implement "future release"

the smtp extension, rfc 4865.
also implement in the webmail.
the queueing/delivery part hardly required changes: we just set the first
delivery time in the future instead of immediately.

still have to find the first client that implements it.

dsn/dsn.go

@@ -48,6 +48,12 @@ type Message struct {
 	// mail user-agents will thread the DSN with the original message.
 	References string
 
+	// For message submitted with FUTURERELEASE SMTP extension. Value is either "for;"
+	// plus original interval in seconds or "until;" plus original UTC RFC3339
+	// date-time.
+	FutureReleaseRequest string
+	// ../rfc/4865:315
+
 	// Human-readable text explaining the failure. Line endings should be
 	// bare newlines, not \r\n. They are converted to \r\n when composing.
 	TextBody string
@@ -230,6 +236,10 @@ func (m *Message) Compose(log mlog.Log, smtputf8 bool) ([]byte, error) {
 		status("Received-From-MTA", fmt.Sprintf("dns;%s (%s)", m.ReceivedFromMTA.Name, smtp.AddressLiteral(m.ReceivedFromMTA.ConnIP)))
 	}
 	status("Arrival-Date", m.ArrivalDate.Format(message.RFC5322Z)) // ../rfc/3464:758
+	if m.FutureReleaseRequest != "" {
+		// ../rfc/4865:320
+		status("Future-Release-Request", m.FutureReleaseRequest)
+	}
 
 	// Then per-recipient fields. ../rfc/3464:769
 	// todo: should also handle other address types. at least recognize "unknown". Probably just store this field. ../rfc/3464:819

dsn/dsn_test.go

@@ -85,9 +85,10 @@ func TestDSN(t *testing.T) {
 		MessageID: "test@localhost",
 		TextBody:  "delivery failure\n",
 
-		ReportingMTA:    "mox.example",
-		ReceivedFromMTA: smtp.Ehlo{Name: xparseIPDomain("relay.example"), ConnIP: net.ParseIP("10.10.10.10")},
-		ArrivalDate:     now,
+		ReportingMTA:         "mox.example",
+		ReceivedFromMTA:      smtp.Ehlo{Name: xparseIPDomain("relay.example"), ConnIP: net.ParseIP("10.10.10.10")},
+		ArrivalDate:          now,
+		FutureReleaseRequest: "for;123",
 
 		Recipients: []Recipient{
 			{

queue/dsn.go

@@ -128,8 +128,9 @@ func deliverDSN(ctx context.Context, log mlog.Log, m Msg, remoteMTA dsn.NameIP,
 		References: m.MessageID,
 		TextBody:   textBody,
 
-		ReportingMTA: mox.Conf.Static.HostnameDomain.ASCII,
-		ArrivalDate:  m.Queued,
+		ReportingMTA:         mox.Conf.Static.HostnameDomain.ASCII,
+		ArrivalDate:          m.Queued,
+		FutureReleaseRequest: m.FutureReleaseRequest,
 
 		Recipients: []dsn.Recipient{
 			{

queue/queue.go

@@ -67,6 +67,9 @@ var jitter = mox.NewPseudoRand()
 var DBTypes = []any{Msg{}} // Types stored in DB.
 var DB *bstore.DB          // Exported for making backups.
 
+// Allow requesting delivery starting from up to this interval from time of submission.
+const FutureReleaseIntervalMax = 60 * 24 * time.Hour
+
 // Set for mox localserve, to prevent queueing.
 var Localserve bool
 
@@ -122,6 +125,12 @@ type Msg struct {
 	// i.e. falling back to SMTP delivery with unverified STARTTLS or plain text.
 	RequireTLS *bool
 	// ../rfc/8689:250
+
+	// For DSNs, where the original FUTURERELEASE value must be included as per-message
+	// field. This field should be of the form "for;" plus interval, or "until;" plus
+	// utc date-time.
+	FutureReleaseRequest string
+	// ../rfc/4865:305
 }
 
 // Sender of message as used in MAIL FROM.
@@ -200,6 +209,7 @@ func Count(ctx context.Context) (int, error) {
 
 // MakeMsg is a convenience function that sets the commonly used fields for a Msg.
 func MakeMsg(senderAccount string, sender, recipient smtp.Path, has8bit, smtputf8 bool, size int64, messageID string, prefix []byte, requireTLS *bool) Msg {
+	now := time.Now()
 	return Msg{
 		SenderAccount:      mox.Conf.Static.Postmaster.Account,
 		SenderLocalpart:    sender.Localpart,
@@ -212,6 +222,9 @@ func MakeMsg(senderAccount string, sender, recipient smtp.Path, has8bit, smtputf
 		MessageID:          messageID,
 		MsgPrefix:          prefix,
 		RequireTLS:         requireTLS,
+		Queued:             now,
+		NextAttempt:        now,
+		RecipientDomainStr: formatIPDomain(recipient.IPDomain),
 	}
 }
 
@@ -228,12 +241,6 @@ func Add(ctx context.Context, log mlog.Log, qm *Msg, msgFile *os.File) error {
 	if qm.ID != 0 {
 		return fmt.Errorf("id of queued message must be 0")
 	}
-	qm.Queued = time.Now()
-	qm.DialedIPs = nil
-	qm.NextAttempt = qm.Queued
-	qm.LastAttempt = nil
-	qm.LastError = ""
-	qm.RecipientDomainStr = formatIPDomain(qm.RecipientDomain)
 
 	if Localserve {
 		if qm.SenderAccount == "" {

rfc/index.txt

@@ -66,7 +66,8 @@ https://www.iana.org/assignments/message-headers/message-headers.xhtml
 3974	-	-	SMTP Operational Experience in Mixed IPv4/v6 Environments
 4409	-	Obs	(RFC 6409) Message Submission for Mail
 4468	Roadmap	-	Message Submission BURL Extension
-4865	Roadmap	-	SMTP Submission Service Extension for Future Message Release
+4865	Yes	-	SMTP Submission Service Extension for Future Message Release
+4865-eid2040	-	errata: Internet-style-date-time-UTC -> date-time from rfc 3339
 4954	Yes	-	SMTP Service Extension for Authentication
 5068	-	-	Email Submission Operations: Access and Accountability Requirements
 5248	-	-	A Registry for SMTP Enhanced Mail System Status Codes
@@ -83,6 +84,7 @@ https://www.iana.org/assignments/message-headers/message-headers.xhtml
 6532	Yes	-	Internationalized Email Headers
 6533	Yes	-	Internationalized Delivery Status and Disposition Notifications
 6647	Partial	-	Email Greylisting: An Applicability Statement for SMTP
+6710	No	-	Simple Mail Transfer Protocol Extension for Message Transfer Priorities
 6729	No	-	Indicating Email Handling States in Trace Fields
 6857	No	-	Post-Delivery Message Downgrading for Internationalized Email Messages
 7293	No	-	The Require-Recipient-Valid-Since Header Field and SMTP Service Extension

smtp/codes.go

@@ -132,14 +132,16 @@ var (
 	SePol7PasswdTransitionReq12 = "7.12" // ../rfc/4954:578
 	SePol7AccountDisabled13     = "7.13" // ../rfc/5248:399
 	SePol7TrustReq14            = "7.14" // ../rfc/5248:418
-	SePol7NoDKIMPass20          = "7.20" // ../rfc/7372:137
-	SePol7NoDKIMAccept21        = "7.21" // ../rfc/7372:148
-	SePol7NoDKIMAuthorMatch22   = "7.22" // ../rfc/7372:175
-	SePol7SPFResultFail23       = "7.23" // ../rfc/7372:192
-	SePol7SPFError24            = "7.24" // ../rfc/7372:204
-	SePol7RevDNSFail25          = "7.25" // ../rfc/7372:233
-	SePol7MultiAuthFails26      = "7.26" // ../rfc/7372:246
-	SePol7SenderHasNullMX27     = "7.27" // ../rfc/7505:246
-	SePol7ARCFail               = "7.29" // ../rfc/8617:1438
-	SePol7MissingReqTLS         = "7.30" // ../rfc/8689:448
+	// todo spec: duplicate spec of 7.16 ../rfc/4865:412 ../rfc/6710:878
+	// todo spec: duplicate spec of 7.17 ../rfc/4865:418 ../rfc/7293:1137
+	SePol7NoDKIMPass20        = "7.20" // ../rfc/7372:137
+	SePol7NoDKIMAccept21      = "7.21" // ../rfc/7372:148
+	SePol7NoDKIMAuthorMatch22 = "7.22" // ../rfc/7372:175
+	SePol7SPFResultFail23     = "7.23" // ../rfc/7372:192
+	SePol7SPFError24          = "7.24" // ../rfc/7372:204
+	SePol7RevDNSFail25        = "7.25" // ../rfc/7372:233
+	SePol7MultiAuthFails26    = "7.26" // ../rfc/7372:246
+	SePol7SenderHasNullMX27   = "7.27" // ../rfc/7505:246
+	SePol7ARCFail             = "7.29" // ../rfc/8617:1438
+	SePol7MissingReqTLS       = "7.30" // ../rfc/8689:448
 )

smtpserver/parse.go

@@ -6,6 +6,7 @@ import (
 	"net"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/mjl-/mox/dns"
 	"github.com/mjl-/mox/mox-"
@@ -137,7 +138,7 @@ func (p *parser) peekchar() rune {
 	return -1
 }
 
-func (p *parser) takefn1(what string, fn func(c rune, i int) bool) string {
+func (p *parser) xtakefn1(what string, fn func(c rune, i int) bool) string {
 	if p.empty() {
 		p.xerrorf("need at least one char for %s", what)
 	}
@@ -152,7 +153,7 @@ func (p *parser) takefn1(what string, fn func(c rune, i int) bool) string {
 	return p.remainder()
 }
 
-func (p *parser) takefn1case(what string, fn func(c rune, i int) bool) string {
+func (p *parser) xtakefn1case(what string, fn func(c rune, i int) bool) string {
 	if p.empty() {
 		p.xerrorf("need at least one char for %s", what)
 	}
@@ -167,7 +168,7 @@ func (p *parser) takefn1case(what string, fn func(c rune, i int) bool) string {
 	return p.remainder()
 }
 
-func (p *parser) takefn(fn func(c rune, i int) bool) string {
+func (p *parser) xtakefn(fn func(c rune, i int) bool) string {
 	for i, c := range p.upper[p.o:] {
 		if !fn(c, i) {
 			return p.xtaken(i)
@@ -183,7 +184,7 @@ func (p *parser) takefn(fn func(c rune, i int) bool) string {
 // ../rfc/5321:2260
 func (p *parser) xrawReversePath() string {
 	p.xtake("<")
-	s := p.takefn(func(c rune, i int) bool {
+	s := p.xtakefn(func(c rune, i int) bool {
 		return c != '>'
 	})
 	p.xtake(">")
@@ -261,7 +262,7 @@ func (p *parser) xdomain() dns.Domain {
 // ../rfc/5321:2303
 // ../rfc/5321:2303 ../rfc/6531:411
 func (p *parser) xsubdomain() string {
-	return p.takefn1("subdomain", func(c rune, i int) bool {
+	return p.xtakefn1("subdomain", func(c rune, i int) bool {
 		return c >= '0' && c <= '9' || c >= 'A' && c <= 'Z' || i > 0 && c == '-' || c > 0x7f && p.smtputf8
 	})
 }
@@ -275,7 +276,7 @@ func (p *parser) xmailbox() smtp.Path {
 
 // ../rfc/5321:2307
 func (p *parser) xldhstr() string {
-	return p.takefn1("ldh-str", func(c rune, i int) bool {
+	return p.xtakefn1("ldh-str", func(c rune, i int) bool {
 		return c >= 'A' && c <= 'Z' || c >= '0' && c <= '9' || i == 0 && c == '-'
 	})
 }
@@ -295,7 +296,7 @@ func (p *parser) xipdomain(isehlo bool) dns.IPDomain {
 			}
 			ipv6 = true
 		}
-		ipaddr := p.takefn1("address literal", func(c rune, i int) bool {
+		ipaddr := p.xtakefn1("address literal", func(c rune, i int) bool {
 			return c != ']'
 		})
 		p.take("]")
@@ -402,7 +403,7 @@ func (p *parser) xchar() rune {
 
 // ../rfc/5321:2320 ../rfc/6531:414
 func (p *parser) xatom(islocalpart bool) string {
-	return p.takefn1("atom", func(c rune, i int) bool {
+	return p.xtakefn1("atom", func(c rune, i int) bool {
 		switch c {
 		case '!', '#', '$', '%', '&', '\'', '*', '+', '-', '/', '=', '?', '^', '_', '`', '{', '|', '}', '~':
 			return true
@@ -424,23 +425,23 @@ func (p *parser) xstring() string {
 
 // ../rfc/5321:2279
 func (p *parser) xparamKeyword() string {
-	return p.takefn1("parameter keyword", func(c rune, i int) bool {
+	return p.xtakefn1("parameter keyword", func(c rune, i int) bool {
 		return c >= '0' && c <= '9' || c >= 'A' && c <= 'Z' || (i > 0 && c == '-')
 	})
 }
 
 // ../rfc/5321:2281 ../rfc/6531:422
 func (p *parser) xparamValue() string {
-	return p.takefn1("parameter value", func(c rune, i int) bool {
+	return p.xtakefn1("parameter value", func(c rune, i int) bool {
 		return c > ' ' && c < 0x7f && c != '=' || (c > 0x7f && p.smtputf8)
 	})
 }
 
 // for smtp parameters that take a numeric parameter with specified number of
 // digits, eg SIZE=... for MAIL FROM.
-func (p *parser) xnumber(maxDigits int) int64 {
-	s := p.takefn1("number", func(c rune, i int) bool {
-		return c >= '0' && c <= '9' && i < maxDigits
+func (p *parser) xnumber(maxDigits int, allowZero bool) int64 {
+	s := p.xtakefn1("number", func(c rune, i int) bool {
+		return (c >= '1' && c <= '9' || c == '0' && (i > 0 || allowZero)) && i < maxDigits
 	})
 	v, err := strconv.ParseInt(s, 10, 64)
 	if err != nil {
@@ -449,10 +450,54 @@ func (p *parser) xnumber(maxDigits int) int64 {
 	return v
 }
 
+// parse date-time in UTC form. ../rfc/4865:147 ../rfc/4865-eid2040
+func (p *parser) xdatetimeutc() (time.Time, string) {
+	// ../rfc/3339:422
+	xdash := func() string {
+		p.xtake("-")
+		return "-"
+	}
+	xcolon := func() string {
+		p.xtake(":")
+		return ":"
+	}
+	xdigits := func(n int) string {
+		s := p.xtakefn1("digits", func(c rune, i int) bool {
+			return c >= '0' && c <= '9' && i < n
+		})
+		if len(s) != n {
+			p.xerrorf("parsing date-time: got %d digits, need %d", len(s), n)
+		}
+		return s
+	}
+	s := xdigits(4) + xdash() + xdigits(2) + xdash() + xdigits(2)
+	if !p.hasPrefix("T") {
+		p.xerrorf("expected T for date-time separator")
+	}
+	s += p.xtaken(1) + xdigits(2) + xcolon() + xdigits(2) + xcolon() + xdigits(2)
+	layout := time.RFC3339
+	if p.take(".") {
+		layout = time.RFC3339Nano
+		s += "." + p.xtakefn1("digits", func(c rune, i int) bool {
+			return c >= '0' && c <= '9'
+		})
+	}
+	if !p.hasPrefix("Z") {
+		p.xerrorf("expected Z for date-time utc timezone")
+	}
+	s += p.xtaken(1)
+
+	t, err := time.Parse(layout, s)
+	if err != nil {
+		p.xerrorf("bad utc date-time %q: %s", s, err)
+	}
+	return t, s
+}
+
 // sasl mechanism, for AUTH command.
 // ../rfc/4422:436
 func (p *parser) xsaslMech() string {
-	return p.takefn1case("sasl-mech", func(c rune, i int) bool {
+	return p.xtakefn1case("sasl-mech", func(c rune, i int) bool {
 		return i < 20 && (c >= 'A' && c <= 'Z' || c >= '0' && c <= '9' || c == '-' || c == '_')
 	})
 }