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

Guru Shetty guru at ovn.org
Thu Jun 28 18:45:02 UTC 2018


On 28 June 2018 at 11:44, 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.
>

We have a few test cases. The tests weren't run likely as they are system
tests.


>
> 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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