test/scripts/1990-TCP-Fast-Open/1990

   1 # TCP Fast Open
   2 #
   3 # Linux:
   4 # Both server and client-side TFO support must be enabled in the
   5 # kernel, 'sudo sh -c "echo 3 > /proc/sys/net/ipv4/tcp_fastopen"'.
   6 #
   7 # A packet capture on the loopback interface will show the TFO
   8 # option on the SYN, but the fast-output SMTP banner will not
   9 # be seen unless you also deliberately emulate a long path:
  10 # 'sudo tc qdisc add dev lo root netem delay 100ms'
  11 # You'll need kernel-modules-extra installed, or you get
  12 # an unhelpful error from RTNETLINK.
  13 # To tidy up:  'sudo tc qdisc delete dev lo root'
  14 #
  15 # First time runs will see a TFO request option only; subsequent
  16 # ones should see the TFO cookie and fast-output SMTP banner
  17 # (currently on a separate packet after the server SYN,ACK but before
  18 # the client ACK).
  19 #
  20 # The client log => lint.ex  should have a "TFO" element.
  21 # Assuming this is the first run since boot, the a@test recipient will not.
  22 #
  23 # The server log <= line for b@test.ex  should have a "TFO" element, but
  24 # this will only be obtained when the above delay is inserted into the
  25 # loopback net path.
  26 #
  27 # this attempt to tidy up does not work
  28 #sudo perl
  29 #open (my $fh, "/proc/sys/net/ipv4/tcp_fastopen_key");
  30 #print $fh "00000000-00000000-00000000-00000000";
  31 #close $fh;
  32 #****
  33 #
  34 #
  35 # FreeBSD: it looks like you have to compile a custom kernel, with
  36 # 'options TCP_RFC7413' in the config.  Also set
  37 # 'net.inet.tcp.fastopen.enabled=1' in /etc/sysctl.conf
  38 # Untested.
  39 #
  40 exim -DSERVER=server -bd -oX PORT_D
  41 ****
  42 #
  43 exim a@test.ex
  44 Testing
  45 ****
  46 sleep 3
  47 #
  48 exim b@test.ex
  49 Testing
  50 ****
  51 sleep 3
  52 #
  53 killdaemon
  54 no_msglog_check