  # (creation_time, replied_timestamp)
        X = ct % wrap_seconds
        Y = ((ct - first_creation_time) - ((rt - first_replied_timestamp) / 1000.0))  # noqa: E501

        return X, Y

    data = [_wrap_data(e) for e in c]

    # Mimic the default gnuplot output
    if kargs == {}:
        kargs = MATPLOTLIB_DEFAULT_PLOT_KARGS
    lines = plt.plot(data, **kargs)

    # Call show() if matplotlib is not inlined
    if not MATPLOTLIB_INLINED:
        plt.show()

    return lines


_PacketList.timeskew_graph = _packetlist_timeskew_graph


# Create a new packet list
class TracerouteResult(SndRcvList):
    __slots__ = ["graphdef", "graphpadding", "graphASres", "padding", "hloc",
                 "nloc"]

    def __init__(self, res=None, name="Traceroute", stats=None):
        SndRcvList.__init__(self, res, name, stats)
        self.graphdef = None
        self.graphASres = None
        self.padding = 0
        self.hloc = None
        self.nloc = None

    def show(self):
        return self.make_table(lambda s, r: (s.sprintf("%IP.dst%:{TCP:tcp%ir,TCP.dport%}{UDP:udp%ir,UDP.dport%}{ICMP:ICMP}"),  # noqa: E501
                                             s.ttl,
                                             r.sprintf("%-15s,IP.src% {TCP:%TCP.flags%}{ICMP:%ir,ICMP.type%}")))  # noqa: E501

    def get_trace(self):
        trace = {}
        for s, r in self.res:
            if IP not in s:
                continue
            d = s[IP].dst
            if d not in trace:
                trace[d] = {}
            trace[d][s[IP].ttl] = r[IP].src, ICMP not in r
        for k in trace.values():
            try:
                m = min(x for x, y in k.items() if y[1])
            except ValueError:
                continue
            for li in list(k):  # use list(): k is modified in the loop
                if li > m:
                    del k[li]
        return trace

    def trace3D(self, join=True):
        """Give a 3D representation of the traceroute.
        right button: rotate the scene
        middle button: zoom
        shift-left button: move the scene
        left button on a ball: toggle IP displaying
        double-click button on a ball: scan ports 21,22,23,25,80 and 443 and display the result"""  # noqa: E501
        # When not ran from a notebook, vpython pooly closes itself
        # using os._exit once finished. We pack it into a Process
        import multiprocessing
        p = multiprocessing.Process(target=self.trace3D_notebook)
        p.start()
        if join:
            p.join()

    def trace3D_notebook(self):
        """Same than trace3D, used when ran from Jupyter notebooks"""
        trace = self.get_trace()
        import vpython

        class IPsphere(vpython.sphere):
            def __init__(self, ip, **kargs):
                vpython.sphere.__init__(self, **kargs)
                self.ip = ip
                self.label = None
                self.setlabel(self.ip)
                self.last_clicked = None
                self.full = False
                self.savcolor = vpython.vec(*self.color.value)

            def fullinfos(self):
                self.full = True
                self.color = vpython.vec(1, 0, 0)
                a, b = sr(IP(dst=self.ip) / TCP(dport=[21, 22, 23, 25, 80, 443], flags="S"), timeout=2, verbose=0)  # noqa: E501
                if len(a) == 0:
                    txt = "%s:\nno results" % self.ip
                else:
                    txt = "%s:\n" % self.ip
                    for s, r in a:
                        txt += r.sprintf("{TCP:%IP.src%:%TCP.sport% %TCP.flags%}{TCPerror:%IPerror.dst%:%TCPerror.dport% %IP.src% %ir,ICMP.type%}\n")  # noqa: E501
                self.setlabel(txt, visible=1)

            def unfull(self):
                self.color = self.savcolor
                self.full = False
                self.setlabel(self.ip)

            def setlabel(self, txt, visible=None):
                if self.label is not None:
                    if visible is None:
                        visible = self.label.visible
                    self.label.visible = 0
                elif visible is None:
                    visible = 0
                self.label = vpython.label(text=txt, pos=self.pos, space=self.radius, xoffset=10, yoffset=20, visible=visible)  # noqa: E501

            def check_double_click(self):
                try:
                    if self.full or not self.label.visible:
                        return False
                    if self.last_clicked is not None:
                        return (time.time() - self.last_clicked) < 0.5
                    return False
                finally:
                    self.last_clicked = time.time()

            def action(self):
                self.label.visible ^= 1
                if self.full:
                    self.unfull()

        vpython.scene = vpython.canvas()
        vpython.scene.title = "<center><u><b>%s</b></u></center>" % self.listname  # noqa: E501
        vpython.scene.append_to_caption(
            re.sub(
                r'\%(.*)\%',
                r'<span style="color: red">\1</span>',
                re.sub(
                    r'\`(.*)\`',
                    r'<span style="color: #3399ff">\1</span>',
                    """<u><b>Commands:</b></u>
%Click% to toggle information about a node.
%Double click% to perform a quick web scan on this node.
<u><b>Camera usage:</b></u>
`Right button drag or Ctrl-drag` to rotate "camera" to view scene.
`Shift-drag` to move the object around.
`Middle button or Alt-drag` to drag up or down to zoom in or out.
  On a two-button mouse, `middle is wheel or left + right`.
Touch screen: pinch/extend to zoom, swipe or two-finger rotate."""
                )
            )
        )
        vpython.scene.exit = True
        rings = {}
        tr3d = {}
        for i in trace:
            tr = trace[i]
            tr3d[i] = []
            for t in range(1, max(tr) + 1):
                if t not in rings:
                    rings[t] = []
                if t in tr:
                    if tr[t] not in rings[t]:
                        rings[t].append(tr[t])
                    tr3d[i].append(rings[t].index(tr[t]))
                else:
                    rings[t].append(("unk", -1))
                    tr3d[i].append(len(rings[t]) - 1)

        for t in rings:
            r = rings[t]
            tmp_len = len(r)
            for i in range(tmp_len):
                if r[i][1] == -1:
                    col = vpython.vec(0.75, 0.75, 0.75)
                elif r[i][1]:
                    col = vpython.color.green
                else:
                    col = vpython.color.blue

                s = IPsphere(pos=vpython.vec((tmp_len - 1) * vpython.cos(2 * i * vpython.pi / tmp_len), (tmp_len - 1) * vpython.sin(2 * i * vpython.pi / tmp_len), 2 * t),  # noqa: E501
                             ip=r[i][0],
                             color=col)
                for trlst in tr3d.values():
                    if t <= len(trlst):
                        if trlst[t - 1] == i:
                            trlst[t - 1] = s
        forecol = colgen(0.625, 0.4375, 0.25, 0.125)
        for trlst in tr3d.values():
            col = vpython.vec(*next(forecol))
            start = vpython.vec(0, 0, 0)
            for ip in trlst:
                vpython.cylinder(pos=start, axis=ip.pos - start, color=col, radius=0.2)  # noqa: E501
                start = ip.pos

        vpython.rate(50)

        # Keys handling
        # TODO: there is currently no way of closing vpython correctly
        # https://github.com/BruceSherwood/vpython-jupyter/issues/36
        # def keyboard_press(ev):
        #     k = ev.key
        #     if k == "esc" or k == "q":
        #         pass  # TODO: close
        #
        # vpython.scene.bind('keydown', keyboard_press)

        # Mouse handling
        def mouse_click(ev):
            if ev.press == "left":
                o = vpython.scene.mouse.pick
                if o and isinstance(o, IPsphere):
                    if o.check_double_click():
                        if o.ip == "unk":
                            return
                        o.fullinfos()
                    else:
                        o.action()

        vpython.scene.bind('mousedown', mouse_click)

    def world_trace(self):
        """Display traceroute results on a world map."""

        # Check that the geoip2 module can be imported
        # Doc: http://geoip2.readthedocs.io/en/latest/
        from scapy.libs.matplot import plt, MATPLOTLIB, MATPLOTLIB_INLINED

        try:
            # GeoIP2 modules need to be imported as below
            import geoip2.database
            import geoip2.errors
        except ImportError:
            log_runtime.error(
                "Cannot import geoip2. Won't be able to plot the world."
            )
            return []
        # Check availability of database
        if not conf.geoip_city:
            log_runtime.error(
                "Cannot import the geolite2 CITY database.\n"
                "Download it from http://dev.maxmind.com/geoip/geoip2/geolite2/"  # noqa: E501
                " then set its path to conf.geoip_city"
            )
            return []
        # Check availability of plotting devices
        try:
            import cartopy.crs as ccrs
        except ImportError:
            log_runtime.error(
                "Cannot import cartopy.\n"
                "More infos on http://scitools.org.uk/cartopy/docs/latest/installing.html"  # noqa: E501
            )
            return []
        if not MATPLOTLIB:
            log_runtime.error(
                "Matplotlib is not installed. Won't be able to plot the world."
            )
            return []

        # Open & read the GeoListIP2 database
        try:
            db = geoip2.database.Reader(conf.geoip_city)
        except Exception:
            log_runtime.error(
                "Cannot open geoip2 database at %s",
                conf.geoip_city
            )
            return []

        # Regroup results per trace
        ips = {}
        rt = {}
        ports_done = {}
        for s, r in self.res:
            ips[r.src] = None
            if s.haslayer(TCP) or s.haslayer(UDP):
                trace_id = (s.src, s.dst, s.proto, s.dport)
            elif s.haslayer(ICMP):
                trace_id = (s.src, s.dst, s.proto, s.type)
            else:
                trace_id = (s.src, s.dst, s.proto, 0)
            trace = rt.get(trace_id, {})
            if not r.haslayer(ICMP) or r.type != 11:
                if trace_id in ports_done:
                    continue
                ports_done[trace_id] = None
            trace[s.ttl] = r.src
            rt[trace_id] = trace

        # Get the addresses locations
        trt = {}
        for trace_id in rt:
            trace = rt[trace_id]
            loctrace = []
            for i in range(max(trace)):
                ip = trace.get(i, None)
                if ip is None:
                    continue
                # Fetch database
                try:
                    sresult = db.city(ip)
                except geoip2.errors.AddressNotFoundError:
                    continue
                loctrace.append((sresult.location.longitude, sresult.location.latitude))  # noqa: E501
            if loctrace:
                trt[trace_id] = loctrace

        # Load the map renderer
        plt.figure(num='Scapy')
        ax = plt.axes(projection=ccrs.PlateCarree())
        # Draw countries
        ax.coastlines()
        ax.stock_img()
        # Set normal size
        ax.set_global()
        # Add title
        plt.title("Scapy traceroute results")

        from matplotlib.collections import LineCollection
        from matplotlib import colors as mcolors
        colors_cycle = iter(mcolors.BASE_COLORS)
        lines = []

        # Split traceroute measurement
        for key, trc in trt.items():
            # Get next color
            color = next(colors_cycle)
            # Gather mesurments data
            data_lines = [(trc[i], trc[i + 1]) for i in range(len(trc) - 1)]
            # Create line collection
            line_col = LineCollection(data_lines, linewidths=2,
                                      label=key[1],
                                      color=color)
            lines.append(line_col)
            ax.add_collection(line_col)
            # Create map points
            lines.extend([ax.plot(*x, marker='.', color=color) for x in trc])

        # Generate legend
        ax.legend()

        # Call show() if matplotlib is not inlined
        if not MATPLOTLIB_INLINED:
            plt.show()

        # Clean
        ax.remove()

        # Return the drawn lines
        return lines

    def make_graph(self, ASres=None, padding=0):
        self.graphASres = ASres
        self.graphpadding = padding
        ips = {}
        rt = {}
        ports = {}
        ports_done = {}
        for s, r in self.res:
            r = r.getlayer(IP) or (conf.ipv6_enabled and r[scapy.layers.inet6.IPv6]) or r  # noqa: E501
            s = s.getlayer(IP) or (conf.ipv6_enabled and s[scapy.layers.inet6.IPv6]) or s  # noqa: E501
            ips[r.src] = None
            if TCP in s:
                trace_id = (s.src, s.dst, 6, s.dport)
            elif UDP in s:
                trace_id = (s.src, s.dst, 17, s.dport)
            elif ICMP in s:
                trace_id = (s.src, s.dst, 1, s.type)
            else:
                trace_id = (s.src, s.dst, s.proto, 0)
            trace = rt.get(trace_id, {})
            ttl = conf.ipv6_enabled and scapy.layers.inet6.IPv6 in s and s.hlim or s.ttl  # noqa: E501
            if not (ICMP in r and r[ICMP].type == 11) and not (conf.ipv6_enabled and scapy.layers.inet6.IPv6 in r and scapy.layers.inet6.ICMPv6TimeExceeded in r):  # noqa: E501
                if trace_id in ports_done:
                    continue
                ports_done[trace_id] = None
                p = ports.get(r.src, [])
                if TCP in r:
                    p.append(r.sprintf("<T%ir,TCP.sport%> %TCP.sport% %TCP.flags%"))  # noqa: E501
                    trace[ttl] = r.sprintf('"%r,src%":T%ir,TCP.sport%')
                elif UDP in r:
                    p.append(r.sprintf("<U%ir,UDP.sport%> %UDP.sport%"))
                    trace[ttl] = r.sprintf('"%r,src%":U%ir,UDP.sport%')
                elif ICMP in r:
                    p.append(r.sprintf("<I%ir,ICMP.type%> ICMP %ICMP.type%"))
                    trace[ttl] = r.sprintf('"%r,src%":I%ir,ICMP.type%')
                else:
                    p.append(r.sprintf("{IP:<P%ir,proto%> IP %proto%}{IPv6:<P%ir,nh%> IPv6 %nh%}"))  # noqa: E501
                    trace[ttl] = r.sprintf('"%r,src%":{IP:P%ir,proto%}{IPv6:P%ir,nh%}')  # noqa: E501
                ports[r.src] = p
            else:
                trace[ttl] = r.sprintf('"%r,src%"')
            rt[trace_id] = trace

        # Fill holes with unk%i nodes
        unknown_label = incremental_label("unk%i")
        blackholes = []
        bhip = {}
        for rtk in rt:
            trace = rt[rtk]
            max_trace = max(trace)
            for n in range(min(trace), max_trace):
                if n not in trace:
                    trace[n] = next(unknown_label)
            if rtk not in ports_done:
                if rtk[2] == 1:  # ICMP
                    bh = "%s %i/icmp" % (rtk[1], rtk[3])
                elif rtk[2] == 6:  # TCP
                    bh = "%s %i/tcp" % (rtk[1], rtk[3])
                elif rtk[2] == 17:  # UDP
                    bh = '%s %i/udp' % (rtk[1], rtk[3])
                else:
                    bh = '%s %i/proto' % (rtk[1], rtk[2])
                ips[bh] = None
                bhip[rtk[1]] = bh
                bh = '"%s"' % bh
                trace[max_trace + 1] = bh
                blackholes.append(bh)

        # Find AS numbers
        ASN_query_list = set(x.rsplit(" ", 1)[0] for x in ips)
        if ASres is None:
            ASNlist = []
        else:
            ASNlist = ASres.resolve(*ASN_query_list)

        ASNs = {}
        ASDs = {}
        for ip, asn, desc, in ASNlist:
            if asn is None:
                continue
            iplist = ASNs.get(asn, [])
            if ip in bhip:
                if ip in ports:
                    iplist.append(ip)
                iplist.append(bhip[ip])
            else:
                iplist.append(ip)
            ASNs[asn] = iplist
            ASDs[asn] = desc

        backcolorlist = colgen("60", "86", "ba", "ff")
        forecolorlist = colgen("a0", "70", "40", "20")

        s = "digraph trace {\n"

        s += "\n\tnode [shape=ellipse,color=black,style=solid];\n\n"

        s += "\n#ASN clustering\n"
        for asn in ASNs:
            s += '\tsubgraph cluster_%s {\n' % asn
            col = next(backcolorlist)
            s += '\t\tcolor="#%s%s%s";' % col
            s += '\t\tnode [fillcolor="#%s%s%s",style=filled];' % col
            s += '\t\tfontsize = 10;'
            s += '\t\tlabel = "%s\\n[%s]"\n' % (asn, ASDs[asn])
            for ip in ASNs[asn]:

                s += '\t\t"%s";\n' % ip
            s += "\t}\n"

        s += "#endpoints\n"
        for p in ports:
            s += '\t"%s" [shape=record,color=black,fillcolor=green,style=filled,label="%s|%s"];\n' % (p, p, "|".join(ports[p]))  # noqa: E501

        s += "\n#Blackholes\n"
        for bh in blackholes:
            s += '\t%s [shape=octagon,color=black,fillcolor=red,style=filled];\n' % bh  # noqa: E501

        if padding:
            s += "\n#Padding\n"
            pad = {}
            for snd, rcv in self.res:
                if rcv.src not in ports and rcv.haslayer(conf.padding_layer):
                    p = rcv.getlayer(conf.padding_layer).load
                    if p != b"\x00" * len(p):
                        pad[rcv.src] = None
            for rcv in pad:
                s += '\t"%s" [shape=triangle,color=black,fillcolor=red,style=filled];\n' % rcv  # noqa: E501

        s += "\n\tnode [shape=ellipse,color=black,style=solid];\n\n"

        for rtk in rt:
            s += "#---[%s\n" % repr(rtk)
            s += '\t\tedge [color="#%s%s%s"];\n' % next(forecolorlist)
            trace = rt[rtk]
            maxtrace = max(trace)
            for n in range(min(trace), maxtrace):
                s += '\t%s ->\n' % trace[n]
            s += '\t%s;\n' % trace[maxtrace]

        s += "}\n"
        self.graphdef = s

    def graph(self, ASres=conf.AS_resolver, padding=0, **kargs):
        """x.graph(ASres=conf.AS_resolver, other args):
        ASres=None          : no AS resolver => no clustering
        ASres=AS_resolver() : default whois AS resolver (riswhois.ripe.net)
        ASres=AS_resolver_cymru(): use whois.cymru.com whois database
        ASres=AS_resolver(server="whois.ra.net")
        type: output type (svg, ps, gif, jpg, etc.), passed to dot's "-T" option  # noqa: E501
        target: filename or redirect. Defaults pipe to Imagemagick's display program  # noqa: E501
        prog: which graphviz program to use"""
        if (self.graphdef is None or
            self.graphASres != ASres or
                self.graphpadding != padding):
            self.make_graph(ASres, padding)

        return do_graph(self.graphdef, **kargs)


@conf.commands.register
def traceroute(target, dport=80, minttl=1, maxttl=30, sport=RandShort(), l4=None, filter=None, timeout=2, verbose=None, **kargs):  # noqa: E501
    """Instant TCP traceroute

       :param target:  hostnames or IP addresses
       :param dport:   TCP destination port (default is 80)
       :param minttl:  minimum TTL (default is 1)
       :param maxttl:  maximum TTL (default is 30)
       :param sport:   TCP source port (default is random)
       :param l4:      use a Scapy packet instead of TCP
       :param filter:  BPF filter applied to received packets
       :param timeout: time to wait for answers (default is 2s)
       :param verbose: detailed output
       :return: an TracerouteResult, and a list of unanswered packets"""
    if verbose is None:
        verbose = conf.verb
    if filter is None:
        # we only consider ICMP error packets and TCP packets with at
        # least the ACK flag set *and* either the SYN or the RST flag
        # set
        filter = "(icmp and (icmp[0]=3 or icmp[0]=4 or icmp[0]=5 or icmp[0]=11 or icmp[0]=12)) or (tcp and (tcp[13] & 0x16 > 0x10))"  # noqa: E501
    if l4 is None:
        a, b = sr(IP(dst=target, id=RandShort(), ttl=(minttl, maxttl)) / TCP(seq=RandInt(), sport=sport, dport=dport),  # noqa: E501
                  timeout=timeout, filter=filter, verbose=verbose, **kargs)
    else:
        # this should always work
        filter = "ip"
        a, b = sr(IP(dst=target, id=RandShort(), ttl=(minttl, maxttl)) / l4,
                  timeout=timeout, filter=filter, verbose=verbose, **kargs)

    a = TracerouteResult(a.res)
    if verbose:
        a.show()
    return a, b


@conf.commands.register
def traceroute_map(ips, **kargs):
    """Util function to call traceroute on multiple targets, then
    show the different paths on a map.

    :param ips: a list of IPs on which traceroute will be called
    :param kargs: (optional) kwargs, passed to traceroute
    """
    kargs.setdefault("verbose", 0)
    return traceroute(ips)[0].world_trace()

#############################
#  Simple TCP client stack  #
#############################


class TCP_client(Automaton):
    """
    Creates a TCP Client Automaton.
    This automaton will handle TCP 3-way handshake.

    Usage: the easiest usage is to use it as a SuperSocket.
        >>> a = TCP_client.tcplink(HTTP, "www.google.com", 80)
        >>> a.send(HTTPRequest())
        >>> a.recv()

    :param ip: the ip to connect to
    :param port:
    :param src: (optional) use another source IP
    :param sport: (optional) the TCP source port (default: random)
    :param seq: (optional) initial TCP sequence number (default: random)
    """

    def parse_args(self, ip, port, srcip=None, sport=None, seq=None, ack=0, **kargs):
        from scapy.sessions import TCPSession
        self.dst = str(Net(ip))
        self.dport = port
        self.sport = sport if sport is not None else random.randrange(0, 2**16)
        self.l4 = IP(dst=ip, src=srcip) / TCP(
            sport=self.sport, dport=self.dport,
            flags=0,
            seq=seq if seq is not None else random.randrange(0, 2**32),
            ack=ack,
        )
        self.src = self.l4.src
        self.sack = self.l4[TCP].ack
        self.rel_seq = None
        self.rcvbuf = TCPSession()
        bpf = "host %s  and host %s and port %i and port %i" % (self.src,
                                                                self.dst,
                                                                self.sport,
                                                                self.dport)
        Automaton.parse_args(self, filter=bpf, **kargs)

    def _transmit_packet(self, pkt):
        """Transmits a packet from TCPSession to the SuperSocket"""
        self.oi.tcp.send(raw(pkt[TCP].payload))

    def master_filter(self, pkt):
        return (IP in pkt and
                pkt[IP].src == self.dst and
                pkt[IP].dst == self.src and
                TCP in pkt and
                pkt[TCP].sport == self.dport and
                pkt[TCP].dport == self.sport and
                self.l4[TCP].seq >= pkt[TCP].ack and  # XXX: seq/ack 2^32 wrap up  # noqa: E501
                ((self.l4[TCP].ack == 0) or (self.sack <= pkt[TCP].seq <= self.l4[TCP].ack + pkt[TCP].window)))  # noqa: E501

    @ATMT.state(initial=1)
    def START(self):
        pass

    @ATMT.state()
    def SYN_SENT(self):
        pass

    @ATMT.state()
    def ESTABLISHED(self):
        pass

    @ATMT.state()
    def LAST_ACK(self):
        pass

    @ATMT.state(final=1)
    def CLOSED(self):
        pass

    @ATMT.state(stop=1)
    def STOP(self):
        pass

    @ATMT.state()
    def STOP_SENT_FIN_ACK(self):
        pass

    @ATMT.condition(START)
    def connect(self):
        raise self.SYN_SENT()

    @ATMT.action(connect)
    def send_syn(self):
        self.l4[TCP].flags = "S"
        self.send(self.l4)
        self.l4[TCP].seq += 1

    @ATMT.receive_condition(SYN_SENT)
    def synack_received(self, pkt):
        if pkt[TCP].flags.SA:
            raise self.ESTABLISHED().action_parameters(pkt)

    @ATMT.action(synack_received)
    def send_ack_of_synack(self, pkt):
        self.l4[TCP].ack = pkt[TCP].seq + 1
        self.l4[TCP].flags = "A"
        self.send(self.l4)

    @ATMT.receive_condition(ESTABLISHED)
    def incoming_data_received(self, pkt):
        if not isinstance(pkt[TCP].payload, (NoPayload, conf.padding_layer)):
            raise self.ESTABLISHED().action_parameters(pkt)

    @ATMT.action(incoming_data_received)
    def receive_data(self, pkt):
        data = raw(pkt[TCP].payload)
        if data and self.l4[TCP].ack == pkt[TCP].seq:
            self.sack = self.l4[TCP].ack
            self.l4[TCP].ack += len(data)
            self.l4[TCP].flags = "A"
            # Answer with an Ack
            self.send(self.l4)
            # Process data - will be sent to the SuperSocket through this
            pkt = self.rcvbuf.process(pkt)
            if pkt:
                self._transmit_packet(pkt)

    @ATMT.ioevent(ESTABLISHED, name="tcp", as_supersocket="tcplink")
    def outgoing_data_received(self, fd):
        raise self.ESTABLISHED().action_parameters(fd.recv())

    @ATMT.action(outgoing_data_received)
    def send_data(self, d):
        self.l4[TCP].flags = "PA"
        self.send(self.l4 / d)
        self.l4[TCP].seq += len(d)

    @ATMT.receive_condition(ESTABLISHED)
    def reset_received(self, pkt):
        if pkt[TCP].flags.R:
            raise self.CLOSED()

    @ATMT.receive_condition(ESTABLISHED)
    def fin_received(self, pkt):
        if pkt[TCP].flags.F:
            raise self.LAST_ACK().action_parameters(pkt)

    @ATMT.action(fin_received)
    def send_finack(self, pkt):
        self.l4[TCP].flags = "FA"
        self.l4[TCP].ack = pkt[TCP].seq + 1
        self.send(self.l4)
        self.l4[TCP].seq += 1

    @ATMT.receive_condition(LAST_ACK)
    def ack_of_fin_received(self, pkt):
        if pkt[TCP].flags.A:
            raise self.CLOSED()

    @ATMT.condition(STOP)
    def stop_requested(self):
        raise self.STOP_SENT_FIN_ACK()

    @ATMT.action(stop_requested)
    def stop_send_finack(self):
        self.l4[TCP].flags = "FA"
        self.send(self.l4)
        self.l4[TCP].seq += 1

    @ATMT.receive_condition(STOP_SENT_FIN_ACK)
    def stop_fin_received(self, pkt):
        if pkt[TCP].flags.F:
            raise self.CLOSED().action_parameters(pkt)

    @ATMT.action(stop_fin_received)
    def stop_send_ack(self, pkt):
        self.l4[TCP].flags = "A"
        self.l4[TCP].ack = pkt[TCP].seq + 1
        self.send(self.l4)

    @ATMT.timeout(SYN_SENT, 1)
    def syn_ack_timeout(self):
        raise self.CLOSED()

    @ATMT.timeout(STOP_SENT_FIN_ACK, 1)
    def stop_ack_timeout(self):
        raise self.CLOSED()


#####################
#  Reporting stuff  #
#####################


@conf.commands.register
def report_ports(target, ports):
    """portscan a target and output a LaTeX table
report_ports(target, ports) -> string"""
    ans, unans = sr(IP(dst=target) / TCP(dport=ports), timeout=5)
    rep = "\\begin{tabular}{|r|l|l|}\n\\hline\n"
    for s, r in ans:
        if not r.haslayer(ICMP):
            if r.payload.flags == 0x12:
                rep += r.sprintf("%TCP.sport% & open & SA \\\\\n")
    rep += "\\hline\n"
    for s, r in ans:
        if r.haslayer(ICMP):
            rep += r.sprintf("%TCPerror.dport% & closed & ICMP type %ICMP.type%/%ICMP.code% from %IP.src% \\\\\n")  # noqa: E501
        elif r.payload.flags != 0x12:
            rep += r.sprintf("%TCP.sport% & closed & TCP %TCP.flags% \\\\\n")
    rep += "\\hline\n"
    for i in unans:
        rep += i.sprintf("%TCP.dport% & ? & unanswered \\\\\n")
    rep += "\\hline\n\\end{tabular}\n"
    return rep


@conf.commands.register
def IPID_count(lst, funcID=lambda x: x[1].id, funcpres=lambda x: x[1].summary()):  # noqa: E501
    """Identify IP id values classes in a list of packets

lst:      a list of packets
funcID:   a function that returns IP id values
funcpres: a function used to summarize packets"""
    idlst = [funcID(e) for e in lst]
    idlst.sort()
    classes = [idlst[0]]
    classes += [t[1] for t in zip(idlst[:-1], idlst[1:]) if abs(t[0] - t[1]) > 50]  # noqa: E501
    lst = [(funcID(x), funcpres(x)) for x in lst]
    lst.sort()
    print("Probably %i classes: %s" % (len(classes), classes))
    for id, pr in lst:
        print("%5i" % id, pr)


@conf.commands.register
def fragleak(target, sport=123, dport=123, timeout=0.2, onlyasc=0, count=None):
    load = "XXXXYYYYYYYYYY"
    pkt = IP(dst=target, id=RandShort(), options=b"\x00" * 40, flags=1)
    pkt /= UDP(sport=sport, dport=sport) / load
    s = conf.L3socket()
    intr = 0
    found = {}
    try:
        while count is None or count:
            if count is not None and isinstance(count, int):
                count -= 1
            try:
                if not intr:
                    s.send(pkt)
                sin = select.select([s], [], [], timeout)[0]
                if not sin:
                    continue
                ans = s.recv(1600)
                if not isinstance(ans, IP):  # TODO: IPv6
                    continue
                if not isinstance(ans.payload, ICMP):
                    continue
                if not isinstance(ans.payload.payload, IPerror):
                    continue
                if ans.payload.payload.dst != target:
                    continue
                if ans.src != target:
                    print("leak from", ans.src)
                if not ans.haslayer(conf.padding_layer):
                    continue
                leak = ans.getlayer(conf.padding_layer).load
                if leak not in found:
                    found[leak] = None
                    linehexdump(leak, onlyasc=onlyasc)
            except KeyboardInterrupt:
                if intr:
                    raise
                intr = 1
    except KeyboardInterrupt:
        pass


@conf.commands.register
def fragleak2(target, timeout=0.4, onlyasc=0, count=None):
    found = {}
    try:
        while count is None or count:
            if count is not None and isinstance(count, int):
                count -= 1

            pkt = IP(dst=target, options=b"\x00" * 40, proto=200)
            pkt /= "XXXXYYYYYYYYYYYY"
            p = sr1(pkt, timeout=timeout, verbose=0)
            if not p:
                continue
            if conf.padding_layer in p:
                leak = p[conf.padding_layer].load
                if leak not in found:
                    found[leak] = None
                    linehexdump(leak, onlyasc=onlyasc)
    except Exception:
        pass


@conf.commands.register
class connect_from_ip:
    """
    Open a TCP socket to a host:port while spoofing another IP.

    :param host: the host to connect to
    :param port: the port to connect to
    :param srcip: the IP to spoof. the cache of the gateway will
                  be poisonned with this IP.
    :param poison: (optional, default True) ARP poison the gateway (or next hop),
                   so that it answers us (only one packet).
    :param timeout: (optional) the socket timeout.

    Example - Connect to 192.168.0.1:80 spoofing 192.168.0.2::

        from scapy.layers.http import HTTP, HTTPRequest
        client = connect_from_ip("192.168.0.1", 80, "192.168.0.2")
        sock = SSLStreamSocket(client.sock, HTTP)
        resp = sock.sr1(HTTP() / HTTPRequest(Path="/"))

    Example - Connect to 192.168.0.1:443 with TLS wrapping spoofing 192.168.0.2::

        import ssl
        from scapy.layers.http import HTTP, HTTPRequest
        context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
        context.check_hostname = False
        context.verify_mode = ssl.CERT_NONE
        client = connect_from_ip("192.168.0.1", 443, "192.168.0.2")
        sock = context.wrap_socket(client.sock)
        sock = SSLStreamSocket(client.sock, HTTP)
        resp = sock.sr1(HTTP() / HTTPRequest(Path="/"))
    """

    def __init__(self, host, port, srcip, poison=True, timeout=1, debug=0):
        host = str(Net(host))
        if poison:
            # poison the next hop
            gateway = conf.route.route(host)[2]
            if gateway == "0.0.0.0":
                # on lan
                gateway = host
            getmacbyip(gateway)  # cache real gateway before poisoning
            arpcachepoison(gateway, srcip, count=1, interval=0, verbose=0)
        # create a socket pair
        self._sock, self.sock = socket.socketpair()
        self.sock.settimeout(timeout)
        self.client = TCP_client(
            host, port,
            srcip=srcip,
            external_fd={"tcp": self._sock},
            debug=debug,
        )
        # start the TCP_client
        self.client.runbg()

    def close(self):
        self.client.stop()
        self.client.destroy()
        self.sock.close()
        self._sock.close()


class ICMPEcho_am(AnsweringMachine):
    """Responds to ICMP Echo-Requests (ping)"""
    function_name = "icmpechod"

    def is_request(self, req):
        if req.haslayer(ICMP):
            icmp_req = req.getlayer(ICMP)
            if icmp_req.type == 8:  # echo-request
                return True

        return False

    def print_reply(self, req, reply):
        print("Replying %s to %s" % (reply[IP].dst, req[IP].dst))

    def make_reply(self, req):
        reply = req.copy()
        reply[ICMP].type = 0  # echo-reply
        # Force re-generation of the checksum
        reply[ICMP].chksum = None
        if req.haslayer(IP):
            reply[IP].src, reply[IP].dst = req[IP].dst, req[IP].src
            reply[IP].chksum = None
        if req.haslayer(Ether):
            reply[Ether].src, reply[Ether].dst = (
                None if req[Ether].dst == "ff:ff:ff:ff:ff:ff" else req[Ether].dst,
                req[Ether].src,
            )
        return reply


conf.stats_classic_protocols += [TCP, UDP, ICMP]
conf.stats_dot11_protocols += [TCP, UDP, ICMP]

if conf.ipv6_enabled:
    import scapy.layers.inet6