Hallo!!!
We have a problem with flow field "nd_target" at IPv6.
For example.
We have two VM with virtual interfaces vnet0 and vnet1.
At the bridge set fail_mode to "secure":
*# ovs-vsctl list br public-switch | grep fail_mode*
fail_mode : secure
The interface bond0.6 is external interface.
We added only three flows for the test :
*# ovs-ofctl --no-stat dump-flows public-switch --sort=priority*
cookie=0x123575, table=2, priority=1,icmp6,icmp_type=135
actions=output:vnet1
cookie=0x124994, table=2,
priority=108,icmp6,icmp_type=135,nd_target=::2:2::a5
actions=output:vnet0
cookie=0x10005, priority=10005,icmp6,in_port="bond0.6",icmp_type=135
actions=resubmit(,2)
So, all ICMP6 traffic with type 135 going on bond0.6 resubmit to table 2
and the if nd_target field equals to IPv6 address ::2:2::a5 the
traffic send to vnet0 (VM1 have IPv6 ::2:2::a5). All other traffic
should go to vnet1 (VM2).
We start tcpdump on both VMs by command:
*# tcpdump -e -nn -i eth0 "icmp6 && ! ( ip6[40] == 128 || ip6[40] == 129)"*
and start pinging ::2:2::a5 from remote server.
On VM1 on tcpdump output is clear. But on VM2 (with interface vnet1) on tcpdump
output we see the following:
16:52:22.523950 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:23.522694 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:24.467750 xx:xx:xx:01:f0:2b > 33:33:ff:00:00:01, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe01:f02b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has fe80::1, length 32
16:52:24.522639 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:25.523074 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:26.522647 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:27.522594 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:28.538976 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:29.538513 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:30.538550 xx:xx:xx:1b:b3:67 > 33:33:ff:00:00:a5, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe1b:b367 > ff02::1:ff00:a5: ICMP6,
neighbor solicitation, who has ::2:2::a5, length 32
16:52:31.531703 xx:xx:xx:01:e8:b1 > 33:33:ff:00:00:01, ethertype IPv6
(0x86dd), length 86: fe80:::xxff:fe01:e8b1 > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has fe80::1, length 32
As you can see, the ICMP6 traffic with type 135 that have nd_target
field equals
to IPv6 address ::2:2::a5 going to port vnet1 and not to vnet0.
In the same time at the datapath we can see one flow as following:
*# ovs-dpctl --more --names dump-flows filter="icmp6"*
ufid:a545e5e6-39ff-4f5e-a71c-da4c41bbcf22,
recirc_id(0),dp_hash(0/0),skb_priority(0/0),in_port(bond0.6),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),eth(src=00:00:00:00:00:00/00:00:00:00:00:00,dst=00:00:00:00:00:00/00:00:00:00:00:00),eth_type(0x86dd),ipv6(src=::/::,dst=::/::,label=0/0,proto=58,tclass=0/0,hlimit=0/0,frag=no),icmpv6(type=135,code=0/0),nd(target=::/::,sll=00:00:00:00:00:00/00:00:00:00:00:00,tll=00:00:00:00:00:00/00:00:00:00:00:00),
packets:35, bytes:3010, used:0.678s, actions:vnet1
As you can see, field nd_target is set to ::/:: and to ::2:2::a5.
If we start command
*# tcpdump -nn -i bond0.6*
all ICMP6 traffic with type 135 start going to port vnet0 and at the
datapath we see the following flows now:
*# ovs-dpctl --more --names dump-flows filter="icmp6"*
ufid:cee80ab9-4514-447d-8804-d024796cadec,
recirc_id(0),dp_hash(0/0),skb_priority(0/0),in_port(vnet0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),eth(src=00:00:00:00:00:00/00:00:00:00:00:00,dst=00:00:00:00:00:00/00:00:00:00:00:00),eth_type(0x86dd),ipv6(src=::/::,dst=::/::,label=0/0,proto=0/0,tclass=0/0,hlimit=0/0,frag=no),
packets:81, bytes:6966, used:0.340s, actions:drop
ufid:c306b8a3-e023-4077-b5af-fb13ecb21316,
recirc_id(0),dp_hash(0/
