Modified address parsing to use the net/mail ParseAddress function.

address.go

@@ -2,18 +2,29 @@ package smtpd
 
 import (
 	"fmt"
+	"net/mail"
 	"strings"
 )
 
 func parseAddress(src string) (string, error) {
 
-	if len(src) == 0 || src[0] != '<' || src[len(src)-1] != '>' {
-		return "", fmt.Errorf("Ill-formatted e-mail address: %s", src)
+	// Mailbox specifications as per RFC5321 must have a local part and a
+	// domain part separated by '@'
+	if strings.Count(src, "@") != 1 {
+		return "", fmt.Errorf("malformed e-mail address: %s", src)
 	}
 
-	if strings.Count(src, "@") > 1 {
-		return "", fmt.Errorf("Ill-formatted e-mail address: %s", src)
+	// While a RFC5321 mailbox specification is not the same as an RFC5322
+	// email address specification, it is better to accept that format and
+	// parse it down to the actual address, as there are a lot of badly
+	// behaving MTAs and MUAs that do it wrongly. It therefore makes sense
+	// to rely on Go's built-in address parser. This does have the benefit
+	// of allowing "email@example.com" as input as thats commonly used,
+	// though not RFC compliant.
+	addr, err := mail.ParseAddress(src)
+	if err != nil {
+		return "", fmt.Errorf("malformed e-mail address: %s", src)
 	}
 
-	return src[1 : len(src)-1], nil
+	return addr.Address, nil
 }