selftests: openvswitch: add ct-nat test case with ipv4

Building on the previous work, add a very simplistic NAT case
using ipv4.  This just tests dnat transformation
Signed-off-by: Aaron Conole <aconole@redhat.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/net/openvswitch/openvswitch.sh

@@ -14,6 +14,7 @@ tests="
 	arp_ping				eth-arp: Basic arp ping between two NS
 	ct_connect_v4				ip4-ct-xon: Basic ipv4 tcp connection using ct
 	connect_v4				ip4-xon: Basic ipv4 ping between two NS
+	nat_connect_v4				ip4-nat-xon: Basic ipv4 tcp connection via NAT
 	netlink_checks				ovsnl: validate netlink attrs and settings
 	upcall_interfaces			ovs: test the upcall interfaces"
 
@@ -300,6 +301,69 @@ test_connect_v4 () {
 	return 0
 }
 
+# nat_connect_v4 test
+#  - client has 1500 byte MTU
+#  - server has 1500 byte MTU
+#  - use ICMP to ping in each direction
+#  - only allow CT state stuff to pass through new in c -> s
+test_nat_connect_v4 () {
+	which nc >/dev/null 2>/dev/null || return $ksft_skip
+
+	sbx_add "test_nat_connect_v4" || return $?
+
+	ovs_add_dp "test_nat_connect_v4" nat4 || return 1
+	info "create namespaces"
+	for ns in client server; do
+		ovs_add_netns_and_veths "test_nat_connect_v4" "nat4" "$ns" \
+		    "${ns:0:1}0" "${ns:0:1}1" || return 1
+	done
+
+	ip netns exec client ip addr add 172.31.110.10/24 dev c1
+	ip netns exec client ip link set c1 up
+	ip netns exec server ip addr add 172.31.110.20/24 dev s1
+	ip netns exec server ip link set s1 up
+
+	ip netns exec client ip route add default via 172.31.110.20
+
+	ovs_add_flow "test_nat_connect_v4" nat4 \
+		'in_port(1),eth(),eth_type(0x0806),arp()' '2' || return 1
+	ovs_add_flow "test_nat_connect_v4" nat4 \
+		'in_port(2),eth(),eth_type(0x0806),arp()' '1' || return 1
+	ovs_add_flow "test_nat_connect_v4" nat4 \
+		"ct_state(-trk),in_port(1),eth(),eth_type(0x0800),ipv4(dst=192.168.0.20)" \
+		"ct(commit,nat(dst=172.31.110.20)),recirc(0x1)"
+	ovs_add_flow "test_nat_connect_v4" nat4 \
+		"ct_state(-trk),in_port(2),eth(),eth_type(0x0800),ipv4()" \
+		"ct(commit,nat),recirc(0x2)"
+
+	ovs_add_flow "test_nat_connect_v4" nat4 \
+		"recirc_id(0x1),ct_state(+trk-inv),in_port(1),eth(),eth_type(0x0800),ipv4()" "2"
+	ovs_add_flow "test_nat_connect_v4" nat4 \
+		"recirc_id(0x2),ct_state(+trk-inv),in_port(2),eth(),eth_type(0x0800),ipv4()" "1"
+
+	# do a ping
+	ovs_sbx "test_nat_connect_v4" ip netns exec client ping 192.168.0.20 -c 3 || return 1
+
+	# create an echo server in 'server'
+	echo "server" | \
+		ovs_netns_spawn_daemon "test_nat_connect_v4" "server" \
+				nc -lvnp 4443
+	ovs_sbx "test_nat_connect_v4" ip netns exec client nc -i 1 -zv 192.168.0.20 4443 || return 1
+
+	# Now test in the other direction (should fail)
+	echo "client" | \
+		ovs_netns_spawn_daemon "test_nat_connect_v4" "client" \
+				nc -lvnp 4443
+	ovs_sbx "test_nat_connect_v4" ip netns exec client nc -i 1 -zv 172.31.110.10 4443
+	if [ $? == 0 ]; then
+	   info "connect to client was successful"
+	   return 1
+	fi
+
+	info "done..."
+	return 0
+}
+
 # netlink_validation
 # - Create a dp
 # - check no warning with "old version" simulation

tools/testing/selftests/net/openvswitch/ovs-dpctl.py

@@ -530,6 +530,68 @@ class ovsactions(nla):
                         else:
                             ctact["attrs"].append([scan[1], None])
                         actstr = actstr[strspn(actstr, ", ") :]
+                    # it seems strange to put this here, but nat() is a complex
+                    # sub-action and this lets it sit anywhere in the ct() action
+                    if actstr.startswith("nat"):
+                        actstr = actstr[3:]
+                        natact = ovsactions.ctact.natattr()
+
+                        if actstr.startswith("("):
+                            t = None
+                            actstr = actstr[1:]
+                            if actstr.startswith("src"):
+                                t = "OVS_NAT_ATTR_SRC"
+                                actstr = actstr[3:]
+                            elif actstr.startswith("dst"):
+                                t = "OVS_NAT_ATTR_DST"
+                                actstr = actstr[3:]
+
+                            actstr, ip_block_min = parse_extract_field(
+                                actstr, "=", "([0-9a-fA-F\.]+)", str, False
+                            )
+                            actstr, ip_block_max = parse_extract_field(
+                                actstr, "-", "([0-9a-fA-F\.]+)", str, False
+                            )
+
+                            actstr, proto_min = parse_extract_field(
+                                actstr, ":", "(\d+)", int, False
+                            )
+                            actstr, proto_max = parse_extract_field(
+                                actstr, "-", "(\d+)", int, False
+                            )
+
+                            if t is not None:
+                                natact["attrs"].append([t, None])
+
+                                if ip_block_min is not None:
+                                    natact["attrs"].append(
+                                        ["OVS_NAT_ATTR_IP_MIN", ip_block_min]
+                                    )
+                                if ip_block_max is not None:
+                                    natact["attrs"].append(
+                                        ["OVS_NAT_ATTR_IP_MAX", ip_block_max]
+                                    )
+                                if proto_min is not None:
+                                    natact["attrs"].append(
+                                        ["OVS_NAT_ATTR_PROTO_MIN", proto_min]
+                                    )
+                                if proto_max is not None:
+                                    natact["attrs"].append(
+                                        ["OVS_NAT_ATTR_PROTO_MAX", proto_max]
+                                    )
+
+                            for natscan in (
+                                ("persistent", "OVS_NAT_ATTR_PERSISTENT"),
+                                ("hash", "OVS_NAT_ATTR_PROTO_HASH"),
+                                ("random", "OVS_NAT_ATTR_PROTO_RANDOM"),
+                            ):
+                                if actstr.startswith(natscan[0]):
+                                    actstr = actstr[len(natscan[0]) :]
+                                    natact["attrs"].append([natscan[1], None])
+                                    actstr = actstr[strspn(actstr, ", ") :]
+
+                        ctact["attrs"].append(["OVS_CT_ATTR_NAT", natact])
+                        actstr = actstr[strspn(actstr, ",) ") :]
 
                 self["attrs"].append(["OVS_ACTION_ATTR_CT", ctact])
                 parsed = True