From 63c8f15d387b724bdcfb33d277d401e81ba6a73e Mon Sep 17 00:00:00 2001
From: GUVWAF <78759985+GUVWAF@users.noreply.github.com>
Date: Sat, 13 Aug 2022 17:09:43 +0200
Subject: [PATCH] Resend implicit ACK for a repeated broadcast (#1628)

---
 src/mesh/ReliableRouter.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/mesh/ReliableRouter.cpp b/src/mesh/ReliableRouter.cpp
index 9a65823e..51078283 100644
--- a/src/mesh/ReliableRouter.cpp
+++ b/src/mesh/ReliableRouter.cpp
@@ -67,6 +67,12 @@ bool ReliableRouter::shouldFilterReceived(MeshPacket *p)
             sendAckNak(Routing_Error_NONE, getFrom(p), p->id, p->channel);
             DEBUG_MSG("acking a repeated want_ack packet\n");
         }
+    } else if (wasSeenRecently(p, false) && p->hop_limit == HOP_RELIABLE) {
+        // retransmission on broadcast has hop_limit still equal to HOP_RELIABLE
+        DEBUG_MSG("Resending implicit ack for a repeated floodmsg\n");
+        MeshPacket *tosend = packetPool.allocCopy(*p);
+        tosend->hop_limit--; // bump down the hop count
+        Router::send(tosend);
     }
 
     return FloodingRouter::shouldFilterReceived(p);