Fix isFromUs and account for channel hashes instead of indexes

src/mesh/Channels.cpp

@@ -459,4 +459,15 @@ bool Channels::setDefaultPresetCryptoForHash(ChannelHash channelHash)
 int16_t Channels::setActiveByIndex(ChannelIndex channelIndex)
 {
     return setCrypto(channelIndex);
+}
+
+int8_t Channels::getIndexByHash(ChannelHash channelHash)
+{
+    // Iterate through all channels to find the one with matching hash
+    for (ChannelIndex i = 0; i < getNumChannels(); i++) {
+        if (getHash(i) == channelHash) {
+            return i;
+        }
+    }
+    return -1; // Hash not found
 }

src/mesh/Channels.h

@@ -96,6 +96,9 @@ class Channels
 
     bool setDefaultPresetCryptoForHash(ChannelHash channelHash);
 
+    /** Return the channel index for the specified channel hash, or -1 for not found */
+    int8_t getIndexByHash(ChannelHash channelHash);
+
   private:
     /** Given a channel index, change to use the crypto key specified by that index
      *
@@ -103,9 +106,6 @@ class Channels
      */
     int16_t setCrypto(ChannelIndex chIndex);
 
-    /** Return the channel index for the specified channel hash, or -1 for not found */
-    int8_t getIndexByHash(ChannelHash channelHash);
-
     /** Given a channel number, return the (0 to 255) hash for that channel
      * If no suitable channel could be found, return -1
      *

src/mesh/Router.cpp

@@ -357,10 +357,16 @@ ErrorCode Router::send(meshtastic_MeshPacket *p)
         }
 #endif
 #if HAS_UDP_MULTICAST
-        // Only publish to UDP if we're the original transmitter of the packet
-        if (udpHandler && config.network.enabled_protocols & meshtastic_Config_NetworkConfig_ProtocolFlags_UDP_BROADCAST &&
-            isFromUs(p)) {
-            udpHandler->onSend(const_cast<meshtastic_MeshPacket *>(p), chIndex);
+        if (udpHandler && config.network.enabled_protocols & meshtastic_Config_NetworkConfig_ProtocolFlags_UDP_BROADCAST) {
+            // We must have at least one channel setup for with uplink_enabled
+            bool uplinkEnabled = false;
+            for (int i = 0; i <= 7; i++) {
+                if (channels.getByIndex(i).settings.uplink_enabled)
+                    uplinkEnabled = true;
+            }
+            if (uplinkEnabled) {
+                udpHandler->onSend(const_cast<meshtastic_MeshPacket *>(p), chIndex);
+            }
         }
 #endif
         packetPool.release(p_decoded);
@@ -369,7 +375,35 @@ ErrorCode Router::send(meshtastic_MeshPacket *p)
     // For packets that are already encrypted, we need to determine the channel from packet info
     else if (udpHandler && config.network.enabled_protocols & meshtastic_Config_NetworkConfig_ProtocolFlags_UDP_BROADCAST &&
              isFromUs(p)) {
-        udpHandler->onSend(const_cast<meshtastic_MeshPacket *>(p), p->channel);
+        // Check if any channel has uplink enabled (for PKI support)
+        bool uplinkEnabled = false;
+        for (int i = 0; i <= 7; i++) {
+            if (channels.getByIndex(i).settings.uplink_enabled) {
+                uplinkEnabled = true;
+                break;
+            }
+        }
+        if (uplinkEnabled) {
+            ChannelIndex chIndex = 0; // Default to primary channel
+
+            // For PKI encrypted packets, use default channel if at least one channel has uplink
+            if (p->pki_encrypted) {
+                for (int i = 0; i <= 7; i++) {
+                    if (channels.getByIndex(i).settings.uplink_enabled) {
+                        chIndex = i;
+                        break;
+                    }
+                }
+                udpHandler->onSend(const_cast<meshtastic_MeshPacket *>(p), chIndex);
+            } else {
+                // For regular channel PSK encrypted packets, try to find the channel by hash
+                int8_t foundIndex = channels.getIndexByHash(p->channel);
+                if (foundIndex >= 0) {
+                    chIndex = foundIndex;
+                    udpHandler->onSend(const_cast<meshtastic_MeshPacket *>(p), chIndex);
+                }
+            }
+        }
     }
 #endif
 

src/mesh/udp/UdpMulticastHandler.h

@@ -54,10 +54,17 @@ class UdpMulticastHandler final
         LOG_DEBUG("Decoding MeshPacket from UDP len=%u", packetLength);
         bool isPacketDecoded = pb_decode_from_bytes(packet.data(), packetLength, &meshtastic_MeshPacket_msg, &mp);
         if (isPacketDecoded && router && mp.which_payload_variant == meshtastic_MeshPacket_encrypted_tag) {
+            // Convert channel hash to index for downlink check
+            int8_t chIndex = channels.getIndexByHash(mp.channel);
+            if (chIndex < 0) {
+                LOG_DEBUG("UDP received packet with unknown channel hash 0x%x", mp.channel);
+                return;
+            }
+
             // Check if downlink is enabled for this channel
-            auto &ch = channels.getByIndex(mp.channel);
+            auto &ch = channels.getByIndex(chIndex);
             if (!ch.settings.downlink_enabled) {
-                LOG_DEBUG("UDP downlink disabled for channel %d", mp.channel);
+                LOG_DEBUG("UDP downlink disabled for channel %d", chIndex);
                 return;
             }