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, 2004, 2005, 2006 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 as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
23 /* This file is now converted to use the new-style getaddrinfo()
24 * interface, which supports IPv6 but is also supported on recent
25 * IPv4-only machines. On systems that don't have that interface, we
26 * emulate it using the KAME implementation. */
29 #include <netinet/in_systm.h>
30 #include <netinet/ip.h>
31 #include <netinet/tcp.h>
33 extern char *bind_address;
34 extern int default_af_hint;
37 static struct sigaction sigact;
41 * Establish a proxy connection on an open socket to a web proxy by
42 * using the CONNECT method. If proxy_user and proxy_pass are not NULL,
43 * they are used to authenticate to the proxy using the "Basic"
44 * proxy-authorization protocol
46 static int establish_proxy_connection(int fd, char *host, int port,
47 char *proxy_user, char *proxy_pass)
49 char *cp, buffer[1024];
50 char *authhdr, authbuf[1024];
53 if (proxy_user && proxy_pass) {
54 stringjoin(buffer, sizeof buffer,
55 proxy_user, ":", proxy_pass, NULL);
58 if ((len*8 + 5) / 6 >= (int)sizeof authbuf - 3) {
60 "authentication information is too long\n");
64 base64_encode(buffer, len, authbuf, 1);
65 authhdr = "\r\nProxy-Authorization: Basic ";
71 snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",
72 host, port, authhdr, authbuf);
74 if (write(fd, buffer, len) != len) {
75 rsyserr(FERROR, errno, "failed to write to proxy");
79 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
80 if (read(fd, cp, 1) != 1) {
81 rsyserr(FERROR, errno, "failed to read from proxy");
93 if (strncmp(buffer, "HTTP/", 5) != 0) {
94 rprintf(FERROR, "bad response from proxy -- %s\n",
98 for (cp = &buffer[5]; isdigit(*(uchar*)cp) || *cp == '.'; cp++) {}
102 rprintf(FERROR, "bad response from proxy -- %s\n",
106 /* throw away the rest of the HTTP header */
108 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
109 if (read(fd, cp, 1) != 1) {
110 rsyserr(FERROR, errno,
111 "failed to read from proxy");
117 if (cp > buffer && *cp == '\n')
119 if (cp == buffer && (*cp == '\n' || *cp == '\r'))
127 * Try to set the local address for a newly-created socket. Return -1
130 int try_bind_local(int s, int ai_family, int ai_socktype,
131 const char *bind_addr)
134 struct addrinfo bhints, *bres_all, *r;
136 memset(&bhints, 0, sizeof bhints);
137 bhints.ai_family = ai_family;
138 bhints.ai_socktype = ai_socktype;
139 bhints.ai_flags = AI_PASSIVE;
140 if ((error = getaddrinfo(bind_addr, NULL, &bhints, &bres_all))) {
141 rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
142 bind_addr, gai_strerror(error));
146 for (r = bres_all; r; r = r->ai_next) {
147 if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
149 freeaddrinfo(bres_all);
153 /* no error message; there might be some problem that allows
154 * creation of the socket but not binding, perhaps if the
155 * machine has no ipv6 address of this name. */
156 freeaddrinfo(bres_all);
162 * Open a socket to a tcp remote host with the specified port .
164 * Based on code from Warren. Proxy support by Stephen Rothwell.
165 * getaddrinfo() rewrite contributed by KAME.net.
167 * Now that we support IPv6 we need to look up the remote machine's
168 * address first, using @p af_hint to set a preference for the type
169 * of address. Then depending on whether it has v4 or v6 addresses we
170 * try to open a connection.
172 * The loop allows for machines with some addresses which may not be
173 * reachable, perhaps because we can't e.g. route ipv6 to that network
174 * but we can get ip4 packets through.
176 * @param bind_addr Local address to use. Normally NULL to bind
177 * the wildcard address.
179 * @param af_hint Address family, e.g. AF_INET or AF_INET6.
181 int open_socket_out(char *host, int port, const char *bind_addr,
184 int type = SOCK_STREAM;
186 struct addrinfo hints, *res0, *res;
191 char *proxy_user = NULL, *proxy_pass = NULL;
193 /* if we have a RSYNC_PROXY env variable then redirect our
194 * connetcion via a web proxy at the given address. */
195 h = getenv("RSYNC_PROXY");
196 proxied = h != NULL && *h != '\0';
199 strlcpy(buffer, h, sizeof buffer);
201 /* Is the USER:PASS@ prefix present? */
202 if ((cp = strrchr(buffer, '@')) != NULL) {
204 /* The remainder is the HOST:PORT part. */
207 if ((cp = strchr(buffer, ':')) == NULL) {
209 "invalid proxy specification: should be USER:PASS@HOST:PORT\n");
217 /* The whole buffer is the HOST:PORT part. */
221 if ((cp = strchr(h, ':')) == NULL) {
223 "invalid proxy specification: should be HOST:PORT\n");
227 strlcpy(portbuf, cp, sizeof portbuf);
229 rprintf(FINFO, "connection via http proxy %s port %s\n",
233 snprintf(portbuf, sizeof portbuf, "%d", port);
237 memset(&hints, 0, sizeof hints);
238 hints.ai_family = af_hint;
239 hints.ai_socktype = type;
240 error = getaddrinfo(h, portbuf, &hints, &res0);
242 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
243 h, portbuf, gai_strerror(error));
248 /* Try to connect to all addresses for this machine until we get
249 * through. It might e.g. be multi-homed, or have both IPv4 and IPv6
250 * addresses. We need to create a socket for each record, since the
251 * address record tells us what protocol to use to try to connect. */
252 for (res = res0; res; res = res->ai_next) {
253 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
258 && try_bind_local(s, res->ai_family, type,
264 if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
270 && establish_proxy_connection(s, host, port,
271 proxy_user, proxy_pass) != 0) {
280 rsyserr(FERROR, errno, "failed to connect to %s", h);
288 * Open an outgoing socket, but allow for it to be intercepted by
289 * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
290 * socketpair rather than really opening a socket.
292 * We use this primarily in testing to detect TCP flow bugs, but not
293 * cause security problems by really opening remote connections.
295 * This is based on the Samba LIBSMB_PROG feature.
297 * @param bind_addr Local address to use. Normally NULL to get the stack default.
299 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
302 char *prog = getenv("RSYNC_CONNECT_PROG");
305 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
306 prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
310 return sock_exec(prog);
311 return open_socket_out(host, port, bind_addr, af_hint);
317 * Open one or more sockets for incoming data using the specified type,
320 * The getaddrinfo() call may return several address results, e.g. for
321 * the machine's IPv4 and IPv6 name.
323 * We return an array of file-descriptors to the sockets, with a trailing
324 * -1 value to indicate the end of the list.
326 * @param bind_addr Local address to bind, or NULL to allow it to
329 static int *open_socket_in(int type, int port, const char *bind_addr,
333 int s, *socks, maxs, i, ecnt;
334 struct addrinfo hints, *all_ai, *resp;
335 char portbuf[10], **errmsgs;
338 memset(&hints, 0, sizeof hints);
339 hints.ai_family = af_hint;
340 hints.ai_socktype = type;
341 hints.ai_flags = AI_PASSIVE;
342 snprintf(portbuf, sizeof portbuf, "%d", port);
343 error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
345 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
346 bind_addr, gai_strerror(error));
350 /* Count max number of sockets we might open. */
351 for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
353 socks = new_array(int, maxs + 1);
354 errmsgs = new_array(char *, maxs);
355 if (!socks || !errmsgs)
356 out_of_memory("open_socket_in");
358 /* We may not be able to create the socket, if for example the
359 * machine knows about IPv6 in the C library, but not in the
361 for (resp = all_ai, i = ecnt = 0; resp; resp = resp->ai_next) {
362 s = socket(resp->ai_family, resp->ai_socktype,
366 int r = asprintf(&errmsgs[ecnt++],
367 "socket(%d,%d,%d) failed: %s\n",
368 (int)resp->ai_family, (int)resp->ai_socktype,
369 (int)resp->ai_protocol, strerror(errno));
371 out_of_memory("open_socket_in");
372 /* See if there's another address that will work... */
376 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
377 (char *)&one, sizeof one);
380 if (resp->ai_family == AF_INET6) {
381 if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
382 (char *)&one, sizeof one) < 0
383 && default_af_hint != AF_INET6) {
390 /* Now we've got a socket - we need to bind it. */
391 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
392 /* Nope, try another */
393 int r = asprintf(&errmsgs[ecnt++],
394 "bind() failed: %s (address-family %d)\n",
395 strerror(errno), (int)resp->ai_family);
397 out_of_memory("open_socket_in");
407 freeaddrinfo(all_ai);
409 /* Only output the socket()/bind() messages if we were totally
410 * unsuccessful, or if the daemon is being run with -vv. */
411 for (s = 0; s < ecnt; s++) {
412 if (!i || verbose > 1)
413 rwrite(FLOG, errmsgs[s], strlen(errmsgs[s]));
420 "unable to bind any inbound sockets on port %d\n",
430 * Determine if a file descriptor is in fact a socket
432 int is_a_socket(int fd)
435 socklen_t l = sizeof (int);
437 /* Parameters to getsockopt, setsockopt etc are very
438 * unstandardized across platforms, so don't be surprised if
439 * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
440 * It seems they all eventually get the right idea.
442 * Debian says: ``The fifth argument of getsockopt and
443 * setsockopt is in reality an int [*] (and this is what BSD
444 * 4.* and libc4 and libc5 have). Some POSIX confusion
445 * resulted in the present socklen_t. The draft standard has
446 * not been adopted yet, but glibc2 already follows it and
447 * also has socklen_t [*]. See also accept(2).''
449 * We now return to your regularly scheduled programming. */
450 return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
454 static RETSIGTYPE sigchld_handler(UNUSED(int val))
457 while (waitpid(-1, NULL, WNOHANG) > 0) {}
459 #ifndef HAVE_SIGACTION
460 signal(SIGCHLD, sigchld_handler);
465 void start_accept_loop(int port, int (*fn)(int, int))
470 #ifdef HAVE_SIGACTION
471 sigact.sa_flags = SA_NOCLDSTOP;
474 /* open an incoming socket */
475 sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
477 exit_cleanup(RERR_SOCKETIO);
479 /* ready to listen */
481 for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
482 if (listen(sp[i], 5) < 0) {
483 rsyserr(FERROR, errno, "listen() on socket failed");
485 if (errno == EADDRINUSE && i > 0) {
487 "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
490 exit_cleanup(RERR_SOCKETIO);
492 FD_SET(sp[i], &deffds);
497 /* now accept incoming connections - forking a new process
498 * for each incoming connection */
503 struct sockaddr_storage addr;
504 socklen_t addrlen = sizeof addr;
506 /* close log file before the potentially very long select so
507 * file can be trimmed by another process instead of growing
512 FD_COPY(&deffds, &fds);
517 if (select(maxfd + 1, &fds, NULL, NULL, NULL) != 1)
520 for (i = 0, fd = -1; sp[i] >= 0; i++) {
521 if (FD_ISSET(sp[i], &fds)) {
522 fd = accept(sp[i], (struct sockaddr *)&addr,
531 SIGACTION(SIGCHLD, sigchld_handler);
533 if ((pid = fork()) == 0) {
535 for (i = 0; sp[i] >= 0; i++)
537 /* Re-open log file in child before possibly giving
538 * up privileges (see logfile_close() above). */
543 } else if (pid < 0) {
544 rsyserr(FERROR, errno,
545 "could not create child server process");
547 /* This might have happened because we're
548 * overloaded. Sleep briefly before trying to
552 /* Parent doesn't need this fd anymore. */
559 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
568 } socket_options[] = {
569 {"SO_KEEPALIVE", SOL_SOCKET, SO_KEEPALIVE, 0, OPT_BOOL},
570 {"SO_REUSEADDR", SOL_SOCKET, SO_REUSEADDR, 0, OPT_BOOL},
571 {"SO_BROADCAST", SOL_SOCKET, SO_BROADCAST, 0, OPT_BOOL},
573 {"TCP_NODELAY", IPPROTO_TCP, TCP_NODELAY, 0, OPT_BOOL},
575 #ifdef IPTOS_LOWDELAY
576 {"IPTOS_LOWDELAY", IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY, OPT_ON},
578 #ifdef IPTOS_THROUGHPUT
579 {"IPTOS_THROUGHPUT", IPPROTO_IP, IP_TOS, IPTOS_THROUGHPUT, OPT_ON},
582 {"SO_SNDBUF", SOL_SOCKET, SO_SNDBUF, 0, OPT_INT},
585 {"SO_RCVBUF", SOL_SOCKET, SO_RCVBUF, 0, OPT_INT},
588 {"SO_SNDLOWAT", SOL_SOCKET, SO_SNDLOWAT, 0, OPT_INT},
591 {"SO_RCVLOWAT", SOL_SOCKET, SO_RCVLOWAT, 0, OPT_INT},
594 {"SO_SNDTIMEO", SOL_SOCKET, SO_SNDTIMEO, 0, OPT_INT},
597 {"SO_RCVTIMEO", SOL_SOCKET, SO_RCVTIMEO, 0, OPT_INT},
604 * Set user socket options
606 void set_socket_options(int fd, char *options)
610 if (!options || !*options)
613 options = strdup(options);
616 out_of_memory("set_socket_options");
618 for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
624 if ((p = strchr(tok,'='))) {
630 for (i = 0; socket_options[i].name; i++) {
631 if (strcmp(socket_options[i].name,tok)==0)
635 if (!socket_options[i].name) {
636 rprintf(FERROR,"Unknown socket option %s\n",tok);
640 switch (socket_options[i].opttype) {
643 ret = setsockopt(fd,socket_options[i].level,
644 socket_options[i].option,
645 (char *)&value, sizeof (int));
650 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
653 int on = socket_options[i].value;
654 ret = setsockopt(fd,socket_options[i].level,
655 socket_options[i].option,
656 (char *)&on, sizeof (int));
662 rsyserr(FERROR, errno,
663 "failed to set socket option %s", tok);
671 * Become a daemon, discarding the controlling terminal
673 void become_daemon(void)
681 /* detach from the terminal */
684 #elif defined TIOCNOTTY
685 i = open("/dev/tty", O_RDWR);
687 ioctl(i, (int)TIOCNOTTY, (char *)0);
691 /* make sure that stdin, stdout an stderr don't stuff things
692 * up (library functions, for example) */
693 for (i = 0; i < 3; i++) {
695 open("/dev/null", O_RDWR);
701 * This is like socketpair but uses tcp. It is used by the Samba
702 * regression test code.
704 * The function guarantees that nobody else can attach to the socket,
705 * or if they do that this function fails and the socket gets closed
706 * returns 0 on success, -1 on failure the resulting file descriptors
709 static int socketpair_tcp(int fd[2])
712 struct sockaddr_in sock;
713 struct sockaddr_in sock2;
714 socklen_t socklen = sizeof sock;
715 int connect_done = 0;
717 fd[0] = fd[1] = listener = -1;
719 memset(&sock, 0, sizeof sock);
721 if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
724 memset(&sock2, 0, sizeof sock2);
725 #ifdef HAVE_SOCKADDR_IN_LEN
726 sock2.sin_len = sizeof sock2;
728 sock2.sin_family = PF_INET;
730 bind(listener, (struct sockaddr *)&sock2, sizeof sock2);
732 if (listen(listener, 1) != 0)
735 if (getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0)
738 if ((fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1)
741 set_nonblocking(fd[1]);
743 sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
745 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) == -1) {
746 if (errno != EINPROGRESS)
751 if ((fd[0] = accept(listener, (struct sockaddr *)&sock, &socklen)) == -1)
759 if (connect_done == 0) {
760 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
781 * Run a program on a local tcp socket, so that we can talk to it's
782 * stdin and stdout. This is used to fake a connection to a daemon
783 * for testing -- not for the normal case of running SSH.
785 * @return a socket which is attached to a subprocess running
786 * "prog". stdin and stdout are attached. stderr is left attached to
787 * the original stderr
789 int sock_exec(const char *prog)
793 if (socketpair_tcp(fd) != 0) {
794 rsyserr(FERROR, errno, "socketpair_tcp failed");
798 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);