1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for doing things with sockets. With the advent of IPv6 this has
9 got messier, so that it's worth pulling out the code into separate functions
10 that other parts of Exim can call, expecially as there are now several
11 different places in the code where sockets are used. */
17 /*************************************************
19 *************************************************/
21 /* Socket creation happens in a number of places so it's packaged here for
25 type SOCK_DGRAM or SOCK_STREAM
26 af AF_INET or AF_INET6
28 Returns: socket number or -1 on failure
32 ip_socket(int type, int af)
34 int sock = socket(af, type, 0);
36 log_write(0, LOG_MAIN, "IPv%c socket creation failed: %s",
37 (af == AF_INET6)? '6':'4', strerror(errno));
45 /*************************************************
46 * Convert printing address to numeric *
47 *************************************************/
49 /* This function converts the textual form of an IP address into a numeric form
50 in an appropriate structure in an IPv6 environment. The getaddrinfo() function
51 can (apparently) handle more complicated addresses (e.g. those containing
52 scopes) than inet_pton() in some environments. We use hints to tell it that the
53 input must be a numeric address.
55 However, apparently some operating systems (or libraries) don't support
56 getaddrinfo(), so there is a build-time option to revert to inet_pton() (which
57 does not support scopes).
60 address textual form of the address
61 addr where to copy back the answer
63 Returns: nothing - failure provokes a panic-die
67 ip_addrinfo(const uschar *address, struct sockaddr_in6 *saddr)
69 #ifdef IPV6_USE_INET_PTON
71 if (inet_pton(AF_INET6, CCS address, &saddr->sin6_addr) != 1)
72 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
73 "IP address", address);
74 saddr->sin6_family = AF_INET6;
79 struct addrinfo hints, *res;
80 memset(&hints, 0, sizeof(hints));
81 hints.ai_family = AF_INET6;
82 hints.ai_socktype = SOCK_STREAM;
83 hints.ai_flags = AI_NUMERICHOST;
84 if ((rc = getaddrinfo(CCS address, NULL, &hints, &res)) != 0 || res == NULL)
85 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
86 "IP address: %s", address,
87 (rc == 0)? "NULL result returned" : gai_strerror(rc));
88 memcpy(saddr, res->ai_addr, res->ai_addrlen);
93 #endif /* HAVE_IPV6 */
96 /*************************************************
97 * Bind socket to interface and port *
98 *************************************************/
100 /* This function binds a socket to a local interface address and port. For a
101 wildcard IPv6 bind, the address is ":".
105 af AF_INET or AF_INET6 - the socket type
106 address the IP address, in text form
107 port the IP port (host order)
109 Returns: the result of bind()
113 ip_bind(int sock, int af, uschar *address, int port)
116 union sockaddr_46 sin;
117 memset(&sin, 0, sizeof(sin));
119 /* Setup code when using an IPv6 socket. The wildcard address is ":", to
120 ensure an IPv6 socket is used. */
125 if (address[0] == ':' && address[1] == 0)
127 sin.v6.sin6_family = AF_INET6;
128 sin.v6.sin6_addr = in6addr_any;
132 ip_addrinfo(address, &sin.v6); /* Panic-dies on error */
134 sin.v6.sin6_port = htons(port);
135 s_len = sizeof(sin.v6);
138 #else /* HAVE_IPv6 */
139 af = af; /* Avoid compiler warning */
140 #endif /* HAVE_IPV6 */
142 /* Setup code when using IPv4 socket. The wildcard address is "". */
145 sin.v4.sin_family = AF_INET;
146 sin.v4.sin_port = htons(port);
147 s_len = sizeof(sin.v4);
149 sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)INADDR_ANY;
151 sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(CS address);
154 /* Now we can call the bind() function */
156 return bind(sock, (struct sockaddr *)&sin, s_len);
161 /*************************************************
162 * Connect socket to remote host *
163 *************************************************/
165 /* This function connects a socket to a remote address and port. The socket may
166 or may not have previously been bound to a local interface. The socket is not
167 closed, even in cases of error. It is expected that the calling function, which
168 created the socket, will be the one that closes it.
172 af AF_INET6 or AF_INET for the socket type
173 address the remote address, in text form
175 timeout a timeout (zero for indefinite timeout)
177 Returns: 0 on success; -1 on failure, with errno set
181 ip_connect(int sock, int af, const uschar *address, int port, int timeout)
183 struct sockaddr_in s_in4;
184 struct sockaddr *s_ptr;
185 int s_len, rc, save_errno;
187 /* For an IPv6 address, use an IPv6 sockaddr structure. */
190 struct sockaddr_in6 s_in6;
193 memset(&s_in6, 0, sizeof(s_in6));
194 ip_addrinfo(address, &s_in6); /* Panic-dies on error */
195 s_in6.sin6_port = htons(port);
196 s_ptr = (struct sockaddr *)&s_in6;
197 s_len = sizeof(s_in6);
200 #else /* HAVE_IPV6 */
201 af = af; /* Avoid compiler warning */
202 #endif /* HAVE_IPV6 */
204 /* For an IPv4 address, use an IPv4 sockaddr structure, even on a system with
208 memset(&s_in4, 0, sizeof(s_in4));
209 s_in4.sin_family = AF_INET;
210 s_in4.sin_port = htons(port);
211 s_in4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(CCS address);
212 s_ptr = (struct sockaddr *)&s_in4;
213 s_len = sizeof(s_in4);
216 /* If no connection timeout is set, just call connect() without setting a
217 timer, thereby allowing the inbuilt OS timeout to operate. */
219 sigalrm_seen = FALSE;
220 if (timeout > 0) alarm(timeout);
221 rc = connect(sock, s_ptr, s_len);
225 /* There is a testing facility for simulating a connection timeout, as I
226 can't think of any other way of doing this. It converts a connection refused
227 into a timeout if the timeout is set to 999999. */
229 if (running_in_test_harness)
231 if (save_errno == ECONNREFUSED && timeout == 999999)
241 if (rc >= 0) return 0;
243 /* A failure whose error code is "Interrupted system call" is in fact
244 an externally applied timeout if the signal handler has been run. */
246 errno = (save_errno == EINTR && sigalrm_seen)? ETIMEDOUT : save_errno;
252 /*************************************************
253 * Create connected socket to remote host *
254 *************************************************/
256 /* Create a socket and connect to host (name or number, ipv6 ok)
257 at one of port-range.
260 type SOCK_DGRAM or SOCK_STREAM
261 af AF_INET6 or AF_INET for the socket type
262 address the remote address, in text form
263 portlo,porthi the remote port range
265 connhost if not NULL, host_item filled in with connection details
266 errstr pointer for allocated string on error
269 socket fd, or -1 on failure (having allocated an error string)
272 ip_connectedsocket(int type, const uschar * hostname, int portlo, int porthi,
273 int timeout, host_item * connhost, uschar ** errstr)
278 int af = 0, fd, fd4 = -1, fd6 = -1;
281 shost.address = NULL;
285 namelen = Ustrlen(hostname);
287 /* Anything enclosed in [] must be an IP address. */
289 if (hostname[0] == '[' &&
290 hostname[namelen - 1] == ']')
292 uschar * host = string_copy(hostname);
293 host[namelen - 1] = 0;
295 if (string_is_ip_address(host, NULL) == 0)
297 *errstr = string_sprintf("malformed IP address \"%s\"", hostname);
300 shost.name = shost.address = host;
303 /* Otherwise check for an unadorned IP address */
305 else if (string_is_ip_address(hostname, NULL) != 0)
306 shost.name = shost.address = string_copy(hostname);
308 /* Otherwise lookup IP address(es) from the name */
312 shost.name = string_copy(hostname);
313 if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE, NULL,
314 FALSE) != HOST_FOUND)
316 *errstr = string_sprintf("no IP address found for host %s", shost.name);
321 /* Try to connect to the server - test each IP till one works */
323 for (h = &shost; h != NULL; h = h->next)
325 fd = (Ustrchr(h->address, ':') != 0)
326 ? (fd6 < 0) ? (fd6 = ip_socket(type, af = AF_INET6)) : fd6
327 : (fd4 < 0) ? (fd4 = ip_socket(type, af = AF_INET )) : fd4;
331 *errstr = string_sprintf("failed to create socket: %s", strerror(errno));
335 for(port = portlo; port <= porthi; port++)
336 if (ip_connect(fd, af, h->address, port, timeout) == 0)
338 if (fd != fd6) close(fd6);
339 if (fd != fd4) close(fd4);
343 connhost->next = NULL;
349 *errstr = string_sprintf("failed to connect to any address for %s: %s",
350 hostname, strerror(errno));
353 close(fd4); close(fd6); return -1;
358 ip_tcpsocket(const uschar * hostport, uschar ** errstr, int tmo)
361 uschar hostname[256];
362 unsigned int portlow, porthigh;
364 /* extract host and port part */
365 scan = sscanf(CS hostport, "%255s %u-%u", hostname, &portlow, &porthigh);
368 *errstr = string_sprintf("invalid socket '%s'", hostport);
374 return ip_connectedsocket(SOCK_STREAM, hostname, portlow, porthigh,
379 ip_unixsocket(const uschar * path, uschar ** errstr)
382 struct sockaddr_un server;
384 if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
385 *errstr = US"can't open UNIX socket.";
389 server.sun_family = AF_UNIX;
390 Ustrncpy(server.sun_path, path, sizeof(server.sun_path)-1);
391 server.sun_path[sizeof(server.sun_path)-1] = '\0';
392 if (connect(sock, (struct sockaddr *) &server, sizeof(server)) < 0) {
395 *errstr = string_sprintf("unable to connect to UNIX socket (%s): %s",
396 path, strerror(err));
403 ip_streamsocket(const uschar * spec, uschar ** errstr, int tmo)
406 ? ip_unixsocket(spec, errstr) : ip_tcpsocket(spec, errstr, tmo);
409 /*************************************************
410 * Set keepalive on a socket *
411 *************************************************/
413 /* Can be called for both incoming and outgoing sockets.
417 address the remote host address, for failure logging
418 torf true for outgoing connection, false for incoming
424 ip_keepalive(int sock, uschar *address, BOOL torf)
427 if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
428 (uschar *)(&fodder), sizeof(fodder)) != 0)
429 log_write(0, LOG_MAIN, "setsockopt(SO_KEEPALIVE) on connection %s %s "
430 "failed: %s", torf? "to":"from", address, strerror(errno));
435 /*************************************************
436 * Receive from a socket with timeout *
437 *************************************************/
441 fd the file descriptor
442 timeout the timeout, seconds
443 Returns: TRUE => ready for i/o
444 FALSE => timed out, or other error
447 fd_ready(int fd, int timeout)
451 time_t start_recv = time(NULL);
459 /* Wait until the socket is ready */
463 FD_ZERO (&select_inset);
464 FD_SET (fd, &select_inset);
468 /*DEBUG(D_transport) debug_printf("waiting for data on fd\n");*/
469 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&select_inset, NULL, NULL, &tv);
471 /* If some interrupt arrived, just retry. We presume this to be rare,
472 but it can happen (e.g. the SIGUSR1 signal sent by exiwhat causes
475 Aug 2004: Somebody set up a cron job that ran exiwhat every 2 minutes, making
476 the interrupt not at all rare. Since the timeout is typically more than 2
477 minutes, the effect was to block the timeout completely. To prevent this
478 happening again, we do an explicit time test. */
480 if (rc < 0 && errno == EINTR)
482 DEBUG(D_transport) debug_printf("EINTR while waiting for socket data\n");
483 if (time(NULL) - start_recv < timeout) continue;
484 DEBUG(D_transport) debug_printf("total wait time exceeds timeout\n");
487 /* Handle a timeout, and treat any other select error as a timeout, including
488 an EINTR when we have been in this loop for longer than timeout. */
496 /* If the socket is ready, break out of the loop. */
498 if (FD_ISSET(fd, &select_inset)) break;
503 /* The timeout is implemented using select(), and we loop to cover select()
504 getting interrupted, and the possibility of select() returning with a positive
505 result but no ready descriptor. Is this in fact possible?
510 bufsize the buffer size
513 Returns: > 0 => that much data read
514 <= 0 on error or EOF; errno set - zero for EOF
518 ip_recv(int sock, uschar *buffer, int buffsize, int timeout)
522 if (!fd_ready(sock, timeout))
525 /* The socket is ready, read from it (via TLS if it's active). On EOF (i.e.
526 close down of the connection), set errno to zero; otherwise leave it alone. */
529 if (tls_out.active == sock)
530 rc = tls_read(FALSE, buffer, buffsize);
531 else if (tls_in.active == sock)
532 rc = tls_read(TRUE, buffer, buffsize);
535 rc = recv(sock, buffer, buffsize, 0);
537 if (rc > 0) return rc;
538 if (rc == 0) errno = 0;
545 /*************************************************
546 * Lookup address family of potential socket *
547 *************************************************/
549 /* Given a file-descriptor, check to see if it's a socket and, if so,
550 return the address family; detects IPv4 vs IPv6. If not a socket then
553 The value 0 is typically AF_UNSPEC, which should not be seen on a connected
554 fd. If the return is -1, the errno will be from getsockname(); probably
555 ENOTSOCK or ECONNRESET.
557 Arguments: socket-or-not fd
558 Returns: address family or -1
562 ip_get_address_family(int fd)
564 struct sockaddr_storage ss;
565 socklen_t sslen = sizeof(ss);
567 if (getsockname(fd, (struct sockaddr *) &ss, &sslen) < 0)
570 return (int) ss.ss_family;
576 /*************************************************
577 * Lookup DSCP settings for a socket *
578 *************************************************/
580 struct dscp_name_tableentry {
584 /* Keep both of these tables sorted! */
585 static struct dscp_name_tableentry dscp_table[] = {
586 #ifdef IPTOS_DSCP_AF11
587 { CUS"af11", IPTOS_DSCP_AF11 },
588 { CUS"af12", IPTOS_DSCP_AF12 },
589 { CUS"af13", IPTOS_DSCP_AF13 },
590 { CUS"af21", IPTOS_DSCP_AF21 },
591 { CUS"af22", IPTOS_DSCP_AF22 },
592 { CUS"af23", IPTOS_DSCP_AF23 },
593 { CUS"af31", IPTOS_DSCP_AF31 },
594 { CUS"af32", IPTOS_DSCP_AF32 },
595 { CUS"af33", IPTOS_DSCP_AF33 },
596 { CUS"af41", IPTOS_DSCP_AF41 },
597 { CUS"af42", IPTOS_DSCP_AF42 },
598 { CUS"af43", IPTOS_DSCP_AF43 },
599 { CUS"ef", IPTOS_DSCP_EF },
602 { CUS"lowcost", IPTOS_LOWCOST },
604 { CUS"lowdelay", IPTOS_LOWDELAY },
606 { CUS"mincost", IPTOS_MINCOST },
608 { CUS"reliability", IPTOS_RELIABILITY },
609 { CUS"throughput", IPTOS_THROUGHPUT }
611 static int dscp_table_size =
612 sizeof(dscp_table) / sizeof(struct dscp_name_tableentry);
614 /* DSCP values change by protocol family, and so do the options used for
615 setsockopt(); this utility does all the lookups. It takes an unexpanded
616 option string, expands it, strips off affix whitespace, then checks if it's
617 a number. If all of what's left is a number, then that's how the option will
618 be parsed and success/failure is a range check. If it's not all a number,
619 then it must be a supported keyword.
622 dscp_name a string, so far unvalidated
623 af address_family in use
624 level setsockopt level to use
625 optname setsockopt name to use
626 dscp_value value for dscp_name
628 Returns: TRUE if okay to setsockopt(), else FALSE
630 *level and *optname may be set even if FALSE is returned
634 dscp_lookup(const uschar *dscp_name, int af,
635 int *level, int *optname, int *dscp_value)
637 uschar *dscp_lookup, *p;
646 #if HAVE_IPV6 && defined(IPV6_TCLASS)
647 else if (af == AF_INET6)
649 *level = IPPROTO_IPV6;
650 *optname = IPV6_TCLASS;
656 debug_printf("Unhandled address family %d in dscp_lookup()\n", af);
662 debug_printf("[empty DSCP]\n");
665 dscp_lookup = expand_string(US dscp_name);
666 if (dscp_lookup == NULL || *dscp_lookup == '\0')
669 p = dscp_lookup + Ustrlen(dscp_lookup) - 1;
670 while (isspace(*p)) *p-- = '\0';
671 while (isspace(*dscp_lookup) && dscp_lookup < p) dscp_lookup++;
672 if (*dscp_lookup == '\0')
675 rawlong = Ustrtol(dscp_lookup, &p, 0);
676 if (p != dscp_lookup && *p == '\0')
678 /* We have six bits available, which will end up shifted to fit in 0xFC mask.
679 RFC 2597 defines the values unshifted. */
680 if (rawlong < 0 || rawlong > 0x3F)
683 debug_printf("DSCP value %ld out of range, ignored.\n", rawlong);
686 *dscp_value = rawlong << 2;
691 last = dscp_table_size;
694 int middle = (first + last)/2;
695 int c = Ustrcmp(dscp_lookup, dscp_table[middle].name);
698 *dscp_value = dscp_table[middle].value;
714 dscp_list_to_stream(FILE *stream)
717 for (i=0; i < dscp_table_size; ++i)
718 fprintf(stream, "%s\n", dscp_table[i].name);