net/rds/test.py

#! /usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0
"""
This module provides functional testing for the net/rds component.
"""

import argparse
import ctypes
import errno
import hashlib
import os
import select
import signal
import socket
import subprocess
import sys

# Allow utils module to be imported from different directory
this_dir = os.path.dirname(os.path.realpath(__file__))
sys.path.append(os.path.join(this_dir, "../"))
# pylint: disable-next=wrong-import-position,import-error,no-name-in-module
from lib.py.utils import ip # noqa: E402
# pylint: disable-next=wrong-import-position,import-error,no-name-in-module
from lib.py.ksft import ksft_pr # noqa: E402

libc = ctypes.cdll.LoadLibrary('libc.so.6')
setns = libc.setns

NET0 = 'net0'
NET1 = 'net1'

VETH0 = 'veth0'
VETH1 = 'veth1'

# Helper function for creating a socket inside a network namespace.
# We need this because otherwise RDS will detect that the two TCP
# sockets are on the same interface and use the loop transport instead
# of the TCP transport.
def netns_socket(netns, *sock_args):
    """
    Creates sockets inside of network namespace

    :param netns: the name of the network namespace
    :param sock_args: socket family and type
    """
    u0, u1 = socket.socketpair(socket.AF_UNIX, socket.SOCK_SEQPACKET)

    child = os.fork()
    if child == 0:
        # change network namespace
        with open(f'/var/run/netns/{netns}', encoding='utf-8') as f:
            try:
                setns(f.fileno(), 0)
            except IOError as e:
                print(e.errno)
                print(e)

        # create socket in target namespace
        sock = socket.socket(*sock_args)

        # send resulting socket to parent
        socket.send_fds(u0, [], [sock.fileno()])

        os._exit(0)

    # receive socket from child
    _, fds, _, _ = socket.recv_fds(u1, 0, 1)
    os.waitpid(child, 0)
    u0.close()
    u1.close()
    return socket.fromfd(fds[0], *sock_args)

def stop_pcaps():
    """Stop tcpdump processes.

    We use pop() here to drain the list in the event that the test
    completes after the signal handler is fired.  List will be empty
    if logdir is not set
    """
    ksft_pr("Stopping network packet captures")
    while tcpdump_procs:
        proc = tcpdump_procs.pop()
        proc.terminate()
        try:
            proc.wait(timeout=5)
        except subprocess.TimeoutExpired:
            proc.kill()
            proc.wait()

def signal_handler(_sig, _frame):
    """
    Test timed out signal handler
    """
    ksft_pr("Test timed out")
    stop_pcaps()
    print("not ok 1 rds selftest")
    sys.exit(1)

#Parse out command line arguments.  We take an optional
# timeout parameter and an optional log output folder
parser = argparse.ArgumentParser(description="init script args",
                  formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument("-d", "--logdir", action="store",
                    help="directory to store logs", default=None)
parser.add_argument('-t', '--timeout', help="timeout to terminate hung test",
                    type=int, default=0)
parser.add_argument('-l', '--loss', help="Simulate tcp packet loss",
                    type=int, default=0)
parser.add_argument('-c', '--corruption', help="Simulate tcp packet corruption",
                    type=int, default=0)
parser.add_argument('-u', '--duplicate', help="Simulate tcp packet duplication",
                    type=int, default=0)
args = parser.parse_args()
logdir=args.logdir
PACKET_LOSS=str(args.loss)+'%'
PACKET_CORRUPTION=str(args.corruption)+'%'
PACKET_DUPLICATE=str(args.duplicate)+'%'

ip(f"netns add {NET0}")
ip(f"netns add {NET1}")
ip("link add type veth")

addrs = [
    # we technically don't need different port numbers, but this will
    # help identify traffic in the network analyzer
    ('10.0.0.1', 10000),
    ('10.0.0.2', 20000),
]

# move interfaces to separate namespaces so they can no longer be
# bound directly; this prevents rds from switching over from the tcp
# transport to the loop transport.
ip(f"link set {VETH0} netns {NET0} up")
ip(f"link set {VETH1} netns {NET1} up")


# add addresses
ip(f"-n {NET0} addr add {addrs[0][0]}/32 dev {VETH0}")
ip(f"-n {NET1} addr add {addrs[1][0]}/32 dev {VETH1}")

# add routes
ip(f"-n {NET0} route add {addrs[1][0]}/32 dev {VETH0}")
ip(f"-n {NET1} route add {addrs[0][0]}/32 dev {VETH1}")

# sanity check that our two interfaces/addresses are correctly set up
# and communicating by doing a single ping
ip(f"netns exec {NET0} ping -c 1 {addrs[1][0]}")

tcpdump_procs = []
# Start a packet capture on each network
if logdir is not None:
    for net in [NET0, NET1]:
        pcap = logdir+'/'+net+'.pcap'

        tcpdump_cmd = ['ip', 'netns', 'exec', net, '/usr/sbin/tcpdump']
        sudo_user = os.environ.get('SUDO_USER')
        if sudo_user:
            tcpdump_cmd.extend(['-Z', sudo_user])
        tcpdump_cmd.extend(['-i', 'any', '-w', pcap])

        # pylint: disable-next=consider-using-with
        p = subprocess.Popen(tcpdump_cmd,
                             stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
        tcpdump_procs.append(p)

# simulate packet loss, duplication and corruption
for net, iface in [(NET0, VETH0), (NET1, VETH1)]:
    ip(f"netns exec {net} /usr/sbin/tc qdisc add dev {iface} root netem  \
         corrupt {PACKET_CORRUPTION} loss {PACKET_LOSS} duplicate  \
         {PACKET_DUPLICATE}")

print("TAP version 13")
print("1..1")

# add a timeout
if args.timeout > 0:
    signal.alarm(args.timeout)
    signal.signal(signal.SIGALRM, signal_handler)

sockets = [
    netns_socket(NET0, socket.AF_RDS, socket.SOCK_SEQPACKET),
    netns_socket(NET1, socket.AF_RDS, socket.SOCK_SEQPACKET),
]

for s, addr in zip(sockets, addrs):
    s.bind(addr)
    s.setblocking(0)

fileno_to_socket = {
    s.fileno(): s for s in sockets
}

addr_to_socket = dict(zip(addrs, sockets))

socket_to_addr = {
    s: addr for addr, s in zip(addrs, sockets)
}

send_hashes = {}
recv_hashes = {}

ep = select.epoll()

for s in sockets:
    ep.register(s, select.EPOLLRDNORM)

NUM_PACKETS = 50000
nr_send = 0
nr_recv = 0

while nr_send < NUM_PACKETS:
    # Send as much as we can without blocking
    ksft_pr("sending...", nr_send, nr_recv)
    while nr_send < NUM_PACKETS:
        send_data = hashlib.sha256(
            f'packet {nr_send}'.encode('utf-8')).hexdigest().encode('utf-8')

        # pseudo-random send/receive pattern
        sender = sockets[nr_send % 2]
        receiver = sockets[1 - (nr_send % 3) % 2]

        try:
            sender.sendto(send_data, socket_to_addr[receiver])
            send_hashes.setdefault((sender.fileno(), receiver.fileno()),
                    hashlib.sha256()).update(f'<{send_data}>'.encode('utf-8'))
            nr_send = nr_send + 1
        except BlockingIOError:
            break
        except OSError as e:
            if e.errno in [errno.ENOBUFS, errno.ECONNRESET, errno.EPIPE]:
                break
            raise

    # Receive as much as we can without blocking
    ksft_pr("receiving...", nr_send, nr_recv)
    while nr_recv < nr_send:
        for fileno, eventmask in ep.poll():
            receiver = fileno_to_socket[fileno]

            if eventmask & select.EPOLLRDNORM:
                while True:
                    try:
                        recv_data, address = receiver.recvfrom(1024)
                        sender = addr_to_socket[address]
                        recv_hashes.setdefault((sender.fileno(),
                            receiver.fileno()), hashlib.sha256()).update(
                                    f'<{recv_data}>'.encode('utf-8'))
                        nr_recv = nr_recv + 1
                    except BlockingIOError:
                        break

    # exercise net/rds/tcp.c:rds_tcp_sysctl_reset()
    for net in [NET0, NET1]:
        ip(f"netns exec {net} /usr/sbin/sysctl net.rds.tcp.rds_tcp_rcvbuf=10000")
        ip(f"netns exec {net} /usr/sbin/sysctl net.rds.tcp.rds_tcp_sndbuf=10000")

ksft_pr("done", nr_send, nr_recv)

# the Python socket module doesn't know these
RDS_INFO_FIRST = 10000
RDS_INFO_LAST = 10017

nr_success = 0
nr_error = 0

for s in sockets:
    for optname in range(RDS_INFO_FIRST, RDS_INFO_LAST + 1):
        # Sigh, the Python socket module doesn't allow us to pass
        # buffer lengths greater than 1024 for some reason. RDS
        # wants multiple pages.
        try:
            s.getsockopt(socket.SOL_RDS, optname, 1024)
            nr_success = nr_success + 1
        except OSError as e:
            nr_error = nr_error + 1
            if e.errno == errno.ENOSPC:
                # ignore
                pass

ksft_pr(f"getsockopt(): {nr_success}/{nr_error}")
stop_pcaps()

# We're done sending and receiving stuff, now let's check if what
# we received is what we sent.
ret = 0
for (sender, receiver), send_hash in send_hashes.items():
    recv_hash = recv_hashes.get((sender, receiver))

    if recv_hash is None:
        ksft_pr("FAIL: No data received")
        ret = 1
        break

    if send_hash.hexdigest() != recv_hash.hexdigest():
        ksft_pr("FAIL: Send/recv mismatch")
        ksft_pr("hash expected:", send_hash.hexdigest())
        ksft_pr("hash received:", recv_hash.hexdigest())
        ret = 1
        break

    ksft_pr(f"{sender}/{receiver}: ok")

if ret == 0:
    ksft_pr("Success")
    print("ok 1 rds selftest")
else:
    print("not ok 1 rds selftest")

ksft_pr(f"Totals: pass:{1-ret} fail:{ret} skip:0")
sys.exit(ret)