13 "github.com/uber-go/zap"
19 stateNew state
= iota // Before EHLO.
26 type connection
struct {
43 mailFrom
*mail
.Address
47 func AcceptConnection(netConn net
.Conn
, server Server
, log zap
.Logger
) {
50 tp
: textproto
.NewConn(netConn
),
52 remoteAddr
: netConn
.RemoteAddr(),
53 log
: log
.With(zap
.Stringer("client", netConn
.RemoteAddr())),
57 conn
.writeReply(220, fmt
.Sprintf("%s ESMTP [%s] (mailpopbox)", server
.Name(), netConn
.LocalAddr()))
61 conn
.line
, err
= conn
.tp
.ReadLine()
63 conn
.log
.Error("ReadLine()", zap
.Error(err
))
68 conn
.log
.Info("ReadLine()", zap
.String("line", conn
.line
))
71 if _
, err
= fmt
.Sscanf(conn
.line
, "%s", &cmd
); err
!= nil {
72 conn
.reply(ReplyBadSyntax
)
76 switch strings
.ToUpper(cmd
) {
78 conn
.writeReply(221, "Goodbye")
98 conn
.writeReply(252, "I'll do my best")
100 conn
.writeReply(550, "access denied")
104 conn
.writeReply(250, "https://tools.ietf.org/html/rfc5321")
106 conn
.writeReply(500, "unrecognized command")
111 func (conn
*connection
) reply(reply ReplyLine
) error
{
112 return conn
.writeReply(reply
.Code
, reply
.Message
)
115 func (conn
*connection
) writeReply(code
int, msg
string) error
{
116 conn
.log
.Info("writeReply", zap
.Int("code", code
))
119 err
= conn
.tp
.PrintfLine("%d %s", code
, msg
)
121 err
= conn
.tp
.PrintfLine("%d", code
)
124 conn
.log
.Error("writeReply",
125 zap
.Int("code", code
),
131 // parsePath parses out either a forward-, reverse-, or return-path from the
132 // current connection line. Returns a (valid-path, ReplyOK) if it was
133 // successfully parsed.
134 func (conn
*connection
) parsePath(command
string) (string, ReplyLine
) {
135 if len(conn
.line
) < len(command
) {
136 return "", ReplyBadSyntax
138 if strings
.ToUpper(command
) != strings
.ToUpper(conn
.line
[:len(command
)]) {
139 return "", ReplyLine
{500, "unrecognized command"}
141 return conn
.line
[len(command
):], ReplyOK
144 func (conn
*connection
) doEHLO() {
148 _
, err
:= fmt
.Sscanf(conn
.line
, "%s %s", &cmd
, &conn
.ehlo
)
150 conn
.reply(ReplyBadSyntax
)
155 conn
.writeReply(250, fmt
.Sprintf("Hello %s [%s]", conn
.ehlo
, conn
.remoteAddr
))
157 conn
.tp
.PrintfLine("250-Hello %s [%s]", conn
.ehlo
, conn
.remoteAddr
)
158 if conn
.server
.TLSConfig() != nil && conn
.tlsNc
== nil {
159 conn
.tp
.PrintfLine("250-STARTTLS")
161 conn
.tp
.PrintfLine("250 SIZE %d", 40960000)
164 conn
.log
.Info("doEHLO()", zap
.String("ehlo", conn
.ehlo
))
166 conn
.state
= stateInitial
169 func (conn
*connection
) doSTARTTLS() {
170 if conn
.state
!= stateInitial
{
171 conn
.reply(ReplyBadSequence
)
175 tlsConfig
:= conn
.server
.TLSConfig()
176 if !conn
.esmtp || tlsConfig
== nil {
177 conn
.writeReply(500, "unrecognized command")
181 conn
.log
.Info("doSTARTTLS()")
182 conn
.writeReply(220, "initiate TLS connection")
184 newConn
:= tls
.Server(conn
.nc
, tlsConfig
)
185 if err
:= newConn
.Handshake(); err
!= nil {
190 conn
.tp
= textproto
.NewConn(conn
.tlsNc
)
191 conn
.state
= stateInitial
193 conn
.log
.Info("HELO again")
195 conn
.writeReply(220, fmt
.Sprintf("%s ESMTPS [%s] (mailpopbox)",
196 conn
.server
.Name(), newConn
.LocalAddr()))
199 func (conn
*connection
) doMAIL() {
200 if conn
.state
!= stateInitial
{
201 conn
.reply(ReplyBadSequence
)
205 mailFrom
, reply
:= conn
.parsePath("MAIL FROM:")
206 if reply
!= ReplyOK
{
212 conn
.mailFrom
, err
= mail
.ParseAddress(mailFrom
)
213 if err
!= nil || conn
.mailFrom
== nil {
214 conn
.reply(ReplyBadSyntax
)
218 conn
.log
.Info("doMAIL()", zap
.String("address", conn
.mailFrom
.Address
))
220 conn
.state
= stateMail
224 func (conn
*connection
) doRCPT() {
225 if conn
.state
!= stateMail
&& conn
.state
!= stateRecipient
{
226 conn
.reply(ReplyBadSequence
)
230 rcptTo
, reply
:= conn
.parsePath("RCPT TO:")
231 if reply
!= ReplyOK
{
236 address
, err
:= mail
.ParseAddress(rcptTo
)
238 conn
.reply(ReplyBadSyntax
)
242 if reply
:= conn
.server
.VerifyAddress(*address
); reply
!= ReplyOK
{
243 conn
.log
.Warn("invalid address",
244 zap
.String("address", address
.Address
),
245 zap
.Stringer("reply", reply
))
250 conn
.log
.Info("doRCPT()", zap
.String("address", address
.Address
))
252 conn
.rcptTo
= append(conn
.rcptTo
, *address
)
254 conn
.state
= stateRecipient
258 func (conn
*connection
) doDATA() {
259 if conn
.state
!= stateRecipient
{
260 conn
.reply(ReplyBadSequence
)
264 conn
.writeReply(354, "Start mail input; end with <CRLF>.<CRLF>")
265 conn
.log
.Info("doDATA()")
267 data
, err
:= conn
.tp
.ReadDotBytes()
269 conn
.log
.Error("failed to ReadDotBytes()",
271 zap
.String("bytes", fmt
.Sprintf("%x", data
)))
272 conn
.writeReply(552, "transaction failed")
276 received
:= time
.Now()
278 RemoteAddr
: conn
.remoteAddr
,
280 MailFrom
: *conn
.mailFrom
,
283 ID
: conn
.envelopeID(received
),
286 conn
.log
.Info("received message",
287 zap
.Int("bytes", len(data
)),
288 zap
.Time("date", received
),
289 zap
.String("id", env
.ID
))
291 trace
:= conn
.getReceivedInfo(env
)
293 env
.Data
= append(trace
, data
...)
295 if reply
:= conn
.server
.OnMessageDelivered(env
); reply
!= nil {
296 conn
.log
.Warn("message was rejected", zap
.String("id", env
.ID
))
301 conn
.state
= stateInitial
305 func (conn
*connection
) envelopeID(t time
.Time
) string {
307 rand
.Read(idBytes
[:])
308 return fmt
.Sprintf("m.%d.%x", t
.UnixNano(), idBytes
)
311 func (conn
*connection
) getReceivedInfo(envelope Envelope
) []byte {
312 rhost
, _
, err
:= net
.SplitHostPort(conn
.remoteAddr
.String())
314 rhost
= conn
.remoteAddr
.String()
317 rhosts
, err
:= net
.LookupAddr(rhost
)
319 rhost
= fmt
.Sprintf("%s [%s]", rhosts
[0], rhost
)
322 base
:= fmt
.Sprintf("Received: from %s (%s)\r\n ", conn
.ehlo
, rhost
)
328 if conn
.tlsNc
!= nil {
331 base
+= fmt
.Sprintf("by %s (mailpopbox) with %s id %s\r\n ", conn
.server
.Name(), with
, envelope
.ID
)
333 base
+= fmt
.Sprintf("for <%s>\r\n ", envelope
.RcptTo
[0].Address
)
335 transport
:= conn
.getTransportString()
336 date
:= envelope
.Received
.Format(time
.RFC1123Z
) // Same as RFC 5322 ยง 3.3
337 base
+= fmt
.Sprintf("(using %s);\r\n %s\r\n", transport
, date
)
342 func (conn
*connection
) getTransportString() string {
343 if conn
.tlsNc
== nil {
347 ciphers
:= map[uint16]string{
348 tls
.TLS_RSA_WITH_RC4_128_SHA
: "TLS_RSA_WITH_RC4_128_SHA",
349 tls
.TLS_RSA_WITH_3DES_EDE_CBC_SHA
: "TLS_RSA_WITH_3DES_EDE_CBC_SHA",
350 tls
.TLS_RSA_WITH_AES_128_CBC_SHA
: "TLS_RSA_WITH_AES_128_CBC_SHA",
351 tls
.TLS_RSA_WITH_AES_256_CBC_SHA
: "TLS_RSA_WITH_AES_256_CBC_SHA",
352 tls
.TLS_RSA_WITH_AES_128_GCM_SHA256
: "TLS_RSA_WITH_AES_128_GCM_SHA256",
353 tls
.TLS_RSA_WITH_AES_256_GCM_SHA384
: "TLS_RSA_WITH_AES_256_GCM_SHA384",
354 tls
.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA
: "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA",
355 tls
.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
: "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
356 tls
.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
: "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA",
357 tls
.TLS_ECDHE_RSA_WITH_RC4_128_SHA
: "TLS_ECDHE_RSA_WITH_RC4_128_SHA",
358 tls
.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
: "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA",
359 tls
.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
: "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",
360 tls
.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
: "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",
361 tls
.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
: "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
362 tls
.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
: "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
363 tls
.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
: "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
364 tls
.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
: "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
366 versions
:= map[uint16]string{
367 tls
.VersionSSL30
: "SSLv3.0",
368 tls
.VersionTLS10
: "TLSv1.0",
369 tls
.VersionTLS11
: "TLSv1.1",
370 tls
.VersionTLS12
: "TLSv1.2",
373 state
:= conn
.tlsNc
.ConnectionState()
375 version
:= versions
[state
.Version
]
376 cipher
:= ciphers
[state
.CipherSuite
]
379 version
= fmt
.Sprintf("%x", state
.Version
)
382 cipher
= fmt
.Sprintf("%x", state
.CipherSuite
)
386 if state
.ServerName
!= "" {
387 name
= fmt
.Sprintf(" name=%s", state
.ServerName
)
390 return fmt
.Sprintf("%s cipher=%s%s", version
, cipher
, name
)
393 func (conn
*connection
) doRSET() {
394 conn
.log
.Info("doRSET()")
395 conn
.state
= stateInitial
400 func (conn
*connection
) resetBuffers() {
402 conn
.rcptTo
= make([]mail
.Address
, 0)