src/vppinfra/smp.h


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/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
  Copyright (c) 2001-2005 Eliot Dresselhaus

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#ifndef included_clib_smp_h
#define included_clib_smp_h

#include <vppinfra/cache.h>
#include <vppinfra/os.h>	/* for os_panic */

#define clib_smp_swap(addr,new) __sync_lock_test_and_set(addr,new)

#if defined (i386) || defined (__x86_64__)
#define clib_smp_pause() do { asm volatile ("pause"); } while (0)
#elif defined (__aarch64__) || defined (__arm__)
#define clib_smp_pause() do { asm volatile ("isb" ::: "memory"); } while (0)
#endif

#ifndef clib_smp_pause
#define clib_smp_pause() do { } while (0)
#endif

#ifdef CLIB_UNIX
#include <sched.h>

always_inline void
os_sched_yield (void)
{
  sched_yield ();
}
#else
always_inline void
os_sched_yield (void)
{
  clib_smp_pause ();
}
#endif


#endif /* included_clib_smp_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */
import os
import time
import socket
import struct
from traceback import format_exc, format_stack

import scapy.compat
from scapy.utils import wrpcap, rdpcap, PcapReader
from scapy.plist import PacketList
from vpp_interface import VppInterface

from scapy.layers.l2 import Ether, ARP
from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
    ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
    IPv6ExtHdrHopByHop
from util import ppp, ppc
from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
from scapy.utils import inet_pton, inet_ntop


class CaptureTimeoutError(Exception):
    """ Exception raised if capture or packet doesn't appear within timeout """
    pass


def is_ipv6_misc(p):
    """ Is packet one of uninteresting IPv6 broadcasts? """
    if p.haslayer(ICMPv6ND_RA):
        if in6_ismaddr(p[IPv6].dst):
            return True
    if p.haslayer(IPv6ExtHdrHopByHop):
        for o in p[IPv6ExtHdrHopByHop].options:
            if isinstance(o, RouterAlert):
                return True
    return False


class VppPGInterface(VppInterface):
    """
    VPP packet-generator interface
    """

    @property
    def pg_index(self):
        """packet-generator interface index assigned by VPP"""
        return self._pg_index

    @property
    def gso_enabled(self):
        """gso enabled on packet-generator interface"""
        if self._gso_enabled == 0:
            return "gso-disabled"
        return "gso-enabled"

    @property
    def gso_size(self):
        """gso size on packet-generator interface"""
        return self._gso_size

    @property
    def out_path(self):
        """pcap file path - captured packets"""
        return self._out_path

    @property
    def in_path(self):
        """ pcap file path - injected packets"""
        return self._in_path

    @property
    def capture_cli(self):
        """CLI string to start capture on this interface"""
        return self._capture_cli

    @property
    def cap_name(self):
        """capture name for this interface"""
        return self._cap_name

    @property
    def input_cli(self):
        """CLI string to load the injected packets"""
        if self._nb_replays is not None:
            return "%s limit %d" % (self._input_cli, self._nb_replays)
        if self._worker is not None:
            return "%s worker %d" % (self._input_cli, self._worker)
        return self._input_cli

    @property
    def in_history_counter(self):
        """Self-incrementing counter used when renaming old pcap files"""
        v = self._in_history_counter
        self._in_history_counter += 1
        return v

    @property
    def out_history_counter(self):
        """Self-incrementing counter used when renaming old pcap files"""
        v = self._out_history_counter
        self._out_history_counter += 1
        return v

    def __init__(self, test, pg_index, gso, gso_size):
        """ Create VPP packet-generator interface """
        super(VppPGInterface, self).__init__(test)

        r = test.vapi.pg_create_interface(pg_index, gso, gso_size)
        self.set_sw_if_index(r.sw_if_index)

        self._in_history_counter = 0
        self._out_history_counter = 0
        self._out_assert_counter = 0
        self._pg_index = pg_index
        self._gso_enabled = gso
        self._gso_size = gso_size
        self._out_file = "pg%u_out.pcap" % self.pg_index
        self._out_path = self.test.tempdir + "/" + self._out_file
        self._in_file = "pg%u_in.pcap" % self.pg_index
        self._in_path = self.test.tempdir + "/" + self._in_file
        self._capture_cli = "packet-generator capture pg%u pcap %s" % (
            self.pg_index, self.out_path)
        self._cap_name = "pcap%u-sw_if_index-%s" % (
            self.pg_index, self.sw_if_index)
        self._input_cli = \
            "packet-generator new pcap %s source pg%u name %s" % (
                self.in_path, self.pg_index, self.cap_name)
        self._nb_replays = None

    def _rename_previous_capture_file(self, path, counter, file):
        # if a file from a previous capture exists, rename it.
        try:
            if os.path.isfile(path):
                name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
                    (self.test.tempdir,
                     time.time(),
                     self.name,
                     counter,
                     file)
                self.test.logger.debug("Renaming %s->%s" %
                                       (path, name))
                os.rename(path, name)
        except OSError:
            self.test.logger.debug("OSError: Could not rename %s %s" %
                                   (path, file))

    def enable_capture(self):
        """ Enable capture on this packet-generator interface
            of at most n packets.
            If n < 0, this is no limit
        """
        # disable the capture to flush the capture
        self.disable_capture()
        self._rename_previous_capture_file(self.out_path,
                                           self.out_history_counter,
                                           self._out_file)
        # FIXME this should be an API, but no such exists atm
        self.test.vapi.cli(self.capture_cli)
        self._pcap_reader = None

    def disable_capture(self):
        self.test.vapi.cli("%s disable" % self.capture_cli)

    def add_stream(self, pkts, nb_replays=None, worker=None):
        """
        Add a stream of packets to this packet-generator

        :param pkts: iterable packets

        """
        self._worker = worker
        self._nb_replays = nb_replays
        self._rename_previous_capture_file(self.in_path,
                                           self.in_history_counter,
                                           self._in_file)
        wrpcap(self.in_path, pkts)
        self.test.register_capture(self.cap_name)
        # FIXME this should be an API, but no such exists atm
        self.test.vapi.cli(self.input_cli)

    def generate_debug_aid(self, kind):
        """ Create a hardlink to the out file with a counter and a file
        containing stack trace to ease debugging in case of multiple capture
        files present. """
        self.test.logger.debug("Generating debug aid for %s on %s" %
                               (kind, self._name))
        link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
                                 (self.test.tempdir, self._name,
                                  self._out_assert_counter, kind, suffix)
                                 for suffix in ["pcap", "stack"]
                                 ]
        os.link(self.out_path, link_path)
        with open(stack_path, "w") as f:
            f.writelines(format_stack())
        self._out_assert_counter += 1

    def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
        """ Helper method to get capture and filter it """
        try:
            if not self.wait_for_capture_file(timeout):
                return None
            output = rdpcap(self.out_path)
            self.test.logger.debug("Capture has %s packets" % len(output.res))
        except:
            self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
                                   (self.out_path, format_exc()))
            return None
        before = len(output.res)
        if filter_out_fn:
            output.res = [p for p in output.res if not filter_out_fn(p)]
        removed = before - len(output.res)
        if removed:
            self.test.logger.debug(
                "Filtered out %s packets from capture (returning %s)" %
                (removed, len(output.res)))
        return output

    def get_capture(self, expected_count=None, remark=None, timeout=1,
                    filter_out_fn=is_ipv6_misc):
        """ Get captured packets

        :param expected_count: expected number of packets to capture, if None,
                               then self.test.packet_count_for_dst_pg_idx is
                               used to lookup the expected count
        :param remark: remark printed into debug logs
        :param timeout: how long to wait for packets
        :param filter_out_fn: filter applied to each packet, packets for which
                              the filter returns True are removed from capture
        :returns: iterable packets
        """
        remaining_time = timeout
        capture = None
        name = self.name if remark is None else "%s (%s)" % (self.name, remark)
        based_on = "based on provided argument"
        if expected_count is None:
            expected_count = \
                self.test.get_packet_count_for_if_idx(self.sw_if_index)
            based_on = "based on stored packet_infos"
            if expected_count == 0:
                raise Exception(
                    "Internal error, expected packet count for %s is 0!" %
                    name)
        self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
            expected_count, based_on, name))
        while remaining_time > 0:
            before = time.time()
            capture = self._get_capture(remaining_time, filter_out_fn)
            elapsed_time = time.time() - before
            if capture:
                if len(capture.res) == expected_count:
                    # bingo, got the packets we expected
                    return capture
                elif len(capture.res) > expected_count:
                    self.test.logger.error(
                        ppc("Unexpected packets captured:", capture))
                    break
                else:
                    self.test.logger.debug("Partial capture containing %s "
                                           "packets doesn't match expected "
                                           "count %s (yet?)" %
                                           (len(capture.res), expected_count))
            elif expected_count == 0:
                # bingo, got None as we expected - return empty capture
                return PacketList()
            remaining_time -= elapsed_time
        if capture:
            self.generate_debug_aid("count-mismatch")
            raise Exception("Captured packets mismatch, captured %s packets, "
                            "expected %s packets on %s" %
                            (len(capture.res), expected_count, name))
        else:
            raise Exception("No packets captured on %s" % name)

    def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
        """ Assert that nothing unfiltered was captured on interface

        :param remark: remark printed into debug logs
        :param filter_out_fn: filter applied to each packet, packets for which
                              the filter returns True are removed from capture
        """
        if os.path.isfile(self.out_path):
            try:
                capture = self.get_capture(
                    0, remark=remark, filter_out_fn=filter_out_fn)
                if not capture or len(capture.res) == 0:
                    # junk filtered out, we're good
                    return
            except:
                pass
            self.generate_debug_aid("empty-assert")
            if remark:
                raise AssertionError(
                    "Non-empty capture file present for interface %s (%s)" %
                    (self.name, remark))
            else:
                raise AssertionError("Capture file present for interface %s" %
                                     self.name)

    def wait_for_pg_stop(self):
        # wait till packet-generator is stopped
        # "show packet-generator" while it is still running gives this:
        # Name               Enabled        Count     Parameters
        # pcap0-sw_if_inde     Yes           64       limit 64, ...
        #
        # also have a 5-minute timeout just in case things go terribly wrong...
        deadline = time.time() + 300
        while self.test.vapi.cli('show packet-generator').find("Yes") != -1:
            self._test.sleep(0.01)  # yield
            if time.time() > deadline:
                self.test.logger.debug("Timeout waiting for pg to stop")
                break

    def wait_for_capture_file(self, timeout=1):
        """
        Wait until pcap capture file appears

        :param timeout: How long to wait for the packet (default 1s)

        :returns: True/False if the file is present or appears within timeout
        """
        self.wait_for_pg_stop()
        deadline = time.time() + timeout
        if not os.path.isfile(self.out_path):
            self.test.logger.debug("Waiting for capture file %s to appear, "
                                   "timeout is %ss" % (self.out_path, timeout))
        else:
            self.test.logger.debug("Capture file %s already exists" %
                                   self.out_path)
            return True
        while time.time() < deadline:
            if os.path.isfile(self.out_path):
                break
            self._test.sleep(0)  # yield
        if os.path.isfile(self.out_path):
            self.test.logger.debug("Capture file appeared after %fs" %
                                   (time.time() - (deadline - timeout)))
        else:
            self.test.logger.debug("Timeout - capture file still nowhere")
            return False
        return True

    def verify_enough_packet_data_in_pcap(self):
        """
        Check if enough data is available in file handled by internal pcap
        reader so that a whole packet can be read.

        :returns: True if enough data present, else False
        """
        orig_pos = self._pcap_reader.f.tell()  # save file position
        enough_data = False
        # read packet header from pcap
        packet_header_size = 16
        caplen = None
        end_pos = None
        hdr = self._pcap_reader.f.read(packet_header_size)
        if len(hdr) == packet_header_size:
            # parse the capture length - caplen
            sec, usec, caplen, wirelen = struct.unpack(
                self._pcap_reader.endian + "IIII", hdr)
            self._pcap_reader.f.seek(0, 2)  # seek to end of file
            end_pos = self._pcap_reader.f.tell()  # get position at end
            if end_pos >= orig_pos + len(hdr) + caplen:
                enough_data = True  # yay, we have enough data
        self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
        return enough_data

    def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
        """
        Wait for next packet captured with a timeout

        :param timeout: How long to wait for the packet

        :returns: Captured packet if no packet arrived within timeout
        :raises Exception: if no packet arrives within timeout
        """
        deadline = time.time() + timeout
        if self._pcap_reader is None:
            if not self.wait_for_capture_file(timeout):
                raise CaptureTimeoutError("Capture file %s did not appear "
                                          "within timeout" % self.out_path)
            while time.time() < deadline:
                try:
                    self._pcap_reader = PcapReader(self.out_path)
                    break
                except:
                    self.test.logger.debug(
                        "Exception in scapy.PcapReader(%s): %s" %
                        (self.out_path, format_exc()))
        if not self._pcap_reader:
            raise CaptureTimeoutError("Capture file %s did not appear within "
                                      "timeout" % self.out_path)

        poll = False
        if timeout > 0:
            self.test.logger.debug("Waiting for packet")
        else:
            poll = True
            self.test.logger.debug("Polling for packet")
        while time.time() < deadline or poll:
            if not self.verify_enough_packet_data_in_pcap():
                self._test.sleep(0)  # yield
                poll = False
                continue
            p = self._pcap_reader.recv()
            if p is not None:
                if filter_out_fn is not None and filter_out_fn(p):
                    self.test.logger.debug(
                        "Packet received after %ss was filtered out" %
                        (time.time() - (deadline - timeout)))
                else:
                    self.test.logger.debug(
                        "Packet received after %fs" %
                        (time.time() - (deadline - timeout)))
                    return p
            self._test.sleep(0)  # yield
            poll = False
        self.test.logger.debug("Timeout - no packets received")
        raise CaptureTimeoutError("Packet didn't arrive within timeout")

    def create_arp_req(self):
        """Create ARP request applicable for this interface"""
        return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
                ARP(op=ARP.who_has, pdst=self.local_ip4,
                    psrc=self.remote_ip4, hwsrc=self.remote_mac))

    def create_ndp_req(self):
        """Create NDP - NS applicable for this interface"""
        nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
        d = inet_ntop(socket.AF_INET6, nsma)

        return (Ether(dst=in6_getnsmac(nsma)) /
                IPv6(dst=d, src=self.remote_ip6) /
                ICMPv6ND_NS(tgt=self.local_ip6) /
                ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))

    def resolve_arp(self, pg_interface=None):
        """Resolve ARP using provided packet-generator interface

        :param pg_interface: interface used to resolve, if None then this
            interface is used

        """
        if pg_interface is None:
            pg_interface = self
        self.test.logger.info("Sending ARP request for %s on port %s" %
                              (self.local_ip4, pg_interface.name))
        arp_req = self.create_arp_req()
        pg_interface.add_stream(arp_req)
        pg_interface.enable_capture()
        self.test.pg_start()
        self.test.logger.info(self.test.vapi.cli("show trace"))
        try:
            captured_packet = pg_interface.wait_for_packet(1)
        except:
            self.test.logger.info("No ARP received on port %s" %
                                  pg_interface.name)
            return
        arp_reply = captured_packet.copy()  # keep original for exception
        try:
            if arp_reply[ARP].op == ARP.is_at:
                self.test.logger.info("VPP %s MAC address is %s " %
                                      (self.name, arp_reply[ARP].hwsrc))
                self._local_mac = arp_reply[ARP].hwsrc
            else:
                self.test.logger.info("No ARP received on port %s" %
                                      pg_interface.name)
        except:
            self.test.logger.error(
                ppp("Unexpected response to ARP request:", captured_packet))
            raise

    def resolve_ndp(self, pg_interface=None, timeout=1):
        """Resolve NDP using provided packet-generator interface

        :param pg_interface: interface used to resolve, if None then this
            interface is used
        :param timeout: how long to wait for response before giving up

        """
        if pg_interface is None:
            pg_interface = self
        self.test.logger.info("Sending NDP request for %s on port %s" %
                              (self.local_ip6, pg_interface.name))
        ndp_req = self.create_ndp_req()
        pg_interface.add_stream(ndp_req)
        pg_interface.enable_capture()
        self.test.pg_start()
        now = time.time()
        deadline = now + timeout
        # Enabling IPv6 on an interface can generate more than the
        # ND reply we are looking for (namely MLD). So loop through
        # the replies to look for want we want.
        while now < deadline:
            try:
                captured_packet = pg_interface.wait_for_packet(
                    deadline - now, filter_out_fn=None)
            except:
                self.test.logger.error(
                    "Timeout while waiting for NDP response")
                raise
            ndp_reply = captured_packet.copy()  # keep original for exception
            try:
                ndp_na = ndp_reply[ICMPv6ND_NA]
                opt = ndp_na[ICMPv6NDOptDstLLAddr]
                self.test.logger.info("VPP %s MAC address is %s " %
                                      (self.name, opt.lladdr))
                self._local_mac = opt.lladdr
                self.test.logger.debug(self.test.vapi.cli("show trace"))
                # we now have the MAC we've been after
                return
            except:
                self.test.logger.info(
                    ppp("Unexpected response to NDP request:",
                        captured_packet))
            now = time.time()

        self.test.logger.debug(self.test.vapi.cli("show trace"))
        raise Exception("Timeout while waiting for NDP response")