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Signed-off-by: Barry Simons <linuxuser586@gmail.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,89 @@ | ||
| // Copyright 2024 The OpenMail Authors | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
|
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| package main | ||
|
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| import ( | ||
| "log" | ||
| "os" | ||
|
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| "go.opentelemetry.io/otel" | ||
| "go.opentelemetry.io/otel/metric" | ||
| "go.opentelemetry.io/otel/trace" | ||
|
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| "github.com/linuxuser586/openmail/logger" | ||
| "github.com/linuxuser586/openmail/loggerzap" | ||
| "github.com/linuxuser586/openmail/smtpd" | ||
| ) | ||
|
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| const ( | ||
| defaultTimeout = 5 * 60 | ||
| name = "smtpd" | ||
| ) | ||
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| func main() { | ||
| s := smtpd.New(conf{}, tel{}, repo{}) | ||
| if err := s.ListenAndServe(); err != nil { | ||
| log.Fatal(err) | ||
| os.Exit(1) | ||
| } | ||
| } | ||
|
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| // TODO create configuration | ||
| type conf struct{} | ||
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| func (conf) Network() smtpd.Network { | ||
| return smtpd.Tcp | ||
| } | ||
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| func (conf) Host() string { | ||
| return "localhost" | ||
| } | ||
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| func (conf) Port() int { | ||
| return 2525 | ||
| } | ||
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| func (conf) InitialTimeout() int { | ||
| return defaultTimeout | ||
| } | ||
|
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| func (conf) MailCmdTimeout() int { | ||
| return defaultTimeout | ||
| } | ||
|
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| func (conf) RecipientCmdTimeout() int { | ||
| return defaultTimeout | ||
| } | ||
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| func (conf) DataInitTimeout() int { | ||
| return defaultTimeout | ||
| } | ||
|
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| func (conf) DataBlockTimeout() int { | ||
| return defaultTimeout | ||
| } | ||
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| func (conf) DataTerminationTimeout() int { | ||
| return defaultTimeout | ||
| } | ||
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| func (conf) HostName() string { | ||
| return "smtp.example.com" | ||
| } | ||
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| type tel struct{} | ||
|
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| func (tel) Tracer() trace.Tracer { | ||
| return otel.Tracer(name) | ||
| } | ||
|
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| func (tel) Meter() metric.Meter { | ||
| return otel.Meter(name) | ||
| } | ||
|
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| func (tel) Logger() logger.Logger { | ||
| return loggerzap.New(loggerzap.NewDevConfig()) | ||
| } | ||
|
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| type repo struct{} |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,228 @@ | ||
| // Copyright 2024 The OpenMail Authors | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
|
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| package smtpd | ||
|
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| import ( | ||
| "errors" | ||
| "fmt" | ||
| "net" | ||
| "net/textproto" | ||
| "strings" | ||
| "time" | ||
|
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| "github.com/linuxuser586/openmail/telemetry" | ||
| ) | ||
|
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| var ErrUnknownCommand = errors.New("unknown command") | ||
|
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| // Network listener enum | ||
| type Network string | ||
|
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| const ( | ||
| Tcp Network = "tcp" | ||
| Tcp4 Network = "tcp4" | ||
| Tcp6 Network = "tcp6" | ||
| Unix Network = "unix" | ||
| Unixpacket Network = "unixpacket" | ||
| ) | ||
|
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| // Command enum | ||
| type Command string | ||
|
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| const ( | ||
| Unknown Command = "" | ||
| ExtendedHello Command = "EHLO" | ||
| Hello Command = "HELO" | ||
| Mail Command = "MAIL" | ||
| Recipient Command = "RCPT" | ||
| Data Command = "DATA" | ||
| Reset Command = "RSET" | ||
| NoOperation Command = "NOOP" | ||
| Quit Command = "QUIT" | ||
| Verify Command = "VRFY" | ||
| ) | ||
|
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| func (c Command) String() string { | ||
| return string(c) | ||
| } | ||
|
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| // ToCommand converts a string to a command enum | ||
| func ToCommand(s string) (Command, error) { | ||
| // TODO finish implementation | ||
| switch strings.ToUpper(s) { | ||
| case ExtendedHello.String(): | ||
| return ExtendedHello, nil | ||
| case Quit.String(): | ||
| return Quit, nil | ||
| default: | ||
| return Unknown, ErrUnknownCommand | ||
| } | ||
| } | ||
|
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| // Config contains read only configurations for smtpd | ||
| type Config interface { | ||
| // Network type | ||
| Network() Network | ||
| // Host to listen on | ||
| Host() string | ||
| // Port to listen on | ||
| Port() int | ||
| // InitialTimeout in seconds | ||
| InitialTimeout() int | ||
| // MailCmdTimeout in seconds | ||
| MailCmdTimeout() int | ||
| // RecipientCmdTimeout in seconds | ||
| RecipientCmdTimeout() int | ||
| // DataInitTimeout in seconds | ||
| DataInitTimeout() int | ||
| // DataBlockTimeout in seconds | ||
| DataBlockTimeout() int | ||
| // DataTerminationTimeout in seconds | ||
| DataTerminationTimeout() int | ||
| // HostName for this instance | ||
| HostName() string | ||
| } | ||
|
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| // Repository manages persistence | ||
| type Repository interface { | ||
| } | ||
|
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| // TextConnection works with [net/textproto] | ||
| type TextConnection struct { | ||
| conn net.Conn | ||
| } | ||
|
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| func (t *TextConnection) Read(p []byte) (n int, err error) { | ||
| return t.conn.Read(p) | ||
| } | ||
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| func (t *TextConnection) Write(p []byte) (n int, err error) { | ||
| return t.conn.Write(p) | ||
| } | ||
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| func (t *TextConnection) Close() error { | ||
| return t.conn.Close() | ||
| } | ||
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| type Smtpd struct { | ||
| config Config | ||
| telemetry telemetry.Telemetry | ||
| repository Repository | ||
| } | ||
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| func New(config Config, telemetry telemetry.Telemetry, repository Repository) Smtpd { | ||
| return Smtpd{config: config, telemetry: telemetry, repository: repository} | ||
| } | ||
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| func (s *Smtpd) ListenAndServe() error { | ||
| log := s.telemetry.Logger() | ||
| listen, err := net.Listen(string(s.config.Network()), fmt.Sprintf("%s:%d", s.config.Host(), s.config.Port())) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| defer listen.Close() | ||
| log.Infof("smtpd started on %s", listen.Addr().String()) | ||
|
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| return s.serve(listen) | ||
| } | ||
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| func (s *Smtpd) serve(listen net.Listener) error { | ||
| for { | ||
| conn, err := listen.Accept() | ||
| if err != nil { | ||
| return err | ||
| } | ||
| config := s.config | ||
| telemetry := s.telemetry | ||
| repository := s.repository | ||
| go handleConn(config, telemetry, repository, conn) | ||
| } | ||
| } | ||
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| func handleConn( | ||
| config Config, | ||
| telemetry telemetry.Telemetry, | ||
| repository Repository, | ||
| conn net.Conn) { | ||
| textConn := TextConnection{conn: conn} | ||
| h := handler{ | ||
| config: config, | ||
| telemetry: telemetry, | ||
| repository: repository, | ||
| textConn: textConn, | ||
| protoConn: textproto.NewConn(&textConn), | ||
| } | ||
| h.handleConn() | ||
| } | ||
|
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| type handler struct { | ||
| config Config | ||
| telemetry telemetry.Telemetry | ||
| repository Repository | ||
| textConn TextConnection | ||
| protoConn *textproto.Conn | ||
| } | ||
|
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| func (h *handler) handleConn() { | ||
| tp := textproto.NewConn(&h.textConn) | ||
| conn := h.textConn.conn | ||
| log := h.telemetry.Logger() | ||
| log.Infof("request client address %s", conn.RemoteAddr().String()) | ||
| tp.PrintfLine(fmt.Sprintf("220 %s ESMTP OpenMail", h.config.HostName())) | ||
| conn.SetDeadline(time.Now().Add(time.Duration(h.config.InitialTimeout()) * time.Second)) | ||
| for { | ||
| line, err := tp.ReadLine() | ||
| if err != nil { | ||
| if h.handleReadTimeout(err, tp) { | ||
| return | ||
| } | ||
| log.Error(err.Error()) | ||
| // TODO respond to client with appropriate error message | ||
| continue | ||
| } | ||
|
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| log.Debug(line) | ||
|
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| cmd, err := ToCommand(line) | ||
| if err != nil { | ||
| tp.PrintfLine("500 5.5.2 Error: command not recognized") | ||
| continue | ||
| } | ||
| if err = h.handleCommand(cmd); err != nil { | ||
| // TODO use custom error | ||
| tp.PrintfLine(err.Error()) | ||
| } | ||
| } | ||
| } | ||
|
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| func (h handler) handleReadTimeout(err error, tp *textproto.Conn) bool { | ||
| if netErr := err.(*net.OpError); netErr != nil { | ||
| if netErr.Timeout() { | ||
| conn := h.textConn.conn | ||
| // reset the deadline so that the message can be sent to the client | ||
| conn.SetDeadline(time.Now().Add(5 * time.Second)) | ||
| tp.PrintfLine("421 connection timeout") | ||
| if err := h.textConn.Close(); err != nil { | ||
| h.telemetry.Logger().Error(err.Error()) | ||
| } | ||
| return true | ||
| } | ||
| } | ||
| return false | ||
| } | ||
|
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| func (h handler) handleCommand(cmd Command) error { | ||
| log := h.telemetry.Logger() | ||
| switch cmd { | ||
| case Quit: | ||
| if err := h.textConn.Close(); err != nil { | ||
| log.Error(err.Error()) | ||
| } | ||
| return nil | ||
| default: | ||
| log.Infof("TODO: %s not implemented", cmd.String()) | ||
| } | ||
|
|
||
| return nil | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,18 @@ | ||
| // Copyright 2024 The OpenMail Authors | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
|
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| // package telemetry provides traces, metrics, and logs | ||
| package telemetry | ||
|
|
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| import ( | ||
| "go.opentelemetry.io/otel/metric" | ||
| "go.opentelemetry.io/otel/trace" | ||
|
|
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| "github.com/linuxuser586/openmail/logger" | ||
| ) | ||
|
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| type Telemetry interface { | ||
| Tracer() trace.Tracer | ||
| Meter() metric.Meter | ||
| Logger() logger.Logger | ||
| } |