删除与特定 cookie 匹配的流 - OpenVSwitch 支持 OpenFlow 1.3.5 规范

Question

根据 OpenFlow 1.3.5 规范，第 44 页指定以下内容：

Modify and delete commands can also be filtered by cookie value, if the cookie_mask field contains a value other than 0. This constraint is that the bits specified by the cookie_mask in both the cookie field of the flow mod and a flow entry’s cookie value must be equal. In other words, (flow entry.cookie&flow mod.cookie mask) == (flow mod.cookie&flow mod.cookie mask).

现在，使用基于 Ryu python 的控制器，我尝试通过指定流的 cookie 值来删除流，但该过程没有成功。

以下代码是我使用的测试示例。

from ryu.base.app_manager import RyuApp
from ryu.controller.dpset import EventDP
from ryu.controller.handler import MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_3
from ryu.ofproto import ether, inet

class MPLS_Testing(RyuApp):
  OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]

  @set_ev_cls(EventDP, MAIN_DISPATCHER)
  def switch_connect_event(self, ev):
    ofp_parser = ev.dp.ofproto_parser
    ofp = ev.dp.ofproto
    datapath_obj = ev.dp
    if ev.enter:
      datapath_obj.send_msg(  # Removes all flows registered in this switch.
        ofp_parser.OFPFlowMod(
          datapath=datapath_obj,
          table_id=ofp.OFPTT_ALL,
          command=ofp.OFPFC_DELETE,
          out_port=ofp.OFPP_ANY,
          out_group=ofp.OFPG_ANY,
        )
      )
      add_label_flow = ofp_parser.OFPFlowMod(
        datapath=datapath_obj,            
        cookie=1,        
        table_id=0,
        command=ofp.OFPFC_ADD,
        match=ofp_parser.OFPMatch(
          in_port=1
        ),
        instructions=[
          ofp_parser.OFPInstructionActions(
            ofp.OFPIT_APPLY_ACTIONS,
            [
              ofp_parser.OFPActionPushMpls(),
              ofp_parser.OFPActionSetField(mpls_label=16),
            ]
          ),
          ofp_parser.OFPInstructionGotoTable(table_id=1),
        ]
      )
      datapath_obj.send_msg(add_label_flow)

      add_label_flow2 = ofp_parser.OFPFlowMod(
        datapath=datapath_obj,            
        cookie=2,
        table_id=1,
        command=ofp.OFPFC_ADD,            
        match=ofp_parser.OFPMatch(
          in_port=1
        ),
        instructions=[
          ofp_parser.OFPInstructionActions(
            ofp.OFPIT_APPLY_ACTIONS,
            [
              ofp_parser.OFPActionPushMpls(),
              ofp_parser.OFPActionSetField(mpls_label=12),
            ]
          ),
          ofp_parser.OFPInstructionGotoTable(table_id=2),
        ]
      )
      datapath_obj.send_msg(add_label_flow2)

      # Deletes flow with cookie equal to 2.
      datapath_obj.send_msg(
        ofp_parser.OFPFlowMod(
          cookie=2,
          cookie_mask=0xFFFFFFFFFFFFFFFF,
          datapath=datapath_obj,
          command=ofp.OFPFC_DELETE,
          out_port=ofp.OFPP_ANY,
          out_group=ofp.OFPG_ANY,
        )
      )

谁能告诉我 OpenVSwitch 2.9 在从表中删除流时是否支持 cookie 匹配？ OpenFlow 1.3.5 规范明确指出，当 cookie_mask 不为零时，删除命令也可以使用 cookie 值过滤流。目前，我有点迷路了。

Answer 1

我已经弄清楚缺少什么了。

@pchaigno 感谢您的支持。

OFPFlowMod 中似乎缺少 table_id = OFPTT_ALL 信息。 Ryu 似乎在初始化对象时将该值默认为零。因此，当 OFPFlowMod 消息用作 OFPFC_DELETE 命令时，Ryu 默认添加 table_id = 0 匹配要求。

因此，当使用 Ryu 时，从 Switch 中删除 cookie 等于 2 的流的正确消息结构是：

ofp_parser.OFPFlowMod(
    datapath=datapath_obj,
    cookie=2,
    cookie_mask=0xFFFFFFFFFFFFFFFF,
    table_id=ofp.OFPTT_ALL,
    command=ofp.OFPFC_DELETE,
    out_port=ofp.OFPP_ANY,
    out_group=ofp.OFPG_ANY
)

根据标准，out_port需要等于OFPP_ANY并且 out_group字段需要等于OFPG_ANY，否则两个字段都将被视为匹配要求。 table_id 字段似乎遵循几乎相同的逻辑，需要 table_id = OFPTT_ALL 匹配所有表。

我现在认为这个问题已经解决了。

删除与特定 cookie 匹配的流 - OpenVSwitch 支持 OpenFlow 1.3.5 规范

Delete Flows matching specific cookie - OpenFlow 1.3.5 Spec support by OpenVSwitch

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