On 8/12/24 06:16, [email protected] wrote:
> From: Numan Siddique <[email protected]>
>
> IPv6 Neigh Solicitation (NS) responder logical flows match on ip6.dst
> field. These flows when translated to datapath flows also match on
> ip6.dst, which means a separate datapath flow per destination IP
> address. This may cause significant performance issues in some
> setups (particularly ovs-dpdk telco deployments).
>
> This patch addresses this issue by matching on eth.mcast6 so that
> datapath flows for normal IPv6 traffic doesn't have to match on
> ip6.dst. IPv6 NS packets are generally multicast. A new logical
> match "nd_ns_mcast" for this purpose.
>
> After this patch, We no longer respond to IPv6 NS unicast packets.
> This behavior now matches the IPv4 ARP responder flows. Note
> that after the commit [1] which was recently added we now only
> respond to IPv4 ARP broadcast packets.
Hi, Numan. Since we sorted out the question I had in the other thread,
here is some code review (I didn't actually review the test).
It would be great if you include some of the rationale for the change
from commit [1] right in here, so it's easier to understand the whole
picture without jumping between commits.
>
> A recent patch [2] from Ilya partially addressed the same datapath
> flow explosion issue by matching on eth.mcast6 for MLD packets.
> With this patch, we now completely address the datapath flow
> explosion issue for IPv6 traffic provided all the logical ports
> of a logical switch are not configured with port security.
>
> [1] - c48ed1736a58 ("Do not reply on unicast arps for IPv4 targets.")
> [2] - 43c34f2e6676 ("logical-fields: Add missing multicast matches for MLD
> and IGMP.")
>
> Reported-at: https://issues.redhat.com/browse/FDP-728
> Reported-by: Mike Pattrick <[email protected]>
> Signed-off-by: Numan Siddique <[email protected]>
> ---
> lib/logical-fields.c | 3 ++
> northd/northd.c | 11 ++--
> tests/ovn-northd.at | 4 +-
> tests/ovn.at | 2 +-
> tests/system-ovn.at | 126 +++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 138 insertions(+), 8 deletions(-)
>
> diff --git a/lib/logical-fields.c b/lib/logical-fields.c
> index 2c9d3c61bf..f1ba1a7ac1 100644
> --- a/lib/logical-fields.c
> +++ b/lib/logical-fields.c
> @@ -293,6 +293,9 @@ ovn_init_symtab(struct shash *symtab)
> "icmp6.type == {135, 136} && icmp6.code == 0 && ip.ttl ==
> 255");
> expr_symtab_add_predicate(symtab, "nd_ns",
> "icmp6.type == 135 && icmp6.code == 0 && ip.ttl == 255");
> + expr_symtab_add_predicate(symtab, "nd_ns_mcast",
> + "eth.mcastv6 && icmp6.type == 135 && icmp6.code == 0 && "
Should this be an 'ip6.mcast' instead? It should be more correct this way.
The expression parser will remove redundancy, if any.
> + "ip.ttl == 255");
> expr_symtab_add_predicate(symtab, "nd_na",
> "icmp6.type == 136 && icmp6.code == 0 && ip.ttl == 255");
> expr_symtab_add_predicate(symtab, "nd_rs",
> diff --git a/northd/northd.c b/northd/northd.c
> index 5ad30d854b..c0cda85e36 100644
> --- a/northd/northd.c
> +++ b/northd/northd.c
> @@ -9638,11 +9638,12 @@ build_lswitch_arp_nd_responder_known_ips(struct
> ovn_port *op,
> * but always respond with the unicast IPv6 address. */
The comment above is talking about matching unicast traffic, which is
no longer the case.
> for (size_t j = 0; j < op->lsp_addrs[i].n_ipv6_addrs; j++) {
> ds_clear(match);
> - ds_put_format(match,
> - "nd_ns && ip6.dst == {%s, %s} && nd.target == %s",
> - op->lsp_addrs[i].ipv6_addrs[j].addr_s,
> - op->lsp_addrs[i].ipv6_addrs[j].sn_addr_s,
> - op->lsp_addrs[i].ipv6_addrs[j].addr_s);
> + ds_put_format(
> + match,
> + "nd_ns_mcast && ip6.dst == {%s, %s} && nd.target == %s",
> + op->lsp_addrs[i].ipv6_addrs[j].addr_s,
The combination of 'nd_ns_mcast' and the unicast 'addr_s' is incorrect, AFAIU.
Should we only match on 'sn_addr_s' here?
> + op->lsp_addrs[i].ipv6_addrs[j].sn_addr_s,
> + op->lsp_addrs[i].ipv6_addrs[j].addr_s);
>
> ds_clear(actions);
> ds_put_format(actions,
> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> index e4c8822656..509cfd2d30 100644
> --- a/tests/ovn-northd.at
> +++ b/tests/ovn-northd.at
> @@ -9490,9 +9490,9 @@ AT_CAPTURE_FILE([S1flows])
> AT_CHECK([grep -e "ls_in_arp_rsp" S1flows | ovn_strip_lflows], [0], [dnl
> table=??(ls_in_arp_rsp ), priority=0 , match=(1), action=(next;)
> table=??(ls_in_arp_rsp ), priority=100 , match=(arp.tpa ==
> 192.168.0.10 && arp.op == 1 && eth.dst == ff:ff:ff:ff:ff:ff && inport ==
> "S1-vm1"), action=(next;)
> - table=??(ls_in_arp_rsp ), priority=100 , match=(nd_ns && ip6.dst ==
> {fd00::10, ff02::1:ff00:10} && nd.target == fd00::10 && inport == "S1-vm1"),
> action=(next;)
> + table=??(ls_in_arp_rsp ), priority=100 , match=(nd_ns_mcast &&
> ip6.dst == {fd00::10, ff02::1:ff00:10} && nd.target == fd00::10 && inport ==
> "S1-vm1"), action=(next;)
> table=??(ls_in_arp_rsp ), priority=50 , match=(arp.tpa ==
> 192.168.0.10 && arp.op == 1 && eth.dst == ff:ff:ff:ff:ff:ff), action=(eth.dst
> = eth.src; eth.src = 50:54:00:00:00:10; arp.op = 2; /* ARP reply */ arp.tha =
> arp.sha; arp.sha = 50:54:00:00:00:10; arp.tpa = arp.spa; arp.spa =
> 192.168.0.10; outport = inport; flags.loopback = 1; output;)
> - table=??(ls_in_arp_rsp ), priority=50 , match=(nd_ns && ip6.dst ==
> {fd00::10, ff02::1:ff00:10} && nd.target == fd00::10), action=(nd_na {
> eth.src = 50:54:00:00:00:10; ip6.src = fd00::10; nd.target = fd00::10; nd.tll
> = 50:54:00:00:00:10; outport = inport; flags.loopback = 1; output; };)
> + table=??(ls_in_arp_rsp ), priority=50 , match=(nd_ns_mcast &&
> ip6.dst == {fd00::10, ff02::1:ff00:10} && nd.target == fd00::10),
> action=(nd_na { eth.src = 50:54:00:00:00:10; ip6.src = fd00::10; nd.target =
> fd00::10; nd.tll = 50:54:00:00:00:10; outport = inport; flags.loopback = 1;
> output; };)
> ])
>
> #Set the disable_arp_nd_rsp option and verify the flow
> diff --git a/tests/ovn.at b/tests/ovn.at
> index a1d689e849..96a89c7d8c 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -14417,7 +14417,7 @@ test_ns_na() {
> local inport=$1 src_mac=$2 dst_mac=$3 src_ip=$4 dst_ip=$5
>
> packet=$(fmt_pkt "
> - Ether(dst='ff:ff:ff:ff:ff:ff', src='${src_mac}') /
> + Ether(dst='33:33:ff:ff:ff:ff', src='${src_mac}') /
> IPv6(src='${src_ip}', dst='ff02::1:ff00:2') /
> ICMPv6ND_NS(tgt='${dst_ip}')
> ")
> diff --git a/tests/system-ovn.at b/tests/system-ovn.at
> index c54b0f3a5f..980472f4e0 100644
> --- a/tests/system-ovn.at
> +++ b/tests/system-ovn.at
> @@ -13750,3 +13750,129 @@ OVS_TRAFFIC_VSWITCHD_STOP(["/.*error receiving.*/d
> /.*terminating with signal 15.*/d"])
> AT_CLEANUP
> ])
> +
> +dnl This test sends IPv6 TCP packets between two lports of the same
> +dnl logical switch and checks that the datapath flows don't match on
> +dnl IPv6 source and destination addresses.
> +OVN_FOR_EACH_NORTHD([
> +AT_SETUP([ovn -- IPv6 switching - datapath flows])
> +AT_KEYWORDS([IPv6])
> +
> +ovn_start
> +OVS_TRAFFIC_VSWITCHD_START()
> +ADD_BR([br-int])
> +
> +dnl Set external-ids in br-int needed for ovn-controller
> +check ovs-vsctl \
> + -- set Open_vSwitch . external-ids:system-id=hv1 \
> + -- set Open_vSwitch .
> external-ids:ovn-remote=unix:$ovs_base/ovn-sb/ovn-sb.sock \
> + -- set Open_vSwitch . external-ids:ovn-encap-type=geneve \
> + -- set Open_vSwitch . external-ids:ovn-encap-ip=169.0.0.1 \
> + -- set bridge br-int fail-mode=secure
> other-config:disable-in-band=true
> +
> +dnl Start ovn-controller
> +start_daemon ovn-controller
> +
> +check ovn-nbctl ls-add sw0
> +
> +check ovn-nbctl lsp-add sw0 vm0
> +check ovn-nbctl lsp-set-addresses vm0 "f0:00:0f:01:02:03 10.0.0.3 1000::3"
> +
> +check ovn-nbctl lsp-add sw0 vm1
> +check ovn-nbctl lsp-set-addresses vm1 "f0:00:0f:01:02:04 10.0.0.4 1000::4"
> +
> +check ovn-nbctl --wait=hv sync
> +
> +ovn-sbctl dump-flows sw0 > /tmp/c.txt
> +
> +ADD_NAMESPACES(vm0)
> +ADD_VETH(vm0, vm0, br-int, "1000::3/64", "f0:00:0f:01:02:03", "1000::1",
> "nodad")
> +
> +ADD_NAMESPACES(vm1)
> +ADD_VETH(vm1, vm1, br-int, "1000::4/64", "f0:00:0f:01:02:04", "1000::1",
> "nodad")
> +
> +dnl Checks the datapath flows and makes sure that there are no matches to
> +dnl IPv6 src or dst fields.
> +check_dp_flows() {
> + ipv6_src_dst_match=$1
> + dnl Dump the flows. Will be helpful while debugging.
> + ovs-appctl dpctl/dump-flows
> +
> + eth_match1="eth(src=f0:00:0f:01:02:03,dst=f0:00:0f:01:02:04)"
> + eth_match2="eth(src=f0:00:0f:01:02:04,dst=f0:00:0f:01:02:03)"
> + ipv6_src_match="ipv6(src="
> + ipv6_dst_match="ipv6(dst="
> +
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match1" -c], [0], [dnl
> +2
> +])
> +
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match2" -c], [0], [dnl
> +2
> +])
> +
> + if [[ "$ipv6_src_dst_match" == "yes" ]]; then
> + dnl Check that the dp flow for
> eth(src=f0:00:0f:01:02:03,dst=f0:00:0f:01:02:04)
> + dnl matches on IPv6 src or dst.
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match1" | grep -e
> "$ipv6_src_match" -e "$ipv6_dst_match" -c], [0], [dnl
> +2
> +])
> +
> + dnl Check that the dp flow for
> eth(src=f0:00:0f:01:02:04,dst=f0:00:0f:01:02:03)
> + dnl matches on IPv6 src or dst.
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match2" | grep -e
> "$ipv6_src_match" -e "$ipv6_dst_match" -c], [0], [dnl
> +2
> +])
> + else
> + dnl Check that the dp flow for
> eth(src=f0:00:0f:01:02:03,dst=f0:00:0f:01:02:04)
> + dnl doesn't match on IPv6 src or dst.
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match1" | grep
> "$ipv6_src_match"], [1], [])
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match1" | grep
> "$ipv6_dst_match"], [1], [])
> +
> + dnl Check that the dp flow for
> eth(src=f0:00:0f:01:02:04,dst=f0:00:0f:01:02:03)
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match2" | grep
> "$ipv6_src_match"], [1], [])
> + AT_CHECK([ovs-appctl dpctl/dump-flows | grep "$eth_match2" | grep
> "$ipv6_dst_match"], [1], [])
> + fi
> +}
> +
> +NS_CHECK_EXEC([vm0], [ping6 -q -c 3 -i 0.3 -w 2 1000::4 | FORMAT_PING], \
> +[0], [dnl
> +3 packets transmitted, 3 received, 0% packet loss, time 0ms
> +])
> +
> +# Start IPv6 TCP server on vm0.
> +NETNS_DAEMONIZE([vm0], [nc -6 -l -k 1000::3 4242], [nc-vm1-1.pid])
> +NS_CHECK_EXEC([vm1], [nc -6 1000::3 4242 -z], [0], [ignore], [ignore])
> +
> +check_dp_flows no
> +
> +# Now configure port security on vm0. dp flows should now match on IPv6
> fields.
> +check ovn-nbctl lsp-set-port-security vm0 "f0:00:0f:01:02:03 10.0.0.3
> 1000::3"
> +check ovn-nbctl --wait=hv sync
> +
> +NS_CHECK_EXEC([vm0], [ping6 -q -c 3 -i 0.3 -w 2 1000::4 | FORMAT_PING], \
> +[0], [dnl
> +3 packets transmitted, 3 received, 0% packet loss, time 0ms
> +])
> +
> +# ovs-appctl dpctl/del-flows || :
Leftover?
> +NS_CHECK_EXEC([vm1], [nc -6 1000::3 4242 -z], [0], [ignore], [ignore])
> +check_dp_flows yes
> +
> +OVS_APP_EXIT_AND_WAIT([ovn-controller])
> +
> +as ovn-sb
> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> +
> +as ovn-nb
> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> +
> +as northd
> +OVS_APP_EXIT_AND_WAIT([ovn-northd])
> +
> +as
> +OVS_TRAFFIC_VSWITCHD_STOP(["/.*error receiving.*/d
> +/failed to query port patch-.*/d
> +/.*terminating with signal 15.*/d"])
> +AT_CLEANUP
> +])
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