simple openvswitch forward demo not work

Question

What are the details of your problem?

Hi, that is my first time try ovs. i am using Arch Linux, and installed openvswitch.

use sudo ip link add v1 type dummy && sudo ip addr add 10.0.0.1/24 dev v1 && sudo ip link set v1 up created v1, v2 (10.0.0.2/24), v3 (10.0.0.3/24) three virtual network cards.

add v1 v2 v3 to ovs by sudo ovs-vsctl add-port ovsbridge $NETCARDNAME.

add a flow rule by sudo ovs-ofctl add-flow ovsbridge in_port=4,actions=output:5 ( ovs port 4 is v1 netcard, ovs port 5 is v2 netcard). checked by sudo ovs-ofctl show ovsbridge

for now, i use python-scapy send packages to v1 netcard, and i using tcpdump -i INTERFACE_NAME -w tcpdump_output -vnnl catch v1 v2 package nums. v1 received 10 packages, but v2 received 0.

What did you try

# start ovs by systemd

$ sudo ovs-vsctl add-br ovsbridge

$ sudo ovs-vsctl show
7194d04a-66aa-48c2-bfa4-99bbdc6fc4b2
    Bridge ovsbridge
        Port ovsbridge
            Interface ovsbridge
                type: internal

$ ip a # part of
8: ovs-system: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 3e:9a:4c:83:04:43 brd ff:ff:ff:ff:ff:ff
9: ovsbridge: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether 96:35:f1:d2:6b:46 brd ff:ff:ff:ff:ff:ff

$ sudo ip link add v1 type dummy
$ sudo ip addr add 10.0.0.1/24 dev v1
$ sudo ip link set v1 up
# and same to v2 v3

# add them to ovs
$ sudo ovs-vsctl add-port ovsbridge v1

$ sudo ovs-vsctl show
7194d04a-66aa-48c2-bfa4-99bbdc6fc4b2
    Bridge ovsbridge
        Port ovsbridge
            Interface ovsbridge
                type: internal
        Port v3
            Interface v3
        Port v2
            Interface v2
        Port v1
            Interface v1

$ ip a # part of
38: v1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master ovs-system state UNKNOWN group default qlen 1000
    link/ether da:11:b3:77:37:54 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.1/24 scope global v1
       valid_lft forever preferred_lft forever
    inet6 fe80::d811:b3ff:fe77:3754/64 scope link 
       valid_lft forever preferred_lft forever
39: v2: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master ovs-system state UNKNOWN group default qlen 1000
    link/ether ca:06:56:9c:af:6d brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.2/24 scope global v2
       valid_lft forever preferred_lft forever
    inet6 fe80::c806:56ff:fe9c:af6d/64 scope link 
       valid_lft forever preferred_lft forever
40: v3: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master ovs-system state UNKNOWN group default qlen 1000
    link/ether 82:a4:e7:b0:e0:71 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.3/24 scope global v3
       valid_lft forever preferred_lft forever
    inet6 fe80::80a4:e7ff:feb0:e071/64 scope link 
       valid_lft forever preferred_lft forever

# add flow try forward v1 to v2
$ sudo ovs-ofctl add-flow ovsbridge in_port=4,actions=output:5

# check flow rule
$  sudo ovs-ofctl dump-flows ovsbridge
 cookie=0x0, duration=1138.852s, table=0, n_packets=0, n_bytes=0, in_port=v1 actions=output:v2
 cookie=0x0, duration=32571.512s, table=0, n_packets=518, n_bytes=177156, priority=0 actions=NORMAL

$ sudo ovs-appctl fdb/show ovsbridge
 port  VLAN  MAC                Age
LOCAL     0  a8:7e:ea:be:07:e4  278

$ cat rnd_pkt.py # part of

scapy.sendp(get_random_packet(), iface=v1)

# send 10 packages to v1

and sudo ovs-tcpdump -i v1 do not show package that i send by scapy. i am thinking maybe i shouldn't test by use python-scapy?

what were you expecting?

i expect ovs will copy package from v1 to v2.

if you guys need more info, please tell me. :)

Answer 1

use ip link set $NETCARD promisc on to enable promisc mode, and it works fine.