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

Vladislav Odintsov odivlad at gmail.com
Wed Nov 17 10:51:52 UTC 2021


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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