* repeater: new "get/set loop.detect {off | minimal | moderate | strict }"

examples/simple_repeater/MyMesh.cpp

@@ -396,6 +396,23 @@ File MyMesh::openAppend(const char *fname) {
 #endif
 }
 
+static uint8_t max_loop_minimal[] =  { 0, /* 1-byte */  4, /* 2-byte */  2, /* 3-byte */  1 };
+static uint8_t max_loop_moderate[] = { 0, /* 1-byte */  2, /* 2-byte */  1, /* 3-byte */  1 };
+static uint8_t max_loop_strict[] =   { 0, /* 1-byte */  1, /* 2-byte */  1, /* 3-byte */  1 };
+
+bool MyMesh::isLooped(const mesh::Packet* packet, const uint8_t max_counters[]) {
+  uint8_t hash_size = packet->getPathHashSize();
+  uint8_t hash_count = packet->getPathHashCount();
+  uint8_t n = 0;
+  const uint8_t* path = packet->path;
+  while (hash_count > 0) {      // count how many times this node is already in the path
+    if (self_id.isHashMatch(path, hash_size)) n++;
+    hash_count--;
+    path += hash_size;
+  }
+  return n >= max_counters[hash_size];
+}
+
 bool MyMesh::allowPacketForward(const mesh::Packet *packet) {
   if (_prefs.disable_fwd) return false;
   if (packet->isRouteFlood() && packet->getPathHashCount() >= _prefs.flood_max) return false;
@@ -403,6 +420,20 @@ bool MyMesh::allowPacketForward(const mesh::Packet *packet) {
     MESH_DEBUG_PRINTLN("allowPacketForward: unknown transport code, or wildcard not allowed for FLOOD packet");
     return false;
   }
+  if (packet->isRouteFlood() && _prefs.loop_detect != LOOP_DETECT_OFF) {
+    const uint8_t* maximums;
+    if (_prefs.loop_detect == LOOP_DETECT_MINIMAL) {
+      maximums = max_loop_minimal;
+    } else if (_prefs.loop_detect == LOOP_DETECT_MINIMAL) {
+      maximums = max_loop_moderate;
+    } else {
+      maximums = max_loop_strict;
+    }
+    if (isLooped(packet, maximums)) {
+      MESH_DEBUG_PRINTLN("allowPacketForward: FLOOD packet loop detected!");
+      return false;
+    }
+  }
   return true;
 }
 

examples/simple_repeater/MyMesh.h

@@ -128,6 +128,7 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
   mesh::Packet* createSelfAdvert();
 
   File openAppend(const char* fname);
+  bool isLooped(const mesh::Packet* packet, const uint8_t max_counters[]);
 
 protected:
   float getAirtimeBudgetFactor() const override {

src/helpers/CommonCLI.cpp

@@ -64,7 +64,8 @@ void CommonCLI::loadPrefsInt(FILESYSTEM* fs, const char* filename) {
     file.read((uint8_t *)&_prefs->bw, sizeof(_prefs->bw));                                         // 116
     file.read((uint8_t *)&_prefs->agc_reset_interval, sizeof(_prefs->agc_reset_interval));         // 120
     file.read((uint8_t *)&_prefs->path_hash_mode, sizeof(_prefs->path_hash_mode));                 // 121
-    file.read(pad, 2);                                                                             // 122
+    file.read((uint8_t *)&_prefs->loop_detect, sizeof(_prefs->loop_detect));                       // 122
+    file.read(pad, 1);                                                                             // 123
     file.read((uint8_t *)&_prefs->flood_max, sizeof(_prefs->flood_max));                           // 124
     file.read((uint8_t *)&_prefs->flood_advert_interval, sizeof(_prefs->flood_advert_interval));   // 125
     file.read((uint8_t *)&_prefs->interference_threshold, sizeof(_prefs->interference_threshold)); // 126
@@ -150,7 +151,8 @@ void CommonCLI::savePrefs(FILESYSTEM* fs) {
     file.write((uint8_t *)&_prefs->bw, sizeof(_prefs->bw));                                         // 116
     file.write((uint8_t *)&_prefs->agc_reset_interval, sizeof(_prefs->agc_reset_interval));         // 120
     file.write((uint8_t *)&_prefs->path_hash_mode, sizeof(_prefs->path_hash_mode));                 // 121
-    file.write(pad, 2);                                                                             // 122
+    file.write((uint8_t *)&_prefs->loop_detect, sizeof(_prefs->loop_detect));                       // 122
+    file.write(pad, 1);                                                                             // 123
     file.write((uint8_t *)&_prefs->flood_max, sizeof(_prefs->flood_max));                           // 124
     file.write((uint8_t *)&_prefs->flood_advert_interval, sizeof(_prefs->flood_advert_interval));   // 125
     file.write((uint8_t *)&_prefs->interference_threshold, sizeof(_prefs->interference_threshold)); // 126
@@ -334,6 +336,16 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
         *reply = 0;  // set null terminator
       } else if (memcmp(config, "path.hash.mode", 14) == 0) {
         sprintf(reply, "> %d", (uint32_t)_prefs->path_hash_mode);
+      } else if (memcmp(config, "loop.detect", 11) == 0) {
+        if (_prefs->loop_detect == LOOP_DETECT_OFF) {
+          strcpy(reply, "> off");
+        } else if (_prefs->loop_detect == LOOP_DETECT_MINIMAL) {
+          strcpy(reply, "> minimal");
+        } else if (_prefs->loop_detect == LOOP_DETECT_MODERATE) {
+          strcpy(reply, "> moderate");
+        } else {
+          strcpy(reply, "> strict");
+        }
       } else if (memcmp(config, "tx", 2) == 0 && (config[2] == 0 || config[2] == ' ')) {
         sprintf(reply, "> %d", (int32_t) _prefs->tx_power_dbm);
       } else if (memcmp(config, "freq", 4) == 0) {
@@ -575,6 +587,26 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
         } else {
           strcpy(reply, "Error, must be 0,1, or 2");
         }
+      } else if (memcmp(config, "loop.detect ", 12) == 0) {
+        config += 12;
+        uint8_t mode;
+        if (memcmp(config, "off", 3) == 0) {
+          mode = LOOP_DETECT_OFF;
+        } else if (memcmp(config, "minimal", 7) == 0) {
+          mode = LOOP_DETECT_MINIMAL;
+        } else if (memcmp(config, "moderate", 8) == 0) {
+          mode = LOOP_DETECT_MODERATE;
+        } else if (memcmp(config, "strict", 6) == 0) {
+          mode = LOOP_DETECT_STRICT;
+        } else {
+          mode = 0xFF;
+          strcpy(reply, "Error, must be: off, minimal, moderate, or strict");
+        }
+        if (mode != 0xFF) {
+          _prefs->loop_detect = mode;
+          savePrefs();
+          strcpy(reply, "OK");
+        }
       } else if (memcmp(config, "tx ", 3) == 0) {
         _prefs->tx_power_dbm = atoi(&config[3]);
         savePrefs();

src/helpers/CommonCLI.h

@@ -13,6 +13,11 @@
 #define ADVERT_LOC_SHARE      1
 #define ADVERT_LOC_PREFS      2
 
+#define LOOP_DETECT_OFF       0
+#define LOOP_DETECT_MINIMAL   1
+#define LOOP_DETECT_MODERATE  2
+#define LOOP_DETECT_STRICT    3
+
 struct NodePrefs { // persisted to file
   float airtime_factor;
   char node_name[32];
@@ -53,6 +58,7 @@ struct NodePrefs { // persisted to file
   float adc_multiplier;
   char owner_info[120];
   uint8_t path_hash_mode;   // which path mode to use when sending
+  uint8_t loop_detect;
 };
 
 class CommonCLICallbacks {