On 6/3/21 2:38 PM, Aaron Conole wrote: > Eelco Chaudron <echau...@redhat.com> writes: > >> On 2 Jun 2021, at 18:21, Aaron Conole wrote: >> >>> Eelco Chaudron <echau...@redhat.com> writes: >>> >>>> Currently, conntrack in the kernel has an undocumented feature referred >>>> to as all-zero IP address SNAT. Basically, when a source port >>>> collision is detected during the commit, the source port will be >>>> translated to an ephemeral port. If there is no collision, no SNAT is >>>> performed. >>>> >>>> This patchset documents this behavior and adds a self-test to verify >>>> it's not changing. In addition, a datapath feature flag is added for >>>> the all-zero IP SNAT case. This will help applications on top of OVS, >>>> like OVN, to determine this feature can be used. >>>> >>>> Signed-off-by: Eelco Chaudron <echau...@redhat.com> >>>> --- >>>> v4: Added datapath support flag for all-zero SNAT. >>>> v3: Renamed NULL SNAT to all-zero IP SNAT. >>>> v2: Fixed NULL SNAT to only work in the -rpl state to be inline with >>>> OpenShift-SDN's behavior. >>>> >>>> lib/ct-dpif.c | 8 +++++++ >>>> lib/ct-dpif.h | 6 +++++ >>>> lib/dpif-netdev.c | 1 + >>>> lib/dpif-netlink.c | 11 +++++++++ >>>> lib/dpif-provider.h | 5 ++++ >>>> lib/ovs-actions.xml | 10 ++++++++ >>>> ofproto/ofproto-dpif.c | 22 +++++++++++++++++- >>>> ofproto/ofproto-dpif.h | 5 +++- >>>> tests/system-kmod-macros.at | 7 ++++++ >>>> tests/system-traffic.at | 46 >>>> ++++++++++++++++++++++++++++++++++++++ >>>> tests/system-userspace-macros.at | 10 ++++++++ >>>> vswitchd/vswitch.xml | 9 +++++++ >>>> 12 files changed, 138 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/lib/ct-dpif.c b/lib/ct-dpif.c >>>> index 6a5ba052d..cfc2315e3 100644 >>>> --- a/lib/ct-dpif.c >>>> +++ b/lib/ct-dpif.c >>>> @@ -889,3 +889,11 @@ ct_dpif_get_timeout_policy_name(struct dpif *dpif, >>>> uint32_t tp_id, >>>> dpif, tp_id, dl_type, nw_proto, tp_name, is_generic) >>>> : EOPNOTSUPP); >>>> } >>>> + >>>> +int >>>> +ct_dpif_get_features(struct dpif *dpif, enum ct_features *features) >>>> +{ >>> >>> NIT-mode: >>> >>> Are these features or capabilities? I ask because we may want to add >>> support for things like tcp loose mode, etc, and not sure if there would >>> need to be a corresponding set function (to enable / disable), and how >>> that should look. I'm okay with keeping it as-is for here and adding >>> the corresponding set function later, but it would seem strange to try >>> and "set" support for all-zero snat, etc. >> >> Guess the line between feature and capabilities is rather thin... The >> code for checking the datapath support, check_support(), is calling >> all of this features, rather than capabilities. >> >> I guess ct_zero_snat is a none configurable feature ;) But more >> seriously, I could go ahead and change the naming from feature to >> capability. As most of the configurable "features" have their own >> callback. > > I guess it doesn't matter too much, but I worry about whether we start > trying to enable. Maybe we just make it unsupportable? I'm just > concerned that when we add things like tcp_loose or try to make > tcp_liberal as a configurable in the kernel DP, there could be some > confusion. Maybe it isn't too important. Okay, we can cross those > bridges when we get there. > >>>> + return (dpif->dpif_class->ct_get_features >>>> + ? dpif->dpif_class->ct_get_features(dpif, features) >>>> + : EOPNOTSUPP); >>>> +} >> >> <SNIP> >> >>>> diff --git a/tests/system-userspace-macros.at >>>> b/tests/system-userspace-macros.at >>>> index 34f82cee3..9f0d38dfb 100644 >>>> --- a/tests/system-userspace-macros.at >>>> +++ b/tests/system-userspace-macros.at >>>> @@ -96,6 +96,16 @@ m4_define([CHECK_CONNTRACK_FRAG_OVERLAP]) >>>> # >>>> m4_define([CHECK_CONNTRACK_NAT]) >>>> >>>> +# CHECK_CONNTRACK_ZEROIP_SNAT() >>>> +# >>>> +# Perform requirements checks for running conntrack all-zero IP SNAT >>>> tests. >>>> +# The userspace datapath does not support all-zero IP SNAT. >>>> +# >>>> +m4_define([CHECK_CONNTRACK_ZEROIP_SNAT], >>>> +[ >>>> + AT_SKIP_IF([:]) >>>> +]) >>> >>> I didn't check too close, but maybe it's possible to make this check the >>> capabilities bits and then it could be extended to everywhere. >> >> I was thinking about using "ovs-appctl dpif/show-dp-features" after I >> added the features check. However none of the other test cases do >> this, so I thought there might be a reason? It might be that I need to >> configure/setup OVS to run the test command, and not sure if there is >> a nice clean way to shut down if the feature is not supported. > > Okay. Maybe it's not possible in the test framework.
Hmm. AFAICT, daemons will be stopped by on_exit hooks, so it should not be a problem. Just call the check after starting the daemon. BTW, have you checked the windows datapath? I don't see the "ifdef _WIN32" in this patch, so we're reporting the feature as supported on windows. > >>>> + >>>> # CHECK_CONNTRACK_TIMEOUT() >>>> # >>>> # Perform requirements checks for running conntrack customized timeout >>>> tests. >>>> diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml >>>> index 4597a215d..d8ea287d5 100644 >>>> --- a/vswitchd/vswitch.xml >>>> +++ b/vswitchd/vswitch.xml >>>> @@ -6126,6 +6126,15 @@ ovs-vsctl add-port br0 p0 -- set Interface p0 >>>> type=patch options:peer=p1 \ >>>> True if the datapath supports OVS_ACTION_ATTR_DROP. If false, >>>> explicit drop action will not be sent to the datapath. >>>> </column> >>>> + <column name="capabilities" key="ct_zero_snat" >>>> + type='{"type": "boolean"}'> >>>> + True if the datapath supports all-zero SNAT. This is a special >>>> case >>>> + if the <code>src</code> IP address is configured as all 0's, i.e., >>>> + <code>nat(src=0.0.0.0)</code>. In this case, when a source port >>>> + collision is detected during the commit, the source port will be >>>> + translated to an ephemeral port. If there is no collision, no SNAT >>>> + is performed. >>>> + </column> >>>> </group> >>>> >>>> <group title="Common Columns"> > > > Acked-by: Aaron Conole <acon...@redhat.com> > > _______________________________________________ > dev mailing list > d...@openvswitch.org > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev