+/*************************************************
+* Handle SMTP exit when QUIT is not given *
+*************************************************/
+
+/* This function provides a logging/statistics hook for when an SMTP connection
+is dropped on the floor or the other end goes away. It's a global function
+because it's called from receive.c as well as this module. As well as running
+the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
+response, either with a custom message from the ACL, or using a default. There
+is one case, however, when no message is output - after "drop". In that case,
+the ACL that obeyed "drop" has already supplied the custom message, and NULL is
+passed to this function.
+
+In case things go wrong while processing this function, causing an error that
+may re-enter this funtion, there is a recursion check.
+
+Arguments:
+ reason What $smtp_notquit_reason will be set to in the ACL;
+ if NULL, the ACL is not run
+ code The error code to return as part of the response
+ defaultrespond The default message if there's no user_msg
+
+Returns: Nothing
+*/
+
+void
+smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
+{
+int rc;
+uschar *user_msg = NULL;
+uschar *log_msg = NULL;
+
+/* Check for recursive acll */
+
+if (smtp_exit_function_called)
+ {
+ log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
+ reason);
+ return;
+ }
+smtp_exit_function_called = TRUE;
+
+/* Call the not-QUIT ACL, if there is one, unless no reason is given. */
+
+if (acl_smtp_notquit != NULL && reason != NULL)
+ {
+ smtp_notquit_reason = reason;
+ rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
+ &log_msg);
+ if (rc == ERROR)
+ log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
+ log_msg);
+ }
+
+/* Write an SMTP response if we are expected to give one. As the default
+responses are all internal, they should always fit in the buffer, but code a
+warning, just in case. Note that string_vformat() still leaves a complete
+string, even if it is incomplete. */
+
+if (code != NULL && defaultrespond != NULL)
+ {
+ if (user_msg == NULL)
+ {
+ uschar buffer[128];
+ va_list ap;
+ va_start(ap, defaultrespond);
+ if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
+ log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
+ smtp_printf("%s %s\r\n", code, buffer);
+ va_end(ap);
+ }
+ else
+ smtp_respond(code, 3, TRUE, user_msg);
+ mac_smtp_fflush();
+ }
+}
+
+
+
+
+/*************************************************
+* Verify HELO argument *
+*************************************************/
+
+/* This function is called if helo_verify_hosts or helo_try_verify_hosts is
+matched. It is also called from ACL processing if verify = helo is used and
+verification was not previously tried (i.e. helo_try_verify_hosts was not
+matched). The result of its processing is to set helo_verified and
+helo_verify_failed. These variables should both be FALSE for this function to
+be called.
+
+Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
+for IPv6 ::ffff: literals.
+
+Argument: none
+Returns: TRUE if testing was completed;
+ FALSE on a temporary failure
+*/
+
+BOOL
+smtp_verify_helo(void)
+{
+BOOL yield = TRUE;
+
+HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
+ sender_helo_name);
+
+if (sender_helo_name == NULL)
+ {
+ HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
+ }
+
+/* Deal with the case of -bs without an IP address */
+
+else if (sender_host_address == NULL)
+ {
+ HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
+ helo_verified = TRUE;
+ }
+
+/* Deal with the more common case when there is a sending IP address */
+
+else if (sender_helo_name[0] == '[')
+ {
+ helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
+ Ustrlen(sender_host_address)) == 0;
+
+ #if HAVE_IPV6
+ if (!helo_verified)
+ {
+ if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
+ helo_verified = Ustrncmp(sender_helo_name + 1,
+ sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
+ }
+ #endif
+
+ HDEBUG(D_receive)
+ { if (helo_verified) debug_printf("matched host address\n"); }
+ }
+
+/* Do a reverse lookup if one hasn't already given a positive or negative
+response. If that fails, or the name doesn't match, try checking with a forward
+lookup. */
+
+else
+ {
+ if (sender_host_name == NULL && !host_lookup_failed)
+ yield = host_name_lookup() != DEFER;
+
+ /* If a host name is known, check it and all its aliases. */
+
+ if (sender_host_name != NULL)
+ {
+ helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
+
+ if (helo_verified)
+ {
+ HDEBUG(D_receive) debug_printf("matched host name\n");
+ }
+ else
+ {
+ uschar **aliases = sender_host_aliases;
+ while (*aliases != NULL)
+ {
+ helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
+ if (helo_verified) break;
+ }
+ HDEBUG(D_receive)
+ {
+ if (helo_verified)
+ debug_printf("matched alias %s\n", *(--aliases));
+ }
+ }
+ }
+
+ /* Final attempt: try a forward lookup of the helo name */
+
+ if (!helo_verified)
+ {
+ int rc;
+ host_item h;
+ h.name = sender_helo_name;
+ h.address = NULL;
+ h.mx = MX_NONE;
+ h.next = NULL;
+ HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
+ sender_helo_name);
+ rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
+ if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
+ {
+ host_item *hh = &h;
+ while (hh != NULL)
+ {
+ if (Ustrcmp(hh->address, sender_host_address) == 0)
+ {
+ helo_verified = TRUE;
+ HDEBUG(D_receive)
+ debug_printf("IP address for %s matches calling address\n",
+ sender_helo_name);
+ break;
+ }
+ hh = hh->next;
+ }
+ }
+ }
+ }
+
+if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
+return yield;
+}
+
+
+
+
+/*************************************************
+* Send user response message *
+*************************************************/
+
+/* This function is passed a default response code and a user message. It calls
+smtp_message_code() to check and possibly modify the response code, and then
+calls smtp_respond() to transmit the response. I put this into a function
+just to avoid a lot of repetition.
+
+Arguments:
+ code the response code
+ user_msg the user message
+
+Returns: nothing
+*/
+
+static void
+smtp_user_msg(uschar *code, uschar *user_msg)
+{
+int len = 3;
+smtp_message_code(&code, &len, &user_msg, NULL);
+smtp_respond(code, len, TRUE, user_msg);
+}
+
+
+
+
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