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

Odintsov Vladislav VlOdintsov at croc.ru
Thu Nov 18 06:13:37 UTC 2021


+ Han

Regards,
Vladislav Odintsov

On 18 Nov 2021, at 09:10, Vladislav Odintsov <odivlad at gmail.com<mailto:odivlad at gmail.com>> wrote:

Great, thanks.

Hi @Han,

I’d like you to look at the patch series too. Would you have time on it?
If yes, could you redirect me on terms please.

Thanks.

Regards,
Vladislav Odintsov

On 18 Nov 2021, at 00:05, Numan Siddique <numans at ovn.org<mailto:numans at ovn.org>> wrote:

On Wed, Nov 17, 2021 at 3:38 PM Vladislav Odintsov <odivlad at gmail.com<mailto:odivlad at gmail.com> <mailto:odivlad at gmail.com>> wrote:

I’ve submitted a patch [1] with my findings.
Also, if no comments for other my patches from this patch series, I can submit a new version.
Should I?

No comments from my side.  Perhaps you can submit another version.

Numan


1: https://patchwork.ozlabs.org/project/ovn/patch/20211117203545.46142-1-odivlad@gmail.com/ <https://patchwork.ozlabs.org/project/ovn/patch/20211117203545.46142-1-odivlad@gmail.com/>

Regards,
Vladislav Odintsov

On 17 Nov 2021, at 20:57, Numan Siddique <numans at ovn.org<mailto:numans at ovn.org> <mailto:numans at ovn.org>> wrote:

On Wed, Nov 17, 2021 at 9:24 AM Vladislav Odintsov <odivlad at gmail.com<mailto:odivlad at gmail.com> <mailto:odivlad at gmail.com> <mailto:odivlad at gmail.com <mailto: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<mailto: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<mailto: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> <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<mailto: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<http://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<http://ovn-northd.at> b/tests/ovn-northd.at<http://ovn-northd.at>
index 85b47a18f..3c1a97f73 100644
--- a/tests/ovn-northd.at<http://ovn-northd.at>
+++ b/tests/ovn-northd.at<http://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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