From be5b458778abfc6dd3d30c0f520c77186935f9b2 Mon Sep 17 00:00:00 2001 From: Numan Siddique Date: Tue, 19 Nov 2019 17:52:01 +0530 Subject: [PATCH 2/2] Skip IPv6 NS packets in router egress SNAT pipeline When ovn-controller injects IPv6 NS packet to learn the mac, in some setups it is observed that the packet is dropped by ovs-vswitchd. We see below logs 2019-11-18T10:42:17.973Z|00001|ofproto_dpif_upcall(handler6)|INFO|received packet on unassociated datapath port 4294967295 2019-11-18T10:42:18.221Z|00001|ofproto_dpif_upcall(revalidator8)|WARN|Failed to acquire udpif_key corresponding to unexpected flow (Invalid argument): ufid:9ba1081f-a692-4c1c-a79b-d1cf04175f7d Upon further debugging I noticed that, xlate_lookup() fails when there is upcall from kernel datapath because of ct related actions. When ovn-controller injects the packet it sets inport=CONTROLLER. This patch addresses this issue by avoiding the IPv6 NS packets to be sent to conntrack in the router egress pipeline. This should be ideally fixed in ovs-vswitchd. Reported-by: Russell Bryant Signed-off-by: Numan Siddique --- ovn/northd/ovn-northd.8.xml | 9 +++++++++ ovn/northd/ovn-northd.c | 5 +++++ 2 files changed, 14 insertions(+) diff --git a/ovn/northd/ovn-northd.8.xml b/ovn/northd/ovn-northd.8.xml index 0fac02340..8f8fd5c01 100644 --- a/ovn/northd/ovn-northd.8.xml +++ b/ovn/northd/ovn-northd.8.xml @@ -2704,6 +2704,15 @@ nd_ns { changed based on the configuration in the OVN Northbound database.

+
    +
  • + A priority-120 flow to advance the IPv6 Neighbor solicitation packet + to next table to skip SNAT. In the case where ovn-controller injects + an IPv6 Neighbor Solicitation packet (for nd_ns action) + we don't want the packet to go throught conntrack. +
    • +
+

Egress Table 1: SNAT on Gateway Routers

    diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c index bcadcca3d..d94276b1e 100644 --- a/ovn/northd/ovn-northd.c +++ b/ovn/northd/ovn-northd.c @@ -7394,6 +7394,11 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports, ovn_lflow_add(lflows, od, S_ROUTER_OUT_UNDNAT, 0, "1", "next;"); ovn_lflow_add(lflows, od, S_ROUTER_OUT_EGR_LOOP, 0, "1", "next;"); + /* Send the IPv6 NS packets to next table. When ovn-controller + * generates IPv6 NS (for the action - nd_ns{}), the injected + * packet would go through conntrack - which is not required. */ + ovn_lflow_add(lflows, od, S_ROUTER_OUT_SNAT, 120, "nd_ns", "next;"); + /* NAT rules are only valid on Gateway routers and routers with * l3dgw_port (router has a port with "redirect-chassis" * specified). */ -- 2.23.0