On Thu, Feb 6, 2025 at 12:24 AM Lorenzo Bianconi
<[email protected]> wrote:
>
> > For each vrf we use we open a netlink watcher.
> > This allows us to reconcile on changed route entries from outside
> > routing agents.
> >
> > Signed-off-by: Felix Huettner <[email protected]>
>
> Hi Felix,
>
> the patch seems fine to me.
> Acked-by: Lorenzo Bianconi <[email protected]>
>
> Regards,
> Lorenzo

Thanks for the patch!

I have a variable name change request and a request for a TODO (if you
agree) below.

In the interest of time we can keep the current implementation, as I
don't expect anyone to add thousands of routers with dynamic-routing
on them, it will rather be aggregated in a few. However, I don't
understand why you need a watcher per VRF. Why not filter and route
the changes to their appropriate destinations in the callback function
that you provide? Please add this as a TODO if you agree.

With those addressed:
Acked-by: Frode Nordahl <[email protected]>

>
> > ---
> > v5->v6:
> >   * addressed review comments
> >
> >  controller/automake.mk               |   7 +-
> >  controller/ovn-controller.c          |  51 ++++++-
> >  controller/route-exchange.c          |   6 +-
> >  controller/route-exchange.h          |   3 +
> >  controller/route-table-notify-stub.c |  56 ++++++++
> >  controller/route-table-notify.c      | 198 +++++++++++++++++++++++++++
> >  controller/route-table-notify.h      |  44 ++++++
> >  tests/system-ovn.at                  |   4 -
> >  8 files changed, 360 insertions(+), 9 deletions(-)
> >  create mode 100644 controller/route-table-notify-stub.c
> >  create mode 100644 controller/route-table-notify.c
> >  create mode 100644 controller/route-table-notify.h
> >
> > diff --git a/controller/automake.mk b/controller/automake.mk
> > index fa3083d2d..c789c313c 100644
> > --- a/controller/automake.mk
> > +++ b/controller/automake.mk
> > @@ -55,6 +55,7 @@ controller_ovn_controller_SOURCES = \
> >       controller/ecmp-next-hop-monitor.h \
> >       controller/ecmp-next-hop-monitor.c \
> >       controller/route-exchange.h \
> > +     controller/route-table-notify.h \
> >       controller/route.h \
> >       controller/route.c
> >
> > @@ -62,10 +63,12 @@ if HAVE_NETLINK
> >  controller_ovn_controller_SOURCES += \
> >       controller/route-exchange-netlink.h \
> >       controller/route-exchange-netlink.c \
> > -     controller/route-exchange.c
> > +     controller/route-exchange.c \
> > +     controller/route-table-notify.c
> >  else
> >  controller_ovn_controller_SOURCES += \
> > -     controller/route-exchange-stub.c
> > +     controller/route-exchange-stub.c \
> > +     controller/route-table-notify-stub.c
> >  endif
> >
> >  controller_ovn_controller_LDADD = lib/libovn.la 
> > $(OVS_LIBDIR)/libopenvswitch.la
> > diff --git a/controller/ovn-controller.c b/controller/ovn-controller.c
> > index 5d54fc04d..e819733e9 100644
> > --- a/controller/ovn-controller.c
> > +++ b/controller/ovn-controller.c
> > @@ -90,6 +90,7 @@
> >  #include "ovn-dns.h"
> >  #include "route.h"
> >  #include "route-exchange.h"
> > +#include "route-table-notify.h"
> >
> >  VLOG_DEFINE_THIS_MODULE(main);
> >
> > @@ -5205,10 +5206,16 @@ en_route_exchange_run(struct engine_node *node, 
> > void *data)
> >          .sbrec_port_binding_by_name = sbrec_port_binding_by_name,
> >          .announce_routes = &route_data->announce_routes,
> >      };
> > -    struct route_exchange_ctx_out r_ctx_out = {
> > -    };
> > +    struct route_exchange_ctx_out r_ctx_out = {};
> > +
> > +    hmap_init(&r_ctx_out.route_table_watches);
> >
> >      route_exchange_run(&r_ctx_in, &r_ctx_out);
> > +    route_table_notify_update_watches(&r_ctx_out.route_table_watches);
> > +
> > +    route_table_watch_request_cleanup(&r_ctx_out.route_table_watches);
> > +    hmap_destroy(&r_ctx_out.route_table_watches);
> > +
> >      engine_set_node_state(node, EN_UPDATED);
> >  }
> >
> > @@ -5226,6 +5233,38 @@ static void
> >  en_route_exchange_cleanup(void *data OVS_UNUSED)
> >  {}
> >
> > +struct ed_type_route_table_notify {
> > +    /* For incremental processing this could be tracked per datapath in
> > +     * the future. */
> > +    bool changed;
> > +};
> > +
> > +static void
> > +en_route_table_notify_run(struct engine_node *node, void *data)
> > +{
> > +    struct ed_type_route_table_notify *rtn = data;
> > +    if (rtn->changed) {
> > +        engine_set_node_state(node, EN_UPDATED);
> > +    } else {
> > +        engine_set_node_state(node, EN_UNCHANGED);
> > +    }
> > +    rtn->changed = false;
> > +}
> > +
> > +
> > +static void *
> > +en_route_table_notify_init(struct engine_node *node OVS_UNUSED,
> > +                       struct engine_arg *arg OVS_UNUSED)
> > +{
> > +    struct ed_type_route_table_notify *rtn = xzalloc(sizeof *rtn);
> > +    rtn->changed = true;
> > +    return rtn;
> > +}
> > +
> > +static void
> > +en_route_table_notify_cleanup(void *data OVS_UNUSED)
> > +{}
> > +
> >  /* Returns false if the northd internal version stored in SB_Global
> >   * and ovn-controller internal version don't match.
> >   */
> > @@ -5525,6 +5564,7 @@ main(int argc, char *argv[])
> >      ENGINE_NODE(bfd_chassis, "bfd_chassis");
> >      ENGINE_NODE(dns_cache, "dns_cache");
> >      ENGINE_NODE(route, "route");
> > +    ENGINE_NODE(route_table_notify, "route_table_notify");
> >      ENGINE_NODE(route_exchange, "route_exchange");
> >
> >  #define SB_NODE(NAME, NAME_STR) ENGINE_NODE_SB(NAME, NAME_STR);
> > @@ -5562,6 +5602,7 @@ main(int argc, char *argv[])
> >                       engine_noop_handler);
> >      engine_add_input(&en_route_exchange, &en_sb_port_binding,
> >                       engine_noop_handler);
> > +    engine_add_input(&en_route_exchange, &en_route_table_notify, NULL);
> >
> >      engine_add_input(&en_addr_sets, &en_sb_address_set,
> >                       addr_sets_sb_address_set_handler);
> > @@ -6080,6 +6121,10 @@ main(int argc, char *argv[])
> >                                 &transport_zones,
> >                                 bridge_table);
> >
> > +                    struct ed_type_route_table_notify *rtn =
> > +                        engine_get_internal_data(&en_route_table_notify);
> > +                    rtn->changed = route_table_notify_run();
> > +
> >                      stopwatch_start(CONTROLLER_LOOP_STOPWATCH_NAME,
> >                                      time_msec());
> >
> > @@ -6362,6 +6407,7 @@ main(int argc, char *argv[])
> >              }
> >
> >              binding_wait();
> > +            route_table_notify_wait();
> >          }
> >
> >          unixctl_server_run(unixctl);
> > @@ -6516,6 +6562,7 @@ loop_done:
> >      ovsrcu_exit();
> >      dns_resolve_destroy();
> >      route_exchange_destroy();
> > +    route_table_notify_destroy();
> >
> >      exit(retval);
> >  }
> > diff --git a/controller/route-exchange.c b/controller/route-exchange.c
> > index a1976234b..89d07eeb7 100644
> > --- a/controller/route-exchange.c
> > +++ b/controller/route-exchange.c
> > @@ -29,6 +29,7 @@
> >  #include "ha-chassis.h"
> >  #include "local_data.h"
> >  #include "route.h"
> > +#include "route-table-notify.h"
> >  #include "route-exchange.h"
> >  #include "route-exchange-netlink.h"
> >
> > @@ -167,7 +168,7 @@ sb_sync_learned_routes(const struct ovs_list 
> > *learned_routes,
> >
> >  void
> >  route_exchange_run(struct route_exchange_ctx_in *r_ctx_in,
> > -                   struct route_exchange_ctx_out *r_ctx_out OVS_UNUSED)
> > +                   struct route_exchange_ctx_out *r_ctx_out)
> >  {
> >      struct sset old_maintained_vrfs = 
> > SSET_INITIALIZER(&old_maintained_vrfs);
> >      sset_swap(&_maintained_vrfs, &old_maintained_vrfs);
> > @@ -209,6 +210,9 @@ route_exchange_run(struct route_exchange_ctx_in 
> > *r_ctx_in,
> >                                 r_ctx_in->sbrec_port_binding_by_name,
> >                                 r_ctx_in->sbrec_learned_route_by_datapath);
> >
> > +        route_table_add_watch_request(
> > +            &r_ctx_out->route_table_watches, table_id);
> > +
> >          re_nl_learned_routes_destroy(&received_routes);
> >      }
> >
> > diff --git a/controller/route-exchange.h b/controller/route-exchange.h
> > index 66d8f3945..1e1a09da3 100644
> > --- a/controller/route-exchange.h
> > +++ b/controller/route-exchange.h
> > @@ -18,6 +18,8 @@
> >  #ifndef ROUTE_EXCHANGE_H
> >  #define ROUTE_EXCHANGE_H 1
> >
> > +#include "openvswitch/hmap.h"
> > +
> >  struct route_exchange_ctx_in {
> >      struct ovsdb_idl_txn *ovnsb_idl_txn;
> >      struct ovsdb_idl_index *sbrec_port_binding_by_name;
> > @@ -27,6 +29,7 @@ struct route_exchange_ctx_in {
> >  };
> >
> >  struct route_exchange_ctx_out {
> > +    struct hmap route_table_watches;
> >  };
> >
> >  void route_exchange_run(struct route_exchange_ctx_in *,
> > diff --git a/controller/route-table-notify-stub.c 
> > b/controller/route-table-notify-stub.c
> > new file mode 100644
> > index 000000000..f58897f03
> > --- /dev/null
> > +++ b/controller/route-table-notify-stub.c
> > @@ -0,0 +1,56 @@
> > +/*
> > + * Copyright (c) 2025, STACKIT GmbH & Co. KG
> > + *
> > + * Licensed under the Apache License, Version 2.0 (the "License");
> > + * you may not use this file except in compliance with the License.
> > + * You may obtain a copy of the License at:
> > + *
> > + *     http://www.apache.org/licenses/LICENSE-2.0
> > + *
> > + * Unless required by applicable law or agreed to in writing, software
> > + * distributed under the License is distributed on an "AS IS" BASIS,
> > + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> > + * See the License for the specific language governing permissions and
> > + * limitations under the License.
> > + */
> > +
> > +#include <config.h>
> > +
> > +#include <stdbool.h>
> > +
> > +#include "openvswitch/compiler.h"
> > +#include "route-table-notify.h"
> > +
> > +bool
> > +route_table_notify_run(void)
> > +{
> > +    return false;
> > +}
> > +
> > +void
> > +route_table_notify_wait(void)
> > +{
> > +}
> > +
> > +void
> > +route_table_add_watch_request(struct hmap *route_table_watches OVS_UNUSED,
> > +                              uint32_t table_id OVS_UNUSED)
> > +{
> > +}
> > +
> > +void
> > +route_table_watch_request_cleanup(struct hmap *route_table_watches 
> > OVS_UNUSED)
> > +{
> > +}
> > +
> > +void
> > +route_table_notify_update_watches(
> > +    const struct hmap *route_table_watches OVS_UNUSED)
> > +{
> > +}
> > +
> > +void
> > +route_table_notify_destroy(void)
> > +{
> > +}
> > +
> > diff --git a/controller/route-table-notify.c 
> > b/controller/route-table-notify.c
> > new file mode 100644
> > index 000000000..b79f50eba
> > --- /dev/null
> > +++ b/controller/route-table-notify.c
> > @@ -0,0 +1,198 @@
> > +/*
> > + * Copyright (c) 2025, STACKIT GmbH & Co. KG
> > + *
> > + * Licensed under the Apache License, Version 2.0 (the "License");
> > + * you may not use this file except in compliance with the License.
> > + * You may obtain a copy of the License at:
> > + *
> > + *     http://www.apache.org/licenses/LICENSE-2.0
> > + *
> > + * Unless required by applicable law or agreed to in writing, software
> > + * distributed under the License is distributed on an "AS IS" BASIS,
> > + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> > + * See the License for the specific language governing permissions and
> > + * limitations under the License.
> > + */
> > +
> > +#include <config.h>
> > +
> > +#include <net/if.h>
> > +#include <linux/rtnetlink.h>
> > +
> > +#include "netlink-notifier.h"
> > +#include "openvswitch/vlog.h"
> > +
> > +#include "binding.h"
> > +#include "hash.h"
> > +#include "hmapx.h"
> > +#include "route-table.h"
> > +#include "route.h"
> > +#include "route-table-notify.h"
> > +#include "route-exchange-netlink.h"
> > +
> > +VLOG_DEFINE_THIS_MODULE(route_table_notify);
> > +
> > +struct route_table_watch_request {
> > +    struct hmap_node node;
> > +    uint32_t table_id;
> > +};
> > +
> > +struct route_table_watch_entry {
> > +    struct hmap_node node;
> > +    uint32_t table_id;
> > +    struct nln *nln;
> > +    struct nln_notifier *route_notifier;
> > +    struct nln_notifier *route6_notifier;
> > +};
> > +
> > +static struct hmap watches = HMAP_INITIALIZER(&watches);
> > +static bool any_route_table_changed;
> > +static struct route_table_msg rtmsg;

nit: As highlighted in
https://github.com/openvswitch/ovs/commit/910bc81e66ba98487469efb95997788d91c2853f,
the above variable name can be very confusing. Would you consider a
different name for it?

--
Frode Nordahl

> > +
> > +static uint32_t
> > +route_table_notify_hash_watch(uint32_t table_id)
> > +{
> > +    return hash_add(0, table_id);
> > +}
> > +
> > +void
> > +route_table_add_watch_request(struct hmap *route_table_watches,
> > +                              uint32_t table_id)
> > +{
> > +    struct route_table_watch_request *wr = xzalloc(sizeof *wr);
> > +    wr->table_id = table_id;
> > +    hmap_insert(route_table_watches, &wr->node,
> > +                route_table_notify_hash_watch(wr->table_id));
> > +}
> > +
> > +void
> > +route_table_watch_request_cleanup(struct hmap *route_table_watches)
> > +{
> > +    struct route_table_watch_request *wr;
> > +    HMAP_FOR_EACH_POP (wr, node, route_table_watches) {
> > +        free(wr);
> > +    }
> > +}
> > +
> > +static struct route_table_watch_entry *
> > +find_watch_entry(uint32_t table_id)
> > +{
> > +    struct route_table_watch_entry *we;
> > +    uint32_t hash = route_table_notify_hash_watch(table_id);
> > +    HMAP_FOR_EACH_WITH_HASH (we, node, hash, &watches) {
> > +        if (table_id == we->table_id) {
> > +            return we;
> > +        }
> > +    }
> > +    return NULL;
> > +}
> > +
> > +static void
> > +route_table_change(const void *change_, void *aux OVS_UNUSED)
> > +{
> > +    const struct route_table_msg *change = change_;
> > +    if (change && change->rd.rtm_protocol != RTPROT_OVN) {
> > +        if (find_watch_entry(change->rd.rta_table_id)) {
> > +            any_route_table_changed = true;
> > +        }
> > +    }
> > +}
> > +
> > +static void
> > +add_watch_entry(uint32_t table_id)
> > +{
> > +    struct route_table_watch_entry *we;
> > +    uint32_t hash = route_table_notify_hash_watch(table_id);
> > +    we = xzalloc(sizeof *we);
> > +    we->table_id = table_id;
> > +    VLOG_INFO("Registering new route table watcher for table %d.",
> > +             table_id);
> > +    we->nln = nln_create(NETLINK_ROUTE, route_table_parse, &rtmsg);
> > +
> > +    we->route_notifier =
> > +        nln_notifier_create(we->nln, RTNLGRP_IPV4_ROUTE,
> > +                            route_table_change, NULL);
> > +    if (!we->route_notifier) {
> > +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 1);
> > +        VLOG_WARN_RL(&rl, "Failed to create ipv4 route table watcher for "
> > +                  "table %d. We will miss routing table updates.", 
> > table_id);
> > +    }
> > +
> > +    we->route6_notifier =
> > +        nln_notifier_create(we->nln, RTNLGRP_IPV6_ROUTE,
> > +                            route_table_change, NULL);
> > +    if (!we->route6_notifier) {
> > +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 1);
> > +        VLOG_WARN_RL(&rl, "Failed to create ipv6 route table watcher for "
> > +                  "table %d. We will miss routing table updates.", 
> > table_id);
> > +    }
> > +
> > +    hmap_insert(&watches, &we->node, hash);
> > +}
> > +
> > +static void
> > +remove_watch_entry(struct route_table_watch_entry *we)
> > +{
> > +    hmap_remove(&watches, &we->node);
> > +    VLOG_INFO("Removing route table watcher for table %d.", we->table_id);
> > +    nln_notifier_destroy(we->route_notifier);
> > +    nln_notifier_destroy(we->route6_notifier);
> > +    nln_destroy(we->nln);
> > +    free(we);
> > +}
> > +
> > +bool
> > +route_table_notify_run(void)
> > +{
> > +    any_route_table_changed = false;
> > +
> > +    struct route_table_watch_entry *we;
> > +    HMAP_FOR_EACH (we, node, &watches) {
> > +        nln_run(we->nln);
> > +    }
> > +
> > +    return any_route_table_changed;
> > +}
> > +
> > +void
> > +route_table_notify_wait(void)
> > +{
> > +    struct route_table_watch_entry *we;
> > +    HMAP_FOR_EACH (we, node, &watches) {
> > +        nln_wait(we->nln);
> > +    }
> > +}
> > +
> > +void
> > +route_table_notify_update_watches(const struct hmap *route_table_watches)
> > +{
> > +    struct hmapx sync_watches = HMAPX_INITIALIZER(&sync_watches);
> > +    struct route_table_watch_entry *we;
> > +    HMAP_FOR_EACH (we, node, &watches) {
> > +        hmapx_add(&sync_watches, we);
> > +    }
> > +
> > +    struct route_table_watch_request *wr;
> > +    HMAP_FOR_EACH (wr, node, route_table_watches) {
> > +        we = find_watch_entry(wr->table_id);
> > +        if (we) {
> > +            hmapx_find_and_delete(&sync_watches, we);
> > +        } else {
> > +            add_watch_entry(wr->table_id);
> > +        }
> > +    }
> > +
> > +    struct hmapx_node *node;
> > +    HMAPX_FOR_EACH (node, &sync_watches) {
> > +        remove_watch_entry(node->data);
> > +    }
> > +}
> > +
> > +void
> > +route_table_notify_destroy(void)
> > +{
> > +    struct route_table_watch_entry *we;
> > +    HMAP_FOR_EACH_SAFE (we, node, &watches) {
> > +        remove_watch_entry(we);
> > +    }
> > +}
> > diff --git a/controller/route-table-notify.h 
> > b/controller/route-table-notify.h
> > new file mode 100644
> > index 000000000..a2bc05a49
> > --- /dev/null
> > +++ b/controller/route-table-notify.h
> > @@ -0,0 +1,44 @@
> > +/*
> > + * Copyright (c) 2025, STACKIT GmbH & Co. KG
> > + *
> > + * Licensed under the Apache License, Version 2.0 (the "License");
> > + * you may not use this file except in compliance with the License.
> > + * You may obtain a copy of the License at:
> > + *
> > + *     http://www.apache.org/licenses/LICENSE-2.0
> > + *
> > + * Unless required by applicable law or agreed to in writing, software
> > + * distributed under the License is distributed on an "AS IS" BASIS,
> > + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> > + * See the License for the specific language governing permissions and
> > + * limitations under the License.
> > + */
> > +
> > +#ifndef ROUTE_TABLE_NOTIFY_H
> > +#define ROUTE_TABLE_NOTIFY_H 1
> > +
> > +#include <stdbool.h>
> > +#include "openvswitch/hmap.h"
> > +
> > +/* Returns true if any route table has changed enough that we need
> > + * to learn new routes. */
> > +bool route_table_notify_run(void);
> > +void route_table_notify_wait(void);
> > +
> > +/* Add a watch request to the hmap. The hmap should later be passed to
> > + * route_table_notify_update_watches*/
> > +void route_table_add_watch_request(struct hmap *route_table_watches,
> > +                                   uint32_t table_id);
> > +
> > +/* Cleanup all watch request in the provided hmap that where added using
> > + * route_table_add_watch_request. */
> > +void route_table_watch_request_cleanup(struct hmap *route_table_watches);
> > +
> > +/* Updates the list of route table watches that are currently active.
> > + * hmap should contain struct route_table_watch_request */
> > +void route_table_notify_update_watches(const struct hmap 
> > *route_table_watches);
> > +
> > +/* Cleans up all route table watches. */
> > +void route_table_notify_destroy(void);
> > +
> > +#endif /* ROUTE_TABLE_NOTIFY_H */
> > diff --git a/tests/system-ovn.at b/tests/system-ovn.at
> > index a13ee4bbf..8b3238a96 100644
> > --- a/tests/system-ovn.at
> > +++ b/tests/system-ovn.at
> > @@ -15677,8 +15677,6 @@ blackhole 198.51.100.0/24 proto 84 metric 1000])
> >  # Now we test route learning.
> >  check_row_count Learned_Route 0
> >  check ip route add 233.252.0.0/24 via 192.168.10.10 dev lo onlink vrf 
> > ovnvrf1337
> > -# For now we trigger a recompute as route watching is not yet implemented.
> > -check ovn-appctl -t ovn-controller inc-engine/recompute
> >  check ovn-nbctl --wait=hv sync
> >  check_row_count Learned_Route 1
> >  lp=$(fetch_column port_binding _uuid logical_port=internet-phys)
> > @@ -15925,8 +15923,6 @@ blackhole 198.51.100.0/24 proto 84 metric 1000])
> >  # Now we test route learning.
> >  check_row_count Learned_Route 0
> >  check ip route add 233.252.0.0/24 via 192.168.10.10 dev lo onlink vrf 
> > ovnvrf1337
> > -# For now we trigger a recompute as route watching is not yet implemented.
> > -check ovn-appctl -t ovn-controller inc-engine/recompute
> >  check ovn-nbctl --wait=hv sync
> >  check_row_count Learned_Route 1
> >  lp=$(fetch_column port_binding _uuid logical_port=internet-phys)
> > --
> > 2.47.1
> >
> >
> > _______________________________________________
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> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >
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