Initial version of NextHopRouter

src/mesh/NextHopRouter.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include "FloodingRouter.h"
+
+/*
+  Router which only relays if it is the next hop for a packet.
+  The next hop is set by the current relayer of a packet, which bases this on information from either the NeighborInfoModule, or a
+  previous successful delivery via flooding. It is only used for DMs and not used for broadcasts. Using the NeighborInfoModule, it
+  can derive the next hop of neighbors and that of neighbors of neighbors. For others, it has no information in the beginning,
+  which results into falling back to the FloodingRouter. Upon successful delivery via flooding, it updates the next hop of the
+  recipient to the node that last relayed the ACK to us. When the ReliableRouter is doing retransmissions, at the last retry, it
+  will reset the next hop, in order to fall back to the FloodingRouter.
+*/
+class NextHopRouter : public FloodingRouter
+{
+  public:
+    /**
+     * Constructor
+     *
+     */
+    NextHopRouter();
+
+    /**
+     * Send a packet
+     * @return an error code
+     */
+    virtual ErrorCode send(meshtastic_MeshPacket *p) override;
+
+  protected:
+    /**
+     * Should this incoming filter be dropped?
+     *
+     * Called immediately on reception, before any further processing.
+     * @return true to abandon the packet
+     */
+    virtual bool shouldFilterReceived(const meshtastic_MeshPacket *p) override;
+
+    /**
+     * Look for packets we need to relay
+     */
+    virtual void sniffReceived(const meshtastic_MeshPacket *p, const meshtastic_Routing *c) override;
+
+  private:
+    /**
+     * Get the next hop for a destination, given the current relayer
+     * @return the node number of the next hop, 0 if no preference (fallback to FloodingRouter)
+     */
+    uint32_t getNextHop(NodeNum to, NodeNum current_relayer);
+};