[ovs-dev] [PATCH v3 ovn] manage ARP process locally in a DVR scenario
Numan Siddique
numans at ovn.org
Mon Mar 2 12:59:29 UTC 2020
On Mon, Mar 2, 2020 at 3:08 PM Lorenzo Bianconi
<lorenzo.bianconi at redhat.com> wrote:
>
> OVN currently performs L2 address resolution and IP buffering on the
> gw node. If the system relies on FIPs, OVN will re-inject the buffered
> IP packets on the gw node, while following packets will go though
> the localnet port on the compute node resulting in a ToR switch
> misconfiguration. This patch addresses the issue managing ARP
> and IP buffering locally if FIPs are configured on the node
>
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
Thanks Lorenzo. I applied this patch to master and branch-20.03 (as
it's a pretty serious bug
and we need the fix)
I applied by adding the below test case and some modifications to
ovn-northd.8.xml. The patch modified
the priority of some of the existing logical flows. I updated the
documentation accordingly.
*************
diff --git a/tests/ovn.at b/tests/ovn.at
index 3f0fb9c18..a04f22c4c 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -9503,6 +9503,20 @@ AT_CHECK([as hv3 ovs-vsctl set Open_vSwitch .
external-ids:ovn-bridge-mappings=p
OVS_WAIT_UNTIL([test 1 = `as hv3 ovs-vsctl show | \
grep "Port patch-br-int-to-ln_port" | wc -l`])
+AT_CHECK([test 1 = `ovn-sbctl dump-flows lr0 | grep lr_in_ip_routing | \
+grep "ip4.src == 10.0.0.3 && is_chassis_resident(\"foo1\")" -c`])
+AT_CHECK([test 1 = `ovn-sbctl dump-flows lr0 | grep lr_in_ip_routing | \
+grep "ip4.src == 10.0.0.4 && is_chassis_resident(\"foo2\")" -c`])
+
+key=`ovn-sbctl --bare --columns tunnel_key list datapath_Binding lr0`
+# Check that the OVS flows appear for the dnat_and_snat entries in
+# lr_in_ip_routing table.
+OVS_WAIT_UNTIL([test 1 = `as hv3 ovs-ofctl dump-flows br-int table=17 | \
+grep "priority=400,ip,metadata=0x$key,nw_src=10.0.0.3" -c`])
+
+OVS_WAIT_UNTIL([test 1 = `as hv3 ovs-ofctl dump-flows br-int table=17 | \
+grep "priority=400,ip,metadata=0x$key,nw_src=10.0.0.4" -c`])
+
# Re-add nat-addresses option
ovn-nbctl lsp-set-options lrp0-rp router-port=lrp0 nat-addresses="router"
**************
Thanks
Numan
> ---
> Changes since v2:
> - fix memory leak in add_distributed_routes
> - move check on logical router port before running add_distributed_routes
>
> Changes since v1:
> - add comments
> - cosmetics
> ---
> northd/ovn-northd.8.xml | 31 ++++++++++++++++++++++++
> northd/ovn-northd.c | 53 ++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 83 insertions(+), 1 deletion(-)
>
> diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> index a27dfa951..23b385377 100644
> --- a/northd/ovn-northd.8.xml
> +++ b/northd/ovn-northd.8.xml
> @@ -2405,6 +2405,37 @@ output;
> </p>
> </li>
>
> + <li>
> + <p>
> + For distributed logical routers where one of the logical router ports
> + specifies a <code>redirect-chassis</code>, a priority-400 logical
> + flow for each <code>dnat_and_snat</code> NAT rules configured.
> + These flows will allow to properly forward traffic to the external
> + connections if available and avoid sending it through the tunnel.
> + Assuming the following NAT rule has been configured:
> + </p>
> +
> + <pre>
> +external_ip = <var>A</var>;
> +external_mac = <var>B</var>;
> +logical_ip = <var>C</var>;
> + </pre>
> +
> + <p>
> + the following action will be applied:
> + </p>
> +
> + <pre>
> +ip.ttl--;
> +reg0 = <var>ip.dst</var>;
> +reg1 = <var>A</var>;
> +eth.src = <var>B</var>;
> +outport = <var>router-port</var>;
> +next;
> + </pre>
> +
> + </li>
> +
> <li>
> <p>
> IPv4 routing table. For each route to IPv4 network <var>N</var> with
> diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> index 3a24d3c4f..0d43322cf 100644
> --- a/northd/ovn-northd.c
> +++ b/northd/ovn-northd.c
> @@ -6972,6 +6972,8 @@ build_routing_policy_flow(struct hmap *lflows, struct ovn_datapath *od,
> ds_destroy(&actions);
> }
>
> +/* default logical flow prioriry for distributed routes */
> +#define DROUTE_PRIO 400
> struct parsed_route {
> struct ovs_list list_node;
> struct v46_ip prefix;
> @@ -7359,6 +7361,40 @@ build_ecmp_route_flow(struct hmap *lflows, struct ovn_datapath *od,
> ds_destroy(&actions);
> }
>
> +static void
> +add_distributed_routes(struct hmap *lflows, struct ovn_datapath *od)
> +{
> + struct ds actions = DS_EMPTY_INITIALIZER;
> + struct ds match = DS_EMPTY_INITIALIZER;
> +
> + for (size_t i = 0; i < od->nbr->n_nat; i++) {
> + const struct nbrec_nat *nat = od->nbr->nat[i];
> +
> + if (strcmp(nat->type, "dnat_and_snat") ||
> + !nat->external_mac) {
> + continue;
> + }
> +
> + bool is_ipv4 = strchr(nat->logical_ip, '.') ? true : false;
> + ds_put_format(&match, "ip%s.src == %s && is_chassis_resident(\"%s\")",
> + is_ipv4 ? "4" : "6", nat->logical_ip,
> + nat->logical_port);
> + char *prefix = is_ipv4 ? "" : "xx";
> + ds_put_format(&actions, "outport = %s; eth.src = %s; "
> + "%sreg0 = ip%s.dst; %sreg1 = %s; next;",
> + od->l3dgw_port->json_key, nat->external_mac,
> + prefix, is_ipv4 ? "4" : "6",
> + prefix, nat->external_ip);
> + ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, DROUTE_PRIO,
> + ds_cstr(&match), ds_cstr(&actions));
> + ds_clear(&match);
> + ds_clear(&actions);
> + }
> +
> + ds_destroy(&actions);
> + ds_destroy(&match);
> +}
> +
> static void
> add_route(struct hmap *lflows, const struct ovn_port *op,
> const char *lrp_addr_s, const char *network_s, int plen,
> @@ -7380,6 +7416,12 @@ add_route(struct hmap *lflows, const struct ovn_port *op,
> }
> build_route_match(op_inport, network_s, plen, is_src_route, is_ipv4,
> &match, &priority);
> + /* traffic for internal IPs of logical switch ports must be sent to
> + * the gw controller through the overlay tunnels
> + */
> + if (op->nbrp && !op->nbrp->n_gateway_chassis) {
> + priority += DROUTE_PRIO;
> + }
>
> struct ds actions = DS_EMPTY_INITIALIZER;
> ds_put_format(&actions, "ip.ttl--; "REG_ECMP_GROUP_ID" = 0; %sreg0 = ",
> @@ -8948,7 +8990,7 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
> nat->logical_ip,
> od->l3dgw_port->json_key);
> ovn_lflow_add_with_hint(lflows, od, S_ROUTER_IN_GW_REDIRECT,
> - 100, ds_cstr(&match), "next;",
> + 200, ds_cstr(&match), "next;",
> &nat->header_);
> }
>
> @@ -9229,6 +9271,15 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
> ovn_lflow_add(lflows, od, S_ROUTER_IN_ND_RA_RESPONSE, 0, "1", "next;");
> }
>
> + /* Logical router ingress table IP_ROUTING - IP routing for distributed
> + * logical router
> + */
> + HMAP_FOR_EACH (od, key_node, datapaths) {
> + if (od->nbr && od->l3dgw_port) {
> + add_distributed_routes(lflows, od);
> + }
> + }
> +
> /* Logical router ingress table IP_ROUTING & IP_ROUTING_ECMP: IP Routing.
> *
> * A packet that arrives at this table is an IP packet that should be
> --
> 2.24.1
>
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