fgraph.go

/***
Copyright 2014 Cisco Systems Inc. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package ofctrl

// This file defines the forwarding graph API

import (
	"github.com/shaleman/libOpenflow/openflow13"
)

// This implements a forwarding graph.
// Forwarding graph is local to each switch. It is roughly structured as follows
//
//         +------------+
//         | Controller |
//         +------------+
//                |
//      +---------+---------+
//      |                   |
// +----------+        +----------+
// | Switch 1 |        | Switch 2 |
// +----------+        +----------+
//       |
//       +--------------+---------------+
//       |              |               |
//       V              V
// +---------+      +---------+     +---------+
// | Table 1 |  +-->| Table 2 |  +->| Table 3 |
// +---------+  |   +---------+  |  +---------+
//      |       |        |       |      |
// +---------+  |   +---------+  |  +--------+     +------+
// | Flow 1  +--+   | Flow 1  +--+  | Flow 1 +---->| Drop |
// +---------+      +---------+     +--------+     +------+
//      |
// +---------+            +----------+
// | Flow 2  +----------->+ OutPut 1 |
// +---------+            +----------+
//      |
// +---------+                 +----------+
// | Flow 3  +---------------->| Output 2 |
// +---------+                 +----------+
//      |                            ^
// +---------+       +---------+     |      +----------+
// | Flow 4  +------>| Flood 1 +-----+----->| Output 3 |
// +---------+       +---------+     |      +----------+
//      |                            |
// +---------+     +-----------+     |      +----------+
// | Flow 5  +---->| Multipath |     +----->| Output 4 |
// +---------+     +-----+-----+            +----------+
//                       |
//          +------------+-------------+
//          |            |             |
//    +----------+  +----------+  +----------+
//    | Output 5 |  | Output 6 |  | Output 7 |
//    +----------+  +----------+  +----------+
//
//
// Forwarding graph is made up of Fgraph elements. Currently there are three
// kinds of elements (i) Table (ii) Flow (iii) Output. In future we will support
// Two additional types (iv) Flood and (v) Multipath.
// - Each Switch has a set of Tables. Switch has a special DefaultTable where
//   All packet lookups start.
// - Each Table contains list of Flows. Each Flow has a Match which determines
//   which packets match the flow and a NextElem which it points to
// - A Flow can point to following elements
//      (a) Table - This moves the forwarding lookup to specified table
//      (b) Output - This causes the packet to be sent out
//      (c) Flood  - This causes the packet to be flooded to list of ports
//      (d) Multipath - This causes packet to be load balanced across set of
//                      ports. This can be used for link aggregation and ECMP
// - There are three kinds of outputs
//      (i) drop - which causes the packet to be dropped
//      (ii) toController - sends the packet to controller
//      (iii) port - sends the packet out of specified port
// - A flow can have additional actions like (i) Set Vlan tag (ii) Set metadata
//   Which is used for setting VRF for a packet (iii) Set VNI/tunnel header etc
//
// ----------------------------------------------------------------
// Example usage:
// // Create all tables
// rxVlanTbl := switch.NewTable(1)
// macSaTable := switch.NewTable(2)
// macDaTable := switch.NewTable(3)
// ipTable := switch.NewTable(4)
// inpTable := switch.DefaultTable() // table 0. i.e starting table
//
// // Discard mcast source mac
// dscrdMcastSrc := inpTable.NewFlow(FlowMatch{
//                                  &McastSrc: { 0x01, 0, 0, 0, 0, 0 }
//                                  &McastSrcMask: { 0x01, 0, 0, 0, 0, 0 }
//                                  }, 100)
// dscrdMcastSrc.Next(switch.DropAction())
//
// // All valid packets go to vlan table
// validInputPkt := inpTable.NewFlow(FlowMatch{}, 1)
// validInputPkt.Next(rxVlanTbl)
//
// // Set access vlan for port 1 and go to mac lookup
// tagPort := rxVlanTbl.NewFlow(FlowMatch{
//                              InputPort: Port(1)
//                              }, 100)
// tagPort.SetVlan(10)
// tagPort.Next(macSaTable)
//
// // Match on IP dest addr and forward to a port
// ipFlow := ipTable.NewFlow(FlowParams{
//                           IpDa: &net.IPv4("10.10.10.10")
//                          }, 100)
//
// outPort := switch.NewOutputPort(OutParams{
//                              OutPort: Port(10)
//                              }, 100)
// ipFlow.Next(outPort)
//

type FgraphElem interface {
	// Returns the type of fw graph element
	Type() string

	// Returns the formatted instruction set.
	// This is used by the previous Fgraph element to install instruction set
	// in the flow entry
	GetFlowInstr() openflow13.Instruction
}