Hello,

  My mail is intended mainly for postfix developers/hackers.

  There's a simple way to make separate message size limit
  depending on the sender/recipient address. I've made some
  changes to the smtpd daemon sources, and it works for me.
  However I do not know are they correct or not, and
  if it is a good idea, I believe many postfix users would
  want to make use of this feature when it will be included
  in the main source tree properly and correctly. And I would
  like to know your comments about the feature and the way
  I've implemented it.

  Looking a bit through the sources I found that the best
  way to do it is by implementing new rule to the access
  tables, so with "OK" and "RELAY" (which is the same to smtpd)
  we have a new records with "SIZE=xxx", where xxx is the
  size in kylobytes. The changes to the smtpd sources are:

  File smtpd.h contains a definition of the record SMTPD_STATE,
  and idea is to use a new field "state->var_message_limit"
  in the record instead of the global "var_message_limit".
  It defaults to the global variable, and is initialized
  by smtpd_state_init() function, and is updated when
  the search is made in function check_table_result() in
  smtpd_check.c.

  However there are some caveats about that. The RCPT command
  is processed after MAIL command. So the SIZE=xxx for recipient
  address will override the size for the sender address. More,
  to use the restriction on recipient addresses,
  "smtpd_delay_reject = no" has to be present in main.cf.

  ... are there any other MTA's that can make mail size restrictions
  depending on sender/recipient?

  The summary patch follows:
  
----------------------//-------------------------
*** smtpd.c Thu Nov 15 16:52:50 2001
--- /home/gnut/posfix-patch/smtpd.c Wed Jan 2 11:19:52 2002
***************
*** 439,447 ****
      state->protocol = "ESMTP";
      smtpd_chat_reply(state, "250-%s", var_myhostname);
      smtpd_chat_reply(state, "250-PIPELINING");
! if (var_message_limit)
        smtpd_chat_reply(state, "250-SIZE %lu",
! (unsigned long) var_message_limit); /* XXX */
      else
        smtpd_chat_reply(state, "250-SIZE");
      smtpd_chat_reply(state, "250-ETRN");
--- 439,447 ----
      state->protocol = "ESMTP";
      smtpd_chat_reply(state, "250-%s", var_myhostname);
      smtpd_chat_reply(state, "250-PIPELINING");
! if (state->var_message_limit)
        smtpd_chat_reply(state, "250-SIZE %lu",
! (unsigned long) state->var_message_limit); /* XXX */
      else
        smtpd_chat_reply(state, "250-SIZE");
      smtpd_chat_reply(state, "250-ETRN");
***************
*** 791,796 ****
--- 791,802 ----
            return (-1);
        }
      }
+ if ((SMTPD_STAND_ALONE(state) || var_smtpd_delay_reject == 0)
+ && (err = smtpd_check_size(state, state->msg_size)) != 0) {
+ smtpd_chat_reply(state, "%s", err);
+ return (-1);
+ }
+
  
      /*
       * Store the recipient. Remember the first one.
*** smtpd.h Wed Jan 2 11:20:11 2002
--- /home/gnut/posfix-patch/smtpd.h Wed Jan 2 11:19:52 2002
***************
*** 66,71 ****
--- 66,72 ----
      char *where;
      int recursion;
      off_t msg_size;
+ off_t var_message_limit;
      int junk_cmds;
  #ifdef USE_SASL_AUTH
      char *sasl_mechanism_list;
*** smtpd_check.c Tue Jul 31 17:26:41 2001
--- /home/gnut/posfix-patch/smtpd_check.c Wed Jan 2 11:19:52 2002
***************
*** 1290,1295 ****
--- 1290,1306 ----
      if (strcasecmp(value, "OK") == 0 || strcasecmp(value, "RELAY") == 0)
        return (SMTPD_CHECK_OK);
  
+ if (strncasecmp(value, "SIZE=",5) == 0) {
+ char * value_size = mystrdup(value+5);
+ if ((state->var_message_limit = off_cvt_string(value + 5)) < 0) {
+ state->var_message_limit = var_message_limit;
+ } else {
+ state->var_message_limit *= 1024;
+ }
+ return (SMTPD_CHECK_OK);
+ }
+
      /*
       * Unfortunately, maps must be declared ahead of time so they can be
       * opened before we go to jail. We could insist that the RHS can only
***************
*** 2161,2167 ****
       */
  #define BLOCKS(x) ((x) / fsbuf.block_size)
  
! if (var_message_limit > 0 && size > var_message_limit) {
        (void) smtpd_check_reject(state, MAIL_ERROR_POLICY,
                                  "552 Message size exceeds fixed limit");
        return (STR(error_text));
--- 2172,2178 ----
       */
  #define BLOCKS(x) ((x) / fsbuf.block_size)
  
! if (state->var_message_limit > 0 && size > state->var_message_limit) {
        (void) smtpd_check_reject(state, MAIL_ERROR_POLICY,
                                  "552 Message size exceeds fixed limit");
        return (STR(error_text));
*** smtpd_state.c Sat Nov 25 03:03:09 2000
--- /home/gnut/posfix-patch/smtpd_state.c Wed Jan 2 11:19:52 2002
***************
*** 90,95 ****
--- 90,96 ----
      state->where = SMTPD_AFTER_CONNECT;
      state->recursion = 0;
      state->msg_size = 0;
+ state->var_message_limit = var_message_limit;
      state->junk_cmds = 0;
  
  #ifdef USE_SASL_AUTH
----------------------//-------------------------

With best wishes, Oles' Hnatkevych, http://gnut.kiev.ua, gnutfc.kiev.ua

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