1 // Transmit outbound SMTP mail to the big wide world of the Internet
3 // This is the new, exciting, clever version that makes libcurl do all the work :)
5 // Copyright (c) 1997-2023 by the citadel.org team
7 // This program is open source software. Use, duplication, or disclosure
8 // is subject to the terms of the GNU General Public License, version 3.
17 #include <sys/types.h>
19 #include <libcitadel.h>
20 #include <curl/curl.h>
21 #include "../../sysconfig.h"
22 #include "../../citadel.h"
23 #include "../../server.h"
24 #include "../../citserver.h"
25 #include "../../support.h"
26 #include "../../config.h"
27 #include "../../ctdl_module.h"
28 #include "../../clientsocket.h"
29 #include "../../msgbase.h"
30 #include "../../domain.h"
31 #include "../../internet_addressing.h"
32 #include "../../citadel_dirs.h"
33 #include "../smtp/smtp_util.h"
35 struct smtpmsgsrc { // Data passed in and out of libcurl for message upload
41 // Initialize the SMTP outbound queue
42 void smtp_init_spoolout(void) {
43 struct ctdlroom qrbuf;
45 // Create the room. This will silently fail if the room already
46 // exists, and that's perfectly ok, because we want it to exist.
47 CtdlCreateRoom(SMTP_SPOOLOUT_ROOM, 3, "", 0, 1, 0, VIEW_QUEUE);
49 // Make sure it's set to be a "system room" so it doesn't show up
50 // in the <K>nown rooms list for administrators.
51 if (CtdlGetRoomLock(&qrbuf, SMTP_SPOOLOUT_ROOM) == 0) {
52 qrbuf.QRflags2 |= QR2_SYSTEM;
53 CtdlPutRoomLock(&qrbuf);
58 // For internet mail, generate delivery instructions.
59 // Yes, this is recursive. Deal with it. Infinite recursion does
60 // not happen because the delivery instructions message does not
61 // contain a recipient.
62 int smtp_aftersave(struct CtdlMessage *msg, struct recptypes *recps) {
63 if ((recps != NULL) && (recps->num_internet > 0)) {
64 struct CtdlMessage *imsg = NULL;
66 StrBuf *SpoolMsg = NewStrBuf();
70 syslog(LOG_DEBUG, "smtpclient: generating delivery instructions");
72 StrBufPrintf(SpoolMsg,
73 "Content-type: " SPOOLMIME "\n"
76 "submitted|%ld\n" "bounceto|%s\n", msg->cm_fields[eVltMsgNum], (long) time(NULL), recps->bounce_to);
78 if (recps->envelope_from != NULL) {
79 StrBufAppendBufPlain(SpoolMsg, HKEY("envelope_from|"), 0);
80 StrBufAppendBufPlain(SpoolMsg, recps->envelope_from, -1, 0);
81 StrBufAppendBufPlain(SpoolMsg, HKEY("\n"), 0);
83 if (recps->sending_room != NULL) {
84 StrBufAppendBufPlain(SpoolMsg, HKEY("source_room|"), 0);
85 StrBufAppendBufPlain(SpoolMsg, recps->sending_room, -1, 0);
86 StrBufAppendBufPlain(SpoolMsg, HKEY("\n"), 0);
89 nTokens = num_tokens(recps->recp_internet, '|');
90 for (i = 0; i < nTokens; i++) {
92 len = extract_token(recipient, recps->recp_internet, i, '|', sizeof recipient);
94 StrBufAppendBufPlain(SpoolMsg, HKEY("remote|"), 0);
95 StrBufAppendBufPlain(SpoolMsg, recipient, len, 0);
96 StrBufAppendBufPlain(SpoolMsg, HKEY("|0||\n"), 0);
100 imsg = malloc(sizeof(struct CtdlMessage));
101 memset(imsg, 0, sizeof(struct CtdlMessage));
102 imsg->cm_magic = CTDLMESSAGE_MAGIC;
103 imsg->cm_anon_type = MES_NORMAL;
104 imsg->cm_format_type = FMT_RFC822;
105 CM_SetField(imsg, eMsgSubject, HKEY("QMSG"));
106 CM_SetField(imsg, eAuthor, HKEY("Citadel"));
107 CM_SetField(imsg, eJournal, HKEY("do not journal"));
108 CM_SetAsFieldSB(imsg, eMesageText, &SpoolMsg);
109 CtdlSubmitMsg(imsg, NULL, SMTP_SPOOLOUT_ROOM);
116 // Callback for smtp_attempt_delivery() to supply libcurl with upload data.
117 static size_t upload_source(void *ptr, size_t size, size_t nmemb, void *userp) {
118 struct smtpmsgsrc *s = (struct smtpmsgsrc *) userp;
120 const char *send_this = NULL;
122 sendbytes = (size * nmemb);
124 if (s->bytes_sent >= s->bytes_total) {
125 return (0); // no data remaining; we are done
128 if (sendbytes > (s->bytes_total - s->bytes_sent)) {
129 sendbytes = s->bytes_total - s->bytes_sent; // can't send more than we have
132 send_this = ChrPtr(s->TheMessage);
133 send_this += s->bytes_sent; // start where we last left off
135 memcpy(ptr, send_this, sendbytes);
136 s->bytes_sent += sendbytes;
137 return(sendbytes); // return the number of bytes _actually_ copied
141 // The libcurl API doesn't provide a way to capture the actual SMTP result message returned
142 // by the remote server. This is an ugly way to extract it, by capturing debug data from
143 // the library and filtering on the lines we want.
144 int ctdl_libcurl_smtp_debug_callback(CURL *handle, curl_infotype type, char *data, size_t size, void *userptr) {
145 if (type != CURLINFO_HEADER_IN)
149 char *debugbuf = (char *) userptr;
151 int len = strlen(debugbuf);
152 if (len + size > SIZ)
155 memcpy(&debugbuf[len], data, size);
156 debugbuf[len + size] = 0;
161 // Go through the debug output of an SMTP transaction, and boil it down to just the final success or error response message.
162 void trim_response(long response_code, char *response) {
163 if ((response_code < 100) || (response_code > 999) || (IsEmptyStr(response))) {
167 char *t = malloc(strlen(response));
174 for (p = response; *p != 0; ++p) {
175 if ( (*p != '\n') && (!isprint(*p)) ) { // expunge any nonprintables except for newlines
180 char response_code_str[4];
181 snprintf(response_code_str, sizeof response_code_str, "%ld", response_code);
182 char *respstart = strstr(response, response_code_str);
183 if (respstart == NULL) { // If we have a response code but no response text,
184 strcpy(response, smtpstatus(response_code)); // use one of our canned messages.
187 strcpy(response, respstart);
189 p = strstr(response, "\n");
196 // Attempt a delivery to one recipient.
197 // Returns a three-digit SMTP status code.
198 int smtp_attempt_delivery(long msgid, char *recp, char *envelope_from, char *source_room, char *response) {
200 char *fromaddr = NULL;
202 CURLcode res = CURLE_OK;
203 struct curl_slist *recipients = NULL;
204 long response_code = 421;
210 char try_this_mx[256];
214 syslog(LOG_DEBUG, "smtpclient: smtp_attempt_delivery(%ld, %s)", msgid, recp);
216 process_rfc822_addr(recp, user, node, name); // split recipient address into username, hostname, displayname
217 num_mx = getmx(mxes, node);
222 CC->redirect_buffer = NewStrBufPlain(NULL, SIZ);
223 if (!IsEmptyStr(source_room)) {
224 // If we have a source room, it's probably a mailing list message; generate an unsubscribe header
225 char esc_room[ROOMNAMELEN*2];
226 char esc_email[1024];
227 urlesc(esc_room, sizeof esc_room, source_room);
228 urlesc(esc_email, sizeof esc_email, recp);
229 cprintf("List-Unsubscribe: <http://%s/listsub?cmd=unsubscribe&room=%s&email=%s>\r\n",
230 CtdlGetConfigStr("c_fqdn"),
235 CtdlOutputMsg(msgid, MT_RFC822, HEADERS_ALL, 0, 1, NULL, 0, NULL, &fromaddr, NULL);
236 s.TheMessage = CC->redirect_buffer;
237 s.bytes_total = StrLength(CC->redirect_buffer);
239 CC->redirect_buffer = NULL;
241 // keep trying MXes until one works or we run out
242 for (i = 0; ((i < num_mx) && ((response_code / 100) == 4)); ++i) {
243 response_code = 421; // default 421 makes non-protocol errors transient
244 s.bytes_sent = 0; // rewind our buffer in case we try multiple MXes
246 curl = curl_easy_init();
250 if (!IsEmptyStr(envelope_from)) {
251 curl_easy_setopt(curl, CURLOPT_MAIL_FROM, envelope_from);
254 curl_easy_setopt(curl, CURLOPT_MAIL_FROM, fromaddr);
257 recipients = curl_slist_append(recipients, recp);
258 curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
259 curl_easy_setopt(curl, CURLOPT_READFUNCTION, upload_source);
260 curl_easy_setopt(curl, CURLOPT_READDATA, &s);
261 curl_easy_setopt(curl, CURLOPT_UPLOAD, 1); // tell libcurl we are uploading
262 curl_easy_setopt(curl, CURLOPT_TIMEOUT, 20L); // Time out after 20 seconds
263 if (CtdlGetConfigInt("c_smtpclient_disable_starttls") == 0) {
264 curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_TRY); // Attempt STARTTLS if offered
266 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
267 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
268 curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, ctdl_libcurl_smtp_debug_callback);
269 curl_easy_setopt(curl, CURLOPT_DEBUGDATA, (void *) response);
270 curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
272 // Construct an SMTP URL in the form of:
273 // smtp[s]://target_host/source_host
274 // This looks weird but libcurl uses that last part to set our name for EHLO or HELO.
275 // We check for "smtp://" and "smtps://" because the admin may have put those prefixes in a smart-host entry.
276 // If there is no prefix we add "smtp://"
277 extract_token(try_this_mx, mxes, i, '|', (sizeof try_this_mx - 7));
278 snprintf(smtp_url, sizeof smtp_url,
280 (((!strncasecmp(try_this_mx, HKEY("smtp://")))
281 || (!strncasecmp(try_this_mx, HKEY("smtps://")))) ? "" : "smtp://"),
282 try_this_mx, CtdlGetConfigStr("c_fqdn")
284 curl_easy_setopt(curl, CURLOPT_URL, smtp_url);
285 syslog(LOG_DEBUG, "smtpclient: trying MX %d of %d <%s>", i+1, num_mx, smtp_url); // send the message
286 res = curl_easy_perform(curl);
287 curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &response_code);
289 "smtpclient: libcurl returned %d (%s) , SMTP response %ld",
290 res, curl_easy_strerror(res), response_code
293 if ((res != CURLE_OK) && (response_code == 0)) { // check for errors
297 curl_slist_free_all(recipients);
298 recipients = NULL; // this gets reused; avoid double-free
299 curl_easy_cleanup(curl);
300 curl = NULL; // this gets reused; avoid double-free
302 // Trim the error message buffer down to just the actual message
303 trim_response(response_code, response);
307 FreeStrBuf(&s.TheMessage);
311 return ((int) response_code);
315 // Process one outbound message.
316 void smtp_process_one_msg(long qmsgnum) {
317 struct CtdlMessage *msg = NULL;
324 int delete_this_queue = 0;
325 char server_response[SIZ];
327 msg = CtdlFetchMessage(qmsgnum, 1);
329 syslog(LOG_WARNING, "smtpclient: %ld does not exist", qmsgnum);
333 instr = msg->cm_fields[eMesageText];
334 msg->cm_fields[eMesageText] = NULL;
337 // if the queue message has any CRLF's convert them to LF's
339 while (crlf = strstr(instr, "\r\n"), crlf != NULL) {
340 strcpy(crlf, crlf + 1);
343 // Strip out the headers and we are now left with just the instructions.
344 char *soi = strstr(instr, "\n\n");
346 strcpy(instr, soi + 2);
350 time_t submitted = time(NULL);
351 time_t attempted = 0;
352 char *bounceto = NULL;
353 char *envelope_from = NULL;
354 char *source_room = NULL;
357 for (i = 0; i < num_tokens(instr, '\n'); ++i) {
358 extract_token(cfgline, instr, i, '\n', sizeof cfgline);
359 if (!strncasecmp(cfgline, HKEY("msgid|")))
360 msgid = atol(&cfgline[6]);
361 if (!strncasecmp(cfgline, HKEY("submitted|")))
362 submitted = atol(&cfgline[10]);
363 if (!strncasecmp(cfgline, HKEY("attempted|")))
364 attempted = atol(&cfgline[10]);
365 if (!strncasecmp(cfgline, HKEY("bounceto|")))
366 bounceto = strdup(&cfgline[9]);
367 if (!strncasecmp(cfgline, HKEY("envelope_from|")))
368 envelope_from = strdup(&cfgline[14]);
369 if (!strncasecmp(cfgline, HKEY("source_room|")))
370 source_room = strdup(&cfgline[12]);
373 int should_try_now = 0;
374 if (attempted < submitted) { // If no attempts have been made yet, try now
377 else if ((attempted - submitted) <= 14400) {
378 if ((time(NULL) - attempted) > 1800) { // First four hours, retry every 30 minutes
383 if ((time(NULL) - attempted) > 14400) { // After that, retry once every 4 hours
388 if (should_try_now) {
389 syslog(LOG_DEBUG, "smtpclient: attempting delivery of message <%ld> now", qmsgnum);
391 syslog(LOG_DEBUG, "smtpclient: this message originated in <%s>", source_room);
393 StrBuf *NewInstr = NewStrBuf();
394 StrBufAppendPrintf(NewInstr, "Content-type: " SPOOLMIME "\n\n");
395 StrBufAppendPrintf(NewInstr, "msgid|%ld\n", msgid);
396 StrBufAppendPrintf(NewInstr, "submitted|%ld\n", submitted);
398 StrBufAppendPrintf(NewInstr, "bounceto|%s\n", bounceto);
401 StrBufAppendPrintf(NewInstr, "envelope_from|%s\n", envelope_from);
403 for (i = 0; i < num_tokens(instr, '\n'); ++i) {
404 extract_token(cfgline, instr, i, '\n', sizeof cfgline);
405 if (!strncasecmp(cfgline, HKEY("remote|"))) {
407 int previous_result = extract_int(cfgline, 2);
408 if ((previous_result == 0) || (previous_result == 4)) {
409 int new_result = 421;
410 extract_token(recp, cfgline, 1, '|', sizeof recp);
411 new_result = smtp_attempt_delivery(msgid, recp, envelope_from, source_room, server_response);
412 syslog(LOG_DEBUG, "smtpclient: recp: <%s> , result: %d (%s)", recp, new_result, server_response);
413 if ((new_result / 100) == 2) {
417 if ((new_result / 100) == 5) {
423 StrBufAppendPrintf(NewInstr, "remote|%s|%ld|%ld (%s)\n", recp, (new_result / 100), new_result, server_response);
429 StrBufAppendPrintf(NewInstr, "attempted|%ld\n", time(NULL));
431 // All deliveries have now been attempted. Now determine the disposition of this queue entry.
433 time_t age = time(NULL) - submitted;
435 "smtpclient: submission age: %ldd%ldh%ldm%lds",
436 (age / 86400), ((age % 86400) / 3600), ((age % 3600) / 60), (age % 60));
437 syslog(LOG_DEBUG, "smtpclient: num_success=%d , num_fail=%d , num_delayed=%d", num_success, num_fail, num_delayed);
439 // If there are permanent fails on this attempt, deliver a bounce to the user.
440 // The 5XX fails will be recorded in the rewritten queue, but they will be removed before the next attempt.
442 smtp_do_bounce(ChrPtr(NewInstr), SDB_BOUNCE_FATALS);
444 // If all deliveries have either succeeded or failed, we are finished with this queue entry.
445 if (num_delayed == 0) {
446 delete_this_queue = 1;
448 // If it's been more than five days, give up and tell the sender that delivery failed
449 else if ((time(NULL) - submitted) > SMTP_DELIVER_FAIL) {
450 smtp_do_bounce(ChrPtr(NewInstr), SDB_BOUNCE_ALL);
451 delete_this_queue = 1;
453 // If it's been more than four hours but less than five days, warn the sender that delivery is delayed
454 else if (((attempted - submitted) < SMTP_DELIVER_WARN) && ((time(NULL) - submitted) >= SMTP_DELIVER_WARN)) {
455 smtp_do_bounce(ChrPtr(NewInstr), SDB_WARN);
458 if (delete_this_queue) {
459 syslog(LOG_DEBUG, "smtpclient: %ld deleting", qmsgnum);
460 deletes[0] = qmsgnum;
462 CtdlDeleteMessages(SMTP_SPOOLOUT_ROOM, deletes, 2, "");
463 FreeStrBuf(&NewInstr); // We have to free NewInstr here, no longer needed
466 // replace the old queue entry with the new one
467 syslog(LOG_DEBUG, "smtpclient: %ld rewriting", qmsgnum);
468 msg = convert_internet_message_buf(&NewInstr); // This function will free NewInstr for us
469 CtdlSubmitMsg(msg, NULL, SMTP_SPOOLOUT_ROOM);
471 CtdlDeleteMessages(SMTP_SPOOLOUT_ROOM, &qmsgnum, 1, "");
475 syslog(LOG_DEBUG, "smtpclient: %ld retry time not reached", qmsgnum);
478 if (bounceto != NULL) {
481 if (envelope_from != NULL) {
484 if (source_room != NULL) {
491 // Callback for smtp_do_queue()
492 void smtp_add_msg(long msgnum, void *userdata) {
493 Array *smtp_queue = (Array *) userdata;
494 array_append(smtp_queue, &msgnum);
498 // Run through the queue sending out messages.
499 void smtp_do_queue(void) {
500 static int doing_smtpclient = 0;
501 static long last_queue_msg_processed = 0;
504 // This is a concurrency check to make sure only one smtpclient run is done at a time.
505 begin_critical_section(S_SMTPQUEUE);
506 if (doing_smtpclient) {
507 end_critical_section(S_SMTPQUEUE);
510 doing_smtpclient = 1;
511 end_critical_section(S_SMTPQUEUE);
513 syslog(LOG_DEBUG, "smtpclient: start queue run - last_queue_msg_processed=%ld", last_queue_msg_processed);
515 if (CtdlGetRoom(&CC->room, SMTP_SPOOLOUT_ROOM) != 0) {
516 syslog(LOG_WARNING, "smtpclient: cannot find room <%s>", SMTP_SPOOLOUT_ROOM);
517 doing_smtpclient = 0;
521 // This array will hold the list of queue instruction messages
522 Array *smtp_queue = array_new(sizeof(long));
523 if (smtp_queue == NULL) {
524 syslog(LOG_WARNING, "smtpclient: cannot allocate queue array");
525 doing_smtpclient = 0;
529 // Put the queue in memory so we can close the db cursor
530 // Searching for messages with a top level Content-type of SPOOLIME will give us only queue instruction messages.
531 CtdlForEachMessage(MSGS_ALL, 0L, NULL, SPOOLMIME, NULL, smtp_add_msg, (void *)smtp_queue);
533 // We are ready to run through the queue now.
534 for (i = 0; i < array_len(smtp_queue); ++i) {
536 memcpy(&m, array_get_element_at(smtp_queue, i), sizeof(long));
537 smtp_process_one_msg(m);
538 last_queue_msg_processed = m;
541 array_free(smtp_queue);
542 doing_smtpclient = 0;
543 syslog(LOG_DEBUG, "smtpclient: end queue run - last_queue_msg_processed=%ld", last_queue_msg_processed);
547 // Initialization function, called from modules_init.c
548 char *ctdl_module_init_smtpclient(void) {
550 CtdlRegisterMessageHook(smtp_aftersave, EVT_AFTERSAVE);
551 CtdlRegisterSessionHook(smtp_do_queue, EVT_TIMER, PRIO_AGGR + 51);
552 smtp_init_spoolout();
555 // return our module id for the log