[ovs-dev] [PATCH ovn v8 2/5] northd: make connected routes have higher priority than static

Numan Siddique numans at ovn.org
Wed Nov 17 17:57:31 UTC 2021


On Wed, Nov 17, 2021 at 9:24 AM Vladislav Odintsov <odivlad at gmail.com> wrote:
>
> Two additions:
>
> 1. Regarding documentation for flow in lr_in_defrag section:
>
> It seems to me that documentation for it is written in a wrong section (lr_in_defrag).
> Since the flow is installed in lr_in_ip_routing, it should be documented there.
> I’ll move it if you don’t mind.

Sure.  Thanks.  I'd suggest having a separate patch for fixing the
documentation.
>
>
> 2. Documentation for other flow changes was added, but I’ve committed it to a wrong patch (#3).
> I’ll move documentation update between patches.

Ack.

Thanks
Numan

>
> Regards,
> Vladislav Odintsov
>
> > On 17 Nov 2021, at 13:51, Vladislav Odintsov <odivlad at gmail.com> wrote:
> >
> > Hi Numan,
> >
> > Thanks for the review.
> > Sure I will fix this. Should I wait for more comments or that’s all and I can send v9?
> >
> > Regards,
> > Vladislav Odintsov
> >
> >> On 17 Nov 2021, at 05:17, Numan Siddique <numans at ovn.org> wrote:
> >>
> >> On Sat, Nov 13, 2021 at 4:44 AM Vladislav Odintsov <odivlad at gmail.com <mailto:odivlad at gmail.com>> wrote:
> >>>
> >>> With this patch routes to connected networks have higher
> >>> priority than static routes with same ip_prefix.
> >>>
> >>> This brings commonly-used behaviour for routes lookup order:
> >>> 1: longest prefix match
> >>> 2: metric
> >>>
> >>> The metric has next lookup order:
> >>> 1: connected routes
> >>> 2: static routes
> >>>
> >>> Earlier static and connected routes with same ip_prefix had
> >>> the same priority, so it was impossible to predict which one
> >>> is used for routing decision.
> >>>
> >>> Each route's prefix length has its own 'slot' in lflow prios.
> >>> Now prefix length space is calculated using next information:
> >>> to calculate route's priority prefixlen multiplied by 3
> >>> + route origin offset (0 - source-based route; 1 - directly-
> >>> connected route; 2 - static route).
> >>>
> >>> Also, enlarge prio for generic records in lr_in_ip_routing stage
> >>> by 10000.
> >>>
> >>> Signed-off-by: Vladislav Odintsov <odivlad at gmail.com>
> >>
> >> Hi Vladislav,
> >>
> >> Thanks for the patch.  Overall it looks good to me.  I've one comment.
> >> Looks like the documentation updated in ovn-northd.8.xml is not accurate.
> >>
> >> This patch modifies the flows in the lr_in_ip_routing stage but this
> >> patch doesn't update the documentation.
> >> Also the patch updates the documentation for the flow in lr_in_defrag
> >> stage, which seems not correct.
> >>
> >> Can you please update the documentation accurately ?
> >>
> >> Numan
> >>
> >>> ---
> >>> northd/northd.c         | 50 ++++++++++++++++++++++++++++-------------
> >>> northd/ovn-northd.8.xml | 12 +++++-----
> >>> tests/ovn-northd.at     |  8 +++----
> >>> 3 files changed, 45 insertions(+), 25 deletions(-)
> >>>
> >>> diff --git a/northd/northd.c b/northd/northd.c
> >>> index 1e8a3457c..0d513f039 100644
> >>> --- a/northd/northd.c
> >>> +++ b/northd/northd.c
> >>> @@ -305,6 +305,15 @@ enum ovn_stage {
> >>> *
> >>> */
> >>>
> >>> +/*
> >>> + * Route offsets implement logic to prioritize traffic for routes with
> >>> + * same ip_prefix values:
> >>> + *  -  connected route overrides static one;
> >>> + *  -  static route overrides connected route. */
> >>> +#define ROUTE_PRIO_OFFSET_MULTIPLIER 3
> >>> +#define ROUTE_PRIO_OFFSET_STATIC 1
> >>> +#define ROUTE_PRIO_OFFSET_CONNECTED 2
> >>> +
> >>> /* Returns an "enum ovn_stage" built from the arguments. */
> >>> static enum ovn_stage
> >>> ovn_stage_build(enum ovn_datapath_type dp_type, enum ovn_pipeline pipeline,
> >>> @@ -8782,6 +8791,7 @@ struct ecmp_groups_node {
> >>>    struct in6_addr prefix;
> >>>    unsigned int plen;
> >>>    bool is_src_route;
> >>> +    const char *origin;
> >>>    uint16_t route_count;
> >>>    struct ovs_list route_list; /* Contains ecmp_route_list_node */
> >>> };
> >>> @@ -8819,6 +8829,7 @@ ecmp_groups_add(struct hmap *ecmp_groups,
> >>>    eg->prefix = route->prefix;
> >>>    eg->plen = route->plen;
> >>>    eg->is_src_route = route->is_src_route;
> >>> +    eg->origin = smap_get_def(&route->route->options, "origin", "");
> >>>    ovs_list_init(&eg->route_list);
> >>>    ecmp_groups_add_route(eg, route);
> >>>
> >>> @@ -8919,19 +8930,20 @@ build_route_prefix_s(const struct in6_addr *prefix, unsigned int plen)
> >>> static void
> >>> build_route_match(const struct ovn_port *op_inport, const char *network_s,
> >>>                  int plen, bool is_src_route, bool is_ipv4, struct ds *match,
> >>> -                  uint16_t *priority)
> >>> +                  uint16_t *priority, int ofs)
> >>> {
> >>>    const char *dir;
> >>>    /* The priority here is calculated to implement longest-prefix-match
> >>>     * routing. */
> >>>    if (is_src_route) {
> >>>        dir = "src";
> >>> -        *priority = plen * 2;
> >>> +        ofs = 0;
> >>>    } else {
> >>>        dir = "dst";
> >>> -        *priority = (plen * 2) + 1;
> >>>    }
> >>>
> >>> +    *priority = (plen * ROUTE_PRIO_OFFSET_MULTIPLIER) + ofs;
> >>> +
> >>>    if (op_inport) {
> >>>        ds_put_format(match, "inport == %s && ", op_inport->json_key);
> >>>    }
> >>> @@ -9073,7 +9085,7 @@ add_ecmp_symmetric_reply_flows(struct hmap *lflows,
> >>>                  out_port->lrp_networks.ea_s,
> >>>                  IN6_IS_ADDR_V4MAPPED(&route->prefix) ? "" : "xx",
> >>>                  port_ip, out_port->json_key);
> >>> -    ovn_lflow_add_with_hint(lflows, od, S_ROUTER_IN_IP_ROUTING, 300,
> >>> +    ovn_lflow_add_with_hint(lflows, od, S_ROUTER_IN_IP_ROUTING, 10300,
> >>>                           ds_cstr(&match), ds_cstr(&actions),
> >>>                           &st_route->header_);
> >>>
> >>> @@ -9103,8 +9115,10 @@ build_ecmp_route_flow(struct hmap *lflows, struct ovn_datapath *od,
> >>>    struct ds route_match = DS_EMPTY_INITIALIZER;
> >>>
> >>>    char *prefix_s = build_route_prefix_s(&eg->prefix, eg->plen);
> >>> +    int ofs = !strcmp(eg->origin, ROUTE_ORIGIN_CONNECTED) ?
> >>> +        ROUTE_PRIO_OFFSET_CONNECTED: ROUTE_PRIO_OFFSET_STATIC;
> >>>    build_route_match(NULL, prefix_s, eg->plen, eg->is_src_route, is_ipv4,
> >>> -                      &route_match, &priority);
> >>> +                      &route_match, &priority, ofs);
> >>>    free(prefix_s);
> >>>
> >>>    struct ds actions = DS_EMPTY_INITIALIZER;
> >>> @@ -9180,7 +9194,7 @@ add_route(struct hmap *lflows, struct ovn_datapath *od,
> >>>          const struct ovn_port *op, const char *lrp_addr_s,
> >>>          const char *network_s, int plen, const char *gateway,
> >>>          bool is_src_route, const struct ovsdb_idl_row *stage_hint,
> >>> -          bool is_discard_route)
> >>> +          bool is_discard_route, int ofs)
> >>> {
> >>>    bool is_ipv4 = strchr(network_s, '.') ? true : false;
> >>>    struct ds match = DS_EMPTY_INITIALIZER;
> >>> @@ -9196,7 +9210,7 @@ add_route(struct hmap *lflows, struct ovn_datapath *od,
> >>>        }
> >>>    }
> >>>    build_route_match(op_inport, network_s, plen, is_src_route, is_ipv4,
> >>> -                      &match, &priority);
> >>> +                      &match, &priority, ofs);
> >>>
> >>>    struct ds common_actions = DS_EMPTY_INITIALIZER;
> >>>    struct ds actions = DS_EMPTY_INITIALIZER;
> >>> @@ -9256,10 +9270,15 @@ build_static_route_flow(struct hmap *lflows, struct ovn_datapath *od,
> >>>        }
> >>>    }
> >>>
> >>> +    int ofs = !strcmp(smap_get_def(&route->options, "origin", ""),
> >>> +                      ROUTE_ORIGIN_CONNECTED) ? ROUTE_PRIO_OFFSET_CONNECTED
> >>> +                                              : ROUTE_PRIO_OFFSET_STATIC;
> >>> +
> >>>    char *prefix_s = build_route_prefix_s(&route_->prefix, route_->plen);
> >>>    add_route(lflows, route_->is_discard_route ? od : out_port->od, out_port,
> >>>              lrp_addr_s, prefix_s, route_->plen, route->nexthop,
> >>> -              route_->is_src_route, &route->header_, route_->is_discard_route);
> >>> +              route_->is_src_route, &route->header_, route_->is_discard_route,
> >>> +              ofs);
> >>>
> >>>    free(prefix_s);
> >>> }
> >>> @@ -10672,14 +10691,14 @@ build_ip_routing_flows_for_lrouter_port(
> >>>            add_route(lflows, op->od, op, op->lrp_networks.ipv4_addrs[i].addr_s,
> >>>                      op->lrp_networks.ipv4_addrs[i].network_s,
> >>>                      op->lrp_networks.ipv4_addrs[i].plen, NULL, false,
> >>> -                      &op->nbrp->header_, false);
> >>> +                      &op->nbrp->header_, false, ROUTE_PRIO_OFFSET_CONNECTED);
> >>>        }
> >>>
> >>>        for (int i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) {
> >>>            add_route(lflows, op->od, op, op->lrp_networks.ipv6_addrs[i].addr_s,
> >>>                      op->lrp_networks.ipv6_addrs[i].network_s,
> >>>                      op->lrp_networks.ipv6_addrs[i].plen, NULL, false,
> >>> -                      &op->nbrp->header_, false);
> >>> +                      &op->nbrp->header_, false, ROUTE_PRIO_OFFSET_CONNECTED);
> >>>        }
> >>>    } else if (lsp_is_router(op->nbsp)) {
> >>>        struct ovn_port *peer = ovn_port_get_peer(ports, op);
> >>> @@ -10702,7 +10721,8 @@ build_ip_routing_flows_for_lrouter_port(
> >>>                              peer->lrp_networks.ipv4_addrs[0].addr_s,
> >>>                              laddrs->ipv4_addrs[k].network_s,
> >>>                              laddrs->ipv4_addrs[k].plen, NULL, false,
> >>> -                              &peer->nbrp->header_, false);
> >>> +                              &peer->nbrp->header_, false,
> >>> +                              ROUTE_PRIO_OFFSET_CONNECTED);
> >>>                }
> >>>            }
> >>>        }
> >>> @@ -10773,7 +10793,7 @@ build_mcast_lookup_flows_for_lrouter(
> >>>        /* Drop IPv6 multicast traffic that shouldn't be forwarded,
> >>>         * i.e., router solicitation and router advertisement.
> >>>         */
> >>> -        ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 550,
> >>> +        ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 10550,
> >>>                      "nd_rs || nd_ra", "drop;");
> >>>        if (!od->mcast_info.rtr.relay) {
> >>>            return;
> >>> @@ -10801,7 +10821,7 @@ build_mcast_lookup_flows_for_lrouter(
> >>>            }
> >>>            ds_put_format(actions, "outport = \"%s\"; ip.ttl--; next;",
> >>>                          igmp_group->mcgroup.name);
> >>> -            ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 500,
> >>> +            ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 10500,
> >>>                          ds_cstr(match), ds_cstr(actions));
> >>>        }
> >>>
> >>> @@ -10809,7 +10829,7 @@ build_mcast_lookup_flows_for_lrouter(
> >>>         * ports. Otherwise drop any multicast traffic.
> >>>         */
> >>>        if (od->mcast_info.rtr.flood_static) {
> >>> -            ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 450,
> >>> +            ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 10450,
> >>>                          "ip4.mcast || ip6.mcast",
> >>>                          "clone { "
> >>>                                "outport = \""MC_STATIC"\"; "
> >>> @@ -10817,7 +10837,7 @@ build_mcast_lookup_flows_for_lrouter(
> >>>                                "next; "
> >>>                          "};");
> >>>        } else {
> >>> -            ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 450,
> >>> +            ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, 10450,
> >>>                          "ip4.mcast || ip6.mcast", "drop;");
> >>>        }
> >>>    }
> >>> diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> >>> index fb67395e3..4f3a9d5e3 100644
> >>> --- a/northd/ovn-northd.8.xml
> >>> +++ b/northd/ovn-northd.8.xml
> >>> @@ -2945,12 +2945,12 @@ icmp6 {
> >>>
> >>>    <p>
> >>>      If ECMP routes with symmetric reply are configured in the
> >>> -      <code>OVN_Northbound</code> database for a gateway router, a priority-300
> >>> -      flow is added for each router port on which symmetric replies are
> >>> -      configured. The matching logic for these ports essentially reverses the
> >>> -      configured logic of the ECMP route. So for instance, a route with a
> >>> -      destination routing policy will instead match if the source IP address
> >>> -      matches the static route's prefix. The flow uses the action
> >>> +      <code>OVN_Northbound</code> database for a gateway router, a
> >>> +      priority-10300 flow is added for each router port on which symmetric
> >>> +      replies are configured. The matching logic for these ports essentially
> >>> +      reverses the configured logic of the ECMP route. So for instance, a route
> >>> +      with a destination routing policy will instead match if the source IP
> >>> +      address matches the static route's prefix. The flow uses the action
> >>>      <code>ct_next</code> to send IP packets to the connection tracker for
> >>>      packet de-fragmentation and tracking before sending it to the next table.
> >>>    </p>
> >>> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> >>> index 85b47a18f..3c1a97f73 100644
> >>> --- a/tests/ovn-northd.at
> >>> +++ b/tests/ovn-northd.at
> >>> @@ -5430,7 +5430,7 @@ check ovn-nbctl --wait=sb --ecmp-symmetric-reply lr-route-add lr0 1.0.0.1 192.16
> >>>
> >>> ovn-sbctl dump-flows lr0 > lr0flows
> >>> AT_CHECK([grep -e "lr_in_ip_routing.*select" lr0flows | sed 's/table=../table=??/' | sort], [0], [dnl
> >>> -  table=??(lr_in_ip_routing   ), priority=65   , match=(ip4.dst == 1.0.0.1/32), action=(ip.ttl--; flags.loopback = 1; reg8[[0..15]] = 1; reg8[[16..31]] = select(1, 2);)
> >>> +  table=??(lr_in_ip_routing   ), priority=97   , match=(ip4.dst == 1.0.0.1/32), action=(ip.ttl--; flags.loopback = 1; reg8[[0..15]] = 1; reg8[[16..31]] = select(1, 2);)
> >>> ])
> >>> AT_CHECK([grep -e "lr_in_ip_routing_ecmp" lr0flows | sed 's/192\.168\.0\..0/192.168.0.??/' | sed 's/table=../table=??/' | sort], [0], [dnl
> >>>  table=??(lr_in_ip_routing_ecmp), priority=100  , match=(reg8[[0..15]] == 1 && reg8[[16..31]] == 1), action=(reg0 = 192.168.0.??; reg1 = 192.168.0.1; eth.src = 00:00:20:20:12:13; outport = "lr0-public"; next;)
> >>> @@ -5443,7 +5443,7 @@ check ovn-nbctl --wait=sb --ecmp-symmetric-reply lr-route-add lr0 1.0.0.1 192.16
> >>>
> >>> ovn-sbctl dump-flows lr0 > lr0flows
> >>> AT_CHECK([grep -e "lr_in_ip_routing.*select" lr0flows | sed 's/table=../table=??/' | sort], [0], [dnl
> >>> -  table=??(lr_in_ip_routing   ), priority=65   , match=(ip4.dst == 1.0.0.1/32), action=(ip.ttl--; flags.loopback = 1; reg8[[0..15]] = 1; reg8[[16..31]] = select(1, 2);)
> >>> +  table=??(lr_in_ip_routing   ), priority=97   , match=(ip4.dst == 1.0.0.1/32), action=(ip.ttl--; flags.loopback = 1; reg8[[0..15]] = 1; reg8[[16..31]] = select(1, 2);)
> >>> ])
> >>> AT_CHECK([grep -e "lr_in_ip_routing_ecmp" lr0flows | sed 's/192\.168\.0\..0/192.168.0.??/' | sed 's/table=../table=??/' | sort], [0], [dnl
> >>>  table=??(lr_in_ip_routing_ecmp), priority=100  , match=(reg8[[0..15]] == 1 && reg8[[16..31]] == 1), action=(reg0 = 192.168.0.??; reg1 = 192.168.0.1; eth.src = 00:00:20:20:12:13; outport = "lr0-public"; next;)
> >>> @@ -5458,14 +5458,14 @@ check ovn-nbctl --wait=sb lr-route-add lr0 1.0.0.0/24 192.168.0.10
> >>> ovn-sbctl dump-flows lr0 > lr0flows
> >>>
> >>> AT_CHECK([grep -e "lr_in_ip_routing.*192.168.0.10" lr0flows | sed 's/table=../table=??/' | sort], [0], [dnl
> >>> -  table=??(lr_in_ip_routing   ), priority=49   , match=(ip4.dst == 1.0.0.0/24), action=(ip.ttl--; reg8[[0..15]] = 0; reg0 = 192.168.0.10; reg1 = 192.168.0.1; eth.src = 00:00:20:20:12:13; outport = "lr0-public"; flags.loopback = 1; next;)
> >>> +  table=??(lr_in_ip_routing   ), priority=73   , match=(ip4.dst == 1.0.0.0/24), action=(ip.ttl--; reg8[[0..15]] = 0; reg0 = 192.168.0.10; reg1 = 192.168.0.1; eth.src = 00:00:20:20:12:13; outport = "lr0-public"; flags.loopback = 1; next;)
> >>> ])
> >>>
> >>> check ovn-nbctl --wait=sb lr-route-add lr0 2.0.0.0/24 lr0-public
> >>>
> >>> ovn-sbctl dump-flows lr0 > lr0flows
> >>> AT_CHECK([grep -e "lr_in_ip_routing.*2.0.0.0" lr0flows | sed 's/table=../table=??/' | sort], [0], [dnl
> >>> -  table=??(lr_in_ip_routing   ), priority=49   , match=(ip4.dst == 2.0.0.0/24), action=(ip.ttl--; reg8[[0..15]] = 0; reg0 = ip4.dst; reg1 = 192.168.0.1; eth.src = 00:00:20:20:12:13; outport = "lr0-public"; flags.loopback = 1; next;)
> >>> +  table=??(lr_in_ip_routing   ), priority=73   , match=(ip4.dst == 2.0.0.0/24), action=(ip.ttl--; reg8[[0..15]] = 0; reg0 = ip4.dst; reg1 = 192.168.0.1; eth.src = 00:00:20:20:12:13; outport = "lr0-public"; flags.loopback = 1; next;)
> >>> ])
> >>>
> >>> AT_CLEANUP
> >>> --
> >>> 2.30.0
> >>>
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