[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 02:17:02 UTC 2021
On Sat, Nov 13, 2021 at 4:44 AM Vladislav Odintsov <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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