REGTESTS: log: check that a log-forward TCP session ends on client close

This test covers the bug fixed by the previous commit:

    BUG/MEDIUM: log: do not ignore the peer's shutdown in the syslog applet

A log-forward section without "timeout client" accepts a single
connection at a time ("maxconn 1"). A first client sends a message and
only closes once the message was forwarded, so that its shutdown is
received alone, on an empty input buffer. A second client then sends
another message, which can only be forwarded once the first session is
gone. On an affected, unpatched build, the first session never ends and
the test fails on its timeout. It passes on 3.2, which is not affected.

This must be backported wherever the fix above is backported.

diff --git a/reg-tests/log/log_forward_tcp_close.vtc b/reg-tests/log/log_forward_tcp_close.vtc
new file mode 100644 (file)
index 0000000..e53b63e
--- /dev/null
+++ b/reg-tests/log/log_forward_tcp_close.vtc
@@ -0,0 +1,60 @@
+varnishtest "log-forward: a TCP syslog session ends when the client closes"
+
+# A TCP syslog session of a log-forward section must end once the client
+# closes its connection. Since 5da704b55 ("MEDIUM: log: Update the log applet
+# to use its own buffers"), the shutdown was ignored when it was received
+# alone, on an empty input buffer. The session then stayed until "timeout
+# client", and forever without one, as in the section below.
+#
+# The section accepts a single connection at a time ("maxconn 1"). The first
+# client sends a message and only closes once that message was forwarded, so
+# its shutdown is received alone. The message of the second client can only
+# be forwarded once the first session is gone. If that session never ends,
+# Slg2 never gets the second message and the test fails on its timeout.
+
+feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(2.3-dev1)'"
+feature ignore_unknown_macro
+
+barrier b1 cond 2
+
+# Slg1 tells when the first message was forwarded, Slg2 gets both messages
+syslog Slg1 -level info {
+    recv
+    expect ~ "first message"
+} -start
+
+syslog Slg2 -level info {
+    recv
+    expect ~ "first message"
+    recv
+    expect ~ "second message"
+} -start
+
+haproxy h1 -conf {
+    global
+    .if feature(THREAD)
+        thread-groups 1
+    .endif
+
+    log-forward syslog-tcp
+        maxconn 1
+        bind "fd@${lf}"
+        log ${Slg1_addr}:${Slg1_port} local0
+        log ${Slg2_addr}:${Slg2_port} local0
+} -start
+
+client c1 -connect ${h1_lf_sock} {
+    send "<134>1 2026-10-06T00:00:00Z host app - - - first message\n"
+    # do not close before the message was forwarded
+    barrier b1 sync
+} -start
+
+syslog Slg1 -wait
+barrier b1 sync
+client c1 -wait
+
+client c2 -connect ${h1_lf_sock} {
+    send "<134>1 2026-10-06T00:00:01Z host app - - - second message\n"
+} -run
+
+syslog Slg2 -wait