smtp.go

   1 package main
   2
   3 import (
   4         "crypto/tls"
   5         "fmt"
   6         "net"
   7         "net/mail"
   8         "os"
   9         "path"
  10         "strings"
  11
  12         "github.com/uber-go/zap"
  13
  14         "src.bluestatic.org/mailpopbox/smtp"
  15 )
  16
  17 func runSMTPServer(config Config, log zap.Logger) <-chan error {
  18         server := smtpServer{
  19                 config: config,
  20                 rc:     make(chan error),
  21                 log:    log.With(zap.String("server", "smtp")),
  22         }
  23         go server.run()
  24         return server.rc
  25 }
  26
  27 type smtpServer struct {
  28         config    Config
  29         tlsConfig *tls.Config
  30
  31         log zap.Logger
  32
  33         rc chan error
  34 }
  35
  36 func (server *smtpServer) run() {
  37         var err error
  38         server.tlsConfig, err = server.config.GetTLSConfig()
  39         if err != nil {
  40                 server.log.Error("failed to configure TLS", zap.Error(err))
  41                 server.rc <- err
  42         }
  43
  44         addr := fmt.Sprintf(":%d", server.config.SMTPPort)
  45         server.log.Info("starting server", zap.String("address", addr))
  46
  47         l, err := net.Listen("tcp", addr)
  48         if err != nil {
  49                 server.log.Error("listen", zap.Error(err))
  50                 server.rc <- err
  51                 return
  52         }
  53
  54         for {
  55                 conn, err := l.Accept()
  56                 if err != nil {
  57                         server.log.Error("accept", zap.Error(err))
  58                         server.rc <- err
  59                         return
  60                 }
  61
  62                 go smtp.AcceptConnection(conn, server, server.log)
  63         }
  64 }
  65
  66 func (server *smtpServer) Name() string {
  67         return server.config.Hostname
  68 }
  69
  70 func (server *smtpServer) TLSConfig() *tls.Config {
  71         return server.tlsConfig
  72 }
  73
  74 func (server *smtpServer) VerifyAddress(addr mail.Address) smtp.ReplyLine {
  75         if server.maildropForAddress(addr) == "" {
  76                 return smtp.ReplyBadMailbox
  77         }
  78         return smtp.ReplyOK
  79 }
  80
  81 func (server *smtpServer) OnEHLO() *smtp.ReplyLine {
  82         return nil
  83 }
  84
  85 func (server *smtpServer) OnMessageDelivered(en smtp.Envelope) *smtp.ReplyLine {
  86         maildrop := server.maildropForAddress(en.RcptTo[0])
  87         if maildrop == "" {
  88                 // TODO: log error
  89                 return &smtp.ReplyBadMailbox
  90         }
  91
  92         f, err := os.Create(path.Join(maildrop, en.ID+".msg"))
  93         if err != nil {
  94                 // TODO: log error
  95                 return &smtp.ReplyBadMailbox
  96         }
  97
  98         smtp.WriteEnvelopeForDelivery(f, en)
  99         f.Close()
 100         return nil
 101 }
 102
 103 func (server *smtpServer) maildropForAddress(addr mail.Address) string {
 104         domainIdx := strings.LastIndex(addr.Address, "@")
 105         if domainIdx == -1 {
 106                 return ""
 107         }
 108
 109         domain := addr.Address[domainIdx+1:]
 110
 111         for _, s := range server.config.Servers {
 112                 if domain == s.Domain {
 113                         return s.MaildropPath
 114                 }
 115         }
 116
 117         return ""
 118 }