[ovs-dev] [patch v2] ovn: Fix gateway load balancing.

Darrell Ball dlu998 at gmail.com
Thu Jun 28 18:46:13 UTC 2018


On Thu, Jun 28, 2018 at 11:44 AM, Han Zhou <zhouhan at gmail.com> wrote:

> Hi Mark, what I meant is the test for the feature of LB in Gateway. If we
> had a test case, the problem would have been noticed when Lorenzo is
> working on ICMP feature.
>

Here are tests:

system-ovn

113: ovn -- 2 LRs connected via LS, gateway router, SNAT and DNAT ok
114: ovn -- 2 LRs connected via LS, gateway router, easy SNAT FAILED (
system-ovn.at:262)
115: ovn -- multiple gateway routers, SNAT and DNAT  FAILED (
system-ovn.at:432)
116: ovn -- load-balancing                           ok
117: ovn -- load-balancing - same subnet.            ok
118: ovn -- load balancing in gateway router         ok
119: ovn -- multiple gateway routers, load-balancing FAILED (
system-ovn.at:1051)
120: ovn -- load balancing in router with gateway router port ok
121: ovn -- DNAT and SNAT on distributed router - N/S FAILED (
system-ovn.at:1344)
122: ovn -- DNAT and SNAT on distributed router - E/W FAILED (
system-ovn.at:1517)




>
> On Thu, Jun 28, 2018 at 11:29 AM, Mark Michelson <mmichels at redhat.com>
> wrote:
>
>> Lorenzo actually brought up in today's OVN IRC meeting that writing ICMP
>> tests for IPv6 is problematic right now. IPv4 tests have an M4 macro called
>> OVN_POPULATE_ARP that they call. This manually populates tables in OVS so
>> that there are no ARP requests being sent during the test. It does this by
>> calling `ovs-appct tnl/neigh/set` for each IP address-MAC pair.
>>
>> IPv6 does not have an equivalent. The result is that tests will sometimes
>> succeed, but sometimes will fail because IPv6 ND requests will be sent
>> during the test. I haven't looked into this myself, but Lorenzo mentioned
>> that there would need to be changes made to OVS itself in order to have an
>> IPv6 version of a working OVN_POPULATE_ARP.
>>
>> On 06/28/2018 02:16 PM, Han Zhou wrote:
>>
>>> Agree with Mark that ICMP is still needed for non VIP on gateway. But LB
>>> feature on GW is also important.
>>> Shall we have a test case to cover this particular scenario?
>>>
>>> On Thu, Jun 28, 2018 at 9:41 AM, Mark Michelson <mmichels at redhat.com
>>> <mailto:mmichels at redhat.com>> wrote:
>>>
>>>     Hi Darrell,
>>>
>>>     I'm not 100% sure this is correct. I think this change would only be
>>>     correct if the router's IP addresses are also load balancer VIPs. In
>>>     the case where the VIPs do not overlap with the router IP addresses,
>>>     I think we'd want to have the ICMP responses still in place.
>>>
>>>
>>>     On 06/28/2018 01:15 AM, Darrell Ball wrote:
>>>
>>>         Non-distributed and distributed gateway load balancing is broken.
>>>         Recent changes for port unreachable handling broke the associated
>>>         unsnat functionality.  The fix approach is check for gateway
>>>         contexts and accept packets directed to gateway router IPs.
>>>
>>>         Fixes:  86558ac2e476 ("OVN: add UDP port unreachable support to
>>>         OVN logical router.")
>>>         Fixes:  159932c9e4ea ("OVN: add TCP port unreachable support to
>>>         OVN logical router.")
>>>         Fixes:  0e858e05f76b ("OVN: add protocol unreachable support to
>>>         OVN router ports.")
>>>         CC: Lorenzo Bianconi <lorenzo.bianconi at redhat.com
>>>         <mailto:lorenzo.bianconi at redhat.com>>
>>>         Signed-off-by: Darrell Ball <dlu998 at gmail.com
>>>         <mailto:dlu998 at gmail.com>>
>>>
>>>         ---
>>>            ovn/northd/ovn-northd.8.xml |  17 ++++---
>>>            ovn/northd/ovn-northd.c     | 106
>>>         ++++++++++++++++++++++----------------------
>>>            2 files changed, 64 insertions(+), 59 deletions(-)
>>>
>>>         diff --git a/ovn/northd/ovn-northd.8.xml
>>>         b/ovn/northd/ovn-northd.8.xml
>>>         index cfd3511..280efd0 100644
>>>         --- a/ovn/northd/ovn-northd.8.xml
>>>         +++ b/ovn/northd/ovn-northd.8.xml
>>>         @@ -1310,8 +1310,9 @@ nd_na {
>>>                    <p>
>>>                      UDP port unreachable.  Priority-80 flows generate
>>>         ICMP port
>>>                      unreachable messages in reply to UDP datagrams
>>>         directed to the
>>>         -          router's IP address.  The logical router doesn't
>>>         accept any UDP
>>>         -          traffic so it always generates such a reply.
>>>         +          router's IP address, except in the special case of
>>>         gateways,
>>>         +          which accept traffic directed to a router IP for load
>>>         balancing
>>>         +          purposes.
>>>                    </p>
>>>                      <p>
>>>         @@ -1321,10 +1322,10 @@ nd_na {
>>>                    <li>
>>>                    <p>
>>>         -          TCP reset.  Priority-80 flows generate TCP reset
>>>         messages in reply to
>>>         -          TCP datagrams directed to the router's IP address.
>>>      The logical
>>>         -          router doesn't accept any TCP traffic so it always
>>>         generates such a
>>>         -          reply.
>>>         +          TCP reset.  Priority-80 flows generate TCP reset
>>>         messages in reply
>>>         +          to TCP datagrams directed to the router's IP address,
>>>         except in
>>>         +          the special case of gateways, which accept traffic
>>>         directed to a
>>>         +          router IP for load balancing purposes.
>>>                    </p>
>>>                      <p>
>>>         @@ -1336,7 +1337,9 @@ nd_na {
>>>                    <p>
>>>                      Protocol unreachable.  Priority-70 flows generate
>>>         ICMP protocol
>>>                      unreachable messages in reply to packets directed
>>>         to the router's IP
>>>         -          address on IP protocols other than UDP, TCP, and ICMP.
>>>         +          address on IP protocols other than UDP, TCP, and
>>>         ICMP, except in the
>>>         +          special case of gateways, which accept traffic
>>>         directed to a router
>>>         +          IP for load balancing purposes.
>>>                    </p>
>>>                      <p>
>>>         diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
>>>         index 72fe4e7..7648bce 100644
>>>         --- a/ovn/northd/ovn-northd.c
>>>         +++ b/ovn/northd/ovn-northd.c
>>>         @@ -5141,48 +5141,49 @@ build_lrouter_flows(struct hmap
>>>         *datapaths, struct hmap *ports,
>>>                                      ds_cstr(&match), ds_cstr(&actions));
>>>                    }
>>>            -        /* UDP/TCP port unreachable */
>>>         -        for (int i = 0; i < op->lrp_networks.n_ipv4_addrs; i++)
>>> {
>>>         -            const char *action;
>>>         -
>>>         -            ds_clear(&match);
>>>         -            ds_put_format(&match,
>>>         -                          "ip4 && ip4.dst == %s &&
>>>         !ip.later_frag && udp",
>>>         -                          op->lrp_networks.ipv4_addrs[i]
>>> .addr_s);
>>>         -            action = "icmp4 {"
>>>         -                        "eth.dst <-> eth.src; "
>>>         -                        "ip4.dst <-> ip4.src; "
>>>         -                        "ip.ttl = 255; "
>>>         -                        "icmp4.type = 3; "
>>>         -                        "icmp4.code = 3; "
>>>         -                        "next; };";
>>>         -            ovn_lflow_add(lflows, op->od, S_ROUTER_IN_IP_INPUT,
>>> 80,
>>>         -                          ds_cstr(&match), action);
>>>         +        if (!smap_get(&op->od->nbr->options, "chassis")
>>>         +            && !op->od->l3dgw_port) {
>>>         +            /* UDP/TCP port unreachable. */
>>>         +            for (int i = 0; i < op->lrp_networks.n_ipv4_addrs;
>>>         i++) {
>>>         +                ds_clear(&match);
>>>         +                ds_put_format(&match,
>>>         +                              "ip4 && ip4.dst == %s &&
>>>         !ip.later_frag && udp",
>>>         +
>>>  op->lrp_networks.ipv4_addrs[i].addr_s);
>>>         +                const char *action = "icmp4 {"
>>>         +                                     "eth.dst <-> eth.src; "
>>>         +                                     "ip4.dst <-> ip4.src; "
>>>         +                                     "ip.ttl = 255; "
>>>         +                                     "icmp4.type = 3; "
>>>         +                                     "icmp4.code = 3; "
>>>         +                                     "next; };";
>>>         +                ovn_lflow_add(lflows, op->od,
>>>         S_ROUTER_IN_IP_INPUT, 80,
>>>         +                              ds_cstr(&match), action);
>>>            -            ds_clear(&match);
>>>         -            ds_put_format(&match,
>>>         -                          "ip4 && ip4.dst == %s &&
>>>         !ip.later_frag && tcp",
>>>         -                          op->lrp_networks.ipv4_addrs[i]
>>> .addr_s);
>>>         -            action = "tcp_reset {"
>>>         -                        "eth.dst <-> eth.src; "
>>>         -                        "ip4.dst <-> ip4.src; "
>>>         -                        "next; };";
>>>         -            ovn_lflow_add(lflows, op->od, S_ROUTER_IN_IP_INPUT,
>>> 80,
>>>         -                          ds_cstr(&match), action);
>>>         +                ds_clear(&match);
>>>         +                ds_put_format(&match,
>>>         +                              "ip4 && ip4.dst == %s &&
>>>         !ip.later_frag && tcp",
>>>         +
>>>  op->lrp_networks.ipv4_addrs[i].addr_s);
>>>         +                action = "tcp_reset {"
>>>         +                         "eth.dst <-> eth.src; "
>>>         +                         "ip4.dst <-> ip4.src; "
>>>         +                         "next; };";
>>>         +                ovn_lflow_add(lflows, op->od,
>>>         S_ROUTER_IN_IP_INPUT, 80,
>>>         +                              ds_cstr(&match), action);
>>>            -            ds_clear(&match);
>>>         -            ds_put_format(&match,
>>>         -                          "ip4 && ip4.dst == %s &&
>>> !ip.later_frag",
>>>         -                          op->lrp_networks.ipv4_addrs[i]
>>> .addr_s);
>>>         -            action = "icmp4 {"
>>>         -                        "eth.dst <-> eth.src; "
>>>         -                        "ip4.dst <-> ip4.src; "
>>>         -                        "ip.ttl = 255; "
>>>         -                        "icmp4.type = 3; "
>>>         -                        "icmp4.code = 2; "
>>>         -                        "next; };";
>>>         -            ovn_lflow_add(lflows, op->od, S_ROUTER_IN_IP_INPUT,
>>> 70,
>>>         -                          ds_cstr(&match), action);
>>>         +                ds_clear(&match);
>>>         +                ds_put_format(&match,
>>>         +                              "ip4 && ip4.dst == %s &&
>>>         !ip.later_frag",
>>>         +
>>>  op->lrp_networks.ipv4_addrs[i].addr_s);
>>>         +                action = "icmp4 {"
>>>         +                         "eth.dst <-> eth.src; "
>>>         +                         "ip4.dst <-> ip4.src; "
>>>         +                         "ip.ttl = 255; "
>>>         +                         "icmp4.type = 3; "
>>>         +                         "icmp4.code = 2; "
>>>         +                         "next; };";
>>>         +                ovn_lflow_add(lflows, op->od,
>>>         S_ROUTER_IN_IP_INPUT, 70,
>>>         +                              ds_cstr(&match), action);
>>>         +            }
>>>                    }
>>>                      ds_clear(&match);
>>>         @@ -5306,19 +5307,20 @@ build_lrouter_flows(struct hmap
>>>         *datapaths, struct hmap *ports,
>>>                    }
>>>                      /* TCP port unreachable */
>>>         -        for (int i = 0; i < op->lrp_networks.n_ipv6_addrs; i++)
>>> {
>>>         -            const char *action;
>>>         -
>>>         -            ds_clear(&match);
>>>         -            ds_put_format(&match,
>>>         -                          "ip6 && ip6.dst == %s &&
>>>         !ip.later_frag && tcp",
>>>         -                          op->lrp_networks.ipv6_addrs[i]
>>> .addr_s);
>>>         -            action = "tcp_reset {"
>>>         -                        "eth.dst <-> eth.src; "
>>>         -                        "ip6.dst <-> ip6.src; "
>>>         -                        "next; };";
>>>         -            ovn_lflow_add(lflows, op->od, S_ROUTER_IN_IP_INPUT,
>>> 80,
>>>         +        if (!smap_get(&op->od->nbr->options, "chassis")
>>>         +            && !op->od->l3dgw_port) {
>>>         +            for (int i = 0; i < op->lrp_networks.n_ipv6_addrs;
>>>         i++) {
>>>         +                ds_clear(&match);
>>>         +                ds_put_format(&match,
>>>         +                              "ip6 && ip6.dst == %s &&
>>>         !ip.later_frag && tcp",
>>>         +
>>>  op->lrp_networks.ipv6_addrs[i].addr_s);
>>>         +                const char *action = "tcp_reset {"
>>>         +                                     "eth.dst <-> eth.src; "
>>>         +                                     "ip6.dst <-> ip6.src; "
>>>         +                                     "next; };";
>>>         +                ovn_lflow_add(lflows, op->od,
>>>         S_ROUTER_IN_IP_INPUT, 80,
>>>                                      ds_cstr(&match), action);
>>>         +            }
>>>                    }
>>>                }
>>>
>>>
>>>     _______________________________________________
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>>>     dev at openvswitch.org <mailto:dev at openvswitch.org>
>>>     https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>>>     <https://mail.openvswitch.org/mailman/listinfo/ovs-dev>
>>>
>>>
>>>
>>
>


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