1 /* $NetBSD: bounce_warn_service.c,v 1.4 2026/05/09 18:49:15 christos Exp $ */ 2 3 /*++ 4 /* NAME 5 /* bounce_warn_service 3 6 /* SUMMARY 7 /* send non-delivery report to sender, server side 8 /* SYNOPSIS 9 /* #include "bounce_service.h" 10 /* 11 /* int bounce_warn_service(flags, service, queue_name, queue_id, 12 /* encoding, sendopts, sender, envid, 13 /* dsn_ret, templates) 14 /* int flags; 15 /* char *service; 16 /* char *queue_name; 17 /* char *queue_id; 18 /* char *encoding; 19 /* int sendopts; 20 /* char *sender; 21 /* char *envid; 22 /* int dsn_ret; 23 /* BOUNCE_TEMPLATES *ts; 24 /* DESCRIPTION 25 /* This module implements the server side of the bounce_warn() 26 /* (send delay notice) request. The logfile 27 /* is not removed, and a warning is sent instead of a bounce. 28 /* 29 /* When a message bounces, a full copy is sent to the originator, 30 /* and an optional copy of the diagnostics with message headers is 31 /* sent to the postmaster. The result is non-zero when the operation 32 /* should be tried again. 33 /* 34 /* When a bounce is sent, the sender address is the empty 35 /* address. When a bounce bounces, an optional double bounce 36 /* with the entire undeliverable mail is sent to the postmaster, 37 /* with as sender address the double bounce address. 38 /* DIAGNOSTICS 39 /* Fatal error: error opening existing file. 40 /* BUGS 41 /* SEE ALSO 42 /* bounce(3) basic bounce service client interface 43 /* LICENSE 44 /* .ad 45 /* .fi 46 /* The Secure Mailer license must be distributed with this software. 47 /* AUTHOR(S) 48 /* Wietse Venema 49 /* IBM T.J. Watson Research 50 /* P.O. Box 704 51 /* Yorktown Heights, NY 10598, USA 52 /*--*/ 53 54 /* System library. */ 55 56 #include <sys_defs.h> 57 #include <fcntl.h> 58 #include <errno.h> 59 #include <string.h> 60 #include <ctype.h> 61 62 /* Utility library. */ 63 64 #include <msg.h> 65 #include <vstream.h> 66 #include <name_mask.h> 67 #include <stringops.h> 68 69 /* Global library. */ 70 71 #include <mail_params.h> 72 #include <mail_queue.h> 73 #include <post_mail.h> 74 #include <mail_addr.h> 75 #include <mail_error.h> 76 #include <dsn_mask.h> 77 #include <rec_type.h> 78 79 /* Application-specific. */ 80 81 #include "bounce_service.h" 82 83 #define STR vstring_str 84 85 /* bounce_warn_service - send a delayed mail notice */ 86 87 int bounce_warn_service(int unused_flags, char *service, char *queue_name, 88 char *queue_id, char *encoding, 89 int sendopts, char *recipient, 90 char *dsn_envid, int dsn_ret, 91 BOUNCE_TEMPLATES *ts) 92 { 93 BOUNCE_INFO *bounce_info; 94 int bounce_status = 1; 95 int postmaster_status = 1; 96 VSTREAM *bounce; 97 int notify_mask = name_mask(VAR_NOTIFY_CLASSES, mail_error_masks, 98 var_notify_classes); 99 VSTRING *new_id = vstring_alloc(10); 100 char *postmaster; 101 int count; 102 103 /* 104 * Initialize. Open queue file, bounce log, etc. 105 * 106 * XXX DSN This service produces RFC 3464-style "delayed mail" reports from 107 * information in the defer logfile. That same file is used for three 108 * different types of report: 109 * 110 * a) On-demand reports of all delayed deliveries by the mailq(1) command. 111 * This reports all recipients that have a transient delivery error. 112 * 113 * b) RFC 3464-style "delayed mail" notifications by the defer(8) service. 114 * This reports to the sender all recipients that have no DSN NOTIFY 115 * information (compatibility) and all recipients that have DSN 116 * NOTIFY=DELAY; this reports to postmaster all recipients, subject to 117 * notify_classes restrictions. 118 * 119 * c) RFC 3464-style bounce reports by the bounce(8) service when mail is 120 * too old. This reports to the sender all recipients that have no DSN 121 * NOTIFY information (compatibility) and all recipients that have DSN 122 * NOTIFY=FAILURE; this reports to postmaster all recipients, subject to 123 * notify_classes restrictions. 124 */ 125 bounce_info = bounce_mail_init(service, queue_name, queue_id, 126 encoding, sendopts, dsn_envid, ts->delay); 127 128 #define NULL_SENDER MAIL_ADDR_EMPTY /* special address */ 129 #define NULL_TRACE_FLAGS 0 130 131 /* 132 * The choice of sender address depends on the recipient address. For a 133 * single bounce (a non-delivery notification to the message originator), 134 * the sender address is the empty string. For a double bounce (typically 135 * a failed single bounce, or a postmaster notification that was produced 136 * by any of the mail processes) the sender address is defined by the 137 * var_double_bounce_sender configuration variable. When a double bounce 138 * cannot be delivered, the queue manager blackholes the resulting triple 139 * bounce message. 140 */ 141 142 /* 143 * Double bounce failed. Never send a triple bounce. 144 * 145 * However, this does not prevent double bounces from bouncing on other 146 * systems. In order to cope with this, either the queue manager must 147 * recognize the double-bounce recipient address and discard mail, or 148 * every delivery agent must recognize the double-bounce sender address 149 * and substitute something else so mail does not come back at us. 150 */ 151 if (strcasecmp_utf8(recipient, mail_addr_double_bounce()) == 0) { 152 msg_warn("%s: undeliverable postmaster notification discarded", 153 queue_id); 154 bounce_status = 0; 155 } 156 157 /* 158 * Single bounce failed. Optionally send a double bounce to postmaster, 159 * subject to notify_classes restrictions. 160 */ 161 #define ANY_BOUNCE (MAIL_ERROR_2BOUNCE | MAIL_ERROR_BOUNCE) 162 #define SEND_POSTMASTER_DELAY_NOTICE (notify_mask & MAIL_ERROR_DELAY) 163 164 else if (*recipient == 0) { 165 if (!SEND_POSTMASTER_DELAY_NOTICE) { 166 bounce_status = 0; 167 } else { 168 postmaster = var_delay_rcpt; 169 if ((bounce = post_mail_fopen_nowait(mail_addr_double_bounce(), 170 postmaster, 171 MAIL_SRC_MASK_BOUNCE, 172 NULL_TRACE_FLAGS, 173 sendopts, 174 new_id)) != 0) { 175 176 /* 177 * Double bounce to Postmaster. This is the last opportunity 178 * for this message to be delivered. Send the text with 179 * reason for the bounce, and the headers of the original 180 * message. Don't bother sending the boiler-plate text. 181 */ 182 msg_info("%s: postmaster delay notification: %s", 183 queue_id, STR(new_id)); 184 count = -1; 185 if (!bounce_header(bounce, bounce_info, postmaster, 186 POSTMASTER_COPY) 187 && (count = bounce_diagnostic_log(bounce, bounce_info, 188 DSN_NOTIFY_OVERRIDE)) > 0 189 && bounce_header_dsn(bounce, bounce_info) == 0 190 && bounce_diagnostic_dsn(bounce, bounce_info, 191 DSN_NOTIFY_OVERRIDE) > 0) { 192 bounce_original(bounce, bounce_info, DSN_RET_FULL); 193 bounce_status = post_mail_fclose(bounce); 194 if (bounce_status) 195 msg_warn("%s: postmaster notification failed: %s", 196 queue_id, cleanup_strerror(bounce_status)); 197 } else { 198 (void) vstream_fclose(bounce); 199 if (count == 0) 200 bounce_status = 0; 201 } 202 } else { 203 msg_warn("%s: postmaster notification failed", queue_id); 204 } 205 } 206 } 207 208 /* 209 * Non-bounce failed. Send a single bounce, subject to DSN NOTIFY 210 * restrictions. 211 */ 212 else { 213 if ((bounce = post_mail_fopen_nowait(NULL_SENDER, recipient, 214 MAIL_SRC_MASK_BOUNCE, 215 NULL_TRACE_FLAGS, 216 sendopts, 217 new_id)) != 0) { 218 219 /* 220 * Send the bounce message header, some boilerplate text that 221 * pretends that we are a polite mail system, the text with 222 * reason for the bounce, and a copy of the original message. 223 */ 224 msg_info("%s: sender delay notification: %s", 225 queue_id, STR(new_id)); 226 count = -1; 227 if (bounce_header(bounce, bounce_info, recipient, 228 NO_POSTMASTER_COPY) == 0 229 && bounce_boilerplate(bounce, bounce_info) == 0 230 && (count = bounce_diagnostic_log(bounce, bounce_info, 231 DSN_NOTIFY_DELAY)) > 0 232 && bounce_header_dsn(bounce, bounce_info) == 0 233 && bounce_diagnostic_dsn(bounce, bounce_info, 234 DSN_NOTIFY_DELAY) > 0) { 235 bounce_original(bounce, bounce_info, DSN_RET_HDRS); 236 bounce_status = post_mail_fclose(bounce); 237 if (bounce_status) 238 msg_warn("%s: sender notification failed to %s: %s", 239 queue_id, recipient, 240 cleanup_strerror(bounce_status)); 241 } else { 242 (void) vstream_fclose(bounce); 243 if (count == 0) 244 bounce_status = 0; 245 } 246 } else { 247 msg_warn("%s: sender notification failed to %s", 248 queue_id, recipient); 249 } 250 251 /* 252 * Optionally send a postmaster notice, subject to notify_classes 253 * restrictions. 254 * 255 * This postmaster notice is not critical, so if it fails don't 256 * retransmit the bounce that we just generated, just log a warning. 257 */ 258 if (bounce_status == 0 && SEND_POSTMASTER_DELAY_NOTICE 259 && strcasecmp_utf8(recipient, mail_addr_double_bounce()) != 0) { 260 261 /* 262 * Send the text with reason for the bounce, and the headers of 263 * the original message. Don't bother sending the boiler-plate 264 * text. This postmaster notice is not critical, so if it fails 265 * don't retransmit the bounce that we just generated, just log a 266 * warning. 267 */ 268 postmaster = var_delay_rcpt; 269 if ((bounce = post_mail_fopen_nowait(mail_addr_double_bounce(), 270 postmaster, 271 MAIL_SRC_MASK_BOUNCE, 272 NULL_TRACE_FLAGS, 273 sendopts, 274 new_id)) != 0) { 275 msg_info("%s: postmaster delay notification: %s", 276 queue_id, STR(new_id)); 277 count = -1; 278 if (bounce_header(bounce, bounce_info, postmaster, 279 POSTMASTER_COPY) == 0 280 && (count = bounce_diagnostic_log(bounce, bounce_info, 281 DSN_NOTIFY_OVERRIDE)) > 0 282 && bounce_header_dsn(bounce, bounce_info) == 0 283 && bounce_diagnostic_dsn(bounce, bounce_info, 284 DSN_NOTIFY_OVERRIDE) > 0) { 285 bounce_original(bounce, bounce_info, DSN_RET_HDRS); 286 postmaster_status = post_mail_fclose(bounce); 287 } else { 288 (void) vstream_fclose(bounce); 289 if (count == 0) 290 postmaster_status = 0; 291 } 292 } 293 if (postmaster_status) 294 msg_warn("%s: postmaster notice failed while warning %s", 295 queue_id, recipient); 296 } 297 } 298 299 /* 300 * Cleanup. 301 */ 302 bounce_mail_free(bounce_info); 303 vstring_free(new_id); 304 305 return (bounce_status); 306 } 307
Indexes created Wed Aug 12 00:25:48 UTC 2026