X-Git-Url: https://git.decadent.org.uk/gitweb/?p=nfs-utils.git;a=blobdiff_plain;f=utils%2Fmount%2Fnetwork.c;h=849ce1d6825da3ad0d8865b28876a54d5713a91f;hp=ab8cfb751a021989721074486f8c87791415e280;hb=6ab9cdacd2ea314a837c7affb840aeeec620cb66;hpb=a574c7558e33f172b6dfee53ee8df9e59c84c7b5

diff --git a/utils/mount/network.c b/utils/mount/network.c
index ab8cfb7..849ce1d 100644
--- a/utils/mount/network.c
+++ b/utils/mount/network.c
@@ -21,6 +21,10 @@
  *
  */
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 #include <ctype.h>
 #include <unistd.h>
 #include <stdio.h>
@@ -29,16 +33,17 @@
 #include <errno.h>
 #include <netdb.h>
 #include <time.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
 #include <rpc/rpc.h>
 #include <rpc/pmap_prot.h>
 #include <rpc/pmap_clnt.h>
-#include <sys/socket.h>
 
-#include "conn.h"
 #include "xcommon.h"
 #include "mount.h"
 #include "nls.h"
-#include "nfsumount.h"
 #include "nfs_mount.h"
 #include "mount_constants.h"
 #include "network.h"
@@ -54,10 +59,52 @@
 #define NFS_PORT 2049
 #endif
 
+#define PMAP_TIMEOUT	(10)
+#define CONNECT_TIMEOUT	(20)
+#define MOUNT_TIMEOUT	(30)
+
+#if SIZEOF_SOCKLEN_T - 0 == 0
+#define socklen_t unsigned int
+#endif
+
 extern int nfs_mount_data_version;
 extern char *progname;
 extern int verbose;
 
+static const unsigned long nfs_to_mnt[] = {
+	0,
+	0,
+	1,
+	3,
+};
+
+static const unsigned long mnt_to_nfs[] = {
+	0,
+	2,
+	2,
+	3,
+};
+
+/*
+ * Map an NFS version into the corresponding Mountd version
+ */
+unsigned long nfsvers_to_mnt(const unsigned long vers)
+{
+	if (vers <= 3)
+		return nfs_to_mnt[vers];
+	return 0;
+}
+
+/*
+ * Map a Mountd version into the corresponding NFS version
+ */
+static unsigned long mntvers_to_nfs(const unsigned long vers)
+{
+	if (vers <= 3)
+		return mnt_to_nfs[vers];
+	return 0;
+}
+
 static const unsigned int probe_udp_only[] = {
 	IPPROTO_UDP,
 	0,
@@ -99,65 +146,352 @@ static const unsigned long probe_mnt3_first[] = {
 	0,
 };
 
-int nfs_gethostbyname(const char *hostname, struct sockaddr_in *saddr)
+/**
+ * nfs_name_to_address - resolve hostname to an IPv4 or IPv6 socket address
+ * @hostname: pointer to C string containing DNS hostname to resolve
+ * @sap: pointer to buffer to fill with socket address
+ * @len: IN: size of buffer to fill; OUT: size of socket address
+ *
+ * Returns 1 and places a socket address at @sap if successful;
+ * otherwise zero.
+ */
+int nfs_name_to_address(const char *hostname,
+			const sa_family_t af_hint,
+			struct sockaddr *sap, socklen_t *salen)
 {
-	struct hostent *hp;
+	struct addrinfo *gai_results;
+	struct addrinfo gai_hint = {
+		.ai_family	= af_hint,
+		.ai_flags	= AI_ADDRCONFIG,
+	};
+	socklen_t len = *salen;
+	int error, ret = 0;
 
-	saddr->sin_family = AF_INET;
-	if (!inet_aton(hostname, &saddr->sin_addr)) {
-		if ((hp = gethostbyname(hostname)) == NULL) {
-			nfs_error(_("%s: can't get address for %s\n"),
-					progname, hostname);
-			return 0;
-		} else {
-			if (hp->h_length > sizeof(*saddr)) {
-				nfs_error(_("%s: got bad hp->h_length\n"),
-						progname);
-				hp->h_length = sizeof(*saddr);
+	if (af_hint == AF_INET6)
+		gai_hint.ai_flags |= AI_V4MAPPED|AI_ALL;
+
+	*salen = 0;
+
+	error = getaddrinfo(hostname, NULL, &gai_hint, &gai_results);
+	if (error) {
+		nfs_error(_("%s: DNS resolution failed for %s: %s"),
+			progname, hostname, (error == EAI_SYSTEM ?
+				strerror(errno) : gai_strerror(error)));
+		return ret;
+	}
+
+	switch (gai_results->ai_addr->sa_family) {
+	case AF_INET:
+	case AF_INET6:
+		if (len >= gai_results->ai_addrlen) {
+			*salen = gai_results->ai_addrlen;
+			memcpy(sap, gai_results->ai_addr, *salen);
+			ret = 1;
+		}
+		break;
+	default:
+		/* things are really broken if we get here, so warn */
+		nfs_error(_("%s: unrecognized DNS resolution results for %s"),
+				progname, hostname);
+		break;
+	}
+
+	freeaddrinfo(gai_results);
+	return ret;
+}
+
+/**
+ * nfs_gethostbyname - resolve a hostname to an IPv4 address
+ * @hostname: pointer to a C string containing a DNS hostname
+ * @saddr: returns an IPv4 address 
+ *
+ * Returns 1 if successful, otherwise zero.
+ */
+int nfs_gethostbyname(const char *hostname, struct sockaddr_in *sin)
+{
+	socklen_t len = sizeof(*sin);
+
+	return nfs_name_to_address(hostname, AF_INET,
+					(struct sockaddr *)sin, &len);
+}
+
+/**
+ * nfs_string_to_sockaddr - convert string address to sockaddr
+ * @address:	pointer to presentation format address to convert
+ * @addrlen:	length of presentation address
+ * @sap:	pointer to socket address buffer to fill in
+ * @salen:	IN: length of address buffer
+ *		OUT: length of converted socket address
+ *
+ * Convert a presentation format address string to a socket address.
+ * Similar to nfs_name_to_address(), but the DNS query is squelched,
+ * and won't make any noise if the getaddrinfo() call fails.
+ *
+ * Returns 1 and fills in @sap and @salen if successful; otherwise zero.
+ *
+ * See RFC 4038 section 5.1 or RFC 3513 section 2.2 for more details
+ * on presenting IPv6 addresses as text strings.
+ */
+int nfs_string_to_sockaddr(const char *address, const size_t addrlen,
+			   struct sockaddr *sap, socklen_t *salen)
+{
+	struct addrinfo *gai_results;
+	struct addrinfo gai_hint = {
+		.ai_flags	= AI_NUMERICHOST,
+	};
+	socklen_t len = *salen;
+	int ret = 0;
+
+	*salen = 0;
+
+	if (getaddrinfo(address, NULL, &gai_hint, &gai_results) == 0) {
+		switch (gai_results->ai_addr->sa_family) {
+		case AF_INET:
+		case AF_INET6:
+			if (len >= gai_results->ai_addrlen) {
+				*salen = gai_results->ai_addrlen;
+				memcpy(sap, gai_results->ai_addr, *salen);
+				ret = 1;
 			}
-			memcpy(&saddr->sin_addr, hp->h_addr, hp->h_length);
+			break;
 		}
+		freeaddrinfo(gai_results);
 	}
-	return 1;
+
+	return ret;
+}
+
+/**
+ * nfs_present_sockaddr - convert sockaddr to string
+ * @sap: pointer to socket address to convert
+ * @salen: length of socket address
+ * @buf: pointer to buffer to fill in
+ * @buflen: length of buffer
+ *
+ * Convert the passed-in sockaddr-style address to presentation format.
+ * The presentation format address is placed in @buf and is
+ * '\0'-terminated.
+ *
+ * Returns 1 if successful; otherwise zero.
+ *
+ * See RFC 4038 section 5.1 or RFC 3513 section 2.2 for more details
+ * on presenting IPv6 addresses as text strings.
+ */
+int nfs_present_sockaddr(const struct sockaddr *sap, const socklen_t salen,
+			 char *buf, const size_t buflen)
+{
+#ifdef HAVE_GETNAMEINFO
+	int result;
+
+	result = getnameinfo(sap, salen, buf, buflen,
+					NULL, 0, NI_NUMERICHOST);
+	if (!result)
+		return 1;
+
+	nfs_error(_("%s: invalid server address: %s"), progname,
+			gai_strerror(result));
+	return 0;
+#else	/* HAVE_GETNAMEINFO */
+	char *addr;
+
+	if (sap->sa_family == AF_INET) {
+		addr = inet_ntoa(((struct sockaddr_in *)sap)->sin_addr);
+		if (addr && strlen(addr) < buflen) {
+			strcpy(buf, addr);
+			return 1;
+		}
+	}
+
+	nfs_error(_("%s: invalid server address"), progname);
+	return 0;
+#endif	/* HAVE_GETNAMEINFO */
+}
+
+/*
+ * Attempt to connect a socket, but time out after "timeout" seconds.
+ *
+ * On error return, caller closes the socket.
+ */
+static int connect_to(int fd, struct sockaddr *addr,
+			socklen_t addrlen, int timeout)
+{
+	int ret, saved;
+	fd_set rset, wset;
+	struct timeval tv = {
+		.tv_sec = timeout,
+	};
+
+	saved = fcntl(fd, F_GETFL, 0);
+	fcntl(fd, F_SETFL, saved | O_NONBLOCK);
+
+	ret = connect(fd, addr, addrlen);
+	if (ret < 0 && errno != EINPROGRESS)
+		return -1;
+	if (ret == 0)
+		goto out;
+
+	FD_ZERO(&rset);
+	FD_SET(fd, &rset);
+	wset = rset;
+	ret = select(fd + 1, &rset, &wset, NULL, &tv);
+	if (ret == 0) {
+		errno = ETIMEDOUT;
+		return -1;
+	}
+	if (FD_ISSET(fd, &rset) || FD_ISSET(fd, &wset)) {
+		int error;
+		socklen_t len = sizeof(error);
+		if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0)
+			return -1;
+		if (error) {
+			errno = error;
+			return -1;
+		}
+	} else
+		return -1;
+
+out:
+	fcntl(fd, F_SETFL, saved);
+	return 0;
+}
+
+/*
+ * Create a socket that is locally bound to a reserved or non-reserved port.
+ *
+ * The caller should check rpc_createerr to determine the cause of any error.
+ */
+static int get_socket(struct sockaddr_in *saddr, unsigned int p_prot,
+			unsigned int timeout, int resvp, int conn)
+{
+	int so, cc, type;
+	struct sockaddr_in laddr;
+	socklen_t namelen = sizeof(laddr);
+
+	type = (p_prot == IPPROTO_UDP ? SOCK_DGRAM : SOCK_STREAM);
+	if ((so = socket (AF_INET, type, p_prot)) < 0)
+		goto err_socket;
+
+	laddr.sin_family = AF_INET;
+	laddr.sin_port = 0;
+	laddr.sin_addr.s_addr = htonl(INADDR_ANY);
+	if (resvp) {
+		if (bindresvport(so, &laddr) < 0)
+			goto err_bindresvport;
+	} else {
+		cc = bind(so, (struct sockaddr *)&laddr, namelen);
+		if (cc < 0)
+			goto err_bind;
+	}
+	if (type == SOCK_STREAM || (conn && type == SOCK_DGRAM)) {
+		cc = connect_to(so, (struct sockaddr *)saddr, namelen,
+				timeout);
+		if (cc < 0)
+			goto err_connect;
+	}
+	return so;
+
+err_socket:
+	rpc_createerr.cf_stat = RPC_SYSTEMERROR;
+	rpc_createerr.cf_error.re_errno = errno;
+	if (verbose) {
+		nfs_error(_("%s: Unable to create %s socket: errno %d (%s)\n"),
+			progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
+			errno, strerror(errno));
+	}
+	return RPC_ANYSOCK;
+
+err_bindresvport:
+	rpc_createerr.cf_stat = RPC_SYSTEMERROR;
+	rpc_createerr.cf_error.re_errno = errno;
+	if (verbose) {
+		nfs_error(_("%s: Unable to bindresvport %s socket: errno %d"
+				" (%s)\n"),
+			progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
+			errno, strerror(errno));
+	}
+	close(so);
+	return RPC_ANYSOCK;
+
+err_bind:
+	rpc_createerr.cf_stat = RPC_SYSTEMERROR;
+	rpc_createerr.cf_error.re_errno = errno;
+	if (verbose) {
+		nfs_error(_("%s: Unable to bind to %s socket: errno %d (%s)\n"),
+			progname, p_prot == IPPROTO_UDP ? _("UDP") : _("TCP"),
+			errno, strerror(errno));
+	}
+	close(so);
+	return RPC_ANYSOCK;
+
+err_connect:
+	rpc_createerr.cf_stat = RPC_SYSTEMERROR;
+	rpc_createerr.cf_error.re_errno = errno;
+	if (verbose) {
+		nfs_error(_("%s: Unable to connect to %s:%d, errno %d (%s)\n"),
+			progname, inet_ntoa(saddr->sin_addr),
+			ntohs(saddr->sin_port), errno, strerror(errno));
+	}
+	close(so);
+	return RPC_ANYSOCK;
 }
 
 /*
- * getport() is very similar to pmap_getport() with
- * the exception this version uses a non-reserve ports
- * instead of reserve ports since reserve ports
- * are not needed for pmap requests.
+ * getport() is very similar to pmap_getport() with the exception that
+ * this version tries to use an ephemeral port, since reserved ports are
+ * not needed for GETPORT queries.  This conserves the very limited
+ * reserved port space, which helps reduce failed socket binds
+ * during mount storms.
+ *
+ * A side effect of calling this function is that rpccreateerr is set.
  */
-unsigned short getport(struct sockaddr_in *saddr, unsigned long prog,
-			unsigned long vers, unsigned int prot)
+static unsigned short getport(struct sockaddr_in *saddr,
+				unsigned long program,
+				unsigned long version,
+				unsigned int proto)
 {
+	struct sockaddr_in bind_saddr;
 	unsigned short port = 0;
 	int socket;
 	CLIENT *clnt = NULL;
-	struct pmap parms;
 	enum clnt_stat stat;
+ 
+	bind_saddr = *saddr;
+	bind_saddr.sin_port = htons(PMAPPORT);
 
-	saddr->sin_port = htons (PMAPPORT);
-	socket = get_socket(saddr, prot, FALSE, FALSE);
+	socket = get_socket(&bind_saddr, proto, PMAP_TIMEOUT, FALSE, FALSE);
+	if (socket == RPC_ANYSOCK) {
+		if (proto == IPPROTO_TCP &&
+		    rpc_createerr.cf_error.re_errno == ETIMEDOUT)
+			rpc_createerr.cf_stat = RPC_TIMEDOUT;
+		return 0;
+	}
 
-	switch (prot) {
+	switch (proto) {
 	case IPPROTO_UDP:
-		clnt = clntudp_bufcreate(saddr,
-					 PMAPPROG, PMAPVERS, TIMEOUT, &socket,
-					 UDPMSGSIZE, UDPMSGSIZE);
+		clnt = clntudp_bufcreate(&bind_saddr,
+					 PMAPPROG, PMAPVERS,
+					 RETRY_TIMEOUT, &socket,
+					 RPCSMALLMSGSIZE,
+					 RPCSMALLMSGSIZE);
 		break;
 	case IPPROTO_TCP:
-		clnt = clnttcp_create(saddr,
-			PMAPPROG, PMAPVERS, &socket, 50, 500);
+		clnt = clnttcp_create(&bind_saddr,
+				      PMAPPROG, PMAPVERS,
+				      &socket,
+				      RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
 		break;
 	}
 	if (clnt != NULL) {
-		parms.pm_prog = prog;
-		parms.pm_vers = vers;
-		parms.pm_prot = prot;
-		parms.pm_port = 0;    /* not needed or used */
+		struct pmap parms = {
+			.pm_prog	= program,
+			.pm_vers	= version,
+			.pm_prot	= proto,
+		};
 
-		stat = clnt_call(clnt, PMAPPROC_GETPORT, (xdrproc_t)xdr_pmap,
-			(caddr_t)&parms, (xdrproc_t)xdr_u_short, (caddr_t)&port, TIMEOUT);
+		stat = clnt_call(clnt, PMAPPROC_GETPORT,
+				 (xdrproc_t)xdr_pmap, (caddr_t)&parms,
+				 (xdrproc_t)xdr_u_short, (caddr_t)&port,
+				 TIMEOUT);
 		if (stat) {
 			clnt_geterr(clnt, &rpc_createerr.cf_error);
 			rpc_createerr.cf_stat = stat;
@@ -168,8 +502,7 @@ unsigned short getport(struct sockaddr_in *saddr, unsigned long prog,
 		else if (port == 0)
 			rpc_createerr.cf_stat = RPC_PROGNOTREGISTERED;
 	}
-	if (socket != 1)
-		close(socket);
+	close(socket);
 
 	return port;
 }
@@ -194,7 +527,6 @@ static int probe_port(clnt_addr_t *server, const unsigned long *versions,
 	p_vers = vers ? &vers : versions;
 	rpc_createerr.cf_stat = 0;
 	for (;;) {
-		saddr->sin_port = htons(PMAPPORT);
 		p_port = getport(saddr, prog, *p_vers, *p_prot);
 		if (p_port) {
 			if (!port || port == p_port) {
@@ -206,7 +538,7 @@ static int probe_port(clnt_addr_t *server, const unsigned long *versions,
 						inet_ntoa(saddr->sin_addr),
 						prog, *p_vers,
 						*p_prot == IPPROTO_UDP ?
-							"udp" : "tcp",
+							_("UDP") : _("TCP"),
 						p_port);
                                 }
 				if (clnt_ping(saddr, prog, *p_vers, *p_prot, NULL))
@@ -215,7 +547,8 @@ static int probe_port(clnt_addr_t *server, const unsigned long *versions,
 					goto out_bad;
 			}
 		}
-		if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED)
+		if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED &&
+		    rpc_createerr.cf_stat != RPC_PROGVERSMISMATCH)
 			goto out_bad;
 
 		if (!prot) {
@@ -223,10 +556,6 @@ static int probe_port(clnt_addr_t *server, const unsigned long *versions,
 				continue;
 			p_prot = protos;
 		}
-		if (vers == pmap->pm_vers) {
-			p_vers = versions;
-			vers = 0;
-		}
 		if (vers || !*++p_vers)
 			break;
 	}
@@ -245,7 +574,7 @@ out_ok:
 	return 1;
 }
 
-int probe_nfsport(clnt_addr_t *nfs_server)
+static int probe_nfsport(clnt_addr_t *nfs_server)
 {
 	struct pmap *pmap = &nfs_server->pmap;
 
@@ -258,7 +587,7 @@ int probe_nfsport(clnt_addr_t *nfs_server)
 		return probe_port(nfs_server, probe_nfs2_only, probe_udp_only);
 }
 
-int probe_mntport(clnt_addr_t *mnt_server)
+static int probe_mntport(clnt_addr_t *mnt_server)
 {
 	struct pmap *pmap = &mnt_server->pmap;
 
@@ -271,6 +600,16 @@ int probe_mntport(clnt_addr_t *mnt_server)
 		return probe_port(mnt_server, probe_mnt1_first, probe_udp_only);
 }
 
+/**
+ * probe_bothports - discover the RPC endpoints of mountd and NFS server
+ * @mnt_server: pointer to address and pmap argument for mountd results
+ * @nfs_server: pointer to address and pmap argument for NFS server
+ *
+ * Returns 1 if successful, otherwise zero if some error occurred.
+ * Note that the arguments are both input and output arguments.
+ *
+ * A side effect of calling this function is that rpccreateerr is set.
+ */
 int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
 {
 	struct pmap *nfs_pmap = &nfs_server->pmap;
@@ -294,7 +633,7 @@ int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
 	for (; *probe_vers; probe_vers++) {
 		nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers);
 		if ((res = probe_nfsport(nfs_server) != 0)) {
-			mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
+			mnt_pmap->pm_vers = *probe_vers;
 			if ((res = probe_mntport(mnt_server)) != 0)
 				return 1;
 			memcpy(mnt_pmap, &save_mnt, sizeof(*mnt_pmap));
@@ -338,8 +677,10 @@ static int probe_statd(void)
 	return 1;
 }
 
-/*
- * Attempt to start rpc.statd
+/**
+ * start_statd - attempt to start rpc.statd
+ *
+ * Returns 1 if statd is running; otherwise zero.
  */
 int start_statd(void)
 {
@@ -362,3 +703,336 @@ int start_statd(void)
 
 	return 0;
 }
+
+/**
+ * nfs_call_umount - ask the server to remove a share from it's rmtab
+ * @mnt_server: address of RPC MNT program server
+ * @argp: directory path of share to "unmount"
+ *
+ * Returns one if the unmount call succeeded; zero if the unmount
+ * failed for any reason.
+ *
+ * Note that a side effect of calling this function is that rpccreateerr
+ * is set.
+ */
+int nfs_call_umount(clnt_addr_t *mnt_server, dirpath *argp)
+{
+	CLIENT *clnt;
+	enum clnt_stat res = 0;
+	int msock;
+
+	if (!probe_mntport(mnt_server))
+		return 0;
+	clnt = mnt_openclnt(mnt_server, &msock);
+	if (!clnt)
+		return 0;
+	res = clnt_call(clnt, MOUNTPROC_UMNT,
+			(xdrproc_t)xdr_dirpath, (caddr_t)argp,
+			(xdrproc_t)xdr_void, NULL,
+			TIMEOUT);
+	mnt_closeclnt(clnt, msock);
+
+	if (res == RPC_SUCCESS)
+		return 1;
+	return 0;
+}
+
+/**
+ * mnt_openclnt - get a handle for a remote mountd service
+ * @mnt_server: address and pmap arguments of mountd service
+ * @msock: returns a file descriptor of the underlying transport socket
+ *
+ * Returns an active handle for the remote's mountd service
+ */
+CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
+{
+	struct sockaddr_in *mnt_saddr = &mnt_server->saddr;
+	struct pmap *mnt_pmap = &mnt_server->pmap;
+	CLIENT *clnt = NULL;
+
+	mnt_saddr->sin_port = htons((u_short)mnt_pmap->pm_port);
+	*msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, MOUNT_TIMEOUT,
+				TRUE, FALSE);
+	if (*msock == RPC_ANYSOCK) {
+		if (rpc_createerr.cf_error.re_errno == EADDRINUSE)
+			/*
+			 * Probably in-use by a TIME_WAIT connection,
+			 * It is worth waiting a while and trying again.
+			 */
+			rpc_createerr.cf_stat = RPC_TIMEDOUT;
+		return NULL;
+	}
+
+	switch (mnt_pmap->pm_prot) {
+	case IPPROTO_UDP:
+		clnt = clntudp_bufcreate(mnt_saddr,
+					 mnt_pmap->pm_prog, mnt_pmap->pm_vers,
+					 RETRY_TIMEOUT, msock,
+					 MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
+		break;
+	case IPPROTO_TCP:
+		clnt = clnttcp_create(mnt_saddr,
+				      mnt_pmap->pm_prog, mnt_pmap->pm_vers,
+				      msock,
+				      MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
+		break;
+	}
+	if (clnt) {
+		/* try to mount hostname:dirname */
+		clnt->cl_auth = authunix_create_default();
+		return clnt;
+	}
+	return NULL;
+}
+
+/**
+ * mnt_closeclnt - terminate a handle for a remote mountd service
+ * @clnt: pointer to an active handle for a remote mountd service
+ * @msock: file descriptor of the underlying transport socket
+ *
+ */
+void mnt_closeclnt(CLIENT *clnt, int msock)
+{
+	auth_destroy(clnt->cl_auth);
+	clnt_destroy(clnt);
+	close(msock);
+}
+
+/**
+ * clnt_ping - send an RPC ping to the remote RPC service endpoint
+ * @saddr: server's address
+ * @prog: target RPC program number
+ * @vers: target RPC version number
+ * @prot: target RPC protocol
+ * @caddr: filled in with our network address
+ *
+ * Sigh... getport() doesn't actually check the version number.
+ * In order to make sure that the server actually supports the service
+ * we're requesting, we open and RPC client, and fire off a NULL
+ * RPC call.
+ *
+ * caddr is the network address that the server will use to call us back.
+ * On multi-homed clients, this address depends on which NIC we use to
+ * route requests to the server.
+ *
+ * Returns one if successful, otherwise zero.
+ */
+int clnt_ping(struct sockaddr_in *saddr, const unsigned long prog,
+		const unsigned long vers, const unsigned int prot,
+		struct sockaddr_in *caddr)
+{
+	CLIENT *clnt = NULL;
+	int sock, stat;
+	static char clnt_res;
+	struct sockaddr dissolve;
+
+	rpc_createerr.cf_stat = stat = 0;
+	sock = get_socket(saddr, prot, CONNECT_TIMEOUT, FALSE, TRUE);
+	if (sock == RPC_ANYSOCK) {
+		if (rpc_createerr.cf_error.re_errno == ETIMEDOUT) {
+			/*
+			 * TCP timeout. Bubble up the error to see 
+			 * how it should be handled.
+			 */
+			rpc_createerr.cf_stat = RPC_TIMEDOUT;
+		}
+		return 0;
+	}
+
+	if (caddr) {
+		/* Get the address of our end of this connection */
+		socklen_t len = sizeof(*caddr);
+		if (getsockname(sock, caddr, &len) != 0)
+			caddr->sin_family = 0;
+	}
+
+	switch(prot) {
+	case IPPROTO_UDP:
+		/* The socket is connected (so we could getsockname successfully),
+		 * but some servers on multi-homed hosts reply from
+		 * the wrong address, so if we stay connected, we lose the reply.
+		 */
+		dissolve.sa_family = AF_UNSPEC;
+		connect(sock, &dissolve, sizeof(dissolve));
+
+		clnt = clntudp_bufcreate(saddr, prog, vers,
+					 RETRY_TIMEOUT, &sock,
+					 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
+		break;
+	case IPPROTO_TCP:
+		clnt = clnttcp_create(saddr, prog, vers, &sock,
+				      RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
+		break;
+	}
+	if (!clnt) {
+		close(sock);
+		return 0;
+	}
+	memset(&clnt_res, 0, sizeof(clnt_res));
+	stat = clnt_call(clnt, NULLPROC,
+			 (xdrproc_t)xdr_void, (caddr_t)NULL,
+			 (xdrproc_t)xdr_void, (caddr_t)&clnt_res,
+			 TIMEOUT);
+	if (stat) {
+		clnt_geterr(clnt, &rpc_createerr.cf_error);
+		rpc_createerr.cf_stat = stat;
+	}
+	clnt_destroy(clnt);
+	close(sock);
+
+	if (stat == RPC_SUCCESS)
+		return 1;
+	else
+		return 0;
+}
+
+/**
+ * get_client_address - acquire our local network address
+ * @saddr: server's address
+ * @caddr: filled in with our network address
+ *
+ * Discover a network address that the server will use to call us back.
+ * On multi-homed clients, this address depends on which NIC we use to
+ * route requests to the server.
+ *
+ * Use a connected datagram socket so as not to leave a socket in TIME_WAIT.
+ *
+ * Returns one if successful, otherwise zero.
+ */
+int get_client_address(struct sockaddr_in *saddr, struct sockaddr_in *caddr)
+{
+	socklen_t len = sizeof(*caddr);
+	int socket, err;
+
+	socket = get_socket(saddr, IPPROTO_UDP, CONNECT_TIMEOUT, FALSE, TRUE);
+	if (socket == RPC_ANYSOCK)
+		return 0;
+
+	err = getsockname(socket, caddr, &len);
+	close(socket);
+
+	if (err && verbose) {
+		nfs_error(_("%s: getsockname failed: %s"),
+				progname, strerror(errno));
+		return 0;
+	}
+	return 1;
+}
+
+/*
+ * Try a getsockname() on a connected datagram socket.
+ *
+ * Returns 1 and fills in @buf if successful; otherwise, zero.
+ *
+ * A connected datagram socket prevents leaving a socket in TIME_WAIT.
+ * This conserves the ephemeral port number space, helping reduce failed
+ * socket binds during mount storms.
+ */
+static int nfs_ca_sockname(const struct sockaddr *sap, const socklen_t salen,
+			   struct sockaddr *buf, socklen_t *buflen)
+{
+	struct sockaddr_in sin = {
+		.sin_family		= AF_INET,
+		.sin_addr.s_addr	= htonl(INADDR_ANY),
+	};
+	struct sockaddr_in6 sin6 = {
+		.sin6_family		= AF_INET6,
+		.sin6_addr		= IN6ADDR_ANY_INIT,
+	};
+	int sock;
+
+	sock = socket(sap->sa_family, SOCK_DGRAM, IPPROTO_UDP);
+	if (sock < 0)
+		return 0;
+
+	switch (sap->sa_family) {
+	case AF_INET:
+		if (bind(sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
+			close(sock);
+			return 0;
+		}
+		break;
+	case AF_INET6:
+		if (bind(sock, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) {
+			close(sock);
+			return 0;
+		}
+		break;
+	default:
+		errno = EAFNOSUPPORT;
+		return 0;
+	}
+
+	if (connect(sock, sap, salen) < 0) {
+		close(sock);
+		return 0;
+	}
+
+	return !getsockname(sock, buf, buflen);
+}
+
+/*
+ * Try to generate an address that prevents the server from calling us.
+ *
+ * Returns 1 and fills in @buf if successful; otherwise, zero.
+ */
+static int nfs_ca_gai(const struct sockaddr *sap, const socklen_t salen,
+		      struct sockaddr *buf, socklen_t *buflen)
+{
+	struct addrinfo *gai_results;
+	struct addrinfo gai_hint = {
+		.ai_family	= sap->sa_family,
+		.ai_flags	= AI_PASSIVE,	/* ANYADDR */
+	};
+
+	if (getaddrinfo(NULL, "", &gai_hint, &gai_results))
+		return 0;
+
+	*buflen = gai_results->ai_addrlen;
+	memcpy(buf, gai_results->ai_addr, *buflen);
+
+	freeaddrinfo(gai_results);
+
+	return 1;
+}
+
+/**
+ * nfs_callback_address - acquire our local network address
+ * @sap: pointer to address of remote
+ * @sap_len: length of address
+ * @buf: pointer to buffer to be filled in with local network address
+ * @buflen: IN: length of buffer to fill in; OUT: length of filled-in address
+ *
+ * Discover a network address that an NFSv4 server can use to call us back.
+ * On multi-homed clients, this address depends on which NIC we use to
+ * route requests to the server.
+ *
+ * Returns 1 and fills in @buf if an unambiguous local address is
+ * available; returns 1 and fills in an appropriate ANYADDR address
+ * if a local address isn't available; otherwise, returns zero.
+ */
+int nfs_callback_address(const struct sockaddr *sap, const socklen_t salen,
+			 struct sockaddr *buf, socklen_t *buflen)
+{
+	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
+
+	if (nfs_ca_sockname(sap, salen, buf, buflen) == 0)
+		if (nfs_ca_gai(sap, salen, buf, buflen) == 0)
+			goto out_failed;
+
+	/*
+	 * The server can't use an interface ID that was generated
+	 * here on the client, so always clear sin6_scope_id.
+	 */
+	if (sin6->sin6_family == AF_INET6)
+		sin6->sin6_scope_id = 0;
+
+	return 1;
+
+out_failed:
+	*buflen = 0;
+	if (verbose)
+		nfs_error(_("%s: failed to construct callback address"));
+	return 0;
+
+}