X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?p=lambdamail.git;a=blobdiff_plain;f=lambdamail.scm;h=683781e9ae0e96b462ca058a12ed138f82be9cc2;hp=3f3594e7d1e34c19debdcd2b89e405302eacfa5d;hb=2d92632d54049b81988e5eabb849eaa4b2248830;hpb=5634d7afd52fe66623d6410ba37b131884db72e3

diff --git a/lambdamail.scm b/lambdamail.scm
index 3f3594e..683781e 100644
--- a/lambdamail.scm
+++ b/lambdamail.scm
@@ -16,13 +16,14 @@
         (chicken condition)
         srfi-1 srfi-13 matchable base64)
 
-(define lambdamail-version "0.0.1")
+(define lambdamail-version "LambdaMail v0.0.1")
 
 (define-record config host port spool-dir user group)
-(define-record message to from text helo user password)
-(define (make-empty-message) (make-message "" "" "" "" "" ""))
+(define-record message to from text user password)
+(define (make-empty-message) (make-message "" "" "" "" ""))
 
-(define outbound-mail-queue '())
+(define (time-stamp)
+  (time->string (seconds->local-time "%d %b %Y %T %z")))
 
 
 ;;; Server initialization
@@ -39,151 +40,220 @@
 (define (run-server config)
   (set-buffering-mode! (current-output-port) #:line)
   (let ((listener (tcp-listen (config-port config) 10 "::")))
-    (print "LambdaMail v" lambdamail-version
+    (print lambdamail-version
            " listening on port " (config-port config) " ...")
     (print "(Host name: " (config-host config)
            ", Spool dir: " (config-spool-dir config) ")")
     (drop-privs config)
-    (server-loop listener config)))
+    (server-loop listener config '())))
 
 
 ;;; Main server loop
 ;;
 
-(define (server-loop listener config)
-  (let-values (((in-port out-port) (tcp-accept listener)))
-    (let-values (((local-ip remote-ip) (tcp-addresses in-port)))
-      (print "Accepted connection from " remote-ip " on " (seconds->string)))
-    (condition-case
-        (let ((smtp-session (make-smtp-session in-port out-port config)))
-          (smtp-session 'greet)
-          (process-smtp smtp-session config))
-      (o (exn)
-         (print-error-message o)))
-    (print "Terminating connection.")
-    (close-input-port in-port)
-    (close-output-port out-port))
-  (print "Attempting delivery of " (length outbound-mail-queue) " mail items.")
-  (set! outbound-mail-queue
-    (filter (lambda (msg) (not (deliver-message msg config)))
-            outbound-mail-queue))
-  (server-loop listener config))
-
-;;; SMTP processing loop
+(define (server-loop listener config undelivered-messages)
+  (let* ((messages (append (receive-messages listener config) undelivered-messages)))
+    (server-loop listener config (deliver-messages config messages))))
+
+
+;;; Receiving messages
 ;;
 
+(define (receive-messages listener config)
+  (let ((messages '()))
+    (let-values (((in-port out-port) (tcp-accept listener)))
+      (let-values (((local-ip remote-ip) (tcp-addresses in-port)))
+        (print "Accepted connection from " remote-ip " on " (time-stamp)))
+      (condition-case
+          (set! messages (process-smtp (make-smtp-session in-port out-port config) config))
+        (o (exn)
+           (print-error-message o)))
+      (print "Terminating connection.")
+      (close-input-port in-port)
+      (close-output-port out-port))
+    messages))
+
 (define (make-smtp-session in-port out-port config)
-  (let ((smtp-say (lambda args (write-line (conc (apply conc args) "\r") out-port)))
-        (user "")
+  (let ((user "")
         (password ""))
-    (lambda msg
-      (match msg
+    (lambda command
+      (match command
         (('get-line) (read-line in-port))
+        (('send strings ...) (write-line (conc (apply conc strings) "\r") out-port))
         (('set-user! u) (set! user u))
         (('set-password! p) (set! password p))
         (('user) user)
-        (('password) password)
-        (('auth-success) (smtp-say "235 Authentication successful"))
-        (('greet) (smtp-say "220 " (config-host config)
-                            " LambdaMail v" lambdamail-version))
-        (('ok) (smtp-say "250 ok"))
-        (('ehlo host)
-         (smtp-say "250-" (config-host config) " Hello " host)
-         (smtp-say "250 AUTH PLAIN"))
-        (('intermediate) (smtp-say "354 intermediate"))
-        (('close) (smtp-say "221 closing transmission channel"))
-        (('not-implemented) (smtp-say "502 command not implemented"))))))
+        (('password) password)))))
+
+(define (smtp-command? cmd-string input-string)
+  (string-prefix? cmd-string (string-downcase input-string)))
+
+(define (smtp-command-args cmd-string input-string)
+  (if (> (string-length input-string) (string-length cmd-string))
+      (string-trim (string-drop input-string (string-length cmd-string)))
+      ""))
 
 (define (process-smtp smtp-session config)
-  (let loop ((msg (make-empty-message)))
-    (let ((line-orig (smtp-session 'get-line)))
-      (if (string? line-orig)
-          (let ((line (string-downcase line-orig)))
-            (print "got " line-orig)
-            (cond
-             ((string-prefix? "helo" line)
-              (message-helo-set! msg (string-drop line (string-length "helo")))
-              (smtp-session 'ok)
-              (loop msg))
-             ((string-prefix? "ehlo" line)
-              (smtp-session 'ehlo (string-drop line (+ 1 (string-length "ehlo"))))
-              (loop msg))
-             ((string-prefix? "auth plain" line)
-              (let* ((auth-string (string-drop line-orig (+ 1 (string-length "auth plain"))))
-                     (auth-decoded (base64-decode auth-string))
-                     (auth-list (string-split auth-decoded "\x00"))
-                     (user (car auth-list))
-                     (password (cadr auth-list)))
-                (smtp-session 'set-user! user)
-                (smtp-session 'set-password! password)
-                (print "Attempted login, user: " user ", password: " password)
-                (smtp-session 'auth-success)
-                (loop msg)))
-             ((string-prefix? "mail from:" line)
-              (message-from-set! msg (string-drop line (string-length "mail from:")))
-              (smtp-session 'ok)
-              (loop msg))
-             ((string-prefix? "rcpt to:" line)
-              (message-to-set! msg (string-drop line (string-length "rcpt to:")))
-              (smtp-session 'ok)
-              (loop msg))
-             ((string-prefix? "data" line)
-              (smtp-session 'intermediate)
-              (let text-loop ((text-line (smtp-session 'get-line))
-                              (text ""))
-                (if (string=? "." text-line)
-                    (message-text-set! msg text)
-                    (text-loop (smtp-session 'get-line)
-                               (conc text text-line "\n"))))
-              (message-user-set! msg (smtp-session 'user))
-              (message-password-set! msg (smtp-session 'password))
-              (set! outbound-mail-queue (cons msg outbound-mail-queue))
-              (smtp-session 'ok)
-              (loop (make-empty-message)))
-             ((string-prefix? "quit" line)
-              (smtp-session 'close)
-              'done)
-             ((string=? "" line)
-              (loop msg))
-             (else
-              (smtp-session 'not-implemented)
-              (loop msg))))
-          'done))))
-
-
-;;; Message delivery
+  (smtp-session 'send "220 " (config-host config) lambdamail-version)
+  (let loop ((msg (make-empty-message))
+             (received-messages '()))
+    (let ((line (smtp-session 'get-line)))
+      (when (string? line)
+        (print "got " line)
+        (cond
+         ((smtp-command? "helo" line)
+          (smtp-session 'send "250 ok")
+          (loop msg received-messages))
+         ((smtp-command? "ehlo" line)
+          (smtp-session 'send
+                        "250-" (config-host config)
+                        " Hello " (smtp-command-args "ehlo" line))
+          (smtp-session 'send "250 AUTH PLAIN")
+          ;; (smtp-session 'send "250 STARTTLS")
+          (loop msg received-messages))
+         ((smtp-command? "auth plain" line)
+          (let* ((auth-string (smtp-command-args "auth plain" line))
+                 (auth-decoded (base64-decode auth-string))
+                 (auth-list (string-split auth-decoded "\x00"))
+                 (user (car auth-list))
+                 (password (cadr auth-list)))
+            (smtp-session 'set-user! user)
+            (smtp-session 'set-password! password)
+            (print "Attempted login, user: " user ", password: " password)
+            (smtp-session 'send "235 authentication successful")
+            (loop msg received-messages)))
+         ((smtp-command? "mail from:" line)
+          (message-from-set! msg (smtp-command-args "mail from:" line))
+          (smtp-session 'send "250 ok")
+          (loop msg received-messages))
+         ((smtp-command? "rcpt to:" line)
+          (message-to-set! msg (smtp-command-args "rcpt to:" line))
+          (smtp-session 'send "250 ok")
+          (loop msg received-messages))
+         ((smtp-command? "data" line)
+          (smtp-session 'send "354 intermediate")
+          (let text-loop ((text (conc "Received: from " (smtp-session 'helo)
+                                      " by " (config-host)
+                                      " for " (message-from msg)
+                                      "; " (time-stamp))))
+            (let ((text-line (smtp-session 'get-line)))
+              (if (string=? "." text-line)
+                  (message-text-set! msg text)
+                  (text-loop (conc text text-line "\n")))))
+          (message-user-set! msg (smtp-session 'user))
+          (message-password-set! msg (smtp-session 'password))
+          (smtp-session 'send "250 ok")
+          (loop (make-empty-message) (cons msg received-messages)))
+         ((smtp-command? "quit" line)
+          (smtp-session 'send "221 closing transmission channel")
+          received-messages)
+         ((string=? "" (string-trim line))
+          (loop msg received-messages))
+         (else
+          (smtp-session 'send "502 command not implemented")
+          (loop msg received-messages)))))))
+
+
+;;; Sending/Delivering messages
 ;;
 
-(define (get-to-addresses config)
+(define (deliver-messages config messages)
+  (print "Attempting delivery of " (length messages) " mail items.")
+  (filter (lambda (msg) (not (deliver-message msg config)))
+          messages))
+
+(define (deliver-message msg config)
+  (condition-case
+      (begin
+        (let* ((local-addresses (get-local-addresses config))
+               (dest (assoc (message-to msg) local-addresses))
+               (orig (assoc (message-from msg) local-addresses)))
+          (cond
+           (dest
+            (let ((dest-dir (cadr dest)))
+              (deliver-message-local msg dest-file))
+            (print "Message DELIVERED (local):"))
+           (orig
+            (let ((password (caddr orig)))
+              (if (and
+                   (string=? (conc "<" (message-user msg) "@" (config-host config) ">")
+                             (message-from msg))
+                   password
+                   (string=? (message-password msg) password))
+                  (begin
+                    (deliver-message-remote msg config)
+                    (print "Message DELIVERED (remote):"))
+                  (print "Message DELIVERY REJECTED (auth failure):"))))
+           (else
+            (print "Message DELIVERY REJECTED (relay forbidden):"))))
+        (print " * From: " (message-from msg))
+        (print " * To: " (message-to msg))
+        #t)
+    (o (exn)
+       (print "Message delivery failed.")
+       (print-error-message o))))
+
+;; Local delivery
+
+(define (get-local-addresses config)
   (map (lambda (p) (cons
                     (conc "<" (car p) "@" (config-host config) ">")
                     (cdr p)))
-       (map (lambda (file) (cons (pathname-file file) file))
-            (glob (conc (config-spool-dir config) "/*")))))
-
-(define (remove-angle-brackets addr)
-  (let ((left-idx (substring-index "<" addr))
-        (right-idx (substring-index ">" addr)))
-    (substring addr (+ left-idx 1) right-idx)))
+       (map (lambda (file)
+              (list (pathname-file file) file
+                    (let ((password-file (conc file ".auth")))
+                      (if (file-exists? password-file)
+                          (with-input-from-file password-file read-line)
+                          #f))))
+            (filter directory-exists?
+                    (glob (conc (config-spool-dir config) "/*"))))))
 
 (define (deliver-message-local msg dest-dir)
-  (print "Delivering to maildir " dest-dir)
   (with-output-to-file (conc dest-dir "/" (current-seconds))
     (lambda ()
       (print (message-text msg)))))
 
-(define (deliver-message msg config)
-  (let ((dest (assoc (message-to msg) (get-to-addresses config))))
-    (if dest
-        (let ((dest-file (cdr dest)))
-          (if (directory-exists? dest-file)
-              (deliver-message-local msg dest-file))
-          (print "Message DELIVERED:"))
-        (print "Message REJECTED:"))
-    (print " * From: " (message-from msg))
-    (print " * To: " (message-to msg)))
-  #t)
 
+;; Remote delivery
+
+(define (get-host-from-email email-string)
+  (car (string-split (cadr (string-split email-string "@")) ">")))
+
+(define (deliver-message-remote msg config)
+  (let ((host (get-host-from-email (message-to msg))))
+    (print "Attempting delivery to host " host)
+    (let-values (((tcp-in tcp-out) (tcp-connect host 2525)))
+      (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")
+                       (smtp-session 'send "quit"))))
+          (close-input-port tcp-in)
+          (close-output-port tcp-out)
+          result)))))
+
+(define ((make-outgoing-smtp-session tcp-in tcp-out) . command)
+  (match command
+    (('expect code)
+     (let ((result (read-line tcp-in)))
+       (print "Expecting " code " got " result)
+       (string-prefix? code result)))
+    (('send strings ...)
+     (print "Sending " (car strings) (if (> (length strings) 1) " ... (truncated)" ""))
+     (let ((processed-string
+            (string-translate* (conc (apply conc strings) "\n")
+                               '(("\n" . "\r\n")))))
+       (write-string processed-string #f tcp-out)))))
 
 ;;; Command line argument parsing
 ;;
@@ -230,4 +300,5 @@
 
 (main)
 
-;; (run-server (make-config "thelambdalab.xyz" 2525 "/var/spool/mail"))
+;; (define (test)
+;;   (run-server (make-config "localhost" 2525 "spool" '() '())))