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Diffstat (limited to 'src/bounce/bounce_warn_service.c')
| -rw-r--r-- | src/bounce/bounce_warn_service.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/src/bounce/bounce_warn_service.c b/src/bounce/bounce_warn_service.c new file mode 100644 index 0000000..bbb805d --- /dev/null +++ b/src/bounce/bounce_warn_service.c @@ -0,0 +1,295 @@ +/*++ +/* NAME +/* bounce_warn_service 3 +/* SUMMARY +/* send non-delivery report to sender, server side +/* SYNOPSIS +/* #include "bounce_service.h" +/* +/* int bounce_warn_service(flags, service, queue_name, queue_id, +/* encoding, smtputf8, sender, envid, +/* dsn_ret, templates) +/* int flags; +/* char *service; +/* char *queue_name; +/* char *queue_id; +/* char *encoding; +/* int smtputf8; +/* char *sender; +/* char *envid; +/* int dsn_ret; +/* BOUNCE_TEMPLATES *ts; +/* DESCRIPTION +/* This module implements the server side of the bounce_warn() +/* (send delay notice) request. The logfile +/* is not removed, and a warning is sent instead of a bounce. +/* +/* 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. +/* +/* 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 <dsn_mask.h> +#include <rec_type.h> + +/* Application-specific. */ + +#include "bounce_service.h" + +#define STR vstring_str + +/* bounce_warn_service - send a delayed mail notice */ + +int bounce_warn_service(int unused_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 This service produces RFC 3464-style "delayed mail" reports from + * information in the defer logfile. That same file is used for three + * different types of report: + * + * a) On-demand reports of all delayed deliveries by the mailq(1) command. + * This reports all recipients that have a transient delivery error. + * + * b) 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, subject to + * notify_classes restrictions. + * + * c) RFC 3464-style bounce reports by the bounce(8) service when mail is + * too old. 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, subject to + * notify_classes restrictions. + */ + bounce_info = bounce_mail_init(service, queue_name, queue_id, + encoding, smtputf8, dsn_envid, ts->delay); + +#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_DELAY_NOTICE (notify_mask & MAIL_ERROR_DELAY) + + else if (*recipient == 0) { + if (!SEND_POSTMASTER_DELAY_NOTICE) { + bounce_status = 0; + } else { + postmaster = var_delay_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) + && (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 delay notification: %s", + queue_id, STR(new_id)); + } else { + (void) vstream_fclose(bounce); + if (count == 0) + bounce_status = 0; + } + } + } + } + + /* + * Non-bounce failed. Send a single bounce, 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_DELAY)) > 0 + && bounce_header_dsn(bounce, bounce_info) == 0 + && bounce_diagnostic_dsn(bounce, bounce_info, + DSN_NOTIFY_DELAY) > 0) { + bounce_original(bounce, bounce_info, DSN_RET_HDRS); + bounce_status = post_mail_fclose(bounce); + if (bounce_status == 0) + msg_info("%s: sender delay notification: %s", + queue_id, STR(new_id)); + } else { + (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. + */ + if (bounce_status == 0 && SEND_POSTMASTER_DELAY_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_delay_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 delay notification: %s", + queue_id, STR(new_id)); + } else { + (void) vstream_fclose(bounce); + if (count == 0) + postmaster_status = 0; + } + } + if (postmaster_status) + msg_warn("%s: postmaster notice failed while warning %s", + queue_id, recipient); + } + } + + /* + * Cleanup. + */ + bounce_mail_free(bounce_info); + vstring_free(new_id); + + return (bounce_status); +} |