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-rw-r--r--config.go10
-rw-r--r--main.go2
-rw-r--r--mta_recv.go98
3 files changed, 65 insertions, 45 deletions
diff --git a/config.go b/config.go
index c76fa94..6605262 100644
--- a/config.go
+++ b/config.go
@@ -2,6 +2,7 @@ package main
import (
"bufio"
+ "crypto/tls"
"os"
"sync"
@@ -15,6 +16,7 @@ var config struct {
Cert string `scfg:"cert"`
Key string `scfg:"key"`
} `scfg:"tls"`
+ _tls_config *tls.Config
}
var config_mutex sync.RWMutex
@@ -31,6 +33,14 @@ func load_config(path string) error {
if err != nil {
return err
}
+ cer, err := tls.LoadX509KeyPair(config.TLS.Cert, config.TLS.Key)
+ if err != nil {
+ return err
+ }
+ config._tls_config = &tls.Config{
+ Certificates: []tls.Certificate{cer},
+ MinVersion: tls.VersionTLS13,
+ }
return nil
}() != nil {
return err
diff --git a/main.go b/main.go
index c2ee302..91ca98f 100644
--- a/main.go
+++ b/main.go
@@ -32,7 +32,7 @@ func main() {
}
go func() {
- err := handle_incoming_server_connection(bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn)))
+ err := handle_incoming_server_connection(bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn)), &conn)
if err != nil && !errors.Is(err, io.EOF) {
clog.Error("connection handler returned error", "err", err)
}
diff --git a/mta_recv.go b/mta_recv.go
index 1f680fa..3f7f473 100644
--- a/mta_recv.go
+++ b/mta_recv.go
@@ -3,6 +3,8 @@ package main
import (
"bufio"
"bytes"
+ "crypto/tls"
+ "net"
"slices"
"strings"
@@ -18,21 +20,24 @@ const (
server_state_rcpt
)
-func handle_incoming_server_connection(conn *bufio.ReadWriter) error {
+func handle_incoming_server_connection(buf_conn *bufio.ReadWriter, net_conn *net.Conn) error {
+ var tls_conn *tls.Conn
var my_server_name string
var routes map[string]string
+ var tls_config *tls.Config
config_consistent_run(func() {
my_server_name = config.Server_name
routes = config.Routes
+ tls_config = config._tls_config
})
- _, _ = conn.WriteString("220 " + my_server_name + " " + VERSION + "\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("220 " + my_server_name + " " + VERSION + "\r\n")
+ _ = buf_conn.Flush()
server_state := server_state_begin
var remote_server_name string
var current_mail_from string
var current_rcpt_to []string
for {
- line, err := conn.ReadString('\n')
+ line, err := buf_conn.ReadString('\n')
if err != nil {
return err
}
@@ -50,79 +55,84 @@ func handle_incoming_server_connection(conn *bufio.ReadWriter) error {
param := line[param_start:]
switch_cmd:
switch cmd {
+ case "STARTTLS":
+ _, _ = buf_conn.WriteString("220 2.0.0 Ready to start TLS\r\n")
+ _ = buf_conn.Flush()
+ tls_conn = tls.Server(*net_conn, tls_config)
+ buf_conn = bufio.NewReadWriter(bufio.NewReader(tls_conn), bufio.NewWriter(tls_conn))
case "HELO":
if param == "" { // TODO: actually validate the hostname
- _, _ = conn.WriteString("501 Syntax: HELO hostname\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("501 Syntax: HELO hostname\r\n")
+ _ = buf_conn.Flush()
break
}
remote_server_name = param
_ = remote_server_name // TODO
server_state = server_state_helo
- _, _ = conn.WriteString("250 " + my_server_name + "\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("250 " + my_server_name + "\r\n")
+ _ = buf_conn.Flush()
case "MAIL":
switch server_state {
case server_state_begin:
- _, _ = conn.WriteString("503 5.5.1 Error: send HELO/EHLO first\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("503 5.5.1 Error: send HELO/EHLO first\r\n")
+ _ = buf_conn.Flush()
break switch_cmd
case server_state_helo:
break
case server_state_mail:
- _, _ = conn.WriteString("503 5.5.1 Error: nested MAIL command\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("503 5.5.1 Error: nested MAIL command\r\n")
+ _ = buf_conn.Flush()
break switch_cmd
}
if len(param) <= len("FROM:") || strings.ToUpper(param[:len("FROM:")]) != "FROM:" {
- _, _ = conn.WriteString("501 5.5.4 Syntax: MAIL FROM:<address>\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("501 5.5.4 Syntax: MAIL FROM:<address>\r\n")
+ _ = buf_conn.Flush()
break
}
current_mail_from = param[len("FROM:"):]
current_rcpt_to = []string{}
server_state = server_state_mail
- _, _ = conn.WriteString("250 2.1.0 Ok\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("250 2.1.0 Ok\r\n")
+ _ = buf_conn.Flush()
// TODO: Address validation
case "RCPT":
if server_state != server_state_mail && server_state != server_state_rcpt {
- _, _ = conn.WriteString("503 5.5.1 Error: need MAIL command\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("503 5.5.1 Error: need MAIL command\r\n")
+ _ = buf_conn.Flush()
break
}
if len(param) <= len("TO:") || strings.ToUpper(param[:len("TO:")]) != "TO:" {
- _, _ = conn.WriteString("501 5.5.4 Syntax: RCPT TO:<address>\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("501 5.5.4 Syntax: RCPT TO:<address>\r\n")
+ _ = buf_conn.Flush()
break
}
recipient, _, _ := mailkit.Strip_angle_brackets(param[len("TO:"):])
_, ok := routes[recipient]
if !ok {
- _, _ = conn.WriteString("550 5.1.1 <" + recipient + ">: Recipient address rejected: User unknown in local recipient table\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("550 5.1.1 <" + recipient + ">: Recipient address rejected: User unknown in local recipient table\r\n")
+ _ = buf_conn.Flush()
break switch_cmd
}
current_rcpt_to = append(current_rcpt_to, recipient)
server_state = server_state_rcpt
- _, _ = conn.WriteString("250 2.1.5 Ok\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("250 2.1.5 Ok\r\n")
+ _ = buf_conn.Flush()
case "DATA":
if server_state != server_state_rcpt {
- _, _ = conn.WriteString("503 5.5.1 Error: need RCPT command\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("503 5.5.1 Error: need RCPT command\r\n")
+ _ = buf_conn.Flush()
break
}
- _, _ = conn.WriteString("354 End data with <CR><LF>.<CR><LF>\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("354 End data with <CR><LF>.<CR><LF>\r\n")
+ _ = buf_conn.Flush()
var current_data []byte
for {
- tmp, err := conn.ReadSlice('\r')
+ tmp, err := buf_conn.ReadSlice('\r')
if err != nil {
return err
}
- // conn.ReadSlice returns an internal buffer that gets
+ // buf_conn.ReadSlice returns an internal buffer that gets
// overwritten on the next reader operation. So we must
// make a copy; also we have to allocate data_part to
// the correct length because [[builtin.copy]] copies
@@ -130,7 +140,7 @@ func handle_incoming_server_connection(conn *bufio.ReadWriter) error {
data_part := make([]byte, len(tmp))
copy(data_part, tmp)
- next_four, err := conn.Peek(4)
+ next_four, err := buf_conn.Peek(4)
if err != nil {
return err
}
@@ -140,7 +150,7 @@ func handle_incoming_server_connection(conn *bufio.ReadWriter) error {
}
current_data = slices.Concat(current_data, data_part)
}
- _, err := conn.Discard(4)
+ _, err := buf_conn.Discard(4)
if err != nil {
return err
}
@@ -149,7 +159,7 @@ func handle_incoming_server_connection(conn *bufio.ReadWriter) error {
for _, recipient := range current_rcpt_to {
inbox, ok := routes[recipient]
if !ok {
- _, _ = conn.WriteString("550 5.1.1 <" + recipient + ">: Recipient address rejected: User unknown in local recipient table\r\n")
+ _, _ = buf_conn.WriteString("550 5.1.1 <" + recipient + ">: Recipient address rejected: User unknown in local recipient table\r\n")
break switch_cmd
}
inboxes_to_deliver_to[inbox] = struct{}{}
@@ -159,28 +169,28 @@ func handle_incoming_server_connection(conn *bufio.ReadWriter) error {
}
}
if err == nil {
- _, _ = conn.WriteString("250 2.0.0 Ok: Accepted\r\n")
+ _, _ = buf_conn.WriteString("250 2.0.0 Ok: Accepted\r\n")
} else {
- _, _ = conn.WriteString("500 2.0.0 Error: " + err.Error() + "\r\n")
+ _, _ = buf_conn.WriteString("500 2.0.0 Error: " + err.Error() + "\r\n")
}
- _ = conn.Flush()
+ _ = buf_conn.Flush()
server_state = server_state_helo
case "QUIT":
- _, _ = conn.WriteString("221 2.0.0 Bye\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("221 2.0.0 Bye\r\n")
+ _ = buf_conn.Flush()
return nil
case "NOOP":
- _, _ = conn.WriteString("250 2.0.0 Ok\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("250 2.0.0 Ok\r\n")
+ _ = buf_conn.Flush()
case "RSET":
if server_state != server_state_begin {
server_state = server_state_helo
}
- _, _ = conn.WriteString("250 2.0.0 Ok\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("250 2.0.0 Ok\r\n")
+ _ = buf_conn.Flush()
default:
- _, _ = conn.WriteString("500 5.5.2 Error: command not recognized\r\n")
- _ = conn.Flush()
+ _, _ = buf_conn.WriteString("500 5.5.2 Error: command not recognized\r\n")
+ _ = buf_conn.Flush()
}
}
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-01-18 18:22:57 +0000