{"id":2235282,"url":"http://patchwork.ozlabs.org/api/patches/2235282/?format=json","web_url":"http://patchwork.ozlabs.org/project/ovn/patch/20260509012348.1485266-1-numans@ovn.org/","project":{"id":68,"url":"http://patchwork.ozlabs.org/api/projects/68/?format=json","name":"Open Virtual Network development","link_name":"ovn","list_id":"ovs-dev.openvswitch.org","list_email":"ovs-dev@openvswitch.org","web_url":"http://openvswitch.org/","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260509012348.1485266-1-numans@ovn.org>","list_archive_url":null,"date":"2026-05-09T01:23:48","name":"[ovs-dev] pinctrl: Use correct IPv6 dst for nd_ns action for IPv4 over v6.","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"c43a7a4b98e270e1412e0fb73a708863eb5ebb0a","submitter":{"id":77669,"url":"http://patchwork.ozlabs.org/api/people/77669/?format=json","name":"Numan Siddique","email":"numans@ovn.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/ovn/patch/20260509012348.1485266-1-numans@ovn.org/mbox/","series":[{"id":503473,"url":"http://patchwork.ozlabs.org/api/series/503473/?format=json","web_url":"http://patchwork.ozlabs.org/project/ovn/list/?series=503473","date":"2026-05-09T01:23:48","name":"[ovs-dev] pinctrl: Use correct IPv6 dst for nd_ns action for IPv4 over v6.","version":1,"mbox":"http://patchwork.ozlabs.org/series/503473/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2235282/comments/","check":"warning","checks":"http://patchwork.ozlabs.org/api/patches/2235282/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","dev@openvswitch.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","ovs-dev@lists.linuxfoundation.org"],"Authentication-Results":["legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=openvswitch.org\n (client-ip=140.211.166.136; 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charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"ovs-dev-bounces@openvswitch.org","Sender":"\"dev\" "},"content":"From: Numan Siddique \n\nIf a logical router with dynamic-routing enabled learns a route\nwhose nexthop is an IPv6 address, then ovn-northd adds a logical\nflow in the lr_in_ip_routing stage, but it doesn't add the\npriority-200 logical flow in lr_in_arp_request to resolve the\nmac of the nexthop. The below prioroty-100 logical flow gets invoked\ninstead.\n\ntable=27(lr_in_arp_request ), priority=100 ,\n match=(eth.dst == 00:00:00:00:00:00 && reg9[9] == 0),\n action=(nd_ns { nd.target = xxreg0; output; }; next;)\n\nAnd this doesn't set the correct Solicit IPv6 destination address.\n\nThis patch fixes the issue in pinctrl handler function for nd_ns\naction by using the IPv6 destination address stored in xxreg0.\nThis action assumes that xxreg0 is populated with the proper address.\n\nOther alternative fix is for ovn-northd to add a logical flow\nin lr_in_arp_request just like it adds for static routes.\n\nI think its better to fix it in pinctrl instead.\n\nFound this issue while testing dynamic routing feature.\n\nAssisted-by: Claude Opus 4.7, Claude Code\nSigned-off-by: Numan Siddique \n---\n controller/pinctrl.c | 26 +++++++++++------\n tests/ovn.at | 66 ++++++++++++++++++++++++++++++++++++++++++++\n 2 files changed, 84 insertions(+), 8 deletions(-)","diff":"diff --git a/controller/pinctrl.c b/controller/pinctrl.c\nindex 1a5407183c..452470ff74 100644\n--- a/controller/pinctrl.c\n+++ b/controller/pinctrl.c\n@@ -6534,17 +6534,27 @@ pinctrl_handle_nd_ns(struct rconn *swconn, const struct flow *ip_flow,\n \n /* We might be here without actually currently handling an IPv6 packet.\n * This can happen in the case where we route IPv4 packets over an IPv6\n- * link.\n- * In these cases we have no destination IPv6 address from the packet that\n- * we can reuse. But we receive the actual destination IPv6 address via\n- * userdata anyway, so what we pass to compose_nd_ns is irrelevant.\n- * This is just a hope since we do not parse the userdata. If we land here\n- * for whatever reason without being an IPv6 packet and without userdata we\n- * will send out a wrong packet.\n- */\n+ * link (e.g. RFC 5549 / BGP unnumbered, where an IPv4 destination is\n+ * resolved via an IPv6 link-local nexthop).\n+ *\n+ * In that case we have no destination IPv6 address in the trigger packet\n+ * to reuse. compose_nd_ns() needs a valid destination so it can derive\n+ * the correct solicited-node multicast (ff02::1:ff{addr[13:16]}) for\n+ * eth.dst and ip6.dst -- userdata only sets nd.target on the new packet\n+ * and does not rewrite ip6.dst, so a wrong ipv6_dst here egresses on the\n+ * wire as-is.\n+ *\n+ * The fallback nd_ns logical flow in S_ROUTER_IN_ARP_REQUEST stores the\n+ * actual IPv6 nexthop in xxreg0 (REG_NEXT_HOP_IPV6) before invoking the\n+ * nd_ns action, so for the IPv4-over-IPv6 case read xxreg0 from the\n+ * trigger packet's flow metadata. */\n struct in6_addr ipv6_dst = IN6ADDR_EXACT_INIT;\n if (get_dl_type(ip_flow) == htons(ETH_TYPE_IPV6)) {\n ipv6_dst = ip_flow->ipv6_dst;\n+ } else {\n+ ovs_be128 nexthop_be =\n+ hton128(flow_get_xxreg(&pin->flow_metadata.flow, 0));\n+ memcpy(&ipv6_dst, &nexthop_be, sizeof ipv6_dst);\n }\n compose_nd_ns(&packet, ip_flow->dl_src, &ipv6_src,\n &ipv6_dst);\ndiff --git a/tests/ovn.at b/tests/ovn.at\nindex fbaa63d99c..37e01dc1a9 100644\n--- a/tests/ovn.at\n+++ b/tests/ovn.at\n@@ -46214,3 +46214,69 @@ AT_CHECK([grep -q \"WARN.*dynamic-routing\" hv/ovn-controller.log], [1])\n OVN_CLEANUP([hv])\n AT_CLEANUP\n ])\n+\n+OVN_FOR_EACH_NORTHD([\n+AT_SETUP([IPv4 over v6 Neigh solicitation test])\n+ovn_start\n+\n+net_add n1\n+sim_add hv\n+ovs-vsctl add-br br-phys\n+ovn_attach n1 br-phys 192.168.0.1\n+ovs-vsctl set open . external-ids:ovn-bridge-mappings=phys:br-phys\n+\n+check ovn-nbctl ls-add sw0\n+check ovn-nbctl lsp-add sw0 sw0-port1\n+check ovn-nbctl lsp-set-addresses sw0-port1 \"50:54:00:00:00:01 10.0.0.3\"\n+\n+check ovn-nbctl lr-add lr0\n+check ovn-nbctl lrp-add lr0 lr0-sw0 00:00:00:00:ff:01 10.0.0.1/24 1000::1/64\n+check ovn-nbctl lsp-add-router-port sw0 sw0-lr0 lr0-sw0\n+\n+check ovn-nbctl ls-add public\n+check ovn-nbctl lrp-add lr0 lr0-public 00:00:20:20:12:13\n+check ovn-nbctl lsp-add-router-port public public-lr0 lr0-public\n+\n+# localnet port\n+check ovn-nbctl lsp-add-localnet-port public ln-public phys\n+\n+check ovn-nbctl lrp-set-gateway-chassis lr0-public hv 20\n+check ovn-nbctl lr-nat-add lr0 dnat_and_snat 172.168.0.110 10.0.0.3\n+\n+check ovs-vsctl add-port br-int lsp -- \\\n+ set Interface lsp external_ids:iface-id=lsp\n+\n+ovs-vsctl -- add-port br-int vif1 -- \\\n+ set interface vif1 external-ids:iface-id=sw0-port1 \\\n+ options:tx_pcap=hv/vif1-tx.pcap \\\n+ options:rxq_pcap=hv/vif1-rx.pcap \\\n+ ofport-request=1\n+\n+wait_for_ports_up\n+\n+# Add a learnt route manually\n+dp_uuid=$(fetch_column datapath _uuid external_ids:name=lr0)\n+lrp_uuid=$(fetch_column port_binding _uuid logical_port=lr0-public)\n+\n+ovn-sbctl create learned_route datapath=$dp_uuid logical_port=$lrp_uuid \\\n+ip_prefix=0.0.0.0/0 nexthop='\"fe80::42:ff:fe00:1ff\"'\n+\n+check ovn-nbctl --wait=hv sync\n+\n+# Send an IPv4 packet from sw0-port1 destined to outside\n+packet=$(fmt_pkt \"Ether(dst='00:00:00:00:ff:01', src='50:54:00:00:00:01')/ \\\n+ IP(dst='8.8.8.8', src='10.0.0.3')/ICMP()\")\n+check as hv ovs-appctl netdev-dummy/receive vif1 $packet\n+\n+nd_ns=$(fmt_pkt \"Ether(dst='33:33:ff:00:01:ff', src='00:00:20:20:12:13')/ \\\n+ IPv6(src='fe80::200:20ff:fe20:1213', \\\n+ dst='ff02::1:ff00:1ff')/ICMPv6ND_NS(tgt='fe80::42:ff:fe00:1ff')/\\\n+ ICMPv6NDOptSrcLLAddr(lladdr='00:00:20:20:12:13')\")\n+\n+echo $nd_ns > expected_nd_ns\n+OVN_CHECK_PACKETS_CONTAIN([hv/br-phys_n1-tx.pcap], [expected_nd_ns])\n+\n+OVN_CLEANUP([hv])\n+AT_CLEANUP\n+])\n+\n","prefixes":["ovs-dev"]}