We build too many walls and not enough bridges

2020-04-08 12:59:16 +02:00
commit 17f4d6097a
494 changed files with 62753 additions and 0 deletions
--- a/internal/smtp/server.go
+++ b/internal/smtp/server.go
@ -0,0 +1,112 @@
+// Copyright (c) 2020 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package smtp
+
+import (
+	"crypto/tls"
+	"fmt"
+
+	"github.com/ProtonMail/proton-bridge/internal/bridge"
+	"github.com/ProtonMail/proton-bridge/internal/events"
+	"github.com/ProtonMail/proton-bridge/pkg/listener"
+	"github.com/emersion/go-sasl"
+	goSMTP "github.com/emersion/go-smtp"
+	"github.com/sirupsen/logrus"
+)
+
+type smtpServer struct {
+	server        *goSMTP.Server
+	eventListener listener.Listener
+	useSSL        bool
+}
+
+// NewSMTPServer returns an SMTP server configured with the given options.
+func NewSMTPServer(debug bool, port int, useSSL bool, tls *tls.Config, smtpBackend goSMTP.Backend, eventListener listener.Listener) *smtpServer { //nolint[golint]
+	s := goSMTP.NewServer(smtpBackend)
+	s.Addr = fmt.Sprintf("%v:%v", bridge.Host, port)
+	s.TLSConfig = tls
+	s.Domain = bridge.Host
+	s.AllowInsecureAuth = true
+
+	if debug {
+		s.Debug = logrus.
+			WithField("pkg", "smtp/server").
+			WriterLevel(logrus.DebugLevel)
+	}
+
+	s.EnableAuth(sasl.Login, func(conn *goSMTP.Conn) sasl.Server {
+		return sasl.NewLoginServer(func(address, password string) error {
+			user, err := conn.Server().Backend.Login(address, password)
+			if err != nil {
+				return err
+			}
+
+			conn.SetUser(user)
+			return nil
+		})
+	})
+
+	return &smtpServer{
+		server:        s,
+		eventListener: eventListener,
+		useSSL:        useSSL,
+	}
+}
+
+// Starts the server.
+func (s *smtpServer) ListenAndServe() {
+	go s.monitorDisconnectedUsers()
+	l := log.WithField("useSSL", s.useSSL).WithField("address", s.server.Addr)
+
+	l.Info("SMTP server is starting")
+	var err error
+	if s.useSSL {
+		err = s.server.ListenAndServeTLS()
+	} else {
+		err = s.server.ListenAndServe()
+	}
+	if err != nil {
+		s.eventListener.Emit(events.ErrorEvent, "SMTP failed: "+err.Error())
+		l.Error("SMTP failed: ", err)
+		return
+	}
+	defer s.server.Close()
+
+	l.Info("SMTP server stopped")
+}
+
+// Stops the server.
+func (s *smtpServer) Close() {
+	s.server.Close()
+}
+
+func (s *smtpServer) monitorDisconnectedUsers() {
+	ch := make(chan string)
+	s.eventListener.Add(events.CloseConnectionEvent, ch)
+
+	for address := range ch {
+		log.Info("Disconnecting all open SMTP connections for ", address)
+		disconnectUser := func(conn *goSMTP.Conn) {
+			connUser := conn.User()
+			if connUser != nil {
+				_ = conn.Close()
+			}
+		}
+		s.server.ForEachConn(disconnectUser)
+	}
+}