1 /*        $NetBSD: defer.c,v 1.4 2025/02/25 19:15:45 christos Exp $   */
2 
3 /*++
4 /* NAME
5 /*        defer 3
6 /* SUMMARY
7 /*        defer service client interface
8 /* SYNOPSIS
9 /*        #include <defer.h>
10 /*
11 /*        int       defer_append(flags, id, stats, rcpt, relay, dsn)
12 /*        int       flags;
13 /*        const char *id;
14 /*        MSG_STATS *stats;
15 /*        RECIPIENT *rcpt;
16 /*        const char *relay;
17 /*        DSN       *dsn;
18 /*
19 /*        int       defer_flush(flags, queue, id, encoding, sendopts, sender,
20 /*                                      dsn_envid, dsn_ret)
21 /*        int       flags;
22 /*        const char *queue;
23 /*        const char *id;
24 /*        const char *encoding;
25 /*        int       sendopts;
26 /*        const char *sender;
27 /*        const char *dsn_envid;
28 /*        int       dsn_ret;
29 /*
30 /*        int       defer_warn(flags, queue, id, encoding, sendopts, sender,
31                                         dsn_envid, dsn_ret)
32 /*        int       flags;
33 /*        const char *queue;
34 /*        const char *id;
35 /*        const char *encoding;
36 /*        int       sendopts;
37 /*        const char *sender;
38 /*        const char *dsn_envid;
39 /*        int       dsn_ret;
40 /*
41 /*        int       defer_one(flags, queue, id, encoding, sendopts, sender,
42 /*                                      dsn_envid, ret, stats, recipient, relay, dsn)
43 /*        int       flags;
44 /*        const char *queue;
45 /*        const char *id;
46 /*        const char *encoding;
47 /*        int       sendopts;
48 /*        const char *sender;
49 /*        const char *dsn_envid;
50 /*        int       dsn_ret;
51 /*        MSG_STATS *stats;
52 /*        RECIPIENT *rcpt;
53 /*        const char *relay;
54 /*        DSN       *dsn;
55 /* INTERNAL API
56 /*        int       defer_append_intern(flags, id, stats, rcpt, relay, dsn)
57 /*        int       flags;
58 /*        const char *id;
59 /*        MSG_STATS *stats;
60 /*        RECIPIENT *rcpt;
61 /*        const char *relay;
62 /* DESCRIPTION
63 /*        This module implements a client interface to the defer service,
64 /*        which maintains a per-message logfile with status records for
65 /*        each recipient whose delivery is deferred, and the dsn_text why.
66 /*
67 /*        defer_append() appends a record to the per-message defer log,
68 /*        with the dsn_text for delayed delivery to the named rcpt,
69 /*        updates the address verification service, or updates a message
70 /*        delivery record on request by the sender. The flags argument
71 /*        determines the action.
72 /*        The result is a convenient non-zero value.
73 /*        When the fast flush cache is enabled, the fast flush server is
74 /*        notified of deferred mail.
75 /*
76 /*        defer_flush() bounces the specified message to the specified
77 /*        sender, including the defer log that was built with defer_append().
78 /*        defer_flush() requests that the deferred recipients are deleted
79 /*        from the original queue file; the defer logfile is deleted after
80 /*        successful completion.
81 /*        The result is zero in case of success, non-zero otherwise.
82 /*
83 /*        defer_warn() sends a warning message that the mail in
84 /*        question has been deferred.  The defer log is not deleted,
85 /*        and no recipients are deleted from the original queue file.
86 /*
87 /*        defer_one() implements dsn_filter(3) compatibility for the
88 /*        bounce_one() routine.
89 /*
90 /*        defer_append_intern() is for use after the DSN filter.
91 /*
92 /*        Arguments:
93 /* .IP flags
94 /*        The bit-wise OR of zero or more of the following (specify
95 /*        BOUNCE_FLAG_NONE to explicitly request not special processing):
96 /* .RS
97 /* .IP BOUNCE_FLAG_CLEAN
98 /*        Delete the defer log in case of an error (as in: pretend
99 /*        that we never even tried to defer this message).
100 /* .IP BOUNCE_FLAG_DELRCPT
101 /*        When specified with a flush request, request that
102 /*        recipients be deleted from the queue file.
103 /*
104 /*        Note: the bounce daemon ignores this request when the
105 /*        recipient queue file offset is <= 0.
106 /* .IP DEL_REQ_FLAG_MTA_VRFY
107 /*        The message is an MTA-requested address verification probe.
108 /*        Update the address verification database instead of deferring
109 /*        mail.
110 /* .IP DEL_REQ_FLAG_USR_VRFY
111 /*        The message is a user-requested address expansion probe.
112 /*        Update the message delivery record instead of deferring
113 /*        mail.
114 /* .IP DEL_REQ_FLAG_RECORD
115 /*        This is a normal message with logged delivery. Update the
116 /*        message delivery record and defer mail delivery.
117 /* .RE
118 /* .IP queue
119 /*        The message queue name of the original message file.
120 /* .IP id
121 /*        The queue id of the original message file.
122 /* .IP stats
123 /*        Time stamps from different message delivery stages
124 /*        and session reuse count.
125 /* .IP rcpt
126 /*        Recipient information. See recipient_list(3).
127 /* .IP relay
128 /*        Host we could not talk to.
129 /* .IP dsn
130 /*        Delivery status. See dsn(3). The specified action is ignored.
131 /* .IP encoding
132 /*        The body content encoding: MAIL_ATTR_ENC_{7BIT,8BIT,NONE}.
133 /* .IP sendopts
134 /*        Sender-requested SMTPUTF8 or RequireTLS support.
135 /* .IP sender
136 /*        The sender envelope address.
137 /* .IP dsn_envid
138 /*        Optional DSN envelope ID.
139 /* .IP dsn_ret
140 /*        Optional DSN return full/headers option.
141 /* .PP
142 /*        For convenience, these functions always return a non-zero result.
143 /* DIAGNOSTICS
144 /*        Warnings: problems connecting to the defer service.
145 /*        Fatal: out of memory.
146 /* BUGS
147 /*        Should be replaced by routines with an attribute-value based
148 /*        interface instead of an interface that uses a rigid argument list.
149 /* LICENSE
150 /* .ad
151 /* .fi
152 /*        The Secure Mailer license must be distributed with this software.
153 /* AUTHOR(S)
154 /*        Wietse Venema
155 /*        IBM T.J. Watson Research
156 /*        P.O. Box 704
157 /*        Yorktown Heights, NY 10598, USA
158 /*
159 /*        Wietse Venema
160 /*        Google, Inc.
161 /*        111 8th Avenue
162 /*        New York, NY 10011, USA
163 /*
164 /*        Wietse Venema
165 /*        porcupine.org
166 /*--*/
167 
168 /* System library. */
169 
170 #include <sys_defs.h>
171 #include <string.h>
172 
173 /* Utility library. */
174 
175 #include <msg.h>
176 #include <vstring.h>
177 
178 /* Global library. */
179 
180 #define DSN_INTERN
181 #include <mail_params.h>
182 #include <mail_queue.h>
183 #include <mail_proto.h>
184 #include <flush_clnt.h>
185 #include <verify.h>
186 #include <dsn_util.h>
187 #include <rcpt_print.h>
188 #include <dsn_print.h>
189 #include <log_adhoc.h>
190 #include <trace.h>
191 #include <defer.h>
192 
193 #define STR(x)      vstring_str(x)
194 
195 /* defer_append - defer message delivery */
196 
defer_append(int flags,const char * id,MSG_STATS * stats,RECIPIENT * rcpt,const char * relay,DSN * dsn)197 int     defer_append(int flags, const char *id, MSG_STATS *stats,
198                                  RECIPIENT *rcpt, const char *relay,
199                                  DSN *dsn)
200 {
201     DSN     my_dsn = *dsn;
202     DSN    *dsn_res;
203 
204     /*
205      * Sanity check.
206      */
207     if (my_dsn.status[0] != '4' || !dsn_valid(my_dsn.status)) {
208           msg_warn("defer_append: ignoring dsn code \"%s\"", my_dsn.status);
209           my_dsn.status = "4.0.0";
210     }
211 
212     /*
213      * DSN filter (Postfix 3.0).
214      */
215     if (delivery_status_filter != 0
216     && (dsn_res = dsn_filter_lookup(delivery_status_filter, &my_dsn)) != 0) {
217           if (dsn_res->status[0] == '5')
218               return (bounce_append_intern(flags, id, stats, rcpt, relay, dsn_res));
219           my_dsn = *dsn_res;
220     }
221     return (defer_append_intern(flags, id, stats, rcpt, relay, &my_dsn));
222 }
223 
224 /* defer_append_intern - defer message delivery */
225 
defer_append_intern(int flags,const char * id,MSG_STATS * stats,RECIPIENT * rcpt,const char * relay,DSN * dsn)226 int     defer_append_intern(int flags, const char *id, MSG_STATS *stats,
227                                           RECIPIENT *rcpt, const char *relay,
228                                           DSN *dsn)
229 {
230     const char *rcpt_domain;
231     DSN     my_dsn = *dsn;
232     int     status;
233 
234     /*
235      * MTA-requested address verification information is stored in the verify
236      * service database.
237      */
238     if (flags & DEL_REQ_FLAG_MTA_VRFY) {
239           my_dsn.action = "undeliverable";
240           status = verify_append(id, stats, rcpt, relay, &my_dsn,
241                                      DEL_RCPT_STAT_DEFER);
242           return (status);
243     }
244 
245     /*
246      * User-requested address verification information is logged and mailed
247      * to the requesting user.
248      */
249     if (flags & DEL_REQ_FLAG_USR_VRFY) {
250           my_dsn.action = "undeliverable";
251           status = trace_append(flags, id, stats, rcpt, relay, &my_dsn);
252           return (status);
253     }
254 
255     /*
256      * Normal mail delivery. May also send a delivery record to the user.
257      *
258      * XXX DSN We write all deferred recipients to the defer logfile regardless
259      * of DSN NOTIFY options, because those options don't apply to mailq(1)
260      * reports or to postmaster notifications.
261      */
262     else {
263 
264           /*
265            * Supply default action.
266            */
267           my_dsn.action = "delayed";
268 
269           if (mail_command_client(MAIL_CLASS_PRIVATE, var_defer_service,
270                                         MAIL_ATTR_PROTO_BOUNCE,
271                                  SEND_ATTR_INT(MAIL_ATTR_NREQ, BOUNCE_CMD_APPEND),
272                                         SEND_ATTR_INT(MAIL_ATTR_FLAGS, flags),
273                                         SEND_ATTR_STR(MAIL_ATTR_QUEUEID, id),
274                                   SEND_ATTR_FUNC(rcpt_print, (const void *) rcpt),
275                                 SEND_ATTR_FUNC(dsn_print, (const void *) &my_dsn),
276                                         ATTR_TYPE_END) != 0)
277               msg_warn("%s: %s service failure", id, var_defer_service);
278           log_adhoc(id, stats, rcpt, relay, &my_dsn, "deferred");
279 
280           /*
281            * Traced delivery.
282            */
283           if (flags & DEL_REQ_FLAG_RECORD)
284               if (trace_append(flags, id, stats, rcpt, relay, &my_dsn) != 0)
285                     msg_warn("%s: %s service failure", id, var_trace_service);
286 
287           /*
288            * Notify the fast flush service. XXX Should not this belong in the
289            * bounce/defer daemon? Well, doing it here is more robust.
290            */
291           if ((rcpt_domain = strrchr(rcpt->address, '@')) != 0
292               && *++rcpt_domain != 0)
293               switch (flush_add(rcpt_domain, id)) {
294               case FLUSH_STAT_OK:
295               case FLUSH_STAT_DENY:
296                     break;
297               default:
298                     msg_warn("%s: %s service failure", id, var_flush_service);
299                     break;
300               }
301           return (-1);
302     }
303 }
304 
305 /* defer_flush - flush the defer log and deliver to the sender */
306 
defer_flush(int flags,const char * queue,const char * id,const char * encoding,int sendopts,const char * sender,const char * dsn_envid,int dsn_ret)307 int     defer_flush(int flags, const char *queue, const char *id,
308                                 const char *encoding, int sendopts,
309                                 const char *sender, const char *dsn_envid,
310                                 int dsn_ret)
311 {
312     flags |= BOUNCE_FLAG_DELRCPT;
313 
314     if (mail_command_client(MAIL_CLASS_PRIVATE, var_defer_service,
315                                   MAIL_ATTR_PROTO_BOUNCE,
316                                   SEND_ATTR_INT(MAIL_ATTR_NREQ, BOUNCE_CMD_FLUSH),
317                                   SEND_ATTR_INT(MAIL_ATTR_FLAGS, flags),
318                                   SEND_ATTR_STR(MAIL_ATTR_QUEUE, queue),
319                                   SEND_ATTR_STR(MAIL_ATTR_QUEUEID, id),
320                                   SEND_ATTR_STR(MAIL_ATTR_ENCODING, encoding),
321                                   SEND_ATTR_INT(MAIL_ATTR_SENDOPTS, sendopts),
322                                   SEND_ATTR_STR(MAIL_ATTR_SENDER, sender),
323                                   SEND_ATTR_STR(MAIL_ATTR_DSN_ENVID, dsn_envid),
324                                   SEND_ATTR_INT(MAIL_ATTR_DSN_RET, dsn_ret),
325                                   ATTR_TYPE_END) == 0) {
326           return (0);
327     } else {
328           return (-1);
329     }
330 }
331 
332 /* defer_warn - send a copy of the defer log to the sender as a warning bounce
333  * do not flush the log */
334 
defer_warn(int flags,const char * queue,const char * id,const char * encoding,int sendopts,const char * sender,const char * envid,int dsn_ret)335 int     defer_warn(int flags, const char *queue, const char *id,
336                                const char *encoding, int sendopts,
337                              const char *sender, const char *envid, int dsn_ret)
338 {
339     if (mail_command_client(MAIL_CLASS_PRIVATE, var_defer_service,
340                                   MAIL_ATTR_PROTO_BOUNCE,
341                                   SEND_ATTR_INT(MAIL_ATTR_NREQ, BOUNCE_CMD_WARN),
342                                   SEND_ATTR_INT(MAIL_ATTR_FLAGS, flags),
343                                   SEND_ATTR_STR(MAIL_ATTR_QUEUE, queue),
344                                   SEND_ATTR_STR(MAIL_ATTR_QUEUEID, id),
345                                   SEND_ATTR_STR(MAIL_ATTR_ENCODING, encoding),
346                                   SEND_ATTR_INT(MAIL_ATTR_SENDOPTS, sendopts),
347                                   SEND_ATTR_STR(MAIL_ATTR_SENDER, sender),
348                                   SEND_ATTR_STR(MAIL_ATTR_DSN_ENVID, envid),
349                                   SEND_ATTR_INT(MAIL_ATTR_DSN_RET, dsn_ret),
350                                   ATTR_TYPE_END) == 0) {
351           return (0);
352     } else {
353           return (-1);
354     }
355 }
356 
357 /* defer_one - defer mail for one recipient */
358 
defer_one(int flags,const char * queue,const char * id,const char * encoding,int sendopts,const char * sender,const char * dsn_envid,int dsn_ret,MSG_STATS * stats,RECIPIENT * rcpt,const char * relay,DSN * dsn)359 int     defer_one(int flags, const char *queue, const char *id,
360                               const char *encoding, int sendopts,
361                               const char *sender, const char *dsn_envid,
362                               int dsn_ret, MSG_STATS *stats, RECIPIENT *rcpt,
363                               const char *relay, DSN *dsn)
364 {
365     DSN     my_dsn = *dsn;
366     DSN    *dsn_res;
367 
368     /*
369      * Sanity check.
370      */
371     if (my_dsn.status[0] != '4' || !dsn_valid(my_dsn.status)) {
372           msg_warn("defer_one: ignoring dsn code \"%s\"", my_dsn.status);
373           my_dsn.status = "4.0.0";
374     }
375 
376     /*
377      * DSN filter (Postfix 3.0).
378      */
379     if (delivery_status_filter != 0
380     && (dsn_res = dsn_filter_lookup(delivery_status_filter, &my_dsn)) != 0) {
381           if (dsn_res->status[0] == '5')
382               return (bounce_one_intern(flags, queue, id, encoding, sendopts,
383                                               sender, dsn_envid, dsn_ret, stats,
384                                               rcpt, relay, dsn_res));
385           my_dsn = *dsn_res;
386     }
387     return (defer_append_intern(flags, id, stats, rcpt, relay, &my_dsn));
388 }
389