329 lines
17 KiB
C++
329 lines
17 KiB
C++
// RHRouter.h
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//
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// Author: Mike McCauley (mikem@airspayce.com)
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// Copyright (C) 2011 Mike McCauley
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// $Id: RHRouter.h,v 1.9 2014/08/10 20:55:17 mikem Exp $
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#ifndef RHRouter_h
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#define RHRouter_h
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#include <RHReliableDatagram.h>
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// Default max number of hops we will route
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#define RH_DEFAULT_MAX_HOPS 30
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// The default size of the routing table we keep
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#define RH_ROUTING_TABLE_SIZE 10
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// Error codes
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#define RH_ROUTER_ERROR_NONE 0
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#define RH_ROUTER_ERROR_INVALID_LENGTH 1
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#define RH_ROUTER_ERROR_NO_ROUTE 2
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#define RH_ROUTER_ERROR_TIMEOUT 3
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#define RH_ROUTER_ERROR_NO_REPLY 4
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#define RH_ROUTER_ERROR_UNABLE_TO_DELIVER 5
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// This size of RH_ROUTER_MAX_MESSAGE_LEN is OK for Arduino Mega, but too big for
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// Duemilanova. Size of 50 works with the sample router programs on Duemilanova.
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#define RH_ROUTER_MAX_MESSAGE_LEN (RH_MAX_MESSAGE_LEN - sizeof(RHRouter::RoutedMessageHeader))
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//#define RH_ROUTER_MAX_MESSAGE_LEN 50
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// These allow us to define a simulated network topology for testing purposes
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// See RHRouter.cpp for details
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//#define RH_TEST_NETWORK 1
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//#define RH_TEST_NETWORK 2
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//#define RH_TEST_NETWORK 3
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//#define RH_TEST_NETWORK 4
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/////////////////////////////////////////////////////////////////////
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/// \class RHRouter RHRouter.h <RHRouter.h>
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/// \brief RHReliableDatagram subclass for sending addressed, optionally acknowledged datagrams
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/// multi-hop routed across a network.
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///
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/// Manager class that extends RHReliableDatagram to define addressed messages
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/// That are reliably transmitted and routed across a network. Each message is transmitted reliably
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/// between each hop in order to get from the source node to the destination node.
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///
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/// With RHRouter, routes are hard wired. This means that each node must have programmed
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/// in it how to reach each of the other nodes it will be trying to communicate with.
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/// This means you must specify the next-hop node address for each of the destination nodes,
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/// using the addRouteTo() function.
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///
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/// When sendtoWait() is called with a new message to deliver, and the destination address,
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/// RHRouter looks up the next hop node for the destination node. It then uses
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/// RHReliableDatagram to (reliably) deliver the message to the next hop
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/// (which is expected also to be running an RHRouter). If that next-hop node is not
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/// the final destination, it will also look up the next hop for the destination node and
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/// (reliably) deliver the message to the next hop. By this method, messages can be delivered
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/// across a network of nodes, even if each node cannot hear all of the others in the network.
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/// Each time a message is received for another node and retransmitted to the next hop,
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/// the HOPS filed in teh header is incremented. If a message is received for routing to another node
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/// which has exceed the routers max_hops, the message wioll be dropped and ignored.
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/// This helps prevent infinite routing loops.
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///
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/// RHRouter supports messages with a dest of RH_BROADCAST_ADDRESS. Such messages are not routed,
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/// and are broadcast (once) to all nodes within range.
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///
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/// The recvfromAck() function is responsible not just for receiving and delivering
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/// messages addressed to this node (or RH_BROADCAST_ADDRESS), but
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/// it is also responsible for routing other message to their next hop. This means that it is important to
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/// call recvfromAck() or recvfromAckTimeout() frequently in your main loop. recvfromAck() will return
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/// false if it receives a message but it is not for this node.
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///
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/// RHRouter does not provide reliable end-to-end delivery, but uses reliable hop-to-hop delivery.
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/// If a message is unable to be delivered to an end node during to a delivery failure between 2 hops,
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/// the source node will not be told about it.
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///
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/// Note: This class is most useful for networks of nodes that are essentially static
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/// (i.e. the nodes dont move around), and for which the
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/// routing never changes. If that is not the case for your proposed network, see RHMesh instead.
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///
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/// \par The Routing Table
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///
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/// The routing table is a local table in RHRouter that holds the information about the next hop node
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/// address for each destination address you may want to send a message to. It is your responsibility
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/// to make sure every node in an RHRouter network has been configured with a unique address and the
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/// routing information so that messages are correctly routed across the network from source node to
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/// destination node. This is usually done once in setup() by calling addRouteTo().
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/// The hardwired routing will in general be different on each node, and will depend on the physical
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/// topololgy of the network.
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/// You can also use addRouteTo() to change a route and
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/// deleteRouteTo() to delete a route at run time. Youcan also clear the entire routing table
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///
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/// The Routing Table has limited capacity for entries (defined by RH_ROUTING_TABLE_SIZE, which is 10)
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/// if more than RH_ROUTING_TABLE_SIZE are added, the oldest (first) one will be removed by calling
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/// retireOldestRoute()
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///
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/// \par Message Format
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///
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/// RHRouter add to the lower level RHReliableDatagram (and even lower level RH) class message formats.
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/// In those lower level classes, the hop-to-hop message headers are in the RH message headers,
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/// and are handled automcatically by tyhe RH hardware.
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/// RHRouter and its subclasses add an end-to-end addressing header in the payload of the RH message,
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/// and before the RHRouter application data.
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/// - 1 octet DEST, the destination node address (ie the address of the final
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/// destination node for this message)
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/// - 1 octet SOURCE, the source node address (ie the address of the originating node that first sent
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/// the message).
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/// - 1 octet HOPS, the number of hops this message has traversed so far.
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/// - 1 octet ID, an incrementing message ID for end-to-end message tracking for use by subclasses.
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/// Not used by RHRouter.
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/// - 1 octet FLAGS, a bitmask for use by subclasses. Not used by RHRouter.
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/// - 0 or more octets DATA, the application payload data. The length of this data is implicit
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/// in the length of the entire message.
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///
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/// You should be careful to note that there are ID and FLAGS fields in the low level per-hop
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/// message header too. These are used only for hop-to-hop, and in general will be different to
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/// the ones at the RHRouter level.
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///
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/// \par Testing
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///
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/// Bench testing of such networks is notoriously difficult, especially simulating limited radio
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/// connectivity between some nodes.
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/// To assist testing (both during RH development and for your own networks)
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/// RHRouter.cpp has the ability to
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/// simulate a number of different small network topologies. Each simulated network supports 4 nodes with
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/// addresses 1 to 4. It operates by pretending to not hear RH messages from certain other nodes.
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/// You can enable testing with a \#define TEST_NETWORK in RHRouter.h
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/// The sample programs rf22_mesh_* rely on this feature.
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///
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/// Part of the Arduino RH library for operating with HopeRF RH compatible transceivers
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/// (see http://www.hoperf.com)
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class RHRouter : public RHReliableDatagram
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{
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public:
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/// Defines the structure of the RHRouter message header, used to keep track of end-to-end delivery parameters
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typedef struct
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{
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uint8_t dest; ///< Destination node address
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uint8_t source; ///< Originator node address
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uint8_t hops; ///< Hops traversed so far
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uint8_t id; ///< Originator sequence number
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uint8_t flags; ///< Originator flags
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// Data follows, Length is implicit in the overall message length
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} RoutedMessageHeader;
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/// Defines the structure of a RHRouter message
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typedef struct
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{
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RoutedMessageHeader header; ///< end-to-end delivery header
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uint8_t data[RH_ROUTER_MAX_MESSAGE_LEN]; ///< Application payload data
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} RoutedMessage;
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/// Values for the possible states for routes
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typedef enum
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{
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Invalid = 0, ///< No valid route is known
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Discovering, ///< Discovering a route (not currently used)
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Valid ///< Route is valid
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} RouteState;
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/// Defines an entry in the routing table
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typedef struct
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{
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uint8_t dest; ///< Destination node address
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uint8_t next_hop; ///< Send via this next hop address
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uint8_t state; ///< State of this route, one of RouteState
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} RoutingTableEntry;
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/// Constructor.
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/// \param[in] driver The RadioHead driver to use to transport messages.
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/// \param[in] thisAddress The address to assign to this node. Defaults to 0
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RHRouter(RHGenericDriver& driver, uint8_t thisAddress = 0);
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/// Initialises this instance and the radio module connected to it.
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/// Overrides the init() function in RH.
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/// Sets max_hops to the default of RH_DEFAULT_MAX_HOPS (30)
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bool init();
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/// Sets the max_hops to the given value
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/// This controls the maximum number of hops allowed between source and destination nodes
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/// Messages that are not delivered by the time their HOPS field exceeds max_hops on a
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/// routing node will be dropped and ignored.
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/// \param [in] max_hops The new value for max_hops
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void setMaxHops(uint8_t max_hops);
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/// Adds a route to the local routing table, or updates it if already present.
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/// If there is not enough room the oldest (first) route will be deleted by calling retireOldestRoute().
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/// \param [in] dest The destination node address. RH_BROADCAST_ADDRESS is permitted.
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/// \param [in] next_hop The address of the next hop to send messages destined for dest
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/// \param [in] state The satte of the route. Defaults to Valid
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void addRouteTo(uint8_t dest, uint8_t next_hop, uint8_t state = Valid);
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/// Finds and returns a RoutingTableEntry for the given destination node
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/// \param [in] dest The desired destination node address.
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/// \return pointer to a RoutingTableEntry for dest
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RoutingTableEntry* getRouteTo(uint8_t dest);
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/// Deletes from the local routing table any route for the destination node.
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/// \param [in] dest The destination node address
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/// \return true if the route was present
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bool deleteRouteTo(uint8_t dest);
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/// Deletes the oldest (first) route from the
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/// local routing table
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void retireOldestRoute();
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/// Clears all entries from the
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/// local routing table
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void clearRoutingTable();
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/// If RH_HAVE_SERIAL is defined, this will print out the contents of the local
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/// routing table using Serial
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void printRoutingTable();
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/// Sends a message to the destination node. Initialises the RHRouter message header
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/// (the SOURCE address is set to the address of this node, HOPS to 0) and calls
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/// route() which looks up in the routing table the next hop to deliver to and sends the
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/// message to the next hop. Waits for an acknowledgement from the next hop
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/// (but not from the destination node (if that is different).
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/// \param [in] buf The application message data
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/// \param [in] len Number of octets in the application message data. 0 is permitted
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/// \param [in] dest The destination node address
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/// \param [in] flags Optional flags for use by subclasses or application layer,
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/// delivered end-to-end to the dest address. The receiver can recover the flags with recvFromAck().
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/// \return The result code:
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/// - RH_ROUTER_ERROR_NONE Message was routed and delivered to the next hop
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/// (not necessarily to the final dest address)
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/// - RH_ROUTER_ERROR_NO_ROUTE There was no route for dest in the local routing table
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/// - RH_ROUTER_ERROR_UNABLE_TO_DELIVER Not able to deliver to the next hop
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/// (usually because it dod not acknowledge due to being off the air or out of range
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uint8_t sendtoWait(uint8_t* buf, uint8_t len, uint8_t dest, uint8_t flags = 0);
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/// Similar to sendtoWait() above, but spoofs the source address.
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/// For internal use only during routing
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/// \param [in] buf The application message data.
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/// \param [in] len Number of octets in the application message data. 0 is permitted.
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/// \param [in] dest The destination node address.
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/// \param [in] source The (fake) originating node address.
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/// \param [in] flags Optional flags for use by subclasses or application layer,
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/// delivered end-to-end to the dest address. The receiver can recover the flags with recvFromAck().
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/// \return The result code:
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/// - RH_ROUTER_ERROR_NONE Message was routed and deliverd to the next hop
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/// (not necessarily to the final dest address)
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/// - RH_ROUTER_ERROR_NO_ROUTE There was no route for dest in the local routing table
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/// - RH_ROUTER_ERROR_UNABLE_TO_DELIVER Noyt able to deliver to the next hop
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/// (usually because it dod not acknowledge due to being off the air or out of range
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uint8_t sendtoFromSourceWait(uint8_t* buf, uint8_t len, uint8_t dest, uint8_t source, uint8_t flags = 0);
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/// Starts the receiver if it is not running already.
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/// If there is a valid message available for this node (or RH_BROADCAST_ADDRESS),
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/// send an acknowledgement to the last hop
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/// address (blocking until this is complete), then copy the application message payload data
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/// to buf and return true
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/// else return false.
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/// If a message is copied, *len is set to the length..
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/// If from is not NULL, the originator SOURCE address is placed in *source.
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/// If to is not NULL, the DEST address is placed in *dest. This might be this nodes address or
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/// RH_BROADCAST_ADDRESS.
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/// This is the preferred function for getting messages addressed to this node.
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/// If the message is not a broadcast, acknowledge to the sender before returning.
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/// \param[in] buf Location to copy the received message
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/// \param[in,out] len Available space in buf. Set to the actual number of octets copied.
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/// \param[in] source If present and not NULL, the referenced uint8_t will be set to the SOURCE address
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/// \param[in] dest If present and not NULL, the referenced uint8_t will be set to the DEST address
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/// \param[in] id If present and not NULL, the referenced uint8_t will be set to the ID
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/// \param[in] flags If present and not NULL, the referenced uint8_t will be set to the FLAGS
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/// (not just those addressed to this node).
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/// \return true if a valid message was recvived for this node copied to buf
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bool recvfromAck(uint8_t* buf, uint8_t* len, uint8_t* source = NULL, uint8_t* dest = NULL, uint8_t* id = NULL, uint8_t* flags = NULL);
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/// Starts the receiver if it is not running already.
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/// Similar to recvfromAck(), this will block until either a valid message available for this node
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/// or the timeout expires.
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/// \param[in] buf Location to copy the received message
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/// \param[in,out] len Available space in buf. Set to the actual number of octets copied.
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/// \param[in] timeout Maximum time to wait in milliseconds
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/// \param[in] source If present and not NULL, the referenced uint8_t will be set to the SOURCE address
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/// \param[in] dest If present and not NULL, the referenced uint8_t will be set to the DEST address
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/// \param[in] id If present and not NULL, the referenced uint8_t will be set to the ID
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/// \param[in] flags If present and not NULL, the referenced uint8_t will be set to the FLAGS
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/// (not just those addressed to this node).
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/// \return true if a valid message was copied to buf
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bool recvfromAckTimeout(uint8_t* buf, uint8_t* len, uint16_t timeout, uint8_t* source = NULL, uint8_t* dest = NULL, uint8_t* id = NULL, uint8_t* flags = NULL);
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protected:
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/// Lets sublasses peek at messages going
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/// past before routing or local delivery.
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/// Called by recvfromAck() immediately after it gets the message from RHReliableDatagram
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/// \param [in] message Pointer to the RHRouter message that was received.
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/// \param [in] messageLen Length of message in octets
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virtual void peekAtMessage(RoutedMessage* message, uint8_t messageLen);
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/// Finds the next-hop route and sends the message via RHReliableDatagram::sendtoWait().
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/// This is virtual, which lets subclasses override or intercept the route() function.
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/// Called by sendtoWait after the message header has been filled in.
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/// \param [in] message Pointer to the RHRouter message to be sent.
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/// \param [in] messageLen Length of message in octets
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virtual uint8_t route(RoutedMessage* message, uint8_t messageLen);
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/// Deletes a specific rout entry from therouting table
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/// \param [in] index The 0 based index of the routing table entry to delete
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void deleteRoute(uint8_t index);
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/// The last end-to-end sequence number to be used
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/// Defaults to 0
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uint8_t _lastE2ESequenceNumber;
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/// The maximum number of hops permitted in routed messages.
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/// If a routed message would exceed this number of hops it is dropped and ignored.
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uint8_t _max_hops;
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private:
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/// Temporary mesage buffer
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static RoutedMessage _tmpMessage;
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/// Local routing table
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RoutingTableEntry _routes[RH_ROUTING_TABLE_SIZE];
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};
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/// @example rf22_router_client.pde
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/// @example rf22_router_server1.pde
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/// @example rf22_router_server2.pde
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/// @example rf22_router_server3.pde
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#endif
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