From 7dee23fa0d943e50c51c28a1a4db561ad3ac3806 Mon Sep 17 00:00:00 2001
From: Jukka Vaisanen <vaizki@vaizki.fi>
Date: Wed, 10 Jun 2026 18:07:44 +0300
Subject: [PATCH] ignore leading zero path padding for flood max

---
 examples/simple_repeater/MyMesh.cpp    |  7 ++++---
 examples/simple_room_server/MyMesh.cpp |  7 ++++---
 examples/simple_sensor/SensorMesh.cpp  |  2 +-
 src/Packet.cpp                         | 18 +++++++++++++++++-
 src/Packet.h                           |  1 +
 5 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/examples/simple_repeater/MyMesh.cpp b/examples/simple_repeater/MyMesh.cpp
index 096907494b..c73e5608f4 100644
--- a/examples/simple_repeater/MyMesh.cpp
+++ b/examples/simple_repeater/MyMesh.cpp
@@ -429,9 +429,10 @@ void MyMesh::sendFloodReply(mesh::Packet* packet, unsigned long delay_millis, ui
 bool MyMesh::allowPacketForward(const mesh::Packet *packet) {
   if (_prefs.disable_fwd) return false;
   if (packet->isRouteFlood()) {
-    if (packet->getPathHashCount() >= _prefs.flood_max) return false;
-    if (packet->getRouteType() == ROUTE_TYPE_FLOOD && packet->getPathHashCount() >= _prefs.flood_max_unscoped) return false;
-    if (packet->getPayloadType() == PAYLOAD_TYPE_ADVERT && packet->getPathHashCount() >= _prefs.flood_max_advert) return false;
+    uint8_t flood_hops = packet->getPathHashCountExcludingLeadingZeros();
+    if (flood_hops >= _prefs.flood_max) return false;
+    if (packet->getRouteType() == ROUTE_TYPE_FLOOD && flood_hops >= _prefs.flood_max_unscoped) return false;
+    if (packet->getPayloadType() == PAYLOAD_TYPE_ADVERT && flood_hops >= _prefs.flood_max_advert) return false;
   }
   if (packet->isRouteFlood() && recv_pkt_region == NULL) {
     MESH_DEBUG_PRINTLN("allowPacketForward: unknown transport code, or wildcard not allowed for FLOOD packet");
diff --git a/examples/simple_room_server/MyMesh.cpp b/examples/simple_room_server/MyMesh.cpp
index 98b22fdb72..2c2ac51306 100644
--- a/examples/simple_room_server/MyMesh.cpp
+++ b/examples/simple_room_server/MyMesh.cpp
@@ -283,9 +283,10 @@ uint32_t MyMesh::getDirectRetransmitDelay(const mesh::Packet *packet) {
 bool MyMesh::allowPacketForward(const mesh::Packet *packet) {
   if (_prefs.disable_fwd) return false;
   if (packet->isRouteFlood()) {
-    if (packet->getPathHashCount() >= _prefs.flood_max) return false;
-    if (packet->getRouteType() == ROUTE_TYPE_FLOOD && packet->getPathHashCount() >= _prefs.flood_max_unscoped) return false;
-    if (packet->getPayloadType() == PAYLOAD_TYPE_ADVERT && packet->getPathHashCount() >= _prefs.flood_max_advert) return false;
+    uint8_t flood_hops = packet->getPathHashCountExcludingLeadingZeros();
+    if (flood_hops >= _prefs.flood_max) return false;
+    if (packet->getRouteType() == ROUTE_TYPE_FLOOD && flood_hops >= _prefs.flood_max_unscoped) return false;
+    if (packet->getPayloadType() == PAYLOAD_TYPE_ADVERT && flood_hops >= _prefs.flood_max_advert) return false;
   }
   return true;
 }
diff --git a/examples/simple_sensor/SensorMesh.cpp b/examples/simple_sensor/SensorMesh.cpp
index 879fcbf026..e418b9cb61 100644
--- a/examples/simple_sensor/SensorMesh.cpp
+++ b/examples/simple_sensor/SensorMesh.cpp
@@ -303,7 +303,7 @@ float SensorMesh::getAirtimeBudgetFactor() const {
 
 bool SensorMesh::allowPacketForward(const mesh::Packet* packet) {
   if (_prefs.disable_fwd) return false;
-  if (packet->isRouteFlood() && packet->getPathHashCount() >= _prefs.flood_max) return false;
+  if (packet->isRouteFlood() && packet->getPathHashCountExcludingLeadingZeros() >= _prefs.flood_max) return false;
   return true;
 }
 
diff --git a/src/Packet.cpp b/src/Packet.cpp
index aad3e2f48e..09ac4ecc97 100644
--- a/src/Packet.cpp
+++ b/src/Packet.cpp
@@ -34,6 +34,22 @@ uint8_t Packet::copyPath(uint8_t* dest, const uint8_t* src, uint8_t path_len) {
   return path_len;
 }
 
+uint8_t Packet::getPathHashCountExcludingLeadingZeros() const {
+  uint8_t hash_count = getPathHashCount();
+  uint8_t hash_size = getPathHashSize();
+  if (hash_size > 3) return hash_count;
+  if (hash_count == 0 || path[0] != 0) return hash_count;
+
+  uint8_t path_byte_len = hash_count * hash_size;
+  uint8_t zero_bytes = 1;
+  while (zero_bytes < path_byte_len && path[zero_bytes] == 0) {
+    zero_bytes++;
+  }
+
+  uint8_t padding_count = zero_bytes / hash_size;
+  return hash_count - padding_count;
+}
+
 int Packet::getRawLength() const {
   return 2 + getPathByteLen() + payload_len + (hasTransportCodes() ? 4 : 0);
 }
@@ -84,4 +100,4 @@ bool Packet::readFrom(const uint8_t src[], uint8_t len) {
   return true;   // success
 }
 
-}
\ No newline at end of file
+}
diff --git a/src/Packet.h b/src/Packet.h
index 0886a06c4e..3cd384d777 100644
--- a/src/Packet.h
+++ b/src/Packet.h
@@ -78,6 +78,7 @@ class Packet {
 
   uint8_t getPathHashSize() const { return (path_len >> 6) + 1; }
   uint8_t getPathHashCount() const { return path_len & 63; }
+  uint8_t getPathHashCountExcludingLeadingZeros() const;
   uint8_t getPathByteLen() const { return getPathHashCount() * getPathHashSize(); }
   void setPathHashCount(uint8_t n) { path_len &= ~63; path_len |= n; }
   void setPathHashSizeAndCount(uint8_t sz, uint8_t n) { path_len = ((sz - 1) << 6) | (n & 63); }