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This commit is contained in:
Gnarwhal 2024-09-29 21:51:03 +00:00
parent a66b846fb3
commit 49568598ed
Signed by: Gnarwhal
GPG key ID: 0989A73D8C421174
4 changed files with 263 additions and 257 deletions

168
smtp/commands.go Normal file
View file

@ -0,0 +1,168 @@
/* 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 <https://www.gnu.org/licenses/>.
*/
package smtp
import (
"fmt"
"strings"
)
type Command struct {
name string
Exec func(SMTPSession, string)(bool, error)
}
func (self Command) Name() string {
return self.name
}
func (self Command) Check(message string) bool {
return strings.HasPrefix(message, self.name)
}
func Greet(smtp_session SMTPSession) error {
err := smtp_session.Write(
"220 localhost ESMTPSession diodemail -- Service ready" + "\n",
)
if err != nil {
return err
}
return nil
}
func Helo(smtp_session SMTPSession, message string) (bool, error) {
err := smtp_session.Write(
fmt.Sprintf(
"250 %v is shy" + "\r\n",
smtp_session.GetAddress(),
),
)
if err != nil {
return false, err
}
return false, nil
}
func Ehlo(smtp_session SMTPSession, message string) (bool, error) {
err := smtp_session.Write(
fmt.Sprintf(
"250 %v is shy" + "\r\n",
smtp_session.GetAddress(),
),
)
if err != nil {
return false, err
}
return false, nil
}
func MailFrom(smtp_session SMTPSession, message string) (bool, error) {
match := ReversePath.FindStringSubmatch(message)
if match == nil {
smtp_session.Write(
"501 Could not parse reverse-path",
)
} else if len(match) > 1 {
smtp_session.MailFrom(match[1])
err := smtp_session.Write(
"250 OK\n",
)
if err != nil {
return false, err
}
}
return false, nil
}
func RcptTo(smtp_session SMTPSession, message string) (bool, error) {
match := ForwardPath.FindStringSubmatch(message)
if match == nil {
smtp_session.Write(
"501 Could not parse forward-path",
)
} else {
smtp_session.AddRecipient(match[1])
err := smtp_session.Write(
"250 OK\n",
)
if err != nil {
return false, err
}
}
return false, nil
}
func Data(smtp_session SMTPSession, message string) (bool, error) {
err := smtp_session.Write(
"354 Start Input\n",
)
if err != nil {
return false, err
}
data, err := smtp_session.Read("\r\n.\r\n")
smtp_session.SetMailBuffer(data)
err = smtp_session.Write(
"250 OK\n",
)
smtp_session.Reset()
if err != nil {
return false, err
}
return false, nil
}
func Quit(smtp_session SMTPSession, message string) (bool, error) {
err := smtp_session.Write(
"221 Goodbye :)\n",
)
if err != nil {
return true, err
}
return true, nil
}
func Noop(smtp_session SMTPSession, message string) (bool, error) {
err := smtp_session.Write(
"250 OK\n",
)
if err != nil {
return false, err
}
return false, nil
}
func Rset(smtp_session SMTPSession, message string) (bool, error) {
err := smtp_session.Write(
"250 Reset\n",
)
smtp_session.Reset()
if err != nil {
return false, err
}
return false, nil
}

View file

@ -20,13 +20,13 @@ package smtp
import (
"net"
// "fmt"
"fmt"
"strings"
"github.com/rs/zerolog/log"
)
type Connection struct {
type SMTPSession struct {
connection net.Conn
ReversePathBuffer *string
@ -34,8 +34,8 @@ type Connection struct {
MailBuffer *string
}
func NewConnection(connection net.Conn) Connection {
return Connection{
func MakeSMTPSession(connection net.Conn) SMTPSession {
return SMTPSession{
connection,
nil,
[]string{},
@ -43,8 +43,62 @@ func NewConnection(connection net.Conn) Connection {
}
}
func (self SMTPSession) Run() error {
err := Greet(self)
if err != nil {
return err
}
COMMANDS := []Command{
Command{ "HELO", Helo },
Command{ "EHLO", Ehlo },
Command{ "MAIL FROM:", MailFrom },
Command{ "RCPT TO:", RcptTo },
Command{ "DATA", Data },
Command{ "QUIT", Quit },
Command{ "NOOP", Noop },
Command{ "RSET", Rset },
}
quit := false
for !quit {
message, err := self.Read("\n")
if err != nil {
return err
}
command_found := false
for _, command := range COMMANDS {
if command.Check(message) {
command_found = true
quit, err = command.Exec(self, message[len(command.Name()):])
if err != nil {
return err
}
break
}
}
if !command_found {
self.Write("500 Unrecognized Command\n")
}
}
return nil
}
func (self SMTPSession) TraceSession(direction string, message string) {
lines := strings.Split(message, "\n")
for index, line := range lines {
if index != len(lines) - 1 || line != "" {
if index == 0 {
log.Trace().Msgf("%v %v %v", self.connection.RemoteAddr(), direction, line)
} else {
log.Trace().Msgf("%v %v", self.connection.RemoteAddr(), line)
}
}
}
}
var buffer = [1024]byte{}
func (self Connection) Read(delimiter string) (string, error) {
func (self SMTPSession) Read(delimiter string) (string, error) {
var message string
for !strings.Contains(message, delimiter) {
num_read, err := self.connection.Read(buffer[:])
@ -53,50 +107,36 @@ func (self Connection) Read(delimiter string) (string, error) {
}
message += string(buffer[:num_read])
}
lines := strings.Split(message, "\n")
for index, line := range lines {
if index != len(lines) - 1 || line != "" {
if index == 0 {
log.Trace().Msgf("%v -> %v", self.RemoteAddr(), line)
} else {
log.Trace().Msgf("%v %v", self.RemoteAddr(), line)
}
}
}
self.TraceSession(" ->", message)
return message[:len(message) - len(delimiter)], nil
}
func (self Connection) Write(message string) error {
lines := strings.Split(message, "\n")
for index, line := range lines {
if index != len(lines) - 1 || line != "" {
if index == 0 {
log.Trace().Msgf("%v <- %v", self.RemoteAddr(), line)
} else {
log.Trace().Msgf("%v %v", self.RemoteAddr(), line)
}
}
}
func (self SMTPSession) Write(message string) error {
self.TraceSession("<- ", message)
_, err := self.connection.Write([]byte(message))
return err
}
func (self Connection) AddRecipient(recipient string) {
func (self SMTPSession) GetAddress() string {
return fmt.Sprint(self.connection.LocalAddr())
}
func (self SMTPSession) MailFrom(from string) {
self.Reset()
self.ReversePathBuffer = &from
}
func (self SMTPSession) AddRecipient(recipient string) {
self.ForwardPathBuffer = append(self.ForwardPathBuffer, recipient)
}
func (self Connection) Reset() {
func (self SMTPSession) SetMailBuffer(data string) {
self.MailBuffer = &data
}
func (self SMTPSession) Reset() {
self.ReversePathBuffer = nil
self.ForwardPathBuffer = []string{}
self.MailBuffer = nil
}
func (self Connection) Close() {
self.connection.Close()
}
func (self Connection) RemoteAddr() net.Addr {
return self.connection.RemoteAddr()
}

View file

@ -1,214 +0,0 @@
/* 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 <https://www.gnu.org/licenses/>.
*/
package smtp
import (
"fmt"
"strings"
)
type Command struct {
name string
Exec func(Connection, string)(bool, 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 {
err := Greet(self)
if err != nil {
return err
}
COMMANDS := []Command{
Command{ "HELO", Helo },
Command{ "EHLO", Ehlo },
Command{ "MAIL FROM:", MailFrom },
Command{ "RCPT TO:", RcptTo },
Command{ "DATA", Data },
Command{ "QUIT", Quit },
Command{ "NOOP", Noop },
Command{ "RSET", Rset },
}
quit := false
for !quit {
message, err := self.Read("\n")
if err != nil {
return err
}
command_found := false
for _, command := range COMMANDS {
if command.Check(message) {
command_found = true
quit, err = command.Exec(self, message[len(command.Name()):])
if err != nil {
return err
}
break
}
}
if !command_found {
self.Write("500 Unrecognized Command\n")
}
}
return nil
}
/* --- GREETING RESPONSE --- */
func Greet(connection Connection) error {
err := connection.Write(
"220 localhost ESMTP diodemail -- Service ready" + "\n",
)
if err != nil {
return err
}
return nil
}
/* --- HELO/EHLO RESPONSE --- */
func Helo(connection Connection, message string) (bool, error) {
err := connection.Write(
fmt.Sprintf(
"250 %v is shy" + "\r\n",
connection.connection.LocalAddr(),
),
)
if err != nil {
return false, err
}
return false, nil
}
func Ehlo(connection Connection, message string) (bool, error) {
err := connection.Write(
fmt.Sprintf(
"250 %v is shy" + "\r\n",
connection.connection.LocalAddr(),
),
)
if err != nil {
return false, err
}
return false, nil
}
/* --- MAIL FROM RESPONSE --- */
func MailFrom(connection Connection, message string) (bool, error) {
match := ReversePath.FindStringSubmatch(message)
if match == nil {
connection.Write(
"501 Could not parse reverse-path",
)
} else if len(match) > 1 {
connection.ReversePathBuffer = &match[1]
err := connection.Write(
"250 OK\n",
)
if err != nil {
return false, err
}
}
return false, nil
}
func RcptTo(connection Connection, message string) (bool, error) {
match := ForwardPath.FindStringSubmatch(message)
if match == nil {
connection.Write(
"501 Could not parse forward-path",
)
} else {
connection.AddRecipient(match[1])
err := connection.Write(
"250 OK\n",
)
if err != nil {
return false, err
}
}
return false, nil
}
func Data(connection Connection, message string) (bool, error) {
err := connection.Write(
"354 Start Input\n",
)
if err != nil {
return false, err
}
data, err := connection.Read("\r\n.\r\n")
connection.MailBuffer = &data
err = connection.Write(
"250 OK\n",
)
connection.Reset()
if err != nil {
return false, err
}
return false, nil
}
func Quit(connection Connection, message string) (bool, error) {
err := connection.Write(
"221 Goodbye :)\n",
)
if err != nil {
return true, err
}
return true, nil
}
func Noop(connection Connection, message string) (bool, error) {
err := connection.Write(
"250 OK\n",
)
if err != nil {
return false, err
}
return false, nil
}
func Rset(connection Connection, message string) (bool, error) {
err := connection.Write(
"250 Reset\n",
)
connection.Reset()
if err != nil {
return false, err
}
return false, nil
}

View file

@ -30,14 +30,26 @@ type PlainListener struct {
listener net.Listener
}
func handle(connection Connection) {
log.Info().Msgf("New connection %v", connection.RemoteAddr())
func handle(connection net.Conn) {
log.Info().Msgf(
"New connection %v. Starting session.",
connection.RemoteAddr(),
)
defer connection.Close()
err := connection.Chain()
session := MakeSMTPSession(connection)
err := session.Run()
if err != nil {
log.Error().Msgf("Failed to serve %v: %v", connection.RemoteAddr(), err)
log.Error().Msgf(
"Session %v exited with error: %v",
connection.RemoteAddr(),
err,
)
} else {
log.Info().Msgf("Successfully served %v", connection.RemoteAddr())
log.Info().Msgf(
"Session %v exited successfully",
connection.RemoteAddr(),
)
}
}
@ -60,7 +72,7 @@ func Run(host string, implicit_tls bool) error {
return err
}
go handle(NewConnection(connection))
go handle(connection)
}
}