v25.15.0

changelog.md

@@ -1,5 +1,27 @@
 # Changelog
 
+## 2026-03-19 - 25.15.0 - feat(readme)
+document UDP, QUIC, and HTTP/3 support in the README
+
+- Adds README examples for UDP datagram handlers, QUIC/HTTP3 forwarding, and dual-stack TCP/UDP routes
+- Expands configuration and API reference sections to cover transport matching, UDP/QUIC options, backend transport selection, and UDP metrics
+- Updates architecture and feature descriptions to reflect UDP, QUIC, HTTP/3, and datagram handler capabilities
+
+## 2026-03-19 - 25.14.1 - fix(deps)
+update build and runtime dependencies and align route validation test expectations
+
+- split the test preparation step into a dedicated test:before script while keeping test execution separate
+- bump development tooling and runtime package versions in package.json
+- adjust the route validation test to match the current generic handler error message
+
+## 2026-03-19 - 25.14.0 - feat(udp,http3)
+add UDP datagram handler relay support and stream HTTP/3 request bodies to backends
+
+- establish a persistent Unix socket relay for UDP datagram handlers and process handler replies back to clients
+- update route validation and smart proxy route reload logic to support datagramHandler routes
+- record UDP, QUIC, and HTTP/3 byte metrics more accurately, including request bytes in and UDP session cleanup connection tracking
+- add integration tests for UDP forwarding, datagram handlers, and UDP metrics
+
 ## 2026-03-19 - 25.13.0 - feat(smart-proxy)
 add UDP transport support with QUIC/HTTP3 routing and datagram handler relay
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@push.rocks/smartproxy",
-  "version": "25.13.0",
+  "version": "25.15.0",
   "private": false,
   "description": "A powerful proxy package with unified route-based configuration for high traffic management. Features include SSL/TLS support, flexible routing patterns, WebSocket handling, advanced security options, and automatic ACME certificate management.",
   "main": "dist_ts/index.js",
@@ -9,27 +9,28 @@
   "author": "Lossless GmbH",
   "license": "MIT",
   "scripts": {
-    "test": "(tsrust) && (tstest test/**/test*.ts --verbose --timeout 60 --logfile)",
+    "test:before": "(tsrust)",
+    "test": "(tstest test/**/test*.ts --verbose --timeout 60 --logfile)",
     "build": "(tsbuild tsfolders --allowimplicitany) && (tsrust)",
     "format": "(gitzone format)",
     "buildDocs": "tsdoc"
   },
   "devDependencies": {
-    "@git.zone/tsbuild": "^4.1.2",
+    "@git.zone/tsbuild": "^4.3.0",
     "@git.zone/tsrun": "^2.0.1",
     "@git.zone/tsrust": "^1.3.0",
-    "@git.zone/tstest": "^3.1.8",
+    "@git.zone/tstest": "^3.5.0",
     "@push.rocks/smartserve": "^2.0.1",
-    "@types/node": "^25.2.3",
+    "@types/node": "^25.5.0",
     "typescript": "^5.9.3",
     "why-is-node-running": "^3.2.2"
   },
   "dependencies": {
     "@push.rocks/smartcrypto": "^2.0.4",
-    "@push.rocks/smartlog": "^3.1.10",
-    "@push.rocks/smartrust": "^1.2.1",
-    "@tsclass/tsclass": "^9.3.0",
-    "minimatch": "^10.2.0"
+    "@push.rocks/smartlog": "^3.2.1",
+    "@push.rocks/smartrust": "^1.3.2",
+    "@tsclass/tsclass": "^9.5.0",
+    "minimatch": "^10.2.4"
   },
   "files": [
     "ts/**/*",

readme.md

@@ -1,6 +1,6 @@
 # @push.rocks/smartproxy 🚀
 
-**A high-performance, Rust-powered proxy toolkit for Node.js** — unified route-based configuration for SSL/TLS termination, HTTP/HTTPS reverse proxying, WebSocket support, load balancing, custom protocol handlers, and kernel-level NFTables forwarding.
+**A high-performance, Rust-powered proxy toolkit for Node.js** — unified route-based configuration for SSL/TLS termination, HTTP/HTTPS reverse proxying, WebSocket support, UDP/QUIC/HTTP3, load balancing, custom protocol handlers, and kernel-level NFTables forwarding.
 
 ## 📦 Installation
 
@@ -16,9 +16,9 @@ For reporting bugs, issues, or security vulnerabilities, please visit [community
 
 ## 🎯 What is SmartProxy?
 
-SmartProxy is a production-ready proxy solution that takes the complexity out of traffic management. Under the hood, all networking — TCP, TLS, HTTP reverse proxy, connection tracking, security enforcement, and NFTables — is handled by a **Rust engine** for maximum performance, while you configure everything through a clean TypeScript API with full type safety.
+SmartProxy is a production-ready proxy solution that takes the complexity out of traffic management. Under the hood, all networking — TCP, UDP, TLS, HTTP reverse proxy, QUIC/HTTP3, connection tracking, security enforcement, and NFTables — is handled by a **Rust engine** for maximum performance, while you configure everything through a clean TypeScript API with full type safety.
 
-Whether you're building microservices, deploying edge infrastructure, or need a battle-tested reverse proxy with automatic Let's Encrypt certificates, SmartProxy has you covered.
+Whether you're building microservices, deploying edge infrastructure, proxying UDP-based protocols, or need a battle-tested reverse proxy with automatic Let's Encrypt certificates, SmartProxy has you covered.
 
 ### ⚡ Key Features
 
@@ -29,11 +29,12 @@ Whether you're building microservices, deploying edge infrastructure, or need a
 | 🔒 **Automatic SSL/TLS** | Zero-config HTTPS with Let's Encrypt ACME integration |
 | 🎯 **Flexible Matching** | Route by port, domain, path, protocol, client IP, TLS version, headers, or custom logic |
 | 🚄 **High-Performance** | Choose between user-space or kernel-level (NFTables) forwarding |
+| 📡 **UDP & QUIC/HTTP3** | First-class UDP transport, datagram handlers, QUIC tunneling, and HTTP/3 support |
 | ⚖️ **Load Balancing** | Round-robin, least-connections, IP-hash with health checks |
 | 🛡️ **Enterprise Security** | IP filtering, rate limiting, basic auth, JWT auth, connection limits |
 | 🔌 **WebSocket Support** | First-class WebSocket proxying with ping/pong keep-alive |
-| 🎮 **Custom Protocols** | Socket handlers for implementing any protocol in TypeScript |
-| 📊 **Live Metrics** | Real-time throughput, connection counts, and performance data |
+| 🎮 **Custom Protocols** | Socket and datagram handlers for implementing any protocol in TypeScript |
+| 📊 **Live Metrics** | Real-time throughput, connection counts, UDP sessions, and performance data |
 | 🔧 **Dynamic Management** | Add/remove ports and routes at runtime without restarts |
 | 🔄 **PROXY Protocol** | Full PROXY protocol v1/v2 support for preserving client information |
 | 💾 **Consumer Cert Storage** | Bring your own persistence — SmartProxy never writes certs to disk |
@@ -89,7 +90,7 @@ SmartProxy uses a powerful **match/action** pattern that makes routing predictab
 ```
 
 Every route consists of:
-- **Match** — What traffic to capture (ports, domains, paths, protocol, IPs, headers)
+- **Match** — What traffic to capture (ports, domains, paths, transport, protocol, IPs, headers)
 - **Action** — What to do with it (`forward` or `socket-handler`)
 - **Security** (optional) — IP allow/block lists, rate limits, authentication
 - **Headers** (optional) — Request/response header manipulation with template variables
@@ -197,7 +198,7 @@ apiRoute = addRateLimiting(apiRoute, {
 const proxy = new SmartProxy({ routes: [apiRoute] });
 ```
 
-### 🎮 Custom Protocol Handler
+### 🎮 Custom Protocol Handler (TCP)
 
 SmartProxy lets you implement any protocol with full socket control. Routes with JavaScript socket handlers are automatically relayed from the Rust engine back to your TypeScript code:
 
@@ -247,6 +248,98 @@ const proxy = new SmartProxy({ routes: [echoRoute, customRoute] });
 | `SocketHandlers.httpBlock(status, message)` | HTTP block response |
 | `SocketHandlers.block(message)` | Block with optional message |
 
+### 📡 UDP Datagram Handler
+
+Handle raw UDP datagrams with custom TypeScript logic — perfect for DNS, game servers, IoT protocols, or any UDP-based service:
+
+```typescript
+import { SmartProxy } from '@push.rocks/smartproxy';
+import type { IRouteConfig, TDatagramHandler, IDatagramInfo } from '@push.rocks/smartproxy';
+
+// Custom UDP echo handler
+const udpHandler: TDatagramHandler = (datagram, info, reply) => {
+  console.log(`UDP from ${info.sourceIp}:${info.sourcePort} on port ${info.destPort}`);
+  reply(datagram); // Echo it back
+};
+
+const proxy = new SmartProxy({
+  routes: [{
+    name: 'udp-echo',
+    match: {
+      ports: 5353,
+      transport: 'udp'        // 👈 Listen for UDP datagrams
+    },
+    action: {
+      type: 'socket-handler',
+      datagramHandler: udpHandler,  // 👈 Process each datagram
+      udp: {
+        sessionTimeout: 60000,     // Session idle timeout (ms)
+        maxSessionsPerIP: 100,
+        maxDatagramSize: 65535
+      }
+    }
+  }]
+});
+
+await proxy.start();
+```
+
+### 📡 QUIC / HTTP3 Forwarding
+
+Forward QUIC traffic to backends with optional protocol translation (e.g., receive QUIC, forward as TCP/HTTP1):
+
+```typescript
+import { SmartProxy } from '@push.rocks/smartproxy';
+import type { IRouteConfig } from '@push.rocks/smartproxy';
+
+const quicRoute: IRouteConfig = {
+  name: 'quic-to-backend',
+  match: {
+    ports: 443,
+    transport: 'udp',
+    protocol: 'quic'           // 👈 Match QUIC protocol
+  },
+  action: {
+    type: 'forward',
+    targets: [{
+      host: 'backend-server',
+      port: 8443,
+      backendTransport: 'tcp'  // 👈 Translate QUIC → TCP for backend
+    }],
+    udp: {
+      quic: {
+        enableHttp3: true,
+        maxIdleTimeout: 30000,
+        maxConcurrentBidiStreams: 100,
+        altSvcPort: 443,       // Advertise in Alt-Svc header
+        altSvcMaxAge: 86400
+      }
+    }
+  }
+};
+
+const proxy = new SmartProxy({ routes: [quicRoute] });
+```
+
+### 🔁 Dual-Stack TCP + UDP Route
+
+Listen on both TCP and UDP with a single route — handle each transport with its own handler:
+
+```typescript
+const dualStackRoute: IRouteConfig = {
+  name: 'dual-stack-dns',
+  match: {
+    ports: 53,
+    transport: 'all'  // 👈 Listen on both TCP and UDP
+  },
+  action: {
+    type: 'socket-handler',
+    socketHandler: handleTcpDns,      // 👈 TCP connections
+    datagramHandler: handleUdpDns,    // 👈 UDP datagrams
+  }
+};
+```
+
 ### ⚡ High-Performance NFTables Forwarding
 
 For ultra-low latency on Linux, use kernel-level forwarding (requires root):
@@ -419,6 +512,10 @@ console.log(`Bytes in: ${metrics.totals.bytesIn()}`);
 console.log(`Requests/sec: ${metrics.requests.perSecond()}`);
 console.log(`Throughput in: ${metrics.throughput.instant().in} bytes/sec`);
 
+// UDP metrics
+console.log(`UDP sessions: ${metrics.udp.activeSessions()}`);
+console.log(`Datagrams in: ${metrics.udp.datagramsIn()}`);
+
 // Get detailed statistics from the Rust engine
 const stats = await proxy.getStatistics();
 
@@ -545,7 +642,7 @@ SmartProxy uses a hybrid **Rust + TypeScript** architecture:
 ```
 ┌─────────────────────────────────────────────────────┐
 │                  Your Application                    │
-│     (TypeScript — routes, config, socket handlers)   │
+│     (TypeScript — routes, config, handlers)          │
 └──────────────────┬──────────────────────────────────┘
                    │  IPC (JSON over stdin/stdout)
 ┌──────────────────▼──────────────────────────────────┐
@@ -556,22 +653,23 @@ SmartProxy uses a hybrid **Rust + TypeScript** architecture:
 │  │         │ │  Proxy   │ │         │ │          │  │
 │  └─────────┘ └─────────┘ └─────────┘ └──────────┘  │
 │  ┌─────────┐ ┌─────────┐ ┌─────────┐ ┌──────────┐  │
-│  │ Security│ │ Metrics  │ │ Connec- │ │ NFTables │  │
-│  │ Enforce │ │ Collect  │ │  tion   │ │  Mgr     │  │
-│  │         │ │          │ │ Tracker │ │          │  │
+│  │   UDP   │ │ Security│ │ Metrics  │ │ NFTables │  │
+│  │  QUIC   │ │ Enforce │ │ Collect  │ │  Mgr     │  │
+│  │  HTTP/3 │ │         │ │          │ │          │  │
 │  └─────────┘ └─────────┘ └─────────┘ └──────────┘  │
 └──────────────────┬──────────────────────────────────┘
                    │  Unix Socket Relay
 ┌──────────────────▼──────────────────────────────────┐
-│       TypeScript Socket Handler Server               │
-│  (for JS-defined socket handlers & dynamic routes)   │
+│   TypeScript Socket & Datagram Handler Servers       │
+│  (for JS socket handlers, datagram handlers,         │
+│   and dynamic routes)                                │
 └─────────────────────────────────────────────────────┘
 ```
 
-- **Rust Engine** handles all networking, TLS, HTTP proxying, connection management, security, and metrics
-- **TypeScript** provides the npm API, configuration types, route helpers, validation, and socket handler callbacks
+- **Rust Engine** handles all networking: TCP, UDP, TLS, QUIC, HTTP proxying, connection management, security, and metrics
+- **TypeScript** provides the npm API, configuration types, route helpers, validation, and handler callbacks
 - **IPC** — The TypeScript wrapper uses JSON commands/events over stdin/stdout to communicate with the Rust binary
-- **Socket Relay** — A Unix domain socket server for routes requiring TypeScript-side handling (socket handlers, dynamic host/port functions)
+- **Socket/Datagram Relay** — Unix domain socket servers for routes requiring TypeScript-side handling (socket handlers, datagram handlers, dynamic host/port functions)
 
 ## 🎯 Route Configuration Reference
 
@@ -579,22 +677,26 @@ SmartProxy uses a hybrid **Rust + TypeScript** architecture:
 
 ```typescript
 interface IRouteMatch {
-  ports: number | number[] | Array<{ from: number; to: number }>;  // Required — port(s) to listen on
-  domains?: string | string[];         // 'example.com', '*.example.com'
-  path?: string;                       // '/api/*', '/users/:id'
-  clientIp?: string[];                 // ['10.0.0.0/8', '192.168.*']
-  tlsVersion?: string[];               // ['TLSv1.2', 'TLSv1.3']
+  ports: TPortRange;                     // Required — port(s) to listen on
+  transport?: 'tcp' | 'udp' | 'all';    // Transport protocol (default: 'tcp')
+  domains?: string | string[];           // 'example.com', '*.example.com'
+  path?: string;                         // '/api/*', '/users/:id'
+  clientIp?: string[];                   // ['10.0.0.0/8', '192.168.*']
+  tlsVersion?: string[];                 // ['TLSv1.2', 'TLSv1.3']
   headers?: Record<string, string | RegExp>;  // Match by HTTP headers
-  protocol?: 'http' | 'tcp';          // Match specific protocol ('http' includes h2 + WebSocket upgrades)
+  protocol?: 'http' | 'tcp' | 'udp' | 'quic' | 'http3';  // Application-layer protocol
 }
+
+// Port range supports single numbers, arrays, and ranges
+type TPortRange = number | Array<number | { from: number; to: number }>;
 ```
 
 ### Action Types
 
 | Type | Description |
 |------|-------------|
-| `forward` | Proxy to one or more backend targets (with optional TLS, WebSocket, load balancing) |
-| `socket-handler` | Custom socket handling function in TypeScript |
+| `forward` | Proxy to one or more backend targets (with optional TLS, WebSocket, load balancing, UDP/QUIC) |
+| `socket-handler` | Custom socket/datagram handling function in TypeScript |
 
 ### Target Options
 
@@ -602,14 +704,15 @@ interface IRouteMatch {
 interface IRouteTarget {
   host: string | string[] | ((context: IRouteContext) => string | string[]);
   port: number | 'preserve' | ((context: IRouteContext) => number);
-  tls?: IRouteTls;           // Per-target TLS override
-  priority?: number;          // Target priority
-  match?: ITargetMatch;       // Sub-match within a route (by port, path, headers, method)
+  tls?: IRouteTls;                  // Per-target TLS override
+  priority?: number;                // Target priority
+  match?: ITargetMatch;             // Sub-match within a route (by port, path, headers, method)
   websocket?: IRouteWebSocket;
   loadBalancing?: IRouteLoadBalancing;
   sendProxyProtocol?: boolean;
   headers?: IRouteHeaders;
   advanced?: IRouteAdvanced;
+  backendTransport?: 'tcp' | 'udp'; // Backend transport (e.g., receive QUIC, forward as TCP)
 }
 ```
 
@@ -666,6 +769,27 @@ interface IRouteLoadBalancing {
 }
 ```
 
+### UDP & QUIC Options
+
+```typescript
+interface IRouteUdp {
+  sessionTimeout?: number;       // Idle timeout per UDP session (ms, default: 60000)
+  maxSessionsPerIP?: number;     // Max concurrent sessions per IP (default: 1000)
+  maxDatagramSize?: number;      // Max datagram size in bytes (default: 65535)
+  quic?: IRouteQuic;
+}
+
+interface IRouteQuic {
+  maxIdleTimeout?: number;                // QUIC idle timeout (ms, default: 30000)
+  maxConcurrentBidiStreams?: number;       // Max bidi streams (default: 100)
+  maxConcurrentUniStreams?: number;        // Max uni streams (default: 100)
+  enableHttp3?: boolean;                  // Enable HTTP/3 (default: false)
+  altSvcPort?: number;                    // Port for Alt-Svc header
+  altSvcMaxAge?: number;                  // Alt-Svc max age in seconds (default: 86400)
+  initialCongestionWindow?: number;       // Initial congestion window (bytes)
+}
+```
+
 ## 🛠️ Helper Functions Reference
 
 All helpers are fully typed and return `IRouteConfig` or `IRouteConfig[]`:
@@ -689,7 +813,7 @@ import {
   createWebSocketRoute,            // WebSocket-enabled route
 
   // Custom Protocols
-  createSocketHandlerRoute,        // Custom socket handler
+  createSocketHandlerRoute,        // Custom TCP socket handler
   SocketHandlers,                  // Pre-built handlers (echo, proxy, block, etc.)
 
   // NFTables (Linux, requires root)
@@ -718,6 +842,8 @@ import {
 } from '@push.rocks/smartproxy';
 ```
 
+> **Tip:** For UDP datagram handler routes or QUIC/HTTP3 routes, construct `IRouteConfig` objects directly — there are no helper functions for these yet. See the [UDP Datagram Handler](#-udp-datagram-handler) and [QUIC / HTTP3 Forwarding](#-quic--http3-forwarding) examples above.
+
 ## 📖 API Documentation
 
 ### SmartProxy Class
@@ -753,6 +879,8 @@ class SmartProxy extends EventEmitter {
 
   // Events
   on(event: 'error', handler: (err: Error) => void): this;
+  on(event: 'certificate-issued', handler: (ev: ICertificateIssuedEvent) => void): this;
+  on(event: 'certificate-failed', handler: (ev: ICertificateFailedEvent) => void): this;
 }
 ```
 
@@ -775,6 +903,8 @@ interface ISmartProxyOptions {
   // Custom certificate provisioning
   certProvisionFunction?: (domain: string) => Promise<ICert | 'http01'>;
   certProvisionFallbackToAcme?: boolean;    // Fall back to ACME on failure (default: true)
+  certProvisionTimeout?: number;            // Timeout per provision call (ms)
+  certProvisionConcurrency?: number;        // Max concurrent provisions
 
   // Consumer-managed certificate persistence (see "Consumer-Managed Certificate Storage")
   certStore?: ISmartProxyCertStore;
@@ -782,6 +912,9 @@ interface ISmartProxyOptions {
   // Self-signed fallback
   disableDefaultCert?: boolean;             // Disable '*' self-signed fallback (default: false)
 
+  // Rust binary path override
+  rustBinaryPath?: string;                  // Custom path to the Rust proxy binary
+
   // Global defaults
   defaults?: {
     target?: { host: string; port: number };
@@ -868,11 +1001,22 @@ metrics.requests.perSecond();              // Requests per second
 metrics.requests.perMinute();              // Requests per minute
 metrics.requests.total();                  // Total requests
 
+// UDP metrics
+metrics.udp.activeSessions();              // Current active UDP sessions
+metrics.udp.totalSessions();              // Total UDP sessions since start
+metrics.udp.datagramsIn();                // Datagrams received
+metrics.udp.datagramsOut();               // Datagrams sent
+
 // Cumulative totals
 metrics.totals.bytesIn();                  // Total bytes received
 metrics.totals.bytesOut();                 // Total bytes sent
 metrics.totals.connections();              // Total connections
 
+// Backend metrics
+metrics.backends.byBackend();              // Map<backend, IBackendMetrics>
+metrics.backends.protocols();              // Map<backend, protocol>
+metrics.backends.topByErrors(10);          // Top N error-prone backends
+
 // Percentiles
 metrics.percentiles.connectionDuration();  // { p50, p95, p99 }
 metrics.percentiles.bytesTransferred();    // { in: { p50, p95, p99 }, out: { p50, p95, p99 } }
@@ -896,11 +1040,12 @@ metrics.percentiles.bytesTransferred();    // { in: { p50, p95, p99 }, out: { p5
 ### Rust Binary Not Found
 
 SmartProxy searches for the Rust binary in this order:
-1. `SMARTPROXY_RUST_BINARY` environment variable
-2. Platform-specific npm package (`@push.rocks/smartproxy-linux-x64`, etc.)
-3. `dist_rust/rustproxy` relative to the package root (built by `tsrust`)
-4. Local dev build (`./rust/target/release/rustproxy`)
-5. System PATH (`rustproxy`)
+1. `rustBinaryPath` option in `ISmartProxyOptions`
+2. `SMARTPROXY_RUST_BINARY` environment variable
+3. Platform-specific npm package (`@push.rocks/smartproxy-linux-x64`, etc.)
+4. `dist_rust/rustproxy` relative to the package root (built by `tsrust`)
+5. Local dev build (`./rust/target/release/rustproxy`)
+6. System PATH (`rustproxy`)
 
 ### Performance Tuning
 - ✅ Use NFTables forwarding for high-traffic routes (Linux only)

rust/crates/rustproxy-http/src/h3_service.rs

@@ -4,11 +4,14 @@
 //! and forwards them to backends using the same routing and pool infrastructure
 //! as the HTTP/1+2 proxy.
 
+use std::pin::Pin;
 use std::sync::Arc;
+use std::task::{Context, Poll};
 use std::time::Duration;
 
 use arc_swap::ArcSwap;
 use bytes::{Buf, Bytes};
+use http_body::Frame;
 use tracing::{debug, warn};
 
 use rustproxy_config::{RouteConfig, TransportProtocol};
@@ -165,15 +168,6 @@ async fn handle_h3_request(
     let backend_port = target.port.resolve(port);
     let backend_addr = format!("{}:{}", backend_host, backend_port);
 
-    // Read request body
-    let mut body_data = Vec::new();
-    while let Some(mut chunk) = stream.recv_data().await
-        .map_err(|e| anyhow::anyhow!("Failed to read H3 request body: {}", e))?
-    {
-        body_data.extend_from_slice(chunk.chunk());
-        chunk.advance(chunk.remaining());
-    }
-
     // Connect to backend via TCP HTTP/1.1 with timeout
     let tcp_stream = tokio::time::timeout(
         connect_timeout,
@@ -194,11 +188,37 @@ async fn handle_h3_request(
         }
     });
 
-    let body = http_body_util::Full::new(Bytes::from(body_data));
+    // Stream request body from H3 client to backend via an mpsc channel.
+    // This avoids buffering the entire request body in memory.
+    let (body_tx, body_rx) = tokio::sync::mpsc::channel::<Bytes>(4);
+    let total_bytes_in = Arc::new(std::sync::atomic::AtomicU64::new(0));
+    let total_bytes_in_writer = Arc::clone(&total_bytes_in);
+
+    // Spawn the H3 body reader task
+    let body_reader = tokio::spawn(async move {
+        while let Ok(Some(mut chunk)) = stream.recv_data().await {
+            let data = Bytes::copy_from_slice(chunk.chunk());
+            total_bytes_in_writer.fetch_add(data.len() as u64, std::sync::atomic::Ordering::Relaxed);
+            chunk.advance(chunk.remaining());
+            if body_tx.send(data).await.is_err() {
+                break;
+            }
+        }
+        stream
+    });
+
+    // Create a body that polls from the mpsc receiver
+    let body = H3RequestBody { receiver: body_rx };
     let backend_req = build_backend_request(&method, &backend_addr, &path, &host, &request, body)?;
+
     let response = sender.send_request(backend_req).await
         .map_err(|e| anyhow::anyhow!("Backend request failed: {}", e))?;
 
+    // Await the body reader to get the stream back
+    let mut stream = body_reader.await
+        .map_err(|e| anyhow::anyhow!("Body reader task failed: {}", e))?;
+    let total_bytes_in = total_bytes_in.load(std::sync::atomic::Ordering::Relaxed);
+
     // Build H3 response
     let status = response.status();
     let mut h3_response = hyper::Response::builder().status(status);
@@ -252,7 +272,7 @@ async fn handle_h3_request(
 
     // Record metrics
     let route_id = route.name.as_deref().or(route.id.as_deref());
-    metrics.record_bytes(0, total_bytes_out, route_id, Some(client_ip));
+    metrics.record_bytes(total_bytes_in, total_bytes_out, route_id, Some(client_ip));
 
     // Finish the stream
     stream.finish().await
@@ -262,14 +282,14 @@ async fn handle_h3_request(
 }
 
 /// Build an HTTP/1.1 backend request from the H3 frontend request.
-fn build_backend_request(
+fn build_backend_request<B>(
     method: &hyper::Method,
     backend_addr: &str,
     path: &str,
     host: &str,
     original_request: &hyper::Request<()>,
-    body: http_body_util::Full<Bytes>,
-) -> anyhow::Result<hyper::Request<http_body_util::Full<Bytes>>> {
+    body: B,
+) -> anyhow::Result<hyper::Request<B>> {
     let mut req = hyper::Request::builder()
         .method(method)
         .uri(format!("http://{}{}", backend_addr, path))
@@ -286,3 +306,27 @@ fn build_backend_request(
     req.body(body)
         .map_err(|e| anyhow::anyhow!("Failed to build backend request: {}", e))
 }
+
+/// A streaming request body backed by an mpsc channel receiver.
+///
+/// Implements `http_body::Body` so hyper can poll chunks as they arrive
+/// from the H3 client, avoiding buffering the entire request body in memory.
+struct H3RequestBody {
+    receiver: tokio::sync::mpsc::Receiver<Bytes>,
+}
+
+impl http_body::Body for H3RequestBody {
+    type Data = Bytes;
+    type Error = hyper::Error;
+
+    fn poll_frame(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Option<Result<Frame<Self::Data>, Self::Error>>> {
+        match self.receiver.poll_recv(cx) {
+            Poll::Ready(Some(data)) => Poll::Ready(Some(Ok(Frame::data(data)))),
+            Poll::Ready(None) => Poll::Ready(None),
+            Poll::Pending => Poll::Pending,
+        }
+    }
+}

rust/crates/rustproxy-passthrough/src/quic_handler.rs

@@ -20,7 +20,6 @@ use rustproxy_metrics::MetricsCollector;
 use rustproxy_routing::{MatchContext, RouteManager};
 
 use crate::connection_tracker::ConnectionTracker;
-use crate::forwarder::ForwardMetricsCtx;
 
 /// Create a QUIC server endpoint on the given port with the provided TLS config.
 ///
@@ -116,7 +115,7 @@ pub async fn quic_accept_loop(
         let cancel = cancel.child_token();
 
         tokio::spawn(async move {
-            match handle_quic_connection(incoming, route, port, &metrics, &cancel).await {
+            match handle_quic_connection(incoming, route, port, Arc::clone(&metrics), &cancel).await {
                 Ok(()) => debug!("QUIC connection from {} completed", remote_addr),
                 Err(e) => debug!("QUIC connection from {} error: {}", remote_addr, e),
             }
@@ -138,7 +137,7 @@ async fn handle_quic_connection(
     incoming: quinn::Incoming,
     route: RouteConfig,
     port: u16,
-    metrics: &MetricsCollector,
+    metrics: Arc<MetricsCollector>,
     cancel: &CancellationToken,
 ) -> anyhow::Result<()> {
     let connection = incoming.await?;
@@ -155,7 +154,7 @@ async fn handle_quic_connection(
         // Phase 5: dispatch to H3ProxyService
         // For now, log and accept streams for basic handling
         debug!("HTTP/3 enabled for route {:?}, dispatching to H3 handler", route.name);
-        handle_h3_connection(connection, route, port, metrics, cancel).await
+        handle_h3_connection(connection, route, port, &metrics, cancel).await
     } else {
         // Non-HTTP3 QUIC: bidirectional stream forwarding to TCP backend
         handle_quic_stream_forwarding(connection, route, port, metrics, cancel).await
@@ -171,11 +170,12 @@ async fn handle_quic_stream_forwarding(
     connection: quinn::Connection,
     route: RouteConfig,
     port: u16,
-    _metrics: &MetricsCollector,
+    metrics: Arc<MetricsCollector>,
     cancel: &CancellationToken,
 ) -> anyhow::Result<()> {
     let remote_addr = connection.remote_address();
     let route_id = route.name.as_deref().or(route.id.as_deref());
+    let metrics_arc = metrics;
 
     // Resolve backend target
     let target = route.action.targets.as_ref()
@@ -203,11 +203,8 @@ async fn handle_quic_stream_forwarding(
 
         let backend_addr = backend_addr.clone();
         let ip_str = remote_addr.ip().to_string();
-        let _fwd_ctx = ForwardMetricsCtx {
-            collector: Arc::new(MetricsCollector::new()), // TODO: share real metrics
-            route_id: route_id.map(|s| s.to_string()),
-            source_ip: Some(ip_str),
-        };
+        let stream_metrics = Arc::clone(&metrics_arc);
+        let stream_route_id = route_id.map(|s| s.to_string());
 
         // Spawn a task for each QUIC stream → TCP bidirectional forwarding
         tokio::spawn(async move {
@@ -217,6 +214,11 @@ async fn handle_quic_stream_forwarding(
                 &backend_addr,
             ).await {
                 Ok((bytes_in, bytes_out)) => {
+                    stream_metrics.record_bytes(
+                        bytes_in, bytes_out,
+                        stream_route_id.as_deref(),
+                        Some(&ip_str),
+                    );
                     debug!("QUIC stream forwarded: {}B in, {}B out", bytes_in, bytes_out);
                 }
                 Err(e) => {

rust/crates/rustproxy-passthrough/src/udp_listener.rs

@@ -8,12 +8,12 @@ use std::net::SocketAddr;
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
 
-use tokio::io::AsyncWriteExt;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
 
 use arc_swap::ArcSwap;
 use tokio::net::UdpSocket;
 use tokio::task::JoinHandle;
-use tokio::sync::RwLock;
+use tokio::sync::{Mutex, RwLock};
 use tokio_util::sync::CancellationToken;
 use tracing::{debug, error, info, warn};
 
@@ -40,6 +40,19 @@ pub struct UdpListenerManager {
     cancel_token: CancellationToken,
     /// Unix socket path for datagram handler relay
     datagram_handler_relay: Arc<RwLock<Option<String>>>,
+    /// Persistent write half of the relay connection
+    relay_writer: Arc<Mutex<Option<tokio::net::unix::OwnedWriteHalf>>>,
+    /// Cancel token for the current relay reply reader task
+    relay_reader_cancel: Option<CancellationToken>,
+}
+
+impl Drop for UdpListenerManager {
+    fn drop(&mut self) {
+        self.cancel_token.cancel();
+        for (_, handle) in self.listeners.drain() {
+            handle.abort();
+        }
+    }
 }
 
 impl UdpListenerManager {
@@ -57,6 +70,8 @@ impl UdpListenerManager {
             session_table: Arc::new(UdpSessionTable::new()),
             cancel_token,
             datagram_handler_relay: Arc::new(RwLock::new(None)),
+            relay_writer: Arc::new(Mutex::new(None)),
+            relay_reader_cancel: None,
         }
     }
 
@@ -126,6 +141,7 @@ impl UdpListenerManager {
             Arc::clone(&self.conn_tracker),
             Arc::clone(&self.session_table),
             Arc::clone(&self.datagram_handler_relay),
+            Arc::clone(&self.relay_writer),
             self.cancel_token.child_token(),
         ));
 
@@ -165,16 +181,49 @@ impl UdpListenerManager {
             self.session_table.session_count());
     }
 
-    /// Set the datagram handler relay socket path.
-    pub async fn set_datagram_handler_relay(&self, path: String) {
-        let mut relay = self.datagram_handler_relay.write().await;
-        *relay = Some(path);
+    /// Set the datagram handler relay socket path and establish connection.
+    pub async fn set_datagram_handler_relay(&mut self, path: String) {
+        // Cancel previous relay reader task if any
+        if let Some(old_cancel) = self.relay_reader_cancel.take() {
+            old_cancel.cancel();
+        }
+
+        // Store the path
+        {
+            let mut relay = self.datagram_handler_relay.write().await;
+            *relay = Some(path.clone());
+        }
+
+        // Connect to the Unix socket
+        match tokio::net::UnixStream::connect(&path).await {
+            Ok(stream) => {
+                let (read_half, write_half) = stream.into_split();
+
+                // Store write half for sending datagrams
+                {
+                    let mut writer = self.relay_writer.lock().await;
+                    *writer = Some(write_half);
+                }
+
+                // Spawn reply reader — reads length-prefixed JSON replies from TS
+                // and sends them back to clients via the listener sockets
+                let cancel = self.cancel_token.child_token();
+                self.relay_reader_cancel = Some(cancel.clone());
+                tokio::spawn(Self::relay_reply_reader(read_half, cancel));
+
+                info!("Datagram handler relay connected to {}", path);
+            }
+            Err(e) => {
+                error!("Failed to connect datagram handler relay to {}: {}", path, e);
+            }
+        }
     }
 
     /// Start periodic session cleanup task.
     fn start_cleanup_task(&self) {
         let session_table = Arc::clone(&self.session_table);
         let metrics = Arc::clone(&self.metrics);
+        let conn_tracker = Arc::clone(&self.conn_tracker);
         let cancel = self.cancel_token.child_token();
         let route_manager = Arc::clone(&self.route_manager);
 
@@ -188,7 +237,7 @@ impl UdpListenerManager {
                         // or default 60s if none configured)
                         let rm = route_manager.load();
                         let timeout_ms = Self::get_min_session_timeout(&rm);
-                        let removed = session_table.cleanup_idle(timeout_ms, &metrics);
+                        let removed = session_table.cleanup_idle(timeout_ms, &metrics, &conn_tracker);
                         if removed > 0 {
                             debug!("UDP session cleanup: removed {} idle sessions, {} remaining",
                                 removed, session_table.session_count());
@@ -213,7 +262,8 @@ impl UdpListenerManager {
         metrics: Arc<MetricsCollector>,
         conn_tracker: Arc<ConnectionTracker>,
         session_table: Arc<UdpSessionTable>,
-        datagram_handler_relay: Arc<RwLock<Option<String>>>,
+        _datagram_handler_relay: Arc<RwLock<Option<String>>>,
+        relay_writer: Arc<Mutex<Option<tokio::net::unix::OwnedWriteHalf>>>,
         cancel: CancellationToken,
     ) {
         // Use a reasonably large buffer; actual max is per-route but we need a single buffer
@@ -264,21 +314,16 @@ impl UdpListenerManager {
             let route = route_match.route;
             let route_id = route.name.as_deref().or(route.id.as_deref());
 
-            // Socket handler routes → relay datagram to TS via Unix socket
+            // Socket handler routes → relay datagram to TS via persistent Unix socket
             if route.action.action_type == RouteActionType::SocketHandler {
-                let relay_path = datagram_handler_relay.read().await;
-                if let Some(ref path) = *relay_path {
-                    if let Err(e) = Self::relay_datagram_to_ts(
-                        path,
-                        route_id.unwrap_or("unknown"),
-                        &client_addr,
-                        port,
-                        datagram,
-                    ).await {
-                        debug!("Failed to relay UDP datagram to TS: {}", e);
-                    }
-                } else {
-                    debug!("UDP datagram handler relay not configured for route {:?}", route_id);
+                if let Err(e) = Self::relay_datagram_via_writer(
+                    &relay_writer,
+                    route_id.unwrap_or("unknown"),
+                    &client_addr,
+                    port,
+                    datagram,
+                ).await {
+                    debug!("Failed to relay UDP datagram to TS: {}", e);
                 }
                 continue;
             }
@@ -441,10 +486,9 @@ impl UdpListenerManager {
         }
     }
 
-    /// Relay a UDP datagram to the TypeScript handler via Unix socket.
-    /// Uses length-prefixed JSON framing: [4-byte BE length][JSON payload]
-    async fn relay_datagram_to_ts(
-        relay_path: &str,
+    /// Send a datagram to TS via the persistent relay writer.
+    async fn relay_datagram_via_writer(
+        writer: &Mutex<Option<tokio::net::unix::OwnedWriteHalf>>,
         route_key: &str,
         client_addr: &SocketAddr,
         dest_port: u16,
@@ -463,8 +507,9 @@ impl UdpListenerManager {
         });
         let json = serde_json::to_vec(&msg)?;
 
-        // Connect to relay (one-shot for now; persistent connection optimization deferred)
-        let mut stream = tokio::net::UnixStream::connect(relay_path).await?;
+        let mut guard = writer.lock().await;
+        let stream = guard.as_mut()
+            .ok_or_else(|| anyhow::anyhow!("Datagram relay not connected"))?;
 
         // Length-prefixed frame
         let len_bytes = (json.len() as u32).to_be_bytes();
@@ -474,4 +519,101 @@ impl UdpListenerManager {
 
         Ok(())
     }
+
+    /// Background task reading reply frames from the TS datagram handler.
+    /// Parses replies and sends them back to the original client via UDP.
+    async fn relay_reply_reader(
+        mut reader: tokio::net::unix::OwnedReadHalf,
+        cancel: CancellationToken,
+    ) {
+        use base64::Engine;
+
+        let mut len_buf = [0u8; 4];
+        loop {
+            // Read length prefix
+            let read_result = tokio::select! {
+                _ = cancel.cancelled() => break,
+                result = reader.read_exact(&mut len_buf) => result,
+            };
+
+            match read_result {
+                Ok(_) => {}
+                Err(e) => {
+                    debug!("Datagram relay reader closed: {}", e);
+                    break;
+                }
+            }
+
+            let frame_len = u32::from_be_bytes(len_buf) as usize;
+            if frame_len > 10 * 1024 * 1024 {
+                error!("Datagram relay frame too large: {} bytes", frame_len);
+                break;
+            }
+
+            let mut frame_buf = vec![0u8; frame_len];
+            match reader.read_exact(&mut frame_buf).await {
+                Ok(_) => {}
+                Err(e) => {
+                    debug!("Datagram relay reader frame error: {}", e);
+                    break;
+                }
+            }
+
+            // Parse the reply JSON
+            let reply: serde_json::Value = match serde_json::from_slice(&frame_buf) {
+                Ok(v) => v,
+                Err(e) => {
+                    debug!("Datagram relay reply parse error: {}", e);
+                    continue;
+                }
+            };
+
+            if reply.get("type").and_then(|v| v.as_str()) != Some("reply") {
+                continue;
+            }
+
+            let source_ip = reply.get("sourceIp").and_then(|v| v.as_str()).unwrap_or("");
+            let source_port = reply.get("sourcePort").and_then(|v| v.as_u64()).unwrap_or(0) as u16;
+            let dest_port = reply.get("destPort").and_then(|v| v.as_u64()).unwrap_or(0) as u16;
+            let payload_b64 = reply.get("payloadBase64").and_then(|v| v.as_str()).unwrap_or("");
+
+            let payload = match base64::engine::general_purpose::STANDARD.decode(payload_b64) {
+                Ok(p) => p,
+                Err(e) => {
+                    debug!("Datagram relay reply base64 decode error: {}", e);
+                    continue;
+                }
+            };
+
+            let client_addr: SocketAddr = match format!("{}:{}", source_ip, source_port).parse() {
+                Ok(a) => a,
+                Err(e) => {
+                    debug!("Datagram relay reply address parse error: {}", e);
+                    continue;
+                }
+            };
+
+            // Send the reply back to the client via a temporary UDP socket bound to the dest_port
+            // We need the listener socket for this port. For simplicity, use a fresh socket.
+            let reply_socket = match UdpSocket::bind(format!("0.0.0.0:{}", dest_port)).await {
+                Ok(s) => s,
+                Err(_) => {
+                    // Port already bound by the listener — use unbound socket
+                    match UdpSocket::bind("0.0.0.0:0").await {
+                        Ok(s) => s,
+                        Err(e) => {
+                            debug!("Failed to create reply socket: {}", e);
+                            continue;
+                        }
+                    }
+                }
+            };
+
+            if let Err(e) = reply_socket.send_to(&payload, client_addr).await {
+                debug!("Failed to send datagram reply to {}: {}", client_addr, e);
+            }
+        }
+
+        debug!("Datagram relay reply reader stopped");
+    }
 }

rust/crates/rustproxy-passthrough/src/udp_session.rs

@@ -18,6 +18,8 @@ use tracing::debug;
 
 use rustproxy_metrics::MetricsCollector;
 
+use crate::connection_tracker::ConnectionTracker;
+
 /// A single UDP session (flow).
 pub struct UdpSession {
     /// Socket bound to ephemeral port, connected to backend
@@ -165,6 +167,7 @@ impl UdpSessionTable {
         &self,
         timeout_ms: u64,
         metrics: &MetricsCollector,
+        conn_tracker: &ConnectionTracker,
     ) -> usize {
         let now_ms = self.elapsed_ms();
         let mut removed = 0;
@@ -185,6 +188,7 @@ impl UdpSessionTable {
                     session.client_addr, key.1,
                     now_ms.saturating_sub(session.last_activity.load(Ordering::Relaxed))
                 );
+                conn_tracker.connection_closed(&session.source_ip);
                 metrics.connection_closed(
                     session.route_id.as_deref(),
                     Some(&session.source_ip.to_string()),

rust/crates/rustproxy/src/lib.rs

@@ -1008,7 +1008,7 @@ impl RustProxy {
     /// Set the Unix domain socket path for relaying UDP datagrams to TypeScript datagramHandler callbacks.
     pub async fn set_datagram_handler_relay_path(&mut self, path: Option<String>) {
         info!("Datagram handler relay path set to: {:?}", path);
-        if let Some(ref udp_mgr) = self.udp_listener_manager {
+        if let Some(ref mut udp_mgr) = self.udp_listener_manager {
             if let Some(ref p) = path {
                 udp_mgr.set_datagram_handler_relay(p.clone()).await;
             }

test/test.datagram-handler.ts

@@ -0,0 +1,125 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as dgram from 'dgram';
+import { SmartProxy } from '../ts/index.js';
+import type { TDatagramHandler, IDatagramInfo } from '../ts/index.js';
+import { findFreePorts, assertPortsFree } from './helpers/port-allocator.js';
+
+let smartProxy: SmartProxy;
+let PROXY_PORT: number;
+
+// Helper: send a single UDP datagram and wait for a response
+function sendDatagram(port: number, msg: string, timeoutMs = 5000): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const client = dgram.createSocket('udp4');
+    const timeout = setTimeout(() => {
+      client.close();
+      reject(new Error(`UDP response timeout after ${timeoutMs}ms`));
+    }, timeoutMs);
+    client.send(Buffer.from(msg), port, '127.0.0.1');
+    client.on('message', (data) => {
+      clearTimeout(timeout);
+      client.close();
+      resolve(data.toString());
+    });
+    client.on('error', (err) => {
+      clearTimeout(timeout);
+      client.close();
+      reject(err);
+    });
+  });
+}
+
+tap.test('setup: start SmartProxy with datagramHandler', async () => {
+  [PROXY_PORT] = await findFreePorts(1);
+
+  const handler: TDatagramHandler = (datagram, info, reply) => {
+    reply(Buffer.from(`Handled: ${datagram.toString()}`));
+  };
+
+  smartProxy = new SmartProxy({
+    routes: [
+      {
+        name: 'dgram-handler-test',
+        match: {
+          ports: PROXY_PORT,
+          transport: 'udp' as const,
+        },
+        action: {
+          type: 'socket-handler',
+          datagramHandler: handler,
+        },
+      },
+    ],
+    defaults: {
+      security: {
+        ipAllowList: ['127.0.0.1', '::1', '::ffff:127.0.0.1'],
+      },
+    },
+  });
+
+  await smartProxy.start();
+});
+
+tap.test('datagram handler: receives and replies to datagram', async () => {
+  const response = await sendDatagram(PROXY_PORT, 'Hello Handler');
+  expect(response).toEqual('Handled: Hello Handler');
+});
+
+tap.test('datagram handler: async handler works', async () => {
+  // Stop and restart with async handler
+  await smartProxy.stop();
+
+  [PROXY_PORT] = await findFreePorts(1);
+
+  const asyncHandler: TDatagramHandler = async (datagram, info, reply) => {
+    // Simulate async work
+    await new Promise<void>((resolve) => setTimeout(resolve, 10));
+    reply(Buffer.from(`Async: ${datagram.toString()}`));
+  };
+
+  smartProxy = new SmartProxy({
+    routes: [
+      {
+        name: 'dgram-async-handler',
+        match: {
+          ports: PROXY_PORT,
+          transport: 'udp' as const,
+        },
+        action: {
+          type: 'socket-handler',
+          datagramHandler: asyncHandler,
+        },
+      },
+    ],
+    defaults: {
+      security: {
+        ipAllowList: ['127.0.0.1', '::1', '::ffff:127.0.0.1'],
+      },
+    },
+  });
+
+  await smartProxy.start();
+
+  const response = await sendDatagram(PROXY_PORT, 'Test Async');
+  expect(response).toEqual('Async: Test Async');
+});
+
+tap.test('datagram handler: multiple rapid datagrams', async () => {
+  const promises: Promise<string>[] = [];
+  for (let i = 0; i < 5; i++) {
+    promises.push(sendDatagram(PROXY_PORT, `msg-${i}`));
+  }
+
+  const responses = await Promise.all(promises);
+
+  for (let i = 0; i < 5; i++) {
+    expect(responses).toContain(`Async: msg-${i}`);
+  }
+});
+
+tap.test('cleanup: stop SmartProxy', async () => {
+  await smartProxy.stop();
+  await assertPortsFree([PROXY_PORT]);
+});
+
+export default tap.start();

test/test.route-utils.ts

@@ -174,7 +174,7 @@ tap.test('Route Validation - validateRouteAction', async () => {
   const invalidSocketResult = validateRouteAction(invalidSocketAction);
   expect(invalidSocketResult.valid).toBeFalse();
   expect(invalidSocketResult.errors.length).toBeGreaterThan(0);
-  expect(invalidSocketResult.errors[0]).toInclude('Socket handler function is required');
+  expect(invalidSocketResult.errors[0]).toInclude('handler function is required');
 });
 
 tap.test('Route Validation - validateRouteConfig', async () => {

test/test.udp-forwarding.ts

@@ -0,0 +1,142 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as dgram from 'dgram';
+import { SmartProxy } from '../ts/index.js';
+import { findFreePorts, assertPortsFree } from './helpers/port-allocator.js';
+
+let smartProxy: SmartProxy;
+let backendServer: dgram.Socket;
+let PROXY_PORT: number;
+let BACKEND_PORT: number;
+
+// Helper: send a single UDP datagram and wait for a response
+function sendDatagram(port: number, msg: string, timeoutMs = 5000): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const client = dgram.createSocket('udp4');
+    const timeout = setTimeout(() => {
+      client.close();
+      reject(new Error(`UDP response timeout after ${timeoutMs}ms`));
+    }, timeoutMs);
+    client.send(Buffer.from(msg), port, '127.0.0.1');
+    client.on('message', (data) => {
+      clearTimeout(timeout);
+      client.close();
+      resolve(data.toString());
+    });
+    client.on('error', (err) => {
+      clearTimeout(timeout);
+      client.close();
+      reject(err);
+    });
+  });
+}
+
+// Helper: create a UDP echo server
+function createUdpEchoServer(port: number): Promise<dgram.Socket> {
+  return new Promise((resolve) => {
+    const server = dgram.createSocket('udp4');
+    server.on('message', (msg, rinfo) => {
+      server.send(Buffer.from(`Echo: ${msg.toString()}`), rinfo.port, rinfo.address);
+    });
+    server.bind(port, '127.0.0.1', () => resolve(server));
+  });
+}
+
+tap.test('setup: start UDP echo server and SmartProxy', async () => {
+  [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);
+
+  // Start backend UDP echo server
+  backendServer = await createUdpEchoServer(BACKEND_PORT);
+
+  // Start SmartProxy with a UDP forwarding route
+  smartProxy = new SmartProxy({
+    routes: [
+      {
+        name: 'udp-forward-test',
+        match: {
+          ports: PROXY_PORT,
+          transport: 'udp' as const,
+        },
+        action: {
+          type: 'forward',
+          targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
+          udp: {
+            sessionTimeout: 5000,
+          },
+        },
+      },
+    ],
+    defaults: {
+      security: {
+        ipAllowList: ['127.0.0.1', '::1', '::ffff:127.0.0.1'],
+      },
+    },
+  });
+
+  await smartProxy.start();
+});
+
+tap.test('UDP forwarding: basic datagram round-trip', async () => {
+  const response = await sendDatagram(PROXY_PORT, 'Hello UDP');
+  expect(response).toEqual('Echo: Hello UDP');
+});
+
+tap.test('UDP forwarding: multiple datagrams same session', async () => {
+  // Use a single client socket for session reuse
+  const client = dgram.createSocket('udp4');
+  const responses: string[] = [];
+
+  const done = new Promise<void>((resolve, reject) => {
+    const timeout = setTimeout(() => {
+      client.close();
+      reject(new Error('Timeout waiting for 3 responses'));
+    }, 5000);
+
+    client.on('message', (data) => {
+      responses.push(data.toString());
+      if (responses.length === 3) {
+        clearTimeout(timeout);
+        client.close();
+        resolve();
+      }
+    });
+    client.on('error', (err) => {
+      clearTimeout(timeout);
+      client.close();
+      reject(err);
+    });
+  });
+
+  client.send(Buffer.from('msg1'), PROXY_PORT, '127.0.0.1');
+  client.send(Buffer.from('msg2'), PROXY_PORT, '127.0.0.1');
+  client.send(Buffer.from('msg3'), PROXY_PORT, '127.0.0.1');
+
+  await done;
+
+  expect(responses).toContain('Echo: msg1');
+  expect(responses).toContain('Echo: msg2');
+  expect(responses).toContain('Echo: msg3');
+});
+
+tap.test('UDP forwarding: multiple clients', async () => {
+  const [resp1, resp2] = await Promise.all([
+    sendDatagram(PROXY_PORT, 'client1'),
+    sendDatagram(PROXY_PORT, 'client2'),
+  ]);
+
+  expect(resp1).toEqual('Echo: client1');
+  expect(resp2).toEqual('Echo: client2');
+});
+
+tap.test('UDP forwarding: large datagram (1400 bytes)', async () => {
+  const payload = 'X'.repeat(1400);
+  const response = await sendDatagram(PROXY_PORT, payload);
+  expect(response).toEqual(`Echo: ${payload}`);
+});
+
+tap.test('cleanup: stop SmartProxy and backend', async () => {
+  await smartProxy.stop();
+  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
+  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
+});
+
+export default tap.start();

test/test.udp-metrics.ts

@@ -0,0 +1,114 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as dgram from 'dgram';
+import { SmartProxy } from '../ts/index.js';
+import { findFreePorts, assertPortsFree } from './helpers/port-allocator.js';
+
+let smartProxy: SmartProxy;
+let backendServer: dgram.Socket;
+let PROXY_PORT: number;
+let BACKEND_PORT: number;
+
+// Helper: send a single UDP datagram and wait for a response
+function sendDatagram(port: number, msg: string, timeoutMs = 5000): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const client = dgram.createSocket('udp4');
+    const timeout = setTimeout(() => {
+      client.close();
+      reject(new Error(`UDP response timeout after ${timeoutMs}ms`));
+    }, timeoutMs);
+    client.send(Buffer.from(msg), port, '127.0.0.1');
+    client.on('message', (data) => {
+      clearTimeout(timeout);
+      client.close();
+      resolve(data.toString());
+    });
+    client.on('error', (err) => {
+      clearTimeout(timeout);
+      client.close();
+      reject(err);
+    });
+  });
+}
+
+// Helper: create a UDP echo server
+function createUdpEchoServer(port: number): Promise<dgram.Socket> {
+  return new Promise((resolve) => {
+    const server = dgram.createSocket('udp4');
+    server.on('message', (msg, rinfo) => {
+      server.send(Buffer.from(`Echo: ${msg.toString()}`), rinfo.port, rinfo.address);
+    });
+    server.bind(port, '127.0.0.1', () => resolve(server));
+  });
+}
+
+tap.test('setup: start UDP echo server and SmartProxy with metrics', async () => {
+  [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);
+
+  backendServer = await createUdpEchoServer(BACKEND_PORT);
+
+  smartProxy = new SmartProxy({
+    routes: [
+      {
+        name: 'udp-metrics-test',
+        match: {
+          ports: PROXY_PORT,
+          transport: 'udp' as const,
+        },
+        action: {
+          type: 'forward',
+          targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
+          udp: {
+            sessionTimeout: 10000,
+          },
+        },
+      },
+    ],
+    defaults: {
+      security: {
+        ipAllowList: ['127.0.0.1', '::1', '::ffff:127.0.0.1'],
+      },
+    },
+    metrics: {
+      enabled: true,
+      sampleIntervalMs: 1000,
+      retentionSeconds: 60,
+    },
+  });
+
+  await smartProxy.start();
+});
+
+tap.test('UDP metrics: counters increase after traffic', async () => {
+  // Send a few datagrams
+  const resp1 = await sendDatagram(PROXY_PORT, 'metrics-test-1');
+  expect(resp1).toEqual('Echo: metrics-test-1');
+
+  const resp2 = await sendDatagram(PROXY_PORT, 'metrics-test-2');
+  expect(resp2).toEqual('Echo: metrics-test-2');
+
+  // Wait for metrics to propagate and cache to refresh
+  await new Promise<void>((resolve) => setTimeout(resolve, 2000));
+
+  // Get metrics (returns the adapter, need to ensure cache is fresh)
+  const metrics = smartProxy.getMetrics();
+
+  // The udp property reads from the Rust JSON snapshot
+  expect(metrics.udp).toBeDefined();
+  const totalSessions = metrics.udp.totalSessions();
+  const datagramsIn = metrics.udp.datagramsIn();
+  const datagramsOut = metrics.udp.datagramsOut();
+
+  console.log(`UDP metrics: sessions=${totalSessions}, in=${datagramsIn}, out=${datagramsOut}`);
+
+  expect(totalSessions).toBeGreaterThan(0);
+  expect(datagramsIn).toBeGreaterThan(0);
+  expect(datagramsOut).toBeGreaterThan(0);
+});
+
+tap.test('cleanup: stop SmartProxy and backend', async () => {
+  await smartProxy.stop();
+  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
+  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
+});
+
+export default tap.start();

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartproxy',
-  version: '25.13.0',
+  version: '25.15.0',
   description: 'A powerful proxy package with unified route-based configuration for high traffic management. Features include SSL/TLS support, flexible routing patterns, WebSocket handling, advanced security options, and automatic ACME certificate management.'
 }

ts/proxies/smart-proxy/smart-proxy.ts

@@ -303,6 +303,21 @@ export class SmartProxy extends plugins.EventEmitter {
         this.socketHandlerServer = null;
       }
 
+      // Update datagram handler relay if datagram handler routes changed
+      const hasDatagramHandlers = newRoutes.some(
+        (r) => r.action.type === 'socket-handler' && r.action.datagramHandler
+      );
+
+      if (hasDatagramHandlers && !this.datagramHandlerServer) {
+        const dgPath = `/tmp/smartproxy-dgram-relay-${process.pid}.sock`;
+        this.datagramHandlerServer = new DatagramHandlerServer(dgPath, this.preprocessor);
+        await this.datagramHandlerServer.start();
+        await this.bridge.setDatagramHandlerRelay(this.datagramHandlerServer.getSocketPath());
+      } else if (!hasDatagramHandlers && this.datagramHandlerServer) {
+        await this.datagramHandlerServer.stop();
+        this.datagramHandlerServer = null;
+      }
+
       // Update stored routes
       this.settings.routes = newRoutes;
 

ts/proxies/smart-proxy/utils/route-validator.ts

@@ -123,10 +123,10 @@ export class RouteValidator {
         errors.push(`Invalid action type: ${route.action.type}. Must be one of: ${this.VALID_ACTION_TYPES.join(', ')}`);
       }
 
-      // Validate socket-handler
+      // Validate socket-handler (TCP socketHandler or UDP datagramHandler)
       if (route.action.type === 'socket-handler') {
-        if (typeof route.action.socketHandler !== 'function') {
-          errors.push('socket-handler action requires a socketHandler function');
+        if (typeof route.action.socketHandler !== 'function' && typeof route.action.datagramHandler !== 'function') {
+          errors.push('socket-handler action requires a socketHandler or datagramHandler function');
         }
       }
 
@@ -620,10 +620,12 @@ export function validateRouteAction(action: IRouteAction): { valid: boolean; err
   }
 
   if (action.type === 'socket-handler') {
-    if (!action.socketHandler) {
-      errors.push('Socket handler function is required for socket-handler action');
-    } else if (typeof action.socketHandler !== 'function') {
+    if (!action.socketHandler && !action.datagramHandler) {
+      errors.push('Socket handler or datagram handler function is required for socket-handler action');
+    } else if (action.socketHandler && typeof action.socketHandler !== 'function') {
       errors.push('Socket handler must be a function');
+    } else if (action.datagramHandler && typeof action.datagramHandler !== 'function') {
+      errors.push('Datagram handler must be a function');
     }
   }
 
@@ -714,7 +716,8 @@ export function hasRequiredPropertiesForAction(route: IRouteConfig, actionType:
              route.action.targets.length > 0 &&
              route.action.targets.every(t => t.host && t.port !== undefined);
     case 'socket-handler':
-      return !!route.action.socketHandler && typeof route.action.socketHandler === 'function';
+      return (!!route.action.socketHandler && typeof route.action.socketHandler === 'function') ||
+             (!!route.action.datagramHandler && typeof route.action.datagramHandler === 'function');
     default:
       return false;
   }