+
+/**
+ * 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 queries don't actually check the version number.
+ * In order to make sure that the server actually supports the service
+ * we're requesting, we open an 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;
+}
+
+/*
+ * 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,
+ 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, 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"),
+ progname);
+ return 0;
+}
+
+/*
+ * "nfsprog" is supported only by the legacy mount command. The
+ * kernel mount client does not support this option.
+ *
+ * Returns TRUE if @program contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_nfs_program(struct mount_options *options, unsigned long *program)
+{
+ long tmp;
+
+ switch (po_get_numeric(options, "nfsprog", &tmp)) {
+ case PO_NOT_FOUND:
+ break;
+ case PO_FOUND:
+ if (tmp > 0) {
+ *program = tmp;
+ return 1;
+ }
+ case PO_BAD_VALUE:
+ return 0;
+ }
+
+ /*
+ * NFS RPC program wasn't specified. The RPC program
+ * cannot be determined via an rpcbind query.
+ */
+ *program = nfs_getrpcbyname(NFSPROG, nfs_nfs_pgmtbl);
+ return 1;
+}
+
+/*
+ * Returns TRUE if @version contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_nfs_version(struct mount_options *options, unsigned long *version)
+{
+ long tmp;
+
+ switch (po_rightmost(options, nfs_version_opttbl)) {
+ case 0: /* v2 */
+ *version = 2;
+ return 1;
+ case 1: /* v3 */
+ *version = 3;
+ return 1;
+ case 2: /* vers */
+ switch (po_get_numeric(options, "vers", &tmp)) {
+ case PO_FOUND:
+ if (tmp >= 2 && tmp <= 3) {
+ *version = tmp;
+ return 1;
+ }
+ return 0;
+ case PO_NOT_FOUND:
+ nfs_error(_("%s: option parsing error\n"),
+ progname);
+ case PO_BAD_VALUE:
+ return 0;
+ }
+ case 3: /* nfsvers */
+ switch (po_get_numeric(options, "nfsvers", &tmp)) {
+ case PO_FOUND:
+ if (tmp >= 2 && tmp <= 3) {
+ *version = tmp;
+ return 1;
+ }
+ return 0;
+ case PO_NOT_FOUND:
+ nfs_error(_("%s: option parsing error\n"),
+ progname);
+ case PO_BAD_VALUE:
+ return 0;
+ }
+ }
+
+ /*
+ * NFS version wasn't specified. The pmap version value
+ * will be filled in later by an rpcbind query in this case.
+ */
+ *version = 0;
+ return 1;
+}
+
+/*
+ * Returns TRUE if @protocol contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_nfs_protocol(struct mount_options *options, unsigned long *protocol)
+{
+ char *option;
+
+ switch (po_rightmost(options, nfs_transport_opttbl)) {
+ case 0: /* udp */
+ *protocol = IPPROTO_UDP;
+ return 1;
+ case 1: /* tcp */
+ *protocol = IPPROTO_TCP;
+ return 1;
+ case 2: /* proto */
+ option = po_get(options, "proto");
+ if (option) {
+ if (strcmp(option, "tcp") == 0) {
+ *protocol = IPPROTO_TCP;
+ return 1;
+ }
+ if (strcmp(option, "udp") == 0) {
+ *protocol = IPPROTO_UDP;
+ return 1;
+ }
+ return 0;
+ }
+ }
+
+ /*
+ * NFS transport protocol wasn't specified. The pmap
+ * protocol value will be filled in later by an rpcbind
+ * query in this case.
+ */
+ *protocol = 0;
+ return 1;
+}
+
+/*
+ * Returns TRUE if @port contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_nfs_port(struct mount_options *options, unsigned long *port)
+{
+ long tmp;
+
+ switch (po_get_numeric(options, "port", &tmp)) {
+ case PO_NOT_FOUND:
+ break;
+ case PO_FOUND:
+ if (tmp >= 1 && tmp <= 65535) {
+ *port = tmp;
+ return 1;
+ }
+ case PO_BAD_VALUE:
+ return 0;
+ }
+
+ /*
+ * NFS service port wasn't specified. The pmap port value
+ * will be filled in later by an rpcbind query in this case.
+ */
+ *port = 0;
+ return 1;
+}
+
+/*
+ * "mountprog" is supported only by the legacy mount command. The
+ * kernel mount client does not support this option.
+ *
+ * Returns TRUE if @program contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_mount_program(struct mount_options *options, unsigned long *program)
+{
+ long tmp;
+
+ switch (po_get_numeric(options, "mountprog", &tmp)) {
+ case PO_NOT_FOUND:
+ break;
+ case PO_FOUND:
+ if (tmp > 0) {
+ *program = tmp;
+ return 1;
+ }
+ case PO_BAD_VALUE:
+ return 0;
+ }
+
+ /*
+ * MNT RPC program wasn't specified. The RPC program
+ * cannot be determined via an rpcbind query.
+ */
+ *program = nfs_getrpcbyname(MOUNTPROG, nfs_mnt_pgmtbl);
+ return 1;
+}
+
+/*
+ * Returns TRUE if @version contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_mount_version(struct mount_options *options, unsigned long *version)
+{
+ long tmp;
+
+ switch (po_get_numeric(options, "mountvers", &tmp)) {
+ case PO_NOT_FOUND:
+ break;
+ case PO_FOUND:
+ if (tmp >= 1 && tmp <= 4) {
+ *version = tmp;
+ return 1;
+ }
+ case PO_BAD_VALUE:
+ return 0;
+ }
+
+ /*
+ * MNT version wasn't specified. The pmap version value
+ * will be filled in later by an rpcbind query in this case.
+ */
+ *version = 0;
+ return 1;
+}
+
+/*
+ * Returns TRUE if @protocol contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_mount_protocol(struct mount_options *options, unsigned long *protocol)
+{
+ char *option;
+
+ option = po_get(options, "mountproto");
+ if (option) {
+ if (strcmp(option, "tcp") == 0) {
+ *protocol = IPPROTO_TCP;
+ return 1;
+ }
+ if (strcmp(option, "udp") == 0) {
+ *protocol = IPPROTO_UDP;
+ return 1;
+ }
+ return 0;
+ }
+
+ /*
+ * MNT transport protocol wasn't specified. If the NFS
+ * transport protocol was specified, use that; otherwise
+ * set @protocol to zero. The pmap protocol value will
+ * be filled in later by an rpcbind query in this case.
+ */
+ return nfs_nfs_protocol(options, protocol);
+}
+
+/*
+ * Returns TRUE if @port contains a valid value for this option,
+ * or FALSE if the option was specified with an invalid value.
+ */
+static int
+nfs_mount_port(struct mount_options *options, unsigned long *port)
+{
+ long tmp;
+
+ switch (po_get_numeric(options, "mountport", &tmp)) {
+ case PO_NOT_FOUND:
+ break;
+ case PO_FOUND:
+ if (tmp >= 1 && tmp <= 65535) {
+ *port = tmp;
+ return 1;
+ }
+ case PO_BAD_VALUE:
+ return 0;
+ }
+
+ /*
+ * MNT service port wasn't specified. The pmap port value
+ * will be filled in later by an rpcbind query in this case.
+ */
+ *port = 0;
+ return 1;
+}
+
+/**
+ * nfs_options2pmap - set up pmap structs based on mount options
+ * @options: pointer to mount options
+ * @nfs_pmap: OUT: pointer to pmap arguments for NFS server
+ * @mnt_pmap: OUT: pointer to pmap arguments for mountd server
+ *
+ * Returns TRUE if the pmap options specified in @options have valid
+ * values; otherwise FALSE is returned.
+ */
+int nfs_options2pmap(struct mount_options *options,
+ struct pmap *nfs_pmap, struct pmap *mnt_pmap)
+{
+ if (!nfs_nfs_program(options, &nfs_pmap->pm_prog))
+ return 0;
+ if (!nfs_nfs_version(options, &nfs_pmap->pm_vers))
+ return 0;
+ if (!nfs_nfs_protocol(options, &nfs_pmap->pm_prot))
+ return 0;
+ if (!nfs_nfs_port(options, &nfs_pmap->pm_port))
+ return 0;
+
+ if (!nfs_mount_program(options, &mnt_pmap->pm_prog))
+ return 0;
+ if (!nfs_mount_version(options, &mnt_pmap->pm_vers))
+ return 0;
+ if (!nfs_mount_protocol(options, &mnt_pmap->pm_prot))
+ return 0;
+ if (!nfs_mount_port(options, &mnt_pmap->pm_port))
+ return 0;
+
+ return 1;
+}