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+/*++
+/* NAME
+/* bounce_notify_service 3
+/* SUMMARY
+/* send non-delivery report to sender, server side
+/* SYNOPSIS
+/* #include "bounce_service.h"
+/*
+/* int bounce_notify_service(flags, service, queue_name, queue_id,
+/* encoding, smtputf8, sender, dsn_envid,
+/* dsn_ret, templates)
+/* int flags;
+/* char *service;
+/* char *queue_name;
+/* char *queue_id;
+/* char *encoding;
+/* int smtputf8;
+/* char *sender;
+/* char *dsn_envid;
+/* int dsn_ret;
+/* BOUNCE_TEMPLATES *templates;
+/* DESCRIPTION
+/* This module implements the server side of the bounce_flush()
+/* (send bounce message) request.
+/*
+/* When a message bounces, a full copy is sent to the originator,
+/* and an optional copy of the diagnostics with message headers is
+/* sent to the postmaster. The result is non-zero when the operation
+/* should be tried again. Otherwise, the logfile is removed.
+/*
+/* When a bounce is sent, the sender address is the empty
+/* address. When a bounce bounces, an optional double bounce
+/* with the entire undeliverable mail is sent to the postmaster,
+/* with as sender address the double bounce address.
+/* DIAGNOSTICS
+/* Fatal error: error opening existing file.
+/* BUGS
+/* SEE ALSO
+/* bounce(3) basic bounce service client interface
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstream.h>
+#include <name_mask.h>
+#include <stringops.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <mail_queue.h>
+#include <post_mail.h>
+#include <mail_addr.h>
+#include <mail_error.h>
+#include <bounce.h>
+#include <dsn_mask.h>
+#include <rec_type.h>
+
+/* Application-specific. */
+
+#include "bounce_service.h"
+
+#define STR vstring_str
+
+/* bounce_notify_service - send a bounce */
+
+int bounce_notify_service(int flags, char *service, char *queue_name,
+ char *queue_id, char *encoding,
+ int smtputf8, char *recipient,
+ char *dsn_envid, int dsn_ret,
+ BOUNCE_TEMPLATES *ts)
+{
+ BOUNCE_INFO *bounce_info;
+ int bounce_status = 1;
+ int postmaster_status = 1;
+ VSTREAM *bounce;
+ int notify_mask = name_mask(VAR_NOTIFY_CLASSES, mail_error_masks,
+ var_notify_classes);
+ VSTRING *new_id = vstring_alloc(10);
+ char *postmaster;
+ int count;
+
+ /*
+ * Initialize. Open queue file, bounce log, etc.
+ *
+ * XXX DSN The bounce service produces RFC 3464-style "failed mail" reports
+ * from information in two following types of logfile:
+ *
+ * 1 - bounce: this file is used for RFC 3464-style reports of permanent
+ * delivery errors by the bounce(8) service. This reports to the sender
+ * all recipients that have no DSN NOTIFY information (compatibility) and
+ * all recipients that have DSN NOTIFY=FAILURE; this reports to
+ * postmaster all recipients, if postmaster notification is enabled.
+ *
+ * 2 - defer: this file is used for three types of report:
+ *
+ * 2a) RFC 3464-style "mail is too old" reports by the bounce(8) service.
+ * This reports to the sender all recipients that have no DSN NOTIFY
+ * information (compatibility) and all recipients that have DSN
+ * NOTIFY=FAILURE; this reports to postmaster all recipients, if
+ * postmaster notification is enabled.
+ *
+ * Other reports that other servers produce from the defer logfile:
+ *
+ * 2b) On-demand reports of all delayed deliveries by the showq(8) service
+ * and mailq(1) command. This reports all recipients that have a
+ * transient delivery error.
+ *
+ * 2c) RFC 3464-style "delayed mail" notifications by the defer(8) service.
+ * This reports to the sender all recipients that have no DSN NOTIFY
+ * information (compatibility) and all recipients that have DSN
+ * NOTIFY=DELAY; this reports to postmaster all recipients, if postmaster
+ * notification is enabled.
+ */
+ bounce_info = bounce_mail_init(service, queue_name, queue_id,
+ encoding, smtputf8, dsn_envid,
+ ts->failure);
+
+#define NULL_SENDER MAIL_ADDR_EMPTY /* special address */
+#define NULL_TRACE_FLAGS 0
+
+ /*
+ * The choice of sender address depends on the recipient address. For a
+ * single bounce (a non-delivery notification to the message originator),
+ * the sender address is the empty string. For a double bounce (typically
+ * a failed single bounce, or a postmaster notification that was produced
+ * by any of the mail processes) the sender address is defined by the
+ * var_double_bounce_sender configuration variable. When a double bounce
+ * cannot be delivered, the queue manager blackholes the resulting triple
+ * bounce message.
+ */
+
+ /*
+ * Double bounce failed. Never send a triple bounce.
+ *
+ * However, this does not prevent double bounces from bouncing on other
+ * systems. In order to cope with this, either the queue manager must
+ * recognize the double-bounce recipient address and discard mail, or
+ * every delivery agent must recognize the double-bounce sender address
+ * and substitute something else so mail does not come back at us.
+ */
+ if (strcasecmp_utf8(recipient, mail_addr_double_bounce()) == 0) {
+ msg_warn("%s: undeliverable postmaster notification discarded",
+ queue_id);
+ bounce_status = 0;
+ }
+
+ /*
+ * Single bounce failed. Optionally send a double bounce to postmaster,
+ * subject to notify_classes restrictions.
+ */
+#define ANY_BOUNCE (MAIL_ERROR_2BOUNCE | MAIL_ERROR_BOUNCE)
+#define SEND_POSTMASTER_ANY_BOUNCE_NOTICE (notify_mask & ANY_BOUNCE)
+
+ else if (*recipient == 0) {
+ if (!SEND_POSTMASTER_ANY_BOUNCE_NOTICE) {
+ bounce_status = 0;
+ } else {
+ postmaster = var_2bounce_rcpt;
+ if ((bounce = post_mail_fopen_nowait(mail_addr_double_bounce(),
+ postmaster,
+ MAIL_SRC_MASK_BOUNCE,
+ NULL_TRACE_FLAGS,
+ smtputf8,
+ new_id)) != 0) {
+
+ /*
+ * Double bounce to Postmaster. This is the last opportunity
+ * for this message to be delivered. Send the text with
+ * reason for the bounce, and the headers of the original
+ * message. Don't bother sending the boiler-plate text.
+ */
+ count = -1;
+ if (bounce_header(bounce, bounce_info, postmaster,
+ POSTMASTER_COPY) == 0
+ && (count = bounce_diagnostic_log(bounce, bounce_info,
+ DSN_NOTIFY_OVERRIDE)) > 0
+ && bounce_header_dsn(bounce, bounce_info) == 0
+ && bounce_diagnostic_dsn(bounce, bounce_info,
+ DSN_NOTIFY_OVERRIDE) > 0) {
+ bounce_original(bounce, bounce_info, DSN_RET_FULL);
+ bounce_status = post_mail_fclose(bounce);
+ if (bounce_status == 0)
+ msg_info("%s: postmaster non-delivery notification: %s",
+ queue_id, STR(new_id));
+ } else {
+ /* No applicable recipients found - cancel this notice. */
+ (void) vstream_fclose(bounce);
+ if (count == 0)
+ bounce_status = 0;
+ }
+ }
+ }
+ }
+
+ /*
+ * Non-bounce failed. Send a single bounce to the sender, subject to DSN
+ * NOTIFY restrictions.
+ */
+ else {
+ if ((bounce = post_mail_fopen_nowait(NULL_SENDER, recipient,
+ MAIL_SRC_MASK_BOUNCE,
+ NULL_TRACE_FLAGS,
+ smtputf8,
+ new_id)) != 0) {
+
+ /*
+ * Send the bounce message header, some boilerplate text that
+ * pretends that we are a polite mail system, the text with
+ * reason for the bounce, and a copy of the original message.
+ */
+ count = -1;
+ if (bounce_header(bounce, bounce_info, recipient,
+ NO_POSTMASTER_COPY) == 0
+ && bounce_boilerplate(bounce, bounce_info) == 0
+ && (count = bounce_diagnostic_log(bounce, bounce_info,
+ DSN_NOTIFY_FAILURE)) > 0
+ && bounce_header_dsn(bounce, bounce_info) == 0
+ && bounce_diagnostic_dsn(bounce, bounce_info,
+ DSN_NOTIFY_FAILURE) > 0) {
+ bounce_original(bounce, bounce_info, dsn_ret ?
+ dsn_ret : DSN_RET_FULL);
+ bounce_status = post_mail_fclose(bounce);
+ if (bounce_status == 0)
+ msg_info("%s: sender non-delivery notification: %s",
+ queue_id, STR(new_id));
+ } else {
+ /* No applicable recipients found - cancel this notice. */
+ (void) vstream_fclose(bounce);
+ if (count == 0)
+ bounce_status = 0;
+ }
+ }
+
+ /*
+ * Optionally, send a postmaster notice, subject to notify_classes
+ * restrictions.
+ *
+ * This postmaster notice is not critical, so if it fails don't
+ * retransmit the bounce that we just generated, just log a warning.
+ */
+#define SEND_POSTMASTER_SINGLE_BOUNCE_NOTICE (notify_mask & MAIL_ERROR_BOUNCE)
+
+ if (bounce_status == 0 && SEND_POSTMASTER_SINGLE_BOUNCE_NOTICE
+ && strcasecmp_utf8(recipient, mail_addr_double_bounce()) != 0) {
+
+ /*
+ * Send the text with reason for the bounce, and the headers of
+ * the original message. Don't bother sending the boiler-plate
+ * text. This postmaster notice is not critical, so if it fails
+ * don't retransmit the bounce that we just generated, just log a
+ * warning.
+ */
+ postmaster = var_bounce_rcpt;
+ if ((bounce = post_mail_fopen_nowait(mail_addr_double_bounce(),
+ postmaster,
+ MAIL_SRC_MASK_BOUNCE,
+ NULL_TRACE_FLAGS,
+ smtputf8,
+ new_id)) != 0) {
+ count = -1;
+ if (bounce_header(bounce, bounce_info, postmaster,
+ POSTMASTER_COPY) == 0
+ && (count = bounce_diagnostic_log(bounce, bounce_info,
+ DSN_NOTIFY_OVERRIDE)) > 0
+ && bounce_header_dsn(bounce, bounce_info) == 0
+ && bounce_diagnostic_dsn(bounce, bounce_info,
+ DSN_NOTIFY_OVERRIDE) > 0) {
+ bounce_original(bounce, bounce_info, DSN_RET_HDRS);
+ postmaster_status = post_mail_fclose(bounce);
+ if (postmaster_status == 0)
+ msg_info("%s: postmaster non-delivery notification: %s",
+ queue_id, STR(new_id));
+ } else {
+ /* No applicable recipients found - cancel this notice. */
+ (void) vstream_fclose(bounce);
+ if (count == 0)
+ postmaster_status = 0;
+ }
+ }
+ if (postmaster_status)
+ msg_warn("%s: postmaster notice failed while bouncing to %s",
+ queue_id, recipient);
+ }
+ }
+
+ /*
+ * Optionally, delete the recipients from the queue file.
+ */
+ if (bounce_status == 0 && (flags & BOUNCE_FLAG_DELRCPT))
+ bounce_delrcpt(bounce_info);
+
+ /*
+ * Examine the completion status. Delete the bounce log file only when
+ * the bounce was posted successfully, and only if we are bouncing for
+ * real, not just warning.
+ */
+ if (bounce_status == 0 && mail_queue_remove(service, queue_id)
+ && errno != ENOENT)
+ msg_fatal("remove %s %s: %m", service, queue_id);
+
+ /*
+ * Cleanup.
+ */
+ bounce_mail_free(bounce_info);
+ vstring_free(new_id);
+
+ return (bounce_status);
+}