2 * network.c -- Provide common network functions for NFS mount/umount
4 * Copyright (C) 2007 Oracle. All rights reserved.
5 * Copyright (C) 2007 Chuck Lever <chuck.lever@oracle.com>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
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 GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public
18 * License along with this program; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 021110-1307, USA.
37 #include <sys/types.h>
38 #include <sys/socket.h>
40 #include <netinet/in.h>
42 #include <rpc/pmap_prot.h>
43 #include <rpc/pmap_clnt.h>
48 #include "nfs_mount.h"
49 #include "mount_constants.h"
54 * Earlier versions of glibc's /usr/include/netdb.h exclude these
55 * definitions because it was thought they were not part of a stable
56 * POSIX standard. However, they are defined by RFC 2553 and 3493
57 * and in POSIX 1003.1-2001, so these definitions were added in later
58 * versions of netdb.h.
61 #define AI_V4MAPPED 0x0008 /* IPv4-mapped addresses are acceptable. */
62 #endif /* AI_V4MAPPED */
64 #define AI_ALL 0x0010 /* Return both IPv4 and IPv6 addresses. */
67 #define AI_ADDRCONFIG 0x0020 /* Use configuration of this host to choose \
68 returned address type. */
69 #endif /* AI_ADDRCONFIG */
71 #define PMAP_TIMEOUT (10)
72 #define CONNECT_TIMEOUT (20)
73 #define MOUNT_TIMEOUT (30)
75 #if SIZEOF_SOCKLEN_T - 0 == 0
76 #define socklen_t unsigned int
79 extern int nfs_mount_data_version;
80 extern char *progname;
83 static const char *nfs_ns_pgmtbl[] = {
88 static const unsigned long nfs_to_mnt[] = {
95 static const unsigned long mnt_to_nfs[] = {
103 * Map an NFS version into the corresponding Mountd version
105 unsigned long nfsvers_to_mnt(const unsigned long vers)
108 return nfs_to_mnt[vers];
113 * Map a Mountd version into the corresponding NFS version
115 static unsigned long mntvers_to_nfs(const unsigned long vers)
118 return mnt_to_nfs[vers];
122 static const unsigned int probe_udp_only[] = {
127 static const unsigned int probe_udp_first[] = {
133 static const unsigned int probe_tcp_first[] = {
139 static const unsigned long probe_nfs2_only[] = {
144 static const unsigned long probe_nfs3_first[] = {
150 static const unsigned long probe_mnt1_first[] = {
156 static const unsigned long probe_mnt3_first[] = {
163 static void nfs_set_port(struct sockaddr *sap, const unsigned short port)
165 switch (sap->sa_family) {
167 ((struct sockaddr_in *)sap)->sin_port = htons(port);
170 ((struct sockaddr_in6 *)sap)->sin6_port = htons(port);
173 nfs_error(_("%s: unrecognized address family in %s"),
179 * nfs_name_to_address - resolve hostname to an IPv4 or IPv6 socket address
180 * @hostname: pointer to C string containing DNS hostname to resolve
181 * @sap: pointer to buffer to fill with socket address
182 * @len: IN: size of buffer to fill; OUT: size of socket address
184 * Returns 1 and places a socket address at @sap if successful;
187 int nfs_name_to_address(const char *hostname,
188 const sa_family_t af_hint,
189 struct sockaddr *sap, socklen_t *salen)
191 struct addrinfo *gai_results;
192 struct addrinfo gai_hint = {
193 .ai_family = af_hint,
194 .ai_flags = AI_ADDRCONFIG,
196 socklen_t len = *salen;
199 if (af_hint == AF_INET6)
200 gai_hint.ai_flags |= AI_V4MAPPED|AI_ALL;
204 error = getaddrinfo(hostname, NULL, &gai_hint, &gai_results);
206 nfs_error(_("%s: DNS resolution failed for %s: %s"),
207 progname, hostname, (error == EAI_SYSTEM ?
208 strerror(errno) : gai_strerror(error)));
212 switch (gai_results->ai_addr->sa_family) {
215 if (len >= gai_results->ai_addrlen) {
216 *salen = gai_results->ai_addrlen;
217 memcpy(sap, gai_results->ai_addr, *salen);
222 /* things are really broken if we get here, so warn */
223 nfs_error(_("%s: unrecognized DNS resolution results for %s"),
228 freeaddrinfo(gai_results);
233 * nfs_gethostbyname - resolve a hostname to an IPv4 address
234 * @hostname: pointer to a C string containing a DNS hostname
235 * @saddr: returns an IPv4 address
237 * Returns 1 if successful, otherwise zero.
239 int nfs_gethostbyname(const char *hostname, struct sockaddr_in *sin)
241 socklen_t len = sizeof(*sin);
243 return nfs_name_to_address(hostname, AF_INET,
244 (struct sockaddr *)sin, &len);
248 * nfs_string_to_sockaddr - convert string address to sockaddr
249 * @address: pointer to presentation format address to convert
250 * @addrlen: length of presentation address
251 * @sap: pointer to socket address buffer to fill in
252 * @salen: IN: length of address buffer
253 * OUT: length of converted socket address
255 * Convert a presentation format address string to a socket address.
256 * Similar to nfs_name_to_address(), but the DNS query is squelched,
257 * and won't make any noise if the getaddrinfo() call fails.
259 * Returns 1 and fills in @sap and @salen if successful; otherwise zero.
261 * See RFC 4038 section 5.1 or RFC 3513 section 2.2 for more details
262 * on presenting IPv6 addresses as text strings.
264 int nfs_string_to_sockaddr(const char *address, const size_t addrlen,
265 struct sockaddr *sap, socklen_t *salen)
267 struct addrinfo *gai_results;
268 struct addrinfo gai_hint = {
269 .ai_flags = AI_NUMERICHOST,
271 socklen_t len = *salen;
276 if (getaddrinfo(address, NULL, &gai_hint, &gai_results) == 0) {
277 switch (gai_results->ai_addr->sa_family) {
280 if (len >= gai_results->ai_addrlen) {
281 *salen = gai_results->ai_addrlen;
282 memcpy(sap, gai_results->ai_addr, *salen);
287 freeaddrinfo(gai_results);
294 * nfs_present_sockaddr - convert sockaddr to string
295 * @sap: pointer to socket address to convert
296 * @salen: length of socket address
297 * @buf: pointer to buffer to fill in
298 * @buflen: length of buffer
300 * Convert the passed-in sockaddr-style address to presentation format.
301 * The presentation format address is placed in @buf and is
304 * Returns 1 if successful; otherwise zero.
306 * See RFC 4038 section 5.1 or RFC 3513 section 2.2 for more details
307 * on presenting IPv6 addresses as text strings.
309 int nfs_present_sockaddr(const struct sockaddr *sap, const socklen_t salen,
310 char *buf, const size_t buflen)
312 #ifdef HAVE_GETNAMEINFO
315 result = getnameinfo(sap, salen, buf, buflen,
316 NULL, 0, NI_NUMERICHOST);
320 nfs_error(_("%s: invalid server address: %s"), progname,
321 gai_strerror(result));
323 #else /* HAVE_GETNAMEINFO */
326 if (sap->sa_family == AF_INET) {
327 addr = inet_ntoa(((struct sockaddr_in *)sap)->sin_addr);
328 if (addr && strlen(addr) < buflen) {
334 nfs_error(_("%s: invalid server address"), progname);
336 #endif /* HAVE_GETNAMEINFO */
340 * Attempt to connect a socket, but time out after "timeout" seconds.
342 * On error return, caller closes the socket.
344 static int connect_to(int fd, struct sockaddr *addr,
345 socklen_t addrlen, int timeout)
349 struct timeval tv = {
353 saved = fcntl(fd, F_GETFL, 0);
354 fcntl(fd, F_SETFL, saved | O_NONBLOCK);
356 ret = connect(fd, addr, addrlen);
357 if (ret < 0 && errno != EINPROGRESS)
365 ret = select(fd + 1, &rset, &wset, NULL, &tv);
370 if (FD_ISSET(fd, &rset) || FD_ISSET(fd, &wset)) {
372 socklen_t len = sizeof(error);
373 if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0)
383 fcntl(fd, F_SETFL, saved);
388 * Create a socket that is locally bound to a reserved or non-reserved port.
390 * The caller should check rpc_createerr to determine the cause of any error.
392 static int get_socket(struct sockaddr_in *saddr, unsigned int p_prot,
393 unsigned int timeout, int resvp, int conn)
396 struct sockaddr_in laddr;
397 socklen_t namelen = sizeof(laddr);
399 type = (p_prot == IPPROTO_UDP ? SOCK_DGRAM : SOCK_STREAM);
400 if ((so = socket (AF_INET, type, p_prot)) < 0)
403 laddr.sin_family = AF_INET;
405 laddr.sin_addr.s_addr = htonl(INADDR_ANY);
407 if (bindresvport(so, &laddr) < 0)
408 goto err_bindresvport;
410 cc = bind(so, (struct sockaddr *)&laddr, namelen);
414 if (type == SOCK_STREAM || (conn && type == SOCK_DGRAM)) {
415 cc = connect_to(so, (struct sockaddr *)saddr, namelen,
423 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
424 rpc_createerr.cf_error.re_errno = errno;
426 nfs_error(_("%s: Unable to create %s socket: errno %d (%s)\n"),
427 progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
428 errno, strerror(errno));
433 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
434 rpc_createerr.cf_error.re_errno = errno;
436 nfs_error(_("%s: Unable to bindresvport %s socket: errno %d"
438 progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
439 errno, strerror(errno));
445 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
446 rpc_createerr.cf_error.re_errno = errno;
448 nfs_error(_("%s: Unable to bind to %s socket: errno %d (%s)\n"),
449 progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
450 errno, strerror(errno));
456 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
457 rpc_createerr.cf_error.re_errno = errno;
459 nfs_error(_("%s: Unable to connect to %s:%d, errno %d (%s)\n"),
460 progname, inet_ntoa(saddr->sin_addr),
461 ntohs(saddr->sin_port), errno, strerror(errno));
467 static void nfs_pp_debug(const struct sockaddr *sap, const socklen_t salen,
468 const rpcprog_t program, const rpcvers_t version,
469 const unsigned short protocol,
470 const unsigned short port)
472 char buf[NI_MAXHOST];
477 if (nfs_present_sockaddr(sap, salen, buf, sizeof(buf)) == 0) {
479 strcat(buf, "unknown host");
482 fprintf(stderr, _("%s: trying %s prog %ld vers %ld prot %s port %d\n"),
483 progname, buf, program, version,
484 (protocol == IPPROTO_UDP ? _("UDP") : _("TCP")),
489 * Use the portmapper to discover whether or not the service we want is
490 * available. The lists 'versions' and 'protos' define ordered sequences
491 * of service versions and udp/tcp protocols to probe for.
493 * Returns 1 if the requested service port is unambiguous and pingable;
494 * @pmap is filled in with the version, port, and transport protocol used
495 * during the successful ping. Note that if a port is already specified
496 * in @pmap and it matches the rpcbind query result, nfs_probe_port() does
497 * not perform an RPC ping.
499 * If an error occurs or the requested service isn't available, zero is
500 * returned; rpccreateerr.cf_stat is set to reflect the nature of the error.
502 static int nfs_probe_port(const struct sockaddr *sap, const socklen_t salen,
503 struct pmap *pmap, const unsigned long *versions,
504 const unsigned int *protos)
506 struct sockaddr_storage address;
507 struct sockaddr *saddr = (struct sockaddr *)&address;
508 const unsigned long prog = pmap->pm_prog, *p_vers;
509 const unsigned int prot = (u_int)pmap->pm_prot, *p_prot;
510 const u_short port = (u_short) pmap->pm_port;
511 unsigned long vers = pmap->pm_vers;
512 unsigned short p_port;
514 memcpy(saddr, sap, salen);
515 p_prot = prot ? &prot : protos;
516 p_vers = vers ? &vers : versions;
517 rpc_createerr.cf_stat = 0;
520 p_port = nfs_getport(saddr, salen, prog, *p_vers, *p_prot);
522 if (!port || port == p_port) {
523 nfs_set_port(saddr, p_port);
524 nfs_pp_debug(saddr, salen, prog, *p_vers,
526 if (nfs_rpc_ping(saddr, salen, prog,
527 *p_vers, *p_prot, NULL))
531 if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED &&
532 rpc_createerr.cf_stat != RPC_TIMEDOUT &&
533 rpc_createerr.cf_stat != RPC_CANTRECV &&
534 rpc_createerr.cf_stat != RPC_PROGVERSMISMATCH)
542 if (rpc_createerr.cf_stat == RPC_TIMEDOUT ||
543 rpc_createerr.cf_stat == RPC_CANTRECV)
546 if (vers || !*++p_vers)
555 pmap->pm_vers = *p_vers;
557 pmap->pm_prot = *p_prot;
559 pmap->pm_port = p_port;
560 rpc_createerr.cf_stat = 0;
565 * Probe a server's NFS service to determine which versions and
566 * transport protocols are supported.
568 * Returns 1 if the requested service port is unambiguous and pingable;
569 * @pmap is filled in with the version, port, and transport protocol used
570 * during the successful ping. If all three are already specified, simply
571 * return success without an rpcbind query or RPC ping (we may be trying
572 * to mount an NFS service that is not advertised via rpcbind).
574 * If an error occurs or the requested service isn't available, zero is
575 * returned; rpccreateerr.cf_stat is set to reflect the nature of the error.
577 static int nfs_probe_nfsport(const struct sockaddr *sap, const socklen_t salen,
580 if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
583 if (nfs_mount_data_version >= 4)
584 return nfs_probe_port(sap, salen, pmap,
585 probe_nfs3_first, probe_tcp_first);
587 return nfs_probe_port(sap, salen, pmap,
588 probe_nfs2_only, probe_udp_only);
592 * Probe a server's mountd service to determine which versions and
593 * transport protocols are supported.
595 * Returns 1 if the requested service port is unambiguous and pingable;
596 * @pmap is filled in with the version, port, and transport protocol used
597 * during the successful ping. If all three are already specified, simply
598 * return success without an rpcbind query or RPC ping (we may be trying
599 * to mount an NFS service that is not advertised via rpcbind).
601 * If an error occurs or the requested service isn't available, zero is
602 * returned; rpccreateerr.cf_stat is set to reflect the nature of the error.
604 static int nfs_probe_mntport(const struct sockaddr *sap, const socklen_t salen,
607 if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
610 if (nfs_mount_data_version >= 4)
611 return nfs_probe_port(sap, salen, pmap,
612 probe_mnt3_first, probe_udp_first);
614 return nfs_probe_port(sap, salen, pmap,
615 probe_mnt1_first, probe_udp_only);
619 * Probe a server's mountd service to determine which versions and
620 * transport protocols are supported. Invoked when the protocol
621 * version is already known for both the NFS and mountd service.
623 * Returns 1 and fills in both @pmap structs if the requested service
624 * ports are unambiguous and pingable. Otherwise zero is returned;
625 * rpccreateerr.cf_stat is set to reflect the nature of the error.
627 static int nfs_probe_version_fixed(const struct sockaddr *mnt_saddr,
628 const socklen_t mnt_salen,
629 struct pmap *mnt_pmap,
630 const struct sockaddr *nfs_saddr,
631 const socklen_t nfs_salen,
632 struct pmap *nfs_pmap)
634 if (!nfs_probe_nfsport(nfs_saddr, nfs_salen, nfs_pmap))
636 return nfs_probe_mntport(mnt_saddr, mnt_salen, mnt_pmap);
640 * nfs_probe_bothports - discover the RPC endpoints of mountd and NFS server
641 * @mnt_saddr: pointer to socket address of mountd server
642 * @mnt_salen: length of mountd server's address
643 * @mnt_pmap: IN: partially filled-in mountd RPC service tuple;
644 * OUT: fully filled-in mountd RPC service tuple
645 * @nfs_saddr: pointer to socket address of NFS server
646 * @nfs_salen: length of NFS server's address
647 * @nfs_pmap: IN: partially filled-in NFS RPC service tuple;
648 * OUT: fully filled-in NFS RPC service tuple
650 * Returns 1 and fills in both @pmap structs if the requested service
651 * ports are unambiguous and pingable. Otherwise zero is returned;
652 * rpccreateerr.cf_stat is set to reflect the nature of the error.
654 int nfs_probe_bothports(const struct sockaddr *mnt_saddr,
655 const socklen_t mnt_salen,
656 struct pmap *mnt_pmap,
657 const struct sockaddr *nfs_saddr,
658 const socklen_t nfs_salen,
659 struct pmap *nfs_pmap)
661 struct pmap save_nfs, save_mnt;
662 const unsigned long *probe_vers;
664 if (mnt_pmap->pm_vers && !nfs_pmap->pm_vers)
665 nfs_pmap->pm_vers = mntvers_to_nfs(mnt_pmap->pm_vers);
666 else if (nfs_pmap->pm_vers && !mnt_pmap->pm_vers)
667 mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
669 if (nfs_pmap->pm_vers)
670 return nfs_probe_version_fixed(mnt_saddr, mnt_salen, mnt_pmap,
671 nfs_saddr, nfs_salen, nfs_pmap);
673 memcpy(&save_nfs, nfs_pmap, sizeof(save_nfs));
674 memcpy(&save_mnt, mnt_pmap, sizeof(save_mnt));
675 probe_vers = (nfs_mount_data_version >= 4) ?
676 probe_mnt3_first : probe_mnt1_first;
678 for (; *probe_vers; probe_vers++) {
679 nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers);
680 if (nfs_probe_nfsport(nfs_saddr, nfs_salen, nfs_pmap) != 0) {
681 mnt_pmap->pm_vers = *probe_vers;
682 if (nfs_probe_mntport(mnt_saddr, mnt_salen, mnt_pmap) != 0)
684 memcpy(mnt_pmap, &save_mnt, sizeof(*mnt_pmap));
686 switch (rpc_createerr.cf_stat) {
687 case RPC_PROGVERSMISMATCH:
688 case RPC_PROGNOTREGISTERED:
693 memcpy(nfs_pmap, &save_nfs, sizeof(*nfs_pmap));
700 * probe_bothports - discover the RPC endpoints of mountd and NFS server
701 * @mnt_server: pointer to address and pmap argument for mountd results
702 * @nfs_server: pointer to address and pmap argument for NFS server
704 * This is the legacy API that takes "clnt_addr_t" for both servers,
705 * but supports only AF_INET addresses.
707 * Returns 1 and fills in the pmap field in both clnt_addr_t structs
708 * if the requested service ports are unambiguous and pingable.
709 * Otherwise zero is returned; rpccreateerr.cf_stat is set to reflect
710 * the nature of the error.
712 int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
714 return nfs_probe_bothports((struct sockaddr *)&mnt_server->saddr,
715 sizeof(mnt_server->saddr),
717 (struct sockaddr *)&nfs_server->saddr,
718 sizeof(nfs_server->saddr),
722 static int nfs_probe_statd(void)
724 struct sockaddr_in addr = {
725 .sin_family = AF_INET,
726 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
728 rpcprog_t program = nfs_getrpcbyname(NSMPROG, nfs_ns_pgmtbl);
730 return nfs_getport_ping((struct sockaddr *)&addr, sizeof(addr),
731 program, (rpcvers_t)1, IPPROTO_UDP);
735 * start_statd - attempt to start rpc.statd
737 * Returns 1 if statd is running; otherwise zero.
739 int start_statd(void)
745 if (nfs_probe_statd())
749 if (stat(START_STATD, &stb) == 0) {
750 if (S_ISREG(stb.st_mode) && (stb.st_mode & S_IXUSR)) {
754 execl(START_STATD, START_STATD, NULL);
757 nfs_error(_("fork failed: %s"),
760 default: /* parent */
761 waitpid(pid, NULL,0);
764 if (nfs_probe_statd())
774 * nfs_call_umount - ask the server to remove a share from it's rmtab
775 * @mnt_server: address of RPC MNT program server
776 * @argp: directory path of share to "unmount"
778 * Returns one if the unmount call succeeded; zero if the unmount
779 * failed for any reason.
781 * Note that a side effect of calling this function is that rpccreateerr
784 int nfs_call_umount(clnt_addr_t *mnt_server, dirpath *argp)
786 struct sockaddr *sap = (struct sockaddr *)&mnt_server->saddr;
787 socklen_t salen = sizeof(mnt_server->saddr);
788 struct pmap *pmap = &mnt_server->pmap;
790 enum clnt_stat res = 0;
793 if (!nfs_probe_mntport(sap, salen, pmap))
795 clnt = mnt_openclnt(mnt_server, &msock);
798 res = clnt_call(clnt, MOUNTPROC_UMNT,
799 (xdrproc_t)xdr_dirpath, (caddr_t)argp,
800 (xdrproc_t)xdr_void, NULL,
802 mnt_closeclnt(clnt, msock);
804 if (res == RPC_SUCCESS)
810 * mnt_openclnt - get a handle for a remote mountd service
811 * @mnt_server: address and pmap arguments of mountd service
812 * @msock: returns a file descriptor of the underlying transport socket
814 * Returns an active handle for the remote's mountd service
816 CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
818 struct sockaddr_in *mnt_saddr = &mnt_server->saddr;
819 struct pmap *mnt_pmap = &mnt_server->pmap;
822 mnt_saddr->sin_port = htons((u_short)mnt_pmap->pm_port);
823 *msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, MOUNT_TIMEOUT,
825 if (*msock == RPC_ANYSOCK) {
826 if (rpc_createerr.cf_error.re_errno == EADDRINUSE)
828 * Probably in-use by a TIME_WAIT connection,
829 * It is worth waiting a while and trying again.
831 rpc_createerr.cf_stat = RPC_TIMEDOUT;
835 switch (mnt_pmap->pm_prot) {
837 clnt = clntudp_bufcreate(mnt_saddr,
838 mnt_pmap->pm_prog, mnt_pmap->pm_vers,
839 RETRY_TIMEOUT, msock,
840 MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
843 clnt = clnttcp_create(mnt_saddr,
844 mnt_pmap->pm_prog, mnt_pmap->pm_vers,
846 MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
850 /* try to mount hostname:dirname */
851 clnt->cl_auth = authunix_create_default();
858 * mnt_closeclnt - terminate a handle for a remote mountd service
859 * @clnt: pointer to an active handle for a remote mountd service
860 * @msock: file descriptor of the underlying transport socket
863 void mnt_closeclnt(CLIENT *clnt, int msock)
865 auth_destroy(clnt->cl_auth);
871 * clnt_ping - send an RPC ping to the remote RPC service endpoint
872 * @saddr: server's address
873 * @prog: target RPC program number
874 * @vers: target RPC version number
875 * @prot: target RPC protocol
876 * @caddr: filled in with our network address
878 * Sigh... GETPORT queries don't actually check the version number.
879 * In order to make sure that the server actually supports the service
880 * we're requesting, we open an RPC client, and fire off a NULL
883 * caddr is the network address that the server will use to call us back.
884 * On multi-homed clients, this address depends on which NIC we use to
885 * route requests to the server.
887 * Returns one if successful, otherwise zero.
889 int clnt_ping(struct sockaddr_in *saddr, const unsigned long prog,
890 const unsigned long vers, const unsigned int prot,
891 struct sockaddr_in *caddr)
895 static char clnt_res;
896 struct sockaddr dissolve;
898 rpc_createerr.cf_stat = stat = 0;
899 sock = get_socket(saddr, prot, CONNECT_TIMEOUT, FALSE, TRUE);
900 if (sock == RPC_ANYSOCK) {
901 if (rpc_createerr.cf_error.re_errno == ETIMEDOUT) {
903 * TCP timeout. Bubble up the error to see
904 * how it should be handled.
906 rpc_createerr.cf_stat = RPC_TIMEDOUT;
912 /* Get the address of our end of this connection */
913 socklen_t len = sizeof(*caddr);
914 if (getsockname(sock, caddr, &len) != 0)
915 caddr->sin_family = 0;
920 /* The socket is connected (so we could getsockname successfully),
921 * but some servers on multi-homed hosts reply from
922 * the wrong address, so if we stay connected, we lose the reply.
924 dissolve.sa_family = AF_UNSPEC;
925 connect(sock, &dissolve, sizeof(dissolve));
927 clnt = clntudp_bufcreate(saddr, prog, vers,
928 RETRY_TIMEOUT, &sock,
929 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
932 clnt = clnttcp_create(saddr, prog, vers, &sock,
933 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
940 memset(&clnt_res, 0, sizeof(clnt_res));
941 stat = clnt_call(clnt, NULLPROC,
942 (xdrproc_t)xdr_void, (caddr_t)NULL,
943 (xdrproc_t)xdr_void, (caddr_t)&clnt_res,
946 clnt_geterr(clnt, &rpc_createerr.cf_error);
947 rpc_createerr.cf_stat = stat;
952 if (stat == RPC_SUCCESS)
959 * Try a getsockname() on a connected datagram socket.
961 * Returns 1 and fills in @buf if successful; otherwise, zero.
963 * A connected datagram socket prevents leaving a socket in TIME_WAIT.
964 * This conserves the ephemeral port number space, helping reduce failed
965 * socket binds during mount storms.
967 static int nfs_ca_sockname(const struct sockaddr *sap, const socklen_t salen,
968 struct sockaddr *buf, socklen_t *buflen)
970 struct sockaddr_in sin = {
971 .sin_family = AF_INET,
972 .sin_addr.s_addr = htonl(INADDR_ANY),
974 struct sockaddr_in6 sin6 = {
975 .sin6_family = AF_INET6,
976 .sin6_addr = IN6ADDR_ANY_INIT,
980 sock = socket(sap->sa_family, SOCK_DGRAM, IPPROTO_UDP);
984 switch (sap->sa_family) {
986 if (bind(sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
992 if (bind(sock, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) {
998 errno = EAFNOSUPPORT;
1002 if (connect(sock, sap, salen) < 0) {
1007 return !getsockname(sock, buf, buflen);
1011 * Try to generate an address that prevents the server from calling us.
1013 * Returns 1 and fills in @buf if successful; otherwise, zero.
1015 static int nfs_ca_gai(const struct sockaddr *sap, const socklen_t salen,
1016 struct sockaddr *buf, socklen_t *buflen)
1018 struct addrinfo *gai_results;
1019 struct addrinfo gai_hint = {
1020 .ai_family = sap->sa_family,
1021 .ai_flags = AI_PASSIVE, /* ANYADDR */
1024 if (getaddrinfo(NULL, "", &gai_hint, &gai_results))
1027 *buflen = gai_results->ai_addrlen;
1028 memcpy(buf, gai_results->ai_addr, *buflen);
1030 freeaddrinfo(gai_results);
1036 * nfs_callback_address - acquire our local network address
1037 * @sap: pointer to address of remote
1038 * @sap_len: length of address
1039 * @buf: pointer to buffer to be filled in with local network address
1040 * @buflen: IN: length of buffer to fill in; OUT: length of filled-in address
1042 * Discover a network address that an NFSv4 server can use to call us back.
1043 * On multi-homed clients, this address depends on which NIC we use to
1044 * route requests to the server.
1046 * Returns 1 and fills in @buf if an unambiguous local address is
1047 * available; returns 1 and fills in an appropriate ANYADDR address
1048 * if a local address isn't available; otherwise, returns zero.
1050 int nfs_callback_address(const struct sockaddr *sap, const socklen_t salen,
1051 struct sockaddr *buf, socklen_t *buflen)
1053 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1055 if (nfs_ca_sockname(sap, salen, buf, buflen) == 0)
1056 if (nfs_ca_gai(sap, salen, buf, buflen) == 0)
1060 * The server can't use an interface ID that was generated
1061 * here on the client, so always clear sin6_scope_id.
1063 if (sin6->sin6_family == AF_INET6)
1064 sin6->sin6_scope_id = 0;
1071 nfs_error(_("%s: failed to construct callback address"));