X-Git-Url: https://git.exim.org/users/heiko/exim.git/blobdiff_plain/8255135bf80545a31493a83348a4e8da901a4768..cdb844d019f4100eaceee36a521e9a4811a354f1:/test/scripts/1990-TCP-Fast-Open/1990

diff --git a/test/scripts/1990-TCP-Fast-Open/1990 b/test/scripts/1990-TCP-Fast-Open/1990
index 3fffce2d4..1fc4682aa 100644
--- a/test/scripts/1990-TCP-Fast-Open/1990
+++ b/test/scripts/1990-TCP-Fast-Open/1990
@@ -8,30 +8,46 @@
 # option on the SYN, but the fast-output SMTP banner will not
 # be seen unless you also deliberately emulate a long path:
 # 'sudo tc qdisc add dev lo root netem delay 50ms'
+# You'll need iproute-tc installed, for the tc command.
 # You'll need kernel-modules-extra installed, or you get
 # an unhelpful error from RTNETLINK.
 # To tidy up:  'sudo tc qdisc delete dev lo root'
 #
+# MacOS:
+# The kernel seems to have TFO enabled both ways as default.
+# There is a net.inet.tcp.clear_tfocache parameter
+## sysctl -w foo-val
+#
+# For network delays there is something called 'Network Link Conditioner'
+# which might do the job.  But how to manipulate it?
+#
+#
 sudo perl
 system ("tc qdisc add dev lo root netem delay 50ms");
 ****
 #
+#
+# Disable the TFO blackhole detection, as we seem to be running foul of it.
+# If bitten, we see the expected EINPROGRESS for sendto, yet no TFO cookie
+# option on the SYN.
+#
+sudo perl
+system ("[ -e /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec ] && echo 0 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
+****
+#
 # First time runs will see a TFO request option only; subsequent
 # ones should see the TFO cookie and fast-output SMTP banner
 # (currently on a separate packet after the server SYN,ACK but before
 # the client ACK).
 #
-# The client log => lint.ex  should have a "TFO" element.
-# Assuming this is the first run since boot, the a@test recipient will not.
+# The client log => line  should have a "TFO" element.
+# The server log <= line for a@test.ex  should not.
 #
+# First clear any previously-obtained cookie:
 sudo perl
 system ("ip tcp_metrics delete 127.0.0.1");
 ****
 #
-# The server log <= line for b@test.ex  should have a "TFO" element, but
-# this will only be obtained when the above delay is inserted into the
-# loopback net path.
-#
 #
 #
 # FreeBSD: it looks like you have to compile a custom kernel, with
@@ -47,6 +63,10 @@ Testing
 ****
 sleep 3
 #
+# The server log <= line for b@test.ex  should have a "TFO" element, but
+# this will only be obtained when the above delay is inserted into the
+# loopback net path.
+#
 exim b@test.ex
 Testing
 ****
@@ -55,6 +75,7 @@ sleep 3
 #
 sudo perl
 system ("tc qdisc delete dev lo root");
+system ("[ -e /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec ] && echo 3600 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
 ****
 #
 killdaemon