注明：本文并不对openflow进行分析，本人也是略略知道这个概念，对flowvisor也只是对其API有所测试，更深的源码并未涉及，只是希望该文能对以后的flowvisor研究者提供些许帮助。
一：flowvisor简介
flowvisor是基于openflow的一个中间代理层，其目的在于对物理资源的抽象和分片，从而使得每个控制器下的slice相互隔离，从而做到网络的虚拟化。现有的openflow机制中，主要提供了虚拟交换机如open vswitch，还有控制器如POX,floodlight等，但没有一个很好地资源抽象来实现多用户隔离和分片，flowvisor就是希望完成这个目标。
flowvisor中有几个比较关键的概念。
1.flow:这个其实是对应着openflow报文的10个field的，每一个精确地flow就是这10个filed的一个精确匹配。换言之，由于这10个field总计占256bit，所以这是一个256维的空间，每一个flow就是这个256维空间中的一个点.
2.flowspace:上文提到整个openflow报文在匹配（match）时是一个256维空间中的一个点，那么对于整个网络而言，其flowspace就是256维空间。正如论文中所说的那样,flowspace是他们对匹配头的一个称呼。比如slice1下控制有一个所有协议使用TCP/IP的报文的流，那么这所有符合这个匹配条件的流就是这一个slice所对应的子空间，也就是改slice所拥有的一个flowspace。不同的slice可以对同一个flowspace有权限，但其权限应该不同.此概念不易理解，可以直接参考论文进行理解。
3.slice:网络虚拟化的目的，就是希望不同的用户看到完全隔离的不同的物理网络，但实际网络并非用户看到的那样，所以slice就是一个对物理网络的抽象和划分，就是资源的分割，权限的分配。每一个slice本质上就是一个配置文件，其中对slice的参数进行的描述。在flowvisor中，其存储在数据库中。
flowvisor是基于RPC机制的，目前其使用的是JSON-RPC机制，其大致机制如下：
二：API测试
测试环境：ubuntu12.04 LTS
节点拓扑结构：
flowspace match字段： all or any is used to specify a flow that matches all packets.
in_port=port_no
Matches physical port port_no. Switch ports are numbered as
displayed by fvctl getDeviceInfo DPID.
dl_vlan=vlan
Matches IEEE 802.1q virtual LAN tag vlan. Specify 0xffff as
vlan to match packets that are not tagged with a virtual LAN;
otherwise, specify a number between 0 and 4095, inclusive, as
the 12-bit VLAN ID to match.
dl_src=mac
Matches Ethernet source address mac, which should be specified
as 6 pairs of hexadecimal digits delimited by colons, e.g.
00:0A:E4:25:6B:B0.
dl_dst=mac
Matches Ethernet destination address mac.
dl_type=ethertype
Matches Ethernet protocol type ethertype, which should be speci‐
fied as a integer between 0 and 65535, inclusive, either in dec‐
imal or as a hexadecimal number prefixed by 0x, e.g. 0x0806 to
match ARP packets.
nw_src=ip[/netmask]
Matches IPv4 source address ip, which should be specified as an
IP address, e.g. 192.168.1.1. The optional netmask allows
matching only on an IPv4 address prefix. The netmask is speci‐
ficed "CIDR-style", i.e., 192.168.1.0/24.
nw_dst=ip[/netmask]
Matches IPv4 destination address ip.
nw_proto=proto
Matches IP protocol type proto, which should be specified as a
decimal number between 0 and 255, inclusive, e.g. 6 to match TCP
packets.
nw_tos=tos/dscp
Matches ToS/DSCP (only 6-bits, not modify reserved 2-bits for
future use) field of IPv4 header tos/dscp, which should be spec‐
ified as a decimal number between 0 and 255, inclusive.
tp_src=port
Matches transport-layer (e.g., TCP, UDP, ICMP) source port port,
which should be specified as a decimal number between 0 and
65535 (in the case of TCP or UDP) or between 0 and 255 (in the
case of ICMP), inclusive, e.g. 80 to match packets originating
from a HTTP server.
tp_dst=port
Matches transport-layer destination port port.
slice权限参数：DELEGATE（1）, READ（2）, and WRITE（4）
API测试：
一：add-
1.add-slice：
命令语法：
fvctl add-slice [options] <slicename> <controller-url> <admin-email>
-d DROP, --drop-policy=DROP
Drop rule type; default='exact'
-l, --recv-lldp Slice to receive unknown LLDP; default=False
-f FLOW, --flowmod-limit=FLOW
Slice tcam usage; default is none (-1)
-r RATE, --rate-limit=RATE
Slice control path rate limit; default is none (-1)
-p PASSWD, --password=PASSWD
Slice password
--disabled Disable this slice initially; default=False
输入：fvctl -p 8081 add-slice -l s4 tcp:127.0.0.1 hyd@126.com
输出：
Slice s4 was successfully created
root@icecamel-virtual-machine:/home/icecamel/nv# fvctl -p 8081 list-slice-info s4
Password:
{
"admin-contact": "hyd@126.com",
"admin-status": true,
"controller-url": "tcp:127.0.0.1:6633",
"current-flowmod-usage": 0,
"current-rate": 0,
"drop-policy": "exact",
"recv-lldp": true,
"slice-name": "s4"
}
输入：fvctl -p 8081 add-slice -r 1 s5 tcp:127.0.0.1:6640 hyd@126.com
输出：
Slice s5 was successfully created
root@icecamel-virtual-machine:/home/icecamel/nv# fvctl -p 8081 list-slice-info s5
Password:
{
"admin-contact": "hyd@126.com",
"admin-status": true,
"controller-url": "tcp:127.0.0.1:6640",
"current-flowmod-usage": 0,
"current-rate": 0,
"drop-policy": "exact",
"recv-lldp": false,
"slice-name": "s5"
}
ps：
1.slice不可同名
2.slice的controller不可相同
2.add-flowspace
语法规则： fvctl add-flowspace [options] <flowspace-name> <dpid> <priority> <match> <slice-perm>
Options:
-h, --help show this help message and exit
-q QUEUES, --queues=QUEUES
Define list of queues permitted on this flowspace.
-f FQUEUE, --forced-queue=FQUEUE
Force a queue id upon output action.
注明：match字段如文档开头描述,在这里用perm1=x1,perm=x2的形式列举希望匹配的字段即可，all或者any可以表示所有资源，slice-perm的规则是slice-name1=num1，slice-name2=num2，其中slice权限参数：DELEGATE（1）, READ（2）, and WRITE（4）
输入：fvctl -p 8081 add-flowspace -f 2 fs3 all 100 all s1=5
输出：
FlowSpace fs3 was added with request id 4
{"force-enqueue": 2, "name": "fs3", "slice-action": [{"slice-name": "s1", "permission": 5}], "queues": [], "priority": 100, "dpid": "all_dpids", "id": 5, "match": {"wildcards": 4194303}}
输入：fvctl -p 8081 add-flowspace fs12 all 90 all s2=4
输出：
{
"dpid": "all_dpids",
"force-enqueue": -1,
"id": 7,
"match": {
"wildcards": 4194303
},
"name": "fs12",
"priority": 90,
"queues": [],
"slice-action": [
{
"permission": 4,
"slice-name": "s2"
}
]
}
ps：
如果执行fvctl -p 8081 add-flowspace all 90 all s1=5,s2=5,会出现两个完全一模一样的flowspace，其ID也是一样的，避免使用。
二：list-
1.list-datapaths:Displays the devices
输入： fvctl -p 8081 list-datapaths
输出：Connected switches:
1 : 00:00:1e:e3:d3:5e:b1:47
2 : 00:00:4a:e6:f6:f2:1e:4c
3 : 00:00:72:cf:98:c4:27:41
4 : 00:00:ee:95:d7:4d:0f:49
2.list-datapath-info:Displays information for a connected device
输入：fvctl -p 8081 list-datapath-info 00:00:1e:e3:d3:5e:b1:47 （00:00:1e:e3:d3:5e:b1:47 是dpid）
输出：
{
"connection": "/127.0.0.1:6633-->/127.0.0.1:58527",
"current-flowmod-usage": {
"fvadmin": 0,
"s1": 0,
"s2": 0
},
"dpid": "00:00:1e:e3:d3:5e:b1:47",
"num-ports": 4,
"port-list": [
3,
2,
65534,
1
],
"port-names": [
"b2-b3",
"b2-b1",
"b2",
"p2"
]
}
3.list-datapath-stats：Display statistics for a connected device
输入：fvctl -p 8081 list-datapath-stats 00:00:1e:e3:d3:5e:b1:47
输出：
{
"drop": {
"Total": {}
},
"rx": {
"Total": {
"ECHO_REPLY": 426,
"ECHO_REQUEST": 423,
"FEATURES_REPLY": 1,
"HELLO": 1
},
"classifier-dpid=00:00:1e:e3:d3:5e:b1:47": {
"ECHO_REPLY": 426,
"ECHO_REQUEST": 423,
"FEATURES_REPLY": 1,
"HELLO": 1
}
},
"tx": {
"Total": {
"ECHO_REPLY": 423,
"ECHO_REQUEST": 426,
"FEATURES_REQUEST": 1,
"FLOW_MOD": 1,
"HELLO": 1
},
"classifier-dpid=00:00:1e:e3:d3:5e:b1:47": {
"ECHO_REPLY": 423,
"ECHO_REQUEST": 426,
"FEATURES_REQUEST": 1,
"FLOW_MOD": 1,
"HELLO": 1
}
}
}
4.list-slices: Displays the configured slices
输入：fvctl -p 8081 list-slices
输出：
fvadmin --> enabled
s1 --> enabled
s2 --> enabled
5.list-slice-info：Displays slice information
输入：fvctl -p 8081 list-slice-info s1
输出：
{
"admin-contact": "hyd@126.com",
"admin-status": true,
"controller-url": "tcp:127.0.0.1:6636",
"current-flowmod-usage": 0,
"current-rate": 0,
"drop-policy": "exact",
"recv-lldp": false,
"slice-name": "s1"
}
6.list-slice-stats：Displays statistics about a slice
输入：
fvctl -p 8081 list-slice-stats s1
fvctl -p 8081 list-slice-stats s2
fvctl -p 8081 list-slice-stats fvadmin
输出：
Internal Error -> list-slice-stats: No stats exist for this slice : s1
Internal Error -> list-slice-stats: No stats exist for this slice : s2
Internal Error -> list-slice-stats: No stats exist for this slice : fvadmin
7.list-flowspace:
fvctl list-flowspace [options]
-s SLICE, --slice-name=SLICE Fetch flowspace for specified slice.
-x, --output-hex Displays relevant fields in hex
-p, --pretty-print Pretty print output
--show-disabled Display flowspace for disabled slices
输入1：fvctl -p 8081 list-flowspace
输出1：
{"force-enqueue": -1, "name": "fs1", "slice-action": [{"slice-name": "s1", "permission": 5}], "queues": [], "priority": 100, "dpid": "all_dpids", "id": 1, "match": {"wildcards": 4194263, "nw_proto": 0, "dl_dst": "78:45:c4:2d:72:51"}}
输入2：fvctl -p 8081 list-flowspace -s s1
输出：符合结果
输入3：fvctl -p 8081 list-flowspace -x （可输入slice-name）
输入3：fvctl -p 8081 list-flowspace -p:以列表形式输出
8.list-datapath-flowdb：Displays the contents of the flow db if flow tracking is enabled（跟踪从slice push到switch的flow）
输入：fvctl -p 8081 list-datapath-flowdb 00:00:1e:e3:d3:5e:b1:47
输出：
Flows seen at FlowVisor:
9. list-datapath-flowrewritedb：Displays the rewrites (or expansions) FlowVisor has applied（当controller把一个flow向flowvisor push的时候，flowvisor可能会扩展该流，次命令查阅该扩展）
命令格式：fvctl list-datapath-flowrewritedb slice-name dpid
输入：fvctl -p 8081 list-datapath-flowrewritedb s1 00:00:36:f1:bb:00:67:47
输出：
Rewrites applied by FlowVisor:
输入：fvctl -p 8081 list-datapath-flowrewritedb s1 000036f1bb006747
输出：同上
ps：dpid的格式如果错误，会报错，详情如下：
输入：fvctl -p 8081 list-datapath-flowrewritedb s2 0000-3a02-5569-824c
输出：
HTTP Error 500: Server Error
Rewrites applied by FlowVisor:
Traceback (most recent call last):
File "/usr/local/bin/fvctl", line 1103, in <module>
do_func(gopts, opts, args)
File "/usr/local/bin/fvctl", line 702, in do_listrewritedb
for fbe in ret:
TypeError: 'NoneType' object is not iterable
10:list-fs-status:
命令格式: fvctl list-fs-status <fs-id>
命令作用：查看添加flowspace的请求是否被处理或者请求，返回值有UNKNOWN，PENDING，SUCCESS，或者错误信息
输入：fvctl -p 8081 list-fs-status 1
输出：FlowSpace Request id 1 : SUCCESS
输入: fvctl -p 8081 list-fs-status 10
输出：FlowSpace Request id 10 : UNKNOWN
11：list-fv-health：呈现一些参数
输入：fvctl -p 8081 list-fv-health
输出：
{
"average-delay": 0,
"instant-delay": 0
}
12：list-links:
输入：fvctl -p 8081 list-links
输出：
[
{
"attributes": "fakeLink=true",
"dstDPID": "00:00:42:49:a6:41:b1:41",
"dstPort": "1",
"srcDPID": "00:00:3a:02:55:69:82:4c",
"srcPort": "0"
},
{
"attributes": "fakeLink=true",
"dstDPID": "00:00:62:0b:89:0d:f5:46",
"dstPort": "1",
"srcDPID": "00:00:42:49:a6:41:b1:41",
"srcPort": "0"
},
{
"attributes": "fakeLink=true",
"dstDPID": "00:00:36:f1:bb:00:67:47",
"dstPort": "1",
"srcDPID": "00:00:62:0b:89:0d:f5:46",
"srcPort": "0"
},
{
"attributes": "fakeLink=true",
"dstDPID": "00:00:3a:02:55:69:82:4c",
"dstPort": "1",
"srcDPID": "00:00:36:f1:bb:00:67:47",
"srcPort": "0"
}
]
三：配置
1.get-config:fvctl -p 8081 get-config
结果：Password:
{
"api_jetty_webserver_port": 8081,
"api_webserver_port": 8080,
"checkpointing": false,
"config_name": "default",
"db_version": "2",
"enable-topo-ctrl": false,
"flood-perm": {
"dpid": "all",
"slice-name": "fvadmin"
},
"flow-stats-cache": 30,
"flowmod-limit": {
"fvadmin": {
"00:00:1e:e3:d3:5e:b1:47": -1,
"00:00:4a:e6:f6:f2:1e:4c": -1,
"00:00:72:cf:98:c4:27:41": -1,
"00:00:ee:95:d7:4d:0f:49": -1,
"any": null
},
"s1": {
"00:00:1e:e3:d3:5e:b1:47": -1,
"00:00:4a:e6:f6:f2:1e:4c": -1,
"00:00:72:cf:98:c4:27:41": -1,
"00:00:ee:95:d7:4d:0f:49": -1,
"any": null
},
"s2": {
"00:00:1e:e3:d3:5e:b1:47": -1,
"00:00:4a:e6:f6:f2:1e:4c": -1,
"00:00:72:cf:98:c4:27:41": -1,
"00:00:ee:95:d7:4d:0f:49": -1,
"any": null
}
},
"host": "localhost",
"log_facility": "LOG_LOCAL7",
"log_ident": "flowvisor",
"logging": "NOTE",
"stats-desc": false,
"track-flows": false,
"version": "flowvisor-1.4.0"
}
2.set-config：设置flowvisor的参数：
For flood permissions, if both the dpid and the
slice are given, then that slice is given permission for that dpid. Otherwise,
the given slice is set as the slice global flood permissions. For flowmod
limits, the limit is set per slice per dpid. The dpid in case could be 'any'.
语法规则：
fvctl set-config [options]
Options:
-h, --help show this help message and exit
-f SLICE[,DPID], --flood-perm=SLICE[,DPID]
Set the floodperm
-l SLICE,DPID,LIMIT, --flowmod-limit=SLICE,DPID,LIMIT
Set the flowmod limit.
--enable-tracking Enable flow tracking.
--disable-tracking Disable flow tracking.
--enable-stats-desc Enable stats description hijacking.
--disable-stats-desc Disable stats description hijacking.
--enable-topo-ctrl Enable topology controller.
--disable-topo-ctrl Disable topology controller.
-c CACHE, --flow-stats-cache=CACHE
Set the aging timer for the flow stats cache.
输入：fvctl -p 8081 set-config -f s1 -- enable-tracking
输出：
Configuration has been updated
（调用get-config后可以看到的确成功修改）
输入:fvctl -p 8081 set-config -l s1,00:00:36:f1:bb:00:67:47,10
输出：(修改成功)
root@icecamel-virtual-machine:~# fvctl -p 8081 get-config -s s1 -d 00:00:36:f1:bb:00:67:47
Password:
{
"api_jetty_webserver_port": 8081,
"api_webserver_port": 8080,
"checkpointing": false,
"config_name": "default",
"db_version": "2",
"enable-topo-ctrl": false,
"flood-perm": {
"dpid": "00:00:36:f1:bb:00:67:47",
"slice-name": ""
},
"flow-stats-cache": 30,
"flowmod-limit": {
"s1": {
"00:00:36:f1:bb:00:67:47": 10
}
},
"host": "localhost",
"log_facility": "LOG_LOCAL7",
"log_ident": "flowvisor",
"logging": "NOTE",
"stats-desc": false,
"track-flows": true,
"version": "flowvisor-1.4.0"
}
3.save-config：
语法规则：fvctl save-config <file>
输入： fvctl -p 8081 save-config /home/icecamel/nv/config_test.json
输出：
Config file written to /home/icecamel/nv/config_test.json.
root@icecamel-virtual-machine:/home/icecamel/nv# ls
config_test.json
四：remove与update
1.remove-slice
输入：fvctl -p 8081 remove-slice s4
输出：（正常删除）
2.remove-flowspace
输入：fvctl -p 8081 remove-flowspace fs4
输出：（正常删除）
ps：之前在add-flowspace时通过命令fvctl -p 8081 add-flowspace all 100 all s1=5,s2=5同时生成的两个一模一样的flowspace通过该命令会被同时删除
3.update-admin-password
语法规则：
fvctl update-admin-password [options]
Update the admin password.
Options:
-h, --help show this help message and exit
-p PASSWD, --password=PASSWD
New password for admin.
输入：fvctl update-admin-password -p 123
正常更改
输入:fvctl -p 8081 update-admin-password -p 123
输出：前面的更改生效且这次也成功更改
ps：在修改过后重启，密码修改失效
4.update-flowspace
语法规则：
fvctl update-flowspace [options] <flowspace-name>
Options:
-h, --help show this help message and exit
-d DPID, --dpid=DPID Set the dpid for flowspace entry.
-p PRIO, --priority=PRIO
Set the priority for flowspace entry.
-m MATCH, --match=MATCH
Set the match for flowspace entry.
-s SACT, --slice-action=SACT
Set the slice(s) for flowspace entry.
-q QUEUES, --queues=QUEUES
Define list of queues permitted on this flowspace.
-f FQUEUE, --forced-queue=FQUEUE
Force a queue id upon output action.
输入：fvctl -p 8081 update-flowspace fs6 -m dl_src=0a:a1:f9:da:26:13,nw_proto=0x1
输出：
Flowspace fs6 was updated with request id 10
{
"dpid": "all_dpids",
"force-enqueue": -1,
"id": 10,
"match": {
"dl_src": "0a:a1:f9:da:26:13",
"nw_proto": 1,
"wildcards": 4194267
},
"name": "fs6",
"priority": 101,
"queues": [
2,
3,
4
],
"slice-action": [
{
"permission": 5,
"slice-name": "s2"
}
]
}
（成功修改，且无论是添加flowspace还是修改flowspace，均会使id增加，修改id为x的flowspace，其输出结果id=x+n，且该flowspace 的id变为x）
输入：fvctl -p 8081 update-flowspace fs6 -s s2=5
输出：Flowspace fs6 was updated with request id 11
5.update-slice-password
语法规则：fvctl update-slice-password slice-name -p NewPasswd
输入：fvctl update-slice-password s2 -p 123
输出：Slice password for s2 has been updated.
6.update-slice
语法规则：fvctl update-slice [options] <slicename>
输入：fvctl -p 8081 update-slice s1 -n 192.168.1.133
输出：
Slice s1 has been successfully updated
{
"admin-contact": "hyd@126.com",
"admin-status": true,
"controller-url": "tcp:192.168.1.133:6636",
"current-flowmod-usage": 0,
"current-rate": 0,
"drop-policy": "exact",
"recv-lldp": false,
"slice-name": "s1"
}
输入： fvctl -p 8081 update-slice s1 -d rule
输出：
Slice s1 has been successfully updated
root@icecamel-virtual-machine:/home/icecamel/nv# fvctl -p 8081 list-slice-info s1
Password:
{
"admin-contact": "hyd@126.com",
"admin-status": true,
"controller-url": "tcp:192.168.1.133:6636",
"current-flowmod-usage": 0,
"current-rate": 0,
"drop-policy": "rule",
"recv-lldp": false,
"slice-name": "s1"
}
7.register-event-callback：Registers for events from FlowVisor. Possible events are: DEVICE_CONNECTED,
SLICE_CONNECTED, SLICE_DISCONNECTED and FLOWTABLE_CALLBACK. For
FLOWTABLE_CALLBACK event type dpid has to be input with -d option. More events
may be added later.
语法规则：
fvctl register-event-callback <url> <methodname> <eventtype> <name>