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;
564 static int probe_nfsport(clnt_addr_t *nfs_server)
566 struct sockaddr *sap = (struct sockaddr *)&nfs_server->saddr;
567 socklen_t salen = sizeof(nfs_server->saddr);
568 struct pmap *pmap = &nfs_server->pmap;
570 if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
573 if (nfs_mount_data_version >= 4)
574 return nfs_probe_port(sap, salen, pmap,
575 probe_nfs3_first, probe_tcp_first);
577 return nfs_probe_port(sap, salen, pmap,
578 probe_nfs2_only, probe_udp_only);
581 static int probe_mntport(clnt_addr_t *mnt_server)
583 struct sockaddr *sap = (struct sockaddr *)&mnt_server->saddr;
584 socklen_t salen = sizeof(mnt_server->saddr);
585 struct pmap *pmap = &mnt_server->pmap;
587 if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
590 if (nfs_mount_data_version >= 4)
591 return nfs_probe_port(sap, salen, pmap,
592 probe_mnt3_first, probe_udp_first);
594 return nfs_probe_port(sap, salen, pmap,
595 probe_mnt1_first, probe_udp_only);
599 * probe_bothports - discover the RPC endpoints of mountd and NFS server
600 * @mnt_server: pointer to address and pmap argument for mountd results
601 * @nfs_server: pointer to address and pmap argument for NFS server
603 * Returns 1 if successful, otherwise zero if some error occurred.
604 * Note that the arguments are both input and output arguments.
606 * A side effect of calling this function is that rpccreateerr is set.
608 int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
610 struct pmap *nfs_pmap = &nfs_server->pmap;
611 struct pmap *mnt_pmap = &mnt_server->pmap;
612 struct pmap save_nfs, save_mnt;
614 const unsigned long *probe_vers;
616 if (mnt_pmap->pm_vers && !nfs_pmap->pm_vers)
617 nfs_pmap->pm_vers = mntvers_to_nfs(mnt_pmap->pm_vers);
618 else if (nfs_pmap->pm_vers && !mnt_pmap->pm_vers)
619 mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
620 if (nfs_pmap->pm_vers)
623 memcpy(&save_nfs, nfs_pmap, sizeof(save_nfs));
624 memcpy(&save_mnt, mnt_pmap, sizeof(save_mnt));
625 probe_vers = (nfs_mount_data_version >= 4) ?
626 probe_mnt3_first : probe_mnt1_first;
628 for (; *probe_vers; probe_vers++) {
629 nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers);
630 if ((res = probe_nfsport(nfs_server) != 0)) {
631 mnt_pmap->pm_vers = *probe_vers;
632 if ((res = probe_mntport(mnt_server)) != 0)
634 memcpy(mnt_pmap, &save_mnt, sizeof(*mnt_pmap));
636 switch (rpc_createerr.cf_stat) {
637 case RPC_PROGVERSMISMATCH:
638 case RPC_PROGNOTREGISTERED:
643 memcpy(nfs_pmap, &save_nfs, sizeof(*nfs_pmap));
650 if (!probe_nfsport(nfs_server))
652 return probe_mntport(mnt_server);
655 static int nfs_probe_statd(void)
657 struct sockaddr_in addr = {
658 .sin_family = AF_INET,
659 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
661 rpcprog_t program = nfs_getrpcbyname(NSMPROG, nfs_ns_pgmtbl);
663 return nfs_getport_ping((struct sockaddr *)&addr, sizeof(addr),
664 program, (rpcvers_t)1, IPPROTO_UDP);
668 * start_statd - attempt to start rpc.statd
670 * Returns 1 if statd is running; otherwise zero.
672 int start_statd(void)
678 if (nfs_probe_statd())
682 if (stat(START_STATD, &stb) == 0) {
683 if (S_ISREG(stb.st_mode) && (stb.st_mode & S_IXUSR)) {
687 execl(START_STATD, START_STATD, NULL);
690 nfs_error(_("fork failed: %s"),
693 default: /* parent */
694 waitpid(pid, NULL,0);
697 if (nfs_probe_statd())
707 * nfs_call_umount - ask the server to remove a share from it's rmtab
708 * @mnt_server: address of RPC MNT program server
709 * @argp: directory path of share to "unmount"
711 * Returns one if the unmount call succeeded; zero if the unmount
712 * failed for any reason.
714 * Note that a side effect of calling this function is that rpccreateerr
717 int nfs_call_umount(clnt_addr_t *mnt_server, dirpath *argp)
720 enum clnt_stat res = 0;
723 if (!probe_mntport(mnt_server))
725 clnt = mnt_openclnt(mnt_server, &msock);
728 res = clnt_call(clnt, MOUNTPROC_UMNT,
729 (xdrproc_t)xdr_dirpath, (caddr_t)argp,
730 (xdrproc_t)xdr_void, NULL,
732 mnt_closeclnt(clnt, msock);
734 if (res == RPC_SUCCESS)
740 * mnt_openclnt - get a handle for a remote mountd service
741 * @mnt_server: address and pmap arguments of mountd service
742 * @msock: returns a file descriptor of the underlying transport socket
744 * Returns an active handle for the remote's mountd service
746 CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
748 struct sockaddr_in *mnt_saddr = &mnt_server->saddr;
749 struct pmap *mnt_pmap = &mnt_server->pmap;
752 mnt_saddr->sin_port = htons((u_short)mnt_pmap->pm_port);
753 *msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, MOUNT_TIMEOUT,
755 if (*msock == RPC_ANYSOCK) {
756 if (rpc_createerr.cf_error.re_errno == EADDRINUSE)
758 * Probably in-use by a TIME_WAIT connection,
759 * It is worth waiting a while and trying again.
761 rpc_createerr.cf_stat = RPC_TIMEDOUT;
765 switch (mnt_pmap->pm_prot) {
767 clnt = clntudp_bufcreate(mnt_saddr,
768 mnt_pmap->pm_prog, mnt_pmap->pm_vers,
769 RETRY_TIMEOUT, msock,
770 MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
773 clnt = clnttcp_create(mnt_saddr,
774 mnt_pmap->pm_prog, mnt_pmap->pm_vers,
776 MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
780 /* try to mount hostname:dirname */
781 clnt->cl_auth = authunix_create_default();
788 * mnt_closeclnt - terminate a handle for a remote mountd service
789 * @clnt: pointer to an active handle for a remote mountd service
790 * @msock: file descriptor of the underlying transport socket
793 void mnt_closeclnt(CLIENT *clnt, int msock)
795 auth_destroy(clnt->cl_auth);
801 * clnt_ping - send an RPC ping to the remote RPC service endpoint
802 * @saddr: server's address
803 * @prog: target RPC program number
804 * @vers: target RPC version number
805 * @prot: target RPC protocol
806 * @caddr: filled in with our network address
808 * Sigh... GETPORT queries don't actually check the version number.
809 * In order to make sure that the server actually supports the service
810 * we're requesting, we open an RPC client, and fire off a NULL
813 * caddr is the network address that the server will use to call us back.
814 * On multi-homed clients, this address depends on which NIC we use to
815 * route requests to the server.
817 * Returns one if successful, otherwise zero.
819 int clnt_ping(struct sockaddr_in *saddr, const unsigned long prog,
820 const unsigned long vers, const unsigned int prot,
821 struct sockaddr_in *caddr)
825 static char clnt_res;
826 struct sockaddr dissolve;
828 rpc_createerr.cf_stat = stat = 0;
829 sock = get_socket(saddr, prot, CONNECT_TIMEOUT, FALSE, TRUE);
830 if (sock == RPC_ANYSOCK) {
831 if (rpc_createerr.cf_error.re_errno == ETIMEDOUT) {
833 * TCP timeout. Bubble up the error to see
834 * how it should be handled.
836 rpc_createerr.cf_stat = RPC_TIMEDOUT;
842 /* Get the address of our end of this connection */
843 socklen_t len = sizeof(*caddr);
844 if (getsockname(sock, caddr, &len) != 0)
845 caddr->sin_family = 0;
850 /* The socket is connected (so we could getsockname successfully),
851 * but some servers on multi-homed hosts reply from
852 * the wrong address, so if we stay connected, we lose the reply.
854 dissolve.sa_family = AF_UNSPEC;
855 connect(sock, &dissolve, sizeof(dissolve));
857 clnt = clntudp_bufcreate(saddr, prog, vers,
858 RETRY_TIMEOUT, &sock,
859 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
862 clnt = clnttcp_create(saddr, prog, vers, &sock,
863 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
870 memset(&clnt_res, 0, sizeof(clnt_res));
871 stat = clnt_call(clnt, NULLPROC,
872 (xdrproc_t)xdr_void, (caddr_t)NULL,
873 (xdrproc_t)xdr_void, (caddr_t)&clnt_res,
876 clnt_geterr(clnt, &rpc_createerr.cf_error);
877 rpc_createerr.cf_stat = stat;
882 if (stat == RPC_SUCCESS)
889 * Try a getsockname() on a connected datagram socket.
891 * Returns 1 and fills in @buf if successful; otherwise, zero.
893 * A connected datagram socket prevents leaving a socket in TIME_WAIT.
894 * This conserves the ephemeral port number space, helping reduce failed
895 * socket binds during mount storms.
897 static int nfs_ca_sockname(const struct sockaddr *sap, const socklen_t salen,
898 struct sockaddr *buf, socklen_t *buflen)
900 struct sockaddr_in sin = {
901 .sin_family = AF_INET,
902 .sin_addr.s_addr = htonl(INADDR_ANY),
904 struct sockaddr_in6 sin6 = {
905 .sin6_family = AF_INET6,
906 .sin6_addr = IN6ADDR_ANY_INIT,
910 sock = socket(sap->sa_family, SOCK_DGRAM, IPPROTO_UDP);
914 switch (sap->sa_family) {
916 if (bind(sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
922 if (bind(sock, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) {
928 errno = EAFNOSUPPORT;
932 if (connect(sock, sap, salen) < 0) {
937 return !getsockname(sock, buf, buflen);
941 * Try to generate an address that prevents the server from calling us.
943 * Returns 1 and fills in @buf if successful; otherwise, zero.
945 static int nfs_ca_gai(const struct sockaddr *sap, const socklen_t salen,
946 struct sockaddr *buf, socklen_t *buflen)
948 struct addrinfo *gai_results;
949 struct addrinfo gai_hint = {
950 .ai_family = sap->sa_family,
951 .ai_flags = AI_PASSIVE, /* ANYADDR */
954 if (getaddrinfo(NULL, "", &gai_hint, &gai_results))
957 *buflen = gai_results->ai_addrlen;
958 memcpy(buf, gai_results->ai_addr, *buflen);
960 freeaddrinfo(gai_results);
966 * nfs_callback_address - acquire our local network address
967 * @sap: pointer to address of remote
968 * @sap_len: length of address
969 * @buf: pointer to buffer to be filled in with local network address
970 * @buflen: IN: length of buffer to fill in; OUT: length of filled-in address
972 * Discover a network address that an NFSv4 server can use to call us back.
973 * On multi-homed clients, this address depends on which NIC we use to
974 * route requests to the server.
976 * Returns 1 and fills in @buf if an unambiguous local address is
977 * available; returns 1 and fills in an appropriate ANYADDR address
978 * if a local address isn't available; otherwise, returns zero.
980 int nfs_callback_address(const struct sockaddr *sap, const socklen_t salen,
981 struct sockaddr *buf, socklen_t *buflen)
983 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
985 if (nfs_ca_sockname(sap, salen, buf, buflen) == 0)
986 if (nfs_ca_gai(sap, salen, buf, buflen) == 0)
990 * The server can't use an interface ID that was generated
991 * here on the client, so always clear sin6_scope_id.
993 if (sin6->sin6_family == AF_INET6)
994 sin6->sin6_scope_id = 0;
1001 nfs_error(_("%s: failed to construct callback address"));