test/util.py

""" test framework utilities """

import ipaddress
import logging
import socket
from socket import AF_INET6
import os.path
from copy import deepcopy
from collections import UserDict

import scapy.compat
from scapy.layers.l2 import Ether
from scapy.layers.inet import IP
from scapy.layers.inet6 import (
    IPv6,
    IPv6ExtHdrFragment,
    IPv6ExtHdrRouting,
    IPv6ExtHdrHopByHop,
)
from scapy.packet import Raw
from scapy.utils import hexdump
from scapy.utils6 import in6_mactoifaceid

from io import BytesIO
from vpp_papi import mac_pton

# Set up an empty logger for the testcase that can be overridden as necessary
null_logger = logging.getLogger("VppTestCase.util")
null_logger.addHandler(logging.NullHandler())


def pr(packet):
    return packet.__repr__()


def ppp(headline, packet):
    """Return string containing headline and output of scapy packet.show()"""
    return "%s\n%s\n\n%s\n" % (
        headline,
        hexdump(packet, dump=True),
        packet.show(dump=True),
    )


def ppc(headline, capture, limit=10):
    """Return string containing ppp() printout for a capture.

    :param headline: printed as first line of output
    :param capture: packets to print
    :param limit: limit the print to # of packets
    """
    if not capture:
        return headline
    tail = ""
    if limit < len(capture):
        tail = "\nPrint limit reached, %s out of %s packets printed" % (
            limit,
            len(capture),
        )
    body = "".join(
        [ppp("Packet #%s:" % count, p) for count, p in zip(range(0, limit), capture)]
    )
    return "%s\n%s%s" % (headline, body, tail)


def ip4_range(ip4, s, e):
    tmp = ip4.rsplit(".", 1)[0]
    return ("%s.%d" % (tmp, i) for i in range(s, e))


def mcast_ip_to_mac(ip):
    ip = ipaddress.ip_address(ip)
    if not ip.is_multicast:
        raise ValueError("Must be multicast address.")
    ip_as_int = int(ip)
    if ip.version == 4:
        mcast_mac = "01:00:5e:%02x:%02x:%02x" % (
            (ip_as_int >> 16) & 0x7F,
            (ip_as_int >> 8) & 0xFF,
            ip_as_int & 0xFF,
        )
    else:
        mcast_mac = "33:33:%02x:%02x:%02x:%02x" % (
            (ip_as_int >> 24) & 0xFF,
            (ip_as_int >> 16) & 0xFF,
            (ip_as_int >> 8) & 0xFF,
            ip_as_int & 0xFF,
        )
    return mcast_mac


# wrapper around scapy library function.
def mk_ll_addr(mac):
    euid = in6_mactoifaceid(str(mac))
    addr = "fe80::" + euid
    return addr


def ip6_normalize(ip6):
    return socket.inet_ntop(socket.AF_INET6, socket.inet_pton(socket.AF_INET6, ip6))


def get_core_path(tempdir):
    return "%s/%s" % (tempdir, get_core_pattern())


def is_core_present(tempdir):
    return os.path.isfile(get_core_path(tempdir))


def get_core_pattern():
    with open("/proc/sys/kernel/core_pattern", "r") as f:
        corefmt = f.read().strip()
    return corefmt


def check_core_path(logger, core_path):
    corefmt = get_core_pattern()
    if corefmt.startswith("|"):
        logger.error(
            "WARNING: redirecting the core dump through a"
            " filter may result in truncated dumps."
        )
        logger.error(
            "   You may want to check the filter settings"
            " or uninstall it and edit the"
            " /proc/sys/kernel/core_pattern accordingly."
        )
        logger.error("   current core pattern is: %s" % corefmt)


class NumericConstant:

    desc_dict = {}

    def __init__(self, value):
        self._value = value

    def __int__(self):
        return self._value

    def __long__(self):
        return self._value

    def __str__(self):
        if self._value in self.desc_dict:
            return self.desc_dict[self._value]
        return ""


class Host:
    """Generic test host "connected" to VPPs interface."""

    @property
    def mac(self):
        """MAC address"""
        return self._mac

    @property
    def bin_mac(self):
        """MAC address"""
        return mac_pton(self._mac)

    @property
    def ip4(self):
        """IPv4 address - string"""
        return self._ip4

    @property
    def ip4n(self):
        """IPv4 address of remote host - raw, suitable as API parameter."""
        return socket.inet_pton(socket.AF_INET, self._ip4)

    @property
    def ip6(self):
        """IPv6 address - string"""
        return self._ip6

    @property
    def ip6n(self):
        """IPv6 address of remote host - raw, suitable as API parameter."""
        return socket.inet_pton(socket.AF_INET6, self._ip6)

    @property
    def ip6_ll(self):
        """IPv6 link-local address - string"""
        return self._ip6_ll

    @property
    def ip6n_ll(self):
        """IPv6 link-local address of remote host -
        raw, suitable as API parameter."""
        return socket.inet_pton(socket.AF_INET6, self._ip6_ll)

    def __eq__(self, other):
        if isinstance(other, Host):
            return (
                self.mac == other.mac
                and self.ip4 == other.ip4
                and self.ip6 == other.ip6
                and self.ip6_ll == other.ip6_ll
            )
        else:
            return False

    def __ne__(self, other):
        return not self.__eq__(other)

    def __repr__(self):
        return "Host { mac:%s ip4:%s ip6:%s ip6_ll:%s }" % (
            self.mac,
            self.ip4,
            self.ip6,
            self.ip6_ll,
        )

    def __hash__(self):
        return hash(self.__repr__())

    def __init__(self, mac=None, ip4=None, ip6=None, ip6_ll=None):
        self._mac = mac
        self._ip4 = ip4
        self._ip6 = ip6
        self._ip6_ll = ip6_ll


class L4_Conn:
    """L4 'connection' tied to two VPP interfaces"""

    def __init__(self, testcase, if1, if2, af, l4proto, port1, port2):
        self.testcase = testcase
        self.ifs = [None, None]
        self.ifs[0] = if1
        self.ifs[1] = if2
        self.address_family = af
        self.l4proto = l4proto
        self.ports = [None, None]
        self.ports[0] = port1
        self.ports[1] = port2
        self

    def pkt(self, side, l4args={}, payload="x"):
        is_ip6 = 1 if self.address_family == AF_INET6 else 0
        s0 = side
        s1 = 1 - side
        src_if = self.ifs[s0]
        dst_if = self.ifs[s1]
        layer_3 = [
            IP(src=src_if.remote_ip4, dst=dst_if.remote_ip4),
            IPv6(src=src_if.remote_ip6, dst=dst_if.remote_ip6),
        ]
        merged_l4args = {"sport": self.ports[s0], "dport": self.ports[s1]}
        merged_l4args.update(l4args)
        p = (
            Ether(dst=src_if.local_mac, src=src_if.remote_mac)
            / layer_3[is_ip6]
            / self.l4proto(**merged_l4args)
            / Raw(payload)
        )
        return p

    def send(self, side, flags=None, payload=""):
        l4args = {}
        if flags is not None:
            l4args["flags"] = flags
        self.ifs[side].add_stream(self.pkt(side, l4args=l4args, payload=payload))
        self.ifs[1 - side].enable_capture()
        self.testcase.pg_start()

    def recv(self, side):
        p = self.ifs[side].wait_for_packet(1)
        return p

    def send_through(self, side, flags=None, payload=""):
        self.send(side, flags, payload)
        p = self.recv(1 - side)
        return p

    def send_pingpong(self, side, flags1=None, flags2=None):
        p1 = self.send_through(side, flags1)
        p2 = self.send_through(1 - side, flags2)
        return [p1, p2]


class L4_CONN_SIDE:
    L4_CONN_SIDE_ZERO = 0
    L4_CONN_SIDE_ONE = 1


def fragment_rfc791(packet, fragsize, logger=null_logger):
    """
    Fragment an IPv4 packet per RFC 791
    :param packet: packet to fragment
    :param fragsize: size at which to fragment
    :note: IP options are not supported
    :returns: list of fragments
    """
    logger.debug(ppp("Fragmenting packet:", packet))
    packet = packet.__class__(scapy.compat.raw(packet))  # recalc. all values
    if len(packet[IP].options) > 0:
        raise Exception("Not implemented")
    if len(packet) <= fragsize:
        return [packet]

    pre_ip_len = len(packet) - len(packet[IP])
    ip_header_len = packet[IP].ihl * 4
    hex_packet = scapy.compat.raw(packet)
    hex_headers = hex_packet[: (pre_ip_len + ip_header_len)]
    hex_payload = hex_packet[(pre_ip_len + ip_header_len) :]

    pkts = []
    ihl = packet[IP].ihl
    otl = len(packet[IP])
    nfb = int((fragsize - pre_ip_len - ihl * 4) / 8)
    fo = packet[IP].frag

    p = packet.__class__(hex_headers + hex_payload[: nfb * 8])
    p[IP].flags = "MF"
    p[IP].frag = fo
    p[IP].len = ihl * 4 + nfb * 8
    del p[IP].chksum
    pkts.append(p)

    p = packet.__class__(hex_headers + hex_payload[nfb * 8 :])
    p[IP].len = otl - nfb * 8
    p[IP].frag = fo + nfb
    del p[IP].chksum

    more_fragments = fragment_rfc791(p, fragsize, logger)
    pkts.extend(more_fragments)

    return pkts


def fragment_rfc8200(packet, identification, fragsize, logger=null_logger):
    """
    Fragment an IPv6 packet per RFC 8200
    :param packet: packet to fragment
    :param fragsize: size at which to fragment
    :note: IP options are not supported
    :returns: list of fragments
    """
    packet = packet.__class__(scapy.compat.raw(packet))  # recalc. all values
    if len(packet) <= fragsize:
        return [packet]
    logger.debug(ppp("Fragmenting packet:", packet))
    pkts = []
    counter = 0
    routing_hdr = None
    hop_by_hop_hdr = None
    upper_layer = None
    seen_ipv6 = False
    ipv6_nr = -1
    l = packet.getlayer(counter)
    while l is not None:
        if l.__class__ is IPv6:
            if seen_ipv6:
                # ignore 2nd IPv6 header and everything below..
                break
            ipv6_nr = counter
            seen_ipv6 = True
        elif l.__class__ is IPv6ExtHdrFragment:
            raise Exception("Already fragmented")
        elif l.__class__ is IPv6ExtHdrRouting:
            routing_hdr = counter
        elif l.__class__ is IPv6ExtHdrHopByHop:
            hop_by_hop_hdr = counter
        elif (
            seen_ipv6
            and not upper_layer
            and not l.__class__.__name__.startswith("IPv6ExtHdr")
        ):
            upper_layer = counter
        counter = counter + 1
        l = packet.getlayer(counter)

    logger.debug(
        "Layers seen: IPv6(#%s), Routing(#%s), HopByHop(#%s), upper(#%s)"
        % (ipv6_nr, routing_hdr, hop_by_hop_hdr, upper_layer)
    )

    if upper_layer is None:
        raise Exception("Upper layer header not found in IPv6 packet")

    last_per_fragment_hdr = ipv6_nr
    if routing_hdr is None:
        if hop_by_hop_hdr is not None:
            last_per_fragment_hdr = hop_by_hop_hdr
    else:
        last_per_fragment_hdr = routing_hdr
    logger.debug("Last per-fragment hdr is #%s" % (last_per_fragment_hdr))

    per_fragment_headers = packet.copy()
    per_fragment_headers[last_per_fragment_hdr].remove_payload()
    logger.debug(ppp("Per-fragment headers:", per_fragment_headers))

    ext_and_upper_layer = packet.getlayer(last_per_fragment_hdr)[1]
    hex_payload = scapy.compat.raw(ext_and_upper_layer)
    logger.debug("Payload length is %s" % len(hex_payload))
    logger.debug(ppp("Ext and upper layer:", ext_and_upper_layer))

    fragment_ext_hdr = IPv6ExtHdrFragment()
    logger.debug(ppp("Fragment header:", fragment_ext_hdr))

    len_ext_and_upper_layer_payload = len(ext_and_upper_layer.payload)
    if not len_ext_and_upper_layer_payload and hasattr(ext_and_upper_layer, "data"):
        len_ext_and_upper_layer_payload = len(ext_and_upper_layer.data)

    if (
        len(per_fragment_headers)
        + len(fragment_ext_hdr)
        + len(ext_and_upper_layer)
        - len_ext_and_upper_layer_payload
        > fragsize
    ):
        raise Exception(
            "Cannot fragment this packet - MTU too small "
            "(%s, %s, %s, %s, %s)"
            % (
                len(per_fragment_headers),
                len(fragment_ext_hdr),
                len(ext_and_upper_layer),
                len_ext_and_upper_layer_payload,
                fragsize,
            )
        )

    orig_nh = packet[IPv6].nh
    p = per_fragment_headers
    del p[IPv6].plen
    del p[IPv6].nh
    p = p / fragment_ext_hdr
    del p[IPv6ExtHdrFragment].nh
    first_payload_len_nfb = int((fragsize - len(p)) / 8)
    p = p / Raw(hex_payload[: first_payload_len_nfb * 8])
    del p[IPv6].plen
    p[IPv6ExtHdrFragment].nh = orig_nh
    p[IPv6ExtHdrFragment].id = identification
    p[IPv6ExtHdrFragment].offset = 0
    p[IPv6ExtHdrFragment].m = 1
    p = p.__class__(scapy.compat.raw(p))
    logger.debug(ppp("Fragment %s:" % len(pkts), p))
    pkts.append(p)
    offset = first_payload_len_nfb * 8
    logger.debug("Offset after first fragment: %s" % offset)
    while len(hex_payload) > offset:
        p = per_fragment_headers
        del p[IPv6].plen
        del p[IPv6].nh
        p = p / fragment_ext_hdr
        del p[IPv6ExtHdrFragment].nh
        l_nfb = int((fragsize - len(p)) / 8)
        p = p / Raw(hex_payload[offset : offset + l_nfb * 8])
        p[IPv6ExtHdrFragment].nh = orig_nh
        p[IPv6ExtHdrFragment].id = identification
        p[IPv6ExtHdrFragment].offset = int(offset / 8)
        p[IPv6ExtHdrFragment].m = 1
        p = p.__class__(scapy.compat.raw(p))
        logger.debug(ppp("Fragment %s:" % len(pkts), p))
        pkts.append(p)
        offset = offset + l_nfb * 8

    pkts[-1][IPv6ExtHdrFragment].m = 0  # reset more-flags in last fragment

    return pkts


def reassemble4_core(listoffragments, return_ip):
    buffer = BytesIO()
    first = listoffragments[0]
    buffer.seek(20)
    for pkt in listoffragments:
        buffer.seek(pkt[IP].frag * 8)
        buffer.write(bytes(pkt[IP].payload))
    first.len = len(buffer.getvalue()) + 20
    first.flags = 0
    del first.chksum
    if return_ip:
        header = bytes(first[IP])[:20]
        return first[IP].__class__(header + buffer.getvalue())
    else:
        header = bytes(first[Ether])[:34]
        return first[Ether].__class__(header + buffer.getvalue())


def reassemble4_ether(listoffragments):
    return reassemble4_core(listoffragments, False)


def reassemble4(listoffragments):
    return reassemble4_core(listoffragments, True)


class UnexpectedPacketError(Exception):
    def __init__(self, packet, msg=""):
        self.packet = packet
        self.msg = msg

    def __str__(self):
        return f"\nUnexpected packet:\n{pr(self.packet)}{self.msg}"


def recursive_dict_merge(dict_base, dict_update):
    """Recursively merge base dict with update dict, return merged dict"""
    for key in dict_update:
        if key in dict_base:
            if type(dict_update[key]) is dict:
                dict_base[key] = recursive_dict_merge(dict_base[key], dict_update[key])
            else:
                dict_base[key] = dict_update[key]
        else:
            dict_base[key] = dict_update[key]
    return dict_base


class StatsDiff(UserDict):
    """
    Diff dictionary is a dictionary of dictionaries of interesting stats:

        diff_dictionary =
        {
            "err" : { '/error/counter1' : 4, },
            sw_if_index1 : { '/stat/segment/counter1' : 5,
                             '/stat/segment/counter2' : 6,
                           },
            sw_if_index2 : { '/stat/segment/counter1' : 7,
                           },
        }

    It describes a per sw-if-index diffset, where each key is stat segment
    path and value is the expected change for that counter for sw-if-index.
    Special case string "err" is used for error counters, which are not per
    sw-if-index.
    """

    __slots__ = ()  # prevent setting properties to act like a dictionary

    def __init__(self, data):
        super().__init__(data)

    def __or__(self, other):
        return recursive_dict_merge(deepcopy(self.data), other)