Re: [ovs-dev] [PATCH net-next 4/4] selftests: openvswitch: add ct-nat test case with ipv4

[Aaron Conole <aconole@redhat.com>]

Adrian Moreno <amorenoz@redhat.com> writes:

> On 6/28/23 18:27, Aaron Conole wrote:
>> 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>
>
> Hi Aaron,
>
> I know that the goal is not to support the full syntax, and that nat
> is a specially convoluted action, so I'm just commenting on the
> low-hanging fruits (see below).

Thanks, Adrian!

>> ---
>>   .../selftests/net/openvswitch/openvswitch.sh  | 64 +++++++++++++++++++
>>   .../selftests/net/openvswitch/ovs-dpctl.py    | 60 +++++++++++++++++
>>   2 files changed, 124 insertions(+)
>> diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> b/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> index 40a66c72af0f0..dced4f612a78c 100755
>> --- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> +++ b/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
>> diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
>> index 704cb4adf79a9..12ba5265b88fb 100644
>> --- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
>> +++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
>> @@ -511,6 +511,66 @@ 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
>> +                            )
>
> Having the ":" character here makes this line parse the port as well
> (i.e: 1.1.1.1:6789 as ip_block_max) which then makes ip address
> parsing fail.

Ugh... good catch.  I'll re-work this section a bit.  I was trying to
keep it simple to catch both ipv4 and ipv6 syntax.

>> +                            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 (
>> +                                ("persist", "OVS_NAT_ATTR_PERSISTENT"),
>> +                                ("hash", "OVS_NAT_ATTR_PROTO_HASH"),
>> +                                ("random", "OVS_NAT_ATTR_PROTO_RANDOM"),
>> +                            ):
>
> I think this is not taking into account the comma that separates
> ip:port from these keywords. A possible solution would be to add it to
> the natscan (e.g: s/persist/,persist/).

I'll double check it, thanks!

>> +                                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])
>>                   actstr = actstr[strspn(actstr, "), ") :]