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) 2003-2009 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 3 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, visit the http://fsf.org website.
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. */
29 #include <netinet/in_systm.h>
30 #include <netinet/ip.h>
31 #include <netinet/tcp.h>
33 extern char *bind_address;
34 extern char *sockopts;
35 extern int default_af_hint;
36 extern int connect_timeout;
39 static struct sigaction sigact;
42 static int sock_exec(const char *prog);
44 /* Establish a proxy connection on an open socket to a web proxy by using the
45 * CONNECT method. If proxy_user and proxy_pass are not NULL, they are used to
46 * authenticate to the proxy using the "Basic" proxy-authorization protocol. */
47 static int establish_proxy_connection(int fd, char *host, int port,
48 char *proxy_user, char *proxy_pass)
50 char *cp, buffer[1024];
51 char *authhdr, authbuf[1024];
54 if (proxy_user && proxy_pass) {
55 stringjoin(buffer, sizeof buffer,
56 proxy_user, ":", proxy_pass, NULL);
59 if ((len*8 + 5) / 6 >= (int)sizeof authbuf - 3) {
61 "authentication information is too long\n");
65 base64_encode(buffer, len, authbuf, 1);
66 authhdr = "\r\nProxy-Authorization: Basic ";
72 snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",
73 host, port, authhdr, authbuf);
75 if (write(fd, buffer, len) != len) {
76 rsyserr(FERROR, errno, "failed to write to proxy");
80 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
81 if (read(fd, cp, 1) != 1) {
82 rsyserr(FERROR, errno, "failed to read from proxy");
94 if (strncmp(buffer, "HTTP/", 5) != 0) {
95 rprintf(FERROR, "bad response from proxy -- %s\n",
99 for (cp = &buffer[5]; isDigit(cp) || *cp == '.'; cp++) {}
103 rprintf(FERROR, "bad response from proxy -- %s\n",
107 /* throw away the rest of the HTTP header */
109 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
110 if (read(fd, cp, 1) != 1) {
111 rsyserr(FERROR, errno,
112 "failed to read from proxy");
118 if (cp > buffer && *cp == '\n')
120 if (cp == buffer && (*cp == '\n' || *cp == '\r'))
127 /* Try to set the local address for a newly-created socket.
128 * Return -1 if this fails. */
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);
159 /* connect() timeout handler based on alarm() */
160 static RETSIGTYPE contimeout_handler(UNUSED(int val))
162 connect_timeout = -1;
165 /* Open a socket to a tcp remote host with the specified port.
167 * Based on code from Warren. Proxy support by Stephen Rothwell.
168 * getaddrinfo() rewrite contributed by KAME.net.
170 * Now that we support IPv6 we need to look up the remote machine's address
171 * first, using af_hint to set a preference for the type of address. Then
172 * depending on whether it has v4 or v6 addresses we try to open a connection.
174 * The loop allows for machines with some addresses which may not be reachable,
175 * perhaps because we can't e.g. route ipv6 to that network but we can get ip4
178 * bind_addr: local address to use. Normally NULL to bind the wildcard address.
180 * 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;
185 int error, s, j, addr_cnt, *errnos;
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);
228 if (DEBUG_GTE(CONNECT, 1)) {
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));
247 for (res = res0, addr_cnt = 0; res; res = res->ai_next, addr_cnt++) {}
248 errnos = new_array0(int, addr_cnt);
250 out_of_memory("open_socket_out");
253 /* Try to connect to all addresses for this machine until we get
254 * through. It might e.g. be multi-homed, or have both IPv4 and IPv6
255 * addresses. We need to create a socket for each record, since the
256 * address record tells us what protocol to use to try to connect. */
257 for (res = res0, j = 0; res; res = res->ai_next, j++) {
258 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
263 && try_bind_local(s, res->ai_family, type,
269 if (connect_timeout > 0) {
270 SIGACTION(SIGALRM, contimeout_handler);
271 alarm(connect_timeout);
274 set_socket_options(s, sockopts);
275 while (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
276 if (connect_timeout < 0)
277 exit_cleanup(RERR_CONTIMEOUT);
285 if (connect_timeout > 0)
294 && establish_proxy_connection(s, host, port,
295 proxy_user, proxy_pass) != 0) {
300 if (DEBUG_GTE(CONNECT, 2)) {
302 if ((error = getnameinfo(res->ai_addr, res->ai_addrlen, buf, sizeof buf, NULL, 0, NI_NUMERICHOST) != 0))
303 rprintf(FINFO, "error in getnameinfo: %s\n", gai_strerror(error));
305 rprintf(FINFO, "Connected to %s (%s)\n", h, buf);
310 if (s < 0 || DEBUG_GTE(CONNECT, 2)) {
312 for (res = res0, j = 0; res; res = res->ai_next, j++) {
315 if (inet_ntop(res->ai_family, res->ai_addr->sa_data + 2, buf, sizeof buf) == NULL)
316 strlcpy(buf, "*inet_ntop failed*", sizeof buf);
317 rsyserr(FERROR, errnos[j], "failed to connect to %s (%s)", h, buf);
330 /* Open an outgoing socket, but allow for it to be intercepted by
331 * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
332 * socketpair rather than really opening a socket.
334 * We use this primarily in testing to detect TCP flow bugs, but not
335 * cause security problems by really opening remote connections.
337 * This is based on the Samba LIBSMB_PROG feature.
339 * bind_addr: local address to use. Normally NULL to get the stack default. */
340 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
343 char *prog = getenv("RSYNC_CONNECT_PROG");
345 if (prog && strchr(prog, '%')) {
346 int hlen = strlen(host);
347 int len = strlen(prog) + 1;
349 for (f = prog; *f; f++) {
352 /* Compute more than enough room. */
359 if (!(prog = new_array(char, len)))
360 out_of_memory("open_socket_out_wrapped");
361 for (t = prog; *f; f++) {
365 /* Just skips the extra '%'. */
368 memcpy(t, host, hlen);
372 f--; /* pass % through */
381 if (DEBUG_GTE(CONNECT, 1)) {
382 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
383 prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
387 return sock_exec(prog);
388 return open_socket_out(host, port, bind_addr, af_hint);
392 /* Open one or more sockets for incoming data using the specified type,
395 * The getaddrinfo() call may return several address results, e.g. for
396 * the machine's IPv4 and IPv6 name.
398 * We return an array of file-descriptors to the sockets, with a trailing
399 * -1 value to indicate the end of the list.
401 * bind_addr: local address to bind, or NULL to allow it to default. */
402 static int *open_socket_in(int type, int port, const char *bind_addr,
406 int s, *socks, maxs, i, ecnt;
407 struct addrinfo hints, *all_ai, *resp;
408 char portbuf[10], **errmsgs;
411 memset(&hints, 0, sizeof hints);
412 hints.ai_family = af_hint;
413 hints.ai_socktype = type;
414 hints.ai_flags = AI_PASSIVE;
415 snprintf(portbuf, sizeof portbuf, "%d", port);
416 error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
418 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
419 bind_addr, gai_strerror(error));
423 /* Count max number of sockets we might open. */
424 for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
426 socks = new_array(int, maxs + 1);
427 errmsgs = new_array(char *, maxs);
428 if (!socks || !errmsgs)
429 out_of_memory("open_socket_in");
431 /* We may not be able to create the socket, if for example the
432 * machine knows about IPv6 in the C library, but not in the
434 for (resp = all_ai, i = ecnt = 0; resp; resp = resp->ai_next) {
435 s = socket(resp->ai_family, resp->ai_socktype,
439 int r = asprintf(&errmsgs[ecnt++],
440 "socket(%d,%d,%d) failed: %s\n",
441 (int)resp->ai_family, (int)resp->ai_socktype,
442 (int)resp->ai_protocol, strerror(errno));
444 out_of_memory("open_socket_in");
445 /* See if there's another address that will work... */
449 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
450 (char *)&one, sizeof one);
452 set_socket_options(s, sockopts);
454 set_socket_options(s, lp_socket_options());
457 if (resp->ai_family == AF_INET6) {
458 if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
459 (char *)&one, sizeof one) < 0
460 && default_af_hint != AF_INET6) {
467 /* Now we've got a socket - we need to bind it. */
468 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
469 /* Nope, try another */
470 int r = asprintf(&errmsgs[ecnt++],
471 "bind() failed: %s (address-family %d)\n",
472 strerror(errno), (int)resp->ai_family);
474 out_of_memory("open_socket_in");
484 freeaddrinfo(all_ai);
486 /* Only output the socket()/bind() messages if we were totally
487 * unsuccessful, or if the daemon is being run with -vv. */
488 for (s = 0; s < ecnt; s++) {
489 if (!i || DEBUG_GTE(BIND, 1))
490 rwrite(FLOG, errmsgs[s], strlen(errmsgs[s]), 0);
497 "unable to bind any inbound sockets on port %d\n",
506 /* Determine if a file descriptor is in fact a socket. */
507 int is_a_socket(int fd)
510 socklen_t l = sizeof (int);
512 /* Parameters to getsockopt, setsockopt etc are very
513 * unstandardized across platforms, so don't be surprised if
514 * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
515 * It seems they all eventually get the right idea.
517 * Debian says: ``The fifth argument of getsockopt and
518 * setsockopt is in reality an int [*] (and this is what BSD
519 * 4.* and libc4 and libc5 have). Some POSIX confusion
520 * resulted in the present socklen_t. The draft standard has
521 * not been adopted yet, but glibc2 already follows it and
522 * also has socklen_t [*]. See also accept(2).''
524 * We now return to your regularly scheduled programming. */
525 return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
529 static RETSIGTYPE sigchld_handler(UNUSED(int val))
532 while (waitpid(-1, NULL, WNOHANG) > 0) {}
534 #ifndef HAVE_SIGACTION
535 signal(SIGCHLD, sigchld_handler);
540 void start_accept_loop(int port, int (*fn)(int, int))
545 #ifdef HAVE_SIGACTION
546 sigact.sa_flags = SA_NOCLDSTOP;
549 /* open an incoming socket */
550 sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
552 exit_cleanup(RERR_SOCKETIO);
554 /* ready to listen */
556 for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
557 if (listen(sp[i], lp_listen_backlog()) < 0) {
558 rsyserr(FERROR, errno, "listen() on socket failed");
560 if (errno == EADDRINUSE && i > 0) {
562 "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
565 exit_cleanup(RERR_SOCKETIO);
567 FD_SET(sp[i], &deffds);
572 /* now accept incoming connections - forking a new process
573 * for each incoming connection */
578 struct sockaddr_storage addr;
579 socklen_t addrlen = sizeof addr;
581 /* close log file before the potentially very long select so
582 * file can be trimmed by another process instead of growing
587 FD_COPY(&deffds, &fds);
592 if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 1)
595 for (i = 0, fd = -1; sp[i] >= 0; i++) {
596 if (FD_ISSET(sp[i], &fds)) {
597 fd = accept(sp[i], (struct sockaddr *)&addr,
606 SIGACTION(SIGCHLD, sigchld_handler);
608 if ((pid = fork()) == 0) {
610 for (i = 0; sp[i] >= 0; i++)
612 /* Re-open log file in child before possibly giving
613 * up privileges (see logfile_close() above). */
618 } else if (pid < 0) {
619 rsyserr(FERROR, errno,
620 "could not create child server process");
622 /* This might have happened because we're
623 * overloaded. Sleep briefly before trying to
627 /* Parent doesn't need this fd anymore. */
634 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
643 } socket_options[] = {
644 {"SO_KEEPALIVE", SOL_SOCKET, SO_KEEPALIVE, 0, OPT_BOOL},
645 {"SO_REUSEADDR", SOL_SOCKET, SO_REUSEADDR, 0, OPT_BOOL},
646 {"SO_BROADCAST", SOL_SOCKET, SO_BROADCAST, 0, OPT_BOOL},
648 {"TCP_NODELAY", IPPROTO_TCP, TCP_NODELAY, 0, OPT_BOOL},
650 #ifdef IPTOS_LOWDELAY
651 {"IPTOS_LOWDELAY", IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY, OPT_ON},
653 #ifdef IPTOS_THROUGHPUT
654 {"IPTOS_THROUGHPUT", IPPROTO_IP, IP_TOS, IPTOS_THROUGHPUT, OPT_ON},
657 {"SO_SNDBUF", SOL_SOCKET, SO_SNDBUF, 0, OPT_INT},
660 {"SO_RCVBUF", SOL_SOCKET, SO_RCVBUF, 0, OPT_INT},
663 {"SO_SNDLOWAT", SOL_SOCKET, SO_SNDLOWAT, 0, OPT_INT},
666 {"SO_RCVLOWAT", SOL_SOCKET, SO_RCVLOWAT, 0, OPT_INT},
669 {"SO_SNDTIMEO", SOL_SOCKET, SO_SNDTIMEO, 0, OPT_INT},
672 {"SO_RCVTIMEO", SOL_SOCKET, SO_RCVTIMEO, 0, OPT_INT},
678 /* Set user socket options. */
679 void set_socket_options(int fd, char *options)
683 if (!options || !*options)
686 options = strdup(options);
689 out_of_memory("set_socket_options");
691 for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
697 if ((p = strchr(tok,'='))) {
703 for (i = 0; socket_options[i].name; i++) {
704 if (strcmp(socket_options[i].name,tok)==0)
708 if (!socket_options[i].name) {
709 rprintf(FERROR,"Unknown socket option %s\n",tok);
713 switch (socket_options[i].opttype) {
716 ret = setsockopt(fd,socket_options[i].level,
717 socket_options[i].option,
718 (char *)&value, sizeof (int));
723 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
726 int on = socket_options[i].value;
727 ret = setsockopt(fd,socket_options[i].level,
728 socket_options[i].option,
729 (char *)&on, sizeof (int));
735 rsyserr(FERROR, errno,
736 "failed to set socket option %s", tok);
744 /* This is like socketpair but uses tcp. The function guarantees that nobody
745 * else can attach to the socket, or if they do that this function fails and
746 * the socket gets closed. Returns 0 on success, -1 on failure. The resulting
747 * file descriptors are symmetrical. Currently only for RSYNC_CONNECT_PROG. */
748 static int socketpair_tcp(int fd[2])
751 struct sockaddr_in sock;
752 struct sockaddr_in sock2;
753 socklen_t socklen = sizeof sock;
754 int connect_done = 0;
756 fd[0] = fd[1] = listener = -1;
758 memset(&sock, 0, sizeof sock);
760 if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
763 memset(&sock2, 0, sizeof sock2);
764 #ifdef HAVE_SOCKADDR_IN_LEN
765 sock2.sin_len = sizeof sock2;
767 sock2.sin_family = PF_INET;
768 sock2.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
770 if (bind(listener, (struct sockaddr *)&sock2, sizeof sock2) != 0
771 || listen(listener, 1) != 0
772 || getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0
773 || (fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1)
776 set_nonblocking(fd[1]);
778 sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
780 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) == -1) {
781 if (errno != EINPROGRESS)
786 if ((fd[0] = accept(listener, (struct sockaddr *)&sock2, &socklen)) == -1)
794 if (connect_done == 0) {
795 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
814 /* Run a program on a local tcp socket, so that we can talk to it's stdin and
815 * stdout. This is used to fake a connection to a daemon for testing -- not
816 * for the normal case of running SSH.
818 * Retruns a socket which is attached to a subprocess running "prog". stdin and
819 * stdout are attached. stderr is left attached to the original stderr. */
820 static int sock_exec(const char *prog)
825 if (socketpair_tcp(fd) != 0) {
826 rsyserr(FERROR, errno, "socketpair_tcp failed");
829 if (DEBUG_GTE(CMD, 1))
830 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);
834 rsyserr(FERROR, errno, "fork");
835 exit_cleanup(RERR_IPC);
840 if (dup2(fd[1], STDIN_FILENO) < 0
841 || dup2(fd[1], STDOUT_FILENO) < 0) {
842 fprintf(stderr, "Failed to run \"%s\"\n", prog);