Update README.md

[rbdr/mobius] / hotline / server.go

diff --git a/hotline/server.go b/hotline/server.go
index 62322539eed67e01f85f9d69b07f0defc8577756..ed3c04114d4dd28f590b243ae945f89957287dcf 100644 (file)
--- a/hotline/server.go
+++ b/hotline/server.go
@@ -9,13 +9,12 @@ import (
        "errors"
        "fmt"
        "golang.org/x/text/encoding/charmap"
        "errors"
        "fmt"
        "golang.org/x/text/encoding/charmap"

-       "gopkg.in/yaml.v3"
+       "golang.org/x/time/rate"

        "io"
        "log"
        "log/slog"
        "net"
        "os"
        "io"
        "log"
        "log/slog"
        "net"
        "os"

-       "path/filepath"

        "strings"
        "sync"
        "time"
        "strings"
        "sync"
        "time"


@@ -39,9 +38,12 @@ type Server struct {
        NetInterface string
        Port         int
 
        NetInterface string
        Port         int
 

-       Config    Config
-       ConfigDir string
-       Logger    *slog.Logger
+       rateLimiters map[string]*rate.Limiter
+
+       handlers map[TranType]HandlerFunc
+
+       Config Config
+       Logger *slog.Logger

 
        TrackerPassID [4]byte
 
 
        TrackerPassID [4]byte
 


@@ -51,10 +53,8 @@ type Server struct {
 
        outbox chan Transaction
 
 
        outbox chan Transaction
 

-       // TODO
-       Agreement []byte
-       banner    []byte
-       // END TODO
+       Agreement io.ReadSeeker
+       Banner    []byte

 
        FileTransferMgr FileTransferMgr
        ChatMgr         ChatManager
 
        FileTransferMgr FileTransferMgr
        ChatMgr         ChatManager


@@ -66,60 +66,58 @@ type Server struct {
        MessageBoard io.ReadWriteSeeker
 }
 
        MessageBoard io.ReadWriteSeeker
 }
 

-// NewServer constructs a new Server from a config dir
-func NewServer(config Config, configDir, netInterface string, netPort int, logger *slog.Logger, fs FileStore) (*Server, error) {
-       server := Server{
-               NetInterface:    netInterface,
-               Port:            netPort,
-               Config:          config,
-               ConfigDir:       configDir,
-               Logger:          logger,
-               outbox:          make(chan Transaction),
-               Stats:           NewStats(),
-               FS:              fs,
-               ChatMgr:         NewMemChatManager(),
-               ClientMgr:       NewMemClientMgr(),
-               FileTransferMgr: NewMemFileTransferMgr(),
-       }
+type Option = func(s *Server)

 
 

-       // generate a new random passID for tracker registration
-       _, err := rand.Read(server.TrackerPassID[:])
-       if err != nil {
-               return nil, err
+func WithConfig(config Config) func(s *Server) {
+       return func(s *Server) {
+               s.Config = config

        }
        }

+}

 
 

-       server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
-       if err != nil {
-               return nil, err
+func WithLogger(logger *slog.Logger) func(s *Server) {
+       return func(s *Server) {
+               s.Logger = logger

        }
        }

+}

 
 

-       server.AccountManager, err = NewYAMLAccountManager(filepath.Join(configDir, "Users/"))
-       if err != nil {
-               return nil, fmt.Errorf("error loading accounts: %w", err)
+// WithPort optionally overrides the default TCP port.
+func WithPort(port int) func(s *Server) {
+       return func(s *Server) {
+               s.Port = port

        }
        }

+}

 
 

-       // If the FileRoot is an absolute path, use it, otherwise treat as a relative path to the config dir.
-       if !filepath.IsAbs(server.Config.FileRoot) {
-               server.Config.FileRoot = filepath.Join(configDir, server.Config.FileRoot)
+// WithInterface optionally sets a specific interface to listen on.
+func WithInterface(netInterface string) func(s *Server) {
+       return func(s *Server) {
+               s.NetInterface = netInterface

        }
        }

+}

 
 

-       server.banner, err = os.ReadFile(filepath.Join(server.ConfigDir, server.Config.BannerFile))
-       if err != nil {
-               return nil, fmt.Errorf("error opening banner: %w", err)
-       }
+type ServerConfig struct {
+}

 
 

-       if server.Config.EnableTrackerRegistration {
-               server.Logger.Info(
-                       "Tracker registration enabled",
-                       "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
-                       "trackers", server.Config.Trackers,
-               )
+func NewServer(options ...Option) (*Server, error) {
+       server := Server{
+               handlers:        make(map[TranType]HandlerFunc),
+               outbox:          make(chan Transaction),
+               rateLimiters:    make(map[string]*rate.Limiter),
+               FS:              &OSFileStore{},
+               ChatMgr:         NewMemChatManager(),
+               ClientMgr:       NewMemClientMgr(),
+               FileTransferMgr: NewMemFileTransferMgr(),
+               Stats:           NewStats(),
+       }

 
 

-               go server.registerWithTrackers()
+       for _, opt := range options {
+               opt(&server)

        }
 
        }
 

-       // Start Client Keepalive go routine
-       go server.keepaliveHandler()
+       // generate a new random passID for tracker registration
+       _, err := rand.Read(server.TrackerPassID[:])
+       if err != nil {
+               return nil, err
+       }

 
        return &server, nil
 }
 
        return &server, nil
 }


@@ -129,6 +127,10 @@ func (s *Server) CurrentStats() map[string]interface{} {
 }
 
 func (s *Server) ListenAndServe(ctx context.Context) error {
 }
 
 func (s *Server) ListenAndServe(ctx context.Context) error {

+       go s.registerWithTrackers(ctx)
+       go s.keepaliveHandler(ctx)
+       go s.processOutbox()
+

        var wg sync.WaitGroup
 
        wg.Add(1)
        var wg sync.WaitGroup
 
        wg.Add(1)


@@ -172,14 +174,14 @@ func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error
                        )
 
                        if err != nil {
                        )
 
                        if err != nil {

-                               s.Logger.Error("file transfer error", "reason", err)
+                               s.Logger.Error("file transfer error", "err", err)

                        }
                }()
        }
 }
 
 func (s *Server) sendTransaction(t Transaction) error {
                        }
                }()
        }
 }
 
 func (s *Server) sendTransaction(t Transaction) error {

-       client := s.ClientMgr.Get(t.clientID)
+       client := s.ClientMgr.Get(t.ClientID)

 
        if client == nil {
                return nil
 
        if client == nil {
                return nil


@@ -187,7 +189,7 @@ func (s *Server) sendTransaction(t Transaction) error {
 
        _, err := io.Copy(client.Connection, &t)
        if err != nil {
 
        _, err := io.Copy(client.Connection, &t)
        if err != nil {

-               return fmt.Errorf("failed to send transaction to client %v: %v", t.clientID, err)
+               return fmt.Errorf("failed to send transaction to client %v: %v", t.ClientID, err)

        }
 
        return nil
        }
 
        return nil


@@ -204,79 +206,134 @@ func (s *Server) processOutbox() {
        }
 }
 
        }
 }
 

-func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
-       go s.processOutbox()
+// perIPRateLimit controls how frequently an IP address can connect before being throttled.
+// 0.5 = 1 connection every 2 seconds
+const perIPRateLimit = rate.Limit(0.5)

 
 

+func (s *Server) Serve(ctx context.Context, ln net.Listener) error {

        for {
        for {

-               conn, err := ln.Accept()
-               if err != nil {
-                       s.Logger.Error("error accepting connection", "err", err)
-               }
-               connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
-                       remoteAddr: conn.RemoteAddr().String(),
-               })
+               select {
+               case <-ctx.Done():
+                       s.Logger.Info("Server shutting down")
+                       return ctx.Err()
+               default:
+                       conn, err := ln.Accept()
+                       if err != nil {
+                               s.Logger.Error("Error accepting connection", "err", err)
+                               continue
+                       }

 
 

-               go func() {
-                       s.Logger.Info("Connection established", "RemoteAddr", conn.RemoteAddr())
-
-                       defer conn.Close()
-                       if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
-                               if err == io.EOF {
-                                       s.Logger.Info("Client disconnected", "RemoteAddr", conn.RemoteAddr())
-                               } else {
-                                       s.Logger.Error("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
+                       go func() {
+                               ipAddr := strings.Split(conn.RemoteAddr().(*net.TCPAddr).String(), ":")[0]
+
+                               connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
+                                       remoteAddr: conn.RemoteAddr().String(),
+                               })
+
+                               s.Logger.Info("Connection established", "ip", ipAddr)
+                               defer conn.Close()
+
+                               // Check if we have an existing rate limit for the IP and create one if we do not.
+                               rl, ok := s.rateLimiters[ipAddr]
+                               if !ok {
+                                       rl = rate.NewLimiter(perIPRateLimit, 1)
+                                       s.rateLimiters[ipAddr] = rl

                                }
                                }

-                       }
-               }()
+
+                               // Check if the rate limit is exceeded and close the connection if so.
+                               if !rl.Allow() {
+                                       s.Logger.Info("Rate limit exceeded", "RemoteAddr", conn.RemoteAddr())
+                                       conn.Close()
+                                       return
+                               }
+
+                               if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
+                                       if err == io.EOF {
+                                               s.Logger.Info("Client disconnected", "RemoteAddr", conn.RemoteAddr())
+                                       } else {
+                                               s.Logger.Error("Error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
+                                       }
+                               }
+                       }()
+               }

        }
 }
 
        }
 }
 

-const (
-       agreementFile = "Agreement.txt"
-)
+// time in seconds between tracker re-registration
+const trackerUpdateFrequency = 300
+
+// registerWithTrackers runs every trackerUpdateFrequency seconds to update the server's tracker entry on all configured
+// trackers.
+func (s *Server) registerWithTrackers(ctx context.Context) {
+       if s.Config.EnableTrackerRegistration {
+               s.Logger.Info("Tracker registration enabled", "trackers", s.Config.Trackers)
+       }

 
 

-func (s *Server) registerWithTrackers() {

        for {
        for {

-               tr := &TrackerRegistration{
-                       UserCount:   len(s.ClientMgr.List()),
-                       PassID:      s.TrackerPassID,
-                       Name:        s.Config.Name,
-                       Description: s.Config.Description,
-               }
-               binary.BigEndian.PutUint16(tr.Port[:], uint16(s.Port))
-               for _, t := range s.Config.Trackers {
-                       if err := register(&RealDialer{}, t, tr); err != nil {
-                               s.Logger.Error(fmt.Sprintf("unable to register with tracker %v", t), "error", err)
+               if s.Config.EnableTrackerRegistration {
+                       for _, t := range s.Config.Trackers {
+                               tr := &TrackerRegistration{
+                                       UserCount:   len(s.ClientMgr.List()),
+                                       PassID:      s.TrackerPassID,
+                                       Name:        s.Config.Name,
+                                       Description: s.Config.Description,
+                               }
+                               binary.BigEndian.PutUint16(tr.Port[:], uint16(s.Port))
+
+                               // Check the tracker string for a password.  This is janky but avoids a breaking change to the Config
+                               // Trackers field.
+                               splitAddr := strings.Split(":", t)
+                               if len(splitAddr) == 3 {
+                                       tr.Password = splitAddr[2]
+                               }
+
+                               if err := register(&RealDialer{}, t, tr); err != nil {
+                                       s.Logger.Error(fmt.Sprintf("Unable to register with tracker %v", t), "error", err)
+                               }

                        }
                }
                        }
                }

-
+               // Using time.Ticker with for/select would be more idiomatic, but it's super annoying that it doesn't tick on
+               // first pass.  Revist, maybe.
+               // https://github.com/golang/go/issues/17601

                time.Sleep(trackerUpdateFrequency * time.Second)
        }
 }
 
                time.Sleep(trackerUpdateFrequency * time.Second)
        }
 }
 

-// keepaliveHandler
-func (s *Server) keepaliveHandler() {
-       for {
-               time.Sleep(idleCheckInterval * time.Second)
-
-               for _, c := range s.ClientMgr.List() {
-                       c.mu.Lock()
-
-                       c.IdleTime += idleCheckInterval
+const (
+       userIdleSeconds   = 300 // time in seconds before an inactive user is marked idle
+       idleCheckInterval = 10  // time in seconds to check for idle users
+)

 
 

-                       // Check if the user
-                       if c.IdleTime > userIdleSeconds && !c.Flags.IsSet(UserFlagAway) {
-                               c.Flags.Set(UserFlagAway, 1)
+// keepaliveHandler runs every idleCheckInterval seconds and increments a user's idle time by idleCheckInterval seconds.
+// If the updated idle time exceeds userIdleSeconds and the user was not previously idle, we notify all connected clients
+// that the user has gone idle.  For most clients, this turns the user grey in the user list.
+func (s *Server) keepaliveHandler(ctx context.Context) {
+       ticker := time.NewTicker(idleCheckInterval * time.Second)
+       defer ticker.Stop()

 
 

-                               c.SendAll(
-                                       TranNotifyChangeUser,
-                                       NewField(FieldUserID, c.ID[:]),
-                                       NewField(FieldUserFlags, c.Flags[:]),
-                                       NewField(FieldUserName, c.UserName),
-                                       NewField(FieldUserIconID, c.Icon),
-                               )
+       for {
+               select {
+               case <-ctx.Done():
+                       return
+               case <-ticker.C:
+                       for _, c := range s.ClientMgr.List() {
+                               c.mu.Lock()
+                               c.IdleTime += idleCheckInterval
+
+                               // Check if the user
+                               if c.IdleTime > userIdleSeconds && !c.Flags.IsSet(UserFlagAway) {
+                                       c.Flags.Set(UserFlagAway, 1)
+
+                                       c.SendAll(
+                                               TranNotifyChangeUser,
+                                               NewField(FieldUserID, c.ID[:]),
+                                               NewField(FieldUserFlags, c.Flags[:]),
+                                               NewField(FieldUserName, c.UserName),
+                                               NewField(FieldUserIconID, c.Icon),
+                                       )
+                               }
+                               c.mu.Unlock()

                        }
                        }

-                       c.mu.Unlock()

                }
        }
 }
                }
        }
 }


@@ -296,18 +353,6 @@ func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *Clie
        return clientConn
 }
 
        return clientConn
 }
 

-// loadFromYAMLFile loads data from a YAML file into the provided data structure.
-func loadFromYAMLFile(path string, data interface{}) error {
-       fh, err := os.Open(path)
-       if err != nil {
-               return err
-       }
-       defer fh.Close()
-
-       decoder := yaml.NewDecoder(fh)
-       return decoder.Decode(data)
-}
-

 func sendBanMessage(rwc io.Writer, message string) {
        t := NewTransaction(
                TranServerMsg,
 func sendBanMessage(rwc io.Writer, message string) {
        t := NewTransaction(
                TranServerMsg,


@@ -323,6 +368,10 @@ func sendBanMessage(rwc io.Writer, message string) {
 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
        defer dontPanic(s.Logger)
 
 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
        defer dontPanic(s.Logger)
 

+       if err := performHandshake(rwc); err != nil {
+               return fmt.Errorf("perform handshake: %w", err)
+       }
+

        // Check if remoteAddr is present in the ban list
        ipAddr := strings.Split(remoteAddr, ":")[0]
        if isBanned, banUntil := s.BanList.IsBanned(ipAddr); isBanned {
        // Check if remoteAddr is present in the ban list
        ipAddr := strings.Split(remoteAddr, ":")[0]
        if isBanned, banUntil := s.BanList.IsBanned(ipAddr); isBanned {


@@ -341,10 +390,6 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
                }
        }
 
                }
        }
 

-       if err := performHandshake(rwc); err != nil {
-               return fmt.Errorf("error performing handshake: %w", err)
-       }
-

        // Create a new scanner for parsing incoming bytes into transaction tokens
        scanner := bufio.NewScanner(rwc)
        scanner.Split(transactionScanner)
        // Create a new scanner for parsing incoming bytes into transaction tokens
        scanner := bufio.NewScanner(rwc)
        scanner.Split(transactionScanner)


@@ -372,7 +417,7 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
                login = GuestAccount
        }
 
                login = GuestAccount
        }
 

-       c.logger = s.Logger.With("ip", ipAddr, "login", login)
+       c.Logger = s.Logger.With("ip", ipAddr, "login", login)

 
        // If authentication fails, send error reply and close connection
        if !c.Authenticate(login, encodedPassword) {
 
        // If authentication fails, send error reply and close connection
        if !c.Authenticate(login, encodedPassword) {


@@ -383,7 +428,7 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
                        return err
                }
 
                        return err
                }
 

-               c.logger.Info("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
+               c.Logger.Info("Incorrect login")

 
                return nil
        }
 
                return nil
        }


@@ -427,7 +472,10 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
                        c.Server.outbox <- NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
                }
        } else {
                        c.Server.outbox <- NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
                }
        } else {

-               c.Server.outbox <- NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement))
+               _, _ = c.Server.Agreement.Seek(0, 0)
+               data, _ := io.ReadAll(c.Server.Agreement)
+
+               c.Server.outbox <- NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, data))

        }
 
        // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login
        }
 
        // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login


@@ -435,8 +483,8 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
        if len(c.UserName) != 0 {
                // Add the client username to the logger.  For 1.5+ clients, we don't have this information yet as it comes as
                // part of TranAgreed
        if len(c.UserName) != 0 {
                // Add the client username to the logger.  For 1.5+ clients, we don't have this information yet as it comes as
                // part of TranAgreed

-               c.logger = c.logger.With("Name", string(c.UserName))
-               c.logger.Info("Login successful", "clientVersion", "Not sent (probably 1.2.3)")
+               c.Logger = c.Logger.With("name", string(c.UserName))
+               c.Logger.Info("Login successful")

 
                // Notify other clients on the server that the new user has logged in.  For 1.5+ clients we don't have this
                // information yet, so we do it in TranAgreed instead
 
                // Notify other clients on the server that the new user has logged in.  For 1.5+ clients we don't have this
                // information yet, so we do it in TranAgreed instead


@@ -463,11 +511,11 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
        // Scan for new transactions and handle them as they come in.
        for scanner.Scan() {
                // Copy the scanner bytes to a new slice to it to avoid a data race when the scanner re-uses the buffer.
        // Scan for new transactions and handle them as they come in.
        for scanner.Scan() {
                // Copy the scanner bytes to a new slice to it to avoid a data race when the scanner re-uses the buffer.

-               buf := make([]byte, len(scanner.Bytes()))
-               copy(buf, scanner.Bytes())
+               tmpBuf := make([]byte, len(scanner.Bytes()))
+               copy(tmpBuf, scanner.Bytes())

 
                var t Transaction
 
                var t Transaction

-               if _, err := t.Write(buf); err != nil {
+               if _, err := t.Write(tmpBuf); err != nil {

                        return err
                }
 
                        return err
                }
 


@@ -506,15 +554,15 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro
                "Name", string(fileTransfer.ClientConn.UserName),
        )
 
                "Name", string(fileTransfer.ClientConn.UserName),
        )
 

-       fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
+       fullPath, err := ReadPath(fileTransfer.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)

        if err != nil {
                return err
        }
 
        switch fileTransfer.Type {
        case BannerDownload:
        if err != nil {
                return err
        }
 
        switch fileTransfer.Type {
        case BannerDownload:

-               if _, err := io.Copy(rwc, bytes.NewBuffer(s.banner)); err != nil {
-                       return fmt.Errorf("error sending banner: %w", err)
+               if _, err := io.Copy(rwc, bytes.NewBuffer(s.Banner)); err != nil {
+                       return fmt.Errorf("banner download: %w", err)

                }
        case FileDownload:
                s.Stats.Increment(StatDownloadCounter, StatDownloadsInProgress)
                }
        case FileDownload:
                s.Stats.Increment(StatDownloadCounter, StatDownloadsInProgress)


@@ -535,7 +583,7 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro
 
                err = UploadHandler(rwc, fullPath, fileTransfer, s.FS, rLogger, s.Config.PreserveResourceForks)
                if err != nil {
 
                err = UploadHandler(rwc, fullPath, fileTransfer, s.FS, rLogger, s.Config.PreserveResourceForks)
                if err != nil {

-                       return fmt.Errorf("file upload error: %w", err)
+                       return fmt.Errorf("file upload: %w", err)

                }
 
        case FolderDownload:
                }
 
        case FolderDownload:


@@ -546,7 +594,7 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro
 
                err = DownloadFolderHandler(rwc, fullPath, fileTransfer, s.FS, rLogger, s.Config.PreserveResourceForks)
                if err != nil {
 
                err = DownloadFolderHandler(rwc, fullPath, fileTransfer, s.FS, rLogger, s.Config.PreserveResourceForks)
                if err != nil {

-                       return fmt.Errorf("file upload error: %w", err)
+                       return fmt.Errorf("folder download: %w", err)

                }
 
        case FolderUpload:
                }
 
        case FolderUpload:


@@ -564,8 +612,23 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro
 
                err = UploadFolderHandler(rwc, fullPath, fileTransfer, s.FS, rLogger, s.Config.PreserveResourceForks)
                if err != nil {
 
                err = UploadFolderHandler(rwc, fullPath, fileTransfer, s.FS, rLogger, s.Config.PreserveResourceForks)
                if err != nil {

-                       return fmt.Errorf("file upload error: %w", err)
+                       return fmt.Errorf("folder upload: %w", err)

                }
        }
        return nil
 }
                }
        }
        return nil
 }

+
+func (s *Server) SendAll(t TranType, fields ...Field) {
+       for _, c := range s.ClientMgr.List() {
+               s.outbox <- NewTransaction(t, c.ID, fields...)
+       }
+}
+
+func (s *Server) Shutdown(msg []byte) {
+       s.Logger.Info("Shutdown signal received")
+       s.SendAll(TranDisconnectMsg, NewField(FieldData, msg))
+
+       time.Sleep(3 * time.Second)
+
+       os.Exit(0)
+}