The Road to Ryu: Hi Ryu

参考：

ryu入门教程

ryu

ryu/ryu Structure

-ryu/ryu
    app
    base
    cmd
    contrib
    controller
    lib
    ofproto
    services
    tests
    topology

ryu/ryu/app

基于ryu控制器开发的app，内含ryu的图形界面、北向防火墙、北向QoS、简易L2交换机、L3路由器等。

ryu/ryu/base

内含app_manager.py脚本，用于加载ryu应用程序，接受从APP发送过来的信息，同时也完成消息的路由。

定义了两大基类：RyuApp和AppManager。RyuApp定义了App的基本属性，AppManager则定义了用于管理多个App的方法和属性。

ryu/ryu/controller

该文件夹中含有许多关键的ryu源码文件，这里提一下controller.py，该文件中含有两个十分重要的类：

class OpenFlowController(object)

class Datapath(ofproto_protocol.ProtocolDesc)

其中类OpenFlowController定义了构建一个控制器的基本方法和属性，DataPath是用于描述OpenFlow控制器和交换机是如何连接的类：

    A class to describe an OpenFlow switch connected to this controller.

    An instance has the following attributes.

    .. tabularcolumns:: |l|L|

    ==================================== ======================================
    Attribute                            Description
    ==================================== ======================================
    id                                   64-bit OpenFlow Datapath ID.
                                         Only available for
                                         ryu.controller.handler.MAIN_DISPATCHER
                                         phase.
    ofproto                              A module which exports OpenFlow
                                         definitions, mainly constants appeared
                                         in the specification, for the
                                         negotiated OpenFlow version.  For
                                         example, ryu.ofproto.ofproto_v1_0 for
                                         OpenFlow 1.0.
    ofproto_parser                       A module which exports OpenFlow wire
                                         message encoder and decoder for the
                                         negotiated OpenFlow version.
                                         For example,
                                         ryu.ofproto.ofproto_v1_0_parser
                                         for OpenFlow 1.0.
    ofproto_parser.OFPxxxx(datapath,...) A callable to prepare an OpenFlow
                                         message for the given switch.  It can
                                         be sent with Datapath.send_msg later.
                                         xxxx is a name of the message.  For
                                         example OFPFlowMod for flow-mod
                                         message.  Arguemnts depend on the
                                         message.
    set_xid(self, msg)                   Generate an OpenFlow XID and put it
                                         in msg.xid.
    send_msg(self, msg)                  Queue an OpenFlow message to send to
                                         the corresponding switch.  If msg.xid
                                         is None, set_xid is automatically
                                         called on the message before queueing.
    send_packet_out                      deprecated
    send_flow_mod                        deprecated
    send_flow_del                        deprecated
    send_delete_all_flows                deprecated
    send_barrier                         Queue an OpenFlow barrier message to
                                         send to the switch.
    send_nxt_set_flow_format             deprecated
    is_reserved_port                     deprecated
    ==================================== ======================================

ryu/ryu/cmd

定义了ryu的命令系统。

ryu/ryu/contrib

社区贡献者的代码。

ryu/ryu/lib

该目录下定义了一些数据报的格式和数据结构，及诸多网络协议。

ryu/ryu/ofproto

该目录下的文件分为两类，一类定义协议的数据结构，另外一类用于协议报文解析。

ryu/ryu/services

完成了bgp、vrrp协议及ovsdb的实现。

ryu/ryu/tests

用于测试。

ryu/ryu/topology

定义了自定义拓扑文件中需要的一些模块和方法，其中的关键文件是switches.py，完成了对一整套交换机处理流程的定义。

Hi Ryu

Env:

Mac OS X.

0.pre:

    python-eventlet
    python-routes
    python-webob
    python-paramiko

1.install it:

git clone git://github.com/osrg/ryu.git
cd ryu
sudo pip3 install -r tools/pip-requires
sudo python setup.py install

2.执行：

ryu-manager simple_switch.py

2017/2/29