These slides were used for the 3rd Wakame Users Group meeting. http://wakameusersgroup.org/meeting/2014/01/24/wug-003/ Understanding OpenVNet's flow This meeting will be an in dept explanation of OpenVNet's inner workings. We will talk about which flows are added to Open vSwitch in order to create software defined l2 networks.

1. Understanding
OpenVNet’s flow
!1

2. http://github.com/axsh/openvnet/wiki/FlowTable
Sorry for that the instruction is currently written in only Japanese.
English version will come soon…
!2

3. Flows on OVS
[root@dev1 ~]# ovs-ofctl -O Openflow13 dump-flows br0!
!
OFPST_FLOW reply (OF1.3) (xid=0x2):!
cookie=0x900000000000000, duration=2414584.604s, table=0, n_packets=2, n_bytes=684,
priority=1,tun_id=0 actions=drop!
cookie=0x900000000000000, duration=2414584.604s, table=0, n_packets=7, n_bytes=590,
priority=2,in_port=CONTROLLER actions=write_metadata:0x4040000000000/0x40c0000000000,goto_table:7cookie=0x500000000000003, duration=2414582.969s, table=0, n_packets=220, n_bytes=39634,
priority=2,in_port=3 actions=write_metadata:0x700040000000005/0xff000c00ffffffff,goto_table:15!
cookie=0x500000000000001, duration=2414583.972s, table=0, n_packets=1042, n_bytes=133986,
priority=2,in_port=1 actions=write_metadata:0x700080000000001/0xff000c00ffffffff,goto_table:10!
cookie=0x5000000fffffffe, duration=2414584.042s, table=0, n_packets=180, n_bytes=38718,
priority=2,in_port=LOCAL actions=write_metadata:0x40000000000/0xc0000000000,goto_table:6!
cookie=0x500000000000002, duration=2414582.705s, table=0, n_packets=957, n_bytes=111288,
priority=2,in_port=2 actions=write_metadata:0x700040000000004/0xff000c00ffffffff,goto_table:15
Bit unreadable. we created vnflows
!3

4. Flows on OpenVNet
vnflows outputs the flows in a nice format
[root@dev1 ~]# ovs-ofctl -O Openflow13 dump-flows br0 | vnflows!
!
(0): TABLE_CLASSIFIER!
0-00 174 0 =>
actions=write_metadata:REMOTE(0x80000000000/0xc0000000000),goto_table:TABLE_TUNNEL_PORTS(3)!
0-01 2 0 => tun_id=0 actions=drop!
0-02 220 0 => in_port=3 actions=write_metadata:TYPE_INTERFACE|
LOCAL(0x700040000000005/0xff000c00ffffffff),goto_table:TABLE_INTERFACE_EGRESS_CLASSIFIER(15)!
0-02 310 0 => in_port=1 actions=write_metadata:TYPE_INTERFACE|
REMOTE(0x700080000000001/0xff000c00ffffffff),goto_table:TABLE_INTERFACE_INGRESS_CLASSIFIER(10)!
0-02 180 0 => in_port=LOCAL
actions=write_metadata:LOCAL(0x40000000000/0xc0000000000),goto_table:TABLE_LOCAL_PORT(6)!
0-02 4 0 => in_port=CONTROLLER actions=write_metadata:LOCAL|
NO_CONTROLLER(0x4040000000000/0x40c0000000000),goto_table:TABLE_CONTROLLER_PORT(7)
Next : take one piece of flows to see how it is formed….
!4

5. Flows on OpenVNet
Table Num of packets
Priority
Timeout Match Action
!
0-02 220 0 => in_port=3 actions=write_metadata:TYPE_INTERFACE|
LOCAL(0x700040000000005/0xff000c00ffffffff),goto_table:TABLE_INTERFACE_EGRES
S_CLASSIFIER(15)!
“Metadata: a maskable register value that is used to carry
information from one table to the next.”
–OpenFlow Switch Specification Version 1.1.0
!5

6. Metadata
OpenVNet has its own usage of the metadata
63 0
metadata value field
0 - 31 (32bits)
56 55 40 31
metadata flag field
40 - 55 (16bits)
metadata type field
56 - 63 (8bits)
!6

7. Metadata type
METADATA_TYPE_SHIFT = 56!
METADATA_TYPE_MASK = (0xff << METADATA_TYPE_SHIFT)!
!
METADATA_TYPE_DATAPATH = (0x1 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_DP_ROUTE_LINK = (0x2 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_NETWORK = (0x3 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_PORT = (0x4 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_ROUTE = (0x5 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_ROUTE_LINK = (0x6 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_INTERFACE = (0x7 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_EDGE_TO_VIRTUAL = (0x8 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_VIRTUAL_TO_EDGE = (0x9 << METADATA_TYPE_SHIFT)!
METADATA_TYPE_TUNNEL = (0xa << METADATA_TYPE_SHIFT)!
METADATA_TYPE_DP_NETWORK = (0xb << METADATA_TYPE_SHIFT)
METADATA_FLAGS_SHIFT = 40!
METADATA_FLAGS_MASK = (0xffff << METADATA_FLAGS_SHIFT)!
!
METADATA_FLAG_VIRTUAL = (0x001 << METADATA_FLAGS_SHIFT)!
METADATA_FLAG_PHYSICAL = (0x002 << METADATA_FLAGS_SHIFT)!
METADATA_FLAG_LOCAL = (0x004 << METADATA_FLAGS_SHIFT)!
METADATA_FLAG_REMOTE = (0x008 << METADATA_FLAGS_SHIFT)!
METADATA_FLAG_FLOOD = (0x010 << METADATA_FLAGS_SHIFT)!
METADATA_FLAG_VIF = (0x020 << METADATA_FLAGS_SHIFT)!
METADATA_FLAG_MAC2MAC = (0x040 << METADATA_FLAGS_SHIFT)!
METADATA_FLAG_IGNORE_MAC2MAC = (0x100 << METADATA_FLAGS_SHIFT)
Metadata flag
!7

8. Matching metadata
Suppose a flow contains the following condition match
metadata=TYPE_INTERFACE(0x70000000000000d/0xff000000ffffffff)
& filter == 0x70000000000000d
ex.)
metadata
metadata carried from another table
10-10 128 0 => metadata=TYPE_INTERFACE(0x700000000000001/0xff000000ffffffff)
actions=goto_table:TABLE_INTERFACE_INGRESS_MAC(11)
!8

9. We look at…
Packet from VM1 to VM5 (only ARP REQUEST)
but it helps you understand flows for other packets
!9

10. VM1 sends an ARP REQUEST packet
0-02 221 0 => in_port=2 actions=write_metadata:TYPE_INTERFACE|
LOCAL(0x700040000000004/0xff000c00ffffffff),goto_table:TABLE_INTERFACE_EGRESS_CLASSIFIER
(15)
public line
datapath
eth0
eth1
2 3
VM1
vna
VM2
host1
Don’t forget metadata value!!
we use a lot…
metadata = 0x700040000000004
!10

11. 15-40 5 0 =>
arp,metadata=TYPE_INTERFACE(0x700000000000004/0xff000000ffffffff)
,dl_src=02:00:00:00:00:01,arp_spa=10.101.0.10,arp_sha=02:00:00:00
:00:01
actions=write_metadata:TYPE_NETWORK(0x300000000000002/0xff000000f
fffffff),goto_table:TABLE_INTERFACE_EGRESS_FILTER(18)
metadata = 0x700040000000004
public line
datapath
eth0
eth1
2 3
VM1
vna
VM2
host1
MAC address
02:00:00:00:00:01
!
IP address
10.101.0.10
0x300040000000002
!11

12. 18-00 612 0 =>
actions=goto_table:TABLE_NETWORK_SRC_CLASSIFIER(20)!
!
!
20-40 369 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=goto_table:TABLE_VIRTUAL_SRC(21)!
!
!
21-90 432 0 =>
metadata=LOCAL(0x40000000000/0xc0000000000)
actions=goto_table:TABLE_ROUTE_INGRESS_INTERFACE(30)
metadata = 0x300040000000002
!12

13. 30-00 844 0 =>
actions=goto_table:TABLE_NETWORK_DST_CLASSIFIER(40)!
!
!
40-40 307 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=goto_table:TABLE_VIRTUAL_DST(41)!
!
!
41-30 12 0 => dl_dst=ff:ff:ff:ff:ff:ff
actions=goto_table:TABLE_FLOOD_SIMULATED(50)
metadata = 0x300040000000002
!13

14. 50-00 9 0 =>
actions=goto_table:TABLE_FLOOD_LOCAL(51)!
!
!
51-01 3 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=output:2,goto_table:TABLE_FLOOD_SEGMENT(52)!
!
52-01 2 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=set_field:02:00:00:bb:00:01->eth_dst,output:
1,set_field:ff:ff:ff:ff:ff:ff-
>eth_dst,goto_table:TABLE_FLOOD_TUNNELS(53)
metadata = 0x300040000000002
datapath
eth0
eth1
2 3
VM1
vna
VM2
host1
MAC address
02:00:00:00:00:01
!
IP address
10.101.0.10
!14

15. DatapathNetwork
52-01 2 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=set_field:02:00:00:bb:00:01->eth_dst,output:
1,set_field:ff:ff:ff:ff:ff:ff-
>eth_dst,goto_table:TABLE_FLOOD_TUNNELS(53)
Pseudo broadcast MAC address internally used by OpenVNet
datapath
eth0
eth1
2 3
VM1
vna
VM2
datapath
eth0
eth1
2 3
VM3
vna
VM4
host1 host2
Modify 02:00:00:bb:00:01
to ff:ff:ff:ff:ff:ff then send
to VM3
!15

16. Set tunnel ID then output to GRE port
53-01 2 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=set_field:0x80000002->tun_id,output:19
public line
datapath
eth0
eth1
2 3
VM1
vna
L3 switch
GRE tunnel
VM2
datapath
eth0
eth1
2 3
VM5
vna
VM6
host1 host3
!16

17. Packet arrived to host3
Write METADATA_FLAG_REMOTE because the packet came
from another host
0-00 345 0 =>
actions=write_metadata:REMOTE(0x80000000000/0xc0000000000),goto_
table:TABLE_TUNNEL_PORTS(3)
metadata = 0x000080000000002
!17
tun_id = 0x80000002

18. port number of GRE tunnel on host3
3-30 175 0 => in_port=38
actions=goto_table:TABLE_TUNNEL_NETWORK_IDS(4)!
!
4-30 174 0 => tun_id=0x80000002
actions=write_metadata:TYPE_NETWORK(0x300000000000002/0xff000000
ffffffff),goto_table:TABLE_NETWORK_SRC_CLASSIFIER(20)!
!
20-40 391 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=goto_table:TABLE_VIRTUAL_SRC(21)
0x300080000000002
metadata = 0x000080000000002
!18
tun_id = 0x80000002

19. Mac learning
21-81 5 0 => arp,metadata=TYPE_NETWORK|
REMOTE(0x300080000000002/0xff000c00ffffffff)
actions=learn(table=41,idle_timeout=36000,priority=35,cookie=0x4000000000
00002,metadata=0x300040000000002,NXM_OF_ETH_DST[]=NXM_OF_ETH_SRC[],load:N
XM_NX_TUN_ID[]-
>NXM_NX_TUN_ID[],output:NXM_OF_IN_PORT[]),goto_table:TABLE_ROUTE_INGRESS_
INTERFACE(30)
public line
datapath
eth0
MAC address
02:00:00:00:00:01
!
IP address
10.101.0.10
eth1
2 3
VM1
vna
GRE tunnel L3 switch
VM2
datapath
eth0
2 3
VM5
vna
VM6
Learning MAC address!
02:00:00:00:00:01!
comes from eth0
host1 host3
!19

20. 30-00 1223 0 =>
actions=goto_table:TABLE_NETWORK_DST_CLASSIFIER(40)!
!
!
40-40 307 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=goto_table:TABLE_VIRTUAL_DST(41)!
!
!
41-30 11 0 => dl_dst=ff:ff:ff:ff:ff:ff
actions=goto_table:TABLE_FLOOD_SIMULATED(50)
metadata = 0x300080000000002
!20

21. 50-00 7 0 =>
actions=goto_table:TABLE_FLOOD_LOCAL(51)!
51-01 3 0 =>
metadata=TYPE_NETWORK(0x300000000000002/0xff000000ffffffff)
actions=output:2,goto_table:TABLE_FLOOD_SEGMENT(52)!
!
52-10 6 0 =>
metadata=REMOTE(0x80000000000/0xc0000000000) actions=drop
Packet public line
is sent to port 2,
which is associated with VM5
datapath
eth0
It then drops the packet
since no more forwarding is needed.
metadata = 0x300080000000002
eth1
2 3
VM1
vna
L3 switch
GRE tunnel
VM2
datapath
eth0
2 3
VM5
vna
VM6
host1 host3
!21