func RunTCP(t TCPService) {
l, err := net.ListenTCP("tcp", t.Addr())
if err != nil {
log.Error("failed to bind to local address %s", t.Addr())
t.Shutdown()
return
}
defer l.Close()
log.Info("listening for connections on %s", t.Addr())
for {
conn, err := l.AcceptTCP()
if err != nil {
log.Error("failed to accept connection: %v", err)
continue
}
if err := t.SetClientOptions(conn); err != nil {
conn.Close()
continue
}
log.Trace(func() string {
return fmt.Sprintf("%s: client connected to %s", conn.RemoteAddr(), t.Addr())
})
go t.Handle(conn)
}
}
// Process an incoming admin service connection.
func (a *AdminService) Handle(conn *net.TCPConn) {
defer func() {
log.Trace(func() string {
return fmt.Sprintf("%s: client disconnected", conn.RemoteAddr())
})
conn.Close()
}()
if a.draining {
return
}
}
// Process an incoming SMTP connection.
func (s *SMTPService) Handle(conn *net.TCPConn) {
defer func() {
log.Trace(func() string {
return fmt.Sprintf("%s: client disconnected", conn.RemoteAddr())
})
conn.Close()
}()
// Send a 421 error response if the server is in the process of shutting
// down when the client connects.
if s.draining {
conn.Write(ResponseMap[421])
return
}
session := NewSMTPSession(conn, s.cfg)
if verdict := session.Greet(); verdict == Terminate {
return
}
for {
if verdict := session.Process(); verdict == Terminate {
return
}
}
}