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 3 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, visit the http://fsf.org website.
21 /* This file is now converted to use the new-style getaddrinfo()
22 * interface, which supports IPv6 but is also supported on recent
23 * IPv4-only machines. On systems that don't have that interface, we
24 * emulate it using the KAME implementation. */
27 #include <netinet/in_systm.h>
28 #include <netinet/ip.h>
29 #include <netinet/tcp.h>
31 extern char *bind_address;
32 extern int default_af_hint;
35 static struct sigaction sigact;
39 * Establish a proxy connection on an open socket to a web proxy by
40 * using the CONNECT method. If proxy_user and proxy_pass are not NULL,
41 * they are used to authenticate to the proxy using the "Basic"
42 * proxy-authorization protocol
44 static int establish_proxy_connection(int fd, char *host, int port,
45 char *proxy_user, char *proxy_pass)
47 char *cp, buffer[1024];
48 char *authhdr, authbuf[1024];
51 if (proxy_user && proxy_pass) {
52 stringjoin(buffer, sizeof buffer,
53 proxy_user, ":", proxy_pass, NULL);
56 if ((len*8 + 5) / 6 >= (int)sizeof authbuf - 3) {
58 "authentication information is too long\n");
62 base64_encode(buffer, len, authbuf, 1);
63 authhdr = "\r\nProxy-Authorization: Basic ";
69 snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",
70 host, port, authhdr, authbuf);
72 if (write(fd, buffer, len) != len) {
73 rsyserr(FERROR, errno, "failed to write to proxy");
77 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
78 if (read(fd, cp, 1) != 1) {
79 rsyserr(FERROR, errno, "failed to read from proxy");
91 if (strncmp(buffer, "HTTP/", 5) != 0) {
92 rprintf(FERROR, "bad response from proxy -- %s\n",
96 for (cp = &buffer[5]; isDigit(cp) || *cp == '.'; cp++) {}
100 rprintf(FERROR, "bad response from proxy -- %s\n",
104 /* throw away the rest of the HTTP header */
106 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
107 if (read(fd, cp, 1) != 1) {
108 rsyserr(FERROR, errno,
109 "failed to read from proxy");
115 if (cp > buffer && *cp == '\n')
117 if (cp == buffer && (*cp == '\n' || *cp == '\r'))
125 * Try to set the local address for a newly-created socket. Return -1
128 int try_bind_local(int s, int ai_family, int ai_socktype,
129 const char *bind_addr)
132 struct addrinfo bhints, *bres_all, *r;
134 memset(&bhints, 0, sizeof bhints);
135 bhints.ai_family = ai_family;
136 bhints.ai_socktype = ai_socktype;
137 bhints.ai_flags = AI_PASSIVE;
138 if ((error = getaddrinfo(bind_addr, NULL, &bhints, &bres_all))) {
139 rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
140 bind_addr, gai_strerror(error));
144 for (r = bres_all; r; r = r->ai_next) {
145 if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
147 freeaddrinfo(bres_all);
151 /* no error message; there might be some problem that allows
152 * creation of the socket but not binding, perhaps if the
153 * machine has no ipv6 address of this name. */
154 freeaddrinfo(bres_all);
160 * Open a socket to a tcp remote host with the specified port .
162 * Based on code from Warren. Proxy support by Stephen Rothwell.
163 * getaddrinfo() rewrite contributed by KAME.net.
165 * Now that we support IPv6 we need to look up the remote machine's
166 * address first, using @p af_hint to set a preference for the type
167 * of address. Then depending on whether it has v4 or v6 addresses we
168 * try to open a connection.
170 * The loop allows for machines with some addresses which may not be
171 * reachable, perhaps because we can't e.g. route ipv6 to that network
172 * but we can get ip4 packets through.
174 * @param bind_addr Local address to use. Normally NULL to bind
175 * the wildcard address.
177 * @param af_hint Address family, e.g. AF_INET or AF_INET6.
179 int open_socket_out(char *host, int port, const char *bind_addr,
182 int type = SOCK_STREAM;
184 struct addrinfo hints, *res0, *res;
189 char *proxy_user = NULL, *proxy_pass = NULL;
191 /* if we have a RSYNC_PROXY env variable then redirect our
192 * connetcion via a web proxy at the given address. */
193 h = getenv("RSYNC_PROXY");
194 proxied = h != NULL && *h != '\0';
197 strlcpy(buffer, h, sizeof buffer);
199 /* Is the USER:PASS@ prefix present? */
200 if ((cp = strrchr(buffer, '@')) != NULL) {
202 /* The remainder is the HOST:PORT part. */
205 if ((cp = strchr(buffer, ':')) == NULL) {
207 "invalid proxy specification: should be USER:PASS@HOST:PORT\n");
215 /* The whole buffer is the HOST:PORT part. */
219 if ((cp = strchr(h, ':')) == NULL) {
221 "invalid proxy specification: should be HOST:PORT\n");
225 strlcpy(portbuf, cp, sizeof portbuf);
227 rprintf(FINFO, "connection via http proxy %s port %s\n",
231 snprintf(portbuf, sizeof portbuf, "%d", port);
235 memset(&hints, 0, sizeof hints);
236 hints.ai_family = af_hint;
237 hints.ai_socktype = type;
238 error = getaddrinfo(h, portbuf, &hints, &res0);
240 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
241 h, portbuf, gai_strerror(error));
246 /* Try to connect to all addresses for this machine until we get
247 * through. It might e.g. be multi-homed, or have both IPv4 and IPv6
248 * addresses. We need to create a socket for each record, since the
249 * address record tells us what protocol to use to try to connect. */
250 for (res = res0; res; res = res->ai_next) {
251 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
256 && try_bind_local(s, res->ai_family, type,
262 if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
268 && establish_proxy_connection(s, host, port,
269 proxy_user, proxy_pass) != 0) {
278 rsyserr(FERROR, errno, "failed to connect to %s", h);
286 * Open an outgoing socket, but allow for it to be intercepted by
287 * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
288 * socketpair rather than really opening a socket.
290 * We use this primarily in testing to detect TCP flow bugs, but not
291 * cause security problems by really opening remote connections.
293 * This is based on the Samba LIBSMB_PROG feature.
295 * @param bind_addr Local address to use. Normally NULL to get the stack default.
297 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
300 char *prog = getenv("RSYNC_CONNECT_PROG");
303 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
304 prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
308 return sock_exec(prog);
309 return open_socket_out(host, port, bind_addr, af_hint);
315 * Open one or more sockets for incoming data using the specified type,
318 * The getaddrinfo() call may return several address results, e.g. for
319 * the machine's IPv4 and IPv6 name.
321 * We return an array of file-descriptors to the sockets, with a trailing
322 * -1 value to indicate the end of the list.
324 * @param bind_addr Local address to bind, or NULL to allow it to
327 static int *open_socket_in(int type, int port, const char *bind_addr,
331 int s, *socks, maxs, i, ecnt;
332 struct addrinfo hints, *all_ai, *resp;
333 char portbuf[10], **errmsgs;
336 memset(&hints, 0, sizeof hints);
337 hints.ai_family = af_hint;
338 hints.ai_socktype = type;
339 hints.ai_flags = AI_PASSIVE;
340 snprintf(portbuf, sizeof portbuf, "%d", port);
341 error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
343 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
344 bind_addr, gai_strerror(error));
348 /* Count max number of sockets we might open. */
349 for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
351 socks = new_array(int, maxs + 1);
352 errmsgs = new_array(char *, maxs);
353 if (!socks || !errmsgs)
354 out_of_memory("open_socket_in");
356 /* We may not be able to create the socket, if for example the
357 * machine knows about IPv6 in the C library, but not in the
359 for (resp = all_ai, i = ecnt = 0; resp; resp = resp->ai_next) {
360 s = socket(resp->ai_family, resp->ai_socktype,
364 int r = asprintf(&errmsgs[ecnt++],
365 "socket(%d,%d,%d) failed: %s\n",
366 (int)resp->ai_family, (int)resp->ai_socktype,
367 (int)resp->ai_protocol, strerror(errno));
369 out_of_memory("open_socket_in");
370 /* See if there's another address that will work... */
374 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
375 (char *)&one, sizeof one);
378 if (resp->ai_family == AF_INET6) {
379 if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
380 (char *)&one, sizeof one) < 0
381 && default_af_hint != AF_INET6) {
388 /* Now we've got a socket - we need to bind it. */
389 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
390 /* Nope, try another */
391 int r = asprintf(&errmsgs[ecnt++],
392 "bind() failed: %s (address-family %d)\n",
393 strerror(errno), (int)resp->ai_family);
395 out_of_memory("open_socket_in");
405 freeaddrinfo(all_ai);
407 /* Only output the socket()/bind() messages if we were totally
408 * unsuccessful, or if the daemon is being run with -vv. */
409 for (s = 0; s < ecnt; s++) {
410 if (!i || verbose > 1)
411 rwrite(FLOG, errmsgs[s], strlen(errmsgs[s]), 0);
418 "unable to bind any inbound sockets on port %d\n",
428 * Determine if a file descriptor is in fact a socket
430 int is_a_socket(int fd)
433 socklen_t l = sizeof (int);
435 /* Parameters to getsockopt, setsockopt etc are very
436 * unstandardized across platforms, so don't be surprised if
437 * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
438 * It seems they all eventually get the right idea.
440 * Debian says: ``The fifth argument of getsockopt and
441 * setsockopt is in reality an int [*] (and this is what BSD
442 * 4.* and libc4 and libc5 have). Some POSIX confusion
443 * resulted in the present socklen_t. The draft standard has
444 * not been adopted yet, but glibc2 already follows it and
445 * also has socklen_t [*]. See also accept(2).''
447 * We now return to your regularly scheduled programming. */
448 return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
452 static RETSIGTYPE sigchld_handler(UNUSED(int val))
455 while (waitpid(-1, NULL, WNOHANG) > 0) {}
457 #ifndef HAVE_SIGACTION
458 signal(SIGCHLD, sigchld_handler);
463 void start_accept_loop(int port, int (*fn)(int, int))
468 #ifdef HAVE_SIGACTION
469 sigact.sa_flags = SA_NOCLDSTOP;
472 /* open an incoming socket */
473 sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
475 exit_cleanup(RERR_SOCKETIO);
477 /* ready to listen */
479 for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
480 if (listen(sp[i], 5) < 0) {
481 rsyserr(FERROR, errno, "listen() on socket failed");
483 if (errno == EADDRINUSE && i > 0) {
485 "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
488 exit_cleanup(RERR_SOCKETIO);
490 FD_SET(sp[i], &deffds);
495 /* now accept incoming connections - forking a new process
496 * for each incoming connection */
501 struct sockaddr_storage addr;
502 socklen_t addrlen = sizeof addr;
504 /* close log file before the potentially very long select so
505 * file can be trimmed by another process instead of growing
510 FD_COPY(&deffds, &fds);
515 if (select(maxfd + 1, &fds, NULL, NULL, NULL) != 1)
518 for (i = 0, fd = -1; sp[i] >= 0; i++) {
519 if (FD_ISSET(sp[i], &fds)) {
520 fd = accept(sp[i], (struct sockaddr *)&addr,
529 SIGACTION(SIGCHLD, sigchld_handler);
531 if ((pid = fork()) == 0) {
533 for (i = 0; sp[i] >= 0; i++)
535 /* Re-open log file in child before possibly giving
536 * up privileges (see logfile_close() above). */
541 } else if (pid < 0) {
542 rsyserr(FERROR, errno,
543 "could not create child server process");
545 /* This might have happened because we're
546 * overloaded. Sleep briefly before trying to
550 /* Parent doesn't need this fd anymore. */
557 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
566 } socket_options[] = {
567 {"SO_KEEPALIVE", SOL_SOCKET, SO_KEEPALIVE, 0, OPT_BOOL},
568 {"SO_REUSEADDR", SOL_SOCKET, SO_REUSEADDR, 0, OPT_BOOL},
569 {"SO_BROADCAST", SOL_SOCKET, SO_BROADCAST, 0, OPT_BOOL},
571 {"TCP_NODELAY", IPPROTO_TCP, TCP_NODELAY, 0, OPT_BOOL},
573 #ifdef IPTOS_LOWDELAY
574 {"IPTOS_LOWDELAY", IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY, OPT_ON},
576 #ifdef IPTOS_THROUGHPUT
577 {"IPTOS_THROUGHPUT", IPPROTO_IP, IP_TOS, IPTOS_THROUGHPUT, OPT_ON},
580 {"SO_SNDBUF", SOL_SOCKET, SO_SNDBUF, 0, OPT_INT},
583 {"SO_RCVBUF", SOL_SOCKET, SO_RCVBUF, 0, OPT_INT},
586 {"SO_SNDLOWAT", SOL_SOCKET, SO_SNDLOWAT, 0, OPT_INT},
589 {"SO_RCVLOWAT", SOL_SOCKET, SO_RCVLOWAT, 0, OPT_INT},
592 {"SO_SNDTIMEO", SOL_SOCKET, SO_SNDTIMEO, 0, OPT_INT},
595 {"SO_RCVTIMEO", SOL_SOCKET, SO_RCVTIMEO, 0, OPT_INT},
602 * Set user socket options
604 void set_socket_options(int fd, char *options)
608 if (!options || !*options)
611 options = strdup(options);
614 out_of_memory("set_socket_options");
616 for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
622 if ((p = strchr(tok,'='))) {
628 for (i = 0; socket_options[i].name; i++) {
629 if (strcmp(socket_options[i].name,tok)==0)
633 if (!socket_options[i].name) {
634 rprintf(FERROR,"Unknown socket option %s\n",tok);
638 switch (socket_options[i].opttype) {
641 ret = setsockopt(fd,socket_options[i].level,
642 socket_options[i].option,
643 (char *)&value, sizeof (int));
648 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
651 int on = socket_options[i].value;
652 ret = setsockopt(fd,socket_options[i].level,
653 socket_options[i].option,
654 (char *)&on, sizeof (int));
660 rsyserr(FERROR, errno,
661 "failed to set socket option %s", tok);
669 * Become a daemon, discarding the controlling terminal
671 void become_daemon(void)
679 /* detach from the terminal */
682 #elif defined TIOCNOTTY
683 i = open("/dev/tty", O_RDWR);
685 ioctl(i, (int)TIOCNOTTY, (char *)0);
689 /* make sure that stdin, stdout an stderr don't stuff things
690 * up (library functions, for example) */
691 for (i = 0; i < 3; i++) {
693 open("/dev/null", O_RDWR);
699 * This is like socketpair but uses tcp. It is used by the Samba
700 * regression test code.
702 * The function guarantees that nobody else can attach to the socket,
703 * or if they do that this function fails and the socket gets closed
704 * returns 0 on success, -1 on failure the resulting file descriptors
707 static int socketpair_tcp(int fd[2])
710 struct sockaddr_in sock;
711 struct sockaddr_in sock2;
712 socklen_t socklen = sizeof sock;
713 int connect_done = 0;
715 fd[0] = fd[1] = listener = -1;
717 memset(&sock, 0, sizeof sock);
719 if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
722 memset(&sock2, 0, sizeof sock2);
723 #ifdef HAVE_SOCKADDR_IN_LEN
724 sock2.sin_len = sizeof sock2;
726 sock2.sin_family = PF_INET;
728 bind(listener, (struct sockaddr *)&sock2, sizeof sock2);
730 if (listen(listener, 1) != 0)
733 if (getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0)
736 if ((fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1)
739 set_nonblocking(fd[1]);
741 sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
743 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) == -1) {
744 if (errno != EINPROGRESS)
749 if ((fd[0] = accept(listener, (struct sockaddr *)&sock, &socklen)) == -1)
757 if (connect_done == 0) {
758 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
779 * Run a program on a local tcp socket, so that we can talk to it's
780 * stdin and stdout. This is used to fake a connection to a daemon
781 * for testing -- not for the normal case of running SSH.
783 * @return a socket which is attached to a subprocess running
784 * "prog". stdin and stdout are attached. stderr is left attached to
785 * the original stderr
787 int sock_exec(const char *prog)
791 if (socketpair_tcp(fd) != 0) {
792 rsyserr(FERROR, errno, "socketpair_tcp failed");
796 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);