[ovs-dev] [External] : [PATCH ovn v2] ovn-northd.c: Add proxy ARP support to OVN

Numan Siddique numans at ovn.org
Tue Jun 15 13:33:16 UTC 2021


On Tue, Jun 15, 2021 at 8:34 AM Brendan Doyle <brendan.doyle at oracle.com> wrote:
>
>
>
> On 15/06/2021 13:26, Numan Siddique wrote:
> > On Tue, Jun 15, 2021 at 7:50 AM Brendan Doyle <brendan.doyle at oracle.com> wrote:
> >>
> >>
> >> On 14/06/2021 21:17, Numan Siddique wrote:
> >>> On Mon, Jun 14, 2021 at 5:19 AM Brendan Doyle <brendan.doyle at oracle.com> wrote:
> >>>> Hi,
> >>>>
> >>>> Just wondering how to move this along. It's been in the queue a while now.
> >>>> The product I'm working on requires this feature and If I can't get it
> >>>> upstream
> >>>> I'll need to look at other options.
> >>> Hi Brendan,
> >>>
> >>> Sorry for the late reply.  For some reason the patch doesn't apply to me.
> >> Sorry I'm not sure what you mean, the patch did not apply, it works when
> >> I apply
> >> to my repo?
> >>> Please see below for a few comments.
> >>>
> >>>
> >>>> Thanks
> >>>>
> >>>> Brendan
> >>>>
> >>>> On 04/06/2021 15:51, Brendan Doyle wrote:
> >>>>>   From 07ecd5d00f82658e094132102575d8d576161a6b Mon Sep 17 00:00:00 2001
> >>>>> From: Brendan Doyle <brendan.doyle at oracle.com>
> >>>>> Date: Fri, 28 May 2021 10:01:17 -0700
> >>>>> Subject: [PATCH ovn] ovn-northd.c: Add proxy ARP support to OVN
> >>>>>
> >>>>> This patch provides the ability to configure proxy ARP IPs on a Logical
> >>>>> Switch Router port. The IPs are added as Options for router ports. This
> >>>>> provides a useful feature where traffic for a service must be sent to an
> >>>>> address in a logical network address space, but the service is provided
> >>>>> in a different network. For example an NFS service is provide to Logical
> >>>>> networks at an address in their Logical network space, but the NFS
> >>>>> server resides in a physical network. A Logical switch Router port can
> >>>>> be configured to respond to ARP requests sent to the service "Logical
> >>>>> address", the Logical Router/Gateway can then be configured to forward
> >>>>> the traffic to the underlay/physical network.
> >>>>>
> >>>>> Signed-off-by: Brendan Doyle <brendan.doyle at oracle.com>
> >>>>> ---
> >>>>>    northd/ovn-northd.c |  44 ++++++++++++++++++++++
> >>>>>    ovn-nb.xml          |   9 +++++
> >>>>>    tests/ovn.at        | 103
> >>>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>>>>    3 files changed, 156 insertions(+)
> >>>>>
> >>>>> diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> >>>>> index 0e5092a..9b686d9 100644
> >>>>> --- a/northd/ovn-northd.c
> >>>>> +++ b/northd/ovn-northd.c
> >>>>> @@ -6943,6 +6943,7 @@ build_lswitch_arp_nd_responder_known_ips(struct
> >>>>> ovn_port *op,
> >>>>>                                             struct ds *match)
> >>>>>    {
> >>>>>        if (op->nbsp) {
> >>>>> +        const char *arp_proxy;
> >>>>>            if (!strcmp(op->nbsp->type, "virtual")) {
> >>>>>                /* Handle
> >>>>>                 *  - GARPs for virtual ip which belongs to a logical port
> >>>>> @@ -7096,6 +7097,49 @@ build_lswitch_arp_nd_responder_known_ips(struct
> >>>>> ovn_port *op,
> >>>>>                    }
> >>>>>                }
> >>>>>            }
> >>>>> +
> >>>>> +        /*
> >>>>> +         * Add responses for ARP proxies.
> >>>>> +         */
> >>>>> +        arp_proxy = smap_get(&op->nbsp->options,"arp_proxy");
> >>> In my opinion instead of defining these proxy IPs in the logical
> >>> switch port options,
> >>> it is better to define them in the router port as generally a router
> >>> would handle proxy arps (correct me if I'm wrong here).
> >>>
> >>> I'd suggest to add a new column "proxy_ips" (or something more appropriate)
> >>> in the Logical_Router_Port and this column would point to an address set.
> >>>
> >>> CMS can define the list of IPs in the address set.  ovn-northd can add
> >>> a logical flow like
> >>>
> >>> match = "inport == <router_port> && arp.tpa == $proxy_ip, action = {....}
> >>> This would result in just one logical flow.
> >>>
> >>> CMS would do something like
> >>>
> >>> addr_set_uuid=$(ovn-nbctl create address_set name=proxy_arps
> >>> addresses="10.0.0.4, 10.0.0.5")
> >>> ovn-nbctl set logical_router_port <router_port> proxy_ip=$addr_set_uuid
> >>>
> >>> What do you think ?
> >> In both cases only one OVS flows is created (after I made the changes)
> >> suggested by Dan.
> >> I can see the point with respect to proxy ARP and routers, in physical
> >> equipment proxy ARP is done
> >> by routers.  But I think doing the proxy ARP on the LRP of the LS is
> >> consistent with the use of
> >> the "options : nat-addresses" entry in the Logical_Switch_Port TABLE .
> >> The patch makes it clear
> >> that this feature is associated with a router, It is after all in the
> >> "Options  for router ports". I think
> >> it is also more efficient in that we'd respond to the ARP request
> >> earlier in the datapath flows.
> > Even if the proxy arps are associated with a router port, the flows can still be
> > added in the logical switch pipeline of the peer to avoid the extra hop from
> > logical switch pipeline to router pipeline.
> >
> > In my opinion,  it is better that the proxy arps are associated with a
> > router port
> > rather than a logical switch peer port.  Also having a separate column makes
> > more sense to me than defining a string of IP addresses in the options smap.
> I see your point, but  "options : nat-addresses" is a list of IPs on a
> router peer
> port so it is at least consistent with that. Like "options :
> nat-addresses" I don't
> expect it to be a large list.

Ok.  I'd have no objections if other reviewers are fine.

Please see below for one comment.

Thanks
Numan

> > I defer to other reviewers if they are fine with your patch.
>
> Ok thanks.
> > Thanks
> > Numan
> >
> >> The suggestion you make is a lot more involved, touching much more code
> >> and changes the DB
> >> schema, so I'm hesitant to go down that path.
> >>
> >> Brendan.
> >>
> >>> Thanks
> >>> Numan
> >>>
> >>>>> +        if (arp_proxy && op->peer) {
> >>>>> +            char *ips, *ip, *rest;
> >>>>> +            int i = 0;
> >>>>> +
> >>>>> +            ips = xstrdup(arp_proxy);
> >>>>> +            rest = ips;
> >>>>> +
> >>>>> +            /*
> >>>>> +             * Match rule on all proxy ARP IPs.
> >>>>> +             */
> >>>>> +            ds_clear(match);
> >>>>> +            ds_put_cstr(match, "arp.op == 1 && (");
> >>>>> +            while ((ip = strtok_r(rest,",", &rest))) {
> >>>>> +                if (i++ > 0) {
> >>>>> +                        ds_put_cstr(match, " || ");
> >>>>> +                };
> >>>>> +                ds_put_format(match, "arp.tpa == %s", ip);
> >>>>> +            }
> >>>>> +            ds_put_cstr(match, ")");

Instead of the above while loop please make use of the util function -
extract_ip_address()


> >>>>> +
> >>>>> +            ds_clear(actions);
> >>>>> +            ds_put_format(actions,
> >>>>> +                "eth.dst = eth.src; "
> >>>>> +                "eth.src = %s; "
> >>>>> +                "arp.op = 2; /* ARP reply */ "
> >>>>> +                "arp.tha = arp.sha; "
> >>>>> +                "arp.sha = %s; "
> >>>>> +                "arp.tpa <-> arp.spa; "
> >>>>> +                "outport = inport; "
> >>>>> +                "flags.loopback = 1; "
> >>>>> +                "output;",
> >>>>> +                op->peer->lrp_networks.ea_s,
> >>>>> +                op->peer->lrp_networks.ea_s);
> >>>>> +
> >>>>> +            ovn_lflow_add_with_hint(lflows, op->od,
> >>>>> S_SWITCH_IN_ARP_ND_RSP,
> >>>>> +                50, ds_cstr(match), ds_cstr(actions),
> >>>>> &op->nbsp->header_);
> >>>>> +            free(ips);
> >>>>> +        }
> >>>>>        }
> >>>>>    }
> >>>>>
> >>>>> diff --git a/ovn-nb.xml b/ovn-nb.xml
> >>>>> index 02fd216..4b6c183 100644
> >>>>> --- a/ovn-nb.xml
> >>>>> +++ b/ovn-nb.xml
> >>>>> @@ -848,6 +848,15 @@
> >>>>>                </dd>
> >>>>>              </dl>
> >>>>>            </column>
> >>>>> +
> >>>>> +        <column name="options" key="arp_proxy">
> >>>>> +          Optional. A comma separated list IPv4 addresses that this
> >>>>> +          logical switch <code>router</code> port will reply to ARP
> >>>>> requests.
> >>>>> +          Example: <code>169.254.239.254,169.254.239.2</code>. The
> >>>>> +          <ref column="options" key="router-port"/>'s logical router
> >>>>> should
> >>>>> +          have a route to forward packets sent to configured proxy
> >>>>> ARP IPs to
> >>>>> +          an appropriate destination.
> >>>>> +        </column>
> >>>>>          </group>
> >>>>>
> >>>>>          <group title="Options for localnet ports">
> >>>>> diff --git a/tests/ovn.at b/tests/ovn.at
> >>>>> index 2c3c36d..4befe4a 100644
> >>>>> --- a/tests/ovn.at
> >>>>> +++ b/tests/ovn.at
> >>>>> @@ -26527,3 +26527,106 @@ AT_CHECK([test $(ovn-appctl -t
> >>>>> ovn-controller coverage/read-counter lflow_run) =
> >>>>>    OVN_CLEANUP([hv1])
> >>>>>    AT_CLEANUP
> >>>>>    ])
> >>>>> +
> >>>>> +OVN_FOR_EACH_NORTHD([
> >>>>> +AT_SETUP([ovn -- proxy-arp: 1 HVs, 1 LSs, 1 lport/LS, 1 LR])
> >>>>> +AT_KEYWORDS([proxy-arp])
> >>>>> +ovn_start
> >>>>> +
> >>>>> +# Logical network:
> >>>>> +# One LR - lr1 has switch ls1 (192.16.1.0/24) connected to it,
> >>>>> +# and and one HV with IP 192.16.1.6.
> >>>>> +
> >>>>> +ovn-nbctl lr-add lr1
> >>>>> +ovn-nbctl ls-add ls1
> >>>>> +
> >>>>> +# Connect ls1 to lr1
> >>>>> +ovn-nbctl lrp-add lr1 ls1 00:00:00:01:02:f1 192.16.1.1/24
> >>>>> +ovn-nbctl lsp-add ls1 rp-ls1 -- set Logical_Switch_Port rp-ls1 \
> >>>>> +    type=router options:router-port=ls1 addresses=\"00:00:00:01:02:f1\"
> >>>>> +
> >>>>> +# Create logical port ls1-lp1 in ls1
> >>>>> +ovn-nbctl lsp-add ls1 ls1-lp1 \
> >>>>> +-- lsp-set-addresses ls1-lp1 "00:00:00:01:02:03 192.16.1.6"
> >>>>> +
> >>>>> +
> >>>>> +# Create one hypervisor and create OVS ports corresponding to logical
> >>>>> ports.
> >>>>> +net_add n1
> >>>>> +
> >>>>> +sim_add pa-hv
> >>>>> +as pa-hv
> >>>>> +ovs-vsctl add-br br-phys
> >>>>> +ovn_attach n1 br-phys 192.16.0.1
> >>>>> +
> >>>>> +# Note: tx/rx are with respect to the LS port, so
> >>>>> +# tx on switch port is HV rx, etc.
> >>>>> +ovs-vsctl -- add-port br-int vif1 -- \
> >>>>> +    set interface vif1 external-ids:iface-id=ls1-lp1 \
> >>>>> +    options:tx_pcap=pa-hv/vif1-tx.pcap \
> >>>>> +    options:rxq_pcap=pa-hv/vif1-rx.pcap \
> >>>>> +    ofport-request=1
> >>>>> +
> >>>>> +# And proxy ARP flows for 69.254.239.254 and 169.254.239.2
> >>>>> +# and check that SB flows have been added.
> >>>>> +ovn-nbctl --wait=hv add Logical_Switch_Port rp-ls1 \
> >>>>> +options arp_proxy='"169.254.239.254,169.254.239.2"'
> >>>>> +ovn-sbctl dump-flows > sbflows
> >>>>> +AT_CAPTURE_FILE([sbflows])
> >>>>> +
> >>>>> +AT_CHECK([ovn-sbctl dump-flows | grep ls_in_arp_rsp | grep
> >>>>> "169.254.239.2" | wc -l], [0], [dnl
> >>>>> +1
> >>>>> +])
> >>>>> +
> >>>>> +# Remove and check that the flows have been removed
> >>>>> +ovn-nbctl --wait=hv remove Logical_Switch_Port rp-ls1 options
> >>>>> arp_proxy='"169.254.239.254,169.254.239.2"'
> >>>>> +
> >>>>> +AT_CHECK([ovn-sbctl dump-flows | grep ls_in_arp_rsp | grep
> >>>>> "169.254.239.2" | wc -l], [0], [dnl
> >>>>> +0
> >>>>> +])
> >>>>> +
> >>>>> +# Add the flows back send arp request and check we see an ARP response
> >>>>> +ovn-nbctl --wait=hv add Logical_Switch_Port rp-ls1 \
> >>>>> +options arp_proxy='"169.254.239.254,169.254.239.2"'
> >>>>> +
> >>>>> +ls1_p1_mac=00:00:00:01:02:03
> >>>>> +ls1_p1_ip=192.16.1.6
> >>>>> +
> >>>>> +ls1_ro_mac=00:00:00:01:02:f1
> >>>>> +ls1_ro_ip=192.168.1.1
> >>>>> +
> >>>>> +proxy_ip1=169.254.239.254
> >>>>> +proxy_ip2=169.254.239.2
> >>>>> +
> >>>>> +bcast_mac=ff:ff:ff:ff:ff:ff
> >>>>> +
> >>>>> +# Send ARP request for 169.254.239.254
> >>>>> +packet="inport==\"ls1-lp1\" && eth.src==$ls1_p1_mac &&
> >>>>> eth.dst==$bcast_mac &&
> >>>>> +       arp.op==1 && arp.sha==$ls1_p1_mac && arp.spa==$ls1_p1_ip &&
> >>>>> +       arp.tha==$bcast_mac && arp.tpa==$proxy_ip1"
> >>>>> +
> >>>>> +as pa-hv ovs-appctl -t ovn-controller inject-pkt "$packet"
> >>>>> +
> >>>>> +ovs-ofctl dump-flows br-int| grep 169.254.239.254 | grep priority=50
> >>>>>> debug1
> >>>>> +AT_CAPTURE_FILE([debug1])
> >>>>> +
> >>>>> +
> >>>>> +# Check if packet hit the ARP reply ovs flow
> >>>>> +AT_CHECK([ovs-ofctl dump-flows br-int | \
> >>>>> +    grep "169.254.239.254" | \
> >>>>> +    grep "priority=50" | \
> >>>>> +    grep "arp_op=1" | \
> >>>>> +    grep "n_packets=1" | wc -l], [0], [dnl
> >>>>> +1
> >>>>> +])
> >>>>> +
> >>>>> +# Check that the HV gets an ARP reply
> >>>>> +expected="eth.src==$ls1_ro_mac && eth.dst==$ls1_p1_mac &&
> >>>>> +       arp.op==2 && arp.sha==$ls1_ro_mac && arp.spa==$proxy_ip1 &&
> >>>>> +       arp.tha==$ls1_p1_mac && arp.tpa==$ls1_p1_ip"
> >>>>> +echo $expected | ovstest test-ovn expr-to-packets > expected
> >>>>> +
> >>>>> +OVN_CHECK_PACKETS([pa-hv/vif1-tx.pcap], [expected])
> >>>>> +
> >>>>> +OVN_CLEANUP([pa-hv])
> >>>>> +AT_CLEANUP
> >>>>> +])
> >>>> _______________________________________________
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