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"
53 * Earlier versions of glibc's /usr/include/netdb.h exclude these
54 * definitions because it was thought they were not part of a stable
55 * POSIX standard. However, they are defined by RFC 2553 and 3493
56 * and in POSIX 1003.1-2001, so these definitions were added in later
57 * versions of netdb.h.
60 #define AI_V4MAPPED 0x0008 /* IPv4-mapped addresses are acceptable. */
61 #endif /* AI_V4MAPPED */
63 #define AI_ALL 0x0010 /* Return both IPv4 and IPv6 addresses. */
66 #define AI_ADDRCONFIG 0x0020 /* Use configuration of this host to choose \
67 returned address type. */
68 #endif /* AI_ADDRCONFIG */
70 #define PMAP_TIMEOUT (10)
71 #define CONNECT_TIMEOUT (20)
72 #define MOUNT_TIMEOUT (30)
74 #if SIZEOF_SOCKLEN_T - 0 == 0
75 #define socklen_t unsigned int
78 extern int nfs_mount_data_version;
79 extern char *progname;
82 static const unsigned long nfs_to_mnt[] = {
89 static const unsigned long mnt_to_nfs[] = {
97 * Map an NFS version into the corresponding Mountd version
99 unsigned long nfsvers_to_mnt(const unsigned long vers)
102 return nfs_to_mnt[vers];
107 * Map a Mountd version into the corresponding NFS version
109 static unsigned long mntvers_to_nfs(const unsigned long vers)
112 return mnt_to_nfs[vers];
116 static const unsigned int probe_udp_only[] = {
121 static const unsigned int probe_udp_first[] = {
127 static const unsigned int probe_tcp_first[] = {
133 static const unsigned long probe_nfs2_only[] = {
138 static const unsigned long probe_nfs3_first[] = {
144 static const unsigned long probe_mnt1_first[] = {
150 static const unsigned long probe_mnt3_first[] = {
158 * nfs_name_to_address - resolve hostname to an IPv4 or IPv6 socket address
159 * @hostname: pointer to C string containing DNS hostname to resolve
160 * @sap: pointer to buffer to fill with socket address
161 * @len: IN: size of buffer to fill; OUT: size of socket address
163 * Returns 1 and places a socket address at @sap if successful;
166 int nfs_name_to_address(const char *hostname,
167 const sa_family_t af_hint,
168 struct sockaddr *sap, socklen_t *salen)
170 struct addrinfo *gai_results;
171 struct addrinfo gai_hint = {
172 .ai_family = af_hint,
173 .ai_flags = AI_ADDRCONFIG,
175 socklen_t len = *salen;
178 if (af_hint == AF_INET6)
179 gai_hint.ai_flags |= AI_V4MAPPED|AI_ALL;
183 error = getaddrinfo(hostname, NULL, &gai_hint, &gai_results);
185 nfs_error(_("%s: DNS resolution failed for %s: %s"),
186 progname, hostname, (error == EAI_SYSTEM ?
187 strerror(errno) : gai_strerror(error)));
191 switch (gai_results->ai_addr->sa_family) {
194 if (len >= gai_results->ai_addrlen) {
195 *salen = gai_results->ai_addrlen;
196 memcpy(sap, gai_results->ai_addr, *salen);
201 /* things are really broken if we get here, so warn */
202 nfs_error(_("%s: unrecognized DNS resolution results for %s"),
207 freeaddrinfo(gai_results);
212 * nfs_gethostbyname - resolve a hostname to an IPv4 address
213 * @hostname: pointer to a C string containing a DNS hostname
214 * @saddr: returns an IPv4 address
216 * Returns 1 if successful, otherwise zero.
218 int nfs_gethostbyname(const char *hostname, struct sockaddr_in *sin)
220 socklen_t len = sizeof(*sin);
222 return nfs_name_to_address(hostname, AF_INET,
223 (struct sockaddr *)sin, &len);
227 * nfs_string_to_sockaddr - convert string address to sockaddr
228 * @address: pointer to presentation format address to convert
229 * @addrlen: length of presentation address
230 * @sap: pointer to socket address buffer to fill in
231 * @salen: IN: length of address buffer
232 * OUT: length of converted socket address
234 * Convert a presentation format address string to a socket address.
235 * Similar to nfs_name_to_address(), but the DNS query is squelched,
236 * and won't make any noise if the getaddrinfo() call fails.
238 * Returns 1 and fills in @sap and @salen if successful; otherwise zero.
240 * See RFC 4038 section 5.1 or RFC 3513 section 2.2 for more details
241 * on presenting IPv6 addresses as text strings.
243 int nfs_string_to_sockaddr(const char *address, const size_t addrlen,
244 struct sockaddr *sap, socklen_t *salen)
246 struct addrinfo *gai_results;
247 struct addrinfo gai_hint = {
248 .ai_flags = AI_NUMERICHOST,
250 socklen_t len = *salen;
255 if (getaddrinfo(address, NULL, &gai_hint, &gai_results) == 0) {
256 switch (gai_results->ai_addr->sa_family) {
259 if (len >= gai_results->ai_addrlen) {
260 *salen = gai_results->ai_addrlen;
261 memcpy(sap, gai_results->ai_addr, *salen);
266 freeaddrinfo(gai_results);
273 * nfs_present_sockaddr - convert sockaddr to string
274 * @sap: pointer to socket address to convert
275 * @salen: length of socket address
276 * @buf: pointer to buffer to fill in
277 * @buflen: length of buffer
279 * Convert the passed-in sockaddr-style address to presentation format.
280 * The presentation format address is placed in @buf and is
283 * Returns 1 if successful; otherwise zero.
285 * See RFC 4038 section 5.1 or RFC 3513 section 2.2 for more details
286 * on presenting IPv6 addresses as text strings.
288 int nfs_present_sockaddr(const struct sockaddr *sap, const socklen_t salen,
289 char *buf, const size_t buflen)
291 #ifdef HAVE_GETNAMEINFO
294 result = getnameinfo(sap, salen, buf, buflen,
295 NULL, 0, NI_NUMERICHOST);
299 nfs_error(_("%s: invalid server address: %s"), progname,
300 gai_strerror(result));
302 #else /* HAVE_GETNAMEINFO */
305 if (sap->sa_family == AF_INET) {
306 addr = inet_ntoa(((struct sockaddr_in *)sap)->sin_addr);
307 if (addr && strlen(addr) < buflen) {
313 nfs_error(_("%s: invalid server address"), progname);
315 #endif /* HAVE_GETNAMEINFO */
319 * Attempt to connect a socket, but time out after "timeout" seconds.
321 * On error return, caller closes the socket.
323 static int connect_to(int fd, struct sockaddr *addr,
324 socklen_t addrlen, int timeout)
328 struct timeval tv = {
332 saved = fcntl(fd, F_GETFL, 0);
333 fcntl(fd, F_SETFL, saved | O_NONBLOCK);
335 ret = connect(fd, addr, addrlen);
336 if (ret < 0 && errno != EINPROGRESS)
344 ret = select(fd + 1, &rset, &wset, NULL, &tv);
349 if (FD_ISSET(fd, &rset) || FD_ISSET(fd, &wset)) {
351 socklen_t len = sizeof(error);
352 if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0)
362 fcntl(fd, F_SETFL, saved);
367 * Create a socket that is locally bound to a reserved or non-reserved port.
369 * The caller should check rpc_createerr to determine the cause of any error.
371 static int get_socket(struct sockaddr_in *saddr, unsigned int p_prot,
372 unsigned int timeout, int resvp, int conn)
375 struct sockaddr_in laddr;
376 socklen_t namelen = sizeof(laddr);
378 type = (p_prot == IPPROTO_UDP ? SOCK_DGRAM : SOCK_STREAM);
379 if ((so = socket (AF_INET, type, p_prot)) < 0)
382 laddr.sin_family = AF_INET;
384 laddr.sin_addr.s_addr = htonl(INADDR_ANY);
386 if (bindresvport(so, &laddr) < 0)
387 goto err_bindresvport;
389 cc = bind(so, (struct sockaddr *)&laddr, namelen);
393 if (type == SOCK_STREAM || (conn && type == SOCK_DGRAM)) {
394 cc = connect_to(so, (struct sockaddr *)saddr, namelen,
402 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
403 rpc_createerr.cf_error.re_errno = errno;
405 nfs_error(_("%s: Unable to create %s socket: errno %d (%s)\n"),
406 progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
407 errno, strerror(errno));
412 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
413 rpc_createerr.cf_error.re_errno = errno;
415 nfs_error(_("%s: Unable to bindresvport %s socket: errno %d"
417 progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
418 errno, strerror(errno));
424 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
425 rpc_createerr.cf_error.re_errno = errno;
427 nfs_error(_("%s: Unable to bind to %s socket: errno %d (%s)\n"),
428 progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
429 errno, strerror(errno));
435 rpc_createerr.cf_stat = RPC_SYSTEMERROR;
436 rpc_createerr.cf_error.re_errno = errno;
438 nfs_error(_("%s: Unable to connect to %s:%d, errno %d (%s)\n"),
439 progname, inet_ntoa(saddr->sin_addr),
440 ntohs(saddr->sin_port), errno, strerror(errno));
447 * getport() is very similar to pmap_getport() with the exception that
448 * this version tries to use an ephemeral port, since reserved ports are
449 * not needed for GETPORT queries. This conserves the very limited
450 * reserved port space, which helps reduce failed socket binds
451 * during mount storms.
453 * A side effect of calling this function is that rpccreateerr is set.
455 static unsigned short getport(struct sockaddr_in *saddr,
456 unsigned long program,
457 unsigned long version,
460 struct sockaddr_in bind_saddr;
461 unsigned short port = 0;
467 bind_saddr.sin_port = htons(PMAPPORT);
469 socket = get_socket(&bind_saddr, proto, PMAP_TIMEOUT, FALSE, TRUE);
470 if (socket == RPC_ANYSOCK) {
471 if (proto == IPPROTO_TCP &&
472 rpc_createerr.cf_error.re_errno == ETIMEDOUT)
473 rpc_createerr.cf_stat = RPC_TIMEDOUT;
479 clnt = clntudp_bufcreate(&bind_saddr,
481 RETRY_TIMEOUT, &socket,
486 clnt = clnttcp_create(&bind_saddr,
489 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
493 struct pmap parms = {
499 stat = clnt_call(clnt, PMAPPROC_GETPORT,
500 (xdrproc_t)xdr_pmap, (caddr_t)&parms,
501 (xdrproc_t)xdr_u_short, (caddr_t)&port,
504 clnt_geterr(clnt, &rpc_createerr.cf_error);
505 rpc_createerr.cf_stat = stat;
508 if (stat != RPC_SUCCESS)
511 rpc_createerr.cf_stat = RPC_PROGNOTREGISTERED;
519 * Use the portmapper to discover whether or not the service we want is
520 * available. The lists 'versions' and 'protos' define ordered sequences
521 * of service versions and udp/tcp protocols to probe for.
523 static int probe_port(clnt_addr_t *server, const unsigned long *versions,
524 const unsigned int *protos)
526 struct sockaddr_in *saddr = &server->saddr;
527 struct pmap *pmap = &server->pmap;
528 const unsigned long prog = pmap->pm_prog, *p_vers;
529 const unsigned int prot = (u_int)pmap->pm_prot, *p_prot;
530 const u_short port = (u_short) pmap->pm_port;
531 unsigned long vers = pmap->pm_vers;
532 unsigned short p_port;
534 p_prot = prot ? &prot : protos;
535 p_vers = vers ? &vers : versions;
536 rpc_createerr.cf_stat = 0;
538 p_port = getport(saddr, prog, *p_vers, *p_prot);
540 if (!port || port == p_port) {
541 saddr->sin_port = htons(p_port);
543 printf(_("%s: trying %s prog %ld vers "
544 "%ld prot %s port %d\n"),
546 inet_ntoa(saddr->sin_addr),
548 *p_prot == IPPROTO_UDP ?
552 if (clnt_ping(saddr, prog, *p_vers, *p_prot, NULL))
556 if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED &&
557 rpc_createerr.cf_stat != RPC_TIMEDOUT &&
558 rpc_createerr.cf_stat != RPC_CANTRECV &&
559 rpc_createerr.cf_stat != RPC_PROGVERSMISMATCH)
567 if (rpc_createerr.cf_stat == RPC_TIMEDOUT ||
568 rpc_createerr.cf_stat == RPC_CANTRECV)
571 if (vers || !*++p_vers)
580 pmap->pm_vers = *p_vers;
582 pmap->pm_prot = *p_prot;
584 pmap->pm_port = p_port;
585 rpc_createerr.cf_stat = 0;
589 static int probe_nfsport(clnt_addr_t *nfs_server)
591 struct pmap *pmap = &nfs_server->pmap;
593 if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
596 if (nfs_mount_data_version >= 4)
597 return probe_port(nfs_server, probe_nfs3_first, probe_tcp_first);
599 return probe_port(nfs_server, probe_nfs2_only, probe_udp_only);
602 static int probe_mntport(clnt_addr_t *mnt_server)
604 struct pmap *pmap = &mnt_server->pmap;
606 if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
609 if (nfs_mount_data_version >= 4)
610 return probe_port(mnt_server, probe_mnt3_first, probe_udp_first);
612 return probe_port(mnt_server, probe_mnt1_first, probe_udp_only);
616 * probe_bothports - discover the RPC endpoints of mountd and NFS server
617 * @mnt_server: pointer to address and pmap argument for mountd results
618 * @nfs_server: pointer to address and pmap argument for NFS server
620 * Returns 1 if successful, otherwise zero if some error occurred.
621 * Note that the arguments are both input and output arguments.
623 * A side effect of calling this function is that rpccreateerr is set.
625 int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
627 struct pmap *nfs_pmap = &nfs_server->pmap;
628 struct pmap *mnt_pmap = &mnt_server->pmap;
629 struct pmap save_nfs, save_mnt;
631 const unsigned long *probe_vers;
633 if (mnt_pmap->pm_vers && !nfs_pmap->pm_vers)
634 nfs_pmap->pm_vers = mntvers_to_nfs(mnt_pmap->pm_vers);
635 else if (nfs_pmap->pm_vers && !mnt_pmap->pm_vers)
636 mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
637 if (nfs_pmap->pm_vers)
640 memcpy(&save_nfs, nfs_pmap, sizeof(save_nfs));
641 memcpy(&save_mnt, mnt_pmap, sizeof(save_mnt));
642 probe_vers = (nfs_mount_data_version >= 4) ?
643 probe_mnt3_first : probe_mnt1_first;
645 for (; *probe_vers; probe_vers++) {
646 nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers);
647 if ((res = probe_nfsport(nfs_server) != 0)) {
648 mnt_pmap->pm_vers = *probe_vers;
649 if ((res = probe_mntport(mnt_server)) != 0)
651 memcpy(mnt_pmap, &save_mnt, sizeof(*mnt_pmap));
653 switch (rpc_createerr.cf_stat) {
654 case RPC_PROGVERSMISMATCH:
655 case RPC_PROGNOTREGISTERED:
660 memcpy(nfs_pmap, &save_nfs, sizeof(*nfs_pmap));
667 if (!probe_nfsport(nfs_server))
669 return probe_mntport(mnt_server);
672 static int probe_statd(void)
674 struct sockaddr_in addr;
677 memset(&addr, 0, sizeof(addr));
678 addr.sin_family = AF_INET;
679 addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
680 port = getport(&addr, 100024, 1, IPPROTO_UDP);
684 addr.sin_port = htons(port);
686 if (clnt_ping(&addr, 100024, 1, IPPROTO_UDP, NULL) <= 0)
693 * start_statd - attempt to start rpc.statd
695 * Returns 1 if statd is running; otherwise zero.
697 int start_statd(void)
707 if (stat(START_STATD, &stb) == 0) {
708 if (S_ISREG(stb.st_mode) && (stb.st_mode & S_IXUSR)) {
712 execl(START_STATD, START_STATD, NULL);
715 perror("Fork failed");
717 default: /* parent */
718 waitpid(pid, NULL,0);
731 * nfs_call_umount - ask the server to remove a share from it's rmtab
732 * @mnt_server: address of RPC MNT program server
733 * @argp: directory path of share to "unmount"
735 * Returns one if the unmount call succeeded; zero if the unmount
736 * failed for any reason.
738 * Note that a side effect of calling this function is that rpccreateerr
741 int nfs_call_umount(clnt_addr_t *mnt_server, dirpath *argp)
744 enum clnt_stat res = 0;
747 if (!probe_mntport(mnt_server))
749 clnt = mnt_openclnt(mnt_server, &msock);
752 res = clnt_call(clnt, MOUNTPROC_UMNT,
753 (xdrproc_t)xdr_dirpath, (caddr_t)argp,
754 (xdrproc_t)xdr_void, NULL,
756 mnt_closeclnt(clnt, msock);
758 if (res == RPC_SUCCESS)
764 * mnt_openclnt - get a handle for a remote mountd service
765 * @mnt_server: address and pmap arguments of mountd service
766 * @msock: returns a file descriptor of the underlying transport socket
768 * Returns an active handle for the remote's mountd service
770 CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
772 struct sockaddr_in *mnt_saddr = &mnt_server->saddr;
773 struct pmap *mnt_pmap = &mnt_server->pmap;
776 mnt_saddr->sin_port = htons((u_short)mnt_pmap->pm_port);
777 *msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, MOUNT_TIMEOUT,
779 if (*msock == RPC_ANYSOCK) {
780 if (rpc_createerr.cf_error.re_errno == EADDRINUSE)
782 * Probably in-use by a TIME_WAIT connection,
783 * It is worth waiting a while and trying again.
785 rpc_createerr.cf_stat = RPC_TIMEDOUT;
789 switch (mnt_pmap->pm_prot) {
791 clnt = clntudp_bufcreate(mnt_saddr,
792 mnt_pmap->pm_prog, mnt_pmap->pm_vers,
793 RETRY_TIMEOUT, msock,
794 MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
797 clnt = clnttcp_create(mnt_saddr,
798 mnt_pmap->pm_prog, mnt_pmap->pm_vers,
800 MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
804 /* try to mount hostname:dirname */
805 clnt->cl_auth = authunix_create_default();
812 * mnt_closeclnt - terminate a handle for a remote mountd service
813 * @clnt: pointer to an active handle for a remote mountd service
814 * @msock: file descriptor of the underlying transport socket
817 void mnt_closeclnt(CLIENT *clnt, int msock)
819 auth_destroy(clnt->cl_auth);
825 * clnt_ping - send an RPC ping to the remote RPC service endpoint
826 * @saddr: server's address
827 * @prog: target RPC program number
828 * @vers: target RPC version number
829 * @prot: target RPC protocol
830 * @caddr: filled in with our network address
832 * Sigh... getport() doesn't actually check the version number.
833 * In order to make sure that the server actually supports the service
834 * we're requesting, we open and RPC client, and fire off a NULL
837 * caddr is the network address that the server will use to call us back.
838 * On multi-homed clients, this address depends on which NIC we use to
839 * route requests to the server.
841 * Returns one if successful, otherwise zero.
843 int clnt_ping(struct sockaddr_in *saddr, const unsigned long prog,
844 const unsigned long vers, const unsigned int prot,
845 struct sockaddr_in *caddr)
849 static char clnt_res;
850 struct sockaddr dissolve;
852 rpc_createerr.cf_stat = stat = 0;
853 sock = get_socket(saddr, prot, CONNECT_TIMEOUT, FALSE, TRUE);
854 if (sock == RPC_ANYSOCK) {
855 if (rpc_createerr.cf_error.re_errno == ETIMEDOUT) {
857 * TCP timeout. Bubble up the error to see
858 * how it should be handled.
860 rpc_createerr.cf_stat = RPC_TIMEDOUT;
866 /* Get the address of our end of this connection */
867 socklen_t len = sizeof(*caddr);
868 if (getsockname(sock, caddr, &len) != 0)
869 caddr->sin_family = 0;
874 /* The socket is connected (so we could getsockname successfully),
875 * but some servers on multi-homed hosts reply from
876 * the wrong address, so if we stay connected, we lose the reply.
878 dissolve.sa_family = AF_UNSPEC;
879 connect(sock, &dissolve, sizeof(dissolve));
881 clnt = clntudp_bufcreate(saddr, prog, vers,
882 RETRY_TIMEOUT, &sock,
883 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
886 clnt = clnttcp_create(saddr, prog, vers, &sock,
887 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
894 memset(&clnt_res, 0, sizeof(clnt_res));
895 stat = clnt_call(clnt, NULLPROC,
896 (xdrproc_t)xdr_void, (caddr_t)NULL,
897 (xdrproc_t)xdr_void, (caddr_t)&clnt_res,
900 clnt_geterr(clnt, &rpc_createerr.cf_error);
901 rpc_createerr.cf_stat = stat;
906 if (stat == RPC_SUCCESS)
913 * Try a getsockname() on a connected datagram socket.
915 * Returns 1 and fills in @buf if successful; otherwise, zero.
917 * A connected datagram socket prevents leaving a socket in TIME_WAIT.
918 * This conserves the ephemeral port number space, helping reduce failed
919 * socket binds during mount storms.
921 static int nfs_ca_sockname(const struct sockaddr *sap, const socklen_t salen,
922 struct sockaddr *buf, socklen_t *buflen)
924 struct sockaddr_in sin = {
925 .sin_family = AF_INET,
926 .sin_addr.s_addr = htonl(INADDR_ANY),
928 struct sockaddr_in6 sin6 = {
929 .sin6_family = AF_INET6,
930 .sin6_addr = IN6ADDR_ANY_INIT,
934 sock = socket(sap->sa_family, SOCK_DGRAM, IPPROTO_UDP);
938 switch (sap->sa_family) {
940 if (bind(sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
946 if (bind(sock, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) {
952 errno = EAFNOSUPPORT;
956 if (connect(sock, sap, salen) < 0) {
961 return !getsockname(sock, buf, buflen);
965 * Try to generate an address that prevents the server from calling us.
967 * Returns 1 and fills in @buf if successful; otherwise, zero.
969 static int nfs_ca_gai(const struct sockaddr *sap, const socklen_t salen,
970 struct sockaddr *buf, socklen_t *buflen)
972 struct addrinfo *gai_results;
973 struct addrinfo gai_hint = {
974 .ai_family = sap->sa_family,
975 .ai_flags = AI_PASSIVE, /* ANYADDR */
978 if (getaddrinfo(NULL, "", &gai_hint, &gai_results))
981 *buflen = gai_results->ai_addrlen;
982 memcpy(buf, gai_results->ai_addr, *buflen);
984 freeaddrinfo(gai_results);
990 * nfs_callback_address - acquire our local network address
991 * @sap: pointer to address of remote
992 * @sap_len: length of address
993 * @buf: pointer to buffer to be filled in with local network address
994 * @buflen: IN: length of buffer to fill in; OUT: length of filled-in address
996 * Discover a network address that an NFSv4 server can use to call us back.
997 * On multi-homed clients, this address depends on which NIC we use to
998 * route requests to the server.
1000 * Returns 1 and fills in @buf if an unambiguous local address is
1001 * available; returns 1 and fills in an appropriate ANYADDR address
1002 * if a local address isn't available; otherwise, returns zero.
1004 int nfs_callback_address(const struct sockaddr *sap, const socklen_t salen,
1005 struct sockaddr *buf, socklen_t *buflen)
1007 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1009 if (nfs_ca_sockname(sap, salen, buf, buflen) == 0)
1010 if (nfs_ca_gai(sap, salen, buf, buflen) == 0)
1014 * The server can't use an interface ID that was generated
1015 * here on the client, so always clear sin6_scope_id.
1017 if (sin6->sin6_family == AF_INET6)
1018 sin6->sin6_scope_id = 0;
1025 nfs_error(_("%s: failed to construct callback address"));