mox!

mox-/lookup.go

@@ -0,0 +1,66 @@
+package mox
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/mjl-/mox/config"
+	"github.com/mjl-/mox/dns"
+	"github.com/mjl-/mox/smtp"
+)
+
+var (
+	ErrDomainNotFound  = errors.New("domain not found")
+	ErrAccountNotFound = errors.New("account not found")
+)
+
+// FindAccount lookups the account for localpart and domain.
+//
+// Can return ErrDomainNotFound and ErrAccountNotFound.
+func FindAccount(localpart smtp.Localpart, domain dns.Domain, allowPostmaster bool) (accountName string, canonicalAddress string, dest config.Destination, rerr error) {
+	if strings.EqualFold(string(localpart), "postmaster") {
+		localpart = "postmaster"
+	}
+	var zerodomain dns.Domain
+	if localpart == "postmaster" && domain == zerodomain {
+		if !allowPostmaster {
+			return "", "", config.Destination{}, ErrAccountNotFound
+		}
+		return Conf.Static.Postmaster.Account, "postmaster", config.Destination{Mailbox: Conf.Static.Postmaster.Mailbox}, nil
+	}
+
+	d, ok := Conf.Domain(domain)
+	if !ok {
+		return "", "", config.Destination{}, ErrDomainNotFound
+	}
+
+	localpart, err := CanonicalLocalpart(localpart, d)
+	if err != nil {
+		return "", "", config.Destination{}, fmt.Errorf("%w: %s", ErrAccountNotFound, err)
+	}
+	canonical := smtp.NewAddress(localpart, domain).String()
+
+	accAddr, ok := Conf.AccountDestination(canonical)
+	if !ok {
+		return "", "", config.Destination{}, ErrAccountNotFound
+	}
+	return accAddr.Account, canonical, accAddr.Destination, nil
+}
+
+// CanonicalLocalpart returns the canonical localpart, removing optional catchall
+// separator, and optionally lower-casing the string.
+func CanonicalLocalpart(localpart smtp.Localpart, d config.Domain) (smtp.Localpart, error) {
+	if d.LocalpartCatchallSeparator != "" {
+		t := strings.SplitN(string(localpart), d.LocalpartCatchallSeparator, 2)
+		localpart = smtp.Localpart(t[0])
+		if localpart == "" {
+			return "", fmt.Errorf("empty localpart")
+		}
+	}
+
+	if !d.LocalpartCaseSensitive {
+		localpart = smtp.Localpart(strings.ToLower(string(localpart)))
+	}
+	return localpart, nil
+}