Index: head/tests/sys/netinet/Makefile
===================================================================
--- head/tests/sys/netinet/Makefile
+++ head/tests/sys/netinet/Makefile
@@ -9,7 +9,7 @@
 		so_reuseport_lb_test \
 		socket_afinet
 
-ATF_TESTS_SH=	fibs_test redirect divert forward output
+ATF_TESTS_SH=	carp fibs_test redirect divert forward output
 
 PROGS=	udp_dontroute tcp_user_cookie
 
Index: head/tests/sys/netinet/carp.sh
===================================================================
--- head/tests/sys/netinet/carp.sh
+++ head/tests/sys/netinet/carp.sh
@@ -0,0 +1,152 @@
+# $FreeBSD$
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2020 Kristof Provost <kp@FreeBSD.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/vnet.subr
+
+is_master()
+{
+	jail=$1
+	itf=$2
+
+	jexec ${jail} ifconfig ${itf} | grep carp | grep MASTER
+}
+
+wait_for_carp()
+{
+	jail1=$1
+	itf1=$2
+	jail2=$3
+	itf2=$4
+
+	while [ -z "$(is_master ${jail1} ${itf1})" ] &&
+	    [ -z "$(is_master ${jail2} ${itf2})" ]; do
+		sleep 1
+	done
+}
+
+atf_test_case "basic_v4" "cleanup"
+basic_v4_head()
+{
+	atf_set descr 'Basic CARP test (IPv4)'
+	atf_set require.user root
+}
+
+basic_v4_body()
+{
+	if ! kldstat -q -m carp; then
+		atf_skip "This test requires carp"
+	fi
+
+	vnet_init
+	bridge=$(vnet_mkbridge)
+	epair_one=$(vnet_mkepair)
+	epair_two=$(vnet_mkepair)
+
+	vnet_mkjail carp_basic_v4_one ${bridge} ${epair_one}a ${epair_two}a
+	vnet_mkjail carp_basic_v4_two ${epair_one}b
+	vnet_mkjail carp_basic_v4_three ${epair_two}b
+
+	jexec carp_basic_v4_one ifconfig ${bridge} 192.0.2.4/29 up
+	jexec carp_basic_v4_one ifconfig ${bridge} addm ${epair_one}a \
+	    addm ${epair_two}a
+	jexec carp_basic_v4_one ifconfig ${epair_one}a up
+	jexec carp_basic_v4_one ifconfig ${epair_two}a up
+
+	jexec carp_basic_v4_two ifconfig ${epair_one}b 192.0.2.202/29 up
+	jexec carp_basic_v4_two ifconfig ${epair_one}b add vhid 1 192.0.2.1/29
+
+	jexec carp_basic_v4_three ifconfig ${epair_two}b 192.0.2.203/29 up
+	jexec carp_basic_v4_three ifconfig ${epair_two}b add vhid 1 \
+	    192.0.2.1/29
+
+	wait_for_carp carp_basic_v4_two ${epair_one}b \
+	    carp_basic_v4_three ${epair_two}b
+
+	atf_check -s exit:0 -o ignore jexec carp_basic_v4_one \
+	    ping -c 3 192.0.2.1
+}
+
+basic_v4_cleanup()
+{
+	vnet_cleanup
+}
+
+atf_test_case "basic_v6" "cleanup"
+basic_v6_head()
+{
+	atf_set descr 'Basic CARP test (IPv6)'
+	atf_set require.user root
+}
+
+basic_v6_body()
+{
+	if ! kldstat -q -m carp; then
+		atf_skip "This test requires carp"
+	fi
+
+	vnet_init
+	bridge=$(vnet_mkbridge)
+	epair_one=$(vnet_mkepair)
+	epair_two=$(vnet_mkepair)
+
+	vnet_mkjail carp_basic_v6_one ${bridge} ${epair_one}a ${epair_two}a
+	vnet_mkjail carp_basic_v6_two ${epair_one}b
+	vnet_mkjail carp_basic_v6_three ${epair_two}b
+
+	jexec carp_basic_v6_one ifconfig ${bridge} inet6 2001:db8::0:4/64 up \
+	    no_dad
+	jexec carp_basic_v6_one ifconfig ${bridge} addm ${epair_one}a \
+	    addm ${epair_two}a
+	jexec carp_basic_v6_one ifconfig ${epair_one}a up
+	jexec carp_basic_v6_one ifconfig ${epair_two}a up
+
+	jexec carp_basic_v6_two ifconfig ${epair_one}b inet6 \
+	    2001:db8::1:2/64 up no_dad
+	jexec carp_basic_v6_two ifconfig ${epair_one}b inet6 add vhid 1 \
+	    2001:db8::0:1/64
+
+	jexec carp_basic_v6_three ifconfig ${epair_two}b inet6 2001:db8::1:3/64 up no_dad
+	jexec carp_basic_v6_three ifconfig ${epair_two}b inet6 add vhid 1 \
+	    2001:db8::0:1/64
+
+	wait_for_carp carp_basic_v6_two ${epair_one}b \
+	    carp_basic_v6_three ${epair_two}b
+
+	atf_check -s exit:0 -o ignore jexec carp_basic_v6_one \
+	    ping6 -c 3 2001:db8::0:1
+}
+
+basic_v6_cleanup()
+{
+	vnet_cleanup
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case "basic_v4"
+	atf_add_test_case "basic_v6"
+}