2 * Socket functions used in rsync.
4 * Copyright (C) 1992-2001 Andrew Tridgell <tridge@samba.org>
5 * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
6 * Copyright (C) 2003-2007 Wayne Davison
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
22 /* This file is now converted to use the new-style getaddrinfo()
23 * interface, which supports IPv6 but is also supported on recent
24 * IPv4-only machines. On systems that don't have that interface, we
25 * emulate it using the KAME implementation. */
28 #include <netinet/in_systm.h>
29 #include <netinet/ip.h>
30 #include <netinet/tcp.h>
32 extern char *bind_address;
33 extern int default_af_hint;
36 static struct sigaction sigact;
40 * Establish a proxy connection on an open socket to a web proxy by
41 * using the CONNECT method. If proxy_user and proxy_pass are not NULL,
42 * they are used to authenticate to the proxy using the "Basic"
43 * proxy-authorization protocol
45 static int establish_proxy_connection(int fd, char *host, int port,
46 char *proxy_user, char *proxy_pass)
48 char *cp, buffer[1024];
49 char *authhdr, authbuf[1024];
52 if (proxy_user && proxy_pass) {
53 stringjoin(buffer, sizeof buffer,
54 proxy_user, ":", proxy_pass, NULL);
57 if ((len*8 + 5) / 6 >= (int)sizeof authbuf - 3) {
59 "authentication information is too long\n");
63 base64_encode(buffer, len, authbuf, 1);
64 authhdr = "\r\nProxy-Authorization: Basic ";
70 snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",
71 host, port, authhdr, authbuf);
73 if (write(fd, buffer, len) != len) {
74 rsyserr(FERROR, errno, "failed to write to proxy");
78 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
79 if (read(fd, cp, 1) != 1) {
80 rsyserr(FERROR, errno, "failed to read from proxy");
92 if (strncmp(buffer, "HTTP/", 5) != 0) {
93 rprintf(FERROR, "bad response from proxy -- %s\n",
97 for (cp = &buffer[5]; isDigit(cp) || *cp == '.'; cp++) {}
101 rprintf(FERROR, "bad response from proxy -- %s\n",
105 /* throw away the rest of the HTTP header */
107 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
108 if (read(fd, cp, 1) != 1) {
109 rsyserr(FERROR, errno,
110 "failed to read from proxy");
116 if (cp > buffer && *cp == '\n')
118 if (cp == buffer && (*cp == '\n' || *cp == '\r'))
126 * Try to set the local address for a newly-created socket. Return -1
129 int try_bind_local(int s, int ai_family, int ai_socktype,
130 const char *bind_addr)
133 struct addrinfo bhints, *bres_all, *r;
135 memset(&bhints, 0, sizeof bhints);
136 bhints.ai_family = ai_family;
137 bhints.ai_socktype = ai_socktype;
138 bhints.ai_flags = AI_PASSIVE;
139 if ((error = getaddrinfo(bind_addr, NULL, &bhints, &bres_all))) {
140 rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
141 bind_addr, gai_strerror(error));
145 for (r = bres_all; r; r = r->ai_next) {
146 if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
148 freeaddrinfo(bres_all);
152 /* no error message; there might be some problem that allows
153 * creation of the socket but not binding, perhaps if the
154 * machine has no ipv6 address of this name. */
155 freeaddrinfo(bres_all);
161 * Open a socket to a tcp remote host with the specified port .
163 * Based on code from Warren. Proxy support by Stephen Rothwell.
164 * getaddrinfo() rewrite contributed by KAME.net.
166 * Now that we support IPv6 we need to look up the remote machine's
167 * address first, using @p af_hint to set a preference for the type
168 * of address. Then depending on whether it has v4 or v6 addresses we
169 * try to open a connection.
171 * The loop allows for machines with some addresses which may not be
172 * reachable, perhaps because we can't e.g. route ipv6 to that network
173 * but we can get ip4 packets through.
175 * @param bind_addr Local address to use. Normally NULL to bind
176 * the wildcard address.
178 * @param af_hint Address family, e.g. AF_INET or AF_INET6.
180 int open_socket_out(char *host, int port, const char *bind_addr,
183 int type = SOCK_STREAM;
185 struct addrinfo hints, *res0, *res;
190 char *proxy_user = NULL, *proxy_pass = NULL;
192 /* if we have a RSYNC_PROXY env variable then redirect our
193 * connetcion via a web proxy at the given address. */
194 h = getenv("RSYNC_PROXY");
195 proxied = h != NULL && *h != '\0';
198 strlcpy(buffer, h, sizeof buffer);
200 /* Is the USER:PASS@ prefix present? */
201 if ((cp = strrchr(buffer, '@')) != NULL) {
203 /* The remainder is the HOST:PORT part. */
206 if ((cp = strchr(buffer, ':')) == NULL) {
208 "invalid proxy specification: should be USER:PASS@HOST:PORT\n");
216 /* The whole buffer is the HOST:PORT part. */
220 if ((cp = strchr(h, ':')) == NULL) {
222 "invalid proxy specification: should be HOST:PORT\n");
226 strlcpy(portbuf, cp, sizeof portbuf);
228 rprintf(FINFO, "connection via http proxy %s port %s\n",
232 snprintf(portbuf, sizeof portbuf, "%d", port);
236 memset(&hints, 0, sizeof hints);
237 hints.ai_family = af_hint;
238 hints.ai_socktype = type;
239 error = getaddrinfo(h, portbuf, &hints, &res0);
241 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
242 h, portbuf, gai_strerror(error));
247 /* Try to connect to all addresses for this machine until we get
248 * through. It might e.g. be multi-homed, or have both IPv4 and IPv6
249 * addresses. We need to create a socket for each record, since the
250 * address record tells us what protocol to use to try to connect. */
251 for (res = res0; res; res = res->ai_next) {
252 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
257 && try_bind_local(s, res->ai_family, type,
263 if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
269 && establish_proxy_connection(s, host, port,
270 proxy_user, proxy_pass) != 0) {
279 rsyserr(FERROR, errno, "failed to connect to %s", h);
287 * Open an outgoing socket, but allow for it to be intercepted by
288 * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
289 * socketpair rather than really opening a socket.
291 * We use this primarily in testing to detect TCP flow bugs, but not
292 * cause security problems by really opening remote connections.
294 * This is based on the Samba LIBSMB_PROG feature.
296 * @param bind_addr Local address to use. Normally NULL to get the stack default.
298 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
301 char *prog = getenv("RSYNC_CONNECT_PROG");
304 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
305 prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
309 return sock_exec(prog);
310 return open_socket_out(host, port, bind_addr, af_hint);
316 * Open one or more sockets for incoming data using the specified type,
319 * The getaddrinfo() call may return several address results, e.g. for
320 * the machine's IPv4 and IPv6 name.
322 * We return an array of file-descriptors to the sockets, with a trailing
323 * -1 value to indicate the end of the list.
325 * @param bind_addr Local address to bind, or NULL to allow it to
328 static int *open_socket_in(int type, int port, const char *bind_addr,
332 int s, *socks, maxs, i, ecnt;
333 struct addrinfo hints, *all_ai, *resp;
334 char portbuf[10], **errmsgs;
337 memset(&hints, 0, sizeof hints);
338 hints.ai_family = af_hint;
339 hints.ai_socktype = type;
340 hints.ai_flags = AI_PASSIVE;
341 snprintf(portbuf, sizeof portbuf, "%d", port);
342 error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
344 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
345 bind_addr, gai_strerror(error));
349 /* Count max number of sockets we might open. */
350 for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
352 socks = new_array(int, maxs + 1);
353 errmsgs = new_array(char *, maxs);
354 if (!socks || !errmsgs)
355 out_of_memory("open_socket_in");
357 /* We may not be able to create the socket, if for example the
358 * machine knows about IPv6 in the C library, but not in the
360 for (resp = all_ai, i = ecnt = 0; resp; resp = resp->ai_next) {
361 s = socket(resp->ai_family, resp->ai_socktype,
365 int r = asprintf(&errmsgs[ecnt++],
366 "socket(%d,%d,%d) failed: %s\n",
367 (int)resp->ai_family, (int)resp->ai_socktype,
368 (int)resp->ai_protocol, strerror(errno));
370 out_of_memory("open_socket_in");
371 /* See if there's another address that will work... */
375 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
376 (char *)&one, sizeof one);
379 if (resp->ai_family == AF_INET6) {
380 if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
381 (char *)&one, sizeof one) < 0
382 && default_af_hint != AF_INET6) {
389 /* Now we've got a socket - we need to bind it. */
390 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
391 /* Nope, try another */
392 int r = asprintf(&errmsgs[ecnt++],
393 "bind() failed: %s (address-family %d)\n",
394 strerror(errno), (int)resp->ai_family);
396 out_of_memory("open_socket_in");
406 freeaddrinfo(all_ai);
408 /* Only output the socket()/bind() messages if we were totally
409 * unsuccessful, or if the daemon is being run with -vv. */
410 for (s = 0; s < ecnt; s++) {
411 if (!i || verbose > 1)
412 rwrite(FLOG, errmsgs[s], strlen(errmsgs[s]));
419 "unable to bind any inbound sockets on port %d\n",
429 * Determine if a file descriptor is in fact a socket
431 int is_a_socket(int fd)
434 socklen_t l = sizeof (int);
436 /* Parameters to getsockopt, setsockopt etc are very
437 * unstandardized across platforms, so don't be surprised if
438 * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
439 * It seems they all eventually get the right idea.
441 * Debian says: ``The fifth argument of getsockopt and
442 * setsockopt is in reality an int [*] (and this is what BSD
443 * 4.* and libc4 and libc5 have). Some POSIX confusion
444 * resulted in the present socklen_t. The draft standard has
445 * not been adopted yet, but glibc2 already follows it and
446 * also has socklen_t [*]. See also accept(2).''
448 * We now return to your regularly scheduled programming. */
449 return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
453 static RETSIGTYPE sigchld_handler(UNUSED(int val))
456 while (waitpid(-1, NULL, WNOHANG) > 0) {}
458 #ifndef HAVE_SIGACTION
459 signal(SIGCHLD, sigchld_handler);
464 void start_accept_loop(int port, int (*fn)(int, int))
469 #ifdef HAVE_SIGACTION
470 sigact.sa_flags = SA_NOCLDSTOP;
473 /* open an incoming socket */
474 sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
476 exit_cleanup(RERR_SOCKETIO);
478 /* ready to listen */
480 for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
481 if (listen(sp[i], 5) < 0) {
482 rsyserr(FERROR, errno, "listen() on socket failed");
484 if (errno == EADDRINUSE && i > 0) {
486 "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
489 exit_cleanup(RERR_SOCKETIO);
491 FD_SET(sp[i], &deffds);
496 /* now accept incoming connections - forking a new process
497 * for each incoming connection */
502 struct sockaddr_storage addr;
503 socklen_t addrlen = sizeof addr;
505 /* close log file before the potentially very long select so
506 * file can be trimmed by another process instead of growing
511 FD_COPY(&deffds, &fds);
516 if (select(maxfd + 1, &fds, NULL, NULL, NULL) != 1)
519 for (i = 0, fd = -1; sp[i] >= 0; i++) {
520 if (FD_ISSET(sp[i], &fds)) {
521 fd = accept(sp[i], (struct sockaddr *)&addr,
530 SIGACTION(SIGCHLD, sigchld_handler);
532 if ((pid = fork()) == 0) {
534 for (i = 0; sp[i] >= 0; i++)
536 /* Re-open log file in child before possibly giving
537 * up privileges (see logfile_close() above). */
542 } else if (pid < 0) {
543 rsyserr(FERROR, errno,
544 "could not create child server process");
546 /* This might have happened because we're
547 * overloaded. Sleep briefly before trying to
551 /* Parent doesn't need this fd anymore. */
558 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
567 } socket_options[] = {
568 {"SO_KEEPALIVE", SOL_SOCKET, SO_KEEPALIVE, 0, OPT_BOOL},
569 {"SO_REUSEADDR", SOL_SOCKET, SO_REUSEADDR, 0, OPT_BOOL},
570 {"SO_BROADCAST", SOL_SOCKET, SO_BROADCAST, 0, OPT_BOOL},
572 {"TCP_NODELAY", IPPROTO_TCP, TCP_NODELAY, 0, OPT_BOOL},
574 #ifdef IPTOS_LOWDELAY
575 {"IPTOS_LOWDELAY", IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY, OPT_ON},
577 #ifdef IPTOS_THROUGHPUT
578 {"IPTOS_THROUGHPUT", IPPROTO_IP, IP_TOS, IPTOS_THROUGHPUT, OPT_ON},
581 {"SO_SNDBUF", SOL_SOCKET, SO_SNDBUF, 0, OPT_INT},
584 {"SO_RCVBUF", SOL_SOCKET, SO_RCVBUF, 0, OPT_INT},
587 {"SO_SNDLOWAT", SOL_SOCKET, SO_SNDLOWAT, 0, OPT_INT},
590 {"SO_RCVLOWAT", SOL_SOCKET, SO_RCVLOWAT, 0, OPT_INT},
593 {"SO_SNDTIMEO", SOL_SOCKET, SO_SNDTIMEO, 0, OPT_INT},
596 {"SO_RCVTIMEO", SOL_SOCKET, SO_RCVTIMEO, 0, OPT_INT},
603 * Set user socket options
605 void set_socket_options(int fd, char *options)
609 if (!options || !*options)
612 options = strdup(options);
615 out_of_memory("set_socket_options");
617 for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
623 if ((p = strchr(tok,'='))) {
629 for (i = 0; socket_options[i].name; i++) {
630 if (strcmp(socket_options[i].name,tok)==0)
634 if (!socket_options[i].name) {
635 rprintf(FERROR,"Unknown socket option %s\n",tok);
639 switch (socket_options[i].opttype) {
642 ret = setsockopt(fd,socket_options[i].level,
643 socket_options[i].option,
644 (char *)&value, sizeof (int));
649 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
652 int on = socket_options[i].value;
653 ret = setsockopt(fd,socket_options[i].level,
654 socket_options[i].option,
655 (char *)&on, sizeof (int));
661 rsyserr(FERROR, errno,
662 "failed to set socket option %s", tok);
670 * Become a daemon, discarding the controlling terminal
672 void become_daemon(void)
680 /* detach from the terminal */
683 #elif defined TIOCNOTTY
684 i = open("/dev/tty", O_RDWR);
686 ioctl(i, (int)TIOCNOTTY, (char *)0);
690 /* make sure that stdin, stdout an stderr don't stuff things
691 * up (library functions, for example) */
692 for (i = 0; i < 3; i++) {
694 open("/dev/null", O_RDWR);
700 * This is like socketpair but uses tcp. It is used by the Samba
701 * regression test code.
703 * The function guarantees that nobody else can attach to the socket,
704 * or if they do that this function fails and the socket gets closed
705 * returns 0 on success, -1 on failure the resulting file descriptors
708 static int socketpair_tcp(int fd[2])
711 struct sockaddr_in sock;
712 struct sockaddr_in sock2;
713 socklen_t socklen = sizeof sock;
714 int connect_done = 0;
716 fd[0] = fd[1] = listener = -1;
718 memset(&sock, 0, sizeof sock);
720 if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
723 memset(&sock2, 0, sizeof sock2);
724 #ifdef HAVE_SOCKADDR_IN_LEN
725 sock2.sin_len = sizeof sock2;
727 sock2.sin_family = PF_INET;
729 bind(listener, (struct sockaddr *)&sock2, sizeof sock2);
731 if (listen(listener, 1) != 0)
734 if (getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0)
737 if ((fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1)
740 set_nonblocking(fd[1]);
742 sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
744 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) == -1) {
745 if (errno != EINPROGRESS)
750 if ((fd[0] = accept(listener, (struct sockaddr *)&sock, &socklen)) == -1)
758 if (connect_done == 0) {
759 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
780 * Run a program on a local tcp socket, so that we can talk to it's
781 * stdin and stdout. This is used to fake a connection to a daemon
782 * for testing -- not for the normal case of running SSH.
784 * @return a socket which is attached to a subprocess running
785 * "prog". stdin and stdout are attached. stderr is left attached to
786 * the original stderr
788 int sock_exec(const char *prog)
792 if (socketpair_tcp(fd) != 0) {
793 rsyserr(FERROR, errno, "socketpair_tcp failed");
797 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);