Add source-based routing support (#862)

* Add source-based routing support

* include neighbors in ANNOUNCE

---------

Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: callebtc <93376500+callebtc@users.noreply.github.com>

bitchat/Protocols/BinaryProtocol.swift

@@ -137,6 +137,7 @@ struct BinaryProtocol {
         static let hasRecipient: UInt8 = 0x01
         static let hasSignature: UInt8 = 0x02
         static let isCompressed: UInt8 = 0x04
+        static let hasRoute: UInt8 = 0x08
     }
     
     // Encode BitchatPacket to binary format
@@ -160,8 +161,21 @@ struct BinaryProtocol {
         }
 
         let lengthFieldBytes = lengthFieldSize(for: version)
+        let originalRoute = packet.route ?? []
+        if originalRoute.contains(where: { $0.isEmpty }) { return nil }
+        let sanitizedRoute: [Data] = originalRoute.map { hop in
+            if hop.count == senderIDSize { return hop }
+            if hop.count > senderIDSize { return Data(hop.prefix(senderIDSize)) }
+            var padded = hop
+            padded.append(Data(repeating: 0, count: senderIDSize - hop.count))
+            return padded
+        }
+        guard sanitizedRoute.count <= 255 else { return nil }
+
+        let hasRoute = !sanitizedRoute.isEmpty
+        let routeLength = hasRoute ? 1 + sanitizedRoute.count * senderIDSize : 0
         let originalSizeFieldBytes = isCompressed ? lengthFieldBytes : 0
-        let payloadDataSize = payload.count + originalSizeFieldBytes
+        let payloadDataSize = routeLength + payload.count + originalSizeFieldBytes
 
         if version == 1 && payloadDataSize > Int(UInt16.max) { return nil }
         if version == 2 && payloadDataSize > Int(UInt32.max) { return nil }
@@ -185,6 +199,7 @@ struct BinaryProtocol {
         if packet.recipientID != nil { flags |= Flags.hasRecipient }
         if packet.signature != nil { flags |= Flags.hasSignature }
         if isCompressed { flags |= Flags.isCompressed }
+        if hasRoute { flags |= Flags.hasRoute }
         data.append(flags)
 
         if version == 2 {
@@ -212,6 +227,13 @@ struct BinaryProtocol {
             }
         }
 
+        if hasRoute {
+            data.append(UInt8(sanitizedRoute.count))
+            for hop in sanitizedRoute {
+                data.append(hop)
+            }
+        }
+
         if isCompressed, let originalSize = originalPayloadSize {
             if version == 2 {
                 let value = UInt32(originalSize)
@@ -321,9 +343,27 @@ struct BinaryProtocol {
                 if recipientID == nil { return nil }
             }
 
+            var route: [Data]? = nil
+            var remainingPayloadBytes = payloadLength
+
+            if (flags & Flags.hasRoute) != 0 {
+                guard remainingPayloadBytes >= 1, let routeCount = read8() else { return nil }
+                remainingPayloadBytes -= 1
+                if routeCount > 0 {
+                    var hops: [Data] = []
+                    for _ in 0..<Int(routeCount) {
+                        guard remainingPayloadBytes >= senderIDSize,
+                              let hop = readData(senderIDSize) else { return nil }
+                        remainingPayloadBytes -= senderIDSize
+                        hops.append(hop)
+                    }
+                    route = hops
+                }
+            }
+
             let payload: Data
             if isCompressed {
-                guard payloadLength >= lengthFieldBytes else { return nil }
+                guard remainingPayloadBytes >= lengthFieldBytes else { return nil }
                 let originalSize: Int
                 if version == 2 {
                     guard let rawSize = read32() else { return nil }
@@ -332,16 +372,12 @@ struct BinaryProtocol {
                     guard let rawSize = read16() else { return nil }
                     originalSize = Int(rawSize)
                 }
-                // Guard to keep decompression bounded to sane BLE payload limits
-                // Use maxFramedFileBytes to account for TLV overhead in file transfer payloads
+                remainingPayloadBytes -= lengthFieldBytes
                 guard originalSize >= 0 && originalSize <= FileTransferLimits.maxFramedFileBytes else { return nil }
-                let compressedSize = payloadLength - lengthFieldBytes
-                guard compressedSize >= 0, let compressed = readData(compressedSize) else { return nil }
+                let compressedSize = remainingPayloadBytes
+                guard compressedSize > 0, let compressed = readData(compressedSize) else { return nil }
+                remainingPayloadBytes = 0
 
-                // Validate compression ratio to prevent zip bomb attacks
-                // Primary protection: originalSize capped at 1MB (line 336)
-                // Defense-in-depth: reject extreme ratios (prevents DoS via memory allocation)
-                guard compressedSize > 0 else { return nil }
                 let compressionRatio = Double(originalSize) / Double(compressedSize)
                 guard compressionRatio <= 50_000.0 else {
                     SecureLogger.warning("🚫 Suspicious compression ratio: \(String(format: "%.0f", compressionRatio)):1", category: .security)
@@ -352,7 +388,9 @@ struct BinaryProtocol {
                       decompressed.count == originalSize else { return nil }
                 payload = decompressed
             } else {
-                guard let rawPayload = readData(payloadLength) else { return nil }
+                guard remainingPayloadBytes >= 0,
+                      let rawPayload = readData(remainingPayloadBytes) else { return nil }
+                remainingPayloadBytes = 0
                 payload = rawPayload
             }
 
@@ -372,7 +410,8 @@ struct BinaryProtocol {
                 payload: payload,
                 signature: signature,
                 ttl: ttl,
-                version: version
+                version: version,
+                route: route
             )
         }
     }

bitchat/Protocols/Packets.swift

@@ -6,11 +6,13 @@ struct AnnouncementPacket {
     let nickname: String
     let noisePublicKey: Data            // Noise static public key (Curve25519.KeyAgreement)
     let signingPublicKey: Data          // Ed25519 public key for signing
+    let directNeighbors: [Data]?        // 8-byte peer IDs
 
     private enum TLVType: UInt8 {
         case nickname = 0x01
         case noisePublicKey = 0x02
         case signingPublicKey = 0x03
+        case directNeighbors = 0x04
     }
 
     func encode() -> Data? {
@@ -35,6 +37,16 @@ struct AnnouncementPacket {
         data.append(TLVType.signingPublicKey.rawValue)
         data.append(UInt8(signingPublicKey.count))
         data.append(signingPublicKey)
+        
+        // TLV for direct neighbors (optional)
+        if let neighbors = directNeighbors, !neighbors.isEmpty {
+            let neighborsData = neighbors.prefix(10).reduce(Data()) { $0 + $1 }
+            if !neighborsData.isEmpty && neighborsData.count % 8 == 0 {
+                data.append(TLVType.directNeighbors.rawValue)
+                data.append(UInt8(neighborsData.count))
+                data.append(neighborsData)
+            }
+        }
 
         return data
     }
@@ -44,6 +56,7 @@ struct AnnouncementPacket {
         var nickname: String?
         var noisePublicKey: Data?
         var signingPublicKey: Data?
+        var directNeighbors: [Data]?
 
         while offset + 2 <= data.count {
             let typeRaw = data[offset]
@@ -63,6 +76,17 @@ struct AnnouncementPacket {
                     noisePublicKey = Data(value)
                 case .signingPublicKey:
                     signingPublicKey = Data(value)
+                case .directNeighbors:
+                    if length > 0 && length % 8 == 0 {
+                        var neighbors = [Data]()
+                        let count = length / 8
+                        for i in 0..<count {
+                            let start = value.startIndex + i * 8
+                            let end = start + 8
+                            neighbors.append(Data(value[start..<end]))
+                        }
+                        directNeighbors = neighbors
+                    }
                 }
             } else {
                 // Unknown TLV; skip (tolerant decoder for forward compatibility)
@@ -74,7 +98,8 @@ struct AnnouncementPacket {
         return AnnouncementPacket(
             nickname: nickname,
             noisePublicKey: noisePublicKey,
-            signingPublicKey: signingPublicKey
+            signingPublicKey: signingPublicKey,
+            directNeighbors: directNeighbors
         )
     }
 }