1 /* $Cambridge: exim/src/src/smtp_out.c,v 1.1 2004/10/07 10:39:01 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2004 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* A number of functions for driving outgoing SMTP calls. */
17 /*************************************************
18 * Find an outgoing interface *
19 *************************************************/
21 /* This function is called from the smtp transport and also from the callout
22 code in verify.c. Its job is to expand a string to get a list of interfaces,
23 and choose a suitable one (IPv4 or IPv6) for the outgoing address.
26 istring string interface setting, may be NULL, meaning "any", in
27 which case the function does nothing
28 host_af AF_INET or AF_INET6 for the outgoing IP address
29 addr the mail address being handled (for setting errors)
30 changed if not NULL, set TRUE if expansion actually changed istring
31 interface point this to the interface
32 msg to add to any error message
34 Returns: TRUE on success, FALSE on failure, with error message
35 set in addr and transport_return set to PANIC
39 smtp_get_interface(uschar *istring, int host_af, address_item *addr,
40 BOOL *changed, uschar **interface, uschar *msg)
46 if (istring == NULL) return TRUE;
48 expint = expand_string(istring);
51 if (expand_string_forcedfail) return TRUE;
52 addr->transport_return = PANIC;
53 addr->message = string_sprintf("failed to expand \"interface\" "
54 "option for %s: %s", msg, expand_string_message);
58 if (changed != NULL) *changed = expint != istring;
60 while (isspace(*expint)) expint++;
61 if (*expint == 0) return TRUE;
63 while ((iface = string_nextinlist(&expint, &sep, big_buffer,
64 big_buffer_size)) != NULL)
66 if (string_is_ip_address(iface, NULL) == 0)
68 addr->transport_return = PANIC;
69 addr->message = string_sprintf("\"%s\" is not a valid IP "
70 "address for the \"interface\" option for %s",
75 if (((Ustrchr(iface, ':') == NULL)? AF_INET:AF_INET6) == host_af)
79 if (iface != NULL) *interface = string_copy(iface);
85 /*************************************************
86 * Find an outgoing port *
87 *************************************************/
89 /* This function is called from the smtp transport and also from the callout
90 code in verify.c. Its job is to find a port number. Note that getservbyname()
91 produces the number in network byte order.
94 rstring raw (unexpanded) string representation of the port
95 addr the mail address being handled (for setting errors)
96 port stick the port in here
97 msg for adding to error message
99 Returns: TRUE on success, FALSE on failure, with error message set
100 in addr, and transport_return set to PANIC
104 smtp_get_port(uschar *rstring, address_item *addr, int *port, uschar *msg)
106 uschar *pstring = expand_string(rstring);
110 addr->transport_return = PANIC;
111 addr->message = string_sprintf("failed to expand \"%s\" (\"port\" option) "
112 "for %s: %s", rstring, msg, expand_string_message);
116 if (isdigit(*pstring))
119 *port = Ustrtol(pstring, &end, 0);
120 if (end != pstring + Ustrlen(pstring))
122 addr->transport_return = PANIC;
123 addr->message = string_sprintf("invalid port number for %s: %s", msg,
131 struct servent *smtp_service = getservbyname(CS pstring, "tcp");
132 if (smtp_service == NULL)
134 addr->transport_return = PANIC;
135 addr->message = string_sprintf("TCP port \"%s\" is not defined for %s",
139 *port = ntohs(smtp_service->s_port);
148 /*************************************************
149 * Connect to remote host *
150 *************************************************/
152 /* Create a socket, and connect it to a remote host. IPv6 addresses are
153 detected by checking for a colon in the address. AF_INET6 is defined even on
154 non-IPv6 systems, to enable the code to be less messy. However, on such systems
155 host->address will always be an IPv4 address.
157 The port field in the host item is used if it is set (usually router from SRV
158 records). In other cases, the default passed as an argument is used.
161 host host item containing name and address (and sometimes port)
162 host_af AF_INET or AF_INET6
163 port default, remote port to connect to, in host byte order for those
164 hosts whose port setting is PORT_NONE
165 interface outgoing interface address or NULL
166 timeout timeout value or 0
167 keepalive TRUE to use keepalive
169 Returns: connected socket number, or -1 with errno set
173 smtp_connect(host_item *host, int host_af, int port, uschar *interface,
174 int timeout, BOOL keepalive)
180 if (host->port != PORT_NONE)
182 HDEBUG(D_transport|D_acl|D_v)
183 debug_printf("Transport port=%d replaced by host-specific port=%d\n", port,
188 HDEBUG(D_transport|D_acl|D_v)
190 if (interface == NULL)
191 debug_printf("Connecting to %s [%s]:%d ... ",host->name,host->address,port);
193 debug_printf("Connecting to %s [%s]:%d from %s ... ", host->name,
194 host->address, port, interface);
197 /* Create the socket */
199 if ((sock = ip_socket(SOCK_STREAM, host_af)) < 0) return -1;
201 /* Set TCP_NODELAY; Exim does its own buffering. */
203 setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (uschar *)(&on), sizeof(on));
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. */
208 if (interface != NULL && ip_bind(sock, host_af, interface, 0) < 0)
211 HDEBUG(D_transport|D_acl|D_v)
212 debug_printf("unable to bind outgoing SMTP call to %s: %s", interface,
216 /* Connect to the remote host, and add keepalive to the socket before returning
219 else if (ip_connect(sock, host_af, host->address, port, timeout) < 0)
222 /* Either bind() or connect() failed */
226 HDEBUG(D_transport|D_acl|D_v) debug_printf("failed\n");
232 /* Both bind() and connect() succeeded */
236 HDEBUG(D_transport|D_acl|D_v) debug_printf("connected\n");
237 if (keepalive) ip_keepalive(sock, host->address, TRUE);
243 /*************************************************
244 * Flush outgoing command buffer *
245 *************************************************/
247 /* This function is called only from smtp_write_command() below. It flushes
248 the buffer of outgoing commands. There is more than one in the buffer only when
252 outblock the SMTP output block
254 Returns: TRUE if OK, FALSE on error, with errno set
258 flush_buffer(smtp_outblock *outblock)
263 if (tls_active == outblock->sock)
264 rc = tls_write(outblock->buffer, outblock->ptr - outblock->buffer);
268 rc = send(outblock->sock, outblock->buffer, outblock->ptr - outblock->buffer, 0);
271 HDEBUG(D_transport|D_acl) debug_printf("send failed: %s\n", strerror(errno));
275 outblock->ptr = outblock->buffer;
276 outblock->cmd_count = 0;
282 /*************************************************
283 * Write SMTP command *
284 *************************************************/
286 /* The formatted command is left in big_buffer so that it can be reflected in
290 outblock contains buffer for pipelining, and socket
291 noflush if TRUE, save the command in the output buffer, for pipelining
292 format a format, starting with one of
293 of HELO, MAIL FROM, RCPT TO, DATA, ".", or QUIT.
294 ... data for the format
296 Returns: 0 if command added to pipelining buffer, with nothing transmitted
297 +n if n commands transmitted (may still have buffered the new one)
298 -1 on error, with errno set
302 smtp_write_command(smtp_outblock *outblock, BOOL noflush, char *format, ...)
308 va_start(ap, format);
309 if (!string_vformat(big_buffer, big_buffer_size, CS format, ap))
310 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
313 count = Ustrlen(big_buffer);
315 if (count > outblock->buffersize - (outblock->ptr - outblock->buffer))
317 rc = outblock->cmd_count; /* flush resets */
318 if (!flush_buffer(outblock)) return -1;
321 Ustrncpy(CS outblock->ptr, big_buffer, count);
322 outblock->ptr += count;
323 outblock->cmd_count++;
325 big_buffer[count] = 0; /* remove \r\n for error message */
327 /* We want to hide the actual data sent in AUTH transactions from reflections
328 and logs. While authenticating, a flag is set in the outblock to enable this.
329 The AUTH command itself gets any data flattened. Other lines are flattened
332 if (outblock->authenticating)
334 uschar *p = big_buffer;
335 if (Ustrncmp(big_buffer, "AUTH ", 5) == 0)
338 while (isspace(*p)) p++;
339 while (!isspace(*p)) p++;
340 while (isspace(*p)) p++;
342 while (*p != 0) *p++ = '*';
345 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> %s\n", big_buffer);
349 rc += outblock->cmd_count; /* flush resets */
350 if (!flush_buffer(outblock)) return -1;
358 /*************************************************
359 * Read one line of SMTP response *
360 *************************************************/
362 /* This function reads one line of SMTP response from the server host. This may
363 not be a complete response - it could be just part of a multiline response. We
364 have to use a buffer for incoming packets, because when pipelining or using
365 LMTP, there may well be more than one response in a single packet. This
366 function is called only from the one that follows.
369 inblock the SMTP input block (contains holding buffer, socket, etc.)
370 buffer where to put the line
371 size space available for the line
372 timeout the timeout to use when reading a packet
374 Returns: length of a line that has been put in the buffer
375 -1 otherwise, with errno set
379 read_response_line(smtp_inblock *inblock, uschar *buffer, int size, int timeout)
382 uschar *ptr = inblock->ptr;
383 uschar *ptrend = inblock->ptrend;
384 int sock = inblock->sock;
386 /* Loop for reading multiple packets or reading another packet after emptying
387 a previously-read one. */
393 /* If there is data in the input buffer left over from last time, copy
394 characters from it until the end of a line, at which point we can return,
395 having removed any whitespace (which will include CR) at the end of the line.
396 The rules for SMTP say that lines end in CRLF, but there are have been cases
397 of hosts using just LF, and other MTAs are reported to handle this, so we
398 just look for LF. If we run out of characters before the end of a line,
399 carry on to read the next incoming packet. */
406 while (p > buffer && isspace(p[-1])) p--;
414 *p = 0; /* Leave malformed line for error message */
415 errno = ERRNO_SMTPFORMAT;
420 /* Need to read a new input packet. */
422 rc = ip_recv(sock, inblock->buffer, inblock->buffersize, timeout);
425 /* Another block of data has been successfully read. Set up the pointers
426 and let the loop continue. */
428 ptrend = inblock->ptrend = inblock->buffer + rc;
429 ptr = inblock->buffer;
430 DEBUG(D_transport|D_acl) debug_printf("read response data: size=%d\n", rc);
433 /* Get here if there has been some kind of recv() error; errno is set, but we
434 ensure that the result buffer is empty before returning. */
444 /*************************************************
445 * Read SMTP response *
446 *************************************************/
448 /* This function reads an SMTP response with a timeout, and returns the
449 response in the given buffer, as a string. A multiline response will contain
450 newline characters between the lines. The function also analyzes the first
451 digit of the reply code and returns FALSE if it is not acceptable. FALSE is
452 also returned after a reading error. In this case buffer[0] will be zero, and
453 the error code will be in errno.
456 inblock the SMTP input block (contains holding buffer, socket, etc.)
457 buffer where to put the response
458 size the size of the buffer
459 okdigit the expected first digit of the response
460 timeout the timeout to use
462 Returns: TRUE if a valid, non-error response was received; else FALSE
466 smtp_read_response(smtp_inblock *inblock, uschar *buffer, int size, int okdigit,
469 uschar *ptr = buffer;
472 errno = 0; /* Ensure errno starts out zero */
474 /* This is a loop to read and concatentate the lines that make up a multi-line
479 if ((count = read_response_line(inblock, ptr, size, timeout)) < 0)
482 HDEBUG(D_transport|D_acl|D_v)
483 debug_printf(" %s %s\n", (ptr == buffer)? "SMTP<<" : " ", ptr);
485 /* Check the format of the response: it must start with three digits; if
486 these are followed by a space or end of line, the response is complete. If
487 they are followed by '-' this is a multi-line response and we must look for
488 another line until the final line is reached. The only use made of multi-line
489 responses is to pass them back as error messages. We therefore just
490 concatenate them all within the buffer, which should be large enough to
491 accept any reasonable number of lines. */
497 (ptr[3] != '-' && ptr[3] != ' ' && ptr[3] != 0))
499 errno = ERRNO_SMTPFORMAT; /* format error */
503 /* If the line we have just read is a terminal line, line, we are done.
504 Otherwise more data has to be read. */
506 if (ptr[3] != '-') break;
508 /* Move the reading pointer upwards in the buffer and insert \n between the
509 components of a multiline response. Space is left for this by read_response_
517 /* Return a value that depends on the SMTP return code. On some systems a
518 non-zero value of errno has been seen at this point, so ensure it is zero,
519 because the caller of this function looks at errno when FALSE is returned, to
520 distinguish between an unexpected return code and other errors such as
521 timeouts, lost connections, etc. */
524 return buffer[0] == okdigit;
527 /* End of smtp_out.c */