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) 2003-2008 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 int default_af_hint;
35 extern int connect_timeout;
38 static struct sigaction sigact;
42 * Establish a proxy connection on an open socket to a web proxy by
43 * using the CONNECT method. If proxy_user and proxy_pass are not NULL,
44 * they are used to authenticate to the proxy using the "Basic"
45 * 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'))
128 * Try to set the local address for a newly-created socket. Return -1
131 int try_bind_local(int s, int ai_family, int ai_socktype,
132 const char *bind_addr)
135 struct addrinfo bhints, *bres_all, *r;
137 memset(&bhints, 0, sizeof bhints);
138 bhints.ai_family = ai_family;
139 bhints.ai_socktype = ai_socktype;
140 bhints.ai_flags = AI_PASSIVE;
141 if ((error = getaddrinfo(bind_addr, NULL, &bhints, &bres_all))) {
142 rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
143 bind_addr, gai_strerror(error));
147 for (r = bres_all; r; r = r->ai_next) {
148 if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
150 freeaddrinfo(bres_all);
154 /* no error message; there might be some problem that allows
155 * creation of the socket but not binding, perhaps if the
156 * machine has no ipv6 address of this name. */
157 freeaddrinfo(bres_all);
161 /* connect() timeout handler based on alarm() */
162 static RETSIGTYPE contimeout_handler(UNUSED(int val))
164 connect_timeout = -1;
168 * Open a socket to a tcp remote host with the specified port .
170 * Based on code from Warren. Proxy support by Stephen Rothwell.
171 * getaddrinfo() rewrite contributed by KAME.net.
173 * Now that we support IPv6 we need to look up the remote machine's
174 * address first, using @p af_hint to set a preference for the type
175 * of address. Then depending on whether it has v4 or v6 addresses we
176 * try to open a connection.
178 * The loop allows for machines with some addresses which may not be
179 * reachable, perhaps because we can't e.g. route ipv6 to that network
180 * but we can get ip4 packets through.
182 * @param bind_addr Local address to use. Normally NULL to bind
183 * the wildcard address.
185 * @param af_hint Address family, e.g. AF_INET or AF_INET6.
187 int open_socket_out(char *host, int port, const char *bind_addr,
190 int type = SOCK_STREAM;
192 struct addrinfo hints, *res0, *res;
197 char *proxy_user = NULL, *proxy_pass = NULL;
199 /* if we have a RSYNC_PROXY env variable then redirect our
200 * connetcion via a web proxy at the given address. */
201 h = getenv("RSYNC_PROXY");
202 proxied = h != NULL && *h != '\0';
205 strlcpy(buffer, h, sizeof buffer);
207 /* Is the USER:PASS@ prefix present? */
208 if ((cp = strrchr(buffer, '@')) != NULL) {
210 /* The remainder is the HOST:PORT part. */
213 if ((cp = strchr(buffer, ':')) == NULL) {
215 "invalid proxy specification: should be USER:PASS@HOST:PORT\n");
223 /* The whole buffer is the HOST:PORT part. */
227 if ((cp = strchr(h, ':')) == NULL) {
229 "invalid proxy specification: should be HOST:PORT\n");
233 strlcpy(portbuf, cp, sizeof portbuf);
235 rprintf(FINFO, "connection via http proxy %s port %s\n",
239 snprintf(portbuf, sizeof portbuf, "%d", port);
243 memset(&hints, 0, sizeof hints);
244 hints.ai_family = af_hint;
245 hints.ai_socktype = type;
246 error = getaddrinfo(h, portbuf, &hints, &res0);
248 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
249 h, portbuf, gai_strerror(error));
254 /* Try to connect to all addresses for this machine until we get
255 * through. It might e.g. be multi-homed, or have both IPv4 and IPv6
256 * addresses. We need to create a socket for each record, since the
257 * address record tells us what protocol to use to try to connect. */
258 for (res = res0; res; res = res->ai_next) {
259 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
264 && try_bind_local(s, res->ai_family, type,
270 if (connect_timeout > 0) {
271 SIGACTION(SIGALRM, contimeout_handler);
272 alarm(connect_timeout);
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)
292 && establish_proxy_connection(s, host, port,
293 proxy_user, proxy_pass) != 0) {
302 rsyserr(FERROR, errno, "failed to connect to %s", h);
310 * Open an outgoing socket, but allow for it to be intercepted by
311 * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
312 * socketpair rather than really opening a socket.
314 * We use this primarily in testing to detect TCP flow bugs, but not
315 * cause security problems by really opening remote connections.
317 * This is based on the Samba LIBSMB_PROG feature.
319 * @param bind_addr Local address to use. Normally NULL to get the stack default.
321 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
324 char *prog = getenv("RSYNC_CONNECT_PROG");
326 if (prog && strchr(prog, '%')) {
327 int hlen = strlen(host);
328 int len = strlen(prog) + 1;
330 for (f = prog; *f; f++) {
333 /* Compute more than enough room. */
340 if (!(prog = new_array(char, len)))
341 out_of_memory("open_socket_out_wrapped");
342 for (t = prog; *f; f++) {
346 /* Just skips the extra '%'. */
349 memcpy(t, host, hlen);
353 f--; /* pass % through */
363 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
364 prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
368 return sock_exec(prog);
369 return open_socket_out(host, port, bind_addr, af_hint);
375 * Open one or more sockets for incoming data using the specified type,
378 * The getaddrinfo() call may return several address results, e.g. for
379 * the machine's IPv4 and IPv6 name.
381 * We return an array of file-descriptors to the sockets, with a trailing
382 * -1 value to indicate the end of the list.
384 * @param bind_addr Local address to bind, or NULL to allow it to
387 static int *open_socket_in(int type, int port, const char *bind_addr,
391 int s, *socks, maxs, i, ecnt;
392 struct addrinfo hints, *all_ai, *resp;
393 char portbuf[10], **errmsgs;
396 memset(&hints, 0, sizeof hints);
397 hints.ai_family = af_hint;
398 hints.ai_socktype = type;
399 hints.ai_flags = AI_PASSIVE;
400 snprintf(portbuf, sizeof portbuf, "%d", port);
401 error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
403 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
404 bind_addr, gai_strerror(error));
408 /* Count max number of sockets we might open. */
409 for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
411 socks = new_array(int, maxs + 1);
412 errmsgs = new_array(char *, maxs);
413 if (!socks || !errmsgs)
414 out_of_memory("open_socket_in");
416 /* We may not be able to create the socket, if for example the
417 * machine knows about IPv6 in the C library, but not in the
419 for (resp = all_ai, i = ecnt = 0; resp; resp = resp->ai_next) {
420 s = socket(resp->ai_family, resp->ai_socktype,
424 int r = asprintf(&errmsgs[ecnt++],
425 "socket(%d,%d,%d) failed: %s\n",
426 (int)resp->ai_family, (int)resp->ai_socktype,
427 (int)resp->ai_protocol, strerror(errno));
429 out_of_memory("open_socket_in");
430 /* See if there's another address that will work... */
434 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
435 (char *)&one, sizeof one);
438 if (resp->ai_family == AF_INET6) {
439 if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
440 (char *)&one, sizeof one) < 0
441 && default_af_hint != AF_INET6) {
448 /* Now we've got a socket - we need to bind it. */
449 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
450 /* Nope, try another */
451 int r = asprintf(&errmsgs[ecnt++],
452 "bind() failed: %s (address-family %d)\n",
453 strerror(errno), (int)resp->ai_family);
455 out_of_memory("open_socket_in");
465 freeaddrinfo(all_ai);
467 /* Only output the socket()/bind() messages if we were totally
468 * unsuccessful, or if the daemon is being run with -vv. */
469 for (s = 0; s < ecnt; s++) {
470 if (!i || verbose > 1)
471 rwrite(FLOG, errmsgs[s], strlen(errmsgs[s]), 0);
478 "unable to bind any inbound sockets on port %d\n",
488 * Determine if a file descriptor is in fact a socket
490 int is_a_socket(int fd)
493 socklen_t l = sizeof (int);
495 /* Parameters to getsockopt, setsockopt etc are very
496 * unstandardized across platforms, so don't be surprised if
497 * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
498 * It seems they all eventually get the right idea.
500 * Debian says: ``The fifth argument of getsockopt and
501 * setsockopt is in reality an int [*] (and this is what BSD
502 * 4.* and libc4 and libc5 have). Some POSIX confusion
503 * resulted in the present socklen_t. The draft standard has
504 * not been adopted yet, but glibc2 already follows it and
505 * also has socklen_t [*]. See also accept(2).''
507 * We now return to your regularly scheduled programming. */
508 return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
512 static RETSIGTYPE sigchld_handler(UNUSED(int val))
515 while (waitpid(-1, NULL, WNOHANG) > 0) {}
517 #ifndef HAVE_SIGACTION
518 signal(SIGCHLD, sigchld_handler);
523 void start_accept_loop(int port, int (*fn)(int, int))
528 #ifdef HAVE_SIGACTION
529 sigact.sa_flags = SA_NOCLDSTOP;
532 /* open an incoming socket */
533 sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
535 exit_cleanup(RERR_SOCKETIO);
537 /* ready to listen */
539 for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
540 if (listen(sp[i], 5) < 0) {
541 rsyserr(FERROR, errno, "listen() on socket failed");
543 if (errno == EADDRINUSE && i > 0) {
545 "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
548 exit_cleanup(RERR_SOCKETIO);
550 FD_SET(sp[i], &deffds);
555 /* now accept incoming connections - forking a new process
556 * for each incoming connection */
561 struct sockaddr_storage addr;
562 socklen_t addrlen = sizeof addr;
564 /* close log file before the potentially very long select so
565 * file can be trimmed by another process instead of growing
570 FD_COPY(&deffds, &fds);
575 if (select(maxfd + 1, &fds, NULL, NULL, NULL) != 1)
578 for (i = 0, fd = -1; sp[i] >= 0; i++) {
579 if (FD_ISSET(sp[i], &fds)) {
580 fd = accept(sp[i], (struct sockaddr *)&addr,
589 SIGACTION(SIGCHLD, sigchld_handler);
591 if ((pid = fork()) == 0) {
593 for (i = 0; sp[i] >= 0; i++)
595 /* Re-open log file in child before possibly giving
596 * up privileges (see logfile_close() above). */
601 } else if (pid < 0) {
602 rsyserr(FERROR, errno,
603 "could not create child server process");
605 /* This might have happened because we're
606 * overloaded. Sleep briefly before trying to
610 /* Parent doesn't need this fd anymore. */
617 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
626 } socket_options[] = {
627 {"SO_KEEPALIVE", SOL_SOCKET, SO_KEEPALIVE, 0, OPT_BOOL},
628 {"SO_REUSEADDR", SOL_SOCKET, SO_REUSEADDR, 0, OPT_BOOL},
629 {"SO_BROADCAST", SOL_SOCKET, SO_BROADCAST, 0, OPT_BOOL},
631 {"TCP_NODELAY", IPPROTO_TCP, TCP_NODELAY, 0, OPT_BOOL},
633 #ifdef IPTOS_LOWDELAY
634 {"IPTOS_LOWDELAY", IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY, OPT_ON},
636 #ifdef IPTOS_THROUGHPUT
637 {"IPTOS_THROUGHPUT", IPPROTO_IP, IP_TOS, IPTOS_THROUGHPUT, OPT_ON},
640 {"SO_SNDBUF", SOL_SOCKET, SO_SNDBUF, 0, OPT_INT},
643 {"SO_RCVBUF", SOL_SOCKET, SO_RCVBUF, 0, OPT_INT},
646 {"SO_SNDLOWAT", SOL_SOCKET, SO_SNDLOWAT, 0, OPT_INT},
649 {"SO_RCVLOWAT", SOL_SOCKET, SO_RCVLOWAT, 0, OPT_INT},
652 {"SO_SNDTIMEO", SOL_SOCKET, SO_SNDTIMEO, 0, OPT_INT},
655 {"SO_RCVTIMEO", SOL_SOCKET, SO_RCVTIMEO, 0, OPT_INT},
662 * Set user socket options
664 void set_socket_options(int fd, char *options)
668 if (!options || !*options)
671 options = strdup(options);
674 out_of_memory("set_socket_options");
676 for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
682 if ((p = strchr(tok,'='))) {
688 for (i = 0; socket_options[i].name; i++) {
689 if (strcmp(socket_options[i].name,tok)==0)
693 if (!socket_options[i].name) {
694 rprintf(FERROR,"Unknown socket option %s\n",tok);
698 switch (socket_options[i].opttype) {
701 ret = setsockopt(fd,socket_options[i].level,
702 socket_options[i].option,
703 (char *)&value, sizeof (int));
708 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
711 int on = socket_options[i].value;
712 ret = setsockopt(fd,socket_options[i].level,
713 socket_options[i].option,
714 (char *)&on, sizeof (int));
720 rsyserr(FERROR, errno,
721 "failed to set socket option %s", tok);
730 * This is like socketpair but uses tcp. It is used by the Samba
731 * regression test code.
733 * The function guarantees that nobody else can attach to the socket,
734 * or if they do that this function fails and the socket gets closed
735 * returns 0 on success, -1 on failure the resulting file descriptors
738 static int socketpair_tcp(int fd[2])
741 struct sockaddr_in sock;
742 struct sockaddr_in sock2;
743 socklen_t socklen = sizeof sock;
744 int connect_done = 0;
746 fd[0] = fd[1] = listener = -1;
748 memset(&sock, 0, sizeof sock);
750 if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
753 memset(&sock2, 0, sizeof sock2);
754 #ifdef HAVE_SOCKADDR_IN_LEN
755 sock2.sin_len = sizeof sock2;
757 sock2.sin_family = PF_INET;
759 bind(listener, (struct sockaddr *)&sock2, sizeof sock2);
761 if (listen(listener, 1) != 0)
764 if (getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0)
767 if ((fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1)
770 set_nonblocking(fd[1]);
772 sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
774 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) == -1) {
775 if (errno != EINPROGRESS)
780 if ((fd[0] = accept(listener, (struct sockaddr *)&sock, &socklen)) == -1)
788 if (connect_done == 0) {
789 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
810 * Run a program on a local tcp socket, so that we can talk to it's
811 * stdin and stdout. This is used to fake a connection to a daemon
812 * for testing -- not for the normal case of running SSH.
814 * @return a socket which is attached to a subprocess running
815 * "prog". stdin and stdout are attached. stderr is left attached to
816 * the original stderr
818 int sock_exec(const char *prog)
822 if (socketpair_tcp(fd) != 0) {
823 rsyserr(FERROR, errno, "socketpair_tcp failed");
827 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);