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#!/usr/bin/python3
#
# Copyright 2017 The Android Open Source Project
#
# 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.
import unittest
from errno import *
from socket import *
from scapy import all as scapy
import multinetwork_base
import net_test
import os
import packets
import tcp_metrics
TCPOPT_FASTOPEN = 34
TCP_FASTOPEN_CONNECT = 30
BH_TIMEOUT_SYSCTL = "/proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec"
class TcpFastOpenTest(multinetwork_base.MultiNetworkBaseTest):
@classmethod
def setUpClass(cls):
super(TcpFastOpenTest, cls).setUpClass()
cls.tcp_metrics = tcp_metrics.TcpMetrics()
def TFOClientSocket(self, version, netid):
s = net_test.TCPSocket(net_test.GetAddressFamily(version))
net_test.DisableFinWait(s)
self.SelectInterface(s, netid, "mark")
s.setsockopt(IPPROTO_TCP, TCP_FASTOPEN_CONNECT, 1)
return s
def assertSocketNotConnected(self, sock):
self.assertRaisesErrno(ENOTCONN, sock.getpeername)
def assertSocketConnected(self, sock):
sock.getpeername() # No errors? Socket is alive and connected.
def clearTcpMetrics(self, version, netid):
saddr = self.MyAddress(version, netid)
daddr = self.GetRemoteAddress(version)
self.tcp_metrics.DelMetrics(saddr, daddr)
with self.assertRaisesErrno(ESRCH):
print(self.tcp_metrics.GetMetrics(saddr, daddr))
def assertNoTcpMetrics(self, version, netid):
saddr = self.MyAddress(version, netid)
daddr = self.GetRemoteAddress(version)
with self.assertRaisesErrno(ENOENT):
self.tcp_metrics.GetMetrics(saddr, daddr)
def clearBlackhole(self):
timeout = self.GetSysctl(BH_TIMEOUT_SYSCTL)
# Write to timeout to clear any pre-existing blackhole condition
self.SetSysctl(BH_TIMEOUT_SYSCTL, timeout)
def CheckConnectOption(self, version):
ip_layer = {4: scapy.IP, 6: scapy.IPv6}[version]
netid = self.RandomNetid()
s = self.TFOClientSocket(version, netid)
self.clearTcpMetrics(version, netid)
self.clearBlackhole()
# Connect the first time.
remoteaddr = self.GetRemoteAddress(version)
with self.assertRaisesErrno(EINPROGRESS):
s.connect((remoteaddr, 53))
self.assertSocketNotConnected(s)
# Expect a SYN handshake with an empty TFO option.
myaddr = self.MyAddress(version, netid)
port = s.getsockname()[1]
self.assertNotEqual(0, port)
desc, syn = packets.SYN(53, version, myaddr, remoteaddr, port, seq=None)
syn.getlayer("TCP").options = [(TCPOPT_FASTOPEN, "")]
msg = "Fastopen connect: expected %s" % desc
syn = self.ExpectPacketOn(netid, msg, syn)
syn = ip_layer(bytes(syn))
# Receive a SYN+ACK with a TFO cookie and expect the connection to proceed
# as normal.
desc, synack = packets.SYNACK(version, remoteaddr, myaddr, syn)
synack.getlayer("TCP").options = [
(TCPOPT_FASTOPEN, "helloT"), ("NOP", None), ("NOP", None)]
self.ReceivePacketOn(netid, synack)
synack = ip_layer(bytes(synack))
desc, ack = packets.ACK(version, myaddr, remoteaddr, synack)
msg = "First connect: got SYN+ACK, expected %s" % desc
self.ExpectPacketOn(netid, msg, ack)
self.assertSocketConnected(s)
s.close()
desc, rst = packets.RST(version, myaddr, remoteaddr, synack)
msg = "Closing client socket, expecting %s" % desc
self.ExpectPacketOn(netid, msg, rst)
# Connect to the same destination again. Expect the connect to succeed
# without sending a SYN packet.
s = self.TFOClientSocket(version, netid)
s.connect((remoteaddr, 53))
self.assertSocketNotConnected(s)
self.ExpectNoPacketsOn(netid, "Second TFO connect, expected no packets")
# Issue a write and expect a SYN with data.
port = s.getsockname()[1]
s.send(net_test.UDP_PAYLOAD)
desc, syn = packets.SYN(53, version, myaddr, remoteaddr, port, seq=None)
t = syn.getlayer(scapy.TCP)
t.options = [ (TCPOPT_FASTOPEN, "helloT"), ("NOP", None), ("NOP", None)]
t.payload = scapy.Raw(net_test.UDP_PAYLOAD)
msg = "TFO write, expected %s" % desc
self.ExpectPacketOn(netid, msg, syn)
s.close()
def testConnectOptionIPv4(self):
self.CheckConnectOption(4)
def testConnectOptionIPv6(self):
self.CheckConnectOption(6)
if __name__ == "__main__":
unittest.main()
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