diff --git a/cmd/server/main.go b/cmd/server/main.go
new file mode 100644
index 0000000..c66fe75
--- /dev/null
+++ b/cmd/server/main.go
@@ -0,0 +1,32 @@
+/* diodemail - send-only smtp server
+ * Copyright (c) 2024 Gnarwhal
+ *
+ * This file is part of SSHare.
+ *
+ * SSHare 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.
+ *
+ * SSHare 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
+ * SSHare. If not, see .
+ */
+
+package main
+
+import (
+ "log"
+
+ "forge.monodon.me/Gnarwhal/diodemail/smtp"
+)
+
+func main() {
+ err := smtp.Run(":4650", false)
+ if err != nil {
+ log.Fatal(err)
+ }
+}
diff --git a/go.mod b/go.mod
index 55c51c9..6cdcd65 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,11 @@
module forge.monodon.me/Gnarwhal/diodemail
go 1.23.1
+
+require github.com/rs/zerolog v1.33.0
+
+require (
+ github.com/mattn/go-colorable v0.1.13 // indirect
+ github.com/mattn/go-isatty v0.0.19 // indirect
+ golang.org/x/sys v0.12.0 // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..98afda4
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,15 @@
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.19 h1:JITubQf0MOLdlGRuRq+jtsDlekdYPia9ZFsB8h/APPA=
+github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
+github.com/rs/zerolog v1.33.0 h1:1cU2KZkvPxNyfgEmhHAz/1A9Bz+llsdYzklWFzgp0r8=
+github.com/rs/zerolog v1.33.0/go.mod h1:/7mN4D5sKwJLZQ2b/znpjC3/GQWY/xaDXUM0kKWRHss=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
diff --git a/smtp/connection.go b/smtp/connection.go
new file mode 100644
index 0000000..a185b84
--- /dev/null
+++ b/smtp/connection.go
@@ -0,0 +1,57 @@
+/* diodemail - send-only smtp server
+ * Copyright (c) 2024 Gnarwhal
+ *
+ * This file is part of SSHare.
+ *
+ * SSHare 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.
+ *
+ * SSHare 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
+ * SSHare. If not, see .
+ */
+
+package smtp
+
+import (
+ "net"
+
+ "github.com/rs/zerolog/log"
+)
+
+type Connection struct {
+ connection net.Conn
+}
+
+func (self Connection) Read() (string, error) {
+ buffer := [64]byte{}
+ read, err := self.connection.Read(buffer[:])
+ if err != nil {
+ return "", err
+ }
+
+ message := string(buffer[:read - 2])
+
+ log.Trace().Msgf("%v -> %v", self.RemoteAddr(), message)
+
+ return message, nil
+}
+
+func (self Connection) Write(message string) error {
+ log.Trace().Msgf("%v <- %v", self.RemoteAddr(), message[:len(message) - 1])
+ _, err := self.connection.Write([]byte(message))
+ return err
+}
+
+func (self Connection) Close() {
+ self.connection.Close()
+}
+
+func (self Connection) RemoteAddr() net.Addr {
+ return self.connection.RemoteAddr()
+}
diff --git a/smtp/handlers.go b/smtp/handlers.go
new file mode 100644
index 0000000..e5ff087
--- /dev/null
+++ b/smtp/handlers.go
@@ -0,0 +1,103 @@
+/* diodemail - send-only smtp server
+ * Copyright (c) 2024 Gnarwhal
+ *
+ * This file is part of SSHare.
+ *
+ * SSHare 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.
+ *
+ * SSHare 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
+ * SSHare. If not, see .
+ */
+
+package smtp
+
+import (
+ "fmt"
+ "strings"
+)
+
+type Command struct {
+ name string
+ Exec func(Connection)([]Command, error)
+}
+
+func (self Command) Name() string {
+ return self.name
+}
+
+func (self Command) Check(message string) bool {
+ return strings.HasPrefix(message, self.name)
+}
+
+func (self Connection) Chain() error {
+ commands, err := Greet(self)
+ if err != nil {
+ return err
+ }
+ for {
+ message, err := self.Read()
+ if err != nil {
+ return err
+ }
+
+ command_found := false
+ for _, command := range commands {
+ if command.Check(message) {
+ commands, err = command.Exec(self)
+ if err != nil {
+ return err
+ }
+ command_found = true
+ break
+ }
+ }
+ if !command_found {
+ expected := make([]string, len(commands))
+ for index, command := range commands {
+ expected[index] = command.Name()
+ }
+ return fmt.Errorf("Expected one of %v, but got: %v", expected, message)
+ }
+
+ if len(commands) == 0 {
+ break
+ }
+ }
+ return nil
+}
+
+/* --- GREETING RESPONSE --- */
+
+func Greet(connection Connection) ([]Command, error) {
+ err := connection.Write(
+ "220 localhost ESMTP diodemail -- Service ready" + "\n",
+ )
+ if err != nil {
+ return nil, err
+ }
+
+ return []Command{
+ Command{ "HELO", Hello },
+ Command{ "EHLO", Hello },
+ }, nil
+}
+
+/* --- HELO/EHLO RESPONSE --- */
+
+func Hello(connection Connection) ([]Command, error) {
+ err := connection.Write(
+ fmt.Sprintf("250 %v is shy", connection.connection.LocalAddr()) + "\n",
+ )
+ if err != nil {
+ return nil, err
+ }
+
+ return []Command{}, nil
+}
diff --git a/smtp/server.go b/smtp/server.go
new file mode 100644
index 0000000..21b9fa1
--- /dev/null
+++ b/smtp/server.go
@@ -0,0 +1,69 @@
+/* diodemail - send-only smtp server
+ * Copyright (c) 2024 Gnarwhal
+ *
+ * This file is part of SSHare.
+ *
+ * SSHare 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.
+ *
+ * SSHare 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
+ * SSHare. If not, see .
+ */
+
+package smtp
+
+import (
+ "net"
+ "os"
+
+ "github.com/rs/zerolog"
+ "github.com/rs/zerolog/log"
+)
+
+type PlainListener struct {
+ listener net.Listener
+}
+
+func handle(connection Connection) {
+ log.Info().Msgf("New connection %v", connection.RemoteAddr())
+ defer connection.Close()
+ err := connection.Chain()
+ if err != nil {
+ log.Error().Msgf("Failed to serve %v: %v", connection.RemoteAddr(), err)
+ } else {
+ log.Info().Msgf("Successfully served %v", connection.RemoteAddr())
+ }
+}
+
+func Run(host string, implicit_tls bool) error {
+ log.Logger = zerolog.
+ New(zerolog.ConsoleWriter{Out: os.Stderr}).
+ With().
+ Timestamp().
+ Logger().
+ Level(zerolog.TraceLevel)
+
+ listener, err := net.Listen("tcp", host)
+ if err != nil {
+ return err
+ }
+
+ for {
+ connection, err := listener.Accept()
+ if err != nil {
+ return err
+ }
+
+ go handle(Connection{connection})
+ }
+}
+
+func (self PlainListener) Close() error {
+ return self.listener.Close()
+}