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;
43 * Establish a proxy connection on an open socket to a web proxy by
44 * using the CONNECT method. If proxy_user and proxy_pass are not NULL,
45 * they are used to authenticate to the proxy using the "Basic"
46 * proxy-authorization protocol
48 static int establish_proxy_connection(int fd, char *host, int port,
49 char *proxy_user, char *proxy_pass)
51 char *cp, buffer[1024];
52 char *authhdr, authbuf[1024];
55 if (proxy_user && proxy_pass) {
56 stringjoin(buffer, sizeof buffer,
57 proxy_user, ":", proxy_pass, NULL);
60 if ((len*8 + 5) / 6 >= (int)sizeof authbuf - 3) {
62 "authentication information is too long\n");
66 base64_encode(buffer, len, authbuf, 1);
67 authhdr = "\r\nProxy-Authorization: Basic ";
73 snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",
74 host, port, authhdr, authbuf);
76 if (write(fd, buffer, len) != len) {
77 rsyserr(FERROR, errno, "failed to write to proxy");
81 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
82 if (read(fd, cp, 1) != 1) {
83 rsyserr(FERROR, errno, "failed to read from proxy");
95 if (strncmp(buffer, "HTTP/", 5) != 0) {
96 rprintf(FERROR, "bad response from proxy -- %s\n",
100 for (cp = &buffer[5]; isDigit(cp) || *cp == '.'; cp++) {}
104 rprintf(FERROR, "bad response from proxy -- %s\n",
108 /* throw away the rest of the HTTP header */
110 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
111 if (read(fd, cp, 1) != 1) {
112 rsyserr(FERROR, errno,
113 "failed to read from proxy");
119 if (cp > buffer && *cp == '\n')
121 if (cp == buffer && (*cp == '\n' || *cp == '\r'))
129 * Try to set the local address for a newly-created socket. Return -1
132 int try_bind_local(int s, int ai_family, int ai_socktype,
133 const char *bind_addr)
136 struct addrinfo bhints, *bres_all, *r;
138 memset(&bhints, 0, sizeof bhints);
139 bhints.ai_family = ai_family;
140 bhints.ai_socktype = ai_socktype;
141 bhints.ai_flags = AI_PASSIVE;
142 if ((error = getaddrinfo(bind_addr, NULL, &bhints, &bres_all))) {
143 rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
144 bind_addr, gai_strerror(error));
148 for (r = bres_all; r; r = r->ai_next) {
149 if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
151 freeaddrinfo(bres_all);
155 /* no error message; there might be some problem that allows
156 * creation of the socket but not binding, perhaps if the
157 * machine has no ipv6 address of this name. */
158 freeaddrinfo(bres_all);
162 /* connect() timeout handler based on alarm() */
163 static RETSIGTYPE contimeout_handler(UNUSED(int val))
165 connect_timeout = -1;
169 * Open a socket to a tcp remote host with the specified port .
171 * Based on code from Warren. Proxy support by Stephen Rothwell.
172 * getaddrinfo() rewrite contributed by KAME.net.
174 * Now that we support IPv6 we need to look up the remote machine's
175 * address first, using @p af_hint to set a preference for the type
176 * of address. Then depending on whether it has v4 or v6 addresses we
177 * try to open a connection.
179 * The loop allows for machines with some addresses which may not be
180 * reachable, perhaps because we can't e.g. route ipv6 to that network
181 * but we can get ip4 packets through.
183 * @param bind_addr Local address to use. Normally NULL to bind
184 * the wildcard address.
186 * @param af_hint Address family, e.g. AF_INET or AF_INET6.
188 int open_socket_out(char *host, int port, const char *bind_addr,
191 int type = SOCK_STREAM;
193 struct addrinfo hints, *res0, *res;
198 char *proxy_user = NULL, *proxy_pass = NULL;
200 /* if we have a RSYNC_PROXY env variable then redirect our
201 * connetcion via a web proxy at the given address. */
202 h = getenv("RSYNC_PROXY");
203 proxied = h != NULL && *h != '\0';
206 strlcpy(buffer, h, sizeof buffer);
208 /* Is the USER:PASS@ prefix present? */
209 if ((cp = strrchr(buffer, '@')) != NULL) {
211 /* The remainder is the HOST:PORT part. */
214 if ((cp = strchr(buffer, ':')) == NULL) {
216 "invalid proxy specification: should be USER:PASS@HOST:PORT\n");
224 /* The whole buffer is the HOST:PORT part. */
228 if ((cp = strchr(h, ':')) == NULL) {
230 "invalid proxy specification: should be HOST:PORT\n");
234 strlcpy(portbuf, cp, sizeof portbuf);
235 if (DEBUG_GTE(CONNECT, 1)) {
236 rprintf(FINFO, "connection via http proxy %s port %s\n",
240 snprintf(portbuf, sizeof portbuf, "%d", port);
244 memset(&hints, 0, sizeof hints);
245 hints.ai_family = af_hint;
246 hints.ai_socktype = type;
247 error = getaddrinfo(h, portbuf, &hints, &res0);
249 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
250 h, portbuf, gai_strerror(error));
255 /* Try to connect to all addresses for this machine until we get
256 * through. It might e.g. be multi-homed, or have both IPv4 and IPv6
257 * addresses. We need to create a socket for each record, since the
258 * address record tells us what protocol to use to try to connect. */
259 for (res = res0; res; res = res->ai_next) {
260 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
265 && try_bind_local(s, res->ai_family, type,
271 if (connect_timeout > 0) {
272 SIGACTION(SIGALRM, contimeout_handler);
273 alarm(connect_timeout);
276 set_socket_options(s, sockopts);
277 while (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
278 if (connect_timeout < 0)
279 exit_cleanup(RERR_CONTIMEOUT);
287 if (connect_timeout > 0)
294 && establish_proxy_connection(s, host, port,
295 proxy_user, proxy_pass) != 0) {
304 rsyserr(FERROR, errno, "failed to connect to %s", h);
312 * Open an outgoing socket, but allow for it to be intercepted by
313 * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
314 * socketpair rather than really opening a socket.
316 * We use this primarily in testing to detect TCP flow bugs, but not
317 * cause security problems by really opening remote connections.
319 * This is based on the Samba LIBSMB_PROG feature.
321 * @param bind_addr Local address to use. Normally NULL to get the stack default.
323 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
326 char *prog = getenv("RSYNC_CONNECT_PROG");
328 if (prog && strchr(prog, '%')) {
329 int hlen = strlen(host);
330 int len = strlen(prog) + 1;
332 for (f = prog; *f; f++) {
335 /* Compute more than enough room. */
342 if (!(prog = new_array(char, len)))
343 out_of_memory("open_socket_out_wrapped");
344 for (t = prog; *f; f++) {
348 /* Just skips the extra '%'. */
351 memcpy(t, host, hlen);
355 f--; /* pass % through */
364 if (DEBUG_GTE(CONNECT, 1)) {
365 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
366 prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
370 return sock_exec(prog);
371 return open_socket_out(host, port, bind_addr, af_hint);
377 * Open one or more sockets for incoming data using the specified type,
380 * The getaddrinfo() call may return several address results, e.g. for
381 * the machine's IPv4 and IPv6 name.
383 * We return an array of file-descriptors to the sockets, with a trailing
384 * -1 value to indicate the end of the list.
386 * @param bind_addr Local address to bind, or NULL to allow it to
389 static int *open_socket_in(int type, int port, const char *bind_addr,
393 int s, *socks, maxs, i, ecnt;
394 struct addrinfo hints, *all_ai, *resp;
395 char portbuf[10], **errmsgs;
398 memset(&hints, 0, sizeof hints);
399 hints.ai_family = af_hint;
400 hints.ai_socktype = type;
401 hints.ai_flags = AI_PASSIVE;
402 snprintf(portbuf, sizeof portbuf, "%d", port);
403 error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
405 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
406 bind_addr, gai_strerror(error));
410 /* Count max number of sockets we might open. */
411 for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
413 socks = new_array(int, maxs + 1);
414 errmsgs = new_array(char *, maxs);
415 if (!socks || !errmsgs)
416 out_of_memory("open_socket_in");
418 /* We may not be able to create the socket, if for example the
419 * machine knows about IPv6 in the C library, but not in the
421 for (resp = all_ai, i = ecnt = 0; resp; resp = resp->ai_next) {
422 s = socket(resp->ai_family, resp->ai_socktype,
426 int r = asprintf(&errmsgs[ecnt++],
427 "socket(%d,%d,%d) failed: %s\n",
428 (int)resp->ai_family, (int)resp->ai_socktype,
429 (int)resp->ai_protocol, strerror(errno));
431 out_of_memory("open_socket_in");
432 /* See if there's another address that will work... */
436 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
437 (char *)&one, sizeof one);
439 set_socket_options(s, sockopts);
441 set_socket_options(s, lp_socket_options());
444 if (resp->ai_family == AF_INET6) {
445 if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
446 (char *)&one, sizeof one) < 0
447 && default_af_hint != AF_INET6) {
454 /* Now we've got a socket - we need to bind it. */
455 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
456 /* Nope, try another */
457 int r = asprintf(&errmsgs[ecnt++],
458 "bind() failed: %s (address-family %d)\n",
459 strerror(errno), (int)resp->ai_family);
461 out_of_memory("open_socket_in");
471 freeaddrinfo(all_ai);
473 /* Only output the socket()/bind() messages if we were totally
474 * unsuccessful, or if the daemon is being run with -vv. */
475 for (s = 0; s < ecnt; s++) {
476 if (!i || DEBUG_GTE(BIND, 1))
477 rwrite(FLOG, errmsgs[s], strlen(errmsgs[s]), 0);
484 "unable to bind any inbound sockets on port %d\n",
494 * Determine if a file descriptor is in fact a socket
496 int is_a_socket(int fd)
499 socklen_t l = sizeof (int);
501 /* Parameters to getsockopt, setsockopt etc are very
502 * unstandardized across platforms, so don't be surprised if
503 * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
504 * It seems they all eventually get the right idea.
506 * Debian says: ``The fifth argument of getsockopt and
507 * setsockopt is in reality an int [*] (and this is what BSD
508 * 4.* and libc4 and libc5 have). Some POSIX confusion
509 * resulted in the present socklen_t. The draft standard has
510 * not been adopted yet, but glibc2 already follows it and
511 * also has socklen_t [*]. See also accept(2).''
513 * We now return to your regularly scheduled programming. */
514 return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
518 static RETSIGTYPE sigchld_handler(UNUSED(int val))
521 while (waitpid(-1, NULL, WNOHANG) > 0) {}
523 #ifndef HAVE_SIGACTION
524 signal(SIGCHLD, sigchld_handler);
529 void start_accept_loop(int port, int (*fn)(int, int))
534 #ifdef HAVE_SIGACTION
535 sigact.sa_flags = SA_NOCLDSTOP;
538 /* open an incoming socket */
539 sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
541 exit_cleanup(RERR_SOCKETIO);
543 /* ready to listen */
545 for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
546 if (listen(sp[i], 5) < 0) {
547 rsyserr(FERROR, errno, "listen() on socket failed");
549 if (errno == EADDRINUSE && i > 0) {
551 "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
554 exit_cleanup(RERR_SOCKETIO);
556 FD_SET(sp[i], &deffds);
561 /* now accept incoming connections - forking a new process
562 * for each incoming connection */
567 struct sockaddr_storage addr;
568 socklen_t addrlen = sizeof addr;
570 /* close log file before the potentially very long select so
571 * file can be trimmed by another process instead of growing
576 FD_COPY(&deffds, &fds);
581 if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 1)
584 for (i = 0, fd = -1; sp[i] >= 0; i++) {
585 if (FD_ISSET(sp[i], &fds)) {
586 fd = accept(sp[i], (struct sockaddr *)&addr,
595 SIGACTION(SIGCHLD, sigchld_handler);
597 if ((pid = fork()) == 0) {
599 for (i = 0; sp[i] >= 0; i++)
601 /* Re-open log file in child before possibly giving
602 * up privileges (see logfile_close() above). */
607 } else if (pid < 0) {
608 rsyserr(FERROR, errno,
609 "could not create child server process");
611 /* This might have happened because we're
612 * overloaded. Sleep briefly before trying to
616 /* Parent doesn't need this fd anymore. */
623 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
632 } socket_options[] = {
633 {"SO_KEEPALIVE", SOL_SOCKET, SO_KEEPALIVE, 0, OPT_BOOL},
634 {"SO_REUSEADDR", SOL_SOCKET, SO_REUSEADDR, 0, OPT_BOOL},
635 {"SO_BROADCAST", SOL_SOCKET, SO_BROADCAST, 0, OPT_BOOL},
637 {"TCP_NODELAY", IPPROTO_TCP, TCP_NODELAY, 0, OPT_BOOL},
639 #ifdef IPTOS_LOWDELAY
640 {"IPTOS_LOWDELAY", IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY, OPT_ON},
642 #ifdef IPTOS_THROUGHPUT
643 {"IPTOS_THROUGHPUT", IPPROTO_IP, IP_TOS, IPTOS_THROUGHPUT, OPT_ON},
646 {"SO_SNDBUF", SOL_SOCKET, SO_SNDBUF, 0, OPT_INT},
649 {"SO_RCVBUF", SOL_SOCKET, SO_RCVBUF, 0, OPT_INT},
652 {"SO_SNDLOWAT", SOL_SOCKET, SO_SNDLOWAT, 0, OPT_INT},
655 {"SO_RCVLOWAT", SOL_SOCKET, SO_RCVLOWAT, 0, OPT_INT},
658 {"SO_SNDTIMEO", SOL_SOCKET, SO_SNDTIMEO, 0, OPT_INT},
661 {"SO_RCVTIMEO", SOL_SOCKET, SO_RCVTIMEO, 0, OPT_INT},
668 * Set user socket options
670 void set_socket_options(int fd, char *options)
674 if (!options || !*options)
677 options = strdup(options);
680 out_of_memory("set_socket_options");
682 for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
688 if ((p = strchr(tok,'='))) {
694 for (i = 0; socket_options[i].name; i++) {
695 if (strcmp(socket_options[i].name,tok)==0)
699 if (!socket_options[i].name) {
700 rprintf(FERROR,"Unknown socket option %s\n",tok);
704 switch (socket_options[i].opttype) {
707 ret = setsockopt(fd,socket_options[i].level,
708 socket_options[i].option,
709 (char *)&value, sizeof (int));
714 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
717 int on = socket_options[i].value;
718 ret = setsockopt(fd,socket_options[i].level,
719 socket_options[i].option,
720 (char *)&on, sizeof (int));
726 rsyserr(FERROR, errno,
727 "failed to set socket option %s", tok);
736 * This is like socketpair but uses tcp. It is used by the Samba
737 * regression test code.
739 * The function guarantees that nobody else can attach to the socket,
740 * or if they do that this function fails and the socket gets closed
741 * returns 0 on success, -1 on failure the resulting file descriptors
744 static int socketpair_tcp(int fd[2])
747 struct sockaddr_in sock;
748 struct sockaddr_in sock2;
749 socklen_t socklen = sizeof sock;
750 int connect_done = 0;
752 fd[0] = fd[1] = listener = -1;
754 memset(&sock, 0, sizeof sock);
756 if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
759 memset(&sock2, 0, sizeof sock2);
760 #ifdef HAVE_SOCKADDR_IN_LEN
761 sock2.sin_len = sizeof sock2;
763 sock2.sin_family = PF_INET;
765 bind(listener, (struct sockaddr *)&sock2, sizeof sock2);
767 if (listen(listener, 1) != 0)
770 if (getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0)
773 if ((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 *)&sock, &socklen)) == -1)
794 if (connect_done == 0) {
795 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
816 * Run a program on a local tcp socket, so that we can talk to it's
817 * stdin and stdout. This is used to fake a connection to a daemon
818 * for testing -- not for the normal case of running SSH.
820 * @return a socket which is attached to a subprocess running
821 * "prog". stdin and stdout are attached. stderr is left attached to
822 * the original stderr
824 int sock_exec(const char *prog)
829 if (socketpair_tcp(fd) != 0) {
830 rsyserr(FERROR, errno, "socketpair_tcp failed");
833 if (DEBUG_GTE(CMD, 1))
834 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);
838 rsyserr(FERROR, errno, "fork");
839 exit_cleanup(RERR_IPC);
844 if (dup2(fd[1], STDIN_FILENO) < 0
845 || dup2(fd[1], STDOUT_FILENO) < 0) {
846 fprintf(stderr, "Failed to run \"%s\"\n", prog);