On 10/20/22 18:33, Ilya Maximets wrote:
On 10/20/22 17:32, Aaron Conole wrote:
Hi Ilya,
Ilya Maximets i.maximets@ovn.org writes:
On 10/19/22 20:30, Aaron Conole wrote:
Previous commit resolves a WARN splat that can be difficult to reproduce, but with the ovs-dpctl.py utility, it can be trivial. Introduce a test case which creates a DP, and then downgrades the feature set. This will include a utility 'ovs-dpctl.py' that can be extended to do additional work.
Signed-off-by: Aaron Conole aconole@redhat.com Signed-off-by: Kevin Sprague ksprague0711@gmail.com
MAINTAINERS | 1 + tools/testing/selftests/Makefile | 1 + .../selftests/net/openvswitch/Makefile | 13 + .../selftests/net/openvswitch/openvswitch.sh | 216 +++++++++ .../selftests/net/openvswitch/ovs-dpctl.py | 411 ++++++++++++++++++ 5 files changed, 642 insertions(+) create mode 100644 tools/testing/selftests/net/openvswitch/Makefile create mode 100755 tools/testing/selftests/net/openvswitch/openvswitch.sh create mode 100644 tools/testing/selftests/net/openvswitch/ovs-dpctl.py
diff --git a/MAINTAINERS b/MAINTAINERS index abbe88e1c50b..295a6b0fbe26 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15434,6 +15434,7 @@ S: Maintained W: http://openvswitch.org F: include/uapi/linux/openvswitch.h F: net/openvswitch/ +F: tools/testing/selftests/net/openvswitch/ OPERATING PERFORMANCE POINTS (OPP) M: Viresh Kumar vireshk@kernel.org
...
+exit ${exitcode} diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py new file mode 100644 index 000000000000..791d76b7adcd --- /dev/null +++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py @@ -0,0 +1,411 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0
+# Controls the openvswitch module. Part of the kselftest suite, but +# can be used for some diagnostic purpose as well.
+import logging +import multiprocessing +import socket +import struct +import sys
+try:
- from libnl.attr import NLA_NESTED, NLA_STRING, NLA_U32, NLA_UNSPEC
- from libnl.attr import nla_get_string, nla_get_u32
- from libnl.attr import nla_put, nla_put_string, nla_put_u32
- from libnl.attr import nla_policy
- from libnl.error import errmsg
- from libnl.genl.ctrl import genl_ctrl_resolve
- from libnl.genl.genl import genl_connect, genlmsg_parse, genlmsg_put
- from libnl.handlers import nl_cb_alloc, nl_cb_set
- from libnl.handlers import NL_CB_CUSTOM, NL_CB_MSG_IN, NL_CB_VALID
- from libnl.handlers import NL_OK, NL_STOP
- from libnl.linux_private.netlink import NLM_F_ACK, NLM_F_DUMP
- from libnl.linux_private.netlink import NLM_F_REQUEST, NLMSG_DONE
- from libnl.msg import NL_AUTO_SEQ, nlmsg_alloc, nlmsg_hdr
- from libnl.nl import NLMSG_ERROR, nl_recvmsgs_default, nl_send_auto
- from libnl.socket_ import nl_socket_alloc, nl_socket_set_cb
- from libnl.socket_ import nl_socket_get_local_port
+except ModuleNotFoundError:
- print("Need to install the python libnl3 library.")
Hey, Aaron and Kevin. Selftests sounds like a very important and long overdue thing to add. Thanks for working on this!
I have some worries about the libnl3 library though. It doesn't seem to be maintained well. It it maintained by a single person, it it was at least 3 different single persons over the last 7 years via forks. It didn't get any significant development done since 2015 as well and no commits at all for a last 1.5 years. It is not packaged by any major distributions.
:-/ On my fedora:
11:12:24 aconole@RHTPC1VM0NT ~$ dnf search python3-libnl3 Last metadata expiration check: 1 day, 0:25:11 ago on Wed 19 Oct 2022 10:47:21 AM EDT. ===================== Name Exactly Matched: python3-libnl3 ===================== python3-libnl3.x86_64 : libnl3 binding for Python 3
And I can use it:
11:18:39 aconole@RHTPC1VM0NT {(6a5c83bdd991...)} ~/git/linux/tools/testing/selftests/net/openvswitch$ sudo python3 ./ovs-dpctl.py show foop Lookups: Hit: 0 Missed: 0 Lost: 0 Flows: 0 Masks: Hit: 0 Total: 0 Cache: Hit: 0 Caches: Masks-cache: size: 256 Port 0: foop (internal) 11:18:43 aconole@RHTPC1VM0NT {(6a5c83bdd991...)} ~/git/linux/tools/testing/selftests/net/openvswitch$ rpm -qa | grep python3-libnl3 python3-libnl3-3.5.0-6.fc34.x86_64 11:19:01 aconole@RHTPC1VM0NT {(6a5c83bdd991...)} ~/git/linux/tools/testing/selftests/net/openvswitch$
Was there some place you did not find it?
You're right, I missed that somehow. But this is not an https://github.com/coolshou/libnl3 project. :) These are python bindings for the C libnl library:
$ dnf info python3-libnl3 Available Packages Name : python3-libnl3 Version : 3.7.0 Release : 1.fc36 Architecture : x86_64 Size : 153 k Source : libnl3-3.7.0-1.fc36.src.rpm Repository : updates Summary : libnl3 binding for Python 3 URL : http://www.infradead.org/~tgr/libnl/ License : LGPLv2 Description : Python 3 bindings for libnl3
Actually, I can't find an equivalent package for Ubuntu 22.04. And since pip is not an option (pip install libnl3 is a different package), there is no way to install it there beside building from sources.
Am I still missing something?
I'm talking about https://github.com/coolshou/libnl3 . Please, correct me if that is not the right one. There are too many libraies with the name libnl out there... That is also not a great sign.
Yes, this is the project.
Doensn't look like it...
We did look at some of the ones you mentioned, but didn't find much.
It is a sparse landscape of projects that provide netlink support in python.
The C library libnl (https://github.com/thom311/libnl) seems to be well maintained in general. It has experimental python bindings which are not really supported much. Python bindings received only 2 actual code-changing commits in the last 7 years. Both of them are just python 2/3 compatibility changes. Maybe that is not that big of a deal since it's not really a real python library, but a wrapper on top of a main C library. However, I didn't find these python bindings to be packaged in distributions. And they seem to be not available in pip as well. So, building them is kind of a pain.
Well, the python libnl3 should be installable via pip3. Ex:
11:27:15 aconole@RHTPC1VM0NT ~$ pip3 install libnl3 Defaulting to user installation because normal site-packages is not writeable Collecting libnl3 Using cached libnl3-0.3.0-py3-none-any.whl (89 kB) Installing collected packages: libnl3 Successfully installed libnl3-0.3.0
And this is https://pypi.org/project/libnl3/, which is the https://github.com/coolshou/libnl3 project. So, by installing libnl3 via pip and installing python3-libnl3 from the fedora you're getting two completely different libraries.
So, which one users should use?
I can't find python bindings for the C libnl (which is the python3-libnl3 package) in pypi, so it can't be installed with pip.
So I guess that is worth something.
At least on Fedora it is installable from distribution as well.
There is another option which is pyroute2. It positions itself primarily as a netlink library and it does include an pyroute2.netlink module indeed: https://github.com/svinota/pyroute2/tree/master/pyroute2/netlink See the __init__.py for usage examples.
This one looks to me like the most trustworthy. It is actively used by everyone in the python networking world, e.g. by OpenStack. And it is actively developed and maintained unlike other netlink-related python projects. It is also packaged in most of the main distributions, so it's easy to install and use. Many people already have it installed for other purposes.
TBH, I didn't compare the functionality, but I'd expect that most of the things we need are implemented.
What do you think?
We can certainly look at switching, but having a quick glance, it seems pyroute2 expects to provide the genl commands as well, so they would want us to create an ovs module in pyroute2 that includes all of the ovs family support. Of course, we can always do this just in our module, but I think it isn't the way pyroute2 project wants to be structured. More like a library that provides all the command functionality.
What I was thinking is to import pyroute2.netlink and the pyroute2.netlink.generic and go from there. But I didn't look too deep on how to actually implement the functionality.
The python bindings for the C libnl (python3-libnl3) sounds like a fine option since they are actually packaged in distributions (missed that in my initial reply). However, the fact that you can not install them via pip and actually you will install something but completely different is kind of weird. This has to be at least better documented, so users will know what to install and they will not try to use pip for that.
On the other note, I'm not a real python developer, but the code looks more like a C than a python even for me. Firstly, I'd say that it would be great to maintain some coding style, e.g. by checking with flake8 and/or black. See some issues/suggestions provided by these tools below.
Agreed. BTW, on the rhel8 system I developed on:
[root@wsfd-netdev60 openvswitch]# flake8 ./ovs-dpctl.py [root@wsfd-netdev60 openvswitch]#
So, I guess it is probably that I should have used a different system to do the flake8 checks.
Maybe the python version is different... I was running on f36 with python 3.10. Also, the list of defaults might be different. flake8 doesn't use default ignore list if one is explicitly provided.
Secondly, we shouldd at least use argparse for argument parsing. It's part of the standard library since python 3.2, so doens't require any special dependencies to be installed.
Okay - I can switch to argparse. TBH, I haven't kept up with python standard library for some time.
Well, 3.2 was released 11 years ago. :)
Some parts of the code can probably be re-written to be more "pythonic" as well, but I won't dive into that for now. I didn't review the code deep enough for that.
I have difficulty sometimes understanding what it means to be "Real Python (tm)" - I don't plan to change things too much. I can certainly switch to using argparse, but unless you give something you want to change, I would not change anything.
I breifly looked through code and though I don't fully understand what this piece supposed to do:
segment = hdrval.find(":")if segment == -1:segment = len(hdrval)hdrver = int(hdrval[:segment], 0)if len(hdrval[:segment]):userfeatures = int(hdrval[:segment], 0)but I have a strong feeling that this part can benefit from use of hdrval.split(':').
I won't insist on that too much. :)
Best regards, Ilya Maximets.