13 "github.com/uber-go/zap"
19 stateNew state
= iota // Before EHLO.
26 type connection
struct {
35 tls
*tls
.ConnectionState
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
.log
.Info("accepted connection")
58 conn
.writeReply(220, fmt
.Sprintf("%s ESMTP [%s] (mailpopbox)",
59 server
.Name(), netConn
.LocalAddr()))
63 conn
.line
, err
= conn
.tp
.ReadLine()
65 conn
.log
.Error("ReadLine()", zap
.Error(err
))
70 conn
.log
.Info("ReadLine()", zap
.String("line", conn
.line
))
73 if _
, err
= fmt
.Sscanf(conn
.line
, "%s", &cmd
); err
!= nil {
74 conn
.reply(ReplyBadSyntax
)
78 switch strings
.ToUpper(cmd
) {
80 conn
.writeReply(221, "Goodbye")
100 conn
.writeReply(252, "I'll do my best")
102 conn
.writeReply(550, "access denied")
106 conn
.writeReply(250, "https://tools.ietf.org/html/rfc5321")
108 conn
.writeReply(500, "unrecognized command")
113 func (conn
*connection
) reply(reply ReplyLine
) error
{
114 return conn
.writeReply(reply
.Code
, reply
.Message
)
117 func (conn
*connection
) writeReply(code
int, msg
string) error
{
118 conn
.log
.Info("writeReply", zap
.Int("code", code
))
121 err
= conn
.tp
.PrintfLine("%d %s", code
, msg
)
123 err
= conn
.tp
.PrintfLine("%d", code
)
126 conn
.log
.Error("writeReply",
127 zap
.Int("code", code
),
133 // parsePath parses out either a forward-, reverse-, or return-path from the
134 // current connection line. Returns a (valid-path, ReplyOK) if it was
135 // successfully parsed.
136 func (conn
*connection
) parsePath(command
string) (string, ReplyLine
) {
137 if len(conn
.line
) < len(command
) {
138 return "", ReplyBadSyntax
140 if strings
.ToUpper(command
) != strings
.ToUpper(conn
.line
[:len(command
)]) {
141 return "", ReplyLine
{500, "unrecognized command"}
143 params
:= conn
.line
[len(command
):]
144 idx
:= strings
.Index(params
, ">")
146 return "", ReplyBadSyntax
148 return strings
.ToLower(params
[:idx
+1]), ReplyOK
151 func (conn
*connection
) doEHLO() {
155 _
, err
:= fmt
.Sscanf(conn
.line
, "%s %s", &cmd
, &conn
.ehlo
)
157 conn
.reply(ReplyBadSyntax
)
162 conn
.writeReply(250, fmt
.Sprintf("Hello %s [%s]", conn
.ehlo
, conn
.remoteAddr
))
164 conn
.tp
.PrintfLine("250-Hello %s [%s]", conn
.ehlo
, conn
.remoteAddr
)
165 if conn
.server
.TLSConfig() != nil && conn
.tls
== nil {
166 conn
.tp
.PrintfLine("250-STARTTLS")
168 conn
.tp
.PrintfLine("250 SIZE %d", 40960000)
171 conn
.log
.Info("doEHLO()", zap
.String("ehlo", conn
.ehlo
))
173 conn
.state
= stateInitial
176 func (conn
*connection
) doSTARTTLS() {
177 if conn
.state
!= stateInitial
{
178 conn
.reply(ReplyBadSequence
)
182 tlsConfig
:= conn
.server
.TLSConfig()
183 if !conn
.esmtp || tlsConfig
== nil {
184 conn
.writeReply(500, "unrecognized command")
188 conn
.log
.Info("doSTARTTLS()")
189 conn
.writeReply(220, "initiate TLS connection")
191 tlsConn
:= tls
.Server(conn
.nc
, tlsConfig
)
192 if err
:= tlsConn
.Handshake(); err
!= nil {
193 conn
.log
.Error("failed to do TLS handshake", zap
.Error(err
))
198 conn
.tp
= textproto
.NewConn(tlsConn
)
199 conn
.state
= stateNew
201 connState
:= tlsConn
.ConnectionState()
202 conn
.tls
= &connState
204 conn
.log
.Info("TLS connection done", zap
.String("state", conn
.getTransportString()))
207 func (conn
*connection
) doMAIL() {
208 if conn
.state
!= stateInitial
{
209 conn
.reply(ReplyBadSequence
)
213 mailFrom
, reply
:= conn
.parsePath("MAIL FROM:")
214 if reply
!= ReplyOK
{
220 conn
.mailFrom
, err
= mail
.ParseAddress(mailFrom
)
221 if err
!= nil || conn
.mailFrom
== nil {
222 conn
.reply(ReplyBadSyntax
)
226 conn
.log
.Info("doMAIL()", zap
.String("address", conn
.mailFrom
.Address
))
228 conn
.state
= stateMail
232 func (conn
*connection
) doRCPT() {
233 if conn
.state
!= stateMail
&& conn
.state
!= stateRecipient
{
234 conn
.reply(ReplyBadSequence
)
238 rcptTo
, reply
:= conn
.parsePath("RCPT TO:")
239 if reply
!= ReplyOK
{
244 address
, err
:= mail
.ParseAddress(rcptTo
)
246 conn
.reply(ReplyBadSyntax
)
250 if reply
:= conn
.server
.VerifyAddress(*address
); reply
!= ReplyOK
{
251 conn
.log
.Warn("invalid address",
252 zap
.String("address", address
.Address
),
253 zap
.Stringer("reply", reply
))
258 conn
.log
.Info("doRCPT()", zap
.String("address", address
.Address
))
260 conn
.rcptTo
= append(conn
.rcptTo
, *address
)
262 conn
.state
= stateRecipient
266 func (conn
*connection
) doDATA() {
267 if conn
.state
!= stateRecipient
{
268 conn
.reply(ReplyBadSequence
)
272 conn
.writeReply(354, "Start mail input; end with <CRLF>.<CRLF>")
273 conn
.log
.Info("doDATA()")
275 data
, err
:= conn
.tp
.ReadDotBytes()
277 conn
.log
.Error("failed to ReadDotBytes()",
279 zap
.String("bytes", fmt
.Sprintf("%x", data
)))
280 conn
.writeReply(552, "transaction failed")
284 received
:= time
.Now()
286 RemoteAddr
: conn
.remoteAddr
,
288 MailFrom
: *conn
.mailFrom
,
291 ID
: conn
.envelopeID(received
),
294 conn
.log
.Info("received message",
295 zap
.Int("bytes", len(data
)),
296 zap
.Time("date", received
),
297 zap
.String("id", env
.ID
))
299 trace
:= conn
.getReceivedInfo(env
)
301 env
.Data
= append(trace
, data
...)
303 if reply
:= conn
.server
.OnMessageDelivered(env
); reply
!= nil {
304 conn
.log
.Warn("message was rejected", zap
.String("id", env
.ID
))
309 conn
.state
= stateInitial
313 func (conn
*connection
) envelopeID(t time
.Time
) string {
315 rand
.Read(idBytes
[:])
316 return fmt
.Sprintf("m.%d.%x", t
.UnixNano(), idBytes
)
319 func (conn
*connection
) getReceivedInfo(envelope Envelope
) []byte {
320 rhost
, _
, err
:= net
.SplitHostPort(conn
.remoteAddr
.String())
322 rhost
= conn
.remoteAddr
.String()
325 rhosts
, err
:= net
.LookupAddr(rhost
)
327 rhost
= fmt
.Sprintf("%s [%s]", rhosts
[0], rhost
)
330 base
:= fmt
.Sprintf("Received: from %s (%s)\r\n ", conn
.ehlo
, rhost
)
339 base
+= fmt
.Sprintf("by %s (mailpopbox) with %s id %s\r\n ", conn
.server
.Name(), with
, envelope
.ID
)
341 base
+= fmt
.Sprintf("for <%s>\r\n ", envelope
.RcptTo
[0].Address
)
343 transport
:= conn
.getTransportString()
344 date
:= envelope
.Received
.Format(time
.RFC1123Z
) // Same as RFC 5322 ยง 3.3
345 base
+= fmt
.Sprintf("(using %s);\r\n %s\r\n", transport
, date
)
350 func (conn
*connection
) getTransportString() string {
355 ciphers
:= map[uint16]string{
356 tls
.TLS_RSA_WITH_RC4_128_SHA
: "TLS_RSA_WITH_RC4_128_SHA",
357 tls
.TLS_RSA_WITH_3DES_EDE_CBC_SHA
: "TLS_RSA_WITH_3DES_EDE_CBC_SHA",
358 tls
.TLS_RSA_WITH_AES_128_CBC_SHA
: "TLS_RSA_WITH_AES_128_CBC_SHA",
359 tls
.TLS_RSA_WITH_AES_256_CBC_SHA
: "TLS_RSA_WITH_AES_256_CBC_SHA",
360 tls
.TLS_RSA_WITH_AES_128_GCM_SHA256
: "TLS_RSA_WITH_AES_128_GCM_SHA256",
361 tls
.TLS_RSA_WITH_AES_256_GCM_SHA384
: "TLS_RSA_WITH_AES_256_GCM_SHA384",
362 tls
.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA
: "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA",
363 tls
.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
: "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
364 tls
.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
: "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA",
365 tls
.TLS_ECDHE_RSA_WITH_RC4_128_SHA
: "TLS_ECDHE_RSA_WITH_RC4_128_SHA",
366 tls
.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
: "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA",
367 tls
.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
: "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",
368 tls
.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
: "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",
369 tls
.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
: "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
370 tls
.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
: "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
371 tls
.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
: "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
372 tls
.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
: "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
374 versions
:= map[uint16]string{
375 tls
.VersionSSL30
: "SSLv3.0",
376 tls
.VersionTLS10
: "TLSv1.0",
377 tls
.VersionTLS11
: "TLSv1.1",
378 tls
.VersionTLS12
: "TLSv1.2",
383 version
:= versions
[state
.Version
]
384 cipher
:= ciphers
[state
.CipherSuite
]
387 version
= fmt
.Sprintf("%x", state
.Version
)
390 cipher
= fmt
.Sprintf("%x", state
.CipherSuite
)
394 if state
.ServerName
!= "" {
395 name
= fmt
.Sprintf(" name=%s", state
.ServerName
)
398 return fmt
.Sprintf("%s cipher=%s%s", version
, cipher
, name
)
401 func (conn
*connection
) doRSET() {
402 conn
.log
.Info("doRSET()")
403 conn
.state
= stateInitial
408 func (conn
*connection
) resetBuffers() {
410 conn
.rcptTo
= make([]mail
.Address
, 0)