Subject: Re: [ovs-dev] [PATCH net-next 3/4] selftests: openvswitch: add basic ct test case parsing

From: Aaron Conole <[email-masked]>
Date: Mon, 10 Jul 2023 12:21:42 -0400

Adrian Moreno <[email-masked]> writes:

> On 6/28/23 18:27, Aaron Conole wrote:
>> Forwarding via ct() action is an important use case for openvswitch, but
>> generally would require using a full ovs-vswitchd to get working. Add a
>> ct action parser for basic ct test case.
>> Signed-off-by: Aaron Conole <[email-masked]>
>> ---
>> NOTE: 3 lines flag the line-length checkpatch warning, but there didnt
>>        seem to be a really good way of breaking the lines smaller.
>>   .../selftests/net/openvswitch/openvswitch.sh  | 68
>> +++++++++++++++++++
>>   .../selftests/net/openvswitch/ovs-dpctl.py    | 39 +++++++++++
>>   2 files changed, 107 insertions(+)
>> diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> b/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> index 5d60a9466dab3..40a66c72af0f0 100755
>> --- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> +++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> @@ -12,6 +12,7 @@ TRACING=0
>>     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
>>   	netlink_checks				ovsnl: validate netlink attrs and settings
>>   	upcall_interfaces			ovs: test the upcall interfaces"
>> @@ -193,6 +194,73 @@ test_arp_ping () {
>>   	return 0
>>   }
>>   +# ct_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_ct_connect_v4 () {
>> +
>> +	which nc >/dev/null 2>/dev/null || return $ksft_skip
>> +
>> +	sbx_add "test_ct_connect_v4" || return $?
>> +
>> +	ovs_add_dp "test_ct_connect_v4" ct4 || return 1
>> +	info "create namespaces"
>> +	for ns in client server; do
>> +		ovs_add_netns_and_veths "test_ct_connect_v4" "ct4" "$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
>> +
>> +	# Add forwarding for ARP and ip packets - completely wildcarded
>> +	ovs_add_flow "test_ct_connect_v4" ct4 \
>> +		'in_port(1),eth(),eth_type(0x0806),arp()' '2' || return 1
>> +	ovs_add_flow "test_ct_connect_v4" ct4 \
>> +		'in_port(2),eth(),eth_type(0x0806),arp()' '1' || return 1
>> +	ovs_add_flow "test_ct_connect_v4" ct4 \
>> +		     'ct_state(-trk),eth(),eth_type(0x0800),ipv4()' \
>> +		     'ct(commit),recirc(0x1)' || return 1
>> +	ovs_add_flow "test_ct_connect_v4" ct4 \
>> +		     'recirc_id(0x1),ct_state(+trk+new),in_port(1),eth(),eth_type(0x0800),ipv4(src=172.31.110.10)' \
>> +		     '2' || return 1
>> +	ovs_add_flow "test_ct_connect_v4" ct4 \
>> +		     'recirc_id(0x1),ct_state(+trk+est),in_port(1),eth(),eth_type(0x0800),ipv4(src=172.31.110.10)' \
>> +		     '2' || return 1
>> +	ovs_add_flow "test_ct_connect_v4" ct4 \
>> +		     'recirc_id(0x1),ct_state(+trk+est),in_port(2),eth(),eth_type(0x0800),ipv4(dst=172.31.110.10)' \
>> +		     '1' || return 1
>> +	ovs_add_flow "test_ct_connect_v4" ct4 \
>> +		     'recirc_id(0x1),ct_state(+trk+inv),eth(),eth_type(0x0800),ipv4()' 'drop' || \
>> +		     return 1
>> +
>> +	# do a ping
>> +	ovs_sbx "test_ct_connect_v4" ip netns exec client ping 172.31.110.20 -c 3 || return 1
>> +
>> +	# create an echo server in 'server'
>> +	echo "server" | \
>> +		ovs_netns_spawn_daemon "test_ct_connect_v4" "server" \
>> +				nc -lvnp 4443
>> +	ovs_sbx "test_ct_connect_v4" ip netns exec client nc -i 1 -zv 172.31.110.20 4443 || return 1
>> +
>> +	# Now test in the other direction (should fail)
>> +	echo "client" | \
>> +		ovs_netns_spawn_daemon "test_ct_connect_v4" "client" \
>> +				nc -lvnp 4443
>> +	ovs_sbx "test_ct_connect_v4" ip netns exec client nc -i 1 -zv 172.31.110.10 4443
>> +	if [ $? == 0 ]; then
>> +	   info "ct connect to client was successful"
>> +	   return 1
>> +	fi
>> +
>> +	info "done..."
>> +	return 0
>> +}
>> +
>>   # connect_v4 test
>>   #  - client has 1500 byte MTU
>>   #  - server has 1500 byte MTU
>> diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
>> index 799bfb3064b90..704cb4adf79a9 100644
>> --- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
>> +++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
>> @@ -62,6 +62,15 @@ def macstr(mac):
>>       return outstr
>>     +def strcspn(str1, str2):
>> +    tot = 0
>> +    for char in str1:
>> +        if str2.find(char) != -1:
>> +            return tot
>> +        tot += 1
>> +    return tot
>> +
>> +
>>   def strspn(str1, str2):
>>       tot = 0
>>       for char in str1:
>> @@ -477,6 +486,36 @@ class ovsactions(nla):
>>                       actstr = actstr[strspn(actstr, ", ") :]
>>                       parsed = True
>>   +            if parse_starts_block(actstr, "ct(", False):
>> +                actstr = actstr[len("ct(") :]
>> +                ctact = ovsactions.ctact()
>> +
>> +                for scan in (
>> +                    ("commit", "OVS_CT_ATTR_COMMIT", None),
>> +                    ("force_commit", "OVS_CT_ATTR_FORCE_COMMIT", None),
>> +                    ("zone", "OVS_CT_ATTR_ZONE", int),
>> +                    ("mark", "OVS_CT_ATTR_MARK", int),
>> +                    ("helper", "OVS_CT_ATTR_HELPER", lambda x, y: str(x)),
>> +                    ("timeout", "OVS_CT_ATTR_TIMEOUT", lambda x, y: str(x)),
>> +                ):
>> +                    if actstr.startswith(scan[0]):
>> +                        actstr = actstr[len(scan[0]) :]
>> +                        if scan[2] is not None:
>> +                            if actstr[0] != "=":
>> +                                raise ValueError("Invalid ct attr")
>> +                            actstr = actstr[1:]
>> +                            pos = strcspn(actstr, ",)")
>> +                            datum = scan[2](actstr[:pos], 0)
>
> It seems the scan function is only called with "0" as second
> argument. Wouldn't it be easier to omit that extra argument (which is
> the default value for "int" anyway) and simplify the lambda for
> "helper" and "timeout"?
>
> Alternatively, we could have a function that tries both base-16 and base-10.

I think '10' is the default argument for int() -

   >>> print("%d" % int("0x12"))
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   ValueError: invalid literal for int() with base 10: '0x12'
   >>> print("%d" % int("0x12", 0))
   18

So, I will keep it as-is.

>> +                            ctact["attrs"].append([scan[1], datum])
>> +                            actstr = actstr[len(datum) :]
>
> "datum" can be of type int and ints don't have len(). Maybe just use "pos" directly?

Good catch!  I'll correct it.

>> +                        else:
>> +                            ctact["attrs"].append([scan[1], None])
>> +                        actstr = actstr[strspn(actstr, ", ") :]
>> +
>> +                self["attrs"].append(["OVS_ACTION_ATTR_CT", ctact])
>> +                actstr = actstr[strspn(actstr, "), ") :]
>> +                parsed = True
>> +
>>               if not parsed:
>>                   raise ValueError("Action str: '%s' not supported" % actstr)
>>