1 /* $Cambridge: exim/src/src/smtp_out.c,v 1.10 2009/11/16 19:50:37 nm4 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2009 */
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 or elsewhere). In other cases, the default passed as an argument is
159 used, and the host item is updated with its value.
162 host host item containing name and address (and sometimes port)
163 host_af AF_INET or AF_INET6
164 port default remote port to connect to, in host byte order, for those
165 hosts whose port setting is PORT_NONE
166 interface outgoing interface address or NULL
167 timeout timeout value or 0
168 keepalive TRUE to use keepalive
170 Returns: connected socket number, or -1 with errno set
174 smtp_connect(host_item
*host
, int host_af
, int port
, uschar
*interface
,
175 int timeout
, BOOL keepalive
)
181 if (host
->port
!= PORT_NONE
)
183 HDEBUG(D_transport
|D_acl
|D_v
)
184 debug_printf("Transport port=%d replaced by host-specific port=%d\n", port
,
188 else host
->port
= port
; /* Set the port actually used */
190 HDEBUG(D_transport
|D_acl
|D_v
)
192 if (interface
== NULL
)
193 debug_printf("Connecting to %s [%s]:%d ... ",host
->name
,host
->address
,port
);
195 debug_printf("Connecting to %s [%s]:%d from %s ... ", host
->name
,
196 host
->address
, port
, interface
);
199 /* Create the socket */
201 if ((sock
= ip_socket(SOCK_STREAM
, host_af
)) < 0) return -1;
203 /* Set TCP_NODELAY; Exim does its own buffering. */
205 setsockopt(sock
, IPPROTO_TCP
, TCP_NODELAY
, (uschar
*)(&on
), sizeof(on
));
207 /* Bind to a specific interface if requested. Caller must ensure the interface
208 is the same type (IPv4 or IPv6) as the outgoing address. */
210 if (interface
!= NULL
&& ip_bind(sock
, host_af
, interface
, 0) < 0)
213 HDEBUG(D_transport
|D_acl
|D_v
)
214 debug_printf("unable to bind outgoing SMTP call to %s: %s", interface
,
218 /* Connect to the remote host, and add keepalive to the socket before returning
221 else if (ip_connect(sock
, host_af
, host
->address
, port
, timeout
) < 0)
224 /* Either bind() or connect() failed */
228 HDEBUG(D_transport
|D_acl
|D_v
)
230 debug_printf("failed: %s", CUstrerror(save_errno
));
231 if (save_errno
== ETIMEDOUT
)
232 debug_printf(" (timeout=%s)", readconf_printtime(timeout
));
240 /* Both bind() and connect() succeeded */
244 union sockaddr_46 interface_sock
;
245 EXIM_SOCKLEN_T size
= sizeof(interface_sock
);
246 HDEBUG(D_transport
|D_acl
|D_v
) debug_printf("connected\n");
247 if (getsockname(sock
, (struct sockaddr
*)(&interface_sock
), &size
) == 0)
248 sending_ip_address
= host_ntoa(-1, &interface_sock
, NULL
, &sending_port
);
251 log_write(0, LOG_MAIN
| ((errno
== ECONNRESET
)? 0 : LOG_PANIC
),
252 "getsockname() failed: %s", strerror(errno
));
256 if (keepalive
) ip_keepalive(sock
, host
->address
, TRUE
);
262 /*************************************************
263 * Flush outgoing command buffer *
264 *************************************************/
266 /* This function is called only from smtp_write_command() below. It flushes
267 the buffer of outgoing commands. There is more than one in the buffer only when
271 outblock the SMTP output block
273 Returns: TRUE if OK, FALSE on error, with errno set
277 flush_buffer(smtp_outblock
*outblock
)
282 if (tls_active
== outblock
->sock
)
283 rc
= tls_write(outblock
->buffer
, outblock
->ptr
- outblock
->buffer
);
287 rc
= send(outblock
->sock
, outblock
->buffer
, outblock
->ptr
- outblock
->buffer
, 0);
290 HDEBUG(D_transport
|D_acl
) debug_printf("send failed: %s\n", strerror(errno
));
294 outblock
->ptr
= outblock
->buffer
;
295 outblock
->cmd_count
= 0;
301 /*************************************************
302 * Write SMTP command *
303 *************************************************/
305 /* The formatted command is left in big_buffer so that it can be reflected in
309 outblock contains buffer for pipelining, and socket
310 noflush if TRUE, save the command in the output buffer, for pipelining
311 format a format, starting with one of
312 of HELO, MAIL FROM, RCPT TO, DATA, ".", or QUIT.
313 ... data for the format
315 Returns: 0 if command added to pipelining buffer, with nothing transmitted
316 +n if n commands transmitted (may still have buffered the new one)
317 -1 on error, with errno set
321 smtp_write_command(smtp_outblock
*outblock
, BOOL noflush
, char *format
, ...)
327 va_start(ap
, format
);
328 if (!string_vformat(big_buffer
, big_buffer_size
, CS format
, ap
))
329 log_write(0, LOG_MAIN
|LOG_PANIC_DIE
, "overlong write_command in outgoing "
332 count
= Ustrlen(big_buffer
);
334 if (count
> outblock
->buffersize
- (outblock
->ptr
- outblock
->buffer
))
336 rc
= outblock
->cmd_count
; /* flush resets */
337 if (!flush_buffer(outblock
)) return -1;
340 Ustrncpy(CS outblock
->ptr
, big_buffer
, count
);
341 outblock
->ptr
+= count
;
342 outblock
->cmd_count
++;
344 big_buffer
[count
] = 0; /* remove \r\n for error message */
346 /* We want to hide the actual data sent in AUTH transactions from reflections
347 and logs. While authenticating, a flag is set in the outblock to enable this.
348 The AUTH command itself gets any data flattened. Other lines are flattened
351 if (outblock
->authenticating
)
353 uschar
*p
= big_buffer
;
354 if (Ustrncmp(big_buffer
, "AUTH ", 5) == 0)
357 while (isspace(*p
)) p
++;
358 while (!isspace(*p
)) p
++;
359 while (isspace(*p
)) p
++;
361 while (*p
!= 0) *p
++ = '*';
364 HDEBUG(D_transport
|D_acl
|D_v
) debug_printf(" SMTP>> %s\n", big_buffer
);
368 rc
+= outblock
->cmd_count
; /* flush resets */
369 if (!flush_buffer(outblock
)) return -1;
377 /*************************************************
378 * Read one line of SMTP response *
379 *************************************************/
381 /* This function reads one line of SMTP response from the server host. This may
382 not be a complete response - it could be just part of a multiline response. We
383 have to use a buffer for incoming packets, because when pipelining or using
384 LMTP, there may well be more than one response in a single packet. This
385 function is called only from the one that follows.
388 inblock the SMTP input block (contains holding buffer, socket, etc.)
389 buffer where to put the line
390 size space available for the line
391 timeout the timeout to use when reading a packet
393 Returns: length of a line that has been put in the buffer
394 -1 otherwise, with errno set
398 read_response_line(smtp_inblock
*inblock
, uschar
*buffer
, int size
, int timeout
)
401 uschar
*ptr
= inblock
->ptr
;
402 uschar
*ptrend
= inblock
->ptrend
;
403 int sock
= inblock
->sock
;
405 /* Loop for reading multiple packets or reading another packet after emptying
406 a previously-read one. */
412 /* If there is data in the input buffer left over from last time, copy
413 characters from it until the end of a line, at which point we can return,
414 having removed any whitespace (which will include CR) at the end of the line.
415 The rules for SMTP say that lines end in CRLF, but there are have been cases
416 of hosts using just LF, and other MTAs are reported to handle this, so we
417 just look for LF. If we run out of characters before the end of a line,
418 carry on to read the next incoming packet. */
425 while (p
> buffer
&& isspace(p
[-1])) p
--;
433 *p
= 0; /* Leave malformed line for error message */
434 errno
= ERRNO_SMTPFORMAT
;
439 /* Need to read a new input packet. */
441 rc
= ip_recv(sock
, inblock
->buffer
, inblock
->buffersize
, timeout
);
444 /* Another block of data has been successfully read. Set up the pointers
445 and let the loop continue. */
447 ptrend
= inblock
->ptrend
= inblock
->buffer
+ rc
;
448 ptr
= inblock
->buffer
;
449 DEBUG(D_transport
|D_acl
) debug_printf("read response data: size=%d\n", rc
);
452 /* Get here if there has been some kind of recv() error; errno is set, but we
453 ensure that the result buffer is empty before returning. */
463 /*************************************************
464 * Read SMTP response *
465 *************************************************/
467 /* This function reads an SMTP response with a timeout, and returns the
468 response in the given buffer, as a string. A multiline response will contain
469 newline characters between the lines. The function also analyzes the first
470 digit of the reply code and returns FALSE if it is not acceptable. FALSE is
471 also returned after a reading error. In this case buffer[0] will be zero, and
472 the error code will be in errno.
475 inblock the SMTP input block (contains holding buffer, socket, etc.)
476 buffer where to put the response
477 size the size of the buffer
478 okdigit the expected first digit of the response
479 timeout the timeout to use
481 Returns: TRUE if a valid, non-error response was received; else FALSE
485 smtp_read_response(smtp_inblock
*inblock
, uschar
*buffer
, int size
, int okdigit
,
488 uschar
*ptr
= buffer
;
491 errno
= 0; /* Ensure errno starts out zero */
493 /* This is a loop to read and concatentate the lines that make up a multi-line
498 if ((count
= read_response_line(inblock
, ptr
, size
, timeout
)) < 0)
501 HDEBUG(D_transport
|D_acl
|D_v
)
502 debug_printf(" %s %s\n", (ptr
== buffer
)? "SMTP<<" : " ", ptr
);
504 /* Check the format of the response: it must start with three digits; if
505 these are followed by a space or end of line, the response is complete. If
506 they are followed by '-' this is a multi-line response and we must look for
507 another line until the final line is reached. The only use made of multi-line
508 responses is to pass them back as error messages. We therefore just
509 concatenate them all within the buffer, which should be large enough to
510 accept any reasonable number of lines. */
516 (ptr
[3] != '-' && ptr
[3] != ' ' && ptr
[3] != 0))
518 errno
= ERRNO_SMTPFORMAT
; /* format error */
522 /* If the line we have just read is a terminal line, line, we are done.
523 Otherwise more data has to be read. */
525 if (ptr
[3] != '-') break;
527 /* Move the reading pointer upwards in the buffer and insert \n between the
528 components of a multiline response. Space is left for this by read_response_
536 /* Return a value that depends on the SMTP return code. On some systems a
537 non-zero value of errno has been seen at this point, so ensure it is zero,
538 because the caller of this function looks at errno when FALSE is returned, to
539 distinguish between an unexpected return code and other errors such as
540 timeouts, lost connections, etc. */
543 return buffer
[0] == okdigit
;
546 /* End of smtp_out.c */