1 /* Establishing and handling network connections.
2 Copyright (C) 1995, 1996, 1997, 2001, 2002 Free Software Foundation, Inc.
4 This file is part of GNU Wget.
6 GNU Wget is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 GNU Wget is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with Wget; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 In addition, as a special exception, the Free Software Foundation
21 gives permission to link the code of its release of Wget with the
22 OpenSSL project's "OpenSSL" library (or with modified versions of it
23 that use the same license as the "OpenSSL" library), and distribute
24 the linked executables. You must obey the GNU General Public License
25 in all respects for all of the code used other than "OpenSSL". If you
26 modify this file, you may extend this exception to your version of the
27 file, but you are not obligated to do so. If you do not wish to do
28 so, delete this exception statement from your version. */
34 #include <sys/types.h>
41 # include <sys/socket.h>
43 # include <netinet/in.h>
45 # include <arpa/inet.h>
47 #endif /* not WINDOWS */
54 #endif /* HAVE_STRING_H */
55 #ifdef HAVE_SYS_SELECT_H
56 # include <sys/select.h>
57 #endif /* HAVE_SYS_SELECT_H */
69 /* Define sockaddr_storage where unavailable (presumably on IPv4-only
73 # ifndef HAVE_STRUCT_SOCKADDR_STORAGE
74 # define sockaddr_storage sockaddr_in
76 #endif /* ENABLE_IPV6 */
78 /* Fill SA as per the data in IP and PORT. SA shoult point to struct
79 sockaddr_storage if ENABLE_IPV6 is defined, to struct sockaddr_in
83 sockaddr_set_data (struct sockaddr *sa, const ip_address *ip, int port)
89 struct sockaddr_in *sin = (struct sockaddr_in *)sa;
91 sin->sin_family = AF_INET;
92 sin->sin_port = htons (port);
93 sin->sin_addr = ADDRESS_IPV4_IN_ADDR (ip);
99 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
101 sin6->sin6_family = AF_INET6;
102 sin6->sin6_port = htons (port);
103 sin6->sin6_addr = ADDRESS_IPV6_IN6_ADDR (ip);
104 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
105 sin6->sin6_scope_id = ADDRESS_IPV6_SCOPE (ip);
109 #endif /* ENABLE_IPV6 */
115 /* Get the data of SA, specifically the IP address and the port. If
116 you're not interested in one or the other information, pass NULL as
120 sockaddr_get_data (const struct sockaddr *sa, ip_address *ip, int *port)
122 switch (sa->sa_family)
126 struct sockaddr_in *sin = (struct sockaddr_in *)sa;
129 ip->type = IPV4_ADDRESS;
130 ADDRESS_IPV4_IN_ADDR (ip) = sin->sin_addr;
133 *port = ntohs (sin->sin_port);
139 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
142 ip->type = IPV6_ADDRESS;
143 ADDRESS_IPV6_IN6_ADDR (ip) = sin6->sin6_addr;
144 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
145 ADDRESS_IPV6_SCOPE (ip) = sin6->sin6_scope_id;
149 *port = ntohs (sin6->sin6_port);
158 /* Return the size of the sockaddr structure depending on its
162 sockaddr_size (const struct sockaddr *sa)
164 switch (sa->sa_family)
167 return sizeof (struct sockaddr_in);
170 return sizeof (struct sockaddr_in6);
178 resolve_bind_address (struct sockaddr *sa)
180 struct address_list *al;
182 /* Make sure this is called only once. opt.bind_address doesn't
183 change during a Wget run. */
184 static int called, should_bind;
185 static ip_address ip;
189 sockaddr_set_data (sa, &ip, 0);
194 al = lookup_host (opt.bind_address, LH_BIND | LH_SILENT);
197 /* #### We should be able to print the error message here. */
198 logprintf (LOG_NOTQUIET,
199 _("%s: unable to resolve bind address `%s'; disabling bind.\n"),
200 exec_name, opt.bind_address);
205 /* Pick the first address in the list and use it as bind address.
206 Perhaps we should try multiple addresses in succession, but I
207 don't think that's necessary in practice. */
208 ip = *address_list_address_at (al, 0);
209 address_list_release (al);
211 sockaddr_set_data (sa, &ip, 0);
218 const struct sockaddr *addr;
224 connect_with_timeout_callback (void *arg)
226 struct cwt_context *ctx = (struct cwt_context *)arg;
227 ctx->result = connect (ctx->fd, ctx->addr, ctx->addrlen);
230 /* Like connect, but specifies a timeout. If connecting takes longer
231 than TIMEOUT seconds, -1 is returned and errno is set to
235 connect_with_timeout (int fd, const struct sockaddr *addr, socklen_t addrlen,
238 struct cwt_context ctx;
241 ctx.addrlen = addrlen;
243 if (run_with_timeout (timeout, connect_with_timeout_callback, &ctx))
248 if (ctx.result == -1 && errno == EINTR)
253 /* Connect via TCP to the specified address and port.
255 If PRINT is non-NULL, it is the host name to print that we're
259 connect_to_ip (const ip_address *ip, int port, const char *print)
261 struct sockaddr_storage ss;
262 struct sockaddr *sa = (struct sockaddr *)&ss;
265 /* If PRINT is non-NULL, print the "Connecting to..." line, with
266 PRINT being the host name we're connecting to. */
269 const char *txt_addr = pretty_print_address (ip);
270 if (print && 0 != strcmp (print, txt_addr))
271 logprintf (LOG_VERBOSE, _("Connecting to %s|%s|:%d... "),
272 escnonprint (print), txt_addr, port);
274 logprintf (LOG_VERBOSE, _("Connecting to %s:%d... "), txt_addr, port);
277 /* Store the sockaddr info to SA. */
278 sockaddr_set_data (sa, ip, port);
280 /* Create the socket of the family appropriate for the address. */
281 sock = socket (sa->sa_family, SOCK_STREAM, 0);
285 #if defined(ENABLE_IPV6) && defined(IPV6_V6ONLY)
288 /* In case of error, we will go on anyway... */
289 int err = setsockopt (sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on));
292 DEBUGP (("Failed setting IPV6_V6ONLY: %s", strerror (errno)));
297 /* For very small rate limits, set the buffer size (and hence,
298 hopefully, the kernel's TCP window size) to the per-second limit.
299 That way we should never have to sleep for more than 1s between
301 if (opt.limit_rate && opt.limit_rate < 8192)
303 int bufsize = opt.limit_rate;
305 bufsize = 512; /* avoid pathologically small values */
307 setsockopt (sock, SOL_SOCKET, SO_RCVBUF,
308 (void *)&bufsize, (socklen_t)sizeof (bufsize));
310 /* When we add limit_rate support for writing, which is useful
311 for POST, we should also set SO_SNDBUF here. */
314 if (opt.bind_address)
316 /* Bind the client side of the socket to the requested
318 struct sockaddr_storage bind_ss;
319 struct sockaddr *bind_sa = (struct sockaddr *)&bind_ss;
320 if (resolve_bind_address (bind_sa))
322 if (bind (sock, bind_sa, sockaddr_size (bind_sa)) < 0)
327 /* Connect the socket to the remote endpoint. */
328 if (connect_with_timeout (sock, sa, sockaddr_size (sa),
329 opt.connect_timeout) < 0)
335 logprintf (LOG_VERBOSE, _("connected.\n"));
336 DEBUGP (("Created socket %d.\n", sock));
341 /* Protect errno from possible modifications by close and
343 int save_errno = errno;
347 logprintf (LOG_VERBOSE, _("failed: %s.\n"), strerror (errno));
353 /* Connect via TCP to a remote host on the specified port.
355 HOST is resolved as an Internet host name. If HOST resolves to
356 more than one IP address, they are tried in the order returned by
357 DNS until connecting to one of them succeeds. */
360 connect_to_host (const char *host, int port)
365 struct address_list *al = lookup_host (host, 0);
371 address_list_get_bounds (al, &start, &end);
372 for (i = start; i < end; i++)
374 const ip_address *ip = address_list_address_at (al, i);
375 sock = connect_to_ip (ip, port, host);
379 address_list_set_connected (al);
380 address_list_release (al);
384 /* The attempt to connect has failed. Continue with the loop
385 and try next address. */
387 address_list_set_faulty (al, i);
390 /* Failed to connect to any of the addresses in AL. */
392 if (address_list_connected_p (al))
394 /* We connected to AL before, but cannot do so now. That might
395 indicate that our DNS cache entry for HOST has expired. */
396 address_list_release (al);
397 al = lookup_host (host, LH_REFRESH);
400 address_list_release (al);
405 /* Create a socket, bind it to local interface BIND_ADDRESS on port
406 *PORT, set up a listen backlog, and return the resulting socket, or
409 BIND_ADDRESS is the address of the interface to bind to. If it is
410 NULL, the socket is bound to the default address. PORT should
411 point to the port number that will be used for the binding. If
412 that number is 0, the system will choose a suitable port, and the
413 chosen value will be written to *PORT.
415 Calling accept() on such a socket waits for and accepts incoming
419 bind_local (const ip_address *bind_address, int *port)
422 int family = AF_INET;
423 struct sockaddr_storage ss;
424 struct sockaddr *sa = (struct sockaddr *)&ss;
426 /* For setting options with setsockopt. */
428 void *setopt_ptr = (void *)&setopt_val;
429 socklen_t setopt_size = sizeof (setopt_val);
432 if (bind_address->type == IPV6_ADDRESS)
436 sock = socket (family, SOCK_STREAM, 0);
441 setsockopt (sock, SOL_SOCKET, SO_REUSEADDR, setopt_ptr, setopt_size);
445 sockaddr_set_data (sa, bind_address, *port);
446 if (bind (sock, sa, sockaddr_size (sa)) < 0)
451 DEBUGP (("Local socket fd %d bound.\n", sock));
453 /* If *PORT is 0, find out which port we've bound to. */
456 socklen_t addrlen = sockaddr_size (sa);
457 if (getsockname (sock, sa, &addrlen) < 0)
459 /* If we can't find out the socket's local address ("name"),
460 something is seriously wrong with the socket, and it's
461 unusable for us anyway because we must know the chosen
466 sockaddr_get_data (sa, NULL, port);
467 DEBUGP (("binding to address %s using port %i.\n",
468 pretty_print_address (bind_address), *port));
470 if (listen (sock, 1) < 0)
478 /* Like a call to accept(), but with the added check for timeout.
480 In other words, accept a client connection on LOCAL_SOCK, and
481 return the new socket used for communication with the client.
482 LOCAL_SOCK should have been bound, e.g. using bind_local().
484 The caller is blocked until a connection is established. If no
485 connection is established for opt.connect_timeout seconds, the
486 function exits with an error status. */
489 accept_connection (int local_sock)
493 /* We don't need the values provided by accept, but accept
494 apparently requires them to be present. */
495 struct sockaddr_storage ss;
496 struct sockaddr *sa = (struct sockaddr *)&ss;
497 socklen_t addrlen = sizeof (ss);
499 if (opt.connect_timeout)
501 int test = select_fd (local_sock, opt.connect_timeout, WAIT_FOR_READ);
507 sock = accept (local_sock, sa, &addrlen);
508 DEBUGP (("Accepted client at socket %d.\n", sock));
512 /* Get the IP address associated with the connection on FD and store
513 it to IP. Return 1 on success, 0 otherwise.
515 If ENDPOINT is ENDPOINT_LOCAL, it returns the address of the local
516 (client) side of the socket. Else if ENDPOINT is ENDPOINT_PEER, it
517 returns the address of the remote (peer's) side of the socket. */
520 socket_ip_address (int sock, ip_address *ip, int endpoint)
522 struct sockaddr_storage storage;
523 struct sockaddr *sockaddr = (struct sockaddr *)&storage;
524 socklen_t addrlen = sizeof (storage);
527 if (endpoint == ENDPOINT_LOCAL)
528 ret = getsockname (sock, sockaddr, &addrlen);
529 else if (endpoint == ENDPOINT_PEER)
530 ret = getpeername (sock, sockaddr, &addrlen);
536 switch (sockaddr->sa_family)
541 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)&storage;
542 ip->type = IPV6_ADDRESS;
543 ADDRESS_IPV6_IN6_ADDR (ip) = sa6->sin6_addr;
544 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
545 ADDRESS_IPV6_SCOPE (ip) = sa6->sin6_scope_id;
547 DEBUGP (("conaddr is: %s\n", pretty_print_address (ip)));
553 struct sockaddr_in *sa = (struct sockaddr_in *)&storage;
554 ip->type = IPV4_ADDRESS;
555 ADDRESS_IPV4_IN_ADDR (ip) = sa->sin_addr;
556 DEBUGP (("conaddr is: %s\n", pretty_print_address (ip)));
564 /* Return non-zero if the error from the connect code can be
565 considered retryable. Wget normally retries after errors, but the
566 exception are the "unsupported protocol" type errors (possible on
567 IPv4/IPv6 dual family systems) and "connection refused". */
570 retryable_socket_connect_error (int err)
572 /* Have to guard against some of these values not being defined.
573 Cannot use a switch statement because some of the values might be
577 || err == EAFNOSUPPORT
580 || err == EPFNOSUPPORT
582 #ifdef ESOCKTNOSUPPORT /* no, "sockt" is not a typo! */
583 || err == ESOCKTNOSUPPORT
585 #ifdef EPROTONOSUPPORT
586 || err == EPROTONOSUPPORT
589 || err == ENOPROTOOPT
591 /* Apparently, older versions of Linux and BSD used EINVAL
592 instead of EAFNOSUPPORT and such. */
597 if (!opt.retry_connrefused)
598 if (err == ECONNREFUSED
600 || err == ENETUNREACH /* network is unreachable */
603 || err == EHOSTUNREACH /* host is unreachable */
611 /* Wait for a single descriptor to become available, timing out after
612 MAXTIME seconds. Returns 1 if FD is available, 0 for timeout and
613 -1 for error. The argument WAIT_FOR can be a combination of
614 WAIT_FOR_READ and WAIT_FOR_WRITE.
616 This is a mere convenience wrapper around the select call, and
617 should be taken as such (for example, it doesn't implement Wget's
618 0-timeout-means-no-timeout semantics.) */
621 select_fd (int fd, double maxtime, int wait_for)
625 fd_set *rd = NULL, *wr = NULL;
626 struct timeval tmout;
631 if (wait_for & WAIT_FOR_READ)
633 if (wait_for & WAIT_FOR_WRITE)
636 tmout.tv_sec = (long) maxtime;
637 tmout.tv_usec = 1000000 * (maxtime - (long) maxtime);
640 result = select (fd + 1, rd, wr, NULL, &tmout);
641 while (result < 0 && errno == EINTR);
645 #else /* not HAVE_SELECT */
647 /* If select() unavailable, just return 1. In most usages in Wget,
648 this is the appropriate response -- "if we can't poll, go ahead
649 with the blocking operation". If a specific part of code needs
650 different behavior, it can use #ifdef HAVE_SELECT to test whether
651 polling really occurs. */
654 #endif /* not HAVE_SELECT */
658 test_socket_open (int sock)
664 /* Check if we still have a valid (non-EOF) connection. From Andrew
665 * Maholski's code in the Unix Socket FAQ. */
667 FD_ZERO (&check_set);
668 FD_SET (sock, &check_set);
670 /* Wait one microsecond */
674 /* If we get a timeout, then that means still connected */
675 if (select (sock + 1, &check_set, NULL, NULL, &to) == 0)
677 /* Connection is valid (not EOF), so continue */
683 /* Without select, it's hard to know for sure. */
688 /* Basic socket operations, mostly EINTR wrappers. */
691 # define read(fd, buf, cnt) recv (fd, buf, cnt, 0)
692 # define write(fd, buf, cnt) send (fd, buf, cnt, 0)
693 # define close(fd) closesocket (fd)
697 # define read(fd, buf, cnt) recv (fd, buf, cnt, 0)
698 # define write(fd, buf, cnt) send (fd, buf, cnt, 0)
702 sock_read (int fd, char *buf, int bufsize)
706 res = read (fd, buf, bufsize);
707 while (res == -1 && errno == EINTR);
712 sock_write (int fd, char *buf, int bufsize)
716 res = write (fd, buf, bufsize);
717 while (res == -1 && errno == EINTR);
722 sock_poll (int fd, double timeout, int wait_for)
724 return select_fd (fd, timeout, wait_for);
728 sock_peek (int fd, char *buf, int bufsize)
732 res = recv (fd, buf, bufsize, MSG_PEEK);
733 while (res == -1 && errno == EINTR);
741 DEBUGP (("Closed fd %d\n", fd));
747 /* Reading and writing from the network. We build around the socket
748 (file descriptor) API, but support "extended" operations for things
749 that are not mere file descriptors under the hood, such as SSL
752 That way the user code can call fd_read(fd, ...) and we'll run read
753 or SSL_read or whatever is necessary. */
755 static struct hash_table *transport_map;
756 static int transport_map_modified_tick;
758 struct transport_info {
767 /* Register the transport layer operations that will be used when
768 reading, writing, and polling FD.
770 This should be used for transport layers like SSL that piggyback on
771 sockets. FD should otherwise be a real socket, on which you can
772 call getpeername, etc. */
775 fd_register_transport (int fd, fd_reader_t reader, fd_writer_t writer,
776 fd_poller_t poller, fd_peeker_t peeker,
777 fd_closer_t closer, void *ctx)
779 struct transport_info *info;
781 /* The file descriptor must be non-negative to be registered.
782 Negative values are ignored by fd_close(), and -1 cannot be used as
786 info = xnew (struct transport_info);
787 info->reader = reader;
788 info->writer = writer;
789 info->poller = poller;
790 info->peeker = peeker;
791 info->closer = closer;
794 transport_map = hash_table_new (0, NULL, NULL);
795 hash_table_put (transport_map, (void *) fd, info);
796 ++transport_map_modified_tick;
799 /* Return context of the transport registered with
800 fd_register_transport. This assumes fd_register_transport was
801 previously called on FD. */
804 fd_transport_context (int fd)
806 struct transport_info *info = hash_table_get (transport_map, (void *) fd);
810 /* When fd_read/fd_write are called multiple times in a loop, they should
811 remember the INFO pointer instead of fetching it every time. It is
812 not enough to compare FD to LAST_FD because FD might have been
813 closed and reopened. modified_tick ensures that changes to
814 transport_map will not be unnoticed.
816 This is a macro because we want the static storage variables to be
819 #define LAZY_RETRIEVE_INFO(info) do { \
820 static struct transport_info *last_info; \
821 static int last_fd = -1, last_tick; \
822 if (!transport_map) \
824 else if (last_fd == fd && last_tick == transport_map_modified_tick) \
828 info = hash_table_get (transport_map, (void *) fd); \
831 last_tick = transport_map_modified_tick; \
836 poll_internal (int fd, struct transport_info *info, int wf, double timeout)
839 timeout = opt.read_timeout;
843 if (info && info->poller)
844 test = info->poller (fd, timeout, wf, info->ctx);
846 test = sock_poll (fd, timeout, wf);
855 /* Read no more than BUFSIZE bytes of data from FD, storing them to
856 BUF. If TIMEOUT is non-zero, the operation aborts if no data is
857 received after that many seconds. If TIMEOUT is -1, the value of
858 opt.timeout is used for TIMEOUT. */
861 fd_read (int fd, char *buf, int bufsize, double timeout)
863 struct transport_info *info;
864 LAZY_RETRIEVE_INFO (info);
865 if (!poll_internal (fd, info, WAIT_FOR_READ, timeout))
867 if (info && info->reader)
868 return info->reader (fd, buf, bufsize, info->ctx);
870 return sock_read (fd, buf, bufsize);
873 /* Like fd_read, except it provides a "preview" of the data that will
874 be read by subsequent calls to fd_read. Specifically, it copies no
875 more than BUFSIZE bytes of the currently available data to BUF and
876 returns the number of bytes copied. Return values and timeout
877 semantics are the same as those of fd_read.
879 CAVEAT: Do not assume that the first subsequent call to fd_read
880 will retrieve the same amount of data. Reading can return more or
881 less data, depending on the TCP implementation and other
882 circumstances. However, barring an error, it can be expected that
883 all the peeked data will eventually be read by fd_read. */
886 fd_peek (int fd, char *buf, int bufsize, double timeout)
888 struct transport_info *info;
889 LAZY_RETRIEVE_INFO (info);
890 if (!poll_internal (fd, info, WAIT_FOR_READ, timeout))
892 if (info && info->peeker)
893 return info->peeker (fd, buf, bufsize, info->ctx);
895 return sock_peek (fd, buf, bufsize);
898 /* Write the entire contents of BUF to FD. If TIMEOUT is non-zero,
899 the operation aborts if no data is received after that many
900 seconds. If TIMEOUT is -1, the value of opt.timeout is used for
904 fd_write (int fd, char *buf, int bufsize, double timeout)
907 struct transport_info *info;
908 LAZY_RETRIEVE_INFO (info);
910 /* `write' may write less than LEN bytes, thus the loop keeps trying
911 it until all was written, or an error occurred. */
915 if (!poll_internal (fd, info, WAIT_FOR_WRITE, timeout))
917 if (info && info->writer)
918 res = info->writer (fd, buf, bufsize, info->ctx);
920 res = sock_write (fd, buf, bufsize);
929 /* Close the file descriptor FD. */
934 struct transport_info *info;
938 /* Don't use LAZY_RETRIEVE_INFO because fd_close() is only called once
939 per socket, so that particular optimization wouldn't work. */
942 info = hash_table_get (transport_map, (void *) fd);
944 if (info && info->closer)
945 info->closer (fd, info->ctx);
951 hash_table_remove (transport_map, (void *) fd);
953 ++transport_map_modified_tick;