Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
0a49a7a4 | 5 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
8 | /* A number of functions for driving outgoing SMTP calls. */ | |
9 | ||
10 | ||
11 | #include "exim.h" | |
12 | ||
13 | ||
14 | ||
15 | /************************************************* | |
16 | * Find an outgoing interface * | |
17 | *************************************************/ | |
18 | ||
19 | /* This function is called from the smtp transport and also from the callout | |
20 | code in verify.c. Its job is to expand a string to get a list of interfaces, | |
21 | and choose a suitable one (IPv4 or IPv6) for the outgoing address. | |
22 | ||
23 | Arguments: | |
24 | istring string interface setting, may be NULL, meaning "any", in | |
25 | which case the function does nothing | |
26 | host_af AF_INET or AF_INET6 for the outgoing IP address | |
27 | addr the mail address being handled (for setting errors) | |
28 | changed if not NULL, set TRUE if expansion actually changed istring | |
29 | interface point this to the interface | |
30 | msg to add to any error message | |
31 | ||
32 | Returns: TRUE on success, FALSE on failure, with error message | |
33 | set in addr and transport_return set to PANIC | |
34 | */ | |
35 | ||
36 | BOOL | |
37 | smtp_get_interface(uschar *istring, int host_af, address_item *addr, | |
38 | BOOL *changed, uschar **interface, uschar *msg) | |
39 | { | |
40 | uschar *expint; | |
41 | uschar *iface; | |
42 | int sep = 0; | |
43 | ||
44 | if (istring == NULL) return TRUE; | |
45 | ||
46 | expint = expand_string(istring); | |
47 | if (expint == NULL) | |
48 | { | |
49 | if (expand_string_forcedfail) return TRUE; | |
50 | addr->transport_return = PANIC; | |
51 | addr->message = string_sprintf("failed to expand \"interface\" " | |
52 | "option for %s: %s", msg, expand_string_message); | |
53 | return FALSE; | |
54 | } | |
55 | ||
56 | if (changed != NULL) *changed = expint != istring; | |
57 | ||
58 | while (isspace(*expint)) expint++; | |
59 | if (*expint == 0) return TRUE; | |
60 | ||
61 | while ((iface = string_nextinlist(&expint, &sep, big_buffer, | |
62 | big_buffer_size)) != NULL) | |
63 | { | |
64 | if (string_is_ip_address(iface, NULL) == 0) | |
65 | { | |
66 | addr->transport_return = PANIC; | |
67 | addr->message = string_sprintf("\"%s\" is not a valid IP " | |
68 | "address for the \"interface\" option for %s", | |
69 | iface, msg); | |
70 | return FALSE; | |
71 | } | |
72 | ||
73 | if (((Ustrchr(iface, ':') == NULL)? AF_INET:AF_INET6) == host_af) | |
74 | break; | |
75 | } | |
76 | ||
77 | if (iface != NULL) *interface = string_copy(iface); | |
78 | return TRUE; | |
79 | } | |
80 | ||
81 | ||
82 | ||
83 | /************************************************* | |
84 | * Find an outgoing port * | |
85 | *************************************************/ | |
86 | ||
87 | /* This function is called from the smtp transport and also from the callout | |
88 | code in verify.c. Its job is to find a port number. Note that getservbyname() | |
89 | produces the number in network byte order. | |
90 | ||
91 | Arguments: | |
92 | rstring raw (unexpanded) string representation of the port | |
93 | addr the mail address being handled (for setting errors) | |
94 | port stick the port in here | |
95 | msg for adding to error message | |
96 | ||
97 | Returns: TRUE on success, FALSE on failure, with error message set | |
98 | in addr, and transport_return set to PANIC | |
99 | */ | |
100 | ||
101 | BOOL | |
102 | smtp_get_port(uschar *rstring, address_item *addr, int *port, uschar *msg) | |
103 | { | |
104 | uschar *pstring = expand_string(rstring); | |
105 | ||
106 | if (pstring == NULL) | |
107 | { | |
108 | addr->transport_return = PANIC; | |
109 | addr->message = string_sprintf("failed to expand \"%s\" (\"port\" option) " | |
110 | "for %s: %s", rstring, msg, expand_string_message); | |
111 | return FALSE; | |
112 | } | |
113 | ||
114 | if (isdigit(*pstring)) | |
115 | { | |
116 | uschar *end; | |
117 | *port = Ustrtol(pstring, &end, 0); | |
118 | if (end != pstring + Ustrlen(pstring)) | |
119 | { | |
120 | addr->transport_return = PANIC; | |
121 | addr->message = string_sprintf("invalid port number for %s: %s", msg, | |
122 | pstring); | |
123 | return FALSE; | |
124 | } | |
125 | } | |
126 | ||
127 | else | |
128 | { | |
129 | struct servent *smtp_service = getservbyname(CS pstring, "tcp"); | |
130 | if (smtp_service == NULL) | |
131 | { | |
132 | addr->transport_return = PANIC; | |
133 | addr->message = string_sprintf("TCP port \"%s\" is not defined for %s", | |
134 | pstring, msg); | |
135 | return FALSE; | |
136 | } | |
137 | *port = ntohs(smtp_service->s_port); | |
138 | } | |
139 | ||
140 | return TRUE; | |
141 | } | |
142 | ||
143 | ||
144 | ||
145 | ||
146 | /************************************************* | |
147 | * Connect to remote host * | |
148 | *************************************************/ | |
149 | ||
150 | /* Create a socket, and connect it to a remote host. IPv6 addresses are | |
151 | detected by checking for a colon in the address. AF_INET6 is defined even on | |
152 | non-IPv6 systems, to enable the code to be less messy. However, on such systems | |
153 | host->address will always be an IPv4 address. | |
154 | ||
155 | The port field in the host item is used if it is set (usually router from SRV | |
2d280592 PH |
156 | records or elsewhere). In other cases, the default passed as an argument is |
157 | used, and the host item is updated with its value. | |
059ec3d9 PH |
158 | |
159 | Arguments: | |
160 | host host item containing name and address (and sometimes port) | |
161 | host_af AF_INET or AF_INET6 | |
2d280592 | 162 | port default remote port to connect to, in host byte order, for those |
059ec3d9 PH |
163 | hosts whose port setting is PORT_NONE |
164 | interface outgoing interface address or NULL | |
165 | timeout timeout value or 0 | |
166 | keepalive TRUE to use keepalive | |
167 | ||
168 | Returns: connected socket number, or -1 with errno set | |
169 | */ | |
170 | ||
171 | int | |
172 | smtp_connect(host_item *host, int host_af, int port, uschar *interface, | |
173 | int timeout, BOOL keepalive) | |
174 | { | |
175 | int on = 1; | |
176 | int save_errno = 0; | |
177 | int sock; | |
178 | ||
179 | if (host->port != PORT_NONE) | |
180 | { | |
181 | HDEBUG(D_transport|D_acl|D_v) | |
182 | debug_printf("Transport port=%d replaced by host-specific port=%d\n", port, | |
183 | host->port); | |
184 | port = host->port; | |
185 | } | |
2d280592 | 186 | else host->port = port; /* Set the port actually used */ |
059ec3d9 PH |
187 | |
188 | HDEBUG(D_transport|D_acl|D_v) | |
189 | { | |
190 | if (interface == NULL) | |
191 | debug_printf("Connecting to %s [%s]:%d ... ",host->name,host->address,port); | |
192 | else | |
193 | debug_printf("Connecting to %s [%s]:%d from %s ... ", host->name, | |
194 | host->address, port, interface); | |
195 | } | |
196 | ||
197 | /* Create the socket */ | |
198 | ||
199 | if ((sock = ip_socket(SOCK_STREAM, host_af)) < 0) return -1; | |
200 | ||
201 | /* Set TCP_NODELAY; Exim does its own buffering. */ | |
202 | ||
203 | setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (uschar *)(&on), sizeof(on)); | |
204 | ||
205 | /* Bind to a specific interface if requested. Caller must ensure the interface | |
206 | is the same type (IPv4 or IPv6) as the outgoing address. */ | |
207 | ||
208 | if (interface != NULL && ip_bind(sock, host_af, interface, 0) < 0) | |
209 | { | |
210 | save_errno = errno; | |
211 | HDEBUG(D_transport|D_acl|D_v) | |
212 | debug_printf("unable to bind outgoing SMTP call to %s: %s", interface, | |
213 | strerror(errno)); | |
214 | } | |
215 | ||
216 | /* Connect to the remote host, and add keepalive to the socket before returning | |
217 | it, if requested. */ | |
218 | ||
219 | else if (ip_connect(sock, host_af, host->address, port, timeout) < 0) | |
220 | save_errno = errno; | |
221 | ||
222 | /* Either bind() or connect() failed */ | |
223 | ||
224 | if (save_errno != 0) | |
225 | { | |
8e669ac1 | 226 | HDEBUG(D_transport|D_acl|D_v) |
4deaf07d PH |
227 | { |
228 | debug_printf("failed: %s", CUstrerror(save_errno)); | |
8e669ac1 | 229 | if (save_errno == ETIMEDOUT) |
4deaf07d | 230 | debug_printf(" (timeout=%s)", readconf_printtime(timeout)); |
8e669ac1 PH |
231 | debug_printf("\n"); |
232 | } | |
f1e894f3 | 233 | (void)close(sock); |
059ec3d9 PH |
234 | errno = save_errno; |
235 | return -1; | |
236 | } | |
237 | ||
238 | /* Both bind() and connect() succeeded */ | |
239 | ||
240 | else | |
241 | { | |
41c7c167 PH |
242 | union sockaddr_46 interface_sock; |
243 | EXIM_SOCKLEN_T size = sizeof(interface_sock); | |
059ec3d9 | 244 | HDEBUG(D_transport|D_acl|D_v) debug_printf("connected\n"); |
41c7c167 PH |
245 | if (getsockname(sock, (struct sockaddr *)(&interface_sock), &size) == 0) |
246 | sending_ip_address = host_ntoa(-1, &interface_sock, NULL, &sending_port); | |
247 | else | |
248 | { | |
249 | log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC), | |
250 | "getsockname() failed: %s", strerror(errno)); | |
251 | close(sock); | |
252 | return -1; | |
253 | } | |
059ec3d9 PH |
254 | if (keepalive) ip_keepalive(sock, host->address, TRUE); |
255 | return sock; | |
256 | } | |
257 | } | |
258 | ||
259 | ||
260 | /************************************************* | |
261 | * Flush outgoing command buffer * | |
262 | *************************************************/ | |
263 | ||
264 | /* This function is called only from smtp_write_command() below. It flushes | |
265 | the buffer of outgoing commands. There is more than one in the buffer only when | |
266 | pipelining. | |
267 | ||
268 | Argument: | |
269 | outblock the SMTP output block | |
270 | ||
271 | Returns: TRUE if OK, FALSE on error, with errno set | |
272 | */ | |
273 | ||
274 | static BOOL | |
275 | flush_buffer(smtp_outblock *outblock) | |
276 | { | |
277 | int rc; | |
278 | ||
279 | #ifdef SUPPORT_TLS | |
280 | if (tls_active == outblock->sock) | |
281 | rc = tls_write(outblock->buffer, outblock->ptr - outblock->buffer); | |
282 | else | |
283 | #endif | |
284 | ||
285 | rc = send(outblock->sock, outblock->buffer, outblock->ptr - outblock->buffer, 0); | |
286 | if (rc <= 0) | |
287 | { | |
288 | HDEBUG(D_transport|D_acl) debug_printf("send failed: %s\n", strerror(errno)); | |
289 | return FALSE; | |
290 | } | |
291 | ||
292 | outblock->ptr = outblock->buffer; | |
293 | outblock->cmd_count = 0; | |
294 | return TRUE; | |
295 | } | |
296 | ||
297 | ||
298 | ||
299 | /************************************************* | |
300 | * Write SMTP command * | |
301 | *************************************************/ | |
302 | ||
303 | /* The formatted command is left in big_buffer so that it can be reflected in | |
304 | any error message. | |
305 | ||
306 | Arguments: | |
307 | outblock contains buffer for pipelining, and socket | |
308 | noflush if TRUE, save the command in the output buffer, for pipelining | |
309 | format a format, starting with one of | |
310 | of HELO, MAIL FROM, RCPT TO, DATA, ".", or QUIT. | |
311 | ... data for the format | |
312 | ||
313 | Returns: 0 if command added to pipelining buffer, with nothing transmitted | |
314 | +n if n commands transmitted (may still have buffered the new one) | |
315 | -1 on error, with errno set | |
316 | */ | |
317 | ||
318 | int | |
1ba28e2b | 319 | smtp_write_command(smtp_outblock *outblock, BOOL noflush, const char *format, ...) |
059ec3d9 PH |
320 | { |
321 | int count; | |
322 | int rc = 0; | |
323 | va_list ap; | |
324 | ||
325 | va_start(ap, format); | |
326 | if (!string_vformat(big_buffer, big_buffer_size, CS format, ap)) | |
327 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing " | |
328 | "SMTP"); | |
329 | va_end(ap); | |
330 | count = Ustrlen(big_buffer); | |
331 | ||
332 | if (count > outblock->buffersize - (outblock->ptr - outblock->buffer)) | |
333 | { | |
334 | rc = outblock->cmd_count; /* flush resets */ | |
335 | if (!flush_buffer(outblock)) return -1; | |
336 | } | |
337 | ||
338 | Ustrncpy(CS outblock->ptr, big_buffer, count); | |
339 | outblock->ptr += count; | |
340 | outblock->cmd_count++; | |
341 | count -= 2; | |
342 | big_buffer[count] = 0; /* remove \r\n for error message */ | |
343 | ||
344 | /* We want to hide the actual data sent in AUTH transactions from reflections | |
345 | and logs. While authenticating, a flag is set in the outblock to enable this. | |
346 | The AUTH command itself gets any data flattened. Other lines are flattened | |
347 | completely. */ | |
348 | ||
349 | if (outblock->authenticating) | |
350 | { | |
351 | uschar *p = big_buffer; | |
352 | if (Ustrncmp(big_buffer, "AUTH ", 5) == 0) | |
353 | { | |
354 | p += 5; | |
355 | while (isspace(*p)) p++; | |
356 | while (!isspace(*p)) p++; | |
357 | while (isspace(*p)) p++; | |
358 | } | |
359 | while (*p != 0) *p++ = '*'; | |
360 | } | |
361 | ||
362 | HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> %s\n", big_buffer); | |
363 | ||
364 | if (!noflush) | |
365 | { | |
366 | rc += outblock->cmd_count; /* flush resets */ | |
367 | if (!flush_buffer(outblock)) return -1; | |
368 | } | |
369 | ||
370 | return rc; | |
371 | } | |
372 | ||
373 | ||
374 | ||
375 | /************************************************* | |
376 | * Read one line of SMTP response * | |
377 | *************************************************/ | |
378 | ||
379 | /* This function reads one line of SMTP response from the server host. This may | |
380 | not be a complete response - it could be just part of a multiline response. We | |
381 | have to use a buffer for incoming packets, because when pipelining or using | |
382 | LMTP, there may well be more than one response in a single packet. This | |
383 | function is called only from the one that follows. | |
384 | ||
385 | Arguments: | |
386 | inblock the SMTP input block (contains holding buffer, socket, etc.) | |
387 | buffer where to put the line | |
388 | size space available for the line | |
389 | timeout the timeout to use when reading a packet | |
390 | ||
391 | Returns: length of a line that has been put in the buffer | |
392 | -1 otherwise, with errno set | |
393 | */ | |
394 | ||
395 | static int | |
396 | read_response_line(smtp_inblock *inblock, uschar *buffer, int size, int timeout) | |
397 | { | |
398 | uschar *p = buffer; | |
399 | uschar *ptr = inblock->ptr; | |
400 | uschar *ptrend = inblock->ptrend; | |
401 | int sock = inblock->sock; | |
402 | ||
403 | /* Loop for reading multiple packets or reading another packet after emptying | |
404 | a previously-read one. */ | |
405 | ||
406 | for (;;) | |
407 | { | |
408 | int rc; | |
409 | ||
410 | /* If there is data in the input buffer left over from last time, copy | |
411 | characters from it until the end of a line, at which point we can return, | |
412 | having removed any whitespace (which will include CR) at the end of the line. | |
413 | The rules for SMTP say that lines end in CRLF, but there are have been cases | |
414 | of hosts using just LF, and other MTAs are reported to handle this, so we | |
415 | just look for LF. If we run out of characters before the end of a line, | |
416 | carry on to read the next incoming packet. */ | |
417 | ||
418 | while (ptr < ptrend) | |
419 | { | |
420 | int c = *ptr++; | |
421 | if (c == '\n') | |
422 | { | |
423 | while (p > buffer && isspace(p[-1])) p--; | |
424 | *p = 0; | |
425 | inblock->ptr = ptr; | |
426 | return p - buffer; | |
427 | } | |
428 | *p++ = c; | |
429 | if (--size < 4) | |
430 | { | |
431 | *p = 0; /* Leave malformed line for error message */ | |
432 | errno = ERRNO_SMTPFORMAT; | |
433 | return -1; | |
434 | } | |
435 | } | |
436 | ||
437 | /* Need to read a new input packet. */ | |
438 | ||
439 | rc = ip_recv(sock, inblock->buffer, inblock->buffersize, timeout); | |
440 | if (rc <= 0) break; | |
441 | ||
442 | /* Another block of data has been successfully read. Set up the pointers | |
443 | and let the loop continue. */ | |
444 | ||
445 | ptrend = inblock->ptrend = inblock->buffer + rc; | |
446 | ptr = inblock->buffer; | |
447 | DEBUG(D_transport|D_acl) debug_printf("read response data: size=%d\n", rc); | |
448 | } | |
449 | ||
450 | /* Get here if there has been some kind of recv() error; errno is set, but we | |
451 | ensure that the result buffer is empty before returning. */ | |
452 | ||
453 | *buffer = 0; | |
454 | return -1; | |
455 | } | |
456 | ||
457 | ||
458 | ||
459 | ||
460 | ||
461 | /************************************************* | |
462 | * Read SMTP response * | |
463 | *************************************************/ | |
464 | ||
465 | /* This function reads an SMTP response with a timeout, and returns the | |
466 | response in the given buffer, as a string. A multiline response will contain | |
467 | newline characters between the lines. The function also analyzes the first | |
468 | digit of the reply code and returns FALSE if it is not acceptable. FALSE is | |
469 | also returned after a reading error. In this case buffer[0] will be zero, and | |
470 | the error code will be in errno. | |
471 | ||
472 | Arguments: | |
473 | inblock the SMTP input block (contains holding buffer, socket, etc.) | |
474 | buffer where to put the response | |
475 | size the size of the buffer | |
476 | okdigit the expected first digit of the response | |
477 | timeout the timeout to use | |
478 | ||
479 | Returns: TRUE if a valid, non-error response was received; else FALSE | |
480 | */ | |
481 | ||
482 | BOOL | |
483 | smtp_read_response(smtp_inblock *inblock, uschar *buffer, int size, int okdigit, | |
484 | int timeout) | |
485 | { | |
486 | uschar *ptr = buffer; | |
487 | int count; | |
488 | ||
489 | errno = 0; /* Ensure errno starts out zero */ | |
490 | ||
491 | /* This is a loop to read and concatentate the lines that make up a multi-line | |
492 | response. */ | |
493 | ||
494 | for (;;) | |
495 | { | |
496 | if ((count = read_response_line(inblock, ptr, size, timeout)) < 0) | |
497 | return FALSE; | |
498 | ||
499 | HDEBUG(D_transport|D_acl|D_v) | |
500 | debug_printf(" %s %s\n", (ptr == buffer)? "SMTP<<" : " ", ptr); | |
501 | ||
502 | /* Check the format of the response: it must start with three digits; if | |
503 | these are followed by a space or end of line, the response is complete. If | |
504 | they are followed by '-' this is a multi-line response and we must look for | |
505 | another line until the final line is reached. The only use made of multi-line | |
506 | responses is to pass them back as error messages. We therefore just | |
507 | concatenate them all within the buffer, which should be large enough to | |
508 | accept any reasonable number of lines. */ | |
509 | ||
510 | if (count < 3 || | |
511 | !isdigit(ptr[0]) || | |
512 | !isdigit(ptr[1]) || | |
513 | !isdigit(ptr[2]) || | |
514 | (ptr[3] != '-' && ptr[3] != ' ' && ptr[3] != 0)) | |
515 | { | |
516 | errno = ERRNO_SMTPFORMAT; /* format error */ | |
517 | return FALSE; | |
518 | } | |
519 | ||
520 | /* If the line we have just read is a terminal line, line, we are done. | |
521 | Otherwise more data has to be read. */ | |
522 | ||
523 | if (ptr[3] != '-') break; | |
524 | ||
525 | /* Move the reading pointer upwards in the buffer and insert \n between the | |
526 | components of a multiline response. Space is left for this by read_response_ | |
527 | line(). */ | |
528 | ||
529 | ptr += count; | |
530 | *ptr++ = '\n'; | |
531 | size -= count + 1; | |
532 | } | |
533 | ||
534 | /* Return a value that depends on the SMTP return code. On some systems a | |
535 | non-zero value of errno has been seen at this point, so ensure it is zero, | |
536 | because the caller of this function looks at errno when FALSE is returned, to | |
537 | distinguish between an unexpected return code and other errors such as | |
538 | timeouts, lost connections, etc. */ | |
539 | ||
540 | errno = 0; | |
541 | return buffer[0] == okdigit; | |
542 | } | |
543 | ||
544 | /* End of smtp_out.c */ |