pf: Implement the NAT source port selection of MAP-E Customer Edge

MAP-E (RFC 7597) requires special care for selecting source ports
in NAT operation on the Customer Edge because a part of bits of the port
numbers are used by the Border Relay to distinguish another side of the
IPv4-over-IPv6 tunnel.

PR:		254577
Reviewed by:	kp
Differential Revision:	https://reviews.freebsd.org/D29468

(cherry picked from commit 2aa21096c7349390f22aa5d06b373a575baed1b4)

2 files changed, 92 insertions, 0 deletions

diff --git a/tests/sys/netpfil/pf/Makefile b/tests/sys/netpfil/pf/Makefile
index e422da3b9e3d..d2dbbcdd18f6 100644
--- a/tests/sys/netpfil/pf/Makefile
+++ b/tests/sys/netpfil/pf/Makefile
@@ -12,6 +12,7 @@ ATF_TESTS_SH+=	anchor \
 		fragmentation \
 		icmp \
 		killstate \
+		map_e \
 		names \
 		nat \
 		pass_block \
diff --git a/tests/sys/netpfil/pf/map_e.sh b/tests/sys/netpfil/pf/map_e.sh
new file mode 100644
index 000000000000..cc68fe26be5e
--- /dev/null
+++ b/tests/sys/netpfil/pf/map_e.sh
@@ -0,0 +1,91 @@
+# $FreeBSD$
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2021 KUROSAWA Takahiro <takahiro.kurosawa@gmail.com>
+#
+# 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.
+
+. $(atf_get_srcdir)/utils.subr
+
+atf_test_case "map_e" "cleanup"
+map_e_head()
+{
+	atf_set descr 'map-e-portset test'
+	atf_set require.user root
+}
+
+map_e_body()
+{
+	NC_TRY_COUNT=12
+
+	pft_init
+
+	epair_map_e=$(vnet_mkepair)
+	epair_echo=$(vnet_mkepair)
+
+	vnet_mkjail map_e ${epair_map_e}b ${epair_echo}a
+	vnet_mkjail echo ${epair_echo}b
+
+	ifconfig ${epair_map_e}a 192.0.2.2/24 up
+	route add -net 198.51.100.0/24 192.0.2.1
+
+	jexec map_e ifconfig ${epair_map_e}b 192.0.2.1/24 up
+	jexec map_e ifconfig ${epair_echo}a 198.51.100.1/24 up
+	jexec map_e sysctl net.inet.ip.forwarding=1
+
+	jexec echo ifconfig ${epair_echo}b 198.51.100.2/24 up
+	jexec echo /usr/sbin/inetd -p inetd-echo.pid $(atf_get_srcdir)/echo_inetd.conf
+
+	# Enable pf!
+	jexec map_e pfctl -e
+	pft_set_rules map_e \
+		"nat pass on ${epair_echo}a inet from 192.0.2.0/24 to any -> (${epair_echo}a) map-e-portset 2/12/0x342"
+
+	# Only allow specified ports.
+	jexec echo pfctl -e
+	pft_set_rules echo "block return all" \
+		"pass in on ${epair_echo}b inet proto tcp from 198.51.100.1 port 19720:19723 to (${epair_echo}b) port 7" \
+		"pass in on ${epair_echo}b inet proto tcp from 198.51.100.1 port 36104:36107 to (${epair_echo}b) port 7" \
+		"pass in on ${epair_echo}b inet proto tcp from 198.51.100.1 port 52488:52491 to (${epair_echo}b) port 7"
+
+	i=0
+	while [ ${i} -lt ${NC_TRY_COUNT} ]
+	do
+		echo "foo ${i}" | timeout 2 nc -N 198.51.100.2 7
+		if [ $? -ne 0 ]; then
+			atf_fail "nc failed (${i})"
+		fi
+		i=$((${i}+1))
+	done
+}
+
+map_e_cleanup()
+{
+	rm -f inetd-echo.pid
+	pft_cleanup
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case "map_e"
+}