Delete pluto2.go

1 files changed, 0 insertions, 851 deletions

diff --git a/pluto2.go b/pluto2.go
deleted file mode 100644
index 137c8e0..0000000
--- a/pluto2.go
+++ /dev/null
@@ -1,851 +0,0 @@
-package main
-
-import (
-        "bytes"
-        "crypto/rand"
-        "crypto/sha512"
-        "encoding/base64"
-        "encoding/binary"
-        "errors"
-        "flag"
-        "fmt"
-        "io"
-        "log"
-        "math"
-        "math/big"
-        "net"
-        "net/smtp"
-        "net/textproto"
-        "regexp"
-        "strings"
-        "sync"
-        "time"
-
-        "golang.org/x/net/proxy"
-)
-
-const (
-        TorSocksProxyAddr      = "127.0.0.1:9050"
-        RelayWorkerCount       = 5
-        DeliveryTimeout        = 30 * time.Second
-        MixnetBatchWindow      = 30 * time.Second
-        CoverTrafficInterval   = 15 * time.Second
-        MessageIDCacheDuration = 24 * time.Hour
-        PaddingSizeUnit        = 8 * 1024
-        MinDelay               = 100 * time.Millisecond
-        MaxDelay               = 2 * time.Second
-        RateLimitPerIP         = 10
-        RateLimitWindow        = 1 * time.Minute
-        MXLookupTimeout        = 5 * time.Second
-)
-
-var (
-        emailRegExp    *regexp.Regexp
-        localPartRegex *regexp.Regexp
-        domainRegex    *regexp.Regexp
-)
-
-func init() {
-        emailRegExp = regexp.MustCompile(`^[a-zA-Z0-9._%+=\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}$`)
-        localPartRegex = regexp.MustCompile(`^[a-zA-Z0-9._+=\-]+$`)
-        domainRegex = regexp.MustCompile(`^[a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?(\.[a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?)*$`)
-}
-
-func validateLocalPart(localPart string) error {
-        if len(localPart) == 0 || len(localPart) > 64 {
-                return errors.New("local part must be 1-64 characters")
-        }
-        if strings.HasPrefix(localPart, ".") || strings.HasSuffix(localPart, ".") {
-                return errors.New("local part cannot start or end with a dot")
-        }
-        if strings.Contains(localPart, "..") {
-                return errors.New("local part cannot contain consecutive dots")
-        }
-        if !localPartRegex.MatchString(localPart) {
-                return errors.New("local part contains invalid characters")
-        }
-        return nil
-}
-
-func validateDomain(domain string) error {
-        domain = strings.ToLower(strings.TrimSpace(domain))
-        if strings.HasSuffix(domain, ".") {
-                domain = domain[:len(domain)-1]
-        }
-        if len(domain) == 0 || len(domain) > 253 {
-                return errors.New("domain must be 1-253 characters")
-        }
-        if isOnionDomain(domain) {
-                onionName := strings.TrimSuffix(domain, ".onion")
-                if len(onionName) != 16 && len(onionName) != 56 {
-                        return errors.New("invalid .onion domain length")
-                }
-                validOnion := regexp.MustCompile(`^[a-z2-7]+$`)
-                if !validOnion.MatchString(onionName) {
-                        return errors.New("invalid .onion domain format")
-                }
-                return nil
-        }
-        if !domainRegex.MatchString(domain) {
-                return errors.New("invalid domain format")
-        }
-        labels := strings.Split(domain, ".")
-        if len(labels) < 2 {
-                return errors.New("domain must have at least two labels")
-        }
-        for _, label := range labels {
-                if len(label) == 0 || len(label) > 63 {
-                        return errors.New("domain label must be 1-63 characters")
-                }
-        }
-        return nil
-}
-
-func ValidateEmailAddress(address string) (string, string, error) {
-        address = strings.TrimSpace(address)
-        address = strings.Trim(address, "<>")
-        if !strings.Contains(address, "@") {
-                return "", "", errors.New("invalid email address: missing '@'")
-        }
-        sepInd := strings.LastIndex(address, "@")
-        if sepInd == 0 || sepInd == len(address)-1 {
-                return "", "", errors.New("invalid email address: empty local part or domain")
-        }
-        localPart := address[:sepInd]
-        domain := address[sepInd+1:]
-        if err := validateLocalPart(localPart); err != nil {
-                return "", "", fmt.Errorf("invalid local part: %w", err)
-        }
-        if err := validateDomain(domain); err != nil {
-                return "", "", fmt.Errorf("invalid domain: %w", err)
-        }
-        return localPart, domain, nil
-}
-
-func validateServerName(name string) error {
-        name = strings.TrimSpace(name)
-        if name == "" {
-                return errors.New("server name cannot be empty")
-        }
-        if !isOnionDomain(name) {
-                return errors.New("server name must be a .onion domain")
-        }
-        onionName := strings.TrimSuffix(strings.ToLower(name), ".onion")
-        if len(onionName) != 56 {
-                return errors.New("server name must be a v3 .onion address (56 characters)")
-        }
-        validOnionV3 := regexp.MustCompile(`^[a-z2-7]{56}$`)
-        if !validOnionV3.MatchString(onionName) {
-                return errors.New("invalid v3 .onion address format")
-        }
-        return nil
-}
-
-func hasMXRecords(domain string) bool {
-        domain = strings.ToLower(strings.TrimSpace(domain))
-        if strings.HasSuffix(domain, ".") {
-                domain = domain[:len(domain)-1]
-        }
-        done := make(chan bool, 1)
-        var hasMX bool
-        go func() {
-                mxRecords, err := net.LookupMX(domain)
-                hasMX = err == nil && len(mxRecords) > 0
-                done <- true
-        }()
-        select {
-        case <-done:
-                return hasMX
-        case <-time.After(MXLookupTimeout):
-                return false
-        }
-}
-
-type MessageIDCache struct {
-        cache map[string]time.Time
-        mu    sync.RWMutex
-}
-
-func NewMessageIDCache() *MessageIDCache {
-        cache := &MessageIDCache{cache: make(map[string]time.Time)}
-        go cache.cleanupLoop()
-        return cache
-}
-
-func (c *MessageIDCache) Has(messageID string) bool {
-        c.mu.RLock()
-        defer c.mu.RUnlock()
-        expiry, exists := c.cache[messageID]
-        if !exists {
-                return false
-        }
-        return time.Now().Before(expiry)
-}
-
-func (c *MessageIDCache) Add(messageID string) bool {
-        c.mu.Lock()
-        defer c.mu.Unlock()
-        if _, exists := c.cache[messageID]; exists {
-                return false
-        }
-        c.cache[messageID] = time.Now().Add(MessageIDCacheDuration)
-        return true
-}
-
-func (c *MessageIDCache) cleanupLoop() {
-        ticker := time.NewTicker(1 * time.Hour)
-        defer ticker.Stop()
-        for range ticker.C {
-                c.mu.Lock()
-                now := time.Now()
-                for id, expiry := range c.cache {
-                        if now.After(expiry) {
-                                delete(c.cache, id)
-                        }
-                }
-                c.mu.Unlock()
-        }
-}
-
-type RateLimiter struct {
-        requests map[string][]time.Time
-        mu       sync.RWMutex
-}
-
-func NewRateLimiter() *RateLimiter {
-        limiter := &RateLimiter{requests: make(map[string][]time.Time)}
-        go limiter.cleanupLoop()
-        return limiter
-}
-
-func (rl *RateLimiter) Allow(clientIP string) bool {
-        rl.mu.Lock()
-        defer rl.mu.Unlock()
-        now := time.Now()
-        cutoff := now.Add(-RateLimitWindow)
-        requests := rl.requests[clientIP]
-        var validRequests []time.Time
-        for _, t := range requests {
-                if t.After(cutoff) {
-                        validRequests = append(validRequests, t)
-                }
-        }
-        if len(validRequests) >= RateLimitPerIP {
-                rl.requests[clientIP] = validRequests
-                return false
-        }
-        validRequests = append(validRequests, now)
-        rl.requests[clientIP] = validRequests
-        return true
-}
-
-func (rl *RateLimiter) cleanupLoop() {
-        ticker := time.NewTicker(5 * time.Minute)
-        defer ticker.Stop()
-        for range ticker.C {
-                rl.mu.Lock()
-                now := time.Now()
-                cutoff := now.Add(-RateLimitWindow)
-                for ip, requests := range rl.requests {
-                        var validRequests []time.Time
-                        for _, t := range requests {
-                                if t.After(cutoff) {
-                                        validRequests = append(validRequests, t)
-                                }
-                        }
-                        if len(validRequests) == 0 {
-                                delete(rl.requests, ip)
-                        } else {
-                                rl.requests[ip] = validRequests
-                        }
-                }
-                rl.mu.Unlock()
-        }
-}
-
-func ApplyAdaptivePadding(data []byte) []byte {
-        originalLen := len(data)
-        targetSize := ((originalLen / PaddingSizeUnit) + 1) * PaddingSizeUnit
-        if originalLen >= targetSize {
-                return data
-        }
-        padded := make([]byte, targetSize)
-        copy(padded, data)
-        paddingLen := targetSize - originalLen
-        padding := make([]byte, paddingLen)
-        rand.Read(padding)
-        copy(padded[originalLen:], padding)
-        return padded
-}
-
-func RandomDelay() {
-        delayNs := MinDelay.Nanoseconds() + int64(cryptoRandInt63n(MaxDelay.Nanoseconds()-MinDelay.Nanoseconds()))
-        time.Sleep(time.Duration(delayNs))
-}
-
-func cryptoRandInt63n(n int64) int64 {
-        if n <= 0 {
-                return 0
-        }
-        max := big.NewInt(n)
-        result, _ := rand.Int(rand.Reader, max)
-        return result.Int64()
-}
-
-type MixnetBatcher struct {
-        batch       []*Envelope
-        batchMu     sync.Mutex
-        outputQueue chan *Envelope
-        stopChan    chan struct{}
-}
-
-func NewMixnetBatcher(outputQueue chan *Envelope) *MixnetBatcher {
-        batcher := &MixnetBatcher{
-                batch:       make([]*Envelope, 0),
-                outputQueue: outputQueue,
-                stopChan:    make(chan struct{}),
-        }
-        go batcher.batchLoop()
-        return batcher
-}
-
-func (mb *MixnetBatcher) Add(envelope *Envelope) {
-        mb.batchMu.Lock()
-        mb.batch = append(mb.batch, envelope)
-        mb.batchMu.Unlock()
-}
-
-func (mb *MixnetBatcher) batchLoop() {
-        ticker := time.NewTicker(MixnetBatchWindow)
-        defer ticker.Stop()
-        for {
-                select {
-                case <-ticker.C:
-                        mb.processBatch()
-                case <-mb.stopChan:
-                        return
-                }
-        }
-}
-
-func (mb *MixnetBatcher) processBatch() {
-        mb.batchMu.Lock()
-        if len(mb.batch) == 0 {
-                mb.batchMu.Unlock()
-                return
-        }
-        batch := make([]*Envelope, len(mb.batch))
-        copy(batch, mb.batch)
-        mb.batch = make([]*Envelope, 0)
-        mb.batchMu.Unlock()
-        shuffleBatch(batch)
-        for _, env := range batch {
-                RandomDelay()
-                select {
-                case mb.outputQueue <- env:
-                default:
-                }
-        }
-}
-
-func shuffleBatch(batch []*Envelope) {
-        for i := len(batch) - 1; i > 0; i-- {
-                j := int(cryptoRandInt63n(int64(i + 1)))
-                batch[i], batch[j] = batch[j], batch[i]
-        }
-}
-
-func (mb *MixnetBatcher) Stop() {
-        close(mb.stopChan)
-}
-
-type CoverTrafficGenerator struct {
-        outputQueue chan *Envelope
-        stopChan    chan struct{}
-}
-
-func NewCoverTrafficGenerator(outputQueue chan *Envelope) *CoverTrafficGenerator {
-        gen := &CoverTrafficGenerator{
-                outputQueue: outputQueue,
-                stopChan:    make(chan struct{}),
-        }
-        go gen.generateLoop()
-        return gen
-}
-
-func (ctg *CoverTrafficGenerator) generateLoop() {
-        ticker := time.NewTicker(CoverTrafficInterval)
-        defer ticker.Stop()
-        firstNames := []string{"john", "mary", "david", "sarah", "mike", "emma", "james", "lisa", "robert", "anna"}
-        lastNames := []string{"smith", "johnson", "williams", "brown", "jones", "garcia", "miller", "davis", "rodriguez", "martinez"}
-        for {
-                select {
-                case <-ticker.C:
-                        firstName := firstNames[cryptoRandInt63n(int64(len(firstNames)))]
-                        lastName := lastNames[cryptoRandInt63n(int64(len(lastNames)))]
-                        randomNum := cryptoRandInt63n(9999)
-                        var dummyAddr string
-                        switch cryptoRandInt63n(3) {
-                        case 0:
-                                dummyAddr = fmt.Sprintf("%s.%s%d@gmail.com", firstName, lastName, randomNum)
-                        case 1:
-                                dummyAddr = fmt.Sprintf("%s%s%d@gmail.com", firstName, lastName, randomNum)
-                        default:
-                                dummyAddr = fmt.Sprintf("%s.%s@gmail.com", firstName, lastName)
-                        }
-                        dummyData := make([]byte, 1024+int(cryptoRandInt63n(2048)))
-                        rand.Read(dummyData)
-                        envelope := &Envelope{
-                                MessageFrom:    fmt.Sprintf("noreply%d@notifications.com", cryptoRandInt63n(999)),
-                                MessageTo:      dummyAddr,
-                                MessageData:    bytes.NewReader(dummyData),
-                                ReceivedAt:     time.Now(),
-                                RetryCount:     0,
-                                IsCoverTraffic: true,
-                        }
-                        select {
-                        case ctg.outputQueue <- envelope:
-                        default:
-                        }
-                case <-ctg.stopChan:
-                        return
-                }
-        }
-}
-
-func (ctg *CoverTrafficGenerator) Stop() {
-        close(ctg.stopChan)
-}
-
-type Server struct {
-        Name           string
-        Addr           string
-        Handler        Handler
-        MessageIDCache *MessageIDCache
-        RateLimiter    *RateLimiter
-        MixnetBatcher  *MixnetBatcher
-        CoverTraffic   *CoverTrafficGenerator
-}
-
-type conn struct {
-        remoteAddr    string
-        server        *Server
-        rwc           net.Conn
-        text          *textproto.Conn
-        fromAgent     string
-        mailFrom      string
-        mailTo        []string
-        mailData      *bytes.Buffer
-        helloReceived bool
-        quitSent      bool
-        mu            sync.Mutex
-}
-
-type Envelope struct {
-        MessageFrom    string
-        MessageTo      string
-        MessageData    io.Reader
-        ReceivedAt     time.Time
-        RetryCount     int
-        MessageID      string
-        IsCoverTraffic bool
-}
-
-type HandlerFunc func(envelope *Envelope) error
-
-func (f HandlerFunc) ServeSMTP(envelope *Envelope) error {
-        return f(envelope)
-}
-
-type Handler interface {
-        ServeSMTP(envelope *Envelope) error
-}
-
-var (
-        mailQueue      chan *Envelope
-        mailQueueMutex sync.Mutex
-)
-
-func (srv *Server) newConn(rwc net.Conn) (*conn, error) {
-        c := &conn{
-                remoteAddr: rwc.RemoteAddr().String(),
-                server:     srv,
-                rwc:        rwc,
-                text:       textproto.NewConn(rwc),
-                mailTo:     make([]string, 0),
-        }
-        return c, nil
-}
-
-func (srv *Server) ListenAndServe() error {
-        if srv.Name == "" {
-                srv.Name = "localhost"
-        }
-        addr := srv.Addr
-        if addr == "" {
-                addr = ":2525"
-        }
-        ln, err := net.Listen("tcp", addr)
-        if err != nil {
-                return err
-        }
-        return srv.Serve(ln)
-}
-
-func (srv *Server) Serve(l net.Listener) error {
-        defer l.Close()
-        var tempDelay time.Duration
-        for {
-                rw, e := l.Accept()
-                if e != nil {
-                        if ne, ok := e.(net.Error); ok && ne.Temporary() {
-                                if tempDelay == 0 {
-                                        tempDelay = 5 * time.Millisecond
-                                } else {
-                                        tempDelay *= 2
-                                }
-                                if max := 1 * time.Second; tempDelay > max {
-                                        tempDelay = max
-                                }
-                                time.Sleep(tempDelay)
-                                continue
-                        }
-                        return e
-                }
-                tempDelay = 0
-                c, err := srv.newConn(rw)
-                if err != nil {
-                        continue
-                }
-                go c.serve()
-        }
-}
-
-func (c *conn) serve() {
-        clientIP := extractIP(c.remoteAddr)
-        if !c.server.RateLimiter.Allow(clientIP) {
-                RandomDelay()
-                c.text.Close()
-                c.rwc.Close()
-                return
-        }
-        RandomDelay()
-        err := c.text.PrintfLine("%d %s ESMTP", 220, c.server.Name)
-        if err != nil {
-                return
-        }
-        for !c.quitSent && err == nil {
-                err = c.readCommand()
-        }
-        c.text.Close()
-        c.rwc.Close()
-}
-
-func extractIP(addr string) string {
-        host, _, err := net.SplitHostPort(addr)
-        if err != nil {
-                return addr
-        }
-        return host
-}
-
-func (c *conn) resetSession() {
-        c.mailFrom = ""
-        c.mailTo = make([]string, 0)
-        c.mailData = nil
-}
-
-func isOnionDomain(domain string) bool {
-        domain = strings.ToLower(strings.TrimSpace(domain))
-        if domain == "" {
-                return false
-        }
-        if strings.HasSuffix(domain, ".") {
-                domain = domain[:len(domain)-1]
-        }
-        return strings.HasSuffix(domain, ".onion")
-}
-
-func SplitAddress(address string) (string, string, error) {
-        localPart, domain, err := ValidateEmailAddress(address)
-        if err != nil {
-                return "", "", err
-        }
-        if !isOnionDomain(domain) {
-                return "", "", errors.New("only .onion domains are allowed for relay")
-        }
-        return localPart, domain, nil
-}
-
-func extractDomainFromAddress(address string) string {
-        sepInd := strings.LastIndex(address, "@")
-        if sepInd == -1 {
-                return ""
-        }
-        return address[sepInd+1:]
-}
-
-func (c *conn) readCommand() error {
-        s, err := c.text.ReadLine()
-        if err != nil {
-                return err
-        }
-        RandomDelay()
-        parts := strings.Split(s, " ")
-        if len(parts) <= 0 {
-                return c.text.PrintfLine("%d %s", 500, "Command not recognized")
-        }
-        parts[0] = strings.ToUpper(parts[0])
-        switch parts[0] {
-        case "HELO", "EHLO":
-                if len(parts) < 2 {
-                        return c.text.PrintfLine("%d %s", 501, "Not enough arguments")
-                }
-                c.fromAgent = parts[1]
-                c.resetSession()
-                c.helloReceived = true
-                responses := []string{
-                        fmt.Sprintf("%d-%s", 250, c.server.Name),
-                        fmt.Sprintf("%d-%s", 250, "PIPELINING"),
-                        fmt.Sprintf("%d %s", 250, "SMTPUTF8"),
-                }
-                for i, resp := range responses {
-                        if i == len(responses)-1 {
-                                resp = strings.Replace(resp, "-", " ", 1)
-                        }
-                        if err := c.text.PrintfLine(resp); err != nil {
-                                return err
-                        }
-                }
-                return nil
-        case "MAIL":
-                if c.mailFrom != "" {
-                        return c.text.PrintfLine("%d %s", 503, "MAIL command already received")
-                }
-                if len(parts) < 2 {
-                        return c.text.PrintfLine("%d %s", 501, "Not enough arguments")
-                }
-                if !strings.HasPrefix(strings.ToUpper(parts[1]), "FROM:") {
-                        return c.text.PrintfLine("%d %s", 501, "MAIL command must be immediately succeeded by 'FROM:'")
-                }
-                from := strings.TrimPrefix(parts[1], "FROM:")
-                from = strings.TrimPrefix(from, "from:")
-                from = strings.Trim(from, "<>")
-                if !emailRegExp.MatchString(from) {
-                        return c.text.PrintfLine("%d %s", 501, "MAIL command contained invalid address")
-                }
-                _, _, err := ValidateEmailAddress(from)
-                if err != nil {
-                        return c.text.PrintfLine("%d %s", 501, "Invalid email address format")
-                }
-                c.mailFrom = from
-                return c.text.PrintfLine("%d %s", 250, "Ok")
-        case "RCPT":
-                if c.mailFrom == "" {
-                        return c.text.PrintfLine("%d %s", 503, "Bad sequence of commands")
-                }
-                if len(parts) < 2 {
-                        return c.text.PrintfLine("%d %s", 501, "Not enough arguments")
-                }
-                if !strings.HasPrefix(strings.ToUpper(parts[1]), "TO:") {
-                        return c.text.PrintfLine("%d %s", 501, "RCPT command must be immediately succeeded by 'TO:'")
-                }
-                to := strings.TrimPrefix(parts[1], "TO:")
-                to = strings.TrimPrefix(to, "to:")
-                to = strings.Trim(to, "<>")
-                if !emailRegExp.MatchString(to) {
-                        return c.text.PrintfLine("%d %s", 501, "RCPT command contained invalid address")
-                }
-                _, domain, err := ValidateEmailAddress(to)
-                if err != nil {
-                        return c.text.PrintfLine("%d %s", 501, "Invalid email address format")
-                }
-                if !isOnionDomain(domain) {
-                        if !hasMXRecords(domain) {
-                                return c.text.PrintfLine("%d %s", 550, "Mailbox unavailable")
-                        }
-                }
-                c.mailTo = append(c.mailTo, to)
-                return c.text.PrintfLine("%d %s", 250, "Ok")
-        case "DATA":
-                if len(c.mailTo) == 0 || c.mailFrom == "" {
-                        return c.text.PrintfLine("%d %s", 503, "Bad sequence of commands")
-                }
-                if err := c.text.PrintfLine("%d %s", 354, "End data with <CR><LF>.<CR><LF>"); err != nil {
-                        return err
-                }
-                data, err := c.text.ReadDotBytes()
-                if err != nil {
-                        return err
-                }
-                c.mailData = bytes.NewBuffer(data)
-                messageID := generateMessageID()
-                if c.server.MessageIDCache.Has(messageID) {
-                        return c.text.PrintfLine("%d %s", 554, "Duplicate message detected")
-                }
-                c.server.MessageIDCache.Add(messageID)
-                for _, recipient := range c.mailTo {
-                        env := &Envelope{
-                                MessageFrom:    c.mailFrom,
-                                MessageTo:      recipient,
-                                MessageData:    bytes.NewReader(c.mailData.Bytes()),
-                                ReceivedAt:     time.Now(),
-                                RetryCount:     0,
-                                MessageID:      messageID,
-                                IsCoverTraffic: false,
-                        }
-                        if err := c.server.Handler.ServeSMTP(env); err != nil {
-                                return c.text.PrintfLine("%d %s", 554, "Transaction failed")
-                        }
-                }
-                c.resetSession()
-                return c.text.PrintfLine("%d %s", 250, "OK")
-        case "RSET":
-                c.resetSession()
-                return c.text.PrintfLine("%d %s", 250, "Ok")
-        case "VRFY", "EXPN", "HELP", "NOOP":
-                return c.text.PrintfLine("%d %s", 250, "OK")
-        case "QUIT":
-                c.quitSent = true
-                return c.text.PrintfLine("%d %s", 221, "Bye")
-        default:
-                return c.text.PrintfLine("%d %s", 500, "Command not recognized")
-        }
-}
-
-func generateMessageID() string {
-        randomBytes := make([]byte, 32)
-        rand.Read(randomBytes)
-        timestamp := make([]byte, 8)
-        binary.BigEndian.PutUint64(timestamp, uint64(time.Now().UnixNano()))
-        combined := append(randomBytes, timestamp...)
-        h := sha512.Sum512(combined)
-        return base64.URLEncoding.EncodeToString(h[:32])
-}
-
-type SimpleHandler struct {
-        batcher *MixnetBatcher
-}
-
-func (h *SimpleHandler) ServeSMTP(envelope *Envelope) error {
-        h.batcher.Add(envelope)
-        return nil
-}
-
-func smtpRelay(envelope *Envelope) error {
-        if envelope.IsCoverTraffic {
-                return nil
-        }
-        _, domain, err := SplitAddress(envelope.MessageTo)
-        if err != nil {
-                return fmt.Errorf("invalid recipient address: %w", err)
-        }
-        targetAddr := net.JoinHostPort(domain, "25")
-        jitter := time.Duration(cryptoRandInt63n(int64(5 * time.Second)))
-        time.Sleep(jitter)
-        dialer := &net.Dialer{Timeout: DeliveryTimeout}
-        torDialer, err := proxy.SOCKS5("tcp", TorSocksProxyAddr, nil, dialer)
-        if err != nil {
-                return fmt.Errorf("failed to create Tor dialer: %w", err)
-        }
-        conn, err := torDialer.Dial("tcp", targetAddr)
-        if err != nil {
-                return fmt.Errorf("failed to connect to relay target: %w", err)
-        }
-        defer conn.Close()
-        conn.SetDeadline(time.Now().Add(DeliveryTimeout))
-        client, err := smtp.NewClient(conn, domain)
-        if err != nil {
-                return fmt.Errorf("failed to create SMTP client: %w", err)
-        }
-        defer client.Close()
-        if err := client.Mail(envelope.MessageFrom); err != nil {
-                return fmt.Errorf("MAIL FROM failed: %w", err)
-        }
-        if err := client.Rcpt(envelope.MessageTo); err != nil {
-                return fmt.Errorf("RCPT TO failed: %w", err)
-        }
-        wc, err := client.Data()
-        if err != nil {
-                return fmt.Errorf("DATA command failed: %w", err)
-        }
-        defer wc.Close()
-        if _, err := io.Copy(wc, envelope.MessageData); err != nil {
-                return fmt.Errorf("message transfer failed: %w", err)
-        }
-        return nil
-}
-
-func queueEnvelope(envelope *Envelope) bool {
-        mailQueueMutex.Lock()
-        defer mailQueueMutex.Unlock()
-        select {
-        case mailQueue <- envelope:
-                return true
-        default:
-                return false
-        }
-}
-
-func StartRelayWorkers(queue chan *Envelope, workerCount int) {
-        for i := 0; i < workerCount; i++ {
-                go func(id int) {
-                        log.Printf("Relay worker %d started", id)
-                        for env := range queue {
-                                err := smtpRelay(env)
-                                if err != nil {
-                                        domain := extractDomainFromAddress(env.MessageTo)
-                                        if isOnionDomain(domain) && env.RetryCount < 9 {
-                                                env.RetryCount++
-                                                backoff := time.Duration(math.Pow(2, float64(env.RetryCount))) * time.Second
-                                                jitter := time.Duration(cryptoRandInt63n(int64(backoff / 2)))
-                                                time.Sleep(backoff + jitter)
-                                                queueEnvelope(env)
-                                        }
-                                }
-                        }
-                }(i)
-        }
-}
-
-func main() {
-        listenAddr := flag.String("addr", "127.0.0.1:2525", "Listen address")
-        serverName := flag.String("name", "abcdefghijklmnopqrstuvwxyz234567abcdefghijklmnopqrstuv.onion", "Server v3 .onion hostname")
-        flag.Parse()
-        if err := validateServerName(*serverName); err != nil {
-                log.Fatalf("Invalid server name: %v", err)
-        }
-        mailQueue = make(chan *Envelope, 100)
-        StartRelayWorkers(mailQueue, RelayWorkerCount)
-        messageIDCache := NewMessageIDCache()
-        rateLimiter := NewRateLimiter()
-        mixnetBatcher := NewMixnetBatcher(mailQueue)
-        coverTraffic := NewCoverTrafficGenerator(mailQueue)
-        server := &Server{
-                Name:           *serverName,
-                Addr:           *listenAddr,
-                MessageIDCache: messageIDCache,
-                RateLimiter:    rateLimiter,
-                MixnetBatcher:  mixnetBatcher,
-                CoverTraffic:   coverTraffic,
-        }
-        handler := &SimpleHandler{batcher: mixnetBatcher}
-        server.Handler = handler
-        log.Printf("Pluto2 SMTP Relay Server")
-        log.Printf("========================")
-        log.Printf("Server: %s", server.Name)
-        log.Printf("Listen: %s", server.Addr)
-        log.Printf("Tor proxy: %s", TorSocksProxyAddr)
-        log.Printf("")
-        log.Printf("Security: Replay protection, Rate limiting, Timing attacks, Size correlation, Mixnet batching, Cover traffic")
-        log.Printf("Validation: RFC-compliant email, v3 .onion server only")
-        log.Printf("Policy: FROM any valid, TO .onion + clearnet(MX), RELAY .onion only")
-        log.Printf("")
-        listener, err := net.Listen("tcp", server.Addr)
-        if err != nil {
-                log.Fatalf("Failed to create listener: %v", err)
-        }
-        if err := server.Serve(listener); err != nil {
-                log.Fatalf("Server failed: %v", err)
-        }
-}