;;
;; Intended for a single-user system
-(import tcp6
+(import tcp6 openssl
(chicken port)
(chicken io)
(chicken string)
(chicken random)
srfi-1 srfi-13 matchable base64)
-(define lambdamail-version "LambdaMail v1.6.0")
+(define lambdamail-version "LambdaMail v1.8.0")
-(define-record config host port spool-dir user group)
+(define-record config host port spool-dir user group certfile keyfile)
+(define (tls-supported? config)
+ (and (config-certfile config)
+ (config-keyfile config)))
(define (time-stamp)
(time->string (seconds->local-time) "%d %b %Y %T %z"))
(define (drop-privs config)
(let ((uid (config-user config))
(gid (config-group config)))
- (if (not (null? gid)) ; Group first, since only root can switch groups.
+ (if gid ; Group first, since only root can switch groups.
(set! (current-group-id) gid))
- (if (not (null? uid))
+ (if uid
(set! (current-user-id) uid))))
(define (run-server config)
(set-buffering-mode! (current-output-port) #:line)
(let ((listener (tcp-listen (config-port config) 10 "::")))
- (print lambdamail-version
- " listening on port " (config-port config) " ...")
- (print "(Host name: " (config-host config)
- ", Spool dir: " (config-spool-dir config) ")")
+ (print "Starting " lambdamail-version " with the following configuration:")
+ (print "Host: '" (config-host config) "'\n"
+ "Port: '" (config-port config) "'\n"
+ "Spool dir: '" (config-spool-dir config) "'")
+ (when (tls-supported? config)
+ (print "Cert file: '" (config-certfile config) "'\n"
+ "Key file: '" (config-keyfile config) "'"))
(drop-privs config)
(server-loop listener config '())))
(('get-line) (read-line in-port))
(('send strings ...) (write-line (conc (apply conc strings) "\r") out-port))
(('set-helo! h) (set! helo h))
- (('helo) helo)))))
+ (('helo) helo)
+ (('starttls)
+ (let-values (((in-port-tls out-port-tls)
+ (ssl-start* #t in-port out-port
+ certificate: (config-certfile config)
+ private-key: (config-keyfile config)
+ protocol: (cons 'tlsv12 ssl-max-protocol))))
+ (set! in-port in-port-tls)
+ (set! out-port out-port-tls)))))))
(define (smtp-command? cmd-string input-string)
(string-prefix? cmd-string (string-downcase input-string)))
"250-" (config-host config)
" Hello " (smtp-command-args "ehlo" line))
(smtp-session 'send "250 AUTH PLAIN")
- ;; (smtp-session 'send "250 STARTTLS")
+ (if (tls-supported? config)
+ (smtp-session 'send "250 STARTTLS"))
+ (loop mmsg received-messages))
+ ((smtp-command? "starttls" line)
+ (let ((args (smtp-command-args "starttls" line)))
+ (if (> 0 (string-length args))
+ (smtp-session 'send "501 Syntax error (no parameters allowed)")
+ (begin
+ (smtp-session 'send "220 Ready to start TLS")
+ (smtp-session 'starttls))))
(loop mmsg received-messages))
((smtp-command? "auth plain" line)
(let* ((auth-string (smtp-command-args "auth plain" line))
;; This is a hack - there's no built-in interface to res_query()
;; in chicken, so we have to resort to a system call to dig...
-(define (get-mail-server-for-domain domain)
+(define (get-mail-servers-for-domain domain)
(let* ((mx-lines (let-values (((in out id) (process (conc "dig " domain " mx +short"))))
(with-input-from-port in read-lines)))
(mx-entries (map (lambda (l)
(list (string->number (car s))
(string-drop-right (cadr s) 1)))) ; remove trailing "."
mx-lines))
- (sorted-mx-entries (sort mx-entries (lambda (e f) (< (car e) (car f))))))
+ (sorted-mx-entries (map cadr (sort mx-entries (lambda (e f) (< (car e) (car f)))))))
(if (null? sorted-mx-entries)
- domain ; fall-back to email address domain if no mx entries
- (cadar sorted-mx-entries)))) ; otherwise pick the highest priority server
+ (list domain) ; fall-back to email address domain if no mx entries
+ sorted-mx-entries))) ; otherwise pick the highest priority server
(define (deliver-message-remote msg config)
- (let* ((domain (get-domain-from-email (message-to msg)))
- (mail-server (get-mail-server-for-domain domain)))
- (print "Attempting delivery to " mail-server)
- (let-values (((tcp-in tcp-out) (tcp-connect mail-server 25)))
- (let ((smtp-session (make-outgoing-smtp-session tcp-in tcp-out)))
- (let ((result (and
- (smtp-session 'expect "220")
- (smtp-session 'send "helo " (config-host config))
- (smtp-session 'expect "250")
- (smtp-session 'send "mail from:" (message-from msg))
- (smtp-session 'expect "250")
- (smtp-session 'send "rcpt to:" (message-to msg))
- (smtp-session 'expect "250")
- (smtp-session 'send "data")
- (smtp-session 'expect "354")
- (smtp-session 'send (message-text msg))
- (smtp-session 'send ".")
- (smtp-session 'expect "250" "5") ;Do not try again on rejects.
- (smtp-session 'send "quit"))))
- (close-input-port tcp-in)
- (close-output-port tcp-out)
- (print "Connection closed.")
- (if result
- (print "* MESSAGE DELIVERED (remote)")
- (print "* REMOTE DELIVERY FAILED (unexpected server response)"))
- result)))))
+ (let ((domain (get-domain-from-email (message-to msg))))
+ (let loop ((mail-servers (get-mail-servers-for-domain domain)))
+ (if (null? mail-servers)
+ (begin
+ (print "* REMOTE DELIVERY FAILED (Could not connect to any mail server)")
+ #f)
+ (condition-case
+ (let ((mail-server (car mail-servers)))
+ (print "Attempting delivery to " mail-server)
+ (let-values (((tcp-in tcp-out) (tcp-connect mail-server 25)))
+ (let ((smtp-session (make-outgoing-smtp-session tcp-in tcp-out)))
+ (let ((result (and
+ (smtp-session 'expect "220")
+ (smtp-session 'send "helo " (config-host config))
+ (smtp-session 'expect "250")
+ (smtp-session 'send "mail from:" (message-from msg))
+ (smtp-session 'expect "250")
+ (smtp-session 'send "rcpt to:" (message-to msg))
+ (smtp-session 'expect "250")
+ (smtp-session 'send "data")
+ (smtp-session 'expect "354")
+ (smtp-session 'send (message-text msg))
+ (smtp-session 'send ".")
+ (smtp-session 'expect "250" "5") ;Do not try again on rejects.
+ (smtp-session 'send "quit"))))
+ (close-input-port tcp-in)
+ (close-output-port tcp-out)
+ (print "Connection closed.")
+ (if result
+ (print "* MESSAGE DELIVERED (remote)")
+ (print "* REMOTE DELIVERY FAILED (unexpected server response)"))
+ result))))
+ (o (exn)
+ (print-error-messsage o)
+ (print "* Failed to connect. Trying next server.")
+ (loop (cdr mail-servers))))))))
(define (or-list l)
(fold (lambda (a b) (or a b)) #f l))
(print "Usage:\n"
progname " -h/--help\n"
progname " -v/--version\n"
- progname " [-u/--user UID] [-g/--group GID] hostname [[port [spooldir]]\n"
+ progname " [-u/--user UID] [-g/--group GID] [-c/--certfile] [-k/--keyfile]\n"
+ (make-string (string-length progname)) " hostname [[port [spooldir]]\n"
"\n"
"The -u and -g options can be used to set the UID and GID of the process\n"
- "following the creation of the TCP port listener (which often requires root)."))
+ "following the creation of the TCP port listener (which often requires root).\n"
+ "The -c and -k options specify certificate and key files in PEM format for\n"
+ "optional STARTTLS support."))
(define (print-version)
(print lambdamail-version))
(define (main)
(let ((progname (pathname-file (car (argv))))
- (config (make-config "" 25 "/var/spool/mail" '() '())))
+ (config (make-config "" 25 "/var/spool/mail" #f #f #f #f)))
(if (null? (cdr (argv)))
(print-usage progname)
(let loop ((args (cdr (argv))))
(equal? this-arg "--group"))
(config-group-set! config (string->number (car rest-args)))
(loop (cdr rest-args)))
+ ((or (equal? this-arg "-c")
+ (equal? this-arg "--certfile"))
+ (config-certfile-set! config (car rest-args))
+ (loop (cdr rest-args)))
+ ((or (equal? this-arg "-k")
+ (equal? this-arg "--keyfile"))
+ (config-keyfile-set! config (car rest-args))
+ (loop (cdr rest-args)))
((or (equal? this-arg "-h")
(equal? this-arg "--help"))
(print-usage progname))
The Lambda Lab / projects / lambdamail.git / blobdiff