[ovs-dev] [PATCH v2 2/2 ovn] OVN: Use ipv4.src and ipv4.dst actions for NAT rules

Numan Siddique numans at ovn.org
Mon Oct 28 13:40:12 UTC 2019


On Sat, Oct 5, 2019 at 1:45 AM Ankur Sharma <ankur.sharma at nutanix.com> wrote:
>
> For dnat_and_snat rules which are meant to be stateless
> instead of using ct_snat/dnat OVN actions, we will use
> ipv4.src/ipv4.dst.
>
> This actions will do 1:1 mapping to inner ip to external ip,
> while recalculating the checksums.
>
> Signed-off-by: Ankur Sharma <ankur.sharma at nutanix.com>


Hi Ankur,

There is a checkpatch warning - WARNING: Line is 80 characters long
(recommended limit is 79).
Please address it.

Please see below for few comments.

Thanks
Numan

> ---
>  northd/ovn-northd.8.xml | 34 +++++++++++++++----
>  northd/ovn-northd.c     | 86 +++++++++++++++++++++++++++++++++++++++++++------
>  tests/ovn-northd.at     | 50 ++++++++++++++++++++++++++++
>  3 files changed, 154 insertions(+), 16 deletions(-)
>
> diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> index 0f4f1c1..7d5d102 100644
> --- a/northd/ovn-northd.8.xml
> +++ b/northd/ovn-northd.8.xml
> @@ -1718,7 +1718,9 @@ icmp6 {
>            to change the source IP address of a packet from <var>A</var> to
>            <var>B</var>, a priority-90 flow matches <code>ip &amp;&amp;
>            ip4.dst == <var>B</var></code> with an action
> -          <code>ct_snat; </code>.
> +          <code>ct_snat; </code>. If the NAT rule is of type dnat_and_snat
> +          and has <code>is_stateless=true</code> in the options, then the action
> +          would be <code>replace_dst_ip(<var>B</var>)</code>.

I think you need to update the documentation as you removed the action
- replace_dst_ip in v2.


>          </p>
>
>          <p>
> @@ -1738,7 +1740,10 @@ icmp6 {
>            <var>B</var>, a priority-100 flow matches <code>ip &amp;&amp;
>            ip4.dst == <var>B</var> &amp;&amp; inport == <var>GW</var></code>,
>            where <var>GW</var> is the logical router gateway port, with an
> -          action <code>ct_snat;</code>.
> +          action <code>ct_snat;</code>. If the NAT rule is of type
> +          dnat_and_snat and has <code>is_stateless=true</code> in the
> +          options, then the action would be <code>replace_dst_ip

Same here and other places too.

> +          (<var>B</var>)</code>.
>          </p>
>
>          <p>
> @@ -1858,7 +1863,10 @@ icmp6 {
>          Gateway router is configured to force SNAT any DNATed packet,
>          the above action will be replaced by
>          <code>flags.force_snat_for_dnat = 1; flags.loopback = 1;
> -        ct_dnat(<var>B</var>);</code>.
> +        ct_dnat(<var>B</var>);</code>. If the NAT rule is of type
> +        dnat_and_snat and has <code>is_stateless=true</code> in the
> +        options, then the action would be <code>replace_dst_ip
> +        (<var>B</var>)</code>.
>        </li>
>
>        <li>
> @@ -1890,7 +1898,10 @@ icmp6 {
>            <var>B</var>, a priority-100 flow matches <code>ip &amp;&amp;
>            ip4.dst == <var>B</var> &amp;&amp; inport == <var>GW</var></code>,
>            where <var>GW</var> is the logical router gateway port, with an
> -          action <code>ct_dnat(<var>B</var>);</code>.
> +          action <code>ct_dnat(<var>B</var>);</code>. If the NAT rule is of
> +          type dnat_and_snat and has <code>is_stateless=true</code> in the
> +          options, then the action would be <code>replace_dst_ip
> +          (<var>B</var>)</code>.
>          </p>
>
>          <p>
> @@ -2553,7 +2564,10 @@ nd_ns {
>            matches <code>ip &amp;&amp; ip4.src == <var>B</var>
>            &amp;&amp; outport == <var>GW</var></code>, where <var>GW</var>
>            is the logical router gateway port, with an action
> -          <code>ct_dnat;</code>.
> +          <code>ct_dnat;</code>. If the NAT rule is of type
> +          dnat_and_snat and has <code>is_stateless=true</code> in the
> +          options, then the action would be <code>replace_src_ip
> +          (<var>B</var>)</code>.
>          </p>
>
>          <p>
> @@ -2611,7 +2625,10 @@ nd_ns {
>            <code>ip &amp;&amp; ip4.src == <var>A</var></code> with an action
>            <code>ct_snat(<var>B</var>);</code>.  The priority of the flow
>            is calculated based on the mask of <var>A</var>, with matches
> -          having larger masks getting higher priorities.
> +          having larger masks getting higher priorities. If the NAT rule is
> +          of type dnat_and_snat and has <code>is_stateless=true</code> in the
> +          options, then the action would be <code>replace_src_ip
> +          (<var>B</var>)</code>.
>          </p>
>          <p>
>            A priority-0 logical flow with match <code>1</code> has actions
> @@ -2634,7 +2651,10 @@ nd_ns {
>            logical router gateway port, with an action
>            <code>ct_snat(<var>B</var>);</code>.  The priority of the flow
>            is calculated based on the mask of <var>A</var>, with matches
> -          having larger masks getting higher priorities.
> +          having larger masks getting higher priorities. If the NAT rule
> +          is of type dnat_and_snat and has <code>is_stateless=true</code>
> +          in the options, then the action would be <code>replace_src_ip
> +          (<var>B</var>)</code>.
>          </p>
>
>          <p>
> diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> index f393ceb..4036392 100644
> --- a/northd/ovn-northd.c
> +++ b/northd/ovn-northd.c
> @@ -6314,6 +6314,18 @@ copy_ra_to_sb(struct ovn_port *op, const char *address_mode)
>      smap_destroy(&options);
>  }
>
> +static inline bool
> +lrouter_nat_is_stateless(const struct nbrec_nat *nat)
> +{
> +    const char *is_stateless = smap_get(&nat->options, "is_stateless");
> +
> +    if (is_stateless && !strcmp(is_stateless, "true")) {
> +        return true;
> +    }
> +
> +    return false;
> +}
> +
>  static void
>  build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                      struct hmap *lflows, struct shash *meter_groups)
> @@ -7052,6 +7064,7 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>              nat = od->nbr->nat[i];
>
>              ovs_be32 ip, mask;
> +            bool is_stateless = lrouter_nat_is_stateless(nat);
>
>              char *error = ip_parse_masked(nat->external_ip, &ip, &mask);
>              if (error || mask != OVS_BE32_MAX) {
> @@ -7117,15 +7130,26 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                  if (!od->l3dgw_port) {
>                      /* Gateway router. */
>                      ds_clear(&match);
> +                    ds_clear(&actions);
>                      ds_put_format(&match, "ip && ip4.dst == %s",
>                                    nat->external_ip);
> +
> +                    if (!strcmp(nat->type, "dnat_and_snat") && is_stateless) {
> +                        ds_put_format(&actions, "ip4.dst=%s; next;",
> +                                      nat->logical_ip);
> +                    } else {
> +                        ds_put_cstr(&actions, "ct_snat;");
> +                    }
> +
>                      ovn_lflow_add(lflows, od, S_ROUTER_IN_UNSNAT, 90,
> -                                  ds_cstr(&match), "ct_snat;");
> +                                  ds_cstr(&match), ds_cstr(&actions));
>                  } else {
>                      /* Distributed router. */
>
>                      /* Traffic received on l3dgw_port is subject to NAT. */
>                      ds_clear(&match);
> +                    ds_clear(&actions);
> +
>                      ds_put_format(&match, "ip && ip4.dst == %s"
>                                            " && inport == %s",
>                                    nat->external_ip,
> @@ -7136,8 +7160,16 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                          ds_put_format(&match, " && is_chassis_resident(%s)",
>                                        od->l3redirect_port->json_key);
>                      }
> +
> +                    if (!strcmp(nat->type, "dnat_and_snat") && is_stateless) {
> +                        ds_put_format(&actions, "ip4.dst=%s; next;",
> +                                      nat->logical_ip);
> +                    } else {
> +                        ds_put_cstr(&actions, "ct_snat;");
> +                    }
> +
>                      ovn_lflow_add(lflows, od, S_ROUTER_IN_UNSNAT, 100,
> -                                  ds_cstr(&match), "ct_snat;");
> +                                  ds_cstr(&match), ds_cstr(&actions));
>
>                      /* Traffic received on other router ports must be
>                       * redirected to the central instance of the l3dgw_port
> @@ -7172,8 +7204,16 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                          ds_put_format(&actions,
>                                        "flags.force_snat_for_dnat = 1; ");
>                      }
> -                    ds_put_format(&actions, "flags.loopback = 1; ct_dnat(%s);",
> -                                  nat->logical_ip);
> +
> +                    if (!strcmp(nat->type, "dnat_and_snat") && is_stateless) {
> +                        ds_put_format(&actions, "flags.loopback = 1; "
> +                                      "ip4.dst=%s; next;",
> +                                      nat->logical_ip);
> +                    } else {
> +                        ds_put_format(&actions, "flags.loopback = 1; ct_dnat(%s);",
> +                                      nat->logical_ip);
> +                    }
> +
>                      ovn_lflow_add(lflows, od, S_ROUTER_IN_DNAT, 100,
>                                    ds_cstr(&match), ds_cstr(&actions));
>                  } else {
> @@ -7192,8 +7232,15 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                                        od->l3redirect_port->json_key);
>                      }
>                      ds_clear(&actions);
> -                    ds_put_format(&actions, "ct_dnat(%s);",
> -                                  nat->logical_ip);
> +
> +                    if (!strcmp(nat->type, "dnat_and_snat") && is_stateless) {
> +                        ds_put_format(&actions, "ip4.dst=%s; next;",
> +                                      nat->logical_ip);
> +                    } else {
> +                        ds_put_format(&actions, "ct_dnat(%s);",
> +                                      nat->logical_ip);
> +                    }
> +
>                      ovn_lflow_add(lflows, od, S_ROUTER_IN_DNAT, 100,
>                                    ds_cstr(&match), ds_cstr(&actions));
>
> @@ -7235,7 +7282,14 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                      ds_put_format(&actions, "eth.src = "ETH_ADDR_FMT"; ",
>                                    ETH_ADDR_ARGS(mac));
>                  }
> -                ds_put_format(&actions, "ct_dnat;");
> +
> +                if (!strcmp(nat->type, "dnat_and_snat") && is_stateless) {
> +                    ds_put_format(&actions, "ip4.src=%s; next;",
> +                                  nat->external_ip);
> +                } else {
> +                    ds_put_format(&actions, "ct_dnat;");
> +                }
> +
>                  ovn_lflow_add(lflows, od, S_ROUTER_OUT_UNDNAT, 100,
>                                ds_cstr(&match), ds_cstr(&actions));
>              }
> @@ -7251,7 +7305,14 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                      ds_put_format(&match, "ip && ip4.src == %s",
>                                    nat->logical_ip);
>                      ds_clear(&actions);
> -                    ds_put_format(&actions, "ct_snat(%s);", nat->external_ip);
> +
> +                    if (!strcmp(nat->type, "dnat_and_snat") && is_stateless) {
> +                        ds_put_format(&actions, "ip4.src=%s; next;",
> +                                      nat->external_ip);
> +                    } else {
> +                        ds_put_format(&actions, "ct_snat(%s);",
> +                                      nat->external_ip);
> +                    }
>
>                      /* The priority here is calculated such that the
>                       * nat->logical_ip with the longest mask gets a higher
> @@ -7280,7 +7341,14 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>                          ds_put_format(&actions, "eth.src = "ETH_ADDR_FMT"; ",
>                                        ETH_ADDR_ARGS(mac));
>                      }
> -                    ds_put_format(&actions, "ct_snat(%s);", nat->external_ip);
> +
> +                    if (!strcmp(nat->type, "dnat_and_snat") && is_stateless) {
> +                        ds_put_format(&actions, "ip4.src=%s; next;",
> +                                      nat->external_ip);
> +                    } else {
> +                        ds_put_format(&actions, "ct_snat(%s);",
> +                                      nat->external_ip);
> +                    }
>
>                      /* The priority here is calculated such that the
>                       * nat->logical_ip with the longest mask gets a higher
> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> index 42033d5..64511a9 100644
> --- a/tests/ovn-northd.at
> +++ b/tests/ovn-northd.at
> @@ -966,3 +966,53 @@ OVS_WAIT_UNTIL([ovn-sbctl get Port_Binding ${uuid} options:redirect-type], [0],
>  ])
>
>  AT_CLEANUP
> +

Can you add a new test case or modify an existing test case in ovn.at
to make use of this feature ?

> +AT_SETUP([ovn -- check stateless dnat_and_snat rule])
> +AT_SKIP_IF([test $HAVE_PYTHON = no])
> +ovn_start
> +
> +ovn-sbctl chassis-add gw1 geneve 127.0.0.1
> +
> +ovn-nbctl lr-add R1
> +ovn-nbctl lrp-add R1 R1-S1 02:ac:10:01:00:01 172.16.1.1/24
> +
> +ovn-nbctl ls-add S1
> +ovn-nbctl lsp-add S1 S1-R1
> +ovn-nbctl lsp-set-type S1-R1 router
> +ovn-nbctl lsp-set-addresses S1-R1 router
> +ovn-nbctl --wait=sb lsp-set-options S1-R1 router-port=R1-S1
> +
> +ovn-nbctl lrp-set-gateway-chassis R1-S1 gw1
> +
> +uuid=`ovn-sbctl --columns=_uuid --bare find Port_Binding logical_port=cr-R1-S1`
> +echo "CR-LRP UUID is: " $uuid
> +
> +ovn-nbctl lr-nat-add R1 dnat_and_snat  172.16.1.1 50.0.0.11
> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ct_snat | wc -l], [0], [2
> +])

There is a chance that the test case might fail on slower systems if
ovn-northd is not fast enough to
add the necessary logical flows.

For the above first check, I would suggest to use - OVS_WAIT_UNTIL.


> +
> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ct_dnat | wc -l], [0], [2
> +])
> +
> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ip4.dst=| wc -l], [0], [0
> +])
> +
> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ip4.src=| wc -l], [0], [0
> +])
> +
> +ovn-nbctl lr-nat-del R1 dnat_and_snat  172.16.1.1
> +
> +ovn-nbctl --stateless lr-nat-add R1 dnat_and_snat  172.16.1.1 50.0.0.11
> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ct_snat | wc -l], [0], [0
> +])
> +

Same here. Please use OVS_WAIT_UNTIL.


> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ct_dnat | wc -l], [0], [0
> +])
> +
> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ip4.dst=| wc -l], [0], [2
> +])
> +
> +AT_CHECK([ovn-sbctl dump-flows R1 | grep ip4.src=| wc -l], [0], [2
> +])
> +
> +AT_CLEANUP
> --
> 1.8.3.1
>
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