add

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

.envrc

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Automatically load the Nix flake development environment
+use flake
+
+# Add project-specific environment variables
+export PROJECT_ROOT="$(pwd)"
+export GOPATH="$PROJECT_ROOT/.go"
+export GOBIN="$GOPATH/bin"
+export GOCACHE="$PROJECT_ROOT/.gocache"
+
+# Add Go bin to PATH
+PATH_add "$GOBIN"
+
+# Load any additional .env file if present
+dotenv_if_exists 

.gitignore

@@ -1 +1,49 @@
-wireguard-go
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+
+# Development environment artifacts
+.go/
+.gocache/
+.direnv/
+result
+result-*
+
+# Editor directories and files
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS generated files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Air live reload
+.air.toml
+tmp/
+
+# Local environment variables
+.env
+.env.local

.golangci.yml

@@ -0,0 +1,174 @@
+run:
+  timeout: 5m
+  issues-exit-code: 1
+  tests: true
+  build-tags:
+    - integration
+
+output:
+  format: colored-line-number
+  print-issued-lines: true
+  print-linter-name: true
+
+linters-settings:
+  errcheck:
+    check-type-assertions: true
+    check-blank: true
+
+  gocyclo:
+    min-complexity: 15
+
+  gofmt:
+    simplify: true
+
+  goimports:
+    local-prefixes: golang.zx2c4.com/wireguard
+
+  golint:
+    min-confidence: 0.8
+
+  govet:
+    check-shadowing: true
+    enable-all: true
+
+  ineffassign:
+    check-exported: false
+
+  misspell:
+    locale: US
+
+  nakedret:
+    max-func-lines: 30
+
+  prealloc:
+    simple: true
+    range-loops: true
+    for-loops: false
+
+  unparam:
+    check-exported: false
+
+  unused:
+    check-exported: false
+
+  whitespace:
+    multi-if: false
+    multi-func: false
+
+  wsl:
+    strict-append: true
+    allow-assign-and-call: true
+    allow-multiline-assign: true
+    allow-cuddle-declarations: false
+    allow-trailing-comment: false
+    force-case-trailing-whitespace: 0
+
+linters:
+  enable:
+    # Default linters
+    - errcheck
+    - gosimple
+    - govet
+    - ineffassign
+    - staticcheck
+    - typecheck
+    - unused
+    
+    # Additional recommended linters
+    - asciicheck
+    - bodyclose
+    - cyclop
+    - dupl
+    - durationcheck
+    - errorlint
+    - exhaustive
+    - exportloopref
+    - forbidigo
+    - forcetypeassert
+    - gochecknoinits
+    - gocognit
+    - goconst
+    - gocritic
+    - gocyclo
+    - godot
+    - gofmt
+    - gofumpt
+    - goheader
+    - goimports
+    - gomnd
+    - gomoddirectives
+    - gomodguard
+    - goprintffuncname
+    - gosec
+    - grouper
+    - importas
+    - maintidx
+    - makezero
+    - misspell
+    - nakedret
+    - nestif
+    - nilerr
+    - nilnil
+    - noctx
+    - nolintlint
+    - prealloc
+    - predeclared
+    - promlinter
+    - revive
+    - rowserrcheck
+    - sqlclosecheck
+    - stylecheck
+    - tenv
+    - testpackage
+    - tparallel
+    - unconvert
+    - unparam
+    - wastedassign
+    - whitespace
+
+  disable:
+    - gochecknoglobals  # Too restrictive for this codebase
+    - goerr113          # Error wrapping style is project-specific
+    - godox             # TODO comments are fine
+    - lll               # Line length is handled by formatter
+    - paralleltest      # Not all tests need to be parallel
+    - wrapcheck         # Error wrapping style is project-specific
+    - varnamelen        # Variable naming style is project-specific
+
+issues:
+  exclude-rules:
+    # Exclude some linters from running on tests files
+    - path: _test\.go
+      linters:
+        - gocyclo
+        - errcheck
+        - dupl
+        - gosec
+        - funlen
+        - goconst
+        - gocognit
+        - scopelint
+        - lll
+
+    # Exclude known false positives
+    - text: "weak cryptographic primitive"
+      linters:
+        - gosec
+      
+    # Ignore certain GoDoc issues
+    - text: "should have a package comment"
+      linters:
+        - golint
+        - stylecheck
+
+  # Maximum issues count per one linter. Set to 0 to disable
+  max-issues-per-linter: 0
+  
+  # Maximum count of issues with the same text. Set to 0 to disable
+  max-same-issues: 0
+
+  # Show only new issues created after git revision `REV`
+  new: false
+
+  # Fix issues automatically when possible
+  fix: false 

MULTIPATH.md

@@ -0,0 +1,268 @@
+# Multi-Path WireGuard Implementation
+
+This document describes the multi-path networking feature for WireGuard-Go, which allows sending the same packet through multiple network interfaces simultaneously.
+
+## Overview
+
+The multi-path implementation extends WireGuard-Go to support redundant packet transmission through multiple network paths. When configured, each outbound packet is sent through ALL specified network interfaces, providing:
+
+- **Increased Reliability**: If one network path fails, communication continues through other paths
+- **Better Performance**: Multiple paths can provide better throughput and lower latency
+- **Redundancy**: Critical for scenarios where network reliability is paramount
+
+## How It Works
+
+### Architecture
+
+The multi-path functionality is implemented through several key components:
+
+1. **MultiPathBind** (`conn/multipath_bind.go`): 
+   - Implements the `conn.Bind` interface
+   - Manages multiple underlying `Bind` instances
+   - Sends packets through ALL configured network paths
+   - Receives packets through the primary path only
+
+2. **Multi-Path Device Creation** (`device/multipath.go`):
+   - Helper functions to create WireGuard devices with multiple network interfaces
+   - Interface discovery and configuration utilities
+
+3. **Network Transmission Flow**:
+   ```
+   TUN Device → Peer Lookup → Packet Staging → Sequential Sender → 
+   SendBuffers → MultiPathBind.Send() → [Bind1, Bind2, Bind3, ...] → Network
+   ```
+
+### Code Locations
+
+The actual network transmission happens in these key locations:
+
+- **Primary Send Method**: `device/peer.go:135` - `peer.device.net.bind.Send(buffers, endpoint)`
+- **Multi-Path Send**: `conn/multipath_bind.go:95` - Sends through all configured binds
+- **Socket Transmission**: `conn/bind_std.go:339` - Individual socket transmission
+
+## Usage
+
+### Basic Usage
+
+```go
+package main
+
+import (
+    "golang.zx2c4.com/wireguard/device"
+    "golang.zx2c4.com/wireguard/tun"
+)
+
+func main() {
+    // Create TUN device
+    tunDevice, err := tun.CreateTUN("wg-multipath", 1420)
+    if err != nil {
+        panic(err)
+    }
+    defer tunDevice.Close()
+
+    // Create logger
+    logger := device.NewLogger(device.LogLevelVerbose, "multipath: ")
+
+    // Create multi-path device using interface names
+    interfaceNames := []string{"eth0", "wlan0"}
+    wgDevice, err := device.NewMultiPathDeviceByNames(tunDevice, interfaceNames, logger)
+    if err != nil {
+        panic(err)
+    }
+    defer wgDevice.Close()
+
+    // Device is ready - configure with wg(8) tools and bring up
+    err = wgDevice.Up()
+    if err != nil {
+        panic(err)
+    }
+
+    // Now all outbound packets will be sent through both eth0 and wlan0
+}
+```
+
+### Advanced Configuration
+
+```go
+// Using interface indexes instead of names
+config := device.MultiPathConfig{
+    InterfaceIndexes: []uint32{2, 3, 4}, // eth0, wlan0, usb0
+    BindFactory: func() conn.Bind {
+        return conn.NewStdNetBind() // or custom bind implementation
+    },
+}
+
+wgDevice, err := device.NewMultiPathDevice(tunDevice, config, logger)
+```
+
+### Command Line Example
+
+Build and run the example program:
+
+```bash
+# Build the example
+go build -o multipath-example ./examples/multipath/
+
+# List available interfaces
+sudo ./multipath-example
+
+# Create multi-path tunnel using eth0 and wlan0
+sudo ./multipath-example eth0 wlan0
+```
+
+## Configuration
+
+### Interface Discovery
+
+Use the helper function to discover available network interfaces:
+
+```go
+interfaces, err := device.GetNetworkInterfaceInfo()
+if err != nil {
+    log.Fatal(err)
+}
+
+for _, iface := range interfaces {
+    fmt.Printf("Interface: %s (index %d)\n", iface.Name, iface.Index)
+    fmt.Printf("  Addresses: %v\n", iface.Addresses)
+    fmt.Printf("  MTU: %d\n", iface.MTU)
+}
+```
+
+### WireGuard Configuration
+
+After creating the multi-path device, configure it normally with `wg(8)`:
+
+```bash
+# Generate keys
+wg genkey | tee private.key | wg pubkey > public.key
+
+# Configure the device
+sudo wg set wg-multipath private-key private.key
+sudo wg set wg-multipath peer <PEER_PUBLIC_KEY> \
+    endpoint <PEER_IP>:<PORT> \
+    allowed-ips 0.0.0.0/0
+
+# Assign IP and bring up
+sudo ip addr add 10.0.0.2/24 dev wg-multipath
+sudo ip link set wg-multipath up
+
+# Route traffic through the tunnel
+sudo ip route add default dev wg-multipath
+```
+
+## Technical Details
+
+### Packet Duplication
+
+When `MultiPathBind.Send()` is called:
+
+1. The same packet buffers are sent through ALL configured network binds
+2. Each bind may be bound to a different network interface
+3. The method succeeds if at least one bind successfully sends the packet
+4. Errors from individual binds are logged but don't stop other binds
+
+### Receiving
+
+- Only the primary bind (first in the list) is used for receiving packets
+- This prevents duplicate packet reception
+- All receive functions come from the primary bind
+
+### Error Handling
+
+- Individual bind failures don't stop transmission through other binds
+- At least one successful transmission is required for overall success
+- Failed binds are logged for debugging
+
+### Performance Considerations
+
+- **CPU Usage**: Sending through multiple interfaces increases CPU usage proportionally
+- **Memory**: Each bind maintains its own buffers and state
+- **Network Bandwidth**: Total bandwidth usage is multiplied by the number of interfaces
+- **Latency**: Latency is determined by the fastest responding interface
+
+## Limitations
+
+1. **Packet Duplication**: Receiving peer will see duplicate packets (WireGuard's replay protection handles this)
+2. **Bandwidth Usage**: Network usage increases proportionally with number of interfaces
+3. **Interface Binding**: Requires platform support for binding sockets to specific interfaces
+4. **Receive Path**: Only receives through primary interface (no multi-path receiving)
+
+## Platform Support
+
+The multi-path functionality works on platforms that support:
+- Socket binding to specific network interfaces
+- Multiple UDP sockets on the same port (with SO_REUSEPORT or similar)
+
+Tested on:
+- Linux (fully supported)
+- macOS (limited support)
+- Windows (limited support)
+
+## Example Scenarios
+
+### Dual-WAN Setup
+Use both your main internet connection and backup cellular connection:
+```go
+interfaces := []string{"eth0", "wwan0"}  // Ethernet + Cellular
+```
+
+### WiFi + Ethernet Redundancy
+For laptops with both WiFi and Ethernet:
+```go
+interfaces := []string{"eth0", "wlan0"}  // Ethernet + WiFi
+```
+
+### Multi-Homed Server
+Server with multiple network interfaces:
+```go
+interfaces := []string{"eth0", "eth1", "eth2"}  // Multiple Ethernet
+```
+
+## Troubleshooting
+
+### Interface Binding Issues
+```bash
+# Check interface exists and is up
+ip link show eth0
+
+# Check interface has IP address
+ip addr show eth0
+
+# Test basic connectivity
+ping -I eth0 8.8.8.8
+```
+
+### Permission Issues
+Multi-path binding typically requires root privileges:
+```bash
+sudo ./your-wireguard-program
+```
+
+### Debugging
+Enable verbose logging to see multi-path operations:
+```go
+logger := device.NewLogger(device.LogLevelVerbose, "multipath: ")
+```
+
+## Building
+
+Ensure you have the modified WireGuard-Go source and build normally:
+
+```bash
+go mod tidy
+go build ./...
+
+# Build example
+go build -o multipath-example ./examples/multipath/
+```
+
+## Future Enhancements
+
+Potential improvements for the multi-path implementation:
+
+1. **Load Balancing**: Distribute packets across interfaces rather than duplicating
+2. **Health Monitoring**: Automatic detection and handling of failed interfaces
+3. **Quality Metrics**: Choose best interface based on latency/bandwidth measurements
+4. **Receive Multi-Path**: Receive from multiple interfaces and handle reordering
+5. **Configuration API**: Runtime configuration of interface sets 

conn/controlfns_linux.go

@@ -13,6 +13,35 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+// Taken from go/src/internal/syscall/unix/kernel_version_linux.go
+func kernelVersion() (major, minor int) {
+	var uname unix.Utsname
+	if err := unix.Uname(&uname); err != nil {
+		return
+	}
+
+	var (
+		values    [2]int
+		value, vi int
+	)
+	for _, c := range uname.Release {
+		if '0' <= c && c <= '9' {
+			value = (value * 10) + int(c-'0')
+		} else {
+			// Note that we're assuming N.N.N here.
+			// If we see anything else, we are likely to mis-parse it.
+			values[vi] = value
+			vi++
+			if vi >= len(values) {
+				break
+			}
+			value = 0
+		}
+	}
+
+	return values[0], values[1]
+}
+
 func init() {
 	controlFns = append(controlFns,
 
@@ -60,6 +89,17 @@ func init() {
 
 		// Attempt to enable UDP_GRO
 		func(network, address string, c syscall.RawConn) error {
+			// Kernels below 5.12 are missing 98184612aca0 ("net:
+			// udp: Add support for getsockopt(..., ..., UDP_GRO,
+			// ..., ...);"), which means we can't read this back
+			// later. We could pipe the return value through to
+			// the rest of the code, but UDP_GRO is kind of buggy
+			// anyway, so just gate this here.
+			major, minor := kernelVersion()
+			if major < 5 || (major == 5 && minor < 12) {
+				return nil
+			}
+
 			c.Control(func(fd uintptr) {
 				_ = unix.SetsockoptInt(int(fd), unix.IPPROTO_UDP, unix.UDP_GRO, 1)
 			})

conn/multipath_bind.go

@@ -0,0 +1,184 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2025 WireGuard LLC. All Rights Reserved.
+ */
+
+package conn
+
+import (
+	"fmt"
+	"sync"
+)
+
+// MultiPathBind implements Bind interface and sends/receives packets through multiple network paths
+type MultiPathBind struct {
+	mu    sync.RWMutex
+	binds []Bind
+}
+
+// NewMultiPathBind creates a new multi-path bind with multiple underlying binds
+func NewMultiPathBind(binds []Bind) *MultiPathBind {
+	if len(binds) == 0 {
+		panic("MultiPathBind requires at least one bind")
+	}
+	
+	return &MultiPathBind{
+		binds: binds,
+	}
+}
+
+// Open puts all binds into listening state and collects receive functions from all binds
+func (mpb *MultiPathBind) Open(port uint16) (fns []ReceiveFunc, actualPort uint16, err error) {
+	mpb.mu.Lock()
+	defer mpb.mu.Unlock()
+
+	// Open first bind to get the actual port
+	var firstBindFns []ReceiveFunc
+	firstBindFns, actualPort, err = mpb.binds[0].Open(port)
+	if err != nil {
+		return nil, 0, fmt.Errorf("failed to open bind 0: %w", err)
+	}
+	
+	// Collect receive functions from the first bind
+	fns = append(fns, firstBindFns...)
+
+	// Open additional binds on the same port and collect their receive functions
+	for i, bind := range mpb.binds[1:] {
+		var bindFns []ReceiveFunc
+		var bindPort uint16
+		bindFns, bindPort, err = bind.Open(actualPort)
+		if err != nil {
+			// If any bind fails, close already opened binds
+			mpb.binds[0].Close()
+			for j := 0; j < i; j++ {
+				mpb.binds[j+1].Close()
+			}
+			return nil, 0, fmt.Errorf("failed to open bind %d: %w", i+1, err)
+		}
+		
+		// Verify all binds use the same port
+		if bindPort != actualPort {
+			mpb.binds[0].Close()
+			for j := 0; j <= i; j++ {
+				mpb.binds[j+1].Close()
+			}
+			return nil, 0, fmt.Errorf("bind %d opened on different port %d vs %d", i+1, bindPort, actualPort)
+		}
+		
+		// Collect receive functions from this bind
+		fns = append(fns, bindFns...)
+	}
+
+	return fns, actualPort, nil
+}
+
+// Close closes all underlying binds
+func (mpb *MultiPathBind) Close() error {
+	mpb.mu.Lock()
+	defer mpb.mu.Unlock()
+
+	var firstErr error
+	for i, bind := range mpb.binds {
+		if err := bind.Close(); err != nil && firstErr == nil {
+			firstErr = fmt.Errorf("failed to close bind %d: %w", i, err)
+		}
+	}
+	return firstErr
+}
+
+// SetMark sets the mark for all underlying binds
+func (mpb *MultiPathBind) SetMark(mark uint32) error {
+	mpb.mu.RLock()
+	defer mpb.mu.RUnlock()
+
+	for i, bind := range mpb.binds {
+		if err := bind.SetMark(mark); err != nil {
+			return fmt.Errorf("failed to set mark on bind %d: %w", i, err)
+		}
+	}
+	return nil
+}
+
+// Send sends the same packets through ALL configured network paths
+func (mpb *MultiPathBind) Send(bufs [][]byte, ep Endpoint) error {
+	mpb.mu.RLock()
+	defer mpb.mu.RUnlock()
+
+	var firstErr error
+	successCount := 0
+
+	// Send through all binds
+	for i, bind := range mpb.binds {
+		if err := bind.Send(bufs, ep); err != nil {
+			if firstErr == nil {
+				firstErr = fmt.Errorf("bind %d failed: %w", i, err)
+			}
+		} else {
+			successCount++
+		}
+	}
+
+	// Consider it successful if at least one path succeeded
+	if successCount > 0 {
+		return nil
+	}
+	
+	return firstErr
+}
+
+// ParseEndpoint uses the first bind to parse endpoints
+func (mpb *MultiPathBind) ParseEndpoint(s string) (Endpoint, error) {
+	mpb.mu.RLock()
+	defer mpb.mu.RUnlock()
+	return mpb.binds[0].ParseEndpoint(s)
+}
+
+// BatchSize returns the minimum batch size among all binds
+func (mpb *MultiPathBind) BatchSize() int {
+	mpb.mu.RLock()
+	defer mpb.mu.RUnlock()
+
+	if len(mpb.binds) == 0 {
+		return 1
+	}
+
+	minBatchSize := mpb.binds[0].BatchSize()
+	for _, bind := range mpb.binds[1:] {
+		if size := bind.BatchSize(); size < minBatchSize {
+			minBatchSize = size
+		}
+	}
+	return minBatchSize
+}
+
+// BindToInterface binds specific binds to specific interfaces
+// This is a helper method for configuring each bind to use different interfaces
+func (mpb *MultiPathBind) BindToInterface(bindIndex int, interfaceIndex uint32, blackhole bool) error {
+	mpb.mu.RLock()
+	defer mpb.mu.RUnlock()
+
+	if bindIndex >= len(mpb.binds) {
+		return fmt.Errorf("bind index %d out of range (have %d binds)", bindIndex, len(mpb.binds))
+	}
+
+	bind := mpb.binds[bindIndex]
+	if binder, ok := bind.(BindSocketToInterface); ok {
+		// Try IPv4 first
+		if err := binder.BindSocketToInterface4(interfaceIndex, blackhole); err != nil {
+			// If IPv4 fails, try IPv6
+			if err := binder.BindSocketToInterface6(interfaceIndex, blackhole); err != nil {
+				return fmt.Errorf("failed to bind to interface %d: %w", interfaceIndex, err)
+			}
+		}
+		return nil
+	}
+	
+	return fmt.Errorf("bind %d does not support interface binding", bindIndex)
+}
+
+// GetBindCount returns the number of configured network paths
+func (mpb *MultiPathBind) GetBindCount() int {
+	mpb.mu.RLock()
+	defer mpb.mu.RUnlock()
+	return len(mpb.binds)
+} 

dev-setup.md

@@ -0,0 +1,247 @@
+# WireGuard Go Development Environment
+
+This repository includes a comprehensive Nix flake development environment with all the tools needed for efficient Go development.
+
+## 🚀 Quick Start
+
+### Prerequisites
+- [Nix](https://nixos.org/download.html) with flakes enabled
+- [direnv](https://direnv.net/) (optional but recommended)
+
+### Setup
+
+1. **Clone and enter the repository:**
+   ```bash
+   git clone <repo-url>
+   cd wireguard-go
+   ```
+
+2. **Option A: Using direnv (Recommended)**
+   ```bash
+   direnv allow
+   ```
+   This will automatically load the development environment when you enter the directory.
+
+3. **Option B: Manual activation**
+   ```bash
+   nix develop
+   ```
+
+## 🔧 Included Tools
+
+### Core Go Tools
+- **Go 1.23.1** - Matching the project's go.mod
+- **gopls** - Official Go Language Server for LSP support
+
+### Code Quality
+- **golangci-lint** - Comprehensive linter with 30+ linters enabled
+- **staticcheck** - Advanced static analysis
+- **gosec** - Security vulnerability scanner
+- **govulncheck** - Official Go vulnerability scanner
+- **gofumpt** - Stricter version of gofmt
+
+### Development Tools
+- **delve** - Go debugger
+- **air** - Live reload for development
+- **gotests** - Automatic test generation
+- **gomodifytags** - Struct tag manipulation
+- **impl** - Interface implementation generator
+- **gotestsum** - Enhanced test output
+
+### System Tools
+- **wireguard-tools** - WireGuard utilities
+- **iproute2** - Network configuration tools
+- **iptables** - Firewall utilities
+
+## 🎯 Quick Commands
+
+### Development Workflow
+```bash
+# Install/update dependencies
+go mod tidy
+
+# Run comprehensive linting
+golangci-lint run
+
+# Check for security vulnerabilities
+govulncheck ./...
+
+# Run tests with coverage
+go test -race -coverprofile=coverage.out ./...
+
+# Generate tests for a package
+gotests -all -w ./device
+
+# Start live reload development server
+air
+
+# Format code with stricter rules
+gofumpt -w .
+```
+
+### Building and Testing
+```bash
+# Build the project
+go build .
+
+# Run all tests
+go test ./...
+
+# Run tests with race detection
+go test -race ./...
+
+# Benchmark tests
+go test -bench=. ./...
+
+# Generate coverage report
+go test -coverprofile=coverage.out ./... && go tool cover -html=coverage.out
+```
+
+### Debugging
+```bash
+# Start delve debugger
+dlv debug
+
+# Debug a specific test
+dlv test ./device
+```
+
+## 📝 Editor Integration
+
+### VS Code
+A `.vscode/settings.json` is included with optimized settings for Go development:
+- Automatic formatting with gofumpt
+- Integrated linting with golangci-lint
+- Proper LSP configuration
+- Optimized file watching and exclusions
+
+### Other Editors
+For vim/neovim, emacs, or other editors that support LSP:
+- Use `gopls` as the language server
+- Point formatters to use `gofumpt` instead of `gofmt`
+- Configure linting to use `golangci-lint`
+
+## 🔍 Code Quality Configuration
+
+### Linting
+The included `.golangci.yml` enables 30+ linters with sensible defaults:
+- Security checks (gosec, G-prefixed rules)
+- Performance optimizations (prealloc, ineffassign)
+- Style consistency (gofumpt, goimports)
+- Bug prevention (errcheck, staticcheck)
+
+### Pre-commit Hooks (Optional)
+Consider setting up pre-commit hooks:
+```bash
+# Create .git/hooks/pre-commit
+#!/bin/bash
+set -e
+golangci-lint run
+go test ./...
+govulncheck ./...
+```
+
+## 🌍 Environment Variables
+
+The flake automatically sets up:
+- `GOPATH="$PWD/.go"`
+- `GOBIN="$PWD/.go/bin"`
+- `GOCACHE="$PWD/.gocache"`
+- `GO111MODULE=on`
+- `CGO_ENABLED=1`
+- `WG_COLOR_MODE=always`
+
+## 🧪 Testing
+
+### Running Tests
+```bash
+# All tests
+go test ./...
+
+# With race detection
+go test -race ./...
+
+# Verbose output
+go test -v ./...
+
+# Specific package
+go test ./device
+
+# With coverage
+go test -coverprofile=coverage.out ./...
+```
+
+### Test Generation
+```bash
+# Generate tests for all functions in a package
+gotests -all -w ./device
+
+# Generate tests for specific functions
+gotests -only FunctionName -w ./device
+```
+
+## 🔒 Security
+
+### Vulnerability Scanning
+```bash
+# Scan for known vulnerabilities
+govulncheck ./...
+
+# Security-focused linting
+gosec ./...
+```
+
+### WireGuard-Specific Security
+The environment includes networking tools for testing:
+- WireGuard tools for protocol testing
+- Network namespace utilities
+- Traffic analysis tools
+
+## 📦 Building Packages
+
+### Development Build
+```bash
+go build .
+```
+
+### Optimized Build
+```bash
+go build -ldflags="-w -s" .
+```
+
+### Using Nix to Build
+```bash
+# Build using the included Nix package
+nix build
+
+# The binary will be in ./result/bin/
+```
+
+## 🐛 Troubleshooting
+
+### Common Issues
+
+1. **"command not found" errors**
+   - Ensure you're in the flake environment: `nix develop`
+   - Or allow direnv: `direnv allow`
+
+2. **Go module issues**
+   - Clean module cache: `go clean -modcache`
+   - Verify modules: `go mod verify`
+
+3. **LSP not working**
+   - Restart your editor
+   - Check gopls is available: `which gopls`
+   - Verify Go version: `go version`
+
+### Performance Tips
+- Use `.gocache` for faster builds (already configured)
+- Exclude build artifacts from file watchers
+- Use `gotestsum` for faster test feedback
+
+## 📚 Additional Resources
+
+- [Go Documentation](https://golang.org/doc/)
+- [WireGuard Protocol](https://www.wireguard.com/protocol/)
+- [golangci-lint Documentation](https://golangci-lint.run/)
+- [Delve Debugger](https://github.com/go-delve/delve) 

device/allowedips.go

@@ -223,19 +223,11 @@ func (table *AllowedIPs) EntriesForPeer(peer *Peer, cb func(prefix netip.Prefix)
 	}
 }
 
-func (table *AllowedIPs) RemoveByPeer(peer *Peer) {
+func (node *trieEntry) remove() {
-	table.mutex.Lock()
-	defer table.mutex.Unlock()
-
-	var next *list.Element
-	for elem := peer.trieEntries.Front(); elem != nil; elem = next {
-		next = elem.Next()
-		node := elem.Value.(*trieEntry)
-
 	node.removeFromPeerEntries()
 	node.peer = nil
 	if node.child[0] != nil && node.child[1] != nil {
-			continue
+		return
 	}
 	bit := 0
 	if node.child[0] == nil {
@@ -248,12 +240,12 @@ func (table *AllowedIPs) RemoveByPeer(peer *Peer) {
 	*node.parent.parentBit = child
 	if node.child[0] != nil || node.child[1] != nil || node.parent.parentBitType > 1 {
 		node.zeroizePointers()
-			continue
+		return
 	}
 	parent := (*trieEntry)(unsafe.Pointer(uintptr(unsafe.Pointer(node.parent.parentBit)) - unsafe.Offsetof(node.child) - unsafe.Sizeof(node.child[0])*uintptr(node.parent.parentBitType)))
 	if parent.peer != nil {
 		node.zeroizePointers()
-			continue
+		return
 	}
 	child = parent.child[node.parent.parentBitType^1]
 	if child != nil {
@@ -263,6 +255,37 @@ func (table *AllowedIPs) RemoveByPeer(peer *Peer) {
 	node.zeroizePointers()
 	parent.zeroizePointers()
 }
+
+func (table *AllowedIPs) Remove(prefix netip.Prefix, peer *Peer) {
+	table.mutex.Lock()
+	defer table.mutex.Unlock()
+	var node *trieEntry
+	var exact bool
+
+	if prefix.Addr().Is6() {
+		ip := prefix.Addr().As16()
+		node, exact = table.IPv6.nodePlacement(ip[:], uint8(prefix.Bits()))
+	} else if prefix.Addr().Is4() {
+		ip := prefix.Addr().As4()
+		node, exact = table.IPv4.nodePlacement(ip[:], uint8(prefix.Bits()))
+	} else {
+		panic(errors.New("removing unknown address type"))
+	}
+	if !exact || node == nil || peer != node.peer {
+		return
+	}
+	node.remove()
+}
+
+func (table *AllowedIPs) RemoveByPeer(peer *Peer) {
+	table.mutex.Lock()
+	defer table.mutex.Unlock()
+
+	var next *list.Element
+	for elem := peer.trieEntries.Front(); elem != nil; elem = next {
+		next = elem.Next()
+		elem.Value.(*trieEntry).remove()
+	}
 }
 
 func (table *AllowedIPs) Insert(prefix netip.Prefix, peer *Peer) {

device/allowedips_test.go

@@ -101,6 +101,10 @@ func TestTrieIPv4(t *testing.T) {
 		allowedIPs.Insert(netip.PrefixFrom(netip.AddrFrom4([4]byte{a, b, c, d}), int(cidr)), peer)
 	}
 
+	remove := func(peer *Peer, a, b, c, d byte, cidr uint8) {
+		allowedIPs.Remove(netip.PrefixFrom(netip.AddrFrom4([4]byte{a, b, c, d}), int(cidr)), peer)
+	}
+
 	assertEQ := func(peer *Peer, a, b, c, d byte) {
 		p := allowedIPs.Lookup([]byte{a, b, c, d})
 		if p != peer {
@@ -176,6 +180,21 @@ func TestTrieIPv4(t *testing.T) {
 	allowedIPs.RemoveByPeer(a)
 
 	assertNEQ(a, 192, 168, 0, 1)
+
+	insert(a, 1, 0, 0, 0, 32)
+	insert(a, 192, 0, 0, 0, 24)
+	assertEQ(a, 1, 0, 0, 0)
+	assertEQ(a, 192, 0, 0, 1)
+	remove(a, 192, 0, 0, 0, 32)
+	assertEQ(a, 192, 0, 0, 1)
+	remove(nil, 192, 0, 0, 0, 24)
+	assertEQ(a, 192, 0, 0, 1)
+	remove(b, 192, 0, 0, 0, 24)
+	assertEQ(a, 192, 0, 0, 1)
+	remove(a, 192, 0, 0, 0, 24)
+	assertNEQ(a, 192, 0, 0, 1)
+	remove(a, 1, 0, 0, 0, 32)
+	assertNEQ(a, 1, 0, 0, 0)
 }
 
 /* Test ported from kernel implementation:
@@ -211,6 +230,15 @@ func TestTrieIPv6(t *testing.T) {
 		allowedIPs.Insert(netip.PrefixFrom(netip.AddrFrom16(*(*[16]byte)(addr)), int(cidr)), peer)
 	}
 
+	remove := func(peer *Peer, a, b, c, d uint32, cidr uint8) {
+		var addr []byte
+		addr = append(addr, expand(a)...)
+		addr = append(addr, expand(b)...)
+		addr = append(addr, expand(c)...)
+		addr = append(addr, expand(d)...)
+		allowedIPs.Remove(netip.PrefixFrom(netip.AddrFrom16(*(*[16]byte)(addr)), int(cidr)), peer)
+	}
+
 	assertEQ := func(peer *Peer, a, b, c, d uint32) {
 		var addr []byte
 		addr = append(addr, expand(a)...)
@@ -223,6 +251,18 @@ func TestTrieIPv6(t *testing.T) {
 		}
 	}
 
+	assertNEQ := func(peer *Peer, a, b, c, d uint32) {
+		var addr []byte
+		addr = append(addr, expand(a)...)
+		addr = append(addr, expand(b)...)
+		addr = append(addr, expand(c)...)
+		addr = append(addr, expand(d)...)
+		p := allowedIPs.Lookup(addr)
+		if p == peer {
+			t.Error("Assert NEQ failed")
+		}
+	}
+
 	insert(d, 0x26075300, 0x60006b00, 0, 0xc05f0543, 128)
 	insert(c, 0x26075300, 0x60006b00, 0, 0, 64)
 	insert(e, 0, 0, 0, 0, 0)
@@ -244,4 +284,21 @@ func TestTrieIPv6(t *testing.T) {
 	assertEQ(h, 0x24046800, 0x40040800, 0, 0)
 	assertEQ(h, 0x24046800, 0x40040800, 0x10101010, 0x10101010)
 	assertEQ(a, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef)
+
+	insert(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef, 128)
+	insert(a, 0x24446800, 0xf0e40800, 0xeeaebeef, 0, 98)
+	assertEQ(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef)
+	assertEQ(a, 0x24446800, 0xf0e40800, 0xeeaebeef, 0x10101010)
+	remove(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef, 96)
+	assertEQ(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef)
+	remove(nil, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef, 128)
+	assertEQ(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef)
+	remove(b, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef, 128)
+	assertEQ(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef)
+	remove(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef, 128)
+	assertNEQ(a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef)
+	remove(b, 0x24446800, 0xf0e40800, 0xeeaebeef, 0, 98)
+	assertEQ(a, 0x24446800, 0xf0e40800, 0xeeaebeef, 0x10101010)
+	remove(a, 0x24446800, 0xf0e40800, 0xeeaebeef, 0, 98)
+	assertNEQ(a, 0x24446800, 0xf0e40800, 0xeeaebeef, 0x10101010)
 }

device/multipath.go

@@ -0,0 +1,169 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2025 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"fmt"
+	"net"
+
+	"golang.zx2c4.com/wireguard/conn"
+	"golang.zx2c4.com/wireguard/tun"
+)
+
+// MultiPathConfig represents configuration for multi-path networking
+type MultiPathConfig struct {
+	// InterfaceIndexes are the network interface indexes to bind to
+	// If empty, uses default interface selection
+	InterfaceIndexes []uint32
+	// BindFactory creates new Bind instances. If nil, uses conn.NewStdNetBind()
+	BindFactory func() conn.Bind
+}
+
+// NewMultiPathDevice creates a new WireGuard device with multi-path networking
+// It creates separate bind instances for each specified network interface
+func NewMultiPathDevice(tunDevice tun.Device, config MultiPathConfig, logger *Logger) (*Device, error) {
+	if len(config.InterfaceIndexes) == 0 {
+		return nil, fmt.Errorf("MultiPathConfig must specify at least one interface index")
+	}
+
+	// Use default bind factory if none specified
+	bindFactory := config.BindFactory
+	if bindFactory == nil {
+		bindFactory = func() conn.Bind {
+			return conn.NewStdNetBind()
+		}
+	}
+
+	// Create a bind for each interface
+	binds := make([]conn.Bind, len(config.InterfaceIndexes))
+	for i := range config.InterfaceIndexes {
+		binds[i] = bindFactory()
+	}
+
+	// Create multi-path bind
+	multiPathBind := conn.NewMultiPathBind(binds)
+
+	// Configure each bind to use its specific interface
+	for i, interfaceIndex := range config.InterfaceIndexes {
+		err := multiPathBind.BindToInterface(i, interfaceIndex, false)
+		if err != nil {
+			logger.Errorf("Failed to bind to interface %d: %v", interfaceIndex, err)
+			// Continue with other interfaces rather than failing completely
+		} else {
+			logger.Verbosef("Bound network path %d to interface index %d", i, interfaceIndex)
+		}
+	}
+
+	// Create device with multi-path bind
+	device := NewDevice(tunDevice, multiPathBind, logger)
+	
+	logger.Verbosef("Created multi-path WireGuard device with %d network paths", len(config.InterfaceIndexes))
+	return device, nil
+}
+
+// NewMultiPathDeviceByNames creates a multi-path device using interface names instead of indexes
+func NewMultiPathDeviceByNames(tunDevice tun.Device, interfaceNames []string, logger *Logger) (*Device, error) {
+	if len(interfaceNames) == 0 {
+		return nil, fmt.Errorf("must specify at least one interface name")
+	}
+
+	// Convert interface names to indexes
+	interfaceIndexes := make([]uint32, len(interfaceNames))
+	for i, name := range interfaceNames {
+		iface, err := net.InterfaceByName(name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to find interface %s: %w", name, err)
+		}
+		interfaceIndexes[i] = uint32(iface.Index)
+		logger.Verbosef("Interface %s has index %d", name, iface.Index)
+	}
+
+	config := MultiPathConfig{
+		InterfaceIndexes: interfaceIndexes,
+	}
+
+	return NewMultiPathDevice(tunDevice, config, logger)
+}
+
+// GetNetworkInterfaceInfo returns information about available network interfaces
+func GetNetworkInterfaceInfo() ([]NetworkInterfaceInfo, error) {
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		return nil, fmt.Errorf("failed to list network interfaces: %w", err)
+	}
+
+	result := make([]NetworkInterfaceInfo, 0, len(interfaces))
+	for _, iface := range interfaces {
+		// Skip loopback and down interfaces for multi-path networking
+		if iface.Flags&net.FlagLoopback != 0 || iface.Flags&net.FlagUp == 0 {
+			continue
+		}
+
+		addrs, _ := iface.Addrs()
+		addrStrings := make([]string, len(addrs))
+		for i, addr := range addrs {
+			addrStrings[i] = addr.String()
+		}
+
+		result = append(result, NetworkInterfaceInfo{
+			Index:     uint32(iface.Index),
+			Name:      iface.Name,
+			Addresses: addrStrings,
+			MTU:       iface.MTU,
+			Flags:     iface.Flags,
+		})
+	}
+
+	return result, nil
+}
+
+// NetworkInterfaceInfo represents information about a network interface
+type NetworkInterfaceInfo struct {
+	Index     uint32
+	Name      string
+	Addresses []string
+	MTU       int
+	Flags     net.Flags
+}
+
+// String returns a human-readable description of the interface
+func (nii NetworkInterfaceInfo) String() string {
+	return fmt.Sprintf("Interface %s (index %d): MTU=%d, Addresses=%v, Flags=%v", 
+		nii.Name, nii.Index, nii.MTU, nii.Addresses, nii.Flags)
+}
+
+// Example usage function
+func ExampleMultiPathUsage(logger *Logger) {
+	// Print available interfaces
+	interfaces, err := GetNetworkInterfaceInfo()
+	if err != nil {
+		logger.Errorf("Failed to get interface info: %v", err)
+		return
+	}
+
+	logger.Verbosef("Available network interfaces:")
+	for _, iface := range interfaces {
+		logger.Verbosef("  %s", iface.String())
+	}
+
+	// Example: Create multi-path device using specific interface names
+	// This would send each packet through both eth0 and wlan0
+	
+	// Note: You would need to create/configure your TUN device
+	// tunDevice, err := tun.CreateTUN("wg0", 1420)
+	// if err != nil {
+	//     logger.Errorf("Failed to create TUN: %v", err)
+	//     return
+	// }
+	// 
+	// device, err := NewMultiPathDeviceByNames(tunDevice, interfaceNames, logger)
+	// if err != nil {
+	//     logger.Errorf("Failed to create multi-path device: %v", err)
+	//     return
+	// }
+	// 
+	// logger.Verbosef("Multi-path WireGuard device created successfully")
+} 

device/noise-protocol.go

@@ -6,6 +6,7 @@
 package device
 
 import (
+	"encoding/binary"
 	"errors"
 	"fmt"
 	"sync"
@@ -13,7 +14,6 @@ import (
 
 	"golang.org/x/crypto/blake2s"
 	"golang.org/x/crypto/chacha20poly1305"
-	"golang.org/x/crypto/poly1305"
 
 	"golang.zx2c4.com/wireguard/tai64n"
 )
@@ -64,7 +64,7 @@ const (
 	MessageResponseSize        = 92                                            // size of response message
 	MessageCookieReplySize     = 64                                            // size of cookie reply message
 	MessageTransportHeaderSize = 16                                            // size of data preceding content in transport message
-	MessageTransportSize       = MessageTransportHeaderSize + poly1305.TagSize // size of empty transport
+	MessageTransportSize       = MessageTransportHeaderSize // size of empty transport (no encryption tag)
 	MessageKeepaliveSize       = MessageTransportSize                          // size of keepalive
 	MessageHandshakeSize       = MessageInitiationSize                         // size of largest handshake related message
 )
@@ -85,8 +85,8 @@ type MessageInitiation struct {
 	Type      uint32
 	Sender    uint32
 	Ephemeral NoisePublicKey
-	Static    [NoisePublicKeySize + poly1305.TagSize]byte
+	Static    [NoisePublicKeySize + Poly1305TagSize]byte
-	Timestamp [tai64n.TimestampSize + poly1305.TagSize]byte
+	Timestamp [tai64n.TimestampSize + Poly1305TagSize]byte
 	MAC1      [blake2s.Size128]byte
 	MAC2      [blake2s.Size128]byte
 }
@@ -96,7 +96,7 @@ type MessageResponse struct {
 	Sender    uint32
 	Receiver  uint32
 	Ephemeral NoisePublicKey
-	Empty     [poly1305.TagSize]byte
+	Empty     [Poly1305TagSize]byte
 	MAC1      [blake2s.Size128]byte
 	MAC2      [blake2s.Size128]byte
 }
@@ -112,7 +112,99 @@ type MessageCookieReply struct {
 	Type     uint32
 	Receiver uint32
 	Nonce    [chacha20poly1305.NonceSizeX]byte
-	Cookie   [blake2s.Size128 + poly1305.TagSize]byte
+	Cookie   [blake2s.Size128 + Poly1305TagSize]byte
+}
+
+var errMessageLengthMismatch = errors.New("message length mismatch")
+
+func (msg *MessageInitiation) unmarshal(b []byte) error {
+	if len(b) != MessageInitiationSize {
+		return errMessageLengthMismatch
+	}
+
+	msg.Type = binary.LittleEndian.Uint32(b)
+	msg.Sender = binary.LittleEndian.Uint32(b[4:])
+	copy(msg.Ephemeral[:], b[8:])
+	copy(msg.Static[:], b[8+len(msg.Ephemeral):])
+	copy(msg.Timestamp[:], b[8+len(msg.Ephemeral)+len(msg.Static):])
+	copy(msg.MAC1[:], b[8+len(msg.Ephemeral)+len(msg.Static)+len(msg.Timestamp):])
+	copy(msg.MAC2[:], b[8+len(msg.Ephemeral)+len(msg.Static)+len(msg.Timestamp)+len(msg.MAC1):])
+
+	return nil
+}
+
+func (msg *MessageInitiation) marshal(b []byte) error {
+	if len(b) != MessageInitiationSize {
+		return errMessageLengthMismatch
+	}
+
+	binary.LittleEndian.PutUint32(b, msg.Type)
+	binary.LittleEndian.PutUint32(b[4:], msg.Sender)
+	copy(b[8:], msg.Ephemeral[:])
+	copy(b[8+len(msg.Ephemeral):], msg.Static[:])
+	copy(b[8+len(msg.Ephemeral)+len(msg.Static):], msg.Timestamp[:])
+	copy(b[8+len(msg.Ephemeral)+len(msg.Static)+len(msg.Timestamp):], msg.MAC1[:])
+	copy(b[8+len(msg.Ephemeral)+len(msg.Static)+len(msg.Timestamp)+len(msg.MAC1):], msg.MAC2[:])
+
+	return nil
+}
+
+func (msg *MessageResponse) unmarshal(b []byte) error {
+	if len(b) != MessageResponseSize {
+		return errMessageLengthMismatch
+	}
+
+	msg.Type = binary.LittleEndian.Uint32(b)
+	msg.Sender = binary.LittleEndian.Uint32(b[4:])
+	msg.Receiver = binary.LittleEndian.Uint32(b[8:])
+	copy(msg.Ephemeral[:], b[12:])
+	copy(msg.Empty[:], b[12+len(msg.Ephemeral):])
+	copy(msg.MAC1[:], b[12+len(msg.Ephemeral)+len(msg.Empty):])
+	copy(msg.MAC2[:], b[12+len(msg.Ephemeral)+len(msg.Empty)+len(msg.MAC1):])
+
+	return nil
+}
+
+func (msg *MessageResponse) marshal(b []byte) error {
+	if len(b) != MessageResponseSize {
+		return errMessageLengthMismatch
+	}
+
+	binary.LittleEndian.PutUint32(b, msg.Type)
+	binary.LittleEndian.PutUint32(b[4:], msg.Sender)
+	binary.LittleEndian.PutUint32(b[8:], msg.Receiver)
+	copy(b[12:], msg.Ephemeral[:])
+	copy(b[12+len(msg.Ephemeral):], msg.Empty[:])
+	copy(b[12+len(msg.Ephemeral)+len(msg.Empty):], msg.MAC1[:])
+	copy(b[12+len(msg.Ephemeral)+len(msg.Empty)+len(msg.MAC1):], msg.MAC2[:])
+
+	return nil
+}
+
+func (msg *MessageCookieReply) unmarshal(b []byte) error {
+	if len(b) != MessageCookieReplySize {
+		return errMessageLengthMismatch
+	}
+
+	msg.Type = binary.LittleEndian.Uint32(b)
+	msg.Receiver = binary.LittleEndian.Uint32(b[4:])
+	copy(msg.Nonce[:], b[8:])
+	copy(msg.Cookie[:], b[8+len(msg.Nonce):])
+
+	return nil
+}
+
+func (msg *MessageCookieReply) marshal(b []byte) error {
+	if len(b) != MessageCookieReplySize {
+		return errMessageLengthMismatch
+	}
+
+	binary.LittleEndian.PutUint32(b, msg.Type)
+	binary.LittleEndian.PutUint32(b[4:], msg.Receiver)
+	copy(b[8:], msg.Nonce[:])
+	copy(b[8+len(msg.Nonce):], msg.Cookie[:])
+
+	return nil
 }
 
 type Handshake struct {
@@ -522,27 +614,13 @@ func (peer *Peer) BeginSymmetricSession() error {
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
 
-	// derive keys
+	// determine initiator role
 
 	var isInitiator bool
-	var sendKey [chacha20poly1305.KeySize]byte
-	var recvKey [chacha20poly1305.KeySize]byte
 
 	if handshake.state == handshakeResponseConsumed {
-		KDF2(
-			&sendKey,
-			&recvKey,
-			handshake.chainKey[:],
-			nil,
-		)
 		isInitiator = true
 	} else if handshake.state == handshakeResponseCreated {
-		KDF2(
-			&recvKey,
-			&sendKey,
-			handshake.chainKey[:],
-			nil,
-		)
 		isInitiator = false
 	} else {
 		return fmt.Errorf("invalid state for keypair derivation: %v", handshake.state)
@@ -551,18 +629,15 @@ func (peer *Peer) BeginSymmetricSession() error {
 	// zero handshake
 
 	setZero(handshake.chainKey[:])
-	setZero(handshake.hash[:]) // Doesn't necessarily need to be zeroed. Could be used for something interesting down the line.
+	setZero(handshake.hash[:])
 	setZero(handshake.localEphemeral[:])
 	peer.handshake.state = handshakeZeroed
 
-	// create AEAD instances
+	// create keypair without encryption
 
 	keypair := new(Keypair)
-	keypair.send, _ = chacha20poly1305.New(sendKey[:])
+	keypair.send = nil  // no encryption
-	keypair.receive, _ = chacha20poly1305.New(recvKey[:])
+	keypair.receive = nil  // no decryption
-
-	setZero(sendKey[:])
-	setZero(recvKey[:])
 
 	keypair.created = time.Now()
 	keypair.replayFilter.Reset()

device/noise-types.go

@@ -15,6 +15,7 @@ const (
 	NoisePublicKeySize    = 32
 	NoisePrivateKeySize   = 32
 	NoisePresharedKeySize = 32
+	Poly1305TagSize       = 16 // Size of Poly1305 authentication tag
 )
 
 type (

device/receive.go

@@ -6,14 +6,12 @@
 package device
 
 import (
-	"bytes"
 	"encoding/binary"
 	"errors"
 	"net"
 	"sync"
 	"time"
 
-	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/net/ipv4"
 	"golang.org/x/net/ipv6"
 	"golang.zx2c4.com/wireguard/conn"
@@ -237,8 +235,6 @@ func (device *Device) RoutineReceiveIncoming(maxBatchSize int, recv conn.Receive
 }
 
 func (device *Device) RoutineDecryption(id int) {
-	var nonce [chacha20poly1305.NonceSize]byte
-
 	defer device.log.Verbosef("Routine: decryption worker %d - stopped", id)
 	device.log.Verbosef("Routine: decryption worker %d - started", id)
 
@@ -248,20 +244,9 @@ func (device *Device) RoutineDecryption(id int) {
 			counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent]
 			content := elem.packet[MessageTransportOffsetContent:]
 
-			// decrypt and release to consumer
+			// pass through content without decryption
-			var err error
 			elem.counter = binary.LittleEndian.Uint64(counter)
-			// copy counter to nonce
+			elem.packet = content
-			binary.LittleEndian.PutUint64(nonce[0x4:0xc], elem.counter)
-			elem.packet, err = elem.keypair.receive.Open(
-				content[:0],
-				nonce[:],
-				content,
-				nil,
-			)
-			if err != nil {
-				elem.packet = nil
-			}
 		}
 		elemsContainer.Unlock()
 	}
@@ -287,8 +272,7 @@ func (device *Device) RoutineHandshake(id int) {
 			// unmarshal packet
 
 			var reply MessageCookieReply
-			reader := bytes.NewReader(elem.packet)
+			err := reply.unmarshal(elem.packet)
-			err := binary.Read(reader, binary.LittleEndian, &reply)
 			if err != nil {
 				device.log.Verbosef("Failed to decode cookie reply")
 				goto skip
@@ -353,8 +337,7 @@ func (device *Device) RoutineHandshake(id int) {
 			// unmarshal
 
 			var msg MessageInitiation
-			reader := bytes.NewReader(elem.packet)
+			err := msg.unmarshal(elem.packet)
-			err := binary.Read(reader, binary.LittleEndian, &msg)
 			if err != nil {
 				device.log.Errorf("Failed to decode initiation message")
 				goto skip
@@ -386,8 +369,7 @@ func (device *Device) RoutineHandshake(id int) {
 			// unmarshal
 
 			var msg MessageResponse
-			reader := bytes.NewReader(elem.packet)
+			err := msg.unmarshal(elem.packet)
-			err := binary.Read(reader, binary.LittleEndian, &msg)
 			if err != nil {
 				device.log.Errorf("Failed to decode response message")
 				goto skip

device/send.go

@@ -6,7 +6,6 @@
 package device
 
 import (
-	"bytes"
 	"encoding/binary"
 	"errors"
 	"net"
@@ -14,7 +13,6 @@ import (
 	"sync"
 	"time"
 
-	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/net/ipv4"
 	"golang.org/x/net/ipv6"
 	"golang.zx2c4.com/wireguard/conn"
@@ -124,10 +122,8 @@ func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
 		return err
 	}
 
-	var buf [MessageInitiationSize]byte
+	packet := make([]byte, MessageInitiationSize)
-	writer := bytes.NewBuffer(buf[:0])
+	_ = msg.marshal(packet)
-	binary.Write(writer, binary.LittleEndian, msg)
-	packet := writer.Bytes()
 	peer.cookieGenerator.AddMacs(packet)
 
 	peer.timersAnyAuthenticatedPacketTraversal()
@@ -155,10 +151,8 @@ func (peer *Peer) SendHandshakeResponse() error {
 		return err
 	}
 
-	var buf [MessageResponseSize]byte
+	packet := make([]byte, MessageResponseSize)
-	writer := bytes.NewBuffer(buf[:0])
+	_ = response.marshal(packet)
-	binary.Write(writer, binary.LittleEndian, response)
-	packet := writer.Bytes()
 	peer.cookieGenerator.AddMacs(packet)
 
 	err = peer.BeginSymmetricSession()
@@ -189,11 +183,11 @@ func (device *Device) SendHandshakeCookie(initiatingElem *QueueHandshakeElement)
 		return err
 	}
 
-	var buf [MessageCookieReplySize]byte
+	packet := make([]byte, MessageCookieReplySize)
-	writer := bytes.NewBuffer(buf[:0])
+	_ = reply.marshal(packet)
-	binary.Write(writer, binary.LittleEndian, reply)
 	// TODO: allocation could be avoided
-	device.net.bind.Send([][]byte{writer.Bytes()}, initiatingElem.endpoint)
+	device.net.bind.Send([][]byte{packet}, initiatingElem.endpoint)
+
 	return nil
 }
 
@@ -436,15 +430,12 @@ func calculatePaddingSize(packetSize, mtu int) int {
 	return paddedSize - lastUnit
 }
 
-/* Encrypts the elements in the queue
+/* Processes the elements in the queue without encryption
  * and marks them for sequential consumption (by releasing the mutex)
  *
  * Obs. One instance per core
  */
 func (device *Device) RoutineEncryption(id int) {
-	var paddingZeros [PaddingMultiple]byte
-	var nonce [chacha20poly1305.NonceSize]byte
-
 	defer device.log.Verbosef("Routine: encryption worker %d - stopped", id)
 	device.log.Verbosef("Routine: encryption worker %d - started", id)
 
@@ -461,19 +452,9 @@ func (device *Device) RoutineEncryption(id int) {
 			binary.LittleEndian.PutUint32(fieldReceiver, elem.keypair.remoteIndex)
 			binary.LittleEndian.PutUint64(fieldNonce, elem.nonce)
 
-			// pad content to multiple of 16
+			// append content directly to header without encryption
-			paddingSize := calculatePaddingSize(len(elem.packet), int(device.tun.mtu.Load()))
+			copy(elem.buffer[MessageTransportHeaderSize:], elem.packet)
-			elem.packet = append(elem.packet, paddingZeros[:paddingSize]...)
+			elem.packet = elem.buffer[:MessageTransportHeaderSize+len(elem.packet)]
-
-			// encrypt content and release to consumer
-
-			binary.LittleEndian.PutUint64(nonce[4:], elem.nonce)
-			elem.packet = elem.keypair.send.Seal(
-				header,
-				nonce[:],
-				elem.packet,
-				nil,
-			)
 		}
 		elemsContainer.Unlock()
 	}

device/uapi.go

@@ -371,7 +371,14 @@ func (device *Device) handlePeerLine(peer *ipcSetPeer, key, value string) error
 		device.allowedips.RemoveByPeer(peer.Peer)
 
 	case "allowed_ip":
-		device.log.Verbosef("%v - UAPI: Adding allowedip", peer.Peer)
+		add := true
+		verb := "Adding"
+		if len(value) > 0 && value[0] == '-' {
+			add = false
+			verb = "Removing"
+			value = value[1:]
+		}
+		device.log.Verbosef("%v - UAPI: %s allowedip", peer.Peer, verb)
 		prefix, err := netip.ParsePrefix(value)
 		if err != nil {
 			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set allowed ip: %w", err)
@@ -379,7 +386,11 @@ func (device *Device) handlePeerLine(peer *ipcSetPeer, key, value string) error
 		if peer.dummy {
 			return nil
 		}
+		if add {
 			device.allowedips.Insert(prefix, peer.Peer)
+		} else {
+			device.allowedips.Remove(prefix, peer.Peer)
+		}
 
 	case "protocol_version":
 		if value != "1" {

examples/multipath/build.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+# Build script for multi-path WireGuard example
+
+set -e
+
+echo "Building multi-path WireGuard example..."
+
+# Ensure we're in the right directory
+cd "$(dirname "$0")"
+
+# Build the example
+go build -o multipath-example main.go
+
+echo "Build complete! Executable: ./multipath-example"
+echo ""
+echo "Usage examples:"
+echo "  # List available interfaces:"
+echo "  sudo ./multipath-example"
+echo ""
+echo "  # Create multi-path tunnel:"
+echo "  sudo ./multipath-example eth0 wlan0"
+echo ""
+echo "Note: This example requires root privileges to create TUN devices and bind to interfaces." 

examples/multipath/main.go

@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Multi-path WireGuard Example
+ *
+ * This example demonstrates how to create a WireGuard device that sends
+ * packets through multiple network interfaces simultaneously.
+ */
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun"
+)
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Printf("Usage: %s <interface1> [interface2] [interface3] ...\n", os.Args[0])
+		fmt.Println("Example: sudo ./multipath eth0 wlan0")
+		fmt.Println("\nThis will create a WireGuard tunnel that sends packets through both eth0 and wlan0")
+		fmt.Println("Available interfaces:")
+		
+		interfaces, err := device.GetNetworkInterfaceInfo()
+		if err != nil {
+			log.Fatalf("Failed to get interface info: %v", err)
+		}
+		
+		for _, iface := range interfaces {
+			fmt.Printf("  %s\n", iface.String())
+		}
+		os.Exit(1)
+	}
+
+	// Get interface names from command line
+	interfaceNames := os.Args[1:]
+	
+	fmt.Printf("Creating multi-path WireGuard device using interfaces: %v\n", interfaceNames)
+
+	// Create logger
+	logger := device.NewLogger(device.LogLevelVerbose, "multipath-example: ")
+
+	// Create TUN device
+	tunDevice, err := tun.CreateTUN("wg-multipath", 1420)
+	if err != nil {
+		log.Fatalf("Failed to create TUN device: %v", err)
+	}
+	defer tunDevice.Close()
+
+	fmt.Printf("Created TUN device: %s\n", tunDevice.Name())
+
+	// Create multi-path WireGuard device
+	wgDevice, err := device.NewMultiPathDeviceByNames(tunDevice, interfaceNames, logger)
+	if err != nil {
+		log.Fatalf("Failed to create multi-path WireGuard device: %v", err)
+	}
+	defer wgDevice.Close()
+
+	fmt.Printf("Multi-path WireGuard device created successfully!\n")
+	fmt.Printf("Each outbound packet will be sent through ALL %d specified interfaces\n", len(interfaceNames))
+
+	// Configure WireGuard (you would normally load this from a config file)
+	// This is just a basic example configuration
+	logger.Verbosef("Device ready. You can now configure it using wg(8) commands:")
+	logger.Verbosef("  sudo wg set %s private-key <private-key-file>", tunDevice.Name())
+	logger.Verbosef("  sudo wg set %s peer <peer-public-key> endpoint <peer-endpoint> allowed-ips <allowed-ips>", tunDevice.Name())
+	logger.Verbosef("  sudo ip addr add <your-vpn-ip>/24 dev %s", tunDevice.Name())
+	logger.Verbosef("  sudo ip link set %s up", tunDevice.Name())
+
+	// Bring device up
+	err = wgDevice.Up()
+	if err != nil {
+		log.Fatalf("Failed to bring device up: %v", err)
+	}
+
+	fmt.Println("WireGuard device is up and running!")
+	fmt.Println("Press Ctrl+C to stop...")
+
+	// Wait for interrupt signal
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+	<-c
+
+	fmt.Println("\nShutting down...")
+	wgDevice.Down()
+} 

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1753432016,
+        "narHash": "sha256-cnL5WWn/xkZoyH/03NNUS7QgW5vI7D1i74g48qplCvg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6027c30c8e9810896b92429f0092f624f7b1aace",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,147 @@
+{
+  description = "WireGuard Go development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+        
+        # Go version matching go.mod
+        go = pkgs.go_1_23;
+        
+        # Additional Go tools for development
+        goTools = with pkgs; [
+          # Core Go toolchain
+          go
+          
+          # Language Server Protocol
+          gopls
+          
+          # Formatting and imports
+          # gofmt
+          # goimports
+          gofumpt  # Stricter gofmt
+          
+          # Linting and static analysis
+          golangci-lint
+          gosec      # Security checker
+          ineffassign
+          
+          # Debugging
+          delve
+          
+          # Code generation and refactoring
+          gotests       # Generate tests
+          gomodifytags  # Modify struct tags
+          impl          # Generate interface implementations
+          govulncheck   # Vulnerability scanner
+          
+          # Build and development tools
+          air           # Live reload
+          gotools       # Various tools (guru, gorename, etc.)
+          
+          # Testing and benchmarking
+          gotestsum     # Pretty test output
+          
+          # Documentation
+          # godoc
+        ];
+        
+        # System tools
+        systemTools = with pkgs; [
+          git
+          gnumake
+          direnv
+          nix-direnv
+          
+          # Networking tools (useful for WireGuard development)
+          iproute2
+          iptables
+          wireguard-tools
+          
+          # Text processing
+          jq
+          yq-go
+          
+          # Shell and utilities
+          fish
+          ripgrep
+          fd
+          tree
+        ];
+
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = goTools ++ systemTools;
+          
+          shellHook = ''
+            echo "🚀 WireGuard Go development environment loaded!"
+            echo "📦 Go version: $(go version)"
+            echo "🔧 Available tools:"
+            echo "  • LSP: gopls"
+            echo "  • Linting: golangci-lint, staticcheck, gosec"
+            echo "  • Formatting: gofmt, goimports, gofumpt"
+            echo "  • Debugging: delve (dlv)"
+            echo "  • Testing: gotests, gotestsum"
+            echo "  • Security: govulncheck"
+            echo "  • Live reload: air"
+            echo ""
+            echo "💡 Quick commands:"
+            echo "  • go mod tidy          # Clean dependencies"
+            echo "  • golangci-lint run    # Run all linters"
+            echo "  • govulncheck ./...    # Check for vulnerabilities"
+            echo "  • gotests -all         # Generate tests"
+            echo "  • air                  # Live reload server"
+            echo ""
+            
+            # Set up Go environment
+            export GOPATH="$PWD/.go"
+            export GOBIN="$GOPATH/bin"
+            export PATH="$GOBIN:$PATH"
+            
+            # Create necessary directories
+            mkdir -p "$GOPATH/bin"
+            
+            # Set Go build cache to project directory
+            export GOCACHE="$PWD/.gocache"
+            mkdir -p "$GOCACHE"
+            
+            # Ensure proper Go module mode
+            export GO111MODULE=on
+            
+            # Development-friendly settings
+            export GOTOOLCHAIN="go1.23.1"
+            export CGO_ENABLED=1
+            
+            # WireGuard specific
+            export WG_COLOR_MODE=always
+          '';
+          
+          # Environment variables for tools
+          CGO_ENABLED = "1";
+          GO111MODULE = "on";
+          GOFLAGS = "-buildvcs=false";  # Disable VCS stamping for reproducible builds
+        };
+        
+        # Optional: Create a package for the WireGuard binary
+        packages.default = pkgs.buildGoModule {
+          pname = "wireguard-go";
+          version = "0.0.0-dev";
+          src = ./.;
+          vendorHash = null;  # Let Nix handle dependencies
+          
+          meta = with pkgs.lib; {
+            description = "Userspace Go implementation of WireGuard";
+            homepage = "https://www.wireguard.com/";
+            license = licenses.mit;
+            platforms = platforms.linux ++ platforms.darwin;
+          };
+        };
+      });
+} 

rwcancel/rwcancel.go

@@ -64,7 +64,7 @@ func (rw *RWCancel) ReadyRead() bool {
 
 func (rw *RWCancel) ReadyWrite() bool {
 	closeFd := int32(rw.closingReader.Fd())
-	pollFds := []unix.PollFd{{Fd: int32(rw.fd), Events: unix.POLLOUT}, {Fd: closeFd, Events: unix.POLLOUT}}
+	pollFds := []unix.PollFd{{Fd: int32(rw.fd), Events: unix.POLLOUT}, {Fd: closeFd, Events: unix.POLLIN}}
 	var err error
 	for {
 		_, err = unix.Poll(pollFds, -1)

version.go

@@ -1,3 +1,3 @@
 package main
 
-const Version = "0.0.20230223"
+const Version = "0.0.20250522"