* refactor of Contact/Client out_path_len (stored in files), from signed to unsigned byte (+2 squashed commits)

Squashed commits:
[f326e25] * misc
[fa5152e] * new 'path mode' parsing in Dispatcher

examples/companion_radio/MyMesh.cpp

@@ -258,11 +258,11 @@ int MyMesh::calcRxDelay(float score, uint32_t air_time) const {
 }
 
 uint32_t MyMesh::getRetransmitDelay(const mesh::Packet *packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * 0.5f);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * 0.5f);
   return getRNG()->nextInt(0, 5*t + 1);
 }
 uint32_t MyMesh::getDirectRetransmitDelay(const mesh::Packet *packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * 0.2f);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * 0.2f);
   return getRNG()->nextInt(0, 5*t + 1);
 }
 
@@ -678,7 +678,7 @@ void MyMesh::onContactResponse(const ContactInfo &contact, const uint8_t *data,
   }
 }
 
-bool MyMesh::onContactPathRecv(ContactInfo& contact, uint8_t* in_path, uint8_t in_path_len, uint8_t* out_path, uint8_t out_path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) {
+bool MyMesh::onContactPathRecv(ContactInfo& contact, uint8_t* in_path, uint8_t _in_path_len, uint8_t* out_path, uint8_t _out_path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) {
   if (extra_type == PAYLOAD_TYPE_RESPONSE && extra_len > 4) {
     uint32_t tag;
     memcpy(&tag, extra, 4);
@@ -785,9 +785,10 @@ uint32_t MyMesh::calcFloodTimeoutMillisFor(uint32_t pkt_airtime_millis) const {
   return SEND_TIMEOUT_BASE_MILLIS + (FLOOD_SEND_TIMEOUT_FACTOR * pkt_airtime_millis);
 }
 uint32_t MyMesh::calcDirectTimeoutMillisFor(uint32_t pkt_airtime_millis, uint8_t path_len) const {
+  uint8_t path_hash_count = path_len & 63;
   return SEND_TIMEOUT_BASE_MILLIS +
          ((pkt_airtime_millis * DIRECT_SEND_PERHOP_FACTOR + DIRECT_SEND_PERHOP_EXTRA_MILLIS) *
-          (path_len + 1));
+          (path_hash_count + 1));
 }
 
 void MyMesh::onSendTimeout() {}
@@ -1115,7 +1116,7 @@ void MyMesh::handleCmdFrame(size_t len) {
     }
     if (pkt) {
       if (len >= 2 && cmd_frame[1] == 1) { // optional param (1 = flood, 0 = zero hop)
-        sendFlood(pkt);
+        sendFlood(pkt);  // TODO: which path_hash_size to use??
       } else {
         sendZeroHop(pkt);
       }
@@ -1127,7 +1128,7 @@ void MyMesh::handleCmdFrame(size_t len) {
     uint8_t *pub_key = &cmd_frame[1];
     ContactInfo *recipient = lookupContactByPubKey(pub_key, PUB_KEY_SIZE);
     if (recipient) {
-      recipient->out_path_len = -1;
+      recipient->out_path_len = OUT_PATH_UNKNOWN;
       // recipient->lastmod = ??   shouldn't be needed, app already has this version of contact
       dirty_contacts_expiry = futureMillis(LAZY_CONTACTS_WRITE_DELAY);
       writeOKFrame();
@@ -1449,7 +1450,7 @@ void MyMesh::handleCmdFrame(size_t len) {
       memset(&req_data[2], 0, 3);  // reserved
       getRNG()->random(&req_data[5], 4);   // random blob to help make packet-hash unique
       auto save = recipient->out_path_len;    // temporarily force sendRequest() to flood
-      recipient->out_path_len = -1;
+      recipient->out_path_len = OUT_PATH_UNKNOWN;
       int result = sendRequest(*recipient, req_data, sizeof(req_data), tag, est_timeout);
       recipient->out_path_len = save;
       if (result == MSG_SEND_FAILED) {

examples/simple_repeater/MyMesh.cpp

@@ -129,7 +129,7 @@ uint8_t MyMesh::handleLoginReq(const mesh::Identity& sender, const uint8_t* secr
   }
 
   if (is_flood) {
-    client->out_path_len = -1;  // need to rediscover out_path
+    client->out_path_len = OUT_PATH_UNKNOWN;  // need to rediscover out_path
   }
 
   uint32_t now = getRTCClock()->getCurrentTimeUnique();
@@ -147,9 +147,12 @@ uint8_t MyMesh::handleLoginReq(const mesh::Identity& sender, const uint8_t* secr
 uint8_t MyMesh::handleAnonRegionsReq(const mesh::Identity& sender, uint32_t sender_timestamp, const uint8_t* data) {
   if (anon_limiter.allow(rtc_clock.getCurrentTime())) {
     // request data has: {reply-path-len}{reply-path}
-    reply_path_len = *data++ & 0x3F;
-    memcpy(reply_path, data, reply_path_len);
-    // data += reply_path_len;
+    reply_path_len = *data & 63;
+    reply_path_hash_size = (*data >> 6) + 1;
+    data++;
+
+    memcpy(reply_path, data, ((uint8_t)reply_path_len) * reply_path_hash_size);
+    // data += (uint8_t)reply_path_len * reply_path_hash_size;
 
     memcpy(reply_data, &sender_timestamp, 4);   // prefix with sender_timestamp, like a tag
     uint32_t now = getRTCClock()->getCurrentTime();
@@ -163,9 +166,12 @@ uint8_t MyMesh::handleAnonRegionsReq(const mesh::Identity& sender, uint32_t send
 uint8_t MyMesh::handleAnonOwnerReq(const mesh::Identity& sender, uint32_t sender_timestamp, const uint8_t* data) {
   if (anon_limiter.allow(rtc_clock.getCurrentTime())) {
     // request data has: {reply-path-len}{reply-path}
-    reply_path_len = *data++ & 0x3F;
-    memcpy(reply_path, data, reply_path_len);
-    // data += reply_path_len;
+    reply_path_len = *data & 63;
+    reply_path_hash_size = (*data >> 6) + 1;
+    data++;
+
+    memcpy(reply_path, data, ((uint8_t)reply_path_len) * reply_path_hash_size);
+    // data += (uint8_t)reply_path_len * reply_path_hash_size;
 
     memcpy(reply_data, &sender_timestamp, 4);   // prefix with sender_timestamp, like a tag
     uint32_t now = getRTCClock()->getCurrentTime();
@@ -180,9 +186,12 @@ uint8_t MyMesh::handleAnonOwnerReq(const mesh::Identity& sender, uint32_t sender
 uint8_t MyMesh::handleAnonClockReq(const mesh::Identity& sender, uint32_t sender_timestamp, const uint8_t* data) {
   if (anon_limiter.allow(rtc_clock.getCurrentTime())) {
     // request data has: {reply-path-len}{reply-path}
-    reply_path_len = *data++ & 0x3F;
-    memcpy(reply_path, data, reply_path_len);
-    // data += reply_path_len;
+    reply_path_len = *data & 63;
+    reply_path_hash_size = (*data >> 6) + 1;
+    data++;
+
+    memcpy(reply_path, data, ((uint8_t)reply_path_len) * reply_path_hash_size);
+    // data += (uint8_t)reply_path_len * reply_path_hash_size;
 
     memcpy(reply_data, &sender_timestamp, 4);   // prefix with sender_timestamp, like a tag
     uint32_t now = getRTCClock()->getCurrentTime();
@@ -389,7 +398,7 @@ File MyMesh::openAppend(const char *fname) {
 
 bool MyMesh::allowPacketForward(const mesh::Packet *packet) {
   if (_prefs.disable_fwd) return false;
-  if (packet->isRouteFlood() && packet->path_len >= _prefs.flood_max) return false;
+  if (packet->isRouteFlood() && packet->getPathHashCount() >= _prefs.flood_max) return false;
   if (packet->isRouteFlood() && recv_pkt_region == NULL) {
     MESH_DEBUG_PRINTLN("allowPacketForward: unknown transport code, or wildcard not allowed for FLOOD packet");
     return false;
@@ -484,11 +493,11 @@ int MyMesh::calcRxDelay(float score, uint32_t air_time) const {
 }
 
 uint32_t MyMesh::getRetransmitDelay(const mesh::Packet *packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.tx_delay_factor);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * _prefs.tx_delay_factor);
   return getRNG()->nextInt(0, 5*t + 1);
 }
 uint32_t MyMesh::getDirectRetransmitDelay(const mesh::Packet *packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
   return getRNG()->nextInt(0, 5*t + 1);
 }
 
@@ -538,13 +547,14 @@ void MyMesh::onAnonDataRecv(mesh::Packet *packet, const uint8_t *secret, const m
       // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
       mesh::Packet* path = createPathReturn(sender, secret, packet->path, packet->path_len,
                                             PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
-      if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
+      if (path) sendFlood(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
     } else if (reply_path_len < 0) {
       mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, secret, reply_data, reply_len);
-      if (reply) sendFlood(reply, SERVER_RESPONSE_DELAY);
+      if (reply) sendFlood(reply, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
     } else {
       mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, secret, reply_data, reply_len);
-      if (reply) sendDirect(reply, reply_path, reply_path_len, SERVER_RESPONSE_DELAY);
+      uint8_t path_len = ((reply_path_hash_size - 1) << 6) | (reply_path_len & 63);
+      if (reply) sendDirect(reply, reply_path,  path_len, SERVER_RESPONSE_DELAY);
     }
   }
 }
@@ -613,15 +623,15 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
         // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
         mesh::Packet *path = createPathReturn(client->id, secret, packet->path, packet->path_len,
                                               PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
-        if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
+        if (path) sendFlood(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
       } else {
         mesh::Packet *reply =
             createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, secret, reply_data, reply_len);
         if (reply) {
-          if (client->out_path_len >= 0) { // we have an out_path, so send DIRECT
+          if (client->out_path_len != OUT_PATH_UNKNOWN) { // we have an out_path, so send DIRECT
             sendDirect(reply, client->out_path, client->out_path_len, SERVER_RESPONSE_DELAY);
           } else {
-            sendFlood(reply, SERVER_RESPONSE_DELAY);
+            sendFlood(reply, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
           }
         }
       }
@@ -651,8 +661,8 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
 
         mesh::Packet *ack = createAck(ack_hash);
         if (ack) {
-          if (client->out_path_len < 0) {
-            sendFlood(ack, TXT_ACK_DELAY);
+          if (client->out_path_len == OUT_PATH_UNKNOWN) {
+            sendFlood(ack, TXT_ACK_DELAY, packet->getPathHashSize());
           } else {
             sendDirect(ack, client->out_path, client->out_path_len, TXT_ACK_DELAY);
           }
@@ -679,8 +689,8 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
 
         auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len);
         if (reply) {
-          if (client->out_path_len < 0) {
-            sendFlood(reply, CLI_REPLY_DELAY_MILLIS);
+          if (client->out_path_len == OUT_PATH_UNKNOWN) {
+            sendFlood(reply, CLI_REPLY_DELAY_MILLIS, packet->getPathHashSize());
           } else {
             sendDirect(reply, client->out_path, client->out_path_len, CLI_REPLY_DELAY_MILLIS);
           }
@@ -701,7 +711,8 @@ bool MyMesh::onPeerPathRecv(mesh::Packet *packet, int sender_idx, const uint8_t
     MESH_DEBUG_PRINTLN("PATH to client, path_len=%d", (uint32_t)path_len);
     auto client = acl.getClientByIdx(i);
 
-    memcpy(client->out_path, path, client->out_path_len = path_len); // store a copy of path, for sendDirect()
+    // store a copy of path, for sendDirect()
+    client->out_path_len = mesh::Packet::copyPath(client->out_path, path, path_len);
     client->last_activity = getRTCClock()->getCurrentTime();
   } else {
     MESH_DEBUG_PRINTLN("onPeerPathRecv: invalid peer idx: %d", i);
@@ -906,7 +917,7 @@ void MyMesh::sendSelfAdvertisement(int delay_millis, bool flood) {
   mesh::Packet *pkt = createSelfAdvert();
   if (pkt) {
     if (flood) {
-      sendFlood(pkt, delay_millis);
+      sendFlood(pkt, delay_millis);   // TODO: which path_hash_size to use??
     } else {
       sendZeroHop(pkt, delay_millis);
     }

examples/simple_repeater/MyMesh.h

@@ -92,6 +92,7 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
   uint8_t reply_data[MAX_PACKET_PAYLOAD];
   uint8_t reply_path[MAX_PATH_SIZE];
   int8_t  reply_path_len;
+  uint8_t reply_path_hash_size;
   TransportKeyStore key_store;
   RegionMap region_map, temp_map;
   RegionEntry* load_stack[8];

examples/simple_room_server/MyMesh.cpp

@@ -73,13 +73,14 @@ void MyMesh::pushPostToClient(ClientInfo *client, PostInfo &post) {
 
   auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, client->shared_secret, reply_data, len);
   if (reply) {
-    if (client->out_path_len < 0) {
-      sendFlood(reply);
+    if (client->out_path_len == OUT_PATH_UNKNOWN) {
+      sendFlood(reply);  // TODO: which path_hash_size to use?
       client->extra.room.ack_timeout = futureMillis(PUSH_ACK_TIMEOUT_FLOOD);
     } else {
       sendDirect(reply, client->out_path, client->out_path_len);
-      client->extra.room.ack_timeout =
-          futureMillis(PUSH_TIMEOUT_BASE + PUSH_ACK_TIMEOUT_FACTOR * (client->out_path_len + 1));
+
+      uint8_t path_hash_count = client->out_path_len & 63;
+      client->extra.room.ack_timeout = futureMillis(PUSH_TIMEOUT_BASE + PUSH_ACK_TIMEOUT_FACTOR * (path_hash_count + 1));
     }
     _num_post_pushes++; // stats
   } else {
@@ -264,17 +265,17 @@ const char *MyMesh::getLogDateTime() {
 }
 
 uint32_t MyMesh::getRetransmitDelay(const mesh::Packet *packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.tx_delay_factor);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * _prefs.tx_delay_factor);
   return getRNG()->nextInt(0, 5*t + 1);
 }
 uint32_t MyMesh::getDirectRetransmitDelay(const mesh::Packet *packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
   return getRNG()->nextInt(0, 5*t + 1);
 }
 
 bool MyMesh::allowPacketForward(const mesh::Packet *packet) {
   if (_prefs.disable_fwd) return false;
-  if (packet->isRouteFlood() && packet->path_len >= _prefs.flood_max) return false;
+  if (packet->isRouteFlood() && packet->getPathHashCount() >= _prefs.flood_max) return false;
   return true;
 }
 
@@ -333,7 +334,7 @@ void MyMesh::onAnonDataRecv(mesh::Packet *packet, const uint8_t *secret, const m
     }
 
     if (packet->isRouteFlood()) {
-      client->out_path_len = -1;  // need to rediscover out_path
+      client->out_path_len = OUT_PATH_UNKNOWN;  // need to rediscover out_path
     }
 
     uint32_t now = getRTCClock()->getCurrentTimeUnique();
@@ -353,14 +354,14 @@ void MyMesh::onAnonDataRecv(mesh::Packet *packet, const uint8_t *secret, const m
       // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
       mesh::Packet *path = createPathReturn(sender, client->shared_secret, packet->path, packet->path_len,
                                             PAYLOAD_TYPE_RESPONSE, reply_data, 13);
-      if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
+      if (path) sendFlood(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
     } else {
       mesh::Packet *reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, client->shared_secret, reply_data, 13);
       if (reply) {
-        if (client->out_path_len >= 0) { // we have an out_path, so send DIRECT
+        if (client->out_path_len != OUT_PATH_UNKNOWN) { // we have an out_path, so send DIRECT
           sendDirect(reply, client->out_path, client->out_path_len, SERVER_RESPONSE_DELAY);
         } else {
-          sendFlood(reply, SERVER_RESPONSE_DELAY);
+          sendFlood(reply, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
         }
       }
     }
@@ -448,9 +449,9 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
 
       uint32_t delay_millis;
       if (send_ack) {
-        if (client->out_path_len < 0) {
+        if (client->out_path_len == OUT_PATH_UNKNOWN) {
           mesh::Packet *ack = createAck(ack_hash);
-          if (ack) sendFlood(ack, TXT_ACK_DELAY);
+          if (ack) sendFlood(ack, TXT_ACK_DELAY, packet->getPathHashSize());
           delay_millis = TXT_ACK_DELAY + REPLY_DELAY_MILLIS;
         } else {
           uint32_t d = TXT_ACK_DELAY;
@@ -482,8 +483,8 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
 
         auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len);
         if (reply) {
-          if (client->out_path_len < 0) {
-            sendFlood(reply, delay_millis + SERVER_RESPONSE_DELAY);
+          if (client->out_path_len == OUT_PATH_UNKNOWN) {
+            sendFlood(reply, delay_millis + SERVER_RESPONSE_DELAY, packet->getPathHashSize());
           } else {
             sendDirect(reply, client->out_path, client->out_path_len, delay_millis + SERVER_RESPONSE_DELAY);
           }
@@ -521,7 +522,7 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
         // if client sends too quickly, evict()
 
         // RULE: only send keep_alive response DIRECT!
-        if (client->out_path_len >= 0) {
+        if (client->out_path_len != OUT_PATH_UNKNOWN) {
           uint32_t ack_hash; // calc ACK to prove to sender that we got request
           mesh::Utils::sha256((uint8_t *)&ack_hash, 4, data, 9, client->id.pub_key, PUB_KEY_SIZE);
 
@@ -538,14 +539,14 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
             // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
             mesh::Packet *path = createPathReturn(client->id, secret, packet->path, packet->path_len,
                                                   PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
-            if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
+            if (path) sendFlood(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
           } else {
             mesh::Packet *reply = createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, secret, reply_data, reply_len);
             if (reply) {
-              if (client->out_path_len >= 0) { // we have an out_path, so send DIRECT
+              if (client->out_path_len != OUT_PATH_UNKNOWN) { // we have an out_path, so send DIRECT
                 sendDirect(reply, client->out_path, client->out_path_len, SERVER_RESPONSE_DELAY);
               } else {
-                sendFlood(reply, SERVER_RESPONSE_DELAY);
+                sendFlood(reply, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
               }
             }
           }
@@ -563,7 +564,7 @@ bool MyMesh::onPeerPathRecv(mesh::Packet *packet, int sender_idx, const uint8_t
   if (i >= 0 && i < acl.getNumClients()) { // get from our known_clients table (sender SHOULD already be known in this context)
     MESH_DEBUG_PRINTLN("PATH to client, path_len=%d", (uint32_t)path_len);
     auto client = acl.getClientByIdx(i);
-    memcpy(client->out_path, path, client->out_path_len = path_len); // store a copy of path, for sendDirect()
+    client->out_path_len = mesh::Packet::copyPath(client->out_path, path, path_len); // store a copy of path, for sendDirect()
     client->last_activity = getRTCClock()->getCurrentTime();
   } else {
     MESH_DEBUG_PRINTLN("onPeerPathRecv: invalid peer idx: %d", i);
@@ -679,7 +680,7 @@ void MyMesh::sendSelfAdvertisement(int delay_millis, bool flood) {
   mesh::Packet *pkt = createSelfAdvert();
   if (pkt) {
     if (flood) {
-      sendFlood(pkt, delay_millis);
+      sendFlood(pkt, delay_millis);  // TODO: which path_hash_size to use?
     } else {
       sendZeroHop(pkt, delay_millis);
     }

examples/simple_secure_chat/main.cpp

@@ -213,7 +213,7 @@ protected:
   }
 
   void onContactPathUpdated(const ContactInfo& contact) override {
-    Serial.printf("PATH to: %s, path_len=%d\n", contact.name, (int32_t) contact.out_path_len);
+    Serial.printf("PATH to: %s, path_len=%d\n", contact.name, (uint32_t) contact.out_path_len);
     saveContacts();
   }
 
@@ -266,8 +266,9 @@ protected:
     return SEND_TIMEOUT_BASE_MILLIS + (FLOOD_SEND_TIMEOUT_FACTOR * pkt_airtime_millis);
   }
   uint32_t calcDirectTimeoutMillisFor(uint32_t pkt_airtime_millis, uint8_t path_len) const override {
+    uint8_t path_hash_count = path_len & 63;
     return SEND_TIMEOUT_BASE_MILLIS + 
-         ( (pkt_airtime_millis*DIRECT_SEND_PERHOP_FACTOR + DIRECT_SEND_PERHOP_EXTRA_MILLIS) * (path_len + 1));
+         ( (pkt_airtime_millis*DIRECT_SEND_PERHOP_FACTOR + DIRECT_SEND_PERHOP_EXTRA_MILLIS) * (path_hash_count + 1));
   }
 
   void onSendTimeout() override {

examples/simple_sensor/SensorMesh.cpp

@@ -258,7 +258,7 @@ void SensorMesh::sendAlert(const ClientInfo* c, Trigger* t) {
 
   auto pkt = createDatagram(PAYLOAD_TYPE_TXT_MSG, c->id, c->shared_secret, data, 5 + text_len);
   if (pkt) {
-    if (c->out_path_len >= 0) {  // we have an out_path, so send DIRECT
+    if (c->out_path_len != OUT_PATH_UNKNOWN) {  // we have an out_path, so send DIRECT
       sendDirect(pkt, c->out_path, c->out_path_len);
     } else {
       sendFlood(pkt);
@@ -302,7 +302,7 @@ float SensorMesh::getAirtimeBudgetFactor() const {
 
 bool SensorMesh::allowPacketForward(const mesh::Packet* packet) {
   if (_prefs.disable_fwd) return false;
-  if (packet->isRouteFlood() && packet->path_len >= _prefs.flood_max) return false;
+  if (packet->isRouteFlood() && packet->getPathHashCount() >= _prefs.flood_max) return false;
   return true;
 }
 
@@ -312,11 +312,11 @@ int SensorMesh::calcRxDelay(float score, uint32_t air_time) const {
 }
 
 uint32_t SensorMesh::getRetransmitDelay(const mesh::Packet* packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.tx_delay_factor);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * _prefs.tx_delay_factor);
   return getRNG()->nextInt(0, 6)*t;
 }
 uint32_t SensorMesh::getDirectRetransmitDelay(const mesh::Packet* packet) {
-  uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
+  uint32_t t = (_radio->getEstAirtimeFor(packet->getPathByteLen() + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
   return getRNG()->nextInt(0, 6)*t;
 }
 int SensorMesh::getInterferenceThreshold() const {
@@ -360,7 +360,7 @@ uint8_t SensorMesh::handleLoginReq(const mesh::Identity& sender, const uint8_t*
   }
 
   if (is_flood) {
-    client->out_path_len = -1;  // need to rediscover out_path
+    client->out_path_len = OUT_PATH_UNKNOWN;  // need to rediscover out_path
   }
 
   uint32_t now = getRTCClock()->getCurrentTimeUnique();
@@ -468,10 +468,10 @@ void SensorMesh::onAnonDataRecv(mesh::Packet* packet, const uint8_t* secret, con
       // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
       mesh::Packet* path = createPathReturn(sender, secret, packet->path, packet->path_len,
                                             PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
-      if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
+      if (path) sendFlood(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
     } else {
       mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, secret, reply_data, reply_len);
-      if (reply) sendFlood(reply, SERVER_RESPONSE_DELAY);
+      if (reply) sendFlood(reply, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
     }
   }
 }
@@ -496,10 +496,10 @@ void SensorMesh::getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) {
   }
 }
 
-void SensorMesh::sendAckTo(const ClientInfo& dest, uint32_t ack_hash) {
-  if (dest.out_path_len < 0) {
+void SensorMesh::sendAckTo(const ClientInfo& dest, uint32_t ack_hash, uint8_t path_hash_size) {
+  if (dest.out_path_len == OUT_PATH_UNKNOWN) {
     mesh::Packet* ack = createAck(ack_hash);
-    if (ack) sendFlood(ack, TXT_ACK_DELAY);
+    if (ack) sendFlood(ack, TXT_ACK_DELAY, path_hash_size);
   } else {
     uint32_t d = TXT_ACK_DELAY;
     if (getExtraAckTransmitCount() > 0) {
@@ -537,14 +537,14 @@ void SensorMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_i
         // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
         mesh::Packet* path = createPathReturn(from->id, secret, packet->path, packet->path_len,
                                               PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
-        if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
+        if (path) sendFlood(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
       } else {
         mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, from->id, secret, reply_data, reply_len);
         if (reply) {
-          if (from->out_path_len >= 0) {  // we have an out_path, so send DIRECT
+          if (from->out_path_len != OUT_PATH_UNKNOWN) {  // we have an out_path, so send DIRECT
             sendDirect(reply, from->out_path, from->out_path_len, SERVER_RESPONSE_DELAY);
           } else {
-            sendFlood(reply, SERVER_RESPONSE_DELAY);
+            sendFlood(reply, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
           }
         }
       }
@@ -569,7 +569,7 @@ void SensorMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_i
                                                   PAYLOAD_TYPE_ACK, (uint8_t *) &ack_hash, 4);
             if (path) sendFlood(path, TXT_ACK_DELAY);
           } else {
-            sendAckTo(*from, ack_hash);
+            sendAckTo(*from, ack_hash, packet->getPathHashSize());
           }
         }
       } else if (flags == TXT_TYPE_CLI_DATA) {  
@@ -596,8 +596,8 @@ void SensorMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_i
 
           auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, from->id, secret, temp, 5 + text_len);
           if (reply) {
-            if (from->out_path_len < 0) {
-              sendFlood(reply, CLI_REPLY_DELAY_MILLIS);
+            if (from->out_path_len == OUT_PATH_UNKNOWN) {
+              sendFlood(reply, CLI_REPLY_DELAY_MILLIS, packet->getPathHashSize());
             } else {
               sendDirect(reply, from->out_path, from->out_path_len, CLI_REPLY_DELAY_MILLIS);
             }
@@ -666,7 +666,7 @@ bool SensorMesh::onPeerPathRecv(mesh::Packet* packet, int sender_idx, const uint
   MESH_DEBUG_PRINTLN("PATH to contact, path_len=%d", (uint32_t) path_len);
   // NOTE: for this impl, we just replace the current 'out_path' regardless, whenever sender sends us a new out_path.
   // FUTURE: could store multiple out_paths per contact, and try to find which is the 'best'(?)
-  memcpy(from->out_path, path, from->out_path_len = path_len);  // store a copy of path, for sendDirect()
+  from->out_path_len = mesh::Packet::copyPath(from->out_path, path, path_len);  // store a copy of path, for sendDirect()
   from->last_activity = getRTCClock()->getCurrentTime();
 
   // REVISIT: maybe make ALL out_paths non-persisted to minimise flash writes??

examples/simple_sensor/SensorMesh.h

@@ -128,7 +128,7 @@ protected:
   void onControlDataRecv(mesh::Packet* packet) override;
   void onAckRecv(mesh::Packet* packet, uint32_t ack_crc) override;
   virtual bool handleIncomingMsg(ClientInfo& from, uint32_t timestamp, uint8_t* data, uint8_t flags, size_t len);
-  void sendAckTo(const ClientInfo& dest, uint32_t ack_hash);
+  void sendAckTo(const ClientInfo& dest, uint32_t ack_hash, uint8_t path_hash_size=1);
 private:
   FILESYSTEM* _fs;
   unsigned long next_local_advert, next_flood_advert;

src/Dispatcher.cpp

@@ -108,6 +108,48 @@ void Dispatcher::loop() {
   checkSend();
 }
 
+bool Dispatcher::tryParsePacket(Packet* pkt, const uint8_t* raw, int len) {
+  int i = 0;
+
+  pkt->header = raw[i++];
+  if (pkt->getPayloadVer() > PAYLOAD_VER_1) {
+    MESH_DEBUG_PRINTLN("%s Dispatcher::checkRecv(): unsupported packet version", getLogDateTime());
+    return false;
+  }
+
+  if (pkt->hasTransportCodes()) {
+    memcpy(&pkt->transport_codes[0], &raw[i], 2); i += 2;
+    memcpy(&pkt->transport_codes[1], &raw[i], 2); i += 2;
+  } else {
+    pkt->transport_codes[0] = pkt->transport_codes[1] = 0;
+  }
+
+  pkt->path_len = raw[i++];
+  uint8_t path_mode = pkt->path_len >> 6;  // upper 2 bits (legacy firmware: 00)
+  if (path_mode == 3) {   // Reserved for future
+    MESH_DEBUG_PRINTLN("%s Dispatcher::checkRecv(): unsupported path mode: 3", getLogDateTime());
+    return false;
+  }
+
+  uint8_t path_byte_len = (pkt->path_len & 63) * pkt->getPathHashSize();
+  if (path_byte_len > MAX_PATH_SIZE || i + path_byte_len > len) {
+    MESH_DEBUG_PRINTLN("%s Dispatcher::checkRecv(): partial or corrupt packet received, len=%d", getLogDateTime(), len);
+    return false;
+  }
+
+  memcpy(pkt->path, &raw[i], path_byte_len); i += path_byte_len;
+
+  pkt->payload_len = len - i;  // payload is remainder
+  if (pkt->payload_len > sizeof(pkt->payload)) {
+    MESH_DEBUG_PRINTLN("%s Dispatcher::checkRecv(): packet payload too big, payload_len=%d", getLogDateTime(), (uint32_t)pkt->payload_len);
+    return false;
+  }
+
+  memcpy(pkt->payload, &raw[i], pkt->payload_len);
+
+  return true;  // success
+}
+
 void Dispatcher::checkRecv() {
   Packet* pkt;
   float score;
@@ -122,45 +164,14 @@ void Dispatcher::checkRecv() {
       if (pkt == NULL) {
         MESH_DEBUG_PRINTLN("%s Dispatcher::checkRecv(): WARNING: received data, no unused packets available!", getLogDateTime());
       } else {
-        int i = 0;
-#ifdef NODE_ID
-        uint8_t sender_id = raw[i++];
-        if (sender_id == NODE_ID - 1 || sender_id == NODE_ID + 1) {  // simulate that NODE_ID can only hear NODE_ID-1 or NODE_ID+1, eg. 3 can't hear 1
-        } else {
-          _mgr->free(pkt);  // put back into pool
-          return;
-        }
-#endif
-
-        pkt->header = raw[i++];
-        if (pkt->hasTransportCodes()) {
-          memcpy(&pkt->transport_codes[0], &raw[i], 2); i += 2;
-          memcpy(&pkt->transport_codes[1], &raw[i], 2); i += 2;
+        if (tryParsePacket(pkt, raw, len)) {
+          pkt->_snr = _radio->getLastSNR() * 4.0f;
+          score = _radio->packetScore(_radio->getLastSNR(), len);
+          air_time = _radio->getEstAirtimeFor(len);
+          rx_air_time += air_time;
         } else {
-          pkt->transport_codes[0] = pkt->transport_codes[1] = 0;
-        }
-        pkt->path_len = raw[i++];
-
-        if (pkt->path_len > MAX_PATH_SIZE || i + pkt->path_len > len) {
-          MESH_DEBUG_PRINTLN("%s Dispatcher::checkRecv(): partial or corrupt packet received, len=%d", getLogDateTime(), len);
           _mgr->free(pkt);  // put back into pool
           pkt = NULL;
-        } else {
-          memcpy(pkt->path, &raw[i], pkt->path_len); i += pkt->path_len;
-
-          pkt->payload_len = len - i;  // payload is remainder
-          if (pkt->payload_len > sizeof(pkt->payload)) {
-            MESH_DEBUG_PRINTLN("%s Dispatcher::checkRecv(): packet payload too big, payload_len=%d", getLogDateTime(), (uint32_t)pkt->payload_len);
-            _mgr->free(pkt);  // put back into pool
-            pkt = NULL;  
-          } else {
-            memcpy(pkt->payload, &raw[i], pkt->payload_len);
-
-            pkt->_snr = _radio->getLastSNR() * 4.0f;
-            score = _radio->packetScore(_radio->getLastSNR(), len);
-            air_time = _radio->getEstAirtimeFor(len);
-            rx_air_time += air_time;
-          }
         }
       }
     } else {
@@ -249,9 +260,6 @@ void Dispatcher::checkSend() {
     int len = 0;
     uint8_t raw[MAX_TRANS_UNIT];
 
-#ifdef NODE_ID
-    raw[len++] = NODE_ID;
-#endif
     raw[len++] = outbound->header;
     if (outbound->hasTransportCodes()) {
       memcpy(&raw[len], &outbound->transport_codes[0], 2); len += 2;

src/Dispatcher.h

@@ -184,6 +184,7 @@ public:
   unsigned long futureMillis(int millis_from_now) const;
 
 private:
+  bool tryParsePacket(Packet* pkt, const uint8_t* raw, int len);
   void checkRecv();
   void checkSend();
 };

src/Identity.h

@@ -20,6 +20,10 @@ public:
     memcpy(dest, pub_key, PATH_HASH_SIZE);    // hash is just prefix of pub_key
     return PATH_HASH_SIZE;
   }
+  int copyHashTo(uint8_t* dest, uint8_t len) const { 
+    memcpy(dest, pub_key, len);    // hash is just prefix of pub_key
+    return len;
+  }
   bool isHashMatch(const uint8_t* hash) const {
     return memcmp(hash, pub_key, PATH_HASH_SIZE) == 0;
   }

src/Mesh.cpp

@@ -39,11 +39,6 @@ int Mesh::searchChannelsByHash(const uint8_t* hash, GroupChannel channels[], int
 }
 
 DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
-  if (pkt->getPayloadVer() > PAYLOAD_VER_1) {  // not supported in this firmware version
-    MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): unsupported packet version", getLogDateTime());
-    return ACTION_RELEASE;
-  }
-
   if (pkt->isRouteDirect() && pkt->getPayloadType() == PAYLOAD_TYPE_TRACE) {
     if (pkt->path_len < MAX_PATH_SIZE) {
       uint8_t i = 0;
@@ -70,14 +65,14 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
   }
 
   if (pkt->isRouteDirect() && pkt->getPayloadType() == PAYLOAD_TYPE_CONTROL && (pkt->payload[0] & 0x80) != 0) {
-    if (pkt->path_len == 0) {
+    if (pkt->getPathHashCount() == 0) {
       onControlDataRecv(pkt);
     }
     // just zero-hop control packets allowed (for this subset of payloads)
     return ACTION_RELEASE;
   }
 
-  if (pkt->isRouteDirect() && pkt->path_len >= PATH_HASH_SIZE) {
+  if (pkt->isRouteDirect() && pkt->getPathHashCount() > 0) {
     // check for 'early received' ACK
     if (pkt->getPayloadType() == PAYLOAD_TYPE_ACK) {
       int i = 0;
@@ -88,7 +83,7 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       }
     }
 
-    if (self_id.isHashMatch(pkt->path) && allowPacketForward(pkt)) {
+    if (self_id.isHashMatch(pkt->path, pkt->getPathHashSize()) && allowPacketForward(pkt)) {
       if (pkt->getPayloadType() == PAYLOAD_TYPE_MULTIPART) {
         return forwardMultipartDirect(pkt);
       } else if (pkt->getPayloadType() == PAYLOAD_TYPE_ACK) {
@@ -158,7 +153,9 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
               if (pkt->getPayloadType() == PAYLOAD_TYPE_PATH) {
                 int k = 0;
                 uint8_t path_len = data[k++];
-                uint8_t* path = &data[k]; k += path_len;
+                uint8_t hash_size = (path_len >> 6) + 1;
+                uint8_t hash_count = path_len & 63;
+                uint8_t* path = &data[k]; k += hash_size*hash_count;
                 uint8_t extra_type = data[k++] & 0x0F;   // upper 4 bits reserved for future use
                 uint8_t* extra = &data[k];
                 uint8_t extra_len = len - k;   // remainder of packet (may be padded with zeroes!)
@@ -293,8 +290,7 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
         if (type == PAYLOAD_TYPE_ACK && pkt->payload_len >= 5) {    // a multipart ACK
           Packet tmp;
           tmp.header = pkt->header;
-          tmp.path_len = pkt->path_len;
-          memcpy(tmp.path, pkt->path, pkt->path_len);
+          tmp.path_len = Packet::copyPath(tmp.path, pkt->path, pkt->path_len);
           tmp.payload_len = pkt->payload_len - 1;
           memcpy(tmp.payload, &pkt->payload[1], tmp.payload_len);
 
@@ -321,27 +317,25 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
 
 void Mesh::removeSelfFromPath(Packet* pkt) {
   // remove our hash from 'path'
-  pkt->path_len -= PATH_HASH_SIZE;
-#if 0
-  memcpy(pkt->path, &pkt->path[PATH_HASH_SIZE], pkt->path_len);
-#elif PATH_HASH_SIZE == 1
-  for (int k = 0; k < pkt->path_len; k++) {  // shuffle bytes by 1
-    pkt->path[k] = pkt->path[k + 1];
+  pkt->setPathHashCount(pkt->getPathHashCount() - 1);  // decrement the count
+
+  uint8_t sz = pkt->getPathHashSize();
+  for (int k = 0; k < pkt->getPathHashCount()*sz; k += sz) {  // shuffle path by 1 'entry'
+    memcpy(&pkt->path[k], &pkt->path[k + sz], sz);
   }
-#else
-  #error "need path remove impl"
-#endif
 }
 
 DispatcherAction Mesh::routeRecvPacket(Packet* packet) {
+  uint8_t n = packet->getPathHashCount();
   if (packet->isRouteFlood() && !packet->isMarkedDoNotRetransmit()
-    && packet->path_len + PATH_HASH_SIZE <= MAX_PATH_SIZE && allowPacketForward(packet)) {
+    && (n + 1)*packet->getPathHashSize() <= MAX_PATH_SIZE && allowPacketForward(packet)) {
     // append this node's hash to 'path'
-    packet->path_len += self_id.copyHashTo(&packet->path[packet->path_len]);
+    self_id.copyHashTo(&packet->path[n * packet->getPathHashSize()], packet->getPathHashSize());
+    packet->setPathHashCount(n + 1);
 
     uint32_t d = getRetransmitDelay(packet);
     // as this propagates outwards, give it lower and lower priority
-    return ACTION_RETRANSMIT_DELAYED(packet->path_len, d);   // give priority to closer sources, than ones further away
+    return ACTION_RETRANSMIT_DELAYED(packet->getPathHashCount(), d);   // give priority to closer sources, than ones further away
   }
   return ACTION_RELEASE;
 }
@@ -353,8 +347,7 @@ DispatcherAction Mesh::forwardMultipartDirect(Packet* pkt) {
   if (type == PAYLOAD_TYPE_ACK && pkt->payload_len >= 5) {    // a multipart ACK
     Packet tmp;
     tmp.header = pkt->header;
-    tmp.path_len = pkt->path_len;
-    memcpy(tmp.path, pkt->path, pkt->path_len);
+    tmp.path_len = Packet::copyPath(tmp.path, pkt->path, pkt->path_len);
     tmp.payload_len = pkt->payload_len - 1;
     memcpy(tmp.payload, &pkt->payload[1], tmp.payload_len);
 
@@ -376,7 +369,7 @@ void Mesh::routeDirectRecvAcks(Packet* packet, uint32_t delay_millis) {
       delay_millis += getDirectRetransmitDelay(packet) + 300;
       auto a1 = createMultiAck(crc, extra);
       if (a1) {
-        memcpy(a1->path, packet->path, a1->path_len = packet->path_len);
+        a1->path_len = Packet::copyPath(a1->path, packet->path, packet->path_len);
         a1->header &= ~PH_ROUTE_MASK;
         a1->header |= ROUTE_TYPE_DIRECT;
         sendPacket(a1, 0, delay_millis);
@@ -386,7 +379,7 @@ void Mesh::routeDirectRecvAcks(Packet* packet, uint32_t delay_millis) {
 
     auto a2 = createAck(crc);
     if (a2) {
-      memcpy(a2->path, packet->path, a2->path_len = packet->path_len);
+      a2->path_len = Packet::copyPath(a2->path, packet->path, packet->path_len);
       a2->header &= ~PH_ROUTE_MASK;
       a2->header |= ROUTE_TYPE_DIRECT;
       sendPacket(a2, 0, delay_millis);
@@ -439,7 +432,10 @@ Packet* Mesh::createPathReturn(const Identity& dest, const uint8_t* secret, cons
 }
 
 Packet* Mesh::createPathReturn(const uint8_t* dest_hash, const uint8_t* secret, const uint8_t* path, uint8_t path_len, uint8_t extra_type, const uint8_t*extra, size_t extra_len) {
-  if (path_len + extra_len + 5 > MAX_COMBINED_PATH) return NULL;  // too long!!
+  uint8_t path_hash_size = (path_len >> 6) + 1;
+  uint8_t path_hash_count = path_len & 63;
+
+  if (path_hash_count*path_hash_size + extra_len + 5 > MAX_COMBINED_PATH) return NULL;  // too long!!
 
   Packet* packet = obtainNewPacket();
   if (packet == NULL) {
@@ -457,7 +453,7 @@ Packet* Mesh::createPathReturn(const uint8_t* dest_hash, const uint8_t* secret,
     uint8_t data[MAX_PACKET_PAYLOAD];
 
     data[data_len++] = path_len;
-    memcpy(&data[data_len], path, path_len); data_len += path_len;
+    memcpy(&data[data_len], path, path_hash_count*path_hash_size); data_len += path_hash_count*path_hash_size;
     if (extra_len > 0) {
       data[data_len++] = extra_type;
       memcpy(&data[data_len], extra, extra_len); data_len += extra_len;
@@ -624,15 +620,19 @@ Packet* Mesh::createControlData(const uint8_t* data, size_t len) {
   return packet;
 }
 
-void Mesh::sendFlood(Packet* packet, uint32_t delay_millis) {
+void Mesh::sendFlood(Packet* packet, uint32_t delay_millis, uint8_t path_hash_size) {
   if (packet->getPayloadType() == PAYLOAD_TYPE_TRACE) {
     MESH_DEBUG_PRINTLN("%s Mesh::sendFlood(): TRACE type not suspported", getLogDateTime());
     return;
   }
+  if (path_hash_size == 0 || path_hash_size > 3) {
+    MESH_DEBUG_PRINTLN("%s Mesh::sendFlood(): invalid path_hash_size", getLogDateTime());
+    return;
+  }
 
   packet->header &= ~PH_ROUTE_MASK;
   packet->header |= ROUTE_TYPE_FLOOD;
-  packet->path_len = 0;
+  packet->setPathHashSizeAndCount(path_hash_size, 0);
 
   _tables->hasSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
 
@@ -647,17 +647,21 @@ void Mesh::sendFlood(Packet* packet, uint32_t delay_millis) {
   sendPacket(packet, pri, delay_millis);
 }
 
-void Mesh::sendFlood(Packet* packet, uint16_t* transport_codes, uint32_t delay_millis) {
+void Mesh::sendFlood(Packet* packet, uint16_t* transport_codes, uint32_t delay_millis, uint8_t path_hash_size) {
   if (packet->getPayloadType() == PAYLOAD_TYPE_TRACE) {
     MESH_DEBUG_PRINTLN("%s Mesh::sendFlood(): TRACE type not suspported", getLogDateTime());
     return;
   }
+  if (path_hash_size == 0 || path_hash_size > 3) {
+    MESH_DEBUG_PRINTLN("%s Mesh::sendFlood(): invalid path_hash_size", getLogDateTime());
+    return;
+  }
 
   packet->header &= ~PH_ROUTE_MASK;
   packet->header |= ROUTE_TYPE_TRANSPORT_FLOOD;
   packet->transport_codes[0] = transport_codes[0];
   packet->transport_codes[1] = transport_codes[1];
-  packet->path_len = 0;
+  packet->setPathHashSizeAndCount(path_hash_size, 0);
 
   _tables->hasSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
 
@@ -679,13 +683,13 @@ void Mesh::sendDirect(Packet* packet, const uint8_t* path, uint8_t path_len, uin
   uint8_t pri;
   if (packet->getPayloadType() == PAYLOAD_TYPE_TRACE) {   // TRACE packets are different
     // for TRACE packets, path is appended to end of PAYLOAD. (path is used for SNR's)
-    memcpy(&packet->payload[packet->payload_len], path, path_len);
+    memcpy(&packet->payload[packet->payload_len], path, path_len);  // NOTE: path_len here can be > 64, and NOT in the new scheme
     packet->payload_len += path_len;
 
     packet->path_len = 0;
     pri = 5;   // maybe make this configurable
   } else {
-    memcpy(packet->path, path, packet->path_len = path_len);
+    packet->path_len = Packet::copyPath(packet->path, path, path_len);
     if (packet->getPayloadType() == PAYLOAD_TYPE_PATH) {
       pri = 1;   // slightly less priority
     } else {

src/Mesh.h

@@ -196,13 +196,13 @@ public:
   /**
    * \brief  send a locally-generated Packet with flood routing
   */
-  void sendFlood(Packet* packet, uint32_t delay_millis=0);
+  void sendFlood(Packet* packet, uint32_t delay_millis=0, uint8_t path_hash_size=1);
 
   /**
    * \brief  send a locally-generated Packet with flood routing
    * \param transport_codes   array of 2 codes to attach to packet
   */
-  void sendFlood(Packet* packet, uint16_t* transport_codes, uint32_t delay_millis=0);
+  void sendFlood(Packet* packet, uint16_t* transport_codes, uint32_t delay_millis=0, uint8_t path_hash_size=1);
 
   /**
    * \brief  send a locally-generated Packet with Direct routing

src/Packet.cpp

@@ -10,8 +10,19 @@ Packet::Packet() {
   payload_len = 0;
 }
 
+uint8_t Packet::copyPath(uint8_t* dest, const uint8_t* src, uint8_t path_len) {
+  uint8_t hash_count = path_len & 63;
+  uint8_t hash_size = (path_len >> 6) + 1;
+  if (hash_count*hash_size > MAX_PATH_SIZE) {
+    MESH_DEBUG_PRINTLN("Packet::copyPath, invalid path_len=%d", (uint32_t)path_len);
+    return 0;   // Error
+  }
+  memcpy(dest, src, hash_count*hash_size);
+  return path_len;
+}
+
 int Packet::getRawLength() const {
-  return 2 + path_len + payload_len + (hasTransportCodes() ? 4 : 0);
+  return 2 + getPathByteLen() + payload_len + (hasTransportCodes() ? 4 : 0);
 }
 
 void Packet::calculatePacketHash(uint8_t* hash) const {

src/Packet.h

@@ -76,6 +76,14 @@ public:
    */
   uint8_t getPayloadVer() const { return (header >> PH_VER_SHIFT) & PH_VER_MASK; }
 
+  uint8_t getPathHashSize() const { return (path_len >> 6) + 1; }
+  uint8_t getPathHashCount() const { return path_len & 63; }
+  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); }
+
+  static uint8_t copyPath(uint8_t* dest, const uint8_t* src, uint8_t path_len);
+
   void markDoNotRetransmit() { header = 0xFF; }
   bool isMarkedDoNotRetransmit() const { return header == 0xFF; }
 

src/helpers/BaseChatMesh.cpp

@@ -39,7 +39,7 @@ mesh::Packet* BaseChatMesh::createSelfAdvert(const char* name, double lat, doubl
 }
 
 void BaseChatMesh::sendAckTo(const ContactInfo& dest, uint32_t ack_hash) {
-  if (dest.out_path_len < 0) {
+  if (dest.out_path_len == OUT_PATH_UNKNOWN) {
     mesh::Packet* ack = createAck(ack_hash);
     if (ack) sendFloodScoped(dest, ack, TXT_ACK_DELAY);
   } else {
@@ -92,7 +92,7 @@ ContactInfo* BaseChatMesh::allocateContactSlot() {
 void BaseChatMesh::populateContactFromAdvert(ContactInfo& ci, const mesh::Identity& id, const AdvertDataParser& parser, uint32_t timestamp) {
   memset(&ci, 0, sizeof(ci));
   ci.id = id;
-  ci.out_path_len = -1;  // initially out_path is unknown
+  ci.out_path_len = OUT_PATH_UNKNOWN;
   StrHelper::strncpy(ci.name, parser.getName(), sizeof(ci.name));
   ci.type = parser.getType();
   if (parser.hasLatLon()) {
@@ -263,7 +263,7 @@ void BaseChatMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender
       } else {
         mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, from.id, secret, temp_buf, reply_len);
         if (reply) {
-          if (from.out_path_len >= 0) {  // we have an out_path, so send DIRECT
+          if (from.out_path_len != OUT_PATH_UNKNOWN) {  // we have an out_path, so send DIRECT
             sendDirect(reply, from.out_path, from.out_path_len, SERVER_RESPONSE_DELAY);
           } else {
             sendFloodScoped(from, reply, SERVER_RESPONSE_DELAY);
@@ -273,7 +273,7 @@ void BaseChatMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender
     }
   } else if (type == PAYLOAD_TYPE_RESPONSE && len > 0) {
     onContactResponse(from, data, len);
-    if (packet->isRouteFlood() && from.out_path_len >= 0) {
+    if (packet->isRouteFlood() && from.out_path_len != OUT_PATH_UNKNOWN) {
       // we have direct path, but other node is still sending flood response, so maybe they didn't receive reciprocal path properly(?)
       handleReturnPathRetry(from, packet->path, packet->path_len);
     }
@@ -295,7 +295,7 @@ bool BaseChatMesh::onPeerPathRecv(mesh::Packet* packet, int sender_idx, const ui
 bool BaseChatMesh::onContactPathRecv(ContactInfo& from, uint8_t* in_path, uint8_t in_path_len, uint8_t* out_path, uint8_t out_path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) {
   // NOTE: default impl, we just replace the current 'out_path' regardless, whenever sender sends us a new out_path.
   // FUTURE: could store multiple out_paths per contact, and try to find which is the 'best'(?)
-  memcpy(from.out_path, out_path, from.out_path_len = out_path_len);  // store a copy of path, for sendDirect()
+  from.out_path_len = mesh::Packet::copyPath(from.out_path, out_path, out_path_len);  // store a copy of path, for sendDirect()
   from.lastmod = getRTCClock()->getCurrentTime();
 
   onContactPathUpdated(from);
@@ -317,7 +317,7 @@ void BaseChatMesh::onAckRecv(mesh::Packet* packet, uint32_t ack_crc) {
     txt_send_timeout = 0;   // matched one we're waiting for, cancel timeout timer
     packet->markDoNotRetransmit();   // ACK was for this node, so don't retransmit
 
-    if (packet->isRouteFlood() && from->out_path_len >= 0) {
+    if (packet->isRouteFlood() && from->out_path_len != OUT_PATH_UNKNOWN) {
       // we have direct path, but other node is still sending flood, so maybe they didn't receive reciprocal path properly(?)
       handleReturnPathRetry(*from, packet->path, packet->path_len);
     }
@@ -386,7 +386,7 @@ int  BaseChatMesh::sendMessage(const ContactInfo& recipient, uint32_t timestamp,
   uint32_t t = _radio->getEstAirtimeFor(pkt->getRawLength());
 
   int rc;
-  if (recipient.out_path_len < 0) {
+  if (recipient.out_path_len == OUT_PATH_UNKNOWN) {
     sendFloodScoped(recipient, pkt);
     txt_send_timeout = futureMillis(est_timeout = calcFloodTimeoutMillisFor(t));
     rc = MSG_SEND_SENT_FLOOD;
@@ -412,7 +412,7 @@ int  BaseChatMesh::sendCommandData(const ContactInfo& recipient, uint32_t timest
 
   uint32_t t = _radio->getEstAirtimeFor(pkt->getRawLength());
   int rc;
-  if (recipient.out_path_len < 0) {
+  if (recipient.out_path_len == OUT_PATH_UNKNOWN) {
     sendFloodScoped(recipient, pkt);
     txt_send_timeout = futureMillis(est_timeout = calcFloodTimeoutMillisFor(t));
     rc = MSG_SEND_SENT_FLOOD;
@@ -500,7 +500,7 @@ int BaseChatMesh::sendLogin(const ContactInfo& recipient, const char* password,
   }
   if (pkt) {
     uint32_t t = _radio->getEstAirtimeFor(pkt->getRawLength());
-    if (recipient.out_path_len < 0) {
+    if (recipient.out_path_len == OUT_PATH_UNKNOWN) {
       sendFloodScoped(recipient, pkt);
       est_timeout = calcFloodTimeoutMillisFor(t);
       return MSG_SEND_SENT_FLOOD;
@@ -525,7 +525,7 @@ int BaseChatMesh::sendAnonReq(const ContactInfo& recipient, const uint8_t* data,
   }
   if (pkt) {
     uint32_t t = _radio->getEstAirtimeFor(pkt->getRawLength());
-    if (recipient.out_path_len < 0) {
+    if (recipient.out_path_len == OUT_PATH_UNKNOWN) {
       sendFloodScoped(recipient, pkt);
       est_timeout = calcFloodTimeoutMillisFor(t);
       return MSG_SEND_SENT_FLOOD;
@@ -552,7 +552,7 @@ int  BaseChatMesh::sendRequest(const ContactInfo& recipient, const uint8_t* req_
   }
   if (pkt) {
     uint32_t t = _radio->getEstAirtimeFor(pkt->getRawLength());
-    if (recipient.out_path_len < 0) {
+    if (recipient.out_path_len == OUT_PATH_UNKNOWN) {
       sendFloodScoped(recipient, pkt);
       est_timeout = calcFloodTimeoutMillisFor(t);
       return MSG_SEND_SENT_FLOOD;
@@ -579,7 +579,7 @@ int  BaseChatMesh::sendRequest(const ContactInfo& recipient, uint8_t req_type, u
   }
   if (pkt) {
     uint32_t t = _radio->getEstAirtimeFor(pkt->getRawLength());
-    if (recipient.out_path_len < 0) {
+    if (recipient.out_path_len == OUT_PATH_UNKNOWN) {
       sendFloodScoped(recipient, pkt);
       est_timeout = calcFloodTimeoutMillisFor(t);
       return MSG_SEND_SENT_FLOOD;
@@ -683,7 +683,7 @@ void BaseChatMesh::checkConnections() {
         MESH_DEBUG_PRINTLN("checkConnections(): Keep_alive contact not found!");
         continue;
       }
-      if (contact->out_path_len < 0) {
+      if (contact->out_path_len == OUT_PATH_UNKNOWN) {
         MESH_DEBUG_PRINTLN("checkConnections(): Keep_alive contact, no out_path!");
         continue;
       }
@@ -710,7 +710,7 @@ void BaseChatMesh::checkConnections() {
 }
 
 void BaseChatMesh::resetPathTo(ContactInfo& recipient) {
-  recipient.out_path_len = -1;
+  recipient.out_path_len = OUT_PATH_UNKNOWN;
 }
 
 static ContactInfo* table;  // pass via global :-(

src/helpers/ClientACL.cpp

@@ -114,7 +114,7 @@ ClientInfo* ClientACL::putClient(const mesh::Identity& id, uint8_t init_perms) {
   memset(c, 0, sizeof(*c));
   c->permissions = init_perms;
   c->id = id;
-  c->out_path_len = -1;  // initially out_path is unknown
+  c->out_path_len = OUT_PATH_UNKNOWN;
   return c;
 }
 

src/helpers/ClientACL.h

@@ -10,10 +10,12 @@
 #define PERM_ACL_READ_WRITE    2
 #define PERM_ACL_ADMIN         3
 
+#define OUT_PATH_UNKNOWN  0xFF
+
 struct ClientInfo {
   mesh::Identity id;
   uint8_t permissions;
-  int8_t out_path_len;
+  uint8_t out_path_len;
   uint8_t out_path[MAX_PATH_SIZE];
   uint8_t shared_secret[PUB_KEY_SIZE];
   uint32_t last_timestamp;   // by THEIR clock  (transient)

src/helpers/ContactInfo.h

@@ -3,12 +3,14 @@
 #include <Arduino.h>
 #include <Mesh.h>
 
+#define OUT_PATH_UNKNOWN   0xFF
+
 struct ContactInfo {
   mesh::Identity id;
   char name[32];
   uint8_t type;   // on of ADV_TYPE_*
   uint8_t flags;
-  int8_t out_path_len;
+  uint8_t out_path_len;
   mutable bool shared_secret_valid; // flag to indicate if shared_secret has been calculated
   uint8_t out_path[MAX_PATH_SIZE];
   uint32_t last_advert_timestamp;   // by THEIR clock