[ovs-dev] [PATCH v2 09/13] ovn-trace: Add some basic tracing for ct_snat and ct_dnat actions.

Andy Zhou azhou at ovn.org
Thu May 4 04:04:45 UTC 2017


On Wed, May 3, 2017 at 6:43 PM, Mickey Spiegel <mickeys.dev at gmail.com> wrote:
> On Wed, May 3, 2017 at 8:45 AM, Ben Pfaff <blp at ovn.org> wrote:
>
>> Without this support, ovn-trace is not very useful with OpenStack, which
>> uses connection tracking extensively.
>>
>> Signed-off-by: Ben Pfaff <blp at ovn.org>
>>
>
> Acked-by: Mickey Spiegel <mickeys.dev at gmail.com>
>
> A couple of minor comments below.
>
> ---
>>  ovn/utilities/ovn-trace.8.xml | 50 ++++++++++++++++++++++++++++++
>> +++++++++++
>>  ovn/utilities/ovn-trace.c     | 52 ++++++++++++++++++++++++++++++
>> ++++++++++---
>>  2 files changed, 99 insertions(+), 3 deletions(-)
>>
>> diff --git a/ovn/utilities/ovn-trace.8.xml b/ovn/utilities/ovn-trace.8.xml
>> index 8bb329bfbd71..b2d46ac3d50b 100644
>> --- a/ovn/utilities/ovn-trace.8.xml
>> +++ b/ovn/utilities/ovn-trace.8.xml
>> @@ -166,6 +166,56 @@
>>      output;
>>    </pre>
>>
>> +  <h2>Stateful Actions</h2>
>>
>
> The flow is a little funny. At the beginning of the output section:
>
>     <code>ovn-trace</code> supports the three different forms of output,
> each
>     described in a separate section below.
>
> Now there is another h2 section in between the three sections describing
> the different forms of output.
>
> Perhaps just use <h3>?

May be in its own section?
>
> +
>> +  <p>
>> +    Some OVN logical actions use or update state that is not available in
>> the
>> +    southbound database.  <code>ovn-trace</code> handles these actions as
>> +    described below:
>> +  </p>
>> +
>> +  <dl>
>> +    <dt>ct_next</dt>
>> +    <dd>
>> +      By default <code>ovn-trace</code> treats flows as ``tracked'' and
>> +      ``established.''  The <code>--ct</code> option overrides this
>> behavior;
>> +      refer to its description for more information.
>> +    </dd>
>> +
>> +    <dt>ct_commit</dt>
>> +    <dd>
>> +      This action is treated as a no-op.
>> +    </dd>
>> +
>> +    <dt>ct_dnat</dt>
>> +    <dt>ct_snat</dt>
>> +    <dd>
>> +      <p>
>> +        When one of these action is used without arguments, to ``un-NAT''
>> a
>>
>
> s/action/actions
>
>
>> +        packet, <code>ovn-trace</code> assumes that no NAT state was
>> available
>> +        and treats it as a no-op.
>> +      </p>
>> +
>> +      <p>
>> +        With an argument, <code>ovn-trace</code> sets the IP destination
>> or
>> +        source, as appropriate, to the given address. It also sets
>> +        <code>ct.dnat</code> or <code>ct.snat</code> to 1 to indicate
>> that NAT
>> +        has taken place.
>> +      </p>
>> +    </dd>
>> +
>> +    <dt>ct_lb</dt>
>> +    <dd>
>> +      Not yet implemented; currently implemented as a no-op.
>> +    </dd>
>> +
>> +    <dt>put_arp</dt>
>> +    <dt>put_nd</dt>
>> +    <dd>
>> +      This action is treated as a no-op.
>> +    </dd>
>> +  </dl>
>> +
>>    <h2>Summary Output</h2>
>>
>>    <p>
>> diff --git a/ovn/utilities/ovn-trace.c b/ovn/utilities/ovn-trace.c
>> index 3a0780eb931e..860fd4b26be0 100644
>> --- a/ovn/utilities/ovn-trace.c
>> +++ b/ovn/utilities/ovn-trace.c
>> @@ -346,6 +346,8 @@ struct ovntrace_datapath {
>>      size_t n_flows, allocated_flows;
>>
>>      struct hmap mac_bindings;   /* Contains "struct
>> ovntrace_mac_binding"s. */
>> +
>> +    bool has_local_l3gateway;
>>  };
>>
>>  struct ovntrace_port {
>> @@ -570,6 +572,9 @@ read_ports(void)
>>                      port->peer->peer = port;
>>                  }
>>              }
>> +        } else if (!strcmp(sbpb->type, "l3gateway")) {
>> +            /* Treat all gateways as local for our purposes. */
>> +            dp->has_local_l3gateway = true;
>>          }
>>      }
>>
>> @@ -1522,6 +1527,46 @@ execute_ct_next(const struct ovnact_ct_next
>> *ct_next,
>>  }
>>
>>  static void
>> +execute_ct_nat(const struct ovnact_ct_nat *ct_nat,
>> +               const struct ovntrace_datapath *dp, struct flow *uflow,
>> +               enum ovnact_pipeline pipeline, struct ovs_list *super)
>> +{
>> +    bool is_dst = ct_nat->ovnact.type == OVNACT_CT_DNAT;
>> +    if (!is_dst && dp->has_local_l3gateway && !ct_nat->ip) {
>> +        /* "ct_snat;" has no visible effect in a gateway router. */
>> +        return;
>> +    }
>> +    const char *direction = is_dst ? "dst" : "src";
>> +
>> +    /* Make a sub-node for attaching the next table,
>> +     * and figure out the changes if any. */
>> +    struct flow ct_flow = *uflow;
>> +    struct ds s = DS_EMPTY_INITIALIZER;
>> +    ds_put_format(&s, "ct_%cnat", direction[0]);
>> +    if (ct_nat->ip) {
>> +        ds_put_format(&s, "(ip4.%s="IP_FMT")", direction,
>> IP_ARGS(ct_nat->ip));
>> +        ovs_be32 *ip = is_dst ? &ct_flow.nw_dst : &ct_flow.nw_src;
>> +        *ip = ct_nat->ip;
>> +
>> +        uint8_t state = is_dst ? CS_DST_NAT : CS_SRC_NAT;
>> +        ct_flow.ct_state |= state;
>> +    } else {
>> +        ds_put_format(&s, " /* assuming no un-%cnat entry, so no change
>> */",
>> +                      direction[0]);
>> +    }
>> +    struct ovntrace_node *node = ovntrace_node_append(
>> +        super, OVNTRACE_NODE_TRANSFORMATION, "%s", ds_cstr(&s));
>> +    ds_destroy(&s);
>> +
>> +    /* Trace the actions in the next table. */
>> +    trace__(dp, &ct_flow, ct_nat->ltable, pipeline, &node->subs);
>> +
>> +    /* Upon return, we will trace the actions following the ct action in
>> the
>> +     * original table.  The pipeline forked, so we're using the original
>> +     * flow, not ct_flow. */
>> +}
>> +
>> +static void
>>  trace_actions(const struct ovnact *ovnacts, size_t ovnacts_len,
>>                const struct ovntrace_datapath *dp, struct flow *uflow,
>>                uint8_t table_id, enum ovnact_pipeline pipeline,
>> @@ -1585,10 +1630,11 @@ trace_actions(const struct ovnact *ovnacts, size_t
>> ovnacts_len,
>>              break;
>>
>>          case OVNACT_CT_DNAT:
>> +            execute_ct_nat(ovnact_get_CT_DNAT(a), dp, uflow, pipeline,
>> super);
>> +            break;
>> +
>>          case OVNACT_CT_SNAT:
>> -            ovntrace_node_append(super, OVNTRACE_NODE_ERROR,
>> -                                 "*** ct_dnat and ct_snat actions "
>> -                                 "not implemented");
>> +            execute_ct_nat(ovnact_get_CT_SNAT(a), dp, uflow, pipeline,
>> super);
>>              break;
>>
>>          case OVNACT_CT_LB:
>> --
>> 2.10.2
>>
>> _______________________________________________
>> dev mailing list
>> dev at openvswitch.org
>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>>
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