OVS 精确删除流表

前言

今天看了sdnlab小姐姐的mininet教程之后，看到有一个下流表的操作，优先级没能下成功，然后回来实验一下，这个问题是解决了，不过遇到了一个小问题，ovs如何精确删除流表

OVS精确删除流表

查找了若干文献、文档均无果

• 问题描述

以下是我的流表

OFPST_FLOW reply (OF1.3) (xid=0x2):

 cookie=0x0, duration=50.313s, table=0, n_packets=55, n_bytes=3878, priority=0 actions=CONTROLLER:65535

 cookie=0x0, duration=2.921s, table=0, n_packets=0, n_bytes=0, priority=100,in_port=1 actions=drop

 cookie=0x0, duration=42.320s, table=0, n_packets=167, n_bytes=10020, priority=65535,dl_dst=01:80:c2:00:00:0e,dl_type=0x88cc actions=CONTROLLER:65535

 cookie=0x0, duration=2746.808s, table=0, n_packets=20, n_bytes=1400, priority=1,in_port=3,dl_dst=de:34:d2:d3:1b:1e actions=output:2

 cookie=0x0, duration=2746.809s, table=0, n_packets=20, n_bytes=1400, priority=1,in_port=2,dl_dst=72:11:da:8b:c8:6e actions=output:3

 cookie=0x0, duration=2746.814s, table=0, n_packets=20, n_bytes=1400, priority=1,in_port=3,dl_dst=66:6b:6d:d1:97:cc actions=output:1

 cookie=0x0, duration=2746.820s, table=0, n_packets=28, n_bytes=2128, priority=1,in_port=2,dl_dst=66:6b:6d:d1:97:cc actions=output:1

 cookie=0x0, duration=47.854s, table=0, n_packets=3, n_bytes=182, priority=1,in_port=1,dl_dst=72:11:da:8b:c8:6e actions=output:3

 cookie=0x0, duration=47.865s, table=0, n_packets=3, n_bytes=182, priority=1,in_port=1,dl_dst=de:34:d2:d3:1b:1e actions=output:2

目的是为了删除上面的第二条流表

cookie=0x0, duration=2.921s, table=0, n_packets=0, n_bytes=0, priority=100,in_port=1 actions=drop

试了各种，优先级匹配，动作匹配均发现这不是其关键字，无法做到，稍稍得到OVS命令行的缺陷无法精确删除流表（希望大家打脸）～～ 想了想堂堂一个OVS不支持精确删除流表，我以前做的那些控制器删除流表的实验是怎么实现的，其本质不是也是调用底层吗？以前ODL是根据table-id,flow-id，我通过命令行查看的流表其中并无flow-id该关键字。

后来还是向控制器求助了，查看了RYU的官方RestFul接口，其删除流表可以用到优先级以及对应的匹配域得到

# delete flow entry strictly matching wildcards and priority

# POST /stats/flowentry/delete_strict

于是我就用POSTMAN搞了

然后就删除了

OFPST_FLOW reply (OF1.3) (xid=0x2):

 cookie=0x0, duration=62.799s, table=0, n_packets=55, n_bytes=3878, priority=0 actions=CONTROLLER:65535

 cookie=0x0, duration=54.806s, table=0, n_packets=169, n_bytes=10140, priority=65535,dl_dst=01:80:c2:00:00:0e,dl_type=0x88cc actions=CONTROLLER:65535

 cookie=0x0, duration=2759.294s, table=0, n_packets=20, n_bytes=1400, priority=1,in_port=3,dl_dst=de:34:d2:d3:1b:1e actions=output:2

 cookie=0x0, duration=2759.295s, table=0, n_packets=20, n_bytes=1400, priority=1,in_port=2,dl_dst=72:11:da:8b:c8:6e actions=output:3

 cookie=0x0, duration=2759.300s, table=0, n_packets=20, n_bytes=1400, priority=1,in_port=3,dl_dst=66:6b:6d:d1:97:cc actions=output:1

 cookie=0x0, duration=2759.306s, table=0, n_packets=28, n_bytes=2128, priority=1,in_port=2,dl_dst=66:6b:6d:d1:97:cc actions=output:1

 cookie=0x0, duration=60.340s, table=0, n_packets=3, n_bytes=182, priority=1,in_port=1,dl_dst=72:11:da:8b:c8:6e actions=output:3

 cookie=0x0, duration=60.351s, table=0, n_packets=3, n_bytes=182, priority=1,in_port=1,dl_dst=de:34:d2:d3:1b:1e actions=output:2

结论

与其说是结论，我觉得更适合说是我的猜想，OVS依旧也是向上层提供相应的OpenFlow的接口，供与控制器交互，我们使用命令行去对OVS进行操纵，其实本身也有利用一些OVS的接口，只是我们命令行的接口封装得并不是那么全面，所有有些操作还是得通过控制器层面去进行，命令行可以作为一种辅助的工具。