Make sure next-hop is only set when they received us directly

src/mesh/FloodingRouter.cpp

@@ -102,8 +102,7 @@ void FloodingRouter::perhapsRebroadcast(const meshtastic_MeshPacket *p)
 
                 LOG_INFO("Rebroadcast received floodmsg");
                 // Note: we are careful to resend using the original senders node id
-                // We are careful not to call our hooked version of send() - because we don't want to check this again
+                send(tosend);
-                Router::send(tosend);
             } else {
                 LOG_DEBUG("No rebroadcast: Role = CLIENT_MUTE or Rebroadcast Mode = NONE");
             }

src/mesh/NextHopRouter.cpp

@@ -76,11 +76,14 @@ void NextHopRouter::sniffReceived(const meshtastic_MeshPacket *p, const meshtast
             if (origTx) {
                 // Either relayer of ACK was also a relayer of the packet, or we were the *only* relayer and the ACK came directly
                 // from the destination
-                if (wasRelayer(p->relay_node, p->decoded.request_id, p->to) ||
+                bool wasAlreadyRelayer = wasRelayer(p->relay_node, p->decoded.request_id, p->to);
-                    (p->hop_start != 0 && p->hop_start == p->hop_limit &&
+                bool weWereSoleRelayer = false;
-                     wasSoleRelayer(ourRelayID, p->decoded.request_id, p->to))) {
+                bool weWereRelayer = wasRelayer(ourRelayID, p->decoded.request_id, p->to, &weWereSoleRelayer);
+                if ((weWereRelayer && wasAlreadyRelayer) ||
+                    (p->hop_start != 0 && p->hop_start == p->hop_limit && weWereSoleRelayer)) {
                     if (origTx->next_hop != p->relay_node) { // Not already set
-                        LOG_INFO("Update next hop of 0x%x to 0x%x based on ACK/reply", p->from, p->relay_node);
+                        LOG_INFO("Update next hop of 0x%x to 0x%x based on ACK/reply (was relayer %d we were sole %d)", p->from,
+                                 p->relay_node, wasAlreadyRelayer, weWereSoleRelayer);
                         origTx->next_hop = p->relay_node;
                     }
                 }

src/mesh/PacketHistory.cpp

@@ -66,7 +66,13 @@ bool PacketHistory::wasSeenRecently(const meshtastic_MeshPacket *p, bool withUpd
     r.id = p->id;
     r.sender = getFrom(p); // If 0 then use our ID
     r.next_hop = p->next_hop;
-    r.relayed_by[0] = p->relay_node;
+    bool weWillRelay = false;
+    uint8_t ourRelayID = nodeDB->getLastByteOfNodeNum(nodeDB->getNodeNum());
+    if (p->relay_node == ourRelayID) { // If the relay_node is us, store it
+        weWillRelay = true;
+        r.ourTxHopLimit = p->hop_limit;
+        r.relayed_by[0] = p->relay_node;
+    }
 
     r.rxTimeMsec = millis(); //
     if (r.rxTimeMsec == 0)   // =0 every 49.7 days? 0 is special
@@ -82,8 +88,6 @@ bool PacketHistory::wasSeenRecently(const meshtastic_MeshPacket *p, bool withUpd
     bool seenRecently = (found != NULL);        // If found -> the packet was seen recently
 
     if (seenRecently) {
-        uint8_t ourRelayID = nodeDB->getLastByteOfNodeNum(nodeDB->getNodeNum()); // Get our relay ID from our node number
-
         if (wasFallback) {
             // If it was seen with a next-hop not set to us and now it's NO_NEXT_HOP_PREFERENCE, and the relayer relayed already
             // before, it's a fallback to flooding. If we didn't already relay and the next-hop neither, we might need to handle
@@ -125,11 +129,23 @@ bool PacketHistory::wasSeenRecently(const meshtastic_MeshPacket *p, bool withUpd
                       found->sender, found->id, found->next_hop, found->relayed_by[0], found->relayed_by[1], found->relayed_by[2],
                       millis() - found->rxTimeMsec);
 #endif
+            // Only update the relayer if it heard us directly (meaning hopLimit is decreased by 1)
+            uint8_t startIdx = weWillRelay ? 1 : 0;
+            if (!weWillRelay) {
+                bool weWereRelayer = wasRelayer(ourRelayID, *found);
+                // We were a relayer and the packet came in with a hop limit that is one less than when we sent it out
+                if (weWereRelayer && p->hop_limit == found->ourTxHopLimit - 1) {
+                    r.relayed_by[0] = p->relay_node;
+                    startIdx = 1; // Start copying existing relayers from index 1
+                }
+                // keep the original ourTxHopLimit
+                r.ourTxHopLimit = found->ourTxHopLimit;
+            }
 
             // Add the existing relayed_by to the new record
             for (uint8_t i = 0; i < (NUM_RELAYERS - 1); i++) {
                 if (found->relayed_by[i] != 0)
-                    r.relayed_by[i + 1] = found->relayed_by[i];
+                    r.relayed_by[i + startIdx] = found->relayed_by[i];
             }
             r.next_hop = found->next_hop; // keep the original next_hop (such that we check whether we were originally asked)
 #if VERBOSE_PACKET_HISTORY
@@ -352,14 +368,6 @@ bool PacketHistory::wasRelayer(const uint8_t relayer, const PacketRecord &r, boo
     return found;
 }
 
-// Check if a certain node was the *only* relayer of a packet in the history given an ID and sender
-bool PacketHistory::wasSoleRelayer(const uint8_t relayer, const uint32_t id, const NodeNum sender)
-{
-    bool wasSole = false;
-    wasRelayer(relayer, id, sender, &wasSole);
-    return wasSole;
-}
-
 // Remove a relayer from the list of relayers of a packet in the history given an ID and sender
 void PacketHistory::removeRelayer(const uint8_t relayer, const uint32_t id, const NodeNum sender)
 {

src/mesh/PacketHistory.h

@@ -2,8 +2,8 @@
 
 #include "NodeDB.h"
 
-#define NUM_RELAYERS                                                                                                             \
+// Number of relayers we keep track of. Use 6 to be efficient with memory alignment of PacketRecord to 20 bytes
-    3 // Number of relayer we keep track of. Use 3 to be efficient with memory alignment of PacketRecord to 16 bytes
+#define NUM_RELAYERS 6
 
 /**
  * This is a mixin that adds a record of past packets we have seen
@@ -16,8 +16,9 @@ class PacketHistory
         PacketId id;
         uint32_t rxTimeMsec;              // Unix time in msecs - the time we received it,  0 means empty
         uint8_t next_hop;                 // The next hop asked for this packet
+        uint8_t ourTxHopLimit;            // The hop limit of the packet when we first transmitted it
         uint8_t relayed_by[NUM_RELAYERS]; // Array of nodes that relayed this packet
-    };                                    // 4B + 4B + 4B + 1B + 3B = 16B
+    };                                    // 4B + 4B + 4B + 1B + 1B + 6B = 20B
 
     uint32_t recentPacketsCapacity =
         0; // Can be set in constructor, no need to recompile. Used to allocate memory for mx_recentPackets.
@@ -59,9 +60,6 @@ class PacketHistory
      * @return true if node was indeed a relayer, false if not */
     bool wasRelayer(const uint8_t relayer, const uint32_t id, const NodeNum sender, bool *wasSole = nullptr);
 
-    // Check if a certain node was the *only* relayer of a packet in the history given an ID and sender
-    bool wasSoleRelayer(const uint8_t relayer, const uint32_t id, const NodeNum sender);
-
     // Remove a relayer from the list of relayers of a packet in the history given an ID and sender
     void removeRelayer(const uint8_t relayer, const uint32_t id, const NodeNum sender);