tests: add test for ipfw fwd localaddr,port

Checks basic forward to local address, also with presence of
a listener that matches original port (see aab8c844b9). Based
on non-ATF test case written by Pavel Polyakov.

Reviewed by:		kp, melifaro
Differential revision:	https://reviews.freebsd.org/D37960

etc/mtree/BSD.tests.dist

@@ -835,6 +835,8 @@
         netpfil
             common
             ..
+            ipfw
+            ..
             pf
                 ioctl
                 ..

tests/sys/netpfil/Makefile

@@ -9,4 +9,8 @@ TESTS_SUBDIRS+=		common
 TESTS_SUBDIRS+=		pf
 .endif
 
+.if ${MK_IPFW} != "no"
+TESTS_SUBDIRS+=		ipfw
+.endif
+
 .include <bsd.test.mk>

tests/sys/netpfil/ipfw/Makefile

@@ -0,0 +1,8 @@
+PACKAGE=	tests
+
+TESTSDIR=       ${TESTSBASE}/sys/netpfil/ipfw
+
+ATF_TESTS_SH+=	fwd
+${PACKAGE}FILES+=	fwd_inetd.conf
+
+.include <bsd.test.mk>

tests/sys/netpfil/ipfw/fwd.sh

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2022 Gleb Smirnoff <glebius@FreeBSD.org>
+# Copyright (c) 2022 Pavel Polyakov <bsd@kobyla.org>
+#
+# 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.
+
+. $(atf_get_srcdir)/../common/utils.subr
+
+atf_test_case "local" "cleanup"
+local_head()
+{
+	atf_set descr 'Test that fwd 127.0.0.1,port works'
+	atf_set require.user root
+}
+
+local_body()
+{
+	firewall_init "ipfw"
+
+	epair=$(vnet_mkepair)
+	vnet_mkjail alcatraz ${epair}b
+
+	ifconfig ${epair}a 192.0.2.0/31 up
+	route add 192.0.2.3/32 192.0.2.1
+
+	jexec alcatraz ifconfig lo0 127.0.0.1/8 up
+	jexec alcatraz ifconfig ${epair}b 192.0.2.1/31 up
+	jexec alcatraz route add default 192.0.2.0
+	jexec alcatraz /usr/sbin/inetd -p /dev/null $(atf_get_srcdir)/fwd_inetd.conf
+
+	firewall_config alcatraz ipfw ipfw \
+	    "ipfw add 10 fwd 127.0.0.1,82 tcp from any to any dst-port 80 in via ${epair}b" \
+	    "ipfw add 20 allow all from any to any"
+
+	# Sanity check
+	atf_check -s exit:0 -o ignore ping -i .1 -c 3 -s 1200 192.0.2.1
+
+	reply=$(nc -nN 192.0.2.3 80 < /dev/null)
+	atf_check [ "${reply}" = "GOOD 82" ]
+}
+
+local_cleanup()
+{
+	firewall_cleanup $1
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case "local"
+}

tests/sys/netpfil/ipfw/fwd_inetd.conf

@@ -0,0 +1,6 @@
+#
+# Set up the correct listener and a listener that matches the original
+# destination port in the test, to check the bug fixed by aab8c844b91.
+#
+http	stream tcp nowait nobody /bin/echo	echo BAD 80
+xfer	stream tcp nowait nobody /bin/echo	echo GOOD 82