Add a regression test for the changes in r359922 and r359923.

Note that the Python code has been tested on both Python 2.7 and 3.7.

Reviewed by:	olivier
MFC after:	2 weeks
Sponsored by:	Netflix, Inc.

tests/sys/kern/Makefile

@@ -1,5 +1,7 @@
 # $FreeBSD$
 
+PACKAGE=	tests
+
 TESTSRC=	${SRCTOP}/contrib/netbsd-tests/kernel
 .PATH:		${SRCTOP}/sys/kern
 
@@ -24,6 +26,12 @@ ATF_TESTS_C+=	waitpid_nohang
 ATF_TESTS_C+=	pdeathsig
 
 ATF_TESTS_SH+=	coredump_phnum_test
+ATF_TESTS_SH+=	sonewconn_overflow
+TEST_METADATA.sonewconn_overflow+=	required_programs="python"
+TEST_METADATA.sonewconn_overflow+=	required_user="root"
+
+${PACKAGE}FILES+=	sonewconn_overflow.py
+${PACKAGE}FILESMODE_sonewconn_overflow.py=0555
 
 BINDIR=		${TESTSDIR}
 PROGS+=		coredump_phnum_helper

tests/sys/kern/sonewconn_overflow.py

@@ -0,0 +1,156 @@
+#!/usr/bin/env python
+#-
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2020 Netflix, Inc.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $FreeBSD$
+#
+
+import socket
+import os
+import sys
+from subprocess import check_output
+from time import sleep
+
+V4HOST = '127.0.0.1'
+V6HOST = '::1'
+TCPPORT = 65432
+UNIXSOCK = '/tmp/testsock'
+TYPE = socket.SOCK_STREAM
+
+class GenericTest(object):
+    def __init__(self):
+        raise NotImplementedError("Subclass must override the __init__ method")
+    def setup(self, af, addr):
+        self.sockets = []
+        self.ls = None
+        self.ls = socket.socket(af, TYPE)
+        self.ls.bind(addr)
+        self.ls.listen(2)
+        self.af = af
+        self.addr = addr
+    def doTest(self, cnt):
+        rv = 0
+        for i in range(0, cnt):
+            try:
+                s = socket.socket(self.af, TYPE)
+                s.connect(self.addr)
+            except:
+                continue
+            self.sockets.append(s)
+            rv += 1
+        return rv
+    def __del__(self):
+        for s in self.sockets:
+            s.close()
+        if self.ls is not None:
+            self.ls.close()
+
+class IPv4Test(GenericTest):
+    def __init__(self):
+        super(IPv4Test, self).setup(socket.AF_INET, (V4HOST, TCPPORT))
+
+class IPv6Test(GenericTest):
+    def __init__(self):
+        super(IPv6Test, self).setup(socket.AF_INET6, (V6HOST, TCPPORT))
+
+class UnixTest(GenericTest):
+    def __init__(self):
+        super(UnixTest, self).setup(socket.AF_UNIX, UNIXSOCK)
+    def __del__(self):
+        super(UnixTest, self).__del__()
+        os.remove(UNIXSOCK)
+
+class LogChecker():
+    def __init__(self):
+        # Figure out how big the dmesg buffer is.
+        self.dmesgOff = len(check_output("/sbin/dmesg"))
+
+    def checkForMsg(self, expected):
+        newOff = self.dmesgOff
+        for i in range(0, 3):
+            dmesg = check_output("/sbin/dmesg")
+            newOff = len(dmesg)
+            if newOff >= self.dmesgOff:
+                dmesg = dmesg[self.dmesgOff:]
+            for line in dmesg.splitlines():
+                try:
+                    if str(line).find(expected) >= 0:
+                        self.dmesgOff = newOff
+                        return True
+                except:
+                    pass
+            sleep(0.5)
+        self.dmesgOff = newOff
+        return False
+
+def main():
+    ip4 = IPv4Test()
+    ip6 = IPv6Test()
+    lcl = UnixTest()
+    lc = LogChecker()
+    failure = False
+
+    STDLOGMSG = "Listen queue overflow: 4 already in queue awaiting acceptance (1 occurrences)"
+
+    V4LOGMSG = "(%s:%d (proto 6)): %s" % (V4HOST, TCPPORT, STDLOGMSG)
+    ip4.doTest(5)
+    if not lc.checkForMsg(V4LOGMSG):
+        failure = True
+        sys.stderr.write("IPv4 log message not seen\n")
+    else:
+        ip4.doTest(1)
+        if lc.checkForMsg(V4LOGMSG):
+            failure = True
+            sys.stderr.write("Subsequent IPv4 log message not suppressed\n")
+
+    V6LOGMSG = "([%s]:%d (proto 6)): %s" % (V6HOST, TCPPORT, STDLOGMSG)
+    ip6.doTest(5)
+    if not lc.checkForMsg(V6LOGMSG):
+        failure = True
+        sys.stderr.write("IPv6 log message not seen\n")
+    else:
+        ip6.doTest(1)
+        if lc.checkForMsg(V6LOGMSG):
+            failure = True
+            sys.stderr.write("Subsequent IPv6 log message not suppressed\n")
+
+    UNIXLOGMSG = "(local:%s): %s" % (UNIXSOCK, STDLOGMSG)
+    lcl.doTest(5)
+    if not lc.checkForMsg(UNIXLOGMSG):
+        failure = True
+        sys.stderr.write("Unix socket log message not seen\n")
+    else:
+        lcl.doTest(1)
+        if lc.checkForMsg(UNIXLOGMSG):
+            failure = True
+            sys.stderr.write("Subsequent Unix socket log message not suppressed\n")
+
+    if failure:
+        sys.exit(1)
+    sys.exit(0)
+
+if __name__ == '__main__':
+    main()

tests/sys/kern/sonewconn_overflow.sh

@@ -0,0 +1,43 @@
+# $FreeBSD$
+#-
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2020 Netflix, Inc.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+atf_test_case sonewconn_overflow_01
+sonewconn_overflow_01_head()
+{
+	atf_set descr "Check the operation of the sonewconn() listen queue overflow messages"
+}
+
+sonewconn_overflow_01_body()
+{
+	atf_check -s exit:0 $(atf_get_srcdir)/sonewconn_overflow.py
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case sonewconn_overflow_01
+}